Beijing, China

Beijing Forestry University is a multi-disciplinary university under the administration of the Ministry of Education of the People's Republic of China. As one of the key national universities under the Ministry of Education, the university provides advanced education in the fields of forestry, Biological science, Biotechnology, ecology and environmental studies. It was one of the first universities to be admitted into the 211 Project and the 21st-century Educational Vitalization Action Program. Wikipedia.

Time filter

Source Type

Yang J.,Tsinghua University | Yang J.,Joint Center for Global Change Studies | Yan P.,Beijing Forestry University | He R.,Hainan University | Song X.,Hainan University
Landscape and Urban Planning | Year: 2017

Urban vegetation is influenced by prior land use due to the dynamic nature of urban landscape. However, limited information is available on how strongly the land-use legacy impacts the diversity of urban vegetation, especially in areas of rapid urbanization. This study quantified the land-use legacy effect on taxonomic and functional diversity of woody plants in Haikou, China. We collected data on land use, percentages of woody vegetation cover, and abundance of woody plants from 461 randomly distributed sample plots. The influence of land-use legacy was examined by analyzing the land-use history of sample plots and taxonomic and functional α- and β-diversity of woody plants. The relative importance of the land use and the percentage of woody vegetation cover on the diversity of woody plants were analyzed using the boosted regression tree model. The result showed that the land-use legacy effect caused significant divergence in taxonomic and functional diversity of woody plants and the effect was most obvious in sites where the lands were currently used as residential areas. Remnant trees, shrubs, and possibly shrubs growing from seed banks and roots contributed to this legacy effect. We also found that taxonomic and functional α-diversities of trees in a site were influenced by how frequent the land use of the place was changed and what type of land use that the place ended up with. Based on our findings, we recommend conservation programs in rapidly urbanizing regions give more attention to vegetation in residential areas and particularly species with low utilitarian value. © 2017 Elsevier B.V.

Zhang L.,Beijing Forestry University | Sun X.,Beijing Forestry University
Bioresource Technology | Year: 2017

The objective of this work was to study the two-stage composting of green waste (GW) as affected by addition of fish pond sediment (FPS; at 0, 25, and 35%) and/or rock phosphate (RP; at 0, 10, and 15%). The combined addition of FPS and RP greatly accelerated GW degradation and improved compost quality in terms of composting temperature, windrow volume, pH, electrical conductivity (EC), cation exchange capacity (CEC), NH3 emission, microbial biomass, enzyme activities, nutrient content, and seed germination. The two-stage composting was optimal with the combined addition of 25% FPS and 15% RP. In addition to producing the highest quality compost product, the optimal combination resulted a mature compost in only 22 days rather than in the 90–270 days required with traditional composting. © 2017 Elsevier Ltd

Yin A.,Beijing Forestry University | Yang J.,Beijing Forestry University
Macromolecular Chemistry and Physics | Year: 2017

Interactions between polymer chains and nanoparticles can play a dominant role in composites mechanics, yet the control of such interfacial dynamics is still a significant challenge. This paper reports the effect of pH on cellulose nanofibrils (CNFs) transient hydrogels network mechanics via interfacial ionic cross-linking bonds. For this purpose, carboxylated CNFs are incorporated with amine groups terminated 8-arm poly(ethylene glycol) (PEG-NH2) to assemble the first noncovalent network via reversible ionic interactions at the CNF surfaces, where the end-group acrylate modified linear difunctional PEG forms the second lightly covalent cross-linked network. The viscoelastic properties of the supramolecular gels are examined as a function of pH, and the unique transient mechanics resulting from CNF-PEG complexation structures show that the processing from acidic-to-alkaline pH change leads to the gel cross-links transition from covalent type to covalent-noncovalent hybrid one. This finding offers an alternative way to tune CNF gels mechanical reinforcement and sheds light on the pH dependence of network architectural changes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Luo M.,Beijing Forestry University | Zheng X.,Beijing Forestry University | Du Y.,Ecological Civilization Construction Bureau of Qingzhen City in Guizhou Province
Nature Environment and Pollution Technology | Year: 2017

The study of the natural regeneration of an artificial Platycladus orientalis stand is important in order to reflect the potential trend of the stand. This field investigation was carried out in the Shisanling forest farm in Beijing. We analysed the factors that influenced the natural regeneration using the gray correlation method. The results showed that the regeneration status was bad in height classes of 0- 30 cm and 30-50 cm, while it was moderate in the height class of >50 cm; the overall regeneration status was moderate. Eight factors that affected the natural regeneration, in a descending order, are: Altitude, aspect, soil depth, slope position, stand density, gradient, shrub-herb cover and litter thickness. It was difficult to satisfy the demand of stand self-replacement because the natural regeneration of artificial P. orientalis stands was poor.

Zhang N.,Beijing Forestry University | Liu C.,Beijing Institute of Water | Qi F.,Beijing Forestry University | Xu B.,Chinese Research Academy of Environmental Sciences
RSC Advances | Year: 2017

Critical algal blooms in lakes increased the concentration of algal organic matter (AOM), significantly altering the drinking water treatment requirements, including coagulation, oxidation and disinfection. This study utilized Microcystis aeruginosa (cyanobacteria), Scenedesmus quadricauda (Chlorella) and Nitzschia palea (diatom) as models to investigate the AOM's primary characteristics and their contribution to the formation of chloroacetamides as novel disinfection byproducts (DBPs). Spectral analysis was used to characterize the proteins, carbohydrates and amino acids in AOM. The generation of chloroacetamides during chlor(am)ination was determined by gas chromatography with electron capture detection. Although Microcystis aeruginosa is the dominant species in freshwater worldwide, the AOM of Nitzschia palea showed the highest dissovled organic carbon (DOC) formation (4.02 or 1.42 ng per cell in extracellular organic matter (EOM) or intracellular organic matter (IOM), respectively). Scenedesmus quadricauda, as a typical green algae, showed the greatest formation potential of chloroacetamides in chlor(am)ination. Monochloroacetamide was the dominant chloroacetamide, which has not previously been reported and differed from the results reported for other precursors. In summary, AOM should be considered an important precursor for the formation of chloroacetamides. © The Royal Society of Chemistry.

Zhou P.,Beijing Forestry University | Lin Z.,Beijing Forestry University
Journal of Computational and Theoretical Nanoscience | Year: 2016

The government investment project with large investment scale, wide range, strong public welfare, high degree of attention by the public. In this paper, from the analysis on the characteristics of government investment projects, in terms of project management system, project management concepts and project management operational mechanism analysis to the project management problem and relevant examples, points out its shortage in project management, find out the cause of the problem, finally according to the problems of government investment project management, targeted put forward the concrete measures and methods of strengthening and improving, aims to provide the basis for the future similar government investment project management. © 2016 American Scientific Publishers All rights reserved.

Guo X.,Beijing Forestry University | Cao J.,Beijing Forestry University | Chen Y.,Beijing Forestry University
Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica | Year: 2016

Dodecyl alcohol (DA) was coated with melamine-formaldehyde (MF) and polyethylene glycol modified melamine-formaldehyde (PMF) resin to prepare microencapsulated phase change materials (MicroPCMs). They were respectively added into wood flour/high-density polyethylene (WF/HDPE) composites to obtain MicroPCMs-WF/HDPE composites with thermal energy storage capacity. The surface morphology and mechanical properties of MicroPCMs were characterized by SEM, FTIR and nanoindentor etc. The physical and mechanical and thermal properties of MicroPCMs-WF/HDPE composites were investigated. The results show that the elastic modulus and hardness of modified microcapsules (PMF-MicropCMs) increase by 13.9% and 30.0% compared to unmodified microcapsules (MF-MicroPCMs) after polyethylene glycol modification, respectively. The melting temperature range (22.2-28.7 ℃) of MicroPCMs-WF/HDPE composites fits the human comfortable temperature range, and the temperature change speed is lower than pure WF/HDPE composites. The incorporation of MicroPCMs has a negative effect on flexural and tensile properties of WF/HDPE composites but favor the moisture absorption performance, impact strength and surface hardness; All properties of PMF-MicroPCMs-WF/HDPE composites are better than those of MF-MicroPCMs-WF/HDPE composites. All the mechanical properties meet the requirements for wood plastic decorative boards. © 2016, BUAA Culture Media Group Ltd. All right reserved.

Yuan Y.,Beijing Forestry University | Chen J.-J.,Beijing Forestry University | He S.-H.,Beijing Forestry University
Mycoscience | Year: 2017

A new poroid wood-inhabiting fungal genus, Geliporus, is proposed based on morphological characters and molecular data. It is typified by G. exilisporus comb. nov. (Basionym: Inonotus exilisporus), and characterized by resupinate basidiomata darkening in potassium hydroxide, a monomitic hyphal system with simple-septate and hyaline to yellowish generative hyphae, and hyaline, thin-walled, and cylindrical to oblong-ellipsoid basidiospores. Results of phylogenetic analyses inferred from the 5.8S and nLSU rDNA sequences indicate that G. exilisporus belongs to the Phanerochaetaceae in Polyporales and is closely related to the genus of Hyphodermella. © 2017 The Mycological Society of Japan.

Li Y.,Beijing Forestry University | Song Y.,Beijing Forestry University | Xu B.,Beijing Forestry University | Xie J.,Beijing Forestry University | Zhang D.,Beijing Forestry University
Tree Physiology | Year: 2017

The C-repeat binding factors (CBFs), also termed dehydration-responsive element-binding protein 1 (DREB1) family members, play crucial roles in the acquisition of stress tolerance, but in trees, the underlying mechanisms of stress tolerance remain elusive. To gain insight into these mechanisms, we isolated five CBF1 orthologs from four poplar sections (Populus spp.) and assessed their expression under drought, cold, heat and salt stress conditions. Globally induced expression in response to cold suggested a correlation between poplar CBF1 expression and the acquisition of cold tolerance. Responses that varied between sections may reflect section-specific stress tolerance mechanisms, suggesting an effect of ecological context on the development of CBF1- mediated stress tolerance in poplar. We then used a genome-wide search strategy in Populus trichocarpa to predict 2263 putative CBF target genes; the identified genes participate in multiple biological processes and pathways. Almost all of the putative target genes contained multiple cis-acting elements that mediate responses to various environmental and endogenous signals, consistent with an important role of CBF1s in an integrated cold regulatory network. Finally, analysis of an association population of 528 individuals of Populus simonii identified six single-nucleotide polymorphisms (false discovery rate Q < 0.10) significantly (P < 0.005) associated with malondialdehyde production and electrolyte leakage, suggesting the potential importance of PsCBF1 in the regulation of some membrane-related functions. Our findings provide new insights into the function of PsCBF1 and shed light on the CBF-mediated regulatory network in poplar. © The Author 2016.

Zhao C.,Beijing Forestry University | Tian M.,Beijing Forestry University | Li Y.,Beijing Forestry University | Zhang P.,Beijing Forestry University
Euphytica | Year: 2017

To reveal the mechanism of low triploid production, meiotic observation, induction of 2n pollen by colchicine, hybridization of colchicine-induced 2n pollen and pollen germination were conducted in Populus tomentosa clone 5088. Meiosis of the PMCs was initiated 24 h after it was cultured in the greenhouse. Results showed that the meiosis developed in a consecutive, asynchronous process. Analysis of the occurrence rate of colchicine-induced 2n pollen using the GLM-univariate revealed significant differences among the dominant meiotic stages (F = 45.822, P = 0.000). Significant differences also occurred among various colchicine injection times (F = 10.150, P = 0.004). The most effective stage for colchicine-induced 2n pollen occurred between the zygotene to diakinesis substages. Sixty-eight triploids were confirmed with both flow cytometric analysis and chromosome number-counting among the 3346 offspring. The highest triploid induction rate was 13.2%—significantly lower than the expected triploid production rate of 47.0%—indicating that the colchicine-induced 2n pollen was weak during fertilization. We found positive correlation between the efficiency of triploid production and the frequency of colchicine-induced 2n pollen (r = 0.961, P = 0.001) which suggests that the triploid production rate increased as the occurrence rate of colchicine-induced 2n pollen increased. Analysis using the GLM-univariate indicated that both pollen types (F = 87.50, P < 0.001) and durations of pollen germination (F = 7.61, P = 0.002) did have significant effects on the lengths of pollen-tubes. Haploid pollen-tubes were significantly longer than colchicine-induced 2n pollen-tubes. This suggests that haploid pollen has an advantage during fertilization. © 2017, Springer Science+Business Media Dordrecht.

Chang Z.,Beijing Forestry University | Sun B.,Beijing Forestry University | Li D.,North Dakota State University
European Journal of Horticultural Science | Year: 2017

Perennial ryegrass (Lolium perenne L.) is an important turf and forage species in mild temperate regions. In cold regions, it is vulnerable to winter kill. The objective of this study was to investigate possible associations between cold tolerance and morphological traits that regulate water movement in perennial ryegrass. Cultivars ‘Uno’, ‘Brightstar SLT’, ‘Fiesta’, ‘Evening Shade’, ‘NK-200’, and ‘Linn’, representing different levels of cold tolerance and winter hardiness, were used in the study. Previously reported cold tolerant cultivars, ‘Uno’ and ‘Brightstar SLT’, showed smaller but higher density of stomata than cold sensitive cultivars such as ‘Linn’ and ‘NK-200’. In addition, cold tolerant cultivars had either higher density of short cells or higher density of hairs in the epidermis compared to the cold sensitive cultivars. Water wetting angles on the upper epidermis also indicated that ‘Uno’ had a better protection from water loss than cold sensitive cultivars, especially ‘Linn’. The water loss rate (% per day) was significantly higher for ‘Linn’ than ‘Uno’, which were 3.39 and 2.27, respectively. Simulated wind desiccation combined with freezing at -10°C after cold acclimation further showed that stronger water withholding ability contributed to the increased freezing tolerance. The results suggest that including water conserving morphologies in the selection process may help breeding for freeze tolerant perennial ryegrass. © ISHS 2017.

Yuan D.,Beijing Forestry University | Wang Y.,Beijing Forestry University | Qian X.,Beijing Forestry University
International Biodeterioration and Biodegradation | Year: 2017

The floc rupture and fractal structure during the ultrasonic pretreatment, rheological parameters as well as bound water content of activated sludge before/after extracellular polymeric substances (EPS) extraction was investigated to examine the variations of internal structure and moisture distribution in activated sludge with stratified EPS extraction. It was observed that the floc disruption was dominated by the model of large-scale fragmentation initially and by smaller-scale surface erosion subsequently for activated sludge before/after EPS extraction. Activated sludge with tightly bound EPS (TB-EPS) showed greater mass fractal dimension (Df) and rheological parameters hysteresis loop area, limiting viscosity (η∞), yield stress (τy), energy of cohesion of network structure (Ec) and shear modulus (G) than the other sludge samples, indicating that activated sludge after loosely bound EPS (LB-EPS) extraction exhibited a denser and stronger network structure. A water classification is also proposed: free water (bulk water and some portion of interstitial water) and bound water (osmotic, surface and intracellular water). The osmotic water (interstitial-bound water) in the LB-EPS fraction (4.3% of the total water content) exhibited much more than that in the TB-EPS (0.2% of the total water content). Bound water (surface and intracellular water) in the TB-EPS and Pellet comes to be the subject to be treated after mechanical dewatering. © 2016 Elsevier Ltd

Xue Z.,Beijing Forestry University | Jiang J.,Renmin University of China | Ma M.-G.,Beijing Forestry University | Li M.-F.,Beijing Forestry University | Mu T.,Renmin University of China
ACS Sustainable Chemistry and Engineering | Year: 2017

Development of heterogeneous catalysts for the cycloaddition of CO2 with epoxides to prepare cyclic carbonates is a hot topic in the field of CO2 transformation. Herein, a rare-earth-metal gadolinium-based metal-organic framework (Gd-MOF) was synthesized from GdCl3 and pyromellitic dianhydride in N,N-dimethylformamide, which was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption, and Fourier transform infrared (FT-IR) spectroscopy. The synthesized Gd-MOF could be used as heterogeneous catalyst for the cycloaddition of CO2 with epoxides in the presence of quaternary ammonium salts, and Gd-MOF/n-Bu4NBr showed the best performance for the cycloaddition of CO2 with various epoxides to form the corresponding cyclic carbonates due to the excellent synergetic effect. Furthermore, the prepared Gd-MOF could be used as heterogeneous catalyst for alcoholysis of various epoxides to form β-alkoxy alcohols effectively. © 2017 American Chemical Society.

Wang J.,China Institute of Water Resources and Hydropower Research | Li J.,China Institute of Water Resources and Hydropower Research | Guan H.,Beijing Forestry University
Irrigation and Drainage | Year: 2017

Appropriate drip irrigation system uniformity can maintain a higher crop yield and reduce the initial investment of the system. In this study, investigating the optimal drip system uniformity for cotton, a two-dimensional soil water transport and crop growth coupling model was calibrated and validated by soil water dynamics, crop growth indices and cotton yield obtained from mulched drip irrigation field experiments in an arid region of Xinjiang Uygur Autonomous Region, China. The model performed well with the normalized root mean square error of 2.6-22.6% for soil moisture, 6.3-14.1% for leaf area index, 4.9-7.2% for above-ground biomass, and with the difference ranging from 2.5 to 8.2% for seed cotton yield (SCY). Next, SCYs were simulated under five Christiansen uniformity coefficients (CUs) of 55, 65, 75, 85 and 95% with three irrigation levels of 50, 75 and 100% full irrigation treatment. The predicted SCY was found to decrease as CU decreased under different irrigation treatments, and the more obvious effect of CU on SCY at 75 and 100% full irrigation treatment was obtained. In addition, SCY increased by 2.8-8.0% when CU increased from 55 to 75%, and increased by 0.1-4.6% when CU increased from 75 to 95%. Therefore, a target drip irrigation uniformity of CU = 75% was recommended to obtain a higher cotton yield, while maintaining a lower installation cost in the arid region. © 2017 John Wiley & Sons, Ltd.

Ma Y.,Beijing Forestry University | Shi H.,Beijing Forestry University | Liang H.,CAS Institute of Zoology
Zootaxa | Year: 2017

The Oriental genus Physodera Eschscholtz, 1829 is revised. A key to species is provided, along with distribution maps, and illustrations of habitus and male genitalia of all available species. Two new species are described: Physodera sciakyi sp. n. (type locality: S. Sulawesi, Indonesia), and Physodera unicolor sp. n. (type locality: Zhejiang, China). Three new synonyms are proposed: Physodera parvicollis Van de Poll, 1889 = Physodera eschscholtzii Parry, 1849, Allocota sumatrensis Kirschenhofer, 1996 = Physodera eschscholtzii Parry, 1849, and Physodera noctiluca Mohnike, 1875= Physodera dejeani Eschscholtz, 1829. Copyright © 2017 Magnolia Press.

Hu J.,Beijing Forestry University | Ma X.,Beijing Forestry University | Liu L.,Beijing Center for Physical and Chemical Analysis | Wu Y.,Beijing Center for Physical and Chemical Analysis | Ouyang J.,Beijing Forestry University
Food Chemistry | Year: 2017

Near-infrared (NIR) diffuse reflectance spectroscopy was used to evaluate the quality of fresh chestnuts, which can be affected by mildew, water, and levels of water-soluble sugars. The NIR spectra were determined and then modeling was performed including principal component analysis – discriminant analysis (PCA-DA), soft independent modeling of class analogy (SIMCA), linear discriminant analysis (LDA), and partial least squares (PLS) methods. LDA model was better than PCA-DA model for the discrimination of normal and mildewed chestnuts, and the accuracy rates of calibration and validation were 100% and 96.37%, respectively. Normal and mildewed chestnuts were easily distinguished by the SIMCA classification and showed only 4.7% overlap. A PLS model was established to determine the water and water-soluble sugars in chestnuts. The R2 of calibration and validation were all higher than 0.9, while the root mean square errors (RMSE) were all lower than 0.05, indicating that the established models were successful. © 2017 Elsevier Ltd

Yan G.,Beijing Normal University | Hu R.,Beijing Normal University | Wang Y.,Beijing Normal University | Ren H.,Peking University | And 3 more authors.
IEEE Transactions on Geoscience and Remote Sensing | Year: 2016

Scale effect, which is caused by a combination of model nonlinearity and surface heterogeneity, has been of interest to the remote sensing community for decades. However, there is no current analysis of scale effect in the ground-based indirect measurement of leaf area index (LAI), where model nonlinearity and surface heterogeneity also exist. This paper examines the scale effect on the indirect measurement of LAI. We built multiscale data sets based on realistic scenes and field measurements. We then implemented five representative methods of indirect LAI measurement at scales (segment lengths) that range from meters to hundreds of meters. The results show varying degrees of deviation and fluctuation that exist in all five methods when the segment length is shorter than 20 m. The retrieved LAI from either Beer's law or the gap-size distribution method shows a decreasing trend with increasing segment lengths. The length at which the LAI values begin to stabilize is about a full period of row in row crops and 100 m in broadleaf or coniferous forests. The impacts of segment length on the finite-length averaging method, the combination of gap-size distribution and finite-length methods, and the path-length distribution method are relatively small. These three methods stabilize at the segment scale longer than 20 m in all scenes. We also find that computing the average LAI of all of the short segment lengths, which is commonly done, is not as good as merging these short segments into a longer one and computing the LAI value of the merged one. © 2015 IEEE.

Ren G.-J.,Beijing Forestry University | Wu F.,Beijing Forestry University
Phytotaxa | Year: 2017

A new species, Phylloporia lespedezae, is described from Shanxi Province on the basis of morphological, ecological characters and molecular evidence. It is characterized by having an annual, pileate basidiocarps with wavy edge, duplex context separated by a black line, a monomitic hyphal system with simple septate generative hyphae, the presence of fusoid cystidi-oles, yellowish, broadly ellipsoid, thick-walled basidiospores, and growing on Lespedeza (Fabaceae) only. Phylogenetic analysis based on nuclear large subunit ribosomal DNA (nLSU) strongly support P. lespedezae as a distinct species within the genus of Phylloporia. Detailed description with illustration is provided for the new species and its relationships with similar species are discussed. In addition, a key to all 41 species of Phylloporia is provided. © 2017 Magnolia Press.

Wang W.,Beijing University of Chemical Technology | Li J.,Beijing Forestry University | Sun Q.,Beijing Forestry University | Yu X.,Beijing University of Chemical Technology | And 15 more authors.
Nature Plants | Year: 2017

Chloroplasts divide by binary fission, which is accomplished by the simultaneous constriction of the FtsZ ring on the stromal side of the inner envelope membrane, and the ARC5 ring on the cytosolic side of the outer envelope membrane. The two rings are connected and coordinated mainly by the interaction between the inner envelope membrane protein ARC6 and the outer envelope membrane protein PDV2 in the intermembrane space. The underlying mechanism of this coordination is unclear to date. Here, we solved the crystal structure of the intermembrane space region of the ARC6-PDV2 complex. The results indicated that PDV2 inserts its carboxy terminus into a pocket formed in ARC6, and this interaction further induces the dimerization of the intermembrane space regions of two ARC6 molecules. A pdv2 mutant attenuating PDV2-induced ARC6 dimerization showed abnormal morphology of ARC6 rings and compromised chloroplast division in plant cells. Together, our data reveal that PDV2-induced dimerization of ARC6 plays a critical role in chloroplast division and provide insights into the coordination mechanism of the internal and external plastid division machineries. © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.

Liu P.-L.,Beijing Forestry University | Du L.,Beijing Forestry University | Huang Y.,Peking University | Gao S.-M.,Beijing Forestry University | Yu M.,Beijing Forestry University
BMC Evolutionary Biology | Year: 2017

Background: Leucine-rich repeat receptor-like protein kinases (LRR-RLKs) are the largest group of receptor-like kinases in plants and play crucial roles in development and stress responses. The evolutionary relationships among LRR-RLK genes have been investigated in flowering plants; however, no comprehensive studies have been performed for these genes in more ancestral groups. The subfamily classification of LRR-RLK genes in plants, the evolutionary history and driving force for the evolution of each LRR-RLK subfamily remain to be understood. Results: We identified 119 LRR-RLK genes in the Physcomitrella patens moss genome, 67 LRR-RLK genes in the Selaginella moellendorffii lycophyte genome, and no LRR-RLK genes in five green algae genomes. Furthermore, these LRR-RLK sequences, along with previously reported LRR-RLK sequences from Arabidopsis thaliana and Oryza sativa, were subjected to evolutionary analyses. Phylogenetic analyses revealed that plant LRR-RLKs belong to 19 subfamilies, eighteen of which were established in early land plants, and one of which evolved in flowering plants. More importantly, we found that the basic structures of LRR-RLK genes for most subfamilies are established in early land plants and conserved within subfamilies and across different plant lineages, but divergent among subfamilies. In addition, most members of the same subfamily had common protein motif compositions, whereas members of different subfamilies showed variations in protein motif compositions. The unique gene structure and protein motif compositions of each subfamily differentiate the subfamily classifications and, more importantly, provide evidence for functional divergence among LRR-RLK subfamilies. Maximum likelihood analyses showed that some sites within four subfamilies were under positive selection. Conclusions: Much of the diversity of plant LRR-RLK genes was established in early land plants. Positive selection contributed to the evolution of a few LRR-RLK subfamilies. © 2017 The Author(s).

Liu R.,Chinese Academy of Forestry | Cao J.,Beijing Forestry University | Chen Y.,Beijing Forestry University
Holzforschung | Year: 2017

Wood flour (WF) was modified with sodium-montmorillonite (Na-MMT) and didecyl dimethyl ammonium chloride (DDAC) to form an organo-montmorillonite (OMMT) inside WF at different OMMT concentrations from 0.25 to 1%. The modified WF was blended with polypropylene (PP) to produce PP/WF composites at a weight ratio of 1:1 by compression molding. The composites were immersed in water and their stress relaxation behaviors were investigated at 26, 40, and 60°C, respectively. Results: (1) All composites show stress relaxation with increasing compression testing time, indicating that they have pronounced rheological properties. (2) The stress relaxation becomes more severe with increasing temperature and water immersion time. (3) OMMT improves the stiffness of the composites with slower stress relaxation, and the PP/WF0.5% OMMT seems to perform best among all. © 2017 Walter de Gruyter GmbH, Berlin/Boston.

Ma C.,Beijing Forestry University | Wang Y.-J.,Beijing Forestry University | Du C.,Henan University of Science and Technology
Journal of Mountain Science | Year: 2017

Debris flows can be extremely destructive because they can increase in magnitude via progressive entrainment. In this paper, a total of 18 landslide-type debris flows and 268 channelized debris flows in Wenchuan earthquake and Taiwan region, as well as other regions were collected to analyze the entrainment rate of debris flows in each triggering condition. Results show that there is a power relationship between volume of initial triggered mass and final deposited debris for landslide type debris flow. The debris flows during 2008 and 2013 in Wenchuan earthquake-region have smaller entrainment rate than that from 2001 t0 2009 in Taiwan. The entrainment rate of debris flow events from 2001 to 2009 in Taiwan shows a decaying tendency as elapsed time. Comparison of the entrainment rate in the two earthquake-hit regions with other regions proves that entrainment rate has a close relation with major sediment availability and secondary rainstorm conditions. © 2017, Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg.

Lv X.,Beijing Forestry University | Jing Y.,Beijing Forestry University | Xiao J.,Beijing Forestry University | Zhang Y.,Yale University | And 3 more authors.
Plant Journal | Year: 2017

Arabidopsis hypersensitive-induced reaction (AtHIR) proteins function in plant innate immunity. However, the underlying mechanisms by which AtHIRs participate in plant immunity remain elusive. Here, using VA-TIRFM and FLIM-FRET, we revealed that AtHIR1 is present in membrane microdomains and co-localizes with the membrane microdomain marker REM1.3. Single-particle tracking analysis revealed that membrane microdomains and the cytoskeleton, especially microtubules, restrict the lateral mobility of AtHIR1 at the plasma membrane and facilitate its oligomerization. Furthermore, protein proximity index measurements, fluorescence cross-correlation spectroscopy, and biochemical experiments demonstrated that the formation of the AtHIR1 complex upon pathogen perception requires intact microdomains and cytoskeleton. Taken together, these findings suggest that microdomains and the cytoskeleton constrain AtHIR1 dynamics, promote AtHIR1 oligomerization, and increase the efficiency of the interactions of AtHIR1 with components of the AtHIR1 complex in response to pathogens, thus providing valuable insight into the mechanisms of defense-related responses in plants. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd

Hou J.,Beijing Forestry University | Wang H.,Hulun Buir Bureau of Meteorology | Li Z.,CAS Research Center for Eco Environmental Sciences
Ecological Modelling | Year: 2017

Recently, plant root or crown size has been used in researching spatial relationships between plants and soil resources in most studies, and different methods have been used to address this relationship. However, few studies have reviewed the quantification of the relationship between plants and soil resources, and few studies have explained the roles of different plant functional groups on the soil resource distribution. In this paper, a method called integration of geostatistics, point pattern analysis and spatial comparison (IGPS) was used to quantify this relationship. The relationships between plants and soil resource patterns were evaluated from four plots with different spatial scales and different slopes within the Ziwuling Mountains of China. Several relationships were identified using IGPS. We have proved that in IGPS, the aggregation scale between plants and soil resources has been substituted for root or crown size to deeply reveal the spatial relationship between plants and soil resources. The results confirm that this method can not only determine which plant functional group can be affected by which resource but can also quantify the spatial relationship between plants and soil resources. These findings are important because this knowledge can be useful in formulating pasture and forest management strategies. IGPS is a powerful method to assist in study of the spatial relationships between plants and soil resources, and we recommend that this method be used worldwide. © 2017 Elsevier B.V.

Li S.-X.,Beijing Forestry University | Li M.-F.,Beijing Forestry University | Yu P.,Beijing Forestry University | Fan Y.-M.,Beijing Forestry University | And 2 more authors.
Bioresource Technology | Year: 2017

A novel pretreatment process was developed to achieve valorization of bamboo components into digestible cellulose, degraded sugars and lignin. In this case, bamboo was pretreated with 60% γ-valerolactone (GVL)/40% water containing 0.05 mol/L H2SO4, yielding solid fraction rich in cellulose. The resulting liquor was further treated with the addition of NaCl and ultrasound, resulting in water phase rich in degraded sugars and GVL phase containing lignin, which was easy to recover. Results showed that the enzymatic hydrolysis was enhanced by 6.7-fold after treatment as compared to the control. The degraded sugars released in water phase contained monosaccharides (70.72–160.47 g/kg) together with oligo- and polysaccharides (46.4–181.85 g/kg). The lignin obtained had high purity, low molecular weight (1820–2970 g mol−1) and low polydispersity (1.93–1.98). The present study creates a novel pretreatment process for the conversion of Gramineae biomass into useful feedstocks with potential applications in the fields of fuels, chemicals and polymers. © 2017 Elsevier Ltd

Qin Y.,Beijing Forestry University | Xin Z.,Beijing Forestry University | Wang D.,Beijing Forestry University | Xiao Y.,Beijing Forestry University
Catena | Year: 2017

Riparian woodlands have recently been recognized as important carbon (C) storage regions with a considerable potential of sequestering C to mitigate global warming. Understanding soil organic carbon (SOC) storage in riparian woodland and the differences in SOC storage between riparian woodlands and other adjacent land types is important to effectively assess SOC storage in riparian woodlands and the influences of riparian land-use changes on SOC pool. Therefore, we thoroughly investigated C storage in the riparian woodlands along the Lijiang River watershed, located in a karst area in southwestern China. The goals of the study were to quantify the SOC density (SOCD) in the riparian woodland (0–20 cm depth of upper soil) [N = 54, the plot area was 1130.88 ± 136.13 m2 (mean value with standard deviation)]; to compare the differences in SOCD in the riparian woodland [bamboo-dominated (N = 9) and non-bamboo-dominated woodlands (N = 45)], the adjacent grasslands (N = 13) and the farmlands [croplands (N = 17) and orchards (N = 17)]; and to assess the influence of soil texture, plant litter and soil root biomass on the SOCD of the riparian woodlands. The results showed that the average SOCD in the riparian woodlands of the Lijiang River watershed was 35.79 ± 9.51 t/ha. The SOCD in the non-bamboo-dominated woodland was 36.91 ± 9.63 t/ha, which was higher than that in the bamboo-dominated woodlands (29.86 ± 4.90 t/ha) by 7.05 t/ha (about 23.59%) (p < 0.05) and was higher than that in the adjacent grasslands (27.77 ± 7.35 t/ha), croplands (28.93 ± 7.30 t/ha) and orchards (21.26 ± 8.20 t/ha) by 32.91%, 27.58% and 73.61%, respectively (p < 0.01). However, the SOCD in the bamboo-dominated woodlands was only higher than that in the orchard by 8.60 t/ha (about 40.45%) (p = 0.012). In the non-bamboo-dominated woodlands in the Lijiang riparian watershed, the SOCD showed a significant negative correlation with soil sand content (r = − 0.69) and a significant positive correlation with the silt (r = 0.59) and clay content (r = 0.61) (p < 0.01). The SOCD showed a significant positive correlation with plant litter (r = 0.44) and soil root biomass (r = 0.38) (p < 0.05). Finally, the results indicate that the non-bamboo-dominated riparian woodland in the karst area stores more SOC compared with the adjacent grassland and farmland. However, converting riparian vegetation into bamboo woodland did not increase the accumulation of SOC and even caused some SOC loss in the Lijiang riparian area. © 2017

Huang J.,Beijing Forestry University | Liu W.,Beijing Forestry University | Shi Z.,Beijing Jiaotong University
Construction and Building Materials | Year: 2017

A layered periodic structure is proposed to construct a periodic wave barrier, which is defined by extended typical cells consisting of two different components. The periodic structure with reasonable design has attenuation zones (AZs) which can block wave propagation. The surface-wave dispersion curves and material/geometric parameters of layered periodic structures were investigated using finite element method. A typical three-dimensional simulation model was applied to verify the efficiency of the proposed periodic wave barrier in terms of ground vibration isolation. The results showed that simulated frequency zones of vibration reduction are consistent with the theoretical surface-wave AZs, and that periodic wave barriers can greatly reduce train-induced vibrations. © 2017 Elsevier Ltd

Cao S.,Minzu University of China | Zheng X.,Beijing Forestry University | Chen L.,Minzu University of China | Ma H.,Nanning Water Conservancy Bureau | Xia J.,Beijing Normal University
Agronomy for Sustainable Development | Year: 2017

People who live in ecologically fragile environments face both poverty and environmental degradation, which reinforce each other and create a “poverty trap.” Traditional ecological restoration projects focus only on ecological measures, and thus ignore the livelihoods of local residents. Those projects therefore fail to solve the poverty trap. In addition, project subsidies to residents typically end when the projects end, thus forcing residents to return to their old way of life and reversing the gains from the projects. To break this cycle, we performed a study in China’s Yanan City, in Shaanxi Province, to promote a new “green purchase” method for implementing sustainable economic activities that bring residents ongoing earnings without harming the environment. This method involves the construction of terraced fields, establishment of fruit tree orchards, implementation of grazing restrictions, and ecological migration. We found that the method was ecologically effective, as it increased Yanan’s vegetation cover by 0.89% annually since 1999, which is twice the rate for Shaanxi Province. © 2017, INRA and Springer-Verlag France.

Zhu Y.,Beijing Forestry University | Kan J.,Beijing Forestry University | Xu D.,Beijing Forestry University
UPB Scientific Bulletin, Series D: Mechanical Engineering | Year: 2017

Carrying equipment into a forest is a difficult taskfor the common vehicle chassisbecause of the complex terrain conditions,which directly restrictsthe development of mechanization in the forestsof southern China. In the present study, the design requirements for avehicle chassisare analyzed according to the geomorphic conditions in the forestsof southern China. Aforestry chassis with an articulated body with three degrees of freedomis proposed. The performance when negotiating obstaclesis enhanced by the articulated structure of chassisbecause the structure canachieve yawing, rolling,and pitchingmotion between the front and rearframesand the chassis can adapt to the complex variation of terrains timely and automatically.Furthermore, thewheels are also optimized by proposing a new method of maximizing the traction force and minimizing the sinkage. The results of the calculationof the turning radius, lateral stability and longitudinal stability indicate that this newlydesigned chassiscould meet the requirementsof the design well and adapt to the complicated roads in the forests of southern China.

Luo L.,Beijing Forestry University | Liu W.,Beijing Forestry University | Xu S.-L.,Zhejiang University | Ren Y.-Y.,Beijing Forestry University
Gongcheng Lixue/Engineering Mechanics | Year: 2017

The damage propagation property of Ultra-high toughness cementitious composites (UHTCC) was studied using three-point flexural fatigue tests on single-notched specimens. Based on the continuum damage mechanics and the flexural fatigue damage model, two fatigue damage propagation models were built. One was a bi-logarithmic linear model with J-integral range as its independent variable. The other was a semi-logarithmic linear model with fatigue stress level as its independent variable. Results from the two models fit well with experimental results. However, because the J-integral is strongly dependent on the specimens' geometry, the first model was affected significantly by the specimens' shape. The second model is expected to be more applicable in engineering practice since the fatigue stress level is easy to obtain. © 2017, Engineering Mechanics Press. All right reserved.

Yu J.,Beijing Forestry University | Xu W.,East Stroudsburg University | Rogers M.,East Stroudsburg University
Journal of Computational and Theoretical Nanoscience | Year: 2017

Teamwork skills have becoming an important asset that employees can bring into an organization. How to make employees work with other team members and make team effective is an important issue in business education. In order to make sense which factors in team management will help improve team performance, we try to design a test among students. In this paper, we focus on using 12-step method to help business students acquire their teamwork skills and improve their team performance in class, and propose and examine several hypotheses on the relationship between 12-step and their impact on team performance with a dataset collecting from university student teams. The results show that initial sharing, continuous sharing and feedbacks are positively associated with team performance, but expectation, equity and celebration are negatively associated with team performance. The findings provide some insights about how to apply different steps in different environments, and show that some measures and steps should be paid more attention in training in a firm or other organizations. Copyright © 2017 American Scientific Publishers.

Wang L.,Beijing Forestry University | Dumont R.S.,McMaster University | Dickson J.M.,McMaster University
Molecular Physics | Year: 2017

A NEMD simulation system is constructed to simulate at two-dimensional (2D) periodic boundary conditions (PBCs) and to create two different pressures on two sides of the carbon nanotube (CNT) membrane. The simulation results show that water permeation through the same CNT membrane driven by different pressure differences exhibit similar transport phenomenon including unusually fast water permeation and a periodic (non-parabolic) radial velocity distribution unlike the parabolic form characteristic of continuum flow in the CNT membrane. A three-dimensional (3D) PBC system is also constructed to simulate water permeation through the same CNT membrane at the same pressure differences, to show the effect of PBC and simulation methodologies on transport phenomenon. The two systems both show that the forward/backward water flux increases/decreases with increasing the pressure difference from 1.0 MPa to 8.0 MPa. However, the net flux is higher for the 3D PBC system, especially at higher pressure difference is high. In general, the NEMD simulation method using the 2D PBC system is shown to be a feasible and valuable tool for studying pressure-driven permeation processes such as nanofiltration through these studies with model CNT membrane. © 2017 Informa UK Limited, trading as Taylor & Francis Group.

Wang C.-J.,Beijing Forestry University | Wan J.-Z.,Beijing Forestry University | Zhang Z.-X.,Beijing Forestry University
Scandinavian Journal of Forest Research | Year: 2017

Climate change may increase expansion risk of invasive tree plants (ITPs) worldwide. Ecoregions are the power conservation tool for the management of ITPs. However, few studies have investigated the relationship between ITP expansion and ecoregions at the global scale under climate change scenarios. Here, we provided a method to evaluate the expansion potential of 54 representative ITPs in ecoregions specifically under influences of the changing climate at the global scale. We found that climate change due to increasing greenhouse gas (GHG) concentration plays a positive role on the expansion of ITPs. We determined two of the most important ecoregion hotspots of ITP expansion potential, such as New Zealand and South Africa. In addition, ITPs were likely to have a large potential to expand in ecoregions of five different biomes, like temperate broadleaf and mixed forests. The potential expansion of ITPs would increase obviously in ecoregions of Boreal Forests/Taiga and Tundra. More importantly, the ecoregions of high elevation belonging to Tropical and Subtropical Coniferous Forests were expected to experience the higher expansion risk in the low GHG concentration scenario. Given our estimates of ITP expansion for ecoregions, management for the prevention and control for ITPs is urgent at the global scale. © 2017 Informa UK Limited, trading as Taylor & Francis Group

Zhang Y.,Beijing Forestry University | Huang K.,Beijing Forestry University | Yu Y.,Beijing Institute of Technology | Yang B.,Beijing Forestry University
Journal of Cleaner Production | Year: 2017

A bibliometric analysis of the research in the field of Water Footprint (WF) during 2006–2015 was presented with the information related to countries, institutions, journals, categories, top cited publications, keywords, hot issues and research trends. Researches on WF have increased sharply over the past decade. The United States (24.1%), China (19.2%) and Netherlands (16.0%) had high productivity in total publications. Based on co-word and social network analysis (SNA), the USA-China has been most closely correlated in the cooperative web system. University of Twente took the leading position of institutions in total articles and also conducted the most independent, collaborative, first authored, and corresponding authored articles. Journal of Cleaner Production, Environmental Science & Technology and Ecological Indicators are the top three journals with the most publications in this field. A summary of the most frequently used keywords obtained from title, author keywords and keywords plus analysis provided the clues to discover the current research emphases. The mainstream research related to WF was its accounting methodologies and application in water resource management. Water-food-energy nexus, driving mechanism of WF variation, environmental impact of water use and integration of footprint indicators strongly promoted the development of WF research and are getting popular in recent years. Findings provide a better understanding of characteristics of WF research which serves as a useful reference for future studies. © 2017 Elsevier Ltd

Chu D.,Beijing Forestry University | Mu J.,Beijing Forestry University | Zhang L.,Beijing Forestry University | Li Y.,Beijing Forestry University
Holzforschung | Year: 2017

Heat treatment (HT) enhances various properties of wood (W), but it takes a relatively long time and WHT is a source of fire hazard. To improve the properties of WHT, Populus beijingensis W. Y. Hsu wood was impregnated with nitrogen-phosphorus (NP) fire retardant (10% aqueous solution) and the effects of the combined NP treatment and HT were observed. Control groups included native wood and samples from WHT200°C,120min and WHT220°C,120min. The surface color, dimensional stability, and combustion properties of the treated samples were examined. NP pre-treatment intensified the effectivity of HT150°C, where the treatment time decreased by 75%. The decomposition and catalytic dehydration of NP treatment enhanced the dimensional stability and darkened the wood surface. After HT, the NP fire retardant was transformed from dispersive particles into a uniform layer on the inner surfaces of wood. The heat release rate (HRR) decreased by 60.3% and the residual mass (RM) increased by 61.1% in WNP, HT compared to normal WHT200°C poplar.

Yang J.,Beijing Forestry University | Xu F.,Beijing Forestry University | Han C.-R.,Beijing Forestry University
Biomacromolecules | Year: 2017

Utilization of reversible interactions as sacrificial bonds in biopolymers is critical for the integral synthesis of mechanically superior biological materials. In this work, cellulose nanofibrils (CNFs) reinforced covalent polyacrylamide (PAAm) composite hydrogels are immersed into multivalent cation (Ca2+, Zn2+, Al3+, and Ce3+) aqueous solution to form ionic association among CNFs, leading to the ionic-covalent cross-linked hydrogels. The cations promote the formation of porous networks of nanofibrils by screening the repulsive negative charges on CNF surface and dominate the mechanical properties and self-recovery efficiency of the hydrogels, resulting in mechanically reinforced ionic hydrogels with stiff (Young's modulus 257 kPa) and tough properties (fracture toughness 386 kJ/m3). The in situ Raman spectroscopy during stretching corroborates the stress transfer medium of CNF, and the microscopic morphologies of stable crack propagation validates that the multiple toughening mechanisms occur in a balanced energy dissipation manner, enabling synergistic combination of stiffness and toughness. Moreover, the depth-sensing instrumentation by indentation test also demonstrates that the CNF ionic coordination contributes simultaneous improvement in hardness and elasticity by as much as 600% compared to those pristine gels. This work demonstrates a facile way to transfer nanoscale building blocks to bulk elastomers with tunable dynamic properties and may provide a new prospect for the rational design of CNF reinforced hydrogels for applications where high-bearing capability is needed. © 2017 American Chemical Society.

Zhao J.,Beijing Forestry University
RISTI - Revista Iberica de Sistemas e Tecnologias de Informacao | Year: 2016

Cloud computing has changed the modern education model. Any educational institutions can share teaching experience through the global online learning resources based on unlimited network resources. By collecting the data generated by the learners in the process of network learning, we construct a learning analysis system based on the distributed Hadoop based on cloud computing technology. Application of cloud computing and big data analysis of online education platform, companies can improve service content, improve the quality of personalized service, while achieving tracking services, precision services, knowledge related services.

Chen Y.-Y.,Beijing Forestry University | Wu F.,Beijing Forestry University | Wang M.,Beijing Forestry University | Cui B.-K.,Beijing Forestry University
Mycological Progress | Year: 2017

In this study, phylogenetic analysis of Fibroporia and its related genera was carried out based on multiple loci of ITS, nLSU, nSSU, mtSSU, tef1 and rpb2. Combined with the morphological characters, a new genus, Pseudofibroporia gen. nov., is established. Phylogenetically, Pseudofibroporia is closely related to Fibroporia, but morphologically, the former is different from the latter in its distinct pileate basidiomata with entire margin and lacking rhizomorphs. In addition, three new species, Fibroporia bambusae sp. nov., F. ceracea sp. nov. and Pseudofibroporia citrinella sp. nov., are described from China. Fibroporia bambusae is different from other species by its cream to pinkish buff pore surface, cinnamon buff rhizomorphs and a dimitic hyphal system with both clamped and simple-septate generative hyphae. F. ceracea is distinguished by its ceraceous pore surface and a monomitic hyphal system with clamped generative hyphae. Pseudofibroporia citrinella is characterized by white to lemon yellow pileal surface, lemon yellow to curry buff pores, a dimitic hyphal system with clamped generative hyphae and oblong to broadly ellipsoid, and slightly thick-walled basidiospores (4–4.5 × 2.2–2.8 μm). Illustrated descriptions of the novel species and a key to known species of Fibroporia from China are provided. © 2017 German Mycological Society and Springer-Verlag Berlin Heidelberg

Mei X.,Beijing Forestry University | Mei X.,Xinjiang University | Shen Y.,Beijing Forestry University
Journal of Forestry Research | Year: 2017

Nitraria sibirica Pall. is a shrub that grows in saline-alkali soil and has traditional medicinal value and potential commercial value. The objectives of this study include induction and multiplication of callus, establishment of a suspension cell line, and isolation of protoplasts from cell suspensions. Murashige and Skoog (MS) medium was used for callus induction from mature seeds of N. sibirica. Seed-derived calluses were further multiplied on MS medium augmented with 0.5 mg L−1 6-benzylaminopurine (6-BA) and 1.0 mg L−1 2,4-dichlorophenoxy (2,4-D) acetic acid. Suspension cultures of N. sibirica were initiated by transferring friable calli to the same liquid multiplication medium. Characterization of the suspension culture was assessed based on fresh mass, dry mass, cell viability and pH value of the culture. A typical growth curve was observed after inoculating 1.5 g of callus in 40 mL liquid medium, including a lag phase, an exponential growth phase, a stationary phase, and a negative acceleration phase. The effect of factors such as pre-plasmolysis, enzyme combination, enzymolysis time and mannitol concentration, on the isolation of cell-derived protoplasts were evaluated to determine the usefulness of suspension cultures. The maximum yield (9.79 × 106 cells/g) and highest viability (79.97%) of protoplast were reached when approximately 1 g of cell suspension (cultured for 6 days) was inoculated for 12 h in cell and protoplast washing solution made of 0.8 mol L−1 mannitol mixture solution, cellulose onozuka R-10 2% (w/v), hemicellulose 0.2%, macerozyme R-10 1%, and pectolyase Y-23 0.5%. Protoplast yield was significantly influenced by pre-plasmolysis and cellulose onozuka R-10 (P < 0.05). © 2017 Northeast Forestry University and Springer-Verlag Berlin Heidelberg

Yang W.,Beijing Forestry University | Qi W.,Beijing Twenty first Century Science and Technology Development Co. | Wang M.,Beijing Normal University | Zhang J.,Beijing Forestry University | Zhang Y.,Beijing Forestry University
Geomorphology | Year: 2017

Major earthquakes in mountain regions have persistent and significant influences on post-seismic landslides but their details have not been well understood. This work uses multi-year high-resolution satellite images and terrain parameters, such as elevation, slope, and aspect, to examine the topographic changes of post-seismic landslides. Despite disturbances during rainy months, landslide areas decreased significantly from 2008 to 2013 in all terrain parameters, indicating that landslide activity near the epicentre has been recovering to the pre-seismic level. The emergence of an increasingly active landslide type shows that landslide debris has been moving from hillslopes to valleys, which could impact post-seismic debris flows. The findings of this work provide important information for post-seismic infrastructure re-construction and disaster prevention in future mountain earthquake events. © 2016 Elsevier B.V.

Song X.,Beijing Forestry University | Shi Q.,Beijing Forestry University | Wang H.,Beijing Forestry University | Liu S.,Beijing Forestry University | And 2 more authors.
Applied Catalysis B: Environmental | Year: 2017

A convenient method based on photocatalytic reduction was used to prepare graphene-supported Pd, Fe, and bimetallic Pd-Fe nanoparticle (NP) catalysts under mild conditions. The obtained catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Their potential application to the electrocatalytic degradation of chlorinated phenols (CPs) was investigated by cyclic voltammetry (CV) and chronoamperometry. The graphene-supported bimetallic Pd-Fe NP catalyst (Pd0.5Fe0.5/graphene) exhibited the optimal surface performance and contained highly abundant and widespread Pd-Fe NPs of approximately 6.75 ± 0.05 nm in size. It exhibited higher electrocatalytic activity for dechlorination of CPs attributed to its higher hydrogen adsorption peak current of 0.117 mA than that of the Pd/graphene catalyst, with a 1% weight ratio of Pd (Pd1.0/graphene catalyst), and the Fe/graphene catalyst, with a 1% weight ratio of Fe (Fe1.0/graphene catalyst). The highest reductive peak current (0.038 mA) was obtained at -0.347 V when using the Pd0.5Fe0.5/graphene catalyst, indicating that the Pd0.5Fe0.5/graphene catalyst has the highest electrocatalytic activity for accelerating the two-electron reduction of O2 to H2O2. In addition, the electrocatalytic activity was enhanced when feeding with O2 and at pH 12.8. The electrochemical reductive reaction of O2 is typically a diffusion-controlled electrochemical process. The calculated values of k representing the mass transfer rate were in the order Pd0.5Fe0.5/graphene (0.379) > Pd1.0/graphene (0.178) > Fe1.0/graphene (0.175). The reduction peak currents for four CPs decreased in the order 3-chlorophenol (0.0214 mA) > 2,4,5-trichlorophenol (0.0190 mA) > 2,4-dichlorophenol (0.0188 mA) > 4-chlorophenol (0.0178 mA), indicating that the Pd0.5Fe0.5/graphene electrode would show the most powerful indirect electro-oxidation for 3-CP degradation in comparison with the other CPs. Therefore, the Pd0.5Fe0.5/graphene catalyst exhibits a higher electrocatalytic activity than the Pd1.0/graphene catalyst and Fe1.0/graphene catalyst for the reductive dechlorination and indirect electrochemical oxidation of CPs. © 2016 Elsevier B.V. All rights reserved.

Geng Y.,Beijing Forestry University | Wang D.,Beijing Forestry University | Yang W.,Beijing Forestry University
Catena | Year: 2017

The most important environmental processes in riparian zones are the release of carbon, nitrogen, and phosphorus from various organic compounds. The extracellular enzymes of soil microorganisms are involved in the biogeochemical cycling of organic matter nutrients and may be important for regulating water quality. The objectives of the present study were to determine whether the activities of soil enzymes were affected by different inundation periods in the riparian zone and to identify major factors that influence soil enzyme activity. We subjected three study plots to different inundation conditions (long inundation, moderate inundation, and rare inundation) within the transects perpendicular to the river flow at three sites (Weijiadu, Lijiaocun, and Daxu) in Lijiang, Guilin City, China. Soil physicochemical properties, dissolved nutrient composition, and soil enzyme activities were analyzed. The activity of acid phosphatase, alkaline phosphatase, and arylsulfatase significantly increased as the inundation frequency decreased, whereas the activity of glucosidase, β-N-acetylglucosaminidase, glycine aminopeptidase, L-leucine aminopeptidase, and dehydrogenase were significantly higher in study plots that received long inundation than in those subjected to moderate or rare inundation. Linear regression indicated that most hydrolase and dehydrogenase activities were affected by soil clay content, soil organic matter, and soil water content, among other factors. NO3 −-N limited the activity of acid phosphatase, L-leucine aminopeptidase, and glycine aminopeptidase. Polyphenol oxidase activity was constrained by soil water content and available potassium but promoted by NO3 −-N. Our study demonstrated that imposing longer inundation periods can increase soil enzyme activities. To maintain microbial activity and to minimize water pollution, it is important to reduce high NO3 −-N loads. © 2016 Elsevier B.V.

Yan Q.,Beijing Forestry University | Fang Y.C.,Beijing Forestry University | Jia Y.X.,Beijing Forestry University | Duan X.H.,Beijing Forestry University
New Journal of Chemistry | Year: 2017

Hydrogen peroxide oxidation of primary alcohols to aldehydes is described, which is catalyzed by a novel, reusable and water-soluble FeCl3 complex in situ-formed with quaternary ammonium salt-functionalized 8-aminoquinoline. This reaction exhibits unique chemoselectivity and broad functional-group tolerance, and it can operate efficiently in pure water at room temperature. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Wang P.,Beijing Forestry University | Chen G.Q.,Peking University
International Journal of Heat and Mass Transfer | Year: 2017

Taylor dispersion with wall absorption in a laminar tube flow is analytically studied in this work by Aris's method of concentration moments. The difficulty associated with the conventional approach initiated by Sankarasubramanian and Gill is completely avoided. All the basic characteristic properties governing the dispersion process, including the exchange rate, advection velocity, dispersivity, skewness and kurtosis, are analytically determined in their full time dependance for the first time. Detailed parametrical analysis is performed for the properties. Mean concentration distribution is concretely characterized. © 2017 Elsevier Ltd

Dahal D.S.,Beijing Forestry University | Dahal D.S.,CAS Institute of Tibetan Plateau Research | Cao S.,Beijing Forestry University
Proceedings of the National Academy of Sciences India Section B - Biological Sciences | Year: 2017

Nepal’s Community Forestry Program is a sustainable forest management and livelihood enhancement program reformed from earlier programs of the previous century. The government’s initial policy was to provide the basic forest resources to local communities through their active participation in forest improvement and management. Nepal’s policy and development program was based on sustainability concepts. Community forestry can be sustainable and produce socially, economically, and ecologically beneficial results. A number of both qualitative and quantitative options have been applied to measure the sustainable use of forests and other natural resources in community forests, but classifying the results is challenging. Policy-makers, experts, and the communities should be involved in developing and improving criteria and indicators for community forest management, reflecting the diversity of perspectives that must be accounted for and the increasing worldwide demand for sustainability and governance. The main findings were that sustainability can be measured with numerous tools, but there are several challenges. A literature review revealed that nationally and internationally defined criteria and indicators have not been extensively applied in Nepal due to lack of technical and other expertise. © 2015, The National Academy of Sciences, India.

Wang P.,Beijing Forestry University | Wang P.,University of Massachusetts Amherst | Alpert P.,University of Massachusetts Amherst | Yu F.-H.,Beijing Forestry University
Folia Geobotanica | Year: 2017

Most work on clonal growth in plants has focused on the advantages of clonality in heterogeneous habitats. We hypothesized (1) that physiological integration of connected ramets within a clone can also increase plant performance in homogeneous environments, (2) that this effect depends on whether ramets differ in ability to take up resources, and (3) that only ramets with relatively low uptake ability benefit. We tested these hypotheses using the perennial amphibious herb Alternanthera philoxeroides. We grew clonal fragments and varied numbers of rooted versus unrooted ramets, connection between the apical and basal parts of fragments, and availability of nitrogen. Patterns of final size and mass of fragments did not support these hypotheses. By some measures, severance did reduce the growth of more apical ramets and increase the growth of less apical ones, consistent with net apical transfer of resources. Rooting of individual ramets strongly influenced their growth: second and third most apical ramets each grew most when they were the most apical rooted ramet, and this pattern was more pronounced under higher nitrogen levels. This adds to the evidence that signalling between ramets is an important aspect of clonal integration. Overall, the results indicate that physiological integration between ramets within clones in homogeneous environments can alter the allocation of resources between connected ramets even when it does not affect the total growth of clonal fragments. © 2017 Institute of Botany, Academy of Sciences of the Czech Republic

Wang H.,Beijing Forestry University | Wu X.,Beijing Institute of Technology | Jia Y.,Beijing Institute of Technology
IET Computer Vision | Year: 2017

In this study, the authors study the video annotation problem over heterogeneous domains, in which data from the image source domain and the video target domain is represented by heterogeneous features with different dimensions and physical meanings. A novel feature learning method, called heterogeneous discriminative analysis of canonical correlation (HDCC), is proposed to discover a common feature subspace in which heterogeneous features can be compared. The HDCC utilises discriminative information from the source domain as well as topology information from the target domain to learn two different projection matrices. By using these two matrices, heterogeneous data can be projected onto a common subspace and different features can be compared. They additionally design a group weighting learning framework for multi-domain adaptation to effectively leverage knowledge learned from the source domain. Under this framework, source domain images are organised in groups according to their semantic meanings, and different weights are assigned to these groups according to their relevancies to the target domain videos. Extensive experiments on the Columbia Consumer Video and Kodak datasets demonstrate the effectiveness of their HDCC and group weighting methods. © The Institution of Engineering and Technology.

Fan Y.,Beijing Forestry University | Sun J.,Beijing Forestry University
Mechanika | Year: 2017

As a key factor for the safety of electric vehicles, electric vehicles are focused on battery pack stability rather than vehicle dynamics. The stability of battery pack depends on the performance of suspensions and battery sup-porting system. Automobile suspensions can reduce the bumps and vibrations that come from road unevenness. Its purposes are to prevent the shock and vibration from transferring to the body, and reduce the vibration of the battery pack. To improve the performance of suspension systems of the electric vehicle and the stability of battery pack, the paper proposes a study on the interaction of electric vehicle roll and battery pack stability. 9-DOF vehicle vibration and roll model was established based on analysis of movement of the battery pack. Then simulation model was established to check the result to get the reasonable suspension stiffness by using Matlab/Simulink. The results show that the stiffness of the suspension is increased by configuring a high performance shock absorber and a short spring. Although it will inhibit roll, simply increasing the hardness of the shock absorber and the spring will cause a lot of negative effects.

Huang Q.,Beijing Normal University | Yang X.,Brown University | Yang X.,The Ecosystems Center | Gao B.,Beijing Normal University | And 2 more authors.
Remote Sensing | Year: 2014

Since the release of the digital archives of Defense Meteorological Satellite Program Operational Line Scanner (DMSP/OLS) nighttime light data in 1992, a variety of datasets based on this database have been produced and applied to monitor and analyze human activities and natural phenomena. However, differences among these datasets and how they have been applied may potentially confuse researchers working with these data. In this paper, we review the ways in which data from DMSP/OLS nighttime light images have been applied over the past two decades, focusing on differences in data processing, research trends, and the methods used among the different application areas. Five main datasets extracted from this database have led to many studies in various research areas over the last 20 years, and each dataset has its own strengths and limitations. The number of publications based on this database and the diversity of authors and institutions involved have shown promising growth. In addition, researchers have accumulated vast experience retrieving data on the spatial and temporal dynamics of settlement, demographics, and socioeconomic parameters, which are "hotspot" applications in this field. Researchers continue to develop novel ways to extract more information from the DMSP/OLS database and apply the data to interdisciplinary research topics. We believe that DMSP/OLS nighttime light data will play an important role in monitoring and analyzing human activities and natural phenomena from space in the future, particularly over the long term. A transparent platform that encourages data sharing, communication, and discussion of extraction methods and synthesis activities will benefit researchers as well as public and political stakeholders. © 2014 by the authors.

Liu J.,Beijing Forestry University | Liu J.,International Institute For Applied Systems Analysis | Folberth C.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Yang H.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | And 4 more authors.
PLoS ONE | Year: 2013

Food security and water scarcity have become two major concerns for future human's sustainable development, particularly in the context of climate change. Here we present a comprehensive assessment of climate change impacts on the production and water use of major cereal crops on a global scale with a spatial resolution of 30 arc-minutes for the 2030s (short term) and the 2090s (long term), respectively. Our findings show that impact uncertainties are higher on larger spatial scales (e.g., global and continental) but lower on smaller spatial scales (e.g., national and grid cell). Such patterns allow decision makers and investors to take adaptive measures without being puzzled by a highly uncertain future at the global level. Short-term gains in crop production from climate change are projected for many regions, particularly in African countries, but the gains will mostly vanish and turn to losses in the long run. Irrigation dependence in crop production is projected to increase in general. However, several water poor regions will rely less heavily on irrigation, conducive to alleviating regional water scarcity. The heterogeneity of spatial patterns and the non-linearity of temporal changes of the impacts call for site-specific adaptive measures with perspectives of reducing short- and long-term risks of future food and water security. © 2013 Liu et al.

Wang P.,Beijing Forestry University | Chen G.Q.,Peking University
Journal of Hydrology | Year: 2016

Reactive solute dispersion is of essential significance in various ecological and environmental applications. It is only qualitatively known that boundary absorption depletes pollutant around the boundary and reduces the concentration nearby. All the existing studies on this topic have been focused on the longitudinally distributed mean concentration, far from enough to fully characterize the transport process with tremendous cross-sectional concentration nonuniformity. This work presents an analytical study of the evolution of two-dimensional concentration distribution for solute dispersion in a laminar open channel flow with bed absorption. The fourth order Aris-Gill expansion proposed in our previous study (Wang and Chen, 2016b) is further extended for the case with bed absorption to cover the transitional effects of skewness and kurtosis. Results reveal the extremely nonuniform cross-sectional concentration distribution, and demonstrate that concentration at the bed instead of the mean should be used for reliable quantification of the absorption flux. The accurate two-dimensional concentration distribution presented in this study brings important environmental implications such as risk assessment associated with peak concentration position and duration of toxic pollutant cloud in open channel waters. © 2016 Elsevier B.V.

Miao C.Y.,Beijing Normal University | Yang L.,CAS Institute of Geographical Sciences and Natural Resources Research | Chen X.H.,University of Nebraska - Lincoln | Gao Y.,Beijing Forestry University
Land Degradation and Development | Year: 2012

Vegetation significantly influences human health in the Yellow River basin and the plant cover is vulnerable to people. Typical types of erosion in the Yellow River basin include that caused by water, wind and freeze-thaw. In this paper, vegetation cover change from 1982 to 2006 was studied for a number of different erosion regions. The Global Inventory Monitoring and Modeling Studies Normalized Difference Vegetation Index (GIMMS NDVI) data were employed, while climatic data were also used for analysis of other influencing factors. It was shown that: (1) generally the vegetation cover in different erosion regions displayed similar increasing trends; (2) spatially the vegetation cover was highest in the water erosion region, the second highest was in the freeze-thaw region and the lowest in the wind erosion region; and (3) vegetation cover in the Yellow River basin is influenced by climate factors, especially by temperature. In water erosion regions, the temporal change of vegetation cover seemed complicated by comprehensive climatic and human influences. In wind erosion regions, the vegetation cover had close relations to precipitation. In freeze-thaw erosion regions, the vegetation cover was primarily altered by temperature. In all the three erosion regions, significant change of the vegetation cover occurred from 2000 just after the 'Grain for Green' (GFG) programme was implemented throughout China. © 2010 John Wiley & Sons, Ltd.

Jiang J.,Nanjing Forestry University | Jiang J.,Beijing Forestry University
Journal of Reinforced Plastics and Composites | Year: 2016

Based on the anatomical and chemical properties, a representative volume unit was studied to predict the longitudinal elastic modulus of bamboo (Phyllostachys glauca McClure). Microstructure features and chemical characterization of bamboo were obtained. Elastic constant of cell wall in length was derived by the application of rule of mixture. Taking advantage of the representative volume unit model, the longitudinal elastic modulus prediction formula of bamboo was established, and the theoretical and experimental value were calculated. The results showed that modified formula was acceptable to predict the longitudinal elastic modulus value with the error rate between predicted and experimental values below 25%. It is feasible to simplify the microstructure to calculate the longitudinal elastic modulus by model. © SAGE Publications.

Liu Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Liu Y.,Beijing Normal University | Lu S.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Lu S.,Beijing Forestry University | Chen Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
Journal of Rural Studies | Year: 2013

The urban-rural equalized development is not only significant theoretically, but also a strategic challenge facing the coordinated development of urban and rural China. In this paper we put forward an innovative theory of URED against the background of China's urban-rural transformation. The spatio-temporal pattern, its change and driving factors of urban-rural equalized development during 1996-2009 were analyzed using principal component analysis, the Markov chain model and exploratory spatial data analysis model based on the data for 31 Chinese provinces (autonomous regions and municipalities). It is found that during the study period URED exhibited an obvious tendency of "club homogenization" in China. However, since 2003 the homogenization of the URED for entire China has weakened. Moreover, URED showed a significant geographic characteristic of "polarization" during 1996-2003. Namely, the spatial units of a high URED level were concentrated in eastern China near the coast, and the spatial units of a low URED level were located mainly in central and western China. However, this spatial polarized structure of URED was destroyed since 2003, and the spatial disparity at the provincial level has decreased. Finally, it is concluded that policies and institutional structure, economic growth and urbanization were the main driving factors of the identified URED spatio-temporal pattern and its change in China. This study may serve as a scientific reference regarding decision-making in coordinating urban and rural development and in constructing the new countryside of China. © 2013 Elsevier Ltd.

Shi S.,Beijing Forestry University | Cao J.,Beijing Forestry University | Feng L.,Beijing Forestry University | Liang W.,Beijing Forestry University | Zhang L.,Beijing Forestry University
Journal of Hazardous Materials | Year: 2014

The environmental pollution resulting from chemical accidents has caused increasingly serious concerns. Therefore, it is very important to be able to determine in advance the appropriate emergency treatment and disposal technology for different types of chemical accidents. However, the formulation of an emergency plan for chemical pollution accidents is considerably difficult due to the substantial uncertainty and complexity of such accidents. This paper explains how the event tree method was used to create 54 different scenarios for chemical pollution accidents, based on the polluted medium, dangerous characteristics and properties of chemicals involved. For each type of chemical accident, feasible emergency treatment and disposal technology schemes were established, considering the areas of pollution source control, pollutant non-proliferation, contaminant elimination and waste disposal. Meanwhile, in order to obtain the optimum emergency disposal technology schemes as soon as the chemical pollution accident occurs from the plan repository, the technique evaluation index system was developed based on group decision-improved analytical hierarchy process (AHP), and has been tested by using a sudden aniline pollution accident that occurred in a river in December 2012. © 2014 Elsevier B.V.

Du F.K.,Beijing Forestry University | Xu F.,Beijing Forestry University | Qu H.,Peking University | Feng S.,Beijing Forestry University | And 2 more authors.
PLoS ONE | Year: 2013

Background:Microsatellite markers or Simple Sequence Repeats (SSRs) are the most popular markers in population/conservation genetics. However, the development of novel microsatellite markers has been impeded by high costs, a lack of available sequence data and technical difficulties. New species-specific microsatellite markers were required to investigate the evolutionary history of the Euphratica tree, Populus euphratica, the only tree species found in the desert regions of Western China and adjacent Central Asian countries.Methodology/Principal Findings:A total of 94,090 non-redundant Expressed Sequence Tags (ESTs) from P. euphratica comprising around 63 Mb of sequence data were searched for SSRs. 4,202 SSRs were found in 3,839 ESTs, with 311 ESTs containing multiple SSRs. The most common motif types were trinucleotides (37%) and hexanucleotides (33%) repeats. We developed primer pairs for all of the identified EST-SSRs (eSSRs) and selected 673 of these pairs at random for further validation. 575 pairs (85%) gave successful amplification, of which, 464 (80.7%) were polymorphic in six to 24 individuals from natural populations across Northern China. We also tested the transferability of the polymorphic eSSRs to nine other Populus species. In addition, to facilitate the use of these new eSSR markers by other researchers, we mapped them onto Populus trichocarpa scaffolds in silico and compiled our data into a web-based database ( Conclusions:The large set of validated eSSRs identified in this work will have many potential applications in studies on P. euphratica and other poplar species, in fields such as population genetics, comparative genomics, linkage mapping, QTL, and marker-assisted breeding. Their use will be facilitated by their incorporation into a user-friendly web-based database.

Yuan J.-h.,Beijing Forestry University | Yuan J.-h.,CAS Institute of Botany | Yuan J.-h.,Gansu Forestry Technological College | Cheng F.-Y.,Beijing Forestry University | And 2 more authors.
PLoS ONE | Year: 2012

Background: Tree peonies are great ornamental plants associated with a rich ethnobotanical history in Chinese culture and have recently been used as an evolutionary model. The Qinling Mountains represent a significant geographic barrier in Asia, dividing mainland China into northern (temperate) and southern (semi-tropical) regions; however, their flora has not been well analyzed. In this study, the genetic differentiation and genetic structure of Paeonia rockii and the role of the Qinling Mountains as a barrier that has driven intraspecific fragmentation were evaluated using 14 microsatellite markers. Methodology/Principal Findings: Twenty wild populations were sampled from the distributional range of P. rockii. Significant population differentiation was suggested (F ST value of 0.302). Moderate genetic diversity at the population level (H S of 0.516) and high population diversity at the species level (H T of 0.749) were detected. Significant excess homozygosity (F IS of 0.076) and recent population bottlenecks were detected in three populations. Bayesian clusters, population genetic trees and principal coordinate analysis all classified the P. rockii populations into three genetic groups and one admixed Wenxian population. An isolation-by-distance model for P. rockii was suggested by Mantel tests (r = 0.6074, P<0.001) and supported by AMOVA (P<0.001), revealing a significant molecular variance among the groups (11.32%) and their populations (21.22%). These data support the five geographic boundaries surrounding the Qinling Mountains and adjacent areas that were detected with Monmonier's maximum-difference algorithm. Conclusions/Significance: Our data suggest that the current genetic structure of P. rockii has resulted from the fragmentation of a formerly continuously distributed large population following the restriction of gene flow between populations of this species by the Qinling Mountains. This study provides a fundamental genetic profile for the conservation and responsible exploitation of the extant germplasm of this species and for improving the genetic basis for breeding its cultivars. © 2012 Yuan et al.

Riely B.K.,University of California at Davis | He H.,University of California at Davis | Venkateshwaran M.,University of Wisconsin - Madison | Sarma B.,Banaras Hindu University | And 3 more authors.
Plant Journal | Year: 2011

Summary Root hairs play important roles in the interaction of plants with their environment. Root hairs anchor the plant in the soil, facilitate nutrient uptake from the rhizosphere, and participate in symbiotic plant-microbe interactions. These specialized cells grow in a polar fashion which gives rise to their elongated shape, a process mediated in part by a family of small GTPases known as Rops. RopGEFs (GEF, guanine nucleotide exchange factor) activate Rops to effect tip growth in Arabidopsis pollen and root hairs, but the genes mediating tip growth in legumes have not yet been characterized. In this report we describe the Rop and RopGEF gene families from the model legume Medicago truncatula and from the crop legume soybean. We find that one member of the M. truncatula gene family, MtRopGEF2, is required for root hair development because silencing this gene by RNA interference affects the cytosolic Ca 2+ gradient and subcellular structure of root hairs, and reduces root hair growth. Consistent with its role in polar growth, we find that a GFP::MtRopGEF2 fusion protein localizes in the apex of emerging and actively growing root hairs. The amino terminus of MtRopGEF2 regulates its ability to interact with MtRops in yeast, and regulates its biological activity in vivo. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

Fan L.,Beijing Forestry University | Fan L.,CAS Institute of Botany | Li R.,Beijing Forestry University | Pan J.,Zhejiang Normal University | And 2 more authors.
Trends in Plant Science | Year: 2015

Endocytosis provides a major route of entry for membrane proteins, lipids, and extracellular molecules into the cell. Recent evidence indicates that multiple cellular processes require endocytosis, including nutrient uptake, signaling transduction, and plant-microbe interactions. Also, advanced microscopy, combined with biochemical and genetic approaches, has provided more insights into the molecular machinery and functions of endocytosis in plants. Here we review mechanisms of the clathrin-dependent and membrane microdomain-associated endocytic routes in plant cells. In addition, degradation of endocytosed proteins and endosomal sorting complex required for transport (ESCRT)-mediated vesicle formation at the endosome are discussed. Finally, we summarize the essential roles of various regulators during plant endocytosis. © 2015 Elsevier Ltd.

Du X.,CAS Institute of Process Engineering | Zhao W.,CAS Institute of Process Engineering | Wang Y.,CAS Institute of Process Engineering | Wang C.,Tianjin University of Technology | And 4 more authors.
Bioresource Technology | Year: 2013

Activated carbon hollow fibers (ACHFs) with high surface area were prepared from inexpensive, renewable ramie fibers (RFs) by a single-step activation method under lower temperature than that of other reports. The effects of activation conditions on the pore structure and turbostratic structure of ACHFs were investigated systematically. The results show that ACHFs surface area decreased but micropore volume and conductivity increased as the increase of activation temperature and activation time. The electrochemical measurements of supercapacitors fabricated from these ACHFs electrodes reveal that the electrochemical properties improved with the enhancing of activation degree. However, too high activation temperature can make the ion diffusion resistance increase. It suggests that pore structure and conductivity are as important as surface area to decide the electrochemical performances of ACHFs electrode materials. A maximum capacity of 287Fg-1 at 50mAg-1 was obtained for the ACHFs electrode prepared under suitable conditions. © 2013 Elsevier Ltd.

Jiang X.,Beijing Forestry University | Gong P.,Swedish University of Agricultural Sciences | Bostedt G.,Swedish University of Agricultural Sciences | Xu J.,Peking University
Environment and Development Economics | Year: 2014

State-owned forest enterprises (SOFEs) in northeast China play important roles both in timber production and in the maintenance of ecological security. This paper examines the effects of a number of policy measures on the behavioral choices of the SOFEs. The results show that the extent to which SOFE supervising authorities emphasized the improvement of forest resources in their annual evaluation of the SOFEs had significant impacts on the harvest and investment decisions and the development of forest resources. Promotion of the management and utilization of non-timber resources, as well as reforms aiming to increase the efficiency of forest protection and management, reduced timber harvests and increased investment, which in turn led to improvements of forest resources, although the effects were small. In contrast, reforms aimed at timber harvest and afforestation activities actually contributed to increasing timber harvest, which affected the development of the forest resources negatively. © 2013 Cambridge University Press.

Que Z.-L.,Nanjing Forestry University | Que Z.-L.,Kyoto University | Wang F.-B.,Nanjing Forestry University | Li J.-Z.,Beijing Forestry University | Furuno T.,The University of Shimane
Composites Part B: Engineering | Year: 2013

This paper assesses the reproducibility of testing formaldehyde and VOCs (volatile organic compounds) emissions from wood-based composites such as MDF (medium density fiberboard), hardboard, plywood, coated and raw particleboards, planed pine lumber, and gypsum board. Sawdust and shavings were also included in the study. With the help of a special device, air was sucked from the surfaces of the materials and then was adsorbed on charcoal and Tenax tubes. The adsorbed VOCs were determined by gas chromatography/mass spectrometry. The emission of formaldehyde was determined separately with Interscan Toxic Gas analyzer and chamber method. The results showed that the most emitted VOCs were terpenes, aldehydes, and aromatics. Pine wood plank revealed the highest VOCs (approximately 900 μg/m3). Fresh particleboard showed the second highest value with 450 μg/m3. The VOC value of other examined materials were 80-170 μg/m3. The composition of the emitted compounds was remarkably similar among the different materials. The low VOC emission from the board materials investigated did not verify the hypothesis that these materials provided a tangible contribution to VOCs in the indoor air. Emission of formaldehyde from the board materials studied was very low with an exception. The exception was MDF with an emission value of 0.63 mg/m3 formaldehyde whereas all the other materials examined had values around 0.05 mg/m3 or appreciably lower. © 2013 Elsevier Ltd. All rights reserved.

Wang X.,Beijing Forestry University | Wang X.,Peking University | Ouyang S.,Beijing Forestry University | Sun O.J.,Beijing Forestry University | Fang J.,Peking University
Forest Ecology and Management | Year: 2013

The emergency of satellite-borne light detecting and ranging (LiDAR) technology in recent years have provided a promising way to monitor worldwide patterns of forest biomass and carbon sources/sinks. However, few studies have examined the roles of various abiotic and biotic factors in modulating the relationship between forest biomass and height at a large scale. This is important given the growing dependence on LiDAR derived forest height as a predictor of forest biomass. In this analysis, we used 529plots across northeast China to examine this question, and to explore the method to estimate forest biomass from height. Our results showed that, while forest height and average tree height showed close relationships with stand biomass or mean biomass per stem (R2 between 0.57 and 0.78), stand biomass could not be reliably predicted with two methods based on average tree height. In contrast, when the effects of climate and forest groups were included in the models, forest height could predict biomass patterns with a R2 between 0.74 (belowground) and 0.91 (total biomass), which was comparable to the widely accepted biomass expansion factor method (R2 between 0.72 and 0.98). We also showed that the ratio of both aboveground and belowground biomass to forest height (B/H ratio) was roughly similar at a large scale, suggesting that forest biomass patterns are strongly shaped by forest height. However, B/H ratio showed significant difference between deciduous and evergreen forests across northeast China. The life form of canopy trees was the major factor modulating the relationships between stand biomass and forest height, while climate, forest type and forest origin played a secondary role. Our results strongly support the use of LiDAR to monitor the large-sale patterns of both above and belowground forest biomass. Our analysis also found that the lack of forest height information in previous literatures has caused most of the biomass data could not be utilized to estimate biomass patterns from height, and we advocate future analyses to report forest height together with field-observed biomass. © 2013 Elsevier B.V.

The relative effects of climate and geometric constraints on geographic diversity patterns have long been controversial. We developed a new method to assess the role of geometric constraints in shaping altitudinal richness patterns. We showed how plant species richness on four mountains in southwest China are shaped by geometric constraints and environmental gradients together. Contrary to previous studies, our results suggested that: 1) small- and large-ranged species richness were largely controlled by the same environmental gradients, and differed mainly in the effect of geometric constraints. 2) The contribution of geometric constraints (in addition to environmental gradients) to explaining species richness was greater when species richness peaked at low altitudes than at mid-altitudes, suggesting that geometric constraints may be very important when richness peaks are far away from mid-domains. 3) Relating species richness directly to environmental factors (the most widely used method in biodiversity studies) may be misleading when geometric constraints may be affecting the richness pattern, because this method may overestimate the effect of environmental factors by failing to distinguish the confounding effect of geometric constraints. Instead, the effect of environmental factors can be evaluated with an underlying gradient derived from small-ranged species. 4) The geometric constraints effect cannot be fully evaluated by pure geometric constraints models, and is better evaluated with range-based models constrained with environmental gradients. 5) If the generality of our findings is supported for other taxa on other gradients, then many previous studies on the effects of climate and of geometric constraints on geographic diversity patterns may need to be re-visited. © 2012 The Authors. Ecography © 2012 Nordic Society Oikos.

Xin Z.,Beijing Forestry University | Yu X.,Beijing Forestry University | Li Q.,Beijing Forestry University | Lu X.X.,National University of Singapore
Regional Environmental Change | Year: 2011

Water resources and soil erosion are the most important environmental concerns on the Chinese Loess Plateau, where soil erosion and sediment yield are closely related to rainfall erosivity. Daily rainfall data from 60 meteorological stations were used to investigate the spatiotemporal variations in annual rainfall, annual erosive rainfall and annual rainfall erosivity on the Chinese Loess Plateau during the period 1956-2008. The annual rainfall, erosive rainfall and rainfall erosivity decreased over the past five decades, as determined by the Mann-Kendall test. A comparison of the annual averaged rainfall, erosive rainfall and rainfall erosivity from 1980 to 2008 with that from 1956 to 1979 revealed a remarkable spatial difference in the rainfall trends on the Loess Plateau. Regions of the plateau with major decreases in rainfall were primarily in the Hekouzhen-Longmen section of the middle Yellow River, especially in the Wuding River basin, the Fenhe basin and the northern-central Shanxi province, where the annual rainfall and erosive rainfall decreased by more than 10% and the annual rainfall erosivity decreased by more than 15%. The rainfall erosivity also decreased more than the annual rainfall. Because the annual rainfall has decreased significantly on the Chinese Loess Plateau over the past 50 years, it is important to better understand the ecological and hydrological processes affected by this climate change. © 2010 Springer-Verlag.

Shi Q.,Beijing Forestry University | Wang H.,Beijing Forestry University | Liua S.,Beijing Forestry University | Bian Z.,Beijing Normal University
RSC Advances | Year: 2014

Palladium-modified graphene gas-diffusion cathodes were prepared using Pd/graphene catalysts and characterized using cyclic voltammetry, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy and Fourier transform infrared spectrometry. The Pd particles were amorphous and had an average size of 5.4 nm, and were highly dispersed in the graphene. A diaphragm electrolysis system sequentially fed with H2 and air over the gas-diffusion cathodes was constructed, and applied to the degradation of 2,4-dichlorophenol (2,4-DCP). When the Pd/graphene gas-diffusion cathode was fed with hydrogen, reductive dechlorination of 2,4-DCP took place, whereas acceleration of two-electron reduction of O2 to H2O2 proceeded in air. Dechlorination of 2,4-DCP reached approximately 96.4% after 60 min, while its removal efficiency and its removal in terms of total organic carbon (TOC) reached approximately 100% and 90.5%, respectively, after 120 min. By analysis of the electrolysis products by HPLC and IC, a reaction pathway has been proposed for the degradation of 2,4-DCP. © The Royal Society of Chemistry 2014.

Liu J.,Beijing Forestry University | Liu J.,International Institute For Applied Systems Analysis | Yang H.,Eawag - Swiss Federal Institute of Aquatic Science and Technology
Journal of Hydrology | Year: 2010

An accurate estimate of global water uses with high spatial resolution is a key to assessing global water scarcity and to understanding human's interference with the ecosystems. In spite of the progress made previously, there is a lack of spatially explicit assessment of both green and blue water uses in agriculture. In this paper, we estimated consumptive water use (CWU) in cropland on a global scale with a spatial resolution of 30 arc-minutes. A GIS-based version of the EPIC model, GEPIC, is used for the estimation. The results show that in crop growing periods, global CWU was 5938 km3 a-1 in cropland around the year 2000, of which green water contributed to 84%. On an annual basis, global CWU was 7323 km3 a-1 in cropland, of which green water contributed to 87%. We compared the simulated consumptive blue water use (CBWU) with the statistical CBWU at the national level among individual countries, and at the federal state or province level in the USA and China. The comparison indicates a good agreement between the simulated and statistical CBWU, suggesting a satisfactory performance of the GEPIC model and reliability of the estimation in irrigated cropland. The importance of green water in both crop production and food trade calls for a better management of green water, in addition to blue water. © 2009 Elsevier B.V. All rights reserved.

Wang P.,Beijing Forestry University | Wang P.,Peking University | Chen G.Q.,Peking University
Journal of Hydrology | Year: 2016

Closely related to the solar photocycle, plankton growth in eutrophic waters displays a diurnal variation because of photosynthesis and respiration. Presented in this paper is an analytical study of the diurnal variation of mean concentration of plankton and nutrient in an open channel eutrophic flow initiated by an instantaneous emission. The evolution of the concentration is shown driven by the combination of hydraulic dispersion and diurnal reaction between plankton and nutrient. The analytical solution for longitudinal distribution of concentration is rigorously derived and illustrated, based on the time dependent hydraulic dispersivity. Numerical results are presented and characterized by the reaction rate, yield factor and period for the diurnal reaction and the P. éclet number of the flow. For typical applications such as ecological risk assessment and environmental impact assessment, the upper and lower limits of critical length and duration of five typical pollutant concentrations are concretely illustrated for given concentration criterions. Remarkable diurnal variations are revealed up to around one third in the critical length and duration for plankton, and about ten percent for nutrient. © 2016 Elsevier B.V.

Ren L.,Beijing Forestry University | Shi J.,Beijing Forestry University | Luo Y.,Beijing Forestry University
Micron | Year: 2012

The parasitoid beetle Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is an important parasite of longicorn beetles (Cerambycidae), and has been used in China for the biological control of the Asian longicorn beetle and the Japanese pine sawyer. In this study the antennal morphology and sensillar ultrastructure of D. helophoroides were observed using scanning electron microscopy and transmission electron microscopy. Two types of sensilla trichodea (Tr. 1 and Tr. 2), two types of sensilla basiconica (Ba. 1 and Ba. 2), three types of sensilla chaetica (Ch. 1, Ch. 2 and Ch. 3), and Bohm's bristles were identified according to the morphology and fine structure of each type of sensilla in both sexes. Ultrastructural studies revealed porous structures on the cuticle wall and dendritic branches in the inner lumen of Tr. 1, Tr. 2, Ba. 1, and Ba. 2, thereby suggesting chemoreceptor functions. No difference in shape, structure, sensilla distribution and typology was observed between the sexes. These structures likely have roles in the host locating and habitat searching behavior of adult D. helophoroides, and suggest future studies on the olfaction and host location behavior of D. helophoroides and other coleopteran parasitoids. © 2012 Elsevier Ltd.

Liu J.,Beijing Forestry University | Liu J.,International Institute For Applied Systems Analysis | You L.,International Food Policy Research Institute | Amini M.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | And 4 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2010

Crop production is the single largest cause of human alteration of the global nitrogen cycle. We present a comprehensive assessment of global nitrogen flows in cropland for the year 2000 with a spatial resolution of 5 arc-minutes. We calculated a total nitrogen input (IN) of 136.60 trillion grams (Tg) of N per year, of which almost half is contributed by mineral nitrogen fertilizers, and a total nitrogen output (OUT) of 148.14 Tg of N per year, of which 55% is uptake by harvested crops and crop residues. We present high-resolution maps quantifying the spatial distribution of nitrogen IN and OUT flows, soil nitrogen balance, and surface nitrogen balance. The high-resolution data are aggregated at the national level on a per capita basis to assess nitrogen stress levels. The results show that almost 80% of African countries are confronted with nitrogen scarcity or nitrogen stress problems, which, along with poverty, cause food insecurity and malnutrition. The assessment also shows a global average nitrogen recovery rate of 59%, indicating that nearly two-fifths of nitrogen inputs are lost in ecosystems. More effective management of nitrogen is essential to reduce the deleterious environmental consequences.

Liu J.,Beijing Forestry University | Liu J.,International Institute For Applied Systems Analysis | Zang C.,Beijing Forestry University | Tian S.,Beijing Forestry University | And 7 more authors.
Global Environmental Change | Year: 2013

China's water policies in the past decades have relied heavily on the construction of massive water conservancy projects in the form of dams and reservoirs, water transfer projects, and irrigation infrastructure. These facilities have brought tremendous economic and social benefits but also posed many adverse impacts on the eco-environment and society. With the intensification of water scarcity, China's future water conservancy development is facing tremendous challenge of supporting the continuous economic development while protecting the water resources and the dependent ecosystems. This paper provides an overview of China's water conservancy development, and illustrates the socioeconomic, environmental and ecological impacts. A narrative of attitude changes of the central government towards water conservancy, as well as key measures since the 1950s is presented. The strategic water resources management plan set by the central government in its Document No. 1 of 2011 is elaborated with focus on the three stringent controlling " redlines" concerning national water use, water use efficiency and water pollution and the huge investments poised to finance their implementation. We emphasize that realizing the goals set in the strategic plan requires paradigm shifts of the water conservancy development towards maximizing economic and natural capitals, prioritizing investment to preserve intact ecosystems and to restore degraded ecosystems, adapting climate change, balancing construction of new water projects and rejuvenation of existing projects, and managing both " blue" (surface/groundwater) and " green" water (soil water). © 2013 Elsevier Ltd.

Xin Z.,Beijing Forestry University | Ran L.,National University of Singapore | Lu X.X.,National University of Singapore
International Journal of Water Resources Development | Year: 2012

The sediment load of the Loess Plateau has shown a sharp decreasing trend in the past decades. This paper gives a comprehensive review of the driving factors of the sediment decrease with respect to human activities, including soil and water conservation, dam construction, and vegetation restoration. Also presented is an overview of the main achievements of soil and water conservation and the main soil erosion control programmes implemented in the Loess Plateau. The paper concludes with suggestions for further policy modifications that could move management towards ecological sustainability and will be greatly beneficial to the regional water resources management and restoration of an eco-environmental system in the Loess Plateau. © 2012 Copyright Taylor and Francis Group, LLC.

Yuan J.-H.,Beijing Forestry University | Yuan J.-H.,Gansu Forestry Technological College | Cheng F.-Y.,Beijing Forestry University | Cheng F.-Y.,National Flower Engineering Research Center | Zhou S.-L.,CAS Institute of Botany
International Journal of Plant Sciences | Year: 2010

In Paeonia, hybridization is an important path for both the development of new cultivars and species formation in nature, but the characterization of hybrids has long been a problem. To establish the relationship among Paeonia yananensis, P. jishanensis, and P. rockii, we sampled 159 individuals from 11 populations around the core population of P. yananensis. Samples were subjected to morphological analysis of 22 characters and molecular analysis of three chloroplastDNA(cpDNA) fragments and 14 microsatellites. Paeonia yananensis was distinguishable from the other two species on the basis of morphological characteristics. The phylogenetic tree based on three intergenic spacers in the chloroplast genome (petB-petD, rps16-trnQ, and psbA-trnH) demonstrated that P. yananensis was very closely related to P. jishanensis. However, analysis of 14 microsatellite loci revealed that P. yananensis shared a considerable number of alleles with both P. jishanensis and P. rockii. These results demonstrated that P. yananensis (P × 3 yananensis) is of hybrid origin, with P. jishanensis as a maternal parent and P. rockii as a paternal parent. Our success in documenting the hybrid origin of P. yananensis suggests that combined evidence from morphology, maternally inherited cpDNA, and biparentally inherited microsatellites could serve as a powerful tool in hybrid studies. © 2010 by The University of Chicago. All rights reserved.

Fang C.L.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Guan X.L.,National Academy for Mayors of China | Lu S.S.,Beijing Forestry University | Zhou M.,Peking University | Deng Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
Urban Studies | Year: 2013

Urban agglomerations (UAs) in China play a vital role in the distribution of productive forces and constitute the most dynamic and potentially rich core areas for future economic development. However, the rapid economic growth and high-intensity interactions seen in relation to these areas, results of the high population densities and aggregation of industries in UAs, also pose significant ecological threats to the environment. This paper attempts to analyse changing trends in the input-output efficiency of UAs in China based on the data envelopment analysis (DEA) approach. The paper investigates the DEA efficiency of UAs with different population sizes and geographical locations, explores the relationship between the elements that make up a decomposed model of efficiency and compares the efficiency performance of China's UAs with that of 35 central cities. Moreover, the exogenous factors determining the input-output efficiency of UAs, the question of how to improve UAs' efficiency performance, as well as the focus of future research are also discussed. A number of valuable implications have been drawn from the study, which may be helpful to the task of understanding more deeply the high-density aggregation effects of UAs in China. © 2013 Urban Studies Journal Limited.

Xu J.,Beijing Forestry University | Zhang Z.,Beijing Normal University | Liu W.,Beijing Forestry University | McGowan P.J.K.,Northumbria University
ORYX | Year: 2012

Abstract There were 2,541 nature reserves accounting for c. 15% of China's land territory by 2009. As nature reserves hold the majority of the country's wildlife they play a fundamental role in protecting the country's biodiversity. National policies relevant to nature reserves have had a positive effect on biodiversity although these policies are now facing increasing challenges. We reviewed the development of relevant policy and legislation and identify and assess challenges, using a questionnaire survey and personal interviews. The main challenges identified and assessed included lack of harmonization between government departments, between nature reserves and other protected area designations, and between nature reserves and local communities. In addition, recent transfers of responsibilities between government entities, potential impacts of forest tenure reforms, and issues surrounding natural resource use and ecotourism were identified. These obstacles could undermine the achievements of biodiversity conservation in China if they are not addressed soon. Given these findings, we make recommendations to guide future policy formulation in relation to nature reserve management and development. © 2012 Fauna & Flora International.

Zhang C.,Beijing Forestry University | Zhao X.,Beijing Forestry University | Gadow K.V.,University of Gottingen | Gadow K.V.,Stellenbosch University
Forest Ecology and Management | Year: 2014

This study presents an analysis of selective harvest events in three 10-ha field plots with mapped trees, representing different forest successional stages in the temperate multi-species forests of North-Eastern China. Non-spatial methods of analyzing the harvest events include species and size selection preference and an assessment of harvest intensities for four species groups (identified using bivariate mixed dbh/height distributions). Spatial aggregation increased very slightly after the harvest event, but in most cases, the change was hardly noticeable. In addition, tree selection preferences involving nearest neighbor structure units are presented, using the attributes "species mingling" and "dominance". The removals occurred within a broad array of neighborhood constellations, involving suppressed as well as dominant individuals. Previous approaches involving harvest event analysis in multi-species forests were limited to assessing size and species selection preferences. This study uses more advanced methods and presents more detailed interpretations, due to the large and detailed observational datasets and improved analytical tools that have become available recently. Models of tree growth and survival, which represent the overwhelming result of traditional observational studies, only describe a part of forest dynamics. Equally important are the modifications caused by regular human disturbance. There is thus increasing motivation for analyzing selective harvesting activities as presented in this contribution. © 2013 Elsevier B.V.

Chan J.M.W.,University of California at Berkeley | Chan J.M.W.,Energy Biosciences Institute EBI | Chan J.M.W.,IBM | Bauer S.,Energy Biosciences Institute EBI | And 7 more authors.
ACS Catalysis | Year: 2013

Lignin samples isolated from Miscanthus giganteus using organosolv processes were treated with vanadium catalysts that were previously developed in our group. We demonstrate that the catalyst with high β-O-4′ bond-cleaving activity in dimeric lignin models was also effective in depolymerizing actual lignin. Molecular weight-lowering was evidenced by gel permeation chromatography (GPC), whereas 2D NMR experiments showed that β-O-4′ linkages were selectively cleaved in the degradation process, just as in the case of lignin models. Monophenolic degradation products were also formed, and the individual molecules were identified and quantified by GC/MS. © 2013 American Chemical Society.

Ke C.,Beijing Forestry University | Li Z.,Tsinghua University | Liang Y.,Beijing Forestry University | Tao W.,Forestry Protection Station of Beijing | Du M.,Beijing Forestry University
Applied Soil Ecology | Year: 2013

This study was conducted to investigate the dynamic changes of bulk soil and microbial populations in the surrounding plant rhizosphere under the influence of chloride de-icing salt. Each experimental plant was given 0.25L de-icing salt solution with an irrigation concentration of 200g/L, once every 3 days for 27 days. Samples were taken weekly from each soil layers (0-15cm, 15-30cm and 30-45cm). The results revealed that de-icing salt led to different effects in different soil layers in one month. A trend of increasing electric conductivity (EC) values, Na+ concentrations, and Cl- concentrations in the upper soil layer, compared with the other two soil layers, was apparent, which proved a stronger effect of de-icing salt on the upper soil layer. Soil cation exchange capacity (CEC) decreased with the accumulation of the de-icing salt. Denaturing gradient gel electrophoresis (DGGE) analysis indicated that de-icing salt decreased the Shannon diversity (H) and Evenness (E) of fungal populations in three soil layers and led to a decrease of bacterial H in the upper soil layers. However, a contrary trend for H and E of bacterial populations was seen in the middle and lower soil layers. Both the unweighted pair group mean average (UPGMA) cluster and canonical correspondence analysis (CCA) analysis indicated that the bacterial populations were more stable than the fungal populations in response to salinity stress. CCA analysis showed the dynamic changes of microbial populations and the soil properties (EC, CEC, Na+ and Cl-) were strongly correlative. The microbial populations were obtaining a new dynamic equilibrium at the end of the study. The dominant microbial populations were originally Crepidotus, Metarhizium, Penicillium and Acidobacterium, but converted to Pythium, Boletaceae, Cystofilobasidiales, Phacidium, Acidobacterium, Pseudomonas and Chloroflexi with the addition of de-icing salt. The obtained results suggest that the uses of chemical agents leading to soil salinization, such as de-icing salt, can destroy the micro-ecosystem of bulk soil surrounding plant rhizosphere and influence soil health. © 2013 Elsevier B.V.

Li X.,Beijing Forestry University | Li X.,CAS Institute of Botany | Luu D.-T.,French National Institute for Agricultural Research | Maurel C.,French National Institute for Agricultural Research | And 2 more authors.
Trends in Plant Science | Year: 2013

The plant plasma membrane is highly dynamic and changes multiple aspects of its organization in response to environmental and internal factors. A detailed understanding of membrane dynamics in living plant cells has remained obscure because of the limited spatial resolution of conventional optical microscopy. Recently, several single-molecule imaging approaches have been developed and used to provide valuable insights into the fundamental biochemical and biophysical properties of the plant plasma membrane, including the organization of membrane microdomains and the dynamics of single-molecule diffusion. Here we review single-molecule imaging methods, including total internal reflection fluorescence microscopy (TIRFM), fluorescence correlation spectroscopy (FCS), and super-resolution microscopy, and examine their contributions to recent progress in understanding protein dynamics and membrane organization in living plant cells. © 2013 Elsevier Ltd.

He Q.,Nanjing Forestry University | Berg A.,Pennsylvania State University | Li Y.,West Virginia University | Vallejos C.E.,University of Florida | And 3 more authors.
Trends in Genetics | Year: 2010

One of the fundamental tasks in biology is the identification of genes that control the structure and developmental pattern of complex traits and their responses to the environment during trait development. Functional mapping provides a statistical means for detecting quantitative trait loci (QTLs) that underlie developmental traits, such as growth trajectories, and for testing the interplay between gene action and development. Here we describe how functional mapping and studies of plant ontology can be integrated so as to elucidate the expression mechanisms of QTLs that control plant growth, morphology, development, and adaptation to changing environments. This approach can also be used to construct an evo-devo framework for inferring the evolution of developmental traits. © 2009 Elsevier Ltd. All rights reserved.

Walawage S.L.,University of California at Davis | Britton M.T.,University of California at Davis | Leslie C.A.,University of California at Davis | Uratsu S.L.,University of California at Davis | And 2 more authors.
BMC Genomics | Year: 2013

Background: Crown gall (CG) (Agrobacterium tumefaciens) and the root lesion nematodes (RLNs) (Pratylenchus vulnus) are major challenges faced by the California walnut industry, reducing productivity and increasing the cost of establishing and maintaining orchards. Current nematode control strategies include nematicides, crop rotation, and tolerant cultivars, but these methods have limits. Developing genetic resistance through novel approaches like RNA interference (RNAi) can address these problems. RNAi-mediated silencing of CG disease in walnut (Juglans regia L.) has been achieved previously. We sought to place both CG and nematode resistance into a single walnut rootstock genotype using co-transformation to stack the resistance genes. A. tumefaciens, carrying self-complimentary iaaM and ipt transgenes, and Agrobacterium rhizogenes, carrying a self-complimentary Pv010 gene from P. vulnus, were used as co-transformation vectors. RolABC genes were introduced by the resident T-DNA in the A. rhizogenes Ri-plasmid used as a vector for plant transformation. Pv010 and Pv194 (transgenic control) genes were also transferred separately using A. tumefaciens. To test for resistance, transformed walnut roots were challenged with P. vulnus and microshoots were challenged with a virulent strain of A. tumefaciens. Results: Combining the two bacterial strains at a 1:1 rather than 1:3 ratio increased the co-transformation efficiency. Although complete immunity to nematode infection was not observed, transgenic lines yielded up to 79% fewer nematodes per root following in vitro co-culture than untransformed controls. Transgenic line 33-3-1 exhibited complete crown gall control and 32% fewer nematodes. The transgenic plants had thicker, longer roots than untransformed controls possibly due to insertion of rolABC genes. When the Pv010 gene was present in roots with or without rolABC genes there was partial or complete control of RLNs. Transformation using only one vector showed 100% control in some lines. Conclusions: CG and nematode resistance gene stacking controlled CG and RLNs simultaneously in walnuts. Silencing genes encoding iaaM, ipt, and Pv010 decrease CG formation and RLNs populations in walnut. Beneficial plant genotype and phenotype changes are caused by co-transformation using A. tumefaciens and A. rhizogenes strains. Viable resistance against root lesion nematodes in walnut plants may be accomplished in the future using this gene stacking technology. © 2013 Walawage et al.; licensee BioMed Central Ltd.

Huang H.,Beijing Forestry University | Cao B.,Beijing Normal University
Proceedings - 2011 8th International Conference on Fuzzy Systems and Knowledge Discovery, FSKD 2011 | Year: 2011

Taking advantage of rational polynomial coefficient (RPC) data delivered along with the very high resolution satellite (VHRS) Worldview-2 images, we proposed an easy RPC adjustment method for the commercial software ENVI to generate digital surface model (DSM) with only one ground control point (GCP). The DSM was then used to derive canopy crown height (CHM) and forest stand height. The experiment was performed in North-east Beijing and evaluated by the measured tree height at a flat plot and other hillside plots. The flat plot was a ceremony garden in urban areas, and the hill plots distributed within a small mountain. The RMSE of the differences between estimation and field results was 1.5m. This research demonstrates that Worldview-2 has the ability to model and derive forest stand height under relative sparse conditions. © 2011 IEEE.

Liu C.,Beijing Forestry University | Wang H.,Beijing Forestry University | Zhu Y.,Beijing Normal University | Niu H.,Renmin University of China
Advances in Information Sciences and Service Sciences | Year: 2012

With the outstanding of economic and environmental conflicts, issues between them are increasingly becoming the focus of the world. This paper used the directional distance function to measure Chinese industry environmental technical efficiency during 2001-2008, and it used the efficiency to evaluate the coordination of environment, energy and industrial growth. It found that Chinese environment, energy and industrial growth in a more coordinated state, but there is still some energy saving and emission reduction space from static perspective and dynamic perspective. Through trend analysis, the technical efficiency of Chinese environment in recent years had been an upward trend, "the 11th Five-Year Development Guidelines" had achieved remarkable results; static and dynamic analysis, coordination gap between the industry was relatively large.

Hao H.,CAS Institute of Botany | Fan L.,CAS Institute of Botany | Chen T.,CAS Institute of Botany | Li R.,CAS Institute of Botany | And 7 more authors.
Plant Cell | Year: 2014

Arabidopsis thaliana respiratory burst oxidase homolog D (RbohD) functions as an essential regulator of reactive oxygen species (ROS). However, our understanding of the regulation of RbohD remains limited. By variable-angle total internal reflection fluorescence microscopy, we demonstrate that green fluorescent protein (GFP)-RbohD organizes into dynamic spots at the plasma membrane. These RbohD spots have heterogeneous diffusion coefficients and oligomerization states, as measured by photobleaching techniques. Stimulation with ionomycin and calyculin A, which activate the ROS-producing enzymatic activity of RbohD, increases the diffusion and oligomerization of RbohD. Abscisic acid and flg22 treatments also increase the diffusion coefficient and clustering of GFP-RbohD. Single-particle analysis in clathrin heavy chain2 mutants and a Flotillin1 artificial microRNA line demonstrated that clathrin-and microdomain-dependent endocytic pathways cooperatively regulate RbohD dynamics. Under salt stress, GFP-RbohD assembles into clusters and then internalizes into the cytoplasm. Dual-color fluorescence cross-correlation spectroscopy analysis further showed that salt stress stimulates RbohD endocytosis via membrane microdomains. We demonstrate that microdomain-associated RbohD spots diffuse at the membrane with high heterogeneity, and these dynamics closely relate to RbohD activity. Our results provide insight into the regulation of RbohD activity by clustering and endocytosis, which facilitate the activation of redox signaling pathways. © 2014 American Society of Plant Biologists. All rights reserved.

Zhuge C.,Beijing Forestry University | Sun X.,Beijing University of Posts and Telecommunications | Chen Y.,Peking University | Lei J.,Tsinghua University
Journal of Theoretical Biology | Year: 2016

The tumor suppressor p53 plays a central role in cell fate decisions after DNA damage. Programmed Cell Death 5 (PDCD5) interacts with the p53 pathway to promote cell apoptosis. Recombinant human PDCD5 can significantly sensitize different cancers to chemotherapies. In the present paper, we construct a computational model that includes PDCD5 interactions in the p53 signaling network and study the effects of PDCD5 on p53-mediated cell fate decisions during the DNA damage response. Our results revealed that PDCD5 functions as a co-activator of p53 and regulates p53-dependent cell fate decisions via the mediation of p53 dynamics. The effects of PDCD5 are dose-dependent, such that p53 activity exhibits sustained low level, pulsed oscillations, or sustained high level dynamics depending on the PDCD5 level following DNA damage. Moreover, PDCD5 regulates caspase-3 activation via two mechanisms during the two phases of sustained and pulsed p53 dynamics. This study provides insights regarding how PDCD5 functions as a regulator of the p53 pathway and might be helpful for increasing our understanding of the molecular mechanisms by which PDCD5 can be used to treat cancers. © 2015 Elsevier Ltd.

Ran L.,National University of Singapore | Lu X.X.,National University of Singapore | Lu X.X.,Inner Mongolia University | Xin Z.,Beijing Forestry University | Yang X.,National University of Singapore
Global and Planetary Change | Year: 2013

Reservoir sedimentation has been a serious problem for reservoir operation and watershed management worldwide, which highlights the importance of accurate estimate of the deposited sediment amount. With reservoir information derived from remote sensing dataset and observed hydrological records of water and sediment, this paper is concerned with the cumulative reservoir sediment trapping in the Yellow River basin. The river basin was divided into 12 sub-basins, upon which the reservoirs' sediment trapping efficiency (TE) and their interception effects on inflowing sediment were estimated with sediment records extracted from 179 field sampling stations. The results show that, with the sediment TE greater than 80% for all the sub-basins, theoretically the basin-wide reservoirs are able to trap most sediment. For the whole river basin, the sediment TE averages 95.2%, which indicates that the reservoirs can collectively make a significant anthropogenic signature on basin-wide sediment delivery. A basin-wide sediment yield map was generated to estimate the reservoir sedimentation amount. During 1950-1970, annually about 2.483. Gt of sediment was transported into channels from sloping lands. Taking into account the actual water storage changes and the reservoir construction history, the actual reservoir sedimentation rate was estimated at 0.59. Gt/yr after corrections, which represents 47.6% of the river basin's total sediment load reduction. Globally, reservoir sedimentation in the Yellow River basin represents about 12-15% of the global mean rate. Up to 2010, approximately 19.32. Gt of sediment has been trapped by Yellow River reservoirs, and totally about 40.32. Gt of sediment has been artificially fixed if silt check dams are also considered. With huge amounts of sediment deposited, these reservoirs have been losing their storage capacity to sedimentation at a rate of 0.6% per year. The magnitude is expected to enhance in future following new reservoir completions. Thus, more efforts are strongly needed to explore the associated responses. © 2012 Elsevier B.V.

Wu X.,Beijing Forestry University | Cai Y.,Peking University | Zhou T.,Beijing Forestry University
Energy Procedia | Year: 2011

Based on extraction of environmental information from lake (reservoir) sediment, this paper carried out systematic studies on effects of land use/land cover changes on soil erosion in last 40 years in Shibanqiao catchment of Guanling County, located in the southwest of Guizhou Province. Seven sediment cores were retrieved and analysis of activity of 137Cs of sediment samples was undertaken. The information of soil erosion in each phase was deduced, and then integrating it with land use/land cover changes in corresponded phase, the author took a further step to interpret the effects of land use/land cover changes on soil erosion. Such conclusions were drawn: (1) the rate and amount of soil erosion is related not only with land use/land cover regime but also with whether there are abundant erodible sources provided for erosion. (2) During 1960 to 1978, in the beginning of land use change, naturally selective erosion was dominant. Then the percentage of surface soil erosion increased, and became dominant in the subsequent phase. Soil erosion was decreased but rocky desertification expanded in a higher rate. So it can be deduced that there was a lag between the development of rocky desertification and soil erosion;(4) The accelerated soil erosion resulted from the stir of soil during the implementation of ecological engineering was detected between 1990 to 2002, in view of which, a suggestion was put forward in this paper that ecological constructions and engineering towards water and soil maintenance should pay attention to the problem of soil erosion followed, especially should avoid the stir of soil. © 2011 Published by Elsevier Ltd.

Xin Z.,Beijing Forestry University | Yu X.,Beijing Forestry University | Lu X.X.,National University of Singapore
Earth Surface Processes and Landforms | Year: 2011

The Loess Plateau in China, an area with some of the highest sediment yield in the world, contributes predominant proportion of the sediments found in the Yellow River. We examined sediment yield and its control variables in the plateau based on a multi-year dataset from 180 gauging stations in areas varying in size from 102 to 104km2. Various morphometric, hydrologic, climatic and land cover variables were estimated in order to understand and predict the variations in sediment yield. The results show a spatial pattern of sediment yield exhibiting an obvious zonal distribution and a coupling between precipitation and vegetation cover that fits the Langbein-Schumm law. A critical threshold of precipitation and vegetation cover was observed among the relationships of sediment yield and precipitation/vegetation cover. A multiple regression equation with three control variables, i.e. vegetation cover, percentage of cultivated loess and annual runoff, explains 65% of the total variation in sediment yield. For the loess dominated basins, where the cultivated loess accounts for more than 60% of the total area, annual runoff was the dominant variable, explaining 76% of the observed variation in sediment yield. The established equation could be a valuable tool for predicting total sediment yield in the Loess Plateau. © 2010 John Wiley & Sons, Ltd.

Ao Y.,Beijing Forestry University | Ao Y.,National Energy R c nter for Non food Biomass
Genetics and Molecular Research | Year: 2016

An increasing number of microRNAs (miRNAs) are known to play crucial regulatory roles in floral organ differentiation and development. Yellow-horn (Xanthoceras sorbifolia Bunge) is an oil-rich seed shrub that has great potential for biodiesel production. To evaluate the roles of miRNAs in the regulation of flower development, we used high-throughput sequencing to characterize them from flower buds of double-flower yellow-horn mutant and wild-type plants. Approximately 33 million raw reads were obtained through Solexa sequencing of two small RNA libraries, and the conserved and novel miRNA locations were annotated. Nineteen conserved miRNAs (belonging to nine families) and eight novel miRNAs were identified from the two libraries. Twelve conserved and eight novel miRNA-star sequences were also discovered, providing additional evidence for the existence of miRNAs in this species. Thirteen miRNAs were differentially expressed between wild-type and mutant plants. Real-time reverse transcription-polymerase chain reaction analysis revealed the expression patterns of eight microRNAs, which were confirmed by sequencing. The assessed targets of these miRNAs are involved in transcriptional regulation, disease resistance, antioxidative metabolism, nucleobase regulation, and nucleic acid metabolism. This study opens up new avenues for understanding the roles of miRNAs in X. sorbifolia. © 2016 The Authors.

Liu T.,University of Hong Kong | Qi Y.,Beijing Forestry University | Cao G.,Peking University | Liu H.,Chinese University of Hong Kong
Journal of Geographical Sciences | Year: 2015

China has witnessed unprecedented urbanization over the past decades. The rapid expansion of urban population has been dominantly contributed by the floating population from rural areas, of which the spatiotemporal patterns, driving forces, and multidimensional effects are scrutinized and evaluated in this study by using the latest national censuses conducted in 2000 and 2010. Analysis based on the county-level data comes to conclusions as follows. The spatial pattern of floating population has remained stable over the first decade of the new century. The top 1% cities with the largest floating population received 45.5% of all migrants in China. As the rapid development of mega-city regions, the coastal concentration areas of floating population tended to geographically united as a whole, whereas the spatial distribution of migrants within each region varied significantly. The migrant concentration area in the Yangtze River Delta was the largest and its expansion was also the most salient. However, the floating population has growingly moved into provincial capitals and other big cities in the inland regions and its gravity center has moved northward for around 110 km during the study period. The spatial pattern of floating population has been formed jointly by the state and market forces in transitional China and the impacts of state forces have been surpassed by those of market forces in the country as a whole. The attractiveness of coastal cities and counties to the floating population comes mainly from the nonagricultural employment opportunities and public services, reflecting that long-distance and long-term migrants have moved coastward not only to gain employment but also to enjoy city life. By contrast, in the central and western regions, places with a higher economic development level and at a higher administrative level are more attractive to floating populations, demonstrating that the state remains to play an important role in allocating economic resources and promoting regional development in inland China. As the main body of new urban residents, the floating population has contributed substantially to the elevation of the urbanization levels of migrant-sending and -receiving places, by 20.0% and 49.5% respectively. Compared with extensively investigated interprovincial migrants, intra-provincial migrants have higher intention and ability to permanently live in cities and thus might become the main force of China’s urbanization in the coming decades. The internal migration has also reshaped China’s urban system in terms of its hierarchical organization and spatial structure. © 2015, Science in China Press and Springer-Verlag Berlin Heidelberg.

Wang L.,Beijing Normal University | Silvan-Cardenas J.L.,Research Center En Geografia omatica Ing Jorge mayo | Yang J.,Beijing Forestry University | Frazier A.E.,State University of New York at Buffalo
Professional Geographer | Year: 2013

Saltcedar is commonly recognized as one of the most threatening invasive species in the United States and has the potential to cause great environmental harm over the coming decade. Accurate mapping of saltcedar distribution and abundance in a timely manner plays a central role in assisting with effective control. Current studies have mostly concentrated on large-area detection with coarse-resolution remote sensing data. In this study, a comprehensive test was designed and carried out to examine the ability to integrate multitemporal and multiresolution imagery for differentiating saltcedar from other riparian vegetation types in the Rio Grande basin of Texas, including very high spatial resolution (QuickBird), hyperspectral resolution imagery (AISA), and moderate resolution satellite imagery (Landsat TM). Two types of analyses were fulfilled. First, five pixel-based classification methods were adopted for assessing the effectiveness of QuickBird and AISA for discerning saltcedar, respectively; that is, the maximum likelihood classifier (MLC), neural network classifier (NNC), support vector machine (SVM), spectral angle mapper (SAM), and maximum matching feature (MMF). Second, Landsat TM imagery was synthesized from AISA and tested for mapping the abundance of saltcedar with four linear spectral unmixing methods and three back-propagation neural network methods. Results indicate that AISA outperformed QuickBird imagery in differentiating saltcedar from other riparian vegetation species. SVM achieved the highest classification accuracy among the five classifiers. Linear spectral unmixing methods exhibited similar mapping accuracy to neural network methods in estimating the abundance of saltcedar at a spatial resolution of 30 by 30 m2 but with significantly better computing efficiency. © 2013 Copyright Taylor and Francis Group, LLC.

Huang H.,Beijing Forestry University | Qin W.,Science Systems And Applications Inc. | Liu Q.,Beijing Normal University
Remote Sensing of Environment | Year: 2013

A novel computer graphics-based radiosity model applicable to porous individual thin objects, named RAPID, is developed for fast calculation of multiple scattering and bidirectional reflectance factor (BRF) over complex, vegetated scenes. Instead of hundreds of small leaf facets, only a small number of porous thin objects are used to construct a complex tree crown or crop canopy. With gaps inside the object, it can effectively represent a group of small leaves. Each porous object has several properties, including shape, size (R), thickness (H), leaf area index (LAI), leaf angle distribution (LAD) and leaf clumping conditions (C). These properties are used to dynamically create the small leaves at run-time; hence, only view factors between porous objects (not between hundreds of small leaves) need to be calculated and stored. As a result, the model significantly reduces the huge memory requirement and long computation time of view factors for a large, realistic vegetation scene. RAPID is able to simulate arbitrary vegetation canopies in complex landscapes and to calculate BRF within a few minutes, which makes its application possible on different satellite pixel levels. This innovative technique is evaluated by comparing with directional reflectances from other models as well as field measurements. © 2013 Elsevier Inc.

Jiang X.,Northwest University, China | Janz D.,Beijing Forestry University | Polle A.,University of Gottingen
Plant Physiology | Year: 2013

Bark tissue of Populus × canescens can hyperaccumulate cadmium, but microstructural, transcriptomic, and physiological response mechanisms are poorly understood. Histochemical assays, transmission electron microscopic observations, energydispersive x-ray microanalysis, and transcriptomic and physiological analyses have been performed to enhance our understanding of cadmium accumulation and detoxification in P. × canescens. Cadmium was allocated to the phloem of the bark, and subcellular cadmium compartmentalization occurred mainly in vacuoles of phloem cells. Transcripts involved in microstructural alteration, changes in nutrition and primary metabolism, and stimulation of stress responses showed significantly differential expression in the bark of P. × canescens exposed to cadmium. About 48% of the differentially regulated transcripts formed a coregulation network in which 43 hub genes played a central role both in cross talk among distinct biological processes and in coordinating the transcriptomic regulation in the bark of P. × canescens in response to cadmium. The cadmium transcriptome in the bark of P. × canescens was mirrored by physiological readouts. Cadmium accumulation led to decreased total nitrogen, phosphorus, and calcium and increased sulfur in the bark. Cadmium inhibited photosynthesis, resulting in decreased carbohydrate levels. Cadmium induced oxidative stress and antioxidants, including free proline, soluble phenolics, ascorbate, and thiol compounds. These results suggest that orchestrated microstructural, transcriptomic, and physiological regulation may sustain cadmium hyperaccumulation in P. × canescens bark and provide new insights into engineering woody plants for phytoremediation. © 2013 American Society of Plant Biologists. All Rights Reserved.

Qiu Z.,Beijing Forestry University | Qiu Z.,Henan Normal University | Qiu Z.,CAS Institute of Botany | Wan L.,CAS Institute of Botany | And 6 more authors.
New Phytologist | Year: 2013

Chinese fir (Cunninghamia lanceolata), a commercially important tree for the timber and pulp industry, is widely distributed in southern China and northern Vietnam, but its large and complex genome has hindered the development of genomic resources. Few efforts have focused on analysis of the modulation of transcriptional networks in vascular cambium during the transition from active growth to dormancy in conifers. Here, we used Illumina sequencing to analyze the global transcriptome alterations at the different stages of vascular cambium development in Chinese fir. By analyzing dynamic changes in the transcriptome of vascular cambium based on our RNA sequencing (RNA-Seq) data at the dormant, reactivating and active stages, many potentially interesting genes were identified that encoded putative regulators of cambial activity, cell division, cell expansion and cell wall biosynthesis and modification. In particular, the genes involved in transcriptional regulation and hormone signaling were highlighted to reveal their biological importance in the cambium development and wood formation. Our results reveal the dynamics of transcriptional networks and identify potential key components in the regulation of vascular cambium development in Chinese fir, which will contribute to the in-depth study of cambial differentiation and wood-forming candidate genes in conifers. © 2013 New Phytologist Trust.

Liu Z.,Harvard University | Liu Z.,CAS Shenyang Institute of Applied Ecology | Liu Z.,California Institute of Technology | Guan D.,Tsinghua University | And 29 more authors.
Nature | Year: 2015

Nearly three-quarters of the growth in global carbon emissions from the burning of fossil fuels and cement production between 2010 and 2012 occurred in China. Yet estimates of Chinese emissions remain subject to large uncertainty; inventories of China's total fossil fuel carbon emissions in 2008 differ by 0.3 gigatonnes of carbon, or 15 per cent. The primary sources of this uncertainty are conflicting estimates of energy consumption and emission factors, the latter being uncertain because of very few actual measurements representative of the mix of Chinese fuels. Here we re-evaluate China's carbon emissions using updated and harmonized energy consumption and clinker production data and two new and comprehensive sets of measured emission factors for Chinese coal. We find that total energy consumption in China was 10 per cent higher in 2000-2012 than the value reported by China's national statistics, that emission factors for Chinese coal are on average 40 per cent lower than the default values recommended by the Intergovernmental Panel on Climate Change, and that emissions from China's cement production are 45 per cent less than recent estimates. Altogether, our revised estimate of China's CO2 emissions from fossil fuel combustion and cement production is 2.49 gigatonnes of carbon (2 standard deviations = ±7.3 per cent) in 2013, which is 14 per cent lower than the emissions reported by other prominent inventories. Over the full period 2000 to 2013, our revised estimates are 2.9 gigatonnes of carbon less than previous estimates of China's cumulative carbon emissions. Our findings suggest that overestimation of China's emissions in 2000-2013 may be larger than China's estimated total forest sink in 1990-2007 (2.66 gigatonnes of carbon) or China's land carbon sink in 2000-2009 (2.6 gigatonnes of carbon). © 2015 Macmillan Publishers Limited. All rights reserved.

Wang H.,Beijing Forestry University | Bian Z.,Beijing Normal University | Lu G.,Beijing Forestry University | Pang L.,Beijing Forestry University | And 2 more authors.
Applied Catalysis B: Environmental | Year: 2012

Multifunctional gas-diffusion electrode with electrochemical reduction and oxidation properties was achieved based on the palladium-modified activated carbon (Pd/C). Pd/C catalysts were prepared using the formaldehyde reduction from nitric acid treated activated carbon and fully characterized by Boehm titration method, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and cyclic voltammetry (CV) techniques. The electrochemical degradation of three typical chlorinated phenols (4-chlorophenol, 2,4-dichlorophenol and pentachlorophenol) was investigated in a diaphragm electrolysis system with the Pd/C gas-diffusion electrode as a cathode, feeding firstly with hydrogen gas and then with air. The electrolysis system with 15% mass fraction nitric acid pretreated activated carbon showed better electrocatalytic activity compared to those from other mass fractions nitric acid, due to the active organic function groups increased on the surface of the activated carbon. When the ratio of Pd/C was low, Pd particles with an average size of 3.5nm were highly dispersed in the activated carbon with an amorphous structure. The Pd/C gas-diffusion cathode cannot only reductively dechlorinate chlorinated phenols by feeding hydrogen gas, but also accelerate the two-electron reduction of O 2 to H 2O 2 by feeding air. Therefore, the removal efficiency of chlorinated phenols reached almost 100%, conforming to the sequence of 4-chlorophenol, 2,4-dichlorophenol and pentachlorophenol. The dechlorination of three chlorinated phenols exceeded 80% after 100min. For H 2O 2 and HO existed in the catholyte, the mineralization of organic pollutants in the cathodic compartment was better than that in the anodic compartment. Finally, chlorinated organic pollutants were efficiently degraded by the combined processes of reduction and oxidation in the present system. © 2012 Elsevier B.V.

Lv Z.,Beijing Forestry University | Zhang B.,Beijing Forestry University
BioResources | Year: 2012

This paper provides an applicable approach to identifying flavonoid compounds from bamboo leaves extracts, based on the use of the powerful Liquid Chromatography Electrospray Ionization source in combination with hybrid Ion Trap and high-resolution Time-of-flight Mass Spectrometry (LC-(ESI)-IT-TOF/MS). The strategy involves four procedural steps including searching flavonoid components based on an ultraviolet spectrum scan, getting the accurate mass of flavonoid components parent ion, retrieving the corresponding formula by software, and speculating as to the chemical structure according to mass spectrum decomposition rules. The presently developed methodology has been well proven to be useful and valuable by successful application to the identification of flavonoid components from Dendrocalamopsis oldham leaves. All of the 13 flavonoid components detected have been successfully identified by this approach, except that it failed to confirm 3 flavonoid component chemical structures. The calibration curves of two flavonoid components (orientin and vitexin) that had been identified in bamboo leaves showed a good linear fit (R2=0.9998) in the concentration range of 6.25 to 200 mg/L. The limits of detection (LOD) were less 0.02 mg/L (S/N=3), and the estimated limits of quantification (LOQ) were less 0.06 mg/L (S/N=10). Intra- and inter-day relative standard deviations were less than 1.04 and 1.82%, respectively.

Pang L.,Beijing Forestry University | Wang H.,Beijing Forestry University | Bian Z.Y.,Beijing Normal University
Water Science and Technology | Year: 2013

Electrochemical oxidation of methyl orange wastewater was studied using Ti/IrO2/RuO2 anode and a self-made Pd/C O2-fed cathode in the divided cell with a terylene diaphragm. The result indicated that the appropriate rate of feeding air improved the methyl orange removal efficiency. The discoloration efficiency of methyl orange in the divided cell increased with increasing current density. The initial pH value had some effect on the discoloration of methyl orange, which became not obvious when the pH ranged from 2 to 10. However, the average removal efficiency of methyl orange wastewater in terms of total organic carbon (TOC) can reach 89.3%. The methyl orange structure had changed in the electrolytic process, and the characteristic absorption peak of methyl orange was about 470 nm. With the extension of electrolysis time, the concentration of methyl orange gradually reduced; wastewater discoloration rate increased gradually. The degradation of methyl orange was assumed to be cooperative oxidation by direct or indirect electrochemical oxidation at the anode and H2O2, ·OH, O2 · produced by oxygen reduction at the cathode in the divided cell. Therefore, the cooperative electrochemical oxidation of methyl orange wastewater in the anodic-cathodic compartment had better degradation effects. © IWA Publishing 2013.

Ran L.,National University of Singapore | Lu X.X.,National University of Singapore | Lu X.X.,Inner Mongolia University | Xin Z.,Beijing Forestry University
Biogeosciences | Year: 2014

Soil erosion and terrestrial deposition of soil organic carbon (SOC) can potentially play a significant role in global carbon cycling. Assessing the redistribution of SOC during erosion and subsequent transport and burial is of critical importance. Using hydrological records of soil erosion and sediment load, and compiled organic carbon (OC) data, estimates of the eroded soils and OC induced by water in the Yellow River basin during the period 1950-2010 were assembled. The Yellow River basin has experienced intense soil erosion due to combined impact of natural process and human activity. Over the period, 134.2 ± 24.7 Gt of soils and 1.07 ± 0.15 Gt of OC have been eroded from hillslopes based on a soil erosion rate of 1.7-2.5 Gt yr-1. Approximately 63% of the eroded soils were deposited in the river system, while only 37% were discharged into the ocean. For the OC budget, approximately 0.53 ± 0.21 Gt (49.5%) was buried in the river system, 0.25 ± 0.14 Gt (23.5%) was delivered into the ocean, and the remaining 0.289 ± 0.294 Gt (27%) was decomposed during the erosion and transport processes. This validates the commonly held assumption that 20-40% of the eroded OC would be oxidized after erosion. Erosion-induced OC redistribution on the landscape likely represented a carbon source, although a large proportion of OC was buried. In addition, about half of the terrestrially redeposited OC (49.4%) was buried behind dams, revealing the importance of dam trapping in sequestering the eroded OC. Although several uncertainties need to be better constrained, the obtained budgetary results provide a means of assessing the redistribution of the eroded OC within the Yellow River basin. Human activities have significantly altered its redistribution pattern over the past decades. © Author(s) 2014.

Li L.,National Flower Engineering Research Center | Cheng F.-Y.,Beijing Forestry University | Zhang Q.-X.,National Flower Engineering Research Center
American Journal of Botany | Year: 2011

Premise of the study: Microsatellite (simple sequence repeat, SSR) primers were developed for the Chinese peony, P. lactiflora, to investigate the diversity within Chinese peony germplasm resources. Methods and Results: Using an SSR-enriched genomic library, a set of 10 unique polymorphic genomic SSRs was developed and characterized. The primers amplified 61 alleles in all 10 loci, including di-, tri-, and tetranucleotide repeats. The primers were also effective for P. veitchii and P. obovata. Conclusions: The new primers will be useful for genetic research of the Chinese peony and extend the repertoire of SSR markers available to study the herbaceous taxa in Paeonia. © 2011 Botanical Society of America.

Huang X.,Chinese Academy of Forestry | Liu S.,Chinese Academy of Forestry | Wang H.,Chinese Academy of Forestry | Hu Z.,Sichuan Agricultural University | And 2 more authors.
Soil Biology and Biochemistry | Year: 2014

In this study we examined the effects of mixing N-fixing species with Eucalyptus on microbial biomass carbon (MBC) and phospholipid fatty acid (PLFA) composition using a comparative experiment of an 8-year-old pure E ucalyptus urophylla plantation (PP) and an 8-year-old mixed E.urophylla and Acacia mangium plantation (MP) in Guangxi Zhuang Autonomous Region, southern China. Additionally, a trench control experiment was conducted to distinguish the effects of roots on MBC and community structure. The results showed that the number and abundance of PLFAs and MBC were higher in MP than that in PP. The soil TOC, NH4-N, NO3-N, TN and litterfall mass were significantly higher in surface soil (0-10cm) in MP; whereas the C/N ratios of soil and litterfall were significantly lower by 37.6% and 78.5%, respectively, in MP than in PP. MBC at the surface soil (0-10cm) was significantly higher by 9.0% in MP than in PP. Principal Component Analysis (PCA) indicated that soil microbial community structure differed between the two plantations, and between the trenched and untrenched plots. Redundancy analysis (RDA) also revealed that C/N ratios of soil and litterfall, TOC, NH4-N, litterfall mass and NO3-N were key factors affecting the soil microbial community regardless of plantation types.Our study suggests that mixing N-fixing species into E.urophylla plantations can enhance soil C sequestration by increasing TOC and MBC, as well as through increased soil microbial community diversity and abundance. Findings from this study could assist sustainable management of Eucalyptus plantations for biomass carbon production, soil C sequestration and retention. © 2014.

Bian Z.-Y.,Beijing Normal University | Zhu Y.-Q.,Beijing Forestry University | Zhang J.-X.,Beijing Normal University | Ding A.-Z.,Beijing Normal University | Wang H.,Beijing Forestry University
Chemosphere | Year: 2014

An efficient method for the degradation of ibuprofen as an aqueous contaminant was developed under visible-light irradiation with as-prepared bismuth vanadate (BiVO4) catalysts. The metal-loaded catalysts Cu-BiVO4 and Ag-BiVO4 were synthesized using a hydrothermal process and then a wet-impregnation method. All of the materials were fully characterized by X-ray diffraction, scanning electron microscopy, UV-vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy and BET surface area. The results indicated that all of the prepared samples had monoclinic scheelite structures. In the metal-loaded catalysts, silver existed as a mixture of Ag and Ag2O on the surface of the catalysts. However, copper existed as Cu2O and CuO. Additionally, the band gap values of BiVO4, Ag-BiVO4, and Cu-BiVO4 were 2.38, 2.31, and 2.30eV, respectively. Compared to the BiVO4 catalyst, the metal-loaded BiVO4 catalysts showed superior photocatalytic properties for the degradation of ibuprofen. © 2014 Elsevier Ltd.

Ma J.-X.,Beijing Normal University | Ma J.-X.,Beijing Engineering Research Center for Hybrid Wheat | Li Y.-N.,Beijing Forestry University | Vogl C.,University of Veterinary Medicine Vienna | And 2 more authors.
BMC Evolutionary Biology | Year: 2010

Background. In the flowering plants, many polyploid species complexes display evolutionary radiation. This could be facilitated by gene flow between otherwise separate evolutionary lineages in contact zones. Achillea collina is a widespread tetraploid species within the Achillea millefolium polyploid complex (Asteraceae-Anthemideae). It is morphologically intermediate between the relic diploids, A. setacea-2x in xeric and A. asplenifolia-2x in humid habitats, and often grows in close contact with either of them. By analyzing DNA sequences of two single-copy nuclear genes and the genomic AFLP data, we assess the allopolyploid origin of A. collina-4x from ancestors corresponding to A. setacea-2x and A. asplenifolia-2x, and the ongoing backcross introgression between these diploid progenitor and tetraploid progeny lineages. Results. In both the ncpGS and the PgiC gene tree, haplotype sequences of the diploid A. setacea-2x and A. asplenifolia-2x group into two clades corresponding to the two species, though lineage sorting seems incomplete for the PgiC gene. In contrast, A. collina-4x and its suspected backcross plants show homeologous gene copies: sequences from the same tetraploid individual plant are placed in both diploid clades. Semi-congruent splits of an AFLP Neighbor Net link not only A. collina-4x to both diploid species, but some 4x individuals in a polymorphic population with mixed ploidy levels to A. setacea-2x on one hand and to A. collina-4x on the other, indicating allopolyploid speciation as well as hybridization across ploidal levels. Conclusions. The findings of this study clearly demonstrate the hybrid origin of Achillea collina-4x, the ongoing backcrossing between the diploid progenitor and their tetraploid progeny lineages. Such repeated hybridizations are likely the cause of the great genetic and phenotypic variation and ecological differentiation of the polyploid taxa in Achillea millefolium agg. © 2010 Ma et al; licensee BioMed Central Ltd.

Agency: European Commission | Branch: FP7 | Program: CSA-CA | Phase: KBBE-2008-1-2-07 | Award Amount: 1.17M | Year: 2009

The project first assesses the state of the art of SRF as a biofuel source in CDM and JI countries (wp1) focuses on CDM countries (wp2) and links the project to current European and non-European R&D-activities in the area (wp3). Main outputs: 1) SRF guidelines and standards for land use management (wp4) for farmers and European JI/CDM project developers as well as stakeholders from the energy and biomass sector (electric utilities, pulp & paper, fibreboard etc.) 2) a SRF R&D agenda (wp5) for researchers and industry (boiler, oven, chipper, press producers etc.)

Gong C.,Beijing Forestry University | Xu C.,North China University of Water Conservancy and Electric Power | Chen L.,CAS Institute of Soil and Water Conservation | Cao S.,Beijing Forestry University
Forest Policy and Economics | Year: 2012

Compensation payment schemes play an important role in conservation efforts around the world, particularly for implementing agri-environmental policy. Unfortunately, huge investments such as those conducted in China under the Grain for Green Program (GGP) and elsewhere around the world have historically provided few long-term benefits. To design a cost-effective compensation policy for ecological restoration, the approach must integrate economic and ecological components. Here, we describe such a policy model ("Buying Green Cover") and compare it with an existing approach, the GGP, using data from China's Northern Shaanxi Province. The modified compensation program pays farmers to build terraced farmland or perform other "green" activities that will also sustain their livelihoods once the program ends. The resulting program costs 30% less than the GGP, and will take only 3 to 7. years to achieve the GGP's 16-year goal of converting sloping farmland into forests and grassland. In contrast with the failures of the GGP and related programs, the new approach improves the management and restoration of rapidly degrading landscapes and should be applicable both in China and around the world. © 2011 Elsevier B.V.

Zha T.,Beijing Forestry University | Barr A.G.,Environment Canada | van der Kamp G.,Environment Canada | Black T.A.,University of British Columbia | And 2 more authors.
Agricultural and Forest Meteorology | Year: 2010

Climate models predict rising temperatures and more frequent and prolonged droughts, particularly in the northern hemisphere and in the Canadian Prairies. However, few studies have examined the interannual variation in evapotranspiration (E) of northern terrestrial ecosystems in relation to drought. This study analyses multi-year (1998-2006), eddy-covariance measurements to quantify the seasonal and interannual variability in E from grassland and mature aspen, black spruce, and jack pine forest ecosystems in the dry interior plains of western Canada. It also investigates the response of E to the historic 2001-2003 drought in this region. Leaf area index (LAI) was a primary factor controlling the difference in E among different ecosystems in the same ecozone. Annual E was higher and more variable for the aspen forest (405 ± 84 mm, mean ± s.d.) and grassland (395 ± 90 mm) than the black spruce (374 ± 34 mm) and jack pine (300 ± 20 mm) forests. Interannual variation of E was controlled by early spring soil temperature at all four sites, with warm springs enhancing annual E. Only the aspen forest and grassland showed a significant suppression of E by summer drought, related to reduced surface conductance at the aspen site, and to reduced surface conductance and early leaf senescence at the grassland. We conclude that the potential for drought impacts on annual E of northern ecosystems is greatest for grasslands, moderate for deciduous broadleaf aspen forests, and smallest for coniferous black spruce and jack pine forests. The forests of the Boreal Plains, adjacent to the prairie region, may ameliorate the onset of drought through the recycling of moisture to the atmosphere, whereas the prairie grasslands have only limited capacity to counteract drought through moisture recycling. © 2010.

Yuan J.-H.,Chinese Academy of Sciences | Yuan J.-H.,Beijing Forestry University | Cornille A.,University Paris - Sud | Cornille A.,French National Center for Scientific Research | And 6 more authors.
Molecular Ecology | Year: 2014

An understanding of plant domestication history provides insights into general mechanisms of plant adaptation and diversification and can guide breeding programmes that aim to improve cultivated species. Cultivated tree peonies (genus Paeonia L.) are among the most popular ornamental plants in the world; yet, the history of their domestication is still unresolved. Here, we explored whether the domestication in China of historically cultivated peonies, that is, the common and flare cultivated tree peonies, was a single event or whether independent domestications occurred. We used 14 nuclear microsatellite markers and a comprehensive set of 553 tree peonies collected across China, including common tree peonies, flare tree peonies and the wild species or subspecies that are potential contributors to the cultivated tree peonies, that is, Paeonia rockii ssp. rockii, P. rockii ssp. atava, P. jishanensis and P. decomposita. Assignment methods, a principal component analysis and approximate Bayesian computations provided clear evidence for independent domestications of these common tree and flare tree peonies from two distinct and allopatric wild species, P. jishanensis and P. rockii ssp. atava, respectively. This study provides the first example of independent domestications of cultivated trees from distinct species and locations. This work also yields crucial insight into the history of domestication of one of the most popular woody ornamental plants. The cultivated peonies represent an interesting case of parallel and convergent evolution. The information obtained in this study will be valuable both for improving current tree peony breeding strategies and for understanding the mechanisms of domestication, diversification and adaptation in plants. © 2013 John Wiley & Sons Ltd.

Wang P.,Beijing Forestry University | Lei J.-P.,Chinese Academy of Forestry | Li M.-H.,Swiss Federal Institute of forest | Yu F.-H.,Beijing Forestry University
PLoS ONE | Year: 2012

Spatial heterogeneity in light supply is common in nature. Many studies have examined the effects of heterogeneous light supply on growth, morphology, physiology and biomass allocation of clonal plants, but few have tested those effects on intraspecific competition. In a greenhouse experiment, we grew one (no competition) or nine ramets (with intraspecific competition) of a stoloniferous clonal plant, Duchesnea indica, in three homogeneous light conditions (high, medium and low light intensity) and two heterogeneous ones differing in patch size (large and small patch treatments). The total light in the two heterogeneous treatments was the same as that in the homogeneous medium light treatment. Both decreasing light intensity and intraspecific competition significantly decreased the growth (biomass, number of ramets and total stolon length) of D. indica. As compared with the homogeneous medium light treatment, the large patch treatment significantly increased the growth of D. indica without intraspecific competition. However, the growth of D. indica with competition did not differ among the homogeneous medium light, the large and the small patch treatments. Consequently, light heterogeneity significantly increased intraspecific competition intensity, as measured by the decreased log response ratio. These results suggest that spatial heterogeneity in light supply can alter intraspecific interactions of clonal plants. © 2012 Wang et al.

Gao Y.,Beijing Forestry University | Wang Q.,Beijing Forestry University | Wang J.,Beijing Forestry University | Huang L.,Beijing Forestry University | And 5 more authors.
ACS Applied Materials and Interfaces | Year: 2014

High-density polyethylene (HDPE) polymer nanocomposites containing Zn 2Al-X (X= CO3 2-, NO3 -, Cl-, SO4 2-) layered double hydroxide (LDH) nanoparticles with different loadings from 10 to 40 wt % were synthesized using a modified solvent mixing method. Synthesized LDH nanofillers and the corresponding nanocomposites were carefully characterized using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, etc. The thermal stability and flame retardancy behavior were investigated using a thermo gravimetric analyzer and microscale combustion calorimeter. Comparing to neat HDPE, the thermal stability of nanocomposites was significantly enhanced. With the addition of 15 wt % Zn2Al-Cl LDH, the 50% weight loss temperature was increased by 67 °C. After adding LDHs, the flame retardant performance was significantly improved as well. With 40 wt % of LDH loading, the peak heat release rate was reduced by 24%, 41%, 48%, and 54% for HDPE/Zn2Al-Cl, HDPE/Zn2Al-CO3, HDPE/Zn2Al-NO3, and HDPE/Zn2Al-SO4, respectively. We also noticed that different interlayer anions could result in different rheological properties and the influence on storage and loss moduli follows the order of SO4 2- > NO3 - > CO3 2- > Cl-. Another important finding of this work is that the influence of anions on flame retardancy follows the exact same order on rheological properties. © 2014 American Chemical Society.

Wu C.,Beijing Forestry University | Zhang G.,Renmin University of China | Zhang P.,Beijing Forestry University | Chang C.-C.,District of Columbia Water and Sewer Authority | Chang C.-C.,University of Maryland Baltimore County
Chemical Engineering Journal | Year: 2014

Sludge disintegration destroys the sludge floc structure and releases the extracellular polymeric substances (EPS) and cell contents into the liquid phase, to enhance the sludge anaerobic digestion. Potential benefits of potassium permanganate (KMnO4) disintegrating excess sludge were investigated in this paper. Sludge disintegration feasibility was analyzed with soluble chemical oxygen demand (SCOD) increase in supernatant. Sludge disintegration mechanisms were explored with analyzing the change of particle size, EPS, oxidation reduction potential (ORP) and Mn state. Sludge disintegration process was optimized through analyzing disintegration degree (DDCOD). Results showed that KMnO4 effectively disintegrated the excess sludge with a SCOD increase of 3473% and more than 97% of Mn transferred into the solid phase. A slow decrease in particle size was observed. EPS was efficiently released into supernatant, and supernatant proteins and polysaccharides increased by 490% and 141%, respectively. Loosely bound EPS increased by 498%, which was much higher than slime EPS and tightly bound EPS. The main mechanism of sludge disintegration was KMnO4 oxidation. After sludge oxidation, KMnO4 mainly transferred to the sludge solids with the states of MnO2 and Mn3O4, and a state of KxMnO4 also existed in the solids. Optimization experiments showed that suitable reaction time was 30min, and KMnO4/sludge solid mass ratio was the most important factor and its optimal value was 0.1 with a stable DDCOD of about 34%. © 2013 Elsevier B.V.

Li F.,Beijing Forestry University | Yin Y.,East China Institute of Technology
Information Sciences | Year: 2012

In this paper, we consider a semigroup as a universal set and investigate the properties of v-lower and T-upper fuzzy rough approximation operators. A new fuzzy algebraic structure, called a TL-fuzzy rough semigroup, is introduced and some related properties are studied. Finally, the homomorphism properties of -lower and T-upper fuzzy rough approximation operators are investigated. © 2012 Elsevier Inc. All rights reserved.

Li Q.,Beijing Forestry University | Li Q.,North China University of Water Conservancy and Electric Power | Yu X.,Beijing Forestry University | Xin Z.,Beijing Forestry University | Sun Y.,North China University of Water Conservancy and Electric Power
Journal of Hydrologic Engineering | Year: 2013

The hydrological cycle in a catchment is sensitive to climate and land-use changes. The authors conducted a case study to validate the performance of the soil and water assessment tool (SWAT) and its applicability as a simulator of runoff and sediment transport processes at the mesoscale scale in arid and semiarid areas. SWAT is used to simulate runoff and sediment changes caused by human activities in a typical watershed, the Jihe Watershed (1;019 km2), in the Loess Plateau of northwestern China. A marked increase in temperature was observed over the analysis period. The investigation was conducted using 47 years of historical rainfall/runoff data and sedimentary records from 1962-2008. The data from 1962-1981 was used for calibration and that from 1982-2008 for validation. The results showed that the Nash-Sutcliffe model efficiency coefficient was approximately 0.7, the relative error was less than 15%, and the coefficient of determination was greater than 0.7, both for annual flow and sediment yield in the calibration period. These findings indicate that the SWAT model was able to simulate runoff and sediment yield satisfactorily; however, it exhibited better performance for the calibration period than for the validation period. Similarly, simulations of monthly flow and sediment were better for the calibration period. The simulated and observed values agree well with trend changes. Uncertainty analysis indicates that digital elevation model resolutions and watershed subdivisions imposed little influence on annual flow, but notable effects were observed with respect to annual sediment yield. © 2013 American Society of Civil Engineers.

Fan J.,Beijing Forestry University | Johnson M.H.,University of Illinois at Urbana - Champaign | Lila M.A.,North Carolina State University | Yousef G.,North Carolina State University | De Mejia E.G.,University of Illinois at Urbana - Champaign
Evidence-based Complementary and Alternative Medicine | Year: 2013

Beneficial health effects of fruits and vegetables in the diet have been attributed to their high flavonoid content. Dipeptidyl peptidase IV (DPP-IV) is a serine aminopeptidase that is a novel target for type 2 diabetes therapy due to its incretin hormone regulatory effects. In this study, well-characterized anthocyanins (ANC) isolated from berry wine blends and twenty-seven other phenolic compounds commonly present in citrus, berry, grape, and soybean, were individually investigated for their inhibitory effects on DPP-IV by using a luminescence assay and computational modeling. ANC from blueberry-blackberry wine blends strongly inhibited DPP-IV activity (IC50, 0.07 ± 0.02 to >300 M). Of the twenty-seven phenolics tested, the most potent DPP-IV inhibitors were resveratrol (IC50, 0.6 ± 0.4 nM), luteolin (0.12 ± 0.01 M), apigenin (0.14 ± 0.02 M), and flavone (0.17 ± 0.01 M), with IC50 values lower than diprotin A (4.21 ± 2.01 M), a reference standard inhibitory compound. Analyses of computational modeling showed that resveratrol and flavone were competitive inhibitors which could dock directly into all three active sites of DPP-IV, while luteolin and apigenin docked in a noncompetitive manner. Hydrogen bonding was the main binding mode of all tested phenolic compounds with DPP-IV. These results indicate that flavonoids, particularly luteolin, apigenin, and flavone, and the stilbenoid resveratrol can act as naturally occurring DPP-IV inhibitors. © 2013 Junfeng Fan et al.

Jian H.-L.,Beijing Forestry University | Jian H.-L.,Anhui Agricultural University | Lin X.-J.,Beijing Forestry University | Zhang W.-A.,Beijing Forestry University | And 3 more authors.
Food Hydrocolloids | Year: 2014

Three galactomannans of guar gum (GG), locust bean gum (LBG) and fenugreek gum (FG) were fractionally precipitated from pure solutions by the addition of either ethanol or isopropanol. The galactomannan precipitates were formed when the bulk solutions containing >18.6% (v/v) ethanol or 13.5% (v/v) isopropanol. The galactomannan recovery of GG, LBG and FG in 33.3% ethanol solvent was 93.1, 86.1 and 94.5%, respectively, while that in 28.8% isopropanol solvent was 94.1, 92.5 and 97.7%, respectively. To achieve the same precipitation efficiency, the usage amount of isopropanol was much lower than that of ethanol, owing to the low dielectric constant for isopropanol (20 vs. 25). It was demonstrated that the precipitation behavior of galactomannans in polar organic solvents was dependent on the molecular structure, such as molecular weight and galactose substitution. © 2014 Elsevier Ltd.

Cao Y.,CAS Shenyang Institute of Applied Ecology | Cao Y.,University of Chinese Academy of Sciences | Wu S.-H.,CSIC - National Museum of Natural Sciences | Wu S.-H.,National Taichung University of Education | And 2 more authors.
Fungal Diversity | Year: 2012

Lingzhi is a mushroom that has been renowned in China for more than 2,000 years because of its claimed medicinal properties plus its symbolic fortune. Lingzhi has high economic value mostly as a dietary supplement in the modern market especially in East Asia, and its medicinal functions have become a hot study topic. For over a century, the highly prized medicinal fungus, known as Lingzhi in East Asia, has been assigned to Ganoderma lucidum, a species originally described from Europe. Molecular studies in recent years have revealed that the commercially cultivated 'G. lucidum' (Lingzhi) in East Asia is a different species from the true G. lucidum. The present study aims to clarify the species identity of Lingzhi based on morphological studies and analysis of rDNA nuc-ITS sequences, and additional gene fragments of mt-SSU, RPB1, RPB2, and TEF1-α of Lingzhi were provided. All Ganoderma species that mostly resemble Lingzhi in phylogeny and /or morphology were included for analysis. We propose a new species G. lingzhi for Lingzhi, which has an East Asia distribution. The most striking characteristics which differentiate G. lingzhi from G. lucidum are the presence of melanoid bands in the context, a yellow pore surface and thick dissepiments (80-120 μm) at maturity. G. curtisii is most closely related to G. lingzhi in phylogeny and is from North America. Ganoderma flexipes, G. multipileum, G. sichuanense, G. tropicum and 'G. tsugae', are also closely related with G. lingzhi and are reported from China. These species are compared and discussed. 'Ganoderma tsuage' reported from China is determined as conspecific with G. lucidum, hence the distribution of G. lucidum extends from Europe to northeastern China. © 2012 Mushroom Research Foundation.

Yang J.,Tsinghua University | Yang J.,Beijing Forestry University | Dai G.,Beijing Forestry University | Ma L.,Beijing Forestry University | And 3 more authors.
Renewable and Sustainable Energy Reviews | Year: 2013

Forest-based bioenergy is gaining global popularity due to its multiple benefits and increased global energy needs. In this study, the current status of forest-based bioenergy in China was reviewed and the opportunities and challenges were analyzed. The latest national development plan for forest-based bioenergy was also discussed. It can be concluded from the study that forest-based bioenergy is still in the beginning stage in China but will grow rapidly in the next decade due to abundant resources and strong government support. However, there are major constraints that need to be addressed including unstable feedstock supply, low market interest and investments, inadequate R&D, and competition from other forest products. The national development plan sets up a mid-term goal for developing forest-based bioenergy but more supporting policies are required to guarantee its successful implementation. © 2012 Elsevier Ltd. All rights reserved.

Xing Z.-P.,Heilongjiang University | Sun D.-Z.,Heilongjiang University | Yu X.-J.,Heilongjiang University | Zou J.-L.,Heilongjiang University | Zhou W.,Beijing Forestry University
Environmental Progress and Sustainable Energy | Year: 2014

A continuously operated laboratory scale anaerobic and aerobic moving bed biofilm reactors (MBBRs) combined with O3/H2O2 process was experimented for antibiotic fermentation-based pharmaceutical wastewater. The experimental results indicated that 26.6% of chemical oxygen demand (COD) was removed, and 931.75 mg/L of volatile fatty acids (VFAs) was produced under the optimum conditions of the anaerobic MBBR at an influent pH of 6.5, hydraulic retention time (HRT) of 12 hr and organic loading rate (OLR) of 13 kg COD/(m3·d) for the hydrolysis/acidification process. In addition, 91.0% of COD was removed at 1.5 m3/h of aeration rate with the aerobic MBBR. The shape of bacteria inside the bio-carriers was characterized by a scanning electron microscope. The anaerobic MBBR bacteria were observed as long bacilli, and the aerobic MBBR bacteria were observed as mainly cocci and short bacilli. Finally, the residual non-biodegraded pollutants were mineralized by O3/H2O2 oxidation with 0.5 of H2O2/O3 molar ratio and 15 min of reaction time. The total removal efficiencies of COD and color reached 99.2 and 98.7%, respectively. Thus, this method might offer an effective way to treat wastewater from the pharmaceutical industry. © 2013 American Institute of Chemical Engineers.

Wang B.,Umeå University | Mao J.-F.,Beijing Forestry University | Zhao W.,CAS Institute of Botany | Wang X.-R.,Umeå University
PLoS ONE | Year: 2013

Southwest China is a biodiversity hotspot characterized by complex topography, heterogeneous regional climates and rich flora. The processes and driving factors underlying this hotspot remain to be explicitly tested across taxa to gain a general understanding of the evolution of biodiversity and speciation in the region. In this study, we examined the role played by historically neutral processes, geography and environment in producing the current genetic diversity of the subtropical pine Pinus yunnanensis. We used genetic and ecological methods to investigate the patterns of genetic differentiation and ecological niche divergence across the distribution range of this species. We found both continuous genetic differentiation over the majority of its range, and discrete isolated local clusters. The discrete differentiation between two genetic groups in the west and east peripheries is consistent with niche divergence and geographical isolation of these groups. In the central area of the species' range, population structure was shaped mainly by neutral processes and geography rather than by ecological selection. These results show that geographical and environmental factors together created stronger and more discrete genetic differentiation than isolation by distance alone, and illustrate the importance of ecological factors in forming or maintaining genetic divergence across a complex landscape. Our findings differ from other phylogenetic studies that identified the historical drainage system in the region as the primary factor shaping population structure, and highlight the heterogeneous contributions that geography and environment have made to genetic diversity among taxa in southwest China. © 2013 Wang et al.

Li S.-M.,Beijing Forestry University | Jia N.,Beijing Forestry University | Ma M.-G.,Beijing Forestry University | Zhang Z.,China Agricultural University | And 3 more authors.
Carbohydrate Polymers | Year: 2011

A facile microwave-assisted method was developed to fabricate cellulose-silver nanocomposites by reducing silver nitrate in ethylene glycol (EG). EG acts as a solvent, a reducing reagent, and a microwave absorber in the whole system, thus no additional reductant is needed. The influences of the heating time and heating temperature on the products were investigated. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscope (SEM). The thermal stability of cellulose-silver nanocomposites in nitrogen and air was studied using thermogravimetric analysis (TG) and differential scanning calorimetric analysis (DSC). Also, the cellulose-silver nanocomposites possess a high antimicrobial activity against the model microbes Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). It is expected that the cellulose-silver nanocomposites are a promising material for the application in the biomedical field. © 2011 Elsevier Ltd All rights reserved.

Cornelissen J.H.C.,VU University Amsterdam | Song Y.-B.,Hangzhou Normal University | Song Y.-B.,CAS Institute of Botany | Yu F.-H.,Beijing Forestry University | And 2 more authors.
Annals of Botany | Year: 2014

Background Clonal plants spread laterally by spacers between their ramets (shoot-root units); these spacers can transport and store resources. While much is known about how clonality promotes plant fitness, we know little about how different clonal plants influence ecosystem functions related to carbon, nutrient and water cycling. Approach The response-effect trait framework is used to formulate hypotheses about the impact of clonality on ecosystems. Central to this framework is the degree of correspondence between interspecific variation in clonal 'response traits' that promote plant fitness and interspecific variation in 'effect traits', which define a plant's potential effect on ecosystem functions. The main example presented to illustrate this concept concerns clonal traits of vascular plant species that determine their lateral extension patterns. In combination with the different degrees of decomposability of litter derived from their spacers, leaves, roots and stems, these clonal traits should determine associated spatial and temporal patterns in soil organic matter accumulation, nutrient availability and water retention. Conclusions This review gives some concrete pointers as to how to implement this new research agenda through a combination of (1) standardized screening of predominant species in ecosystems for clonal response traits and for effect traits related to carbon, nutrient and water cycling; (2) analysing the overlap between variation in these response traits and effect traits across species; (3) linking spatial and temporal patterns of clonal species in the field to those for soil properties related to carbon, nutrient and water stocks and dynamics; and (4) studying the effects of biotic interactions and feedbacks between resource heterogeneity and clonality. Linking these to environmental changes may help us to better understand and predict the role of clonal plants in modulating impacts of climate change and human activities on ecosystem functions. © 2014 The Author.

Wu Z.,Hunan University | Zhang P.,Hunan University | Zhang P.,Beijing Forestry University | Zeng G.,Hunan University | And 2 more authors.
Journal of Environmental Engineering (United States) | Year: 2012

Humic acid (HA) removal from water with inorganic polyaluminum coagulants is reported in this paper. Polyaluminum chloride (PAC) and three kinds of polyaluminum chloride sulfate (PACS) with a [SO42-]/[Al3+] (S) molar ratio of 0.02, 0.06, and 0.10 were prepared. The coagulation behaviors of these coagulants were investigated in the view of coagulant dosage, initial pH, and aging time. PACS (S=0.06) showed the best HA removal efficiency, and there was no restabilization within a broad effective dosage range. The proper initial pH range was broad and was 4.0-9.0 for PACS (S=0.06). The stability of PACS (S=0.06) reduced with a long aging time, so the proper aging time should not exceed 1 month. The aluminum species distribution, particle mean size, charge neutralization, and infrared spectrum of prepared coagulants were tested. Results showed that SO42-addition promoted the hydrolysis/polymerization of aluminum and reduced the charge neutralization capacity of PACS. Besides charge neutralization, the bridge-aggregation and sweep-flocculation mechanisms may play important roles for HA removal. The coexisting Ca2+ and kaolin slightly promoted the HA removal with polyaluminum coagulants. © 2012 American Society of Civil Engineers.

Zhou H.,Beijing Forestry University | Zhou H.,Jiangxi Academy of science | Cheng F.-Y.,Beijing Forestry University | Wang R.,Beijing Forestry University | And 2 more authors.
PLoS ONE | Year: 2013

Tree peonies are important ornamental plants worldwide, but growing them can be frustrating due to their short and concentrated flowering period. Certain cultivars exhibit a reblooming trait that provides a valuable alternative for extending the flowering period. However, the genetic control of reblooming in tree peonies is not well understood. In this study, we compared the molecular properties and morphology of reblooming and non-reblooming tree peonies during the floral initiation and developmental processes. Using transcriptome sequencing technology, we generated 59,275 and 63,962 unigenes with a mean size of 698 bp and 699 bp from the two types of tree peonies, respectively, and identified eight differentially expressed genes that are involved in the floral pathways of Arabidopsis thaliana. These differentially regulated genes were verified through a detailed analysis of their expression pattern during the floral process by real time RT-PCR. From this combined analysis, we identified four genes, PsFT, PsVIN3, PsCO and PsGA20OX, which likely play important roles in the regulation of the reblooming process in tree peonies. These data constitute a valuable resource for the discovery of genes involved in flowering time and insights into the molecular mechanism of flowering to further accelerate the breeding of tree peonies and other perennial woody plants. © 2013 Zhou et al.

Li Y.,Beijing Forestry University | Lin J.,Beijing Forestry University | Xu Y.,China Agricultural University
Nongye Jixie Xuebao/Transactions of the Chinese Society of Agricultural Machinery | Year: 2011

The simulative study with discrete element method for the cone penetration into the sandy soil was investigated. The results of the simulations and the tests are in good agreement, and the friction on the cone side surface has little influence on the penetration resistance. The conclusion of DEM shows that the strong force chain is located at the cone tip, where the directions of particle velocities are in disorder, while the particles in other place are almost stabile. The penetration resistance increased as the increase of penetration depth, and the normal pressure on the side wall of the soil bin. However, the penetration velocity has little influence on the penetration resistance.

Fan K.,Beihang University | Yang X.,Beihang University | Liu J.,Beijing Forestry University | Rong L.,Beihang University
RSC Advances | Year: 2015

In order to assess the La effect on reducing carbonaceous deposition (coke) on catalysts for the hydrocracking of Jatropha oil, NiW/nHA, NiW/Al2O3 and NiW/HY catalysts modified with loaded La were synthesized and studied. The catalysts were characterized by N2 adsorption-desorption, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption of ammonia (NH3-TPD), temperature programmed desorption of hydrogen (TPD-Hads), and temperature-programmed desorption of carbon dioxide (CO2-TPD). The species and the amount of coke on the hydrocracking catalyst were measured by Fourier transform infrared (FT-IR) spectroscopy, solid state 13C nuclear magnetic resonance (NMR) and thermogravimetric analysis (TGA), demonstrating that the coke was constituted of polyaromatic hydrocarbons and that the La catalyst loading had a very positive effect on coke reduction. The amount of coke on NiW/nHA, NiW/Al2O3 and NiW/HY catalysts decreased respectively by 0.94%, 1.19%, 1.91% after 8 h and 1.66%, 1.89%, 3.78% after 180 h. The catalytic stability and the catalyst lifetime were also improved by La loading. © The Royal Society of Chemistry 2015.

He W.-M.,CAS Institute of Botany | Alpert P.,University of Massachusetts Amherst | Yu F.-H.,CAS Institute of Botany | Yu F.-H.,Beijing Forestry University | And 2 more authors.
Journal of Ecology | Year: 2011

1.The modules of plants experience different levels of resources, and clonal plants can integrate resource heterogeneity. However, no studies have tested whether the benefits of clonal integration depend on patterns of heterogeneity in multiple resources, like high levels of above-ground and below-ground resources in the same patches ('coincident patchiness') or different patches ('reciprocal patchiness'). 2.We hypothesized that the benefits of clonal integration can vary depending on whether patchiness is reciprocal or coincident, and that clonal species experience greater benefits from integration when qualitative patterns of resource heterogeneity are more like those likely to occur in their habitats. To test these hypotheses, we grew pairs of connected ramets of Cynodon dactylon and Potentilla reptans under high and low levels of light and of water and soil nutrients, and measured the growth and physiological traits of the plants. 3.Consistent with the hypotheses, connection between ramets in contrasting patches increased final dry mass of Cynodon by 30% compared with connection between ramets within the same type of patch when resource patchiness was coincident, whereas connection decreased mass by 60% when patchiness was reciprocal. Inconsistent with the hypotheses, between-patch connection increased mass of Potentilla by 70% over within-patch connection whether patchiness was reciprocal or coincident; although the species did grow accumulate more mass when patchiness was reciprocal. 4.In Cynodon, treatments had little effect on allocation of mass to roots or specific leaf area; analysis of mass of ramets within pairs suggested that constraints on translocation may have underlain differential effects of reciprocal and coincident patchiness on performance. In Potentilla, treatments affected all measured characteristics, suggesting a higher degree of clonal integration that may have allowed clones to benefit strongly from integration regardless of pattern of resource patchiness. 5.Synthesis. The ability of some plant species to benefit from clonal integration can depend strongly on whether resource heterogeneity is coincident or reciprocal, while other species may benefit equally from integration under both resource patterns. Our results provide an initial indication that the ecological range of some clonal species may be linked to patterns of resource patchiness via traits of clonal integration. Published 2011. This article is a US Government work and is in the public domain in the USA. Journal of Ecology © 2011 British Ecological Society.

Li S.-L.,CAS Institute of Botany | Li S.-L.,University Utrecht | Li S.-L.,University of Chinese Academy of Sciences | Yu F.-H.,Beijing Forestry University | And 3 more authors.
Journal of Ecology | Year: 2011

Maintaining viable populations in different habitats requires physiological, morphological and demographic adaptations of plants. In sandland environments, plants experience substantial variation in growing conditions during the dune fixation process, with high sand mobility in early stages and denser vegetation cover in later stages. We studied the changes in demography of a dominant shrub, Artemisia ordosica, at three stages of dune fixation: semi-fixed dunes, fixed dunes and fixed dunes covered with microbiotic crust. Demographic data from three annual censuses were used to parameterize integral projection models (IPMs) to conduct comparative demographic analyses. Plant growth and reproduction decreased strongly as dunes became more fixed. Shrinkage in plant height occurred very frequently, particularly in the fixed dunes with microbiotic crust. Population growth rate (λ) declined substantially with dune fixation: from rapid expansion in semi-fixed dunes (λ=1.35-1.09) to moderate decline in fixed dunes with microbiotic crust (λ=0.94-0.89). Elasticity analysis revealed that survival was a key vital rate for population growth in all habitats. Growth and fecundity were of higher importance in the semi-fixed habitat than in the other two habitats where shrinkage became an important factor determining λ. Seedlings and small plants were critical for population growth in semi-fixed dunes, whereas moderate to large-sized plants were most important in the other habitats. Results of life table response experiments showed that the observed strong decrease in λ during dune fixation was mainly caused by reduction in fecundity, but with additional and considerable contributions from reduced plant growth and increased occurrence of shrinkage. Thus, populations in semi-fixed dunes are able to expand rapidly due to a much higher fecundity compared to those in other habitats. Synthesis. Artemisia ordosica adopts different life history strategies along the dune fixation process. Fast expansion in semi-fixed dunes is enabled by high seed production and effective recruitment, while populations at later dune fixation stages are maintained through frequent plant shrinkage. Integral projection models are highly appropriate tools for analysing such life history changes as they are based on statistical comparisons of vital rates across habitats. © 2011 The Authors. Journal of Ecology © 2011 British Ecological Society.

Xie L.,Beijing Forestry University | Li L.-Q.,CAS Institute of Botany
Plant Systematics and Evolution | Year: 2012

Clematis s. l. (including Archiclematis and Naravelia) is a genus of approximately 300 species with cosmopolitan distribution. The diversity of its pollen was surveyed in 162 taxa belonging to all infrageneric groups of Clematis s. l. Pollen morphology was investigated by use of scanning electron microscopy to identify useful characters, test taxonomic and systematic hypotheses, and elucidate pollen character evolution on the basis of the molecular phylogeny. Clematis pollen is small to medium (14. 8-32. 1 μm × 14. 2-28. 7 μm), oblate to prolate (P/E = 0. 9-1. 4) in shape. The apertures may be tricolpate and pantoporate sometimes with 4-zonocolpate and pantocolpate pollen grains as transitional forms. The tricolpate pollen grains are predominant and occur in all the sections of the genus, whereas pantoporate pollen grains can be found in sect. Tubulosae, sect. Viorna, sect. Viticella, and Naravelia only. Phylogenetic mapping of aperture types reveals that the pantoporate pollen type may be the apomorphy in the genus and evolved several times. The surface ornamentation in all taxa studied is similar and characterized by microechinae evenly distributed on the microperforate tectum. The size and density of spinules on the tectum vary greatly but successive in the whole genus. According to the character syndromes of the ornamentation, separating sect. Brachiata from sect. Meclatis is supported. Though pollen morphology may contribute to investigation of problematic taxa, the taxonomic value of pollen morphology is limited at the species level. © 2012 Springer-Verlag.

Xie L.,Beijing Forestry University | Yang Y.,CAS Institute of Botany
International Journal of Plant Sciences | Year: 2012

Ammopiptanthus is the only broad-leaved evergreen angiosperm genus in the deserts of eastern central Asia. Evolutionary history of Ammopiptanthus was examined by means of phylogenetic and molecular dating analyses with a more extensive sampling than ever to shed light on the origin of the genus and the eastern central Asian flora. MatK and nrITS sequences were analyzed using parsimony and Bayesian methods. Divergence time of Ammopiptanthus was estimated using Bayesian dating analyses with relaxed clock model. Both the nrITS-based phylogeny and the matK-based phylogeny gave similar results that Ammopiptanthus is monophyletic and sister to a clade including Sophora and Ammodendron. Low levels of molecular variation were detected in both the plastid and the nuclear DNA regions within Ammopiptanthus. The two species of the genus cannot be distinguished by the analyses. The stem age of Ammopiptanthus was estimated to be 19.6 million years (Myr; 95% highest posterior density [HPD]: 11.2-28.2 Myr) by the matK data and 21.8 Myr (95% HPD: 13.8-30.0 Myr) by nrITS analysis. The estimated divergence time favors the hypothesis that Ammopiptanthus is a Tertiary relic genus descended from the broad-leaved evergreen Tethyan flora. With increasingly intensified aridification of the region, Ammopiptanthus, together with other charact eristic generain the modern desert flora of eastern central Asia, was able to successfully establish themselves because of high ecological capacities in adaptation to local environments and have persisted for a long time. © 2012 by The University of Chicago.

Han Y.,Beijing Forestry University | Fan Y.,Chinese Academy of Agricultural Sciences | Yang P.,China Agricultural University | Wang X.,CAS Research Center for Eco Environmental Sciences | And 4 more authors.
Geoderma | Year: 2014

This study provides a new understanding to sources of nitrogen (N), and may serve as a foundation for further exploration of anthropogenic effects on N inputs. Estimation of net anthropogenic nitrogen inputs (NANI) was based on an inventory of atmospheric N deposition, N fertilizer use, N in human food and animal feed, seeding N and N fixation. This study took a step forward to calculate NANI in detail on a regional scale, and analyzed its temporal variations and geographic differences. Over the past 28years, NANI increased significantly in Mainland China, from 2360kgNkm-2yr-1 to 5013kgNkm-2yr-1. On a geographical basis, NANI was higher in southeast where China's eight major watersheds are located than in northwest, and the largest NANI, 26160kgNkm-2yr-1, appeared in Shanghai. The administrative regions corresponding to Haihe watershed, Huaihe watershed and Tai lake watershed have the largest NANI. N input of fertilizer is the largest source of NANI, followed by atmospheric N deposition and N fixation. The primary factor in relation to the change in NANI is total population density, followed by cultivated land area and total grain yield. In those densely populated large cities and watersheds, reasonably allocating the social resources to reduce the existing population density is the most effective way to address the problem of high N inputs, while in those agriculture-dominated regions and watersheds, the most effective way for reducing NANI is to improve fertilizer utilization efficiency in agriculture. © 2013 Elsevier B.V.

Liu Y.-J.,CAS Institute of Botany | Liu Y.-J.,University of Chinese Academy of Sciences | Han X.-M.,Beijing Forestry University | Ren L.-L.,CAS Institute of Botany | And 2 more authors.
Plant Physiology | Year: 2013

Plant glutathione S-transferases (GSTs) are multifunctional proteins encoded by a large gene family that play major roles in the detoxification of xenobiotics and oxidative stress metabolism. To date, studies on the GST gene family have focused mainly on vascular plants (particularly agricultural plants). In contrast, little information is available on the molecular characteristics of this large gene family in nonvascular plants. In addition, the evolutionary patterns of this family in land plants remain unclear. In this study, we identified 37 GST genes from the whole genome of the moss Physcomitrella patens, a nonvascular representative of early land plants. The 37 P. patens GSTs were divided into 10 classes, including two new classes (hemerythrin and iota). However, no tau GSTs were identified, which represent the largest class among vascular plants. P. patens GST gene family members showed extensive functional divergence in their gene structures, gene expression responses to abiotic stressors, enzymatic characteristics, and the subcellular locations of the encoded proteins. A joint phylogenetic analysis of GSTs from P. patens and other higher vascular plants showed that different class GSTs had distinct duplication patterns during the evolution of land plants. By examining multiple characteristics, this study revealed complex patterns of evolutionary divergence among the GST gene family in land plants.

Ji R.,China Agricultural University | Li D.,China Agricultural University | Chen L.,Beijing Forestry University | Yang W.,China Agricultural University
Mathematical and Computer Modelling | Year: 2010

Foreign fibers in cotton have seriously affected the quality of cotton products. The classification and identification of foreign fibers in cotton is the foundation of cotton foreign fiber automated inspection. The paper takes the typical cotton foreign fibers in China's textile enterprises as the research object, and acquires the images under simulated actual cotton processing. The various classification features are calculated and analyzed. The results show that aspect ratio, roundness, duty cycle and I 1 are the effective features for classifying various foreign fibers. The paper puts forward a classifier of cotton foreign fibers based on a support vector machine. A Decision Tree Support Vector Machine (DTSVM) can not only avoid the non-separated region, but also improve the training speed while the training sample number gradually decreases, going through the decision tree. The DTSVM is to be used to identify the sorts of common foreign fibers in cotton. The experimental data set shows that the rates of identifying different kinds of foreign fibers are greater than 92% using the proposed DTSVM. © 2009.

You W.,Beihang University | You W.,Beijing Forestry University | Liu L.,Beihang University | Xia M.,Santa Clara University | Lv C.,Beihang University
Electronic Commerce Research and Applications | Year: 2011

In consumer-to-consumer (C2C) markets, sellers can manipulate their reputation by employing a large number of puppet buyers who offer positive feedback on fake transactions. We present a conceptual framework to identify the characteristics of collusive transactions based on the homo economicus assumption. We hypothesize that transaction-related indicators including price, frequency, comment, and connectedness to the transaction network, and individual-related indicators including reputation and age can be used to identify collusive transactions. The model is empirically tested using a dataset from Taobao, the largest C2C market in China. The results show that the proposed indicators are effective in identifying collusive traders. © 2011 Elsevier B.V. All rights reserved.

Wen Y.-Q.,China Agricultural University | He F.,China Agricultural University | Zhu B.-Q.,Beijing Forestry University | Lan Y.-B.,China Agricultural University | And 5 more authors.
Food Chemistry | Year: 2014

This paper reports the occurrence of both free and glycosidically bound aroma compounds in three sweet cherry cultivars ('Hongdeng', 'Hongyan' and 'Rainier'), with 97 compounds being identified in the three cultivars. The major free volatile compounds found were hexanal, (E)-2-hexenal, (E)-2-hexen-1-ol, benzyl alcohol and benzaldehyde. The major bound volatile compounds found were benzyl alcohol, geraniol, 2-phenylethanol. Also 4-vinylphenol was found in cherry fruit for the first time, and has a relatively high concentration of the glycosidically-bound form in 'Rainier'. Odour activity values (OAVs) were determined for both free and bound volatiles, with 18 compounds having an OAV above 1. The highest OAVs for three cultivars were (E)-β-ionone, hexanal, decanal and (E)-2-hexenal with the highest being over 800 for (E)-β-ionone in 'Honyang'. From these results, it was concluded that the aroma compounds present were similar in all three cultivars, but there was significant variation found in their levels and hence contribution to the aroma of these cultivars. © 2013 Elsevier Ltd. All rights reserved.

Liu H.-M.,South China University of Technology | Liu H.-M.,University of South China | Xie X.-A.,University of South China | Ren J.-L.,South China University of Technology | And 2 more authors.
Industrial Crops and Products | Year: 2012

The objective of this work was to develop appropriate reaction pathways to explain the liquefaction behavior of cornstalk in sub- and super-critical ethanol. This reaction system was divided into gas lump, water-soluble oil lump, heavy oil lump, volatile organic compounds lump and residue lump based on the characteristics of cornstalk and liquefaction products, and the residue was further separated into carbon, hydrogen, oxygen and nitrogen. Results showed that the reversible reaction between heavy oil and volatile organic compounds occurred in the liquefaction process, and the decrease in the water-soluble oil yield was mainly attributed to the conversion of water-soluble oil to gas in the sub- and super-critical ethanol. The GC/MS analysis showed that the volatile organic compounds, water-soluble oil and heavy oil comprised a mixture of organic compounds of 6-10, 3-12 and 8-20 carbons, respectively, which mainly included esters, phenols, acids, furans and their derivatives. © 2011 Elsevier B.V.

Cao S.,Beijing Forestry University | Chen L.,CAS Institute of Soil and Water Conservation | Shankman D.,University of Alabama | Wang C.,Beijing Forestry University | And 2 more authors.
Earth-Science Reviews | Year: 2011

Afforestation is a primary tool for controlling desertification and soil erosion in China. Large-scale afforestation, however, has complex and poorly understood consequences for the structure and composition of future ecosystems. Here, we discuss the potential links between China's historical large-scale afforestation practices and the program's effects on environmental restoration in arid and semi-arid regions in northern China based on a review of data from published papers, and offer recommendations to overcome the shortcomings of current environmental policy. Although afforestation is potentially an important approach for environmental restoration, current Chinese policy has not been tailored to local environmental conditions, leading to the use of inappropriate species and an overemphasis on tree and shrub planting, thereby compromising the ability to achieve environmental policy goals. China's huge investment to increase forest cover seems likely to exacerbate environmental degradation in environmentally fragile areas because it has ignored climate, pedological, hydrological, and landscape factors that would make a site unsuitable for afforestation. This has, in many cases, led to the deterioration of soil ecosystems and decreased vegetation cover, and has exacerbated water shortages. Large-scale and long-term research is urgently needed to provide information that supports a more effective and flexible environmental restoration policy. © 2010 Elsevier B.V.

Lu P.-F.,Beijing Forestry University | Qiao H.-L.,Peking Union Medical College | Luo Y.-Q.,Beijing Forestry University
Zeitschrift fur Naturforschung - Section C Journal of Biosciences | Year: 2013

The legume pod borer, Maruca vitrata (Lepidoptera: Crambidae; syn. M. testulalis), is a serious pantropical insect pest of grain legumes. Comparative studies of M. vitrata female sex pheromone components in two different geographic populations in China, Wuhan and Huazhou, confirmed that (E,E)-10,12-hexadecadienal (E10,E12 - 16:Ald) and (E)-10-hexadecenal (E10 - 16:Ald) were present in variable ratios in all pheromone gland extracts of both populations. (E,E)-10,12-hexadecadienol (E10,E12 - 16:OH) was always detected in minor amounts using polar DB-WAX columns, but was never detected using medium-polar DB-17 columns for the two populations. E10 - 16:OH was not found in any of the M. vitrata sex pheromone gland extracts. The average ratios of E10 - 16:Ald, E10,E12 - 16:Ald, and E10,E12 - 16:OH in the pheromone gland extracts of populations from Wuhan and Huazhou were 79.5:100:12.1 and 10.3:100:0.7, respectively. Electrophysiological testing suggested that E10,E12 - 16:Ald elicited the highest male electroantennography (EAG) response, followed by E10,E12 - 16:OH and E10 - 16:Ald. Field-trapping tests with single synthetic sex pheromone lures showed that E10,E12 - 16:OH alone could not attract males, whereas E10,E12 - 16:Ald or E10 - 16:Ald alone attracted few males. Wuhan and Huazhou males were most attracted by lures containing E10 - 16:Ald + E10,E12 - 16:Ald + E10,E12 - 16:OH in doses of (80 + 100 + 10) μg and (10 + 100 + 10) μg, respectively, per vial. Males could discriminate between the blends that were most attractive to their own geographic population and those that were most attractive to the reference population. Our findings suggest that geographic variation exists in the sex pheromone system of M. vitrata in China. The results are discussed with regard to the mechanisms underlying the sex pheromone variation. © 2013 Verlag der Zeitschrift für Naturforschung, Tübingen.

Li W.,Beijing Forestry University | Wang X.,CAS Institute of Botany | Li Y.,Beijing Forestry University
PLoS ONE | Year: 2011

Coniferous seed orchards require a long period from initial seed harvest to stable seed production. Differential reproductive success and asynchrony are among the main factors for orchard crops year-to-year variation in terms of parental gametic contribution and ultimately the genetic gain. It is fundamental in both making predictions about the genetic composition of the seed crop and decisions about orchard roguing and improved seed orchard establishment. In this paper, a primary Chinese pine seed orchard with 49 clones is investigated for stability, variation and correlation analysis of factors which influence genetic quality of the seed lots from initial seed harvest to the stable seed production over a 12 years span. Results indicated that the reproductive synchrony index of pollen shedding has shown to be higher than that of the strobili receptivity, and both can be drastically influenced by the ambient climate factors. Reproductive synchrony index of the clones has certain relative stability and it could be used as an indication of the seed orchard status during maturity stage; clones in the studied orchard have shown extreme differences in terms of the gametic and genetic contribution to the seed crop at the orchard's early production phase specifically when they severe as either female or male parents. Those differences are closely related to clonal sex tendency at the time of orchard's initial reproduction. Clonal gamete contribution as male and female parent often has a negative correlation. Clone utilization as pollen, seed or both pollen and seed donors should consider the role it would play in the seed crop; due to numerous factors influencing on the mating system in seed orchards, clonal genetic contribution as male parent is uncertain, and it has major influence on the genetic composition in the seed orchard during the initial reproductive and seed production phase. © 2011 Li et al.

Nie P.,Shandong Agricultural University | Wang X.,Beijing Forestry University | Hu L.,China Agricultural University | Zhang H.,CAS Institute of Botany | And 3 more authors.
Plant and Cell Physiology | Year: 2010

Phloem unloading plays a pivotal part in photoassimilate transport and partitioning into sink organs. However, it remains unclear whether the unloading pathway alters to adapt to developmental transitions in sinks, especially in fleshy fruits accumulating a high level of soluble sugars. Using a combination of electron microscopy, transport of the phloem-mobile symplasmic tracer carboxyfluorescein and assays of acid invertase, the pathway of unloading was investigated in different varieties of Chinese jujube fruit (Zizyphus jujuba Mill. cv Dongzao and Lizao). Structural investigation showed that the sieve elementcompanion-cell complex of bundles feeding the fruit flesh is symplasmically connected with surrounding parenchyma cells at the middle stage, and isolated during the early and late stages. Numerous plasmodesmata are present between phloem parenchyma cells and flesh cells throughout fruit development. Confocal laser scanning images of carboxyfluorescein unloading showed that the dye remained confined to the phloem strands during the early and late stages of fruit development, whereas it was released from the functional phloem at the middle stage. The levels of both the expression and activities of cell wall acid invertase and soluble acid invertase varied in an inverse pattern relative to fruit development. These results provided clear evidence for the predominance of an apoplasmic phloem unloading pathway interrupted with a symplasmic pathway and simultaneous symplasmic and apoplasmic unloading pathways in post-phloem transport during fruit development. Similar unloading pathways were obtained in different varieties of jujube fruit. The mechanisms and significance of the adaptive switch in the phloem-unloading pathway during fruit development were discussed. © 2010 The Author.

Shi J.,Beijing Forestry University | Shi J.,Central European University | Liu J.,Beijing Forestry University | Pinter L.,Central European University | Pinter L.,International Institute for Sustainable Development
Hydrology and Earth System Sciences | Year: 2014

China has dramatically increased its virtual water import over recent years. Many studies have focused on the quantity of traded virtual water, but very few go into analysing geographic distribution and the properties of China's virtual water trade network. This paper provides a calculation and analysis of the crop-related virtual water trade network of China based on 27 major primary crops between 1986 and 2009. The results show that China is a net importer of virtual water from water-abundant areas of North America and South America, and a net virtual water exporter to water-stressed areas of Asia, Africa, and Europe. Virtual water import is far larger than virtual water export, and in both import and export a small number of trade partners control the supply chain. Grain crops are the major contributors to virtual water trade, and among grain crops, soybeans, mostly imported from the US, Brazil and Argentina, are the most significant. In order to mitigate water scarcity and secure the food supply, virtual water should actively be incorporated into national water management strategies. And the sources of virtual water import need to be further diversified to reduce supply chain risks and increase resilience. © 2014 Author(s).

Guo W.,Beijing Forestry University | Song Y.-B.,CAS Institute of Botany | Yu F.-H.,Beijing Forestry University
PLoS ONE | Year: 2011

Spatial heterogeneity in resource supply is common and responses to heterogeneous resource supply have been extensively documented in clonal angiosperms but not in pteridophytes. To test the hypotheses that clonal integration can modify responses of pteridophytes to heterogeneous resource supply and the integration effect is larger at higher patch contrast, we conducted a field experiment with three homogeneous and two heterogeneous light treatments on the rhizomatous, understory fern Diplopterygium glaucum in an evergreen broad-leaved forest in East China. In homogeneous treatments, all D. glaucum ramets in 1.5 m×1.5 m units were subjected to 10, 40 and 100% natural light, respectively. In the heterogeneous treatment of low patch contrast, ramets in the central 0.5 m×0.5 m plots of the units were subjected to 40% natural light and their interconnected ramets in the surrounding area of the units to 100%; in the heterogeneous treatment of high patch contrast, ramets in the central plots were subjected to 10% natural light and those in the surrounding area to 100%. In the homogeneous treatments, biomass and number of living ramets in the central plots decreased and number of dead ramets increased with decreasing light supply. At low contrast heterogeneous light supply did not affect performance or biomass allocation of D. glaucum in the central plots, but at high contrast it increased lamina biomass and number of living ramets older than annual and modified biomass allocation to lamina and rhizome. Thus, clonal integration can affect responses of understory ferns to heterogeneous light supply and ramets in low light patches can be supported by those in high light. The results also suggest that effects of clonal integration depend on the degree of patch contrast and a significant integration effect may be found only under a relatively high patch contrast. © 2011 Guo et al.

Hu L.,China Agricultural University | Sun H.,China Agricultural University | Li R.,China Agricultural University | Zhang L.,Beijing Forestry University | And 3 more authors.
Plant, Cell and Environment | Year: 2011

The phloem unloading pathway remains unclear in fruits of Cucurbitaceae, a classical stachyose-transporting species with bicollateral phloem. Using a combination of electron microscopy, transport of phloem-mobile symplasmic tracer carboxyfluorescein, assays of acid invertase and sucrose transporter, and [ 14C]sugar uptake, the phloem unloading pathway was studied in cucumber (Cucumis sativus) fruit from anthesis to the marketable maturing stage. Structural investigations showed that the sieve element-companion cell (SE-CC) complex of the vascular bundles feeding fruit flesh is apparently symplasmically restricted. Imaging of carboxyfluorescein unloading showed that the dye remained confined to the phloem strands of the vascular bundles in the whole fruit throughout the stages examined. A 37kDa acid invertase was located predominantly in the cell walls of SE-CC complexes and parenchyma cells. Studies of [ 14C]sugar uptake suggested that energy-driven transporters may be functional in sugar trans-membrane transport within symplasmically restricted SE-CC complex, which was further confirmed by the existence of a functional plasma membrane sucrose transporter (CsSUT4) in cucumber fruit. These data provide a clear evidence for an apoplasmic phloem unloading pathway in cucumber fruit. A presumption that putative raffinose or stachyose transporters may be involved in soluble sugars unloading was discussed. © 2011 Blackwell Publishing Ltd.

Niu S.-H.,Beijing Forestry University | Li Z.-X.,Beijing Forestry University | Yuan H.-W.,Beijing Forestry University | Chen X.-Y.,Beijing Forestry University | And 3 more authors.
BMC Genomics | Year: 2013

Background: The Chinese pine (Pinus tabuliformis) is an indigenous conifer species in northern China but is relatively underdeveloped as a genomic resource; thus, limiting gene discovery and breeding. Large-scale transcriptome data were obtained using a next-generation sequencing platform to compensate for the lack of P. tabuliformis genomic information.Results: The increasing amount of transcriptome data on Pinus provides an excellent resource for multi-gene phylogenetic analysis and studies on how conserved genes and functions are maintained in the face of species divergence. The first P. tabuliformis transcriptome from a normalised cDNA library of multiple tissues and individuals was sequenced in a full 454 GS-FLX run, producing 911,302 sequencing reads. The high quality overlapping expressed sequence tags (ESTs) were assembled into 46,584 putative transcripts, and more than 700 SSRs and 92,000 SNPs/InDels were characterised. Comparative analysis of the transcriptome of six conifer species yielded 191 orthologues, from which we inferred a phylogenetic tree, evolutionary patterns and calculated rates of gene diversion. We also identified 938 fast evolving sequences that may be useful for identifying genes that perhaps evolved in response to positive selection and might be responsible for speciation in the Pinus lineage.Conclusions: A large collection of high-quality ESTs was obtained, de novo assembled and characterised, which represents a dramatic expansion of the current transcript catalogues of P. tabuliformis and which will gradually be applied in breeding programs of P. tabuliformis. Furthermore, these data will facilitate future studies of the comparative genomics of P. tabuliformis and other related species. © 2013 Niu et al.; licensee BioMed Central Ltd.

Cao S.,Beijing Forestry University | Wang X.,China Agricultural University | Song Y.,China Agricultural University | Chen L.,CAS Institute of Soil and Water Conservation | Feng Q.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute
Ecological Economics | Year: 2010

Conservation of the ecological environment presents scientists with a challenging dilemma because the strategy often leads to negative impacts on impoverished people in the area affected by the project. To consider this problem, we investigated the implications of China's national and regional policies related to the Natural Forest Conservation Program (NFCP) for poverty in the dryland regions of northern Shaanxi Province. We found that 34.9, 47.0, and 59.8% of farmers, livestock grazers, and forest workers respectively, felt that their livelihoods had been adversely affected by the NFCP due to the ban on logging and grazing imposed by this program, and they perceived additional economic losses because they were not adequately compensated for their economic losses under the program. These perceptions are supported by economic data. In addition, our results showed that the poorer the survey respondent, the greater the likelihood they believed that they had suffered from the implementation of the NFCP. Although Chinese citizens have become more favorable towards environmental conservation efforts, the poorest citizens still need considerable help to make it possible for them to participate in both economic development and environmental restoration. © 2009 Elsevier B.V. All rights reserved.

Dong B.-C.,Beijing Forestry University | Yu G.-L.,CAS Institute of Botany | Guo W.,Beijing Forestry University | Zhang M.-X.,Beijing Forestry University | And 2 more authors.
Evolutionary Ecology | Year: 2010

Disturbance is common in nature and disturbance-caused fragmentation of clones happens frequently in stoloniferous plants. After fragmentation storage in stolon internodes and leaves may enhance survival and growth of stoloniferous plants. We hypothesize that (1) increasing length of the internode attached to the ramet and (2) presence of leaves will increase ramet survival and growth, and that (3) internode positions (before or after the ramet or both) will also play a role. We tested these hypotheses with the stoloniferous, invasive herb Alternanthera philoxeroides. In one experiment, we measured survival and growth of the ramets either without stolon internode (0 cm in length) or attached with internodes of 2, 4, 6 and 8 cm and either with or without leaves. In the other experiment, we measured survival and growth of the ramets attached with a proximal internode (before the ramet), a distal internode (after the ramet) or both. Increasing internode length and presence of leaves significantly increased the survival rate and growth (biomass, leaf area, number of ramets, stolon length and number of leaves) of the A. philoxeroides plants. All growth measures of A. philoxeroides at harvest were larger when the ramets were attached with a distal internode than when they were attached with a proximal internode, but the survival rate was lower. These results support the hypotheses and suggest that storage in stolons and leaves may be of great significance for clonal plants in frequently disturbed habitats and may contribute greatly to the invasiveness of A. philoxeroides. © 2010 Springer Science+Business Media B.V.

Li J.,Fudan University | Xia R.,Fudan University | McDowall R.M.,NIWA - National Institute of Water and Atmospheric Research | Lopez J.A.,University of Alaska Fairbanks | And 3 more authors.
Molecular Phylogenetics and Evolution | Year: 2010

This study examines phylogenetic placement of the enigmatic Western Australian Lepidogalaxias, and extends previous studies by including eight new taxa to enable re-examination phylogenetic relationships of lower euteleostean fishes at the ordinal level, based on mitochondrial genomes from 39 ingroup taxa and 17 outgroups. Our results suggest that Lepidogalaxias occupies a basal position among all euteleosts, in contrast with earlier hypotheses that variously suggested a closer relationship to esocid fishes, or to the galaxiid Lovettia. In addition our evidence shows that Osmeriformes should be restricted Retropinnidae, Osmeridae, Plecoglossidae and Salangidae. This reduced Osmeriformes is supported in our results as the sister group of Stomiiformes. Galaxiidae, which is often closely linked to Osmeriformes, emerges as sister group of a combined Osmeriformes, Stomiiformes, Salmoniformes, Esociformes and Argentiformes, and we give Galaxiiformes the rank of order to include all remaining galaxioid fishes (Galaxias and allied taxa, Aplochiton and Lovettia). Our results also support a sister group relationship between Salmoniformes and Esociformes, which are together the sister group of Argentiniformes. © 2010 Elsevier Inc.

Xu S.,Chinese Institute of Scientific and Technical Information | An X.,Beijing Forestry University | Qiao X.,Chinese Institute of Scientific and Technical Information | Zhu L.,Chinese Institute of Scientific and Technical Information | Li L.,China Agricultural University
Pattern Recognition Letters | Year: 2013

Multi-output regression aims at learning a mapping from a multivariate input feature space to a multivariate output space. Despite its potential usefulness, the standard formulation of the least-squares support vector regression machine (LS-SVR) cannot cope with the multi-output case. The usual procedure is to train multiple independent LS-SVR, thus disregarding the underlying (potentially nonlinear) cross relatedness among different outputs. To address this problem, inspired by the multi-task learning methods, this study proposes a novel approach, Multi-output LS-SVR (MLS-SVR), in multi-output setting. Furthermore, a more efficient training algorithm is also given. Finally, extensive experimental results validate the effectiveness of the proposed approach. © 2013 Elsevier Ltd. All rights reserved.

Zhang T.,Beijing Forestry University | Bu M.-d.,China Agricultural University | Geng W.,China Agricultural University
Chinese Journal of Ecology | Year: 2012

In order to make clear the discharged amount, pollution status, and biogas-producing potential of the livestock and poultry excrements in China, the main parameters for estimation were ascertained based on relevant references, and the discharged amount, pollutant contents, and farmland loading of the excrements in 2009 were estimated, according to the related statistic data. The farmland lading of the excrements nitrogen and phosphorus was assessed by alarming values and classification grades, and the biogas-producing potential of the excrements was predicted. In 2009, the discharged amount of the excrements in China was 330 million tons, with 72. 7 million tons of BOD and 80.4 million tons of DOD, and the average farmland loading of the excrements was 26. 8 kg · hm-2, with the nitrogen and phosphorus loading being 158. 42 kg · hm-2 and 47. 92 kg · hm-2, respectively. The alarming and classification grading showed that the livestock and poultry breeding industry in China had little effects on the environment in pastoral areas, but the manure nitrogen caused varying degrees of environmental pollution in rural areas except those in Shanxi and Heilongjiang provinces, and the manure phosphorus pollution existed in all rural areas. The biogas-producing potential of the excrements was 1.2×1011 m3, and that in large- and medium-sized livestock and poultry breeding farms was responsible for 2. 4×1010 m3, corresponding to about 1. 35×1010 m3 of natural gas. To fully use the excrements for biogas production would be an important way for environmental protection and energy source structural adjustment.

Luo Z.,Beijing Forestry University | Luo Z.,CAS Institute of Botany | Sun O.J.,Beijing Forestry University | Wang E.,CSIRO | And 2 more authors.
Ecosystems | Year: 2010

Ecosystem dynamics and the responses to climate change in mangrove forests are poorly understood. We applied the biogeochemical process model Biome-BGC to simulate the dynamics of net primary productivity (NPP) and leaf area index (LAI) under the present and future climate conditions in mangrove forests in Shenzhen, Zhanjiang, and Qiongshan across the southern coast of China, and in three monocultural mangrove stands of two native species, Avicennia marina and Kandelia obovata, and one exotic species, Sonneratia apetala, in Shenzhen. The soil hydrological process of the model was modified by incorporating a soil water (SW) stress index to account for the impact of the effective SW availability in the coastal wetland. Our modified Biome-BGC well predicted the dynamics of NPP and LAI in the mangrove forests at the study sites. We found that the six mangrove systems differed in sensitivity to variations in the effective SW availability. At the ecosystem level, however, soil salinity alone could not entirely explain the limitation of the effective SW availability on the productivity of mangrove forests. Increasing atmospheric CO2 concentration differentially affected growth of different mangrove species but only had a small impact on NPP (≤7%); whereas a doubling of atmospheric CO2 concentration associated with a 2°C temperature rise would increase NPP by 14-19% across the three geographically separate mangrove forests and by 12% to as much as 68% across the three monocultural mangrove stands. Our simulation analysis indicates that temperature change is more important than increasing CO2 concentration in affecting productivity of mangroves at the ecosystem level, and that different mangrove species differ in sensitivity to increases in temperature and CO2 concentration. © 2010 Springer Science+Business Media, LLC.

Luo Z.,CAS Institute of Botany | Luo Z.,CSIRO | Wang E.,CSIRO | Sun O.J.,Beijing Forestry University
Agriculture, Ecosystems and Environment | Year: 2010

Adopting no-tillage in agro-ecosystems has been widely recommended as a means of enhancing carbon (C) sequestration in soils. However, study results are inconsistent and varying from significant increase to significant decrease. It is unclear whether this variability is caused by environmental, or management factors or by sampling errors and analysis methodology. Using meta-analysis, we assessed the response of soil organic carbon (SOC) to conversion of management practice from conventional tillage (CT) to no-tillage (NT) based on global data from 69 paired-experiments, where soil sampling extended deeper than 40cm. We found that cultivation of natural soils for more than 5 years, on average, resulted in soil C loss of more than 20tha-1, with no significant difference between CT and NT. Conversion from CT to NT changed distribution of C in the soil profile significantly, but did not increase the total SOC except in double cropping systems. After adopting NT, soil C increased by 3.15±2.42tha-1 (mean±95% confidence interval) in the surface 10cm of soil, but declined by 3.30±1.61tha-1 in the 20-40cm soil layer. Overall, adopting NT did not enhance soil total C stock down to 40cm. Increased number of crop species in rotation resulted in less C accumulation in the surface soil and greater C loss in deeper layer. Increased crop frequency seemed to have the opposite effect and significantly increased soil C by 11% in the 0-60cm soil. Neither mean annual temperature and mean annual rainfall nor nitrogen fertilization and duration of adopting NT affected the response of soil C stock to the adoption of NT. Our results highlight that the role of adopting NT in sequestrating C is greatly regulated by cropping systems. Increasing cropping frequency might be a more efficient strategy to sequester C in agro-ecosystems. More information on the effects of increasing crop species and frequency on soil C input and decomposition processes is needed to further our understanding on the potential ability of C sequestration in agricultural soils. © 2010 Elsevier B.V.

Yang H.-L.,Beijing Forestry University | Liu Y.-J.,CAS Institute of Botany | Wang C.-L.,Beijing Forestry University | Zeng Q.-Y.,CAS Institute of Botany
PLoS ONE | Year: 2012

Trehalose-6-phosphate synthase (TPS) plays important roles in trehalose metabolism and signaling. Plant TPS proteins contain both a TPS and a trehalose-6-phosphate phosphatase (TPP) domain, which are coded by a multi-gene family. The plant TPS gene family has been divided into class I and class II. A previous study showed that the Populus, Arabidopsis, and rice genomes have seven class I and 27 class II TPS genes. In this study, we found that all class I TPS genes had 16 introns within the protein-coding region, whereas class II TPS genes had two introns. A significant sequence difference between the two classes of TPS proteins was observed by pairwise sequence comparisons of the 34 TPS proteins. A phylogenetic analysis revealed that at least seven TPS genes were present in the monocot-dicot common ancestor. Segmental duplications contributed significantly to the expansion of this gene family. At least five and three TPS genes were created by segmental duplication events in the Populus and rice genomes, respectively. Both the TPS and TPP domains of 34 TPS genes have evolved under purifying selection, but the selective constraint on the TPP domain was more relaxed than that on the TPS domain. Among 34 TPS genes from Populus, Arabidopsis, and rice, four class I TPS genes (AtTPS1, OsTPS1, PtTPS1, and PtTPS2) were under stronger purifying selection, whereas three Arabidopsis class I TPS genes (AtTPS2, 3, and 4) apparently evolved under relaxed selective constraint. Additionally, a reverse transcription polymerase chain reaction analysis showed the expression divergence of the TPS gene family in Populus, Arabidopsis, and rice under normal growth conditions and in response to stressors. Our findings provide new insights into the mechanisms of gene family expansion and functional evolution. © 2012 Yang et al.

Liu P.,CAS Institute of Botany | Liu P.,Shandong Academy of Agricultural Sciences | Huang J.,CAS Institute of Botany | Sun O.J.,Beijing Forestry University | Han X.,CAS Institute of Botany
Oecologia | Year: 2010

Nitrogen availability is critically important to litter decomposition, especially in arid and semiarid areas where N is limiting. We studied the relative contributions of litter quality and soil N to litter decomposition of two dominant grassland species, Stipa krylovii and Artemisia frigida, in a semiarid typical steppe ecosystem in Inner Mongolia, China. The study had four different rates of N addition (0, 8, 32, and 64 g N m-2 year-1), and litter samples were decomposed under varying site conditions and by litter types. Litter-mixing effects of the two species were also examined. We found that N addition increased litter N concentration and thus enhanced litter decomposition by improving substrate quality. This increase, however, was offset by the negative effect of increased soil N, resulting in a diminished effect of increased soil N availability on in situ litter decomposition. The positive effects of improved litter quality slightly out-performed the negative effects of increased soil N. Our further analysis revealed that the negative effect of increasing soil N on litter decomposition could be partially explained by reduced soil microbial biomass and activity. Decomposition was significantly faster for litters of a two-species mixture than litters of the single species, but the rate of litter decomposition did not differ much between the two species, suggesting that compositional balance, rather than changes in the dominance between Stipa and Artemisia, is more critical for litter decomposition, hence nutrient cycling in this ecosystem. This semiarid steppe ecosystem may become more conservative in nutrient use with switching of dominance from Artemisia to Stipa with increasing soil N, because Stipa has a slower decomposition rate and a higher nutrient retention rate than Artemisia. © Springer-Verlag 2009.

Luo Z.,CAS Institute of Botany | Luo Z.,CSIRO | Luo Z.,University of Chinese Academy of Sciences | Wang E.,CSIRO | Sun O.J.,Beijing Forestry University
Geoderma | Year: 2010

Soil is the largest reservoir of carbon (C) in the terrestrial biosphere and a slight variation in this pool could lead to substantial changes in the atmospheric CO2 concentration, thus impact significantly on the global climate. Cultivation of natural ecosystems has led to marked decline in soil C storage, such that conservation agricultural practices (CAPs) are widely recommended as options to increase soil C storage, thereby mitigating climate change. In this review, we summarise soil C change as a result of cultivation worldwide and in Australia. We then combine the available data to examine the effects of adopting CAPs on soil C dynamics in Australian agro-ecosystems. Finally, we discuss the future research priorities related to soil C dynamics. The available data show that in Australian agro-ecosystems, cultivation has led to C loss for more than 40 years, with a total C loss of approximately 51% in the surface 0.1 m of soil. Adoption of CAPs generally increased soil C. Introducing perennial plants into rotation had the greatest potential to increase soil C by 18% compared with other CAPs. However, the same CAPs could result in different outcomes on soil C under different climate and soil combinations. No consistent trend of increase in soil C was found with the duration of CAP applications, implying that questions remain regarding long-term impact of CAPs. Most of the available data in Australia are limited to the surface 0.1 to 0.3 m of soil. Efforts are needed to investigate soil C change in deeper soil layers in order to understand the impact of crop root growth and various agricultural practices on C distribution in soil profile. Elevated atmospheric CO2 concentration, global warming and rainfall change could all alter the C balance of agricultural soils. Because of the complexity of soil C response to management and environmental factors, a system modelling approach supported by sound experimental data would provide the most effective means to analyse the impact of different management practices and future climate change on soil C dynamics. Crown Copyright © 2009.

Zhang J.,Beijing Forestry University | Wang Z.-T.,Beijing Forestry University | Yu H.-M.,Tsinghua University | Ma Y.,Beijing Forestry University | Ma Y.,Tsinghua University
International Journal of Systematic and Evolutionary Microbiology | Year: 2013

A bacterial strain, designated D75T, was isolated from the rhizosphere soil ofCatalpa speciosa. Phylogenetic analysis based on the complete 16S rRNA gene sequence revealed that strain D75T was a member of the genus Paenibacillus. High levels of 16S rRNA gene sequence similarity were found between strain D75T and Paenibacillus glycanilyticus DS-1T (99.2 %), Paenibacillus xinjiangensis B538T (97.5 %) and Paenibacillus castaneae Ch-32T (97.2 %). The chemotaxonomic properties of strain D75T were consistent with those of the genus Paenibacillus: the cell-wall peptidoglycan type was based on meso-diaminopimelic acid (A1γ), the predominant menaquinone was MK-7, and the major fatty acids were anteiso-C15: 0, iso-C16: 0 and C16: 0. However, levels of DNA-DNA relatedness between strain D75T and P. glycanilyticus NBRC 16618T, P. xinjiangensis DSM 16970T and P. castaneae DSM 19417T were 35, 20 and 18 %, respectively. On the basis of phenotypic and chemotaxonomic analyses, phylogenetic data and DNA-DNA relatedness values, strain D75T is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus catalpae sp. nov. is proposed. The type strain is D75T (= DSM 24714T = CGMCC 1.10784T). © 2013 IUMS.

Chen H.,Beijing Forestry University | Gao Q.,Beijing Forestry University | Li J.,Beijing Forestry University | Lin J.-M.,Tsinghua University
Journal of Photochemistry and Photobiology C: Photochemistry Reviews | Year: 2016

Graphene has attracted considerable attention in multidisciplinary research fields and shown various promising applications due to its unique structure and extraordinary physicochemical properties. This review covers the latest advances in graphene materials-based chemiluminescence (CL) for sensing. Chemiluminescence resonance energy transfer and luminescence quenching of graphene materials are discussed. Graphene materials, such as graphene nanosheets, graphene quantum dots, graphene oxide, and reduced graphene oxide have been employed successfully in CL systems in recent years. Graphene materials can be utilized as catalysts, platforms, and energy acceptors to improve the performance of CL. Possible challenges and future perspective on this topic are also presented. © 2016 Elsevier Ireland Ltd.

Dou X.,Beijing Forestry University | Zhang Y.,Beijing Forestry University | Wang H.,Beijing Forestry University | Wang T.,Tsinghua University | Wang Y.,Beijing Forestry University
Water Research | Year: 2011

In this study, a granular zirconium-iron oxide (GZI) was successfully prepared using the extrusion method, and its defluoridation performance was systematically evaluated. The GZI was composed of amorphous and nano-scale oxide particles. The Zr and Fe were evenly distributed on its surface, with a Zr/Fe molar ratio of ∼2.3. The granular adsorbent was porous with high permeability potential. Moreover, it had excellent mechanical stability and high crushing strength, which ensured less material breakage and mass loss in practical use. In batch tests, the GZI showed a high adsorption capacity of 9.80 mg/g under an equilibrium concentration of 10 mg/L at pH 7.0, which outperformed many other reported granular adsorbents. The GZI performed well over a wide pH range, of 3.5-8.0, and especially well at pH 6.0-8.0, which was the preferred range for actual application. Fluoride adsorption on GZI followed pseudo-second-order kinetics and could be well described by the Freundlich equilibrium model. With the exception of HCO3 -, other co-existing anions and HA did not evidently inhibit fluoride removal by GZI when considering their real concentrations in natural groundwater, which showed that GZI had a high selectivity for fluoride. In column tests using real groundwater as influent, about 370, 239 and 128 bed volumes (BVs) of groundwater were treated before breakthrough was reached under space velocities (SVs) of 0.5, 1 and 3 h-1, respectively. Additionally, the toxicity characteristic leaching procedure (TCLP) results suggested that the spent GZI was inert and could be safely disposed of in landfill. In conclusion, this granular adsorbent showed high potential for fluoride removal from real groundwater, due to its high performance and physical-chemical properties. © 2011 Elsevier Ltd.

Yang J.,Tsinghua University | Yang J.,Beijing Forestry University | Gong C.,Tsinghua University | Shi F.-K.,Tsinghua University | Xie X.-M.,Tsinghua University
Journal of Physical Chemistry B | Year: 2012

This investigation was to study the connections between polymer branch architecture of physical hydrogels and their properties. The bottle-brush-like polymer chains of poly(acrylic acid)-g-poly(ethylene glycol) methyl ether (PAA-g-mPEG) with PAA as backbones and mPEG as branch architecture were synthesized and in situ grafted from silica nanoparticles (SNs) to construct hydrogels cross-linked networks in aqueous solutions. The structural variables to be discussed included molecular weight and molar ratio of branch chains, and new aspects of the formation mechanism of physical hydrogels with branch structure in the absence of organic cross-links were present. The results indicated that the differences of polymer chain architecture could be distinguished via their different interactions that are present by gelation process and mature gel properties, such as gel strength and swelling ratio. The gelation occurred at the critical polymer concentration and molecular weight, respectively, and the inorganic/organic (SNs/PAA-g-mPEG) nanoparticles began to entangle and construct the cross-linking networks afterward. The gel-to-sol transition temperature (Tg-s) and radii of SNs that were encapsulated by polymer chains as a function of time for chains' disentanglement were monitored according to the observation of the dissolution process, and the molecular weight between two consecutive entanglements (Me) was calculated thereafter. This study showed that the introduction of branch chain onto the linear backbone significantly promoted the chain interactions and increased entanglement density, which contributed to the hydrogels' network integrity and rigidity, thus illustrating greater elongation at break and tensile strength than the hydrogels formulated with linear polymer chains. © 2012 American Chemical Society.

Xu B.,Tsinghua University | Sun F.,Tsinghua University | Yang C.,University of Plymouth | Gao D.,Beijing Forestry University | Ren J.,Northwestern Polytechnical University
International Journal of Control | Year: 2011

In this article, the adaptive neural controller in discrete time is investigated for the longitudinal dynamics of a generic hypersonic flight vehicle. The dynamics are decomposed into the altitude subsystem and the velocity subsystem. The altitude subsystem is transformed into the strict-feedback form from which the discrete-time model is derived by the first-order Taylor expansion. The virtual control is designed with nominal feedback and neural network (NN) approximation via back-stepping. Meanwhile, one adaptive NN controller is designed for the velocity subsystem. To avoid the circular construction problem in the practical control, the design of coefficients adopts the upper bound instead of the nominal value. Under the proposed controller, the semiglobal uniform ultimate boundedness stability is guaranteed. The square and step responses are presented in the simulation studies to show the effectiveness of the proposed control approach. © 2011 Taylor & Francis.

Chen Y.,Beijing Forestry University | Fan Y.,Beijing Forestry University | Gao J.,Beijing Forestry University | Li H.,Tsinghua University
Wood Science and Technology | Year: 2012

To investigate the effects of lignin on the discoloration of Black locust (Robinia pseudoacacia) wood during heat treatment, chromatic indexes of the extractive-free wood samples are examined at different moisture contents (MC) under oxygen and nitrogen environment, respectively. The organic acids are produced during heat treatment, resulting in pH decrease in the samples. Components absorbing visible light are formed during heat treatment, and oxygen and moisture contents have obvious effects on the decrease in L*, increase in a*value, yellowness (b*) and total color difference (ΔE) of the samples. It is found that the β-5, C α C β unsaturated bond, the conjugated carbonyl group, quinones structures, α, β-unsaturated ketone and α-C = O in lignin increased after heat treatment. The formation of condensation products, the low-molecular-weight phenolic substances and the oxidation products in lignin result in the increment of the light absorption within the entire visible region. © 2010 Springer-Verlag.

Zheng D.,Beijing Forestry University | Han X.,Beijing Forestry University | An Y.,Beijing Forestry University | Guo H.,Tsinghua University | And 2 more authors.
Plant, Cell and Environment | Year: 2013

The ethylene signalling pathway is closely associated with complex environmental stresses. Previous studies have reported impact of high nitrate (HN) availability on ethylene biosynthesis and regulation of ethylene on nitrate transporter 2.1 (NRT2.1) expression. However, molecular interaction between NRT2.1 transcript levels and the ethylene signalling pathway under nitrate deficiency is still elusive. Here, we report a low nitrate (LN) treatment-induced rapid burst of ethylene production and regulated expression of ethylene signalling components CTR1, EIN3 and EIL1 in wild-type Arabidopsis thaliana (Col-0) seedlings, and enhanced ethylene response reporter EBS:GUS activity in both Col-0 and the ethylene mutants ein3-1eil1-1 and ctr1-1. LN treatment also caused up-regulation of NRT2.1 expression, which was responsible for an enhanced high-affinity nitrate uptake. Comparison of ethylene production and EBS:GUS activity between nrt1.1, nrt2.1 mutants and Col-0 indicated that this up-regulation of NRT2.1 expression caused a positive effect on ethylene biosynthesis and signalling under LN treatment. On the other hand, ethylene down-regulated NRT2.1 expression and reduced the high-affinity nitrate uptake. Together, these findings uncover a negative feedback loop between NRT2.1 expression and ethylene biosynthesis and signalling under nitrate deficiency, which may contribute to finely tuning of plant nitrate acquisition during exploring dynamic soil conditions. Molecular interaction between NRT2.1 transcript levels and the ethylene signaling pathway under nitrate deficiency is still elusive. Here, we report a low nitrate (LN) treatment-induced rapid burst of ethylene production and regulated expression of ethylene signaling components CTR1, EIN3 and EIL1 in wild-type Arabidopsis thaliana (Col-0) seedlings, and enhanced ethylene response reporter EBS:GUS activity in both Col-0 and the ethylene mutants ein3-1eil1-1 and ctr1-1. Comparison of ethylene production and EBS:GUS activity between nrt1.1, nrt2.1 mutants and Col-0 indicated that this up-regulation of NRT2.1 expression caused a positive effect on ethylene biosynthesis/signaling under LN treatment, and ethylene down-regulated NRT2.1 expression and reduced the high-affinity nitrate uptake. Together, these findings uncover a negative feedback loop between NRT2.1 expression and ethylene biosynthesis/signaling under nitrate deficiency, which may contribute to finely tuning of plant nitrate acquisition during exploring dynamic soil conditions. © 2013 John Wiley & Sons Ltd.

Ma Y.,Tsinghua University | Ma Y.,Beijing Forestry University | Yu H.,Tsinghua University
Journal of Industrial Microbiology and Biotechnology | Year: 2012

Tolerance to various stresses is a key phenotype for cell catalysts, which are used widely in bioproduction of diverse valuable chemicals. Using the Rhodococcus ruber TH strain, which exhibits high nitrile hydratase activity, as the target cell catalyst for acrylamide production, we established a method to improve cell tolerance by stably introducing global transcription perturbation. The σ70 gene (sigA) of R. ruber was cloned and randomly mutated. An R. ruber TH3/pNV-sigAM library containing additional sigA mutants was constructed and used for survival selection. The TH3/ M4N1-59 mutant was selected by acrylonitrile/acrylamide double stress and exhibited a 160 %extension of the half-life of nitrile hydratase upon exposure to 40 % acrylamide. A redesigned parDEM gene was introduced to Rhodococcus to accomplish stable inheritance of plasmids. A two-batch acrylonitrile hydration reaction was performed using the engineered cells as a catalyst. Compared to TH3, the acrylamide productivity of TH3/M4N1-59DEM catalysis increased by 27.8 and 37.5 % in the first and second bioreaction batches, respectively. These data suggest a novel method for increasing the bioconversion productivity of target chemicals through sigA mutation of the cell catalyst. © Society for Industrial Microbiology and Biotechnology 2012.

Xu X.,Beijing Forestry University | Luo J.,Tsinghua University | Guo D.,Tsinghua University
Journal of Colloid and Interface Science | Year: 2011

Although nanoparticle impacts on a solid surface always occur in natural or engineering processes and cause extensive investigations, less works have been reported on the nanoparticle-wall collisions in a liquid. In present paper, by considering the inertial effect and the Brownian motion of nanoparticles, a theoretical model was established for calculating the collision frequency between the nanoparticles and the solid surface in a laminar cylindrical liquid jet impacting normally on the solid surface. The analysis showed that the collision frequency grows as the square root of the impacting speed for low impacting speed regime in which the Brownian motion is predominant, whereas increases as the second power of the impacting speed for high impacting speed regime in which the inertial effect is predominant. Meanwhile, an observation system for nanoparticle-wall collisions in a laminar cylindrical liquid jet has been developed. The adsorption of the nanoparticles on the solid surface after collision has also been observed. Because of their lower attractive energy with the solid surface, these adsorbed nanoparticles are easier to be removed by the Fundamental Research Funds for the Central Universities (Grant No. YX2011-9), the Beijing Forestry University Young Scientist Fund (Grant No. 2010BLX08), the hydrodynamic force of the impacting liquid than that deposited on a dry surface. © 2011 Elsevier Inc.

Yang J.,Beijing Forestry University | Han C.-R.,Beijing Forestry University | Duan J.-F.,Beijing Forestry University | Ma M.-G.,Beijing Forestry University | And 4 more authors.
Journal of Materials Chemistry | Year: 2012

A novel series of nanocomposite hydrogels based on cellulose nanocrystals (CNCs) and poly(acrylic acid) (PAA) have been synthesized by in situ free radical polymerization within an aqueous medium. Rheological measurements were applied to monitor the gelation process and results indicated that the gelation took place as monomers (acrylic acid, AA) grafted from the CNC surface and PAA chains entangled to produce flexible CNC-PAA gels. By tailoring the concentration of CNC (C CNC) over a wide range of 0.02-1 wt%, two critical C CNC, C* and C**, were found which corresponded to polymer chains that occurred in overlapping entanglements and promoted conformational rearrangements on the basis of earlier gel precursors, respectively. The formation mechanism of CNC based nanocomposite hydrogels, in which the nanoparticles transformed from the isolated state below C* to the spatially continuous percolation structure above C**, was proposed. The CNC-PAA gels exhibited excellent, composition-dependent mechanical properties, such as a large elongation ratio (>1100%) and high tensile strength (>350 kPa). Transmission electron microscopy (TEM) revealed that the CNCs were surrounded by grafted chains and formed inter-connected network structures, where the CNCs acted as multifunctional cross-links with an average effective functionality of 75. The mechanical measurements indicated that the increase of C CNC led to an increase in the hydrogels viscous characteristics and contributed to the energy dissipating mechanism, which was responsible for CNC-PAA gels excellent flexibility. The swelling and partial dissolution behaviors of the hydrogels were examined, focusing on the effect of C CNC on the gels characteristic partial deswelling and gel-to-sol transition. Some new chain entanglements were formed under concentrated conditions after drying treatment above the glass transition temperature (T g) which was verified by observation of the greater tensile strength and modulus. All the results corresponded to the self-consistent network structure model for CNC-PAA gels. © 2012 The Royal Society of Chemistry.

Wang Q.,Beijing Forestry University | Gao Y.,Beijing Forestry University | Luo J.,Institute of Chemical and Engineering Sciences, Singapore | Zhong Z.,Institute of Chemical and Engineering Sciences, Singapore | And 3 more authors.
RSC Advances | Year: 2013

Due to its layered structure, layered double hydroxides (LDHs) generally prefer to form either "sand rose" or platelet-like morphologies. To the best of our knowledge, nano-sized spherical LDHs have not been previously reported. In this work, we present the first successful synthesis of nano-sized spherical Mg3Al-CO3 LDH using a facile isoelectric point (IEP) method. SEM and TEM analyses confirmed that the size of the nanospheres is very uniform, with an average value of ca. 20 nm. Furthermore, a mesoporous LDH sample composed of the above synthesized uniform nano-spheres can be prepared, and this material showed a H1 type hysteresis loop in the N2 BET analysis. Such mesoporous LDH possesses large mesopores (18 nm) and a high surface area (103 m2 g-1), which we believe make it a promising adsorbent, catalyst, or support material. We demonstrated that its CO2 capture capacity is 0.83 mmol g-1 at 200 °C and 1 atm and it can be further increased up to 1.21 mmol g-1 by doping with 20 wt% K2CO3. © 2013 The Royal Society of Chemistry.

Yang J.,Tsinghua University | Huang C.,Beijing Forestry University | Zhang Z.,Beijing Forestry University | Wang L.,State University of New York at Buffalo
Urban Forestry and Urban Greening | Year: 2014

Information on changes in urban green spaces and the causes of these changes is important for urban planning. In this study the trends of urban green coverage (UGC) between 1990 and 2010 in 30 major Chinese cities were studied using classified Landsat satellite images. Associations between the trends and natural and socio-economic variables were analyzed using the maximum information-based nonparametric exploration method. The results showed that, overall, the studied cities have become greener over the past two decades. Greening in old city districts and expanded built-up areas (BUAs) led to the increase of urban green coverage at a mean annual rate of 1.51%. However rapid urbanization also caused a dramatic turn-over in vegetation covers. On a regional scale, around 46.89% of original vegetation cover was converted to other land cover types. The trends of UGC cannot be attributed to any one of natural or socio-economic variables alone. The combined influences of economic growth, climate change, and urban greening policies are the most likely causes behind the detected trend. One lesson from this study is that the preservation of existing vegetation cover must be a priority in urban greening programs. © 2013 Elsevier GmbH.

Xu X.,Beijing Forestry University | Luo J.,Tsinghua University | Guo D.,Tsinghua University
Soft Matter | Year: 2012

The deposit pattern of drying liquid droplets has a close relationship with the radial-velocity profile along the droplet surface. In this paper, the surface temperature of the droplet is first solved numerically and approximated by a simple analytical form, and an analytical expression for the radial-velocity of the surface flow is then obtained by using the lubrication analysis developed by Hu and Larson. The theoretical analysis indicates that the outward surface flow will be reduced by the thermal Marangoni stress along the surface. When the Marangoni number is below a critical value, MaCrit, all the surface liquid will move outward and a dense, ring-like deposit will be formed. When above MaCrit, a stagnation point, within which the surface flow is inward and beyond which the surface flow is outward, will appear on the droplet surface. In such case, the particles transported to the surface beyond the stagnation point will move to the droplet edge to form the ring deposit, and the others will deposit on the central region of the droplet. Numerical results indicate that the critical Marangoni number decreases in a power law with the contact angle. The theory for the radial-velocity of the surface flow will be helpful to predict and control the deposit patterns from the drying droplets. © 2012 The Royal Society of Chemistry.

Yang J.,Tsinghua University | Yang J.,Beijing Forestry University | Wang X.-P.,Tsinghua University | Xie X.-M.,Tsinghua University
Soft Matter | Year: 2012

This paper introduces a versatile method to synthesize physical hydrogels by silica nanoparticle (SN) surface in situ polymerization. A series of poly(acrylic acid) chains were covalently grafted from the SNs that were treated with γ-methacryloxypropyl trimethoxy silane. The entanglements among the grafted chains constructed the hydrogel networks and the SNs played the role of 'analogous crosslinking points'. The SNs were encapsulated by the grafted polymer chains and formed a 'core-shell' structure. It was found that the molecular weight of the grafted chains and the content and diameter of the SNs affected the hydrogel's properties. In comparison with chemically crosslinked hydrogels, the hybrid hydrogels exhibited excellent mechanical properties and could endure stress as high as 3.16 MPa and an elongation of 440% at a water content of 100 wt%. The gel-sol phenomenon confirmed that this hybrid hydrogel belonged to the physically crosslinked type. © 2012 The Royal Society of Chemistry.

Wang J.,Beijing Forestry University | Huang L.,Beijing Forestry University | Yang R.,Beijing Forestry University | Zhang Z.,Beijing Forestry University | And 5 more authors.
Energy and Environmental Science | Year: 2014

Carbon dioxide (CO2) capture using solid sorbents has been recognized as a very promising technology that has attracted intense attention from both academic and industrial fields in the last decade. It is astonishing that around 2000 papers have been published from 2011 to 2014 alone, which is less than three years after our first review paper in this journal on solid CO2 sorbents was published. In this short period, much progress has been made and the major research focus has more or less changed. Therefore, we feel that it is necessary to give a timely update on solid CO2 capture materials, although we still have to keep some important literature results published in the past years so as to keep the good continuity. We believe this work will benefit researchers working in both academic and industrial areas. In this paper, we still organize the CO2 sorbents according to their working temperatures by classifying them as such: (1) low-temperature (<200 °C), (2) intermediate-temperature (200-400 °C), and (3) high-temperature (>400 °C). Since the sorption capacity, kinetics, recycling stability and cost are important parameters when evaluating a sorbent, these features will be carefully considered and discussed. In addition, due to the huge amounts of cost-effective CO2 sorbents demanded and the importance of waste resources, solid CO2 sorbents prepared from waste resources and their performance are reviewed. Finally, the techno-economic assessments of various CO2 sorbents and technologies in real applications are briefly discussed. © 2014 the Partner Organisations.

Liang K.,University of North Texas | Gao Q.,University of North Texas | Gao Q.,Beijing Forestry University | Shi S.Q.,University of North Texas
Journal of Applied Polymer Science | Year: 2013

In this research, three different types of biocomposites were made from kenaf fiber/soy protein, kenaf fiber/DS 3530, and kenaf fiber/soy protein/DS 3530. Fourier transform infrared spectra of the biocomposites showed that there were chemical reactions among the kenaf fiber, soy flour, and BASF Acrodur resin. The hot-pressing time had a significant effect on the flexural properties and density of both the kenaf fiber/soy flour composites and kenaf fiber/BASF Acrodur resin composites. However, the effect was opposite for the composites from 10 to 20 min of hot pressing. As the hot-pressing time increased, the flexural properties and density increased for the kenaf fiber/soy flour composites and decreased for the other two composites with BASF Acrodur resin. BASF Acrodur resin reduced the hot-pressing time of the biocomposites. With 28 wt % BASF Acrodur resin (on the basis of 100% solid content) as a binder and with the biocomposites hot-pressed for 10 min, the swelling thickness and water absorption of the composites were reduced by 55 and 64%, and the flexural strength and modulus were improved by 72 and 188%, respectively. More simultaneous failures of the fiber and adhesive were observed at the fracture surface of the kenaf fiber/soy flour/BASF Acrodur resin composite. © 2012 Wiley Periodicals, Inc.

Gao D.X.,Beijing Forestry University | Sun Z.Q.,Tsinghua University
Science China Information Sciences | Year: 2011

The main focus of this paper is on designing a T-S fuzzy controller for the hypersonic vehicle. The longitudinal dynamics of the vehicle are studied using time-scale decomposition to reduce the complexity of T-S modeling. The dynamic inversion with PI control technique is applied for the slow dynamics to derive the flight path angle command and throttle setting by taking the pilot altitude and velocity command as its inputs. The T-S fuzzy controller is designed for the fast dynamics to derive the elevator deflection to track the flight path angle command. The discrepancy between the T-S model and real vehicle model is considered by using sliding mode control for the system stability. Simulation results are included to show the effectiveness of the controller. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.

Chen C.,Helmholtz Center for Environmental Research | Hagemann S.,Max Planck Institute for Meteorology | Liu J.,Beijing Forestry University | Liu J.,International Institute For Applied Systems Analysis
Environmental Earth Sciences | Year: 2014

Climate change as a result of the increased greenhouse gas emissions may influence the availability of water resources in many regions on the globe. In the past decades, China has been facing severe shortage of water resources. This study focuses on the assessment of the impact of climate change on both blue and green water resources in ten large river basins in China. The blue and green water resources for these river basins were derived from the terrestrial hydrological fluxes in period 1960–2100, which were simulated with the Max Planck Institute Hydrological Model—MPI-HM. The forcing data for the hydrological model, the precipitation and temperature were obtained from three coupled Atmosphere–Ocean General Circulation Models (GCMs)—ECHAM5, IPSL and CNRM, under A2 and B1 greenhouse gas emission scenarios. The statistical bias correction method was applied on the output from the three GCMs. By using this climate model–hydrology model modeling chain, the impact of climate change on the blue and green water resources was analyzed over the ten Chinese river basins. Here, the projected changes in 2071–2100 are considered relative to 1971–2000. The projected change of monthly mean and annual mean of green water resources show the general increase for all ten river basins; among them, Inland river, Zhemin river and Zhujiang river have larger change signal than other basins. For blue water resources, increases of the annual mean are projected from November to March for Heilongjiang river, Liaohe river and Yellow river, Inland river in Northern China; and decreases are projected for Huaihe river, Zhemin river, Haihe river, Yangzi river, Southwest river, and Zhujiang river basins in Southern China. It is found that climate change has impact on both blue and green water resources over large river basins in China. The sustainable blue water resources management should take into account the different changes in both Northern and Southern China. The results show that a better management of green water resources is of importance for food and ecological securities in the context of global change. © 2014 Springer-Verlag Berlin Heidelberg

Yang J.,Tsinghua University | Chang Y.,Beijing Forestry University | Yan P.,Beijing Forestry University
Atmospheric Pollution Research | Year: 2015

Pollution caused by particles with aerodynamic diameters less than 2.5 μm (PM2.5) is now a major environmental problem in many Asian cities. Planting more trees has been suggested as an unconventional approach to alleviate the problem. In this study, we developed a ranking approach to evaluate the PM2.5removal efficiency, negative impacts on air quality, and the suitability to urban environments of commonly occurring urban tree species. The results showed that the most frequently occurring tree species in global cities were not the best performers in removing PM2.5. Among the ten most frequently occurring tree species, only London plane (Platanus acerifolia (Aiton) Wild.), silver maple (Acer saccharinum L.) and honey locust (Gleditsia triacanthos L.) were ranked above average. However, there is great potential for improving the removal of PM2.5from urban air by using species that have high PM2.5removal efficiency, especially conifer species. Use of conifer species requires choosing the correct gender and matching trees with appropriate sites. The results from this study can assist environmental management agencies in the selection of tree species for urban greening projects focusing on PM2.5control. © Author(s) 2015. This work is distributed under the Creative Commons Attribution 3.0 License.

Zhang C.,Beijing Forestry University | Zhao Y.,Tsinghua University | Zhao X.,Beijing Forestry University | von Gadow K.,University of Gottingen
Silva Fennica | Year: 2012

This contribution identifies species-habitat associations in a temperate forest in north-eastern China, based on the assumption that habitats are spatially autocorrelated and species are spatially aggregated due to limited seed dispersal. The empirical observations were obtained in a large permanent experimental area covering 660 × 320 m. The experimental area was subdivided into four habitat types using multivariate regression tree (MRT) analysis. According to an indicator species analysis, 38 of the 47 studied species were found to be significant indicators of the MRT habitat types. The relationships between species richness and topographic variables were found to be scale-dependent, while the great majority of the species shows distinct habitat-dependence. There are 188 potential species-habitat associations, and 114 of these were significantly positive or negative based on habitat randomization. We identified 139 significant associations using a species randomization. A habitat is not a closed system it may be both, either a sink or a source. Therefore, additional to the randomization, the Poisson Cluster Model (PCM) was applied. PCM considers the spatial autocorrelation of species and habitats, and thus appears to be more realistic than the traditional randomization processes. It identified only 37 associations that were significant. In conclusion, the deviation from the random process, i.e. the high degree of species spatial mingling may be explained by persistent immigration across habitats.

Da T.,Beijing Forestry University | Xu Y.,Hohai University
Ocean and Coastal Management | Year: 2016

“Connectivity” is the core planning strategy that is used to examine the features of functional and structural connections in urban waterfront redevelopment projects. According to SIA point of view, an index system of assessing urban waterfront redevelopment connectivity including 8 evaluation indexes is proposed from the hierarchy of ecological, social functional and contextual connections. In order to evaluate the connectivity of urban waterfront redevelopment, this paper proposes an interactive procedure for multi-attribute decision making under hesitant fuzzy linguistic environment, which allows the experts use several linguistic values to assess the connectivity index. A case study of typical redevelopment projects of Huangpu River Waterfront in Shanghai is analyzed to figure out the difference between landscape-restoration oriented projects and urban-exploitation projects. Theoretical analysis and computational results showed that the assessment index system is effective for measuring the social impacts generated by redeveloped projects. © 2016 Elsevier Ltd

Chen H.,Beijing Forestry University | Chen H.,Tsinghua University | Lin L.,University of Tokyo | Li H.,Tsinghua University | And 2 more authors.
ACS Nano | Year: 2015

A stable, water-soluble fluorescent Zn/Cu nanocluster (NC) capped with a model protein, bovine serum albumin (BSA), was synthesized and applied to the reaction of hydrogen peroxide and sodium hydrogen carbonate. A significantly amplified chemiluminescence (CL) from the accelerated decomposition of peroxymonocarbonate (HCO4 -) by the nanosluster was observed. The CL reaction led to a structure change of BSA and aggregation of Zn/Cu NCs. In the presence of H2O2, Zn/Cu-S bonding between BSA scaffolds and the encapsulated Zn/Cu@BSA NC was oxidized to form a disulfide product. Zn/Cu@BSA NCs were prone to aggregate to form larger nanoparticles without the protection of scaffolds. It is revealed that the strong CL emission was initiated from the catalysis of Zn/Cu@BSA NC and the surface plasmon coupling of the formed Zn/Cu nanoparticles in a single chemical reaction. This amplified CL was successfully exploited for selective sensing of hydrogen peroxide in environmental samples. © 2015 American Chemical Society.

Zhao X.,Tsinghua University | Li H.,Beijing University of Civil Engineering and Architecture | Wu L.,Beijing Forestry University | Qi Y.,Tsinghua University
Energy Policy | Year: 2014

Local governments have replaced the national ministries that are in charge of various industries to become the primary implementer of energy-saving policies in China since 2000. This paper employs a case study-based approach to demonstrate the significance of local governments' policy measures in assisting industrial enterprises with energy-saving activities in China. Based on the longitudinal case of the Jasmine Thermal Electric Power Company, this paper hypothesizes that sub-national governments have played a major role in implementing energy-saving policies in China since the 11th Five-year-plan period. A wide range of provincial and municipal agencies collaborated in implementing five types of policy measures - informational policy, skill building, improved enforcement of central directives, price adjustment, and funding - that reduced barriers to energy saving and motivated active pursuit of energy-saving activities at industrial enterprises. The case study demonstrates how an enterprise and local governments work together to achieve the enterprise's energy-saving target. The authors will investigate the hypothesis of this paper in the context of multiple case studies that they plan to undertake in the future. © 2013 Elsevier Ltd.

Xu B.,Tsinghua University | Sun G.,Beijing Forestry University | Yu R.,Tsinghua University | Yang Z.,Tsinghua University
IEEE Transactions on Parallel and Distributed Systems | Year: 2013

Localization is of great importance in mobile and wireless network applications. Time Difference of Arrival (TDOA) is one of the widely used localization schemes, in which the target (source) emits a signal and a number of anchors (receivers) record the arriving time of the source signal. By calculating the time difference of different receivers, the location of the target is estimated. In such a scheme, receivers must be precisely time synchronized. But time synchronization adds computational cost, and brings errors which may lower localization accuracy. Previous studies have shown that existing time synchronization approaches using low-cost devices are insufficiently accurate, or even infeasible under high requirement for accuracy. In our scheme (called Whistle), several asynchronous receivers record a target signal and a successive signal that is generated artificially. By two-signal sensing and sample counting techniques, time synchronization requirement can be removed, while high time resolution can be achieved. This design fundamentally changes TDOA in the sense of releasing the synchronization requirement and avoiding many sources of errors caused by time synchronization. We implement Whistle on commercial off-the-shelf (COTS) cell phones with acoustic signal and perform simulations with UWB signal. Especially we use Whistle to localize nodes of large-scale wireless networks, and also achieve desirable results. The extensive real-world experiments and simulations show that Whistle can be widely used with good accuracy. © 1990-2012 IEEE.

Gao D.,Beijing Forestry University | Wang S.,Tsinghua University | Zhang H.,Beijing Forestry University
Journal of Intelligent and Robotic Systems: Theory and Applications | Year: 2014

This paper presents the design of neural adaptive flight control systems for the longitudinal dynamics of hypersonic vehicle. By considering the coupling between thrust and pitch moment, the proposed control strategy is derived from the solutions of a series of fast dynamical equations, which are designed based on the backstepping control and singularly perturbed system approach. The RBF neural networks are employed to approximate the unknown hypersonic dynamics. Simulation results are included to show the effectiveness of the neural adaptive control method. © Springer Science+Business Media Dordrecht 2013.

Xu B.,Northwestern Polytechnical University | Wang S.,Yantai Naval Aeronautical and Astronautical University | Wang S.,Tsinghua University | Gao D.,Beijing Forestry University | And 2 more authors.
Journal of Intelligent and Robotic Systems: Theory and Applications | Year: 2014

The command filter based robust nonlinear controller is designed for the longitudinal dynamics of a generic hypersonic aircraft in presence of parametric model uncertainty and magnitude constraints on the states and actuators. The functional subsystems are transformed into the linearly parameterized form and the controller is proposed based on dynamic inversion and adaptive gain. Since the dynamics are with cascade structure, the states are considered as virtual control and the signal is filtered to produce the limited command signal and its derivative. To eliminate the effect of the constraint, the auxiliary error compensation design is employed and the parameter projection estimation is proposed based on the compensated tracking error. The uniformly ultimately boundedness is guaranteed for the closedloop control system. Simulation results show that the proposed approach achieves good tracking performance. © Springer Science+Business Media Dordrecht 2013.

Zhu H.,Beijing Forestry University | Zhang L.,Beijing Forestry University | Wen X.,Tsinghua University | Huang X.,Tsinghua University
Bioresource Technology | Year: 2012

The feasibility of applying forward osmosis (FO) to the simultaneous thickening, digestion, and dewatering of waste activated sludge was investigated. After 19. days of operation, the total reduction efficiencies of the simultaneous sludge thickening and digestion system in terms of mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) were approximately 63.7% and 80%, respectively, and the MLVSS/MLSS ratio continuously decreased from 80.8% to 67.2%. The MLSS concentration reached 39. g/L from an initial amount of 7. g/L, indicating a good thickening efficiency. In using FO for sludge dewatering, two major factors were verified, namely, initial sludge depth and draw solution (DS) concentration. A sludge depth of 3. mm, where a dry sludge content of approximately 35% can be achieved in approximately 60. min, is recommended for future applications. In addition, the present study proved the feasibility of using seawater reverse osmosis concentrate as the DS. © 2011 Elsevier Ltd.

Zhang S.,Beijing Forestry University | Zhang P.,Beijing Forestry University | Zhang G.,Harbin Institute of Technology | Zhang G.,Tsinghua University | And 2 more authors.
Bioresource Technology | Year: 2012

To improve anaerobic sludge digestion efficiency, the effects of high-pressure homogenization (HPH) conditions on the anaerobic sludge digestion were investigated. The VS and TCOD were significantly removed with the anaerobic digestion, and the VS removal and TCOD removal increased with increasing the homogenization pressure and homogenization cycle number; correspondingly, the accumulative biogas production also increased with increasing the homogenization pressure and homogenization cycle number. The optimal homogenization pressure was 50. MPa for one homogenization cycle and 40. MPa for two homogenization cycles. The SCOD of the sludge supernatant significantly increased with increasing the homogenization pressure and homogenization cycle number due to the sludge disintegration. The relationship between the biogas production and the sludge disintegration showed that the accumulative biogas and methane production were mainly enhanced by the sludge disintegration, which accelerated the anaerobic digestion process and improved the methane content in the biogas. © 2012 Elsevier Ltd.

Yang J.,Tsinghua University | Yang J.,Beijing Forestry University | Shi F.-K.,Tsinghua University | Gong C.,Tsinghua University | Xie X.-M.,Tsinghua University
Journal of Colloid and Interface Science | Year: 2012

A series of physically cross-linked hydrogels composed poly(acrylic acid) and octylphenol polyoxyethylene acrylate with high mechanical strength are reported here with dual cross-linked networks that formed by silica nanoparticles (SNs) and hydrophobic association micro-domains (HAMDs). Acrylic acid (AA) and octylphenol polyoxyethylene acrylate with 10 ethoxyl units (OP-10-AC) as basic monomers . in situ graft from the SNs surface to build poly(acrylic acid) hydrophilic backbone chains with randomly distributed OP-10-AC hydrophobic side chains. The entanglements among grafted backbone polymer chains and hydrophobic branch architecture lead to the SNs and HAMDs play the role of physical cross-links for the hydrogels network structure. The rheological behavior and polymer concentration for gelation process are measured to examine the critical gelation conditions. The correlation of the polymer dual cross-linked networks with hydrogels swelling behavior, gel-to-sol phase transition, and mechanical strength are addressed, and the results imply that the unique dual cross-linking networks contribute the hydrogels distinctive swelling behavior and excellent tensile strength. The effects of SNs content, molecular weight of polymer backbone, and temperature on hydrogels properties are studied, and the results indicate that the physical hydrogel network integrity is depended on the SNs and HAMDs concentration. © 2012 Elsevier Inc.

Lu J.,Chiba University | Ren D.-F.,Beijing Forestry University | Wang J.-Z.,Beijing Forestry University | Sanada H.,Chiba University | Egashira Y.,Chiba University
British Journal of Nutrition | Year: 2010

Increasing attention has been paid to Spirulina for its potential clinical uses. The present study investigated the protection by dietary Spirulina platensis against d-galactosamine (d-GalN)-and acetaminophen (APAP)-induced hepatitis in ICR mice. Mice in each group (n 6) were fed with a standard diet (American Institute of Nutrition (AIN)-93G), a positive control diet containing 05% butylated hydroxytoluene (BHT), or a diet containing 3, 6 or 9% S. platensis for 1 week. On the last day the mice were treated with d-GalN (300mg/kg body weight, intraperitoneally) or APAP (150mg/kg body weight, intraperitoneally) and 24h later the mice were killed. The doses of both 6 and 9% S. platensis were found to significantly alleviate the increase of serum glutamate oxaloacetoacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) activities in d-GalN-or APAP-intoxicated mice. The observation was very similar to that of the positive control groups. Two more experiments were carried out to investigate the involvement of thiobarbituric acid-reactive substances (TBARS) and IL-18 in the suppression of 6% S. platensis on d-GalN-and APAP-induced hepatitis. The significant increase of GOT and GPT activities was found to be accompanied with the elevation of hepatic TBARS level, IL-18 mRNA expression and serum IL-18 concentration, and was significantly alleviated by supplementation with 6% S. platensis in diets. These results showed that dietary S. platensis could provide a significant protection against d-GalN-and APAP-induced liver injuries, and IL-18 and lipid peroxidation might be involved in the protective influence of S. platensis. Copyright © The Authors 2010.

Tang Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Tang Q.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Tian F.,Tsinghua University | Zhang Z.,Beijing Forestry University | And 2 more authors.
Hydrology and Earth System Sciences | Year: 2013

The zero-flow phenomenon appeared frequently in the lower reaches of the Yellow River in China in the 1990s, whereas it has almost disappeared in recent years. The disappearance of the zero-flow phenomenon should be mainly attributed to the recent water management practices. However, little is known about the effects of recent climatic variations on natural runoff. In this study, we investigated the impacts of climatic variations on natural runoff above the Huayuankou station. The results indicate that there was little increase in precipitation, but substantial recovery of natural runoff in the recent period (2003-2011) compared with the low-flow period (1991-2002). The recent precipitation was slightly greater (~2% of the baseline precipitation in 1960-1990) than precipitation in the low-flow period. However, the recent natural runoff was much larger (~14% baseline runoff) than runoff in the low-flow period. The runoff reduction in the low-flow period was mainly caused by precipitation decrease. In the recent period, precipitation accounted for a runoff reduction (~21% baseline runoff), whereas net radiation, wind speed, air temperature, and relative humidity accounted for a runoff increase (~7.5% baseline runoff). The spatial pattern of the climatic variation is a factor influencing the response of runoff to climatic variations. The reduction in runoff induced by precipitation change was offset up to half by the impacts of changes in net radiation and wind speed at most sub-basins in the recent period. © Author(s) 2013.

Zhang K.,Beijing Forestry University | Ma L.,Tsinghua University | Xu X.,Beijing Forestry University | Luo J.,Tsinghua University | Guo D.,Tsinghua University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

The surface temperature can significantly affect the flow field of drying droplets. Most previous studies assumed a monotonic temperature variation along the droplet surface. However, the present analyses indicate that a nonmonotonic spatial distribution of the surface temperature should occur. Three different patterns of the surface temperature distribution may appear during the evaporation process of liquid droplets: (i) the surface temperature increases monotonically from the center to the edge of the droplet; (ii) the surface temperature exhibits a nonmonotonic spatial distribution along the droplet surface; (iii) the surface temperature decreases monotonically from the center to the edge of the droplet. These surface temperature distributions can be explained by combining the evaporative cooling at the droplet surface and the heat conduction across the substrate and the liquid. Furthermore, a "phase diagram" for the distribution of the surface temperature is introduced and the effect of the spatial temperature distribution along the droplet surface on the flow structure of the droplet is discussed. The results may provide a better understanding of the Marangoni effect of drying droplets and provide a potential way to control evaporation-driven deposition as well as the assembly of colloids and other materials. © 2014 American Physical Society.

Gao D.-X.,Beijing Forestry University | Sun Z.-Q.,Tsinghua University | Liu J.-H.,Beijing Forestry University
Asian Journal of Control | Year: 2012

A dynamic inversion control method is proposed for a class of pure-feedback nonlinear systems. By combing the back-steeping control method with the singular perturbation theory, the virtual and the final actual control inputs are derived from the solutions of a series of fast dynamical equations. Stability analysis shows that the system output tracks the desired trajectory with bounded errors, which can be made arbitrarily small by choosing appropriate design parameters. Tracking performance is illustrated by simulation results. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society.

Xu B.,Tsinghua University | Xu B.,ETH Zurich | Gao D.X.,Beijing Forestry University | Wang S.X.,Tsinghua University
Science China Information Sciences | Year: 2011

This paper describes the design of adaptive neural controller for the longitudinal dynamics of a generic hypersonic flight vehicle (HFV) which are decomposed into two functional systems, namely the altitude subsystem and the velocity subsystem. For each subsystem, one adaptive neural controller is investigated based on the normal output-feedback formulation. For the altitude subsystem, the high gain observer (HGO) is taken to estimate the unknown newly defined states. Only one neural network (NN) is employed to approximate the lumped uncertain system nonlinearity during the controller design which is considerably simpler than the ones based on back-stepping scheme with the strict-feedback form. The Lyapunov stability of the NN weights and filtered tracking error are guaranteed in the semiglobal sense. Numerical simulation study of step response demonstrates the effectiveness of the proposed strategy in spite of system uncertainty. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.

Li M.,Beijing Forestry University | Whelan M.J.,Cranfield University | Wang G.Q.,Tsinghua University | White S.M.,Cranfield University
Biogeosciences | Year: 2013

The adsorption isotherm and the mechanism of the buffering effect are important controls on phosphorus (P) behaviors in estuaries and are important for estimating phosphate concentrations in aquatic environments. In this paper, we derive phosphate adsorption isotherms in order to investigate sediment adsorption and buffering capacity for phosphorus discharged from sewage outfalls in the Yangtze Estuary and Hangzhou Bay near Shanghai, China. Experiments were also carried out at different temperatures in order to explore the buffering effects for phosphate. The results show that P sorption in sediments with low fine particle fractions was best described using exponential equations. Some P interactions between water and sediment may be caused by the precipitation of CaHPO4 from Ca2+ and HPO2- 4 when the phosphate concentration in the liquid phase is high. Results from the buffering experiments suggest that the Zero Equilibrium Phosphate Concentrations (EPC 0) vary from 0.014 mg L-1 to 0.061 mg L-1, which are consistent with measured phosphate concentrations in water samples collected at the same time as sediment sampling. Values of EPC0 and linear sorption coefficients (K) in sediments with high fine particle and organic matter contents are relatively high, which implies that they have high buffering capacity. Both EPC0 and K increase with increasing temperature, indicating a higher P buffering capacity at high temperatures. © Author(s) 2013.

Zhu H.,Tsinghua University | Zhu H.,Beijing Forestry University | Wen X.,Tsinghua University | Huang X.,Tsinghua University
Desalination | Year: 2012

Membrane filtration is one of the most promising technologies used for the advanced treatment of secondary effluents. Despite the number of fouling-control studies that have been conducted, membrane fouling remains a problem of utmost importance. In this study, pilot-scale ceramic microfiltration equipment was used to treat real secondary effluents from a wastewater treatment plant. Reversible fouling and irreversible fouling, which are defined based on backwashing, were characterized, and the effects of coagulation and membrane pore sizes on fouling evolution, as well as the composition of foulants, were also studied. The results showed that coagulation is an effective pretreatment for the control of microfiltration fouling, and that 5. mg aluminum per liter feed water is a cost-effective dosage for treatment. In terms of stable operating time and recovered water volume, the performance of the 0.1μm ceramic membrane was the best. Results of pure water filtration experiments revealed that sodium hypochlorite solution washing recovered more flux than citric acid solution. The concept of a "trans-membrane pressure (TMP for short) turning point" was suggested as an operational signal for conducting membrane off-line chemical washing. After this point, both reversible and irreversible fouling increased drastically to maximum levels within a short span of time, resulting in difficulties in thoroughly cleaning the membrane. © 2011 Elsevier B.V..

Gao D.,Beijing Forestry University | Sun Z.,Tsinghua University | Xu B.,Northwestern Polytechnical University
International Journal of Control, Automation and Systems | Year: 2013

A fuzzy adaptive control method is proposed for a class of completely non-affine purefeedback nonlinear systems. By the combination of back-stepping control method and time scale separation, the virtual/actual control inputs are derived from the solutions of a series of fast dynamical equations. This strategy avoids the drawback of "explosion of complexity" inherently existing in the conventional back-stepping design for the pure-feedback system as the dynamic surface control (DSC) method does for the strict-feedback nonlinear system. By using mean value theorem, error system dynamic is obtained for each subsystem. Thus, Lyapunov theory can be employed for the stability analysis. It shows that the developed fuzzy adaptive control scheme achieves semi-global uniform ultimate boundedness of all the signals in the closed loop. Simulation results are presented to show the effectiveness of the approach. © 2013 Institute of Control, Robotics and Systems and The Korean Institute of Electrical Engineers and Springer-Verlag Berlin Heidelberg.

Tong X.,Beijing Forestry University | Li J.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Yu Q.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Yu Q.,University of Technology, Sydney | Lin Z.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
PLoS ONE | Year: 2014

To investigate the impacts of biophysical factors on light response of net ecosystem exchange (NEE), CO2 flux was measured using the eddy covariance technique in a winter wheat field in the North China Plain from 2003 to 2006. A rectangular hyperbolic function was used to describe NEE light response. Maximum photosynthetic capacity (Pmax) was 46.6±4.0 μmol CO2 m-2 s-1 and initial light use efficiency (α) 0.059±0.006 μmol μmol-1 in April-May, two or three times as high as those in March. Stepwise multiple linear regressions showed that Pmax increased with the increase in leaf area index (LAI), canopy conductance (gc) and air temperature (Ta) but declined with increasing vapor pressure deficit (VPD) (P<0.001). The factors influencing Pmax were sorted as LAI, g c, Ta and VPD. α was proportional to ln(LAI), g c, Ta and VPD (P<0.001). The effects of LAI, g c and Ta on α were larger than that of VPD. When Ta>25°C or VPD>1.1-1.3 kPa, NEE residual increased with the increase in Ta and VPD (P<0.001), indicating that temperature and water stress occurred. When gc was more than 14 mm s-1 in March and May and 26 mm s-1 in April, the NEE residuals decline disappeared, or even turned into an increase in gc(P<0.01), implying shifts from stomatal limitation to non-stomatal limitation on NEE. Although the differences between sunny and cloudy sky conditions were unremarkable for light response parameters, simulated net CO2 uptake under the same radiation intensity averaged 18% higher in cloudy days than in sunny days during the year 2003-2006. It is necessary to include these effects in relevant carbon cycle models to improve our estimation of carbon balance at regional and global scales. © 2014 Tong et al.

Zhang J.,Tsinghua University | Ma Y.,Tsinghua University | Ma Y.,Beijing Forestry University | Yu H.,Tsinghua University
International Journal of Systematic and Evolutionary Microbiology | Year: 2012

An actinobacterial strain, designated D48T, was isolated from the rhizosphere soil of a cypress tree collected from Mianyang in Sichuan province, China. The strain was Gram-stain-positive, catalase-positive, oxidase-negative and non-motile, with lysine as the peptidoglycan diagnostic diamino acid and acetyl as the peptidoglycan acyl type. The predominant menaquinone was MK-9(H2); small amounts of MK-7(H2), MK-10(H2) and MK-6 were also present. The major fatty acids were anteiso-C15: 0, anteiso-C17: 0 and iso-C16: 0. The isolate underwent a rod-coccus morphological cycle, had a high DNA G+C content, was aerobic and grew between 12 and 37 °C (optimum, 28 °C). On the basis of the phenotypic and chemotaxonomic analyses, 16S rRNA gene sequence comparisons and DNA-DNA hybridization data, the isolate represents a novel species of the genus Arthrobacter, for which the name Arthrobacter cupressi sp. nov. is proposed. The type strain is D48T (=DSM 24664T=CGMCC 1.10783T). © 2012 IUMS.

Hong Y.,Beijing Forestry University | Hong Y.,Tsinghua University | Sakoda A.,University of Tokyo | Sagehashi M.,University of Tokyo
Allelopathy Journal | Year: 2010

We isolated and characterised the allelochemicals from Arundo donax L. (giant reed), these were very inhibitory to toxic and bloom-forming cyanobacterium Microcystis aeruginosa. The methanol extract of dry biomass of giant reed shoot quickly inhibited the algal growth. Through solvent extraction, the methanol extract was fractioned into neutral and acidic fractions, both these fractions also inhibited the growth of M. aeruginosa, but the neutral fraction was more inhibitoy than acidic fraction. The neutral fraction was analyzed by gas chromatography/mass spectrometry (GC/MS) and was found to contain several potential allelochemicals, including indoles, ketones, esters, alcohols, etc. Among them, 3-(dimethylaminomethyl)indole (i.e. gramine, an alkaloid) was found in the neutral fraction. Gramine inhibited the M. aeruginosa at 0.47 mg-L-1 medium effective concentration (EC50 3d,)) and proved one of the strongest antialgal allelochemicals from aquatic plants.

Xu L.,Beijing Forestry University | Xu L.,Rutgers University | Han L.,Beijing Forestry University | Huang B.,Rutgers University
Journal of the American Society for Horticultural Science | Year: 2011

The objectives of this study were to examine antioxidant enzyme responses to drought stress and rewatering at both enzymatic activity and transcript levels and to determine the major antioxidant processes associated with drought tolerance and post-drought recovery for a perennial grass species, kentucky bluegrass (Poa pratensis). Antioxidant enzyme responses to drought and rewatering in a drought-tolerant cultivar (Midnight) and a drought-sensitive cultivar (Brilliant) were compared in a growth chamber. Plants were exposed to 22 days of drought stress for 'Midnight' and 18 days for 'Brilliant' before rewatering to allow the leaf relative water content (RWC) of both cultivars to drop to the same level. 'Midnight' exhibited higher photochemical efficiency (F v/F m) and lower electrolyte leakage compared with 'Brilliant' when at the same water deficit status (26% to 28% RWC). After 6 days of rewatering, all physiological parameters returned to the control level for 'Midnight', but only F v/F m fully recovered for 'Brilliant'. The transcript level of cytosolic copper/zinc superoxide dismutase (cyt Cu/Zn SOD) and ascorbate peroxidase (APX) was significantly higher in 'Midnight' than in 'Brilliant' when exposed to the same level of water deficit (26% to 28% RWC), suggesting that SOD and APX could be involved in scavenging oxidative stress-induced reactive oxygen species in kentucky bluegrass through changes in the level of gene expression. Significantly higher activities of APX, monodehydroascorbate reductase, glutathione reductase, and dehydroascorbate reductase as well as lower lipid peroxidation levels were observed in 'Midnight' versus 'Brilliant' when exposed to drought. However, the activities of SOD, catalase (CAT), and guaiacol peroxidase (POD) did not differ between the two cultivars. After 6 days of rewatering, 'Midnight' displayed significantly higher activity levels of CAT, POD, and APX compared with 'Brilliant'. The enzyme activity results indicate that enzymes involved in the ascorbate-glutathine cycle may play important roles in antioxidant protection to drought damage, whereas CAT, POD, and APX could be associated with better post-drought recovery in kentucky bluegrass.

Sun Y.,Beijing Forestry University | Qiao G.,Harbin Institute of Technology | Sun G.,Beijing Forestry University
Optics Express | Year: 2014

A compact waveguide incorporating a high-index nano-ridge sandwiched between graphene sheets is proposed for the direct generation of graphene plasmonic polaritons (GSPs) via four wave mixing (FWM). The proposed waveguide supports GSP modes at the THz frequencies and photonic modes at the infrared wavelengths. Due to the strong confinement of coupled graphene sheets, the GSP modes concentrate in the high-index nano-ridge far below the diffraction limit, which improves integral overlap with the photonic modes and greatly facilitates the FWM process. To cope with the ultra-high effective refractive of the GSP modes, an alternative energy conservation diagram is selected for the degenerated FWM, which corresponds to one pump photon transfers its energy to two signal photons and one GSP photon. The single mode condition of the generated symmetric GSP modes is analyzed by the effective index method to suppress the undesired conversion. Due to the unique tunability of GSPs, the phase matching condition can be satisfied by tuning the chemical potential of the graphene sheets employing external gates. The FWM pumped at 1,550 nm with a peak power of 1 kW is theoretically investigated by solving the modified coupled mode equations. The generated GSP power reaches its maximum up to 67 W at a propagation distance of only 43.7 μm. The proposed waveguide have a great potential for integrated chip-scale GSP source. ©2014 Optical Society of America

Yang Z.,Nanjing Agricultural University | Yu J.,Beijing Forestry University | Merewitz E.,Rutgers University | Huang B.,Rutgers University
Journal of the American Society for Horticultural Science | Year: 2012

Abscisic acid (ABA) and glycine betaine (GB) may regulate plant responses to drought or salinity stress. The objectives of this controlled-environment study were to determine whether foliar application of ABA or GB improves turf quality under drought or salinity and whether improved stress responses were associated changes in antioxidant metabolism in two C3 turfgrass species, creeping bentgrass (Agrostis stolonifera) and kentucky bluegrass (Poa pratensis). Physiological parameters evaluated included turf quality, leaf relative water content, membrane electrolyte leakage (EL), membrane lipid peroxidation [expressed as malondialdehyde (MDA) content], and activity of superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX). Abscisic acid and GB were both effective in mitigating physiological damage resulting from drought or salinity for both grass species, but effects were more pronounced on kentucky bluegrass. The most notable effects of ABA or GB application were the suppression of EL and MDA accumulation and an increase in APX, POD, and SOD activities after prolonged periods of drought (21 days) or salinity stress (35 days). These results suggest foliar application of ABA or GB may alleviate physiological damage by drought or salinity stress in turfgrass and the maintenance of membrane stability and active antioxidant metabolism could contribute to the positive effects in the stress mitigation effects.

Wang J.,Beijing Forestry University | Wang J.,Pennsylvania State University | Chen B.,Beijing Forestry University | Wang Y.,Pennsylvania State University | And 6 more authors.
Nucleic Acids Research | Year: 2013

The capacity of an organism to respond to its environment is facilitated by the environmentally induced alteration of gene and protein expression, i.e. expression plasticity. The reconstruction of gene regulatory networks based on expression plasticity can gain not only new insights into the causality of transcriptional and cellular processes but also the complex regulatory mechanisms that underlie biological function and adaptation. We describe an approach for network inference by integrating expression plasticity into Shannon's mutual information. Beyond Pearson correlation, mutual information can capture non-linear dependencies and topology sparseness. The approach measures the network of dependencies of genes expressed in different environments, allowing the environment-induced plasticity of gene dependencies to be tested in unprecedented details. The approach is also able to characterize the extent to which the same genes trigger different amounts of expression in response to environmental changes. We demonstrated the usefulness of this approach through analysing gene expression data from a rabbit vein graft study that includes two distinct blood flow environments. The proposed approach provides a powerful tool for the modelling and analysis of dynamic regulatory networks using gene expression data from distinct environments. © 2013 The Author(s).

Qi F.,Hong Kong Polytechnic University | Qi F.,Beijing Forestry University | Chu W.,Hong Kong Polytechnic University | Xu B.,Chinese Research Academy of Environmental Sciences
Applied Catalysis B: Environmental | Year: 2013

In this study, the performance of caffeine degradation and mineralization in aqueous phase by a catalyst that was prepared by incorporating cobalt into the structure of MCM41 (i.e. Co-MCM41) in activating peroxymonosulfate (PMS) was explored. Experimental results showed that Co-MCM41 activated PMS not only degraded caffeine, but also mineralized the corresponding intermediates successfully. The surface and structure properties of Co-MCM41 were characterized by several analytical methods. The leaching of cobalt ions in this process was very low, and the heterogeneous reaction dominated the caffeine decay rather than the homogeneous one, which made the reuse of catalyst highly feasible. According to the result of using quenchers, both OH and SO4 - were found in this process and the latter was the major oxidant species. Furthermore, nine major intermediates generated in this process were identified and the degradation pathway was proposed. © 2013 Elsevier B.V.

Yu H.-L.,Beijing Forestry University | Tang Y.,Beijing Forestry University | Tang Y.,GuangXi Key Laboratory of Chemistry and Engineering of Forest Products | Xing Y.,Beijing Forestry University | And 3 more authors.
Bioresource Technology | Year: 2013

A potential commercial pretreatment for furfural residues (FRs) was investigated by using a combination of green liquor and hydrogen peroxide (GL-H2O2). The results showed that 56.2% of lignin removal was achieved when the sample was treated with 0.6g H2O2/g-DS (dry substrate) and 6mL GL/g-DS at 80°C for 3h. After 96h hydrolysis with 18FPU/g-cellulose for cellulase, 27CBU/g-cellulose for β-glucosidase, the glucose yield increased from 71.2% to 83.6%. Ethylenediaminetetraacetic acid was used to reduce the degradation of H2O2, the glucose yield increased to 90.4% after the addition of 1% (w/w). The untreated FRs could bind more easily to cellulase than pretreated FRs could. The structural changes on the surface of sample were characterized by X-ray photoelectron spectroscopy. The results indicated that the surface lignin could be effectively removed during pretreatment, thereby decreasing the enzyme-lignin binding activity. Moreover, the carbonyl from lignin plays an important role in cellulase binding. © 2013 Elsevier Ltd.

Xu L.,Rutgers University | Xu L.,Beijing Forestry University | Han L.,Beijing Forestry University | Huang B.,Rutgers University
Crop Science | Year: 2011

Changes in fatty acid composition and saturation levels may be involved in leaf tolerance to dehydration during drought stress and recovery on rewatering. The objective of this study was to compare changes in compositional and saturation levels of leaf fatty acids between two cultivars of Kentucky bluegrass (Poa pratensis L.) contrasting in drought tolerance in response to drought stress and rewatering. Drought-tolerant 'Midnight' and sensitive 'Brilliant' were maintained well-watered (control) or subjected to drought for 15 d by withholding irrigation and then rewatered in a growth chamber. Compared to Brilliant, Midnight maintained higher turf quality, leaf photochemical effi ciency, relative water content, and membrane stability expressed as electrolyte leakage during drought stress. Following rewatering, Midnight recovered more rapidly in each parameter than Brilliant. The degree of fatty acid unsaturation decreased in both cultivars during drought stress, and the decrease was less pronounced and occurred later in Midnight. Fatty acid unsaturation level resumed to the control level in Midnight leaves, but did not fully recover in Brilliant after rewatering. The alteration in fatty acid unsaturation level induced by drought and rewatering were mainly due to the changes in the composition of linolenic acids (18:3), linoleic acids (18:2), palmitic acids (16:0), and stearic acids (18:0). Our results suggest that leaf dehydration tolerance and postdrought recovery in Kentucky bluegrass was associated with their ability to maintain relative higher proportion and level of unsaturated fatty acids, particularly linolenic acids and linoleic acids. © Crop Science Society of America.

Chen C.,Hunan University | Zhang P.,Beijing Forestry University | Zeng G.,Hunan University | Deng J.,Hunan University | And 2 more authors.
Chemical Engineering Journal | Year: 2010

Activated sludge process to treat municipal and industrial wastewater produces huge amounts of excess sludge. Chemical condition has been employed widely to improve sludge mechanical dewatering, but the cost is high, thus it is very important to find cheap and effective conditioners. This paper studied the improvement of sludge dewaterability with coal fly ash modified by sulfuric acid (MCFA). Through orthogonal experiments with specific resistance to filtration (SRF) as the target index, acid concentration and soaking time were verified to be the important influencing parameters in coal fly ash modification. The optimal modification conditions were: acid concentration, 4 mol l-1; ratio of acid to coal fly ash, 5:1 ml g-1; soaking time, 3 h. After modification the specific surface area of coal fly ash increased from 2.810 to 3.376 m2 g-1. The dewaterability and the settleability of the conditioned sludge were investigated with vacuum filtrating dewatering tests, centrifugal dewatering tests and settling experiments. The results showed that SRF of the sludge significantly decreased with coal fly ash addition, and the MCFA showed much stronger conditioning capacity than the raw coal fly ash (RCFA). Under a MCFA dosage of 273%, the SRF of the sludge decreased from 1.86 × 1013 to 4.23 × 1011 m kg-1, and the filter cake moisture decreased from 86.90% to 56.52%. The sludge conditioning mechanisms with MCFA mainly included improving floc formation through charge neutralization and adsorption bridging and providing the water transmitting passages by skeleton builder. © 2010 Elsevier B.V. All rights reserved.

Lan W.,South China University of Technology | Liu C.-F.,South China University of Technology | Yue F.-X.,South China University of Technology | Sun R.-C.,South China University of Technology | And 2 more authors.
Carbohydrate Polymers | Year: 2011

Ultrasound-assisted dissolution of cellulose was performed in ionic liquid 1-butyl-3-methylimidazolium chloride ([C4mim]Cl). The dissolution process was monitored with polarizing microscope. The effects of parameters including ultrasonic power and irradiation time on cellulose dissolution time were investigated. The dissolution time required for complete dissolution decreased from 190 min without assistance to 60 min irradiated with 30 W ultrasound for 20 min. The regenerated cellulose samples were characterized with FT-IR, solid-state CP/MAS 13C NMR, wide-angle X-ray diffraction and thermal analysis. The results showed that most crystalline structure of cellulose was destroyed to amorphous structure, and the remained crystalline structure of cellulose was converted to cellulose II from cellulose I in native cellulose. After dissolution and regeneration in ionic liquid, the thermal stability of cellulose decreased and the pyrolysis residues increased. © 2011 Elsevier Ltd All rights reserved.

Huang B.,Rutgers University | Rachmilevitch S.,Rutgers University | Rachmilevitch S.,Desert Research Institute | Xu J.,Rutgers University | Xu J.,Beijing Forestry University
Journal of Experimental Botany | Year: 2012

Extensive past efforts have been taken toward understanding heat tolerance mechanisms of the aboveground organs. Root systems play critical roles in whole-plant adaptation to heat stress, but are less studied. This review discusses recent research results revealing some critical physiological and metabolic factors underlying root thermotolerance, with a focus on temperate perennial grass species. Comparative analysis of differential root responses to supraoptimal temperatures by a heat-adapted temperate C3 species, Agrostis scabra, which can survive high soil temperatures up to 45 °C in geothermal areas in Yellow Stone National Park, and a heat-sensitive cogeneric species, Agrostis stolonifera, suggested that efficient carbon and protein metabolism is critical for root thermotolerance. Superior root thermotolerance in a perennial grass was associated with a greater capacity to control respiratory costs through respiratory acclimation, lowering carbon investment in maintenance for protein turnover, and efficiently partitioning carbon into different metabolic pools and alternative respiration pathways. Proteomic analysis demonstrated that root thermotolerance was associated with an increased maintenance of stability and less degradation of proteins, particularly those important for metabolism and energy production. In addition, thermotolerant roots are better able to maintain growth and activity during heat stress by activating stress defence proteins such as those participating in antioxidant defence (i.e. superoxide dismutase, peroxidase, glutathione S-transferase) and chaperoning protection (i.e. heat shock protein). © 2012 The Author.

Yu H.,Beijing Forestry University | Xing Y.,Beijing Forestry University | Lei F.,GuangXi Key Laboratory of Chemistry and Engineering of Forest Products | Liu Z.,Chunlei Industrial Group Company | And 2 more authors.
Bioresource Technology | Year: 2014

Furfural residues (FRs) were pretreated with ethanol and a green liquor (GL) catalyst to produce fermentable sugar. Anthraquinone (AQ) was used as an auxiliary reagent to improve delignification and reduce cellulose decomposition. The results showed that 42.7% of lignin was removed and 96.5% of cellulose was recovered from substrates pretreated with 1.0. mL. GL/g of dry substrate and 0.4% (w/w) AQ at 140. °C for 1. h. Compared with raw material, ethanol-GL pretreatment of FRs increased the glucose yield from 69.0% to 85.9% after 96. h hydrolysis with 18. FPU/g-cellulose for cellulase, 27. CBU/g-cellulose for β-glucosidase. The Brauner-Emmett-Teller surface area was reduced during pretreatment, which did not inhibit the enzymatic hydrolysis. Owing to the reduced surface area, the unproductive binding of cellulase to lignin was decreased, thus improving the enzymatic hydrolysis. The degree of polymerization of cellulose from FRs was too low to be a key factor for improving enzymatic hydrolysis. © 2014 Elsevier Ltd.

Zeng Y.,Zhejiang Agriculture And forestry University | Hou W.,University of Florida | Song S.,Zhejiang Agriculture And forestry University | Feng S.,Beijing Forestry University | And 3 more authors.
Briefings in Bioinformatics | Year: 2014

The capacity of apomixis to generate maternal clones through seed reproduction has made it a useful characteristic for the fixation of heterosis in plant breeding. It has been observed that apomixis displays pronounced intra- and interspecific diversification, but the genetic mechanisms underlying this diversification remains elusive, obstructing the exploitation of this phenomenon in practical breeding programs. By capitalizing on molecular information in mapping populations, we describe and assess a statistical design that deploys linkage analysis to estimate and test the pattern and extent of apomictic differences at various levels from genotypes to species. The design is based on two reciprocal crosses between two individuals each chosen from a hermaphrodite or monoecious species. A multinomial distribution likelihood is constructed by combining marker information from two crosses. The EM algorithm is implemented to estimate the rate of apomixis and test its difference between two plant populations or species as the parents. The design is validated by computer simulation. A real data analysis of two reciprocal crosses between hickory (Carya cathayensis) and pecan (C. illinoensis) demonstrates the utilization and usefulness of the design in practice. The design provides a tool to address fundamental and applied questions related to the evolution and breeding of apomixis. © The Author 2012. Published by Oxford University Press.

Zhang Y.,CAS Research Center for Eco Environmental Sciences | Liu J.,CAS Research Center for Eco Environmental Sciences | Mu Y.,CAS Research Center for Eco Environmental Sciences | Pei S.,Beijing Forestry University | And 2 more authors.
Atmospheric Environment | Year: 2011

The exchange fluxes of nitrous oxide (N2O), nitrogen oxides (NOx) and ammonia (NH3) from a maize field with three different treatments were simultaneously measured using static and dynamic chambers in the North China Plain (NCP) from June 28 to October 11, 2009. The three treatments included control plot (CK, without crop, fertilization and irrigation), fertilizer N plot (NP) and wheat straw returning plus fertilizer N plot (SN). N-fertilizer application greatly stimulated the emissions of N2O, NOx and NH3, with durations of about 10 days for N2O and NO, and about 7 days for NH3. Fertilizer loss rates were 1.08% (NP plot) and 1.20% (SN plot) as N2O-N, were 1.93% (NP plot) and 0.76% (SN plot) as NO-N, and were 5.24% (NP plot) and 3.03% (SN plot) as NH3-N. In comparison with the NP plot, the significant low fertilizer loss rates as NO-N and NH3-N from the SN plot indicated that the wheat straw returning to the field could reduce NOx and NH3 emissions. The molar ratio of NO/N2O was greater than unity for most data during the pulse emission periods induced by fertilization, and thus, nitrification was the dominant process for N2O and NO emissions during these periods. Considering the significant amount (>80%) of N2O and NOx emissions occurred during the pulse emission periods, the emissions of NOx and N2O from the investigated field were mainly ascribed to nitrification process. © 2010 Elsevier Ltd.

Dong H.,Harbin Institute of Technology | Guan X.,Tongji University | Wang D.,Harbin Institute of Technology | Li C.,Harbin Institute of Technology | And 2 more authors.
Chemosphere | Year: 2011

Batch experiments were carried out to investigate the influences of H2O2/Fe(II) molar ratio, pH, sequence of pH adjustment, initial As(V) concentration, and interfering ions on As(V) removal in H2O2-Fe(II) process from synthetic acid mine drainage (AMD). The optimum H2O2/Fe(II) molar ratio was one for arsenate removal over the pH range of 4-7. Arsenate removal at pH 3 was poor even at high Fe(II) dosage due to the high solubility of Fe(III) formed in situ. With the increase of Fe(II) dosage, arsenate removal increased progressively before a plateau was reached at pH 5 as arsenate concentration varied from 0.05 to 2.0mgL-1. However, arsenate removal was negligible at Fe/As molar ratio <3 and then experienced a striking increase before a plateau was reached at pH 7 and arsenate concentration ≥1.0mgL-1. The co-occurring ions exerted no significant effect on arsenate removal at pH 5. The experimental results with synthetic AMD revealed that this method is highly selective for arsenate removal and the co-occurring ions either improved arsenate removal or slightly depressed arsenate removal at pH 5-7. The extended X-ray absorption fine structure (EXAFS) derived As-Fe length, 3.27-3.30å, indicated that arsenate was removed by forming bidentate-binuclear complexes with FeO(OH) octahydra. The economic analysis revealed that the cost of the H2O2-Fe(II) process was only 17-32% of that of conventional Fe(III) coagulation process to achieve arsenate concentration below 10μgL-1 in treated solution. The results suggested that the H2O2-Fe(II) process is an efficient, economical, selective and practical method for arsenate removal from AMD. © 2011 Elsevier Ltd.

Qu D.,Beijing Forestry University | Qiang Z.,CAS Research Center for Eco Environmental Sciences | Xiao S.,Chinese Research Academy of Environmental Sciences | Liu Q.,Beijing Forestry University | And 2 more authors.
Separation and Purification Technology | Year: 2014

A novel submerged photocatalytic membrane distillation reactor (SPMDR) was developed and microwave electrodeless lamps were applied as the source light. Reactive Black 5 was used as a model dye with an initial concentration of 400 mg/L. The effects of TiO2 dose and feed temperature on the photodegradation efficiency and permeate flux were first investigated. The highest degradation rate was observed at 2.0 g/L TiO2 and 65 C. The permeate flux decreased by 15.8% when the TiO2 dose increased from 0.5 to 6.0 g/L. The permeate flux of the SPMDR in the presence of 2.0 g/L TiO2 was higher than the pure water flux using conventional heating, which confirms the enhancement of microwave irradiation to the membrane distillation mass transfer. The SPMDR achieved a high color (100%) and TOC (80.1%) removal efficiency after 300 min reaction. The byproducts identified in the feed included aliphatic acids (formic, acetic and maleic) and inorganic ions (SO42-, NH4+ and NO3-). The SPMDR produced high quality water because dye, TiO2 and inorganic ions were completely retained in the feed side. Formic and acetic acids were detected in the permeate side with amounts of 0.08 and 0.25 mg (i.e., 1.83 and 5.29 mg/L), respectively. Scanning electron microscope (SEM) images showed that a loose TiO2 cake layer was formed on the membrane surface, which decreased the membrane porosity and contact angle to some extent. However, the module efficiency, porosity and contact angle could be largely recovered after 30 min of washing with distilled water. © 2013 Elsevier B.V. All rights reserved.

Wang Z.,Beijing Forestry University | Wang Z.,Pennsylvania State University | Wang Y.,Pennsylvania State University | Wang J.,Beijing Forestry University | And 4 more authors.
Briefings in Bioinformatics | Year: 2014

The formation of phenotypic traits, such as biomass production, tumor volume and viral abundance, undergoes a complex process in which interactions between genes and developmental stimuli take place at each level of biological organization from cells to organisms. Traditional studies emphasize the impact of genes by directly linking DNA-based markers with static phenotypic values. Functional mapping, derived to detect genes that control developmental processes using growth equations, has proven powerful for addressing questions about the roles of genes in development. By treating phenotypic formation as a cohesive system using differential equations, a different approachçsystemsmappingçdissects the systeminto interconnected elements and thenmap genes that determine a web of interactions among these elements, facilitating our understanding of the genetic machineries for phenotypic development. Here, we argue that genetic mapping can play a more important role in studying the genotype-phenotype relationship by filling the gaps in the biochemical and regulatory process from DNA to end-point phenotype.We describe a new framework, named network mapping, to study the genetic architecture of complex traits by integrating the regulatory networks that cause a high-order phenotype. Network mapping makes use of a system of differential equations to quantify the rule by which transcriptional, proteomic andmetabolomic components interact with each other to organize into a functional whole. The synthesis of functional mapping, systems mapping and network mapping provides a novel avenue to decipher a comprehensive picture of the genetic landscape of complex phenotypes that underlie economically and biomedically important traits. © The Author 2012. Published by Oxford University Press.

Zhao J.,China Academy of Building Research | Wang X.-M.,FPInnovations Forintek Division | Chang J.M.,Beijing Forestry University | Yao Y.,China Academy of Building Research | Cui Q.,China Academy of Building Research
Composites Science and Technology | Year: 2010

The sound insulation property of wood/used tire rubber composite panel (WRCP) was investigated. A four-microphone method was used to measure the sound transmission losses of three different composite panels: WRCP, commercial compound wooden floorboard and commercial wood-based particleboard. The WRCP was manufactured in the lab with commercial urea-formaldehyde (UF) and polymeric methylene diphenyl diisocyanate (PMDI) adhesives. The test results indicated that sound insulation property of WRCP is better than that of commercial compound wooden floorboard and wood-based particleboard. In addition, the acoustic insulation of WRCP is significantly affected by the amount of rubber crumbs and PMDI adhesive used in the composite. An increase in the usage of recycled tire rubber crumbs and the dosage of PMDI adhesive significantly improve the soundproof property of the WRCP. Moreover, the microstructure of WRCP was examined using a scanning electron microscope (SEM). The sound insulation effect is also dependant on the microstructure of the interface zone of wood/rubber and densification of WRCP. The continuous interfaces are formed in the presence of sufficient UF and PMDI adhesives resulted in better soundproof WRCP. © 2010 Elsevier Ltd.

Ye J.,Harbin Institute of Technology | Mu Y.,Beijing Forestry University | Cheng X.,Beijing Forestry University | Sun D.,Beijing Forestry University
Bioresource Technology | Year: 2011

Treatment of a fresh leachate with high-strength organics and calcium from municipal solid waste (MSW) incineration plant by an up-flow anaerobic sludge blanket (UASB) reactor was investigated under mesophilic conditions, emphasizing the influence of organic loading rate (OLR). When the reactor was fed with the raw leachate (COD as high as 70,390-75,480mg/L) at an OLR of 12.5kg COD/(m3d), up to ∼82.4% of COD was removed suggesting the feasibility of UASB process for treating fresh leachates from incineration plants. The ratio of volatile solids/total solids (VS/TS) of the anaerobic sludge in the UASB decreased significantly after a long-term operation due to the precipitation of calcium carbonate in the granules. Scanning electron microscopy (SEM) observation shows that Methanosaeta-like species were in abundance, accompanied by a variety of other species. The result was further confirmed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and sequencing. © 2011.

Xu Q.,Beijing Forestry University | Xu X.,Beijing Forestry University | Shi Y.,Beijing Forestry University | Xu J.,Beijing Forestry University | Huang B.,Rutgers University
PLoS ONE | Year: 2014

Heat stress is a detrimental abiotic stress limiting the growth of many plant species and is associated with various cellular and physiological damages. Expansins are a family of proteins which are known to play roles in regulating cell wall elongation and expansion, as well as other growth and developmental processes. The in vitro roles of expansins regulating plant heat tolerance are not well understood. The objectives of this study were to isolate and clone an expansin gene in a perennial grass species (Poa pratensis) and to determine whether over-expression of expansin may improve plant heat tolerance. Tobacco (Nicotiana tabacum ) was used as the model plant for gene transformation and an expansin gene PpEXP1 from Poa pratensis was cloned. Sequence analysis showed PpEXP1 belonged to α-expansins and was closely related to two expansin genes in other perennial grass species (Festuca pratensis and Agrostis stolonifera) as well as Triticum aestivum, Oryza sativa, and Brachypodium distachyon . Transgenic tobacco plants over-expressing PpEXP1 were generated through Agrobacterium -mediated transformation. Under heat stress (42°C) in growth chambers, transgenic tobacco plants over-expressing the PpEXP1 gene exhibited a less structural damage to cells, lower electrolyte leakage, lower levels of membrane lipid peroxidation, and lower content of hydrogen peroxide, as well as higher chlorophyll content, net photosynthetic rate, relative water content, activity of antioxidant enzyme, and seed germination rates, compared to the wild-type plants. These results demonstrated the positive roles of PpEXP1 in enhancing plant tolerance to heat stress and the possibility of using expansins for genetic modification of cool-season perennial grasses in the development of heat-tolerant germplasm and cultivars. © 2014 Xu et al.

Li H.,Beijing Forestry University | Xu B.,Chinese Research Academy of Environmental Sciences | Qi F.,Beijing Forestry University | Sun D.,Beijing Forestry University | Chen Z.,Harbin Institute of Technology
Applied Catalysis B: Environmental | Year: 2014

The bezafibrate (BZF) degradation and mineralization performances of a red mud (RM) catalyst doped with cobalt (i.e. Co/RM) during the ozonation reaction have been evaluated experimentally. The purposes of this study were to study the performance reaction mechanism and intermediate. In a next stage of our study also economic evaluations for a large scale application will be considered. Results of this study showed that catalytic ozonation using Co/RM not only led to the successful degradation of BZF, but also mineralized the corresponding intermediates, in ultrapure water as well as the effluent of wastewater. Detoxification was also achieved in this reaction process. The surface and structure properties of Co/RM were characterized by several analytical methods. The leaching of toxic heavy metal from the catalyst used in this process was very low, with the heterogeneous reaction dominating the decomposition of BZF, which made the reuse of the catalyst highly feasible. The enhanced generation of hydroxyl radical was critical to the success of the catalytic activity. Furthermore, 22 of the intermediates generated during this process were identified and several degradation pathways were proposed. © 2014 Elsevier B.V.

Geng Y.,Beijing Forestry University | Dighton J.,Rutgers University | Gray D.,Rutgers University
Applied Soil Ecology | Year: 2012

Disturbance is an important factor in changing ecological processes. Forested ecosystems undergo natural disturbances of fire and windthrow and disturbances involved in management (thinning, harvesting, control burning). Using the New Jersey pine barrens as model system for eastern US mixed forests, we have observed that under conditions of repeated physical soil disruption or control burning, the pine barrens forest understory can change from ericaceous to graminoid species dominance through suppression of the ericaceous plants. In order to predict changes in soil properties and assess the potential to maintain this alternate herbaceous layer community, replicate manipulation plots were established the Franklin Parker Preserve in the New Jersey pine barrens. The manipulations consisted of: intact forest controls (CONT), canopy tree thinning (THIN) and canopy tree thinning plus ercicaceous stem removal and soil tilling (THIN & PLOW). The manipulations were designed to increase sunlight penetration to the forest floor and to encourage graminoid plant species establishment. Soil active carbon, microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN), six hydrolytic enzyme activities and two oxidative enzyme activities under three different treatments were measured. In the 0-10. cm soil depth, we observed that protease and arylsulfatase activity showed a significant decrease in the THIN and THIN & PLOW treatments compared to CONT, the activities of cellulase and phenol oxidase were significantly lower in THIN than CONT and THIN & PLOW, whereas the trend of peroxidase activity was opposite. There were no significant differences between treatments for glucosaminase, glucosidase and acid phosphatase activities. For the 10-20. cm soil depth only acid phosphatase and phenol oxidase activity significantly differed between treatments. We found that all enzyme activities except for peroxidase were significantly lower in the 10-20. cm soil horizon than in the 0-10. cm; peroxidase activity was significantly higher in the lower soil horizon. We demonstrated the activities of cellulase, phenoloxidase, arylsulfatase and protease were significantly and positively related to active C, but peroxidase activity was negatively correlated. Less expected is that only phenol oxidase was related to soil MBC, whereas the correlations between peroxidase, phenol oxidase, arysulfatase, protease activities and soil MBN were obvious. By understanding the relationships between microbial activity (enzyme production) and disturbance, we can determine the beneficial effects of many management practices on the potential nutrient availability for subsequent tree growth, since these enzymes are key to nutrient mineralization and carbon dynamics in soil. © 2012 Elsevier B.V.

Zhang J.,CAS Institute of Plant Physiology and Ecology | Zhang J.,Texas AgriLife Research Center | Liu H.,CAS Institute of Plant Physiology and Ecology | Sun J.,Beijing Forestry University | And 5 more authors.
PLoS ONE | Year: 2012

Fatty acid desaturases play important role in plant responses to abiotic stresses. However, their exact function in plant resistance to salt stress is unknown. In this work, we provide the evidence that FAD2, an endoplasmic reticulum localized ω-6 desaturase, is required for salt tolerance in Arabidopsis. Using vacuolar and plasma membrane vesicles prepared from the leaves of wild-type (Col-0) and the loss-of-function Arabidopsis mutant, fad2, which lacks the functional FAD2, we examined the fatty acid composition and Na +-dependent H + movements of the isolated vesicles. We observed that, when compared to Col-0, the level of vacuolar and plasma membrane polyunsaturation was lower, and the Na +/H + exchange activity was reduced in vacuolar and plasma membrane vesicles isolated from fad2 mutant. Consistent with the reduced Na +/H + exchange activity, fad2 accumulated more Na + in the cytoplasm of root cells, and was more sensitive to salt stress during seed germination and early seedling growth, as indicated by CoroNa-Green staining, net Na + efflux and salt tolerance analyses. Our results suggest that FAD2 mediated high-level vacuolar and plasma membrane fatty acid desaturation is essential for the proper function of membrane attached Na +/H + exchangers, and thereby to maintain a low cytosolic Na + concentration for salt tolerance during seed germination and early seedling growth in Arabidopsis. © 2012 Zhang et al.

Qiao G.,Harbin Institute of Technology | Hong Y.,Harbin Institute of Technology | Sun G.,Beijing Forestry University | Yang O.,Hunan University
IEEE Sensors Journal | Year: 2013

Compared with traditional sensors powered by the grid, energy-harvesting wireless sensors have many significant advantages, especially when applied in harsh environments. A novel power supply element, i.e., concrete battery, is designed for the wireless corrosion-monitoring sensors. Then, the power generation capacity of the corrosion-sensitive materials (Mg and Zn) is verified in a series of simulated concrete pore solutions. Furthermore, the electric quantity generated during the corrosion process is analyzed in detail. The results indicate that the novel concrete batteries based on Mg or Zn materials are a promising solution for powering wireless corrosion-monitoring sensors. © 2001-2012 IEEE.

Yu J.,Beijing Forestry University | Yu J.,Rutgers University | Chen L.,Beijing Forestry University | Xu M.,Rutgers University | And 2 more authors.
Crop Science | Year: 2012

Drought and elevated temperature often occur alone or in combination in many areas, limiting cool-season grass growth. Rising atmospheric CO2 concentration may affect plant adaptation to drought and high temperature. The objective of this study was to investigate the effectiveness of elevated CO2 in mitigating the negative effects of drought or elevated temperature alone or a combination of these stresses on physiological processes in a perennial grass species. The effects of these treatments on water relations, photosynthesis, and respiration were determined in tall fescue (Festuca arundinacea Schreb. cultivar Rembrandt). Grass plants were subjected to the following treatments in growth chambers: heat stress (30°C or 5°C above the optimal level of 25°C), drought stress by maintaining soil water content at 50% of field capacity, or the combined two stresses for 28 d. Stressed and unstressed control plants were exposed to a constant level of either ambient CO2 (400 μL L-1) or elevated CO2 (800 μL L-1). At ambient CO2 concentration, drought and the combined stress for 28 d caused significant decline in leaf relative water content (RWC), photochemical efficiency (ratio of variable to maximum fluorescence [Fv:Fm]), net photosynthetic rate (A), stomatal conductance (gs), maximal ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco)-limited rate of photosynthesis (Vcmax), and maximal electron transport-limited rate of photosynthesis (Jmax) but increased membrane electrolyte leakage (EL) and dark respiration rate (Rd). Elevated temperature to 5°C above the optimal level resulted in the increases in gs, EL, and Rd but had no significant effects on the other physiological parameters. Drought stress for 28 d was more detrimental than increasing temperature by 5°C for tall fescue and the combined stress was more detrimental than either stress alone. Elevated CO2 mitigated the degree of change in all physiological factors under drought or heat stress and resulted in increases in A (162%) and RWC (19%) and a reduction in EL (21%) under the combined stress. These results suggest that elevated CO2 could improve tall fescue tolerance to drought and elevated temperature by enhancing plant water status, cellular membrane stability, and photosynthesis capacity and by suppressing gs for water loss and C consumption through lowering respiration rate. © Crop Science Society of America.

Cai M.-Q.,Beijing Forestry University | Feng L.,Beijing Forestry University | Jiang J.,Harbin Institute of Technology | Qi F.,Beijing Forestry University | Zhang L.-Q.,Beijing Forestry University
Water Research | Year: 2013

Chlorine has been documented that it can effectively remove some pharmaceuticals. Recently, new active oxidants chlorine monoxide and molecular chlorine, which exist as free active chlorine in solution, were reported during pharmaceuticals chlorination. In this study, reaction kinetics, active oxidants, and transformation products during antipyrine chlorination were investigated with batch experiments. The reaction orders in [chlorine] were determined at various pH (6.53-7.62) and ranged from 1.13 ± 0.15 to 1.59 ± 0.08, which indicated that antipyrine chlorination is the concurrent existence of reactions appearing first-order and second-order in [chlorine]. The results by varying solution conditions (solution pH, chloride, ionic strength, and buffer concentration) show that chlorine monoxide and molecular chlorine play significant roles during the process of antipyrine chlorination. With kinetics modeling, the second-order rate constants for hypochlorous acid, chlorine monoxide, and molecular chlorine were obtained at 25 ± 2 °C (units: M-1 s-1): kHOCl = 3.23 × 103, kCl2 = 2.86 × 107, kCl2O = 8.38 × 109 (R2 = 0.9801). At pH 7, hypochlorous acid and chlorine monoxide are the main contributors to the degradation of antipyrine, about 80% and 20%, respectively (calculated by kHOCl, kCl2 and kCl2O). By applying these rate constants to predict the antipyrine elimination in real water matrixes (surface water, ground water), a good agreement was obtained, particularly in ground water. Moreover, liquid chromatography-tandems mass spectrometry (LC-MS/MS) and gas chromatograph-mass spectrometry (GC-MS) were used for products identification. Two main intermediate products and three stable products were observed during the process of antipyrine chlorination. The possible routes for antipyrine chlorination were proposed, which mainly consisted of halogenations, dealkylations and hydroxylations. © 2013 Elsevier Ltd.

Wu R.,Beijing Forestry University | Cao J.,Simon Fraser University | Huang Z.,Henan Institute of Science and Technology | Wang Z.,Pennsylvania State University | And 2 more authors.
BMC Systems Biology | Year: 2011

Background: Every phenotypic trait can be viewed as a "system" in which a group of interconnected components function synergistically to yield a unified whole. Once a system's components and their interactions have been delineated according to biological principles, we can manipulate and engineer functionally relevant components to produce a desirable system phenotype.Results: We describe a conceptual framework for mapping quantitative trait loci (QTLs) that control complex traits by treating trait formation as a dynamic system. This framework, called systems mapping, incorporates a system of differential equations that quantifies how alterations of different components lead to the global change of trait development and function through genes, and provides a quantitative and testable platform for assessing the interplay between gene action and development. We applied systems mapping to analyze biomass growth data in a mapping population of soybeans and identified specific loci that are responsible for the dynamics of biomass partitioning to leaves, stem, and roots.Conclusions: We show that systems mapping implemented by design principles of biological systems is quite versatile for deciphering the genetic machineries for size-shape, structural-functional, sink-source and pleiotropic relationships underlying plant physiology and development. Systems mapping should enable geneticists to shed light on the genetic complexity of any biological system in plants and other organisms and predict its physiological and pathological states. © 2011 Wu et al; licensee BioMed Central Ltd.

Qi F.,Beijing Forestry University | Xu B.,Chinese Research Academy of Environmental Sciences | Zhao L.,Beijing Forestry University | Chen Z.,Harbin Institute of Technology | And 3 more authors.
Applied Catalysis B: Environmental | Year: 2012

The efficiency and mechanism of catalytic ozonation of 2,4,6-trichloroanisole (TCA) by metal oxide modified bauxite were studied. TCA was effectively degraded by catalytic ozonation in the presence of iron- or manganese-modified bauxite (IMB or MMB). The effect of water pH on catalytic ozonation indicated that surface property was the key factor that influenced the activity of catalyst. Analysis results of the isoelectric point (IEP) and zeta potential for catalyst further confirmed that a lower zeta potential for modified bauxite enhanced catalytic activity. Results of both catalytic ozone decomposition and radical scavengers experiments indicated that catalytic ozonation by IMB or MMB followed a hydroxyl radical (. OH) reaction pathway. The main reaction pathway was proposed that adsorption of both ozone and TCA in the micropores and subsequent interaction (direct and indirect oxidation) between them that was confirmed by the analysis of the surface pore volume and surface hydroxyl groups, being followed by the diffusion of ozone and TCA on the mesoporous surface, in which surface hydroxyl groups covering mesoporous surface initialed ozone decomposition to generate . OH, resulted in TCA degradation. © 2012 Elsevier B.V..

Cheng X.,Harbin Institute of Technology | Huang X.,Harbin Institute of Technology | Wang X.,Beijing Forestry University | Sun D.,Beijing Forestry University
Journal of Hazardous Materials | Year: 2010

The influence of calcination of Zn-Al layered double hydroxides (LDHs) on their phosphate adsorption capacity was studied in order to improve phosphorus removal from an excess sludge liquor. Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermogravimetry-differential scanning calorimetry (TG-DSC) and nitrogen adsorption-desorption were employed to characterize the raw Zn-Al and the calcined products. The results reveal that the Zn-Al LDHs evolved to a phase of mixed metal oxides with the calcination temperature increasing to 300°C and finally to spinel ZnAl2O4 at 600°C. When the Zn-Al was calcined at 300°C, the interlayer carbonate ions were removed and the greatest BET surface area of 81.20m2/g was achieved. The tested phosphate adsorption capacities of the raw and calcined Zn-Al were closely related to the evolution of physicochemical properties of the LDHs during the calcination. The Zn-Al-300 (Zn-Al LDHs calcined at 300°C) exhibited the highest P uptake of 41.26mg P/g in 24h. The phosphate adsorption by the raw Zn-Al and the Zn-Al-300 both follows a pseudo-second-order kinetic model; the adsorption isotherms show a good fit with a Langmuir-type equation. © 2009 Elsevier B.V.

Song Y.,Beijing Forestry University | Song Y.,Rutgers University | Yu J.,Nanjing Agricultural University | Huang B.,Rutgers University
PLoS ONE | Year: 2014

Elevated CO2 concentration may promote plant growth while high temperature is inhibitory for C3 plant species. The interactive effects of elevated CO2 and high temperatures on C3 perennial grass growth and carbon metabolism are not well documented. Kentucky bluegrass (Poa pratensis) plants were exposed to two CO2 levels (400 and 800 mmol mol-1) and five temperatures (15/12, 20/17, 25/22, 30/27, 35/32°C, day/night) in growth chambers. Increasing temperatures to 25°C and above inhibited leaf photosynthetic rate (Pn) and shoot and root growth, but increased leaf respiration rate (R), leading to a negative carbon balance and a decline in soluble sugar content under ambient CO2. Elevated CO2 did not cause shift of optimal temperatures in Kentucky bluegrass, but promoted Pn, shoot and root growth under all levels of temperature (15, 20, 25, 30, and 35°C) and mitigated the adverse effects of severe high temperatures (30 and 35°C). Elevated CO2-mitigation of adverse effects of high temperatures on Kentucky bluegrass growth could be associated with the maintenance of a positive carbon balance and the accumulation of soluble sugars and total nonstructural carbohydrates through stimulation of Pn and suppression of R and respiratory organic acid metabolism. © 2014 Song et al.

Jian H.-L.,Beijing Forestry University | Liao X.-X.,South China University of Technology | Zhu L.-W.,Beijing Forestry University | Zhang W.-M.,Nanjing Academy of Wild Plant | Jiang J.-X.,Beijing Forestry University
Journal of Colloid and Interface Science | Year: 2011

A biosurfactant, named tea saponin (TS), was isolated and purified from the defatted seed of Camellia oleifera Abel. The characterization of TS including molecular weight, glycosyl composition, and thermal behavior as well as the surface and foaming properties was conducted. The synergistic interactions of binary systems of CTAB-TS, SDS-TS, and Brij35-TS were investigated. The results show that TS had a weight-average molecular weight of 809.12gmol -1 and contained four aglycones of l-rhamnose, d-galactose, d-glucose, and d-glucuronic acid. The critical micelle concentration (cmc) of 2.242mmolL -1 and the minimum surface tension (γ cmc) of 43.5mNm -1 were determined for TS. Synergisms in surface tension reduction efficiency, in mixed micelle formation, and in surface tension reduction effectiveness were observed in CTAB-TS and SDS-TS systems, whereas that was not shown in Brij35-TS mixtures. The mixtures of TS with CTAB and SDS showed synergism in foaming efficiency, but this synergism did not exist in Brij35-TS system with respect to the surface properties. Nevertheless, there appears to be no significant correlation between foam stability and the surface properties. © 2011 Elsevier Inc.

Chen L.,Beijing Forestry University | Zhang Z.,Beijing Forestry University | Li Z.,Beijing Forestry University | Tang J.,The Ecosystems Center | And 2 more authors.
Journal of Hydrology | Year: 2011

Urban reforestation in China has led to increasing debate about the impact of urban trees and forests on water resources. Although transpiration is the largest water flux leaving terrestrial ecosystems, little is known regarding whole tree transpiration in urban environments. In this study, we quantified urban tree transpiration at various temporal scales and examined the biophysical control of the transpiration pattern under different water conditions to understand how trees survive in an urban environment. Concurrent with microclimate and soil moisture measurements, transpiration from C. edrus deodara(Roxb)Loud. ., Zelkova schneideriana Hend.-Mazz., Euonymus bungeanus Maxim., and Metasequoia glyptostroboides Hu et cheng was measured over a 2-year period using thermal dissipation probe (TDP) techniques. The average monthly transpiration rates reached 12.78 ± 0.73 (S.E.) mm, 1.79 ± 0.16. mm, 10.18 ± 0.55. mm and 19.28 ± 2.24. mm for C. deodara, Z.schneideriana, E. bungeanus and M. glyptostroboides, respectively. Transpiration rates from M. glyptostroboides reported here may need further study as this species showed much higher sap flows and greater transpiration fluctuation under different environmental conditions than other species. Because of deep soil moisture supply, summer dry spells did not reduce transpiration rates even when tree transpiration exceeded rainfall. While vapor pressure deficit (VPD) was the dominant environmental factor on transpiration, trees controlled canopy conductance effectively to limit transpiration in times of water stress. Our results provide evidence that urban trees could adopt strong physiological control over transpiration under high evaporative demands to avoid dehydration and can make use of water in deeper soil layers to survive summer dry spells. Moreover, urban trees have the ability to make the best use of precipitation when it is limited, and are sensitive to soil and air dryness. © 2011 Elsevier B.V.

Jian H.,Beijing Forestry University | Zhu L.,Beijing Forestry University | Zhang W.,Nanjing Academy of Wild Plant | Sun D.,Nanjing Academy of Wild Plant | Jiang J.,Beijing Forestry University
Carbohydrate Polymers | Year: 2012

Galactomannan (G) from Gleditsia sinensis Lam. and xanthan gum (X), as sustained release materials for controlled delivery of theophylline, were mixed in different ratios of 7:3, 5:5, and 3:7 to yield enhanced release-controlling performance. The polysaccharides content of tablets was 10% (w/w), either alone or in mixtures. From in vitro dissolution test, G10% and X10% matrices released 91.4 and 87.7% of drug within 24 h, respectively. The synergistic interactions between galactomannan and xanthan effectively retarded the drug diffusion, and the most sustained drug release (75.5% at 24 h) was found in formulation GX7:3. The drug release data fitted to the kinetic model indicated the anomalous transport mechanism (0.5 < n < 1.0). Additionally, the swelling behavior and morphological changes of the tablets were investigated. The results illustrated the potential of binary mixtures of G. sinensis galactomannan and xanthan as novel sustained release materials for controlled drug delivery. © 2011 Elsevier Ltd. All rights reserved.

Dang Y.,Beijing Forestry University | Ye J.,Zhejiang University of Technology | Mu Y.,Beijing Forestry University | Qiu B.,Beijing Forestry University | Sun D.,Beijing Forestry University
Applied Microbiology and Biotechnology | Year: 2013

We investigated the treatment of fresh leachate from municipal solid waste incineration plants with highstrength organics using a lab-scale expanded granular sludge bed (EGSB) reactor. The reactor was operated at a mesophilic temperature (33 °C) for 118 days. The influent chemical oxygen demand (COD) of the leachate gradually increased to over 70,000 mg/L, and the organic loading rate increased to 18 kg COD/(m3 day). An average COD removal efficiency of 86.7 % was achieved when the reactor was fed with raw leachate, which suggests the feasibility of the EGSB process for leachate treatment. The microbial communities in the sludge from the reactor during the trial operation were constructed by denaturing gradient gel electrophoresis, clone libraries, and real-time quantitative polymerase chain reaction. The dominant group for archaea was Methanosaeta, with 68.4 % proportion at the start of the operation, and then changed to Methanosarcina, with a proportion of 62.3 %, after 118 days of operation. The dominant group of eubacteria was confirmed to be Firmicutes throughout the operation process, with the proportion increasing from >50 to 81.2 %. Almost all the operational taxonomic units of Firmicutes belonged to the order Clostridiales, with characteristic spore formation. The microbial diversity of the population was low under raw leachate as feed in the reactor. The dynamics of the microbial community in the anaerobic granular sludge was discussed relating with the operating status of the EGSB reactor. © Springer-Verlag Berlin Heidelberg 2013.

Han D.,Beijing Forestry University | Han D.,Weifang University | Huang X.,Beijing Forestry University | Fu H.,Beijing Forestry University
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

To measure plant leaf area quickly and accurately, a method of plant leaf area measurement based on color channel similarity image segmentation was put forward. In this paper, plant leaf area was separated by using the color channel similarity and an auto adaptive threshold. After the pixels of the leaf area and the referenced rectangle were counted, the leaf area was calculated. Experiments showed that this method was more accurate and had a strong robustness to the shadow and piebald, and the misclassification error was only 1.23%. So this method greatly improves the accuracy of measurement and is a practical method of plant leaf area measurement by taking pictures and can be embedded in mobile devices such as smart mobile phones.

Jian H.-L.,Beijing Forestry University | Cristhian C.,Lund University | Zhang W.-M.,Nanjing Academy of Wild Plant | Jiang J.-X.,Beijing Forestry University
Food Hydrocolloids | Year: 2011

The seeds of Gleditsia sinensis Lam., widespread in China, are an important source of galactomannans. G. sinensis gum was extracted from whole seeds using baking, boiling water and acid dehulling pretreatment, respectively. The physicochemical properties of the three isolated G. sinensis gums were studied to evaluate three pretreatment methods. The results illustrated that the properties of G. sinensis gum were significantly influenced by dulling method (p < 0.05) including the yield, M/G ratio, viscosity, chemical composition and molecular weight. Power-law model (σ=k·γ̇n) was applied to the rheological measurements, which indicated that solutions of Gb, Gw and Ga gum behaved as pseudoplastic fluids at the concentration of 0.5% (w/v). The gum obtained by acid pretreatment (Ga) had the lowest yield of 20-24% (w/w). However Ga showed a pronounced shear-thinning behavior and particularly higher viscosity compared with the gums extracted by baking pretreatment (Gb) and boiling water dehulling method (Gw). The mannose to galactose ratios (M/G ratio) for Gb, Gw and Ga were found to be 4.5, 4.4 and 6.9, respectively. The highest molecular weight of 3.31 × 106 Da was observed for the galactomannans of Gb. © 2010 Elsevier Ltd.

Wang K.,Beijing Forestry University | Yang H.,Beijing Forestry University | Yao X.,International Center for Bamboo And Rattan | Xu F.,Beijing Forestry University | And 2 more authors.
Bioresource Technology | Year: 2012

In order to understand the behaviors of hemicelluloses and lignin under the given acidic conditions with increasing severity, the structural characteristics were elucidated in detail by both wet chemistry methods and spectroscopic analyses in this study. Although acidic pretreatment significantly hydrolyzed the glycosidic linkages in xylan backbone and then reduced the molecular weight of xylan from 89,600 to 19,630g/mol, a slightly increased amount of glucuronic acid was observed, probably attributing to the maintenance of ester bonds. The serious structural variation occurred in lignin macromolecule was evidenced by the extensive degradation of β-O-4 ether linkages and resinol substructure, together with the changes in the ratios of the three monolignols in ester-bond, ether-bond and non-condensed phenolic compounds. At the most severity, obvious condensation reactions introduced the clear shift of C 2 and C 5 correlations and the absence of C 6 correlation in guaiacyl units by 2D HSQC analysis. © 2012 Elsevier Ltd.

Liu S.,Beijing Forestry University | Chen W.,Beijing Forestry University | Chen W.,CAS Institute of Genetics and Developmental Biology | Qu L.,Beijing Forestry University | And 4 more authors.
Analytical and Bioanalytical Chemistry | Year: 2013

Phytohormones act at relatively low concentrations as major regulatory factors of plant growth and development, and cross talk of phytohormones is currently of great interest throughout the plant science community. To meet this demand, a method that is capable of simultaneously analyzing diverse plant hormones is essential. This paper introduces a high-performance liquid chromatographic separation technique coupled with sensitive and selective ion trap mass spectrometry to simultaneously determine 24 or more acidic and alkaline phytohormones, including auxin, cis- and trans-abscisic acid, 11 cytokinins, and 10 gibberellins, in a single injection of sample. A binary solid-phase extraction using Oasis MCX cartridges for cations and Oasis MAX cartridges for anions was used to prepurify more than 24 acidic and alkaline phytohormones from a single plant extract. The method showed good linearity for all 24 phytohormones with R 2 values ranging from 0.9903 to 0.9997. Limits of detection for most of the phytohormones were in the femtomole range with some extending into the sub-femtomole range. This method was applied to hundreds of plant samples comprising different tissues from various plants, including herbaceous, woody climbing, and woody plants to demonstrate feasibility and to validate the methodology. © 2012 Springer-Verlag Berlin Heidelberg.

Xing Y.,Beijing Forestry University | Ji L.,Beijing Forestry University | Liu Z.-P.,Chunlei Industrial Group Company | Zhang W.-M.,Nanjing Academy of Wild Plant | Jiang J.-X.,Beijing Forestry University
Industrial Crops and Products | Year: 2015

Surfactants are popular additives for the prevention of the inhibitory effect of lignin on cellulolytic enzymes. Saponin is a type of natural surfactant extracted from Gleditsia spp. In this study, the effect of saponin on the high-solids-loading enzymatic hydrolysis of furfural residues (FRs) with a lignin content of 45% was investigated. The optimal dosage of Gleditsia saponin (GS) was determined to be 25-fold greater than its critical micelle concentration (CMC; 0.16. g/L). The addition of GS increased the cellulose conversion by up to 52.63% in high-solids-loading enzymatic hydrolysis. Due to the addition of GS, a maximum cellulose conversion of 74.88% was achieved after FRs had hydrolyzed for 120. h at a solids loading of 20% (w/w) with 30 filter paper unit (FPU)/g-cellulose. The decrease in cellulose conversion was found to exhibit a linear correlation with an increase in the solids loadings from 20.0% to 27.5% (w/w). The surface structural variations of hydrolytic residues were characterized by X-ray photoelectron spectroscopy (XPS). The results indicated that the carbonyl groups of lignin facilitated the binding of GS to the surface of lignin, which resulted in a decrease in the adsorption of between the enzyme and lignin. Interestingly, GS could maintain enzymatic activity in the supernatants. © 2014 Elsevier B.V.

Wang S.,North China Electrical Power University | Zhang Z.,Beijing Forestry University | Sun G.,U.S. Department of Agriculture | Strauss P.,Federal Agency for Water Management | And 3 more authors.
Hydrology and Earth System Sciences | Year: 2012

Model calibration is essential for hydrologic modeling of large watersheds in a heterogeneous mountain environment. Little guidance is available for model calibration protocols for distributed models that aim at capturing the spatial variability of hydrologic processes. This study used the physically-based distributed hydrologic model, MIKE SHE, to contrast a lumped calibration protocol that used streamflow measured at one single watershed outlet to a multi-site calibration method which employed streamflow measurements at three stations within the large Chaohe River basin in northern China. Simulation results showed that the single-site calibrated model was able to sufficiently simulate the hydrographs for two of the three stations (Nash-Sutcliffe coefficient of 0.65-0.75, and correlation coefficient 0.81-0.87 during the testing period), but the model performed poorly for the third station (Nash-Sutcliffe coefficient only 0.44). Sensitivity analysis suggested that streamflow of upstream area of the watershed was dominated by slow groundwater, whilst streamflow of middle- and down- stream areas by relatively quick interflow. Therefore, a multi-site calibration protocol was deemed necessary. Due to the potential errors and uncertainties with respect to the representation of spatial variability, performance measures from the multi-site calibration protocol slightly decreased for two of the three stations, whereas it was improved greatly for the third station. We concluded that multi-site calibration protocol reached a compromise in term of model performance for the three stations, reasonably representing the hydrographs of all three stations with Nash-Sutcliffe coefficient ranging from 0.59-072. The multi-site calibration protocol applied in the analysis generally has advantages to the single site calibration protocol. © Author(s) 2012.

Zhang Y.,Beijing Forestry University | Wei H.,University of Arizona | Nearing M.A.,U.S. Department of Agriculture
Hydrology and Earth System Sciences | Year: 2011

This study presents unique data on the effects of antecedent soil moisture on runoff generation in a semi-arid environment, with implications for process-based modeling of runoff. The data were collected from four small watersheds measured continuously from 2002 through 2010 in an environment where evapo-transpiration approaches 100% of the infiltrated water on the hillslopes. Storm events were generally intense and of short duration, and antecedent volumetric moisture conditions were dry, with an average in the upper 5 cm soil layer over the nine year period of 8% and a standard deviation of 3%. Sensitivity analysis of the model showed an average of 0.05 mm change in runoff for each 1% change in soil moisture, indicating an approximate 0.15 mm average variation in runoff accounted for by the 3% standard deviation of measured antecedent soil moisture. This compared to a standard deviation of 4.7 mm in the runoff depths for the measured events. Thus the low variability of soil moisture in this environment accounts for a relative lack of importance of storm antecedent soil moisture for modeling the runoff. Runoff characteristics simulated with a nine year average of antecedent soil moisture were statistically identical to those simulated with measured antecedent soil moisture, indicating that long term average antecedent soil moisture could be used as a substitute for measured antecedent soil moisture for runoff modeling of these watersheds. We also found no significant correlations between measured runoff ratio and antecedent soil moisture in any of the four watersheds. © 2011 Author(s).

Zhang H.,Beijing Forestry University | Wang X.,U.S. Department of Agriculture | Su J.,Beijing Forestry University
Holzforschung | Year: 2011

The objective of this study was to investigate how a stress wave travels in a standing tree as it is introduced into the tree trunk through a mechanical impact. A series of stress wave time-of-flight (TOF) data were obtained from three freshly-cut red pine (Pinus resinosa Ait.) logs by means of a two-probe stress wave timer. Two-dimensional (2D) and three-dimensional (3D) stress wave contour maps were constructed based on the experimental data using a commercial software. These stress wave contour maps represent the wave fronts in a time sequence, illustrating the flow of stress wave energy within a log. The analysis of TOF data and wave fronts indicates that stress wave propagation in standing trees is affected by tree diameter, travel distance, and internal wood conditions (wood properties and structural defects). When a stress wave is introduced into a tree trunk from a point source, it initially propagates in the impact direction as a 3D wave. Then the flow of the stress wave energy gradually changes towards the longitudinal directions. As the diameter-to-distance ratio reaches 0.1 or below, the wave begins to travel as a quasi 1D wave. © 2011 by Walter de Gruyter · Berlin · Boston.

Rao L.Y.,Beijing Forestry University | Sun G.,U.S. Department of Agriculture | Ford C.R.,U.S. Department of Agriculture | Vose J.M.,U.S. Department of Agriculture
Transactions of the ASABE | Year: 2011

Global climate change has direct impacts on watershed hydrology through altering evapotranspiration (ET) processes at multiple scales. There are many methods to estimate forest ET with models, but the most practical and the most popular one is the potential ET (PET) based method. However, the choice of PET methods for AET estimation remains challenging. This study explored ways to identify appropriate PET models for two small forested watersheds, one dominated by conifer plantation and one dominated by native naturally regenerated deciduous hardwoods, by using long-term hydrometeorological data collected at the Coweeta Hydrologic Laboratory in the humid Appalachians in the southeastern U.S. Our specific objectives were to: (1) contrast three common PET models (FAO-56 grass reference ET, Hamon PET, and Priestley-Taylor PET) and compare these PET estimates with measured AET at monthly and annual temporal scales, and (2) derive correction factors for the FAO-56 grass reference ET and Hamon PET models at the monthly scale using the Priestley-Taylor equation as the standard method for estimating forest PET. We found that different PET models gave significantly different PET estimates. The Priestley-Taylor equation gave the most reasonable estimates of forest PET for both watersheds. We conclude that the uncorrected Hamon and FAO PET methods would cause large underestimates of forest PET. Annual PET rates of the conifer watershed were higher than those of the native deciduous watershed due to the lower albedo (thus higher net radiation) in the former compared to the latter. Monthly correction factors provided useful tools for forest PET estimation in those areas lacking climatic data (i.e., radiation, humidity, and wind speed). © 2011 American Society of Agricultural and Biological Engineers.

Tan H.-Y.,Beijing Forestry University | Li J.-Y.,Shandong Institute of Business and Technology
Procedia Engineering | Year: 2011

This paper indicates that Extenics theory can be used to solve the problem of mine safety. The method includes 4 steps: building the evaluation indexes system and matter-element model, determining the classical field and controlled field of the matter-element model of the coal mine safety comprehensive evaluation, determining the connection function of each index on every safety level and determining the evaluation grade. This paper builds up a coal mine safety comprehensive evaluation indexes system and a matter-element model of coal mine based on extension theory, and then illustrates.the model using a case of Bei-zao Mine and its data. © 2011 Published by Elsevier Ltd.

Zhao C.-L.,Beijing Forestry University | Cui B.-K.,Beijing Forestry University | Steffen K.T.,University of Helsinki
Nordic Journal of Botany | Year: 2013

Yuchengia gen. nov. is proposed to accommodate Perenniporia narymica. It represents a monophyletic lineage within the core polyporoid clade based on sequences of the rDNA ITS and nLSU regions, and it is distinct from Perenniporia s.s. Yuchengia shares some characters with Perenniporia, both having thick-walled and cyanophilous basidiospores, but differs by having acyanophilous and amyloid skeletal hyphae dissolving in KOH, and non-dextrinoid basidiospores. © 2013 The Authors.

Dong B.-C.,Beijing Forestry University | Zhang M.-X.,Beijing Forestry University | Alpert P.,University of Massachusetts Amherst | Lei G.-C.,Beijing Forestry University | Yu F.-H.,Beijing Forestry University
PLoS ONE | Year: 2010

Background: The ability of small clonal fragments to establish and grow after disturbance is an important ecological advantage of clonal growth in plants and a major factor in the invasiveness of some introduced, clonal species. We hypothesized that orientation in the horizontal position (typical for stoloniferous plants) can increase the survival and growth of dispersed clonal fragments, and that this effect of orientation can be stronger when fragments are smaller and thus have fewer reserves to support initial growth. Methodology/Principal Findings:To test these hypotheses, we compared performance of single-node pieces of stolon fragments of Alternanthera philoxeroides planted at angles of 0, 45 or 90° away from the horizontal position, with either the distal or the proximal end of the fragment up and with either 1 or 3 cm of stolon left attached both distal and proximal to the ramet. As expected, survival and growth were greatest when fragments were positioned horizontally. Contrary to expectations, some of these effects of orientation were stronger when attached stolons were longer. Orientation had smaller effects than stolon length on the performance of fragments; survival of fragments was about 60% with shorter stolons and 90% with longer stolons. Conclusions/Significance: Results supported the hypothesis that orientation can affect establishment of small clonal fragments, suggested that effects of orientation can be stronger in larger rather than smaller fragments, and indicated that orientation may have less effect on establishment than amount of stored resources. © 2010 Dong et al.

Cao H.,U.S. Department of Agriculture | Cao F.,Beijing Forestry University | Roussel A.-M.,Joseph Fourier University | Anderson R.A.,U.S. Department of Agriculture
In Vitro Cellular and Developmental Biology - Animal | Year: 2013

Quantitative real-time PCR (qPCR) such as TaqMan and SYBR Green qPCR are widely used for gene expression analysis. The drawbacks of SYBR Green assay are that the dye binds to any double-stranded DNA which can generate false-positive signals and that the length of the amplicon affects the intensity of the amplification. Previous results demonstrate that TaqMan assay is more sensitive but generates lower calculated expression levels than SYBR Green assay in quantifying seven mRNAs in tung tree tissues. The objective of this study is to expand the analysis using animal cells. We compared both qPCR assays for quantifying 24 mRNAs including those coding for glucose transporter (Glut) and mRNA-binding protein tristetraprolin (TTP) in mouse 3T3-L1 adipocytes and RAW264.7 macrophages. The results showed that SYBR Green and TaqMan qPCR were reliable for quantitative gene expression in animal cells. This result was supported by validation analysis of Glut and TTP family gene expression. However, SYBR Green qPCR overestimated the expression levels in most of the genes tested. Finally, both qPCR instruments (Bio-Rad's CFX96 real-time system and Applied Biosystems' Prism 7700 real-time PCR instrument) generated similar gene expression profiles in the mouse cells. These results support the conclusion that both qPCR assays (TaqMan and SYBR Green qPCR) and both qPCR instruments (Bio-Rad's CFX96 real-time system and Applied Biosystems' Prism 7700 real-time PCR instrument) are reliable for quantitative gene expression analyses in animal cells but SYBR Green qPCR generally overestimates gene expression levels than TaqMan qPCR. © 2013 The Society for In Vitro Biology.

Sun J.,Jiangsu University | Wang R.,Agro Environmental Protection Institute | Zhang X.,Beijing Forestry University | Yu Y.,Jiangsu University | And 3 more authors.
Plant Physiology and Biochemistry | Year: 2013

Hydrogen sulfide (H2S) is emerging as a novel signalling molecule involved in plant growth and responses against abiotic stresses. However, little information is known about its role in cadmium (Cd) detoxification. In the present study, the effects of H2S on Cd toxicity were investigated in Populus euphratica cells using fluorescence imaging technique and a non-invasive vibrating ion-selective microelectrode. Pretreatment with a H2S donor, sodium hydrosulfide (NaHS), significantly mitigated the Cd-induced programmed cell death in P. euphratica cells. The alleviation effect of NaHS was more pronounced at 50-100 μM as compared to low (25 μM) and high doses (200 μM). Under Cd stress, total activities of antioxidant enzymes, such as ascorbate peroxidase, catalase and glutathione reductase, were significantly enhanced in NaHS-treated cells, leading to a decline of H2O2 accumulation and lipid peroxidation. Moreover, NaHS reduced Cd accumulation in the cytoplasm but increased the fraction of Cd in the vacuole. Cd flux profiles revealed that H2S inhibited the Cd influx through the plasma membrane (PM) calcium channels that activated by H2O2. NaHS enhanced Cd influx into the vacuole, and the Cd influx was dependent on the pH gradients across the tonoplast. Taken together, these results suggest that H2S alleviates Cd toxicity via the improvement of antioxidant system and cellular Cd homeostasis. The up-regulation of antioxidant enzymes by H2S reduced the accumulation of H2O2, and thus decreased Cd influx through the H2O2-activated PM calcium channels. The H2S-simulated vacuolar Cd sequestration was presumably due to the activation of tonoplast Cd2+/H+ antiporters. © 2013 Elsevier Masson SAS.

Zhang H.,Beijing Forestry University | Zhang H.,CAS Zhengzhou Research Institute | Lv F.,Beijing Forestry University | Han X.,Beijing Forestry University | And 2 more authors.
Plant Cell Reports | Year: 2013

Key message: This paper is the first to directly link two types of ion channel regulation pathway into an emerging and complex CBL-CIPK signal system in wooden plant. In Arabidopsis thaliana, the calcineurin b-like (CBL) 1 gene has been shown to be necessary in response to abiotic stresses. In this study, we identified CBL1 in the woody plant Populus euphratica, designated as PeCBL1. Heterologous expression of PeCBL1 could build the resistance of sensitive phenotypes to low K+ stress in the corresponding Arabidopsis cbl1/cbl9 mutant, and display a salt-sensitive phenotype compared with the mutant. Protein interaction analysis showed that PeCBL1 can interact with PeCIPK24, 25 and 26, and form different complexes of PeCBL-PeCIPK. To further investigate the mechanism of PeCBL1, we analyzed the fluxes of K+ and Na+ in roots of the wild-type Arabidopsis, cbl1/9 mutant, and PeCBL1 transgenic plants under low K+ stress and high Na+ stress. These analyses revealed that, compared to the cbl1/9 mutant, the PeCBL1 transgenic plant roots exhibited a higher capacity to absorb K+ after exposure to low K+ stress, and a lower capacity to discharge Na+ after exposure to salt stress. The results suggest that CBL1 interacts with CIPK24, CIPK25 and CIPK26 to regulate Na+/K+ homeostasis in Populus euphratica. © 2013 Springer-Verlag Berlin Heidelberg.

Gao Y.,Beijing Forestry University | Zhang Z.,Beijing Forestry University | Wu J.,Beijing Forestry University | Yi X.,CAS Wuhan Center for Magnetic Resonance | And 4 more authors.
Journal of Materials Chemistry A | Year: 2013

Layered double hydroxides (LDHs) have been intensively studied for high-temperature CO2 capture. However, big differences in the CO 2 capture capacity, ranging from 0.28 to 0.6 mmol g-1, have often been reported for the same Mg-Al-CO3 LDH. Furthermore, how the active Mg-O species that are responsible for CO2 adsorption are formed is still unclear. In this work, we have performed a comprehensive investigation on the CO2 adsorption characteristics of Mg-Al-CO 3 LDH-derived mixed metal oxides. Based on these results we proposed the possible adsorption sites and the mechanisms for CO2 adsorption. Initially, the effects of synthesis method, Mg:Al ratio, pretreatment conditions, adsorption conditions, and thermal stability on the CO2 adsorption capacity were systematically studied. By carefully examining the structural changes during thermal treatment using X-ray diffraction and solid state NMR, we suggest that the active Mg-O species could be induced either by the substitution of Mg2+ by Al3+ in the periclase MgO lattice, or by the diffusion of Al3+ out of the octahedral brucite layers. This work not only suggests the optimal testing conditions for LDH-derived CO2 adsorbents, but also provides a clearer understanding of the CO2 adsorption sites and mechanisms on LDH-derived mixed oxides and sheds light on the synthesis and utilization of LDH-derived high-temperature CO2 adsorption materials. © 2013 The Royal Society of Chemistry.

Liu B.,South China University of Technology | Wang X.,South China University of Technology | Yang B.,CAS Guangzhou Institute of Geochemistry | Sun R.,South China University of Technology | Sun R.,Beijing Forestry University
Materials Chemistry and Physics | Year: 2011

A rapid method was developed to prepare organic montmorillonite (organo-MMT) using three novel Gemini surfactants by microwave irradiation of 1 h, which was more effective than conventional heating method of 8-48 h. The structure and morphology of organo-MMTs were characterized by XRD, FT-IR, TEM and SEM. The adsorption amount of Gemini surfactants on MMT and the thermal stability of organo-MMTs were investigated by thermogravimetric analysis (TGA). The results indicated that Gemini surfactants were more efficient than cetyltrimethyl ammonium bromide in the modification of MMT, the organoclays obtained by microwave irradiation method had larger layer spacing than those from traditional heating method. And with the increase of the dosage and chain length of Gemini surfactants, the amount of the intercalary or adsorbed surfactant on the organoclay gradually increased, whereas the thermal stability weakened appropriately. Besides, the adsorption results for methyl orange indicated that all organo-MMTs displayed more excellent adsorption capacities than unmodified MMT. The amount of methyl orange adsorbed onto the organo-MMTs increased proportionately with the increase of the amount or the chain length of Gemini surfactants. This study affords a rapid and efficient method to obtain the organoclay with large interlayer distance and strong adsorption capacity. © 2011 Elsevier B.V. All rights reserved.

Dong B.-C.,Beijing Forestry University | Alpert P.,University of Massachusetts Amherst | Guo W.,Beijing Forestry University | Yu F.-H.,Beijing Forestry University
Biological Invasions | Year: 2012

The capacity of small clonal fragments to survive and grow is a major factor in the spread of clonal plants, especially aquatic species. This study of the introduced, invasive, amphibious, stoloniferous herb Alternanthera philoxeroides in China tested the effects of fragment size, of loss of the stolon apex, and of the original position of a fragment within a clone before fragmentation on the survival and growth of fragments in a greenhouse experiment. The stolon internodes of plants consisting of one stolon with 5 ramets were severed in all 16 possible patterns, generating fragments of 1-5 ramets. These 16 fragmentation treatments were crossed with removal of the stolon apex. Fragmentation and apex removal did not affect total growth of plants, but more highly fragmented plants produced smaller, more numerous ramets. The survival of fragments consisting of one original ramet was about 85%, compared to 100% survival of fragments with 5 original ramets. Fragments consisting of the youngest ramets along the original stolon grew more than fragments of the same size that consisted of older ramets. These effects of fragmentation on growth provide new evidence for clonal integration of the rate at which connected ramets produce new ramets and novel evidence that fragments produced from different portions of clones have different potential for spread. They further suggest that detachment of small groups of distal ramets along stolons in the field might be very effective in spreading the species and that a trade-off between the number and the size of new ramets produced by fragments may represent an adaptive, plastic response to disturbance. Results do not recommend intentional fragmentation of clones as a means of controlling the rate of growth of this invasive species but suggest that incidental fragmentation may not increase its growth in mass, although it may increase its rate of spread. © 2011 Springer Science+Business Media B.V.

Lin H.-F.,Beijing Forestry University | Alpert P.,University of Massachusetts Amherst | Yu F.-H.,Beijing Forestry University
Aquatic Botany | Year: 2012

Many aquatic, clonal plants spread by vegetative fragments consisting of one to several ramets. Fragment size and physiological integration between ramets are likely to affect the establishment and growth of these fragments, and water depth is likely to affect the success of fragments in aquatic species that root in the sediment, but these effects have been little studied. To test the hypotheses that larger fragments perform better, that fragments perform better in shallower water, and that integration produces differences in the growth of ramets within fragments, we grew stem fragments of the cultivated, invasive, amphibious, floating, rooting plant Ipomaea aquatica with 1, 2, 3, or 4 nodes, which function as ramets, in water depths of 5, 20, or 40cm for 8 weeks in the greenhouse. Final mean mass and leaf area per node were greater in larger fragments (e.g., 0.46g and 49.3cm 2 in 4-node versus 0.16g and 18.5cm 2 in 2-node fragments). Fragments accumulated about 3 times more mean biomass and leaf area in 5cm (1.78g and 196.7cm 2) than in 20cm (0. 49g and 49.9cm 2) or 40cm (0.36g and 34.9cm 2) deep water. Within larger fragments, most of the mean final mass was contained in the youngest ramet (66% in 3-node and 67% in 4-node fragments). Results supported all three hypotheses, and suggest that only stem fragments with 2 or more nodes are likely to promote vegetative reproduction in I. aquatica, and that physiological integration may concentrate growth in younger ramets. © 2012 Elsevier B.V..

Xiong D.,Beijing Forestry University | Wang Y.,Beijing Forestry University | Ma J.,Beijing Forestry University | Klosterman S.J.,U.S. Department of Agriculture | And 2 more authors.
BMC Genomics | Year: 2014

Background: Verticillium dahliae is a soil-borne fungus that causes vascular wilt diseases in a wide range of plant hosts. V. dahliae produces multicelled, melanized resting bodies, also known as microsclerotia (MS) that can survive for years in the soil. The MS are the primary source of infection of the Verticillium disease cycle. Thus, MS formation marks an important event in the disease cycle of V. dahliae.Results: In this study, next generation sequencing technology of RNA-Seq was employed to investigate the global transcriptomic dynamics of MS development to identify differential gene expression at several stages of MS formation in strain XS11 of V. dahliae, isolated from smoke tree. We observed large-scale changes in gene expression during MS formation, such as increased expression of genes involved in protein metabolism and carbohydrate metabolism. Genes involved in glycolytic pathway and melanin biosynthesis were dramatically up-regulated in MS. Cluster analyses revealed increased expression of genes encoding products involved in primary metabolism and stress responses throughout MS development. Differential expression of ubiquitin-dependent protein catabolism and cell death-associated genes during MS development were revealed. Homologs of genes located in the lineage-specific (LS) regions of V. dahliae strain VdLs.17, were either not expressed or showed low expression. Furthermore, alternative splicing (AS) events were analyzed, revealing that over 95.0% AS events involve retention of introns (RI).Conclusions: These data reveal the dynamics of transcriptional regulation during MS formation and were used to construct a comprehensive high-resolution gene expression map. This map provides a key resource for understanding the biology and molecular basis of MS development of V. dahliae. © 2014 Xiong et al.; licensee BioMed Central Ltd.

Matin M.A.,University of New Brunswick | Bourque C.P.-A.,University of New Brunswick | Bourque C.P.-A.,Beijing Forestry University
Journal of Arid Environments | Year: 2015

The paper examines the role of mountain runoff in the seasonal growth of oasis vegetation in the hyper-arid region of northwest China. Central to this examination is the development of a simple hydrologic model that relates hydrologic inflows and outflows estimated from remote sensing data (e.g., evapotranspiration, precipitation, snow accumulation, and snowmelt) to the calculation of runoff over a ten-year period (2000-2009). Modeled runoff is shown to reproduce the seasonal trends in hydrometric data fairly well, yielding R2's of 0.75 and 0.66 for stations in the upper reaches of the Shiyang and Hei River systems. Greater than 90% of the runoff from the Qilian Mountains to the oases occurs during the May-September period. Considerable discrepancy between modeled and observed runoff exists in the lower reaches of the rivers, where significant amounts of river water (>45%) are routinely extracted for cropland irrigation. Along the river systems, where water extraction and inflow of glacial meltwater are minor, model calculations replicate observed water yields much more closely. Analysis of seasonal trends in the contribution of snowmelt and rainfall to the return flow, reveals snowmelt as having the greatest influence in initiating the oasis growing period during the March-to-May period of each year. © 2015 Elsevier Ltd.

Yuan T.,Beijing Forestry University | Wang L.Y.,Beijing Forestry University | Roh M.S.,U.S. Department of Agriculture
Scientia Horticulturae | Year: 2010

The hybrid origin of progeny from crosses of Clematis tubulosa and Clematis brevicaudata was investigated using randomly amplified polymorphic DNA (RAPD) and single nucleotide polymorphisms (SNPs) from sequence analysis of chloroplast rbcL, accD genes, and the C. brevicaudata matK gene. Plants collected from three and four populations of C. brevicaudata (C. brev) and C. tubulosa (C. tubu), respectively, from Mt. Songshan, Beijing, China were used as parents for hybridization. Morphological characters of pollen, seeds, and leaves were recorded in 2007. DNA from leaf samples of both parents and of C. brev × C. tubu and C. tubu × C. brev were extracted, and used for RAPD and SNPs from sequence data. A dendrogram was constructed by the branching neighbor-joining (IB-NJ) method. Proportionate population scores were generated by the admixture model using the STRUCTURE software. Based on morphological characters, C. brevicaudata was quite uniform. However, variations were detected in C. tubulosa. Hybrids of C. brev × C. tubu and C. tubu × C. brev showed intermediate morphological characters of the parents. Accessions of C. tubu × C. brev were clustered into 2 groups, with the majority of hybrids belonging to group IV b in the RAPD dendrogram, suggesting that this resulted from variations within C. tubulosa. In general, the hybrid origin of all progeny characterized by morphological characters was supported by the RAPD and SNPs data. These results indicate that RAPD results supported by SNPs data will be useful tool to verify hybrids.