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Liu X.-Q.,Zhengzhou University | Li Z.-Y.,Shenzhen Academy of Metrology and Quality Inspection | Yuan X.-J.,Zhengzhou University | Wu B.-L.,Zhengzhou University
Journal of Coordination Chemistry | Year: 2012

A purine-containing multifunctional ligand, 2-(6-oxo-6H-purin-1(9H)-yl) acetic acid (HL), and two new 2-D coordination polymers, [Co(L) 2(H 2O) 2] n2nH 2O (1) and [Ni(L) 2(H 2O) 2] n2nH 2O (2), were synthesized and characterized. Polymers 1 and 2 have isomorphous structures with (4,4)-connected topologies composed of left- and right-handed metal-organic helices sharing common metal centers. Two helical conformations in the same net are stabilized by strong π-π stacking interactions between purine groups. Through direct and water-mediated interlayer hydrogen-bond interactions those layers are assembled into stable 3-D supermolecules where slight differences in the strength of hydrogen bonds and coordination bonds result in their decomposition behaviors. © 2012 Taylor and Francis.

Chen Z.,Guilin University of Technology | Li Y.,Shenzhen Academy of Metrology and Quality Inspection | Lin S.,Hong Kong Baptist University | Wei M.,Guilin University of Technology | And 2 more authors.
Biochemical and Biophysical Research Communications | Year: 2014

In this study, an easy and efficiency protein digestion method called continuous microwave-assisted protein digestion (cMAED) with immobilized enzyme was developed and applied for proteome analysis by LC-MSn. Continuous microwave power outputting was specially designed and applied. Trypsin and bromelain were immobilized onto magnetic micropheres. To evaluate the method of cMAED, bovine serum albumin (BSA) and protein extracted from ginkgo nuts were used as model and real protein sample to verify the digestion efficiency of cMAED. Several conditions including continuous microwave power, the ratio of immobilized trypsin/BSA were optimized according to the analysis of peptide fragments by Tricine SDS-PAGE and LC-MSn. Subsequently, the ginkgo protein was digested with the protocols of cMAED, MAED and conventional heating enzymatic digestion (HED) respectively and the LC-MSn profiles of the hydrolysate was compared. Results showed that cMAED combined with immobilized enzyme was a fast and efficient digestion method for protein digestion and microwave power tentatively affected the peptide producing. The cMAED method will be expanded for large-scale preparation of bioactive peptides and peptide analysis in biological and clinical research. © 2014 Elsevier Inc. All rights reserved.

Guan Y.,Tianjin University | Yin Y.,Shenzhen University | Li A.,Shenzhen Academy of Metrology and Quality Inspection | Liu X.,Shenzhen University | And 2 more authors.
Optics Letters | Year: 2014

An acoustic-optics heterodyne fringe interferometry coupled with a three-camera system is developed for dynamic 3D imaging. In this system, first-order beams with a slight frequency difference diffracted from two acousto-optic deflectors (AODs) form a beat intensity fringe pattern. Setting the frequency of the trigger signal for the CCD cameras into four times the beat frequency, four-step phase-shifting fringe patterns can be obtained, and the wrapped phase map (WPM) can be calculated. Under the epipolar constraint among three cameras, the homologous points can be determined unambiguously with the assistant of a WPM; thus the 3D shape can be reconstructed while skipping the phase unwrapping step. Experimental results are presented to validate this approach. © 2014 Optical Society of America.

Lu B.,Japan National Institute of Environmental Studies | Li Z.,Shenzhen Academy of Metrology and Quality Inspection | Kawamoto K.,Japan National Institute of Environmental Studies
Materials Research Bulletin | Year: 2013

The synthesis of mesoporous ceria (CeO2) without a template was studied in detail using NaOH and NH4OH solution. We first synthesized nanosized mesoporous CeO2 without a template by the direct hydrothermal synthesis method with NaOH. By using NaOH, mesoporous CeO 2 could be obtained without a template through the oxidation of Ce3+ ions, the hydrolysis of Ce4+ ions, polymerization and precipitation. Under appropriate synthesis conditions, the obtained mesoporous CeO2 had a high surface area, a narrow pore size distribution and an ordered structure with uniform mesopores. The surface area of the mesoporous CeO2 increased with increasing synthesis temperature. The NaOH concentration induced different behavior on the mesoporous CeO2 surface with and without a template. The mesoporous CeO2 had nanoarrays with uniform mesopores (intercrystalline voids). However, when NH4OH solution was used, the CeO2 had nanoarrays with a hierarchical pore network. The mesoporous CeO2 obtained without template had relatively high thermal stability that increased with increasing synthesis temperature. © 2013 Elsevier Ltd. All rights reserved.

Li Q.,Shenzhen Academy of Metrology and Quality Inspection | You J.,Hong Kong Polytechnic University | Zhang D.,Hong Kong Polytechnic University
Expert Systems with Applications | Year: 2012

Automated segmentation of blood vessels in retinal images can help ophthalmologists screen larger populations for vessel abnormalities. However, automated vessel extraction is difficult due to the fact that the width of retinal vessels can vary from very large to very small, and that the local contrast of vessels is unstable. Further, the small vessels are overwhelmed by Gaussian-like noises. Therefore the accurate segmentation and width estimation of small vessels are very challenging. In this paper, we propose a simple and efficient multiscale vessel extraction scheme by multiplying the responses of matched filters at three scales. Since the vessel structures will have relatively strong responses to the matched filters at different scales but the background noises will not, scale production could further enhance vessels while suppressing noise. After appropriate selection of scale parameters and appropriate normalization of filter responses, the filter responses are then extracted and fused in the scale production domain. The experimental results demonstrate that the proposed method works well for accurately segmenting vessels with good width estimation. © 2012 Elsevier Ltd. All rights reserved.

Li Q.,Shenzhen University | Wang H.J.,Hong Kong Polytechnic University | You J.,Hong Kong Polytechnic University | Li Z.M.,Shenzhen Academy of Metrology and Quality Inspection | Li J.X.,Shenzhen University
PLoS ONE | Year: 2013

In some large-scale face recognition task, such as driver license identification and law enforcement, the training set only contains one image per person. This situation is referred to as one sample problem. Because many face recognition techniques implicitly assume that several (at least two) images per person are available for training, they cannot deal with the one sample problem. This paper investigates principal component analysis (PCA), Fisher linear discriminant analysis (LDA), and locality preserving projections (LPP) and shows why they cannot perform well in one sample problem. After that, this paper presents four reasons that make one sample problem itself difficult: the small sample size problem; the lack of representative samples; the underestimated intra-class variation; and the overestimated inter-class variation. Based on the analysis, this paper proposes to enlarge the training set based on the inter-class relationship. This paper also extends LDA and LPP to extract features from the enlarged training set. The experimental results show the effectiveness of the proposed method. © 2013 Li et al.

Liu Y.,Shenzhen Academy of Metrology and Quality Inspection | Yang Z.,Shenzhen Academy of Metrology and Quality Inspection
Advanced Materials Research | Year: 2013

In this paper, a research approaching on nano-TiO2 particles modified fabric functional enhancement is reported. The morphologies of the nano particles existing on the fabric surface were examined by scanning electron microscopy (SEM), which showed that the particle size is less than 100nm and almost no coacervation, and then water-repellent and oil-repellent performance of the modified fabric was measured by the contact angle method, and found they had the most desired water and oil release behaviors. In addition, the modified fabric showed excellent antibacterial effects according to FZ/T73023-2006 antibacterial standard, and the antibacterial efficiency was above 95%. Meanwhile, good durability of functional fabrics also observed which could endure 20 times washing at least. © (2013) Trans Tech Publications, Switzerland.

Wang X.,Shenzhen Academy of Metrology and Quality Inspection | Xing Y.-N.,Shenzhen Academy of Metrology and Quality Inspection | Chen Z.-Y.,Shenzhen Academy of Metrology and Quality Inspection | Lin H.-X.,Shenzhen Academy of Metrology and Quality Inspection
Journal of Chinese Mass Spectrometry Society | Year: 2013

A method for determinating trace migratory organo-tin in toys by high perform-ance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was developed. The organo-tin species dibutyltin(DBT), triphenyltin(TPhT), tributyltin (TBT) and dioctyltin(DOT) were separated on Waters Acquity UPLC HSS T3analysis column using the mobile phase of V(acetonitrile) : V(water) : V(acetic acid)=65:23:12, 0.1% triethylamine with pH 3.0.This method is quickly and high sensitivity. The detection limits are 0.08, 0.24, 0.14 and 0.65 μg/L for DBT, TPhT, TBT and DOT with injection volume of 50 μL. The recoveries are 80.7%-96.3% and 83.5%-100.4% for the spiked levels of 5 and 50 μg/L, and the RSDs are less than 47%, which meet the determination requirements. This method has been used to determine migratory organo-tin in accessible parts of toys, including coating, plastic, wood and textile.

Zhang S.,Shenzhen Academy of Metrology and Quality Inspection | Lai X.,Shenzhen Academy of Metrology and Quality Inspection | Yang G.,Shenzhen Academy of Metrology and Quality Inspection
Journal of Immunoassay and Immunochemistry | Year: 2013

A hen's egg is one of the most common causes of food allergy. The allergen quantitation in hot-processed food is always a difficult task, because the protein in these samples will be denatured, insoluble, and degraded. This article presents a competitive enzyme linked immunosorbent assay (ELISA) for the quantitation of ovalbumin in hot-processed food. Its recovery was improved nearly two times by the assay method as compared with previous sandwich ELISA. The heat and DL-Dithiothreitol treated ovalbumin was used as antigen for monoclonal antibody preparation. A smaller labeled antibody molecule, horseradish peroxidase (HRP) labeled Fab fragment, was used to replace IgG in ELISA for improving sensitivity and analytical speed of the method. A binding site protection procedure was developed for Fab fragment labeling with HRP, which prevented damage to the Fab binding site. The combination and separation steps were efficiently completed in an affinity spin column. Based on the optimized ELISA condition, the IC50 was 1.2 μg/mL and the coefficients of variation were less than 10%. Copyright © Taylor & Francis Group, LLC.

PubMed | Guilin University of Technology and Shenzhen Academy of Metrology and Quality Inspection
Type: | Journal: Food chemistry | Year: 2017

A novel continuous microwave-assisted enzymatic digestion (cMAED) method is proposed for the digestion of protein from Scomberomorus niphonius to obtain potential antioxidant peptides. In this study, bromelain was found to have a high capacity for the digestion of the Scomberomorus niphonius protein. The following cMAED conditions were investigated: protease species, microwave power, temperature, bromelain content, acidity of the substrate solution, and incubation time. At 400W, 40C, 1500Ug

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