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Lv F.,Beijing University of Chemical Technology | Liang H.,Beijing University of Chemical Technology | Yuan Q.,Beijing University of Chemical Technology | Li C.,Beijing Industrial Technician College
Food Research International | Year: 2011

The aim of this study was to evaluate the antimicrobial efficacy of selected plant essential oil (EO) combinations against four food-related microorganisms. Ten EOs were initially screened against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Saccharomyces cerevisiae using agar disk diffusion and broth dilution methods. The highest efficacy against all the tested strains was shown when testing the oregano EO. EOs of basil and bergamot were active against the Gram-positive bacteria (S. aureus and B. subtilis), while perilla EO strongly inhibited the growth of yeast (S. cerevisiae). The chemical components of selected EOs were also analyzed by GC/MS. Phenols and terpenes were the major antimicrobial compounds in oregano and basil EOs. The dominant active components of bergamot EO were alcohols, esters and terpenes. For perilla EO, the major active constituents were mainly ketones. The checkerboard method was then used to investigate the antimicrobial efficacy of EO combinations by means of the fractional inhibitory concentration index (FICI). Based on an overall consideration of antimicrobial activity, organoleptic impact and cost, four EO combinations were selected and their MIC values were listed as follows: oregano-basil (0.313-0.313 μl/ml) for E. coli, basil-bergamot (0.313-0.156 μl/ml) for S. aureus, oregano-bergamot (0.313-0.313 μl/ml) for B. subtilis and oregano-perilla (0.313-0.156 μl/ml) for S. cerevisiae. Furthermore, the mechanisms of the antimicrobial action of EO combinations to the tested organisms were studied by the electronic microscopy observations of the cells and the measurement of the release of cell constituents. The electron micrographs of damaged cells and the significant increase of the cell constituents' release demonstrated that all EO combinations affected the cell membrane integrity. © 2011 Elsevier Ltd.

Hu X.,Beijing University of Chemical Technology | Li H.,Beijing University of Chemical Technology | Tang P.,Beijing University of Chemical Technology | Sun J.,Beijing University of Chemical Technology | And 2 more authors.
Fungal Genetics and Biology | Year: 2013

The potential use of arachidonic acid (AA) to enhance the production of β-carotene in Blakeslea trispora was investigated in this work. To study the mechanism of the B. trispora response to AA, we used a systematic analytical approach to investigate the changes in the B. trispora cell metabolome at different time points after AA treatment. A maximum of β-carotene production was obtained when 0.4. g/l AA was added after 36. h of cultivation. Gas chromatography-mass spectrometry (GC-MS)-based metabolomics approach and a multivariate analysis were used to investigate the intracellular biochemical changes in B. trispora. With the aid of principal component analysis (PCA), the intracellular metabolite profiles of all the groups were distinguished. Moreover, a group classification and pairwise discrimination between the control and AA-treated groups were obtained through partial least-squares-discriminant analysis (PLS-DA), and 27 differential metabolites with variable importance in the projection (VIP) value higher than 1 were identified, which was also confirmed by the subsequent hierarchical cluster analysis (HCA). Separation of the control and AA-treated groups was mainly due to the compounds of the Krebs cycle, fatty acids and amino acids. With the treatment of AA, the glycolysis was enhanced and the use of glucose for fermentation was increased. The increased levels of some fatty acids and decreased levels of amino acids in the AA-treated cells could also be the responses to the addition of AA. Metabolomics provided a powerful methodology to gain insight in metabolic changes induced by metabolic stimulators in microorganisms. © 2013 Elsevier Inc.

Hu J.,Beijing University of Chemical Technology | Li H.,Beijing University of Chemical Technology | Yang Y.,Beijing University of Chemical Technology | Wang S.,Beijing University of Chemical Technology | And 4 more authors.
RSC Advances | Year: 2015

Alpha-linolenic acid (ALA) is known for its ability to promote the production of β-carotene in Blakeslea trispora. However, the mechanism is still poorly understood. In this study, gas chromatography-mass spectrometry (GC-MS)-based metabolomic approach and multivariate analysis were used to study mechanisms underlying the regulation effects of ALA on β-carotene synthesis in B. trispora. ALA treatment promoted the biomass of B. trispora and β-carotene production. The maximum β-carotene production 5.344 mg L-1 was realized after 72 h of cultivation in the presence of 50 μL ALA. The intracellular metabolite profiles found upon treatment of the cells with different addition time points of ALA were unique and could be distinguished from the aid of principal component analysis (PCA). Furthermore, partial least-squares-discriminant analysis (PLS-DA) revealed a group classification and pairwise discrimination between the control and ALA treated groups, and 28 differential metabolites with variable importance in the projection (VIP) value greater than 1. The addition of ALA decreased the glycolysis, TCA cycle and fatty acid synthesis. The accumulation of linolenic acid and linoleic acid indicated that ALA was directly absorbed by the fungus and transformed into its own linolenic acid. As a result, the flux from acetyl-CoA to β-carotene synthesis increased. Besides, the addition of ALA increased the level of dissolved oxygen and the production of β-carotene. © 2015 The Royal Society of Chemistry.

Zhou X.-J.,Beijing Forestry University | Zhou X.-J.,Beijing Center for Physical and Chemical Analysis | Li K.,Beijing Forestry University | Fan H.,Beijing Forestry University | And 4 more authors.
Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University | Year: 2015

We applied soxhlet extraction to obtain seed oil of 17 kinds of germplasm from 11 different areas of China, belonging to five varieties of the genus Perilla and then used GC-MS to analyze the amounts of oil as well as the composition and relative amounts of fatty acids. Fourteen fatty acids were indentified from P. frutescens seed oil. These were divided into two groups of six high level (0.8%) and eight low level (≤0.2%) amounts of fatty acids. For the first time 14-methyl-hexadecanoic acid (C17:0), 18 carbon diene acid (C18:2n3) and 23 carbon acid (C23:0) were reported in P. frutescens oil. The relative amount of α-linolenic acid was the highest with a range of 51.92% to 62.98%. Certain metabolic conversion relationships were detected among α-linolenic, linoleic and oleic acids. The results calculated with an external standard method for the amount of fatty acids in P. frutescens seeds implies that P. frutescens var. frutescens, among the five varieties investigated, is preferable as the raw material for P. frutescens oil, given its high rate of oil rate and its amount of α-linolenic acid. ©, 2015, Beijing Forestry University. All right reserved.

PubMed | Beijing Industrial Technician College, Beijing Center for Physical and Chemical Analysis and Beijing University of Chemical Technology
Type: Journal Article | Journal: Molecules (Basel, Switzerland) | Year: 2017

In this paper we report a facile method for preparing co-immobilized enzyme and magnetic nanoparticles (MNPs) using metal coordinated hydrogel nanofibers.

Yao M.,Beijing University of Technology | Zhang W.,Beijing University of Technology | Yao Z.,Beijing Industrial Technician College
Journal of Vibration and Acoustics, Transactions of the ASME | Year: 2015

This paper investigates the complicated dynamics behavior and the evolution law of the nonlinear vibrations of the simply supported laminated composite piezoelectric beam subjected to the axial load and the transverse load. Using the third-order shear deformation theory and the Hamilton's principle, the nonlinear governing equations of motion for the laminated composite piezoelectric beam are derived. Applying the method of multiple scales and Galerkin's approach to the partial differential governing equation, the four-dimensional averaged equation is obtained for the case of principal parametric resonance and 1:9 internal resonance. From the averaged equations obtained, numerical simulation is performed to study nonlinear vibrations of the laminated composite piezoelectric beam. The axial load, the transverse load, and the piezoelectric parameter are selected as the controlling parameters to analyze the law of complicated nonlinear dynamics of the laminated composite piezoelectric beam. Based on the results of numerical simulation, it is found that there exists the complex nonlinear phenomenon in motions of the laminated composite piezoelectric beam. In summary, numerical studies suggest that periodic motions and chaotic motions exist in nonlinear vibrations of the laminated composite piezoelectric beam. In addition, it is observed that the axial load, the transverse load and the piezoelectric parameter have significant influence on the nonlinear dynamical behavior of the beam. We can control the response of the system from chaotic motions to periodic motions by changing these parameters. Copyright © 2015 by ASME.

Ren F.,Northeast Petroleum University | Chen S.,Northeast Petroleum University | Yao Z.,Beijing Industrial Technician College
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2013

A flexible drill string in horizontal well was simplified as an axial load of elongated flexible beam. Nonlinear dynamic equations were established about the geometric large deformation, transverse vibration average equations of the beam were received by using the method of multiple scales. Due to the rotation speed and the axial force had the same role in the average equation, so nonlinear dynamic responses were analyzed by changing the rotating speed in the average equations. The bifurcation graphs for first and second order modes and phase diagram of different speeds were given. The analysis results show that the whole responses of system has gone through the process of cycle-chaos-twice the cycle, along with the response amplitudes there are jumping phenomena, and the amplitude of the rotating flexible beam actually is not infinite, but limited value in the resonance condition. Therefore, when the axial force changes, vibration of the flexible beam can be controlled by controlling its rotation speed quantitatively and qualitatively.

Ren F.,Northeast Petroleum University | Chen S.,Northeast Petroleum University | Yao Z.,Beijing Industrial Technician College
Applied Mechanics and Materials | Year: 2012

This paper studies the complex transverse vibration behavior of drill string. The drill string was simplified as flexible rotation beam, and drill string of complex load was simplified for flexible rotation beam system. The nonlinear dynamic equations of flexible rotation beam is established and the complex dynamic response of flexible rotation beam in resonance case is analyzed by using method of nonlinear dynamics method. Research result show that the chaotic responses are sensitive to the revolving speed, the nonlinear oscillation of drilling string can be controlled by changing the rotating speed. This study has guiding significance to keep sidewall stability in the process of horizontal wells of sidetrack, improve the drilling rate and reduce the cost of the drilling. © (2012) Trans Tech Publications, Switzerland.

Gao S.-J.,Beijing Forestry University | Gao S.-J.,Beijing University of Civil Engineering and Architecture | Zhao C.,Beijing University of Civil Engineering and Architecture | Shi Z.-H.,Beijing Industrial Technician College | And 3 more authors.
Journal of Analytical Methods in Chemistry | Year: 2016

In this study, soil samples collected from different plain afforestation time (1 year, 4 years, 10 years, 15 years, and 20 years) in Miyun were characterized, including total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), available K (K+), microbial biomass carbon (MBC), and dissolved organic carbon (DOC). The DOM in the soil samples with different afforestation time was further characterized via DOC, UV-Visible spectroscopy, excitation-emission matrix (EEM) fluorescence spectroscopy, and 1H NMR spectroscopy. The results suggested that the texture of soil sample was sandy. The extracted DOM from soil consisted mainly of aliphatic chains and only a minor aromatic component. It can be included that afforestation can improve the soil quality to some extent, which can be partly reflected from the indexes like TOC, TN, TP, K+, MBC, and DOC. And the characterization of DOM implied that UV humic-like substances were the major fluorophores components in the DOM of the soil samples, which consisted of aliphatic chains and aromatic components with carbonyl, carboxyl, and hydroxyl groups. © 2016 Shi-Jie Gao et al.

Ren F.-S.,Northeast Petroleum University | Yao Z.-G.,Beijing Industrial Technician College
Gongcheng Lixue/Engineering Mechanics | Year: 2013

In drilling process of horizontal wells, the transverse vibration of drill string likely occur due to axial compression, which may cause serious accidents such as drill string failure and hole expanding etc. In this paper, the compressive-drill string is simplified as a revolving flexible beam subjected to a load condition simplified from complicated excitations of drill string. Thus, the nonlinear dynamic model of flexible drill string is established based on the von Karman theory, where the partial differential equation is discreted by Galerkin method, and then the nonlinear control equation of drill string is acquired, and the average equation is obtained by multiscale method. The complex behaviour of flexible drilling string in resonance is analyzed by nonlinear dynamic method, and the dependence of nonlinear dynamics responses on rotating speed is investigated. The research results will provide a theoretical basis for the practical efforts of decreasing failure rate, improving drilling rate and reducing drilling cost during the drilling process of horizontal well.

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