2017 Vol. 32, No. 6
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A total of 88 pure cultures was obtained from the pit muds of one wine corporation following separation and purification culture. The 75 strains of bacteria were assigned into 8 phylogenetic clusters (cluster Ⅰ-Ⅷ) based on the analysis of 16S rRNA gene sequences and phylogenetic tree. In them, the most similar bacteria were C. tyrobutyricum, C. butyricum, C. indolis, C. acetobutylicum, C. bifermentans, C. sporogenes, C. cadaveris and C. kluyveri, respectively. The volatile metabolites of 8 representative Clostridium spp. were analyzed using headspace solid-phase microextraction (HS-SPME) method followed by gas chromatography-mass spectrometry (GC-MS). A total of 75 volatile metabolites was detected, including 23 alcohols,20 acids,14 esters,2 aldehydes,2 ketones and other 14 volatile substances. The principal component analysis revealed that the representative strain RL1 (C. tyrobutyricum) and EL7 (C. butyricum) were mainly related to the generation of acetic acid and butyric acid, and EL46 (C. kluyveri), RL20 (C. acetobutylicum) and RL10 (C. indolis) mainly contributed to the formation of caproic acid and ethyl hexanoate, and EL12 (C. bifermentans) and RL23 (C. sporogenes) were mainly associated with the S-methyl acetate, 1-Decyl alcohol and octanol, and EL43 (C. cadaveris) was mainly correlated to the biosynthesis of various esters.
The caproic acid-producing and lactic acid-utilizing consortiums were constructed based on microbe in pit muds of Luzhou-flavor liquor from one wine corporation in He'nan. The prokaryotic microbial community was analyzed using high-throughput sequencing based on the V4 variable regions of 16S rRNA gene. The results showed that the species diversities in both constructed consortiums were lower than those in pit muds, which was accompanied by the obvious changes in composition of dominant microbe. The dominant prokaryotes in the caproic acid-producing consortiums were the Firmicute Clostridium and Ruminococcus. The dominant prokaryotes in the lactic acid-utilizing consortiums belonged to the Firmicute Bacillus, Clostridium, Sporanaerobacter, Soehngenia, Oscillospira, Ruminococcus, Paenibacillus, Caldicoprobacter, Sedimentibacter, Dorea, Coprococcus and Tepidimicrobium. This study will be conducive to clarify the taxonomic status of caproic acid-producing and lactic acid-utilizing consortiums in pit muds, and provide theoretical support for realizing caproic acid-producing and lactic acid-utilizing in production of Luzhou-flavor liquor through microbial directional bioaugmentation.
Using the metagenomic high-throughput sequencing technology,the sequencing analysis of the V3-V4 variable regions of 16S rRNA gene of the grape surface microbe of marketed Summer Black Seedless variety was conducted. The results showed that the the grape surface microbes were highly diverse consortium and had obviously dominant microflora. At the phylum level, the dominant microbes were Firmicutes and Proteobacteria. At the class level, the dominant microbes were α,β,γ-Mycetozoan, Clostridium and Actinomycetes. At the genus level, the dominant microbe was Lactococcus. Furthermore, the pathogenic bacteria Escherichia-Shigella was detected on the grape surface of marketed Summer Black Seedless variety.This study is of reference significance for biological control after fruit picking and inspectation and quarrantine of market fruit.
With HEMA and DMC as comonomers, the water-soluble copolymer mercapto-poly (methacrylic acid-β-hydroxyethyl (HS-P (HEMA-co-DMC)) containing hydroxyl, mercapto and ammonium cations in the side chain was prepared by free radical polymerization and sulfhydryl conversion reaction. The rheological properties and morphology of the two types of composite hydrogels, which were formed by HS-P (HEMA-co-DMC) reacting respectively with polyethylene glycol diacrylate (PEGDA) and surface-loaded laponite (Laponite RD) by the physical/chemical cross-linking reaction, were measured by rheometry and SEM.The results showed that the gel storage modulus and loss factor of HS-P (HEMA-co-DMC)/LaponiteRD composite hydrogel were respectively 3468 Pa and 0.34 with a solid content of 22%, showing obvious viscoelastic behavior of the crosslinked points. At the same solid content, HS-P ((HEMA-co-DMC)/PEGDA composite hydrogel had a storage modulus of 1484 Pa and a loss factor of 0.013, showing the viscoelastic behavior of a typical covalently crosslinked gel. HS-P ((HEMA-co-DMC)/Laponite RD composite hydrogel had a denser pore structure than HS-P (HEMA-co-DMC)/PEGDA composite hydrogel.
Dual-network hydrogels with high elasticity were prepared by oxidation/reduction (Fe2+/ammonium persulfate) initiation system using acrylic acid and agar as the main raw materials.The optimum conditions were obtained as follows:agar mass concentration was 1%,masacrylic acid concentration was 30% (mass fraction),ammonium persulfate concentration was 1.5% (mass fraction),N,N'-Methylenebisacrylamide concentration was 0.3% (mass fraction),and ferrous sulfate concentration was 0.050% (mass fraction).Through the analysis of the mechanical properties of the gel,it was found that the tensile elongation of the gel was 225% and the compressive capacity was 4 MPa,exhibiting good stretch and compression performance.The microstructure of the hydrogel were analyzed by IR using SEM.The results showed that the hydrogel has a fiber network structure with a fiber diameter of about 100 nm, there was intermolecular hydrogen bonding between agar and polyacrylic acid and the metal complexation between Fe3+ and polyacrylic acid molecules.
The research progresses of hydrogels applied to slow/controlled release fertilizers were reviewed.It was found that water retention and slow/controlled fertilizer with distinguished properties could be obtained by applying hydrogels to slow/controlled fertilizer, resulting in raising utilization rate of fertilizer and water resources at the same time; and the limitations to the wide application of water retention and slow/controlled fertilizer were high cost, unsuitable to industrial production and difficult to realize the complete accord between release circle of fertilizer and demand circle of crops to nutrients. By exploring mechanism and laws of fertilizer release and controlling structure and component of fertilizer, especially structure and component of hydrogels, tuning its release properties, smart retention and slow/controlled fertilizer system could be fabricated. The fertilizer system can satisfy the need of different surroundings and the growth of different crops, which will be the further focus and direction of research.
Tobacco leaf protein was extracted by alkali-solution and acid-isolation method from upper leaves in the field. The tobacco protein was hydrolyzed using trypsin, papain or protamex, respectively. The effect of different enzymolysis conditions on leaf protein hydrolysis degree and the DPPH clearance rate of tobacco leaf protein polypeptide were investigated. The results showed that the optimal enzymolysis conditions of protein peptide were different with those of the highest DPPH clearance rate of protein polypeptide. Using papain as an example, the optimal hydrolysis conditions for tobacco protein hydrolysis degree were enzymolysis temperature 50℃, hydrolysis time 0.5 h, enzyme amount 3%, pH=8. The optimal hydrolysis conditions for DPPH clearance rate were temperature 40℃, enzymolysis time 2 h, enzyme amount 3%, pH=7. This indicated that the degree of hydrolysis of protein polypeptide was not positively correlated with its antioxidant activity. Protein peptide can be used as substrate for Maillard reaction or antioxidant, and it may be chosen corresponding optimal enzymatic conditions for different purposes.
A method for determination of the content of neutral aromatic components from cigarette mainstream smoke by semi-preparative high performance liquid chromatography (semi-preparative HPLC) coupled with gas chromatography-mass spectrometry (GC-MS) was developed:the fraction collection time was determined to three time periods by optimizing the conditions of semi-preparative HPLC in order to ensure that the compounds to be measured don't cross in the fractions. The selected ion chromatogram showed that all target compounds could be separated completely in three fractions and the method could satisfy the demands of quantitative analysis. Quantitative analysis was performed by establishing a GC-MS internal standard curve. The analysis results showed that the correlation coefficients were greater than 0.999 0,the limits of detection (LOD) were 0.55~13.06 μg/kg and the limits of quantitation (LOQ) were 1.85~43.55 μg/kg. It showed that the method has high sensitivity. The results of sample determination and recovery experiment showed that the average added standard recovery of the neutral aromatic components from cigarette mainstream smoke was in the range of 64.39%~93.57% and the relative standard deviations were less than 10%. It showed that the method could satisfy the requirement of quantitative analysis of trace compounds, with good reproducibility.
A high efficient cembratriene-4,6-diol degradation strain YI1-3 was isolated from tobacco leaf with spread plate and streak plate methods. The cembratriene-4,6-diol was the only carbon source, and the major degradation products were farnesal (8.57%). This strain YI1-3 was identified preliminarily as Novosphingobium panipatense through the analysis of classical morphology and 16S rDNA sequence of phylogenetic tree. The strain was cultured in the fementation medium containing cembratriene-4,6-diol, the degradation rate of substrates reached 74.58% after 66 h.
The development and application of natural tobacco additive with aroma-improving, moisturizing, stimulation-reducing and reducing-offensive odor functions were reviewed. It was pointed out that compared with the various research achievements of natural tobacco additive, its application needs to be further studied. In future, the focus of study should be on the following aspects:developing and optimizing tobacco additive processing during cigarette blending and clarifying its mechanism; optimizing the additive blending and clarifying its mechanism, improving tobacco purity of effective component and developing new cigarette additives by microbial fermentation technology. All these aims to improve the sensory quality of cigarette, form cigarette style in order to meet the requirements of consumer taste.
For performance analysis of permanent magnet synchronous motor (PMSM) under demagnetization falut, a simulation model of PMSM was established on the Matlab/Simulink platform based the mathematical model of PMSM. Through changing the flux linkage to simulate demagnetization fault, with PMSM magnetic chain as input parameters, the model simulated the permanent magnet demagnetization fault through changing the parameters, and set up the operation condition to simulate. The characteristics of the torque, rotational speed and stator current of the PMSM were obtained by the simulation. The simulation results showed that with the increase of the demagnetization degree, the output torque were smaller, the fluctuation of output torque and rotational speed increased, the motor starting time was extended, the stator current gradually decreased, and the system convergence performance became worse. When the degree of demagnetization reached more than 50%, the motor could not enter the stable operation state.
In order to reduce the delay in the process of traffic information dissemination, and realize a wide range of efficient dissemination of traffic information under different traffic density conditions,a vehicle collaborative sensing method based on road segmentation and data abstraction in IVO was proposed. This method divided the road into multiple equal-length sections and set a certain number of sections as a road segment cluster, and used the cooperative perception of the road segment to improve the data transmission efficiency. On this basis, the distributed self-organizing traffic system framework was constructed to improve the traditional traffic information transmission system through the array form in the database to collect traffic data. Simulation results showed that this method could realize a wide range of traffic information transmission, even in the vehicle density environment could guarantee the delay of information dissemination within a reasonable range.
Aiming at the fluctuation of the pot bottom temperature measurement value caused by factors such as flame instability, an adaptive algorithm for temperature measurement of infrared sensor was proposed.By taking weighted average of the historical temperature samples and selecting the appropriate temperature sampling frequency and adaptive system parameters, the algorithm could effectively filter the stochastic temperature drift of the single temperature sample and solve the overheating signal judgement interval increasing caused by the temperature fluctuation so as to improve the sensitivity of overheating signal.Experimental results showed that the proposed algorithm could detect the overheating signal within 5 s,and the complexity of the algorithm was reduced to O(1).
The definition of centroskew self-conjugate matrix and some matrix theories were introduced.It was proved that the transposed matrix AT,and inversion A-1(A≠0) of a centroskew self-conjugate matrix A were still centroskew self-conjugate matrix. The direct product of any two centroskew self-conjugate matrix was centroskew self-conjugate matrix. The A* of an even order centroskew self-conjugate matrix and Am of the odd number degree power were still centroskew self-conjugate matrix. When the centroskew self-conjugate matrix of A and -A had the same characteristic values, and 0≠X0=(a1,a2,…,an)T∈Cn was a characteristic vector of the characteristic value λ0 belonging to a centroskew self-conjugate matrix A∈Cn×n, VX0=(an,an-1,…,a1)T was also a characteristic vector of the characteristic value λ0 belonging to -A.
Founded in 1986, bimonthly
Administered by:The Education Department Henan Province
Sponsored by:Zhengzhou University of Light Industry
Editor-in-chief:Wei Shizhong
Executive Editor-in-Chief:Zou Lin
Deputy Editor-in-Chief:Qu Shuanghong
Edited & published by:Editorial Department of Journal of Light Industry
CN 41-1437/TS
ISSN 2096-1553
Address:136 Science Avenue, Zhengzhou City, Henan Province, China
Postal Code:450001
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