Kinetics of microbial hydrogenation of free linoleic acid to conjugated linoleic acids

Xu, H.,Lee, H.Y.,Hwang, B.,Nam, J.H.,Kang, H.Y.,Ahn, J. Blackwell Publishing Ltd 2008 Journal of applied microbiology Vol.105 No.6

<P>Abstract</P><P>Aims: </P><P>To investigate the ability of selected probiotic bacterial strains to produce conjugated linoleic acid (CLA) and also to estimate the biohydrogenation kinetics of <I>Lactobacillus acidophilus</I> on the production of CLA from free linoleic acid (LA).</P><P>Methods and Results: </P><P>Six probiotic bacteria, <I>Lact</I>. <I>paracasei</I>, <I>Lact</I>. <I>rhamnosus</I> GG, <I>Lact</I>. <I>acidophilus</I> ADH, and <I>Bifidobacterium longum</I> B6, <I>Lact</I>. <I>brevis</I>, and <I>Lact</I>. <I>casei</I>, were used to examine their ability to convert LA to CLA. LA tolerance was evaluated by addition of different LA concentrations in MRS broth. <I>Lact</I>. <I>acidophilus</I> showed the major tolerant to LA and the greatest CLA-producing ability (36–48 &mgr;g ml<SUP>−1</SUP> of CLA). The rate-controlling steps were <I>k</I><SUB>2</SUB> and <I>k</I><SUB>1</SUB> for the addition of 1 and 3 mg ml<SUP>−1</SUP> of LA, respectively. The percentage of CLA conversion was higher in MRS broth supplemented with 1 mg ml<SUP>−1</SUP> (65%) than 3 mg ml<SUP>−1</SUP> (26%).</P><P>Conclusion: </P><P>The results provide useful information and new approach for understanding the biohydrogenation mechanisms of CLA production.</P><P>Significance and Impact of the Study: </P><P>This study would help elucidate the pathway from LA to stearic acid (SA), known as biohydrogenation. In addition, the use of selected probiotic bacteria might lead to a significant improvement in food safety.</P>

Investigation of PCR-RFLPs within Major Histocompatibility Complex B-G Genes Using Two Restriction Enzymes in Eight Breeds of Chinese Indigenous Chickens

R. F. Xu,K. Li,G. H. Chen,B. Y. Z. Qiang,D. L. Mo,B. Fan,C. C. Li,M. Yu,M. J. Zhu,T. A. Xiong,B. Liu 아세아·태평양축산학회 2005 Animal Bioscience Vol.18 No.7

New polymorphism of major histocompatibility complex B-G genes was investigated by amplification and digestion of a 401bp fragment including intron 1 and exon 2 using polymerase chain reaction-restriction fragment length polymorphism (PCRRFLP) technique with two restriction enzymes of Msp I and Tas I in eight breeds of Chinese indigenous chickens and one exotic breed. In the fragment region of the gene, three novel single nucleotide polymorphisms (SNPs) were detected at the two restriction sites. We found the transition of two nucleotides of A294G and T295C occurred at Tas I restriction site, and consequently led to a nonsynonymous substitution of asparagine into serine at position 54 within the deduced amino acid sequence of immunoglobulin variableregion- like domain encoded by the exon 2 of B-G gene. It was observed at rare frequency that a single mutation of A294G occurring at the site, also caused an identical substitution of amino acid, asparagine 54-to-serine, to that we described previously. And the transversion of G319C at Msp I site led to a non-synonymous substitution, glutamine 62-to-histidine. The new alleles and allele frequencies identified by the PCR-RFLP method with the two enzymes were characterized, of which the allele A and B frequencies at Msp I and Tas I loci were given disequilibrium distribution either in the eight Chinese local breeds or in the exotic breed. By comparison, allele A at Msp I locus tended to be dominant, while, the allele B at Tas I locus tended to be dominant in all of the breeds analyzed. In Tibetan chickens, the preliminary association analysis revealed that no significant difference was observed between the different genotypes identified at the Msp I and Tas I loci and the laying performance traits, respectively.

The Kinetics of Anodic Dissolution and Repassivation on 316L Stainless Steel in Borate Buffer Solution Studied by Abrading Electrode Technique

( H S Xu1 ),( D B Sun ),( H Y Yu ),( H M Meng ) 한국부식방식학회(구 한국부식학회) 2015 Corrosion Science and Technology Vol.14 No.6

The capacity of passive metal to repassivate after film damage determines the development of local corrosion and the resistance to corrosion failures. In this work, the repassivation kinetics of 316L stainless steel (316LSS) was investigated in borate buffer solution (pH 9. 1) using a novel abrading electrode technique. The repassivation kinetics was analyzed in terms of the current density flowing from freshly bare 316L SS surface as measured by a potentiostatic method. During the early phase of decay (t < 2 s), according to the Avrami kinetics-based film growth model, the transient current was separated into anodic dissolution (idiss) and film formation (ifilm) components and analyzed individually. The film reformation rate and thickness were compared according to applied potential. Anodic dissolution initially dominated the repassivation for a short time, and the amount of dissolution increased with increasing applied potential in the passive region. Film growth at higher potentials occurred more rapidly compared to at lower potentials. Increasing the applied potential from 0 VSCE to 0. 8 VSCE resulted in a thicker passive film (0. 12 to 0. 52 nm). If the oxide monolayer covered the entire bare surface (θ=1), the electric field strength through the thin passive film reached 1. 6 × 107 V/cm.

FUEL PROPERTIES AND EMISSIONS CHARACTERISTICS OF ETHANOL-DIESEL BLEND ON SMALL DIESEL ENGINE

Xu, B.Y.,Qi, Y.L.,Zhang, W.B.,Cai, S.L. The Korean Society of Automotive Engineers 2007 International journal of automotive technology Vol.8 No.1

Phase separation and low cetane number are the main barriers to the large-scale use of ethanol-diesel blend fuel on small diesel engines. In this paper, an additive package is designed on the basis of the blended fuel properties to overcome these limitations. The experiments show that the solubility of ethanol in diesel is evidently increased by adding $1{\sim}2%$ (in volume) of the additive package and the flammability of ethanol-diesel blend fuel with the additive has reached the neat diesel level under the cold start conditions. Effects of the ethanol content in diesel on fuel economy, combustion characteristics, and emission characteristics are also investigated with the ethanol blend ratios of 10%, 20% and 30%. The increase in ethanol content shows that the specific fuel consumption and the brake thermal efficiency are both gradually increased compared to neat diesel. The soot concentrations of the three blended fuels are all greatly lower than that of neat diesel. $NO_x$ emission is increased with an increase in the engine load and is reduced with the increase in the ethanol blend ratio under a high load.

NUMERICAL ANALYSIS OF FUEL INJECTION IN INTAKE MANIFOLD AND INTAKE PROCESS OF A MPI NATURAL GAS ENGINE

B. Y. XU,F. Y. LIANG,S. L. CAI,Y. L. QI 한국자동차공학회 2005 International journal of automotive technology Vol.6 No.6

Unsteady state free natural gas jets injected from several types of injectors were numerically simulated. Simulations showed good agreements with the schlieren experimental results. Moreover, injections of natural gas in intake manifolds of a single-valve engine and a double-valve engine were predicted as well. Predictions revealed that large volumetric injections of natural gas in intake manifolds led to strong impingement of natural gas with the intake valves, which as a result, gave rise to pronounced backward reflection of natural gas towards the inlets of intake manifolds, together with significant increase in pressure in intake manifold. Based on our simulations, we speculated that for engines with short intake manifolds, reflections of the mixture of natural gas and air were likely to approach the inlets of intake manifolds and subsequently be inbreathed into other cylinders, resulting in non-uniform mixture distributions between the cylinders. For engines with long intake manifolds, inasmuch as the degrees of intake interferences between the cylinders were not identical in light of the ignition sequences, non-uniform intake charge distributions between the cylinders would occur.

NUMERICAL ANALYSIS OF FUEL INJECTION IN INTAKE MANIFOLD AND INTAKE PROCESS OF A MPI NATURAL GAS ENGINE

XU B. Y.,LIANG F. Y.,CAI S. L.,QI Y. L. The Korean Society of Automotive Engineers 2005 International journal of automotive technology Vol.6 No.6

Unsteady state free natural gas jets injected from several types of injectors were numerically simulated. Simulations showed good agreements with the schlieren experimental results. Moreover, injections of natural gas in intake manifolds of a single-valve engine and a double-valve engine were predicted as well. Predictions revealed that large volumetric injections of natural gas in intake manifolds led to strong impingement of natural gas with the intake valves, which as a result, gave rise to pronounced backward reflection of natural gas towards the inlets of intake manifolds, together with significant increase in pressure in intake manifold. Based on our simulations, we speculated that for engines with short intake manifolds, reflections of the mixture of natural gas and air were likely to approach the inlets of intake manifolds and subsequently be inbreathed into other cylinders, resulting in non-uniform mixture distributions between the cylinders. For engines with long intake manifolds, inasmuch as the degrees of intake interferences between the cylinders were not identical in light of the ignition sequences, non-uniform intake charge distributions between the cylinders would occur.

Understanding of the capacity contribution of carbon in phosphorus-carbon composites for high-performance anodes in lithium ion batteries

Xu, J.,Jeon, I. Y.,Ma, J.,Dou, Y.,Kim, S. J.,Seo, J. M.,Liu, H.,Dou, S.,Baek, J. B.,Dai, L. Springer Science + Business Media 2017 Nano research Vol.10 No.4

<P>Phosphorus has recently received extensive attention as a promising anode for lithium ion batteries (LIBs) due to its high theoretical capacity of 2,596 mAh.g(-1). To develop high-performance phosphorus anodes for LIBs, carbon materials have been hybridized with phosphorus (P-C) to improve dispersion and conductivity. However, the specific capacity, rate capability, and cycling stability of P-C anodes are still less than satisfactory for practical applications. Furthermore, the exact effects of the carbon support on the electrochemical performance of the P-C anodes are not fully understood. Herein, a series of xP-yC anode materials for LIBs were prepared by a simple and efficient ball-milling method. 6P-4C and 3P-7C were found to be optimum mass ratios of x/ y, and delivered initial discharge capacities of 1,803.5 and 1,585.3.mAh.g(-1), respectively, at 0.1 C in the voltage range 0.02-2 V, with an initial capacity retention of 68.3% over 200 cycles (more than 4 months cycling life) and 40.8% over 450 cycles. The excellent electrochemical performance of the 6P-4C and 3P-7C samples was attributed to a synergistic effect from both the adsorbed P and carbon.</P>

NUMERICAL ANALYSIS OF HOMOGENEOUS MIXTURE FORMATION FOR A DIRECT INJECTION LIQUID LPG ENGINE

B. Y. XU,X. C. ZHANG,J. XU,Y. L. QI,S. L. CAI 한국자동차공학회 2013 International journal of automotive technology Vol.14 No.6

A method to form a homogeneous mixture using low pressure direct injection of liquid phase LPG, pent-roof combustion chamber, flat-top piston and center-located injector layout is presented. To validate the method, the mixture formation processes in the cylinder were investigated using the CFD code. The effect of different injection timing and engine loads on the mixture formation processes were researched. The simulated results showed that, the intake tumble for high load conditions or the inclined intake swirl for part load conditions would break into small-scale vortex (turbulence) near the end of compression stroke, which enhanced the homogeneous mixture formation. The results also showed that if the liquid phase LPG was injected at 60-80oCA ATDC in intake stroke even at different loads, the homogeneous mixture would be formed under any engine load conditions.

FUEL PROPERTIES AND EMISSIONS CHARACTERISTICS OF ETHANOL-DIESEL BLEND ON SMALL DIESEL ENGINE

B. Y. XU,Y. L. QI,W. B. ZHANG,S. L. CAI 한국자동차공학회 2007 International journal of automotive technology Vol.8 No.1

Phase separation and low cetane number are the main barriers to the large-scale use of ethanol-diesel blend fuel on small diesel engines. In this paper, an additive package is designed on the basis of the blended fuel properties to overcome these limitations. The experiments show that the solubility of ethanol in diesel is evidently increased by adding 1~2% (in volume) of the additive package and the flammability of ethanol-diesel blend fuel with the additive has reached the neat diesel level under the cold start conditions. Effects of the ethanol content in diesel on fuel economy, combustion characteristics, and emission characteristics are also investigated with the ethanol blend ratios of 10%, 20% and 30%. The increase in ethanol content shows that the specific fuel consumption and the brake thermal efficiency are both gradually increased compared to neat diesel. The soot concentrations of the three blended fuels are all greatly lower than that of neat diesel. NOx emission is increased with an increase in the engine load and is reduced with the increase in the ethanol blend ratio under a high load.

Microwave Absorption and Magnetic Properties of Cobalt Ferrites/Carbon Nanotubes Nanocomposites

B. B. Zhang,P. F. Wang,J. C. Xu,Y. B. Han,H. X. Jin,D. F. Jin,X. L. Peng,B. Hong,J. Li,J. Gong,H. L. Ge,Z. W. Zhu,X. Q. Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.5

Owing to the unique microstructure and the excellent dielectric properties, carbon nanotubes(CNTs) were decorated with CoFe2O4 nanoparticles to synthesize the CoFe2O4/CNTs nanocomposites by the solvothermal method. The phase structure, morphology, magnetic properties and microwave absorption performance of the as-prepared CoFe2O4/CNTs were characterized and discussed by X-ray diffraction (XRD), thermal gravity analysis (TGA), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and vector network analyzer (VNA). All results indicated that the diameter of CoFe2O4 nanoparticles decorating on the surface of CNTs increased with the solvothermal temperature. CoFe2O4/CNTs prepared at 180℃, 200℃ and 220℃ exhibited superparamagnetism, while the other samples presented ferromagnetism at room temperature. And with the increasing solvothermal temperature, the saturation magnetization and coercivity increased up to 72 emu/g and 2000 Oe for the sample prepared at 260℃ (S-26). And the reflection loss of CoFe2O4/CNTs nanocomposites increased with the solvothermal temperature up to -15.7 dB for S-26 with the bandwidth of 2.5 GHz.