Frequent pattern mining plays an essential role in many important data mining tasks. FP-growth is a veryefficient algorithm for frequent pattern mining. However, it still suffers from creating conditional FP-tree sepa...Frequent pattern mining plays an essential role in many important data mining tasks. FP-growth is a veryefficient algorithm for frequent pattern mining. However, it still suffers from creating conditional FP-tree separatelyand recursively during the mining process. In this paper, we propose a new algorithm, called Least-Item-First Pat-tern Growth (LIFPG), for mining frequent patterns. LIFPG mines frequent patterns directly in Trans-tree withoutusing any additional data structures. The key idea is that least items are always considered first when the current pat-tern growth. By this way, conditional sub-tree can be created directly in Trans-tree by adjusting node-links and re-counting counts of some nodes. Experiments show that, in comparison with FP-Growth, our algorithm is about fourtimes faster and saves half of memory; it also has good time and space scalability with the number of transactions,and has an excellent performance in dense dataset mining as well.展开更多
Trans-4-hydroxy-2-hexenal(4-HHE) and trans-4-hydroxy-2-nonenal(4-HNE) are secondary lipid peroxidation products in edible oils, which are cytotoxic and genotoxic. They could covalently bind with protein, phospholipids...Trans-4-hydroxy-2-hexenal(4-HHE) and trans-4-hydroxy-2-nonenal(4-HNE) are secondary lipid peroxidation products in edible oils, which are cytotoxic and genotoxic. They could covalently bind with protein, phospholipids and DNA, further disrupting the normal function of liver, lung and brain.Derivation process was generally conducted during pretreatment before detection and quantification of 4-HHE and 4-HNE. However, the derivation procedures were time consuming and chemical degradation may occur during the process. Hence, this paper aims to establish a simple solid phase extractionhigh performance liquid chromatography(SPE-HPLC) method to determine the 4-HHE and 4-HNE contents in thermally treated soybean oil. C18 solid phase extraction was applied in the pretreatment process. Firstly, the reliability of the method was evaluated. Good linearity was observed in the range of 0.1–0.5 μg/m L and 0.5–10 μg/m L for 4-HHE and 4-HNE. The limit of detection(LOD) of 4-HHE and 4-HNE were 0.0486 and 0.0129 μg/m L, respectively. And the limit of quantitation(LOQ) of4-HHE and 4-HNE were 0.1458 and 0.0431 μg/m L, respectively. Recovery rate were in the range of89.11%–91.58% and 71.83%–79.40% for 4-HHE and 4-HNE, respectively. The method achieved the extraction, purification and detection of 4-HHE and 4-HNE simultaneously and had the advantages of simple operation, effectiveness, high precision, good repeatability. Then, the method was applied to monitor the concentrations of 4-HHE and 4-HNE in soybean oil heated at 180 °C for 40 h. The contents of 4-HHE and 4-HNE were 0–0.32 μg/g and 0–6.97 μg/g, respectively, which provided guidance for evaluating health risks of thermally treated soybean oil during heating.展开更多
Molecular dynamic simulation was employed to predict the melting points Tm of TNAD/HMX, TNAD/RDX, TNAD/DINA, and TNAD/DNP systems （tans-1,4,5,8- tetranitro-1,4,5,8-tetraazadacalin （TNAD）, dinitropiperazine （DNP）,...Molecular dynamic simulation was employed to predict the melting points Tm of TNAD/HMX, TNAD/RDX, TNAD/DINA, and TNAD/DNP systems （tans-1,4,5,8- tetranitro-1,4,5,8-tetraazadacalin （TNAD）, dinitropiperazine （DNP）, cyclotetramethylenetetranitroamine （HMX）, cyclotrimethylenetrinitramine （RDX）, and N-nitrodihydroxyethylaminedinitrate （DINA））. Tm was determined from the inflexion point on the curve of mean specific volume vs. temperature. The result shows that the Tm values of TNAD/HMX, TNAD/RDX, and TNAD/DINA systems are 500, 536, and 488 K, respectively. The TNAD/DNP system has no obvious Tm value, which shows the system is insoluble. Using Tm, the solubility of the four systems was analyzed. The radial distribution functions of the four systems were analyzed and the main intermolecular forces between TNAD and other energetic components are short-range interactions. The better the solubility is, the stronger the intermoleenlar interaction is. In addition, the force field energy at different temperature was also analyzed to predict Tm of the four systems.展开更多
AIM: To determine the effect of apoptosis on gastric cancer cells (SGC-7901) induced by cis-9, trans-11-conjugated linoleic acid (c9, t11-CLA) and its possible mechanism in the inhibition of cancer cells growth.METHOD...AIM: To determine the effect of apoptosis on gastric cancer cells (SGC-7901) induced by cis-9, trans-11-conjugated linoleic acid (c9, t11-CLA) and its possible mechanism in the inhibition of cancer cells growth.METHODS: Using cell culture, flow cytometery and immunocytochemical techniques, we examined the cell growth, frequency of apoptosis and distribution of cell cycle,expression of ki67, bcl-2, Fas, and c-myc of SGC-7901 cells which were treated with various c9, t11-CLA concentrations (25,50,100 and 200 μmol@L-1) of c9, t11-CLA for 24h and 48 h,with a negative control (0.1% ethanol).RESULTS: The growth of SGC-7901 cells was inhibited by c9,t11-CLA. Eight days after treatment with various concentrations of c9,t11-CLA, as mentioned above, the inhibition rates were 5.9 %, 20.2 %,75.6 % and 82.4 %, respectively. The frequency of apoptosis on SGC-7901 cells induced by different concentrations of c9, t11-CLA (except for 25 μmol@L-1, 24 h) was significantly greater than that in the negative control (P＜0.01). To further investigate the influence of the cell cycle progression, we found that apoptosis induced by c9, t11-CLA may be involved in blocking the cell cycle of SGC-7901 cells. Immunocytochemical staining demonstrated that SGC-7901 cells preincubated in media supplemented with different c9, t11-CLA concentrations for various time periods significantly decreased the expressions of ki67 (the expression rates were 18.70-3.20 %, at 24 h and 8.10-0.20 % at 48 h, respectively), bd-2 (4.30-0.15 % at 24 h and 8.05 %-0 at 48 h),and c-myc(4.85-2.20 % at 24 h and 4.75-0.30 % at 48 h) as compared with those in the controls (the expressions of ki67, bcl-2, and c-mycwere 15.1% at 24 h and 13.5 % at 48 h, 6.80 % at 24 h and 8.00 % at 48 h,5.50 % at 24 h and 5.30 % at 48 h, respectively) (P＜0.01),whereas the expressions of Fas were increased (0.60-2.75 %,24 h and 0.45-5.95 %, 48 h).CONCLUSION: The growth and proliferation of SGC-7901 cells are inhibited by cg, t11-CLA via blocking the cell cycle,pathways of bcl-2-associated mitochondria with reduced expression of bcl-2 and Fas-associated death domain protein (FADD) with enhanced expression of Fas. But expression of c-myc on SGC-7901 cells is lower than that in negative control, which needs to be studied further.展开更多
Powdered activated carbon（PAC） adsorption of two fishy odorants, trans,trans-2,4-heptadienal（HDE） and trans,trans-2,4-decadienal（DDE）, was investigated. Both the pseudo first-order and the pseudo second-order ki...Powdered activated carbon（PAC） adsorption of two fishy odorants, trans,trans-2,4-heptadienal（HDE） and trans,trans-2,4-decadienal（DDE）, was investigated. Both the pseudo first-order and the pseudo second-order kinetic models well described the kinetics curves, and DDE was more readily removed by PAC. In isotherm tests, both Freundlich and Modified Freundlich isotherms fitted the experimental data well. PAC exhibited a higher adsorption capacity for DDE than for HDE, which could be ascribed to the difference in their hydrophobicity. The calculated thermodynamic parameters（ΔG^0, ΔH^0, and ΔS^0） indicated an exothermic and spontaneous adsorption process. PAC dosage, p H, and natural organic matter（NOM） presence were found to influence the adsorption process. With increasing PAC dosage, the pseudo first-order and pseudo second-order rate constants both increased. The value of p H had little influence on HDE or DDE molecules but altered the surface charge of PAC, and the maximum adsorption capacity occurred at p H 9. The presence of NOM, especially the fraction with molecular weight less than1 k Dalton, hindered the adsorption. The study showed that preloaded NOM impaired the adsorption capacity of HDE or DDE more severely than simultaneously fed NOM did.展开更多
Abstract Two series of trans-1,4-poly（butadiene-co-isoprene） copolymers （TBIR） were prepared using the catalyst system TiCl4/MgCl2-Al（i-Bu）3 at different reaction temperatures. All dyad and triads sequence distr...Abstract Two series of trans-1,4-poly（butadiene-co-isoprene） copolymers （TBIR） were prepared using the catalyst system TiCl4/MgCl2-Al（i-Bu）3 at different reaction temperatures. All dyad and triads sequence distributions, the number-average sequence length and the sequence concentration of the copolymers were calculated according to 13C-NMR spectra. The influences of temperature and initial molar ratio of butadiene to isoprene （Bd to Ip） on the distribution of the chain segments in the TBIR copolymers were discussed. The correlation of copolymer compositions and thermal properties were also evaluated, which facilitated the understanding of controlling the degree of crystallinity and the transition tempera^re by changing Bd content and temperature.展开更多
A series of trans-1,4-butadiene/isoprene copolymers were prepared using the catalyst system TiCl4/MgCl2-Al（i- Bu）3 with bulk precipitation technology at different temperatures. Monomers reactivity ratios were calcul...A series of trans-1,4-butadiene/isoprene copolymers were prepared using the catalyst system TiCl4/MgCl2-Al（i- Bu）3 with bulk precipitation technology at different temperatures. Monomers reactivity ratios were calculated based on the Kelen-Tiid6s （K-T） method and the Mao-Huglin （M-H） method. The influence of temperature on copolymer composition and polymerization rate was discussed in detail. The increase of reaction temperature brought the decrease of butadiene reactivity ratio rBd and supplied an effective adjustment on copolymers＇ composition distribution.展开更多
The molecular weight of a polymer is of prime importance and greatly influences the processing and mechanical properties of the polymer. Trans-1,4-poly(butadiene-co-isoprene) multi-block copolymer rubbers(TBIR) exhibi...The molecular weight of a polymer is of prime importance and greatly influences the processing and mechanical properties of the polymer. Trans-1,4-poly(butadiene-co-isoprene) multi-block copolymer rubbers(TBIR) exhibit outstanding fatigue resistance, low heat build-up and good abrasion resistance, and are expected to be desirable candidate for high performance tire. Study on the influence of TBIR with different molecular weights on the structure and properties of TBIR and natural rubber(NR)/TBIR blends is essential to understand its contribution to the greatly improved dynamic properties of the rubber vulcanizates. TBIR with different molecular weights characterized by 1H-NMR, 13C-NMR, GPC, and DSC were highly trans-1,4-copolymers with similar chain sequence distribution and crystalline trans-1,4-polyisoprene(TPI) blocks. The green strength and modulus of TBIR increased with the increasing molecular weight.The NR/TBIR compounds filled with 40 phr carbon black were chemically cured by sulfur for the preparation of NR/TBIR vulcanizates.The compatibility between NR and TBIR, filler distribution, crosslinking bond and density, and properties of NR/TBIR vulcanizates were studied. The NR/TBIR vulcanizates showed increasing tensile strength, hardness, modulus, rebound, abrasion resistance, and flexural fatigue properties with increasing molecular weight of TBIR. Furthermore, they presented significant improvement in flexural fatigue resistance when compared with that of NR vulcanizate. The contribution mechanism of TBIR on the NR/TBIR blends was discussed. The TBIR with a wide range of molecular weight are ideal rubbers for high performance tires.展开更多
Background:Starch is an important substance that supplies energy to ruminants.To provide sufficient energy for high-yielding dairy ruminants,they are typically fed starch-enriched diets.However,starch-enriched diets h...Background:Starch is an important substance that supplies energy to ruminants.To provide sufficient energy for high-yielding dairy ruminants,they are typically fed starch-enriched diets.However,starch-enriched diets have been proven to increase the risk of milk fat depression(MFD)in dairy cows.The starch present in ruminant diets could be divided into rumen-degradable starch(RDS)and rumen escaped starch(RES)according to their different degradation sites(rumen or intestine).Goats and cows have different sensitivities to MFD.Data regarding the potential roles of RDS in milk fat synthesis in the mammary tissue of dairy goats and in regulating the occurrence of MFD are limited.Results:Eighteen Guanzhong dairy goats(day in milk=185±12 d)with similar parity,weight,and milk yield were selected and randomly assigned to one of three groups(n=6),which were fed an LRDS diet(Low RDS=20.52%),MRDS diet(Medium RDS=22.15%),or HRDS diet(High RDS=24.88%)for 5 weeks.Compared with that of the LRDS group,the milk fat contents in the MRDS and HRDS groups significantly decreased.The yields of short-,mediumand long-chain fatty acids decreased in the HRDS group.Furthermore,increased RDS significantly decreased ruminal B.fibrisolvens and Pseudobutyrivibrio abundances and increased the trans-10,cis-12 conjugated linoleic acid(CLA)and trans-10 C18:1 contents in the rumen fluid.A multiomics study revealed that the HRDS diet affected mammary lipid metabolism down-regulation of ACSS2,MVD,AGPS,SCD5,FADS2,CERCAM,SC5D,HSD17B7,HSD17B12,ATM,TP53RK,GDF1 and LOC102177400.Remarkably,the significant decrease of INSIG1,whose expression was depressed by trans-10,cis-12 CLA,could reduce the activity of SREBP and,consequently,downregulate the downstream gene expression of SREBF1.Conclusions:HRDS-induced goat MFD resulted from the downregulation of genes involved in lipogenesis,particularly,INSIG1.Specifically,even though the total starch content and the concentrate-to-fiber ratio were the same as those of the high-RDS diet,the low and medium RDS diets did not cause MFD in lactating goats.展开更多
The solubility of trans-1,2-cyclohexanediol in water, methyl acetate, acetic ester, propyl acetate, butyl acetate, methyl acrylate, ethyl acrylate, 2-pentanone and acetoacetic ester was measured at temperatures rangin...The solubility of trans-1,2-cyclohexanediol in water, methyl acetate, acetic ester, propyl acetate, butyl acetate, methyl acrylate, ethyl acrylate, 2-pentanone and acetoacetic ester was measured at temperatures ranging from about 300 K to 330 K, using a modification of the experimental technique of laser monitoring observation system. The solubilities were calculated by λh method, in which new parameters were introduced to express the activity coefficients of trans-1,2-cyclohexanediol, and determined from the experimental data. The new parameters provide good calculated results. The experimental data were also correlated with a simple model, and results were compared with present λh model.展开更多
Using a laser observation technique,the solubilities of trans-1,2-cyclohexanediol in butyl acetate+wa- ter were measured at the temperature range from 298.15K to 323.15K by a synthetic method at atmospheric pres- sure...Using a laser observation technique,the solubilities of trans-1,2-cyclohexanediol in butyl acetate+wa- ter were measured at the temperature range from 298.15K to 323.15K by a synthetic method at atmospheric pres- sure.It is shown that the solubilities of trans-1,2-cyclohexanediol in butyl acetate+water were affected greatly by the proportion of butyl acetate and water,and presented maximum value at given temperature.The UNIFAC model was used to correlate the experimental data.The average relative deviation(ARD)between experimental and calculated values is 3.03%.展开更多
文摘Frequent pattern mining plays an essential role in many important data mining tasks. FP-growth is a veryefficient algorithm for frequent pattern mining. However, it still suffers from creating conditional FP-tree separatelyand recursively during the mining process. In this paper, we propose a new algorithm, called Least-Item-First Pat-tern Growth (LIFPG), for mining frequent patterns. LIFPG mines frequent patterns directly in Trans-tree withoutusing any additional data structures. The key idea is that least items are always considered first when the current pat-tern growth. By this way, conditional sub-tree can be created directly in Trans-tree by adjusting node-links and re-counting counts of some nodes. Experiments show that, in comparison with FP-Growth, our algorithm is about fourtimes faster and saves half of memory; it also has good time and space scalability with the number of transactions,and has an excellent performance in dense dataset mining as well.
基金supported by grants from the National Natural Science Foundation of China(No.31471668)。
文摘Trans-4-hydroxy-2-hexenal(4-HHE) and trans-4-hydroxy-2-nonenal(4-HNE) are secondary lipid peroxidation products in edible oils, which are cytotoxic and genotoxic. They could covalently bind with protein, phospholipids and DNA, further disrupting the normal function of liver, lung and brain.Derivation process was generally conducted during pretreatment before detection and quantification of 4-HHE and 4-HNE. However, the derivation procedures were time consuming and chemical degradation may occur during the process. Hence, this paper aims to establish a simple solid phase extractionhigh performance liquid chromatography(SPE-HPLC) method to determine the 4-HHE and 4-HNE contents in thermally treated soybean oil. C18 solid phase extraction was applied in the pretreatment process. Firstly, the reliability of the method was evaluated. Good linearity was observed in the range of 0.1–0.5 μg/m L and 0.5–10 μg/m L for 4-HHE and 4-HNE. The limit of detection(LOD) of 4-HHE and 4-HNE were 0.0486 and 0.0129 μg/m L, respectively. And the limit of quantitation(LOQ) of4-HHE and 4-HNE were 0.1458 and 0.0431 μg/m L, respectively. Recovery rate were in the range of89.11%–91.58% and 71.83%–79.40% for 4-HHE and 4-HNE, respectively. The method achieved the extraction, purification and detection of 4-HHE and 4-HNE simultaneously and had the advantages of simple operation, effectiveness, high precision, good repeatability. Then, the method was applied to monitor the concentrations of 4-HHE and 4-HNE in soybean oil heated at 180 °C for 40 h. The contents of 4-HHE and 4-HNE were 0–0.32 μg/g and 0–6.97 μg/g, respectively, which provided guidance for evaluating health risks of thermally treated soybean oil during heating.
基金V. ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.U1304111）, the Laboratory of Science and Technology on Combustion and Explosion （No.9140C3501021101）, China Postdoctoral Science Foundation （No.2013M531361）, and Jiangsu Planned Projects for Postdoctoral Research Funds （No.1201015B）.
文摘Molecular dynamic simulation was employed to predict the melting points Tm of TNAD/HMX, TNAD/RDX, TNAD/DINA, and TNAD/DNP systems （tans-1,4,5,8- tetranitro-1,4,5,8-tetraazadacalin （TNAD）, dinitropiperazine （DNP）, cyclotetramethylenetetranitroamine （HMX）, cyclotrimethylenetrinitramine （RDX）, and N-nitrodihydroxyethylaminedinitrate （DINA））. Tm was determined from the inflexion point on the curve of mean specific volume vs. temperature. The result shows that the Tm values of TNAD/HMX, TNAD/RDX, and TNAD/DINA systems are 500, 536, and 488 K, respectively. The TNAD/DNP system has no obvious Tm value, which shows the system is insoluble. Using Tm, the solubility of the four systems was analyzed. The radial distribution functions of the four systems were analyzed and the main intermolecular forces between TNAD and other energetic components are short-range interactions. The better the solubility is, the stronger the intermoleenlar interaction is. In addition, the force field energy at different temperature was also analyzed to predict Tm of the four systems.
基金the National Natural Science Foundation of China,No.39870661
文摘AIM: To determine the effect of apoptosis on gastric cancer cells (SGC-7901) induced by cis-9, trans-11-conjugated linoleic acid (c9, t11-CLA) and its possible mechanism in the inhibition of cancer cells growth.METHODS: Using cell culture, flow cytometery and immunocytochemical techniques, we examined the cell growth, frequency of apoptosis and distribution of cell cycle,expression of ki67, bcl-2, Fas, and c-myc of SGC-7901 cells which were treated with various c9, t11-CLA concentrations (25,50,100 and 200 μmol@L-1) of c9, t11-CLA for 24h and 48 h,with a negative control (0.1% ethanol).RESULTS: The growth of SGC-7901 cells was inhibited by c9,t11-CLA. Eight days after treatment with various concentrations of c9,t11-CLA, as mentioned above, the inhibition rates were 5.9 %, 20.2 %,75.6 % and 82.4 %, respectively. The frequency of apoptosis on SGC-7901 cells induced by different concentrations of c9, t11-CLA (except for 25 μmol@L-1, 24 h) was significantly greater than that in the negative control (P＜0.01). To further investigate the influence of the cell cycle progression, we found that apoptosis induced by c9, t11-CLA may be involved in blocking the cell cycle of SGC-7901 cells. Immunocytochemical staining demonstrated that SGC-7901 cells preincubated in media supplemented with different c9, t11-CLA concentrations for various time periods significantly decreased the expressions of ki67 (the expression rates were 18.70-3.20 %, at 24 h and 8.10-0.20 % at 48 h, respectively), bd-2 (4.30-0.15 % at 24 h and 8.05 %-0 at 48 h),and c-myc(4.85-2.20 % at 24 h and 4.75-0.30 % at 48 h) as compared with those in the controls (the expressions of ki67, bcl-2, and c-mycwere 15.1% at 24 h and 13.5 % at 48 h, 6.80 % at 24 h and 8.00 % at 48 h,5.50 % at 24 h and 5.30 % at 48 h, respectively) (P＜0.01),whereas the expressions of Fas were increased (0.60-2.75 %,24 h and 0.45-5.95 %, 48 h).CONCLUSION: The growth and proliferation of SGC-7901 cells are inhibited by cg, t11-CLA via blocking the cell cycle,pathways of bcl-2-associated mitochondria with reduced expression of bcl-2 and Fas-associated death domain protein (FADD) with enhanced expression of Fas. But expression of c-myc on SGC-7901 cells is lower than that in negative control, which needs to be studied further.
基金supported by the National Natural Science Foundation of China (No. 51290284)
文摘Powdered activated carbon（PAC） adsorption of two fishy odorants, trans,trans-2,4-heptadienal（HDE） and trans,trans-2,4-decadienal（DDE）, was investigated. Both the pseudo first-order and the pseudo second-order kinetic models well described the kinetics curves, and DDE was more readily removed by PAC. In isotherm tests, both Freundlich and Modified Freundlich isotherms fitted the experimental data well. PAC exhibited a higher adsorption capacity for DDE than for HDE, which could be ascribed to the difference in their hydrophobicity. The calculated thermodynamic parameters（ΔG^0, ΔH^0, and ΔS^0） indicated an exothermic and spontaneous adsorption process. PAC dosage, p H, and natural organic matter（NOM） presence were found to influence the adsorption process. With increasing PAC dosage, the pseudo first-order and pseudo second-order rate constants both increased. The value of p H had little influence on HDE or DDE molecules but altered the surface charge of PAC, and the maximum adsorption capacity occurred at p H 9. The presence of NOM, especially the fraction with molecular weight less than1 k Dalton, hindered the adsorption. The study showed that preloaded NOM impaired the adsorption capacity of HDE or DDE more severely than simultaneously fed NOM did.
基金financially supported by the National Basic Research Program of China(No.2015CB654700(2015CB654706))Shandong Province Natural Science Fund for Distinguished Young Scholars(No.JQ201213)the National Natural Science Foundation of China(No.51473083)
文摘Abstract Two series of trans-1,4-poly（butadiene-co-isoprene） copolymers （TBIR） were prepared using the catalyst system TiCl4/MgCl2-Al（i-Bu）3 at different reaction temperatures. All dyad and triads sequence distributions, the number-average sequence length and the sequence concentration of the copolymers were calculated according to 13C-NMR spectra. The influences of temperature and initial molar ratio of butadiene to isoprene （Bd to Ip） on the distribution of the chain segments in the TBIR copolymers were discussed. The correlation of copolymer compositions and thermal properties were also evaluated, which facilitated the understanding of controlling the degree of crystallinity and the transition tempera^re by changing Bd content and temperature.
基金financially supported by the National Key Technology R&D Program of China(No.2011BAE26B05)the Shandong Province Natural Science Fund for Distinguished Young Scholars(No.JQ201213)+2 种基金National Natural Science Foundation of China(No.21174074)Shandong Province Science and Technology Development Plan(No.2012GGA05042)the Major Projects of Independent Innovation Achievements Transformation in Shandong Province(No.2013ZHZX1A0207)
文摘A series of trans-1,4-butadiene/isoprene copolymers were prepared using the catalyst system TiCl4/MgCl2-Al（i- Bu）3 with bulk precipitation technology at different temperatures. Monomers reactivity ratios were calculated based on the Kelen-Tiid6s （K-T） method and the Mao-Huglin （M-H） method. The influence of temperature on copolymer composition and polymerization rate was discussed in detail. The increase of reaction temperature brought the decrease of butadiene reactivity ratio rBd and supplied an effective adjustment on copolymers＇ composition distribution.
基金financially supported by the National Basic Research Program of China(No.2015CB654700(2015CB 654706))Major Program of Shandong Province Natural Science Foundation(No.ZR2017ZA0304)Taishan Scholar Program
文摘The molecular weight of a polymer is of prime importance and greatly influences the processing and mechanical properties of the polymer. Trans-1,4-poly(butadiene-co-isoprene) multi-block copolymer rubbers(TBIR) exhibit outstanding fatigue resistance, low heat build-up and good abrasion resistance, and are expected to be desirable candidate for high performance tire. Study on the influence of TBIR with different molecular weights on the structure and properties of TBIR and natural rubber(NR)/TBIR blends is essential to understand its contribution to the greatly improved dynamic properties of the rubber vulcanizates. TBIR with different molecular weights characterized by 1H-NMR, 13C-NMR, GPC, and DSC were highly trans-1,4-copolymers with similar chain sequence distribution and crystalline trans-1,4-polyisoprene(TPI) blocks. The green strength and modulus of TBIR increased with the increasing molecular weight.The NR/TBIR compounds filled with 40 phr carbon black were chemically cured by sulfur for the preparation of NR/TBIR vulcanizates.The compatibility between NR and TBIR, filler distribution, crosslinking bond and density, and properties of NR/TBIR vulcanizates were studied. The NR/TBIR vulcanizates showed increasing tensile strength, hardness, modulus, rebound, abrasion resistance, and flexural fatigue properties with increasing molecular weight of TBIR. Furthermore, they presented significant improvement in flexural fatigue resistance when compared with that of NR vulcanizate. The contribution mechanism of TBIR on the NR/TBIR blends was discussed. The TBIR with a wide range of molecular weight are ideal rubbers for high performance tires.
基金This research was financially supported by the National Key Research and Development Program of China(award number:2017YFD0500500)the Science&Technological Project of Shaanxi Province,China(award number:2017 TSCXL-NY-04-01).
文摘Background:Starch is an important substance that supplies energy to ruminants.To provide sufficient energy for high-yielding dairy ruminants,they are typically fed starch-enriched diets.However,starch-enriched diets have been proven to increase the risk of milk fat depression(MFD)in dairy cows.The starch present in ruminant diets could be divided into rumen-degradable starch(RDS)and rumen escaped starch(RES)according to their different degradation sites(rumen or intestine).Goats and cows have different sensitivities to MFD.Data regarding the potential roles of RDS in milk fat synthesis in the mammary tissue of dairy goats and in regulating the occurrence of MFD are limited.Results:Eighteen Guanzhong dairy goats(day in milk=185±12 d)with similar parity,weight,and milk yield were selected and randomly assigned to one of three groups(n=6),which were fed an LRDS diet(Low RDS=20.52%),MRDS diet(Medium RDS=22.15%),or HRDS diet(High RDS=24.88%)for 5 weeks.Compared with that of the LRDS group,the milk fat contents in the MRDS and HRDS groups significantly decreased.The yields of short-,mediumand long-chain fatty acids decreased in the HRDS group.Furthermore,increased RDS significantly decreased ruminal B.fibrisolvens and Pseudobutyrivibrio abundances and increased the trans-10,cis-12 conjugated linoleic acid(CLA)and trans-10 C18:1 contents in the rumen fluid.A multiomics study revealed that the HRDS diet affected mammary lipid metabolism down-regulation of ACSS2,MVD,AGPS,SCD5,FADS2,CERCAM,SC5D,HSD17B7,HSD17B12,ATM,TP53RK,GDF1 and LOC102177400.Remarkably,the significant decrease of INSIG1,whose expression was depressed by trans-10,cis-12 CLA,could reduce the activity of SREBP and,consequently,downregulate the downstream gene expression of SREBF1.Conclusions:HRDS-induced goat MFD resulted from the downregulation of genes involved in lipogenesis,particularly,INSIG1.Specifically,even though the total starch content and the concentrate-to-fiber ratio were the same as those of the high-RDS diet,the low and medium RDS diets did not cause MFD in lactating goats.
基金Supported by the Natural Science Foundation of Henan Province (No. 0211020800)
文摘The solubility of trans-1,2-cyclohexanediol in water, methyl acetate, acetic ester, propyl acetate, butyl acetate, methyl acrylate, ethyl acrylate, 2-pentanone and acetoacetic ester was measured at temperatures ranging from about 300 K to 330 K, using a modification of the experimental technique of laser monitoring observation system. The solubilities were calculated by λh method, in which new parameters were introduced to express the activity coefficients of trans-1,2-cyclohexanediol, and determined from the experimental data. The new parameters provide good calculated results. The experimental data were also correlated with a simple model, and results were compared with present λh model.
基金Supported by the Natural Science Foundation of Henan Province （No.0211020800）.
文摘Using a laser observation technique,the solubilities of trans-1,2-cyclohexanediol in butyl acetate+wa- ter were measured at the temperature range from 298.15K to 323.15K by a synthetic method at atmospheric pres- sure.It is shown that the solubilities of trans-1,2-cyclohexanediol in butyl acetate+water were affected greatly by the proportion of butyl acetate and water,and presented maximum value at given temperature.The UNIFAC model was used to correlate the experimental data.The average relative deviation(ARD)between experimental and calculated values is 3.03%.
