S2O2-8/ZrO2-SiO2催化合成乳酸正丁酯

对以S2O2－8/ZrO2-SiO2为催化剂催化合成乳酸正丁酯的方法进行了研究,得出其最佳工艺条件为：催化剂原料配比n(Zr)∶n(Si)=1∶15,醇酸物质的量的比为4.5∶1,催化剂用量1.0 g,乳酸用量为0.083 mol的情况下,反应时间为3.0 h,酯化率可达97.3 %。催化剂可重复使用6次以上。     

复合乳酸菌发酵蛋壳制备乳酸钙

为探索蛋壳碳酸钙发酵制备有机钙,以鸡蛋壳为原料、乳酸钙产量为评价指标,在单因素试验基础上进行Box-Behnken试验设计,优化复合乳酸菌发酵蛋壳制备乳酸钙的工艺条件。结果表明,蒙氏肠球菌、嗜热链球菌、干酪乳杆菌、保加利亚乳杆菌的最佳接种比为 1∶1∶2∶1（体积比）,最佳发酵工艺参数为温度37 ℃、发酵时间72 h、培养基初始pH 6.5、复合菌接种量8.0%。此条件下乳酸钙产量为（40.01±0.035）g/L,纯度为92.65%。傅里叶变换红外光谱、X-射线衍射的结构表征证实发酵产物为乳酸钙。研究结果将为蛋壳钙高效生物转化成乳酸钙提供可行途径与理论参考。     

Postpartum supplementation of fermented ammoniated condensed whey improved feed efficiency and plasma metabolite profile

Postpartum dietary supplementation of gluconeogenic precursors may improve the plasma metabolite profile of dairy cows, reducing metabolic disorders and improving lactation performance. The objective of this trial was to examine the effects of supplementation with fermented ammoniated condensed whey (FACW) postpartum on lactation performance and on profile of plasma metabolites and hormones in transition dairy cows. Individually fed multiparous Holstein cows were blocked by calving date and randomly assigned to control (2.9% dry matter of diet as soybean meal; n = 20) or FACW (2.9% dry matter of diet as liquid GlucoBoost, Fermented Nutrition, Luxemburg, WI; n = 19) dietary treatments. Treatments were offered from 1 to 45 d in milk (DIM). Cows were milked twice a day. Dry matter intake and milk yield were recorded daily and averaged weekly. Individual milk samples from 2 consecutive milkings were obtained once a week for component analysis. Rumen fluid was collected (n = 3 cows/treatment) at 4 time points per day at 7 and 21 DIM. Blood samples were collected within 1 h before feeding time for metabolite analysis and hyperketonemia diagnosis. Supplementation of FACW improved feed efficiency relative to control; this effect may be partially explained by a marginally significant reduction in dry matter intake from wk 3 to 7 for FACW-supplemented cows with no detected FACW-driven changes in milk yield, milk protein yield, and milk energy output compared with control. Also, there was no evidence for differences in intake of net energy for lactation, efficiency of energy use, energy balance, or body weight or body condition score change from calving to 45 DIM between treatments. Supplementation of FACW shifted rumen measures toward greater molar proportions of propionate and butyrate, and lesser molar proportions of acetate and valerate. Cows supplemented with FACW had greater plasma glucose concentrations in the period from 3 to 7 DIM and greater plasma insulin concentrations compared with control. Plasma nonesterified fatty acid and β-hydroxybutyrate concentrations were decreased in cows supplemented with FACW compared with control cows in the period from 3 to 7 DIM. These findings indicate that FACW may have improved the plasma metabolite profile immediately postpartum in dairy cows. Additionally, supplementation of FACW resulted in improved feed efficiency as accessed by measures of milk output relative to feed intake.     

离子液体催化聚乳酸丁醇醇解反应

以离子液体[Bmim][OAc]为反应介质和催化剂, 对聚乳酸 (PLA)丁醇醇解反应进行了研究。考察了反应温度、反应时间、离子液体用量、丁醇(n-butanol)用量对反应结果的影响。得到较佳工艺条件为:反应温度为150℃、反应时间为3 h、m([Bmim][OAc]):m(PLA)=0.2:1、n(n-butanol):n(PLA)=5:1。在上述条件下, PLA醇解反应转化率≥81%, 乳酸正丁酯收率≥70%。采用FT-IR技术对产品的结构进行了表征。 离子液体的回用性能结果表明:[Bmim][OAc]重复利用6次后, PLA转化率和乳酸正丁酯收率无明显变化。     

离子液体水溶液吸收模拟烟气中SO2

建立了一套放大脱硫装置, 利用该装置研究了乙醇胺乳酸盐([MEA]L)水溶液在不同条件下吸收SO₂的性能, 确定出了较优的实验条件, 并在该条件下进行吸收-解吸SO₂循环实验。研究结果表明:烟气中SO₂的去除率随[MEA]L中水分的增加而增加;SO₂的去除率随着气液比的减少而增加, 在气液比为420, SO₂浓度为2850～14280 mg·m^-3范围内时, 出口烟气中SO₂浓度均小于285 mg·m^-3, 满足排放标准;烟气中的CO₂对[MEA]L水溶液吸收SO₂没有影响;利用蒸汽对富液进行解吸再生, 解吸后的贫液可以继续使用, 并且仍具有很高的SO₂去除率。     

手性色谱法测定L-乳酸锌

研究高效液相色谱法测定乳酸锌中L-乳酸锌含量的方法,并对此方法学进行探讨。采用OA-5000手性色谱柱,1 mmol/L CuSO4·5H2O溶液为流动相,流速为1 mL/min进行色谱分离DL-乳酸锌,分离效果好。L-乳酸锌在0.147～3.675 mg/mL范围内呈现良好的线性关系,相关系数达0.999 9（n=6）;精密度实验相对标准偏差为0.044%;稳定性实验相对标准偏差为0.061%;平均回收率达（99.8±1.90）%,相对标准偏差仅为1.90%。表明此方法操作简便,结果准确可靠,可用于L-乳酸锌的准确测定和品质监控。     

More Than Meets the Eye Regarding Cancer Metabolism

In spite of the continuous improvement in our knowledge of the nature of cancer, the causes of its formation and the development of new treatment methods, our knowledge is still incomplete. A key issue is the difference in metabolism between normal and cancer cells. The features that distinguish cancer cells from normal cells are the increased proliferation and abnormal differentiation and maturation of these cells, which are due to regulatory changes in the emerging tumour. Normal cells use oxidative phosphorylation (OXPHOS) in the mitochondrion as a major source of energy during division. During OXPHOS, there are 36 ATP molecules produced from one molecule of glucose, in contrast to glycolysis which provides an ATP supply of only two molecules. Although aerobic glucose metabolism is more efficient, metabolism based on intensive glycolysis provides intermediate metabolites necessary for the synthesis of nucleic acids, proteins and lipids, which are in constant high demand due to the intense cell division in cancer. This is the main reason why the cancer cell does not “give up” on glycolysis despite the high demand for energy in the form of ATP. One of the evolving trends in the development of anti-cancer therapies is to exploit differences in the metabolism of normal cells and cancer cells. Currently constructed therapies, based on cell metabolism, focus on the attempt to reprogram the metabolic pathways of the cell in such a manner that it becomes possible to stop unrestrained proliferation.     

米根霉产L-乳酸耐温菌株的60Co-γ射线诱变选育

目前产L-乳酸的米根霉菌株的最适发酵温度为32℃,该温度较低,不利于产物分离且易染杂菌。以米根霉As3.819为出发菌株,采用60Co-γ射线进行诱变处理,以正突变率为指标,诱变剂量为400Gy,通过筛选得到耐38℃高温的5号突变株mut-5,经连续传代7次,遗传性状稳定。与出发菌株相比,发酵72h后,mut-5突变株发酵液中的乳酸含量提高了24.15%,乙醇含量降低了9.27%。乳酸脱氢酶(LDH)比活力提高了39.41%,乙醇脱氢酶(ADH)比活力有所下降,而对还原糖的利用速率以及生物量的积累均高于出发菌株。     

11 种保健酒中挥发性成分的分析

采用硅胶柱层析法结合气相色谱-质谱联用仪,对中国劲酒、竹叶青酒、张裕至宝三鞭酒、椰岛海王酒等11 种保健酒中的挥发性成分进行了分析,并通过标准品比对和NIST 11谱库检索进行了定性、定量研究。结果表明：11 种保健酒中共鉴定出37 种化合物,醇类6 种、烃类12 种、酯类9 种、醛类4 种、酸类2 种、酮类2 种、含氮化合物和酚类化合物各1 种,其中含量较大的成分有1-丙醇、2-甲基-1-丙醇、3-甲基-1-丁醇、乳酸乙酯、柠檬酸三乙酯、5-羟甲基糠醛和乙酸;通过内标法,对11 种保健酒中的乳酸丙酯进行了定量分析,线性回归方程为y =1.059 3x＋0.01（r=0.995）,含量范围在0.02～0.74 mg/L之间。检出限为0.005 mg/L ,定量限为0.01 mg/L。使用MATLAB 7.0软件,对中国劲酒、阳春牌滋补酒、沱牌枸杞酒以及椰岛海王酒、张裕至宝三鞭酒和竹叶青的挥发性成分进行了进行单因素方差分析和帕累托分析,结果表明：6 种酒样中烃类化合物的含量具有显著性差异;重要挥发性成分有3-甲基-1-丁醇、1-丙醇、2-甲基-1-丙醇、2-丁醇、5-羟甲基糠醛、丁香酚、乳酸乙酯、己酸乙酯、乙酸异戊酯、乙酸苯乙酯、癸酸乙酯、柠檬酸三乙酯、糠醛、肉桂醛、乙酸、苯乙烯、十四烷、十五烷、十六烷、1,4-二甲基苯、二苯胺。