超声酶促合成维生素A棕榈酸酯

研究了超声辐照下,在有机溶剂中以固定化脂肪酶Novozym435催化合成维生素A棕榈酸酯。考察了影响合成维生素A棕榈酸酯反应的诸因素(溶剂、底物摩尔比、底物浓度、反应时间、酶量和超声功率),并优化了反应条件:在10mL的正己烷溶剂中,0.164g维生素A醋酸酯和0.32g棕榈酸,在酶与维生素A醋酸酯的质量比为1∶4的固定化脂肪酶Novozym435催化下,超声功率为90W,反应6h,酯化率可达82%。

枚棕酸合成方法研究

以乙二醛为原料,在NaHCO3和Na2SO3存在下,利用残液复用、分子筛和金属Cu为催化剂,一步法制得高纯度的枚棕酸,研究了枚棕酸的合成工艺,该合成方法原料成本低,条件温和,绿色环保,枚棕酸收率可达25%,高于传统方法.

腐植酸类物质应用研究进展

腐植酸作为一种资源广泛存在于自然界中,它是影响环境生态平衡的重要因素,也是潜在的、可大力开发和综合利用的有机资源.腐植酸类物质具有多种活性官能团,具有酸性、亲水性、界面活性、阳离子交换能力、络合作用及吸附分散能力.本文对腐植酸进行了分类,综述了其应用领域以及腐植酸类物质应用中存在的问题和应用前景.

柠檬酸三正丁酯合成及乙酰化研究

对柠檬酸三正丁酯的合成进行了研究 ,对催化剂用量、反应温度、反应时间等条件进行了试验 ,找到了佳化工艺条件并进行了中试。在此基础上对柠檬酸三正丁酯的乙酰化反应进行了研究 ,对反应催化剂、原料进料比、反应温度、反应时间等条件进行了试验 ,找到了佳化工艺条件。为工业生产提供了必要的数据。

腐植酸含量测定的新方法

将容量法测定黄腐酸,重量法测定棕腐酸、黑腐酸的方法相结合。建立了腐植酸的新方法。该方法与原来的容量法、重量法比较更客观、更真实。

黄腐酸对奶牛DHI部分指标的影响

根据腐植酸在溶剂中的溶解度、颜色及分子量大小,可将其分为黑腐酸、棕腐酸和黄腐酸。黄腐酸分子量小,溶于酸、碱和水,易被细胞吸收,是腐植酸中主要的有效成分。

柠檬酸废渣制石膏板

在柠檬酸钙和柠檬酸生产中,往往排出大量"废"渣,污染环境.而这些柠檬酸废渣含硫酸钙达85%以上,符合国家二级天然石膏的标准,用它完全可以制多孔石膏板.其制作方法是:

化学降解法生产高活性黄腐酸及棕腐酸新技术——抗硬水中性及酸性水溶煤基酸

长期以来黄腐酸(FA)的来源皆采用FA含量在20％以上风化煤中直接提取,其方法不外乎丙酮-H_2SO_4法、离子交换树脂法及H_2SO_4法。这种来自煤中的天然FA是风化煤在自然环境中长期深度风化氧化的产物。一般风化煤所含FA都很低,没有提取FA的利用价值。我国富含FA的风化煤资源迄今只有河南巩县、山西晋城、新疆哈密,显然三个地区的总量与全国分布广、储量十分丰富的褐煤、泥炭。

河流底质中汞的形态分析方法研究

底泥中金属的形态分析广泛采用化学浸取法,系借用或修改土壤化学分析的方法而得,选用合适的试剂将不同地球化学相所结合的金属提取而分成数类;水溶态、可交换态,碳酸盐结合态、铁锰氧化物结合态、腐殖质结合态、有机质结合态以及残渣部分。本文结合实际河流样品的物相分析,以化学提取法研究汞的赋存形态,对不同化学提取剂的实验条件及提取效果进行了评价,并以相应的化合物进行了模拟实验。最后用汞污染严重的华北蓟运河表层底泥作为实例,验证了所拟操作程序的实用性。

Effects of Exogenous Organic Acids on Phosphorus Availability of Dark Brown Forest Soils and Phosphorus Absorption and Accumulation of Larix olgensis Seedlings with Nutrient Deficiency

Different proportions of A1 and B horizons dark brown forest soils （A1∶B=1∶2） were utilized to set the soil nutrient deficient conditions, and Larix olgensis seedlings were cultivated. By simulating organic acids concentrations in forest litter leachates of northeast China, the effects and mechanism of different concentrations of organic acid solutions on phosphorus （P） availability of dark brown forest soils and P absorption of Larix olgensis seedlings with nutrient deficiency were studied. The results showed that, compared with A1 horizon soils, available P contents of mixed soils in A1 and B horizons decreased, and P accumulation and efficiency of P uptake in root and leaves of Larix olgensis seedlings also decreased, but efficiency of P utilization increased. After treatments of exogenous organic acids, available P contents of mixed soils increased and the impact sequence of different organic acids were succinic acid 〉 citric acid 〉 oxalic acid; the concentration of 5.0 mmol/L had the best function, and the best effect of organic acids was at 20 d. Organic acids also increased P accumulation and efficiency of P uptake in roots and leaves of Larix olgensis seedlings, but decreased efficiency of P utilization. The impact strength of organic acids on P accumulation and efficiency of P uptake varied with treatment time, type and concentration of organic acids. The results of 20 d and 30 d in roots were higher than those of 10 d, however, the results of 10 d and 20 d in leaves were higher than those of 30 d, thus, at the earlier stage of organic acids treatments, more P absorbed were transferred to leaves, and at the later stage, more P would be accumulated in roots. The concentration of 10.0 mmol/L had the best function, and the impact sequence of different organic acids was succinic acid 〉 citric acid 〉 oxalic acid. Therefore, organic acids might contribute to P absorption and accumulation by Larix olgensis seedlings, final y increasing the adaptability and endurance of Larix olgensis seedlings to nutrient deficient soils.

Effects of Exogenous Organic Acids on Dehydrogenase Activity in Dark Brown Forest Soils under Nutrient Deficiency

Objective] This study aimed to investigate the effects of exogenous or-ganic acids on dehydrogenase activity in dark brown forest soils under nutrient defi-ciency. [Method] Different proportions of A1 and B horizon dark brown forest soils （A1∶B=1∶2） were utilized to establish soil conditions with nutrient deficiency for cultivation of Larix olgensis seedlings. The effects of oxalic acid, citric acid and succinic acid on dehydrogenase activity in dark brown forest soils under nutrient deficiency were studied systematical y by adding different concentrations of organic acid solutions. [Result] Under nutrient deficiency, dehydrogenase activity in dark brown forest soils was reduced significantly, and the reduction increased with the extension of stress duration. Most organic acid treatments improved dehydrogenase activity in nutrient-deficient dark brown forest soils, and the effects varied with different treatment du-ration and types and concentrations of organic acids. Furthermore, 10.0, 5.0 and 10.0 mmol/L organic acid treatments exhibited the most significant effects on day 10, 20 and 30, respectively. The increment of dehydrogenase activity in different durations showed a downward trend of 30 d〉20 d〉10 d; the improvement effects of three organic acids on dehydrogenase activity showed a downward trend of succinic acid〉 citric acid〉oxalic acid. [Conclusion] Exogenous organic acids improved signifi-cantly dehydrogenase activity in dark brown forest soils under nutrient deficiency and also improved the microbial activity and soil fertility to a certain extent.

鱼类的烹饪技巧

全世界吃鱼最多的国家在日本,鱼是鲜美又营养价值极高的海鲜,有优质蛋白质、丰富的不饱和脂肪酸棕-3,吃鱼还有助于预防心血管疾病、降低胆固醇,甚至抑制忧郁症等,对人体的好处非常多。但是,要怎么烹饪,才能将鱼最精华的营养吃进肚子里呢专家特别提供以下5个鱼料理小技巧,让你吃鱼吃出健康,花样变化无穷。使用好油涂抹鱼身再加食材点缀在烹调之前,先将鱼片双面刷上特级初榨橄榄油或椰子油,

Optimization of Wax Esters Production from Palm Fatty Acid Distillate and Oleyl Alcohol over Amberlyst 15

Wax esters were derived from long chain fatty acids and long chain alcohols with chain length of 12 carbons or more. These compounds have many potential applications in cosmetics, pharmaceuticals and food industries. The present work focuses on the synthesis of wax esters using palm fatty acid distillate and oleyl alcohol catalyzed by Amberlyst 15. Response surface methodology （RSM） based on a five-level, three-variable central composite design （CCD） was used to evaluate the interactive effects of synthesis, of amount of Amberlyst 15 catalyst （21.6-38.4% w/w）, reaction time （18-102 min） and molar ratio （palm fatty acid distillate to oleyl alcohol, 1：1.16-1：2.84） on the percentage conversion of palm fatty acid distillate. The optimum conditions derived via RSM were： amount of catalyst 33% w/w, reaction time 95 minute and palm fatty acid to oleyl alcohol molar ratio 1：2.7. The actual experimental conversion was 81.52% under optimum condition, which compared well to the maximum predicted value of 80.50%. Analysis of the yield showed that at optimum condition, 80.54% wax esters were produced.

Repression of PKR mediates palmitate-induced apoptosis in HepG2 cells through regulation of Bcl-2

The present study shows that double-stranded RNA-dependent protein kinase （PKR） regulates the protein expres- sion level and phosphorylation of Bcl-2 and plays an anti-apoptotic role in human hepatocellular carcinoma ceils （HepG2）. In various types of cells, saturated free fatty acids （FFAs）, such as palmitate, have been shown to induce cellular apoptosis by several mechanisms. Palmitate down-regulates the activity of PKR and thereby decreases the level of Bcl-2 protein, mediated in part by reduced activation of the NF-KB transcription factor. In addition to the level of Bel-2 protein, the phosphorylation of Bcl-2 at different amino acid residues, such as Ser70 and Ser87, is also important in regulating cellular apoptosis. The decrease in the phosphorylatiou of Bcl-2 at Ser70 upon exposure to palmitate is mediated by inhibition of PKR and possibly by c-Jun N-terminal kinase （JNK）, whereas the phosphory- lation of Bcl-2 at Ser87 is unaffected by palmitate or PKR. In summary, PKR mediates the regulation of the protein level and the phosphorylation status of Bel-2, providing a novel mechanism of palmitate-induced apoptosis in HepG2 cells.

ON THE DIVISION OF NORTH BOUNDARY OF SUBTROPICALZONE ACCORDING TO THE COMPOSITIONS AND PROPERTIES OF SOIL HUMUS

In this paper predecessors′achievements about the division between subtropical zone and warm temperate zone on the south slope of Funiu Mountain are firstly summarized, and the cause why these viewpoints about the division are different also has been presented. Seven soil profiles at different heights above sea level are dug along the south slope of Funiu Mountain. Many compositions and properties of soil humus have been analyzed in laboratory. A comprehensive study has been made about the division according to the compositions and properties of soil humus with mathematical method. During the analysis process eight indexes have been used, such as altitude, organic carbon, humic acid (HA), fulvic acid (FA), the ratio of humic acid and fulvic acid (HA/FA), two extinction coefficients (E4,E6), and their ratio (E4/E6).The result indicates that the boundary is at about 1000 meters above sea level.

Relationship between Ethanol and 2-phenylethanol Stress Tolerance and Fatty Acid Compositions of Saccharomyces cerevisiae

In the present study, we investigated of the ethanol （Eth）, 2-phenylethanol （2-PE） and ethanol/2-phenylethanol （Eth/2-PE） stress tolerance and established relationship between stress tolerance and fatty acid compositions of wine yeast strain S. cerevisiae UCM Y-524 in relation to different cultivation factors. Changes in cell membrane fatty acid profiles studied under different temperature and media. The active oxygenation, semi-aerobic cultivation supplemented Tween 80 conditions were used in different combinations. The concentrations of 2-PE and Eth, the fatty acids methyl esters （FAMES） in the media were measured by GC-MS analyses. 2-PE, Eth, FAMES were identified by NIST02 MS database at the 2-PE and Eth standard solution （Merck, Germany）, bacterial FAMES standard （Supelco）. Palmitoleic and oleic acid were dominated for S. cerevisiae UCM Y-524. The unsaturated/saturated fatty acid （UFA/SFA） ratio was higher than five for S. cerevisiae UCM Y-524 at 14 ~C in simple medium and about more than three for other conditions. It has been found that yeast cells grown in the presence of the 2-PE, Eth and Eth/2-PE appear to increase the amount of unsaturated fatty acids, especially oleic acid, in cellular lipids especially under active oxygenation supplemented with Tween 80. S. cerevisiae UCM Y-524 has a higher tolerance under 2-PE, Eth and Eth/2-PE stress at 28 ~C in a simple medium under aerobic conditions. A higher concentration of unsaturated fatty acids in the membrane S. cerevisiae UCM Y-524 and a lower temperature under aerobic conditions, has been considered to have a positive influence on the excretion of 2-phenylethanol.

Reaction kinetics of isopropyl palmitate synthesis

In this study, the kinetics of isopropyl palmitate synthesis including the reaction mechanism was studied based on the two-step noncatalytic method. The liquid-phase diffusion effect on the reaction process was eliminated by adjusting the stirring rate. The results showed that the two-step reaction followed a tetrahedral mechanism and conformed to second-order reaction kinetics. Nucleophilic attack on the carbonyl carbon afforded an intermediate, containing a tetrahedral carbon center. The intermediate ultimately decomposed by elimination of the leaving group, affording isopropyl palmitate. The experimental data were analyzed at different temperatures by the integral method. The kinetic equations of the each step were deduced, and the activation energy and frequency factor were obtained. Experiments were performed to verify the feasibility of kinetic equations, and the result showed that the kinetic equations were reliable. This study could be very signi ficant to both industrial application and determining the continuous production of isopropyl palmitate.

Process Improvement on the Lipase-Catalyzed Synthesis of Oleyl Palmitate, a Wax Ester via Response Surface Methodology （RSM）

High performance enzymatic synthesis of oleyl palmitate, a wax ester was carried out by lipase-catalyzed esterification of palmitic acid and oleyl alcohol. Response surface methodology （RSM） based on 5-level, 3-variable of centre composite rotatable design （CCRD） was used to evaluate the interactive effects of synthesis, of temperature （40-60 ℃）; amount of enzyme （0.1-0.4 g） and substrate molar ratio of oleyl alcohol to palmitic acid （1：1-4：1） on the percentage yield of wax ester. All reactions were fixed at 1 hour of reaction time. The optimum condition obtained from RSM for the reactions were temperature of 57.9 ℃, enzyme amount of 0.26 g and molar ratio of substrates of 2.92. The actual experimental yield was 91.2% under the optimum condition, which compared well with the maximum predicted value of 92.0%. Comparison of predicted and experimental values reveal good correspondence between them, implying that empirical models derived from RSM can be used to adequately describe the relationship between the factors and response in the synthesis of oleyl palmitate.

Chemical component and antimicrobial activity of volatile oil of Calycopteris floribunda

The volatile oil of leaves and barks of Calycopteris floribunda was examined by gas chromatography-mass spectrometry (GC-MS). 52 volatile chemical components in leaves were identified. The antimicrobial assay of oils in the leaves and barks was carried out by disk diffusion method in vitro. The major components (mass fraction) in leaves are caryophyllene oxide (13.79%),n-hexadecanoic acid (11.91%) and β-caryophyllene (10.45%). Ten constituents are identified accounting for about 99.98% of the total volatile oil in the bark. Among these components,n-hexadecanoic acid (59.18%),linolic acid (12.70%) and butyl octyl phthalate (8.21%) are the major constituents. The oils exhibit strong antimicrobial activity and display more potent against bacteria than fungi.

Ternary Liquid-Liquid Equilibrium for Systems of Fatty Acid Methyl Ester(Methyl Palmitate/Methyl Stearate)+Ethanol+Glycerol at Atmospheric Pressure

Liquid-liquid equilibrium data of two ternary systems methyl palmitate+ethanol+glycerol and methyl stearate+ethanol+glycerol at(318.2 and 333.2)K and atmospheric pressure were measured. The values of distribution coefficient and selectivity were calculated, which indicates that glycerol can be separated from fatty acid ester by using ethanol as an extraction solvent. The consistency of the isothermal tie-line data were checked by the Othmer-Tobias equation. The correlation coefficients R2 are higher than 0.993,9 for all the fitted curves. The NRTL activity coefficient model was applied to the correlation of the measured tie-line data. The root mean square deviation(RMSD)values are less than 0.007 for all the systems, which shows a good predictive capability of this model for such systems.