碱性脂肪酶固定化条件及其催化生物柴油的研究

该文以改性的硅胶为载体,通过戊二醛交联固定化碱性脂肪酶,得到较佳固定化条件：当戊二醛浓度为0.8 g/L,给酶量为30 U/g时,酶活回收率效率达到90%以上。通过改变溶剂的种类、给酶量、含水率、底物摩尔比、甲醇的流加方式等参数,考察了脂肪酸和甲醇在固定化碱性脂肪酶催化下合成生物柴油的工艺条件,试验结果表明在20 mL正己烷,给酶量7.5 g（12 U/g）,脂肪酸10 g,酸醇摩尔比为1︰1.2,含水率4%条件下,分3次加入甲醇,40℃反应8 h,反应体系酯化率达到了82%。     

Effects of Soybean Active Peptides on Performance and Serum Lipid of 14-day Old Early Weaned Piglets

This purpose was to evaluate the efficacy of soybean active peptides (SAP) in 14-day old early weaned piglets feed. Eighteen crossbreed piglets Duroc x Landrace x Yorkshire (14-day old) were randomly divided into three groups with six piglets each group. Control was fed with 8% animal plasma (AP). Trial 1 was fed with 4.9% AP and 4.9% SAP. Trial 2 was fed with 12.62% SAP. This raising period was 30 days and divided into three periods with earlier period (0-15 days), latter period (16-30 days) and whole period (0-30 days). The results showed that average daily gains (ADG) in trial 1 were increased 16.33%, 12:64% and 13.94% (P ＞0.05) and Efficiency of feed conversions (EFC) improved 17.35%, 11.40% and 13.46% than control in respective periods; ADG in trial 2 were reduced 12.24%, increased 4.21% and reduced 0.40% (P＞0.05) and EFC were improved 19.81%, 13.08% and 15.76% than control in respective periods. Means of TG and LDL-C/HDL-C in trial 1 were lowest in three groups and reduced 6.54% (P ＞0.05) and 0.96% than control. Means of TG, TC, LDL-C, HDL-C, LDL-C/HDL-C were the highest in trial 2 among three groups and increased 8.93% (P ＞0.05), 39.69% (P ＜0.05), 34.94% (P ＞0.05), 27.31% (P ＞0.05) and 5.96% than control respectively. It was concluded that substituting part Ap for SAP in 14-day old piglets Feed was practicable.     

Functional characterization of FaCCD1: a carotenoid cleavage dioxygenase from strawberry involved in lutein degradation during fruit ripening

A gene encoding a carotenoid cleavage dioxygenase class 1 enzyme (FaCCD1) was identified among a strawberry fruit expressed sequence tag collection. The full-length cDNA was isolated, and the expression profiles along fruit receptacle development and ripening, determined by quantitative real time polymerase chain reaction, showed that FaCCD1 is a ripening-related gene that reaches its maximal level of expression in the red fully ripe stage. FaCCD1 was expressed in Escherichia coli, and the products formed by the recombinant protein through oxidative cleavage of carotenoids were identified by liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry analyses. The FaCCD1 protein cleaves zeaxanthin, lutein, and beta-apo-8'-carotenal in vitro. Although beta-carotene is not a good substrate for FaCCD1 in vitro, the expression of FaCCD1 in an engineered carotenoid-producing E. coli strain caused the degradation of beta-carotene in vivo. Additionally, the carotenoid profile in strawberry was analyzed by high-performance liquid chromatography-photodiode detection, and a correlation between the increase of the expression level of FaCCD1 during ripening and the decrease of the lutein content suggests that lutein could constitute the main natural substrate of FaCCD1 activity in vivo.     

Determination of ciprofloxacin, the major metabolite of enrofloxacin, in milk by isopotential fluorimetry

A new method for the determination of ciprofloxacin, the major metabolite of enrofloxacin, for concentrations between 20 and 200 ng/mL by means of matrix isopotential synchronous fluorescence spectrometry and derivative techniques is proposed. This new method is useful for the determination of compounds in samples with unknown background fluorescence, such as ciprofloxacin in whey, without the need of tedious preseparation. The determination was performed in an ethanol/water medium (20% v/v) at pH 4.8, provided by adding a sodium acetate/acetic acid buffer solution. Since enrofloxacin is widely used as an antibacterial agent in veterinary medicine, the method was successfully applied to the determination of its main metabolite in milk. An exhaustive statistical analysis has been developed to all calibration graphs. This treatment includes robust regression such as least median of squares, which also detects outliers and leverage points. The overall least-squares regression has been applied to find the more exact straight line that fits the experimental data. The error propagation has been considered to calculate the detection limit and the repeatability of the method.     

100 years of Sediment History of Heavy Metals in Daya Bay, China

Interdisciplinary studies on aquatic environments and cross-validation of laboratory vs. field results will likely increase the need for simultaneous use of large- and small-scale ultrafiltration systems. In this study, a comparison of two ultrafiltration systems differing in scale (PrepScale and PelliconXL, Millipore; membrane areas 0.54 m² and 0.005 m², respectively), was made for the cut-offs 3 and 300 kDa. Large systems are useful for their high permeate throughput, while small systems are necessary when the amount of sample is limited. The ability of PrepScale and PelliconXL systems to provide comparable results for organic carbon fractionation was studied for polysaccharide solutions and natural freshwaters. In the latter, the colloidal proportions of different trace metals (V, Cr, Mn, Co, Ni, Cu, Sb, and U) were also determined. Although the colloidal proportions obtained with PelliconXL 3 kDa were sometimes slightly higher than with PrepScale 3 kDa (principally for DOC and U in natural waters), Mann–Whitney statistical test showed no significant difference in the overall fractionation properties of the two systems. Our observations show that reaching high concentration factors lead to a strong modification of colloids size distribution in the range 50–2,000 nm and thus low concentration factors are preferable to preserve the colloid integrity.     

进风位置对纵向通风叠层鸡舍气流和温度影响CFD模拟

为提高鸡舍夏季通风效率,改善舍内环境条件,该文通过计算流体力学(computational fluid dynamics, CFD)模拟分别探究了进风口内侧加设导流板及不加设导流板时,进风位置对叠层笼养鸡舍舍内及笼内气流、温度及分布的影响。鸡舍模型通过现场试验进行验证。结果表明:在进风口内侧不加设导流板时,近进风口区域(距首个笼17.5 m之内鸡笼区域)笼内平均风速随着进风位置与鸡笼间距离增加而增大,最大增幅为0.54m/s。而当进风口内侧加设导流板时,不同进风位置时对笼内平均风速相对差异小于10%。同时,随着进风位置与鸡笼间距离增加,近进风口处笼内气流分布均匀性增加,笼内温度呈降低趋势且其分布趋于均匀。但进风位置对笼内环境影响范围有限,文中研究显示,进风位置对气流速度的影响范围为距首个笼27 m之内笼内区域,对气流分布均匀性的影响范围为距首个笼45 m之内笼内区域,对温度分布的影响范围为距首个笼18 m之内笼内区域。研究表明,在叠层鸡舍夏季通风系统进风位置设计中,应尽量设计在山墙,及保证进风口与鸡笼区域无重合,使得进风气流充分发展后进入鸡笼,有助于减少笼内通风弱区及涡流区域。     

Reduction of Pb availability during surficial leaching in different types of soils with addition of apatite and oxalic acid

Purpose

Pb contamination in soil is of great environmental concern due to its high exposure to human, especially on surface soil. However, the study regarding effect of Pb leaching on its remediation in different soils is still scanty.

Materials and methods

Red soil (RS, acidic), sandy soil (SS, alkaline), and yellow-brown soil (CS, neutral) were collected in this study. Bioapatite (BAp) and fluorapatite (FAp) were applied as P source to remediate Pb contamination. In addition, oxalic acid was added to enhance the solubility of apatite and hence the immobilization of Pb(II). Techniques of ICP, SEM-EDX, and XRD were utilized to investigate the concentration, distribution, and mineralization of Pb.

Results and discussion

Addition of BAp, in contrast to FAp, significantly reduced available Pb concentrations in soil. However, the remediation is not successful in the middle and bottom layers. This is correlated with the Pb leaching and relatively low solubility of BAp. The combination of oxalic acid and BAp dramatically reduced available Pb concentrations (80–99%) in all soil layers, primarily due to the enhanced P release from BAp by acid addition. Moreover, difference of available Pb concentrations (between top and bottom layers) in RS was 126 mg/kg, which is significantly higher than those for CS (5 mg/kg) and SS (21 mg/kg). Then, available Pb concentration in RS could be over ten times of that in CS, suggesting that Pb leaching is one of the negative factors influencing effects of remediation. Furthermore, the aggregation of Pb and salt-induced Pb mineralization in SS were confirmed by SEM-EDX and XRD analyses.

Conclusions

Rates of Pb leaching follow the order of RS > SS > CS. The effects of remediation on Pb availability can be reduced by Pb leaching, especially in RS. The effect of remediation in SS is also limited due to its alkalinity and salt coupling effect. In consequence, CS is the most suitable soil type for remediation via combination of BAp and oxalic acid. This study elucidates the critical leaching effects of Pb on remediation of surface soil.

     

Effects of EGF or bFGF on the development of porcine parthenogenetic embryos in vitro

Epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) were added into the culture medium in different culturing stages. The effects of EGF or bFGF on the development of porcine parthenogenetic embryos were studied in vitro. The results were as follows: The addition of EGF significantly enhanced the cleavage rate of porcine parthenogenetic embryos (P < 0.05). The addition of EGF or bFGF also significantly enhanced the rate of blastocysts formation of 2–4-cell porcine parthenogenetic embryos (P < 0.05). Additionally, the group of bFGF had more numbers of blastocysts and higher rates of blastocysts formation than the groups of EGF and the control. In conclusion, EGF and bFGF were found propitious to the development of porcine parthenogenetic embryos in vitro, and bFGF increased the quality of blastocysts by increasing the total cell number in porcine parthenogenetic embryos. __________ Translated from Acta Veterinaria et Zootechnica Sinica, 2007, 38(1): 36–39 [译自: 畜牧兽医学报]     

基于支持向量回归粒子滤波器的运动员实时跟踪方法

提出了一种用支持向量回归改进粒子滤波器的实时跟踪算法, 并用于足球比赛中. 实验证明, 通过支持向量回归来重新估计粒子权值能有效提高跟踪系统的鲁棒性和精确性.     

章丘大葱子叶再生体系建立及再生株倍性鉴定

 以章丘大葱子叶为材料,研究了不同激素配比对愈伤组织诱导和继代、芽分化、芽点的伸长及根诱导的影响,并对获得的再生植株进行了鉴定。结果表明,诱导章丘大葱子叶产生愈伤组织、愈伤组织的继代培养、愈伤组织芽分化、芽点的伸长及诱导生根的最佳培养基及激素配比分别为：MS+2,4-D 2.0mg/L+KT 0.5mg/L、MS＋2,4-D 2.5mg/L＋KT 0.5mg/L、MS+2,4-D 0+KT 1.0mg/L、MS+KT 0.5mg/L和MS基本培养基;试管苗经驯化移栽后,共有22株成活,成活率为92%,对成活的再生植株进行形态学、叶片气孔及根尖染色体鉴定表明,共有3株发生变异,其中2株为外部形态上的变异,而另一株为染色体的加倍变异。