Identification and characterization of conjugated linolenic acid isomers by Ag+-HPLC and NMR

Interest in the biological activity of conjugated linolenic acids (CLnA) is growing. Technically, previous methods could not fully characterize and identify CLnA isomers. The present study is the first report on application of silver ion impregnated high-performance liquid chromatography (Ag+-HPLC) into separation of CLnA methyl ester (CLnAMe) mixture. Compared with the GC and reversed-phase HPLC techniques, Ag+-HPLC could resolve and separate CLnAMe isomers into three clusters of peaks namely ttt, ctt and ctc geometrical groups. Each positional isomer belonging to the same geometrical group could be further separated by Ag+-HPLC. Quantitative 13C NMR properties of CLnAMe mixture were subsequently studied. Olefinic signals in the CLnAMe mixture were assigned and used to quantify each isomer in combination with Ag+-HPLC. The present study provided a detailed analysis of a complex CLnA mixture and may have an important application in future studies dealing with synthesis, oxidative stability, and bioactivity of individual CLnA isomers.     

Hypolimnetic anoxia and sediment oxygen demand during stratification in a drinking water reservoir

Journal of Soils and Sediments - Although hypolimnetic anoxia is a common occurrence in deep lakes and reservoirs, understanding the processes of oxygen depletion in water columns and sediment is...     

Selenium Removal from Irrigation Drainage Water Flowing Through Constructed Wetland Cells with Special Attention to Accumulation in Sediments

A flow-through experimental wetland system has been under investigation since 1996 to remove selenium (Se) fromagricultural drainage water in the Tulare Lake Drainage Districtat Corcoran, California, U.S.A. The system consists of ten cellswhich have dimensions of 15 × 76 m continuously flooded andvarious substrates planted. The objectives of this article are topresent the overall performance in Se removal after establishingthe wetland for three years, and to examine factors affecting Seremoval with special attention to accumulation in the sediments.In 1999, The wetland cells reduced Se from inflow water by 32 to65% in concentration and 43 to 89% in mass. Vegetationplays an important role in Se removal as non-vegetated cellshowed the least removal of Se. The inflow drainage water wasdominated by selenate (Se(VI), 91%) with smaller percentages ofselenite (Se(IV), 7%) and organic Se (org-Se(II-), 2%). Theoutflow water from the cells contained an average of 47% Se(VI),32% Se(IV) and 21% org-Se indicating reduction processesoccurring in the wetland cells. The surface sediment appears as alarge sink of Se removal. The highest Se concentration was foundin fallen litter, followed by the fine organic detrital layer onthe sediment surface. The sediment Se concentration dramaticallydecreased with increasing sediment depth. The mass distribution of Se, however, was sediment (0-20 cm) > fine detrital matter >fallen litter. Fractionation of surface sediment (0-5 cm) reveals that elemental Se was the largest fraction (ave. 47%) followedby organic matter-associated Se (34%). Soluble, adsorbed, and carbonate-associated Se accounted for 1.2, 3.1 and 2.5% ofthe total sediment Se, respectively. The major Se sink mechanism in the cells is the reduction of selenate to elemental Se andimmobilization into the organic phase of the sediments.     

Considerations regarding the use of hyperspectral imaging data in classifications of food products, exemplified by analysis of maize kernels

Development of robust analytical procedures is critical when using hyperspectral imaging technology in food technology and agriculture. This study used near-isogenic inbred corn lines to address two basic questions: (1) To what extent is classification accuracy increased by grinding maize kernels? (2) Can the classification accuracy of two near-isogenic inbred lines be increased by using a spectral filter to classify only certain hyperspectral profiles from each image cube? Whole kernels and ground kernels in two particle intervals, 0.250-0.354 mm (size 1) and 0.354-0.841 mm (size 2), were examined. Spectral profiles acquired from ground kernels had higher spectral repeatability than data collected from whole kernels. The classification error of discriminant functions from whole kernels was >3 times lower than that of size 1 ground particles. Applying a spectral filter to input data had negligible effect on classifications of hyperspectral profiles from whole kernels and size 2 ground particles, but for size 1 ground particles a considerable increase in accuracy was observed. Independent validation confirmed that distinction between wild type and mutant inbred maize lines could be conducted with >80% accuracy after the proposed spectral filter had been applied to hyperspectral profiles of size 1 ground particles. A combination of discriminant analysis and regression analysis could be used to accurately predict mixture ratios of the two inbred lines. The use of spectral filtering to increase the level of spectral repeatability and the use of hyperspectral imaging technology in large-scale commercial operations are discussed.     

大麦叶绿体突变体的类囊体膜蛋白质及叶绿体超微结构的研究

比较研究了大麦黄绿突变体与其原始品种“矮秆齐”的叶绿体类囊体膜蛋白质及叶绿体超微结构。结果表明,突变体比对照少了一条23kd 多肽。已经证明该突变体缺叶绿素蛋白质复合体Ⅱ(即 CPⅡ),故推论23kd 为 CPⅡ特异多肽。此外,17.5及18.3kd 两个峰,突变体也较对照明显下降。叶绿体超微结构方面的观察结果表明,突变体的基粒片层     

Differential recovery of lupin proteins from the gluten matrix in lupin-wheat bread as revealed by mass spectrometry and two-dimensional electrophoresis

Bread made from a mixture of wheat and lupin flour possesses a number of health benefits. The addition of lupin flour to wheat flour during breadmaking has major effects on bread properties. The present study investigated the lupin and wheat flour protein interactions during the breadmaking process including dough formation and baking by using proteomics research technologies including MS/MS to identify the proteins. Results revealed that qualitatively most proteins from both lupin and wheat flour remained unchanged after baking as per electrophoretic behavior, whereas some were incorporated into the bread gluten matrix and became unextractable. Most of the lupin α-conglutins could be readily extracted from the lupin-wheat bread even at low salt and nonreducing/nondenaturing extraction conditions. In contrast, most of the β-conglutins lost extractability, suggesting that they were trapped in the bread gluten matrix. The higher thermal stability of α-conglutins compared to β-conglutins is speculated to account for this difference.     

本溪山区极端降水指数的变化特征分析

为了进一步探讨降水及洪涝灾害发生规律,合理开发利用本溪山区水资源,利用本溪草河口气象站1953—2012年逐日降水资料,分析了本溪山区6个极端降水指数的变化趋势。结果表明：本溪山区年降水量年际差异较大,年降水量无显著的变化趋势;四季降水量也无明显的变化趋势。年降水日数呈明显的减少趋势,从1974年本溪山区降水日数开始减少;除春季降水日数变化趋势不明显外,其他各季均呈显著的减少趋势变化;夏季在1976年,秋季在1987年发生突变。降水强度无明显的变化趋势;最大5日降水量趋势变化不明显,但年际间差异较大;年极端降水事件无显著的变化趋势,20世纪50、60、80年代为偏多时期。     

吨田宝对旱地小麦生长发育及产量形成的影响

为研究不同生育时期喷施不同浓度吨田宝对旱地小麦生长发育和产量形成的影响,于2013—2014年度在山西农业大学闻喜试验基地进行了旱地小麦起身期和挑旗期喷施不同浓度吨田宝的试验。结果表明,起身期喷施吨田宝,促进了拔节期根系发育,减缓成熟期根系衰老,增加拔节期、开花期的叶面积指数和各生育时期干物质量,随浓度大主要通过提高穗数提高产量;挑旗期喷施吨田宝有利于促进有效穗数的形成,随浓度增大主要通过增加穗粒数、千粒重提高产量;起身期、挑旗期配合喷施不同浓度吨田宝增加了开花期的叶面积指数,提高了开花期和成熟期干物质量,显著提高了穗数、穗粒数、产量,增产幅度达5.8%~10%。总之,起身期和挑旗期以1:1,浓度为每公顷750 mL/225 kg水喷施吨田宝显著提高穗数和千粒重,增产效果最好。     

潍坊地区一次强冰雹天气成因分析

为了避免冰雹灾害给社会造成不必要的损失,达到防灾减灾的目的,更好地做好冰雹天气预报,笔者利用常规观测资料、雷达和FY-2E卫星TBB资料,对2012年6月初潍坊市出现的一次典型冰雹天气过程进行了成因分析。结果表明：此次冰雹天气过程发生在东北冷涡和前倾槽的环流背景下,强烈的上升运动为此次天气提供了动力条件,地面中小尺度辐合线是此次冰雹天气的触发机制。适宜的0℃层和-20℃层高度及大的环境风垂直切变有利于雹粒的增长。另外,此次天气发生在对流云团发展最旺盛的时段,位置位于大于232 K的冷云盖移动方向的前端到等温线梯度大值区附近,这对冰雹天气落区的预报有较好的指示意义。