Modified method for electron capture gas-liquid chromatographic determination of diethylstilbestrol residues in urine of fattened bulls

A gas-liquid chromatographic (GLC) method with electron capture (EC) detection was developed for determining diethylstilbestrol residues in the urine of fattened bulls. Diethylstilbestrol (DES) is extracted into benzene, and then into 1N sodium hydroxide. The pH of the phenolic fraction (alkaline phase) is adjusted to 10.2 and DES is extracted again into benzene. Sample extracts are cleaned up on silica gel. Trifluoroacetic anhydride (TFAA) is used as acylation reagent, and the derivatized sample is chromatographed on a 3% OV-17 column and measured with a 63Ni EC detector. The method is suitable for determining residues at levels as low as 2 ppb.     

西北典型区社会经济条件对退耕还林(草)政策实施影响的分析

通过对青海省湟中县人户调查,运用灰色关联法,对不同社会经济条件下农户的退耕还林状况进行了分析。结果表明,增加农户经济收入、改变农户家庭收入构成直接影响到农户退耕还林的积极性;户主年龄、受教育程度、家庭规模对退耕还林政策的实施也有不同程度的影响。     

我国主要农区秸秆还田试验总结

本文是 1999年全国 19个省市 10 7份秸秆还田的试验材料的归纳和总结。介绍了我国各主要农区的气候、作物、种植制度、秸秆还田的方法及秸秆还田的增产、改土培肥效果 ,反映了我国各主要农区的秸秆还田现状 ,可为各地的秸秆还田提供参考     

中国土壤系统分类中盐成土及其相关土壤诊断标准的修订建议

对土壤进行科学分类是土壤资源开发和利用的基础,也是土壤调查制图的基础,在农业生产、土地利用的决策和管理中发挥着重要作用,标志着土壤科学的发展水平.目前国际上土壤分类主要有《美国土壤系统分类》(以下简称《ST》)[1]和《世界土壤资源参比基础》(以下简称《WRB》)[2],我国从1984年开始的中国土壤系统分类研究,也已形成了具有中国特色的《中国土壤系统分类》(以下简称《CST》)[3]成果.这三个分类体系都是以定量化的诊断层和诊断特性为基础的多阶层土壤分类体系.     

Hydroponics: Its history and use in plant nutrition studies

Hydroponics is a widely and frequently used technique for growing plants without soil, providing for a considerable degree of control of the elemental environment surrounding the root. The technique has an interesting history of development and use dating back into the mid 18th‐century, although the growing of plants in nutrient rich water may have dated back into the early history of man. The determination of the essential elements required by plants were discovered using solution culture techniques. This paper discusses the past history of solution culture as well as its importance and use today.     

用0.25 mL细管冷冻保存猪精液的实验研究

本研究旨在建立优化的猪精液冷冻保存方法。实验表明，采用ZO液对猪精液进行预稀释，室温平衡1h，加入冷冻I液后于5℃水浴平衡1.5 h，再加入冷冻II液平衡2 h后装入0.25 mL细管，液氮面上3 cm处平衡10 min投入液氮，解冻时采用37℃水浴30s，可获得最佳冷冻效果。采用该优化方案，猪冷冻精液解冻后的精子活力可达0.58。     

Comparison of two methods for field grow of puncture vine (Tribulus terrestris L.) in Slovakia

One of the most claimed aphrodisiac plant is puncture vine (Tribulus terrestris L.) known as ‘plant Viagra’. This herb, growing especially in South and East Europe, is used for pharmaceutical purposes, due to its content of furostanol saponins which have stimulant effects on natural testosterone levels. Puncture vine grows as a weed on sandy soils areas. A study aimed to the introduction of puncture vine into large cultivation scale was carried out. Two different methods of cultivation were compared and production of biomass and evaluation of the content of furostanol saponins were done. Transplantation of seedlings raised in the greenhouse into the open field was more effective for the production of high amount of biomass and active components than using plants that are directly sown. The transplantation of seedlings into open field is suitable for the puncture vine cultivation as it increases biomass production.     

Enterotoxigenicity and cytotoxicity of Bacillus thuringiensis strains and development of a process for Cry1Ac production

Bacillus thuringiensis is indistinguishable from Bacillus cereus except for the production of insecticidal crystal proteins (ICPs). B. thuringiensis strains may show enterotoxin profiles and toxin levels similar to those of B. cereus strains isolated from food-poisoning cases. It is important for the food industry and farmers to consider that with the application of B. thuringiensis strains to crops, their spores may be introduced into the human food chain. In this study, 59 B. thuringiensis strains were assayed for their hemolysin BL (HBL) using a BCET-RPLA kit and their cytotoxicity to Chinese hamster ovary (CHO) cells. The enterotoxin titer was as high as that of B. cereus diarrheal-type strain ATCC 49064. In an attempt to obtain a food safety strain for bioinsecticide use, in this study, a 3.5-kb cry1Ac DNA fragment was amplified with PCR from the total DNA of B. thuringiensis subsp. kurstaki CCRC 11502 and cloned into the Bacillus expression vector pHY300PLK. The alpha-amylase promoter, amyE, was then introduced into the promoter region and, afterward, the recombinant plasmid pHYe1Ac35 was introduced into a non-enterotoxigenic and non-cytotoxic B. thuringiensis subsp. kurstaki Tt14 strain. The transformant, without any detectable enterotoxigenicity or cytotoxicity, produced Cry1Ac toxin properly, and its insecticidal activity against Trichoplusia ni larvae was found to be satisfactory.     

Evaluation of Field-Applied Fresh Composts for Production of Sod Crops

Application of compost to cropland potentially can use large quantities of compost and serve as an alternative to waste disposal into landfills. This study was conducted to evaluate the suitability of field-applied composts of mixed municipal solid wastes, biosolids, leaves, and agricultural wastes for production of wildflower and grass sods. The composts were applied one inch thick on the soil surface. In half the plots, the composts were left on the surface as a mulch and in the other half, composts were worked into the top two inches of soil. The effects of the composts on wildflower, grass, and weed germination and growth and on wildflower diversity and flowering were investigated for two growing seasons. Wildflower and grass quality did not differ whether the composts were applied as a mulch or incorporated into the soil. In the first year, limited growth in apparently immature biosolids-woodchips and mixed MSW composts was attributed to high concentrations of ammonium or soluble salts. The detrimental effects of biosolids-woodchips compost which had high initial ammonium-N concentrations remained into the second season. In the first season, N from composts or fertilizers stimulated weed growth and resulted in poor crop quality. In the second season, crops had a competitive edge over the weeds, and N from the compost improved crop quality. Wildflower diversity and total amount of bloom improved as the N status of the media increased. Weed control and mature compost with readily available N and low soluble salt concentrations are required for high crop quality in the first season.     

1951—2014年洞庭湖水沙阶段性演变特征及驱动因素分析

基于洞庭湖1951-2014年实测径流量和输沙量数据,采用Mann-Kendall检验、滑动t检验和有序聚类分析等多种统计方法分析洞庭湖水沙演变特征,并以回归曲线拟合及归-化曲线对降水量、径流量和输沙量之间的相互关系进行分析,以期确定影响洞庭湖水沙变化的驱动因素.结果表明:(1)入出湖径流量、输沙量的突变年份有差异,入湖径流量、出湖径流量为1971年,入湖输沙量为1985年,出湖输沙量为1970年;(2)洞庭湖入湖径流量具有以分段衰减为特征的演变过程,1972-1977年表现最明显;(3)入湖输沙量呈现分段衰减的阶段性演变特征,2004-2014年间多年平均输沙量减幅最大,衰减率为75.34％;(4)入湖、出湖径流量在1951-1971年和1978-1985年主要受降水量变化驱动,1972-1977年和1986-2014年主要受沙滩子自然裁弯、葛洲坝水电站、五强溪水库、三峡工程等人类活动影响;(5)1951-1971年入湖径流量的多寡对入湖输沙量产生一定影响,1972-2014年影响输沙量减少的主要因素是水利枢纽工程.因此,洞庭湖流域水沙过程的不同阶段其主导驱动因素有所差异.其中,入湖径流1972-1977,20042014年2个阶段及出湖径流1976-1985,2004-2014年2个阶段以水利枢纽工程驱动为主,其余2个以降水量变化驱动为主.     

Genetic diversity and population structure of worldwide eggplant (<Emphasis Type="Italic">Solanum melongena</Emphasis> L.) germplasm using SSR markers

Two hundred and eighty-seven worldwide eggplant accessions were examined for genetic diversity and population structure analysis with 45 SSR markers. The results resolved 242 alleles across all the accessions. Gene diversity ranged from 0.104 to 0.832 with an average of 0.558. Polymorphic information content ranged from 0.102 to 0.815 with an average of 0.507. The genetic diversity analysis classified all accessions into four groups, and the data showed that gene exchanges occurred in two groups during germplasm introduction, domestication, and improvement; however, the frequency was low. Population structure analysis classified 269 accessions into two subgroups, and the remaining 18 accessions were defined as admixed. The accessions from the same geographic origin tend to be clustered into same group. These results provide new insights into the exploitation of genetic diversity of germplasm for eggplant breeding program.     

Measurement of protein synthesis by soil bacterial assemblages with the leucine incorporation technique

The incorporation of [¹⁴C]-leucine into protein by soil organisms was measured both in soil slurries and for bacteria extracted from soil by homogenization-centrifugation. The result was compared with thymidine incorporation. Using a soil slurry, 9.1×10^-10 mol leucine h^-1g^-1 dry weight of soil was incorporated into protein, with a calculated leucine: thymidine ratio (mol:mol) of about 34. Non-specific labelling of macromolecules other than protein was observed with both the soil slurry and the homogenization-centrifugation method. With the latter, 46.5% of the total incorporation was found in the protein fraction (hot-acid insoluble). The incorporation of leucine was linear with time for at least 4 h for extracted bacteria. Even at 2000 nM, [¹⁴C]-leucine did not saturate incorporation into protein. Isotope dilution plots indicated that with 750 nM leucine, the degree of participation of the labelled substance in protein synthesis was 0.59. With this value, the ratio of leucine:thymidine incorporation into total macromolecules was calculated as 41 for extracted bacteria. On the basis of incorporation into protein (leucine) and incorporation into DNA (thymidine) only, the leucine:thymidine ratio was calculated as 117. The mean turnover time of bacteria at 22°C, calculated using conversion factors from published studies and leucine incorporation into protein of extracted bacteria, was 4.3 days.     

人促红细胞生成素基因和AcGFP1共表达真核表达载体的构建及鉴定

摘要：为构建重组人红细胞生成素（hEPO）真核表达载体，应用PCR及人工合成方法获得除第一内含子的hEPO基因组基因，并将其插入载体pIRES2-AcGFP1，成功构建hEPO基因和AcGFP1共表达载体phEPO-IRES-AcGFP1，然后用脂质体法使该载体转染中国仓鼠卵巢细胞（CHO）及山羊成纤维细胞，于转染后48h在荧263光显微镜下观察到绿色荧光。经G418筛选，在荧光显微镜下发现成簇的绿色荧光细胞，说明重组质粒被成功导入细胞并表达AcGFP1，为鉴定hEPO转染成功与否及阳性细胞筛选提供了方便。     

小流域水文及土壤侵蚀过程模拟方法研究

流域土壤侵蚀动态模拟,需要采用合适的方法对坡面—沟道耦合问题及初始和边界条件进行正确的处理。将流域划分为坡面侵蚀与沟道侵蚀,采用时间空间耦合处理方法,实现了小流域坡—沟侵蚀过程中水流与泥沙输送的面—线耦合及沟道间的线—线连接。给出了模拟流域土壤侵蚀过程的控制微分方程、初始条件、边界条件及坡面向沟道汇水输沙的动态模拟处理方法。得到了较为符合实际的流域土壤侵蚀动态模拟模型。模拟结果与室内实验测量结果的比较表明,模拟精度达到80%以上,说明了动态模拟方法的可行性。     

博斯腾湖湿地边缘带农田土壤重金属的污染风险评价

对新疆博斯腾湖湿地边缘带农田土壤中8种重金属元素(As、Cd、Cr、Cu、Mn、Ni、Pb和Zn)地球化学特征进行分析。采用污染负荷指数(PLI)、潜在生态风险指数(RI)和生态风险预警指数(IER)对农田土壤重金属污染与环境风险进行评价。结果表明:(1)湿地边缘带农田土壤Pb和Zn呈现重度污染,As、Cd、Cr和Ni轻度污染,Cu轻微污染,Mn无污染。土壤As、Cd、Cr、Cu、Ni、Pb和Zn平均含量处于轻微风险水平。Cd是污染程度与生态风险等级最高的重金属元素;(2)湿地边缘带农田土壤PLI平均值为1.43,呈现轻度污染,RI平均值为20.62,呈现轻微生态风险状态,IER的平均值为–4.53,呈现无警态势。湿地边缘带PLI、RI与IER空间分布格局基本一致;(3)湿地边缘带农田土壤Pb与Zn来源主要受到人类活动的影响,Cr、Cu、Mn与Ni来源主要受到土壤地球化学作用的控制,As与Cd受自然因素和人为因素共同影响。     

Quantification of Heavy Metals from A.M.D. Discharged into a Public Water Supply Dam in the Iberian Pyrite Belt (SW Spain) Using Centered Moving Average

In this work, the determination of moving averages is proposed as a method for quantifying metal, arsenic, and sulfate discharges into a water course undergoing acid mine drainage processes which flows into a public water supply dam in the Iberian Pyrite Belt. The analysis of the results obtained by applying moving averages shows that the highest metal and sulfate concentrations occur in October, coinciding with the first rainfall and the sponging of mine dumps, with November and December being the months when the highest contributions to the Andevalo Dam take place. The discharge of acid mine waters with its corresponding metal load into the Andevalo Dam means, for a single hydrological year, more than 6,000 t of sulfates, almost 600 t of iron, and 1 t of As, of special relevance for the hydrochemical quality of the stored waters. When they arrive at the dam, these metals precipitate, since the water pH is near 7, and remain latent in the bottom sediment as long as the chemical makeup of the dam water does not change.     

Assessing the performance of phosphorus-saturated ochre as a fertilizer and its environmental acceptability

Abstract. Flooding of abandoned coal mines often causes discharges of iron-rich drainage water into the environment. Treatment of these discharges results in the formation of ochre (hydrous iron oxides) for which no end-use has been identified. Ochre effectively adsorbs phosphate from solution and thus could be used for remediation of waste waters. The resulting P-enriched ochre could then potentially be recycled as a P fertilizer. Pot and field experiments were set up to assess performance and environmental acceptability of ochre in this role, using grass and barley as test crops, as well as birch and spruce tree seedlings. Soils and plant materials were analysed for total and available P, total metals and pH. Results showed that P-saturated ochre functioned as a slow-release P fertilizer, and in the short term was as effective as conventional P fertilizer in maintaining crop yields. It also raised soil pH, and did not pose any significant problem through introduction of potentially toxic trace metals into the soil.     

不同地貌类型下黄土高原典型县域新增耕地利用变化

土地整治是中国增加耕地数量、确保粮食安全的重要措施。在中国农村人口不断减少、居民膳食结构改变的背景下,土地整治作为推进乡村振兴的重要抓手,其新增耕地利用方向该如何科学确定是亟需研究的问题。该研究以位于黄土高原的延川县为例,利用土地利用、耕地质量等数据,研究了新增耕地在黄土高原典型地貌塬（梁）、坡面、沟道的利用变化,并分析了不同变化类型新增耕地的质量在不同地貌类型的分布,结果表明,延川县新增耕地转变为非耕地的比例为20.69%,林地、草地是新增耕地转变的主要去向,果园种植收益远大于粮食作物种植收益,且果园种植为劳动密集型农业生产活动,需要的劳动时间多,加之农户劳动力数量有限未有更多时间将新增耕地用于粮食生产,使得新增耕地撂荒并转变为了林地、草地。沟道是新增耕地转变为林地的主要分布区域,沟道和塬面（梁）是新增耕地转变为草地的主要分布区域,塬面（梁）是新增耕地转变为果园的主要分布区域,不同地貌类型的水分条件是新增耕地在不同地貌转变为其他土地利用类型时存在差异的主要原因。也反映出,在果园种植收益高的条件下,即使位于沟道的水资源条件较好、质量较高的新增耕地,由于劳动力的限制,也不会被利用以进行粮食作物种植,而是被撂荒并转变为林地,相反塬面（梁）的新增耕地也会被利用为收益更高的果园。未来土地整治新增耕地应根据不同区域地形地貌、水资源等自然条件因地制宜地确定利用方向。     

城市水土保持规划的原理与方法

在论述城市水土保持特点的基础上,从功能分区规划、图则与法则的结合、措施服从城市建设和城市防洪等方面,介绍了城市水土保持规划的原理,对规划中的水土流失调查方法、水土流失诊断方法以及水土保持措施规划方法进行了有益的尝试与探索.     

Use of fiber interface direct mass spectrometry for the determination of volatile flavor release from model food systems.

Described in this paper is a fiber interface direct headspace mass spectrometric system for the real-time measurement of flavor release. The system was optimized for the detection of the garlic aroma volatile, diallyl disulfide, from water. Parameters investigated included interface temperature, flow rate through the fiber, flow rate through the sample vessel, and sample stir rate. The delay time for detection of sample after introduction into the sample vessel was determined as 43 s. The system proved to be reliable and robust with no loss in sensitivity or contamination of the mass spectrometer over a 6 month period. The technique was applied to a homologous series of aliphatic alcohols from C(2) to C(7). Results showed that as polarity decreased with increasing chain length the release of volatile into the headspace was faster and gave a higher maximum intensity. Release of the garlic aroma volatile from different commercial mayonnaise products clearly showed a decrease in the release of diallyl disulfide as fat content increased. These results demonstrate the potential of using this technique as a tool for understanding the complex interactions that occur between flavor compounds and the bulk food matrix.