Tween 80对DDTs污染场地土壤的增溶洗脱效果研究

以苏南某滴滴涕类化合物（DDTs）污染场地土壤为研究对象,进行实验室批量洗脱试验,研究了环境友好型表面活性剂Tween 80对土壤中DDTs的增溶洗脱效果及其影响因素。结果表明,Tween 80显著地增加了DDTs表观溶解度,在临界胶束浓度（CMC）以上对DDTs的增溶曲线呈指数衰减函数关系,DDTs各组分洗脱量顺序为4,4′-DDT〉4,4′-DDD〉2,4′-DDD〉2,4′-DDT。Tween 80的浓度、洗脱次数及土壤吸附作用共同影响其对DDTs的洗脱效果。去离子水能有效去除土壤中残留Tween 80,Tween 80解吸附率最高可达72.66%,大大降低了Tween 80二次污染土壤的风险。Tween 80增溶和去离子水解吸附联合过程对DDTs洗脱效果产生显著的协同作用。10 000 mg·L^-1浓度条件下Tween 80对DDTs的去除率最高为72%,其次为8 000 mg·L^-1 的Tween 80水溶液,去除率为66.72%。采用8 000 mg·L^-1的Tween 80溶液进行土壤洗涤处理,结合其他修复技术,可能会是修复DDTs污染土壤的有效技术方案之一。     

雄性不育松花菜新品种津松80的选育

津松80是以雄性不育系 D－16为母本和以 AM－328为父本配制而成的秋晚熟松花杂种一代，华北地区秋季成熟期80 d 左右，产量比对照品种庆农80增产10.5%~19.3%，花球松散、细嫩、青梗，平均单球质量1.5~2.5 kg，667 m2产量3500~4000 kg。     

预处理及表面活性剂对米曲霉固体发酵产纤维素酶影响的研究

本试验以米曲霉HML366为出发菌株,研究纤维素预处理及化学表面活性剂Tween 80对米曲霉固体发酵产纤维素酶的影响。结果表明:加入不同浓度的Tween 80对预处理过的蔗渣滤纸酶活的影响较为显著,蔗渣经5%氨水、5%乙酸、10%乙酸处理后,添加0.8%Tween 80的滤纸酶活分别可以达到6.6、6.3 U/mL和6.1 U/mL。当Tween 80浓度增加到1.2%浓度时,滤纸酶活有所下降。预处理过的蔗渣及添加Tween 80经发酵后,其发酵液中蛋白质含量较高,酶活较高。     

细胞分裂相关基因Spc25的分子进化研究

采用生物信息学手段分析代表真菌、无脊椎动物和脊椎动物共16种生物Spe25基因的分子进化情况.结果表明,Spc25是一个较为保守的基因,在动物一微管的连接中发挥了重要作用.该研究为进一步研究该基因参与染色体分离和肿瘤发生的作用机理提供资料.     

Late season foliar fertilization of beans with NPKS: Effects of cytokinins,calcium and spray frequency

Abstract

One to two foliar applications of NPKS solutions enhanced yields from 10–40% when applied to pot grown bean plants (Phaseolus vulgaris, var. Bulgarian) during the seed filling period. Further spray applications had progressively more negative effects on yields. Addition of calcium ions or cytokinin to the spray treatments did not give further yield increases. Addition of an organo‐silicone surfactant (L77) to the spray solution gave higher yield increases than those obtained by adding a carbohydrate based surfactant (Tween 80). Percent N P and K contents of the bean seeds were inversely related to yields suggesting that the rate of supply of these minerals to the seeds was not limiting production; the results support the idea that leaf integrity was one of the main factors affected by late season N P K S sprays, and that this in turn affected yields.     

次氯酸钠加吐温80对马铃薯外植体的灭菌比较试验

升汞是灭菌效果非常好的一种灭菌剂,但它是有剧毒的重金属盐灭菌剂,对人畜有极强的毒性,且容易污染环境。为了寻找对马铃薯外植体安全有效的灭菌剂,试验通过对马铃薯外植体,用次氯酸钠溶液与添加吐温80的次氯酸钠溶液不同浓度、不同时间处理后,与升汞处理相比较成苗率、感染率和褐化率。试验结果表明,加2%吐温80的11%次氯酸钠溶液处理30 min,对马铃薯外植体的灭菌效果最好,其成苗率高于0.1%升汞处理后的成苗率;加2%吐温80的13%次氯酸钠溶液处理20 min后的灭菌效果也较好,成苗率略低于0.1%升汞处理后的成苗率。     

X80大口径三通低温断裂韧性试验

油气管道站场用管要求具有较高的低温抗断裂性能,尤其是三通等管件的壁厚较大,尺寸效应显著。为了确定低温服役的X80大口径三通的适用温度和壁厚,通过夏比冲击、落锤撕裂和三点弯曲试验研究了X80大口径三通的低温断裂韧性和尺寸效应,并利用失效评估图技术进行安全评估。结果表明：X80大口径三通具有较好的低温夏比冲击性能,但抵抗低温裂纹长程扩展的落锤撕裂性能较差。试验温度高于-20℃时,随着壁厚增大,DWTT断口剪切面积减小,在20℃、0℃和-10℃试验温度下的50％剪切面积临界壁厚分别为26mm、25mm和22mm。利用三点弯曲试验测得的低温断裂韧度计算的X80三通失效评估点均在安全区域内,而且有一定的安全裕量。（图7,表3,参12）     

基于C8051F80X单片机及PC机的节水灌溉与施肥控制管理系统

基于PC机及C8051 F80X单片机的智能化滴灌及施肥管理系统能够监控不同土壤的湿度,并根据农作物对土壤的不同湿度要求,从而实现适量、适时灌溉的目的.在进行灌溉的同时,把测土配方后的肥料通过输水管道输送到植物根部,科学合理的进行水肥供给.单片机和PC机是智能化滴灌及控制施肥的核心部分,对土壤灌水量与湿度的关系、智能滴灌技术、控制系统的硬软件等部分进行了探讨与研究,同时根据不同的作物对各类肥料有不同的需求率和利用率,对不同的植物采用不同的施肥方式,提高肥料利用率.把灌溉和施肥结合起来,可以完成对作物生长期各个阶段的肥料及水分需求进行统计,形成农业专家数据库,真正作到科技兴农.     

Genotypic diversity in Babesia bovis field isolates and vaccine strains from South Africa

Genotypic diversity in Babesia bovis (cause of Asiatic redwater in cattle) vaccine strains and field isolates from South Africa were investigated using the Bv80 gene as well as microsatellites. The S11 vaccine strain possessed both A and B alleles of the Bv80 gene, as well as genotypic diversity within each allele type as defined by repeat variation resulting in different amplicon sizes. Rapid serial passage of vaccine strain from passage S10 to S24 resulted in loss of genotypic diversity that yielded a single allele A genotype with an amplicon size of 558 bp. This suggested that clonal selection occurred during rapid passaging. Extensive genotypic diversity exists in 44 field isolates characterized with both Bv80 A and B alleles, but can be readily distinguished from the S24 vaccine strain using either the Bv80 allele specific PCR assays or using multi-locus micro-satellite typing. This indicated that no recent documented clinical cases of Asiatic redwater were caused by the reversion to virulence of the current vaccine strain.