Synthesis and properties of Nylon 4/5 copolymers for hydrophilic fibers

Nylon 4, which can be synthesized by anionic ring-opening polymerization, has good mechanical properties and a very high affinity for water owing to its high polarity. On the other hand, despite its high melting temperature, the polymer has not been commercialized because of its low thermal stability. In this study, copolymerization of 2-pyrrolidone (C4) with 2-piperidone (C5) was performed to reduce the melting temperature of Nylon 4 homopolymer. The copolymerization reaction was controlled by changing the comonomer content, catalyst content, temperature, initiator content, and reaction time. The Nylon copolymers were characterized by ¹H-nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The hydrophilic properties of Nylon 4 and its copolymers were evaluated by surface free energy analysis and moisture regain measurement. The intrinsic viscosity and polymerization yield of Nylon 4 increased with increasing catalyst concentration until 5 mole% and decreased with further increases in catalyst loading. The proton NMR spectrum revealed the composition of the Nylon 4/5 copolymer to be 62.5 % C4 moiety at a 5:5 comonomer feed ratio. The melting temperature of the Nylon 4/5 copolymers decreased considerably according to the composition. The moisture regain of the Nylon 4/5 copolymer was higher than 6.4 % even at 77.3 % C4 in composition.     

6个典型四川小麦品种不同生育期抗条锈性研究

试验于2011～2012年通过大田高感品种自然诱发对近年四川小麦生产上具有较大影响力的6个代表性小麦品种进行了不同生育期抗条锈性研究.经方差分析结果表明,6个小麦品种在不同生育期对条锈菌的反应型有极显著性差异(p＜0.001),病情指数有显著差异(0.01＜p＜0.05).多重比较结果显示,6个品种反应型在不同生育期出现先升后降的趋势,而川育23反应型逐渐降低,川农26反应型逐渐升高;病情指数研究表明,川农26病情指数逐渐增高,川育23病情指数逐渐降低,其他品种病情指数变化不明显.结合品种的农艺性状的比较,绵杂168、川麦42、西科麦4号、内麦9号抗条锈性优良,川农26抗条锈性差,应逐渐淘汰,川育23可能携带有高温抗锈基因将有待于进一步研究.     

Surface coating as a key parameter in engineering neuronal network structures in vitro

By quantitatively comparing a variety of macromolecular surface coating agents, we discovered that surface coating strongly modulates the adhesion and morphogenesis of primary hippocampal neurons and serves as a switch of somata clustering and neurite fasciculation in vitro. The kinetics of neuronal adhesion on poly-lysine-coated surfaces is much faster than that on laminin and Matrigel-coated surfaces, and the distribution of adhesion is more homogenous on poly-lysine. Matrigel and laminin, on the other hand, facilitate neuritogenesis more than poly-lysine does. Eventually, on Matrigel-coated surfaces of self-assembled monolayers, neurons tend to undergo somata clustering and neurite fasciculation. By replacing coating proteins with cerebral astrocytes, and patterning neurons on astrocytes through self-assembled monolayers, microfluidics and micro-contact printing, we found that astrocyte promotes soma adhesion and astrocyte processes guide neurites. There, astrocytes could be a versatile substrate in engineering neuronal networks in vitro. Besides, quantitative measurements of cellular responses on various coatings would be valuable information for the neurobiology community in the choice of the most appropriate coating strategy.     

时域反射仪的测量精度及其与中子仪的对比

野外和室内试验表明，用６０５０Ⅺ型时域反射仪（ＴＤＲ）测定土壤含水率与中子仪法相比，速度快，精度高；还发现随着导棒长度的增大，ＴＤＲ与烘干法测定结果的偏差有所增大，文中给出了５种导棒长度的校正公式     

Prickly paddy melon (Cucumis myriocarpus) poisoning of cattle

Twenty-six Hereford heifers died after eating mostly ripe fruit of Cucumis myriocarpus growing in a fallowed cultivation paddock. Four affected cattle were dehydrated and apparently had abdominal pain. Necropsy of three revealed intense congestion with haemorrhage of the alimentary tract, numerous C. myriocarpus seeds in ruminal contents, pulmonary congestion and oedema and, in two, swollen livers. Midzonal swelling and vacuolation of hepatocytes occurred in these two. C. myriocarpus fruit (83% by weight ripe) were dosed to two calves at 60 g wet weight/kg live weight. Both collapsed with tachycardia and dyspnoea and died within 6 h. Their packed cell volumes just before death had increased to 0.7. They had hydropic degeneration and necrosis of the ruminal mucosa, intense congestion and oedema of the rumen, abomasum and intestines, swollen and vacuolated hepatocytes and foci of myocardial degeneration and necrosis. Two other calves were dosed daily with 20 g fruit/kg for three days, then 40 g/kg for three days. One calf received a further 40 g/kg next day. Both calves developed persistent diarrhoea and neutrophilia, and their plasma gamma glutamyltransferase and bilirubin concentrations increased. Necropsy revealed necrosis and oedema of the rumen and swollen degenerate hepatocytes.     

两种氮水平下CO2浓度升高对冬小麦生长和氮磷浓度的影响

预计到 2 1世纪末期大气CO2 浓度将会比目前水平增加 1倍 ,约 70 0 μmolmol- 1 左右。因此CO2 浓度升高对作物的影响研究十分重要。本文探讨在两种氮 (N)水平下 ,CO2 浓度升高对冬小麦 (TriticumaestivumL cv Xinong 872 7)生长和地上部N、磷 (P)浓度的影响及原因。试验设 3 5 0 μmolmol- 1 和 70 0 μmolmol- 1 两种CO2 浓度水平和 45kghm- 2 和 90kghm- 2 两种N肥施用水平。结果表明 ,CO2 浓度升高 ,冬小麦株高和叶面积指数 (LAI)均增加 ,净同化率 (NAR)值增加 ,叶面积比率 (LAR)下降 ,比叶重 (SLW )不增加。高CO2 浓度对相对生长率 (RGR)的影响因施N水平而异 ,低N时RGR不增加 ,高N时明显增加。CO2 浓度增加 ,小麦抽穗提早 7～ 8d ,叶鞘、茎杆和地上部干物重提高 ,叶片、叶鞘和茎杆N、P浓度降低 ,但叶片、叶鞘和茎杆N、P吸收量增加均不明显。CO2 浓度升高 ,氮磷利用效率 (NUE和PUE)提高 ,而对相对氮磷累积速率 (RNAR和RPAR)影响不大。高CO2 浓度冬小麦体内N、P浓度下降是由于稀释效应以及NUE和PUE提高之故。     

TCD燃烧系统对柴油机燃烧和排放性能改善效果的试验研究

为探究道依茨TCD2015柴油机上配备的导流燃烧系统(简称TCD燃烧系统,T表示涡轮增压器,Turbocharger,C表示进气中冷,Charge air cooling,D为柴油颗粒捕集器,Diesel particle filter)对改善柴油机燃烧性能和降低污染物排放的效果,采用单缸机试验对TCD燃烧系统在不同转...     

黄土区不同下垫面农田降雨入渗及产流关系的数值模拟

在野外试验的基础上，建立了二维农田降雨入渗及产流关系的数学模型，并用中国科学院长武县王东沟农业生态站不同下垫面径流小区实测土壤含水率及产流资料对该模型进行验证。结果显示：该模型对降雨过程中土壤入渗、产流以及雨后蒸发条件下土壤水分的模拟都有很高的精度，可以用于黄土区降雨入渗及产流关系的模拟。     

美国白蛾新天敌—蠋敌捕食能力的初步观察

首次报道美国白蛾Hyphantria cunea(Drury)的一种捕食性天敌——蠋敌Arma chinensis(Fallou),简述了蠋敌的生物学特性。在商河县,蠋敌在美国白蛾幼虫网幕枝中的分布率为2.33%～17.86%;记述了蠋敌的捕食习性和规律,经室内饲养,统计出各龄若虫和成虫的捕食量,从若虫到成虫,最大捕食量为2头3龄、7头4龄、5头5龄、23头6龄共37头白蛾幼虫;最小取食量为4头2龄、8头3龄、1头4龄、1头5龄、2头6龄共16头白蛾幼虫;分析并指出蠋敌对美国白蛾具有较强的控制能力,是自然界中影响美国白蛾种群密度的重要因子。     

Immunophenotypic and histological characterisation of 109 cases of feline lymphosarcoma

OBJECTIVE: To determine and analyse the immunophenotype and histological appearance of naturally occurring cases of lymphosarcoma in Australian cats. DESIGN: A prospective multi-institutional study of naturally occurring feline lymphosarcoma. METHODS: One hundred and eighteen cats were referred for diagnosis and/or management of suspected lymphosarcoma. Tissue samples for histopathological analysis and immunophenotyping were collected as biopsies or at necropsy from 109 cases. Histological classification of the neoplasms followed the Working Formulation Classification System. Four multi-species cross-reactive antibodies were used to classify tumours as having a B or T cell phenotype. RESULTS: Seventy-six (70%) cases were B cell tumours and 28 (26%) were T cell tumours. The remaining 5 (4%) specimens failed to stain with the four antibodies. Histologically, 11 (10%) cases were classified as low-grade, 72 (66%) were medium-grade and 26 (24%) were high-grade tumours. There were no significant associations between age and either histological grade or immunophenotype. Mediastinal and leukaemic cases were significantly more likely to be T cell tumours (P < 0.001 and P < 0.001, respectively). CONCLUSIONS: In contrast to previously documented studies in the cat, the majority of cases of lymphosarcoma were of B cell phenotype and intermediate histological grade. Based on our data, the histological phenotype of lymphosarcoma is unlikely to predict immunotype, nor are cases of certain immunotypes likely to be of specific histological subtype. Considered in relation to previous reports, the findings suggest that epidemiological factors operating in these cats to produce lymphosarcoma may be different to those operating in North American and UK cat populations.