Mechanical properties of semi-interpenetrating polymer network hydrogels based on poly(2-hydroxyethyl methacrylate) copolymer and chitosan     

Young A. Han  Eun Mi Lee  Byung Chul Ji 《Fibers and Polymers》2008,9(4):393-399

Semi-interpenetrating polymeric network (semi-IPN) hydrogels based on poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(2-hydroxyethyl methacrylate-co-sodium methacrylate) [P(HEMA-co-SMA)], and chitosan with different molecular weights were prepared by crosslinking with ethylene glycol dimethacrylate (EGDMA) and poly(ethylene glycol) diacrylate (PEGDA) and their gelation time, water content, mechanical properties, and morphology were investigated. In consideration of the influence of the molecular weight of chitosan, there is no big difference in the water content, while tensile properties and compressive modulus increased as the molecular weight of chitosan increased. The water content increased and tensile properties and compressive modulus decreased with increasing SMA concentration. Considering the effect of the crosslinking agent, PEGDA had higher water content and lower tensile and compressive moduli than EGDMA. It is suggested that PHEMA/chitosan and P(HEMA-co-SMA)/chitosan semi-IPN hydrogels with different structures and physical properties can be prepared depending on the molecular weight of chitosan, the copolymerization with SMA, and the crosslinking agent type.  相似文献   

氮磷钾配施对玛咖产量和品质的影响及肥料效应   总被引：1，自引：0，他引：1  

李浩  徐瑞  施辉能  刘春兰  龙光强  田洋  范伟 《核农学报》2021,35(10):2404-2412

为探究玛咖优质高效种植的合理施肥量和施肥配方,本研究采用“3414”随机区组设计开展田间小区试验,测定玛咖植株农艺性状、产量和品质性状等指标,通过拟合肥料效应函数方程并结合品质性状确定氮、磷、钾施肥量。结果表明,氮磷钾的合理配施能不同程度促进玛咖地上部和地下部的生长,提高其产量和品质,其中N₂P₂K₂(N:P₂O₅:K₂O=8:6:8)的玛咖地下部农艺性状、产量、玛咖烯、芥子油苷和灰分含量最高;氮、磷、钾3种元素对玛咖产量存在明显的互作效应,表现为N₂P₂K₂施肥水平有利于氮、磷、钾肥效的发挥;通过田间小区试验得出玛咖最高理论产量为9 346.95 kg·hm^-2。综合肥料三因素、产量和品质分析得出,N₂P₂K₂的玛咖产量最高、品质最好。最高产量的氮磷钾施肥用量为N:P₂O₅:K₂O=120.71:92.16:144.22 kg·hm^-2,产量达到8 577.35 kg·hm^-2;经济最佳产量的氮磷钾施肥用量为N:P₂O₅:K₂O=120.58:91.76:143.35 kg·hm^-2,产量达到8 577.29 kg·hm^-2。本研究结果为指导和规范玛咖的施肥技术提供了理论依据。  相似文献   

Sulfonylurea-resistant biotypes of Monochoria vaginalis generate higher ultraweak photon emissions than the susceptible ones     

Hidehiro Inagaki  Toshiyuki Imaizumi  Guang-Xi Wang  Tohru Tominaga  Kimihiko Kato  Hiroyuki Iyozumi  Hideki Nukui 《Pesticide biochemistry and physiology》2009,95(3):117-120

All living organisms spontaneously generate ultraweak photon emissions, which originate from biochemical reactions in cells. Current research uses the ultraweak photon emission from organisms as a novel indicator in nondestructive analyses of an organisms living state. This study indicates that ultraweak photon emissions from Monochoria vaginalis are different between resistant biotypes (R) to sulfonylurea (SU) and susceptible biotypes (S). In SU-R biotypes, distinct increases in photon emissions were observed, but there was little increase in SU-S biotypes. In addition, photon emissions from the resistant biotypes of M. vaginalis were suppressed by treatment with P450 inhibitors. This suggests that cytochrome P450 monooxygenase, which plays a crucial role in the metabolic detoxification of SUs, could be associated with the generation of ultraweak photon emissions. Ultraweak photon emissions have a potential use in a novel diagnosis system as an indicator in a nondestructive testing of weeds resistant to SUs.  相似文献   

Effects of the herbicide LASSO MTX (alachlor 42% W/V) on biometric parameters and liver biomarkers in the common carp (Cyprinus carpio)     

Premysl Mikula  Jana Blahova  Marcela Havelkova  Martin Hulak 《Pesticide biochemistry and physiology》2009,93(1):13-89

The aim of the study was to evaluate the effect of subchronic exposure to the herbicide LASSO MTX (alachlor 42% W/V) on biometric parameters and important liver biomarkers in the common carp (Cyprinus carpio). One year old fish were exposed for 28 days to LASSO MTX added to the tank water at concentrations of 240 and 2400 μg L⁻¹. The exposure did not affect fish biometric parameters. Glutathione-S-tranferase (GST) activity in liver (hepatopancreas) remained unchanged in exposed fish when compared to controls. However, significant induction of total cytochrome P 450 (CYP 450), ethoxyresorufin-O-deethylase (EROD) activity and elevated glutathione (GSH) in liver of exposed fish were detected.  相似文献   

茶树黄酮合成酶Ⅱ基因全长cDNA序列的克隆和实时荧光定量PCR检测     

乔小燕  马春雷  陈亮 《茶叶科学》2009,29(5)

利用RT-PCR和RACE技术,克隆得到茶叶中合成黄酮类化合物的关键酶基因—黄酮合成酶Ⅱ,该基因属于细胞色素P450家族,在GenBank登录号为FJ169499。黄酮合成酶ⅡcDNA全长序列1824bp,其中1605bp为编码区,编码534个氨基酸,分子量为60.4kD。通过SYBRGreenI实时荧光定量PCR检测,发现黄酮合成酶Ⅱ在茶树一芽二叶春梢、当季成熟叶、花瓣、花蕊、种子中都有表达,成熟叶的表达量显著高于其他四种组织。  相似文献   

蔗园土壤速效磷丰缺临界值的研究   总被引：2，自引：0，他引：2  

谢如林  黄献华  谭宏伟  周柳强  黄美福  黄金生  董文斌 《热带作物学报》2009,30(3):304-308

以赤红壤为研究对象,通过甘蔗盆栽试验,利用Olsen和Mehlich3方法,研究甘蔗土壤速效磷的临界值及丰缺情况.结果表明:当土壤Olsen-P含量低于13.7 mg/kg或Mehlich3-P含量低于15.4 mg/kg时,甘蔗植株的生长量随土壤速效磷含量的增加而显著增加.甘蔗地上部干物质相对产量与土壤速效磷含量的关系可以用一元二次响应方程来拟合,Olsen-P的响应方程为:y=0.319 8x2+12.263x-15.471,决定系数R=0.9767**;Mehlich3-P的响应方程为:y=0.236 6x2+10.532x-12.794,R=0.975 8**.以最高产量的95%作为临界产量,计算得到蔗园土壤Olsen-P和Mehlich 3-P丰缺临界值分别为14.5、16.0 mg/kg.  相似文献   

山东省多主棒孢对三种常用杀菌剂的敏感性监测及对氟吡菌酰胺的抗性     

李桂香  李秀环  郝新昌  李智文  刘峰  刘西莉 《中国农业科学》2022,55(7):1359-1370

[目的]由多主棒孢(Corynespora cassiicola)引起的黄瓜靶斑病是世界公认的黄瓜三大病害之一,严重影响着黄瓜的产量和品质.随着防治药剂的连续使用,其抗药性问题日益突出.本研究旨在明确山东省多主棒孢对常用杀菌剂的抗性情况,为黄瓜靶斑病的药剂防治提供理论依据,同时筛选高效混配药剂为多主棒孢的抗药性治理提供...  相似文献   

氮磷钾配施对水稻产量的影响研究   总被引：1，自引：0，他引：1  

陈竹峰  杨波  邓斯聪 《现代农业科学》2008,(10):17-18

研究了氮、磷、钾化肥配合施用对水稻产量的影响,结果表明:在磷、钾养分相等的条件下,当氮肥的用量超过21.0 kg/667 cm2时,水稻的增产效果不显著;水稻氮肥的用量范围为9.0~21.0 kgkg/667m2。氮、磷、钾化肥的合理施用对水稻产量及其构成因子有非常显著的影响。  相似文献   

磨盘山水库总氮、总磷变化倾向的灰预测     

刘春颖  翟平阳  孔德勇  鄂勇 《东北农业大学学报》2008,39(11)

氮和磷是磨盘山水库水体非点源污染最主要的污染物。根据汇入水库的支流水体中TN、TP的历年实际监测结果,可以模拟虚构历年水库水体中TN、TP的浓度,并以此作为灰预测所需数据,运用灰色模型预测水库水质TN、TP的变化倾向。经4种检验证明,建立的GM(1,1)模型精度较高,预测结果与实际监测浓度接近。从利用单一的GM(1,1)模型和GM(1,1)模型群预测比较可以看出,以模型群统计平均值作为最终预测值,使得预测精度更加准确,提高了预测结果的可信度,从而避免由于信息不稳定性在单一灰色模型所造成的缺陷。  相似文献   

施用不同配比N、P、K肥延长沟叶结缕草绿期的试验研究     

冯锡振  王加真 《安徽农业科学》2008,36(12):4970-4972

[目的]实现沟叶结缕草在亚热带地区的四季常青。[方法]在9月26日1、0月11日1、0月26日对沟叶结缕草施用不同配比的N、P、K肥,考察其生长指标。[结果]施肥能增加沟叶结缕草植株高度,10月11日施肥效果好。9~10月施N、NP、NK、NPK肥可增加草坪绿叶数,增幅达73%~137%。施用不同配比N、P、K肥可增加枯叶生物量,早施肥处理的枯叶生物量比迟施肥处理多。随着施肥时间的推迟,各处理绿叶生物量呈减少趋势。地上部绿枯比接近1.0时施肥延长草坪绿期的效果最好。施肥处理草坪图象的G值都增大,10月11日施肥处理的最大。[结论]10月上旬是沟叶结缕草施肥的最佳时期,同时施N、P、K肥效果最好。  相似文献