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1.
阐述了可持续发展和可持续植物保护的基本理念,介绍了有机农业病虫害防治的主要措施,论述了有机农业是可持续发展的农业生产方式,全面分析了有机农业植物保护对农业生态可持续发展的影响、作用,主要涉及:人、社会、经济、环境的协调发展;生态平衡和物种多样;综合治理和操作规范等。  相似文献   

2.
基于对建筑垃圾管理政策研究的基础上,着重考察三种环境经济政策(填埋收税、资源化补贴和绿色采购)对建筑垃圾资源化的影响;根据不同环境经济政策下垃圾资源化参与主体的成本和效益,选择利于建立建筑垃圾资源化长效机制的环境经济政策,为政府主管部门制定政策提供参考.  相似文献   

3.
在研究机载蒸发循环制冷系统工作原理的基础上,介绍了一种在MATLAB/SIMULINK环境下对蒸发循环制冷系统的优化方法.通过该方法得出了影响蒸发循环制冷系统性能的主要参数,并分析了各参数对制冷系统性能的影响程度,得出了不同影响 因素下的变化规律.仿真结果可对机载蒸发循环制冷系统的理论分析和设计提供参考.  相似文献   

4.
Fe^3+对脆杆藻增殖的影响   总被引:1,自引:0,他引:1  
采用AGP实验的方法,研究了Fe3 的不同质量浓度对脆杆藻(Fragilaria sp.)细胞增殖的影响.对光密度值和叶绿素a的测定结果显示:Fe3浓度<50 μg/L,脆杆藻的细胞增殖受到抑制.Fe3浓度在50~500μg/L之间时,脆杆藻的细胞增殖明显.Fe3浓度达到1000μg/L时,实验前6 d,细胞密度基本无增长,在7~14 d脆杆藻已适应该浓度,细胞进行分裂,密度增长.第15 d后细胞分裂又处于停止状态.说明Fe3浓度>1000μg/L对脆杆藻细胞的代谢、分裂产生了一定程度的抑制作用.适宜的铁浓度对水体富营养化有促进作用.  相似文献   

5.
目的探讨沉默α-烯醇化酶(ENO1)基因对宫颈癌SiHa细胞化疗药物敏感性的影响。方法采用慢病毒介导的RNA干扰技术,建立ENO1基因稳定沉默SiHa细胞系;通过western blot方法验证ENO1的表达水平;ENO1基因沉默后运用细胞增殖实验检测其对细胞增殖能力的影响;采用MTT的方法评价沉默ENO1基因的SiHa细胞对紫杉醇和顺铂的敏感性。结果成功建立ENO1基因沉默的SiHa细胞系;沉默ENO1基因表达后,SiHa细胞增殖能力下降;沉默ENO1基因能够增强SiHa细胞的药物敏感性。结论:ENO1能够影响宫颈癌细胞的增殖及其对化疗药物的敏感性。  相似文献   

6.
目的观察手性旋光异构体德氮吡格(TNBG)对6株人体肿瘤细胞增殖的影响,初步探讨其抗肿瘤作用机制。方法运用MTT法检测手性TNBG对6株肿瘤细胞生长抑制情况;油红O染色法观察QGY-7701细胞中脂质聚集情况;流式细胞仪检测手性TNBG对人肝癌细胞株QGY-7701细胞周期分布和凋亡影响。结果手性TNBG能不同程度抑制肿瘤细胞增殖,且呈剂量依赖性;油红O染色提取显示QGY-7701细胞内脂质量与给药剂量呈正相关;流式细胞仪检测到有s期细胞增加,并且手性TNBG还能诱导QGY-7701细胞发生凋亡。结论手性TNBG在体外具有良好的抗肿瘤活性,其抗肿瘤作用机制可能是通过促使肿瘤细胞产生脂质聚集,抑制肿瘤细胞增殖、诱导其凋亡从而达到抗肿瘤效应。总体看(+)TNBG体外抗肿瘤活性比(-)TNBG更强。  相似文献   

7.
交叉学科研究推动了生物无机化学学科的发展   总被引:2,自引:0,他引:2  
本文分为七部分,第一部分对生物无机化学学科发展进行历史回顾;第二部分从回顾史实中用实例表明生物无机化学的研究始终瞄准金属离子和生物配体控制生命过程中的化学问题;第三部分是介绍当今国际上研究核酸领域的争论焦点;第四部分是报导我们设计和合成了作为人工核酸酶的一系列新的配体以及许多不同金属的功能配合物;第五部分是讨论用动力学、热力学和DFT计算方法研究配合物和DNA相互作用的键合机制以及十多种影响因素;第六部分进一步报导配合物的生物功能和它们的应用探索,最后一部分提出在核酸领域的某些新的发展方向和途径。我们进一步提出了配合物的结构与DNA的作用机制以及它们的生物功能之间的规律性。通过配合物的结构改变去调控和改变配合物对DNA键合性质和生物功能。  相似文献   

8.
科技进步使21世纪下半叶世界农产品的增长首次超过了人口的增长;但90年代农业发达国家突然刮起一阵对高产农业的批判风,指责高产农业是造成食品污染,水土流失、生物灭亡、环境恶化之根源,主张实施不用或少用化肥、农药“低投入农业”。事出有因,查无实据,看法迥异,后果堪虞。对高产农业批判造成农业思想之混乱;在中国农业界也引起不同的反响。中国人多地少,人均资源不多,必须坚定不移地走一条集约化高产、优质、高产农  相似文献   

9.
目的 观察中药复方解聚复肾宁(JJFSN)对高耱环境下大鼠肾小球系膜细胞(mesangial cell,MC)增殖和细胞周期的影响.方法 以高糖诱导MC增殖,采用血清药理学方法制备不同浓度JJFSN舍药血清,加入培养液中,用MTT法检测细胞增殖,流式细胞技术检测细胞周期.结果 MTT显示:JJFSN含药血清可抑制高糖诱导的MC过度增殖(P<0.05),并且这种作用具有药物剂量和时间依赖关系.流式细胞技术分析表明:JJFSN可逆转高糖对细胞周期的影响,使G0/G1期细胞比例增加,S期细胞比例下降(P<0.05) 在高浓度时还能促进MC细胞凋亡.结论 JJFSN可以通过调节细胞周期,促进细胞凋亡,从而抑制高糖诱导的MC过度增殖,这可能是JJFSN防治DN早期的作用杌理.  相似文献   

10.
世界氢能与氢经济的发展概况及不同认识   总被引:1,自引:0,他引:1  
介绍了世界主要发达国家和地区的氢能与氢经济发展近况,讨论了关于氢经济发展与环境的关系、氢能的利用效率、使用安全性以及成本费用方面的不同看法,提出氢经济发展还存在诸多问题需要各方共同努力解决。  相似文献   

11.
Growth hormone signal transduction   总被引:1,自引:0,他引:1  
Growth hormone (GH) promotes animal growth by stimulating bone and cartilage cell proliferation, and influences carbohydrate and lipid metabolism. Some of these effects are brought about indirectly via somatomedin induction in hepatocytes, others by acting directly on the target cells. In either case, GH first binds to specific receptors on cells to trigger a sequence of biochemical events culminating in a biological response. Recently much has been learnt about the molecular structure of GH receptor, its binding to ligand, and the ensuing signal transduction events.  相似文献   

12.
Summary Prenatal development, characterized by intensive cell proliferation, cell differentiation and cell migration, shows a high radiosensitivity. Therefore, radiation exposure of embryos and fetuses is of great concern for radiological protection and human health. Irradiation during gestation can cause death, growth disorders, malformations, functional impairment and malignant diseases in childhood. These effects are strongly dependent on the developmental stage at exposure and on the radiation dose. The first trimester of pregnancy is regarded as the period with the highest risk for malformation and cancer induction. The developing nervous system shows a special susceptibility to ionizing radiation over a long period and is therefore of great significance for risk estimation. Knowledge about radiation effects on prenatal development has been derived from animal experimentation and from the exposure of human embryos. There is evidence that doses between 1 and 10 cGy may lead to developmental anomalies and that the radiation response can be modified by additional factors.  相似文献   

13.
C Michel 《Experientia》1989,45(1):69-77
Prenatal development, characterized by intensive cell proliferation, cell differentiation and cell migration, shows a high radiosensitivity. Therefore, radiation exposure of embryos and fetuses is of great concern for radiological protection and human health. Irradiation during gestation can cause death, growth disorders, malformations, functional impairment and malignant diseases in childhood. These effects are strongly dependent on the developmental stage at exposure and on the radiation dose. The first trimester of pregnancy is regarded as the period with the highest risk for malformation and cancer induction. The developing nervous system shows a special susceptibility to ionizing radiation over a long period and is therefore of great significance for risk estimation. Knowledge about radiation effects on prenatal development has been derived from animal experimentation and from the exposure of human embryos. There is evidence that doses between 1 and 10 cGy may lead to developmental anomalies and that the radiation response can be modified by additional factors.  相似文献   

14.
Peptides and epithelial growth regulation   总被引:1,自引:0,他引:1  
There is now considerable evidence implicating several peptides in the control of gastrointestinal epithelial cell proliferation and cell renewal. While some of these may act directly, many may be involved in regulating the powerful trophic effects of the intake and digestion of food on the gut epithelium. Several peptides have been associated with the regulation of intestinal cell proliferation. There is little doubt that gastrin is trophic to the stomach, but, its role in the rest of the gastrointestinal tract is debatable. Enteroglucagon has often been associated with increased intestinal epithelial proliferation, but at the moment all the evidence for this is circumstantial. The effects of peptide YY and bombesin warrant further study. The availability of recombinant epidermal growth factor (EGF) has recently enabled us to demonstrate a powerful trophic response to infused EGF throughout the gastrointestinal tract. The increasing availability of peptides will eventually allow the rigorous in vivo evaluation of the trophic role of these potentially very important peptides.  相似文献   

15.
Summary There is now considerable evidence implicating several peptides in the control of gastrointestinal epithelial cell proliferation and cell renewal. While some of these may act directly, many may be involved in regulating the powerful trophic effects of the intake and digestion of foold on the gut epithelium.—Several peptides have been associated with the regulation of intestinal cell proliferation. There is little doubt that gastrin is trophic to the stomach, but, its role in the rest of the gastrointestinal tract is debatable. Enteroglucagon has often been associated with increased intestinal epithelial proliferation, but at the moment all the evidence for this is circumstantial. The effects of peptide YY and bombesin warrant further study. The availability of recombinant epidermal growth factor (EGF) has recently enabled us to demonstrate a powerful trophic response to infused EGF throughout the gastrointestinal tract. The increasing availability of peptides will eventually allow the rigorous in vivo evaluation of the trophic role of these potentially very important peptides.  相似文献   

16.
Y Kaneko  Y Imai  F Matsuzaki  Y Endo  T Oda 《Experientia》1979,35(12):1060-1061
Epidermal growth factor stimulated both [3H]thymidine uptake and proliferation of rat AH66 hepatoma cells. However, the increase in cell number was not accompanied by a proportional increase in the levels of alpha-fetoprotein of the culture media. The effects of EGF on the cell proliferation were antagonized by N6,O2'-dibutyryl cAMP.  相似文献   

17.
The present study identified aloe-emodin (AE, a hydroxyanthraquinone from Aloe vera and other plants) as a new anti-angiogenic compound with inhibitory effects in an in vivo angiogenesis assay and evaluates its effects on specific key steps of the angiogenic process. AE inhibits endothelial cell proliferation, but this effect is not cell specific, since AE also inhibits tumor cell proliferation. Cell migration and invasion are not remarkably affected by AE. On the other hand, AE has different effects on endothelial and tumor cell gelatinases. Two main targets of the pharmacological action of AE as an anti-angiogenic compound seem to be urokinase secretion and tubule formation of endothelial cells. Finally, AE produces a remarkable photocytotoxic effect on tumor cells. Taken together, our data indicate that AE can behave both as an anti-tumor and an anti-angiogenic compound and suggest that AE could be a candidate drug for photodynamic therapy. Received 7 September 2006; received after revision 17 October 2006; accepted 31 October 2006  相似文献   

18.
19.
The cystic phenotype in autosomal dominant polycystic kidney disease is characterized by a profound dysfunction of many cellular signaling patterns, ultimately leading to an increase in both cell proliferation and apoptotic cell death. Disturbance of normal cellular Ca2+ signaling seems to be a primary event and is clearly involved in many pathways that may lead to both types of cellular responses. In this review, we summarize the current knowledge about the molecular and functional interactions between polycystins and multiple components of the cellular Ca2+-signaling machinery. In addition, we discuss the relevant downstream responses of the changed Ca2+ signaling that ultimately lead to increased proliferation and increased apoptosis as observed in many cystic cell types.  相似文献   

20.
As a member of tumor suppressor p53 family, p63, a gene encoding versatile protein variant, has been documented to correlate with cancer formation and progression, though it is rarely mutated in cancer patients. However, it has long been controversial on whether p63 is an oncogene or a tumor suppressor. Here, we comprehensively reviewed reports on roles of p63 in development, tumorigenesis and tumor progression. According to data from molecular cell biology, genetic models and clinic research, we conclude that p63 may act as either an oncogene or a tumor suppressor gene in different scenarios: TA isoforms of p63 gene are generally tumor-suppressive through repressing cell proliferation, survival and metastasis; ΔN isoforms, however, may initiate tumorigenesis via promoting cell proliferation and survival, but inhibit tumor metastasis and progression; effects of p63 on tumor formation and progression depend on the context of the whole p53 family, and either amplification or loss of p63 gene locus can break the balance to cause tumorigenesis.  相似文献   

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