Somatic activation of the K-ras oncogene causes early onset lung cancer in mice

About 30% of human tumours carry ras gene mutations. Of the three genes in this family (composed of K-ras, N-ras and H-ras), K-ras is the most frequently mutated member in human tumours, including adenocarcinomas of the pancreas ( approximately 70-90% incidence), colon ( approximately 50%) and lung ( approximately 25-50%). To construct mouse tumour models involving K-ras, we used a new gene targeting procedure to create mouse strains carrying oncogenic alleles of K-ras that can be activated only on a spontaneous recombination event in the whole animal. Here we show that mice carrying these mutations were highly predisposed to a range of tumour types, predominantly early onset lung cancer. This model was further characterized by examining the effects of germline mutations in the tumour suppressor gene p53, which is known to be mutated along with K-ras in human tumours. This approach has several advantages over traditional transgenic strategies, including that it more closely recapitulates spontaneous oncogene activation as seen in human cancers.     

试论清代地方官大计展限问题

清代每三年对地方官举行一次大计考核。地方大计或因督抚、布政使及基层州县官人事变动,或因地方战乱,常要展限,并补行大计。大计展限执行中,由于偏重形式问题,并不能真正发挥计典黜幽陟明的作用。     

足球运动中延缓疲劳产生的方法

应用运动生理学、运动生物化学等知识,根据足球运动中疲劳产生的机理,提出了一些延缓疲劳产生的有效方法．     

小鼠肥胖介导的肠道炎症反应与肠癌发病关系研究

探讨TNF-α激发Wnt/β-catenin信号通路介导的结肠癌形成与发展机制,以及姜黄素作为肥胖预防药物的抗炎抗癌的作用。通过建立高脂饮食诱导的肥胖模型,以及氧化偶氮甲烷(azoxymethane,AOM)诱导的结肠癌模型;并结合天然药物姜黄素治疗结肠炎和癌症,采用RT-PCR、Western blot等技术检测肥胖相关炎症因子IFN-γ、TNF-α、IL-6、IL-10以及Wnt/β-catenin信号通路中p-GSK-3β和β-catenin的表达情况,采用HE染色法观察各组结肠组织病理结构。实验结果表明:肥胖组炎症状态比较明显,与结肠癌模型组各个指标都接近。姜黄素组有缓解肥胖引起的炎症以及氧化偶氮甲烷引起的结肠组织损伤。因此,肥胖诱导的炎症,可能通过TNF-α激发Wnt/β-catenin信号通路,导致p-GSK-3β和β-catenin的积累,从而诱发结肠癌。     

新型铜-锌复合延时保险丝的研制

本文对套管拉拔法制备双金属复合丝的工艺过程作了较为详尽的研究－ 由此制备的Ｃｕ 包Ｚｎ及Ｃｕ 包Ｚｎ － ０ ．５ｗｔ％ Ａｌ 复合丝的延时性能达到了国际ＩＥＣ 标准, 特别是Ｃｕ 包Ｚｎ － Ａｌ 丝满足日本ＪＩＳ标准, 完全可用做彩电延时保险材料     

延缓铸轧辊面龟裂的措施

分析了在铸轧铝板带的操作过程中促使辊面发生龟裂的原因,阐述了延缓辊面龟裂、延长铸轧辊使用寿命的措施。     

不同配方的保鲜剂对瓶插切花延缓衰老的效果研究

对香石竹切化瓶插期不同配方的效果进行了对比实验。以蒸镏水为对照ＣＫ,自制配方中的５号９４％Ｓ＋５００ｍｇ／Ｌ ＣＡ＋２００ｍｇ／Ｌ ８－ＨＱ＋０．０２％ ＣａＣｌ２＋０．０２％ＫＣｌ）、８号（５％Ｓ＋３００ｍｇ／Ｌ ８－ＨＱ＋１００ｍｇ／Ｌ Ｂ９）对香石竹的效果最好,可延长６～８天。以４号美国保鲜剂为ＣＫ,５号、８号对香石竹的保鲜期可延长２～３天。又对香石竹花瓣衰老过程中总糖、可溶性蛋白、ＳＯＤ活     

亨廷顿学术著作述评

亨廷顿是20世纪美国乃至世界最著名的政治思想家和国际政治理论家之一,也是近半个世纪以来最具争议的政治学家。他提出的＂第三波＂、＂文明的冲突＂等观点,早已成为我们社会生活中的流行话语。其代表作《变化社会中的政治秩序》、《第三波——20世纪后期民主化浪潮》、《文明的冲突与世界秩序的重建》对世界产生了深远影响,并给予我们无尽的思索和启迪。     

建筑业工程款拖欠的成因及治理措施

着重从经济体制、政府行政行为、建筑企业及业主自身等几个方面详细阐述工程拖欠款的原因及带来的一系列危害，同时提出治理工程拖欠款的主要措施。     

黑米花青素延缓果蝇衰老作用研究

探究黑米花青素延缓衰老的能力及其作用机制。以2d龄的野生型果蝇模型生物为研究对象,饲喂添加不同质量浓度(0、1、5mg/mL)黑米花青素的培养基,采用寿命实验、饮食量检测和逆重力爬行实验方法研究黑米花青素对果蝇平均寿命和健康寿命的影响;采用蓝精灵实验检测黑米花青素对果蝇肠道完整性的影响;用荧光实时PCR测定果蝇体内抗氧化基因SOD、CAT、Rpn11 mRNA表达量的变化。研究发现,饲喂黑米花青素后果蝇平均寿命和健康寿命均高于对照组;黑米花青素对果蝇肠道有一定的保护作用;抗氧化基因mRNA表达水平显著提高(Cu/Zn-SOD,P<0.01;Mn-SOD、CAT和Rpn11, P<0.05)。研究认为,黑米花青素延缓衰老的作用可能是通过上调内源性抗氧化基因来实现的。     

从肌肉延迟疼痛的角度初步探讨“马家军”的训练

“马家军”的成功已是世界田坛当今最热门的话题之一。专家都在研究、探索“马家军”训练的真缔，以求移植于其他田径项目，本文力求从运动生理学角度对马氏训练方法作初步探讨。     

Replication of the neurochemical characteristics of Huntington's disease by quinolinic acid

Huntington's disease (HD) is an autosomal dominant neurological disorder characterized by progressive chorea, cognitive impairment and emotional disturbance. The disease usually occurs in midlife and symptoms progress inexorably to mental and physical incapacitation. It has been postulated that an excitotoxin is involved in the pathogenesis of HD. Schwarcz and colleagues have shown that quinolinic acid (QA) can produce axon-sparing lesions similar to those observed in HD. The lesions result in a depletion of neurotransmitters contained within striatal spiny neurones, for example gamma-aminobutyric acid (GABA), while dopamine is unaffected. Recently, we and others have demonstrated that in HD striatum there is a paradoxical 3-5-fold increase in both somatostatin and neuropeptide Y which is attributable to selective preservation of a subclass of striatal aspiny neurones in which these peptides are co-localized. In the present study we demonstrate that lesions due to quinolinic acid closely resemble those of HD as they result in marked depletions of both GABA and substance P, with selective sparing of somatostatin/neuropeptide Y neurones. Lesions produced by kainic acid (KA), ibotenic acid (IA) and N-methyl-D-aspartate (MeAsp) were unlike those produced by QA, as they affected all cell types without sparing somatostatin/neuropeptide Y neurones. These results suggest that QA or a similar compound could be responsible for neuronal degeneration in HD.     

泵阀滞后角影响下的钻井泵空气包排出管路流量的研究

本文在考虑泵阀滞后角的影响后,通过建立空气包动力学方程,推导出三缸单作用钻井泵空气包后排出管路流量的表达式,并论证了滞后角对排出管路流量的影响。     

京珠高速公路粤境北段工期延误原因剖析

章以京珠高速公路粤境北段为例，论述了公路工程项目工期延误的原因．