Stontium-90 fallout from surface and underground nuclear tests

Deposition of strontium-90 per unit area per unit fission energy from surface blast of the first Chinese atomic bomb was several times heavier than that from an earlier atmospheric test series. The venting of a Russian large-scale underground test also significantly increased deposition of strontium-90 at Niigata, Japan.     

核电站用储气罐抗震分析

采用有限元法,对某核电站应急柴油发电机组配套的储气罐进行结构抗震计算分析.介绍了该结构的力学建模过程,静态载荷、地震载荷的组合和使用限制以及地震响应谱分析方法的求解过程,计算得到了结构的固有频率、振型和地震载荷下的响应,并根据RCCM规范对结构在重力、内压、地震等多种载荷组合下的应力进行评定和强度校核,结果表明该储气罐的结构强度满足规范要求.相应的计算分析方法对储气罐的抗震结构设计具有较强的借鉴意义,值得在生产实际中推广应用.     

Shock and thermal metamorphism of basalt by nuclear explosion, nevada test site

Olivine trachybasalt metamorphosed by nuclear explosion is classified into categories of progressive metamorphism: (i) Weak. Plagioclase is microfracruree, and augite contains twin lamellae. (ii) Moderate. Plagioclase is converted to glass, amd mafic minerals show intragranular deformation (undulatory extinction, twin lamellae, and, possibly, defomation lamellae), but rock texture is preserved. (iii) Moderately strong. Plagioclase glass shows small-scale flow, mafic minerals are fractured and show intragranular deformation, and rocks contain tension fractures. (iv) Strong. Plagioclase glass is vesicular, augite is minutely fractured, and olivine is coarsely fragmented, shows moscaic extinction, distinctive lamellar structures, and is locally recrystallized. (v) Intense. Rocks are converted to inhomogeneous basaltic glass.     

Potentiation by adrenaline of a proteolytic activity associated with purified myosin

Proteolytic activity accompanies myosin through three reprecipitations. The fact that this activity can be potentiated by very small doses of 1-adrenaline supports the view that adrenaline receptors are protein in nature and that adrenaline-like compounds exert their action through modification of the activity of enzymes.     

Cultural activity associated with prehistoric mammoth butchering and processing

Stacked mammoth bones at the Colby site in northern Wyoming reflect human cultural activity that is believed to have been peripheral to the butchering and processing of the animals. A projectile point found beneath the first bones placed in the pile leaves no doubt of human involvement in the stacking of the bones, but the significance of this kind of cultural activity is open to several interpretations.     

Protein kinase activity closely associated with a reconstituted calcium-activated potassium channel.

Modulation of the activity of potassium and other ion channels is an essential feature of nervous system function. The open probability of a large conductance Ca(2+)-activated K+ channel from rat brain, incorporated into planar lipid bilayers, is increased by the addition of adenosine triphosphate (ATP) to the cytoplasmic side of the channel. This modulation takes place without the addition of protein kinase, requires Mg2+, and is mimicked by an ATP analog that serves as a substrate for protein kinases but not by a nonhydrolyzable ATP analog. Addition of protein phosphatase 1 reverses the modulation by MgATP. Thus, there may be an endogenous protein kinase activity firmly associated with this K+ channel. Some ion channels may exist in a complex that contains regulatory protein kinases and phosphatases.     

Single fallout particles and zirconium-95 from the Chinese nuclear explosion of 9 May 1966

Daily fluctuations of the number of single fallout particles and activity of zirconium-95 in the groundlevel air were measured at Fayetteville (94 degrees W, 36 degrees N), Arkansas, for a period of about 3 months after the Chinese nuclear explosion of 9 May 1966. We found a cyclic pattern of variations for both zirconium-95 and fallout particles; this indicated that they were airborne for a long period and traveled far. Apparently, some of the particles circled the world more than once.     

Gulf of california: a result of ocean-floor spreading and transform faulting

Ocean-floor spreading tore southern Baja California from mainland Mexico 4 million years ago and has subsequently rafted it 260 kilometers to the northwest along the Tamayo Fracture Zone. Magnetic-anomaly profiles indicate spreading at the mouth of the gulf at 3.0 centimeters per year and a rise-crest offset of 75 kilometers inside the gulf across the Tamayo Fracture Zone.     

TMEM16A, a membrane protein associated with calcium-dependent chloride channel activity

Calcium-dependent chloride channels are required for normal electrolyte and fluid secretion, olfactory perception, and neuronal and smooth muscle excitability. The molecular identity of these membrane proteins is still unclear. Treatment of bronchial epithelial cells with interleukin-4 (IL-4) causes increased calcium-dependent chloride channel activity, presumably by regulating expression of the corresponding genes. We performed a global gene expression analysis to identify membrane proteins that are regulated by IL-4. Transfection of epithelial cells with specific small interfering RNA against each of these proteins shows that TMEM16A, a member of a family of putative plasma membrane proteins with unknown function, is associated with calcium-dependent chloride current, as measured with halide-sensitive fluorescent proteins, short-circuit current, and patch-clamp techniques. Our results indicate that TMEM16A is an intrinsic constituent of the calcium-dependent chloride channel. Identification of a previously unknown family of membrane proteins associated with chloride channel function will improve our understanding of chloride transport physiopathology and allow for the development of pharmacological tools useful for basic research and drug development.     

The product of the c-fms proto-oncogene: a glycoprotein with associated tyrosine kinase activity

The c-fms proto-oncogene is a member of a gene family that has been implicated in tumorigenesis. Glycoproteins encoded by c-fms were identified in cat spleen cells by means of an immune-complex kinase assay performed with monoclonal antibodies to v-fms-coded epitopes. The major form of the normal cellular glycoprotein has an apparent molecular weight of 170,000 and, like the product of the viral oncogene, serves as a substrate for an associated tyrosine-specific protein kinase activity in vitro. The results suggest that the transforming glycoprotein specified by v-fms is a truncated form of a c-fms-coded growth factor receptor.     

Purine overproduction in man associated with increased phosphoribosylpyrophosphate synthetase activity

In hemolyzates from red cells of two brothers with purine overproduction and gout, activity of phosphoribosylpyrophosphate synthetase is more than twofold greater than that measured in normal or other gouty individuals. The increased enzyme activity, which is also demonstrable in fibroblasts of the one patient tested, is associated with increased production of 5-phosphoribosyl-1-pyrophosphate by intact cells, an indication that the enzyme abnormality is the basis for the purine overproduction. This genetic abnormality is an example of an increased enzyme activity producing a disease state.     

Electrical phenomena associated with the activity of the membrane-bound acetylcholinesterase

Treatment of isolated electroplax with physiological solutions supplemented with either 1 molar sodium chloride, 2 molar urea, or 2 molar sucrose renders the cell insensitive to carbamylcholine, phenyltrimethylammonium, or decamethonium even at high concentrations. The treated cells have a residual resting potential of -20 +/- 10 millivolts (negative inside) and are depolarized by acetylcholine at concentrations larger than 10(-3) mole per liter. This response is not affected by d-tubocurarine but is blocked by physostigmine, diisopropylphosphorofluoridate, or strong buffers and thus depends on the catalytic activity of the membrane-bound acetylcholinesterase.     

Predicting human brain activity associated with the meanings of nouns

The question of how the human brain represents conceptual knowledge has been debated in many scientific fields. Brain imaging studies have shown that different spatial patterns of neural activation are associated with thinking about different semantic categories of pictures and words (for example, tools, buildings, and animals). We present a computational model that predicts the functional magnetic resonance imaging (fMRI) neural activation associated with words for which fMRI data are not yet available. This model is trained with a combination of data from a trillion-word text corpus and observed fMRI data associated with viewing several dozen concrete nouns. Once trained, the model predicts fMRI activation for thousands of other concrete nouns in the text corpus, with highly significant accuracies over the 60 nouns for which we currently have fMRI data.     

金钟藤蔓延成灾对土壤理化性质及土壤酶活性的影响

为了探讨金钟藤表现出的入侵性对土壤生态的影响机制,通过采样分析,比较了本地有害植物金钟藤不同覆盖程度的土壤理化性质以及土壤酶活性的变化规律.结果表明:金钟藤覆盖程度的加深,显著提高了土壤有机质、全氮、铵态氮、硝态氮、有效磷和速效钾的含量,而降低了土壤全磷的含量,但对全钾含量的影响不显著;同时也显著提高了土壤蔗糖酶、脲酶和磷酸酶的活性.有机质、全氮、铵态氮、硝态氮、有效磷和速效钾的含量在重度覆盖土中分别达44.96、2.57 g/kg和8.96、17.42、1.37、12.67 mg/kg,分别是裸土的4.40、10.28、2.30、1.57、1.83、1.90倍.在重度覆盖土中,蔗糖酶、脲酶和磷酸酶活性分别为3.39、0.52、7.70 mg/g,分别是裸土的2.92、2.26、1.39倍.可见,金钟藤改变了土壤理化性质和土壤酶活性,形成对自身生长有利的微生态环境,这可能是其能够成功入侵新区域和快速蔓延扩张的生态机制之一.     

Herpes-type virus particles associated with a fungus

A cultutre of the fungus Thraustochytrium, isolated from an estuary, was infected by ani enveloped virus. The nucleocapsid measured 110 nanometers in diameter and containied a core of DNA. The virus replicated in the nucleus. These findings stronigly suggest that the particles are a herpes-type virus.     

2株昆虫病原线虫共生菌代谢产物的抑菌作用

嗜线虫致病杆菌Xenorhabdus nematophila YL001(简称YL001)和伯氏致病杆菌Xenorhabdusbovienii YL002(简称YL002)是分别从陕西杨凌土壤中筛选的2株昆虫病原线虫体内分离鉴定获得的共生菌。对这2株昆虫病原线虫共生菌发酵液及其无菌滤液的抑菌作用进行了研究。室内活性测定结果表明,2菌株对供试的14种植物病原真菌和5种病原细菌均有不同程度的抑制作用。其中,YL001发酵液对烟草赤星菌、番茄早疫菌、辣椒疫霉菌、南瓜枯萎菌、黄瓜炭疽菌和稻瘟菌,YL002发酵液对辣椒疫霉菌、黄瓜炭疽菌、稻瘟菌和小麦纹枯菌的抑制率均在75%-100%;无菌滤液仅对辣椒疫霉菌有较强的抑制作用,EC50分别为16.65和15.19 mL/L;YL001和YL002发酵液及其无菌滤液均对水稻白叶枯菌和金黄色葡萄球菌有较强的抑制作用,对大肠杆菌和沙门氏菌的抑制作用较弱。盆栽试验结果表明,辣椒种子用YL001和YL002发酵液处理后,对辣椒疫霉病的防治效果分别为60.6%和73.2%;100 mL/L发酵液处理土壤后,对辣椒疫霉病的防治效果分别为48.72%和74.34%。     

具有质膜ATP酶活力的大豆细胞壁碎片的制备

通过反复洗涤与低速离心（１０００×ｇ,１０ｍｉｎ）,从大豆下胚轴得到的细胞壁碎片具有ＡＴＰ酶活力．酶活依赖于Ｍｇ２＋的存在,受Ｋ＋刺激和钒酸钠的强烈抑制．经加ＫＩ的悬浮液洗涤,碎片ＡＴＰ酶受叠氮化钠抑制很少,几乎不受硝酸盐抑制．表明所得的ＡＴＰ酶基本上为质膜ＡＴＰ酶．本方法简化了质膜的制备过程,在质膜及质膜ＡＴＰ酶的生理研究中有较高的应用价值．     

2株昆虫病原线虫共生菌发酵物杀虫活性研究

【目的】研究嗜线虫致病杆菌X.nematophilaYL001(YL001菌株)和伯氏致病杆菌X.bovieniiYL002(YL002菌株)发酵物的杀虫活性,为昆虫病原线虫共生菌生物农药的开发和抗虫基因工程研究提供理论依据。【方法】采用注射法、浸液法及小叶碟添加法,分别测定了YL001和YL002菌株发酵无菌滤液,对大蜡螟、粘虫、小菜蛾及棉铃虫的血腔毒性及毒杀、生长抑制和拒食活性,并对其特性进行了初步检测。【结果】YL001和YL002菌株无菌滤液对大蜡螟和粘虫5龄幼虫均具有较高的血腔毒性,用其不同培养时间的无菌滤液处理大蜡螟和粘虫,48 h后大蜡螟的死亡率均为100%,粘虫的死亡率随共生菌培养时间的延长而逐渐降低。YL001和YL002菌株的无菌滤液对小菜蛾3龄幼虫和棉铃虫初孵幼虫的毒杀活性和生长抑制活性均较低,对5龄棉铃虫幼虫的拒食活性也很低,48 h的平均拒食率分别为24.0%和29.0%。2菌株无菌滤液经50℃处理后,对大蜡螟5龄幼虫的血腔毒性无影响;经70℃处理后毒力明显降低。2菌株无菌滤液对蛋白酶较敏感。【结论】YL001和YL002菌株对害虫有较高的血腔毒性,但毒杀、生长抑制及拒食活性较低,其血腔毒素可能主要是蛋白类物质。     

喜树碱生物合成途径及其相关酶研究现状及展望

喜树碱是从喜树Camptotheca acuminata中发现的单萜类吲哚生物碱,已经成为继紫杉醇之后广泛使用的植物性抗癌药,具有非常广阔的市场前景。研究喜树碱的生物合成途径,对于了解喜树碱的合成机制,提高次生代谢工程喜树碱的产量,解决目前资源紧缺造成的供求矛盾等问题均具有重要的意义。在查阅、综合文献的基础上,将喜树碱生物合成途径以异胡豆苷为分界线,分为上游途径和下游途径;并对各种中间产物合成、关键酶和关键基因等作了详细的阐述。在此基础上,提出了调控喜树碱合成的可能方法,并提出了喜树碱合成研究未来的研究重点。图3表1参29     

蒸汽爆破对从植物中提取的多酚含量及抗氧化活性影响的研究进展

蒸汽爆破是一种新兴的原料预处理技术,通过高温高压和蒸汽瞬间释压作用于生物基质,可实现物料在组分水平、组织水平和细胞水平上的分级分离.本文简要介绍了蒸汽爆破过程中原料所发生的主要的物理、化学变化,阐述了蒸汽爆破技术对粮油、果蔬和其他原料中提取的植物多酚含量以及体外和细胞内抗氧化活性的影响,并对蒸汽爆破的研究前景进行了展望,以期进一步拓展该技术在食品加工行业的应用范围.