紫胶红色素异常铜含量的研究

关于紫胶原胶的含铜情况过去尚末见报道,应用原子吸收分光光度法测出紫胶原胶的铜含量为9.49ppm。将紫胶原胶分成粗粒胶、细粒胶、粉胶和紫胶虫尸体四个级分,分别测出其铜含量为8.06ppn、13.44ppm、16.38ppm、49.66ppm。 紫胶原胶中的铜高度富集于紫胶虫尸体之中,它是引起紫胶红色素铜污染的主要污染源。从紫胶的生物来源和紫胶红色素的化学本质分析,紫胶原胶中紫胶红色素的铜污染是不可避免的。     

Production of chitin—melanin complexes from <Emphasis Type="Italic">Apis mellifera</Emphasis> and study of the possibility of using them as radionuclide sorbents

Samples of a chitin-melanin complex are produced from honeybee corpses and some of their physicochemical characteristics are determined. The interaction of the complexes with radionuclides ²³³U and ⁹⁰Sr in solutions is studied. The dependence of the sorption properties of the chitin-melanin complexes with respect to radionuclides on the method of isolating and purifying them is established.     

黄斑星天牛幼虫期致病菌的研究

从黄斑星天牛幼虫虫尸上分离出球孢白僵菌、枝顶孢霉、薏孢帚霉、发束瓶孢、短柄帚霉和黄曲霉七种真菌,其中薏孢帚霉和发来瓶孢为国内新记录。利用黄斑星天牛幼虫对七种真菌进行致病性测定,七种真菌的致病力强弱顺序为;球孢白僵菌>枝顶孢霉>轮枝孢霉>薏孢帚霉>发束瓶孢>短柄帚霉>黄曲霉,其中球孢白僵菌和枝顶孢霉有较高的致病力,分别达83.33％和79.17％。     

对粘虫高毒力Bt菌株的筛选

以粘虫的初孵幼虫为供试昆虫,对东北农业大学植物保护系昆虫教研室从哈尔滨地区病死的昆虫体内分离、保存的苏云金芽孢杆茵(Bacillus thuringiensis,以下简称Bt)74个菌株进行了筛选。经初筛、复筛,从中筛选出对粘虫初孵幼虫高素力Bt菌株5株,它们的菌株号分别为31,42,72,78,87号,当菌液浓度为1.60×10 8芽孢/mL时,粘虫初孵幼虫校正死亡率分别为80％～95％,它们的致死中浓度Lc50分别为3.56×10 6芽孢/mL、4.60×10 5芽孢/mL、4.47×10 6芽孢/mL、5.49×10 6芽孢/mL、2.43×10 6芽孢/mL。     

大肠杆菌刺激蝇蛆产生抗菌肽浓度和抑菌活性的测定

[目的]确定大肠杆菌菌液刺激蝇蛆产生浓度高、活性强的抗菌肽时间和蝇蛆饲喂家禽的安全性。[方法]采用不同浓度的大肠杆菌菌液分别与麸皮混合饲喂蝇蛆,于10、24、48 h分别收集存活蝇蛆并对其粗提取抗菌肽,通过考马斯亮蓝法和抑菌试验分别测定各试验组抗菌肽粗提液的浓度和抑菌力,同时用CFU计数法测定细菌培养的家蝇幼虫的细菌含量以确定其作为绿色抗生素的安全性。[结果]浓度为3.0×107cfu/ml的大肠杆菌作用24 h的蝇蛆组产生的抗菌肽浓度最高、活性最强,且蝇蛆体内细菌含量为1.6×105cfu/g,低于国家规定的饲料细菌标准含量最低值(2×106cfu/g)。[结论]为进一步利用动物死尸、畜禽粪便生物转化蝇蛆产生大量安全、浓度高且活性强的蝇蛆抗菌肽作为绿色抗生素运用于禽类养殖业奠定了基础。     

蝉拟青霉APC20菌株对小菜蛾的室内毒力试验

[目的]为蝉拟青霉的进一步应用提供理论依据。[方法]采用生物测定法测定蝉拟青霉APC20菌株对小菜蛾的室内毒力。[结果]药后第1~4天,蝉拟青霉APC20各个浓度的孢子悬浮液对小菜蛾的校正死亡率均低于50%,而第7天,浓度为3.0×108个/ml的孢子悬浮液对小菜蛾的校正死亡率达85.11%,并且虫尸布满蝉拟青霉的菌丝体和孢子粉,说明APC20对小菜蛾呈现较强的寄生致死性。蝉拟青霉菌株APC20对小菜蛾具有较强的侵染力,处理小菜蛾第4~7天的LC50分别为5.3×105、1.1×105、1.1×104、8.9×102个/ml。[结论]蝉拟青霉APC20菌株对小菜蛾具有一定的致病力。     

Mississippi deltaic wetland survival: sedimentation versus coastal submergence

Seasonal sedimentation, measured with the aid of artificial marker horizons, was markedly different in deteriorating as compared with stable marshes in the Mississippi River deltaic plain. Deteriorating marshes receive most sediment during storm events, whereas stable marshes receive substantial amounts of sediments during the spring river flood. The deteriorating marshes are accreting at a faster rate (1.5 centimeters per year at streamside, 0.9 centimeter per year at inland areas) than the stable marshes (1.3 centimeters per year at streamside, 0.6 centimeter per year at inland areas). However, relative to local apparent sea-level rise as measured by tide gauges in each area, the deteriorating marshes are not maintaining their intertidal elevation as well as the stable marshes. These results indicate the importance of considering accretion relative to submergence.     

Experimental separation of sensory and motor functions in pea tendrils

When illuminated pea tendrils from light-grown plants are rubbed on their abaxial side, they rapidly coil in a spiral fashion. If similar tendrils are held in the dark for 3 days and then rubbed, however, they will not coil until they are subsequently illuminated. They can remain uncoiled in the dark for as long as 2 hours after stimulation, and will still coil immediately when they are illuminated. Tendrils that are rubbed and held at 25 degrees C will coil, but those treated at 5 degrees or 10 degrees C will not. However, tendrils rubbed at 25 degrees C and kept from coiling for an hour at 5 degrees C, will immediately coil when restored to the higher temperature. These observations are interpreted to imply separation of sensory and motor functions.     

对高校基本建设投资风险控制的探讨

在高校基本建设投资过程中，投资控制贯穿于投资项目的全过程。分析了高校基本建设投资风险防范及控制现状，提出了高校基本建设投资风险分阶段控制的措施，包括前期阶段投资风险防范控制措施以及加强投资控制的监督，保障基建投资的有效性。     

Seismic trapped modes in the oroville and san andreas fault zones

Three-component borehole seismic profiling of the recently active Oroville, California, normal fault and microearthquake event recording with a near-fault three-component borehole seismometer on the San Andreas fault at Parkfield, California, have shown numerous instances of pronounced dispersive wave trains following the shear wave arrivals. These wave trains are interpreted as fault zone-trapped seismic modes. Parkfield earthquakes exciting trapped modes have been located as deep as 10 kilometers, as shallow as 4 kilometers, and extend 12 kilometers along the fault on either side of the recording station. Selected Oroville and Parkfield wave forms are modeled as the fundamental and first higher trapped SH modes of a narrow low-velocity layer at the fault. Modeling results suggest that the Oroville fault zone is 18 meters wide at depth and has a shear wave velocity of 1 kilometer per second, whereas at Parkfield, the fault gouge is 100 to 150 meters wide and has a shear wave velocity of 1.1 to 1.8 kilometers per second. These low-velocity layers are probably the rupture planes on which earthquakes occur.     

Growth enhancement of plants by femtomole doses of colloidally dispersed triacontanol

Colloidal dispersions of crystalline 1-triacontanol in water, upon foliar application to corn (Zea mays L.) seedlings, resulted in growth increases at femtomole dosages (spray concentrations as low as 1 nanogram per cubic decimeter). The maximum growth increase occurred at 100 nanograms per cubic decimeter; at both higher and lower concentrations lessened growth increase was observed. The dispersions were prepared by sonication, with control of temperature and composition. Selected surfactants, which facilitate the dispersion process, are effective at 1 percent of the 1-triacontanol composition and are nontoxic.     

The widespread impact of mammalian MicroRNAs on mRNA repression and evolution

Thousands of mammalian messenger RNAs are under selective pressure to maintain 7-nucleotide sites matching microRNAs (miRNAs). We found that these conserved targets are often highly expressed at developmental stages before miRNA expression and that their levels tend to fall as the miRNA that targets them begins to accumulate. Nonconserved sites, which outnumber the conserved sites 10 to 1, also mediate repression. As a consequence, genes preferentially expressed at the same time and place as a miRNA have evolved to selectively avoid sites matching the miRNA. This phenomenon of selective avoidance extends to thousands of genes and enables spatial and temporal specificities of miRNAs to be revealed by finding tissues and developmental stages in which messages with corresponding sites are expressed at lower levels.     

Sintered superhard materials

Diamond or cubic boron nitride particles can be sintered into strong masses at high temperatures and very high pressures at which these crystalline forms are stable. Most of the desirable physical properties of the sintered masses, such as hardness and thermal conductivity, approach those of large single crystals; their resistance to wear and catastrophic splitting is superior. The sintered masses are produced on a commercial scale and are increasingly used as cutting tools on hard or abrasive materials, as wire-drawing dies, in rock drills, and in special high-pressure apparatus.     

The nature of the glass transition in a silica-rich oxide melt

The atomic-scale dynamics of the glass-to-liquid transition are, in general, poorly understood in inorganic materials. Here, two-dimensional magic angle spinning nuclear magnetic resonance spectra collected just above the glass transition of K(2)Si(4)O(9) at temperatures as high as 583 degrees C are presented. Rates of exchange for silicon among silicate species, which involves Si-O bond breaking, have been measured and are shown to be closely related in time scale to those defined by viscosity. Thus, even at viscosities as high as 10(10) pascal seconds, local bond breaking (in contrast to the cooperative motion of large clusters) is of major importance in the control of macroscopic flow and diffusion.     

既有房屋套建增层及功能改造相关问题

阐述了对既有房屋进行套建增层改造及功能改造的原因,介绍了可用于既有房屋套建增层改造及功能改造的结构形式、国内外的研究情况及作者近年来所开展的工程实践。提出了存在的问题及今后应开展的研究内容。     

Sparrows learn adult song and more from memory

Male swamp sparrows reared in the laboratory and exposed to taped songs during infancy produce accurate imitations of the material following an 8-month interval with no rehearsal. When the first rehearsal occurs, at about 300 days of age, large numbers of syllables are perfected. They are developed through invention and improvisation as well as imitation. Most are discarded at the time of song crystallization. Hence, these songbirds learn more than they manifest in full adult song.     

福建高校国防教育现状与对策

深入开展国防教育对高校实施素质教育有着重要的意义。本文在调查福建高校国防教育状况的基础上,探讨高校开展国防教育的必要性,分析当前高校国防教育存在的问题,并提出相应的对策,以促进高校国防教育的发展,使其在人才培养中发挥应有的作用。     

Reactivity of organic compounds in hot water: geochemical and technological implications

Understanding of the reactivity of organic molecules in hot water is developing from studies aimed at explaining how organic matter (kerogen) forms in natural environments and then breaks down into energy source materials. In natural systems where kerogens are depolymerized, hot water is ubiquitous and usually contains salt and minerals. Reactions such as ionic condensation, cleavage, and hydrolysis are facilitated by changes in the chemical and physical properties of water as temperature increases. These changes make the solvent properties of water at high temperature similar to those of polar organic solvents at room temperature, thus facilitating reactions with organic compounds. An understanding of aqueous organic chemistry may lead to potential applications in areas as diverse as the recycling of plastics, the synthesis of chemicals, and coal liquefaction.     

水生生物的生态毒理学研究程序

个体、种群、群落、生态系统是水生态毒理学研究的 4个层次 ,实验系统的复杂性也按此顺序增加。本研究总结了这 4个层次的毒性评价方法。无疑 ,高层次的研究结果准确性更高 ,但若在较低层次即便是在个体水平上能证实污染物的安全性 ,就没有必要再做更多工作。根据这些年的研究 ,由于污染物的亚致死影响越来越普遍 ,故有毒影响的可恢复性及恢复速度在危险性评价中就显得更为重要。另外一点是必须关注污染物间因相互作用对毒性效应及其恢复的影响。最后由于实验室条件与田间实际情况存在差异 ,故所有实验结果都必须经实际检验     

Jupiter's Magnetosphere: Plasma Description from the Ulysses Flyby

Plasma observations at Jupiter show that the outer regions of the Jovian magnetosphere are remarkably similar to those of Earth. Bow-shock precursor electrons and ions were detected in the upstream solar wind, as at Earth. Plasma changes across the bow shock and properties of the magnetosheath electrons were much like those at Earth, indicating that similar processes are operating. A boundary layer populated by a varying mixture of solar wind and magnetospheric plasmas was found inside the magnetopause, again as at Earth. In the middle magnetosphere, large electron density excursions were detected with a 10-hour periodicity as planetary rotation carried the tilted plasma sheet past Ulysses. Deep in the magnetosphere, Ulysses crossed a region, tentatively described as magnetically connected to the Jovian polar cap on one end and to the interplanetary magnetic field on the other. In the inner magnetosphere and lo torus, where corotation plays a dominant role, measurements could not be made because of extreme background rates from penetrating radiation belt particles.