Spawning behavior and larval development in Mopalia lignosa and Mopalia muscosa (Mollusca: Polyplacophora) in central California

Spawning behavior and external features of the larval development were studied in the chitons Mopalia muscosa and M. lignosa during the months of April-June, 1974, at Pacific Grove, California. ... The sequence of events in the development of the two species in the same, though some differences in timing exist.

The activity pattern of Tegula funebralis

The activity pattern of the black turban snail, Tegula funebralis (A. Adams, 1854) at Pacific Grove, California, is the subject of this article. Field studies were carried out to follow the locomotory and feeding activities of individuals of T. funebralis, to determine how much of each animal's time was spent in each of these activities, and when and under what environmental conditions they occurred.

Sulfide binding characteristics of blood serum in Calyptogena pacifica and Vesicomya gigas

The sulfide binding characteristics of blood serum were studied in vitro in two deep-sea vesicomyid clams, Calyptogena pacifica and Vesicomya gigas. Both the C. pacifica and the V. gigas serum concentrated sulfide at least an order of magnitude above ambient levels. V. gigas accumulated sulfide faster than C. pacifica, reaching saturation at 5000 M after an hour. C. pacifica bound sulfide at half the rate of V. gigas, reaching saturation in about two hours at a substantially higher concentration of sulfide. The observed distribution of the animals near cold seeps in the Monterey Submarine Canyon can be explained by their different sulfide binding abilities. The hypothesis that cold seeps are actually much more unstable sources of sulfide than previously assumed is explored.

The Silent Period of Evidence Integration in Fast Decision Making

In a typical experiment on decision making, one out of two possible stimuli is displayed and observers decide which one was presented. Recently, Stanford and colleagues (2010) introduced a new variant of this classical one-stimulus presentation paradigm to investigate the speed of decision making. They found evidence for "perceptual decision making in less than 30 ms". Here, we extended this one-stimulus compelled-response paradigm to a two-stimulus compelled-response paradigm in which a vernier was followed immediately by a second vernier with opposite offset direction. The two verniers and their offsets fuse. Only one vernier is perceived. When observers are asked to indicate the offset direction of the fused vernier, the offset of the second vernier dominates perception. Even for long vernier durations, the second vernier dominates decisions indicating that decision making can take substantial time. In accordance with previous studies, we suggest that our results are best explained with a two-stage model of decision making where a leaky evidence integration stage precedes a race-to-threshold process. © 2013 Rüter et al.

Novel nanostructured carbon nanotube electron sources

In this chapter, we present a review of our continuing efforts toward the development of discrete, low-dimensional nanostructured carbon-based electron emitters. Carbon nanotubes and nanofibers, herein referred to simply as CNTs, are one-dimensional carbon allotropes formed from cylindrically rolled and nested graphene sheets, have diameters between 1 and 500 nm and lengths of up to several millimeters, and are perfect candidates for field emission (FE) applications. By virtue of their extremely strong sp2 C-C bonding, intrinsic to the graphene hexagonal lattice, CNTs have demonstrated impressive chemical inertness, unprecedented thermal stabilities, significant resistance to electromigration, and exceptionally high axial current carrying capacities, even at elevated temperatures. These near ideal cold cathode electron emitters have incredibly high electric field enhancing aspect ratios combined with virtual point sources of the order of a few nanometers in size. The correct integration and judicious development of suitable FE platforms based on these extraordinary molecules is critical and will ultimately enable enhanced technologies. This chapter will review some of the more recent platforms, devices and structures developed by our group, as well as our contributions towards the development of industry-scalable technologies for ultra-high-resolution electron microscopy, portable x-ray sources, and flexible environmental lighting technologies. © 2012 by Pan Stanford Publishing Pte. Ltd. All rights reserved.

Advances in nanodevices and nanofabrication: Selected publications from symposium of nanodevices and nanofabrication in ICMAT2011

A variety of devices at nanometer scale / molecular scale for electronic, photonics, optoelectronics, biological and mechanical applications have been created through a rapid development of materials and fabrication technology. Further development of nanodevices strongly depends on the state-of-the-art knowledge of science and technology at the sub-100nm length scale. This symposium proceedings serves as a nice platform on which scientists and engineers can present and highlight some of the key advances in the following topics: Electronic and optoelectronic devices of nanometer scale / molecular scale. Nanomechanics and NEMS. Electromechanical coupled devices. Manipulation and aligning processes at nanometer scale / molecular scale. Quantum phenomena. Modeling of nanodevices and nanostructures. Fabrication and property characterization of nanodevices. Nanofabrication with focused beam technology, e.g., focused ion beam, laser and proton beam. © 2012 by Pan Stanford Publishing Pte. Ltd. All rights reserved.

Mechanics of indentation

The fundamental contact mechanics principles underlying nanoindentation testing techniques are reviewed. A range of material constitutive responses are covered, including elastic, plastic, and viscous deformation, and incorporating indentation of linearly viscoelastic materials and poroelastic materials. Emphasis is on routine analysis of experimental nanoindentation data, including deconvolution techniques for material properties measurements during indentation. In most cases, an analytical approach for an isotropic half-space is considered. Special cases are briefly described, including anisotropic materials, inhomogeneous composite materials and layered filmsubstrate systems. © 2011 by Pan Stanford Publishing Pte. Ltd. All rights reserved.

Handbook of nanoindentation with biological applications

Nanoindentation is ideal for the characterization of inhomogeneous biological materials. However, the use of nanoindentation techniques in biological systems is associated with some distinctively different techniques and challenges. For example, engineering materials used in the microelectronics industry (e.g. ceramics and metals) for which the technique was developed, are relatively stiff and exhibit time-independent mechanical responses. Biological materials, on the other hand, exhibit time-dependent behavior, and can span a range of stiffness regimes from moduli of Pa to GPa - eight to nine orders of magnitude. As such, there are differences in the selection of instrumentation, tip geometry, and data analysis in comparison with the "black box" nanoindentation techniques as sold by commercial manufacturers. The use of scanning probe equipment (atomic force miscroscopy) is also common for small-scale indentation of soft materials in biology. The book is broadly divided into two parts. The first part presents the "basic science" of nanoindentation including the background of contact mechanics underlying indentation technique, and the instrumentation used to gather mechanical data. Both the mechanics background and the instrumentation overview provide perspectives that are optimized for biological applications, including discussions on hydrated materials and adaptations for low-stiffness materials. The second part of the book covers the applications of nanoindentation technique in biological materials. Included in the coverage are mineralized and nonmineralized tissues, wood and plant tissues, tissue-engineering substitute materials, cells and membranes, and cutting-edge applications at molecular level including the use of functionalized tips to probe specific molecular interactions (e.g. the ligand-receptor binding). The book concludes with a concise summary and an insightful forecast of the future highlighting the current challenges. © 2011 by Pan Stanford Publishing Pte. Ltd. All rights reserved.

河南省HIV21 新近感染者耐药基因研究

目的　了解河南省艾滋病病毒Ⅰ型( HIV21) 新近感染者的耐药情况。方法　2006 年8 月- 2007 年6 月,在河南省艾滋病自愿咨询(VCT) 检测点发现的未进行抗病毒治疗的HIV21 感染者,以酶联免疫吸附试验初筛、 蛋白印迹试验确认HIV21 感染,BED2CEIA 方法检测新近感染。检出的新近感染样品进行基因型耐药检测,提取 血浆中RNA ,套式聚合酶链反应(Nested2PCR) 扩增HIV21 pol 基因区,PCR 产物双脱氧法测序,所得序列与Los Alamos HIV 标准株序列比对,构建系统进化树分析亚型;利用Stanford HIVdb Drug Resistance Database 分析耐 药相关突变(DRM) 和耐药情况。结果　共检出HIV21 新近感染39 例,扩增测序有34 例新近感染样品分析成功。 亚型分析结果为B′亚型32 例(9411 %) ,CRF01_AE 重组亚型1 例(219 %) ,C 亚型1 例(219 %) 。未发现蛋白酶抑 制剂( PI) 主要DRM ,检测到10 例(2914 %) 存在PI 次要DRM;未发现核苷类逆转录酶抑制剂(NRTI) 的DRM;3 例(818 %) 存在非核苷类逆转录酶抑制剂(NNRTI) 的DRM。耐药分析显示,有2 例(519 %) 对NNRTI 类药物耐 药。结论　目前河南省HIV21 新近感染人群中耐药状况处于中等水平,有必要加强HIV21 的耐药监测。

土壤氨基酸和氨基糖聚合物的矿化过程研究

土壤中氨基酸和氨基糖是土壤有机氮的重要组成部分，对土壤氮素供给和土壤碳、氮循环过程有重要贡献。研究氨基酸和氨基糖聚合物的矿化，对于减少氮素损失，提高氮肥利用率能够提供一定的理论依据。 当向土壤中(本试验为黑土)同时添加葡萄糖和(15NH4)2SO4时，在土壤微生物的作用下，(15NH4)2SO4会被用以合成土壤15N-氨基酸和氨基糖聚合物。新合成的这部分氨基酸和氨基糖聚合物与土壤中原有氨基酸和氨基糖聚合物的性质是否不同并且是否受到外源底物的调控。为了解决上述问题，本试验将采用Stanford and Smith的间歇好气矿化淋洗培养法，结合高效液相色谱/质谱、气相色谱/质谱联机技术(HPLC/MS，GC/MS)跟踪测定土壤中15N-氨基酸和氨基糖的同位素富集比例及其含量的变化，探讨土壤中新合成15N-氨基聚合物的矿化特征，通过研究添加葡萄糖、玉米秸秆和无机氮肥对土壤中新合成15N-氨基聚合物矿化过程的影响以及对有机氮聚合物解聚的动力－酶活性的影响，从而阐明土壤氨基聚合物矿化的碳源营养调控机制和氮源反馈调节机制及其解聚机理。研究结果表明： 1. 土壤中新合成的氨基酸和氨基糖聚合物与土壤原有氨基酸和氨基糖聚合物相比具有较高的循环速率，并且不同种氨基酸和氨基糖也分别表现出不同的矿化特征。较高循环速率的存在，将为调控其矿化过程奠定基础，因为只有快速循环的氮素才能够被调控，而且调控新合成有机氮的矿化过程，可以不断地满足作物生长对氮素养分的需求。 2. 土壤中新合成氨基聚合物的矿化受到不同外源底物调控。其中碳源(葡萄糖和玉米秸秆)能够抑制氨基聚合物矿化，但是活性碳源葡萄糖的抑制程度高于活性较低的碳源玉米秸秆，表明氨基聚合物矿化受到不同碳源活性调控。不同浓度以及不同形式氮源也能够调控土壤氨基聚合物的矿化，并且适量氮肥的加入能够抑制土壤中新合成氨基聚合物的矿化，存在氮肥的反馈抑制机制。 3. 土壤中蛋白酶、芳基酰胺酶和几丁质酶活性受到不同碳源和氮源的影响。其中碳源表现为促进作用，而氮源则表现为抑制作用。氮源对土壤酶活性的反馈抑制作用是控制土壤氮素转化的关键，而碳源只是起到维持土壤酶活性的作用。三种酶活性对外源底物的敏感性，将对于调控土壤氮素循环奠定一定的理论依据。 4. 不同处理酶活性与有机氮矿化之间表现出不同的相关性，说明酶与氮矿化之间的关系受到多方面因素影响。总体来看，蛋白酶、芳基酰胺酶和几丁质酶在水解土壤氨基酸和氨基糖聚合物的过程中起到重要作用，是有机氮聚合物重要的解聚酶。

遥控作业移动机器人环境建模方法研究

本文介绍了用于遥控机器人作业虚拟环境生成的建模方法．重点研究了基于人机交互的双目立体视觉和多视点建模方法，以克服视觉自动建模方法计算复杂、鲁棒性差的缺点．给出了环境建模的实验系统和实验结果。