Unpalatable Compounds in the Marine Gastropod Dolabella auricularia: Distribution and Effect of Diet

Sea hares are a rich source of novel secondary metabolites, most of which are derived from their algal diet, but the natural function(s) of these metabolites are largely unknown. We used field and laboratory assays to measure the palatability of extracts from the tissues, ink, and eggs of Dolabella auricularia. Digestive-gland extracts contained a wide variety of secondary metabolites, including the red algal compound prepacifinol epoxide and its derivative johnstonol, and they were unpalatable to reef fishes. Skin extracts were moderately unpalatable, but our bioassay-guided fractionation led us to (–)-7-dehydrocholesterol, rather than to an algal secondary metabolite. Ink extracts were consistently unpalatable to reef fishes only at high concentrations, suggesting either that ink must be concentrated to deter predators, that unpalatable components of ink rapidly decompose, or that ink has other functions. Unpalatability of ink was traced to a purple fraction, consistent with the hypothesis that the active compound is aplysioviolin, a known ink constituent modified from a red algal pigment. Egg extracts were moderately unpalatable; however, we could not trace this activity to any algal-derived secondary metabolite. Body-wall extract was highly palatable. Our results suggest that dietary-derived secondary metabolites play a role in chemical defense of D. auricularia via the ink, but are not responsible for unpalatability of skin or eggs. Accumulation of dietary-derived metabolites in the digestive gland may occur to detoxify a chemically rich diet, rather than or in addition to deterring predators.     

In situ characterization of structural changes and the fraction of aligned carbon nanotube networks produced by stretching

The mechanism of carbon nanotube (CNT) alignment during stretching was examined by the in situ characterization of carbon nanotube networks (CNTNs) under tensile strains using X-ray and Raman scattering techniques. A method of quantifying the inhomogeneous alignment of macroscopic CNTNs is explored based on bulk property measurements of their electrical anisotropy and X-ray diffraction diagrams. The results show that the process of stretch-induced alignment of CNTNs included straightening the waviness of the long nanotube ropes, as well as the self-assembling and denser packing of the nanotubes. For samples at a strain of 40%, the fraction of aligned nanotubes was as high as 0.85. The aligned fraction of CNTs serves as an important parameter for the quality control of the alignment process and numerical simulations of structure–property relationships of CNTNs and their composites.     

Preparation and properties of cyclic olefin copolymers multiwalled carbon nanotube nanocomposites

Nanocomposites of cyclic olefin copolymer (COC) and two types of multiwalled carbon nanotubes (MWCNTs) with different aspect ratios were prepared. The morphology, thermal behavior, and electrical conductivity of the nanocomposites were investigated by scanning electron microscopy, differential scanning calorimetry, thermal gravimetric analysis, and the DC conductivity measurement. It was found that the developed nanocomposite preparation method resulted in good nanotubes dispersion in the polymer matrix for both types of MWCNTs. No appreciable differences in glass transition temperatures were observed between the pure COC and nanocomposites. On the other hand, CNTs significantly improved the thermo‐oxidative stability of the COC. The nanocomposites showed significant delay in onset of degradation and the degradation temperature was ～ 40°C higher than that of the pure COC. The nanocomposites also showed substantially higher DC conductivity, which increased with the nanotube concentration and aspect ratio. An increase of DC electrical conductivity over 10⁹ times can be achieved by the addition of 2 wt % CNTs. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Automatic assumptions of automaticity.

Comments on J. A. Bargh and T. L. Chartrand's (see record 1999-05760-002) treatise on the pervasiveness of automaticity and its relation to self-regulation. Although Bargh and Chartrand pointed to the philosophy underlying current psychological theories about human activity, according to the present author they confused many important philosophical issues in presenting their argument. A specific point of contention is Bargh and Chartrand's misinterpretation of humanistic psychology as proposing a "causal self" as a mediator between the environment and one's responses to it. Such stimulus–organism–response formulations propose that aspects of the organism such as intention or will are shaped by and caused from without or from within by environmental or biological determinants. Thus, humanists cannot be endorsing a mediational model of activity. This misunderstanding by Bargh and Chartrand is important because such a misunderstanding of the debate between humanists and behaviorists allowed Bargh and Chartrand to erroneously subsume the humanists under the conceptual umbrella of mediational behaviorism. According to the present author, Bargh and Chartrand offered a narrow, and in some cases inaccurate, picture of the theoretical underpinnings of automaticity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

RYC91xx和BJT器件设计高性价比电源

引言 　　近年来,随着手持式电子设备的广泛普及,如移动电话、PDA、MP3播放机、数码相机等,造成了对壁式插座电源适配器需求的不断增长.对于离线电压型和小功率开关电源(MPS)设计的一项重大挑战就是成本.随着生产量的急剧上升,产品的成本约束也相应增加.而与此同时,电气技术规范变得越来越严格.因此,同时要解决这两种相互冲突的目标一直是设计工程师所面对的头等难题之一.……     

Sn-Pb合金微粒的制备和微结构

采用均匀颗粒成型法(Uniform Droplet Spray—UDS)制备出Sn—5％Pb合金微粒，颗粒的粒度分布均匀，性能一致．用非绝热容量法测量了在N2—2％H2气氛下Sn—5％Pb微粒的焓，井分析了颗粒的显微结构，结果表明：Sn—5％Pb微粒具有较大的过冷度和亚稳态结构．     

A modular architecture for rapid development of CAPP systems for agile manufacturing

Current manufacturing planning software systems, such as computer aided process planning (CAPP) systems, are general and in a closed form. It is very difficult to modify these systems to respond to a user's dynamically changing needs. These systems are no longer suitable for agile manufacturing. This paper presents research aimed at developing a novel architecture for the rapid development of CAPP systems. The architecture supports the construction of CAPP systems from prepackaged, plug-compatible software components. Specifications of the architecture and its building blocks are defined. Several important issues in architecture implementation are discussed, and an experimental system is illustrated. Finally, an Internet-based distributed CAPP system architecture is presented as a preview of next generation CAPP system development.     

Intra‐satellite networking

Aerospace remote‐sensing payloads are continuing to advance to higher speeds and increasing the demands of on‐board intra‐satellite networks. These payloads include synchronous continuous mode and asynchronous event‐driven sensor data requiring real‐time transfer with deterministic latency to capture sensor data. The networked satellite payloads include combinations of: uplinks, downlinks, sensors, processors, formatters, storage devices (recorders), and payload controller. Advanced systems planned for development in the next few years require data rates of 1–10 Gbps. An effective aerospace data‐handling network must supply real‐time data that is fault tolerant and able to withstand the rigorous conditions of launch as well as the harsh space environment. The IEEE1393‐1999 Standard for spaceborne fibre‐optic data bus (SFODB) has established the design requirements for the interconnection of these on‐board aerospace subsystems. Programs involving NASA Goddard Space Flight Center, the Air Force Research Laboratories, Space Photonics Incorporated, the University of Arkansas, and others, are in the process of developing components necessary for the implementation of the SFODB. SFODB utilizes fibre‐optic components for subsystem interconnect and eliminates cable‐to‐cable and box‐to‐box EMI, significant reductions in size, weight, and power are among the achievable characteristics that are desirable for aerospace applications. This paper discusses SFODB characteristics and the status of implementation programs. Copyright © 2006 John Wiley & Sons, Ltd.