Moisture-assisted crack propagation at polymer/glass interfaces

Moisture-assisted crack growth at various polymer/glass interfaces was measured as a function of applied strain energy release rate and relative humidity using a four-point flexure apparatus coupled with an inverted microscope. The specimens consisted of two glass plates bonded together with a thin layer of commercially available epoxy-acrylate, urethane-acrylate or epoxy adhesive. The crack front at the epoxy-acrylate and epoxy interfaces was relatively smooth and, above a threshold strain energy release rate, the crack growth rate was dependent on the applied strain energy release rate via a power law relationship. Crack growth along the urethane-acrylate interface was characterized by the development of finger-like perturbations along the advancing crack front. These finger-like perturbations grew until they reached a steady-state length. Once the fingers reached steady-state, the crack growth rate of the overallcrack front was dependent on the applied strain energy release rate via a power law function. With all the polymer adhesives crack growth rates increased with higher relative humidities.     

Neurotoxic lesions of basolateral, but not central, amygdala interfere with Pavlovian second-order conditioning and reinforcer devaluation effects

Considerable evidence suggests that various discrete nuclei within the amygdala complex are critically involved in the assignment of emotional significance or value to events through associative learning. Much of this evidence comes from aversive conditioning procedures. For example, lesions of either basolateral amygdala (ABL) or the central nucleus (CN) interfere with the acquisition or expression of conditioned fear. The present study examined the effects of selective neurotoxic lesions of either ABL or CN on the acquisition of positive incentive value by a conditioned stimulus (CS) with two appetitive Pavlovian conditioning procedures. In second-order conditioning experiments, rats first received light-food pairings intended to endow the light with reinforcing power. The acquired reinforcing power of the light was then measured by examining its ability to serve as a reinforcer for second-order conditioning of a tone when tone-light pairings were given in the absence of food. Acquisition of second-order conditioning was impaired in rats with ABL lesions but not in rats with CN lesions. In reinforcer devaluation procedures, conditioned responding of rats with ABL lesions was insensitive to postconditioning changes in the value of the reinforcer, whereas rats with CN lesions, like normal rats, were able to spontaneously adjust their CRs to the current value of the reinforcer. The results of both test procedures indicate that ABL, but not CN, is part of a system involved in CSs' acquisition of positive incentive value. Together with evidence that identifies a role for CN in certain changes in attentional processing of CSs in conditioning, these results suggest that separate amygdala subsystems contribute to a variety of processes inherent in associative learning.     

Folic acid to prevent neural tube defects: scientific advances and public health issues

The disturbances of blood platelet activity play an important role in the formation of haemostasis disorders in patients with end-stage renal failure (ESRF). Phospholipids and their fatty acids play an essential role in the structure and function of the platelet. In patients with ESRF, changed lipid metabolism and also changed platelet phospholipid composition are observed. Data is available on the positive influence of recombinant human erythropoietin (rHuEPO) on some lipid metabolism disorders in patients with ESRF. The aim of this study was to demonstrate the influence of rHuEPO on the fatty acid composition of platelet phospholipids in patients with ESRF treated with repeated haemodialysis. The study material included 25 patients divided into two groups: group I--14 patients treated with repeated haemodialysis, group II--11 patients also treated with haemodialysis in whom rHuEPO was administered subcutaneously in doses 2000 U twice weekly. In group I great differences in fatty acid composition were noted in comparison to the control group. In general, decreased content of unsaturated fatty acids was found in all phospholipid classes, except for phosphatidylcholine. In group II the changes in fatty acid composition were considerably less pronounced than in group I, in the case of many acids reaching the values observed in the control group. The obtained results suggest that rHuEPO improves changed platelet lipid metabolism in patients with ESRF treated with repeated haemodialysis.     

Biochemical and molecular biological analyses of space-flown nematodes in Japan, the first international caenorhabditis elegans experiment (ICE-First)

The first International Caenorhabditis elegans Experiment (ICE-First) was carried out using a Russian Soyuz spacecraft from April 19–30, 2004. This experiment was apart of the program of the DELTA (Dutch Expedition for Life science Technology and Atmospheric research) mission, and the space agencies that participate in the International Space Station (ISS) program formed international research teams. A Japanese research team that conducted by Japan aerospace Exploration Agency (JAXA) investigated the following aspects of the organism: (1) whether meiotic chromosomal dynamics and apoptosis in the germ cells were normal under microgravity conditions, (2) the effect of the space flight on muscle cell development, and (3) the effect of the space flight on protein aggregation. In this article, we summarize the results of these biochemical and molecular biological analyses.     

Assessing wave energy effects on biodiversity: the wave hub experience

Marine renewable energy installations harnessing energy from wind, wave and tidal resources are likely to become a large part of the future energy mix worldwide. The potential to gather energy from waves has recently seen increasing interest, with pilot developments in several nations. Although technology to harness wave energy lags behind that of wind and tidal generation, it has the potential to contribute significantly to energy production. As wave energy technology matures and becomes more widespread, it is likely to result in further transformation of our coastal seas. Such changes are accompanied by uncertainty regarding their impacts on biodiversity. To date, impacts have not been assessed, as wave energy converters have yet to be fully developed. Therefore, there is a pressing need to build a framework of understanding regarding the potential impacts of these technologies, underpinned by methodologies that are transferable and scalable across sites to facilitate formal meta-analysis. We first review the potential positive and negative effects of wave energy generation, and then, with specific reference to our work at the Wave Hub (a wave energy test site in southwest England, UK), we set out the methodological approaches needed to assess possible effects of wave energy on biodiversity. We highlight the need for national and international research clusters to accelerate the implementation of wave energy, within a coherent understanding of potential effects-both positive and negative.     

Toward nanometer-scale optical photolithography: utilizing the near-field of bowtie optical nanoantennas

Optically resonant metallic bowtie nanoantennas are utilized as fabrication tools for the first time, resulting in the production of polymer resist nanostructures <30 nm in diameter at record low incident multiphoton energy densities. The nanofabrication is accomplished via nonlinear photopolymerization, which is initiated by the enhanced, confined optical fields surrounding the nanoantenna. The position, size, and shape of the resist nanostructures directly correlate with rigorous finite-difference time-domain computations of the field distribution, providing a nanometer-scale measurement of the actual field confinement offered by single optical nanoantennas. In addition, the size of the photoresist regions yields strong upper bounds on photoacid diffusion and resist resolution in SU-8, demonstrating a technique that can be generalized to the study of many current and yet-to-be-developed photoresist systems.     

Scaling parallel dielectrophoresis of carbon nanotubes: an enabling geometry

Dielectrophoresis has been used as a technique for the parallel localization and alignment of both semiconducting and metallic carbon nanotubes (CNTs) at junctions between electrodes. A variation of this technique known as floating potential dielectrophoresis (FPD) allows for a self-limiting number of CNTs to be localized at each junction, on a massively parallel scale. However, the smallest FPD geometries to date are restricted to conductive substrates and have a lower limit on floating electrode size. We present a geometry which eliminates this lower limit and enables FPD to be performed on non-conducting substrates. We also discuss experiments clarifying the self-limiting mechanism of CNT localization and how it can be used advantageously as devices are scaled downwards to smaller sizes.     

A 125-mm/sup 2/ 1-Gb NAND flash memory with 10-MByte/s program speed

A single 3-V only, 1-Gb NAND flash memory has been successfully developed. The chip has been fabricated using 0.13-/spl mu/m CMOS STI technology. The effective cell size including the select transistors is 0.077 /spl mu/m/sup 2/. To decrease the chip size, a new architecture is introduced. The in-series connected memory cells are increased from 16 to 32. Furthermore, as many as 16 k memory cells are connected to the same wordline. As a result, the chip size is decreased by 15%. A very small die size of 125 mm/sup 2/ and an excellent cell area efficiency of 70% are achieved. As for the performance, a very fast programming and serial read are realized. The highest program throughput ever of 10.6-MByte/s is realized: 1) by quadrupling the page size and 2) by newly introducing a write cache. In addition, the garbage collection is accelerated to 9.4-MByte/s. In addition, the write cache accelerates the serial read operation and a very fast 20-MByte/s read throughput is realized.