WiMedia UWB 技术追踪

采用WiMedia UWB标准的越来越多 WiMedia通用无线电平台是实现传输速率高达480Mb／s（更高的传输速率正在开发中）无线个人局域网（WPAN）的基础。这个平台并不局限于某一类应用，而是允许同时存在不同的协议适配层，如图1所示。WiMedia规范既规定了一些如无线USB之间相互通信的应用，也规定其他不相互通信的接口同时存在的应用。     

Identification of extractable growth factors from small intestinal submucosa

When implanted as a biomaterial for tissue replacement, selected submucosal layers of porcine small intestine induce site-specific tissue remodeling. Small intestinal submucosa (SIS), as isolated, is primarily an acellular extracellular matrix material. In an attempt to discover the components of small intestinal submucosa which are able to induce this tissue remodeling, the material was extracted and extracts were tested for the ability to stimulate Swiss 3T3 fibroblasts to synthesize DNA and proliferate. Each of the four different extracts of small intestinal submucosa had measurable cell-stimulating activity when analyzed in both a whole cell proliferation assay (alamarBlue dye reduction) and a DNA synthesis assay ([3H]-thymidine incorporation). Proteins extracted from SIS with 2 M urea induced activity profiles in the two assays which were very similar to the activity profiles of basic fibroblast growth factor (FGF-2) in the assays. As well, the changes in cell morphology in response to the extracted proteins mimicked the changes induced by FGF-2. Neutralization experiments with specific antibodies to this growth factor confirmed the presence of FGF-2 and indicated that it was responsible for 60% of the fibroblast-stimulating activity of the urea extract of small intestinal submucosa. Western blot analysis with a monoclonal antibody specific for FGF-2 detected a reactive doublet at approximately 19 kDa and further confirmed the presence of FGF-2. Cell stimulating activity of proteins extracted from SIS with 4 M guanidine was neutralized by an antibody specific for transforming growth factor beta (TGF beta). Changes in the morphology of the fibroblasts exposed to this extract were nearly identical to changes induced by TGF beta. Although no reactive protein band was detected at 25 kDa in nonreduced western blot analysis, several bands were reactive at higher molecular weight. The identity of this TGF beta-related component of small intestinal submucosa is unknown. Identification of FGF-2 and TGF beta-related activities in SIS, two growth factors known to significantly affect critical processes of tissue development and differentiation, provides the opportunity to further elucidate the mechanisms by which this extracellular matrix biomaterial modulates wound healing and tissue remodeling.     

On the Ineffective Education of Decision Scientists

There is general agreement that the training of decision scientists during the past ten years has left much to be desired. This note presents nine rules relating to the fundamental reasons for the failure of training programs, along with suggestions for improving the present state of affairs.     

Iron repressible outer membrane proteins of Moraxella bovis and demonstration of siderophore-like activity

Moraxella bovis (strain Epp 63), grown in RPMI 1640 medium supplemented with desferrioxamine mesylate (0.05 mg/ml) resulted in cell free culture supernatants with an increased chromeazurol-S response indicating the presence of high affinity iron binding ligand(s). Supernatants of cultures where growth occurred in tryptic soy broth, RPMI 1640, or RPMI 1640-desferrioxamine supplemented with ferrous sulfate (10 micrograms/ml) were negative on the chromeazurol-S test. Growth of M. bovis in RPMI 1640 or RPMI 1640-desferrioxamine medium induced the expression of previously unrecognized outer membrane proteins whose expression was repressed when the medium was supplemented with iron and which were not produced when growth occurred in tryptic soy broth.     

Lymphomagenesis in AKR.Fv-1b congenic mice

In the AKR.Fv-1b congenic strain the Fv-1n allele of the AKR/J mice was substituted with the Fv-1b allele, thereby limiting viral replication and spread of the endogenous N-tropic murine leukemia virus. As a result of this genetic change AKR.Fv-1b mice develop a low spontaneous incidence (7%) of T-cell lymphomas and about 28% of Ly-1+ B-cell lymphomas are observed in old mice. Characteristic changes in thymus subpopulations of AKR/J mice (related to the formation of the dual tropic mink cell focus inducing (MCF) type virus in the thymus) were not observed in the thymus of AKR.Fv-1b mice. In contrast to the low susceptibility to spontaneous T-cell lymphoma development, these mice were highly sensitive to fractionated irradiation or to radiation leukemia virus (a mixture of N- and B-tropic viruses) induced T-cell lymphoma. Potential lymphoma cells (that would ultimately develop into Ly-1+ B-cell lymphomas) were demonstrated in bone marrow and spleens of 16-24-month-old mice. Analysis of the Ly-1+ IgM+ B-cell population in spleens of 18-month-old mice revealed a significant increase in this population (35% versus 2% in young spleens). The spontaneous Ly-1+ B-cell lymphoma incidence could be enhanced (up to 77%) by in vivo administration of anti-CD8 monoclonal antibody or IL-4 to 18-month-old mice. Virological analysis of T/B-cell lymphomas for class I MCF viruses indicated that Class I MCF development was tightly correlated with T-lymphoma development (except radiation induced tumors that showed no MCF provirus involvement). In contrast, Ly-1+ B-cell lymphoma development was independent of Class I MCF pathogenic virus involvement.     

Evaluating building-related symptoms using the US EPA BASE study results

In order to develop baseline data about United States office buildings, the United States Environmental Protection Agency conducted the Building Assessment Survey Evaluation (BASE) study, a systematic survey of 100 randomly selected United States office buildings, in the 1990s. This paper analyzes the self-reported work-related symptoms and job and workplace characteristics of 4326 respondents and compares results to the National Institute for Occupational Safety and Health's (NIOSH) study of 80 'complaint' buildings. Four distinct groups of symptoms, representing 'tiredness', 'mucosal irritation', 'neuropsychological', and 'lower respiratory' conditions emerged from factor analysis of work-related symptoms. The symptom grouping is identical for both surveys. Although the prevalence of each symptom is significantly higher in the NIOSH than in the BASE sample, there is overlap of the symptom distributions. In the BASE survey, 45% of the work force reported at least one work-related health symptom; 20% reported at least three symptoms. These findings imply that it is counterproductive to dichotomize buildings into healthy vs. unhealthy; instead the prevalence of health problems related to buildings span a continuum. PRACTICAL IMPLICATIONS: These results indicate that most office buildings have occupants who report building-related symptoms. This paper provides practical guidance for the comparison of building prevalences to the BASE normative data. Work-related symptom distributions and symptom groups can improve investigators' ability to identify IEQ problems.     

Thermodynamics and Kinetics of the Interaction of Carbon and Sulfur with Solid Oxide fuel Cell Anodes

Fuel cells are likely to play a key role in any low-carbon economy. Solid oxide fuel cells (SOFCs) are currently capable of sustained and continuous operation on high-purity fuels, but they must demonstrate that they can overcome a number of challenges before they are commercially viable on a large scale. Fuels such as natural gas, and those derived from renewable sources such as gasified biomass, contain many contaminants, typically sulfur- and carbon-containing compounds. To address this it will be necessary to improve our understanding of failure modes in operating SOFCs, and act on this to reduce degradation rates. A combination of techniques will be needed to develop a rigorous approach to understanding and mitigating degradation. The intent of this article is to present a synopsis of the current state of the art in our understanding of the effect of carbon and sulfur on SOFC anodes. Emphasis is placed on the comparison between thermodynamic and kinetic models, and experimental validation of these. In particular the applicability of thermodynamic models to the study of such contaminants is questioned. Additionally the uses of multiscale kinetic models capable of predicting transient conditions are reviewed alongside recent analytical techniques necessary for their validation.     

The effect of current density on H2S-poisoning of nickel-based solid oxide fuel cell anodes

Sulphur-containing impurities can have a damaging impact on nickel-based SOFC anode performance even at sub-ppm concentrations, but the electrochemical mechanism of this interaction is not fully understood. In this work, three-electrode cells of Ni-Ce_0.9Gd_0.1O_1.95/YSZ/(La_0.8Sr_0.2)MnO_3−x have been used to obtain new electrochemical data on the sulphur poisoning behaviour of Ni-based SOFC anodes operating at different current densities in the temperature range 700-750 °C. The three-electrode arrangement enabled direct measurement of anode overpotential, with concurrent impedance measurement to provide detail into the electrochemical processes occurring at the anode during sulphur poisoning.The initial, stepwise degradation on exposure to 0.5 ppm H₂S caused an increase in anode polarization resistance, which was almost entirely recoverable on removal of H₂S. Operation at higher current density was found to result in a smaller increase in anode polarization resistance. It is proposed that this initial poisoning behaviour is caused by adsorbed sulphur inhibiting surface diffusion of H atoms to active sites.Exposure to 1 ppm and 3 ppm levels of H₂S led to an observed secondary degradation which was also recoverable on removal of sulphur. This degradation was caused by an increased ohmic resistance, and was more severe at higher temperatures. The authors discuss possible explanations for this behaviour.     

Anhedonia associated with stimulant use and dependence in a population-based sample of American adults.

Prior research suggests an association between anhedonia—diminished interest or pleasure in rewarding activities—and stimulant use in selected samples. However, it is unclear whether this association generalizes to the overall population and is consistent across stimulant drug types (amphetamine vs. cocaine) and outcome characteristics (any lifetime use vs. dependence). Questions also remain as to whether the anhedonia–stimulant relationship is unique from covariance with depressed mood, psychiatric disorders, and nonstimulant substance use. The current study addressed these questions by examining anhedonia–stimulant relationships in a cross-sectional population-based sample of 43,093 American adults. Results indicated that lifetime anhedonia and depressed mood each were positively associated with lifetime stimulant use and lifetime dependence among those who reported stimulant use. Anhedonia–stimulant relationships were consistent across amphetamine- and cocaine-related outcomes and distinct from covariance with depressed mood, which exhibited no association over and above the effect of anhedonia. After adjusting for demographic, psychiatric, and nonstimulant substance use characteristics, anhedonia–stimulant associations remained significant, although effect sizes were partially attenuated. Lifetime anhedonia was also more prevalent among respondents who initiated use but did not eventually progress to dependence in comparison with individuals who never once used a stimulant drug. Anhedonia appears to be uniquely associated with lifetime use of cocaine and amphetamines and lifetime progression from use to dependence in the American population. Albeit cross-sectional in nature, these findings add further support to the generalizability and specificity of the anhedonia–stimulant relationship. Future research utilizing longitudinal and experimental designs are warranted to clarify the underpinnings of this association. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The development of the construction alternative futures explorer

The aim of the research which has led to the development of the Construction Alternative Futures Explorer (CAFE) was to devise a means of supporting and influencing the strategic thinking of managers within construction contracting organisations. CAFE is a computer based decision support tool. It supports strategic decision making by providing structure to and analysis of ‘soft' data about possible future business environments, helping construction managers to make sense of the vast amount of data about the business environment which is available to them.