Investigation of the Mechanical Properties of Oxide Scales on Nickel and TiAl

In this paper, a modified four-point bending test is described, which allows a quantitative determination of the mechanical properties of oxide scales on metallic substrates at temperatures from ambient to 900°C. Scale failure is detected by acoustic emission. By combining deformation data with the physical defect-structure values for the scales, fracture toughnesses have been evaluated for the cases of through-scale cracking and delamination/spalling. The test was applied to NiO scales on pure nickel and to the oxide scales on an intermetallic TiAl alloy at room temperature and 900°C, respectively. The fracture-toughness values determined in these investigations correspond to the order of magnitude expected from the rare literature data. The test itself can also be applied to a variety of brittle coatings on more-or-less ductile substrates.     

Adenosine: a mediator of the sleep-inducing effects of prolonged wakefulness

Both subjective and electroencephalographic arousal diminish as a function of the duration of prior wakefulness. Data reported here suggest that the major criteria for a neural sleep factor mediating the somnogenic effects of prolonged wakefulness are satisfied by adenosine, a neuromodulator whose extracellular concentration increases with brain metabolism and which, in vitro, inhibits basal forebrain cholinergic neurons. In vivo microdialysis measurements in freely behaving cats showed that adenosine extracellular concentrations in the basal forebrain cholinergic region increased during spontaneous wakefulness as contrasted with slow wave sleep; exhibited progressive increases during sustained, prolonged wakefulness; and declined slowly during recovery sleep. Furthermore, the sleep-wakefulness profile occurring after prolonged wakefulness was mimicked by increased extracellular adenosine induced by microdialysis perfusion of an adenosine transport inhibitor in the cholinergic basal forebrain but not by perfusion in a control noncholinergic region.     

纳米操纵机器人及其自动化设计

在纳米技术和纳米材料领域,纳米操纵机器人已经成为一种用于分析和制作原型纳米器件的使能技术.这类纳米操纵机器人拾放操作灵活,可将单个纳米器件集成到现有的微器件中来提高微器件的总体性能和灵敏度.如今这种被称作微纳米集成装配的自动化装置不再局限于实验室使用,还需要应用于工业领域.本文综述了纳米微操作机器人的产生、集成装配和自动化等方面的基础技术,同时探讨了不同种类原子力显微镜超级探针的装配方案.     

Intramedullary pressure reduction in the femur shaft in total hip endoprosthesis. Effect on the rate of thrombosis]

PROBLEM: Factors in seminal plasma stimulate an intense but transient inflammatory response in the murine endometrium at mating. The aim of our current studies is to delineate the cytokine-leukocyte interactions comprising this response and to elucidate the significance of these events in changes in the maternal immune system and as determinants of pregnancy outcome. METHOD: We have reviewed our recent findings. RESULTS: Transforming growth factor (TGF)-beta1 has been identified as the inflammation-inducing moiety in seminal plasma. Seminal TGFbeta1 initiates endometrial leukocyte infiltration by up-regulating epithelial cell expression of granulocyte-macrophage colony-stimulating factor. Other cytokines and chemokines including regulated and normal T-cell expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and monocyte chemotactic protein-1 are also implicated as mediators of macrophage and granulocyte recruitment and activation. One consequence of this inflammatory response is the induction of a transient state of hyporesponsiveness to paternal major histocompatibility class I antigens. CONCLUSION: Our studies suggest that semen may play a critical role in providing the antigenic and environmental signals necessary to initiate an appropriate maternal immune response to the conceptus during pregnancy.     

A systematic approach to assessing measurement uncertainty for CO2 emissions from coal-fired power plants - Missing contributions from the Theory of Sampling (TOS)

An augmented measurement uncertainty approach for CO₂ emissions from coal-fired power plants with a focus on the often forgotten contributions from sampling errors occurring over the entire fuel-to-emission pathway is presented. Current methods for CO₂ emission determination are evaluated in detail, from which a general matrix scheme is developed that includes all factors and stages needed for total CO₂ determination, which is applied to the monitoring plan of a representative medium-sized coal-fired power plant. In particular sampling involved significant potential errors, as identified and assessed by the Theory of Sampling (TOS), which also shows how these can be eliminated and/or minimised. Since coal-related CO₂ emission calculations not only require analytical results of the carbon content of coal itself but also of the by-products fly ash and bottom ash, sampling procedures of these three materials were also given full attention. A systematic error (bias) is present in the current sampling approach, which increases the present uncertainty estimate unnecessarily. For both primary sampling and analytical sample extraction steps, random variations, which hitherto only have been considered to a minor extent, have now also been fully quantified and included in the overall uncertainty. Elimination of all identified sampling errors lead to modified CO₂ determination procedures, which indicate that the actual CO₂ emission is approximately 20,000 t higher than the present estimate. Based on extensive empirical sampling experiments, a fully comprehensive uncertainty estimate procedure has been devised. Even though uncertainties increased (indeed one particular factor is substantially higher, the so-called “emission factor”), the revised CO₂ emission budget for the case plant complies with the official pre-determined uncertainty levels maxima in the EU guidelines.     

RiskM: A multi-perspective modeling method for IT risk assessment

Stakeholder involvement and participation are widely recognized as being key success factors for IT risk assessment. A particular challenge facing current IT risk assessment methods is to provide accessible abstractions on matters of IT risk that attend to both managerial and technical perspectives of the stakeholders involved. In this paper, we investigate whether a conceptual modeling method can address essential requirements in the IT risk assessment domain, and which structural and procedural features such a method entails. The research follows a design research process in which we describe a research artifact, and evaluate it to assess whether it meets the intended goals. In the paper, we specify requirements and assumptions underlying the method construction, discuss the structural specification of the method and its design rationale, present a prototypical application scenario, and provide an initial method evaluation. The results indicate that multi-perspective modeling methods satisfy requirements specific to the IT risk assessment domain, and that such methods, in fact, provide abstractions on matters of IT risk accessible to both a technical and a managerial audience.     

Effect on intimal hyperplasia of dexamethasone released from coated metal stents compared with non-coated stents in canine femoral arteries

Previous studies suggest that esthetic Caucasian profiles exhibit fuller lips than the norm for their race, while esthetic African American profiles are similar to those of esthetic Caucasians. The present study was undertaken to compare the profiles of female Caucasian and African American models and their nonmodel counterparts. Four groups of 30 subjects were evaluated: Caucasian models [CM], Caucasian controls [CC], African American models [AM], and African American controls [AC]. The models' profiles were photographed from current fashion magazines, the photos were scanned, and 17 landmarks were digitized. Each profile was standardized for size and oriented along the N'-Sn' line on a Macintosh 6115CD computer. Control photographs were processed in a similar manner. Twenty-six variables were measured for each profile. Means, ranges, and standard deviations were computed along with unpaired, two-tailed Student's t-tests (p<0.05) to evaluate group differences. The results showed that for the AM and AC profiles, all but two of the 26 variable were similar. For the CM and CC profiles, eight variables demonstrated significant differences. Between-race comparisons demonstrated greater numbers of parameters that were significantly different: CM/AM with 18 and CM/AC, CC/AC, and CC/AM with 22 each. Most of the differences involved the lips. Vertical soft tissue proportions for the four groups did not follow a 40/20/40 ratio. Caucasian and African American models displayed significantly different profile characteristics. The African American models and controls showed similar profile features, whereas greater differences were observed between Caucasian models and controls. Based on our study, the African American profile currently presented in the mass media is not "Caucasian-like." In fact, it appears that Caucasian models display more ethnic features than African American models do Caucasian features, suggesting that previously held concepts of facial beauty may no longer apply.     

Dopamine depletion in nucleus accumbens influences locomotion but not force and timing of operant responding

C3H mice that were inoculated with ehrlichiae isolated from a patient with human granulocytic ehrlichiosis (HGE) developed anemia and leukopenia, but by day 24, they returned to normal values. Granulocytic morulae were present in peripheral blood and spleen smears on days 5 and 10, and there was a reduction in morulae on day 17. Ehrlichiae were present in HL-60 cell cultures of blood and spleen from all mice at all intervals. Pathogenicity, but not infectivity, waned with mouse passage but could be resurrected by SCID mouse passage. Various methods were tested for their relative sensitivity in detecting infection: blood smears, HL-60 cell cultures, polymerase chain reaction (PCR) amplification of a 16S recombinant DNA target, and a mouse infectivity assay. All assays detected the HGE agent in blood during early infection, but PCR and the mouse infectivity assay were most sensitive during late infection. Xenodiagnosis demonstrated that mice remain persistently infected through 55 days.