cssi/SciSciGPT-SciSciNet huggingface dataset:
Agonist regulation of the human platelet alpha-adrenergic receptor.

PROLONGED exposure to drugs or hormones may result in diminished physiological responsiveness which is referred to as tolerance or desensitisation. One mechanism which has been proposed to explain tolerance is a change in the state of tissue receptors following activation by drugs or hormones1. The receptor desensitisation hypothesis to explain tolerance to the β-adrenergic effects of catecholamines has been particularly well characterised in the frog erythrocyte1–4. In contrast, the regulation of catecholamine α-adrenergic receptor-mediated responses has been much less extensively investigated. Although the development of rapid desensitisation or tachyphylaxis is not a prominent feature of many α-adrenergic responses, rat parotid cells lose their α-adrenergic mediated potassium secretory response after 2–4 min of (−)adrenaline exposure5. Concomitantly, there was a decrease in binding of the α-adrenergic antagonist 3H-dihydroergocryptine to these cells which was thought to represent either a decrease in number or affinity of α-adrenergic receptors. It has been hypothesised that α- as well as β-adrenergic responses in man diminish with chronic exposure to high concentrations of catecholamines6. The human platelet would seem to be a useful tissue to investigate this possibility, as catecholamine-induced platelet aggregation is mediated through α-adrenergic receptors. We have recently characterised the human platelet α-adrenergic receptor by ligand binding assay using 3H-dihydroergocryptine and have shown good correlation between binding characteristics and the biochemical and physiological manifestations of α-adrenergic receptor activation7. We now report that the human platelet α-adrenergic receptor is subject to ligand regulation as assessed by 3H-dihydroergocryptine binding and that this regulation is reflected in altered physiological function.
TGFβ enforces activation of eukaryotic elongation factor-2 (eEF2) via inactivation of eEF2 kinase by p90 ribosomal S6 kinase (p90Rsk) to induce mesangial cell hypertrophy

eEF2 phosphorylation is under tight control to maintain mRNA translation elongation. We report that TGFβ activates eEF2 by decreasing eEF2 phosphorylation and simultaneously increasing eEF2 kinase phosphorylation. Remarkably, inhibition of Erk1/2 blocked the TGFβ-induced dephosphorylation and phosphorylation of eEF2 and eEF2 kinase. TGFβ increased phosphorylation of p90Rsk in an Erk1/2-dependent manner. Inactive p90Rsk reversed TGFβ-inhibited phosphorylation of eEF2 and suppressed eEF2 kinase activity. Finally, inactive p90Rsk significantly attenuated TGFβ-induced protein synthesis and hypertrophy of mesangial cells. These results present the first evidence that TGFβ utilizes the two layered kinase module Erk/p90Rsk to activate eEF2 for increased protein synthesis during cellular hypertrophy.
Toxic Metals Stimulate Inflammatory Cytokines in Hepatocytes through Oxidative Stress Mechanisms

Hepatocytes, as well as nonparenchymal cells, secrete proinflammatory cytokines and chemokines that are involved in the pathology of many liver diseases. In particular, tumor necrosis factor-alpha (TNFalpha), as well as members of the CXC family of chemokines, including interleukin (IL)-8 in humans and macrophage inflammatory protein (MIP)-2 in rodents, have been implicated in both damage and repair processes associated with various hepatotoxins. In the liver, cytokine secretion is usually associated with nonparenchymal cells, particularly Kupffer cells. In the present studies, cytokine gene expression and secretion were investigated in hepatocytes treated with cadmium chloride (CdCl2) or vanadium pentoxide (V2O5). Using human Hep G2 cells and freshly isolated rodent hepatocytes, it was demonstrated that metals increase gene expression and secretion of CXC chemokines and TNFalpha. IL-8 and MIP-2 secretion induced either by the metals or H2O2 were inhibited by antioxidants such as tetramethyl-thiourea and N-acetyl-cysteine. In vitro neutralization experiments with TNFalpha and in vivo studies with TNFalpha receptor knockout mice indicated that the metals directly stimulate CXC chemokine secretion without the need for TNFalpha. Taken together these studies indicate that, in addition to other inflammatory mediators and acute phase proteins, cytokines and chemokines are produced by hepatocytes, which may participate in hepatotoxic responses. The events responsible for their expression involve cellular redox changes.
Whole body arginine metabolism and nitric oxide synthesis in newborns with persistent pulmonary hypertension

Whole Body Arginine Metabolism and Nitric Oxide Synthesis in Newborns with Persistent Pulmonary Hypertension
Near-interface characterization of diamond films on silica and silicon

The near-interface structure of diamond films grown from a methane and hydrogen gas mixture by microwave plasma enhanced chemical vapor deposition has been studied. Freestanding diamond films grown on both silica and silicon at two different methane concentrations were analyzed by scanning and transmission electron microscopies, electron diffraction, Raman spectroscopy, and secondary ion mass spectroscopy. It was found that the substrate chemistry greatly influenced the nature of the carbon initially deposited on the substrate surface. Diamond formed large flat contact areas on silicon, whereas on silica a particulate type of intermediate layer formed first because of the chemical reactions occurring on and/or with the surface. It was found that the phase content of the films was greatly affected by the methane concentration in hydrogen. At the low (1.0% or less) methane concentrations in hydrogen, phase pure diamond formed; while at the high (5.0%) methane concentration in hydrogen, graphite and disordered carbon were codeposited along with diamond during the early growth stages. Silicon carbide was detected at the diamond interfaces which appeared in discrete areas on silica as opposed to a rather continuous layer as is believed to form on silicon.
Streets, Bedrooms, and Patios: The Ordinariness of Diversity in Urban Oaxaca

Streets, Bedrooms, and Patios: The Ordinariness of Diversity in Urban Oaxaca. Michael James Higgins and Tanya L. Coen. Austin: University of Texas Press, 2000. ix. 312 pp., notes, bibliography, index.
Lactational Output of DDT Fed Prepartum to Dairy Cattle

Abstract Dry dairy cows and heifers approaching their first lactation were fed 1,1,1-trichloro-2,2-bis(4′-chlorophenyl) ethane (DDT) from the 90th to the 30th day before expected parturition. A control and three treatment groups of four animals each were used. Feed contamination levels of 30, 300, and 600 ppm were approximated; mean total intakes of crystalline DDT were 28, 250, and 520 g per cow for the treated groups. No gross signs of toxicity were observed. Body fat DDT concentrations rose to 16, 253, and 590 ppm in the treated groups. Concentrations fell after cessation of intake at rates of 8 to 10% per week. Maximum milk fat DDT concentrations after calving were 19, 231, and 812 ppm for the treated groups, respectively, and declined through the lactation at from 9 to 11% per week. The DDT level in the milk fat of the cows with lowest intake did not reach 1 ppm until after 17 to 26 wk of lactation. Therefore, giving dry cows or heifers feed contaminated at or above this level is impractical, even if the feed is withdrawn a month before calving. Whole blood levels of DDT, determined twice during the experiment, were closely associated with body stores of DDT, particularly in the animals fed at the two higher levels of the insecticide.
Endocannabinoid-Mediated Long-Term Plasticity Requires cAMP/PKA Signaling and RIM1α

Summary Endocannabinoids (eCBs) have emerged as key activity-dependent signals that, by activating presynaptic cannabinoid receptors (i.e., CB1) coupled to G i/o protein, can mediate short-term and long-term synaptic depression (LTD). While the presynaptic mechanisms underlying eCB-dependent short-term depression have been identified, the molecular events linking CB1 receptors to LTD are unknown. Here we show in the hippocampus that long-term, but not short-term, eCB-dependent depression of inhibitory transmission requires presynaptic cAMP/PKA signaling. We further identify the active zone protein RIM1α as a key mediator of both CB1 receptor effects on the release machinery and eCB-dependent LTD in the hippocampus. Moreover, we show that eCB-dependent LTD in the amygdala and hippocampus shares major mechanistic features. These findings reveal the signaling pathway by which CB1 receptors mediate long-term effects of eCBs in two crucial brain structures. Furthermore, our results highlight a conserved mechanism of presynaptic plasticity in the brain.
SU-E-T-413: Dose Verification for Linac-Based SRS Commissioning and Patient Specific QA.

Purpose:Stereotactic Radiosurgery(SRS) program commissioning is currently relied on Radiological Physics Center (RPC) Head Neck phantom with Thermo Luminescent Dosimeters(TLDs) for dose verification. However, due to the limited accessibility of RPC Head Neck phantom, ongoing QA or patient specific dose verification is not performed in most clinics. In this study, we proposed an SRSdose verification approach for both SRS commissioning and patient specific dose verification with widely available clinical instruments. Methods:SRS treatment plans were imposed onto a 14cm thick conventional solid water phantom (30cm × 30cm), with a PTW micro‐chamber in the middle. Treatment couch angles were renormalized to 90 or 270 degrees for two reasons: 1) micro‐chamber's axis was parallel to gantry rotation axis during all the arc beam delivery, which minimizes the angle dependence effect (axis tilt) of micro‐chamber. 2) Any collision between the cone and conventional solid water phantom would be avoided and there would be minimum attenuation effect from the couch. The arc verification plan was then recalculated and compared to the measured absolute dose by PTW micro‐chamber. An End‐to‐End test with a CyberKnife Head Neck phantom and GAFChromic EBT2 film was utilized as secondary dose delivery verification. Results: Cones with all twelve different sizes in SRS commissioning were tested. For the cone size from 10mm to 30mm, the micro‐chamber measurements agreed with the computer calculations within 3%. However, when the cone size was reduced to 5mm, micro‐chamber measurement was 10% lower than planned dose, indicating underdose effect for small cone size. Additional measurements with Cyberknife head phantom confirmed the dose delivery accuracy was within 5%. Conclusions: A simple SRSdose verification method which only requires micro‐chamber and conventional solid water phantom has been presented and verified. This approach will be valuable for SRS commissioning and ongoing SRS QA.
Anionic carbonyl complexes of the group VI transition metals with sulfur containing ligands

Abstract Anionic complexes of the type [M(CO)4(dpet)]− (where M is Cr, Mo or W and dpet is the anion of 2-(diphenylphosphino)ethanthiol) are readily prepared by the reaction of the Tl(dpet) and [M(CO)5X]− anions (X = halogen). These complex anions appear to have the normal octahedral geometry with the dpet ligand coordinated through both the P and S atoms. When treated with methyl or allyl halides, neutral complexes of the type M(CO)4(dpet—R) are formed (where R is an allyl or methyl group now bound to the sulfur atom). By treating TlI salts of o-aminothiophenol (atp), o-methylmercaptophenol (nmp) and methylxanthic acid (mxt), with [M(CO)5]− anions, the respective complexes [M(CO)4(atp)]−, [M(CO)4(mmp)]− and [M(CO)5(mxt)]− are formed.
Papilledema in Patients with Severe Pulmonary Emphysema

Papilledema in association with severe pulmonary insufficiency has been uncommon until recently when it has been reported with increased frequency. Common features of reported cases, including three from the Mayo Clinic, have included emphysematous pulmonary changes alone or associated with chronic asthma, bronchitis, or fibrosis. Impaired intrapulmonary mixing of gases has been of such severe degree as to lead to both hypoxia and retention of carbon dioxide. Frequently polycythemia, cor pulmonale and congestive failure also have been present. Neurologic manifestations have included altered sensorium, confusion, headache, weakness, blurred vision, muscular twitching and, occasionally, coma complicating respiratory infection, pharmacologic depression of respiration or therapy with high tensions of oxygen. Papilledema is apparently one of the most extreme and unusual signs of the adverse effects of severe pulmonary insufficiency on the central nervous system.
Chlorine monofluoride assisted intercalation in graphite

Abstract Phosphorus pentafluoride will form a phosphorus fluoride intercalation compound with graphite in the presence of chlorine fluoride. It will not, under experimental conditions, intercalate when reacted with graphite alone or in the presence of hydrogen fluoride. Apparently, sufficient oxidizing power is needed before intercalation will occur.
Prepregnancy body mass index and the occurrence of severe hypertensive disorders of pregnancy.

Background:Prepregnancy overweight is a risk factor for mild preeclampsia and mild transient hypertension of pregnancy. Its association with severe subtypes of these disorders has received less attention.Methods:To assess the association of prepregnancy body mass index (BMI) with severe and mild pre
A Quality Control Mechanism Coordinates Meiotic Prophase Events to Promote Crossover Assurance

Meiotic chromosome segregation relies on homologous chromosomes being linked by at least one crossover, the obligate crossover. Homolog pairing, synapsis and meiosis specific DNA repair mechanisms are required for crossovers but how they are coordinated to promote the obligate crossover is not well understood. PCH-2 is a highly conserved meiotic AAA+-ATPase that has been assigned a variety of functions; whether these functions reflect its conserved role has been difficult to determine. We show that PCH-2 restrains pairing, synapsis and recombination in C. elegans. Loss of pch-2 results in the acceleration of synapsis and homolog-dependent meiotic DNA repair, producing a subtle increase in meiotic defects, and suppresses pairing, synapsis and recombination defects in some mutant backgrounds. Some defects in pch-2 mutants can be suppressed by incubation at lower temperature and these defects increase in frequency in wildtype worms grown at higher temperature, suggesting that PCH-2 introduces a kinetic barrier to the formation of intermediates that support pairing, synapsis or crossover recombination. We hypothesize that this kinetic barrier contributes to quality control during meiotic prophase. Consistent with this possibility, defects in pch-2 mutants become more severe when another quality control mechanism, germline apoptosis, is abrogated or meiotic DNA repair is mildly disrupted. PCH-2 is expressed in germline nuclei immediately preceding the onset of stable homolog pairing and synapsis. Once chromosomes are synapsed, PCH-2 localizes to the SC and is removed in late pachytene, prior to SC disassembly, correlating with when homolog-dependent DNA repair mechanisms predominate in the germline. Indeed, loss of pch-2 results in premature loss of homolog access. Altogether, our data indicate that PCH-2 coordinates pairing, synapsis and recombination to promote crossover assurance. Specifically, we propose that the conserved function of PCH-2 is to destabilize pairing and/or recombination intermediates to slow their progression and ensure their fidelity during meiotic prophase.
New approach to linearity testing of A/D converters

A new method is developed for integral-non-linearity (INL) testing of analogue-to-digital converters (ADC). While providing better accuracy and repeatability, the new method uses only a fraction of the test time used by either the servo-loop method or the histogram method, which are the traditional test methods currently used in the industry. The proposed new method in INL testing is an application of digital signal processing (DSP), namely the fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) methods, for filtering out the INL information from the digital data generated by an ADC under test. The approach takes advantage of the fact that the INL is directly related to the harmonic distortions of an ADC, and creates a method to extract the INL information from the frequency components that are INL related. By doing this, the environmental noises, such as test system noise and some device noise, are not taken into account when the INL is calculated. This is different from the servo-loop...
Structured development of menu-driven application systems

Presenting the user of an application system with a menu of choices is a valuable approach to the human interface problem. In a complex system this may take the form of a tree of menus that is presented. This tree of menus can also be used as the basis for a top-down development of the application system. This paper describes a programming system which can be used to acquire the tree of menus and structure the development of a menu-driven application system in a top-down fashion. Objects called augmented menus contain not only the textual representation of the choices presented the user (in three forms), but also the action to be taken for each choice. A menu-manager program accesses the specified augmented menu, displays the choices and executes the selected action. This function eleminates much of the work of the application developer. This development system is illustrated with three applications: an information storage and retrieval system, a class-roll record-keeping system and a text-editing system.
Evaluation of SO2 emission scenarios with a nonlinear atmospheric model

Abstract A method has been developed for the rapid calculation of SO2 and SO42− concentrations and deposition using a nonlinear atmospheric model. This method is designed for application in assessment problems where the impacts of many SO2 emission scenarios must be determined. The approach consists of first running an atmospheric simulation model in a conventional fashion. Calculated concentrations of oxidants and other substances affecting the chemistry of SO2 are stored for use in a subsequent calculation. A second calculation, which treats only S compounds and compounds strongly coupled to S (i.e. H2O2), is repeated for each SO2 emission scenario under consideration. This method is illustrated using a one-dimensional Lagrangian model; the application to other models is straightforward. Numerical tests indicate that prediction of S concentrations and deposition can be made with high accuracy. Errors are a few per cent or less for a wide range of conditions.
A portable lisp compiler

The programming language LISP is usually implemented via an interpreter, and a compiler is added later as a LISP program. However, all such production compilers known to the authors produce explicit instructions for the given computer being used. This paper describes the development of a portable LISP compiler in the sense that only Standard LISP functions are used in its definition and the output is a sequence of abstract machine codes, easily mapped to instruction sequences on current computers. The resulting code is quite efficient, demonstrating once again the maxim that most compiler optimization is largely machine independent.
The Use of Transscrotal Venography to Guide Treatment of a Persistent Grade 3 Varicocele After Failure of Previous Microsurgical Varicocelectomy and Embolization

Varicoceles affect approximately 15% of male patients, most of whom have resolution of symptoms and objective findings with microscopic subinguinal varicocelectomy. We present an interesting case of a 16-year-old male patient with persistent symptomatic varicocele despite varicocelectomy and gonadal vein embolization.
Voting power in a system of compound majority rule

Abstract In 1973, the United States Supreme Court ruled that a water district's voting scheme that apportioned votes on the basis of the assessed valuation of acreage in the district was constitutional. Among the justifications for the constitutionality of this scheme was the concurrent requirement that legislation be approved by a majority of voters as well as by a majority of weighted votes. However, analysis of this voting scheme in game-theoretic terms indicates that this justification is only partial: when two sets of winning coalitions must form simultaneously in order to pass legislation, the voting power of each voter in the combined system equals the mean of the voting power afforded each voter in each simple system. The results can be generalized to three or more concurrent requirements.
Low temperature heat capacities of superconducting molybdenum carbides.

Low temperature heat capacities for molybdenum carbides studied for similarities of thermodynamic and superconducting properties
Scaffolding argumentation about water quality: a mixed-method study in a rural middle school

A common way for students to develop scientific argumentation abilities is through argumentation about socioscientific issues, defined as scientific problems with social, ethical, and moral aspects. Computer-based scaffolding can support students in this process. In this mixed method study, we examined the use and impact of computer based scaffolding to support middle school students’ creation of evidence-based arguments during a 3-week problem-based learning unit focused on the water quality of a local river. We found a significant and substantial impact on the argument evaluation ability of lower-achieving students, and preliminary evidence of an impact on argument evaluation ability among low-SES students. We also found that students used the various available support—computer-based scaffolding, teacher scaffolding, and groupmate support—in different ways to counter differing challenges. We then formulated changes to the scaffolds on the basis of research results.
Noninvasive evaluation of normal and abnormal prosthetic valve function

Noninvasive techniques are helpful in evaluating the function of mechanical prostheses and tissue valves. Combined phonocardiography and M-mode echocardiography together with cinefluoroscopy are the most useful noninvasive techniques in differentiating normal from abnormal metallic prosthetic valve function. The intensity of the opening and closing clicks and associated murmurs will depend on the type of prosthetic valve, the heart rate and rhythm and the underlying hemodynamic status. Arrhythmias or conduction disturbances, or both, may produce motion patterns that mimic some of the echocardiographic signs of malfunctioning prosthetic valves. Differentiation of thrombus formation or tissue ingrowth from paravalvular regurgitation or dehiscence is possible by noninvasive techniques. Disc variance, a potentially serious and lethal problem with the older Beall valves, can be readily detected by cinefluoroscopy and echophonocardiography. With regard to bioprosthetic valves, two-dimensional echocardiography is superior to M-mode echocardiography in detecting primary valve failure. In addition, detection of vegetations, valve alignment and ring and individual leaflet motion can be best accomplished by two-dimensional echocardiography. Of greater importance is the patient serving as his or her own control in the follow-up assessment of prosthetic valve function by noninvasive techniques.
Expert identification in community question answering: exploring question selection bias

Community Question Answering (CQA) services enables users to ask and answer questions. In these communities, there are typically a small number of experts amongst the large population of users. We study which questions a user select for answering and show that experts prefer answering questions where they have a higher chance of making a valuable contribution. We term this preferential selection as question selection bias and propose a mathematical model to estimate it. Our results show that using Gaussian classification models we can effectively distinguish experts from ordinary users over their selection biases. In order to estimate these biases, only a small amount of data per user is required, which makes an early identification of expertise a possibility. Further, our study of bias evolution reveals that they do not show significant changes over time indicating that they emanates from the intrinsic characteristics of users.
The mathematical physics of rainbows and glories

Abstract A detailed qualitative summary of the optical rainbow is provided at several complementary levels of description, including geometrical optics (ray theory), the Airy approximation, Mie scattering theory, the complex angular momentum (CAM) method, and catastrophe theory. The phenomenon known commonly as the glory is also discussed from both physical and mathematical points of view: backward glories, rainbow-glories and forward glories. While both rainbows and glories result from scattering of the incident radiation, the primary rainbow arises from scattering at about 138° from the forward direction, whereas the (backward) glory is associated with scattering very close to the backward direction. In fact, it is a more complex phenomenon physically than the rainbow, involving a variety of different effects (including surface waves) associated with the scattering droplet. Both sets of optical phenomena—rainbows and glories—have their counterparts in atomic, molecular and nuclear scattering, and these are addressed also. The conceptual foundations for understanding rainbows, glories and their associated features range from classical geometrical optics, through quantum mechanics (in particular scattering from a square well potential; the associated Regge poles and scattering amplitude functions) to diffraction catastrophes. Both the scalar and the electromagnetic scattering problems are reviewed, the latter providing details about the polarization of the rainbow that the scalar problem cannot address. The basis for the complex angular momentum (CAM) theory (used in both types of scattering problem) is a modification of the Watson transform, developed by Watson in the early part of this century in the study of radio wave diffraction around the earth. This modified Watson transform enables a valuable and accurate approximation to be made to the Mie partial-wave series, which while exact, converges very slowly at high frequencies. The theory and many applications of the CAM method were developed in a fundamental series of papers by Nussenzveig and co-workers (including an important interpretation based on the concept of tunneling), but many other contributions have been made to the understanding of these beautiful phenomena, including descriptions in terms of so-called diffraction catastrophes. The rainbow is a fine example of an observable event which may be described at many levels of mathematical sophistication using distinct mathematical approaches, and in so doing the connections between several seemingly unrelated areas within physics become evident.
Light Stimulation of the Sodium Pump in Epithelia

WHEN pieces of isolated skin are exposed to intense flashes of light lasting less than 1 ms, an electrical response can be detected between electrodes placed on the two sides1. This consists of a 1 ms initial response during which the anatomical inside surface of the skin is negative, followed by a slower series of waves of varying polarity but dominated by a component with a peak latency of usually 10–20 ms, positive inside (Fig. 1, +70 mV). In the previous report1, this complex was termed the early response to distinguish it from a later response, a much slower transient alteration in potential lasting several seconds that was observed in frog skin. Both the early and late responses increase linearly with stimulus energy.
Hyperlipemic-very low density lipoprotein, intermediate density lipoprotein and low density lipoprotein act synergistically with serotonin on vascular smooth muscle cell proliferation.

Background: Previous studies have shown that very low density lipoprotein (VLDL), intermediate density lipoprotein (IDL) and low density lipoprotein (LDL) from hyperlipidemic plasma are more atherogenic than those from normal plasma. Since platelet aggregation at sites of atherosclerotic injury exposes the cells to high concentrations of serotonin (5HT), a known mitogen for vascular smooth muscle cells (VSMCs), it was examined whether VLDL, IDL or LDL from plasma of 1% cholesterol-fed rabbits can potentiate the mitogenic effect of SHT on VSMC. Methods: Growth arrested primary aortic VSMC in 1st or 2nd passage were incubated with different concentrations of VLDL, IDL or LDL in the presence or absence of pertusis toxin (PTX) for 24 h followed by incubation with 5HT for 24 h. The amount of [ 3 H]thymidine incorporated into the DNA as well as the increase in cell number was measured. Results: Either VLDL, IDL or LDL at a concentration of 60 μg/ml induced proliferation of VSMC by themselves (196, 137 or 122% increase in [ 3 H]thymidine incorporation, or 122, 119 or 122% increase in cell number, respectively when compared to the control, P > 0.05). This effect on DNA synthesis was markedly potentiated by 50 μM SHT to 465, 714 and 1369%, respectively. PTX reversed the mitogenic effect of 5HT, but not that of VLDL, IDL or LDL. Conclusion: These results suggest that even low concentration of VLDL. IDL or LDL from hypercholesterolemic plasma may significantly potentiate the mitogenic effect of 5HT, that is released by aggregating platelets at sites of vascular damage.
The Serious Side of Ebonics Humor

L'A. analyse les strustures de l'effet comique dans les dessins humoristiques en anglais vernaculaire de la communaute noir americaine. L'humour utilise la transition entre les deux systemes linguistiques anglais et africain, entre les deux cultures, leurs mecanismes identificatoires et leurs stereotypes
Theoretical study of deep-defect states in bulk PbTe and in thin films

The nature of neutral defect states in PbTe, a narrow band-gap semiconductor, has been studied using density functional theory and supercell models. We find that the defect states associated with different substitutional impurities and native point defects found in bulk PbTe are preserved in the film geometry, but get modified as one goes from the surface to the subsurface layers and then to the bulklike layers. These modifications, which usually occur in the neighborhood of the band gap, will impact the transport properties of the films. Energetic studies of different impurities and native defects embedded in bulk PbTe and in different layers of PbTe films show different energy landscapes, depending on the nature of the defects. This has important implications in doping mechanism and the distribution of the defects in bulk PbTe with grain boundaries and in PbTe nanostructures. Available experimental data are discussed in the light of our theoretical results. Our results in pure PbTe(001) films are consistent with earlier works and with experiment.
Tubal sterilization and hot flashes

Abstract A cross-sectional study was conducted among women ages 40–60 years to assess the association between tubal sterilization and the occurrence of any, moderate/severe, or daily hot flashes. Although women with tubal sterilization were more likely to report hot flashes than were nonsterilized women, this association was largely due to differences in characteristics between the women, particularly body mass.
Association of "lanthanum-staining material" with hemagglutination by rubella virus.

SummaryErythrocytes from 24-hr-old chicks have, on the external surface of the plasma membrane, a structure which appears to possess all of the characteristics of previously described lanthanum-staining material. Removal of this layer by treatment with very low concentrations of phospholipase C results in failure of the cells to be agglutinated by the virus.
The role of superoxide ions in the degradation of synthetic absorbable sutures

The objective of this study was to examine the effect of superoxide ion-induced degradation on synthetic absorbable biomaterials. Synthetic absorbable sutures were used as the model compounds. Inflammatory cells, particularly leukocytes and macrophages, are able to produce highly reactive oxygen species, such as superoxide (. O(2)(-)), during inflammatory reactions to foreign materials. Superoxide ions may act as oxygen nucleophile agents to attack biomaterials. In this study, the changes in tensile breaking force, thermal properties, and the surface morphology of five commercial (2/0 in size) synthetic absorbable sutures (Dexon, Vicryl, PDS II, Maxon, and Monocryl) as a function of superoxide ion concentration at 25 degrees C for 24 h were studied. Among the five absorbable sutures and over the concentration range of this study, the monofilament Monocryl suture was the most sensitive toward superoxide ion-induced degradation, followed by Maxon, Vicryl, Dexon, and PDS II sutures. The amount of tensile breaking force loss over a 24 h period ranged from as low as 3% to as high as 80%, depending on the type of absorbable sutures, the reaction time, and the superoxide ion concentration. All five absorbable sutures showed significant reductions in both the T(m) and T(g). Unlike the surface morphological changes of absorbable sutures in conventional buffer solutions, the effect of superoxide ion-induced degradation on the surface morphologies of these five absorbable sutures was unique, particularly the moon-crater-shaped impressions of various sizes and depths found in Monocryl and Maxon sutures, which defied the anisotropic characteristics of fibers.
An Acute Abdominal Catastrophe in a HIV Positive Patient

We report this case of a 45-year-old man with HIV-AIDS on HAART therapy who presented with acute abdominal pain and renal failure. He was found to have pneumatosis intestinalis on computerized axial tomography scan of the abdomen. He underwent emergent explorative laparotomy, which revealed a necrotic large bowel segment for which a right-sided hemicolectomy and ileostomy were performed. The patient subsequently developed septic shock and hypoxic respiratory failure. He expired a week after the surgical procedure. Acute abdominal events due to vascular catastrophes secondary to hypercoagulability, endothelial dysfunction and accelerated atherosclerosis have been reported in HIV positive patients.
Health behaviors associated with use of body building, weight loss, and performance enhancing supplements.

Purpose To identify health-related behaviors associated with potentially harmful dietary supplements (DS) - body building (BB), weight loss (WL) and performance enhancing (PE), explore common reasons and sources of information for DS use. Methods Based on the 2005 Survey of 16,146 U.S. military personnel, BB users were dichotomized as yes (regular use - taking any supplement of BB at least once a week in past 12 months) or no; similarly defined for WL and PE. Weighted logistic regression models are used. Results BB, WL and PE were used by 19.4%, 17.0%, and 8.0% of participants, respectively. Significantly more users were overweight or obese: BMI ≥25 (vs. BMI Conclusions The dietary supplements: BB, WL and PE were used by significant proportions of service members, and associated with risk-taking behaviors that may affect overall military readiness and public health.
A lysine deacetylase Hos3 is targeted to the bud neck and involved in the spindle position checkpoint

An increasing number of cellular activities can be regulated by reversible lysine acetylation. Targeting the enzymes responsible for such posttranslational modifications is instrumental in defining their substrates and functions in vivo. Here we show that a Saccharomyces cerevisiae lysine deacetylase, Hos3, is asymmetrically targeted to the daughter side of the bud neck and to the daughter spindle pole body (SPB). The morphogenesis checkpoint member Hsl7 recruits Hos3 to the neck region. Cells with a defect in spindle orientation trigger Hos3 to load onto both SPBs. When associated symmetrically with both SPBs, Hos3 functions as a spindle position checkpoint (SPOC) component to inhibit mitotic exit. Neck localization of Hos3 is essential for its symmetric association with SPBs in cells with misaligned spindles. Our data suggest that Hos3 facilitates cross-talk between the morphogenesis checkpoint and the SPOC as a component of the intricate monitoring of spindle orientation after mitotic entry and before commitment to mitotic exit.
Photoelectric current distribution and bit error rate in optical communication systems using a superfluorescent fiber source

In spectrum-sliced wavelength division multiple access (WDMA) optical communication systems, excess noise due to the thermal nature of the broadband source, such as the superfluorescent fiber source (SFS), limits the signal-to-noise ratio (SNR) at the photodetector output. If the statistics of the detected signal are Gaussian, a common assumption, then the bit-error rate (BER) performance of the system is predicted to reach a minimum that cannot be improved by increasing the received optical power. The actual performance, however, depends on the true detection noise statistics. We have measured the statistical distribution of the photoelectric current from a PIN photodiode illuminated by a spectrum-sliced, erbium-doped SFS. The histogram of the measurement data is best described by a negative binomial model for the corresponding photoelectron count with thermal light. Consequently, the BER performance of a spectrum-sliced WDMA system using such a superfluorescent fiber source is not limited by the SNR, a fundamentally different result from that predicted using the Gaussian assumption.
Functional and Structural Changes in the Kidney in the Early Stages of Obesity

The purpose of this study was to examine the histologic and functional changes that occur in the kidney in the early stages of obesity caused by a high-fat diet. Lean dogs (n = 8) were fed a standard kennel ration, and obese dogs (n = 8) were fed the standard kennel ration plus a supplement of cooked beef fat each day for 7 to 9 wk or 24 wk. Body weights were 58 +/- 5% greater and kidney weights were 31 +/- 7% greater in obese dogs, compared with the average values for lean dogs. Plasma renin activity and insulin concentrations were both 2.3-fold greater in obese dogs, compared with lean dogs. Obesity was associated with a mean arterial pressure increase of 12 +/- 3 mmHg, a 38 +/- 6% greater GFR, and a 61 +/- 7% higher renal plasma flow, compared with lean dogs. The glomerular Bowman's space area was significantly greater (+41 +/- 7%) in dogs fed the high-fat diet, compared with lean animals, mainly because of expansion of Bowman's capsule (+22 +/- 7%). There was also increased mesangial matrix and thickening of the glomerular and tubular basement membranes and the number of dividing cells (proliferating cell nuclear antigen-stained) per glomerulus was 36 +/- 8% greater in obese dogs, compared with lean dogs. There was also a trend for glomerular transforming growth factor-beta1 expression, as estimated by semiquantitative immunohistochemical analysis, to be elevated with the high-fat diet. Therefore, a high-fat diet caused increased arterial pressure, hyperinsulinemia, activation of the renin-angiotensin system, glomerular hyperfiltration, and structural changes in the kidney that may be the precursors of more severe glomerular injury associated with prolonged obesity.
Finite element analysis of the effect of an interphase on toughening of a particle-reinforced polymer composite

Abstract A numerical method was used to study the interaction between a crack and the filler phase in a particle-reinforced polymer composite. The simulation was achieved by implementing a progressive damage and failure material model and element-removal technique through finite element analysis, providing a framework for the quantitative prediction of the deformation and fracture response of the composite. The effect of an interphase on composite toughness was also studied. Results show that a thin and high strength interphase results in efficient stress transfer between particle and matrix and causes the crack to deflect and propagate within the matrix. Alternatively, a thick and low strength interphase results in crack propagation within the interphase layer, and crack-blunting. Further analysis of the effect of volume fraction and particle–particle interactions on fracture toughness as well as prediction of the fracture toughness can also be achieved within this framework.
Limb regeneration following the discontinuation of growth hormone therapy in the hypophysectomized newt, Notophthalmus viridescens.

Untreated adult newts do not undergo normal limb regeneration following hypohysectomy. A fibrocellular dermal barrier (cicatrix) atypically forms between the apical epithelium and the underlying mesenchymal tissues. Historically, continuous administration of growth hormone or of prolactin in combination with thyroxine restored regenerative capacity to these newts. In a previous investigation, we demonstrated that the initial effect of these two hormone treatments, when administered on alternate days to hypophysectomized newts beginning eight days post-amputation, was to facilitate the erosion of the fibrocellular barrier and establish the epithelial mesenchymal interface that is observed in a regenerating limb. The present investigation was designed to evaluate the necessity of continuous hormone therapy to maintain limb regeneration in hypophysectomized newts. One, two, or three injections of growth hormone or of prolactin in combination with thyroxine was administered on successive alternate days to hypophysectomized newts either immediately following limb amputation (ID) or beginning eight days post-amputation (DD). The ID and DD newts receiving one, two, or three injections of growth hormone showed evidence of regeneration to the digitiform stage by day 30 post-amputation, while those receiving prolactin and thyroxine underwent wound healing. While both hormone treatments initially promoted a dermis-free apical epithelium, only hypophysectomized newts that had received growth hormone were able to continue regenerating. We have, therefore, concluded that discontinuous growth hormone therapy is sufficient to initiate and maintain the conducive environment for limb regeneration to advanced stages in the hypophysectomized newt. While initiating this process, prolactin and thyroxine therapy on a discontinuous regime does not maintain regeneration. The direct and indirect role of growth hormone in supporting limb regeneration in normal and hypophysectomized newts is discussed.
Predictive validation of single-episode uncomplicated depression as a benign subtype of unipolar major depression.

OBJECTIVE: To evaluate the predictive validity of a proposed benign major depressive disorder (MDD) subtype, single-episode 'uncomplicated MDD', defined as MDD that remits within 6 months and lacks severe impairment, psychotic ideation, suicidal ideation, psychomotor retardation, and feeling worthless. METHOD: Using two-wave National Epidemiologic Survey on Alcohol and Related Conditions data, four groups differing in wave 1 lifetime MDD history (no history [n = 27 609]; single-episode uncomplicated [n = 418]; other single-episode [n = 1943]; multiple episode [n = 2473]) were evaluated for 3-year follow-up rates of major depressive episode (MDE), generalized anxiety disorder (GAD), and suicide attempt. RESULTS: Follow-up rates for no-MDD-history, single-episode uncomplicated MDD, other single-episode MDD, and multiple-episode MDD, respectively, were depressive episode 6.1%, 6.9%, 19.5%, 27.1%; GAD 2.7%, 4.3%, 7.8%, 11.2%; and suicide attempt 0.3%, 0.1%, 0.8%, 1.7%. For all validators, 3-year rates for single-episode uncomplicated cases were not significantly different from no-MDD-history rates, but significantly lower than both single- and multiple-episode other-MDD rates. Mild MDD, defined by having only five or six symptoms, did not yield similarly benign results; logistic regression showed 'uncomplicated' provides incremental validity over 'mild' in explaining validator rates. Validator differences were not explainable by treatment-rate differences. CONCLUSION: Single-episode uncomplicated MDD is a benign subtype lacking typical MDD negative sequelae. The planned DSM-5.1 revision should reinstitute an extended bereavement exclusion applied to all stressors. Language: en
Quorum Sensing on a Global Scale: Massive Numbers of Bioluminescent Bacteria Make Milky Seas

Many in the field would not have believed that luminous bacteria could be responsible for continuous and substantial light emission from the surface of the ocean extending over an area as large as the state of Connecticut and detectable from space. But in a recent paper in the Proceedings of the
Dynamic arc modeling of pollution flashover of insulators under DC voltage

A dynamic model that computes the flashover voltages of polluted insulators energized with DC voltage is presented. The salient feature of this model is that it takes into account the configuration of the insulator profile at every instant, which plays an important role in the flashover process of the DC polluted insulators. A number of practical insulator geometries have been studied, and the validity of the model is verified by comparing the computed results with the experimental results of previous researchers. >
Error floor elimination for DFT-based frequency estimators

Frequency estimation for a single-tone complex exponential signal is a classical and fundamental problem in many applications, such as communications, radar, and power. Most DFT-based frequency estimators reported in the literature exhibit an error floor at high SNR, due to their use of approximations to nonlinear equations. This effect is pronounced for short observation windows. In this paper, we propose two simple nonlinear equation solvers for eliminating this error floor. Simulations confirm the effectiveness of this proposed approach. We add to the literature of DFT-based estimators by proposing a frequency estimator for the case where a measured sequence is zero-padded by a factor of two.
Series-connected GaAs and Si IMPATT-diode chips: some new results

Gallium-arsenide Schottky low-high-low IMPATT-diode chips have been successfully combined in series. A maximum c.w. power output of 22.5 W has been repeatedly obtained in X-band by using six 4-W 0.2-mm-diameter mesa GaAs devices. After careful preselection of GaAs chips (yield ≃ 20%), the GaAs devices combined more readily than did silicon p+-n-n+ impatt chips.
A snubber cell for single-stage PFC with a boost type input current shaper and isolated dc/dc converter

This paper proposes a lossless snubber cell for all single-stage PFC with a boost type input current shaper and an isolated dc/dc converter. The single auxiliary switch of the snubber cell shares the same switching signal as the PFC main switch; both switches operate under soft switching way. Various stages of the switching cycle have been comprehensively analyzed to explain the operation principle of the soft switching transition. This soft switching technique reduces switching power loss and improves efficiency. The simulation results verify the practicable of the new snubber cell. 100W prototypes are built on the bi-flyback PFC converter and the BIFRED PFC converter; experimental waveforms match with simulation results.