cssi/SciSciGPT-SciSciNet huggingface dataset:
Melatonin inhibits in vitro serotonergic phase shifts of the suprachiasmatic circadian clock

The suprachiasmatic (SCN) circadian pacemaker generates 24 h rhythms of spontaneous neuronal activity when isolated in an acute brain slice preparation. The isolated pacemaker also retains its capacity to be reset, or phase-shifted by exogenous stimuli. For example, serotonin (5-HT) agonists advance the SCN pacemaker when applied during mid subjective day, while neuropeptide Y (NPY) agonists and melatonin advance the pacemaker when applied during late subjective day. Previous work has demonstrated interactions between NPY and 5-HT agonists, such that NPY can block 5-HTergic phase advances, while 5-HT agonists do not prevent NPY-induced advances. Due to a number of similarities in the actions of melatonin and NPY in the SCN, it seemed possible that melatonin and 5-HT might interact in the SCN as well. Therefore, in this study potential interactions between melatonin and 5-HT agonists were explored. Melatonin inhibited phase advances by the 5-HT agonist, (+)DPAT, and this inhibition was decreased by co-application of tetrodotoxin. Conversely, melatonin was unable to block phase advances by the cyclic AMP analog, 8BA-cAMP. Finally, neither 5-HT agonists nor 8BA-AMP were able to block melatonin-induced phase advances. These results demonstrate a clear interaction between melatonin and 5-HT in the SCN, and suggest that melatonin and NPY may play similar roles with respect to modulating the phase of the SCN circadian pacemaker in rats.
Ignition in nonpremixed counterflowing hydrogen versus heated air: Computational study with detailed chemistry

Abstract Forced ignition in counterflowing jets of N2-diluted H2 versus heated air has been investigated over a wide range of temperature, pressure, and strain rate by numerical modeling with detailed chemistry and transport. Ignition temperatures calculated at constant strain rates are seen to exhibit a Z-shaped pressure dependence similar to that observed in explosion limits of homogeneous H2/air mixtures. As with the corresponding explosion limits, the first and second ignition limits are governed by the competition for hydrogen radicals between chain branching (H + O2 → O + OH) and termination (H + O2 + M → HO2 + M) pathways, and the third ignition limit involves additional propagation (2HO2 → H2O2 + O2 → 2OH + O2) and branching (HO2 + H2 → H2O2 + H → 2OH + H) pathways that compete with chain termination. Ignition in this inhomogeneous, diffusive system is found to involve a spatially localized ignition “kernel,” identified as the region near the point of maximum temperature where the rate of hydrogen radical chain branching is maximized. Mass transport of radicals out of the ignition kernel affects the ignition process by competing with chemical reactions within the kernel, particularly in the first and third limits where the dominant ignition chemistry is relatively slow. Ignition temperatures in these limits are found to be much more sensitive to aerodynamic straining than in the second limit. By controlling the width of the ignition kernel and thus the characteristic residence time of key radicals within it, the strain rate is found to determine the dominant chemistry and the relevant ignition limit at any given pressure.
Hormonal regulation of lactate dehydrogenase-A through activation of protein kinase C pathways in MCF-7 breast cancer cells

Lactate dehydrogenase A (LDH-A) is hormonally regulated in rodents, and increased expression of LDH-A is observed during mammary gland tumorigenesis. The mechanisms of hormonal regulation of LDH-A were investigated using a series of deletion and mutant constructs derived from the rat LDH-A gene promoter. Results of these studies show that constructs containing the -92 to -37 region of the LDH-A promoter are important for basal and E2-induced transactivation, and mutation of the consensus CRE motif within this region results in significant loss of basal activity and hormone-responsiveness. Gel mobility shift assays using nuclear extracts from MCF-7 cells show that both CREB and ATF-1 interact with the CRE. Studies with kinase inhibitors show that E2-induced activation of this CRE is dependent on protein kinase C, and these data indicate that LDH-A is induced through a non-genomic pathway of estrogen action.
Fabrication of {198Au0} radioactive composite nanodevices and their use for nanobrachytherapy

Abstract We describe the simple fabrication of poly({ 198 Au}) radioactive gold-dendrimer composite nanodevices in distinct sizes (diameter between 10 nm and 29 nm) for targeted radiopharmaceutical dose delivery to tumors in vivo. Irradiation of aqueous solutions of 197 Au containing poly(amidoamine) dendrimer tetrachloroaurate salts or { 197 Au 0 } gold-dendrimer nanocomposites in a nuclear reactor resulted in the formation of positively charged and soluble poly{ 198 Au 0 } radioactive composite nanodevices (CNDs). A mouse melanoma tumor model was used to test whether the poly{ 198 Au 0 } CNDs can deliver a therapeutic dose. A single intratumoral injection of poly{ 198 Au 0 } d=22nm CNDs in phosphate-buffered saline delivering a dose of 74 μCi resulted after 8 days in a statistically significant 45% reduction in tumor volume, when compared with untreated groups and those injected with the "cold" nanodevice. No clinical toxicity was observed during the experiments. This study provides the first proof of principle that radioactive CNDs can deliver therapeutic doses to tumors.
Crashworthiness Analysis and Optimization of Thin-Walled Square Tube with Pyramidal Ripples Based on Mechanics Properties

Thin-walled structure absorbs most impact kinetic energy during collision accident,and they are widely used as energy-absorbing element. In order to improve crashworthiness of them, regular pyramidal ripple is added on the thin-walled square tube’s surface. Explicit finite element technology is applied to simulate the behavior of the tube under axial impact load. Simulation data was delt with by Response Surface Method to form a function of variables and response,and the new structure was optimized. Research results show that, the thin-walled square tube with pyramidal ripples can improve controllable of structure deformation obviously and Optimized structure can absorb and dissipate much more impact kinetic energy.
Being fat versus thinking fat: Relationships with body image, eating behaviors, and well-being

The majority of females and about one-fourth of men who are objectively normal weight perceive themselves to be overweight. The purpose of this investigation was to examine specific psychological differences between persons as a function of their weight self-classifications with actual weight controlled and vice versa. Subjects were sampled from a nationwide survey. Study 1 compared normal-weight subjects self-classified as overweight with age- and weight-matched subjects who were self-classified as normal weight (n's = 198 females and 130 males) on facets of body image, eating/dieting behaviors, and psychosocial well-being. Relative to controls, self-classified overweight subjects of both sexes reported a less adaptive body image in several respects, and more frequent binge eating and dietary restraint to lose weight, as well as poorer well-being. Study 2 included only self-classified overweight subjects and compared those who were actually overweight with normal-weight controls (n's = 112 females and 106 males). Actually being overweight produced only a few group differences, particularly for females, beyond those of the overweight self-classification. Research directions and clinical implications are discussed.
A Review of Thermal Effects in Hydrodynamic Bearings Part I: Slider and Thrust Bearings

An extensive survey of the papers pertaining to thermal effects in hydrodynamic bearings, particularly the slider/thrust bearings, is presented with a summary of the important contributions of leading researchers and designers. Presented at the 41st Annual Meeting in Toronto, Ontario, Canada May 12–15, 1986
Multinationality of US corporations: the auditing implications

Explains the auditing problems encountered by multinational companies under the US Foreign Corrupt Practices Act and the Regulation of Technology Transfers and the complications of resource allocation in countries with different cultures to the USA. Highlights currency fluctuations, human resources and environmental audit. Lists some of the differences between US and foreign auditor independence and auditing standards. Lays down the requirements for an auditor on foreign assignment.
Observations of subtidal and tidal flow in the Rı́o de la Plata Estuary

Abstract We present the first measurements obtained with a combination of a towed acoustic Doppler current profiler (ADCP) and a conductivity–temperature–depth (CTD) recorder in the Rio de la Plata Estuary. Subtidal and tidal flows are described for austral winter and summer conditions. Data were collected at three transects 15 km long for 25 h during August 11–17, 1999 (austral winter) and February 2–6, 2000 (austral summer) at the transition zone between fresh and brackish waters. Two transects covered cross-estuary tracks off the northern and southern coastlines of the estuary. A central transect was oriented along the estuarine axis near the up-stream limit of saltwater intrusion. The observations indicated that the dominant dynamical processes were different at each of the transects sampled. The most relevant feature was the dominance of tidal currents in the southern side of the estuary and the lesser role they played in the northern side (Uruguayan coast). The pressure gradient produced by the freshwater outflow was modified differently at the southern than at the northern sides of the estuary. At the southern side tidal mixing, from strong tidal currents, allowed the development of gravitational circulation. At the northern side weak tidal currents allowed modifications by ambient forcing and surface stresses, consistent with theoretical results of surface-advected freshwater outflows.
Malpractice carrier underwrites Fundamentals of Laparoscopic Surgery training and testing: a benchmark for patient safety.

Fundamentals of Laparoscopic Surgery (FLS) is a validated program developed by the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) to educate and assess competency in minimally invasive surgery (MIS). This study reports the first malpractice carrier–sponsored FLS course for surgeons in practice underwritten by the Controlled Risk Insurance Company of Harvard’s Risk Management Foundation (CRICO/RMF). The study investigated the participating surgeons’ pattern of MIS skills acquisition, subjective laparoscopic comfort level, operative activity, and perception of the FLS role in surgical education, credentialing, and patient safety. A 1-day postgraduate continuous medical education (CME) course consisted of didactic presentations of the leading MIS faculty, proctored FLS hands-on training, psychomotor testing, and cognitive computer-based examination. Voluntary anonymous pre- and postcourse surveys were distributed to the participants at registration and at completion of both the didactic teaching and the skills modules of the program. The course was attended by 37 practicing surgeons in the Harvard system, and 86% of the survey forms were returned. The major driving forces for attending the course were directive from the chief/chairman (50%), improvement in MIS didactic knowledge (56%), and the belief that FLS would become a standard such as advanced trauma life support (ATLS), advanced cardiac life support (ACLS), or the like (53%). Surgeons reported that the FLS exam content was appropriate (Likert 4.41 ± 0.91) and that mastery of the course material would improve safety (Likert 4.13 ± 0.79) and technical knowledge of MIS (Likert 4.03 ± 1.00). This unique cooperative effort between a liability carrier, a professional surgical society, and proactive surgeons should be considered a model for advancing competency and patient safety. The survey results indicate a positive view of FLS in surgical training, safety, and MIS education.
Preparation and reactivity of bridge-substituted bicyclo[3.2.1]octyl and bicyclo[3.3.1]nonyl toluenesulfonates

Abstract Endo- and exo-bicyclo[3.2.1]octyl-8-tosylate (III and IV) and bicyclo[3.3.1]nonyl-9-tosylate (V) have been prepared by a novel synthetic sequence. In acetolysis, the relative rates are: III, 7·8 × 10−5; IV, 6·1 × 10−1; V, 3·0; for comparison, the rate of norbornyl-7-tosylate (I) is 9·1 × 10−8, and that of cyclohexyl tosylate (II) is 1·00. The solvolyses of IV and V are anchimerically accelerated. V is shown to undergo ion-pair return during solvolysis to cis-trans-hydrindyl-4-tosylate (XXIII). The relatively low rates of acetolysis of III and I are a result of internal angle strain at the carbon atom bearing the leaving group.
Quantitation of lung sealing in the survival swine model.

Abstract Purpose Small intercostal spaces and limited pleural space significantly limits the use of 12-mm stapling devices in pediatric thoracoscopic surgery. The goal of this study was to compare sealing of lung tissue by the 5-mm Ligasure (Valley Lab, Boulder, CO) device to a standard 12-mm Endo-GIA stapler (US Surgical, Norwalk, CT). Methods Institutional Animal Care and Use Committee (IACUC) approval was obtained (#A3-02). Sixteen 10-kg female swine were divided between 2 survival surgical groups. Lung biopsy sections of the lingula were taken by 2 methods: group A, left anterolateral thoracotomy employing a 12-mm Endo-GIA stapler and group B, left thoracoscopy employing the Ligasure 5-mm instrument. After a 7-day survival period, lung burst pressures were measured by flow-controlled insufflation into the trachea. Results Burst pressure measurement reflects the first air leak. By Student's t test analysis there were no statistically significant differences between the burst pressures, biopsy weights, or operating times. Fifty percent (4 of 8) of the animals in group A (Endo-GIA), and 50% (4 of 8) of the animals in group B (Ligasure) developed the first air leak in the nonoperative lung. Two animals, one from each group, had evidence of intrapleural infections at the time of necropsy. These were asymptomatic and did not appear to affect burst pressure measurement. Conclusions After 7 days of healing, lung biopsy sites created with both the Ligasure and the Endo-GIA stapler have burst strengths equal to or greater than that of normal lung tissue in the swine survival model.
Squamoid cystosis of pancreatic ducts: A variant of a newly-described cystic lesion, with evidence for an obstructive etiology

We describe a 40-year-old man who was found to have a cystic mass in the pancreatic tail during workup for weight loss and abdominal discomfort. Although computed tomography scan showed a single cyst associated with dilatation of the main pancreatic duct, gross and histologic examination of the distal pancreatectomy specimen actually revealed a central cyst that was surrounded by multiple smaller cystic spaces. This distinctive appearance was formed from extensive cystic dilatation and squamous metaplasia of the native pancreatic duct system. Further, a traumatic neuroma was discovered near the junction between normal and abnormal parenchyma. We believe that this case represents a variant of the newly-described squamoid cyst of pancreatic ducts which we term squamoid cystosis of pancreatic ducts. The presence of chronic pancreatitis and a traumatic neuroma supports the hypothesis that squamoid cysts are non-neoplastic lesions arising from prior duct obstruction.
Near-Infrared Laser-Induced Photothermal Coloration in WO3·H2O Nanoflakes

The structure and chromic properties of WO3·H2O nanoflakes have been investigated in situ by Raman spectroscopy and optical transmission under 785-nm laser irradiation with different powers. At a small power below 48 mW, the characteristic stretching vibrations of orthorhombic WO3·H2O at ν1 ≈ 650 cm-1 (W6+−O) and ν2 ≈ 947 cm-1 (terminal W6+−O) are observed, and their respective peak intensities, along with optical transmission, decay monotonically with irradiation time. At high-power irradiation (>48 mW), the Raman peaks at ν1 and ν2 decrease rapidly, and two new W6+−O stretching vibrations at ν3 ≈ 710 cm-1 and ν4 ≈ 805 cm-1, ascribed to monoclinic WO3, appear. At the same time, a photoinduced color change occurs rapidly, accompanied by a subsequent slow oxidation process, as reflected in optical transmission. The change of the Raman peaks' intensities with the irradiation time is consistent with the change of the optical transmission. Heat transfer analysis and the annealing experiment show that the colo...
Palmitic acid induces production of proinflammatory cytokine interleukin-8 from hepatocytes.

Obesity and the metabolic syndrome are closely correlated with hepatic steatosis. Simple hepatic steatosis in nonalcoholic fatty liver disease can progress to nonalcoholic steatohepatitis (NASH), which can be a precursor to more serious liver diseases, such as cirrhosis and hepatocellular carcinoma. The pathogenic mechanisms underlying progression of steatosis to NASH remain unclear; however, inflammation, proinflammatory cytokines, and oxidative stress have been postulated to play key roles. We previously reported that patients with NASH have elevated serum levels of proinflammatory cytokines, such as interleukin-8 (IL-8), which are likely to contribute to hepatic injury. This study specifically examines the effect of hepatic steatosis on IL-8 production. We induced lipid accumulation in hepatocytes (HepG2, rat primary hepatocytes, and human primary hepatocytes) by exposing them to pathophysiologically relevant concentrations of palmitic acid to simulate the excessive influx of fatty acids into hepatocytes. Significant fat accumulation was documented morphologically by Oil Red O staining in cells exposed to palmitic acid, and it was accompanied by an increase in intracellular triglyceride levels. Importantly, palmitic acid was found to induce significantly elevated levels of biologically active neutrophil chemoattractant, IL-8, from steatotic hepatocytes. Incubation of the cells with palmitate led to increased IL-8 gene expression and secretion (both mRNA and protein) through mechanisms involving activation of nuclear factor kappaB (NF-κB) and c-Jun N-terminal kinase/activator protein-1. Conclusion: These data demonstrate for the first time that lipid accumulation in hepatocytes can stimulate IL-8 production, thereby potentially contributing to hepatic inflammation and consequent liver injury. (HEPATOLOGY 2007.)
Advising Patients with Pulmonary Diseases on Air Travel

Excerpt Patients with diverse pulmonary disorders, with or without significant hypoxemia at ground level, have many opportunities for increased mobility and travel. These have developed from recent...
"You Gotta Reach ‘Em": An African American Teacher"s Multiple Literacies Approach

Teachers who utilize a multiple literacies approach to language instruction provide opportunities for students from culturally and linguistically diverse backgrounds to become more successful learners. A multiple literacies approach fosters an atmosphere of participation that allows students to tap into the language resources and cultural knowledge of their home communities and engage in meaningful learning. Equally important, a multiple literacies instructional approach helps students from culturally and linguistically diverse backgrounds, such as African American Language speakers, acquire standard language without sacrificing their identities.
Numerical Simulation of the Flow of Gases in a Large-Scale Electroslag Furnace

This paper reports a CFD modeling study on the flow of gases in an electroslag furnace during Protective Gas Electroslag Remelting(PESR) process by a commercial code FLUENT. The Realizable k−e turbulence model, Do radiation model and Mixture model are amply used in FLUENT code to compute the flow of gases in the furnace under different argon gas flow, and the influence of argon gas flow on air volume fraction in the furnace is obtained. Finally, a suited suggestion on argon gas flow during PESR process is presented.
Prevalence and severity of mitral regurgitation in the mitral valve prolapse syndrome: a Doppler echocardiographic study of 80 patients.

Doppler echocardiography was performed in 80 consecutive patients (22 men, 58 women), aged 38 ± 16 years, who had mitral valve prolapse diagnosed by two-dimensional echocardiography. Of the 80 patients, 16 (20%) were asymptomatic and 11 (14%) had a normal physical examination (no click or murmur). The M-mode echo, cardiogram was negative for mitral valve prolapse in 11 patients (14%) and equivocal or nondiagnostic in 19 patients (24%). Mitral regurgitation was evaluated using pulsed mode Doppler echocardiography and was quantified by the mapping technique as minimal or mild when a holosystolic regurgitant jet was recorded just below the mitral valve into the left atrium, and as moderate or severe when the jet was detected at the mid- or distal left atrium. Mitral regurgitation was found in 55 (69%) of the 80 patients and it was minimal or mild in 47 patients (59%) and moderate or severe in 8 (10%). In 20 (36%) of the 55 patients with Mitral regurgitation by Doppler technique, a systolic murmur was not detected and each of the 20 had only mild mitral regurgitation. Left atrial and left ventricular size were significantly smaller in patients with mild or no regurgitation as compared with the eight patients with moderate or severe regurgitation. These eight patients were all men (six over 50 years of age) who usually presented with dyspnea and a holosystolic murmur; the Mitral valve prolapse was holosystolic by M-mode and involved both leaflets by twodimensional echocardiography. In conclusion: 1) Mitral regurgitation as assessed by Doppler echocardiography was common in patients with mitral valve prolapse, but was usually mild and not always associated with an audible murmur. 2) Significant Mitral regurgitation was rare (10%) and usually occurred in men with Mitral valve prolapse who were more than 50 years old.
Fusion of modal strain energy differences for localization of damage

The fusion of multiple modal strain energy differences is proposed for the detection of damage at single and multiple locations. The approaches assume the existence of several modal shapes of the structure in the undamaged and damaged states. Modal curvatures obtained through iterative high- order spline fits of the shapes permit the determination of the modal strain energy content of the structure in both states. Locations with increases in the modal strain energy between the undamaged and damaged structure are indicative of possible damage. The damage indications resulting from multiple modes are fused according to three rules: (1) an Average Standard Norm, (2) a union of probability mass functions and (3) a weighted intersection of the probabilities that the strain energy are greater than zero. the third rule requires knowledge of the statistics of the modal shape measurements. While not strictly adhering to the classical data fusion methodologies such as, Dempster-Shafer or Bayesian, the combination of information at the probabilistic level yields result that are consistent with those expected in a formal data fusion formulation. The fusion algorithms for the location of damage are tested using five modal shapes obtained from aluminum beams in undamaged and damaged states. One and two locations at different damage magnitudes are considered. The results indicate that the last two approaches are superior to the standard norm method.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Simulation of polyethylene thin films on a high coordination lattice

We present the results of some film simulations of polyethylene (PE) on a coarse-grained lattice, which is termed as the second nearest neighbor diamond (2nnd) lattice. Monte Carlo simulations of PE melts have been performed on the 2nnd lattice by including short- and long-range interactions. Films can be obtained from equilibrated bulk snapshots by increasing one periodic side to infinity. The presence of attractive long-range interactions besides the repulsive ones gives a cohesive nature to the film. PE films, which contain up to 108 chains of C99 and have thicknesses of more than 100 A between the two surfaces, can be produced and equilibrated on the 2nnd lattice. In these films, the density profiles are hyperbolic, with end beads being more abundant than the middle beads at the interface. There are orientational preferences at the interface on the scale of individual bonds and whole chains. The center of mass distribution of the chains exhibits oscillatory behavior. A comparison of films with differe...
DIPA (decompression-inducible platelet aggregation) and hemostasis: vascular occlusion and its prevention, in the web of the frog's foot

It is reported here that vascular obstruction is inducible in blood vessels in the web of the frog's foot; the frog had been decompressed for 3 hours at 253 torr (the barometric pressure at the summit of Mt. Everest). The blood flow was reestablished within an hour of recompression at 760 torr. It is reported additionally, that the drug piracetam can block decompression-inducible platelet aggregation (DIPA) and consequently vascular obstruction
Analysis of nucleolar organizing regions in parents of trisomic spontaneous abortions.

Nucleolar organizing region (NOR) variants of parents of karyotyped spontaneous abortions were examined to fest the hypothesis that double NORs are important in the genesis of acrocentric trisomies. We were unable to detect any significant difference in the frequency or types of NOR variants between parents of acrocentric trisomies and parents of other types of spontaneous abortions, nor did we identify a double NOR in either group. Thus, it seems unlikely that double NORs are of major significance in the etiology of acrocentric trisomies.
Modeling and solving physical problems

Abstract Generic operator equations allowing multidimensional operators are solved by a decomposition method allowing solution of nonlinear and/or stochastic partial differential equations by accurate and convenient approximation. Green's functions for complicated ordinary or partial differential linear equations are similarly determinable.
Executive functioning among young people in relation to alcohol use.

PURPOSE OF REVIEW This article reviews recent findings regarding neurobehavioral factors which may be associated with risk for alcohol misuse, as well as those which may occur as a result of alcohol misuse during adolescence and emerging adulthood. RECENT FINDINGS Current research extends previous findings by engaging multiple assessment methods and integrating behavioral and imaging technologies. These efforts reinforce previous findings regarding alcohol-related changes in macrostructure while demonstrating alterations in brain connectivity previously underappreciated. Longitudinal work now being reported suggests problem use during adolescence may be associated with persistent neurobehavioral aberrations. SUMMARY For many years, little attention was directed to the neurobehavioral consequences of alcohol use across adolescence and emerging adulthood or to the neurobehavioral factors which might predispose youth to alcohol misuse. Recent work provides critical insights regarding the underpinnings of the deficits in executive function often observed in those at risk for alcohol dependence and those who develop alcohol use disorders. These studies suggest that, even when behavioral deficits are not evident, changes in brain connectivity and microstructure may be observed. Programmatic, longitudinal research must be conducted to determine the relevance of these alterations to use trajectories and long-term adaptation.
Computation of Wind Flow around a Tall Building and the Large–Scale Vortex Structure

Abstract A numerical study of three-dimensional wind flow around a tall building is presented in this paper. The solution is obtained by solving weakly compressible flow equations, along with Smagorinsky's subgrid-scale turbulent model. The numerical scheme is based on MacCormack's predictor-corrector explicit finite volume method. First, the numerical model was verified by testing a shear flow around surface-mounted cube, then a detailed study was carried out for a shear flow around a taller building model (width:length:height = 1:0.889:4.667). The main task of this paper is to explore the large-scale vortex structure and the unsteady behavior of flow around a tall building, which are still not well understood.
Preliminary performance and life evaluation of a 2-kW arcjet

The first results of a program to expand the operational envelope of low-power arcjets to higher specific impulse and power levels are presented. The performance of a kW-class laboratory model arcjet thruster was characterized at three mass flow rates of a 2:1 mixture of hydrogen and nitrogen at power levels ranging from 1.0 to 2.0 kW. This same thruster was then operated for a total of 300 h at a specific impulse and power level of 550 s and 2.0 kW, respectively, in three continuous 100-h sessions. Thruster operation during the three test segments was stable, and no measurable performance degradation was observed during the test series. Substantial cathode erosion was observed during an inspection following the second 100-h test segment. Most notable was the migration of material from the center of the cathode tip to a ring around a large crater. The anode sustained no significant damage during the endurance test segments. Some difficulty was encountered during start-up after disassembly and inspection following the second 100-h test segment, which caused constrictor erosion. This resulted in a reduced flow restriction and arc chamber pressure, which in turn caused a reduction in the arc impedance.
Recombination rates for single colloidal quantum dots near a smooth metal film.

This paper presents experimental distributions of recombination rates for excitons in individual CdSe–ZnS core–shell quantum dots separated from a smooth gold film by a nanometre-scale dielectric layer. By measuring emission kinetics as a function of time, we obtain intrinsic recombination rates for single quantum dots. The distribution of recombination rates broadens and its maximum value increases as the separation between the dots and the metal decreases. The results agree with a semiclassical model that takes into account the randomly oriented two-dimensional dipole moments of the quantum dots.
Tumor necrosis factor in alcohol enhanced endotoxin liver injury.

Endotoxin administration causes liver injury. Patients with alcoholic liver disease frequently have portal vein and systemic endotoxemia, and some investigators have suggested that endotoxin plays an etiologic role in alcoholic liver injury. Many of the metabolic effects of endotoxin are mediated by the cytokine tumor necrosis factor (TNF). It was the purpose of this study to determine whether TNF plays a role in ethanol-enhanced endotoxin liver injury. Rats were fed either a diet in which 36% of the calories were from ethanol or an isocaloric control diet. After 6 weeks, groups of 10 rats were intravenously injected with either saline, 1 mg/kg endotoxin, or 30 μg/kg of a prostaglandin E1 (PGE1) analogue + 1 mg/kg endotoxin 24 hr prior to sacrifice. Ethanol/endotoxin-treated rats had significantly higher liver enzyme levels (ALT 1064 ± 355 IU/liter, AST 2024 ± 515 IU/liter) compared with isocaloric/endotoxin controls (ALT 237 ± 54 IU/liter, AST 602 ± 80 IU/liter). Ethanol/endotoxin rats also had significantly higher peak serum TNF concentrations (992 ± 200 units/ml) compared with isocaloric/endotoxin controls (344 ± 96 units/ml). Pretreatment of ethanol/endotoxin rats with PGE1 caused significant attenuation of liver injury (ALT: 267 ± 64 IU/liter, AST 612 ± 77 IU/liter) and a diminished serum TNF response. In contrast to chronic ethanol administration, acute gavage with 2 mg/kg ethanol (30% w/v) followed by intravenous injection of 2 mg/ kg endotoxin produced significantly lower peak serum TNF concentrations (401 ± 76 units/ml) than gavage with distilled water (1152 ± 208 units/ml). We conclude that chronic ethanol feeding enhances endotoxin-stimulated peak serum TNF concentrations, endotoxin liver injury, and pretreatment with the TNF synthesis inhibitor PGE1 attenuates this liver injury. Furthermore, acute and chronic alcohol feeding appear to have opposite effects on endotoxin stimulated serum TNF levels.
Diffusion of V48 and Fe59 in vanadium

Measurements have been made of tracer diffusion coefficients of V48 and Fe59 in single crystals of vanadium over the temperature range 840–1830°C. The V48 results show temperature dependent diffusion characteristics that are represented by activation energies of 94 kcals/mole above 1356°C and 72 kcals/mole below this temperature, and those for Fe59 by an activation energy of 70 kcals/mole in the temperature range 840–1170°C. No single explanation of these results is offered but the low temperature data appear to be consistent with the operation of a vacancy mechanism of diffusion. Other results associated with grain boundary diffusion, surface effects and dislocation diffusion are presented and briefly discussed.
55Fe in Supernova 1987A

Observations of newly synthesized radioactive nuclei have provided a wealth of information about the extensively observed supernova 1987A. We add another such study, searching Chandra X-ray spectra of SN 1987A for evidence of 5.9 keV Mn Kα line emission due to the decay of radioactive 55Fe. This isotope is synthesized in explosive silicon burning and in normal freezeout of nuclear statistical equilibrium, mostly as 55Co, in the inner ejecta of core-collapse supernovae. The X-rays from the decay in these regions escape only after 10-20 yr of expansion, depending on the extent of mixing of core material outward in mass. Otherwise generally successful models of SN 1987A predict fluxes at 5.9 keV detectable by Chandra. However, in 400 ks of Chandra ACIS data, we find no evidence for this line emission, with the mean line flux ≤3 × 10-7 cm-2 s-1. We consider the implications for atomic mass A = 55 nucleosynthesis and for the kinematics and mixing of SN 1987A.
Ellipsometric Metrology Of Ultrathin Films: Dual Angle Of Incidence

Single angle of incidence ellipsometrie measurements have been extended to dual angle measurements on our newly constructed multi-method precision ellipsometer in order to better determine the optical constants of a substrate. Following the measurement error analysis that was prescribed in an earlier paper for single angle of incidence and fixed wavelength measurements, the results for dual angle of incidence are presented here. Using an Explicit Error Analysis (EEA) method, involving the differentials of the measurable optical constants of the surface, it is possible to find a well-defined pair of incident angles to perform the measurement. Without a measurement error analysis, there would be no way of knowing what the absolute measurement uncertainty is or which angles of incidence could provide optimum measurement conditions. As in the case of single angle of incidence measurement where we were able to select an optimum angle of incidence to assure the highest measurement accuracy, the dual angle of incidence measurement also predicts optimum angles of incidence. It was found that in the case of single angle of incidence ellipsometry the principal angle of incidence can sharply define the optimum angle for measuring bare substrates and very thin films on a substrate. Likewise, for the dual angle of incidence measurement, there can also be two sharply defined angles for certain sample surface models. Here we present a dual angle ellipsometric measurement of the real part of the refractive index of a silicon substrate at the wavelength of 632.8 nm. A silicon dioxide film thickness between 125 and 150 nm and the two angles of incidence, 68 and 72 deg, optimized this measurement. The real part of the refractive index of the silicon substrate was found to be 3.865 ± 0.001.
Model for Locating Fluids' Contracts in Petroleum Reservoirs

Direct determination of the gas-water contact (GWC) or the oil-water contact (OWC) in new wells from geophysical logs, core analysis data and/or whole core inspection is often difficult. Rapidly changing reservoir quality in the interval of interest or gradually changing saturation profiles in the vicinity of the contact can make the determination of the GWC or OWC difficult. This paper presents a model for the accurate placement of the GWC or OWC. The input data are water saturations at various well depths as interpreted from induction logs and the average residual oil saturation. When available, permeability and porosity values from core analysis may improve the result. Using a power-law equation or a Langmuir isotherm-type equation to represent the capillary pressure saturation relationship, the GWC or OWC is expressed as a function of water saturation and well depth. A nonlinear optimization technique is then used to determine the GWC or OWC. The applicability of this model is demonstrated with a field example. The calculated OWC values from all variations of the model fall within 4 feet of the actual OWC value. This model can only be applied in an oil or gas well where an equilibrium capillary curve and a hydrocarbon-watermore » contact occur.« less
Multilocus epistasis, linkage, and genetic variance in breeding populations with few parents.

In a previous study of maize (Zea mays L.) populations formed from few parents, we found that estimates of genetic variances were inconsistent with a simple additive genetic model. Our objective in the current study was to determine how multilocus epistasis and linkage affect the loss of genetic variance in populations created from a small number of parents (N). In simulation experiments, F2 individuals from the same single cross were intermated to form progeny populations from N = 1, 2, 4, and 8 parents. Additive gene effects and metabolic flux epistasis due to L = 10, 50, and 100 loci were modeled. For additive, additive-with-linkage, epistatic, and epistasis-with-linkage models, we estimated the ratio between total genetic variance in the progeny population (VN) and base population (VB) as well as the 95th (Δ95%) and 75th (Δ75%) percentile differences between the estimated VN/VB and the VN/VB expected for the additive model. The mean VN/VB ratio was lower under epistasis than under additivity, indicating that metabolic flux epistasis hastens the decline in genetic variance due to small N. In contrast, Δ95% was higher with epistasis than with additivity across the different levels of N and L. Linkage had little effect on the mean VN/VB, whereas it increased Δ95% and Δ75% under both additivity and epistasis. Smaller N and L led to higher VN/VB particularly when epistasis was present. Overall, the results indicated that while metabolic flux epistasis led to a faster average decline in genetic variance, it also led to greater variability in this decline to the point that VN/VB was larger than expected in many populations.
Regioselective hydrosilations. IV. The synthesis and polymerization of monomers containing epoxy and alkoxysilane groups

Using rhodium and platinum catalyzed regioselective hydrosilation, a series of α-hydrogen-ω-epoxy silane and siloxane compounds have been prepared in good yields. These intermediates have been further condensed with vinyltrimethoxysilane in subsequent hydrosilation reactions to prepare an interesting new class of ambifunctional monomers containing both epoxy and trimethoxysilane groups. It was further shown that these same compounds could be synthesized by a simplified “one-pot” two-step procedure. An investigation of the simultaneous cationic ring-opening polymerization of the epoxy groups and the acid-catalyzed condensation of the trimethoxysilyl groups was carried out. © 1993 John Wiley & Sons, Inc.
A thermometer-like mismatch shaping technique with minimum element transition activity for multibit ΔΣ DACs

This brief presents a novel mismatch shaping technique for multibit delta-sigma digital-to-analog converters (DACs). It uses the intrinsic quantization noise to randomize the element selection. Different from most existing mismatch shaping techniques that increase the element transition activity, the proposed technique keeps the same transition rate as that for the basic thermometer coding scheme. As a result, it produces much lower intersymbol interference (ISI)-induced distortions. Moreover, it does not produce tones and can high-pass shape the mismatch errors, unlike thermometer coding that produces large distortions due to static mismatch. An efficient hardware implementation based on the vector-quantizer mismatch shaping framework is also presented. Simulations show that the proposed technique can significantly improve DAC linearity in the presence of both ISI and mismatch errors.
Computer analysis of two-dimensional gels: Automatic matching

A program which automatically mathches the spot patterns resolved on two-dimensional gel electrophoretograms is described. The program does not require handmatched, landmark matches for initial alignment of the spot patterns. The matching algorithm is based on a hierarchical nearest neighbor analysis. Starting with the most intense spots in the two films, the program determines if spots are equivalent by attempting to match a list of all nearby spots (a “cluster”) from each film. “Clusters” are considered to be aligned if there is a low probability that the pairing of spots between them is due to a random process. The match is further tested by requiring that secondary clusters (i. e. those clusters that surround the spots matched between the central clusters) can also be aligned. Pairings found by cluster matching are checked for consistency and matches that are out of alignment with the majority of other mathces are eliminated. Finally, the program tries to match the remaining spots by mapping the coordinates of an unmatched spot in one gel into the coordinate system of the other using the matched spots in the cluster as landmarks. The formulas used for the transformation allow for localized rotation and stretching of the coordinate systems. The accuracy and robustness of the program are discussed. If high quality gels are used, the program will find, on average, 95% of the spots that are mathcable between the gels, and requires about 4.3 seconds per mathch. Most of the errors are found at the extreme edges of the gels.
Mice with Disseminated Candidiasis Die of Progressive Sepsis

Background Candida species are among the most common etiologies of nosocomial bloodstream infections, causing a mortality of >40%. The murine model of hematogenously disseminated candidiasis is the standard for investigating both the activity of antifungal agents and the pathogenesis of this disease. However, despite decades of use, little is known about the physiological characteristics of the host in this model, and the cause of death remains unclear. Methods Using i-STAT technology, we measured blood chemistry and hemodynamic parameters to define host physiological characteristics during murine disseminated candidiasis. Results Mice with hematogenously disseminated candidiasis died of progressive sepsis, as manifested by worsening hypotension, tachycardia, and hypothermia. The mice developed metabolic acidosis, as well as profound acidemia and hypoglycemia. They also developed renal insufficiency, which became severe only shortly before death. Kidney fungal burden was correlated with severity of renal failure and systemic acidosis. The presence of significant weight loss, hypotension, or hypothermia was predictive of imminent death. Conclusions These findings indicate that the murine model of hematogenously disseminated candidiasis accurately recapitulates the progressive sepsis seen during severe clinical cases. The results underscore the validity of the model for study of the pathophysiological aspects of this disease, as well as for the evaluation of antifungal drug efficacy.
Unsupervised image segmentation utilizing penalized inverse expectation maximization algorithm

This work is on accurate segmentation of images using local image characteristics. An appropriate Gabor filter with customized size, orientation, frequency and phase for each pixel is selected to measure the image features. A new image property called phase divergence is introduced to select the filter size. Brightness, color, texture and position features are extracted for each pixel and the joint distribution of these pixel features is modeled by a mixture of Gaussians. A new version of the expectation maximization (EM) algorithm called Penalized Inverse EM (PIEM) is formulated for estimating the parameters of the mixture of Gaussians model. Furthermore, we determine the number of models that best suits the image based on Schwarz criterion. The performance on the Berkeley segmentation benchmark proves the efficacy and accuracy of the proposed method.
Emergence of Mammalian Cell-Adapted Vesicular Stomatitis Virus from Persistent Infections of Insect Vector Cells

Arboviruses (arthropod-borne viruses) represent quintessential generalists, with the ability to infect and perform well in multiple hosts. However, antagonistic pleiotropy imposed a cost during the adaptation to persistent replication of vesicular stomatitis virus in sand fly cells and resulted in strains that initially replicated poorly in hamster cells, even when the virus was allowed to replicate periodically in the latter. Once a debilitated strain started replicating continuously in mammalian cells, fitness increased significantly. Fitness recovery did not entail back mutations or compensatory mutations, but instead, we observed the replacement of persistence-adapted genomes by mammalian cell-adapted strains with a full set of new, unrelated sequence changes. These mammalian cell-adapted genomes were present at low frequencies in the populations with a history of persistence for up to a year and quickly became dominant during mammalian infection, but coexistence was not stable in the long term. Periodic acute replication in mammalian cells likely contributed to extending the survival of minority genomes, but these genomes were also found in strictly persistent populations.
CALL OPTION VALUATION FOR DISCRETE NORMAL MIXTURES

In this study a mixture call option pricing model is derived to examine the impact of non-normal underlying returns densities. Observed fat-tailed and skewed distributions are assumed to be the result of independent Gaussian processes with nonstationary parameters, modeled by discrete k-component independent normal mixtures. The mixture model provides an exact solution with intuitive appeal using weighted sums of Black-Scholes (B-S) solutions. Simulating returns densities representative of equity securities, significant mispricing by B-S is found in low-priced at- and out-of-the-money near-term options. The lower the variance and the higher the leptokurtosis and positive skewness of the underlying returns, the more pronounced is this mispricing. Values of in-the-money options and options with several weeks or more to expiration are closely approximated by B-S.
Static Noise Analysis for Digital Integrated Circuits in PartiallyDepleted SiliconOnInsulator TechnologyThis work was supported in part by the National Science Foundation under grant CCR9734216 and by a grant from the IBM Corporation.

In this paper, we extend transistor-level static noise analysis tools to consider the unique features of partially-depleted silicon-on-insulator (PD-SOI) technology: floating-body-induced threshold voltage variations and parasitic bipolar leakage currents. This involves a unique state-diagram abstraction of the device physics determining the body-potential of PD-SOI FETs. Based on this picture, a simple model of the body voltage is derived which takes into account modest knowledge of which nets have dependable, regular switching activity. Results are presented using a commericial static noise analysis tool incorporating these extensions.