cssi/SciSciGPT-SciSciNet huggingface dataset:
Biosensors for the detection of waterborne pathogens

Waterborne bacterial, viral and parasitic pathogens are a global health concern and their rapid and specific detection in contaminated potable water is of utmost importance. Biosensors using a variety of biorecognition molecules and transduction methodologies have been reported, and have the potential to enable highly sensitive detection of the analyte of interest in a short time with high specificity. However, there are several obstacles to the detection of waterborne pathogens—they tend to be present at very low concentrations in the environment and environmental samples contain numerous inhibitors of enzymatic reactions and interfering organisms and particulates. Here we present a review of the current state of biosensor technology with regard to the improvements needed over standard detection methods and the challenges presented by real environmental samples. Further, we identify future areas of focus necessary to realize novel detection devices capable of supplanting the gold standards of today.
Treatment of SSRI-Resistant Depression: A Meta-Analysis Comparing Within- Versus Across-Class Switches

Background Two broad treatment options exist for switching antidepressants for depressed patients who fail to respond to a selective serotonin reuptake inhibitor (SSRI): either a second course of SSRI therapy or a different class of antidepressants. The goal of the present work was to conduct a meta-analysis of studies comparing these two switch strategies. Methods Several sources were searched for randomized clinical trials comparing these two switch strategies. Results Data from four clinical trials ( n = 1496) were combined using a random-effects model. Patients randomized to switch to a non-SSRI antidepressant (bupropion, mirtazapine, venlafaxine) were more likely to experience remission than patients switched to a second SSRI (risk ratio=1.29, p = .007). Pooled remission rates were 28% (for non-SSRIs) and 23.5% (for SSRIs). There was also a nonsignificant trend ( p = .1) in the rate of discontinuation due to intolerance favoring the within-class switch strategy (risk ratio=1.23). There was no difference in response rates between the two treatment groups. Conclusions These results suggest a modest yet statistically significant advantage in remission rates when switching patients with SSRI-resistant depression to a non-SSRI rather than an SSRI antidepressant. With the number needed to treat (NNT) statistic as one indicator of clinical significance, nearly 22 SSRI nonresponders would need to be switched to a non-SSRI rather than a second SSRI antidepressant to obtain one additional remitter. This difference falls well below the mark of NNT=10 suggested by the United Kingdom's National Institute of Clinical Excellence but nonetheless might be of public health relevance given the large number of SSRI-resistant patients switched to an SSRI versus a non-SSRI antidepressant.
Long-term effects of 56Fe irradiation on spatial memory of mice: Role of sex and apolipoprotein e isoform

Purpose To assess whether the effects of cranial 56 Fe irradiation on the spatial memory of mice in the water maze are sex and apolipoprotein E (apoE) isoform dependent and whether radiation-induced changes in spatial memory are associated with changes in the dendritic marker microtubule-associated protein 2 (MAP-2) and the presynaptic marker synaptophysin. Methods and Materials Two-month-old male and female mice expressing human apoE3 or apoE4 received either a 3-Gy dose of cranial 56 Fe irradiation (600 MeV/amu) or sham irradiation. Mice were tested in a water maze task 13 months later to assess effects of irradiation on spatial memory retention. After behavioral testing, the brain tissues of these mice were analyzed for synaptophysin and MAP-2 immunoreactivity. Results After irradiation, spatial memory retention of apoE3 female, but not male, mice was impaired. A general genotype deficit in spatial memory was observed in sham-irradiated apoE4 mice. Strikingly, irradiation prevented this genotype deficit in apoE4 male mice. A similar but nonsignificant trend was observed in apoE4 female mice. Although there was no change in MAP-2 immunoreactivity after irradiation, synaptophysin immunoreactivity was increased in irradiated female mice, independent of genotype. Conclusions The effects of 56 Fe irradiation on the spatial memory retention of mice are critically influenced by sex, and the direction of these effects is influenced by apoE isoform. Although in female mice synaptophysin immunoreactivity provides a sensitive marker for effects of irradiation, it cannot explain the apoE genotype-dependent effects of irradiation on the spatial memory retention of the mice.
Regulation of phosphoenolpyruvate carboxylase from Crassula by interconversion of oligomeric forms.

Abstract Using size-exclusion high-performance liquid chromatography, it is shown that phosphoenolpyruvate carboxylase from Crassula argentea, a crassulacean acid metabolism (CAM) plant, exists primarily in the form of a tetramer of a 100-kDa subunit at night and as a dimer of the same subunit during the day. The tetrameric enzyme from night leaves is not inhibited by malate, while the dimeric form from day leaves can be completely inhibited by malate. The purified day, or dimer, form of the enzyme can be converted to the tetramer by concentration and exposure to Mg2+. When thus converted, the tetramer is insensitive to malate inhibition, and is more strongly activated by glucose 6-phosphate than the dimer. The purified night, or tetramer, form is converted to the dimer by incubation for 60 min at pH 8.2. This enzyme may also be converted to the dimer by adding 1.5 m m malate to the elution buffer, but preincubation for 15 min with phosphoenolpyruvate prevents disaggregation when chromatographed with buffer containing malate. Preincubation with 1 m m EDTA and subsequent chromatography with buffer containing malate shows a progressive dissociation of the tetrameric form with increasing time of preincubation. The implications of these observations for the diurnal regulation of phosphoenolpyruvate carboxylase in CAM metabolism are discussed.
Situational Analysis as an Avenue for Critical Qualitative Research Mapping Post-Katrina New Orleans

Hypercapitalism in the United States and globally has created neoliberal conditions that have reinterpreted notions of the public good as an entrepreneurial endeavor. In this current context, criti...
Biliary excretion of 2,4,5-trichlorophenoxyacetic acid in the rat.

Abstract Urethane-anesthetized, male Sprague-Dawley rats were administered 25 mg/kg 2,4,5-trichloropheno-xyacetic acid (2,4,5-T) intravenously. 6 h after administration, 15.7% of the dose was recovered in the bile. Reversed-phase high-performance liquid chromatography (HPLC) analysis of bile indicated that more than 85% of compound excreted in bile was unchanged 2,4,5-T. Since renal function was apparently compromised by the urethane anesthesia, only 4% of the dose was recovered in urine in 6 h. These data demonstrate that biliary excretion can be a slow but significant route of elimination under conditions of impaired renal function. Since 2,4,5-T is eliminated largely as the unchanged acid, reabsorption and thus enterohepatic circulation may significantly prolong the half-life of 2,4,5-T in the body.
RHEOLOGICAL AND MORPHOLOGICAL CHARACTERIZATION OF SELECTED POLY(ORGANO)PHOSPHAZENES

Rheological properties of selected poly(organo)phosphazenes have been studied using capillary rheometry. Melt viscosities of polymers were calculated as a function of shear stress and shear rate. Thermal stability was also studied. In the range of shear rate studied, all polyphosphazenes showed shear thinning behavior. The power law model was fitted to the data to get the power law index and the consistency index. Poly[bis(phenoxy)phosphazene] showed a Newtonian plateau at low shear rates whereas poly[bis(trifluoroethoxy)phosphazene] and poly[bis(p-phenylphenoxy)phosphazene] which exhibited liquid crystalline character were shear thinning even at low shear rates. Solid state capillary extrusion of polyphosphazenes was found to be more successful in fiber formation than other “state-of-the-art” processes, such as gel-spinning. The molecular weights of all polyphosphazenes synthesized were found to be too low for, Couette fiber spinning. Chemical, physical, and morphological studies were made on all fibers prepared. Many investigative techniques, such as X-ray diffraction, differential scanning calorimetry (DSC), density measurements, scanning electron microscopy (SEM), optical microscopy, solution nuclear magnetic resonance (NMR) spectroscopy, and gel permeation chromatography (GPC) analysis are featured in this paper as characterization tools.
Quantifying hillslope erosion rates and processes for a coastal California landscape over varying timescales

The Earth's surface erodes by processes that occur over different spatial and temporal scales. Both continuous, low-magnitude processes as well as infrequent, high-magnitude events drive erosion of hilly soil-mantled landscapes. To determine the potential variability of erosion rates we applied three independent, field-based methods to a well-studied catchment in the Marin Headlands of northern California. We present short-term, basin-wide erosion rates determined by measuring pond sediment volume (40 years) and measured activities of the fallout nuclides 137Cs and 210Pb (40–50 years) for comparison with long-term (>10 ka) rates previously determined from in situ-produced cosmogenic 10Be and 26Al analyses. In addition to determining basin-averaged rates, 137Cs and 210Pb enable us to calculate point-specific erosion rates and use these rates to infer dominant erosion processes across the landscape. When examined in the context of established geomorphic transport laws, the correlations between point rates of soil loss from 137Cs and 210Pb inventories and landscape morphometry (i.e. topographic curvature and upslope drainage area) demonstrate that slope-driven processes dominate on convex areas while overland flow processes dominate in concave hollows and channels. We show a good agreement in erosion rates determined by three independent methods: equivalent denudation rates of 143 ± 41 m Ma−1 from pond sediment volume, 136 ± 36 m Ma−1 from the combination of 137Cs and 210Pb, and 102 ± 25 m Ma−1 from 10Be and 26Al. Such agreement suggests that erosion of this landscape is not dominated by extreme events; rather, the rates and processes observed today are indicative of those operating for at least the past 10 000 years. Copyright © 2006 John Wiley & Sons, Ltd.
Prospective Phase I Study of Capecitabine and Oxaliplatin Concurrent with Radiation Therapy for the Treatment of Locally Advanced Pancreatic Adenocarcinoma, and Retrospective Comparison to Concurrent 5-Fluorouracil/Radiation and Gemcitabine/Radiation

Purpose The aims of this study is to determine the maximum tolerated dose of capecitabine and oxaliplatin (CAPOX) delivered concurrent with radiation therapy (RT) in the treatment of locally advanced pancreatic adenocarcinoma and to retrospectively compare outcomes with this regimen to concurrent 5-fluorouracil or capecitabine with RT (5FU-RT) or concurrent gemcitabine-based chemotherapy with RT (GEM-RT).
Caging the Beast: TRIM5α Binding to the HIV-1 Core

The potent HIV-1 inhibitor TRIM5α blocks HIV-1 infection by accelerating the uncoating of HIV-1. TRIM5α is known to form higher-order self-association complexes that contribute to the avidity of TRIM5α for the HIV-1 capsid, and are essential to inhibit infection; these higher-order self-association complexes are dependent upon an intact B-box 2 domain. Even though the ability to form higher-order self-association complexes resembles the clathrin triskelion that forms a protein array, or cage, around the endocytic vesicle, evidence for the ability of TRIM5α to assemble a similar type of structure surrounding the HIV-1 core has been lacking. Recent work by Ganser-Pornillos, Chandrasekaran and colleagues has now demonstrated the ability of the restriction factor TRIM5α to “cage” or “net” the HIV-1 core by forming an hexagonal array on the surface of the viral capsid [1]. This hexagonal array is strikingly similar in design to the array formed by the clathrin triskelion on the surface of the clathrin-coated endocytic vesicle. This remarkable finding represents an important advance on our understanding of the restriction factor TRIM5α, and suggests that TRIM5α cages the HIV-1 core in order to terminate infection. The present note discusses the implications of this discovery.
Interval estimation in a finite mixture model: Modeling P-values in multiple testing applications

The performance of interval estimates in a uniform-beta mixture model is evaluated using three computational strategies. Such a model has found use when modeling a distribution of P-values from multiple testing applications. The number of P-values and the closeness of a parameter to the boundary of its space both play a role in the precision of parameter estimates as does the ''nearness'' of the beta-distribution component to the uniform distribution. Three computational strategies are compared for computing interval estimates with each one having advantages and disadvantages for cases considered here.
Poster: Statistical Power and Energy Modeling of Multi-GPU Kernels

To improve the energy efficiency of parallel ap- plications on GPGPUs, a better understanding of the energy behavior of various applications is mandatory. In this study we employ statis- tical methods to model power and energy con- sumption of some common optimized high per- formance kernels (DGEMM, FFT, PRNG and FD stencils) on a multi-GPU platform.
Pharmacologic activation of the human coronary microcirculation in vitro: endothelium-dependent dilation and differential responses to acetylcholine

Objectives: In vivo studies of the human coronary resistance circulation cannot control for indirect effects of myocardial metabolism, compression, and neurohumoral influences. This study directly examined the vasodilator responses of the human coronary microcirculation to both receptor-dependent and -independent agonists. Methods: Atrial arterioles were dissected from human right atrial appendage (103±2 μm diameter, n =185 vessels from 145 patients) obtained at the time of cardiopulmonary bypass and left ventricular vessels from explanted human hearts (148±10 μm diameter, n =57 vessels from 18 patients). After dissection, vessels were mounted onto pipettes in Kreb's buffer under conditions of zero flow and at a constant distending pressure of 60 mmHg. Drugs were applied extraluminally and steady state changes in diameter measured with videomicroscopy. Results: After contraction by endothelin or spontaneous tone, increasing concentrations of adenosine diphosphate (ADP) produced a similar dose-dependent dilation in vessels from atria (maximum 89±4%, n =76) and ventricles (maximum 74±9%, n =10). The dilation to ADP was abolished by mechanical removal of the endothelium. Similar dilator responses were found to bradykinin, substance P, arachidonic acid, and the calcium ionophore A23187 in both atria and ventricle. In contrast, acetylcholine (ACh) constricted all atrial vessels (−58±3%, n =63) regardless of patient age or underlying disease. This constriction was attenuated by denudation, but not affected by inhibition of nitric oxide synthase or cyclo-oxygenase. Microvessels isolated from human ventricle exhibited a heterogeneous response to ACh with dilation being the predominant response. Conclusions: We conclude that isolated human coronary arterioles demonstrate endothelium-dependent dilation. However, the response to acetylcholine is unique with vasoconstriction in atrial vessels and dilation in ventricular arterioles.
UNIVERSALITY CLASSES FOR INTERFACE GROWTH WITH QUENCHED DISORDER

We present numerical evidence for the existence of two distinct universality classes characterizing driven interface roughening in the presence of quenched disorder. The evidence is based on the behavior of \ensuremath{\lambda}, the coefficient of the nonlinear term in the growth equation. Specifically, for three of the models studied, \ensuremath{\lambda}\ensuremath{\rightarrow}\ensuremath{\infty} at the depinning transition, while for the two other models, \ensuremath{\lambda}\ensuremath{\rightarrow}0.
Interaction of epsilon-globin cis-acting control elements with erythroid-specific regulatory macromolecules.

Abstract We have used a competition assay to investigate the influence of erythroid-specific cellular factors on transcription from the human epsilon-globin major cap site promoter and the minor promoter located 200 base pairs (bp) upstream from the epsilon-globin cap site. In the human erythroid cell line K562, competition of the epsilon-globin major cap site promoter linked to the chloramphenicol acetyltransferase (CAT) gene (epsilon P-CAT) with the same promoter fragment linked to a neomycin resistance gene (epsilon P-NEO) leads to a reduction in CAT activity. This indicates the specific presence of K562 cells of factor(s) which interact with the 200-bp promoter fragment (isolated from the gene body or flanking sequences) to activate transcription from the epsilon-globin major cap site. Competition of the epsilon-globin major promoter (as epsilon P-CAT) with the upstream minor epsilon-globin promoter (as epsilon P2-NEO) also leads to a reduction in CAT activity, indicating that both promoters share erythroid-specific trans-acting factors. The reverse competition (epsilon P2-CAT with epsilon P-NEO) leads to an increase in CAT activity, suggesting that the existence of erythroid-specific factor(s) which repress transcription from the 200-bp-upstream epsilon-globin promoter.
Race, academic achievement, and self-concept of ability

In the year-and-a-half since the College Board released detailed tables on SAT scores by race, much of the heated reaction has now abated. This study explores the data behind those tables and seeks a fuller explanation of the observed differences in SAT scores among racial and ethnic segments of college-bound test takers. It highlights a social psychological correlate that mediates between environmental factors and SAT performance, beginning with the finding that blacks at the same level of test performance exhibit greater self-esteem than whites on a series of self-rated abilities. Implications of the analysis are discussed and directions for further research suggested.
On ‘flip‐flopping’: Branded stance‐taking in U.S. electoral politics1

This article examines stance in U.S. political discourse, taking as its empirical point of departure Democratic candidate John Kerry's epistemic stance-taking in the televised 2004 presidential debates. Kerry's stance-taking is shown to help display the characterological attribute of ‘conviction’ and serve as a rejoinder to critics who had branded him as a ‘flip-flopper.’ His stance-taking is thus not primarily ‘to’ or ‘for’ copresent interactants, but is largely interdiscursive in character. ‘Conviction’ and its opposite, ‘flip-flopping,’ suggest further how stance-taking itself has been an object of typification in the agonistic dynamics of candidate branding and counter-branding. In moving from epistemic stance-taking in discourse to models of the stance-taker as a social type, this article addresses questions about the units and levels of analysis needed to study stance in contemporary political discourse.
Effects of agriculture on habitat complexity in a prairie-forest ecotone in the Southern Great Plains of North America.

Abstract Ecotones are transition zones that may be particularly sensitive to both natural and human-related disturbances to the environment. Agricultural development in the southern Great Plains of North America has resulted in marked changes in habitats and in the configurations of those habitats. Based on panchromatic National High Altitude Photography (NHAP), the effects of such development on spatial extent, relative abundance, and habitat-patch complexity for 15 land-cover types were evaluated by contrasting landscape-level habitat characteristics of a managed-native landscape (Fort Sill Military Reservation in southwestern Oklahoma, USA) with those of the adjacent landscape, where agricultural uses were the most prevalent. The managed-native landscape was predominately grassland (62.2%), with most being mixed grassland (43.4%), while the surrounding agriculture landscape was dominated by rangeland (50.7%) and cropland (13.6%). The mean area and perimeter of grassland patches in the managed-native area were greater than in the agriculture area, while values of these measures for cropland and rangeland patches were greater in the agriculture area. Mean patch shape (corrected perimeter/area) was highest for bottomland-forest, riparian, and cross-timbers habitats, reflecting the fact that these habitats typically are elongated in shape. Mean patch shapes of mesquite-savanna, bottomland-forest, and riparian patches were significantly lower in the agriculture area, a result primarily due to the straightening of edges of patches of these habitats when croplands were developed adjacent to them. With two relatively large reservoirs being present in the agriculture area, mean patch shape for water also was significantly lower than that in the managed-native landscape. Overall, fractal dimension—a measure of shape complexity of the perimeter of habitat patches—was significantly lower (based on Monte Carlo simulation) for the agriculture area than the managed-native area, mirroring the fact that habitat edges in the cropland-dominated area were less complex for many of the land-cover types. For specific land-cover types, cropland had a significantly higher fractal dimension in the agriculture area than the managed-native area, while the opposite was true for water, mixed grass, distributed areas, riparian, and bottomland forest. These results indicate that habitat complexity in the prairie-forest ecotone is reduced by agricultural development, which potentially could have deleterious effects on native plants and animals.
Everyday miracles: Using client narratives to write teaching vignettes for faith communities

In the past two decades, churches and faith-based organizations have played an increasing role in the provision of social services. Because teachings about poverty and how to treat people who are poor are prevalent in major religions of the world, faith communities seem to be a natural fit as service providers for families transitioning from welfare to work. However, it is conceivable that lay persons who volunteer in faith-based programs will face challenges when they begin to provide services to people who are poor. The purpose of this brief article is to present vignettes (based on Biblical poetry, psalms, proverbs, and parables) that are suitable for use in training volunteers from faith communities who will be working with families transitioning from welfare to work.
Prior inhibition of vasoconstrictors normalizes GFR in postobstructed kidneys.

Prior inhibition of vasoconstrictors normalizes GFR in postobstructed kidneys. The present studies were designed to analyze the potential contribution of angiotensin II and thromboxane A 2 to the remarkable decrease in glomerular filtration rate (GFR) and renal plasma flow observed after unilateral release of 24-hour bilateral ureteral obstruction. Pretreatment of the animals with inhibitors of either thromboxane or angiotensin synthesis for 48 hours prior to and during obstruction eliminated the contribution of these vasoconstrictors. Inhibition of these vasoconstrictors during the period of obstruction results in a greater increase in renal plasma flow and GFR than when inhibition was accomplished after release of the obstruction. These data suggest a greater role for these vasoconstrictors in the decrease in GFR that occurs with obstruction. Simultaneous inhibition of thromboxane and angiotensin production normalized GFR of the postobstructed kidney. Administration of atrial peptide after release of obstruction in the different groups of rats resulted in further increases in GFR, urine flow and absolute sodium excretion. It is suggested that atrial peptide participates in the renal hemodynamic changes that occur in the postobstructed kidney.
The Full-Spectrum Correlated-k Distribution for Thermal Radiation From Molecular Gas-Particulate Mixtures

A new Full-Spectrum Correlated-κ Distribution has been developed, which provides an efficient means for accurate radiative transfer calculations in absorbing/emitting molecular gases. The Full-Spectrum Correlated-κ Distribution can be used together with any desired solution method to solve the radiative transfer equation for a small number of spectral absorption coefficients, followed by numerical quadrature. It is shown that the Weighted-Sum-of-Gray-Gases model is effectively only a crude implementation of the Full-Spectrum Correlated-κ Distribution approach. Within the limits of the Full-Spectrum Correlated-κ Distribution model (i.e., an absorption coefficient obeying the so-called scaling approximation), the method is exact. This is demonstrated by comparison with line-by-line calculations for a one-dimensional CO 2 -N 2 gas mixture as well as a two-dimensional CO 2 -H 2 O-N 2 gas mixture with varying temperature and mole fraction fields
Barium Azacryptand Sodide, the First Alkalide with an Alkaline Earth Cation, Also Contains a Novel Dimer, (Na2)2-

The first barium sodide, with stoichiometry Ba2+(H5Azacryptand[2.2.2]-)Na-·2MeNH2, was synthesized by the reaction of Ba, Na, and H6Azacryptand[2.2.2] in NH3−MeNH2 solution. It was characterized by X-ray crystallography, 23Na MAS NMR, hydrogen evolution, DSC, optical spectroscopy, and magnetic susceptibility. This is the first sodide in which the sodium anions form (Na2)2- dimers. Previous theoretical predictions were verified by a calculation of the potential energy curve for the dimer in the field of the surrounding charges, whose positions were determined from the crystal structure.
Mechanical Properties of ZK60 Magnesium Alloy Processed by High-Pressure Torsion

Severe plastic deformation routes such as high-pressure torsion (HPT) are capable of producing ultrafine grain sizes in various alloys, specifically in magnesium alloys which exhibit poor ductility due to their hexagonal close-packed (hcp) crystal structure. HPT was performed on ZK60 magnesium alloy samples at room temperature under a pressure of 2.0 GPa up to 5 turns. The Vickers microhardness values were obtained from the centre to the edge of the disc samples and they show a slight hardness gradient with values which are lower at the centre of the samples and higher towards the edge. By increasing the numbers of turns in HPT, the hardness values increase to a saturation level and the gradient is removed. Tensile tests were performed at high temperatures and the results reveal a significant increase in elongation to failure as the numbers of turns in HPT increases. It is shown that microstructural analysis is in agreement with the results obtained from mechanical testing.
Killing of Escherichia coli by β-lactams at different inocula

Escherichia coli is a common pathogen implicated in intra-abdominal infections; a heavy bacterial burden is often encountered, and the clinical utility of beta-lactams may be limited by the inoculum effect. We examined the impact of a high inoculum on the bactericidal activity of various beta-lactams against E. coli. Two wild-type, an extended-spectrum beta-lactamase-producing, and a plasmid-mediated AmpC-producing strains, were used. Clinically achievable concentrations of piperacillin/tazobactam, ceftriaxone, and ertapenem were investigated. Viable bacterial burden was serially determined for 24 h by quantitative culture. All 3 beta-lactams demonstrated significant killing against the standard inoculum (10(5) CFU/mL) of susceptible strains. However, the activity of piperacillin/tazobactam was drastically reduced with 10(8) CFU/mL of bacteria. Ertapenem was the least affected by the inoculum effect in all strains. Our results suggest that different beta-lactam subclasses have a distinct killing profile against a dense E. coli population. Comparative in vivo/clinical investigations are warranted to validate our findings.
The Possibility of TEM-based X-ray Microanalysis with a Microcalorimeter Detector

Extended abstract of a paper presented at the Pre-Meeting Congress: Materials Research in an Aberration-Free Environment, at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, July 31 and August 1, 2004.
NAVIGATION IN THE MORRIS SWIM TASK AS A BASELINE FOR DRUG DISCRIMINATION: A DEMONSTRATION WITH MORPHINE

A morphine versus saline discrimination was demonstrated using the Morris swim task as the behavioral baseline. The apparatus was a large circular pool filled with water made opaque by floating polypropylene pellets. Rats were placed in the tank in randomly selected locations (12 trials per session) and could escape by swimming to a platform submerged 2 cm below the surface. Morphine (5.6 mg/kg) or saline was injected prior to training sessions. The position of the platform in a given session depended on the drug condition, thus forming the basis for discriminative responding. Three of the 4 rats acquired the discrimination, as evidenced by direct swims to the condition-appropriate platform. Generalization probe sessions were conducted following acquisition. Probe sessions were preceded by injections of morphine (0, 1.0, 3.0, 5.6, or 10.0 mg/kg) and involved placing the rat in the pool for 1 min without a platform. Swim patterns revealed a gradient, with probe swimming more concentrated in the area of the morphine platform position after higher morphine doses. In addition, dose-dependent increases in the likelihood of swimming first to the morphine-associated platform location were obtained. These results illustrate the generality of drug discrimination across different behavioral procedures, and of particular interest with respect to spatial learning, demonstrate interoceptive stimulus control of navigation.
Binary pseudo-random gratings and arrays for calibration of the modulation transfer function of surface profilometers: recent developments

The major problem of measurement of a power spectral density (PSD) distribution of the surface heights with surface profilometers arises due to the unknown Modulation Transfer Function (MTF) of the instruments. The MTF tends to distort the PSD at higher spatial frequencies. It has been suggested [Proc. SPIE 7077-7, (2007), Opt. Eng. 47 (7), 073602-1-5 (2008)] that the instrumental MTF of a surface profiler can be precisely measured using standard test surfaces based on binary pseudo-random (BPR) patterns. In the cited work, a one dimensional (1D) realization of the suggested method based on use of BPR gratings has been demonstrated. Here, we present recent achievements made in fabricating and using two-dimensional (2D) BPR arrays that allow for a direct 2D calibration of the instrumental MTF. The 2D BPRAs were used as standard test surfaces for 2D MTF calibration of the MicromapTM-570 interferometric microscope with all available objectives. The effects of fabrication imperfections on the efficiency of calibration are also discussed.
Survivability of optical fibers in space

The survivability of optical fibers for data bus and gyroscope applications in the natural space radiation environment has been analyzed using radiation-induced loss data of single mode, multimode, and polarization-maintaining fibers. Since it is virtually impossible to simulate the dynamic conditions of space, extrapolations have been made from measurements at dose rates, temperatures, and total doses different from those onboard spacecraft. The anticipated degradation of most Ge-doped silica core fibers and all pure silica core fibers appears to be well within allowable margins in fibers for data bus applications, while the radiation sensitivity of polarization-maintaining fibers could result in a significant decrease in fiber gyro performance.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Protective effects of zinc salts on TPA-induced hepatic and brain lipid peroxidation, glutathione depletion, DNA damage and peritoneal macrophage activation in mice.

Abstract 1. 1. The comparative protective abilities of zinc l -methionine, zinc dl -methionine, zinc sulfate, zinc gluconate, l -methionine, dl -methionine, and vitamin E succinate (VES) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced lipid peroxidation, DNA fragmentation, and glutathione depletion in the hepatic and brain tissues, and production of reactive oxygen species by peritoneal macrophages were assessed. In addition, mice were fed a zinc-deficient diet for 5 weeks, and treated with TPA and/or zinc l -methionine or zinc dl -methionine, and similar studies were conducted. 2. 2. The zinc-deficient diet induced oxidative stress in the hepatic and brain tissues as well as in the peritoneal macrophages as evidenced by significantly enhanced lipid peroxidation, DNA fragmentation, glutathione depletion, and production of reactive oxygen species. 3. 3. Treatment of mice with zinc l -methionine, zinc dl -methionine, and VES decreased TPA-induced reactive oxygen species production as evidenced by significant decreases in chemiluminescence in peritoneal macrophages by approximately 45%, 31%, and 47%, respectively, and cytochrome c reduction by approximately 54%, 35%, and 41%, respectively, as compared with control values. Similar results were observed with liver and brain lipid peroxidation, DNA fragmentation, and glutathione depletion. 4. 4. Zinc salts and antioxidants provided significant protection against TPA-induced oxidative damage. Zinc dl -methionine provided the best protection.
[8,8-η2-{η2-(BH3)Ph2PCH2PPh2}-nido-8,7-RhSB9H10]: A Rhodathiaborane with a Novel Bidentate Chelating Ligand

A unique bidentate phosphane/borane ligand is present in 2, which is formed by treatment of the rhodathiaborane 1 with BH3⋅THF [Eq. (1)]. Compound 1 was prepared by the reaction of the unsaturated cluster [8,8-(PPh3)2-nido-8,7-RhSB9H10] with bis(diphenylphosphanyl)methane (dppm). The dppm–BH3 ligand in 2 coordinates to the Rh center through a P atom and a BH3 moiety, the latter by two bridging B-H-Rh bonds.
Modeling of Solidification and Filling of Thin-Section Castings

A finite element model for simulating dendritic solidification of multicomponent-alloy castings is used to study the filling and solidification of castings of thin cross section. The model solves the conservation equations of mass, momentum, energy, and alloy components and couples the solution with the thermodynamic of the multicomponent alloy through a phase diagram equation. The transport of mass and energy in the mushy zone is done considering the mushy zone as a porous medium of variable porosity. The same set of conservations equations are used for the liquid, solid and mushy zones, in which the volume fraction of liquid acts as the variable that makes the equations transition continuously from one zone to another (Felicelli et al. [1]). During filling, the model tracks the advancing front as the metal flows into the thin mold, and solidification is calculated as the metal loses energy by convection and radiation to the mold, including the dynamic calculation of view factors. The code supports two fluid models that emulate the flow behavior under equiaxed or columnar solidification. In the former case a slurry fluid model is used in which the viscosity is determined by the volume fraction of solid. In this slurry state, the solid and liquid move at the same velocity. For the case of columnar solidification, the solid is fixed and the liquid flows through a porous structure of dendrictic solid. The model development is based on the work by Felicelli et al. [2], to which several features were added, including a front-tracking technique (Gao [3]) and thermal radiation boundary conditions. Calculations for Ni and Al alloys were performed to illustrate the effect of several physical and operation parameters in the filling of a horizontal channel of thin thickness. A wide range of process parameters was tested in order to determine how much of the channel length could be filled before blockage of flow by solidification occurred. In a separate section, the effect of alloy concentration on the fluidity was studied using a Pb-Sn hypoeutectic system, and the importance that the dendrite breaking phenomenon can have on the results is shown. Conclusions about the parameters that most influence the filling process are presented, as well as recommendations on which experimental data are more critical in order to conduct a proper validation of this type of models.Copyright © 2005 by ASME
A New Analysis of Slater's Compressibility Data

The variation of interatomic forces with interatomic distances in crystals may be determined empirically from compressibility data. The experimentally possible range of variation in interatomic distance is, however, so small that the form of the force function valid for extrapolation to much greater distances cannot be adequately determined. From an analysis of Slater's compressibility data for the alkali halides it appears that for them the interionic forces of repulsion may be derived from a common force function. Because of the relatively large variation of lattice constant between the different alkali halides it is possible to determine a form for this common force function which is valid for relatively large variations in interatomic separation. The force function so found differs but little from the inverse power or from the exponential forms for small displacements from the equilibrium position. It drops off more rapidly, however, for increasing distances and increases more rapidly for decreasing distances. The solution given has the interesting property that of all possible force functions compatible with Slater's compressibility data it is the least favorable for the formation of a secondary structure.
Mini workshop — Great problems lead to great projects: A first year seminar course

In 2007 WPI initiated the Great Problems Seminars to engage First Year students with current events, societal problems and human needs while developing skills that will facilitate subsequent project work. These seminars focus on large global issues — energy and its utilization, food and hunger, disease and healthcare delivery and the NAE Grand Challenges. Each is led by two faculty from disparate departments who expose the students to the complexity of the problem using a number of disciplinary perspectives. Students develop information literacy, effective writing and speaking skills, while working in teams on short assignments. For the final project student teams work with faculty supervision to analyze some aspect of the problem and/or develop a partial solution. The seminars culminate in a Project presentation day where all student groups present a poster on their work. We have assessment data that show that the courses achieve their desired outcomes. The special session will review the motivation to create these courses and provide information about course organization and logistics. Participants will review student projects, discuss the preparation required, and determine how elements of this program can be utilized on their home campus. Ideas generated by participants will be shared with all.
Optimal resource assignment of preemptive periodic tasks on multiple processors

In this article we examine the problem of preemptively scheduling periodically occurring tasks on a system of parallel processors so as to maximize a linear function of the tasks completed. We show that polynomial time solutions exist for all the no-deadline problems, derive an O(n log n) algorithm for the preemptive parallel processor problem, and include results for minimization of number of processors and maximization of flexibility for handling additional tasks. We present lower and upper bounds on the number of preemptions. We show that all optimization problems with either arbitrary or next-request deadlines are NP-hard.
Nonideal isentropic gas flow through converging-diverging nozzles

A method for treating nonideal gas flows through converging-diverging nozzles is described. The method incorporates the Redlich-Kwong equation of state. The Runge-Kutta method is used to obtain a solution. Numerical results were obtained for methane gas. Typical plots of pressure, temperature, and area ratios as functions of Mach number are given. From the plots, it can be seen that there exists a range of reservoir conditions that require the gas to be treated as nonideal if an accurate solution is to be obtained.
Hemodialysis urea rebound: The effect of increasing dialysis efficiency

Urea rebound has been documented to occur after hemodialysis, but the magnitude and causes are not clearly defined. In this study we evaluated the effect of high-flux hemodialysis on urea rebound and Kt/V. Blood urea nitrogen samples were obtained before, immediately after, and 30 minutes after hemodialysis in 49 patients. Rebound was evaluated with respect to dialysis efficiency, dialysis treatment time, the occurrence of hypotension, and hematocrit. Urea rebound was significant and resulted in an overall decrease in Kt/V from 1.2 +/- 0.3 to 1.0 +/- 0.2 (P < 0.001). Of the 45 patients with a measured Kt/V of greater than 1.0, 40% had an actual delivered Kt/V of less than 1.0 once rebound was taken into account. Urea rebound correlated strongly with dialysis efficiency but not with hypotension, suggesting that rebound resulted primarily from delayed urea mass transfer across cell membranes. We conclude that increasing dialysis efficiency increases urea rebound and increases the error in Kt/V determinations from single pool urea kinetics.
Debating Arabic on Al-Jazeera: Endangerment and Identity in Divergent Discourses

Eight debates on Al-Jazeera specifically, on the Arabic language, highlight the divergent and convergent discourses about the status of the language and its use today in the Arab world. All address the issue of the weakness of the Arabic language, both internally between formal and dialect, and externally in the face of globalizing English. The participants also link the Arabic language to issues of identity and who the Arabs ‘are’ during this era of globalization. The article outlines the intellectual roots that many of the participants draw upon—that of the Arab nahda of the late nineteenth and early twentieth centuries. Finally, the article points out that there is a divergence between the general direction of scholarship produced in the West on the Arabic language and about the Al-Jazeera network and the broader intersection of language and nationalism addressed by the Al-Jazeera participants. Beyond noting the obvious linkage between language and nationalism, how actual participants deal with their intellectual legacies while attempting to prescribe and influence the present deserves greater analysis in the case of the Arabic language and its most noted vehicle today—the Al-Jazeera satellite television network.
A perturbative approach to the pomeron (II). A simple model

Abstract The perturbative approach to the pomeron via the multi-fireball expansion proposed in the preceding paper is further analyzed in the context of a simplified model. A detailed picture of the pomeron is given, with special attention paid to the extent of factorization and the strength of the output two-pomeron cut. The role of various production mechanisms in building the output singularities is clearly exhibited. The energy dependence of total cross sections is discussed in the framework of the perturbative series and compared to the complementary interpretation in terms of output Regge poles. The possibility of a rising total cross section is carefully examined.
A rearrangement based proof for the existence of extremal functions for the Sobolev–Poincaré inequality on Bn

Abstract Existence of extremals for 1 p ⩽ n + 1 2 is shown for the Sobolev–Poincare inequality on B n using a mean-value zero preserving rearrangement.
Functional and catastrophic thermal failures in bipolar electronic circuits

In semiconductor devices interactions between electrical and thermal effects result from the selfheating phenomenon. Due to selfheating and non-ideal heat transfer from a device to surroundings, the junction (inside) temperature rise above the ambient temperature is observed, and as a result the form of the d.c. characteristics of devices can be essentially changed. This temperature rise can lead to functional failure of the circuit in which the device is used, or to catastrophic failure of the device. In the paper some examples of such circuits as the transistor switch and the differential pair are described.
The Relation Between Electron Field Emission and Contact Electromotive Force for Liquid Mercury

The relation between contact e.m.f. and the impulsive potential necessary to initiate a vacuum spark has been studied for a liquid mercury cathode. The magnitude and time of application of the impulsive potential were determined by a cathode-ray oscillograph so that possible distortion of the mercury surface produced by the electric field could be evaluated. For impure mercury no definite relation could be found. However, for carefully distilled mercury the relation between the work function and breakdown field was in qualitative but not in quantitative agreement with theory.
Integrated circuit microsensor for selectively detecting nitrogen dioxide and diisopropyl methylphosphonate

A novel gas-sensitive microsensor, known as the interdiginatated gate electrode field effect transistor (IGEFET), was realized by selectively decositing a chemically-active, electron-beam evaporated copper phthalocyanine (CuPc) thin film onto an integrated circuit (IC). When isothermally operated at 150 °C, the microsensor can selectively and reversibly detect parts-per-billion concentration levels of nitrogen dioxide (NO2) and diisopropyl methylphosphonate (DIMP). The selectivity feature of the microsensor was established by operating it with a 5 V peak amplitude, 2 μs duration, 1000 Hz repetition frequency pulse, and then analyzing its time- and frequency-domain responses. The envelopes associated with the normalized-difference Fourier transform magnitude spectra, and their derivatives, reveal features which unambiguously distinguish the NO2 and DIMP challenge gas responses. Furthermore, the area beneath each response envelope may correspondingly be interpreted as the microsensor's sensitivity for a specific challenge gas concentration. Scanning electron microscopy (SEM) was used to characterize the morphology of the CuPc thin film. Additionally, infrared (IR) spectroscopy was employed to verify the α- and β-phases of the sublimed CuPc thin films and to study the NO2- and DIMP-CuPc interactions.
Power and thermal constrained test scheduling

We propose a test scheduling algorithm that ensures the resource compatibility and satisfies both power and thermal constraints. The proposed algorithm can start a test at an arbitrary time and it has the capability of delaying a test to let a core cool down to find a valid schedule even when traditional scheduling schemes cannot find a solution. To reduce the execution time of thermal simulation, we exploit superposition principle to compute the thermal profile rapidly and accurately. We apply our scheduling algorithm to ITC'02 SoC benchmarks and the results show a remarkable improvement in the total test length over other methods, while meeting the thermal and power constraints.