cssi/SciSciGPT-SciSciNet huggingface dataset:
Optical absorption, 31P NMR, and photoluminescence spectroscopy study of copper and tin co-doped barium-phosphate glasses

Abstract The optical and structural properties of 50P 2 O 5 :50BaO glasses prepared by melting have been investigated for additive concentrations of 10 and 1 mol% of CuO and SnO dopants. Absorption and photoluminescence spectroscopies were employed in the optical characterization, whereas structural properties were assessed by 31 P nuclear magnetic resonance (NMR) spectroscopy. Residual Cu 2+ was detectable by absorption spectroscopy for the highest concentration of CuO and SnO. More prominently, the optical data suggests contributions from both twofold-coordinated Sn centers and Cu + ions to light absorption and emission in the glasses. The luminescence depends strongly on excitation wavelength for the highest concentration of dopants where a blue–white emission is observed under short-wavelength excitation (e.g., 260 nm) largely due to tin, while an orange luminescence is exhibited for longer excitation wavelengths (e.g., 360 nm) essentially due to Cu + ions. On the other hand, dissimilar luminescent properties were observed in connection to Cu + ions for the lowest concentration studied, as the copper ions were preferentially excited in a narrower range at shorter wavelengths near tin centers absorption. The structural analyses revealed the glass matrix to be composed essentially of Q 2 (two bridging oxygens) and Q 1 (one bridging oxygen) phosphate tetrahedra. A slight increase in the Q 1 / Q 2 ratio reflected upon SnO doping alone suggests a major incorporation of tin into the glass network via P–O–Sn bonds, compatible with the 2-coordinated state attributed to the luminescent Sn centers. However, a significant increase in the Q 1 / Q 2 ratio was indicated with the incorporation of copper at the highest concentration, consistent with a key role of the metal ions as network modifiers. Thus, the change in Cu + optical properties concurs with different distributions of local environments around the ions induced by variation in metal ion concentration. Luminescence decay curve analyses were found in agreement with the presence of Cu + ions in the glasses suggesting their existence in tetragonally-distorted octahedral sites.
Effect of correlations and disorder on electron states in the Mott-Hubbard insulator V2O3.

We compare vanadium-deficient (nonstoichiometric) and titanium-doped vanadium sesquioxide through measurements of the electrical resistivity at a series of hydrostatic pressures, the magnetic susceptibility, and the low-temperature specific heat: all as a function of T. The pressure dependence of the critical temperature for the discontinuous metal-antiferromagnetic-insulator transition as well as the temperature dependence of the magnetic susceptibility track in the two cases. However, the pressure dependence of the Hubbard gap, the slower than exponential form of the low-temperature resistivity, and the concentration of two-level systems are markedly different for ${\mathrm{V}}_{1.9967}$${\mathrm{O}}_{3}$ and (${\mathrm{V}}_{0.99}$${\mathrm{Ti}}_{0.01}$${)}_{2}$${\mathrm{O}}_{3}$. We discuss our results in terms of the intra-atomic Coulomb repulsion, which is of comparable magnitude to the bare bandwidth of the vanadium 3d states. The band splitting in the antiferromagnetic insulating state is argued to cross over to a Slater-type splitting between the subbands narrowed by correlations with a sufficient degree of oxygen nonstoichiometry or Ti doping.
How SOX affects executive compensation

Compensation committees are facing challenging new governance requirements under the Sarbanes-Oxley Act (SOX). The author warns that companies must rethink how they handle and reduce risk—including better governance for compensation committees. What's more, any changes must be more than mere window dressing. But internal auditors can help. © 2004 Wiley Periodicals, Inc.
Direct enzymatic assay for reduced and oxidized glutathione

A modification of a specific assay for the reduced (GSH) and oxidized (GSSG) species of glutathione is presented and compared with the method of Ellman (1959). The present method has an enzymatic basis using GSH as the specific cosubstrate for glutathione S-transferase activity. The enzymatic method resulted in comparable, but consistently lower, values for GSH and GSSG than did the method of Ellman. The greatest differences between the two methods occurred when measuring renal GSH and GSSG, possibly due to the presence of mixed thiols in the kidney. This enzymatic method was more specific and provided an accurate and reproducible method of GSH and GSSG determination.
Validation of an assay for the determination of cotinine and 3-hydroxycotinine in human saliva using automated solid-phase extraction and liquid chromatography with tandem mass spectrometric detection

The validation of a high-performance liquid chromatographic method for the simultaneous determination of low level cotinine and 3-hydroxycotinine in human saliva is reported. Analytes and deuterated internal standards were extracted from saliva samples using automated solid-phase extraction, the columns containing a hyper cross-linked styrene–divinylbenzene copolymer sorbent, and analysed by reversed-phase liquid chromatography with tandem mass spectrometric detection (LC–MS–MS). Lower limits of quantitation of 0.05 and 0.10 ng/ml for cotinine and 3-hydroxycotinine, respectively, were achieved. Intra- and inter-batch precision and accuracy values fell within ±17% for all quality control samples, with the exception of quality control samples prepared at 0.30 ng/ml for 3-hydroxycotinine (inter-day precision 21.1%). Results from the analysis of saliva samples using this assay were consistent with subjects’ self-reported environmental tobacco smoke (ETS) exposures, enhancing the applicability of cotinine as a biomarker for the assessment of low level ETS exposure.
Postprocedural Management of Patients Undergoing Endovascular Therapy for Acute and Chronic Lower-Extremity Deep Venous Disease

Endovascular therapy for acute and chronic lower-extremity deep venous disease seeks to improve patency and flow to ameliorate severe symptoms, prevent the postthrombotic syndrome, and treat existing chronic venous disease. Close postprocedure monitoring in the weeks to months following the intervention with implementation of an anticoagulation and symptom management strategy maximizes the likelihood of a durable result. This article outlines several such strategies based on the presenting pathology, results of the intervention, and biological characteristics of the patient.
Management intensification effects on autotrophic and heterotrophic soil respiration in subtropical grasslands

Sustainable management of grassland ecosystems for improved productivity can enhance their potential to sequester atmospheric CO2 in the soil. However, land-use management influences the quantity and quality of carbon (C) inputs which may, in turn, affect microbial activity and soil C decomposition rates. Understanding the potential changes in magnitude of soil C loss through respiration is critical for a comprehensive assessment of land-use conversion and grassland management impacts on terrestrial C dynamics. Thus, this study was designed to assess the effect of land-use management intensification on soil respiration in subtropical grasslands. Experimental sites consisted of a gradient of management intensities ranging from native rangeland (lowest), silvopasture (intermediate), to sown pasture (highest). Increasing management intensity from native rangeland to sown pasture elevated soil respiration. There was a significant effect of ‘season vs. management’ interaction on total soil respiration (RS), with greater increases in RS from summer to winter in sown pasture (∼200%) compared to native rangeland and silvopasture (∼91%). The temperature sensitivity of RS and heterotrophic soil respiration (RH) increased with management intensification, with a highest Q10 of 1.55 and 2.29, in sown pasture, compared to Q10 values of 1.09 and 1.48 in native rangelands. These results suggested that potential increases in soil C stock with intensification may be susceptible to faster turnover under warming climate scenarios. Improved resilience (and longer residence) of additionally sequestered soil C after intensification may be crucial for long-term ecological resilience, especially with changing climatic conditions. These findings are relevant for sustainable grassland management, especially within subtropical ecoregions, and add to the understanding of changes that may occur in rates of soil C losses as native grasslands are converted to more productive grassland ecosystems.
Primary tacrolimus (FK506) therapy and the long-term risk of post-transplant lymphoproliferative disease in pediatric liver transplant recipients

While the overall incidence of post-transplant lymphoproliferative disease (PTLD) in pediatric liver transplant recipients has been reported to be 4-11%, the long-term risk of PTLD associated with primary tacrolimus therapy is unknown. Therefore, in order to determine the incidence and long-term risk of PTLD, the present study examined 131 pediatric recipients who underwent liver transplantation (LTx) between October 1989 and December 1991 and received primary tacrolimus therapy. This cohort of children was evaluated over an extended time-period (until December 31 1996) with a mean follow-up of 6.3 yr. Actuarial Kaplan-Meier analysis was utilized to determine the risk of PTLD over time. The overall incidence of PTLD was 13% (17/131) with an average age of 4.3 +/- 0.75 yr at diagnosis. Pretransplant Epstein-Barr virus (EBV) serologies were negative in 82%, positive in 12%, and not available in 6% of the patients. The median time to diagnosis of PTLD post-Tx was 11.9 months (mean 16.4 +/- 3.9, range 1.7-63.0 months). Mean tacrolimus dose and plasma trough level (as evaluated by enzyme-linked immunosorbent assay [ELISA]) at the time of diagnosis was 0.32 +/- 0.06 mg/kg/day and 1.3 +/- 0.3 ng/mL, respectively. The cumulative long-term risk of PTLD was found to increase over time: 3% at 6 months, 8% at 1 yr, 12% at 2 yr, 14% at 3 yr, and 15% at 4 and 5 yr. Mortality from PTLD was 12% (two of 17 patients). Primary tacrolimus use in pediatric LTx has a long-term risk of PTLD approaching 15%, with the majority of episodes (78%) occurring in the first 2 yr, suggesting that intense EBV surveillance should occur early post-transplantation.
Electronic shell structure in the ionization potentials of copper clusters

Abstract The ionization potentials (IPs) of copper clusters (Cu n ) up to 150 atoms have been bracketed using laser photoionization. Large decreases in IP at n = 2, 8, 20, 30, 34, 40 and 60 atoms are observed, as well as a strong odd—even alternation extending beyond 100 atoms. These features correspond to electronic shell and subshell closings predicted for systems of n valence electrons confined to spherical or spheroidal potentials. The decreases in IP expected to accompany shell closings at n = 58 and 92 are absent, however, and a new set of local extrema are observed, including local maxima at n = 57 and 88–91 and minima at n = 49 and 92. The possibility of perturbations to the electronic energy level structure due to geometric packing constraints is discussed.
Ground resistance of concrete foundations in substation yards

The reinforced concrete foundations in a substation yard have extensive reinforcing steel in metallic connection with the ground conductor. The foundations may contribute significantly to the dissipation of the fault and leakage currents. Simple-to-use equations and graphs are presented to determine the ground resistance of various types of foundation encountered in substation yards. The validity of the analytical approach has been verified with scale model tests. The ground resistance of the foundations, estimated as suggested in the paper, can be used to evaluate the role of the foundations as a grounding element. >
Patella lead x-ray fluorescence measurements are independent of sample orientation.

In vivox-ray fluorescence bone lead measurements assess long-term lead exposure. Tibia, calcaneus, and patella are the most commonly sampled bones. Patella measurements also include lead signals from the distal femur, proximal tibia, and synovium. It is therefore important to know whether the orientation of the patella relative to the measurement system substantially affects the measured patella lead concentrations and their measurement uncertainties. This study examined whether these parameters exhibited a dependence on the orientation of the patella with respect to the measurement system, a dependence that could arise from varying nonpatella contributions. There was no effect of orientation on measured patella lead concentration, but there was a highly significant effect of orientation on the measurement uncertainty. These data do not conclusively show that there are no nonpatella contributions to a patella lead measurement; rather, that any such contributions are not a function of measurement orientation over the range of orientations considered. Further study is required if the contribution of nonpatella tissues to a patella lead XRF-measured concentration is to be fully addressed. This study also filled a gap in the literature by quantifying the within-patella (29%) and between-patella (71%) variability of measured patella lead concentrations from replicate measures of nine patellae.
Circulation and hydrography in the northwestern Gulf of Alaska

Abstract Hydrography and satellite-tracked drifters from the Gulf of Alaska Recirculation Study (GARS) were used to describe the regional circulation from 1986 to 1989 in the northwest Gulf of Alaska. The average baroclinic transport (0/1000 db) from six occupations of a section across the Alaska Stream near the Shumagin Islands (55°N, 160°W) was 7.4 Sv. The seasonal variation in the transport of the Alaska Stream was negligible relative to the seasonal variation of the Sverdrup transport in the Gulf of Alaska as calculated from the wind-stress curl. However, the mean transport agreed with mean annual Sverdrup transport. Anticyclonic mesoscale eddies frequently appeared in the dynamic topography and hydrography along the easternmost sections of the cruise grid (140°W). Drifters released in the Alaska Stream offshore of Kodiak Island usually moved southwestward following the isobaths. However, the trajectories of four drifters from 1988 to 1989 described an anticyclonic meander in the Alaska Stream that propagated southwestward at about 0.022 m s−1. The hydrography confirmed the existence of the meander off Kodiak Island in April 1988. The temperature and salinity characteristics of the anticyclonic meanders and eddies indicated that the water masses at the center of the features were derived from Alaska Current water. Two mechanisms of enhanced vertical mixing in the Gulf of Alaska are suggested by the hydrography. The first one is due to wind mixing of the water column by intense winter storms and subsequent outcropping of the 26.8 δφ isopycnal surface in the center of the Alaska Gyre: a mechanism originally proposed by Van Scoy et al. (Journal of Geophysical Research, 96, 16,801–16,810, 1991). The second one is associated with fine structure in the temperature and salinity profiles centered at a density of 26.8 δϑ, the approximate density of North Pacific Intermediate Water. These mechanisms freshen the water on the 26.8 δgj isopycnal surface. Subsequent lateral mixing on isopycnal surfaces by mesoscale eddy activity may contribute to the low salinity signature of the North Pacific Intermediate Water.
Bites of brown recluse spiders and suspected necrotic arachnidism.

Although much has been published about the pathophysiology and treatment of necrotic spider bites, therapeutic interventions continue without evidence-based justification.
Microchips for single atom detection and spin squeezing

Magnetic microtraps for ultracold atoms combine tight confinement, long storage times, high degree of control over the atomic position, and good optical access. Atom detection can be implemented via fluorescence, absorption, or dispersive measurements. All three types of measurements can be enhanced by an optical resonator, where the enhancement factor is proportional to the resonator finesse F. In the limit of negligible detector counts, in a setup where the detector registers n counts per atom in a fluorescence measurement, the atom number resolution is DeltaNf= (N/n)1/2 for a fluorescence measurement, and DeltaNa= (1/4N)1/2 for an absorption measurement. This means that absorption and fluorescence measurements perform similarly for one atom, but that the absorption measurement is superior for N >1. However, in absorption measurements the number of atoms must remain sufficiently small for the atomic absorption not to deteriorate the resonator finesse. Larger samples can be probed by dispersive measurements, where the tuning of the resonator due to the atomic index of refraction is measured. In the absence of technical noise, the corresponding atom number resolution is independent of detuning from the atomic transition, and given by DeltaNd= (1/n)1/2 . Using fluorescence detection in a resonator of finesse F=8000, we detect two counts per atom in 250 mus, enabling single-atom detection with 75% efficiency (Teper et al., 2006). Absorption detection with 3.3% transmission attenuation enables us to measure small samples with up to 10 atoms with a resolution of about one atom. Absorptive and dispersive detection are interesting in that the resolution is not decreased with higher atom number. The reason is that both rely on the forward scattered signal, where the fields emitted by different atoms add coherently. These methods therefore allow non-destructive measurements below the atom-number shot noise, provided that the optical depth of the sample exceeds unity. We have realized an optical depth of several thousand inside the resonator, which should enable trapped-atom detection significantly below the shot-noise limit. If the detection is applied in a state-selective manner to a sample of two-level atoms (Geremia et al., 2004), conditional spin squeezing results. Such squeezing of the pseudo-spin for an atomic clock transition can be used to realize a hyperfine atomic clock on a microchip (Treutlin et al., 2004) that operates below the atom number shot noise limit (standard quantum limit). We report experimental progress towards pseudo-spin squeezing for 87Rb atoms trapped on the microchip.
Statistical comparison of movement amplitudes from groupings of normal geriatric speakers.

An implicit assumption of many studies of articulatory kinematics is that all normal speakers are equivalent, at least in a statistical sense. The present report investigated this assumption by per...
PUBLIC ARCHITECTURE, RITUAL, AND TEMPORAL DYNAMICS AT THE MAYA CENTER OF BLUE CREEK, BELIZE

This paper summarizes more than a decade of excavations in the monumental core precinct of the Maya center of Blue Creek in northwestern Belize. Extensive and intensive excavations at Blue Creek have been undertaken since 1992. Consequently, a large database has been accumulated, particularly regarding the Early Classic period. Although occupation at Blue Creek dates to the Early Preclassic period (900 b.c.), complex society and, probably, the installation of Blue Creek's first king occurred at about a.d. 100, in the Late Preclassic period. For the next several hundred years, Blue Creek grew in population and complexity, finally being abandoned at some time in the ninth century a.d.
Analysis of Failure Time in Clonally Propagated Plant Populations

A problem originating in forest tree breeding concerns the number of clones needed in clonally propagated plantings to manage risk of failure due to an unforeseen catastrophic event. In this paper, we present a model for and analysis of time to failure for clonally propagated populations, assuming that in each year there is a chance for attack by an insect or pathogen. We develop the probability distribution of the number of years until population failure, T. A surprising finding is that in some circumstances increasing the number of clones can increase, rather than decrease, the chance of population failure. This suggests that laws, such as those current in the European Community, mandating minimum numbers of clones to be used in reforestation, may not achieve their intended effects, and that further investigation is needed to clarify the situation.
Effect of Surface Topography on the Relaxation Behavior of Thin Polysulfone Coatings on Pretreated Aluminum Substrates

Abstract Thin polysulfone (PSF) coatings on pretreated aluminum surfaces were characterized utilizing dielectric thermal analysis (DETA) to detect changes in the molecular motions and structural transitions in the PSF-Al interphase. The XPS results show that the interfacial chemistry between the PSF and the Al oxide surface was the same on both degreased and phosphoric acid anodized (PAA) Al surfaces. The order of the loss peak temperature of the PSF is, PSF coating on porous Al>PSF coating on smooth Al>neat PSF film. The activation energy of relaxation is also lower for neat PSF when compared with the thin film cast onto a smooth Al or a porous PAA Al substrate. The SEM photomicrographs revealed that the PSF uniformly coated the degreased substrate, whereas PSF filled the porous oxide on PAA Al surface and resulted in whisker-like structures.
Anelastic studies of intrinsic atomic defects

Abstract The use of the techniques of anelastic relaxation for the study of intrinsic point defects in metals is considered, with particular emphasis on defects produced by irradiation. The general principles of point defect relaxations, and the information about the defects which is obtainable from such studies, is first reviewed. Existing data, particularly for fcc and bcc metals, are then examined and interpreted. Relaxations attributable to close pairs and to isolated interstitials are identified and discussed. Other relaxations, which appear at higher temperatures, can be attributed to small interstitial clusters as well as to impurity-interstitial interactions. Finally, the author's assessment of fruitful directions for further investigation is presented.
Abuse potential evaluation of inhalants

Although inhalant abuse remains an important worldwide drug abuse problem, little is known about the relative abuse liability of specific inhalant compounds. This paper reviews approaches which might be used to investigate the abuse potential of inhalants in the laboratory, focusing primarily on animal studies. The principal approaches considered are inhalant self-administration and discrimination studies. A need is identified for further investigations of the abuse potential of inhalants to provide data which should be useful in shaping a more effective public health response to inhalant abuse.
Timing and executive function: Bidirectional interference between concurrent temporal production and randomization tasks

A review of interference effects in concurrent temporal/nontemporal dual-task studies suggests that prospective timing may be related to executive cognitive functions. Executive processes play a supervisory role in behavior by controlling attention, coordinating information, and scheduling actions. In the present research, a timing task was paired with an established executive task in a dual-task paradigm. The timing task required subjects to generate a series of 5-sec temporal productions, and the executive task was random number generation. These tasks were performed both separately and concurrently. Comparisons of single-task and dual-task conditions showed that (1) the randomization task interfered with timing by making temporal productions more variable and longer and (2) concurrent timing disrupted randomization performance by making responses less random. This pattern of bidirectional interference supports the idea that timing relies on the same attentional resources used by other executive-level tasks.
Mud into Shale: When and How?: ABSTRACT

Coring of surficial sediments on the sea floor to date has not revealed the presence of indurated, clayey sediments that are worthy of the name mudstone or shale, even though some clay as old as 50 million years has been recovered. In contrast, very young, argillaceous rocks on continental platforms are in many places indurated and cemented. Shale, in the sense of a fissile argillaceous rock, is uncommon in the younger part of the geological record though it is common in older rocks. Therefore, one can conclude that the induration to mudstone and the development of fissility of shale have two different time scales and thus result from two different processes. The initial process of induration is clearly linked to simple mechanical compaction under load where water can be expelled, as studies of marine sediments have shown. During this stage there is little gross mineralogical or chemical change in the sediment. Later stages include chemical additions that fill pore space and increase bulk density. Chemical additions are restricted to sediments that do not remain buried permanently under deep water; the additions result from ground-water movement through the mud, a movement that is initiated by the bed being raised above sea-level and thus making possible a hydraulic head in the outcrop area. Much of the chemical precipitation in this stage is simply redistribution of carbonate, but small amounts of silica generally are added too. Fissility, as was noted long ago, is correlated directly with the growth of phyllosilicate minerals in the ab plane, parallel with the bedding. It appears that the 10 A.U. micas and the chlorites are the principal causes of fissility. Accompanying this growth is a general increase in cementation that reduces porosity to low levels. However fissility does not always accompany cementation. Fissility, then, is the result of preferential growth of the 10 A.U. micas and the chlorites under load that is induced by the geochemical environment. That environment may be characterized as one whose K+/Na+, Mg++/Na+, and alkali/H+ ratios are relatively high compared with sea water, and whose dissolved silica concentration is close to that in equilibrium with quartz. The environment that has these characteristics is that of concentrated subsurface brines typical of most ancient sedimentary basins. The correspondence of the time scales of the production of fissility in shales and the formation of brines is important support for this hypothesis. End_of_Article - Last_Page 635------------
Diagnostic Testing Unwarranted for Children With Blood Lead 10 to 14 μg/dL

Background. Recent statements from the American Academy of Pediatrics and Centers for Disease Control and Prevention recommend diagnostic venous blood lead testing within 90 days of a marginally elevated screening test (10–14 μg/dL). Objective. To evaluate the ability of a marginally elevated capillary (CScr) or venous (VScr) blood lead screening test to predict venous diagnostic (VPb) blood lead (taken within 90 days of the screening test) that would prompt environmental evaluation (≥20 μg/dL). Design. Population-based follow-up study comparing CScr and VScr with VPb drawn within 90 days of the screening sample. This study population was drawn from all children aged 0 to 4 years who were screened in Worcester County, Massachusetts, and Providence County, Rhode Island, with CScr and VScr during calendar year 1994. Outcome Measures. To evaluate predictive validity, CScr and VScr were correlated with VPb. CScr, VScr, and VPb results were then separated into the following categories: Results. Of 31 904 children screened with CScr, 5450 (17.1%) were elevated and 1278 were followed up with VPb within 90 days. Of 14 623 children screened with VScr, 2979 (20.4%) were elevated and 614 were followed up with VPb within 90 days. CScr was only weakly correlated with VPb ( r = 0.39), whereas VScr was more strongly correlated with VPb ( r = 0.73). Compared with CScr Conclusions. These data indicate that special diagnostic testing within 90 days for children with CScr and VScr in the 10 to 14 μg/dL range does not result in greater identification of VPb ≥20. Raising the set point for diagnostic testing to 15 μg/dL in this sample would eliminate the unnecessary follow-up of 5162 children, of whom 3360 were falsely misclassified as having undue lead exposure.
Effect of Porosity Gradient in Gas Diffusion Layer on Cell Performance With Thin-Film Agglomerate Model in Cathode Catalyst Layer of a PEM Fuel Cell

A one-dimensional, steady-state, two-phase, isothermal numerical simulations were performed to investigate the effect on cell performance of a PEM fuel cell under non-uniform porosity of gas diffusion layer. In the simulation, the non-uniform porosity of gas diffusion layer was taken into account to analyze the transport phenomena of water flooding and mass transport in the gas diffusion layer. The porosity of the gas diffusion layer is treated as a linear function. Furthermore, the structure of the catalyst layer is considered to be a cylindrical thin-film agglomerate. Regarding the distribution analysis of liquid water saturation, oxygen concentration and water concentration depend on the porosity of gas diffusion layer. In the simulation, the eCG and eGC represent the porosity of the interfaces between the channel and gas diffusion layer and the gas diffusion layer and the catalyst layer, respectively. The simulation results indicate that when the (eCG , eGC ) = (0.8, 0.4), higher liquid water saturation appears in the gas diffusion layer and the catalyst layer. On the contrary, when the (eCG , eGC ) = (0.4, 0.4), lower liquid water saturation appears. Once the liquid water produced by the electrochemical reaction and condensate of vapor water may accumulate in the open pores of the gas diffusion layer and reduced the oxygen transport to the catalyst sites. This research attempts to use a thin-film agglomerate model, which analyze the significant transport phenomena of water flooding and mass transport under linear porosity gradient of gas diffusion layer in the cathode of a PEM fuel cell.Copyright © 2011 by ASME
Canonical forms for systems with time delay

In this paper, a canonical form for state-space representation of time-delay systems will be derived. The approach taken here is to convert the state-space representation into a set of ordinary differential-difference equations of particular form and then synthesize such equations back to the canonical structure. Emphasis will be given to the simple cases of second and third order scalar time-delay systems.
A model of exporting country response to the threat of a foreign import quota

When a country is threatened with a quota on one of its exports, one would expect that it not increase those exports. The historical record, however, suggests that countries often increase their exports following a threat. Such behavior is rational if there is growth in the export industry or a perception that increasing exports will allow a larger base from which to negotiate when the time actually comes to accept a VER. The effects of adjustment costs in production and market power in the exporting industry are discussed, as are optimal policy instruments in response to such a threat.
Regulation of Bax by c-Jun NH2-terminal kinase and Bcl-xL in vinblastine-induced apoptosis.

Microtubule inhibitors, such as vinblastine, are widely used in cancer chemotherapy. Vinblastine exerts its antitumor effect by inducing apoptosis. In KB-3 cells, we have shown previously that vinblastine activates c-Jun NH2-terminal protein kinase (JNK) and causes Bax mitochondrial translocation and activation. In this study, we sought to test the hypothesis that JNK and Bcl-xL act as positive and negative regulators, respectively, of Bax translocation. The JNK inhibitor SP600125 inhibited vinblastine-induced JNK activation and in concert inhibited Bax mitochondrial translocation, Bax oligomerization, and Bax activation. Furthermore, the JNK inhibitor blocked vinblastine-induced apoptosis. The ability of vinblastine to induce Bax translocation and the inhibitory effect of SP600125 were confirmed in cells stably expressing GFP-Bax. However, if transiently overexpressed, Bax localized to the mitochondria, and this was associated with loss of viability and subsequent cell death. If Bcl-xL was co-expressed with Bax, the cells readily tolerated Bax overexpression. Indeed, physical interaction between Bcl-xL and Bax but not Bak was demonstrated by co-immunoprecipitation. These findings provide novel insight into the role of Bax and its regulation in vinblastine-induced apoptosis.
Structural Organization of the Human Gene ( PKR ) Encoding an Interferon-Inducible RNA-Dependent Protein Kinase (PKR) and Differences from Its Mouse Homolog

Abstract The gene encoding the interferon-inducible, RNA-dependent protein kinase (PKR) was isolated as λ phage and P1 phage clones from human genomic DNA libraries and characterized by Southern blot and nucleotide sequence analyses. Southern blot analyses were consistent with a singlePKRgene, and genomic clones colocalized by fluorescencein situhybridization to human chromosome 2p. Sequence analysis demonstrated that the humanPKRgene consists of 17 exons and spans about 50 kb. The AUG translation initiation site for the 551-amino-acid PKR protein was located in exon 3; exon 17 was the largest exon and included the UAG translation termination site, AUUAAA polyadenylation signal, and putative C(A) 3′ cleavage site. Two RNA-binding motifs, RIand RII, were present in exons 4 and 6, respectively, and the codon phasing of these exon junctions was conserved between them. The organization of the regulatory and catalytic subdomains of the PKR protein was remarkably preserved between the human and the mousePKRgenes; the amino acid junction positions for 13 of the 15 protein coding exons were exactly conserved.
Amebic abscess of the liver in an infant.

Summary A case of acute amebic abscess of the liver with associated pneumonitis and intestinal amebiasis is presented in a white male infant, aged 17 months.
Epithelial Phosphatidylinositol-3-Kinase Signaling Is Required for β-Catenin Activation and Host Defense against Citrobacter rodentium Infection

Citrobacter rodentium infection of mice induces cell-mediated immune responses associated with crypt hyperplasia and epithelial β-catenin signaling. Recent data suggest that phosphatidylinositol-3-kinase (PI3K)/Akt signaling cooperates with Wnt to activate β-catenin in intestinal stem and progenitor cells through phosphorylation at Ser552 (P-β-catenin(552)). Our aim was to determine whether epithelial PI3K/Akt activation is required for β-catenin signaling and host defense against C. rodentium. C57BL/6 mice were infected with C. rodentium and treated with dimethyl sulfoxide (DMSO) (vehicle control) or with the PI3K inhibitor LY294002 or wortmannin. The effects of infection on PI3K activation and β-catenin signaling were analyzed by immunohistochemistry. The effects of PI3K inhibition on host defense were analyzed by the quantification of splenic and colon bacterial clearance, and adaptive immune responses were measured by real-time PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Increased numbers of P-β-catenin(552)-stained epithelial cells were found throughout expanded crypts in C. rodentium colitis. We show that the inhibition of PI3K signaling attenuates epithelial Akt activation, the Ser552 phosphorylation and activation of β-catenin, and epithelial cell proliferative responses during C. rodentium infection. PI3K inhibition impairs bacterial clearance despite having no impact on mucosal cytokine (gamma interferon [IFN-γ], tumor necrosis factor [TNF], interleukin-17 [IL-17], and IL-1β) or chemokine (CXCL1, CXCL5, CXCL9, and CXCL10) induction. The results suggest that the host defense against C. rodentium requires epithelial PI3K activation to induce Akt-mediated β-catenin signaling and the clearance of C. rodentium independent of adaptive immune responses.
Totally pure sequences and totally pure projection

All groups in this paper are Abelian. The notation is similar to Fuchs (1970) and Maclane (1963).
NEGATIVE NORM STATES, SUPERSELECTION RULES, AND THE LEPTON FAMILY

Field theories containing states of both positive and negative norm are considered. With the correct definition of the number operators for the quantum fields, all physical quantities are rendered canonically normalized. If the theory admits a global symmetry leading to a superselection rule which forbids transitions between positive- and negative-norm states, then the negative-norm states are allowed to be physical. Specifically, a spinor theory with higher-order field equations and multiple excitations is considered and applied to the charged lepton system: e,..mu..,tau. In this model, the negative norm of the muon state allows us to understand the nonexistence of ..mu -->..e..gamma.. decay. For minimal coupling, the theory is renormalizable and equivalent to three separate fermion electrodynamics with the additional prediction of equal charge for the leptons. A further anomalous magnetic moment coupling can only allow one of the decays tau..--> mu gamma.. or tau..-->..e..gamma...
Principal component analysis for clustering gene expression data.

Motivation: There is a great need to develop analytical methodology to analyze and to exploit the information contained in gene expression data. Because of the large number of genes and the complexity of biological networks, clustering is a useful exploratory technique for analysis of gene expression data. Other classical techniques, such as principal component analysis (PCA), have also been applied to analyze gene expression data. Using different data analysis techniques and different clustering algorithms to analyze the same data set can lead to very different conclusions. Our goal is to study the effectiveness of principal components (PCs) in capturing cluster structure. Specifically, using both real and synthetic gene expression data sets, we compared the quality of clusters obtained from the original data to the quality of clusters obtained after projecting onto subsets of the principal component axes. Results: Our empirical study showed that clustering with the PCs instead of the original variables does not necessarily improve, and often degrades, cluster quality. In particular, the first few PCs (which contain most of the variation in the data) do not necessarily capture most of the cluster structure. We also showed that clustering with PCs has different impact on different algorithms and different similarity metrics. Overall, we would not recommend PCA before clustering except in special circumstances.
Chronic effects of the photoenhanced toxicity of anthracene on Daphnia magna reproduction

The chronic effects of exposure to anthracene and ultraviolet radiation (UVR) on Daphnia magna reproduction were investigated. D. magna were exposed to anthracene in the presence or absence of ecologically relevant intensities of UVR for 21 d. Exposure to 8.2 μg/L anthracene in the absence of UVR significantly reduced the number of neonates produced by 13.8%; however, exposure to UVR in the absence of anthracene had no significant effect on the fecundity of D. magna. Concurrent exposure of D. magna to UVR and anthracene resulted in further reduced survival and fecundity. Exposure of D. magna to 7.2 μg/L anthracene and 117 μW/cm2 UV-A radiation resulted in 70% mortality or a 69% decrease in production of neonates by D. magna that survived. The reduction in fecundity was proportional to both anthracene concentration and UVR intensity. Equations were developed that predict the relative percent reduction in production of neonates due to the photoenhanced toxicity of anthracene given a particular anthracene concentration and UVR intensity.
Real-time dynamic focusing through tissue inhomogeneities during hyperthermia treatments with phased arrays

A needle probe hydrophone array made of discrete PVDF elements has been designed and fabricated at our laboratory. Such a probe can obtain complex acoustic pressure measurements at or near the tumor site. To extend the region over which these measurements may be used to focus a phased array, a real-time measurement system is needed, along with a method of extrapolating the data to points other than those measured by the probe. We describe such a real-time dynamic focusing algorithm that uses measurements from the full-set of hydrophone array elements in estimating the bearing and range of the elements of the transmitting array. In this way, a measurement of the radius of curvature of the wave front due to an array element is made along the span of the array, which extends the region of reliable refocusing. An outline of the steps of the refocusing algorithm along with simulation and experimental results are given. Finally, we describe the architecture of a real-time system for refocusing currently being designed for this purpose
Neurodevelopment in children with albinism.

Objectives To evaluate neurologic development in children with albinism. Design Observational cohort series. Participants and/or Controls Seventy-eight children with albinism, ages 4 to 18 years. Methods Parents completed a developmental questionnaire and were interviewed to evaluate their child for attention deficit hyperactivity disorder (ADHD) utilizing Diagnostic and Statistical Manual IV criteria. Sixty-five children underwent neurologic evaluation of balance and fine and gross motor movements. Results were compared with age-appropriate norms. Standardized reading tests were administered to 44 children. Each of 7 neurodevelopmental parameters were compared in terms of binocular best-corrected visual acuity (BCVA) using the nonparametric Wilcoxon rank-sum test. Main Outcome Measures Seven neurodevelopmental parameters were measured, including onset of walking, tandem gait, repetitive finger movements, sequential finger movements, standing on one foot, hopping on one foot, and throwing a ball overhand. School performance, reading performance, and presence of ADHD were also measured. Results The BCVA ranged from 20/20 to 20/800, with median of 20/150. A diagnosis of ADHD was present in 21.8% and pervasive developmental disorder was noted in three children (3.8%). No significant developmental delays were noted in the majority of children. Motor development was generally within the normal range and unaffected by severity of visual impairment. Parents reported that 82% performed at grade level in math and 74% at grade level in reading. Only 18% scored below average on standardized reading tests. Conclusions Most children with albinism have normal neurologic development despite visual impairment and increased prevalence of ADHD. Financial Disclosure(s) The authors have no proprietary or commercial interest in any materials discussed in this article.
Influence of Symbiotic Fungal Colonization on Oak Seedling Growth and Suitability for Insect Herbivory

Symbiotic ectomycorrhizal fungi enhance plant nutrient uptake and growth, especially in nutrient-poor conditions. The changes in plant metabolism due to mycorrhizal colonization could lead to alterations in plant suitability for herbivory. I investigated the effects of these fungal symbionts on oak, Quercus, growth and insect herbivory, and assessed the extent to which herbivore performance was affected by mycorrhizal colonization due to shifts in plant carbon allocation. Northern red oak, Quercus rubra L., acorns were inoculated with the ectomycorrhizal fungus, Pisolithus tinctorius (Persoon), and planted in either a nutrient-rich peat:perlite mixture or a nutrient-poor mine spoil:sand mixture. Plants were grown under greenhouse conditions for 45 d, after which seedling productivity was measured and herbivore performance trials were conducted. Gypsy moth, Lymantria dispar (L.), caterpillars were allowed to feed for the duration of the third instar, and performance was measured. Nonmycorrhizal, nutrient-poor plants had the lowest height growth, and produced the fewest leaves with the lowest leaf area and leaf mass, when compared with plants in the other treatments. Seedlings colonized by fungal symbionts showed enhanced productivity relative to noncolonized seedlings in several respects, including the number of leaves produced, leaf area, and basal stem diameter. Acorns grown in nutrient-rich substrate had a greater number of leaves, leaf area, leaf mass, and leaf area ratio, when compared with acorns grown in nutrient poor substrate, regardless of colonization status. Caterpillar growth and consumption rates were lowest on nutrient-rich, mycorrhizal plants, suggesting that colonized plants decrease herbivore performance in nutrient-rich conditions, when mycorrhizae are functioning parasitically. The data do not support the hypothesis that herbivore performance would increase on nutrient-poor, mycorrhizal plants, when mycorrhizal colonization provides the greatest benefits to the host plant.
Evaluation of Techniques for Detection of Carbapenem-Resistant Klebsiella pneumoniae in Stool Surveillance Cultures

Screening for gastrointestinal colonization with multidrug-resistant nosocomial pathogens is an important component of infection control protocols. In the New York City region, carbapenem-resistant Klebsiella pneumoniae strains, which harbor the KPC carbapenem-hydrolyzing β-lactamase, have rapidly emerged. The potential utility of screening medium, which involved using 10-μg imipenem disks, was investigated. The method of placing a sample from a fecal surveillance culture into broth containing an imipenem disk appeared to have the greatest sensitivity for detecting KPC-producing K. pneumoniae. Gastrointestinal colonization with two other carbapenem-resistant nosocomial pathogens, Pseudomonas aeruginosa and Acinetobacter baumannii, was also detected using this method. Placing fecal surveillance specimens into broth containing an imipenem disk is an easy method for screening samples for carbapenem-resistant nosocomial pathogens.
DEMOGRAPHY, GENETICS, AND THE VALUE OF MIXED MESSAGES

Abstract Iverson et al. (2004) used estimates of the homing rate for molting adult Harlequin Ducks (Histrionicus histrionicus) in Alaska to draw inferences about population structure. Homing rates, defined as one minus the ratio of birds recaptured elsewhere to those recaptured at the original banding site, were high (0.95–1.00) for males and females. Iverson et al. (2004) concluded that these high rates of homing are indicative of demographic independence among molting groups separated by small distances (tens to hundreds of kilometers) and that conservation efforts should recognize this fine-scale population structure. We re-examined their use of the homing rate, because their assumption of equal detection probability across a wide sampling area could have led to an upward bias in their estimates of site fidelity. As a result, we are hesitant to agree with their conclusion of high adult homing to molting areas and that molt-site fidelity is evidence for demographic independence. Our hesitancy stems from...
Anti-Immigrant Sentiment, Policy Preferences and Populist Party Voting in Australia

Immigration has become a highly salient political issue in many of the world's affluent democracies. Yet, the electoral dynamics of anti-immigrant sentiment remain barely understood. We distinguish two dimensions of concern about immigrants: material threat and cultural threat, and hold that the influence of both on the right-wing populist party vote is critically mediated by policy preferences to restrict immigration and to isolate Australia from foreign influence. The result is a path model of voting that allows material and cultural threat to influence policy preferences about how to deal with the ‘immigrant problem’, and allows both threat and policy preferences to affect voting for the far-right One Nation party in Australia. Our results confirm that popular concern about immigrants is multi-dimensional and that its two dimensions have different sources. We also demonstrate that anti-immigrant sentiment works indirectly through policy orientations to influence vote choice. Feelings about immigrants, in other words, have an electoral effect only when there is a good fit between the policy stances of voters and the policies promoted by the parties on offer.