cssi/SciSciGPT-SciSciNet huggingface dataset:
Factors dominating the transport critical current behavior in high-T C superconductors

The previous experimental studies on transport Jc and grain boundary (micro)structure of YBa2Cu3Ox have been summarized. A novel interpretation is proposed for the transport current behavior in high-Tc superconductors. Based on extensive transport, magnetization, and electron microscopy experimental data reported previously, we show that the transport Jc(H) characteristics in high-Tc superconductors are dominated by the portion of strongly coupled regions at the grain boundaries. As a result of inhomogeneity of the grain boundaries, the coupling strength varies and causes a distribution of Jgo (inter-granular Jc) related to the fluctuations of the superconducting order parameter at the boundary area. We also discuss formation mechanisms of strongly coupled regions in bulk materials, and we present inductive methods that can be used to determine the coupling strength of a material.
A C-terminal PDZ motif in NHE3 binds NHERF-1 and enhances cAMP inhibition of sodium-hydrogen exchange.

NHERF-1, a protein adapter containing two tandem PDZ domains, was first identified as an essential cofactor required for the phosphorylation and downregulation of NHE3 activity in response to elevated intracellular cAMP. NHERF-1 contains multiple protein interaction domains, but the mechanism by which it binds NHE3 remains unknown. Yeast two-hybrid analyses demonstrated that the C-terminal sequence, STHM, of NHE3 constitutes a PDZ motif critical for its association with NHERF-1. In this assay, NHE3 bound both PDZ-I and PDZ-II when presented as isolated domains, but mutations of the individual PDZ domains in the full-length NHERF-1 suggested a significant preference of NHE3 for the PDZ-II domain. To investigate NHERF-1/NHE3 association in cells, NHERF-1 complexes were isolated from PS120 cells expressing hexahistidine-tagged NHERF-1 and NHE3 using nickel-NTA−agarose. In these experiments, mutating the C-terminal PDZ motif still allowed NHE3 binding to NHERF-1, suggesting the presence of additional mechanis...
Allergen exposure and the development of specific IgE

Summary The increasing prevalence of asthma is associated with a concurrent rise in the prevalence of other atopic diseases. Common to these problems is the acquisition of specific IgE to allergens. The reason for the increase of sensitization to proteins in the environment is not entirely clear. Exposure has certainly increased due to changes in lifestyle which have facilitated allergen concentrations in indoor environments as well as increased the time spent indoors. This combination has increased allergen exposure which in turn has probably recruited individuals with lower degrees of genetic susceptibility into the pool of allergic individuals. However, specific sensitization does not always parallel allergen exposure even in large populations who are genetically similar. This suggests that other factors are involved in the development of atopy. Many candidates have been proposed which are either pro-allergic (pollution, passive smoke), anti-allergic (large family size) or both depending on the situation (viruses). Until there is definitive proof and therefore specific remedy, there is still some evidence that avoidance of exposure in young children may prevent the acquistion of specific IgE and the consequences of allergic disease.
Wage determination in U.S. manufacturing 1958–1976: A collective bargaining approach

This paper presents a cross-section collective bargaining approach to the analysis of inter-industry wage movements of production workers in U.S. manufacturing over the period 1958–1976. A Hicksian model is used to classify the determinants of wage change according to their likely influence on the concession and strike costs of management and unions. Three variables which are classified as management concession and strike costs are consistently significant in empirical testing: change in value productivity, labor intensity, and the profit rate. On the basis of this finding it is suggested that inter-industry wage changes are generally a function of management concession costs.
Lamb wave behavior in bridge girder geometries

Lamb waves in plates and in cylindrical pipes have been the subject of extensive study, largely because they propagate great distances with little attenuation, and can therefore be used to detect flaws. In this paper we report finite element simulations and experimental studies of Lamb waves in steel bridge girder geometries. In our studies the Lamb waves are generated by PZT wafer-type transducers mounted on the girder web, driven by a windowed sinusoidal pulse; the pulse center frequency is chosen to yield a frequency-thickness product of roughly 1 MHz-mm, at which the group velocities of the S0 and A0 waves are well separated, and at which waves in higher modes are theoretically absent. Transient dynamic finite element simulations, both in 2D and in 3D, were performed using FEMLAB and ABAQUS. The simulations show that transmission at the web-flange joint creates guided waves in the flanges that travel at different velocities from the Lamb waves in the web, and that reflection at the web-flange joint creates a largely straight-crested wavefront for the Lamb waves in the web remote from the source. Simulation studies also illustrate the acoustic influence of plate girder transverse stiffeners, which is observed to be relatively small. A welded steel plate girder laboratory specimen was fabricated with proportions typical of highway bridge members, at approximately half-scale. The web height is 920 mm and thickness is 3.2 mm, for a representative height-thickness ratio of 288; the flange width is 100 mm and thickness is 6.4 mm, for a representative width-thickness ratio of 16. Small PZT transducers, roughly 6.4 x 6.4 x 0.6 mm, excited at less than 10 V, produce ample signals. We compare simulation results and experimental measurements for Lamb wave illumination of the plate girder segment. We also discuss the detection of cracks, simulated experimentally by saw cuts of varying dimensions in the laboratory girder specimen.
Carbon-13 NMR studies of amino acids: Chemical shifts, protonation shifts, microscopic protonation behavior

The 13C chemical and protonation shifts of a number of the naturally occurring α-amino acids and some related compounds are tabulated. A computer program is described which fits chemical shift vs pH data to predict the macroscopic pKa values. This program operates on the data in a global manner utilizing simultaneously all of the 13C resonance data at the various pH conditions in order to achieve a self-consistency in the calculated pKa values. The protonation shifts and pKa values thus obtained are used to determine the microscopic protonation behavior of lysine and hydroxylysine; it was found to be necessary to use model compounds to ascertain the influence of amine protonation on the chemical shifts of remote carbons in the latter systems. Only in this way could these microscopic protonation equilibria be properly characterized.
Sixteenth century printed editions of xenophon's hellenica

The latest critical texts of Xenophon's Hellenica have been strongly influenced by early printed editions, although little is known about how the latter were established. This article shows how the editio princeps was based upon relatively poor manuscript witnesses. Successive editions did little to improve the text until Stephanus and Leonclavius introduced new readings from better manuscripts along with interpolations drawn from their own studies and those of other contemporaneous scholars.
DNA-dependent RNA polymerases isolated from yeast mitochondria.

Abstract Purified preparations of yeast mitochondria yield three species of DNA-dependent RNA polymerases. These enzymes have been separated and purified to homogeneity for analysis of their properties and for comparison with the properties of nuclear preparations of yeast RNA polymerases. Three enzymes have been separated by DEAE-Sephadex chromatography of each fraction. Both nuclear and mitochondrial preparations yield three components with nearly identical elution properties. The distributions of enzyme activity on DEAE-Sephadex chromatography differ with the three nuclear peaks, being found in ratios (uncorrected for the effect of increasing salt concentration) of 8:85:7 and the mitochondrial peaks in ratios of 8:32:60 at late log phase of growth under optimized conditions in which protease inhibitors and an antioxidant were included. The type of mitochondrial enzymes in 3-day-old cells differed from those grown to late logarithmic phase. It has been established that the enzymes of the mitochondrial preparation are associated with the membrane fraction. While extraction with 0.5 m KCl solubilizes considerable enzyme activity, greatly enhanced yields of enzyme MIII are obtained by addition of the antioxidant 2,6-di-t-butyl-4-hydroxymethyl phenol during enzyme extraction. Inhibition of protease activity has also been shown to have a major effect on the yield and distribution of enzymes obtained from mitochondrial preparations. The mitochondrial preparations of yeast polymerases are generally similar but not identical to corresponding nuclear polymerases in subunit molecular weights, inhibitor sensitivities, and in DNA template dependence. Comparative studies of nuclear and mitochondrial polymerases clearly establish that differences do exist among the isolated enzymes of these classes. It has not been ruled out to date that these enzymes may be derived in part or in total from the same cytoplasmic subunit pool, nor has it been established that any of these enzymes function in mitochondria in vivo.
IN-LINE FIBER EVANESCENT FIELD ELECTROOPTIC MODULATORS

Electrooptic modulators that consist of an optical fiber waveguide coupled to an electrooptic waveguide are reviewed. Desirable attributes of these devices are that the optical fiber is uninterrupted and the interaction with the electrooptic region occurs only where the optical properties are modulated. In this paper we review in-line fiber evanescent field modulators that we have implemented with electrooptic polymers and compound semiconductor quantum wells. We show that the beam propagation method can accurately simulate the behavior measured in these devices.
Radioimmunoassay measurement of ACTH-facilitated PGE2 and PGF2α release from isolated cat adrenocortical cells

Prostaglandin (PG) biosynthesis by trypsin-dispersed cat adrenocortical cells was studied by radioimmunoassay (RIA). Parallel assays of incubation media using PGF2alpha and PGF1alpha antisera established that PGF2alpha is the primary PGF released by feline cortical cells. Following the reduction of PGE to PGF with sodium borohydride (NaBH4) these same two antisera were also used to identify PGE2 as the primary PGE released. RIA using a PGE antiserum confirmed the presence of PGE in the incubation medium. Steroidogenic concentrations of ACTH (50-250muU) enhanced PGE and PGF release, and indomethacin suppressed the ACTH-facilitated release. These studies provide additional evidence for ACTH-induced PG synthesis by feline cortical cells, and support the hypothesis that PGs play some role in the steroidogenic action of ACTH.
Coupling of Magnons and Phonons at High Frequencies

A calculation is given describing the coupling of magnons and phonons, for a general wave vector, in a simple cubic ferromagnetic lattice. The source of magnetoelastic coupling is taken as the strain (or displacement) dependence of the magnetic dipole-dipole energy, or Van Vleck's pseudodipolar energy. Particular solutions of the secular equation, describing the dispersion relation, are given for k ‖ z, z being the direction along which the spins are aligned. Zur Beschreibung der Kopplung von Magnonen und Phononen wird eine Berechnung fur einen allgemeinen Wellenvektor in einem ferromagnetischen primitiv kubischen Gitter mitgeteilt. Als Quelle fur die magnetoelastische Kopplung wird die Verformungs- oder Verlagerungsabhangigkeit der magnetischen Dipol-Dipolenergie oder Van Vlecks-Pseudodipolenergie angenommen. Spezielle Losungen der Sakulargleichung, die die Dispersionsbeziehung beschreibt, werden fur k ‖ z gegeben, wobei z die Richtung ist, langs der die Spins orientiert sind.
GaInAs/GaAs Waveguide Modulators With Multiple Short-Period Strained-Layer Superlattice Quantum Wells

InGaAs/GaAs multiple quantum well (MQW) structures with wells that consist of InAs/GaAs short-period strained-layer superlattices (SPSLS) have shown sharp excitonic absorption peaks at room temperature, despite the high degree of strain.1 By using superlattices with multiple periods consisting of 2 monolayers of InAs and 5 monolayers of GaAs, dislocationfree InGaAs wells with 0.30 average In mole fractions have been obtained.2 We report the first MQW waveguide modulators based on these InAs/GaAs SPSLS quantum wells. These modulators demonstrate significant electro-absorption and electro-refraction effects at wavelengths between 1.00 and 1.06 µm. An advantage of such modulators is that they can be monolithically integrated with low-threshold-current InGaAs lasers as well as low-loss GaAs waveguides for various optical circuit applications. In addition, stronger electric-field dependences are expected for the wider wells permitted by the use of SPSLS.3
Nonfatal occupational fall injuries in the West Virginia construction industry

Descriptive analyses were conducted using the West Virginia workers' compensation and supplemental injury records to assess nonfatal occupational falls from elevated work surfaces in the construction industry. These analyses are based on the 182 fall injuries reported to the State workers' compensation during fiscal year 1991 for which there were complete supplemental injury data. County-specific injury rates were calculated for counties with six or more fall injuries. Most of these incidents occurred among young white males who were employed as either craftsmen and kindred workers (48%) or laborers (33%) on non-union jobs in the general construction category (SIC-15). The counties with the highest injury rates that exceed the State rate of 5.9 per 1000 construction workers were located around or near the major industrial areas of Kanawha and Monongalia counties. Of the 182 claimants in the study population, one-third had been employed in their occupation for 2 years or less. For 60% of the claimants, the length of employment with the company for which they were employed at the time of the fall injury was two years or less; 26% had been employed for six months or less. Approximately, 63% of the 182 claimants had received some type of fall protection training. Ladders and scaffolds were involved in 50% of all falls. Fall protection devices were not commonly used by the 182 construction workers who worked from elevated surfaces. Fifty percent of the claimants were using tools or handling materials when the fall occurred. Fifty-nine percent of the falls occurred from elevated work surfaces which were relatively low heights (< or = 10 feet) where few safety regulations apply even though the potential for a serious injury still exists.
Babies Who Are Small for Gestational Age

Small for gestational age (SGA) is a term applied to a heterogeneous population of babies who do not meet the expected growth parameters for their gestational age. The definition of SGA is variable, but the clinical definition used most often is any baby who weighs less than 2500 g and falls below the 10th percentile on the growth chart for its gestational age. These infants are at increased risk for hypoglycemia, polycythemia, and temperature instability and suffer higher neonatal mortality rates. Although they often are used interchangeably, the terms SGA and intrauterine growth retardation (IUGR) are not always synonymous. Approximately 60% of infants classified as SGA are constitutionally small babies who are small for gestational age but not growth retarded.
Expression of immunogenic VP2 protein of infectious bursal disease virus in Arabidopsis thaliana

VP2 protein is the major host-protective immunogen of infectious bursal disease virus (IBDV) of chickens. Transgenic lines of Arabidopsis thaliana expressing recombinant VP2 were developed. The VP2 gene of an IBDV antigenic variant E strain was isolated, amplified by RT-PCR and introduced into a plant expression vector, pE1857, having a strong promoter for plant expression. A resulting construct with a Bar gene cassette for bialaphos selection in plant (rpE-VP2) was introduced into Agrobacterium tumefaciens by electroporation. Agrobacterium containing the rpE-VP2 construct was used to transform Ar. thaliana and transgenic plants were selected using bialaphos. The presence of VP2 transgene in plants was confirmed by PCR and Southern blot analysis and its expression was confirmed by RT-PCR. Western blot analysis and antigen-capture ELISA assay using monoclonal anti-VP2 were used to determine the expression of VP2 protein in transgenic plants. The level of VP2 protein in the leaf extracts of selected transgenic plants varied from 0.5% to 4.8% of the total soluble protein. Recombinant VP2 protein produced in plants induced antibody response against IBDV in orally-fed chickens.
Shear stress increases inositol trisphosphate levels in human endothelial cells.

Abstract To elucidate some of the early mechanisms underlying the response of primary human endothelial cells to the initiation of flow, we investigated the changes in inositol lipid metabolism in cells exposed to arterial and venous levels of shear stress. We used a radioimmunoassay specific for inositol-1,4,5-trisphosphate (Ins1,4,5P3) to demonstrate that initiation of an arterial shear stress caused a rapid rise in Ins1,4,5P3 levels which peaked after approximately 30 seconds of flow (2.1±0.2 fold stimulation) and remained elevated for at least 6 minutes after the initiation of flow. This increased Ins1,4,5P3 concentration is similar in magnitude to the increase caused by 10 μM histamine (2.8±0.3 fold stimulation). Thus these cells may detect the presence of mechanical stress by a signal transduction pathway involving inositol lipid metabolism.
Placental growth factor provides a novel local angiogenic therapy for ischemic cardiomyopathy.

BACKGROUND Heart failure occurs predominantly due to coronary artery disease and may be amenable to novel revascularization therapies. This study evaluated the effects of placental growth factor (PlGF), a potent angiogenic agent, in a rat model of ischemic cardiomyopathy. METHODS Wistar rats underwent high proximal ligation of the left anterior descending coronary artery and direct injection of PlGF (n = 10) or saline as a control (n = 10) into the myocardium bordering the ischemic area. After 2 weeks, the following parameters were evaluated: ventricular function with an aortic flow probe and a pressure/volume conductance catheter, left ventricular (LV) geometry by histology, and angiogenesis by immunofluorescence. RESULTS PlGF animals had increased angiogenesis compared to controls (22.8 +/- 3.5 vs. 12.4 +/- 3.2 endothelial cells/high-powered field, p < 0.03). PlGF animals had less ventricular cavity dilation (LV diameter 8.4 +/- 0.2 vs. 9.2 +/- 0.2 mm, p < 0.03) and increased border zone wall thickness (1.85 +/- 0.1 vs. 1.38 +/- 0.2 mm, p < 0.03). PlGF animals had improved cardiac function as measured by maximum LV pressure (95.7 +/- 4 vs. 73.7 +/- 2 mmHg, p = 0.001), maximum dP/dt (4206 +/- 362 vs. 2978 +/- 236 mmHg/sec, p = 0.007), and ejection fraction (25.7 +/- 2 vs. 18.6 +/- 1%, p = 0.02). CONCLUSIONS Intramyocardial delivery of PlGF following a large myocardial infarction enhanced border zone angiogenesis, attenuated adverse ventricular remodeling, and preserved cardiac function. This therapy may be useful as an adjunct or alternative to standard revascularization techniques in patients with ischemic heart failure.
Corticotropin releasing factor-induced CREB activation in striatal neurons occurs via a novel Gβγ signaling pathway.

The peptide corticotropin-releasing factor (CRF) was initially identified as a critical component of the stress response. CRF exerts its cellular effects by binding to one of two cognate G-protein coupled receptors (GPCRs), CRF receptor 1 (CRFR1) or 2 (CRFR2). While these GPCRs were originally characterized as being coupled to Gαs, leading to downstream activation of adenylyl cyclase (AC) and subsequent increases in cAMP, it has since become clear that CRFRs couple to and activate numerous other downstream signaling cascades. In addition, CRF signaling influences the activity of many diverse brain regions, affecting a variety of behaviors. One of these regions is the striatum, including the nucleus accumbens (NAc). CRF exerts profound effects on striatal-dependent behaviors such as drug addiction, pair-bonding, and natural reward. Recent data indicate that at least some of these behaviors regulated by CRF are mediated through CRF activation of the transcription factor CREB. Thus, we aimed to elucidate the signaling pathway by which CRF activates CREB in striatal neurons. Here we describe a novel neuronal signaling pathway whereby CRF leads to a rapid Gβγ- and MEK-dependent increase in CREB phosphorylation. These data are the first descriptions of CRF leading to activation of a Gβγ-dependent signaling pathway in neurons, as well as the first description of Gβγ activation leading to downstream CREB phosphorylation in any cellular system. Additionally, these data provide additional insight into the mechanisms by which CRF can regulate neuronal function.
Concentrations of Tropospheric Ozone from 1979 to 1992 Over Tropical Pacific South America from TOMS Data

An estimate of tropospheric ozone concentrations was obtained from the difference in the Total Ozone Mapping Spectrometer (TOMS) data between the high Andes and the Pacific Ocean. From 1979 to 1992 the tropospheric ozone concentration apparently increased by 1.48 ± 0.40 percent per year or 0.21 ± 0.06 Dobson unit per year over South America and the surrounding oceans. An increase in biomass burning in the Southern Hemisphere can account for this trend in tropospheric ozone concentrations.
Organo-sulfur molecules enable iron-based battery electrodes to meet the challenges of large-scale electrical energy storage

Rechargeable iron–air and nickel–iron batteries are attractive as sustainable and inexpensive solutions for large-scale electrical energy storage because of the global abundance and eco-friendliness of iron, and the robustness of iron-based batteries to extended cycling. Despite these advantages, the commercial use of iron-based batteries has been limited by their low charging efficiency. This limitation arises from the iron electrodes evolving hydrogen extensively during charging. The total suppression of hydrogen evolution has been a significant challenge. We have found that organo-sulfur compounds with various structural motifs (linear and cyclic thiols, dithiols, thioethers and aromatic thiols) when added in milli-molar concentration to the aqueous alkaline electrolyte, reduce the hydrogen evolution rate by 90%. These organo-sulfur compounds form strongly adsorbed layers on the iron electrode and block the electrochemical process of hydrogen evolution. The charge-transfer resistance and double-layer capacitance of the iron/electrolyte interface confirm that the extent of suppression of hydrogen evolution depends on the degree of surface coverage and the molecular structure of the organo-sulfur compound. An unanticipated electrochemical effect of the adsorption of organo-sulfur molecules is “de-passivation” that allows the iron electrode to be discharged at high current values. The strongly adsorbed organo-sulfur compounds were also found to resist electro-oxidation even at the positive electrode potentials at which oxygen evolution can occur. Through testing on practical rechargeable battery electrodes we have verified the substantial improvements to the efficiency during charging and the increased capability to discharge at high rates. We expect these performance advances to enable the design of efficient, inexpensive and eco-friendly iron-based batteries for large-scale electrical energy storage.
Calcific Uremic Arteriolopathy (calciphylaxis): Case Series and Review of Clinical Features and Terminology

Abstract: We present 3 cases of calciphylaxis, better termed calcific uremic arteriolopathy (CUA), which illustrate typical and atypical presentations of this disorder to discuss its classification, pathophysiology, and treatment based on a review of the literature. Of the 3 patients presenting with biopsy-proven CUA, 1 patient with proximal lesions expired in the setting of upper gastrointestinal bleeding and superinfection of ulcers, a second patient had an extensive distal ulcerative lesion that failed to heal and necessitated lower-extremity amputation, and a third patient with multiple small distal lesions experienced complete resolution of the ulcers. The classification, pathophysiology, and treatment of CUA are detailed here. CUA is a heterogeneous syndrome which typically follows a progressive course leading to loss of life or limb. Diagnosis requires a high index of suspicion and low threshold for biopsy in at-risk patients. Parathyroidectomy is appropriate to rapidly lower the calcium-phosphorus product in the setting of marked hyperparathyroidism; additional therapy includes the avoidance of purported precipitants, medical lowering of the serum calcium and phosphorus, and promotion of wound healing with hyperbaric oxygen therapy.
Nerve growth factor: A key local regulator in the pathogenesis of inflammatory arthritis

Objective The effect of nerve growth factor (NGF) and its receptor (NGFR) in inflammatory diseases is a novel research field. The purpose of this study was to investigate the role of NGF/NGFR in human T cell subpopulations and fibroblast-like synovial cells (FLS) and examine its pathophysiologic significance in psoriatic arthritis (PsA) and rheumatoid arthritis (RA). Methods Expression of NGF/NGFR was examined in synovial fluid (SF), FLS, peripheral blood (PB)–derived T cells, and SF-derived T cells from patients with PsA, RA, and osteoarthritis (OA). NGF levels were determined by enzyme-linked immunosorbent assay. NGF-induced T cell/FLS proliferation was examined by MTT assay. Low-affinity (p75)/high-affinity (TrkA) NGFR expression was determined by high-dimensional fluorescence-activated cell sorting. A monochlorobimane assay was used to determine the effect of NGF on T cell survival. Results Levels of NGF were higher in SF samples from PsA and RA patients as compared to SF samples from OA patients. NGF-induced FLS proliferation was more marked in PsA and RA patients. TrkA was up-regulated on activated SF T cells from PsA (mean ± SD 22 ± 6.2%) and RA (8 ± 1.3%) patients, whereas in SF samples from OA patients, TrkA+CD3+ T cells were not detectable. NGF induced the proliferation of PB T cells, induced the phosphorylation of Akt in activated T cells, and consistent with known pAkt activity, inhibited tumor necrosis factor α–induced cell death in these T cells. Conclusion Based on our findings, we propose a model in which NGF secreted by FLS into PsA and RA synovium promotes the survival of activated autoreactive T cells as well as FLS proliferation. Thus, NGF has the potential to sustain the chronic inflammatory cascades of arthritis of autoimmune origin.
Intestinal paracellular peptide transport: mobilization of intracellular calcium as a mechanism of tight junctional opening by 4-phenylazobenzoxycarbonyl–Pro–Leu–Gly–Pro–d-Arg (Pz-peptide) in the rabbit descending colon and Caco-2 cell monolayers

Abstract The objective of this study was to test the hypothesis that 4-phenylazobenzoxycarbonyl–Pro–Leu–Gly–Pro– d -Arg (Pz-peptide) mobilized intracellular Ca 2+ in Caco-2 cell monolayers and the descending colon of the albino rabbit, thereby triggering tight junctional opening. Experiments in cell suspensions revealed that Pz-peptide indeed caused an increase in [Ca 2+ ] i in a concentration-dependent manner over the 1–10 mM range. Such an increase appeared to correlate with the transient rise in inositol-1,4,5-triphosphate (IP 3 ), a product of phosphoinositol-4,5-biphosphate (PIP 2 ) hydrolysis mediated by phospholipase C (PLC). The increase in [Ca 2+ ] i was inhibited by an intracellular Ca 2+ release blocker, TMB-8, thus supporting the notion of mobilization of Ca 2+ from intracellular stores. A possible link between the Na + channel and PLC activation by Pz-peptide was suggested by the lack of enhancement in IP 3 and [Ca 2+ ] i in the presence of either neomycin (a PLC inhibitor) or amiloride (a Na + channel blocker). Finally, blunting the rise in Ca 2+ and IP 3 concentrations by GDP β S (a non-hydrolyzable analog of GTP) raises the interesting possibility that a G-protein may be involved in the tight junctional opening triggered by Pz-peptide.
Structural and Thermodynamic Features of Spiroiminodihydantoin Damaged DNA Duplexes

Oxidation of guanine or 8-oxo-7,8-dihydroguanine can produce spiroiminodihydantoin (Sp) R and S stereoisomers. Both in vitro and in vivo experiments have shown that the Sp stereoisomers are highly mutagenic, causing G → C and G → T transversion mutations. Therefore, they are of interest as potential endogenous cancer causing lesions. However, their structural properties in DNA duplexes remain to be elucidated. We have employed computational methods to study the Sp lesions in 11-mer DNA duplexes with A, C, G, and T partners. Molecular dynamics simulations have been carried out to obtain ensembles of structures, and the trajectories were employed to analyze the structures and compute free energies. The structural and thermodynamic analyses reveal that the Sp stereoisomers energetically favor positioning in the B-DNA major groove, with minor groove conformers also low energy in some cases, depending on the partner base. The R and S stereoisomers adopt opposite orientations with respect to the 5‘ to 3‘ direct...
Laser-induced pH change in solution

Abstract First observations have been made of one-photon and two-photon absorption processes that induce pH changes in various solutions. The concentration of H + or negative ions such as Cl − was measured by selected ion electrodes. The quantum yields for one-photon absorption and two-photon-induced dissociation cross sections were also measured.
Hot Atoms and Cold Facts: Mysteries and Opportunties in Vibration-Assisted Surface Chemistry

Abstract This paper is a synopsis of the keynote lecture at the Third International Conference on Vibrations at Surfaces. The science of hot atoms at surfaces is divided into three broad areas: spectroscopy, theory, and process dynamics. A brief overview of each area is given in which the main advances and mysteries which have emerged during the past few years are noted. The resolution of such mysteries provides the traditional type of opportunity for scientific discovery. Most of the currently visible frontiers lie in the development of applications of the techniques of vibrational spectroscopy, however, so that these scientific opportunities tend to be different in kind than they were a decade ago. Another type of opportunity is the development of hot-atom process technologies. Inspection of current activity reveals that a gap exists between the development of the techniques of vibrational spectroscopy as applied to well-defined model systems and the systematic application of these techniques to examine and extend process technologies based on surface chemistry. Radiation-induced surface chemistry is an example of an area which affords a unique opportunity for surface vibrational spectroscopy and theoretical chemistry to play a significant role in the development of fabrication technologies for electronic devices. This type of opportunity is shown to be particularly important for the future of surface vibrational spectroscopy in the current economic climate for research and development.
On a Test of Independence in a Bivariate Exponential Distribution

Abstract The problem of testing independence in the bivariate exponential distribution of Marshall and Olkin is considered here with the assumption of identical marginal distributions. It is shown that in spite of the presence of a nuisance parameter, a uniformly most powerful test exists. The test turns out to be the same as the one proposed by Bernis, et al., on a heuristic basis. In addition to demonstrating the optimality property of the test, an easily computable expression is provided for the exact power function.
Nutrient loss with runoff from fairway turf: An evaluation of core cultivation practices and their environmental impact

The presence of excess nutrients in surface waters can result in undesirable environmental and economic consequences, including nuisance algal blooms and eutrophication. Fertilizer use in highly managed turf systems has raised questions concerning the contribution of nutrients to surrounding surface waters. Experiments were designed to quantify phosphorus and nitrogen transport with runoff from turf plots maintained as a golf course fairway to identify which cultural practice, solid tine (ST) or hollow tine (HT) core cultivation, maximized phosphorus and nitrogen retention at the site of fertilizer application. Simulated precipitation and collection of resulting runoff were completed 26 ± 13 h following granular fertilizer application (18-3-18: N-P2O5-K2O) and 63 d and 2 d following core cultivation. Runoff volumes were reduced in fairway turf plots aerated with HT relative to ST (63 d: 10%, 2 d: 55% reduction). Analysis of the runoff revealed a reduction in soluble phosphorus, ammonium nitrogen, and nitrate nitrogen losses with runoff from plots managed with HT; a 5 to 27% reduction after 63 d; and a 39 to 77% reduction at 2 d. Golf course runoff-to-surface water scenarios were used to calculate estimated environmental concentrations (EECs) of nitrogen and phosphorus in surface water receiving runoff from turf managed with ST or HT core cultivation. Surface water concentrations of phosphorus remained above the U.S. Environmental Protection Agency's water quality criteria to limit eutrophication, with the exception of concentrations associated with HT core cultivation at 2 d. Regardless of management practice (ST or HT) and time between core cultivation and runoff (63 d or 2 d), all EECs of nitrogen were below levels associated with increased algal growth. Understanding nutrient transport with runoff and identifying strategies that reduce off-site transport will increase their effectiveness at intended sites of application and minimize undesirable effects to surrounding surface water resources. Environ. Toxicol. Chem. 2011;30:2473–2480. © 2011 SETAC
Thermodynamic characterization of ternary compounds. I. The case of negligible defect association

The complete thermodynamic specification of the state of a ternary compound requires control of one more experimental parameter than for the case of a binary compound. Two experimental approaches have been used: (a) equilibration with a fixed activity of one of the binary constituents of the ternary compound, and (b) the assumption of a fixed ratio of the two cationic species. It is shown that these two approaches are not equivalent, and that for the latter case, the activities of the binary constituents can vary widely with changes in the equilibrium nonmetal activity. For example, a ternary oxide with a fixed ratio of the two cationic components may be driven out of the single phase region by changes in ambient oxygen pressure, in effect transforming an initial case (b) to case (a), as defined above. BaTiO3 is used as a specific example, and is discussed for the limiting case of negligible coulombic interaction between point defects.
An experimental and theoretical study on the concept of dropwise condensation

Abstract Hydrophobic coatings have been created through self-assembled mono layers (SAMs) of n-octadecyl mercaptan (SAM-1) and stearic acid (SAM-2) on copper alloy (99.9% Cu, 0.1% P) surfaces to enhance steam condensation through dropwise condensation. When compared to complete filmwise condensation, n-octadecyl mercaptan (SAM-1) coated surface increased the condensation heat transfer rate by a factor of 3 for copper alloy surfaces, under vacuum condition (33.86 kPa) and to about eight times when operated under atmospheric condition (101 kPa). A model using the population balance concept is used to derive a theoretical formula to predict the drop-size distribution of small drops which grow mainly by direct condensation. All the important resistances to heat transfer such as the heat conduction through the drop, vapor–liquid interface are considered in developing this model. By knowing the contact angle of the drop made with the condensing surface and the maximum drop radius the sweeping effect of large falling drops could be calculated which is also incorporated into the model. The effect of interfacial heat transfer coefficient on heat transfer rate is also considered in developing the theoretical model. This is combined with the well known size distribution for large drops proposed by Le Fevre and Rose [E.J. Le Ferve, J.W. Rose, A theory of heat transfer by dropwise condensation, in: Proceedings of 3rd International Heat Transfer Conference, vol. 2, Chicago, 1966, pp. 362–375] which grow mainly by coalescence. There has been a satisfactory agreement between our experimental data and the present theoretical model.
Synthesis and properties of Tl0.6V0.5Sr2Ca2Cu3Ox

Abstract Powder of approximate composition Tl0.6V0.5Sr2Ca2Cu3Ox was synthesized in O2 at 970°C from a mixture of oxides of nominal composition Tl2V0.5Sr2Ca2Cu3Ox. The onset Tc was 110 K. Magnetic hysteresis measurements indicated that above ≈ 60 K the irreversibility behavior was superior to that of TlBa2Ca2Cuin3Ox, which has a Tc of ≈ 118 K. The individual grains were up to ≈ 50 μm in length, with aspect ratios
Toxic effects of hexavalent chromium on brook trout (Salvelinus fontinalis) and rainbow trout (Salmo gairdneri)

Abstract Exposing brook trout to various concentrations of chromium [Cr(VI)] for up to 22 months (including reproduction) significantly increased alevin mortality at 0.35 mg Cr l−1 and retarded growth of young brook trout at the lowest concentration tested (0.01 mg Cr l−1). Eight month exposures of rainbow trout significantly increased alevin mortality at 0.34 mg Cr l−1 and also retarded growth at the lowest concentration tested (0.10 mg Cr l−1). Exposures of brook trout lasting 22 months showed, however, that growth was only temporarily affected, and therefore, it was not used as an end point to measure the affects of chromium on either species. Reproduction, and embryo hatchability of brook trout were unaffected at Cr(VI) concentrations that affected survival of newly hatched alevins. The maximum acceptable toxicant concentration (MATC) for brook and rainbow trout exposed to Cr(VI) in water with a hardness of 45 mg l−1 (as CaCO3) and a pH range of 7–8 lies between 0.20 and 0.35 mg Cr l−1. The 96-h lc 50 for brook and rainbow trout was 59 and 69 mg Cr l−1, respectively: therefore, the application factor (MATC/96-h lc 50) for both species lies between 0.003 and 0.006.
Regulation of hepatic vitellogenin synthesis in the little skate (Raja erinacea) : use of a homologous enzyme-linked immunosorbent assay

An enzyme-linked immunosorbent assay (ELISA) was developed to detect vitellogenin in skates. The antibody raised against the yolk protein lipovitellin was shown to recognize a sexspecific, estrogen-inducible 205 kD protein in plasma, previously identified in skate as vitellogenin. The detection limit of the assay was 31.3 ng/ml, similar to that of radioimmunoassays for vitellogenin detection in other species. Using the assay, vitellogenin levels were shown to be highest (241.8 ± 26.5 ug/ml) in the ovarian follicular phase, decreasing approximately 1-2 days before ovulation to a low (173.1 ± 22.9 ug/ml) during the luteal phase. Vitellogenin levels increased again approximately 1-2 days before oviposition to 259.8 ± 38.8 ug/ml. The effects of estrogen and progesterone on hepatic vitellogenin production in normal and hypophysectomized male skates were also investigated. Plasma vitellogenin was not detectable in either intact or hypophysectomised male skates, but increased with estradiol treatment (intact: 48.2 ± 4.9 ug/ml vs. hypophysectomised 252 ± 10.6 ug/ml at day 8). Progesterone treatment significantly (P < .01) attenuated the effect of estrogen on plasma vitellogenin levels in both intact (17 ± 2.1 ug/ml) and hypophysectomized (44.0 ± 9.4 ug/ml) male skates. © 1993 Wiley-Liss, Inc.
Electrochemical Considerations for Determining Absolute Frontier Orbital Energy Levels of Conjugated Polymers for Solar Cell Applications

Narrow bandgap conjugated polymers in combination with fullerene acceptors are under intense investigation in the field of organic photovoltaics (OPVs). The open circuit voltage, and thereby the power conversion efficiency, of the devices is related to the offset of the frontier orbital energy levels of the donor and acceptor components, which are widely determined by cyclic voltammetry. Inconsistencies have appeared in the use of the ferrocenium/ferrocene (Fc + /Fc) redox couple, as well as the values used for the absolute potentials of standard electrodes, which can complicate the comparison of materials properties and determination of structure/property relationships.
Colopexy as a Treatment for Rectal Prolapse in Dogs and Cats: A Retrospective Study of 14 Cases

Colopexy was evaluated as a treatment for recurrent rectal prolapse in eight dogs and six cats. Cases included in the study were from two institutions; the University of Pennsylvania School of Veterinary Medicine and the University of Tennessee College of Veterinary Medicine. Two different colopexy techniques were used: A simple suture technique was used in two cats and four dogs (University of Pennsylvania), and an incisional technique was used in four cats and four dogs (University of Tennessee). Rectal prolapse had not recurred in any of the 14 animals at the time of follow-up. Incisional dehiscence occurred in two animals and in one instance may have been related to the colopexy procedure. Infection at the colopexy site, secondary to suture penetration of the colonic lumen, is a potential complication of this procedure. Colopexy, using either surgical technique described here, was effective in preventing recurrent rectal prolapse.
Solution‐grown polyethylene dendrites

Polyethylene has been crystallized from toluene solution under varying conditions of quenching. The concentration, temperature gradient, pressure, and viscosity has been varied. Depending upon the conditions, different dendrites were found. The dendrites were named in accordance with their appearance: epitaxial dendrites, rightangle dendrites, six-ended dendrites, and hedgehog dendrites. The resulting structures were analyzed with an interference microscope and with a polarizing microscope. On flattening dendrites on the microscope slide, regular structures with a weak birefringence of 0.0026 and an average refractive index of 1.527 ± 0.009 were found. The dendrites have a bundlelike appearance in three dimensions with a strong birefringence (∼0.07). Correlation to single crystal growth from solution and spherulitic growth from the melt has been attempted.
Establishing enterprise communities

One of the most important challenges facing the builders of enterprise software is the reliable implementation of the policies that are supposed to govern the various communities operating within an enterprise. Such policies are widely considered fundamental to enterprise modeling, and their specification were the subject of several recent investigations. But specification of the policy that is to govern a given community is only the first step towards its implementation; the second, and more critical step is to ensure that all members of the community actually conform to the specified policy. The conventional approach to the implementation of a policy is to build it into all members of the community subject to it. But if the community in question is large and heterogeneous, and if its members are dispersed throughout a distributed enterprise, then such "manual" implementation of its policy would be too laborious and error-prone to be practical. Moreover, a policy implemented in this manual manner would be very unstable with respect to the evolution of the system, because it can be violated by a change in the code of any member of community subject to it. It is our thesis that the only reliable way for ensuring that an heterogeneous distributed community of software modules and people conforms to a given policy is for this policy to be strictly enforced. A mechanism for establishing enterprise communities by formally specifying their policies, and by having these policies enforced is the subject of the paper.
Single Crystal Wurtzitic Aluminum Nitride Growth on Silicon Using Supersonic Gas Jets

Highly oriented aluminum nitride (0001) films have been grown on Si(001) and Si (111) substrates at temperatures between 550° C and 775° C with dual supersonic molecular beam sources. Triethylaluminum (TEA;[(C2H5)3Al]) and ammonia (NH3) were used as precursors. Hydrogen, helium, and nitrogen were used as seeding gases for the precursors, providing a wide range of possible kinetic energies for the supersonic beams due to the disparate masses of the seed gases. Growth rates of AIN were found to depend strongly on the substrate orientation and the kinetic energy of the incident precursor; a significant increase in growth rate is seen when seeding in hydrogen or helium as opposed to nitrogen. Growth rates were 2–3 times greater on Si(001) than on Si(111). Structural characterization of the films was done by reflection high energy electron diffraction (RHEED) and x-ray diffraction (XRD). X-ray rocking curve (XRC) full-width half-maxima (FWHM) were seen as small as 2.5°. Rutherford back scattering (RBS) was used to determine the thickness of the films and their chemical composition. Films were shown to be nitrogen rich, deviating from perfect stoichiometry by 10%–20%. Surface analysis was performed by Auger electron spectroscopy (AES).
Internal waves, fossil turbulence, and composite ocean microstructure spectra

Composite vertical shear spectra of Gargett et al. (1981) and composite vertical temperature-gradient spectra of Gregg (1977) are compared with the fossil-turbulence model of Gibson (1980–6). Both the shear and temperature-gradient spectra show high-wavenumber microstructure bumps which are identified by Gargett et al. (1981) and Gregg (1980) as due to turbulence in the fluid at the time of measurement. However, using γ [ges ] 5N as the criterion for turbulence to exist in a stratified fluid, where γ is the rate of strain and N is the Brunt-Vaisala frequency, the largest-scale fluctuations of the microstructure bumps may actually be remnants of previous turbulence persisting in fluid that is no longer turbulent at these scales: such fluctuations are termed fossil vorticity turbulence (a class of internal waves) and fossil temperature turbulence respectively. Both composite spectra exhibit k−1 subranges which are identified by their low amplitudes as subsaturated (two-three)-dimensional internal waves and resulting temperature fine structure by comparison with saturated three-dimensional internal-wave subranges proposed by Gibson (1980):7N2k−1 for the saturated vertical shear spectrum and , also indicating extreme undersampling of the turbulence and mixing.