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Few studies have considered how signal detection parameters evolve during acquisition periods. We addressed this gap by training mice with differential prior experience in a conditional discrimination, auditory signal detection task. Naïve mice, mice given separate experience with each of the later correct choice options (Correct Choice Response Transfer, CCRT), and mice experienced in conditional discriminations (Conditional Discrimination Transfer, CDT) were trained to detect the presence or absence of a tone in white noise. We analyzed data assuming a two-period model of acquisition: a pre-solution and solution period (Heinemann EG (1983) in The Presolution period and the detection of statistical associations. In: Quantitative analyses of behavior: discrimination processes, vol. 4, pp. 21–36). Ballinger. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.536.1978andrep=rep1andtype=pdf). The pre-solution period was characterized by a selective sampling of biased response strategies until adoption of a conditional responding strategy in the solution period. Correspondingly, discriminability remained low until the solution period; criterion took excursions reflecting response–strategy sampling. Prior experience affected the length and composition of the pre-solution period. Whereas CCRT and CDT mice had shorter pre-solution periods than naïve mice, CDT and Naïve mice developed substantial criterion biases and acquired asymptotic discriminability faster than CCRT mice. To explain these data, we propose a learning model in which mice selectively sample and test different response-strategies and corresponding task structures until they exit the pre-solution period. Upon exit, mice adopt the conditional responding strategy and task structure, with action values updated via inference and generalization from the other task structures. Simulations of representative mouse data illustrate the viability of this model. [ABSTRACT FROM AUTHOR]

Engineering strong metal–support interactions (SMSI) is an effective strategy for tuning structures and performances of supported metal catalysts but induces poor exposure of active sites. Here, we demonstrate a strong metal–support interaction via a reverse route (SMSIR) by starting from the final morphology of SMSI (fully-encapsulated core–shell structure) to obtain the intermediate state with desirable exposure of metal sites. Using core–shell nanoparticles (NPs) as a building block, the Pd–FeOx NPs are transformed into a porous yolk–shell structure along with the formation of SMSIR upon treatment under a reductive atmosphere. The final structure, denoted as Pd–Fe3O4–H, exhibits excellent catalytic performance in semi-hydrogenation of acetylene with 100% conversion and 85.1% selectivity to ethylene at 80 °C. Detailed electron microscopic and spectroscopic experiments coupled with computational modeling demonstrate that the compelling performance stems from the SMSIR, favoring the formation of surface hydrogen on Pd instead of hydride. Strong metal–support interactions (SMSI) are effective in tuning the structures and catalytic performances of catalysts but limited by the poor exposure of active sites. Here, the authors develop a strategy to engineer SMSI via a reverse route, which is in favor of metal site exposure while embracing the SMSI. [ABSTRACT FROM AUTHOR]

Nature can efficiently recognize specific ions by exerting second-sphere interactions onto well-folded protein scaffolds. However, a considerable challenge remains to artificially manipulate such affinity, while being cost-effective in managing immense amounts of water samples. Here, we propose an effective approach to regulate uranyl capture performance by creating bio-inspired nano-traps, illustrated by constructing chelating moieties into porous frameworks, where the binding motif’s coordinative interaction towards uranyl is enhanced by introducing an assistant group, reminiscent of biological systems. Representatively, the porous framework bearing 2-aminobenzamidoxime is exceptional in sequestering high uranium concentrations with sufficient capacities (530 mg g−1) and trace quantities, including uranium in real seawater (4.36 mg g−1, triple the benchmark). Using a combination of spectroscopic, crystallographic, and theory calculation studies, it is revealed that the amino substituent assists in lowering the charge on uranyl in the complex and serves as a hydrogen bond acceptor, boosting the overall uranyl affinity of amidoxime. [ABSTRACT FROM AUTHOR]

Rationale Prolonged use of nicotine appears to enhance incentive salience, a motivational-cognitive process that transforms an otherwise neutral stimulus into a Bwanted stimulus. It has been suggested that nicotinic enhancement of incentive salience contributes to the potential of relapse in individuals with tobacco addiction. However, there are two main limitations of prior research that caution this claim: (a) the use of passive experimentally delivered nicotine and (b) the use of sign-tracking as an index of incentive salience, without acknowledging the competing nature of goal- and sign-tracking responses. Objectives To determine whether nicotinic enhancement of incentive salience attributed to non-nicotinic stimuli occurs when rats self-administer nicotine, and whether it is facilitated by a prior history of nicotine self-administration. Methods Twenty-three male rats were trained daily, for 24 days, on a nicotine self-administration (SA) paradigm in the morning, and on a four-conditioned-stimuli Pavlovian conditioned approach (4-CS PCA) task in the afternoon. Self-administration was followed by extinction and cue reinstatement. A subcutaneous nicotine challenge was performed during the last 7 days of the study. Results Nicotine self-administration selectively enhanced sign-tracking in the 4-CS PCA. Upon extinction, sign-tracking quickly declined to control levels. Experimenter-administered nicotine enhanced sign-tracking similarly regardless of nicotine history. Conclusions The results suggest that nicotinic enhancement of incentive salience is transient, and a previous history of nicotine use does not cause further sensitization. Taken together, these results suggest that nicotine enhances incentive salience, particularly-- and perhaps exclusively--while onboard. [ABSTRACT FROM AUTHOR]

Amidoxime-functionalized polymeric adsorbents are the current state-of-the-art materials for collecting uranium (U) from seawater. However, marine tests show that vanadium (V) is preferentially extracted over U and many other cations. Herein, we report a complementary and comprehensive investigation integrating ab initio simulations with thermochemical titrations and XAFS spectroscopy to understand the unusually strong and selective binding of V by polyamidoximes. While the open-chain amidoxime functionalities do not bind V, the cyclic imide-dioxime group of the adsorbent forms a peculiar non-oxido V5+ complex, exhibiting the highest stability constant value ever observed for the V5+ species. XAFS analysis of adsorbents following deployment in environmental seawater confirms V binding solely by the imide-dioximes. Our fundamental findings offer not only guidance for future optimization of selectivity in amidoxime-based sorbent materials, but may also afford insight to understanding the extensive accumulation of V in some marine organisms. [ABSTRACT FROM AUTHOR]

This paper describes the Kidney Disease Quality of Life (KDQOL) Instrument (dialysis version), a self-report measure that includes a 36-item health survey as the generic core, supplemented with multi-item scales targeted at particular concerns of individuals with kidney disease and on dialysis (symptom/problems, effects of kidney disease on daily life, burden of kidney disease, cognitive function, work status, sexual function, quality of social interaction, sleep). Also included were multi-item measures of social support, dialysis staff encouragement and patient satisfaction, and a single-item overall rating of health. The KDQOL was administered to 165 individuals with kidney disease (52% female; 48% male; 47% White; 27% African-American; 11% Hispanic; 8% Asian; 4% Native American; and 3% other ethnicities), sampled from nine different outpatient dialysis centres located in Southern California, the Northwest, and the Midwest. The average age of the sample was 53 years (range from 22 to 87), and 10% were 75 years or older. Internal consistency reliability estimates for the 19 multi-item scales exceeded 0.75 for every measure except one. The mean scores for individuals in this sample on the 36-item health scales were lower than the general population by one-quarter (emotional well-being) to a full standard deviation (physical function, role limitations due to physical health, general health), but similar to scores for dialysis patients in other studies. Correlations of the KDQOL scales with number of hospital days in the last 6 months were statistically significant (p < 0.05) for 14 of the 19 scales and number of medications currently being taken for nine of the scales. Results of this study provide support for the reliability and validity of the KDQOL. [ABSTRACT FROM AUTHOR]

Functional materials for energy conversion and storage exhibit strong coupling between electrochemistry and mechanics. For example, ceramics developed as electrodes for both solid oxide fuel cells and batteries exhibit cyclic volumetric expansion upon reversible ion transport. Such chemomechanical coupling is typically far from thermodynamic equilibrium, and thus is challenging to quantify experimentally and computationally. In situ measurements and atomistic simulations are under rapid development to explore how this coupling can be used to potentially improve both device performance and durability. Here, we review the commonalities of coupling between electrochemical and mechanical states in fuel cell and battery materials, illustrating with specific cases the progress in materials processing, in situ characterization, and computational modeling and simulation. We also highlight outstanding questions and opportunities in these applications - both to better understand the limiting mechanisms within the materials and to significantly advance the durability and predictability of device performance required for renewable energy conversion and storage. [ABSTRACT FROM AUTHOR]

This paper reviews the fundamental concepts and the terminology of wetting. In particular, it focuses on high temperature wetting phenomena of primary interest to materials scientists. We have chosen to split this review into two sections: one related to macroscopic (continuum) definitions and the other to a microscopic (or atomistic) approach, where the role of chemistry and structure of interfaces and free surfaces on wetting phenomena are addressed. A great deal of attention has been placed on thermodynamics. This allows clarification of many important features, including the state of equilibrium between phases, the kinetics of equilibration, triple lines, hysteresis, adsorption (segregation) and the concept of complexions, intergranular films, prewetting, bulk phase transitions versus 'interface transitions', liquid versus solid wetting, and wetting versus dewetting. [ABSTRACT FROM AUTHOR]

Existing methods to rapidly compute interface-energy minimizing shapes with anisotropy are collected and clarified, and new methods are introduced. A description of freely available, platform-independent software for the computation and display of equilibrium geometries is provided. The software relies on a new computational method to rapidly find equilibrium geometries. It also features a graphical user interface and includes the 32 crystallographic point groups to simplify inputting interfacial energies and their associated orientations. When a particle is completely enclosed within a single interface (isolated), the software computes and provides visualization for Wulff shapes. When a particle is enclosed by two interfaces, such as a particle at a grain boundary, the software minimizes their collective interfacial energy; if one of the interfaces is planar, the computation reproduces the Winterbottom construction. When both interfaces are deformable, the software provides a new tool for calculating the particle shape and the distortions of boundaries that are attached to it, even for highly anisotropic interfaces. The properties of particles bounded by two deformable interfaces are discussed, and applications of the software are illustrated. In some cases, the software can be used as a method to infer values of relative interfacial energies from a microscopic observation. [ABSTRACT FROM AUTHOR]

Background. Axillary ultrasound (AUS) with needle biopsy is used to detect metastasis in patients with invasive breast cancers. Our hypothesis is that preoperative AUS significantly reduces sentinel node biopsy (SLNB) use in patients with invasive breast tumors >2 cm upon clinical examination. Methods. A single-institution database of patients with breast cancer and AUS was reviewed. Patients with incomplete records, clinical tumor <2 cm, or postoperative AUS were excluded. A control cohort of non-AUS patients with clinical T2 (cT2) or greater disease was identified. Clinicopathologic data were collected. Simple Kappa coefficient and chi-square statistical analyses were performed. Results. AUS was performed in 153 patients vs. 370 controls. Of AUS patients, 112 (73.2%) had cT2 disease vs. 272 (73.5%) controls. Median AUS patient age was 53.7 (range, 22.8-85.8) years vs. 53.8 (range, 26.7-91.6) years; median pathologic tumor was 3.8 (range, 1.0-20.0) cm in AUS patients vs. 2.5 (range, 0.1-11.0) cm. Among AUS patients, 78% had needle biopsy; 85 of 120 (70.8%) were positive. Sixty-eight patients had SLNB: 33 after negative AUS and 35 after negative needle biopsy. Twenty-three SLNB (37.3%) were positive; 15 of 33 after negative AUS and 8 of 35 after a negative needle biopsy. Axillary dissection was performed in 102 of 153 vs. 225 of 370 controls. Sensitivity and specificity of AUS was 86.2% and 40.5%. Sensitivity of AUS plus needle biopsy was 89.3% with 100% specificity. Neoadjuvant chemotherapy was given to 49.7% of AUS patients. AUS reduced costs by more than $4,000 per patient. Conclusions. AUS reduces SLNB use and affects treatment in patients with cT2 or greater breast cancer. Routine AUS should be considered in this population. [ABSTRACT FROM AUTHOR]

We demonstrate the formation of non-close-packed binary colloidal structures through a novel layer-by-layer directed self-assembly methodology. In this approach we deposit colloidal suspensions of particle concentration and controlled electrostatic potential onto a planar template with a periodic array of features that is able to trap the particles, nucleating ordered domains with a template-defined symmetry and periodicity that permits subsequent, sequential deposition to produce an ordered heterostructure. Specifically, a silicon template with a hole pattern formed by interference lithography that corresponds to [100] symmetry of a cubic system has been used. At low particle concentrations, and using a Debye length that is on the order of the particle diameter, ordered domains in which polystyrene (PS) particles occupy every other site in the template are formed. The remaining sites on the 2D template are then filled by identically sized silica particles using vertical deposition. This process is repeated to produce a second layer of the same structure. Upon removing the PS particles, a two-layer non-close-packed structure that is a half-unit-cell precursor to the diamond cubic structure is obtained. To our knowledge this is the first demonstration of colloidal self-assembly to obtain a non-close-packed multilayer structure. Challenges that remain in applying the approach to create extended three-dimensional structures are discussed. [ABSTRACT FROM AUTHOR]

HER2 overexpression imparts a metastatic advantage in breast cancer. We have shown that HER2 signaling in breast cancer cells induces adjacent endothelial cell (EC) retraction, disrupting endothelial integrity. Because endothelial integrity is dependent on the adherens junctions, we postulated that the mechanism of tumor cell-induced EC retraction involves dissociation of catenin proteins from vascular endothelial (VE) cadherin. In this study, we report a loss of VE-cadherin in tumor-associated EC. We also tested for a change of catenin dissociation from VE-cadherin by manipulating HER2 signaling in tumor cells. We tested confluent monolayers of human EC for downregulation of VE cadherin and dissociation of catenins from VE cadherin after exposure to breast cancer cells or conditioned media. Using immunoprecipitation, we quantitated the remaining complexed catenins to VE-cadherin in tumor-associated EC after different treatments to manipulate HER2 signaling. Treatment of EC with conditioned media from MCF-7 cells expressing HER2 induced a loss of VE-cadherin expression, and time-dependent dissociation of catenins from VE cadherin. Catenin dissociation from VE-cadherin was enhanced by Heregulin β1 ( P < .05) stimulation and decreased by trastuzumab ( P < .05) blockade of HER2 signaling in cancer cells. An increase in EC phosphoSrc (Tyr 416) was seen by 8 hours. Our data suggest that HER2 induction of EC retraction involves both down-regulation of VE-cadherin and dissociation of catenins. HER2 signaling appears to regulate this potential metastatic mechanism. Further, Src phosphorylation suggests that this pathway may be involved in this mechanism. [ABSTRACT FROM AUTHOR]

The representation of the degradation of the monoterpenes, α- and β-pinene, in version 3.1 of the Master Chemical Mechanism (MCM v3.1) has been evaluated, using environmental chamber data from the Statewide Air Pollution Research Center (SAPRC) at the University of California. As part of this evaluation, a representation of the reactions of the monoterpenes with O(3P) has also been included, these reactions being significant under chamber conditions but generally insignificant under atmospheric conditions. The results demonstrate that MCM v3.1 provides a consistent description of the photo-oxidation of α-pinene/NO X mixtures for a range of initial VOC/NO X , but with the formation rate of ozone and decay rate of α-pinene generally being overestimated. Sensitivity of the system to parameter uncertainties and mechanistic variations proposed in the literature are described. The collective implementation of a number of refinements allows the simulations to be brought into good agreement with the experimental observations for the complete series of experiments, with each of the refinements being consistent with reported parameter uncertainty ranges or mechanistic adjustments. The system is particularly sensitive to the magnitudes of sources and sinks of free radicals. The impacts of several other reported mechanistic variations which potentially influence the first generation product distribution and the ozone formation chain length of the initial oxidation step are also described and assessed. MCM v3.1 is shown to provide a reasonable, but less consistent, description of photo-oxidation of β-pinene/NO X mixtures. The simulated magnitudes of the ozone formation rates and β-pinene removal rates are broadly comparable with the experimental observations, but the mechanism tends towards overestimation of ozone formation at low VOC/NO X and underestimation at high VOC/NO X . Implementation of a number of mechanistic variations reported in the literature does not allow the associated simulations to be brought into good agreement with the observations for the entire VOC/NO X range. The system is particularly sensitive to changes which influence the formation of HCHO (and resultant radical production upon its photolysis), and the impacts of the tested mechanistic variations are usually dominated by this effect. As a result of this work, gaps and uncertainties in the kinetic, mechanistic and chamber database for the monoterpenes are identified and discussed. [ABSTRACT FROM AUTHOR]

When an interaction has been detected among the chemicals in a mixture, it may be of interest to predict the interaction threshold. A method is presented for estimation of an interaction threshold along a mixture ray which allows differences in the shapes of the dose-response curves of the individual components (e.g., mixtures of full and partial agonists with differing response maxima). A point estimate and confidence interval for the interaction threshold may be estimated. The methods are illustrated with data from a study of a mixture of 18 polyhalogenated aromatic hydrocarbons (PHAHs) in rats exposed by oral gavage for four consecutive days. Serum total thyroxine (T4) was the response variable. Previous analysis of these data demonstrated a dose-dependent interaction among the 18 chemicals in the mixture, with additivity suggested in the lower portion of the dose-response curve and synergy (greater than additive response) in the higher portion of the dose-response curve. The present work builds on this analysis by construction of an interaction threshold model along the mixture ray. This interaction threshold model has two components: an implicit additivity region and an explicit region that describes the departure from additivity; the interaction threshold is the boundary between the two regions. Estimation of the interaction threshold within the observed experimental region suggested evidence of additivity in the low dose region. Total doses of the mixture that exceed the upper limit of the confidence interval on the interaction threshold were associated with a greater-than-additive interaction. [ABSTRACT FROM AUTHOR]

The conditions for grain boundary (GB) structural transitions are determined from a diffuse interface model that incorporates structural disorder and crystallographic orientation. A graphical construction and numerical calculations illustrate the existence of a first-order GB order–disorder transition below the bulk melting point. When thermodynamic conditions permit their existence, disordered GB structures tend to be stable at higher temperatures and are perfectly wet by liquid at the melting point, while ordered grain boundaries are meta-stable against preferential melting. We calculate GB phase diagrams which are analogous to those for liquid–vapor phase transitions. [ABSTRACT FROM AUTHOR]

The representation of alkene degradation in version 3 of the Master Chemical Mechanism (MCM v3) has been evaluated, using environmental chamber data on the photo-oxidation of ethene, propene, 1-butene and 1-hexene in the presence of NOx, from up to five chambers at the Statewide Air Pollution Research Center (SAPRC) at the University of California. As part of this evaluation, it was necessary to include a representation of the reactions of the alkenes with O(3P), which are significant under chamber conditions but generally insignificant under atmospheric conditions. The simulations for the ethene and propene systems, in particular, were found to be sensitive to the branching ratios assigned to molecular and free radical forming pathways of the O(3P) reactions, with the extent of radical formation required for proper fitting of the model to the chamber data being substantially lower than the reported consensus. With this constraint, the MCM v3 mechanisms for ethene and propene generally performed well. The sensitivity of the simulations to the parameters applied to a series of other radical sources and sink reactions (radical formation from the alkene ozonolysis reactions and product carbonyl photolysis; radical removal from the reaction of OH with NO2 and β-hydroxynitrate formation) were also considered, and the implications of these results are discussed. Evaluation of the MCM v3 1-butene and 1-hexene degradation mechanisms, using a more limited dataset from only one chamber, was found to be inconclusive. The results of sensitivity studies demonstrate that it is impossible to reconcile the simulated and observed formation of ozone in these systems for ranges of parameter values which can currently be justified on the basis of the literature. As a result of this work, gaps and uncertainties in the kinetic, mechanistic and chamber database are identified and discussed, in relation to both tropospheric chemistry and chemistry important under chamber conditions which may compromise the evaluation procedure, and recommendations are made for future experimental studies. Throughout the study, the performance of the MCM v3 chemistry was also simultaneously compared with that of the corresponding chemistry in the SAPRC-99 mechanism, which was developed and optimized in conjunction with the chamber datasets. [ABSTRACT FROM AUTHOR]

A statistical approach for modeling fracture in brittle materials is presented. In particular, a microstructural-based finite element code called OOF is used in conjunction with a stochastic representation of failure that relies on the Weibull law. The OOF code, which maps materials microstructures onto finite element meshes, enables to calculate the local stress states; these stresses are used along with the statistical criterion for brittle fracture in order to determine microcrack formation and propagation. Computer simulations are performed on several microstructures of different materials types, e.g., laminates, particulate composites and polycrystals. The damage accumulation due to microcracking is characterized by the stereological measure of failed material and is investigated in order to assess the effect of microstructural features on the failure mechanism. Moreover, the approach allows to analyze the influence of the characteristic parameters for brittle materials on damage evolution. [ABSTRACT FROM AUTHOR]

Previous numerical methods that calculate equilibrium particle shape to study thermodynamic and kinetic processes depend on interfacial (surface) free energy functions γ( $$\skew7\hat{n}$$) that have cubic symmetry and thus produce Wulff shapes W of cubic symmetry. This work introduces a construction yielding the minimal surface energy density γconvex( W) that can be determined for any W. Each γ( $$\skew7\hat{n}$$) that belongs to the equivalence class γ( W) bounded by γconvex( W) can be used in an energy-minimizing calculation that depends only on W. For practical numerical calculations, this work gives two methods taking directional distance from specified orientation minima as a parameter to produce analytic forms of γ( $$\skew7\hat{n}$$) giving W as the equilibrium shape for (an otherwise unconstrained) fixed volume. Included are several two- and three-dimensional examples that demonstrate the application and utility of the model γ( $$\skew7\hat{n}$$) functions. [ABSTRACT FROM AUTHOR]

In the analysis of mixtures of drugs/chemicals it is often of interest to test for the presence of interaction. If the hypothesis of no interaction (additivity) is not rejected, then the analyst may reasonably claim additivity if and only if the study is powered to a desired (e.g., biologically meaningful) level. The objective of this article is to address the sample size and power issues related to testing the hypothesis of additivity at specified mixture points. The study of disinfectant by-products (DBPs) found in drinking water, described in earlier literature, is used to illustrate the procedures for estimating power and sample sizes for detecting interactions at specified mixtures. The four trihalomethanes used in the study are bromodichloromethane (BDCM), chlorodibromomethane (CDBM), chloroform (CHCl3), and bromoform (CHBr3) [ABSTRACT FROM AUTHOR]

This article presents and illustrates an approach to designing and analyzing studies involving mixtures/combinations of drugs or chemicals along fixed-ratio rays of the drugs or chemicals for generalized linear models. When interest can be restricted to a specific ray, we consider fixed-ratio ray designs to reduce the amount of experimental effort. When a ray design is used, we have shown that the hypothesis of additivity can be rejected when higher order polynomial terms are required in the total dose-response model. Thus, it is important that we have precise parameter estimates for these higher order polynomial terms in the linear predictor. We have developed methodology for finding a D s -optimal design based on this subset of the terms in the linear predictor. [ABSTRACT FROM AUTHOR]

An important environmental and regulatory issue is the protection of human health from potential adverse effects of cumulative exposure to multiple chemicals. Earlier literature suggested restricting inference to specific fixed-ratio rays of interest. Based on appropriate definitions of additivity, single chemical data are used to predict the relationship among the chemicals under the zero-interaction case. Parametric comparisons between the additivity model and the model fit along the fixed-ratio ray(s) are used to detect departure from additivity. Collection of data along reduced fixed-ratio rays, where subsets of chemicals of interest are removed from the mixture and the remaining compounds are at the same relative ratios as considered in the full ray, allow researchers to make inference about the effect of the removed chemicals. Methods for fitting simultaneous confidence bands about the difference between the best fitting model and the model predicted under additivity are developed to identify regions along the rays where significant interactions occur. This general approach is termed the “single chemicals required” (SCR) method of analysis. A second approach, termed “single chemicals not required” (SCNR) method of analysis, is based on underlying assumptions about the parameterization of the response surface. Under general assumptions, polynomial terms for models fit along fixed-ratio rays are associated with interaction terms. Consideration is given to the case where only data along the mixture rays are available. Tests of hypotheses, which consider interactions due to subsets of chemicals, are also developed. [ABSTRACT FROM AUTHOR]

A case of a ruptured middle colic artery is reported. The diagnosis was initially overlooked and eventually made by selective arteriography. Aneurysms of visceral arteries are rare and rupture of them even more infrequent. Awareness of this potentially fatal and treatable entity should enable early detection by selective visceral arteriography. The roles of embolization and surgery in the management of visceral aneurysms are discussed. [ABSTRACT FROM AUTHOR]

A study of the high-temperature oxidation and NaSO-induced hot corrosion of some nickel-base superalloys has been accomplished by using ESCA to determine the surface composition of the oxidized or corroded samples. Oxidation was carried out at 900 or 1000°C in slowly flowing O for samples of B-1900, NASA-TRW VIA, 713C, and IN-738. Oxidation times ranged from 0.5 to 100 hr. Hot corrosion of B-1900 was induced by applying a coating of NaSO to preoxidized samples, then heating to 900° C in slowly flowing O. Corrosion times ranged from 5 min to 29 hr. For oxidized samples, the predominant type of scale formed by each superalloy was readily determined, and a marked surface enrichment of Ti was found in each case. For corroded samples, the transfer of significant amounts of material from the oxide layer to the surface of the salt layer was observed to occur long before the onset of rapidly accelerating weight gain. Some marked changes in surface composition were observed to coincide with the beginning of accelerating corrosion, the most striking of which were a tenfold decrease in the sulfur to sodium ratio and an increase in the Cr(VI) to Cr(III) ratio. [ABSTRACT FROM AUTHOR]

In in vitro testing, no pharmacologic synergism has been found for the combination of cisplatin and etoposide in P388 leukemia in contrast to the demonstration of therapeutic synergism in the same model. No pharmacologic synergism has been found for the same combination in the treatment of four small-cell lung-cancer cell lines, although clinical results obtained using this combination in small-cell lung cancer and other cancers suggest a therapeutic advantage. The popular concept of synergy, implying a therapeutic advantage, is different from the pharmacologic meaning, which generally implies that less drug is required in a combination for an equal effect. Therapeutic advantage may be obtained regardless of whether drugs are synergistic in the pharmacologic sense in the treatment of a tumor. To gain a more comprehensive insight into concepts of drug interaction, it is important to recognize that the type of drug interaction seen is dependent on the drug doses used and may vary with the treatment of different cell lines. All of these factors complicate the use of the word synergism, or any associated term, in a categorical manner to describe the effects of combinations of antineoplastic drugs. [ABSTRACT FROM AUTHOR]

A case of fatal dilated cardiomyopathy induced by esorubicin (ESO) at a total dose of 740 mg/m2, given in 27 doses over 650 days, is reported. The sudden onset, rapid clinical deterioration, and fatal outcome are detailed. The outcome was not predicted by serial rest ejection fractions or clinical signs. The data from animal studies, phase 1 and phase 2 clinical testing, are reviewed, demonstrating the almost complete absence of reports of ESO-induced cardiotoxicity. Studies reviewing ejection fractions and myocardial biopsy scores show that ESO can be cardiotoxic and may produce fatal dilated cardiomyopathy. [ABSTRACT FROM AUTHOR]

Patients' perceptions of the extent to which their health care needs have been met may affect compliance with prescribed health behaviors and related health outcomes. The authors examined the relationships of "patient request fulfillment" to patient compliance, glycemic control, and several other health care outcomes in 51 adult outpatients with insulin-dependent diabetes mellitus. On average, patients retrospectively cited 4.5 long-term requests, of which over three-fourths were fulfilled. Fulfillment of these requests was significantly associated with patient satisfaction, perceived health status, fewer insulin reactions, and greater insulin injection time reliability (p less than 0.05), but not with several other measures of compliance. Higher patient request fulfillment at single visits was correlated, as hypothesized, with subsequent reduction in glycosylated hemoglobin, but this association was not statistically significant. These results suggest that patient request fulfillment is associated with several aspects of health behavior and health status in adults with insulin-dependent diabetes. Further studies are needed to confirm these observations and determine whether strategies to enhance patient request fulfillment can enhance health care outcomes. [ABSTRACT FROM AUTHOR]

Photoluminescence (PL) measurements were carried out on commercial ZnO varistor samples that were electrically stressed and/or annealed at different temperatures. Changes in the intensity of green and yellow luminescence centers were studied as a function of annealing treatment. It was found that the ZnO luminescence (green and yellow) decrease with increase in annealing temperature, reach a minimum at 700°C, and increase again beyond 800°C. Furthermore, these green and yellow luminescence bands observed in the PL spectra are quenched in the ZnO varistor samples, compared to pure ZnO. In an electrically stressed ZnO varistor sample, the luminescence intensity was found to be higher compared to the as-sintered varistor sample. Annealing of the stressed varistor sample resulted in a decrease of the luminescence intensity. These PL observations are consistent with previous deep level transient spectroscopy and doppler positron annihilation spectroscopy results. All of the experimental results are consistent with the ion migration model of degradation and can be explained using a grain boundary defect model. [ABSTRACT FROM AUTHOR]

Polycrystalline films of CdZnTe ( x = 0-0.4) and CdMnTe ( x = 0-0.25) were grown by MBE and MOCVD, respectively, on CdS/SnO/glass substrates to investigate their feasibility for solar cell applications. The compositional uniformity and interface quality of the films were analyzed by x-ray diffraction, surface photovoltage, and Auger depth profile measurements to establish a correlation between growth conditions and lattice constant, atomic concentration, and bandgap of the ternary films. MBE-grown polycrystalline CdZnTe films showed a linear dependence between Zn/(Cd + Zn) beam flux ratio, Zn concentration in the film, and the bandgap. Polycrystalline CdZnTe films grown at 300° C showed good compositional uniformity in contrast to compositionally non-uniform CdMnTe films grown by MOCVD in the temperature range of 420-450° C. The MBE-grown CdZnTe interface also showed significantly less interdiffusion compared to the MOCVD-grown CdMnTe/CdS interface, where preferential exchange between Cd from the CdS layer and Mn from the CdMnTe film was observed. The compositional uniformity of MOCVD-grown polycrystalline CdMnTe films grown on CdS/SnO/glass substrates was found to be a strong function of the growth conditions as well as the Mn source. [ABSTRACT FROM AUTHOR]

A role for eosinophils in the immune reaction has not been yet established. Considering that these leukocytes accumulate in lymphoid organs under glucocorticoid stimulation, we explored the possibility that they participate in the depression of immune reactions induced by these hormones and that they degranulate to exert this action. In this context, we investigated the dose effect of three estrogens on the number and degranulation of spleen red pulp eosinophils and on the percentage of spleen cross sectional area comprising white pulp. Estradiol-17β or 4(OH)estradiol-17β increased red pulp eosinophils at low doses; 2(OH)estradiol-17β increased them at a very high dose. The three estrogens degranulated the spleen eosinophils and decreased the lymphocyte containing spleen white pulp. We propose that the decrease in white pulp is a response mediated by agents released from degranulating eosinophils under the action of estrogen. Consequently, both estrogen-induced eosinophil degranulation and estrogen-induced increase in red pulp eosinophil numbers are conditions contributing to a decrease in white pulp volume. All above evidence supports the hypothesis that eosinophils are involved in immunoregulation by diminishing the number of lymphocytes contained in lymphoid organs. [ABSTRACT FROM AUTHOR]

Whole fetal human pancreases of 12-22 weeks gestation, showed histological growth and differentiation in vitro over 3 weeks. At glucose concentrations of 1-4 g/l, there was no difference in insulin secretion into culture medium over 1 h. There was no stimulation of insulin release by D-glyceraldehyde, thus defective glucose-stimulated insulin release was probably not due to impairment of an early step in glycolysis. In the presence of 0.5 mmol/l dibutyryl cyclic AMP, insulin secretion was enhanced (0.188±0.030 versus 0.100±0.012 mU·mg tissue·h, p<0.001) independently of glucose concentrations. It thus appears that impairment of glucose-stimulated insulin release was unlikely to be due to insufficient intracellular cyclic AMP. Insulin release increased in response to tolbutamide and theophylline. Insulin secretion was stimulated in the presence of a fivefold increase in amino acid concentration (0.118±0.018 versus 0.031±0.008 mU·mg tissue ·h, p<0.001). There was a fourfold increase in basal insulin secretion from islets previously grown in high concentration of amino acids compared with standard culture medium, (0.284±0.052 versus 0.067±0.011 mU·mg tissue·h, p<0.001), emphasizing the important role of amino acids as substrates for B cell metabolism and development. [ABSTRACT FROM AUTHOR]

Human fibroblast interferon, obtained by chromatography on concanavalin A-agarose, was stable for at least a month in 30-50 per cent ethylene glycol at 4°, −20°, and −70° C. The succinct point of the present finding is that human fibroblast interferon may be stabilized by ethylene glycol alone without the addition of bovine serum albumin and 'back-contamination' of the interferon preparation. [ABSTRACT FROM AUTHOR]

Single 17-day foetal mouse pancreases, cultured for 15 days in RPMI 1640 or DME containing either 1 or 4 g/1 glucose, were grafted under the kidney capsule of syngeneic mice made diabetic with Streptozotocin. Islets cultured in media containing 1 g/l glucose secreted less insulin in vitro than those grown in media containing 4 g/l glucose. After transplantation, the blood glucose levels of diabetic mice grafted with islets grown in media containing 1 g/l glucose decreased to normal limits, whereas mice grafted with islets grown in media with 4 g/l glucose never became normoglycaemic. Histologically, grafts of tissue from high glucose cultures were smaller and had less well organized Islet tissue than grafts from tissue maintained in physiological glucose concentrations. Islets cultured in DME secreted more insulin in vitro than those cultured in RPMI 1640, but the type of culture medium had no significant effect on subsequent graft function. These data support the concept that chronic exposure of foetal islets to high glucose concentrations may be deleterious to their subsequent function as grafts despite the fact that they secrete more insulin in vitro. [ABSTRACT FROM AUTHOR]

In this multicenter, randomized, double-blind study the activity of polyI:polyCU administered with zidovudine was evaluated in the treatment of HIV infection. Thirty-six HIV-positive, pre-AIDS individuals (100-500 CD4 cells/mm) who had had at least six months of zidovudine therapy received polyI:polyCU (400 or 700 mg) or placebo twice weekly with zidovudine. PolyI:polyCU subjects with baseline CD4 counts≥300/mm showed a trend towards reduced CD4 loss versus placebo recipients. PolyI:polyCU subjects were more likely to exhibit positive delayed-type hypersensitivity responses than placebo recipients. Placebo subjects crossing over to polyI:polyCU therapy demonstrated improved CD4 and delayed-type hypersensitivity responses. PolyI: polyCU subjects with baseline CD4 counts≥300/mm were less likely to develop AIDS than similar placebo subjects. PolyI:polyCU therapy of HIV-positive subjects restored or stabilized immune function as indexed by delayed-type hypersensitivity reactivity and, in individuals with CD4 counts>300/mm, abrogated CD4 loss and reduced disease progression. PolyI:polyCU was generally well-tolerated in this zidovudine-treated population. No subject discontinued therapy due to an adverse reaction or aberrant laboratory parameter. [ABSTRACT FROM AUTHOR]

Recent progress in variational methods helps to provide general principles for microstructural evolution. Especially when several processes are interacting, such general principles are useful to formulate dynamical equations and to specify rules for evolution processes. Variational methods provide new insight and apply even under conditions of nonlinearity, nondifferentiability, and extreme anisotropy. Central to them is the concept of gradient flow with respect to an inner product. This article shows, through examples, that both well-known kinetic equations and new triple junctions motions fit in this context. [ABSTRACT FROM AUTHOR]

The article comments on a study by Alvin Chua, Nicole Benedek and coauthors on the computational technique for predicting grain boundaries interface structures which was published in the earlier issue of the journal. As stated the technique merges ab initio calculations with genetic algorithm and thereby simplifies the process of predicting grain boundaries interface structures. It also provides suitable solutions of the atomic structures that were difficult to imagine earlier.

The notion of science as a stratified system is clearly manifested in the markedly uneven distribution of productivity, rewards, resources, and recognition. Although previous studies have shown that institutional environments for conducting research differ significantly between national science systems, disciplines, and subfields, it remains to be shown whether any systematic variations and patterns in inequalities exist among researchers in different national and domain specific settings. This study investigates the positioning of citation elites as opposed to ‘ordinary’ researchers by way of examining three dimensions of concentration (accumulation of publications and citations, specialisation, and institutional concentration) in biology, economics and physics in Denmark and the UK. Across all three dimensions, we put Richard Whitley’s bipartite theory to the test, suggesting a nexus between the intellectual structure of a discipline and the configuration of its elite. The study draws on a dataset of researchers who published most of their publications in either physics, biology, or economics over the 1980–2018 period and with at least one publication in 2017–2018 while affiliated to either a British or a Danish university. We find higher degrees of concentration in the UK compared to Denmark, and that physics and biology respectively display the greatest and lowest degree of concentration. Similar patterns in disciplinary differences are observed in both countries, suggesting that concentration patterns are largely rooted in disciplinary cultures and merely amplified by the national context. [ABSTRACT FROM AUTHOR]