Insight into hydrogen production through molecular simulation of an electrode-ionomer electrolyte system.

In this work, we examine metal electrode-ionomer electrolyte systems at high voltage (negative surface charge) and at high pH to assess factors that influence hydrogen production efficiency. We simulate the hydrogen evolution electrode interface investigated experimentally in the work of Bates et al. [J. Phys. Chem. C 119, 5467 (2015)] using a combination of first principles calculations and classical molecular dynamics. With this detailed molecular information, we explore the hypotheses posed in the work of Bates et al. In particular, we examine the response of the system to increased bias voltage and oxide coverage in terms of the potential profile, changes in solvation and species concentrations away from the electrode, surface concentrations, and orientation of water at reactive surface sites. We discuss this response in the context of hydrogen production.

On the origin of extraordinary cyclic strengthening of the austenitic stainless steel Sanicro 25 during fatigue at 700°C.

The origin of the extraordinary strengthening of the highly-alloyed austenitic stainless steel Sanicro 25 during cyclic loading at 700°C was investigated by use of advanced scanning transmission electron microscopy (STEM). Along with substantial change of dislocation structure, nucleation of two distinct populations of nanoparticles was revealed. Fully coherent Cu-rich nanoparticles were observed homogeneously dispersed with high density along with nanometer-sized incoherent NbC carbides precipitating on dislocations during cyclic loading. Probe-corrected HAADF STEM imaging was used to characterize the atomic structure of nanoparticles. Compositional analysis was conducted using both EELS and high spatial resolution EDS. High temperature exposure induced precipitation of a high density of coherent Cu-rich nanoparticles while strain-induced nucleation of incoherent NbC nanoparticles leads to retardation of dislocation movement. The pinning effects and associated obstacles to dislocation motion prevent recovery and formation of the localized low-energy cellular structures. As a consequence, the alloy exhibits remarkable cyclic hardening at elevated temperature.

Metamorphic In(0.20)Ga(0.80)As p-i-n photodetectors grown on GaAs substrates for near infrared applications.

The growth and performance of top-illuminated metamorphic In(0.20)Ga(0.80)As p-i-n photodetectors grown on GaAs substrates using a step-graded In(x)Ga(1-x)As buffer is reported. The p-i-n photodetectors display a low room-temperature reverse bias dark current density of ~1.4×10(-7) A/cm(2) at -2 V. Responsivity and specific detectivity values of 0.72 A/W, 2.3×10(12) cm·Hz(1/2)/W and 0.69 A/W, 2.2×10(12) cm·Hz(1/2)/W are achieved for Yb:YAG (1030 nm) and Nd:YAG (1064 nm) laser wavelengths at -2 V, respectively. A high theoretical bandwidth-responsivity product of 0.21 GHz·A/W was estimated at 1064 nm. Device performance metrics for these GaAs substrate-based detectors compare favorably with those based on InP technology due to the close tuning of the detector bandgap to the target wavelengths, despite the presence of a residual threading dislocation density. This work demonstrates the great potential for high performance metamorphic near-infrared InGaAs detectors with optimally tuned bandgaps, which can be grown on GaAs substrates, for a wide variety of applications.

Effect of gallium focused ion beam milling on preparation of aluminium thin foils.

Focussed ion beam milling has greatly extended the utility of the atom probe and transmission electron microscope because it enables sample preparation with a level of dimensional control never before possible. Using focussed ion beam it is possible to extract the samples from desired and very specific locations. The artefacts associated with this sample preparation method must also be fully understood. In this work, issues specifically relevant to the focussed ion beam milling of aluminium alloys are presented. After using the focussed ion beam as a sample preparation technique it is evident that gallium will concentrate in three areas of the sample: on the surface, on grain boundaries and at interphase boundaries. This work also shows that low-energy Ar ion nanomilling is potentially quite effective for removing gallium implantation layers and gallium from the internal surfaces of aluminium thin foils.

Effects of naloxone on schizophrenia: reduction in hallucinations in a subpopulation of subjects.

Endogenous opiate-like peptides (endorphins) are putative neuroregulators located throughout the mammalian brainstem. There is some evidence for their role in pain, stress, and affect. We report that the opiate antagonist, naloxone, alters some schizophrenic symptoms. In a double-blind, cross-over study, naloxone produced decreases in auditory hallucinations in some schizophrenic patients. This finding supports the hypothesis that the endorphins may play a roll in modulating hallucinations in a highly selected subgroup of chronically hallucinating schizophrenic patients.

Dynamical scattering image simulations for two-phase γ-γ' microstructures: A theoretical model.

We introduce an extension of the Darwin-Howie-Whelan (DHW) equations for the case of coherent L12 precipitates in an FCC matrix. The equations are similar in form to the conventional DHW equations and are sufficiently general to account for the different translational variants of the precipitate phase as well as for the displacement fields of arbitrary lattice defects. An approximate scheme to perform fast and accurate image simulations using a pre-computed list of scattering matrices is also introduced. Finally, the results of diffraction pattern and image simulations are shown for two synthetic microstructures for a Ni-Al alloy generated using phase field simulations. The dynamical scattering equations reveal that the precipitate phase superlattice beams can propagate through the disordered matrix, but they are fully decoupled from the fundamental waves.

HRTEM of dislocation cores and thin-foil effects in metals and intermetallic compounds.

Examples of the observation and analysis of dislocation cores and dislocation fine structure in metals and intermetallics using high resolution transmission electron microscopy are discussed. Specific examples include the 60 degrees dislocations in aluminum, a011 edge dislocations in NiAl, and screw dislocations in Ni3Al. The effect of the thin TEM foils on the structure and imaging of these dislocations is discussed in light of embedded atom method calculations for several configurations and coupled with image simulations. Some generalizations based on these calculations are discussed. These analyses enables determination of the spreading or decomposition of the edge component of the cores, both in and out of the glide plane, which can have significant implications for the modeling of macroscopic behavior.

Phase transformation strengthening of high-temperature superalloys.

Decades of research has been focused on improving the high-temperature properties of nickel-based superalloys, an essential class of materials used in the hot section of jet turbine engines, allowing increased engine efficiency and reduced CO2 emissions. Here we introduce a new 'phase-transformation strengthening' mechanism that resists high-temperature creep deformation in nickel-based superalloys, where specific alloying elements inhibit the deleterious deformation mode of nanotwinning at temperatures above 700 °C. Ultra-high-resolution structure and composition analysis via scanning transmission electron microscopy, combined with density functional theory calculations, reveals that a superalloy with higher concentrations of the elements titanium, tantalum and niobium encourage a shear-induced solid-state transformation from the γ' to η phase along stacking faults in γ' precipitates, which would normally be the precursors of deformation twins. This nanoscale η phase creates a low-energy structure that inhibits thickening of stacking faults into twins, leading to significant improvement in creep properties.

Imaging and characterization of fine gamma' precipitates in a commercial nickel-base superalloy.

Empirical datasets of volume fractions and size distributions of small gamma' precipitates from "real" multi-component engineering nickel-based superalloys are vital to calibrate and validate the computer models which predict high sensitivities of mechanical properties to size and volume fraction of these fine gamma precipitates, and in order to accelerate microstructure and alloy development. Consequently, we investigated a number of imaging techniques available in a Tecnai F-20 FEG/TEM and selected the technique which best enabled rapid and extensive acquisition of these datasets using the engineering alloy, René 88'DT. The EFTEM technique was found to be the most appropriate method for imaging fine gamma' precipitates while further investigation showed that the Cr-M-edge, in comparison with other ionization-edges provided the best images based largely on contrast-to-noise ratio. Imaging of the Cr-M-edge elemental maps were further improved by investigating the effects of microscope parameters, imaging filter parameters and analysis of the experimental electron energy loss spectra obtained from this alloy. In addition, a novel technique to determine the volume fraction of the fine gamma' precipitates without the need to determine the absolute thickness of the TEM foil is proposed.

Behavioral precipitants to civil commitment.

The authors examined retrospectively the prehospitalization behavior of 66 voluntary and involuntary psychiatric patients to determine precipitating factors in each person's hospitalization. Involuntary patients had engaged in dangerous acts directed against others more frequently than had voluntary patients. However, very little significant harm was caused by members of either group.

Behavioral changes following surgery for obesity.

The authors interviewed 69 subjects who had had jejuno-ileal bypass surgery for obesity to determine the relationship between weight loss and eating behavior after surgery. All patients had been extremely overweight; at an average of 37 months after surgery, their mean weight was reduced by 39%. There were four significant postoperative changes: voluntary restriction of food intake, "normalization" of eating patterns, resistance to eating during intense emotion, and far less dysphoria during postsurgical weight loss than during previous weight loss efforts. The authors therefore suggest that factors other than impaired intestinal absorption may account for some portion of postsurgical weight loss.

Protecting third parties: a decade after Tarasoff.

The authors discuss current public policy concerning the treatment of potentially violent psychiatric patients and outline some legal and ethical precedents of the current policy. Therapeutic interventions before and after the Tarasoff decision are compared. The authors make specific recommendations for clinicians, who they believe tend to interpret laws too restrictively. They suggest that courts need to rethink current liability standards so that legal decisions can be more clinically informed. Finally, they believe that legislative interventions which specify that warning the potential victim and notifying the police absolve psychotherapists from liability may lead to reflexive rather than reflective management of violent patients.

Mutism: review, differential diagnosis, and report of 22 cases.

Mutism is a common manifestation of both psychiatric and neurologic illness. Psychiatric disturbances associated with mutism include schizophrenia, affective disorders, conversion reactions, dissociative states, and dementias. Neurologic disorders producing mutism involve the basal ganglia, frontal lobes, or limbic system structures. In psychiatric and neurologic conditions, mutism is often associated with other signs of catatonia. The authors review the literature on mutism, including psychiatric, neurologic, toxic-metabolic, and drug-induced causes. Methods to discriminate among the many causes of mutism in the clinical setting are discussed, and 22 new cases of mutism are reported to emphasize the wide differential diagnosis.

Mental patients' knowledge of in-hospital rights.

The authors questioned 52 recently admitted patients about formally receiving information regarding patients' rights and about their knowledge of that information. Of the 13 day hospital patients, 12 recalled being given the information, but only 20 of 39 inpatients recalled receiving the information. Most patients, irrespective of their diagnosis or legal status, knew their rights. Surprisingly, comparison with a group of patients who did not receive information on their rights revealed no relationship between receiving this information and knowledge of patients' rights. On the basis of these and other findings, the authors discuss some difficulties with presentation of patients' rights and offer recommendations.

Electroconvulsive therapy in Massachusetts.

A study of the use of electroconvulsive therapy in Massachusetts shows that between 1974 and 1980 ECT use decreased significantly in both public- and private-sector hospitals. This decline was particularly pronounced in public-sector hospitals. The average age of ECT-treated patients rose during the period; women received ECT more often than men; and bilateral ECT remained in more frequent use. Though ECT was most frequently prescribed for major depression, about 20% of those receiving it were diagnosed as having a dysthymic disorder. State regulation and advances in psychiatric treatment may partially explain the decrease in ECT use.

A brief test for measuring malingering in schizophrenic individuals.

The M Test, a brief test for measuring malingering of schizophrenic illness, contains true-false items describing actual symptoms of schizophrenia, bizarre attitudes and beliefs, and fake symptoms. Normal subjects rarely endorsed any of the items. The responses of genuinely ill schizophrenic inpatients were compared with those of normal subjects who had been asked to fake malingering after being educated about the symptoms of schizophrenia and forewarned about the purpose of the test. The test significantly discriminated between genuinely ill patients and malingerers. The test correctly identified 87.3% of the schizophrenic subjects and 78.2% of the malingering normal subjects.

Serum level monitoring of thiothixene in schizophrenia: acute single-dose levels at fixed doses.

After establishing a strong correlation between steady-state thiothixene levels and levels drawn 2.5 hours after a 20-mg test dose, the authors examined the correlation between clinical improvement and serum levels drawn 2.5 hours after a single 20-mg test dose of thiothixene. For 30 male schizophrenic inpatients, improvement on the Brief Psychiatric Rating Scale was significantly correlated with the single test-dose levels. Serum levels were also positively correlated with age, which may explain the tendency of elderly patients to require lower neuroleptic doses and to exhibit a higher incidence of side effects. The results suggest that acute single-dose levels may be useful in predicting clinical response to thiothixene.

Short-term civil commitment and the violent patient.

To explore the specificity of criteria for civil commitment for dangerousness, the authors examined the relationship between civil commitment for dangerousness to others under the California Civil Commitment Statute (the Lanterman-Petris-Short Act) and violent acts and behavioral ratings made immediately after commitment. Using a prospective design they evaluated 84 subjects. The ratings of violent acts for subjects considered dangerous to others were no different than those of a nondangerous control group. The subjects considered dangerous to others, however, differed on several subscales of the Brief Psychiatric Rating Scale. The authors discuss the implications of these results for civil commitment proceedings.

Psychotic patients' understanding of informed consent.

Courts have found psychiatric patients to have the qualified right to refuse treatment. Particularly problematic is whether newly admitted psychiatric patients can comprehend information and give informed consent. The authors examined the ability of voluntary and involuntary psychotic patients to understand information about antipsychotic medication, related this assessment to psychopathology, and evaluated factors involved in hypothetical acceptance or refusal of treatment. Although most patients stated they had understood informed consent material, objective ratings did not support this. Impaired understanding was significantly associated with thought disturbance but did not affect hypothetical acceptance or refusal of antipsychotics. Legal status was not a significant factor.

Legal liability with psychotropic drug use: extrapyramidal syndromes and tardive dyskinesia.

The use of medication has become essential to the practice of modern psychiatry. Despite the enormous benefits associated with the administration of psychotropics, these drugs also carry the risk of significant adverse reactions. The legal implications of side effects of antipsychotic agents are explored. The particular focus is on the potentially serious liability confronting the psychiatrist whose patient develops delayed neuromuscular complications. Whenever neuroleptic medication is used, it is crucial for all psychiatrists to be cognizant of the need to obtain voluntary informed consent in the context of clinically appropriate treatment.