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.

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.

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.

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.

Diffraction contrast STEM of dislocations: imaging and simulations.

The application of scanning transmission electron microscopy (STEM) to crystalline defect analysis has been extended to dislocations. The present contribution highlights the use of STEM on two oppositely signed sets of near-screw dislocations in hcp α-Ti with 6wt% Al in solid solution. In addition to common systematic row diffraction conditions, other configurations such as zone axis and 3g imaging are explored, and appear to be very useful not only for defect analysis, but for general defect observation. It is demonstrated that conventional TEM rules for diffraction contrast such as g·b and g·R are applicable in STEM. Experimental and computational micrographs of dislocations imaged in the aforementioned modes are presented.

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.

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.

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.

Transmission electron microscopic investigation of a Pd-Ag-In-Sn dental alloy.

With the price volatility of palladium, there has been renewed interest in palladium-silver alloys for metal-ceramic restorations in dentistry. The microstructures of a popular Pd-Ag dental alloy were investigated in the as-cast and simulated porcelain-firing heat-treated conditions, using transmission electron microscopy. In the as-cast condition, the microstructure was strongly influenced by microsegregation, and contained the face-centered cubic Pd solid solution matrix, a eutectic structure with lattice parameters that varied for the two phases, and a face-centered tetragonal (fct) precipitate. After heat treatment, the lattice parameters for the two phases in the eutectic structure were uniform, and discontinuous precipitates with [011](matrix) habit planes and dislocations appeared in the matrix. An unusual nanostructured constituent was found in the fct set of eutectic lamellae in the heat-treated alloys.

Helicobacter pylori and autoimmune neutropenia.

Recent studies have suggested a high prevalence of Helicobacter pylori infection in patients with immune thrombocytopenia. Eradication therapy for H. pylori led to an increase in platelet count in a significant number of patients. No evidence of lymphoproliferative disorder has been reported in any of the patients in these studies. We describe a patient who presented initially with autoimmune neutropenia but was subsequently found to have a mucosa-associated lymphoid tissue (MALT) lymphoma. An impressive recovery of the neutrophil count was noted on H. pylori eradication therapy. To our knowledge this is the first reported case of autoimmune neutropenia associated with H. pylori-induced MALT lymphoma. The relationship between lymphoproliferative disorders and autoimmunity is discussed.

Liposomal daunorubicin (DaunoXome) in combination with cyclophosphamide, vincristine and prednisolone (COP-X) as salvage therapy in poor-prognosis non-Hodgkins lymphoma.

We treated 33 patients with a variant of the standard 3 weekly CHOP regime, replacing doxorubicin with liposomal daunorubicin (DaunoXome, NeXstar Pharmaceuticals) 120 mg/m2 (COP-X). Eighteen subjects had relapsed/refractory aggressive NHL and 15 had indolent NHL/CLL. Median number of courses received was 4 (1-8). Thirty-two patients were evaluable for efficacy and 26 (81%) responded. 88% of patients with aggressive NHL responded; three (18%) patients achieved complete remission (CR), 12 (70%) achieved partial remission (PR), 1 (6%) patient had stable disease (SD) and 1 (6%) patient progressed through treatment. Median duration of response for patients with aggressive NHL was 3 months. The response rate in indolent NHL/CLL was 73%. Four (27%) patients achieved CR, 7 (46%) PR and 4 (27%) SD. At two years post treatment, 55% of the patients with indolent NHL/CLL remain progression-free, although 4 patients have proceeded to consolidation therapy. Twenty-seven out of 28 (96%) patients developed neutropenia of short duration following one or more of their treatments. Twenty-three patients developed an infection at some stage during therapy (all associated with neutropenia) and required hospitalisation. There were two toxic deaths (infection) both of which occurred in patients who were neutropenic before starting COP-X. Platelet toxicity was mild in patients with normal platelet counts at the commencement of therapy. Alopecia and mucositis were mild. No clinical evidence of myocardial failure was observed. We conclude that the substitution of DaunoXome for doxorubicin in the CHOP regimen to form COP-X provides excellent efficacy against non-Hodgkin's lymphoma. Response durations were short but comparable to those reported with other regimens. COP-X was well tolerated with some suggestion of reduced non-haematological toxicity. The regimen should be considered as an alternative to CHOP with potentially less non-haematological toxicity, particularly cardiac; further studies are required to evaluate the regimen in this context.

Effectiveness of ECT combined with risperidone against aggression in schizophrenia.

Aggressive behavior in schizophrenic patients can often be problematic not only for the patients themselves, but for their families and others. This study examined the effect of electroconvulsive therapy (ECT) in combination with risperidone in an open trial in 10 male schizophrenic patients with significant aggressive behaviors. Patients were given bilateral ECT five times a week in combination with risperidone. The mean total number of times of ECT was 6.6 (range 5-9). The aggressive behavior in five of the six patients, who showed positive symptoms, was rapidly ameliorated within 12 days. The ECT/risperidone regimen also eliminated aggressive behavior in four patients showing no positive symptoms within 10 days. These treatment effects lasted for at least 6 months in 9 (of the 10) patients. The results suggest that ECT, combined with risperidone, produce a rapid and effective elimination of aggressive behaviors in schizophrenic patients. In addition, there was a resolution of aggression in four patients with no positive symptoms. This suggests that aggression in some schizophrenic patients develops as a primary symptom of schizophrenia and is not related to other positive symptoms of the disease or the patient's personality traits.

CCNU (lomustine), idarubicin and dexamethasone (CIDEX): an effective oral regimen for the treatment of refractory or relapsed myeloma.

We report the results of a non-randomized pilot study of an oral regimen comprising CCNU (lomustine; 25 or 50 mg/m2 on day 1), idarubicin (4-demethoxydaunorubicin) (10 mg/m2 on days 1-3) and dexamethasone (10 mg b.d. on days 1-4) in patients with relapsed or refractory myeloma. Treatment was given every 28 d for a maximum of six courses. Sixty patients were entered of whom 57 were evaluable. Overall response rate (partial or minor response) was 49% with 30% of patients achieving a partial response (50% tumour reduction). Response rates were higher in patients with untested relapse than in those with refractory disease (overall response rates 56% vs. 31%). The major toxicity was neutropenia and the regimen was otherwise well tolerated. The median survival from entry of all patients was 15 months, with 30% of patients alive at 2 years. This regimen represents a useful addition to available treatment options.

Gamma-vinyl GABA inhibits methamphetamine, heroin, or ethanol-induced increases in nucleus accumbens dopamine.

We examined the acute effect of the irreversible GABA-transaminase inhibitor, gamma-vinyl GABA (GVG, Sabril((R)), Vigabatrin((R))) on increases in nucleus accumbens (NAc) dopamine (DA) following acute administration of methamphetamine, heroin, or ethanol. Methamphetamine (2.5 mg/kg) produced a dose-dependent increase (2, 700%) in NAc DA. GVG preadministration (300 or 600 mg/kg), however, inhibited this response by approximately 39 and 61%, respectively. The lower dose of methamphetamine (1.25 mg/kg), increased DA by 1, 700%. This response was inhibited to a similar extent (44%) regardless of the GVG dose preadministered (300 or 600 mg/kg). In addition, heroin-induced increases in NAc DA (0.5 mg/kg, 170%) were inhibited or completely abolished by GVG (150 or 300 mg/kg, 65 and 100%, respectively). Finally, at half the dose necessary for heroin, GVG (150 mg/kg) also completely abolished ethanol-induced increases in NAc DA following a 0.25 g/kg challenge dose (140%). Taken with our previous findings using nicotine or cocaine as the challenge drug, these results indicate that GVG attenuates increases in NAc DA by a mechanism common to many drugs of abuse. However, it appears unlikely that an acute dose of GVG can completely inhibit increases in NAc DA following challenges with a drug whose mechanism of action is mediated primarily through the DA reuptake site.

Analysis of the pattern of QM expression during mouse development.

QM, a novel gene that was originally identified as a putative tumor suppressor gene, has since been cloned from species encompassing members of the plant, animal, and fungal kingdoms. Sequence comparison indicates that QM has been highly conserved throughout eukaryotic evolution. QM is a member of a multigene family in both mouse and man, is expressed in a broad range of tissues, and is downregulated during adipocyte differentiation. Jif-1, a chicken homolog of QM, has been reported to interact with the protooncogene c-Jun, and to inhibit transactivation of AP-1 regulated promoters in vitro. Furthermore, disruption of the yeast QM homolog is lethal. Although these studies suggest that the QM gene product plays an important role within the normal cell, the precise role of QM has remained elusive. In this study, a thorough analysis of the pattern of QM expression during mouse development was undertaken, using the techniques of whole mount in situ hybridization and whole mount immunohistochemistry, in combination with conventional immunohistochemical analysis of tissue sections. QM is expressed in numerous embryonic tissues, and is differentially expressed throughout the embryo. The cytoplasmic localization of QM is consistent with its reported association with ribosomes, and inconsistent with its previously hypothesized function as a direct modulator of the nuclear protooncogene c-Jun. QM is expressed in the developing epidermis, and is particularly strong within developing limbs. Analysis of embryos of various stages of gestation indicate that QM is downregulated in the surface ectoderm of the embryo as development proceeds. QM protein is not detectable within either nucleated or enucleated red blood cell precursors. QM is strongly expressed within chondrocytes within the transition zone of developing limb cartilage, as well as within differentiated keratinocytes of the suprabasal regions of the epidermis. Furthermore, within both cartilage and skin, there is an inverse relationship between QM expression and proliferative capacity. This pattern of QM expression suggests that this novel gene product may be involved in processes such as posttranslational protein processing which are essential for differentiation of specific tissues during embryogenesis.

Epic as an effective, low toxicity salvage therapy for patients with poor risk lymphoma prior to beam high dose chemotherapy and peripheral blood progenitor cell transplantation.

We treated 33 patients with relapsed or refractory non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD) with a combination of etoposide, prednisolone, ifosfamide and carboplatin (EPIC). After a median of two courses (range 1-5) complete response was achieved in 7 (22%) patients and partial response in 12 (37%) patients, an overall response rate of 59%. The regimen was well tolerated with myelosuppression being the most common toxicity. There were no toxic deaths. 25 (78%) patients were able to proceed to high dose therapy (BEAM) with peripheral blood progenitor cell transplantation either immediately post EPIC or following further salvage therapy. Most patients mobilised peripheral blood progenitor cells well and 24 out of 25 patients subsequently undergoing autologous transplantation had rapid regeneration of counts. EPIC is an effective salvage therapy in the majority of patients with relapsed or refractory lymphoma and does not appear to be toxic to stem cells. Although severe, myelosuppression is of short duration and the generally low toxicity enables patients to proceed to successful peripheral blood stem cell harvest and transplantation.

Rapid analysis of low levels of indolyl-3-acryloylglycine in human urine by high-performance liquid chromatography.

There have been several reports of increased levels of excretion of indolyl-3-acryloylglycine (IAcrGly) in human urine in a number of disease states. However, the metabolic source of this compound is still not clear and there is the possibility of more than one mechanism for IAcrGly production. There was therefore a need for a rapid, low limit of quantitation assay for IAcrGly to enable further study in this area. In the assay described here, these analytical requirements were addressed by utilising a solid-phase extraction method for sample clean-up, reversed-phase LC with an on-column focusing method of sample introduction and UV absorbance detection at 326 nm. The limit of quantitation of this method was 26.2 ng ml(-1). It was also noted that IAcrGly undergoes isomerisation when exposed to light and that this process is reversible.

Prearraignment forensic evaluations: toward a new policy.

Prearraignment forensic evaluations are forensic psychiatric evaluations performed on a suspect soon after his or her arrest. In the guise of ethics, the committee members who originated this code have imposed apparently personal and political views on all members of respective professional organizations in order to circumvent rulings of the judiciary, including the U.S. Supreme Court. The prohibition against prearraignment evaluations represents a misapplication of physician-as-healer-based medical ethics--in which the core principle is the physician's beneficence to the patient--to the forensic arena, where no physician-patient relationship exists and healing is not the purpose. The ethical code prohibiting prearraignment evaluations reflects misguided paternalism and political bias, as well as being in direct conflict with current law. Whether or not prearraignment evaluations should be permitted is primarily a Fifth and Sixth Constitutional Amendment issue more than a traditional medical-ethical one. Ethics and the law, when both are examined carefully, suggest prearraignment evaluations are proper when performed responsibly.