Low defect densities in molecular beam epitaxial GaAs achieved by isoelectronic In doping

We have studied the effects of adding small amounts of In (0.2–1.2%) to GaAs grown by molecular beam epitaxy. The density of four electron traps decreases in concentration by an order of magnitude, and the peak intensities of prominent emissions in the excitonic spectra are reduced with increase in In content. Based on the higher surface migration rate of In, compared to Ga, at the growth temperatures it is apparent that the traps and the excitonic transitions are related to point defects. This agrees with earlier observations by F. Briones and D. M. Collins [J. Electron. Mater. 11, 847 (1982)] and B. J. Skromme, S. S. Bose, B. Lee, T. S. Low, T. R. Lepkowski, R‐Y. DeJule, G. E. Stillman, and J. C. M. Hwang [J. Appl. Phys. 58, 4702 (1985)].Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69821/2/APPLAB-49-8-470-1.pd

Hybrid type-I InAs/GaAs and type-II GaSb/GaAs quantum dot structure with enhanced photoluminescence

We investigate the photoluminescence (PL) properties of a hybrid type-I InAs/GaAs and type-II GaSb/GaAs quantum dot (QD) structure grown in a GaAs matrix by molecular beam epitaxy. This hybrid QD structure exhibits more intense PL with a broader spectral range, compared with control samples that contain only InAs or GaSb QDs. This enhanced PL performance is attributed to additional electron and hole injection from the type-I InAs QDs into the adjacent type-II GaSb QDs. We confirm this mechanism using time-resolved and power-dependent PL. These hybrid QD structures show potential for high efficiency QD solar cell applications

Thermal dosimetry characteristics of deep regional heating of non-muscle invasive bladder cancer.

PURPOSE: The aim of this paper is to report thermal dosimetry characteristics of external deep regional pelvic hyperthermia combined with intravesical mitomycin C (MMC) for treating bladder cancer following transurethral resection of bladder tumour, and to use thermal data to evaluate reliability of delivering the prescribed hyperthermia dose to bladder tissue. MATERIALS AND METHODS: A total of 14 patients were treated with MMC and deep regional hyperthermia (BSD-2000, Sigma Ellipse or Sigma 60). The hyperthermia objective was 42° ± 2 °C to bladder tissue for ≥40 min per treatment. Temperatures were monitored with thermistor probes and recorded values were used to calculate thermal dose and evaluate treatment. Anatomical characteristics were examined for possible correlations with heating. RESULTS: Combined with BSD-2000 standard treatment planning and patient feedback, real-time temperature monitoring allowed thermal steering of heat sufficient to attain the prescribed thermal dose to bladder tissue within patient tolerance in 91.6% of treatments. Mean treatment time for bladder tissue \u3e40 °C was 61.9 ± 11.4 min and mean thermal dose was 21.3 ± 16.5 CEM43. Average thermal doses obtained in normal tissues were 1.6 ± 1.2 CEM43 for the rectum and 0.8 ± 1.3 CEM43 in superficial normal tissues. No significant correlation was seen between patient anatomical characteristics and thermal dose achieved in bladder tissue. CONCLUSIONS: This study demonstrates that a hyperthermia prescription of 42° ± 2 °C for 40-60 min can be delivered safely to bladder tissue with external radiofrequency phased array applicators for a typical range of patient sizes. Using the available thermometry and treatment planning, the BSD-2000 hyperthermia system was shown to be an effective method of focusing heat regionally around the bladder with good patient tolerance

GaSb Thermophotovoltaic Cells Grown on GaAs by Molecular Beam Epitaxy Using Interfacial Misfit Arrays

There exists a long-term need for foreign substrates on which to grow GaSb-based optoelectronic devices. We address this need by using interfacial misfit arrays to grow GaSb-based thermophotovoltaic cells directly on GaAs (001) substrates and demonstrate promising performance. We compare these cells to control devices grown on GaSb substrates to assess device properties and material quality. The room temperature dark current densities show similar characteristics for both cells on GaAs and on GaSb. Under solar simulation the cells on GaAs exhibit an open-circuit voltage of 0.121 V and a short-circuit current density of 15.5 mA/cm2. In addition, the cells on GaAs substrates maintain 10% difference in spectral response to those of the control cells over a large range of wavelengths. While the cells on GaSb substrates in general offer better performance than the cells on GaAs substrates, the cost-savings and scalability offered by GaAs substrates could potentially outweigh the reduction in performance. By further optimizing GaSb buffer growth on GaAs substrates, Sb-based compound semiconductors grown on GaAs substrates with similar performance to devices grown directly on GaSb substrates could be realized

Design and Validation of Patient-Centered Communication Tools (PaCT) to Measure Students\u27 Communication Skills

Objective. To develop a comprehensive instrument specific to student pharmacist-patient communication skills, and to determine face, content, construct, concurrent, and predictive validity and reliability of the instrument. Methods. A multi-step approach was used to create and validate an instrument, including the use of external experts for face and content validity, students for construct validity, comparisons to other rubrics for concurrent validity, comparisons to other coursework for predictive validity, and extensive reliability and inter-rater reliability testing with trained faculty assessors. Results. Patient-centered Communication Tools (PaCT) achieved face and content validity and performed well with multiple correlation tests with significant findings for reliability testing and when compared to an alternate rubric. Conclusion. PaCT is a useful instrument for assessing student pharmacist communication skills with patients

Vancomycin Dosing Practices among Critical Care Pharmacists: A Survey of Society of Critical Care Medicine Pharmacists

Introduction: Critically ill patients and their pharmacokinetics present complexities often not considered by consensus guidelines from the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, and the Society of Infectious Diseases Pharmacists. Prior surveys have suggested discordance between certain guideline recommendations and reported infectious disease pharmacist practice. Vancomycin dosing practices, including institutional considerations, have not previously been well described in the critically ill patient population. Objectives: To evaluate critical care pharmacists\u27 self-reported vancomycin practices in comparison to the 2009 guideline recommendations and other best practices identified by the study investigators. Methods: An online survey developed by the Research and Scholarship Committee of the Clinical Pharmacy and Pharmacology (CPP) Section of the Society of Critical Care Medicine (SCCM) was sent to pharmacist members of the SCCM CPP Section practicing in adult intensive care units in the spring of 2017. This survey queried pharmacists\u27 self-reported practices regarding vancomycin dosing and monitoring in critically ill adults. Results: Three-hundred and sixty-four responses were received for an estimated response rate of 26%. Critical care pharmacists self-reported largely following the 2009 vancomycin dosing and monitoring guidelines. The largest deviations in guideline recommendation compliance involve consistent use of a loading dose, dosing weight in obese patients, and quality improvement efforts related to systematically monitoring vancomycin-associated nephrotoxicity. Variation exists regarding pharmacist protocols and other practices of vancomycin use in critically ill patients. Conclusion: Among critical care pharmacists, reported vancomycin practices are largely consistent with the 2009 guideline recommendations. Variations in vancomycin dosing and monitoring protocols are identified, and rationale for guideline non-adherence with loading doses elucidated

Fifteen new risk loci for coronary artery disease highlight arterial-wall-specific mechanisms

Coronary artery disease (CAD) is a leading cause of morbidity and mortality worldwide. Although 58 genomic regions have been associated with CAD thus far, most of the heritability is unexplained, indicating that additional susceptibility loci await identification. An efficient discovery strategy may be larger-scale evaluation of promising associations suggested by genome-wide association studies (GWAS). Hence, we genotyped 56,309 participants using a targeted gene array derived from earlier GWAS results and performed meta-analysis of results with 194,427 participants previously genotyped, totaling 88,192 CAD cases and 162,544 controls. We identified 25 new SNP-CAD associations (P < 5 × 10(-8), in fixed-effects meta-analysis) from 15 genomic regions, including SNPs in or near genes involved in cellular adhesion, leukocyte migration and atherosclerosis (PECAM1, rs1867624), coagulation and inflammation (PROCR, rs867186 (p.Ser219Gly)) and vascular smooth muscle cell differentiation (LMOD1, rs2820315). Correlation of these regions with cell-type-specific gene expression and plasma protein levels sheds light on potential disease mechanisms