GaAs Solar Cells Grown Directly on V-Groove Si Substrates.

The direct epitaxial growth of high-quality III-V semiconductors on Si is a challenging materials science problem with a number of applications in optoelectronic devices, such as solar cells and on-chip lasers. We report the reduction of dislocation density in GaAs solar cells grown directly on nanopatterned V-groove Si substrates by metal-organic vapor-phase epitaxy. Starting from a template of GaP on V-groove Si, we achieved a low threading dislocation density (TDD) of 3 × 10 cm in the GaAs by performing thermal cycle annealing of the GaAs followed by growth of InGaAs dislocation filter layers.

Pulsed Laser Deposition of Epitaxial SrTiO/SrAlO Templates as a Water-Soluble Sacrificial Layer for GaAs Growth and Lift-Off.

Despite the record-high efficiency of GaAs solar cells, their terrestrial application is limited due to both the particularly high costs related to the required single-crystal substrates and epitaxial growth. A water-soluble lift-off layer could reduce costs by avoiding the need for toxic and dangerous etchants, substrate repolishing, and expensive process steps. SrAlO (SAO) is a water-soluble cubic oxide, and SrTiO (STO) is a perovskite oxide, where ≈ 4 × ≈ (2√2) .

Solution Cathode Glow Discharge Coupled to Atmospheric Pressure Chemical Ionization for Elemental Detection of S and P in Organic Compounds.

We report a post-plasma chemical ionization approach to evaluate solution cathode glow discharge (SCGD) for S and P elemental analysis. Here, the SCGD serves as a reactor to produce chemical vapors for S and P from organic compounds containing these elements, while a corona discharge operated in negative mode is used to ionize the products. The approach creates long-lived ions in atmospheric pressure, enabling direct investigation of chemical vapor products via mass spectrometric and ion mobility separations.

Mechanism of Insoluble Aggregate Formation in a Reconstituted Solution of Spray-Dried Protein Powder.

Background: Spray-drying is considered a promising alternative drying method to lyophilization (freeze-drying) for therapeutic proteins. Particle counts in reconstituted solutions of dried solid dosage forms of biologic drug products are closely monitored to ensure product quality. We found that high levels of particles formed after reconstitution of protein powders that had been spray-dried under suboptimal conditions.

T-cell responses induced by ChAdOx1 nCoV-19 (AZD1222) vaccine to wild-type severe acute respiratory syndrome coronavirus 2 among people with and without HIV in South Africa.

Objectives: This study aimed to investigate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T-cell responses 14 days after single-dose ChAdOx1 nCoV-19 (AZD1222) vaccination in black Africans with and without HIV in South Africa, as well as determine the effect of AZD1222 vaccination on cell-mediated immune responses in people with HIV (PWH) with prior SARS-CoV-2 infection.

Methods: A total of 70 HIV-uninfected people and 104 PWH were prospectively enrolled in the multicentre, randomized, double-blinded, placebo-controlled, phase Ib/IIa trial (COV005). Peripheral blood mononuclear cells (PBMCs) were collected from trial participants 14 days after receipt of first dose of study treatment (placebo or AZD1222 vaccine).

A performance comparison between GaInP-on-Si and GaAs-on-Si 3-terminal tandem solar cells.

The pursuit of ever-higher solar cell efficiencies has focused heavily on multijunction technologies. In tandem cells, subcells are typically either contacted via two terminals (2T) or four terminals (4T). Simulations show that the less-common three-terminal (3T) design may be comparable to 4T tandem cells in its compatibility with a range of materials, operating conditions, and methods for subcell integration, yet the 3T design circumvents shading losses of the 4T intermediate conductive layers.

High-Resolution Elemental Mass Spectrometry Using LC-ICP-Nanospray-Orbitrap for Simultaneous and Species-Independent Quantitation of Fluorinated and Chlorinated Compounds.

Simultaneous elemental detection of F and Cl offers quantitation of fluorinated and chlorinated compounds and their transformation products without compound-specific standards. Despite wide-ranging applications, this capability has been hindered by fundamental and technical shortcomings of current inductively coupled plasma (ICP)-MS methods in ion formation and isobaric interference elimination. These hurdles are alleviated here via a chemical ionization method.

Consideration of the Intricacies Inherent in Molecular Beam Epitaxy of the NaCl/GaAs System.

The high cost of substrates for III-V growth can be cost limiting for technologies that require large semiconductor areas. Thus, being able to separate device layers and reuse the original substrate is highly desirable, but existing techniques to lift a film from a substrate have substantial drawbacks. This work discusses some of the complexities with the growth of a water-soluble, alkali halide salt thin film between a III-V substrate and overlayer.

Sensory features in autism: Findings from a large population-based surveillance system.

Sensory features (i.e., atypical responses to sensory stimuli) are included in the current diagnostic criteria for autism spectrum disorder.

Surveillance of the rabies-related lyssavirus, Mokola in non-volant small mammals in South Africa.

The reservoir host of Mokola virus (MOKV), a rabies-related lyssavirus species endemic to Africa, remains unknown. Only sporadic cases of MOKV have been reported since its first discovery in the late 1960s, which subsequently gave rise to various reservoir host hypotheses. One particular hypothesis focusing on non-volant small mammals (e.

The impact of the wake maintenance zone on attentional capacity, physiological drowsiness, and subjective task demands during sleep deprivation.

We aimed to investigate the impact of the Wake Maintenance Zone (WMZ) on measures of drowsiness, attention, and subjective performance under rested and sleep deprived conditions. We studied 23 healthy young adults (18 males; mean age = 25.41 ± 5.

Synaptic processes and immune-related pathways implicated in Tourette syndrome.

Tourette syndrome (TS) is a neuropsychiatric disorder of complex genetic architecture involving multiple interacting genes. Here, we sought to elucidate the pathways that underlie the neurobiology of the disorder through genome-wide analysis. We analyzed genome-wide genotypic data of 3581 individuals with TS and 7682 ancestry-matched controls and investigated associations of TS with sets of genes that are expressed in particular cell types and operate in specific neuronal and glial functions.

Perturbation-induced high-frequency pulsing of nano-ESI with facile ion selection at atmospheric pressure.

Nano-ESI is a commonly used ionization technique with continually expanding analytical advantages. Here, we report a facile way for high-frequency (500-3800 Hz) pulsing of nano-ESI, providing a high flux of mobility-selected ions. The pulsing is accomplished using a relatively low-voltage modulation (80 V peak-to-peak) of an electrode placed <1 cm downstream of a nano-ESI emitter biased to a constant potential.

The impact of structured sleep schedules prior to an in-laboratory study: Individual differences in sleep and circadian timing.

Introduction: Many sleep and circadian studies require participants to adhere to structured sleep-wake schedules designed to stabilize sleep outcomes and circadian phase prior to in-laboratory testing. The effectiveness of this approach has not been rigorously evaluated, however. We therefore investigated the differences between participants' unstructured and structured sleep over a three-week interval.

Estimated Minimum Life Span of the Jezero Fluvial Delta (Mars).

The paleo-lake floor at the edge of the Jezero delta has been selected as the NASA 2020 rover landing site. In this article, we demonstrate the sequences of lake filling and delta formation and constrain the minimum life span of the Jezero paleo-lake from sedimentological and hydrological analyses. Two main phases of delta evolution can be recognized by utilizing imagery provided by the High Resolution Imaging Science Experiment (NASA Mars Reconnaissance Orbiter) and High Resolution Stereo Camera (ESA Mars Express): (1) basin infilling before the breaching of the Jezero rim and (2) the delta formation itself.

Sustained fluvial deposition recorded in Mars' Noachian stratigraphic record.

Orbital observation has revealed a rich record of fluvial landforms on Mars, with much of this record dating 3.6-3.0 Ga.

A Taxonomy for Three-Terminal Tandem Solar Cells.

Tandem and multijunction solar cells offer the only demonstrated path to terrestrial 1-sun solar cell efficiency over 30%. Three-terminal tandem (3TT) solar cells can overcome some of the limitations of two-terminal and four-terminal tandem solar cell designs. However, the coupled nature of the cells adds a degree of complexity to the devices themselves and the ways that their performance can be measured and reported.

Pulsed Nano-ESI: Application in Ion Mobility-MS and Insights into Spray Dynamics.

We have previously shown that pulsed nano-ESI offers direct ion introduction into an AP-IM cell in the absence of conventional gates and desolvation. Here, we further characterize this ion injection method and utilize it to gain insights into nano-ESI pulsed spray dynamics. We demonstrate that a pulsed nano-ESI operated at 20 Hz with ion generation pulses of 170-510 μs offers reproducible ion arrival times (0.

A multiple lines of evidence approach for identifying geologic heterogeneities in conceptual site models for performance assessments.

Model-based decision making is commonly used in performance assessments to assure water resource protection for both human health and the environment for hundreds of years into the future. To make decisions regarding aquifer protection against potential contamination, a conceptual site model (CSM) describing the hydrodynamic behavior needs to account for subsurface heterogeneities in sufficient detail. When site-specific data are sparse, larger-scale geologic descriptions are adopted with the consequence of losing small-scale features (at the cm scale) that can control contaminant transport.

The wake maintenance zone shows task dependent changes in cognitive function following one night without sleep.

Study Objectives: The interaction between homeostatic sleep pressure and circadian timing modulates the impact of sleep deprivation on cognition. We aimed to investigate how this interaction affects different cognitive functions.

Methods: Twenty-three healthy volunteers (18 males; mean age = 25.

Performance of a prototype stationary catadioptric concentrating photovoltaic module.

A stationary catadioptric concentrating photovoltaic module with aperture area over 100 cm, geometric concentration of 180×, and collection within 60° of polar incidence was designed, prototyped, and characterized. The module performance followed modeling closely with a peak power conversion efficiency of 26% for direct irradiance. Tracking of the sun is accomplished via translational micro-tracking completely internal to the module, avoiding the cost and complexity of mechanical two-axis trackers that point towards the sun.