Low temperature removal of surface oxides and hydrocarbons from Ge(100) using atomic hydrogen

Germanium is a group IV semiconductor with many current and potential applications in the modern semiconductor industry. Key to expanding the use of Ge is a reliable method for the removal of surface contamination, including oxides which are naturally formed during the exposure of Ge thin films to atmospheric conditions. A process for achieving this task at lower temperatures would be highly advantageous, where the underlying device architecture will not diffuse through the Ge film while also avoiding electronic damage induced by ion irradiation. Atomic hydrogen cleaning (AHC) offers a low temperature, damage-free alternative to the common ion bombardment and annealing (IBA) technique which is widely employed. In this work, we demonstrate with xray photoelectron spectroscopy (XPS) that the AHC method is effective in removing surface oxides and hydrocarbons, yielding an almost completely clean surface when the AHC is conducted at a temperature of 250 ◦C. We compare the post-AHC cleanliness and (2 × 1) low energy electron diffraction (LEED) pattern to that obtained via IBA, where the sample is annealed at 600 ◦C. We also demonstrate that the combination of a sample temperature of 250 ◦C and atomic H dosing is required to clean the surface. Lower temperatures prove less effective in removal of the oxide layer and hydrocarbons, whilst annealing in ultra-high vacuum conditions only removes weakly bound hydrocarbons. Finally, we examine the subsequent H-termination of an IBA-cleaned sample using XPS, LEED and ultraviolet photoelectron spectroscopy (UPS) in order to examine changes in the work function of Ge(100) upon hydrogenation

Severity and Treatment of Alcohol Withdrawal in Elderly Versus Younger Patients

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65425/1/j.1530-0277.1994.tb00903.x.pd

Survey of Transmission Cost Allocation Methodologies for Regional Transmission Organizations

The report presents transmission cost allocation methodologies for reliability transmission projects, generation interconnection, and economic transmission projects for all Regional Transmission Organizations

Generation Interconnection Policies and Wind Power: A Discussion of Issues, Problems, and Potential Solutions

This report describes the adoption and implementation of FERC Order 2003 and the reasons for the sharp rise in generation interconnection filings in recent years

Association of circulating sex hormones with inflammation and disease severity in patients with COVID-19

Importance: Male sex is a risk factor for developing severe COVID-19 illness. It is not known whether sex hormones contribute to this predisposition. Objective: To investigate the association of concentrations of serum testosterone, estradiol, and insulinlike growth factor 1 (IGF-1, concentrations of which are regulated by sex hormone signaling) with COVID-19 severity. Design, Setting, and Participants: This prospective cohort study was conducted using serum samples collected from consecutive patients who presented from March through May 2020 to the Barnes Jewish Hospital in St Louis, Missouri, with COVID-19 (diagnosed using nasopharyngeal swabs). Exposures: Testosterone, estradiol, and IGF-1 concentrations were measured at the time of presentation (ie, day 0) and at days 3, 7, 14, and 28 after admission (if the patient remained hospitalized). Main Outcomes and Measures: Baseline hormone concentrations were compared among patients who had severe COVID-19 vs those with milder COVID-19 illness. RNA sequencing was performed on circulating mononuclear cells to understand the mechanistic association of altered circulating hormone concentrations with cellular signaling pathways. Results: Among 152 patients (90 [59.2%] men; 62 [40.8%] women; mean [SD] age, 63 [16] years), 143 patients (94.1%) were hospitalized. Among 66 men with severe COVID-19, median [interquartile range] testosterone concentrations were lower at day 0 (53 [18 to 114] ng/dL vs 151 [95 to 217] ng/dL; P = .01) and day 3 (19 [6 to 68] ng/dL vs 111 [49 to 274] ng/dL; P = .006) compared with 24 men with milder disease. Testosterone concentrations were inversely associated with concentrations of interleukin 6 (β = -0.43; 95% CI, -0.52 to -0.17; P \u3c .001), C-reactive protein (β = -0.38; 95% CI, -0.78 to -0.16; P = .004), interleukin 1 receptor antagonist (β = -0.29; 95% CI, -0.64 to -0.06; P = .02), hepatocyte growth factor (β = -0.46; 95% CI, -0.69 to -0.25; P \u3c .001), and interferon γ-inducible protein 10 (β = -0.32; 95% CI, -0.62 to -0.10; P = .007). Estradiol and IGF-1 concentrations were not associated with COVID-19 severity in men. Testosterone, estradiol, and IGF-1 concentrations were similar in women with and without severe COVID-19. Gene set enrichment analysis revealed upregulated hormone signaling pathways in CD14+CD16- (ie, classical) monocytes and CD14-CD16+ (ie, nonclassical) monocytes in male patients with COVID-19 who needed intensive care unit treatment vs those who did not. Conclusions and Relevance: In this single-center cohort study of patients with COVID-19, lower testosterone concentrations during hospitalization were associated with increased disease severity and inflammation in men. Hormone signaling pathways in monocytes did not parallel serum hormone concentrations, and further investigation is required to understand their pathophysiologic association with COVID-19

Optimization of a high work function solution processed vanadium oxide hole-extracting layer for small molecule and polymer organic photovoltaic cells

We report a method of fabricating a high work function, solution processable vanadium oxide (V2Ox(sol)) hole-extracting layer. The atmospheric processing conditions of film preparation have a critical influence on the electronic structure and stoichiometry of the V2Ox(sol), with a direct impact on organic photovoltaic (OPV) cell performance. Combined Kelvin probe (KP) and ultraviolet photoemission spectroscopy (UPS) measurements reveal a high work function, n-type character for the thin films, analogous to previously reported thermally evaporated transition metal oxides. Additional states within the band gap of V2Ox(sol) are observed in the UPS spectra and are demonstrated using X-ray photoelectron spectroscopy (XPS) to be due to the substoichiometric nature of V2Ox(sol). The optimized V2Ox(sol) layer performance is compared directly to bare indium–tin oxide (ITO), poly(ethyleneoxythiophene):poly(styrenesulfonate) (PEDOT:PSS), and thermally evaporated molybdenum oxide (MoOx) interfaces in both small molecule/fullerene and polymer/fullerene structures. OPV cells incorporating V2Ox(sol) are reported to achieve favorable initial cell performance and cell stability attributes

Quasar accretion disk sizes from continuum reverberation mapping in the DES standard-star fields

Measurements of the physical properties of accretion disks in active galactic nuclei are important for better understanding the growth and evolution of supermassive black holes. We present the accretion disk sizes of 22 quasars from continuum reverberation mapping with data from the Dark Energy Survey (DES) standard star fields and the supernova C fields. We construct continuum lightcurves with the \textit{griz} photometry that span five seasons of DES observations. These data sample the time variability of the quasars with a cadence as short as one day, which corresponds to a rest frame cadence that is a factor of a few higher than most previous work. We derive time lags between bands with both JAVELIN and the interpolated cross-correlation function method, and fit for accretion disk sizes using the JAVELIN Thin Disk model. These new measurements include disks around black holes with masses as small as $\sim10^7$ $M_{\odot}$, which have equivalent sizes at 2500\AA \, as small as $\sim 0.1$ light days in the rest frame. We find that most objects have accretion disk sizes consistent with the prediction of the standard thin disk model when we take disk variability into account. We have also simulated the expected yield of accretion disk measurements under various observational scenarios for the Large Synoptic Survey Telescope Deep Drilling Fields. We find that the number of disk measurements would increase significantly if the default cadence is changed from three days to two days or one day.Comment: 33 pages, 24 figure

Autologous humanized PDX modeling for immuno-oncology recapitulates features of the human tumor microenvironment

BACKGROUND: Interactions between immune and tumor cells are critical to determining cancer progression and response. In addition, preclinical prediction of immune-related drug efficacy is limited by interspecies differences between human and mouse, as well as inter-person germline and somatic variation. To address these gaps, we developed an autologous system that models the tumor microenvironment (TME) from individual patients with solid tumors. METHOD: With patient-derived bone marrow hematopoietic stem and progenitor cells (HSPCs), we engrafted a patient\u27s hematopoietic system in MISTRG6 mice, followed by transfer of patient-derived xenograft (PDX) tissue, providing a fully genetically matched model to recapitulate the individual\u27s TME. We used this system to prospectively study tumor-immune interactions in patients with solid tumor. RESULTS: Autologous PDX mice generated innate and adaptive immune populations; these cells populated the TME; and tumors from autologously engrafted mice grew larger than tumors from non-engrafted littermate controls. Single-cell transcriptomics revealed a prominent vascular endothelial growth factor A (VEGFA) signature in TME myeloid cells, and inhibition of human VEGF-A abrogated enhanced growth. CONCLUSIONS: Humanization of the interleukin 6 locus in MISTRG6 mice enhances HSPC engraftment, making it feasible to model tumor-immune interactions in an autologous manner from a bedside bone marrow aspirate. The TME from these autologous tumors display hallmarks of the human TME including innate and adaptive immune activation and provide a platform for preclinical drug testing