2,095 research outputs found
Millimeter-wave diode-grid phase shifters
Monolithic diode grids have been fabricated on 2-cm square gallium-arsenide wafers with 1600 Schottky-barrier varactor diodes. Shorted diodes are detected with a liquid-crystal technique, and the bad diodes are removed with an ultrasonic probe. A small-aperture reflectometer that uses wavefront division interference was developed to measure the reflection coefficient of the grids. A Phase shift of 70° with a 7-dB loss was obtained at 93 GHz when the bias on the diode grid was changed from -3 V to 1 V. A simple transmission-line grid model, together with the measured low-frequency parameters for the diodes, was shown to predict the measured performance over the entire capacitive bias range of the diodes, as well as over the complete reactive tuning range provided by a reflector behind the grid, and over a wide range of frequencies form 33 GHz to 141 GHz. This shows that the transmission-line model and the measured low-frequency diode parameters can be used to design an electronic beam-steering array and to predict its performance. An electronic beam-steering array made of a pair of grids using state-of-the-art diodes with 5-Ω series resistances would have a loss of 1.4 dB at 90 GHz
Millimeter-Wave Diode-Grid Frequency Doubler
Monolithic diode grid were fabricated on 2-cm^2 gallium-arsenide wafers in a proof-of-principle test of a quasi-optical varactor millimeter-wave frequency multiplier array concept. An equivalent circuit model based on a transmission-line analysis of plane wave illumination was applied to predict the array performance. The doubler experiments were performed under far-field illumination conditions. A second-harmonic conversion efficiency of 9.5% and output powers of 0.5 W were achieved at 66 GHz when the diode grid was pumped with a pulsed source at 33 GHz. This grid had 760 Schottky-barrier varactor diodes. The average series resistance was 27 Ω, the minimum capacitance was 18 fF at a reverse breakdown voltage of -3 V. The measurements indicate that the diode grid is a feasible device for generating watt-level powers at millimeter frequencies and that substantial improvement is possible by improving the diode breakdown voltage
Diode-grids for millimeter-wave phase-shifters and frequency doublers
Diode-grids have been fabricated on 2-cm square monolithic gallium-arsenide wafers with 1600 Schottky varactor-diodes. A computer-controlled reflectometer that uses a wave-front division interference technique was developed to measure the reflection coefficient of the diode-grids. A 70° phase shift with a 6-dB loss was obtained at 93 GHz when the bias on the diode-grid was changed from -3V to +1V. A second harmonic conversion efficiency of 16% and an output power of 0.5 W was obtained at 66 GHz when the diode-grid was pumped with a pulsed magnetron at 33 GHz
Z_2 Symmetry Prediction for the Leptonic Dirac CP Phase
Model-independent consequences of applying a generalized hidden horizontal
Z_2 symmetry to the neutrino mass matrix are explored. The Dirac CP phase
delta_D can be expressed in terms of the three mixing angles as 4 c_a s_a c_s
s_s s_x cos delta_D = (s^2_s - c^2_s s^2_x) (c^2_a - s^2_a) where the s_i, c_i
are sines and cosines of the atmospheric, solar, and reactor angles. This
relation is independent of neutrino masses and whether neutrinos are Dirac- or
Majorana-type. Given the present constraints on the angles, delta_D is
constrained to be almost maximal, a result which can be explored in experiments
such as NOvA and T2K. The Majorana CP phases do not receive any constraint and
are thus model-dependent. Also a distribution of theta_x with a lower limit is
obtained without specifying delta_D.Comment: 5 pages, 4 figures; Condensed version or PLB with references added;
for more details see the previous versio
The Relationship of Pyroptosis-Related Genes, Patient Outcomes, and Tumor-Infiltrating Cells in Bladder Urothelial Carcinoma (BLCA)
Introduction: The role of pyroptosis and its effects on tumor-infiltrating cells (TICs) in the pathogenesis and treatment outcomes of patients with bladder urothelial carcinoma (BLCA) remains unclear.Methods: We conducted a bioinformatics analysis on the pyroptosis-related genes (PRGs) and TICs using data from public domains, and evaluated their impact on the pathogenesis and clinical outcomes of BLCA patients. A risk score based on PRGs and a prognostic risk model that incorporated patient demographics, tumor characteristics, and differentially expressed genes (DEGs) were developed.Results: Twenty-three DEGs of 52 PRGs were identified in BLCA and normal samples from the TCGA database. Missense mutations and single nucleotide polymorphisms in PRGs are the most common genetic abnormalities. Patients with high PRG risk scores showed an inferior survival compared to those with low risk scores. The prognostic risk model based on patient demographics, tumor characteristics, and DEGs showed good predictive values for patient survival at 1, 3, and 5 years in BLCA patients. Caspase-8 (CASP8) was the only intersection gene of the prognostic genes, DEGs, and different genes expressed in tissue. Patients with a high CASP8 expression had improved survival, and an increased CASP8 expression level was observed in activated CD4 memory T cells, follicular T helper cells, resting NK cells, M0 macrophages, and activated dendritic cells. CASP8 expression also showed a positive correlation with the IL7R expression—a key cell marker of CD4 memory T cells. CASP8 expression also showed correlations with immune checkpoints (PDCD1, CD274, and CTLA4) and response to immune checkpoint inhibitors.Conclusion: Our data suggest that PRGs, especially CASP8, showed strong associations with patient outcomes and TICs in BLCA. If validated, these results could potentially aid in the prognostication and guide treatment in BLCA patients
SafetyNet: streamlining and automating QA in radiotherapy
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135420/1/acm20387-sup-0002.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135420/2/acm20387.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135420/3/acm20387-sup-0003.pd
The effects of combination canagliflozin and glucagon-like peptide-1 receptor agonist therapy on intermediate markers of cardiovascular risk in the CANVAS program
Background: Sodium glucose co-transporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP1-RA) reduce cardiovascular events, and improve intermediate markers of cardiometabolic health, in those with type 2 diabetes. We investigated these effects in the CANVAS Program. Methods and results: The CANVAS Program comprised 2 double-blind, randomized, placebo-controlled trials (CANVAS and CANVAS-R) done in patients with type 2 diabetes and elevated cardiovascular risk. Effects were estimated using mixed-effects models for continuous measures and Cox regression models for other outcomes. Randomized treatment by subgroup interaction terms were used to compare effects of canagliflozin versus placebo across subgroups defined by baseline use of GLP1-RA. There were 10,142 participants, of whom 407 (4%) were using GLP1-RA therapy at baseline. Those using GLP1-RA at baseline were less likely to have a history of cardiovascular disease (60.4% vs 65.8%), had a longer duration of diabetes (152 vs 13.5 years) and a higher body mass index (BMI; 35.6 vs 31.8 kg/m(2)) but were otherwise similar. There were greater reductions with canagliflozin versus placebo for HbA1c (-0.75% versus -0.58%; P = .0091), SBP (-6.26 versus -3.83 mmHg; P = .0018), and body weight (-3.79 versus -2.18 kg; P <.0001) in those on baseline GLP1-RA therapy. Effects across subgroups were similar for UACR (P = .21), eGFR slope (A - .72), major adverse cardiac events (P = .94) and total serious adverse events (P = .74). Conclusions: There may be a synergistic effect of SGLT2 inhibition when used on a background of GLP1-RA for intermediate cardiometabolic markers. (C) 2020 Elsevier B.V. All rights reserved
Measurements of differential cross sections of Z/gamma*+jets+X events in proton anti-proton collisions at sqrt{s}=1.96 TeV
We present cross section measurements for Z/gamma*+jets+X production,
differential in the transverse momenta of the three leading jets. The data
sample was collected with the D0 detector at the Fermilab Tevatron proton
anti-proton collider at a center-of-mass energy of 1.96 TeV and corresponds to
an integrated luminosity of 1 fb-1. Leading and next-to-leading order
perturbative QCD predictions are compared with the measurements, and agreement
is found within the theoretical and experimental uncertainties. We also make
comparisons with the predictions of four event generators. Two
parton-shower-based generators show significant shape and normalization
differences with respect to the data. In contrast, two generators combining
tree-level matrix elements with a parton shower give a reasonable description
of the the shapes observed in data, but the predicted normalizations show
significant differences with respect to the data, reflecting large scale
uncertainties. For specific choices of scales, the normalizations for either
generator can be made to agree with the measurements.Comment: Published in PLB. 11 pages, 3 figure
Measurement of the t-channel single top quark production cross section
The D0 collaboration reports direct evidence for electroweak production of
single top quarks through the t-channel exchange of a virtual W boson. This is
the first analysis to isolate an individual single top quark production
channel. We select events containing an isolated electron or muon, missing
transverse energy, and two, three or four jets from 2.3 fb^-1 of ppbar
collisions at the Fermilab Tevatron Collider. One or two of the jets are
identified as containing a b hadron. We combine three multivariate techniques
optimized for the t-channel process to measure the t- and s-channel cross
sections simultaneously. We measure cross sections of 3.14 +0.94 -0.80 pb for
the t-channel and 1.05 +-0.81 pb for the s-channel. The measured t-channel
result is found to have a significance of 4.8 standard deviations and is
consistent with the standard model prediction.Comment: 7 pages, 6 figure
Measurement of trilinear gauge boson couplings from WW + WZ to lnu jj events in pp-bar collisions at sqrt{s}=1.96 TeV
We present a direct measurement of trilinear gauge boson couplings at gammaWW
and ZWW vertices in WW and WZ events produced in pp-bar collisions at
sqrt{s}=1.96 TeV. We consider events with one electron or muon, missing
transverse energy, and at least two jets. The data were collected using the D0
detector and correspond to 1.1/fb of integrated luminosity. Considering two
different relations between the couplings at the gammaWW and ZWW vertices, we
measure these couplings at 68% C.L. to be kappa_{gamma}=1.07^{+0.26}_{-0.29},
lambda =0.00^{+0.06}_{-0.06} and g_{1}^{Z}=1.04^{+0.09}_{-0.09} in a scenario
respecting SU(2)_L x U(1)_Y gauge symmetry and kappa =1.04^{+0.11}_{-0.11} and
lambda=0.00^{+0.06}_{-0.06} in an "equal couplings" scenario.Comment: 14 pages, 7 figures, published in Phys. Rev. D, updated to published
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