72 research outputs found
Absolute Energy Measurements with Superconducting Transition-Edge Sensors for Muonic X-ray Spectroscopy at 44 keV
Superconducting transition-edge sensor (TES) microcalorimeters have great
utility in x-ray applications owing to their high energy resolution, good
collecting efficiency and the feasibility of being multiplexed into large
arrays. In this work, we develop hard x-ray TESs to measure the absolute
energies of muonic-argon (-Ar) transition lines around 44 keV and 20 keV.
TESs with sidecar absorbers of different heat capacities were fabricated and
characterized for their energy resolution and calibration uncertainty. We
achieved ~ 1 eV absolute energy measurement accuracy at 44 keV, and < 12 eV
energy resolution at 17.5 keV
A Tabletop X-Ray Tomography Instrument for Nanometer-Scale Imaging: Integration of a Scanning Electron Microscope with a Transition-Edge Sensor Spectrometer
X-ray nanotomography is a powerful tool for the characterization of nanoscale
materials and structures, but is difficult to implement due to competing
requirements on X-ray flux and spot size. Due to this constraint,
state-of-the-art nanotomography is predominantly performed at large synchrotron
facilities. Compact X-ray nanotomography tools operated in standard analysis
laboratories exist, but are limited by X-ray optics and destructive sample
preparation techniques. We present a laboratory-scale nanotomography instrument
that achieves nanoscale spatial resolution while changing the limitations of
conventional tomography tools. The instrument combines the electron beam of a
scanning electron microscope (SEM) with the precise, broadband X-ray detection
of a superconducting transition-edge sensor (TES) microcalorimeter. The
electron beam generates a highly focused X-ray spot in a metal target, while
the TES spectrometer isolates target photons with high signal-to-noise. This
combination of a focused X-ray spot, energy-resolved X-ray detection, and
unique system geometry enable nanoscale, element-specific X-ray imaging in a
compact footprint. The proof-of-concept for this approach to X-ray
nanotomography is demonstrated by imaging 160 nm features in three dimensions
in a Cu-SiO2 integrated circuit, and a path towards finer resolution and
enhanced imaging capabilities is discussed.Comment: The following article has been submitted to Physical Review Applie
A tabletop x-ray tomography instrument for nanometer-scale imaging: demonstration of the 1,000-element transition-edge sensor subarray
We report on the 1,000-element transition-edge sensor (TES) x-ray
spectrometer implementation of the TOMographic Circuit Analysis Tool (TOMCAT).
TOMCAT combines a high spatial resolution scanning electron microscope (SEM)
with a highly efficient and pixelated TES spectrometer to reconstruct
three-dimensional maps of nanoscale integrated circuits (ICs). A 240-pixel
prototype spectrometer was recently used to reconstruct ICs at the 130 nm
technology node, but to increase imaging speed to more practical levels, the
detector efficiency needs to be improved. For this reason, we are building a
spectrometer that will eventually contain 3,000 TES microcalorimeters read out
with microwave superconducting quantum interference device (SQUID)
multiplexing, and we currently have commissioned a 1,000 TES subarray. This
still represents a significant improvement from the 240-pixel system and allows
us to begin characterizing the full spectrometer performance. Of the 992
maximimum available readout channels, we have yielded 818 devices, representing
the largest number of TES x-ray microcalorimeters simultaneously read out to
date. These microcalorimeters have been optimized for pulse speed rather than
purely energy resolution, and we measure a FWHM energy resolution of 14 eV at
the 8.0 keV Cu K line.Comment: 5 pages, 4 figures, submitted to IEEE Transactions on Applied
Superconductivit
Albiglutide and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease (Harmony Outcomes): a double-blind, randomised placebo-controlled trial
Background:
Glucagon-like peptide 1 receptor agonists differ in chemical structure, duration of action, and in their effects on clinical outcomes. The cardiovascular effects of once-weekly albiglutide in type 2 diabetes are unknown. We aimed to determine the safety and efficacy of albiglutide in preventing cardiovascular death, myocardial infarction, or stroke.
Methods:
We did a double-blind, randomised, placebo-controlled trial in 610 sites across 28 countries. We randomly assigned patients aged 40 years and older with type 2 diabetes and cardiovascular disease (at a 1:1 ratio) to groups that either received a subcutaneous injection of albiglutide (30–50 mg, based on glycaemic response and tolerability) or of a matched volume of placebo once a week, in addition to their standard care. Investigators used an interactive voice or web response system to obtain treatment assignment, and patients and all study investigators were masked to their treatment allocation. We hypothesised that albiglutide would be non-inferior to placebo for the primary outcome of the first occurrence of cardiovascular death, myocardial infarction, or stroke, which was assessed in the intention-to-treat population. If non-inferiority was confirmed by an upper limit of the 95% CI for a hazard ratio of less than 1·30, closed testing for superiority was prespecified. This study is registered with ClinicalTrials.gov, number NCT02465515.
Findings:
Patients were screened between July 1, 2015, and Nov 24, 2016. 10 793 patients were screened and 9463 participants were enrolled and randomly assigned to groups: 4731 patients were assigned to receive albiglutide and 4732 patients to receive placebo. On Nov 8, 2017, it was determined that 611 primary endpoints and a median follow-up of at least 1·5 years had accrued, and participants returned for a final visit and discontinuation from study treatment; the last patient visit was on March 12, 2018. These 9463 patients, the intention-to-treat population, were evaluated for a median duration of 1·6 years and were assessed for the primary outcome. The primary composite outcome occurred in 338 (7%) of 4731 patients at an incidence rate of 4·6 events per 100 person-years in the albiglutide group and in 428 (9%) of 4732 patients at an incidence rate of 5·9 events per 100 person-years in the placebo group (hazard ratio 0·78, 95% CI 0·68–0·90), which indicated that albiglutide was superior to placebo (p<0·0001 for non-inferiority; p=0·0006 for superiority). The incidence of acute pancreatitis (ten patients in the albiglutide group and seven patients in the placebo group), pancreatic cancer (six patients in the albiglutide group and five patients in the placebo group), medullary thyroid carcinoma (zero patients in both groups), and other serious adverse events did not differ between the two groups. There were three (<1%) deaths in the placebo group that were assessed by investigators, who were masked to study drug assignment, to be treatment-related and two (<1%) deaths in the albiglutide group.
Interpretation:
In patients with type 2 diabetes and cardiovascular disease, albiglutide was superior to placebo with respect to major adverse cardiovascular events. Evidence-based glucagon-like peptide 1 receptor agonists should therefore be considered as part of a comprehensive strategy to reduce the risk of cardiovascular events in patients with type 2 diabetes.
Funding:
GlaxoSmithKline
Riociguat treatment in patients with chronic thromboembolic pulmonary hypertension: Final safety data from the EXPERT registry
Objective: The soluble guanylate cyclase stimulator riociguat is approved for the treatment of adult patients with pulmonary arterial hypertension (PAH) and inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH) following Phase
New horizons for fundamental physics with LISA
The Laser Interferometer Space Antenna (LISA) has the potential to reveal wonders about the fundamental theory of nature at play in the extreme gravity regime, where the gravitational interaction is both strong and dynamical. In this white paper, the Fundamental Physics Working Group of the LISA Consortium summarizes the current topics in fundamental physics where LISA observations of gravitational waves can be expected to provide key input. We provide the briefest of reviews to then delineate avenues for future research directions and to discuss connections between this working group, other working groups and the consortium work package teams. These connections must be developed for LISA to live up to its science potential in these areas
Potential Role for CD63 in CCR5-Mediated Human Immunodeficiency Virus Type 1 Infection of Macrophages
Macrophages and CD4(+) lymphocytes are the principal target cells for human immunodeficiency virus type 1 (HIV-1) infection, but the molecular details of infection may differ between these cell types. During studies to identify cellular molecules that could be involved in macrophage infection, we observed inhibition of HIV-1 infection of macrophages by monoclonal antibody (MAb) to the tetraspan transmembrane glycoprotein CD63. Pretreatment of primary macrophages with anti-CD63 MAb, but not MAbs to other macrophage cell surface tetraspanins (CD9, CD81, and CD82), was shown to inhibit infection by several R5 and dualtropic strains, but not by X4 isolates. The block to productive infection was postfusion, as assessed by macrophage cell-cell fusion assays, but was prior to reverse transcription, as determined by quantitative PCR assay for new viral DNA formation. The inhibitory effects of anti-CD63 in primary macrophages could not be explained by changes in the levels of CD4, CCR5, or β-chemokines. Infections of peripheral blood lymphocytes and certain cell lines were unaffected by treatment with anti-CD63, suggesting that the role of CD63 in HIV-1 infection may be specific for macrophages
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