182 research outputs found
DARPA Phoenix Payload Orbital Delivery System: Progress towards Small Satellite Access to GEO
The emerging practice of hosting payloads on commercial geosynchronous Earth orbit (GEO) satellites is gaining traction throughout the space community because of the flight opportunities and budgetary savings that it offers. Using the hosted payload model, the DARPA Phoenix Payload Orbital Delivery (POD) system is meant to enable a higher tempo to GEO for small‐mass hardware items. The POD system proposes a departure from the typical hosted payload. The POD would provide a controlled release of the hosted payload from the commercial host near GEO. The POD standard user\u27s guide developed under the Phoenix program ensures compatibility with most of the approximately 15 commercial launches to GEO each year. By hosting with a standard user’s guide, commercial satellite providers would be capable of bringing hosted payloads quite late into the typical launch integration cycle. The combination of hightempo commercial launches and late integration would create an “express delivery” capability to GEO orbit. This POD capability would continue the paradigm shift of working with the commercial satellite provider directly to leverage the efficiencies of mass to orbit, reducing interactions with the launch provider. Phoenix is completing the design and ground testing of the POD system to help make access to new orbits more affordable and more routine for small‐mass systems
Breast MRI and tumour biology predict axillary lymph node response to neoadjuvant chemotherapy for breast cancer
Beyond gene-disease validity: capturing structured data on inheritance, allelic requirement, disease-relevant variant classes, and disease mechanism for inherited cardiac conditions
Background:
As the availability of genomic testing grows, variant interpretation will increasingly be performed by genomic generalists, rather than domain-specific experts. Demand is rising for laboratories to accurately classify variants in inherited cardiac condition (ICC) genes, including secondary findings.
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Methods:
We analyse evidence for inheritance patterns, allelic requirement, disease mechanism and disease-relevant variant classes for 65 ClinGen-curated ICC gene-disease pairs. We present this information for the first time in a structured dataset, CardiacG2P, and assess application in genomic variant filtering.
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Results:
For 36/65 gene-disease pairs, loss of function is not an established disease mechanism, and protein truncating variants are not known to be pathogenic. Using the CardiacG2P dataset as an initial variant filter allows for efficient variant prioritisation whilst maintaining a high sensitivity for retaining pathogenic variants compared with two other variant filtering approaches.
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Conclusions:
Access to evidence-based structured data representing disease mechanism and allelic requirement aids variant filtering and analysis and is a pre-requisite for scalable genomic testing
Commercial Immunoglobulin Products Contain Neutralizing Antibodies Against Severe Acute Respiratory Syndrome Coronavirus 2 Spike Protein
BACKGROUND: Patients with antibody deficiency respond poorly to COVID-19 vaccination and are at risk of severe or prolonged infection. They are given long-term immunoglobulin replacement therapy (IRT) prepared from healthy donor plasma to confer passive immunity against infection. Following widespread COVID-19 vaccination alongside natural exposure, we hypothesised that immunoglobulin preparations will now contain neutralising SARS-CoV-2 spike antibodies which confer protection against COVID-19 disease and may help to treat chronic infection. METHODS: We evaluated anti-SARS-CoV-2 spike antibody in a cohort of patients before and after immunoglobulin infusion. Neutralising capacity of patient samples and immunoglobulin products was assessed using in vitro pseudo-virus and live-virus neutralisation assays, the latter investigating multiple batches against current circulating omicron variants. We describe the clinical course of nine patients started on IRT during treatment of COVID-19. RESULTS: In 35 individuals with antibody deficiency established on IRT, median anti-spike antibody titre increased from 2123 to 10600 U/ml post-infusion, with corresponding increase in pseudo-virus neutralisation titres to levels comparable to healthy donors. Testing immunoglobulin products directly in the live-virus assay confirmed neutralisation, including of BQ1.1 and XBB variants, but with variation between immunoglobulin products and batches.Initiation of IRT alongside Remdesivir in patients with antibody deficiency and prolonged COVID-19 infection (median 189 days, maximum over 900 days with an ancestral viral strain) resulted in clearance of SARS-CoV-2 virus at a median of 20 days. CONCLUSIONS: Immunoglobulin preparations now contain neutralising anti-SARS-CoV-2 antibodies which are transmitted to patients and help to treat COVID-19 in individuals with failure of humoral immunity
A programme theory for liaison mental health services in England
Background:
Mechanisms by which liaison mental health services (LMHS) may bring about improved patient and organisational outcomes are poorly understood. A small number of logic models have been developed, but they fail to capture the complexity of clinical practice.
Method:
We synthesised data from a variety of sources including a large national survey, 73 in-depth interviews with acute and liaison staff working in hospitals with different types of liaison mental health services, and relevant local, national and international literature. We generated logic models for two common performance indicators used to assess organisational outcomes for LMHS: response times in the emergency department and hospital length of stay for people with mental health problems.
Results:
We identified 8 areas of complexity that influence performance, and 6 trade-offs which drove the models in different directions depending upon the balance of the trade-off. The logic models we developed could only be captured by consideration of more than one pass through the system, the complexity in which they operated, and the trade-offs that occurred.
Conclusions:
Our findings are important for commissioners of liaison services. Reliance on simple target setting may result in services that are unbalanced and not patient-centred. Targets need to be reviewed on a regular basis, together with other data that reflect the wider impact of the service, and any external changes in the system that affect the performance of LMHS, which are beyond their control
Cosmological Constraints from the SDSS Luminous Red Galaxies
We measure the large-scale real-space power spectrum P(k) using luminous red
galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS) and use this measurement
to sharpen constraints on cosmological parameters from the Wilkinson Microwave
Anisotropy Probe (WMAP). We employ a matrix-based power spectrum estimation
method using Pseudo-Karhunen-Loeve eigenmodes, producing uncorrelated
minimum-variance measurements in 20 k-bands of both the clustering power and
its anisotropy due to redshift-space distortions, with narrow and well-behaved
window functions in the range 0.01h/Mpc < k < 0.2h/Mpc. Results from the LRG
and main galaxy samples are consistent, with the former providing higher
signal-to-noise. Our results are robust to omitting angular and radial density
fluctuations and are consistent between different parts of the sky. They
provide a striking confirmation of the predicted large-scale LCDM power
spectrum.
Combining only SDSS LRG and WMAP data places robust constraints on many
cosmological parameters that complement prior analyses of multiple data sets.
The LRGs provide independent cross-checks on Om and the baryon fraction in good
agreement with WMAP. Within the context of flat LCDM models, our LRG
measurements complement WMAP by sharpening the constraints on the matter
density, the neutrino density and the tensor amplitude by about a factor of
two, giving Omega_m=0.24+-0.02 (1 sigma), sum m_nu < 0.9 eV (95%) and r<0.3
(95%). Baryon oscillations are clearly detected and provide a robust
measurement of the comoving distance to the median survey redshift z=0.35
independent of curvature and dark energy properties. Within the LCDM framework,
our power spectrum measurement improves the evidence for spatial flatness,
sharpening the curvature constraint Omega_tot=1.05+-0.05 from WMAP alone to
Omega_tot=1.003+-0.010. Assuming Omega_tot=1, the equation of state parameter
is constrained to w=-0.94+-0.09, indicating the potential for more ambitious
future LRG measurements to provide precision tests of the nature of dark
energy. All these constraints are essentially independent of scales k>0.1h/Mpc
and associated nonlinear complications, yet agree well with more aggressive
published analyses where nonlinear modeling is crucial.Comment: Matches accepted PRD version. SDSS data, likelihood code, Markov
chains and ppt figures available at
http://space.mit.edu/home/tegmark/sdss.html 36 journal pages, 25 figs.
CosmoMC plugin at http://cosmologist.info/cosmomc
Long-Term Blocking of Calcium Channels in mdx Mice Results in Differential Effects on Heart and Skeletal Muscle
The disease mechanisms underlying dystrophin-deficient muscular dystrophy are complex, involving not only muscle membrane fragility, but also dysregulated calcium homeostasis. Specifically, it has been proposed that calcium channels directly initiate a cascade of pathological events by allowing calcium ions to enter the cell. The objective of this study was to investigate the effect of chronically blocking calcium channels with the aminoglycoside antibiotic streptomycin from onset of disease in the mdx mouse model of Duchenne muscular dystrophy (DMD)
Arrhythmic risk prediction in arrhythmogenic right ventricular cardiomyopathy: external validation of the arrhythmogenic right ventricular cardiomyopathy risk calculator
Aims Arrhythmogenic right ventricular cardiomyopathy (ARVC) causes ventricular arrhythmias (VAs) and sudden cardiac death (SCD). In 2019, a risk prediction model that estimates the 5-year risk of incident VAs in ARVC was developed (ARVCrisk.com). This study aimed to externally validate this prediction model in a large international multicentre cohort and to compare its performance with the risk factor approach recommended for implantable cardioverter-defibrillator (ICD) use by published guidelines and expert consensus.Methods and results In a retrospective cohort of 429 individuals from 29 centres in North America and Europe, 103 (24%) experienced sustained VA during a median follow-up of 5.02 (2.05-7.90) years following diagnosis of ARVC. External validation yielded good discrimination [C-index of 0.70 (95% confidence interval-CI 0.65-0.75)] and calibration slope of 1.01 (95% CI 0.99-1.03). Compared with the three published consensus-based decision algorithms for ICD use in ARVC (Heart Rhythm Society consensus on arrhythmogenic cardiomyopathy, International Task Force consensus statement on the treatment of ARVC, and American Heart Association guidelines for VA and SCD), the risk calculator performed better with a superior net clinical benefit below risk threshold of 35%.Conclusion Using a large independent cohort of patients, this study shows that the ARVC risk model provides good prognostic information and outperforms other published decision algorithms for ICD use. These findings support the use of the model to facilitate shared decision making regarding ICD implantation in the primary prevention of SCD in ARVC
A Phase II Randomized, Double-Blind, Multicenter Study to Evaluate Efficacy and Safety of Intravenous Iclaprim Versus Vancomycin for the Treatment of Nosocomial Pneumonia Suspected or Confirmed to be Due to Gram-Positive Pathogens
Purpose: The primary objective of this Phase II study was to compare the clinical cure rates of 2 iclaprim dosages versus vancomycin in the treatment of patients with nosocomial pneumonia suspected or confirmed to be caused by gram-positive pathogens. Methods: This study was a double-blind, randomized, multicenter trial. A total of 70 patients were randomized 1:1:1 to receive iclaprim 0.8 mg/kg IV q12h (iclaprim q12h; n = 23), iclaprim 1.2 mg/kg IV q8h (iclaprim q8h; n = 24), or vancomycin 1 g IV q12h (vancomycin; n = 23) for 7 to 14 days. The primary end point was clinical cure in the intention-to-treat population at test of cure (TOC; 7 [1] days’ posttreatment) visit. Findings: The baseline and demographic characteristics of patients treated with either iclaprim or vancomycin were comparable. Cure rates in the intention-to-treat population were 73.9% (17 of 23), 62.5% (15 of 24), and 52.2% (12 of 23) at the TOC visit in the iclaprim q12h, iclaprim q8h, and vancomycin groups, respectively (iclaprim q12h vs vancomycin, P = 0.13; iclaprim q8h vs vancomycin, P = 0.47). The death rates within 28 days of the start of treatment were 8.7% (2 of 23), 12.5% (3 of 24), and 21.7% (5 of 23) for the iclaprim q12h, iclaprim q8h, and vancomycin groups (no statistically significant differences). The adverse event profile of both iclaprim dosing regimens was similar to that of vancomycin. Implications: Iclaprim had clinical cure rates and a safety profile comparable with vancomycin among patients with nosocomial pneumonia. Iclaprim could be an important new therapeutic option for the treatment of nosocomial pneumonia, and a pivotal clinical trial is warranted to evaluate its safety and efficacy in this indication
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