46 research outputs found
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Experimental optimization of the FireFly 600 photovoltaic off-grid system.
A comprehensive evaluation and experimental optimization of the FireFly{trademark} 600 off-grid photovoltaic system manufactured by Energia Total, Ltd. was conducted at Sandia National Laboratories in May and June of 2001. This evaluation was conducted at the request of the manufacturer and addressed performance of individual system components, overall system functionality and performance, safety concerns, and compliance with applicable codes and standards. A primary goal of the effort was to identify areas for improvement in performance, reliability, and safety. New system test procedures were developed during the effort
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Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.
Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (nâ=â143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (nâ=â152), or no hydrocortisone (nâ=â108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (nâ=â137), shock-dependent (nâ=â146), and no (nâ=â101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707
Cortical thickness and resting-state cardiac function across the lifespan: a cross-sectional pooled mega analysis
Understanding the association between autonomic nervous system [ANS] function and brain morphology across the lifespan provides important insights into neurovisceral mechanisms underlying health and disease. Resting state ANS activity, indexed by measures of heart rate [HR] and its variability [HRV] has been associated with brain morphology, particularly cortical thickness [CT]. While findings have been mixed regarding the anatomical distribution and direction of the associations, these inconsistencies may be due to sex and age differences in HR/HRV and CT. Previous studies have been limited by small sample sizes, which impede the assessment of sex differences and aging effects on the association between ANS function and CT. To overcome these limitations, 20 groups worldwide contributed data collected under similar protocols of CT assessment and HR/HRV recording to be pooled in a mega-analysis (N = 1,218 (50.5% female), mean age 36.7 years (range: 12-87)). Findings suggest a decline in HRV as well as CT with increasing age. CT, particularly in the orbitofrontal cortex, explained additional variance in HRV, beyond the effects of aging. This pattern of results may suggest that the decline in HRV with increasing age is related to a decline in orbitofrontal CT. These effects were independent of sex and specific to HRV; with no significant association between CT and HR. Greater CT across the adult lifespan may be vital for the maintenance of healthy cardiac regulation via the ANS â or greater cardiac vagal activity as indirectly reflected in HRV may slow brain atrophy. Findings reveal an important association between cortical thickness and cardiac parasympathetic activity with implications for healthy aging and longevity that should be studied further in longitudinal research
Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19
IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19.
Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19.
DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 nonâcritically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022).
INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (nâ=â257), ARB (nâ=â248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; nâ=â10), or no RAS inhibitor (control; nâ=â264) for up to 10 days.
MAIN OUTCOMES AND MEASURES The primary outcome was organ supportâfree days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes.
RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ supportâfree days among critically ill patients was 10 (â1 to 16) in the ACE inhibitor group (nâ=â231), 8 (â1 to 17) in the ARB group (nâ=â217), and 12 (0 to 17) in the control group (nâ=â231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ supportâfree days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively).
CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes.
TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570
COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study
Background:
The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms.
Methods:
International, prospective observational study of 60â109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms.
Results:
âTypicalâ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (â€â18 years: 69, 48, 23; 85%), older adults (â„â70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each Pâ<â0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country.
Interpretation:
This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men
Leadership, Innovation, and Sustainability
In this chapter, Verburg explores the leadership challenges associated with sustainability by highlighting the current research evidence on the links between leadership, innovation, and sustainability. There seems to be a lot of conceptual confusion in relation to sustainability leadership. Different authors offer different definitions, focusing on either specific traits, styles or behaviors that they associate with sustainability leadership. Others do not even focus on leadership roles or behaviors as such but highlight the importance of any individualâs personal proactivity in order to drive sustainability agendas. This conceptual confusion may be a significant obstacle to further the field of sustainability leadership. The purpose of this chapter is, therefore, to provide a better understanding of sustainability leadership to enable future studies.Economics of Technology and Innovatio
Cortical Thickness and Resting State Cardiac Function Across the Lifespan: A Cross-Sectional Pooled Mega Analysis
Resting state autonomic nervous system activity [ANS] indexed by measures of heart rate [HR] and its variability [HRV], is associated with brain morphology, in particular cortical thickness [CT]. However, findings have been mixed regarding the regions of interest [ROI] associated with HR/HRV and the direction of the association. Sex and age differences in HR/HRV and CT may explain some of the existing inconsistencies. Understanding the association between ANS function and brain morphology across aging, may provide important insights into neurovisceral mechanisms underlying health and disease. Previous studies have been limited by small sample sizes, prohibiting the assessment of sex differences, and effects of aging, in the association between ANS function and CT. In an effort to overcome these limitations, data from researchers worldwide, applying similar protocols in the assessment of CT and recording of HR/HRV, will be pooled for a mega-analysis. This preprint details the hypotheses, strategies for pooling of data and planned analyses of this project
CT coronary angiography in patients with suspected angina due to coronary heart disease (SCOT-HEART): an open-label,parallel-group, multicentre trial
Background The benefi t of CT coronary angiography (CTCA) in patients presenting with stable chest pain has not
been systematically studied. We aimed to assess the eff ect of CTCA on the diagnosis, management, and outcome of
patients referred to the cardiology clinic with suspected angina due to coronary heart disease.
Methods In this prospective open-label, parallel-group, multicentre trial, we recruited patients aged 18â75 years referred
for the assessment of suspected angina due to coronary heart disease from 12 cardiology chest pain clinics across
Scotland. We randomly assigned (1:1) participants to standard care plus CTCA or standard care alone. Randomisation
was done with a web-based service to ensure allocation concealment. The primary endpoint was certainty of the diagnosis
of angina secondary to coronary heart disease at 6 weeks. All analyses were intention to treat, and patients were analysed
in the group they were allocated to, irrespective of compliance with scanning. This study is registered with
ClinicalTrials.gov, number NCT01149590.
Findings Between Nov 18, 2010, and Sept 24, 2014, we randomly assigned 4146 (42%) of 9849 patients who had been
referred for assessment of suspected angina due to coronary heart disease. 47% of participants had a baseline clinic
diagnosis of coronary heart disease and 36% had angina due to coronary heart disease. At 6 weeks, CTCA reclassifi ed
the diagnosis of coronary heart disease in 558 (27%) patients and the diagnosis of angina due to coronary heart
disease in 481 (23%) patients (standard care 22 [1%] and 23 [1%]; p<0·0001). Although both the certainty (relative risk
[RR] 2·56, 95% CI 2·33â2·79; p<0·0001) and frequency of coronary heart disease increased (1·09, 1·02â1·17;
p=0·0172), the certainty increased (1·79, 1·62â1·96; p<0·0001) and frequency seemed to decrease (0·93, 0·85â1·02;
p=0·1289) for the diagnosis of angina due to coronary heart disease. This changed planned investigations (15% vs 1%;
p<0·0001) and treatments (23% vs 5%; p<0·0001) but did not aff ect 6-week symptom severity or subsequent
admittances to hospital for chest pain. After 1·7 years, CTCA was associated with a 38% reduction in fatal and nonfatal
myocardial infarction (26 vs 42, HR 0·62, 95% CI 0·38â1·01; p=0·0527), but this was not signifi cant.
Interpretation In patients with suspected angina due to coronary heart disease, CTCA clarifi es the diagnosis, enables
targeting of interventions, and might reduce the future risk of myocardial infarction.
Funding The Chief Scientist Offi ce of the Scottish Government Health and Social Care Directorates funded the trial
with supplementary awards from Edinburgh and Lothianâs Health Foundation Trust and the Heart Diseases
Research Fund