Changes in the Calorimetric Value and Ignition Temperature of Composite Solid Propellants During Ageing-A Note

Calorimetric value and ignition temperature of carboxy terminated polybutadiene/ammonium perchlorate propellant decrease during accelerated ageing. The behaviour has been explained on account of binder loss and condensed phase reactions in the propellant matrix

Substantial and sustained reduction in under-5 mortality, diarrhea, and pneumonia in Oshikhandass, Pakistan : Evidence from two longitudinal cohort studies 15 years apart

Funding Information: Study 1 was funded through the Applied Diarrheal Disease Research Program at Harvard Institute for International Development with a grant from USAID (Project 936–5952, Cooperative Agreement # DPE-5952-A-00-5073-00), and the Aga Khan Health Service, Northern Areas and Chitral, Pakistan. Study 2 was funded by the Pakistan US S&T Cooperative Agreement between the Pakistan Higher Education Commission (HEC) (No.4–421/PAK-US/HEC/2010/955, grant to the Karakoram International University) and US National Academies of Science (Grant Number PGA-P211012 from NAS to the Fogarty International Center). The funding bodies had no role in the design of the study, data collection, analysis, interpretation, or writing of the manuscript. Publisher Copyright: © 2020 The Author(s).Peer reviewedPublisher PD

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 non–critically 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 (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free 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 support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (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 support–free 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

Changes in the calorimetric value and ignition temperature of composite solid propellants during ageing

Calorimetric value and ignition temp. of carboxy-terminated polybutadiene$/NH_4ClO_4$ propellant decrease during accelerated aging. The behavior is attributed to binder loss and condensed phase reactions in the propellant matri

Calorimetric values of composite solid propellants

The calorimetric values of composite solid propellant based on polystyrene, polyphenolformaldehyde, poly(vinyl chloride) and carboxy-terminated polybutadiene were determined using combustion calorimetry in order to assess the uncertainities in their measurements. The dependence of the calorimetric values on various propellant composition was obtained. The stoichiometry of oxidizer and fuel in the propellant for complete combustion obtained experimentally were compared with the theoretical stoichiometry calculated based on the oxidizer decomposition

Calorimetric values of composite solid propellants

The calorimetric values of composite solid propellant based on polystyrene, polyphenolformaldehyde, poly(vinyl chloride) and carboxy-terminated polybutadiene were determined using combustion calorimetry in order to assess the uncertainities in their measurements. The dependence of the calorimetric values on various propellant composition was obtained. The stoichiometry of oxidizer and fuel in the propellant for complete combustion obtained experimentally were compared with the theoretical stoichiometry calculated based on the oxidizer decomposition

Structural studies of oxalohydroxamic acid by single crystal x-ray diffraction and spectroscopic methods

The structure of oxalohydroxamic acid has been investigated by X-ray and spectroscopic analyses. It has been shown that oxalohydroxamic acid exists in the oxamic form in the solid as well as in solution. The variable-temperature nuclear magnetic resonance (NMR) studies reveal an exchange of OH and NH protons, the exchange being faster at higher temperatures. The kinetic and the thermodynamic parameters such as the rate constant (K), the free energy of activation $(\Delta G^{\ddagger})$, and the energy of activation $(E_a)$ for the exchange process have been obtained. The compound crystallizes in the monoclinic space group $P2_1/c$ with a=5.208, b=3.864, $c=11.482 \AA$ ,$\beta = 111.45^0$, and Z=2. The structure was solved with MULTAN 80. The refinement by block diagonal least squares and Fourier methods provided R=0.035. There is strong hydrogen bonding between the molecules which form dime

Structure of 1,2,4-oxadiazolidine-3,5-dione monohydrate

C2H2N203.H20, Mr= 120.07, monoclinic,P21/c, a= 5.011 (1), b= 11.796(2), c= 7.689 (2)A,fl= 95.22 (2) ° , V= 452.61 A 3, Z= 4, Dx= 1.76, D m = 1.75 gcm -3, /].(Cu Ks) = 1.5418 A, g = 14-0 cm -l,F(000) = 248, T = 293 K, crystal quality was poor and the final R =0.107, wR =0.090 for 881 observed reflections. The compound is derived from a novel form of the monopropellant oxalohydroxamic acid. The two exocyclic C-O bond lengths of 1.240 (3) and 1.228 (4)A indicate double bonds. The C-N bond lengths of 1.334 (4), 1.390 (4) and 1.359 (4) A are characteristic of the amide bond. The N atom covalently bonded to the two carbonyl C atoms acts as a proton donor in an intermolecular hydrogen bond to the ring O atom: N1...O3i = 2.854 ]k (i =x-- 1,y, z), H...O = 2.15 A, N-H...O = 159 °

A plausible mechanism of thermal decomposition of oxalohydroxamic acid and formation of novel products

The mechanism of thermal decomposition of oxalohydroxamic acid is proposed from the characterization of the various decomposition products with the help of crystallographic and spectroscopic investigation