76 research outputs found
Thermodynamics of formation of intermediate phases in the yttrium-iron and yttrium-cobalt systems
Solid electrolyte electromotive force cells have been used to determine the Gibbs free energies, enthalpies, and entropies of formation of binary intermediate phases in the Y-Fe and Y-Co systems. Solid CaF(,2) was used as the electrolyte, and EMF meas- urements were made over the temperature range 850 K to 1271 K with electrochemical cells of the type Y, YF(,3)(VBAR)CaF(,2)(VBAR)YF(,3), M, YM(,c) or Y, YF(,3)(VBAR)CaF(,2)(VBAR)YF(,3), YM(,a), YM(,b) where M = Fe or Co, and M and YM(,c) or YM(,a) and YM(,b) are neighboring phases in the Y-M equilibrium diagram. The data indicate that, at a given stoichiometry, the Gibbs free energy of formation becomes more negative in progression from Y-Fe to Y-Co;The experimental values for the Gibbs free energies of formation of the Y-Fe and Y-Co intermediate phases at 973 K are compared with those of the Th-Fe, Th-Co, Th-Ni, La-Co, and La-Ni systems. Examination of the trend shows that there is an empirical correlation between the Gibbs free energy of formation and the total number of valence electrons in these alloy systems;The experimental enthalpies of formation of the equiatomic alloys in the Y-Fe and Y-Co systems are compared with the theoretical pre- dictions of the Miedema and Watson-Bennett models. Experimental data for the Y-Fe system favors the Watson-Bennett approximation;in the case of the Y-Co system, however, both predictions are acceptable approximations to the experimental value; *DOE Report IS-T-1125. This work was performed under Contract W-7405-eng-82 with the U.S. Department of Energy
GASTRO RETENTIVE NON-FLOATING DRUG DELIVERY APPROACH: A REVIEW
Gastro retardation is attractive approach to enhance bioavailability of narrow absorption window drugs. Drug retardation in stomach is more beneficial for certain gastro intestinal disorders like gastro esophageal reflex disease, ulcer and other gastro intestinal conditions. Gastric site retardation is one of the challenging technique, however various techniques are applied to keep the drug and achieve the enhancement of bioavailability. To achieve gastro retentive commonly two approaches are considered, they are floating drug delivery system and non-floating gastro retentive drug delivery system. The floating drug made-up by low density polymers, this approach was not fit many of the drug molecule and floating drug has some limitations like sufficient level fluids in stomach and not to be dosed just before going to bed. In this review describe the various high density (sinking) system (non-floating) drug delivery systems like super porous hydrogels, expanding system, bio/mucoadhesives system, and magnetic system and mechanism, desirable drug characters, advantages and disadvantages. Keyword: Bioavailability, gastro retentive, magnetic system, mucoadhesive, non-floating and sinking system
Infrared Nanoimaging of Hydrogenated Perovskite Nickelate Synaptic Devices
Solid-state devices made from correlated oxides such as perovskite nickelates
are promising for neuromorphic computing by mimicking biological synaptic
function. However, comprehending dopant action at the nanoscale poses a
formidable challenge to understanding the elementary mechanisms involved. Here,
we perform operando infrared nanoimaging of hydrogen-doped correlated
perovskite, neodymium nickel oxide (H-NdNiO3) devices and reveal how an applied
field perturbs dopant distribution at the nanoscale. This perturbation leads to
stripe phases of varying conductivity perpendicular to the applied field, which
define the macroscale electrical characteristics of the devices. Hyperspectral
nano-FTIR imaging in conjunction with density functional theory calculations
unveil a real-space map of multiple vibrational states of H-NNO associated with
OH stretching modes and their dependence on the dopant concentration. Moreover,
the localization of excess charges induces an out-of-plane lattice expansion in
NNO which was confirmed by in-situ - x-ray diffraction and creates a strain
that acts as a barrier against further diffusion. Our results and the
techniques presented here hold great potential to the rapidly growing field of
memristors and neuromorphic devices wherein nanoscale ion motion is
fundamentally responsible for function.Comment: 30 pages, 5 figures in the main text and 5 figures in the
Supplementary Materia
Clinical course, therapeutic responses and outcomes in relapsing MOG antibody-associated demyelination.
Abstract
OBJECTIVE:
We characterised the clinical course, treatment and outcomes in 59 patients with relapsing myelin oligodendrocyte glycoprotein (MOG) antibody-associated demyelination.
METHODS:
We evaluated clinical phenotypes, annualised relapse rates (ARR) prior and on immunotherapy and Expanded Disability Status Scale (EDSS), in 218 demyelinating episodes from 33 paediatric and 26 adult patients.
RESULTS:
The most common initial presentation in the cohort was optic neuritis (ON) in 54% (bilateral (BON) 32%, unilateral (UON) 22%), followed by acute disseminated encephalomyelitis (ADEM) (20%), which occurred exclusively in children. ON was the dominant phenotype (UON 35%, BON 19%) of all clinical episodes. 109/226 (48%) MRIs had no brain lesions. Patients were steroid responsive, but 70% of episodes treated with oral prednisone relapsed, particularly at doses <10\u2009mg daily or within 2 months of cessation. Immunotherapy, including maintenance prednisone (P=0.0004), intravenous immunoglobulin, rituximab and mycophenolate, all reduced median ARRs on-treatment. Treatment failure rates were lower in patients on maintenance steroids (5%) compared with non-steroidal maintenance immunotherapy (38%) (P=0.016). 58% of patients experienced residual disability (average follow-up 61 months, visual loss in 24%). Patients with ON were less likely to have sustained disability defined by a final EDSS of 652 (OR 0.15, P=0.032), while those who had any myelitis were more likely to have sustained residual deficits (OR 3.56, P=0.077).
CONCLUSION:
Relapsing MOG antibody-associated demyelination is strongly associated with ON across all age groups and ADEM in children. Patients are highly responsive to steroids, but vulnerable to relapse on steroid reduction and cessation
Microarray-Based Analysis of Differential Gene Expression between Infective and Noninfective Larvae of Strongyloides stercoralis
Strongyloides stercoralis is a soil-transmitted helminth that
affects an estimated 30–100 million people worldwide. Chronically infected
persons who are exposed to corticosteroids can develop disseminated disease, which
carries a high mortality (87–100%) if untreated. Despite this, little is
known about the fundamental biology of this parasite, including the features that
enable infection. We developed the first DNA microarray for this parasite and used it
to compare infective third-stage larvae (L3i) with non-infective first stage larvae
(L1). Using this method, we identified 935 differentially expressed genes. Functional
characterization of these genes revealed L3i biased expression of heat shock proteins
and genes with products that have previously been shown to be immunoreactive in
infected humans. Genes putatively involved in transcription were found to have L1
biased expression. Potential chemotherapeutic and vaccine targets such as
far-1, ucr 2.1 and hsp-90 were
identified for further study
Isotopic characterization of aerosol organic carbon components over the eastern United States
Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 117 (2012): D13303, doi:10.1029/2011JD017153.Carbon isotopic signatures (δ13C, Δ14C) of aerosol particulate matter total organic carbon (TOC) and operationally defined organic carbon (OC) components were measured in samples from two background sites in the eastern U.S. TOC and water-soluble OC (WSOC) δ13C values (−27 to −24‰) indicated predominantly terrestrial C3 plant and fossil derived sources. Total solvent extracts (TSE) and their aliphatic, aromatic, and polar OC components were depleted in δ13C (−30 to −26‰) relative to TOC and WSOC. Δ14C signatures of aerosol TOC and TSE (−476 to +25‰) suggest variable fossil contributions (~5–50%) to these components. Aliphatic OC while comprising a small portion of the TOC (<1%), was dominated by fossil-derived carbon (86 ± 3%), indicating its potential utility as a tracer for fossil aerosol OC inputs. In contrast, aromatic OC contributions (<1.5%) contained approximately equal portions contemporary (52 ± 8%) and fossil (48 ± 8%) OC. The quantitatively significant polar OC fraction (6–25% of TOC) had fossil contributions (30 ± 12%) similar to TOC (26 ± 7%) and TSE (28 ± 9%). Thus, much of both of the fossil and contemporary OC is deduced to be oxidized, polar material. Aerosol WSOC consistently showed low fossil content (<8%) relative to the TOC (5–50%) indicating that the majority of fossil OC in aerosol particulates is insoluble. Therefore, on the basis of solubility and polarity, aerosols are predicted to partition differently once deposited to watersheds, and these chemically distinct components are predicted to contribute in quantitatively and qualitatively different ways to watershed carbon biogeochemistry and cycling.ASW was partially supported by a Graduate
Fellowship from the Hudson River Foundation during the course of this
study. Additional funding for this work came from a NOSAMS student
internship award, a fellowship award from Sun Trust Bank administered
through the VIMS Foundation, a student research grant from VIMS, and
the following NSF awards: DEB Ecosystems grant DEB-0234533, Chemical
Oceanography grant OCE-0327423, and Integrated Carbon Cycle
Research Program grant EAR-0403949 to JEB; and Chemical Oceanography
grant OCE-0727575 to RMD and JEB.2013-01-0
The Acute Optic Neuritis Network (ACON): Study protocol of a non-interventional prospective multicenter study on diagnosis and treatment of acute optic neuritis
Optic neuritis (ON) often occurs at the presentation of multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), and myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD). The recommended treatment of high-dose corticosteroids for ON is based on a North American study population, which did not address treatment timing or antibody serostatus. The Acute Optic Neuritis Network (ACON) presents a global, prospective, observational study protocol primarily designed to investigate the effect of time to high-dose corticosteroid treatment on 6-month visual outcomes in ON. Patients presenting within 30 days of the inaugural ON will be enrolled. For the primary analysis, patients will subsequently be assigned into the MS-ON group, the aquapotin-4-IgG positive ON (AQP4-IgG+ON) group or the MOG-IgG positive ON (MOG-IgG+ON) group and then further sub-stratified according to the number of days from the onset of visual loss to high-dose corticosteroids (days-to-Rx). The primary outcome measure will be high-contrast best-corrected visual acuity (HC-BCVA) at 6 months. In addition, multimodal data will be collected in subjects with any ON (CIS-ON, MS-ON, AQP4-IgG+ON or MOG-IgG+ON, and seronegative non-MS-ON), excluding infectious and granulomatous ON. Secondary outcomes include low-contrast best-corrected visual acuity (LC-BCVA), optical coherence tomography (OCT), magnetic resonance imaging (MRI) measurements, serum and cerebrospinal fluid (CSF) biomarkers (AQP4-IgG and MOG-IgG levels, neurofilament, and glial fibrillary protein), and patient reported outcome measures (headache, visual function in daily routine, depression, and quality of life questionnaires) at presentation at 6-month and 12-month follow-up visits. Data will be collected from 28 academic hospitals from Africa, Asia, the Middle East, Europe, North America, South America, and Australia. Planned recruitment consists of 100 MS-ON, 50 AQP4-IgG+ON, and 50 MOG-IgG+ON. This prospective, multimodal data collection will assess the potential value of early high-dose corticosteroid treatment, investigate the interrelations between functional impairments and structural changes, and evaluate the diagnostic yield of laboratory biomarkers. This analysis has the ability to substantially improve treatment strategies and the accuracy of diagnostic stratification in acute demyelinating ON
The Acute Optic Neuritis Network (ACON): Study protocol of a non-interventional prospective multicenter study on diagnosis and treatment of acute optic neuritis
Optic neuritis (ON) often occurs at the presentation of multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), and myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD). The recommended treatment of high-dose corticosteroids for ON is based on a North American study population, which did not address treatment timing or antibody serostatus. The Acute Optic Neuritis Network (ACON) presents a global, prospective, observational study protocol primarily designed to investigate the effect of time to high-dose corticosteroid treatment on 6-month visual outcomes in ON. Patients presenting within 30 days of the inaugural ON will be enrolled. For the primary analysis, patients will subsequently be assigned into the MS-ON group, the aquapotin-4-IgG positive ON (AQP4-IgG+ON) group or the MOG-IgG positive ON (MOG-IgG+ON) group and then further sub-stratified according to the number of days from the onset of visual loss to high-dose corticosteroids (days-to-Rx). The primary outcome measure will be high-contrast best-corrected visual acuity (HC-BCVA) at 6 months. In addition, multimodal data will be collected in subjects with any ON (CIS-ON, MS-ON, AQP4-IgG+ON or MOG-IgG+ON, and seronegative non-MS-ON), excluding infectious and granulomatous ON. Secondary outcomes include low-contrast best-corrected visual acuity (LC-BCVA), optical coherence tomography (OCT), magnetic resonance imaging (MRI) measurements, serum and cerebrospinal fluid (CSF) biomarkers (AQP4-IgG and MOG-IgG levels, neurofilament, and glial fibrillary protein), and patient reported outcome measures (headache, visual function in daily routine, depression, and quality of life questionnaires) at presentation at 6-month and 12-month follow-up visits. Data will be collected from 28 academic hospitals from Africa, Asia, the Middle East, Europe, North America, South America, and Australia. Planned recruitment consists of 100 MS-ON, 50 AQP4-IgG+ON, and 50 MOG-IgG+ON. This prospective, multimodal data collection will assess the potential value of early high-dose corticosteroid treatment, investigate the interrelations between functional impairments and structural changes, and evaluate the diagnostic yield of laboratory biomarkers. This analysis has the ability to substantially improve treatment strategies and the accuracy of diagnostic stratification in acute demyelinating ON. Trial registration: ClinicalTrials.gov, identifier: NCT05605951
Extracorporeal Membrane Oxygenation for Acute Pediatric Respiratory Failure
This article is made available for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.The use of extracorporeal membrane oxygenation (ECMO) to support children with acute respiratory failure has steadily increased over the past several decades, with major advancements having been made in the care of these children. There are, however, many controversies regarding indications for initiating ECMO in this setting and the appropriate management strategies thereafter. Broad indications for ECMO include hypoxia, hypercarbia, and severe air leak syndrome, with hypoxia being the most common. There are many disease-specific considerations when evaluating children for ECMO, but there are currently very few, if any, absolute contraindications. Venovenous rather than veno-arterial ECMO cannulation is the preferred configuration for ECMO support of acute respiratory failure due to its superior side-effect profile. The approach to lung management on ECMO is variable and should be individualized to the patient, with the main goal of reducing the risk of VILI. ECMO is a relatively rare intervention, and there are likely a minimum number of cases per year at a given center to maintain competency. Patients who have prolonged ECMO runs (i.e., greater than 21 days) are less likely to survive, though no absolute duration of ECMO that would mandate withdrawal of ECMO support can be currently recommended
Correlates of Lifetime History of Purchasing Sex Services by Men in Saint Petersburg and Leningrad Oblast, Russia
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