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•Orientational structure and dynamics of four molecules in ZSM5 is studied separately.•The selected molecules have similar kinetic diameters and moments of inertia but different ...shapes.•Rotation of all four molecules confined in ZSM5 occurs at two different time scales.•Effect of molecular shape on the orientational structure and dynamics is studied.•Asymmetry of charge distribution plays a determining role in the rotational behavior of confined molecules.
Orientational structure and dynamics of molecules is known to be affected by confinement in space comparable in size to the molecule itself. ZSM-5 with porous channels of ≈0.55 nm is such a porous medium, which offers a strict spatial confinement on low molecular weight hydrocarbons. An important factor that determines these properties is the shape of the confined molecules. We employed molecular dynamics simulation to study the orientational structure and dynamics of four molecules that differ in shape but have similar kinetic diameters and moments of inertia, confined in ZSM-5. The effect of molecular shape on the orientational structure and dynamics of propane, acetonitrile, acetaldehyde and acetone in ZSM-5 is studied by means of probing the differences in the orientational distribution of molecules in the ZSM-5 channels, and extracting time scales of the decay of correlation functions related to rotational motion. Orientational correlation functions of all the four molecules exhibit two regimes of rotational motion. While the short time regime represents free rotation of the molecules before they collide with the pore walls, the long time orientational jumps driven by inter-channel migrations give rise to a very slow varying second regime. Of the molecules studied, orientational structure and dynamics of propane is found to be least affected by confinement under ZSM-5, whereas charge and shape asymmetry of other molecules makes their interchannel migration-driven rotation slow. The time scales involved in the rotational motion for the molecules studied are compared with similar studies reported in literature. This study reveals the important role that molecular shape plays in the behavior of confined molecules.
COVID-19 convalescent plasma (CCP) was an early and widely adopted putative therapy for severe COVID-19. Results from randomized control trials and observational studies have failed to demonstrate a ...clear therapeutic role for CCP for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Underlying these inconclusive findings is a broad heterogeneity in the concentrations of neutralizing antibodies (nAbs) between different CCP donors. We conducted this study to evaluate the effectiveness and safety of nAb titer-defined CCP in adults admitted to an academic referral hospital. Patients positive by a SARS-CoV-2 nucleic acid amplification test and with symptoms for <10 days were eligible. Participants received either CCP with nAb titers of >1:640 (high-titer group) or ≥1:160 to 1:640 (standard-titer group) in addition to standard of care treatments. The primary clinical outcome was time to hospital discharge, with mortality and respiratory support evaluated as secondary outcomes. Adverse events were contrasted by CCP titer. Between 28 August and 4 December 2020, 316 participants were screened, and 55 received CCP, with 14 and 41 receiving high- versus standard-titer CCP, respectively. Time to hospital discharge was shorter among participants receiving high- versus standard-titer CCP, accounting for death as a competing event (hazard ratio, 1.94; 95% confidence interval CI, 1.05 to 3.58; Gray's
= 0.02). Severe adverse events (SAEs) (≥grade 3) occurred in 4 (29%) and 23 (56%) of participants receiving the high versus standard titer, respectively, by day 28 (risk ratio, 0.51; 95% CI, 0.21 to 1.22; Fisher's
= 0.12). There were no observed treatment-related AEs. (This study has been registered at ClinicalTrials.gov under registration no. NCT04524507).
In this study, in a high-risk population of patients admitted for COVID-19, we found an earlier time to hospital discharge among participants receiving CCP with nAb titers of >1:640 compared with participants receiving CCP with a lower nAb titer and no CCP-related AEs. The significance of our research is in identifying a dose response of CCP and clinical outcomes based on nAb titer. Although limited by a small study size, these findings support further study of high-nAb-titer CCP defined as >1:640 in the treatment of COVID-19.
The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) has now caused over 2 million deaths worldwide and continues to ...expand. Currently, much is unknown about functionally neutralizing human antibody responses and durability to SARS-CoV-2 months after infection or the reason for the discrepancy in COVID-19 disease and sex. Using convalescent-phase sera collected from 101 COVID-19-recovered individuals 21 to 212 days after symptom onset with 48 additional longitudinal samples, we measured functionality and durability of serum antibodies. We also evaluated associations of individual demographic and clinical parameters with functional neutralizing antibody responses to COVID-19. We found robust antibody durability out to 6 months, as well as significant positive associations with the magnitude of the neutralizing antibody response and male sex and in individuals with cardiometabolic comorbidities.
In this study, we found that neutralizing antibody responses in COVID-19-convalescent individuals vary in magnitude but are durable and correlate well with receptor binding domain (RBD) Ig binding antibody levels compared to other SARS-CoV-2 antigen responses. In our cohort, higher neutralizing antibody titers are independently and significantly associated with male sex compared to female sex. We also show for the first time that higher convalescent antibody titers in male donors are associated with increased age and symptom grade. Furthermore, cardiometabolic comorbidities are associated with higher antibody titers independently of sex. Here, we present an in-depth evaluation of serologic, demographic, and clinical correlates of functional antibody responses and durability to SARS-CoV-2 which supports the growing literature on sex discrepancies regarding COVID-19 disease morbidity and mortality, as well as functional neutralizing antibody responses to SARS-CoV-2.
The most common cause of mortality in chronic kidney disease patients is cardiovascular events. Cardiovascular autonomic dysfunction is likely to contribute high incidence of cardiovascular ...mortality, and in addition to adrenergic overdrive in these patients, there is the presence of impaired reflex control of both sympathetic and parasympathetic outflow to the heart and vasculature. Very few studies are available which show that renal transplantation (RT) improves the baroreflex function along with improvement in cardiovascular variability parameters. This prospective study was designed for the assessment of the autonomic function, i.e., heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) in end-stage renal disease (ESRD) patients before RT and three and six months after RT and to study the effects of RT on cardiac and vascular autonomic tone and on BRS. We studied 81 ESRD patients prospectively slated for RT but only 64 patients (mean age: 33 years) completed both three and six months visits after RT for autonomic function study. Patients were evaluated in detail clinically as well as routine biochemical parameters were done on every three visits. Baroreflex function was quantified by the sequence method. Assessment of short-term HRV and BPV were done using power spectrum analysis of RR intervals and systolic BP by frequency domain analysis. The parameters of HRV after RT showed significant changes in high-frequency domain measures six months post-RT but not in low frequency. HRV in total power was also statistically significant as early as three months postrenal transplant and remained at six months. The favorable effect of RT on decreasing BPV and improving BRS is seen by as early as three months.
Cardiovascular diseases are an important cause of mortality in end-stage renal disease (ESRD) and increased arterial stiffness and autonomic dysfunction have been proposed to explain part of this ...excess cardiovascular risk. This prospective study was designed with the aim of noninvasive assessment of the vascular function, i.e., arterial stiffness in the form of pulse wave velocity (PWV) and autonomic function in the form of baroreflex sensitivity (BRS) in ESRD patients before renal transplantation (RT) and three and six months after RT. The study was conducted in 64 patients of ESRD slated for RT in the Department of Nephrology and was being followed up during all three visits (pretransplant, three-, and six-month posttransplant). The period of patient recruitment and data collection lasted for approximately 1½ years. Although PWV did not show a significant change, the change in PWV was negatively correlated with baseline PWV, and it was statistically significant. The BRS after RT had a significant improvement as early as three months. The correlation between change in PWV and change in BRS postrenal transplant was not seen. RT improves BRS, but it is still unknown that it is through amelioration of arterial properties or neural components or/and a relative contribution of both. We suggest that the improvement in BRS postrenal transplant is probably because of the improvement in autonomic neural functions rather than the improvement in compliance of barosensitive regions of large arteries.
The present study aims at investigating the nonlinear behavior of single hollow pile in layered soil subjected to varying levels of horizontal dynamic load. A finite element model has been developed ...using commercially available FEM based software. Mohr–Coulomb plasticity model is used to simulate the soil plasticity whereas the pile-material is idealized as elastic. Numerical results are validated comparing with the experimental results. The experimental investigations were carried out in the field located at IIT Kharagpur. Two types of motion: horizontal and rocking are studied. The effects of various influencing parameters, namely, exciting moment, length and diameter of the pile etc. on the nonlinear dynamic response of piles are investigated. It is found that separation of pile from the surrounding soil considerably affects the resonance frequency and amplitude of the pile foundations.
•Two resonant peaks are observed in coupled mode of vibration.•The first resonant amplitude is larger than the second in horizontal mode.•The second resonant amplitude is larger than the first in rocking mode.•Separation between soil and pile results in reduction in stiffness.•Depth of separation is greatly influenced by the second resonant frequency.
This paper presents an investigation of the nonlinear behaviour of single piles subjected to varying levels of vertical dynamic load. A good number of tests are performed for the understanding of the ...dynamic behaviour of single hollow steel piles embedded in layered soil. Experimental results are validated with results obtained from a nonlinear numerical analysis using commercially available Finite Element Method (FEM) based software. The results of numerical analysis and experimental investigations showed that the length of pile has significant influence on resonant frequency and amplitude of the pile foundation. It has also been found that the slippage of pile from the surrounding soil considerably affects the resonance frequency and amplitude of the soil–pile foundation system.
•The length of pile greatly influences resonant frequency and amplitude.•Slippage between soil and pile results in reduction in stiffness of soil–pile system.•Due to slippage the resonant frequency reduces and resonant amplitude increases.•Slippage distance dereases with the depth following a parabolic pattern.
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