1,153 research outputs found
Learning from past failures: Challenges with monoclonal antibody therapies for COVID-19
COVID-19, the disease caused by infection with SARS-CoV-2, requires urgent development of therapeutic interventions. Due to their safety, specificity, and potential for rapid advancement into the clinic, monoclonal antibodies (mAbs) represent a highly promising class of antiviral or anti-inflammatory agents. Herein, by analyzing prior efforts to advance antiviral mAbs for other acute respiratory infections (ARIs), we highlight the challenges faced by mAb-based immunotherapies for COVID-19. We present evidence supporting early intervention immediately following a positive diagnosis via inhaled delivery of mAbs with vibrating mesh nebulizers as a promising approach for the treatment of COVID-19
Elementary excitations in one-dimensional spin-orbital models: neutral and charged solitons and their bound states
We study, both numerically and variationally, the interplay between different
types of elementary excitations in the model of a spin chain with anisotropic
spin-orbit coupling, in the vicinity of the "dimer line" with an exactly known
dimerized ground state. Our variational treatment is found to be in a
qualitative agreement with the exact diagonalization results. Soliton pairs are
shown to be the lowest excitations only in a very narrow region of the phase
diagram near the dimer line, and the phase transitions are always governed by
magnon-type excitations which can be viewed as soliton-antisoliton bound
states. It is shown that when the anisotropy exceeds certain critical value, a
new phase boundary appears. In the doped model on the dimer line, the exact
elementary charge excitation is shown to be a hole bound to a soliton. Bound
states of those "charged solitons" are studied; exact solutions for N-hole
bound states are presented.Comment: 11 pages revtex, 6 figure
X-ray standing wave and reflectometric characterization of multilayer structures
Microstructural characterization of synthetic periodic multilayers by x-ray
standing waves have been presented. It has been shown that the analysis of
multilayers by combined x-ray reflectometry (XRR) and x-ray standing wave (XSW)
techniques can overcome the deficiencies of the individual techniques in
microstructural analysis. While interface roughnesses are more accurately
determined by the XRR technique, layer composition is more accurately
determined by the XSW technique where an element is directly identified by its
characteristic emission. These aspects have been explained with an example of a
20 period Pt/C multilayer. The composition of the C-layers due to Pt
dissolution in the C-layers, PtC, has been determined by the XSW
technique. In the XSW analysis when the whole amount of Pt present in the
C-layers is assumed to be within the broadened interface, it l eads to larger
interface roughness values, inconsistent with those determined by the XRR
technique. Constraining the interface roughness values to those determined by
the XRR technique, requires an additional amount of dissolved Pt in the
C-layers to expl ain the Pt fluorescence yield excited by the standing wave
field. This analysis provides the average composition PtC of the
C-layers .Comment: 12 pages RevTex, 10 eps figures embedde
Electroactive biofilms: new means for electrochemistry
This work demonstrates that electrochemical reactions can be catalysed by the natural biofilms that form on
electrode surfaces dipping into drinking water or compost. In drinking water, oxygen reduction was monitored with
stainless steel ultra-microelectrodes under constant potential electrolysis at )0.30 V/SCE for 13 days. 16 independent experiments were conducted in drinking water, either pure or with the addition of acetate or dextrose. In
most cases, the current increased and reached 1.5–9.5 times the initial current. The current increase was attributed to
biofilm forming on the electrode in a similar way to that has been observed in seawater. Epifluorescence microscopy
showed that the bacteria size and the biofilm morphology depended on the nutrients added, but no quantitative
correlation between biofilm morphology and current was established. In compost, the oxidation process was
investigated using a titanium based electrode under constant polarisation in the range 0.10–0.70 V/SCE. It was
demonstrated that the indigenous micro-organisms were responsible for the current increase observed after a few
days, up to 60 mA m)2. Adding 10 mM acetate to the compost amplified the current density to 145 mA m)2 at 0.50 V/SCE. The study suggests that many natural environments, other than marine sediments, waste waters and
seawaters that have been predominantly investigated until now, may be able to produce electrochemically active
biofilm
Atomic layering at the liquid silicon surface: a first- principles simulation
We simulate the liquid silicon surface with first-principles molecular
dynamics in a slab geometry. We find that the atom-density profile presents a
pronounced layering, similar to those observed in low-temperature liquid metals
like Ga and Hg. The depth-dependent pair correlation function shows that the
effect originates from directional bonding of Si atoms at the surface, and
propagates into the bulk. The layering has no major effects in the electronic
and dynamical properties of the system, that are very similar to those of bulk
liquid Si. To our knowledge, this is the first study of a liquid surface by
first-principles molecular dynamics.Comment: 4 pages, 4 figures, submitted to PR
Probing Ion-Ion and Electron-Ion Correlations in Liquid Metals within the Quantum Hypernetted Chain Approximation
We use the Quantum Hypernetted Chain Approximation (QHNC) to calculate the
ion-ion and electron-ion correlations for liquid metallic Li, Be, Na, Mg, Al,
K, Ca, and Ga. We discuss trends in electron-ion structure factors and radial
distribution functions, and also calculate the free-atom and metallic-atom
form-factors, focusing on how bonding effects affect the interpretation of
X-ray scattering experiments, especially experimental measurements of the
ion-ion structure factor in the liquid metallic phase.Comment: RevTeX, 19 pages, 7 figure
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