Antibacterial cotton fabrics with in situ generated silver and copper bimetallic nanoparticles using red sanders powder extract as reducing agent

Using aqueous extraction of red sanders powder as a reducing agent, silver and copper bimetallic nanoparticles were in situ generated in cotton fabrics. Silver and copper nanoparticles were also generated separately for comparison. The resulted nanocomposite cotton fabrics (NCFs) were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and antibacterial tests. SEM analysis indicated the generation of more number of nanoparticles when bimetallic source solutions were used. Further, the size range of the generated bimetallic nanoparticles was found to be lower than when individual metal nanoparticles were generated in NCFs. XRD analysis confirmed the in situ generation of silver and copper nanoparticles when equimolar bimetallic salt source solutions were utilized. The NCFs with bimetallic nanoparticles exhibited higher antibacterial activity against both Gram-negative and Gram-positive bacteria and hence can be considered for applications as antibacterial bed and dressing materials.     

Investigation of Sequence Clipping and Structural Heterogeneity of an HIV Broadly Neutralizing Antibody by a Comprehensive LC-MS Analysis

CAP256 is one of the highly potent, broadly neutralizing monoclonal antibodies (bNAb) designed for HIV-1 therapy. During the process development of one of the constructs, an unexpected product-related impurity was observed via microfluidics gel electrophoresis. A panel of complementary LC-MS analyses was applied for the comprehensive characterization of CAP256 which included the analysis of the intact and reduced protein, the middle-up approach, and a set of complementary peptide mapping techniques and verification of the disulfide bonds. The designed workflow allowed to identify a clip within a protruding acidic loop in the CDR-H3 region of the heavy chain, which can lead to the decrease of bNAb potency. This characterization explained the origin of the additional species reflected by the reducing gel profile. An intra-loop disulfide bond linking the two fragments was identified, which explained why the non-reducing capillary electrophoresis (CE) profile was not affected. The extensive characterization of CAP256 post-translational modifications was performed to investigate a possible cause of CE profile complexity and to illustrate other structural details related to this molecule’s biological function. Two sites of the engineered Tyr sulfation were verified in the antigen-binding loop, and pyroglutamate formation was used as a tool for monitoring the extent of antibody clipping. Overall, the comprehensive LC-MS study was crucial to (1) identify the impurity as sequence clipping, (2) pinpoint the clipping location and justify its susceptibility relative to the molecular structure, (3) lead to an upstream process optimization to mitigate product quality risk, and (4) ultimately re-engineer the sequence to be clip-resistant.

Open image in new window

Graphical Abstract ?

     

Precision two-photon spectroscopy of alkali elements

In this paper, we have briefly reviewed the work on two-photon spectroscopy of alkali elements and its applications. The technique of Doppler-free two-photon spectroscopy is briefly summarized. A review of various techniques adopted for measuring absolute frequencies of the atomic transitions and precision measurements of isotope shifts and hyperfine structures (HFS) is presented. Some of the recent works on precision measurements of HFS constants of 6s ² S _1/2 level of ³⁹K and ⁴¹K, 9s ² S _1/2level and 7d ² D _3/2 level of ¹³³Cs are also discussed.     

Mixed convection flow in vertical channel with boundary conditions of third kind in presence of heat source/sink

The effects of viscous dissipation and heat source/sink on fully developed mixed convection for the laminar flow in a parallel-plate vertical channel are investigated.The plate exchanges heat with an external fluid.Both conditions of equal and different reference temperatures of the external fluid are considered.First,the simple cases of the negligible Brinkman number or the negligible Grashof number are solved analytically.Then,the combined effects of buoyancy forces and viscous dissipation in the presence of heat source/sink are analyzed by a perturbation series method valid for small values of the perturbation parameter.To relax the conditions on the perturbation parameter,the velocity and temperature fields are solved by using the Runge-Kutta fourth-order method with the shooting technique.The velocity,temperature,skin friction,and Nusselt numbers at the plates are discussed numerically and presented through graphs.     

Generation of 2.1 μm wavelength from degenerate high gray track resistant potassium titanyl phosphate optical parametric oscillator

This paper presents the experimental results of degenerate optical parametric generation using a high gray track resistant potassium titanyl phosphate (HGTR KTP) optical parametric oscillator (OPO). An average output power of 7 W at 10 kHz has been achieved that includes both signal and idler powers near degeneracy using 20 W average power from a 1064 nm Nd:YVO₄ pump source corresponding to an optical conversion efficiency of 35%.     

Neutron detector array at IUAC: Design features and instrumentation developments

The characteristics and performance of the newly commissioned neutron detector array at IUAC are described. The array consists of 100 BC501 liquid scintillators mounted in a semi-spherical geometry and are kept at a distance of 175 cm from the reaction point. Each detector is a 5^″ × 5^″ cylindrical cell coupled to 5^″ diameter photomultiplier tube (PMT). Signal processing is realized using custom-designed home-made integrated electronic modules which perform neutron – gamma discrimination using zero cross timing and time-of-flight (TOF) technique. Compact custom built high voltage power supply developed using DC–DC converters are used to bias the detector. The neutrons are recorded in coincidence with fission fragments which are detected using multi-wire proportional counters mounted inside a 1 m diameter SS target chamber. The detectors and electronics have been tested off-line using radioactive sources and the results are presented.     

Numerical Algorithm Based on Quintic Nonpolynomial Spline for Solving Third-Order Boundary Value Problems Associated with Draining and Coating Flows

A numerical algorithm is developed for the approximation of the solution to certain boundary value problems involving the third-order ordinary differential equation associated with draining and coating flows. The authors show that the approximate solutions obtained by the numerical algorithm developed by using nonpolynomial quintic spline functions are better than those produced by other spline and domain decomposition methods. The algorithm is tested on two problems associated with draining and coating flows to demonstrate the practical usefulness of the approach.     

Main injector particle production experiment at Fermilab

The main injector particle production (MIPP) experiment at Fermilab uses particle beams of charged pions, kaons, proton and antiproton with beam momenta of 5?C90 GeV/c to measure particle production cross-sections of various nuclei including liquid hydrogen, MINOS target and thin targets of beryllium, carbon, bismuth and uranium. The physics motivation to perform such cross-section measurements is described here. Recent results on the analysis of NuMI target and forward neutron cross-sections are presented here. Preliminary cross-section measurements for 58 GeV/c proton on liquid hydrogen target are also presented. A new method is described to correct for low multiplicity inefficiencies in the trigger using KNO scaling.