Search for large extra dimensions via single photon plus missing energy final states at sqrt s = 1.96 TeV

We report on a search for large extra dimensions in a data sample of approximately 1 fb(-1) of pp[over] collisions at sqrt s=1.96 TeV. We investigate Kaluza-Klein graviton production with a photon and missing transverse energy in the final state. At the 95% C.L. we set limits on the fundamental mass scale M(D) from 884 to 778 GeV for two to eight extra dimensions.     

Search for scalar neutrino superpartners in e+mu final states in pp collisions at sqrt[s]=1.96 TeV

We report a search for R-parity-violating production and decay of sneutrino particles in the emu final state with 1.04+/-0.06 fb-1 of data collected with the D0 detector at the Fermilab Tevatron Collider in 2002-2006. Good agreement between the data and the standard model prediction is observed. With no evidence for new physics, we set limits on the R-parity-violating couplings lambda'311 and lambda312 as a function of the sneutrino mass.     

Search for Randall-Sundrum gravitons with 1 fb(-1) of data from pp collisions at sqrt(s)=1.96 TeV

We search for decays of Kaluza-Klein excitations of the graviton in the Randall-Sundrum model of extra dimensions to e+ e(-) and gamma gamma in 1 fb(-1) of pp collisions at sqrt(s)=1.96 TeV collected by the D0 detector at the Fermilab Tevatron. We set 95% confidence level upper limits on the production cross section times branching fraction, which translate into lower limits on the mass of the lightest excitation between 300 and 900 GeV for values of the coupling k/MPl between 0.01 and 0.1.     

Study of normal ocular thermogram using textural parameters

Ocular surface temperature (OST) has been studied with numerous approach and Infrared (IR) thermography has proved to be the best way to capture temperature distribution over some surfaces. It is applied to a number of biomedical applications including studies in the field of ophthalmology. However, the analysis of an ocular thermogram is largely in nascent stage, and is usually achieved by first-order texture analysis. This current study conducted second-order texture analysis on ocular thermal images, mainly by cross co-occurrence matrix together with first-order texture analysis, moments and difference histogram. It was found that, for subjects aged above 35 years old their interocular difference in median, textural contrast, moment 2 and moment 3 (in absolute value) were significantly higher than younger peers. Several significant linear correlations among investigated features were observed. The features extracted from cross co-occurrence matrix may play an important role in the diagnosis of ocular diseases.     

Determination of palladium by chemical neutron activation analysis using low energy photon spectrometry

A chemical neutron activation analysis method to determine trace amounts of palladium present in the uranium ores has been developed. Palladium was concentrated on an anionic exchanger to purify from large amounts of uranium, iron and copper that were present in the ore. The resin in which Pd was adsorbed was neutron irradiated and the activation product¹⁰⁹Pd was assayed through its daughter^109mAg by low energy photon spectrometry to estimate palladium. Both the 88 keV gamma-line and the 22 keV X-ray line (arising out of the internal transition of^109mAg) were used to arrive at the concentration values by a standard comparison technique. A thin window Si(Li) detector and an HPGe detector were used for the radioactive assay. Detection limits and the advantage of using the X-ray line of Ag over that of the gamma-line were discussed. An absolute detection limit of 0.12·10⁻⁹ g could be arrived at by the use of the 22.10 keV X-ray line in an interference-free condition.     

Inhibitor binding influences the protonation states of histidines in SARS-CoV-2 main protease

The main protease (M^pro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an attractive target for antiviral therapeutics. Recently, many high-resolution apo and inhibitor-bound structures of M^pro, a cysteine protease, have been determined, facilitating structure-based drug design. M^pro plays a central role in the viral life cycle by catalyzing the cleavage of SARS-CoV-2 polyproteins. In addition to the catalytic dyad His41–Cys145, M^pro contains multiple histidines including His163, His164, and His172. The protonation states of these histidines and the catalytic nucleophile Cys145 have been debated in previous studies of SARS-CoV M^pro, but have yet to be investigated for SARS-CoV-2. In this work we have used molecular dynamics simulations to determine the structural stability of SARS-CoV-2 M^pro as a function of the protonation assignments for these residues. We simulated both the apo and inhibitor-bound enzyme and found that the conformational stability of the binding site, bound inhibitors, and the hydrogen bond networks of M^pro are highly sensitive to these assignments. Additionally, the two inhibitors studied, the peptidomimetic N3 and an α-ketoamide, display distinct His41/His164 protonation-state-dependent stabilities. While the apo and the N3-bound systems favored N_δ (HD) and N_ϵ (HE) protonation of His41 and His164, respectively, the α-ketoamide was not stably bound in this state. Our results illustrate the importance of using appropriate histidine protonation states to accurately model the structure and dynamics of SARS-CoV-2 M^pro in both the apo and inhibitor-bound states, a necessary prerequisite for drug-design efforts.

The main protease (M^pro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an attractive target for antiviral therapeutics.     

Positron annihilation studies on radiation‐crosslinked poly(N‐isopropylacrylamide) hydrogels

The temperature‐sensitive poly(N‐isopropylacrylamide) hydrogels, prepared by γ and electron‐beam (EB) irradiation, were studied using positron annihilation lifetime spectroscopy (PALS). The effect of water content in the hydrogel on the ortho‐positronium (o‐Ps) lifetime and intensity was investigated. The observed positronium lifetime suggests microstructural differences between γ‐ and EB‐synthesized hydrogels. The distribution in positronium lifetime indicates nonhomogeneity in the distribution of free‐volume holes in EB‐synthesized hydrogels. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3462–3466, 2000     

Block Copolymer Micelles with Near Infrared Metal Phthalocyanine Dyes for Laser Induced Writing

A route has been developed to disperse metal‐containing phthalocyanine dyes in a non‐polar medium based on amphiphilic block copolymer micelles of poly[styrene‐block‐(4‐vinylpyridine)] (PS‐b‐P4VP) and poly[styrene‐block‐(acrylic acid)] (PS‐b‐PAA) copolymers. Polar P4VP and PAA efficiently encapsulate cobalt(II ), manganese(II ), and nickel(II ) phthalocyanine dyes by axial coordination of nitrogen and µ‐oxo bridged dimerization with the transition metals, respectively. Good dispersion of the dyes is confirmed by the linear enhancement of Q‐bands in UV–vis absorption spectra with dye concentration. A thin monolayered PS‐b‐P4VP micelle film that contained a nickel(II ) phthalocyanine dye which efficiently adsorbs a laser beam on a localized area to generate a local heat higher than the glass transition temperatures of both blocks. One‐dimensional laser writing on the dye‐containing film allows the fabrication of a few submicrometer wide line patterns in which the self‐assembled nanostructure of the block copolymer is modified by the directional heat arising from laser scanning.