Computational Analysis Reveals a Critical Point Mutation in the N-Terminal Region of the Signaling Lymphocytic Activation Molecule Responsible for the Cross-Species Infection with Canine Distemper Virus

Infection of hosts by morbilliviruses is facilitated by the interaction between viral hemagglutinin (H-protein) and the signaling lymphocytic activation molecule (SLAM). Recently, the functional importance of the n-terminal region of human SLAM as a measles virus receptor was demonstrated. However, the functional roles of this region in the infection process by other morbilliviruses and host range determination remain unknown, partly because this region is highly flexible, which has hampered accurate structure determination of this region by X-ray crystallography. In this study, we analyzed the interaction between the H-protein from canine distemper virus (CDV-H) and SLAMs by a computational chemistry approach. Molecular dynamics simulations and fragment molecular orbital analysis demonstrated that the unique His28 in the N-terminal region of SLAM from Macaca is a key determinant that enables the formation of a stable interaction with CDV-H, providing a basis for CDV infection in Macaca. The computational chemistry approach presented should enable the determination of molecular interactions involving regions of proteins that are difficult to predict from crystal structures because of their high flexibility.     

High-throughput characterization of local conductivity of Nd0.9Ca0.1Ba2Cu3O7−δ thin film by the low-temperature scanning microwave microscope

We developed a scanning microwave microscope (SμM) designed for high-throughput electric-property screening as well as for rapid construction of electronic phase diagrams at low temperatures. As a sensor probe, we used a high-Qλ/4 coaxial cavity resonator to which a thin needle with ball-tip end was attached. The sensor module was mounted on the low-temperature XYZ stage, which allowed us to map out the change of resonance frequency and quality factor due to the local tip-sample interaction at low temperatures. From the measurements of combinatorial thin films, such as Ti_1−xCo_xO_2−δ and Nd_0.9Ca_0.1Ba₂Cu₃O_7−δ (NCBCO), it was demonstrated that this SμM system has enough performance for the high-throughput characterization of sample conductance under variable temperature conditions.     

Free-radical-induced polymerization of epoxides in the presence of maleic anhydride

The free-radical-induced reactions of cyclohexene oxide in the presence of maleic anhydride have been found to lead to polyether in presence of AIBN and to a mixture of polyether, ester, and maleic anhydride adduct of polyether with di-tert-butyl peroxide (DTBP), the amounts of the mixture components depending on the concentration of DTBP and the temperature. Analogous reactions in the presence of succinic anhydride lead to no polyether. The obtained polyether has no hydroxyl group. The reaction appears to consist of three different steps, radical initiation, cationic propagation, and radical termination.     

KINETICS OF ENZYMATIC PHOTOREACTIVATION STUDIED WITH PHAGE T1 AND ESCHERZCHZA COLI Bs-1*

Abstract— The kinetics of enzymatic photoreactivation (PR) of u.v.-induced killing was compared among E. coli B_s-1, phage T1 in B_s-1 and phage T1 in irradiated B_s-1. The PR action spectrum showed no substantial difference between PR of B_s-1 and PR of T1 in B_s-1. The PR D₃₇ (i.e. the PR dose required to reactivate all but 37 per cent of the reactivable lethal lesions) was found to decrease linearly with decreasing U.V. dose whether U.V. was given to produce pyrimidine dimers in B_s-1 DNA, which then compete with irradiated T1 DNA for PR enzyme, or to B_s-1 or T1 DNA to produce dimers serving as substrate for the PR enzyme. A generalized Michaelis-Menten formula was used to analyze the data and the following conclusions were drawn. (1) The number of PR enzyme molecules per cell available for PR of T1 DNA inside the B_s-1 host is only a quarter of the number available for PR of the B_s-1 host itself. (2) The Michaelis constant K_m for reaction of host-DNA-damage and PR-enzyme becomes larger when the host damage acts as competitive inhibitor to PR of T1 DNA than when it is the substrate for PR enzyme. (3) PR enzyme retains almost all its initial catalytic efficiency even after about two-hundred rounds of catalytic functioning. Conclusions (1) and (2) suggest that PR enzyme is concentrated within the nuclear area surrounding the host DNA.     

Improved Mutual Separation of Some Metal Ions by Introducing Sulfur Atom in Bis(l,l,3,3-tetramethylbutyl)phosphinic Acid

Hard and Soft Acids and Bases Principle (HSAB Principle) of Pearson, Jensen, Davies and Hartley, which consider a metal ion as a Lewis acid and a monodentate ligand as a Lewis base, had been used to evaluate the interaction between a central metal ion and the donor atom of a ligand.     

Sound propagation in soundproofing casement windows

Casement windows consisted of two wooden frames that can be opened and closed at various angles are widely used in developing countries with tropical climates. However, an annual increase in a number of motorcycles and automobiles and traffic noise level these countries have rendered these windows to be useless. In this paper, we present a model for manufacturing windows which are suitable for the developing tropical countries. These windows are capable of ventilating, regulating sunlight, protecting against coldness, and reducing traffic noise and fumes from motor vehicles. The ventilation and soundproofing unit hold an importance place in the design of the windows and are calculated using the wave equation and observations of higher-order mode waves. In order to maximize the soundproofing ability, the selection of size and placement of input and output openings in such a way that would minimize the effects of higher-order mode waves are considered in details.     

On arithmetical completeness of the logic of proofs

In this paper, we establish a stronger version of Artemov's arithmetical completeness theorem of the Logic of Proofs ${\mathsf{LP}}_0$. Moreover, we prove a version of the uniform arithmetical completeness theorem of ${\mathsf{LP}}_0$.     

Quantum tunneling of magnetization via well-defined Dy–Cu exchange coupling in a ferrimagnetic high-spin [Dy4Cu] single-molecule magnet

A centrosymmetric rectangular complex [Dy₄Cu] was prepared from dysprosium(III) 1,1,1,5,5,5-hexafluoropentane-2,4-dionate and copper(II) dimethylglyoximate. From magnetic studies, the Dy magnetic moments are all aligned parallel at the ground state via antiferromagnetic superexchange interaction with the central Cu spin. In pulsed-field magnetization measurements at 0.5 K, complex [Dy₄Cu] exhibited magnetization steps with hysteresis, which is typical of a single-molecule magnet. This behavior is explained in terms of a simple Ising model together with well-defined Dy–Cu exchange coupling (−0.64 K).     

Silver‐Catalyzed Efficient Synthesis of Oxindoles and Pyrroloindolines via α‐Aminoalkylation of N‐Arylacrylamides with Amino Acid Derivatives

α‐Aminoalkylation of N‐arylacrylamides with amino acid derivatives was achieved by silver‐catalysis in moderate to high yields. The reaction provides an efficient strategy for the synthesis of functionalized oxindoles, and is suitable for a wide range of N‐arylacrylamides and amino acids, both of which are inexpensive and readily available. The oxindoles obtained were readily transformed into densely functionalized pyrroloindolines by deprotection and cyclization in one pot.