Determination of Allosteric Effects and Interstrand Bidentate Interactions in DNA‐Peptide Molecular Recognition

To study DNA allostery, quantitative DNase I footprinting studies were carried out on a newly designed peptide His‐Hyp‐Lys‐Lys‐(Py)₄‐Lys‐Lys‐NH₂ (HypKK‐10) containing the XHypKK (Hyp = hydroxyproline) and polyamide motifs. The interconnection of DNA footprints of peptides HypKK‐10 and the parent peptide PyPro‐12 supports the proposal that interaction network cooperativity is preferred in DNA‐peptide interactions between multiple recognition sites. A simple method of determining interstrand bidentate interactions between the peptide moieties and DNA bases is introduced. It is envisaged that interstrand bidentate interactions also participate in the relay of conformational changes to recognition sites on the complementary strands. Circular dichroism studies of the titration of peptide HypKK‐10 with an oligonucleotide duplex indicate that this peptide binds in a dimeric fashion to DNA in the minor groove. This work may prompt the design of new DNA binding ligands for the study of DNA‐peptide allosteric interactions and DNA interaction network.     

Synthesis and characterization of chemically anchored adenosine with PHEMA grafted gold nanoparticles

The synthesis of chemically anchored adenosine with biocompatible poly(2-hydroxylethyl methacrylate) grafted gold nanoparticles (Ado-i-PHEMA-g-AuNPs) was realized by employing a simple strategy. Disulfide-containing poly(2-hydroxylethyl methacrylate) (DT-PHEMA) was initially synthesized by atom transfer radical polymerization (ATRP). The formation of DT-PHEMA was confirmed by ¹H-NMR and FT-IR. The molecular weight and molecular weight distribution were found to be 9.6 kg/mol and 1.40 from GPC analysis. DT-PHEMA was subsequently used for the synthesis of PHEMA-g-AuNPs by a grafting to protocol. The grafting of DT-PHEMA on the surface of AuNPs was confirmed by FT-IR, TGA, XPS, and EDX analyses. The particle size of the PHEMA-g-AuNPs was found to be ca. 5.0 nm from HR-TEM analysis. Boronic acid was used for functionalization of PHEMA-g-AuNPs, which was then subjected for covalent immobilization with adenosine via strong interaction between free hydroxyl groups of adenosine and boronic acid. Characterization and properties of the Ado-i-PHEMA-g-AuNPs were investigated by taking advantage from FT-IR, XPS, EDX, and UV-visible spectroscopy. The Ado-i-PHEMA-g-AuNPs nanocomposite exhibits a surface plasmon resonance peak at 586 nm which is red shifted from AuNPs (521 nm), indicating significant changes of surface property upon PHEMA-adenosine immobilization onto the surface of AuNPs.     

Plasma Characteristics of Internal Inductively Coupled Plasma Source with Ferrite Module

Electrical and plasma properties of a U-shaped internal inductively coupled plasma (ICP) source with/without a Ni-Zn ferrite module installed above the ICP antenna were investigated. By installing the ferrite module on the antenna, the increase of plasma density and the decrease of plasma potential could be observed. The increase of plasma density was related to the efficient inductive coupling to the plasma by concentrating the induced magnetic field between the antenna and the substrate. At 800 W of ICP power and 20mTorr Ar, a high density plasma on the order of 4.5′10¹¹/cm³ could be obtained.     

Risk in Inventory Models: The Case of the Newsboy Problem — Optimality Conditions

A recent article in this journal employs the capital-asset pricing model for the analysis of the newsboy problem and shows how the covariance risk affects the optimal inventory policy. The purpose of this paper is to sharpen the optimality conditions given by the article and hence to provide a simple method for finding the solution. Under reasonable assumptions, this paper shows that the optimal ordering policy can be described by a single equation, regardless of the sign of the covariance term.     

Asymmetric borane reduction of achiral ketones mediated by a chiral oxazaborolidine derived from (−)-ephedrine

Asymmetric borane reduction of achiral ketones in the presence of a chiral oxazaborolidine derived from (−)-ephedrine yielded the corresponding alcohols in optical yields of 41 – 83 % ee.     

Exact self-gravitating N-body motion in the CGHS model

In the asymptotically flat two-dimensional dilaton gravity, we present an N-body particle action which has a dilaton coupled mass term for the exact solubility. This gives nonperturbative exact solutions for the N-body self-gravitating system, so the infalling particles form a black hole and their trajectories are exactly described. In our two-dimensional case, the critical mass for the formation of black holes does not exist, so even a single particle forms a black hole. The infalling particles give additional time-like singularities in addition to the space-like black hole singularity. However, the latter singularities can be properly cloaked by the future horizons within some conditions.     

Surface chemkin: A general formalism and software for analyzing heterogeneous chemical kinetics at a gas-surface interface

This article describes a general kinetic formalism for treating the details of heterogeneous reactions at a gas-solid interface. We develop a nomenclature for treating reactions between the gas phase and surface species residing on any number of surface site types and bulk-phase species residing in bulk-phase mixtures or in pure bulk phases. The rate of progress of surface reactions follows the law of mass-action. We discuss the relationship between macroscopic conservation laws for mass and energy and the microscopic surface reaction rates as they might appear in boundary conditions for a chemically reacting flow. The formalism developed has been implemented in a general package of Fortran computer codes for the evaluation of complex surface-reaction kinetics called Surface Chemkin.