Geometry of Hasimoto Surfaces in Minkowski 3-Space

In this paper, we investigate the Hasimoto surfaces in Minkowski 3-space. We discussed the geometric properties of Hasimoto surfaces in \(\mathbb {M}^{3}\) for three cases. The Gaussian and mean curvature of Hasimoto surface are found for each case. Then, we give the characterization of parameter curves of Hasimoto surfaces in \(\mathbb {M}^{3}.\)      

Simple Stereocontrolled Synthesis of Methyl 2-Deoxy-d-erythro-hexopyranosid-4-uloses,Thromboxane B2 (TXB2) Precursors,from d-Galactose

Abstract

The stereospecific synthesis of methyl 3-O-benzoyl-6-O-(tert-butyldiphenylsilyl)-2-deoxy-α-d-erythro-hexopyranosid-4-ulose (5) - a Thromboxane B₂ (TXB₂) precursor -starting from D-galactose is described. Facile and established methods including selective benzoylation, oxidation-elimination and a stereocontrolled hydrogenation (Pd/charcoal) were employed effectively.     

Bare Histidine–Serine Models: Implication and Impact of Hydrogen Bonding on Nucleophilicity

A new family of 2‐hydroxyalk(en/yn)ylimidazoles has been evaluated as serine–histidine bare dyad models for the ring‐opening reaction of L ‐lacOCA, a cyclic O‐carboxyanhydride. These models were selected to unravel the implication of intramolecular hydrogen bonding and to substantiate its influence on the nucleophilicity of the alcohol moiety, as it is suspected to occur in enzyme active sites. Although designed to exclusively facilitate the preliminary step of proton transfer during the studied ring‐opening reaction, these minimalistic models depicted a measureable increase in reactivity relative to the isolated fragments. A couple of reliable experimental and theoretical methods have been developed to readily monitor the strength of the intramolecular hydrogen bond in dilute solution. Results show that the folded conformers are the most nucleophilic species because of the intramolecular hydrogen bond.     

Cure Characterization of a New Bismaleimide Resin using Differential Scanning Calorimetry

The cure characterization of a new BMI resin was investigated to ascertain a suitable cure model for the material. A series of isothermal differential scanning calorimetry (DSC) runs from 170°C to 220°C provided information about the cure characterization. All “kinetic triplet” (i. e., Arrhenius parameters A, activation energy E, and the reaction model, f(α)) of this new BMI system were calculated. It was found that the cure characterization of this new BMI could be expressed by nth‐order cure reaction.     

Disentangling effects of nuclear structure in heavy element formation

Forming the same heavy compound nucleus with different isotopes of the projectile and target elements allows nuclear structure effects in the entrance channel (resulting in static deformation) and in the dinuclear system to be disentangled. Using three isotopes of Ti and W, forming 232Cm, with measurement spanning the capture barrier energies, alignment of the heavy prolate deformed nucleus is shown to be the main reason for the broadening of the mass distribution of the quasifission fragments as the beam energy is reduced. The complex, consistently evolving mass-angle correlations that are observed carry more information than the integrated mass or angular distributions, and should severely test models of quasifission.     

Synthesis of magnetic core–shell Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>–Au nanoparticle for biomolecule immobilization and detection

The production of monodispersed magnetic nanoparticles with appropriate surface modification has attracted increasing attention in biomedical applications including drug delivery, separation, and purification of biomolecules from the matrices. In the present study, we report rapid and room temperature reaction synthesis of gold-coated iron nanoparticles in aqueous solution using the borohydride reduction of HAuCl₄ under sonication for the first time. The resulting nanoparticles were characterized with transmission electron microscopy (TEM), electron spectroscopy for chemical analysis (ESCA), ultraviolet visible spectroscopy (UV–Vis), and X-ray diffraction (XRD). Surface charges and magnetic properties of the nanoparticles were also examined. The pattern of Fe₃O₄ nanoparticles is face centered cubic with an average diameter of 9.5 nm and the initial reduction of gold on the surface of Fe₃O₄ particles exhibits uniform Fe₃O₄–Au nanoparticles with an average diameter of 12.5 nm. The saturation magnetization values for the uncoated and gold-coated Fe₃O₄ nanoparticles were found to be 30 and 4.5 emu/g, respectively, at 300 K. The progression of binding events between boronic acid terminated ligand shell and fructose based on the covalent bonding interaction was measured by absorbance spectral changes. Immunomagnetic separation was also performed at different E. coli concentration to evaluate capturing efficiency of resulting nanoparticles. Immunomagnetic separation percentages were varied in a range of 52.1 and 21.9% depend on the initial bacteria counts.