Ionic peptide aggregation: exploration of conformational dynamics in aqueous solution by computational techniques

The effects of end groups on KEK peptide conformational characteristics and self-assembling properties in water solution are investigated by using long lasting all-atom molecular dynamics simulations. The analysis of the structural macroscopic and microscopic properties and the examination of intra- and intermolecular interactions suggest, in agreement with experimental observations, the role played by side chains and terminal regions in determining the characteristic features of the assemblages. Competition between intra- and interchain interactions greatly affects the diffusivity of peptide molecules and the conformational space that they can sample, ultimately controlling the shape, size, and distribution of the aggregate configurations. Different peptide end groups influence peptide flexibility and seem to play a crucial role in determining the aggregates' supramolecular architectures.     

Myoglobin Detection: Utilizing Functional Magnetic Hybrid and Silica Micro Particles and Simple Molding Based Micro Channel Fabrication

A magnetic separator attached in a zig zag flow channel assembly has been fabricated to detect myoglobin on the micro particles. An anti‐myoglobin conjugated magnetic hybrid and myoglobin conjugated silica micro particles were prepared and used for myoglobin detection on channel. For the detections, the competitive assay principle was followed based on affinity interaction of anti‐myoglobin‐myoglobin. The caliberation curve was plotted based on the deposit percentage of myoglobin conjugated silica micro particles. The calibration curve of the myoglobin showed the linear range between 1 × 10^?8 ‐ 5 × 10^?11 (M) (R² = 0.9944). The minimum detectable concentration was 300 pg/mL. Hence all that concludes that, the application of zig zag flow channel with magnetic separator has offered new, simple and rapid approach for detecting myoglobin in whole blood samples with in 30 min.     

One‐Pot Synthesis of 13‐Acetyl‐9‐methyl‐11‐oxo(or thioxo)‐8‐oxa‐10,12‐diazatricyclo[7.3.1.02,7]trideca‐2,4,6‐trienes under Microwave Irradiation

Oxygen‐bridged monastrol analogs, 13‐acetyl‐9‐methyl‐11‐oxo(or thioxo)‐8‐oxa‐10,12‐diazatricyclo[7.3. 1.0^2,7]trideca‐2,4,6‐trienes, were synthesized by one‐pot three component condensation reaction of substituted salicylaldehyde, acetylacetone and urea or thiourea with nontoxic, inexpensive, and easily available NaHSO₄ as catalyst under microwave irradiation and solvent‐free conditions in short time with good yields. The structures of the products were characterized by IR, ¹H NMR, ¹³C NMR spectra, and elemental analyses.     

Exploiting the high-affinity phosphonate–hydroxyapatite nanoparticle interaction for delivery of radiation and drugs

Hydroxyapatite is biocompatible and used in various biomedical applications. Here, we generated hydroxyapatite nanoparticles (HNPs) of various sizes (40–200 nm) and demonstrated that they can be stably loaded with drugs or radioisotopes by exploiting the high-affinity HA–(poly)phosphonate interaction. Clinically available phosphonates, clodronate, and Tc-99m-methylene-diphosphonate (Tc-99m-MDP), were efficiently loaded onto HNPs within 15 min. Biodistribution of radiolabeled HNP-MDP-Tc99m in mice was monitored non-invasively using microSPECT-CT. Imaging and dosimetry studies indicated that the HNPs, regardless of size, were quickly taken up by Kupffer cells in the liver after systemic administration into mice. Clodronate loaded onto HNPs remained biologically active and were able to result in selective depletion of Kupffer cells. This method of drug or isotope loading on HA is fast and easy as it eliminates the need for additional surface modifications of the nanoparticles.     

Shakedown Analysis of Nonsandwich Structures*

This paper presents a simple method of evaluating the alternating plasticity limit of structures with nonsandwich cross sections under combined stresses. Mathematical programming and matrix formulations are used. A procedure that enables the actual shakedown limit of the nonsandwich structure to be found is then given. Illustrative numerical examples are presented.     

Formation of free radicals during the oxidation of N-methylhydroxyurea with dioxovanadium(V) ions

Unlike the oxidation of hydroxyurea with dioxovanadium(V) ions, which proceeds through the formation of a single free radical, oxidation of N-methylhydroxyurea is characterized by consecutive formation of two oxygen-based free radicals, as recorded by EPR spectroscopy. Although the consumption of overall five V(V) ions per N-methylhydroxyurea molecule has been determined, the formation of NO, or was not observed. These results are in accordance with a previous suggestion that nitric oxide transfer requires an unsubstituted acylhydroxylamine group.     

添加Ru的Mo/HZSM-5催化体系上的甲烷无氧脱氢芳构化

研究了在Ｍｏ／ＨＺＳＭ５催化剂中添加过渡金属阳离子以改变催化剂的反应性能，提高甲烷无氧脱氢芳构化的反应活性和稳定性．在添加第二组分的催化剂中，ＭｏＲｕ／ＨＺＳＭ５具有最佳的反应活性和稳定性．Ｒｕ的加入使甲烷的转化率由原来的６％～７％提高到９８％．采用比表面积及孔分布测定，Ｘ射线衍射，程序升温还原，程序升温氨脱附和差热分析等表征方法研究了ＭｏＲｕ／ＨＺＳＭ５催化剂的物理化学性质．结果表明，Ｒｕ的加入引起Ｍｏ／ＨＺＳＭ５催化剂强酸酸量的下降，并促进了Ｍｏ物种的还原．     

Evaluation and optimization of synthetic routes from dihydroartemisinin to the alkylamino-artemisinins artemiside and artemisone: A test of N-glycosylation methodologies on a lipophilic peroxide

10-Alkylamino-artemisinins including artemiside and artemisone display enhanced activities against malaria. Earlier, dihydroartemisinin (DHA) TMS ether was converted by trimethylsilyl bromide into the 10-β-bromide that with amine nucleophiles provided the amino-artemisinins. In an attempt to develop more economic approaches, direct N-glycosylation of DHA was examined but 2-deoxyartemisinin was invariably obtained. However, hydroxyl group activation by conversion into the 10β-halide in non-polar solvents with anhydrous HCl and Group I and II metal halides, oxalyl chloride or thionyl chloride with catalytic DMSO, and oxalyl bromide did succeed. The β-halides were converted in situ by thiomorpholine into artemiside, and by thiomorpholine-1,1-dioxide into artemisone respectively in scalable reactions. Hydrogen peroxide-acetonitrile or the urea-hydrogen peroxide complex efficiently oxidized the sulfide artemiside to the sulfone artemisone. Overall, a generalized approach to 10-alkylamino-artemisinins is now available.     

On the question of self-trapping of positrons in indium

The Doppler-broadening of the positron annihilation line in 5N indium has been studied over the temperature range 77 K to 427 K. No evidence for self-trapping has been discovered; rather, the prevacancy rise in the F-parameter appears linear. The best value for E_V is 0.59±0.03 eV.