Synthesis and Characterization of Yttrium Doped Nano-zirconia by a Cationic Surfactant-assisted Route

1INTRODUCTION Zirconia is a kind of metal oxide material with high melting point(2700℃),high boiling point,small thermal conductivity,large coefficient of ther-mal expansion,high temperature resistance,good abrasive resistance and favorable resistance to corrosion.Due to its both acid and alkaline surface centers,zirconia is an ideal catalytic material with acid group bi-functions[1].In addition,owing to the excellent ionic exchange property as well as the chemical and mechanical stabilit…     

Synthetic study on neoponkoranol and its side chain epimer as potent α-glucosidase inhibitors,optimization of protecting group

Coupling reaction between thiosugar and triflate as the key protocol to synthesize neoponkoranol, a naturally occurring potent α-glucosidase inhibitor, and its related sulfonium salts was optimized by applying different esters as protecting group, with the yields of desired products being greatly improved. Our proposed mechanism of the coupling reaction indicated that the nucleophilicity of C3-hydroxyl moiety on monosaccharide structure is closely related to the reaction mode.     

Numerical simulation and structure optimization of a liquid–vapor separation plate condenser

Journal of Thermal Analysis and Calorimetry - Based on innovative design, a liquid–vapor separation plate condenser with excellent heat transfer performance is invented. It takes less time to...     

Discovery of a potent and highly β1 specific proteasome inhibitor from a focused library of urea-containing peptide vinyl sulfones and peptide epoxyketones

Syringolins, a class of natural products, potently and selectively inhibit the proteasome and show promising antitumour activity. To gain insight in the mode of action of syringolins, the ureido structural element present in syringolins is incorporated in oligopeptide vinyl sulfones and peptide epoxyketones yielding a focused library of potent new proteasome inhibitors. The distance of the ureido linkage with respect to the electrophilic trap strongly influences subunit selectivity within the proteasome. Compounds 13 and 15 are β5 selective and their potency exceeds that of syringolin A. In contrast, 5 may well be the most potent β1 selective compound active in living cells reported to date.     

Controlled Synthesis and Electrochemical Behavior of Single-crystal MoO2 Nanowhiskers by a Facile Precursor-reduction Route

Among the transition-metal oxides, molybdenum oxides are the focus of much attention owing to its numerous applications in catalysts, additives, sensors, photochromic and electrochromic materials1. Especially, the applications of MoO2 in optical propertie…     

Selective Synthesis of a Hexagonal Co(Ⅱ)-Substituted Sodium Zincophosphate via a Simple and Novel Route

A simple and novel route was provided for the preparation of the hexagonal Co(II)‐substituted sodium zincophosphate (CoZnPO‐HEX), which was obtained with ZnSO₄·7H₂O, CoCl₂·6H₂O and Na₃PO₄·12H₂O as raw materials and polyethylene glycol‐400 (PEG‐400) as a surfactant via a one‐step solid‐state reaction at low heating temperature (60°C), and characterized with X‐ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectra, thermogravimetric analysis and the 1st derivative of thermogravimetric analysis (TG/DTG) and transmission electron microscopy (TEM). The experimental results showed that the CoZnPO‐HEX was selectively formed via this reaction at ambient temperature in the presence of PEG‐400.     

5-epi-Deoxyrhamnojirimycin is a potent inhibitor of an α-l-rhamnosidase: 5-epi-deoxymannojirimycin is not a potent inhibitor of an α-d-mannosidase

Whereas deoxyrhamnojirimycin (LRJ) 1 shows no significant inhibition of naringinase (an α-l-rhamnosidase), its C-5 epimer 2 is a potent and specific inhibitor of the enzyme and demonstrates the value of unambiguous chemical synthesis of such materials in the evaluation of their biological properties. In contrast, moderately weak inhibition towards an α-d-mannosidase is shown by both deoxymannojirimycin (DMJ) 5 and its C-5 epimer 6. Mimics of l-rhamnose which are recognised by enzymes that synthesise or process l-rhamnose may inhibit either the biosynthesis of the sugar or its incorporation into mycobacterial cell walls, providing new strategies for the treatment of diseases such as tuberculosis and leprosy. Molecular modelling studies provide a rationale for the surprisingly potent activity of the C-5 epimer 2 compared with LRJ 1 and support a general hypothesis that potent piperidine glycosidase inhibitors mimic the ⁴H₃ conformation of the relevant glycopyranosyl cation intermediate.     

One‐Pot Synthetic Route to a Class of Polydental Pyridylphosphines

Abstract

A one‐pot synthetic route is presented for convenient preparation of di‐2‐pyridylphenylphosphine (Py₂PPh, 1), di[(2‐pyridyl)phenylphosphino]methane (DPyPM, 2), and two new, long‐chain polydental pyridylphosphines: di[2‐(6‐diphenylphosphino)pyridyl]phenylphosphine (P₃N₂, 3) and bis[2‐(6‐diphenylphosphinopyridyl)phenylphosphino]methane (P₄N₂, 4).     

Investigation of acid–base and surface characteristics of a thermotropic semifluorinated salicylaldimine liquid crystal by inverse gas chromatography

The surface energy of a semifluorinated salicylaldimine liquid crystal has been characterised by inverse gas chromatography over the temperature range 303 to 323 K using n-alkanes, tetrahydrofurane, dichloromethane, chloroform, acetone and ethyl acetate molecular probes. The dispersive component of the surface free energy of the adsorbent surface studied was calculated according to the approaches of Fowkes and Dorris–Gray in the infinite dilution region. The specific free energy, enthalpy and entropy of adsorption of polar probes on the liquid crystal were determined. The values of the specific enthalpy of adsorption were correlated with both the donor and the acceptor numbers of the probes to quantify the acidic and the basic parameters of the liquid crystal surface. The surface of the semifluorinated salicylaldimine liquid crystal was found to show a basic nature, which determined the nature of its interaction with the polar probes.     

Identification of γ-AApeptides with potent and broad-spectrum antimicrobial activity

We report the identification of a new class of antimicrobial peptidomimetics-γ-AApeptides with potent and broad-spectrum activity, including clinically-relevant strains that are unresponsive to most antibiotics. They are also not prone to select for drug-resistance.     

A Regio- and Stereo-Selective Synthesis of a Monoter-Pene-α-Methylene-γ-Butyrolactone

In our synthetic work on the transformation of simple p-menthane monoterpenes, readily available from Brazilian essential oils, into biologically active sesquiterpene lactones, we have prepared the model lactone 4 from p-menth-8-ene 1.¹ The key step in this sequence is a lead tetra-acetate (LTA) oxidative cyclisation² of the 1,3 diol 2 into the tetrahydrofuran 3. The final product is the cis fused lactone 4, isolated as two epimers about the methyl group.     

Synthesis of the highly potent prostanoid FP receptor agonist, AFP-168: a novel 15-deoxy-15,15-difluoroprostaglandin F2α derivative

A novel 15-deoxy-15,15-difluoro-prostaglandin(PG)F_2α derivative 6 (AFP-168) has been synthesized from the Corey aldehyde in six steps. A key aspect of this route is difluorination of an enone and a stereoselective Wittig reaction. The compound shows high affinity to the FP receptor and potent activities for an anti-glaucoma agent.     

Geometry optimization and electronic structures of molecules H_3AXAH_3

The geometries of molecules H_3AXAH_3(X=O,S,Se and A=C,Si)have been optimizedusing STO-3G ab initio calculations and gradient method and the results are in good agreement withreported experimental values.From the STO-3G optimized geometries,we have also calculated theelectronic structures of these molecules using 4-31G and 6-31G basis sets to obtain the MO energies.atomic net charges and dipole moments.The ionization potentials calculated by 6-31G basis set are ingood agreement with experimental values.     

New Route to Synthesis and QSAR Study of 1,2,4‐Aryl Substituted Triazoles

Abstract

Several substituted 1,2,4‐triazoles have been synthesized by a new route and characterized by IR, NMR, mass spectral, and x‐ray diffraction studies. The computer programme PASS for the prediction of biological activities established that these compounds are potential candidates for the screening.     

A uniform molecular model of δ opioid agonist and antagonist pharmacophore conformations

On the basis of a model of the pharmacophore conformations of agonist of the -opioid receptor the corresponding -antagonist conformations were determined by means of force field calculations. The results explain the unusual behavior of several cyclic -casomorphin analogues on the molecular level. Thus, for instance, the model helps to understand why Tyr-c[D-Orn-2-Nal-D-Pro-Gly] is a mixed -agonist and -antagonist. Furthermore, the model is consistent with low energy conformations of other -antagonists such as Tyr-Tic-Phe, Tyr-Tic-Phe-Phe, naltrindole and BNTX. The occupation of a special spatial area by bulky groups close to the protonated N-terminus of opioid peptides is assumed to be highly critical for the switch from agonist to antagonist behavior.     

Is Genetic Engineering a Route to Enhance Microalgae-Mediated Bioremediation of Heavy Metal-Containing Effluents?

Contamination of the biosphere by heavy metals has been rising, due to accelerated anthropogenic activities, and is nowadays, a matter of serious global concern. Removal of such inorganic pollutants from aquatic environments via biological processes has earned great popularity, for its cost-effectiveness and high efficiency, compared to conventional physicochemical methods. Among candidate organisms, microalgae offer several competitive advantages; phycoremediation has even been claimed as the next generation of wastewater treatment technologies. Furthermore, integration of microalgae-mediated wastewater treatment and bioenergy production adds favorably to the economic feasibility of the former process—with energy security coming along with environmental sustainability. However, poor biomass productivity under abiotic stress conditions has hindered the large-scale deployment of microalgae. Recent advances encompassing molecular tools for genome editing, together with the advent of multiomics technologies and computational approaches, have permitted the design of tailor-made microalgal cell factories, which encompass multiple beneficial traits, while circumventing those associated with the bioaccumulation of unfavorable chemicals. Previous studies unfolded several routes through which genetic engineering-mediated improvements appear feasible (encompassing sequestration/uptake capacity and specificity for heavy metals); they can be categorized as metal transportation, chelation, or biotransformation, with regulation of metal- and oxidative stress response, as well as cell surface engineering playing a crucial role therein. This review covers the state-of-the-art metal stress mitigation mechanisms prevalent in microalgae, and discusses putative and tested metabolic engineering approaches, aimed at further improvement of those biological processes. Finally, current research gaps and future prospects arising from use of transgenic microalgae for heavy metal phycoremediation are reviewed.     

RCAI-56, a carbocyclic analogue of KRN7000: its synthesis and potent activity for natural killer (NK) T cells to preferentially produce interferon-γ

RCAI-56 (3), a carbocyclic analogue of KRN7000 (1) was synthesized through an efficient coupling of a carba-α-d-galactose derivative 11 with cyclic sulfamidate derivative 13 of phytosphingosine to give 15. Carbasugar derivative 11 was prepared by starting from methyl α-d-galactopyranoside (4), employing Pd(II)-catalyzed Ferrier rearrangement as the key step. RCAI-56 (3) is a potent stimulant of NKT cells in vivo to induce the production of Th1 biased cytokines such as interferon-γ in mice. According to the docking model of CD1d-3 complex, its stabilization energy is approximately at the same level as that of the CD1d-1 complex.