Synthetic Potential of Fucosyltransferase III for the Synthesis of Fluorescent‐labeled Milk Oligosaccharides

Various fundamental biologic roles of milk oligosaccharides have been recognized; however, their structure‐affinity relationship is still not fully revealed. Herein, we describe the synthesis of the fluorescent‐labeled milk oligosaccharides 3‐(5‐dimethylaminonaphthalene‐1‐sulfonylamino)propyl β‐D‐galactopyranosyl‐(1→3)‐[α‐L‐fucopyranosyl‐(1→4)]‐2‐acetamido‐2‐deoxy‐β‐D‐glucopyranoside (1) and 3‐(5‐dimethylamino‐naphthalene‐1‐sulfonylamino)propyl β‐D‐galactopyranosyl‐(1→3)‐[α‐L‐fucopyranosyl‐(1→4)]‐β‐D-glucopyranoside (2) as useful tools for synthetic, analytic, and biologic applications. For the fucosylation of lactose and lacto‐N‐biose, the chemical and the enzymatic syntheses using fucosyltransferase III were compared.     

Reactivite Des α -Phosphonylketones Dans la Reaction de Gewald: Synthese de Nouveaux Derives de L′aminophosphonothiophene

The reaction of α -phosphonylketones 1 with active methylenenitriles 2 leads to phosphonoalkylidenes 3 . The reaction of compounds 3 with sulfur under basic conditions leads to the new 2-amino-4-phosphonothiophenes 4 . The structure of all obtained products was confirmed by NMR (¹H, ³¹P, ¹³C) and IR spectroscopy, and in some cases by mass spectrometry.     

A Selective Removal of Benzyl Protecting Groups in Arylphosphate Esters with Bromotrimethylsilane

Bromotrimethylsilane (BTMS) is shown to be an effectively selective reagent for the debenzylation of dibenzyl arylphosphate esters to give the corresponding arylphosphate acids and does not affect other functional groups also present in the molecular structure.     

Effects of Electron Beam Irradiation on the Structural Properties of PVA/PAM/CMC Ternary Polymer Blends

Ternary miscible blends based on various ratios of poly(vinyl alcohol) (PVA), poly(acrylamide) (PAM) and carboxymethyl cellulose (CMC) were prepared by solution casting in the form of thin films. The structure‐property behavior of the ternary PVA/PAM/CMC blends, before and after they had been exposed to various doses of electron beam irradiation, was investigated by FT‐IR spectroscopy, SEM, XRD and stress‐strain curves. The visual observation showed that the cast films of the individual polymers PVA, PAM, and CMC and their blends over a wide range of composition are clear and transparent indicating the miscibility of PVA/PAM/CMC ternary blends. The FT‐IR analysis of pure polymers or their ternary blends before or after electron beam irradiation proved the formation of hydrogen bonding. In addition, it was found that the intensity of the different absorption bands depends on the ratio of PAM and CMC in the ternary blend. The XRD patterns showed that the peak position for the ternary blends decreases with increasing the ratio of CMC in the blend. However, the peak position for the ternary blend based on equal ratios of pure polymers was not affected by blending and was found in the same position as in the XRD pattern of pure PVA. The SEM micrographs give support to the visual observation indicating the complete miscibility of PVA/PAM/CMC ternary blends. The improvement in morphology leads to improvement in the tensile mechanical properties of the ternary polymer blends.     

Synthesis and antimicrobial activity of some heterocyclic 2,6‐bis(substituted)‐1,3,4‐thiadiazolo‐, oxadiazolo‐, and oxathiazolidino‐pyridine derivatives from 2,6‐pyridine dicarboxylic acid dihydrazide

In this work, we report on the synthesis and preliminary biological activity screening of several heterocyclic derivatives 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 10a , 10b , 11 , 11a , 11b , 12 , 12a , 12b , 13 , 13a , 13b , 14 , 15 based on N2′,N6′‐diphenylthiosemi‐carbazide pyridine‐2,6‐dicarbohydrazide 2 , which has been obtained from the corresponding dihydrazide 1 . The biological screening showed that many of these compounds have good antimicrobial activities. The structure of the new compounds has been established on the bases of chemical and spectroscopic evidences. J. Heterocyclic Chem., (2011).     

EDXRF,FTIR, and XRD characterization of low calcium oxalate urinary stones collected from arid area

Low calcium oxalate urinary stones from the kidney, bladder, and ureter have been collected from the arid area (Taif, Saudi Arabia). After careful washing and drying of the collected stones, the samples were converted into a contamination-free homogenous fine powder with a particles' size smaller than 50 μm. The processed urinary stone powders were studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), laboratory setup and synchrotron radiation X-ray diffraction (XRD), and energy-dispersive X-ray fluorescence (EDXRF). The activated function groups, quantitative phase analysis, and the semi-quantitative elemental analysis of the present urinary stones were identified. Seventeen elements were measured in most of the urinary stone samples. The significant elements are Ca, P, S, Cl, Zn, K, Fe, and Cu, whereas other elements were found alternatively in a few number of urinary stone samples. It was recognized that Ca exists with low concentration, which indicates the presence of different calcium phases even with low percentages. In 33% of the urinary stones, the phosphorus (P) was not measured, but there were high concentrations of sulfur (S) and low concentrations of Ca up to 2.15 ± 0.05%. The ATR-FTIR results indicate that the most compounds of the present urinary stones were urea and cystine combined with low ratios of calcium oxalate and calcium phosphate compounds. The quantitative phase analysis of the XRD of selected samples proves the presence of the cystine, urea, and calcium oxalate phases with different weight percent.     

Theoretical analysis of the electronic,optical and thermal properties of lead strontium telluride alloys Pb1−xSrxTe (x = 0.0−1.0)

We have simulated different physical properties of Pb_1?xSr_xTe semiconductors, using the Ab-initio full potential augmented plane wave (FP-LAPW) method. The two commonly used exchange potentials viz., PBE-GGA and WC-GGA are used along with the most recently developed modified Becke and Johnson (mBJ) potential to study the electronic and optical properties. In this study, we have observed an increase in band gap values as well as the lattice parameter with increasing the concentration of Sr atoms in Pb_1?xSr_xTe alloys while the bulk modulus and the refractive index have reverse effect. The microscopic origin of the band gap bowing is explained using the approach of Zunger and co-workers. At ambient conditions (p = 0, T = 0), the calculations indicate that Pb_1?xSr_xTe is a direct band gap semiconductor R–R with x = 0.125, 0.25, 0.375, 0.5, 0.625, 0.75 and 0.875. The refractive indices are also calculated using the FP-LAPW method and the models of Moss, Ravindra and the Herve–Vandame. The obtained results are in consistent with the previous available data. To study the thermal effects, the temperature effect on the lattice parameters, thermal expansions, heat capacities the quasi-harmonic Debye model is applied. The Debye temperature is determined from the non-equilibrium Gibbs function.     

Formation of Ge35In8S57 amorphous films for optical applications

Thin films of In-doped Ge-S in the form of Ge₃₅In₈S₅₇ with different film thickness were deposited using an evaporation method. The X-ray diffraction studies demonstrate that the as-prepared films are amorphous in nature for these films. Some optical constants were calculated at a thickness of 150, 300, 450 and 900?nm and annealing temperature of 373, 413, 437 and 513?K. Our optical observations show that the mechanism of the optical transition obeys the indirect transition. It was found that the energy gap, E_g, decreases from 2.44 to 2.20?eV with expanding the thickness of the film from 150 to 900?nm. On the other hand, it was found that E_g increases with annealing temperature from 373 to 513?K. The increment in the band gap can be attributed to the gradual annealing out of the unsaturated bonds delivering a decreasing the density of localized states in the band structure. Using the single oscillator model, the dispersion of the refractive index is described. The dispersion constants of these films were calculated with different both thickness and annealing temperatures. Additionally, both of nonlinear susceptibility, χ⁽³⁾ and nonlinear refractive index, n₂ were calculated.     

Pharmacotherapeutics Applications and Chemistry of Chalcone Derivatives

Chalcones have been well examined in the extant literature and demonstrated antibacterial, antifungal, anti-inflammatory, and anticancer properties. A detailed evaluation of the purported health benefits of chalcone and its derivatives, including molecular mechanisms of pharmacological activities, can be further explored. Therefore, this review aimed to describe the main characteristics of chalcone and its derivatives, including their method synthesis and pharmacotherapeutics applications with molecular mechanisms. The presence of the reactive α,β-unsaturated system in the chalcone’s rings showed different potential pharmacological properties, including inhibitory activity on enzymes, anticancer, anti-inflammatory, antibacterial, antifungal, antimalarial, antiprotozoal, and anti-filarial activity. Changing the structure by adding substituent groups to the aromatic ring can increase potency, reduce toxicity, and broaden pharmacological action. This report also summarized the potential health benefits of chalcone derivatives, particularly antimicrobial activity. We found that several chalcone compounds can inhibit diverse targets of antibiotic-resistance development pathways; therefore, they overcome resistance, and bacteria become susceptible to antibacterial compounds. A few chalcone compounds were more active than conventional antibiotics, like vancomycin and tetracycline. On another note, a series of pyran-fused chalcones and trichalcones can block the NF-B signaling complement system implicated in inflammation, and several compounds demonstrated more potent lipoxygenase inhibition than NSAIDs, such as indomethacin. This report integrated discussion from the domains of medicinal chemistry, organic synthesis, and diverse pharmacological applications, particularly for the development of new anti-infective agents that could be a useful reference for pharmaceutical scientists.