C—H...O hydrogen‐bonding and C—H...π interactions in 3‐(4‐fluorophenyl)‐1,5,7‐trimethyl‐1,2,3,4‐tetrahydropyrido[2,3‐d]pyrimidine‐2,4‐dione

In the title compound, C₁₆H₁₄FN₃O₂, a diverse set of weak intermolecular C—H...π, π–π and C—H...O interactions link the molecules into sheets. The C—H...O interactions generate centrosymmetric rings with a graph‐set motif of R₂²(14) and chains with a C(8) motif.     

Ethyl 3‐amino‐6‐phenyl‐4‐tolylthieno[2,3‐b]pyridine‐2‐carboxylate

In the title compound, C₂₃H₂₀N₂O₂S, the central thieno­pyridine ring system is essentially planar, the dihedral angle between the planes of the two rings being 0.3 (2)°. The terminal ethyl carboxyl­ate group is twisted by 26.7 (3)° away from the central ring system. A short intramolecular hydrogen bond involving the amino N atom and the carbonyl O atom [N⋯O = 2.806 (4) Å] forms a pseudo‐six‐membered ring. Significant intermolecular C—H⋯N, C—H⋯O and C—H⋯π interactions contribute strongly to the stability of the structure, along with weak π–π‐stacking interactions.     

Optimal replenishment time for retailer under partial upstream prepayment and partial downstream overdue payment for quadratic demand

In competitive edge, the proffer of delay payment is of great consequence tool to boost the market demand by exerting influence of more customers. In opposition to, merchandiser may be asked to pay some per cent of purchasing cost before receiving products to reduce the risk of cancellation of order. In this article, optimal replenishment time for merchandiser under partial upstream prepayment and partial downstream overdue payment is presented under quadratic demand with three different models: (1) without deterioration, (2) with constant deterioration and (3) maximum fixed-lifetime deterioration as loss of utility is the real situation of products like fruits, vegetables, juices, etc., and to reduce deterioration of the product, merchandiser spends capital on preservation technology to preserve the item. Quadratic demand is suitable for the products for which demand increases initially and afterward it starts to decrease. The decision policies are analysed for the merchandiser. The objective is to minimize merchandiser’s total cost with respect to decision variables. The models are supported with numerical examples. Sensitivity analysis is carried out to derive insights for decision maker.     

A simple HPLC method for quantitation of quercetin in herbal extracts

A reversed-phase HPLC method with UV detection was developed for the determination of quercetin. The method produced linear response over a wide concentration range, with an average accuracy of 95% and average intra- and interday variation of 0.75 and 0.3, respectively. The exactness of the method was proven by determining the recovery rates from 50 to 150% of standard concentration, which were found within the acceptable range of 95 to 105%. The method was used for quantitation of quercetin in the extracts of Psidium guajava, Vitis vinifera, and extracts rich in quercetin and other flavonols in the flavonoid family.     

Characterization of keratin–collagen 3D scaffold for biomedical applications

Fabrication of keratin–collagen (KC) 3D scaffold with improved thermal denaturation rate is reported. In vitro application of (KC) scaffold stimulates basic extra cellular matrix constituents. KC Scaffold considerably reduced undesirable properties of both collagen and keratin while collagen incorporation reduces the fragility with increases of strength and flexibility in the scaffold. In addition to this, the scaffold showed homogenous well‐interconnected pores in the range of 10–100 µm when observed in scanning electron microscope. Usage of keratin in KC scaffold offers increased biodegradation rate and higher denaturation rate in addition to its rapid cell growth with normal morphology ultimately reaching cell population of 3.9–9.7 million per cm³ after 48 hr in KC scaffold. Circular dichroism (CD) and Fourier transform spectroscopy (FT‐IR) of KC showed presence of helical structure of collagen and ß‐turns of keratin confirming retention of native structures of both the proteins KC scaffold showed good swelling behavior and water uptake. Our study strongly supports the superidity of KC scaffold over the collagen or keratin when they are independently used for tissue engineering applications. Copyright © 2011 John Wiley & Sons, Ltd.     

DFT studies,Hirshfeld surface analysis and crystal structure of novel silver complex of sulfapyridine with secondary ligand pyridine

Silver complex of sulfapyridine has been synthesized and characterized by IR, NMR and PL. The crystal structure has been determined by X-ray diffraction technique. Silver complex of sulfapyridine with secondary ligand pyridine crystallizes in monoclinic space group P2₁/n with lattice parameter: a = 17.8075(4)Å, b = 10.7885(3)Å, c = 17.8075(4)Å, β = 94.12(1)Å and Z = 4. To study the nature of intermolecular interactions and their quantitative contributions towards the crystal packing, Hirshfeld surfaces and accordingly the fingerprint plot analysis have been performed. Molecular properties such as NBO analysis, Homo-Lumo energy calculation have been carried out by DFT method. Furthermore, the antimicrobial activity of silver complex of sulfapyridine and free ligand is studied by the dilution method.     

Synthesis,structure, DNA binding studies and nuclease activities of two luminescent neodymium complexes

Two neodymium(III) complexes, [Nd(Phen)(NO₃)₃(DMF)₂] (1) and [Nd(Phen)₂(NO₃)₃] (2) (phen = 1,10-phenanthroline; DMF = dimethylformamide), have been synthesized with a view to design artificial luminescent nucleases and nuclease mimics. The complexes were characterized by spectroscopic, powder, and single crystal XRD studies. The complexes, as expected, have luminescent properties. The DNA binding studies of both complexes have been carried out by spectroscopic studies e.g. electronic absorption (UV–Vis), fluorescence emission as well as viscosity measurements. The nuclease activity of the complexes has been established by gel electrophoresis using pUC19 circular plasmid DNA. The results of DNA binding as well as DNA cleavage activity and the model studies of interaction with pNPP indicate that both neodymium complexes demonstrate nuclease activity through phosphoester bond cleavage.     

New method for chloroamidation of olefins. Application in the synthesis of N-glycopeptides and anticancer agents

Chloroamidation of olefins using a new reagent system (COCl)2-AgNO3-CH3CN was observed. Various glycals with this reagent system produce 2-chloro-1-acetamido sugars in good yields which, in turn, were converted to free amino derivatives and various glycopeptides. The acetamido sugar derivatives and free amines were found to be promising anticancer agents against the U-87 malignant glyoma (a brain tumor) cell line with IC-50=1 nm-22 microM, and they were found to be far less cytotoxic against a normal human embryonic kidney cell line.     

Evaluation of Ethylene Propylene Diene Terpolymer based insulation against Nitrile rubber based insulation for large Composite Rocket Motor Casing

Even though literature available on EPDM is abundant, the data on physical, mechanical, thermal, interface properties and ablative performance as specifically required for the design and acceptance of internal insulation of large Composite Rocket Motor Casing is scant in the plethora of literature available in the subject of EPDM insulation. This gave the impetus to take up this experimental work wherein most promising formulation of EPDM with Kevlar and silica as reinforcing fillers and with only silica as reinforcing filler were thoroughly characterized for the insulation requirements of large Composite Rocket Motor Casing and compared with the performance of proven Nitrile rubber based insulation. The significant findings which are unique, are discussed in this paper.