The hydromagnetic flow between eccentric cylinders with velocity slip at the cylinder walls

The hydrodynamic flow between two eccentric cylinders is examined for small values of modified Reynolds number, porosity parameter and the non-dimensional slip velocity parameter in the presence of a radial magnetic field.The stream function and the pressure distribution are calculated and the results are presented graphically.     

Structure-aided drug development of potential neuraminidase inhibitors against pandemic H1N1 exploring alternate binding mechanism

Molecular Diversity - The rate of mutability of pathogenic H1N1 influenza virus is a threat. The emergence of drug resistance to the current competitive inhibitors of neuraminidase, such as...     

Removal of a single minor-groove functional group eliminates A-tract curvature

Much of the work in studying the phenomenon of A-tract curvature has involved the insertion of modified residues into the A-tract sequence and then cross-correlation of the structural differences with the resulting curvature effects. In the A-tract sequence d(A-T)5, removal of a single functional group (the O2-carbonyl of the central dT residue) by its replacement with hydrogen completely eliminates the curvature properties. This atom-specific change was accomplished by using the C-nucleoside dm32P in which the O2-carbonyl is replaced with -H but normal Watson-Crick hydrogen bonding is maintained. Similar derivatives with -F (dF62P) or -CH3 (dm62P) when present for the central dT residue also eliminate curvature. Finally, we have shown that the extent of curvature for sequences containing this carbonyl are sensitive to the [Mg2+], while those lacking the carbonyl show little to no Mg2+ dependence, strongly suggesting, we believe, a role for Na+/Mg2+ cooperative interactions in the minor groove to explain the curvature phenomenon.     

Molecular precursors for the preparation of homogenous zirconia-silica materials by hydrolytic sol-gel process in organic media. Crystal structures of [Zr{OSi(O(t)Bu)3}4(H2O)2]·2H2O and [Ti(O(t)Bu){OSi(O(t)Bu)3}3

[Zr(OPr(i))(4)·Pr(i)OH] reacts with [HOSi(O(t)Bu)(3)] in anhydrous benzene in 1:1 and 1:2 molar ratios to afford alkoxy zirconosiloxane precursors of the types [Zr(OPr(i))(3){OSi(O(t)Bu)(3)}] (A) and [Zr(OPr(i))(2){OSi(O(t)Bu)(3)}(2)] (B), respectively. Further reactions of A or B with glycols in 1:1 molar ratio afforded six chemically modified precursors of the types [Zr(OPr(i))(OGO){OSi(O(t)Bu)(3)}] (1A-3A) and [Zr(OGO){OSi(O(t)Bu)(3)}(2)] (1B-3B), respectively [where G = (-CH(2)-)(2) (1A, 1B); (-CH(2)-)(3) (2A, 2B) and (-CH(2)CH(2)CH(CH(3)-)} (3A, 3B)]. The precursors A and B are viscous liquids, which solidify on ageing whereas the other products are all solids, soluble in common organic solvents. These were characterized by elemental analyses, molecular weight measurements, FAB mass, FTIR, (1)H, (13)C and (29)Si-NMR studies. Cryoscopic molecular weight measurements of all the products, as well as the FAB mass studies of 3A and 3B, indicate their monomeric nature. However, FAB mass spectrum of the solidified B suggests that it exists in dimeric form. Single crystal structure analysis of [Zr{OSi(O(t)Bu)(3)}(4)(H(2)O)(2)]·2H(2)O (3b) (R(fac) = 11.9%) as well as that of corresponding better quality crystals of [Ti(O(t)Bu){OSi(O(t)Bu)(3)}(3)] (4) (R(fac) = 5.97%) indicate the presence of a M-O-Si bond. TG analyses of 3A, B, and 3B indicate the formation of zirconia-silica materials of the type ZrO(2)·SiO(2) from 3A and ZrO(2)·2SiO(2) from B or 3B at low decomposition temperatures (≤200 °C). The desired homogenous nano-sized zirconia-silica materials [ZrO(2)·nSiO(2)] have been obtained easily from the precursors A and B as well as from the glycol modified precursors 3A and 3B by hydrolytic sol-gel process in organic media without using any acid or base catalyst, and these were characterized by powder XRD patterns, SEM images, EDX analyses and IR spectroscopy.     

Highly sensitive LC-MS/MS-ESI method for simultaneous quantitation of albendazole and ricobendazole in rat plasma and its application to a rat pharmacokinetic study

A highly sensitive and specific LC-MS/MS-ESI method was developed for simultaneous quantification of albenadazole (ABZ) and ricobendazole (RBZ) in rat plasma (50 μL) using phenacetin as an internal standard (IS). Simple protein precipitation was used to extract ABZ and RBZ from rat plasma. The chromatographic resolution of ABZ, RBZ and IS was achieved with a mobile phase consisting of 5 m m ammonium acetate (pH 6) and acetonitrile (20:80, v/v) at a flow rate of 1 mL/min on a Chromolith RP-18e column. The total chromatographic run time was 3.5 min and the elution of ABZ, RBZ and IS occurred at 1.66, 1.50 and 1.59 min, respectively. A linear response function was established for the ranges of concentrations 2.01-2007 and 6.02-6020 ng/mL for ABZ and RBZ, respectively. The intra- and inter-day precision values for ABZ and RBZ met the acceptance as per FDA guidelines. ABZ and RBZ were stable in battery of stability studies, viz. bench-top, auto-sampler and freeze-thaw cycles. The developed assay was applied to a pharmacokinetic study in rats.     

Thermoanalytical studies of oxovanadium(IV)hydroxamate complexes

The thermal decomposition behavior of oxovanadium(IV)hydroxamate complexes of composition [VO(acac)(C₆H₅C(O)NHO)] (I), [VO(C₆H₅C(O)NHO)₂] (II), [VO(acac)(4-ClC₆H₄C(O)NHO)] (III), [VO(4-ClC₆H₄C(O)NHO)₂] (IV) (where acac = (CH₃COCHCOCH₃ ^–) synthesized from the reactions of VO(acac)₂ with equi- and bimolar amounts of potassium benzohydroxamate and potassium 4-chlorobenzohydroxamate in THF + MeOH solvent medium has been studied by TG and DTA techniques. TG curves indicated that complexes I, II, and IV undergo decomposition in single step to yield VO₂ as the final residue, while complex III decomposes in two steps to yield VO(acac) as the likely intermediate and VO₂ as the ultimate product of decomposition. The formation of VO₂ has been authenticated by IR and XRD studies. From the initial decomposition temperatures, the order of thermal stability for the complexes has been inferred as IV > I > III > II.     

A Novel Approach in Treatment of Tuberculosis by Targeting Drugs to Infected Macrophages Using Biodegradable Nanoparticles

Mycobacterium tuberculosis, the causative agent of tuberculosis is now causing death of more than 10 million people. Because of the development of drug-resistant TB, drug delivery to the infected site through nanoparticle had been studied for long time. Nanoparticles indicate different sorts of association with the natural particles of the body. Nanoparticles can be used as controlled or specific drug delivery system. It can be through temporal controlled or can be distribution controlled. Glucose polymer-based nanoparticles might play an important role as drug delivery system in case of targeted drug delivery in the infected site of the body or in infected macrophages, as they are biodegradable so there should not be any side effects of these particles in the body and also they show very slow immune response. CD4, Beta 1, TGFb-1, IL-2, IL-13 SEC14L1, GUSB, BPI, and CCR7 are major biomarkers secreted after infection of this bacterium by the macrophages which can be used for targeted drug delivery in infected macrophages. As these markers can be used for delivery of drugs at destined position, they can be very beneficial in reducing toxicities of antituberculer drugs to the other uninfected sites and in operating only the infected macrophages.     

Preparation of dibromoacetic anhydride and its reactions with Bi2O3 and CrO3 to form metal dibromoacetates

Dibromoacetic anhydride was prepared by reacting dibromoacetic acid with phosphorus(V) oxide in carbon tetrachloride at 85°C for 11 h. It reacts with Bi₂O₃ and CrO₃ in CCl₄ on prolonged refluxing forming Bi(CHBr₂COO)₃ and Cr (CHBr₂COO)₃, respectively. These new compounds were characterized by elemental analyses, IR, ¹H NMR and mass spectroscopy.     

New sol–gel precursors for binary oxides of antimony,Sb<Subscript>2</Subscript>O<Subscript>3</Subscript> (senarmonite) and α-Sb<Subscript>2</Subscript>O<Subscript>4</Subscript>: synthesis and characterization of some ketoximate modified antimony(III) alkoxides

Hydrolysis of pure Sb(OPrⁱ)₃ by sol–gel method followed by sintering at 500 °C yields microcrystallites of Sb₂O₃ (senarmonite phase). Under similar conditions bimetallic alkoxide, [NaSb(OPrⁱ)₄], yields a mixture of binary oxides Sb₂O₃ and Sb₂O₄. Chemical modification of Sb(OPrⁱ)₃ with oximes forms monomeric products of the type [Sb(OPrⁱ)_3−n {ON=C(CH₃)R} _n ] {where R = CH₃, n = 1 [1]; n = 2 [2]; n = 3 [3]; R = 2-C₅H₄N, n = 1 [4]; n = 2 [5]; n = 3 [6]; R = 2-C₄H₃O, n = 1 [7]; n = 2 [8]; n = 3 [9]; R = 2-C₄H₃S, n = 1 [10]; n = 2 [11]; n = 3 [12]}. The liquid products [1–3, 7 & 10] were purified by distillation while the solids by recrystallization. All these products were characterized by elemental analyses, IR, NMR (¹H and ¹³C{¹H}) and representative derivatives [1], [2] and [3] by FAB mass studies. On the basis of these studies, a distorted pyramidal structure for all the derivatives may be assumed in the solution state containing an end-on coordination of oximes with the metal atom. Hydrolysis of the distilled precursors [1], [2] and [3] under sol–gel conditions yields pure nano-sized α-Sb₂O₄. All the oxides were characterized by XRD, SEM and EDX analysis exhibiting minimum particle size for the oxide obtained from the precursor [3].