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71.
Nandiraju V. S. Rao Manoj K. Paul Thatavarthi R. Rao Archana Prasad 《Liquid crystals》2013,40(9):1243-1246
The reaction of N-(4-n-alkoxysalicylidene)-4′-n-alkylanilines with freshly prepared lanthanide salts leads to mesomorphic terbium and dysprosium complexes exhibiting the smectic A phase. 相似文献
72.
Polymerization of acrylamide monomer, initiated by the redox system involving acidified ceric ammonium sulfate and 2-mercaptoethanol (2-ME) was carried out in an aqueous medium at 25° C. White, rigid polyacrylamide, isolated under controlled experimental conditions, showed a molecular weight of 1.5 × 104 from viscosity measurements. The rate of monomer (M) conversion to polymer was found to be proportional to [M]1.5, [2-ME]0.5, and [Ce(IV)]0.4. Further, the rate of disappearance of ceric ion was observed to be directly proportional to [2-ME] and independent of [M] in the range of 0.16–0.48 mole/liter. The explanation of the above proportionalities is given in terms of a proposed reaction mechanism. Values of the usual rate constants, kr, k0/kt and kt./kp ½ have been computed. 相似文献
73.
Blend membranes comprising cellulose acetate and polysulfone (CA/PSf) were prepared through a solution casting method using a different concentration of polyvinylpyrrolidone (PVP) as the pore former. Fourier transform infrared spectroscopy (ATR-FTIR) was used to investigate structural properties of membranes. Membranes morphology and its thermal properties were characterized by scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The strength of membranes was studied by mechanical stability. The effect of PVP concentration on separation performance of the prepared membranes was studied. The separation performance of prepared membranes was tested by using an aqueous solution of cadmium metal complexed with humic acid. The results showed that an increase in the PVP concentration in the cast film from 0 to 3 wt% increased the thermal stability, water content (%), pure water flux, and solute rejection. SEM results showed that the pore size decreased but the number of pores increased on an increase in the PVP concentration. 相似文献
74.
Angesh Chandra Archana Chandra K. Thakur 《Russian Journal of General Chemistry》2013,83(12):2375-2379
Ion-conducting nanocomposite polymer electrolyte films based on poly(ethylene oxide)-NaPO3 3: 1 with up to 15 wt % of SiO2 have been prepared using recently developed hot-press technique instead of conventional solution cast method. With 7 wt % of SiO2, the film conductivity has been enhanced by an order of magnitude. The materials have been characterized by Fourier transform infrared spectrometry and thermogravimetric analysis. For the composition with the highest conductivity, the temperature dependences of ionic mobility, mobile ions concentration, ionic transference number, and ionic drift velocity have been determined. Dielectric constant and dielectric loss have been measured. The conductivity enhancement has been discussed on the basis of existing theories of dielectrics. 相似文献
75.
Harsimran Kaur Archana Chaudhary Inderpreet Kaur Kashmir Singh Lalit M. Bharadwaj 《Journal of nanoparticle research》2011,13(6):2295-2303
Nanotechnology is playing an important role in drug delivery to overcome limitations of conventional drug delivery systems
in terms of solubility, in vivo stability, pharmacokinetics, and bio-distribution. The controlled transportation of drug into
the cell and within the cell is a major challenge to be addressed. Cellular molecular motors have been exploited for their
cargo carrying capacity for various applications including engineering and health care. Combination of nanotechnology and
biomolecular motors can address some of the challenges in drug delivery. In the present study, transportation of drug nanocomposites
has been demonstrated. Nanocomposites of 6-mercaptopurine and levodopa drugs (cancer and Parkinson’s disease, respectively)
were prepared with gold nanoparticles (GNPs) by covalent attachment and these nanocomposites were attached to actin filaments.
These nanocomposites were in-turn transported by actin filaments on myosin tracks. Characterization of drug nanocomposites
formation was done by UV–Vis spectroscopy, field emission scanning electron microscopy, transmission electron microscopy,
and confocal microscopy. GNP composites of 6-mercaptopurine and levodopa were formed by sulfide and amide bond formation,
respectively. Average velocity of actin filament attached to nanocomposites was found to be 3.17 and 3.89 μm/s for levodopa
and 6-mercaptopurine, respectively, as compared to actin filaments with velocity of 4.0–6.0 μm/s. Three concepts have been
proposed for the study of drug transportation into the cell based on polycationic complex formation, interaction of actin
with cellular myosin and Biomolecular Adaptor for Retrograde Transport (BART) technology. The aspects of this study heads
toward the development of an approach to utilize molecular motors for nanoscale transportation endogenously. 相似文献
76.
A novel and highly selective method has been developed for the determination of aromatic primary amines by their conversion to dithiocarbamates by reaction with carbon disulphide, and then to isothiocyanates, which are volatile, by heating in the presence of a heavy metal ion. Zinc(II) was selected owing to its low toxicity and optimum yield of isothiocyanates. The latter were sampled by headspace-solid phase microextraction (HS-SPME) on divinylbenzene-carboxen-polydimethylsiloxane fibre, 50/30 μm. The HS-SPME procedure was optimized to provide adequate limits of detection in the analysis of aromatic amines in their real samples by gas chromatography with mass spectrometry (GC–MS) or flame ionization detection (GC–FID). The method gave rectilinear calibration graph, correlation coefficient and limit of detection, respectively, over the range 0.08–100 μg L−1, 0.9950–0.9990 and 25–240 ng L−1 in gas chromatography–mass spectrometry, and 0.01–10 mg L−1, 0.9910–0.9991 and 0.8–3.0 μg L−1 in gas chromatography–flame ionization detection. At two different levels, 10 and 40 μg L−1, the range of intra-day RSD was 3.7–8.5% (GC–MS) and 3.3–9.2% (GC–FID), respectively. The proposed method is simple and rapid, and has been applied to determine aromatic primary amines in the environmental waters, food samples of ice cream powder and soft drinks concentrate, and food colours. The intra-day RSD in the analysis of real samples by GC–MS was in the range 3.6–6.2%. The food/colour samples were found to contain elevated levels of aniline and 2-toluidine. 相似文献
77.
The synthesis and mesomorphic properties of a homologous series of N-(2-hydroxy-4-n-alkoxybenzylidene)-4'-n-decylphenylanilines and their platinum(II) and oxovanadium(IV) complexes are reported. All the ligands and their metal chelates exhibit enantiotropic mesophases, predominantly smectic A and smectic C phases. The transition temperatures and enthalpies have been determined for most of the compounds. The platinum(II) complexes have higher melting points and mesophase thermal stabilities. However, the oxovanadium(IV) complexes have a wider thermal range for the mesophase. Both platinum(II) and oxovanadium(IV) complexes containing only a chain on the biphenyl moiety exhibit a nematic phase. 相似文献
78.
79.
A. K. Gupta S. K. Sharma Archana Venaik 《Applied Physics A: Materials Science & Processing》1987,42(2):167-171
Important electrothermographic characteristics such as charge acceptance, surface-potential decay with and without exposure to infrared radiations, retention of surface charge, contrast potential and residual potential of pure and sensitized cellulose acetate layers have been investigated. An attempt has been made to explain the results on the basis of electrical properties. Leucomalachite Green (LMG) is found to be very effective in controlling the thermosensitivity in the cellulose acetate layers. Cellulose acetate layer sensitized with 20% by wt of LMG shows a suitable high-contrast potential of 890 V with zero residual potential on heating its surface to 62° C and is a suitable material for electrothermographic and related applications. 相似文献
80.
Cationic and non‐ionic surfactant mediated systems have been studied as mobile phases in thin chromatographic studies of opium alkaloids on silica gel G. The effect of surfactant concentration below and above its critical micellar concentration on the mobility of alkaloids was examined. The influence of different alcohols (methanol, ethanol, propanol and butanol) in micellar solutions on the mobility and separation efficiency of alkaloids was assessed. The technique has also been applied for semiquantitative determination of codeine sulphate (2.5–35 μg) and papaverine. HCl (2.5–30 μg) in mixtures as well as in pharmaceuticals. The lower limits of detection of papaverine. HCl and codeine sulphate were 1.0 μg and 1.5 μg, respectively. 相似文献