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排序方式: 共有796条查询结果,搜索用时 15 毫秒
51.
Matthew B. Kerby Jane C. Urban Lea Mouallem Anubhav Tripathi 《Applied biochemistry and biotechnology》2009,159(1):208-220
Proposed methods for detecting circulatory system disease include targeting ultrasound contrast agents to inflammatory markers
on vascular endothelial cells. For antibody-based therapies, soluble forms of the targeted adhesion proteins of the immunoglobulin
superfamily (IgSF) reduce adhesion yet were left unaccounted in prior reports. Microspheres labeled simply with a maximum
level of antibodies can reduce the diagnostic sensitivity by adhering to proteins expressed normally at a low level, while
sparsely coated particles may be rendered ineffective by circulating soluble forms of the targeted proteins. A new microdevice
technique is applied to simultaneously measure the adhesion profile to a series of IgSF-protein-coated surfaces. In this investigation,
we quantify the in vitro binding characteristics of 5-μm microspheres to oriented intercellular adhesion molecule-1 (ICAM-1)
and vascular cell adhesion molecule-1 (VCAM-1) protein-coated surfaces in the presence of human serum at physiological concentrations.
Defined regions of a slide were coated with recombinant chimeric Fc-human ICAM-1 and VCAM-1 in variable ratios but constant
total concentration. Monoclonal human anti-ICAM-1 or anti-VCAM-1 antibodies in competition with non-binding mouse anti-rabbit
antibodies coat the microsphere surface at a constant surface density with variable yet controlled surface activities. Using
multiple slide surface IgSF protein and microsphere antibody concentrations, an adhesion profile was developed for the microspheres
with and without IgSF proteins from human serum, which demonstrated that exposure to serum reduced microsphere binding, on
average, more than 50% compared to the no-serum condition.. The serum effects were limited to antibodies on the microsphere,
since binding inhibition was reversed after rinsing serum from the system and fresh antibody-coated microspheres were introduced.
This analysis quantifies the binding effects of soluble IgSF proteins from human serum on antibody-based targeted ultrasound
detection and drug delivery methods. 相似文献
52.
MK Talari AB Abdul Majeed DK Tripathi M Tripathy 《Chemical & pharmaceutical bulletin》2012,60(7):818-824
The application of nanomaterials has gained considerable momentum in various fields in recent years due to their high reactivity, excellent surface properties and quantum effects in the nanometer range. The properties of zinc oxide (ZnO) vary with its crystallite size or particle size and often nanocrystalline ZnO is seen to exhibit superior physical and chemical properties due to their higher surface area and modified electronic structure. ZnO nanoparticles are reported to exhibit strong bacterial inhibiting activity and silver (Ag) has been extensively used for its antimicrobial properties since ages. In this study, Ag doped ZnO nanoparticles were synthesized by mechanochemical processing in a high energy ball mill and investigated for antimicrobial activity. The nanocrystalline nature of zinc oxide was established by X-ray diffraction (XRD) studies. It is seen from the XRD data obtained from the samples, that crystallite size of the zinc oxide nanoparticles is seen to decrease with increasing Ag addition. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) data also supported the nanoparticle formation during the synthesis. The doped nanoparticles were subjected to antimicrobial investigation and found that both increase in Ag content and decrease in particle size contributed significantly towards antimicrobial efficiency. It was also observed that Ag doped ZnO nanoparticles possess enhanced antimicrobial potential than that of virgin ZnO against the studied microorganisms of Escherichia coli and Staphylococcus aureus. 相似文献
53.
Vinod K. Tiwari Archana Singh Hakkim A. Hussain Bhuwan B. Mishra Vyasji Tripathi 《Monatshefte für Chemie / Chemical Monthly》2007,138(7):653-658
Summary. A convenient and high yielding method for the synthesis of diverse dithiocarbamates having various substituents including
alkyl, aryl, heteroaryl, and alkylaryl at the thiol chain or at the amine chain or at both thiol and amine chains were developed
by the one-pot reaction of mercaptans, amines, and bis(benzotriazolyl)methanethione in presence of amidine base under mild
reaction conditions. 相似文献
54.
Titanosilicates with complete or partial substitution of Ge or Nb in the framework and having the mineral pharmacosiderite topology were hydrothermally prepared and their ion-exchange properties towards Cs were studied for Ti/Ge/Si, Ti/Si, Nb/Ti/Si and pure Ge phases. The basis for the differences in the ion exchange properties measured as distribution coefficients (Kd) for these materials are detailed via structural characterization using the Rietveld refinement technique on the X-ray powder diffraction data. The differences in affinity towards Cs+ result either from the degree of hydration of the exchanger resulting in different coordination environments or the position of cesium ion in the eight-ring channel. 相似文献
55.
Reetesh Kumar Pinki Tripathi Fabio Rogerio de Moraes Ícaro P. Caruso Medicherla V. Jagannadham 《Applied biochemistry and biotechnology》2014,172(2):658-671
Streblin, a serine proteinase from plant Streblus asper, has been used to investigate the conformational changes induced by pH, temperature, and chaotropes. The near/far UV circular dichroism activities under fluorescence emission spectroscopy and 8-aniline-1-naphthalene sulfonate (ANS) binding have been carried out to understand the unfolding of the protein in the presence of denaturants. Spectroscopic studies reveal that streblin belongs to the α+β class of proteins and exhibits stability towards chemical denaturants, guanidine hydrochloride (GuHCl). The pH-induced transition of this protein is noncooperative for transition phases between pH 0.5 and 2.5 (midpoint, 1.5) and pH 2.5 and 10.0 (midpoint, 6.5). At pH 1.0 or lower, the protein unfolds to form acid-unfolded state, and for pH 7.5 and above, protein turns into an alkaline denatured state characterized by the absence of ANS binding. At pH 2.0 (1 M GuHCl), streblin exists in a partially unfolded state with characteristics of a molten globule state. The protein is found to exhibit strong and predominant ANS binding. In total, six different intermediate states has been identified to show protein folding pathways. 相似文献
56.
Eti Mehrotra Jyotsna Vishwakarma Avinash C. Tripathi Pankaj K. Sonar 《Natural product research》2019,33(4):568-572
The present study explored the schizonticidal potential of traditionally used Magnolia champaca (L.) Baill. ex. Pierre flowers, identifying constituents of interest. The extraction of phytoconstituents was carried out by microwave-assisted technique, isolated via column chromatography, and characterised by various physicochemical, spectral (IR, 1H-NMR and Mass) and chromatographic (HPTLC) techniques. Both the isolated compounds (parthenolide and costunolide diepoxide) exhibited potent schizonticidal antimalarial activity during primary screening in rodent models, with maximum parasitaemia suppression (85.18% and 83.65%, respectively) at a dose of 20 mg/kg body weight when compared to the standard drugs chloroquine and artesunate. In silico techniques were employed to identify the probable biological target and mechanism of action of these isolated compounds. Molecular docking studies also predicted the binding orientations and multi-targeted action of these compounds, in particular costunolide diepoxide with maximum affinity towards SERCA and DHFR proteins. Additionally, favourable in silico ADMET parameters were envisaged through various computational programmes. 相似文献
57.
Benzotrithiophene (BTT) isomers were investigated using density functional theory (DFT) and time‐dependent DFT (TD‐DFT) with the aim to explore their structures, linear optical properties, vertical and adiabatic ionization potentials (IPv and IPa), electron affinities (EAv and EAa), and reorganization energies (λ). The computed bond lengths and bond angles at the B3LYP/6–311+G (d, p) level of theory are in good agreement with experimental crystal structures of the known BTTs. These molecules are planar with zero dihedral angle, making them an ideal backbone for high charge mobility. The UV–visible spectra of BTT isomers are in the range 280–360 nm. All BTT isomers have low hole/electron reorganization energies, which is the main characteristic of good hole/electron transporting materials, and these isomers in turn have potential applications in the field of organic materials. 相似文献
58.
β-Keto esters and acetyl acetone on condensation with glycosylated amino esters in the presence of IR-120 resin resulted in high yields of glycosyl enamino esters or ketones. The latter on cyclisation with NaH in toluene at reflux gave 6-glycosyl-5,6-dihydro-1H-pyridin-4-ones in fair to good yields. 相似文献
59.
The 25% niobium substituted crystalline titanosilicate with the composition Na1.5Nb0.5Ti1.5O3SiO4·2H2O (Nb-TS) was synthesized under hydrothermal conditions. Its selectivity for radioactive 137Cs and 89Sr was compared with the TS, Na2Ti2O3SiO4·2H2O, having sitinakite topology. The Nb-TS shows significantly higher uptake value for 137Cs but lower for 89Sr than the TS. To investigate the origin of selectivity, the ion exchanged Cs+ and Sr2+ forms with the composition, CsxNaHyNb0.5Ti1.5O3SiO4·zH2O (x=0.1, 0.2 and 0.3, x+y=0.5 and z=1-2) and Sr0.2Na0.6H0.5Nb0.5Ti1.5O3SiO4·H2O, respectively, were structurally characterized from the X-ray powder diffraction data using the Rietveld refinement technique. Simultaneously the kinetics of 137Cs and 89Sr uptake was investigated for the NbV free and doped samples. While the Cs+ and Sr2+ exchanged form of Nb-TS and the Cs+ exchanged form of TS retain the symmetry of the parent compound, the Sr2+ exchanged form of TS undergoes a symmetry change. The differences in the uptake of Cs+ and Sr2+ result from the different coordination environments of cesium and strontium in the eight-ring channel, that result from various hydration sites in the tunnel. The origin of selectivity appears to arise from the higher coordination number of cesium or strontium. Other effects due to NbV substitution are reflected in the increase of both, the a- and c-dimensions and thus the unit cell volume, and the population of water vs. Na+ in the channel to charge-balance the Nb5+↔Ti4+ substitution. 相似文献
60.
Shashank Tripathi Achu Chandran Tilak Joshi Anil Kumar Ajay Dhar 《Liquid crystals》2013,40(9):1255-1262
In this article, a newly synthesised ferroelectric liquid crystal (FLC) material, namely LAHS 22, has been characterised. The characterisation of the FLC material has been performed using dielectric relaxation spectroscopy, differential scanning calorimetry and polarisation optical microscopy. We observed an enhancement in the dielectric and electro-optical properties of the FLC material by incorporating gold nanoparticles (GNPs)-decorated multiwalled carbon nanotubes (MWCNTs). The GNPs-decorated MWCNTs cause an increment in dielectric dispersion (up to kHz), absorption, spontaneous polarisation and rotational viscosity of the FLC material. The pure and GNPs-decorated MWCNTs doped FLC cells were analysed by means of various dielectric spectroscopic and optical measurements. The observed enhancement in the dielectric and electro-optical properties of the FLC material has also been studied with concentration of GNPs-decorated MWCNTs in FLC material. The GNPs-decorated MWCNTs/FLC composites are not only of fundamental importance, but also useful materials for device applications such as liquid crystal displays and memory devices. 相似文献