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81.
Shashank Shukla Joseph Favata Vikas Srivastava Sina Shahbazmohamadi Anubhav Tripathi Anita Shukla 《Journal of polymer science. Part A, Polymer chemistry》2020,58(10):1365-1379
Developing optimized hydrogel products requires an in-depth understanding of the mechanisms that drive hydrogel tunability. Here, we performed a full 4 × 4 factorial design study investigating the impact of gellan, a naturally derived polysaccharide (1%, 2%, 3%, or 4% w/v) and CaCl2 concentration (1, 3, 7, or 10 mM) on the viscoelastic, swelling, and drug release behavior of gellan hydrogels containing a model drug, vancomycin. These concentrations were chosen to specifically provide insight into gellan hydrogel behavior for formulations utilizing polymer and salt concentrations expanding beyond those commonly reported by previous studies exploring gellan. With increasing gellan and CaCl2 concentration, the hydrogel storage moduli (0.1–100 kPa) followed a power-law relationship and on average these hydrogels had higher liquid absorption capability and greater total drug release over 6 days. We suggest that the effects of gellan and CaCl2 concentration and their interactions on hydrogel properties can be explained by various phenomena that lead to increased swelling and increased resistance to network expansion. 相似文献
82.
Sharma Deepika Radha Anu Kumar Pretam Kumar Sandeep Jassal Amanpreet K. Lata Suman Vikas Pandey Sushil K. 《Transition Metal Chemistry》2020,45(8):531-544
Transition Metal Chemistry - Nickel(II) complexes with octahedral coordination stabilized by N-donor ligands corresponds to [{(ArO)2PS2}2Ni·L2] [Ar = 4-(C2H5)C6H4 (3), and... 相似文献
83.
Design and Synthesis of High‐Affinity Dimeric Inhibitors Targeting the Interactions between Gephyrin and Inhibitory Neurotransmitter Receptors 下载免费PDF全文
Dr. Hans Michael Maric Vikram Babu Kasaragod Dr. Linda Haugaard‐Kedström Dr. Torben Johann Hausrat Prof. Dr. Matthias Kneussel Prof. Dr. Hermann Schindelin Prof. Dr. Kristian Strømgaard 《Angewandte Chemie (International ed. in English)》2015,54(2):490-494
Gephyrin is the central scaffolding protein for inhibitory neurotransmitter receptors in the brain. Here we describe the development of dimeric peptides that inhibit the interaction between gephyrin and these receptors, a process which is fundamental to numerous synaptic functions and diseases of the brain. We first identified receptor‐derived minimal gephyrin‐binding peptides that displayed exclusive binding towards native gephyrin from brain lysates. We then designed and synthesized a series of dimeric ligands, which led to a remarkable 1220‐fold enhancement of the gephyrin affinity (KD=6.8 nM ). In X‐ray crystal structures we visualized the simultaneous dimer‐to‐dimer binding in atomic detail, revealing compound‐specific binding modes. Thus, we defined the molecular basis of the affinity‐enhancing effect of multivalent gephyrin inhibitors and provide conceptually novel compounds with therapeutic potential, which will allow further elucidation of the gephyrin–receptor interplay. 相似文献
84.
85.
Mhaske Harshad P. Vaidya Vikas V. Menon Sasikumar N. Shailajan Sunita Gomes Noel A. 《平面色谱法杂志一现代薄层色谱法》2008,21(3):217-219
JPC – Journal of Planar Chromatography – Modern TLC - 相似文献
86.
Noel A. Gomes Ashutosh M. Pudage Santosh S. Joshi Vikas V. Vaidya Sagar A. Parekh 《Chromatographia》2008,68(7-8):541-550
A rapid and sensitive LC–MS–MS method has been developed and validated for simultaneous analysis of abacavir (ABA) and lamivudine (LAM) in human plasma. The analytes were extracted from human plasma by SPE. Nelfinavir (NEL) and emtricitabine (EMT) were used as the internal standards for ABA and LAM, respectively. An RP18 column enabled chromatographic separation of the analytes. The method involves simple isocratic chromatography and MS detection in positive-ionization mode. Validation of the method showed response was a linear function of concentration in the ranges 100.0–7000.0 ng mL?1 for ABA and 80.0–5000.0 ng mL?1 for LAM. At the LOQ levels, inter-run and intra-run precision were within 5.80 and 3.51%, respectively, for ABA and within 4.68 and 3.16%, respectively, for LAM. Overall recovery for ABA and LAM was 59.32 and 105.18%, respectively. Total elution time was 2 min only, which enabled quantification of more than 200 plasma samples per day. This validated method was used successfully for analysis of plasma samples from a bioequivalence study. 相似文献
87.
Singh V Koch DL Stroock AD 《Langmuir : the ACS journal of surfaces and colloids》2011,27(19):11813-11823
The collision of particles influences the behavior of suspensions through the formation of aggregates for adhesive particles or through the contributions of solid-body contacts to the stress for nonadhesive particles. The simplest estimate of the collision rate, termed the ideal collision rate, is obtained when particles translate and rotate with the flow but have no hydrodynamic or colloidal interactions. Smoluchowski calculated the ideal collision frequency of spherical particles in 1917. So far, little work has been done to understand rate of collision for nonspherical particles. In this work, we calculate the ideal collision rate for cylindrical particles over a broad range of particle aspect ratios r defined as the ratio of length to diameter. Monte Carlo simulations are performed with initial relative positions and orientations that model the rate of approach of noninteracting particles following Jeffery orbits with several choices of the orbit distribution. The role of rotational motion of particles on collision frequency is elucidated by comparing the ideal collision rate calculations with similar calculations for nonrotating particles. It is shown that the ratio of the collision rate of cylinders to that of spheres that circumscribe the cylinders is proportional to 1/rr(e) for r ? 1 and r(e) for r ? 1. Here, r(e) is the effective aspect ratio defined as the aspect ratio of a spheroid having the same period of rotation as the cylinder. The effective aspect ratio of the cylindrical particles was determined using finite element calculations of the torque on nonrotating cylinders with their axes parallel to the velocity and velocity gradient directions. In addition to deriving the total collision rate, we categorize collisions as side-side, edge-side, and face-edge based on the initial point of contact. Most collisions are found to be side-edge for r ? 1 and face-edge for r ? 1, suggesting that nonlinear aggregates will develop if particles stick at the point of first contact. 相似文献
88.
Vikram Singh Lalit Kumar Vinay Kumar A. K. Narula Gagan Deep 《Journal of Thermal Analysis and Calorimetry》2011,104(3):1185-1189
Curing behaviour of DGEBA was investigated in the presence of varying molar ratio of biuret and 4,4′-diaminodiphenylsulfone
(DDS) by means of Differential scanning calorimetery. The multiple heating rate method (5, 10, 15 and 20 °C min−1) was used to study the curing behaviour of epoxy resins. The peak exotherm temperature was found to be dependent on the heating
rates, structure of biuret as well as on the ratios of biuret:DDS used. Ozawa method was used for calculating the activation
energy of curing reaction. The thermal stability of the isothermally cured resins was evaluated by recording the thermogravimetric
traces in nitrogen atmosphere. All the samples were stable up to 330 °C. 相似文献
89.
Feng Zhang Li Pan Juhee Choi Vikram Mehar John T. Diulus Aravind Asthagiri Jason F. Weaver 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(47):14113-14117
Achieving selective C H bond cleavage is critical for developing catalytic processes that transform small alkanes to value‐added products. The present study clarifies the molecular‐level origin for an exceptionally strong preference for propane to dissociate on the crystalline PdO(101) surface via primary C H bond cleavage. Using reflection absorption infrared spectroscopy (RAIRS) and density functional theory (DFT) calculations, we show that adsorbed propane σ‐complexes preferentially adopt geometries on PdO(101) in which only primary C H bonds datively interact with the surface Pd atoms at low propane coverages and are thus activated under typical catalytic reaction conditions. We show that a propane molecule achieves maximum stability on PdO(101) by adopting a bidentate geometry in which a H Pd dative bond forms at each CH3 group. These results demonstrate that structural registry between the molecule and surface can strongly influence the selectivity of a metal oxide surface in activating alkane C H bonds. 相似文献
90.