The Experts below are selected from a list of 18 Experts worldwide ranked by ideXlab platform

Kilic A.m. - One of the best experts on this subject based on the ideXlab platform.

  • New lightweight colemanite-added perlite brick and comparison of its Physicomechanical properties with other commercial lightweight materials
    'Elsevier BV', 2014
    Co-Authors: Celik A.g., Depci T., Kilic A.m.
    Abstract:

    Lightweight bricks can be produced by mixing the expanded perlite, CMC, coal dust and water. However, it may not achieve some of the Physicomechanical properties. Therefore, colemanite is chosen in the present study to obtain lightweight bricks with high strength, heat and sound insulating and neutron shielding properties in the field of construction. The bricks were prepared by using different amount of colemanite (0-20% by weight) at different temperatures (200-400 °C). Optimum Physicomechanical Property of the brick was obtained after the heat treatment at 400°C when 10% colemanite was added into the brick. Its Physicomechanical properties (compressive strength, point loading index, unit weight, ultrasonic transit speed, water adsorption, porosity, heat and sound conductivity and sound insulation and neutron shielding effectiveness) were compared with the commercial lightweight construction bricks (normal brick, sandwich brick, gas concrete and pumice block). Our results indicated that brick studied in this article had better physical properties than the other construction bricks. © 2014 Elsevier Ltd. All rights reserved.BOREN-2008-B0201This work is supported by National Boron Research Institute (BOREN) via project number BOREN-2008-B0201

Nokhodchi Ali - One of the best experts on this subject based on the ideXlab platform.

  • Improvement of Physicomechanical properties of carbamazepine by recrystallization at different pH values
    'Walter de Gruyter GmbH', 2009
    Co-Authors: Javadzadeh Yousef, Mohammadi Ameneh, Khoei Nazaninossadat, Nokhodchi Ali
    Abstract:

    The morphology of crystals has an appreciable impact role on the physicochemical properties of drugs. Drug properties such as flowability, dissolution, hardness and bioavailability may be affected by crystallinity behaviours of drugs. The objective of this study was to achieve an improved Physicomechanical Property of carbamazepine powder through recrystallization from aqueous solutions at different pH values. For this purpose, carbamazapine was recrystallized from aqueous solutions at different pH values (1, 7, 11). The morphology of crystals was investigated using scanning electron microscopy; X-ray powder diffraction (XRPD) was used to identify polymorphism; thermodynamic properties were analyzed using differential scanning calorimetery (DSC). Dissolution rate was determined using USP dissolution apparatus. Mechanical behavior of recrystallized carbamazepine powders was investigated by making tablets under different compaction pressure and measuring their hardness. SEM studies showed that the carbamazepine crystallization in different media affected the morphology and size of carbamazepine crystals. The shape of carbamazepine crystals changed from flaky or thin plate-like to needle shape. XRPD and DSC results ruled out any crystallinity changes occurring due to the temperature during recrystallization procedure or pH of crystallization media. The crushing strength of tablets indicated that all of the recrystallized carbamazepine samples had better compactiblity than the original carbamazepine powder. In vitro dissolution studies of carbamazepine samples showed a higher dissolution rate for carbamazepine crystals obtained from media with pH 11 and 1. Carbamazepine particles recrystallized from aqueous solutions of different pH values (all media) appeared to have superior mechanical properties to those of the original carbamazepine sample

Evans J S - One of the best experts on this subject based on the ideXlab platform.

  • A kinetic molecular model of the reversible unfolding and refolding of titin under force extension.
    1999
    Co-Authors: Zhang B, Xu G, Evans J S
    Abstract:

    Molecular elasticity is a Physicomechanical Property that is associated with a select number of polypeptides and proteins, such as the giant muscle protein, titin, and the extracellular matrix protein, tenascin. Both proteins have been the subject of atomic force microscopy (AFM), laser tweezer, and other in vitro methods for examining the effects of force extension on the globular (FNIII/Ig-like) domains that comprise each protein. In this report we present a time-dependent method for simulating AFM force extension and its effect on FNIII/Ig domain unfolding and refolding. This method treats the unfolding and refolding process as a standard three-state protein folding model (U right arrow over left arrow T right arrow over left arrow F, where U is the unfolded state, T is the transition or intermediate state, and F is the fully folded state), and integrates this approach within the wormlike chain (WLC) concept. We simulated the effect of AFM tip extension on a hypothetical titin molecule comprised of 30 globular domains (Ig or FNIII) and 25% Pro-Glu-Val-Lys (PEVK) content, and analyzed the unfolding and refolding processes as a function of AFM tip extension, extension rate, and variation in PEVK content. In general, we find that the use of a three-state protein-folding kinetic-based model and the implicit inclusion of PEVK domains can accurately reproduce the experimental force-extension curves observed for both titin and tenascin proteins. Furthermore, our simulation data indicate that PEVK domains exhibit extensibility behavior, assist in the unfolding and refolding of FNIII/Ig domains in the titin molecule, and act as a force "buffer" for the FNIII/Ig domains, particularly at low and moderate extension forces

Evans, John Spencer - One of the best experts on this subject based on the ideXlab platform.

  • A Kinetic Molecular Model of the Reversible Unfolding and Refolding of Titin Under Force Extension
    The Biophysical Society. Published by Elsevier Inc., 1999
    Co-Authors: Bo Zhang, Xu Guangzhao, Evans, John Spencer
    Abstract:

    AbstractMolecular elasticity is a Physicomechanical Property that is associated with a select number of polypeptides and proteins, such as the giant muscle protein, titin, and the extracellular matrix protein, tenascin. Both proteins have been the subject of atomic force microscopy (AFM), laser tweezer, and other in vitro methods for examining the effects of force extension on the globular (FNIII/Ig-like) domains that comprise each protein. In this report we present a time-dependent method for simulating AFM force extension and its effect on FNIII/Ig domain unfolding and refolding. This method treats the unfolding and refolding process as a standard three-state protein folding model (U ⇆ T ⇆ F, where U is the unfolded state, T is the transition or intermediate state, and F is the fully folded state), and integrates this approach within the wormlike chain (WLC) concept. We simulated the effect of AFM tip extension on a hypothetical titin molecule comprised of 30 globular domains (Ig or FNIII) and 25% Pro-Glu-Val-Lys (PEVK) content, and analyzed the unfolding and refolding processes as a function of AFM tip extension, extension rate, and variation in PEVK content. In general, we find that the use of a three-state protein-folding kinetic-based model and the implicit inclusion of PEVK domains can accurately reproduce the experimental force-extension curves observed for both titin and tenascin proteins. Furthermore, our simulation data indicate that PEVK domains exhibit extensibility behavior, assist in the unfolding and refolding of FNIII/Ig domains in the titin molecule, and act as a force “buffer” for the FNIII/Ig domains, particularly at low and moderate extension forces

Ali Nokhodchi - One of the best experts on this subject based on the ideXlab platform.

  • Improvement of Physicomechanical properties of carbamazepine by recrystallization at different pH values
    2009
    Co-Authors: Yousef Javadzadeh, Ameneh Mohammadi, Nazaninossadat Seyed Khoei, Ali Nokhodchi
    Abstract:

    The morphology of crystals has an appreciable impact role on the physicochemical properties of drugs. Drug properties such as flowability, dissolution, hardness and bioavailability may be affected by crystallinity behaviours of drugs. The objective of this study was to achieve an improved Physicomechanical Property of carbamazepi-ne powder through recrystallization from aqueous solu-tions at different pH values. For this purpose, carbama-zapine was recrystallized from aqueous solutions at different pH values (1, 7, 11). The morphology of crystals was investigated using scanning electron microscopy; X-ray powder diffraction (XRPD) was used to identify polymor-phism; thermodynamic properties were analyzed using differential scanning calorimetery (DSC). Dissolution ra-te was determined using USP dissolution apparatus. Me