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991.
Ana C. Marques Himanshu Jain Carol Kiely Kai Song Christopher J. Kiely Rui M. Almeida 《Journal of Sol-Gel Science and Technology》2009,51(1):42-47
Development of optimal scaffolds for bone tissue engineering and regeneration is still a challenge, since many materials and
structures have been proposed but few have reached clinical expectations. This work reports on the preparation and characterization
of SiO2-CaO and SiO2-CaO-P2O5 sol–gel derived monoliths, with potential application as glass scaffolds for bone regeneration, exhibiting a nano/macro trimodal
pore size distribution, including pores of ~100’s of micrometers (μm), several microns and just a few nanometers (nm) in size.
Interconnected macropores (~20–200 μm) have been obtained in the present work by polymerization-induced spinodal phase separation
along with the sol–gel transition, when a water soluble polymer [poly(ethylene oxide)] was added to the sol–gel solution;
the several-micron pores are spherical and isolated and might be the result of secondary phase separation by nucleation-growth
mechanism; the interconnected nanopore (~5–25 nm) structure of the macroporous gel skeleton, on the other hand, was tailored
by solvent exchange procedures. The morphological and textural characterization of these materials was performed by scanning
electron microscopy (SEM), transmission electron microscopy (TEM), X-ray ultra microscopy (XuM), nitrogen adsorption and mercury
intrusion porosimetry. The factors affecting the porosity exhibited by the scaffolds, such as glass composition and solvent
exchange conditions, have been assessed.
相似文献
Ana C. MarquesEmail: |
992.
Ming‐Dong Zhou Yang Yu Alejandro Capap KavitaR. Jain Eberhardt Herdtweck Xiao‐Rong Li Jun Li Shu‐Liang Zang FritzE. Kühn 《化学:亚洲杂志》2009,4(3):411-418
It′s a fine line : Methyltrioxorhenium(VII) (MTO) readily forms 1:1 adducts with several N‐(salicylidene)aniline derived Schiff bases. Steric and electronic effects of the ligands play a major role when it comes to stability and catalytic activity. Good donors on the Schiff base ligands, in general, lead to shorter Re? O(Schiff base) bridges and lower catalytic activity, while it is the opposite for acceptor ligands on the Schiff bases.
993.
994.
Santosh Kumar Rai Meena Sharma Madhu Jain Abhishek Awasthi Dharmendra Kumar Purshottam Narayanan Kuttanpillai Nair Ashok Kumar Sharma 《Applied biochemistry and biotechnology》2010,162(7):1929-1937
An efficient in vitro process for rapid production of cloned plants of Uraria picta has been developed employing nodal stem segments taken from field-grown plants. Explants showed bud-break followed by regeneration
of shoots with restricted growth within 12 days on modified Murashige and Skoog’s medium supplemented with 0.25 mg l–1 each of 6-benzylaminopurine and indole-3-acetic acid and 25 mg l-1 adenine sulfate. Normal growth of shoots with good proliferation rate was achieved by reducing the concentrations of 6-benzylaminopurine
and indole-3-acetic acid to 0.1 mg l-1 each and incorporating 0.5 mg l-1 gibberellic acid in the medium in which, on an average, 19.6 shoots per explant were produced. Further, during successive
subcultures, increased concentrations of adenine sulfate (50 mg l-l) and gibberellic acid (2 mg l-l) along with the addition of 20 mg l-l
dl-tryptophan were found conducive to control the problem of necrosis of shoots. In this treatment, several “crops” of shoots
were obtained from single culture by repeated subculturing of basal portion of stalk in long-term. Isolated shoots rooted
100% in 0.25 mg l-1 indole-3-butyric acid. In vitro-raised plants after hardening in inorganic salt solution grew normally in soil and came to
flowering. Genetic fidelity of in vitro-raised plants was ascertained by rapid amplified polymorphic DNA (RAPD) markers. Also,
quantitative estimation of two isoflavonones in their root extracts further confirmed true-to-type nature of plantlets. 相似文献
995.
Ajay N. Jain 《Journal of computer-aided molecular design》2010,24(10):865-878
Computational methods for predicting ligand affinity where no protein structure is known generally take the form of regression
analysis based on molecular features that have only a tangential relationship to a protein/ligand binding event. Such methods
have utility in retrospective rationalization of activity patterns of substituents on a common scaffold, but are limited when
either multiple scaffolds are present or when ligand alignment varies significantly based on structural changes. In addition,
such methods generally assume independence and additivity of effect from scaffold substituents. Collectively, these non-physical
modeling assumptions sharply limit the utility of widely used QSAR approaches for prospective prediction of ligand activity.
The recently introduced Surflex-QMOD approach, by virtue of constructing physical models of binding sites, comes closer to
a modeling approach that is congruent with protein ligand binding events. A set of congeneric CDK2 inhibitors showed that
induced binding pockets can be quite congruent with the enzyme’s active site but that model predictivity within a chemical
series does not necessarily depend on congruence. Muscarinic antagonists were used to show that the QMOD approach is capable
of making accurate predictions in cases where highly non-additive structure activity effects exist. The QMOD method offers
a means to go beyond non-causative correlations in QSAR analysis. 相似文献
996.
The paper describes linear and nonlinear modeling of the wastewater data for the performance evaluation of an up-flow anaerobic sludge blanket (UASB) reactor based wastewater treatment plant (WWTP). Partial least squares regression (PLSR), multivariate polynomial regression (MPR) and artificial neural networks (ANNs) modeling methods were applied to predict the levels of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) in the UASB reactor effluents using four input variables measured weekly in the influent wastewater during the peak (morning and evening) and non-peak (noon) hours over a period of 48 weeks. The performance of the models was assessed through the root mean squared error (RMSE), relative error of prediction in percentage (REP), the bias, the standard error of prediction (SEP), the coefficient of determination (R2), the Nash-Sutcliffe coefficient of efficiency (Ef), and the accuracy factor (Af), computed from the measured and model predicted values of the dependent variables (BOD, COD) in the WWTP effluents. Goodness of the model fit to the data was also evaluated through the relationship between the residuals and the model predicted values of BOD and COD. Although, the model predicted values of BOD and COD by all the three modeling approaches (PLSR, MPR, ANN) were in good agreement with their respective measured values in the WWTP effluents, the nonlinear models (MPR, ANNs) performed relatively better than the linear ones. These models can be used as a tool for the performance evaluation of the WWTPs. 相似文献
997.
998.
Zarah Walsh Pavel A. Levkin Vijay Jain Brett Paull Frantisek Svec Mirek Macka 《Journal of separation science》2010,33(1):61-66
Poly(styrene‐co‐divinylbenzene) monolithic stationary phases have been synthesized for the first time by photoinitiated polymerization. An initiator composed of (+)‐(S)‐camphorquinone/ethyl‐4‐dimethylaminobenzoate/N‐methoxy‐4‐phenylpyridinium tetrafluoroborate was activated using a 470 nm light emitting diode array as the light source. Spatially controlled polymerization of styrenic monoliths has been achieved within specific sections of a 100 μm id polytetrafluoroethylene‐coated fused‐silica capillary using simple photo masking. The sharpness of the edges was confirmed by optical microscopy, while SEM was used to verify a typical porous, globular morphology. Flow resistance data were used to assess the permeability of the monoliths and they were found to have good flow through properties with a flow resistance of 0.725 MPa/cm at 1 μL/min (water, 20°C). Conductivity profiling along the length of the capillary was used to assess their lateral homogeneity. Monoliths which were axially rotated during polymerization were found to be homogeneous along the whole length of the capillary. The monolithic stationary phases were applied to the RP gradient separation of a mixture of proteins. Column fabrication showed excellent reproducibility with the retention factor (k) having a RSD value of 2.6% for the batch and less than 1.73% on individual columns. 相似文献
999.
Gene silencing using RNA interference (RNAi) has become a prominent biological tool for gene annotation, pathway analysis, and target discovery in mammalian cells. High-throughput screens conducted using whole-genome siRNA libraries have uncovered rich sets of new genes involved in a variety of biological processes and cellular models of disease. However, high-throughput RNAi screening is not yet a mainstream tool in life science research because current screening platforms are expensive and onerous. Miniaturizing the RNAi screening platform to reduce cost and increase throughput will enable its widespread use and harness its potential for rapid genome annotation. With this aim, we have combined semi-conductor microfabrication and nanolitre dispensing techniques to develop miniaturized electroporation-ready microwell arrays loaded with siRNA molecules in which multiplexed gene knockdown can be achieved. Arrays of microwells are created using high-aspect ratio biocompatible photoresists on optically transparent and conductive Indium-Tin Oxide (ITO) substrates with integrated micro-electrodes to enable in situ electroporation. Non-contact inkjet microarraying allows precise dispensing of nanolitre volumes into the microwell structures. We have achieved parallel electroporation of multiple mammalian cells cultured in these microwell arrays and observed efficient knockdown of genes with surface-bound, printed siRNAs. Further integration of microfabrication and non-contact nanolitre dispensing techniques described here may enable single-substrate whole-genome siRNA screening in mammalian cells. 相似文献
1000.
Bharti Khungar Madharam Sudershan Rao Kasiviswanadharaju Pericherla Pankaj Nehra Navin Jain Jitendra Panwar Anil Kumar 《Comptes Rendus Chimie》2012,15(8):669-674
The synthesis of novel imidazolium ionic liquid, tagged Schiff, has been described. The synthesis was achieved in three steps from 2,4-dihydroxybenzaldehyde by selective alkylation with 1,3-dibromopropane, followed by reaction with 1-methylimidazole and Schiff base formation with aromatic amines. The compounds were evaluated for antibacterial and antifungal activities. The ionic liquid tagged Schiff base 4a showed the inhibition of both Gram positive and Gram negative bacteria. It also showed broad spectrum antifungal activity against all four tested fungi; however, 4f showed highest antifungal activity against A. niger. 相似文献