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Pore Opening (pore + opening)

Distribution by Scientific Domains

Physics and Astronomy	50%
Medical Sciences	33%

Selected Abstracts

Synthesis of Rhodium Colloidal Nano-Coating Grafted Mesoporous Silica Composite and its Application as Efficient Environmentally Benign Catalyst for Heck-Type Reaction of Arylboronic Acids

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2008
Liang Li
Abstract The synthesis and characterization of rhodium colloidal layer grafted mesoporous SBA-15 material, designated as SBA-Rh, are presented. In the preparation of this new catalyst, SBA-15 mesoporous material was used as support without any pretreatment. The SiH functional groups were introduced onto the surface which resulted in highly dispersed metal colloid layer both on the outer and inner surface of the supporting material. The material was investigated for Heck-type coupling reactions of alkenes with ayboronic in organic/water solvent. The ultrahigh specific area, large pore opening, and highly dispersed catalyst species in SBA-Rh material created one of the most active heterogeneous catalysts for such reactions. Rhodium element was not detected in the final mixture by ICP after reaction. The catalyst species showed very high stability against leaching from the matrix and can be recycled for repeated use. [source]

A simple approach for synthesis of TiO2 nanotubes with through-hole morphology

PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 5 2009
Krishna Kant
Abstract The present work reports a simple approach for fabrication of self-standing titania (TiO2) nanotube membranes with through-hole morphology. The method is hydrofluoric acid free and the pore opening of TiO2 nanotubes is performed by electrochemical thinning of the oxide barrier layer. A reduction of anodization voltage was applied at the end of the anodization process to cause a successful removal of the remaining barrier layer from the TiO2 nanotubes during their detachment from the underlying titanium substrate. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Porous silicon as a cell interface for bone tissue engineering

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2007
Wei Sun
Abstract A novel cell interface has been constructed on porous silicon. We have demonstrated that nano- to macro-scale porous architectures have promising osteoconductive potentials. Macroporous silicon (pore opening 1,2 µm) is especially favorable for osteoblast adhesion, growth, protein synthesis and mineralization. An electronic/optoelectronic controllable medical implant with both scaffolding and drug delivery functions may be created for orthopaedic tissue engineering with this material. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Schisandrin B stereoisomers protect against hypoxia/reoxygenation-induced apoptosis and associated changes in the Ca2+ -induced mitochondrial permeability transition and mitochondrial membrane potential in AML12 hepatocytes

PHYTOTHERAPY RESEARCH, Issue 11 2009
Po Yee Chiu
Abstract The effects of the schisandrin B stereoisomers, (±), -schisandrin [(±), -Sch] and (,)schisandrin B [(,)Sch B], on hypoxia/reoxygenation-induced apoptosis were investigated in AML12 hepatocytes. Changes in cellular reduced glutathione (GSH) levels, Ca2+ -induced mitochondrial permeability transitions (MPTs) and mitochondrial membrane potentials (,,m values) were also examined in (±), -Sch- and (,)Sch B-treated cells, without or with hypoxia/reoxygenation challenge. The (±), -Sch/(,)Sch B pretreatments (2.5,5.0 µm) protected against hypoxia/reoxygenation-induced apoptosis in AML12 cells in a concentration-dependent manner, with the (,)Sch B effect being more potent. Drug antiapoptotic effects were further evidenced by suppression of hypoxia/reoxygenation-induced mitochondrial cytochrome c release and subsequent cleavage of caspase 3 and poly-ADP-ribose polymerase by (,)Sch B pretreatment. Whereas hypoxia/reoxygenation challenge increased the extent of Ca2+ -induced MPT pore opening, and ,,m, in AML12 hepatocytes, cytoprotection afforded by (±), -Sch/(,)Sch B pretreatment against hypoxia/reoxygenation-induced apoptosis was associated with a decreased sensitivity to Ca2+ -induced MPT and an increased ,,m in both unchallenged and challenged cells, compared with the drug-free control. The results indicate that (±), -Sch/(,)Sch B pretreatment protected against hypoxia/reoxygenation-induced apoptosis in AML12 hepatocytes and that the cytoprotection afforded by (±), -Sch/(,)Sch B may at least in part be mediated by a decrease in sensitivity to Ca2+ -induced MPT, which may in turn result from enhancement of cellular GSH levels by drug pretreatments. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Malonate induces cell death via mitochondrial potential collapse and delayed swelling through an ROS-dependent pathway

BRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2005
Francisco J Fernandez-Gomez
1Herein we study the effects of the mitochondrial complex II inhibitor malonate on its primary target, the mitochondrion. 2Malonate induces mitochondrial potential collapse, mitochondrial swelling, cytochrome c (Cyt c) release and depletes glutathione (GSH) and nicotinamide adenine dinucleotide coenzyme (NAD(P)H) stores in brain-isolated mitochondria. 3Although, mitochondrial potential collapse was almost immediate after malonate addition, mitochondrial swelling was not evident before 15 min of drug presence. This latter effect was blocked by cyclosporin A (CSA), Ruthenium Red (RR), magnesium, catalase, GSH and vitamin E. 4Malonate added to SH-SY5Y cell cultures produced a marked loss of cell viability together with the release of Cyt c and depletion of GSH and NAD(P)H concentrations. All these effects were not apparent in SH-SY5Y cells overexpressing Bcl-xL. 5When GSH concentrations were lowered with buthionine sulphoximine, cytoprotection afforded by Bcl-xL overexpression was not evident anymore. 6Taken together, all these data suggest that malonate causes a rapid mitochondrial potential collapse and reactive oxygen species production that overwhelms mitochondrial antioxidant capacity and leads to mitochondrial swelling. Further permeability transition pore opening and the subsequent release of proapoptotic factors such as Cyt c could therefore be, at least in part, responsible for malonate-induced toxicity. British Journal of Pharmacology (2005) 144, 528,537. doi:10.1038/sj.bjp.0706069 [source]

Enhanced control of porous silicon morphology from macropore to mesopore formation

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2005
Huimin Ouyang
Abstract Porous silicon (PSi) is a versatile material that possesses a wide range of morphologies. There are two main types of microstructures that are widely used and well studied: branchy mesoporous silicon with pore sizes from 10 nm to 50 nm and classical macroporous silicon with pore sizes from 500 nm to 20 µm. Much less work has been done on structures with intermediate pore sizes from 100 nm to 300 nm. Applications such as immunoassays biosensing can greatly benefit from the intermediate morphology due to the larger pore openings compared to mesopores, and increased internal surface compared to classical macropores. In this work we demonstrate well-defined macropore of 150 nm diameter in average and precise control of the porous silicon morphology transition from smooth macropores to branchy mesopores on one substrate with one electrolyte. A multilayer structure (microcavity) consisting of both mesopores and macropores is presented. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]