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排序方式: 共有5727条查询结果,搜索用时 15 毫秒
931.
Snia I. G. Fangaia Pedro M. G. Nicolau Fernando A. D. R. A. Guerra M. Melia Rodrigo Gianluca Utzeri Ana M. T. D. P. V. Cabral Artur J. M. Valente Miguel A. Esteso Ana C. F. Ribeiro 《International journal of molecular sciences》2021,22(24)
Metal ions such as cobalt (II) and chromium (III) might be present in the oral cavity, as a consequence of the corrosion of Co-Cr dental alloys. The diffusion of such metal ions into the organism, carried by saliva, can cause health problems as a consequence of their toxicity, enhanced by a cumulative effect in the body. The effect of the chlorhexidine digluconate, which is commonly used in mouthwash formulations, on the transport of these salts is evaluated in this paper by using the Taylor dispersion technique, which will allow an assessment of how the presence of chlorhexidine digluconate (either in aqueous solution or in a commercial formulation) may affect the diffusion of metal ions. The ternary mutual diffusion coefficients of metal ions (Co and Cr) in the presence of chlorhexidine digluconate, in an artificial saliva media, were measured. Significant coupled diffusion of CoCl2 (and CrCl3) and chlorhexidine digluconate is observed by analysis of the non-zero values of the cross-diffusion coefficients, D12 and D21. The observed interactions between metal ions and chlorhexidine digluconate suggest that the latter might be considered as an advantageous therapeutic agent, once they contribute to the reduction of the concentration of those ions inside the mouth. 相似文献
932.
Ana M Castrilln Pilar Navarro Esther Alvrez-Pontes 《Journal of the science of food and agriculture》1997,75(1):125-132
Modifications in proximate composition, fatty acids, amino acids and –SH groups content, as well as changes in solubility and nutritional quality of protein, were studied in fillets of sardine (Clupea pilchardus) that had been successively pan-fried, frozen stored and reheated by two different means, namely conventional oven and microwave oven. Upon pan-frying in olive oil the sardine absorbed C18: 1(n-9) and C18: 2(n-6) and lost saturated (SFA) and polyunsaturated fatty acids (PUFA); this loss continued upon reheating, and as a consequence the percentage of MUFA increased compared to the just-fried sardine. A loss of water was observed during all processes. Upon frying there was a decrease of cyst(e)ine. Upon reheating by both microwave and conventional oven, methionine decreased; however, cyst(e)ine only decreased with the use of a conventional oven. A loss of –SH groups was recorded during frying and this phenomenon continued upon reheating. Biological value (BV) together with net protein utilisation (NPU) decreased upon both frying and reheating. © 1997 SCI. 相似文献
933.
934.
Andoni Rodriguez-Abetxuko Elena Romero-Ben Aitor Ontoria Marcos Heredero Beatriz Martín-García Krishan Kumar Sergio Martín-Saldaña Felipe Conzuelo Ana Beloqui 《Advanced functional materials》2024,34(18):2400479
The inorganic content and the catalytic performance pose metal-loaded enzyme nanoflowers as promising candidates for developing bioelectrodes capable of functioning without the external addition of a redox mediator. However, these protein-inorganic hybrids have yet to be successfully applied in combination with electrode materials. Herein, the synthesis procedure of these bionanomaterials is reproposed to precisely control the morphology, composition, and performance of this particular protein-mineral hybrid, formed by glucose oxidase and cobalt phosphate. This approach aims to enhance the adherence and electron mobility between the enzyme and a carbon electrode. The strategy relies on dressing the protein in a tailored thin nanogel with multivalent chemical motifs. The functional groups of the polymer facilitate the fast protein sequence-independent biomineralization. Furthermore, the engineered enzymes enable the fabrication of robust cobalt-loaded enzyme inorganic hybrids with exceptional protein loads, exceeding 90% immobilization yields. Notably, these engineered biohybrids can be readily deposited onto flat electrode surfaces without requiring chemical pre-treatment. The resulting bioelectrodes are robust and exhibit electrochemical responses even without the addition of a redox mediator, suggesting that cobalt complexes promote electron wiring between the active site of the enzyme and the electrode. 相似文献
935.
Ana M Azevedo Luís P Fonseca Duarte M
F Prazeres 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1999,74(11):1110-1116
The stability of an oligomeric enzyme, penicillin acylase, was studied in aqueous media. The enzyme was produced by mutant cells of Escherichia coli ATCC 9637, extracted from the periplasmic space by osmotic shock and further purified using a pseudo‐affinity adsorption process. Enzyme stabilisation attempts were performed with salts, alcohols and sugars. The highest levels of retained activity were obtained in the presence of 15% (w/v) ammonium or sodium sulfate. A kinetic model was proposed to describe the inactivation of penicillin acylase, taking into account results obtained in stability assays performed at different temperatures and with different enzyme concentrations. According to this model, the inactivation of penicillin acylase involves an intermediary active precursor of the enzyme, formed prior to dissociation into sub‐units. © 1999 Society of Chemical Industry 相似文献
936.
Ana María Sastre Abdelhay Madi Jos Luis Cortina Francisco Jos Alguacil 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1999,74(4):310-314
The extraction of gold(I) from aurocyanide aqueous solutions using LIX 79 has been studied. Different variables that could affect the extraction system were evaluated: equilibration time, aqueous pH, metal and extractant concentrations, organic phase diluent and aqueous ionic strength. The extraction of the aurocyanide complex with respect to other metal‐cyano complexes has also been studied on both synthetic and real leach solutions. Gold experimental data have been analysed numerically to determine the stoichiometry of extracted species and its equilibrium constant. It was found that gold(I) was extracted into the organic phase by the formation of the species RHAu(CN)2 (LIX 79=R). Stripping of gold from loaded organic phases was carried out using NaOH or NaCN solutions. © 1999 Society of Chemical Industry 相似文献
937.
Ana S. Serras Srgio P. Cames Bernardo Antunes Vera M. Costa Flvio Dionísio Volkan Yazar Rui Vitorino Fernando Remio Matilde Castro Nuno G. Oliveira Joana P. Miranda 《International journal of molecular sciences》2021,22(23)
Doxorubicin (Dox) is one of the most widely used treatments for breast cancer, although limited by the well-documented cardiotoxicity and other off-target effects. Mesenchymal stem cell (MSC) secretome has shown immunomodulatory and regenerative properties, further potentiated under 3D conditions. This work aimed to uncover the effect of the MSC-derived secretome from 3D (CM3D) or 2D (CM2D) cultures, in human malignant breast cells (MDA-MB-231), non-tumor breast epithelial cells (MCF10A) and differentiated AC16 cardiomyocytes, co-treated with Dox. A comprehensive proteomic analysis of CM3D/CM2D was also performed to unravel the underlying mechanism. CM3D/CM2D co-incubation with Dox revealed no significant differences in MDA-MB-231 viability when compared to Dox alone, whereas MCF10A and AC16 viability was consistently improved in Dox+CM3D-treated cells. Moreover, neither CM2D nor CM3D affected Dox anti-migratory and anti-invasive effects in MDA-MB-231. Notably, Ge-LC-MS/MS proteomic analysis revealed that CM3D displayed protective features that might be linked to the regulation of cell proliferation (CAPN1, CST1, LAMC2, RANBP3), migration (CCN3, MMP8, PDCD5), invasion (TIMP1/2), oxidative stress (COX6B1, AIFM1, CD9, GSR) and inflammation (CCN3, ANXA5, CDH13, GDF15). Overall, CM3D decreased Dox-induced cytotoxicity in non-tumor cells, without compromising Dox chemotherapeutic profile in malignant cells, suggesting its potential use as a chemotherapy adjuvant to reduce off-target side effects. 相似文献
938.
939.
940.
Forti FL Bet MR Goissis G Plepis AM 《Journal of materials science. Materials in medicine》2011,22(8):1901-1912
Polyanionic collagen obtained from bovine pericardial tissue submitted to alkaline hydrolysis is an acellular matrix with
strong potential in tissue engineering. However, increasing the carboxyl content reduces fibril formation and thermal stability
compared to the native tissues. In the present work, we propose a chemical protocol based on the association of alkaline hydrolysis
with 1,4-dioxane treatment to either attenuate or revert the drastic structural modifications promoted by alkaline treatments.
For the characterization of the polyanionic membranes treated with 1,4-dioxane, we found that (1) scanning electron microscopy
(SEM) shows a stronger reorientation and aggregation of collagen microfibrils; (2) histological evaluation reveals recovering
of the alignment of collagen fibers and reassociation with elastic fibers; (3) differential scanning calorimetry (DSC) shows
an increase in thermal stability; and (4) in biocompatibility assays there is a normal attachment, morphology and proliferation
associated with high survival of the mouse fibroblast cell line NIH3T3 in reconstituted membranes, which behave as native
membranes. Our conclusions reinforce the ability of 1,4-dioxane to enhance the properties of negatively charged polyanionic
collagen associated with its potential use as biomaterials for grafting, cationic drug- or cell-delivery systems and for the
coating of cardiovascular devices. 相似文献