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排序方式: 共有195条查询结果,搜索用时 307 毫秒
81.
Ionela Cristina Nica Miruna S. Stan Roua G. Popescu Nicoleta Nicula Robert Ducu Lucian Diamandescu Anca Dinischiotu 《International journal of molecular sciences》2021,22(17)
The advancement of nanotechnology in the last decade has developed an abundance of novel and intriguing TiO2-based nanomaterials that are widely used in many sectors, including industry (as a food additive and colorant in cosmetics, paints, plastics, and toothpaste) and biomedicine (photoelectrochemical biosensing, implant coatings, drug delivery, and new emerging antimicrobial agents). Therefore, the increased use of engineered nanomaterials in the industry has raised serious concern about human exposure and their unexpected cytotoxic effects. Since inhalation is considered the most relevant way of absorbing nanomaterials, different cell death mechanisms induced in MRC-5 lung fibroblasts, following the exposure to functionalized TiO2 NPs, were investigated. Long-term exposure to TiO2 nanoparticles co-doped with 1% of iron and nitrogen led to the alteration of p53 protein activity and the gene expression controlled by this suppressor (NF-kB and mdm2), DNA damage, cell cycle disruptions at the G2/M and S phases, and lysosomal membrane permeabilization and the subsequent release of cathepsin B, triggering the intrinsic pathway of apoptosis in a Bax- and p53-independent manner. Our results are of major significance, contributing to the understanding of the mechanisms underlying the interaction of these nanoparticles with in vitro biological systems, and also providing useful information for the development of new photocatalytic nanoparticles that are active in the visible spectrum, but with increased biocompatibility. 相似文献
82.
Nicoleta Cazacu Claudia G. Chilom Melinda David Monica Florescu 《International journal of molecular sciences》2022,23(8)
Levothyroxine (LT4) is known for its use in various conditions including hypothyroidism. LT4 interaction with serum albumin may be influenced by the presence of vitamins. For this reason, we investigated the effect of vitamin C, vitamin B12, and folic acid on the complex of Bovine Serum Albumin with LT4 (BSA-LT4). UV-Vis spectroscopy was used to monitor the influence of vitamins on the BSA-LT4 complex. Fluorescence spectroscopy revealed a static quenching mechanism of the fluorescence of BSA-LT4 complex by the vitamin C and folic acid and a combined mechanism for vitamin B12. The interaction of vitamin C and folic acid with BSA-LT4 was moderate, while the binding of vitamin B12 was much stronger, extending the storage time of LT4 in blood plasma. Synchronous fluorescence found that the vitamins were closer to the vicinity of Trp than to Tyr and the effect was more pronounced for the binding of vitamin B12. The thermal stability of the BSA-LT4 complex was more evident, but no influence on the stability of BSA-LT4 complex was obtained for vitamin C. Molecular docking studies showed that vitamin C and folic acid bound the same site of the protein, while vitamin B12 bonded to a different site. 相似文献
83.
Cristiano Lazzari Gilson Wirth Fernanda Lima Kastensmidt Lorena Anghel Ricardo Augusto da Luz Reis 《Electrical Engineering (Archiv fur Elektrotechnik)》2012,94(1):11-18
This article proposes a technique to improve the dependability of circuits under energetic particle irradiation by resizing
transistors in the most critical paths. First, the SET vulnerability of a mapped circuit is analyzed to identify the most
sensitive nodes. The sensitivity of the circuit is defined by the logical and electrical masking. Once the most critical nodes
are selected, a transistor sizing algorithm is able to resize the pull-up and pull-down transistors separately. The asymmetric
resizing offers interesting area and performance trade-off in comparison with gate sizing and gate duplication techniques.
Results show very small area and performance penalties for circuits operating at ground level for a 130-nm technology process. 相似文献
84.
Marius-Gabriel Suru Adrian-Liviu Paraschiv Nicoleta Monica Lohan Bogdan Pricop Burak Ozkal Leandru-Gheorghe Bujoreanu 《Journal of Materials Engineering and Performance》2014,23(7):2669-2676
The present work reports the influence of the loading mode provided during training under constant stress, in bending, applied to lamellar specimens of Cu-Zn-Al shape memory alloys (SMAs). During training, the specimens were bent by a load fastened at their free end, while being martensitic at room temperature and they lifted the load by one-way effect (1WE), during heating up to austenitic field. On cooling to martensite field, the lower concave surface of bent specimens was compressed, and during heating it was elongated, being subjected to a series of tension-compression cycles, during heating-cooling, respectively. Conversely, the upper convex surface of bent specimens was elongated during cooling and compressed during heating, being subjected to compression-tension cycles. Furthermore, 2WE-trained actuators were tested by means of a hydraulic installation where, this time heating-cooling cycles were performed in oil conditions. Considering that the lower concave surface of the specimens was kept in compressed state, while the upper convex surface was kept in elongated state, the study reveals the influence of the two loading modes and environments on the width of martensite plates of the specimens trained under various numbers of cycles. In this purpose, Cu-Zn-Al specimens, trained under 100-300-500 cycles, were prepared and analyzed by atomic force microscopy (AFM) as well as optical and scanning electron microscopy (OM and SEM, respectively). The analysis also included AFM micrographs corroborated with statistical evaluations in order to reveal the effects of loading mode (tension or compression) in different environmental conditions of the specimens, on the surface profile characteristics of martensite plates, revealed by electropolishing. 相似文献
85.
86.
Laura Corpaş Nicoleta G. Hădărugă Ioan David Paul Pîrşan Daniel I. Hădărugă Heinz-Dieter Isengard 《Food Analytical Methods》2014,7(6):1353-1358
In this research, a new Karl Fischer water titration–principal component analysis (KFT–PCA) concept on wheat flour samples was introduced and studied. First, the evaluation of the performance of the determination of water content of wheat flour (Triticum aestivum L. subsp. aestivum) by using the KFT method was performed. The water content of white wheat flour, determined by KFT method, was in the range of 14.9–15.2 %, while for the whole-wheat and Graham flour samples, this concentration was lower (14.7 and 14.5 %, respectively) and was close to the limit of Romanian standards. The new approach on the KFT water reaction rates for wheat flour was performed. Thus, the “surface water” reaction rates of 1.2–2.1 mM/s and the “strongly bound water” reaction rates of 0.13–0.24 mM/s were obtained for flour samples. Further, these water reaction rates together with the primary KFT parameters (e.g., water concentration and normalized titration volume) were used in a multivariate statistical approach (PCA) in order to evaluate similarities–dissimilarities between samples. Among KFT parameters, the water content, the normalized titration volume, and the surface water reaction rate were important for a good classification of the flour products. 相似文献
87.
88.
This paper describes a way to create a cleanroom environment with a limited budget, which may be useful to organizations requiring small amounts of very high quality surface processing. After a brief review of some general principles, it discusses the design, including practical constraints, and installation of a small facility in the University of Warwick. Based around standard bought-in items, it achieves cleanroom Class 10 000 (ISO Class 7) with local enclosures of better than Class 10 (ISO Class 4) air quality. 相似文献
89.
The paper refers to the concerns that have existed ever since 1982 in the Institute of Scientific Research and Technological Engineering for Power Equipment (ICSITEE)-Bucharest to utilize power units to convert wind energy into electric power (WEU).
The paper describes test patterns and industrial pilots for WEU of 10, 30, 50 and 300 kW achieved by the Center of Scientific Research and Technological Engineering for Hydropower Equipment (CCSITEH) Re i a-Timi oara Division. 相似文献
90.
Denis Mihaela Panaitescu Cristian Andi Nicolae Adriana Nicoleta Frone Ioana Chiulan Paul Octavian Stanescu Constantin Draghici Michaela Iorga Mona Mihailescu 《应用聚合物科学杂志》2017,134(19)
The widespread application of poly(3‐hydroxybutyrate) (PHB) in the food packaging and biomedical fields has been hindered by its high brittleness, slow crystallization, poor thermal stability, and narrow processing window. To overcome these limitations, a mixture of biodegradable and biocompatible plasticizers was used to modify PHB. Epoxidized soybean oil (ESO), acetyl tributyl citrate, poly(ethylene glycol) 4000 (PEG4000), and poly(ethylene glycol) 6000 (PEG6000) were tested to improve PHB melt processing and to achieve balanced thermal and mechanical properties. These plasticizers increased the flexibility and decreased the melt viscosity, improving the processability. The tensile strength was maintained within the limit of experimental error for ESO and decreased slightly (6–7%) for the other plasticizers. PEG6000 and ESO delayed the decomposition process of PHB. The plasticizers did not hinder the crystallization, and poly(ethylene glycol)s increased the crystallinity. The change in the interplanar distance and crystallite size, correlated with lamellar stack dimensions, gave more information on the plasticizers' effects in PHB. The blend with 5 wt % ESO was considered suitable for the fabrication of marketable PHB films. This study showed that it is possible to tailor the rheological, thermal, and mechanical behavior of a commercial PHB through the addition of a second plasticizer. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44810. 相似文献