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排序方式: 共有2621条查询结果,搜索用时 859 毫秒
1.
Anna Stasiowicz Natalia Rosiak Ewa Tykarska Maciej Kozak Jacek Jenczyk Piotr Szulc Joanna Kobus-Cisowska Kornelia Lewandowska Anita Paziska Wojciech Paziski Judyta Cielecka-Piontek 《International journal of molecular sciences》2021,22(8)
Piperine is an alkaloid that has extensive pharmacological activity and impacts other active substances bioavailability due to inhibition of CYP450 enzymes, stimulation of amino acid transporters and P-glycoprotein inhibition. Low solubility and the associated low bioavailability of piperine limit its potential. The combination of piperine with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) causes a significant increase in its solubility and, consequently, an increase in permeability through gastrointestinal tract membranes and the blood–brain barrier. X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) were used to characterize interactions between piperine and HP-β-CD. The observed physicochemical changes should be combined with the process of piperine and CD system formation. Importantly, with an increase in solubility and permeability of piperine as a result of interaction with CD, it was proven to maintain its biological activity concerning the antioxidant potential (2,2-diphenyl-1-picryl-hydrazyl-hydrate assay), inhibition of enzymes essential for the inflammatory process and for neurodegenerative changes (hyaluronidase, acetylcholinesterase, butyrylcholinesterase). 相似文献
2.
Nelaka Govinna Papatya Kaner Davette Ceasar Anita Dhungana Cody Moers Katherine Son Ayse Asatekin Peggy Cebe 《Polymer International》2019,68(2):231-239
Nonwoven super‐hydrophobic fiber membranes have potential applications in oil–water separation and membrane distillation, but fouling negatively impacts both applications. Membranes were prepared from blends comprising poly(vinylidene fluoride) (PVDF) and random zwitterionic copolymers of poly(methyl methacrylate) (PMMA) with sulfobetaine methacrylate (SBMA) or with sulfobetaine‐2‐vinylpyridine (SB2VP). PVDF imparts mechanical strength to the membrane, while the copolymers enhance fouling resistance. Blend composition was varied by controlling the PVDF‐to‐copolymer ratio. Nonwoven fiber membranes were obtained by electrospinning solutions of PVDF and the copolymers in a mixed solvent of N,N‐dimethylacetamide and acetone. The PVDF crystal phases and crystallinities of the blends were studied using wide‐angle X‐ray diffraction and differential scanning calorimetry (DSC). PVDF crystallized preferentially into its polar β‐phase, though its degree of crystallinity was reduced with increased addition of the random copolymers. Thermogravimetry (TG) showed that the degradation temperatures varied systematically with blend composition. PVDF blends with either copolymer showed significant increase of fouling resistance. Membranes prepared from blends containing 10% P(MMA‐ran‐SB2VP) had the highest fouling resistance, with a fivefold decrease in protein adsorption on the surface, compared to homopolymer PVDF. They also exhibited higher pure water flux, and better oil removal in oil–water separation experiments. © 2018 Society of Chemical Industry 相似文献
3.
Yang Chao-Tung Chen Shuo-Tsung Liu Jung-Chun Chan Yu-Wei Chen Chien-Chih Verma Vinod Kumar 《The Journal of supercomputing》2019,75(8):4408-4429
The Journal of Supercomputing - In the last decade, cloud computing has brought enormous changes to people’s lives. Cloud computing gives a client-driven computational model. In this case,... 相似文献
4.
In India, little attention has been paid on antimicrobial resistance (AMR) in the context of developing “One Health” approach. Hence, utilizing multi-disciplinary approach, we assess the AMR level and dynamics/pattern of multi-drug resistance (MDR) in Escherichia coli, Salmonella spp., and Staphylococcus aureus circulating over the different stages of poultry in India. A total of 342 isolates including E. coli (n = 143), Salmonella spp. (n = 104), and S. aureus (n = 95) were recovered from fecal (n = 80) and cecal (n = 80) samples of chicken, collected across the different poultry-retail shops and poultry-farms located at urban and rural areas of Rajasthan, India, respectively. High rates of AMR to drugs that are critically/highly important both in human and veterinary medicine were observed among all the isolates. Upward trends in AMR prevalence was observed in poultry-retail shops than in poultry-farms. Notably, >90% of all the isolates were MDR, of particular, pattern/prevalence of MDR was substantially varied across the poultry-farms vs. poultry-retail shops. Our results indicate AMR including MDR to be common in E. coli, Salmonella spp., and S. aureus distributed frequently in poultry. The study encourages the formulation of national policy, programmes and further research with a “One Health” approach that can benefits to the human/animal and the environment. 相似文献
5.
DeLongis Anita; Capreol Martha; Holtzman Susan; O'Brien Tess; Campbell Jennifer 《Canadian Metallurgical Quarterly》2004,18(3):470
In response to recent calls in the literature for within-person examinations of social support processes over time, this study explores the relationships of spousal support, spousal strain, and well-being among husbands and wives, both within the same day and across days. Eighty-three couples were interviewed and completed a structured diary twice daily for 1 week. The results of multilevel hierarchical modeling suggest that both spousal support and spousal strain made significant, independent contributions to concurrent negative affect, although only spousal support was a significant predictor of next-day negative affect. Spousal strain interacted with spousal support to predict next-day negative affect. Direct and moderating effects of perceived marital adjustment on negative affect were discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
Jon T. Carter Paul E. Krajewski Ravi Verma 《JOM Journal of the Minerals, Metals and Materials Society》2008,60(11):77-81
The hot blow forming of magnesium sheet offers significant opportunity for forming complex, lightweight parts for automotive
applications. This paper characterizes the elevated-temperature formability of AZ31 magnesium sheet materials and the effect
of processing conditions on the performance of these materials. In addition, magnesium sheet application development at General
Motors Corporation is reviewed. 相似文献
7.
The application of micro- and nanofabrication processes to the development of hybrid synthetic and biological systems may enable the production of new devices such as controllable transporters, gears, levers, micropumps, or microgenerators powered by biological molecular motors. However, engineering these hybrid devices requires fabrication processes that are compatible with biological materials such as kinesin motor proteins and microtubules. In this paper, the effects of micro- and nanofabrication processing chemicals and resists on the functionality of casein, kinesin, and microtubule proteins are systematically examined to address the important missing link of the biocompatibility of micro- and nanofabrication processes needed to realize hybrid system fabrication. It is found that both casein, which is used to prevent motor denaturation on surfaces, and kinesin motors are surprisingly tolerant of most of the processing chemicals examined. Microtubules, however, are much more sensitive. Exposure to the processing chemicals leads to depolymerization, which is partially attributed to the pH of the solutions examined. When the chemicals were diluted in aqueous buffers, a subset of them no longer depolymerized microtubules and in their diluted forms still worked as resist removers. This approach broadens the application of micro- and nanofabrication processes to hybrid synthetic and biological system fabrication. 相似文献
8.
The increasing complecity of many expert system application areas calls for the integration of the knowledge of multiple experts. The use of multiple experts introduces some interesting new problems during the process of knowledge acquisition. The problems are further complicated when the experts are geographically dispersed or unavailable for face-to-face interactions.
This article discusses the motivations for acquiring the knowledge of multiple experts, the problems related to knowledge acquisition, new issues that arise whens multiple experts interact, solutions that can be brought to bear in building multiple expert systems (particularly when experts are geographically dispersed), and new tools for knowledge engineers to use when dealing with multiple experts. 相似文献
9.
Practical Equivalent Continuum Model for Simulation of Jointed Rock Mass Using FLAC3D 总被引:1,自引:0,他引:1
A simple practical equivalent continuum numerical model for simulating the behavior of jointed rock mass has been extended to three-dimensional using FLAC3D. This model estimates the properties of jointed rock mass from the properties of intact rock and a joint factor (Jf), which is the integration of the properties of joints to take care of the effects of frequency, orientation, and strength of joint. A new FISH function has been written in FLAC3D specifically for modeling jointed rocks using the Duncan and Chang hyperbolic model. This model has been validated first with simple element tests at different confining pressures for different rocks with different joint configurations. Explicit modeling of the joints has also been done in element tests and results obtained compare well with the results of equivalent continuum model and also with experimental results. Further, this has been applied for a case study of a large underground power house cavern in the Himalayas. The analysis has been done under various stages of excavation, assigning a null model available in FLAC3D for simulating the excavation. 相似文献
10.
Higher resolution can be achieved in lithography by decreasing the wavelength of the exposure source. However, resist material
and their processing are also important when we move to a shorter wavelength lithography technology. This paper reviews the
recent development and challenges of deep-UV photoresists and their processing technology. 相似文献