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排序方式: 共有94条查询结果,搜索用时 10 毫秒
41.
Victor Markus Orr Share Kerem Teral Nazmi Ozer Robert S. Marks Ariel Kushmaro Karina Golberg 《Molecules (Basel, Switzerland)》2020,25(22)
Governments are creating regulations for consumers to reduce their sugar intake, prompting companies to increase the ratio of artificial sweeteners in their products. However, there is evidence of some deleterious effects ascribed to the aforementioned synthetic agents and therefore consumers and food manufacturers have turned their attention to natural dietary sweeteners, such as stevia, to meet their sweetening needs. Stevia is generally considered safe; however, emerging scientific evidence has implicated the agent in gut microbial imbalance. In general, regulation of microbial behavior is known to depend highly on signaling molecules via quorum sensing (QS) pathways. This is also true for the gut microbial community. We, therefore, evaluated the possible role of these stevia-based natural sweeteners on this bacterial communication pathway. The use of a commercial stevia herbal supplement resulted in an inhibitory effect on bacterial communication, with no observable bactericidal effect. Purified stevia extracts, including stevioside, rebaudioside A (Reb A), and steviol revealed a molecular interaction, and possible interruption of Gram-negative bacterial communication, via either the LasR or RhlR receptor. Our in-silico analyses suggest a competitive-type inhibitory role for steviol, while Reb A and stevioside are likely to inhibit LasR-mediated QS in a non-competitive manner. These results suggest the need for further safety studies on the agents. 相似文献
42.
Modeling and control of vehicle suspension system are high noteworthy from safety to comfort. In this paper, an analytical
nonlinear half-vehicle model which is included quadratic tire stiffness, cubic suspension stiffness, and coulomb friction
is derived based on fundamental physics. A hybrid fuzzy logic approach which combines fuzzy logic and PID controllers is designed
for reducing the vibration levels of passenger seat and vehicle body. Performances of designed controllers have been evaluated
by numerical simulations. Comparisons with classical PID control, Fuzzy Logic Control (FLC) and Hybrid Fuzzy-PID control (HFPID)
have also been provided. Results of numerical simulations are evaluated in terms of time histories of displacement and acceleration
responses and ride index comparison. A good performance for the Hybrid Fuzzy-PID controller with coupled rules (HFPIDCR) is
achieved in simulation studies despite the nonlinearities. 相似文献
43.
Ahmet Ozer Sehirli Serkan Sayner Ugochukwu Chukwunyere Nedime Serakinci 《Molecules (Basel, Switzerland)》2021,26(15)
The cellular utilization of oxygen leads to the generation of free radicals in organisms. The accumulation of these free radicals contributes significantly to aging and several age-related diseases. Angiotensin II can contribute to DNA damage through oxidative stress by activating the NAD(P)H oxidase pathway, which in turn results in the production of reactive oxygen species. This radical oxygen-containing molecule has been linked to aging and several age-related disorders, including renal damage. Considering the role of angiotensin in aging, melatonin might relieve angiotensin-II-induced stress by enhancing the mitochondrial calcium uptake 1 pathway, which is crucial in preventing the mitochondrial calcium overload that may trigger increased production of reactive oxygen species and oxidative stress. This review highlights the role and importance of melatonin together with angiotensin in aging and age-related diseases. 相似文献
44.
Giacomo Saban 《Annali di Matematica Pura ed Applicata》1962,60(1):111-133
Sunto Associate, in maniera metricamente intrinseca, ad una curva sghemba (X) in En due superficie rigate ℛ eC, di cui l'una sviluppabile e l'altra un cono, passanti ambedue per (X) ed aventi un raccordo in corrispondenza ad un punto
X0 generico su questa curva, vengono esaminati gli ordini di contatto delle due curve (r) e (c) segate su queste due superficie
da un iperpiano π. L'ordine del contatto stesso risulta indipendente sia dalla scelta di (X) che da quella di X0.
A Enrico Bompiani in occasione del suo Giubileo scientifico. 相似文献
45.
Cemile Ozcan Ulviye Kanburoglu Cebi Mehmet Ali Gurbuz Selcuk Ozer 《Chromatographia》2017,80(6):941-950
Sunflower agriculture is an important subsector that plays a key role in the economy of Turkey, contributing 1.38 million tonnes. The aim of this study is to investigate the levels of imidazolinone (IMI) group herbicides in Thrace Region, Turkey. In particular, we aimed to determine the residue levels of imazamox, a herbicide used in sunflower production in Thrace Region, in soil, different parts of plant, and seed. Five herbicides were identified in sunflower samples using solid–liquid extraction with gas chromatography–electrospray ionization mass spectrometry (GC–EI–MS) on single-quadruple instruments in selected ion monitoring (SIM) mode. The optimized conditions were found to be mobile-phase flow rate of 1 mL min?1 and injection volume of 3 μL in programmed temperature vaporization (PTV) solvent vent mode. The recovery of imazamox, imazaquin, imazethapyr, imazapyr, and imazapic from sunflower plant and soil was 89 and 99, 104 and 105, 92 and 93, 96 and 92, and 99 and 96%, respectively. 相似文献
46.
Jessica Hao Ivana Stavljeni Milain Zeynep Batu Eken Marinka Mravak-Stipetic Kreimir Paveli Fusun Ozer 《Molecules (Basel, Switzerland)》2021,26(20)
Zeolites and zeolitic imidazolate frameworks (ZIFs) are widely studied as drug carrying nanoplatforms to enhance the specificity and efficacy of traditional anticancer drugs. At present, there is no other systematic review that assesses the potency of zeolites/ZIFs as anticancer drug carriers. Due to the porous nature and inherent pH-sensitive properties of zeolites/ZIFs, the compounds can entrap and selectively release anticancer drugs into the acidic tumor microenvironment. Therefore, it is valuable to provide a comprehensive overview of available evidence on the topic to identify the benefits of the compound as well as potential gaps in knowledge. The purpose of this study was to evaluate the potential therapeutic applications of zeolites/ZIFs as drug delivery systems delivering doxorubicin (DOX), 5-fluorouracil (5-FU), curcumin, cisplatin, and miR-34a. Following PRISMA guidelines, an exhaustive search of PubMed, Scopus, Embase, and Web of Science was conducted. No language or time limitations were used up to 25th August 2021. Only full text articles were selected that pertained to the usage of zeolites/ZIFs in delivering anticancer drugs. Initially, 1279 studies were identified, of which 572 duplicate records were excluded. After screening for the title, abstract, and full texts, 53 articles remained and were included in the qualitative synthesis. An Inter-Rater Reliability (IRR) test, which included a percent user agreement and reliability percent, was conducted for the 53 articles. The included studies suggest that anticancer drug-incorporated zeolites/ZIFs can be used as alternative treatment options to enhance the efficacy of cancer treatment by mitigating the drawbacks of drugs under conventional treatment. 相似文献
47.
基于CTAB对双金属银铜氧化物Ag2Cu2Ox的刻蚀及硫代硫酸钠溶解副产物AgBr的方法制备了两种多孔纳米CuO骨架结构,并且利用X射线衍射仪,X射线光电子能谱仪和洛伦兹透射电镜进一步研究了刻蚀机理,结果表明CuO有独特的形貌结构和更大的比表面积。利用所制备的氧化铜具有大孔隙和多位点的优势,开展了H2S气体传感实验。实验结果显示,在150℃的较低温度下纳米CuO传感器对 500 ppb H2S仍具有1.7(CuO-Ag2Cu2O3)和1.3(CuO-Ag2Cu2O4)的灵敏度值,响应和恢复时间短,具有良好的选择性和长期稳定性,未来还可以通过构建异质结或者贵金属修饰多孔氧化铜来进一步提高传感性能。 相似文献
48.
Christopher Lai Ashten Nguyen Lynna Ye Jessica Hao Hyun Koo Francis Mante Fusun Ozer 《Molecules (Basel, Switzerland)》2022,27(24)
Polymethyl methacrylate (PMMA), an acrylic resin used in orthodontic appliances and removable dentures for its biocompatibility and esthetics, may harbor bacteria on its surface. The present study investigated a new PMMA formula with Gantrez: an antibacterial copolymer of methyl vinyl ether and maleic acid (PVM/MA). Samples were tested for mechanical properties (surface hardness, flexural strength, water sorption, and water solubility) and effects against Streptococcus mutans. Six groups (0%-control, 5%, 10%, 15%, 20%, and 25% Gantrez) of n = 12 were fabricated for physical property tests and analyzed with one-way ANOVA and Prism 6. From these results, three groups (0%, 5%, and 10% Gantrez) were selected for antibacterial tests, and data were analyzed with one-way ANOVA and Tukey’s multiple comparison test. Adding 5% and 10% Gantrez into PMMA significantly decreased S. mutans adhesion. There was no significant difference between the control vs. 5%, 10%, 15%, and 20% Gantrez (p > 0.05) for surface hardness, the control vs. 5% Gantrez (p > 0.05) for flexural strength, and the control vs. 5 and 10% Gantrez for water sorption and water solubility. Overall, incorporating 5% Gantrez into PMMA may be a promising solution to reduce bacterial adhesion without changing the acrylic resin’s physical properties. 相似文献
49.
Proton conducting tantalum oxide films were deposited on ITO (Indium Tin Oxide) coated glass, fused silica and soda-lime glass
substrates by spin coating using a sol-gel process. The coating solutions were prepared using Ta(OC2H5)5 as a precursor. X-ray diffraction studies determined that the sol-gel films, heat treated at temperatures below 400°C, were
amorphous. Films heat treated at higher temperatures were crystalline with the hexagonal δ-Ta2O5 structure. The solar transmission values (T
s
) of tantala films on glass generally range from 0.8–0.9, depending on thickness. The refractive index and the extinction
coefficient were evaluated from transmittance characteristics in the UV-VIS-NIR regions. The refractive index values calculated
at λ=550 nm increased fromn=1.78 to 1.97 with increasing heat treatment from 150 to 450°C. The films heat treated at different temperatures showed low
absorption, with extinction coefficients of smaller thank=1×10−3 in the visible range. Impedance spectroscopic investigations performed on Ta2O5 films revealed that these films have a protonic conductivity of 3.2×10−4S/m. The films are suitable for proton conducting layers in electrochromic (EC) devices. 相似文献
50.
Victor Markus Karina Golberg Kerem Teral Nazmi Ozer Esti Kramarsky-Winter Robert S. Marks Ariel Kushmaro 《Molecules (Basel, Switzerland)》2021,26(6)
Quorum sensing (QS), a sophisticated system of bacterial communication that depends on population density, is employed by many pathogenic bacteria to regulate virulence. In view of the current reality of antibiotic resistance, it is expected that interfering with QS can address bacterial pathogenicity without stimulating the incidence of resistance. Thus, harnessing QS inhibitors has been considered a promising approach to overriding bacterial infections and combating antibiotic resistance that has become a major threat to public healthcare around the globe. Pseudomonas aeruginosa is one of the most frequent multidrug-resistant bacteria that utilize QS to control virulence. Many natural compounds, including furanones, have demonstrated strong inhibitory effects on several pathogens via blocking or attenuating QS. While the natural furanones show no activity against P. aeruginosa, furanone C-30, a brominated derivative of natural furanone compounds, has been reported to be a potent inhibitor of the QS system of the notorious opportunistic pathogen. In the present study, we assess the molecular targets and mode of action of furanone C-30 on P. aeruginosa QS system. Our results suggest that furanone C-30 binds to LasR at the ligand-binding site but fails to establish interactions with the residues crucial for the protein’s productive conformational changes and folding, thus rendering the protein dysfunctional. We also show that furanone C-30 inhibits RhlR, independent of LasR, suggesting a complex mechanism for the agent beyond what is known to date. 相似文献