排序方式: 共有51条查询结果,搜索用时 15 毫秒
31.
Abdul-Raouf Al-Mohammadi Ahmed A. Ismaiel Rehab A. Ibrahim Ahmed H. Moustafa Azza Abou Zeid Gamal Enan 《Molecules (Basel, Switzerland)》2021,26(16)
Kombucha is a traditional beverage of sweetened black tea fermented with a symbiotic association of acetic acid bacteria and yeasts. In this study, kombucha fermented beverage (KFB) appeared to include nine chemical groups (alcohols, acids, lactones, condensed heterocyclic compounds, antibiotics, esters, aldehydes, fatty acids, and alkaloids) of many bioactive metabolites, as elucidated by gas chromatography–mass spectrometry (GC-MS) and IR spectra. The fermented metabolic components of KFB seem collectively to act in a synergistic action giving rise to the antimicrobial activity. Four types of kombucha preparations (fermented, neutralized, heat-treated and unfermented) were demonstrated with respect to their antimicrobial activity against some pathogenic bacterial and fungal strains using agar well diffusion assay. KFB exerted the strongest antimicrobial activities when compared with neutralized and heat-treated kombucha beverages (NKB and HKB). Staphylococcus aureus ATCC6538 (S. aureus) and Escherichia coli ATCC11229 (E. coli) were the organisms most susceptible to the antimicrobial activity of kombucha beverage preparations. Finally, the KFB preparation showed remarkable inhibitory activity against S. aureus and E. coli bacteria in a brain heart infusion broth and in some Egyptian fruit juices (apple, guava, strawberry, and tomato). These data reveal that kombucha is not only a prophylactic agent, but also appears to be promising as a safe alternative biopreservative, offering protection against pathogenic bacteria and fungi. 相似文献
32.
Mohamed El-Sherbiny Rehab M. El-Sayed Mohamed A. Helal Afaf T. Ibrahiem Hoda S. Elmahdi Mohamed Ahmed Eladl Shymaa E. Bilay Asma M. Alshahrani Mona K. Tawfik Ziad E. Hamed Amany O. Mohamed Sawsan A. Zaitone 《Molecules (Basel, Switzerland)》2021,26(22)
Nifuroxazide is an antidiarrheal medication that has promising anticancer activity against diverse types of tumors. The present study tested the anticancer activity of nifuroxazide against Ehrlich’s mammary carcinoma grown in vivo. Furthermore, we investigated the effect of nifuroxazide on IL-6/jak2/STAT3 signaling and the possible impact on tumor angiogenesis. The biological study was supported by molecular docking and bioinformatic predictions for the possible effect of nifuroxazide on this signaling pathway. Female albino mice were injected with Ehrlich carcinoma cells to produce Ehrlich’s solid tumors (ESTs). The experimental groups were as follows: EST control, EST + nifuroxazide (5 mg/kg), and EST + nifuroxazide (10 mg/kg). Nifuroxazide was found to reduce tumor masses (730.83 ± 73.19 and 381.42 ± 109.69 mg vs. 1099.5 ± 310.83) and lessen tumor pathologies. Furthermore, nifuroxazide downregulated IL-6, TNF-α, NFk-β, angiostatin, and Jak2 proteins, and it also reduced tumoral VEGF, as indicated by ELISA and immunohistochemical analysis. Furthermore, nifuroxazide dose-dependently downregulated STAT3 phosphorylation (60% and 30% reductions, respectively). Collectively, the current experiment shed light on the antitumor activity of nifuroxazide against mammary solid carcinoma grown in vivo. The antitumor activity was at least partly mediated by inhibition of IL-6/Jak2/STAT3 signaling that affected angiogenesis (low VEGF and high angiostatin) in the EST. Therefore, nifuroxazide might be a promising antitumor medication if appropriate human studies will be conducted. 相似文献
33.
The presence of cationic dyes, even in a tiny amount, is harmful to aquatic life and pollutes the environment. Therefore, it is essential to remove these hazardous dyes to protect the life of marine creatures from these pollutants. In this research, crystal violet (CV) dye elimination was performed using a lignin copper ferrite (LCF) adsorbent. The adsorbent was synthesized and characterized using FTIR, Raman, SEM, EDX with mapping, and VSM, which proved the successful formation of magnetic LCF. Adsorption experiments were performed using different effective parameters. The highest adsorption potential (97%) was executed at mild operating conditions, with a 5 min contact time at room temperature and pH 8. The adsorption kinetic study utilized four kinetic models: first-order, second-order, intraparticle diffusion, and Elovich. The results revealed that the adsorption process complies with the pseudo-first-order with a maximum adsorption capacity of 34.129 mg/g, proving that the adsorption process mechanism is a physical adsorption process. Three isotherm models, Langmuir, Freundlich, and Temkin, were examined. The adsorption mechanism of CV onto LCF was also followed by the Langmuir and Freundlich models. The thermodynamic parameters were examined and revealed that the adsorption onto LCF was an exothermic process. It was proposed that the adsorption process is a spontaneous exothermic process. LCF appears to forcefully remove toxic CV dye from textile wastewater. 相似文献
34.
The Laser Induced Fluorescence (LIF) technique was used to determine a few characteristics of a high Schmidt number (Sc)
passive scalar (fluorescein) in the near-wake of a circular cylinder. The mean and rms concentration indicate that increasing
the Reynolds number (Re) improves the large-scale mixing and accelerates the homogenisation of the scalar. As Re increases,
the intensity of segregation decreases because of turbulent diffusion but the scale of segregation increases due to dispersion.
Comparison between concentration and temperature rms profiles indicates that molecular diffusion has a much smaller effect
on the decay of the scalar variance than the Reynolds number. The ratio of mean-squared values of lateral and streamwise spatial
derivatives of the scalar fluctuation deviates from isotropy, the departure increasing with Re. This reflects more the effect
of dispersion by the turbulent velocity field rather than any molecular diffusion effect. At a given Re, the ratio decreases
as the distance from the cylinder increases. This trend is more accentuated near the edge of the wake than at the centreline.
Received: 16 March 1999/Accepted: 10 June 1999 相似文献
35.
R. Bitane G. Zimbardo P. Pommois P. Veltri 《Communications in Nonlinear Science & Numerical Simulation》2010,15(1):79-85
We report on the numerical computation of the diffusion coefficient D and Kolmogorov entropy h of magnetic field lines extending from the quasilinear up to the percolation regime, using a numerical code where one can change both the turbulence level δB/B0 and the turbulence anisotropy l/l. For the diffusion coefficient, we find that the percolation scaling is reproduced. On the contrary, we find that the proposed percolation scaling of h is not reproduced, but rather a saturation of h is obtained. Also, we find that the Kolmogorov entropy depends only on the Kubo number R=(δB/B0)(l/l), and not separately on δB/B0 and l/l. We apply the results to electron transport in solar coronal loops, which involves the use of the Rechester and Rosenbluth diffusion coefficient, and show that the study of transport in the percolation regime is required. 相似文献
36.
37.
Safaa El-din H. Etaiw Tarek A. Fayed Marwa N. El-Nahass Rehab S. Youssif 《Journal of fluorescence》2015,25(2):283-295
The photophysical behaviors of newly synthesized photochromic dyes have been investigated in different solvents of various polarities using steady-state absorption and emission techniques. It was found that, the absorption and emission spectra of these dyes depend on the ring size and the solvent polarity. The higher values of the dipole moments of the investigated dyes in the excited state than those in the ground state suggest that these dyes can serve as good candidate components of nonlinear optical materials. Additionally, the photoisomerization parameters (percentage of composition of cis isomers and quantum yields of photoisomerization) depend on the polarity and the viscosity of the used solvents as well as the ring size. The molecular motion that occurs in the isomerization process has facilitated the development of molecular devices. Finally, the halochromic behaviors of the investigated dyes promise them to act as acid–base indicators. 相似文献
38.
The chemical oxidation of aniline to form polyaniline (PANI) films was made in the presence of N-phenyl-1,4-phenylenediamine (PPDA) in aqueous hydrochloric acid medium. The PANI films were monitored by using the quartz crystal microbalance (QCM) technique. The effect of PPDA and its concentration on the film formation was investigated. It was found that PPDA decreases the yield of the PANI film, the induction period and the depletion time of the polymerization. However, the growth rate of the film formation was found to increase by increasing PPDA concentration. These results were justified by measuring the UV-VIS absorption spectra for the in situ PANI films and the in situ UV-VIS absorption spectra for the polymer in the bulk during the polymerization. The conductivity for the PANI films at different concentrations of PPDA was measured. Also, the IR spectra, X-ray and the thermal gravimetric analysis for the PANI powder formed in the bulk in the presence of PPDA were measured and discussed. 相似文献
39.
Gemeay AH Mansour IA El-Sharkawy RG Zaki AB 《Journal of colloid and interface science》2003,263(1):228-236
Kinetics of the oxidative degradation of pyrocatechol violet dye (PCV) [2-[(3,4-dihydroxyphenyl)(3-hydroxy-4-oxocyclohexa-2,5-dien-1-ylidene) methyl]-benzenesulfonic acid] by H(2)O(2) catalyzed by supported transition metal complexes have been studied. The reaction was followed by conventional UV-vis spectrophotometer at lambda(max)=440 nm in a buffer solution at pH 5.1. The supports used were silica gel and cation exchange resins (Dowex-50W, 2 and 8% DVB), while the complexes were [Cu(amm)(4)](2+), [Cu(en)(2)](2+), [Cu(ma)(4)](2+), [Co(amm)(6)](2+), and [Ni(amm)(6)](2+) (amm=ammonia, en=ethylenediamine, and ma=methylamine). The reaction exhibited first-order kinetics with respect to [PCV] and [H(2)O(2)]. The reactivity of the catalysts is correlated with the redox potential of the metal ions, the type of support, and the amount of supported complexes. The rate of the reaction increases with increasing pH and the addition of NaCl. Addition of SDS and CTAB showed inhibiting effects. The reaction is enthalpy-controlled as confirmed from the isokinetic relationship. A reaction mechanism involved the generation of free radicals as an oxidant has been proposed. 相似文献
40.
Abdul-Raouf Al-Mohammadi Rehab A. Ibrahim Ahmed H. Moustafa Ahmed A. Ismaiel Azza Abou Zeid Gamal Enan 《Molecules (Basel, Switzerland)》2021,26(9)
Kefir beverage (KB) is a fermented milk initiated by kefir grains rich with starter probiotics. The KB produced in this study seemed to contain many chemical compounds elucidated by gas chromatography–mass spectrometry (GC-MS) and IR spectra. These compounds could be classified into different chemical groups such as alcohols, phenols, esters, fatty esters, unsaturated fatty esters, steroids, polyalkenes, heterocyclic compounds and aromatic aldehydes. Both KB and neutralized kefir beverage (NKB) inhibited some pathogenic bacteria including Escherichia coli ATCC11229 (E. coli), Listeria monocytogenes ATCC 4957 (L. monocytogenes), Bacillus cereus ATCC 14579 (B. cereus), Salmonella typhimurium ATCC 14028 (Sal. typhimurium) as well as some tested fungal strains such as Aspergillus flavus ATCC 16872 (A. flavus) and Aspergillus niger ATCC 20611 (A. niger), but the inhibitory activity of KB was more powerful than that obtained by NKB. It also appeared to contain four lactic acid bacteria species, one acetic acid bacterium and two yeast species. Finally, the KB inhibited distinctively both S. aureus and Sal. typhimurium bacteria in a brain heart infusion broth and in some Egyptian fruit juices, including those made with apples, guava, strawberries and tomatoes. 相似文献