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991.
The transport of carbamazepine, ciprofloxacin and sulfamethoxazole in the different pores of activated carbon in an aqueous solution is a dynamic process that is entirely dependent on the intrinsic parameters of these molecules and of the adsorbent. The macroscopic processes that take place are analyzed by interfacial diffusion and reaction models. Modeling of the experimental kinetic curves obtained following batch treatment of each solute at 2 µg/L in tap water showed (i) that the transport and sorption rates were controlled by external diffusion and intraparticle diffusion and (ii) that the effective diffusion coefficient for each solute, with the surface and pore diffusion coefficients, were linked by a linear relationship. A statistical analysis of the experimental data established correlations between the diffusional parameters and some geometrical parameters of these three molecules. Given the major discontinuities observed in the adsorption kinetics, the modeling of the experimental data required the use of traditional kinetic models, as well as a new kinetic model composed of the pseudo first or second order model and a sigmoidal expression. The predictions of this model were excellent. The solubility of each molecule below 60 °C was formulated by an empirical expression. 相似文献
992.
Aftab Shaukat Irfan Shaukat Shahid Ali Rajput Rizwan Shukat Sana Hanif Imran Shaukat Xinxin Zhang Chao Chen Xuyang Sun Tingzhu Ye Kaifeng Niu Zhiqiu Yao Shadab Shaukat Muhammad Safdar Mohamed Abdelrahman Umair Riaz Junwei Zhao Xiaoying Gu Liguo Yang 《Molecules (Basel, Switzerland)》2021,26(23)
Endometritis is the inflammatory response of the endometrial lining of the uterus and is associated with low conception rates, early embryonic mortality, and prolonged inter-calving intervals, and thus poses huge economic losses to the dairy industry worldwide. Ginsenoside Rb1 (GnRb1) is a natural compound obtained from the roots of Panax ginseng, having several pharmacological and biological properties. However, the anti-inflammatory properties of GnRb1 in lipopolysaccharide (LPS)-challenged endometritis through the TLR4-mediated NF-κB signaling pathway has not yet been researched. This study was planned to evaluate the mechanisms of how GnRb1 rescues LPS-induced endometritis. In the present research, histopathological findings revealed that GnRb1 ameliorated LPS-triggered uterine injury. The ELISA and RT-qPCR assay findings indicated that GnRb1 suppressed the expression level of pro-inflammatory molecules (TNF-α, IL-1β and IL-6) and boosted the level of anti-inflammatory (IL-10) cytokine. Furthermore, the molecular study suggested that GnRb1 attenuated TLR4-mediated NF-κB signaling. The results demonstrated the therapeutic efficacy of GnRb1 in the mouse model of LPS-triggered endometritis via the inhibition of the TLR4-associated NF-κB pathway. Taken together, this study provides a baseline for the protective effect of GnRb1 to treat endometritis in both humans and animals. 相似文献
993.
Nouria A. Al-Awadi Mohamed H. Elnagdi Tommy Mathew Ibrahim El-Gamry Mervat Abdel Khalik 《国际化学动力学杂志》1996,28(10):741-748
Pyrolysis of the Schiff bases of 1-arylmethyleneamino-1,2-dihydro-4,6-dimethyl-2-oxopyridine-3-carbonitriles (1–5) has been studied. These compounds eliminate via a six-membered transition state to produce substituted benzonitriles and 2-hydroxy-4,6-dimethylpyridine-3-carbonitrile. These eliminations are unimolecular first-order reactions. The kinetic data gave a good correlation with σ0 values of the substituents on the aryl group with ρ = 0.83 at 520 K. Utilization of the pyrolytic reaction in synthesis of various benzonitriles is considered, and mechanistic information has been obtained by comparing the kinetic data and product analysis of the Schiff bases with their open-chain substituted benzaldehyde cyanoacetylhydrazones (6–9) analogues. © 1996 John Wiley & Sons, Inc. 相似文献
994.
Anhar Abdel-Aziem Huda Refaat Mahmoud Rashdan Entesar Mohamed Ahmed Sara N. Shabaan 《Green Chemistry Letters and Reviews》2019,12(1):9-18
In the present study, a rapid, less expensive, clean and environmental friendly route to synthesis new pyrazoles, pyrazolopyridazines and condensed pyrimidines was developed via grinding of 2-(3-(dimethylamino)acryloyl)-3H-benzo[f]chromen-3-one (1) with different reagents. All the new compounds were characterized and established using elemental analysis and spectral data. Eight compounds were selected for in vitro antiproliferative against different human cancer cell lines entitled melanoma, cancers of the lung, leukemia, breast, brain, colon, prostate, ovary and kidney by the USA NCI. 相似文献
995.
Abdillah Sani Bin Mohd Najib Xiaobo Peng Ayako Hashimoto Shusaku Shoji Takayuki Iida Yunxing Bai Hideki Abe 《化学:亚洲杂志》2019,14(16):2802-2805
Mesoporous precious metals with abundant active sites and high surface area have been widely recognized as high‐performance catalytic materials. However, the templated synthesis is complex and costly. Herein, we report a mesoporous rhodium (m‐Rh) that can be readily synthesized from entangled nanofibres of Rh and Y2O3 without templates. The entangled nanofibres, prepared from uniform Rh‐Y alloys under redox atmosphere, were the key precursor in the synthesis processes. Moreover, the m‐Rh efficiently catalyzed carbon dioxide reforming of methane (DRM) at a low reaction temperature of 683 K. Further, electrochemical methods of CO electro‐oxidation were innovatively used to demonstrate the stability of CO and oxygen species for the DRM reaction. 相似文献
996.
Hanene Zemmouri Sonda Ammar Amel Boumendjel Mahfoud Messarah Abdelfattah El Feki Mohamed Bouaziz 《Arabian Journal of Chemistry》2019,12(8):1954-1963
The aqueous and hydroalcoholic extracts of borage (Borago officinalis) leaves from Annaba region (Algeria) were preliminary analyzed for their phenolic profile (total phenolics, total flavonoids, total flavonols, total tannins and total anthocyanins). These extracts were evaluated for their antioxidant properties by different methods such as DPPH radical scavenging, test NBT and total antioxidant activity. The two extracts have exhibited a high antiradical capacity. Indeed, the ethanolic extract showed the lower IC50 values and the highest amount of phenolics (94.09 ± 1.72 mg gallic acid/g dry extract). Using LC-MS/MS analysis, it was possible to identify phenolic acids, flavonoids, sterol and for the first time oleuropein was identified in the aqueous extract of the plant. The obtained results have demonstrated that phenolic compounds are the major contributor to the antioxidant activity of plants. 相似文献
997.
Optical Review - The analytical solution of a three-level atom interacting with four systems of N-two-level atoms is studied. The atomic inversion and the correlation function as applications of... 相似文献
998.
Derek Ingham Maurizio Troiano Mohamed Pourkashanian 《Proceedings of the Combustion Institute》2019,37(3):2995-3003
The tendency of ash particles to stick under high temperatures is dictated by the ash chemistry, particle physical properties, deposit surface properties and furnace operation conditions. A model has been developed in order to predict the particle sticking efficiency for fly ash deposition at high temperatures. The model incorporates the particle properties relevant to the ash chemistry, particle kinetic energy and furnace operation conditions and takes into consideration the partial sticking behaviour and the deposit layer. To test the model, the sticking behaviours of synthetic ash in a drop tube furnace are evaluated and the slagging formation from coal combustion in a down-fired furnace is modelled. Compared with the measurements, the proposed model presents reasonable prediction performance on the particle sticking behaviour and the ash deposition formation. Through a sensitivity analysis, furnace operation conditions (velocity and temperature), contact angle and particle size have been found to be the significant factors in controlling the sticking behaviours for the synthetic ash particles. The ash chemistry and furnace temperature dictate the wetting potential of the ash particles and the melting ability of the deposit surface; particle size and density not only control the particle kinetic energy, but also affect the particle temperature. The furnace velocity condition has been identified as being able to influence the selective deposition behaviour, where the maximum deposition efficiency moves to smaller particles when increasing the gas velocity. In addition, the thermophoresis effect on the arrival rate of the particles reduces with increasing the gas velocity. Further, increasing the melting degree of the deposit layer could greatly enhance the predicted deposition formation, in particular for the high furnace velocity condition. 相似文献
999.
Mohamed E. Mostafa 《Proceedings of the Combustion Institute》2019,37(3):3053-3060
Fluorescence interference in Raman spectrum is a big barrier for rapid and precise analysis of coal structures by Raman spectroscopy. Dealing with fluorescence interference suitably is one of the key tasks before efficient application of Raman spectroscopy in coal assessment. In this study, Raman spectra and coal combustion characteristics of 32 kinds of Chinese coals were respectively obtained in a micro-Raman spectrometer and Thermal Gravimetric Analyzer. The degree of fluorescence interference in Raman spectrum was firstly defined and quantified as the drift coefficient α using a simple method without curve-fitting the spectrum. The correlations between the degree of fluorescence interference and coal property, coal combustion characteristics were set up and multivariable analysis was done. The results indicate that the degree of fluorescence interference is well related to the coal structures, and it is synthetically determined by volatile, moisture and ash content in coal. With the increase of volatile, moisture content in coal, the fluorescence interference increases continuously, and it can be reduced but not eliminated by drying the moisture in coals. Significant mathematical relations between the drift coefficient α and volatile, moisture content, coal combustion characteristic temperatures have been found. Coal with more evident fluorescence interference in Raman spectrum usually has lower degree of coalification, more polar functional groups, and burns at a lower temperature. The drift coefficient α can act as an efficient probe for coal property and coal combustion characteristics. This study provided a new and simple approach for evaluating coal property and coal combustion characteristics by fluorescence interference in Raman spectrum. 相似文献
1000.
Stability analysis of internally damped rotating composite shafts using a finite element formulation
Safa Ben Arab José Dias Rodrigues Slim Bouaziz Mohamed Haddar 《Comptes Rendus Mecanique》2018,346(4):291-307
This paper deals with the stability analysis of internally damped rotating composite shafts. An Euler–Bernoulli shaft finite element formulation based on Equivalent Single Layer Theory (ESLT), including the hysteretic internal damping of composite material and transverse shear effects, is introduced and then used to evaluate the influence of various parameters: stacking sequences, fiber orientations and bearing properties on natural frequencies, critical speeds, and instability thresholds. The obtained results are compared with those available in the literature using different theories. The agreement in the obtained results show that the developed Euler–Bernoulli finite element based on ESLT including hysteretic internal damping and shear transverse effects can be effectively used for the stability analysis of internally damped rotating composite shafts. Furthermore, the results revealed that rotor stability is sensitive to the laminate parameters and to the properties of the bearings. 相似文献