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排序方式: 共有1146条查询结果,搜索用时 125 毫秒
1.
Reem S. Alnefaie Mohamed Abboud Abdullah Alhanash Mohamed S. Hamdy 《Molecules (Basel, Switzerland)》2022,27(10)
Nickel oxide powder was prepared by simple calcination of nickel nitrate hexahydrate at 500 °C for 5 h and used as a catalyst for the oxidation of cyclohexane to produce the cyclohexanone and cyclohexanol—KA oil. Molecular oxygen (O2), hydrogen peroxide (H2O2), t-butyl hydrogen peroxide (TBHP) and meta-chloroperoxybenzoic acid (m-CPBA) were evaluated as oxidizing agents under different conditions. m-CPBA exhibited higher catalytic activity compared to other oxidants. Using 1.5 equivalent of m-CPBA as an oxygen donor agent for 24 h at 70 °C, in acetonitrile as a solvent, NiO powder showed exceptional catalytic activity for the oxidation of cyclohexane to produce KA oil. Compared to different catalytic systems reported in the literature, for the first time, about 85% of cyclohexane was converted to products, with 99% KA oil selectivity, including around 87% and 13% selectivity toward cyclohexanone and cyclohexanol, respectively. The reusability of NiO catalyst was also investigated. During four successive cycles, the conversion of cyclohexane and the selectivity toward cyclohexanone were decreased progressively to 63% and 60%, respectively, while the selectivity toward cyclohexanol was increased gradually to 40%. 相似文献
2.
Katren F. Khella Ahmed I. Abd El Maksoud Amr Hassan Shaimaa E. Abdel-Ghany Rafaat M. Elsanhoty Mohammed Abdullah Aladhadh Mohamed A. Abdel-Hakeem 《Molecules (Basel, Switzerland)》2022,27(13)
Carnosic acid (CA) is a natural phenolic compound with several biomedical actions. This work was performed to study the use of CA-loaded polymeric nanoparticles to improve the antitumor activity of breast cancer cells (MCF-7) and colon cancer cells (Caco-2). CA was encapsulated in bovine serum albumin (BSA), chitosan (CH), and cellulose (CL) nanoparticles. The CA-loaded BSA nanoparticles (CA-BSA-NPs) revealed the most promising formula as it showed good loading capacity and the best release rate profile as the drug reached 80% after 10 h. The physicochemical characterization of the CA-BSA-NPs and empty carrier (BSA-NPs) was performed by the particle size distribution analysis, transmission electron microscopy (TEM), and zeta potential. The antitumor activity of the CA-BSA-NPs was evaluated by measuring cell viability, apoptosis rate, and gene expression of GCLC, COX-2, and BCL-2 in MCF-7 and Caco-2. The cytotoxicity assay (MTT) showed elevated antitumor activity of CA-BSA-NPs against MCF-7 and Caco-2 compared to free CA and BSA-NPs. Moreover, apoptosis test data showed an arrest of the Caco-2 cells at G2/M (10.84%) and the MCF-7 cells at G2/M (4.73%) in the CA-BSA-NPs treatment. RT-PCR-based gene expression analysis showed an upregulation of the GCLC gene and downregulation of the BCL-2 and COX-2 genes in cells treated with CA-BSA-NPs compared to untreated cells. In conclusion, CA-BSA-NPs has been introduced as a promising formula for treating breast and colorectal cancer. 相似文献
3.
Joelle Mesmar Rola Abdallah Adnan Badran Marc Maresca Abdullah Shaito Elias Baydoun 《Molecules (Basel, Switzerland)》2022,27(13)
Ziziphus nummularia, a small bush of the Rhamnaceae family, has been widely used in traditional folk medicine, is rich in bioactive molecules, and has many reported pharmacological and therapeutic properties. Objective: To gather the current knowledge related to the medicinal characteristics of Z. nummularia. Specifically, its phytochemical contents and pharmacological activities in the treatment of various diseases such as cancer, diabetes, and cardiovascular diseases, are discussed. Methods: Major scientific literature databases, including PubMed, Scopus, ScienceDirect, SciFinder, Chemical Abstracts, Medicinal and Aromatic Plants Abstracts, Henriette’s Herbal Homepage, Dr. Duke’s Phytochemical and Ethnobotanical Databases, were searched to retrieve articles related to the review subject. General web searches using Google and Google scholar were also utilized. The search period covered articles published between 1980 and the end of October 2021.The search used the keywords ‘Ziziphus nummularia’, AND (‘phytochemical content’, ‘pharmacological properties, or activities, or effects, or roles’, ‘anti-inflammatory’, ‘anti-drought’, ‘anti-thermal’, ‘anthelmintic’, ‘antidiabetic’,’ anticancer’, ‘anticholinesterase’, ‘antimicrobial’, ‘sedative’, ‘antipyretic’, ‘analgesic’, or ‘gastrointestinal’). Results: This plant is rich in characteristic alkaloids, especially cyclopeptide alkaloids such as nummularine-M. Other phytochemicals, including flavonoids, saponins, glycosides, tannins, and phenolic compounds, are also present. These phytochemicals are responsible for the reported pharmacological properties of Z. nummularia, including anti-inflammatory, antioxidant, antimicrobial, anthelmintic, antidiabetic, anticancer, analgesic, and gastrointestinal activities. In addition, Z. nummularia has anti-drought and anti-thermal characteristics. Conclusion: Research into the phytochemical and pharmacological properties of Z. nummularia has demonstrated that this plant is a rich source of novel bioactive compounds. So far, Z. nummularia has shown a varied pharmacological profile (antioxidant, anticancer, anti-inflammatory, and cardioprotective), warranting further research to uncover the therapeutic potential of the bioactives of this plant. Taken together, Z. nummularia may represent a new potential target for the discovery of new drug leads. 相似文献
4.
Ashraf M. Muhammad Ali Zari Nouf H. Alsubhi Maryam H. Al-Zahrani Rana Abdullah Alghamdi Mai M. Labib 《Molecules (Basel, Switzerland)》2022,27(14)
Aptamers, the nucleic acid analogs of antibodies, bind to their target molecules with remarkable specificity and sensitivity, making them promising diagnostic and therapeutic tools. The systematic evolution of ligands by exponential enrichment (SELEX) is time-consuming and expensive. However, regardless of those issues, it is the most used in vitro method for selecting aptamers. Therefore, recent studies have used computational approaches to reduce the time and cost associated with the synthesis and selection of aptamers. In an effort to present the potential of computational techniques in aptamer selection, a simple sequence-based method was used to design a 69-nucleotide long aptamer (mod_09) with a relatively stable structure (with a minimum free energy of −32.2 kcal/mol) and investigate its binding properties to the tyrosine kinase domain of the NT-3 growth factor receptor, for the first time, by employing computational modeling and docking tools. 相似文献
5.
Abdullah Algin 《Czechoslovak Journal of Physics》2002,52(9):1011-1019
A two-parameter deformed N = 2 SUSY algebra is constructed by using the q-deformed bosonic and fermionic Newton oscillator algebras. The Fock space representation of the (q
1,q
2)-deformed N = 2 SUSY algebra is analyzed. The comparison between the algebra constructed and earlier versions of deformed N = 2 SUSY algebras is also made. 相似文献
6.
Ishani Chatterjee Mengchu Zhou Abdullah Abusorrah Khaled Sedraoui Ahmed Alabdulwahab 《Entropy (Basel, Switzerland)》2021,23(12)
People nowadays use the internet to project their assessments, impressions, ideas, and observations about various subjects or products on numerous social networking sites. These sites serve as a great source to gather data for data analytics, sentiment analysis, natural language processing, etc. Conventionally, the true sentiment of a customer review matches its corresponding star rating. There are exceptions when the star rating of a review is opposite to its true nature. These are labeled as the outliers in a dataset in this work. The state-of-the-art methods for anomaly detection involve manual searching, predefined rules, or traditional machine learning techniques to detect such instances. This paper conducts a sentiment analysis and outlier detection case study for Amazon customer reviews, and it proposes a statistics-based outlier detection and correction method (SODCM), which helps identify such reviews and rectify their star ratings to enhance the performance of a sentiment analysis algorithm without any data loss. This paper focuses on performing SODCM in datasets containing customer reviews of various products, which are (a) scraped from Amazon.com and (b) publicly available. The paper also studies the dataset and concludes the effect of SODCM on the performance of a sentiment analysis algorithm. The results exhibit that SODCM achieves higher accuracy and recall percentage than other state-of-the-art anomaly detection algorithms. 相似文献
7.
The effects of quantum confined stark effect (QCSE) and quantum well (QW) thickness on the optical properties of violet InGaN laser diodes (LDs) have numerically been investigated. The simulation results indicated that the QCSE greatly effects the optical properties of LDs, where QCSE relates to the QW thickness and it increases when the QW thickness is wider which leads to deteriorating of the optical proprieties of the violet InGaN LD. The polarization in the active region of the InGaN LD has been estimated by the blue shift of the wavelength and it is found that the blue shift of the wavelength depends on the QW thickness. The major simulation result has shown that the best properties of violet InGaN LD can be obtained with smaller QW thickness, where more carriers can be restricted, stayed and overlapped inside the QW which leads to a larger stimulated recombination rate and optical material gain which in turn increase the output power of the LD; while decreasing the threshold current of the LD. 相似文献
8.
The present paper deal with the multi-component condensation of 8-hydroxy quinoline, aromatic aldehydes, and sulfone derivatives catalyzed by p-toluenesulfonic acid for the synthesis of a series of 4H-pyrano[3,2-h]quinoline derivatives in ethanol under ultrasonic irradiations. We provide a series of quinoline derivatives containing sulfone moiety interesting for biological screening tests. The reactions were carried out under both conventional and ultrasonic irradiation conditions. In general, improvement in rates and yields were observed when reactions were carried out under sonication compared with classical silent conditions. Also, also, sonochemical reaction give different reaction pathway other than silent reaction. These remarkable effects appeared in sonicated reactions can be reasonably interpreted in terms of acoustic cavitation phenomenon. Structures of the products were established on analytical and spectral data. 相似文献
9.
We have carried out some photon interaction measurements using 59.54 keV γ-rays from a 241Am source. These include γ attenuation studies as well as photoelectric absorption studies in various samples. The attenuation
studies have been made using leaf and wood samples, samples like sand, sugar etc., which contain particles of varying sizes
as well as pellets and aqueous solutions of rare earth compounds. In the case of the leaf and wood samples, we have used the
γ-ray attenuation technique for the determination of the water content in fresh and dried samples. The variation of the attenuation
coefficient with particle size has been investigated for sand and sugar samples. The attenuation studies as well as the photoelectric
studies in the case of rare earth elements have been carried out on samples containing such elements whose K-absorption edge
energies lie below and close to the γ-energy used. Suitable compounds of the rare earth elements have been chosen as mixture
absorbers in these investigations. A narrow beam good geometry set-up was used for the attenuation measurements. A well-shielded
scattering geometry was used for the photoelectric measurements. The mixture rule was invoked to extract the values of the
mass attenuation coefficients for the elements from those of the corresponding compounds. The results are consistent with
theoretical values derived from the XCOM package. 相似文献
10.
M. N. Subramaniam P. S. Goh N. Abdullah W. J. Lau B. C. Ng A. F. Ismail 《Journal of nanoparticle research》2017,19(6):220
Removal of methylene blue (MB) via adsorption and photocatalysis using titanate nanotubes (TNTs) with different surface areas were investigated and compared to commercial titanium dioxide (TiO2) P25 Degussa nanoparticles. The TNTs with surface area ranging from 20 m2/g to 200 m2/g were synthesized via hydrothermal method with different reaction times. TEM imaging confirmed the tubular structure of TNT while XRD spectra indicated all TNTs exhibited anatase crystallinity. Batch adsorption rate showed linearity with surface properties of TNTs, where materials with higher surface area showed higher adsorption rate. The highest MB adsorption (70%) was achieved by TNT24 in 60 min whereas commercial TiO2 exhibited the lowest adsorption of only 10% after 240 min. Adsorption isotherm studies indicated that adsorption using TNT is better fitted into Langmuir adsorption isotherm than Freundlich isotherm model. Furthermore, TNT24 was able to perform up to 90% removal of MB within 120 min, demonstrating performance that is 2-fold better compared to commercial TiO2. The high surface area and surface Bronsted acidity are the main reasons for the improvement in MB removal performance exhibited by TNT24. The improvement in surface acidity enhanced the adsorption properties of all the nanotubes prepared in this study. 相似文献