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排序方式： 共有102条查询结果，搜索用时 15 毫秒
71.
Asmaa Sadek Kassab Victor M. Ugaz Maria D. King Yassin A. Hassan 《Aerosol science and technology》2013,47(4):351-360
In an effort to identify particle initial motion prior liftoff interactions of micrometer glass beads (10–100 μm) on glass, ceramic, and hardwood substrates were investigated experimentally. Particles were deposited on the lower surface of a 10 cm2 wind tunnel by gravitational settling. Air flows were imposed from an open entrance at average velocities up to 16 m/s. Individual particle trajectories obtained by high-speed imaging reveal three different types of motion: rolling/bouncing (saltation caused by the movement of hard particles over an uneven surface in a turbulent flow of air), immediate liftoff (particles completely leave the surface with no or minimal initial rolling/bouncing) and complex motion (particles travel with rolling/bouncing motion on the surface for a certain distance before final liftoff). Surface roughness significantly affects the particle initial motion prior to liftoff. The majority of particle trajectories from the glass substrate were parallel to the surface with complex motion. Hardwood substrates took the longest time for initial particle movement (t >1 s) causing a more rapid liftoff. The ceramic substrate showed the most rolling/bouncing motion, for 80% of the particles. The detachment percentage initially follows an exponentially increasing trend for a period of ～1 s, followed by a plateau phase for a period of 5 s. Changing the velocity, substrate, and particle size significantly affects particle detachment. Incorporating the different types of particle motion prior to liftoff into detachment mode models, and understanding how their relative contributions change with different particle and substrate materials, can potentially yield improved predictive capabilities. Copyright 2013 American Association for Aerosol Research 相似文献
72.
Wireless Networks - Intending to enhance the utilization of the radio spectrum in cognitive radio without inflecting the primary user is a primary issue. Cooperative sensing techniques have been... 相似文献
73.
Asmaa H. M. Moneeb Ahmed R. A. Hammam Abdelfatah K. A. Ahmed Mahmoud E. Ahmed Khalid A. Alsaleem 《Food Science & Nutrition》2021,9(6):2936-2942
Milk fat is a complex natural fat and contains around 400 fatty acids. The objectives of this study were to extract fat from bovine milk using two different methods, including Bligh and Dyer and Mojonnier, and to determine the fatty acid content in the extracted fats using gas chromatography (GC). No differences (p > .05) were detected in the fat content and fatty acids content as a percentage of total fat (FA%TF) extracted using both methods. No differences (p > .05) were detected in some saturated fatty acids (SFAs) and unsaturated fatty acids (USFAs) extracted from both methods, such as C11:0 (undecylic acid), C16:0 (palmitic acid), C18:0 (stearic acid), C14:1 (myristoleic acid), and C16:1 (palmitoleic acid). However, the majority of SFAs were different (p < .05) in Mojonnier method as compared to Bligh and Dyer method and vice versa for USFAs. The short (6.54% vs. 5.95%) and medium (21.86% vs. 20.73%) chains FAs determined by GC were high in Mojonnier fat as compared to Bligh and Dyer fat, while the long-chain FAs were higher in the last (66.61%) relative to Mojonnier fat (65.51%). This study found that Mojonneir method has resulted in fewer errors. In contrast, the Bligh and Dyer extraction method has more experimental error, which led to decreasing the total fat, as well as was not able to detect C9:0. 相似文献
74.
Series of polymers based on the grafting of polyacrylamide with both poly(2-methoxyaniline) P2-MeOANI and poly(2-chloroaniline) P2-ClANI were synthesized by the oxidative chemical grafting copolymerization of individually 2-methoxyaniline (2-MeOANI) and 2-chloroaniline (2-ClANI) onto polyacrylamide (PACM). The grafting was performed in aqueous hydrochloric acid solution (HCl) using ammonium persulfate (APS) as oxidant. The optimum conditions of the grafting based on the yield was achieved. The obtained polymer samples at optimum conditions were assembling on colloidal silver nanoparticles (AgNPs). The obtained polymer samples and their AgNPs were characterized by UV- visible & IR spectroscopy, EM, TEM & TGA to confirm the suggested structure of obtained polymers. The efficiency of the prepared polymeric samples to using as anti-microbial including as sulfate reducing bacteria (SRB) was investigated. 相似文献
75.
Torge Hartig Asmaa T. Mohamed Nasra F. Abdel Fattah Aydin Gülses Tim Tjardts Esther Afiba Kangah Kwing Pak Gabriel Chan Salih Veziroglu Yahya Acil Oral Cenk Aktas Jörg Wiltfang Samah A Loutfy Thomas Strunskus Franz Faupel Amal Amin Stefan Schröder 《Advanced Materials Interfaces》2024,11(1):2300587
Thin polymer coatings are used to improve the interface between biological species and functional materials. Their interaction is significantly influenced by the functional groups and roughness of the polymer film and prediction of the interaction is thus of great interest. However, for conventional polymer films, this cannot be examined independently because of the interplay of defects, residual solvent molecules, roughness, and functional groups. Solvent-free polymer films prepared by initiated chemical vapor deposition (iCVD) exhibit conformal, defect-free characteristics and enable precise tailoring of the functional groups. This facilitates to isolate the contribution of functional groups on the bio-interface performance. Consequently, in silico studies can enable a prediction of ligand interaction in anti-viral activity for SARS-CoV-2 based on defined polymer and key protein structures. Furthermore, the cell viability of human fibroblasts can be traced back to the functional groups of the repeating units. For human liver cancer cell culture, it turns out that more sophisticated models are needed. The insilico-iCVD approach can enable precise tailoring of complex polymer films optimized for the respective interfaces. In addition, this first big scan of the bio-interface performance of iCVD films enables a solid starting point in areas like anticancer, antiviral, and biocompatibility for future studies. 相似文献
76.
The model of double‐diffusive convection in a porous medium layer was analyzed using the Brinkman model and concentration based on an internal heat source. Linear instability analysis of the model was performed. Particularly, we analyzed the effect of slip boundary conditions on the instability of the system. We analyzed when the instability started and computed the critical Rayleigh number as a function of the slip coefficient. 相似文献
77.
Asmaa Samir Doaa E. El-Nashar Ahmed H. Ashour Mohamed Medhat Samir U. El-Kameesy 《Polymer Composites》2020,41(2):535-543
The polymer blend polyvinyl chloride/styrene-butadiene rubber filled of (BiO)2CO3 with different concentrations (20, 30, 40, and 60 phr) were prepared by roll mill technique. The gamma-rays attenuation properties were carried out using NaI (Tl) gamma ray spectrometer using 232Th. The attenuation coefficients, half value layer and mean free path were evaluated. The distribution of the filler within the polymer matrix was studied using scanning electron microscopy. The prepared polymer composites were characterized by X-ray diffraction technique to recognize the structural phase of the composites. The hardness and tensile strength of the composites were tested. The tensile strength of the composites was found to be enhanced in the presence of the bismuth subcarbonate filler with a slight decrease when the concentration of the filler exceeds to 40 phr. Attenuation results reveal that, the shielding efficiency increases with the increase of the filler concentration and are comparable to those of the conventional bismuth-polymer shielding materials. Hence, the composites filled (BiO)2CO3 can be used for gamma ray shielding applications. The sample of 40 phr was subjected to gamma irradiation at doses from 30 up to 100 kGy. The dielectric and mechanical properties were investigated as a function of irradiation dose and filler concentrations. It was found that the irradiation dose up to 30 kGy causes an increase in the tensile strength and hardness. There is a remarkable decrease in dielectric constants at irradiation dose from 70 to 100 kGy. The dielectric constants decreased as the concentration of (BiO)2CO3 increased. 相似文献
78.
Asmaa Abdelhamid Amy Jennings Richard P. G. Hayhoe Veronica E. Awuzudike Ailsa A. Welch 《Food Science & Nutrition》2020,8(9):4907-4918
A Mediterranean style dietary pattern (MDP) is considered beneficial for health. The MD Score (MDS) definition has evolved, resulting in considerable variability in the foods and nutrients associated with MDS adherence. We systematically investigated food and nutrient composition of the MD between studies, countries, and methods of classifying the MDS. We searched Embase for MD systematic reviews and selected observational studies reporting intakes of foods, macronutrients, or micronutrients by categories of MDS adherence. The percentage differences in food and nutrient intakes between categories of high and low adherence to the MDS were calculated for each study. A total of 369 full‐text primary papers were reviewed from the included systematic reviews and 74 papers selected (66 adults, 8 children). We found considerable differences in MDS definitions and scoring criteria. Between‐study variation in food intake between high‐ and low‐adherence MDS adherence categories ranged from a mean of −23% for meat, to 119% for fruit, and 278% for fish. Greater variability was evident in non‐Mediterranean than Mediterranean regions. We conclude that few studies report food and nutrient intakes across the range of the MDP in adults and even fewer in children. The considerable variability in the foods and nutrients reported makes comparison of results from studies and translation into dietary guidelines difficult. We recommend that future publications of MD studies include full details of the range of food and nutrient intakes across the distribution of MD adherence in order to facilitate translation into health policy and practice. 相似文献
79.
Asmaa S. Yassein Ahmed H. M. El-Said Eman G. A. El-Dawy 《Flavour and Fragrance Journal》2020,35(2):182-189
Essential oils are natural antimicrobial agents that can be used to control fungal and mycotoxin contamination. Although there are numerous reports discussing the fungal and mycotoxin contamination of foods, there are few researches on baby food contamination so this work aimed to determine the fungal and mycotoxin contamination in cerelac, cornflakes and milk powder and tried to control the mycotoxigenic strain growth and their production of mycotoxins by using essential oils. Cornflakes were heavily contaminated (24 species including 9 genera), while cerelac and milk powder were less contaminated. Aspergillus and Penicillium were the prevalent genera. The produced aflatoxins and ochratoxins from the tested strains of Aspergillus flavus and A. niger were extracted and estimated by fluorometric method. We used the 18S rRNA sequence technique to identify the genotypes of the three isolates. Two isolates were identified as Aspergillus niger and the third isolate as A. flavus. Omt-A gene was detected in the A. flavus, while Aopks gene was detected in A. niger isolates. Amongst the five used essential oils, only cumin and peppermint oil depressed the mycotoxigenic strain growth and peppermint oil had the highest result. Its inhibitory effect on aflatoxin and ochratoxin production was evaluated. Aflatoxin production was highly reduced by 52.1%, but ochratoxin inhibition was very low, 4.88% and 3.17% by A. niger obtained from cornflakes and milk powder, respectively. The three tested samples were contaminated by ochratoxins, but cerelac and milk powder samples were free of aflatoxins. Cornflakes sample recorded the highest reading for both toxins. 相似文献
80.
Adam M. Lee Asmaa Ferdjallah Elise Moore Daniel C. Kim Aritro Nath Emily Greengard R. Stephanie Huang 《International journal of molecular sciences》2021,22(20)
Simple SummaryOsteosarcoma is a bone cancer with a poor prognosis. This is, in part, due to resistance to current standard-of-care chemotherapeutic treatment. As personalized treatment plans become more widely utilized, the role of patient-specific genome markers may serve to identify individuals with chemo-resistant disease at the outset of diagnosis. ANRIL, a long non-coding RNA, has promise as a predictive biomarker. Utilizing osteosarcoma cell lines, we observed that altering the expression of ANRIL significantly alters the sensitivity to cisplatin and doxorubicin, two agents that are a standard-of-care for treatment. Analysis of clinical data from the TARGET dataset confirmed higher ANRIL expression portending poorer prognosis, as evidenced by association with death and metastases at diagnosis.AbstractOsteosarcoma has a poor prognosis due to chemo-resistance and/or metastases. Increasing evidence shows that long non-coding RNAs (lncRNAs) can play an important role in drug sensitivity and cancer metastasis. Using osteosarcoma cell lines, we identified a positive correlation between the expression of a lncRNA and ANRIL, and resistance to two of the three standard-of-care agents for treating osteosarcoma—cisplatin and doxorubicin. To confirm the potential role of ANRIL in chemosensitivity, we independently inhibited and over-expressed ANRIL in osteosarcoma cell lines followed by treatment with either cisplatin or doxorubicin. Knocking-down ANRIL in SAOS2 resulted in a significant increase in cellular sensitivity to both cisplatin and doxorubicin, while the over-expression of ANRIL in both HOS and U2OS cells led to an increased resistance to both agents. To investigate the clinical significance of ANRIL in osteosarcoma, we assessed ANRIL expression in relation to clinical phenotypes using the osteosarcoma data from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) dataset. Higher ANRIL expression was significantly associated with increased rates of metastases at diagnosis and death and was a significant predictor of reduced overall survival rate. Collectively, our results suggest that the lncRNA ANRIL can be a chemosensitivity and prognosis biomarker in osteosarcoma. Furthermore, reducing ANRIL expression may be a therapeutic strategy to overcome current standard-of-care treatment resistance. 相似文献