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排序方式: 共有191条查询结果,搜索用时 15 毫秒
61.
Knowledge and Information Systems - Learning to rank (LTR) is the process of constructing a model for ranking documents or objects. It is useful for many applications such as Information retrieval... 相似文献
62.
A.I. Zaky Farahat T. El-Bitar Eman El-Shenawy 《Materials Science and Engineering: A》2008,492(1-2):161-167
Austenitic stainless steel has excellent ductility. Consequently, it has capability for heavily cold deformation, despite its high strength and high work hardening ability. Austenitic stainless steel predominantly contains high levels of chromium and nickel. Additional elements may be added to enhance performance. The target of this paper is to melt and cast several austenitic stainless steel alloys with different Nb contents. Furthermore the effects of the chemical composition on strength as well as the effect of cold rolling on the creation of induced martensite phase are also studied. The microstructural investigation shows that grain coarsening was observed on the as-cast structure accompanying with thick grain boundary carbides along with carbide agglomerations at the triple points. Hot deformation diminishes the grains as well as the carbide films surrounding the grains. Solution treatment creates austenitic grains free of grain boundary carbides. Cold deformation creates highly elongated grains associated with wavy pancaked structure. Numerical modeling extensively used to detect the proof strength at high temperatures (up to 600 °C). The detected proof strength decreases drastically by raising the deformation temperatures. Nb was found to increase the proof strength even at high temperatures. The measured mechanical properties of the alloys under investigation are higher than that of detected ones by Kimura model, where the model did not pay attention to the Nb effect. Elliason model for the flow curve of different alloys has been extensively studied and applied. The detected results have been verified by the microstructural changes during deformation. 相似文献
63.
64.
Eman M Taher Tania Veltman Kiro R Petrovski 《International Journal of Dairy Technology》2023,76(1):63-73
High-temperature short-time (HTST) pasteurisation is not sufficient for complete elimination of Bacillus sp. in milk. Hence, it is important to assess their prevalence, phenotypic and genetic antimicrobial resistance profiles in pasteurised milk. In this study, we investigated Bacillus prevalence and their phenotypic resistance to 25 antimicrobials and prevalence of five plasmid antimicrobial resistance genes. All isolates were resistant to β-lactams; most isolates were susceptible to chloramphenicol (n = 52), ciprofloxacin, meropenem, sulphonamides, tetracycline and vancomycin (n = 56). Intriguingly, despite phenotypic sulphonamide and tetracycline sensitivity, Sul2 and tetA genes were detected in different Bacillus species, signifying a potential risk of horizontal gene transfer of these mobile resistance genes through pasteurised milk. 相似文献
65.
Eman Zakaria Gomaa 《Food science and biotechnology》2013,22(2):455-463
The aim of this study was to investigate in vitro antioxidant, antimicrobial, and antitumor activities of water, methanol, and ethanol extracts of sweet apricot and bitter almond kernels. The fruit extracts were evaluated for their antioxidant activities using various antioxidant methodologies including phosphomolybdenum assay (total antioxidant capacity), free radical scavenging assay, ferric ion reducing power, and β-carotene/linoleic acid bleaching test system. The antioxidant capacity of the sweet apricot kernels was better than those recorded for bitter almond ones. The highest total antioxidant activity (59.53 mg/g dry extract), ferric ion reducing power (1.626), antioxidant index (67%), total phenolic content (3.290 mg/g dry extract), and total lycopene content (4.70mg/mL) were detected in the aqueous extract of sweet apricot kernels. The antimicrobial activities of the above extracts were also tested against some pathogenic microorganisms using a disc-diffusion method. Additionally, the extracts of sweet apricot and bitter almond kernels could inhibit the growth of human breast (MCF-7), colon (HCT-116), and hepatocellular (Hep-G2) carcinoma cell lines in a dose-dependent manner with different sensitivity between cell lines. The overall results indicate promising baseline information for the potential uses of apricot (Prunus armeniaca L.) fruit extracts in the treatment of infectious diseases and tumors. 相似文献
66.
为量化0.05 μm陶瓷膜脱除羊乳中乳清蛋白、乳糖、灰分、钙和磷的能力,在50 ℃条件下,脱脂乳进行3 倍浓缩,之后2 次间歇补水至原体积进行清洗过滤,最终得到1 份截留液、3 份透过液,并计算各组分总脱除率。结果表明:乳清蛋白脱除率为96.17%,乳糖脱除率为86.42%,灰分脱除率为73.39%,钙脱除率为34.90%,磷脱除率为55%。稀释过滤完毕后膜的纯水膜通量衰减系数为55.57%,使用质量分数为2%氢氧化钠和1%的硝酸溶液进行清洗,膜通量的恢复系数为99.21%。0.05 μm陶瓷膜可以实现羊乳酪蛋白和其他组分的有效分离,该技术适合在没有干酪乳清的条件下,以生鲜乳为原料加工酪蛋白胶束粉、乳清蛋白粉、乳糖等乳基配料产品。 相似文献
67.
Abdullah S. Alshetaili Bjad K. Almutairy Saad M. Alshahrani Eman A. Ashour Roshan V. Tiwari Sultan M. Alshehri 《Drug development and industrial pharmacy》2016,42(11):1833-1841
The aim of this study was to formulate face-cut, melt-extruded pellets, and to optimize hot melt process parameters to obtain maximized sphericity and hardness by utilizing Soluplus® as a polymeric carrier and carbamazepine (CBZ) as a model drug. Thermal gravimetric analysis (TGA) was used to detect thermal stability of CBZ. The Box–Behnken design for response surface methodology was developed using three factors, processing temperature (?°C), feeding rate (%), and screw speed (rpm), which resulted in 17 experimental runs. The influence of these factors on pellet sphericity and mechanical characteristics was assessed and evaluated for each experimental run. Pellets with optimal sphericity and mechanical properties were chosen for further characterization. This included differential scanning calorimetry, drug release, hardness friability index (HFI), flowability, bulk density, tapped density, Carr’s index, and fourier transform infrared radiation (FTIR) spectroscopy. TGA data showed no drug degradation upon heating to 190?°C. Hot melt extrusion processing conditions were found to have a significant effect on the pellet shape and hardness profile. Pellets with maximum sphericity and hardness exhibited no crystalline peak after extrusion. The rate of drug release was affected mainly by pellet size, where smaller pellets released the drug faster. All optimized formulations were found to be of superior hardness and not friable. The flow properties of optimized pellets were excellent with high bulk and tapped density. 相似文献
68.
Sundari S. Shanmuga Arunadevi N. Kanchana P. Meena P. Kumar E. Ranjith Elansary Hosam O. Mahmoud Eman A. Abdelmohsen Shaimaa A. M. 《Journal of Materials Science: Materials in Electronics》2022,33(22):17421-17433
Journal of Materials Science: Materials in Electronics - Glycine phosphite (GPI), a semi-organic nonlinear optical NLO material, has been synthesized at room temperature. Slow evaporation method... 相似文献
69.
Eman A. Ahmed Marwa O. El-Derany Ali Mostafa Anwar Essa M. Saied Sameh Magdeldin 《International journal of molecular sciences》2023,24(1)
With the rising incidence of hepatocellular carcinoma (HCC) from non-alcoholic steatohepatitis (NASH), identifying new metabolic readouts that function in metabolic pathway perpetuation is still a demand. The study aimed to compare the metabolic signature between NASH and NASH-HCC patients to explore novel reprogrammed metabolic pathways that might modulate cancer progression in NASH patients. NASH and NASH-HCC patients were recruited and screened for metabolomics, and isotope-labeled lipidomics were targeted and profiled using the EXION-LCTM system equipped with a Triple-TOFTM 5600+ system. Results demonstrated significantly (p ≤ 0.05) higher levels of triacylglycerol, AFP, AST, and cancer antigen 19-9 in NASH-HCC than in NASH patients, while prothrombin time, platelet count, and total leukocyte count were decreased significantly (p ≤ 0.05). Serum metabolic profiling showed a panel of twenty metabolites with 10% FDR and p ≤ 0.05 in both targeted and non-targeted analysis that could segregate NASH-HCC from NASH patients. Pathway analysis revealed that the metabolites are implicated in the down-regulation of necroptosis, amino acid metabolism, and regulation of lipid metabolism by PPAR-α, biogenic amine synthesis, fatty acid metabolism, and the mTOR signaling pathway. Cholesterol metabolism, DNA repair, methylation pathway, bile acid, and salts metabolism were significantly upregulated in NASH-HCC compared to the NASH group. Metabolite–protein interactions network analysis clarified a set of well-known protein encoding genes that play crucial roles in cancer, including PEMT, IL4I1, BAAT, TAT, CDKAL1, NNMT, PNP, NOS1, and AHCYL. Taken together, reliable metabolite fingerprints are presented and illustrated in a detailed map for the most predominant reprogrammed metabolic pathways that target HCC development from NASH. 相似文献
70.
Mysoon M. Al-Ansari Shereen M. Aleidi Afshan Masood Eman A. Alnehmi Mai Abdel Jabar Maha Almogren Mohammed Alshaker Hicham Benabdelkamel Anas M. Abdel Rahman 《International journal of molecular sciences》2022,23(17)
Bone mass reduction due to an imbalance in osteogenesis and osteolysis is characterized by low bone mineral density (LBMD) and is clinically classified as osteopenia (ON) or osteoporosis (OP), which is more severe. Multiple biomarkers for diagnosing OP and its progression have been reported; however, most of these lack specificity. This cohort study aimed to investigate sensitive and specific LBMD-associated protein biomarkers in patients diagnosed with ON and OP. A label-free liquid chromatography-mass spectrometry (LC-MS) proteomics approach was used to analyze serum samples. Patients’ proteomics profiles were filtered for potential confounding effects, such as age, sex, chronic diseases, and medication. A distinctive proteomics profile between the control, ON, and OP groups (Q2 = 0.7295, R2 = 0.9180) was identified, and significant dysregulation in a panel of proteins (n = 20) was common among the three groups. A comparison of these proteins showed that the levels of eight proteins were upregulated in ON, compared to those in the control and the OP groups, while the levels of eleven proteins were downregulated in the ON group compared to those in the control group. Interestingly, only one protein, myosin heavy chain 14 (MYH14), showed a linear increase from the control to the ON group, with the highest abundance in the OP group. A significant separation in the proteomics profile between the ON and OP groups (Q2 = 0.8760, R2 = 0.991) was also noted. Furthermore, a total of twenty-six proteins were found to be dysregulated between the ON and the OP groups, with fourteen upregulated and twelve downregulated proteins in the OP, compared to that in the ON group. Most of the identified dysregulated proteins were immunoglobulins, complement proteins, cytoskeletal proteins, coagulation factors, and various enzymes. Of these identified proteins, the highest area under the curve (AUC) in the receiver operating characteristic (ROC) analysis was related to three proteins (immunoglobulin Lambda constant 1 (IGLC1), RNA binding protein (MEX3B), and fibulin 1 (FBLN1)). Multiple reaction monitoring (MRM), LC-MS, was used to validate some of the identified proteins. A network pathway analysis of the differentially abundant proteins demonstrated dysregulation of inflammatory signaling pathways in the LBMD patients, including the tumor necrosis factor (TNF), toll-like receptor (TL4), and interferon-γ (IFNG) signaling pathways. These results reveal the existence of potentially sensitive protein biomarkers that could be used in further investigations of bone health and OP progression. 相似文献