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321.
The aim of this study was to investigate the presence of Staphylococcus aureus and staphylococcal enterotoxin (SE) genes in Urfa cheese samples and to characterize the enterotoxigenic potential of these isolates. From a total of 127 Urfa cheese samples, 53 isolates (from 41.7% of the samples) were identified by a species-specific PCR assay as S. aureus. Of these isolates, 40 (75.5%) gave positive PCR results for the 3' end of the coa gene. The coa-positive S. aureus strains were characterized for their population levels and enterotoxigenic properties, including slime factor, β-lactamase, antibiotic susceptibilities, production of the classical SEs (SEA through SEE), in both cheese and liquid cultures by enzyme-linked immunosorbent assay (ELISA) and for the presence of specific genes, including classical SE genes (sea through see), mecA, femA, and spa, by PCR. The genetic relatedness among the coa-positive S. aureus isolates was investigated by PCR-based restriction fragment length polymorphism (RFLP) analysis and the 23S rRNA gene spacer. The 23S rRNA gene spacer and coa RFLP analysis using AluI and Hin6I revealed 14 different patterns. SEB, SEC, and SEA and SEE were detected by ELISA in three cheese samples. Fourteen S. aureus strains harbored enterotoxin genes sea through see, and three strains carried multiple toxin genes. The most commonly detected toxin gene was sec (25% of tested strains). Of the 40 analyzed S. aureus strains, 3 (7.5%) were mecA positive. Based on tandem repeats, four coa and spa types were identified. The results of this study indicate that S. aureus and SEs are present at significant levels in Urfa cheese. These toxins can cause staphylococcal food poisoning, creating a serious hazard for public health. 相似文献
322.
Due to the differences in physical, chemical and mechanical properties of the base metals, the resistance spot welding of dissimilar materials is generally more challenging than that of similar materials. The influence of the primary welding parameters affecting the heat input such as peak current on the morphology, microhardness, and tensile shear load bearing capacity of dissimilar welds between 304 grades austenitic and 7114 grade interstitial free steel has been investigated in this study. The optimum welding parameters producing maximum joint strength were established at a peak current of 9 kA, where the electrode force is kept 6×10-5 Pa and weld time is kept constant 17 cycles, respectively. The primary cause of weakening the weldment is identified as the excessive grain growing region of heat affected zone (HAZ) in case of 7114 grade interstitial free steel. 相似文献
323.
Mustafa Yi
i
tolu Mustafa Ersz Ramazan Cokun Oya anli Halil I
brahim Ünal 《应用聚合物科学杂志》1998,68(12):1935-1939
The adsorption behavior of poly(ethylene terephthalate) (PET) fibers towards copper(II), cobalt(II), and iron(III) ions in aqueous solutions was studied by a batch equilibriation technique. Influence of treatment time, temperature, pH of the solution, and metal ion concentration on the adsorption were investigated. Adsorption values for metal ion intake followed the following order: Co(II) > Cu(II) > Fe(III). One hour of adsorption time was found sufficient to reach adsorption equilibrium for all the ions. The rate of adsorption was found to decrease with the increase in the temperature. Langmuir adsorption isoterm curves were found to be significant for all the ions studied. The heat of adsorption values were calculated as −5, −2.8, and −3.6 kcal/mol for Cu(II), Co(II), and Fe(III) ions, respectively. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1935–1939, 1998 相似文献
324.
Virtual Reality - This study aims to fill a gap in current research on virtual reality (VR) by developing a valid and reliable educational VR acceptance scale based on the unified theory of... 相似文献
325.
Karaoglan-Yilmaz Fatma Gizem Yilmaz Ramazan Zhang Ke Ustun Ahmet Berk 《Virtual Reality》2023,27(3):1875-1885
Virtual Reality - The aim of the study is to address a gap in the literature by developing an educational virtual reality (edVR) attitude measurement instrument, which determines college... 相似文献
326.
Seewoogolam Vibhakar Prasad Brijesh Manral Avi Raj Alarifi Ibrahim M. Asmatulu Ramazan 《Journal of Mechanical Science and Technology》2022,36(1):99-108
Journal of Mechanical Science and Technology - Micro air vehicles (MAVs) are small portable flying machines designed to perform some specific tasks. Presently, the MAVs are being highly considered... 相似文献
327.
Universal Access in the Information Society - This study examines the effects of using learning analytics (LA) in a mobile-based learning setting on students' self-regulated learning (SRL)... 相似文献