Antibacterial activities of Allium vineale, Chaerophyllum macropodum and Prangos ferulacea

Allium vineale L., Chaerophyllum macropodum Boiss. and Prangos ferulacea (L.) Lindl. have been used for cheese production in Turkiye for many centuries. In addition, it is traditionally believed by localpeople that these plants have antibacterial activity. The purpose of this study was to evaluate the antibacterial activity of these plants. Four solvent extracts (in methanol, ethanol, n-hexane and water) ofthe plants were investigated against Bacillus cereus, Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Salmonella enteritidis and Salmonella typhimurium by using disc diffusion method. The methanol, ethanol and nhexane extracts of all the plants showed antibacterial activity against B. cereus, B. subtilis, M. luteus and S. aureus, while the methanol extract of Allium vineale was also active against P. mirabilis.However, the water extracts of these plants had no antibacterial activity against any of the bacteria tested. The methanol extracts had the higher activity followed by the extracts of ethanol and n-hexane.A. vineale showed the higher antibacterial activity as compared with C. macropodum and P. ferulacea. As a result, organic solvent extracts (especially methanol and ethanol extracts) of these plants can beused as natural antibacterial additives for incorporation in cheese and various food products

Optimal Staffing Policy and Telemedicine

We study the optimal strategy of a specialty hospital in providing traditional face-to-face consultations via experts and remote medical services via tele-specialists. We model the whole system as a queuing problem and provide the optimal staffing policy for this hospital by taking into account the various cost components, such as those for staffing, incorrect treatment, and waiting. We also find the optimal investment in telemedicine technology that offers the best trade-off between the quality and accuracy of telemedicine services and the cost of technology. Under certain conditions, the hospital does not offer any telemedicine services. When it does, it may or may not invest in the most advanced technology available. Finally, we provide the optimal tele-specialist policy of which patients to treat remotely via telemedicine and which patients to refer to the experts for a face-to-face consultation. We show that a policy of treating all patients via tele-medicine is never optimal

Micro Arc Oxidation of Al-4Si, Al-4Mn and Al-4Mg Binary Alloys

Binary synthetic aluminum alloys Al-M (M = Mg, Mn, Si) containing 4 at.% alloying elements as substrate materials were prepared under controlled vacuum/argon atmosphere. The substrates were coated by micro arc oxidation (MAO) method for 120 minutes in aqueous alkaline electrolyte using the same electrical parameters. The phase constituents, chemical composition, surface roughness and the microstructure of the coatings were characterized by XRD, profilometry and SEM-EDS. The average coating thicknesses are 127 μm, 91 μm and 78 μm on Al-4Mn, Al-4Mg and Al-4Si alloys, respectively. All MAO coatings were composed of mullite (3Al₂O₃·2SiO₂) and γ-Al₂O₃ phases. In addition to these phases, α-Al₂O₃ phase, in the form of precipitates, was detected in coatings on Al-4Mn and Al-4Mg alloys. The presence of Si, Mn and Mg was detected in the coatings, depending of the chemical content of the substrate alloys

Plasma Electrolytic Oxidation of Binary Al-Sn Alloys

Binary Al-Sn (1, 2, 4, 6, 8 at.% Sn) synthetic alloys were prepared under vacuum-atmosphere controlled furnace. The Al-Sn alloys were coated by plasma electrolytic oxidation technique for 120 min in aqueous electrolyte containing sodium silicate and potassium hydroxide using the same electrical parameters. The microstructure, surface roughness, phase content and chemical composition of the coatings were characterized by scanning electron microscopy, profilometry and X-ray diffractometry. The coating became porous while coating thickness and surface roughness decreased, with increasing amount of Sn content in Al-Sn alloys. The coating was not formed on the Al-Sn alloy with 8 at.% Sn. Plasma electrolytic oxidation coatings were composed of mainly mullite ($3Al_2O_3$ ·$2SiO_2$), $γ-Al_2O_3$ and $α-Al_2O_3$ up to 4 at.% Sn. The $α-Al_2O_3$ phase formed as precipitate in the inner region of the coating and its amount decreased with Sn amount in the Al-Sn alloys. The $SnO_2$ phase was only detected in the coating of Al-6Sn alloy. Scanning electron microscopy - energy dispersive X-ray spectroscopy results showed that the traces of Sn were evident in the oxide coating along with Al, O, Si, Na, and K. The increasing addition of Sn in the alloys resulted in reduction of the overall microhardness of the coating with decreasing manner from dense inner region to the surface of the coatings

Characterization of Ternary Mg-Sn-Mn Alloys

Ternary Mg-2Sn-Mn (0.5, 1, 2, and 2.5 wt% Mn) alloys were prepared under vacuum/argon atmosphere controlled furnace to investigate their microstructural and mechanical properties as a potential biodegradable implant material. As-cast alloys were heat treated at 550°C for 24 h and then at 300°C for 16 h. The alloys were characterized as-cast and after the heat treatment by optical microscopy, scanning electron microscopy, X-ray diffraction, and microhardness measurement. Mg phase is evident for both as-cast and heat-treated alloys while Mg₂Sn intermetallic phase is detected in all heat treated alloys except Mg-2Sn-0.5Mn. The dendritic microstructure changed to a microstructure with equiaxed grains after the heat treatment. The increase of Mn in ternary Mg-2Sn-Mn alloys resulted in a microstructure composed of smaller grains. Moreover, microhardness of ternary alloys slightly increased with the addition of Mn