Numerical and Experimental Investigation of the Effect on Heat Transfer of Nanofluid Usage in Mini/Micro Channels

I n this study, the thermal performance of Al2 O3 , TiO2 and ZnO nanofluid in horizontal microchannels was investigated experimentally and numerically. Al2 O3 13nm , TiO2 10-25nm and ZnO 18nm nanoparticles in water to prepare nano-powders with 0.5%, 0.7% and 1.0% volumetric concentration.A set of experiments was set up for experimentation. For this purpose, micro-channels of 20 cm in length were used at different surface temperatures 15, 25, 40 ° C from different materials 400, 750, 1000 μm . In addition, nanofluids with different inlet temperatures, volumetric flow rates 20, 35, 50 mL/min and concentration ratios are used using nanofluids. Temperature, flow and pressure measurements are based on heat transfer, heat transfer coefficient, Nusselt number, pressure drop and friction factor. The values required for the calculations are measured separately. The effects of parameters such as microchannel diameter, particle type, flow velocity and volumetric ratio on the friction factor, temperature distribution, pressure drop, Reynolds and Nusselt numbers with Taguchi method will be determined in the flow program and compared with the experimental study. In addition, this study will be a preliminary model for the design and analysis of new generation cooling radiators with nanofluid which are not used in diesel engines conforming to Euro 5/6 emissions norms

Aorta abdominalis ve dallari: Otopsi olgularında morfometri ve varyasyonları]

Aim: Knowing the morphology of abdominal aorta (AA) and its branches are important as regards to diagnosis and surgical treatment. The aims of this study were to a) make morphometric measurements of AA and its branches, b) to investigate sites of the origins of the branches and their relationships and variations, and c) to compare the results with literature.Method: Ninety-five AA which had been removed in autopsies were measured with caliper morphometrically to determine diameters of branches and distances between branches. Possible variation of the vessels were investigated and photographed.Result: It was found that diameters of celiac trunk (CT), superior mesenteric artery (SMA) and inferior mesenteric artery (IMA) were 6.43±1.59 mm, 7.38±1.67 mm and 3.61±0.72 mm respectively. The distances between CT and aortic bifurcation (AB), CT and SMA, SMA and IMA, IMA and AB were 107.21±11.46 mm, 14.34±2.67 mm, 57.76±8.04 mm, 35.20±7.41 mm respectively. Numerous variations were observed during the study. These variations involved inferior phrenic artery (single trunk arising from CT, 4.2%), renal artery-RA (duplicated right RA 9.5%, duplicated left RA 4.2%, bilaterally duplicated 3.1%, %16.8 total multiple RA), gonadal arteries-GA (single GA, 1%), lumbar arteries-LA (3 pairs of LA 11.5%, 3rd or 4th LA arising as single trunk 3.1%) and median sacral artery (agenesis 2.1%). Conclusion: Knowledge of morphology of AA and its branches is important in regards to the diagnosis, surgical treatment and endovascular interventions of these vessels. We think our study will contribute to the medical education and clinical medicine in our country

Tranexamic acid has positive effect in early period of tenaon healing by stimulating the tumor necrosis factor-alpha and matrix metalloproteinase-3 expression levels

Objectives: This study aims to evaluate the effect of tranexamic acid (TXA) application in tendon healing by using its immunohistochemical effects on tumor necrosis factor-alpha (TNF-alpha), matrix metalloproteinase-3 (NIMP-3), and transforming growth factor-beta (TGF-beta) expression; and to identify if TNF-alpha, MMP-3, and TOF-beta can be used to monitor and evaluate tendon healing or not in tenotomized rat Achilles tendons

Serum Growth Arrest Specific Protein 6 (Gas-6) Levels in Patients with Schizophrenia

Objective: We have investigated serum growth ar­rest-specific protein 6 (GAS-6) levels from patients with schizophrenia divided into acute phase remission phases as well as control group. Methods: This study was conducted in Psychiatry De­partment of Istanbul University Cerrahpasa Medical Fac­ulty. The patients who were diagnosed with schizophrenia after regular psychiatric examination according to DSM-IV criteria (n=22) as well as control subjects were includ­ed in the study. Schizophrenia patients with acute phase and remission phase were evaluated by Positive and Negative Syndrome Scale (PANSS) and Clinical global Impression Scale (CGI-S). The serum GAS-6 levels of schizophrenia patients during acute phase and remission phase were compared with the serum GAS-6 levels of healthy controls. Serum GAS-6 levels were measured by commercial ELISA kits. Results: No difference was found in serum GAS-6 levels among the three groups; schizophrenia with acute phase, schizophrenia with remission phase, and controls. There were no correlations between serum GAS-6 levels and PANSS and CGI scores. Conclusion: To reach a definitive data and better in­terpretation about the relationship between GAS-6 and schizophrenia, future studies with larger groups of pa­tients with schizophrenia subdivided by drug naïve and treated with antipsychotics/other treatment modalities and controls are needed

Oroantral Açıklıkların Okluzal Splintler ile Cerrahisiz Kapatılması

Purpose: Oroantral communications (OACs) may close spontaneously, especially when the defect has a size smaller than 2-3 mm, whereas larger openings require surgical closure. The aim of this retrospective study was to present our experince with non surgical closure of small and large OACs with occlusal splints. Materials and Methods: Clinical and radiographic data of twenty patients who had used occlusal splints after the occurance of an acute OAC were included in this study. Two groups were created according to the size of the defects: Group A: defects smaller (<) than 5 mm; and Group B: 5 mm and wider (≥). In all patients, a well fitted soft occlusal splint was placed for hermetic closure of the opening.  All patients were followed up weekly and the splint use was stopped when complete epithelization of the OAC was observed clinically. The relationship between the size of OACs, treatment outcome, and healing time was compared statistically. Results: OAC was healed spontaneously in all patients, except one. The healing time was found to be significantly higher in goup B than in group A. No significant difference was found between the groups with respect to the success of the treatment. Conclusion: The use of occlusal splints seems to improve the spontaneus healing of the OACs