Comparative study of turbulent flow around a bluff body by using two- and three-dimensional CFD

Ozdogan, Muhammet,Sungur, Bilal,Namli, Lutfu,Durmus, Aydin Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.25 No.6

In this study, the turbulent flow around a bluff body for different wind velocities was investigated numerically by using its two- and three-dimensional models. These models were tested to verify the validity of the simulation by being compared with experimental results which were taken from the literature. Variations of non-dimensional velocities in different positions according to the bluff body height were analysed and illustrated graphically. When the velocity distributions were examined, it was seen that the results of both two- and three-dimensional models agree with the experimental data. It was also seen that the velocities obtained from two-dimensional model matched up with the experimental data from the ground to the top of the bluff body. Particularly, compared to the front part of the bluff body, results of the upper and back part of the bluff body are better. Moreover, after comparing the results from calculations by using different models with experimental data, the effect of multidimensional models on the obtained results have been analysed for different inlet velocities. The calculation results from the two-dimensional (2D) model are in satisfactory agreement with the calculation results of the three-dimensional model (3D) for various flow situations when comparing with the experimental data from the literature even though the 3D model gives better solutions.

Liver fibrosis in children: a comprehensive review of mechanisms, diagnosis, and therapy

Ozdogan Elif,Arikan Cigdem 대한소아청소년과학회 2023 Clinical and Experimental Pediatrics (CEP) Vol.66 No.3

Chronic liver disease incidence is increasing among children worldwide due to a multitude of epidemiological changes. Most of these chronic insults to the pediatric liver progress to fibrosis and cirrhosis to different degrees. Liver and immune physiology differs significantly in children from adults. Because most of pediatric liver diseases have no definitive therapy, a better understanding of population and disease-specific fibrogenesis is mandatory. Furthermore, fibrosis development has prognostic significance and often guide treatment. Evaluation of liver fibrosis continues to rely on the gold-standard liver biopsy. However, many high-quality studies put forward the high diagnostic accuracy of numerous diagnostic modalities in this setting. Herein, we summarize and discuss the recent literature on fibrogenesis with an emphasis on pediatric physiology along with a detailed outline of disease-specific signatures, noninvasive diagnostic modalities, and the potential for antifibrotic therapies.

The effects of repetitive firing processes on the optical, thermal, and phase formation changes of zirconia

Ozdogan, Alper,Ozdemir, Hatice The Korean Academy of Prosthodonitics 2020 The Journal of Advanced Prosthodontics Vol.12 No.1

PURPOSE. The aim of this study was to investigate the effect of different numbers of heat treatments applied to superstructure porcelain on optical, thermal, and phase formation properties of zirconia. MATERIALS AND METHODS. Forty zirconia specimens were prepared in the form of rectangular prism. Specimens were divided into four groups (n = 10) according to the number of firing at heating values of porcelain. Color differences and translucency parameter were measured, and X-ray diffraction (XRD) analysis and differential scanning calorimetry (DSC) were performed. Data were analyzed with analysis of variance (ANOVA). RESULTS. There were no statistically significant differences in ∆E, TP, L, a, and b value changes of the zirconia specimens as a result of repetitive firing processes (P>.05). CONCLUSION. Although additional firing processes up to 4 increase peak density in thermal analysis, additional firing processes up to 4 times can be applied safely as they do not result in a change in color and phase character of zircon frameworks.

Comparative study of turbulent flow around a bluff body by using two- and three-dimensional CFD

Muhammet Ozdogan,Bilal Sungur,Lutfu Namli,Aydin Durmus 한국풍공학회 2017 Wind and Structures, An International Journal (WAS Vol.25 No.6

In this study, the turbulent flow around a bluff body for different wind velocities was investigated numerically by using its two- and three-dimensional models. These models were tested to verify the validity of the simulation by being compared with experimental results which were taken from the literature. Variations of non-dimensional velocities in different positions according to the bluff body height were analysed and illustrated graphically. When the velocity distributions were examined, it was seen that the results of both two- and three-dimensional models agree with the experimental data. It was also seen that the velocities obtained from two-dimensional model matched up with the experimental data from the ground to the top of the bluff body. Particularly, compared to the front part of the bluff body, results of the upper and back part of the bluff body are better. Moreover, after comparing the results from calculations by using different models with experimental data, the effect of multidimensional models on the obtained results have been analysed for different inlet velocities. The calculation results from the two-dimensional (2D) model are in satisfactory agreement with the calculation results of the three-dimensional model (3D) for various flow situations when comparing with the experimental data from the literature even though the 3D model gives better solutions.

In Vitro Antimicrobial Effect of Satureja wiedemanniana Against Bacillus Species Isolated from Raw Meat Samples

Yuce, Nihal,Aslim, Belma,Ozdogan, Hakan The Korean Society of Food Science and Nutrition 2009 Journal of medicinal food Vol.12 No.4

In this study a total of 30 raw meat samples obtained from Ankara, Turkey were screened for the presence of Bacillus species. Among the meat samples analyzed, the predominant species isolated was Bacillus circulans; other Bacillus species were identified as Bacillus firmus, Bacillus lentus, Bacillus megaterium, Bacillus licheniformis, Bacillus mycoides, Bacillus sphaericus, and Bacillus cereus. Minced meat samples were more contaminated with Bacillus species than sliced beef sample. From these samples, 242 Bacillus species isolates were obtained, which were investigated for proteolytic and lipolytic activity, associated with meat spoilage. Interestingly, some Bacillus strains produced the highest values of proteolytic/lipolytic activities. Nineteen Bacillus strains were selected among the 242 isolates according to their proteolytic/lipolytic activity with a clear zone diameter of ${\geq}6\;mm$. The essential oil of Satureja wiedemanniana (Lalem) Velen was also tested against these 19 Bacillus species that had proteolytic and lipolytic activity. The essential oil yield obtained from the aerial parts of the plant was 0.35% (vol/wt). The inhibition zones of the essential oil obtained against all the Bacillus species were in the range of 5.0.12.0 mm. The oil showed high antimicrobial activities against B. licheniformis M 6(26), M 11(16), and M 12(1) strains. B. licheniformis 12(1) showed high lipolytic activity (18.0 mm). Also, B. licheniformis M 6(26) and M 11(16) showed high proteolytic activity (16.0 and 14.0 mm). These results may suggest that an essential oil of S. wiedemanniana can be used as a natural preservative in meat against spoilage bacteria.

Comparison of the Practical and Theoretical Knowledge of the Hepatitis B Virus among Dental Hygiene Students

( Sinan Yasin Ertem ),( Sertac Ozdogan ),( Ayla Ozturk ),( Ozge Akcam ) 한국치위생과학회 2020 치위생과학회지 Vol.20 No.3

Background: Hepatitis B is an important public health problem as one of the leading causes of morbidity and mortality. The aim of this study was to compare the theoretical and practical knowledge levels of dental assistant students about Hepatitis B Virus. Methods: The 1st and 2nd grade students of the Oral and Dental Health program were invited to participate in the survey. Out of the 68 invited students, 61 completed the questionnaire. The average ages of the male and female students surveyed were 20.27±1.45 and 19.56±1.16, respectively. A total of 34 questions were asked, of which 15 measured basic theoretical knowledge and 19 assessed basic practical knowledge. Results: There was no statistically significant difference between the students’ knowledge for each question according to their sex and grade. When the questionnaire was grouped into basic theoretical and basic practical knowledge levels, both were observed to be high. While the lowest correct answer rate was 35.00% for the questions about practical applications, it was 31.14% for the questions measuring the level of theoretical knowledge. There was no statistically significant difference when the levels of knowledge of 1st and 2nd grade students were compared. Students answered the majority of the questions correctly, and ranged between 71% and 100%. Conclusion: Students’ high level of basic theoretical knowledge can be a result of their in-class education on the fundamentals. However, their knowledge about the correct approaches in practical applications indicates the beneficial role of having well-defined criteria and prevention protocols that are required in hospitals and the effectiveness of their environmental orientations.

Efficacy and Safety of Intravitreal Dexamethasone Implants for Treatment of Refractory Diabetic Macular Edema

Erkan Unsal,Kadir Eltutar,Pınar Sultan,Sezin Ozdogan Erkul,Ozen Ayranci Osmanbasoglu 대한안과학회 2017 Korean Journal of Ophthalmology Vol.31 No.2

Purpose: To evaluate the safety and efficacy of intravitreal dexamethasone (IVD) implants in eyes with diabeticmacular edema that did not respond to previous treatment. Methods: We included 46 eyes of 46 patients in this retrospective study. Each month, we recorded patient visualacuity with logarithm of the minimum angle of resolution using the Early Treatment Diabetic RetinopathyStudy chart, central macular thickness measurements with optical coherence tomography, intraocular pressure(IOP), and posttreatment complication occurrence. Results: The mean follow-up time was 8.95 ± 1.33 months (range, 6 to 12). Best-corrected visual acuity improvedsignificantly in the first 4 months after IVD, but no statistically significant change was observed over the following2 months. Although a statistically significant decrease in central macular thickness was observed in thefirst 3 months, the change was not statistically significant in the following 3 months. There was a statisticallysignificant increase in IOP in the first 2 months, but no statistically significant change was observed in the followingmonths. IOP was controlled with medication in all patients with elevated IOP. Of the 26 phakic patients,two had cataracts requiring surgery. Conclusions: Cases of refractory diabetic macular edema that did not respond to previous treatment, such asanti-vascular endothelial growth factor injections and laser photocoagulation, exhibited improvements in visualacuity and decreases in retinal thickness after IVD implantation. Both functional and anatomical effects wereobserved in the first 3 months after injection. Repeat injections and frequent examination might be required forcontinued improvement. Side effects, such as cataracts and elevation of IOP, may require medical or surgicaltreatment.

Is Sunlight a Predisposing Factor for Triple Negative Breast Cancer in Turkey?

Mutlu, Hasan,Buyukcelik, Abdullah,Colak, Taner,Ozdogan, Mustafa,Erden, Abdulsamet,Aslan, Tuncay,Akca, Zeki Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.2

Intraduction: There is known to be a relationship between vitamin D level and more aggresive breast cancer subtypes, especially triple-negative breast cancer (TNBC). It was reported that sunlight exposure has an effect on the prognosis of patients with cancer, possibly related to the conversion of vitamin D to its active form with sunlight. We aimed to evaluate the effect of sunlight exposure on patients with TNBC. Materials-Methods: A total of 1,167 patients with breast cancer from two different regions of Turkey (Antalya and Kayseri, regions having different climate and sunlight exposure intensity over the year) were analysed retrospectively. The ratio of patients with TNBC was identified in those two regions. Results: The ratio of patients with TNBC was 8% and 12% for Kayseri and Antalya regions, respectively, and this difference between the two groups was statistically significant (p=0.021). Discussion: Sunlight exposure may be associated with more prevalent TNBC. This finding should be investigated with a prospective study.

Vaginal cancer as a late complication of radiotherapy for endometrial cancer and ileo-perineal fistula after total pelvic exenteration

Cihan Comba,Merve Topaktas,Hilmi Bozkurt,Akif Erbin,Burcu Ozdogan,Omer Demir 대한부인종양학회 2021 Journal of Gynecologic Oncology Vol.32 No.4

Pelvic exenteration is a highly morbid operation and remains one of the most catastrophic surgical procedures in gynecological oncology. We would like to present the case oftotal pelvic exenteration for vaginal cancer after radiotherapy for endometrial cancer asa secondary cancer. A 62-year-old woman, whose gravida: 3, parity: 2, body mass index:35.9 kg/m2, presented with complaints of vaginal bleeding. She had undergone a surgery because of a stage IB grade 2 endometrioid-type adenocarcinoma seventeen years previously. Following the surgery, she had external pelvic radiotherapy and brachytherapy. A palpable, solid and ulcerative mass was detected extending from the vaginal cuff area to the vestibulum vagina on the left postero-lateral wall of the vagina. The 5-cm vaginal mass was seen at vaginal examination. A punch biopsy from a pathological examination of the tumoral lesion was reported as a squamous cell carcinoma. Pelvic exenteration was performed and ileo- perineal fistula occurred after six months this surgery. In conclusion, we considered that this malignancy was a secondary malignancy induced by radiotherapy.

Growth rate, carcass characteristics and meat quality of growing lambs fed buckwheat or maize silage

Keles, Gurhan,Kocaman, Veli,Ustundag, Ahmet Onder,Zungur, Asli,Ozdogan, Mursel Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.4

Objective: This study evaluated inclusion of buckwheat silage to the diet of growing lambs in terms of meat quality as compared to maize silage. Methods: Buckwheat, rich in total phenols (TP, 33 g/kg dry matter [DM]), was harvested at the end of the milk stage and ensiled in 40 kg plastic bags after wilting (294 g/kg silage DM). A total of 18 growing lambs ($21.6{\pm}1.2$) were individually fed isonitrogenous and isoenergetic total mixed rations (TMR) for 75 d that either contained buckwheat or maize silage at DM proportions of 0.50. At the end of feeding trail all lambs were slaughtered to assess carcass characteristics and meat quality. Results: Buckwheat silage increased (p<0.01) the DM intake of lambs as compared to maize silage, but had no effects (p>0.05) on live weight gain and feed efficiency. Carcass weight, dressing percentage, meat pH, water holding capacity, cooking loss, shear force ($kg/cm^2$), and total viable bacteria count of meat did not differ (p>0.05) between the treatments. However, TP content of meat increased (p<0.001) by feeding buckwheat TMR. Feeding buckwheat TMR also decreased (p<0.05) the b* values of meat. Conclusion: The results provide that buckwheat silage is palatable and could successfully include TMR of growing lambs with no adverse effects on performance, carcass and meat quality. Additionally, feeding buckwheat silage to lambs offers increased TP in meat.