Micro electro discharge machining of tungsten carbide and polycrystalline diamond : an experimental analysis of process parameters

Ankara : The Department of Industrial Engineering and the Graduate School of Engineering and Science of Bilkent Univ., 2013.Thesis (Master's) -- Bilkent University, 2013.Includes bibliographical references leaves 62-64.Electro discharge machining (EDM) is a manufacturing process where material removal is realized through electrical discharges between two conductive materials without applying any external forces. As a result, high aspect ratio micro features on difficult-to-cut materials such as tungsten carbide and polycrystalline diamond can be obtained. In this study, influences of micro-EDM process parameters such as voltage, capacitance, and rotational speed on material removal rate and surface quality have been investigated using experimental techniques. Experimental results have revealed that capacitance and voltage applied during EDM process have significant effects on material removal rate and surface roughness. Regression models have been calculated to represent the relationships between process inputs and outputs which can be used to calculate processing time and to predict surface finish. In addition, a process planning software for wire-EDM process, which is capable of generating necessary tool paths during fabrication of micro tools, has been developed. The software is also capable of producing the solid model of the micro tools which can be utilized in computer aided engineering applications.Özdemir, CemM.S

The protective effect of docosahexaenoic acid on the bilirubin neurotoxicity

Usually, all newborns demonstrate high serum unconjugated bilirubin (UCB) level. UCB may induce adverse effects in the central nervous system. We aimed to evaluate the cytotoxic effects of UCB and the protective effects of docosahexaenoic acid (DHA) on astrocyte cell cultures. The viability of astrocyte cells decreased after UCB treatment in a dose-dependent manner. Pre-incubation of DHA prevents the cells from UCB-mediated neurotoxicity. Our results shown that UCB leads to inhibition of antioxidant enzymes superoxide dismutase (SOD), catalase and GPx activity and induction of apoptosis. But only 4-h pretreatment of DHA can suppress of UCB-mediated inhibition of antioxidant enzymes SOD, catalase and GPx activity and induction of apoptosis in astrocytes. Our results strongly indicated that DHA has a protective effect on UCB-mediated neurotoxicity through inhibition apoptosis and antioxidant enzymes activity of SOD, CAT and GPx in rat primer astrocyte cell line © 2013 Informa UK, Ltd

Clustering Nuts Level 2 Regions By K-Means and trimmed K means methods according to household consumption expenditures

Mevcut çalışmada, Türkiye’de, tüketim harcamalarına göre benzer bölgelerin belirlenmesi amaçlanmıştır. Bu bağlamda, Türkiye İstatistik Kurumu’nun (TÜİK) yayınlamış olduğu Hanehalkı Tüketim Harcamasının verileri kullanılmıştır. İlgili veride gıda ve alkolsüz içecekler, alkollü içecekler, sigara ve tütün, giyim ve ayakkabı, konut ve kira, mobilya, ev aletleri ve bakım hizmetleri, sağlık, ulaştırma, haberleşme, eğlence ve kültür, eğitim hizmetleri, lokanta ve oteller, çeşitli mal ve hizmetler olmak üzere toplamda 12 harcama mevcuttur. Ayrıca veride, TÜİK’in belirlediği Türkiye İstatistiki Bölge Birimleri Sınıflandırması Düzey 2 bölgeleri yer almaktadır. Benzer bölgelerin belirlenmesi için kümeleme yöntemlerinden k-ortalamalar ve k kırpılmış ortalamalar kullanılmıştır. K-ortalamalar yönteminde küme sayısının belirlenmesi için ise Silhouette İndeksinden yararlanılmıştır. Analiz sonucunda 3 küme olduğu tespit edilmiş ve sırasıyla kümelerde 4, 4 ve 18 bölge yer almıştır. K kırpılmış ortalamalar analiz sonucuna göre 3 küme olduğu tespit edilmiş ve sırasıyla kümelerde 4, 10 ve 11 bölge yer almıştır TR10 (İstanbul) aykırı gözlem olarak belirlenmiştir.This paper attempts to determine similar regions in Turkey according to consumption expenditures. For this reason, the data used in the analysis was gathered from Turkish Statistical Instıtute, Household Consumption Expenditures research. In the data, there were 12 variables: food and non-alcoholic beverages, alcoholic beverages, cigarettes, clothing and foot wear, housing and rent, furniture, house appliances, health, transportation, communication, entertainment and culture, educational services, restaurants, food services and hotels, various goods and services. Moreover, NUTS Level 2 regions was analyzed. In order to determine similar regions, k-means and k-trimmed means from clustering methods were used. The Silhouette Index was used to determine the number of clusters in the k-means method. As a result of the analysis, it was determined that there were 3 clusters and there were 4, 4 and 18 regions in the clusters, respectively. According to the results of the trimmed k-means analysis, it was determined that there were 3 clusters and there were 4, 10 and 11 regions in the clusters, respectively. TR10 (Istanbul) was determined as outlier

Evaluation of the awareness of the physicians on negligence and abuse of the elderly patients admitted to emergency department

Introduction: With the increase in the population of the elderly, the negligence and abuse of the elderly (NAE) is increasing at a great pace. Although the rates of NAE in the elderly admitted to emergency depart- ment (ED) is more than the estimated rates, the diagnosis and reporting of such cases are extremely rare. The primary aim of the present study is to evaluate the NAE status in the elderly admitted to ED, the awareness in ED physicians, the attitudes towards these cases and the knowledge levels in this field.  Methods: An electronic questionnaire form that was used as the data collection tool consisted of 19 ques- tions and 2 sections. To call for participation, the questionnaires used in the study were shared with the ED physicians in an online manner between December 2017 and April 2018. The data were analyzed with the SPSS 23.0 Windows computer program with definitive statistics.  Results: A total of 69.4% of the participants faced NAE and 30% did not report this; 79.8% of the partic- ipants stated that they had received training in this field and 9% stated that there was a screening test for the abuse of the elderly. A statistically significant difference was determined between those who received course training in this field and those who received training during medicine faculty education and specialist training.  Conclusions: In this study, it was observed that the NAE rates were more than the estimated rates in the elderly admitted to ED. It was understood that ED physicians did not have adequate knowledge in this field. A new curriculum is needed for the training and education in this field. 

Histomorphological features of atypical small acinar proliferations (ASAP) that favor malignancy

Objective: Cases diagnosed as atypical small acinar proliferation (ASAP) in prostate transrectal ultrasound (TRUS) biopsies typically require rebiopsies, which are invasiveand associated with increased risk of complications. Therefore, reduction in the rates of ASAP diagnoses during initial biopsy interpretation will decrease the need forrebiopsy and limit the burden of new diagnostic procedures. The current study aimed to investigate patient demographics, serum PSA levels, and histopathological features of cases identified as “ASAP” during initial prostate biopsies and as “benign” or “malignant” in the rebiopsies. Methods: This retrospective study included 187 cases and 257 core biopsies with a diagnosis of ASAP. Initial age and serum PSA levels were recorded, and the cores were analyzed histopathologically. The presence of nuclear enlargement, prominence of nucleoli, cytoplasmic amphophilia, luminal acellular secretions, cristalloids, infiltrative growth pattern, atrophy, inflammation, and number of the suspicious acini were recorded. Adenocarcinomas were identified using the Gleason score. Results: The mean age and serum PSA levels were significantly higher in the intermediate- high grade malignant group compared to the other groups, while nuclear enlargement (>2 times) and prominent nucleoli were more frequently observed in the malignant group compared to the benign group. Amphophilic cytoplasm and luminal acellular amorphous eosinophilic secretions were more frequently observed in malignant groups, while the benign group exhibited higher rates of inflammation. Conclusion: The findings of the current study showed enlargement of the nuclei (≥2 times), nucleolar prominence, amphophilic cytoplasm, luminal amorphous acellular secretion, and absence of inflammation were associated with malignancy. Moreover, higher mean age and serum PSA level were related with intermediate-high grade malignancy, and consideration of these factors during evaluation of initial TRUS biopsies may decrease the prevalence of ASAP diagnoses and prevent unnecessary interventions

Fistula Campaigns-Are They of Any Benefit?

Objective Evaluation of the problems encountered during a voluntarily fistula campaign in a regional hospital of Niger (Africa) Materials and Methods Women underwent basic gynecological examination, methylene blue testing, and/or direct cystoscopy as necessary According to their clinical condition, women were informed and surgical options offered as appropriate Operations were performed under spinal or epidural anesthesia Immediate postoperative outcomes were followed during the stay of the surgical team in the country Results A total of 62 women were examined and 11 had causes of incontinence other than obstetric fistula In 9 8% of the women, severe local infection precluding any surgical intervention was evident In 58 8% of patients, the trigonal region and/or urethra were irreversibly damaged A proportion of patients (9 8%) with large lesions and intact urethra that were offered vaginal layered closure refused the intervention Of the women that were operated on (21 6%), six underwent vaginal layered closure with Martius fat flap and five women underwent a combined abdomino vaginal approach Conclusion It is extremely difficult to meet the needs of this global problem with short term programs and volunteers Directing these efforts to specialist fistula centers and creating reliable scientific evidence should be the main goal [Taiwan J Obstet Gynecol 2010,49(3) 291-296

Clinical and pathological features of adrenal myelolipoma and myelolipomatous metaplasia cases in our hospital over 13 years

BACKGROUND/AIMS: The development and widespread use of abdominal imaging techniques has increased the incidence of unexpected adrenal tumors called adrenal incidentaloma. Adrenal myelolipomas are the second most common incidentalomas. Similar myelolipomatous morphology appears as a secondary degenerative change in other adrenal lesions and is called myelolipomatous metaplasia. This study investigated the adrenal entities of the last 13 years which had myelolipomatous components.MATERIALS AND METHODS: In this retrospective observational study, cases diagnosed as adrenal myelolipoma or myelolipomatous metaplasia between January, 2009 and January, 2022 were re-examined regarding their age, gender, localization, lesion size, and secondary histopathological changes, accompanying pathological diagnoses as well as clinical and radiological data.RESULTS: Eleven adrenal myelolipoma cases and 6 myelolipomatous metaplasia cases were detected. In myelolipomas, the mean age was 55.45 years, 73% were female and 82% were located on the right side. The lesions were encapsulated and their mean size was 7 cm. One case had a diagnosis of subclinical Cushing's syndrome and the others were hormonally inactive. Some cases were accompanied with hypertension (27%), type 2 diabetes (18%), and asthma (18%). All myelolipomatous metaplasias, which are non-encapsulated, were detected in adrenocortical adenomas. The mean age was 58 years; nonencapsulated and 67% were located on the right side with no gender predilection. Concomitant hypertension (50%), diabetes /33%, and asthma (33%) were frequent.CONCLUSION: Adrenal myelolipoma and myelolipomatous metaplasia both contain adipose and myeloid components. Myelolipoma is a benign and encapsulated neoplasia which is usually detected incidentally. They frequently coexist with chronic diseases such as hypertension, diabetes and asthma

Elit altı sporcularda vücut kompozisyonu, anaerobik performans ve sırt kuvveti arasındaki ilişkinin belirlenmesi

The purpose of this study was to determine the relationship among age, height, body weight, body fat percentage, long jump (standing), vertical jump, 20 meter sprint, back strength, relative strength and anaerobic power characteristics of the 80 sub-elit male athletes who are students at a physical education and sports department and participate competitions.  In this study, 80 male students at 22.17 ± 1.97 average age who have been doing exercises regularly, were participate as voluntary. Firstly, their age, height, body weight and skin fold values were determined. Body fat percentage was estimated by Zorba Formula. Anaerobic performance was determined via long jump (standing), vertical jump and 20 meter sprint. Relative strength was estimated with “back strength / body weight” formula. Then, the relationships among body composition, anaerobic performance and back strength characteristics of the participants were determined by Pearson correlation analysis. Analyses of collected data were used by SPSS for Windows (Ver. 10) and alpha level was set as 0.05 for statistical significance.Correlation analysis’ results indicated that there were statically significant correlations among lots of physical and physiological parameters. In conclusion; it was determined that height, body weight, body fat percentage and back strength were played an explicit role on anaerobic performance of athletes.Bu çalışmanın amacı; bir üniversitenin beden eğitimi ve spor yüksek okulunda öğrenim gören bir grup elit-altı sporcunun yaş, boy uzunluğu, vücut ağırlığı, vücut yağ oranı, durarak uzun atlama, dikey sıçrama, 20 metre sprint, sırt kuvveti, relatif kuvvet ve anaerobik güç özellikleri arasındaki ilişkinin belirlenmesidir. Çalışmaya; düzenli antrenman yapan ve müsabakalara katılan beden eğitimi ve spor yüksek okulu (BESYO) öğrencisi, yaş ortalaması 22.17±1.97 yıl olan toplam 80 erkek sporcu gönüllü olarak katılmıştır. Çalışmaya katılan deneklerin boy uzunluğu, vücut ağırlığı, deri kıvrım kalınlığı ölçümleri yapılmıştır. Vücut yağ yüzdesi Zorba formülü kullanılarak belirlenmiştir. Anaerobik performans ise dikey sıçrama, durarak uzun atlama ve 20 metre sürat testleri ile belirlenmiştir. Relatif kuvvet, sırt kuvvetinin vücut ağırlığına bölünmesi ile bulunmuştur. Katılımcıların vücut kompozisyonu, anaerobik performans ve sırt kuvveti arasındaki ilişkinin belirlenmesi amacıyla verilerin analizinde “Pearson Çarpımlar Moment Korelasyon Analizi” kullanılmıştır. Analizler Windows için SPSS (ver. 10) paket programı ile yapılmış ve istatistiksel anlamlılık düzeyi 0,05 olarak kabul edilmiştir.Korelasyon analizleri sonucunda birçok fiziksel ve fizyolojik özellik arasında anlamlı ilişki katsayıları bulunmuştur. Sonuç olarak; sporcuların vücut ağırlıkları, vücut yağ yüzdeleri, boy uzunlukları ve sırt kuvvetlerinin anaerobik performanslarında belirleyici rol aldığı tespit edilmiştir

Protective effect of insulin and glucose at different concentrations on penicillin-induced astrocyte death on the primer astroglial cell line

Astrocytes perform many functions in the brain and spinal cord. Glucose metabolism is important for astroglial cells and astrocytes are the only cells with insulin receptors in the brain. The common antibiotic penicillin is also a chemical agent that causes degenerative effect on neuronal cell. The aim of this study is to show the effect of insulin and glucose at different concentrations on the astrocyte death induced by penicillin on primer astroglial cell line. It is well known that intracranial penicillin treatment causes neuronal cell death and it is used for experimental epilepsy model commonly. Previous studies showed that insulin and glucose might protect neuronal cell in case of proper concentrations. But, the present study is about the effect of insulin and glucose against astrocyte death induced by penicillin. For this purpose, newborn rat brain was extracted and then mechanically dissociated to astroglial cell suspension and finally grown in culture medium. Clutters were maintained for 2 weeks prior to being used in these experiments. Different concentrations of insulin (0, 1, 3 nM) and glucose (0, 3, 30 mM) were used in media without penicillin and with 2 500 μM penicillin. Penicillin decreased the viability of astroglial cell seriously. The highest cell viability appeared in medium with 3 nM insulin and 3 mM glucose but without penicillin. However, in medium with penicillin, the best cell survival was in medium with 1 nM insulin but without glucose. We concluded that insulin and glucose show protective effects on the damage induced by penicillin to primer astroglial cell line. Interestingly, cell survival depends on concentrations of insulin and glucose strongly. The results of this study will help to explain cerebrovascular pathologies parallel to insulin and glucose conditions of patient after intracranial injuries. © 2012, Editorial Board of Neural Regeneration Research. All rights reserved

A new index for the prediction of in-hospital mortality in patients with acute pulmonary embolism: The modified shock index

BACKGROUND: Pulmonary embolism severity index, its simplified version, and shock index have been used for risk stratification in acute pulmonary embolism. In this study, we proposed a modification in severity index and evaluated the correlates and prognostic value of modification in severity index in this setting. METHODS: The study group comprised retrospectively evaluated 181 patients with acute pulmonary embolism. Systematic workup including pulmonary embolism severity index, its simplified version, shock index, biomarkers, and echocardiographic and multidetector computed tomography assessments was performed in all patients. Moreover, we calculated modification in severity index by multiplying original shock index (heart rate/systolic blood pressure ratio) and a third component, 1/pulse oxymetric saturation (pSat O2%) ratio. The primary endpoint was defined as all-cause mortality and hemodynamic collapse during the hospital stay. RESULTS: On the basis of initial risk stratification, ultrasound-assisted thrombolysis, systemic tissue-type plasminogen activator, and unfractionated heparin therapies were utilized in 83 (45.9%), 37 (20.4%), and 61 (33.7%) patients, respectively. The primary end-point occurred in 13 (7.2%) patients. Receiver-operating curve analysis revealed that modification in severity index had the highest area under the curve of 0.739 (0.588-0.890, P =.002) compared with shock index, pulmonary embolism severity index, or its simplified version. The modification in severity index > 0.989 predicted primary endpoint with 73% sensitivity and 54% specificity. CONCLUSIONS: The modification in severity index seems to be a simple, quick, and compre-hensive risk assessment tool for bedside evaluation at initial stratification, in monitoring the clinical benefit from therapies, and decision-making for escalation to other reperfusion strategies in patients with acute pulmonary embolism. However, the prognostic value of modification in severity index needs to be validated with further studies