Transcanalicular multidiode laser versus external dacryocystorhinostomy in the treatment of acquired nasolacrimal duct obstruction

Objectives: This study was a comparison of the outcomes of transcanalicular multidiode laser dacryocystorhinostomy (TCLDCR) and external dacryocystorhinostomy (EXDCR) treatment for patients with acquired nasolacrimal duct obstruction. Methods: Thirty-one consecutive patients who underwent TCLDCR (TCLDCR group) and 68 consecutive patients who underwent EXDCR (EXDCR group) due to acquired nasolacrimal duct obstruction were enrolled in the study. Follow-up visits were performed on the first day, and at the first week, first month, third month, sixth month, and every six months thereafter. Surgical success was defined as achievement of a patent osteotomy and a successful bicanalicular silicone intubation during the procedure. Anatomical success was defined by observation of a patent osteotomy on lacrimal irrigation, regardless of epiphora. The surgery time and intra- and postoperative complications were noted for each patient. Results: The TCLDCR group had a significantly shorter mean surgery time (27.9±5.5 minutes) compared with the EXDCR group (58.5±12.0 minutes) (p<0.001). However, the mean anatomical and functional rates of TCLDCR (58.0% and 54.8%, respectively) were significantly lower than those of the EXDCR group (94.1% and 91.1%, respectively) (both p<0.001). Two patients had "cheese wiring" damage of the lower canaliculus and 1 patient in the TCLDCR group had a full-thickness skin defect in the medial canthal region. No serious intra- or postoperative complication occurred in the EXDCR group. Conclusion: Although a TCLDCR procedure decreased the surgical time, it had a significantly lower success rate in the treatment of acquired nasolacrimal duct obstruction compared to EXDCR. The decision of the type of surgery should be made based on the cosmetic and success expectations of the patients and the presence of systemic problems

Yarım Düzlem Üzerine Oturan Elastik Tabakanın Sürtünmesiz Ve Ayrılmalı Temas Problemi

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2015Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2015Bu çalışmada, yarım düzlem üzerine oturan ve rijit iki dikdörtgen blok aracılığıyla yüklenmiş bir tabakanın simetrik ayrılmalı temas problemi elastisite teorisine göre incelenmiştir. Temas eden tüm yüzeyler sürtünmesiz olup, kütle kuvvetlerinin etkisi ihmal edilmiştir. Problem integral dönüşüm teknikleri ve sınır şartları kullanılarak temas gerilmelerinin bilinmeyen fonksiyonlar olduğu bir integral denklem sistemine indirgenmiştir. Uygun Gauss-Jacobi integrasyon formülleri yardımıyla integral denklem sistemi sayısal olarak çözülmüştür. Temas gerilmeleri ve temas uzunluklarına ait sayısal sonuçlar çeşitli boyutsuz büyüklükler için belirlenmiştir.In this study, symmetric receding contact problem for an elastic layer resting on an elastic half plane loaded by means of two rectangular rigid stamps is considered according to theory of elasticity. The problem is solved under the assumptions that all surfaces are frictionlesss, the effect of gravity forces is neglected. The problem is reduced a system of integral equation in which the contact pressures are unknown functions by using the integral transform tecnique and boundary conditions of the problem. The system of singular integral equation is solved numerically by making use of appropriate Gauss-Jacobi integration formulas. Numerical results for the contact pressures and contact areas are investigated for various dimensionless quantities

Utjecaj toplinske obrade drva divlje trešnje na otpornost na habanje i čvrstoću držanja vijaka

In its wise use, many properties of wood are important. Among these properties, wood abrasion resistance (AR) and withdrawal capacity of screws (WCS) are deemed to be relatively signifi cant. It is well know that heat treatment changes the resistance features of wooden materials by changing the structural characteristics of wood. Within the scope of this study, the effects were investigated of the temperature and duration of heat treatment of Wild Cherry (Cerasus avium (L.) Monench) on its AR and its WCS in the radial direction and tangential direction. The test results indicated that weight loss (WL) and thickness reduction (TR) remained almost the same in the radial direction specimen, but there was significant TR in the tangential direction specimen. As a result of these changes, the abrasion effect of the S-42 abrader diminished based on the increase in the number of cycles. However, in both the radial and tangential direction, the WCS decreased to a significantly greater extent in the heat-treated specimens than in the control specimens.Za brojne uporabe drva bitna su mnoga njegova svojstva, a među važnijima su otpornost na habanje (AR) i čvrstoća držanja vijaka (WCS). Dobro je poznato da toplinska obrada drva zbog promjene obilježja građe drva mijenja njegova svojstva otpornosti. U sklopu ovog rada istraživani su učinci temperature i trajanja toplinske obrade drva divlje trešnje (Cerasus avium (L.) Monench) na njegovu otpornost na habanje i čvrstoću držanja vijaka u radijalnome i tangencijalnom smjeru. Rezultati istraživanja pokazali su da se gubitak mase (WL) i smanjenje debljine (TR) uzoraka ne pojavljuju u radijalnom smjeru, ali je značajno smanjenje debljine zabilježeno u tangencijalnim uzorcima. Kao rezultat tih promjena, učinak abrazije primjenom S-42 abraziva smanjuje se s povećanjem broja ciklusa. Međutim, i u radijalnome i u tangencijalnom smjeru znatno se smanjuje čvrstoća držanja vijaka toplinski obrađenih uzoraka u usporedbi s kontrolnim uzorcima

THE ANALYSIS OF RELATION BETWEEN DIFFERENT VARIABLES AND UNIVERSITY STUDENTS’ MOTIVES FOR PARTICIPATION IN SPORTS

The object of this study is to determine the motives of university students who participate in physical activities during college education and examine whether the data differ according to educational background, sex and family support. A total of 100 students from the department of physical education and sports teaching participated in the study. As a data collection tool in the work, "Participation in Sport Motivation Scale", Gill et al. (1983), translated into Turkish by Çelebi (1991) and published by Oyar et al. (2001) have been used for validity and reliability between the studies in the age of 11-17 (6,13). In the study, reliability was checked again for this group and reliability coefficient was 0.86 in Cronbach Alpha internal consistency test. The most important motive for participation in sports for university students in the study has been found to be "skill development" and "movement/activity". In the consequences related with the motives of individuals for participation in sports, because the average for each sub-dimension is high, differences within these averages can be a determining factor in the preparation of the activities, plans and programs to be carried out and more and willing participation of the individuals in their physical activity.  Article visualizations

CNC İşleme Merkezlerinde Hataların İş Esaslı Yaklaşımla Düzeltilmesi

Bu çalışmada, endüstri 4.0 uygulamalarında öne çıkan sıfır hata konseptine göre işparçasının işlenmesi sırasında düşük maliyetli kompanzasyon (telafi) metodu geliştirilmiştir. Yeni yöntem sayesinde, delik delme esnasında oluşan eksen hataları tespit edilmiş ve referans mastar blokları yardımıyla doğrulama faktörü bulunmuştur. Bu faktör kullanılarak, hata miktarı oranında nümerik kontrol (NC) kodları güncellenmiştir. Elde edilen sonuçlara göre, makine üzerine takılı ölçme probu yardımıyla doğru ve izlenebilir ölçüm yapılabildiği sonucuna ulaşılmıştır. Bu yöntemin düşük bir maliyet ile hassas parça imalatında kullanılabilir olduğu sonucuna varılmıştır. Delik mesafesi 500 mm için 55 μm olan tezgâhtan kaynaklanan eksen hatasının, yeni yöntemle ± 10 µm tolerans aralığında gerçekleştiği tespit edilmiştir. Kompanzasyon yöntemi yardımıyla eksen sapma değerleri %81 oranında iyileştirilmiştir

Research for University Students’ Levels of Dealing with Stress from Different Types of Variables

This research aims to investigate university students’ levels of dealing with stress, from different types of variables. The study was carried out on a total of 500 individuals, including 346 female and 154 male students studying at Atatürk University Kazim Karabekir Faculty of Education in 2016/2017 academic year. In this work, Oral, Çok ve Kutlu (2005) "The Level of dealing with Stress in Educational System" scale was for the students. SPSS 21 package program was used in the analysis of the data. For the analysis of the data, and in determining the demographics, the frequency distribution was used. T test was applied to examine the relationship between two independent variables and stress coping sub-dimensions and Anova Warians analysis tests were used to examine the relationship between two and over variables and stress subscale sub-dimensions. The difference between the variables has been interpreted on the basis of p0.05 significance level. According to the findings, it was found that, there is a significant difference between individuals' stress coping sub-dimensions and gender, book reading habits and spare time activity. There was no significant difference between age, family structure and monthly income variables.It was found out that the scores of female students were higher than the average scores of male students with regard to studying from students' gender and stress coping levels subscales, preparing for an exam and affective, behavioral sub-dimensions. The students who stated that they had the habit of reading books, were found to have high scores in studying, preparing for an exam and the affective behavioral sub-dimensions. It was deduced that the students who spent their leisure time with their family got higher scores from students who spent their spare times with their friends or alone, with regard to studying, preparing for an exam and the affective behavioral sub-dimensions.In order to make students, more effective and successful in educational system, the factors that affect the stress levels should be determined and similar studies are necessary in order to have positive effects for students, which, constitutes the part of the proposal of our study. Keywords: University student, Stress, Dealing with stres

Investigation of the effect of using ultrasonic fuel system on exhaust emissions in a spark ignition engine

Buji ateşlemeli motorlarda kullanılan yakıtın parçalanıp hava ile karıştırılması, yanma ve egzoz emisyonu üzerinde oldukça etkilidir. Motorun farklı çalışma koşullarına uygun ideal hava-yakıt karışım oranını hazırlamak için yakıt sistemleri üzerinde çalışılmalar yapılmaktadır. Bu çalışmada buji ateşlemeli motorlarda kullanılan geleneksel yakıt sistemlerine alternatif olarak ultrasonik yakıt sistemi kullanılmıştır. Buji ateşlemeli motorlarda kullanılan enjektörlü yakıt sisteminde 20-30 µm olan ortalama damlacık çapı, ultrasonik parçalama ile ortalama damlacık çapı 12 µm olarak gerçekleşmiştir. Motor ½ sabit yükte farklı devirlerde ultrasonik, karbüratörlü ve enjeksiyonlu yakıt sistemleri ile çalıştırılıp egzoz emisyonları ölçülmüştür. Üç yakıt sistemi için ölçülen egzoz emisyonlarının maksimum değerleri karşılaştırmalı olarak incelenmiştir. Ultrasonik yakıt sistemi kullanıldığında, karbüratörlü sisteme göre CO da %99, HC de %60, NOx de %18 azalma, CO2 de % 10 ve artış olduğu, enjektörlü sisteme göre CO da %99, CO2 de %12, HC de %45 azalma, NOx de % 55 artış olduğu görülmüştür. Genel olarak ultrasonik yakıt sisteminin egzoz emisyonları üzerinde olumlu etkisinin olduğu belirlenmiştir.Fragmentation and mixing of the fuel used in spark ignition engines with air is highly effective on combustion and exhaust emissions. Studies are carried out on fuel systems in order to prepare the ideal air-fuel mixture ratio suitable for different operating conditions of the engine. In this study, ultrasonic fuel system was used as an alternative to the traditional fuel systems used in spark ignition engines. The average droplet diameter of 20-30 µm in the injector fuel system used in spark ignition engines has been realized as 12 µm with ultrasonic fragmentation. The engine was run at ½ constant load at different speeds with ultrasonic, carburetor and injection fuel systems, and exhaust emissions were measured. The maximum values of the measured exhaust emissions for the three fuel systems were examined comparatively. When the ultrasonic fuel system is used, there is a 99% reduction in CO, 60% in HC, 18% in NOx, 10% and an increase in CO2 compared to the carburetor system, 99% reduction in CO, 12% in CO2, and 45% in HC compared to the injector system. It was observed that there was a 55% increase in NOx. In general, it has been determined that the ultrasonic fuel system has a positive effect on exhaust emissions

Serum YKL-40 levels as a novel marker of inflammation and endothelial dysfunction in patients with pseudoexfoliation syndrome

WOS: 000321700800013PubMed: 23661157Purpose To evaluate serum levels of YKL-40 in patients with pseudoexfoliation syndrome (PEX) in comparison with those of age-and sex-matched healthy subjects. Methods Forty patients with PEX (PEX group) and 40 age- and sex-matched control subjects (control group) were enrolled in the study. An enzyme immunoassay method using the commercially available test MicroVue YKL-40 was used to measure serum YKL-40 concentration. Systolic and diastolic blood pressures, serum levels of high sensitivity C-reactive protein (hsCRP), total cholesterol, low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), and triglycerides were also examined. Results the mean age was 54.4 +/- 7.6 (ranging 41-65) years in each group. the mean serum YKL-40 level of the PEX group was significantly higher than that of the control group (P<0.001). in addition, the mean serum HsCRP, total cholesterol, LDL, and triglycerides levels were significantly higher, and mean serum HDL level was significantly lower in the PEX group than in the control group (all P<0.001, excluding both P = 0.002 for triglycerides and HDL levels). Further, the mean systolic and diastolic blood pressures were significantly higher in the PEX group than in the control group (P-1 = 0.001 and P-2 = 0.01, respectively). Conclusion We have shown a relationship between PEX and elevated serum levels of YKL-40. We imply that a better understanding of the role of YKL-40 in the pathogenesis of endothelial dysfunction and atherosclerosis is necessary to develop new therapies for preventing or treating PEX. Further studies are warranted to clarify the clinical relevance of these findings

A scrutiny study on wave energy potential and policy in Turkey

Recently new and renewable energy sources began to become prominent as alternatives to fossil fuels. Among these are wind, solar, hydraulic, biomass, geothermal and wave energies. As for Turkey, the least accounted and less applied of these sources is wave energy. The government has established a short-term outlook on utilization of renewable energy sources, named “National Renewable Energy Action Plan” which is a part of Vision 2023 targets. Nonetheless, there is no planned utilization of and/or investment into wave energy in Turkey’s agenda up to the year 2023. This might be mainly because of the complex structure of wave energy conversion systems, marine conditions, mechanical difficulties and high initial investment costs. However, this type of energy is environmentally friendly, cheap and clean, and a great potential is available especially in Turkey which is surrounded on three sides by sea. Although Turkey has neither coasts to oceans nor a long stretch of west coastline, which have the highest energetic waves thanks to the prevailing west-to-east winds; the Black Sea basin, as well as the south-western Mediterranean region, may offer a good potential for development as an energetic regime, often comparable to oceanic sites in terms of wave heights, induced by strong wind patterns. In this study, wave energy potential in Turkey and recent studies made on determination of suitable sites for evaluation of wave energy in Turkey are discussed

Operational stability and degradation of organic solar cells

Recently, Organic solar cells (OSC) have been increasingly utilized all over the world. The changes made in the organic components of the organic solar cells enable them to exhibit good features such as mechanical flexibility, lightness and high power generation efficiency even under lower light intensities. However, operational stability is an important parameter for organic solar cells. Despite the aforementioned advantages of organic solar cells, degradation in operational environments limits their use in harsh conditions. Studies have shown that the organic layer and the cathode layer of the OSCs are degraded by external factors, and this adversely affects the operational stability and productivity of OSCs considerably. The overall efficiency of an organic solar cell is defined as a function of life cycle and efficiency of energy generation. Therefore, the shorter the life cycle becomes, the lesser the overall efficiency of OSCs gets. Recent studies are focused on improving the operational stability and power generation efficiencies of OSCs by reducing the effects degradation induced by external factors, such as climatic conditions and thermal fatigue. The purpose of this study is to assess how organic solar cells work, how they degrade from external factors, such as water and water vapor, and how these parameters affect the operational stability as well as the efficiency of the organic solar cells