Yeni Nesil İnce Filmler İle Optoelektronik Uygulamaların Araştırılması

The aim of this study is to develop easy to fabricate and inexpensive ultraviolet photodetectors with metal oxide thinfilms and to improve or change the performance of those devices using designed nanostructures. For this purpose Titanium Dioxide (TiO2) and Zinc Oxide (ZnO) materials were selected which are used for ultraviolet photodetector fabrication. As the deposition method for those materials one of the physical deposition methods, RF Magnetron Sputtering was selected, which is easy to utilize and rather inexpensive in terms of operation. During the early stages of the study, TiO2 thin film deposition and device fabrication optimization studies were performed. The properties of the annealed and Oxygen plasma treated thin films were investigated, the performances of the photodetectors fabricated using treated and untreated thin films were compared and found out that the photodetectors fabricated using untreated thinfilms were performing comparably with the photodetectors fabricated with treated thinfilms. The photodetectors fabricated with untreated thin films showed breakdown voltages larger than 50 V, dark curent density less than 2.1x10-8 A/cm2, 1.8 A/W responsivity, %1750 internal quantum efficiency and 9 s and 3.5 s rise and fall times respectively. Although these results are similar with the results ontained from treated thin films given in the literature, they are interesting because the photodetectors were fabricated by simple and cheap processes without any post annealing or plasma treatment. The next stage of the study was to design nanoplasmonic structures on those well performing photodetectors to improve or modify the spectral response of the photodetector for specific applications. Integrating the designed nanoplasmonic structure with the photodetetor the response of the photodetector in UVB bant was reduced by 60%. This was a demonstration of the usage of nanoplasmonic structures (which are mostly used in IR bant) for the modification of spectral response of the photodetectors for specific applications and the first usage of nanoplasmonic filters in UV bant. During the following stages of the study, photodetectors were fabricated using as deposited ZnO thin films with breakdown voltage of larger than 100 V, dark current densities as low as 100 pA/cm2 at 100 V bias voltage, respective rise and fall times of as low as 22 ps and 8 ns and responsivity of 0.35 A/W were obtained. Another phase of the ZnO thin film photodetector study was investigating the optoelectronic properties of Ge nanoparticle doped ZnO thin films and developing devices using this material. The characterization of the deposited thin films were done and photoconductor, Si heterojunction and TiO2 heterojunction devices as the first concept in literature were fabricated and characterized.Tez çalışmamda temel olarak metal oksit ince film malzemeler kullanılarak üretimi kolay ve ucuz morötesi fotodedektörler geliştirilmesi ve bu aygıtlar üzerine işlenen nano yapılar ile aygıt performansının kontrollü iyileştirilmesi amaçlanmıştır. Bu amaçla çalışmamda, literatürde morötesi fotodedektör aygıtları yapımında kullanılan Titanyum Dioksit (TiO2) ve Çinko Oksit (ZnO) malzemeleri seçilmiştir. Bu malzemelerin üretimi için kolay ve ucuz bir yöntem olması açısından fiziksel kaplama metodu olarak saçtırma yöntemi kullanılması tercih edilmiş ve üretimi kolay ve ucuz olacak aygıt tipleri ve üretim teknikleri kullanılmıştır. Çalışmanın ilk safhasında TiO2 ince filmlerin üretimi ve aygıt üretim sürecinin optimizasyonu yapılmıştır. Isıl işleme veya Oksijen plazmasına tabi tutulmuş ince filmlerin özellikleri incelenmiş ve bu ince filmler ile üretilen fotodedektörlerin performansları karşılaştırılmıştır. Isıl veya plazma işlemlerine tabi tutulmuş ince filmler ile üretilen fotodedektörlerin performansının hiç işlem görmemiş fotodedektörlere göre belirgin bir fark göstermediği sonucuna varılmıştır. 50 V'dan yüksek kırılma gerilimleri, 2.1x10-8 A/cm2 gibi oldukça düşük bir karanlık akım yoğunluğu, 1.8 A/W gibi yüksek bir fotocevap, %1750 mertebesinde iç kuvantum verimi ve 9 s yükselme, 3.5 s düşme zamanları elde edilmiştir. Bu sonuçlar literatür ile karşılaştırıldığında ısıl veya plazma işlemlerine tabi tutulmuş aygıtlar ile aynı seviyede değerler olmasına karşın ince filme büyütme sonrası herhangi bir işlem yapılmaksızın üretilebildiği için üstünlük sağlayan sonuçlardır. Çalışmanın ilerleyen aşamalarında bu yüksek performanslı, kolay ve ucuz üretim yöntemleri ile üretilmiş fotodedektörler üzerine nanoplazmonik yapılar tasarlanmış ve bu fotodedektörlerin izgesel cevabının uygulamaların ihtiyacına göre değiştirilebileceği gösterilmiştir. Nanoplazmonik yapıların fotodedektör ile entegre edilmesi ile fotodedektörün UVB bandındaki fotocevabı %60 mertebesinde düşürülerek morötesi fotodedektörlerde izgesel fotocevabın nanoplazmonik yapılar ile izgesel cevaplarının soğurma bölgesi içerisinde uygulama ihtiyacına göre modifiye edilebileceği, daha çok yakın kızılötesi ve görünür dalgaboylarında uygulanan nano plazmonik filtrelerin morötesi bölgesinde de uygulanabileceği gösterilmiştir. Kaplandığı hali ile ZnO ince filmler ile de benzer şekilde fotodedektörler üretilmiştir. Bu aygıtlar ile yine 100 V'tan büyük kırılma gerilimine sahip ve 100V'ta 100 pA/cm2 gibi literatürdeki değerlere göre çok düşük karanlık akım yoğunlukları ölçülmüştür. 22 ps yükselme ve 8 ns düşme zamanları ile çok yüksek hızlarda çalışabilen, 0.35 A/W gibi kabul edilebilir seviyede fotocevap verebilen bir morötesi fotodedektör üretilmiştir. Bir diğer çalışma ise ZnO ince filmlerin üretimi sırasında Ge nanoparçacıklarının katkılanması ile elde edilen ince filmlerin optik ve elektro-optik özelliklerinin değişiminin incelenmesidir. Üretilen ince filmlerin karakterizasyonlarının yanısıra bu ince filmler ile fotoiletken, Silisyum ile heteroeklemli ve literatürde örneği görülmeyen, TiO2 ince filmler ile heteroeklemli aygıtlar üretilerek bu aygıtların optoelektronik özellikleri incelenmiştir

Healthcare personnel’s attitude and coverage about tetanus vaccination in Turkey: a multicenter study

The tetanus vaccine is not routinely given to Turkish adults. Protective tetanus immunity decreases with age. Health-care personnel (HCPs), who are role models in the field of health, are a target group in order to achieve a higher rate of tetanus vaccination in the community. This study was designed to evaluate attitudes and coverage regarding tetanus vaccination among a large sample of Turkish HCPs. This cross-sectional epidemiologic study was conducted from July to August 2019. A questionnaire was sent to HCPs using social media. Of the 10,644 HCPs included in the study, 65% were female. Overall, the tetanus vaccination coverage (TVC) among HCPs was 78.5% (95% CI: 77.7%-79.3%). TVC was significantly higher among physicians [83.4% (95% CI: 82%-84.6%); p < .001] compared with all other HCPs except nurses. Older age (≥40 years) and length of professional experience were significantly correlated with TVC. Of the 8353 HCPs who received tetanus vaccines during their lifetime, 73.03% received tetanus vaccination in the past 10 years. The self-vaccination rate for protection against tetanus was 13.1%. Acute injuries (25.42%) and pregnancy (23.9%) were the most common reasons for having the tetanus vaccine. One-third (33.7%) of HCPs did not have information about whether pregnant women could receive tetanus vaccinations. This survey study provided excellent baseline information about HCPs’ coverage rates and attitudes regarding tetanus vaccination. The present results suggested that tetanus boosters for HCPs should be established as soon as possible, and revealed that the HCPs younger than 30 years with relatively less professional experience and all other HCPs except nurses and physicians should be identified as the target population for future intervention programs

Juvenile Myelomonocytic Leukemia in Turkey: A Retrospective Analysis of Sixty-five PatientsÖzlem Tüfekçi1

Objective: This study aimed to define the status of juvenile myelomonocytic leukemia (JMML) patients in Turkey in terms of time of diagnosis, clinical characteristics, mutational studies, clinical course, and treatment strategies. Materials and Methods: Data including clinical and laboratory characteristics and treatment strategies of JMML patients were collected retrospectively from pediatric hematology-oncology centers in Turkey. Results: Sixty-five children with JMML diagnosed between 2002 and 2016 in 18 institutions throughout Turkey were enrolled in the study. The median age at diagnosis was 17 months (min-max: 2-117 months). Splenomegaly was present in 92% of patients at the time of diagnosis. The median white blood cell, monocyte, and platelet counts were 32.9x109/L, 5.4x109/L, and 58.3x109/L, respectively. Monosomy 7 was present in 18% of patients. JMML mutational analysis was performed in 32 of 65 patients (49%) and PTPN11 was the most common mutation. Hematopoietic stem cell transplantation (HSCT) could only be performed in 28 patients (44%), the majority being after the year 2012. The most frequent reason for not performing HSCT was the inability to find a suitable donor. The median time from diagnosis to HSCT was 9 months (min-max: 2-63 months). The 5-year cumulative survival rate was 33% and median estimated survival time was 30+-17.4 months (95% CI: 0-64.1) for all patients. Survival time was significantly better in the HSCT group (log-rank p=0.019). Older age at diagnosis (&gt;2 years), platelet count of less than 40x109/L, and PTPN11 mutation were the factors significantly associated with shorter survival time. Conclusion: Although there has recently been improvement in terms of definitive diagnosis and HSCT in JMML patients, the overall results are not satisfactory and it is necessary to put more effort into this issue in Turkey

Kültürel Bellek 2016

Hacettepe Üniversitesi Tarihi ve Kültürel Mirası Araştırma Merkezi HÜTKAM olarak kültürel bellek çalışmalarına katkıda bulunmayı görevimiz kabul ediyoruz. 2016 yılında, yönetim kurulu olarak bu serüvene başlamaya karar verdik. Güvendiğimiz dostlarımız, arkadaşlarımız ve elbette hocalarımız çağrımızı yanıtsız bırakmadı. Birbirinden değerli araştırmalarla zenginleştik ve tarihe not düşmek adına kültürel bellek çalışmalarına biz de katıldık. Kültürel mirasın evrensel olduğu, oralı/buralı, sizden/bizden, uzak/yakın ayırmadan, hepimizin olduğu fikrinden yola çıktık. Bizi biz yapan, toplumları oluşturan, birleştiren kültürel belleğimizdir. Kimi zaman insan eliyle, cehaletle, yıkıcılıkla bazen adamsendecilikle, bilinçsizlikle tahrip edilen, yok edilen tarihi ve kültürel miras, belleğimizin önemli, çok önemli bir parçasıdır. Her zaman önünden geçtiğimiz bir yapı bir gecede yıkıldıysa, çocukluk anılarımızı biriktirdiğimiz mahallemiz yok olduysa, sokağımızın, meydanımızın adı değiştiyse eksiliriz. Bizi büyüten oyunlar kaybolduysa, bir tekerleme artık hatırlanmıyorsa, çocukluğumuzun sanatçıları göçmüşse, eski şarkılar plaklarda bile yoksa eksiliriz. Hafızamızı tetikleyen imgeler, kokular, sesler, tatlar değişirse bireysel belleğimiz, yaşadığımız kentin ve toplumun belleği zarar görür, eksiliriz. Bireysel tarihimizde, belleğimizdeki insanları yitirdikçe nasıl azalıyorsak tarihi ve kültürel mirası, ortak belleği yitirdikçe de öyle zayıflar ve giderek yok oluruz. İşte bu nedenle biz hatırlamayı, öğrenmeyi, görmeyi, araştırmayı seçiyoruz. Unutmamak için, unutulduysa hatırlamak ve hatırlatmak için, bilmeyenlere göstermek, anlatmak ve belleğimize sahip çıkmak için başladığımız bu serüvende çağrımızı kırmayan değerli araştırmacılara şükranlarımızı sunuyoruz. Unutmayalım ki kültürel bellek, hepimizi birleştiren güçtür

Evaluation of hepatitis serology and frequency of viral reactivation in patients with inflammatory arthritis receiving biologic agents: a multicenter observational study

To evaluate of hepatitis serology and reactivation frequency in patients with rheumatic disease receiving biologic agents. Our study included patients with inflammatory rheumatic diseases from 23 centers, who were followed up with biological therapy. Demographic and clinical characteristics of the patients, duration of drug use and hepatitis serology and the state of viral reactivation were analyzed. A total of 4060 patients, 2095 being males, were included in our study. Of the patients, 2463 had Ankylosing Spondylitis (AS), 1154 had Rheumatoid Arthritis (RA), 325 had Psoriatic Arthritis (PsA), and 118 had other inflammatory rheumatic diseases. When the viral serology of the patients was evaluated, 79 patients (2%) who were identified as HBs Ag positive, 486 (12%) patients who were HBs Ag negative and anti-HBc IgG positive and 20 patients (0.5%) who were anti-HCV positive. When evaluated on a disease-by-disease basis, the rate of HBsAg was found to be 2.5% in RA, 2% in AS and 0.9% in PsA. Viral reactivation was detected in 13 patients while receiving biologic agents. HBs Ag was positive in nine patients with reactivation and negative in four patients. Anti-HBc IgG, however, was positive. Six of these patients had AS, four had RA, and three had PsA. The development of hepatitis reactivation in 11.4% of HBs Ag positive patients and 0.82% of anti-HBc IgG positive patients due to the use of biologic agents is an important problem for this group of patients. Antiviral prophylaxis is recommended to be started especially in patients who are HBs Ag positive and who are using biologic agents due to viral reactivation. Therefore, it is important to carry out hepatitis screenings before biologic agent treatment and to carefully evaluate the vaccination and prophylaxis requirements

The Impact of CoronaVac Vaccination on 28-day Mortality Rate of Critically Ill Patients with COVID-19 in Türkiye

Background:Vaccines against coronavirus disease-19 (COVID-19) have been effective in preventing symptomatic diseases, hospitalizations, and intensive care unit (ICU) admissions. However, data regarding the effectiveness of COVID-19 vaccines in reducing mortality among critically ill patients with COVID-19 remains unclear.Aims:To determine the vaccination status and investigate the impact of the COVID-19 vaccine on the 28-day mortality in critically ill patients with COVID-19.Study Design:Multicenter prospective observational clinical study.Methods:This study was conducted in 60 hospitals with ICUs managing critically ill patients with COVID-19. Patients aged ≥ 18 years with confirmed COVID-19 who were admitted to the ICU were included. The present study had two phases. The first phase was designed as a one-day point prevalence study, and demographic and clinical findings were evaluated. In the second phase, the 28-day mortality was evaluated.Results:As of August 11, 2021, 921 patients were enrolled in the study. The mean age of the patients was 65.42 ± 16.74 years, and 48.6% (n = 448) were female. Among the critically ill patients with COVID-19, 52.6% (n = 484) were unvaccinated, 7.7% (n = 71) were incompletely vaccinated, and 39.8% (n = 366) were fully vaccinated. A subgroup analysis of 817 patients who were unvaccinated (n = 484) or who had received two doses of the CoronaVac vaccine (n = 333) was performed. The 28-day mortality rate was 56.8% (n = 275) and 57.4% (n = 191) in the unvaccinated and two-dose CoronaVac groups, respectively. The 28-day mortality was associated with age, hypertension, the number of comorbidities, type of respiratory support, and APACHE II and sequential organ failure assessment scores (p < 0.05). The odds ratio for the 28-day mortality among those who had received two doses of CoronaVac was 0.591 (95% confidence interval: 0.413-0.848) (p = 0.004).Conclusion:Vaccination with at least two doses of CoronaVac within six months significantly decreased mortality in vaccinated patients than in unvaccinated patients