71 research outputs found
Recommended from our members
Developing a passive house with a double-skin envelope based on energy and airflow performance
This research originated from an interest in developing products with a holistic and interdisciplinary systems engineering approach, toward fostering sustainability. A comprehensive method which helps designers make better decisions in the earliest design stage was applied for conceptual model development and comparison. The study developed a new-design passive house with a double-skin envelope that delivers better energy consumption performance for heating and cooling relative to a conventional reference house, while achieving comfort-level indoor temperatures. A single-façade reference house was designed with the identical geometry, material and conditions of the new house living quarters, in order to demonstrate the new house performance using a valid comparison. The new house and reference house were simulated cases and were not calibrated by actual models. The energy simulations demonstrated that the heating and cooling demands of the new house were 19.1% and 18.8% lower than those of the reference house, respectively. Furthermore, fluid dynamics behavior of the air inside the double-skin envelope was analyzed to demonstrate the airflow’s contribution to the energy performance. Computational fluid dynamics simulations revealed that turbulent airflow in the underground space on summer day increased heat transfer, and laminar airflow in the double-skin roof on winter night decreased such transfer
Histopathological distribution of thyroid cancers: A retrospective analysis of 570 patients
Aim: Thyroid cancers are the most commonly encountered endocrine system malignancies. The incidence continues to rise worldwide. Our aim in this study is to investigate the frequency and histopathological subtypes of thyroid cancer in our clinic.
Methods: The present study was conducted with 3614 patients who were followed up in our endocrinology and general surgery clinic and operated with the diagnosis of multinodular and/or nodular goiter between 2015 and 2021. The histopathological types and information of patients diagnosed with thyroid cancer were obtained retrospectively from the pathology reports. Among the patients included in the study, a total of 570 people who were reported to have thyroid cancer due to histopathology were included in the study.
Results: The data of a total of 3614 biopsy reports were examined for the study. Among these patients, 570 (421 females, 149 males) were operated and whose pathology reports were accessed were included in the study. The mean age of the patients was 49.12±10.4 years. As a result of the operations, malign postoperative tissue histopathology was 98.9% (n=564), and uncertain malignancy potential was reported to be 1.0% (n=6). In our study, the histopathological distribution of thyroid cancers was as follows; thyroid papillary cancer 89.4% (n=510), follicular cancer 7.3% (n=42), medullary cancer 2.1% (n=12), and malignancy potential uncertain 1.0% (n=6).
Conclusion: The results of our study suggest that thyroid cancers are more common in women in our country, in parallel with the similar rates reported in the literature, with the increase worldwide
REMINERALIZATION OF PRIMARY MOLAR DENTINE WITH SILVER DIAMINE FLUORIDE AND SODIUM FLUORIDE : AN IN VITRO STUDY
ABSTRACT
Objectives: Silver diamine fluoride (SDF) offers a minimally invasive and inexpensive alternative to traditional restorative caries treatment. Aim of this study was to evaluate the mineral density value and remineralization effect of 38% SDF solution and 5% sodium fluoride (NaF) varnish on artificial primary tooth dentin caries lesions.
Materials and Methods: 54 extracted sound primary molars were demineralized and allocated into two groups: SDF and NaF groups. After pH-cycling, mineral density values (MDV) were assessed with micro computed tomography (micro-CT) and surface morphology were studied via scanning electron microscopy (SEM).
Results: After remineralization agents were apllied and specimens pH-cycled, the MDVs of the Region of Interest (ROI) in lesions increased in both NaF and SDF group. The mean MDV of SDF applied specimens was found to be higher than NaF applied specimens at statistically significant level. In the SEM images, it was observed that the dentinal tubules orifices were occluded almost completely in SDF group while the orifices in NaF group were partially occluded.
Conclusions: The use of 38% SDF demonstrated a great remineralization effect on primary molar dentin than 5% NaF varnish. Further clinical studies are needed to investigate the effect of 38% SDF on primary molars which remains in the mouth longer than incisors and have a great function on chewing
4-[2-(Cyclohexa-1,4-dien-1-yl)ethoxy]benzene-1,2-dicarbonitrile
In the title compound, C16H14N2O, the dihedral angle between the aromatic rings is 70.23 (6)°. The linking chain has a zigzag conformation. In the crystal, molecules are linked by weak intermolecular C—H⋯N hydrogen bonds, forming a zigzag chain along the c axis
Impact of the COVID-19 pandemic on diabetic ketoacidosis management in the pediatric intensive care unit
Background Diabetic ketoacidosis (DKA) is a common endocrine emergency in pediatric patients. Early presentation to health facilities, diagnosis, and good management in the pediatric intensive care unit (PICU) are crucial for better outcomes in children with DKA. Methods This was a single-center, retrospective cohort study conducted between February 2015 and January 2022. Patients with DKA were divided into two groups according to pandemic status and diabetes diagnosis. Results The study enrolled 59 patients, and their mean age was 11±5 years. Forty (68%) had newly diagnosed type 1 diabetes mellitus (T1DM), and 61% received follow-up in the pre-pandemic period. Blood glucose, blood ketone, potassium, phosphorus, and creatinine levels were significantly higher in the new-onset T1DM group compared with the previously diagnosed group (P=0.01, P=0.02, P<0.001, P=0.01, and P=0.08, respectively). In patients with newly diagnosed T1DM, length of PICU stays were longer than in those with previously diagnosed T1DM (28.5±8.9 vs. 17.3±6.7 hours, p<0.001). The pandemic group was compared with pre-pandemic group, there was a statistically significant difference in laboratory parameters of pH, HCO3, and lactate and also Pediatric Risk of Mortality (PRISM) III score. All patients survived, and there were no neurologic sequelae. Conclusion Patients admitted during the pandemic period were admitted with more severe DKA and had higher PRISM III scores. During the pandemic period, there was an increase in the incidence of DKA in the participating center compared to that before the pandemic
Probabilistic seismic hazard assessment of Eastern Marmara Region
The objective of this study is to evaluate the seismic hazard in Eastern Marmara Region using an improved probabilistic seismic hazard assessment methodology. Two significant improvements over the previous seismic hazard assessment practices are accomplished in this study: advanced seismic source characterization models in terms of source geometry and recurrence relationships are developed, and improved global ground motion models (NGA-W1 models) are employed to represent the ground motion variability. Planar fault segments are defined and a composite magnitude distribution model is used for all seismic sources in the region to properly represent the characteristic behavior of the North Anatolian Fault without the need for an additional background zone. Multi-segment ruptures are considered using the rupture model proposed by the Working Group on California Earthquake Probabilities (2003). Events in the earthquake catalogue are attributed to the fault zones and scenario weights are determined by releasing the accumulated seismic energy. The uniform hazard spectra at 10 % probability of exceedance in 50 years hazard level for different soil conditions (soil and rock) are revealed for specific locations in the region (AdapazarA +/-, Duzce, Gemlik, Izmit, Iznik and Sapanca). Hazard maps of the region for rock site conditions at the selected hazard levels are provided to allow the readers perform site-specific hazard assessment and develop site-specific design spectrum for local site conditions
The Appraisal of The Historic Interventions to the Superstructure Through Time: The Case of Reinforced Concrete
Amasya Bimarhanesi’nin tamamlanamayan taçkapısı
Amasya Bimarhanesi’nin taçkapısının 1950’lerdeki onarımının, Türkiye’deki koruma yaklaşımları bağlamında ayrı bir önemi vardır. Onarımda taçkapının eksik kısmı tamamıyla bütünlenmemiştir. Bunun yerine yalnız bir köşesinden duvar kademeli olarak yükseltilmiştir. Onarımın yapıldığı tarihlerde henüz 7044 sayılı yasa yoktur ve Amasya Bimarhanesi’nin sorumluluğu Vakıflar Genel Müdürlüğü’nde (VGM) de değil; Maarif Vekâleti Eski Eserler ve Müzeler Genel Müdürlüğü’ne (EEMGM) aittir (2). Bu tarihlerde müdürlüğün Abideler Şubesi’nde Yüksek Mimar Ali Saim Ülgen görev yapmaktadır. Ülgen tarafından yürütülen bu uygulama, Amasya Bimarhanesi’ne özgü olup; başka bir yapıda gerçekleştirilmemiştir (Resim 1). Başka örneği olmayan bu tamamlama şekli sadece dönemi bağlamında değil, günümüz için de geçerli olan modern bir koruma yorumu taşıdığından kendinden birçok defa bahsettirmiştir. Cevat Erder, 1967 tarihli bir çalışmasının başında Amasya Bimarhanesi’nin fotoğrafını “Ali Saim Ülgen tarafından yapılan ilginç bir restorasyon” notunu yazarak paylaşmıştır (Erder, 1967, 53) (3). Ömür Bakırer 1985 yılında yayımlanan tamamlama tekniği ile ilgili çalışmasında Bimarhane’nin taçkapı onarımına değinmiştir. Bimarhane’deki tamamlamanın “çerçevenin üst kısmında, yatay yönde uzanan bordürlerin basamaklı kesilen düzeni” ile diğer örneklerden farklı olduğunu ve bu tamamlama şeklinin yalnız Amasya Bimarhanesi’nde gerçekleştirildiğini söylemiştir (Bakırer, 1985, 52). Benzer bir değerlendirmeyi Can Hersek de yapmıştır: “tamamlayıcı bir restorasyon yerine yalnızca kapının eski boyutunu hissettirecek ölçüde bir onarım yapılmış olup, yeniden yapılan kısımlarda kenar bordürlerinin süslemeleri de işlenmemiştir” (Hersek, 1993, 321). Ali Saim Ülgen’in kişisel arşivinden elde edilen bazı belgeler, bu müdahaleyle ilgili yeni bilgileri ortaya çıkarmaktadır (4). Belgelerden onarım sürecinde işveren ve yüklenici arasında karşılıklı memnuniyetsizlikler olduğu, onarımda planlanan birçok iş kaleminin yapılamadığı veyahut yarım kaldığı öğrenilmektedir. Ülgen’in keşif için hazırladığı hem hesaplamalar hem de eskizler, taçkapının konu edilen tamamlama şeklinden farklı olarak - diğer örneklerde olduğu gibi - bütünlemek istenildiğini göstermektedir (Resim 2). Hatta Ülgen, taş onarımlarında bezemelerin bile yeniden yapılmasını hedeflemiştir. Ancak yine de onarım süreci tam olarak aydınlatılamamaktadır. Taçkapının bir ucundan yükselen kademeli tamamlama kararı nasıl verilmiştir? Taçkapının tamamlanması için yapıdan gelen veriler yeterli olmadığı için bir deneme olarak mı işe başlanılmıştır? Eğer bir deneme ise hatalı yapıldığı için mi iş durdurulmuştur? Veyahut tamamlama işi doğru yapılıyorken yüklenici ile yaşanan ciddi sorunlardan dolayı mı iş yarım bırakılmıştır? Ya da işler sarpa sarınca, yapılan iş olduğu gibi kabul edilip yıllarca bu şekilde kalmasına izin mi verilmiştir? Doğru soruyu ve cevabını bulmadan önce 20. yüzyılda gerçekleşen bu onarımı daha iyi değerlendirebilmek için yapının mimari özellikleri ve onarım tarihinin bilinmesi gereklidir.Publisher's Versio
- …