Publications with Fulltext
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/6
Browse
363 results
Filters
Advanced Search
Filter by
Settings
Search Results
Publication Open Access Recommendations for clinical decision-making in children with type 1 diabetes and celiac disease: type 1 diabetes and celiac disease joint working group report(Galenos Yayınevi, 2022) Dalgıç, B.; Gökşen, D.; Aydoğdu, S.; Savaş, Erdeve Ş.; Kuloğu, Z.; Doğan, Y.; Aycan, Z.; Keser, A.; Beşer, Ö.F.; Özbek, M.N.; Bideci, A.; Ertem, D.; Evliyaoğlu, O.; Eliüz Tipici, B.; Gökçe, T.; Muradoğlu, S.; Koca, T.; Tütüncüler, F.; Baş, F.; Darendeliler, F.; Selimoğlu, M.A.; Hatun, Şükrü; Yeşiltepe Mutlu, Rahime Gül; Kızılkan, Nuray Uslu; Taşkın, Orhun Çığ; Faculty Member; Faculty Member; Faculty Member; School of Medicine; Koç University Hospital; 153504; 153511; 221274; 166686It is well-known that in children with type 1 diabetes (T1D), the frequency of Celiac disease (CD) is increased due to mechanisms which are not fully elucidated but include autoimmune injury as well as shared genetic predisposition. Although histopathologic examination is the gold standard for diagnosis, avoiding unnecessary endoscopy is crucial. Therefore, for both clinicians and patients’ families, the diagnosis of CD remains challenging. In light of this, a joint working group, the Type 1 Diabetes and Celiac Disease Joint Working Group, was convened, with the aim of reporting institutional data and reviewing current international guidelines, in order to provide a framework for clinicians. Several controversial issues were discussed: For CD screening in children with T1D, regardless of age, it is recommended to measure tissue transglutaminase-immunoglobulin A (tTG-IgA) and/or endomysial-IgA antibody due to their high sensitivity and specificity. However, the decision-making process based on tTG-IgA titer in children with T1D is still debated, since tTG-IgA titers may fluctuate in children with T1D. Moreover, seronegativity may occur spontaneously. The authors’ own data showed that most of the cases who have biopsy-proven CD had tTG-IgA levels 7-10 times above the upper limit. The decision for endoscopy based solely on tTG-IgA levels should be avoided, except in cases where tTG-IgA levels are seven times and above the upper limit. A closer collaboration should be built between divisions of pediatric endocrinology and gastroenterology in terms of screening, diagnosis and follow-up of children with T1D and suspicious CD.Publication Open Access Improving CO2 separation performance of MIL-53(Al) by incorporating 1-N-Butyl-3-methylimidazolium methyl sulfate(Wiley, 2019) Department of Chemical and Biological Engineering; N/A; Kulak, Harun; Polat, Hüsamettin Mert; Kavak, Safiyye; Keskin, Seda; Uzun, Alper; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); Graduate School of Sciences and Engineering; N/A; N/A; N/A; 40548; 599171-n-Butyl-3-methylimidazolium methyl sulfate is incorporated into MIL-53(Al). Detailed characterization is done by X-ray fluorescence, Brunauer-Emmett-Teller surface area, scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. Results show that ionic liquid (IL) interacts directly with the framework, significantly modifying the electronic environment of MIL-53(Al). Based on the volumetric gas adsorption measurements, CO2, CH4, and N-2 adsorption capacities decreased from 112.0, 46.4, and 19.6 cc (STP) g(MIL-53(Al))(-1) to 42.2, 13.0, and 4.3 cc (STP) g(MIL-53(Al))(-1) at 5 bar, respectively, upon IL incorporation. Data show that this postsynthesis modification leads to more than two and threefold increase in the ideal selectivity for CO2 over CH4 and N-2 separations, respectively, as compared with pristine MIL-53(Al). The isosteric heat of adsorption (Qst) values show that IL incorporation increases CO2 affinity and decreases CH4 and N-2 affinities. Cycling adsorption-desorption measurements show that the composite could be regenerated with almost no decrease in the CO2 adsorption capacity for six cycles and confirm the lack of any significant IL leaching. The results offer MIL-53(Al) as an excellent platform for the development of a new class of IL/MOF composites with exceptional performance for CO2 separation.Publication Open Access The urban renovation of Marseille in Luc Besson's Taxi series(Sage, 2016) Department of Media and Visual Arts; Rappas, İpek Azime Çelik; Faculty Member; Department of Media and Visual Arts; College of Social Sciences and HumanitiesSimilar to other post-industrial European cities, Marseille has been going through a process of intense urban renewal over the last 20 years. The symptoms of these changes were indicated in the action film series Taxi as early as the 1990s, when the renewal was beginning to take shape. Four films shot between 1998 and 2007, written and produced by Luc Besson, reflect the urgency felt by the government and commerce in Marseille to promote the city as the Mediterranean capital of global finance and tourism. This article first examines the process of urban renovation in Marseille. After a brief discussion on the city's representation in cinema, the article considers the film industry's interest in post-industrial urban spaces. Finally, it explores how the Taxi series prefigures the city that the urban renewal aspires to: a Marseille rendered more attractive for investments and tourists thanks to increased security measures and sanitised ethnic diversity.Publication Open Access Mutations in AR or SRD5A2 genes: clinical findings, endocrine pitfalls, and genetic features of children with 46,XY DSD(Galenos Yayınevi, 2022) Akcan, Neşe; Uyguner, Oya; Baş, Firdevs; Toksoy, Güven; Karaman, Birsen; Abalı, Zehra Yavaş; Poyrazoğlu, Şükran; Aghayev, Agharza; Karaman, Volkan; Bundak, Ruveyde; Basaran, Seher; Darendeliler, Feyza; Altunoğlu, Umut; Avcı, Şahin; Faculty Member; Faculty Member; School of Medicine; 126174; N/AObjective: androgen insensivity syndrome (AIS) and 5 alpha-reductase deficiency (5 alpha-RD) present with indistinguishable phenotypes among the 46,XY disorders of sexual development (DSD) that usually necessitate molecular analyses for the definitive diagnosis in the prepubertal period. The aim was to evaluate the clinical, hormonal and genetic findings of 46,XY DSD patients who were diagnosed as AIS or 5 alpha-RD. Methods: patients diagnosed as AIS or 5 alpha-RD according to clinical and hormonal evaluations were investigated. Sequence variants of steroid 5-alpha-reductase type 2 were analyzed in cases with testosterone/dihydrotestosterone (T/DHT) ratio of >= 20, whereas the androgen receptor (AR) gene was screened when the ratio was <20. Stepwise analysis of other associated genes were screened in cases with no causative variant found in initial analysis. For statistical comparisons, the group was divided into three main groups and subgroups according to their genetic diagnosis and T/DHT ratios. Results: a total of 128 DSD patients from 125 non-related families were enrolled. Birth weight SDS and gestational weeks were significantly higher in 5 alpha-RD group than in AIS and undiagnosed groups. Completely female phenotype was higher in all subgroups of both AIS and 5 alpha-RD patients than in the undiagnosed subgroups. In those patients with stimulated T/DHT <20 in the prepubertal period, stimulated T/DHT ratio was significantly lower in AIS than in the undiagnosed group, and higher in 5 alpha-RD. Phenotype associated variants were detected in 24% (n=18 AIS, n=14 5 alpha-RD) of the patients, revealing four novel AR variants (c.94G>T, p.Glu32*, c.330G>C, p.Leu110=; c.2084C>T, p.Pro695Leu, c.2585_2592delAGCTCCTG, p.(Lys862Argfs*16), of these c.330G>C with silent status remained undefined in terms of its causative effects. Conclusion: T/DHT ratio is an important hormonal criterion, but in some cases, T/DHT ratio may lead to diagnostic confusion. Molecular is for the robust of 46,XY DSD Four novel AR variants were identified in our study.Publication Open Access Hydrothermal-electrochemical growth of heterogeneous zno: co films(SpringerOpen, 2017) Department of Chemistry; Akkaya, Ceren Yılmaz; Ünal, Uğur; PhD Student; Faculty Member; Department of Chemistry; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); College of Sciences; Graduate School of Sciences and EngineeringBACKGROUND: Central venous cannulation is a necessary invasive procedure for fluid management, haemodynamic monitoring and vasoactive drug therapy. The right internal jugular vein (RIJV) is the preferred site. Enlargement of the jugular vein area facilitates catheterization and reduces complication rates. Common methods to enlarge the RIJV cross-sectional area are the Trendelenburg position and the Valsalva maneuver. OBJECTIVE: Compare the Trendelenburg position with upper-extremity venous return blockage using the tourniquet technique. DESIGN: Prospective clinical study. SETTING: University hospital. SUBJECTS AND METHODS: Healthy adult volunteers (American Society of Anesthesiologists class I) aged 18-45 years were included in the study. The first measurement was made when the volunteers were in the supine position. The RIJV diameter and cross-sectional area were measured from the apex of the triangle formed by the clavicle and the two ends of the sternocleidomastoid muscle, which is used for the conventional approach. The second measurement was performed in a 20 degrees Trendelenburg position. After the drainage of the veins using an Esbach bandage both arms were cuffed. The third measurement was made when tourniquets were inflated. MAIN OUTCOME MEASURE(S): Hemodynamic measurements and RIJV dimensions. RESULTS: In 65 volunteers the diameter and cross-sectional area of the RIJV were significantly widened in both Trendelenburg and tourniquet measurements compared with the supine position (P<.001 for both measures). Measurements using the upper extremity tourniquet were significantly larger than Trendelenburg measurements (P=.002 and <.001 for cross-sectional area and diameter, respectively). CONCLUSION: Channelling of the upper-extremity venous return to the jugular vein was significantly superior when compared with the Trendelenburg position and the supine position. LIMITATIONS: No catheterization and study limited to healthy volunteers.Publication Open Access Kidney exchange: an egalitarian mechanism(Elsevier, 2011) Department of Economics; Yılmaz, Özgür; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 108638Kidney exchange programs utilize both deceased-donor and live-donor kidneys. One of these programs, a two-way kidney paired donation (KPD), involves two patients exchanging their live donors' kidneys. Another possibility is a list exchange (LE): a living incompatible donor provides a kidney to a candidate on the deceased-donor waitlist and in return the intended recipient of this donor receives a priority on the waitlist. By taking into consideration the fact that transplants from live donors have a higher chance of success than those from cadavers, we characterize the set of efficient and egalitarian exchanges involving the KPD's and LE's.Publication Open Access Generalized adiabatic product expansion: a nonperturbative method of solving the time-dependent Schrodinger equation(American Institute of Physics (AIP) Publishing, 1999) Department of Mathematics; Mostafazadeh, Ali; Faculty Member; Department of Mathematics; College of Sciences; 4231We outline a method based on successive canonical transformations which yields a product expansion for the evolution operator of a general (possibly non-Hermitian) Hamiltonian. For a class of such Hamiltonians this expansion involves a finite number of terms, and our method gives the exact solution of the corresponding time-dependent Schrödinger equation. We apply this method to study the dynamics of a general nondegenerate two-level quantum system, a time-dependent classical harmonic oscillator, and a degenerate system consisting of a spin 1 particle interacting with a time-dependent electric field ℰ→(t) through the Stark Hamiltonian H = λ(J→ · ℰ→)2.Publication Open Access Assessment of the optic nerve, optic disc, and perineural area using shear-wave elastography in patients with multiple sclerosis(Wiley, 2021) Şahin Ediz, Suna; Atalay, Başak; Aydın Cantürk, İlknur; Kabaalioğlu, Adnan; Faculty Member; Koç University HospitalPurpose: to observe and describe the stiffness changes of the optic nerve in the patients with multiple sclerosis (MS) with or without optic neuritis and healthy adults via shear wave elastography (SWE). Methods: 70 optic nerves from 35 patients with MS and 60 optic nerves from 30 healthy subjects were included prospectively in the study. The optic nerve (ON), optic disc (OD), and perineural area were evaluated with SWE and optic nerve sheat diameter (ONSD) was measured by ultrasound. Results: The mean age of patients was 39.68 +/- 9.99 years. There was no statistically significant difference between the groups in terms of ONSD, SWE ON, SWE OD, and SWE perineural area levels (P > .05). In the MS group; No statistically significant difference was found between patients with and without optic neuritis for the mean age, gender distribution, duration of MS, types of MS, ONSD, SWE ON, SWE OD, SWE perineural area, and Expanded Disability Status Scale (EDSS) scores (P > .05). No statistically significant difference in terms of ONSD, SWE ON, SWE OD, and SWE perineural area between the MS patients with or without optic neuritis and the control group (P > .05). Conclusion: shear wave elastography measurements of the optic nerve, optic disc, and perineural area do not contribute to the evaluation of optic neuritis in a patient with MS.Publication Open Access COVID-19 in kidney transplant recipients: a multicenter experience in Istanbul(Wiley, 2020) Demir, Erol; Uyar, Murathan; Parmaksız, Ergün; Sinangil, Ayşe; Dirim, Ahmet Burak; Merhametsiz, Özgür; Yadigar, Serap; Atan Uçar, Zuhal; Uçar, Ali Rıza; Demir, Mehmet Emin; Meşe, Meral; Akın, Emin Barış; Garayeva, Nurana; Şafak, Seda; Oto, Özgür Akın; Yazıcı, Halil; Yelken, Berna; Türkmen, Aydın; Doctor; School of MedicineIntroduction: Management of COVID-19 in kidney transplant recipients should include treatment of the infection, regulation of immunosuppression, and supportive therapy. However, there is no consensus on this issue yet. This study aimed to our experiences with kidney transplant recipients diagnosed with COVID-19. Material and Methods: Kidney transplant recipients diagnosed with COVID-19 from five major transplant centers in Istanbul, Turkey, were included in this retrospective cohort study. Patients were classified as having moderate or severe pneumonia for the analysis. The primary endpoint was all-cause mortality. The secondary endpoints were acute kidney injury, the average length of hospital stay, admission to intensive care, and mechanical ventilation. Results: Forty patients were reviewed retrospectively over a follow-up period of 32 days after being diagnosed with COVID-19. Cough, fever, and dyspnea were the most frequent symptoms in all patients. The frequency of previous induction and rejection therapy was significantly higher in the group with severe pneumonia compared to the moderate pneumonia group. None of the patients using cyclosporine A developed severe pneumonia. Five patients died during follow-up in the intensive care unit. None of the patients developed graft loss during follow-up. Discussion: COVID-19 has been seen to more commonly cause moderate or severe pneumonia in kidney transplant recipients. Immunosuppression should be carefully reduced in these patients. Induction therapy with lymphocyte-depleting agents should be carefully avoided in kidney transplant recipients during the pandemic period.Publication Open Access The influence of ecological traits and environmental factors on the co-occurrence patterns of birds on islands worldwide(Wiley, 2020) Sato, Eri; Kusumoto, Buntarou; Kubota, Yasuhiro; Murakami, Masashi; Department of Molecular Biology and Genetics; Şekercioğlu, Çağan Hakkı; Faculty Member; Department of Molecular Biology and Genetics; College of SciencesTo understand the mechanisms shaping global species diversity patterns, we focused on species assembly of bird communities on islands, which are ideal for detecting ecological and historical processes. We tested the hypotheses that species traits and island environments interactively shape the phylogenetic structure of island bird assemblages through a variety of ecological processes: habitat filtering, in-situ speciation, extinction, dispersal limitation and competitive exclusion. We assessed the effects of species ecological traits and environment factors on the phylogenetic fields, which defined as phylogenetic distance between individual bird species and co-occurred species within each island, using phylogenetic generalized linear mixed models. Climate and isolation were the most important factors driving the co-occurrence patterns of island bird species: the species' phylogenetic fields were significantly clustered on tropical and/or isolated islands. We also found that the phylogenetic fields strongly correlated with the ecological traits especially for the diet and habitat preferences: the phylogenetic fields tended to over-disperse for granivores and species inhabiting in wetlands or coasts, while frugivores showed clustered phylogenetic fields. Moreover, mobility and body size had substantial effects on species assemblages: long-distance dispersers had clustered phylogenetic fields and small-bodied species showed overdispersed phylogenetic fields.