58 research outputs found

    Electronic and magnetic properties of the monolayer RuCl3_3: A first-principles and Monte Carlo study

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    Recent experiments revealed that monolayer α\alpha-RuCl3_3 can be obtain by chemical exfoliation method and exfoliation or restacking of nanosheets can manipulate the magnetic properties of the materials. In this present paper, the electronic and magnetic properties of α\alpha-RuCl3_3 monolayer are investigated by combining first-principles calculations and Monte Carlo simulations. From first-principles calculations, we found that the spin configuration FM corresponds to the ground state for α\alpha-RuCl3_3, however, the other excited zigzag oriented spin configuration has energy of 5 meV/atom higher than the ground state. Energy band gap has been obtained as 33 meV using PBE functionals. When spin-orbit coupling effect is taken into account, corresponding energy gap is determined to be as 5757 meV. We also investigate the effect of Hubbard U energy terms on the electronic band structure of α\alpha-RuCl3_3 monolayer and revealed band gap increases approximately linear with increasing U value. Moreover, spin-spin coupling terms (J1J_1, J2J_2, J3J_3) have been obtained using first principles calculations. By benefiting from these terms, Monte Carlo simulations with single site update Metropolis algorithm have been implemented to elucidate magnetic properties of the considered system. Thermal variations of magnetization, susceptibility and also specific heat curves indicate that monolayer α\alpha-RuCl3_3 exhibits a phase transition between ordered and disordered phases at the Curie temperature 14.2114.21 K. We believe that this study can be utilized to improve two-dimensional magnet materials

    Turner syndrome and associated problems in turkish children: A multicenter study

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    Objective: Turner syndrome (TS) is a chromosomal disorder caused by complete or partial X chromosome monosomy that manifests various clinical features depending on the karyotype and on the genetic background of affected girls. This study aimed to systematically investigate the key clinical features of TS in relationship to karyotype in a large pediatric Turkish patient population. Methods: Our retrospective study included 842 karyotype-proven TS patients aged 0-18 years who were evaluated in 35 different centers in Turkey in the years 2013-2014. Results: The most common karyotype was 45,X (50.7%), followed by 45,X/46,XX (10.8%), 46,X,i(Xq) (10.1%) and 45,X/46,X,i(Xq) (9.5%). Mean age at diagnosis was 10.2±4.4 years. The most common presenting complaints were short stature and delayed puberty. Among patients diagnosed before age one year, the ratio of karyotype 45,X was significantly higher than that of other karyotype groups. Cardiac defects (bicuspid aortic valve, coarctation of the aorta and aortic stenosi) were the most common congenital anomalies, occurring in 25% of the TS cases. This was followed by urinary system anomalies (horseshoe kidney, double collector duct system and renal rotation) detected in 16.3%. Hashimoto’s thyroiditis was found in 11.1% of patients, gastrointestinal abnormalities in 8.9%, ear nose and throat problems in 22.6%, dermatologic problems in 21.8% and osteoporosis in 15.3%. Learning difficulties and/or psychosocial problems were encountered in 39.1%. Insulin resistance and impaired fasting glucose were detected in 3.4% and 2.2%, respectively. Dyslipidemia prevalence was 11.4%. Conclusion: This comprehensive study systematically evaluated the largest group of karyotype-proven TS girls to date. The karyotype distribution, congenital anomaly and comorbidity profile closely parallel that from other countries and support the need for close medical surveillance of these complex patients throughout their lifespan. © Journal of Clinical Research in Pediatric Endocrinology

    Refugee children with beta-thalassemia in Turkey: Overview of demographic, socioeconomic, and medical characteristics

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    PubMedID: 30706992Aim: Since the beginning of the Syrian civil war, more than 3.5 million Syrians have been under temporary protection status in Turkey. Because beta-thalassemia (BT) is a prevalent disorder in the Mediterranean countries, we decided to estimate the prevalence of and make an overview of the demographic, socioeconomic, medical characteristics, and healthcare problems of refugee children with BT. Patients: Eighteen Turkish Pediatric Hematology Oncology Centers (PHOC) with 318 refugee children from 235 families participated in the study. The mean age of the patients was 8.1 ± 4.8 years (0.5–21 years). The mean time after immigration to Turkey was 2.5 ± 1.5 years (range, 0.1–7 years). Seventy-two (22.6%) of them were born and diagnosed with BT in Turkey. On physical examination, 82 patients (26%) were underweight and 121 patients (38%) were stunted. The appearance of a thalassemic face was reported for 207 patients (65.1%). Hepatomegaly and splenomegaly were reported in 217 (68.2%) and 168 (52.8%) patients, respectively. The median ferritin level was 2508 ng/mL (range, 17–21 000 ng/mL) at the first admission, and 2841 ng/mL (range, 26–12 981 ng/mL) at the last visit after two years of follow-up in a PHOC (P > 0.05). The most frequently encountered mutation was IVSI-110 (G>A) (31%). Before immigration, only 177 patients (55.6%) reported the use of chelators; after immigration it increased to 268 (84.3%). Conclusion: Difficulties in communication, finding a competent translator capable in medical terminology, nonregular use of medications, and insensitivity to prenatal diagnosis were preliminary problems. The current extent of migration poses emerging socioeconomic and humanitarian challenges for refugee patients with BT. © 2019 Wiley Periodicals, Inc
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