50 research outputs found

    Tailoring the structural properties and electronic structure of anatase, brookite and rutile phase TiO2 nanoparticles: DFTB calculations

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    In this study, we perform a theoretical investigation using the density functional tight-binding (DFTB) approach for the structural analysis and electronic structure of anatase, brookite and rutile phase TiO2 nanoparticles (NPs). Our results show that the number of Ti-O bonds is greater than that of O-O, while the number of Ti-Ti bonds is fewer. Thus, large amounts of O atoms prefer to connect to Ti atoms. The increase in the temperature of the NPs contributes to an increase in the interaction of Ti–O bonding, but a decrease in the O-O bonding. The segregation of Ti and O atoms shows that Ti atoms tend to co-locate at the center, while O atoms tend to reside on the surface. Increasing temperature causes a decrease of the bandgap from 3.59 to 2.62 eV for the brookite phase, which is much more energetically favorable compared to the bulk, while it could increase the bandgap from 3.15 to 3.61 eV for anatase phase. For three-phase TiO2 NPs, LUMO and Fermi levels decrease. The HOMO level of anatase phase NP decreases, but it increases for brookite and rutile phase TiO2 nanoparticles. An increase in the temperature contributes to the stabilization of anatase phase TiO2 NP due to a decrease in the HOMO energies. © 2020 Elsevier B.V

    Determination of the morphometric characteristics of donkey (Equus asinus) populations reared in Turkey

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    This research aims to determine the morphometric characteristics of the donkey (Equus asinus) populations reared in Turkey. For this purpose, live weights and body measurements were collected from 500 donkeys. The donkeys were grouped according to the factors of color, age, sex, and province and the live weights (LW) (kg), withers heights (WH), rump heights (RH), body lengths (BL), chest circumferences (CC), chest depths (CD), front shank circumferences (FSC), head lengths (HL) and ear lengths (EL) (cm) of the donkeys were measured. In the study, the males were found to have higher values of live weight, withers height, rump height, and chest depth than the females (p < 0.05). Significant differences in the live weights of the donkeys were seen by province, age, color, and sex (p < 0.01 and p < 0.05). Significant differences were found among the age groups as well (p < 0.01). Accordingly, the least squares means of the animals aged 1???3 years, 4???5 years, 6???8 years, and 9 years and over for live weight were measured as 112.10 ?? 3.11 kg, 141.54 ?? 2.76 kg, 153.98 ?? 2.42 kg, and 152.95 ?? 2.34 kg, respectively. The least squares mean of live weights were also determined as significant between the female and male animals (138.08 ?? 1.96 kg) and (142.21 ?? 2.25 kg), respectively (p 0.05). The highest correlation coefficient was calculated between live weight and body length among the donkeys (r = 0.83). Furthermore, the classical method (CM) and the fixed object photo (FOP) method were compared for photographed animals in the study. No difference in WH, RH, CD or HL was seen between the two methods (p 0.05). In conclusion, the morphometric characteristics of the donkeys were determined and it was shown that the populations were not distinguished clearly from each other and that this was fundamentally due to the transitions among the donkey populations for long years

    COVID-19 in pediatric nephrology centers in Turkey

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    Background/aim: There is limited data on COVID-19 disease in children with kidney disease. We aimed to investigate the characteristics and prognosis of COVID-19 in pediatric nephrology patients in Turkey. Materials and methods: This was a national, multicenter, retrospective cohort study based on an online survey evaluating the data between 11th March 2020 and 11th March 2021 as an initial step of a detailed pediatric nephrology COVID-19 registry. Results: Two hundred and three patients (89 girls and 114 boys) were diagnosed with COVID-19. One-third of these patients (36.9%) were between 10–15 years old. Half of the patients were on kidney replacement therapy: kidney transplant (KTx) recipients (n = 56, 27.5%), patients receiving chronic hemodialysis (n = 33, 16.3%) and those on peritoneal dialysis (PD) (n = 18, 8.9%). Fifty-four (26.6%) children were asymptomatic. Eighty-two (40.3%) patients were hospitalized and 23 (28%) needed intensive care unit admission. Fifty-five percent of the patients were not treated, while the remaining was given favipiravir (20.7%), steroid (16.3%), and hydroxychloroquine (11.3%). Acute kidney injury developed in 19.5% of hospitalized patients. Five (2.4%) had MIS-C. Eighty-three percent of the patients were discharged without any apparent sequelae, while 7 (3.4%) died. One hundred and eight health care staff were infected during the study period. Conclusion: COVID-19 was most commonly seen in patients who underwent KTx and received HD. The combined immunosuppressive therapy and frequent exposure to the hospital setting may increase these patients’ susceptibility. Staff infections before vaccination era were alarming, various precautions should be taken for infection control, particularly optimal vaccination coverage

    Examining the Contribution of Physical Education and Sports Courses in the Secondary School to the Sportsmanship Behaviours in Terms of Some Variables

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    This study was carried out in order to determine the contribution of the physical education and sports classes in the secondary school to the sportsmanship behaviours in terms of some variables. The population of the study, which was carried out using a general screening model, consists of students from the government - dependent secondary schools in the county, of Malatya Battalgazi, and its sampling consists of 670 students, studying at “Atatürk, Barbaros, Türk Telekom, Türkiye’m and Vakifbank” public secondary schools in the city centre of Malatya, chosen from the these schools by a random method. In the research, "Physical Education Courses Sportsmanship Behaviours Scale" is used as a data collec ting tool. Analysis of data obtained from the research was conducted with the help of a SPSS 20 package program and arithmetic mean, t - test and one - way analysis of variance (ANOVA) were used in the calculation. As the result of the study, relying on the an swers the students have given to the scale it has been determined that the overall arithmetic mean of the scale was lower than expected, that the views on the contribution of the physical education and sports classes to sportsmanship behaviours were equiva lent to each other depending on the demographic variables of gender and father’s education level, however, there were significant differences among students depending on the grade level

    Effects of metal surface grinding at the porcelain try-in stage of fixed dental prostheses

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    PURPOSE. This study was to evaluate the effect of grinding of the inner metal surface during the porcelain try-in stage on metal-porcelain bonding considering the maximum temperature and the vibration of samples. MATERIALS AND METHODS. Ninety-one square prism-shaped (1 x 1 x 1.5 mm) nickel-chrome cast frameworks 0.3 mm thick were prepared. Porcelain was applied on two opposite outer axial surfaces of the frameworks. The grinding was performed from the opposite axial sides of the inner metal surfaces with a low-speed handpiece with two types of burs (diamond, tungsten-carbide) under three grinding forces (3.5 N, 7 N, 14 N) and at two durations (5 seconds, 10 seconds). The shear bond strength (SBS) test was performed with universal testing machine. Statistical analyzes were performed at 5% significance level. RESULTS. The samples subjected to grinding under 3.5 N showed higher SBS values than those exposed to grinding under 7 N and 14 N (P.05). The types of bur (P=.965) and the duration (P=.679) did not affect the SBS values. On the other hand, type of bur, force applied, and duration of the grinding affected the maximum temperatures of the samples, whereas the maximum vibration was affected only by the type of bur (P<.05). CONCLUSION. Grinding the inner metal surface did not affect the metalporcelain bond strength. Although the grinding affected the maximum temperature and the vibration values of the samples, these did not influence the bonding strength

    Does Retinal Neurodegeneration Seen in Diabetic Patients Begin in the Insulin Resistance Stage?

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    Objectives: To investigate whether retinal neurodegeneration and impairment in contrast sensitivity (CS), which have been demonstrated to begin in diabetic patients before the presence of signs of diabetic retinal vasculopathy, also occur in the stage of insulin resistance. Materials and Methods: The average, minimum and sectoral (inferior, superior, inferonasal, superonasal, inferotemporal and superotemporal) thicknesses of ganglion cell-inner plexiform layer (GCIPL) measured using optical coherence tomography were compared between an insulin-resistant group and control group in order to evaluate the presence of retinal neurodegeneration. The CS of the two groups was also compared according to the logarithmic values measured at spatial frequencies of 1.5, 3, 6, 12 and 18 cycles per degree in photopic light using functional acuity contrast test (FACT). Results: Twenty-five eyes of 25 patients with insulin resistance (insulin resistant group) and 25 eyes of 25 healthy subjects (control group) were included in this study. There were no statistically significant differences between two groups in any of the spatial frequencies in the FACT. The mean average GCIPL thickness and mean GCIPL thickness in the inferotemporal sector were significantly less in the insulin-resistant group when compared with the control group (mean average GCIPL thicknesses in the insulin-resistant and control groups were 83.6±4.7 µm and 86.7±3.7 µm respectively, p=0.01; mean inferotemporal GCIPL thicknesses in the insulin-resistant and control groups were 83±6.0 µm and 86.7±4.6 µm respectively, p=0.02). Conclusion: Although it may not lead to functional impairment in vision such as CS loss, the retinal neurodegeneration seen in diabetic patients may also occur in the insulin resistance stage

    Predictors of Anticoagulant Treatment in Patients With Nonvalvular Atrial Fibrillation: Results From Atrial Fibrillation in Turkey: Epidemiologic Registry

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    cagliyan, caglar/0000-0002-2529-4995; Kaya, Hasan/0000-0003-3923-4026WOS: 000350492000007PubMed: 23742948The aim of the study was to assess the factors associated with the anticoagulation treatment in patients with atrial fibrillation (AF). A total of 2242 consecutive patients who had been admitted with AF on their electrocardiogram were included in the study. After excluding valvular AF, 1745 patients with nonvalvular AF were analyzed. Mean CHA2DS2-VASc score [cardiac failure, hypertension, age >= 75 (doubled), diabetes, stroke (doubled), vascular disease, age 65 -74 and sex category (female)], frequency of persistent/permanent AF, hypertension, diabetes mellitus (DM), stroke history, body mass index, and left atrial diameter were significantly higher in patients receiving anticoagulant therapy. Stroke history, persistent/permanent AF, hypertension, DM, age, heart failure, and left atrial diameter were independent predictors of warfarin prescription. Labile international normalized ratio was the only independent negative predictor of effective treatment with warfarin. In this study, we demonstrated that stroke history, persistent/permanent AF, hypertension, DM, and left atrial diameter were positive predictors, whereas advanced age and heart failure were negative predictors of oral anticoagulant use in patients with nonvalvular AF
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