Aksaray University Institutional Repository
Not a member yet
8503 research outputs found
Sort by
Investigation of physical properties of some two dimensional crystals containing transition metals by Ab initio methods
No full textBu çalışmada, yoğunluk fonksiyonel teorisinden yararlanarak 2 boyutlu bazı kristallerin fiziksel özellikleri farklı yaklaşımlar altında incelenmiştir. Yapılan hesaplamalar sonucunda PbI2 bileşiğinin sahip olduğu ultra düşük termal iletkenliğin kökenleri Slack teorisi çerçevesinde incelenerek açıklanmıştır. Mo2ScC2, Mo2ScC2T2 (T=O, F) ve Mo2ScC2OH MXene bileşikleri üzerine yapılan çalışmalar bileşiklerin mekaniksel ve dinamiksel olarak kararlı olduğunu göstermiştir. Elektronik bant yapı hesaplamaları bu bileşiklerin metalik karakterde olduğunu ortaya koymuştur. Sonuçlar, Mo2ScC2O2 bileşiğinin Young modülü değerinin oldukça yüksek olduğu göstermiştir. Mo2ScC2OH bileşiğinin yüksek Grüneisen parametresine ve negatif termal genleşme katsayısına sahip bir bileşik olduğunu ortaya çıkmıştır. Mo2ScC2 bileşiğinin yüksek elektronik transport katsayılarına sahip olduğu görülmüştür. Mo2C bileşiğinin auxetic bir malzeme olduğu belirlenmiştir. Co atomları ile yapılan katkılama sonucunda Mo2C bileşiğinin manyetik özellik kazandığı ve transport özelliklerinin önemli ölçüde etkilendiği anlaşılmıştır. Kusurlu Mo2ScC2O2 üzerine yapılan elektronik ve transport hesaplamalar Mo2ScC2O2'nin metalik doğasının korunduğu ve bu tür bir kusurun elektronik transport özelliklerini önemli ölçüde etkilemediğini göstermiştir. 1T-MoS2 ve 2H-MoS2 bileşiklerinin yük transfer dinamiği incelenmiş ve açıklanmıştır. NbSe2 bileşiğinin elektronik ve manyetik özellikleri incelenmiş ve sonuçlar süperiletken olan NbSe2'nin ayrıca manyetik özellik sergileyebildiğini de göstermiştir. Son olarak 2D Cu2Te bileşiğinin yarı iletken karakterde olduğu gözlenmiş ve mekaniksel özellikleri ile termal ve elektronik transport özellikleri incelenmiştir. Termoelektrik performansının ve örgü termal iletkenliğinin doğası açıklanmıştır.In this study, the physical properties of some 2 dimensional crystals are investigated by using the density functional theory under different approaches. As a result of the calculations, the origins of the ultra low thermal conductivity of PbI2 compound were investigated and explained within the frame of the Slack theory. Studies on Mo2ScC2, Mo2ScC2T2 (T=O, F), and Mo2ScC2OH MXene compounds have shown that compounds are both mechanically and dynamically stable. Electronic band structure calculations have revealed that these compounds have metallic character. The results showed that Young's modulus of Mo2ScC2O2 compound was quite high. It was revealed that the Mo2ScC2OH compound has high Grüneisen parameter and negative coefficient of thermal expansion. It has been observed that Mo2ScC2 compound has high electronic transport coefficients. It has been determined that Mo2C compound is in an auxetic material. It has been understood that as a result of doping with Co atoms, the Mo2C compound gained magnetic properties, and its transport properties were significantly affected. The electronic and transport calculations on Mo2ScC2O2 showed that the metallic nature of this compound was preserved and such a defect did not significantly affect the electronic transport properties. The charge transfer dynamics of 1T-MoS2 and 2H-MoS2 compounds are studied and explained. Electronic and magnetic properties of NbSe2 compound were investigated and the results showed that the superconducting NbSe2 can also exhibit magnetic properties. Finally, it has been observed that 2D Cu2Te compound has semiconductor character, and its mechanical, thermal, and electronic transport properties are examined. The nature of its thermoelectric performance and lattice thermal conductivity is explained
First protein affinity application of Cu2+-bound pure inorganic nanoflowers
Get PDF*Önal, Burcu ( Aksaray, Yazar )Today, a new kind of materials is introduced to separation media day by day to increase the efficiency of the separation processes, and multiple-petalled nanostructured materials are one of them. In this study, new pure inorganic copper phosphate nanoflowers (pCP-NFs) were synthesized, and some environmental conditions affecting on binding mechanism with human serum albumin were evaluated via changing medium pH, temperature, initial human serum albumin (HSA) amount and salt concentrations. Before experimental studies, pCP-NFs were subjected to some characterization tests such as scanning electron microscopy, energy-dispersive X-ray, X-ray diffraction and Fourier transform infrared spectroscopy. Besides a lot of valuable instrumental data, some obtained experimental ones as follows: after Cu2+ ions attachment to pCP-NFs as ligand, maximum HSA adsorption capacity of obtained Cu2+-pCP-NFs was found as 225.7 mg/g with an initial concentration of 1.5 mg/mL at pH 7 and 25 degrees C. Langmuir and Freundlich adsorption equations were evaluated for determination of appropriate adsorption model in interaction, and Langmuir model found as the fittest one with a R-2 of 0.9949 was also reviewed to determine Gibbs free energy between HSA and Cu2+-pCP-NFs interaction
Impact of chronic medical conditions on mortality in geriatric trauma, 10-year analysis of a single centre in Turkey
Get PDFBackground
The healthy and active lifestyle adopted by the elderly as a result of improvements in the standards of living may lead to an increase in the risk of injury. Comorbidities increase the risk of posttraumatic complications and mortality. The aim of this study was to investigate the impact of chronic medical conditions (CMCs) on the risk of mortality in geriatric trauma patients.
Methods
All geriatric trauma patients admitted to emergency department over a 10-year period were retrospectively analysed. Patients were stratified by baseline characteristics, injury severity score (ISS), presence of CMCs, and in-hospital mortality. Multivariate logistic regression was used to determine variables significantly associated with in-hospital mortality.
Results
9455 patients included in the study. The median age was 74 (10) years and 57% of them were female. The presence of >= 1 CMC and >= 2 CMCs increased the risk of mortality 5.64 and 2.38 times respectively in mild traumas and 2.67 and 2.59 times respectively in moderate traumas. Age, ISS and penetrating traumas had a significant impact on the risk of mortality in all ISS groups. In severe traumas, only renal disease had an impact on the risk of mortality (OR = 2.58, 95%CI = 1.03-6.43, p = 0.042). All other CMCs, >= 1 CMC, and >= 2 CMCs had no impact on the risk of mortality.
Conclusion
The presence of CMCs in elderly patients with mild and moderate injuries increases the risk of mortality. Such patients should be diagnosed and treated more quickly and aggressively during the prehospital process and in the hospital
Low‑cost organic adsorbent usage for removing Ni2+ and Pb2+ from aqueous solution and adsorption mechanisms
No full textThis study aimed to investigate Ni2+ and Pb2+ removal by using pistachio, peanut, and almond shells from an aqueous medium. The contact time, pH, and biosorbent dosage effects on the sequestration of nickel and lead were evaluated. Optimum adsorption of metal ions at pH value of 6.0, contact time 45 min at room temperature with 1.0 g adsorbent was found. The sorption process of metal ions was well defined by the pseudo-second-order kinetic model and Freundlich isotherm for nickel and Langmuir isotherm for the lead. The adsorption capacity for nickel and lead was obtained in the order of pistachio shell (72.46 mg g−1) > almond shell (71.94 mg g−1) > peanut shell (60.97 mg g−1), and almond shell (48.14 mg g−1) > peanut shell (37.14 mg g−1) > pistachio shell (36.73 mg g−1), respectively. The FTIR spectra and SEM images were used to characterize the adsorbents. FTIR analysis demonstrates that the surface carboxylic/hydroxyl functional groups of organic residuals are responsible for the adsorption of Ni2+ and Pb2+. Various mechanisms including the electrostatic interaction, ion exchange, metal complexation, physical/chemical adsorption take place in the adsorption process. The results indicate that pistachio, peanut, and almond shell, locally available organic residuals, are efficient and green adsorbent for the reduction of Ni2+ and Pb2+. According to their adsorption capacity, pistachio shell for Ni2 + and almond shell for Pb2 + can be recommended
Stability and Anisotropic Elastic Properties of a Hexagonal δ-WN Compound
No full textIn this work, we have examined the structural, phonon and anisotropic elastic properties of a hexagonal δ-WN compound via density functional theory. The obtained structural parameters and mechanical properties are in agreement with the other experimental and theoretical results. The present phonon dispersion curve and elastic constants indicate that the δ-WN compound is both mechanically and dynamically stable. The predicted elastic modulus shows that this compound possesses a high bulk modulus, shear modulus and Young’s modulus. The tabulated B/G and Poisson’s ratio have predicted that δ-WN has ductile behavior. According to the calculated minimum thermal conductivity, the hexagonal δ-WN compound can be used as thermal insulating material. Moreover, elastic anisotropy behavior has been analyzed with the different anisotropic indexes. The anisotropic elastic properties have been reported and discussed for the first time
Extended fully improved quadrature spatial shift keying modulation
No full textIn this paper, extended fully improved quadrature space shift keying (EFIQSSK) modulation, which is a combination of extended quadrature spatial modulation (EQSM) scheme and fully improved quadrature space shift keying (FIQSSK), is proposed. EFIQSSK uses only antenna indices to modulate data bits, achieving a bit rate of four times the number of antennas per channel usage. The proposed scheme can be implemented with any number of antennas. It has a low complexity since it does not need any radio frequency (RF) chain on the transmitter side. In our study, the bit error rate performance of this technique is compared with the schemes in the literature with the same spectral efficiency. In addition, the transmission scheme used in the method has been optimized to provide low bit error. In the Monte Carlo simulations, it has been observed that the proposed scheme outperforms other schemes in the literature with the same spectral efficiency when using 3 or more transmit antennas
Risk factors of deaths related to cardiovascular diseases in World Health Organization (WHO) member countries
Get PDFThis study aims to identify the risk factors affecting deaths related to cardiovascular diseases. The research population comprised of 194 World Health Organization (WHO) member countries, but the data analysis was conducted with the data from 152 countries as 42 of them do not have any data on study variables. Multivariable regression analysis was utilised for this study to analyse the effect of factors regarding metabolism, lifestyle, economic, socio-demographic and health system on the cardiovascular diseases related to deaths. As a result of regression analysis, the number of deaths related to cardiovascular diseases increases with the increase in blood pressure (p < .001), blood glucose (p = .032), obesity rate (p < .001), salt consumption (p < .001), GINI index (p = .002) and dependent age ratio (p < .001); the frequency of cardiovascular disease-related deaths is higher in the countries within low (p < .001) and high (p < .001) middle-income levels; yet, the number of deaths based on cardiovascular diseases diminishes with the increase in the number of doctors (p = .005) and health expenditures per capita (p = .044). The research findings are considered to guide the countries in the determination of their steps towards the prevention of deaths related to cardiovascular diseases
The effectiveness of mindfulness-based interventions on the psychological well-being of nurses: A systematic review
Get PDFThere is a rising demand for methods to support well-being at work. Mindfulness-based interventions have the potential to enhance nurses' psychological well-being. Purpose: To identify mindfulness-based interventions and outcome measures and to evaluate the effect on the psychological well-being of nurses. Methods: A systematic review following Prisma protocol with search of four electronic databases was undertaken covering English language publications between January 2011 and July 2021. Findings: A total of 11 randomized controlled trial (RCT) and quasi-experimental studies with a total of 1009 participants were included. The outcome measures were stress, depression, anxiety, burnout, resilience, quality of life, self-compassion, happiness, and the level of mindfulness. Ten studies demonstrated positive impact of mindfulness-based intervention on nurses' psychological well-being. Discussion: Mindfulness-based interventions have the potential to enhance the well-being of nurses. RCTs using rigorous designs, consistent outcome measures and bigger sample sizes are required to determine the effectiveness of mindfulness programs
Drug-induced poisoning during pregnancy: Four-year experience
No full textThe aim of this study was to define the population of pregnant women who presented to our clinic after drug exposure for suicidal purposes and to determine the effect of drug-induced poisoning on maternal and fetal outcomes. Methods: The records of patients who presented to the emergency department after a suicide attempt with drugs between 2017 and 2021 were retrospectively reviewed. Pregnant women aged 18 years and over who delivered their babies in our hospital were included in the study. Patient data were obtained from the hospital electronic database using the International Classification of Disease-10 code system. Demographic information, clinical characteristics, type of drugs ingested, pregnancy outcomes, and perinatal outcomes were recorded. Results: We found adverse pregnancy outcomes in five of the 28 patients included in the study. The most frequently used drugs for suicidal purposes were non-opioid analgesics, paracetamol, and antibiotics (39.3%, 35.7%, and 28.6%, respectively). Adverse pregnancy outcomes observed in the patients were preterm birth (n = 3), preeclampsia (n = 2), premature rupture of membranes (n = 1), fetal distress (n = 2), small for gestational age (n = 2), Apgar score at 5 min < 7 (n = 1), and requirement of neonatal intensive care (n = 2). Conclusion: Pregnant women attempting suicide with drug exposure are at high risk of many adverse obstetric outcomes. Providing these patients with appropriate clinical care is critical for the health of the mother and fetus
Investigación de los efectos del cambio en el nivel de aguas subterráneas a partir de observaciones de sistemas globales de navegación por satélite en la Cuenca de Konya, Turquía
Get PDFThe Konya Closed Basin (KCB), inhabited by approximately 4 million people, has a semi-arid climate and has been an important agricultural and economic production area with its fertile alluvial soils. In recent years, groundwater use as a primary source in the intense need for irrigation due to climate change, drought, and wrong agricultural policies triggered land subsidence in the basin by causing the aquifer system compaction. In this study, the effects of groundwater level changes obtained from groundwater monitoring stations on the positions of continuously operating GNSS stations located in KCB were investigated by time series analysis. As a result of trend component analyses of time series processed based on the ITRF08 fixed frame, it was determined that the horizontal positions of stations in this region were moving in the northeast direction (18.74 mm/year). For the up coordinates, while stations ANRK, KLUU, and NIGD had movements 0.56 mm/year in the up direction, the other stations moved in the down direction. The vertical movement of the KNY1 station based on 560-day data was in the down (-) direction, with an annual movement of 70.96 mm, and this was the maximum movement or velocity compared to the other stations in this region. The trend analysis of 19 wells revealed linear groundwater level changes in the down direction with a mean value of-39.22 cm/year. The decrease in the water level of the wells in the Konya Closed Basin was statistically significant for the majority of the wells and at meter level in some wells