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Enformatik Dersi için Başarı Testi Geliştirme Çalışması: Güvenilirlik ve Geçerlilik İşlemleri
No full textEstablishment of an incentive system for press machine tools used in metal manufacturing industry for increasing the safety according to occupation safety [Metal Imalat sektöründe kullanilan preslerin is güvenligi açisindan güvenli hale getirilmesi için tesvik sisteminin kurulmas]
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May solid food refusal and other non-specifi neurological symptoms be an early symptoms of Vitamin B12 defiiency in complementary feeding period?
No full textMethod of Blood Pressure Measurement in Neonates and Infants: A Systematic Review and Analysis
No full textObjectives To determine the recommended blood pressure (BP) measurement
methods in neonates after systematically analyzing the literature
regarding proper BP cuff size and measurement location and method.
Study design A literature search was conducted inMEDLINE, PubMed,
Embase, Cochrane Library, and CINAHL from 1946 to 2017 on BP in neonates
<3 months of age (PROSPERO ID CRD42018092886). Study data were extracted
and analyzed with separate analysis of Bland-Altman studies comparing
measurement methods.
Results Of 3587 nonduplicate publications identified, 34 were
appropriate for inclusion in the analysis. Four studies evaluating BP
cuff size support a recommendation for a cuff width to arm circumference
ratio of approximately 0.5. Studies investigating measurement location
identified the upper arm as the most accurate and least variable
location for oscillometric BP measurement. Analysis of studies using
Bland-Altman methods for comparison of intra-arterial to oscillometric
BP measurement show that the 2 methods correlate best for mean arterial
pressure, whereas systolic BP by the oscillometric method tends to
overestimate intra-arterial systolic BP. Compared with intra-arterial
methods, systolic BP, diastolic BP, and mean arterial pressure by
oscillometric methods are less accurate and precise, especially in
neonates with a mean arterial pressure <30 mm Hg.
Conclusions Proper BP measurement is critical in neonates with naturally
lower BP and attention to BP cuff size, location, and method of
measurement are essential. With decreasing use of intra-arterial
catheters for long-term BP monitoring in neonates, further studies are
urgently needed to validate and develop oscillometric methodology with
enhanced accuracy
Synthesıs And Characterızatıon Of Composıte Electro-Catalyst For Hydrogen Productıon
No full textPEM elektrolizörlerinde hidrojen oluşum reaksiyonu (HOR), hidrokarbonlardan bağımsız enerji üretiminde oldukça önemli olan bir elektrokimyasal tepkimedir. Ancak hidrojen oluşum reaksiyonu için kullanılan platin gibi pahalı soy metaller PEM elektrolizörlerin maliyetini yükseltmektedir. Bunun yanısıra PEM elektrolizörlerde kullanılan elektro-katalizörlerin asidik ortamdaki kararlılığı da önemli bir noktadır. Dolayısıyla bu çalışmada PEM elektrolizörlerde hem Pt oranını düşürebilmek hem de asidik ortamda kararlılığı korumak için alternatif olarak kompozit elektro-katalizörlerin geliştirilmesi düşünülmüştür. Bu bağlamda, düşük Pt yüklemeli ve yüksek Fe ve Ni içerikli seryum kompozit.destekli elektro-katalizörler (Pt/FexCeyOz, Pt/NixCeyOz) emdirme-hidrotermal tekniği ile sentezlenerek farklı indirgenme sıcaklıklarında (400 oC, 600 oC ve 800 oC) ısıl işlemden geçirilmiştir. Elde edilen elektro-katalizörlerin.HOR aktiviteleri, kararlılıkları döngülü voltametri (DV), kronoamperometri (KA) ve elektrokimyasal empedans spektroskopisi (EES) yöntemleri ile analiz edilip kıyaslanmıştır. Döngülü voltametri çalışmalarında.400 oC’de indirgenmiş katalizörler 600 oC ve 800 oC’deki katalizörlere göre daha yüksek elektrokimyasal aktivite sergilemişlerdir. Elektrokimyasal analizler sonunda hidrojen gaz çıkışı açısından en yüksek aktivite ve en düşük faradaik direnç 400 oC’de indirgenmiş Pt/FexCeyOz ile elde edilmiştir. Yapılan elektrokimyasal analizlere genel olarak bakıldığında indirgenme sıcaklığı ve pH düştüğünde yük aktarım direncinin azaldığı gözlenmiş olup indirgenme sıcaklığının yük aktarım direnci üzerinde daha baskın etkisi görülmektedir. Aynı zamanda yapılan fiziksel ve kimyasal analizler sonucunda.FexCeyOz destek yapı üzerinde daha yüksek elektrokimyasal aktivite görülmesinin sebebi, NixCeyOz’ye göre.daha yüksek seryum içeriği ve daha düşük oksijen içeriğine sahip.olmasına ve farklı yüzey morfolojisine bağlanabilirHydrogen Evolution Reaction (HER) in PEM electrolyzers is an important electrochemical reaction which is very important in hydrocarbon-independent energy production. However, expensive noble metals such as platinum used for hydrogen evolution reaction increase the production cost of PEM electrolyzers. In addition, it is also important to maintain the stability of the electrocatalysts in an acidic environment used in these electrolyzers. Therefore in this study, it is aimed to develop alternative composite catalysts in PEM electrolyzers to reduce both the Pt ratio and increase the stability of electrocatalyst in an acidic environment. In this study, low Pt loading and high Fe and Ni content ceria composite supported electrocatalysts (Pt/FexCeyOz, Pt/NixCeyOz) were synthesized by the impregnation-hydrothermal technique and pretreated at different reduction temperatures (400 oC, 600 oC and 800 oC). HER activities of the electrocatalysts were analyzed and compared with cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). During cyclic voltammetry studies, catalysts pretreated at 400 oC showed higher activity than the ones pretreated at 600 oC and 800 oC. Highest HER activity and lowest faradaic resistance were achieved with Pt/FexCeyOz reduced at 400 oC. In general, electrochemical analyses indicate that charge transfer resistance decreases when reduction temperature and pH drop. In addition, reduction temperature has a dominant effect on charge transfer resistance compared to pH. Physical and chemical analyzes also demonstrate that higher electrochemical activity on FexCeyOz support could be related with low oxygen content, high ceria content and surface morpholog
Pullout behavior of geocell reinforcement in cohesionless soils
No full textLarge-scale laboratory equipment was developed to assess interaction
between soil and 3-D honeycomb shaped geocell reinforcement under normal
and interface shear stress. An understanding of this interaction is
vital in assessing mechanical behavior of geocell-reinforced soil mass.
Specifically, the equipment allows evaluation of the load transfer
mechanism with the measurements of strains, displacements and loads,
including friction and passive resistance on the side surfaces and
inside the cells of geocell reinforcement. Additionally, the device
visually presents sequence of movement response of each reinforcing cell
in the direction of the pulling force, thereby showing the contribution
of each cell to the total capacity. Overall, it is concluded that the
pullout capacity of geocell reinforcement in cohesionless soils is
limited to the seam peel strength at junctions of longitudinal and
transverse of geocell strips, which creates the cells in layout of
geocell reinforcement. Finally, a theoretical approach was established
to predict the pullout capacity of geocell-reinforced soil mass
Antioxidant effects of dexmedetomidine against hydrogen peroxide-induced DNA damage in vitro by alkaline Comet assay
No full textBackground/aim: Dexmedetomidine (DEX) is an alpha-2 adrenergic agonist
that is commonly used as a sedative and anesthetic. The protective
effects of DEX against oxidative damage under both in vitro and in vivo
conditions have been demonstrated. It was aimed to evaluate and compare
the protective effects of DEX and vitamin C (Vit C) on DNA against
H2O2-induced DNA damage in human lymphocyte cell cultures in vitro by
alkaline Comet assay.
Materials and methods: Lymphocyte cell cultures were divided into 5
groups, as the negative control, solvent control, positive control,
hydrogen peroxide (H2O2; 150 mu M) + DEX (1 mu M; 2.5 mu M; 5 mu M), and
H2O2 (150 mu M) Vit C (1 mu M; 2.5 mu M; 5 mu M), and incubated at 37
degrees C for 1 h. Cell viability was measured using the Trypan blue
test. DNA damage was measured using the Alkali Comet Technique and the
\% percent tail intensity was evaluated. Statistical analysis was
performed using 1-way ANOVA and the Tukey multiple comparison test.
Results: It was observed that H2O2 significantly induced DNA damage in
the lymphocytes and this damage was decreased significantly with Vit C
and DEX. It was observed that Vit C at doses of 1 mu M and 2.5 mu M had
a significantly stronger antioxidant effect, but there was no
significant difference between the antioxidant effects of Vit C and DEX
with a dose of 5 mu M. The dose of 5 mu M DEX was found to be the most
effective in reducing oxidative DNA damage.
Conclusion: There is limited data on the protective effects of DEX
against oxidative DNA damage. The primary effect might be
cytoprotection. The results herein showed that DEX was protective
against H2O2-induced in vitro oxidative DNA damage in lymphocyte cell
cultures in a dose-dependent manner. DEX might have a potential
therapeutic value in the prevention of oxidative DNA damage in patients
