Brain lipid profiling of triply mouse model with the deficiencies of sialidase neu1, neu4 and β-hexosaminidase a enzymes

Thesis (Master)--Izmir Institute of Technology, Molecular Biology and Genetics, Izmir, 2011Includes bibliographical references (leaves: 41-61)Text in English; Abstract: Turkish and Englishxi, 61 leavesTay-Sachs disease is a severe lysosomal storage disorder caused by mutations in the HEXA gene coding for α subunit of lysosomal β-hexosaminidase A enzyme, which converts GM2 to GM3 ganglioside. HexA-/- mice, depleted of β-hexosaminidase A enzyme, remain asymptomatic to 1 year of age, so it was thought there is a difference between human and mice lipid degradation. Previously identified a novel ganglioside metabolizing sialidase, Neu4, is abundantly expressed in mouse brain neurons. It was demonstrated that mice with targeted disruption of both HexA and Neu4 genes (HexA-/- Neu4-/-) show accumulating GM2 ganglioside and epileptic seizures with 40% penetrance. Since all mice didn't show symptoms, it was suggested that Neu4 is not the only sialidase contributing to the metabolic bypass in HexA-/- mice (Seyrantepe et al. 2010). Therefore, we studied the role of another sialidase Neu 1 in glycolipid degradation. We profiled brain glycolipid content of triple deficient mouse model with the deficiency of β-hexosaminidase A (0% activity), sialidase Neu4 (0% activity) and sialidase Neu 1 (10% activity) (NeoIn) by thin layer chromatography. Analysis of both double (HexA-/-NeoIn-/-) and triple (HexA-/-Neu4-/-NeoIn-/-) mice models showed that sialidase Neu 1 deficency causes not significant difference in brain lipid profile and though also other sialidase/sialidases might have role in glycolipid degradation pathway in mice

An analysis of the changes in food consumption frequencies before and during the COVID-19 pandemic: Turkey

Caused by the SARS-CoV-2, the COVID-19 outbreak that has turned into a global pandemic has proved that many events that would have been deemed as elements of pure fiction can indeed become reality. Millions of people in many countries isolated/are isolating themselves within the scope of self-quarantine to control the outbreak. This might affect one's dietary habits either positively or negatively. One of the first in its field, the present study statistically examines the changes in food consumption frequencies of 3017 individuals living in one of the seven regions of Turkey before and during the COVID-19 pandemic using a scale formulated with this specific purpose. As far as food consumption frequencies are concerned, while no statistically significant differences were spotted in the general total of the scale, 9 out of 10 sub-groups, the exception being the bread group, manifested statistically significant variations (p<0.001). Specifically, while the consumption of dietary supplements like propolis or vitamins C and D surged, the consumption of flour, sugar, salt, and various beverages (instant coffee, soft drinks) fell significantly. The post-COVID-19 era is considered to bring about an increase in the demand for products boosting the immune system

A guide for more accurate and precise estimations in simulative unidimensional IRT models

There is a great deal of research about item response theory (IRT) conducted by simulations. Item and ability parameters are estimated with varying numbers of replications under different test conditions. However, it is not clear what the appropriate number of replications should be. The aim of the current study is to develop guidelines for the adequate number of replications in conducting Monte Carlo simulation studies involving unidimensional IRT models. For this aim, 192 simulation conditions which included four sample sizes, two test lengths, eight replication numbers, and unidimensional IRT models were generated. Accuracy and precision of item and ability parameter estimations and model fit values were evaluated by considering the number of replications. In this context, for the item and ability parameters; mean error, root mean square error, standard error of estimates, and for model fit; M-2, RMSEA(2), and Type I error rates were considered. The number of replications did not seem to influence the model fit, it was decisive in Type I error inflation and error prediction accuracy for all IRT models. It was concluded that to get more accurate results, the number of replications should be at least 625 in terms of accuracy of the Type I error rate estimation for all IRT models. Also, 156 replications and above can be recommended. Item parameter biases were examined, and the largest bias values were obtained from the 3PL model. It can be concluded that the increase in the number of parameters estimated by the model resulted in more biased estimates

Influence of the C/O ratio on titanium and vanadium oxides in protoplanetary disks

Context. The observation of carbon-rich disks have motivated several studies questioning the influence of the C/O ratio on their gas phase composition in order to establish the connection between the metallicity of hot-Jupiters and that of their parent stars. Aims. We to propose a method that allows the characterization of the adopted C/O ratio in protoplanetary disks independently from the determination of the host star composition. Titanium and vanadium chemistries are investigated because they are strong optical absorbers and also because their oxides are known to be sensitive to the C/O ratio in some exoplanet atmospheres. Methods. We use a commercial package based on the Gibbs energy minimization technique to compute the titanium and vanadium equilibrium chemistries in protoplanetary disks for C/O ratios ranging from 0.05 to 10. Our calculations are performed for pressures ranging from 1e-6 to 1e-2 bar, and for temperatures ranging from 50 to 2000 K. Results. We find that the vanadium nitride/vanadium oxide and titanium hydride/titanium oxide gas phase ratios strongly depend on the C/O ratio in the hot parts of disks (T > 1000 K). Our calculations suggest that, in these regions, these ratios can be used as tracers of the C/O value in protoplanetary disks.Comment: Accepted for publication in A&

Green tea extract exerts anabolic effects on extracellular matrix of the skin

An in vitro trial was carried out to reveal the effects of an extract of Camellia sinensis (green tea extract) on the major extracellular matrix components of human skin. After preparing the green tea extract its phytochemical contents were analysed and its effects on gene expression of hyaluronan synthase 2, matrix metalloproteinase-9 and elastase in a human dermal fibroblast cell line were determined. Cell proliferation assay was performed using XTT reagent. Ribonucleic acid isolations were realized by using TRI reagent. Expressions of the relevant enzymes and a control enzyme glyceraldehyde-3-phosphate dehydrogenase were determined using RT-qPCR analysis. Green tea extract caused statistically significant upregulation of hyaluronan synthase-2 gene expression compared to untreated control cells. Also, as a positive outcome, the treatment resulted in significant downregulations of matrix metalloproteinase-9 and elastase gene expressions. Green tea extract was found to have substantial anabolic effects on hyaluronic acid, collagen and elastin. The results obtained in this study might partially explain the molecular basis of the health benefits and antiaging effects of Camellia sinensis on skin

Modeling the officer recruitment and manpower planning process in Turkish land forces

Cataloged from PDF version of article.The objective of this study is to improve the Turkish Land Forces officer accessions and manpower planning process. A model for planning officer accessions to Turkish Land Forces from sources that have different characteristics is presented. This model takes into account factors such as attritions, involuntary retirements, promotions and transitions to determine the impact of existing policies over the long term and to determine adjustments that might be required to reach authorized strength goals. The annual supply of accessions necessary to meet the strength goal with minimum deviations is determined. This manpower planning model is created using the modeling software GAMS.Pekmezci, ArzM.S