Medical genetics and genomic medicine in Turkey: a bright future at a new era in life sciences

[No abstract available

Drastic microstructural modification of Bi2Ca2Co2Oy ceramics by Na doping and laser texturing

Bi2Ca2-xNaxCo2Oy materials with x = 0 = x = 0.125, have been prepared either by sintering through the classical ceramic method, or textured using the laser floating zone technique. XRD results have shown that Bi2Ca2Co2Oy phase is the major one, independently of the Na content, in both kind of samples. SEM studies have shown a drastic microstructural modification between sintered and laser-textured materials. Na-doping increases density and grain sizes in sintered materials, while it enhances grain alignment in laser-grown materials. Moreover, it decreases secondary phase content in all cases. Electrical resistivity is also drastically reduced through texturing, when compared to the sintered samples, and Na-doping further decreases it. The lowest values determined in the laser-textured samples (26 mO cm at 650 °C) are around 40% lower than the best in sintered materials. On the other hand, S has been only slightly affected for Na-doping or processing method for all samples. Consequently, the highest power factor at 650 °C (0.18 mW/K2 m) has been obtained in laser-grown 0.075Na-doped samples, which is around 20 and 70% higher than the measured in undoped laser-textured samples, and sintered ones, respectively. Se han preparado materiales de composición Bi2Ca2-xNaxCo2Oy, con x = 0 ≤ x ≤ 0,125, por el método de estado sólido, además de texturarlos mediante la técnica de zona flotante inducida por láser. Los resultados de XRD han mostrado que la fase Bi2Ca2Co2Oy aparece como la mayoriraria, independientemente del contenido de Na, en ambos tipos de muestras. Los estudios SEM han encontrado una drástica modificación microestructural entre materiales sinterizados y texturados. El dopado con Na aumenta la densidad y el tamaño de grano en materiales sinterizados, mientras que mejora la orientación de los granos en materiales texturados. Además, disminuye el contenido de fases secundarias en todos los casos. La resistividad eléctrica disminuye drásticamente con el texturado, en comparación con las muestras sinterizadas, mientras que el dopado con Na la disminuye aún más. Los valores más bajos determinados en muestras texturadas (26 mΩ cm a 650 °C) son alrededor del 40% menor que los mejores datos publicados en materiales sinterizados. Por otro lado, S solo se ha visto afectado levemente, tanto por el dopado como por el método de procesado. En consecuencia, el máximo factor de potencia a 650 °C (0,18 mW/K2 m) se ha obtenido en muestras dopadas con 0,075 Na y texturadas, que es alrededor de un 20 a un 70% superior al medido en muestras texturadas sin dopar y sinterizadas, respectivamente

DNA repair gene polymorphisms and bladder cancer susceptibility in a Turkish population

Background: Occupational exposure and life style preferences, such as smoking are the main known environmental susceptibility factors for bladder cancer. A growing list of chemicals has been shown to induce oxidative DNA damage. Base excision repair (BER) genes (X-ray repair cross complementing 1, XRCC1 and human 8-oxoguanine DNA glycosylase 1, OGG1) may play a key role in maintaining genome integrity and preventing cancer development. Materials and Methods: We tested whether polymorphisms in XRCC1 and OGG1 are associated with bladder cancer risk by using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) assay. In addition, the possible modifying affect of cigarette smoking was evaluated. Results: No studies, to date, have examined the association between genetic polymorphisms in DNA repair genes and bladder cancer susceptibility, in the Turkish population. We found the OGG1 Cys326Cys genotype to be more frequent among bladder cancer patients (odds ratio (OR): 2.41 (95% CI, 1.36-4.25)). However, in the case of XRCC1, there was no significant difference in susceptibility to bladder cancer development between patients with the Arg399 and these with the Gln399 allele (OR: 0.72 (95% CI, 0.41-1.26)). Conclusion: Our data showed that OGG1 genetic polymorphisms might be useful as prognostic genetic markers for bladder cancer in the clinical setting

MDM2 T309G polymorphism is associated with bladder cancer

Recently, a functional T to G polymorphism at nucleotide 309 in the promoter region of the MDM2 gene (rs: 2279744, SNP 309) has been identified. This polymorphism has an impact on the expression of the MDM2 gene, which is a key negative regulator of the tumor suppressor molecule p53. The effect of T309G polymorphism of the MDM2 gene on bladder cancer susceptibility was investigated in a case-control study of 75 bladder cancer patients and 103 controls from Turkey. The G/G genotype exhibited an increased risk of 2.68 (95% CI, 1.34-5.40) for bladder cancer compared with the combination of low-risk genotypes T/T and T/G at this locus. These results show an association between MDM2 T309G polymorphism and bladder cancer in our study group. To the best of our knowledge, this is the first study reporting that MDM2 T309G polymorphism may be a potential genetic susceptibility factor for bladder cancer

Analysis of MYH Tyr165Cys and Gly382Asp variants in childhood leukemias

[No abstract available

Turkish population data on the HLA-DQα, LDLR, GYPA, HBGG, D7S8, and GC loci

We have determined the allele and genotype frequencies of six PCR-based genetic markers HLA-DQα, LDLR, GYPA, HBGG, D7S8 and GC in the Turkish population (n = 361 for HLA-DQα, and n = 260 for PM). All loci meet Hardy- Weinberg expectations. The frequency data can be used in forensic analyses in the Turkish population

Buffer effects on the mosaic structure of the HR-GaN grown on 6H-SiC substrate by MOCVD

High-resistive GaN (>108 Ω cm) layers have been grown with different buffer structures on 6H-SiC substrate using metalorganic chemical vapor deposition reactor. Different combination of the GaN/AlN super lattice, low temperature AlN, high temperature AlN and AlxGa1−xN (x ≈ 0.67) layers were used in the buffer structures. The growth parameters of the buffer layers were optimized for obtaining a high-resistive GaN epilayer. The mosaic structure parameters, such as lateral and vertical coherence lengths, tilt and twist angle (and heterogeneous strain), and dislocation densities (edge and screw dislocations) of the high-resistive GaN epilayers have been investigated using x-ray diffraction measurements. In addition, the residual stress behaviors in the high-resistive GaN epilayers were determined using both x-ray diffraction and Raman measurements. It was found that the buffer structures between the HR-GaN and SiC substrate have been found to have significant effect on the surface morphology and the mosaic structures parameters. On the other hand, both XRD and Raman results confirmed that there is low residual stress in the high-resistive GaN epilayers grown on different buffer structures. © 2016, Springer Science+Business Media New York

Properties of Solutions in 2+1 Dimensions

We solve the Einstein equations for the 2+1 dimensions with and without scalar fields. We calculate the entropy, Hawking temperature and the emission probabilities for these cases. We also compute the Newman-Penrose coefficients for different solutions and compare them.Comment: 16 pages, 1 figures, PlainTeX, Dedicated to Prof. Yavuz Nutku on his 60th birthday. References adde

The SOCS-1 gene methylation in chronic myeloid leukemia patients

SOCS-1, an important protein in the JAK/STAT pathway, has a role in the down stream of BCR-ABL protein kinase. We investigated 56 CML patients and 16 controls for the methylation status of SOCS-1 gene promoter and Exon 2 regions. Exon 2 was found to be methylated in 58.9% of the patients and 93.8% of the controls [P = 0.020, OR = 0.121(0.015-0.957)%95CI]. The promoter region was found unmethylated in all patient samples and controls. Although previous studies revealed a relation between SOCS1 gene Exon-2 hypermethylation and CML development or progression, the results of this study showed no such correlation. On the contrary, our results might be indicating hypomethylation in CML patients, this hypothesis need to be studied in larger study population. © 2007 Wiley-Liss, Inc

Mutation of the Human Circadian Clock Gene CRY1 in Familial Delayed Sleep Phase Disorder

Patterns of daily human activity are controlled by an intrinsic circadian clock that promotes ∼24 hr rhythms in many behavioral and physiological processes. This system is altered in delayed sleep phase disorder (DSPD), a common form of insomnia in which sleep episodes are shifted to later times misaligned with the societal norm. Here, we report a hereditary form of DSPD associated with a dominant coding variation in the core circadian clock gene CRY1, which creates a transcriptional inhibitor with enhanced affinity for circadian activator proteins Clock and Bmal1. This gain-of-function CRY1 variant causes reduced expression of key transcriptional targets and lengthens the period of circadian molecular rhythms, providing a mechanistic link to DSPD symptoms. The allele has a frequency of up to 0.6%, and reverse phenotyping of unrelated families corroborates late and/or fragmented sleep patterns in carriers, suggesting that it affects sleep behavior in a sizeable portion of the human population. © 2017 Elsevier Inc