Análisis cariotípico de Minuartia mesogitana subsp. mesogitana y Minuartia elmalia (Caryophyllaceae, Alsinoideae).

Mitotic metaphase chromosomes, karyotypic characters, monoploid karyograms and ideograms of Minuartia mesogitana subsp. mesogitana and Minuartia elmalia were investigated. Analysis of somatic metaphases showed that the chromosome numbers and the karyotype formula of these taxa were 2n = 2x = 24 = 8m + 8sm + 8st for Minuartia mesogitana subsp. mesogitana and 2n = 2x = 32 = 12m + 16sm + 4st for Minuartia elmalia. No satellites were observed in the karyotypes of the taxa. The intrachromosomal and interchromosomal karyotype asymmetries were estimated with Mean Centromeric Asymmetry (MCA) and Coefficient of Variation of Chromosome Length (CVCL).Análisis cariotípico de Minuartia mesogitana subsp. mesogitana y Minuartia elmalia (Caryophyllaceae, Alsinoideae). En este trabajo se analizan los cromosomas metafásicos mitóticos, cariotipo, cariogramas e idiogramas de Minuartia mesogitana subsp. Mesogitana y Minuartia elmalia. El análisis de metafases somáticas mostró que el número cromosómico y la fórmula cariotípica de estos taxones fueron 2n = 2x = 24 = 8 m + 8 sm + 8 st para Minuartia subsp. Mesogitana y 2n = 2x = 32 = 12 m + 16 sm + 4 st para Minuartia elmalia. No se observaron satélites en los cariotipos de los taxones. La asimetría intracromosómica e intercromosómica fue estimada con la asimetría centroméricas promedio (MCA) y el coeficiente de variación de longitud cromosómica (CVCL)

The conserved C-terminus of the PcrA/UvrD helicase interacts directly with RNA polymerase

Copyright: © 2013 Gwynn et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by a Wellcome Trust project grant to MD (Reference: 077368), an ERC starting grant to MD (Acronym: SM-DNA-REPAIR) and a BBSRC project grant to PM, NS and MD (Reference: BB/I003142/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

C9orf72 Expansion Disrupts ATM-mediated Chromosomal Break Repair

A hexanucleotide repeat expansion represents the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia, though the mechanisms by which the expansion cause neurodegeneration are poorly understood. We report elevated levels of DNA/RNA hybrids (R-loops) and double-strand breaks (DSBs) in rodent neurons, human cells, and in C9orf72-ALS patient spinal cord tissues. Accumulation of endogenous DNA damage is concomitant with defective ATM-mediated DNA repair signalling and accumulation of protein-linked DNA breaks. We further reveal that defective ATM-mediated DNA repair is a consequence of p62 accumulation, which impairs H2A ubiquitylation and perturbs ATM signalling. Adeno-associated virus- mediated expression of C9orf72-related RNA and dipeptide repeats in the murine central nervous system causes elevated DSBs, ATM defects, and triggers neurodegeneration. These findings identify R-Loops, DSBs, and defective ATM-mediated repair as pathological consequences of C9orf72 expansions, and suggest that C9orf72-linked neurodegeneration is driven, at least in part, by genomic instability

Seasonal variation of suspended particulate matter in two-layered Izmit Bay, Turkey

The spatial and temporal distribution of suspended particulate matter (SPM) concentration in Izmit Bay (Sea of Marmara) were studied in order to examine the prevailing transport mechanisms under varying seasonal hydrographical conditions. The prevailing current system of the Bay occurs in two opposite directions and changes seasonally, flowing into the Bay as a lower layer and flowing out to the Sea of Marmara as an upper layer in autumn and winter. SPM concentrations and distribution pattern of both upper and lower water layers display variations throughout the year, reflecting a seasonal cycle and variability of the circulation and stratification of two water layers seems to control the vertical and spatial distribution of SPM in Izmit Bay. The SPM concentration of the lower layer is higher than that of the upper layer with an increase in intensity of the pycnocline in summer. Homogeneous vertical distribution of SPM during February and March is supported by the weak stratification of the two layers. SPM transportation from Izmit Bay to the open sea occurs in winter, whereas it is carried to interior of the Bay from central to eastern basins in summer. Both the grain size distribution of the bottom sediments and the temporal-spatial variation of SPM content of the water column indicate that the transportation and depositional conditions are different in the three basins. Predominantly fine-grained-sized bottom sediments are deposited in the central and eastern basins due to the reduced current velocities in the lower layer. The western basin is subjected to deposition of sediments with various size, from both the central basin and the Sea of Marmara. (C) 1999 Academic Press

Design and implementation of a personal computer authorization system using color detection

For using of personal computers (PCs) only by authorized persons, there are several methods such as fingerprint or face recognition at logon. In this study, an authorization method based on color detection and coding is designed and implemented. The color on specific coordinate of a color coded card is detected by color sensor with high resolution and converted to RGB code. Then, this code is compared by the RGB codes on a color code database to check the matches. Designed system can also be used cost-efficiently and to be preferable for PCs as in computer laboratories which users are often changed, as PCs in computer laboratories or offices. It also can be adapted to other security systems, and it is low cost. Ill. 5, bibl. 10, tabl. 1 (in English; abstracts in English and Lithuanian)

Design and analysis of internal gears with different rim thickness and shapes

Bu çalışma, 13-19, Kasım 2015 tarihlerinde Houston[Amerika]’da düzenlenen ASME International Mechanical Engineering Congress and Exposition (IMECE2015) Kongresi‘nde bildiri olarak sunulmuştur.In recent years, thanks to their significant advantages such as compactness, large torque-to-weight ratio, large transmission ratios, reduced noise and vibrations, internal gears have been used in automotive and aerospace applications especially in planetary gear drives. Although internal gears have a number of advantages, they have not been studied sufficiently. Internal gears are manufactured by pinion type cutters which are nearly identical with pinion gear except the addendum factor which is 1.25 instead of 1. The tip geometry of a pinion type cutter which determines the fillet of internal gear tooth can be sharp or rounded. In this study, the design of internal gears were investigated by using a traditional approach. Mathematical equations of pinion type cutter were obtained by using differential geometry, then the equations of internal gear tooth were derived accurately by using coordinate transformations and relative motion between the pinion type cutter and internal gear blank. A computer program was generated to attain points of internal gear teeth and three dimensional design of complete gear. 20-20 were used as pressure angle. To find optimum internal gear geometry, different rim thicknesses and shapes are tried out for finite element analyses. There were several parameters that were shown to effect the performance of the internal gears, with tooth stiffness being the most significant parameter. Tooth stiffness was also vitally influence the dynamic analysis. In order to compute gear tooth stiffness of the internal gear with various rim thicknesses and shapes, finite element analysis was used. A static analysis was performed to assess the gear bending stress and tooth displacement. Tetrahedral element type was selected for meshing. The internal gear outer ring was fixed and the force of 2500 N was applied on the tooth. According to the displacement values from the analysis internal gear tooth stiffness were calculated individually. Additionally, the effect of root bending stress with varying rim thickness, shapes, and root radius were investigated. The bending stresses were calculated according to ISO 6336 and using finite element analysis were shown to be in good agreement. It was shown that when the rim thickness and fillet radius were increased, the maximum bending stresses decreased considerably. As rim thickness was increased, the maximum bending stress decreased nearly 23%. It was also shown that as the fillet radius decreased, the maximum bending stress increased, whereas the rim stresses slightly changed. As the fillet radius was decreased, the maximum bending stress increased nearly 10%. It was also observed that when rim thickness was increased, the stress on the rim was decreased, whereas tooth stiffness was increased. However, fillet radius had no visible effect both on rim stress and tooth stiffness. Furthermore, it was shown that the rim shape had significant effect on rim stress.ASM