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Ultra‐structural hair alterations in Friedreich's ataxia: A scanning electron microscopic investigation
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F. Pinar Turkmenoglu U. Baran Kasirga H. Hamdi Celik 《Microscopy research and technique》2015,78(8):731-736
Friedreich's ataxia (FRDA) is an autosomal recessive inherited disorder involving progressive damage to the central and peripheral nervous systems and cardiomyopathy. FRDA is caused by the silencing of the FXN gene and reduced levels of the encoded protein, frataxin. Frataxin is a mitochondrial protein that functions primarily in iron‐sulfur cluster synthesis. Skin disorders including hair abnormalities have previously been reported in patients with mitochondrial disorders. However, to our knowledge, ultra‐structural hair alterations in FRDA were not demonstrated. The purpose of this study was to determine ultra‐structural alterations in the hairs of FRDA patients as well as carriers. Hair specimen from four patients, who are in different stages of the disease, and two carriers were examined by scanning electron microscope. Thin and weak hair follicles with absence of homogeneities on the cuticular surface, local damages of the cuticular layer, cuticular fractures were detected in both carriers and patients, but these alterations were much more prominent in the hair follicles of patients. In addition, erosions on the surface of the cuticle and local deep cavities just under the cuticular level were observed only in patients. Indistinct cuticular pattern, pores on the cuticular surface, and presence of concavities on the hair follicle were also detected in patients in later stages of the disease. According to our results, progression of the disease increased the alterations on hair structure. We suggest that ultra‐structural alterations observed in hair samples might be due to oxidative stress caused by deficient frataxin expression in mitochondria. Microsc. Res. Tech. 78:731–736, 2015. © 2015 Wiley Periodicals, Inc. 相似文献
104.
Silicon - The influence of the Si substitution ratio on the structural, morphological, and optical properties of Cu2ZnSnS4 (CZTS) thin films was examined. The Cu2Zn(SixSn1–x)S4 thin films... 相似文献
105.
The purpose of this study was to examine the effect of different cleaning methods and resin cements on the shear bond strength (SBS) of contaminated zirconia. A total of 92 disc-shaped zirconia specimens were contaminated with different procedures. Then, the specimens were grouped according to cleaning methods and resin cements: no cleaning + Variolink Esthetic DC (CNV), no cleaning + Panavia V5 (CNP), sandblasted + Variolink Esthetic DC (SBV), sandblasted + Panavia V5 (SBP), Ivoclean + Variolink Esthetic DC (ICV), Ivoclean + Panavia V5 (ICP), Katana Cleaner + Variolink Esthetic DC (KCV), and Katana Cleaner + Panavia V5 (KCP). Following an aging protocol in a 37°C for 1 week, SBS analysis was performed with a universal test machine. For the surface topography and elemental analysis, scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS) were used. Significance was evaluated as p < .05 and p < .01. The highest SBS results were found in the SBP group, showing a statistically significant difference from all other groups (p < .05). For the same cleaning method, Panavia V5 showed statistically significantly higher SBS values than Variolink Esthetic DC (p < .01), except the CNP–CNV (p = .880) and KCP–KCV (p = .082) groups. The most detected surface elements by EDS were Zr, O, C, and N, respectively. The contaminated zirconia surfaces must be cleaned for successful adhesion. The use of phosphate-containing adhesives in combination with sandblasting will increase the adhesion strength, and universal cleaning agents can be a good alternative to sandblasting. 相似文献
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Nurcin Celik Sai Srinivas Nageshwaraniyer Young-Jun Son 《Journal of Intelligent Manufacturing》2012,23(4):1083-1101
This paper presents a comprehensive framework for the analysis of the impact of information sharing in hierarchical decision-making in manufacturing supply chains. In this framework, the process plan selection and real-time resource allocation problems are formulated as hierarchical optimization problems, where problems at each level in the hierarchy are solved by separate multi-objective genetic algorithms. The considered multi-objective genetic algorithms generate near optimal solutions for NP-hard problems with less computational complexity. In this work, a four-level hierarchical decision structure is considered, where the decision levels are defined as enterprise level, shop level, cell level, and equipment level. Using this framework, the sources of information affecting the achievement of best possible decisions are then identified at each of these levels, and the extent of their effects from sharing them are analyzed in terms of the axis, degree and the content of information. The generality and validity of the proposed approach have been successfully tested for diverse manufacturing systems generated from a designed experiment. 相似文献
107.
Hasan Celik Akira Nakayama Unver Ozkol 《Numerical Heat Transfer, Part A: Applications》2013,63(7):1368-1386
AbstractVolume averaged thermal transport properties of two metal foams with 10 and 20 PPI are obtained by using microtomography technique. The digital 3D structures of samples are generated in computer environment. The governing equations are solved for the entire domain and the volume averaged technique is used to determine interfacial heat transfer coefficient, longitudinal and transverse thermal dispersion conductivity. The study is performed for the pore scale Reynolds number from 100 to 600. The obtained results are within the ranges of the suggested correlations in literature. The present study supports the correlations suggested by Calmidi and Mahajan (2000) and Zhang et al. (2016). 相似文献
108.
F Uberall K Hellbert S Kampfer K Maly A Villunger M Spitaler J Mwanjewe G Baier-Bitterlich G Baier HH Grunicke 《Canadian Metallurgical Quarterly》1999,144(3):413-425
Liver fatty acid binding protein (L-FABP) appears to contain several different forms that may result from post-translational modification or bound ligand. To further assess this possibility, L-FABP was purified from rat liver homogenate and two putative isoforms separated using a sulfonyl column, a strong cation exchange resin. Fraction I eluted at 0.2 M NaCl, had a pI of 7.59, and following a final size exclusion step contained > 98% L-FABP. Fraction II eluted at 1.0 M NaCl, had a pI of 7.59, and following a final size exclusion step contained > 99% L-FABP. Both fractions contained approx. 0.15 moles of endogenous bound fatty acid per mole of protein, while L-FABP not subjected to the cation exchange step contained 0.75 moles of fatty acid per mole of protein. Fractions I and II had a greater proportion of saturated and monounsaturated fatty acids with a large reduction in polyunsaturated fatty acids compared to L-FABP not fractionated by cation exchange. Mass spectral analysis indicated the molecular mass of Fraction I was 14,315.02 +/- 0.35 Da and Fraction II was 14,315.86 +/- 0.34 Da. The peptide map for each fraction was determined by limited digestion of each fraction with either trypsin, Asp-N, or chymotrypsin to yield overlapping peptide fragments. Mass spectral analysis of these digests indicated the two proteins had identical amino acid fragments and that Cys69 was reduced and there were no Asn to Asp exchanges. Hence, these two forms of L-FABP were not isoforms and were not the result of differences in bound fatty acid. It is proposed that these two distinct forms of rat L-FABP were structural conformers based on two alternative folding pathways. 相似文献
109.
Material selection, one of the mostly encountered decision problems in material science literature, is still an onerous task for manufacturing organisations. Achieving accurate solution to this issue, the paper developed a model selection interface to enable analytical solutions to different problem concepts in material selection under multiple attribute decision-making (MADM) environments. Specifically, the generic framework of the fuzzy axiomatic design-model selection interface (FAD-MSI) is modified and successfully applied to the different material selection problem concepts. Consequently, the derived problem-model sets can be referred to accomplish further proposals on this era. 相似文献
110.
Breeding animal transports between parts of our institute were used assessing effects of age of animals, of breed, of their functional state and of individual specificity of reaction patterns using peripheral venous blood samples. Increased mean values of Hb, Hk, body temperature, total protein, albumin, FT4, T4, FT3, T3, cortisol, adrenaline and decreased ones of body weight, Pa, Fe, noradrenaline were found after transport stress. Comparing age matched groups of DSB and HF breed higher concentrations of total protein, creatinine, lactate, cortisol, FT4, T3 and FT3 and lower ones of albumin, blood urea and Fe could be observed in animals of DSB breed before and after transport. Strong correlations existed on 14 variables within animals before and after transport stress meaning there could be individual specificity of some blood parameters. 相似文献