40 research outputs found
All-chalcogenide glass omnidirectional photonic band gap variable infrared filters
Cataloged from PDF version of article.We report on the design, fabrication, and characterization of spatially variable infrared photonic band gap filter that consists of thermally evaporated, high refractive index contrast, amorphous chalcogenide glass multilayers. Due to graded thickness structure, the filter exhibits a position dependent stop band and a cavity mode ranging from 1.8 to 3.4 μm wavelengths. Reflection measurements on the variable filter agree well with theoretical calculations. These results pave the way to low-loss infrared mirrors, filters, spectral imaging, and miniaturized spectrometers at infrared region. © 2009 American Institute of Physics
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Hydrogen Fuel Cell Analysis: Lessons Learned from Stationary Power Generation Final Report
This study considered opportunities for hydrogen in stationary applications in order to make recommendations related to RD&D strategies that incorporate lessons learned and best practices from relevant national and international stationary power efforts, as well as cost and environmental modeling of pathways. The study analyzed the different strategies utilized in power generation systems and identified the different challenges and opportunities for producing and using hydrogen as an energy carrier. Specific objectives included both a synopsis/critical analysis of lessons learned from previous stationary power programs and recommendations for a strategy for hydrogen infrastructure deployment. This strategy incorporates all hydrogen pathways and a combination of distributed power generating stations, and provides an overview of stationary power markets, benefits of hydrogen-based stationary power systems, and competitive and technological challenges. The motivation for this project was to identify the lessons learned from prior stationary power programs, including the most significant obstacles, how these obstacles have been approached, outcomes of the programs, and how this information can be used by the Hydrogen, Fuel Cells & Infrastructure Technologies Program to meet program objectives primarily related to hydrogen pathway technologies (production, storage, and delivery) and implementation of fuel cell technologies for distributed stationary power. In addition, the lessons learned address environmental and safety concerns, including codes and standards, and education of key stakeholders
Oxidative stress in hepatitis C infected end-stage renal disease subjects
BACKGROUND: Both uremia and hepatitis C infection is associated with increased oxidative stress. In the present study, we aimed to find out whether hepatitis C infection has any impact on oxidative stress in hemodialysis subjects. METHODS: Sixteen hepatitis C (+) hemodialysis subjects, 24 hepatitis C negative hemodialysis subjects and 24 healthy subjects were included. Total antioxidant capacity, total peroxide level and oxidative stress index were determined in all subjects. RESULTS: Total antioxidant capacity was significantly higher in controls than hemodialysis subjects with or without hepatitis C infection (all p < 0.05/3), while total peroxide level and oxidative stress index were significantly lower (all p < 0.05/3). Hepatitis C (-) hemodialysis subjects had higher total antioxidant capacity compared to hepatitis C (+) hemodialysis subjects (all p < 0.05/3). Total peroxide level and oxidative stress index was comparable between hemodialysis subjects with or without hepatitis C infection (p > 0.05/3). CONCLUSION: Oxidative stress is increased in both hepatitis C (+) and hepatitis C (-) hemodialysis subjects. However, hepatitis C infection seems to not cause any additional increase in oxidative stress in hemodialysis subjects and it may be partly due to protective effect of dialysis treatment on hepatitis C infection
Neuropeptidomics of the Supraoptic Rat Nucleus
The mammalian supraoptic nucleus (SON) is a neuroendocrine center in the brain regulating a variety of physiological functions. Within the SON, peptidergic magnocellular neurons that project to the neurohypophysis (posterior pituitary) are involved in controlling osmotic balance, lactation, and parturition, partly through secretion of signaling peptides such as oxytocin and vasopressin into the blood. An improved understanding of SON activity and function requires identification and characteriza-tion of the peptides used by the SON. Here, small-volume sample preparation approaches are optimized for neuropeptidomic studies of isolated SON samples ranging from entire nuclei down to single magnocellular neurons. Unlike most previous mammalian peptidome studies, tissues are not im-mediately heated or microwaved. SON samples are obtained from ex vivo brain slice preparations via tissue punch and the samples processed through sequential steps of peptide extraction. Analyses of the samples via liquid chromatography mass spectrometry and tandem mass spectrometry result in the identification of 85 peptides, including 20 unique peptides from known prohormones. As the sample size is further reduced, the depth of peptide coverage decreases; however, even from individually isolated magnocellular neuroendocrine cells, vasopressin and several other peptides are detected
Validation of a new LC-MS/MS method for serum/saliva cortisol measurement and comparison with commercial ELISA/CLIA methods
23rd IFCC-EFLM European Congress of Clinical Chemistry and Laboratory Medicine (EuroMedLab) -- MAY 19-23, 2019 -- Barcelona, SPAINSezer, Ebru/0000-0002-6900-3539; Tuzcu, Fulya/0000-0002-1528-1090WOS: 000529532100133[No abstract available]Int Federat Clin Chem & Lab Med, European Federat Clin Chem & Lab Me
Validation of a new LC-MS/MS method for serum/saliva cortisol measurement and comparison with commercial ELISA/CLIA methods
The role of BDNF and HPA axis in the neurobiology of burnout syndrome
PubMed ID: 18541357Chronic stress is known to affect the HPA axis. The few clinical studies which have been conducted on HPA-axis function in burnout have produced inconsistent results. The etiological relationship between sBDNF and burnout has not yet been studied. The aim of the current study was to investigate the role of BDNF and HPA axis in the neurobiology of burnout. In the current study 37 clinically diagnosed burnout participants were compared with 35 healthy controls in terms of BDNF, HPA axis, burnout symptoms, depression, anxiety and psychosomatic complaints. Basal serum cortisol, sBDNF and cortisol level after 1 mg DST was sampled. We found no significant differences in terms of HPA-axis function (for basal serum cortisol, p = 0.592; for cortisol level after 1 mg DST, p = 0.921), but we did find lowered sBDNF levels in burnout group (88.66 ± 18.15 pg/ml) as compared to healthy controls (102.18 ± 20.92 pg/ml) and the difference was statistically significant (p = 0.005). Logistic Regression Analysis revealed that emotional exhaustion (p = 0.05), depersonalization (p = 0.005) and depression (p = 0.025) were significantly associated with burnout. sBDNF levels correlated negatively with emotional exhaustion (r = -,268, p = 0.026), depersonalization (r = -,333, p = 0.005) and correlated positively with competence (r = 0.293, p = 0.015) sub-scales of burnout inventory. However, there were no significant relationships between cortisol levels and sBDNF levels (r = 0.80, p = 0.51), depression, anxiety, psychosomatic complaints and burnout inventory. Our results suggest that low BDNF might contribute to the neurobiology of burnout syndrome and it seems to be associated with burnout symptoms including altered mood and cognitive functions. © 2008 Elsevier Inc. All rights reserved.We thank Ass. Prof. Dr. Mehmet Orman, of Ege University School of Medicine, Department of Biostatistics, who kindly supervised and carried out the statistical analysis. This study was supported by a grant from the Psychiatric Association of Turkey (research project support award, 2006). Also an additional financial support has been provided by Wyeth Pharmaceuticals, Turkey. Financial supporters had no further role in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication. -
Gene expression of pro-opiomelanocortin and melanocortin receptors is regulated in the hypothalamus and mesocorticolimbic system following nicotine administration
WOS: 000392790300013PubMed ID: 27890744Pro-opiomelanocortin (POMC)-derived peptides and their receptors have been shown to play important roles in natural and drug-induced reward and reinforcement. Reward process may involve the regulation of POMC gene expression and the gene expression of POMC-derived peptide receptors. The present study investigated the alterations observed in the transcript levels of POMC, melanocortin 3 (MC3R), melanocortin 4 (MC4R) and mu-opioid receptors (MOR) in the hypothalamus and mesocorticolimbic system during nicotine exposure. Rats were injected subcutaneously for 5 days with one of the three doses (0.2, 0.4 or 0.6 mg/kg/day, free base) of nicotine and were decapitated one hour after a challenge dose on the sixth day. mRNA levels of POMC in the hypothalamus, MC3R in the ventral tegmental area (VTA), MC4R and MOR in the medial prefrontal cortex (mPFC), nucleus accumbens, dorsal striatum, amygdala, lateral hypothalamic area and VTA were measured by quantitative real-time PCR. Our results showed that treatment with 0.6 mg/kg/day nicotine upregulated POMC mRNA in the hypothalamus and MC4R mRNA in the mPFC. Additionally, all three nicotine doses increased MC3R mRNA expression in the VTA. On the other hand, none of the nicotine doses altered MOR mRNA levels in the mesocorticolimbic system and associated limbic structures. These results suggest that nicotine may enhance melanocortin signaling in the mesocorticolimbic system and this alteration may be an important mechanism mediating nicotine reward. (C). 2016 Elsevier Ireland Ltd. All rights reserved.Ege University Scientific Research Projects CommissionEge University [2015-BAUM-002]This work was supported financially by Ege University Scientific Research Projects Commission (Research Fund Grant 2015-BAUM-002). The funding source had no involvement in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication