Multi Micro-Channel-Plate Photomultiplier tubes (MCP-PMT) with High Collection Efficiency (Hi-CE) MCPs are developed and characterised. With these Hi-CE MCPs more than 90% of photoelectrons emitted ...from the photocathode can be detected; this is in contrast to conventional MCPs where about 50% of photoelectrons are lost at the MCP stage. The drawback of the Hi-CE MCPs is a small degradation of the transfer time spread (TTS). However for applications where no sub-ns time resolution is required the implementation of Hi-CE MCPs is extremely beneficial, as it improves the detection efficiency of the MCP-PMT almost by a factor of two.
Nonalcoholic fatty liver disease (NAFLD) can be seen as a manifestation of overnutrition. The muscle is a central player in the adaptation to energy overload, and there is an association between ...fatty-muscle and -liver. We aimed to correlate muscle morphology, mitochondrial function and insulin signaling with NAFLD severity in morbid obese patients.
Liver and deltoid muscle biopsies were collected during bariatric surgery in NAFLD patients. NAFLD Activity Score and Younossi's classification for nonalcoholic steatohepatitis (NASH) were applied to liver histology. Muscle evaluation included morphology studies, respiratory chain complex I to IV enzyme assays, and analysis of the insulin signaling cascade. A healthy lean control group was included for muscle morphology and mitochondrial function analyses.
Fifty one NAFLD patients were included of whom 43% had NASH. Intramyocellular lipids (IMCL) were associated with the presence of NASH (OR 12.5, p<0.001), progressive hepatic inflammation (p = 0.029) and fibrosis severity (p = 0.010). There was a trend to an association between IMCL and decreased Akt phosphorylation (p = 0.059), despite no association with insulin resistance. In turn, hepatic steatosis (p = 0.015) and inflammation (p = 0.013) were associated with decreased Akt phosphoryation. Citrate synthase activity was lower in obese patients (p = 0.047) whereas complex I (p = 0.040) and III (p = 0.036) activities were higher, compared with controls. Finally, in obese patients, complex I activity increased with progressive steatosis (p = 0.049) and with a trend with fibrosis severity (p = 0.056).
In morbid obese patients, presence of IMCL associates with NASH and advanced fibrosis. Muscle mitochondrial dysfunction does not appear to be a major driving force contributing to muscle fat accumulation, insulin resistance or liver disease. Importantly, insulin resistance in muscle might occur at a late point in the insulin signaling cascade and be associated with IMCL and NAFLD severity.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background & Aims Non-alcoholic fatty liver disease (NAFLD) comprises a spectrum of stages from simple steatosis to non-alcoholic steatohepatitis (NASH). However, disease pathogenesis remains largely ...unknown. microRNA (miRNA or miR) expression has recently been reported to be altered in human NASH, and modulated by ursodeoxycholic acid (UDCA) in the rat liver. Here, we aimed at evaluating the miR-34a/Sirtuin 1(SIRT1)/p53 pro-apoptotic pathway in human NAFLD, and to elucidate its function and modulation by UDCA in the rat liver and primary rat hepatocytes. Methods Liver biopsies were obtained from NAFLD morbid obese patients undergoing bariatric surgery. Rat livers were collected from animals fed a 0.4% UDCA diets. Primary rat hepatocytes were incubated with bile acids or free fatty acids (FFAs) and transfected with a specific miRNA-34a precursor and/or with a p53 overexpression plasmid. p53 transcriptional activity was assessed by ELISA and target reporter constructs. Results miR-34a, apoptosis and acetylated p53 increased with disease severity, while SIRT1 diminished in the NAFLD liver. UDCA inhibited the miR-34a/SIRT1/p53 pathway in the rat liver in vivo and in primary rat hepatocytes. miR-34a overexpression confirmed its targeting by UDCA, which prevented miR-34a-dependent repression of SIRT1, p53 acetylation, and apoptosis. Augmented apoptosis by FFAs in miR-34a overexpressing cells was also inhibited by UDCA. Finally, p53 overexpression activated miR-34a/SIRT1/p53, which in turn was inhibited by UDCA, via decreased p53 transcriptional activity. Conclusions Our results support a link between liver cell apoptosis and miR-34a/SIRT1/p53 signaling, specifically modulated by UDCA, and NAFLD severity. Potential endogenous modulators of NAFLD pathogenesis may ultimately provide new tools for therapeutic intervention.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The Three-Factor Eating Questionnaire (TFEQ) is one of the most widely used instruments to study different eating behaviors. It measures three types of eating behaviors namely: cognitive restraint, ...uncontrolled eating and emotional eating. The present study aims to evaluate the factor structure and reliability of the Portuguese version of the TFEQ-R21, using a confirmatory factor analysis (CFA). The sample includes 468 participants from the general population, with ages ranging from 18 to 60 years. Results from the CFA confirmed the TFEQ-R21 three-factor structure and the model revealed an acceptable fit to the data (
χ
2
(186) = 443.211,
p
< 0.001;
χ
2
/
df
= 2.329; CFI = 0.933; TLI = 0.925; RMSEA = 0.054; SMRS = 0.053). Multi-group analysis results support strong measurement invariance across genders. Furthermore, all three dimensions presented adequate psychometric properties. Overall, results support that the Portuguese version of the TFEQ-R21 is a useful, reliable and robust instrument to assess relevant eating behaviors.
Level of evidence
V, descriptive studies.
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FZAB, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Based on conventional S-20 processes, a new series of high quantum efficiency (QE) photocathodes has been developed that can be specifically tuned for use in the ultraviolet, blue or green regions of ...the spectrum. The QE values exceed 30% at maximum response, and the dark count rate is found to be as low as 30 Hz/cm super(2) at room temperature. This combination of properties along with a fast temporal response makes these photocathodes ideal for application in photon counting detectors, which is demonstrated with an MCP photomultiplier tube for single and multi-photoelectron detection.
Mark Weiser coined the term Ubiquitous Computing (UbiComp) describing a future in which everyday life-objects would have embedded computers providing services anytime and anywhere. This paradigm is ...theme recurrent in many graduate courses of Computer Science around the world. To better understand the challenge of teaching Ubiquitous Computing (UbiComp), we surveyed 15 professors and 60 graduate and undergraduate students from 16 universities. According to this survey, the two most challenging Ubicomp concepts to explain in a lecture are context-awareness and middleware platforms. Results also showed professors’ difficulty in finding tools to assist the practical teaching of UbiComp’s concepts. Current UbiComp tools require high programming skills or they are not designed for educational purposes. Therefore, this work presents the design, development, and evaluation of LUCy (Learning Ubiquitous Computing Easily), a Virtual Learning Environment which aids UbiComp practical classes. LUCy has two main elements: a Web tool and an Android mobile app. The former provides UbiComp theory materials, videos, practices, and simulations. The latter uses smartphones features and sensors to run simulations of UbiComp concepts. We evaluated LUCy during Context-Awareness classes in UbiComp courses, at the same university, along with three distinct semesters. In different three sessions, we gathered information about LUCy’s pedagogical and usability issues. Then, we performed a quasi-experiment using a pretest and posttest design methodology with twenty-seven students. Results showed LUCy practices significantly improves students reasoning about Context-Aware concepts.
A pepperpot emittance meter was used to measure the transverse emittance of multiply charged beams from REXEBIS, an Electron Beam Ion Source (EBIS) used for charge breeding of radioactive ion beams. ...The emittance meter is equipped with a Micro Channel Plate (MCP), a phosphor screen and a CCD camera for detection of the ion signal. The pulsed beam structure of low duty cycle imposes challenging constraints on the detector settings. In this article we give a careful analysis of the optimal operating parameters of the pepperpot emittance meter for ion beams of varying intensities. Emittance values for mass-separated and non-separated beams for different operating modes of the EBIS are presented. Furthermore we report on aberrations created in our injection∕extraction system.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
THGEM based photon detector for Cherenkov imaging applications Alexeev, M.; Birsa, R.; Bradamante, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Volume:
617, Issue:
1
Journal Article
Peer reviewed
We are developing a single photon detector for Cherenkov imaging counters. This detector is based on the use of THGEM electron multipliers in a multilayer design. The major goals of our project are ...ion feedback suppression down to a few per cent, large gain, fast response, insensitivity to magnetic fields, and a large detector size.
We report about the project status and perspectives. In particular, we present a systematic study of the THGEM response as a function of geometrical parameters, production techniques and the gas mixture composition. The first figures obtained from measuring the response of a CsI coated THGEM to single photons are presented.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
20.
Micropattern gaseous photon detectors for Cherenkov imaging counters Alexeev, M.; Birsa, R.; Bradamante, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Volume:
623, Issue:
1
Journal Article
Peer reviewed
We are developing a detector of single photons for application in Cherenkov imaging counters, based on the use of a multilayer architecture of THGEM electron multipliers coupled to a solid state CsI ...photocathode. The main goals of our project are ion feedback suppression down to a few per cent level, large gain, fast response, good time resolution, insensitivity to magnetic field and large detector size. We report about the project status and perspectives.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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