1,338 research outputs found
Differentiation of adult-type Leydig cells occurs in gonadotrophin-deficient mice
During mammalian testis development distinct generations of fetal and adult Leydig cells arise. Luteinising hormone (LH) is required for normal adult Leydig cell function and for the establishment of normal adult Leydig cell number but its role in the process of adult Leydig cell differentiation has remained uncertain. In this study we have examined adult Leydig cell differentiation in gonadotrophin-releasing hormone (GnRH)-null mice which are deficient in circulating gonadotrophins. Adult Leydig cell differentiation was assessed by measuring expression of mRNA species encoding four specific markers of adult Leydig cell differentiation in the mouse. Each of these markers (3β-hydroxysteroid dehydrogenase type VI (3βHSD VI), 17β-hydroxysteroid dehydrogenase type III (17βHSD III), prostaglandin D (PGD)-synthetase and oestrogen sulphotransferase (EST)) is expressed only in the adult Leydig cell lineage in the normal adult animal. Real-time PCR studies showed that all four markers are expressed in adult GnRH-null mice. Localisation of 3βHSD VI and PGD-synthetase expression by in situ hybridisation confirmed that these genes are expressed in the interstitial tissue of the GnRH-null mouse. Treatment of animals with human chorionic gonadotrophin increased expression of 3βHSD VI and 17βHSD III within 12 hours further indicating that differentiated, but unstimulated cells already exist in the GnRH-null mouse. Thus, while previous studies have shown that LH is required for adult Leydig cell proliferation and activity, results from the present study show that adult Leydig cell differentiation will take place in animals deficient in LH
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Probabilistic design of optical transmission systems
Traditionally, optical fiber nonlinearity is considered a limiting factor for transmission systems. Nevertheless, from a system design perspective this nonlinearity can be exploited to minimize the impact of uncertainty on the system performance. A consequence of this is that it becomes beneficial to consider the uncertainty at the design stage, resulting in a probabilistic design, rather than conventional design approaches whereby uncertainty is added by way of system margins to a deterministic design. In this paper, we conduct extensive experimental measurements to quantify the impact of uncertainty for a multispan wavelength division multiplexed system transmitting 100 GbE or 200 GbE as dual polarization quadrature phase-shift keying (QPSK) or 16 quadrature amplitude modulation (16QAM), respectively. The impact of uncertainty in the power launched into a span is assessed for a 10 × 80 km link. For dual polarization (DP)-QPSK, the intralink power deviation with the probabilistic design with 100% reliability is ±1.3 dB falling to 99% reliability with ±1.6 dB. In contrast, for DP-16QAM maximum deviation for 100% reliability is ±0.5 dB falling to 99% for ±0.6 dB. Following this, we consider the interplay between polarization dependent loss (PDL) and fiber nonlinearity over an 8 × 80 km system again for both DP-QPSK and DP-16QAM. A system Q variation of less than 0.15 dB due to the interaction between PDL and fiber nonlinearity is observed for 99.9% of examined PDL values for DP-QPSK and DP-16QAM, thereby allowing the two effects to be considered separately.This research was supported by a Ciena University collaborative research grant. The work of H.-M. Chin was supported in part by a Ph.D. studentship from Ciena and in part by EU ICONE Project under Grant #608099. The work of S. J. Savory was supported by a Senior Research Fellowship from the RAEng/The Leverhulme Trust
Effect of atorvastatin on C-reactive protein and benefits for cardiovascular disease in patients with type 2 diabetes: analyses from the Collaborative Atorvastatin Diabetes Trial
CARDS was partially funded by Diabetes UK and the
National Health Service Research and Development Forum (England)
Comparison of the structure and activity of glycosylated and asglycosylated human carboxylesterase 1
Human Carboxylesterase 1 (hCES1) is the key liver microsomal enzyme responsible for detoxification and metabolism of a variety of clinical drugs. To analyse the role of the single N-linked glycan on the structure and activity of the enzyme, authentically glycosylated and aglycosylated hCES1, generated by mutating asparagine 79 to glutamine, were produced in human embryonic kidney cells. Purified enzymes were shown to be predominantly trimeric in solution by analytical ultracentrifugation. The purified aglycosylated enzyme was found to be more active than glycosylated hCES1 and analysis of enzyme kinetics revealed that both enzymes exhibit positive cooperativity. Crystal structures of hCES1 a catalytically inactive mutant (S221A) and the aglycosylated enzyme were determined in the absence of any ligand or substrate to high resolutions (1.86 Å, 1.48 Å and 2.01 Å, respectively). Superposition of all three structures showed only minor conformational differences with a root mean square deviations of around 0.5 Å over all Cα positions. Comparison of the active sites of these un-liganded enzymes with the structures of hCES1-ligand complexes showed that side-chains of the catalytic triad were pre-disposed for substrate binding. Overall the results indicate that preventing N-glycosylation of hCES1 does not significantly affect the structure or activity of the enzyme
Cross-cultural adaptation of the Internet Gaming Disorder Scale – Short Form (IGDS9-SF) to the Brazilian context
Introduction: The Internet Gaming Disorder Scale – Short Form (IGDS9-SF) assesses the severity, harmful effects and/or consequences of excessive online and offline gaming. Its conciseness and theoretical foundations on current diagnostic criteria of gaming disorders make it a useful resource for clinical and screening settings.
Objective: To describe the process of cross-cultural adaptation of the IGDS9-SF to the Brazilian context.
Methods: The cross-cultural adaptation involved the steps of independent translation of the instrument, synthesis version, back-translation, pre-test and elaboration of the final version. Content validity assessment was conducted by a multidisciplinary committee of experts and consisted of both a quantitative analysis (calculation of content validity coefficients – CVC) and a qualitative analysis (assessment of the experts’ comments and suggestions). The pre-test sample consisted of 30 gamers with variable sociodemographic characteristics.
Results: The cross-cultural adaptation of the scale followed the proposed protocol, and the CVC was satisfactory (≥ 0.83) for all the structures and equivalences assessed. Most of the suggestions made by the experts were accepted (mainly adjustments and language standardization). The gamers who participated in the pre-test judged the scale easy to understand and did not suggest changes.
Discussion: The Brazilian version of the IGDS9-SF showed adequate content validity and is available for researchers and clinicians, as well as for the investigation of additional psychometric characteristics
General beliefs about medicines among doctors and nurses in out-patient care: a cross-sectional study
Development and validation of Videogame Addiction Scale for Children (VASC)
The aim of the present study was to develop a valid and reliable Videogame Addiction Scale for Children (VASC). The data were derived from 780 children who completed the Videogame Addiction Scale (405 girls and 375 boys; 48.1% ranging in age from 9 to 12 years). The sample was randomly split into two different sub-samples (sample 1, n=400; sample 2, n= 380). Sample 1 was used to perform exploratory factor analysis (EFA) to define the factorial structure of VASC. As a result of EFA, a four-factor structure comprising 21 items was obtained and explained 55% of the total variance (the four factors being "self-control," "reward/reinforcement", "problems," and "involvement"). The internal consistency reliability of VASC has found 0.89. Confirmatory factor analysis (CFA) was performed to confirm the factorial structure obtained by EFA in the remaining half of sample (n= 390). The obtained fit indices from the CFA confirmed the structure of the EFA. The 21-item VASC has good psychometric properties that can be used among Turkish schoolchildren populations
Avoiding philosophy as a trump-card in sociological writing. A study from the discourse of evidence-based healthcare
In this article I explore a situation where health sociologists encounter pure-philosophical reasoning in the fabric of social life. Accounts of the relationship between philosophy and sociology tend to be framed in abstract theory, so there is a need for practical ways to anchor philosophical reasoning in sociological writing. I consider the use of philosophies as strategic tools for socially grounded understanding, rather than rhetorical trump-cards which bypass socio-political questions. I present my understanding in two stages: first, I discuss my example topic of Evidence-Based Healthcare (EBHC), reviewing some philosophical contributions by writers in that discourse. These niche-writings I contextualise briefly in relation to other academic meetings between philosophy and sociology. Second, I offer three philosophical perspectives on the topic of EBHC, and outline their significance for understanding it sociologically. I conclude that to navigate the difficult ground where philosophy and sociology meet, sociologists can entrain pure-philosophical argumentation to the purpose of critical, socially situated understandings.PostprintPeer reviewe
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV
The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration
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