4,815 research outputs found
Automated characterization of single-photon avalanche photodiode
We report an automated characterization of a single-photon detector based on
commercial silicon avalanche photodiode (PerkinElmer C30902SH). The photodiode
is characterized by I-V curves at different illumination levels (darkness, 10
pW and 10 uW), dark count rate and photon detection efficiency at different
bias voltages. The automated characterization routine is implemented in C++
running on a Linux computer.Comment: Have permission to post journal-formatted version on arXi
Measurement of stopping beam distributions in the PIBETA detector
Precise calculation of the geometrical acceptance of a large solid angle
detector with an integrated stopping target relies on precise knowledge of the
beam geometry. We describe four alternative methods that we used to measure the
beam stopping distributions in the PIBETA detector active target: (i) light
response of segmented target elements to incident beam particles, (ii)
back-tracking of charged particles from pi+ and mu+ decays using multi-wire
proportional chambers, (iii) volume distribution of the Dalitz decay
(pi0->gamma e+e-) event vertices, and (iv) the opening angle distribution of
two pi0 photons originating from the beta decay of pi+ at rest. We demonstrate
consistent results obtained by these four independent approaches and show how
particular beam stopping distributions affect the detector's geometrical
acceptance.Comment: 38 pages, 16 postscript figures, 2 tables, LaTeX, submitted to Nucl.
Instrum. Meth.
Benthic and Pelagic Pathways of Methylmercury Bioaccumulation in Estuarine Food Webs of the Northeast United States
Methylmercury (MeHg) is a contaminant of global concern that bioaccumulates and bioamagnifies in marine food webs. Lower trophic level fauna are important conduits of MeHg from sediment and water to estuarine and coastal fish harvested for human consumption. However, the sources and pathways of MeHg to these coastal fisheries are poorly known particularly the potential for transfer of MeHg from the sediment to biotic compartments. Across a broad gradient of human land impacts, we analyzed MeHg concentrations in food webs at ten estuarine sites in the Northeast US (from the Hackensack Meadowlands, NJ to the Gulf of Maine). MeHg concentrations in water column particulate material, but not in sediments, were predictive of MeHg concentrations in fish (killifish and Atlantic silversides). Moreover, MeHg concentrations were higher in pelagic fauna than in benthic-feeding fauna suggesting that MeHg delivery to the water column from methylation sites from within or outside of the estuary may be an important driver of MeHg bioaccumulation in estuarine pelagic food webs. In contrast, bulk sediment MeHg concentrations were only predictive of concentrations of MeHg in the infaunal worms. Our results across a broad gradient of sites demonstrate that the pathways of MeHg to lower trophic level estuarine organisms are distinctly different between benthic deposit feeders and forage fish. Thus, even in systems with contaminated sediments, transfer of MeHg into estuarine food webs maybe driven more by the efficiency of processes that determine MeHg input and bioavailability in the water column
Precision determination of band offsets in strained InGaAs/GaAs quantum wells by C-V-profiling and Schroedinger-Poisson self-consistent simulation
The results of measurements and numerical simulation of charge carrier
distribution and energy states in strained quantum wells In_xGa_{1-x}As/GaAs
(0.06 < x < 0.29) by C-V-profiling are presented. Precise values of conduction
band offsets for these pseudomorphic QWs have been obtained by means of
self-consistent solution of Schroedinger and Poisson equations and following
fitting to experimental data. For the conduction band offsets in strained
In_xGa_{1-x}As/GaAs - QWs the expression DE_C(x) = 0.814x - 0.21x^2 has been
obtained.Comment: 9 pages, 12 figures, RevTeX
Pericellular activation of hepatocyte growth factor by the transmembrane serine proteases matriptase and hepsin, but not by the membrane-associated protease uPA
HGF (hepatocyte growth factor) is a pleiotropic cytokine homologous to the serine protease zymogen plasminogen that requires canonical proteolytic cleavage to gain functional activity. The activating proteases are key components of its regulation, but controversy surrounds their identity. Using quantitative analysis we found no evidence for activation by uPA (urokinase plasminogen activator), despite reports that this is a principal activator of pro-HGF. This was unaffected by a wide range of experimental conditions, including the use of various molecular forms of both HGF and uPA, and the presence of uPAR (uPA receptor) or heparin. In contrast the catalytic domains of the TTSPs (type-II transmembrane serine proteases) matriptase and hepsin were highly efficient activators (50% activation at 0.1 and 3.4 nM respectively), at least four orders of magnitude more efficient than uPA. PS-SCL (positional-scanning synthetic combinatorial peptide libraries) were used to identify consensus sequences for the TTSPs, which in the case of hepsin corresponded to the pro-HGF activation sequence, demonstrating a high specificity for this reaction. Both TTSPs were also found to be efficient activators at the cell surface. Activation of pro-HGF by PC3 prostate carcinoma cells was abolished by both protease inhibition and matriptase-targeting siRNA (small interfering RNA), and scattering of MDCK (Madin–Darby canine kidney) cells in the presence of pro-HGF was abolished by inhibition of matriptase. Hepsin-transfected HEK (human embryonic kidney)-293 cells also activated pro-HGF. These observations demonstrate that, in contrast with the uPA/uPAR system, the TTSPs matriptase and hepsin are direct pericellular activators of pro-HGF, and that together these proteins may form a pathway contributing to their involvement in pathological situations, including cancer
Effectiveness and cost-effectiveness of biofeedback-assisted pelvic floor muscle training for female urinary incontinence: a multicentre randomised controlled trial
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordICS 2019: International Continence Society 49th Annual Meeting, 3-6 September 2019, Gothenburg, SwedenNational Institute for Health Research (NIHR
Intervention effects on dietary intake among children by maternal education level: results of the Copenhagen School Child Intervention Study (CoSCIS)
Dietary intake among Danish children, in general, does not comply with the official recommendations. The objectives of the present study were to evaluate the 3-year effect of a multi-component school-based intervention on nutrient intake in children, and to examine whether an intervention effect depended on maternal education level. A total of 307 children (intervention group: n 184; comparison group: n 123) were included in the present study. All had information on dietary intake pre- and post-intervention (mean age 6·8 and 9·5 years for intervention and comparison groups, respectively) assessed by a 7-d food record. Analyses were conducted based on the daily intake of macronutrients (energy percentage (E%)), fatty acids (E%), added sugar (E%) and dietary fibre (g/d and g/MJ). Analyses were stratified by maternal education level into three categories. Changes in nutrient intake were observed in the intervention group, mainly among children of mothers with a short education ( < 10 years). Here, intake of dietary fibre increased (β = 2·1 g/d, 95 % CI 0·5, 3·6, P= 0·01). Intake of protein tended to increase (β = 0·6 E%, 95 % CI − 0·01, 1·2, P= 0·05), while intake of fat (β = − 1·7 E%, 95 % CI − 3·8, 0·3, P= 0·09) and SFA (β = − 0·9, 95 % CI − 2·0, 0·2, P= 0·10) tended to decrease. Also, a significant intervention effect was observed on the intake of SFA among children of mothers with a long education (β = − 0·8, 95 % CI − 1·5, − 0·03, P= 0·04). This multi-component school-based intervention resulted in changes in the dietary intake, particularly among children of mothers with a short education. As the dietary intake of this subgroup generally differs most from the recommendations, the results of the present study are particularly encouraging
A nurse-led education and cognitive behaviour therapy-based intervention among adults with uncontrolled type 2 diabetes: A randomised controlled trial
Rationale, aims and objectives: Diabetes mellitus is associated with significant morbidity, mortality and escalating healthcare costs. Research has consistently demonstrated the importance of glycaemic control in delaying the onset, and decreasing the incidence, of both the short- and long-term complications of diabetes. Although glycaemic control is difficult to achieve and challenging to maintain, it is key to reducing negative disease outcomes. The aim of this study was to determine whether a nurse-led educational intervention alone or a nurse-led intervention using education and acceptance and commitment therapy (ACT) were effective in reducing HbA1c in people living with uncontrolled type 2 diabetes compared to usual care. Methods: Adults over the age of 18 years, with a confirmed diagnosis of type 2 diabetes and HbA1c outside of the recommended range (4-7%, 20-53 mmol/mol) for 12 months or more were eligible to participate. Participants were randomised to either a nurse-led education intervention, a nurse-led education plus ACT intervention or usual care. One hundred and eighteen participants completed baseline data collection (N=34 education group, N=39 education plus ACT, N=45 control group). An intention to treat analysis was employed. Results: A statistically significant reduction in HbA1c in the education intervention group was found (p=.011 [7.48, 8.14]). At 6 months, HbA1c was reduced in both intervention groups (Education group -0.21, education and ACT group -0.04) and increased in the control group (+0.32). A positive change in HbA1c (HbA1c reduced) was noted in 50 participants overall. Twice as many participants in the intervention groups demonstrated an improvement as compared to the control group (56% of the education group, 51% education plus ACT, and 24% control group. Conclusions: At 6 months post intervention, HbA1c was reduced in both intervention groups with a greater reduction noted in the nurse-led education intervention
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