2,889 research outputs found
Regional study of the Archean to Proterozoic crust at the Sudbury Neutrino Observatory (SNO+), Ontario: Predicting the geoneutrino flux
The SNO+ detector, a new kiloton scale liquid scintillator detector capable
of recording geoneutrino events, will define the strength of the Earth
radiogenic heat. A detailed 3-D model of the regional crust, centered at SNO+
and based on compiled geological, geophysical and geochemical information, was
used to characterize the physical and chemical attributes of crust and assign
uncertainties to its structure. Monte Carlo simulations were used to predict
the U and Th abundances and uncertainties in crustal lithologies and to model
the regional crustal geoneutrino signal originating from the at SNO+
Expected geoneutrino signal at JUNO
Constraints on the Earth's composition and on its radiogenic energy budget
come from the detection of geoneutrinos. The KamLAND and Borexino experiments
recently reported the geoneutrino flux, which reflects the amount and
distribution of U and Th inside the Earth. The KamLAND and Borexino experiments
recently reported the geoneutrino flux, which reflects the amount and
distribution of U and Th inside the Earth. The JUNO neutrino experiment,
designed as a 20 kton liquid scintillator detector, will be built in an
underground laboratory in South China about 53 km from the Yangjiang and
Taishan nuclear power plants. Given the large detector mass and the intense
reactor antineutrino flux, JUNO aims to collect high statistics antineutrino
signals from reactors but also to address the challenge of discriminating the
geoneutrino signal from the reactor background.The predicted geoneutrino signal
at JUNO is 39.7 TNU, based on the existing reference Earth
model, with the dominant source of uncertainty coming from the modeling of the
compositional variability in the local upper crust that surrounds (out to
500 km) the detector. A special focus is dedicated to the 6{\deg} x
4{\deg} Local Crust surrounding the detector which is estimated to contribute
for the 44% of the signal. On the base of a worldwide reference model for
reactor antineutrinos, the ratio between reactor antineutrino and geoneutrino
signals in the geoneutrino energy window is estimated to be 0.7 considering
reactors operating in year 2013 and reaches a value of 8.9 by adding the
contribution of the future nuclear power plants. In order to extract useful
information about the mantle's composition, a refinement of the abundance and
distribution of U and Th in the Local Crust is required, with particular
attention to the geochemical characterization of the accessible upper crust.Comment: Slight changes and improvements in the text,22 pages, 4 Figures, 3
Tables. Prog. in Earth and Planet. Sci. (2015
Perceiving the crust in 3D: a model integrating geological, geochemical, and geophysical data
Regional characterization of the continental crust has classically been
performed through either geologic mapping, geochemical sampling, or geophysical
surveys. Rarely are these techniques fully integrated, due to limits of data
coverage, quality, and/or incompatible datasets. We combine geologic
observations, geochemical sampling, and geophysical surveys to create a
coherent 3-D geologic model of a 50 x 50 km upper crustal region surrounding
the SNOLAB underground physics laboratory in Canada, which includes the
Southern Province, the Superior Province, the Sudbury Structure and the
Grenville Front Tectonic Zone. Nine representative aggregate units of exposed
lithologies are geologically characterized, geophysically constrained, and
probed with 109 rock samples supported by compiled geochemical databases. A
detailed study of the lognormal distributions of U and Th abundances and of
their correlation permits a bivariate analysis for a robust treatment of the
uncertainties. A downloadable 3D numerical model of U and Th distribution
defines an average heat production of 1.5W/m, and
predicts a contribution of 7.7TNU (a Terrestrial Neutrino Unit
is one geoneutrino event per 10 target protons per year) out of a
crustal geoneutrino signal of 31.1TNU. The relatively high
local crust geoneutrino signal together with its large variability strongly
restrict the SNO+ capability of experimentally discriminating among BSE
compositional models of the mantle. Future work to constrain the crustal heat
production and the geoneutrino signal at SNO+ will be inefficient without more
detailed geophysical characterization of the 3D structure of the heterogeneous
Huronian Supergroup, which contributes the largest uncertainty to the
calculation.Comment: 25 pages, 9 figures, 6 table
Prevalence of alcohol and drugs in urine of patients involved in road accidents
Objective. Road injuries are the leading injury-related cause of death among people aged 15-44. A clear dose-effect relationship has been demonstrated for drug and alcohol use and road traffic accidents. The objective of our study was to estimate the prevalence of drug and/or alcohol use in subjects admitted for road traffic accidents to an Emergency Department.
Methods. In this study, conducted between January and April
2006, 100 patients of both sexes (age 18-65) examined after
road traffic accidents were consecutively enrolled. A commercial
rapid urine test was used to detect drugs by the Emergency
Department staff. The alcohol concentration was determined
from a blood sample at the central laboratory.
Results. Most of the patients were drivers under 35 years of age.
67/100 road traffic accidents occurred at the weekend (Friday-
Sunday), nearly 60% between 24:00-09:00 hrs; on non-weekend
days about 80% of road traffic accidents were recorded between
14:00-24:00 hrs (p inf. 0.0001). With the alcoholemia test and
urine test for drugs detection 43/100 patients showed a single
or multiple positivity. Alcohol and drug presence is relevant
during the weekend (37/43 cases), in contrast with non weekend
(6/43 cases) [OR 3.04 (95% CI 1.43; 6.46)]. Alcohol was
the most frequently detected abuse substance (72%), followed
by benzodiazepines (42%), tetrahydrocannabinol (21%) and
cocaine (14%).
Discussion. 43% of patients examined were under the influence
of psychotropic substances (alcohol, drugs or both). The
greater part of road traffic accidents in positive test patients
occurred during the week-end, in particular during the late
night/early morning hours, probably after recreational time.
The high incidence of alcohol and/or drug abuse may have
caused physical and/or psychological problems, therefore the
high number of road traffic accidents, especially if taken in
combination.
Conclusion. The rapid urine test used cannot represent a diagnosis,
and requires a confirmation test. It can be used for medical
purposes as an easy and fast preliminary response which
enables a faster diagnostic and therapeutic guideline, but it
cannot be used for sanctions. Further studies are advisable with
an increase of number of patients, in a wider temporal range,
including control subjects, and using confirmation tests
nonalcoholic fatty liver disease is independently associated with an increased incidence of chronic kidney disease in patients with type 1 diabetes
OBJECTIVE There is no information about the role of nonalcoholic fatty liver disease (NAFLD) in predicting the development of chronic kidney disease (CKD) in type 1 diabetes. RESEARCH DESIGN AND METHODS We studied 261 type 1 diabetic adults with preserved kidney function and with no macroalbuminuria at baseline, who were followed for a mean period of 5.2 years for the occurrence of incident CKD (defined as estimated glomerular filtration rate [eGFR] 2 and/or macroalbuminuria). NAFLD was diagnosed by ultrasonography. RESULTS At baseline, patients had a mean eGFR of 92 ± 23 mL/min/1.73 m 2 ; 234 (89.7%) of them had normoalbuminuria and 27 (10.3%) microalbuminuria. NAFLD was present in 131 (50.2%) patients. During follow-up, 61 subjects developed incident CKD. NAFLD was associated with an increased risk of incident CKD (hazard ratio [HR] 2.85 [95% CI 1.59–5.10]; P P P P = 0.002). CONCLUSIONS This is the first study to demonstrate that NAFLD is strongly associated with an increased incidence of CKD. Measurement of NAFLD improves risk prediction for CKD, independently of traditional cardio-renal risk factors, in patients with type 1 diabetes
Synthesis of nucleoside-boronic esters hydrophobic pro-drugs: a possible route to improve hydrophilic nucleoside drug loading into polymer nanoparticles
Nucleoside analogues are active therapeutic agents for different types of diseases e.g. Cancer and virus infections. However, they are associated with several side effects due to off-target accumulation. Particulate delivery systems such as nanoparticles (NP) may be able to selectively target drug into affected organs and lower or omit off-target accumulation. Hydrophilic nucleoside analogues are poorly incorporated into NP. This work has used boronic compounds to synthesize more hydrophobic biodegradable pro-drugs of hydrophilic nucleosides to improve drug loading into NP. Ribavirin (RV) was used as a model hydrophilic nucleoside to test our hypothesis. RV is a broad antiviral agent, active against both RNA and DNA viruses. RV accumulates into Red Blood Cells (RBCs) causing haemolytic anaemia that restricts its therapeutic benefits. RBCs are reported to have no endocytic mechanisms. So, NP delivery should be advantageous. Two hydrophobic pro-drugs of RV were synthesized namely, ribavirin conjugated to phenylboronic acid and ribavirin conjugated to 4-butoxy-3, 5-dimethylphenylboronic acid and were encapsulated into polymer NP. It was shown that the pro-drugs were incorporated more effectively into polymer nanoparticles with a 1700 fold improved RV loading. Polymer NP had been prepared with biocompatible and biodegradable polymers, Poly(glycerol adipate) and its more hydrophobic derivatives
Geophysical and geochemical constraints on geoneutrino fluxes from Earth's mantle
Knowledge of the amount and distribution of radiogenic heating in the mantle
is crucial for understanding the dynamics of the Earth, including its thermal
evolution, the style and planform of mantle convection, and the energetics of
the core. Although the flux of heat from the surface of the planet is robustly
estimated, the contributions of radiogenic heating and secular cooling remain
poorly defined. Constraining the amount of heat-producing elements in the Earth
will provide clues to understanding nebula condensation and planetary formation
processes in early Solar System. Mantle radioactivity supplies power for mantle
convection and plate tectonics, but estimates of mantle radiogenic heat
production vary by a factor of more than 20. Recent experimental results
demonstrate the potential for direct assessment of mantle radioactivity through
observations of geoneutrinos, which are emitted by naturally occurring
radionuclides. Predictions of the geoneutrino signal from the mantle exist for
several established estimates of mantle composition. Here we present novel
analyses, illustrating surface variations of the mantle geoneutrino signal for
models of the deep mantle structure, including those based on seismic
tomography. These variations have measurable differences for some models,
allowing new and meaningful constraints on the dynamics of the planet. An ocean
based geoneutrino detector deployed at several strategic locations will be able
to discriminate between competing compositional models of the bulk silicate
Earth.Comment: 34 pages, 6 tables, 5 figures, 2 supplementary figures; revised
version submitted to Earth Planet. Sci. Let
Quercetin elevates p27Kip1 and arrests both primary and HPV16 E6/E7 transformed human keratinocytes in G1
Our previous work with primary bovine fibroblasts demonstrated that quercetin, a potent mutagen found in high levels in bracken fern (Pteridium aquilinum), arrested cells in G1 and G2/M, in correlation with p53 activation. The expression of bovine papillomavirus type 4 (BPV-4) E7 overcame this arrest and lead to the development of tumorigenic cells lines (Beniston et al., 2001). Given the possible link between papillomavirus infection, bracken fern in the diet and cancer of the upper gastrointestinal (GI) tract in humans, we investigated whether a similar situation would occur in human cells transformed by human papillomavirus type 16 (HPV-16) oncoproteins. Quercetin arrested primary human foreskin keratinocytes in G1. Arrest was linked to an elevation of the cyclin-dependent kinase inhibitor (cdki) p27Kip1. Expression of the HPV16 E6 and E7 oncoproteins in transformed cells failed to abrogate cell cycle arrest. G1 arrest in the transformed cells was also linked to an increase of p27Kip1 with a concomitant reduction of cyclin E-associated kinase activity. This elevation of p27Kip1 was due not only to increased protein half-life, but also to increased mRNA transcription
Extractants for evaluation of availability of heavy metals in soils fertilized with urban waste vermicompost
Os objetivos deste trabalho foram selecionar extratores químicos para avaliação da disponibilidade de metais pesados em solos tratados com vermicomposto de lixo urbano e calcário, e verificar os efeitos destes insumos nos teores disponíveis de metais pesados em solos. Foram realizados dois ensaios em casa de vegetação. Em um deles, foi usado um Latossolo Vermelho distroférrico e, no outro, um Argissolo Vermelho-Amarelo eutrófico, e, em ambos, a alface foi utilizada como planta-teste. O delineamento experimental de cada experimento foi em blocos ao acaso, em esquema fatorial 5x5, com quatro repetições, combinando-se doses de corretivos da acidez para elevar a saturação por bases a 40%, 50%, 60%, 70% e 80%, e o equivalente a 0, 25, 50, 75 e 100 t ha-1 de vermicomposto. Os extratores DTPA e Mehlich 3 detectam aumento nos teores de Ni, Pb, Cu e Zn em solos argiloso e arenoso adubados com vermicomposto de lixo urbano. O DTPA é mais eficiente que os extratores Mehlich 1 e Mehlich 3 na avaliação das alterações nos teores disponíveis dos metais pesados provocadas pelas mudanças no pH no solo argiloso. O Mn é o único elemento cuja disponibilidade é avaliada eficientemente tanto no solo argiloso como no arenoso, pelo DTPA.The objectives of this work were to select chemical extractants to evaluate the availability of heavy metals in soils treated with urban waste vermicompost and lime, and to verify the effects of these treatments in available contents of heavy metals in soils. Two experiments were carried out in greenhouse. An Oxissol was utilized in the first experiment and an Alfissol in the other. Lettuce was used as a testing plant in both experiments. The experiments followed a completely randomized design combining five liming levels, to elevate the base saturation to 40%, 50%, 60%, 70%, and 80%, with five vermicompost rates of 0, 25, 50, 75, and 100 tons ha-1, with four replicates. The DTPA and the Mehlich 3 detected increase in Ni, Pb, Cu and Zn contents in clay and sandy soils fertilized with urban waste vermicompost. The DTPA is more efficient than Mehlich 1 and Mehlich 3 to evaluate the changes in available contents of heavy metals caused by increase of pH in clay soil. The Mn is the only element which availability is efficiently evaluated in both soils, and the recomended extractant is the DTPA
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