231 research outputs found
Microbial Degradation of Gasoline in Soil: Effect of Season of Sampling
In cases where fire debris contains soil, microorganisms can rapidly and irreversibly alter the chemical composition of any ignitable liquid residue that may be present. In this study, differences in microbial degradation due to the season in which the sample is collected was examined. Soil samples were collected from the same site during Fall, Winter, Spring and Summer and the degradation of gasoline was monitored over 30 days. Predominant viable bacterial populations enumerated using real-time PCR and reverse transcriptase polymerase chain reaction (RT-PCR) enumeration revealed the predominant viable bacterial genera to be Alcaligenes, Bacillus, and Flavobacterium. Overall, the compounds most vulnerable to microbial degradation are the n-alkanes, followed by the mono-substituted alkylbenzenes (e.g., toluene, ethylbenzene, propylbenzene and isopropylbenzene). Benzaldehyde (a degradation product of toluene) was also identified as a marker for the extent of biodegradation. Ultimately, it was determined that soil collected during an unusually hot and dry summer exhibited the least degradation with little to no change in gasoline for up to 4 days, readily detectable n-alkanes for up to 7 days and relatively high levels of resilient compounds such as o-xylene, p-xylene and 1,3,5-trimethylbenzene. These results demonstrate, however, that prompt preservation and/or analysis of soil evidence is required in order to properly classify an ignitable liquid residue
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Monitoring on the performance of temporary props using wireless strain sensing
Although temporary props have been extensively used in underground support systems, their actual performance is poorly understood, resulting in potentially conservative and over-engineered design. This paper presents the performance monitoring of 4 temporary props in an urban construction site using a newly developed wireless strain sensor node featuring a 24-bit ADC. For each prop, 6 strain gauges and 3 temperature sensors were directly attached onto the prop surface using super glue, and then connected to a wireless strain sensor node mounted in the middle span. Each sensor node transmitted both monitoring data and network diagnostic messages in near-real-Time over an IPv6-based (6LoWPAN) wireless mesh sensor network. The data were also stored locally at each node on a micro SD card. Extensive testing and calibration was undertaken in the laboratory to ensure that the system functioned as expected. The prop loads are presented without correction for temperature effects and compared with the design loads. The monitoring data reveal the development of loads in temporary props during excavation, the formation of the basement and the extraction of the props. The network performance characteristics in terms of message reception ratio and network topology evolution are also highlighted and discussed
Prediction, prevention, and management of right ventricular failure after left ventricular assist device implantation: A comprehensive review
Left ventricular assist devices (LVADs) are increasingly common across the heart failure population. Right ventricular failure (RVF) is a feared complication that can occur in the early post-operative phase or during the outpatient follow-up. Multiple tools are available to the clinician to carefully estimate the individual risk of developing RVF after LVAD implantation. This review will provide a comprehensive overview of available tools for RVF prognostication, including patient-specific and right ventricle (RV)-specific echocardiographic and hemodynamic parameters, to provide guidance in patient selection during LVAD candidacy. We also offer a multidisciplinary approach to the management of early RVF, including indications and management of right ventricular assist devices in this setting to provide tools that help managing the failing RV
Deformed Minkowski spaces: clasification and properties
Using general but simple covariance arguments, we classify the `quantum'
Minkowski spaces for dimensionless deformation parameters. This requires a
previous analysis of the associated Lorentz groups, which reproduces a previous
classification by Woronowicz and Zakrzewski. As a consequence of the unified
analysis presented, we give the commutation properties, the deformed (and
central) length element and the metric tensor for the different spacetime
algebras.Comment: Some comments/misprints have been added/corrected, to appear in
Journal of Physics A (1996
Razvoj i validacija spektrofotometrijskih metoda za određivanje ceftazidima u farmaceutskim doziranim pripravcima
Two spectrophotometric methods for the determination of ceftazidime (CFZM) in either pure form or in its pharmaceutical formulations are described. The first method is based on the reaction of 3-methylbenzothiazolin-2-one hydrazone (MBTH) with ceftazidime in the presence of ferric chloride in acidic medium. The resulting blue complex absorbs at λmax 628 nm. The second method describes the reaction between the diazotized drug and N-(1-naphthyl)ethylenediamine dihydrochloride (NEDA) to yield a purple colored product with λmax at 567 nm. The reaction conditions were optimized to obtain maximum color intensity. The absorbance was found to increase linearly with increasing the concentration of CFZM; the systems obeyed the Beer’s law in the range 210 and 1050 µg mL1 for MBTH and NEDA methods, respectively. LOD, LOQ and correlation coefficient values were 0.15, 0.79 and 0.50, 2.61. No interference was observed from common excipients present in pharmaceutical formulations. The proposed methods are simple, sensitive, accurate and suitable for quality control applications.Razvijene su dvije spektrofotometrijske metode za određivanje ceftazidima (CFZM), čistog ili u farmaceutskim pripravcima. Prva metoda se temelji na reakciji 3-metilbenzotiazolin-2-on hidrazona (MBTH) sa ceftazidimom u prisutnosti željezovog(III) klorida u kiselom mediju. Nastaje plavi kompleks s maksimumom apsorpcije pri λmax 628 nm. Druga metoda se temelji na reakciji između diazotiranog lijeka i N-(1-naftil)etilendiamin dihidroklorida (NEDA), pri čemu nastaje ljubičasti produkt s λmax pri 567 nm. Reakcijski uvjeti su optimirani da se dobije maksimalni intenzitet boje. Apsorbancija raste linearno s porašću koncentracije CFZM; sustavi slijede Beerov zakon u koncentracijskom području 210 za MBTH metodu i 1050 µg mL1 za NEDA metodu. LOD i LOQ te vrijednosti korelacijskog koeficijenta su 0,15, 0,79 i 0,50, 2,61. Uobičajene pomoćne tvari ne smetaju određivanju ceftazidima. Predložene metode su jednostavne, osjetljive, točne i pogodne za primjenu u kontroli kvalitete
Muon-induced background in the EDELWEISS dark matter search
A dedicated analysis of the muon-induced background in the EDELWEISS dark
matter search has been performed on a data set acquired in 2009 and 2010. The
total muon flux underground in the Laboratoire Souterrain de Modane (LSM) was
measured to be \,muons/m/d. The
modular design of the muon-veto system allows the reconstruction of the muon
trajectory and hence the determination of the angular dependent muon flux in
LSM. The results are in good agreement with both MC simulations and earlier
measurements. Synchronization of the muon-veto system with the phonon and
ionization signals of the Ge detector array allowed identification of
muon-induced events. Rates for all muon-induced events and of WIMP-like events were extracted. After
vetoing, the remaining rate of accepted muon-induced neutrons in the
EDELWEISS-II dark matter search was determined to be at 90%\,C.L. Based on
these results, the muon-induced background expectation for an anticipated
exposure of 3000\,\kgd\ for EDELWEISS-3 is
events.Comment: 21 pages, 16 figures, Accepted for publication in Astropart. Phy
Situación nutricional de pacientes adultos que concurren a los centros de salud del Gran San Juan.
Se realizó un diagnóstico de la situación alimentario-nutricional de la población adulta que asiste a los 21 centros sanitarios pertenecientes al Gran San Juan, incluyéndose pacientes de 19 a 69 años de edad. El objetivo del trabajo ha sido valorar el estado nutricional de la población adulta, analizar los hábitos alimentarios, determinar la prevalencia de obesidad abdominal, identificar la frecuencia y tipo de actividad física, determinar el consumo de tabaco, formular una base de datos apropiada para articular entre Ministerios y otros sectores de la salud a fin de determinar estrategias de educación alimentario-nutricional que tiendan a disminuir el desarrollo de enfermedades asociadas a trastornos nutricionales, para mejorar la calidad de vida de la población
Longitudinal Changes of Mineral Concentrations in Preterm and Term Human Milk from Lactating Swiss Women.
<b></b> An adequate mineral supply to preterm infants is essential for normal growth and development. This study aimed to compare the mineral contents of human milk (HM) from healthy mothers of preterm (28-32 weeks) and full term (>37 weeks) infants. Samples were collected weekly for eight weeks for the term group (n = 34) and, biweekly up to 16 weeks for the preterm group (n = 27). Iron, zinc, selenium, copper, iodine, calcium, magnesium, phosphorus, potassium, and sodium were quantitatively analyzed by Inductively Coupled Plasma-Mass Spectrometry. The mineral contents of both HM showed parallel compositional changes over the period of lactation, with occasional significant differences when compared at the same postpartum age. However, when the comparisons were performed at an equivalent postmenstrual age, preterm HM contained less zinc and copper from week 39 to 48 (p < 0.002) and less selenium from week 39 to 44 (p < 0.002) than term HM. This translates into ranges of differences (min-max) of 53% to 78%, 30% to 72%, and 11% to 33% lower for zinc, copper, and selenium, respectively. These data provide comprehensive information on the temporal changes of ten minerals in preterm HM and may help to increase the accuracy of the mineral fortification of milk for preterm consumption
Recent insights on uncertainties present in integrated catchment water quality modelling
This paper aims to stimulate discussion based on the experiences derived from the QUICS project (Quantifying Uncertainty in Integrated Catchment Studies). First it briefly discusses the current state of knowledge on uncertainties in sub-models of integrated catchment models and the existing frameworks for analysing uncertainty. Furthermore, it compares the relative approaches of both building and calibrating fully integrated models or linking separate sub-models. It also discusses the implications of model linkage on overall uncertainty and how to define an acceptable level of model complexity. This discussion includes, whether we should shift our attention from uncertainties due to linkage, when using linked models, to uncertainties in model structure by necessary simplification or by using more parameters. This discussion attempts to address the question as to whether there is an increase in uncertainty by linking these models or if a compensation effect could take place and that overall uncertainty in key water quality parameters actually decreases. Finally, challenges in the application of uncertainty analysis in integrated catchment water quality modelling, as encountered in this project, are discussed and recommendations for future research areas are highlighted
Harnessing Infrared Photons for Photoelectrochemical Hydrogen Generation. A PbS Quantum Dot Based "Quasi-Artificial Leaf"
[EN] Hydrogen generation by using quantum dot (QD) based heterostructures has emerged as a promising strategy to develop artificial photosynthesis devices. In the present study, we sensitize mesoporous TiO2 electrodes with in-situ-deposited PbS/CdS QDs, aiming at harvesting light in both the visible and the near-infrared for hydrogen generation. This heterostructure exhibits a remarkable photocurrent of 6 mA.cm(-2), leading to 60 mL.cm(-2).day(-1) hydrogen generation. Most importantly, confirmation of the contribution of infrared photons to H-2 generation was provided by the incident-photon-to-current-efficiency (IPCE), and the integrated current was in excellent agreement with that obtained through cyclic voltammetry. The main electronic processes (accumulation, transport, and recombination) were identified by impedance spectroscopy, which appears as a simple and reliable methodology to evaluate the limiting factors of these photoelectrodes. On the basis of this TiO2/PbS/CdS heterostructrure, a "quasi-artificial leaf' has been developed, which has proven to produce hydrogen under simulated solar illumination at (4.30 +/- 0.25) mL.cm(-2).day(-1).We acknowledge support by projects from Ministerio de Economia y Competitividad (MINECO) of Spain (Consolider HOPE CSD2007-00007, MAT2010-19827), Generalitat Valenciana (PROMETEO/2009/058 and Project ISIC/2012/008 "Institute of Nanotechnologies for Clean Energies"), and Fundacio Bancaixa (P1.1B2011-50). S.G. acknowledges support by MINECO of Spain under the Ramon y Cajal programme. The SCIC of the University Jaume I de Castello is also acknowledged for the gas analysis measurements. C.S. acknowledges the POSDRU/89/1.5/S/58852 Project "Postdoctoral programme for training scientific researchers", co-financed by the European Social Fund within the Sectorial Operational Program Human Resources Development 2007-2013. We want to acknowledge Prof. J. Bisquert for the fruitful discussions related to this manuscript.Trevisan, R.; Rodenas, P.; González-Pedro, V.; Sima, C.; Sánchez, RS.; Barea, EM.; Mora-Sero, I.... (2013). Harnessing Infrared Photons for Photoelectrochemical Hydrogen Generation. A PbS Quantum Dot Based "Quasi-Artificial Leaf". Journal of Physical Chemistry Letters. 4(1):141-146. https://doi.org/10.1021/jz301890mS1411464
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