77 resultados para 13200-020
Resumo:
Toasting friends and family with realgar wines and painting children's foreheads and limbs with the leftover realgar/alcohol slurries is an important customary ritual during the Dragon Boat Festival (DBF); a Chinese national holiday and ancient feast day celebrated throughout Asia. Realgar is an arsenic sulfide mineral, and source of highly toxic inorganic arsenic. Despite the long history of realgar use during the DBF, associated risk to human health by arsenic ingestion or percutaneous adsorption is unknown. To address this urine samples were collected from a cohort of volunteers who were partaking in the DBF festivities. The total concentration of arsenic in the wine consumed was 70 mg L(-1) with all the arsenic found to be inorganic. Total arsenic concentrations in adult urine reached a maximum of ca. 550 mu g L(-1) (mean 220.2 mu g L(-1)) after 16 h post-ingestion of realgar wine, while face painting caused arsenic levels in children's urine to soar to 100 mu g L(-1) (mean 85.3 mu g L(-1)) 40 h after the initial paint application. The average concentration of inorganic arsenic in the urine of realgar wine drinkers on average doubled 16 h after drinking, although this was not permanent and levels subsided after 28 h. As would be expected in young children, the proportions of organic arsenic in the urine remained high throughout the 88-h monitoring period. However, even when arsenic concentrations in the urine peaked at 40 h after paint application, concentrations in the urine only declined slightly thereafter, suggesting pronounced longer term dermal accumulation and penetration of arsenic. Drinking wines blended with realgar or using realgar based paints on children does result in the significant absorption of arsenic and therefore presents a potentially serious and currently unquantified health risk. (C) 2011 Elsevier Ltd. All rights reserved.
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Post-weld heat-treatment (PWHT) was applied to NiTi weldments to improve the corrosion behaviour by modifying the microstructure and surface composition. The surface oxide film on the weldments is principally TiO2, together with some Ti, TiO, and Ti2O3. The surface Ti/Ni ratio of the weldments after PWHT is increased. The oxide film formed in Hanks’ solution is thicker on the weldments after PWHT. The pitting resistance of the weldments is increased by PWHT. The galvanic effect in the weldments is very small. The weldment with PWHT at 350 °C shows the best corrosion resistance among other heat-treated weldments in this study.
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Background: Studies investigating the association between glycated hemoglobin (HbA) level and mortality risk in diabetic patients receiving hemodialysis have shown conflicting results.
Study Design: We conducted a systematic review and meta-analysis using MEDLINE, EMBASE, Web of Science, and the Cochrane Library.
Setting & Population: Diabetic patients on maintenance hemodialysis therapy.
Selection Criteria for Studies: Observational studies or randomized controlled trials investigating the association between HbA values and mortality risk. Study authors were asked to provide anonymized individual patient data or reanalyze results according to a standard template.
Predictor: Single measurement or mean HbA values. Mean HbA values were calculated using all individual-patient HbA values during the follow-up period of contributing studies.
Outcome: HR for mortality risk.
Results: 10 studies (83,684 participants) were included: 9 observational studies and one secondary analysis of a randomized trial. After adjustment for confounders, patients with baseline HbA levels =8.5% (=69 mmol/mol) had increased mortality (7 studies; HR, 1.14; 95% CI, 1.09-1.19) compared with patients with HbA levels of 6.5%-7.4% (48-57 mmol/mol). Likewise, patients with a mean HbA value =8.5% also had a higher adjusted risk of mortality (6 studies; HR,1.29; 95% CI, 1.23-1.35). There was a small but nonsignificant increase in mortality associated with mean HbA levels =5.4% (=36 mmol/mol; 6 studies; HR, 1.09; 95% CI, 0.89-1.34). Sensitivity analyses in incident (=90 days of hemodialysis) and prevalent patients (>90 days of hemodialysis) showed a similar pattern. In incident patients, mean HbA levels =5.4% also were associated with increased mortality risk (4 studies; HR, 1.29; 95% CI, 1.23-1.35).
Limitations: Observational study data and inability to adjust for diabetes type in all studies.
Conclusions: Despite concerns about the utility of HbA measurement in hemodialysis patients, high levels (=8.5%) are associated with increased mortality risk. Very low HbA levels (=5.4%) also may be associated with increased mortality risk.
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Novel electrode structures for the direct methanol fuel cell (DMFC) based on Ti mesh are reported. A new anode with a hydrophilic structure prepared by coating Pt-Ru catalyst on Ti mesh using thermal decomposition showed a performance comparable to that of the conventional porous carbon-based structure one in DMFC, whilst a cathode with the same structure showed a poor performance. When a porous structure based on Ti mesh pre-coated with carbon was used as the cathode structure, the performance increased significantly to reach that of conventional carbon paper-based cathode. © 2005 Elsevier B.V. All rights reserved.
Resumo:
The mining/quarrying industry is a sector of industry where there are very few Life Cycle Assessment (LCA) tools, and where the role of LCA has been poorly investigated. A key issue is the integration of three inter-dependent life cycles: Project, Asset and Product. Given the unique features of mining LCAs, this Note from the Field presents a common methodology implemented within the Sustainable Aggregates Resource Management (SARMa) Project (www.sarmaproject.eu) in order to boost adoption of LCA in the aggregate industry in South Eastern Europe. The proposed methodology emphasises the importance of resource efficiency and recycling in the context of a Sustainable Supply Mix of aggregates for the construction industry. Through its adoption, aggregate producers, recyclers, and governmental planners would gain confidence with LCA tools and conduct consistent and meaningful life cycle analyses of natural and recycled aggregates. © 2011 Elsevier Ltd. All rights reserved.
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To determine whether internal limiting membrane (ILM) peeling improves anatomic and functional outcomes of full-thickness macular hole (FTMH) surgery when compared with the no-peeling technique.
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In situ forming (ISF) drug delivery implants have gained tremendous levels of interest over the last few decades. This is due to their wide range of biomedical applications such as in tissue engineering, cell encapsulation, microfluidics, bioengineering and drug delivery. Drug delivery implants forming upon injection has shown a range of advantages which include localized drug delivery, easy and less invasive application, sustained drug action, ability to tailor drug delivery, reduction in side effects associated with systemic delivery and also improved patient compliance and comfort. Different factors such as temperature, pH, ions, and exchange of solvents are involved in in situ implant formation. This review especially focuses on ISF implants that are formed through solvent induced phase inversion (SPI) technique. The article critically reviews and compares a wide range of polymers, solvents, and co-solvents that have been used in SPI implant preparation for control release of a range of drug molecules. Major drawback of SPI systems has been their high burst release. In this regard, the article exhaustively discusses factors that affect the burst release and different modification strategies that has been utilised to reduce the burst effect from these implants. Performance and controversial issues associated with the use of different biocompatible solvents in SPI systems is also discussed. Biodegradation, formulation stability, methods of characterisation and sterilisation techniques of SPI systems is comprehensively reviewed. Furthermore, the review also examines current SPI-based marketed products, their therapeutic application and associated clinical data. It also exemplifies the interest of multi-billion dollar pharma companies worldwide for further developments of SPI systems to a range of therapeutic applications. The authors believe that this will be the first review article that extensively investigate and discusses studies done to date on SPI systems. In so doing, this article will undoubtedly serve as an enlightening tool for the scientists working in the concerned area.
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Scour around bridge foundations is one of the leading causes of bridge failure. Up until recently, the monitoring of this phenomenon was primarily based around using underwater instrumentation to monitor the progression of scour holes as they develop around foundation systems. Vibration-based damage detection techniques have been used to detect damage in bridge beams. The application of these vibration based methods to the detection of scour has come to the fore in research in recent years. This paper examines the effect that scour has on the frequency response of a driven pile foundation system, similar to those used to support road and rail bridges. The effect of scour on the vibration characteristics of the pile is examined using laboratory and field testing. It is clear that there is a very clear reduction in the natural frequency of the pile as the severity of scour increases. It is shown that by combining state-of-the-art geotechnical techniques with relatively simple finite element modelling approaches, it is possible to accurately predict the natural frequency of the pile for a given scour depth. Therefore, the paper proposes a method that would allow the estimation of scour depth for a given observed pile frequency.
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The aqueous phase reforming (APR) of xylitol was studied in a continuous fixed bed reactor over three catalysts: Pt/Al2O3, Pt/TiO2 and Pt-Re/TiO2. The data obtained in the case of the monometallic Pt catalysts was compared to the bimetallic Pt-Re sample. The effect of Re addition on the catalyst stability, activity, product formation and selectivity toward hydrogen and alkanes was studied. The bimetallic catalyst demonstrated a higher selectivity to alkanes compared to the monometallic samples. The monometallic catalyst was more selective toward hydrogen formation. A plausible reaction scheme explaining differences in selectivity toward hydrogen and alkanes was proposed and discussed.
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Alcohol-induced liver injury is the most common liver disease in which fatty acid metabolism is altered. It is thought that altered NAD+/NADH redox potential by alcohol in the liver causes fatty liver by inhibiting fatty acid oxidation and the activity of tricarboxylic acid cycle reactions. β-Lapachone (βL), a naturally occurring quinone, has been shown to stimulate fatty acid oxidation in an obese mouse model by activating adenosine monophosphate-activated protein kinase (AMPK). In this report, we clearly show that βL reduced alcohol-induced hepatic steatosis and induced fatty acid oxidizing capacity in ethanol-fed rats. βL treatment markedly decreased hepatic lipids while serum levels of lipids and lipoproteins were increased in rats fed ethanol-containing liquid diets with βL administration. Furthermore, inhibition of lipolysis, enhancement of lipid mobilization to mitochondria and upregulation of mitochondrial β-oxidation activity in the soleus muscle were observed in ethanol/βL-treated animals compared to the ethanol-fed rats. In addition, the activity of alcohol dehydrogenase, but not aldehyde dehydrogenase, was significantly increased in rats fed βL diets. βL-mediated modulation of NAD+/NADH ratio led to the activation of AMPK signaling in these animals. Conclusion: Our results suggest that improvement of fatty liver by βL administration is mediated by the upregulation of apoB100 synthesis and lipid mobilization from the liver as well as the direct involvement of βL on NAD+/NADH ratio changes, resulting in the activation of AMPK signaling and PPARα-mediated β-oxidation. Therefore, βL-mediated alteration of NAD+/NADH redox potential may be of potential therapeutic benefit in the clinical setting.
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We present ultraviolet, optical, near-infrared photometry and spectroscopy of SN 2009N in NGC 4487. This object is a Type II-P supernova with spectra resembling those of subluminous II-P supernovae, while its bolometric luminosity is similar to that of the intermediate-luminosity SN 2008in. We created SYNOW models of the plateau phase spectra for line identification and to measure the expansion velocity. In the near-infrared spectra we find signs indicating possible weak interaction between the supernova ejecta and the pre-existing circumstellar material. These signs are also present in the previously unpublished near-infrared spectra of SN 2008in. The distance to SN 2009N is determined via the expanding photosphere method and the standard candle method as D = 21.6 ± 1.1 Mpc. The produced nickel-mass is estimated to be ∼0.020 ± 0.004 M⊙. We infer the physical properties of the progenitor at the explosion through hydrodynamical modelling of the observables. We find the values of the total energy as ∼0.48 × 1051 erg, the ejected mass as ∼11.5 M⊙, and the initial radius as ∼287 R⊙.
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Eye-tracking studies have shown how people with autism spend significantly less time looking at socially relevant information on-screen compared to those developing typically. This has been suggested to impact on the development of socio-cognitive skills in autism. We present novel evidence of how attention atypicalities in children with autism extend to real-life interaction, in comparison to typically developing (TD) children and children with specific language impairment (SLI). We explored the allocation of attention during social interaction with an interlocutor, and how aspects of attention (awareness checking) related to traditional measures of social cognition (false belief attribution). We found divergent attention allocation patterns across the groups in relation to social cognition ability. Even though children with autism and SLI performed similarly on the socio- cognitive tasks, there were syndrome-specific atypicalities of their attention patterns. Children with SLI were most similar to TD children in terms of prioritising attention to socially pertinent information (eyes, face, awareness checking). Children with autism showed reduced attention to the eyes and face, and slower awareness checking. This study provides unique and timely insight into real-world social gaze (a)typicality in autism, SLI and typical development, its relationship to socio-cognitive ability, and raises important issues for intervention.
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Objective: to explore maternal energy balance, incorporating free living physical activity and sedentary behaviour, in uncomplicated pregnancies at risk of macrosomia.
Methods: a parallel-group cross-sectional analysis was conducted in healthy pregnant women predicted to deliver infants weighing Z4000 g (study group) or o4000 g (control group). Women were recruited in a 1:1 ratio from antenatal clinics in Northern Ireland. Women wore a SenseWears Body Media Pro3 physical activity armband and completed a food diary for four consecutive days in the third trimester. Physical activity was measured in Metabolic Equivalent of Tasks (METs) where 1 MET¼1 kcal per kilogram of body weight per hour. Analysis of covariance (ANCOVA) was employed using the General Linear Model to adjust for potential confounders.
Findings: of the 112 women recruited, 100 complete datasets were available for analysis. There was no significant difference in energy balance between the two groups. Intensity of free living physical activity (average METs) of women predicted to deliver macrosomic infants (n¼50) was significantly lower than that of women in the control group (n¼50) (1.3 (0.2) METs (mean, standard deviation) versus 1.2 (0.2) METs; difference in means 0.1 METs (95% confidence interval: 0.19, 0.01); p¼0.021). Women predicted to deliver macrosomic infants also spent significantly more time in sedentary behaviour (r1 MET) than the control group (16.1 (2.8) hours versus 13.8 (4.3) hours; 2.0 hours (0.3, 3.7), p¼0.020).
Key conclusions and implications for practice: although there was no association between predicted fetal macrosomia and energy balance, those women predicted to deliver a macrosomic infant exhibited increased sedentary behaviour and reduced physical activity in the third trimester of pregnancy. Professionals caring for women during pregnancy have an important role in promoting and supporting more active lifestyles amongst women who are predicted to deliver a macrosomic infant given the known associated risks.
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Geomorphology plays a critical role in two areas of geoforensics: searching the land for surface or buried objects and sampling or imaging rural scenes of crime and control locations as evidence. Most of the associated geoscience disciplines have substantial bodies of work dedicated to their relevance in forensic investigations, yet geomorphology (specifically landforms, their mapping and evolution, soils and relationship to geology and biogeography) have had no such exposure. This is strange considering how fundamental to legal enquiries the location of a crime and its evolution are, as this article will demonstrate. This work aims to redress the balance by showing how geomorphology is featured in one of the earliest works on forensic science methods, and has continued to play a role in the sociology, archaeology, criminalistics and geoforensics of crime. The application geomorphology has in military/humanitarian geography and environmental/engineering forensics is briefly discussed as these are also regularly reviewed in courts of law
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This work presents the possibility of optimising 3D Organised Mesoporous Silica (OMS) coated with both iron and aluminium oxides for the optimal removal of As(III) and As(V) from synthetic contaminated water. The materials developed were fully characterised and were tested for removing arsenic in batch experiments. The effect of total Al to Fe oxides coating on the selective removal of As(III) and As(V) was studied. It was shown that 8% metal coating was the optimal configuration for the coated OMS materials in removing arsenic. The effect of arsenic initial concentration and pH, kinetics and diffusion mechanisms was studied, modelled and discussed. It was shown that the advantage of an organised material over an un-structured sorbent was very limited in terms of kinetic and diffusion under the experimental conditions. It was shown that physisorption was the main adsorption process involved in As removal by the coated OMS. Maximum adsorption capacity of 55 mg As(V).g-1 was noticed at pH 5 for material coated with 8% Al oxides while 35 mg As(V).g-1 was removed at pH 4 for equivalent material coated with Fe oxides.