799 resultados para AIR ACTIVITY
Resumo:
The study of the electrodeposition of polycrystalline gold in aqueous solution is important from the viewpoint that in electrocatalysis applications ill-defined micro- and nanostructured surfaces are often employed. In this work, the morphology of gold was controlled by the electrodeposition potential and the introduction of Pb(CH3COO)2•3H2O into the plating solution to give either smooth or nanostructured gold crystallites or large dendritic structures which have been characterized by scanning electron microscopy (SEM). The latter structures were achieved through a novel in situ galvanic replacement of lead with AuCl4−(aq) during the course of gold electrodeposition. The electrochemical behavior of electrodeposited gold in the double layer region was studied in acidic and alkaline media and related to electrocatalytic performance for the oxidation of hydrogen peroxide and methanol. It was found that electrodeposited gold is a significantly better electrocatalyst than a polished gold electrode; however, performance is highly dependent on the chosen deposition parameters. The fabrication of a deposit with highly active surface states, comparable to those achieved at severely disrupted metal surfaces through thermal and electrochemical methods, does not result in the most effective electrocatalyst. This is due to significant premonolayer oxidation that occurs in the double layer region of the electrodeposited gold. In particular, in alkaline solution, where gold usually shows the most electrocatalytic activity, these active surface states may be overoxidized and inhibit the electrocatalytic reaction. However, the activity and morphology of an electrodeposited film can be tailored whereby electrodeposited gold that exhibits nanostructure within the crystallites on the surface demonstrated enhanced electrocatalytic activity compared to smaller smooth gold crystallites and larger dendritic structures in potential regions well within the double layer region.
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We demonstrate a simple electrochemical route to produce uniformly sized gold nanospikes without the need for a capping agent or prior modification of the electrode surface, which are predominantly oriented in the {111} crystal plane and exhibit promising electrocatalytic and SERS properties.
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This paper provides an outline of genre as we currently know it, and examines the changes occurring as games become more complex. Recent research we've undertaken suggests that our perception of which games fall into which genre category is subjective and that genre hybridization continues to blur our understanding of these categories. Consequently, it is becoming increasingly difficult to categorise game play experience based on traditional genre classifications. We examine the use of videogame activities as a useful mechanism for supplementing our understanding of videogame genre. Through considering activity as a means of classifying game experiences we may obtain a much more nuanced understanding of how players engage with games within a particular genre and across genres.
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Motor vehicles emit large quantities of ions in the form of both charged particles and molecular cluster ions. While, the health effects of inhalation of charged particles is largely unexplored, the concentrations near busy roads and the distance to which these particles and ions are carried have important implications for the exposure of the large percentage of the population that lives close to such roadways. We measured ion concentrations using a neutral cluster and air ion spectrometer (NAIS) near seven busy roads carrying on the average approximately 7000 vehicles hr-1 including about 15% heavy duty diesel vehicles. In this study, charged particle concentrations were measured as a function of downwind distance from the road for the first time. We show that, at a moderate wind speed of 2.0 m s-1, mean charged particle concentrations at the kerb were of the order of 2x104 cm-3 and, more importantly, decreased as d 0.6 where d is the distance from the road. While cluster ions were rapidly depleted by attachment to particles and were not carried to more than about 20 m from the road, elevated concentrations of charged particle were detected up to at least 400 m from the road. Most of the charge on the downwind side was carried on the larger particles, with no excess charge on particles smaller than about 10 nm. At 30 nm, particles carried more than double the charge they would normally carry in equilibrium. There are very few measurements of ions near road traffic and this is the first study of the spatial dispersion of charged particles from a road.
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The effects of suspension parameters and driving conditions on dynamic load-sharing of longitudinal-connected air suspensions of a tri-axle semi-trailer are investigated in this study. A novel nonlinear model of a multi-axle semi-trailer with longitudinal-connected air suspensions is formulated based on fluid mechanics and thermodynamics and validated through test results. The effects of road surface conditions, driving speeds, air line inside diameter and connector inside diameter on dynamic load-sharing capability of the semi-trailer were analyzed in terms of load-sharing criteria. Simulation results indicate that, when larger air lines and connectors are employed, the DLSC (Dynamic Load-Sharing Coefficient) optimization ratio reaches its peak value when the road roughness is medium. The optimization ratio fluctuates in a complex manner as driving speed increases. The results also indicate that if the air line inside diameter is always assumed to be larger than the connector inside diameter, the influence of air line inside diameter on load-sharing is more significant than that of the connector inside diameter. The proposed approach can be used for further study of the influence of additional factors (such as vehicle load, static absolute air pressure and static height of air spring) on load-sharing and the control methods for multi-axle air suspensions with longitudinal air line.
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Tumour angiogenesis has been recently recognised as one of the most important prognostic factors in lung cancer. Although a variety of angiogenic factors have been identified, the angiogenesis process remains poorly understood. Bcl-2, c-erbB-2 and p53 are well-known oncogenes involved in non- small-cell lung cancer pathogenesis. A direct correlation of thymidine phosphorylase (TP) and of vascular endothelial growth factor (VEGF) with intratumoural angiogenesis has been reported. In the present study we investigated the possible regulatory role if bcl-2, c-erB-2 proteins in angiogenesis and in VEGF and TP expression in non-small-cell lung cancer. Two hundred sixteen specimens from T1,2-NO, 1 staged patients treated with surgery alone were immunohistochemically examined. Bcl-2 and c-erbB-2 were significantly inversely related to each other (P = 0.04) and both were inversely associated with microvessel density (P < 0.02). High TP and VEGF reactivity was statistically related to loss of bcl-2 expression (P < 0.01). A significant co-expression of c-erbB-2 with TP was noted (P = 0.01). However, TP expression was related to high angiogenesis only in cases with absence of c-erB-2 expression (P < 0.0001). c-erbB-2 expression in poorly vascularised tumours was linked with poor outcome (P = 0.03). The present study provides strong evidence that the bcl-2 gene has a suppressive function over genes involved in both angiogenesis (VEGF and TP) and cell migration (c- erbB-2) in NSCLC. TP and c-erbB-2 proteins are significantly, and often simultaneously, expressed in bcl-2 negative cases. However, expression of the c-erbB-2 abolishes the TP-related angiogenic activity. Whether this is a result of a direct activity of the c-erbB-2 protein or a consequence of a c- erbB-2-related immune response remains to be further investigated.
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The aim of this study was to determine whether declines in knee flexor strength following overground repeat sprints were related to changes in hamstrings myoelectrical activity. Seventeen recreationally active males completed maximal isokinetic concentric and eccentric knee flexor strength assessments at 1800.s-1 before and after repeat sprint running. Myoelectrical activity of the biceps femoris (BF) and medial hamstrings (MH) was measured during all isokinetic contractions. Repeated measures mixed model (Fixed factors = time [pre- and post- repeat sprint] and leg [dominant and non-dominant], random factor = participants) design was fitted with the restricted maximal likelihood method. Repeat sprint running resulted in significant declines in eccentric, and concentric, knee flexor strength (eccentric = 25 ± 34 Nm, 15% p<0.001; concentric 11 Nm± 22 Nm, 10% p = 0.001). Eccentric BF myoelectrical activity was significantly reduced (10%; p= 0.033). Concentric BF and all MH myoelectrical activity were not altered. The declines in maximal eccentric torque were associated with the change in eccentric biceps femoris myoelectrical activity (p = 0.013). Following repeat sprint running there were preferential declines in the myoelectrical activity of the BF, which explained declines in eccentric knee flexor strength.
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Diesel particulate matter (DPM), in particular, has been likened in a somewhat inflammatory manner to be the ‘next asbestos’. From the business change perspective, there are three areas holding the industry back from fully engaging with the issue: 1. There is no real feedback loop in any operational sense to assess the impact of investment or application of controls to manage diesel emissions. 2. DPM are getting ever smaller and more numerous, but there is no practical way of measuring them to regulate them in the field. Mass, the current basis of regulation, is becoming less and less relevant. 3. Diesel emissions management is generally wholly viewed as a cost, yet there are significant areas of benefit available from good management. This paper discusses a feedback approach to address these three areas to move the industry forward. The six main areas of benefit from providing a feedback loop by continuously monitoring diesel emissions have been identified: 1. Condition-based maintenance. Emissions change instantaneously if engine condition changes. 2. Operator performance. An operator can use a lot more fuel for little incremental work output through poor technique or discipline. 3. Vehicle utilisation. Operating hours achieved and ratios of idling to under power affect the proportion of emissions produced with no economic value. 4. Fuel efficiency. This allows visibility into other contributing configuration and environmental factors for the vehicle. 5. Emission rates. This allows scope to directly address the required ratio of ventilation to diesel emissions. 6. Total carbon emissions - for NGER-type reporting requirements, calculating the emissions individually from each vehicle rather than just reporting on fuel delivered to a site.
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Using a sample of publicly listed firm in Korea from 2002 to 2006, this article examines the impact of board monitoring on firm value and productivity. We use outsider's attendance of board meetings as a proxy for board monitoring. Consistent with the commitment hypothesis, we find that outsider's attendance rate increases firm value, suggesting that attending board meeting itself is a strong signal that reflects outsider's intention to monitor insiders. While ownership of controlling shareholders negatively affects firm value, this relationship is not moderated by increased monitoring by outsiders. Our findings provide further evidence that the outside director system is less effective in chaebol-affiliated firms. Results also indicate that the effect of outsider's board monitoring activity on investor's valuation of the firm is greater than on productivity improvement of the firm. Our conclusions are robust for possible endogeneity in the relationship between firm value and board attendance by outside directors.
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Internet-connected tablets and smart phones are being used increasingly by young children. Little is known, however, about their social interactions with family members when engaged with these technologies. This article examines video-recorded interactions between a father and his two young children, one aged 18 months using an iPhone and one aged three years accessing an iPad. Drawing on Ethnomethodology and Conversation Analysis, analysis establishes ways the family members engage and disengage in talk so as to manage their individual activity with mobile devices and accomplish interaction with each other. Findings are relevant for understanding children’s everyday practices with mobile technologies.
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This paper provides details on comparative testing of axle-to-chassis forces of two heavy vehicles (HVs) based on an experimental programme carried out in 2007. Dynamic forces at the air springs were measured against speed and roughness values for the test roads used. One goal of that programme was to determine whether dynamic axle-to-chassis forces could be reduced by using larger-than-standard diameter longitudinal air lines. This paper presents a portion of the methodology, analysis and results from that programme. Two analytical techniques and their results are presented. The first uses correlation coefficients of the forces between air springs and the second is a student’s t-test. These were used to determine the causality surrounding improved dynamic load sharing between heavy vehicle air springs with larger air lines installed longitudinally compared with the standard sized air lines installed on the majority of air-sprung heavy vehicles.
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Purpose: Although oral fluoropyrimidine pro-drugs are increasingly being administered in preference to intravenous nucleoside analogues in cancer chemotherapy, their activation in malignant liver tissue may be insufficient. OGT 719 (1-galactopyranosyl-5-fluorouracil) is a novel nucleoside analogue, preferentially localized in hepatocytes and hepatoma cells via the asialoglycoprotein receptor. The aim of this study was to assess the systemic bioavailability of this rationally designed drug in 16 patients with advanced solid cancers. Method: Crossover pharmacokinetic study of oral (400 or 800 mg) and intravenous (250 mg/m 2) OGT 719. Results: Linear pharmacokinetics and oral bioavailability of approximately 25% were observed at the dose levels used in this study. Like other 5-FU prodrugs, considerable interpatient variability was observed in bioavailability following oral dosing. The mean half-life for oral doses was 4 h. OGT 719 was well tolerated. No objective tumour responses were demonstrated. Conclusion: The systemic bioavailability and half-life of oral OGT 719 are sufficient to merit dose escalation studies with frequent daily dosing. Subsequent efficacy studies should be performed in patients with primary and secondary liver malignancies.
Resumo:
Purpose: Although oral fluoropyrimidine pro-drugs are increasingly being administered in preference to intravenous nucleoside analogues in cancer chemotherapy, their activation in malignant liver tissue may be insufficient. OGT 719 (1-galactopyranosyl-5-fluorouracil) is a novel nucleoside analogue, preferentially localized in hepatocytes and hepatoma cells via the asialoglycoprotein receptor. The aim of this study was to assess the systemic bioavailability of this rationally designed drug in 16 patients with advanced solid cancers. Method: Crossover pharmacokinetic study of oral (400 or 800 mg) and intravenous (250 mg/m 2) OGT 719. Results: Linear pharmacokinetics and oral bioavailability of approximately 25% were observed at the dose levels used in this study. Like other 5-FU prodrugs, considerable interpatient variability was observed in bioavailability following oral dosing. The mean half-life for oral doses was 4 h. OGT 719 was well tolerated. No objective tumour responses were demonstrated. Conclusion: The systemic bioavailability and half-life of oral OGT 719 are sufficient to merit dose escalation studies with frequent daily dosing. Subsequent efficacy studies should be performed in patients with primary and secondary liver malignancies.
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Recent data from Australia, the United States and Europe show increased self-reported energy intake associated with obesity, in contrast to earlier suggestions that the obesity epidemic has occurred despite minimal or no increase in per capita energy intake from food. The effect of increased energy intake is compounded by sedentary lifestyles. Both physical activity and nutrition must be addressed to reduce the prevalence of obesity and improve the health of Australians.
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Purpose A phase II study was designed to assess the efficacy and safety of Caelyx (liposomal doxorubicin) in patients with advanced or metastatic gastric cancer. Methods A total of 25 patients with gastric adenocarcinoma were treated with Caelyx 45 mg/m2 every 28 days as first-line therapy for advanced disease. Patients were treated until tumour progression or unacceptable toxicity. Results One patient was withdrawn from the study after experiencing a severe infusion reaction. Of the 24 evaluable patients, 1 had a partial response, 7 had stable disease and the others progressed. Side effects, in particular palmar-plantar erythrodysaesthesia and haematological toxicity, were minor. Conclusions We conclude that while this dose and schedule of Caelyx in this patient group is acceptable, further studies with this regimen cannot be recommended due to the lack of antitumour activity seen.