353 research outputs found

    Impact of prior accumulated work and intensity on power output in elite/international level road cyclists—a pilot study

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    Background. This study aimed to investigate the impact of the intensity of prior accumulated work on the decline in power output in elite/international level road cyclists, comparing the effects of prior continuous moderate intensity versus intermittent high intensity cycling.Methods. Nine elite/international level road cyclists (age 26.2 +/- 4.0 years; body mass: 66.6 +/- 5.5 kg; height: 176 +/- 0.4 cm) conducted a 12-min field test (12 min(fresh)) during two consecutive training camps. Participants then performed both a 150-min moderate intensity continuous (MIC) work bout or a 150-min high intensity intermittent (HII) race simulation in randomized order, cross-over design. After each condition a 12-min field test (12 min(fatigue)) was completed.Results. Absolute and relative 12min(fresh) power output were not significantly different between training camps (p>0.05). The 12 min(fatigue) power after HII was significantly lower than 12min(fatigue) after MIC (Delta=14W; p=0.014). Participants recorded more percentage time (%Time) in heart rate (HR) zone 3 (Delta=9.2%; p=0.003) and power output band between 5.0-7.9W.kg(-1) (Delta=8.9%; p=0.002) as well as higher total work (Delta=237 kJ; p <= 0.001) during HII.Conclusion. These findings reveal that the decline in power output is higher after HII compared to MIC cycling work bouts. This suggests that the quantification of total work and intensity should be used in conjunction to predict a distinctive decline in power output. Future research is required to better understand the mechanisms of endurance "durability" in elite/international level road cyclists

    Exogenous pulmonary surfactant for the treatment of adult patients with acute respiratory distress syndrome: results of a meta-analysis

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    INTRODUCTION: The purpose of this study was to perform a systematic review and meta-analysis of exogenous surfactant administration to assess whether this therapy may be useful in adult patients with acute respiratory distress syndrome. METHODS: We performed a computerized literature search from 1966 to December 2005 to identify randomized clinical trials. The primary outcome measure was mortality 28–30 days after randomization. Secondary outcome measures included a change in oxygenation (PaO(2):FiO(2 )ratio), the number of ventilation-free days, and the mean duration of ventilation. Meta-analysis was performed using the inverse variance method. RESULTS: Two hundred and fifty-one articles were identified. Five studies met our inclusion criteria. Treatment with pulmonary surfactant was not associated with reduced mortality compared with the control group (odds ratio 0.97; 95% confidence interval (CI) 0.73, 1.30). Subgroup analysis revealed no difference between surfactant containing surface protein or not – the pooled odds ratio for mortality was 0.87 (95% CI 0.48, 1.58) for trials using surface protein and the odds ratio was 1.08 (95% CI 0.72, 1.64) for trials without surface protein. The mean difference in change in the PaO(2):FiO(2 )ratio was not significant (P = 0.11). There was a trend for improved oxygenation in the surfactant group (pooled mean change 13.18 mmHg, standard error 8.23 mmHg; 95% CI -2.95, 29.32). The number of ventilation-free days and the mean duration of ventilation could not undergo pooled analysis due to a lack of sufficient data. CONCLUSION: Exogenous surfactant may improve oxygenation but has not been shown to improve mortality. Currently, exogenous surfactant cannot be considered an effective adjunctive therapy in acute respiratory distress syndrome

    Hydrogen production from bio-oil: a thermodynamic analysis of sorption-enhanced chemical looping steam reforming

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    The steam reforming of pyrolysis bio-oil is one proposed route to low carbon hydrogen production, which may be enhanced by combination with advanced steam reforming techniques. The advanced reforming of bio-oil is investigated via a thermodynamic analysis based on the minimisation of Gibbs Energy. Conventional steam reforming (C-SR) is assessed alongside Sorption Enhanced Steam Reforming (SE-SR), Chemical Looping Steam Reforming (CLSR) and Sorption Enhanced Chemical Looping Steam Reforming (SE-CLSR). The selected CO2 sorbent is CaO(s) and oxygen transfer material (OTM) is Ni/NiO. PEFB bio-oil is modelled as a surrogate mixture and two common model compounds, acetic acid and furfural, are also considered. A process comparison highlights the advantages of sorption-enhancement and chemical looping, including improved purity and yield, and reductions in carbon deposition and process net energy balance. The operating regime of SE-CLSR is evaluated in order to assess the impact of S/C ratio, NiO/C ratio, CaO/C ratio and temperature. Autothermal operation can be achieved for S/C ratios between 1 and 3. In autothermal operation at 30 bar, S/C ratio of 2 gives a yield of 11.8wt%, and hydrogen purity of 96.9mol%. Alternatively, if autothermal operation is not a priority, the yield can be improved by reducing the quantity of OTM. The thermodynamic analysis highlights the role of advanced reforming techniques in enhancing the potential of bio-oil as a source of hydrogen

    A review of potential contaminants in Australian livestock feeds and proposed guidance levels for feed

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    Contaminants of man-made and natural origin need to be managed in livestock feeds to protect the health of livestock and that of human consumers of livestock products. This requires access to information on the transfer from feed to food to inform risk profiles and assessments, and to guide management interventions such as regulation or Hazard Analysis Critical Control Point approaches. This paper reviews contaminants of known and potential concern in the production of livestock feeds in Australia and compares existing but differing state and national regulatory standards with international standards. The contaminants considered include man-made organic chemical contaminants (e.g. legacy pesticides), elemental contaminants (e.g. arsenic, cadmium, lead), phytotoxins (e.g. gossypol) and mycotoxins (e.g. aflatoxins). Reference is made to scientific literature and evaluations by regulators to propose maximum levels that can be used for guidance by those involved in managing contamination incidents or developing feed safety programs. © 2013 CSIRO

    Phosphorylation and regulation of a G protein–coupled receptor by protein kinase CK2

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    We demonstrate a role for protein kinase casein kinase 2 (CK2) in the phosphorylation and regulation of the M3-muscarinic receptor in transfected cells and cerebellar granule neurons. On agonist occupation, specific subsets of receptor phosphoacceptor sites (which include the SASSDEED motif in the third intracellular loop) are phosphorylated by CK2. Receptor phosphorylation mediated by CK2 specifically regulates receptor coupling to the Jun-kinase pathway. Importantly, other phosphorylation-dependent receptor processes are regulated by kinases distinct from CK2. We conclude that G protein–coupled receptors (GPCRs) can be phosphorylated in an agonist-dependent fashion by protein kinases from a diverse range of kinase families, not just the GPCR kinases, and that receptor phosphorylation by a defined kinase determines a specific signalling outcome. Furthermore, we demonstrate that the M3-muscarinic receptor can be differentially phosphorylated in different cell types, indicating that phosphorylation is a flexible regulatory process where the sites that are phosphorylated, and hence the signalling outcome, are dependent on the cell type in which the receptor is expressed

    A design of experiments (DoE) approach to optimize cryogel manufacturing for tissue engineering applications

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    Marine origin polymers represent a sustainable and natural alternative to mammal counterparts regarding the biomedical application due to their similarities with proteins and polysaccharides present in extracellular matrix (ECM) in humans and can reduce the risks associated with zoonosis and overcoming social- and religious-related constraints. In particular, collagen-based biomaterials have been widely explored in tissue engineering scaffolding applications, where cryogels are of particular interest as low temperature avoids protein denaturation. However, little is known about the influence of the parameters regarding their behavior, i.e., how they can influence each other toward improving their physical and chemical properties. Factorial design of experiments (DoE) and response surface methodology (RSM) emerge as tools to overcome these difficulties, which are statistical tools to find the most influential parameter and optimize processes. In this work, we hypothesized that a design of experiments (DoE) model would be able to support the optimization of the collagen-chitosan-fucoidan cryogel manufacturing. Therefore, the parameters temperature (A), collagen concentration (B), and fucoidan concentration (C) were carefully considered to be applied to the Boxâ Behnken design (three factors and three levels). Data obtained on rheological oscillatory measurements, as well as on the evaluation of antioxidant concentration and adenosine triphosphate (ATP) concentration, showed that fucoidan concentration could significantly influence collagen-chitosan-fucoidan cryogel formation, creating a stable internal polymeric network promoted by ionic crosslinking bonds. Additionally, the effect of temperature significantly contributed to rheological oscillatory properties. Overall, the condition that allowed us to have better results, from an optimization point of view according to the DoE, were the gels produced at −80ºC and composed of 5% of collagen, 3% of chitosan, and 10% fucoidan. Therefore, the proposed DoE model was considered suitable for predicting the best parameter combinations needed to develop these cryogels.This research was funded by the Portuguese Foundation for Science and Technology (FCT) for Ph.D. fellowship (D.N.C.) under the scope of the doctoral program Tissue Engineering, Regenerative Medicine and Stem Cells, ref. PD/BD/143044/2018, for postdoctoral fellowship (C.G.), ref. SFRH/BPD/94277/2013. This work has been partially funded by ERDF under the scope of the Atlantic Area Program through project EAPA_151/2016 (BLUEHUMAN)

    A Mobile Concrete Laboratory to Support Quality Concrete, Technology Transfer, and Training

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    This report is a summary of work performed by the Mobile Infrastructure Materials Testing Laboratory (MIMTL) as a part of the Joint Transportation Research Program (JTRP) through SPR-3858. The development of the MIMTL began in February of 2014 and became fully operational by June of 2014. The MIMTL was deployed in the field for a total of 46 days. This report describes the activities of the MIMTL as of December 2015. The MIMTL was involved in the field testing of concrete bridges, concrete pavements, and asphalt pavements. This report describes the development of the mobile testing laboratory and provides some examples of how the MIMTL was used. The main highlights of the MIMTL’s implementation are as follows: The MIMTL’s high mobility and extensive inventory of research equipment allowed graduate students and researchers to conduct field studies on a wide range of infrastructure materials to accomplish the research objectives of their specific projects. More extensive details of the background, objectives, methods, findings, results and implementation from those projects can be found in the respective reports for those projects; The MIMTL supported a culture of safety that allowed students to work safely on jobsites in the State of Indiana ranging from roadside interstates, rural country roads, to ready-mix batching plants, often around heavy equipment, traffic, and in close quarters. During the operation of the MTIML described in this report, there were zero workplace accidents, and zero near misses reported; The MIMTL assisted in technology transfer between the infrastructure materials experts at Purdue University and contractors and suppliers in the State of Indiana. A wide range of new technologies evaluating infrastructure materials were utilized on a variety of projects. On each of these projects, MIMTL researchers educated industry personnel (contractors and suppliers), agency personnel (INDOT and local agencies), and consultants within the state. The MIMTL attended demonstrations with INDOT district and central office personnel to further highlight capabilities as well as the emerging technologies; The MIMTL was established a joint investment with partners in industry, local agencies, and INDOT. Operated by the Joint Transportation Research Program and the Local Technical Assistance Program as pay-per-use model, means this sustainable venture will offer services to researchers, industry, or agency entities that can cover the pay-per-use costs
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