754 research outputs found

    Aspects of the electrochemistry of the chemelec cell

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    The Chemelec Cell is an electrochemical reactor which achieves the recovery of metals from electroplating effluent by electrodeposition at concentrations too low to be considered for conventional electrolysis. The combination of a mesh-type configuration of electrodes together with the use of a non-conducting (inert) fluidised bed electrolyte engenders a sufficiently high rate of mass transport in the cell for efficient deposition to be carried out at metal ion concentrations below 1.0 gl-1. Two approaches have been made to the investigation of the system. First, experiments have been conducted using a laboratory scale Chemelec Cell in which the electrodeposition of nickel from Watts electrolytes has been carried out under a wide range of conditions of electrode potential, pH and metal ion concentration. Relatively long-term experiments have been attempted in which the cell is operated under conditions of constant electrode potential, temperature, pH and fluidisation and the fall of nickel ion concentration plotted as a function of time. Measurement of the charge passed (also as a function of time) has allowed access to the cathode current efficiency. Polarisation data, comprising two regions of electrode potential in which the current density varies semi-logarithmically with a large apparent Tafel slope (570 mV/dec.) separated by a region of some 300-500 mV in which the current density is almost independent of potential, have been obtained under these diffe rent conditions. An interpretation of these somewhat unusual characteristits has been sought. Secondly, more fundamental studies concerning the electrode kinetics of cadmium in various electrolytes have been carried out. The techniques of faradaic impedance, linear sweep voltammetry and the rotating disc have been applied and the results of these experiments interpreted. The presence of a hydroxide film on the electrode has been demonstrated and this obscures the true kinetics. Finally, the observed electrode kinetics and the experimental results obtained from the operation of the Chemelec Cell are compared and critically discussed

    New indium Lewis acids for catalysis

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    EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Athletes' experiences of social support during their transition out of elite sport: An interpretive phenomenological analysis

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    Objectives The sources and types of social support that athletes receive during the transition out of sport have been well documented. However, less is known about how athletes perceive, mobilise, and manage supportive relationships. This study aimed therefore to gain a more comprehensive insight into the ways that social support may influence how athletes adjust to life following retirement from elite sport. Design The study was designed according to the principles of Interpretative Phenomenological Analysis. Method Eight former British elite athletes (four male and four female) from eight different Olympic sports were recruited using criterion-based purposive sampling strategies. Data collected using semi-structured interviews were analysed to explore subjective experiences of social support during transition. Results Participants' perception of feeling cared for and understood enabled support to be effective. There were variations in participants' ability to seek out and ask for support and those who found this difficult also found transition a more distressing experience. As transitions progressed, the adjustment process was closely linked to the participant's evolving sense of self. New social relationships and social roles fostered a sense of feeling supported, as well as providing opportunities to support others (e.g., other retired athletes). Providing support helped the participants to experience a sense of growth that facilitated adjustment to life after sport. Conclusions The content of support was largely dependent on context; that is, perceptions of supporters were just as important, if not more so, than specific support exchanges. Stigma around asking for help was a barrier to support seeking

    Athletes’ retirement from elite sport: A qualitative study of parents and partners’ experiences

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    Objectives Athletes’ experiences of transition out of elite sport have been well documented. Less is known, however, about how the family members of athletes experience the process of transition. This study aimed to gain an in-depth understanding of parents and partners’ experiences and the way that they managed and interpreted their role in the process of transition. Method Individual semi-structured interviews were conducted with the parents and partners (two male and five female) of seven retired elite athletes from the UK. Data were analysed according to the principles of interpretative phenomenological analysis. Results Parents and partners experienced their own transition as they navigated uncertainty and upheaval in their own lives when the athletes retired. Parents and partners had to renegotiate their identity as they adjusted to changing roles and dynamics in their close relationships. Providing support to the former athletes was complicated by parents and partners’ own difficulties during transition and they often felt unsure about their role as a supporter. Parents and partners often experienced difficulties in their relationship with the athletes during their transition, but things improved as time went by. This was due to better communication and a willingness to share their feelings about their experiences. This helped parents and partners to gain a positive perspective on their transition and a sense that their relationship with the athletes had strengthened and grown. Conclusions Transition is often a shared experience and the findings of the present study underline the value of exploring transition at the level of the family or partnership as well as the individual

    APRIL: A double-blind, placebo-controlled, randomized, Phase Ib/IIa clinical study of ApTOLL for the treatment of acute ischemic stroke

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    Inflammation; Neuroprotection; StrokeInflamació; Neuroprotecció; IctusInflamación; Neuroprotección; IctusIn the reperfusion era, a new paradigm of treating patients with endovascular treatment (EVT) and neuroprotective drugs is emerging as a promising therapeutic option for patients with acute ischemic stroke (AIS). In this context, ApTOLL, a Toll-like receptor 4 (TLR4) antagonist with proven neuroprotective effect in preclinical models of stroke and a very good pharmacokinetic and safety profile in healthy volunteers, is a promising first-in-class aptamer with the potential to address this huge unmet need. This protocol establishes the clinical trial procedures to conduct a Phase Ib/IIa clinical study (APRIL) to assess ApTOLL tolerability, safety, pharmacokinetics, and biological effect in patients with AIS who are eligible for EVT. This will be a multicenter, double-blind, randomized, placebo-controlled, Phase Ib/IIa clinical study to evaluate the administration of ApTOLL together with EVT in patients with AIS. The study population will be composed of men and non-pregnant women with confirmed AIS with a <6h window from symptoms onset to ApTOLL/placebo administration. The trial is currently being conducted and is divided into two parts: Phase Ib and Phase IIa. In Phase Ib, 32 patients will be allocated to four dose ascending levels to select, based on safety criteria, the best two doses to be administered in the following Phase IIa in which 119 patients will be randomized to three arms of treatment (dose A, dose B, and placebo).The study is supported by grants from the Spanish Ministry of Science, Innovation and Universities (RTC-2017-6651-1 and RTC2019-006795-1). The funder was not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication

    Environmental toxicity, redox signaling and lung inflammation:the role of glutathione

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    Glutathione (γ-glutamyl-cysteinyl-glycine, GSH) is the most abundant intracellular antioxidant thiol and is central to redox defense during oxidative stress. GSH metabolism is tightly regulated and has been implicated in redox signaling and also in protection against environmental oxidant-mediated injury. Changes in the ratio of the reduced and disulfide form (GSH/GSSG) can affect signaling pathways that participate in a broad array of physiological responses from cell proliferation, autophagy and apoptosis to gene expression that involve H(2)O(2) as a second messenger. Oxidative stress due to oxidant/antioxidant imbalance and also due to environmental oxidants is an important component during inflammation and respiratory diseases such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, acute respiratory distress syndrome, and asthma. It is known to activate multiple stress kinase pathways and redox sensitive transcription factors such as Nrf2, NF-κB and AP-1, which differentially regulate the genes for pro-inflammatory cytokines as well as the protective antioxidant genes. Understanding the regulatory mechanisms for the induction of antioxidants, such as GSH, versus pro-inflammatory mediators at sites of oxidant-directed injuries may allow for the development of novel therapies which will allow pharmacological manipulation GSH synthesis during inflammation and oxidative injury. This article features the current knowledge about the role of GSH in redox signaling, GSH biosynthesis and particularly the regulation of transcription factor Nrf2 by GSH and downstream signaling during oxidative stress and inflammation in various pulmonary diseases. We also discussed the current therapeutic clinical trials using GSH and other thiol compounds, such as N-acetyl-L-cysteine, fudosteine, carbocysteine, erdosteine in environment-induced airways disease

    APRIL: a double-blind, placebo-controlled, randomized, Phase Ib/IIa clinical study of ApTOLL for the treatment of acute ischemic stroke

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    In the reperfusion era, a new paradigm of treating patients with endovascular treatment (EVT) and neuroprotective drugs is emerging as a promising therapeutic option for patients with acute ischemic stroke (AIS). In this context, ApTOLL, a Toll-like receptor 4 (TLR4) antagonist with proven neuroprotective effect in preclinical models of stroke and a very good pharmacokinetic and safety profile in healthy volunteers, is a promising first-in-class aptamer with the potential to address this huge unmet need. This protocol establishes the clinical trial procedures to conduct a Phase Ib/IIa clinical study (APRIL) to assess ApTOLL tolerability, safety, pharmacokinetics, and biological effect in patients with AIS who are eligible for EVT. This will be a multicenter, double-blind, randomized, placebo-controlled, Phase Ib/IIa clinical study to evaluate the administration of ApTOLL together with EVT in patients with AIS. The study population will be composed of men and non-pregnant women with confirmed AIS with a <6h window from symptoms onset to ApTOLL/placebo administration. The trial is currently being conducted and is divided into two parts: Phase Ib and Phase IIa. In Phase Ib, 32 patients will be allocated to four dose ascending levels to select, based on safety criteria, the best two doses to be administered in the following Phase IIa in which 119 patients will be randomized to three arms of treatment (dose A, dose B, and placebo).Peer ReviewedPostprint (published version

    The SEURAT-1 Approach towards Animal Free Human Safety Assessment

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    SEURAT-1 is a European public-private research consortium that is working towards animal-free testing of chemical compounds and the highest level of consumer protection. A research strategy was formulated based on the guiding principle to adopt a toxicological mode-of-action framework to describe how any substance may adversely affect human health. The proof of the initiative will be in demonstrating the applicability of the concepts on which SEURAT-1 is built on three levels: (i) Theoretical prototypes for adverse outcome pathways are formulated based on knowledge already available in the scientific literature on investigating the toxicological modes-of-action leading to adverse outcomes (addressing mainly liver toxicity); (ii) adverse outcome pathway descriptions are used as a guide for the formulation of case studies to further elucidate the theoretical model and to develop integrated testing strategies for the prediction of certain toxicological effects (i.e., those related to the adverse outcome pathway descriptions); (iii) further case studies target the application of knowledge gained within SEURAT-1 in the context of safety assessment. The ultimate goal would be to perform ab initio predictions based on a complete understanding of toxicological mechanisms. In the near-term, it is more realistic that data from innovative testing methods will support read-across arguments. Both scenarios are addressed with case studies for improved safety assessment. A conceptual framework for a rational integrated assessment strategy emerged from designing the case studies and is discussed in the context of international developments focusing on alternative approaches for evaluating chemicals using the new 21st century tools for toxicity testing

    ESAC Opinion on the Scientific Validity of the AR-CALUX Test Method

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    ESAC, the EURL ECVAM Scientific Advisory Committee, advises EURL ECVAM on scientific issues. Its main role is to conduct independent peer review of validation studies of alternative test methods and to assess their scientific validity for a given purpose. The committee reviews the appropriateness of study design and management, the quality of results obtained and the plausibility of the conclusions drawn. ESAC peer reviews are formally initiated with a EURL ECVAM Request for ESAC Advice, which provides the necessary background for the peer-review and establishes its objectives, timelines and the questions to be addressed. The peer review is normally prepared by specialised ESAC Working Groups. ESAC's advice to EURL ECVAM is formally provided as 'ESAC Opinions' and 'Working Group Reports' at the end of the peer review. ESAC may also issue Opinions on other scientific issues of relevance to the work and mission of EURL ECVAM but not directly related to a specific alternative test method. The ESAC Opinion expressed in this report relates to the peer-review of the AR-CALUX in vitro test method.JRC.F.3-Chemicals Safety and Alternative Method

    ESAC Opinion on the Scientific Validity of the Bioelution Test Method: ESAC Opinion No. 2019-03 of 2 December 2019

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    ESAC, the EURL ECVAM Scientific Advisory Committee, advises EURL ECVAM on scientific issues. Its main role is to conduct independent peer review of validation studies of alternative test methods and to assess their scientific validity for a given purpose. The committee reviews the appropriateness of study design and management, the quality of results obtained and the plausibility of the conclusions drawn. ESAC peer reviews are formally initiated with a EURL ECVAM Request for ESAC Advice, which provides the necessary background for the peer-review and establishes its objectives, timelines and the questions to be addressed. The peer review is normally prepared by specialised ESAC Working Groups. ESAC's advice to EURL ECVAM is formally provided as 'ESAC Opinions' and 'Working Group Reports' at the end of the peer review. ESAC may also issue Opinions on other scientific issues of relevance to the work and mission of EURL ECVAM but not directly related to a specific alternative test method. The ESAC Opinion expressed in this report relates to the peer-review of the Bioelution in vitro test method.JRC.F.3-Chemicals Safety and Alternative Method
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