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Zn plays an important role in maintaining the anti-oxidant status within the heart and helps to counter the acute redox stress that occurs during myocardial ischaemia and reperfusion. Individuals with low Zn levels are at greater risk of developing an acute myocardial infarction; however, the impact of this on the extent of myocardial injury is unknown. The present study aimed to compare the effects of dietary Zn depletion with in vitro removal of Zn (N,N,N′,N′-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN)) on the outcome of acute myocardial infarction and vascular function. Male Sprague–Dawley rats were fed either a Zn-adequate (35 mg Zn/kg diet) or Zn-deficient (<1 mg Zn/kg diet) diet for 2 weeks before heart isolation. Perfused hearts were subjected to a 30 min ischaemia/2 h reperfusion (I/R) protocol, during which time ventricular arrhythmias were recorded and after which infarct size was measured, along with markers of anti-oxidant status. In separate experiments, hearts were challenged with the Zn chelator TPEN (10 µm) before ischaemia onset. Both dietary and TPEN-induced Zn depletion significantly extended infarct size; dietary Zn depletion was associated with reduced total cardiac glutathione (GSH) levels, while TPEN decreased cardiac superoxide dismutase 1 levels. TPEN, but not dietary Zn depletion, also suppressed ventricular arrhythmias and depressed vascular responses to nitric oxide. These findings demonstrate that both modes of Zn depletion worsen the outcome from I/R but through different mechanisms. Dietary Zn deficiency, resulting in reduced cardiac GSH, is the most appropriate model for determining the role of endogenous Zn in I/R injury.
This research addresses dementia and driving cessation, a major life event for affected individuals, and an immense challenge in primary care. In Australia, as with many other countries, it is primarily general practitioners (GPs) who identify changes in cognitive functioning and monitor driving issues with their patients with dementia. Qualitative evidence from studies with family members and other health professionals shows it is a complicated area of practice. However we still know little from GPs about how they manage the challenges with their patients and the strategies that they use to facilitate driving cessation.
Data were collected through five focus groups with 29 GPs at their primary care practices in metropolitan and regional Queensland, Australia. A semi-structured topic guide was used to direct questions addressing decision factors and management strategies. Discussions were audio recorded, transcribed verbatim and thematically analyzed.
Regarding the challenges of raising driving cessation, four key themes emerged. These included: (i) Considering the individual; (ii) GP-patient relationships may hinder or help; (iii) Resources to support raising driver retirement; and (iv) Ethical dilemmas and ethical considerations. The impact of discussing driving cessation on GPs is discussed.
The findings of this study contribute to further understanding the experiences and needs of primary care physicians related to managing driving retirement with their patients with dementia. Results support a need for programs regarding identification and assessment of fitness to drive, to upskill health professionals and particularly GPs to manage the complex issues around dementia and driving cessation, and explore cost-effective and timely delivery of such support to patients.
The effectiveness of individually administered cognitive processing therapy (CPT) when compared with treatment as usual (TAU) in a community sexual assault centre was tested. Trauma survivors with acute stress disorder (ASD) following sexual assault were randomised to either CPT (n = 25) or TAU (n = 22), and assessed at pretreatment, posttreatment, and 3-, 6- and 12-month follow-up. Both groups demonstrated large reductions in PTSD and depression symptoms following treatment, and these gains were maintained over the course of follow-ups (Cohen's ds for PTSD symptom reductions ranging between 0.76 to 1.45). Although smaller and not always consistent, between-group effect sizes typically favoured CPT. Effect sizes (d) ranged between 0.13–0.50 for posttraumatic stress and 0.13–0.41 for depression over the course of follow-ups. Independent assessment of PTSD severity indicated more CPT participants reached good end-state functioning at 12-month follow-up (50%) than TAU (31%). Although both treatments were effective, there were some indications that CPT led to better outcomes relative to therapists delivering their usual therapy. The present study demonstrates that evidence-based, trauma-focused therapy such as CPT can be effective when delivered as an early intervention in a routine mental health setting.
The Implementing Geological Disposal of Radioactive Waste Technology Platform (IGD-TP) was launched in November 2009 to facilitate international cooperation in common areas of research, development and demonstration (RD&D) with a view to advancing the implementation of geological disposal facilities for spent fuel, high-level and other long-lived waste in Europe.
The IGD-TP's Vision is that “by 2025, the first geological disposal facilities for spent fuel, high-level waste and other long-lived radioactive waste will be operating safely in Europe”. Aside from most European waste management organisations, the IGD-TP currently has 124 members covering most of the RD&D actors in the field of implementing geological disposal of radioactive waste in Europe.
Five years after its inception, the IGD-TP has been shown to play a leading role in coordinating joint actions for RD&D in radioactive waste geological disposal programmes. The work of the platform takes into account differences between the timing and challenges for the respective waste management programmes. Following implementation of Posiva's geological disposal facility in Finland it is expected that within the next 5 years the construction of the Swedish and French geological disposal facilities will commence. Within IGD-TP, the SecIGD2 project whose remit is “Coordination and Support Action under the 7th Framework programme” aims at supporting, at the European level, the networking and structuring of RD&D programmes and competences in countries with less advanced geological disposal programmes, including those in the new European Union Member States. Furthermore, the SecIGD2 supports the development and coordination of the necessary competences to meet the Vision 2025 as a part of the platform's Competence Maintenance, Education and Training (CMET) working group.
Harvesting solar energy, is only one of the incentives of incorporating photosynthetic proteins in electrochemical devices. Understanding the interface of photosynthetic protein complexes and organic\inorganic underlying electrodes can give rise to development of new generation of nano-bioelectronics for other applications such as sensing, as well. Previous approaches in fabricating photosynthetic bio-hybrid electrochemical solar cells were mainly based on metallic electrodes with protein complexes attached, either directly or through linker molecules. Due to the energy band structure in semiconductors, they potentially can be useful for selective charge transfer in an electrochemical device. In the current study, a two terminal sealed bio-hybrid solar cell device was fabricated comprising of hydrothermally grown ZnO nanowires on fluorine doped tin oxide (FTO) glass working electrode, a Pt counter electrode, and methyl viologen (MV) as a single diffusible redox mediator. The ZnO working electrode was initially characterized using scanning electron microscopy (XRD) and X-ray diffraction (XRD). A solution of dimeric Rhodobacter sphaeroides – light harvesting 1 (RC-LH1) core complexes and redox electrolyte was injected into the cavity between working and counter electrodes. Such structure resulted in ∼0.64 µA.cm-2 photocurrent density and ∼0.24 V open circuit potential difference in the dark and under illumination. Additionally, the device stability tests demonstrated that the current response of such devices remained unchanged after 33 hours storage in the dark.
The device performance of GaAs p-i-n solar cells containing stacked layers of self-assembled InAs quantum dots is investigated. The solar cells demonstrate enhanced external quantum efficiency below the GaAs band gap relative to a control device without quantum dots. This is attributed to the capture of sub-band gap photons by the quantum dots. Analysis of the current density versus voltage characteristic for the quantum dot solar cell reveals a decrease in the series resistance as the device area is reduce from 0.16 cm2 to 0.01 cm2. This is effect is not observed in control devices and is quantum dot related. Furthermore, low temperature measurements of the open circuit voltage for both quantum dot and control devices provide experimental verification of the conditions required to realise an intermediate band gap solar cell.
Bacterial photosynthetic reaction centers (RCs) are promising materials for solar energy harvesting, due to their high internal quantum efficiency. However, applications of RCs in bio-photovoltaic devices so far show relatively low external power conversion efficiency, mainly due to low efficiency of the charge transfer to the electrode. Preferential orientation of RCs on an electrode’s surface can enhance the charge transfer rate to some extent. Yet, the results of direct coupling of RCs to an Au electrode, through cysteine residues from the H-subunit, revealed that direct electron transfer is not efficient. This work focuses on a different approach to achieve high charge transfer rate between an Au electrode and RC protein complexes by employing cytochrome c (Cyt c)\carboxylic acid-terminated linker molecules. This approach preferentially orients RCs with the primary donor site to the electrode. Furthermore, Cyt c can be considered as a conductive linker, while the charge transfer mechanism through carboxylic acid-terminated linker molecules is dominated by tunneling. The photochronoamperometric results for a two electrode cell setup indicated a 156 nA.cm-2 cathodic photocurrent density; the photocurrent was measured in an electrochemical cell with ubiquinone-10 (Q2) in the electrolyte. Negligible photocurrents were observed in the case of coupled RCs to the Au via cysteine residues on H-subunit, with only Cyt c in the electrolyte. These findings contribute to the design of highly efficient bio-photovoltaic devices.
The near field, together with the containment and isolation provided by the geosphere, contributes to the long-term safety provided by a geological disposal facility (GDF) after closure. The different engineered barriers can prevent or limit the release of radionuclides and their migration to the undisturbed host rock or geosphere and are expected to fulfil their post-closure safety functions for many thousands to hundreds of thousands of years. They will continue to contribute to containment after their eventual degradation when there would no longer be confidence that they would continue to fulfil all of their safety functions in their totality. By that time, significant radioactive decay will have occurred, substantially reducing the hazard associated with the wastes. Therefore, demonstration of long-term safety requires an understanding of the evolution of the engineered barriers and the consequences for the generic safety functions that the different barriers provide. This paper provides an overview of the research of the Nuclear Decommissioning Authority Radioactive Waste Management Directorate into the evolution of the near field of a GDF.
Reaction centers (RCs) from natural photosynthetic cells are photoactive proteins, which generate electron-hole pairs in presence of light. In a new approach presented in this work, a solution of suspended RCs with mediators has been applied as the electrolyte to build electrochemical based photovoltaic (PV) devices. In this approach, the mediators transfer charges from the RCs to the electrodes (indirect charge transfer). Various metallic and wide bandgap semiconducting materials, including Carbon, Au, Indium Tin Oxide (ITO), SnO2, WO3, have been tested as the electrodes. Among all WO3, which is a semiconductor, have shown the largest photocurrent density with an amount of ∼5.1 μA/cm2. The results show that the material of the electrode can affect the rates of the reactions in the cell. Choosing an appropriate material for the electrode, the charge transfer from the mediators to the electrode would be rectified to achieve a large photocurrent.
The high quantum efficiency (~100%) in the bacterial photosynthetic reaction center (RC) has inspired research on the application of RCs to build protein based solar cells. Conventionally, applying RCs as the photosensitive layer on the surface of a carbon electrode has shown poor photocurrents in the cells. The low photocurrent is partly due to the weak absorption of light in the monolayer of RCs. Also, an Atomic Force Microscopy image of the electrode shows lots of defects on the immobilized RCs at the electrode surface. In this work, we have built a bio-photoelectrochemical cell in which the RCs are floating in the electrolyte instead of being attached to the surface of an electrode. Despite the simple structure of the cell, the photocurrent is significantly higher in the new cell compared to when RCs are attached to an electrode. The amplitude of current reached to ~40 nA for free floating RCs, about five times larger than that in the cell with attached RCs. The aging effect was studied in both cells in a course of a week. The lifetime of attached RCs on electrode surface was slightly better than solubilized RCs in the electrolyte. Also, it is found that the mechanism which governs the charge transfer from RCs to the electrodes is the same in both bio-photoelectrochemical cells.
Red meat from grass-fed animals, compared with concentrate-fed animals, contains increased concentrations of long-chain (LC) n-3 PUFA. However, the effects of red meat consumption from grass-fed animals on consumer blood concentrations of LC n-3 PUFA are unknown. The aim of the present study was to compare the effects on plasma and platelet LC n-3 PUFA status of consuming red meat produced from either grass-fed animals or concentrate-fed animals. A randomised, double-blinded, dietary intervention study was carried out for 4 weeks on healthy subjects who replaced their habitual red meat intake with three portions per week of red meat (beef and lamb) from animals offered a finishing diet of either grass or concentrate (n 20 consumers). Plasma and platelet fatty acid composition, dietary intake, blood pressure, and serum lipids and lipoproteins were analysed at baseline and post-intervention. Dietary intakes of total n-3 PUFA, as well as plasma and platelet concentrations of LC n-3 PUFA, were significantly higher in those subjects who consumed red meat from grass-fed animals compared with those who consumed red meat from concentrate-fed animals (P < 0·05). No significant differences in concentrations of serum cholesterol, TAG or blood pressure were observed between groups. Consuming red meat from grass-fed animals compared with concentrate-fed animals as part of the habitual diet can significantly increase consumer plasma and platelet LC n-3 PUFA status. As a result, red meat from grass-fed animals may contribute to dietary intakes of LC n-3 PUFA in populations where red meat is habitually consumed.