2,089 research outputs found

    Physiological Responses to Prolonged Aquatic Hypoxia in the Queensland Lungfish Neoceratodus forsteri

    Get PDF
    The effects of moderate and severe hypoxia on air breathing frequency and respiratory properties of the blood of the Queensland (Australian) lungfish Neoceratodus forsteri were measured in fish exposed to these conditions for 14-22 days at 20 degrees C. Haemoglobin oxygen affinity increased after exposure to moderate hypoxia (PwO2 = 60 mmHg), but did not increase further after exposure to severe hypoxia (PwO2 =40 mmHg). The P50 of whole blood (20 degrees C, PCO2 =16.0 mmHg) fell from 22.0 +/- 1.5 mmHg in normoxic conditions to 19.0 +/- 1.0 mmHg in hypoxic conditions. Under both moderate and severe hypoxia, haematocrit, haemoglobin, blood lactate, and erythrocyte phosphate concentrations did not differ from normoxic values. The observed increase in haemoglobin oxygen affinity in response to aquatic hypoxia is typical of compensatory responses seen in obligate water breathers, but smaller. This suggests that the capacity of lungfish to respond to hypoxia by breathing air removes the necessity for further left-shifting of the oxygen equilibrium curve

    A 21-year record of vertically migrating subepilimnetic populations of Cryptomonas spp.

    Get PDF
    The vertical distribution and diel migration of Cryptomonas spp. were monitored continuously for 21 years in mesotrophic Cross Reservoir, northeast Kansas, USA. The movements of these motile algae were tracked on multiple dates during July–October of each year using in situ fluorometry and optical microscopy of Lugol’s iodine-preserved samples. Episodes of subepilimnetic diel vertical migration by Cryptomonas were detected and recorded on 221 different days between 1994 and 2014, with just 2 of these years (1998 and 2013) lacking any sampling events with deep peaks sufficiently large enough to track. Whenever a subepilimnetic layer of Cryptomonas was detectable, it was generally observed to ascend toward the bottom of the epilimnion beginning approximately at sunrise; to descend toward the lake bottom during the late afternoon and evening; and to remain as a deep-dwelling population until dawn of the following day. Moreover, there was high day-to-day consistency in the absolute water column depths at which the migrating algal cells would cease their ascending or descending movement. We believe this unique and remarkable dataset comprises the most detailed record of diel migratory behavior for any planktonic freshwater alga reported for a single freshwater lake

    The Advanced Data Acquisition Model (Adam): A Process Model for Digital Forensic Practice

    Get PDF
    As with other types of evidence, the courts make no presumption that digital evidence is reliable without some evidence of empirical testing in relation to the theories and techniques associated with its production. The issue of reliability means that courts pay close attention to the manner in which electronic evidence has been obtained and in particular the process in which the data is captured and stored. Previous process models have tended to focus on one particular area of digital forensic practice, such as law enforcement, and have not incorporated a formal description. We contend that this approach has prevented the establishment of generally-accepted standards and processes that are urgently needed in the domain of digital forensics. This paper presents a generic process model as a step towards developing such a generally-accepted standard for a fundamental digital forensic activity–the acquisition of digital evidence

    National trends and local delivery in old age mental health services: towards an evidence base: a mixed-methodology study of the balance of care approach, community mental health teams and specialist mental health outreach to care homes

    Get PDF
    Background The rising number of older people with mental health problems makes the effective use of mental health resources imperative. Little is known about the clinical effectiveness and/or cost-effectiveness of different service models. Aims The programme aimed to (1) refine and apply an existing planning tool [‘balance of care’ (BoC)] to this client group; (2) identify whether, how and at what cost the mix of institutional and community services could be improved; (3) enable decision-makers to apply the BoC framework independently; (4) identify variation in the structure, organisation and processes of community mental health teams for older people (CMHTsOP); (5) examine whether or not different community mental health teams (CMHTs) models are associated with different costs/outcomes; (6) identify variation in mental health outreach services for older care home residents; (7) scope the evidence on the association between different outreach models and resident outcomes; and (8) disseminate the research findings to multiple stakeholder groups. Methods The programme employed a mixed-methods approach including three systematic literature reviews; a BoC study, which used a systematic framework for choosing between alternative patterns of support by identifying people whose needs could be met in more than one setting and comparing their costs/outcomes; a national survey of CMHTs’ organisation, structure and processes; a multiple case study of CMHTs exhibiting different levels of integration encompassing staff interviews, an observational study of user outcomes and a staff survey; national surveys of CMHTs’ outreach activities and care homes. A planned randomised trial of depression management in care homes was removed at the review stage by the National Institute for Health Research (NIHR) prior to funding award. Results BoC: Past studies exhibited several methodological limitations, and just two related to older people with mental health problems. The current study suggested that if enhanced community services were available, a substantial proportion of care home and inpatient admissions could be diverted, although only the latter would release significant monies. CMHTsOP: 60% of teams were considered multidisciplinary. Most were colocated, had a single point of access (SPA) and standardised assessment documentation. Evidence of the impact of particular CMHT features was limited. Although staff spoke positively about integration, no evidence was found that more integrated teams produced better user outcomes. Working in high-integration teams was associated with poor job outcomes, but other factors negated the statistical significance of this. Care home outreach: Typical services in the literature undertook some combination of screening (less common), assessment, medication review, behaviour management and training, and evidence suggested intervention can benefit depressed residents. Care home staff were perceived to lack necessary skills, but relatively few CMHTs provided formal training. Limitations Limitations include a necessary reliance on observational rather than experimental methods, which were not feasible given the nature of the services explored. Conclusions BoC: Shifting care towards the community would require the growth of support services; clarification of extra care housing’s (ECH) role; timely responses to people at risk of psychiatric admission; and improved hospital discharge planning. However, the promotion of care at home will not necessarily reduce public expenditure. CMHTsOP: Although practitioners favoured integration, its goals need clarification. Occupational therapists (OTs) and social workers faced difficulties identifying optimal roles, and support workers’ career structures needed delineating. Care home outreach: Further CMHT input to build care home staff skills and screen for depression may be beneficial. Priority areas for further study include the costs and benefits for older people of age inclusive mental healt

    Investigation of Cellular Uptake Mechanism of Functionalised Gold Nanoparticles into Breast Cancer Using SERS

    Get PDF
    Gold nanoparticles (AuNPs) are widely used in various applications such as cancer imaging and drug delivery. The functionalisation of AuNPs has been shown to affect their cellular internalisation, accumulation and targeting efficiency. The mechanism of cellular uptake of functionalised AuNPs by different cancer cells is not well understood. Therefore, a detailed understanding of the molecular processes is necessary to improve AuNPs for their selective uptake and fate in specific cellular systems. This knowledge can greatly help in designing nanotags with higher cellular uptake for more selective and specific targeting capabilities with less off-target effects. Here, we demonstrate for the first time a straightforward and non-destructive 3D surface enhanced Raman spectroscopy (SERS) imaging approach to track the cellular uptake and localisation of AuNPs functionalised with an anti-ERα (estrogen receptor alpha) antibody in MCF-7 ERα-positive human breast cancer cells under different conditions including temperature and dynamin inhibition. 3D SERS enabled information rich monitoring of the intracellular internalisation of the SERS nanotags. It was found that ERα-AuNPs were internalised by MCF-7 cells in a temperature-dependent manner suggesting an active endocytosis-dependent mechanism. 3D SERS cell mapping also indicated that the nanotags entered MCF-7 cells using dynamin dependent endocytosis, since dynamin inhibition resulted in the SERS signal being obtained from, or close to, the cell surface rather than inside the cells. Finally, ERα-AuNPs were found to enter MCF-7 cells using an ERα receptor-mediated endocytosis process. This study addresses the role of functionalisation of SERS nanotags in biological environments and highlights the benefits of using 3D SERS for the investigation of cellular uptake processes

    Agronomic Management of Indigenous Mycorrhizas

    Get PDF
    Many of the advantages conferred to plants by arbuscular mycorrhiza (AM) are associated to the ability of AM plants to explore a greater volume of soil through the extraradical mycelium. Sieverding (1991) estimates that for each centimetre of colonized root there is an increase of 15 cm3 on the volume of soil explored, this value can increase to 200 cm3 depending on the circumstances. Due to the enhancement of the volume of soil explored and the ability of the extraradical mycelium to absorb and translocate nutrients to the plant, one of the most obvious and important advantages resulting from mycorrhization is the uptake of nutrients. Among of which the ones that have immobilized forms in soil, such as P, assume particular significance. Besides this, many other benefits are recognized for AM plants (Gupta et al, 2000): water stress alleviation (Augé, 2004; Cho et al, 2006), protection from root pathogens (Graham, 2001), tolerance to toxic heavy metals and phytoremediation (Audet and Charest, 2006; Göhre and Paszkowski, 2006), tolerance to adverse conditions such as very high or low temperature, high salinity (Sannazzaro et al, 2006), high or low pH (Yano and Takaki, 2005) or better performance during transplantation shock (Subhan et al, 1998). The extraradical hyphae also stabilize soil aggregates by both enmeshing soil particles (Miller e Jastrow, 1992) and producing a glycoprotein, golmalin, which may act as a glue-like substance to adhere soil particles together (Wright and Upadhyaya, 1998). Despite the ubiquous distribution of mycorrhizal fungi (Smith and Read, 2000) and only a relative specificity between host plants and fungal isolates (McGonigle and Fitter, 1990), the obligate nature of the symbiosis implies the establishment of a plant propagation system, either under greenhouse conditions or in vitro laboratory propagation. These techniques result in high inoculum production costs, which still remains a serious problem since they are not competitive with production costs of phosphorus fertilizer. Even if farmers understand the significance of sustainable agricultural systems, the reduction of phosphorus inputs by using AM fungal inocula alone cannot be justified except, perhaps, in the case of high value crops (Saioto and Marumoto, 2002). Nurseries, high income horticulture farmers and no-agricultural application such as rehabilitation of degraded or devegetated landscapes are examples of areas where the use of commercial inoculum is current. Another serious problem is quality of commercial available products concerning guarantee of phatogene free content, storage conditions, most effective application methods and what types to use. Besides the information provided by suppliers about its inoculum can be deceiving, as from the usually referred total counts, only a fraction may be effective for a particular plant or in specific soil conditions. Gianinazzi and Vosátka (2004) assume that progress should be made towards registration procedures that stimulate the development of the mycorrhizal industry. Some on-farm inoculum production and application methods have been studied, allowing farmers to produce locally adapted isolates and generate a taxonomically diverse inoculum (Mohandas et al, 2004; Douds et al, 2005). However the inocula produced this way are not readily processed for mechanical application to the fields, being an obstacle to the utilization in large scale agriculture, especially row crops, moreover it would represent an additional mechanical operation with the corresponding economic and soil compaction costs. It is well recognized that inoculation of AM fungi has a potential significance in not only sustainable crop production, but also environmental conservation. However, the status quo of inoculation is far from practical technology that can be widely used in the field. Together a further basic understanding of the biology and diversity of AM fungi is needed (Abbott at al, 1995; Saito and Marumoto, 2002). Advances in ecology during the past decade have led to a much more detailed understanding of the potential negative consequences of species introductions and the potential for negative ecological consequences of invasions by mycorrhizal fungi is poorly understood. Schwartz et al, (2006) recommend that a careful assessment documenting the need for inoculation, and the likelihood of success, should be conducted prior to inoculation because inoculations are not universally beneficial. Agricultural practices such as crop rotation, tillage, weed control and fertilizer apllication all produce changes in the chemical, physical and biological soil variables and affect the ecological niches available for occupancy by the soil biota, influencing in different ways the symbiosis performance and consequently the inoculum development, shaping changes and upset balance of native populations. The molecular biology tools developed in the latest years have been very important for our perception of these changes, ensuing awareness of management choice implications in AM development. In this context, for extensive farming systems and regarding environmental and economic costs, the identification of agronomic management practices that allow controlled manipulation of the fungal community and capitalization of AM mutualistic effect making use of local inoculum, seem to be a wise option for mycorrhiza promotion and development of sustainable crop production

    Longitudinal Evaluation of the Impact of Placement Development Teams on Student Support in Clinical Practice

    Get PDF
    AIMS: To investigate the impact of a new structure for supporting healthcare students and mentors in practice placements (Placement Development Teams). INTRODUCTION: The English Model National Partnership Agreement for healthcare education required Strategic Health Authorities, Higher Education Institutions and National Health Service Trusts to redesign strategies for student support. Placement Development Teams are one English University's response to this. MATERIALS AND METHODOLOGY: This study was phase 2 of a longitudinal qualitative evaluation of Placement Development Teams. Data were collected after establishment of Placement Development Teams, and compared and contrasted with those collected prior to their implementation. Telephone interviews were conducted with key educational stakeholders in Trusts and Strategic Health Authorities. Focus groups were conducted with third year non-medical healthcare students and first year paramedics working in 16 NHS Trusts in the south west peninsula of England. RESULTS: Pre-Placement Development Teams, themes from the students' data were: Supportive and unsupportive behaviour of staff; Mentor allocation; Placement allocation; Benefits of students to the placement area and Perceived control over the learning experience. Post-Placement Development Teams, the themes were Communication; Supportive and unsupportive behaviour of staff; The effect of peers on the placement experience; Knowledge and perceptions of the work of the PDTs. Form the staff data, pre-Placement Development Teams the themes were: Vision for improving student support. Post-Placement Development Teams themes from the staff data were how they provided a central point of contact for student and mentor support; and how they supported students and mentors. CONCLUSION: Support of students and mentors is particularly important following the introduction of The English Model National Partnership Agreement for healthcare education. Placement Development Teams can facilitate partnership working between higher education institutions and placement providers for student support

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

    Get PDF
    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
    corecore