536 research outputs found
Viral delivery of antioxidant genes as a therapeutic strategy in experimental models of amyotrophic lateral sclerosis.
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder with no effective treatment to date. Despite its multi-factorial aetiology, oxidative stress is hypothesized to be one of the key pathogenic mechanisms. It is thus proposed that manipulation of the expression of antioxidant genes that are downregulated in the presence of mutant SOD1 may serve as a therapeutic strategy for motor neuronal protection. Lentiviral vectors expressing either PRDX3 or NRF2 genes were tested in the motor neuronal-like NSC34 cell line, and in the ALS tissue culture model, NSC34 cells expressing the human SOD1(G93A) mutation. The NSC34 SOD1(G93A) cells overexpressing either PRDX3 or NRF2 showed a significant decrease in endogenous oxidation stress levels by 40 and 50% respectively compared with controls, whereas cell survival was increased by 30% in both cases. The neuroprotective potential of those two genes was further investigated in vivo in the SOD1(G93A) ALS mouse model, by administering intramuscular injections of adenoassociated virus serotype 6 (AAV6) expressing either of the target genes at a presymptomatic stage. Despite the absence of a significant effect in survival, disease onset or progression, which can be explained by the inefficient viral delivery, the promising in vitro data suggest that a more widespread CNS delivery is needed
Spatial mode storage in a gradient echo memory
Three-level atomic gradient echo memory (lambda-GEM) is a proposed candidate
for efficient quantum storage and for linear optical quantum computation with
time-bin multiplexing. In this paper we investigate the spatial multimode
properties of a lambda-GEM system. Using a high-speed triggered CCD, we
demonstrate the storage of complex spatial modes and images. We also present an
in-principle demonstration of spatial multiplexing by showing selective recall
of spatial elements of a stored spin wave. Using our measurements, we consider
the effect of diffusion within the atomic vapour and investigate its role in
spatial decoherence. Our measurements allow us to quantify the spatial
distortion due to both diffusion and inhomogeneous control field scattering and
compare these to theoretical models.Comment: 11 pages, 9 figure
An ethnographic investigation of maternity healthcare experience of immigrants in rural and urban Alberta, Canada
Background: Canada is among the top immigrant-receiving nations in the world. Immigrant populations may face structural and individual barriers in the access to and navigation of healthcare services in a new country. The aims of the study were to (1) generate new understanding of the processes that perpetuate immigrant disadvantages in maternity healthcare, and (2) devise potential interventions that might improve maternity experiences and outcomes for immigrant women in Canada.
Methods: The study utilized a qualitative research approach that focused on ethnographic research design and data analysis contextualized within theories of organizational behaviour and critical realism. Data were collected over 2.5 years using focus groups and in-depth semistructured interviews with immigrant women (n = 34), healthcare providers (n = 29), and social service providers (n = 23) in a Canadian province. Purposive samples of each subgroup were generated, and recruitment and data collection – including interpretation and verification of translations – were facilitated through the hiring of community researchers and collaborations with key informants.
Results: The findings indicate that (a) communication difficulties, (b) lack of information, (c) lack of social support (isolation), (d) cultural beliefs, e) inadequate healthcare services, and (f) cost of medicine/services represent potential barriers to the access to and navigation of maternity services by immigrant women in Canada. Having successfully accessed and navigated services, immigrant women often face additional challenges that influence their level of satisfaction and quality of care, such as lack of understanding of the informed consent process, lack of regard by professionals for confidential patient information, short consultation times, short hospital stays, perceived discrimination/stereotyping, and culture shock.
Conclusions: Although health service organizations and policies strive for universality and equality in service provision, personal and organizational barriers can limit care access, adequacy, and acceptability for immigrant women. A holistic healthcare approach must include health informational packages available in different languages/media. Health care professionals who care for diverse populations must be provided with training in cultural competence, and monitoring and evaluation programs to ameliorate personal and systemic discrimination
Electromagnetically induced transparency and four-wave mixing in a cold atomic ensemble with large optical depth
We report on the delay of optical pulses using electromagnetically induced
transparency in an ensemble of cold atoms with an optical depth exceeding 500.
To identify the regimes in which four-wave mixing impacts on EIT behaviour, we
conduct the experiment in both rubidium 85 and rubidium 87. Comparison with
theory shows excellent agreement in both isotopes. In rubidium 87, negligible
four-wave mixing was observed and we obtained one pulse-width of delay with 50%
efficiency. In rubidium 85, four-wave-mixing contributes to the output. In this
regime we achieve a delay-bandwidth product of 3.7 at 50% efficiency, allowing
temporally multimode delay, which we demonstrate by compressing two pulses into
the memory medium.Comment: 8 pages, 6 figure
Dual-rail optical gradient echo memory
We introduce a scheme for the parallel storage of frequency separated signals
in an optical memory and demonstrate that this dual-rail storage is a suitable
memory for high fidelity frequency qubits. The two signals are stored
simultaneously in the Zeeman-split Raman absorption lines of a cold atom
ensemble using gradient echo memory techniques. Analysis of the split-Zeeman
storage shows that the memory can be configured to preserve the relative
amplitude and phase of the frequency separated signals. In an experimental
demonstration dual-frequency pulses are recalled with 35% efficiency, 82%
interference fringe visibility, and 6 degrees phase stability. The fidelity of
the frequency-qubit memory is limited by frequency-dependent polarisation
rotation and ambient magnetic field fluctuations, our analysis describes how
these can be addressed in an alternative configuration.Comment: 8 pages, 4 figure
Can the quality of social research on ethnicity be improved through the introduction of guidance? Findings from a research commissioning pilot exercise
As the volume of UK social research addressing ethnicity grows, so too do concerns regarding the ethical and scientific rigour of this research domain and its potential to do more harm than good. The establishment of standards and principles and the introduction of guidance documents at critical points within the research cycle might be one way to enhance the quality of such research. This article reports the findings from the piloting of a guidance document within the research commissioning process of a major funder of UK social research. The guidance document was positively received by researchers, the majority of whom reported it to be comprehensible, relevant and potentially useful in improving the quality of research proposals. However, a review of the submitted proposals suggested the guidance had had little impact on practice. While guidance may have a role to play, it will need to be strongly promoted by commissioners and other gatekeepers. Findings also suggest the possibility that guidance may discourage some researchers from engaging with ethnicity if it raises problems without solutions; highlighting the need for complementary investments in research capacity development in this area
Gradient echo quantum memory in warm atomic vapor
Video Article - http://www.jove.com/video/50552Gradient echo memory (GEM) is a protocol for storing optical quantum states of light in atomic ensembles. The primary motivation for such a technology is that quantum key distribution (QKD), which uses Heisenberg uncertainty to guarantee security of cryptographic keys, is limited in transmission distance. The development of a quantum repeater is a possible path to extend QKD range, but a repeater will need a quantum memory. In our experiments we use a gas of rubidium 87 vapor that is contained in a warm gas cell. This makes the scheme particularly simple. It is also a highly versatile scheme that enables in-memory refinement of the stored state, such as frequency shifting and bandwidth manipulation. The basis of the GEM protocol is to absorb the light into an ensemble of atoms that has been prepared in a magnetic field gradient. The reversal of this gradient leads to rephasing of the atomic polarization and thus recall of the stored optical state. We will outline how we prepare the atoms and this gradient and also describe some of the pitfalls that need to be avoided, in particular four-wave mixing, which can give rise to optical gain.Olivier Pinel, Mahdi Hosseini, Ben M. Sparkes, Jesse L. Everett, Daniel Higginbottom, Geoff T. Campbell, Ping Koy Lam, Ben C. Buchle
Plugging a hole and lightening the burden: A process evaluation of a practice education team
Aim: To investigate the perceptions of clinical and senior managers about the role of Practice Educators employed in one acute hospital in the UK.
Background: Producing nurses who are fit for practice, purpose and academic award is a key issue for nurse education partnership providers in the UK. Various new models for practice learning support structures and new
roles within health care institutions have been established. To sustain funding and policy support for these models, there is a need for evaluation research.
Design: A process evaluation methodology was employed to determine the current value of a practice education team and to provide information to guide future direction.
Methods: Data were collected through semi-structured telephone interviews using a previously designed schedule. All senior nurse managers (N=5) and a purposive sample of clinical managers (n=13) who had personal experience of and perceptions about the role of practice educators provided the data. Interview notes were transcribed, coded and a thematic framework devised to present the results.
Results: A number of key themes emerged including: qualities needed for being a successful practice educator; visibility and presence of practice educators; providing a link with the university; ‘plugging a hole’ in supporting
learning needs; providing relief to practitioners in dealing with ‘the burden of students’; alleviating the ‘plight of students’; and effects on student attrition.
Conclusions: Findings provided evidence for the continued funding of the practice educator role with improvements to be made in dealing with stakeholder expectations and outcomes.
Relevance to clinical practice: In the UK, there still remain concerns about the fitness for practice of newly registered nurses, prompting a recent national consultation by the professional regulating body. Despite fiscal pressures, recommendations for further strengthening of all systems that will support the quality of practice learning may continue to sustain practice learning support roles
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