3,210 research outputs found
Studies on the Isolation of Messenger RNA
The rapidly-labeled RNA fraction of E. coli has been
purified approximately 15-fold on benzoylated DEAE cellulose
columns (BC). It is metabolically unstable (as shown
by a pulse/chase experiment) and is considered to represent
mRNA. The yield of pulse-labeled RNA is about 70% and
comprises 4-5% of the RNA of the cell.
The true size distribution of this RNA, determined by
sedimentation in a denaturing solvent (99% DMSO), does not
change during purification. This result indicates that
neither degradation nor selection for molecules of a particular
size has occurred. Upon sedimentation of the final
preparation in DMSO, the distribution of pulse label is
the same as that of RNA mass, indicating nearly complete
separation from longer-lived RNA components.
The isolation of globin-specific mRNA from rabbit
reticulocytes has been attempted, both by a modification
of BC chromatography and by the previously published
sucrose gradient method of Marbaix, Burny, and Chantrenne,
but the results (in both cases) were inconclusive. The
final preparation sedimented heterogeneously, with an
estimated mean sedimentation coefficient (s20,w) of 8.4 S.
Tests of the possible identity of this material as mRNA by
biological assay in a cell-free protein synthesizing
system have not been attempted.</p
Proposed guidelines and criteria for describing samples of persons with learning disabilities
The role of fitness professionals in performing contemporary health agendas: a critical analysis of 'effective' training, development and practice
Advanced capitalist societies are currently experiencing a series of widespread global public health challenges. The purpose of this research has been to explore the role of âfitness professionalsâ in this landscape and to understand whether and how they are able to make the contribution to public health that is claimed. The research was conducted over three iterative phases of research: (1) a comprehensive literature review; (2) five complex case studies of fitness professionals in practice; and (3) interviews with twenty key stakeholders/policymakers in the health, fitness and leisure sectors. The findings show that fitness professionals are an important, complex, undervalued and precarious health-related occupational group. Based on the research evidence, it is clear that there is a gap between the health- and fitness-related needs of society and the capacity of the health, fitness and leisure sectors to serve those needs effectively. Using âneoliberalismâ as a framework, it is argued that the occupational group of fitness professionals appears to highlight critical gaps in the neoliberal ideology concerning whether, how and under what circumstances the state should intervene in a health-related market. Recommendations are made for improving the practice and/or the development of practice for fitness professionals in the future
Evaluating the performance of the Motley Foolâs Stock Advisorâą
Since March 2002, The Motley Foolâs founders, David Gardner and Tom Gardner, have published monthly stock recommendations under Motley Foolâs premium Stock Advisor service. In this paper, the authors investigate whether analystsâ recommendations can add value for investors by examining the performance of portfolios constructed based on Motley Foolâs recommendations. They evaluate the announcement effect on share price corresponding to the publication of stock recommendations. Additionally, the researchers examine holding period returns for a portfolio imitating the actions of Stock Advisor. They find portfolios composed of recommendations through Stock Advisor added value initially upon recommendation and across extended holding periods. Additionally, the authors find that the Stock Advisor sample outperforms other sample portfolios on a risk-adjusted basis and over several subperiods. The findings contribute to the literature on the usefulness of analystsâ recommendations in adding value to investorsâ portfolios
Statin use in cancer survivors versus the general population: cohort study using primary care data from the UK clinical practice research datalink.
BACKGROUND: Cancer survivors may be at increased risk of cardiovascular diseases, but little is known about whether prescribing guidelines for the primary prevention of cardiovascular disease are adequately implemented in these patients. We compared levels of statin initiation and cessation among cancer survivors compared to the general population to determine differences in uptake of pharmaceutical cardiovascular risk prevention measures in these groups. METHODS: The study population included individuals aged â„40 during 2005-13 within the UK Clinical Practice Research Datalink primary care database. Within this population we identified cancer survivors who were alive and under follow-up at least 1 year after diagnosis, and controls with no cancer history. Follow-up time prior to cancer diagnosis was included in the control cohort. Using logistic regression, we compared these groups with respect to uptake of statins within 1 month of a first high recorded cardiovascular risk score. Then, we used Cox modelling to compare persistence on statin therapy (time to statin cessation) between cancer survivors and controls from the main study population who had initiated on a statin. RESULTS: Among 4202 cancer survivors and 113,035 controls with a record indicating a high cardiovascular risk score, 23.0% and 23.5% respectively initiated a statin within 1 month (adjusted odds ratio 0.98 [91.8-1.05], pâ=â0.626). Cancer survivors appeared more likely to discontinue statin treatment than controls (adjusted hazard ratio 1.07 [1.01-1.12], pâ=â0.02). This greater risk of discontinuing was only evident after the first year of therapy (p-interaction <â0.001). INTERPRETATION: Although cardiovascular risk is thought to be higher in cancer survivors compared to the general population, cancer survivors were no more likely to receive statins, and marginally more likely to cease long-term therapy, than general population controls. There may be an opportunity to mitigate the suspected higher cardiovascular risk in the growing population of cancer survivors by improving uptake of lipid-lowering treatment and persistence on therapy
Simulations of magnetic Bragg scattering in transmission electron microscopy
We have simulated the magnetic Bragg scattering in transmission electron
microscopy in two antiferromagnetic compounds, NiO and LaMnAsO. This weak
magnetic phenomenon was observed in NiO experimentally by Loudon. We have
computationally reproduced Loudon's experimental data, and for comparison we
have performed calculations for the LaMnAsO compound as a more challenging
case, containing lower concentration of magnetic elements and strongly
scattering heavier non-magnetic elements. We have also described thickness and
voltage dependence of the intensity of the antiferromagnetic Bragg spot for
both compounds. We have employed two computational approaches, one assuming a
static lattice with Debye-Waller smeared potentials, and another explicitly
considering the atomic vibrations within the quantum excitations of phonons
model (thermal diffuse scattering). The structural analysis shows that the
antiferromagnetic Bragg spot appears in between (111) and (000) reflections for
NiO, while for LaMnAsO the antiferromagnetic Bragg spot appears at the position
of the (110) reflection in the diffraction pattern, which corresponds to a
forbidden reflection of the crystal structure. Calculations predict that the
intensity of the magnetic Bragg spot in NiO is significantly stronger than
thermal diffuse scattering at room temperature. For LaMnAsO, the magnetic Bragg
spot is weaker than the room-temperature thermal diffuse scattering, but its
detection can be facilitated at reduced temperatures
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