1,682 research outputs found
Bacteriophage T5 gene D10 encodes a branch-migration protein
Helicases catalyze the unwinding of double-stranded nucleic acids where structure and phosphate backbone contacts, rather than nucleobase sequence, usually determines substrate specificity. We have expressed and purified a putative helicase encoded by the D10 gene of bacteriophage T5. Here we report that this hitherto uncharacterized protein possesses branch migration and DNA unwinding activity. The initiation of substrate unwinding showed some sequence dependency, while DNA binding and DNA-dependent ATPase activity did not. DNA footprinting and purine-base interference assays demonstrated that D10 engages these substrates with a defined polarity that may be established by protein-nucleobase contacts. Bioinformatic analysis of the nucleotide databases revealed genes predicted to encode proteins related to D10 in archaebacteria, bacteriophages and in viruses known to infect a range of eukaryotic organisms
Advance care planning documentation strategies; goals-of-care as an alternative to not-for-resuscitation in medical and oncology patients. A pre-post controlled study on quantifiable outcomes
Background: Health services in Tasmania, Victoria and now Western Australia are changing to goals-of-care (GOC) advance care planning (ACP) documentation strategies.
Aim: To compare the clinical impact of two different health department-sanctioned ACP documentation strategies.
Methods: A non-blinded, pre–post, controlled study over two corresponding 6-month periods in 2016 and 2017 comparing the current discretional not-for-resuscitation (NFR) with a new, inclusive GOC strategy in two medical/oncology wards at a large private hospital. Main outcomes were the uptake of ACP forms per hospitalisation and the timing between hospital admission, ACP form completion and in-patient death. Secondary outcomes included utilisation of the rapid response team (RRT), palliative and critical care services.
Results: In total, 650 NFR and 653 GOC patients underwent 1885 admissions (mean Charlson Comorbidity Index = 3.7). GOC patients had a higher uptake of ACP documentation (346 vs 150 ACP forms per 1000 admissions, P \u3c 0.0001) and a higher proportion of ACP forms completed within the first 48 h of admission (58 vs 39%, P = 0.0002) but a higher incidence of altering the initial ACP level of care (P = 0.003). All other measures, including ACP documentation within 48 h of death (P = 0.50), activation of RRT (P = 0.73) and admission to critical (P = 0.62) or palliative (P = 0.81) care services, remained similar. GOC documentation was often incomplete, with most sub-sections left blank between 74 and 87% of occasions.
Conclusion: Despite an increased uptake of the GOC form, overall use remained low, written completion was poor, and most quantitative outcomes remained statistically unchanged. Further research is required before a wider GOC implementation can be supported in Australia’s healthcare systems
Histopathological diagnoses on pleural biopsy specimens over a 15-year period at Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa: A retrospective review
Background. Pleural effusions are a common reason for presentation to healthcare facilities. Blind closed pleural biopsy can be a useful tool to diagnose their cause, especially in resource-limited settings.Objectives. To determine the aetiology, frequency and change in profile of histopathological diagnoses made at Chris Hani Baragwanath Academic Hospital (CHBAH), Johannesburg, South Africa, over the period 1 January 2001 - 31 December 2015.Methods. Pleural biopsies performed at CHBAH and analysed by histopathologists from the National Health Laboratory Service at the hospital over the study period were retrospectively reviewed by accessing reports from two databases (DISA and TrakCare). The subjects’ ages, genders, HIV status and histopathological diagnoses as well as adenosine deaminase and Ziehl-Neelsen results were recorded.Results. A total of 1 013 samples were included in the study, with 780 considered adequate for assessment. The most common diagnosis was granulomatous inflammation (48.1%, n=375), with the most common type being necrotising granulomatous inflammation (73.6%, n=276). Ten percent of biopsies (n=78) showed malignancy, most commonly adenocarcinoma, with 46.2% (n=36) metastatic and 23.1% (n=18) primary lung adenocarcinoma. The odds of being diagnosed with malignancy showed increasing statistical significance above the age of 40 years: 40 - 49 years odds ratio (OR) 8.7, 95% confidence interval (CI) 1.1 - 66.9 (p=0.038); 50 - 59 years OR 12.4, 95% CI 1.6 - 95.0 (p=0.015); ≥60 years OR 23.0, 95% CI 3.1 - 171.3 (p=0.002). HIV seropositivity was associated with lower odds of being diagnosed with malignancy compared with HIV-negative patients (OR 0.5, 95% CI 0.2 - 0.9; p=0.040), with greater odds of a ‘non-cancer’ diagnosis in HIV positive patients (including granulomatous inflammation and pleuritis (OR 2.16, 95% CI 1.03 - 4.51; p=0.040)).Conclusions. Blind closed pleural biopsy has a role to play in the diagnosis of exudative pleural effusions in resource-limited settings, particularly for patients suspected to have tuberculosis (TB) or malignancy. TB remains a common cause of exudative pleural effusions. Patients aged >40 years presenting with an exudative pleural effusion should routinely have pleural biopsy performed. However, this study showed a high frequency of inadequate specimens from closed pleural biopsy. Training in the performance of this procedure to increase diagnostic rates is recommended
Neutrinos in Non-linear Structure Formation - a Simple SPH Approach
We present a novel method for implementing massive neutrinos in N-body
simulations. Instead of sampling the neutrino velocity distribution by
individual point particles we take neutrino free-streaming into account by
treating it as an effective redshift dependent sound speed in a perfect
isothermal fluid, and assume a relation between the sound speed and velocity
dispersion of the neutrinos. Although the method fails to accurately model the
true neutrino power spectrum, it is able to calculate the total matter power
spectrum to the same accuracy as more complex hybrid neutrino methods, except
on very small scales. We also present an easy way to update the publicly
available Gadget-2 version with this neutrino approximation.Comment: 13 pages, 7 figure
Crack paths under mixed mode loading
Long fatigue cracks that initially experience mixed mode displacements usually change direction in response to cyclic elastic stresses. Eventually the cracks tend to orient themselves into a pure mode I condition, but the path that they take can be complex and chaotic. In this paper, we report on recent developments in techniques for tracking the crack path as it grows and evaluating the strength of the mixed mode crack tip stress field
Barrier Distributions as a Tool to Investigate Fusion and Fission
The recent availability of precisely measured fusion cross-sections has
enabled the extraction of a representation of the distribution of barriers
encountered during fusion. These representations, obtained from a variety of
reactions, provide a direct observation of how the structure of the fusing
nuclei changes the inter-nuclear potential landscape, thus affecting the fusion
probability. Recent experiments showing the effects of static quadrupole and
hexadecapole deformation, single-- and double-phonon states, transfer of
nucleons between two nuclei, and high lying excited states are reviewed. The
application of these concepts to the explanation of the anomalous
fission-fragment anisotropies observed following reactions with actinides is
discussed.Comment: 12 pages, To be published in the Proceedings of the NN 97 Conference,
Gatlinburg, Tennessee, June 1997 (Nucl. Phys. A
Effects of Pore Walls and Randomness on Phase Transitions in Porous Media
We study spin models within the mean field approximation to elucidate the
topology of the phase diagrams of systems modeling the liquid-vapor transition
and the separation of He--He mixtures in periodic porous media. These
topologies are found to be identical to those of the corresponding random field
and random anisotropy spin systems with a bimodal distribution of the
randomness. Our results suggest that the presence of walls (periodic or
otherwise) are a key factor determining the nature of the phase diagram in
porous media.Comment: REVTeX, 11 eps figures, to appear in Phys. Rev.
Numerical Results for Ground States of Mean-Field Spin Glasses at low Connectivities
An extensive list of results for the ground state properties of spin glasses
on random graphs is presented. These results provide a timely benchmark for
currently developing theoretical techniques based on replica symmetry breaking
that are being tested on mean-field models at low connectivity. Comparison with
existing replica results for such models verifies the strength of those
techniques. Yet, we find that spin glasses on fixed-connectivity graphs (Bethe
lattices) exhibit a richer phenomenology than has been anticipated by theory.
Our data prove to be sufficiently accurate to speculate about some exact
results.Comment: 4 pages, RevTex4, 5 ps-figures included, related papers available at
http://www.physics.emory.edu/faculty/boettcher
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