127 research outputs found
Management of Radiation Induced, Bilateral Primary THA Loosening with an Aseptic Paprosky Type IIB Acetabular Defect and a Contralateral Septic Type IIIB Acetabular Defect: A Case Report and Review of Literature
INTRODUCTION: Primary THA in an irradiated hip poses risk for early loosening and inadequate ingrowth. Adverse effects such as decreased vascularity and increased infection risk pose a threat.
CASE PRESENTATION: Our patient was a case of post-irradiation (for cervical cancer) bilateral THA loosening causing aseptic acetabular loosening on one side and catastrophic septic loosening with a Paprosky type IIIB acetabular defect with pelvic discontinuity on the contralateral side.
DISCUSSION: There have been various studies documenting deleterious effects of irradiation on osseoin-tegration and provide a challenge for long-term implant stability in THA patients.
CONCLUSION: A meticulous treatment protocol with contemporary implant technology and staged bilateral stepwise management can lead to satisfactory clinical outcomes.This case report highlights on such specific nuances and principles
The use of a selective saturation pulse to suppress t1 noise in two-dimensional 1H fast magic angle spinning solid-state NMR spectroscopy
A selective saturation pulse at fast magic angle spinning (MAS) frequencies (60+ kHz) suppresses t1 noise in the indirect dimension of two-dimensional 1H MAS NMR spectra. The method is applied to a synthetic nucleoside with an intense methyl 1H signal due to triisopropylsilyl (TIPS) protecting groups. Enhanced performance in terms of suppressing the methyl signal while minimising the loss of signal intensity of nearby resonances of interest relies on reducing spin diffusion – this is quantified by comparing two-dimensional 1H NOESY-like spin diffusion spectra recorded at 30 to 70 kHz MAS. For a saturation pulse centred at the methyl resonance, the effect of changing the nutation frequency at different MAS frequencies as well as the effect of changing the pulse duration is investigated. By applying a pulse of duration 30 ms and nutation frequency 725 Hz at 70 kHz MAS, a good compromise of significant suppression of the methyl resonance combined with the signal intensity of resonances greater than 5 ppm away from the methyl resonance being largely unaffected is achieved. The effectiveness of using a selective saturation pulse is demonstrated for both homonuclear 1H – 1H double quantum (DQ)/ single quantum (SQ) MAS and 14N – 1H heteronuclear multiple quantum coherence (HMQC) two-dimensional solid-state NMR experiments
The Influence of Lath, Block and Prior Austenite Grain (PAG) Size on the Tensile, Creep and Fatigue Properties of Novel Maraging Steel
The influence of martensitic microstructure and prior austenite grain (PAG) size on the mechanical properties of novel maraging steel was studied. This was achieved by looking at two different martensitic structures with PAG sizes of approximately 40 µm and 80 µm, produced by hot rolling to different reductions. Two ageing heat-treatments were considered: both heat-treatments consisted of austenisation at 960 °C, then aging at 560 °C for 5 h, but while one was rapidly cooled the other was slow cooled and then extended aged at 480 °C for 64 h. It is shown that for the shorter ageing treatment the smaller PAG size resulted in significant improvements in strength (increase of more than 150 MPa), ductility (four times increase), creep life (almost four times increase in creep life) and fatigue life (almost doubled). Whereas, the extended aged sample showed similar changes in the fatigue life, elongation and hardness it displayed yet showed no difference in tensile strength and creep. These results display the complexity of microstructural contributions to mechanical properties in maraging steels
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Direct Evidence for Aligned Binding of Cellulase Enzymes to Cellulose Surfaces
The conversion of biomass into green fuels and chemicals is of great societal interest. Engineers have been designing new cellulase enzymes for the breakdown of otherwise insoluble cellulose materials. A barrier to the rational design of new enzymes has been our lack of a molecular picture of how cellulase binding occurs. A critical factor is the attachment via the enzyme’s carbohydrate binding module (CBM). To elucidate the structural and mechanistic details of cellulase adsorption, we have combined experimental data from sum frequency generation spectroscopy with molecular dynamics simulations to probe the equilibrium structure and surface alignment of a 14-residue peptide mimicking the CBM. The data show that binding is driven by hydrogen bonding and that tyrosine side chains within the CBM align the cellulase with the registry of the cellulose surface. Such an alignment is favorable for the translocation and effective cellulose breakdown and is therefore likely an important parameter for the design of novel enzymes.
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Probing the Halo From the Solar Vicinity to the Outer Galaxy: Connecting Stars in Local Velocity Structures to Large-Scale Clouds
(Abridged) This paper presents the first connections made between two local
features in velocity-space found in a survey of M giant stars and stellar
spatial inhomogeneities on global scales. Comparison to cosmological,
chemodynamical stellar halo models confirm that the M giant population is
particularly sensitive to rare, recent and massive accretion events. These
events can give rise to local observed velocity sequences - a signature of a
small fraction of debris from a common progenitor, passing at high velocity
through the survey volume, near the pericenters of their eccentric orbits. The
majority of the debris is found in much larger structures, whose morphologies
are more cloud-like than stream-like and which lie at the orbital apocenters.
Adopting this interpretation, the full-space motions represented by the
observed velocity features are derived under the assumption that the members
within each sequence share a common velocity. Orbit integrations are then used
to trace the past and future trajectories of these stars across the sky
revealing plausible associations with large, previously-discovered, cloud-like
structures. The connections made between nearby velocity structures and these
distant clouds represent preliminary steps towards developing coherent maps of
such giant debris systems. These maps promise to provide new insights into the
origin of debris clouds, new probes of Galactic history and structure, and new
constraints on the high-velocity tails of the local dark matter distribution
that are essential for interpreting direct detection experiments.Comment: submitted to the Astrophysical Journal, 40 pages, 13 figure
A systematic review and meta-analysis of the effect of dispatcher-assisted CPR on outcomes from sudden cardiac arrest in adults and children
Background: Dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) has been reported in individual studies to significantly increase the rate of bystander CPR and survival from cardiac arrest. Methods: We undertook a systematic review and meta-analysis to evaluate the impact of DA-CPR programs on key clinical outcomes following out-of-hospital cardiac arrest. We searched the PubMED, EMBASE, CINAHL, ERIC and Cochrane Central Register of Controlled Trials databases from inception until July 2018. Eligible studies compared systems with and without dispatcher-assisted CPR programs. The results of included studies were classified into 3 categories for the purposes of more accurate analysis: comparison of outcomes in systems with DA-CPR programs, case-based comparison of DA-CPR to bystander CPR, and case-based comparisons of DA-CPR to no CPR before EMS arrival. The GRADE system was used to assess certainty of evidence at an outcome level. We used random-effects models to produce summary effect sizes across all outcomes. Results: Of 5531 citations screened, 33 studies were eligible for inclusion. All included studies were observational. Evidence certainty across all outcomes was assessed as low or very low. In system-level and patient-level comparisons, the provision of DA-CPR compared with no DA-CPR was consistently associated with improved outcome across all analyses. Comparison of DA-CPR to bystander CPR produced conflicting results. Findings were consistent across sensitivity analyses and the pediatric sub-group. Conclusion: These results support the recommendation that dispatchers provide CPR instructions to callers for adults and children with suspected OHCA. Review registration: PROSPERO- CRD42018091427
Efficient Genetic Method for Establishing Drosophila Cell Lines Unlocks the Potential to Create Lines of Specific Genotypes
Analysis of cells in culture has made substantial contributions to biological research. The versatility and scale of in vitro manipulation and new applications such as high-throughput gene silencing screens ensure the continued importance of cell-culture studies. In comparison to mammalian systems, Drosophila cell culture is underdeveloped, primarily because there is no general genetic method for deriving new cell lines. Here we found expression of the conserved oncogene RasV12 (a constitutively activated form of Ras) profoundly influences the development of primary cultures derived from embryos. The cultures become confluent in about three weeks and can be passaged with great success. The lines have undergone more than 90 population doublings and therefore constitute continuous cell lines. Most lines are composed of spindle-shaped cells of mesodermal type. We tested the use of the method for deriving Drosophila cell lines of a specific genotype by establishing cultures from embryos in which the warts (wts) tumor suppressor gene was targeted. We successfully created several cell lines and found that these differ from controls because they are primarily polyploid. This phenotype likely reflects the known role for the mammalian wts counterparts in the tetraploidy checkpoint. We conclude that expression of RasV12 is a powerful genetic mechanism to promote proliferation in Drosophila primary culture cells and serves as an efficient means to generate continuous cell lines of a given genotype
2017 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations Summary
The International Liaison Committee on Resuscitation has initiated a near-continuous review of cardiopulmonary resuscitation science that replaces the previous 5-year cyclic batch-and-queue approach process. This is the first of an annual series of International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations summary articles that will include the cardiopulmonary resuscitation science reviewed by the International Liaison Committee on Resuscitation in the previous year. The review this year includes 5 basic life support and 1 paediatric Consensuses on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. Each of these includes a summary of the science and its quality based on Grading of Recommendations, Assessment, Development, and Evaluation criteria and treatment recommendations. Insights into the deliberations of the International Liaison Committee on Resuscitation task force members are provided in Values and Preferences sections. Finally, the task force members have pri-oritised and listed the top 3 knowledge gaps for each population, intervention, comparator, and outcome question. (C) 2017 European Resuscitation Council and American Heart Association, Inc. Published by Elsevier B.V. All rights reserved.Peer reviewe
The effect of alternative methods of cardiopulmonary resuscitation — Cough CPR, percussion pacing or precordial thump — on outcomes following cardiac arrest. A systematic review
Background
Cardiopulmonary resuscitation (CPR) improves cardiac arrest survival. Cough CPR, percussion pacing and precordial thump have been reported as alternative CPR techniques. We aimed to summarise in a systematic review the effectiveness of these alternative CPR techniques.
Methods
We searched Ovid MEDLINE, EMBASE and the Cochrane Library on 24/08/2020. We included randomised controlled trials, observational studies and case series with five or more patients. Two reviewers independently reviewed title and abstracts to identify studies for full-text review, and reviewed bibliographies and ‘related articles’ (using PubMed) of full-texts for further eligible studies. We extracted data and performed risk-of-bias assessments on studies included in the systematic review. We summarised data in a narrative synthesis, and used GRADE to assess evidence certainty.
Results
We included 23 studies (cough CPR n = 4, percussion pacing n = 4, precordial thump n = 16; one study studied two interventions). Only two (both precordial thump) had a comparator group (‘standard’ CPR). For all techniques evidence certainty was very low. Available evidence suggests that precordial thump does not improve survival to hospital discharge in out-of-hospital cardiac arrest. The review did not find evidence that cough CPR or percussion pacing improve clinical outcomes following cardiac arrest.
Conclusion
Cough CPR, percussion pacing and precordial thump should not be routinely used in established cardiac arrest. In specific inpatient, monitored settings cough CPR (in conscious patients) or percussion pacing may be attempted at the onset of a potential lethal arrhythmia. These must not delay standard CPR efforts in those who lose cardiac output
JASMINE: Near-infrared astrometry and time-series photometry science
The Japan Astrometry Satellite Mission for INfrared Exploration (JASMINE) is a planned M-class science space mission by the Institute of Space and Astronautical Science, the Japan Aerospace Exploration Agency. JASMINE has two main science goals. One is Galactic archaeology with a Galactic Center survey, which aims to reveal the Milky Way’s central core structure and formation history from Gaia-level (∼25 as) astrometry in the near-infrared (NIR) Hw band (1.0–1.6 m). The other is an exoplanet survey, which aims to discover transiting Earth-like exoplanets in the habitable zone from NIR time-series photometry of M dwarfs when the Galactic Center is not accessible. We introduce the mission, review many science objectives, and present the instrument concept. JASMINE will be the first dedicated NIR astrometry space mission and provide precise astrometric information on the stars in the Galactic Center, taking advantage of the significantly lower extinction in the NIR. The precise astrometry is obtained by taking many short-exposure images. Hence, the JASMINE Galactic Center survey data will be valuable for studies of exoplanet transits, asteroseismology, variable stars, and microlensing studies, including discovery of (intermediate-mass) black holes. We highlight a swath of such potential science, and also describe synergies with other missions
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