Fine-regolith production on asteroids controlled by rock porosity.

Spacecraft missions have observed regolith blankets of unconsolidated subcentimetre particles on stony asteroids1-3. Telescopic data have suggested the presence of regolith blankets also on carbonaceous asteroids, including (101955) Bennu4 and (162173) Ryugu5. However, despite observations of processes that are capable of comminuting boulders into unconsolidated materials, such as meteoroid bombardment6,7 and thermal cracking8, Bennu and Ryugu lack extensive areas covered in subcentimetre particles7,9. Here we report an inverse correlation between the local abundance of subcentimetre particles and the porosity of rocks on Bennu. We interpret this finding to mean that accumulation of unconsolidated subcentimetre particles is frustrated where the rocks are highly porous, which appears to be most of the surface10. The highly porous rocks are compressed rather than fragmented by meteoroid impacts, consistent with laboratory experiments11,12, and thermal cracking proceeds more slowly than in denser rocks. We infer that regolith blankets are uncommon on carbonaceous asteroids, which are the most numerous type of asteroid13. By contrast, these terrains should be common on stony asteroids, which have less porous rocks and are the second-most populous group by composition13. The higher porosity of carbonaceous asteroid materials may have aided in their compaction and cementation to form breccias, which dominate the carbonaceous chondrite meteorites14.

Bennu's near-Earth lifetime of 1.75 million years inferred from craters on its boulders.

An asteroid's history is determined in large part by its strength against collisions with other objects1,2 (impact strength). Laboratory experiments on centimetre-scale meteorites3 have been extrapolated and buttressed with numerical simulations to derive the impact strength at the asteroid scale4,5. In situ evidence of impacts on boulders on airless planetary bodies has come from Apollo lunar samples6 and images of the asteroid (25143) Itokawa7. It has not yet been possible, however, to assess directly the impact strength, and thus the absolute surface age, of the boulders that constitute the building blocks of a rubble-pile asteroid. Here we report an analysis of the size and depth of craters observed on boulders on the asteroid (101955) Bennu. We show that the impact strength of metre-sized boulders is 0.44 to 1.7 megapascals, which is low compared to that of solid terrestrial materials. We infer that Bennu's metre-sized boulders record its history of impact by millimetre- to centimetre-scale objects in near-Earth space. We conclude that this population of near-Earth impactors has a size frequency distribution similar to that of metre-scale bolides and originates from the asteroidal population. Our results indicate that Bennu has been dynamically decoupled from the main asteroid belt for 1.75 ± 0.75 million years.

The unexpected surface of asteroid (101955) Bennu.

NASA'S Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer (OSIRIS-REx) spacecraft recently arrived at the near-Earth asteroid (101955) Bennu, a primitive body that represents the objects that may have brought prebiotic molecules and volatiles such as water to Earth1. Bennu is a low-albedo B-type asteroid2 that has been linked to organic-rich hydrated carbonaceous chondrites3. Such meteorites are altered by ejection from their parent body and contaminated by atmospheric entry and terrestrial microbes. Therefore, the primary mission objective is to return a sample of Bennu to Earth that is pristine-that is, not affected by these processes4. The OSIRIS-REx spacecraft carries a sophisticated suite of instruments to characterize Bennu's global properties, support the selection of a sampling site and document that site at a sub-centimetre scale5-11. Here we consider early OSIRIS-REx observations of Bennu to understand how the asteroid's properties compare to pre-encounter expectations and to assess the prospects for sample return. The bulk composition of Bennu appears to be hydrated and volatile-rich, as expected. However, in contrast to pre-encounter modelling of Bennu's thermal inertia12 and radar polarization ratios13-which indicated a generally smooth surface covered by centimetre-scale particles-resolved imaging reveals an unexpected surficial diversity. The albedo, texture, particle size and roughness are beyond the spacecraft design specifications. On the basis of our pre-encounter knowledge, we developed a sampling strategy to target 50-metre-diameter patches of loose regolith with grain sizes smaller than two centimetres4. We observe only a small number of apparently hazard-free regions, of the order of 5 to 20 metres in extent, the sampling of which poses a substantial challenge to mission success.

Evolution in the management of aorta to left ventricular tunnel in a national congenital cardiology centre.

An aorto-ventricular tunnel is a rare congenital cardiac defect, where a channel connects the lumen of the ascending aorta to the left or right ventricle. Four patients presented with an aorto-left ventricular tunnel over two decades at a median age of 8 months (range 0.1-10 months). Two patients (50%) had associated cardiac anomalies including hypoplastic left heart syndrome and left ventricular noncompaction/hypertrophic cardiomyopathy with aortic/pulmonary valve dysplasia in one patient each. Although traditionally surgical treatment has addressed this problem, management has evolved to transcatheter closure with excellent outcomes in appropriately selected patients at our national centre.

Early Bactericidal Activity Trial of Nitazoxanide for Pulmonary Tuberculosis.

This study was conducted in treatment-naive adults with drug-susceptible pulmonary tuberculosis in Port-au-Prince, Haiti, to assess the safety, bactericidal activity, and pharmacokinetics of nitazoxanide (NTZ). This was a prospective phase II clinical trial in 30 adults with pulmonary tuberculosis. Twenty participants received 1 g of NTZ orally twice daily for 14 days. A control group of 10 participants received standard therapy over 14 days. The primary outcome was the change in time to culture positivity (TTP) in an automated liquid culture system. The most common adverse events seen in the NTZ group were gastrointestinal complaints and headache. The mean change in TTP in sputum over 14 days in the NTZ group was 3.2 h ± 22.6 h and was not statistically significant (P = 0.56). The mean change in TTP in the standard therapy group was significantly increased, at 134 h ± 45.2 h (P < 0.0001). The mean NTZ MIC for Mycobacterium tuberculosis isolates was 12.3 µg/ml; the mean NTZ maximum concentration (Cmax) in plasma was 10.2 µg/ml. Negligible NTZ levels were measured in sputum. At the doses used, NTZ did not show bactericidal activity against M. tuberculosis Plasma concentrations of NTZ were below the MIC, and its negligible accumulation in pulmonary sites may explain the lack of bactericidal activity. (This study has been registered at ClinicalTrials.gov under identifier NCT02684240.).

The role of clonal haematopoiesis in cardiovascular diseases: epidemiology and experimental studies.

Clonal haematopoiesis results from acquired mutations in haematopoietic stem and progenitor cells (HSPCs). These mutations can confer the HSPC with a competitive advantage, leading to their clonal expansion within the limiting bone marrow niche. This process is often insufficient to produce a haematologic malignancy; however, the expanding HSPC clones increasingly give rise to progeny leucocytes whose phenotypes can be altered by the somatic mutations that they harbour. Key findings from multiple human studies have shown that clonal haematopoiesis in the absence of overt haematologic alterations is common amongst the ageing population and associated with mortality and cardiovascular disease. Key findings from experimental studies have provided evidence for a causative role for clonal haematopoiesis in cardiovascular diseases, and aspects of these mechanisms have been elucidated. Whilst our understanding of the impact and biology of clonal haematopoiesis is in its infancy, analyses of some of the most commonly mutated driver genes suggest promising clinical scenarios involving the development of personalized therapies with immunomodulatory drugs that exploit the perturbation caused by the particular mutation. Herein, we review the accumulating epidemiological and experimental evidence, and summarize our current understanding of the importance of clonal haematopoiesis as a new causal risk factor for atherosclerotic cardiovascular disease and heart failure.

Leadless Micra Pacemaker Use in the Pediatric Population: Device Implantation and Short-Term Outcomes.

The development of Leadless cardiac pacemakers avoids the inherent complications that may occur secondary to lead insertion. A large number of devices have been inserted in adult patients although data in pediatric patients are lacking. We aimed to assess our experience with the Leadless device in the pediatric population. We performed a retrospective study on all pediatric patients who underwent insertion of a Leadless pacemaker in our center. Data were collected for demographic, procedural, and outcome variables. Nine patients with a median (IQR) age and weight of 13 (12-14) years and 37 (31-50) kg, respectively, were enrolled. The median (IQR) procedural time was 62 (60-65) min with insertion thresholds of 0.5 (0.35-1) Volts at 0.24 ms. All devices were successfully inserted without complication. One device was replaced with a single-lead endocardial pacemaker at 1 year for increased thresholds. Leadless pacemaker device insertion is feasible in pediatric patients. Further studies and long-term follow-up are needed to ascertain device longevity and complication rates.

Concentration and composition of bioaerosol emissions from intensive farms: Pig and poultry livestock.

Intensive farming is widespread throughout the UK and yet the health effects of bioaerosols which may be generated by these sites are currently not well researched. A scoping study was established to measure bioaerosols emitted from intensive pig (n = 3) and poultry farms (n = 3) during the period 2014-2015. The concentration of culturable mesophilic bacteria, Gram-negative bacteria, Staphylococcus spp., and fungi selecting for presumptive Aspergillus fumigatus were measured using single-stage impaction Andersen samplers, whilst endotoxin and (1 â†’ 3)-ß-D-glucan was undertaken using inhalable personal samplers. Particulate matter concentration was determined using an optical particulate monitor. Results showed that culturable bacteria, fungi, presumptive Staphylococcus aureus (confirmed only as Staphylococcus spp.) and endotoxin concentrations were elevated above background concentrations for distances of up to 250 m downwind of the source. Of all the culturable bioaerosols measured, bacteria and Staphylococcus spp. were identified as the most significant, exceeding published or proposed bioaerosol guidelines in the UK. In particular, culturable Staphylococcus spp. downwind was at least 61 times higher than background at the boundary and at least 8 times higher 70m downwind on the four farms tested. This research represents a novel dataset of intensive farm emissions within the UK. Future research should exploit the use of innovative culture-independent methods such as next generation sequencing to develop deeper insights into the make-up of microbial communities emitted from intensive farming facilities and which would better inform species of interest from a public health perspective.

AMEE Guide No. 123 - How to read studies of educational costs.

Healthcare and health professions education share many of the same problems in decision making. In both cases, there is a finite amount of resources, and so choices need to be made between alternatives. To navigate the options available requires effective decision making. Choosing one option requires consideration of its opportunity cost - the benefit forgone of the other competing options. The purpose of this abridged AMEE guide is to introduce educational decision-makers to the economic concept of cost, and how to read studies about educational costs to inform effective cost-conscious decision-making. This guide leads with a brief review of study designs commonly utilized in this field of research, followed by an overview of how study findings are commonly presented. The tutorial will then offer a four-step model for appraising and considering the results of an economic evaluation. It asks the questions: (1) Can I trust the results? (2) What are the results telling me? (3) Could the results be transferred to my context? (4) Should I change my practice?

Polypharmacy Rates among Patients over 45 years

Polypharmacy, defined as receipt of ≥5 medications in any one month, is often associated with potentially inappropriate prescribing and adverse drug interactions. High levels of polypharmacy have been observed internationally and in Ireland. The Health Service Executive Primary Care Reimbursement Services (HSE-PCRS) pharmacy claims database for the GMS eligible population was used. We conducted Chi-square tests to determine the statistical significance of perceived differences in medication use among patients aged ³ 45 years. Our results establish a national benchmark for polypharmacy in gender and various age categories in the HSE-PCRS. Of the 794,628 individuals aged ≥45 years with at least one claim in 2013, 64.3% (510,946) had polypharmacy, with higher rates among women (67.0% - 293,886 - compared to 60.8% of men - 216,444). Patients aged 45-54 years were less likely to have polypharmacy (38.6% - 69,934) compared to those aged 75 years old (82.6% - 197,565). The high levels of polypharmacy are of interest, and suggest that monitoring and evaluation of patients' medication regimes may be required to ensure appropriateness.

Commotio Cordis Caused During Hurling Game

A teenage boy had a cardiac arrest following a blow to the chest from a hurling ball (sliotar). Prompt resuscitation and automated external defibrillation enabled a full recovery. This is the first reported case of commotio cordis caused by a sliotar although it is described in other sports. Primary prevention of commotio cordis (CC) and secondary prevention of cardiac death are discussed.

Transcatheter Mitral Valve-in-Ring Implantation.

Failed surgical mitral valve repair using an annuloplasty ring has traditionally been treated with surgical valve replacement or repair1. For patients at high risk for repeat open heart surgery, placement of a trans-catheter aortic valve (i.e., TAVI valve) within the mitral ring (i.e., Mitral-Valve-in-Ring, MViR) has emerged as a novel alternative treatment strategy2-5 . We describe our experience of a failed mitral valve repair that was successfully treated with a TAVI valve delivered via the trans-septal approach, and summarise the data relating to this emerging treatment strategy.

Buccal mucosa micronuclei counts in relation to exposure to low dose-rate radiation from the Chornobyl nuclear accident and other medical and occupational radiation exposures.

BACKGROUND: Ionizing radiation is a well-known carcinogen. Chromosome aberrations, and in particular micronuclei represent an early biological predictor of cancer risk. There are well-documented associations of micronuclei with ionizing radiation dose in some radiation-exposed groups, although not all. That associations are not seen in all radiation-exposed groups may be because cells with micronuclei will not generally pass through mitosis, so that radiation-induced micronuclei decay, generally within a few years after exposure. METHODS: Buccal samples from a group of 111 male workers in Ukraine exposed to ionizing radiation during the cleanup activities at the Chornobyl nuclear power plant were studied. Samples were taken between 12 and 18 years after their last radiation exposure from the Chornobyl cleanup. The frequency of binucleated micronuclei was analyzed in relation to estimated bone marrow dose from the cleanup activities along with a number of environmental/occupational risk factors using Poisson regression adjusted for overdispersion. RESULTS: Among the 105 persons without a previous cancer diagnosis, the mean Chornobyl-related dose was 59.5 mSv (range 0-748.4 mSv). There was a borderline significant increase in micronuclei frequency among those reporting work as an industrial radiographer compared with all others, with a relative risk of 6.19 (95% CI 0.90, 31.08, 2-sided p = 0.0729), although this was based on a single person. There was a borderline significant positive radiation dose response for micronuclei frequency with increase in micronuclei per 1000 scored cells per Gy of 3.03 (95% CI -0.78, 7.65, 2-sided p = 0.1170), and a borderline significant reduction of excess relative MN prevalence with increasing time since last exposure (p = 0.0949). There was a significant (p = 0.0388) reduction in MN prevalence associated with bone X-ray exposure, but no significant trend (p = 0.3845) of MN prevalence with numbers of bone X-ray procedures. CONCLUSIONS: There are indications of increasing trends of micronuclei prevalence with Chornobyl-cleanup-associated dose, and indications of reduction in radiation-associated excess prevalence of micronuclei with time after exposure. There are also indications of substantially increased micronuclei associated with work as an industrial radiographer. This analysis adds to the understanding of the long-term effects of low-dose radiation exposures on relevant cellular structures and methods appropriate for long-term radiation biodosimetry.

Device closure of secundum atrial septal defect in a 4.5 kilogram infant: Novel use of the Amplatzer DuctOccluder II device.

Modest secundum atrial septal defects (2°ASD) may cause significant pulmonary over perfusion during infancy, particularly in conjunction with left heart obstructive lesions. Amplatzer Septal Occluders are not ideal in this setting especially given recent concerns regarding device erosion. We report the first use of the Amplatzer Duct Occluder II device (ADO2) to close a 2°ASD in a 4.5 kg infant.

First reported use of drug-eluting bioabsorbable vascular scaffold in congenital heart disease.

The aim of catheter intervention for vascular stenosis is the restoration of lumen area and optimization of distal blood flow. In pediatric practice, this has traditionally been a compromise between less effective balloon angioplasty and bare metal stent insertion with its attendant limitations of size. Bioabsorbable stents offer short-term relief of stenosis, radial support of the healing lesion, return of endothelial function and crucially, in children, the potential for long-term growth. Initial experience, in pediatric practice, with metal-based bioabsorbable stents was relatively disappointing with frequent restenosis secondary to early reabsorption. Design modifications resulting in polymer-based, drug eluting, bioabsorbable vascular scaffolds (BVS) have reportedly overcome some of these faults. We describe the first reported use of a drug eluting BVS in three patients with: (1) A newborn with severe right pulmonary artery (RPA) stensosis post repair of type two common arterial trunk. (2) A child with pulmonary atresia/ventricular septal defect (VSD) and major aorto-pulmonary collateral arteries (MAPCAs), and (3) An infant with severe left pulmonary artery (LPA) stenosis in the setting of an LPA sling.

Simulating backspatter of blood from cranial gunshot wounds using pig models.

Few studies have examined the biomechanical basis for backspatter from cranial gunshot wounds. Backspatter is material which travels against the direction of fire following ejection from a gunshot entrance wound. Our paper focuses on the use of animals for reconstructing this phenomenon. Five live pigs and several slaughtered pigs were shot using either 9 × 19 mm, 115 grain, full metal jacketed ammunition or .22 long rifle, 40 grain, lead, round-nose ammunition. A high-speed camera was used to record the entrance wound formation and backspatter. A small amount of backspattered material was produced with all targets, and blood backspatter was seen in a few cases. However, we conclude that our model provides an understanding of the phenomenon of backspatter and the physical mechanisms associated with it. The various components of the mechanism of backspatter formation are complex and overlap. The principle mechanism observed in pig cranial gunshots was the high-speed impact response of the skin overlying the skull bone. This study has also produced evidence supporting the view that backspatter can result from the splashing of superficial blood if it is already present on the skin. Subcutaneous gas effects have been demonstrated for backspatter from contact shots. There has been no clear evidence of the role of the collapse of a temporary cavity within the brain.

Pilot randomised trial of a brief intervention for comorbid substance misuse in psychiatric in-patient settings.

OBJECTIVE: This proof of principle study evaluated the effectiveness and feasibility of a brief motivational intervention, delivered in mental health in-patient settings, to improve engagement in treatment for drug and alcohol misuse. METHOD: A randomised controlled trial using concealed randomisation, blind, independent assessment of outcome at 3 months. Participants were 59 new adult admissions, to six acute mental health hospital units in one UK mental health service, with schizophrenia related or bipolar disorder diagnoses, users of community mental health services and also misusing alcohol and/or drugs. Participants were randomised to Brief Integrated Motivational Intervention (BIMI) with Treatment As Usual (TAU), or TAU alone. The BIMI took place over a 2-week period and encouraged participants to explore substance use and its impact on mental health. RESULTS: Fifty-nine in-patients (BIMI n = 30; TAU n = 29) were randomised, the BIMI was associated with a 63% relative odds increase in the primary outcome engagement in treatment [OR 1.63 (95% CI 1.01-2.65; P = 0.047)], at 3 months. Qualitative interviews with staff and participants indicated that the BIMI was both feasible and acceptable. CONCLUSION: Mental health hospital admissions present an opportunity for brief motivational interventions focussed on substance misuse and can lead to improvements in engagement.

Effectiveness of the STOPP/START (Screening Tool of Older Persons' potentially inappropriate Prescriptions/Screening Tool to Alert doctors to the Right Treatment) criteria: systematic review and meta-analysis of randomized controlled studies.

WHAT IS KNOWN AND OBJECTIVE: STOPP/START are explicit screening tools that identify potentially inappropriate prescribing in older adults. Our objective was to update our 2013 systematic review that showed limited evidence of impact, using new evidence from randomized controlled trials (RCTs) assessing clinical, humanistic and economic outcomes in older adults. METHODS: We performed a search of PubMed, EMBASE, CINAHL, Web of Science and grey literature for RCTs published in English since the previous review through June 2014. The Cochrane Risk of Bias Tool was used. We performed a meta-analysis on the effect of STOPP on potentially inappropriate medication (PIM) rates and a narrative synthesis on other outcomes. RESULTS AND DISCUSSION: Four RCTs (n = 1925 adults) from four countries were included, reporting both acute (n = 2) and long-term care (n = 2) patients. Studies differed in implementation. Two studies were judged to have low risk, and two to have moderate-to-high risk of bias in key domains. Meta-analysis found that the STOPP criteria reduced PIM rates in all four studies, but study heterogeneity (I(2) = 86·7%) prevented the calculation of a meaningful statistical summary. We found evidence that use of the criteria reduces falls, delirium episodes, hospital length-of-stay, care visits (primary and emergency) and medication costs, but no evidence of improvements in quality of life or mortality. WHAT IS NEW AND CONCLUSION: STOPP/START may be effective in improving prescribing quality, clinical, humanistic and economic outcomes. Additional research investigating these tools is needed, especially in frail elderly and community-living patients receiving primary care.

Sensitivity of predicted bioaerosol exposure from open windrow composting facilities to ADMS dispersion model parameters.

Bioaerosols are released in elevated quantities from composting facilities and are associated with negative health effects, although dose-response relationships are not well understood, and require improved exposure classification. Dispersion modelling has great potential to improve exposure classification, but has not yet been extensively used or validated in this context. We present a sensitivity analysis of the ADMS dispersion model specific to input parameter ranges relevant to bioaerosol emissions from open windrow composting. This analysis provides an aid for model calibration by prioritising parameter adjustment and targeting independent parameter estimation. Results showed that predicted exposure was most sensitive to the wet and dry deposition modules and the majority of parameters relating to emission source characteristics, including pollutant emission velocity, source geometry and source height. This research improves understanding of the accuracy of model input data required to provide more reliable exposure predictions.

Fontan fenestration closure with Amplatzer Duct Occluder II device.

OBJECTIVES: To evaluate Fontan fenestration closure using the Amplatzer Duct Occluder II device (ADO2). BACKGROUND: Fontan fenestration closure is a well established catheter intervention. A range of occlusion devices developed for other interventions have been utilized. Most of these devices, and especially the most commonly used Amplatzer Septal Occluder, are relatively bulky. The ADO2 is a low profile, flexible, and inexpensive device which seems well suited to the Fontan fenestration. METHODS: This study details retrospective review of patients undergoing Fontan fenestration closure with an ADO2 device. Outcome measures included procedural success, pre- and post-procedural differences in oxygen saturation and mean pulmonary artery pressure and complications. RESULTS: Thirteen patients were eligible for inclusion during the 34 month study period. All procedures were technically successful. There was a significant increase in oxygen saturations (Mean=+12%, P<0.01) after fenestration closure but no significant change in mean pulmonary artery pressure (Mean=+0.5 mm Hg, P=0.08). There were no procedural complications. CONCLUSION: Fontan fenestration closure with the ADO2 device is a simple, short, and cost-effective procedure. The ADO2 characteristics recommend it to occlusion of varying sizes and morphologies of Fontan fenestration.