Temperature dependence of surface stress across an order-disorder transition: p(1x2)O/W(110)

Strain relaxations of a p(1x2) ordered oxygen layer on W(110) are measured as a function of temperature across the disordering transition using low-energy electron diffraction. The measured strains approach values of 0.027 in the [1-10] and -0.053 in the [001] direction. On the basis of the measured strain relaxations, we give quantitative information on temperature-dependent surface stress using the results of ab initio calculations. From the surface formation energy for different strains, determined by first-principles calculations, we estimate that surface stress changes from -1.1 for the ordered phase to -0.2N/m for the disordered one along [1-10], and from 5.1 to 3.4 N/m along [001]. Moreover, our observation that the strains scale inversely with domain size confirms that the strain relaxation takes place at the domain boundaries.Comment: 8 pages, 5 figure

Comparison of first pass bolus AIFs extracted from sequential 18F-FDG PET and DSC-MRI of mice.

Accurate kinetic modelling of in vivo physiological function using positron emission tomography (PET) requires determination of the tracer time-activity curve in plasma, known as the arterial input function (AIF). The AIF is usually determined by invasive blood sampling methods, which are prohibitive in murine studies due to low total blood volumes. Extracting AIFs from PET images is also challenging due to large partial volume effects (PVE). We hypothesise that in combined PET with magnetic resonance imaging (PET/MR), a co-injected bolus of MR contrast agent and PET ligand can be tracked using fast MR acquisitions. This protocol would allow extraction of a MR AIF from MR contrast agent concentration-time curves, at higher spatial and temporal resolution than an image-derived PET AIF. A conversion factor could then be applied to the MR AIF for use in PET kinetic analysis. This work has compared AIFs obtained from sequential DSC-MRI and PET with separate injections of gadolinium contrast agent and 18F-FDG respectively to ascertain the technique's validity. An automated voxel selection algorithm was employed to improve MR AIF reproducibility. We found that MR and PET AIFs displayed similar character in the first pass, confirmed by gamma variate fits (p<0.02). MR AIFs displayed reduced PVE compared to PET AIFs, indicating their potential use in PET/MR studies.This work was funded by an MRC studentship and travel to PSMR 2013 was funded by the EU COST action for PET/MR.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.nima.2013.08.07

Biomarkers of Systemic Inflammation in Ugandan Infants and Children Hospitalized With Respiratory Syncytial Virus Infection

Background: Optimizing outcomes in respiratory syncytial virus (RSV) pneumonia requires accurate diagnosis and determination of severity that, in resource-limited settings, is often based on clinical assessment alone. We describe host inflammatory biomarkers and clinical outcomes among children hospitalized with RSV lower respiratory tract infection (LRTI) in Uganda and controls with rhinovirus and pneumococcal pneumonia. Methods: 58 children hospitalized with LRTI were included. We compared 37 patients with RSV, 10 control patients with rhinovirus and 11 control patients with suspected pneumococcal pneumonia. Results: Patients in the RSV group had significantly lower levels of C-reactive protein (CRP) and chitinase-3-like protein 1 (CHI3L1) than the pneumococcal pneumonia group (P < 0.05 for both). Among children with RSV, higher admission levels of CRP predicted prolonged time to resolution of tachypnea, tachycardia and fever. Higher levels of CHI3L1 were associated with higher composite clinical severity scores and predicted prolonged time to resolution of tachypnea and tachycardia, time to wean oxygen and time to sit. Higher levels of lipocalin-2 (LCN2) predicted prolonged time to resolution of tachypnea, tachycardia and time to feed. Higher admission levels of all 3 biomarkers were predictive of a higher total volume of oxygen administered during hospitalization (P < 0.05 for all comparisons). Of note, CHI3L1 and LCN2 appeared to predict clinical outcomes more accurately than CRP, the inflammatory biomarker most widely used in clinical practice. Conclusions: Our findings suggest that CHI3L1 and LCN2 may be clinically informative biomarkers in childhood RSV LRTI in low-resource settings

Solar-Powered Oxygen Delivery in Low-Resource Settings: A Randomized Clinical Noninferiority Trial

This randomized clinical noninferiority trial compares solar-powered oxygen delivery vs standard oxygen delivery using compressed oxygen cylinders among children younger than 13 years with hypoxemic illness at 2 resource-constrained hospitals in Uganda

Assessing the challenges of global long-term mitigation scenarios

The implications of global mitigation to achieve different long-term temperature goals (LTTGs) can be investigated in integrated assessment models (IAMs), which provide a large number of outputs including technology deployment levels, economic costs, carbon prices, annual rates of decarbonisation, degree of global net negative emissions required, as well as utilisation levels for fossil fuel plants. All of these factors can be considered in detail when judging the real-world feasibility of the mitigation scenarios produced by these models. This study presents a model inter-comparison of three widely used IAMs (TIAM, MESSAGE and WITCH) to analyse multiple mitigation scenarios exploring a range of LTTGs and a range of constraints, including delayed mitigation action, limited end-use electrification and delayed deployment of carbon capture technologies. The scenario outputs across the three models are examined and discussed and a matrix of the different factors concerning scenario feasibility is presented

Growth Faltering and Developmental Delay in HIV-Exposed Uninfected Ugandan Infants: A Prospective Cohort Study

BACKGROUND: HIV-exposed but uninfected (HEU) infants are at increased risk of impaired early linear growth and cognitive development. We examined associations between prenatal and postnatal growth and subsequent neurodevelopment in Ugandan HEU infants, hypothesizing that early insults may explain alterations in both somatic growth and brain development. METHODS: We prospectively followed a cohort of HEU infants from birth to 18 months of age, and measured length/height, weight, head, and arm circumference longitudinally. The Malawi Development Assessment Tool (MDAT, 12 and 18 months) and the Color Object Association Test (18 months) were used for developmental assessments. RESULTS: Among 170 HEU infants, the prevalence of low-birth weight and failure to thrive was 7.6% and 37%, respectively. HEU infants had MDAT scores that were similar to the reference population. The mean (SD) score on the Color Object Association Test was 5.5 (3.1) compared with 6.9 (5.3) in developmentally normal children. Developmental ability at age 18 months showed strong cross-sectional correlation with weight-for-age (ρ = 0.36, P < 0.0001), length/height-for-age (ρ = 0.41, P < 0.0001), head circumference-for-age (ρ = 0.26, P = 0.0011), and mid-upper arm circumference-for-age (ρ = 0.34, P = 0.0014). There was a statistically significant correlation between birth weight and MDAT z-score at 18 months (ρ = 0.20, P = 0.010). Failure to thrive was associated with lower MDAT z-score [median -0.13 (IQR -0.75 to +0.14) versus +0.14 (IQR -0.44 to +0.63), P = 0.042]. CONCLUSION: Growth faltering in HEU infants was associated with lower attainment of developmental milestones at age 18 months. Our findings point to a simple screening method for identifying HEU infants at risk for developmental intervention

Vascular basement membranes as pathways for the passage of fluid into and out of the brain

In the absence of conventional lymphatics, drainage of interstitial fluid and solutes from the brain parenchyma to cervical lymph nodes is along basement membranes in the walls of cerebral capillaries and tunica media of arteries. Perivascular pathways are also involved in the entry of CSF into the brain by the convective influx/glymphatic system. The objective of this study is to differentiate the cerebral vascular basement membrane pathways by which fluid passes out of the brain from the pathway by which CSF enters the brain. Experiment 1: 0.5 µl of soluble biotinylated or fluorescent Aβ, or 1 µl 15 nm gold nanoparticles was injected into the mouse hippocampus and their distributions determined at 5 min by transmission electron microscopy. Aβ was distributed within the extracellular spaces of the hippocampus and within basement membranes of capillaries and tunica media of arteries. Nanoparticles did not enter capillary basement membranes from the extracellular spaces. Experiment 2: 2 µl of 15 nm nanoparticles were injected into mouse CSF. Within 5min, groups of nanoparticles were present in the pial-glial basement membrane on the outer aspect of cortical arteries between the investing layer of pia mater and the glia limitans. The results of this study and previous research suggest that cerebral vascular basement membranes form the pathways by which fluid passes into and out of the brain but that different basement membrane layers are involved. The significance of these findings for neuroimmunology, Alzheimer's disease, drug delivery to the brain and the concept of the Virchow-Robin space are discussed

High mortality of beetle migrants along the Eastern Mediterranean Flyway

This is the final version. Available on open access from Wiley via the DOI in this recordData availability statement: The data that support the findings of this study are available in the supplementary material of this article.Migration is costly in terms of increased energy expenditure and exposure to risks encountered en route. These factors can lead to a higher mortality among migrants compared with more sedentary life history stages. Insect migrants are incredibly numerous, but as they are less conspicuous than vertebrate migrants and as migration often occurs at high altitude and over a broad front, it can be difficult to study migration-related mortality. A major source of information on migration-related mortality comes from cadavers found on the strandline following unsuccessful sea crossings. Here, we analyse strandline mortality following a 100 km crossing of open ocean along the Eastern Mediterranean Flyway from the Middle East mainland to the island of Cyprus by tens of millions of insects. All strandline recordings were of two species of beetles, the seven-spot ladybird Coccinella septempunctata and the carabid beetle Calosoma olivieri, whereas only nine individuals of C. septempunctata were caught successfully arriving with the rest of the insect assemblage over the ocean. Major strandings were associated with easterly winds, suggesting origins from the Middle East mainland, with the individuals documented as extremely weak and unable to fly or dead. Our results suggest that beetles are weaker migrants than other members of the migratory insect assemblage, with the sea crossing too far for the great majority to fly, leading to high mortality. The impact of this high mortality on the marine ecosystems is discussed.Royal Societ

Estimated Cost-effectiveness of Solar-Powered Oxygen Delivery for Pneumonia in Young Children in Low-Resource Settings

Importance: Pneumonia is the leading cause of childhood mortality worldwide. Severe pneumonia associated with hypoxemia requires oxygen therapy; however, access remains unreliable in low- and middle-income countries. Solar-powered oxygen delivery (solar-powered O2) has been shown to be a safe and effective technology for delivering medical oxygen. Examining the cost-effectiveness of this innovation is critical for guiding implementation in low-resource settings. Objective: To determine the cost-effectiveness of solar-powered O2 for treating children in low-resource settings with severe pneumonia who require oxygen therapy. Design, setting, and participants: An economic evaluation study of solar-powered O2 was conducted from January 12, 2020, to February 27, 2021, in compliance with the World Health Organization Choosing Interventions That Are Cost-Effective (WHO-CHOICE) guidelines. Using existing literature, plausible ranges for component costs of solar-powered O2 were determined in order to calculate the expected total cost of implementation. The costs of implementing solar-powered O2 at a single health facility in low- and middle-income countries was analyzed for pediatric patients younger than 5 years who required supplemental oxygen. Exposures: Treatment with solar-powered O2. Main outcomes and measures: The incremental cost-effectiveness ratio (ICER) of solar-powered O2 was calculated as the additional cost per disability-adjusted life-year (DALY) saved. Sensitivity of the ICER to uncertainties of input parameters was assessed through univariate and probabilistic sensitivity analyses. Results: The ICER of solar-powered O2 was estimated to be $20 (US dollars) per DALY saved (95$2.83-$206) relative to the null case (no oxygen). Costs of solar-powered O2 were alternatively quantified as$26 per patient treated and $542 per life saved. Univariate sensitivity analysis found that the ICER was most sensitive to the volume of pediatric pneumonia admissions and the case fatality rate. The ICER was insensitive to component costs of solar-powered O2 systems. In secondary analyses, solar-powered O2 was cost-effective relative to grid-powered concentrators (ICER$140 per DALY saved) and cost-saving relative to fuel generator-powered concentrators (cost saving of $7120). Conclusions and relevance: The results of this economic evaluation suggest that solar-powered O2 is a cost-effective solution for treating hypoxemia in young children in low- and middle-income countries, relative to no oxygen. Future implementation should prioritize sites with high rates of pediatric pneumonia admissions and mortality. This study provides economic support for expansion of solar-powered O2 and further assessment of its efficacy and mortality benefit