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The favourable properties of tungsten borides for shielding the central high temperature superconductor (HTS) core of a spherical tokamak fusion power plant are modelled using the MCNP code. The objectives are to minimize the power deposition into the cooled HTS core, and to keep HTS radiation damage to acceptable levels by limiting the neutron and gamma fluxes. The shield materials compared are W2B, WB, W2B5 and WB4 along with a reactively sintered boride B0.329C0.074Cr0.024Fe0.274W0.299, monolithic W and WC. Five shield thicknesses between 253 and 670 mm were considered, corresponding to plasma major radii between 1400 and 2200 mm. W2B5 gave the most favourable results with a factor of ∼10 or greater reduction in neutron flux and gamma energy deposition as compared to monolithic W. These results are compared with layered water-cooled shields, giving the result that the monolithic shields, with moderating boron, gave comparable neutron flux and power deposition, and (in the case of W2B5) even better performance. Good performance without water-coolant has advantages from a reactor safety perspective due to the risks associated with radio-activation of oxygen. 10B isotope concentrations between 0% and 100% are considered for the boride shields. The naturally occurring 20% fraction gave much lower energy depositions than the 0% fraction, but the improvement largely saturated beyond 40%. Thermophysical properties of the candidate materials are discussed, in particular the thermal strain. To our knowledge, the performance of W2B5 is unrivalled by other monolithic shielding materials. This is partly as its trigonal crystal structure gives it higher atomic density compared with other borides. It is also suggested that its high performance depends on it having just high enough 10B content to maintain a constant neutron energy spectrum across the shield.

While lung involvement is an uncommon presentation of congenital syphilis, respiratory distress is a common leading symptom in sick newborns. We describe an infant who presented with respiratory distress thought to be secondary to congenital syphilis and discuss the findings suggestive of an etiology other than respiratory distress syndrome (RDS).

IntroductionHome non-invasive ventilation (NIV) can improve outcomes in some patients with chronic obstructive pulmonary disease (COPD) and chronic hypercapnic respiratory failure. It remains unclear how to identify which patients will benefit most from this treatment. We have assessed patient characteristics and ventilator settings, and their association with survival, in individuals with COPD referred to our home NIV serviceMethodsDatabase and case notes of patients with COPD referred to our centre for home NIV between April 2011 and January 2017 were retrospectively analysed. We compared patient characteristics and ventilator settings in those who survived ≥12 months, to those who died earlier.Results150 patients were referred for home NIV. 41 patients did not tolerate NIV and discontinued treatment. Of the 109 who used NIV, 50 were alive in July 2017. Full data was available for 87 (58%) patients. Median survival in patients who used NIV (n=73) was 14.2 months (Interquartile Range (IQR) 3.2–28.8). In patients who discontinued NIV (n=14), survival was 21 months (IQR 5.2–38.2; p=0.81). Characteristics and NIV settings in the 79 patients who used NIV are shown in Table 1.Abstract P123 Table 1Survived< 12 months (n= 30)Survived> 12 months (n= 43)P Value Age (years)71.1 (64.3–74.8)65.5 (62.4–75.3)p=0.47Number (%) Male10 (33%)24 (56%)p=0.06BMI (kg/m2)21.3 (17.2–25.3)26.1 (21 0–30.8)p=0.03Number (%) initiated after acute admission24 (80%)31 (72%)p=0.44Forced Expiratory Volume in 1 s (L)0.65 (0.44–0.85)0.82 (0.52–0.95)p=0.89Baseline pCO2 (kPa)9.9 (8.4–11.7)9.2 (8.2–10.7)p=0.33Inspiratory Positive Airway Pressure (cm H20)22 (19–28)25 (20–27)p=0.23Expiratory Positive Airway Pressure (cm H20)5 (5–6)5 (4–5)p=0.02Number (%) using NIV≥4 hours per night20 (67%)39 (90%)p=0.1Data are presented as median (Interquartile Range)Discussion109 (73%) patients with COPD and hypercapnic respiratory failure continued using NIV after set up. Our data demonstrates lower body mass index was significantly associated with surviving<12 months after starting NIV. Patients who survived more than 12 months showed a non-significant trend to be male, younger and use NIV for more than 4 hours each night at higher inspiratory pressures. An unexpected finding was that patients intolerant of NIV showed a trend to longer survival, compared to those who continued with NIV. This may be due to the small number of patients with full data, or that 50% of these patients had stable hypercapnic respiratory failure at NIV initiation, compared to 25% in the patients who used NIV.ConclusionsThese observations highlight the need for careful patient selection when considering which patients with COPD may benefit from home NIV, an awareness of the different features that may contribute to survival, and subsequent attention to ventilator settings and compliance once the treatment has begun.