Angular momentum generation in nuclear fission.

When a heavy atomic nucleus splits (fission), the resulting fragments are observed to emerge spinning1; this phenomenon has been a mystery in nuclear physics for over 40 years2,3. The internal generation of typically six or seven units of angular momentum in each fragment is particularly puzzling for systems that start with zero, or almost zero, spin. There are currently no experimental observations that enable decisive discrimination between the many competing theories for the mechanism that generates the angular momentum4-12. Nevertheless, the consensus is that excitation of collective vibrational modes generates the intrinsic spin before the nucleus splits (pre-scission). Here we show that there is no significant correlation between the spins of the fragment partners, which leads us to conclude that angular momentum in fission is actually generated after the nucleus splits (post-scission). We present comprehensive data showing that the average spin is strongly mass-dependent, varying in saw-tooth distributions. We observe no notable dependence of fragment spin on the mass or charge of the partner nucleus, confirming the uncorrelated post-scission nature of the spin mechanism. To explain these observations, we propose that the collective motion of nucleons in the ruptured neck of the fissioning system generates two independent torques, analogous to the snapping of an elastic band. A parameterization based on occupation of angular momentum states according to statistical theory describes the full range of experimental data well. This insight into the role of spin in nuclear fission is not only important for the fundamental understanding and theoretical description of fission, but also has consequences for the γ-ray heating problem in nuclear reactors13,14, for the study of the structure of neutron-rich isotopes15,16, and for the synthesis and stability of super-heavy elements17,18.

Advances in the Direct Study of Carbon Burning in Massive Stars.

The ^{12}C+^{12}C fusion reaction plays a critical role in the evolution of massive stars and also strongly impacts various explosive astrophysical scenarios. The presence of resonances in this reaction at energies around and below the Coulomb barrier makes it impossible to carry out a simple extrapolation down to the Gamow window-the energy regime relevant to carbon burning in massive stars. The ^{12}C+^{12}C system forms a unique laboratory for challenging the contemporary picture of deep sub-barrier fusion (possible sub-barrier hindrance) and its interplay with nuclear structure (sub-barrier resonances). Here, we show that direct measurements of the ^{12}C+^{12}C fusion cross section may be made into the Gamow window using an advanced particle-gamma coincidence technique. The sensitivity of this technique effectively removes ambiguities in existing measurements made with gamma ray or charged-particle detection alone. The present cross-section data span over 8 orders of magnitude and support the fusion-hindrance model at deep sub-barrier energies.

Diabetic charcot neuroarthropathy: prevalence, demographics and outcome in a regional referral centre.

BACKGROUND: Diabetic Charcot neuroarthropathy (DCN) is a devastating complication for people with diabetes mellitus. The failure to diagnose DCN and institute treatment in the acute phase leads to permanent deformity and significant morbidity. There is a paucity of data on the prevalence and characteristics of patients who have developed this complication of diabetes. AIMS: To determine the prevalence, clinical characteristics and outcomes of patients with DCN from 2006 to 2012. METHODS: Case finding was performed by searching three independent lists for the period 2006-2012 including: SYNGO radiology database, HIPE database of hospital discharges, and, combined list from podiatry, endocrinology, vascular surgery and orthopaedic clinics. A consensus meeting with chart review was undertaken to confirm diagnosis of DCN. A proforma was completed from chart review to determine clinical characteristics, initial treatment and outcomes for patients with DCN. RESULTS: Forty cases of DCN were identified, resulting in an estimated period prevalence of 0.3 %. The majority of patients were male (68 %); most patients had T2DM (73 %). Mean ± SD for age was 58 ± 10 years and mean duration of diabetes was 15 ± 9 years. In the acute phase of DCN, offloading was performed in 50 %. Bisphosphonates were administered to 5 % and surgery undertaken in 5 % of cases. 38 % of patients developed subsequent foot ulceration and 20 % required amputation. CONCLUSIONS: This is the first prevalence estimate of DCN in Ireland. These data suggest diagnosis of DCN is missed in the acute phase. There exists a significant risk of diabetic foot ulceration and amputation with DCN.

Trends in blindness due to diabetic retinopathy among adults aged 18-69years over a decade in Ireland.

AIMS: To describe trends in the incidence of visual impairment and blindness due to diabetic retinopathy among adults aged 18-69years in Ireland between 2004 and 2013. METHODS: Data on visual impairment due to diabetic retinopathy in adults aged 18-69years or over who are registered with the National Council for the Blind of Ireland, (2004-2013) were analysed. Annual incidence rates were calculated for the adult population and the population with diagnosed diabetes. Poisson regression was used to test for changes in rates over time. The relative, attributable and population risk of blindness and visual impairment due to diabetic retinopathy were calculated for 2013. RESULTS: Over the decade, the prevalence of diagnosed diabetes increased from 2.1% to 3.6%. Among people with diagnosed diabetes, the incidence of visual impairment due to diabetic retinopathy increased from 6.4 (95% CI 2.4-13.9) per 100,000 in 2004 to 11.7 (95% CI 5.9-21.0) per 100,000 in 2013. The incidence of blindness due to diabetic retinopathy varied from 31.9 per 100,000 (95% CI 21.6-45.7) in 2004 to 14.9 per 100,000 (95% CI 8.2-25.1) in 2013. CONCLUSIONS: Our findings indicate the need for increased attention to preventive measures for microvascular complications among adults with diabetes in Ireland. Retinopathy screening has been standardised in Ireland, these findings provide useful baseline statistics to monitor the impact of this population-based screening programme.

The impact of initial antidiabetic agent and use of monitoring agents on prescription costs in newly treated type 2 diabetes: A retrospective cohort analysis.

AIMS: To measure the costs associated with the use of antidiabetic agents, monitoring materials and cardiovascular disease (CVD) agents in the management of newly treated type 2 diabetes, and to investigate the factors associated with these costs. METHODS: A population-based retrospective cohort study was conducted using the Irish national pharmacy claims database. Newly treated patients were identified for 2012 and followed for one year post treatment initiation. Factors associated with costs were assessed using a generalised linear model with gamma family and log-link function. Cost ratios (CR) and 95% CIs were used to determine the contributors of prescription costs. Adjusted odd ratios (OR) and 95% CIs were used to investigate factors associated with high frequency self-monitoring of blood glucose (SMBG). RESULTS: Mean prescription costs for the 12,941 subjects was €871, while total costs were €11 million. CVD agents accounted for 58% of total costs; 22% of costs were for SMBG; antidiabetic agents accounted for 17% of costs. SMBG resulted in costs that were 80% higher than those without, CR 1.80 (95% CI 1.76-1.84). No significant differences were observed between initiation on metformin or sulphonylureas and high frequency SMBG (OR 1.01 95% CI 0.97-1.04 vs reference). Initiation on newer antidiabetic agents was a significant positive predictors of prescription costs (CR 2.36 95% CI 2.21-2.51 vs metformin). CONCLUSIONS: Type of initial antidiabetic agent, and SMBG were significant predictors of prescription costs. SMBG represent a major proportion of total costs; however, its use in combination with antidiabetic agents that do not cause hypoglycaemia is questionable.

The prevalence of Type 2 diabetes and related complications in a nationally representative sample of adults aged 50 and over in the Republic of Ireland.

AIM: To investigate the prevalence of diagnosed Type 2 diabetes and its related complications in a nationally representative sample of older adults in the Republic of Ireland. METHODS: Cross-sectional analysis of a population-based sample of adults aged ≥ 50 years from the first wave of The Irish Longitudinal Study on Ageing (TILDA), (2009-2011). Diagnosed Type 2 diabetes prevalence was estimated by self-report or the use of oral hypoglycaemic agents. The prevalence of microvascular and macrovascular complications was determined by self-report. RESULTS: Diagnosed Type 2 diabetes prevalence was 8.4% [95% confidence interval (CI): 7.8-9.0%] and was higher among men [10.3% (95% CI: 9.4-11.2%)] than women [6.6% (95% CI: 5.9-7.5%)]; P ≤ 0.001. Among participants with diagnosed Type 2 diabetes, the overall prevalence of microvascular complications was 26.0% (95% CI: 22.4-30.0%) with no evidence of gender-specific differences (P = 0.7). The overall prevalence of macrovascular complications was 15.1% (95% CI: 12.2-18.4%) and was higher among men [17.8% (95% CI: 14.3-23.1%)] than women [11.4% (95% CI: 7.7-16.4%)]; P ≤ 0.001. CONCLUSIONS: In the absence of a national diabetes register, these findings provide a robust estimate of the national prevalence of diagnosed Type 2 diabetes and level of complications among adults aged 50 years and over in Ireland.

High saturated-fat and low-fibre intake: a comparative analysis of nutrient intake in individuals with and without type 2 diabetes.

OBJECTIVE: The aim of dietary modification, as a cornerstone of type 2 diabetes (T2DM) management, is to optimise metabolic control and overall health. This study describes food and nutrient intake in a sample of adults with T2DM, and compares this to recommendations, and to intake in age, sex, body mass index (BMI) and social-class matched adults without T2DM. DESIGN: A cross-sectional analysis of food and nutrient intake in 124 T2DM individuals (64% male; age 57.4±5.6 years, BMI 32.5±5.8 kg m(-2)) and 124 adults (age 57.4±7.0 years, BMI 31.2±5.0 kg m(-2)) with no diabetes (ND) was undertaken using a 4-day semiweighed food diary. Biochemical and anthropometric variables were also measured. RESULTS: While reported energy intake was similar in T2DM vs ND (1954 vs 2004 kcal per day, P=0.99), T2DM subjects consumed more total-fat (38.8% vs 35%, P0.001), monounsaturated-fat (13.3% vs 12.2%; P=0.004), polyunsaturated-fat (6.7% vs 5.9%; P<0.001) and protein (18.6% vs 17.5%, P0.01). Both groups exceeded saturated-fat recommendations (14.0% vs 13.8%). T2DM intakes of carbohydrate (39.5% vs 42.9%), non-milk sugar (10.4% vs 15.0%) and fibre (14.4 vs 18.9 g) were significantly lower (P<0.001). Dietary glycaemic load (GL) was also lower in T2DM (120.8 vs 129.2; P=0.02), despite a similar glycaemic index (59.7 vs 60.1; P=0.48). T2DM individuals reported consuming significantly more wholemeal/brown/wholegrain breads, eggs, oils, vegetables, meat/meat products, savoury snacks and soups/sauces and less white breads, breakfast cereals, cakes/buns, full-fat dairy, chocolate, fruit juices, oily fish and alcohol than ND controls. CONCLUSION: Adults with T2DM made different food choices to ND adults. This resulted in a high saturated-fat diet, with a higher total-fat, monounsaturated-fat, polyunsaturated-fat and protein content and a lower GL, carbohydrate, fibre and non-milk sugar content. Dietary education should emphasise and reinforce the importance of higher fibre, fruit, vegetable and wholegrain intake and the substitution of monounsaturated for saturated-fat sources, in energy balanced conditions.

Patient acceptance and clinical impact of Bravo monitoring in patients with previous failed catheter-based studies.

BACKGROUND: Standard pH monitoring is performed over 24 h with a naso-oesophageal catheter (C-pH). Limitations include naso-pharyngeal discomfort, nausea and social embarrassment resulting in reduced reflux-provoking activities. Recently a catheter-free pH-monitoring technique has become available. The tolerability and diagnostic yield of this system in patients who failed standard monitoring remain unknown. AIM: To examine the tolerability and diagnostic outcome of catheter-free pH-monitoring technique in patients who failed standard monitoring. METHODS: Patients referred for C-pH and catheter-free pH monitoring completed a tolerability questionnaire. Acid exposure in the distal oesophagus and symptom index (SI) were reviewed. RESULTS: Over 4 years, 883/1751 (50%) of patients with typical reflux symptoms referred for C-pH were diagnosed with gastro-oesophageal reflux disease (GERD) based on a pathological percentage time acid exposure (%time pH <4);134 (8%) patients failed C-pH and, of these, 129 successfully completed 2-day catheter-free pH monitoring. Ninety-eight (76%) of these patients had a pathological percentage pH <4 on either day compared with 49/102 (49%) of contemporaneous C-pH patients (P < 0.01). There was no difference in SI for heartburn (35% vs. 42%; P = 0.49). The questionnaire demonstrated a preference for catheter-free pH monitoring (96%) with less restriction in activities of daily living, naso-pharyngeal discomfort, dysphagia and chest pain. CONCLUSIONS: Tolerance and satisfaction with catheter-free pH monitoring are high in patients who had previously failed C-pH; catheter-free pH monitoring assists the definitive diagnosis of GERD in this group.

Geochemistry of trace metals in a fresh water sediment: field results and diagenetic modeling.

Concentrations of Fe, Mn, Cd, Co, Ni, Pb, and Zn were determined in pore water and sediment of a coastal fresh water lake (Haringvliet Lake, The Netherlands). Elevated sediment trace metal concentrations reflect anthropogenic inputs from the Rhine and Meuse Rivers. Pore water and sediment analyses, together with thermodynamic calculations, indicate a shift in trace metal speciation from oxide-bound to sulfide-bound over the upper 20 cm of the sediment. Concentrations of reducible Fe and Mn decline with increasing depth, but do not reach zero values at 20 cm depth. The reducible phases are relatively more important for the binding of Co, Ni, and Zn than for Pb and Cd. Pore waters exhibit supersaturation with respect to Zn, Pb, Co, and Cd monosulfides, while significant fractions of Ni and Co are bound to pyrite. A multi-component, diagenetic model developed for organic matter degradation was expanded to include Zn and Ni dynamics. Pore water transport of trace metals is primarily diffusive, with a lesser contribution of bioirrigation. Reactions affecting trace metal mobility near the sediment-water interface, especially sulfide oxidation and sorption to newly formed oxides, strongly influence the modeled estimates of the diffusive effluxes to the overlying water. Model results imply less efficient sediment retention of Ni than Zn. Sensitivity analyses show that increased bioturbation and sulfate availability, which are expected upon restoration of estuarine conditions in the lake, should increase the sulfide bound fractions of Zn and Ni in the sediments.

Pulmonary hypertension in systemic sclerosis: risk factors for progression and consequences for survival.

OBJECTIVE: To assess the rate of progression of pulmonary hypertension (PHT) in systemic sclerosis (SSc) and its bearing on mortality. METHODS: A retrospective record review of 930 patients with SSc attending a specialist centre was carried out. Those at risk for both idiopathic and secondary PHT were assessed by serial Doppler echocardiography. Mortality data were reviewed. RESULTS: The cumulative prevalence of PHT was 13%. Pressures remained static in most cases. The mortality among those with a single pressure reading of 30 mmHg or higher was 20% at 20 months. An increased mortality risk was associated with high initial pressures and rising pressures. Rapid pressure rises occurred more frequently in limited than in diffuse SSC. CONCLUSIONS: The prevalence of PHT in SSc is high and the detection of PHT at any time in the disease course is associated with substantial mortality. These results demonstrate the value of echocardiographic screening for PHT in all patients with SSC.

Influence of age and anti-nerve growth factor treatment on the sympathetic and sensory innervation of the rat iris.

We have investigated alterations in the nerve supply to the iris of aged rats and the role of endogenous nerve growth factor in these changes. The overall density of nerve fibres, and the density of calcitonin gene-related peptide containing sensory nerves, were decreased by over 20% on the aged iris, as measured by computerized image analysis on immunostained preparations, while the density of sympathetic innervation was maintained. Whilst the majority of nerves supplying the iris (sympathetic, sensory and parasympathetic) are known to respond to exogenous nerve growth factor during development and in adulthood, the role of endogenous, target-derived nerve growth factor in nerve maintenance in maturity and old age awaits confirmation. Our results showed that localized treatment with anti-nerve growth factor of iridial nerve terminals did not affect sympathetic or sensory neurons in young rats, but caused a dramatic reduction of sympathetic nerve density on irides of old rats. The effect of anti-nerve growth factor treatment on the sensory innervation of old irides was less obvious. We conclude that aged sympathetic nerves are more susceptible to nerve growth factor deprivation than young ones, or than young or aged sensory neurons, perhaps as a result of reduced responsiveness to nerve growth factor with age. Since sympathetic innervation is maintained, whilst sensory innervation is decreased in the aged iris, age-related changes in innervation are unlikely to be due to altered availability of endogenous nerve growth factor.

A low-dose triphasic oral contraceptive.

Controlled clinical investigations of a three-phase, low-dose oral contraceptive combination of levonorgestrel and ethinyl estradiol were conducted at 17 sites in the United States and 60 sites in the United Kingdom. A day 1 start in cycle one with no backup contraception was used. A total of 3546 female volunteers participated in 35,036 cycles. Medication was missed in 2688 (7.7%) cycles. Nine pregnancies were reported for an uncorrected use-effectiveness rate of 0.33 per 100 woman-years. Cycle control was excellent, bleeding irregularities were minimal, and the incidence of side effects was very low. No clinically significant variations in blood pressure means or weight means were observed. Carbohydrate and lipid metabolism studies were limited to 6 months and showed minimal alterations. Subject compliance with the preparation was excellent. It is concluded that this triphasic oral contraceptive with its varying ratios of levonorgestrel and ethinyl estradiol is an effective, predictable, and well-tolerated combination oral contraceptive.