205 research outputs found
Fission Cycling in Supernova Nucleosynthesis: Active-Sterile Neutrino Oscillations
We investigate nucleosynthesis in the supernovae post-core bounce
neutrino-driven wind environment in the presence of active-sterile neutrino
transformation. We consider active-sterile neutrino oscillations for a range of
mixing parameters: vacuum mass-squared differences of 0.1 eV^2 < dm^2 < 100
eV^2, and vacuum mixing angles of sin^2(2 theta_v) > 10^-4. We find a
consistent r-process pattern for a large range of mixing parameters that is in
rough agreement with the halo star CS 22892-052 abundances and the pattern
shape is determined by fission cycling. We find that the allowed region for the
formation of the r-process peaks overlaps the LSND and NSBL (3+1) allowed
region.Comment: 11 pages, 7 figures, Corrected Typo
Neutron capture on \u3csup\u3e130\u3c/sup\u3eSn during r-process freeze-out
We examine the role of neutron capture on 130Sn during r-process freeze-out in the neutrino-driven wind environment of the core-collapse supernova. We find that the global r-process abundance pattern is sensitive to the magnitude of the neutron capture cross section of 130Sn. The changes to the abundance pattern include not only a relative decrease in the abundance of 130Sn and an increase in the abundance of 131Sn, but also a shift in the distribution of material in the rare earth and third peak regions. © 2009 IOP Publishing Ltd
Mobile Phone-Delivered Cognitive Behavioral Therapy for Insomnia:A Randomized Waitlist Controlled Trial
Background: This study is one of the first randomized controlled trials investigating cognitive behavioral therapy for insomnia (CBT-I) delivered by a fully automated mobile phone app. Such an app can potentially increase the accessibility of insomnia treatment for the 10% of people who have insomnia. Objective: The objective of our study was to investigate the efficacy of CBT-I delivered via the Sleepcare mobile phone app, compared with a waitlist control group, in a randomized controlled trial. Methods: We recruited participants in the Netherlands with relatively mild insomnia disorder. After answering an online pretest questionnaire, they were randomly assigned to the app (n=74) or the waitlist condition (n=77). The app packaged a sleep diary, a relaxation exercise, sleep restriction exercise, and sleep hygiene and education. The app was fully automated and adjusted itself to a participant’s progress. Program duration was 6 to 7 weeks, after which participants received posttest measurements and a 3-month follow-up. The participants in the waitlist condition received the app after they completed the posttest questionnaire. The measurements consisted of questionnaires and 7-day online diaries. The questionnaires measured insomnia severity, dysfunctional beliefs about sleep, and anxiety and depression symptoms. The diary measured sleep variables such as sleep efficiency. We performed multilevel analyses to study the interaction effects between time and condition. Results: The results showed significant interaction effects (P<.01) favoring the app condition on the primary outcome measures of insomnia severity (d=–0.66) and sleep efficiency (d=0.71). Overall, these improvements were also retained in a 3-month follow-up. Conclusions: This study demonstrated the efficacy of a fully automated mobile phone app in the treatment of relatively mild insomnia. The effects were in the range of what is found for Web-based treatment in general. This supports the applicability of such technical tools in the treatment of insomnia. Future work should examine the generalizability to a more diverse population. Furthermore, the separate components of such an app should be investigated. It remains to be seen how this app can best be integrated into the current health regimens. Trial Registration: Netherlands Trial Register: NTR5560; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=5560 (Archived by WebCite at http://www.webcitation.org/6noLaUdJ4
Doctors, teach your adrenal insufficiency patients well: provide them with a European Emergency Card!
Adrenal insufficiency is a life-threatening condition requiring chronic glucocorticoid replacement therapy, as well as stress adaptation to prevent adrenal crises. To increase patients’ self-sustainability, education on how to tackle an ad renal crisis is crucial. All patients should carry the European Emergency Card
Characterisation and microleakage of a new hydrophilic fissure sealant – UltraSeal XT® hydro™
Objectives: The new hydrophilic fissure sealant, UltraSeal XT® hydro™ (Ultradent Products, USA), was characterised and its in vitro resistance to microleakage after placement on conventionally acid etched and sequentially lased and acid etched molars was investigated.
Materials and Methods: The sealant was characterised by Fourier transform infra-red spectroscopy, (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and Vickers indentation test. Occlusal surfaces of extracted human molars were either conventionally acid etched (n = 10), or sequentially acid etched and laser irradiated (n = 10). UltraSeal XT® hydro™ was applied to both groups of teeth which were then subjected to 2500 thermocycles between 5 and 55 °C prior to microleakage assessment by fuchsin dye penetration.
Results: UltraSeal XT® hydro™ is an acrylate-based sealant which achieved a degree of conversion of 50.6 ± 2.2% and a Vickers microhardness of 24.2 ± 1.5 under standard light curing (1000 mWcm-2 for 20 s). Fluoride ion release was negligible within a 14-day period. SEM and EDX analyses indicated that the sealant comprises irregular sub-micron and nano-sized silicon-, barium- and aluminium-bearing filler phases embedded within a ductile matrix. Laser preconditioning was found to significantly reduce microleakage (Mann-Whitney U test, p < 0.001). The lased teeth presented enhanced surface roughness on a 50 to 100 μm scale which caused the segregation and concentration of the filler particles at the enamel-sealant interface.
Conclusion: Laser preconditioning significantly decreased microleakage and increased enamel surface roughness which caused zoning of the filler particles at the enamel-sealant interface
Взаимосвязь ожирения и нарушений углеводного обмена с синдромом обструктивного апноэ во сне
Представлены литературные данные клинических исследований, в которых синдром обструктивного апноэ во сне (СОАС) рассматривается как фактор риска развития нарушений углеводного обмена, в том числе сахарного диабета 2−го типа. Анализируется взаимосвязь наиболее значимых факторов, влияющих на прогрессирование нарушений углеводного обмена у пациентов с СОАС. Приведен анализ данных о связи СОАС с диабетической автономной нейропатией и инсулинорезистентностью. Рассматривается возможность применения СРАР−терапии для коррекции метаболических нарушений у пациентов с сахарным диабетом.Представлено літературні дані клінічних досліджень, у яких синдром обструктивного апное під час сну (СОАС) розглянуто як фактор ризику розвитку порушень вуглеводного обміну, у тому числі цукрового діабету 2−го типу. Аналізується взаємозв'язок найбільш значущих факторів, що впливають на прогресування порушень вуглеводного обміну у пацієнтів із СОАС. Наведено аналіз даних про зв'язок СОАС із діабетичною автономною нейропатією та інсулінорезистентністю. Розглянуто можливість використання СРАР−терапії для корекції метаболічних порушень у пацієнтів із цукровим діабетом.Literature data about clinical trials, in which sleep apnea syndrome (SAS) is featured as a risk factor of carbohydrate metabolism disorders, including type 2 diabetes mellitus, are presented. Association of the most significant factors influencing the progress carbohydrate metabolism disorders in patients with SAS is analyzed. The data about the association of SAS and diabetic autonomous neuropathy and insulin resistance are featured. Possibility to use CPAP therapy for correction of metabolic disorders in patients with diabetes mellitus is discussed
Women's health groups to improve perinatal care in rural Nepal
BACKGROUND: Neonatal mortality rates are high in rural Nepal where more than 90% of deliveries are in the home. Evidence suggests that death rates can be reduced by interventions at community level. We describe an intervention which aimed to harness the power of community planning and decision making to improve maternal and newborn care in rural Nepal. METHODS: The development of 111 women's groups in a population of 86 704 in Makwanpur district, Nepal is described. The groups, facilitated by local women, were the intervention component of a randomized controlled trial to reduce perinatal and neonatal mortality rates. Through participant observation and analysis of reports, we describe the implementation of this intervention: the community entry process, the facilitation of monthly meetings through a participatory action cycle of problem identification, community planning, and implementation and evaluation of strategies to tackle the identified problems. RESULTS: In response to the needs of the group, participatory health education was added to the intervention and the women's groups developed varied strategies to tackle problems of maternal and newborn care: establishing mother and child health funds, producing clean home delivery kits and operating stretcher schemes. Close linkages with community leaders and community health workers improved strategy implementation. There were also indications of positive effects on group members and health services, and most groups remained active after 30 months. CONCLUSION: A large scale and potentially sustainable participatory intervention with women's groups, which focused on pregnancy, childbirth and the newborn period, resulted in innovative strategies identified by local communities to tackle perinatal care problems
Origin of micro-scale heterogeneity in polymerisation of photo-activated resin composites
Photo-activated resin composites are widely used in industry and medicine. Despite extensive chemical characterisation, the micro-scale pattern of resin matrix reactive group conversion between filler particles is not fully understood. Using an advanced synchrotron-based wide-field IR imaging system and state-of-the-art Mie scattering corrections, we observe how the presence of monodispersed silica filler particles in a methacrylate based resin reduces local conversion and chemical bond strain in the polymer phase. Here we show that heterogeneity originates from a lower converted and reduced bond strain boundary layer encapsulating each particle, whilst at larger inter-particulate distances light attenuation and monomer mobility predominantly influence conversion. Increased conversion corresponds to greater bond strain, however, strain generation appears sensitive to differences in conversion rate and implies subtle distinctions in the final polymer structure. We expect these findings to inform current predictive models of mechanical behaviour in polymer-composite materials, particularly at the resin-filler interface
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