246 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
The current landscape of European registries for rare endocrine conditions
Objective
To identify cross-border international registries for rare endocrine conditions that are led from Europe and to understand the extent of engagement with these registries within a network of reference centres (RCs) for rare endocrine conditions.
Methods
Database search of international registries and a survey of RCs in the European Reference Network for rare endocrine conditions (Endo-ERN) with an overall response rate of 82%.
Results
Of the 42 conditions with orphacodes currently covered within Endo-ERN, international registries exist for 32 (76%). Of 27 registries identified in the Orphanet and RD-Connect databases, Endo-ERN RCs were aware of 11 (41%). Of 21 registries identified by the RC, RD-Connect and Orphanet did not have a record of 10 (48%). Of the 29 glucose RCs, the awareness and participation rate in an international registry was highest for rare diabetes at 75 and 56% respectively. Of the 37 sex development RCs, the corresponding rates were highest for disorders of sex development at 70 and 52%. Of the 33 adrenal RCs, the rates were highest for adrenocortical tumours at 68 and 43%. Of the 43 pituitary RCs, the rates were highest for pituitary adenomas at 43 and 29%. Of the 31 genetic tumour RCs, the rates were highest for MEN1 at 26 and 9%. For the remaining conditions, awareness and participation in registries was less than 25%.
Conclusion
Although there is a need to develop new registries for rare endocrine conditions, there is a more immediate need to improve the awareness and participation in existing registries.This publication is part of the project ‘777215/EuRRECa’ which has received funding from the European Union’s Health Programme (2014–2020)
Perspectives on dialogue: Introduction to this special issue
We briefly summarize the papers in this volume, draw attention to the variety of perspectives that they bring to the subject of dialogue, identify a number of common themes, and conclude with a discussion of directions for further research
Antiproliferative effect of immunoliposomes containing 5-fluorodeoxyuridine-dipalmitate on colon cancer cells
We have investigated the antiproliferative action towards CC531 colon adenocarcinoma cells of target cell-specific immunoliposomes containing the amphiphilic dipalmitoyl derivative of 5-fluorodeoxyuridine (FUdR-dP). FUdR-dP incorporated in immunoliposomes caused a 13-fold stronger inhibition of CC531 cell growth in vitro, during a 72-h treatment, than FUdR-dP in liposomes without antibody, demonstrating that the prodrug is efficiently hydrolysed to yield the active drug, FUdR, intracellularly. The intracellular release of active FUdR was confirmed by determining the fate of H-3-labelled immunoliposomal FUdR-dP. Treatments shorter than 72 h with FUdR-dP in immunoliposomes resulted in anti-tumour activities comparable to, or even higher than, that of free FUdR. The shorter treatments reflect more closely the in vivo situation and illustrate the potential advantage of the use of immunoliposomes over non-targeted liposomal FUdR-dP or free FUdR. Association of tumour cell-specific immunoliposomes with CC531 cells was up to tenfold higher than that of liposomes without antibody or with irrelevant IgG coupled, demonstrating a specific interaction between liposomes and target cells which causes an efficient intracellular delivery of the drug. Since biochemical evidence indicates a lack of internalization or degradation of the liposomes as such; we postulate that entry of the drug most likely involves the direct transfer of the prodrug from the immunoliposome to the cell membrane during its antigen-specific interaction with the cells. followed by hydrolysis of FUdR-dP leading to relatively high intracellular FUdR-levels. In conclusion, we describe a targeted liposomal formulation for the anticancer drug FUdR, which is able to deliver the active drug to colon carcinoma cells with high efficiency, without the need for the cells to internalize the liposomes as such
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
A Virtual Agent as Vocabulary Trainer: Iconic Gestures Help to Improve Learners’ Memory Performance
An important and often laborious task in foreign language acquisition is vocabulary learning. Research has repeatedly demonstrated that performing iconic gestures together with novel words has a beneficial effect on learning performance. Can these findings be transferred onto virtual agents applied in gesture-supported vocabulary training? We present a study investigating whether iconic gestures performed by a virtual agent and imitated by learners have an impact on verbal memory for words in a foreign language. In a within-subject design we compared participants’ memory performance achieved with the help of a virtual agent and those achieved with the help of a human trainer regarding both short-term learning effects and long-term decay effects. The overall results demonstrate improved memory scores when participants learned with a virtual agent. Especially high performers could profit from gesture-supported training with a virtual agent
- …