| 1. |
- Anastasopoulos, M., et al.
(författare)
-
Multi-Grid detector for neutron spectroscopy : Results obtained on time-of-flight spectrometer CNCS
- 2017
-
Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 12:4
-
Tidskriftsartikel (refereegranskat)abstract
- The Multi-Grid detector technology has evolved from the proof-of-principle and characterisation stages. Here we report on the performance of the Multi-Grid detector, the MG.CNCS prototype, which has been installed and tested at the Cold Neutron Chopper Spectrometer, CNCS at SNS. This has allowed a side-by-side comparison to the performance of 3He detectors on an operational instrument. The demonstrator has an active area of 0.2 m2. It is specifically tailored to the specifications of CNCS. The detector was installed in June 2016 and has operated since then, collecting neutron scattering data in parallel to the He-3 detectors of CNCS. In this paper, we present a comprehensive analysis of this data, in particular on instrument energy resolution, rate capability, background and relative efficiency. Stability, gamma-ray and fast neutron sensitivity have also been investigated. The effect of scattering in the detector components has been measured and provides input to comparison for Monte Carlo simulations. All data is presented in comparison to that measured by the 3He detectors simultaneously, showing that all features recorded by one detector are also recorded by the other. The energy resolution matches closely. We find that the Multi-Grid is able to match the data collected by 3He, and see an indication of a considerable advantage in the count rate capability. Based on these results, we are confident that the Multi-Grid detector will be capable of producing high quality scientific data on chopper spectrometers utilising the unprecedented neutron flux of the ESS.
|
|
| 2. |
- Gurung, Rejina, et al.
(författare)
-
Effect of skill drills on neonatal ventilation performance in a simulated setting-observation study in Nepal
- 2019
-
Ingår i: BMC Pediatrics. - : BMC. - 1471-2431. ; 19:1
-
Tidskriftsartikel (refereegranskat)abstract
- Aim: Maintaining neonatal resuscitation skills among health workers in low resource settings will require continuous quality improvement efforts. We aimed to evaluate the effect of skill drills and feedback on neonatal resuscitation and the optimal number of skill drills required to maintain the ventilation skill in a simulated setting. Methods: An observational study was conducted for a period of 3 months in a referral hospital of Nepal. Sixty nursing staffs were trained on Helping Babies Breathe (HBB) 2.0 and daily skill drills using a high-fidelity manikin. The high-fidelity manikin had different clinical case scenarios and provided feedback as "well done" or "improvement required" based on the ventilation performance. Adequate ventilation was defined as bag-and-mask ventilation at the rate of 40-60 breaths per minute. The effective ventilation was defined as adequate ventilation with a "well done" feedback. We assessed the correlation of number skill drills and clinical case scenario with adequate ventilation rate using pearson's correlation. We assessed the correlation of number of skill dills performed by each participant with effective ventilation using Mann Whitney test. Results: Among the total of 60 nursing staffs, all of them were competent with an average score of 12.73 +/- 1.09 out of 14 (p < 0.001) on bag-and-mask ventilation skill checklist. Among the trained staff, 47 staffs participated in daily skill drills who performed a total of 331 skill drills and 68.9% of the ventilations were done adequately. Among the 47 nursing staffs who performed the skill drills, 228 (68.9%) drills were conducted at a ventilation rate of 40-60 breathes per minute. There was no correlation of the adequate ventilation with skill drill category (p = 0.88) and the level of skill performed (p = 0.28). Out of 47 participants performing the skill drills, 74.5% of them had done effective ventilation with a mean average of 8 skill drills (SD +/- 4.78) (p-value- 0.032). Conclusion: In a simulated setting, participants who had an average skill drill of 8 in 3 months had effective ventilation. We demonstrated optimal skill drill sessions for maintain the neonatal resuscitation competency. Further evaluation will be required to validate the findings in a scale up setting.
|
|
| 3. |
- Jochum, K. P., et al.
(författare)
-
MPI-DING reference glasses for in situ microanalysis: New reference values for element concentrations and isotope ratios
- 2006
-
Ingår i: Geochemistry Geophysics Geosystems. - 1525-2027. ; 7:15 Febr
-
Tidskriftsartikel (refereegranskat)abstract
- [1] We present new analytical data of major and trace elements for the geological MPI-DING glasses KL2-G, ML3B-G, StHs6/80-G, GOR128-G, GOR132-G, BM90/21-G, T1-G, and ATHO-G. Different analytical methods were used to obtain a large spectrum of major and trace element data, in particular, EPMA, SIMS, LA-ICPMS, and isotope dilution by TIMS and ICPMS. Altogether, more than 60 qualified geochemical laboratories worldwide contributed to the analyses, allowing us to present new reference and information values and their uncertainties ( at 95% confidence level) for up to 74 elements. We complied with the recommendations for the certification of geological reference materials by the International Association of Geoanalysts (IAG). The reference values were derived from the results of 16 independent techniques, including definitive ( isotope dilution) and comparative bulk ( e. g., INAA, ICPMS, SSMS) and microanalytical ( e. g., LA-ICPMS, SIMS, EPMA) methods. Agreement between two or more independent methods and the use of definitive methods provided traceability to the fullest extent possible. We also present new and recently published data for the isotopic compositions of H, B, Li, O, Ca, Sr, Nd, Hf, and Pb. The results were mainly obtained by high-precision bulk techniques, such as TIMS and MC-ICPMS. In addition, LA-ICPMS and SIMS isotope data of B, Li, and Pb are presented.
|
|
| 4. |
- Plos, M., et al.
(författare)
-
Non-Linear Analysis and Remaining Fatigue Life of Reinforced Concrete Bridges
- 2007
-
Rapport (refereegranskat)abstract
- The work provides methods for non-linear structural analysis and fatigue safety evaluation in assessment of existing railway bridges. The use of non-linear analysis leads to higher load carrying capacities, but also to improved understanding of the structural response, forming a better basis for decisions in the assessment. The methods for fatigue assessment lead to increased remaining service life of reinforced concrete railway bridges.The achievements of the work are:• Models for assessment of concrete bridges by non-linear analysis are described, and examples and general recommendations for practical application of the methods aregiven.• An overview of the effect of corrosion on the bond properties has been developed through non-linear analyses and tests found in literature. Recommendations for practical assessment of anchorage capacity in corroded railway concrete bridges are presented.• The determination of reliable in-situ material properties in old concrete bridges is described,including properties for fully probabilistic analysis. A particular aim was to develop better methods to describe development of concrete properties with age and degree of hydration.• Recommendations are given regarding re-distribution of sectional forces and moments, obtained through linear structural analysis (with FEM). In a case study, a typical slab bridge was designed using different methods, and its response evaluated through nonlinearanalyses.• A good understanding of the load-carrying mechanisms in combined bending-shear-torsion gives a possibility to make more accurate assessments than with standard code methods. Methods and examples are presented.• A state-of-the-art review of fatigue behaviour of reinforced concrete railway bridges is presented and a methodology to assess the remaining fatigue life of existing reinforced concrete bridges subjected to railway traffic is developed.
|
|
| 5. |
- Cherkashyna, Nataliia, et al.
(författare)
-
High energy particle background at neutron spallation sources and possible solutions
- 2014
-
Ingår i: International Workshop on Neutron Optics and Detectors (NOP&D 2013) 2–5 July 2013, Munich, Germany. - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 528, s. 012013-012013
-
Konferensbidrag (refereegranskat)abstract
- Modern spallation neutron sources are driven by proton beams similar to GeV energies. Whereas low energy particle background shielding is well understood for reactors sources of neutrons (similar to 20 MeV), for high energies (100s MeV to multiple GeV) there is potential to improve shielding solutions and reduce instrument backgrounds significantly. We present initial measured data on high energy particle backgrounds, which illustrate the results of particle showers caused by high energy particles from spallation neutron sources. We use detailed physics models of different materials to identify new shielding solutions for such neutron sources, including laminated layers of multiple materials. In addition to the steel and concrete, which are used traditionally, we introduce some other options that are new to the neutron scattering community, among which there are copper alloys as used in hadronic calorimeters in high energy physics laboratories. These concepts have very attractive energy absorption characteristics, and simulations predict that the background suppression could be improved by one or two orders of magnitude. These solutions are expected to be great benefit to the European Spallation Source, where the majority of instruments are potentially affected by high energy backgrounds, as well as to existing spallation sources.
|
|
| 6. |
- Fray, Nicolas, et al.
(författare)
-
High-molecular-weight organic matter in the particles of comet 67P/Churyumov–Gerasimenko
- 2016
-
Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 538:7623, s. 72-74
-
Tidskriftsartikel (refereegranskat)abstract
- The presence of solid carbonaceous matter in cometary dust was established by the detection of elements such as carbon, hydrogen, oxygen and nitrogen in particles from comet 1P/Halley1, 2. Such matter is generally thought to have originated in the interstellar medium3, but it might have formed in the solar nebula—the cloud of gas and dust that was left over after the Sun formed4. This solid carbonaceous material cannot be observed from Earth, so it has eluded unambiguous characterization5. Many gaseous organic molecules, however, have been observed6, 7, 8, 9; they come mostly from the sublimation of ices at the surface or in the subsurface of cometary nuclei8. These ices could have been formed from material inherited from the interstellar medium that suffered little processing in the solar nebula10. Here we report the in situ detection of solid organic matter in the dust particles emitted by comet 67P/Churyumov–Gerasimenko; the carbon in this organic material is bound in very large macromolecular compounds, analogous to the insoluble organic matter found in the carbonaceous chondrite meteorites11, 12. The organic matter in meteorites might have formed in the interstellar medium and/or the solar nebula, but was almost certainly modified in the meteorites’ parent bodies11. We conclude that the observed cometary carbonaceous solid matter could have the same origin as the meteoritic insoluble organic matter, but suffered less modification before and/or after being incorporated into the comet.
|
|
| 7. |
- Gurung, Rejina, et al.
(författare)
-
Effect of skill drills on neonatal ventilation performance in a simulated setting- observation study in Nepal.
- 2019
-
Ingår i: BMC pediatrics. - : Springer Science and Business Media LLC. - 1471-2431. ; 19:1
-
Tidskriftsartikel (refereegranskat)abstract
- Maintaining neonatal resuscitation skills among health workers in low resource settings will require continuous quality improvement efforts. We aimed to evaluate the effect of skill drills and feedback on neonatal resuscitation and the optimal number of skill drills required to maintain the ventilation skill in a simulated setting.An observational study was conducted for a period of 3 months in a referral hospital of Nepal. Sixty nursing staffs were trained on Helping Babies Breathe (HBB) 2.0 and daily skill drills using a high-fidelity manikin. The high-fidelity manikin had different clinical case scenarios and provided feedback as "well done" or "improvement required" based on the ventilation performance. Adequate ventilation was defined as bag-and-mask ventilation at the rate of 40-60 breaths per minute. The effective ventilation was defined as adequate ventilation with a "well done" feedback. We assessed the correlation of number skill drills and clinical case scenario with adequate ventilation rate using pearson's correlation. We assessed the correlation of number of skill dills performed by each participant with effective ventilation using Mann Whitney test.Among the total of 60 nursing staffs, all of them were competent with an average score of 12.73 ± 1.09 out of 14 (p < 0.001) on bag-and-mask ventilation skill checklist. Among the trained staff, 47 staffs participated in daily skill drills who performed a total of 331 skill drills and 68.9% of the ventilations were done adequately. Among the 47 nursing staffs who performed the skill drills, 228 (68.9%) drills were conducted at a ventilation rate of 40-60 breathes per minute. There was no correlation of the adequate ventilation with skill drill category (p = 0.88) and the level of skill performed (p = 0.28). Out of 47 participants performing the skill drills, 74.5% of them had done effective ventilation with a mean average of 8 skill drills (SD ± 4.78) (p-value- 0.032).In a simulated setting, participants who had an average skill drill of 8 in 3 months had effective ventilation. We demonstrated optimal skill drill sessions for maintain the neonatal resuscitation competency. Further evaluation will be required to validate the findings in a scale up setting.
|
|
| 8. |
- Hoogenkamp, Henk R., et al.
(författare)
-
Seamless Vascularized Large-Diameter Tubular Collagen Scaffolds Reinforced with Polymer Knittings for Esophageal Regenerative Medicine
- 2014
-
Ingår i: Tissue Engineering. Part C, Methods. - : Mary Ann Liebert Inc. - 1937-3384 .- 1937-3392. ; 20:5, s. 423-430
-
Tidskriftsartikel (refereegranskat)abstract
- A clinical demand exists for alternatives to repair the esophagus in case of congenital defects, cancer, or trauma. A seamless biocompatible off-the-shelf large-diameter tubular scaffold, which is accessible for vascularization, could set the stage for regenerative medicine of the esophagus. The use of seamless scaffolds eliminates the error-prone tubularization step, which is necessary when emanating from flat scaffolds. In this study, we developed and characterized three different types of seamless tubular scaffolds, and evaluated in vivo tissue compatibility, including vascularization by omental wrapping. Scaffolds (luminal O approximate to 1.5cm) were constructed using freezing, lyophilizing, and cross-linking techniques and included (1) single-layered porous collagen scaffold, (2) dual-layered (porous+dense) collagen scaffold, and (3) hybrid scaffold (collagen+incorporated polycaprolacton knitting). The latter had an ultimate tensile strength comparable to a porcine esophagus. To induce rapid vascularization, scaffolds were implanted in the omentum of sheep using a wrapping technique. After 6 weeks of biocompatibility, vascularization, calcification, and hypoxia were evaluated using immunohistochemistry. Scaffolds were biocompatible, and cellular influx and ingrowth of blood vessels were observed throughout the whole scaffold. No calcification was observed, and slight hypoxic conditions were detected only in the direct vicinity of the polymer knitting. It is concluded that seamless large-diameter tubular collagen-based scaffolds can be constructed and vascularized in vivo. Such scaffolds provide novel tools for esophageal reconstruction.
|
|
| 9. |
- McIsaac, R.S., et al.
(författare)
-
Directed evolution of a far-red fluorescent rhodopsin
- 2014
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 111:36, s. 13034-13039
-
Tidskriftsartikel (refereegranskat)abstract
- Microbial rhodopsins are a diverse group of photoactive transmembrane proteins found in all three domains of life. A member of this protein family, Archaerhodopsin-3 (Arch) of halobacterium Halorubrum sodomense, was recently shown to function as a fluorescent indicator of membrane potential when expressed in mammalian neurons. Arch fluorescence, however, is very dim and is not optimal for applications in live-cell imaging. We used directed evolution to identify mutations that dramatically improve the absolute brightness of Arch, as confirmed biochemically and with livecell imaging (in Escherichia coli and human embryonic kidney 293 cells). In some fluorescent Arch variants, the pKaof the protonated Schiff-base linkage to retinal is near neutral pH, a useful feature for voltage-sensing applications. These bright Arch variants enable labeling of biological membranes in the far-red/infrared and exhibit the furthest red-shifted fluorescence emission thus far reported for a fluorescent protein (maximal excitation/emission at ∼620 nm/730 nm).
|
|
