| 21. |
- Abrahamsson, Maria, et al.
(författare)
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Steric influence on the excited-state lifetimes of ruthenium complexes with bipyridyl-alkanylene-pyridyl ligands.
- 2008
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Ingår i: Inorganic Chemistry. - : ACS. - 0020-1669 .- 1520-510X. ; 47:9, s. 3540-3548
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Tidskriftsartikel (refereegranskat)abstract
- The structural effect on the metal-to-ligand charge transfer (MLCT) excited-state lifetime has been investigated in bis-tridentate Ru(II)-polypyridyl complexes based on the terpyridine-like ligands [6-(2,2'-bipyridyl)](2-pyridyl)methane (1) and 2-[6-(2,2'-bipyridyl)]-2-(2-pyridyl)propane (2). A homoleptic ([Ru(2)(2)](2+)) and a heteroleptic complex ([Ru(ttpy)(2)](2+)) based on the new ligand 2 have been prepared and their photophysical and structural properties studied experimentally and theoretically and compared to the results for the previously reported [Ru(1)(2)](2+). The excited-state lifetime of the homoleptic Ru-II complex with the isopropylene-bridged ligand 2 was found to be 50 times shorter than that of the corresponding homoleptic Ru-II complex of ligand 1, containing a methylene bridge. A comparison of the ground-state geometries of the two homoleptic complexes shows that steric interactions involving the isopropylene bridges make the coordination to the central Ru-II ion less octahedral in [Ru(2)(2)](2+) than in [Ru(1)(2))(2+). Calculations indicate that the structural differences in these complexes influence their ligand field splittings as well as the relative stabilities of the triplet metal-to-ligand charge transfer ((MLCT)-M-3) and metal-centered ((MC)-M-3) excited states. The large difference in measured excited-state lifetimes for the two homoleptic Ru-II complexes is attributed to a strong influence of steric interactions on the ligand field strength, which in turn affects the activation barriers for thermal conversion from (MLCT)-M-3 states to short-lived (MC)-M-3 states.
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| 22. |
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| 23. |
- Addazi, A., et al.
(författare)
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New high-sensitivity searches for neutrons converting into antineutrons and/or sterile neutrons at the HIBEAM/NNBAR experiment at the European Spallation Source
- 2021
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Ingår i: Journal of Physics G. - : Institute of Physics Publishing (IOPP). - 0954-3899 .- 1361-6471. ; 48:7
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Tidskriftsartikel (refereegranskat)abstract
- The violation of baryon number, , is an essential ingredient for the preferential creation of matter over antimatter needed to account for the observed baryon asymmetry in the Universe. However, such a process has yet to be experimentally observed. The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source to search for baryon number violation. The program will include high-sensitivity searches for processes that violate baryon number by one or two units: free neutron–antineutron oscillation () via mixing, neutron–antineutron oscillation via regeneration from a sterile neutron state (), and neutron disappearance (n → n'); the effective process of neutron regeneration () is also possible. The program can be used to discover and characterize mixing in the neutron, antineutron and sterile neutron sectors. The experiment addresses topical open questions such as the origins of baryogenesis and the nature of dark matter, and is sensitive to scales of new physics substantially in excess of those available at colliders. A goal of the program is to open a discovery window to neutron conversion probabilities (sensitivities) by up to three orders of magnitude compared with previous searches. The opportunity to make such a leap in sensitivity tests should not be squandered. The experiment pulls together a diverse international team of physicists from the particle (collider and low energy) and nuclear physics communities, while also including specialists in neutronics and magnetics.
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| 24. |
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| 25. |
- Adell, Martin, et al.
(författare)
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Postgrowth annealing of (Ga,Mn) As under As capping: An alternative way to increase T-C
- 2005
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 86, s. 112501-
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Tidskriftsartikel (refereegranskat)abstract
- In situ postgrowth annealing of (Ga,Mn)As layers under As capping is adequate for achieving high Curie temperatures (T-C) in a similar way as ex situ annealing in air or in N-2 atmosphere practiced earlier. Thus, the first efforts give an increase of T-C from 68 to 145 K after 2 h annealing at 180 degrees C. These data, in combination with lattice parameter determinations and photoemission results, show that the As capping acts as an efficient sink for diffusing Mn interstitials.
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| 26. |
- af Hällström, Anna, 1987, et al.
(författare)
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The role of social ties in collaborative project networks: A tale of two construction cases
- 2021
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Ingår i: Construction Management and Economics. - : Informa UK Limited. - 1466-433X .- 0144-6193. ; 39:9, s. 723-738
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Tidskriftsartikel (refereegranskat)abstract
- Collaborative project delivery models (CPDMs) are increasing in popularity as infrastructure con-struction projects become more complex and grow in scale and scope. CPDMs build on highlevels of trust, information exchange and formal contractual relations, creating complex relation-ships between actors in the project network. The literature emphasizes the procurement phaseand contractual aspects of CPDMs; however, few studies explicitly focus on the role of socialrelationships in CPDM projects. Social network theory has recently been introduced in the archi-tecture, engineering and construction industry industry to study relationships between networkactors, but the role of social ties within CPDM project networks is still unclear. Through twoqualitative case studies, we have analyzed the role of social ties in projects applying a CPDMcontract. The empirical evidence of 41 semi-structured interviews and observations points toaspects that affect the development of social ties in CPDMs, such as initial project setup, projectidentification, perception of actors, resource sharing and shared space, as well as the importanceof formal and informal ties for supporting collaborative project practices. The evidence showshow social ties develop into negative or positive bonds affecting the level of collaboration. Thisstudy contributes by emphasizing the interplay between project networks using CPDMs andsocial ties.
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| 27. |
- Afroze, Shammya, 1987, et al.
(författare)
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Structure-conductivity relationship of PrBaMnMoO 6-δ through in-situ measurements: A neutron diffraction study
- 2021
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Ingår i: Ceramics International. - : Elsevier BV. - 0272-8842 .- 1873-3956. ; 47:1, s. 541-546
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Tidskriftsartikel (refereegranskat)abstract
- The structural and electrochemical properties of the double perovskite-type oxide, PrBaMnMoO6-δ, was investigated using neutron diffraction with in-situ conductivity measurement under a dry Argon atmosphere from 25 °C to 700 °C. A Rietveld refinement of the neutron diffraction data confirmed monoclinic symmetry in the P21/n space group. Rietveld refinement also confirms the unit cell parameters of a = 5.6567 (1) Å, b = 5.6065 (2) Å, c = 7.9344 (1) Å and β = 84.43° with reliable atomic positions and refinement factors (R-factors). Neutron diffraction data refinement shows two minor phases (<5%), an orthorhombic AB2O5 type phase of PrMn2O5 in the Pbam (No. 32) space group with unit cell parameters, a = 7.9672 (1) Å, b = 8.9043 (2) Å and c = 5.8540 (1) Å and a scheelite phase of BaMoO4 in the tetragonal I41/a (88) space group with the unit cell parameters, a = b = 5.9522 (1) Å, and c = 12.3211 (2) Å. Morphological images revealed a porous and intertwined microstructure. In-situ conductivity measurement shows that the total conductivity of this material was 130.84 Scm−1 at 700 °C.
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| 28. |
- Aganovic, A., et al.
(författare)
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Ventilation design conditions associated with airborne bacteria levels within the wound area during surgical procedures: a systematic review
- 2021
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Ingår i: Journal of Hospital Infection. - : Elsevier BV. - 0195-6701 .- 1532-2939. ; 113, s. 85-95
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Forskningsöversikt (refereegranskat)abstract
- Background: Without confirmation of the ventilation design conditions (typology and airflow rate), the common practice of identifying unidirectional airflow (UDAF) systems as equivalent to ultra-clean air ventilation systems may be misleading, but also any claims about the ineffectiveness of UDAF systems should be doubted. The aim of this review was to assess and compare ventilation system design conditions for which ultra-clean air (mean <10 cfu/m ) within 50 cm from the wound has been reported. Six medical databases were systematically searched to identify and select studies reporting intraoperative airborne levels expressed as cfu/m close to the wound site, and ventilation system design conditions. Available data on confounding factors such as the number of persons present in the operating room, number of door openings, and clothing material were also included. Predictors for achieving mean airborne bacteria levels within <10 cfu/m were identified using a penalized multivariate logistic regression model. Twelve studies met the eligibility criteria and were included for analysis. UDAF systems considered had significantly higher air volume flows compared with turbulent ventilation (TV) systems considered. Ultra-clean environments were reported in all UDAF-ventilated (N = 7) rooms compared with four of 11 operating rooms equipped with TV. On multivariate analysis, the total number of air exchange rates (P=0.019; odds ratio (OR) 95% confidence interval (CI): 0.66–0.96) and type of clothing material (P=0.031; OR 95% CI: 0.01–0.71) were significantly associated with achieving mean levels of airborne bacteria <10 cfu/m . High-volume UDAF systems complying with DIN 1946-4:2008 standards for the airflow rate and ceiling diffuser size unconditionally achieve ultra-clean air close to the wound site. In conclusion, the studied articles demonstrate that high-volume UDAF systems perform as ultra-clean air systems and are superior to TV systems in reducing airborne bacteria levels close to the wound site. 3 3 3 3
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| 29. |
- Aghanavesi, Somayeh, 1981-, et al.
(författare)
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A multiple motion sensors index for motor state quantification in Parkinson's disease
- 2020
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Ingår i: Computer Methods and Programs in Biomedicine. - : Elsevier BV. - 0169-2607 .- 1872-7565. ; 189
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To construct a Treatment Response Index from Multiple Sensors (TRIMS) for quantification of motor state in patients with Parkinson's disease (PD) during a single levodopa dose. Another aim was to compare TRIMS to sensor indexes derived from individual motor tasks. Method: Nineteen PD patients performed three motor tests including leg agility, pronation-supination movement of hands, and walking in a clinic while wearing inertial measurement unit sensors on their wrists and ankles. They performed the tests repeatedly before and after taking 150% of their individual oral levodopa-carbidopa equivalent morning dose.Three neurologists blinded to treatment status, viewed patients’ videos and rated their motor symptoms, dyskinesia, overall motor state based on selected items of Unified PD Rating Scale (UPDRS) part III, Dyskinesia scale, and Treatment Response Scale (TRS). To build TRIMS, out of initially 178 extracted features from upper- and lower-limbs data, 39 features were selected by stepwise regression method and were used as input to support vector machines to be mapped to mean reference TRS scores using 10-fold cross-validation method. Test-retest reliability, responsiveness to medication, and correlation to TRS as well as other UPDRS items were evaluated for TRIMS. Results: The correlation of TRIMS with TRS was 0.93. TRIMS had good test-retest reliability (ICC = 0.83). Responsiveness of the TRIMS to medication was good compared to TRS indicating its power in capturing the treatment effects. TRIMS was highly correlated to dyskinesia (R = 0.85), bradykinesia (R = 0.84) and gait (R = 0.79) UPDRS items. Correlation of sensor index from the upper-limb to TRS was 0.89. Conclusion: Using the fusion of upper- and lower-limbs sensor data to construct TRIMS provided accurate PD motor states estimation and responsive to treatment. In addition, quantification of upper-limb sensor data during walking test provided strong results. © 2019
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| 30. |
- Ahlberg, Daniel, et al.
(författare)
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Gilbert's Disc Model With Geostatistical Marking
- 2018
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Ingår i: Advances in Applied Probability. - : Cambridge University Press (CUP). - 0001-8678 .- 1475-6064. ; 50:4, s. 1075-1094
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Tidskriftsartikel (refereegranskat)abstract
- We study a variant of Gilbert's disc model, in which discs are positioned at the points of a Poisson process in R-2 with radii determined by an underlying stationary and ergodic random field phi: R-2 -> [0, infinity), independent of the Poisson process. This setting, in which the random field is independent of the point process, is often referred to as geostatistical marking. We examine how typical properties of interest in stochastic geometry and percolation theory, such as coverage probabilities and the existence of long-range connections, differ between Gilbert's model with radii given by some random field and Gilbert's model with radii assigned independently, but with the same marginal distribution. Among our main observations we find that complete coverage of R(2 )does not necessarily happen simultaneously, and that the spatial dependence induced by the random field may both increase as well as decrease the critical threshold for percolation.
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