| 1. |
- Hellman, A, et al.
(författare)
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Predicting catalysis : understanding ammonia synthesis from first-principles calculations
- 2006
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Ingår i: Journal of Physical Chemistry B. - 1520-6106 .- 1520-5207. ; 110, s. 17719-17735
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Tidskriftsartikel (refereegranskat)abstract
- Here, we give a full account of a large collaborative effort toward an atomic-scale understanding of modern industrial ammonia production over ruthenium catalysts. We show that overall rates of ammonia production can be determined by applying various levels of theory (including transition state theory with or without tunneling corrections, and quantum dynamics) to a range of relevant elementary reaction steps, such as N(2) dissociation, H(2) dissociation, and hydrogenation of the intermediate reactants. A complete kinetic model based on the most relevant elementary steps can be established for any given point along an industrial reactor, and the kinetic results can be integrated over the catalyst bed to determine the industrial reactor yield. We find that, given the present uncertainties, the rate of ammonia production is well-determined directly from our atomic-scale calculations. Furthermore, our studies provide new insight into several related fields, for instance, gas-phase and electrochemical ammonia synthesis. The success of predicting the outcome of a catalytic reaction from first-principles calculations supports our point of view that, in the future, theory will be a fully integrated tool in the search for the next generation of catalysts.
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| 3. |
- Burstrom, G, et al.
(författare)
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Feasibility and accuracy of a robotic guidance system for navigated spine surgery in a hybrid operating room: a cadaver study
- 2020
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1, s. 7522-
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Tidskriftsartikel (refereegranskat)abstract
- The combination of navigation and robotics in spine surgery has the potential to accurately identify and maintain bone entry position and planned trajectory. The goal of this study was to examine the feasibility, accuracy and efficacy of a new robot-guided system for semi-automated, minimally invasive, pedicle screw placement. A custom robotic arm was integrated into a hybrid operating room (OR) equipped with an augmented reality surgical navigation system (ARSN). The robot was mounted on the OR-table and used to assist in placing Jamshidi needles in 113 pedicles in four cadavers. The ARSN system was used for planning screw paths and directing the robot. The robot arm autonomously aligned with the planned screw trajectory, and the surgeon inserted the Jamshidi needle into the pedicle. Accuracy measurements were performed on verification cone beam computed tomographies with the planned paths superimposed. To provide a clinical grading according to the Gertzbein scale, pedicle screw diameters were simulated on the placed Jamshidi needles. A technical accuracy at bone entry point of 0.48 ± 0.44 mm and 0.68 ± 0.58 mm was achieved in the axial and sagittal views, respectively. The corresponding angular errors were 0.94 ± 0.83° and 0.87 ± 0.82°. The accuracy was statistically superior (p < 0.001) to ARSN without robotic assistance. Simulated pedicle screw grading resulted in a clinical accuracy of 100%. This study demonstrates that the use of a semi-automated surgical robot for pedicle screw placement provides an accuracy well above what is clinically acceptable.
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| 4. |
- Cewe, P, et al.
(författare)
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Evaluation of a Novel Teleradiology Technology for Image-Based Distant Consultations: Applications in Neurosurgery
- 2021
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Ingår i: Diagnostics (Basel, Switzerland). - : MDPI AG. - 2075-4418. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- In emergency settings, fast access to medical imaging for diagnostic is pivotal for clinical decision making. Hence, a need has emerged for solutions that allow rapid access to images on small mobile devices (SMD) without local data storage. Our objective was to evaluate access times to full quality anonymized DICOM datasets, comparing standard access through an authorized hospital computer (AHC) to a zero-footprint teleradiology technology (ZTT) used on a personal computer (PC) or SMD using national and international networks at a regional neurosurgical center. Image datasets were sent to a senior neurosurgeon, outside the hospital network using either an AHC and a VPN connection or a ZTT (Image Over Globe (IOG)), on a PC or an SMD. Time to access DICOM images was measured using both solutions. The mean time using AHC and VPN was 250 ± 10 s (median 249 s (233–274)) while the same procedure using IOG took 50 ± 8 s (median 49 s (42–60)) on a PC and 47 ± 20 s (median 39 (33–88)) on a SMD. Similarly, an international consultation was performed requiring 23 ± 5 s (median 21 (16–33)) and 27 ± 1 s (median 27 (25–29)) for PC and SMD respectively. IOG is a secure, rapid and easy to use telemedicine technology facilitating efficient clinical decision making and remote consultations.
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| 5. |
- Christensen, T., et al.
(författare)
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The Nordic governments' responses to the Covid-19 pandemic: A comparative study of variation in governance arrangements and regulatory instruments
- 2023
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Ingår i: Regulation & Governance. - : Wiley. - 1748-5983 .- 1748-5991. ; 17:3, s. 658-676
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Tidskriftsartikel (refereegranskat)abstract
- Government responses to the Covid-19 pandemic in the Nordic states-Denmark, Finland, Iceland, Norway, and Sweden-exhibit similarities and differences. This article investigates the extent to which crisis policymaking diverges from normal policymaking within the Nordic countries and whether variations between the countries are associated with the role of expertise and the level of politicization. Government responses are analyzed in terms of governance arrangements and regulatory instruments. Findings demonstrate some deviation from normal policymaking within and considerable variation between the Nordic countries, as Denmark, Finland, and to some extent Norway exhibit similar patterns with hierarchical command and control governance arrangements, while Iceland, in some instances, resembles the case of Sweden, which has made use of network-based governance. The article shows that the higher the influence of experts, the more likely it is that the governance arrangement will be network-based.
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