| 1. |
- Orwelius, Lotti, 1956-, et al.
(författare)
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Pre-existing disease : the most important factor for health related quality of life long-term after critical illness: a prospective, longitudinal, multicentre trial
- 2010
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Ingår i: Critical Care. - : BioMed Central. - 1364-8535 .- 1466-609X. ; 14:2
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Tidskriftsartikel (refereegranskat)abstract
- Introduction The aim of the present multicenter study was to assess long term (36 months) health related quality of life in patients after critical illness, compare ICU survivors health related quality of life to that of the general population and examine the impact of pre-existing disease and factors related to ICU care on health related quality of life. Methods Prospective, longitudinal, multicentre trial in three combined medical and surgical intensive care units of one university and two general hospitals in Sweden. By mailed questionnaires, health related quality of life was assessed at 6, 12, 24 and 36 months after the stay in ICU by EQ-5D and SF-36, and information of pre-existing disease was collected at the 6 months measure. ICU related factors were obtained from the local ICU database. Comorbidity and health related quality of life (EQ-5D; SF-36) was examined in the reference group. Among the 5306 patients admitted, 1663 were considered eligible (>24 hrs in the intensive care unit, and age ≥ 18 yrs, and alive 6 months after discharge). At the 6 month measure 980 (59%) patients answered the questionnaire. Of these 739 (75%) also answered at 12 month, 595 (61%) at 24 month, and 478 (47%) answered at the 36 month measure. As reference group, a random sample (n = 6093) of people from the uptake area of the hospitals were used in which concurrent disease was assessed and adjusted for. Results Only small improvements were recorded in health related quality of life up to 36 months after ICU admission. The majority of the reduction in health related quality of life after care in the ICU was related to the health related quality of life effects of pre-existing diseases. No significant effect on the long-term health related quality of life by any of the ICU-related factors was discernible. Conclusions A large proportion of the reduction in the health related quality of life after being in the ICU is attributable to pre-existing disease. The importance of the effect of pre-existing disease is further supported by the small, long term increment in the health related quality of life after treatment in the ICU. The reliability of the conclusions is supported by the size of the study populations and the long follow-up period.
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| 2. |
- Adman, Per, et al.
(författare)
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171 forskare: ”Vi vuxna bör också klimatprotestera”
- 2019
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Ingår i: Dagens nyheter (DN debatt). - Stockholm. - 1101-2447.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- DN DEBATT 26/9. Vuxna bör följa uppmaningen från ungdomarna i Fridays for future-rörelsen och protestera eftersom det politiska ledarskapet är otillräckligt. Omfattande och långvariga påtryckningar från hela samhället behövs för att få de politiskt ansvariga att utöva det ledarskap som klimatkrisen kräver, skriver 171 forskare i samhällsvetenskap och humaniora.
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| 3. |
- Malinowsky, Camilla, et al.
(författare)
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Differences in the use of everyday technology among persons with MCI, SCI and older adults without known cognitive impairment
- 2017
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Ingår i: International psychogeriatrics. - : Cambridge University Press. - 1041-6102 .- 1741-203X. ; 29:7, s. 1193-1200
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Tidskriftsartikel (refereegranskat)abstract
- Background: To use valid subjective reports sensible to cognitive decline is vital to identify very early signs of dementia development. Use of everyday technology (ET) has been shown to be sensitive to differentiate adults with mild cognitive impairment (MCI) from controls, but the group with subjective cognitive impairment (SCI) has not yet been examined. This study aims to investigate and compare self-perceived ability in ET use and number of ETs reported as actually used in a sample of older adults with SCI, MCI, and older adults with no known cognitive impairment, i.e. controls.Methods: Older adults with MCI (n = 29), SCI ( n = 26), and controls (n = 30) were interviewed with the short version of the Everyday Technology Use Questionnaire (S-ETUQ) to capture self-perceived ability in ET use and number of ETs used. To generate individual measures of ability to use ET, Rasch analysis was used. The measures were then compared group-wise using ANCOVA. The numbers of ETs used were compared group-wise with ANOVA.Results: Controls versus SCI and MCI differed significantly regarding ETs reported as used, but not SCI versus MCI. Similarly, in ability to use ET, controls versus SCI and MCI differed significantly but not SCI versus MCI.Conclusions: The significantly lower numbers of ETs reported as actually used and the lower ability in SCI and MCI groups compared to controls suggest that ET use is affected already in very minor cognitive decline. This indicates that self-reported ET use based on the S-ETUQ is sensitive to detect changes already in SCI.
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| 4. |
- Orwelius, Lotti, et al.
(författare)
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Physical effects of trauma and the psychological consequences of preexisting diseases account for a significant portion of the health-related quality of life patterns of former trauma patients
- 2012
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Ingår i: Journal of Trauma and Acute Care Surgery. - : Lippincott Williams & Wilkins. - 2163-0755 .- 2163-0763. ; 72:2, s. 504-512
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Tidskriftsartikel (refereegranskat)abstract
- Background: Health-related quality of life (HRQoL) is known to be significantly affected in former trauma patients. However, the underlying factors that lead to this outcome are largely unknown. In former intensive care unit (ICU) patients, it has been recognized that preexisting disease is the most important factor for the long-term HRQoL. The aim of this study was to investigate HRQoL up to 2 years after trauma and to examine the contribution of the trauma-specific, ICU-related, sociodemographic factors together with the effects of preexisting disease, and further to make a comparison with a large general population.Methods: A prospective 2-year multicenter study in Sweden of 108 injured patients. By mailed questionnaires, HRQoL was assessed at 6 months, 12 months, and 24 months after the stay in ICU by Short Form (SF)-36, and information of preexisting disease was collected from the national hospital database. ICU-related factors were obtained from the local ICU database. Comorbidity and HRQoL (SF-36) was also examined in the reference group, a random sample of 10,000 inhabitants in the uptake area of the hospitals.Results: For the trauma patients, there was a marked and early decrease in the physical dimensions of the SF-36 (role limitations due to physical problems and bodily pain). This decrease improved rapidly and was almost normalized after 24 months. In parallel, there were extensive decreases in the psychologic dimensions (vitality, social functioning, role limitations due to emotional problems, and mental health) of the SF-36 when comparisons were made with the general reference population.Conclusions: The new and important finding in this study is that the trauma population seems to have a trauma-specific HRQoL outcome pattern. First, there is a large and significant decrease in the physical dimensions of the SF-36, which is due to musculoskeletal effects and pain secondary to the trauma. This normalizes within 2 years, whereas the overall decrease in HRQoL remains and most importantly it is seen mainly in the psychologic dimensions and it is due to preexisting diseases
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| 5. |
- Orwelius, Lotti, et al.
(författare)
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Prevalence of sleep disturbances and long-term reduced health-related quality of life after critical care : a prospective multicenter cohort study
- 2008
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Ingår i: Critical care (London, England). - : Springer Science and Business Media LLC. - 1466-609X .- 1364-8535. ; 12:4, s. R97-
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: The aim of the present prospective multicenter cohort study was to examine the prevalence of sleep disturbance and its relation to the patient's reported health-related quality of life after intensive care. We also assessed the possible underlying causes of sleep disturbance, including factors related to the critical illness.METHODS: Between August 2000 and November 2003 we included 1,625 consecutive patients older than 17 years of age admitted for more than 24 hours to combined medical and surgical intensive care units (ICUs) at three hospitals in Sweden. Conventional intensive care variables were prospectively recorded in the unit database. Six months and 12 months after discharge from hospital, sleep disturbances and the health-related quality of life were evaluated using the Basic Nordic Sleep Questionnaire and the Medical Outcomes Study 36-item Short-form Health Survey, respectively. As a nonvalidated single-item assessment, the quality of sleep prior to the ICU period was measured. As a reference group, a random sample (n = 10,000) of the main intake area of the hospitals was used.RESULTS: The prevalence of self-reported quality of sleep did not change from the pre-ICU period to the post-ICU period. Intensive care patients reported significantly more sleep disturbances than the reference group (P < 0.01). At both 6 and 12 months, the main factor that affected sleep in the former hospitalised patients with an ICU stay was concurrent disease. No effects were related to the ICU period, such as the Acute Physiology and Chronic Health Evaluation score, the length of stay or the treatment diagnosis. There were minor correlations between the rate and extent of sleep disturbance and the health-related quality of life.CONCLUSION: There is little change in the long-term quality of sleep patterns among hospitalised patients with an ICU stay. This applies both to the comparison before and after critical care as well as between 6 and 12 months after the ICU stay. Furthermore, sleep disturbances for this group are common. Concurrent disease was found to be most important as an underlying cause, which emphasises that it is essential to include assessment of concurrent disease in sleep-related research in this group of patients.
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| 6. |
- Orwelius, Lotti, 1956-, et al.
(författare)
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Role of preexisting disease in patients' perceptions of health-related quality of life after intensive care.
- 2005
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Ingår i: Critical Care Medicine. - 0090-3493 .- 1530-0293. ; 33:7, s. 1557-1564
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To find out how patients perceive their health-related quality of life after they have been treated in an intensive care unit and whether preexisting disease influenced their perception. DESIGN:: Follow-up, quantitative, dual-site study. SETTING: Combined medical and surgical intensive care units of one university and one general hospital in Sweden. PATIENTS: Among the 1,938 patients admitted, 562 were considered eligible (>24 hrs in the intensive care unit, and age >18 yrs). The effect of preexisting disease was assessed by use of a large reference group, a random sample (n = 10,000) of the main intake area of the hospitals. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: During 2000-2002, data were collected from the intensive care unit register and from a questionnaire mailed to the patients 6 months after their discharge from hospital. Subjects in the reference group were sent postal questionnaires during 1999. Of the patients in the intensive care unit group, 74% had preexisting diseases compared with 51% in the reference group. Six months after discharge, health-related quality of life was significantly lower among patients than in the reference group. When comparisons were restricted to the previously healthy people in both groups, the observed differences were about halved, and when we compared the patients in the intensive care unit who had preexisting diseases with subjects in the reference group who had similar diseases, we found little difference in perceived health-related quality of life. In some dimensions of health-related quality of life, we found no differences between patients in the intensive care unit and the subjects in the reference population. CONCLUSIONS: Preexisting diseases significantly affect the extent of the decline of health-related quality of life after critical care, and this effect may have been underestimated in the past. As most patients who are admitted to an intensive care unit have at least one preexisting disease, it is important to account for these effects when examining outcome.
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| 7. |
- Ahlgren, Ewa, et al.
(författare)
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Driving performance of patients with coronary artery disease
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Objectives To compare patients with coronary artery disease and healthy controls with respect to cognitive function and driving performance.Design and setting A controlled study conducted between April 1999 and January 2001.Subjects Forty-four patients with stable coronary artery disease scheduled for cardiac intervention with coronary artery bypass surgery or percutaneous coronary intervention. Forty volunteers of similar age without symptoms of coronary artery disease served as controls.Main outcome measures On-road driving scores in five specific test areas with a rating scale from 1 to 5. Neuropsychological test scores, including 12 tests.Results Compared with controls, patients with coronary artery disease had lower scores in all areas of the on-road driving test (p<0.05) and in the neuropsychological tests assessing psychomotor speed, visual and verbal memory, focused attention and simultaneous capacity (p<0.05). The difference between the groups in the on-road driving test appeared to be more pronounced among those above 65 years-of-age. Both patients and controls rated their performance significantly higher than the traffic inspector (p<0.05).Conclusions Cognitive function and driving performance may be impaired in patients with coronary artery disease.
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| 8. |
- Ahlgren, Ewa, 1959-, et al.
(författare)
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Neurocognitive impairment and driving performance after coronary artery bypass surgery
- 2003
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Ingår i: European Journal of Cardio-Thoracic Surgery. - : Oxford University Press (OUP). - 1010-7940 .- 1873-734X. ; 23:3, s. 334-340
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Neurocognitive impairment is common after cardiac surgery but few studies have examined the relationship between postoperative neuropsychological test performance and everyday behavior. The influence of postoperative cognitive impairment on car driving has previously not been investigated. The purpose of this study was to evaluate neurocognitive function and driving performance after coronary artery bypass grafting (CABG).Methods: Twenty-seven patients who underwent coronary artery bypass grafting with standard cardiopulmonary bypass technique and 20 patients scheduled for percutaneous coronary intervention (PCI) under local anesthesia (control group) were enrolled in this prospective study conducted from April 1999 to September 2000. Complete data were obtained in 23 and 19 patients, respectively. The patients underwent neuropsychological examination with a test battery including 12 tests, a standardized on-road driving test and a test in an advanced driving simulator before and 4–6 weeks after intervention.Results: More patients in the coronary artery bypass grafting group (n=11, 48%) than in the percutaneous coronary intervention group (n=2, 10%) showed a cognitive decline after intervention (P=0.01). In the on-road driving test, patients who underwent coronary artery bypass grafting deteriorated after surgery in the cognitive demanding parts like traffic behavior (P=0.01) and attention (P=0.04). Patients who underwent percutaneous intervention deteriorated in maneuvering of the vehicle (P=0.04). No deterioration was detected in the simulator in any of the groups after intervention. Patients with a cognitive decline after intervention also tended to drop in the on-road driving scores to a larger extent than did patients without a cognitive decline.Conclusion: This study indicates that cognitive functions important for safe driving may be influenced after cardiac surgery.
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| 9. |
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| 10. |
- Andersson, Klas J., et al.
(författare)
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Preparation, Structure, and Orientation of Pyrite FeS2{100} Surfaces : Anisotropy, Sulfur Monomers, Dimer Vacancies, and a Possible FeS Surface Phase
- 2014
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 118:38, s. 21896-21903
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Tidskriftsartikel (refereegranskat)abstract
- Sulfur dimer (S-2(2-)) terminated pyrite FeS2{100} surfaces with a low energy electron diffraction (LEED) pattern of 2 x 1 symmetry are reported. The 2 X 1 symmetry correlates with the orientation of the anisotropic surface structure and external symmetry of macroscopic striations on the pyrite cube face. The basic condition to form these surfaces is a mild 200 V Ne+ sputter-cleaning procedure followed by a 570 K anneal of the sample in a 10(-7) Ton S-2(g) atmosphere. Controlled amounts of surface sulfur monomers (S2-) can be introduced by mild sputtering of the sulfur dimer terminated surfaces. At low monomer concentrations the surface displays the same characteristic 1 x 1 LEED pattern as that for fracture-generated surfaces. With increasing sulfur depletion, a (1/ root 2 x 1/ root 2)R45 degrees LEED pattern emerges, and soft X-ray photoelectron spectroscopy (XPS) results show a sulfur dinner deficient near-surface region and a new high binding energy sulfur spectral component suggesting the presence of local coordination environments where sulfur monomers are coordinated by four Fe ions compared to three as in the pyrite structure. The plausible formation of a defective FeS-like surface phase where monomeric sulfurs are coordinated by four Fe ions, and bond counting energetics favoring surface sulfur monomer recombination around Fe vacancy sites on pyrite FeS2{100}, both imply surface sulfur dimer vacancy sites with unique adsorption and reactivity properties. Taken together, our results suggest a very rich and dynamic defect structural landscape at pyrite FeS2{100} surfaces with direct implications for its surface chemical activity.
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| 11. |
- Arneson, Hanna, et al.
(författare)
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Psychiological empowerment at the workplace and self-rated health and burnout : a 2-yeah longitudinal analysis in a sample of Swedish employees
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- PURPOSE: To explore the gender-specific longitudinal association between psychological empowerment at the workplace and self-rated health and burnout in a working population.MATERIAL AND METHOD: The participants were employees working in the public service sector in central Sweden. The baseline survey was carried out in 2001 and the follow-up in 2003. The questionnaire was answered by 715 respondents at both points in time (overall response rate 67%). Measures used were Psychological Empowerment Instrument by Spreitzer, the SF-36, the EQ-5D, and the Copenhagen Burnout Inventory. Gender specific differences in average score for self-rated health and burnout at follow-up were assessed using multiple linear regression adjusted for age, education, study cohort and self-rated health and burnout at baseline. An analysis on interactional effects due to gender was also performed.RESULTS: For women, increasing levels of psychological empowerment at work at baseline are associated with less bodily pain, better physical role function and mental health in the multivariate analysis at follow-up two years later. For men, increased psychological empowerment at baseline is significantly associated with better self-rated health as measured by the EQ-5D VAS at follow-up in the multivariatc analysis. Higher levels of psychological empowerment at baseline show a statistically significant association with a lower degree of burnout at follow-up in the univariate analysis for men and women. However, the associations diminished after adjustments in the multivariate analyses. No significant gender x empowerment interaction appeared.CONCLUSION: Psychological empowerment in working life was associated with somatic and mental aspects of SRH two years later for women. Men seem to be less affected by psychological empowerment, yet an association with the EQ-5D V AS appeared. Psychological empowerment did not predict burnout two years later for either men or women.
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| 12. |
- Arneson, Hanna, et al.
(författare)
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Psychological empowerment and self-rated health and burnout in a sample of Swedish employees
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- PURPOSE: To explore the gender-specific association between psychological empowerment and self-rated health and burnout in a working population.MATERIAL AND METHOD: A cross-sectional survey was carried out among 1,243 employees (response rate 81% (n=1007), 65 % females). Psychological empowerment was measured by the Spreitzer questionnaire, developed for a working life context. The questionnaire includes the subscales: meaning, competence, self-determination and impact. Self-rated health was evaluated with EQ-5D and SF-36 and the Copenhagen Burnout Inventory was used to measure burnout.RESULTS: Men reported a greater degree of empowerment than women in terms of self-determination and impact. Significant associations (p<0.05) were found between psychological empowerment and self-rated health and burnout. Men and women with higher levels of empowerment reported significantly better health compared to those with lower levels of empowerment. In multivitriate analyses, all four subscales of empowerment were associated with burnout among both men and women. The most pronounced association with self-rated health was seen for the subscale impact. These associations were particularly strong among women.CONCLUSION: Psychological empowerment in working life is associated with self-rated health and burnout. Interventions aiming to promote health at work or aiming to prevent burnout may therefore benefit if they comprise empowerment in terms of impact, self-determination, meaning and competence. Also, workplace health promotion that includes empowerment processes should be gender conscious.
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| 13. |
- Arneson, Hanna, et al.
(författare)
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Psychological empowerment, social support at the workplace and self-rated health and burnout : a 2-year longitudinal analysis in a sample of Swedish employees
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- PURPOSE: To explore the gender-specific longitudinal association between a combination of psychological empowerment and social support at the workplace and self-rated health and burnout in a working population.MATERIAL AND METHOD: The participants were employees working in the public service sector in central Sweden. The baseline survey in two cohorts was carried out in 2001 and the follow-up in 2003. The questionnaire was answered by 715 respondents at both points in time (overall response rate 67%). Measures used were the Psychological Empowerment Instrument by Spreitzer, the social support dimension in the Demand-Control-Support Questionnaire, the SF-36, the EQ-5D, and the Copenhagen Burnout Inventory. Based on empirical medians, psychological empowerment and social support at baseline were combined into four categories. Mlltivariate comparisons adjusted for age, education, study cohort and SRH and burnout at baseline were performed using multiple linear regression analysis. The genderxempowerment and social support interaction effect was assessed in the multiple linear regression analysis. All analyses were performed for men and women separately.RESULTS: For women, a combination of high psychological empowerment and high social support at the workplace, in comparison with a combination of low psychological empowerment and low social support, is strongly associated with better SRH (bodily pain, general health, vitality, social functioning, emotional role, mental health, the EQ-5D VAS, and EQ-5D index) and lower levels of work-related burnout at the 2-year follow-up after adjusting for demographics and baseline SRH and burnout. For men, there are univariate associations with burnout and some associations with SRH. After adjustments for demographics and baseline SRH and burnout, psychological empowerment and social support is associated with SRH as measured by the EQ-5D VAS for men. The gender x empowerment and social support interaction analyses confirm gender differences regarding bodily pain, social function, and work-related burnout.CONCLUSION: A combination of psychological empowerment and social support in working life strongly affects SRH and work-related burnout two years later for women, but only in part for men.
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| 14. |
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| 15. |
- Berg, Anne Ingeborg, 1973, et al.
(författare)
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Living with stable MCI: Experiences among 17 individuals evaluated at a memory clinic.
- 2013
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Ingår i: Aging & mental health. - : Informa UK Limited. - 1364-6915 .- 1360-7863. ; 17:3, s. 293-9
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Mild cognitive impairment (MCI) is a state of mildly impaired cognitive functioning but with an intact capability of performing basic daily activities. Few studies have targeted personal narratives from persons living with MCI, the major focus in this study is directed to methods for better predictions of the likelihood for conversion to dementia. This study directly explores experiences among individuals who have lived with MCI over seven years without converting to dementia. Methods: Seventeen individuals, who had been diagnosed with MCI across four occasions over a seven-year period at a memory clinic, were interviewed at a single occasion about their experiences of living with MCI, life events, stress, coping, psychosocial resources, and lifestyle behaviors. Results: Thematic analysis of the transcripts of the interviews resulted in themes revolving around the life situation and events related to the first visit at the memory clinic, coping with lower cognitive capacity with the aim of enhancing quality of life, and worries about dementia and further cognitive deteriorations. Conclusion: The participants' experiences of living with MCI indicate that issues and changes in life situations such as long-term stress, retirement, loss of relatives, perceived heritability of dementia, needs to be understood in the context of the individual's understanding and interpretation of their everyday cognitive functioning. Also, supportive long-term contacts with the specialist care unit were vital for creating a personal understanding of MCI. Addressing the intra-personal dynamics of cognitive functioning in the boundary between normal and pathological cognitive aging can also improve diagnostic accuracy.
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| 16. |
- Bergman, Anders, et al.
(författare)
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Characterisationat low voltage of two reference lightning impulse dividers
- 2017
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Konferensbidrag (refereegranskat)abstract
- An effort is pursued by several European National Measurement Institutes to lower the uncertainties in calibration of UHV measuring systems for lighting impulse. To this end, several reference dividers are investigated as regards their accuracy both for amplitude and for time parameters. At SP - RISE Research Institutes of Sweden, a 500 kV resistive reference divider has been in use since 2000. Additionally an 800 kV resistive divider is investigated as a possible reference divider for UHV lightning impulse measuring systems. The best uncertainty for the 500 kV reference measuring system is 1 % for voltage amplitude and 3 % for time parameters. The present work aims at lowering these uncertainties by means of better characterisation and evaluation of the possibilities to apply corrections for known errors. The scale factor and dynamic behaviour of a resistive divider can be conveniently determined at low voltage and frequency. Further experiments such as linearity tests and augmented by scientific work is needed to ascertain the performance at high voltage. Step response plays a major role in the characterisation of dividers, and in this work much effort has gone into gathering step responses and evaluating them for various circuit layouts to characterise the variation of the step response due to circuit dimensions and diverse proximity effects. The step applied to the divider is generated by a mercury wetted relay based step generator with an output voltage of 200 V. The step rise-time is a few ns, and thus appreciably faster than the response of the divider. Apart from inspection of the step response itself, evaluation of measurement errors is performed by convolving an ideal curve with the step response of the divider, including its transmission cable. The convolved signal is evaluated with impulse evaluation software and the parameters compared to the ideal input. The difference is a measure of the errors introduced by the divider. This procedure follows IEC 60060-2: 2010.
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| 17. |
- Bergman, Anders, et al.
(författare)
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Characterization of a fast step generator
- 2017
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Konferensbidrag (refereegranskat)abstract
- Lighting impulse measurements are made as a matter of routine in high voltage testing of high-voltage electrical equipment. The test is often decisive for acceptance of the equipment under test, and consequently proper and precise calibration of the measuring system is needed. The present work centres on the need to quantify the errors of reference measuring systems for lightning impulse. Scale factor determination at low frequency (or DC) is the starting point for this determination. The extrapolation from this frequency domain to the domain where microsecond pulses must be faithfully captured requires application either of methods in the frequency domain or in the time domain. Radio frequency measurements are only well defined for coaxial structures and at impedances in the range of 50 O or thereabouts, making them difficult to apply to the large structures of high-voltage measuring systems. The converse method in the time domain is to apply a Dirac impulse to the system and calculate the response to an assumed input signal by convolution. A true Dirac pulse is not readily available and in practice the applied pulse is a step voltage, which is then derived with respect to time and convolved with the applied signal to obtain the response of the measuring system. The step generator used for this purpose should have very fast front without oscillations. The intent is to achieve a close approximation of an ideal step function, which when derived with respect to time, yields the impulse response of a tested system. A necessary prerequisite is that the step is much steeper than the lightning impulse, and is flat after the step on times much longer than the impulse. The ideal switch element in such a step generator should have infinite resistance and zero capacitance in the off-state, very fast switching to on-state and very low resistance in on-state. The mercury wetted reed switch has often been used for this purpose since it has good characteristics in all these respects. Few, if any, electronic components exhibit competitive advantages compared to the reed switch. The relative lack of parasitic effects means that it is close to being an ideal device. Based on earlier experiences by the authors, a new design has been developed with focus on electrical screening and coaxial design in order to realise a step generator that works into a high impedance instrument. Considerable work has been performed to characterise the new device with regard to steepness of step and most importantly, to voltage stability after the step. The most demanding part of this work has been to separate the performance of the switch from that of the oscilloscope. Findings indicate that the step rise-time is less than 0.5 ns, and settling to within 0.5 % within 10 ns.
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| 18. |
- Bergman, Anders, et al.
(författare)
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Influence of coaxial cable on response of high-voltage resisitive dividers
- 2017
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Konferensbidrag (refereegranskat)abstract
- An effort is pursued by several European National Measurement Institutes to lower the uncertainties in calibration of UHV measuring systems for lightning impulse. To this end, several reference dividers are investigated as regards their accuracy both for amplitude and for time parameters. During these investigations a deterioration of step response was identified when longer coaxial cables were inserted in the measuring circuit. The measured front time T1 was also affected, in one observed case by 2.5 % elongation of front time as another 25 m cable was inserted. Compared to the intention to calibrate front time measurement to better than 5 % uncertainty for front time, this contribution must be well known, or preferably be eliminated. This paper presents the experimental findings from these investigations. The investigated cables included selected coaxial, tri-axial, and cables with a corrugated screen. The effect of cable length was also studied. The influence was first discovered when applying a very fast step (rise-time < 4 ns) to the high voltage arm of a resistive divider and convolution of this step with the time derivative of an ideal lightning impulse with 0.84/60 µs impulse. The calculated output was analysed with IEC 61083 compliant software to evaluate the front time. Subsequently, these analyses have been augmented by additional comparative measurements where two reference dividers were connected to the same impulse generator, and varying the cable length of one of them. The summarized changes in front time calculated for different combinations of cable and impulse voltage dividers are shown and discussed. It is noted that a change in T1 error depends both on length of cable and its type. The results show that non-negligible front time errors may be introduced when the cable length is increased. To support these findings, further tests have been carried out with two reference impulse dividers connected in standard calibration configuration in accordance with IEC 60060-2. One divider was used as reference, while the cable for the other was varied. In this way, the change of error between configurations could be measured. A theoretical study has also been performed, calculating the distortion of a lightning impulse on a coaxial cable. The results agree qualitatively with experiments, but the detailed results show discrepancies that need further investigation.
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| 19. |
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| 20. |
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| 21. |
- Bernitt Cartemo, Petty, 1984, et al.
(författare)
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Building a generic voxel phantom ofIRINA for Monte Carlo simulations
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The human phantom IRINA, which is widely used for whole body counting calibrations, has been modelled using MATLAB. This document summa-rizes and explains the procedure that was applied for building voxel ver-sions of IRINA in standing position. All 6 sizes in standing positions were successfully modelled with the help of MATLAB and the files are ready to use for any MC simulation. The MC code GATE was used to verify the geometry of the IRINA phantom by comparing the placement of source tubes and scatterers in the Monte Carlo model to the original IRINA docu-mentation. The methodology can easily be used for building voxel phan-toms of IRINA in sitting and bending position, as well as any other geome-try that may be needed.
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| 22. |
- Bernitt Cartemo, Petty, 1984, et al.
(författare)
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Comparison of computational phantoms and investigation of the effect of biodistribution on activity estimations
- 2016
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 171:3, s. 358-364
-
Tidskriftsartikel (refereegranskat)abstract
- We have made a comparison between two computational phantoms, modeled from the unified phantom UPh-08T, for whole-body counting applications. One of these was further compared with the ICRP reference adult male computational phantom. The simulations that were performed for the comparison of all three voxel phantoms use various distributions of 60Co. The two voxel phantoms of the UPh-08T showed good agreement, despite different methods of phantom modeling. Also, effects on efficiency of the inhomogeneous distribution of a radionuclide in the computational UPh-08T phantom were studied, using the realistic biodistribution of 140La. Our results show that the activity estimation of radionuclides, which are inhomogeneously distributed in the human body, will be in error if a homogeneous distribution is assumed for the calibration of whole-body counting systems.
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| 23. |
- Bernitt Cartemo, Petty, 1984, et al.
(författare)
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Depth Profiling with the Chalmers Pulsed Positron Beam
- 2014
-
Ingår i: International Journal of Nuclear Energy Science and Technology. - 1741-637X .- 1741-6361. ; 8:2, s. 105 - 116
-
Tidskriftsartikel (refereegranskat)abstract
- Positron lifetime measurements are used as a tool for obtaining a deeper understanding of positron behaviour in solids and calibrating the Chalmers Pulsed Positron Beam. Experiments are executed for positron energies up to 13 keV corresponding to the maximum penetration depth in Au of roughly 400 nm and measurement results are compared to PENELOPE simulations. Reference towards Makhov modelling is made. The future goal of the study is to investigate the depth dependence of ion-induced radiation damage where positrons will be used to characterise sizes and intensities of vacancy-type lattice defects.
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| 24. |
- Bernitt Cartemo, Petty, 1984, et al.
(författare)
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Sensitivity of the neutronic design of an Accelerator-Driven System (ADS) to the anisotropy of yield of the neutron generator and variation of nuclear data libraries
- 2013
-
Ingår i: Proceeding of ESARDA meeting 2013.
-
Konferensbidrag (refereegranskat)abstract
- The Accelerator-Driven System concept was chosen to be a basis for the Multi-purpose Hybrid Research Reactor for High-tech Applications (MYRRHA), which can operate in both sub-critical and critical mode. Therefore, the design studies in the scope of this project were varying from accelerator and material aspects to the demonstration of transmutation possibilities of the system. However, the sensitivity of neutron characteristics of the system to the anisotropy of yield of neutron generator and variation of nuclear data libraries may appear to be an important issue.In this study the corresponding sensitivity analysis was performed in order to evaluate the sensitivity of ADS neutronic design to the variation of nuclear data libraries and influence of the anisotropy of the neutron yield of the accelerator.
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| 25. |
- Beye, Martin, et al.
(författare)
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Chemical Bond Activation Observed with an X-ray Laser
- 2016
-
Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 7:18, s. 3647-3651
-
Tidskriftsartikel (refereegranskat)abstract
- The concept of bonding and antibonding orbitals is fundamental in chemistry. The population of those orbitals and the energetic difference between the two reflect the strength of the bonding interaction. Weakening the bond is expected to reduce this energetic splitting, but the transient character of bond-activation has so far prohibited direct experimental access. Here we apply time-resolved soft X-ray spectroscopy at a free electron laser to directly observe the decreased bonding antibonding splitting following bond-activation using an ultrashort optical laser pulse.
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| 26. |
- Beye, M., et al.
(författare)
-
Selective Ultrafast Probing of Transient Hot Chemisorbed and Precursor States of CO on Ru(0001)
- 2013
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 110:18
-
Tidskriftsartikel (refereegranskat)abstract
- We have studied the femtosecond dynamics following optical laser excitation of CO adsorbed on a Ru surface by monitoring changes in the occupied and unoccupied electronic structure using ultrafast soft x-ray absorption and emission. We recently reported [M. Dell'Angela et al. Science 339, 1302 (2013)] a phonon-mediated transition into a weakly adsorbed precursor state occurring on a time scale of >2 ps prior to desorption. Here we focus on processes within the first picosecond after laser excitation and show that the metal-adsorbate coordination is initially increased due to hot-electron-driven vibrational excitations. This process is faster than, but occurs in parallel with, the transition into the precursor state. With resonant x-ray emission spectroscopy, we probe each of these states selectively and determine the respective transient populations depending on optical laser fluence. Ab initio molecular dynamics simulations of CO adsorbed on Ru(0001) were performed at 1500 and 3000 K providing insight into the desorption process.
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| 27. |
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| 28. |
- Bjerg, Anders, et al.
(författare)
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Shorter time to clinical decision in work-related asthma using a digital tool
- 2020
-
Ingår i: ERJ open research. - Lausanne, Switzerland : European Respiratory Society (ERS). - 2312-0541. ; 6:3
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- PEF curves are a useful but cumbersome tool in diagnosing work-related asthma. Using a digital spirometer and smartphone app, time to clinical decision could be shortened by 6-7 weeks. Physician's time spent analysing PEF data is also shortened.
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| 29. |
- Bjerke, Maria, 1977, et al.
(författare)
-
Cerebrovascular Biomarker Profile Is Related to White Matter Disease and Ventricular Dilation in a LADIS Substudy.
- 2014
-
Ingår i: Dementia and geriatric cognitive disorders extra. - : S. Karger AG. - 1664-5464. ; 4:3, s. 385-94
-
Tidskriftsartikel (refereegranskat)abstract
- Small vessel disease (SVD) represents a common often progressive condition in elderly people contributing to cognitive disability. The relationship between cerebrospinal fluid (CSF) biomarkers and imaging correlates of SVD was investigated, and the findings were hypothesized to be associated with a neuropsychological profile of SVD.
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| 30. |
- Bjerke, Maria, 1977, et al.
(författare)
-
Subcortical vascular dementia biomarker pattern in mild cognitive impairment.
- 2009
-
Ingår i: Dementia and geriatric cognitive disorders. - : S. Karger AG. - 1421-9824 .- 1420-8008. ; 28:4, s. 348-56
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Mild cognitive impairment (MCI) is an etiologically unclear disorder. Cerebrospinal fluid (CSF) biomarkers are potentially useful for the differentiation between various MCI etiologies. AIM: The aim of the study was to assess whether baseline CSF hyperphosphorylated tau (P-tau), total tau (T-tau), amyloid beta 1-42 (Abeta(42)) and neurofilament light (NF-L) in patients with MCI could predict subcortical vascular dementia (SVD) and Alzheimer's disease (AD) at follow-up. METHODS: Biomarker levels were assessed by Luminex xMAP technology and ELISA. RESULTS: Increased baseline concentrations of NF-L significantly separated MCI-SVD from stable MCI. The MCI-SVD patients were inseparable from stable MCI but separable from patients developing AD (MCI-AD) on the basis of Abeta(42,) T-tau and P-tau(181) levels. CONCLUSION: A combination of the biomarkers Abeta(42), T-tau, P-tau(181) and NF-L has the potential to improve the clinical separation of MCI-SVD patients from stable MCI and MCI-AD patients.
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| 31. |
- Bombarda, F., et al.
(författare)
-
Runaway electron beam control
- 2019
-
Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 61:1
-
Tidskriftsartikel (refereegranskat)
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| 32. |
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| 33. |
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| 34. |
- Bos, Isabelle, et al.
(författare)
-
The frequency and influence of dementia risk factors in prodromal Alzheimer's disease
- 2017
-
Ingår i: Neurobiology of Aging. - : Elsevier. - 0197-4580 .- 1558-1497. ; 56, s. 33-40
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated whether dementia risk factors were associated with prodromal Alzheimer's disease (AD) according to the International Working Group-2 and National Institute of Aging-Alzheimer's Association criteria, and with cognitive decline. A total of 1394 subjects with mild cognitive impairment from 14 different studies were classified according to these research criteria, based on cognitive performance and biomarkers. We compared the frequency of 10 risk factors between the subgroups, and used Cox-regression to examine the effect of risk factors on cognitive decline. Depression, obesity, and hypercholesterolemia occurred more often in individuals with low-AD-likelihood, compared with those with a high-AD-likelihood. Only alcohol use increased the risk of cognitive decline, regardless of AD pathology. These results suggest that traditional risk factors for AD are not associated with prodromal AD or with progression to dementia, among subjects with mild cognitive impairment. Future studies should validate these findings and determine whether risk factors might be of influence at an earlier stage (i.e., preclinical) of AD.
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| 35. |
- Cartemo, Petty, et al.
(författare)
-
Letter to the Editor.
- 2016
-
Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 168:2
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 36. |
- Chen, Chen, et al.
(författare)
-
Solvation structures of protons and hydroxide ions in water
- 2013
-
Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 138:15, s. 154506-
-
Tidskriftsartikel (refereegranskat)abstract
- X-ray Raman spectroscopy (XRS) combined with small-angle x-ray scattering (SAXS) were used to study aqueous solutions of HCl and NaOH. Hydrated structures of H+ and OH- are not simple mirror images of each other. While both ions have been shown to strengthen local hydrogen bonds in the hydration shell as indicated by XRS, SAXS suggests that H+ and OH- have qualitatively different long-range effects. The SAXS structure factor of HCl (aq) closely resembles that of pure water, while NaOH (aq) behaves similar to NaF (aq). We propose that protons only locally enhance hydrogen bonds while hydroxide ions induce tetrahedrality in the overall hydrogen bond network of water.
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| 37. |
- Chernikova, Dina, 1982, et al.
(författare)
-
A direct method for evaluating the concentration of boric acid in a fuel pool using scintillation detectors for joint-multiplicity measurements
- 2013
-
Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 714, s. 90-97
-
Tidskriftsartikel (refereegranskat)abstract
- The present investigations are aimed at the development of a direct passive non-intrusive method for determining the concentration of boric acid in a spent fuel pool using scintillation detectors with the purpose of correcting joint-multiplicity measurement results. The method utilizes a modified relation between two gamma lines with energy of 480 keV and 2.23 MeV, respectively. The gamma line at 480 keV belongs to the thermal neutron capture in boron. The 2.23 MeV gamma line characterizes the capture of thermal neutrons in hydrogen. Thus, the relation between them can reveal the concentration of the boron in the fuel pool. In order to test this method, first MCNPX and MCNP-PoliMi simulations were performed. Then, based on the results of Monte Carlo simulations, the method was verified by an experimental study with a 241Am-Be source and EJ-309 scintillation detectors. The concentration of boron in water varied from 1550 ppm to 4000 ppm. The results of these tests are provided in the paper and they show that the spectral ratio between these two lines can in principle be used to determine the boron content.
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| 38. |
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| 39. |
- Chernikova, Dina, 1982, et al.
(författare)
-
A potential alternative/complement to the traditional thermal neutron based counting in Nuclear Safeguards and Security
- 2016
-
Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 810, s. 164-171
-
Tidskriftsartikel (refereegranskat)abstract
- A new concept for thermal neutron based correlation and multiplicity measurements is proposed in this paper. The main idea of the concept consists of using 2.223 MeV gammas (or 1.201 MeV, DE) originating in the (1) H (n,gamma)D-2-reaction instead of using traditional thermal neutron counting. Results of investigations presented in this paper indicate that gammas from thermal neutron capture reactions preserve the information about the correlation characteristics of thermal (fast) neutrons in the same time scale. Therefore, instead of thermal neutron detectors (or as a complement) one may use traditional and inexpensive gamma detectors, such as Nal, BGO, CdZnTe or any other gamma detector. In this work we used D8 x 8 cm(2) Nal scintillator to test the concept. Thus, the new approach helps to address the problem of replacement of He-3-counters and problems related to the specific measurements of spent nuclear fuel directly in the spent fuel pool. It has a particular importance for Nuclear Safeguards and Security. Overall, this work represents the proof of concept study and reports on the experimental and numerical evidence that thermal neutron capture gammas may be used in the context of correlation and multiplicity measurements. Investigations were performed using a (252)-Cf-correlated neutron source and an Am-241-Be-random neutron source. The related idea of the Gamma Differential Die-Away approach is investigated numerically in this paper as well, and will be tested experimentally in future work.
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| 40. |
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| 41. |
- Chernikova, Dina, 1982, et al.
(författare)
-
Novel passive and active tungsten-based identifiers for maintaining the continuity of knowledge of spent nuclear fuel copper canisters
- 2015
-
Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 75, s. 219-227
-
Tidskriftsartikel (refereegranskat)abstract
- A new approach to provide a long-term safeguards identification of spent nuclear fuel containers, in particular copper canisters, is presented in this paper. The approach proposes the use of a tungsten insert marked with a binary code and placed inside the container. The insert is read with a combination of two independent techniques, radiation and ultrasonic measurements, in order to get a unique identification of the cask. Passive and active versions of the tag are considered. The passive version makes use of the radiation coming from the spent nuclear fuel itself. The active version of the tag is based on the use of an artificially introduced mixture of α-emitting isotopes, such as 241Am with materials, 11B and 23Na, which easily undergo α-induced reactions with emission of specific γ-lines, 2313 keV and 1809 keV, respectively. The paper discusses results of the radiation and ultrasonic measurements and Monte-Carlo evaluations as the first proof of the concept. The results of the investigations show the strong potential for this concept to maintain the continuity of knowledge of spent nuclear fuel copper canisters for a time scale up to a few thousands years without compromising the environmental safety of the casks.
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| 42. |
- Chernikova, Dina, 1982, et al.
(författare)
-
Testing a direct method for evaluating the concentration of boron in a fuel pool using scintillation detectors, and a 252Cf and an 241Am-Be source
- 2013
-
Ingår i: Proceeding of ESARDA meeting 2013.
-
Konferensbidrag (refereegranskat)abstract
- The present investigations are aimed at the development and testing of a direct non-destructive method for evaluating the concentration of boron in a fuel pool using scintillation detectors. The method uses a modified ratio between two gamma lines with energy of 480 keV and 2.23 MeV. These lines belong to the capture of a thermal neutron in boron and hydrogen, respectively. The relation between them can reveal the concentration of boron in the fuel pond.The method proposed was tested in a laboratory experiment with a 252Cf and an 241Am-Be source. EJ-309 liquid scintillation detectors were used for measurements of gamma spectra. The concentration of boron in water varied from 1550 ppm to 4200 ppm. The optimization and test studies were performed via MCNPX simulations.The results of these tests are provided in the present paper and they show that the boron content in water can be determined through using the characteristics of gamma lines with energy of 480 keV and 2.23 MeV.
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| 43. |
- Chernikova, Dina, 1982, et al.
(författare)
-
Testing of small detectors with glass rod light guides for multiplicity measurement purposes
- 2012
-
Ingår i: Proceedings of The 53nd Annual Meeting of the Institute of Nuclear Materials Management.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we investigate the applicability of small scintillators with glass rod lightguides to measure both neutrons and gamma rays from the sample. Experimental test ofthese detectors and their suitability for the task can be performed at Lund University usingnatural uranium rods, therefore the MCNPX simulation set-up corresponds to the Lund con-figuration. The long-term goal of this research is to develop a method of joint-multiplicitycounting for fuel evaluation into a technology capable of quantifying plutonium in the fuelpool, where a lot of factors, such as presence of neutron absorbers (boron acid), can affect al-most all parameters, such as multiplication etc. Therefore, part of the present investigationswas devoted to the development of a direct method for determination of the concentrationof boron acid in the fuel pool using scintillation detectors with further correction of mea-surement results. For this purpose we suggest a method which utilizes a relation betweengamma lines with energy of 480 keV and 2.23 MeV for the direct evaluation of concentrationof boron acid in water. Test results of the new method, and an answer to questions regardingthe ability to measure both neutron and gamma rays using small scintillation detectors withglass rod light guides are provided in this paper.
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| 44. |
- Chernikova, Dina, 1982, et al.
(författare)
-
The neutron-gamma Feynman variance to mean approach: Gamma detection and total neutron-gamma detection (theory and practice)
- 2015
-
Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 782, s. 47-55
-
Tidskriftsartikel (refereegranskat)abstract
- Two versions of the neutron gamma variance to mean (Feynman-alpha method or Feynman-Y function) formula for either gamma detection only or total neutron gamma detection, respectively, are derived and compared in this paper. The new formulas have particular importance for detectors of either gamma photons or deleclors sensitive to both neutron and gamma radialion. If applied to a plastic or liquid deleclor, he total neutron-gamma detection Feynman-Y expression corresponds Lo a situation where no discrimination is made between neutrons and gamma parlicles. The gamma variance Lo mean formulas are useful when a detector of only gamma radialion is used or when working with a combined neutron-gamma deleclor at high count rates. The theoretical derivation is based on the Chapman-Kolmogorov equation with the inclusion of general reactions and corresponding intensities for neutrons and gammas, but with the inclusion of prompt reactions only. A one energy group approximation is considered. The comparison of the two different theories is made by using reaction intensities obtained in MCNPX simulations with a simplified geometry for two scintillation detectors and a Cf-252-source. In addition, the variance to mean ratios, neutron, gamma and total neutron-gamma are evaluated experimentally for a weak Cf-252 neutron-gamma source, a Cs-137 random gamma source and a Na-22 correlated gamma source. Due to the focus being on the possibility of using neutron-gamma variance to mean theories for both reactor and safeguards applications, we limited the present study to the general analytical expressions for Feynman-alpha formulas.
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| 45. |
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| 46. |
- Cucchiara, BL, et al.
(författare)
-
Early impairment in consciousness predicts mortality after hemispheric ischemic stroke
- 2004
-
Ingår i: Critical Care Medicine. - 0090-3493 .- 1530-0293. ; 32:1, s. 241-245
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Early predictors of poor outcome after acute ischemic stroke may be useful in selecting patients for potentially beneficial but high-risk interventions. Design. Cohort study of patients given placebo in a randomized clinical trial. Setting. Multicenter trial at 139 U.S. and 14 Canadian hospitals. Patients. A cohort of 564 placebo-treated patients with major anterior circulation ischemic stroke enrolled in the Clomethiazole in Acute Stroke Study-Ischemic Stroke (CLASS-I) trial. Patients did not have significant impairment in consciousness at baseline and were enrolled within 12 hrs of symptom onset. Interventions: Prospective data collection of a number of clinical variables including use of a 6-point level of consciousness scale (1 = awake, 6 = no reaction to pain) to measure patients' level of consciousness at enrollment and 12 additional times during the first 24 hrs after enrollment. The ability of level of consciousness score and additional clinical data to predict 30-day mortality was assessed. Measurements and Main Results., At 1 month, 114 of 564 patients (20%) had died. In univariate analysis, factors significantly associated with mortality included older age, white race, higher National Institutes of Health Stroke Scale score, higher serum glucose, atrial fibrillation, and any impairment in level of consciousness (p < .05). After controlling for these factors, increasing level of consciousness score at 3 hrs after enrollment and at all but one subsequent time point was significantly associated with increased mortality (odds ratio, 1.8 per point, 95% confidence interval, 1.2-2.6, p = .003 at 3-hr time point). Maximum level of consciousness score during the initial 24 hrs of monitoring also predicted mortality (odds ratio, 1.9 per point, 95% confidence interval, 1.4-2.5, p < .001). Conclusion: The development of a decreased level of consciousness within the initial hours after stroke onset, as evaluated by a simple six-point scale, is a powerful independent predictor of mortality after major anterior circulation ischemic stroke.
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| 47. |
- Cucchiara, B, et al.
(författare)
-
Lack of hemispheric dominance for consciousness in acute ischaemic stroke
- 2003
-
Ingår i: Journal of Neurology, Neurosurgery and Psychiatry. - : BMJ. - 0022-3050 .- 1468-330X. ; 74:7, s. 889-892
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Previous reports have suggested left hemispheric dominance for maintaining consciousness, although there is controversy over this claim. Objective: To compare early impairment of level of consciousness between patients with right and left hemispheric stroke. Methods: Data from 564 patients with ischaemic stroke enrolled in the placebo arm of a trial of a putative neuroprotectant were analysed. All patients had major hemispheric stroke with cortical dysfunction, visual field deficit, and limb weakness, with symptom onset within 12 hours of enrolment. Patients were prospectively evaluated on a predefined scale (1-6, 1 = fully awake, higher scores representing greater impairment) to measure level of consciousness at multiple time points over the initial 24 hours after presentation. The National Institutes of Health (NIH) stroke scale score at presentation and infarct volume at 30 days were determined. Results: Some degree of impairment in level of consciousness was observed in 409 of the 564 patients (73%). Median maximum sedation score was 2 for both right and left hemispheric stroke (p = 0.91). Mean sedation score over 24 hours was 1.5 for both right and left stroke (p = 0.75). There was no difference between level of consciousness scores in right and left stroke at any individual time point during the 24 hour monitoring period. No association between side and impairment in level of consciousness was seen after adjustment for stroke severity and infarct volume. Conclusions: In contrast to previous reports, there was no evidence for hemispheric dominance for consciousness in the setting of a major hemispheric stroke.
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| 48. |
- Dahlbom, Anders, et al.
(författare)
-
Detection of Hostile Aircraft Behaviors using Dynamic Bayesian Networks
- 2013
-
Ingår i: Proceedings of the 16th International Conference on Information Fusion. - : IEEE Press. - 9786058631113 - 9781479902842 ; , s. 2033-2040
-
Konferensbidrag (refereegranskat)abstract
- Aircraft Combat Survivability in military air operations is concerned with survival of the own aircraft. This entails analysis of information, detection and estimation of threats, and the implementation of actions to counteract detected threats. Beyond visual range weapons can today be fired from one hundred kilometers away, making them difficult to detect and track. One approach for providing early warnings of such threats is to analyze the kinematic behavior of enemy aircraft in order to detect situations that may point to malicious intent. In this paper we investigate the use of dynamic Bayesian networks for detecting hostile aircraft behaviors.
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| 49. |
- Dell'Angela, M., et al.
(författare)
-
Real-Time Observation of Surface Bond Breaking with an X-ray Laser
- 2013
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 339:6125, s. 1302-1305
-
Tidskriftsartikel (refereegranskat)abstract
- We used the Linac Coherent Light Source free-electron x-ray laser to probe the electronic structure of CO molecules as their chemisorption state on Ru(0001) changes upon exciting the substrate by using a femtosecond optical laser pulse. We observed electronic structure changes that are consistent with a weakening of the CO interaction with the substrate but without notable desorption. A large fraction of the molecules (30%) was trapped in a transient precursor state that would precede desorption. We calculated the free energy of the molecule as a function of the desorption reaction coordinate using density functional theory, including van der Waals interactions. Two distinct adsorption wells-chemisorbed and precursor state separated by an entropy barrier-explain the anomalously high prefactors often observed in desorption of molecules from metals.
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| 50. |
- Dell'Angela, M., et al.
(författare)
-
Vacuum space charge effects in sub-picosecond soft X-ray photoemission on a molecular adsorbate layer
- 2015
-
Ingår i: Structural Dynamics. - : AIP Publishing. - 2329-7778. ; 2:2
-
Tidskriftsartikel (refereegranskat)abstract
- Vacuum space charge induced kinetic energy shifts of O 1s and Ru 3d core levels in femtosecond soft X-ray photoemission spectra (PES) have been studied at a free electron laser (FEL) for an oxygen layer on Ru(0001). We fully reproduced the measurements by simulating the in-vacuum expansion of the photoelectrons and demonstrate the space charge contribution of the high-order harmonics in the FEL beam. Employing the same analysis for 400 nm pump-X-ray probe PES, we can disentangle the delay dependent Ru 3d energy shifts into effects induced by space charge and by lattice heating from the femtosecond pump pulse.
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