| 1. |
- Berlowski, M., et al.
(författare)
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Measurement of eta meson decays into lepton-antilepton pairs
- 2008
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Ingår i: Physical Review D. Particles and fields. - : American Physical Society. - 0556-2821 .- 1089-4918. ; 77:3, s. 032004-
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Tidskriftsartikel (refereegranskat)abstract
- A search for rare lepton decays of the eta meson was performed using the WASA detector at CELSIUS. Two candidates for double Dalitz decay eta -> e(+)e(-)e(+)e(-) events are reported with a background of 1.3 +/- 0.2 events. This allows to set an upper limit to the branching ratio of 9.7x10(-5) (90% CL). The branching ratio for the decay eta -> e(+)e(-)gamma is determined to (7.8 +/- 0.5(stat)+/- 0.8(syst))x10(-3) in agreement with world average value. An upper limit (90% CL) for the branching ratio for the eta -> e(+)e(-) decay is 2.7x10(-5) and a limit for the sum of the eta ->mu(+)mu(-)mu(+)mu(-) and eta ->pi(+)pi(-)mu(+)mu(-) decays is 3.6x10(-4).
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| 2. |
- Keleta, S, et al.
(författare)
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Exclusive measurement of two-pion production in the dd -> He-4 pi pi reaction
- 2009
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474 .- 1873-1554. ; 825:1-2, s. 71-90
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Tidskriftsartikel (refereegranskat)abstract
- The results from the first kinematically complete measurement of the dd -> He-4 pi pi reaction are reported. The aim was to investigate a long standing puzzle regarding the origin of the peculiar pi pi-invariant mass distributions appearing in double pion production in light ion collisions, the so-called ABC effect. The measurements were performed at the incident deuteron energies of 712 MeV and 1029 MeV. with the WASA detector assembly at CELSIUS in Uppsala, Sweden. We report the observation of a characteristic enhancement at low pi pi-invariant mass at 712 MeV, the lowest energy yet. At the higher energy, in addition to confirming previous experimental observations, Our results reveal a strong angular dependence of the pions in the overall centre of mass system. The results are qualitatively reproduced by a theoretical model, according to which the ABC effect is described as resulting from a kinematical enhancement in the production of the pion pairs from two parallel and independent NN -> d pi sub-processes. (C) 2009 Elsevier B.V. All rights reserved.
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| 3. |
- Bargholtz, Chr., et al.
(författare)
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Measurement of the eta -> pi(+)pi(-)e(+)e(-) decay branching ratio
- 2007
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 644:5-6, s. 299-303
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Tidskriftsartikel (refereegranskat)abstract
- The reaction pd -> He-3 eta at threshold was used to provide a clean source of eta mesons for decay studies with the WASA detector at CELSIUS. The branching ratio of the decay eta -> pi(+)pi(-)e(+)e(-) is measured to be (4.3 +/- 1.3 +/- 0.4) x 10(-4).
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| 4. |
- Horsley, A R, et al.
(författare)
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Lung clearance index is a sensitive, repeatable and practical measure of airways disease in adults with cystic fibrosis.
- 2008
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Ingår i: Thorax. - : BMJ. - 1468-3296 .- 0040-6376. ; 63:2, s. 135-40
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Lung clearance index (LCI) is a sensitive marker of early lung disease in children but has not been assessed in adults. Measurement is hindered by the complexity of the equipment required. The aims of this study were to assess performance of a novel gas analyser (Innocor) and to use it as a clinical tool for the measurement of LCI in cystic fibrosis (CF). METHODS: LCI was measured in 48 healthy adults, 12 healthy school-age children and 33 adults with CF by performing an inert gas washout from 0.2% sulfur hexafluoride (SF6). SF6 signal:noise ratio and 10-90% rise time of Innocor were compared with a mass spectrometer used in similar studies in children. RESULTS: Compared with the mass spectrometer, Innocor had a superior signal:noise ratio but a slower rise time (150 ms vs 60 ms) which may limit its use in very young children. Mean (SD) LCI in healthy adults was significantly different from that in patients with CF: 6.7 (0.4) vs 13.1 (3.8), p<0.001. Ten of the patients with CF had forced expiratory volume in 1 s > or = 80% predicted but only one had a normal LCI. LCI repeats were reproducible in all three groups of subjects (mean intra-visit coefficient of variation ranged from 3.6% to 5.4%). CONCLUSIONS: Innocor can be adapted to measure LCI and affords a simpler alternative to a mass spectrometer. LCI is raised in adults with CF with normal spirometry, and may prove to be a more sensitive marker of the effects of treatment in this group.
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| 5. |
- Gustafsson, Per E, 1981-, et al.
(författare)
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Cortisol levels and psychosocial factors in preadolescent children
- 2006
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Ingår i: Stress and Health. - : Wiley. - 1532-3005 .- 1532-2998. ; 22:1, s. 3-9
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Tidskriftsartikel (refereegranskat)abstract
- Regarding the relationship between psychosocial factors and health, one model of explanation states that psychosocial stress constitutes a principal mediator connecting psychosocial factors to health outcome, affecting the body through psychobiological mechanisms. This relationship has scarcely been studied in children. In the present study the relation between diurnal cortisol secretion and psychosocial factors [socio-economic status (SES), immigrant status and impact of psychiatric symptoms] was investigated in a normal population of 6-12 year old children (n = 273). Salivary cortisol levels were measured in the early morning, late morning and in the evening during three consecutive days. Parents answered demographic questionnaires and teachers answered psychiatric questionnaires concerning the children. Children exposed to one or more of the factors of psychosocial load (n = 117) had significantly higher morning (p < 0.001) and evening (p = 0.029) cortisol levels as well as total daily cortisol secretion [measured by the area under the curve (AUC), p = 0.003] compared to the group of children with none of the factors (n = 156). Different psychosocial stressors seemed to influence different parts of the diurnal cortisol curve. In conclusion, this study indicates that even children exposed to a moderate degree of psychosocial load differ in their cortisol levels compared to non-exposed children.
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| 6. |
- Gustafsson, Per E., 1981-, et al.
(författare)
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Diurnal cortisol levels and cortisol response in youths with obsessive-compulsive disorder
- 2008
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Ingår i: Neuropsychobiology. - : S. Karger AG. - 0302-282X .- 1423-0224. ; 57:1-2, s. 14-21
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Tidskriftsartikel (refereegranskat)abstract
- <i>Background/Aims:</i> Recent results indicate a role of the hypothalamic-pituitary-adrenal (HPA) axis in the pathophysiology of obsessive-compulsive disorder (OCD). Although childhood onset is common, the HPA axis has scarcely been studied in young OCD subjects. Therefore, the present study aimed at examining basal and response levels of salivary cortisol in a sample of young OCD subjects. <i>Methods:</i> Twenty-three children and adolescents with DSM-IV OCD were compared to a reference group of school children (n = 240–336). The basal cortisol rhythm was measured through saliva samples 3 times/day. The cortisol response to a psychological stressor (exposure therapy in the OCD group and a fire alarm in the reference group) was also examined. <i>Results:</i> Compared to the reference group, OCD subjects displayed higher early-morning cortisol values (p = 0.005) with no difference between the late-morning and evening values. The cortisol levels in the OCD group diminished in response to the psychological stressor, compared to a positive response in the reference group (p < 0.001). No relation was found between cortisol and clinical parameters. <i>Conclusion:</i> These results support the idea that HPA hyperactivity, commonly found in adult OCD patients, is also present at an earlier stage of development, with specificity for the early-morning peak.
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| 7. |
- Gustafsson, Per E, 1981-
(författare)
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Psychosocial Stress, Mental Health and Salivary Cortisol in Children and Adolescents
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Stressful experiences and conditions in childhood influence the health and well-being of the growing individual, and can also confer a long-lasting impact into adult life. Delineating the social, mental and biological aspects of stress in children and adolescents is therefore of great concern for human beings. Despite these notions, much knowledge is lacking regarding stress in childhood.This thesis aimed at examining diverse aspects of stress in children and adolescents: associations between social conditions, traumatic life events, mental health, and salivary cortisol as a measure of the activity of a major physiological stress system. Cross-sectional samples included two non-clinical samples of school-aged children (N=240-336) and adolescents (N =400), and two clinical samples of children with obsessive-compulsive disorder (OCD) (N =23) and adolescents who had experienced childhood abuse (N =15). Main measures were salivary cortisol sampled three times a day, and questionnaires to teachers, parents and children with questions about each child’s mental health, traumatic life events and about the socioeconomic situation of the parents.The main findings include observation of 1) higher cortisol levels in children with a moderate level of psychosocial burden (low socioeconomic status, immigrant family, social impairment of mental health problems), 2) higher cortisol levels in children with OCD who also displayed a tendency to decreasing cortisol in the face of an acute stressor, and 3) cortisol was positively related to mental health problems in abused adolescents. Furthermore, the deleterious effect of 4) traumatic events involving a social dimension, interpersonal traumas, and 5) cumulative traumatic events, polytraumatization, on the mental health of children and adolescents was indicated.The findings are discussed with respect to the complex interactions between social, mental and biological aspects of children and adolescents. The consequences of adverse experiences in childhood may represent pathways to future health problems. Consideration of the social circumstances in childhood might in the future guide public health policies and the identification of target groups for preventive interventions as well as leading to improvements in treatment for children exposed to severe stress.
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| 8. |
- Gustafsson, Per E., 1981-, et al.
(författare)
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Sociocultural Disadvantage, Traumatic Life Events, and Psychiatric Symptoms in Preadolescent Children
- 2009
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Ingår i: American Journal of Orthopsychiatry. - : American Psychological Association (APA). - 0002-9432 .- 1939-0025. ; 79:3, s. 387-397
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Tidskriftsartikel (refereegranskat)abstract
- Previous research has demonstrated impact of psychosocial adversity on the mental health of children. This cross-sectional study examined the differential relationships between life-time exposure to interpersonal and non-interpersonal traumatic life events as well as sociocultural factors (family social class and immigrant family), and the level of externalizing versus internalizing symptoms. Participants included 258 children aged 6 to 12 years from two Swedish elementary schools. Information was obtained from their parents by means of questionnaires (a demographic form including information about parental occupation and country of origin, the Strengths and Difficulties Questionnaire and the Life Incidence of Traumatic Events checklist). While controlling for gender, age and the other symptom dimension, the sociocultural factors were associated to internalizing but not to externalizing symptoms. In contrast, traumatic life events and especially interpersonal traumas related to externalizing symptoms but not to internalizing symptoms. These findings provide some support for specificity of psychosocial adversities and for the importance of interpersonal traumas, in the impact on child mental health.
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| 9. |
- Lum, S., et al.
(författare)
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Early detection of cystic fibrosis lung disease: multiple-breath washout versus raised volume tests
- 2007
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Ingår i: Thorax. - : BMJ. - 0040-6376. ; 62:4, s. 341-7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Lung clearance index (LCI), a measure of ventilation inhomogeneity derived from the multiple-breath inert gas washout (MBW) technique, has been shown to detect abnormal lung function more readily than spirometry in preschool children with cystic fibrosis, but whether this holds true during infancy is unknown. OBJECTIVES: To compare the extent to which parameters derived from the MBW and the raised lung volume rapid thoraco-abdominal compression (RVRTC) techniques identify diminished airway function in infants with cystic fibrosis when compared with healthy controls. METHODS: Measurements were performed during quiet sleep, with the tidal breathing MBW technique being performed before the forced expiratory manoeuvres. RESULTS: Measurements were obtained in 39 infants with cystic fibrosis (mean (SD) age 41.4 (22.0) weeks) and 21 controls (37.0 (15.1) weeks). Infants with cystic fibrosis had a significantly higher respiratory rate (38 (10) vs 32 (5) bpm) and LCI (8.4 (1.5) vs 7.2 (0.3)), and significantly lower values for all forced expiratory flow-volume parameters compared with controls. Girls with cystic fibrosis had significantly lower forced expiratory volume (FEV(0.5) and FEF(25-75 )) than boys (mean (95% CI girls-boys): -1.2 (-2.1 to -0.3) for FEV(0.5) Z score; FEF(25-75): -1.2 (-2.2 to -0.15)). When using both the MBW and RVRTC techniques, abnormalities were detected in 72% of the infants with cystic fibrosis, with abnormalities detected in 41% using both techniques and a further 15% by each of the two tests performed. CONCLUSIONS: These findings support the view that inflammatory and/or structural changes in the airways of children with cystic fibrosis start early in life, and have important implications regarding early detection and interventions. Monitoring of early lung disease and functional status in infants and young children with cystic fibrosis may be enhanced by using both MBW and the RVRTC.
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| 10. |
- Gustafsson, Per M., 1952, et al.
(författare)
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Multiple-breath inert gas washout and spirometry versus structural lung disease in cystic fibrosis.
- 2008
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Ingår i: Thorax. - : BMJ. - 1468-3296 .- 0040-6376. ; 63:2, s. 129-34
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A sensitive and valid non-invasive marker of early cystic fibrosis (CF) lung disease is sought. The lung clearance index (LCI) from multiple-breath washout (MBW) is known to detect abnormal lung function more readily than spirometry in children and teenagers with CF, but its relationship to structural lung abnormalities is unknown. A study was undertaken to determine the agreements between LCI and spirometry, respectively, with structural lung disease as measured by high-resolution computed tomography (HRCT) in children and teenagers with CF. METHODS: A retrospective study was performed in 44 consecutive patients with CF aged 5-19 years (mean 12 years). At an annual check-up inspiratory and expiratory HRCT scans, LCI and spirometric parameters (forced expiratory volume in 1 s (FEV1) and maximal expiratory flow when 75% of forced vital capacity was expired (FEF75)) were recorded. Abnormal structure was defined as a composite HRCT score of >5%, the presence of bronchiectasis or air trapping >30%. Abnormal lung function was defined as LCI above the predicted mean +1.96 residual standard deviations (RSD), or FEV1 or FEF75 below the predicted mean -1.96 RSD. Sensitivity/specificity assessments and correlation analyses were done. RESULTS: The sensitivity to detect abnormal lung structure was 85-94% for LCI, 19-26% for FEV1 and 62-75% for FEF75. Specificity was 43-65% for LCI, 89-100% for FEV1 and 75-88% for FEF75. LCI correlated better with HRCT scores (Rs +0.85) than FEV1 (-0.62) or FEF75 (-0.66). CONCLUSIONS: LCI is a more sensitive indicator than FEV1 or FEF75 for detecting structural lung disease in CF, and a normal LCI almost excludes HRCT abnormalities. The finding of an abnormal LCI in some patients with normal HRCT scans suggests that LCI may be even more sensitive than HRCT scanning for detecting lung involvement in CF.
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