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| 2. |
- Bendix, Marie, et al.
(författare)
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Insulin and glucagon in plasma and cerebrospinal fluid in suicide attempters and healthy controls
- 2017
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Ingår i: Psychoneuroendocrinology. - : Elsevier. - 0306-4530 .- 1873-3360. ; 81, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Mental disorders and related behaviors such as suicidality and violence have been associated to dysregulation of e g carbohydrate metabolism. We hypothesized that patients after suicide attempt, compared to healthy controls, would have higher insulin and lower glucagon levels in plasma and cerebrospinal fluid and that these changes would be associated to violent behavior. Twenty-eight medication-free patients (10 women, 18 men), hospitalized after suicide attempt, and 19 healthy controls (7 women, 12 men) were recruited with the aim to study risk factors for suicidal behavior. Psychological/psychiatric assessment was performed with SCID I and II or the SCID interview for healthy volunteers respectively, the Karolinska Interpersonal Violence Scale (KIVS) for assessment of lifetime violence expression behavior, the Montgomery-Asberg-Depression-Scale (MADRS) and the Comprehensive Psychological Rating Scale (CPRS) for symptomatic assessment of depression and appetite. Fasting levels of insulin and glucagon were measured in plasma (P) and cerebrospinal fluid (CSF). Suicide attempters had higher insulin- and lower glucagon-levels in plasma- and CSF compared to controls. Except for P-glucagon these associations remained significant after adjusting for age and/or BMI. Patients reported significantly more expressed interpersonal violence compared to healthy volunteers. Expressed violence was significantly positively correlated with P- and CSF-insulin and showed a significant negative correlation with P-glucagon in study participants. These findings confirm and extend prior reports that higher insulin and lower glucagon levels in plasma and cerebrospinal fluid are associated with suicidal behavior pointing towards a potential autonomic dysregulation in the control of insulin and glucagon secretion in suicidal patients.
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| 3. |
- Bendix, Marie, 1971-
(författare)
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Neuroendocrine studies in patients with affective disorders
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Affective disorders are common and a major cause for increased disability and mortality worldwide. Exogenous stressors and biological variables, including neuroendocrine factors, are assumed to contribute to an increased vulnerability to mood dysregulation. Affective disorders are highly heterogeneous and different neuroendocrine systems may play differential roles in the phenotypic expression of affective disorders in men and women.Aims: The overall aim of this thesis was to study three neuroendocrine systems in relation to underlying behavioral endophenotypes (personality traits, self-directed and interpersonal violence, and psychiatric symptoms) in patients with affective disorders.Methods: In Study I oxytocin plasma levels were assessed in 101 general psychiatric outpatients and followed-up in 36 patients after one month. Patients underwent diagnostic, symptomatic, and personality trait assessments.In Study II insulin and glucagon levels in plasma and cerebrospinal fluid (CSF) were assessed in 28 patients hospitalized after a recent suicide attempt and 19 healthy controls. Study persons were assessed regarding lifetime violence expression, psychiatric diagnoses and symptoms.In Study III serum levels of allopregnanolone, progesterone and estradiol were assessed in 14 women with severe postpartum depression and psychosis who, as previously reported, responded with rapid symptom remission during sublingual estradiol treatment. Hormonal and symptomatic assessment were performed before and after 4 weeks of estradiol treatment. 28 healthy postpartum controls were included for baseline comparison.Results: I) Plasma oxytocin levels were positively associated with personality traits of impulsiveness (monotony avoidance) and negative emotionality (psychic anxiety) with potential gender differences.II) Patients after suicide attempt had higher insulin (plasma and CSF) and lower glucagon levels (CSF) than healthy controls. Insulin levels (plasma and CSF) were higher and glucagon levels (plasma) were lower in patients and controls with higher levels of prior violence expression.III) Serum allopregnanolone decreased in women with postpartum depression and psychosis during estradiol treatment. The ratio between allopregnanolone and progesterone was significantly lower in patients than in healthy controls at baseline and it remained unchanged after symptom remission.Conclusion: Behavioral endophenotypes, rather than categorical diagnoses, of affective disorders were associated with neuroendocrine variation in three different cohorts of patients with affective disorder. Hormonal variation pointed towards an association with trait, rather than state like facets of affective behavior, constituting potential vulnerability markers for affective dysregulation.
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| 4. |
- Björklund, Henrik, et al.
(författare)
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Experiments with Iterative Improvement Algorithms on Completely Unimodal Hypercubes
- 2001
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Completely unimodal (i.e., having a unique local minimum on every face) numberings of many-dimensional hypercubes are abstract versions of different optimization problems, like linear programming, decision problems for games, and abstract optimization problems. In this paper we investigate and compare the behaviors of seven iterative improvement algorithms: 1) the Greedy Single Switch Algorithm (GSSA), 2) the Random Single Switch Algorithm (RSSA), 3) the All Profitable Switches Algorithm (APSA), 4) the Random Multiple Switches Algorithm (RMSA), 5) Kalai-Ludwig's Randomized Algorithm (KLRA), 6) Weighted Random Multiple Switch Algorithm (WRMSA), 7) Weighted Greedy Multiple Switch Algorithm (WGMSA). Our experiments were conducted on all completely unimodal four-dimensional hypercubes and on randomly generated hypercubes of dimensions up to sixteen, Hamiltonian (presumably corresponding to hard problem instances) and non-Hamiltonian. Local-search improvement algorithms 1 and 2 have been investigated earlier, but number 3, 4, 5, 6, and 7 probably not. Algorithm 5 (first time used for completely unimodal hypercubes in this paper) is the only algorithm with the known \emphsubexponential expected worst-case running time. However, the algorithms 1, 3, 4, 6, 7 demonstrate superior behaviors compared to the other two investigated algorithms. This suggests that further theoretical and experimental studies of these algorithms should be carried out.
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| 5. |
- Bondesson, Elisabeth, et al.
(författare)
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Utilization of healthcare and prescription medicines after non-pharmacological interventions for depression - A 3-year register follow-up of an RCT in primary care
- 2022
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Ingår i: Preventive Medicine Reports. - : Elsevier. - 2211-3355. ; 25
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Tidskriftsartikel (refereegranskat)abstract
- Depression is a common, recurrent disorder. There is a need for readily available treatments with few negative side effects, that demands little resources and that are effective both in the short- and long term. Our aim was to investigate the long-term effectiveness of two different interventions; physical exercise and internet-based cognitive behavioural therapy (internet-CBT), compared to usual care in patients with mild to moderate depression in a Swedish primary care setting. We performed a register-based 3-year follow-up study of participants in the randomized controlled trial REGASSA (n = 940) using healthcare utilization and dispensed medicines as outcomes. We found no difference between the three groups regarding proportion of participants consulting healthcare due to mental illness or pain during follow-up. Regarding number of consultations, there was no difference between the groups, except for consultations related to pain. For this outcome both treatment arms had significantly fewer consultations compared to usual care, during year 2-3, the risk ratio (RR) for physical exercise and internet-CBT was 0.64 (95% CI = 0.43-0.95) and 0.61 (95% CI = 0.41-0.90), respectively. A significantly lower proportion of patients in both treatment arms were dispensed hypnotics and sedatives year 2-3 compared to the usual care arm, RR for both physical exercise and internet-CBT was 0.72 (95% CI = 0.53-0.98). No other differences between the groups were found. In conclusion, considering long-term effects, both physical exercise and internet-CBT, being resource-efficient treatments, could be considered as appropriate additions for patients with mild to moderate depression in primary care settings.
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| 6. |
- Islam, Md. Shafiqul, 1984-, et al.
(författare)
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The Effects of Stress Triaxiality on the Neck Initiation and Fracture of High-density Polyethylene (HDPE)
- 2022
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Ingår i: Procedia Structural Integrity. - : Elsevier. - 9781713870302 ; , s. 745-754
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Konferensbidrag (refereegranskat)abstract
- This study analyses the tensile mechanical behaviour and deformation of neck i.e localization initiation, propagation and fracture of injection-moulded polymer composed of high-density polyethylene (HDPE) as a function of initial stress triaxiality. Three different specimen geometries namely i) Simple tension, ii) Plane strain and iii) Shear specimens were punched from injection-moulded HDPE plates and tested experimentally in uniaxial tension to introduce different stress triaxialities. These specimen geometries used are standard for the material characterization of sheet metals. However, for plate polymer materials such specimen geometries have not comprehensively been studied earlier. Standard shear specimen geometry has been further optimized in this work using finite element models to restrict unwanted out-of-plane deformations arising at large deformation. The digital image correlation (DIC) technique is used to acquire the full field deformation and in particular the localized strains in the neck region of the specimens. Based on the major-minor strain paths from DIC-measurements stress triaxiality has been calculated. It is challenging to follow the stochastic pattern at larger local strain in DIC and hence the strain at failure has been measured using orthogonal grid lines on the specimen surface. Finally, strains at neck-initiation and failure at three different stress triaxialities are reported for injection-moulded HDPE in two material orientations. It is observed that within the elastic limit the stress triaxialities obtained from the experimental tests were close to the ideal values found in the literature and neck-initiation strain is strongly dependent on the stress triaxiality. However, as neck initiates and propagates, the triaxialities for all geometries shift closer to the measured value in a simple tension specimen i.e. 0.33 limiting the effect of the initial triaxiality on failure strain.
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| 7. |
- Klemetz, Viktor, et al.
(författare)
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Humanexponering av mikroplast i luft
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- IVL Svenska Miljöinstitutet har fått i uppdrag av Naturvårdsverket att utvärdera och föra resonemang kring hur exponering av mikroplast via luft kan övervakas i Sverige, redovisa lämpliga metoder och kostnader avseende detta samt att undersöka om möjligheterna finns att övervakningen sker inom ramen för pågående nationell luftmiljöövervakning.Ur ett humantoxikologiskt perspektiv bör mätningar göras för partiklar med en aerodynamisk diameter mindre än 10 µm (PM10) respektive 2,5 µm (PM2,5).Mätningarna bör främst ske i tätorter med aktiv pumpad provtagning, och initialt bör mätningar ske kontinuerligt på dygns- eller veckobasis för att lättare kunna fatta mätstrategiska beslut om framtida övervakning av mikroplast avseende mätfrekvens och lämpliga mätperioder under året. Rimligtvis följer halterna av mikroplast samma årsvariation som partikelhalter, vilket innebär att högst halter sannolikt uppmäts på våren. Befintliga mätnätverk rekommenderas att användas.Både för provtagning och analys rekommenderas främst glasfiberfilter, alternativt annat filter som är kompatibelt med mätinstrument på befintliga mätstationer. Vid val av annan filtersort för provtagning bör efterföljande preparering och analys beaktas.Termoanalytiska metoder, så som pyrolys-GC/MS och TED-GC/MS, rekommenderas som analysmetod för mikroplast i luft.Inom den nationella luftövervakningen rapporteras resultaten som viktenhet per kubikmeter luft. Samma mätenhet rekommenderas även för mikroplast, förslagsvis som mg/m3 eller ng/m3 beroende på uppmätt haltnivå. Ett referensbibliotek, vilket är ett paketerat informationsunderlag med kända markörer för olika plaster, krävs för att man i analysen ska kunna identifiera mikroplasterna. Ett beslut måste därmed tas om vilka typer av mikroplast som ska analyseras för att analysresultaten så långt som möjligt ska kunna spegla den totala halten mikroplast i ett prov.Befintlig provtagning inom den nationella luftövervakningen bedöms nödvändigtvis inte påverkas av den utökade analysen av mikroplast förutsatt att typen av filter är kompatibel med provtagningsutrustningen.
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| 8. |
- Kraepelien, Martin, et al.
(författare)
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Cost-effectiveness of internet-based cognitive-behavioural therapy and physical exercise for depression
- 2018
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Ingår i: BJPsych Open. - Cambridge : Cambridge University Press. - 2056-4724. ; 4:4, s. 265-273
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Tidskriftsartikel (refereegranskat)abstract
- Background Both internet-based cognitive-behavioural therapy (ICBT) and physical exercise are alternatives to treatment as usual (TAU) in managing mild to moderate depression in primary care. Aims To determine the cost-effectiveness of ICBT and physical exercise compared with TAU in primary care. Method Economic evaluation of a randomised controlled trial (N=945) in Sweden. Costs were estimated by a service use questionnaire and used together with the effects on quality-adjusted life-years (QALYs). The primary 3-month healthcare provider perspective in primary care was complemented by a 1-year societal perspective. Results The primary analysis showed that incremental cost per QALY gain was (sic)8817 for ICBT and (sic)14 571 for physical exercise compared with TAU. At the established willingness-to-pay threshold of (sic) 21 536 ( pound 20 000) per QALY, the probability of ICBT being cost-effective is 90%, and for physical exercise is 76%, compared with TAU. Conclusions From a primary care perspective, both ICBT and physical exercise for depression are likely to be cost-effective compared with TAU. (c) The Royal College of Psychiatrists 2018.
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| 9. |
- Kroon, Martin, et al.
(författare)
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Anisotropic Elastic-Viscoplastic Properties at Finite Strains of Injection-Moulded Low-Density Polyethylene
- 2018
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Ingår i: Experimental mechanics. - : Springer New York LLC. - 0014-4851 .- 1741-2765. ; 58:1, s. 75-86
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Tidskriftsartikel (refereegranskat)abstract
- Injection-moulding is one of the most common manufacturing processes used for polymers. In many applications, the mechanical properties of the product is of great importance. Injection-moulding of thin-walled polymer products tends to leave the polymer structure in a state where the mechanical properties are anisotropic, due to alignment of polymer chains along the melt flow direction. The anisotropic elastic-viscoplastic properties of low-density polyethylene, that has undergone an injection-moulding process, are therefore examined in the present work. Test specimens were punched out from injection-moulded plates and tested in uniaxial tension. Three in-plane material directions were investigated. Because of the small thickness of the plates, only the in-plane properties could be determined. Tensile tests with both monotonic and cyclic loading were performed, and the local strains on the surface of the test specimens were measured using image analysis. True stress vs. true strain diagrams were constructed, and the material response was evaluated using an elastic-viscoplasticity law. The components of the anisotropic compliance matrix were determined together with the direction-specific plastic hardening parameters. © 2017 The Author(s)
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| 10. |
- Kroon, Martin, et al.
(författare)
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Experimental and numerical assessment of the work of fracture in injection-moulded low-density polyethylene
- 2018
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Ingår i: Engineering Fracture Mechanics. - : Elsevier BV. - 1873-7315 .- 0013-7944. ; 192, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- The fracture mechanics properties of injection-moulded low-density polyethylene (LDPE) sheets were investigated both experimentally and numerically. The total work of fracture was determined experimentally, by means of fracture mechanics testing of sheets of injection-moulded LDPE with side cracks of different lengths. A multi-specimen method, proposed by Kim and Joe (1987), was employed. The total work of fracture was estimated to 13 kJ/m2. The experiments were simulated numerically using the finite element method. Crack growth was enabled by inclusion of a cohesive zone, and the constitutive response of this zone was governed by a traction-separation law. The local (or essential) work of fracture was estimated through numerical analyses, where the initiation of crack growth was simulated and the outcome was compared to the experimental results. The local (i.e. essential) work of fracture was estimated to 1.7 kJ/m2, which is consistent with previous experimental measurements for the material in question. The total work of fracture, retrieved from the present experiments, agreed well with the far field values of the J-integral in the numerical analyses.
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