Publikationer från Uppsala Universitet
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Development of permeable networks by viscous-brittle deformation in a shallow rhyolite intrusion. Part 2 : Microstructural analysis
No full textVolcanic and magmatic outgassing mechanisms can determine eruptive behavior of shallow silicic magma bodies. Most outgassing mechanisms proposed take place along conduit margins, where the highest strain rates drive ascending magma to brittle failure. However, these mechanisms do not account for outgassing large volumes of magma away from the conduit walls. Here, we present a continuum of porosity preserved in the microcrystalline rhyolitic Sandfell laccolith, Eastern Iceland. Three stages in the continuum are described: porous flow bands, pore channels, and fracture bands. These deformation features are present throughout the entire exposed volume of the Sandfell laccolith in meter-long band geometries, ranging from mm- to dm-scale thickness, and interlayered with coherent, undeformed rhyolite. Using microstructural analytical methods and drawing on the result of previous experimental studies, we show that emplacement-related deformation induced strain partitioning around a crystal content of 45 % that resulted in the segregation of melt-rich and melt-poorer flow bands. Subsequent deformation induced by continued magma emplacement caused strain partitioning in the melt-rich flow bands. Depending on strain rate, different types of deformation features developed, through dilation or porosity redistribution (porous flow bands), cavitation (pore channels), or tensile fracture (fracture bands). Porous flow bands have permeability values ∼4 orders of magnitude higher than undeformed rhyolite. Pore channels and fracture bands have much larger length scales, and so permeability increases dramatically in those systems. Hence, the abundance and interconnectivity of deformation features preserved in the Sandfell laccolith provided an efficient outgassing mechanism for the bulk of the intrusion. Outgassing due to viscous-brittle magma deformation during magma emplacement should therefore be considered for crystal-rich magmas, e.g., during effusive lava dome extrusion
Evaluation of hand-assisted laparoscopic surgery of small intestinal neuroendocrine tumours as an alternative surgical treatment to open surgery
No full textPurpose Small intestinal neuroendocrine tumours (SI-NETs) are the most common malignancy of the small bowel. Curative treatment is surgical, with exploratory laparotomy considered the standard approach. This study aimed to assess the outcomes of minimally invasive surgery compared to open approach for SI-NETs at the Endocrine surgical unit at Uppsala University Hospital. Methods This retrospective cohort study included patients who underwent surgery for SI-NET between 2013 and 2023 at Uppsala University Hospital. Variables such as operative time, length of hospital stay, use of analgesia and radicality were compared between groups of patients operated on before and after 2019, when hand-port assisted laparoscopic surgery (HALS) for SI-NETs was introduced at our unit. Outcomes were further compared between open and hand-port assisted laparoscopic approaches. The primary outcome was the rate of radicality achieved for stage II-III patients. Secondary outcomes included operative time, the length of hospital stay and the use of epidural and patient-controlled analgesia. Results Of 97 patients, 58 (59.8%) underwent open surgery and 39 (40.2%) underwent hand-port assisted laparoscopic surgery. There was no significant difference in operative time (121 min [91.3-150.3] vs 108 min [83-141]), length of hospital stay, 6 days [4-7] vs 5 days [4-8]), and surgical radicality in patients with stage II-III, 85.2% vs 100%, (p = 0.079). 86.2% of patients with explorative laparotomy required epidural analgesia compared to only 23.1% with HALS (p < 0.001). Conclusion Hand-port assisted laparoscopic surgery of SI-NETs is a feasible approach that preserves radical resection while enhancing postoperative recovery, with a lower requirement of epidural analgesia
HLA-B27 has wide clinical impact on juvenile idiopathic arthritis - Eighteen years of follow-up in the population-based Nordic Juvenile Idiopathic Arthritis Cohort
No full textObjective: We have previously shown that HLA-B27 was negatively associated with remission status eight years after the onset of juvenile idiopathic arthritis (JIA). We now aimed to study the associations of HLA-B27 with clinical features and disease outcomes 18 years after the onset of JIA. Methods: We studied 434 patients from the population-based Nordic JIA cohort. Demographic and clinical data, including remission status, were collected consecutively at baseline, eight years after disease onset, and 18 years after disease onset and presented in relation to HLA-B27 status. Results: The HLA-B27 status was available for 416 of the 434 participants (96%) and was positive for 93 participants (22.4%), more often in men (P = 0.01). The sacroiliac, hips, and subtalar joints were more frequently involved in individuals who were HLA-B27 positive than in individuals who were HLA-B27 negative. In almost half of the individuals with HLA-B27 positivity and uveitis, the uveitis was asymptomatic. Uveitis, inflammatory back pain, sacroiliitis, arthritis in hip, tarsal, and subtalar joints, and enthesitis during the disease course were all associated with a lower rate of remission off medication. HLA-B27 positivity was significantly associated with a higher risk of not being in remission off medication after 18 years (odds ratio [OR] 2.6), especially in men (OR 5.6). Conclusion: Clinical features related to spondylarthropathies were more common in patients who were HLA-B27 positive and associated with worse outcomes and nonremission 18 years after disease onset, particularly in men. Our results underline the adverse impact of having HLA-B27 positivity on long-term outcomes in individuals with JIA
Självmord och social isolering i Sverige : En kvantitativ studie på makronivå
No full textSjälvmordstalen i Sverige har de senaste decennierna stått relativt stilla, trots aktivt preventionsarbete. Männen står för två av tre självmord, vilket är ett globalt mönster. Studiens syfte är att undersöka om social isolering, genom arbetslöshet, skilsmässor och befolkningstäthet kan påverka självmordstalen över tid i Sverige. Tidigare forskning visar olika resultat över sambandet mellan social isolering och suicidala utfall. För att undersöka sambandet använts Durkheims teori om egoistiska självmord som handlar om hur väl individen är integrerad med sin omgivning och familj. Studien bygger på data från SCB och Socialstyrelsen mellan åren 1997 och 2023. Analysen är genomförd med pooled timeseries och differentierade data. Resultaten visar att arbetslöshet, skilsmässor och befolkningstäthet inte har någon påverkan på självmordstalen i Sverige. Det finns heller inga könsskillnader hur variablerna påverkar självmordstalen. Resultatet visar att andra faktorer spelar en stor roll när det kommer till självmord.
Chronic, Shunt-Dependent Hydrocephalus in Aneurysmal Subarachnoid Hemorrhage : Incidence, Risk Factors, Clinical Phenotypes, and Outcome
No full textObjective The main aim was to determine the incidence, risk factors, clinical phenotypes, and response to shunt surgery in chronic, shunt-dependent hydrocephalus (SDHC) after aneurysmal subarachnoid hemorrhage (aSAH). Methods In this observational, single-center study, 849 aSAH patients treated at Uppsala University Hospital between 2008–2018 were included. Variables on demography, injury severity, treatments, chronic hydrocephalus presentation, and outcome were evaluated. Results In total, 107 (13%) patients were treated with a shunt due to SDHC. In multivariate logistic regressions, risk factors for SDHC were worse neurologic (World Federation of Neurosurgical Societies) grade, larger ventricles (Evans index) at admission, the need to insert an external ventricular drain (EVD), decompressive craniectomy, and complications with meningitis. Six different SDHC phenotypes were identified: impeded neurological recovery (55%), Hakim-Adams syndrome (17%), high-pressure symptoms (13%), failed EVD removal (8%), external brain herniation after decompressive craniectomy (DC; 6%), and subdural hygroma (1%). The former 3 groups significantly improved in modified Rankin Scale (mRS) and 87%–100% exhibited subjective symptomatic relief. There was no significant change in mRS for the latter 3 groups, but 60%–100% experienced some subjective relief postoperatively. Conclusions Chronic SDHC was a common complication after aSAH, particularly in patients with severe primary brain injury, acute hydrocephalus, and treatment-related factors. The condition presents with distinct clinical phenotypes, which may influence treatment response. Recognizing these phenotypes could aid in optimizing patient selection and expectations for shunt surgery outcomes
Foreword to the focus issue : frontline research on biomaterials-based bioengineering for future therapy
No full textRepresentationen av kvinnor och män i läroböcker i historia : En kvantitativ och kvalitativ bildanalys
No full textStudien undersöker representationen av män och kvinnor under vikingatiden i fyra läroböcker i historia för grundskolans årskurs 4. Syftet med denna studie är att undersöka män och kvinnors representation i historieläroböckers bilder samt att identifiera och konkretisera de genusföreställningar som uttrycks i dessa bilder. Besvarandet av syftet sker med användning av kvantitativ och kvalitativ metod. De teoretiska utgångspunkterna tar avstamp i Hirdmans genuskontrakt och genussystem samt Marners semiotiska bildanalys. Resultatet av analysen visade att kvinnor är underrepresenterade både kvantitativt och kvalitativt i de undersökta läroböckerna. Vidare framställs kvinnorna i huvudsak som passiva och omhändertagande. Männen framkommer mer frekvent och framställs i roller som krigare och i maktpositioner med egenskaper som stark, arg och krigslysten. Dessa resultat ligger i linje med tidigare forskning som visar att traditionella könsmönster reproduceras i läromedel i historia. Detta är viktigt att undersöka eftersom elever påverkas av läroböckers innehåll. Alla elever ska ges möjlighet att tillhandahålla en historisk referensram men på grund av underrepresentationen av kvinnor har flickor svårare att relatera till historieämnet.
Search for lepton number violating decays of Ds+ → h-h0e+e+
No full textBased on 7.33 fb(-1) of e(+)e(-) collision data collected by the BESIII detector operating at the BEPCII collider at center-of-mass energies from 4.128 to 4.226 GeV, a search for the Majorana neutrino nu(m) is conducted in the lepton-number-violating decays of D-s(+) -> h(-)h(0)e(+)e(+). Here, h(-) represents a K- or pi(-), and h(0) represents a pi(0), K-S(0) or phi. No significant signal is observed, and the upper limits of their branching fractions at the 90% confidence level are determined to be B(D-s(+) -> phi pi(-)e(+)e(+)) < 6.9 x 10(-5), B(D-s(+) -> phi K(-)e(+)e(+)) < 9.9 x 10(-5), B(D-s(+)-> K-S(0)pi(-)e(+)e(+)) < 1.3 x 10(-5), B(D-s(+) -> K(S)(0)K(-)e(+)e(+)) < 2.9 x 10(-5), B(D-s(+) -> pi(-)pi(0)e(+)e(+)) < 2.9 x 10(-5) and B(D-s(+) -> K-pi(0)e(+)e(+)) < 3.4 x 10(-5). The Majorana neutrino is searched for with different mass assumptions within the range [0.20, 0.80] GeV/c(2) in the decay of D-s(+) -> phi e(+)nu(m) with nu(m) -> pi(-)e(+), and the upper limits of the branching fractions at the 90% confidence level are at the level of 10(-5)-10(-2), depending on the mass of the Majorana neutrino.For complete list of authors see http://dx.doi.org/10.1007/JHEP01(2025)109</p
Defect investigation of undoped wide bandgap materials : Comparison between charge transient spectroscopy (QTS) and inverse Laplace QTS
No full textUnderstanding the electrically active defects and impurities in semiconductors, especially in intrinsic or unintentionally doped wide bandgap materials, still remains a challenge. Here, time-of-flight (ToF) measurement using a solid state light source (355 and 213 nm) was performed on intrinsic silicon carbide and single-crystalline diamond. The charge transient spectroscopy (QTS) and the inverse Laplace (IL) QTS methods were applied to analyze the ToF results. Using these methods, we were able to trace the existing impurities in both materials. However, ILQTS proved to be more sensitive, with higher resolution for detection of existing multiple defects. The results suggest that this system can successfully be employed to investigate electrically active impurities at different energy states in highly resistive and undoped materials