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- Blohm, My
(författare)
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Treatment of cholelithiasis and acute cholecystitis : surgical safety in gallstone surgery
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- INTRODUCTION: Laparoscopic cholecystectomy is one of the most frequently performed surgical procedures worldwide, with nearly 14,000 operations per year in Sweden alone. Recurrent biliary colic or acute cholecystitis are indications for surgery. Despite being a standardized procedure, complications occur in more than 10% of all operations. This thesis includes five research papers, all of which focus on different aspects of surgical safety in gallstone surgery. PAPER 1: The recommended treatment of acute cholecystitis is acute cholecystectomy during the first hospital admission, but the optimal timing is still under discussion. The aim of the first study was to analyse whether the timing of surgery for acute cholecystitis affects complication rates. A registry-based study, based on the Swedish National Registry for Gallstone Surgery and Endoscopic Retrograde Pancreatography (GallRiks) was performed. We included 87,108 patients undergoing cholecystectomy from 2006 to 2014. Of these operations, 15,760 (18.1%) were performed due to acute cholecystitis. We analysed differences in outcomes related to timing of surgery. The results showed that intra-and postoperative complications, bile duct injuries and 30-and 90-day mortality increased with longer delays. The conclusion is that the optimal timing of surgery seems to be within two days of hospital admission. PAPER 2: Increasing hospital and surgeon volumes have been associated with better outcomes for more complicated procedures. However, it is still unknown whether the annual volume of cholecystectomies affects surgical outcomes. The aim of this study was to investigate whether the surgeon’s and hospital’s annual volume of cholecystectomies has an impact on complication rates and operating time. A registry-based study was conducted based on all cholecystectomies registered in GallRiks between 2006 and 2019. A total of 154,934 patients were analysed: 101,221 (65.3%) elective procedures and 53,713 (34.7%) acute procedures. Low volume was defined as <211 operations per hospital per year and <20 operations per surgeon per year. The correlation between annual volumes and different outcomes was calculated. The conclusion is that high volume hospitals and surgeons have more favourable outcomes in both elective and acute cholecystectomy. PAPER 3: Female and male physicians practice medicine differently but it is still unknown whether female and male surgeons produce different outcomes. The aim of this study was to analyse whether female and male surgeons differ in complication rates and operating times in both elective and acute cholecystectomies. A registry-based study was performed based on all cholecystectomies registered in GallRiks between 2006 and 2019. In total, 150,509 patents were included: 97,755 (64.9%) were elective and 52,754 (35.1%) were acute operations. Procedures were performed by 2,553 surgeons: 849 (33.3%) female surgeons and 1,704 (67.7%) male surgeons. Differences in outcomes and operating times were analysed. The results showed that patients operated on by male surgeons had more surgical complications overall (Odds Ratio (OR) 1.29, 95% CI 1.19- 1.40) including more bile duct injures in elective surgery (OR 1.69, 95% CI 1.22-2.34). In addition, female surgeons had longer operating times; converted less frequently to open surgery in the acute setting and their patients had overall shorter hospital stays. The conclusion is that female surgeons have more favourable outcomes but operate more slowly than male surgeons, in elective and acute cholecystectomies. PAPER 4: An alternative to electrocautery dissection is ultrasonic dissection, which has proven favourable in elective cholecystectomies. The aim of this study was to evaluate the learning curve for ultrasonic fundus-first dissection, in elective laparoscopic cholecystectomy. Surgeons with no previous experience of the technique could participate. Patients were recruited between 2017 and 2019. Sixteen residents and specialists, from eight Swedish hospitals, performed 15 operations each and 240 patients were included. The primary endpoint was dissection time with secondary endpoints being complication rate and the surgeon’s self-assessed performance level. In addition, five of the operations were recorded and the videos were graded by two external surgeons. Associations between the procedural number and the different outcomes were analysed. The results showed that dissection time decreased as experience increased (p=0.001). The technique had a complication rate of 5.8%, comparable to the traditional technique. No correlation between the number of performed procedures and the video-assessment score could be demonstrated. The self-assessed performance level was rated lower in more complicated procedures (p=<0.001). The conclusion is that ultrasonic fundus-first dissection is easy to learn and safe during the learning curve, for both residents and specialists. PAPER 5: Ultrasonic dissection seems to be a safe alternative in elective cholecystectomy, but it is still unclear whether the technique is favourable in acute operations. The aim of this study was to compare electrocautery to ultrasonic dissection in patients with acute cholecystitis. A multicentre, randomized, controlled trial was conducted at eight Swedish hospitals. Eligible participants were patients ≥18 years old, with acute cholecystitis with a duration of ≤7 days. Patients were randomly assigned to either traditional electrocautery or ultrasonic dissection, with a 1:1 allocation. Patients, postoperative caregivers, and follow-up personnel were masked to group assignment. The primary endpoint was the total complication rate with analyses according to intention-to-treat. From September 30, 2019, until March 22, 2023, a total of 300 patients was randomized to electrocautery dissection (n=148) or ultrasonic dissection (n=152). No difference in complication rate was seen between the groups (risk difference (RD) 1.6%, 95% CI − 7.2% to 10.4%, p=0.72). Haemostatic agents were used in 40 (27.0%) of patients assigned to electrocautery and 27 (17.8%) of patients assigned to ultrasonic dissection, (RD 10.6%, 95% CI 1.3%-19.8%, p=0.025). In 13 (8.8%) operations in the electrocautery group the surgeon chose to use ultrasonic dissection mostly due to the perceived higher complexity of the operation. The conclusion is that ultrasonic and electrocautery dissection have comparable risks for total complications in patients with acute cholecystitis. Ultrasonic dissection can be used as an alternative to electrocautery dissection, or as a complement in complicated cases.
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- Harner, Tom, et al.
(författare)
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Air synthesis review : polycyclic aromatic compounds in the oil sands region
- 2018
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Ingår i: Environmental Reviews. - : Canadian Science Publishing. - 1181-8700 .- 1208-6053. ; 26:4, s. 430-468
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Forskningsöversikt (refereegranskat)abstract
- This air synthesis review presents the current state of knowledge on the sources, fates, and effects for polycyclic aromatic compounds (PACs) and related chemicals released to air in the oil sands region (OSR) in Alberta, Canada. Through the implementation of the Joint Canada-Alberta Oil Sands Monitoring Program in 2012 a vast amount of new information on PACs has been acquired through directed monitoring and research projects and reported to the scientific community and public. This new knowledge addresses questions related to cumulative effects and informs the sustainable management of the oil sands resource while helping to identify gaps in understanding and priorities for future work. As a result of this air synthesis review on PACs, the following topics have been identified as new science priorities: (i) improving emissions reporting to better account for fugitive mining emissions of PACs that includes a broader range of PACs beyond the conventional polycyclic aromatic hydrocarbons (PAHs) including, inter alia, alkylated-PAHs (alk-PAHs), dibenzothiophene (DBT), alk-DBTs, nitro-PAHs, oxy-PAHs including quinones and thia-and aza-arenes; (ii) improving information on the ambient concentrations, long-range transport, and atmospheric deposition of these broader classes of PACs and their release (with co-contaminants) from different types of mining activities; (iii) further optimizing electricity-free and cost-effective approaches for assessing PAC deposition (e.g., snow sampling, lichens, passive ambient sampling) spatially across the OSR and downwind regions; (iv) designing projects that integrate monitoring efforts with source attribution models and ecosystem health studies to improve understanding of sources, receptors, and effects; (v) further optimizing natural deposition archives (e.g., sediment, peat, tree rings) and advanced forensic techniques (e.g., isotope analysis, marker compounds) to provide better understanding of sources of PACs in the OSR over space and time; (vi) conducting process research to improve model capabilities for simulating atmospheric chemistry of PACs and assessing exposure to wildlife and humans; and (vii) developing tools and integrated strategies for assessing cumulative risk to wildlife and humans by accounting for the toxicity of the mixture of chemicals in air rather than on a single compound basis.
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- Rinnan, Riikka, et al.
(författare)
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Mineralization and carbon turnover in subarctic heath soil as affected by warming and additional litter
- 2007
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Ingår i: Soil Biology & Biochemistry. - : Elsevier BV. - 0038-0717. ; 39:12, s. 3014-3023
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Tidskriftsartikel (refereegranskat)abstract
- Arctic soil carbon (C) stocks are threatened by the rapidly advancing global warming. In addition to temperature, increasing amounts of leaf litter fall following from the expansion of deciduous shrubs and trees in northern ecosystems may alter biogeochemical cycling of C and nutrients. Our aim was to assess how factorial warming and litter addition in a long-term field experiment on a subarctic heath affect resource limitation of soil microbial communities (measured by thymidine and leucine incorporation techniques), net growing-season mineralization of nitrogen (N) and phosphorus (P), and carbon turnover (measured as changes in the pools during a growing-season-long field incubation of soil cores in situ). The mainly N limited bacterial communities had shifted slightly towards limitation by C and P in response to seven growing seasons of warming. This and the significantly increased bacterial growth rate under warming may partly explain the observed higher C loss from the warmed soil. This is furthermore consistent with the less dramatic increase in the contents of dissolved organic carbon (DOC) and dissolved organic N (DON) in the warmed soil than in the soil from ambient temperature during the field incubation. The added litter did not affect the carbon content, but it was a source of nutrients to the soil, and it also tended to increase bacterial growth rate and net mineralization of P. The inorganic N pool decreased during the field incubation of soil cores, especially in the separate warming and litter addition treatments, while gross mineralized N was immobilized in the biomass of microbes and plants transplanted into the incubates soil cores, but without any significant effect of the treatments. The effects of warming plus litter addition on bacterial growth rates and of warming on C and N transformations during field incubation suggest that microbial activity is an important control on the carbon balance of arctic soils under climate change.
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- Marschall, Gosia
(författare)
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Teacher self-efficacy sources during initial teacher education
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper reports on the role of self-efficacy sources in the development of teacher self- efficacy of four pre-service secondary mathematics teachers. The results revealed that all four self-efficacy sources were significant in the process, particularly for those individuals who were vulnerable. They also indicated that broadening of the current conceptualisation of physiological and affective states, and vicarious experiences as self-efficacy sources is necessary to uncover the nuances and aid understanding of the process of teacher self- efficacy development. Collectively, the results contribute to the field of teacher self-efficacy in new, previously unreported ways.
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