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- Samuelsson, Annika, 1964-
(författare)
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The faecal flora : a source of healthcare-associated infections and antibiotic resistance
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Healthcare-associated infections (HAI) are important causes of mortality and morbidity, and antibiotic treatment is often necessary. Development and availability of new antibiotics are closely followed by development of resistance among microorganisms. During antibiotic therapy, a fraction of the antibiotic given is found in the gut. The human gut is an important reservoir of bacteria. Microorganisms residing or passing the gut is referred to as the gut flora or microbiota. The results of this thesis showed spread of Enterococcus spp between patients on a general intensive care unit, causing septicaemia. After improved hygiene, reorganisation of rooms and thorough cleaning of the unit, together with revision of antibiotic strategy, the incidence of septicaemia with Enterococcus spp fell. Investigation of patients treated for acute intra-abdominal infections showed a shift in the aerobic faecal flora from antibiotic-susceptible Enterobacteriaceae spp towards Enterococcus faecium, yeasts and species of Enterobacteriaceae more resistant to antibiotics, after antibiotic treatment and hospital care. Investigation of recurrent outbreaks of Serratia marcescens sepsis in patients admitted to a neonatal intensive care unit showed different clones with each outbreak. Multiple hygiene interventions and revision of antibiotic strategy subsequently obviated recurrent outbreaks of sepsis, but spread of S. marcescens was not reduced until compliance with basic hygiene guidelines remained stable above 80%. We also found that low gestational age at birth, ventilator treatment and central venous or umbilical catheters are independent risk factors for late onset sepsis. Investigation of the faecal microbiota in patients with acute appendicitis or diverticulitis revealed that disturbance of the faecal microbiota already existed on admission, with higher numbers of Enterobacteriaceae and less Bacteroides, Faecalibacterium, Ruminococcus and Prevotella prior to antibiotic treatment and hospitalisation, than the control population. After treatment and hospitalisation diversity increased significantly in the diverticulitis group, approaching the healthy controls in composition.
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| 2. |
- Jonasson, Erik
(författare)
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Modeling and analysis of offshore hybrid power parks
- 2024
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the past decade, the global share of fossil-based electricity generation has decreased from 67% to 61% in favor of renewable alternatives. To achieve global goals, a continued extensive expansion of electricity generation from renewable energy sources is necessary. Offshore wind power is expected to constitute a significant portion of this additional generation capability. However, intermittent energy generation like wind or solar power has negative impacts on the electricity grid due to its inherently variable and non-dispatchable nature. Furthermore, energy generation from renewable energy sources is characterized by low utilization and requirement of large geographical areas.One way to mitigate several of these negative aspects is by co-locating energy sources with complementary characteristics. Combining different types of complementary renewable energy sources can reduce overall variability, increase transmission system utilization, and decrease land use. This thesis addresses several aspects of grid integration of offshore co-located energy sources, primarily, offshore wind power, floating solar power, and wave power. One question analyzed in several of the included studies is the optimal combination of energy sources for co-location to achieve the lowest variability.Another aspect investigated is the capacity credit for a hybrid park consisting of co-located energy generation compared to the capacity credit for a wind farm. In a case study for the Netherlands, the capacity credit for combined wave and wind power is higher than for wind power alone. Additionally, the complementarity of renewable energy sources is analyzed and explained.
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