| 1. |
- Andersson, Johan, et al.
(författare)
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Diving response and arterial oxygen saturation during apnea and exercise in breath-hold divers
- 2002
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Ingår i: Journal of applied physiology. - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 93:3, s. 882-886
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Tidskriftsartikel (refereegranskat)abstract
- This study addressed the effects of apnea in air and apnea with face immersion in cold water (10°C) on the diving response and arterial oxygen saturation during dynamic exercise. Eight trained breath-hold divers performed steady-state exercise on a cycle ergometer at 100 W. During exercise, each subject performed 30-s apneas in air and 30-s apneas with face immersion. The heart rate and arterial oxygen saturation decreased and blood pressure increased during the apneas. Compared with apneas in air, apneas with face immersion augmented the heart rate reduction from 21 to 33% (P < 0.001) and the blood pressure increase from 34 to 42% (P < 0.05). The reduction in arterial oxygen saturation from eupneic control was 6.8% during apneas in air and 5.2% during apneas with face immersion (P < 0.05). The results indicate that augmentation of the diving response slows down the depletion of the lung oxygen store, possibly associated with a larger reduction in peripheral venous oxygen stores and increased anaerobiosis. This mechanism delays the fall in alveolar and arterial Po2 and, thereby, the development of hypoxia in vital organs. Accordingly, we conclude that the human diving response has an oxygen-conserving effect during exercise.
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| 2. |
- André, Malin, et al.
(författare)
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Upper respiratory tract infections in general practice: diagnosis, antibiotic prescribing, duration of symptoms and use of diagnostic tests
- 2002
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Taylor & Francis. - 2374-4235 .- 0036-5548 .- 1651-1980. ; 34, s. 880-
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Tidskriftsartikel (refereegranskat)abstract
- A diagnosis/antibiotic prescribing study was performed in 5 counties in Sweden for 1 week in November 2000. As part of this study, the characteristics and clinical management of patients with upper respiratory tract infections (n = 2899) in primary care were analyzed. Almost half of the patients were aged < 15 y and one-fifth of the patients consulted out of hours. Of all patients seeking primary care for upper respiratory tract infections, 56.0% were prescribed an antibiotic. Almost all patients who were given the diagnoses streptococcal tonsillitis, acute otitis media or acute sinusitis were prescribed antibiotics, compared to 10% of patients with common cold or acute pharyngitis. The most frequently prescribed antibiotic was penicillin V (79.2%) and this was even more pronounced out of hours, when the diagnoses otitis media and streptococcal tonsillitis were more frequently used. In patients with common cold and acute pharyngitis, the percentage who received antibiotics increased with increasing length of symptoms and increasing CRP levels. In patients with acute pharyngitis or streptococcal tonsillitis, antibiotics were prescribed less frequently provided streptococcal tests were performed. The management of patients with upper respiratory tract infections in general practice seems to be in good agreement with current Swedish guidelines. However, the study indicates some areas for improvement. The diagnosis of acute sinusitis seems to have been overestimated and used only to justify antibiotic treatment.
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| 3. |
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| 4. |
- Hildingsson, Ingegerd, et al.
(författare)
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Few women wish to be delivered by caesarean section
- 2002
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Ingår i: British Journal of Obstetrics and Gynecology. - : Wiley. - 1470-0328 .- 1471-0528. ; 109:6, s. 618-623
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate how many women wish to have a caesarean section when asked in early pregnancy, and to identify background variables associated with such a wish. DESIGN: National survey. SETTING: Swedish antenatal clinics. POPULATION: 3,283 Swedish-speaking women booked for antenatal care, at approximately 600 Swedish antenatal clinics, during three weeks spread over one year (1999-2000). METHODS: A questionnaire was mailed shortly after the first antenatal visit. MAIN OUTCOME MEASURES: Women's preferences for mode of delivery. RESULTS: 3,061 women completed the first questionnaire, corresponding to 94% of those who consented to participate after exclusion of reported miscarriages. The background characteristics of the study sample were very similar to a one-year cohort of women giving birth in Sweden during 1999. The result showed that 8.2% of the women would prefer to have a caesarean section. A wish for caesarean section was associated with parity, age, civil status, residential area and obstetric history. Women preferring caesarean section were more depressed and worried, not only about giving birth, but also about other things in life. A multivariate logistic regression model showed three factors being statistically associated with a wish for caesarean section: a previous caesarean section, fear of giving birth and a previous negative birth experience. CONCLUSIONS: Relatively few women wish to have a caesarean section when asked in early pregnancy, and these women seem to be a vulnerable group.
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| 5. |
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| 6. |
- Martini, A., et al.
(författare)
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Mating disruption of the pine sawfly Neodiprion sertifer (Hymenoptera. Diprionidae) in isolated pine stands
- 2002
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Ingår i: Agricultural and Forest Enthomology. - : Wiley. - 1461-9555 .- 1461-9563. ; 4:3, s. 195-201
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Tidskriftsartikel (refereegranskat)abstract
- 1. Previous applications of the mating disruption technique to Neodiprion sertifer resulted in decreased numbers of males caught in the treated area but no effect on sex ratio or overall population density. 2. The present study assessed the efficacy of mating disruption against N. sertifer outbreaks in pine stands surrounded by agricultural areas or pasture, and therefore isolated from other infested areas. 3. Pine stands were treated by placing dispensers with an erythro-mixture of the acetate ester of 3,7-dimethyl-2-pentadecanol every 10 m in a grid. 4. The efficacy of this technique was evaluated by comparing the number of males caught in sticky traps baited with synthetic pheromone, and by comparing the sex ratio and the population density of the sawfly in the subsequent generation between treated and control pine stands. 5. The number of males caught within treated areas was significantly lower than in the control area. 6. In the treated pine stands 46% of the egg clusters resulted in male cocoons only, compared to 3% of the clusters in the control stand. 7. A significant reduction of the sawfly population was observed in the treated pine stands. The results contrast to the earlier mating disruption attempts with N. sertifer and can probably be ascribed to the isolation of the experimental stands.
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| 7. |
- Norgren, Magnus, et al.
(författare)
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Aggregation of Lignin Derivatives under Alkaline Conditions. Kinetics and Aggregate Structure
- 2002
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 18:7, s. 2859-2865
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Tidskriftsartikel (refereegranskat)abstract
- The kinetics of kraft lignin (KL) aggregation at alkaline conditions was studied by quasi-elastic light scattering (QELS) and turbidity measurements. Stability ratios (W) for KL were obtained at 70 °C and various concentrations of sodium chloride. By analyzing the early-time evolution data of aggregate growth obtained from QELS, fractal dimensions of flocs formed in both reaction-limited cluster-cluster aggregation regimes and diffusion-limited cluster-cluster aggregation regimes were determined. Correlations between the fractal dimension and the W-ratio were found in accordance to recent studies of a system containing monodisperse polystyrene colloids. By cryogenic transmission electron microscopy, the fractality of KL aggregate structures in the system was also shown. It was seen from stability studies of KL solutions that the effects of specific co- and counterions follow the Hofmeister series. From the outcome of the investigation, different modes of aggregation occurring in a KL system are proposed. Starting from the macromolecular state of KL and evolving through larger aggregates, the KL clusters finally exhibit a supramolecular structure similar to what earlier has been proposed for native softwood lignin.
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| 8. |
- Pettersson, Per O., et al.
(författare)
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Modeling simultaneous saccharification and fermentation of softwood
- 2002
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Ingår i: Applied Biochemistry and Biotechnology. - 0273-2289 .- 1559-0291. ; 98-100, s. 733-746
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Tidskriftsartikel (refereegranskat)abstract
- Simultaneous saccharification and fermentation (SSF) of wood has been modeled for the past 15-20 years, but the substrates used for model evaluation have so far not included pretreated softwood. In the present study, data from lab-scale batch SSF of SO2-impregnated, steam-pretreated spruce chips were used to evaluate a model found in the literature. The model, which was somewhat modified, consists of a number of nonlinear, coupled ordinary differential equations, which were solved numerically. Some parameter values were fitted to data by use of least-squares minimization. A difficulty in parameter estimation was the lack of cellobiose measurements, something that was relieved by adding assumptions about parameter relations. The simulated concentration profiles agreed well with the measured concentrations of glucose and ethanol. It is therefore concluded that the basic model features apply to softwood SSF. The model predicts rate saturation with respect to enzyme concentration at concentrations above 60 FPU/g cellulose, although this was not observed in the experimental data, which only comprised enzyme concentrations up to 32 FPU/g cellulose.
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| 9. |
- Westerberg, Björn, et al.
(författare)
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Optimisation of a dosing strategy for an HC-SCR diesel exhaust after-treatment system
- 2002
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Ingår i: Chemical Engineering Journal. - 1385-8947 .- 1873-3212. ; 87:2, s. 207-217
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Tidskriftsartikel (refereegranskat)abstract
- Several principal aspects and components of an advanced catalytic exhaust after-treatment system for NO, reduction on a heavy-duty diesel truck engine have been systematically examined and evaluated. The after-treatment system consists of de-NO, catalysts, injection of a reducing agent (diesel fuel), and computer programs to model the engine and catalysts in real time. These models are combined with a third program, a strategy, to control the injection of reducing agent during transient operation. Evaluation of the system was performed using the standard European transient cycle (ETC). The benefits and disadvantages of an oxidation catalyst upstream the reductant injection are clarified. Whereas an increased NO2/NO ratio is beneficial at larger reductant dosages, the effects of temperature levelling and delay are detrimental for system performance. The dynamic effect of introducing a strategy for distributing the reducing agent in time is elucidated. The strategy itself is presented and the process of its systematic optimisation is closely followed. Implications of the optimisation are that catalyst temperature is the most important variable in the strategy. Also, a considerable part of the reducing agent should be distributed at low and intermediate temperatures, for utilising an increased NO2/NO ratio. Furthermore, results suggest that a smooth, rather than instantaneous, adjustment of reductant dosage to driving conditions is necessary. Finally, a set-up with two injectors is examined for its potential in the application. It is shown to be of disadvantage for the ETC as a whole, but may not be so at lower exhaust gas flows.
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