| 1. |
- Emilsson, Kent, 1963-
(författare)
-
Mitral annulus motion in left ventricular pumping
- 2001
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis focus on the role of the mitral annulus motion (MAM) versus outer contour changes in the short axis, in left ventricular (LV) pumping. The influence of atrial contraction on LV dimensions and volumes and the relation between MAM and ejection fraction (EF) in sinus rhythm and in atrial fibrillation was also studied.Echocardiography was used in all studies and in the study about circumflex artery motion angiography was also used.In a study including 20 healthy adults the role of MAM, i.e. the systolic shortening of the left ventricle in the long axis, as the main mechanism of LV pumping was confirmed. There was also, however, a significant contribution to the stroke volume from an outer contour decrease in the short axis during systole. At the chordae tendineae level a cross sectional area decrease of 24% was measured. From calculations based on measures of the long axis shortening of the LV, the outer short axis diameter of the LV and calculated stroke volume, a mean systolic cross sectional area decrease of about 6% was found along the whole length of the ventricle. The higher cross-sectional area decrease at the chordae level is thougth to be caused by regional differences.In previous studies the relation between EF and MAM has been assumed to be linear, but in a meta-analysis of 434 patients it was shown that the relation is non-linear and that a linear regression model overestimates EF in the low range of MAM. It was shown that the relation between EF and MAM in adults is influenced by age but only in the normal range of EF or MAM and not in patients with decreased EF (EF <0.5 or MAM < 10mm). The relation was also shown to be influenced by the LV wall thickness.In 20 patients with atrial fibrillation the ratio EF/MAM was shown to be higher than in 20 age- and gender matched patients with sinus rhythm, due to a decrease in MAM, caused by the loss of atrial contraction.The relation between EF and MAM is thus complex and it therefore seems logical not to "translate" MAM to EF. MAM should be used as such related to reference values in the assessment of LV systolic function.In 13 patients who had atrial fibrillation the stroke volume was shown to increase after successful direct-current cardioversion due to an increase in long axis diastolic elongation of the LV and thereby increased diastolic volume, when atrial contraction was regained.In 28 patients the angiographic measure of circumflex artery motion amplitude tended to be higher than MAM in the higher range of amplitudes while the opposite was found in the lower range of amplitudes.In 13 patients with normal EF it was shown that the motion amplitude of a site epicardially at the most basal lateral part of the LV wall was significantly (P < 0.001) higher than endocardially, but in 13 patients with decreased EF (< 0.5) there was no significant difference between the two sites. The motion amplitude epicardially corresponds to the motion amplitude of the circumflex artery.In the 13 patients with normal EF the motion amplitude of the closed mitral valves was significantly lower than the motion amplitude epi- and endocardially during systole, with a rather conic shape of the atrioventricular plane at the onset of systole. In end-systole the different parts of the left atrioventricular plane, the epicardial part, the endocardial part (mitral annulus) and the valves were almost on the same level.
|
|
| 2. |
- Grassl, Peter, 1974, et al.
(författare)
-
Concrete in compression: A plasticity theory with a novel hardening law
- 2002
-
Ingår i: International Journal of Solids and Structures. - 0020-7683. ; 39:20, s. 5205-5223
-
Tidskriftsartikel (refereegranskat)abstract
- This paper deals with the modelling of the behaviour of plain concrete in triaxial compression using the theory of plasticity. The aim is to model the load resistance and the deformation capacity in uniaxial, biaxial and triaxial compression by means of few parameters, which can be determined easily.A novel hardening law based on a non-associated flow rule and the volumetric plastic strain as hardening parameter is combined with a yield surface proposed by Menetrey and William (1995). The novel hardening and softening law differs from a classic strain-hardening law, as instead of the length of the plastic strain vector only the volumetric component of the latter is used as a hardening parameter. Thus, the non-linearity of the plastic potential is utilized to describe the influence of multiaxial compression on the deformation capacity and no additional ductility measure is required.The implementation and calibration of the novel hardening law are discussed. The prediction of the model is compared to results of uniaxial, biaxial and triaxial compression tests. It is shown that with one set of calibration parameters a good prediction of the load resistance and the deformation capacity for all three types of compression tests can be achieved.
|
|
| 3. |
|
|
| 4. |
- Haupt, Dan, et al.
(författare)
-
Hydrocarbons and aldehydes from a diesel engine running on ethanol and equipped with EGR, catalyst and DPF
- 2004
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A commercially available exhaust aftertreatment system, DNO\dx\sT, comprising exhaust gas recirculation (EGR), an oxidative catalyst and a continuously regenerating diesel particulate filter (DPF) were tested. The test object was a 9-liter, ethanol-fueled diesel engine from Scania equipped with turbocharger and aftercooler. A similar diesel engine from Scania, but running on ordinary Swedish diesel fuel, was used as a reference and a reminder of "the state of the art." The tests involved two different ethanol fuels containing various ignition improvers, Beraid 3540 and rapeseed methyl ester. Test conditions for the engines were those specified in the European Stationary Cycle (ESC). The aftertreatment system reduced the emissions of HC, CO and NO\dx, down to 0.15, 0.04 and 2.54 g/kWh, respectively, while the estimated particle mass was reduced by 67%. Actually, by using the DNO\dx\sT system, the engines became Euro IV engines regarding the emissions of HC, CO and NO\dx. The ethanol-fueled engine without EGR, catalyst or DPF emitted approximately 1.6 times more formaldehyde and 9.8 times more acetaldehyde than the diesel engine. However, the emission of acrolein was only 0.47 times the emission of acrolein from the diesel engine. When the ethanol-fueled engine was equipped with DNO\dx\sT, a significant reduction of the emissions of aldehydes was obtained. The emissions of acrolein, formaldehyde and acetaldehyde were reduced by 56%, 87% and 95%, respectively. An even higher reduction was observed when the system was connected to the diesel engine. Fifteen different hydrocarbons (alkanes, olefins and monoaromates) were also identified. The diesel-fueled engine, without any exhaust aftertreatment devices, emitted approximately twice as much hydrocarbon than the ethanol-fueled engine, also without any exhaust aftertreatment devices. However, there were also qualitative differences. Three hydrocarbons, namely propene, ethene and benzene, accounted for 77% of the hydrocarbons emitted from the diesel-fueled engine, while acetylene, ethene and benzene, made up only 53% of the hydrocarbons emitted from the ethanol-fueled engine. When connecting the system to the engines, a difference was observed; the reduction of analyzed hydrocarbon emissions was approximately 90% for the diesel-fueled engine, but only 47% for the ethanol-fueled engine. The studied aftertreatment system has been developed and optimized for the diesel-fueled engine. This fact is reflected in the powerful reduction of hydrocarbons, aldehydes, particles and NO\dx that is obtained when connecting the system to the diesel-fueled engine. Nevertheless, a significant reduction is also obtained when connecting the system to the ethanol-fueled engine. Test results indicate that it should be possible to better optimize the system for the ethanol engine. It is also, probably, necessary to exchange the catalyst in the system. Thereby, an even higher reduction of unregulated and regulated emissions should be obtained
|
|
| 5. |
- Haupt, Dan, et al.
(författare)
-
Investigating the potential to obtain low emissions from a diesel engine running on ethanol and equipped with EGR, catalyst and DPF
- 2004
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Experiments were performed to investigate the potential to achieve low emissions from a diesel engine fueled by ethanol and equipped with a commercially available exhaust after-treatment device, DNO\dx\sT from STT Emtec. The DNO\dx\sT system includes exhaust gas recirculation (EGR) catalysts and a continuously regenerating diesel particulate filter (DPF). Two Euro III classified 9-liter turbocharged, after-cooled diesel engines from Scania were used for the task. One engine was fueled by ethanol and the other by Swedish diesel fuel, EC1. Engine operating conditions of a 22-mode test cycle, including the 13 modes of the European Stationary Cycle (ESC cycle), were used for the tests. The emissions of NO\dx and HC were small for the ethanol-fueled engine, 3.48 and 0.53 g/kWh, respectively, while the emission of CO was higher, 2.07 g/kWh. Estimations of emitted particle mass were calculated by using the software supplied in the Scanning Mobility Particle Sizer (SMPS). The estimations showed that the ethanol engine emitted only \mA1/10 of the particle mass emitted by the diesel-fueled engine. A powerful reduction of the regulated emissions was obtained when equipping the ethanol engine with EGR, catalyst and DPF. The emissions of HC, CO and NO\dx decreased down to 0.15, 0.04 and 2.54 g/kWh, respectively, while the estimated particle mass was reduced by 67%. Actually, by using the aftertreatment system, the engine became a Euro IV engine regarding the emissions of HC, CO and NO\dx. The system worked even better with the diesel-fueled engine. The NO\dx emission was reduced by approximately 33% and the estimated particle mass by more than 99%. Calculations showed that the EGR ratio was higher for the diesel engine than for the ethanol engine. Consequently, by applying a higher EGR ratio for the ethanol engine an additional reduction of the NO\dx emissions should be obtained. The results indicate that very low NO\dx and particle emissions could be obtained for an ethanol-fueled diesel engine by using the right aftertreatment equipment. Future studies should investigate the possibility to increase the EGR ratio further. The investigations also underline the need for development of a special particulate filter for ethanol engines.
|
|
| 6. |
- Lindholm, Elisabet, 1946, et al.
(författare)
-
Effects of recombinant erythropoietin in palliative treatment of unselected cancer patients
- 2004
-
Ingår i: Clinical cancer research. - 1078-0432. ; 10:20, s. 6855-64
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The purpose is to evaluate relationships between objectively assessed exercise capacity and subjectively assessed scoring of physical functioning and well-being after erythropoietin treatment in cancer patients on palliative care. EXPERIMENTAL DESIGN: Unselected cancer patients (n = 108) who experienced progressive cachexia were randomized to receive either anti-inflammatory treatment alone (indomethacin) or recombinant erythropoietin plus indomethacin to prevent the appearance of disease-induced anemia and thereby protect patients' exercise capacity. Follow-up investigations of nutritional status, exercise capacity, and health-related quality of life assessed by SF-36 and the European Organization for Research and Treatment of Cancer QLQ-C30 were compared. RESULTS: Effective treatment by erythropoietin on top of basal whole body anti-inflammatory treatment was confirmed and indicated by time course changes of biochemical, physiologic, and nutritional objectives, whereas individual self-reported scoring of physical functioning and general health did not indicate a clear-cut effectiveness, particularly at moderately subnormal hemoglobin levels. CONCLUSIONS: Discrepancies between objective and subjective self-reported measures may be either fundamental or indicate scoring limitations for evaluation of therapeutic results. Present results demonstrate a clinical benefit of erythropoietin treatment in cancer patients with subnormal to normal hemoglobin levels, whereas the patients' own subjective scoring was insufficient to sense such improvements. The discrepancy may be either fundamental or methodological but emphasizes the importance to document therapeutic outcome in both subjective and objective perspectives in palliative care of cancer patients.
|
|
| 7. |
- Lundholm, Kent, 1945, et al.
(författare)
-
Evidence that long-term COX-treatment improves energy homeostasis and body composition in cancer patients with progressive cachexia
- 2004
-
Ingår i: International journal of oncology. - 1019-6439. ; 24:3, s. 505-12
-
Tidskriftsartikel (refereegranskat)abstract
- Cancer patients lose weight due to negative energy balance because of insufficient appetite and inappropriately high energy expenditure. Host and tumor derived cytokines and more recently eicosanoids have been held responsible as mediators. Accordingly, observations in animal experiments and short-term clinical trials in selected groups of cancer patients, have implied that cyclo-oxygenase (COX) blockade can improve host metabolism and well-being, and long-term COX-treatment of unselected groups have implied improved survival. The aim of this study was to search for evidence that long-term COX-treatment improves energy and cardiovascular homeostasis in unselected weight-losing cancer patients. A retrospective case control analysis was performed on a data-base material collected consecutively. Weight-losing untreated cancer patients had elevated resting energy expenditure compared to undernourished non-cancer patients (23.3+/-0.1, n=702 vs 20.9+/-0.3 kcal/kg/day, n=132, p<0.001). This difference became significantly reduced by long-term indomethacin treatment (p<0.003). Heart rate was correspondingly decreased, while systolic blood pressure increased following indomethacin treatment of cancer patients (p<0.006-0.008). Total body fat was more preserved (p<0.005), while lean body mass was uninfluenced by long-term indomethacin to cancer patients. All these beneficial effects were parallel to a decrease in systemic inflammation (C-reactive protein, erythrocyte sedimentation rate) in cancer patients on indomethacin (p<0.0004). Systemic inflammation and resting energy metabolism predicted weight loss in progressive cancer (p<0.0001). Our data support the concept that COX-treatment may offer beneficial metabolic effects to weight-losing cancer patients by attenuation of resting metabolism and improved appetite due to decreased systemic inflammation.
|
|
| 8. |
- Lundholm, Kent, 1945, et al.
(författare)
-
Palliative nutritional intervention in addition to cyclooxygenase and erythropoietin treatment for patients with malignant disease: Effects on survival, metabolism, and function
- 2004
-
Ingår i: Cancer. - : Wiley. - 0008-543X. ; 100:9, s. 1967-77
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The role of nutrition in the palliative treatment of patients with malignancy-related cachexia is unclear. The goal of the current study was to determine whether specialized, nutrition-focused patient care could improve integrated whole-body metabolism and functional outcome in unselected weight-losing patients with malignant disease who were receiving systemic antiinflammatory (cyclooxygenase [COX]-inhibitory) treatment along with erythropoietin (EPO) support. METHODS: Three hundred nine patients with malignant disease who experienced progressive cachexia due to solid tumors (primarily gastrointestinal lesions) were randomized to receive a COX inhibitor (indomethacin, 50 mg twice daily) and EPO (15-40,000 units per week) along with specialized, nutrition-focused patient care (oral nutritional support and home total parenteral nutrition [TPN]) provided on a patient-by-patient basis to attenuate inflammation, prevent anemia, and improve nutritional status. Control patients received the same indomethacin and EPO doses that study patients received without the added nutritional support. All patients were treated and followed until death. Biochemical assays (blood, liver, kidney, and thyroid), nutritional state assessment (food intake and body composition), and exercise testing with simultaneous measurement of whole-body respiratory gas exchange before and during exercise were performed before the start of treatment and then at regular intervals during the treatment period (every 2-30 months after treatment initiation). Statistical analyses were performed on 'intention-to-treat' and 'as-treated' bases. RESULTS: Home TPN was provided to approximately 50% of the study patients without severe complications. Over the entire observation period, rhEPO prevented the development of anemia in both study patients and control patients. Intention-to-treat analysis revealed an improvement in energy balance for nutritionally supported patients (P < 0.03); no other significant differences in outcome between study patients and control patients were observed. As-treated analysis demonstrated that patients receiving nutrition experienced prolonged survival (P < 0.01), which was accompanied by improved energy balance (P < 0.001), increasing body fat (P < 0.05), and a greater maximum exercise capacity (P < 0.04). A trend toward increased metabolic efficiency at maximum exercise (P < 0.06) for study patients relative to control patients also was observed. CONCLUSIONS: The results of the current study strongly support that nutrition is a limiting factor influencing survival and that nutritional support protects integrated metabolism and metabolic function in patients with progressive cachexia secondary to malignant disease.
|
|
| 9. |
- Nord, Kent, et al.
(författare)
-
Particulate emissions from an ethanol-fueled, heavy-duty diesel engine equipped with EGR, catalyst and DPF
- 2004
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Ethanol-fueled engines are considered to be low particulate-emitting engines. This study was performed to investigate the potential to achieve even lower particulate emission if a 9-liter Scania diesel engine, running on ethanol fuel is equipped with emission control. State-of-the-art technology in emission control was applied, e.g., exhaust gas recirculation, EGR, catalysts and a continuous regenerating particle filter, DPF. Particulate emissions were compared with emissions from a 9-liter Scania diesel engine from the same engine family, running on Swedish environmental class 1 diesel fuel. Tailpipe measurements of particle size and distribution were performed with a scanning mobility particle sizer, SMPS, instrument together with filter sampling. An evaluation of SMPS measurements was performed for test conditions specified according to a 22-mode test cycle, which included the test modes in the European Stationary Cycle, ESC. Calculated weighted particle mass from SMPS data, and in accordance with ESC, showed that the ethanol engine without emission control emitted approx. 1/12 of particle mass compared to the diesel engine. Weighted particulate emissions were reduced by approx. 96%, when the engine was fitted with EGR and DPF. The reduction of weighted particulate emissions was even higher when the diesel engine was fitted with EGR and DPF, as high as 99%. Particle size and distribution measurements revealed that particles emitted from the ethanol engine mainly consisted of ultrafine particles (\ml100 nm), usually had a mean diameter of about 30 nm, while particles emitted from the diesel engine usually had mean diameters of about 60-70 nm and sizes going up to approx. 300 nm. Filter samples analyzed by Scanning electron microscopy and energy dispersive x-ray analysis SEM/EDX showed that the particles, both from the ethanol-fueled engine and the diesel-fueled engine mainly consisted of carbon and that they agglomerated, dependent upon running conditions, chainlike or clot-wise. Raman spectroscopy confirmed that the same elemental carbon was present in particles emitted from diesel and ethanol-fueled engines. The investigations showed that the system used, with EGR and DPF combined, is highly effective in reducing particulate emissions from ethanol- and diesel-fueled diesel engines. A general conclusion is also that the ethanol-fueled engine, equipped with emission control system or not, emitted lower particle mass, smaller particle sizes and approx. the same or a greater number of particles in the emissions than the diesel-fueled engine.
|
|
| 10. |
- Wiberg, Kent, et al.
(författare)
-
Determination of the content and identity of lidocaine soluions with UV-visible spectroscopy and multivariate calibration
- 2001
-
Ingår i: The Analyst. - : Royal Society of Chemistry (RSC). - 0003-2654 .- 1364-5528. ; 126:7, s. 1142-1148
-
Tidskriftsartikel (refereegranskat)abstract
- A method is proposed for the determination of the content and identity of the active compound in pharmaceutical solutions by means of ultraviolet-visible (UV–Vis) spectroscopy, orthogonal signal correction (OSC) and multivariate calibration with soft independent modelling of class analogy (SIMCA) classification and partial least squares (PLS) regression. The content was determined with PLS regression and the identity with PLS regression and SIMCA classification. The method was tested on the local anaesthetic compound lidocaine. For the validation, external test sets of both manufactured sample solutions and samples from a stability study were used. For comparison with this new method, liquid chromatography was used as a reference method. The results show that in respect of accuracy, precision and repeatability, the new method is comparable to the reference method. The main advantage over liquid chromatography is the much shorter time of analysis and the simpler analytical procedure. An estimate of the analysis time saved with the proposed method compared with using liquid chromatography, together with practical considerations, is given.
|
|
