| 1. |
- Andersson, Pia, et al.
(författare)
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Oral health problems in elderly rehabilitation patients
- 2004
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Ingår i: International Journal of Dental Hygiene. - : Wiley-Blackwell. - 1601-5029 .- 1601-5037. ; 2:2, s. 70-77
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Tidskriftsartikel (refereegranskat)abstract
- A combination of poor oral hygiene and dry mouth may be hazardous to the oral health status. However, systematic assessments in order to detect oral health problems are seldom performed in the nursing care of the elderly. The aims of this study were to investigate the occurrence of oral health problems measured using the Revised Oral Assessment Guide (ROAG) and to analyse associations between oral health problems and age, gender, living conditions, cohabitation, reason for admission, number of drugs, and functional and nutritional status. One registered nurse performed oral health assessments using ROAG in 161 newly admitted elderly patients in rehabilitation care. Oral health problems were found in 71% of the patients. Thirty per cent of these patients had between four and eight problems. Low saliva flow and problems related to lips were the most frequent oral health problems. Problems in oral health status were significantly associated with presence of respiratory diseases (problems with gums, lips, alterations on the tongue and mucous membranes), living in special accommodation (low saliva flow, problems with teeth/dentures and alterations on the tongue), being undernourished (alterations on the tongue and low saliva flow) and being a woman (low saliva flow). The highest Odds ratio (OR) was found in problems with gums in relation with prevalence of respiratory diseases (OR 8.9; confidence interval (CI) 2.8–27.8; P < 0.0005). This study indicates the importance of standardised oral health assessments in order to detect oral health problems which can otherwise be hidden when the patients are admitted to the hospital ward.
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| 2. |
- Murin, L.I., et al.
(författare)
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Isotopic effects on vibrational modes of thermal double donors in Si and Ge
- 2001
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 308-310, s. 290-293
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Tidskriftsartikel (refereegranskat)abstract
- The local vibrational modes of thermal double donors in Si and Ge are investigated by FTIR and ab initio modelling. At most, two oxygen modes are detected from each donor, which exhibit regular shifts with increasing donor number. By using mixtures of 16O and 18O, it is found that in Si the upper band does not yield any new modes suggesting that any oxygen atom is decoupled from any other. However, the lower frequency bands exhibit unique mixed modes proving for the first time that oxygen atoms are coupled together and in close spatial proximity. Ab initio calculations demonstrate that the modes and their isotopic shifts are consistent with a model involving two parallel chains of oxygen atoms linking second neighbour Si atoms, terminated by O-atoms close to the normal position for interstitial O. © 2001 Elsevier Science B.V. All rights reserved.
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| 3. |
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| 4. |
- Andersson, Margareta A. T., et al.
(författare)
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Optimisation of ladle slag composition by application of sulphide capacity model
- 2000
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Ingår i: Ironmaking & steelmaking. - : Informa UK Limited. - 0301-9233 .- 1743-2812. ; 27:4, s. 286-293
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Tidskriftsartikel (refereegranskat)abstract
- The sulphur distribution ratio for ladle slags at Ovako Steel AB has been determined by calculating the sulphide capacity using the Royal Institute of Technology (KTH) model and the alumina activity via an empirical expression suggested by Ohta and Suite, and by using the well established theories for sulphur refining. A parameter study was carried out based on plant data from a previous study on desulphurisation, The effect of carbon and aluminium in the steel, the temperature of the steel, and alumina and lime in the slag on the sulphur distribution ratio was investigated, it was shown that the Al2O3/CaO ratio had the largest influence on the conditions studied, and that when it increased the sulphur distribution ratio decreased. Based on these results, new plant trials were carried out, in which the alumina content in the slag was changed. The calculated sulphur distribution ratios for these trials were found to be in good agreement with experimentally determined sulphur distribution ratios. It is concluded that the present approach can be used to optimise multicomponent ladle slags with respect to sulphur refining. I&S/1493.
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| 5. |
- Andersson, Pia, et al.
(författare)
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Oral health and nutritional status in a group of geriatric rehabilitation patients
- 2002
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Ingår i: Scandinavian Journal of Caring Sciences. - : Wiley-Blackwell. - 0283-9318 .- 1471-6712. ; 16:3, s. 311-318
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Tidskriftsartikel (refereegranskat)abstract
- The aims of this study were to evaluate the oral health status and nutritional status in a group of geriatric rehabilitation patients, and to analyse the relationship between these two parameters. Nurses at the ward performed structured assessments of oral and nutritional status using the Revised Oral Assessment Guide and the Subjective Global Assessment form in 223 newly admitted patients. Most oral health problems were found among patients who stayed longer at the hospital and were more dependent on help as compared with the healthier patients. Thirty-four per cent of the patients were either severely undernourished, at risk or suspected to be undernourished (UN). Oral health problems were more common among UN patients (p < 0.0005) compared with well-nourished patients. The most frequent oral health problem was found on teeth or dentures (48%). Problems related to the tongue and lips were also common among UN patients (56 and 44%, respectively). Oral health status was correlated (r = 0.32) to nutritional status. Problems with swallowing had the strongest association to the nutritional status (OR 6.05; 95% CI 2.41-15.18). This study demonstrated that poor oral health status was related to undernourishment.
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| 6. |
- Andersson, P, et al.
(författare)
-
Oral health and nutritional status in a group of geriatric rehabilitation patients
- 2002
-
Ingår i: Scandinavian Journal of Caring Sciences. - : Wiley. - 1471-6712 .- 0283-9318. ; 16:3, s. 311-318
-
Tidskriftsartikel (refereegranskat)abstract
- The aims of this study were to evaluate the oral health status and nutritional status in a group of geriatric rehabilitation patients, and to analyse the relationship between these two parameters. Nurses at the ward performed structured assessments of oral and nutritional status using the Revised Oral Assessment Guide and the Subjective Global Assessment form in 223 newly admitted patients. Most oral health problems were found among patients who stayed longer at the hospital and were more dependent on help as compared with the healthier patients. Thirty-four per cent of the patients were either severely undernourished, at risk or suspected to be undernourished (UN). Oral health problems were more common among UN patients (p < 0.0005) compared with well-nourished patients. The most frequent oral health problem was found on teeth or dentures (48%). Problems related to the tongue and lips were also common among UN patients (56 and 44%, respectively). Oral health status was correlated (r = 0.32) to nutritional status. Problems with swallowing had the strongest association to the nutritional status (OR 6.05; 95% CI 2.41-15.18). This study demonstrated that poor oral health status was related to undernourishment.
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| 7. |
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| 8. |
- Andersson, P, et al.
(författare)
-
Oral health problems in elderly rehabilitation patients
- 2004
-
Ingår i: International Journal of Dental Hygiene. - : Wiley. - 1601-5029 .- 1601-5037. ; 2:2, s. 70-77
-
Tidskriftsartikel (refereegranskat)abstract
- A combination of poor oral hygiene and dry mouth may be hazardous to the oral health status. However, systematic assessments in order to detect oral health problems are seldom performed in the nursing care of the elderly. The aims of this study were to investigate the occurrence of oral health problems measured using the Revised Oral Assessment Guide (ROAG) and to analyse associations between oral health problems and age, gender, living conditions, cohabitation, reason for admission, number of drugs, and functional and nutritional status. One registered nurse performed oral health assessments using ROAG in 161 newly admitted elderly patients in rehabilitation care. Oral health problems were found in 71% of the patients. Thirty per cent of these patients had between four and eight problems. Low saliva flow and problems related to lips were the most frequent oral health problems. Problems in oral health status were significantly associated with presence of respiratory diseases (problems with gums, lips, alterations on the tongue and mucous membranes), living in special accommodation (low saliva flow, problems with teeth/dentures and alterations on the tongue), being undernourished (alterations on the tongue and low saliva flow) and being a woman (low saliva flow). The highest Odds ratio (OR) was found in problems with gums in relation with prevalence of respiratory diseases (OR 8.9; confidence interval (CI) 2.8-27.8; P < 0.0005). This study indicates the importance of standardised oral health assessments in order to detect oral health problems which can otherwise be hidden when the patients are admitted to the hospital ward.
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| 9. |
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| 10. |
- Arabi, Azadeh, et al.
(författare)
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Accumulation of c-Myc and proteasomes at the nucleoli of cells containing elevated c-Myc protein levels
- 2003
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Ingår i: Journal of Cell Science. - : The Company of Biologists. - 0021-9533 .- 1477-9137. ; 116:9, s. 1707-1717
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Tidskriftsartikel (refereegranskat)abstract
- c-Myc is a predominately nuclear transcription factor that is a substrate for rapid turnover by the proteasome system. Cancer-related mutations in c-Myc lead to defects in its degradation and thereby contribute to the increase in its cellular level that is associated with the disease. Little is known about the mechanisms that target c-Myc to the proteasomes. By using a GFP fusion protein and live analysis we show that c-Myc shuttles between the nucleus and cytoplasm and thus it could be degraded in either compartment. Strikingly, at elevated levels of expression c-Myc accumulates at nucleoli in some cells, consistent with saturation of a nucleolus-associated degradation system in these cells. This idea is further supported by the observation that proteasome inhibitor treatment causes accumulation of c-Myc at the nucleoli of essentially all cells. Under these conditions c-Myc is relatively stably associated with the nucleolus, as would be expected if the nucleolus functions as a sequestration/degradation site for excess c-Myc. Furthermore, during elevated c-Myc expression or proteasome inhibition, nucleoli that are associated with c-Myc also accumulate proteasomes. c-Myc and proteasomes co-localise in intranucleolar regions distinct from the dense fibrillar component of the nucleolus. Based on these results we propose a model for c-Myc downregulation where c-Myc is sequestered at the nucleoli. Sequestration of c-Myc is accompanied by recruitment of proteasomes and may lead to subsequent degradation.
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| 11. |
- Buyanova, Irina A., et al.
(författare)
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Photoluminescence characterization of defects created in electron-irradiated silicon at elevated temperatures
- 2000
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Ingår i: Materials Science & Engineering. - 0921-5107 .- 1873-4944. ; 72:2, s. 146-149
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Tidskriftsartikel (refereegranskat)abstract
- Photoluminescence (PL) spectroscopy is employed to investigate radiative defects created in Si during electron-irradiation at elevated temperatures. The use of high temperature during electron irradiation has been found to affect considerably the defect formation process. The effect critically depends on the temperature of the irradiation as well as doping of the samples. For carbon-lean Si wafers high temperature electron irradiation stimulates the formation of extended defects, such as dislocations and precipitates. For carbon-rich Si wafers the increase of irradiation temperature up to 300°C enhances the formation of the known carbon-related defects. In addition, several new excitonic PL lines were observed after electron irradiation at T = 450°C. The dominant new PL center gives rise to a BE PL emission at 0.961 eV. The electronic structure of the 0.961 eV defect is discussed based on temperature-dependent and magneto-optical studies.
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| 12. |
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| 13. |
- Graffner-Nordberg, Malin, et al.
(författare)
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Computational predictions of binding affinities to dihydrofolate reductase: synthesis and biological evaluation of methotrexate analogues
- 2000
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 1520-4804 .- 0022-2623. ; 43:21, s. 3852-3861
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Tidskriftsartikel (refereegranskat)abstract
- The relative binding affinities to human dihydrofolate reductase of four new potential antifolates, containing ester linkages between the two aromatic systems, were estimated by free energy perturbation simulations. The ester analogue, predicted to exhibit the highest binding affinity to human dihydrofolate reductase, and a reference ester (more structurally related to methotrexate) were synthesized. As deduced from the measured IC(50) values, the calculated ranking of the ligands was correct although a greater difference in affinity was indicated by the experimental measurements. Among the new antifolates the most potent inhibitor exhibited a similar pharmacokinetic profile to methotrexate but lacked activity in a complex antiarthritic model in rat in vivo.
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| 14. |
- Graffner-Nordberg, Malin, et al.
(författare)
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Design, Synthesis, Computational Prediction and Biological Evaluation of Ester Soft Drugs as Inhibitors of Dihydrofolate Reductase from Pneumocystis Carinii
- 2001
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 44:15, s. 2391-2402
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Tidskriftsartikel (refereegranskat)abstract
- A series of lipophilic soft drugs structurally related to the nonclassical dihydrofolate reductase (DHFR) inhibitors trimetrexate and piritrexim have been designed, synthesized, and evaluated in DHFR assays, with special emphasis on the inhibition of P. carinii DHFR. The best inhibitors, encompassing an ester bond in the bridge connecting the two aromatic systems, were approximately 10 times less potent than trimetrexate and piritrexim. The metabolites were designed to be poor inhibitors. Furthermore, molecular dynamics simulations of three ligands in complex with DHFR from Pneumocystis carinii and from the human enzyme were conducted in order to better understand the factors determining the selectivity. A correct ranking of the relative inhibition of DHFR was achieved utilizing the linear interaction energy method. The soft drugs are intended for local administration. One representative ester was selected for a pharmacokinetic study in rats where it was found to undergo fast metabolic degradation to the predicted inactive metabolites.
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| 15. |
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| 16. |
- Hallberg, Pär, et al.
(författare)
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Gender-specific association between preproendothelin-1 genotype and reduction of systolic blood pressure during antihypertensive treatment : results from the Swedish Irbesartan Left Ventricular Hypertrophy Investigation versus Atenolol (SILVHIA)
- 2004
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Ingår i: Clinical Cardiology. - : Wiley. - 0160-9289 .- 1932-8737. ; 27:5, s. 287-290
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Studies suggest that endothelin-1 contributes to the pathogenesis of hypertension. A G5665T gene polymorphism of preproendothelin-1 has been shown to be associated with higher blood pressure in overweight patients. No study has yet determined the effect of this polymorphism on the change in blood pressure during antihypertensive treatment.HYPOTHESIS:This study aimed to determine this effect in hypertensive patients with left ventricular (LV) hypertrophy during antihypertensive treatment with either irbesartan or atenolol.METHODS: We determined the preproendothelin-1 genotype using minisequencing in 102 patients with essential hypertension and LV hypertrophy verified by echocardiography, randomized in a double-blind fashion to treatment with either the AT1-receptor antagonist irbesartan or the beta1-adrenoceptor antagonist atenolol.RESULTS:The change in systolic blood pressure (SBP) after 12 weeks of treatment was related to the preproendothelin-1 genotype in men; after adjustment for potential covariates (age, blood pressure, and LV mass index at study entry, dose of irbesartan/atenolol, and type of treatment), those carrying the T-allele responded on average with a more than two-fold greater reduction than those with the G/G genotype (-21.9 mmHg [13.9] vs. -8.9 [2.3], p = 0.007). No significant differences in blood pressure change between G/G and carriers of the T-allele were seen among women.CONCLUSIONS:Our finding suggests a gender-specific relationship between the G5665T preproendothelin-1 polymorphism and change in SBP in response to antihypertensive treatment with irbesartan or atenolol, suggesting the endothelin pathway to be a common mechanism included in the hypertensive action of the drugs.
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| 17. |
- Hermansson, J., et al.
(författare)
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Complexes of the self-interstitial with oxygen in irradiated silicon : A new assignment of the 936 cm-1 band
- 2001
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 302-303, s. 188-192
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Three vibrational infrared absorption bands at about 936, 944 and 956 cm-1 appear commonly in spectra of Czochralski-grown silicon irradiated at low temperatures. All three bands have earlier been assigned to local vibrational modes related to oxygen in the complex of the silicon and the oxygen interstitials (IOi). However, it is shown that such an assignment of the 936 cm-1 band clearly is inconsistent with many facts and observations and that the band is most likely due to oxygen vibrations in the Si interstitial pair and interstitial oxygen complex, I2Oi. © 2001 Published by Elsevier Science B.V.
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| 18. |
- Karlsson, J, et al.
(författare)
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Beta1-adrenergic receptor gene polymorphisms and response to beta1-adrenergic receptor blockade in patients with essential hypertension
- 2004
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Ingår i: Clinical Cardiology. - 0160-9289 .- 1932-8737. ; 27:6 SUPPL. 3, s. 347-350
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies suggest that the Ser49Gly and Arg389Gly polymorphisms in the β1-adrenergic receptor might be of functional importance for the cardiovascular system. Both have been associated with altered receptor activity in vitro, and with hypertension and cardiac failure in vivo. Hypothesis: The aim of this study was to test whether these polymorphisms were associated with the change in heart rate or blood pressure in patients with essential hypertension and left ventricular (LV) hypertrophy treated with the β1-adrenergic receptor blocker atenolol. Methods: Blood pressure and heart rate were measured in 101 hypertensive patients with echocardiographically verified LV hypertrophy, randomized in a double-blind study to treatment with either the β1-adrenergic receptor blocker atenolol or the angiotensin II type I receptor antagonist irbesartan. Changes in blood pressure and heart rate were evaluated after 12 weeks. Beta1-adrenergic receptor genotyping was performed using polymerase chain reaction and restriction fragment length polymorphism. Results: We found no significant associations between the changes in the measured variables and either of the two polymorphisms. However, carriers of the 49Gly allele showed a tendency toward a greater reduction in heart rate compared with patients with the Ser/Ser49 genotype (p = 0.06). Conclusions: The Ser49Gly and Arg389Gly β1-adrenergic receptor polymorphisms do not seem to exert a major effect on the changes in heart rate and blood pressure during 12 weeks of treatment with atenolol in patients with essential hypertension and LV hypertrophy.
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| 19. |
- Karlsson, Julia, et al.
(författare)
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Beta1-adrenergic receptor gene polymorphisms and response to beta1-adrenergic receptor blockade in patients with essential hypertension
- 2004
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Ingår i: Clinical Cardiology. - : Wiley. - 0160-9289 .- 1932-8737. ; 27:6, s. 347-350
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Studies suggest that the Ser49Gly and Arg389Gly polymorphisms in the beta1-adrenergic receptor might be of functional importance for the cardiovascular system. Both have been associated with altered receptor activity in vitro, and with hypertension and cardiac failure in vivo. HYPOTHESIS: The aim of this study was to test whether these polymorphisms were associated with the change in heart rate or blood pressure in patients with essential hypertension and left ventricular (LV) hypertrophy treated with the beta1-adrenergic receptor blocker atenolol. METHODS: Blood pressure and heart rate were measured in 101 hypertensive patients with echocardiographically verified LV hypertrophy, randomized in a double-blind study to treatment with either the beta1-adrenergic receptor blocker atenolol or the angiotensin II type I receptor antagonist irbesartan. Changes in blood pressure and heart rate were evaluated after 12 weeks. Beta1-adrenergic receptor genotyping was performed using polymerase chain reaction and restriction fragment length polymorphism. RESULTS: We found no significant associations between the changes in the measured variables and either of the two polymorphisms. However, carriers of the 49Gly allele showed a tendency toward a greater reduction in heart rate compared with patients with the Ser/Ser49 genotype (p = 0.06). CONCLUSIONS: The Ser49Gly and Arg389Gly beta1-adrenergic receptor polymorphisms do not seem to exert a major effect on the changes in heart rate and blood pressure during 12 weeks of treatment with atenolol in patients with essential hypertension and LV hypertrophy.
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| 20. |
- Lindstrom, J.L., et al.
(författare)
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Defect engineering in Czochralski silicon by electron irradiation at different temperatures
- 2002
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - 0168-583X .- 1872-9584. ; 186:1-4, s. 121-125
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Tidskriftsartikel (refereegranskat)abstract
- Infrared absorption studies of defect formation in Czochralski silicon irradiated with fast electrons in a wide range of temperatures (80-900 K) have been performed. The samples with different contents of oxygen (16O,18O) and carbon (12C,13C) isotopes were investigated. The main defect reactions are found to depend strongly on irradiation temperature and dose, as well as on impurity content and pre-history of the samples. Some new radiation-induced defects are revealed after irradiation at elevated temperatures as well as after a two-step (hot+room-temperature (RT)) irradiation. © 2002 Elsevier Science B.V. All rights reserved.
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| 21. |
- Lindstrom, J.L., et al.
(författare)
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Interaction between self-interstitials and the oxygen dimer in silicon
- 2001
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 308-310, s. 284-289
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Tidskriftsartikel (refereegranskat)abstract
- Interactions between the oxygen dimer (O2i) and silicon self-interstitials (I) and vacancies (V) have been studied in Czochralski-grown silicon (Cz-Si) crystals using infrared absorption and deep level transient spectroscopies. The focus in this report is on reactions of O2i with I. The first step in this interaction is found to be the formation of a self-interstitial-dioxygen centre (IO2i) with oxygen-related local vibrational mode (LVM) bands at 922 and 1037 cm-1. During the second formation step, another centre, I2O2i, with LVM bands at 918 and 1034 cm-1 is suggested to appear. A Si-related band at about 545 cm-1 is also assigned to both the IO2i and I2O2i centres. The IO2i centre is found to be electrically active with an acceptor level at Ec - 0.11 eV. The both defects, IO2i and I2O2i, are stable at room temperature and anneal out at about 400 and 550 K, respectively. © 2001 Elsevier Science B.V. All rights reserved.
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| 22. |
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| 23. |
- Lindström, Lennart, et al.
(författare)
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The VO2* defect in silicon
- 2003
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Ingår i: Physica. B, Condensed matter. - : Elsevier BV. - 0921-4526 .- 1873-2135. ; 340-342, s. 509-513
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The vacancy-dioxygen complex (VO2) is one of the main defects formed in irradiated Cz-Si crystals upon annealing (or irradiation) in the temperature range 300-400°C. In this defect two oxygen atoms share a vacancy, each bonded to two silicon neighbors. Independent vibrations of these O atoms give rise to one infrared absorption band at 895.5 cm-1 at 10 K. We report on an experimentally discovered bistability of this defect. We suggest an alternative configuration, VO2*, where only one O atom is inside the vacancy while the second O atom is in a backbond position. Two vibrational bands, at 928.4 and 1003.8 cm-1 (positions at 15 K), are assigned to this configuration. © 2003 Elsevier B.V. All rights reserved.
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| 24. |
- Mason, M. G., et al.
(författare)
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The heme domain of cellobiose oxidoreductase : a one-electron reducing system
- 2003
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Ingår i: Biochimica et Biophysica Acta - Bioenergetics. - : Elsevier BV. - 0005-2728 .- 1879-2650. ; 1604:1, s. 47-54
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Tidskriftsartikel (refereegranskat)abstract
- Phanerochaete chrysosporium cellobiose oxidoreductase (CBOR) comprises two redox domains, one containing flavin adenine dinucleotide (FAD) and the other protoheme. It reduces both two-electron acceptors, including molecular oxygen, and one-electron acceptors, including transition metal complexes and cytochrome c. If the latter reacts with the flavin, the reduced heme b acts merely as a redox buffer, but if with the b heme, enzyme action involves a true electron transfer chain. Intact CBOR fully reduced with cellobiose, CBOR partially reduced by ascorbate, and isolated ascorbate-reduced heme domain, all transfer electrons at similar rates to cytochrome c. Reduction of cationic one-electron acceptors via the heme group supports an electron transfer chain model. Analogous reactions with natural one-electron acceptors can promote Fenton chemistry, which may explain evolutionary retention of the heme domain and the enzyme's unique character among secreted sugar dehydrogenases.
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| 25. |
- Murin, L.I., et al.
(författare)
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Early stages of oxygen clustering in hydrogenated Cz-Si : IR absorption studies
- 2001
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 302-303, s. 180-187
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The formation kinetics of small oxygen clusters in hydrogenated Si has been studied by means of infrared absorption measurements. Hydrogen was introduced into the crystals by in-diffusion from H2 gas at 1200-1300°C. The samples were heated at temperatures in the range of 280-370°C for different durations. At initial stages of heat-treatment, enormous generation rates of the oxygen dimer have been observed in hydrogenated samples. This indicates highly enhanced diffusion of the interstitial oxygen atoms. The maximum achievable concentration of the dimers is found to be limited by their dissociation rate even at temperatures of about 300°C, while in as-grown crystals the capture processes are known to be dominant in this temperature region. An explanation of this phenomenon is presented. © 2001 Published by Elsevier Science B.V.
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| 26. |
- Nilsson, P, et al.
(författare)
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A new highly asymmetric chelation-controlled heck arylation
- 2003
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Ingår i: Journal of the American Chemical Society. - Uppsala Univ, Uppsala Biomed Ctr, Dept Organ Pharmaceut Chem, SE-75123 Uppsala, Sweden. : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 125, s. 3430-
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Tidskriftsartikel (refereegranskat)
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| 27. |
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| 28. |
- Nilsson, P, et al.
(författare)
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Highly regioselective, sequential, and multiple palladium-catalyzed arylations of vinyl ethers carrying a coordinating auxiliary : An example of a Heck triarylation process
- 2001
-
Ingår i: Journal of the American Chemical Society. - Uppsala Univ, Uppsala Biomed Ctr, Dept Organ Pharmaceut Chem, SE-75123 Uppsala, Sweden. : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 123:34, s. 8217-8225
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Tidskriftsartikel (refereegranskat)abstract
- This article describes the development of new auxiliary-accelerated Heck multiarylations by intramolecular presentation of the oxidative addition complex. The introduction of a specific, palladium-coordinating dimethylamino group allows for the desired chelation-accelerated and chelation-controlled triand diarylation reactions. We report (a) the first example of a Heck triarylation process, (b) highly selective palladium-catalyzed diarylations of alkyl vinyl ethers, and (c) a very rapid two-phase protocol for the microwave-assisted hydrolysis of amino-substituted, arylated vinyl ethers constituting an entry to diarylated ethanals and substituted desoxybenzoins. X-ray structures and product patterns support the suggested substrate-controlled Heck reaction pathway. The catalyst-directing alkyl dimethylamino functionality was rapidly (1-2 min) and efficiently released by microwave hydrolysis after Heck multiarylation reactions. The liberated aromatic carbonyl compounds were thereafter isolated and fully characterized.
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| 29. |
- Nilsson, P, et al.
(författare)
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Microwave-assisted enantioselective Heck reactions : Expediting high reaction speed and preparative convenience
- 2002
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Ingår i: Synthesis (Stuttgart). - Univ Uppsala, Ctr Biomed, Dept Organ Pharmaceut Chem, S-75123 Uppsala, Sweden.. - 0039-7881 .- 1437-210X. ; :11, s. 1611-1614
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Tidskriftsartikel (refereegranskat)abstract
- Palladium-catalyzed asymmetric Heck reactions have been per-formed using high temperature conditions with the aid of controlled microwave dielectric heating. Significant enantioselectivities of up to 92% ee were obtained under non-inert conditions utilizing the previously reported thermostable palladium-phosphineoxazoline catalytic system. With microwave irradiation. reaction times of hours instead of days were obtained. Enantiomeric purities and conversions were found to be strongly dependent on both the choice of the aryl triflate, the reaction temperature, the solvent and the base. Examples of asymmetric arylations of electron-rich as well as neutral cyclic alkenes are presented.
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| 30. |
- Rotsaert, F. A. J., et al.
(författare)
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Biophysical and structural analysis of a novel heme b iron ligation in the flavocytochrome cellobiose dehydrogenase
- 2003
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 278:35, s. 33224-33231
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Tidskriftsartikel (refereegranskat)abstract
- The fungal extracellular flavocytochrome cellobiose dehydrogenase (CDH) participates in lignocellulose degradation. The enzyme has a cytochrome domain connected to a flavin-binding domain by a peptide linker. The cytochrome domain contains a 6-coordinate low spin b-type heme with unusual iron ligands and coordination geometry. Wild type CDH is only the second example of a b-type heme with Met-His ligation, and it is the first example of a Met-His ligation of heme b where the ligands are arranged in a nearly perpendicular orientation. To investigate the ligation further, Met(65) was replaced with a histidine to create a bis-histidyl ligated iron typical of b-type cytochromes. The variant is expressed as a stable 90-kDa protein that retains the flavin domain catalytic reactivity. However, the ability of the mutant to reduce external one-electron acceptors such as cytochrome c is impaired. Electrochemical measurements demonstrate a decrease in the redox midpoint potential of the heme by 210 mV. In contrast to the wild type enzyme, the ferric state of the protoheme displays a mixed low spin/high spin state at room temperature and low spin character at 90 K, as determined by resonance Raman spectroscopy. The wild type cytochrome does not bind CO, but the ferrous state of the variant forms a CO complex, although the association rate is very low. The crystal structure of the M65H cytochrome domain has been determined at 1.9 Angstrom resolution. The variant structure confirms a bis-histidyl ligation but reveals unusual features. As for the wild type enzyme, the ligands have a nearly perpendicular arrangement. Furthermore, the iron is bound by imidazole N-delta1 and N-epsilon2 nitrogen atoms, rather than the typical N-epsilon2/N-epsilon2 coordination encountered in bis-histidyl ligated heme proteins. To our knowledge, this is the first example of a bis-histidyl N-delta1/N-epsilon2-coordinated protoporphyrin IX iron.
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| 31. |
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| 32. |
- Vallin, K S A, et al.
(författare)
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A new regioselective Heck vinylation with enamides. Synthesis and investigation of fluorous-tagged bidentate ligands for fast separation
- 2003
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Ingår i: Journal of Organic Chemistry. - Uppsala Univ, BMC, Dept Organ Pharmaceut Chem, SE-75123 Uppsala, Sweden. Univ Pittsburgh, Dept Chem, Pittsburgh, PA 15260 USA. : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 68:17, s. 6639-6645
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Tidskriftsartikel (refereegranskat)abstract
- Internal ligand-controlled Heck vinylations of enamides were performed with high regioselectivity and delivered moderate to good yields of dienamides. Controlled heating by microwave irradiation accelerated the palladium-catalyzed reactions, and full conversions were achieved after reaction times of only 15-30 min. New bidentate fluorous-tagged 1,3-bis(diphenylphosphino)propane ligands (F-dppp's) were synthesized and examined. The cationic vinylations of the enamides with F-dppp ligands rendered essentially the same alpha-selectivity and catalytic activity as in those vinylations where nonfluorous ligands were employed. After reaction, the fluorous-tagged ligand material was easily removed by convenient solid fluorous phase separation. The high selectivity, simplicity, and generality of the experimental procedure should make this approach to 2-acylamino-1,3-butadienes attractive.
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| 33. |
- Vallin, K S A, et al.
(författare)
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High-speed Heck reactions in ionic liquid with controlled microwave heating
- 2002
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Ingår i: Journal of Organic Chemistry. - Uppsala Univ, BMC, Dept Organ Pharmaceut Chem, SE-75123 Uppsala, Sweden. : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 67:17, s. 6243-6246
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Tidskriftsartikel (refereegranskat)abstract
- Palladium-catalyzed Heck arylations in the polar and robust ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF(6)), have for the first time been accomplished under microwave irradiation. The couplings were efficiently performed in sealed tubes within 5-45 min of heating. Without significant reductions in yield, a phosphine-free ionic catalyst phase could be recycled in five successive 20 min reactions at 180 degreesC. The product was easily removed from the reaction medium by distillation.
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