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| 2. |
- Strömberg, Dan, 1959, et al.
(författare)
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Relativistic calculations on some mercury sulphide molecules
- 1991
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Ingår i: Water Air and Soil Poll. - 0049-6979. ; 56:1, s. 681-695
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Tidskriftsartikel (refereegranskat)abstract
- Relativistic quantum calculations at the CASSCF- and CCI-levels were performed on the Hg(SH)2, HgSH and HgS molecules. The relativistic effects were taken into account by a relativistic effective core potential method. Dissociation energies and optimal geometries were calculated for these three molecules, which are plausible atmospheric Hg compounds. The Hg(SH)2 and HgSH molecules (in the gaseous phase) have never been studied before, neither experimentally nor theoretically, i.e. the existence of these molecules are uncertain. The theoretical dissociation energies, De's, of Hg(SH)2 and HgSH (at the CCI-level) were 59 kcal·mol–1 and 3 kcal·mol–1, respectively, indicating that Hg(SH)2 could be stable in the atmosphere but probably not HgSH. The theoretical De of HgS differs very much from the experimental one, but the reason for this is not clear. The Hg-S distances for Hg(SH)2, HgSH and HgS were found to be 2.38, 2.63 and 2.30 Å, respectively. The Hg-S-H angle in Hg(SH)2 was optimized to 93°. The excitation energies of Hg(SH)2, Hg(SH)2(H2O)4 and (HSHg)2S were calculated in order to see whether these species can absorb photons with wavelengths longer than 290 nm (the sunlight limit) and subsequently be photolyzed. The Hg(SH)2(H2O)4 complex is intended as a model for Hg(SH)2(aq). Photoreduction of Hg-sulfide species in sea water, yielding Hg0, could be an important source of Hg in the atmosphere. Excitation energies lower than the sunlight limit (4.3 eV290 nm) were found for Hg(SH)2 and Hg(SH)2(H2O)4, although the lowest spin and dipole allowed excitations probably lie slightly (0.2 to 0.3 eV) above this limit. Therefore a photodecomposition of Hg(SH)2(g) and Hg(SH)2(aq) by sunlight seems likely to occur.
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| 4. |
- Akesson, AA, et al.
(författare)
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Tubular and glomerular kidney effects in Swedish women with low environmental cadmium exposure
- 2005
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Ingår i: Environmental Health Perspectives. - : Environmental Health Perspectives. - 1552-9924 .- 0091-6765. ; 113:11, s. 1627-1631
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Tidskriftsartikel (refereegranskat)abstract
- Cadmium is a well-known nephrotoxic agent in food and tobacco, but the exposure level that is critical for kidney effects in the general population is not defined. Within a population-based women's health survey in southern Sweden (Women's Health in the Lund Area, WHILA), we investigated cadmium exposure in relation to tubular and glomerular function, from 1999 through early 2000 in 820 women (71% participation rate) 53-64 years of age. Multiple linear regression showed cadmium in blood (median, 0.38 mu g/L) and urine (0.52 mu g/L; density adjusted = 0.67 mu g/g creatinine) to be significantly associated with effects on renal tubules (as indicated by increased levels of human complex-forming protein and N-acetyl-beta-D-glucosaminidase in urine), after adjusting for age, body mass index, blood lead, diabetes, hypertension, and regular use of nephrotoxic drugs. The associations remained significant even at the low exposure in women who had never smoked. We also found associations with markers of glomerular effects: glomerular filtration rate and creatinine clearance. Significant effects were seen already at a mean urinary cadmium level of 0.6 mu g/L (0.8 mu g/g creatinine). Cadmium potentiated diabetes-induced effects on kidney. In conclusion, tubular renal effects occurred at lower cadmium levels than previously demonstrated, and more important, glomerular effects were also observed. Although the effects were small, they may represent early signs of adverse effects, affecting large segments of the population. Subjects with diabetes seem to be at increased risk.
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| 5. |
- Akhtar, Sultan, et al.
(författare)
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Visualization of functionalization of nano-particles and graphene in the TEM
- 2010
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Ingår i: Advanced Materials Workshop 2010.
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Konferensbidrag (refereegranskat)abstract
- Recently, the activity on functionalized nano-objects has strongly increased. Yet, there are, to our knowledge no techniques available that visualize the attachment of molecules to nano-entities such as nanoparticles and graphene. In this work, we show a methodology to analyse the attachment of molecules to nanoparticles and graphene. The difficulty of such transmission electron microscopy (TEM) characterization consists in the high beam sensitivity of these nanoobjects. We employed a high resolution- as well as diffraction contrast-imaging methods to characterize graphene. First, we have developed a method to measure the thickness of free-standing graphene-like layers. The refinement of these imaging techniques enabled the imaging of functionalized C60 (fullerene) on top of a few-layer graphene flake by TEM. We also developed a methodology to visualize the attachment of functionalized gold and magnetic nanoparticles (different sizes) to nonstained and unlabeled single strand DNA-coils. This technique can be used to understand the interaction of a large variety of functionalized nanoparticles with their solution environment and/or macromolecular structures for their large applications.
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| 6. |
- Albin, Maria, et al.
(författare)
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Cytogenetic and morphologic subgroups of myelodysplastic syndromes in relation to occupational and hobby exposures.
- 2003
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Ingår i: Scandinavian Journal of Work, Environment and Health. - 0355-3140. ; 29:5, s. 378-387
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: This study investigated the association between occupational and hobby exposure and the risk of myelodysplastic syndromes (MDS) while focusing on differential patterns of clonal chromosome aberrations and morphologic subgroups. METHODS: A case-referent study was conducted with 330 MDS patients investigated cytogenetically in 1976-1993 (cases) and matched referents. Telephone interviews with either the person or a next-of-kin were used. The participation rate of the cases and referents was 85% and 60%, respectively. Information was obtained from the next-of-kin more often for the cases (88%) than for the referents (26%). Occupational hygienists assessed the exposure using interview data on worktasks and hobbies. Associations with disease risk were evaluated for 10 exposures with a logistic regression analysis. RESULTS: The investigated exposures were generally not associated with cytogenetically abnormal MDS. Effect estimates for specific cytogenetic or morphologic subgroups were generally imprecise. Occupational exposure to extremely low-frequency magnetic fields (EMF) was associated with MDS with a normal karyotype [odds ratio (OR) 2.0, 95% confidence interval (95% CI) 1.0-4.0]. The exposure-response association was consistent for intensity but inconclusive for duration. A decreased risk was observed for MDS, irrespective of karyotypic pattern, among farmers and farmhands (OR 0.53, 95% CI 0.35-0.81). CONCLUSIONS: Cytogenetically abnormal MDS was generally not associated with occupational or hobby exposure to known or suspected genotoxic agents. However, exposure prevalences and intensities were low for several agents. An association was suggested between occupational exposure to EMF and MDS with a normal karyotype. Biases due to differential information quality and selective participation cannot be ruled out.
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| 7. |
- Albin, Maria, et al.
(författare)
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Retention patterns of asbestos fibres in lung tissue among asbestos cement workers
- 1994
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Ingår i: Occupational and Environmental Medicine. - 1470-7926. ; 51:3, s. 205-211
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Tidskriftsartikel (refereegranskat)abstract
- Retention patterns in lung tissue (determined by transmission electron microscopy and energy dispersive spectrometry) of chrysotile, tremolite, and crocidolite fibres were analysed in 69 dead asbestos cement workers and 96 referents. There was an accumulation of tremolite with time of employment. Among workers who died within three years of the end of exposure, the 13 with high tremolite concentrations had a significantly longer duration of exposure than seven in a low to intermediate category (medians 32 v 20 years; p = 0.018, one sided). Crocidolite showed similar patterns of accumulation. In workers who died more than three years after the end of exposure, there were no correlations between concentrations of amphibole fibres and time between the end of exposure and death. Chrysotile concentrations among workers who died shortly after the end of exposure were higher than among the referents (median difference in concentrations 13 million fibres (f)/g dry weight; p = 0.033, one sided). No quantitative differences in exposure (duration or intensity) could be shown between workers with high and low to intermediate concentrations. Interestingly, all seven workers who had had a high intensity at the end of exposure (> 2.5 f/ml), had low to intermediate chrysotile concentrations at death, whereas those with low exposure were evenly distributed (31 subjects in both concentration categories); hence, there was a dependence between last intensity of exposure and chrysotile concentration (p = 0.014). Among 14 workers with a high average intensity of exposure, both those (n = 5) with high tissue concentrations of chrysotile and those (n = 10) with high tissue concentrations of tremolite fibres had more pronounced fibrosis than those with low to intermediate concentrations (median fibrosis grades for chrysotile: 2 v 1, p = 0.021; for tremolite: 2 v 0.5, p = 0.012). Additionally, workers who died shortly after the end of exposure with high concentrations of chrysotile and crocidolite had smoked more than those with low intermediate concentrations (medians for chrysotile 35 v 15 pack-years, p = 0.030; for crocidolite 37 v 15 pack-years, p = 0.012). The present data indicate that chrysotile has a relatively rapid turnover in human lungs, whereas the amphiboles, tremolite and crocidolite, have a slower turnover. Further, chrysotile retention may be dependent on dose rate. Chrysotile and crocidolite deposition and retention may be increased by tobacco smoking; chrysotile and tremolite by fibrosis.
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| 8. |
- Almquist-Tangen, Gerd, et al.
(författare)
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Influence of neighbourhood purchasing power on breastfeeding at four months of age : a Swedish population-based cohort study
- 2013
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Ingår i: BMC Public Health. - London : BioMed Central. - 1471-2458. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Parental socioeconomic status (SES) is an important determinant in child health, influencing beneficial factors such as breastfeeding. A better understanding of the influence of neighbourhood-level SES measures, relating to spatial determinants, might lead to targeted actions to promote breastfeeding during infancy.METHODS: A cross-sectional study analysis the association between breastfeeding at four months of age and neighbourhood purchasing power, taking account of individual-level variables including maternal age, smoking and parental level of education. Data were obtained from a prospective population- based cohort study recruited from birth in 2007-2008 in the Halland region, southwestern Sweden. Questionnaire data on the individual-level variables and the outcome variable of breastfeeding at four months (yes/no) were used (n=2,407). Each mother was geo-coded with respect to her residential parish (there are 61 parishes in the region) and then stratified by parish-level household purchasing power. It emerged that four neighbourhood characteristics were reasonable to use, viz. <10%, 10-19%, 20-29% and ≥ 30% of the resident families with low purchasing power.RESULTS: The proportion of mothers not breastfeeding at four months of age showed a highly significant trend across the neighbourhood strata (p=0.00004): from 16.3% (< 10% with low purchasing power) to 29.4% (≥ 30% with low purchasing power), yielding an OR of 2.24 (95% confidence interval: 1.45-3.16). After adjusting for the individual-level variables, the corresponding OR=1.63 (1.07-2.56) was significant and the trend across the strata was still evident (p=0.05). A multi-level analysis estimated that, in the neighbourhoods with ≥ 30% of the families with low purchasing power, 20% more mothers than expected, taking account of the individual-level factors, reported no breastfeeding at four months of age (≥ 95% posterior probability of an elevated observed-to-expected ratio).CONCLUSION: The neighbourhood purchasing power provided a spatial determinant of low numbers of mothers breastfeeding at four months of age, which could be relevant to consider for targeted actions. The elevated observed-to-expected ratio in the neighbourhoods with the lowest purchasing power points toward a possible contextual influence. © 2013 Almquist-Tangen et al.; licensee BioMed Central Ltd.
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| 9. |
- Axelson, Ulf, et al.
(författare)
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Borrow cheap, buy high? : the determinants of leverage and pricing in buyouts
- 2013
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Ingår i: Journal of Finance. - : Wiley: No OnlineOpen. - 1540-6261 .- 0022-1082. ; 68:6, s. 2223-2267
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Tidskriftsartikel (refereegranskat)abstract
- Private equity funds pay particular attention to capital structure when executing leveraged buyouts, creating an interesting setting for examining capital structure theories. Using a large, international sample of buyouts from 1980 to 2008, we find that buyout leverage is unrelated to the cross-sectional factors, suggested by traditional capital structure theories, that drive public firm leverage. Instead, variation in economy-wide credit conditions is the main determinant of leverage in buyouts. Higher deal leverage is associated with higher transaction prices and lower buyout fund returns, suggesting that acquirers overpay when access to credit is easier.
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