| 1. |
- Klug, Stefanie J, et al.
(författare)
-
TP53 codon 72 polymorphism and cervical cancer : a pooled analysis of individual data from 49 studies
- 2009
-
Ingår i: The Lancet Oncology. - 1470-2045 .- 1474-5488. ; 10:8, s. 772-784
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cervical cancer is caused primarily by human papillomaviruses (HPV). The polymorphism rs1042522 at codon 72 of the TP53 tumour-suppressor gene has been investigated as a genetic cofactor. More than 80 studies were done between 1998 and 2006, after it was initially reported that women who are homozygous for the arginine allele had a risk for cervical cancer seven times higher than women who were heterozygous for the allele. However, results have been inconsistent. Here we analyse pooled data from 49 studies to determine whether there is an association between TP53 codon 72 polymorphism and cervical cancer. METHODS: Individual data on 7946 cases and 7888 controls from 49 different studies worldwide were reanalysed. Odds ratios (OR) were estimated using logistic regression, stratifying by study and ethnic origin. Subgroup analyses were done for infection with HPV, ethnic origin, Hardy-Weinberg equilibrium, study quality, and the material used to determine TP53 genotype. FINDINGS: The pooled estimates (OR) for invasive cervical cancer were 1.22 (95% CI 1.08-1.39) for arginine homozygotes compared with heterozygotes, and 1.13 (0.94-1.35) for arginine homozygotes versus proline homozygotes. Subgroup analyses showed significant excess risks only in studies where controls were not in Hardy-Weinberg equilibrium (1.71 [1.21-2.42] for arginine homozygotes compared with heterozygotes), in non-epidemiological studies (1.35 [1.15-1.58] for arginine homozygotes compared with heterozygotes), and in studies where TP53 genotype was determined from tumour tissue (1.39 [1.13-1.73] for arginine homozygotes compared with heterozygotes). Null results were noted in studies with sound epidemiological design and conduct (1.06 [0.87-1.29] for arginine homozygotes compared with heterozygotes), and studies in which TP53 genotype was determined from white blood cells (1.06 [0.87-1.29] for arginine homozygotes compared with heterozygotes). INTERPRETATION: Subgroup analyses indicated that excess risks were most likely not due to clinical or biological factors, but to errors in study methods. No association was found between cervical cancer and TP53 codon 72 polymorphism when the analysis was restricted to methodologically sound studies.
|
|
| 2. |
- Davidsson, Kent, 1967, et al.
(författare)
-
Potassium, chlorine, and sulfur in ash, particles, deposits, and corrosion during wood combustion in a circulating fluidized-bed boiler
- 2007
-
Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 21:1, s. 71-81
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of the addition of chlorine and/or sulfur to the fuel on fly ash composition, deposit formation, and superheater corrosion has been studied during biomass combustion in a circulating fluidized-bed boiler. The chlorine (HCl (aq)) and sulfur (SO2 (g)) were added in proportions of relevance for the potassium chemistry. The composition of the bottom and the fly ashes was analyzed. Gas and particle measurements were performed downstream of the cyclone before the convection pass and the flue gas composition was recorded in the stack with a series of standard instruments and an FTIR analyzer. At the position downstream of the cyclone, a deposit probe was situated, simulating a superheater tube. Deposits on the probe and initial corrosion were examined. It is concluded that addition of sulfur and chlorine increases the formation of submicron particles leading to deposition of potassium sulfate and chloride. The results compare well with earlier work based on laboratory-scale experiments concerning effects of chlorine and sulfur on potassium chemistry.
|
|
| 3. |
|
|
| 4. |
- Johansson, Emma, et al.
(författare)
-
On the Formation of Discoidal versus Threadlike Micelles in Dilute Aqueous Surfactant/Lipid Systems
- 2008
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 24:5, s. 1731-1739
-
Tidskriftsartikel (refereegranskat)abstract
- In a recent study, we showed that the surfactant 1,2-distearoyl-sn-glycero-3-phosphatidylethanolamine-N-[methoxy(polyethylene glycol)-2000 (DSPE-PEG2000) induced mixed micelles of either threadlike or discoidal shape when mixed with different types of lipids. In this study, we have exchanged the PEG−lipid for the more conventional surfactants octaethylene glycol monododecyl ether (C12E8), hexadecyltrimethylammonium bromide (CTAB), and sodium dodecyl sulfate (SDS). Cryo-TEM investigations show that also these surfactants are able to induce the formation of long-lived discoidal micelles. Generally, the preference for either discoidal or threadlike micelles can be tuned by the choice of lipids and environmental conditions in much the same way as observed for the lipid/PEG−lipid system. Our investigation showed, furthermore, that the choice of surfactant may influence the type of mixed micelles formed. It is argued that the formation of discoidal rather than threadlike micelles may be rationalized as an effect of increasing bending rigidity. Our detailed theoretical model calculations show that the bending rigidity becomes significantly raised for aggregates formed by an ionic rather than a nonionic surfactant.
|
|
| 5. |
- Svane, Maria, 1957, et al.
(författare)
-
Cesium as a tracer for alkali processes in a circulating fluidized bed reactor
- 2006
-
Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 20:3, s. 979-985
-
Tidskriftsartikel (refereegranskat)abstract
- Addition of cesium salt has been used to study the removal rate, transport, and fate of alkali components during combustion of a mixture of wood chips and pellets in a 12-MW circulating fluidized bed (CFB) reactor. The alkali concentration in the flue gas was monitored with a recently developed aerosol mass spectrometer to provide on-line measurements of alkali-containing submicron particles. Cs2CO3 was fed with the fuel during a 5.5-h period, and the Cs concentration in the flue gas and in ash samples was followed for 70 h. Cesium addition resulted in a 1000-fold increase in Cs concentrations, followed by a slow decay of the concentrations during the following days. Cs was concluded to bind strongly to the fluidized bed material and to be removed with the bed ash or by slow release to the gas phase. The apparent rate coefficient for Cs removal from the bed was approximately 0.03 h(-1). After 70 h, 33 +/- 10% of the added cesium had been removed with the bottom ash, 7 +/- 5% with secondary cyclone ash, and 45 +/- 10% with the bag-house filter ash. About 15% of the Cs remained in the facility at this time, either bound to the fluidized bed material or as deposits on surfaces. Cesium compounds released from the bed participate in the formation of new particles that are efficiently collected by the bag-house filters. A minor Cs fraction also condenses on fly ash particles that are removed by the secondary cyclone. The study shows that the results of cesium addition can be followed in detail under typical operation conditions, and the potential of the tracer method for studies of transformations and fate of alkali compounds in commercial scale boilers is discussed.
|
|
| 6. |
- Svane, Maria, 1957, et al.
(författare)
-
On-line alkali analysis of individual aerosol particles in urban air
- 2005
-
Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 39:36, s. 6919-6930
-
Tidskriftsartikel (refereegranskat)abstract
- On-line measurements of individual alkali-containing submicron particles in ambient air have been performed at two urban sites in Goteborg, on the west coast of Sweden. Results obtained with a recently developed particle beam mass spectrometer are presented. This instrument combines an optimized particle inlet with mass spectrometric techniques and detection of particle-bound alkali metal is based on surface ionization technique. The concentrations of Na and K in submicron particles were followed over periods of a few weeks. Mass concentrations of alkali in ambient air varied in the range 0.02-100 ng m(-3) during the measurement periods depending on air mass history, wind direction, season, and contributions from local sources. The number of alkali-containing particles varied between 0.1 and 100 cm(-3). Most detected individual particles contained a relatively small amount of Na, and few particles had sufficient Na content to be identified as pure sea-salt particles. The detected aerosol was concluded to be dominated by emissions from combustion of biomass and fossil fuels, with a significant contribution from sea-salt particles only during intrusion of marine air. This conclusion was supported by backward air mass trajectories and calculated K/Na weight ratios that generally agreed well with earlier measurements in urban environments. (c) 2005 Elsevier Ltd. All rights reserved.
|
|
| 7. |
- Svane, Maria, 1957, et al.
(författare)
-
Online measurements of individual alkali-containing particles formed in biomass and coal combustion: Demonstration of an instrument based on surface ionization technique
- 2005
-
Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 19:2, s. 411-417
-
Tidskriftsartikel (refereegranskat)abstract
- Online measurements of individual alkali-containing submicrometer particles in a circulating fluidized bed (CFB) combustion facility are presented. A recently developed particle beam mass spectrometer based on surface ionization technique is demonstrated and its performance during a field campaign in a 12 MW CFB reactor operating under atmospheric conditions is discussed. The boiler was fired with a biomass fuel consisting of a mixture of wood chips and pellets. During part of the campaign K2CO3, HCl, and SO2 were also added to the fuel to investigate their influence on alkali-related processes. Size-selected particles with diameters of 50-300 nm in general had high potassium content, while sodium, rubidium, and cesium were present as minor constituents. Particles formed by recondensation of compounds evaporated during the combustion process could be distinguished from fly ash particles on the basis of their potassium and sodium contents. The number of alkali-containing particles increased when the K, Cl, and S fluxes into the boiler increased, and the trend was confirmed by independent measurements of the total particle concentrations in the flue gas. The concentration of potassium bound to submicrometer particles was found to be in the range 0.8-13 mg/m(3) under the studied operating conditions. When the facility was instead fired with bituminous coal as a fuel, the relative concentration of sodium compared with potassium was higher, and a larger fraction of the alkali compounds were found in fly ash particles. The particle beam mass spectrometer is concluded to accurately provide online information on particle-bound alkali concentrations under the conditions typically prevailing at a commercial-size boiler, and the possibilities for future research and technical development are discussed.
|
|
| 8. |
|
|
