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- Tajkumar, T, et al.
(författare)
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Cervical carcinoma and sexual behavior: collaborative reanalysis of individual data on 15,461 women with cervical carcinoma and 29,164 women without cervical carcinoma from 21 epidemiological studies
- 2009
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Ingår i: Cancer Epidemiology Biomarkers & Prevention. - 1538-7755. ; 18:4, s. 1060-1069
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Tidskriftsartikel (refereegranskat)abstract
- High-risk human papillomavirus (HPV) types cause most cervical carcinomas and are sexually transmitted. Sexual behavior therefore affects HPV exposure and its cancer sequelae. The International Collaboration of Epidemiological Studies of Cervical Cancer has combined data on lifetime number of sexual partners and age at first sexual intercourse from 21 studies, or groups of studies, including 10,773 women with invasive cervical carcinoma, 4,688 women with cervical intraepithelial neoplasia grade 3 (CIN3)/carcinoma in situ, and 29,164 women without cervical carcinoma. Relative risks for invasive cancer and CIN3 were estimated by conditional logistic regression. Risk of invasive cervical carcinoma increased with lifetime number of sexual partners (P for linear trend <0.001). The relative risk for > or =6 versus 1 partner, conditioned on age, study, and age at first intercourse, was 2.27 [95% confidence interval (95% CI), 1.98-2.61] and increased to 2.78 (95% CI, 2.22-3.47) after additional conditioning on reproductive factors. The risk of invasive cervical carcinoma increased with earlier age at first intercourse (P for linear trend <0.001). The relative risk for age at first intercourse < or =14 versus > or =25 years, conditioned on age, study, and lifetime number of sexual partners was 3.52 (95% CI, 3.04-4.08), which decreased to 2.05 (95% CI, 1.54-2.73) after additional conditioning on reproductive factors. CIN3/carcinoma in situ showed a similar association with lifetime number of sexual partners; however, the association with age at first intercourse was weaker than for invasive carcinoma. Results should be interpreted with caution given the strong correlation between sexual and reproductive factors and the limited information on HPV status.
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- Rajkumar, T, et al.
(författare)
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Carcinoma of the cervix and tobacco smoking: Collaborative reanalysis of individual data on 13,541 women with carcinoma of the cervix and 23,017 women without carcinoma of the cervix from 23 epidemiological studies - International collaboration of epidemiological studies of cervical cancer
- 2006
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136. ; 118:6, s. 1481-1495
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Tidskriftsartikel (refereegranskat)abstract
- Tobacco smoking has been classified as a cause of cervical cancer, but the effect of different patterns of smoking on risk is unclear. The International Collaboration of Epidemiological Studies of Cervical Cancer has brought together and combined individual data on 13,541 women with and 23,017 women without cervical carcinoma, from 23 epidemiological studies. Relative risks (RRs) and 95% confidence intervals (CIs) of carcinoma of the cervix in relation to tobacco smoking were calculated with stratification by study, age, sexual partners, age at first intercourse, oral contraceptive use and parity. Current smokers had a significantly increased risk of squamous cell carcinoma of the cervix compared to never smokers (RR = 1.60 (95% CI: 1.48-1.73), p < 0.001). There was increased risk for past smokers also, though to a lesser extent (RR = 1.12 (1.01-1.25)), and there was no clear trend with time since stopping smoking (p-trend = 0.6). There was no association between smoking and adenocarcinoma of the cervix (RR = 0.89 (0.74-1.06) and 0.89 (0.72-1.10) for current and past smokers respectively), and the differences between the RRs for smoking and squamous cell and adenocarcinoma were statistically significant (current smoking p < 0.001 and past smoking p = 0.01). In current smokers, the RR of squamous cell carcinoma increased with increasing number of cigarettes smoked per day and also with younger age at starting smoking (p < 0.001 for each trend), but not with duration of smoking (p-trend = 0.3). Eight of the studies had tested women for cervical HPV-DNA, and in analyses restricted to women who tested positive, there was a significantly increased risk in current compared to never smokers for squamous cell carcinoma (RR = 1.95 (1.43-2.65)), but not for adenocarcinoma (RR = 1.06 (0.14-7.96)). In summary, smokers are at an increased risk of squamous cell but not of adenocarcinoma of the cervix. The risk of squamous cell carcinoma increases in current smokers with the number of cigarettes smoked per day and with younger age at starting smoking.
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- Lee, Myeong H., et al.
(författare)
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Crystal structure, electronic structure, and vibrational properties of MAlSiH (M=Ca,Sr,Ba) : Hydrogenation-induced semiconductors from the AlB2-type alloys MAlSi
- 2008
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 78:19, s. 195209-
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Tidskriftsartikel (refereegranskat)abstract
- Superconducting AlB2-type silicides CaAlSi, SrAlSi, and BaAlSi (MAlSi) absorb hydrogen and form semiconducting monohydrides where hydrogen is exclusively attached to Al. This induces a metal-nonmetal transition which is accompanied with only a minor rearrangement of the metal atoms. We report the synthesis and structure determination of CaAlSiH and BaAlSiH as well as a first-principles study of the electronic structure and vibrational property changes associated with the metal-nonmetal transition. We find that incorporation of H in MAlSi removes the partly occupied antibonding pi(*) band responsible for metallic behavior and turns it into an energetically low-lying Al-H bonding band. The fully occupied bonding pi band in MAlSi changes to a weakly dispersed band with Si p(z) (lone-pair) character in the hydrides, which becomes located below the Fermi level. The soft phonon mode in MAlSi pivotal for the superconducting properties stiffens considerably in the hydride. This mode is associated with the out-of-plane Al-Si vibration and is most affected by the formation of the Al-H bond. The mode of the Al-Si in-plane vibration, however, is unaffected, indicating that the Al-Si bond is equally strong in the metallic precursor and the semiconducting hydride. Al-H modes for MAlSiH are weakly dispersed. The frequencies of the stretching mode are around 1200 cm(-1) and virtually invariant to the M environment, indicating a covalent but weak Al-H interaction, which is interpreted as a dative bond from hydridic hydrogen to Al [Al <- H1-].
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- Lu, W, et al.
(författare)
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Independent determination of In and N concentrations in GaInNAs alloys
- 2009
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 24:10, s. 105016-
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution x-ray diffraction (HRXRD) and photoreflectance ( PR) spectroscopy were used to independently determine the In and N concentrations in GaInNAs alloys grown by solid-source molecular beam epitaxy (SSMBE). The lattice constant and bandgap energy can be expressed as two independent equations in terms of the In and N concentrations, respectively. The HRXRD measurement provided the lattice constant and the PR measurement extracted the bandgap energy. By simultaneously solving these two equations, we have determined the In and N concentrations with the error as small as 0.001.
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- Sallis, James F, et al.
(författare)
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Neighborhood environments are related to physical activity among adults in 11 countries
- 2009
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Ingår i: American Journal of Preventive Medicine. - 0749-3797 .- 1873-2607. ; 36:6, s. 484-490
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundUnderstanding environmental correlates of physical activity can inform policy changes. Surveys were conducted in 11 countries using the same self-report environmental variables and the International Physical Activity Questionnaire, allowing analyses with pooled data.MethodsThe participating countries were Belgium, Brazil, Canada, Colombia, China (Hong Kong), Japan, Lithuania, New Zealand, Norway, Sweden, and the U.S., with a combined sample of 11,541 adults living in cities. Samples were reasonably representative, and seasons of data collection were comparable. Participants indicated whether seven environmental attributes were present in their neighborhood. Outcomes were measures of whether health-related guidelines for physical activity were met. Data were collected in 2002–2003 and analyzed in 2007. Logistic regression analyses evaluated associations of physical activity with environmental attributes, adjusted for age, gender, and clustering within country.ResultsFive of seven environmental variables were significantly related to meeting physical activity guidelines, ranging from access to low-cost recreation facilities (OR=1.16) to sidewalks on most streets (OR=1.47). A graded association was observed, with the most activity–supportive neighborhoods having 100% higher rates of sufficient physical activity compared to those with no supportive attributes.ConclusionsResults suggest neighborhoods built to support physical activity have a strong potential to contribute to increased physical activity. Designing neighborhoods to support physical activity can now be defined as an international public health issue.
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