Positron-inert gas differential elastic scattering

Measurements are being made in a crossed beam experiment of the relative elastic differential cross section (DCS) for 5 to 300 eV positrons scattering from inert gas atoms (He, Ne, Ar, Kr, and Xe) in the angular range from 30 to 134 deg. Results obtained at energies around the positronium (Ps) formation threshold provide evidence that Ps formation and possibly other inelastic channels have an effect on the elastic scattering channel

Scattering of positrons and electrons by alkali atoms

Absolute total scattering cross sections (Q sub T's) were measured for positrons and electrons colliding with sodium, potassium, and rubidium in the 1 to 102 eV range, using the same apparatus and experimental approach (a beam transmission technique) for both projectiles. The present results for positron-sodium and -rubidium collisions represent the first Q sub T measurements reported for these collision systems. Features which distinguish the present comparisons between positron- and electron-alkali atom Q sub T's from those for other atoms and molecules (room-temperature gases) which have been used as targets for positrons and electrons are the proximity of the corresponding positron- and electron-alkali atom Q sub T's over the entire energy range of overlap, with an indication of a merging or near-merging of the corresponding positron and electron Q sub T's near (and above) the relatively low energy of about 40 eV, and a general tendency for the positron-alkali atom Q sub T's to be higher than the corresponding electron values as the projectile energy is decreased below about 40 eV

Critical points in low-energy positron-atom scattering

Critical points, which represent minima in differential scattering cross sections as a function of scattering angle and incident projectile energy, are theoretically predicted for elastic scattering of low-energy positrons by Ar, Kr, and Xe. It is demonstrated that these points arise due to low-energy positron diffraction effects

The effect of length of birth interval on the risk of breast cancer by subtype in grand multiparous women

BackgroundThe length of interval between successive childbirths (birth interval) might influence the incidence of breast cancer, either by stimulating or by inhibiting the factors that are responsible for the initiation of breast cancer or its early development.MethodsThis is a case-control study nested in a cohort of 47,479 Finnish grand-multiparous (GM) women born after 1934, and registered as having had at least five births before 2013. The 1354 women with breast cancer diagnosis were compared with controls (1:5) matched by parity and date of birth of the mother. Conditional logistic regression was used to estimate odds ratios of the risk of ductal and lobular breast cancer subtypes associated with each of the intervals between the 1st and 5th birth, stratified by age at diagnosis. Age at first and last birth before index date were used as covariates.ResultsIncreased intervals between the 1st and 5th births were associated with an increased risk of lobular breast cancer. In contrast, regarding ductal cancer, premenopausal women with shorter length of interval (Peer reviewe

Applicability of Modified Effective-Range Theory to positron-atom and positron-molecule scattering

We analyze low-energy scattering of positrons on Ar atoms and N2 molecules using Modified Effective-Range Theory (MERT) developped by O'Malley, Spruch and Rosenberg [Journal of Math. Phys. 2, 491 (1961)]. We use formulation of MERT based on exact solutions of Schroedinger equation with polarization potential rather than low-energy expansions of phase shifts into momentum series. We show that MERT describes well experimental data, provided that effective-range expansion is performed both for s- and p-wave scattering, which dominate in the considered regime of positron energies (0.4 - 2 eV). We estimate the values of the s-wave scattering lenght and the effective range for e+ - Ar and e+ - N2 collisions.Comment: RevTeX, 4 pages, 2 figure

Incidence of cancer among grand multiparous women in Finland with special focus on non-gynaecological cancers : A population-based cohort study

Background. Many studies have previously revealed evidence of an association between grand multiparity (five or more deliveries) and gynaecological cancer. Oestrogen has an impact on cancer formation and the amount of circulating oestrogen is significantly higher during pregnancy. Also the lifestyle of grand multiparous women differs somewhat from the average population. Considering these factors it is plausible that also non-gynaecological cancers are associated with multiparity. The aim of our study was to determine cancer incidence among grand multiparous women, with special attention to non-gynaecological cancers. Material and methods. All 102 541 women alive in 1974-2011 and having had at least five deliveries were identified in the Finnish Population Register and followed up for cancer incidence through the Finnish Cancer Registry to the end of 2011. Standardised incidence ratios (SIRs) were defined as ratios between observed and expected numbers of cases, the latter ones based on incidence in the entire Finnish female population. Results. The overall incidence of non-gynaecological cancers was the same as in the reference population (SIR 0.98, 95% confidence interval 0.90-1.06). The incidence of cancers of the gall-bladder (SIR 1.42, 1.26-1.58), biliary tract (1.19, 1.04-1.35) and kidney (1.22, 1.14-1.31) was increased. There were significantly fewer cases than expected of urinary bladder cancer (SIR 0.70, 0.61-0.78), lung cancer (0.87, 0.81-0.92), colon cancer (0.94, 0.89-0.99) and all types of skin cancers. As a consequence of the decreased incidence of gynaecological cancers (SIR 0.74, 0.71-0.77) and breast cancer (0.60, 0.58-0.61), the SIR for cancer overall was 0.84 (0.83-0.85). Conclusion. The study demonstrated that grand multiparous women have a similar overall risk of non-gynaecological cancers as other women, despite significant differences in some specific forms of cancer.Peer reviewe

Palaeoecological evidence of changes in vegetation and climate during the Holocene in the pre-Polar Urals, northeast European Russia

This study investigated Holocene tree-line history and climatic change in the pre-Polar Urals, northeast European Russia. A sediment core from Mezhgornoe Lake situated at the present-day alpine tree-line was studied for pollen, plant macrofossils, Cladocera and diatoms. A peat section from Vangyr Mire in the nearby mixed mountain taiga zone was analysed for pollen. The results suggest that the study area experienced a climatic optimum in the early Holocene and that summer temperatures were at least 2°C warmer than today. Tree birch immigrated to the Mezhgornoe Lake area at the onset of the Holocene. Mixed spruce forests followed at ca. 9500-9000 14C yr BP. Climate was moist and the water level of Mezhgornoe Lake rose rapidly. The hypsithermal phase lasted until ca. 5500-4500 14C yr BP, after which the mixed forest withdrew from the Mezhgornoe catchment as a result of the climate cooling. The gradual altitudinal downward shift of vegetation zones resulted in the present situation, with larch forming the tree-line

Absent Toll-like receptor-9 expression predicts poor prognosis in renal cell carcinoma

<p>Abstract</p> <p>Background</p> <p>Toll-like receptor 9 (TLR9) is a cellular DNA-receptor whose activation with cognate ligands triggers an immune reaction, with increased production of inflammatory cytokines. The aim of this study was to examine the expression of TLR9 in renal cell carcinoma (RCC), which is generally renowned of its immunogenic nature. We also evaluated the prognostic value of TLR9 in RCC.</p> <p>Methods</p> <p>TLR9 expression in RCC was characterized with immunohistochemistry in a retrospective study population of 152 RCC patients who underwent renal surgery. The TLR9 staining intensity was compared with clinical parameters.</p> <p>Results</p> <p>Of the studied tumours, 112 (81%) exhibited cytoplasmic TLR9 immunostaining. No association was detected between cytoplasmic TLR9 immunoexpression intensity and stage, nuclear grade, histological subtype or tumour necrosis. Cytoplasmic TLR9 immunoexpression was, however, a marker of favourable RCC specific survival both in univariate analysis and in multivariate regression model.</p> <p>Conclusions</p> <p>We conclude that TLR9 expression is an independent prognostic marker of RCC and the absence of TLR9 expression is related to poorer prognosis in RCC.</p

Outcome of oral immunotherapy for persistent cow's milk allergy from 11 years of experience in Finland

Background: The safety and efficacy of long-term milk oral immunotherapy (OIT) in Finnish children with persistent cow's milk allergy (CMA) were evaluated in an open-label, non-randomized study. Methods: During the 11-year study, 296 children aged 5 years or older with immunoglobulin E (IgE)-mediated CMA started milk OIT. Follow-up data were collected at three time points: the post-buildup phase, 1 year thereafter, and at the cross-sectional long-term follow-up between January 2016 and December 2017. Patients were divided according to baseline milk-specific IgE (sIgE) level and by the amount of milk consumption at the long-term follow-up. The high-dose group consumed >= 2 dL of milk daily, while the failure group consumed Results: Out of the initial study group, 244/296 (83%) patients participated in the long-term follow-up. Among these patients, 136/244 (56%) consumed >= 2 dL of milk daily. The median follow-up time was 6.5 years. Of the recorded markers and clinical factors, the baseline milk sIgE level was most associated with maintaining milk OIT (P <0.001). Respiratory symptoms in the post-buildup phase increased the risk of treatment failure (OR 3.5, 95% CI: 1.5-8.1, P = 0.003) and anaphylaxis (OR 14.3, 95% CI: 1.8-114, P = 0.01). Conclusion: More than half of the patients were able to maintain the targeted milk dose in their daily diet. Baseline milk sIgE level and reactivity during the early treatment stage strongly predicted the long-term outcome and safety of milk OIT.Peer reviewe