999 resultados para SPONTANEOUS POLARIZATION


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Reports on two studies designed to assess the making of life satisfaction judgements. Findings suggested that while life satisfaction judgements are indeed made in everyday life, such judgements are based on thinking that is limited in nature. Overall, the second study also suggested that the results typically obtained in standard life satisfaction studies may, in part, be an artifact of the methodology they employ.

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Background: Medical management and expectant care have been considered possible alternatives to surgical evacuation of the uterus for first trimester spontaneous miscarriage in recent years.

Aim: To compare the effectiveness and safety of medical and expectant management with surgical management for first trimester incomplete or inevitable miscarriage.

Methods: Forty women were recruited following diagnosis of incomplete or inevitable miscarriage, and randomised to surgical, medical or expectant care via an off-site, computerised enrolment system. The primary outcome was the effectiveness of medical (vaginal misoprostol) and expectant management relative to surgical evacuation, assessed at 10–14 days and 8 weeks post-recruitment. Infection, pain, bleeding, anxiety, depression, physical and emotional recovery were assessed also. Analysis was by intention-to-treat.

Results: Effectiveness at 8 weeks was lower for medical (80.0%) and expectant (78.6%) than for surgical management (100.0%). Two women in the medical group had confirmed infections. Bleeding lasted longer in the expectant group than in the surgical group. There were no significant differences in pain, physical recovery, anxiety or depression between the groups. 54.6%, 42.9% and 57.1% of the surgical, medical and expectant groups respectively would opt for the same treatment again.

Conclusion: Expectant care appears to be sufficiently safe and effective to be offered as an option for women. Medical management might carry a higher risk of infection than surgical or expectant care.

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13C nuclear magnetic resonance (n.m.r.) has been used to study polypyrrole and N-substituted polypyrrole in the solid state. The extent of oxidation appears to be counterion-dependent; in particular, the quinoid structure appears favoured in the films prepared with dodecyl sulfate. Resonances associated with the quinoid unit are lost upon reduction of the polypyrrole film, which supports the idea that the quinoid structure is associated with the oxidized form of polypyrrole. N-substituted polypyrroles have a more distinct resonance at 110 ppm, which is linked to lower degrees of oxidation or charge delocalization in these systems. The decrease in conductivity of polypyrrole upon thermal ageing in air is associated with both the loss of counterion (‘thermal dedoping’) and the decomposition of the quinoid structure in the polymer backbone. There is no indication of carbonyl formation in the solid-state n.m.r. spectra obtained in the present study.

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According to dielectric spectroscopy measurements, ionic liquids (ILs) have rather modest dielectric constants that reflect contributions from distortion and electronic polarization caused by the molecular polarizability as well as the orientation polarization caused by the permanent dipole moment of the ions. To understand the relative importance of these various contributions, the electronic polarizabilities of 27 routinely used ionic liquid ions of different symmetry and size were calculated using ab initio-based methods such as HF and MP2. Using the Clausius–Mossotti equation, these polarizabilities were then used to obtain the electronic polarization contribution (εop) to the dielectric constants of six ionic liquids, [C2mim][BF4], [C2mpyr][N(CN)2], [C2mim][CF3SO3], [EtNH3][NO3], [C2mim][NTf2] and [C2mim][EtSO4]. Theoretical εop values were compared to experimental refractive indices of these ionic liquids as well as to those of traditional molecular solvents such as water, tetrahydrofuran (THF), dimethylsulfoxide (DMSO) and formamide. The dipole moments of the ions were also calculated, and from these it is shown that the molecular reorientation component of the dielectric constants of the ionic liquids consisting of ions with small or negligible dipole moments is quite small. Thus it is concluded that a contribution from a form of “ionic polarization” must be present.

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This study provides evidence on the principal determinants of pregnancy and abortion in India using a large country-wide district-level data set (DLHS 2007). The paper provides an economic framework for the analysis of pregnancy and abortion. The study distinguishes between induced and spontaneous abortion and compares the effects of their determinants.

The results show that there are wide differences between induced and spontaneous abortions in terms of the sign and magnitude of the estimated effects of several of their determinants, most notably wealth, the woman’s age and her desire for children. The study makes a methodological contribution by proposing a trivariate probit estimation framework that recognizes the joint dependence of pregnancy and induced and spontaneous abortion, and provides evidence in support of this joint dependence.

The study reports an inverted U-shaped effect of a woman’s age on her pregnancy and both forms of abortion. The turning point in each case is quite robust to the estimation framework. A significant effect of contextual variables, at the village level, constructed from the individual responses, on a woman’s pregnancy is found. The effects are weaker in the case of induced abortion, and insignificant in the case of spontaneous abortion. The results are shown to be fairly robust. This paper extends the literature on the relation between son preference and fertility by examining the link between mother’s son preference and desire for more children with abortion rates.

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In health psychology, individuals’ judgements about health risks have almost exclusively been investigated by explicitly soliciting such judgements. Five novel methodologies were used to examine risk judgements that are made spontaneously, without prompting. The findings suggest that spontaneous risk judgements can differ in important ways from researcher solicited ones.

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We present an approach for the efficient design of polarization insensitive polymeric optical waveguide devices considering stress-induced effects. In this approach, the stresses induced in the waveguide during the fabrication process are estimated first using a more realistic model in the finite element analysis. Then we determine the perturbations in the material refractive indices caused by the stress-optic effect. It is observed that the stresses cause non-uniform optical anisotropy in the waveguide materials, which is then incorporated in the modal analysis considering a multilayer structure of waveguide. The approach is exploited in the design of a Bragg grating on strip waveguide. Excellent agreement between calculated and published experimental results confirms the feasibility of our approach in the accurate design of polarization insensitive polymer waveguide devices.

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Although many preclinical studies have implicated β3 integrin receptors (αvβ3 and αIIbβ3) in cancer progression, β3 inhibitors have shown only modest efficacy in patients with advanced solid tumours. The limited efficacy of β3 inhibitors in patients could arise from our incomplete understanding of the precise function of β3 integrin and, consequently, inappropriate clinical application. Data from animal studies are conflicting and indicate heterogeneity with respect to the relative contributions of β3-expressing tumour and stromal cell populations in different cancers. Here we aimed to clarify the function and relative contributions to metastasis of tumour versus stromal β3 integrin in clinically relevant models of spontaneous breast cancer metastasis, with particular emphasis on bone metastasis. We show that stable down-regulation of tumour β3 integrin dramatically impairs spontaneous (but not experimental) metastasis to bone and lung without affecting primary tumour growth in the mammary gland. Unexpectedly, and in contrast to subcutaneous tumours, orthotopic tumour vascularity, growth and spontaneous metastasis were not altered in mice null for β3 integrin. Tumour β3 integrin promoted migration, protease expression and trans-endothelial migration in vitro and increased vascular dissemination in vivo, but was not necessary for bone colonization in experimental metastasis assays. We conclude that tumour, rather than stromal, β3 expression is essential and is required early for efficient spontaneous breast cancer metastasis to bone and soft tissues. Accordingly, differential gene expression analysis in cohorts of breast cancer patients showed a strong association between high β3 expression, early metastasis and shorter disease-free survival in patients with oestrogen receptor-negative tumours. We propose that β3 inhibitors may be more efficacious if used in a neoadjuvant setting, rather than after metastases are established. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.