10,847 research outputs found
Prevalence of incidental breast cancer and precursor lesions in autopsy studies: A systematic review and meta-analysis
Abstract Background Autopsy studies demonstrate the prevalence pool of incidental breast cancer in the population, but estimates are uncertain due to small numbers in any primary study. We aimed to conduct a systematic review of autopsy studies to estimate the prevalence of incidental breast cancer and precursors. Methods Relevant articles were identified through searching PubMed and Embase from inception up to April 2016, and backward and forward citations. We included autopsy studies of women with no history of breast pathology, which included systematic histological examination of at least one breast, and which allowed calculation of the prevalence of incidental breast cancer or precursor lesions. Data were pooled using logistic regression models with random intercepts (non-linear mixed models). Results We included 13 studies from 1948 to 2010, contributing 2363 autopsies with 99 cases of incidental cancer or precursor lesions. More thorough histological examination (â„20 histological sections) was a strong predictor of incidental in-situ cancer and atypical hyperplasia (ORâ=â126·8 and 21·3 respectively, pâ<â0·001), but not invasive cancer (ORâ=â1·1, pâ=â0·75). The estimated mean prevalence of incidental cancer or precursor lesion was 19·5% (0·85% invasive cancerâ+â8·9% in-situ cancerâ+â9·8% atypical hyperplasia). Conclusion Our systematic review in ten countries over six decades found that incidental detection of cancer in situ and breast cancer precursors is common in women not known to have breast disease during life. The large prevalence pool of undetected cancer in-situ and atypical hyperplasia in these autopsy studies suggests screening programs should be cautious about introducing more sensitive tests that may increase detection of these lesions
Phosphonium-Functionalized Polymer Micelles with Intrinsic Antibacterial Activity
New approaches to treat bacterial infections are badly needed to address the increasing problem of antibiotic resistance. This study explores phosphonium-functionalized block copolymer micelles as intrinsically antibacterial polymer assemblies. Phosphonium cations with varying alkyl lengths were conjugated to the terminus of a poly(ethylene oxide)â polycaprolactone block copolymer, and the phosphonium-functionalized block copolymers were self-assembled to form micelles in aqueous solution. The size, morphology, and ζ -potential of the assemblies were studied, and their abilities to kill Escherichia coli and Staphylococcus aureus were evaluated. It was found that the minimum bactericidal concentration depended on the phosphonium alkyl chain length, and different trends were observed for Gram-negative and Gram-positive bacteria. The most active assemblies exhibited no hemolysis of red blood cells above the bactericidal concentrations, indicating that they can selectively disrupt the membranes of bacteria. Furthermore, it was possible to encapsulate and release the antibiotic tetracycline using the assemblies, providing a potential multimechanistic approach to bacterial killing
transformations in the nuclear and bioenergy sectors in Sweden, Brazil, and the United States
Most of the controversies surrounding how to structure climate change
mitigation and adaptation â including financing, what counts as action, and
how to measure progress against uncertain goals â have technological change as
an underlying assumption. Technological transformation is at the heart of
mitigation in the energy system, and technological change (cultivars and
management) will be a prime contributor to mitigation and adaptation in
agriculture and water. Therefore, the issue of governing the diffusion of GEC-
related technology is critically important. The standard analyses that assume
we just need to âget the prices rightâ are insufficient in a world where
markets are at best imperfect and equitable well-being is as much a goal as
efficiency. Our research examines the ways in technological change is guided
by such governance factors as governments (regulation and policy), firms with
existing expertise and infrastructure, international and national needs for
security, innovation networks, and leadership. We will illustrate the
determinative nature of these governance factors through case studies of two
major energy technologies â nuclear power and biofuels â in three countries â
Brazil, Sweden, and the United States. Primary data comes from interviews with
policymakers and firm managers who have been involved in these changes in the
three countries. Open-ended and structured questions about a range of driving
or enabling factors allow us to establish one or more configurations of
factors that can inform the governance of future technological change related
to mitigation and serve as the basis for further research into technological
change related to adaptation
Job spells, employer spells, and wage returns to tenure
We show that the distinction between job spells and employer spells matters for returns to tenure. Employer spells encompass between-job wage movements linked to promotions or demotions while job spells don't. Using a 1% sample of the British workforce over the period 1975-2010, we find that a significant proportion of the return to employer tenure arises due to job changes within employer spells. Conditional on tenure with employer, the return to job tenure is negative. This suggests that any positive effects of job-specific human capital on wage growth within jobs are outweighed by the effects of job changes within firms
Initial MLU Predicts the Relative Efficacy of Two Grammatical Treatments in Preschoolers With Specific Language Impairments
PurposeâWe sought to confirm predictions based on past findings that pre-treatment mean length of utterance (MLU) would predict which of two grammatical treatments would best facilitate generalized and maintained grammatical development in preschoolers with specific language impairment (SLI).
MethodâThe participants were 57 preschoolers with specific language impairment (SLI). A randomized group experiment was used. The two grammatical treatments were Broad Target Recasts (BTR) and Milieu Language Teaching (MLT). MLU was assessed at Time 1 in two conversational language samples. Growth rate of productive grammar was quantified using growth curve modeling on the Index of Productive Syntax (IPSyn) from two conversational language samples at each of 6 measurement periods.
ResultsâPredictions were confirmed for children with initially low MLU, but not for children with initially high MLUs. MLT facilitated growth of grammar better than BTR in children who were initially in Brownâs stage I. Effects maintained 5 months after treatment ended
Fast ion transport in quasisymmetric equilibria in the presence of a resonant Alfv\'{e}nic perturbation
Significant progress has been made in designing magnetic fields that provide
excellent confinement of the guiding enter trajectories of alpha particles
using quasisymmetry (QS). Given the reduction in this transport channel, we
assess the impact of resonant Alfv\'{e}n eigenmodes (AEs) on the guiding center
motion. The AE amplitudes are chosen to be consistent with experimental
measurements and large-scale simulations. We evaluate the drift resonance
condition, phase-space island width, and island overlap criterion for
quasisymmetric configurations. Kinetic Poincar\'{e} plots elucidate features of
the transport, including stiff transport above a critical perturbation
amplitude. Our analysis highlights key departures from the AE-driven transport
in tokamaks, such as the avoidance of phase-space island overlap in
quasihelical configurations and the enhanced transport due to wide phase-space
islands in low magnetic shear configurations. In configurations that are closer
to QS, with QS deviations , the transport is
primarily driven by the AE, while configurations that are further from QS,
, experience significant transport due to the
QS-breaking fields in addition to the AE
Initial MLU Predicts the Relative Efficacy of Two Grammatical Treatments in Preschoolers With Specific Language Impairments
PurposeâWe sought to confirm predictions based on past findings that pre-treatment mean length of utterance (MLU) would predict which of two grammatical treatments would best facilitate generalized and maintained grammatical development in preschoolers with specific language impairment (SLI).
MethodâThe participants were 57 preschoolers with specific language impairment (SLI). A randomized group experiment was used. The two grammatical treatments were Broad Target Recasts (BTR) and Milieu Language Teaching (MLT). MLU was assessed at Time 1 in two conversational language samples. Growth rate of productive grammar was quantified using growth curve modeling on the Index of Productive Syntax (IPSyn) from two conversational language samples at each of 6 measurement periods.
ResultsâPredictions were confirmed for children with initially low MLU, but not for children with initially high MLUs. MLT facilitated growth of grammar better than BTR in children who were initially in Brownâs stage I. Effects maintained 5 months after treatment ended
Survival in Soviet Gulags: A Secondary Analysis
One of the most common book series on the subject of Soviet Gulags is Evgenia Ginzburgâs âJourney into the Whirlwindâ and âWithin the Whirlwind.â This paper will use secondary analysis from anthology works with stories similar to Ginzburg\u27s in combination with the works of several other authors like Anne Applebaum (2011) and Geith and Jolluck (2011). It shall also examine extensively RaphaĂ«l Lemkinâs definition of genocide and how it fits to what happened in the Gulags. It shall be argued why certain situations that occurred within the Gulags fit this definition. It will also explore the intimate details and lives of the Repressed. It will clarify vividly some of the social psychological and life experiences they faced in the Gulags and what coping mechanisms they used to survive them
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