5,853 research outputs found
Use of the metastatic breast cancer progression (MBC-P) questionnaire to assess the value of progression-free survival for women with metastatic breast cancer.
While overall survival (OS) has historically been the primary endpoint for clinical trials in oncology, progression-free survival (PFS) has gained acceptance as a valuable surrogate endpoint. However, there are no known published reports about the value of PFS from the patient's perspective. We developed a questionnaire that included items regarding quality of life (QoL) and the importance of different treatment outcomes and presented hypothetical scenarios for which respondents were asked to indicate their preferences concerning treatments as they relate to PFS. 282 women with metastatic breast cancer (MBC), ranging in age from 21 to 80 years completed an online version of this questionnaire. The majority of women (66 %) had been diagnosed with MBC within the previous 3 years and 56 % had been told their MBC had progressed. When asked to rank five treatment characteristics from most important to least important, respondents ranked "extending PFS" as the second most important treatment outcome after OS. When presented with a hypothetical scenario of two women receiving different treatments, respondents preferred the treatment that resulted in longer PFS (16 vs. 12 months), even when OS and side effects were assumed to be equal. Specifically, when asked to consider which woman within the hypothetical scenario had better QoL, physical functioning, and emotional well-being, respondents more often chose the woman who experienced longer PFS (QoL: 40 vs. 6 %; physical functioning: 32 vs. 8 %; emotional well-being: 58 vs. 6 %) compared to the woman within the hypothetical scenario who had a shorter time of progression. Respondents rated their own QoL highest after being told their MBC was responding to treatment (mean score 76.6) versus after the initial diagnosis of breast cancer and MBC (68.5 and 60.3). These findings suggest that extending PFS is an important treatment outcome and, from a patient perspective, improves overall QoL, physical functioning, and emotional well-being
A theory-based approach to understanding condom errors and problems reported by men attending an STI clinic
The official published version can be accessed from the link below - Copyright @ 2008 Springer VerlagWe employed the information–motivation–behavioral skills (IMB) model to guide an investigation of correlates for correct condom use among 278 adult (18–35 years old) male clients attending a sexually transmitted infection (STI) clinic. An anonymous questionnaire aided by a CD-recording of the questions was administered. Linear Structural Relations Program was used to conduct path analyses of the hypothesized IMB model. Parameter estimates showed that while information did not directly affect behavioral skills, it did have a direct (negative) effect on condom use errors. Motivation had a significant direct (positive) effect on behavioral skills and a significant indirect (positive) effect on condom use errors through behavioral skills. Behavioral skills had a direct (negative) effect on condom use errors. Among men attending a public STI clinic, these findings suggest brief, clinic-based, safer sex programs for men who have sex with women should incorporate activities to convey correct condom use information, instill motivation to use condoms correctly, and directly enhance men’s behavioral skills for correct use of condoms
Extreme positive allometry of animal adhesive pads and the size limits of adhesion-based climbing.
Organismal functions are size-dependent whenever body surfaces supply body volumes. Larger organisms can develop strongly folded internal surfaces for enhanced diffusion, but in many cases areas cannot be folded so that their enlargement is constrained by anatomy, presenting a problem for larger animals. Here, we study the allometry of adhesive pad area in 225 climbing animal species, covering more than seven orders of magnitude in weight. Across all taxa, adhesive pad area showed extreme positive allometry and scaled with weight, implying a 200-fold increase of relative pad area from mites to geckos. However, allometric scaling coefficients for pad area systematically decreased with taxonomic level and were close to isometry when evolutionary history was accounted for, indicating that the substantial anatomical changes required to achieve this increase in relative pad area are limited by phylogenetic constraints. Using a comparative phylogenetic approach, we found that the departure from isometry is almost exclusively caused by large differences in size-corrected pad area between arthropods and vertebrates. To mitigate the expected decrease of weight-specific adhesion within closely related taxa where pad area scaled close to isometry, data for several taxa suggest that the pads' adhesive strength increased for larger animals. The combination of adjustments in relative pad area for distantly related taxa and changes in adhesive strength for closely related groups helps explain how climbing with adhesive pads has evolved in animals varying over seven orders of magnitude in body weight. Our results illustrate the size limits of adhesion-based climbing, with profound implications for large-scale bio-inspired adhesives.We are sincerely grateful to all our colleagues who readily shared published and unpublished data with us: Aaron M. Bauer, Jon Barnes, Niall Crawford, Thomas Endlein, Hanns Hagen Goetzke, Thomas E. Macrini, Anthony P. Russell & Joanna M. Smith. We also thank Casey Gilman, Dylan Briggs, Irina Showalter, Dan King and Mike Imburgia for their assistance with the collection of gecko toepad data. This study was supported by research grants from the UK Biotechnology and Biological Sciences Research Council (BB/I008667/1) to WF, the Human Frontier Science Programme (RGP0034/2012) to DI, AJC and WF, the Denman Baynes Senior Research Fellowship to DL and a Discovery Early Career Research Fellowship (DE120101503) to CJC.This is the author accepted manuscript. The final version is available from the National Academy of Sciences via http://dx.doi.org/ 10.1073/pnas.151945911
Evidence for equilibrium iron isotope fractionation by nitrate-reducing iron(II)-oxidizing bacteria
Iron isotope fractionations produced during chemical and biological Fe(II) oxidation are sensitive to the proportions and nature of dissolved and solid-phase Fe species present, as well as the extent of isotopic exchange between precipitates and aqueous Fe. Iron isotopes therefore potentially constrain the mechanisms and pathways of Fe redox transformations in modern and ancient environments. In the present study, we followed in batch experiments Fe isotope fractionations between Fe(II)_(aq) and Fe(III) oxide/hydroxide precipitates produced by the Fe(III) mineral encrusting, nitrate-reducing, Fe(II)-oxidizing Acidovorax sp. strain BoFeN1. Isotopic fractionation in ^(56)Fe/^(54)Fe approached that expected for equilibrium conditions, assuming an equilibrium Δ^(56)Fe_(Fe(OH)3–Fe(II)aq) fractionation factor of +3.0‰. Previous studies have shown that Fe(II) oxidation by this Acidovorax strain occurs in the periplasm, and we propose that Fe isotope equilibrium is maintained through redox cycling via coupled electron and atom exchange between Fe(II)_(aq) and Fe(III) precipitates in the contained environment of the periplasm. In addition to the apparent equilibrium isotopic fractionation, these experiments also record the kinetic effects of initial rapid oxidation, and possible phase transformations of the Fe(III) precipitates. Attainment of Fe isotope equilibrium between Fe(III) oxide/hydroxide precipitates and Fe(II)_(aq) by neutrophilic, Fe(II)-oxidizing bacteria or through abiologic Fe(II)_(aq) oxidation is generally not expected or observed, because the poor solubility of their metabolic product, i.e. Fe(III), usually leads to rapid precipitation of Fe(III) minerals, and hence expression of a kinetic fractionation upon precipitation; in the absence of redox cycling between Fe(II)_(aq) and precipitate, kinetic isotope fractionations are likely to be retained. These results highlight the distinct Fe isotope fractionations that are produced by different pathways of biological and abiological Fe(II) oxidation
Noise storm continua: power estimates for electron acceleration
We use a generic stochastic acceleration formalism to examine the power
() input to nonthermal electrons that cause
noise storm continuum emission. The analytical approach includes the derivation
of the Green's function for a general second-order Fermi process, and its
application to obtain the particular solution for the nonthermal electron
distribution resulting from the acceleration of a Maxwellian source in the
corona. We compare with the power observed in noise
storm radiation. Using typical values for the various parameters, we find that
, yielding an efficiency
estimate in the range 10^{-10} \lsim \eta
\lsim 10^{-6} for this nonthermal acceleration/radiation process. These
results reflect the efficiency of the overall process, starting from electron
acceleration and culminating in the observed noise storm emission.Comment: Accepted for publication in Solar Physic
Universality in solar flare and earthquake occurrence
Earthquakes and solar flares are phenomena involving huge and rapid releases
of energy characterized by complex temporal occurrence. By analysing available
experimental catalogs, we show that the stochastic processes underlying these
apparently different phenomena have universal properties. Namely both problems
exhibit the same distributions of sizes, inter-occurrence times and the same
temporal clustering: we find afterflare sequences with power law temporal
correlations as the Omori law for seismic sequences. The observed universality
suggests a common approach to the interpretation of both phenomena in terms of
the same driving physical mechanism
THE PROFILES OF JMJD3, UTX AND H3K27ME3 EXPRESSION IN PULMONARY VASCULATURE IN RAT MCT MODEL OF PAH AND HUMAN IPAH: IMPLICATIONS FOR PULMONARY ARTERIAL HYPERTENSION
Particle interactions with single or multiple 3D solar reconnecting current sheets
The acceleration of charged particles (electrons and protons) in flaring
solar active regions is analyzed by numerical experiments. The acceleration is
modelled as a stochastic process taking place by the interaction of the
particles with local magnetic reconnection sites via multiple steps. Two types
of local reconnecting topologies are studied: the Harris-type and the X-point.
A formula for the maximum kinetic energy gain in a Harris-type current sheet,
found in a previous work of ours, fits well the numerical data for a single
step of the process. A generalization is then given approximating the kinetic
energy gain through an X-point. In the case of the multiple step process, in
both topologies the particles' kinetic energy distribution is found to acquire
a practically invariant form after a small number of steps. This tendency is
interpreted theoretically. Other characteristics of the acceleration process
are given, such as the mean acceleration time and the pitch angle distributions
of the particles.Comment: 18 pages, 9 figures, Solar Physics, in pres
Increasing condom use in heterosexual men: development of a theory-based interactive digital intervention
Increasing condom use to prevent sexually transmitted infections is a key public health goal. Interventions are more likely to be effective if they are theory- and evidence-based. The Behaviour Change Wheel (BCW) provides a framework for intervention development. To provide an example of how the BCW was used to develop an intervention to increase condom use in heterosexual men (the MenSS website), the steps of the BCW intervention development process were followed, incorporating evidence from the research literature and views of experts and the target population. Capability (e.g. knowledge) and motivation (e.g. beliefs about pleasure) were identified as important targets of the intervention. We devised ways to address each intervention target, including selecting interactive features and behaviour change techniques. The BCW provides a useful framework for integrating sources of evidence to inform intervention content and deciding which influences on behaviour to target
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