738 research outputs found
Microarray technology and its effect on breast cancer (re)classification and prediction of outcome
SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Binary coalescence from case A evolution -- mergers and blue stragglers
We constructed some main-sequence mergers from case A binary evolution and
studied their characteristics via Eggleton's stellar evolution code. Both total
mass and orbital angular momentum are conservative in our binary evolutions.
Some mergers might be on the left of the ZAMS as defined by normal surface
composition on a CMD because of enhanced surface helium content. The study also
shows that central hydrogen content of the mergers is independent of mass. As a
consequence, we fit the formula of magnitude and B-V of the mergers when they
return back to thermal equilibrium with maximum error 0.29 and 0.037,
respectively. Employing the consequences above, we performed Monte Carlo
simulations to examine our models in NGC 2682 and NGC 2660. In NGC 2682, binary
mergers from our models cover the region with high luminosity, but its
importance is much less than that of AML. Our results are well-matched to the
observations of NGC2660 if there is about 0.5Mo of mass loss in the merger
process.Comment: 14 pages, 12 figures. accepted by MNRA
Effect of convective outer layers modeling on non-adiabatic seismic observables of delta Scuti stars
The identification of pulsation modes in delta Scuti stars is mandatory to
constrain the theoretical stellar models. The non-adiabatic observables used in
the photometric identification methods depend, however,on convection modeling
in the external layers. Our aim is to determine how the treatment of convection
in the atmospheric and sub-atmospheric layers affects the mode identification,
and what information about the thermal structure of the external layers can be
obtained from amplitude ratios and phase lags in Str\"omgren photometric bands.
We derive non-adiabatic parameters for delta Scuti stars by using, for the
first time, stellar models with the same treatment of convection in the
interior and in the atmosphere. We compute classical non-gray mixing length
models, and as well non-gray ``Full Spectrum of Turbulence'' models.
Furthermore, we compute the photometric amplitudes and phases of pulsation by
using the colors and the limb-darkening coefficents as derived from the same
atmosphere models used in the stellar modeling. We show that the non-adiabatic
phase-lag is mainly sensitive to the thermal gradients in the external layers,
(and hence to the treatment of convection), and that this sensitivity is also
clearly reflected in the multi-color photometric phase differences.Comment: 14 pag. 19 figs. accepted for publication in Astronomy and
Astrophysic
Southeast of What? Reflections on SEALS\u27 Success
In epidemiologic studies, measurement error in dietary variables often attenuates association between dietary intake and disease occurrence. To adjust for the attenuation caused by error in dietary intake, regression calibration is commonly used. To apply regression calibration, unbiased reference measurements are required. Short-term reference measurements for foods that are not consumed daily contain excess zeroes that pose challenges in the calibration model. We adapted two-part regression calibration model, initially developed for multiple replicates of reference measurements per individual to a single-replicate setting. We showed how to handle excess zero reference measurements by two-step modeling approach, how to explore heteroscedasticity in the consumed amount with variance-mean graph, how to explore nonlinearity with the generalized additive modeling (GAM) and the empirical logit approaches, and how to select covariates in the calibration model. The performance of two-part calibration model was compared with the one-part counterpart. We used vegetable intake and mortality data from European Prospective Investigation on Cancer and Nutrition (EPIC) study. In the EPIC, reference measurements were taken with 24-hour recalls. For each of the three vegetable subgroups assessed separately, correcting for error with an appropriately specified two-part calibration model resulted in about three fold increase in the strength of association with all-cause mortality, as measured by the log hazard ratio. Further found is that the standard way of including covariates in the calibration model can lead to over fitting the two-part calibration model. Moreover, the extent of adjusting for error is influenced by the number and forms of covariates in the calibration model. For episodically consumed foods, we advise researchers to pay special attention to response distribution, nonlinearity, and covariate inclusion in specifying the calibration model
Long-acting κ opioid antagonists nor-BNI, GNTI and JDTic: pharmacokinetics in mice and lipophilicity
Background: Nor-BNI, GNTI and JDTic induce κ opioid antagonism that is delayed by hours and can persist for months. Other effects are transient. It has been proposed that these drugs may be slowly absorbed or distributed, and may dissolve in cell membranes, thus slowing elimination and prolonging their effects. Recent evidence suggests, instead, that they induce prolonged desensitization of the κ opioid receptor. Methods To evaluate these hypotheses, we measured relevant physicochemical properties of nor-BNI, GNTI and JDTic, and the timecourse of brain and plasma concentrations in mice after intraperitoneal administration (using LC-MS-MS). Results: In each case, plasma levels were maximal within 30 min and declined by >80% within four hours, correlating well with previously reported transient effects. A strong negative correlation was observed between plasma levels and the delayed, prolonged timecourse of κ antagonism. Brain levels of nor-BNI and JDTic peaked within 30 min, but while nor-BNI was largely eliminated within hours, JDTic declined gradually over a week. Brain uptake of GNTI was too low to measure accurately, and higher doses proved lethal. None of the drugs were highly lipophilic, showing high water solubility (> 45 mM) and low distribution into octanol (log D7.4 7% unbound). JDTic showed P-gp-mediated efflux; nor- BNI and GNTI did not, but their low unbound brain uptake suggests efflux by another mechanism. Conclusions: The negative plasma concentration-effect relationship we observed is difficult to reconcile with simple competitive antagonism, but is consistent with desensitization. The very slow elimination of JDTic from brain is surprising given that it undergoes active efflux, has modest affinity for homogenate, and has a shorter duration of action than nor-BNI under these conditions. We propose that this persistence may result from entrapment in cellular compartments such as lysosomes
A multimarker QPCR-based platform for the detection of circulating tumour cells in patients with early-stage breast cancer
BACKGROUND: The detection of circulating tumour cells (CTCs) has been linked with poor prognosis in advanced breast cancer. Relatively few studies have been undertaken to study the clinical relevance of CTCs in early-stage breast cancer. METHODS: In a prospective study, we evaluated CTCs in the peripheral blood of 82 early-stage breast cancer patients. Control groups consisted of 16 advanced breast cancer patients and 45 healthy volunteers. The CTC detection was performed using ErbB2/EpCAM immunomagnetic tumour cell enrichment followed by multimarker quantitative PCR (QPCR). The CTC status and common clinicopathological factors were correlated to relapse-free, breast cancer-related and overall survival. RESULTS: Circulating tumour cells were detected in 16 of 82 (20%) patients with early-stage breast cancer and in 13 out of 16 (81%) with advanced breast cancer. The specificity was 100%. The median follow-up time was 51 months (range: 17 -60). The CTC positivity in early-stage breast cancer patients resulted in significantly poorer relapse-free survival (log rank test: P ¼ 0.003) and was an independent predictor of relapse-free survival (multivariate hazard ratio ¼ 5.13, P ¼ 0.006, 95% CI: 1.62 -16.31). CONCLUSION: The detection of CTCs in peripheral blood of early-stage breast cancer patients provided prognostic information for relapse-free survival
Marker genes for circulating tumour cells predict survival in metastasized breast cancer patients
We investigated the prognostic significance of circulating breast cancer cells in peripheral blood detected by quantitative RT-PCR of marker genes in patients with advanced breast cancer. Blood samples from 94 breast cancer patients with metastatic disease (M1) were examined for circulating tumour cells by studying the mRNA expression of CK19, p1B, PS2 and EGP2 by real-time PCR. Using a score function, developed for predicting circulating tumour cells by quadratic discriminant analysis (QDA), the four expression levels were combined into a single discriminant value. Tumour cells were present in 24 out of 94 (31%) of the patients. In 77% (72 out of 94) of the patients distant metastatic disease was localised in the bone. In 36% (26 out of 72) of the patients with bone metastases at the time of blood sampling, a positive QDA for the four genes was found, in contrast to only 14% (three out of 22) without bone involvement. Overall survival rates by Kaplan-Meier revealed no prognostic effect for the presence of bone metastases (P=0.93). However, patients with a positive QDA value did have a progression-free survival at 1 year of 3% and overall survival at 2 years of 17%, against 22 and 36% for patients with a negative QDA value (P=0.015 and 0.0053, respectively). Breast cancer patients with metastatic disease have a significantly worse progression-free and overall survival when circulating tumour cells can be detected in their peripheral bloo
Designing a research infrastructure on dietary intake and its determinants
Research on dietary intake and its determinants is crucial for an adequate response to the current epidemic of diet-related non-communicable chronic diseases. In order to respond to this challenge, the RICHFIELDS project was tasked with designing a research infrastructure (RI) that connects data on dietary intake of consumers in Europe, and its determinants, collected using apps and wearable sensors, from behavioural laboratories and experimental facilities and from other RIs. The main output of the project, an RI design, describes interfaces (portals) to collect data, a meta-database and a data-model to enable data linkage and sharing. The RICHFIELDS project comprises three phases, each consisting of three work packages, and an overarching methodological support work package. Phase 1 focused on data generated by consumers (e.g. collected by apps and sensors) relating to the purchase, preparation and consumption of food. Phase 2 focused on data generated by organisations such as businesses (e.g. retail data), government (e.g. procurement data) and experimental research facilities (e.g. virtual supermarkets). Phases 1 and 2 provided Phase 3 with insights on data types and design requirements, including the business models, data integration and management systems and governance and ethics. The final design will be used in the coming years to build an RI for the scientific research community, policy makers and businesses in Europe. The RI will boost interdisciplinary multi-stakeholder research through harmonisation and integration of data on food behaviour.</p
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