1,460 research outputs found
Resistance to chemotherapy in advanced ovarian cancer: mechanisms and current strategies
Although treatment for advanced epithelial ovarian cancer has improved over recent years with the introduction of taxaneâplatinum chemotherapy, the majority of patients will relapse, and in most the disease remains incurable. A thorough understanding of drug resistance mechanisms is needed, as this remains the largest obstacle in treating patients with recurrent disease. Multidrug resistance proteins, mismatch repair processes and alterations in the p53 pathway are examples of properties within tumour cells that may lead to drug resistance. Novel agents designed to circumvent these mechanisms (e.g. PSC 833, ONYX-015 and ADP53) are currently being investigated for ovarian cancer patients. Further improvements may result from the optimisation of existing first-line regimens with more creative schedules, perhaps involving sequential or intraperitoneal administration of existing drugs, and the incorporation of newer noncross-resistant drugs
Dark energy FRW cosmology - dynamical system reconstruction
We develop a simple method of dark energy reconstruction using a geometrical
form of the luminosity-distance relation. In this method the FRW dynamical
system with dark energy is reconstructed instead of the equation of state
parameter. We give several examples which illustrate the usefulness of our
method in fitting the redshift transition from the decelerating to accelerating
phase as the value of the Hubble function at the transition.Comment: Talk presented at Spanish Relativity Meeting 2007, Puerto de la Cruz,
Tenerife, Spain, 10-14 September 200
Dark Energy Accretion onto a Black Hole in an Expanding Universe
By using the solution describing a black hole embedded in the FLRW universe,
we obtain the evolving equation of the black hole mass expressed in terms of
the cosmological parameters. The evolving equation indicates that in the
phantom dark energy universe the black hole mass becomes zero before the Big
Rip is reached.Comment: 7 pages, no figures, errors is correcte
Photometry of SN 2002ic and Implications for the Progenitor Mass-Loss History
We present new pre-maximum and late-time optical photometry of the Type
Ia/IIn supernova 2002ic. These observations are combined with the published
V-band magnitudes of Hamuy et al. (2003) and the VLT spectrophotometry of Wang
et al. (2004) to construct the most extensive light curve to date of this
unusual supernova. The observed flux at late time is significantly higher
relative to the flux at maximum than that of any other observed Type Ia
supernova and continues to fade very slowly a year after explosion. Our
analysis of the light curve suggests that a non-Type Ia supernova component
becomes prominent days after explosion. Modeling of the non-Type Ia
supernova component as heating from the shock interaction of the supernova
ejecta with pre-existing circumstellar material suggests the presence of a
cm gap or trough between the progenitor system and the
surrounding circumstellar material. This gap could be due to significantly
lower mass-loss years prior to explosion or
evacuation of the circumstellar material by a low-density fast wind. The latter
is consistent with observed properties of proto-planetary nebulae and with
models of white-dwarf + asymptotic giant branch star progenitor systems with
the asymptotic giant branch star in the proto-planetary nebula phase.Comment: accepted for publication in Ap
Novae as a Mechanism for Producing Cavities around the Progenitors of SN 2002ic and Other SNe Ia
We propose that a nova shell ejected from a recurrent nova progenitor system
created the evacuated region around the explosion center of SN 2002ic. In this
picture, periodic shell ejections due to nova explosions on a white dwarf sweep
up the slow wind from the binary companion, creating density variations and
instabilities that lead to structure in the circumstellar medium (CSM). Our
model naturally explains the observed gap between the supernova explosion
center and the CSM in SN 2002ic, accounts for the density variations observed
in the CSM, and resolves the coincidence problem of the timing of the explosion
of SN 2002ic with respect to the apparent cessation of mass-loss in the
progenitor system. We also consider such nova outburst sweeping as a generic
feature of Type Ia supernovae with recurrent nova progenitors.Comment: Accepted to ApJL. 11 pages, 1 tabl
RELIABILITY OF CLINICAL ISOKINETIC DYNAMOMETRY IN PATHOLOGICAL ATHLETIC SHOULDERS
There have been relatively few studies of the reliability of isokinetic shoulder testing, and only Malerba et al. (1993) have investigated patients with shoulder joint pathology (patients ranged in activity level from sedentary to highly active). Furthermore, all existing studies have involved a level of procedural standardisation which, while desirable, cannot always be achieved in a clinical environment, that is, where most isokinetic testing is performed. Therefore, the aim of this study was to assess the reliability of isokinetic testing of pathological athletic shoulders in a clinical environment, under routine clinical conditions. Twenty-two athletic patients (mean age 26 years) presenting with a range of pathologies including post-subluxation, post-dislocation, and post-surgical reconstruction were tested. Patients were tested on two occasions, separated by a time interval during which their clinical status was not expected to change (most tests were one week apart; mean interval 10 days). Bilateral isokinetic strength of the shoulder internal and external rotators were tested on a Cybex 6000 dynamometer at 2.09 and 4.19 radianslsecond (concentric) and 2.09 radianslsecond (eccentric). Patients were tested in a seated position, in 45 degrees of shoulder abduction, and 90 degrees of elbow flexion. Tests were performed in essentially the same fashion on each occasion by the same tester. However, the constraints of a busy clinical environment meant that precise control and exact replication may not have always been achieved. Intra-class correlation coefficients (ICC) for absolute concentric peak torque, work, and average power were all above 0.9. Eccentric ICCs were generally above 0.8. These values are as high as, or higher than, those reported in the literature for studies of healthy subjects conducted under more stringent conditions than can be achieved in a clinical environment. The reliability of commonly calculated ratios, such as agonistlantagonist and involved/uninvolved, was lower than that of the constituent absolute scores, and in some cases were quite poor. Caution is therefore warranted in the use of such ratios. Malerba JL; Adam ML, Harris BA, Krebs DE (1993) Reliability of dynamic and isometric testing of shoulder external and internal rotators. Journal of Orthopaedic and Sports Physical Therapy 18543-552
Mitigating the risk of Zika virus contamination of raw materials and cell lines in the manufacture of biologicals
Ensuring the virological safety of biologicals is challenging due to the risk of viral contamination of raw materials and cell
banks, and exposure during in-process handling to known and/or emerging viral pathogens. Viruses may contaminate raw
materials and biologicals intended for human or veterinary use and remain undetected until appropriate testing measures
are employed. The outbreak and expansive spread of the mosquito-borne flavivirus Zika virus (ZIKV) poses challenges to
screening human- and animal -derived products used in the manufacture of biologicals. Here, we report the results of an in
vitro study where detector cell lines were challenged with African and Asian lineages of ZIKV. We demonstrate that this
pathogen is robustly detectable by in vitro assay, thereby providing assurance of detection of ZIKV, and in turn underpinning
the robustness of in vitro virology assays in safety testing of biologicals
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