5 research outputs found
Methods for Cancellation of Apparent Cerenkov Radiation Arising From SME Models and Separability of Schrödinger’s Equation Using Exotic Potentials in Parabolic Coordinates
In an attempt to merge the two prominent areas of physics: The Standard Model and General Relativity, there have been many theories for the underlying physics that may lead to Lorentz- and CPT-symmetry violations. At the present moment, technology allows numerous types of Planck-sensitive tests of these symmetries in a range of physical systems.
We address a curiosity in isotropic CPT- and Lorentz-violating electrodynamics where there is a kinematic allowance for Cerenkov radiation of a charged particle in a vacuum moving with uniform motion. This however, should not be the case as it is known that constant motion in a vacuum should not cause the particle to lose any energy. Taking Fourier transforms of the modified magnetic field confirms the cancellation of the apparent radiation. The Fourier transform can be used to show that modes for short and long wavelengths cancel.
In the second area of research we focus on solutions of the Schrödinger equation which may be found by separation of variables in more than one coordinate system. This class of potentials includes a number of important examples, including the isotropic harmonic oscillator and the Coulomb potential. There are multiple separable Hamiltonians that exhibit a number of interesting features, including “accidental” degeneracies in their bound state spectra and often classical bound state orbits that always close. We examine another potential, for which the Schrödinger equation is separable in both cylindrical and parabolic coordinates: a z-independent V ∝ 1/p2 = 1/ (x2 + y2) in three dimensions. All the persistent, bound classical orbits in this potential close, because all other orbits with negative energies fall to the center at ρ = 0. When separated in parabolic coordinates, the Schrödinger equation splits into three individual equations, two of which are equivalent to the radial equation in a Coulomb potential—one equation with an attractive potential, the other with an equally strong repulsive potential
First-line panitumumab plus irinotecan/5-fluorouracil/leucovorin treatment in patients with metastatic colorectal cancer
Purpose Panitumumab monotherapy is approved for KRAS wild-type (WT) metastatic colorectal cancer (mCRC) progressing after standard chemotherapy. This study evaluated first-line panitumumab plus FOLFIRI in patients with mCRC. Methods In this phase II, single-arm study, panitumumab (6 mg/kg) and FOLFIRI [irinotecan (180 mg/m(2)) and leucovorin (400 mg/m(2)) followed by a 5-fluorouracil 400 mg/m(2) bolus and a 2,400-3,000 mg/m(2) continuous infusion] were administered every 14 days until progression. Data were analysed descriptively overall and by tumour KRAS status. Results KRAS data were available for 145/154 (94%) patients: 59% KRAS WT and 41% mutant (MT); mean follow-up was 39.5 versus 35.8 weeks, respectively. Objective responses occurred in 49% of patients: 56% versus 38% in the KRAS WT versus MT groups [(18% difference (95% CI 1-35%); odds ratio 2.1 (95% CI 1.0-4.4)]; median duration of response was 13.0 versus 7.4 months. More patients in the WT group underwent R0 resection (8% vs. 5%); median progression-free survival also favoured this group (8.9 vs. 7.2 months). The most common adverse events (any grade) were integument toxicities (98%), diarrhoea (79%) and stomatitis/oral mucositis (51%). Conclusions As expected, consistently favourable efficacy was observed in patients with KRAS WT versus MT tumours receiving first-line panitumumab plus FOLFIRI treatment