A continuing education program for the general practitioner is presented that would provide a degree or certificate of advanced status on completion. This long-term program would be made possible by ...giving credit hours for continuing education courses taken, then redeeming these credits for the certificate or degree on completion. The dentist's choice in continuing education programs is protected because he can choose between programs with or without objectives, and programs that are tailored to his interests.
Oncogenic Ras is responsible for malignant transformation in a variety of tumors. Farnesylation of Ras by farnesyl-protein-transferase (FPTase) is necessary for membrane localization of Ras-proteins, ...a prerequisite for its biological activity. Although mutations in ras genes are rare in neuroblastoma inactivation of Ras by inhibition of the FPTase is of interest in neuroblastoma. In this tumor, amplification of N-myc is frequently observed and expression of N-myc is induced via Ras signaling. Farnesyl-protein-transferase of neuroblastoma cells is inhibited by alpha-hydroxyfarnesylphosphonate. In homogenates of the cell line SK-N-AS an ID50 = 6.5 microM is estimated, in SK-N-SH the ID50 is 3.4 microM. The consequences of the inhibition of FPTase on the membrane localization was examined by immunoblots. Western blots of membrane proteins analysed with H-ras and N-ras specific antibodies revealed that H-ras protein is more sensitive to the inhibition of FPTase than N-ras protein. After culturing neuroblastoma cells for 24 hrs in the presence of 20 microM alpha-hydroxyfarnesylphosphonate H-ras protein completely dissappeared from the membrane fraction whereas N-ras protein was only affected by 50%. K-ras was not detectable on Western blots of three neuroblastoma cell lines. The experiments showed that FPTase inhibitors are effective in neuroblastoma cells but for complete inactivation of N-ras stronger conditions are required than for H-ras.
We report the discovery and characterization of the transiting extrasolar planet TOI-1710\(\:\)b. It was first identified as a promising candidate by the Transiting Exoplanet Survey Satellite (TESS). ...Its planetary nature was then established with SOPHIE and HARPS-N spectroscopic observations via the radial-velocity method. The stellar parameters for the host star are derived from the spectra and a joint Markov chain Monte-Carlo (MCMC) adjustment of the spectral energy distribution and evolutionary tracks of TOI-1710. A joint MCMC analysis of the TESS light curve and the radial-velocity evolution allows us to determine the planetary system properties. From our analysis, TOI-1710\(\:\)b is found to be a massive warm super-Neptune (\(M_{\rm p}=28.3\:\pm\:4.7\:{\rm M}_{\rm Earth}\) and \(R_{\rm p}=5.34\:\pm\:0.11\:{\rm R}_{\rm Earth}\)) orbiting a G5V dwarf star (\(T_{\rm eff}=5665\pm~55\mathrm{K}\)) on a nearly circular 24.3-day orbit (\(e=0.16\:\pm\:0.08\)). The orbital period of this planet is close to the estimated rotation period of its host star \(P_{\rm rot}=22.5\pm2.0~\mathrm{days}\) and it has a low Keplerian semi-amplitude \(K=6.4\pm1.0~\mathrm{m\:s^{-1}}\); we thus performed additional analyses to show the robustness of the retrieved planetary parameters. With a low bulk density of \(1.03\pm0.23~\mathrm{g\:cm^{-3}}\) and orbiting a bright host star (\(J=8.3\), \(V=9.6\)), TOI-1710\(\:\)b is one of the best targets in this mass-radius range (near the Neptunian desert) for atmospheric characterization via transmission spectroscopy, a key measurement in constraining planet formation and evolutionary models of sub-Jovian planets.
We report the discovery of one super-Earth- (TOI-1749b) and two sub-Neptune-sized planets (TOI-1749c and TOI-1749d) transiting an early M dwarf at a distance of 100~pc, which were first identified as ...planetary candidates using data from the TESS photometric survey. We have followed up this system from the ground by means of multiband transit photometry, adaptive-optics imaging, and low-resolution spectroscopy, from which we have validated the planetary nature of the candidates. We find that TOI-1749b, c, and d have orbital periods of 2.39, 4.49, and 9.05 days, and radii of 1.4, 2.1, and 2.5 \(R_\oplus\), respectively. We also place 95\% confidence upper limits on the masses of 57, 14, and 15 \(M_\oplus\) for TOI-1749b, c, and d, respectively, from transit timing variations. The periods, sizes, and tentative masses of these planets are in line with a scenario in which all three planets initially had a hydrogen envelope on top of a rocky core, and only the envelope of the innermost planet has been stripped away by photoevaporation and/or core-powered mass loss mechanisms. These planets are similar to other planetary trios found around M dwarfs, such as TOI-175b,c,d and TOI-270b,c,d, in the sense that the outer pair has a period ratio within 1\% of 2. Such a characteristic orbital configuration, in which an additional planet is located interior to a near 2:1 period-ratio pair, is relatively rare around FGK dwarfs.
