During bone development, FasL acts not only through the traditional apoptotic mechanism regulating the amount of boneresorbing osteoclasts, but there is also growing evidence about its effect on cell differentiation. Expression of osteoblastic factors was followed in non-differentiated and differentiating primary calvarial cells obtained from FasL-deficient (gld) mice. The gld cells showed decreased expression of the key osteoblastic molecules osteocalcin (Ocn), osteopontin (Opn), and alkaline phosphatase (Alpl) in both groups. Notably, receptor activator of nuclear factor kappa-B ligand (Rankl) was unchanged in nondifferentiated gld vs. wild type (wt) cells but decreased in differentiating gld cells. Osteoprotegerin (Opg) in the gld samples was increased in both groups. Opg vs. Rankl expression levels favored Opg in the case of non-differentiated cells but Rankl in differentiating ones. These results expand information on the involvement of FasL in non-apoptotic cell pathways related to osteoblastogenesis and consequently also osteoclastogenesis and pathologies such as osteoporosis.
The article deals with the problem of determination of basic parameters of unknown lenses, namely their radii of curvature, thicknesses and refractive indices of materials (e.g. optical glasses) from which these lenses are made. Four methods are proposed to obtain these parameters and mathematical relationships are derived that allow to determine the refractive index and Abbe number of lens material based on the measured radius values, the thickness and the position of the focal point or the focal length. and V článku je řešena problematika určení základních parametrů neznámých čoček, a to jejich poloměrů křivosti, tlouštěk a indexů lomu materiálů (např. optických skel), z kterých jsou tyto čočky zhotoveny. Jsou navrženy čtyři metody získání těchto parametrů a jsou odvozeny matematické vztahy, které umožňují určit index lomu a Abbeovo číslo materiálu čoček, a to na základě naměřených hodnot poloměrů křivosti, tloušťky a polohy obrazového ohniska nebo velikosti ohniskové vzdálenosti.