Designing Biomimetic Implant Surfaces to Promote Osseointegration under Osteoporotic Conditions by Revitalizing Mechanisms Coupling Bone Resorption to Formation

In cases of compromised bone remodeling like osteoporosis, insufficient osseointegration occurs and results in implant failure. Implant retention relies on proper secondary fixation, which is developed during bone remodeling. This process is disrupted in metastatic bone diseases like osteoporosis. Osteoporosis is characterized low bone mass and bone strength resulting from either accelerated osteoclast-mediated bone resorption or impaired osteoblast-mediated bone formation. These two processes are not independent phenomena. In fact, osteoporosis can be viewed as a breakdown of the cellular communication connecting bone resorption to bone formation. Because bone remodeling occurs at temporally generated specific anatomical sites and at different times, local regulators that control cross-talk among the cells of the BRU are important. Previous studies show Ti implant surface characteristics like roughness, hydrophilicity, and chemistry influence the osteoblastic differentiation of human MSCs and maturation of OBs. Furthermore, microstructured Ti surfaces modulate the production of factors shown to be important in the reciprocal communication necessary for the maintenance of healthy bone remodeling. Semaphorin signaling proteins are known to couple the communication of osteoblasts to osteoclasts and are capable of stimulating bone formation or bone resorption depending on certain cues. Implant surface properties can be optimized to exploit these effects to favor rapid osseointegration in patients with osteoporosis

The Globular Cluster Luminosity Function and Specific Frequency in Dwarf Elliptical Galaxies

The globular cluster luminosity function, specific globular cluster frequency, S_N, specific globular cluster mass, T_MP, and globular cluster mass fraction in dwarf elliptical galaxies are explored using the full 69 galaxy sample of the HST WFPC2 Dwarf Elliptical Galaxy Snapshot Survey. The GCLFs of the dEs are well-represented with a t_5 function with a peak at M_{V,Z}^0(dE,HST) = -7.3 +/- 0.1. This is ~0.3 magnitudes fainter than the GCLF peaks in giant spiral and elliptical galaxies, but the results are consistent within the uncertainties. The bright-end slope of the luminosity distribution has a power-law form with slope alpha = -1.9 +/- 0.1. The trend of increasing S_N or T_MP with decreasing host galaxy luminosity is confirmed. The mean value for T_MP in dE,N galaxies is about a factor of two higher than the mean value for non-nucleated galaxies and the distributions of T_MP in dE,N and dE,noN galaxies are statistically different. These data are combined with results from the literature for a wide range of galaxy types and environments. At low host galaxy masses the distribution of T_MP for dE,noN and dI galaxies are similar. This supports the idea that one pathway for forming dE,noN galaxies is by the stripping of dIs. The formation of nuclei and the larger values of T_MP in dE,N galaxies may be due to higher star formation rates and star cluster formation efficiencies due to interactions in galaxy cluster environments.Comment: 53 pages, 13 figures, 12 tables, accepted by the Astrophysical Journa

Sterility as a ground for nullifying the marriage: Can Venter and Van Niekerk be reconciled?

From text: For a marriage to be valid, all the statutory and common law requirements must be satisfied. In a case where all the requirements of marriage are prima facie present, but one or more of the requirements is defective because of, relevant to this work, material misrepresentation, such marriage is regarded as voidable. With material misrepresentation, the question is whether a person in the position of the innocent party would not have entered into the marriage had s/he been aware of the true nature of things. Of course, not every aspect of misrepresentation can lead to material misrepresentation; the misrepresentation must relate to the material aspect of marriage, and those include serious diseases, impotence and others, but this paper deals only with sterility. Sterility has thus been defined as infertility, that is, “the ability to have sexual intercourse but unable to procreate children”