The Effects of Exosomes on the Regeneration of Rat Calvaria

Periodontal disease is a bacterial induced chronic inflammatory condition that occurs in a susceptible host, affecting the teeth, gingiva, periodontal ligament, and alveolar bone. The resultant pathological bone defects often require surgical intervention, with the ultimate goal being regeneration of the periodontium through the application of grafting materials and biologics. Mesenchymal stem cells (MSCs) show great potential in regenerative medicine for their ability to enhance cell proliferation and differentiation, increase angiogenesis, and modulate the immune response. Stem cell-derived by-products, known as exosomes are a specific class of lipid-membrane-bound extracellular vesicles that are proliferative and chemotactic, are able to inhibit cytokine production, and may suppress differentiation of osteoclasts. The aim of this study is to determine if the delivery of exosomes into rat calvarial defects will increase regeneration by reducing the residual defect area and enhancing bone volume. Male Sprague-Dawley rats with bilateral 5mm surgically-created calvarial defects were randomized into groups and treated with low- and high-dose exosome suspensions via a collagen gel matrix or a PBS-soaked collagen control. After 4 weeks, the calvaria were harvested and analyzed via micro computed tomography (micro-CT). Volumetric micro-CT analysis showed that defects treated with high-dose exosomes displayed a trend towards enhanced bone healing. Based on the results of this pilot study, treatment with exosomes could be a promising therapeutic approach for treatment of bone defects

Spectrum of generalized Hodge-Laplace operators on flat tori and round spheres

We consider generalized Hodge-Laplace operators $\alpha d \delta + \beta \delta d$ for $\alpha, \beta > 0$ on $p$-forms on compact Riemannian manifolds. In the case of flat tori and round spheres of different radii, we explicitly calculate the spectrum of these operators. Furthermore, we investigate under which circumstances they are isospectral.Comment: 20 page

The collisional evolution of undifferentiated asteroids and the formation of chondritic meteoroids

Most meteorites are fragments from recent collisions experienced in the asteroid belt. In such a hyper-velocity collision, the smaller collision partner is destroyed, whereas a crater on the asteroid is formed or it is entirely disrupted, too. The present size distribution of the asteroid belt suggests that an asteroid with 100 km radius is encountered $10^{14}$ times during the lifetime of the Solar System by objects larger than 10 cm in radius; the formed craters cover the surface of the asteroid about 100 times. We present a Monte Carlo code that takes into account the statistical bombardment of individual infinitesimally small surface elements, the subsequent compaction of the underlying material, the formation of a crater and a regolith layer. For the entire asteroid, 10,000 individual surface elements are calculated. We compare the ejected material from the calculated craters with the shock stage of meteorites with low petrologic type and find that these most likely stem from smaller parent bodies that do not possess a significant regolith layer. For larger objects, which accrete a regolith layer, a prediction of the thickness depending on the largest visible crater can be made. Additionally, we compare the crater distribution of an object initially 100 km in radius with the shape model of the asteroid (21) Lutetia, assuming it to be initially formed spherical with a radius that is equal to its longest present ellipsoid length. Here, we find the shapes of both objects to show resemblance to each other.Comment: Accepted by Ap

Management of multi-method engineering design research: a case study

There is a need for a research management methodology that will utilise research methods on an individual basis and when combined in a multi-method approach. An agreed methodology would enable rapid progress in achieving agreement on the main issues within engineering design research. Researchers at the University of Glasgow have developed a conceptual management methodology, testing it on three engineering design research projects. This paper describes the methodology and presents results indicating its ability to enable rigorous triangulation of research results obtained via different methods and across different research projects forming the basis of an effective management tool

Sovereign Wealth Funds and Global Justice

Dozens of countries have established Sovereign Wealth Funds in the last decade or so, in the majority of cases employing those funds to manage the large revenues gained from selling resources such as oil and gas on a tide of rapidly rising commodity prices. These funds have raised a series of ethical questions, including just how the money contained in such funds should eventually be spent. This article engages with that question, and specifically seeks to connect debates on SWFs with debates on global justice. Just how good are national claims to the great wealth contained in SWFs in the first place? Using the example of Norway's very large SWF – derived from selling North-Sea petroleum – I show that national claims are at least sometimes very weak, with the implication that the wealth in many such funds is ripe for redistribution in the interests of global justice. I conclude by offering some guidance for how the money contained in such funds could best be spent, with the goal of advancing global justice