Assessment of the phenotypic effects of Platelet Rich Fibrin on Mesenchymal Stem Cells derived from Minced Pulp

Our aim is to investigate the effects of autologous platelet-rich fibrin (PRF) on Mesenchymal Stem cell derived from Minced Pulp (MP-MSCs). We first developed a mouse model of PRF to study the phenotypic effects of PRF in cultured cells. We obtained PRF from the blood and prepared PRF-enriched culture media. The phenotypic effects of PRF on MP-MSCs were determined by assessing the changes in cell proliferation, differentiation and immunophenotypic profiling. The mRNA levels of ALP, OCN, DMP1 and DSPP were determined by qRT-PCR. It was found that PRF increased the proliferation capacity of MP-MSCs and reduced the cell doubling time. With PRF exposure, the MP-MSCs were able to retain their immunophenotypic characteristics defining them as MSCs, as the cells expressing surface markers CD105, CD146 and CD73 were higher. MP-MSCs were able to undergo osteogenic differentiation in the presence of PRF and the mRNA levels of OCN was significantly increased in the presence of PRF. To assess the odontogenic differentiation of cells in response to PRF, we prepared dentin-slice model in which we cultured MP-MSCs embedded in PRF. Histological sections of the dentin slice model revealed that there was increase in the cellularity of the pulp tissue along the edges of the pulp tissue. Based on our findings, PRF can act as a source of growth factors cell proliferation, migration and differentiation

Manipulating polarized light with a planar slab of Black Phosphorus

Wave polarization contains valuable information for electromagnetic signal processing and the ability to manipulate it can be extremely useful in photonic devices. In this work, we propose designs comprised of one of the emerging and interesting two-dimensional media: Black Phosphorus. Due to substantial in-plane anisotropy, a single slab of Black Phosphorus can be very efficient for manipulating the polarization state of electromagnetic waves. We investigate Black Phosphorus slabs that filter the fields along one direction, or polarization axis rotation, or convert linear polarization to circular. These slabs can be employed as components in numerous mid-IR integrated devices

Explaining foreign firms' approaches to corporate political activity in emerging economies: the effects of resource criticality, product diversification, inter-subsidiary integration, and business ties

Despite the increasing scope for transactional approaches to corporate political activity (CPA) in emerging markets and rising concerns about the use of relational approaches, foreign firms in emerging economies appear to be reluctant to adopt transactional approaches to CPA. Using Resource Dependence theory we argue that criticality of resources, product diversification, integration with other foreign subsidiaries, and business ties may explain why foreign firms adopt a transactional or a relational approach to CPA. We test our hypotheses using a sample of 105 subsidiaries of foreign firms in India. We find that unrelated diversification and close integration with other subsidiaries of their parent firm makes subsidiaries more likely to adopt a transactional approach, whereas local resource criticality and ties to local businesses makes subsidiaries less likely to use a transactional approach to CPA. Our findings enhance our understanding of the factors that determine foreign firms’ choice of approaches to CPA in emerging economies

Peak effect in laser ablated DyBa2Cu3O7-d films at microwave frequencies at subcritical currents

In this paper we report the observation of a peak in the microwave surface resistance (at frequencies ~10GHz) of laser ablated DyBa2Cu3O7-d films in magnetic field ranging from 2 to 9kOe (||c) close to the superconducting transition temperature (Tc(H)). The exact nature of peak is sample dependent but it follows a general behaviour. The peak shifts to lower temperature when the magnetic field is increased. It has strong frequency dependence and the peak is pronounced at frequencies close to the depinning frequency of the flux line lattice. From the observed temperature and field dependence we argue that this peak is associated with the order disorder transition of the flux line lattice close to Tc(H).Comment: 8 pages, 2 pages (accepted for publication in JAP, Intermag symposium proceeding

Modeling of synthesis and flow properties of propylene-diene copolymers

Copolymerization with nonconjugated dienes offers an attractive route for introducing long-chain branching in polypropylene. From a simplified set of rate equations for such copolymerization with a metallocene catalyst, we derive the probabilities of branch formation at different stages of the reaction in a semibatch reactor. Using these probabilities, we generate an ensemble of molecules via a Monte Carlo sampling. The knowledge of the branching topology and segment lengths allows us to compute the flow properties of the resins from computational rheology. We compare our model predictions with existing experimental data, namely the molar mass distribution and small amplitude oscillatory shear response, for a set of resins with varying diene content. The rheology data suggest that the entanglement time Ï.,e depends sensitively and in a well-defined fashion on the diene content

Home institutional imprinting and lobbying expenditure of foreign firms: moderating effects of experience and technological intensity

The issue of whether a firm’s ‘home’ environment influences its nonmarket activities in a ‘host’ country is being increasingly discussed in the international business literature. In this paper, we use institutional and organisational imprinting theories to argue that multinational enterprises (MNEs) founded in countries with stronger regulatory institutions are likely to spend more on lobbying in a host country as compared to MNEs founded in countries with weaker regulatory institutions. We also argue that this effect is moderated by the MNE’s overall experience, its experience within the host country, and its technological intensity. We test our hypotheses using a sample of 378 foreign MNEs (among the largest 500) operating in the United States (U.S.), spanning the 8 year period 2006-2013, and representing 29 home countries. Our results support our hypothesis on the relationship between home-institutional imprinting and overseas lobbying expenditure, as described above. Our results also support our arguments that MNEs’ overall experience and technological intensity reduce the imprinting effect of home institutions on lobbying expenditure; however, our moderating effect of host-country experience on this relationship is not supported

Sikap Keuangan Pada Perusahaan Keluarga: Peran Moderasi Komitmen Keluarga

This study aims to examine the moderating role of family commitment to the influence of the financial knowledge, positive experience with debt suppliers, and   economic  goal  orientation  to  owner- managers’ attitudes toward debt financing in family firms. This study was conducted through a questionnaire survey of 66 owners of family firms, operated in Special Region of Yogyakarta. This study used moderated regression analysis. The results of this study found several important things as follows.  First, the high family commitment toward business strengthened the positive effect of the positive experience with debt suppliers to owner-managers’ attitudes toward debt financing in family firms. Second, the result of the interaction coefficient of economic goal  orientation  and family Commitment was negative and not significant. Third, the result of the interaction coefficient of financial knowledge and family commitment toward business was positive and not significant. This result was opposite to the direction of prediction of the hypothesi

Quantum plasmons with optical-range frequencies in doped few-layer graphene

Although plasmon modes exist in doped graphene, the limited range of doping achieved by gating restricts the plasmon frequencies to a range that does not include the visible and infrared. Here we show, through the use of first-principles calculations, that the high levels of doping achieved by lithium intercalation in bilayer and trilayer graphene shift the plasmon frequencies into the visible range. To obtain physically meaningful results, we introduce a correction of the effect of plasmon interaction across the vacuum separating periodic images of the doped graphene layers, consisting of transparent boundary conditions in the direction perpendicular to the layers; this represents a significant improvement over the exact Coulomb cutoff technique employed in earlier works. The resulting plasmon modes are due to local field effects and the nonlocal response of the material to external electromagnetic fields, requiring a fully quantum mechanical treatment. We describe the features of these quantum plasmons, including the dispersion relation, losses, and field localization. Our findings point to a strategy for fine-tuning the plasmon frequencies in graphene and other two-dimensional materials.MIT/Army Institute for Soldier Nanotechnologies (Contract W911NF-13-D-0001