Diffusion of nitrogen gas through polyethylene based films

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A comparative analysis of old and recent Ag coins by XRF methodology

The investigation of silver coins dated since the first century B.C. up to recent times, coming from different countries in the world, has successfully generated a growing interest among numismatic researchers. The classification of these coins into originals, copies and imitations - according to their provenance and to their Ag content - has been performed by using the X-ray fluorescence (XRF) analysis. The archaeological challenge is to explain the large diversification of these coins, to determine the differences in composition, weight and physical aspects. A non-destructive physical method was employed to study the properties of silver coins (as in this case) allowing a detailed characterization of the analyzed samples. The XRF analysis was applied to the bulk, through an X-ray tube, and to the surface patina, through an electron beam

FDI in Vietnam: An Empirical Study of an Economy in Transition

Vietnam has emerged as an alternative smaller emerging economy market for FDI in the last five years, attracting both domestic market seeking and export oriented FDI. Vietnam continues to attract significant East Asian and OECD investors. This paper analyses the economic determinants of FDI for a smaller Non-BRIC emerging country, undergoing a rapid transition to a market driven economy in a region of great competitiveness among host countries and growing attractiveness to major source countries. The regression models presented in this paper show that while macro-economic variables such as GDP and to a lesser extent labor costs were predictably significant as determinants of FDI in Vietnam, (as they are in developed economies), the loss of value of the Dong, both against the dollar and against SDR, was a significant and negative factor in the regression models. It appears the relationship of the value of the host currency to FDI in newly emerging countries may be different from that of the more developed countries. Tax rates, openness to trade and growth rate were not shown to be significant in this empirical analysis. Perhaps the traditional literature on FDI needs to be re-examined for the unique challenges facing the newly emerging economies such as CIVETS countries

On the large deviations of a class of modulated additive processes

We prove that the large deviation principle holds for a class of processes inspired by semi-Markov additive processes. For the processes we consider, the sojourn times in the phase process need not be independent and identically distributed. Moreover the state selection process need not be independent of the sojourn times. We assume that the phase process takes values in a finite set and that the order in which elements in the set, called states, are visited is selected stochastically. The sojourn times determine how long the phase process spends in a state once it has been selected. The main tool is a representation formula for the sample paths of the empirical laws of the phase process. Then, based on assumed joint large deviation behavior of the state selection and sojourn processes, we prove that the empirical laws of the phase process satisfy a sample path large deviation principle. From this large deviation principle, the large deviations behavior of a class of modulated additive processes is deduced. As an illustration of the utility of the general results, we provide an alternate proof of results for modulated L´evy processes. As a practical application of the results, we calculate the large deviation rate function for a processes that arises as the International Telecommunications Union’s standardized stochastic model of two-way conversational speech

Sample path large deviations principles for poisson shot noise processes, and applications

This paper concerns sample path large deviations for Poisson shot noise processes, and applications in queueing theory. We first show that, under an exponential tail condition, Poisson shot noise processes satisfy a sample path large deviations principle with respect to the topology of pointwise convergence. Under a stronger superexponential tail condition, we extend this result to the topology of uniform convergence. We also give applications of this result to determining the most likely path to overflow in a single server queue, and to finding tail asymptotics for the queue lengths at priority queues

Resonance absorption enhancement in laser-generated plasma ablating Cu treated surfaces

AbstractResonant absorption effects for 1.064 µm infrared laser pulse radiations are investigated by using different techniques producing micrometric surface structures with dimensions comparable to the wavelength value. The laser absorption is controlled through measurement of the Cu ion acceleration using time-of-flight approach. Surface treatments include low energy laser etching in air, deposition of microspheres obtained ablating Cu targets in water, pulse laser deposition of microstructures precursor of thin homogeneous film, chemical etching with HNO3 acid, Ar+ ion sputtering and rolling burnishing surface of thin Cu foils. Results indicate that the best resonance effect is obtained with the rolling burnishing, ion sputtering and microsphere deposition processes which enhance the Cu ion energy and the yield emission

HCV derived from sera of HCV-infected patients induces pro-fibrotic effects in human primary fibroblasts by activating GLI2

Hepatitis C virus (HCV) infection is a leading cause of liver fibrosis, especially in developing countries. The process is characterized by the excess accumulation of ECM that may lead, over time, to hepatic cirrhosis, liver failure and also to hepatocarcinoma. The direct role of HCV in promoting fibroblasts trans-differentiation into myofibroblasts, the major fibrogenic cells, has not been fully clarified. In this study, we found that HCV derived from HCV-infected patients infected and directly induced the trans-differentiation of human primary fibroblasts into myofibroblasts, promoting fibrogenesis. This effect correlated with the activation of GLI2, one of the targets of Hedgehog signaling pathway previously reported to be involved in myofibroblast generation. Moreover, GLI2 activation by HCV correlated with a reduction of autophagy in fibroblasts, that may further promoted fibrosis. GLI2 inhibition by Gant 61 counteracted the pro-fibrotic effects and autophagy inhibition mediated by HCV, suggesting that targeting HH/GLI2 pathway might represent a promising strategy to reduce the HCV-induced fibrosis

Dbl oncogene expression in MCF-10 A epithelial cells disrupts mammary acinar architecture, induces EMT and angiogenic factor secretion.

The proteins of the Dbl family are guanine nucleotide exchange factors (GEFs) of Rho GTPases and are known to be involved in cell growth regulation. Alterations of the normal function of these proteins lead to pathological processes such as developmental disorders, neoplastic transformation, and tumor metastasis. We have previously demonstrated that expression of Dbl oncogene in lens epithelial cells modulates genes encoding proteins involved in epithelial-mesenchymal-transition (EMT) and induces angiogenesis in the lens. Our present study was undertaken to investigate the role of Dbl oncogene in epithelial cells transformation, providing new insights into carcinoma progression. To assess how Dbl oncogene can modulate EMT, cell migration, morphogenesis, and expression of pro-apoptotic and angiogenic factors we utilized bi- and three-dimensional cultures of MCF-10░A cells. We show that upon Dbl expression MCF-10░A cells undergo EMT. In addition, we found that Dbl overexpression sustain