Coupling constants of D∗DsKD^*D_sK and Ds∗DKD_s^*DK processes

We calculate the coupling constants of $D^*D_sK$ and $D_s^*DK$ vertices using the QCD sum rules technique. We compare results obtained in the limit of SU(4) symmetry and found that the symmetry is broken on the order of 40%.Comment: 4 pages, 3 ps figures. Talk presented in the 18 Workshop on Hadron Interactions, IFUSP, Sao Paulo, Brazil, may 22-24 of 200

A QCD sum rules calculation of the J/ψDs∗DsJ/\psi D_s^* D_s strong coupling constant

In this work, we calculate the form factors and the coupling constant of the strange-charmed vertex $J/\psi D_s^* D_s$ in the framework of the QCD sum rules by studying their three-point correlation functions. All the possible off-shell cases are considered, $D_s$, $D_s^*$ and $J/\psi$, resulting in three different form factors. These form factors are extrapolated to the pole of their respective off-shell mesons, giving the same coupling constant for the process. Our final result for the $J/\psi D_s^* D_s$ coupling constant is $g_{J/\psi D^*_s D_s} = 4.30^{+0.42}_{-0.37}\text{GeV}^{-1}$.Comment: 17 pages, 4 figure

Temperature dependence of the first order Raman scattering in thin films of mc-Si:H

The temperature effect on microcrystalline silicon (mc-Si:H) films produced by R.F. magnetron sputtering has been studied by Raman spectroscopy. The thermal behaviour of mc-Si:H films and crystalline silicon is compared and interpreted on the basis of anharmonic effects. We have studied the first order Raman spectra of our films for several Ar+ laser powers. Our results show a blue shift and a broadening of the Raman spectra with increasing the laser power. This effect is not due to structural changes since it is reproducible. The sample temperature has been calculated according to the well known relation between Stokes and anti-Stokes components. Our results show that the temperature effect is stronger in mc-Si:H than in crystalline silicon. This difference can be attributed to the size of the microcrystals, which are imbedded in a amorphous matrix surrounded by a third phase called grain boundary

Influence of surfactant and processing conditions in the stability of oil-in-water nanoemulsions

This work evaluates the influence of the type of surfactant (Tween 20, SDS and DTAB) and processing conditions on the stability of oil-in-water nanoemulsions, measured in terms of hydrodynamic diameter (Hd), polydispersity index (PdI) and zeta potential (Zp). Nanoemulsions were prepared using high-pressure homogenization based on a 24 level factorial design. Results show that processing parameters such as homogenization pressure, surfactant concentrations and oil:water ratio significantly affected the values of Hd and PdI of nanoemulsions. The value of Hd of anionic nanoemulsions decreased (from 177 to 128 nm) with the increase of the homogenization pressure. The increase in the surfactant concentration and the decrease of the oil:water ratio lead to a decrease of Hd for the cationic nanoemulsions (from 198 to 135 nm). The increase of the oil:water ratio lead to a decrease of Hd for the non-ionic nanoemulsions (from 341 to 171 nm); this is contrary to the usual assumption that higher content in oil results in higher values of Hd. Those nanoemulsions showed a good kinetic stability (evaluated after centrifugation, heatingcooling cycles and thermal stress) upon measuring the Hd during 28 and 35 days of storage, without visual evidence of creaming and phase separation. After one year of storage the nanoemulsions produced with the anionic surfactant remained kinetically stable, without visual evidence of creaming and/or phase separation.Helder D. Silva, and Miguel A. Cerqueira (SFRH/BD/81288/2011, and SFRH/BPD/72753/2010, respectively) are the recipients of a fellowship from the Fundacao para a Ciencia e Tecnologia (FCT, Portugal). The authors would like to acknowledge to Francesco Donsi and Giovanna Ferrari from Department of Industrial Engineering, University of Salerno for helping in the viscosity and density measurements and to Rui Fernandes from IBMC, University of Porto for assistance in taking the TEM pictures. The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013 and the project "BioInd-Biotechnology and Bioengineering for improved Industrial and Agro-Food processes", REF.NORTE-07-0124- FEDER-000028, co-funded by the Programa Operacional Regional do Norte (ON.2 - 0 Novo Norte), QREN, FEDER. We also thank to the European Commission: BIOCAPS (316265, FP7/REGPOT-2012-2013.1). The support of EU Cost Action FA1001 is gratefully acknowledged. Also the authors acknowledge Stepan for providing the Neobee 1053 oil

Influence of α-tocopherol on physicochemical properties of chitosan-based films

tosan has been exploited as a material for the development of edible films, and additionally can be used as a carrier of functional compounds such as α-tocopherol. The aim of this work was to evaluate the effects of the incorporation of α-tocopherol in chitosan-based films. FTIR and thermal analyses were performed and showed that the incorporation of α-tocopherol affects the chemical structure of chitosan-based films with the establishment of new chemical bonds and the decrease of crystallinity. Results also showed that the increase of α-tocopherol concentration promotes a decrease of water content (from 12.6 to 11.4%) of the films. The addition of α-tocopherol to chitosan films leads to a significant reduction (p < 0.05) of tensile strength from 34.06 to 16.24 MPa, and elongation-at-break from 53.84 to 23.12%. Film opacity values (ranging from 4.74 to 7.83%) increased when α-tocopherol was incorporated into the film. Antioxidant capacity of chitosan-based films was evaluated and was enhanced when α-tocopherol was present in the film matrix. Results showed that α-tocopherol can be successfully added to the chitosan films enhancing the final quality and shelf-life extension of food products.J. T. Martins and M. A. Cerqueira gratefully acknowledge the Fundacao para a Ciencia e Tecnologia (FCT, Portugal) for their fellowships (SFRH/BD/32566/2006 and SFRH/BPD/72753/2010, respectively)

Bio-based nanofilms/coatings for food applications

Edible packaging for food is one of the areas where developments are being made based on nanotechnological solutions, e.g. through the development of edible nanofilms and nanocoatings, in particular under the form of edible nanolaminates. Polysaccharides, proteins and/or lipids are used due their GRAS statute. Polysaccharide- and protein-based films/coatings provide good barriers to O2 and CO2, but are very permeable to water vapor; in turn, lipid-based films/coatings provide excellent barriers to water vapor but have a limited resistance to other gases and have low mechanical resistance. The use of successive nano-layers will provide better physical stability in aggressive environments, better chemical stability to active compounds which may be incorporated into these structures; and improved control of the release rates of such compounds. The application of this technology can be used for the enhancement of food safety, for the encapsulation of functional food ingredients, and in systems providing the integration of sensing, localization, reporting and remote control of food products. At the current state of knowledge, many of these applications may be difficult to adopt commercially due the difficult to be implement at an industrial scale. Moreover, the effects of nanotechnological systems in the human body are still unclear. This means that using nanotechnological applications in foods must be justified essentially by their advantages, which must be clearly perceived by the consumer. Not doing so will undermine consumers’ trust on this emerging technology, eventually hindering its success in future applications