Measurement and PC-SAFT modeling of solid-liquid equilibrium of deep eutectic solvents of quaternary ammonium chlorides and carboxylic acids

In this study the solid-liquid equilibria (SLE) of 15 binary mixtures composed of one of three different symmetrical quaternary ammonium chlorides and one of five different fatty acids were measured. The experimental data obtained showed extreme negative deviations to ideality causing large melting-temperature depressions (up to 300 K) that are characteristic for deep eutectic systems. The experimental data revealed that cross-interactions between quaternary ammonium salt and fatty acid increase with increasing alkyl chain length of the quaternary ammonium chloride and with increasing chain length of the carboxylic acid. The pronounced decrease of melting temperatures in these deep eutectic systems is mainly caused by strong hydrogen-bonding interactions, and thermodynamic modeling required an approach that takes hydrogen bonding into account. Thus, the measured phase diagrams were modeled with perturbed-chain statistical associating fluid theory based on the classical molecular homonuclear approach. The model showed very good agreement with the experimental data using a semi-predictive modeling approach, in which binary interaction parameters between quaternary ammonium chloride and carboxylic acid correlated with chain length of the components. This supports the experimental findings on the phase behavior and interactions present in these systems and it allows estimating eutectic points of such highly non-ideal mixtures.This work was developed in the scope of the project CICECO e Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (Ref. FCT UID/CTM/50011/2013) and LSRE-LCM, POCI-01-0145- FEDER-006984jUID/EQU/50020/2013, financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. M.A.R.M acknowledges FCT for her PhD grant (SFRH/BD/87084/2012). FCT is also acknowledged for funding the project DeepBiorefinery (PTDC/AGRTEC/ 1191/2014). P.V.A.P., G.J.M., M.D.H. and E.A.C.B thank the national funding agencies CNPq (National Council for Scientific and Technological Development) (305870/2014-9, 309780/2014, 406856/2013-3), FAPESP (Research Support Foundation of the State of S~ao Paulo) (2014/21252-0, 2016/08566-1), FAEPEX/UNICAMP (Fund for Research, Teaching, and Extension) (0125/16) and CAPES (Coordination of Improvement of Higher Level Personnel) for financial support and scholarships. E.A.C thanks Erasmusþ program of the European Union for co-funding.info:eu-repo/semantics/publishedVersio

A pre formulation study of tetracaine loaded in optimized nanostructured lipid carriers

Tetracaine TTC is a local anesthetic broadly used for topical and spinal blockade, despite its systemic toxicity. Encapsulation in nanostructured lipid carriers NLC may prolong TTC delivery at the site of injection, reducing such toxicity. This work reports the development of NLC loading 4 TTC. Structural properties and encapsulation efficiency EE amp; 8201; gt; amp; 8201;63 guided the selection of three pre formulations of different lipid composition, through a 23 factorial design of experiments DOE . DLS and TEM analyses revealed average sizes 193 220 nm , polydispersity lt; amp; 8201;0.2 , zeta potential amp; 8722; amp; 8201;21.8 to amp; 8722; amp; 8201;30.1 mV and spherical shape of the nanoparticles, while FTIR ATR, NTA, DSC, XRD and SANS provided details on their structure and physicochemical stability over time. Interestingly, one optimized pre formulation CP TRANS TTC showed phase separation after 4 months, as predicted by Raman imaging that detected lack of miscibility between its solid cetyl palmitate and liquid Transcutol lipids. SANS analyses identified lamellar arrangements inside such nanoparticles, the thickness of the lamellae been decreased by TTC. As a result of this combined approach DOE and biophysical techniques two optimized pre formulations were rationally selected, both with great potential as drug delivery systems, extending the release of the anesthetic gt; amp; 8201;48 h and reducing TTC cytotoxicity against Balb c 3T3 cell

Deep inelastic scattering of baryons in a modified soft wall model

We calculate the structure functions for unpolarized deep inelastic scattering of baryons using an AdS/QCD soft wall model that considers a dressed mass for the bulk fermionic fields. Considering the regime of large Bjorken parameter x, we compare the results for the proton structure function $F_2$ with experimental results.Comment: We improved the comparison with experimental data and included more references, version to appear in EPJ

Anomalous dimensions and scalar glueball spectroscopy in AdS/QCD

An extended version of the AdS/QCD Soft-Wall model that incorporates QCD-like anomalous contributions to the dimensions of gauge theory operators is proposed. This exploratory approach leads to a relation between scalar glueball masses and beta functions. Using this relation, properties of the glueball mass spectroscopy that emerge from phenomenological beta functions proposed in the literature are investigated. The reverse problem is also considered: starting from a linear Regge trajectory which fits the lattice glueball masses, beta functions with different asymptotic infrared behaviours are found. Remarkably, some of them present a fixed point at finite coupling.Comment: 27 pages. V4: Expanded text with more discussions. Results unchanged. To appear in EPJ

Light-Front Holography, Light-Front Wavefunctions, and Novel QCD Phenomena

Light-Front Holography, a remarkable feature of the AdS/CFT correspondence, maps amplitudes in anti-de Sitter (AdS) space to frame-independent light-front wavefunctions of hadrons in physical space-time. The model leads to an effective confining light-front QCD Hamiltonian and a single-variable light-front Schrodinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is identified with a Lorentz-invariant coordinate zeta which measures the separation of the constituents within a hadron at equal light-front time and determines the off-shell dynamics of the bound-state wavefunctions and the fall-off in the invariant mass of the constituents. The soft-wall holographic model, modified by a positive-sign dilaton metric, leads to a remarkable one-parameter description of nonperturbative hadron dynamics -- a semi-classical frame-independent first approximation to the spectra and light-front wavefunctions of meson and baryons. The model predicts a Regge spectrum of linear trajectories with the same slope in the leading orbital angular momentum L of hadrons and the radial quantum number n. The hadron eigensolutions projected on the free Fock basis provides the complete set of valence and non-valence light-front Fock state wavefunctions which describe the hadron's momentum and spin distributions needed to compute measures of hadron structure at the quark and gluon level. The effective confining potential also creates quark- antiquark pairs. The AdS/QCD model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method to systematically include the QCD interaction terms. A new perspective on quark and gluon condensates is also presented.Comment: Presented at LIGHTCONE 2011, 23 - 27 May, 2011, Dallas, T