Thermodynamic study of racemic ibuprofen separation by liquid chromatography using cellulose-based stationary phase

Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID), also known for its significant antipyretic and analgesic properties. This chiral drug is commercialized in racemic form; however, only S-(+)-ibuprofen has clinical activities. In this paper the effect of temperature change (from 288.15 to 308.15 K) on the ibuprofen resolution was studied. A column ( mm) packed with tris(3,5-dimethylphenylcarbamate) was used to obtain the thermodynamic parameters, such as enthalpy change (), entropy change (), variation enthalpy change (), variation entropy change (), and isoenantioselective temperature (). The mobile phase was a combination of hexane (99%), isopropyl alcohol (1%), and TFA (0.1%), as an additive. The conditions led to a selectivity of 1.20 and resolution of 4.55. The first peak, R-(−)-ibuprofen, presented an enthalpy change of 7.21 kJ/mol and entropy change of 42.88 kJ/K·mol; the last peak, S-(+)-ibuprofen, has an enthalpy change of 8.76 kJ/mol and 49.40 kJ/K·mol of entropy change2016CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQsem informaçã

Tribocorrosion behavior of beta titanium biomedical alloys in phosphate buffer saline solution

[EN] The tribo-electrochemical behavior of different β titanium alloys for biomedical applications sintered by powder metallurgy has been investigated. Different mechanical, electrochemical and optical techniques were used to study the influence of the chemical composition, Sn content, and the electrochemical conditions on the tribocorrosion behavior of those alloys Ti30NbxSn alloys (where x is the weight percentage of Sn content, 2% and 4%). Sn content increases the active and passive dissolution rate of the titanium alloys, thus increasing the mechanically activated corrosion under tribocorrosion conditions. It also increases the mechanical wear of the alloy. Prevailing electrochemical conditions between 1 and 2 V influences the wear accelerated corrosion by increasing it with the applied potential and slightly increases the mechanical wear of Ti30Nb4Sn. Wear accelerated corrosion can be predicted by existing models as a function of electrochemical and mechanical parameters of the titanium alloys.The authors would like to thank the Ministerio de Ciencia e Innovacion of the Spanish government for the financial support under the project MAT2011-22481.Guiñón Pina, V.; Dalmau, A.; Devesa, F.; Amigó Borrás, V.; Igual Muñoz, AN. (2015). Tribocorrosion behavior of beta titanium biomedical alloys in phosphate buffer saline solution. Journal of the Mechanical Behavior of Biomedical Materials. 46:59-68. https://doi.org/10.1016/j.jmbbm.2015.02.016S59684

Neutrophil-specific deletion of the CARD9 gene expression regulator suppresses autoantibody-induced inflammation in vivo

Neutrophils are terminally differentiated cells with limited transcriptional activity. The biological function of their gene expression changes is poorly understood. CARD9 regulates transcription during antifungal immunity but its role in sterile inflammation is unclear. Here we show that neutrophil CARD9 mediates pro-inflammatory chemokine/cytokine but not lipid mediator release during non-infectious inflammation. Genetic deficiency of CARD9 suppresses autoantibody-induced arthritis and dermatitis in mice. Neutrophil-specific deletion of CARD9 is sufficient to induce that phenotype. Card9(-/-) neutrophils show defective immune complex-induced gene expression changes and pro-inflammatory chemokine/cytokine release but normal LTB4 production and other short-term responses. In vivo deletion of CARD9 reduces tissue levels of pro-inflammatory chemokines and cytokines but not LTB4. The CARD9-mediated signalling pathway involves Src-family kinases, Syk, PLCγ2, Bcl10/Malt1 and NFκB. Collectively, CARD9-mediated gene expression changes within neutrophils play important roles during non-infectious inflammation in vivo and CARD9 acts as a divergence point between chemokine/cytokine and lipid mediator release

Tumor-induced stromal reprogramming drives lymph node transformation.

Lymph node (LN) stromal cells, particularly fibroblastic reticular cells (FRCs), provide critical structural support and regulate immunity, tolerance and the transport properties of LNs. For many tumors, metastasis to the LNs is predictive of poor prognosis. However, the stromal contribution to the evolving microenvironment of tumor-draining LNs (TDLNs) remains poorly understood. Here we found that FRCs specifically of TDLNs proliferated in response to tumor-derived cues and that the network they formed was remodeled. Comparative transcriptional analysis of FRCs from non-draining LNs and TDLNs demonstrated reprogramming of key pathways, including matrix remodeling, chemokine and/or cytokine signaling, and immunological functions such as the recruitment, migration and activation of leukocytes. In particular, downregulation of the expression of FRC-derived chemokine CCL21 and cytokine IL-7 were accompanied by altered composition and aberrant localization of immune-cell populations. Our data indicate that following exposure to tumor-derived factors, the stroma of TDLNs adapts on multiple levels to exhibit features typically associated with immunosuppression.This research was supported by the CIMR Flow Cytometry Core Facility. We wish to thank all FCCF staff members for their advice and support in flow cytometry and cell sorting applications. Work was supported by Medical Research Council funding. BAH is supported by the Royal Society (University Research Fellowship).This is the author accepted manuscript

Stochastic analysis of aromatic amino acids chromatographic pulses

The amino acids L-phenylalanine (Phe), L-tyrosine (Tyr) and L-Tryptophan (Trp) play an important role in the human body. L-Phenylalanine and L-tyrosine are precursors of several neurotransmitters, while Trp has been indicated as an aid for schizophrenic patients. These amino acids can be separated by ion exchange chromatography, and, usually, its description adopts differential mass balance equations for the stationary and mobile phases. The stochastic model can be an alternative to the traditional approach. Normally based on a microscopic view of chromatography, the random migration of a molecule is considered from a probabilistic aspect to describe the distribution function of the solute in the elution process. In the present work, the stochastic model in a fixed-bed adsorption has been studied by another point of view. The response of the adsorption column to the injection is measured as concentration vs. time at the exit of the column. Based on this, chromatographic pulses of aromatic amino acids are analyzed by Kolmogorov entropy theory. The rate of generation of information about concentration at the column exit can be identified with certain probability density function (PDF), and with a degree of the rate of generation of information of the system, characterized by the Kolmogorov entropy. The system tested is a fixed-bed, packed with poly-4-vinylpyridine cross-linked with divinyl benzene, and dilute aqueous solutions of NaCl and the aromatic amino acids Phe, Tyr, and Trp in two liquid flow rates. This work shows that is possible to reconstruct the solute effluent history using an appropriate PDF. In order to find the PDF that provides the best description of the experimental data, fourteen functions where fitted by the Least Squares Method. According to Kolmogorov-Smirnov test, Normal, Log- Normal, Logistic, Gamma, Pearson III and Beta models provided a satisfactory fit, and the dimensionless Kolmogorov entropy parameter depends on the affinity between solute and adsorbent, and the flow rate of carrier stream, implying its relation with dispersion phenomena and the nature of solute and adsorbent5712071212CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESsem informação01/08101-