Thermodynamic Parameters of Adsorption from Systems Activated Carbon Chlordiazepoxide and Activated Carbon-Diazepam Parámetros termodinámicos de adsorción de los sistemas carbón activado-clordiazepóxido y carbón activado-diazepam

Resumen Se estudian los parámetros termodinámicos de la adsorción de clordiazepóxido y diazepam en seis carbonos activados: Norit B, BDH, Merck, Panreac, M1 y M, en fluido gástrico simulado. Los materiales se caracterizan por: FTIR, pHzpc y adsorción de N 2 a 77 K. La porosidad fue interpretada por las ecuaciones de Dubinin-Radushkevich y BET. Los resultados muestran la relación entre el aumento de la temperatura, las características de cada adsorbente y el comportamiento de estos fármacos. Los valores positivos de todas las entalpías isostéricas de adsorción determinadas a partir de la pendiente de Van 't Hoff (R 2 > 97), indican la naturaleza endotérmica del proceso de adsorción, así como la ∆G < 0 con el incremento de la temperatura. La ∆G < 0 en todos los casos explica el carácter espontáneo del proceso de adsorción. Los valores positivos ∆S dejan claramente que la aleatoriedad se incrementó en la interfaz sólido-solución durante el proceso de adsorción. Palabras clave: carbón activado, adsorción, parámetros termodinámicos. Abstract It is study the thermodynamic parameters of chlordiazepoxide and diazepam drugs adsorbed onto six activated carbons: Norit B, BDH, Merck, Panreac, M1 and M, from simulated gastric fluid at pH 1,2 for 4 h were characterized by FTIR, pH zpc, and adsorption of N 2 to 77 K. The results of porosity were interpreted with the Dubinin-Radushkevich's models and BET' equation. By UV visible spectra residual drugs were monitored. The results show relationship between: increased of temperature, the characteristics of each adsorbent and the behavior of these drugs in acid solution. The positive values of all the isosteric adsorption enthalpies determined from the slope Van't Hoff plot (R 2 > 97), indicate the nature endothermic process of adsorption. The ∆G<0 in all cases explained the spontaneous character of the adsorption process and the positive values of ∆S state clearly that the randomness increased at the solidsolution interface during adsorption process

Multiplex Real-Time PCR Assay Using TaqMan Probes for the Identification of Trypanosoma cruzi DTUs in Biological and Clinical Samples

Background: Trypanosoma cruzi has been classified into six Discrete Typing Units (DTUs), designated as TcI–TcVI. In order to effectively use this standardized nomenclature, a reproducible genotyping strategy is imperative. Several typing schemes have been developed with variable levels of complexity, selectivity and analytical sensitivity. Most of them can be only applied to cultured stocks. In this context, we aimed to develop a multiplex Real-Time PCR method to identify the six T. cruzi DTUs using TaqMan probes (MTq-PCR).Methods/Principal Findings: The MTq-PCR has been evaluated in 39 cultured stocks and 307 biological samples from vectors, reservoirs and patients from different geographical regions and transmission cycles in comparison with a multi-locus conventional PCR algorithm. The MTq-PCR was inclusive for laboratory stocks and natural isolates and sensitive for direct typing of different biological samples from vectors, reservoirs and patients with acute, congenital infection or Chagas reactivation. The first round SL-IR MTq-PCR detected 1 fg DNA/reaction tube of TcI, TcII and TcIII and 1 pg DNA/reaction tube of TcIV, TcV and TcVI reference strains. The MTq-PCR was able to characterize DTUs in 83% of triatomine and 96% of reservoir samples that had been typed by conventional PCR methods. Regarding clinical samples, 100% of those derived from acute infected patients, 62.5% from congenitally infected children and 50% from patients with clinical reactivation could be genotyped. Sensitivity for direct typing of blood samples from chronic Chagas disease patients (32.8% from asymptomatic and 22.2% from symptomatic patients) and mixed infections was lower than that of the conventional PCR algorithm.Conclusions/Significance: Typing is resolved after a single or a second round of Real-Time PCR, depending on the DTU. This format reduces carryover contamination and is amenable to quantification, automation and kit production.This work received financial support from the Ministry of Science and Technology of Argentina [PICT 2011-0207 to AGS] and the National Scientific and Technical Research Council in Argentina (CONICET) [PIP 112 2011-010-0974 to AGS]. Work related to evaluation of biological samples was partially sponsored by the Pan-American Health Organization (PAHO) [Small Grants Program PAHO-TDR]; the Drugs and Neglected Diseases Initiative (DNDi, Geneva, Switzerland), Wellcome Trust (London, United Kingdom), SANOFI-AVENTIS (Buenos Aires, Argentina) and the National Council for Science and Technology in Mexico (CONACYT) [FONSEC 161405 to JMR]