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Acosta-Esquijarosa J.,Higher Polytechnic Institute Jose A Echeverria | Alvarez-Reyes A.,Center for Biomolecular Chemistry | Gonzalez-Lavaut J.A.,Center for Biomolecular Chemistry
Emirates Journal of Food and Agriculture | Year: 2011

The knowledge of the relationship between the equilibrium moisture content and the water activity is very important in order to describe the drying process and the effect of humidity on safe storage. In this work the water sorption isotherms of the Erythroxylum minutifolium Griseb leaves at 30 and 40°C were determined over relative humidity ranging from 55 to 85%. The sorption capacity of natural product increased with the increase of water activity. The moisture sorption isotherms showed that the equilibrium moisture decreases with increase of temperature. Six models were used to fit the experimental curves of equilibrium humidity. The parameters of each equation were determined by non-linear regression analysis. The isosteric heat of moisture sorption was calculated using the Claussius-Clapeyron equation.

Acosta-Esquijarosa J.,Higher Polytechnic Institute Jose A Echeverria | Alvarez-Reyes A.,Center for Biomolecular Chemistry | Gonzalez-Lavaut J.A.,Center for Biomolecular Chemistry
Emirates Journal of Food and Agriculture | Year: 2011

In the present investigation, the drying kinetic of Erythroxylum minutifolium Griseb leaves was studied. The milling leaves were dried in a tray dryer at selected temperatures (50-70°C), air flow speed (2-4 m/s) and bed depth (10-20 cm). The sorption isotherm of the fresh product was mathematically described by the Guggenheim, Anderson and de Boer (GAB) model, giving as a result monolayer moisture of 0.23 g /g d.b. The results indicated that the drying process takes place in the falling rate period and both the bed depth and the temperature of air are the parameters with most influence in the drying of E. minutifolium leaves. The diffusivity coefficient increased with the temperature from 4.30-5.56 10 -07 m 2/s, for a range of temperatures between 50 and 70°C, with an estimated activation energy of 204.13 kJ/mol. Three equations were used for modelling of drying kinetic of leaves. The Page's model was found the best to fit of the data, showing that this equation correctly simulates the E. minutifolium leaves dehydration process and represents an excellent tool for estimating its drying time.

Balbin Y.V.,Center for Biomolecular Chemistry | Rodriguez M.C.,Center for Biomolecular Chemistry | Bencomo V.V.,Center for Biomolecular Chemistry
Carbohydrate Chemistry | Year: 2014

General advances in the glycosciences have increased our knowledge of the structure and function of carbohydrates on the surface of pathogenic bacteria. Synthetic oligosaccharides are invaluable to glycoimmunology for the definition of the epitopes associated with recognition and protection. Almost ten years ago Quimi-Hib, the first vaccine produced based on a synthetic oligosaccharide, was licensed in Cuba for use in infants. Since then, more than 34 million doses were produced and used in several countries, proving that the synthetic approach is economically feasible. Several other synthetic oligosaccharides are in the pipeline for diseases which currently do or do not have efficient vaccines available. The present review will outline the most salient of those examples. © The Royal Society of Chemistry 2014.

Dotres C.P.,University of Habana | Puga R.,University of Habana | Ricardo Y.,University of Habana | Brono C.R.,University of Habana | And 30 more authors.
Vaccine | Year: 2014

A new heptavalent conjugate vaccine (PCV7-TT) is under development in Cuba. PCV7-TT contains 2. μg of serotypes 1, 5, 14, 18C, 19F, 23F and 4. μg of 6B, each one conjugated to tetanus toxoid (TT). This vaccine was designed with the serotypes that cause most invasive pneumococcal diseases (IPD) worldwide. In the present study, we investigated the safety and explored the immunogenicity of PCV7-TT during a controlled, randomized and double blind clinical trial phase I in 4-5-year-old children. PCV7-TT was well tolerated and as safe as Synflorix used as control vaccine. Following a single-dose vaccination, all individual serotypes included in PCV7-TT induced statistically significant increase of IgG GMC and OPA GMT. These are the first clinical results of PCV7-TT in children and they pave the way toward next clinical trials in children and infants. This clinical trial was published in the Cuban Public Register of Clinical Trials with code RPCEC00000173. © 2014 Elsevier Ltd.

Chang J.,Center for Biomolecular Chemistry | Serrano Y.,Center for Biomolecular Chemistry | Garrido R.,Center for Biomolecular Chemistry | Rodriguez L.M.,Center for Biomolecular Chemistry | And 6 more authors.
Vaccine | Year: 2012

Capsular polysaccharides are important virulence factors of Streptococcus pneumoniae. The polysaccharide has been used as a component of vaccines against pneumococcal diseases either as plain polysaccharide or better conjugated to a protein. The last one is the vaccine of choice to target child protection. The immune responses depend on several polysaccharide physicochemical properties that can be affected during either purification or modification in the case of conjugate vaccines. In serotype 18C, the repeating unit has a complex structure having a branched pentasaccharide with two apparently labile subtituents: glycerol-phosphate and O-acetyl group. The loss of these groups may potentially reduce the ability of the 18C polysaccharide to induce the desired immune response. Therefore, the relationship of both groups with the antigenicity and immunogenicity of 18C capsular polysaccharide is explored. It is shown that glycerol-phosphate must be preserved for conserving adequate antigenicity of the 18C capsular polysaccharide. At the same time, it was proved that O-acetyl groups do not play any role for the antigenicity and immunogenicity. © 2012 Elsevier Ltd.

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