Zein microspheres: preparation and evaluation as a carrier for vaccine delivery.

A method for the preparation of smooth and spherical microspheres of the hydrophobic corn protein, zein, by a phase separation method, is reported in this thesis. Solubility studies on zein as well as amino acid and peptide composition analyses, together with studies on the formulation process were carried out to comprehend the mechanisms of zein microsphere formation. Microspheres were characterised in terms of guest molecule loading, size, charge, morphology, and composition. Ovalbumin, as a model protein/antigen guest, was incorporated into the zein microspheres during microsphere formation at different experimental loadings, and its in vitro release was examined in phosphate buffer at 37 °C. Microsphere degradation studies as a function of medium pH and in the presence of enzymes were also performed in vitro to understand the release of the guest molecule. Zein microspheres were found to be extremely resistant to degradation in the absence of enzymes, which was reflected in negligible release of ovalbumin. Finally, zein microspheres (both blank and ovalbumin-loaded) were administered orally, intramuscularly, rectally, and vaginally to investigate whether a zein microparticulate carrier system was capable to induce an enhanced immune response to the model antigen. In these studies, adjuvanticity of zein microspheres could not be proved due to the antigenicity of the zein protein

Investigating genotype by environment and QTL by environment interactions for developmental traits in potato

Wageningen UR Plant Breeding has carried out studies on different developmental processes of potato making use of a segregating population evaluated in the field under different environmental conditions and day length regimens. The field trials have included the evaluation of below and above ground traits during different stages of the growing season. Extensive molecular data is available on this experimental potato population as well. Thus, this population provided an excellent opportunity for genetic studies based on information previously generated in research projects making use of statistical methods and models to integrate the different data sets and developmental stages. We have been able to get insights about the correlation between above and below ground traits over different environments, to identify stable QTLs under different multi-location and multi-year field trials, as well as QTLxE interactions. Valuable information have been generated regarding stability of developmental traits and common genetic factors influencing them. In this sense our study brings new insights related with potato development and adaptation to different environmental conditions.</p

Development of novel building insulation materials, incorporating cellulose and biobased additives

Cellulose insulation is manufactured from recycled paper fibres, treated with mineral additives acting as flame retardants and antifungals. Its consistency is similar to cotton wool. The fibres are sold in bulk to be blown into the walls and attics. Its thermal conductivity is around 0.04 W/m.K, which is comparable to glass wool, but it is made with recycled materials and has much lower embodied energy levels. It can be either blown dry or sprayed with water. The wet spray method for cellulose insulation has several benefits compared to the dry process. Since the cellulose fibres become rigid after drying, it prevents the compaction of the material thus avoiding thermal bridges in the building envelope. However, the time to reach the dry state may be very long and variable depending on the dosage used and the environmental conditions of application. There are many bio-based additives that can contribute to the reduction of this period and improve the cohesion of the material. This research project aims to find the optimal additive for this application while retaining the favourable properties of the insulating material. Two cellulose types have been characterized with regards to the properties of the fibres to determine their performance with water. Both samples showed differences in chemical composition, grain size, and morphology. The values of water retention, water adsorption isotherms and the proportions of free and bound water have been factors which have shown an influence on the drying of the insulation. Density, compressive strength, and thermal conductivity increased with moisture dosage. A minimum of 14 kPa for the compression module was defined as the resistance threshold to avoid settling. These properties were compared with those of the cellulose insulation compacted to dryness and the results showed the strong influence of the stiffening and pore closing process upon drying, on these properties. Potential bio-based additives were classified and characterized with regards between concentration, viscosity, and adhesive strength. A relationship between these parameters was established. Most showed Newtonian behaviour at low concentrations, with some non- Newtonian concentrations having a pumpable viscosity. Unfortunately several additives which showed good adhesive properties were too viscous and vice versa. A range of surfactants were also considered. Sprayable formulations were characterized with respect to their drying time, compressive strength and thermal conductivity. Additives which have shown positive contributions drying are the lignosulfonate and the cationic surfactant CTAB. The influence of these additives on drying, with varying weather, liquid dosage and thickness of insulation was defined with a numerical model through the WUFI software. Optimal conditions in which the lignosulfonate additive is more effective have been defined. A first assessment of the performance of new formulation in terms of fire and mould was made and indications for the continuation of the study of the material were formalized

Un modelo distribuido para calcular descriptores locales de malla 3D basados en k-rings

In order to facilitate 3D object processing, it is common to use high-level representations such as local descriptors that are usually computed using defined neighborhoods. K-rings, a technique to define them, is widely used by several methods. In this work, we propose a model for the distributed computation of local descriptors over 3D triangular meshes, using the concept of k-rings. In our experiments, we measure the performance of our model on huge meshes, evaluating the speedup, the scalability, and the descriptor computation time. We show the optimal configuration of our model for the cluster we implemented and the linear growth of computation time regarding the mesh size and the number of rings. We used the Harris response, which describes the saliency of the object, for our tests.Para facilitar el procesamiento de objetos 3D, es común utilizar representaciones de alto nivel, como los descriptores locales que generalmente se calculan utilizando vecindarios definidos. K-rings es una técnica para definirlos y es ampliamente utilizada por varios métodos. En este trabajo, proponemos un modelo para el cálculo distribuido de descriptores locales sobre mallas triangulares 3D, utilizando el concepto de anillos k. En nuestros experimentos, medimos el rendimiento de nuestro modelo en mallas enormes, evaluando la aceleración, la escalabilidad y el tiempo de cálculo del descriptor. Mostramos la configuración óptima de nuestro modelo para el clúster que implementamos y el crecimiento lineal del tiempo de cálculo con respecto al tamaño de la malla y el número de anillos. Usamos la respuesta de Harris, que describe la prominencia del objeto, para nuestras pruebas

DISSOLUTION PERFORMANCE OF MELOXICAM FORMULATIONS UNDER HYDRODYNAMICS OF USP PADDLE APPARATUS AND FLOW-THROUGH CELL METHOD

Objective: To study the in vitro dissolution performance of four generic formulations of the poorly soluble drug meloxicam and the reference under hydrodynamic environments generated by flow-through cell method and USP paddle apparatus (pharmacopeial test). Methods: Dissolution method was validated according to ICH guidelines. Dissolution profiles were carried out with an automated flow-through cell apparatus (laminar flow at 16 ml/min with 22.6 mm cells) and USP paddle apparatus at 75 rpm. Phosphate buffer pH 7.5 at 37.0±0.5 °C was used as dissolution medium. Spectrophotometric determination of drug at 362 nm was carried out during 30 min. Dissolution profiles were compared with model-dependent and-independent methods. Results: Practically, all generic formulations showed significant differences with the percentage of drug dissolved at 30 min, mean dissolution time and dissolution efficiency, when USP paddle apparatus was used (*P&lt;0.05), while only two generic formulations were different to reference using flow-through cell method. After adjustment to different mathematical equations, Weibull function was the best model to describe meloxicam dissolution performance and significant differences were found with all drug products when USP paddle apparatus was used, while only one formulation was different with flow-through cell method. Conclusion: The study reveals the need to look for better dissolution schemes for meloxicam tablets since USP paddle apparatus may not reflect properly the in vitro dissolution performance of meloxicam generic formulations and reference

A review on the properties of cellulose fibre insulation

The building sector is constantly innovating in its use of materials with regards to sustainability. There is a need to use cost effective, environmentally friendly materials and technologies which lessen the impact of a construction in terms of its use of non-renewable resources and energy consumption. Cellulose fibre insulation is an eco-friendly thermal insulation material made from recycled paper fibres. It offers good thermal properties and has a low embodied energy. However due to lack of expertise in its application and properties, cellulose insulation is not widely used in comparison to more traditional insulation materials. The present paper reviews the available research on cellulose fibre insulation, its manufacture, installation, and performance. The paper focuses the physical properties of cellulose insulation, the environmental factors that affect these properties, and possible means of future innovation

The properties of cellulose insulation applied via the wet spray process

Cellulose fibre insulation is a sustainable thermal insulation material made out of recycled paper. It can be installed in open walled cavities using the wet spray method. The isotherm of loose cellulose insulation fibres was determined using dynamic vapour sorption to study their relationship with water. The types of water within the fibres, known as bound and unbound water was studied via a differential scanning calorimetry method. Wet spray cellulose samples were produced with varying water content and subjected to compression, and thermal conductivity testing. Results showed that density, modulus of elasticity, and thermal conductivity all increased with water dosage. The increase in these properties was higher when the material was sprayed with water than when it was dry compacted. These are factors which need to be considered for when applying wet-spray cellulose fibre insulation, in order to ensure the properties of the material are consisten

Proyecto de exportación de chompas de alpaca al mercado de los Estados Unidos

La empresa a crear estará dedicada al acopio y comercialización (exportación) de chompas de alpaca, productos que serán enviados a los estados Unidos con preferencia al Estado de Nueva York, el cual está localizado al noreste de dicho país.Tesi

IN VITRO EQUIVALENCE STUDY OF DIFFERENT DOSES OF CARBAMAZEPINE REFERENCE TABLETS USING USP APPARATUSES 2 AND 4

Objective: To perform an in vitro equivalence study of two doses of carbamazepine reference tablets sold in the local market under hydrodynamic conditions of USP Apparatus 4, a dissolution apparatus that better simulates the human gastrointestinal tract. Results were compared with dissolution official conditions using USP Apparatus 2. Methods: Dissolution profiles of both formulations were carried out with an automated USP Apparatus 2 at 75 rpm and 900 ml of dissolution medium. USP Apparatus 4 with laminar flow at 16 ml/min and 22.6 mm cells were used. 1% lauryl sulfate aqueous solution at 37.0±0.5 °C was used as dissolution medium. Spectrophotometric determination of drug at 285 nm was carried out during 60 min. Dissolution profiles were compared with model-independent and-dependent approaches. Results: When comparing dissolution profiles of low vs. high dose similar profiles were found (f2&gt;50) in each dissolution apparatus, however, when the same dose was compared, USP 2 vs. USP 4, opposite results were obtained. Comparison of mean dissolution time and dissolution efficiency data corroborates these results. Weibull function was the best mathematical model that described the in vitro dissolution performance of carbamazepine. No significant differences were found in Td values (low vs. high dose) but opposite results were also found with USP 2 vs. USP 4. Conclusion: Equivalent dissolution performance of two doses of carbamazepine reference tablets were found in each USP dissolution apparatus. The main problem identified in this comparative study is the low dissolution rate and extent found with USP Apparatus 4. More research on this field is necessary for all available doses of reference drug products since the quality of generic formulations depends on the quality of references

INFLUENCE OF DOSE AND USP DISSOLUTION APPARATUS IN THE RELEASE PERFORMANCE OF REFERENCE TABLETS: PROPRANOLOL-HCl AND RANITIDINE-HCl CASES

Objective: Due to quality of generic formulations depends on available information of reference drug products the aim of this work was to perform an in vitro dissolution study of two doses of propranolol-HCl and ranitidine-HCl reference tablets using USP basket or paddle apparatus and flow-through cell method. Methods: Two doses of propranolol-HCl (10-mg and 80-mg) and ranitidine-HCl (150-mg and 300-mg) of Mexican reference products were used. Dissolution profiles of propranolol-HCl were obtained with USP basket apparatus at 100 rpm and 1000 ml of 1% hydrochloric acid. Profiles of ranitidine-HCl were determined with USP paddle apparatus at 50 rpm and 900 ml of distilled water. All formulations were also studied with the flow-through cell method using laminar flow at 16 ml/min. Dissolution profiles were compared by model-independent (f2 similarity factor, mean dissolution time and dissolution efficiency) and model-dependent methods (dissolution data adjusted to some mathematical equations). Time data, derived from these adjustments, as t50%, t63.25%, and t85% were used to compare dissolution profiles. Results: With all approaches used and being high solubility drugs significant differences were found between low and high doses and between USP dissolution apparatuses (*P&lt;0.05). Conclusion: In vitro dissolution performance of two doses of propranolol-HCl and ranitidine-HCl was not expected. Considering the same USP dissolution apparatus, the reference tablets did not allow the simultaneous release of the used doses. The results could be of interest for pharmaceutical laboratories or health authorities that classify some drug products as a reference to be used in dissolution and bioequivalence studies