Biodegradable materials based on poly(vinyl alcohol) (PVA) and poly (lactic acid) (PLA) with antioxidant and antimicrobial activity for food packaging applications

Tesis por compendio[ES] El uso masivo de plásticos y su impacto medioambiental, así como la necesidad de mejorar la conservación de los alimentos, hace necesario el desarrollo de alternativas biodegradables para el envasado activo de alimentos. La presente Tesis Doctoral, se ha centrado en el desarrollo de películas activas, basados en polímeros biodegradables con propiedades complementarias, con el fin de obtener materiales con propiedades mecánicas y de barrera adecuadas para cumplir con los requisitos del envasado alimentario. Para ello, se consideraron el poli (vinil alcohol) (PVA) y el poli (ácido láctico) PLA. Asimismo, el carvacrol y los ácidos ferúlico y cinámico fueron elegidos como compuestos activos naturales. Se estudió la encapsulación del carvacrol en liposomas de diferentes tipos de lecitina para mejorar su retención durante la etapa de formación del film. La lecitina de soja enriquecida en fosfatidilcolina fue la más eficaz para mantener la estabilidad de la emulsión de carvacrol, resultando en films con mayor retención. La incorporación de carvacrol (encapsulado o no), modificó ligeramente la microestructura y las propiedades físicas de los films, así como la cristalinidad y el comportamiento térmico del polímero. El PVA totalmente hidrolizado proporcionó films con un mejor desempeño mecánico y capacidad de barrera al oxígeno, pero con menor retención de carvacrol. Por el contrario, el PVA parcialmente hidrolizado dio lugar a films más homogéneos, con mayor contenido de carvacrol. Mientras que los grupos acetilos protegieron al polímero de la termodegradación, permitiendo la obtención de films mediante las técnicas habituales del procesado industrial. Por lo tanto, el PVA parcialmente hidrolizado tiene un gran potencial para la producción de films activos, con más posibilidades de procesamiento que el PVA totalmente hidrolizado. Se incorporaron también ácido cinámico y ferúlico, con menor impacto sensorial que el del carvacrol, al PVA parcial y totalmente hidrolizado, mediante casting de las soluciones acuosas con glicerol para mejorar la solubilidad de los ácidos. Los films de PVA plastificados con glicerol mostraron una menor capacidad de barrera que los no plastificados. La incorporación del ácido ferúlico promovió mayores cambios en las propiedades de los films que el ácido cinámico, debido a un efecto de reticulación, que promovió la cristalinidad, la rigidez y la capacidad de barrera del material. También se obtuvieron películas plastificadas a base de PVA parcialmente hidrolizado con ácidos fenólicos, mediante mezclado en fundido y moldeo por compresión. Los films termoprocesados fueron menos extensibles y resistentes a la rotura y más permeables al oxígeno y al vapor de agua. Estudios in vitro demostraron que los films con ácidos fenólicos obtenidos por casting o termoprocesado presentaron actividad antioxidante y antimicrobiana, especialmente con ácido ferúlico. Con el objetivo de cumplir los requisitos de envasado de alimentos, se obtuvieron films tricapa por termocompresión, compuestos por una capa central de PVA, cargada con compuestos activos (carvacrol o ácido ferúlico), y dos capas externas de PLA. La termocompresión fue eficaz para la adhesión interlaminar. Las multicapas mostraron un rendimiento mecánico próximo al de los films de PLA y una elevada capacidad de barrera al oxígeno y al vapor de agua. Todos los laminados con compuestos activos incorporados a la capa de PVA fueron eficaces para controlar el crecimiento microbiano en filetes de carne de vacuno envasada. Por tanto, el laminado de films de PVA y PLA parcialmente hidrolizado representa una estrategia adecuada para obtener materiales de envasado con propiedades funcionales más próximas a las de algunos plásticos convencionales utilizados en el envasado alimentario. Asimismo, estos materiales con carvacrol o ácido ferúlico incorporados podrían utilizarse para el envasado de alimentos altamente susceptibles a procesos oxidativos o de degradación microbiológica para alargar su vida útil.[CA] L'ús massiu de plàstics i el seu impacte mediambiental, així com la necessitat de millorar la conservació dels aliments, fa necessari el desenvolupament d'alternatives biodegradables per a l'envasament actiu d'aliments. La present Tesi Doctoral, s'ha centrat en el desenvolupament de pel·lícules actives, basats en polímers biodegradables amb propietats complementàries, amb la finalitat d'obtindre materials amb propietats mecàniques i de barrera adequades per a complir amb els requisits de l'envasament alimentari. Per a això, es van considerar el poli (vinil alcohol) (PVA) i el poli (àcid làctic) PLA. Així mateix, es van triar el carvacrol i els àcids ferúlic i cinàmic, com a compostos actius. Es va estudiar l'encapsulació del carvacrol en liposomes de diferents tipus de lecitina per a millorar la seua retenció durant l'etapa de formació del film. La lecitina de soja enriquida en fosfatidilcolina va ser la més eficaç per a mantindre l'estabilitat de l'emulsió de carvacrol, resultant en films amb major retenció. La incorporació de carvacrol (encapsulat o no), va modificar lleugerament la microestructura i les propietats físiques dels films, així com la cristalinitat i el comportament tèrmic del polímer. El PVA totalment hidrolitzat va proporcionar films amb un millor exercisc mecànic i capacitat de barrera a l'oxigen, però amb menor retenció de carvacrol. Per contra, el PVA parcialment hidrolitzat va donar lloc a films més homogenis, amb major contingut de carvacrol. Mentre que els grups acetils van protegir el polímer de la termodegradació, permetent l'obtenció de films mitjançant les tècniques habituals del processament industrial. Per tant, el PVA parcialment hidrolitzat té un gran potencial per a la producció de films actius, amb una més àmplia gamma de possibilitats de processament que el PVA totalment hidrolitzat. Es van incorporar també àcid cinàmic i ferúlic, amb menor impacte sensorial que el del carvacrol, al PVA parcial i totalment hidrolitzat, mitjançant càsting de les solucions aquoses amb glicerol per a millorar la solubilitat dels àcids. Els films de PVA plastificats amb glicerol van mostrar una menor capacitat de barrera que els no plastificats. La incorporació de l'àcid ferúlic va promoure majors canvis en les propietats dels films que l'àcid cinàmic, a causa d'un efecte de reticulació, que va promoure la cristalinitad, la rigidesa i la capacitat de barrera del material. També es van obtindre pel·lícules plastificades a base de PVA parcialment hidrolitzat amb àcids fenòlics, mitjançant barrejat en fos i emotlament per compressió. Els films termoprocessats van ser menys extensibles i resistents al trencament i més permeables a l'oxigen i al vapor d'aigua. Estudis in vitro van demostrar que els films amb àcids fenòlics obtinguts per càsting o termoprocessat van presentar activitat antioxidant i antimicrobiana, especialment amb àcid ferúlic. Amb l'objectiu de complir els requisits d'envasament d'aliments, es van obtindre films tricapa per termocompressió, compostos per una capa central de *PVA, carregada amb compostos actius (carvacrol o àcid ferúlic), i dues capes externes de PLA. La termocompressió va ser eficaç per a l'adhesió interlaminar. Les multicapes van mostrar un rendiment mecànic pròxim al dels films de PLA i una elevada capacitat de barrera a l'oxigen i al vapor d'aigua. Tots els laminatges amb compostos actius incorporats a la capa de PVA van ser eficaces per a controlar el creixement microbià en filets de carn de boví envasada. Per tant, el laminatge de films de PVA i PLA parcialment hidrolitzat representa una estratègia adequada per a obtindre materials d'envasament amb propietats funcionals més pròximes a les d'alguns plàstics sintètics utilitzats en l'envasament alimentari. Així mateix, aquests materials amb carvacrol o àcid ferúlic incorporats podrien utilitzar-se per a l'envasament d'aliments altament susceptibles a processos oxidatius o de degradació microbiològica per a allargar la seua vida útil.[EN] The massive use of synthetic plastics and their environmental impact, as well as the need of improving food preservation, makes necessary the development of biodegradable alternatives for food active packaging. The use of active compounds from natural origin to obtain this kind of materials is a new trend based of the consumer demand for safer and healthier products. The present Doctoral Thesis, has been focused on the development of active packaging films, based on biodegradable polymers with complementary properties, in order to obtain materials with adequate mechanical and barrier properties to meet food packaging requirements. To this end, poly (vinyl alcohol) (PVA) and poly (lactic acid) (PLA) were considered. Likewise, carvacrol and ferulic and cinnamic acid, were chosen as active natural compounds. The liposomal encapsulation of carvacrol, using different kinds of lecithin was evaluated in order to improve the carvacrol retention in the polymer matrix during the film formation step. Soy lecithin enriched in phosphatidylcholine was the most effective at maintaining the stability of the carvacrol emulsion, leading to its highest retention in the PVA films. Incorporation of carvacrol (lecithin encapsulated or not) slightly modified the film microstructure and physical properties and polymer crystallinity and thermal behaviour. The fully hydrolysed PVA provided films with a better mechanical performance and oxygen barrier capacity, but with less carvacrol retention. In contrast, partially hydrolysed PVA gave rise to more homogenous films with a higher carvacrol content. Acetyl groups protect the polymer for thermodegradation, allowing the film production using the common industrial thermoplastic processing techniques. Therefore, partially hydrolysed PVA has a great potential for the production of active films, with a wider range of processing possibilities than fully hydrolysed PVA. Cinnamic and ferulic acids, with lower potential sensory impact than of carvacrol, were also incorporated into partially and fully hydrolysed PVA by casting of aqueous solutions containing glycerol to improve the acid solubility. Glycerol plasticized PVA films exhibited poorer barrier capacity than those non-plasticized. The incorporation of ferulic acid promoted greater changes in the film properties than cinnamic acid, due to a crosslinking effect, which promoted crystallinity, stiffness and barrier capacity of the material. Glycerol plasticized films based on partially hydrolysed PVA with phenolic acids were also obtained by melt blending and compression moulding. Termoprocessed films were less stretchable and resistant to break and more permeable to oxygen and water vapor. In vitro studies demonstrated that cast and termoprocessed films containing phenolic acids exhibited antioxidant and antimicrobial activity, especially with ferulic acid. Three-layer films composed of a central layer of PVA loaded with active compounds (carvacrol lecithin encapsulated or not, or ferulic acid) and two external PLA layers were obtained by thermo-compression, aimed to meet food packaging requirements. Thermocompression was effective for the interlaminar adhesion. Multilayers exhibited mechanical performance close to the PLA sheets and high oxygen and water vapour barrier capacity. All laminates with active compounds incorporated into the PVA sheet were effective at controlling microbial growth in packaged beef meet. Therefore, lamination of partially hydrolysed PVA and PLA films represents a successful strategy to obtain packaging materials with functional properties closer to those of some conventional plastics commonly used in food packaging. Likewise, these materials incorporating carvacrol or ferulic acid could be used for packaging of foods highly susceptible to oxidative or microbiological degradative process to extend their shelf life.The authors acknowledge the financial support of the Agencia Estatal de Investigacion, Ministerio de Economía y Competitividad (MINECO) of Spain through the projects AGL2016-76699-R and PID2019-105207RB-100. Author Johana Andrade thanks the Departamento de Nariño-Colombia y la Fundación CEIBA for the doctoral grant. The authors also thank the services rendered by the Electron Microscopy Service of the UPV.Andrade Chapal, JC. (2021). Biodegradable materials based on poly(vinyl alcohol) (PVA) and poly (lactic acid) (PLA) with antioxidant and antimicrobial activity for food packaging applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/175566TESISCompendi

Destruction and detachment of the western ego in the moresby couple in the sheltering sky by Paul Bowles.

This thesis will analyze the psychological changes of the characters as they are devoured by the wilderness and the vastness of the desert, and how the travelers¿ decision to embrace the wilderness ultimately leads them to be freed of their ego, but also condemns them to realize that they are left alone in a new culture that does not want them or accept them. Port¿s abandonment of his Western ego results from his distaste with the current Western society, the stain left by war, and the false ideals and masks of intellectualism. An unpublished writer, Port embraces the idea that in order to write, one must detach oneself from all that is banal. Kit, who embodies the Western culture, tags along with Port on his unusual adventures because she cherishes him and wants to save their marriage, but she quickly finds herself abandoned and surrounded by a strange and violent world. The trip begins with the three arriving in North Africa. Port is a traveler and this place provides the escape from the mechanized era he has longed for. Arriving at the port of Tanger with Kit and their friend, Turner, he soon regrets his decision, but is unwilling to admit this since it was his idea to go to Africa in the first place. As they advance deeper into the wilderness, the characters find themselves consumed by their rejection of the Western ego, while at the same time they suffer from the rejection by this new civilization they are so eager to embrace.The relationship between the characters, Kit ¿s love for Port and their discontentment with the presence of Turner, will be studied from a psychoanalytical perspective, as the novel is filled with the inner monologues of the characters and their impressions of their companions. It will focus on how their interactions lead them to slowly reshape, lose, or abandon their idea of Western ego and how their travels deep into the wilderness affect them. The Moresby couple, Kit and Port, are the main characters of the novel, with Turner being more of embodiment of the Western world Port is trying to flee. Both of them represent a different angle on the loss of the Western ego and the harshness of abandoning the only culture to which they belong. The essay will explore their motivations for rejecting conventional American values. For Port, this involves an avoidance of emotional responsibilities and a fascination for the unknown, as represented by the desert and the sky. Kit, on the other hand, attempts to deny the disintegration and destruction of her Western ego, fearing consumption of her own sense of self. The novel ¿s three chapters are connected to the evolution of the characters as they move further away from the Western culture they despise while at the same time gradually losing their own selves. This thesis will explore the tragic consequences this entails. Its methods will derive from New Criticism and Psychoanalytic Criticism. Both approaches focus on the the construction and development of the core theme, examining the psyche of the characters and their interactions with one another and with the environment.PregradoLICENCIADO(A) EN LENGUAS EXTRANJERAS INGLÉS - FRANCÉ

Effect of storage duration and analyte concentration on measurement of neutral pH clinical chemistry urine analytes

Background: The aim of the study was focused very keenly in measuring the changes in concentration of sodium, potassium and creatinine in urine, stored for 60 days effect of urinary storage duration of clinical chemistry analytes. This study determined whether patient urine samples can be used for day to day urine quality control.Methods: Spot urine samples were collected from left over samples from the admitted patients in various hospital wards. The samples are kept which its pH was unaltered or unspiked and was aliquoted and deep fridged immediately. These aliquots were melted at an incubator temperature of 86 ºC and was analyzed in the analyzer for 60 days and data were collected for checking variations.Results: With the strenous and continious monitoring from the side of the researchers, the researchers had throughly analysed and found that in both the sets almost all of those analysed urine test of pH 5 and analytes remained very much stable for a period of 60 days which could be used for running daily internal quality controls.Conclusions: Patient urine can be used as internal quality control sample for at least 60 days for sodium, potassium and creatinine. During the 60 days period, there is no appreciable degradation of any of the two sets of samples for sodium, potassium and creatinine measurements

Comparison of direct total iron binding capacity by light MgCO3 and heavy MgCO3

Background: The aim of the study is focused to measure TIBC by calculated method (TIBC using the magnesium carbonate- MgCO3 adsorption), measurement of TIBC by calculatory method from automated UIBC and automated Iron measurement. Latter these two values are to be added and would give an additive result of TIBC. The experiment would be performed by using the light MgCO3 powder and the heavy MgCO3 powder and check for any differences in their respective values. Regression analysis, Bland Altman analysis or histogram analysis of TIBC results obtained by calculated methods in patient samples to find correlation between the two methods is being performed.Methods: Samples received for analysis of tests, regardless of patient identification with sample volume serum were used for the study. After complete analysis and reporting of the sample, the leftover serum was used. Serum was kept at room temperature. Then the calculated TIBC from UIBC and the IRON were compared after doing batch calibration for UIBC and lot calibration of Iron.Results: It was found that, this study had positive bias by the usage of the heavy MgCO3 powder. Positive bias in unsaturated iron binding capacity observed by both methods is studied and further investigated using data obtained during the experiment.Conclusions: There is a higher yield of serum obtained with the heavy MgCO3 powder, TIBC calculated from iron and unsaturated iron binding capacity as compared to TIBC measured directly using the light MgCO3 powder

HORALAB, implementación de un software en ambiente web destinado a gestionar horarios de la sección de laboratorios y equipos de la Universidad de Nariño

Un aspecto importante en la gestión académica de las universidades es la generación de horarios. En este sentido se desarrolla un software denominado HORALAB que funciona en entorno web, actúa como un componente de Joomla y tiene una serie de módulos para gestionar y mostrar los Horarios que se elaboran en la Seccíon de laboratorios y equipos de la Universidad de Nariño. El propósito de la implementación de HORALAB es optimizar el proceso de asignación de horarios a través de la creación de Franjas para prácticas académicas vía web, cuenta con complejos patrones de repetición de franjas que se pueden crear y ver en un calendario atractivo, Las franjas pueden ser distribuidas en categorías como Laboratorios y se puede personalizar las vistas de calendario para mostrar todas o algunas de estas categorías. El usuario quien hace uso del software puede navegar de manera intuitiva y sin ningún inconveniente, logrando de manera rápida, fácil y detallada la información que desea

TiO2 coated MWCNT decorated by Fe3O4 nanoparticle as electrode material for Supercapacitor Application

TiO2 coated multi wall carbon nanotube (TiCN) and Fe3O4 based electrode material for the application in electro chemical devices has been produced through a simple approach. Morphological and electro chemical properties of the prepared nanocomposites were determined through field emission scanning electron microscopy (FESEM) and cyclic voltammetry (CV) and impedance analysis, respectively. Sol-gel technique was hired to synthesize TiCN and in-situ chemical co-precipitation technique was used for the formation of magnetite particles (Fe3O4) on the surface of acid-modified multiwall carbon nanotube (MWCNT). Maximum specific capacitance obtained from CV is 221 F/g

Intellectual Disability and Assistive Technology: Opening the GATE Wider

The World Health Organization has launched a program to promote Global Cooperation on Assistive Technology (GATE). The objective of the GATE program is to improve access to high quality, affordable assistive technology for people with varying disabilities, diseases, and age-related conditions. As a first step, GATE has developed the assistive products list, a list of priority assistive products based on addressing the greatest need at population level. A specific group of people who can benefit from user appropriate assistive technology are people with intellectual disabilities. However, the use of assistive products by people with intellectual disabilities is a neglected area of research and practice, and offers considerable opportunities for the advancement of population health and the realization of basic human rights. It is unknown how many people with intellectual disabilities globally have access to appropriate assistive products and which factors influence their access. We call for a much greater focus on people with intellectual disabilities within the GATE program. We present a framework for understanding the complex interaction between intellectual disability, health and wellbeing, and assistive technology

Mathematical Formulation of Inverse Scattering and Korteweg-De Vries Equation

Inverse scattering refers to the determination of the solutions of a set of differential equations based on known asymptotic solutions, that is, the solution of Marchenko equation. Marchenko equation was derived using integral equation. The potential function derived from eigenvalues and scattering data seems to be the inverse method of scattering problem. The reflection coefficient with one pole and zero reflection coefficients has been chosen to solve inverse scattering problem. Again this paper deals with the connection between inverse scattering and the Korteweg-de Vries equation and describes variety of examples with Korteweg-de Vries equation: the single-soliton solution, the two-soliton solution and finally the N-soliton solution. Throughout the work, the primary objective is to study some mathematical techniques applied in analyzing the behavior of soliton in the KdV equations. Keywords: Marchenko equation, KdV equation, Solitons, Scattering, Inverse Scattering, Canal

EDTA contamination: a preanalytical cause for interference in iron and unsaturated iron binding capacity assay

Background: The aim of the study is focussed very keenly at performing RCA (root cause analysis) of those particular sample containing the absurd results of the Serum UIBC (Unsaturated Iron Binding Capacity), which was also tallied vigilantly side by side with Serum Iron observed at Clinical Biochemistry laboratory of The New Civil Hospital Surat, Gujarat.Methods: The Absurd value from the samples requested for Serum Iiron and Serum Serum UIBC (Unsaturated Iron Binding Capacity) from month of August 2018 till the month of August 2019 were taken in to account for analysis. RCA (root cause analysis) of absurd value for Serum Iron and Serum UIBC (Unsaturated Iron Binding Capacity) which were prepared was mainly focused on tallying with Serum Calcium and Serum Potassium result.Results: With the continious and strenous monitoring from the side of the researchers, the researchers had throughly analysed and found that in almost all of those analysed test containing absurd results of Serum Iron and Serum UIBC(Unsaturated Iron Binding Capacity) which were some way or the other, associated with absurd results of Serum Calcium along with absurd result of Serum Potassium too from the same samples.Conclusions: The Absurd results of Serum Calcium and Serum Potassium are caused mainly due to pre-analytical errors more likely due to the sample contamination with EDTA (ethylene diamine tetra acetic acid). The contaminated EDTA (ethylene diamine tetra acetic acid) sample cause interference in Serum Iron measurement by producing turbidity in sample and in Serum UIBC (Unsaturated Iron Binding Capacity) by chelating Iron