CARBOXYLATED-CELLULOSE NANOCRYSTALS PRODUCED FROM LIGNOCELLULOSIC SOURCES AND USED AS BARRIER COATING FOR PET FILMS

The obtainment of Cellulose nanocrystal (CNC) from different cellulosic sources recently gained a great attention due to their physical and mechanical properties. CNC can be extracted from variety of bio-based and renewable sources, such as wood, cotton, bacterial cellulose, tunicate cellulose and softwood cellulose and used as reinforced nanocomposites, functional materials and oxygen-barrier layers. The most important factor affecting the nanocellulose production is the relative proportion of cellulose, hemicellulose, and lignin in the source material. The extraction of CNC from cellulosic materials started with a pre-treatment of biomass involving the complete or partial removal of hemicelluloses, lignin, etc. and isolation of cellulose component. After the separation of matrix materials, controlled hydrolysis of the cellulosic fibers is performed in order to produce colloidal suspensions of cellulose crystals. Using of ammonium persulfate (APS) has recently achieved the obtainment of CNC from different cellulose sources without any pre-treatment. APS, a strong oxidizing agent with high water solubility, is able to produce carboxylated CNC having high crystallinity and active carboxyl groups. The conversion of the carboxylic acid groups to the carboxylate form offers active sites for surface modification and templates for the synthesis of nanoparticles. Incorporation of carboxylated–CNC as a functional layer on different substrates have enhanced the barrier (oxygen permeability), mechanical, optical, and antifog properties of the nanocomposites. The aim of this work was to obtain the CNC from two lignocellulosic sources and to characterize them in terms of morphology, crystallinity, charge density and coating properties in order to use CNC as barrier coating for PET films

Posidonia Oceanica And Green Tea Extract As Active Agents For Shelf Life Extension Of Fresh Cut Peach

Nowadays the reduction of food waste and the availability of food all over the world areas are priority keys for society. In this context, the shelf life extension of fresh products in a sustainable way may represent one of the main goals. The aim of the present research work was to extend the shelf life of fresh cut peach slices by using extracts of Posidonia oceanica (POS) and green tea (GT), and compared to the control. Total polyphenols content was assessed by Folin-Ciocalteu method and the antioxidant capacity by DPPH (2,2-Diphenyl-1-Picrylhydrazyl) assay. Antimicrobial activity of the two extracts was initially carried out in vitro by determining the Minimal Inhibitory Concentration (MIC) against Escherichia coli, Listeria innocua, Pseudomonas putida, Staphylococcus aureus, Saccharomyces cerevisiae, Aspergillus niger and Penicillium chrysogenum. The two extracts in vivo on peach slices by dipping were applied (only water for the control), than, slices were placed into low-density polyethylene (LDPE) bag and stored at 3 ± 1°C for up to 7 days. Microbiological analyses, color (L*,a*,b*), total soluble solid (TSS) and titratable acidity (TA) on peach slices were carried out every 3 days. POS showed the highest polyphenols content (615±45 mg Gallic Acid Equivalent/g – mg GAE/g) while GT 526 ± 28 mg GAE/g. The values of EC50, for POS, was 72.42 ± 22.90 mg/L, while for GT 3.80 ± 0.11 mg/L. Trials in vitro showed MIC values of above 2 g/L for POS and above 1 g/L in GT mainly against Gram positive bacteria. POS was also found to lead a growth delay in the case of fungi, approximately 60 h compared to the control. Results related to the Total Aerobic (TAC) and yeasts and moulds (Y&M) counts highlighted that peach slices dipped with POS maintained in the first 5 days of storage the microbiota at lower or analogous levels than those found at t0 (1.80 ± 0.09 log cfu/g respect 2.30 ± 0.11 log cfu/g and 1.80 ± 0.05 log cfu/g respect 1.70 ± 0.03 log cfu/g of the control, respectively for TAC and Y&M). Regarding pomological analysis, after seven days, lightness of the peach slices decreased 28% in POS, 24% in GT and 35% in control. During shelf life TSS increased 8% in the control, 2% in POS and remained unchanged in GT, after seven days. At the same time, TA decreased 30% in POS, 20% in GT treatment and 63% in the control. During the experiment TSS increased in all treatments, more rapidly in the control; meanwhile the TA decreased slowly in treated samples compared to the control. Concluding, Posidonia oceanica and green tea extracts were found able to delay the colour and pomological parameters decay, maintaining a good fruit quality during shelf life. Data already showed evidence a better performance of the Posidonia extract, limiting the growth of microorganisms responsible for fresh fruit deterioration

Efecto de la temperatura sobre la transferencia de agua durante la deshidratación osmótica de papa (Solanum tuberosum L.)

El principal objetivo de este trabajo fue estudiar la cinética de deshidratación osmótica de papa (Solanum Tuberosum L.). Se comparó el ajuste de los datos experimentales con el modelo cinético fenomenológico y con el modelo de Azuara. Para ello, en cubos de 1 cm de arista se evaluó el efecto de la temperatura (30 ºC, 40 ºC y 50 ºC) sobre los coeficiente de difusión efectiva del agua y sólidos. Se determinó la pérdida de peso de agua y la ganancia de sólidos. Las mayores pérdidas de agua se obtuvieron a la temperatura de 50 ºC. Se calcularon los parámetros cinéticos ajustándose adecuadamente a los modelos matemá- ticos respectivos para la pérdida de agua y la ganancia de sólidos. Asimismo, se determinó la energía de activación mediante la ecuación de Arrhenius siendo superior la energía de activación para la difusión en la ganancia de sólidos.The main purpose for this work is to study the osmotic dehydration kinetics of potatoes (Solanum Tuberosum L.). Thus, a comparison of fitness for the experimental data related to the phenomenological kinetic model and Azuara’s model was made. When applying to 1 cm size potatoes cubes, effect of temperature (30 ºC, 40 ºC and 50ºC) on effective diffusivity coefficients for both water and solids was measured. Water weight loss and solids increase was determined. The highest water loss occurred at 50 º C. The different models kinetics parameters were calculated and a good fitness to mathematical respective relationships was obtained, both for water loss and solids increments. Furthermore, activation energy when applying Arrhenius equation was calculated, being higher for the diffusivity of solids gain.Fil: Silva Paz, Reynaldo Justino. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires; Argentina. Universidad Nacional de Entre Rios; ArgentinaFil: Della Rocca, Patricia A.. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires; ArgentinaFil: Tisocco, Osvaldo D.. Universidad Nacional de Entre Ríos. Facultad de Ciencias de la Alimentación; ArgentinaFil: Mascheroni, Rodolfo Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones en Criotecnología de Alimentos (i); Argentina. Universidad Nacional de La Plata; Argentin

Tuning Polyamidoamine Design to Increase Uptake and Efficacy of Ruthenium Complexes for Photodynamic Therapy

Nanomedicine holds great promises to change the way drugs are delivered to their target, owing to the use of nano-sized drug carriers capable to enter cells and be trafficked intracellularly via energy dependent pathways [1, 2]. This is very different from the way most drugs arrive to their target, often based simply on their solubility and partition coefficients in lipids and water. Despite some valuable successes, drug delivery remains rather challenging and several factors are still limiting its potential. Among such factors, it has emerged, for instance, that most nano-sized carriers entering cells via endocytosis are later trafficked along the endolysosomal pathway to the lysosomes, where the low pH and abundant proteases can degrade and destroy the internalised cargo. Strategies to escape the endosomes and lysosomes are being investigated. Among the many polymer species employed as drug delivery vectors, linear polyamidoamines (PAAs) are very interesting and promising materials. In this communication it will be presented a new polycationic PAA endowed with a luminescent Ru complex (Ru-PhenAN) and its ability to target the cell nucleus. It shows unique trafficking to the cell nucleus of all the treated cells, also at polymer doses as low as cytotoxicity is very low. Also, it will be shown the efficacy of Ru-PhenAN as photosensitizers for photodynamic therapy (PDT), a treatment of pathological conditions based on the photo-activation of a bioactive compound, which is not harmful in the absence of light irradiation [3]

Children’s digital skills acquisition in non-formal educational contexts: Pedagogical practices, learning, and inclusion opportunities in coding and robotics workshops.

Coding and robotics education has drawn a lot of interest in recent years to get children ready for the future labour market and advance their digital skills. This paper focuses on coding and robotics workshops in non-formal educational settings in Belgium, Denmark, and Italy. Building on data from a comparative/cross-national study, we will present findings from 16 observations of such workshops followed by 11 interviews with the organisers and moderators with the purpose of investigating their pedagogical practices, learning and inclusion opportunities. Findings of this study suggest that while digital skills workshops in non-formal learning contexts are designed and implemented with the goal of encouraging children's collaboration and active participation, the structure of the learning activities, the organization of the learning environment, and the choices made by children themselves may promote individualistic practices. Furthermore, despite attempts to encourage diversity and inclusion, such as choosing a "free" and "open-door" approach, these workshops may fail to attract participants from diverse backgrounds. We argue that an active dialogue between organisers and moderators, researchers, parents, and, of course, children from various backgrounds is required to promote child-centered approaches that move beyond individualistic accounts of learning and toward the creation of more collaborative and inclusive digital skill activities through a systemic and holistic approach

Evaluation of the antioxidant/antimicrobial performance of Posidonia oceanica in comparison with three commercial natural extracts and as a treatment on fresh-cut peaches (Prunus persica Batsch)

This research aimed at extending the choice of natural antimicrobials/antioxidants for food applications. Four plant extracts, Posidonia oceanica (PO), Green Tea (GT), Grape seeds (GS) and Grape skin (GK), were analyzed to determine their total phenolic content, antioxidant activity and in vitro antimicrobial performance. PO extract showed the highest total phenolic content (711 mg gallic acid/g extract) and antifungal activity against Aspergillus niger and Penicillium chrysogenum. The highest antioxidant (3.81 mg/L EC50) and antibacterial activities (bactericidal against Gram positives and bacteriostatic against Gram negatives) were found for GT extract. The best performing extracts (PO and GT) were applied by dipping on peach slices in storage trials. Microbiological and pomological parameters were evaluated during 7 d storage. Total aerobic count, Pseudomonas as well as yeasts and moulds populations, were reduced by about 0.5 log cfu/g, mainly up to 5 d in all treated samples compared to the control. Total soluble solids, titratable acidity and colour (L*a*b*) changes were also delayed in treated fruit

ESTUDIO DE DOS METODOS DE COCCION EN LA ESTIMACION DE LA TERNEZA DE LA CARNE BOVINA

El estudio fue realizado con el objetivo de determinar el efecto del método de cocción sobre la perdida de agua y la terneza de la carne bovina. Para el estudio fueron seleccionados 20 novillos híbridos de la misma categoría (terminados) y con una edad similar (24 meses), provenientes del Chaco paraguayo. Una vez faenados, las medias reses fueron enfriadas a 4ºC durante 24 horas. De cada media res izquierda se extrajeron dos bifes del músculo Longissimus dorsi a la altura de la 12ª costilla, cada filete midió aproximadamente 2,5cm de ancho y cada uno de ellos se destinaron a los dos tratamientos propuestos. El tratamiento 1, consistió en la cocción por método de baño María; en el tratamiento 2, la cocción del filete fue en grill eléctrico. En ambos tratamientos se registraron los pesos antes y después de la cocción a fin de evaluar las mermas por evaporación del agua debidas a la cocción, la terneza se estimo mediante la técnica de resistencia al corte utilizando un equipo Warner Bratzler. Los datos obtenidos fueron sometidos a técnicas estadísticas "ANAVA" y "Prueba de T" para la comparación de medias, adoptándose un nivel de significancia del 5%. También se utilizo la "Correlación de Pearson" para medir la relación lineal entre las variables cuantitativas (SAS®, versión 8.0). No se encontraron diferencias estadísticas significativas en los valores de perdida de agua medidos a través de las mermas por cocción ni en los valores de terneza medidos por la fuerza de corte del WB. Los valores de fuerza de corte y pérdida de agua presentaron una correlación positiva y estadísticamente significativa

\u201cI Can Share Politics But I Don\u2019t Discuss It\u201d: Everyday Practices of Political Talk on Facebook

The article explores how a group of young people in Germany, Italy, and the United Kingdom experience and manage informal political talk on Facebook. Based on 60 interviews with 14- to 25-year-olds with diverse interest and participation in politics, it understands political talk as a social achievement dependent on the situational definition, shaped by the perceived imagined audiences, shared expectations, and technological affordances. Results show that young people construct different interactional contexts on Facebook depending on their political experiences, but also on their understanding of the affordances of networked publics as shaped by the social norms of their peer groups. Many youth define Facebook as an unsafe social setting for informal political discussions, thus adhering to a form of \u201cpublicness\u201d aimed at neutralizing conflicts. Others, instead, develop different forms of \u201cpublicness\u201d based on emergent communicative skills that help them manage the uncertainty of social media as interactional contexts

A parametric study of a multiphase porous media model for tumor spheroids and environment interactions

Computational models for tumor growth provide an effective in silico tool to investigate the different stages of cancer growth. Recently, a series of computational models based on porous media theory has been proposed to predict tumor evolution and its interactions with the host tissue. In addition, a specialization of the original models, adapted for tumor spheroids, has been proposed and validated experimentally. However, due to the complexity of the modeling framework, a systematic understanding of the role of the parameters governing the equations is still lacking. In this work, we perform a parametric analysis on a set of fundamental parameters appearing in the model equations. We investigate the effects of a variation of these coefficients on the spheroid growth curves and, in particular, on the final radii reached by the cell aggregates in the growth saturation stage. Finally, we provide a discussion of the results and give a brief summary of our findings

A fluorescent reporter system enables spatiotemporal analysis of host cell modification during herpes simplex virus-1 replication.

Herpesviruses are large and complex viruses that have a long history of coevolution with their host species. One important factor in the virus-host interaction is the alteration of intracellular morphology during viral replication with critical implications for viral assembly. However, the details of this remodeling event are not well understood, in part because insufficient tools are available to deconstruct this highly heterogeneous process. To provide an accurate and reliable method of investigating the spatiotemporal dynamics of virus-induced changes to cellular architecture, we constructed a dual-fluorescent reporter virus that enabled us to classify four distinct stages in the infection cycle of herpes simplex virus-1 at the single cell level. This timestamping method can accurately track the infection cycle across a wide range of multiplicities of infection. We used high-resolution fluorescence microscopy analysis of cellular structures in live and fixed cells in concert with our reporter virus to generate a detailed and chronological overview of the spatial and temporal reorganization during viral replication. The highly orchestrated and striking relocation of many organelles around the compartments of secondary envelopment during transition from early to late gene expression suggests that the reshaping of these compartments is essential for virus assembly. We furthermore find that accumulation of HSV-1 capsids in the cytoplasm is accompanied by fragmentation of the Golgi apparatus with potential impact on the late steps of viral assembly. We anticipate that in the future similar tools can be systematically applied for the systems-level analysis of intracellular morphology during replication of other viruses