1,720,978 research outputs found
Effect of antioxidant active films on the oxidation of soybean oil monitored by Fourier transform infrared spectroscopy
No full textAn active film prepared from waterborne polyurethane incorporated with different concentrations of butylated hydroxytoluene (BHT) and a-tocopherol was developed, and the films’ antioxidant character- istics were studied using soybean oil as food model. The release behavior of additives from such films was studied using isooctane as a simulant fatty food. Antioxidant activity of the films into soybean oil at three experimental conditions was monitored by FTIR spectroscopy. Induction time and the kinetics of the oxi- dation process were followed using different bands of the FT-IR spectra. Films incorporated with 2 wt.% of BHT or a-tocopherol showed enough antioxidant activity to preclude oil oxidation during 60 days at 60 °C in the dark. The results showed that this type of active films could be used for food preservation as part of a packaging containing oils or oily related products.Fil: Anbinder, Pablo. UNLP (Universidad Nacional de La Plata). INIFTA (Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas). CONICET; ArgentinaFil: Peruzzo, Pablo. UNLP (Universidad Nacional de La Plata). INIFTA (Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas). CONICET; ArgentinaFil: Martino, Miriam. CIDCA (Centro de Investigación y Desarrollo en Criotecnología de Alimentos). CONICET; ArgentinaFil: Amalvy, Javier. UNLP (Universidad Nacional de La Plata). INIFTA (Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas). CONICET. CIDEPINT (Centro de Investigación y Desarrollo en Tecnología de Pinturas) CONICET/CICPBA. UTN (Universidad Tecnológica Nacional). CITEMA (Centro de Investigación y Desarrollo en Ciencia y Tecnología de Materiales); ArgentinaPeer Reviewe
Effect of food additives on the microstructure, mechanical and water transport properties of polyurethane films
No full textThe objective of this work is to study the effects of common food preservatives (BHT, α-tocopherol, EDTA-Na and potassium sorbate) on the morphological, mechanical and water transport properties of polyurethane (PU) as films or coatings. The influence of these additives on the polymer structure and the polymer-additive interaction was evaluated by using SAXS, FTIR and DSC. The addition of additives results either in the formation of aggregates or modification of the polymer microstructure, depending on the molecular size and nature of additive, i.e. number of polar groups, hydrophilicity, etc. The addition of BHT molecules seems to break the typical hard segments interactions in PUs, leading therefore to a good incorporation of the molecule in the polymer matrix, however, α-tocopherol does not incorporate onto the PU matrix leading to an evident phase separation and not affecting therefore the microrange of heterogeneities of the PU matrix. On the contrary, films doped with EDTA-Na or potassium sorbate showed important changes in both soft and hard segments domains. As consequence, the water transport properties were greatly affected by the incorporation of these food additives in the polymeric matrix. Films with potential antimicrobial or antioxidant activity were obtained, with a moderated decrease in the mechanical properties.Fil: Anbinder, Pablo Sebastián. Universidad Nacional del Centro de la Pcia.de Bs.as.. Centro de Investigaciones En Física E Ingeniería del Centro de la Provincia de Buenos Aires. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones En Física E Ingeniería del Centro de la Provincia de Buenos Aires. Provincia de Buenos Aires. Gobernación. Comision de Invest.científicas. Centro de Investigaciones En Física E Ingeniería del Centro de la Provincia D; ArgentinaFil: Peruzzo, Pablo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Instituto de Investigaciones Fisico-químicas Teóricas y Aplicadas. Universidad Nacional de la Plata. Facultad de Cs.exactas. Instituto de Investigaciones Fisico-químicas Teóricas y Aplicadas; ArgentinaFil: Amalvy, Javier. Universidad Tecnologica Nacional. Facultad Regional La Plata; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Surface, thermal, and mechanical properties of composites and nanocomposites of polyurethane/PTFE nanoparticles
Get PDFFilms from blends of polyurethane and nano-polytetrafluoroethylene aqueous dispersions (PU/nanoPTFE) were prepared, and the effect of the addition of different amounts of PTFE nanoparticles (50 nm) was studied. The changes in the superficial
properties of the films were studied by means of XPS, ATR/FTIR, and contact angle measurements. SEM and TEM results are also included. The contact angle values confirm the surface hydrophobicity of composite films. Even though nanoparticles are present in the bulk, higher concentrations of particles appear at the surface in samples with lower nanoPTFE content (up to 10 wt%), as revealed by XPS. Higher amounts of nanoPTFE particles cause aggregation. The mechanical and thermal properties of composites are also discussed.Fil: Anbinder, Pablo Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Peruzzo, Pablo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: de Siervo, Abner. Universidade Estadual de Campinas; BrasilFil: Amalvy, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigación y Desarrollo en Tecnología de Pinturas (i); Argentin
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Effect of antioxidant active films on the oxidation of soybean oil monitored by Fourier Transform Infrared Spectroscopy
Get PDFAn active film prepared from waterborne polyurethane incorporated with different concentrations of butylated hydroxytoluene (BHT) and α-tocopherol was developed, and the films? antioxidant characteristics were studied using soybean oil as food model. The release behavior of additives from such films was studied using isooctane as a simulant fatty food. Antioxidant activity of the films into soybean oil at three experimental conditions was monitored by FTIR spectroscopy. Induction time and the kinetics of the oxidation process were followed using different bands of the FT-IR spectra. Films incorporated with 2 wt.% of BHT or α-tocopherol showed enough antioxidant activity to preclude oil oxidation during 60 days at 60 °C in the dark. The results showed that this type of active films could be used for food preservation as part of a packaging containing oils or oily related products.Fil: Anbinder, Pablo Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Peruzzo, Pablo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Martino, Miriam Nora. 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; ArgentinaFil: Amalvy, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigación y Desarrollo en Tecnología de Pinturas (i); Argentin
Morphological changes induced by advanced glycation endproducts in osteoblastic cells: Effects of co-incubation with alendronate
No full textAdvanced glycation endproducts (AGEs) accumulate with age in various tissues, and are further increased in patients with Diabetes mellitus, in which they are believed to contribute to the development and progression of chronic complications that include a decrease in bone quality. Bisphosphonates are anti-osteoporotic drugs that have been used for the treatment of patients with diabetic bone alterations, although with contradictory results. In the present study, we have evaluated the in vitro alterations on osteoblastic morphology by environmental scanning electron microscopy, in actin cytoskeleton and apoptosis induced by AGEs, as well as the modulation of these effects by alendronate (an N-containing bisphosphonate). Our present results provide evidence for disruption induced by AGEs of the osteoblastic actin cytoskeleton (geodesic domes) and significant alterations in cell morphology with a decrease in cell-substratum interactions leading to an increase in apoptosis of osteoblasts and a decrease in osteoblastic proliferation. High concentrations of alendronate (10−5 M, such as could be expected in an osteoclastic lacuna) further increase osteoblastic morphological and cytoskeletal alterations. However, low doses of alendronate (10−8 M, compatible with extracellular fluid levels to which an osteoblast could be exposed for most of its life cycle) do not affect cell morphology, and in addition are able to prevent AGEs-induced alterations and consequently apoptosis of osteoblasts.Fil: Gangoiti, Maria Virginia. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biologicas. Laboratorio de Investigacion en Osteospatias y Metabolismo Mineral; ArgentinaFil: Anbinder, Pablo Sebastián. Universidad Nacional de la Plata. Facultad de Ingenieria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Cortizo, Ana Maria. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biologicas. Laboratorio de Investigacion en Osteospatias y Metabolismo Mineral; ArgentinaFil: Mccarthy, Antonio Desmond. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biologicas. Laboratorio de Investigacion en Osteospatias y Metabolismo Mineral; Argentin
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
