108 research outputs found

    Network of topological nodal planes, multifold degeneracies, and Weyl points in CoSi

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    We report the identification of symmetry-enforced nodal planes (NPs) in CoSi providing the missing topological charges in an entire network of band-crossings comprising in addition multifold degeneracies and Weyl points, such that the fermion doubling theorem is satisfied. In our study we have combined measurements of Shubnikov-de Haas (SdH) oscillations in CoSi with material-specific calculations of the electronic structure and Berry curvature, as well as a general analysis of the band topology of space group (SG) 198. The observation of two nearly dispersionless SdH frequency branches provides unambiguous evidence of four Fermi surface sheets at the R point that reflect the symmetry-enforced orthogonality of the underlying wave functions at the intersections with the NPs. Hence, irrespective of the spin-orbit coupling strength, SG198 features always six- and fourfold degenerate crossings at R and Γ\Gamma that are intimately connected to the topological charges distributed across the network

    Elastomeric polyamide biomaterials with stereochemically tuneable mechanical properties and shape memory

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    Abstract: Biocompatible polymers are widely used in tissue engineering and biomedical device applications. However, few biomaterials are suitable for use as long-term implants and these examples usually possess limited property scope, can be difficult to process, and are non-responsive to external stimuli. Here, we report a class of easily processable polyamides with stereocontrolled mechanical properties and high-fidelity shape memory behaviour. We synthesise these materials using the efficient nucleophilic thiol-yne reaction between a dipropiolamide and dithiol to yield an α,β − unsaturated carbonyl moiety along the polymer backbone. By rationally exploiting reaction conditions, the alkene stereochemistry is modulated between 35–82% cis content and the stereochemistry dictates the bulk material properties such as tensile strength, modulus, and glass transition. Further access to materials possessing a broader range of thermal and mechanical properties is accomplished by polymerising a variety of commercially available dithiols with the dipropiolamide monomer

    Scapinin, the Protein Phosphatase 1 Binding Protein, Enhances Cell Spreading and Motility by Interacting with the Actin Cytoskeleton

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    Copyright (c) 2009 Sagara et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Scapinin, also named phactr3, is an actin and protein phosphatase 1 (PP1) binding protein, which is expressed in the adult brain and some tumor cells. At present, the role(s) of scapinin in the brain and tumors are poorly understood. We show that the RPEL-repeat domain of scapinin, which is responsible for its direct interaction with actin, inhibits actin polymerization in vitro. Next, we established a Hela cell line, where scapinin expression was induced by tetracycline. In these cells, expression of scapinin stimulated cell spreading and motility. Scapinin was colocalized with actin at the edge of spreading cells. To explore the roles of the RPEL-repeat and PP1-binding domains, we expressed wild-type and mutant scapinins as fusion proteins with green fluorescence protein (GFP) in Cos7 cells. Expression of GFP-scapinin (wild type) also stimulated cell spreading, but mutation in the RPEL-repeat domain abolished both the actin binding and the cell spreading activity. PP1-binding deficient mutants strongly induced cell retraction. Long and branched cytoplasmic processes were developed during the cell retraction. These results suggest that scapinin enhances cell spreading and motility through direct interaction with actin and that PP1 plays a regulatory role in scapinin-induced morphological changes.ArticlePLOS ONE. 4(1):e4247 (2009)journal articl

    Clinical characteristics and prognosis of osteosarcoma in young children: a retrospective series of 15 cases

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    <p>Abstract</p> <p>Background</p> <p>Osteosarcoma is the most common primary bone malignancy in childhood and adolescence. However, it is very rare in children under 5 years of age. Although studies in young children are limited in number, they all underline the high rate of amputation in this population, with conflicting results being recently reported regarding their prognosis.</p> <p>Methods</p> <p>To enhance knowledge on the clinical characteristics and prognosis of osteosarcoma in young children, we reviewed the medical records and histology of all children diagnosed with osteosarcoma before the age of five years and treated in SFCE (Société Française des Cancers et leucémies de l'Enfant) centers between 1980 and 2007.</p> <p>Results</p> <p>Fifteen patients from 7 centers were studied. Long bones were involved in 14 cases. Metastases were present at diagnosis in 40% of cases. The histologic type was osteoblastic in 74% of cases. Two patients had a relevant history. One child developed a second malignancy 13 years after osteosarcoma diagnosis.</p> <p>Thirteen children received preoperative chemotherapy including high-dose methotrexate, but only 36% had a good histologic response. Chemotherapy was well tolerated, apart from a case of severe late convulsive encephalopathy in a one-year-old infant. Limb salvage surgery was performed in six cases, with frequent mechanical and infectious complications and variable functional outcomes.</p> <p>Complete remission was obtained in 12 children, six of whom relapsed. With a median follow-up of 5 years, six patients were alive in remission, seven died of their disease (45%), in a broad range of 2 months to 8 years after diagnosis, two were lost to follow-up.</p> <p>Conclusions</p> <p>Osteosarcoma seems to be more aggressive in children under five years of age, and surgical management remains a challange.</p

    Effects of Microwave Heating on Sensory Characteristics of Kiwifruit Puree

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    The effect of microwave processing on the characteristics of kiwifruit puree was evaluated by applying various gentle treatments. Different combinations of microwave power/processing time were applied, with power among 200-1,000 W and time among 60-340 s, and various sensory and instrumental measurements were performed with the aim of establishing correlations and determining which instrumental parameters were the most appropriate to control the quality of kiwi puree. The water and soluble solids of the product, 83 and 14/100 g sample, respectively, did not change due to treatments. For sensory assessment, an expert panel was previously trained to describe the product. Fourteen descriptors were defined, but only the descriptors 'typical kiwifruit colour', 'tone', 'lightness', 'visual consistency' and 'typical taste' were significant to distinguish between kiwifruit puree samples. The instrumental analysis of samples consisted in measuring consistency, viscosity, colour and physicochemical characteristics of the treated and fresh puree. Applying intense treatments (600 W-340 s, 900 W-300 s and 1,000 W-200 s) through high power or long treatment periods or a combination of these factors, mainly affects the consistency (flow distance decreased from 5. 9 to 3. 4 mm/g sample), viscosity (increased from 1. 6 to 2. 5 Pa/s), colour (maximun ¿E was 6 U) and taste of the product. As a result, samples were thicker and with an atypical flavour and kiwifruit colour due to increased clarity (L* increased from 38 to 43) and slight changes in the yellow-green hue (h* decreased from 95 to 94). For the instrumental determinations of colour and visual perception of consistency, the most suitable parameters for quality control are the colour coordinates L*, a*, h*, whiteness index and flow distance measured with a Bostwick consistometer. © 2011 Springer Science+Business Media, LLC.The authors thank the Ministerio de Educacion y Ciencia for the financial support given throughout the Project AGL 2010-22176. The authors are indebted to the Generalitat Valenciana (Valencia, Spain) for the Grant awarded to the author Maria Benlloch. The translation of this paper was funded by the Universidad Politecnica de Valencia, Spain.Benlloch Tinoco, M.; Varela Tomasco, PA.; Salvador Alcaraz, A.; Martínez Navarrete, N. (2012). Effects of Microwave Heating on Sensory Characteristics of Kiwifruit Puree. Food and Bioprocess Technology. 5(8):3021-3031. https://doi.org/10.1007/s11947-011-0652-1S3021303158Albert, A., Varela, P., Salvador, A., & Fiszman, S. M. (2009). Improvement of crunchiness of battered fish nuggets. European Food Research and Technology, 228, 923–930.Alegria, P., Pinheiro, J., Gonçalves, E. M., Fernandes, I., Moldao, M., & Abreu, M. (2010). Evaluation of a pre-cut heat treatment as an alternative to chlorine in minimally processed shredded carrot. Innovative Food Science and Emerging Technologies, 11, 155–161.AOAC. (2000). Official Methods of Analysis of AOAC International. Gaithersburg: AOAC.Barboni, T., Cannac, M., & Chiaramonti, N. (2010). Effect of cold storage and ozone treatment on physicochemical parameters, soluble sugars and organic acids in Actinidia deliciosa. Food Chemistry, 121, 946–951.Beirão-da-Costa, S., Steiner, A., Correia, L., Empis, J., & Moldão-Martins, M. (2006). Effects of maturity stage and mild heat treatments on quality of minimally processed kiwifruitfruit. Journal of Food Engineering, 76, 616–625.Bodart, M., de Peñaranda, R., Deneyer, A., & Flamant, G. (2008). Photometry and colorimetry characterisation of materials in daylighting evaluation tools. Building and Environment, 43, 2046–2058.Bourne, M. C. (1982). Food texture and viscosity-concept and measurement. New York: Academic.Cano, M. P., Hernández, A., & de Ancos, B. (1997). High pressure and temperature effects on enzyme inactivation in strawberry and orange products. Journal of Food Science, 62(1), 85–88.Chiralt, A., Martínez-Navarrete, N., Camacho, M. M., & González, C. (1998). Experimentos de fisicoquímica de alimentos. Valencia: Editorial Universidad Politécnica de Valencia (Chapter 3).Chiralt, A., Martínez-Navarrete, N., González, C., Talens, P., & Moraga, G. (2007). Propiedades físicas de los alimentos. Valencia: Editorial Universidad Politécnica de Valencia (Chapter 16).Contreras, C., Martín, M. E., Martínez-Navarrete, N., & Chiralt, A. (2005). Effect of vacuum impregnation and microwave application on structural changes occurred during air drying of apple. Food Science and Technology/LWT, 38(5), 471–477.Contreras, C., Martín-Esparza, M. E., Martínez-Navarrete, N., & Chiralt, A. (2007). Influence of osmotic pre-treatment and microwave application on properties of air dried strawberry related to structural changes. European Food Research and Technology, 224, 499–504.de Ancos, B., Cano, M. P., Hernández, A., & Monreal, M. (1999). Effects of microwave heating on pigment composition and color of fruit purees. Journal of the Science of Food and Agriculture, 79, 663–670.Dubost, N. J., Shewfelt, R. L., & Eitenmiller, R. R. (2003). Consumer acceptability, sensory and instrumental analysis of peanut soy spreads. Journal of Food Quality, 26, 27–42.Escribano, S., Sánchez, F. J., & Lázaro, A. (2010). Establishment of a sensory characterization protocol for melon (Cucumis melo L.) and its correlation with physical-chemical attributes: indications for future genetics improvements. European Food Research and Technology, 231, 611–621.Fang, L., Jiang, B., & Zhang, T. (2008). Effect of combined high pressure and thermal treatment in kiwifruit peroxidase. Food Chemistry, 109, 802–807.Fisk, C. L., McDaniel, M. R., Strick, B. C., & Zhao, Y. (2006). Physicochemical, sensory, and nutritive qualities of hardy kiwifruit (Actinidia arguta ‘Ananasnaya’) as affected by harvest maturity and storage. Sensory and Nutritive Qualities of Food, 71(3), 204–210.Fúster, C., Préstamo, G., & Cano, M. P. (1994). Drip loss, peroxidase and sensory changes in kiwi fruit slices during frozen storage. Journal of the Science of Food and Agriculture, 64, 23–29.Guldas, M. (2003). Peeling and the physical and chemical properties of kiwi fruit. Journal of Food Processing Preservation, 27, 271–284.Igual, M., Contreras, C., & Martínez-Navarrete, N. (2010). Non-conventional techniques to obtain grapefruit jam. Innovative Food Science and Emerging Technologies, 11, 335–341.Igual, M., García-Martínez, E., Camacho, M. M., & Martínez-Navarrete, N. (2010). Effect of thermal treatment and storage on the stability of organic acids and the functional value of grapefruit juice. Food Chemistry, 118, 291–299.Jaeger, S. R., Rossiter, K. L., Wismer, W. V., & Harker, F. R. (2003). Consumer-driven product development in the kiwifruit industry. Food Quality and Preference, 14, 187–198.Lawless, H., & Heymann, H. (1998). Sensory evaluation of food: Principles and practices. New York: Chapman & Hall.MAPA (2010). Plataforma de conocimiento para el medio rural y pesquero. National Agricultural Statistics Database, Spain, Available at: www.mapa.es . Accessed 05 October 2010.Maskan, M. (2001). Kinetics of colour change of kiwifruits during hot air and microwave drying. Journal of Food Engineering, 48, 169–175.Mohammadi, A., Rafiee, S., Emam-Djomeh, Z., & Keyhani, A. (2008). Kinetic models for colour change in kiwifruit slices during Hoy Air drying. World Journal of Agricultural Sciences, 4(3), 376–383.Moretti, C. L., Mattos, L. M., Machado, C. M. M., & Kluge, R. A. (2007). Physiological and quality attributes associated with different centrifugation times of baby carrots. Horticultura Brasileira, 25, 557–561.Nielsen, S. S. (2010). Food analysis laboratory manual. New York: Springer.Oraguzie, N., Alspach, P., Volz, R., Whitworz, C., Ranatunga, C., Weskett, R., et al. (2009). Postharvest assessment of fruit quality parameters in apple using both instrument and an expert panel. Posthaverst Biology and Technology., 52, 279–287.Pagliarini, E., Laureati, M., & Lavelli, V. (2010). Sensory evaluation of gluten-free breads assessed by a trained panel of celiac assessors. European Food Research and Technology, 231, 37–46.Park, E. Y., & Luh, B. S. (1985). Polyphenol oxidase of kiwifruit. Journal of Food Science, 50, 678–684.Schubert, H., & Regier, M. (2010). The microwave processing of foods. London: Woodhead.Segnini, S., Dejmek, P., & Öste, R. (1999). Relationship between instrumental and sensory analysis of texture and colour of potato chips. Journal of Texture Studies, 30, 677–690.Sinija, V. R., & Mishra, H. N. (2011). Fuzzy analysis of sensory data for quality evaluation and ranking of instant green Tea powder and granules. Food Bioprocess Technology, 4, 408–416.Soufleros, E. H., Pissa, I., Petridis, D., Lygerakis, M., Mermelas, K., Boukouvalas, G., et al. (2001). Instrumental analysis of volatile and other compounds of Greek kiwi wine; sensory evaluation and optimization of its composition. Analytical, Nutritional and Clinical Methods Section, 75, 487–500.Vadivambal, R., & Jayas, D. S. (2007). Changes in quality of microwave-treated agricultural products-a review. Biosystems Engineering, 98, 1–16.Worch, T., Lê, S., & Punter, P. (2010). How reliable are the consumers? Comparison of sensory profiles from consumers and experts. Food Quality and Preference, 21, 309–318.Zanoni, B., Lavelli, V., Ambrosoli, R., Garavaglia, L., Minati, J., & Pagliarini, E. (2007). A model to predict shelf-life in air and darkness of cut, ready-to-use, fresh carrots under both isothermal and non-isothermal conditions. Journal of Food Engineering, 79, 586–591.Zolfaghari, M., Sahari, M. A., Barzegar, M., & Samadloiy, H. (2010). Physicochemical and enzymatic properties of five kiwifruit cultivars during cold storage. Food Bioprocess Technology, 3, 239–246

    Concomitant Control of Mechanical Properties and Degradation in Resorbable Elastomer-like Materials Using Stereochemistry and Stoichiometry for Soft Tissue Engineering

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    YesComplex biological tissues are highly viscoelastic and dynamic. Efforts to repair or replace cartilage, tendon, muscle, and vasculature using materials that facilitate repair and regeneration have been ongoing for decades. However, materials that possess the mechanical, chemical and resorption characteristics necessary to recapitulate these tissues have been difficult to mimic using synthetic resorbable biomaterials. Herein, we report a series of resorbable elastomer-like materials that are compositionally identical and possess varying ratios of cis:trans double bonds in the backbone. These features afford concomitant control over the mechanical and surface eroding degradation properties of these materials. We show the materials can be functionalized post-polymerization with bioactive species and enhance cell adhesion. Furthermore, an in vivo rat model demonstrates that degradation and resorption are dependent on succinate stoichiometry in the elastomers and the results show limited inflammation highlighting their potential for use in soft tissue regeneration and drug delivery
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