Comparative study of the presence of latex and polychloroprene in the behavior of sintered powder EPDMCR, ethylene-propylenediene-monomer crumb rubber

In this work, the mechanical behavior of sintered waste material of ethylene-propylene-diene-monomer crumb rubber (EPDMCR) is analyzed, optimizing the temperature and compression pressure. The results obtained showed that an increase in temperature and compression pressure gives a significant improvement in the mechanical properties of the material. We later mixed the EPDMCR particles with different percentages of adhesives with the aim of further improving the mechanical performance obtained from the sintered particles. The adhesives used in this study were latex and polychloroprene, and the optimum mechanical performance obtained came from mixes with polychloroprene, using a mix with 50% adhesive. The study was concluded with an analysis of images of the material using a scanning electron microscope (SEM), in order to observe the EPDMCR-adhesive interaction.Crespo Amorós, JE.; Parres, F.; Nadal Gisbert, AV. (2012). Comparative study of the presence of latex and polychloroprene in the behavior of sintered powder EPDMCR, ethylene-propylenediene-monomer crumb rubber. Journal of Elastomers and Plastics. 44(2):127-144. doi:10.1177/0095244311418318S127144442Osman, H., Ismail, H., & Mariatti, M. (2007). The Effect of Recycled Newspaper Content and Size on the Properties of Polypropylene (PP)/Natural Rubber (NR) Composites. Polymer-Plastics Technology and Engineering, 47(1), 23-29. doi:10.1080/03602550701575961Crespo, J. E., Parres, F., & Nadal, A. (2009). Mechanical behavior analysis of sintered products of natural rubber crumb rubber (NRCR) using adhesives. Materialwissenschaft und Werkstofftechnik, 40(3), 211-217. doi:10.1002/mawe.200900429Setua, D. K., & Gupta, Y. N. (2007). On the use of micro thermal analysis to characterize compatibility of nitrile rubber blends. 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Recycling of ethylene propylene diene monomer (EPDM) waste. III. Processability of EPDM rubber compound containing ground EPDM vulcanizates. Journal of Applied Polymer Science, 87(14), 2204-2215. doi:10.1002/app.11474Jacob, C., Bhowmick, A. K., De, P. P., & De, S. K. (2002). Studies on ground EPDM vulcanisate as filler in window seal formulation. Plastics, Rubber and Composites, 31(5), 212-219. doi:10.1179/146580102225003029Jacob, C., De, P. P., Bhowmick, A. K., & De, S. K. (2001). Recycling of EPDM waste. II. Replacement of virgin rubber by ground EPDM vulcanizate in EPDM/PP thermoplastic elastomeric composition. Journal of Applied Polymer Science, 82(13), 3304-3312. doi:10.1002/app.2189Jacob, C., De, P. P., Bhowmick, A. K., & De, S. K. (2001). Recycling of EPDM waste. I. Effect of ground EPDM vulcanizate on properties of EPDM rubber. Journal of Applied Polymer Science, 82(13), 3293-3303. doi:10.1002/app.2188Grigoryeva, O. P., Fainleib, A. M., Tolstov, A. L., Starostenko, O. M., Lievana, E., & Karger-Kocsis, J. (2004). Thermoplastic elastomers based on recycled high-density polyethylene, ethylene-propylene-diene monomer rubber, and ground tire rubber. Journal of Applied Polymer Science, 95(3), 659-671. doi:10.1002/app.21177Mathew, G. (2003). Journal of Materials Science, 38(11), 2469-2481. doi:10.1023/a:1023965420749Morin, J. E., Williams, D. E., & Farris, R. J. (2002). A Novel Method to Recycle Scrap Tires: High-Pressure High-Temperature Sintering. Rubber Chemistry and Technology, 75(5), 955-968. doi:10.5254/1.3547695Rajeev, R. S., & De, S. K. (2004). Thermoplastic Elastomers Based on Waste Rubber and Plastics. Rubber Chemistry and Technology, 77(3), 569-578. doi:10.5254/1.3547837Yehia, A. A., Mull, M. A., Ismail, M. N., Hefny, Y. A., & Abdel-Bary, E. M. (2004). Effect of chemically modified waste rubber powder as a filler in natural rubber vulcanizates. Journal of Applied Polymer Science, 93(1), 30-36. doi:10.1002/app.20349Zhang, K., Shen, H., Zhang, X., Lan, R., & Chen, H. (2009). Preparation and Properties of a Waterborne Contact Adhesive Based on Polychloroprene Latex and Styrene-Acrylate Emulsion Blend. Journal of Adhesion Science and Technology, 23(1), 163-175. doi:10.1163/156856108x344658Park, S. W., Kim, B. C., & Lee, D. G. (2009). Tensile Strength of Joints Bonded With a Nano-particle-Reinforced Adhesive. Journal of Adhesion Science and Technology, 23(1), 95-113. doi:10.1163/156856108x344063Buchman, A., Dodiuk-Kenig, H., Dotan, A., Tenne, R., & Kenig, S. (2009). Toughening of Epoxy Adhesives by Nanoparticles. Journal of Adhesion Science and Technology, 23(5), 753-768. doi:10.1163/156856108x379209Likozar, B., & Krajnc, M. (2008). A study of heat transfer during molding of elastomers. Chemical Engineering Science, 63(12), 3181-3192. doi:10.1016/j.ces.2008.03.031Yan, L., Kou, K., Ji, T., Liang, G., & Ha, E. (2007). Application of a new modified epoxy adhesive for bonding fluorine rubber to metal. Journal of Adhesion Science and Technology, 21(15), 1483-1496. doi:10.1163/156856107782844792Smitthipong, W., Nardin, M., Schultz, J., & Suchiva, K. (2007). Adhesion and self-adhesion of rubbers, crosslinked by electron beam irradiation. International Journal of Adhesion and Adhesives, 27(5), 352-357. doi:10.1016/j.ijadhadh.2006.09.010Colom, X., Carrillo, F., & Cañavate, J. (2007). Composites reinforced with reused tyres: Surface oxidant treatment to improve the interfacial compatibility. Composites Part A: Applied Science and Manufacturing, 38(1), 44-50. doi:10.1016/j.compositesa.2006.01.022Liu, L., Luo, Y., Jia, D., Fu, W., & Guo, B. (2006). Structure and Properties of Natural Rubber-Organoclay Nanocomposites Prepared by Grafting and Intercalating Method in Latex. Journal of Elastomers & Plastics, 38(2), 147-161. doi:10.1177/0095244306057425Budrugeac, P. (2001). Thermal degradation of glass reinforced epoxy resin and polychloroprene rubber: the correlation of kinetic parameters of isothermal accelerated aging with those obtained from non-isothermal data. Polymer Degradation and Stability, 74(1), 125-132. doi:10.1016/s0141-3910(01)00112-4Arayasantiparb, D., McKnight, S., & Libera, M. (2001). Compositional variation within the epoxy/adherend interphase. Journal of Adhesion Science and Technology, 15(12), 1463-1484. doi:10.1163/156856101753213312Kim, J. I., Ryu, S. H., & Chang, Y. W. (2000). Mechanical and dynamic mechanical properties of waste rubber powder/HDPE composite. Journal of Applied Polymer Science, 77(12), 2595-2602. doi:10.1002/1097-4628(20000919)77:123.0.co;2-cCepeda-Jiménez, C. M., Pastor-blas, M. M., Ferrándiz-Gómez, T. P., & Martín-Martínez, J. M. (2000). Surface Characterization of Vulcanized Rubber Treated with Sulfuric Acid and its Adhesion to Polyurethane Adhesive. 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Atmospheric emissions from the deepwater Horizon spill constrain air-water partitioning, hydrocarbon fate, and leak rate

The fate of deepwater releases of gas and oil mixtures is initially determined by solubility and volatility of individual hydrocarbon species; these attributes determine partitioning between air and water. Quantifying this partitioning is necessary to constrain simulations of gas and oil transport, to predict marine bioavailability of different fractions of the gas-oil mixture, and to develop a comprehensive picture of the fate of leaked hydrocarbons in the marine environment. Analysis of airborne atmospheric data shows massive amounts (∼258,000 kg/day) of hydrocarbons evaporating promptly from the Deepwater Horizon spill; these data collected during two research flights constrain air-water partitioning, thus bioavailability and fate, of the leaked fluid. This analysis quantifies the fraction of surfacing hydrocarbons that dissolves in the water column (∼33% by mass), the fraction that does not dissolve, and the fraction that evaporates promptly after surfacing (∼14% by mass). We do not quantify the leaked fraction lacking a surface expression; therefore, calculation of atmospheric mass fluxes provides a lower limit to the total hydrocarbon leak rate of 32,600 to 47,700 barrels of fluid per day, depending on reservoir fluid composition information. This study demonstrates a new approach for rapid-response airborne assessment of future oil spills. Copyright 2011 by the American Geophysical Union

A three dimensional model of the photosynthetic membranes of Ectothiorhodospira halochloris

The three dimensional organization of the complete photosynthetic apparatus of the extremely halophilic, bacteriochlorophyll b containing Ectothiorhodospira halochloris has been elaborated by several techniques of electron microscopy. Essentially all thylakoidal sacs are disc shaped and connected to the cytoplasmic membrane by small membraneous ldquobridgesrdquo. In sum, the lumina of all thylakoids (intrathylakoidal space) form one common periplasmic space. Thin sections confirm a paracrystalline arrangement of the photosynthetic complexes in situ. The ontogenic development of the photosynthetic apparatus is discussed based on a structural model derived from serial thin sections

Composite structural motifs of binding sites for delineating biological functions of proteins

Most biological processes are described as a series of interactions between proteins and other molecules, and interactions are in turn described in terms of atomic structures. To annotate protein functions as sets of interaction states at atomic resolution, and thereby to better understand the relation between protein interactions and biological functions, we conducted exhaustive all-against-all atomic structure comparisons of all known binding sites for ligands including small molecules, proteins and nucleic acids, and identified recurring elementary motifs. By integrating the elementary motifs associated with each subunit, we defined composite motifs which represent context-dependent combinations of elementary motifs. It is demonstrated that function similarity can be better inferred from composite motif similarity compared to the similarity of protein sequences or of individual binding sites. By integrating the composite motifs associated with each protein function, we define meta-composite motifs each of which is regarded as a time-independent diagrammatic representation of a biological process. It is shown that meta-composite motifs provide richer annotations of biological processes than sequence clusters. The present results serve as a basis for bridging atomic structures to higher-order biological phenomena by classification and integration of binding site structures.Comment: 34 pages, 7 figure

FLORA: a novel method to predict protein function from structure in diverse superfamilies

Predicting protein function from structure remains an active area of interest, particularly for the structural genomics initiatives where a substantial number of structures are initially solved with little or no functional characterisation. Although global structure comparison methods can be used to transfer functional annotations, the relationship between fold and function is complex, particularly in functionally diverse superfamilies that have evolved through different secondary structure embellishments to a common structural core. The majority of prediction algorithms employ local templates built on known or predicted functional residues. Here, we present a novel method (FLORA) that automatically generates structural motifs associated with different functional sub-families (FSGs) within functionally diverse domain superfamilies. Templates are created purely on the basis of their specificity for a given FSG, and the method makes no prior prediction of functional sites, nor assumes specific physico-chemical properties of residues. FLORA is able to accurately discriminate between homologous domains with different functions and substantially outperforms (a 2–3 fold increase in coverage at low error rates) popular structure comparison methods and a leading function prediction method. We benchmark FLORA on a large data set of enzyme superfamilies from all three major protein classes (α, β, αβ) and demonstrate the functional relevance of the motifs it identifies. We also provide novel predictions of enzymatic activity for a large number of structures solved by the Protein Structure Initiative. Overall, we show that FLORA is able to effectively detect functionally similar protein domain structures by purely using patterns of structural conservation of all residues

Isoforms of U1-70k control subunit dynamics in the human spliceosomal U1 snRNP

Most human protein-encoding genes contain multiple exons that are spliced together, frequently in alternative arrangements, by the spliceosome. It is established that U1 snRNP is an essential component of the spliceosome, in human consisting of RNA and ten proteins, several of which are post- translationally modified and exist as multiple isoforms. Unresolved and challenging to investigate are the effects of these post translational modifications on the dynamics, interactions and stability of the particle. Using mass spectrometry we investigate the composition and dynamics of the native human U1 snRNP and compare native and recombinant complexes to isolate the effects of various subunits and isoforms on the overall stability. Our data reveal differential incorporation of four protein isoforms and dynamic interactions of subunits U1-A, U1-C and Sm-B/B’. Results also show that unstructured post- ranslationally modified C-terminal tails are responsible for the dynamics of Sm-B/B’ and U1-C and that their interactions with the Sm core are controlled by binding to different U1-70k isoforms and their phosphorylation status in vivo. These results therefore provide the important functional link between proteomics and structure as well as insight into the dynamic quaternary structure of the native U1 snRNP important for its function.This work was funded by: BBSRC (OVM), BBSRC and EPSRC (HH and NM), EU Prospects (HH), European Science Foundation (NM), the Royal Society (CVR), and fellowship from JSPS and HFSP (YM and DAPK respectively)

Mathematical and Statistical Techniques for Systems Medicine: The Wnt Signaling Pathway as a Case Study

The last decade has seen an explosion in models that describe phenomena in systems medicine. Such models are especially useful for studying signaling pathways, such as the Wnt pathway. In this chapter we use the Wnt pathway to showcase current mathematical and statistical techniques that enable modelers to gain insight into (models of) gene regulation, and generate testable predictions. We introduce a range of modeling frameworks, but focus on ordinary differential equation (ODE) models since they remain the most widely used approach in systems biology and medicine and continue to offer great potential. We present methods for the analysis of a single model, comprising applications of standard dynamical systems approaches such as nondimensionalization, steady state, asymptotic and sensitivity analysis, and more recent statistical and algebraic approaches to compare models with data. We present parameter estimation and model comparison techniques, focusing on Bayesian analysis and coplanarity via algebraic geometry. Our intention is that this (non exhaustive) review may serve as a useful starting point for the analysis of models in systems medicine.Comment: Submitted to 'Systems Medicine' as a book chapte

Cytotoxicity, chemical stability, and surface properties of ferroelectric ceramics for biomaterials

© 2017 The American Ceramic Society Surface chemistry and topo-physical properties determine the interactions of biomaterials with their physiological environment. Ferroelectrics hold great promise as the next generation of scaffolds for tissue repair since they feature tunable surface electrical charges, piezoelectricity, and sensing capabilities. We investigate the topography, wettability, chemical stability, and cytotoxicity in salient ferroelectric systems such as (1−x) (Na1/2Bi1/2)TiO3–xBaTiO3, (1−x)Ba(Zr0.2Ti0.8)O3−x(Ba0.7Ca0.3)TiO3, and Pb(Zr,Ti)O3 to test their suitability as biomaterials. The lead-free ferroelectrics promote in vitro cell viability and proliferation to a considerably high extent. 0.94 mol % (Na1/2Bi1/2)TiO3–0.06 mol% BaTiO3 showed the greatest potential leading to a cell viability of (149 ± 30)% and DNA synthesis of (299 ± 85)% in comparison to the reference. Lead leaching from Pb(Zr,Ti)O3 negatively affected the cultured cells. Wettability and chemical stability are key factors that determine the cytotoxicity of ferroelectrics. These variables have to be considered in the design of novel electroactive scaffolds based on ferroelectric ceramics

Assessment of the multidisciplinary education for a major change in clinical practice; a prospective cohort study

Background: New approaches are often introduced to the neonatal intensive care unit (NICU) and other areas of the health service in either a haphazard or cataclysmic fashion. The needs of staff education are often addressed incompletely or too late. Rarely is education assessed after the introduction of a major change. We changed the basis of our NICU respiratory support. We conducted a major educational and support program before this intervention. This study documented and assessed the educational components of this change in our health service provision. Methods: Senior medical and nursing staff attended training abroad and an education program was applied for one year prior to the change. Multidisciplinary educational support for doctors, nurses and allied health was continued after the change. Assessment was by anonymous questionnaire, prior to change, at one and at nine months. Our hypothesis was that dissatisfaction with education would be greatest at one month. Results: Both theory education and practical education aspects of the new approach were rated as good to very good and this did not change with time. Difficulty of applying the technique was rated as ambivalent initially but decreased significantly over 9 months until it was rated easy to very easy (p < 0.001). Over all, the change was rated by staff as beneficial, both at the end of the education period and at nine months, with no decrease at one month. Conclusion: If education and training reaches all staff, with a system of mutual and continued support, even large changes in clinical practice can be achieved without the dissatisfaction with the educational process that is often otherwise seen