Microstructure, mechanical, and thermogravimetric characterization of cellulosic by-products obtained from biomass seeds

The microstructural, thermal, and nanomechanical characterization of biomass by-products coming from the food industry were studied. Scanning electron microscopy showed a microstructure formed by polygonal grains. The thermal behavior of seeds, evaluated by thermogravimetric analysis, revealed three main components (hemicellulose, cellulose, and lignin). Walnut shell showed the highest thermal stability and also the highest amount of lignin. The nanomechanical aspects were evaluated by nanoindentation. Samples with higher amount of cellulose presented minor modulus values. In accordance with the thermal stability, the highest modulus and hardness were observed in walnut. These by-products could be useful as reinforcement materials for biodegradable plastic industry.This work has been supported by the Spanish Ministry of Science and Innovation (MAT2011-28468-C02-02) and the Autonomous Government of Valencia (Spain) through the research program Geronimo Forteza (62/2010, 9 de Junio DOCV no 6291). M.P. Arrieta is granted by Santiago Grisolia program (GRISOLIA/2011/007).Rayón Encinas, E.; Ferrándiz Bou, S.; Rico Beneito, MI.; López Martínez, J.; Arrieta, MP. (2015). Microstructure, mechanical, and thermogravimetric characterization of cellulosic by-products obtained from biomass seeds. International Journal of Food Properties. 18(6):1211-1222. https://doi.org/10.1080/10942912.2014.884578S1211122218

Bionanocomposite films based on plasticized PLA PHB/cellulose nanocrystal blends

Optically transparent plasticized poly(lactic acid) (PLA) based bionanocomposite films intended for food packaging were prepared by melt blending. Materials were plasticized with 15 wt% of acetyl(tributyl citrate) (ATBC) to improve the material process ability and to obtain flexibile films. Poly(hydroxybutyrate) (PHB) was used to increase PLA crystallinity. The thermal stability of the PLA-PHB blends was improved by the addition of 5 wt% of cellulose nanocrystals (CNC) or modified cellulose nanocrystals (CNCs) synthesized from microcrystalline cellulose. The combination of ATBC and cellulose nanocrystals, mainly the better dispersed CNCs, improved the interaction between PLA and PHB. Thus, an improvement on the oxygen barrier and stretchability was achieved in PLA-PHB-CNCs-ATBC which also displayed somewhat UV light blocking effect. All bionanocomposite films presented appropriate disintegration in compost suggesting their possible applications as biodegradable packaging materials. (C) 2014 Elsevier Ltd. All rights reserved.Authors wish to acknowledge Spanish Ministry of Science and Innovation (MAT2011-28468-C02-01 and 02), Prof. A. Jimenez and Dr. Nuria Burgos (University of Alicante, Spain) for their assistance in OTR measurements and Gesenu S.p.a. for compost supply. M.P. Arrieta wishes to thank Generalitat Valenciana for Santiago Grisolia Fellowship (2011/007) and Universitat Politecnica de Valencia for the Development Support Programme PAID-00-12 (SP20120120).Arrieta, MP.; Fortunati, E.; Dominici, F.; López Martínez, J.; Kenny, JM. (2015). Bionanocomposite films based on plasticized PLA PHB/cellulose nanocrystal blends. Carbohydrate Polymers. (121):265-275. https://doi.org/10.1016/j.carbpol.2014.12.056S26527512

PLA-PHB/cellulose based films: Mechanical, barrier and disintegration properties

Nanocomposite films based on poly(lactic acid)-poly(hydroxybutyrate) (PLA-PHB) blends and synthesized cellulose nanocrystals (CNC) or surfactant modified cellulose nanocrystals (CNCs), as bio-based reinforcement, were prepared by melt extrusion followed by film forming. The obtained nanocomposites are intended for short-term food packaging. Thus, the mechanical, optical, barrier and wettability properties were studied. Functionalized CNCs contribute to enhance the interfacial adhesion between PLA and PHB, leading to improved mechanical stiffness and increased film stretchability. The synergic effects of the PHB and CNCs on the PLA barrier properties were confirmed by increases in oxygen barrier properties and reductions in surface wettability of the nanocomposites. In addition, the measurements of the viscosity molecular weight for ternary systems showed practically no degradation of PLA and smaller degradation of PHB during processing due to nanocrystal presence. The disintegration process in composting conditions of PLA was delayed by the addition of PHB, while CNC speeded it up. PLA-PHB-CNCs formulations showed enhanced mechanical performance, improved water resistance, reduced oxygen and UV-light transmission, as well as appropriate disintegration in compost suggesting possible applications as packaging materials. (C) 2014 Elsevier Ltd. All rights reserved.This research was supported by the Ministry of Science and Innovation of Spain (MAT2011-28468-C02-01 and MAT2011-28468-C02-02). M.P. Arrieta thanks Generalitat Valenciana (Spain) for Santiago Grisolia Fellowship (GRISOLIA/2011/007) and Universitat Politecnica de Valencia for the Development Support Programme PAID-00-12 (SP20120120). The Authors acknowledge Gesenu S.p.a. for compost supply. Authors gratefully thank Prof. Alfonso Jimenez (University of Alicante, Spain) and Prof. Maria Dolores Salvador Moya (Universitat Politecnica de Valencia) for their assistance with OTR measurements and optical microscope-EDF measurements, respectively.Arrieta, MP.; Fortunati, E.; Dominici, F.; Rayón Encinas, E.; López Martínez, J.; Kenny, JM. (2014). PLA-PHB/cellulose based films: Mechanical, barrier and disintegration properties. Polymer Degradation and Stability. 107:139-149. https://doi.org/10.1016/j.polymdegradstab.2014.05.010S13914910

Does Ad Hoc Coronary Intervention Reduce Radiation Exposure? – Analysis of 568 Patients

Background:Advantages and disadvantages of ad hoc percutaneous coronary intervention have been described. However little is known about the radiation exposure of that procedure as compared with the staged intervention.Objective:To compare the radiation dose of the ad hoc percutaneous coronary intervention with that of the staged procedureMethods:The dose-area product and total Kerma were measured, and the doses of the diagnostic and therapeutic procedures were added. In addition, total fluoroscopic time and number of acquisitions were evaluated.Results:A total of 568 consecutive patients were treated with ad hoc percutaneous coronary intervention (n = 320) or staged percutaneous coronary intervention (n = 248). On admission, the ad hoc group had less hypertension (74.1% vs 81.9%; p = 0.035), dyslipidemia (57.8% vs. 67.7%; p = 0.02) and three-vessel disease (38.8% vs. 50.4%; p = 0.015). The ad hoc group was exposed to significantly lower radiation doses, even after baseline characteristic adjustment between both groups. The ad hoc group was exposed to a total dose-area product of 119.7 ± 70.7 Gycm2, while the staged group, to 139.2 ± 75.3 Gycm2 (p < 0.001).Conclusion:Ad hoc percutaneous coronary intervention reduced radiation exposure as compared with diagnostic and therapeutic procedures performed at two separate times

Conway’s Question: The Chase for Completeness

We study various degrees of completeness for a Tychonoff space X. One of them plays a central role, namely X is called a Conway space if X is sequentially closed in its Stone–Čech compactification β X (a prominent example of Conway spaces is provided by Dieudonné complete spaces). The Conway spaces constitute a bireflective subcategory Conw of the category Tych of Tychonoff spaces. Replacing sequential closure by the general notion of a closure operator C, we introduce analogously the subcategory Conw C of C-Conway spaces, that turns out to be again a bireflective subcategory of Tych. We show that every bireflective subcategory of Tych can be presented in this way by building a Galois connection between bireflective subcategories of Tych and closure operators of Top finer than the Kuratowski closure. Other levels of completeness are considered for the (underlying topological spaces of) topological groups. A topological group G is sequentially complete if it is sequentially closed in its Raĭkov completion . The sequential completeness for topological groups is stronger than Conway’s property, although they coincide in some classes of topological groups, for example: free (Abelian) topological groups, pseudocompact groups, etc