Study of the Influence of the Reprocessing Cycles on the Final Properties of Polylactide Pieces Obtained by Injection Molding

[EN] This research work aims to study the influence of the reprocessing cycles on the mechanical, thermal, and thermomechanical properties of polylactide (PLA). To this end, PLA was subjected to as many as six extrusion cycles and the resultant pellets were shaped into pieces by injection molding. Mechanical characterization revealed that the PLA pieces presented relatively similar properties up to the third reprocessing cycle, whereas further cycles induced an intense reduction in ductility and toughness. The effect of the reprocessing cycles was also studied by the changes in the melt fluidity, which showed a significant increase after four reprocessing cycles. An increase in the bio-polyester chain mobility was also attained with the number of the reprocessing cycles that subsequently favored an increase in crystallinity of PLA. A visual inspection indicated that PLA developed certain yellowing and the pieces also became less transparent with the increasing number of reprocessing cycles. Therefore, the obtained results showed that PLA suffers a slight degradation after one or two reprocessing cycles whereas performance impairment becomes more evident above the fourth reprocessing cycle. This finding suggests that the mechanical recycling of PLA for up to three cycles of extrusion and subsequent injection molding is technically feasible.This research was funded by the Spanish Ministry of Science, Innovation, and Universities (MICIU) project numbers MAT2017-84909-C2-2-R and AGL2015-63855-C2-1-R. L. Quiles-Carrillo wants to thank GV for his FPI grant (ACIF/2016/182) and MECD for his FPU grant (FPU15/03812). D. Lascano wants to thank UPV for the grant received through the PAID-01-18 program. S. Torres-Giner is recipient of a Juan de la Cierva¿ Incorporación contract (IJCI-2016-29675) from MICIU. Microscopy services at UPV are acknowledged for their help in collecting and analyzing FESEM images.Agüero, Á.; Morcillo, MDC.; Quiles-Carrillo, L.; Balart, R.; Boronat, T.; Lascano-Aimacaña, DS.; Torres-Giner, S.... (2019). Study of the Influence of the Reprocessing Cycles on the Final Properties of Polylactide Pieces Obtained by Injection Molding. Polymers. 11(12):1-20. https://doi.org/10.3390/polym11121908S1201112Gironi, F., & Piemonte, V. (2010). Life cycle assessment of polylactic acid and polyethylene terephthalate bottles for drinking water. Environmental Progress & Sustainable Energy, 30(3), 459-468. doi:10.1002/ep.10490Hoppe, W., Thonemann, N., & Bringezu, S. (2017). Life Cycle Assessment of Carbon Dioxide-Based Production of Methane and Methanol and Derived Polymers. Journal of Industrial Ecology, 22(2), 327-340. doi:10.1111/jiec.12583Luján-Ornelas, C., Mancebo del C. Sternenfels, U., & Güereca, L. P. (2018). Life cycle assessment of Mexican polymer and high-durability cotton paper banknotes. Science of The Total Environment, 630, 409-421. doi:10.1016/j.scitotenv.2018.02.177Vidal, R., Moliner, E., Martin, P. P., Fita, S., Wonneberger, M., Verdejo, E., … González, A. (2017). Life Cycle Assessment of Novel Aircraft Interior Panels Made from Renewable or Recyclable Polymers with Natural Fiber Reinforcements and Non-Halogenated Flame Retardants. Journal of Industrial Ecology, 22(1), 132-144. doi:10.1111/jiec.12544Kijchavengkul, T., Auras, R., Rubino, M., Selke, S., Ngouajio, M., & Fernandez, R. T. (2010). Biodegradation and hydrolysis rate of aliphatic aromatic polyester. Polymer Degradation and Stability, 95(12), 2641-2647. doi:10.1016/j.polymdegradstab.2010.07.018Borovikov, P. I., Sviridov, A. P., Antonov, E. N., Dunaev, A. G., Krotova, L. I., Fatkhudinov, T. K., & Popov, V. K. (2019). Model of aliphatic polyesters hydrolysis comprising water and oligomers diffusion. Polymer Degradation and Stability, 159, 70-78. doi:10.1016/j.polymdegradstab.2018.11.017Han, S.-I., Yoo, Y., Kim, D. K., & Im, S. S. (2004). Biodegradable Aliphatic Polyester Ionomers. Macromolecular Bioscience, 4(3), 199-207. doi:10.1002/mabi.200300095Li, Y., Liao, C., & Tjong, S. C. (2019). Synthetic Biodegradable Aliphatic Polyester Nanocomposites Reinforced with Nanohydroxyapatite and/or Graphene Oxide for Bone Tissue Engineering Applications. Nanomaterials, 9(4), 590. doi:10.3390/nano9040590Sekiguchi, T., Saika, A., Nomura, K., Watanabe, T., Watanabe, T., Fujimoto, Y., … Kanehiro, H. (2011). Biodegradation of aliphatic polyesters soaked in deep seawaters and isolation of poly(ɛ-caprolactone)-degrading bacteria. Polymer Degradation and Stability, 96(7), 1397-1403. doi:10.1016/j.polymdegradstab.2011.03.004Ferrero, B., Fombuena, V., Fenollar, O., Boronat, T., & Balart, R. (2014). Development of natural fiber-reinforced plastics (NFRP) based on biobased polyethylene and waste fibers from Posidonia oceanica seaweed. Polymer Composites, 36(8), 1378-1385. doi:10.1002/pc.23042Montanes, N., Garcia-Sanoguera, D., Segui, V. J., Fenollar, O., & Boronat, T. (2017). Processing and Characterization of Environmentally Friendly Composites from Biobased Polyethylene and Natural Fillers from Thyme Herbs. Journal of Polymers and the Environment, 26(3), 1218-1230. doi:10.1007/s10924-017-1025-2Torres-Giner, S., Torres, A., Ferrándiz, M., Fombuena, V., & Balart, R. (2017). Antimicrobial activity of metal cation-exchanged zeolites and their evaluation on injection-molded pieces of bio-based high-density polyethylene. Journal of Food Safety, 37(4), e12348. doi:10.1111/jfs.12348Quiles-Carrillo, L., Boronat, T., Montanes, N., Balart, R., & Torres-Giner, S. (2019). Injection-molded parts of fully bio-based polyamide 1010 strengthened with waste derived slate fibers pretreated with glycidyl- and amino-silane coupling agents. Polymer Testing, 77, 105875. doi:10.1016/j.polymertesting.2019.04.022Quiles-Carrillo, L., Montanes, N., Boronat, T., Balart, R., & Torres-Giner, S. (2017). Evaluation of the engineering performance of different bio-based aliphatic homopolyamide tubes prepared by profile extrusion. Polymer Testing, 61, 421-429. doi:10.1016/j.polymertesting.2017.06.004Abedini, F., Ebrahimi, M., Roozbehani, A. H., Domb, A. J., & Hosseinkhani, H. (2018). Overview on natural hydrophilic polysaccharide polymers in drug delivery. Polymers for Advanced Technologies, 29(10), 2564-2573. doi:10.1002/pat.4375Gandini, A., Lacerda, T. M., Carvalho, A. J. F., & Trovatti, E. (2015). Progress of Polymers from Renewable Resources: Furans, Vegetable Oils, and Polysaccharides. Chemical Reviews, 116(3), 1637-1669. doi:10.1021/acs.chemrev.5b00264Jagadeesh, D., Kanny, K., & Prashantha, K. (2015). A review on research and development of green composites from plant protein-based polymers. Polymer Composites, 38(8), 1504-1518. doi:10.1002/pc.23718Rai, K., Sun, Y., Shaliutina-Kolesova, A., Nian, R., & Xian, M. (2018). Proteins: Natural Polymers for Tissue Engineering. Journal of Biomaterials and Tissue Engineering, 8(3), 295-308. doi:10.1166/jbt.2018.1753Werten, M. W. T., Eggink, G., Cohen Stuart, M. A., & de Wolf, F. A. (2019). Production of protein-based polymers in Pichia pastoris. Biotechnology Advances, 37(5), 642-666. doi:10.1016/j.biotechadv.2019.03.012Elmowafy, E., Abdal-Hay, A., Skouras, A., Tiboni, M., Casettari, L., & Guarino, V. (2019). Polyhydroxyalkanoate (PHA): applications in drug delivery and tissue engineering. Expert Review of Medical Devices, 16(6), 467-482. doi:10.1080/17434440.2019.1615439Partini, M., & Pantani, R. (2007). FTIR analysis of hydrolysis in aliphatic polyesters. Polymer Degradation and Stability, 92(8), 1491-1497. doi:10.1016/j.polymdegradstab.2007.05.009Wang, D. K., Varanasi, S., Fredericks, P. M., Hill, D. J. T., Symons, A. L., Whittaker, A. K., & Rasoul, F. (2013). FT-IR characterization and hydrolysis of PLA-PEG-PLA based copolyester hydrogels with short PLA segments and a cytocompatibility study. Journal of Polymer Science Part A: Polymer Chemistry, 51(24), 5163-5176. doi:10.1002/pola.26930Li, Y., Chu, Z., Li, X., Ding, X., Guo, M., Zhao, H., … Fan, Y. (2017). The effect of mechanical loads on the degradation of aliphatic biodegradable polyesters. Regenerative Biomaterials, 4(3), 179-190. doi:10.1093/rb/rbx009Quiles-Carrillo, L., Duart, S., Montanes, N., Torres-Giner, S., & Balart, R. (2018). Enhancement of the mechanical and thermal properties of injection-molded polylactide parts by the addition of acrylated epoxidized soybean oil. Materials & Design, 140, 54-63. doi:10.1016/j.matdes.2017.11.031Quiles-Carrillo, L., Montanes, N., Garcia-Garcia, D., Carbonell-Verdu, A., Balart, R., & Torres-Giner, S. (2018). Effect of different compatibilizers on injection-molded green composite pieces based on polylactide filled with almond shell flour. Composites Part B: Engineering, 147, 76-85. doi:10.1016/j.compositesb.2018.04.017Yanfang, C., Jiayi, X., Qinggang, T., Zhenlei, Z., Jun, Z., Xiaoyan, X., & Yan, L. (2019). End-Group Functionalization of Polyethylene Glycol-Polylactic Acid Copolymer and Its Application in the Field of Pharmaceutical Carriers. Journal of Biobased Materials and Bioenergy, 13(5), 690-698. doi:10.1166/jbmb.2019.1900Nguyen, T.-H., Tangboriboonrat, P., Rattanasom, N., Petchsuk, A., Opaprakasit, M., Thammawong, C., & Opaprakasit, P. (2011). Polylactic acid/ethylene glycol triblock copolymer as novel crosslinker for epoxidized natural rubber. Journal of Applied Polymer Science, 124(1), 164-174. doi:10.1002/app.35088Sun, R., Du, X.-J., Sun, C.-Y., Shen, S., Liu, Y., Yang, X.-Z., … Wang, J. (2015). A block copolymer of zwitterionic polyphosphoester and polylactic acid for drug delivery. Biomaterials Science, 3(7), 1105-1113. doi:10.1039/c4bm00430bAnjos, A. L. V. dos, Perez, R. C., Braga, B. M., Matsumoto, M. A., Okamoto, R. O., Saraiva, P. P., … Pegoraro, T. A. (2017). Polylactic/polyglycolic acid copolymer is a good carrier for bmp-2 on bone regeneration? Bioscience Journal, 815-823. doi:10.14393/bj-v33n3-38449Fairag, R., Rosenzweig, D. H., Ramirez-Garcialuna, J. L., Weber, M. H., & Haglund, L. (2019). Three-Dimensional Printed Polylactic Acid Scaffolds Promote Bone-like Matrix Deposition in Vitro. ACS Applied Materials & Interfaces, 11(17), 15306-15315. doi:10.1021/acsami.9b02502Miclaus, R., Repanovici, A., & Roman, N. (2017). Biomaterials: Polylactic Acid and 3D Printing Processes for Orthosis and Prosthesis. Materiale Plastice, 54(1), 98-102. doi:10.37358/mp.17.1.4794Zhang, H., Mao, X., Zhao, D., Jiang, W., Du, Z., Li, Q., … Han, D. (2017). Three dimensional printed polylactic acid-hydroxyapatite composite scaffolds for prefabricating vascularized tissue engineered bone: An in vivo bioreactor model. Scientific Reports, 7(1). doi:10.1038/s41598-017-14923-7Coulembier, O., Degée, P., Hedrick, J. L., & Dubois, P. (2006). From controlled ring-opening polymerization to biodegradable aliphatic polyester: Especially poly(β-malic acid) derivatives. Progress in Polymer Science, 31(8), 723-747. doi:10.1016/j.progpolymsci.2006.08.004Mazzanti, V., Malagutti, L., & Mollica, F. (2019). FDM 3D Printing of Polymers Containing Natural Fillers: A Review of their Mechanical Properties. Polymers, 11(7), 1094. doi:10.3390/polym11071094Zhao, P., Rao, C., Gu, F., Sharmin, N., & Fu, J. (2018). Close-looped recycling of polylactic acid used in 3D printing: An experimental investigation and life cycle assessment. Journal of Cleaner Production, 197, 1046-1055. doi:10.1016/j.jclepro.2018.06.275Liu, Z., Wang, Y., Wu, B., Cui, C., Guo, Y., & Yan, C. (2019). A critical review of fused deposition modeling 3D printing technology in manufacturing polylactic acid parts. The International Journal of Advanced Manufacturing Technology, 102(9-12), 2877-2889. doi:10.1007/s00170-019-03332-xMatos, B. D. M., Rocha, V., da Silva, E. J., Moro, F. H., Bottene, A. C., Ribeiro, C. A., … Silva Barud, H. da. (2018). Evaluation of commercially available polylactic acid (PLA) filaments for 3D printing applications. Journal of Thermal Analysis and Calorimetry, 137(2), 555-562. doi:10.1007/s10973-018-7967-3Kamthai, S., & Magaraphan, R. (2018). Development of an active polylactic acid (PLA) packaging film by adding bleached bagasse carboxymethyl cellulose (CMCB) for mango storage life extension. Packaging Technology and Science, 32(2), 103-116. doi:10.1002/pts.2420Marra, A., Silvestre, C., Duraccio, D., & Cimmino, S. (2016). Polylactic acid/zinc oxide biocomposite films for food packaging application. International Journal of Biological Macromolecules, 88, 254-262. doi:10.1016/j.ijbiomac.2016.03.039Masmoudi, F., Bessadok, A., Dammak, M., Jaziri, M., & Ammar, E. (2016). Biodegradable packaging materials conception based on starch and polylactic acid (PLA) reinforced with cellulose. Environmental Science and Pollution Research, 23(20), 20904-20914. doi:10.1007/s11356-016-7276-yÅkesson, D., Vrignaud, T., Tissot, C., & Skrifvars, M. (2016). Mechanical Recycling of PLA Filled with a High Level of Cellulose Fibres. Journal of Polymers and the Environment, 24(3), 185-195. doi:10.1007/s10924-016-0760-0Cristina, A. M., Sara, F., Fausto, G., Vincenzo, P., Rocchina, S., & Claudio, V. (2018). Degradation of Post-consumer PLA: Hydrolysis of Polymeric Matrix and Oligomers Stabilization in Aqueous Phase. Journal of Polymers and the Environment, 26(12), 4396-4404. doi:10.1007/s10924-018-1312-6Karst, D., & Yang, Y. (2006). Molecular modeling study of the resistance of PLA to hydrolysis based on the blending of PLLA and PDLA. Polymer, 47(13), 4845-4850. doi:10.1016/j.polymer.2006.05.002Najafi, N., Heuzey, M. C., & Carreau, P. J. (2012). Crystallization behavior and morphology of polylactide and PLA/clay nanocomposites in the presence of chain extenders. Polymer Engineering & Science, 53(5), 1053-1064. doi:10.1002/pen.23355Palsikowski, P. A., Kuchnier, C. N., Pinheiro, I. F., & Morales, A. R. (2017). Biodegradation in Soil of PLA/PBAT Blends Compatibilized with Chain Extender. Journal of Polymers and the Environment, 26(1), 330-341. doi:10.1007/s10924-017-0951-3Stloukal, P., Kalendova, A., Mattausch, H., Laske, S., Holzer, C., & Koutny, M. (2015). The influence of a hydrolysis-inhibiting additive on the degradation and biodegradation of PLA and its nanocomposites. Polymer Testing, 41, 124-132. doi:10.1016/j.polymertesting.2014.10.015Tanaka, M., Atsumi, K., Onodera, M., Saito, H., & Kimpara, I. (2014). Hydrolysis control by introduction of photodissociable protecting groups in PLA as matrix of green composite materials. Advanced Composite Materials, 23(5-6), 521-534. doi:10.1080/09243046.2014.915117Åkesson, D., Fazelinejad, S., Skrifvars, V.-V., & Skrifvars, M. (2016). Mechanical recycling of polylactic acid composites reinforced with wood fibres by multiple extrusion and hydrothermal ageing. Journal of Reinforced Plastics and Composites, 35(16), 1248-1259. doi:10.1177/0731684416647507Fazelinejad, S., Åkesson, D., & Skrifvars, M. (2017). Repeated Mechanical Recycling of Polylactic Acid Filled with Chalk. Progress in Rubber, Plastics and Recycling Technology, 33(1), 1-16. doi:10.1177/147776061703300101Hamad, K., Kaseem, M., & Deri, F. (2010). Effect of recycling on rheological and mechanical properties of poly(lactic acid)/polystyrene polymer blend. Journal of Materials Science, 46(9), 3013-3019. doi:10.1007/s10853-010-5179-8Baimark, Y., & Srihanam, P. (2015). Influence of chain extender on thermal properties and melt flow index of stereocomplex PLA. Polymer Testing, 45, 52-57. doi:10.1016/j.polymertesting.2015.04.017Freitas, A. L. P. de L., Tonini Filho, L. R., Calvão, P. S., & Souza, A. M. C. de. (2017). Effect of montmorillonite and chain extender on rheological, morphological and biodegradation behavior of PLA/PBAT blends. Polymer Testing, 62, 189-195. doi:10.1016/j.polymertesting.2017.06.030Hachana, N., Wongwanchai, T., Chaochanchaikul, K., & Harnnarongchai, W. (2016). Influence of Crosslinking Agent and Chain Extender on Properties of Gamma-Irradiated PLA. Journal of Polymers and the Environment, 25(2), 323-333. doi:10.1007/s10924-016-0812-5Tochacek, J., & Jancar, J. (2012). Processing degradation index (PDI) – A quantitative measure of processing stability of polypropylene. Polymer Testing, 31(8), 1115-1120. doi:10.1016/j.polymertesting.2012.08.004Gonzalez, L., Agüero, A., Quiles-Carrillo, L., Lascano, D., & Montanes, N. (2019). Optimization of the Loading of an Environmentally Friendly Compatibilizer Derived from Linseed Oil in Poly(Lactic Acid)/Diatomaceous Earth Composites. Materials, 12(10), 1627. doi:10.3390/ma12101627Stencel, R., Kasperski, J., Pakieła, W., Mertas, A., Bobela, E., Barszczewska-Rybarek, I., & Chladek, G. (2018). Properties of Experimental Dental Composites Containing Antibacterial Silver-Releasing Filler. Materials, 11(6), 1031. doi:10.3390/ma11061031Simmons, H., & Kontopoulou, M. (2018). Hydrolytic degradation of branched PLA produced by reactive extrusion. Polymer Degradation and Stability, 158, 228-237. doi:10.1016/j.polymdegradstab.2018.11.006Oromiehie, A., & Mamizadeh, A. (2004). Recycling PET beverage bottles and improving properties. Polymer International, 53(6), 728-732. doi:10.1002/pi.1389Ferri, J. M., Fenollar, O., Jorda-Vilaplana, A., García-Sanoguera, D., & Balart, R. (2016). Effect of miscibility on mechanical and thermal properties of poly(lactic acid)/ polycaprolactone blends. Polymer International, 65(4), 453-463. doi:10.1002/pi.5079Ferri, J. M., Garcia-Garcia, D., Montanes, N., Fenollar, O., & Balart, R. (2017). The effect of maleinized linseed oil as biobased plasticizer in poly(lactic acid)-based formulations. Polymer International, 66(6), 882-891. doi:10.1002/pi.5329Lascano, D., Quiles-Carrillo, L., Balart, R., Boronat, T., & Montanes, N. (2019). Toughened Poly(Lactic Acid)—PLA Formulations by Binary Blends with Poly(Butylene Succinate-co-Adipate)—PBSA and Their Shape Memory Behaviour. Materials, 12(4), 622. doi:10.3390/ma12040622Yarahmadi, N., Jakubowicz, I., & Enebro, J. (2016). Polylactic acid and its blends with petroleum-based resins: Effects of reprocessing and recycling on properties. Journal of Applied Polymer Science, 133(36). doi:10.1002/app.43916Qi, H. J., Joyce, K., & Boyce, M. C. (2003). Durometer Hardness and the Stress-Strain Behavior of Elastomeric Materials. Rubber Chemistry and Technology, 76(2), 419-435. doi:10.5254/1.3547752Graupner, N., Albrecht, K., Ziegmann, G., Enzler, H., & Muessig, J. (2016). Influence of reprocessing on fibre length distribution, tensile strength and impact strength of injection moulded cellulose fibre-reinforced polylactide (PLA) composites. Express Polymer Letters, 10(8), 647-663. doi:10.3144/expresspolymlett.2016.59Awale, R., Ali, F., Azmi, A., Puad, N., Anuar, H., & Hassan, A. (2018). Enhanced Flexibility of Biodegradable Polylactic Acid/Starch Blends Using Epoxidized Palm Oil as Plasticizer. Polymers, 10(9), 977. doi:10.3390/polym10090977Sharma, S., Singh, A. A., Majumdar, A., & Butola, B. S. (2019). Tailoring the mechanical and thermal properties of polylactic acid-based bionanocomposite films using halloysite nanotubes and polyethylene glycol by solvent casting process. Journal of Materials Science, 54(12), 8971-8983. doi:10.1007/s10853-019-03521-9Tocháček, J., Jančář, J., Kalfus, J., Zbořilová, P., & Buráň, Z. (2008). Degradation of polypropylene impact-copolymer during processing. Polymer Degradation and Stability, 93(4), 770-775. doi:10.1016/j.polymdegradstab.2008.01.027La Mantia, F. P., & Correnti, A. (2003). Effect of Processing Conditions on the Degradation and on the Recycling of Polycarbonate. Progress in Rubber, Plastics and Recycling Technology, 19(3), 135-142. doi:10.1177/147776060301900301Papageorgiou, G. Z., Beslikas, T., Gigis, J., Christoforides, J., & Bikiaris, D. N. (2010). Crystallization and enzymatic hydrolysis of PLA grade for orthopedics. Advances in Polymer Technology, 29(4), 280-299. doi:10.1002/adv.20194Aguero, A., Quiles‐Carrillo, L., Jorda‐Vilaplana, A., Fenollar, O., & Montanes, N. (2019). Effect of different compatibilizers on environmentally friendly composites from poly(lactic acid) and diatomaceous earth. Polymer International, 68(5), 893-903. doi:10.1002/pi.5779Signori, F., Coltelli, M.-B., & Bronco, S. (2009). Thermal degradation of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) and their blends upon melt processing. Polymer Degradation and Stability, 94(1), 74-82. doi:10.1016/j.polymdegradstab.2008.10.004Yousif, E., & Haddad, R. (2013). Photodegradation and photostabilization of polymers, especially polystyrene: review. SpringerPlus, 2(1). doi:10.1186/2193-1801-2-398Carrasco, F., Pagès, P., Gámez-Pérez, J., Santana, O. O., & Maspoch, M. L. (2010). Processing of poly(lactic acid): Characterization of chemical structure, thermal stability and mechanical properties. Polymer Degradation and Stability, 95(2), 116-125. doi:10.1016/j.polymdegradstab.2009.11.045Garancher, J.-P., & Fernyhough, A. (2014). Expansion and dimensional stability of semi-crystalline polylactic acid foams. Polymer Degradation and Stability, 100, 21-28. doi:10.1016/j.polymdegradstab.2013.12.03

Evaluating Person-Centred Integrated Care to People with Complex Chronic Conditions: Early Implementation Results of the ProPCC Programme

Introduction: The evaluation of integrated care programmes for high-need high-cost older people is a challenge. We aim to share the early implementation results of the ProPCC programme in the North-Barcelona metropolitan area, in Catalonia, Spain. Methods: We analysed the intervention with retrospective data from May 2018 to December 2021 by describing the cohort complexity and by showing its 6-months pre-post impact on time spent at home and resources used: primary care visits, emergency department visits, hospital admissions and hospital stay. Findings: 264 cases were included (91% at home; 9% in nursing homes). 6-month pre vs. 6-months post results were (mean, p-value): primary care visits 8.2 vs. 11.5 (p < 0.05); emergency department visits 1.4 vs. 0.9 (p < 0.05); hospital admissions 0.7 vs. 0.5 (p < 0.05); hospital stay 12.8 vs. 7.9 days (p < 0.05). Time spent at home was 169.2 vs.174.2 days (p < 0.05). Conclusion: Early implementation of the ProPCC programme results in an increase in time spent at home (up to 3%) and significant reductions in emergency department attendance (–37.2%) and hospital stays (–38.3%). The increased use of primary care resources is compensated by the hospital resources savings, with a result in the average total cost of –46.3%

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Efecto de Nanotubos de Halloysita en las propiedades Retardantes a la llama en Biopoliamida 610

[ES] El principal objetivo del trabajo es el análisis de nanotubos de halloysita (HNTs) de relleno como retardante de llama natural en biopoliamida 610 (PA610). Los HNT son arcillas naturales con forma de nanotubos. La incorporación de los HNT en la matriz PA610 conduce a una reducción tanto de la densidad óptica como a una reducción significativa del número de gases tóxicos emitidos durante la combustión. Esta mejora en las propiedades contra incendios es relevante en aplicaciones donde se requiere seguridad contra incendios. En cuanto a los resultados del cono calorimétrico, la incorporación de 30% de HNT consiguió una reducción significativa en cuanto a los valores máximos obtenidos de la tasa de liberación de calor (HRR) y modificando directamente la forma de la curva característica. Esta mejora en el calor liberado ha producido un retraso en la transferencia de masa de los productos de descomposición volátiles. Sin embargo, en relación al tiempo de ignición de las muestras (TTI), la incorporación de HNTs reduce el tiempo de inicio de ignición. Los resultados indican que es posible obtener formulaciones poliméricas con un alto contenido renovable como PA610, y un relleno inorgánico natural en forma de nanotubo, es decir, HNT, con buenas propiedades ignífugas.Marset, D.; Morcillo, MDC.; Sanchez-Nacher, L.; Quiles-Carrillo, L. (2021). Efecto de Nanotubos de Halloysita en las propiedades Retardantes a la llama en Biopoliamida 610. Compobell. 61-64. http://hdl.handle.net/10251/191356616

Th22 response induced by Mycobacterium tuberculosis strains is closely related to severity of pulmonary lesions and bacillary load in patients with multi-drug-resistant tuberculosis

The role of interleukin-22 (IL-22) in the pathogenesis or tissue repair in human tuberculosis (TB) remains to be established. Here, we aimed to explore the ex-vivo and in-vitro T helper 22 (Th22) response in TB patients and healthy donors (HD) induced by different local multi-drug-resistant (MDR) Mvcobacterium tuberculosis (Mtb) strains. For this purpose, peripheral blood mononuclear cells from drug-susceptible (S-TB) MDR-TB patients and HD were stimulated with local MDR strains and the laboratory strain H37Rv. IL-22 and IL-17 expression and senescent status were assessed in CD4+ and CD8+ cells by flow cytometry, while IL-22 amount was measured in plasma and culture supernatants by enzyme-linked immunosorbent assay (ELISA). We found lower IL-22 amounts in plasma from TB patients than HD, together with a decrease in the number of circulating T cells expressing IL-22. In a similar manner, all Mtb strains enhanced IL-22 secretion and expanded IL-22+ cells within CD4+ and CD8+ subsets, being the highest levels detected in S-TB patients. In MDRTB, low systemic and Mtb-induced Th22 responses associated with high sputum bacillary load and bilateralism of lung lesions, suggesting that Th22 response could be influencing the ability of MDR-TB patients to control bacillary growth and tissue damage. In addition, in MDR-TB patients we observed that the higher the percentage of IL-22+ cells, the lower the proportion of programmed cell death 1 (PD-1)+ or CD57+ T cells. Furthermore, the highest proportion of senescent T cells was associated with severe lung lesions and bacillary load. Thus, T cell senescence would markedly influence Th22 response mounted by MDR-TB patients.Fil: Imperiale, Belén Rocío. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: García, Ana. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; ArgentinaFil: Minotti, Alejandro Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: González Montaner, Pablo. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; ArgentinaFil: Moracho Lucila. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; ArgentinaFil: Morcillo, N.. Provincia de Buenos Aires. Ministerio de Salud. Hospital ; ArgentinaFil: Palmero, Domingo Juan. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; ArgentinaFil: Sasiain, Maria del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: de la Barrera, Silvia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin

SFRPs act as negative modulators of ADAM10 to regulate retinal neurogenesis

10.1038/nn.2794Nature Neuroscience145562-570NANE

Role of age and comorbidities in mortality of patients with infective endocarditis.

The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups: A total of 3120 patients with IE (1327  There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in th

Contemporary use of cefazolin for MSSA infective endocarditis: analysis of a national prospective cohort

Objectives: This study aimed to assess the real use of cefazolin for methicillin-susceptible Staphylococcus aureus (MSSA) infective endocarditis (IE) in the Spanish National Endocarditis Database (GAMES) and to compare it with antistaphylococcal penicillin (ASP). Methods: Prospective cohort study with retrospective analysis of a cohort of MSSA IE treated with cloxacillin and/or cefazolin. Outcomes assessed were relapse; intra-hospital, overall, and endocarditis-related mortality; and adverse events. Risk of renal toxicity with each treatment was evaluated separately. Results: We included 631 IE episodes caused by MSSA treated with cloxacillin and/or cefazolin. Antibiotic treatment was cloxacillin, cefazolin, or both in 537 (85%), 57 (9%), and 37 (6%) episodes, respectively. Patients treated with cefazolin had significantly higher rates of comorbidities (median Charlson Index 7, P <0.01) and previous renal failure (57.9%, P <0.01). Patients treated with cloxacillin presented higher rates of septic shock (25%, P = 0.033) and new-onset or worsening renal failure (47.3%, P = 0.024) with significantly higher rates of in-hospital mortality (38.5%, P = 0.017). One-year IE-related mortality and rate of relapses were similar between treatment groups. None of the treatments were identified as risk or protective factors. Conclusion: Our results suggest that cefazolin is a valuable option for the treatment of MSSA IE, without differences in 1-year mortality or relapses compared with cloxacillin, and might be considered equally effective

Prevalence and Etiology of Community-acquired Pneumonia in Immunocompromised Patients

BACKGROUND: The correct management of immunocompromised patients with pneumonia is debated. We evaluated the prevalence, risk factors, and characteristics of immunocompromised patients coming from the community with pneumonia. METHODS: We conducted a secondary analysis of an international, multicenter study enrolling adult patients coming from the community with pneumonia and hospitalized in 222 hospitals in 54 countries worldwide. Risk factors for immunocompromise included AIDS, aplastic anemia, asplenia, hematological cancer, chemotherapy, neutropenia, biological drug use, lung transplantation, chronic steroid use, and solid tumor. RESULTS: At least 1 risk factor for immunocompromise was recorded in 18% of the 3702 patients enrolled. The prevalences of risk factors significantly differed across continents and countries, with chronic steroid use (45%), hematological cancer (25%), and chemotherapy (22%) the most common. Among immunocompromised patients, community-acquired pneumonia (CAP) pathogens were the most frequently identified, and prevalences did not differ from those in immunocompetent patients. Risk factors for immunocompromise were independently associated with neither Pseudomonas aeruginosa nor non-community-acquired bacteria. Specific risk factors were independently associated with fungal infections (odds ratio for AIDS and hematological cancer, 15.10 and 4.65, respectively; both P = .001), mycobacterial infections (AIDS; P = .006), and viral infections other than influenza (hematological cancer, 5.49; P &lt; .001). CONCLUSIONS: Our findings could be considered by clinicians in prescribing empiric antibiotic therapy for CAP in immunocompromised patients. Patients with AIDS and hematological cancer admitted with CAP may have higher prevalences of fungi, mycobacteria, and noninfluenza viruses