Cells interact mechanically with their environment, exerting mechanical forces that probe the extracellular matrix (ECM). The mechanical properties of the ECM determine cell behavior and control cell differentiation both in 2D and 3D environments. Gelatin (Gel) is a soft hydrogel into which cells can be embedded. This study shows signifi cant 3D Gel shrinking due to the high traction cellular forces exerted by the cells on the matrix, which prevents cell differentiation. To modulate this process, Gel with hyaluronic acid (HA) has been combined in an injectable crosslinked hydrogel with controlled Gel-HA ratio. HA increases matrix stiffness. The addition of small amounts of HA leads to a signifi cant reduction in hydrogel shrinking after cell encapsulation (C2C12 myoblasts). We show that hydrogel stiffness counterbalanced traction forces of cells and this was decisive in promoting cell differentiation and myotube formation of C2C12 encapsulated in the hybrid hydrogels.
Gelatin–hyaluronic acid (Gel–HA) hybrid hydrogels have been proposed as matrices for tissue engineering because of their ability to mimic the architecture of the extracellular matrix. Our aim was to explore whether tyramine conjugates of Gel and HA, producing injectable hydrogels, are able to induce a particular phenotype of encapsulated human mesenchymal stem cells without the need for growth factors. While pure Gel allowed good cell adhesion without remarkable differentiation and pure HA triggered chondrogenic differentiation without cell spreading, the hybrids, especially those rich in HA, promoted chondrogenic differentiation as well as cell proliferation and adhesion. Secretion of chondrogenic markers such as aggrecan, SOX-9, collagen type II, and glycosaminoglycans was observed, whereas osteogenic, myogenic, and adipogenic markers (RUNX2, sarcomeric myosin, and lipoproteinlipase, respectively) were not present after 2 weeks in the growth medium. The most promising matrix for chondrogenesis seems to be a mixture containing 70% HA and 30% Gel as it is the material with the best mechanical properties from all compositions tested here, and at the same time, it provides an environment suitable for balanced cell adhesion and chondrogenic differentiation. Thus, it represents a system that has a high potential to be used as the injectable material for cartilage regeneration therapies.
Excessive water sorption and low mechanical properties are a severe drawback in some biomedical applications of hyaluronic acid (HA). A way to improve these properties is here explored through the novel concept of nanohybrid hydrogels consisting of a HA matrix including different amounts of silica-derived species. This inorganic filler phase controls the mechanical and swelling properties of HA cross-linked matrices. Below a 2 wt % of silica in the systems, nanoparticle aggregates of tens of nanometers and silica oligomers are distributed more or less homogeneously throughout the organic matrix, without percolating. This morphology of the silica phase is accompanied by an increased swelling degree of the composite when compared with pure HA. For higher silica mass ratios in the composites the inorganic counterpart coalesces, leading to a continuous inorganic silica network interpenetrated with the organic HA network, which coexists with a dispersed phase of silica-nanoparticle aggregates. Silica oligomers originating in the exposition of the nanoparticles to reactives during the composite preparation procedure contribute to the continuity of the silica network. For these compositions, swelling is reduced three times when compared with pure HA, and a significant improvement of the mechanical properties occurs. Water-containing samples of these materials exhibited a glass transition, which pure dry HA does not. None of the compositions studied showed any cytotoxicity. Thus, the materials could be of use in tissue engineering applications where these properties of HA need to be modulated.
While rail transport is growing for medium-distance journeys, the first and last miles are travelled by road, marking a change of transport mode in inland terminals (ITs). Moreover, the introduction of ITs in seaport hinterlands is increasing with a view to decongesting ports, and the best transport mode to connect these ITs with ports is that of rail.In 2013, chemicals were involved in 48 rail accidents in the EU-28 and in 667 in the United States (US). An appropriate design for the layout of inland terminals for containers with dangerous goods (ITDGs) involved in the rail system will increase the safety and operability of rail transport, avoiding accidents such as Tianjin (2015).The novelty of this work is a methodology to design the layout of ITDGs involved in rail transport through a hierarchy of container handling equipment (CHE), used in the yard of the terminal for a safer, more resilient and more environmentally friendly rail transport.The AHP (analytic hierarchy process) was used to hierarchize five alternative layouts, one for each CHE used in the yard; and according to criteria belonging to three areas: safety and security, environment and equipment performance. Results show that a layout linked to platforms is the preferred alternative for storing containers with dangerous goods (DGs) in ITs connected to railways.The implementation of this methodology will reduce consequences in the case of a serious accident in, or terrorist attack on, ITDGs involved in the rail system and GHG (greenhouse gas) emissions in the terminal. a key role in diminishing the pressure on the inland segment of freight distribution. This will reduce traffic, risk, and associated environmental impacts in regions surrounding ports and may become a relevant element of the supply chain. This is especially true due to the high costs for companies and legal requirements involved in seaport facilities. The mode of transport (road, barge or rail) used to access the hinterland from the seaport will depend on the distance between them, their availability, the costs and the quality of the service (e.g. transit times). The use of rail transport, from a cost perspective, is the most competitive in distant terminals (more than 300 km). However, rail has also been used for close (less than 100 km) and mid-range terminals to
Short poly-L-lactic acid (PLLA) microfibers have been produced in order to disperse them into the gelatin solution and enable injection in the tissue defect prior to gel formation. Two methods for fabrication of loose fibers with submicrometric dimensions are presented in this paper. One is based on manufacturing electrospun meshes and subsequent milling (PLLA-ES) and the other involves projection of a PLLA solution into a high turbulent non-solvent medium (PLLA-HT). Composites produced with PLLA-ES show a compression Young's modulus from 2.65 kPa for the pure gelatin to 6.69 kPa for the composite with 1.5% PLLA-ES fibers. The new injectable gelatin-fiber composites are not cytotoxic.
Maritime transport in the European Union has increased in the last years, triggering congestion in many of the most important sea and river ports. A lot of works have highlighted how the connection between these ports and dry ports can contribute to reducing port congestion and emission of greenhouse gases (GHGs). This work aims to improve the knowledge about the functionalities of Terminal Operating Systems (TOSs) managing container terminals of sea, river, and dry ports, with the aim of improving their performance and contributing to reducing congestion and GHG emissions to achieve a higher sustainability. The contribution and novelty of this paper in the field of container-terminals logistics research is the use of the Analytic Hierarchy Process (AHP) to identify and hierarchize TOS functionalities. The robustness of the model was checked by applying a sensitivity analysis. One hundred and seven functionalities were grouped into six main clusters: Warehouse, Maritime Operations, Gate, Master Data, Communications, and ERP (Enterprise Resource Planning) Dashboard. The results show that time tracking of vessels, space optimization, development of loading and unloading lists, and optimization of container locations are the most important functionalities of a TOS. This work is addressed to developers, sellers, managers, and users of TOSs and researchers working on container-terminal performance.
The increased number of transports with dangerous goods (TDG) increases the risk of both accidents and terrorist attacks. Digitalisation is crucial in order to avoid human errors and to increase safety, security and efficiency, however there are few research studies that analyse digitalisation for the TDG, this being the first time, to the author's knowledge, that barriers to the implementation of information and communication technology (ICT) solutions for the transport of dangerous goods has been analysed. A new elicitation methodology called the 'implementation acceleration methodology for ICT (IAM-ICT)' has been created, with the aim of identifying and hierarchizing potential barriers to the implementation and integration of ICT solutions involved in the multimodal TDG, and with a view to overcoming the most relevant problems at an early stage. This methodology combines user-driven innovation (UDI), the analytic hierarchy process (AHP) and Bayesian networks. The application of this methodology, which is easily replicable in other fields, will enable a better design of ICT solutions so that they can be implemented and integrated in SMEs and large companies. The results show a hierarchy of potential barriers for a multi-modular ICT solution used as use case study, in two different co-designed schemes for a small and medium enterprise (SME) and for a large company.
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