Adipose-derived stem cells (ASCs) are a mesenchymal stem cell source with properties of self-renewal and multipotential differentiation. Compared to bone marrow-derived stem cells (BMSCs), ASCs can be derived from more sources and are harvested more easily. Three-dimensional (3D) tissue engineering scaffolds are better able to mimic the in vivo cellular microenvironment, which benefits the localization, attachment, proliferation, and differentiation of ASCs. Therefore, tissue-engineered ASCs are recognized as an attractive substitute for tissue and organ transplantation. In this paper, we review the characteristics of ASCs, as well as the biomaterials and tissue engineering methods used to proliferate and differentiate ASCs in a 3D environment. Clinical applications of tissue-engineered ASCs are also discussed to reveal the potential and feasibility of using tissue-engineered ASCs in regenerative medicine.

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Adipose-Derived Stem Cells for Tissue Engineering and Regenerative Medicine Applications

Fiber-reinforced polymer (FRP) composites are extensively used in advanced concrete technology given their superiority over traditional steel reinforcements. These materials possess high strength capacity and corrosion resistance and can be employed as the main reinforcements in combination with adhesives and anchorages to strengthen reinforced concrete (RC) beam members. RC beams are designed to provide resistance against flexure , shear, torsion, fatigue, impact, and blast loading. The strength and ductility of RC beams can be improved via FRP strengthening techniques with a combination of fibers. The overall strength of FRP composites in RC beams is controlled by fiber type , configuration, and materials and strengthening technique. This review focuses on the characteristics and behaviors of FRP-strengthened RC beams under various loading conditions. It also presents the typical FRP composites with the properties, features, and applications. This review demonstrates that FRP composites can be used to recover the strength of damaged and corroded beams and exhibit good durability and insulation performance. It also provides a straightforward perspective of strengthening and retrofitting techniques for RC beams using FRP composites.

Strengthening of reinforced concrete beams by using fiber-reinforced polymer composites: A review

Properties and applications of FRP in strengthening RC structures: A review

This paper presents experimental research on reinforced concrete (RC) beams with external flexural and flexural–shear strengthening by fibre reinforced polymer (FRP) sheets consisting of carbon FRP (CFRP) and glass FRP (GFRP). The work carried out has examined both the flexural and flexural–shear strengthening capacities of retrofitted RC beams and has indicated how different strengthening arrangements of CFRP and GFRP sheets affect behaviour of the RC beams strengthened. Research output shows that the flexural–shear strengthening arrangement is much more effective than the flexural one in enhancing the stiffness, the ultimate strength and hardening behaviour of the RC beam. In addition theoretical calculations are developed to estimate the bending and shear capacities of the beams tested, which are compared with the corresponding experimental results.

Structural behaviour of RC beams with external flexural and flexural-shear strengthening by FRP sheets

Flexural response of reinforced concrete (RC) beams strengthened with near surface mounted (NSM) fibre reinforced polymer (FRP) bars

Near surface mounted (NSM) and externally bonded reinforcement (EBR) strengthening techniques are based on the use of carbon fiber reinforced polymer (CFRP) materials and have been used for the structural rehabilitation of concrete structures. In the present work, the efficacies of the NSM and EBR techniques for the flexural and shear strengthening of reinforced concrete beams are compared carrying out two experimental groups of tests. For the flexural strengthening, the efficacy of applying CFRP laminates according to NSM is compared to those resulting from applying CFRP laminates and wet lay-up CFRP sheets according to EBR technique. The influences of the equivalent reinforcement ratio (steel and laminates) and spacing of the laminates on the efficiency of the NSM technique for the flexural strengthening is also investigated. A numerical strategy is implemented to analyze the applicability of the FRP effective strain concept, proposed by ACI and fib in the design of FRP systems for the flexural strengthening. To assess the efficacy of the NSM technique for the shear strengthening of concrete beams, four beam series of distinct depth and longitudinal tensile steel reinforcement ratio are tested. Each series is composed of one beam without any shear reinforcement and one beam using the following shear reinforcing systems: conventional steel stirrups; strips of wet lay-up CFRP sheet of U configuration applied according to EBR technique; and laminates of CFRP embedded into vertical or inclined (45°) pre-cut slits on the concrete cover of the beam lateral faces, according to the NSM technique. Using the obtained experimental results, the performance of the analytical formulations proposed by ACI, fib and Italian guidelines is appraised.

Efficacy of CFRP-based techniques for the flexural and shear strengthening of concrete beams

In this paper the trustworthiness of the existing theory for predicting the fiber-reinforced plastic contribution to the shear resistance of reinforced concrete beams is discussed. The most well-known shear models for external bonded reinforcement are presented, commented on, and compared with an extensive experimental database. The database contains the results from more than 200 tests performed in different research institutions across the world. The results of the comparison are not very promising and the use of the additional principle in the actual shear design equations should be questioned. The large scatter between the predicted values of different models and experimental results is of real concern bearing in mind that some of the models are used in present design codes.

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Are Available Models Reliable for Predicting the FRP Contribution to the Shear Resistance of RC Beams

This work presents a statistically oriented study aiming to assess the reliability of some of the most well-known design models available for the prediction of the contribution of fibre-reinforced polymer (FRP) systems applied according to the externally bonded reinforcing (EBR) technique for the shear strengthening of reinforced concrete (RC) beams. Relevant data were collected from experimental programmes carried out in recent years in the context of shear strengthening with FRP, and an extended database was obtained. Using these data, the performance of different design guidelines was appraised by means of comparing the contribution of the FRP shear systems predicted by analytical formulations with those registered experimentally. In general, the obtained results were not very promising, since a large scatter of the design safety factor was observed and, for some cases, the contribution of the FRP systems predicted by the design models was highly unconservative. This may be of serious concern as these ...

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Reliability analysis of shear strengthening externally bonded FRP models

https://repositorium.sdum.uminho.pt/bitstream/1822/37013/1/18467-The%20effect%20of%20magnetic%20stimulation%20on%20the%20osteogenic%20and%20chondrogenic.pdf

The effect of magnetic stimulation on the osteogenic and chondrogenic differentiation of human stem cells derived from the adipose tissue (hASCs)

Experimental studies conducted worldwide on reinforced concrete (RC) beams strengthened in shear with externally bonded (EBR) fiber-reinforced polymers (FRP) over the last years evince the reliability and efficacy of such technique for structural retrofitting. For elements with shear resistance deficiencies, an higher load carrying capacity may be achieved by bonding FRP reinforcement systems with the fibers as orthogonal as practically possible to the critical shear crack plane for an optimal configuration, or with the fibers normal to the beam axis for a more practical setting. Common configurations of strengthening (Fig.1) include the full wrapping of the cross section (O), U jacketing along 3 sides (U) and side bonding in the beam web (S). Additional mechanical anchorage systems can be provided to enhance the behavior of U or S configurations where the available bond length is short (U+ and S+).

https://repositorium.sdum.uminho.pt/bitstream/1822/13154/1/IC_60.pdf

João L. T. Lima

Papers

Efficacy of CFRP-based techniques for the flexural and shear strengthening of concrete beams

Are Available Models Reliable for Predicting the FRP Contribution to the Shear Resistance of RC Beams

Reliability analysis of shear strengthening externally bonded FRP models

The effect of magnetic stimulation on the osteogenic and chondrogenic differentiation of human stem cells derived from the adipose tissue (hASCs)

Design models for shear strengthening of reinforced concrete beams with externally bonded FRP composites : a statistical vs reliability approach