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Seismic fragility analysis of deteriorated bridge structures employing a UAV inspection-based updated digital twin
No full textAging bridges require regular inspection due to performance deterioration. For this purpose, numerous researchers have considered the use of unmanned aerial vehicle (UAV) systems for structural health monitoring and inspection. However, present UAV-based inspection methods only represent the type and extent of external damage, but does not assess the seismic performance. In this study, a seismic fragility analysis of deteriorated bridges employing a UAV inspection-based updated digital twin is proposed. The proposed method consists of two phases: (1) bridge condition assessment using UAV inspection for updating the digital twin and (2) seismic fragility analysis based on the updated digital twin. To update the digital twin, the bridge damage grade is assigned based on the UAV inspection, and subsequently, the corresponding damage index is calculated. The damage index is utilized as a percentage reduction in the stiffness of finite element (FE) model, based on a previously proposed research. Using the updated digital twin, the seismic fragility analysis is conducted with different earthquake motions and magnitudes. To demonstrate the proposed method, an inservice pre-stressed concrete box bridge is examined. In particular, the seismic fragility curves of deteriorated bridges are compared with those of intact bridges. The numerical results show that the maximum failure probability of the deteriorated bridges is 3.6% higher than that of intact bridges. Therefore, the proposed method has the potential to updated the digital twin effectively using UAV inspection, allowing for seismic fragility analysis of deteriorated bridges to be conducted
Comparison of the immune activation capacities of fucoidan and laminarin extracted from Laminaria japonica
No full textLaminaria japonica is a brown alga and is composed primarily of polysaccharides. Fucoidan and laminarin are the major polysaccharides of L. japonica and exhibit biological activities, including immune modulation and anti-coagulant and antioxidant effects in animals and humans. In this study, we evaluated the ability of fucoidan and laminarin from L. japonica to induce immune cell activation and anti-cancer immunity, which has not yet been studied. The injection of fucoidan to mice promoted the upregulation of major histocompatibility complex and surface activation molecules in splenic dendritic cell subsets, whereas laminarin showed a weaker immune activation ability. In addition, fucoidan treatment elicited inflammatory cytokine production; however, laminarin did not induce the production of these cytokines. Regarding cytotoxic cell activities, fucoidan induced the activation of lymphocytes, including natural killer and T cells, whereas laminarin did not induce cell activation. Finally, fucoidan enhanced the anticancer efficacy of anti-programmed Death-Ligand 1 (PD-L1) antibody against Lewis lung carcinoma, whereas laminarin did not promote the cancer inhibition effect of anti-PD-L1 antibody. Thus, these data suggest that fucoidan from L. japonica can be used as an immune stimulatory molecule to enhance the anticancer activities of immune checkpoint inhibitors
High-yield production of mono- or few-layer transition metal dichalcogenide nanosheets by an electrochemical lithium ion intercalation-based exfoliation method
No full textTransition metal dichalcogenide (TMD) nanomaterials, especially the mono- or few-layer ones, have received extensive research interest owing to their versatile properties, ranging from true metals (e.g., NbS2 and VSe2) and semimetals (e.g., WTe2 and TiSe2) to semiconductors (e.g., MoS2 and We(2)) and insulators (e.g., HfS2). Therefore, the reliable production of these nanomaterials with atomically thin thickness and laterally uniform dimension is essential for their promising applications in transistors, photodetectors, electroluminescent devices, catalysis, energy conversion, environment remediation, biosensing, bioimaging, and so on. Recently, the electrochemical lithium ion intercalation-based exfoliation method has emerged as a mature, efficient and promising strategy for the high-yield production of mono- or few-layer TMD nanosheets; monolayer MoS2 (yield of 92%), monolayer TaS2 (yield of 93%) and bilayer TiS2 (yield of 93%) with lateral dimensions of similar to 1 mu m (refs. (1-3)). This Protocol describes the details of experimental procedures for the high-yield synthesis of mono- or few-layer TMDs and other inorganic nanosheets such as MoS2, WS2, TiS2, TaS2, ZrS2, graphene, h-BN, NbSe2, WSe2, Sb2Se3 and Bi2Te3 by using the electrochemical lithium ion intercalation-based exfoliation method, which involves the electrochemical intercalation of lithium ions into layered inorganic crystals and a mild sonication process. The whole protocol takes 26-38 h for the successful production of ultrathin inorganic nanosheets
Fabrication of Graphene-Incorporated Thermoresponsive Nanocomposite Hydrogels with Precision Control of Programmable Actuation
No full textHydrogels capable of stimuli-responsive deformation are widely explored as intelligent actuators for diverse applications. It is still a significant challenge, however, to ???program??? these hydrogels to undergo highly specific and extensive shape changes with precision, because the mechanical properties and deformation mechanism of the hydrogels are inherently coupled. Herein, two engineering strategies are simultaneously employed to develop thermoresponsive poly(N-isopropyl acrylamide) (PNIPAm)-based hydrogels capable of programmable actuation. First, PNIPAm is copolymerized with poly(ethylene glycol) diacrylate (PEGDA) with varying molecular weights and concentrations. In addition, graphene oxide (GO) or reduced graphene oxide (rGO) is incorporated to generate nanocomposite hydrogels. These strategies combine to allow the refined control of mechanical and diffusional properties of hydrogels over a broad range, which also directly influences variable thermoresponsive actuation. It is expected that this comprehensive design principle can be applied to a wide range of hydrogels for programmable actuation
Anisotropic Nanofiber-Laden Hydrogel as Guidance to 3D Cell Orientation
No full textAlong with continuous research in biotechnology, there is a growing demand for cell culture platforms that can provide a more biological microenvironment to induce complex cell behavior. The extracellular matrix (ECM) controls chemical signals and stores cytokines and nutrients beyond the structural support of tissue. It also serves to control the physical signals mediated by the integrins and has structural diversity. On the other hand, in conventional plastic substrates such as flasks and well plates, cells are attached to the surface and cultured so the behavior of cells can be explored only by the response to chemical signals such as growth factors. To mimic various biological tissues, an extracellular matrix environment suitable for each cell activity must be served.
The three-dimensional hydrogel culture system can control mechanical properties within a physiological range by controlling crosslinking density of polymer. Hydrogel can also provide a microenvironment that mimics natural surroundings for cell growth. However, overall hydrogel structures were difficult to control the fine physical properties of the cell niche. The limitation of controlling the local environment around cells can be studied by introducing other nanomaterials within hydrogels.
Electrospun nanofibers are widely used as scaffolds in tissue engineering that they are easy to fabricate and can simulate the structure of natural proteins derived from ECM. The other advantage of introducing nanofibers is that the porosity of the hydrogel can be maintained and the stiffness of the local area is controlled by the fiber density. Moreover, nanofibers can recreate the topographical heterogeneity of ECM architectures.
In particular, aligned structures of connective tissue can be easily found across soft tissue, skeletal muscle, heart tissue, and cancer tumor. From a microscopic point of view, the aligned structure affects angiogenesis, ECM reconstruction, and, electrical signal propagation in neurons. From a macroscopic point of view, it supports tendon loading, transmits muscle force, and is used to determine the malignant prognosis of tumors.
However, the traditional strategy to control the direction of cell migration is to give a chemical or physical cell adhesion gradient that would change cellular fates. Moreover, mimicking anisotropy in a three-dimensional structure still has been a challenge.
Hence, this research demonstrates to regulate the orientation of cells along gelatin nanofibers aligned under an external magnetic field. This work establishes a new multifunctional scaffold strategy that mimics the aligned three-dimensional fiber structure of various nature tissues with independent control of physical and chemical properties
Asymmetric Magnetization Reversal of the Soft layer in the Pt/Co bilayer with Perpendicular magnetic anisotropy
No full textStructured hollow fiber ultrafiltration membrane for antifouling mitigation
No full textTailoring of membranes for application in various field could be the key to lessen the burden from the critical water shortage situation worldwide. Ultrafiltration membranes (with effective pore size in the range of 0.001 to 0.05??m) drew much attention owning to its cost-effective (Yu, Liu, 2018) and universal applicability. Herein, the fabrication of Polyethersulfone (PES) structured hollow fiber ultrafiltration membrane via the reversed thermally induced phase separation technique and a designed spinneret are proposed. The aims of this research are: 1) to prepare self-supporting membrane with optimized bi-continuous structure from the novel membrane preparation technique (Kahrs, G??hlstorf, 2019) and 2) to mitigate fouling tendency which is the biggest hindrance to the wider application of membrane technology with local turbulences from its structured surface (Culfaz, Wessling, 2011). The fabricated membranes showed bi-continuous cross-sectional structure, micro patterns on the outer surface and less flux decline compared to the commercial membrane in a general protein fouling test
