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This paper reviews structural health monitoring (SHM) techniques of bridge structures based on machine learning (ML) algorithms. Regular inspections and the use of non-destructive testing are still the common damage-detection methods; however, they are susceptible to subjectivity and human error and involve prolonged duration. With emerging technologies such as artificial intelligence and the development of wireless sensors, SHM has shifted from offline model-driven damage detection to online/real-time data-driven damage detection. In this paper, both supervised and unsupervised ML algorithms are examined to determine which of the latest methods would be the most suitable and effective for the SHM of bridge structures. This review paper investigates recent studies on data acquisition, data imputation, data compression, feature extraction and pattern recognition using supervised/unsupervised ML algorithms. [ABSTRACT FROM AUTHOR]

Damage detection in bridge structures plays a crucial role in the 'in-time' maintenance of such structures, which subsequently prevents further propagation of the damage, and likely collapse of the structure. Currently, the applications of machine learning algorithms are growing in the smart damage detection of structures. This work focuses on application of a new machine learning algorithm to identify the location and severity of damage in truss bridges. Frequency response functions are used as damage features, and are compressed using principal component analysis. Couple sparse coding is adopted as a classification method to learn the relationship between the bridge damage features and its damage states. Two truss bridges are used to test the proposed method and determine its accuracy in the detection of damage to truss bridges. It is found that the proposed method provides a reliable detection of damage location and severity in truss bridges. [ABSTRACT FROM AUTHOR]

A large proportion of Iranian railway bridge assets comprises masonry arch bridges, which have been in service for over 70 years. Seismic assessment of such structures is very important, particularly for highly seismic regions. This study assesses the seismic performance of Veresk masonry arch bridge, the longest masonry arch bridge in the Iranian railway network (span length 99 m), spanning a valley 110 m deep, through reliable sensor-based model updating. Dynamic tests are conducted using a test train, composed of six-axle locomotives and four-axle freight wagons, which travels across the bridge; the vibration response of the instrumented bridge is subsequently measured. A high-fidelity three-dimensional finite-element model of the bridge is developed and updated using the measured vibration characteristics: mid-span displacements and natural frequencies. Finally, a seismic performance assessment of the bridge is performed using non-linear static and dynamic analyses for two seismic hazard levels with return periods of 150 and 1000 years. It is found that, for the hazard level with a return period of 150 years, both non-linear static and dynamic analyses give very similar results. However, for the seismic hazard level with a return period of 1000 years, the results of the static analysis are more conservative. [ABSTRACT FROM AUTHOR]

Currently, CAR-T cell therapy is known as an efficacious treatment for patients with relapsed/refractory hematologic malignancies. Nonetheless, this method faces several bottlenecks, including low efficacy for solid tumors, lethal adverse effects, high cost of autologous products, and the risk of GvHD in allogeneic settings. As a potential alternative, CAR-NK cell therapy can overcome most of the limitations of CAR-T cell therapy and provide an off-the-shelf, safer, and more affordable product. Although published results from preclinical and clinical studies with CAR-NK cells are promising, several bottlenecks must be unlocked to maximize the effectiveness of CAR-NK cell therapy. These bottlenecks include low in vivo persistence, low trafficking into tumor sites, modest efficacy in solid tumors, and sensitivity to immunosuppressive tumor microenvironment. In recent years, advances in gene manipulation tools and strategies have laid the groundwork to overcome the current bottlenecks of CAR-NK cell therapy. This review will introduce the existing gene manipulation tools and discuss their advantages and disadvantages. We will also explore how these tools can enhance CAR-NK cell therapy's safety and efficacy. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are a group of toxic chemicals formed during incomplete combustion of organic materials. In this study, the 16 PAHs were investigated in meat and meat products. Literature search was performed in Scopus, PubMed and Web of Science databases from 2000 to 2021. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was used. Fifteen (15) studies containing 155 observations were selected based on the criteria. The sum of 16 PAHs ranged from 0.4 to 2290.32 µg/kg (wet weight). Low-weight PAH were dominant species. The pooled weight of the studies indicated that the effect size of PAH concentration was 4.02 µg/kg (95% CI = 0.495 to 7.545, p = 0.03) with the I2, Q statistics and Tau2 corresponding to 47.61, 638.36 values and 100%, respectively. The upper confidence limit (UCL) for excess lifetime cancer risk (ELCR) estimates ranged from 2.76 × 10−5 to 1.15 and in 97% of estimates, the ELCR value showed high potential risk. The UCL for the hazard index (HI) estimates ranged from 2.53 × 10−3 to 33.9 from which 39.35% of the estimates displayed high non-carcinogenic health risks. Environmental contamination in raw samples and cooking procedures in processed samples were responsible for further PAH formation. [ABSTRACT FROM AUTHOR]

Over the last decade, economic and environmental factors have led to low salinity water injection (LSWI) becoming one of the most important improved oil recovery methods. Although many results have been obtained from laboratory tests, only a few papers have been published regarding the modeling and simulating LSWI in carbonate reservoirs compared to sandstone reservoirs. This paper investigated the most affecting parameters on oil recovery during LSWI at the core and field scale. The published work focused more on the effective parameters related to ultimate oil recovery using LSWI. However, important parameters affecting the oil recovery rate were not investigated. We compared how important parameters affected the ultimate oil recovery factor and ultimate oil recovery rate. According to the results of this study, the salinity of injected water and curvature of oil relative permeability were the most important factors on the ultimate oil recovery factor. By reducing both of these parameters, more increment oil was recovered. By increasing the injection rate of water, the curvature of the water relative permeability, wettability, and the endpoint of oil relative permeability, the oil recovery rate also increased. Furthermore, threshold capillary pressure and the endpoint of relative permeability of water had inverse effects on oil recovery. Injecting low salinity water into the reservoir will change its wettability. As a result, it will change the properties of the reservoir and increase the production from the reservoir, resulting in more oil being produced. LSWI resulted in an increase of oil recovery factor of 5% and 11% respectively after 25 and 58 years in this case. [ABSTRACT FROM AUTHOR]

In recent years, accelerated bridge construction has led to the substantial application of precast post-tensioned segmental (PPS) bridge piers. However, PPS piers are not widely used in high-seismicity regions due to their low energy-dissipation capacity (EDC). To address this deficiency, a series of shape memory alloy (SMA)–concrete composite PPS piers were examined in this work. Non-linear static and dynamic analyses were performed on experimentally validated finite-element models of the SMA–concrete composite piers and the results were compared with those of piers without SMA bars. It was found that the length, area and post-tensioning ratio of the SMA bars affected the EDC of the piers, and an optimal design of the bars is required to reach the highest EDC possible. The effects of SMA bars on the frequency response functions of piers were investigated for the first time in this study and it was found that, unlike the piers without SMA bars, sub-harmonics and super-harmonics were not seen in the responses of the SMA–concrete composite piers, mainly the drift responses. Furthermore, the SMA–concrete composite piers experienced a significant reduction in drift responses compared with piers without SMA bars. [ABSTRACT FROM AUTHOR]