Initial crack detection in concrete plate and shell structures using concept of earthquake ground motions

Many methods and sensors have been developed for crack detection in concrete structures and for earthquake ground motion detection, respectively. In a previous study, a seismo-accelerometer based on spring-mass strong motion seismo-accelerograph has been developed for the purpose of detecting earthquake waves travelling through the earth crust from the epicenter at faultline. This study aims to apply the method developed in previous study to detect wave from crack initiation point on the surface of plate and shell concrete as a new alternative for initial crack detection method. This study focused on the development of a downscaled seismo-accelerometer of previous study for better ease of use. Concrete plate and shell specimens were selected in this study as the travel of wave from crack initiation point in the specimen mimic to that of earthquake waves travelling through the earth crust from the epicenter at the faultline. Magnetometer technology and spring-mass system formed the fundamental design aspect of the seismo-accelerometer. In Objective 1, the seismo-accelerometer was designed using Finite Element Modelling to attain natural period of 1 second, required for spring-mass based strong motion accelerograph. The modelling yield natural period of 0.99475 second and verified experimentally with Harmonic Shake Table test yielding 1.2 seconds, which is in the acceptable range. Ground motion test was carried out at Ranau Meteorological Station and the results were compared with international earthquake database. Earthquakes detected are in Sabah and nearby regions. Crack induction tests on factory-ready concrete plate and shell specimens were carried out in Objective 2, where the results shown that the concept of ground motion detection can be used for crack detection purposes. The crack detection equations for factory-ready concrete plate and shell are Mcrack,plate = log10A + 0.6919 and Mcrack,shell = log10A + 0.7115, respectively. Objective 3 provides the proof that the ground motion detection can be applied for crack detection based on crack wave attenuation on structures such as concrete plate and shell which have the same configuration as earth crust, where the earthquakes occur. Thus, the seismo-accelerometer developed in the study can be used for earthquake ground motion detection if placed on the bedrock or ground, and can be used for crack detection if placed on structures with similar configuration to earth crust such as concrete plate and shell structures. This contributes towards both Structural Health Monitoring and Seismic Monitoring apart from providing an alternative method to existing methods in both fields

One-way transnational magnetic mass damper model for structural response control against dynamic loadings

Structural responses should be reduced to minimize the consequent structural damage caused by dynamic excitation. The one-way translational magnetic mass damper model is developed as a new type of damper for the purpose of structural response control. The damper utilizes the concept of repulsive force between magnets with same poles to create a magnetic force to stabilize or bring the structure back to its original position. The dynamic performance of the structure was tested using a harmonic shaking table. In this study, the three parameters used are excitation speeds: 2.5V (low), 6.0V (medium) and 8.5V (high); strength of magnets: weak (N35), medium (N45) and strong (N52); and the mass in the damper: 40 g, 101 g and 162 g. The correlations of the parameters towards the structural displacement are verified in the testing. The displacement is highly reduced up to 100% at the first level and 85.2% at the fifth level. The most optimum structural response control was attained when a strong magnetic strength and mass of 162 g are used. When tested with three excitation speeds; 2.5V, 6.0V and 8.5V, the damper with this setting provides the optimum damping effect towards the structure in terms of displacement

Shear capacity evaluation of reinforced concrete beams: finite element simulation

The shear performance of reinforced concrete beams with rectangle cross-section and two different continuous rectangular spiral shear reinforcement under monotonous loading is numerically evaluated. Further, the behaviour of two continuous shear reinforcement systems named, “Single Square Spring Shear Resistance System” (SSSSRS) and “Double Square Spring Shear Resistance System” (DSSSRS) as transverse reinforcements are compared with conventional discontinuous system “Stirrups”. The finite element study includes three (3) beams. The results clearly show that the application of continuous shear reinforcement system delivered improved shear behaviour and enhanced bearing capacity in beams. Beams with Single Square Spring Shear Resistance System (SSSSRS) and Double Square Spring Shear Resistance System (DSSSRS) exhibited 14.4% and 19.8% increased shear performance in comparison with conventional control beam. It was concluded that under the same deflection higher forces was achieved for “Single Square Spring Shear Resistance System” (SSSSRS) and “Double Square Spring Shear Resistance System” (DSSSRS) compared to control specimens

Skeletal Muscle Phenotypically Converts and Selectively Inhibits Metastatic Cells in Mice

Skeletal muscle is rarely a site of malignant metastasis; the molecular and cellular basis for this rarity is not understood. We report that myogenic cells exert pronounced effects upon co-culture with metastatic melanoma (B16-F10) or carcinoma (LLC1) cells including conversion to the myogenic lineage in vitro and in vivo, as well as inhibition of melanin production in melanoma cells coupled with cytotoxic and cytostatic effects. No effect is seen with non-tumorigenic cells. Tumor suppression assays reveal that the muscle-mediated tumor suppressor effects do not generate resistant clones but function through the down-regulation of the transcription factor MiTF, a master regulator of melanocyte development and a melanoma oncogene. Our findings point to skeletal muscle as a source of therapeutic agents in the treatment of metastatic cancers

Neutrophil Extracellular Traps in Breast Cancer and Beyond: Current Perspectives on NET Stimuli, Thrombosis and Metastasis, and Clinical Utility for Diagnosis and Treatment

Abstract The formation of neutrophil extracellular traps (NETs), known as NETosis, was first observed as a novel immune response to bacterial infection, but has since been found to occur abnormally in a variety of other inflammatory disease states including cancer. Breast cancer is the most commonly diagnosed malignancy in women. In breast cancer, NETosis has been linked to increased disease progression, metastasis, and complications such as venous thromboembolism. NET-targeted therapies have shown success in preclinical cancer models and may prove valuable clinical targets in slowing or halting tumor progression in breast cancer patients. We will briefly outline the mechanisms by which NETs may form in the tumor microenvironment and circulation, including the crosstalk between neutrophils, tumor cells, endothelial cells, and platelets as well as the role of cancer-associated extracellular vesicles in modulating neutrophil behavior and NET extrusion. The prognostic implications of cancer-associated NETosis will be explored in addition to development of novel therapeutics aimed at targeting NET interactions to improve outcomes in patients with breast cancer

Role of DNA methylation in head and neck cancer

Head and neck cancer (HNC) is a heterogenous and complex entity including diverse anatomical sites and a variety of tumor types displaying unique characteristics and different etilogies. Both environmental and genetic factors play a role in the development of the disease, but the underlying mechanism is still far from clear. Previous studies suggest that alterations in the genes acting in cellular signal pathways may contribute to head and neck carcinogenesis. In cancer, DNA methylation patterns display specific aberrations even in the early and precancerous stages and may confer susceptibility to further genetic or epigenetic changes. Silencing of the genes by hypermethylation or induction of oncogenes by promoter hypomethylation are frequent mechanisms in different types of cancer and achieve increasing diagnostic and therapeutic importance since the changes are reversible. Therefore, methylation analysis may provide promising clinical applications, including the development of new biomarkers and prediction of the therapeutic response or prognosis. In this review, we aimed to analyze the available information indicating a role for the epigenetic changes in HNC

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030