A Numerical Approach for Calculation of Characteristics of Edge Waves in Three-Dimensional Plates

© 2020 World Scientific Publishing CompanySurface waves have been extensively studied in earthquake seismology. Surface waves are trapped near an infinitely large surface. The displacements decay exponentially with depth. These waves are also named Rayleigh and Love waves. Surface waves are also used for nondestructive testing of surface defects. Similar waves exist in finite width three-dimensional plates. In this case, displacements are no longer constant in the direction perpendicular to the wave propagation plane. Wave energy could still be trapped near the edge of the three-dimensional plate, and hence the term edge waves. These waves are thus different to the two-dimensional Rayleigh and Love waves. This paper presents a numerical model to study dispersion properties of edge waves in plates. A two-dimensional semi-analytical finite element method is developed, and the problem is closed by a perfectly matched layer adjacent to the edge. The numerical model is validated by comparing with available analytical and numerical solutions in the literature. On this basis, higher order edge waves and mode shapes are presented for a three-dimensional plate. The characteristics of the presented edge wave modes could be used in nondestructive testing applications.Peer reviewe

The implications of an incidental chronic lymphocytic leukaemia in a resection specimen for colorectal adenocarcinoma

<p>Abstract</p> <p>Background</p> <p>Colorectal cancer and B cell chronic lymphocytic leukaemia (CLL) have a significant incidence, which are increasing with the aging population. Evidence has been presented in the literature to suggest that the synchronous presentation of colorectal cancer and B cell CLL may be more than simply coincidental for these two common malignancies. We report an unusual case of a presumed B cell CLL diagnosed on the basis of histological analysis of lymph nodes recovered from a resection specimen for rectal adenocarcinoma. We considered aetiological factors which may have linked the synchronous diagnosis of the two malignancies and the potential implications for the natural history of the two malignancies on one another.</p> <p>Case presentation</p> <p>A 70-year-old male underwent low anterior resection with total mesorectal excision for a rectal adenocarcinoma. His co-morbid conditions were chronic obstructive airways disease and ischaemic heart disease. General examination revealed no lymphadenopathy. Full blood count, urea and electrolytes and liver function tests were all within normal limits. As well as confirming a pT3 N1 adenocarcinoma, histological analysis showed lymph nodes with an infiltrate of small lymphoid cells. Immunohistochemical studies showed these cells to be in keeping with B cell CLL.</p> <p>Conclusion</p> <p>Whilst unable to identify any common aetiological factors in the two malignancies in our patient, immunosuppression and genetic abnormalities have been identified as possible bases for an observed epidemiological association between colorectal cancer and haematological malignancies. Examples such as our case of synchronous diagnosis of two malignancies in a patient are likely to increase with the aging population. The potential affects of one malignancy on the natural history of the other warrants further study. In our case, we considered that slow progression of the B cell CLL may increase the risk of recurrent rectal adenocarcinoma.</p

Establishment of the milk-borne transmission as a key factor for the peculiar endemicity of human T-lymphotropic virus type 1 (HTLV-1): the ATL Prevention Program Nagasaki

In late 2010, the nation-wide screening of pregnant women for human T-lymphotropic virus type 1 (HTLV-1) infection was implemented in Japan to prevent milk-borne transmission of HTLV-1. In the late 1970s, recognition of the adult T-cell leukemia (ATL) cluster in Kyushu, Japan, led to the discovery of the first human retrovirus, HTLV-1. In 1980, we started to investigate mother-to-child transmission (MTCT) for explaining the peculiar endemicity of HTLV-1. Retrospective and prospective epidemiological data revealed the MTCT rate at ∼20%. Cell-mediated transmission of HTLV-1 without prenatal infection suggested a possibility of milk-borne transmission. Common marmosets were successfully infected by oral inoculation of HTLV-1 harboring cells. A prefecture-wide intervention study to refrain from breast-feeding by carrier mothers, the ATL Prevention Program Nagasaki, was commenced in July 1987. It revealed a marked reduction of HTLV-1 MTCT by complete bottle-feeding from 20.3% to 2.5%, and a significantly higher risk of short-term breast-feeding (<6 months) than bottle-feeding (7.4% vs. 2.5%, P < 0.001)

Tissue factor deficiency increases alveolar hemorrhage and death in influenza A virus-infected mice

Essentials H1N1 Influenza A virus (IAV) infection is a hemostatic challenge for the lung. Tissue factor (TF) on lung epithelial cells maintains lung hemostasis after IAV infection. Reduced TF-dependent activation of coagulation leads to alveolar hemorrhage. Anticoagulation might increase the risk for hemorrhages into the lung during severe IAV infection. Summary: Background Influenza A virus (IAV) infection is a common respiratory tract infection that causes considerable morbidity and mortality worldwide. Objective To investigate the effect of genetic deficiency of tissue factor (TF) in a mouse model of IAV infection. Methods Wild-type mice, low-TF (LTF) mice and mice with the TF gene deleted in different cell types were infected with a mouse-adapted A/Puerto Rico/8/34 H1N1 strain of IAV. TF expression was measured in the lungs, and bronchoalveolar lavage fluid (BALF) was collected to measure extracellular vesicle TF, activation of coagulation, alveolar hemorrhage, and inflammation. Results IAV infection of wild-type mice increased lung TF expression, activation of coagulation and inflammation in BALF, but also led to alveolar hemorrhage. LTF mice and mice with selective deficiency of TF in lung epithelial cells had low basal levels of TF and failed to increase TF expression after infection; these two strains of mice had more alveolar hemorrhage and death than controls. In contrast, deletion of TF in either myeloid cells or endothelial cells and hematopoietic cells did not increase alveolar hemorrhage or death after IAV infection. These results indicate that TF expression in the lung, particularly in epithelial cells, is required to maintain alveolar hemostasis after IAV infection. Conclusion Our study indicates that TF-dependent activation of coagulation is required to limit alveolar hemorrhage and death after IAV infection

The evolution of sex-specific virulence in infectious diseases

Fatality rates of infectious diseases are often higher in men than women. Although this difference is often attributed to a stronger immune response in women, we show that differences in the transmission routes that the sexes provide can result in evolution favouring pathogens with sex-specific virulence. Because women can transmit pathogens during pregnancy, birth or breast-feeding, pathogens adapt, evolving lower virulence in women. This can resolve the long-standing puzzle on progression from Human T-cell Lymphotropic Virus Type 1 (HTLV-1) infection to lethal Adult T-cell Leukaemia (ATL); a progression that is more likely in Japanese men than women, while it is equally likely in Caribbean women and men. We argue that breastfeeding, being more prolonged in Japan than in the Caribbean, may have driven the difference in virulence between the two populations. Our finding signifies the importance of investigating the differences in genetic expression profile of pathogens in males and females

Approximation for Cooperative Interactions of a Spatially-Detailed Cardiac Sarcomere Model

We developed a novel ordinary differential equation (ODE) model, which produced results that correlated well with the Monte Carlo (MC) simulation when applied to a spatially-detailed model of the cardiac sarcomere. Configuration of the novel ODE model was based on the Ising model of myofilaments, with the “co-operative activation” effect introduced to incorporate nearest-neighbor interactions. First, a set of parameters was estimated using arbitrary Ca transient data to reproduce the combinational probability for the states of three consecutive regulatory units, using single unit probabilities for central and neighboring units in the MC simulation. The parameter set thus obtained enabled the calculation of the state transition of each unit using the ODE model with reference to the neighboring states. The present ODE model not only provided good agreement with the MC simulation results but was also capable of reproducing a wide range of experimental results under both steady-state and dynamic conditions including shortening twitch. The simulation results suggested that the nearest-neighbor interaction is a reasonable approximation of the cooperativity based on end-to-end interactions. Utilizing the modified ODE model resulted in a reduction in computational costs but maintained spatial integrity and co-operative effects, making it a powerful tool in cardiac modeling