Nonlinear finite element analysis of functionally graded circular plates with modified couple stress theory

Finite element models of microstructure-dependent geometrically nonlinear theories for axisymmetric bending of circular plates, which accounts for through-thickness power-law variation of a two constituent material, the von Karman nonlinearity, and the strain gradient effects are developed for the classical and first-order plate theories. The strain gradient effects are included through the modified couple stress theory that contains a single material length scale parameter which can capture the size effect in a functionally graded material plate. The developed finite element models are used to determine the effect of the geometric nonlinearity, power-law index, and microstructure-dependent constitutive relations on the bending response of functionally graded circular plates with different boundary conditions. (C) 2015 Elsevier Masson SAS. All rights reserved.AcknowledgmentsThefirst author gratefully acknowledges the support of thiswork by the FidiPro Professorship from Aalto University (Finland)and Chair of Excellence from University Carlos III of Madrid (Spain).The second author acknowledges the“Finland Distinguished Pro-fessor (FiDiPro) -program: Non-linear response of large, complexthin-walled structures”supported by Tekes and industrial partnersNapa, SSAB, Deltamarin, Koneteknologiakeskus Turku and MeyerTurku to Aalto University, while the third author gratefully ac-knowledges the support of the Chair of Excellence granted to thefirst author at University Carlos III of Madrid

Theories and analyses of functionally graded circular plates

This paper presents the governing equations and analytical solutions of the classical and shear deformation theories of functionally graded axisymmetric circular plates. The classical, first-order, and third-order shear deformation theories are presented, accounting for through-thickness variation of two-constituent functionally graded material, modified couple stress effect, and the von Kármán nonlinearity. Analytical solutions for bending of the linear theories, some of which are not readily available in the literature, are included to show the influence of the material variation, boundary conditions, and loads

Vacuum Expectation Value of the Spinor Massive field in the Cosmic String Space-Time

We found the contribution to the vacuum expectation value of the energy-momentum tensor of a massive Dirac field due to the conical geometry of the cosmic string space-time. The heat kernel and heat kernel expansion for the squared Dirac operator in this background are also considered and the first three coefficients were found in an explicity form.Comment: 9 pages, 1 figure (2 ref added) (enlarged version

Science, Diplomacy, and the Red Sea\u27s Unique Coral Reef: It\u27s Time for Action

Rapid ocean warming due to climate change poses a serious risk to the survival of coral reefs. It is estimated that 70–90 percent of all reefs will be severely degraded by mid-century even if the 1.5°C goal of the Paris Climate Agreement is achieved. However, one coral reef ecosystem seems to be more resilient to rising sea temperatures than most others. The Red Sea’s reef ecosystem is one of the longest continuous living reefs in the world, and its northernmost portion extends into the Gulf of Aqaba. The scleractinian corals in the Gulf have an unusually high tolerance for the rapidly warming seawater in the region. They withstand water temperature anomalies that cause severe bleaching or mortality in most hard corals elsewhere. This uniquely resilient reef employs biological mechanisms which are likely to be important for coral survival as the planet’s oceans warm. The Gulf of Aqaba could potentially be one of the planet’s largest marine refuges from climate change. However, this unique portion of the Red Sea’s reef will only survive and flourish if serious regional environmental challenges are addressed. Localized anthropogenic stressors compound the effects of warming seawater to damage corals and should be mitigated immediately. Reefs in the rest of the Red Sea are already experiencing temperatures above their thermal tolerance and have had significant bleaching, though they too would benefit from fewer local anthropogenic stressors. The countries bordering the entire Red Sea will need to cooperate to enable effective scientific research and conservation. The newly established Transnational Red Sea Center, based at the Ecole Polytechnique Fédérale de Lausanne (EPFL), can serve as the regionally inclusive, neutral organization to foster crucial regional scientific collaboration

A novel digital score for abundance of tumour infiltrating lymphocytes predicts disease free survival in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common type of head and neck (H&N) cancers with an increasing worldwide incidence and a worsening prognosis. The abundance of tumour infiltrating lymphocytes (TILs) has been shown to be a key prognostic indicator in a range of cancers with emerging evidence of its role in OSCC progression and treatment response. However, the current methods of TIL analysis are subjective and open to variability in interpretation. An automated method for quantification of TIL abundance has the potential to facilitate better stratification and prognostication of oral cancer patients. We propose a novel method for objective quantification of TIL abundance in OSCC histology images. The proposed TIL abundance (TILAb) score is calculated by first segmenting the whole slide images (WSIs) into underlying tissue types (tumour, lymphocytes, etc.) and then quantifying the co-localization of lymphocytes and tumour areas in a novel fashion. We investigate the prognostic significance of TILAb score on digitized WSIs of Hematoxylin and Eosin (H&E) stained slides of OSCC patients. Our deep learning based tissue segmentation achieves high accuracy of 96.31%, which paves the way for reliable downstream analysis. We show that the TILAb score is a strong prognostic indicator (p = 0.0006) of disease free survival (DFS) on our OSCC test cohort. The automated TILAb score has a significantly higher prognostic value than the manual TIL score (p = 0.0024). In summary, the proposed TILAb score is a digital biomarker which is based on more accurate classification of tumour and lymphocytic regions, is motivated by the biological definition of TILs as tumour infiltrating lymphocytes, with the added advantages of objective and reproducible quantification

Functional determinants for general self-adjoint extensions of Laplace-type operators resulting from the generalized cone

In this article we consider the zeta regularized determinant of Laplace-type operators on the generalized cone. For {\it arbitrary} self-adjoint extensions of a matrix of singular ordinary differential operators modelled on the generalized cone, a closed expression for the determinant is given. The result involves a determinant of an endomorphism of a finite-dimensional vector space, the endomorphism encoding the self-adjoint extension chosen. For particular examples, like the Friedrich's extension, the answer is easily extracted from the general result. In combination with \cite{BKD}, a closed expression for the determinant of an arbitrary self-adjoint extension of the full Laplace-type operator on the generalized cone can be obtained.Comment: 27 pages, 2 figures; to appear in Manuscripta Mathematic

Sexual Plasticity and Self-Fertilization in the Sea Anemone Aiptasia diaphana

Traits that influence reproductive success and contribute to reproductive isolation in animal and plant populations are a central focus of evolutionary biology. In the present study we used an experimental approach to demonstrate the occurrence of environmental effects on sexual and asexual reproduction, and provide evidence for sexual plasticity and inter-clonal fertilization in laboratory-cultured lines of the sea anemone Aiptasia diaphana. We showed that in A. diaphana, both asexual reproduction by pedal laceration, and sexual reproduction have seasonal components. The rate of pedal laceration was ten-fold higher under summer photoperiod and water temperature conditions than under winter conditions. The onset of gametogenesis coincided with the rising water temperatures occurring in spring, and spawning occurred under parameters that emulated summer photoperiod and temperature conditions. In addition, we showed that under laboratory conditions, asexually produced clones derived from a single founder individual exhibit sexual plasticity, resulting in the development of both male and female individuals. Moreover, a single female founder produced not only males and females but also hermaphrodite individuals. We further demonstrated that A. diaphana can fertilize within and between clone lines, producing swimming planula larvae. These diverse reproductive strategies may explain the species success as invader of artificial marine substrates. We suggest that these diverse reproductive strategies, together with their unique evolutionary position, make Aiptasia diaphana an excellent model for studying the evolution of sex

Concurrent use of prescription drugs and herbal medicinal products in older adults: A systematic review

This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), which permits any noncommercial use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.The use of herbal medicinal products (HMPs) is common among older adults. However, little is known about concurrent use with prescription drugs as well as the potential interactions associated with such combinations. Objective Identify and evaluate the literature on concurrent prescription and HMPs use among older adults to assess prevalence, patterns, potential interactions and factors associated with this use. Methods Systematic searches in MEDLINE, PsycINFO, EMBASE, CINAHL, AMED, Web of Science and Cochrane from inception to May 2017 for studies reporting concurrent use of prescription medicines with HMPs in adults (≥65 years). Quality was assessed using the Joanna Briggs Institute checklists. The Evidence for Policy and Practice Information and Co-ordinating Centre (EPPI-Centre) three stage approach to mixed method research was used to synthesise data. Results Twenty-two studies were included. A definition of HMPs or what was considered HMP was frequently missing. Prevalence of concurrent use by older adults varied widely between 5.3% and 88.3%. Prescription medicines most combined with HMPs were antihypertensive drugs, beta blockers, diuretics, antihyperlipidemic agents, anticoagulants, analgesics, antihistamines, antidiabetics, antidepressants and statins. The HMPs most frequently used were: ginkgo, garlic, ginseng, St John’s wort, Echinacea, saw palmetto, evening primrose oil and ginger. Potential risks of bleeding due to use of ginkgo, garlic or ginseng with aspirin or warfarin was the most reported herb-drug interaction. Some data suggests being female, a lower household income and less than high school education were associated with concurrent use. Conclusion Prevalence of concurrent prescription drugs and HMPs use among older adults is substantial and potential interactions have been reported. Knowledge of the extent and manner in which older adults combine prescription drugs will aid healthcare professionals can appropriately identify and manage patients at risk.Peer reviewedFinal Published versio

A digital score of tumour‐associated stroma infiltrating lymphocytes predicts survival in head and neck squamous cell carcinoma

The infiltration of T-lymphocytes in the stroma and tumour is an indication of an effective immune response against the tumour, resulting in better survival. In this study, our aim was to explore the prognostic significance of tumour-associated stroma infiltrating lymphocytes (TASILs) in head and neck squamous cell carcinoma (HNSCC) through an AI-based automated method. A deep learning-based automated method was employed to segment tumour, tumour-associated stroma, and lymphocytes in digitally scanned whole slide images of HNSCC tissue slides. The spatial patterns of lymphocytes and tumour-associated stroma were digitally quantified to compute the tumour-associated stroma infiltrating lymphocytes score (TASIL-score). Finally, the prognostic significance of the TASIL-score for disease-specific and disease-free survival was investigated using the Cox proportional hazard analysis. Three different cohorts of haematoxylin and eosin (H&E)-stained tissue slides of HNSCC cases (n = 537 in total) were studied, including publicly available TCGA head and neck cancer cases. The TASIL-score carries prognostic significance (p = 0.002) for disease-specific survival of HNSCC patients. The TASIL-score also shows a better separation between low- and high-risk patients compared with the manual tumour-infiltrating lymphocytes (TILs) scoring by pathologists for both disease-specific and disease-free survival. A positive correlation of TASIL-score with molecular estimates of CD8+ T cells was also found, which is in line with existing findings. To the best of our knowledge, this is the first study to automate the quantification of TASILs from routine H&E slides of head and neck cancer. Our TASIL-score-based findings are aligned with the clinical knowledge, with the added advantages of objectivity, reproducibility, and strong prognostic value. Although we validated our method on three different cohorts (n = 537 cases in total), a comprehensive evaluation on large multicentric cohorts is required before the proposed digital score can be adopted in clinical practice

Deep reefs of the Great Barrier Reef offer limited thermal refuge during mass coral bleaching

Our rapidly warming climate is threatening coral reefs as thermal anomalies trigger mass coral bleaching events. Deep (or "mesophotic") coral reefs are hypothesised to act as major ecological refuges from mass bleaching, but empirical assessments are limited. We evaluated the potential of mesophotic reefs within the Great Barrier Reef (GBR) and adjacent Coral Sea to act as thermal refuges by characterising long-term temperature conditions and assessing impacts during the 2016 mass bleaching event. We found that summer upwelling initially provided thermal relief at upper mesophotic depths (40 m), but then subsided resulting in anomalously warm temperatures even at depth. Bleaching impacts on the deep reefs were severe (40% bleached and 6% dead colonies at 40 m) but significantly lower than at shallower depths (60-69% bleached and 8-12% dead at 5-25 m). While we confirm that deep reefs can offer refuge from thermal stress, we highlight important caveats in terms of the transient nature of the protection and their limited ability to provide broad ecological refuge.XL Catlin Seaview Survey; Waitt Foundation; XL Catlin Group; Underwater Earth; University of Queensland; ARC Discovery Early Career Researcher Award (DECRA) [DE160101433]; Portuguese Science and Technology Foundation (FCT) [SFRH/BPD/110285/2015]; Australian Research Council (ARC