974 research outputs found

    Advances in modelling of epithelial to mesenchymal transition

    Get PDF
    Epithelial to Mesenchymal Transition (EMT) is a cellular transformation process that is employed repeatedly and ubiquitously during vertebrate morphogenesis to build complex tissues and organs. Cellular transformations that occur during cancer cell invasion are phenotypically similar to developmental EMT, and involve the same molecular signalling pathways. EMT processes are diverse, but are characterised by: a loss of cell-cell adhesion; a gain in cell-matrix adhesion; an increase in cell motility; the secretion of proteases that degrade basement membrane proteins; an increased resistance to apoptosis; a loss of polarisation; increased production of extracellular matrix components; a change from a rounded to a fibroblastic morphology; and an invasive phenotype. This thesis focuses explicitly on endocardial EMT, which is the EMT that occurs during vertebrate embryonic heart development. The embryonic heart initially forms as a tube, with myocardium externally, endocardium internally, with these tissue layers separated by a thick extracellular matrix termed the cardiac jelly. Some of the endocardial cells in specific regions of the embryonic heart tube undergo EMT and invade the cardiac jelly. This causes cellularised swellings inside the embryonic heart tube termed the endocardial cushions. The emergence of the four chambered double pump heart of mammals involves a complex remodelling that the endocardial cushions play an active role in. Even while heart remodelling is taking place, the heart tube is operating as a single-circulation pump, and the endocardial cushions are performing a valve-like function that is critical to the survival of the embryo (Nomura-Kitabayashi et al. 2009). As the endocardial cushions grow and remodel, they become the valve leaflets of the foetal heart. The endocardial cushions also contribute tissue to the septa (walls) of the heart. Their correct formation is thus essential to the development of a fully functional, fully divided, double-pump system. It has been shown that genetic mutations that cause impaired endocardial EMT lead to the development of a range of congenital heart defects (Fischer et al. 2007). An extensive review is conducted of existing experimental investigations into endocardial EMT. The information extracted from this review is used to develop a multiscale conceptual model of endocardial EMT, including the major protein signalling pathways involved, and the cellular phenotypes that they induce or inhibit. After considering the requirements for computational simulations of EMT, and reviewing the various techniques and simulation packages available for multi-cell modelling, cellular Potts modelling is selected as having the most appropriate combination of features. The open source simulation platform Compucell3D is selected for model development, due to the flexibility, range of features provided and an existing implementation of multiscale models; that include subcellular models of reaction pathways. Based on the conceptual model of endocardial EMT, abstract computational simulations of key aspects are developed, in order to investigate qualitative behaviour under different simulated conditions. The abstract simulations include a 2D multiscale model of Notch signalling lateral induction, which is the mechanism by which the embryonic heart tube is patterned into cushion and non-cushion forming regions. Additionally, a 3D simulation is used to investigate the possible role of contact-inhibited mitosis, upregulated by the VEGF protein, in maintaining an epithelial phenotype. One particular in vitro investigation of endocardial EMT (Luna-Zurita et al. 2010) is used to develop quantitative simulations. The quantitative data used for fitting the simulations consist of cell shape metrics that are derived from simple processing of the imaging results. Single cell simulations are used to investigate the relationship between cell motility and cell shape in the cellular Potts model. The findings are then implemented in multi-cell models, in order to investigate the relationship between cell-cell adhesion, cell-matrix adhesion, cell motility and cell shape during EMT

    Sexual Deviations from Islamic Perspective: Sexual Harassment as An Example

    Get PDF
    This research addresses the pressing global issue of sexual harassment by examining its prevalence and underlying factors. Drawing on international data, our study reveals alarming rates of sexual harassment in various contexts, emphasizing its urgency. Employing a descriptive analysis method, the research investigates the motives and consequences of this behavioral deviation. Findings underscore the roles of education, economics, and the absence of a proper Islamic perspective on sexuality in perpetuating harassment. Educational institutions emerge as pivotal in both occurrence and prevention, while media portrayal of women and insufficient sexual education contribute to societal deviations. The study highlights the multifaceted impact of harassment on mental well-being and advocates for effective punitive measures to curb sexual deviancy and restore social harmony

    Napredak koncepta višerazinskog sustavskog inženjerstva u razumijevanju srčanog razvoja

    Get PDF
    Multiscale systems engineering provides a way to integrate models of real-world phenomena that allows a holistic understanding of component interactions at different levels of scale simultaneously. The discipline draws upon information engineering to provide ontological representations that are derived from digital libraries of terms, them-selves found at distributed locations around the world. Cardiac development is well understood within discrete levels of analysis. The application of the multiscale framework gives added value by unlocking the relationships between genetic-based information at one level of analysis and the phenotype it encodes for at the cell and organ levels of abstraction. The multiscale-based relationships have begun to demonstrate new insights into normal cardiac development and conditions that give rise to congenital heart diseases such as the tetralogy of Fallot. This paper describes progress made in combining ontology-based information models and explains the importance of the role of multiscale systems engineering.Višerazinsko sustavsko inženjerstvo pruža mogućnost integracije modela različitih pojava iz stvarnog svijeta, što omogućuje cjelovito razumijevanje interakcija komponenti sustava istovremeno na različitim razinama skale. Disciplina je to koja koristi informatiku za omogućavanje ontoloških reprezentacija koje se izvode iz digitalnih knjižnica pojmova smještenih na raspodijeljnim lokacijama širom svijeta. Unutar pojedinačnih razina analize postoji dobro razmijevanje srčanog razvoja. Primjena višerazinskog okvira daje dodatnu vrijednost otključavajući vezu između genetski temeljenih informacija na jednoj razini analize i fenotipa koji kodira na razinama apstrakcije stanice i organa. Višerazinski temeljene veze počele su donositi nove spoznaje normalnog srčanog razvoja i uvjeta koji vode k pojavi prirođenih srčanih grešaka kao što je Fallotova tetralogija. Ovaj rad opisuje napredak postignut kombiniranjem ontologijski temeljenih infomacijskih modela i objašnjava važnost uloge višerazinskog sustavskog inženjerstva

    Multiscale information modelling for heart morphogenesis

    Get PDF
    Science is made feasible by the adoption of common systems of units. As research has become more data intensive, especially in the biomedical domain, it requires the adoption of a common system of information models, to make explicit the relationship between one set of data and another, regardless of format. This is being realised through the OBO Foundry to develop a suite of reference ontologies, and NCBO Bioportal to provide services to integrate biomedical resources and functionality to visualise and create mappings between ontology terms. Biomedical experts tend to be focused at one level of spatial scale, be it biochemistry, cell biology, or anatomy. Likewise, the ontologies they use tend to be focused at a particular level of scale. There is increasing interest in a multiscale systems approach, which attempts to integrate between different levels of scale to gain understanding of emergent effects. This is a return to physiological medicine with a computational emphasis, exemplified by the worldwide Physiome initiative, and the European Union funded Network of Excellence in the Virtual Physiological Human. However, little work has been done on how information modelling itself may be tailored to a multiscale systems approach. We demonstrate how this can be done for the complex process of heart morphogenesis, which requires multiscale understanding in both time and spatial domains. Such an effort enables the integration of multiscale metrology

    Prostate cancer metastases to the rectum: A case report

    Get PDF
    Prostate cancer rarely metastasis to the rectum. Findings in the patient reported here emphasize the importance of the relationship between urinary and gastrointestinal symptoms in detecting prostatic neoplasms in older male patients

    Metarhizium anisopliae Pathogenesis of Mosquito Larvae: A Verdict of Accidental Death

    Get PDF
    Metarhizium anisopliae, a fungal pathogen of terrestrial arthropods, kills the aquatic larvae of Aedes aegypti, the vector of dengue and yellow fever. The fungus kills without adhering to the host cuticle. Ingested conidia also fail to germinate and are expelled in fecal pellets. This study investigates the mechanism by which this fungus adapted to terrestrial hosts kills aquatic mosquito larvae. Genes associated with the M. anisopliae early pathogenic response (proteinases Pr1 and Pr2, and adhesins, Mad1 and Mad2) are upregulated in the presence of larvae, but the established infection process observed in terrestrial hosts does not progress and insecticidal destruxins were not detected. Protease inhibitors reduce larval mortality indicating the importance of proteases in the host interaction. The Ae. aegypti immune response to M. anisopliae appears limited, whilst the oxidative stress response gene encoding for thiol peroxidase is upregulated. Cecropin and Hsp70 genes are downregulated as larval death occurs, and insect mortality appears to be linked to autolysis through caspase activity regulated by Hsp70 and inhibited, in infected larvae, by protease inhibitors. Evidence is presented that a traditional host-pathogen response does not occur as the species have not evolved to interact. M. anisopliae retains pre-formed pathogenic determinants which mediate host mortality, but unlike true aquatic fungal pathogens, does not recognise and colonise the larval host

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

    Get PDF
    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

    Full text link
    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

    Get PDF
    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI
    corecore