976 research outputs found
Cell Cycle Regulation of Stem Cells by MicroRNAs
MicroRNAs (miRNAs) are a class of small non-coding RNA molecules involved in the regulation of gene expression. They are involved in the fine-tuning of fundamental biological processes such as proliferation, differentiation, survival and apoptosis in many cell types. Emerging evidence suggests that miRNAs regulate critical pathways involved in stem cell function. Several miRNAs have been suggested to target transcripts that directly or indirectly coordinate the cell cycle progression of stem cells. Moreover, previous studies have shown that altered expression levels of miRNAs can contribute to pathological conditions, such as cancer, due to the loss of cell cycle regulation. However, the precise mechanism underlying miRNA-mediated regulation of cell cycle in stem cells is still incompletely understood. In this review, we discuss current knowledge of miRNAs regulatory role in cell cycle progression of stem cells. We describe how specific miRNAs may control cell cycle associated molecules and checkpoints in embryonic, somatic and cancer stem cells. We further outline how these miRNAs could be regulated to influence cell cycle progression in stem cells as a potential clinical application
Validating and Improving Models for Vibratory Installation of Steel Sheet Piles with Field Observations
Квир-лингвистика: нужна ли она отечественной лингвистической гендерологии?
Статья посвящена квир-лингвистике как новому магистральному направлению развития современной парадигмы гендерных исследований. Подробно разбирается концептуальный аппарат этого направления. Описывается попытка изучения фрагментов языкового сознания носителей русского языка с учетом квир-фактора.Стаття присвячена квір-лінгвістиці як новому магістральному напрямку в розвитку сучасної парадигми гендерних досліджень. Докладно розбирається концептуальний апарат цього напрямку. Описується спроба вивчення фрагментів мовної свідомості носіїв російської мови з урахуванням квір-фактору.The article is targeted at a new discipline in the area of gender and language research – queer linguistics. The conceptual linguistic apparatus and terminology are discussed. The study of verbal responses obtained from Russian –speaking informants (gays and lesbians) as a linguistic construal of their world is analyzed
Methods and tools supporting urban resilience planning: experiences from Cork, Ireland
To prevent flood disasters, policymakers call for resilient cities which are better able to cope with flood hazards. However, actual adoption of resilience measures in urban planning is still limited, partly because it is not sufficiently clear how and to what extent resilience should and can be enhanced. To develop resilience strategies, information on the current resilience and on the effects of measures should be available. Since cities are complex systems, an assessment of resilience requires the input of different actors. To obtain and combine this input, a comprehensive approach which brings together many actors is required. Furthermore, resilience must be integrated in planning frameworks in order to enhance adoption by city policy makers. Tools which support and structure the contribution of different disciplines and actors will help to obtain information on the current resilience and to develop a shared vision on measures to enhance urban resilience. We illustrate our view with an example on Cork, Ireland
Geobrain: Dutch Feasibility Database for Installing Sheet Pile Walls
In this paper it is shown how the knowledge embedded in case histories can be used to explicate some of the uncertainties contributing to the gap between theory and practice. With the help of computational intelligence techniques, collections of case histories in data-bases, as a type of collective memory of the geotechnical profession may be explored to turn this memory into collective brains in geo-technics: a GeoBrain. Regarding the scarcity of soil investigation data and the translation of the available data into a model, the ‘schematization factor’ has been introduced as a partial safety factor to account for the influence of data availability and the role of human expertise. Using a database of increasing size on the feasibility of installing sheet pile walls, the determination of optimal parameter values for prediction models is illustrated. It is shown that computational intelligence techniques like Bayesian Belief Networks and Genetic Algorithms can be very helpful to improve predictions of what is likely to happen in geotechnical practice
Methods and tools supporting urban resilience planning: experiences from Cork, Ireland
To prevent flood disasters, policymakers call for resilient cities which are better able to cope with flood hazards. However, actual adoption of resilience measures in urban planning is still limited, partly because it is not sufficiently clear how and to what extent resilience should and can be enhanced. To develop resilience strategies, information on the current resilience and on the effects of measures should be available. Since cities are complex systems, an assessment of resilience requires the input of different actors. To obtain and combine this input, a comprehensive approach which brings together many actors is required. Furthermore, resilience must be integrated in planning frameworks in order to enhance adoption by city policy makers. Tools which support and structure the contribution of different disciplines and actors will help to obtain information on the current resilience and to develop a shared vision on measures to enhance urban resilience. We illustrate our view with an example on Cork, Ireland
Antiviral Effect of Ribavirin against HCV Associated with Increased Frequency of G-to-A and C-to-U Transitions in Infectious Cell Culture Model
Abstract Ribavirin (RBV) is a broad-spectrum antiviral active against a wide range of RNA viruses. Despite having been used for decades in the treatment of chronic hepatitis C virus (HCV) infection, the precise mechanism of action of RBV is unknown. In other viruses, it inhibits propagation by increasing the rate of G-to-A and C-to-U transitions. Here, we utilized the J6/JFH1 HCV cell-culture system to investigate whether RBV inhibits HCV through the same mechanism. Infected Huh7.5 cells were treated with increasing concentrations of RBV or its phosphorylated forms. A fragment of the HCV NS5B-polymerase gene was amplified, cloned, and sequenced to estimate genetic distances. We confirm that the antiviral effect of all three RBV-drug forms on HCV relies on induction of specific transitions (G-to-A and C-to-U). These mutations lead to generation of non-infectious virions, reflected by decreased spread of HCV in cell culture despite relatively limited effect on virus genome titers. Moreover, treatment experiments conducted on a novel Huh7.5 cell line stably overexpressing adenosine kinase, a key enzyme for RBV activation, yielded comparable results. This study indicates that RBV action on HCV in hepatoma cell-culture is exerted through increase in mutagenesis, mediated by RBV triphosphate, and leading to production of non-infectious viruses
Engaging without over-powering: A case study of a FLOSS project
This is the post-print version of the published chapter. The original publication is available at the link below. Copyright @ 2010 IFIP International Federation for Information Processing.The role of Open Source Software (OSS) in the e-learning business has become more and more fundamental in the last 10 years, as long as corporate and government organizations have developed their educational and training programs based on OSS out-of-the-box tools. This paper qualitatively documents the decision of the largest UK e-learning provider, the Open University, to adopt the Moodle e-learning system, and how it has been successfully deployed in its site after a multi-million investment. A further quantitative study also provides evidence of how a commercial stakeholder has been engaged with, and produced outputs for, the Moodle community. Lessons learned from this experience by the stakeholders include the crucial factors of contributing to the OSS community, and adapting to an evolving technology. It also becomes evident how commercial partners helped this OSS system to achieve the transition from an “average” OSS system to a successful multi-site, collaborative and community-based OSS project
Refactoring preserves security
Refactoring allows changing a program without changing its behaviour from an observer’s point of view. To what extent does this invariant of behaviour also preserve security? We show that a program remains secure under refactoring. As a foundation, we use the Decentralized Label Model (DLM) for specifying secure information flows of programs and transition system models for their observable behaviour. On this basis, we provide a bisimulation based formal definition of refactoring and show its correspondence to the formal notion of information flow security (noninterference). This permits us to show security of refactoring patterns that have already been practically explored
Variation in carbon footprint of milk due to management differences between Swedish dairy farms
To identify mitigation options to reduce greenhouse gas (GHG) emissions from milk production (i.e. the carbon footprint (CF) of milk), this study examined the variation in GHG emissions among dairy farms using data from previous CF studies on Swedish milk. Variation between farms in these production data, which were found to have a strong influence on milk CF were obtained from existing databases of e.g. 1051 dairy farms in Sweden in 2005. Monte Carlo analysis was used to analyse the impact of variations in seven important parameters on milk CF concerning milk yield (energy corrected milk (ECM) produced and delivered), feed dry matter intake (DMI), enteric methane emissions, N content in feed DMI, N-fertiliser rate and diesel used on farm. The largest between farm variation among the analysed production data were N-fertiliser rate (kg/ha) and diesel used (l/ha) on farm (coefficient of variation (CV) 31-38%). For the parameters concerning milk yield and feed DMI the CV was approx. 11 and 8%, respectively. The smallest variation in production data was found for N content in feed DMI. According to the Monte Carlo analysis, these variations in production data led to a variation in milk CF of between 0.94 and 1.33 kg CO2 equivalents (CO2e) per kg ECM, with an average value of 1.13 kg/CO2e kg ECM. We consider that this variation of ±17% that was found based on the used farm data would be even greater if all Swedish dairy farms were included, as the sample of farms in this study was not totally unbiased. The variation identified in milk CF indicates that a potential exists to reduce GHG emissions from milk production on both national and farm level through changes in management. As milk yield and feed DMI are two of the most influential parameters for milk CF, feed conversion efficiency (i.e. units ECM produced per unit DMI) can be used as a rough key performance indicator for predicting CF reductions. However, it must be borne in mind that feeds have different CF due to where and how they are produced
- …