Search results for "Secondary"
showing 10 items of 1765 documents
Modeling multiple taxis: Tumor invasion with phenotypic heterogeneity, haptotaxis, and unilateral interspecies repellence
2021
We provide a short review of existing models with multiple taxis performed by (at least) one species and consider a new mathematical model for tumor invasion featuring two mutually exclusive cell phenotypes (migrating and proliferating). The migrating cells perform nonlinear diffusion and two types of taxis in response to non-diffusing cues: away from proliferating cells and up the gradient of surrounding tissue. Transitions between the two cell subpopulations are influenced by subcellular (receptor binding) dynamics, thus conferring the setting a multiscale character. We prove global existence of weak solutions to a simplified model version and perform numerical simulations for the full se…
Antiproliferative activity against leukemia cells of sesquiterpene lactones from the Turkish endemic plant Centaurea drabifolia subsp. detonsa
2017
The apolar organic extract obtained from aerial parts of Centaurea drabifolia Sibth. & Sm. subsp. detonsa (Bornm.) Wagenitz, growing wild in Turkey, was investigated for the first time for its secondary metabolite composition. Seven sesquiterpene lactones belonging to the guaiane class (1-7), including the new compound 4, along with a fatty acid lactone derivative (8), were isolated. The structures of these compounds were established by spectroscopic analysis, including 2D NMR spectroscopic techniques, with the stereostructure of the new guaiane 4 determined with the help of MTPA derivatization. Cytotoxic activities of compounds 1-7 were evaluated against two cancer cell lines, namely acute…
JSSPrediction: a Framework to Predict Protein Secondary Structures Using Integration
2006
Identifying protein secondary structures is a difficult task. Recently, a lot of software tools for protein secondary structure prediction have been produced and made available on-line, mostly with good performances. However, prediction tools work correctly for families of proteins, such that users have to know which predictor to use for a given unknown protein. We propose a framework to improve secondary structure prediction by integrating results obtained from a set of available predictors. Our contribution consists in the definition of a two phase approach: (i) select a set of predictors which have good performances with the unknown protein family, and (ii) integrate the prediction resul…
Framing issues in the public debate: the case of human rights
2013
PurposeThe purpose of this paper is to better understand how issues may be framed in public debate. The outcomes of this debate affect organizations. The study is based on the seven types of framing identified by Hallahan and scrutinizes which of these types is utilized, and how this is done, in the case of human rights issues.Design/methodology/approachFor this study a secondary analysis of academic papers on human rights issues was conducted. After a literature search, 40 papers originating from 23 different journals were further analyzed. Where the researchers described the framing of human rights issues, the type of framing was identified according to the typology and mode of utilizatio…
Carnaval y música: una breve semblanza de la Tuna Compostelana de 1888
2021
At the end of the 19th century, Spanish carnivals have been marked by the participation of the different tunas or also known as, estudiantinas. These groups achieved significant relevance in Galicia, especially in the city of Compostela, which, year after year, encouraged and supported the formation of groups of this nature to liven up the carnivals in the different Spanish cities. Although, different from its predecessors, the Santiago Tuna of 1888 ventured and made its mark in history, thanks to its intrepidity in having been the first Galician group that crossed the borders and enlivened the carnivals in the cities of the neighboring country, Portugal. This research, approached from a hi…
The obstacles to the development of secondary education in Spain, 1857-1900
2023
Human capital is one of the pillars of economic growth and development. However, the economic analysis of human capital presents a large number of difficulties, especially since the mechanisms that allow the accumulation of this type of capital, skills and knowledge, are intrinsic to human nature and, in general, are difficult to determine. But, in addition, the formation of human capital results from formal and informal learning and occurs throughout life, so its measurement is a challenge. Trying to overcome the drawbacks that the analysis of human capital poses, some researchers have proposed the differentiation of human capital into types or levels in order to see its differential effec…
Growth and defense in deciduous trees and shrubs under UV-B
2005
Abstract Reflection by waxy or resinous surface structures and hairs, repair reactions of biomolecules and induction of different sheltering components provide the means of plant protection from harmful solar UV-B radiation. Secondary products, especially flavonoids and phenolic acids as defense components are also important in plant tolerance to UV-B, fulfilling the dual role as screens that reduce UV-B penetration in plant tissues, and as antioxidants protecting from damage by reactive oxidant species. Plants are sensitive to UV-B radiation, and this sensitivity can be even more clone-specific than species-specific. The results available in the literature for deciduous trees and shrubs in…
Factorization of strongly (p,sigma)-continuous multilinear operators
2013
We introduce the new ideal of strongly-continuous linear operators in order to study the adjoints of the -absolutely continuous linear operators. Starting from this ideal we build a new multi-ideal by using the composition method. We prove the corresponding Pietsch domination theorem and we present a representation of this multi-ideal by a tensor norm. A factorization theorem characterizing the corresponding multi-ideal - which is also new for the linear case - is given. When applied to the case of the Cohen strongly -summing operators, this result gives also a new factorization theorem.
Rescaling principle for isolated essential singularities of quasiregular mappings
2012
We establish a rescaling theorem for isolated essential singularities of quasiregular mappings. As a consequence we show that the class of closed manifolds receiving a quasiregular mapping from a punctured unit ball with an essential singularity at the origin is exactly the class of closed quasiregularly elliptic manifolds, that is, closed manifolds receiving a non-constant quasiregular mapping from a Euclidean space.
Secondary structure determination of conserved SARS-CoV-2 RNA elements by NMR spectroscopy
2020
AbstractThe current pandemic situation caused by the Betacoronavirus SARS-CoV-2 (SCoV2) highlights the need for coordinated research to combat COVID-19. A particularly important aspect is the development of medication. In addition to viral proteins, structured RNA elements represent a potent alternative as drug targets. The search for drugs that target RNA requires their high-resolution structural characterization. Using nuclear magnetic resonance (NMR) spectroscopy, a worldwide consortium of NMR researchers aims to characterize potential RNA drug targets of SCoV2. Here, we report the characterization of 15 conserved RNA elements located at the 5′ end, the ribosomal frameshift segment and t…