96 research outputs found
Imaging correlates of molecular signatures in oligodendrogliomas.
Molecular subsets of oligodendroglioma behave in biologically distinct ways. Their locations in the brain, rates of growth, and responses to therapy differ with their genotypes. Retrospectively, we inquired whether allelic loss of chromosomal arms 1p and 19q, an early molecular event and favorable prognostic marker in oligodendrogliomas, were reflected in their appearance on magnetic resonance imaging. Loss of 1p and 19q was associated with an indistinct border on T(1) images and mixed intensity signal on T(1) and T(2). Loss of 1p and 19q was also associated with paramagnetic susceptibility effect and with calcification, a common histopathological finding in oligodendrogliomas. These data encourage prospective evaluation of molecular alterations and magnetic resonance imaging characteristics of glial neoplasms
On Hilberg's Law and Its Links with Guiraud's Law
Hilberg (1990) supposed that finite-order excess entropy of a random human
text is proportional to the square root of the text length. Assuming that
Hilberg's hypothesis is true, we derive Guiraud's law, which states that the
number of word types in a text is greater than proportional to the square root
of the text length. Our derivation is based on some mathematical conjecture in
coding theory and on several experiments suggesting that words can be defined
approximately as the nonterminals of the shortest context-free grammar for the
text. Such operational definition of words can be applied even to texts
deprived of spaces, which do not allow for Mandelbrot's ``intermittent
silence'' explanation of Zipf's and Guiraud's laws. In contrast to
Mandelbrot's, our model assumes some probabilistic long-memory effects in human
narration and might be capable of explaining Menzerath's law.Comment: To appear in Journal of Quantitative Linguistic
The history of degenerate (bipartite) extremal graph problems
This paper is a survey on Extremal Graph Theory, primarily focusing on the
case when one of the excluded graphs is bipartite. On one hand we give an
introduction to this field and also describe many important results, methods,
problems, and constructions.Comment: 97 pages, 11 figures, many problems. This is the preliminary version
of our survey presented in Erdos 100. In this version 2 only a citation was
complete
Reversible Nanoparticle–Micelle Transformation of Ionic Liquid–Sulfonatocalix[6]arene Aggregates
The effect of temperature and NaCl concentration variations on the self-assembly of 1-methyl-3- tetradecylimidazolium (C14mim+) and 4-sulfonatocalix[6]-
arene (SCX6) was studied by dynamic light scattering and isothermal calorimetric methods at pH 7. Inclusion complex formation promoted the self-assembly to spherical nanoparticles (NP), which transformed to supramolecular micelles (SM) in the presence of NaCl. Highly reversible, temperature-responsive behavior was observed, and the conditions of the NP−SM transition could be tuned by the alteration of C14mim+:SCX6 mixing ratio and NaCl concentration. The association to SM was always exothermic with enthalpy independent of the amount of NaCl. In contrast, NPs were produced in endothermic process at low temperature, and the enthalpy change became less favorable upon increase in NaCl concentration. The NP formation was accompanied by negative molar heat capacity change, which further diminished when NaCl concentration was raised
Induction and transmission of oncogene-induced senescence
Senescence is a cellular stress response triggered by diverse stressors, including oncogene activation, where it serves as a bona-fide tumour suppressor mechanism. Senescence can be transmitted to neighbouring cells, known as paracrine secondary senescence. Secondary senescence was initially described as a paracrine mechanism, but recent evidence suggests a more complex scenario involving juxtacrine communication between cells. In addition, single-cell studies described differences between primary and secondary senescent end-points, which have thus far not been considered functionally distinct. Here we discuss emerging concepts in senescence transmission and heterogeneity in primary and secondary senescence on a cellular and organ level
Inducing institutional change through projects? : Three models of projectified governance
The study of short-term projects to implement policy has lately gained ground among scholars of environmental governance and public administration. The increasing reliance on and prevalence of projects, or ‘projectification’, has spurred critical debates on the ability of projects to contribute to long-term goals, including sustainability, as well as institutional change. Yet, the literature on projectification lacks specificity in terms of how projects are understood, how the relationship between projects and permanent organizations looks like, and how projects can influence institutional orders. The aim of this paper is to systematize the literature in order to uncover the process of transforming project outputs into institutional change. Three models of projectified governance – mechanistic, organic, and adaptive – is presented, providing a conceptual apparatus that advances the study of projects in environmental policy and governance. The paper argues that the adaptive model, with its reliance on multi-scalar networks for the coordination of project activities and knowledge, shows most promise in achieving institutional change to address complex environmental problems.Peer reviewe
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Comparative analysis of bones, mites, soil chemistry, nematodes and soil micro-Eukaryotes from a suspected homicide to estimate the post-mortem interval
Criminal investigations of suspected murder cases require estimating the post-mortem interval (PMI, or time after death) which is challenging for longer periods. Here we present the case of human remains found in a Swiss forest. We have used a multidisciplinary approach involving the analysis of bones, soil chemical characteristics, mites and nematodes (by microscopy) and micro-Eukaryotes (by Illumina high throughput sequencing). We analysed soil samples collected beneath the remains of the head, upper and lower body and “control” samples taken a few meters away. The PMI estimated on hair 14C-data via bomb peak radiocarbon dating gave a time range of 1 to 2 years before the finding of the remains on site. Cluster analyses for chemical constituents, nematodes, mites and micro- Eukaryotes revealed two clusters 1) head and upper body and 2) lower body and controls. From mite evidence, we conclude that the body was likely to have been brought to the site after death. However, chemical analyses, nematode community analyses and the analyses of micro-Eukaryotes indicate that decomposition took place at least partly on site. This study illustrates the usefulness of combining several lines of evidence for the study of homicide cases to better calibrate PMI inference tools
Mechanisms of progression of chronic kidney disease
Chronic kidney disease (CKD) occurs in all age groups, including children. Regardless of the underlying cause, CKD is characterized by progressive scarring that ultimately affects all structures of the kidney. The relentless progression of CKD is postulated to result from a self-perpetuating vicious cycle of fibrosis activated after initial injury. We will review possible mechanisms of progressive renal damage, including systemic and glomerular hypertension, various cytokines and growth factors, with special emphasis on the renin–angiotensin–aldosterone system (RAAS), podocyte loss, dyslipidemia and proteinuria. We will also discuss possible specific mechanisms of tubulointerstitial fibrosis that are not dependent on glomerulosclerosis, and possible underlying predispositions for CKD, such as genetic factors and low nephron number
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