180 research outputs found
Citicoline (Cognizin) in the treatment of cognitive impairment
Pharmacological treatment of cerebrovascular disorders was introduced at the beginning of the 20th Century. Since then, a multitude of studies have focused on the development of a consensus for a well defined taxonomy of these disorders and on the identification of specific patterns of cognitive deficits associated with them, but with no clear consensus. Nevertheless, citicoline has proved to be a valid treatment in patients with a cerebrovascular pathogenesis for memory disorders. A metanalysis performed on the entire database available from the clinical studies performed with this compound confirms the experimental evidence from the animal studies which have repeatedly described the multiple biological actions of citicoline in restoring both the cell lipid structures and some neurotransmitter functions
Algebro-geometric analysis of bisectors of two algebraic plane curves
In this paper, a general theoretical study, from the perspective of the algebraic geometry, of the untrimmed bisector of two real algebraic plane curves is presented. The curves are considered in C2, and the real bisector is obtained by restriction to R2. If the implicit equations of the curves are given, the equation of the bisector is obtained by projection from a variety contained in C7, called the incidence variety, into C2. It is proved that all the components of the bisector have dimension 1. A similar method is used when the curves are given by parametrizations, but in this case, the incidence variety is in C5. In addition, a parametric representation of the bisector is introduced, as well as a method for its computation. Our parametric representation extends the representation in Farouki and Johnstone (1994b) to the case of rational curves
MaTeX: libro digital de matemáticas
En el presente artículo se presenta MaTeX, un libro digital de matemáticas para alumnos de primero de ESO y para alumnos de segundo de ESO en el que, mediante una interfaz muy sencilla, se muestra el contenido, compuesto tanto de aspectos teóricos como de ejemplos, ejercicios y tests aleatorios. Para su utilización no se requiere de ninguna instalación ya que se utiliza vía web por navegador. Entre sus principales ventajas destaca su facilidad de uso, que fomenta la autonomía del aprendizaje y posibilita distintos ritmos de trabajo, permitiendo gestionar la evaluación de los alumnos a través de una base de datos
On the implicit equation of conics and quadrics offsets
A new determinantal representation for the implicit equation of offsets to conics and quadrics is derived. It is simple, free of extraneous components and provides a very compact expanded form, these representations being very useful when dealing with geometric queries about offsets such as point positioning or solving intersection purposes. It is based on several classical results in ?A Treatise on the Analytic Geometry of Three Dimensions? by G. Salmon for offsets to non-degenerate conics and central quadrics.This research was funded by the Spanish Ministerio de Economía y Competitividad and by the European Regional Development Fund (ERDF), under the project MTM2017-88796-P
Offsets to conics and quadrics: a new determinantal representation for their implicit equation
A new determinantal presentation of the implicit equation for offsets to non degenerate conics and quadrics is introduced which is specially well suited for intersection purposes
Dirofilaria repens testicular infection in child, Italy
Testicular Dirofilaria repens infection was identified and confirmed by sequence analysis in a child in northeastern Italy. Because human dirofilariasis is emerging in southern and eastern Europe, this parasitic infection should be considered in the differential diagnosis of scrotal swelling in disease-endemic countries to avoid unnecessary interventions, such as orchiectomy
Using implicit equations of parametric curves and surfaces without computing them: Polynomial algebra by values
The availability of the implicit equation of a plane curve or of a 3D surface can be very useful in order to solve many geometric problems involving the considered curve or surface: for example, when dealing with the point position problem or answering intersection questions. On the other hand, it is well known that in most cases, even for moderate degrees, the implicit equation is either difficult to compute or, if computed, the high degree and the big size of the coefficients makes extremely difficult its use in practice.
We will show that, for several problems involving plane curves, 3D surfaces and some of their constructions (for example, offsets), it is possible to use the implicit equation (or, more precisely, its properties) without needing to explicitly determine it. We replace the computation of the implicit equation with the evaluation of the considered parameterizations in a set of points. We then translate the geometric problem in hand, into one or several generalized eigenvalue problems on matrix pencils (depending again on several evaluations of the considered parameterizations).
This is the so-called “polynomial algebra by values” approach where the huge polynomial equations coming from Elimination Theory (e.g., using resultants) are replaced by big structured and sparse numerical matrices. For these matrices there are well-known numerical techniques allowing to provide the results we need to answer the geometric questions on the considered curves and surfaces
Novel Pyridine-Based Hydroxamates and 2'-Aminoanilides as Histone Deacetylase Inhibitors: Biochemical Profile and Anticancer Activity
Starting from the N-hydroxy-3-(4-(2-phenylbutanoyl)amino)phenyl)acrylamide 5b previously described by us as HDAC inhibitor, we prepared four aza-analogues of 5b (6-8, 9b) as regioisomers containing the pyridine nucleus. A preliminary screening against mHDAC1 highlighted the N-hydroxy-5-(2-(2-phenylbutanoyl)amino)pyridyl)acrylamide 9b as the most potent inhibitor. Thus, we further developed both pyridylacrylic- and nicotinic-based hydroxamates (9a, 9c-f, and 11a-f) and 2'-aminoanilides (10a-f and 12a-f), related to 9b, to be tested against HDACs. Among them, the nicotinic hydroxamate 11d displayed subnanomolar potency (IC50: 0.5 nM) and selectivity up to 34000-fold over HDAC4 and from 100- to 1300-fold over all the other tested HDAC isoforms. The 2'-aminoanilides were class I-selective HDAC inhibitors, generally more potent against HDAC3, with the nicotinic anilide 12d being the most effective (IC50HDAC3 = 0.113 μM). When tested in U937 leukemia cells, the hydroxamates 9e, 11c, and 11d blocked over 80% cells in G2/M phase, whereas the anilides did not alter the cell cycle progress. In the same cell line, the hydroxamate 11c and the anilide 10b induced about 30% apoptosis, and the anilide 12c displayed about 40% cytodifferentiation. Finally, the most potent compounds in leukemia cells 9b, 11c, 10b, 10e, and 12c were also tested in K562, HCT116, and A549 cancer cells, displaying antiproliferative IC50 values at single-digit to sub-micromolar level
An update and ecological perspective on certain sentinel helminth endoparasites within the Mediterranean Sea
The Mediterranean Sea is recognized as a marine biodiversity hotspot. This enclosed basin is facing several anthropogenic-driven threats, such as seawater warming, pollution, overfishing, bycatch, intense maritime transport and invasion by alien species. The present review focuses on the diversity and ecology of specific marine trophically transmitted helminth endoparasites (TTHs) of the Mediterranean ecosystems, aiming to elucidate their potential effectiveness as ‘sentinels’ of anthropogenic disturbances in the marine environment. The chosen TTHs comprise cestodes and nematodes sharing complex life cycles, involving organisms from coastal and marine mid/upper-trophic levels as definitive hosts. Anthropogenic disturbances directly impacting the free-living stages of the parasites and their host population demographies can significantly alter the distribution, infection levels and intraspecific genetic variability of these TTHs. Estimating these parameters in TTHs can provide valuable information to assess the stability of marine trophic food webs. Changes in the distribution of particular TTHs species can also serve as indicators of sea temperature variations in the Mediterranean Sea, as well as the bioaccumulation of pollutants. The contribution of the chosen TTHs to monitor anthropogenic-driven changes in the Mediterranean Sea, using their measurable attributes at both spatial and temporal scales, is proposed.publishedVersio
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