1,693 research outputs found
Xenogeneic, extracorporeal liver perfusion in primates improves the ratio of branched-chain amino acids to aromatic amino acids (Fischer's ratio)
In fulminant hepatic failure (FHF), the development of hepatic encephalopathy is associated with grossly abnormal concentrations of plasma amino acids (PAA). Normalization of the ratio of branched-chain amino acids to aromatic amino acids (Fischer's ratio) correlates with clinical improvement. This study evaluated changes in PAA metabolism during 4 h of isolated, normothermic extracorporeal liver perfusion using a newly designed system containing human blood and a rhesus monkey liver. Bile and urea production were within the physiological range. Release of the transaminases AST, ALT and LDH were minimal. The ratio of branched (valine, leucine, isoleucine) to aromatic (tyrosine, phenylalanine) amino acids increased significantly. These results indicate that a xenogeneic extracorporeal liver perfusion system is capable of significantly increasing Fischer's ratio and may play a role in treating and bridging patients in FHF in the future
Ultrafast dynamics in unaligned MWCNTs decorated with metal nanoparticles
The relaxation dynamics of unaligned multi-walled carbon nanotubes decorated with metallic nanoparticles have been studied by using transient optical measurements. The fast dynamics due to the short-lived free-charge carriers excited by the pump are not affected by the presence of nanoparticles. Conversely, a second long dynamics, absent in bare carbon nanotubes, appears only in the decorated samples. A combination of experiment and theory allows us to ascribe this long dynamics to relaxation channels involving electronic states localized at the tube-nanoparticle interface
Generic Fibrational Induction
This paper provides an induction rule that can be used to prove properties of
data structures whose types are inductive, i.e., are carriers of initial
algebras of functors. Our results are semantic in nature and are inspired by
Hermida and Jacobs' elegant algebraic formulation of induction for polynomial
data types. Our contribution is to derive, under slightly different
assumptions, a sound induction rule that is generic over all inductive types,
polynomial or not. Our induction rule is generic over the kinds of properties
to be proved as well: like Hermida and Jacobs, we work in a general fibrational
setting and so can accommodate very general notions of properties on inductive
types rather than just those of a particular syntactic form. We establish the
soundness of our generic induction rule by reducing induction to iteration. We
then show how our generic induction rule can be instantiated to give induction
rules for the data types of rose trees, finite hereditary sets, and
hyperfunctions. The first of these lies outside the scope of Hermida and
Jacobs' work because it is not polynomial, and as far as we are aware, no
induction rules have been known to exist for the second and third in a general
fibrational framework. Our instantiation for hyperfunctions underscores the
value of working in the general fibrational setting since this data type cannot
be interpreted as a set.Comment: For Special Issue from CSL 201
Diffusion approximation for equilibrium Kawasaki dynamics in continuum
A Kawasaki dynamics in continuum is a dynamics of an infinite system of
interacting particles in which randomly hop over the space. In
this paper, we deal with an equilibrium Kawasaki dynamics which has a Gibbs
measure as invariant measure. We study a diffusive limit of such a
dynamics, derived through a scaling of both the jump rate and time. Under weak
assumptions on the potential of pair interaction, , (in particular,
admitting a singularity of at zero), we prove that, on a set of smooth
local functions, the generator of the scaled dynamics converges to the
generator of the gradient stochastic dynamics. If the set on which the
generators converge is a core for the diffusion generator, the latter result
implies the weak convergence of finite-dimensional distributions of the
corresponding equilibrium processes. In particular, if the potential is
from and sufficiently quickly converges to zero
at infinity, we conclude the convergence of the processes from a result in
[Choi {\it et al.}, J. Math. Phys. 39 (1998) 6509--6536]
Correlation of cognitive status, MRI- and SPECT-imaging in CADASIL patients
Although there is evidence for correlations between disability and magnetic resonance imaging (MRI) total lesion volume in autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), the significance of structural MRI abnormalities for cognitive dysfunction remains controversial. We performed detailed neuropsychological testing, high resolution MRI, and Tc-99m-ethyl cysteinate-dimer SPECT in three CADASIL patients. MR-images were rated independently by two investigators for the presence of white matter lesions, lacunar infarcts, microbleeds, and ventricular enlargement. Cortical atrophy was quantified by the use of automatic morphometric assessment of the cortical thickness. In addition, laboratory and patients' history data were collected in order to assess the individual vascular risk factor profile. The differences in cognitive performance between the three patients are neither explained by structural-, or functional neuroimaging, nor by the patient-specific vascular risk factor profiles. The neuroradiologically least affected patient met criteria for dementia, whereas the most severely affected patient was in the best clinical and cognitive state. Conventional structural and functional neuroimaging is important for the diagnosis of CADASIL, but it is no sufficient surrogate marker for the associated cognitive decline. Detailed neuropsychological assessment seems to be more useful, particularly with respect to the implementation of reliable outcome parameters in possible therapeutic trials
Waste prevention and education in five european countries
Artigo desenvolvido no âmbito de uma Unidade Curricular que funcionou em rede entre várias Universidades Europeias. Este artigo foi desenvolvido num trabalho em rede desenvolvido entre estudantes de diversas universidade e que avaliaram a implementação da diretiva quadro de resíduos em diversos países da União Europeia e apresentarem um conjunto de recomendações para se uniformizar e melhorar a gestão de resíduos na Europa com a aplicação da hierarquia dos resíduos.This research assessed the different goals of the EU Waste Framework Directive (2008) concerning waste prevention in five countries of the EU. The countries under research are the home countries of the EVS group members: Austria, Belgium, Germany, Netherlands and Portugal. The research about the status quo of waste prevention revealed that waste preven-tion has not reached yet. All the countries have high recycling rates and low dumping rate, ex-cept Portugal. Although decoupling trends start to appear and the countries are climbing up the waste hierarchy, waste prevention is still a mountain too far. The EVS group also checked if education was included in the waste prevention programmes and education plays a very im-portant role. The group looked for good examples of waste prevention and analyzed them with SWOT. The examples are a success in the home countries and can be implemented in other EU or even worldwide countries.info:eu-repo/semantics/publishedVersio
Constructing solutions to the Bj\"orling problem for isothermic surfaces by structure preserving discretization
In this article, we study an analog of the Bj\"orling problem for isothermic
surfaces (that are more general than minimal surfaces): given a real analytic
curve in , and two analytic non-vanishing orthogonal
vector fields and along , find an isothermic surface that is
tangent to and that has and as principal directions of
curvature. We prove that solutions to that problem can be obtained by
constructing a family of discrete isothermic surfaces (in the sense of Bobenko
and Pinkall) from data that is sampled along , and passing to the limit
of vanishing mesh size. The proof relies on a rephrasing of the
Gauss-Codazzi-system as analytic Cauchy problem and an in-depth-analysis of its
discretization which is induced from the geometry of discrete isothermic
surfaces. The discrete-to-continuous limit is carried out for the Christoffel
and the Darboux transformations as well.Comment: 29 pages, some figure
ИССЛЕДОВАНИЕ ВОЗДЕЙСТВИЯ АПОЛЯРНЫХ РЕАГЕНТОВ НА ТЕКУЧЕСТЬ ВОДОУГОЛЬНЫХ СУСПЕНЗИЙ
В последнее
время возник интерес к поведению водоугольных суспензий в связи с поиском
альтернативных видов энергоресурсов [1-4]. Повышенный интерес к водо
угольному топливу вызван ростом цен на нефть и нефтепродукты и ограниченностью запасов этого сырья. Водоугольные смеси широко изучаются в различных странах мира, так как они могут заменить и традиционное пылевидное топливо, перед которым имеют ряд существенных преимуществ. Особенности горения водоугольного топлива позволяют относить его к разряду экологически
чистых видов топлива. При сжигании угля в виде водоугольной суспензии увеличивается скорость выгорания углерода, снижаются выбросы вредных веществ в атмосферу и образование оксидов азота
- …