256 research outputs found
Optimal Placement of Water Quality Monitoring Stations in Sewer Systems: An Information Theory Approach
A core problem associated with the water quality monitoring in the sewer system is the optimal placement of a limited number of
monitoring sites. A methodology is provided for optimally design water quality monitoring stations in sewer networks. The
methodology is based on information theory, formulated as a multi-objective optimization problem and solved using NSGA-II.
Computer code is written to estimate two entropy quantities, namely Joint Entropy, a measure of information content, and Total
Correlation, a measure of redundancy, which are maximized and minimized, respectively. The test on a real sewer network
suggests the effectiveness of the proposed methodology
Tubulin nitration in human gliomas
Immunohistochem. and biochem. investigations showed that significant protein nitration occurs in human gliomas, esp. in grade IV glioblastomas at the level of astrocytes and oligodendrocytes and neurons. Enhanced alpha-tubulin immunoreactivity was co-present in the same elements in the glioblastomas. Proteomic methodologies were employed to identify a nitrated protein band at 55 kDa as alpha-tubulin. Peptide mass fingerprinting procedures demonstrated that tubulin is nitrated at Tyr224 in grade IV tumor samples but is unmodified in grade I samples and in non-cancerous brain tissue. These results provide the first characterization of endogenously nitrated tubulin from human tumor samples
Exponential instability in the fractional Calder\'on problem
In this note we prove the exponential instability of the fractional
Calder\'on problem and thus prove the optimality of the logarithmic stability
estimate from \cite{RS17}. In order to infer this result, we follow the
strategy introduced by Mandache in \cite{M01} for the standard Calder\'on
problem. Here we exploit a close relation between the fractional Calder\'on
problem and the classical Poisson operator. Moreover, using the construction of
a suitable orthonormal basis, we also prove (almost) optimality of the Runge
approximation result for the fractional Laplacian, which was derived in
\cite{RS17}. Finally, in one dimension, we show a close relation between the
fractional Calder\'on problem and the truncated Hilbert transform.Comment: 17 page
Stability properties of an inverse parabolic problem with unknown boundaries
We treat the stability issue for an inverse problem arising from nondestructive evaluation by thermal imaging. We consider the determination of an unknown portion of the boundary of a thermic conducting body by overdetermined boundary data for a parabolic initial-boundary value problem.We obtain that when the unknown part of the boundary is a priori known to be smooth, the data are as regular as possible and all possible measurements are taken into account, the problem is exponentially ill-posed. Then, we prove that a single measurement with some a priori information on the unknown part of the boundary and minimal assumptions on the data, in particular on the thermal conductivity, is enough to have stable determination of the unknown boundary. Given the exponential illposedness, the stability estimate obtained is optimal
Exponential instability for inverse elliptic problems with unknown boundaries
We prove that the inverse problem of determining unknown defects of various types in a conductor by performing electrostatic measurements at the boundary is severely ill-posed. We show that the ill-posedness does not depend on the nature of the defects to be determined and, more importantly, by the kind, choice and number of measurements performed
Carleman estimate for second order elliptic equations with Lipschitz leading coefficients and jumps at an interface
Mutations in SYNGAP1 cause intellectual disability, autism, and a specific form of epilepsy by inducing haploinsufficiency
De novo mutations in SYNGAP1, which codes for a RAS/RAP GTP-activating protein, cause nonsyndromic intellectual disability (NSID). All disease-causing point mutations identified until now in SYNGAP1 are truncating, raising the possibility of an association between this type of mutations and NSID. Here, we report the identification of the first pathogenic missense mutations (c.1084T>C [p.W362R], c.1685C>T [p.P562L]) and three novel truncating mutations (c.283dupC [p.H95PfsX5], c.2212_2213del [p.S738X], and (c.2184del [p.N729TfsX31]) in SYNGAP1 in patients with NSID. A subset of these patients also showed ataxia, autism, and a specific form of generalized epilepsy that can be refractory to treatment. All of these mutations occurred de novo, except c.283dupC, which was inherited from a father who is a mosaic. Biolistic transfection of wild-type SYNGAP1 in pyramidal cells from cortical organotypic cultures significantly reduced activity-dependent phosphorylated extracellular signal-regulated kinase (pERK) levels. In contrast, constructs expressing p.W362R, p.P562L, or the previously described p.R579X had no significant effect on pERK levels. These experiments suggest that the de novo missense mutations, p.R579X, and possibly all the other truncating mutations in SYNGAP1 result in a loss of its function. Moreover, our study confirms the involvement of SYNGAP1 in autism while providing novel insight into the epileptic manifestations associated with its disruption.</p
Critical aspects in dissolution testing of nanomaterials in the oro-gastrointestinal tract: the relevance of juice composition for hazard identification and grouping
The dissolution of a nanomaterial (NM) in an in vitro simulant of the oro-gastrointestinal (OGI) tract is an important predictor of its biodurability in vivo. The cascade addition of simulated digestive juices (saliva, stomach and intestine), including inorganic/organic biomacromolecules and digestive enzymes (complete composition, referred to as “Type 1 formulation”), strives for realistic representation of chemical composition of the OGI tract. However, the data robustness requires consideration of analytical feasibility, such as the use of simplified media. Here we present a systematic analysis of the effects exerted by different digestive juice formulations on the dissolution% (or half-life values) of benchmark NMs (e.g., zinc oxide, titanium dioxide, barium sulfate, and silicon dioxide). The digestive juices were progressively simplified by removal of components such as organic molecules, enzymes, and inorganic molecules (Type 2, 3 and 4). The results indicate that the “Type 1 formulation” augments the dissolution via sequestration of ions by measurable factors compared to formulations without enzymes (i.e., Type 3 and 4). Type 1 formulation is thus regarded as a preferable option for predicting NM biodurability for hazard assessment. However, for grouping purposes, the relative similarity among diverse nanoforms (NFs) of a NM is decisive. Two similarity algorithms were applied, and additional case studies comprising NFs and non NFs of the same substance were included. The results support the grouping decision by simplified formulation (Type 3) as a robust method for screening and grouping purposes
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