2,145 research outputs found
Dynamics in Several Complex Variables
In this chapter we shall describe the dynamics of holomorphic self-maps of taut manifolds, and in particular the dynamics of holomorphic self-maps of convex and strongly pseudoconvex domains. A main tool in this exploration will be provided by the Kobayashi distance
An Algorithmic Test for Diagonalizability of Finite-Dimensional PT-Invariant Systems
A non-Hermitean operator does not necessarily have a complete set of
eigenstates, contrary to a Hermitean one. An algorithm is presented which
allows one to decide whether the eigenstates of a given PT-invariant operator
on a finite-dimensional space are complete or not. In other words, the
algorithm checks whether a given PT-symmetric matrix is diagonalizable. The
procedure neither requires to calculate any single eigenvalue nor any numerical
approximation.Comment: 13 pages, 1 figur
σ2 receptor and its role in cancer with focus on a multitarget directed ligand (Mtdl) approach
Sigma-2 (σ2) is an endoplasmic receptor identified as the Endoplasmic Reticulum (ER) transmembrane protein TMEM97. Despite its controversial identity, which was only recently solved, this protein has gained scientific interest because of its role in the proliferative status of cells; many tumor cells from different organs overexpress the σ2 receptor, and many σ2 ligands display cytotoxic actions in (resistant) cancer cells. These properties have shed light on the σ2 receptor as a potential druggable target to be bound/activated for the diagnosis or therapy of tumors. Additionally, diverse groups have shown how the σ2 receptor can be exploited for the targeted delivery of the anticancer drugs to tumors. As the cancer disease is a multifactorial pathology with multiple cell populations, a polypharmacological approach is very often needed. Instead of the simultaneous administration of different classes of drugs, the use of one molecule that interacts with diverse pharmacological targets, namely MultiTarget Directed Ligand (MTDL), is a promising and currently pursued strategy, that may overcome the pharmacokinetic problems associated with the administration of multiple molecules. This review aims to point out the progress regarding the σ2 ligands in the oncology field, with a focus on MTDLs directed towards σ2 receptors as promising weapons against (resistant) cancer diseases
Insulin Resistance and Body Fat Distribution in South Asian Men Compared to Caucasian Men
South Asians are susceptible to insulin resistance even without obesity. We examined the characteristics of body fat content, distribution and function in South Asian men and their relationships to insulin resistance compared to Caucasians.Twenty-nine South Asian and 18 Caucasian non-diabetic men (age 27+/-3 and 27+/-3 years, respectively) underwent euglycemic-hyperinsulinemic clamp for insulin sensitivity, underwater weighing for total body fat, MRI of entire abdomen for intraperitoneal (IP) and subcutaneous abdominal (SA) fat and biopsy of SA fat for adipocyte size.Compared to Caucasians, in spite of similar BMI, South Asians had higher total body fat (22+/-6 and 15+/-4% of body weight; p-value<0.0001), higher SA fat (3.5+/-1.9 and 2.2+/-1.3 kg, respectively; p-value = 0.004), but no differences in IP fat (1.0+/-0.5 and 1.0+/-0.7 kg, respectively; p-value = 0.4). SA adipocyte cell size was significantly higher in South Asians (3491+/-1393 and 1648+/-864 microm2; p-value = 0.0001) and was inversely correlated with both glucose disposal rate (r-value = -0.57; p-value = 0.0008) and plasma adiponectin concentrations (r-value = -0.71; p-value<0.0001). Adipocyte size differences persisted even when SA was matched between South Asians and Caucasians.Insulin resistance in young South Asian men can be observed even without increase in IP fat mass and is related to large SA adipocytes size. Hence ethnic excess in insulin resistance in South Asians appears to be related more to excess truncal fat and dysfunctional adipose tissue than to excess visceral fat
Screen-Printed Biosensors for the Early Detection of Biomarkers Related to Alzheimer Disease: Preliminary Results
Abstract Alzheimer disease (AD), despite representing the most common type of dementia in elderly, is still lacking reliable methodologies for early diagnosis. A potential biomarker associated to AD development has been recently identified in the open isoform of p53, redox sensitive protein, currently quantified using a specific blood-based enzyme-linked immunosorbent assay (ELISA). In order to overcome ELISA limitations (level of detection, standardization and reliability), this study aimed to realize a low cost highly sensitive portable point-of-care (PoC) testing system based on screen printed electrochemical sensors (SPES). The study specifically reported the design of the platform, including the sensing probe and the electronic circuit devoted to the conditioning of the electric signal. Preliminary results were obtained from circuit testing by using controlled concentrations of electrolytic solutions and from an initial calibration stage by using Anodic Stripping Voltammetry (ASV) measurements. Future works will address the quantification of unknown concentration of unfolded p53 in peripheral blood samples, thus to validate the here-presented low cost, easy to use and highly precise platform
The impact of correlated projections on weak lensing cluster counts
Large-scale structure projections are an obstacle in converting the shear
signal of clusters detected in weak-lensing maps into virial masses. However,
this step is not necessary for constraining cosmology with the shear-peak
abundance, if we are able to predict its amplitude. We generate a large
ensemble of N-body simulations spanning four cosmological models, with total
volume V~1 (Gpc/h)^3 per model. Variations to the matter density parameter and
amplitude of fluctuations are considered. We measure the abundance of peaks in
the mass density projected in ~100 Mpc/h slabs to determine the impact of
structures spatially correlated with the simulation clusters, identified by the
3D friends-of-friends algorithm. The halo model shows that the choice of the
smoothing filter for the density field is important in reducing the
contribution of correlated projections to individual halo masses. Such
contributions are less than 2% in the case of the optimal, compensated filter
used throughout this analysis. We measure the change in the mass of peaks when
projected in slabs of various thicknesses. Peaks in slabs of 26 Mpc/h and 102
Mpc/h suffer an average mass change of less than 2% compared to their mass in
slabs of 51 Mpc/h. We then explore the cosmology dependence of the
projected-peak mass function, and find that, for a wide range of slab
thicknesses (<500 Mpc/h), it scales with cosmology in exactly the same way as
the 3D friends-of-friends mass function and the Sheth-Tormen formula. This
extends the earlier result of Marian et al. (2009). Finally, we show that for
all cosmological models considered, the low and intermediate mass bins of the
peak abundance can be described using a modified Sheth-Tormen functional form
to within 10%-20% accuracy.Comment: 19 pages, 14 figures, accepted for publication in the Astrophysical
Journa
Abstract basins of attraction
Abstract basins appear naturally in different areas of several complex
variables. In this survey we want to describe three different topics in which
they play an important role, leading to interesting open problems
A symmetrical dirhenium(I) complex with 4,4''-azobis(2,2'-bipyridine) as a bridging ligand: Synthesis, physicochemical properties and applications in detection of biologically relevant thiols and in chemotherapy for bone cancer
A new dinuclear complex of formula [{Re(CO)3(py)}2(μ-4,4”-azobpy)](PF6)2, with py = pyridine and 4,4”-azobpy = 4,4”-azobis(2,2'-bipyridine), has been synthesized and characterized by spectroscopic and electrochemical techniques. The symmetrical nature of the dimetallic cation has been confirmed by nuclear magnetic resonance (NMR) measurements. When adding L-cysteine or L-glutathione, large and rapid changes in its UV-Vis absorption spectra were observed, which can be used for detecting both biologically relevant thiols. A promising activity for using this complex as a chemotherapeutic agent for bone cancer was also disclosed. Quantum mechanical calculations supported the experimental data.Fil: Abate, Pedro Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; ArgentinaFil: Sottile, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: León, Ignacio E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Vergara, Mónica M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; ArgentinaFil: Katz, Néstor Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; Argentin
Transition probabilities for general birth-death processes with applications in ecology, genetics, and evolution
A birth-death process is a continuous-time Markov chain that counts the
number of particles in a system over time. In the general process with
current particles, a new particle is born with instantaneous rate
and a particle dies with instantaneous rate . Currently no robust and
efficient method exists to evaluate the finite-time transition probabilities in
a general birth-death process with arbitrary birth and death rates. In this
paper, we first revisit the theory of continued fractions to obtain expressions
for the Laplace transforms of these transition probabilities and make explicit
an important derivation connecting transition probabilities and continued
fractions. We then develop an efficient algorithm for computing these
probabilities that analyzes the error associated with approximations in the
method. We demonstrate that this error-controlled method agrees with known
solutions and outperforms previous approaches to computing these probabilities.
Finally, we apply our novel method to several important problems in ecology,
evolution, and genetics
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