Non rectification of heat in graded Si-Ge alloys

We investigate the possibility to obtain a thermal diode with functionally graded Si-Ge alloys. A wire with variable section is considered. After the introduction of a formula giving the thermal conductivity of the wire as a function of the species content and of the diameter of the wire, numerical and analytical results are presented supporting the impracticability to get a thermal diode with the characteristics here considered. However, the present study opens the way to further generalisations amenable to give applicative promising results.Comment: 9 pages, 3 figures, conference pape

Pathophysiology of Post Transplant Hypertension in Kidney Transplant: Focus on Calcineurin Inhibitors Induced Oxidative Stress and Renal Sodium Retention and Implications with RhoA/Rho Kinase Pathway.

Post-transplant hypertension is a common occurrence during treatment with calcineurin inhibitors (CNIs) in kidney transplant population. The pathogenesis of vasoconstriction induced by CNIs involves vascular tone alterations and kidney sodium transport regulation. Among the factors involved a key role is played by the activation of intrarenal renin-angiotensin system with enhanced release of Angiotensin II (Ang II) and increase of oxidative stress. A common pathway between oxidative stress and hypertension induced by CNIs may be identified in the involvement of the activation of RhoA/Rho kinase pathway, key for the induction of hypertension and cardiovascular-renal remodeling, of the oxidative stress mediated increased nitric oxide (NO) metabolism and increased renal sodium retention via increased activity of thiazide-sensitive sodium chloride cotransporter (NCC) in the distal tubule. We examined literature data including those coming from our group regarding the role of oxidative stress and sodium retention in CNIs induced hypertension and their involvement in cardiovascular-renal remodeling. Based on the available data, we have provided support to the activation of RhoA/Rho kinase pathway as an important effector in the pathophysiology of CNIs induced post-transplant hypertension via activation of oxidative stress and sodium retention. Clarification of how the biochemical and molecular mechanisms that regulate the processes involved in CNIs induced post transplant hypertension work and interact, would provide further insights not only into the comprehension of the pathophysiology of CNIs induced post transplant hypertension but could also have a positive impact on the clinical ground through the identification of significant targets. Their specific pharmacologic targeting might have multiple beneficial effects on the whole cardiovascular-renal function. The demonstration that in kidney transplanted patients with CNIs induced post-transplanted hypertension, the treatment of hypertension with different antihypertensive drugs inducing a comparable blood pressure reduction but different effects for example on oxidative stress and oxidative stress related proteins and/or Rho kinase and sodium retention, could be helpful for the choice of the antihypertensive treatment in these patients which takes advantage from effects of these drugs beyond blood pressure reduction

Excess TPX2 Interferes with Microtubule Disassembly and Nuclei Reformation at Mitotic Exit.

The microtubule-associated protein TPX2 is a key mitotic regulator that contributes through distinct pathways to spindle assembly. A well-characterised function of TPX2 is the activation, stabilisation and spindle localisation of the Aurora-A kinase. High levels of TPX2 are reported in tumours and the effects of its overexpression have been investigated in cancer cell lines, while little is known in non-transformed cells. Here we studied TPX2 overexpression in hTERT RPE-1 cells, using either the full length TPX2 or a truncated form unable to bind Aurora-A, to identify effects that are dependent-or independent-on its interaction with the kinase. We observe significant defects in mitotic spindle assembly and progression through mitosis that are more severe when overexpressed TPX2 is able to interact with Aurora-A. Furthermore, we describe a peculiar, and Aurora-A-interaction-independent, phenotype in telophase cells, with aberrantly stable microtubules interfering with nuclear reconstitution and the assembly of a continuous lamin B1 network, resulting in daughter cells displaying doughnut-shaped nuclei. Our results using non-transformed cells thus reveal a previously uncharacterised consequence of abnormally high TPX2 levels on the correct microtubule cytoskeleton remodelling and G1 nuclei reformation, at the mitosis-to-interphase transition

In vitro experiments and infrared spectroscopy analysis of acid and alkaline phosphatase inhibition by vanadium complexes

In the course of our research of vanadium-containing complexes, two oxidovanadium complexes containing vanadium(V) and (IV) core with 4-aminobenzoic acid and/or peroxo anion as ligands were synthesized and characterized by elemental analysis, conductivity measurements, thermogravimetric analysis, and spectroscopies.(([VO(O 2 )(C 7 H 6 NO 2 )(H 2 O)] . H 2 O, [VO(C 7 H 6 NO 2 ) 2 H 2 O]) were supported by experimental data and theoretical studies (Density functional theory, DFT). The complexes were evaluated in vitro as phosphatase inhibitors (alkaline and acid enzymes) being considered as potential pharmaceutical agents under over-expression of those biochemical markers.The effect achieved was then analysed through FTIR spectroscopy. Changes in the finger print substrate bands as well as induced conformational changes on phosphatases enzymes secondary structure were further examined. Eventually albumin interactions experimentswere performed in order to derive their bioavailability.Fil: Parente, Juliana Elena. 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: Naso, Luciana Gissella. 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: Jori, Khalil. Universidad Nacional de La Plata; ArgentinaFil: Franca, Carlos Alberto. 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: da Costa Ferreira, Ana Maria. Universidade de Sao Paulo; BrasilFil: Williams, Patricia Ana María. 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: Ferrer, Evelina Gloria. 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"; Argentin

Sistemas modelos biomiméticos de haloperoxidasas e inhibidores de fosfatasa ácida y alcalina

El objetivo de esta investigación se centra en el estudio de las potencialidades de los complejos de coordinación con vanadio como simuladores de la actividad desarrollada por las enzimas peroxidasas e inhibidores de la actividad de las fosfatasas

MiR-211 is essential for adult cone photoreceptor maintenance and visual function.

MicroRNAs (miRNAs) are key post-transcriptional regulators of gene expression that play an important role in the control of fundamental biological processes in both physiological and pathological conditions. Their function in retinal cells is just beginning to be elucidated, and a few have been found to play a role in photoreceptor maintenance and function. MiR-211 is one of the most abundant miRNAs in the developing and adult eye. However, its role in controlling vertebrate visual system development, maintenance and function so far remain incompletely unexplored. Here, by targeted inactivation in a mouse model, we identify a critical role of miR-211 in cone photoreceptor function and survival. MiR-211 knockout (-/-) mice exhibited a progressive cone dystrophy accompanied by significant alterations in visual function. Transcriptome analysis of the retina from miR-211-/- mice during cone degeneration revealed significant alteration of pathways related to cell metabolism. Collectively, this study highlights for the first time the impact of miR-211 function in the retina and significantly contributes to unravelling the role of specific miRNAs in cone photoreceptor function and survival

In vitro experiments and infrared spectroscopy analysis of acid and alkaline phosphatase inhibition by vanadium complexes

In the course of our research on vanadium-containing complexes, two oxidovanadium complexes containing vanadium(V) and (IV) cores with 4-aminobenzoic acid and/or the peroxo anion as ligands were synthesized and characterized by elemental analysis, conductivity measurements, thermogravimetric analysis, and 1H NMR, EPR, FTIR, and UV/vis spectroscopies. Their compositions and geometrical structures ([VO(O2)(C7H6NO2)(H2O)]·H2O and [VO(C7H6NO2)2H2O]) were supported by experimental data and theoretical studies (density functional theory, DFT). The complexes were evaluated in vitro as phosphatase inhibitors (alkaline and acid enzymes), being considered as potential pharmaceutical agents under over-expression of those biochemical markers. The effect achieved was then analysed through FTIR spectroscopy. Changes in the fingerprint substrate bands as well as induced conformational changes in phosphatase enzymes’ secondary structure were further examined. Eventually albumin interaction experiments were performed in order to derive their bioavailability.Centro de Química Inorgánic

Versatility in the biological behavior of two aminobenzoate oxidovanadium (V, IV) compounds. Inhibition or simulation of enzymes

The pharmacological potential of vanadium compounds is of great interest to researchers in treatments of various diseases (diabetes, cancer, tropical endemic diseases, etc.). On the basis of the potential biological/pharmacological applications, in this work we have synthesized and physico-chemically characterized, two new complexes containing vanadium (IV) and (V) with 4-aminobenzoic acid as the ligand (L)

Uniform attractors for a semilinear evolution problem in hereditary simple fluids

This paper is devoted to study the asymptotic behavior, as time tends to infinity, of the solutions of a semilinear partial differential equation of hyperbolic type with a convolution term describing simple fluids with fading memory. The past history of the displacement is regarded itself as a new variable, so that the corresponding initial boundary value problem is transformed into a dynamical system in a history space setting. Under proper assumptions on the nonlinear term, the existence of an uniform absorbing set and an universal attractor in suitable function spaces are achieved

On the exponential stability of electromagnetic systems with memory

Some linear evolution problems arising in the theory of hereditary electromagnetism are considered here. Making use of semigroup techniques, well-posedness results are discussed, as well as asymptotic behavior of solutions, for rigid conductors with electrical memory