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Search Results: 1 - 10 of 1777 matches for " Ewa Lewin "
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Epigenetic Methylation of Parathyroid CaR and VDR Promoters in Experimental Secondary Hyperparathyroidism
Jacob Hofman-Bang,Eva Gravesen,Klaus Olgaard,Ewa Lewin
International Journal of Nephrology , 2012, DOI: 10.1155/2012/123576
Abstract: Secondary hyperparathyroidism (s-HPT) in uremia is characterized by decreased expression in the parathyroids of calcium sensing (CaR) and vitamin D receptors (VDR). Parathyroid hormone (PTH) is normalized despite low levels of CaR and VDR after experimental reversal of uremia. The expression of CaR in parathyroid cultures decreases rapidly. Methylation of promoter regions is often detected during epigenetic downregulation of gene expression. Therefore, using an experimental rat model, we examined changes in methylation levels of parathyroid CaR and VDR promoters in vivo and in vitro. Methods. Uremia was induced by 5/6 nephrectomy. Melting temperature profiling of CaR and VDR PCR products after bisulfite treatment of genomic DNA from rat parathyroids was performed. Real-time PCR measured expression of PTH, CaR, VDR, and klotho genes in vitro. Results. Parathyroids from uremic rats had similar low levels of methylation in vivo and in vitro. In culture, a significant downregulation of CaR, VDR, and klotho within two hours of incubation was observed, while housekeeping genes remained stable for 24 hours. Conclusion. In uremic s-HPT and in vitro, no overall changes in methylation levels in the promoter regions of parathyroid CaR and VDR genes were found. Thus, epigenetic methylation of these promoters does not explain decreased parathyroid expression of CaR and VDR genes in uremic s-HPT. 1. Introduction Secondary hyperparathyroidism in uremia (s-HPT)—a disorder caused by progressive loss of kidney function, low levels of active vitamin D (1,25(OH)2D (calcitriol)), increased phosphate retention, and low levels of plasma ionized calcium (Ca2+) [1, 2]—results in the highly elevated synthesis and secretion of parathyroid hormone (PTH) and enlargement of the parathyroid glands in order to maintain normal plasma Ca2+ and phosphate levels. The calcium-sensing receptor (CaR) plays a key role in maintaining of Ca2+ concentrations in extracellular fluids within a narrow range, primarily by modulating the function of the parathyroid glands. The CaR belongs to family C of the superfamily of seven transmembrane G-protein-coupled receptors. It regulates the biosynthesis and secretion of parathyroid hormone (PTH), as well as parathyroid cell proliferation, which is inhibited at high Ca2+ concentrations and stimulated at low Ca2+ concentrations. The effect of low calcium on PTH gene expression is posttranscriptional. Another important regulator of the PTH gene, calcitriol, decreases PTH gene expression at the transcriptional level. Calcitriol’s action is mediated via
Constructive Patriotism in Wartime  [PDF]
Eyal Lewin
Open Journal of Political Science (OJPS) , 2013, DOI: 10.4236/ojps.2013.34015
Abstract:

As opposed to blind patriotism, a moderate form of constructive patriotism has been depicted in previous research and empirically observed. The major distinction between blind patriotism and constructive patriotism lies in the latter’s capacity for criticism. Our research suggests, however, an additional distinction dividing constructive patriotism into two forms: one form is capable of practical judgment (hence, political constructive patriotism), and the other form is critical on grounds of ethical issues (hence moral constructive patriotism). This study then seeks to examine which sort of patriotism prevails within society during wartime; of special interest, for that matter, are the suggested variations of constructive patriotism. Two diverse cases have been chosen in order to examine the reactions within a democratic society: The American case of the 2003 invasion of Iraq and the Israeli case of the 2006 war in Lebanon. A substantive content analysis has been employed, surveying social processes through a variety of articles in an American and an Israeli daily newspaper. The findings reveal that in both cases among expressions of constructive patriotism, those of political constructive patriotism form a vast majority and only a few of them express moral constructive patriotism. It therefore seems that constructive patriots are not necessarily as moral as they might seem to be at first glance, even though they criticize state and society. The case of war in particular proves how on moral grounds criticism is important, but not enough.

Wp yw urodzeniowej masy cia a na dojrzewanie p ciowe 14-letnich dzieci
Marzena Nordyńska-Sobczak,Ewa Ma?ecka-Tendera,Katarzyna Klimek,Joanna Lewin-Kowalik
Pediatric Endocrinology, Diabetes and Metabolism , 2000,
Abstract: Zaburzenia wzrastania wyst puj ce w yciu p odowym mog mie swoje implikacje w pó niejszym okresie ycia. Celem pracy by o zbadanie wp ywu urodzeniowej masy cia a na wzrost i wska nik masy cia a oraz stopień zaawansowania dojrzewania p ciowego u 14-letnich dzieci. Badania przeprowadzono u 437 dzieci (230 dziewczynek i 207 ch opców) w wieku 14,2 1,1 r. Dane o wzro cie rodziców, 1. miesi czce matki oraz warunkach socjalno-ekonomicznych rodziny uzyskano na podstawie ankietyzacji rodziców. Stwierdzono istotn korelacj urodzeniowej masy cia a ze wzrostem 14-letnich dzieci, natomiast nie zaobserwowano jej wp ywu na ich wska nik masy cia a. Wiek 1. miesi czki dziewcz t zale a wy cznie od wieku menarche matki, nie by natomiast uwarunkowany urodzeniow mas cia a i czynnikami socjalno-ekonomicznymi. U dziewcz t o ma ej masie urodzeniowej, w odró nieniu od dziewcz t o masie urodzeniowej wi kszej ni 2500 g, nie wyst powa a jednak akceleracja wieku osi gni cia menarche. Stopień zaawansowania dojrzewania p ciowego nie ró ni si istotnie w grupach o ma ej, prawid owej i du ej urodzeniowej masie cia a. Wyniki przeprowadzonych badań wskazuj , e urodzeniow masa cia a mo e znamiennie wp ywa na wzrost w okresie dojrzewania, nie maj c znaczenia dla masy cia a i nie zmieniaj c istotnie samego procesu po-kwitania.
Dynamika wzrastania w pierwszych 6 latach ycia w zale no ci od urodzeniowej masy cia a
Ewa Ma?ecka-Tendera,Marzena Nordyńska-Sobczak,Katarzyna Klimek,Joanna Lewin-Kowalik
Pediatric Endocrinology, Diabetes and Metabolism , 2000,
Abstract: Celem pracy by o zbadanie dynamiki przyrostu masy i wysoko ci cia a u dziewczynek i ch opców w pierwszych 6 latach ycia oraz stwierdzenie, wjakim stopniu i w którym przedziale wieku urodzeniowa masa cia a (u.m.c.) mo e j modyfikowa . Badania przeprowadzono u 437 dzieci (230 dziewczynek i 207 ch opców), okre laj c ich dynamik wzrastania mi dzy urodzeniem a 2, 4 i 6 r. . w zale no ci od u.m.c. wi kszej od 2500 g, w przedziale 2501-3500 g i wi kszej od 3500 g. Stwierdzono, e dziewczynki o najmniejszej u.m.c. wykazywa y najwi kszy przyrost masy cia a w okresie mi dzy urodzeniem a 2 r. ., a najwi ksza dynamika przyrostu wysoko ci cia a wyst powa a u nich w okresie mi dzy 2 a 4 r. . U ch opców nie znaleziono ró nic w dynamice przyrostu masy cia a dla 3 przedzia ów masy urodzeniowej. Ch opcy o najmniejszej urodze-niowej masie cia a najwi ksz dynamik wzrostu wykazywali, podobnie jak dziewczynki, mi dzy 2 a 4 r. . Wysokie tempo wzrastania mi dzy 2 a 4 r. ., jakie obserwowano u dzieci z ma u.m.c., mo e wi c korzystnie modyfikowa ich niedobór wzrostu, wyst puj cy we wcze niejszym okresie ycia.
Geometric methods for nonlinear many-body quantum systems
Mathieu Lewin
Physics , 2010, DOI: 10.1016/j.jfa.2010.11.017
Abstract: Geometric techniques have played an important role in the seventies, for the study of the spectrum of many-body Schr\"odinger operators. In this paper we provide a formalism which also allows to study nonlinear systems. We start by defining a weak topology on many-body states, which appropriately describes the physical behavior of the system in the case of lack of compactness, that is when some particles are lost at infinity. We provide several important properties of this topology and use them to provide a simple proof of the famous HVZ theorem in the repulsive case. In a second step we recall the method of geometric localization in Fock space as proposed by Derezi\'nski and G\'erard, and we relate this tool to our weak topology. We then provide several applications. We start by studying the so-called finite-rank approximation which consists in imposing that the many-body wavefunction can be expanded using finitely many one-body functions. We thereby emphasize geometric properties of Hartree-Fock states and prove nonlinear versions of the HVZ theorem, in the spirit of works of Friesecke. In the last section we study translation-invariant many-body systems comprising a nonlinear term, which effectively describes the interactions with a second system. As an example, we prove the existence of the multi-polaron in the Pekar-Tomasevich approximation, for certain values of the coupling constant.
Renormalization of Dirac's Polarized Vacuum
Mathieu Lewin
Physics , 2010,
Abstract: We review recent results on a mean-field model for relativistic electrons in atoms and molecules, which allows to describe at the same time the self-consistent behavior of the polarized Dirac sea. We quickly derive this model from Quantum Electrodynamics and state the existence of solutions, imposing an ultraviolet cut-off $\Lambda$. We then discuss the limit $\Lambda\to\infty$ in detail, by resorting to charge renormalization.
A nonlinear variational problem in relativistic quantum mechanics
Mathieu Lewin
Physics , 2012,
Abstract: We describe several recent results obtained in collaboration with P. Gravejat, C. Hainzl, E. S\'er\'e and J.P. Solovej, concerning a nonlinear model for the relativistic quantum vacuum in interaction with a classical electromagnetic field.
Mean-field limit of Bose systems: rigorous results
Mathieu Lewin
Physics , 2015,
Abstract: We review recent results about the derivation of the Gross-Pitaevskii equation and of the Bogoliubov excitation spectrum, starting from many-body quantum mechanics. We focus on the mean-field regime, where the interaction is multiplied by a coupling constant of order 1/N where N is the number of particles in the system.
Comment on `Solutions to quasi-relativistic multi-configurative Hartree-Fock equations in quantum chemistry', by C. Argaez & M. Melgaard
Mathieu Lewin
Mathematics , 2011,
Abstract: In a recent paper published in Nonlinear Analysis: Theory, Methods & Applications, C. Argaez and M. Melgaard studied excited states for pseudo-relativistic multi-configuration methods. Their paper follows a previous work of mine in the non-relativistic case (Arch. Rat. Mech. Anal., 171, 2004). The main results of the paper of C. Argaez and M. Melgaard are correct, but the proofs are both wrong and incomplete.
ALICE as a tool for programming at schools  [PDF]
Ewa Graczyńska
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.22021
Abstract: We present some possible application of ALICE in the context of a possible attraction of pupils (especially girls) in early programming course. Our examples presented in the paper are fully explained on the base of [1].
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