Showing papers by "Romanian Academy published in 1998"
TL;DR: The objective of the present review is to provide evidence that the cell surface sialic acid serves as a determinant of the life-span and provide evidence for the existence of an alternative pathway that is independent of immunoglobulins.
362 citations
TL;DR: The data demonstrate that FcRn is expressed in functionally active form in endothelial cells, indicating that these cells are a possible site at which serum IgG homeostasis is maintained.
Abstract: Our recent data indicate that the MHC class I-related receptor, FcRn, plays a role in regulating serum IgG levels, in addition to its known role in transferring IgG from mother to young. In the current study, the distribution of FcRn in adult mice has been investigated using several approaches. First, tissue distribution of anti-FcRn F(ab')2, murine IgG1 and recombinant, IgG1-derived Fc-hinge fragments has been analyzed, and these FcRn binding proteins localize predominantly in skin and muscle with lesser amounts in liver and adipose tissue. Second, histochemical analyses of muscle and liver with anti-FcRn F(ab')2 indicate that FcRn is expressed in the endothelium of small arterioles and capillaries, but not in larger vessels such as the central vein and portal vasculature. Third, immunoprecipitation and immunofluorescence studies of cultured murine endothelial cells show that functional FcRn is expressed in these cells, and is located within vesicular structures in the cytosol and not on the membrane. Taken together the data demonstrate that FcRn is expressed in functionally active form in endothelial cells, indicating that these cells are a possible site at which serum IgG homeostasis is maintained.
264 citations
TL;DR: The immortalized HaCaT cells reveal a generally high competence to realize an epidermal phenotype in a natural environment and appear therefore qualified for in vitro studies on structural and regulatory aspects of keratinocyte physiology and pathology.
134 citations
TL;DR: In this paper, the stability of the Fredholm properties on interpolation scales of quasi-Banach spaces is investigated, motivated by problems arising in PDEs and several applications are presented.
Abstract: We investigate the stability of Fredholm properties on interpolation scales of quasi-Banach spaces. This analysis is motivated by problems arising in PDE’s and several applications are presented.
123 citations
TL;DR: Several types of sticker systems are shown to characterize (modulo a weak coding) the regular languages, hence the power of finite automata, and one variant is proven to be equivalent to Turing machines.
Abstract: We introduce the sticker systems, a computability model, which is an abstraction of the computations using the Watson-Crick complementarity as in Adleman's DNA computing experiment, [1]. Several types of sticker systems are shown to characterize (modulo a weak coding) the regular languages, hence the power of finite automata. One variant is proven to be equivalent to Turing machines. Another one is found to have a strictly intermediate power.
110 citations
01 Jan 1998
TL;DR: From silicon to carbon, from microchips to DNA molecules, the basic idea in DNA computing is to use information processing capabilities of organic molecules in computers to replace digital switching primitives as discussed by the authors.
Abstract: From silicon to carbon. From microchips to DNA molecules. This is the basic idea in DNA computing. Information-processing capabilities of organic molecules can be used in computers to replace digital switching primitives.
85 citations
TL;DR: In this paper, the preparation and characterization of Ca-alginate microspheres obtained by a new procedure from alginic acid, treated with an excess of NaOH and subsequently with a very concentrated solution of CaCl 2 are described.
84 citations
10 Aug 1998
TL;DR: The encoding format and data architecture designed especially for this corpus, which is generally usable for encoding linguistic corpora, and the methodology for the development of a harmonized set of morphosyntactic descriptions (MSDs), which builds upon the scheme for western European languages developed within the EAGLES project.
Abstract: The EU Copernicus project Multext-East has created a multi-lingual corpus of text and speech data, covering the six languages of the project: Bulgarian, Czech, Estonian, Hungarian, Romanian, and Slovene. In addition, wordform lexicons for each of the languages were developed. The corpus includes a parallel component consisting of Orwell's Nineteen Eighty-Four, with versions in all six languages tagged for part-of-speech and aligned to English (also tagged for POS). We describe the encoding format and data architecture designed especially for this corpus, which is generally usable for encoding linguistic corpora. We also describe the methodology for the development of a harmonized set of morphosyntactic descriptions (MSDs), which builds upon the scheme for western European languages developed within the EAGLES project. We discuss the special concerns for handling the six project languages, which cover three distinct language families.
82 citations
TL;DR: A series of language-theoretic properties of languages generated by systems with finite sets of axioms based on splicing rules of the form a, λ, where a is a symbol in a given set and λ is the empty string are investigated.
61 citations
TL;DR: In this article, it was shown that for two-dimensional Schrodinger operators with a nonzero constant magnetic field perturbed by a magnetic field and a scalar potential, both vanishing arbitrarily slow at infinity, the eigenfunctions corresponding to the discrete spectrum decay faster than any exponential.
Abstract: For two dimensional Schrodinger operators with a nonzero constant magnetic field perturbed by a magnetic field and a scalar potential, both vanishing arbitrarily slow at infinity, it is proved that eigenfunctions corresponding to the discrete spectrum decay faster than any exponential. Under more restrictive conditions on the perturbations, even quicker decay is obtained.
58 citations
16 Dec 1998
TL;DR: In this paper, the authors derived necessary and sufficient conditions for the existence of a stabilizing deterministic controller ensuring an imposed level of attenuation in terms of the solutions of two linear matrix inequalities satisfying a complementary rank condition.
Abstract: The aim of this paper is to develop an H/sub /spl infin//-type theory for discrete time time-varying systems with multiplicative noise. Based on a version of the bounded real lemma corresponding to this class of systems, necessary and sufficient conditions for the existence of a stabilizing deterministic controller ensuring an imposed level of attenuation are derived in terms of the solutions of two linear matrix inequalities (LMI) satisfying a complementary rank condition. Moreover, explicit formulae for such controller are obtained in the case when some additional conditions are assumed. As a particular case, we consider the same problem for discrete-time time-varying periodic systems with multiplicative noise, for which it is shown that a periodic /spl gamma/-attenuating controller may be computed as function of a certain extended LMI system.
TL;DR: In this article, a rehabilitation scheme is proposed for all affected areas, aiming at deactivating the pollution sources and rehabilitating the contaminated areas with remedial actions, which involves mainly removal of toxic and heavy elements from sulphidic tailings and leachates with biosorption and biosolubilisation techniques and development of a vegetative cover on phosphogypsum, cinders and sulphidics tailings.
TL;DR: In this paper, a minimizing movement model for quasi-static brittle crack evolution is proposed, where cracks appear and/or grow without any prescription of their shape or location when time-dependent displacements are imposed on the exterior boundary of the body.
Abstract: We propose a minimizing movement model for quasi-static brittle crack evolution. Cracks (fissures) appear and/or grow without any prescription of their shape or location when time-dependent displacements are imposed on the exterior boundary of the body. We use an energetic approach based on Mumford-Shah type functionals. By the discretization of the time variable we obtain a sequence of free discontinuity problems. We find exact solutions and estimations which lead us to the conclusion that in this model crack appearance is allowed but the constant of Griffith G and the critical stress which causes the fracture in an uni-dimensional traction experiment cannot be both constants of material. A weak formulation of the model is given in the frame of special functions with bounded deformation. We prove the existence of weak constrained incremental solutions of the model. A partial existence result for the minimizing movement model is obtained under the assumption of uniformly bounded (in time) power communicated to the body by the rest of the universe. The model is of applicative interest. A numerical approach and examples, using an Ambrosio–Tortorelli variational approximation of the energy functional, are given in the last section.
TL;DR: In this article, the authors consider polynomial mappings which have atypical fibres due to the asymptotic behavior at infinity and study the localizability at infinity of the variation of topology of fibres and the possibility of interpreting local results at infinity into global results.
Abstract: We consider polynomial mappings which have atypical fibres due to the asymptotic behavior at infinity. Fixing some proper extension of the polynomial mapping, we study the localizability at infinity of the variation of topology of fibres and the possibility of interpreting local results at infinity into global results. We prove local and global Bertini–Sard–Lefschetz type statements for noncompact spaces and nonproper mappings and we deduce results on the homotopy type or the connectivity of the fibres of polynomial mappings.
TL;DR: It is proved here that each recursively enumerable language can be written as the weak coding of the image by an inverse morphism of a language generated by an insertion grammar (with the maximal length of strings u, v as above equal to seven).
TL;DR: In this paper, the distribution of the number of dierences in the interval (n,n + t), 1 n p, where t p/m/m is a positive constant.
Abstract: In this paper we study the distribution of the number of ’s in the interval (n,n + t], 1 n p, where t p/’ (p 1) and is a positive constant. We show that if ’(p 1)/p is small then the distribution is approximately that of a Poisson variable with parameter . Next we consider the proportion of dierences i+1 i which are at least times greater than the average, that is, (1) gp( ) = #{i : 1 i ’(p 1), i+1 i p/’ (p 1)} ’(p 1)
TL;DR: In this article, the existence of the thermodynamic potentials, internal energy U and entropy S as functions of state ( ϱ, T, p ) is required such that certain relations between their rates and the rates of heat and work are verified.
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TL;DR: Characterizations of regular, linear, and recursively enumerable languages are obtained in this framework of sticker systems, an abstraction of the way that the WatsonCrick complementarity is used in DNA computing.
Journal Article•
TL;DR: The paper discusses some classes of contextual grammars---mainly those with "maximal use of selectors"---giving some arguments that these Grammars can be considered a good model for natural language syntax, and some ideas for associating a structure to the generated words, in the form of a tree, or of a dependence relation.
Abstract: The paper discusses some classes of contextual grammars---mainly those with "maximal use of selectors"---giving some arguments that these grammars can be considered a good model for natural language syntax.A contextual grammar produces a language starting from a finite set of words and interatively adding contexts to the currently generated words, according to a selection procedure: each context has associated with it a selector, a set of words; the context is adjoined to any occurrence of such a selector in the word to be derived. In grammars with maximal use of selectors, a context is adjoined only to selectros for which no superword is a selector. Maximality can be defined either locally or globally (with respect to all selectors in the grammar). The obtained families of languages are incomparable with that of Chomsky context-free languages (and with other families of languages that contain linear languages and that are not "too large"; see Section 5) and have a series of properties supporting the assertion that these grammars are a possible adequate model for the syntax of natural languages. They are able to straightforwardly describe all the usual restrictions appearing in natural (and artificial) languages, which lead to the non-context-freeness of these languages: reduplication, crossed dependencies, and multiple agreements; however, there are center-embedded constructions that cannot be covered by these grammars.While these assertions concern only the weak generative capacity of contextual grammars, some ideas are also proposed for associating a structure to the generated words, in the form of a tree, or of a dependence relation (as considered in descrpitive linguistics and also similar to that in link grammars).
TL;DR: In this article, the thermal treatment schedule of the pressed powder mixtures has been established according to the results of differential thermal and thermogravimetric analysis (DTA/TGA) and the formation of the compound has been followed by XRD, dimensional variation of the samples and apparent density measurements.
Abstract: Individual Al2O3, TiO2 and SiO2, as well as binary Al2O3-TiO2 powders have been obtained by sol-gel method, polymeric route. The obtained powders have been characterized by X-ray diffraction (XRD), IR-spectrometry and transmission electron microscopy (TEM) methods. In the used experimental conditions amorphous, submicronic, monodisperse powders have been obtained. The preparation of Al2TiO5 and of some compositions situated in the Al2TiO5-Al6Si2O13 pseudobinary system has been realized by solid-state reaction starting with the mentioned above powders. The thermal treatment schedule of the pressed powder mixtures has been established according to the results of differential thermal and thermogravimetric analysis (DTA/TGA). The formation of the compound has been followed by XRD, dimensional variation of the samples and apparent density measurements. The results obtained starting with reactive powders have been compared with those obtained starting with commercial powders. The samples have shown a high reactivity and the formation of tialite was enhanced. However the sintering tendency was not essentially increased.
TL;DR: In this article, a second order elliptic equation in divergence form in ℝ3 was constructed, with a nonzero solution which vanishes in a half-space, and the coefficients were α-Holder continuous of any order α < 1.
Abstract: We construct a second order elliptic equation in divergence form inℝ3, with a nonzero solution which vanishes in a half-space.The coefficients are α-Holder continuous of any order α< 1. This improves a previous counterexample of Miller (1972, 1974).Moreover, we obtain coefficients which belong to a finer class ofsmoothness, expressed in terms of the modulus of continuity.
TL;DR: The dielectric properties of yeast cells in the absence and presence of cetyltrimethylammonium bromide (CTAB) were investigated and the specific capacitance of the vacuole membrane was nearly constant over the whole surfactant concentration range.
TL;DR: In this article, it was proved that the subspaces corresponding to bounded, isolated parts of the spectrum of (periodic and nonperiodic) one-dimensional Schrodinger operators admit bases of exponentially localised functions (generalised Wannier functions).
Abstract: It is proved that the subspaces corresponding to bounded, isolated parts of the spectrum of (periodic and nonperiodic) one-dimensional Schrodinger operators admit bases of exponentially localised functions (generalised Wannier functions).
TL;DR: The reverse micelles of triblock copolymers poly(ethylene oxide)-block-poly(propylene oxide)-poly(poly(ethylenox)-blockpoly(pluronic) EO6PO36EO6 and EO13PO30EO13 (Pluronic L64) were investigated by fluorescence, absorption, and spin probe techniques in ternary copolymer/o-xylene/water systems with different water contents.
Abstract: The reverse micelles of triblock copolymers poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) EO6PO36EO6 (Pluronic L62) and EO13PO30EO13 (Pluronic L64) in ternary (copolymer/o-xylene/water) and binary (copolymer/water) systems with different water contents were evidenced and investigated by fluorescence, absorption, and spin probe techniques. The spectral parameters of the polarity sensitive probes, 1-anilinonaphthalene-8-sulfonic acid (ANS), dansylhexadecylamine (Dansyl), pyrenesulfonic acid (PSA), 4-nitropyridine N-oxide (NP) and 4-(N,N‘-dimethyl-N-alkyl)ammonium 2,2‘,6,6‘-tetramethylpiperidine-1-oxyl iodide (CAT n), were related to the local hydration and polarity by comparison with a series of poly(oxyethylene)/water (TEG/water) calibration mixtures. The data were concordant and complementary, resulting in polarity profiles of the core for all systems and the relative radial positioning of the probes. The order of decreasing hydrophobic character found was Dansyl > NP > CAT 1...
TL;DR: In this paper, the authors define distinguished sequences and prove that they permit to construct transcendental elements and also to associate to any transcendental element an infinite set of numerical invariants.
TL;DR: A generalization of the quasi-Hopf algebra D ω(G) is presented in this article, where the authors show that it is possible to generalize the quasi hopf algebra to a quasi-hopf algebra.
Abstract: (1998). A generalization of the quasi-Hopf algebra D ω(G) Communications in Algebra: Vol. 26, No. 12, pp. 4125-4141.
TL;DR: In this article, the influence of thermal treatments on the structural and textural properties of the sol-gel TiO2 films obtained from Ti(OC3H7i)4 was studied.
Abstract: Atomic Force Microscopy (AFM) was used to study the influence of thermal treatments on the structural and textural properties of the sol-gel TiO2 films obtained from Ti(OC3H7i)4. X-ray diffraction (XRD), ellipsometric and porosity measurements have also been made. The TiO2 sol-gel films were homogeneous, transparent and amorphous. Heat treatments in the 400–600°C range indicate that the films have a strong tendency to crystallization. The high initial homogeneity of the TiO2 films was preserved during the crystallization process. AFM shows that the thermally treated films exhibit uniform, monodispersed crystals.
TL;DR: In this paper, the spin probe technique has been used for structural characterization of self-assembled systems, in general, and of those of PEO surfactants, in particular, by using specific ESR parameters (the nitrogen hyperfine splitting (hfs), a N, the rotational correlation time, τ c, the order parameter, S ) of a variety of properly chosen nitroxides, problems such as hydration degree and profile of the PEO chains, ordering and order profile along these chains, their penetrability by the oil solvent, role of the terminal
TL;DR: In this paper, the authors studied the normalization obtained by C. D. Foias and J. C. Saut for the Navier-Stokes equations in the classical case of analytic ODEs in the neighborhood of a stationary point and showed that in this general (finite-dimensional) case, this normalization coincides with the distinguished normalization in the sense of A. Brjuno.
Abstract: We study the normalization obtained by C. Foias and J. C. Saut for the Navier–Stokes equations in the classical case of analytic ordinary differential equations in the neighborhood of a stationary point. We show that in this general (finite-dimensional) case, this normalization coincides with the distinguished normalization in the sense of A. D. Brjuno. Moreover, their approach leads to a spectral formula for the (inverse of the) distinguished normalizing map. In the particular case of an asymptotically stable, by linearization, stationary point, the Foias–Saut device gives the inverse of the already known link between the Lyapunov exponential expansion and normalization.
TL;DR: In this paper, the authors used the general thermodynamic restrictions on a shearless rate-type fluid obtained in part I of this paper together with a so called extended Holtzmann law to get specific forms of the constitutive functions.