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Showing papers by "Romanian Academy published in 2005"


Journal ArticleDOI
TL;DR: The Global energy system transition from fossil fuel to hydrogen utilization is described in this paper, and the benefits of the combustion of hydrogen are reported. And the atomic hydrogen/carbon ratio and chemical properties of hydrogen is described.

868 citations


Journal ArticleDOI
TL;DR: In this article, a concise overview is given on mononuclear and dinuclear, bidentate Schiff base ruthenium complexes with different additional ligands and their applications in various chemical transformations such as Kharasch addition, enol-ester synthesis, alkyne dimerization, olefin metathesis and atom transfer radical polymerization.

218 citations


Journal ArticleDOI
TL;DR: In this article, the chitosan-carboxymethylcellulose interaction was studied in solution by conductometric, potentiometric and turbidimetric titration, and in the solid phase by FTIR spectra or thermogravimetric analysis.

146 citations



Journal ArticleDOI
TL;DR: This milestone report describes the main problems, such as management of complexity, scalability, increasing costs, coordination, market-based resource allocation, and more in the next generation manufacturing system.

91 citations


Journal ArticleDOI
TL;DR: The synthesis of Schiff base mononuclear and binuclear ruthenium complexes, whose additional ligands around the metal core have been selected from an array of motifs, is described in this paper.
Abstract: The synthesis of various Schiff base mononuclear and binuclear ruthenium complexes, whose additional ligands around the metal core have been selected from an array of motifs, is described. These types of ruthenium complexes, conveniently prepared from commonly available ruthenium sources, are rather stable, display good tolerance towards diverse organic functionalities and also to air and moisture. Remarkably, they exhibit a high activity and chemoselectivity in a variety of catalytic processes such as ring-closing metathesis (RCM), Kharasch addition, alkyne dimerization, enol ester synthesis, ring-opening metathesis polymerization (ROMP) and atom-transfer radical polymerization (ATRP). This review covers both homogeneous and heterogeneous hybrid Schiff base-ruthenium complexes.

83 citations


Journal ArticleDOI
TL;DR: The current perception of the RAS is therefore that of a much more complex system than previously believed, with autocrine, paracrine and endocrine properties extending beyond the cardiovascular system.
Abstract: The concept of tissue renin-angiotensin systems (RAS) is now well established and it is now usual to think in terms of renal and tissue systems. At the same time it has emerged that angiotensin II (Ang II) is not the only biologically active peptide generated by the RAS. At least three others have been identified: the heptapeptide Ang III, the hexapeptide Ang IV and Ang 1-7. Specific receptors exits for the last two peptides. In addition, the range of possible physiological and pathophysiological properties for Ang II has been expanding. The current perception of the RAS is therefore that of a much more complex system than previously believed, with autocrine, paracrine and endocrine properties extending beyond the cardiovascular system. This mini-review focuses on the synthetic pathways of the Ang peptides and describes some of their pleiotropic actions.

81 citations


Journal ArticleDOI
TL;DR: In this article, the effect of various boundary conditions (bounce back and three versions of diffuse reflection) for the two-dimensional first-order upwind finite difference Lattice Boltzmann model was studied.

73 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the sediment-bound metal concentrations in the Abrud and Aries river system in western Romania and identified four chemical phases: (1) exchangeable, (2) Fe/Mn oxides, (3) organic matter/sulphides and (4) residual.

72 citations


Journal ArticleDOI
TL;DR: Dopachrome tautomerase is a type I membrane protein and an important regulatory enzyme that plays a pivotal role in the biosynthesis of melanin and in the rapid metabolism of its toxic intermediates and the enzymatic activity of Dct may play a role in determining whether the eumelan in or pheomelanin pathway is preferred for pigment biosynthesis.
Abstract: Dopachrome tautomerase (Dct) is a type I membrane protein and an important regulatory enzyme that plays a pivotal role in the biosynthesis of melanin and in the rapid metabolism of its toxic intermediates. Dct-mutant melanocytes carrying the slaty or slaty light mutations were derived from the skin of newborn congenic C57BL/6J non-agouti black mice and were used to study the effect(s) of these mutations on the intracellular trafficking of Dct and on the pigmentation of the cells. Dct activity is 3-fold lower in slaty cells compared with non-agouti black melanocytes, whereas slaty light melanocytes have a surprisingly 28-fold lower Dct activity. Homology modelling of the active site of Dct suggests that the slaty mutation [R194Q (Arg194→Gln)] is located in the active site and may alter the ability of the enzyme to transform the substrate. Transmembrane prediction methods indicate that the slaty light mutation [G486R (Gly486→Arg)] may result in the sliding of the transmembrane domain towards the N-terminus, thus interfering with Dct function. Chemical analysis showed that both Dct mutations increase pheomelanin and reduce eumelanin produced by melanocytes in culture. Thus the enzymatic activity of Dct may play a role in determining whether the eumelanin or pheomelanin pathway is preferred for pigment biosynthesis.

68 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the structure of F-finite, F-pure rings R by studying how the numbers aq grow with respect to q. This growth is quantified by the splitting dimension and the splitting ratios of R which they study in detail.
Abstract: For a reduced F-finite ring R of characteristic p>0 and q=pe one can write Open image in new window where Mq has no free direct summands over R. We investigate the structure of F-finite, F-pure rings R by studying how the numbers aq grow with respect to q. This growth is quantified by the splitting dimension and the splitting ratios of R which we study in detail. We also prove the existence of a special prime ideal Open image in new window(R) of R, called the splitting prime, that has the property that R/Open image in new window(R) is strongly F-regular. We show that this ideal captures significant information with regard to the F-purity of R.

Journal ArticleDOI
TL;DR: The implementation of diffuse reflection boundary conditions in a thermal lattice Boltzmann model for which the upwind finite difference scheme is used to solve the set of evolution equations recovered after discretization of the velocity space is discussed.
Abstract: We discuss the implementation of diffuse reflection boundary conditions in a thermal lattice Boltzmann model for which the upwind finite difference scheme is used to solve the set of evolution equations recovered after discretization of the velocity space. Simulation of heat transport between two parallel walls at rest shows evidence of temperature jumps at the walls that increase with Knudsen number. When the walls move in opposite directions with speeds $\ifmmode\pm\else\textpm\fi{}{u}_{W}$, fluid velocity slip is observed at the walls, together with temperature jumps.

Journal ArticleDOI
TL;DR: It is shown that fast mobility of clusters larger than a single atom is essential to bring the theoretical results into agreement with the outcome of molecular beam epitaxy experiments.
Abstract: The diffusion of small palladium clusters on MgO(100) is theoretically investigated. It is found that small clusters can diffuse even faster than isolated adatoms by a variety of mechanisms (some of which are novel), such as dimer rotation, trimer walking, tetramer rolling, and sliding. The consequences of the diffusion of small clusters on the growth of Pd aggregates on MgO(100) are investigated, and it is shown that fast mobility of clusters larger than a single atom is essential to bring the theoretical results into agreement with the outcome of molecular beam epitaxy experiments.

Journal ArticleDOI
TL;DR: The results support the hypothesis that a number of pathogenicity factors of cyst nematodes is of procaryotic origin and were acquired by horizontal gene transfer.

Journal ArticleDOI
TL;DR: The key factors for the successful preparation were also the viscosity of the polymer, while the wettability of the resulted microcapsules, the temperature of the preparation, and the porosity have modulated the release of the drug.

Journal ArticleDOI
TL;DR: In this paper, a mixture of silica, organic, and carbon aerogels with metallic Ni and Pd was synthesized by impregnation, with Ni(acac)2 or Pd(acAC)2, of the silica wet gels followed by ethanol supercritical drying.
Abstract: We have prepared silica, organic, and carbon aerogels doped with metallic Ni and Pd through sol-gel processes. Silica aerogel nanocomposites have been synthesized by impregnation, with Ni(acac)2 or Pd(acac)2, of the silica wet gels followed by ethanol supercritical drying. Organic aerogels were prepared by sol-gel copolymerization of formaldehyde with the potassium salt of 2,4-dihydroxybenzoic acid, followed by ion exchange with either Ni(NO3)2·6H2O or Pd(OAc)2 and CO2 supercritical drying. No special reduction step was needed. Organic aerogels were further carbonized to obtain carbon aerogels. Pd organic and carbon aerogels containing 20–40% palladium nanoparticles are good catalysts for the Mizoroki–Heck reaction.

Journal ArticleDOI
TL;DR: In this article, the authors studied the dynamic properties of EUV spicules seen at the solar limb and found that spicule occurrence occurs repeatedly at the same location with a birth rate of around 0.16/min as estimated at 10 �� above the limb and a lifetime ranging from 15 down to 3 min.
Abstract: Here we study the dynamic properties of EUV spicules seen at the solar limb. The selected data were obtained as time series in polar coronal holes by SUMER/SoHO. The short exposure time and the almost fixed position of the spectrometer's slit allow the analysis of spicule properties such as occurrence, lifetime and Doppler velocity. Our data reveal that spicules occur repeatedly at the same location with a birth rate of around 0.16/min as estimated at 10 �� above the limb and a lifetime ranging from 15 down to≈3 min. We are able to see some spicules showing a process of "falling after rising" indicated by the sudden change of the Doppler velocity sign. A periodicity of ≈5 min is sometimes discernible in their occurrence. Most spicules have a height between 10 �� and 20 �� above the limb. Some can stretch up to 40 �� ; these "long macro-spicules" seem to be comprised of a group of high spicules. Some of them have an obvious periodicity in the radiance of ≈ 5m in.

Journal ArticleDOI
TL;DR: In this paper, high surface area boron nitride powders were obtained using polytrichoroborazine, pTCB, as precursor, leading to a surface area higher than 150m2/g.

Journal ArticleDOI
11 May 2005-Polymer
TL;DR: In this article, the effects of varying hard and soft segment chemistry, crosslinking and preparation procedures, on the mechanical response of melt-cast polyurethane elastomers were made.

Journal ArticleDOI
TL;DR: In this paper, the authors used anodic voltammetry to investigate the oxidation of thiourea (TU) at boron-doped diamond (BDD) electrodes.
Abstract: The oxidation of thiourea (TU) at boron-doped diamond (BDD) electrodes was investigated by the use of anodic voltammetry. The results indicated that the overall TU oxidation reaction is rather complicated and takes place via two steps: a slow electron-transfer yielding the corresponding free radical, followed by a fast oxidation of this radical, prior to its dimerization. It was found that in acidic media the voltammetric response is suitable for analytical applications, and unlike glassy carbon (GC), BDD electrodes exhibit very low susceptibility to adsorption. The same conclusion was supported by the results of AC voltammetric measurements. Based upon the voltammetric peak for the first step of TU oxidation, a method is proposed for the determination of this compound in the micromolar concentration range. The analytical performance characteristics of the method are comparable to those reported for TU determination by the use of platinum electrodes or enzyme-modified platinum electrodes.

Book ChapterDOI
T. Birsan, Dan Tiba1
18 Jul 2005
TL;DR: This paper recalls the work of D. Pompeiu who introduced the notion of set distance in his thesis published one century ago and it is frequently called the Hausdorff distance.
Abstract: This paper recalls the work of D. Pompeiu who introduced the notion of set distance in his thesis published one century ago. The notion was further studied by F. Hausdorff, C. Kuratowski who acknowledged in their books the contribution of Pompeiu and it is frequently called the Hausdorff distance.

Journal ArticleDOI
TL;DR: In this article, it was proved that all correlations of the sequence of Farey fractions exist and explicit formulas for the correlation measures were provided for correlation measures, and it was shown that all correlation measures for the Farey fraction sequence of fractions exist.
Abstract: It is proved that all correlations of the sequence of Farey fractions exist and explicit formulas are provided for the correlation measures.

Journal ArticleDOI
TL;DR: EPR spectroscopy was used to study formation of inclusion complexes of monofunctionalised spin-labelled beta-cyclodextrins; this method is very sensitive to the interactions of cyclodextRins with large guest molecules.
Abstract: EPR spectroscopy was used to study formation of inclusion complexes of monofunctionalised spin-labelled β-cyclodextrins; this method is very sensitive to the interactions of cyclodextrins with large guest molecules.

Journal ArticleDOI
TL;DR: In this article, the antitumor effect of a magnetic fluid was studied after direct inoculation into cat mammary tumors, and an external magnetic field was used to retain the nanoparticles in the tumor tissue.

Journal ArticleDOI
TL;DR: In this article, a 2 × 2 system of semilinear partial differential equations of parabolic-type describing interactions between a prey population and a predator population, featuring a Holling-type II functional response to predation, is considered.
Abstract: In this work we consider a 2 × 2 system of semilinear partial differential equations of parabolic-type describing interactions between a prey population and a predator population, featuring a Holling-type II functional response to predation. We address the question of stabilizing the predator population to zero, upon using a suitable internal control supported on a small subdomain ω of the whole spatial domain Ω , and acting on predators. We give necessary and sufficient conditions for this stabilizability result to hold.

Journal ArticleDOI
TL;DR: This paper investigates the power and the efficiency of P systems with active membranes by first proving that they can simulate and give a direct and simple proof for the universality result – without using division rules.
Abstract: P systems with active membranes are among the central ones in membrane computing, and they were shown to be both computationally universal (able to simulate Turing machines) and computationally efficient (able to solve hard problems in polynomial time). However, in all cases, these results were obtained by making use of several powerful features, such as membrane polarization, label changing, division of non-elementary membranes, priorities, or cooperative rules. This paper contributes to the research effort of introducing a class of P systems with active membranes having none of the features mentioned above, but still preserving the power and the efficiency. The additional feature we consider instead are the operations of endocytosis and exocytosis: moving a membrane inside a neighboring membrane, or outside the membrane where it is placed. We investigate the power and the efficiency of these systems (also using membrane division) by first proving that they can simulate (with a linear slowdown and without introducing non-determinism) rewriting P systems with 2-replication, for which the universality and the possibility of solving NP-complete problems in polynomial time are known. In this way, the universality and efficiency are also obtained for our systems. We also give a direct and simple proof for the universality result --- without using division rules (the proof uses nine membranes, but we do not know whether this number can be decreased).

Journal ArticleDOI
TL;DR: In this paper, the authors present several classes of real Banach Lie-Poisson spaces whose characteristic distributions are integrable, the integral manifolds being symplectic leaves just as in finite dimensions, and investigate when these leaves are embedded submanifolds or when they have Kahler structures.
Abstract: We present several large classes of real Banach Lie–Poisson spaces whose characteristic distributions are integrable, the integral manifolds being symplectic leaves just as in finite dimensions. We also investigate when these leaves are embedded submanifolds or when they have Kahler structures. Our results apply to the real Banach Lie–Poisson spaces provided by the self-adjoint parts of preduals of arbitrary W*-algebras, as well as of certain operator ideals.


Proceedings ArticleDOI
25 Sep 2005
TL;DR: This paper proves that the (conceptual, formal, graphical) language of membrane computing can be useful for economics, and introduces a class of P systems (with bi-rules), which capture features of economic processes which cannot be covered by the "standard" P systems.
Abstract: This paper is a first step towards a systematic evaluation of the possibilities to use membrane computing as a modeling framework for economics. We start by a simple interpretation of several basic ingredients of membrane computing in economic terms, thus proving that the (conceptual, formal, graphical) language of membrane computing can be useful for economics, and then we introduce a class of P systems (with bi-rules), which capture features of economic processes which cannot be covered by the "standard" P systems. A simple illustration of the versatility of this formalism is also given.

Journal ArticleDOI
TL;DR: In this paper, the behavior of two semi-interpenetrating polymer networks (S-IPNs) based on polyurethane (PU) and epoxy maleate of bisphenol A (EMBA) under exposure to UV radiation for long period of times (up to 200h) was investigated.
Abstract: The behavior of two semi-interpenetrating polymer networks (S-IPNs) based on polyurethane (PU) and epoxy maleate of bisphenol A (EMBA) under exposure to UV radiation for long period of times (up to 200 h) was investigated. The networks obtained by the specific mixture under certain thermal treatment included in their structures crosslinked EMBA and linear PU. Advanced photooxidative degradation took place for long time of UV irradiation (over 160 h, especially), with almost a total destruction of the raw structures. The important modification of both the surface and of the morphology of the tested samples with the time of irradiation was also analyzed. Simultaneously, as compared to results obtained for short time of UV radiations (up to 10 h), where the mechanical properties of the tested samples improved, long time of UV radiations led to deterioration of many of the mechanical properties.