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Novel Properties (novel + property)
Selected AbstractsDinucleoside polyphosphates stimulate the primer independent synthesis of poly(A) catalyzed by yeast poly(A) polymeraseFEBS JOURNAL, Issue 21 2002Marķa A. Günther Sillero Novel properties of the primer independent synthesis of poly(A), catalyzed by the yeast poly(A) polymerase are presented. The commercial enzyme from yeast, in contrast to the enzyme from Escherichia coli, is unable to adenylate the 3,-OH end of nucleosides, nucleotides or dinucleoside polyphosphates (NpnN). In the presence of 0.05 mm ATP, dinucleotides (at 0.01 mm) activated the enzyme velocity in the following decreasing order: Gp4G, 100; Gp3G, 82; Ap6A, 61; Gp2G, 52; Ap4A, 51; Ap2A, 41; Gp5G, 36; Ap5A, 27; Ap3A, 20, where 100 represents a 10-fold activation in relation to a control without effector. The velocity of the enzyme towards its substrate ATP displayed sigmoidal kinetics with a Hill coefficient (nH) of 1.6 and a Km(S0.5) value of 0.308 ± 0.120 mm. Dinucleoside polyphosphates did not affect the maximum velocity (Vmax) of the reaction, but did alter its nH and Km(S0.5) values. In the presence of 0.01 mm Gp4G or Ap4A the nH and Km(S0.5) values were (1.0 and 0.063 ± 0.012 mm) and (0.8 and 0.170 ± 0.025 mm), respectively. With these kinetic properties, a dinucleoside polyphosphate concentration as low as 1 µm may have a noticeable activating effect on the synthesis of poly(A) by the enzyme. These findings together with previous publications from this laboratory point to a potential relationship between dinucleoside polyphosphates and enzymes catalyzing the synthesis and/or modification of DNA or RNA. [source] Novel properties of wave propagation in biaxially anisotropic left-handed materialsANNALEN DER PHYSIK, Issue 6 2004J.Q. Shen Abstract Some physically interesting properties and effects (including the quantum effects) of wave propagation in biaxially anisotropic left-handed materials are investigated in this paper: (i) we show that in the biaxially gyrotropic left-handed material, the left-right coupling of circularly polarized light arises due to the negative indices in permittivity and permeability tensors of gyrotropic media; (ii) it is well known that the geometric phases of photons inside a curved fiber in previous experiments often depend on the cone angles of solid angles subtended by a curve traced by the direction of wave vector of light, at the center of photon momentum space. Here, however, for the light propagating inside certain anisotropic left-handed media we will present a different geometric phase that is independent of the cone angles; (iii) the extra phases of electromagnetic wave resulting from the instantaneous helicity inversion at the interfaces between left- and right-handed (LRH) media is also studied in detail by using the Lewis-Riesenfeld invariant theory. Some interesting applications (e.g., controllable position-dependent frequency shift, detection of quantum-vacuum geometric phases and helicity reversals at the LRH interfaces etc.) of above effects and phenomena in left-handed media is briefly discussed. [source] Versatile, Benzimidazole/Amine-Based Ambipolar Compounds for Electroluminescent Applications: Single-Layer, Blue, Fluorescent OLEDs, Hosts for Single-Layer, Phosphorescent OLEDsADVANCED FUNCTIONAL MATERIALS, Issue 16 2009Chih-Hsin Chen Abstract A series of compounds containing arylamine and 1,2-diphenyl-1H -benz[d]imidazole moieties are developed as ambipolar, blue-emitting materials with tunable blue-emitting wavelengths, tunable ambipolar carrier-transport properties and tunable triplet energy gaps. These compounds possess several novel properties: (1) they emit in the blue region with high quantum yields; (2) they have high morphological stability and thermal stability; (3) they are capable of ambipolar carrier transport; (4) they possess tunable triplet energy gaps, suitable as hosts for yellow-orange to green phosphors. The electron and hole mobilities of these compounds lie in the range of 0.68,144,×,10,6 and 0.34,147,×,10,6,cm2 V,1 s,1, respectively. High-performance, single-layer, blue-emitting, fluorescent organic light-emitting diodes (OLEDs) are achieved with these ambipolar materials. High-performance, single-layer, phosphorescent OLEDs with yellow-orange to green emission are also been demonstrated using these ambipolar materials, which have different triplet energy gaps as the host for yellow-orange-emitting to green-emitting iridium complexes. When these ambipolar, blue-emitting materials are lightly doped with a yellow-orange-emitting iridium complex, white organic light-emitting diodes (WOLEDs) can be achieved, as well by the use of the incomplete energy transfer between the host and the dopant. [source] Colloidal-Crystal-Assisted Patterning of Crystalline MaterialsADVANCED MATERIALS, Issue 13 2010Cheng Li Abstract Colloidal crystals have shown great potential as versatile templates for the fabrication of patterned micro- and nanostructures with complex architectures and novel properties. The patterning of functional crystalline materials in two and three dimensions is essential to the realization of their applications in many technologically important fields. This article highlights some recent progress in the fabrication of 2D and 3D patterned crystalline materials with the assistance of colloidal crystals. By combining a bioinspired synthetic strategy based on a transient amorphous phase with a colloidal-crystal templating method, unique 3D ordered macroporous (3DOM) calcite single crystals can be created. Moreover, patterned arrays of regular ZnO nanopillars with controlled size, shape, and orientation can be fabricated via a facile wet chemical approach by using masks derived from monolayer colloidal crystals (MCC). [source] INTELLECTUAL HISTORY, INCONCEIVABILITY, AND METHODOLOGICAL HOLISM,HISTORY AND THEORY, Issue 1 2007BRANKO MITROVI ABSTRACT The debate between individualism and holism in the philosophy of history pertains to the nature of the entities relied on in historical explanations. The question is whether explanations of historical items (for example, events, actions, artifacts) require the assumption that the collective historical entities (for example, civilizations, cultures, and so on) used in these explanations are (sometimes) conceived of as irreducible to the actions, thoughts, and beliefs of individual human beings. In this paper I analyze two methodological problems that holist explanations face in the writing of intellectual history. The first problem derives from the fact that holist explanations in intellectual history have to rely on the claim that certain beliefs were inconceivable to some individuals because they were members of specific collectives, whereas it is unclear how historical research can justify such claims when made from the holist position. The second problem pertains to the difficulties the holist position faces when it has to account for the novel properties of artifacts studied by intellectual history. [source] Novel Multifunctional Properties Induced by Interface Effects in Perovskite Oxide HeterostructuresADVANCED MATERIALS, Issue 45 2009Kui-juan Jin Abstract Multilayer structures have emerged as a leading research topic and researchers expect that multilayers may lead to interesting artificial materials with novel properties. In this Research News we show that the introduction of interfaces into perovskite oxides can induce a series of novel properties including an unusual positive magnetoresistance, great enhancement of lateral photovoltage in La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3, and an electrical modulation of the magnetoresistance in multi-p-n heterostructures of SrTiO3,,/La0.9Sr0.1MnO3/SrTiO3,,/La0.9Sr0.1MnO3/Si. This novel positive magnetoresistance is attributed to the creation of a space charge region at the interface where the spin of the carriers is anti-parallel to that of the carriers in the region far from the interface of manganese oxide in the heterostructures. [source] Potential prospects of chitosan derivative trimethyl chitosan chloride (TMC) as a polymeric absorption enhancer: synthesis, characterization and applicationsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 9 2008Jasjeet K. Sahni ABSTRACT In recent years, researchers have been working extensively on various novel properties of polymers to develop increased efficiency of drug delivery and improve bioavailability of various drug molecules, especially macromolecules. Chitosan, a naturally occurring polysaccharide, because of its protonated/polymeric nature, provides effective and safe absorption of peptide and protein drugs. Its transmucosal absorption is, however, limited to acidic media because of its strong intermolecular hydrogen bonds. A new partially quaternized chitosan derivative, N-trimethyl chitosan chloride (TMC), has been synthesized with improved solubility, safety and effectiveness as an absorption enhancer at neutral pH and in aqueous environment. It enhances the absorption, especially of peptide drugs, by reversible opening of tight junctions in between epithelial cells, thereby facilitating the paracellular diffusion of peptide drugs. This derivative thus opens new perspectives as a biomaterial for various pharmaceutical applications/drug delivery systems. This review deals with the potential use of the quaternized chitosan derivative as a permeation enhancer for the mucosal delivery of macromolecular drugs along with its other biomedical applications. [source] Digital artifacts as quasi-objects: Qualification, mediation, and materialityJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 12 2009Hamid R. Ekbia Digital artifacts have novel properties that largely derive from the processes that mediate their creation, and that can be best understood by a close examination of such processes. This paper introduces the concept of "quasi-object" to characterize these objects and elucidate the activities that comprise their mediations. A case study of "bugs" is analyzed to illustrate exemplary activities of justification, qualification, and binding in the process of bug fixing in Free/Open Source Software development. The findings of the case study lead to broader reflections on the character of digital artifacts in general. The relationship of "quasi-object" to other similar concepts are explored. [source] High-dispersion spectroscopy of two A supergiant systems in the Small Magellanic Cloud with novel propertiesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2010R. E. Mennickent ABSTRACT We present the results of a spectroscopic investigation of two novel variable bright blue stars in the SMC, OGLE004336.91-732637.7 (SMC-SC3) and the periodically occulted star OGLE004633.76-731204.3 (SMC-SC4), whose photometric properties were reported by Mennickent et al. (2010). High-resolution spectra in the optical and far-UV show that both objects are actually A + B type binaries. Three spectra of SMC-SC4 show radial velocity variations, consistent with the photometric period of 184.26 d found in Mennickent et al. 2010. The optical spectra of the metallic lines in both systems show combined absorption and emission components that imply that they are formed in a flattened envelope. A comparison of the radial velocity variations in SMC-SC4 and the separation of the V and R emission components in the H, emission profile indicate that this envelope, and probably also the envelope around SMC-SC3, is a circumbinary disc with a characteristic orbital radius some three times the radius of the binary system. The optical spectra of SMC-SC3 and SMC-SC4 show, respectively, He i emission lines and discrete blue absorption components (BACs) in metallic lines. The high excitations of the He i lines in the SMC-SC3 spectrum and the complicated variations of Fe ii emission and absorption components with orbital phase in the spectrum of SMC-SC4 suggests that shocks occur between the winds and various static regions of the stars' corotating binary-disc complexes. We suggest that BACs arise from wind shocks from the A star impacting the circumbinary disc and a stream of former wind-efflux from the B star accreting on to the A star. The latter picture is broadly similar to mass transfer occurring in the more evolved (but less massive) algol (B/A + K) systems, except that we envision transfer occurring in the other direction and not through the inner Lagrangian point. Accordingly, we dub these objects prototype of a small group of Magellanic Cloud wind-interacting A + B binaries. [source] | |||||||||||||