On boundary value problem with singular inhomogeneity concentrated on the boundary

We study the asymptotic behavior of solutions to a boundary value problem for the Poisson equation with a singular right-hand side, singular potential and with alternating type of the boundary condition. Assuming that the boundary microstructure is periodic, we construct the limit problem and prove the homogenization theorem by means of the unfolding method. The proof requires that the dimension be larger than two.     

The Surface Wettability and Adhesion of Poly(Ester Urethane)s and Poly(Ether Urethane)s

In this study the wetting characteristics of untreated and plasma-treated polyurethane thin films were investigated. The degree of wettability was investigated by measuring the contact angle formed between a liquid drop and the solid surface. The work of adhesion, interfacial free energy, spreading coefficient, and Girifalco–Good's interaction parameter changed significantly for plasma-treated polyurethane films. Both complete and partial wetting were analyzed from the spreading coefficient of liquid drops on the solid substrate.     

Mesoporous aluminosilicate macrospheres obtained by spray gelling technique

Journal of Sol-Gel Science and Technology - Porous aluminosilicate macrospheres were prepared by spray gelling technique using chitosan, chitosan and yeast cells and respectively chitosan, yeast...     

含液晶成分的掺杂共聚物和胆甾醇基棕榈酸盐(或酯)掺合物(英文)

pacc:7855K Physicalblendscontainingmacromolecular compoundsandlowmolecularweightliquidcrys tals(LCs)haveimportantapplications.LCsare usedasreinforcementsforamorphouspolymersor indisplaydevices.TheadditionofLCstoamor phouspolymersdeterminesimprovementsin…     

Synthesis,characterization, crystal structure and toxicity evaluation of Co (II), Cu (II), Mn (II), Ni (II), Pd (II) and Pt (II) complexes with Schiff base derived from 2-chloro-5-(trifluoromethyl)aniline

A bidentate NO donor Schiff base, 2-(((2-chloro-5- (trifluoromethyl)phenyl)imino)methyl) phenol ( HL ¹ ) and its complexes [Co(L¹)₂(H₂O)₂] ( 1 ), [Cu(L¹)₂] ( 2 ), [Mn(L¹)₂(H₂O)₂] ( 3 ), [Ni(L¹)₂(H₂O)₂] ( 4 ), [Pd₂(L¹)₂(OAc)₂·1.16H₂O] ( 5 ), [Pt(L¹)₂] ( 6 ) were synthesized and characterized by different physico-chemical techniques including elemental and thermal analysis, magnetic susceptibility measurements, molar electric conductivity, IR, ¹H-NMR, ¹³C-NMR, UV–Vis, mass spectroscopies and X-ray powder diffraction (XRD). The molecular structures of ligand HL ¹ and two complexes ( 2 and 5 ) were confirmed by X-ray crystallography analysis on the monocrystal. In this complexes, the metal ions are in distorted square-planar environments. The copper (II) complex is mononuclear and crystallized in a monoclinic space group P21/c, whereas palladium (II) complex is dinuclear and crystallized in the trigonal crystal system R-3. The toxicity of the ligand and complexes was evaluated on both plant and animal cells, using the plant species Triticum aestivum L. and the crustacean Artemia franciscana Kellogg. At concentrations up to 100 μM the compounds presented very little toxicity on Artemia franciscana Kellogg. Moreover, the palladium (II) complex was devoid of any toxicity on the plant cells.     

Homogenization of integrals with pointwise gradient constraints via the periodic unfolding method

Abstract The pointwise gradient constrained homogenization process, for Neumann and Dirichlet type problems, is analyzed by means of the periodic unfolding method recently introduced in [21]. Classically, the proof of the homogenization formula in presence of pointwise gradient constraints relies on elaborated measure theoretic arguments. The one proposed here is elementary: it is based on weak convergence arguments in L^p spaces, coupled with suitable regularization techniques. Keywords: Homogenization, Gradient constrained problems, Periodic unfolding method Mathematics Subject Classification (2000): 49J45, 35B27, 74Q05     

Moment sequences for ultradistributions

Supported by DAAD, West Germany     

A time dependent coupled system related to the tridimensional equations of a nematic liquid crystal

In this paper we prove some results about the existence, uniqueness and regularity of the solutions of a tridimensional variational approximated model for the Leslie's equations of an incompressible nematic liquid crystal (cf. [7]). This model was introduced in [1] where the bidimensional case is studied. Here we use the methods developed in [6], [4] and [8].     

Identification and specificity profiling of protein prenyltransferase inhibitors using new fluorescent phosphoisoprenoids

Posttranslational modification of proteins with farnesyl and geranylgeranyl isoprenoids is a widespread phenomenon in eukaryotic organisms. Isoprenylation is conferred by three protein prenyltransferases: farnesyl transferase (FTase), geranylgeranyl transferase type-I (GGTase-I), and Rab geranylgeranyltransferase (RabGGTase). Inhibitors of these enzymes have emerged as promising therapeutic compounds for treatment of cancer, viral and parasite originated diseases, as well as osteoporosis. However, no generic nonradioactive protein prenyltransferase assay has been reported to date, complicating identification of enzyme-specific inhibitors. We have addressed this issue by developing two fluorescent analogues of farnesyl and geranylgeranyl pyrophosphates {3,7-dimethyl-8-(7-nitro-benzo[1,2,5]oxadiazol-4-ylamino)-octa-2,6-diene-1}pyrophosphate (NBD-GPP) and {3,7,11-trimethyl-12-(7-nitro-benzo[1,2,5]oxadiazo-4-ylamino)-dodeca-2,6,10-trien-1} pyrophosphate (NBD-FPP), respectively. We demonstrate that these compounds can serve as efficient lipid donors for prenyltransferases. Using these fluorescent lipids, we have developed two simple (SDS-PAGE and bead-based) in vitro prenylation assays applicable to all prenyltransferases. Using the SDS-PAGE assay, we found that, in contrast to previous reports, the tyrosine phosphatase PRL-3 may possibly be a dual substrate for both FTase and GGTase-I. The on-bead prenylation assay was used to identify prenyltransferase inhibitors that displayed nanomolar affinity for RabGGTase and FTase. Detailed analysis of the two inhibitors revealed a complex inhibition mechanism in which their association with the peptide binding site of the enzyme reduces the enzyme's affinity for lipid and peptide substrates without competing directly with their binding. Finally, we demonstrate that the developed fluorescent isoprenoids can directly and efficiently penetrate into mammalian cells and be incorporated in vivo into small GTPases.     

A Fluorescence Emission, FT-IR and UV-VIS Absorption Study of the Some Uranium (VI) Schiff Bases Complexes

The capacity of metallic ions to form complexes depends on the electric charge and its mass and on the ligands nature. In this study we followed the coordination capacity of the uranyl ion (UO2(2+)) with a series of Schiff bases. The Schiff bases have been obtained through the condensation of some salicylic aldehyde derivates with a series of diamines. As a result of the reaction between these substances and the uranyl ions the mono-, bi-, or poly-nuclear complexes, depend on the nature of the ligands. The forming of the complexes is highlighted through ultraviolet-visible, Fourier transform infrared (IR), and fluorescence spectroscopy. In the IR studies the forming of the complexes is highlighted by the apparition of a new band at approximately 920 cm(-1,) characteristic to the O=U=O group. Also modifications of valence vibrations appear characteristic to the azomethinic groups, nu(C=N,) and the apparition of some new bands in the 300-500 cm(-1) domain, characteristic to forming of some new bonds U-O and U-N. The formed complexes represent tetragonal bipyramidal geometry. The study of the capacity coordination of uranyl ions is important in determining, dozing and precipitin of the ions in diverse used waters.