Abstract: The invention concerns delivery particles (DP's) for active principles (AP's) based on linear amphiphilic polyamino-acids (PAA's), with &agr;-peptide chains, capable of being spontaneously formed by contacting PAA's with a liquid medium, preferably with water, wherein the hydrophile part of the PAA's is solubilized more than the hydrophobic parts of said PAA's, such that the latter precipitate while being organised in discrete supra-molecular arrangements, of average size ranging between 0.01 and 20 &mgr;m, capable of combining with at least an AP and releasing the latter in vivo, in prolonged and controlled manner.

Abstract: Novel spiropyran compounds, particularly with photochromic properties, are disclosed, as well as photochromic compositions and ophthalmic articles containing said compounds. The photochromes have been designed so as to have a high colorability, a high sensitivity to activating radiation breaking the pyran ring, to be entirely or practically free from coloration in a non activated non exposed state, to have an intense coloration following activation and a high coverage of the visible spectrum in combination with at least one other photochrome, and to have high rates of coloration/decoloration. The spiropyrans are easily produced and photochemically stable, and are, e.g., of formula (i), wherein L=(a); (b).

Abstract: Novel spiropyran compounds, particularly with photochromic properties, are disclosed, as well as photochromic compositions and ophthalmic articles (e.g. lenses) containing said compounds. The photochromes have been designed so as to have a high colorability, a high sensitivity to activating radiation breaking the pyran ring, to be entirely or practically free from coloration in a non activated (non exposed) state, to have an intense coloration following activation and a high coverage of the visible spectrum in combination with at least one other photochrome, and to have high rates of coloration/decoloration. The spiropyrans are easily produced and photochemically stable, and are, e.g., of formula (i), wherein L=(a);(b).

Abstract: The present invention relates to microcapsules for the oral administration of medicinal and/or nutritional active principles (AP), which are smaller than or equal to 1000 .mu.m in size. These microcapsules consist of particles which are coated with a coating material consisting of a mixture of a film-forming polymer derivative, a hydrophobic plasticizer, a functional agent and a nitrogen-containing polymer. These microcapsules are also characterized by their ability to remain in the small intestine for a long time (at least 5 hours) and to allow, during the residence, release and absorption of the AP. The invention also relates to a process for the production of the said microcapsules.

Abstract: The present invention relates to an aerosol composition for forming a preferably hydrated membrane which after vaporizing comprises as least one hydrophobic phase containing at least one film-forming polymer at least partly solubilized in an organic solvent system. The polymer is selected from hydrophobic polyaminoacids, preferably from the polyaminoacids obtained from at least one of the amino acids alanine, valine, leucine, isoleucine, proline, methionine, phenylalanine, tryptophan, aspartic and glutamic acid esters, or the derivatives thereof. The compositions also comprises as least one hydrophilic phase, and at least one propellant. The preferably hydrated membrane formed by vaporizing this composition, the application of the composition and of the preferably hydrated membrane as a dressing, are also disclosed.

Abstract: The present invention relates to delivery vehicles which are useful for the administration of active principles (APs), preferably medicinal or nutritional active principles, in particular via the oral or parenteral route.The technical problem solved by the invention is that which consists in providing delivery vehicles composed of (nano)- or (micro)particles based on polyamino acids, and which are invert with respect to the AP (proteins), of controllable particle size, strong and inexpensive.According to the invention, the particles have an average size of less than 200 .mu.m and consist of a polyamino acid of the Leu/Glu type, in which Leu/Glu+Leu.gtoreq.3% and the M.sub.w .gtoreq.4,000 D.

Abstract: The present invention relates to a method for the preparation of polyamino acids, with controlled molecular weights, by polymerization of N-carboxyanhydrides (NCAs) of at least one amino acid, using at least one initiator of the strong base type and in liquid medium, characterized in that it consists in including, in the liquid reaction medium, given amounts of water and/or of alcohol. Application: synthesis of polyamino acids with mechanical and rheological characteristics adapted to applications as biomaterials.

Abstract: The present invention relates to a modified collagen which is soluble in water and/or in aprotic polar organic solvents and which comprises free or substituted thiol functional groups carried by residues of cysteine or its derivatives, the residues being, at least partially, residues which are directly grafted onto the collagen chain, characterized in that it possesses a level of free or substituted thiol functional groups greater than 0.3, preferably 0.5 mM/g of collagen. The invention also relates to the production of these new collagen derivatives and to their application in the preparation of biomaterials, it being possible for the latter to be used especially in the manufacture of implants, prostheses or the like.

Abstract: The present invention relates to novel organic products resulting, for example, from the condensation of a dicarboxylic acid with a sulfur-containing amino acid or one of its derivatives. These products contain reactive thiol SH functions which can be oxidized to form disulfide bridges, resulting in polymers, which may or may not be crosslinked.These novel organic products correspond to the following formula: ##STR1## The invention also relates to the polymers and/or networks deriving from the products of formula (I) and to one of the methods for obtaining these products and their derivatives.Applications as biomaterials: sutures, ligatures, prostheses, adhesives or systems for the controlled release of active principles.

Abstract: Novel nonlinearly optically active compound's, well suited for electrooptical applications, have the following general formulae: ##STR1## wherein D is an electron donor group; A and A.sub.1, which may be identical or different, are each an electron acceptor group; and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each a lower alkyl radical or a hydrogen atom.

Abstract: Novel nonlinearly optically active compounds, well suited for electrooptical applications, have the following general formulae: ##STR1## wherein D is an electron donor group; A and A.sub.1, which may be identical or different, are each an electron acceptor group; and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each a lower alkyl radical or a hydrogen atom.

Abstract: Novel organosilicon compounds having a second order hyperpolarizability coefficient .beta. greater than zero, well suited for use in the field of nonlinear optics, e.g., in telecommunication devices, have the general formula: ##STR1## which n is an integer ranging from 1 to 20; R.sub.1 is an electron donating group; R.sub.2 is an electron accepting group; R.sub.3 is an alkyl radical having from 1 to 8 carbon atoms, a hydrogen atom, an aryl radical, or an R.sub.1 or R.sub.2 radical; and R.sub.4 is an alkyl radical having from 1 to 8 carbon atoms, a hydrogen atom, an aryl radical, or an R.sub.1 radical when R.sub.3 is not an R.sub.2 radical or an R.sub.2 radical when R.sub.3 is not an R.sub.1 radical.

Abstract: Hydrogenated silanes are facilely prepared by redistribution, by reacting (1) a silane having the formula H.sub.m SiX.sub.4-m in which X is halogen or an alkoxy group and m is an integer equal to 0, 1, 2 or 3, with (2) an alkyl or aryl hydrosilane having the formula R.sub.n H.sub.p SiX'.sub.4-(n+p) in which X' is halogen or an alkoxy group, R is an alkyl or aryl group and n and p, which may be identical or different, are integers equal to 1, 2 or 3, with the proviso that n+p.ltoreq.4, in the presence of (3) a catalytically effective amount of a catalyst comprising (i) a quaternary ammonium salt having the formula R'.sub.4 NY or a quaternary phosphonium salt having the formula R'.sub.

Abstract: Elastomer/filler interface agents for filled vulcanizable matrices, e.g., natural or synthetic rubber, comprise the amido reaction products of tetraethylene pentamine ("TEPA") with amide-forming organosulfur compounds.

Abstract: Gelation-resistant, high pot life organopolysiloxane compositions adapted for antiadhesive/release coating applications, are comprised of (1) at least one substantially straight-chain organopolysiloxane having a viscosity ranging from about 50 to 100,000 mPa.s at 25.degree. C. and containing at least x alkenyl unsaturated hydrocarbon groups bonded to a silicon atom, per molecule, wherein x.gtoreq.2, (2) at least one organohydropolysiloxane crosslinking agent having a viscosity ranging from about 10 to 100,000 mPa.s at 25.degree. C. and containing at least y hydrogen atoms bonded to silicon atoms, per molecule, wherein y.gtoreq.2, (3) a catalytically effective amount of a platinum group metal crosslinking catalyst, and (4) an effective amount of at least one azodicarboxylate gelation inhibitor which is inert to the activity of said catalyst (3), but in insufficient amount as to prevent the crosslinking of said polysiloxanes (1) and (2) under crosslinking conditions.

Abstract: Hydrogenosilanes, notably the monosilanes, are conveniently prepared by reducing a halogenosilane with an alkali or alkaline earth metal hydride, typically in a solvent reaction medium, in the presence of a catalytically effective amount of a sequestering agent having the general formula: ##STR1##

Abstract: Polychlorobenzenes are isomerized/rearranged, by reacting (i) at least one tetrachlorobenzene, or at least one tetrachlorobenzene in admixture with at least one trichlorobenzene, pentachlorobenzene and/or hexachlorobenzene, or (ii) pentachlorobenzene, or pentachlorobenzene in admixture with at least one trichlorobenzene and/or hexachlorobenzene, or (iii) hexachlorobenzene, or hexachlorobenzene in admixture with at least one trichlorobenzene and/or dichlorobenzene, with at least one alkali metal amide, or at least one alkali metal alcoholate, or admixture thereof, said reaction being conducted in the presence of an agent which complexes the cation of the amide, alcoholate, or admixture thereof.

Abstract: Silane, well adopted as a source of semiconductor/photovoltaic grade silicon, is facilely prepared from methyldichlorosilane and trichlorosilane and/or tetrachlorosilane by, (A) in a first step catalytically redistributing methyldichlorosilane with trichlorosilane or tetrachlorosilane, or admixture thereof, to form methyltrichlorosilane and dichlorosilane, and separating dichlorosilane from the resulting reaction medium, and (B) in a second step, catalytically disproportionating the dichlorosilane thus separated to form silane and trichlorosilane, and thence recovering silane thus formed and optionally recycling trichlorosilane to said step (A).

Abstract: The organosilanes/organopolysilanes, e.g., methylchlorosilanes useful in the production of silicones, are facilely prepared by contacting, in an inert atmosphere, (1) at least one disilane having the general formula:(R).sub.3 Si--Si--R).sub.3 (I)wherein the radicals R, which may be identical or different, are each C.sub.1 -C.sub.6 alkyl, hydrogen, 3,3,3-trifluoropropyl, trimethylsiloxy, fluorine, chlorine, bromine or iodine, with (2) a catalytically effective amount of a catalyst system comprising (a) at least one ionic inorganic salt having the formula:M.sup.+ A.sup.-wherein M.sup.+ is lithium, sodium, potassium, rubidium or cesium, and A.sup.- is fluoride, chloride, bromide or iodide, and (b) at least one compound which complexes the cation M.sup.+ of said salt (a), e.g., a sequestering agent having the formula:N--CHR.sub.1 --CHR.sub.2 O--CHR.sub.3 CHR.sub.4 O).sub.n R.sub.5 ].sub.3 (II).

Abstract: Hydrogenosilanes are facilely prepared by redistribution, by reacting (1) a silane having the formula H.sub.m SiX.sub.4-m in which X is halogen or an alkoxy group and m is an integer equal to 0, 1, 2, or 3, with (2) an alkyl or aryl hydrogenosilane having the formula R.sub.n H.sub.p SiX'.sub.4-(n+p) in which X' is halogen or an alkoxy group, R is at least one alkyl or aryl group, which may be identical or different, and n and p, which may be identical or different, are integers equal to 1, 2 or 3, with the proviso that n+p.ltoreq.4, in the presence of (3) a catalytically effective amount of a catalyst system which comprises (i) at least one ionic inorganic salt having the formula M.sup.+ A.sup.- and (ii) a compound which complexes the M.sup.+ cation of said salt (i) and at least partially solubilizes and dissociates same in the medium of reaction.