Abstract: This invention relates to chemical products of general formula ##STR1## wherein R is an amino group, mono or bi-hydroxyalkyl substituted, or a thio group, mono hydroxyalkyl substituted, in which one or more of the available --OH groups have been esterified with acids containing 2 to 18 carbon atoms.It is also described a process for the preparation of said products, which comprises reacting a corresponding starting compound, N or S-hydroxyalkyl substituted, with the chloride or the anhydride of the acid concerned.

Abstract: Cardiac valvular prosthesis of mechanical type consisting of a sewing ring welded to a housing orifice where, in the absence of pins or hinges, two leaflets, preferably provided with a slight curvature, are free of moving with both rotation and translation movement. This is achieved through suitable metal structures, able both to permit the correct opening and closing of the leaflets (i.e. to act as rotation fulcrum) and to guarantee the guidance and the right positioning of the leaflets (i.e. to exert a constraint).The "rotation fulcrum" and the "constraint" structures can be separated and independent, or can form part of one structure devoid of discontinuity; this latter case is shown in FIGS. 3 and 4 of the drawing. The leaflet thickness can also not be uniform, as well as the profiles of the two sides of each leaflet can be different.

Abstract: This invention relates to a process for the preparation of D(-) mandelic acid by the acid hydrolysis of the corresponding carbamate in an aqueous environment at a temperature of between 40.degree. and 100.degree. C. and at a pH of between 1 and 3.5.The invention also relates to a process for the enzymatic hydrolysis of racemic 5-substituted 2,4-oxazolidinediones to give only one of the two possible optical isomers, i.e., the D-carbamyl-.alpha.-hydroxy acid. The free D-.alpha.-hydroxy acid can be obtained from the optically active carbamyl derivative by simple hydrolysis. Of particular interest is the case in which the D-.alpha.-hydroxy acid is D(-)mandelic acid. The enzymatic activity required for preparing the carbamyl derivative of D(-)mandelic acid has been found both in homogenised veal liver and in a series of microorganisms, including Agrobacterium radiobacter, Bacillus brevis, Bacillus stearothermophilus, Pseudomonas sp., Pseudomonas desmolytica, Pseudomonas fluorescens, Pseudomonas putida.

Abstract: A prosthetic polymer material is made non-thrombogenic by immobilizing apyrase on its surface. Immobilization is preferably carried out by hydrolytically activating the surface of a polyamide polymer or a polyethylene terphthalate polymer, and treating the hydrolyzed polymer with a solution of cross-linking agent and a solution of apyrase. The apyrase converts adenosine diphosphate to adenosine monophosphate and adenosine whereby the formation of thrombi is inhibited.

Abstract: Fibres for biological uses can be produced by adding to a spinnable solution of a polymer selected from among many of the most common polymers and copolymers, a substance selected from among anti-platelet aggregation substances, anticoagulants and substances having a similar action. The substances can also be applied as a surface outer layer to articles made with the polymeric substances.

Abstract: Polyamide materials for the construction of protheses and surgical sundries are made biocompatible by inducing a superficial hydrolysis by treating such materials, either raw or in the form of shaped articles, with a normal multiple solution of hydrogen chloride. Thrice normal or fourfold normal solutions are preferred and the treatment time being a function of the temperature. At human body temperature (37.degree. C.) a treatment time from 30 to 60 minutes will do.

Abstract: This invention relates to a process for preparing carbamyl derivatives of .alpha.-hydroxy acids by the hydrolysis of 5-substituted 2,4-oxazolidinediones.The carbamyl derivatives can be further hydrolyzed to .alpha.-hydroxy acids.The invention also relates to a process for the enzymatic hydrolysis of racemic 5-substituted 2,4-oxazolidinediones to give only one of the two possible optical isomers, i.e. the D-carbamyl-.alpha.-hydroxy acid. The free D-.alpha.-hydroxy acid can be obtained from the optically active carbamyl derivative by simple hydrolysis. Of particular interest is the case in which the D-.alpha.-hydroxy acid is D(-)mandelic acid. The enzymatic activity required for preparing the carbamyl derivative of D(-)mandelic acid has been found both in homogenized veal liver and in a series of microorganisms, including Agrobacterium radiobacter, Bacillus brevis, Bacillus stearothermophilus, Pseudomonas sp., Pseudomonas desmolytica, Pseudomonas fluorescens, Pseudomonas putida.

Abstract: For the asymmetrical hydrogenation of prochiral olefins, a catalyst system is proposed which is a Rhodium cationic complex immobilized on a clay-like mineral such as hectorite, bentonite and haloysite.

Abstract: A method is disclosed for embedding sequestering agents in filamentary structures, the method comprising the steps of preparing an emulsion formed by an aqueous or nearly aqueous solution of the sequestering agent and a solution of the filament-forming polymer in an appropriate solvent, and spinning the emulsion in a coagulation bath.

Abstract: A composition for the purification of blood in which impurities of the mercaptan class are present is disclosed, such composition being occluded in fibrous materials and consisting of a polymer functionalized with an organic mercury compound or with an anhydride of an organic acid. As the functionalizing compounds parachloromercury aniline, parachloromercurybenzoic acid and maleic anhydride are preferred.

Abstract: Phenylalanine level in blood or another medium is considerably reduced and can even be annulled by causing blood or the other medium to flow through a mass of porous fibers in which the enzyme phenylalanine ammonia lyase has been occluded: the fibers have been previously made biocompatible, if necessary.

Abstract: Biocompatible articles are obtained by treating a polymeric material with a hydrolyzing agent on its surface and covalently binding thereon a biological agent, such as an anti-platelet-aggregation agent.

Abstract: A method is disclosed for improving the activity of oxireductase enzymes, the improvement consisting in that an enzyme and a previously functionalized coenzyme are embedded in a filamentary structure, the coenzyme having previously been attached to a water-soluble, high-molecular-weight polymer.

Abstract: Polymers of the type commonly used in packaging are rendered degradable through the action of sunlight by adding thereto up to 3% of an olefinically unsaturated compound containing at least two double bonds, such as 1,6-diphenylhexatriene.

Abstract: A macromolecular adenine derivative containing at least one unity having the general formula: ##STR1## wherein, n is 1, 2, 3 or 4; the radical: ##STR2## is derived from an adenine derivative wherein the amino group in position 6 in the adenine nucleus is functional; and the nitrogen atom, N<, belongs to a macromolecular compound containing one or more primary or secondary amine groups, is prepared by condensing the functional adenine derivative with a polymer containing one or more primary or secondary amine groups in the presence of a carbodiimide. These compounds are useful in affinity chromatographies or as unspreading co-enzymes.

Abstract: A method is disclosed, for depolluting fresh and sea waters from hydrocarbonaceous pollutants, the improvement consisting in that the usual microorganism cultures used for oxidizing the hydrocarbons are integrated by lipophilic and floating compounds which contain slow-release nitrogen in a form which can be assimilated by such micro-organisms. Ureidic derivatives of higher aldehydes are the preferred compounds. Inert supports can be used, if necessary, and still better results are achieved when using also nonionic dispersants and freeze-dried hydrocarbon-oxidizing microorganisms.

Abstract: A prochiral or racemic substrate such as a prochiral ketone is converted into an optically active product through a process wherein said substrate is subjected to an asymmetric hydrogen transfer reaction by means of an optically active amino-alane or polyimino-alane represented by the formulaH.sub.2 AlNR.sub.1 R.sub.2, H Al(NR.sub.1 R.sub.2).sub.2 or (H AlNR).sub.nwherein R, R.sub.1 and R.sub.2 are alkyl, aryl or cycloalkyl radicals, n is an integer higher than 4, and which contains an Al -- N direct bond and an Al -- H bond per aluminum atom, and the third substituent bound to aluminum is halogen, --H, ##STR1## or --OR wherein R has the aforesaid meaning, and wherein the asymmetry center is constituted by a primary or secondary amine group containing an optically active alkyl radical.

Abstract: Oily hydrocarbons which pollute the surface of water are removed therefrom by scattering over the polluted surface solid particles of nutrient salt containing nitrogen and phosphorous in a form that is readily assimilable by aqueous microorganisms capable of metabolizing hydrocarbons. The particles of nutrient salt are given a surface pretreatment with paraffine so that they are buoyant and only slowly soluble in water and lipophilic.

Abstract: A plastic material such as a polyethylene which is adapted for use in packaging is rendered photodegradable under the direct action of sunlight by mixing therewith an amount, up to 3% by weight, of an additive consisting of 1.2.4.5 tetramethylbenzene.

Abstract: A novel process for making polymers degradable by the direct action of sunlight is disclosed. The process is based on the addition to the polymer of a compound having the formula: ##EQU1## in which R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same or different and are selected from the group consisting of aromatic radicals with the proviso that one or two of them may be selected from the group consisting of hydrogen, alkyl, cycloalkyl and arylalkyl.