To provide a fluorinated ether compound, a fluorinated ether composition and a coating liquid that are able to form a surface layer which is excellent in water/oil repellency, abrasion resistance, fingerprint stain removability, lubricity and outer appearance, and an article having such a surface layer. A fluorinated ether compound represented by A.sup.1O(R.sup.f1O).sub.m1-Q.sup.1[C(O)N(R.sup.1)].sub.p1R.sup.11C[R.sup.12SiR.sup.13.sub.n1X.sup.1.sub.3-n1].sub.3, wherein A.sup.1 is a C.sub.1-20 perfluoroalkyl group; R.sup.f1 is a fluoroalkylene group having no branched structure; ml is an integer from 2 to 210; Q.sup.1 is a single bond or a fluoroalkylene group having no branched structure; R.sup.1 is a hydrogen atom, etc.; p1 is 0 or 1; R.sup.11 is a single bond, an alkylene group, etc.; R.sup.12 is an alkylene group, etc.; R.sup.13 is a monovalent hydrocarbon group, etc.; X.sup.1 is a hydrolyzable group; and n1 is an integer of from 0 to 2.

To provide a fluorinated ether compound, a fluorinated ether composition and a coating liquid that are able to form a surface layer which is excellent in water/oil repellency, abrasion resistance, fingerprint stain removability, lubricity and outer appearance, and an article having such a surface layer. A fluorinated ether compound represented by A.sup.1O(R.sup.f1O).sub.m1-Q.sup.1[C(O)N(R.sup.1)].sub.p1R.sup.11C[R.sup.12SiR.sup.13.sub.n1X.sup.1.sub.3-n1].sub.3, wherein A.sup.1 is a C.sub.1-20 perfluoroalkyl group; R.sup.f1 is a fluoroalkylene group having no branched structure; ml is an integer from 2 to 210; Q.sup.1 is a single bond or a fluoroalkylene group having no branched structure; R.sup.1 is a hydrogen atom, etc.; p1 is 0 or 1; R.sup.11 is a single bond, an alkylene group, etc.; R.sup.12 is an alkylene group, etc.; R.sup.13 is a monovalent hydrocarbon group, etc.; X.sup.1 is a hydrolyzable group; and n1 is an integer of from 0 to 2.

The present invention provides a polyrotaxane having high durability and in particular, high hydrolysis resistance, and a method for producing said polyrotaxane. The present invention provides a polyrotaxane obtained by disposing blocking groups on both ends of a pseudopolyrotaxane so that an annular molecule cannot be displaced, said pseudopolyrotaxane being obtained by forming a clathrate by piercing the opening of the cyclic molecule with a linear molecule, said polyrotaxane being characterized in that the cyclic molecule has a substituent represented by formula I (in formula I, R.sub.1 represents a group such as CH.sub.3 and CH.sub.2CH.sub.3, R.sub.2 represents H or a group such as CH.sub.3, and n is the apparent degree of polymerization of a polyalkylene oxide chain or a derivative thereof added to the cyclic molecule, the value of n being 1.1 to 10.0).

The present invention is directed to branched reactive water-soluble polymers comprising at least two polymer arms, such as poly(ethylene glycol), attached to a central aliphatic hydrocarbon core molecule through heteroatom linkages. The branched polymers bear at least one functional group for reacting with a biologically active agent to form a biologically active conjugate. The functional group of the branched polymer can be directly attached to the aliphatic hydrocarbon core or via an intervening linkage, such as a heteroatom, -alkylene-, O-alkylene-O, -alkylene-O-alkylene-, -aryl-O, O-aryl-, (O-alkylene-).sub.m, or (-alkylene-O).sub.m linkage, wherein m is 1-10.

The present invention is directed to branched reactive water-soluble polymers comprising at least two polymer arms, such as poly(ethylene glycol), attached to a central aliphatic hydrocarbon core molecule through heteroatom linkages. The branched polymers bear at least one functional group for reacting with a biologically active agent to form a biologically active conjugate. The functional group of the branched polymer can be directly attached to the aliphatic hydrocarbon core or via an intervening linkage, such as a heteroatom, -alkylene-, O-alkylene-O, -alkylene-O-alkylene-, -aryl-O, O-aryl-, (O-alkylene-).sub.m, or (-alkylene-O).sub.m linkage, wherein m is 1-10.

To provide a fluorinated ether compound, a fluorinated ether composition and a coating liquid that are able to form a surface layer which is excellent in water/oil repellency, abrasion resistance, fingerprint stain removability, lubricity and outer appearance, and an article having such a surface layer. A fluorinated ether compound represented by A.sup.1-O(R.sup.f1O).sub.m1-Q.sup.1-[C(O)N(R.sup.1)].sub.p1R.sup.11C[R.sup.12SiR.sup.13.sub.n1X.sup.1.sub.3-n1].sub.3, wherein A.sup.1 is a C.sub.1-20 perfluoroalkyl group; R.sup.f1 is a fluoroalkylene group having no branched structure; m1 is an integer from 2 to 210; Q.sup.1 is a single bond or a fluoroalkylene group having no branched structure; R.sup.1 is a hydrogen atom, etc.; p1 is 0 or 1; R.sup.11 is a single bond, an alkylene group, etc.; R.sup.12 is an alkylene group, etc.; R.sup.13 is a monovalent hydrocarbon group, etc.; X.sup.1 is a hydrolyzable group; and n1 is an integer of from 0 to 2.

[Problem] To provide a gel which can be produced in a short time, has controlled properties such as modulus and expansion pressure, and has a low polymer concentration. [Solution] A process for producing a polymer gel in which gel-precursor clusters have been crosslinked with one another to form a three-dimensional network structure, characterized by comprising a) a step in which monomer or polymer units that are present in a concentration less than a critical gelation concentration are crosslinked to form the gel-precursor clusters, the gel-precursor clusters having a storage modulus G and a loss modulus G which satisfy the relationship G<G, and b) a step in which the gel-precursor clusters are crosslinked with one another by a crosslinking agent to obtain a gel having a three-dimensional network structure.

An encoding/decoding apparatus and method using a low-density parity-check code (LDPC code) is disclosed. Basic column group information, serving as a set of information regarding positions of rows with weight 1, is extracted from a reference column in each column group of a predetermined parity-check matrix. Column group information transforms the positions of rows with weight 1 into positions whose lengths are within a required parity length. A parity-check matrix is generated according to the generated column group information. Data is enclosed or decoded based on the generated parity-check matrix.

An encoding/decoding apparatus and method using a low-density parity-check code (LDPC code) is disclosed. Basic column group information, serving as a set of information regarding positions of rows with weight 1, is extracted from a reference column in each column group of a predetermined parity-check matrix. Column group information transforms the positions of rows with weight 1 into positions whose lengths are within a required parity length. A parity-check matrix is generated according to the generated column group information. Data is enclosed or decoded based on the generated parity-check matrix.

Disclosed is a multi-arm targeting drug conjugate modified by a water-soluble polymer; the drug conjugate has the structural formula of (III). In formula (III), R is an organic core, POLY is a polymer, L is a multivalent linker, T is a targeting molecule, D is a camptothecin-based drug, and q is any integer between 3 and 8. The drug conjugate may improve the poor water solubility, high toxicity and low bioavailability of camptothecin-based drugs.