Abstract: Described herein are injectable in vivo crosslinking materials for use as soft tissue filler comprising (a) a reactive multi-arm polymer that comprises a plurality of hydrophilic polymeric arms, at least a portion of the hydrophilic polymeric arms comprising one or more reactive end groups and (b) a multifunctional compound that comprises functional groups that are reactive with the reactive end groups of the reactive multi-arm polymer. Also described herein are systems and methods that are based on such materials.

Abstract: The present invention relates to a tetramethylbiphenol epoxy resin represented by the following formula (1), which is an epoxy resin having excellent solvent solubility, a small hydrolyzable chlorine amount and further an appropriate melt viscosity and being effectively applicable, to a semiconductor sealing material and electrical or electronic components such as laminate sheet: wherein n represents an integer of 0 to 10.

Abstract: This invention relates to polycarbonate compositions and articles comprising the same. The polycarbonate compositions comprise the following components: A) from 75 wt.-% to 97.5 wt.-% of a polycarbonate, B) from 1.5 wt.-% to 15 wt.-% of a flow promoter selected from alicyclic hydrocarbon resins, and C) from 1 wt.-% to 15 wt.-% of an impact modifier, in each case based on the total weight of the composition; wherein the composition comprises no polycarbonate-polysiloxane copolymer. The polycarbonate compositions of the present invention have good coating resistance, chemical resistance and impact properties as well as better flowability.

Abstract: Techniques regarding the synthesis of one or more polymers through one or more ring-opening polymerizations conducted within a flow reactor and facilitated by one or more anionic catalysts are provided. For example, one or more embodiments can comprise a method, which can comprise functionalizing, via a post-polymerization reaction within a flow reactor, a chemical compound by covalently bonding a trimethylsilyl protected thiol to a pendent functional group of the chemical compound in a presence of a catalyst. The pendent functional group can comprise a perfluoroaryl group and a methylene group.

Abstract: A disk reactor for production of polycarbonate includes a cylinder provided with an end cover at each end. The cylinder is provided with a material inlet, a product outlet and a gas phase port thereon. The cylinder is provided with a driving shaft therein. The driving shaft is provided with plural disks at different spaces thereon. Each disk has slope different from each other. Each disk is provided with plural transverse blades and plural transverse scrapers thereon. A scraper blade is arranged between two disks and fixed on the driving shaft. Compared with the prior disk reactors, the disk reactor fully considers the change of melt viscosity in the polymerization process, simultaneously increases the mass transfer area of the reactor, has good film forming and surface renew performance and high light component removal efficiency, and can produce polycarbonate with high molecular weight and uniform quality.

Abstract: A block copolymer includes a water-soluble block that is bonded to one or more hydrophobic polycarbonate blocks that include pendant fluoroaryl substituents.

Abstract: A polyacetal resin composition which is suppressed low in formaldehyde generation, while having high stiffness and high toughness. The resin is produced by a method including blending from 0.1 part by weight to 2 parts by weight (inclusive) of a polyacetal copolymer having a branched or crosslinked structure, which is a copolymer of a trioxane, a compound having from 3 to 4 (inclusive) cyclic ether units in each molecule and a compound having one cyclic ether unit in each molecule, per 100 parts by weight of a linear polyacetal copolymer which contains an oxymethylene unit as a main constituent, while containing, as a comonomer unit, an oxyalkylene unit at a ratio of from 0.4% by mole to 0.9% by mole (inclusive) relative to the constituents of the linear polyacetal copolymer, the linear polyacetal copolymer being obtained by copolymerization wherein a heteropolyacid or the like is used as a polymerization catalyst.

Abstract: The present invention relates to a polycarbonate resin composition including both of silicone oil and olefin-based wax at a proper ratio and thus having improved dispersibility of titanium dioxide in the composition as well as high impact strength and melt index (moldability), and also relates to a polycarbonate molded article made of the polycarbonate resin composition. The polycarbonate resin composition according to the present invention includes silicone oil and olefin-based wax at a proper ratio and thus improves dispersibility of titanium dioxide which is added to the composition to give whiteness, while preserving high impact strength and melt index (moldability), so that crawling which is generated on the surface of a final product of polycarbonate molded article is prevented and the appearance property of the molded article is improved.

Abstract: This invention provides a novel method for producing a lactide-lactone copolymer. The method is characterized by copolymerizing a lactide and a lactone using a molybdenum compound as a catalyst.

Abstract: A polycarbonate resin composition includes: (D) about 1 to about 10 parts by weight of a silicon-based resin; (E) about 1 to about 10 parts by weight of a core-shell graft copolymer; and (F) about 1 to about 20 parts by weight of a flame retardant, with respect to about 100 parts by weight of a base resin including: (A) about 70 to about 90 wt % of a polycarbonate resin; (B) about 9 to about 25 wt % of a polysiloxane-polycarbonate copolymer; and (C) about 1 to about 10 wt % of an aromatic vinyl-based graft copolymer. The polycarbonate resin composition can have improved releaseability and external appearance, and excellent impact strength and coloring.

Abstract: Disclosed are polyvalent macromolecules, compositions comprising the macromolecules, and methods of use. The polyvalent macromolecules have a polymer backbone and pendent groups attached to the polymer backbone. Some or all of the pendent groups have optionally a linker, a surface-seeking group capable of binding strongly to a metal surface, and a spectroscopically detectable chromophore detectable.

Abstract: A macrocycle based on ?-diketimines, a process for preparing the inventive macrocycle, an uncharged macrocyclic dimetallic complex based on the inventive macrocycle, and a process for preparing the uncharged macrocyclic dimetallic complex, the use of the uncharged macrocyclic dimetallic complex as a polymerization catalyst in the polymerization of carbon dioxide with one or more epoxides, a process for preparing polycarbonates by reacting carbon dioxide with one or more epoxides in the presence of the inventive uncharged macrocyclic dimetallic complex, and a polycarbonate prepared by the process according to the invention.

Abstract: It is an object of the present invention to obtain an optically transparent nano-dispersed polymer blend extrudate and a transparent resin having a microscopic dispersion structure in which incompatible polymer blend is melted and kneaded, one of resins is formed into a matrix, a size of dispersed phase of the other resin is controlled to 300 nm or less, more preferably 100 nm or less. Extra additive such as a compatibilizer is not added. When the incompatible polymer blend is melted and kneaded using a high shearing and forming apparatus having an inner feedback type screw under a condition that the screw rotation speed is 600 rpm to 3000 rpm, the rotation speed of the inner feedback type screw is increased, the kneading time is set under constant rotation speed, the high shearing forming condition is adjusted, and a structure in which a size of dispersed phase is controlled to 300 nm or less, more preferably 100 nm or less is formed.

Abstract: An antimicrobial silicone rubber comprises a silicone rubber substrate, a catechol layer bound to a surface of the silicone rubber substrate, and an antimicrobial layer disposed on the catechol layer. The catechol layer comprises a catechol material, a quinone derivative thereof, and/or a polymer of the foregoing catechol material and/or quinone derivative. The antimicrobial layer comprises an antimicrobial cationic polycarbonate covalently linked to the catechol layer.

Abstract: Phosphorus-containing compounds useful for flame retardant epoxy resins are disclosed. The flame retardant epoxy resins may be used to make electrical laminates. This invention is particularly useful in end use applications in which a low bromine or low halogen content is required or desired.

Abstract: The present invention describes the preparation of an aqueous polyurethane dispersion which is cured by radiation, and its use as binder.

Abstract: An antimicrobial silicone rubber comprises a silicone rubber substrate, a catechol layer bound to a surface of the silicone rubber substrate, and an antimicrobial layer disposed on the catechol layer. The catechol layer comprises a catechol material, a quinone derivative thereof, and/or a polymer of the foregoing catechol material and/or quinone derivative. The antimicrobial layer comprises an antimicrobial cationic polycarbonate covalently linked to the catechol layer.

Abstract: The present invention provides curable compositions comprising non-tin metal catalysts that accelerate the condensation curing of moisture-curable silicones/non-silicones. In particular, the present invention provides bismuth(III) sulfonate complexes that are particularly suitable as replacements for organotin in sealant and RTV formulations. In one embodiment, the present invention provides bismuth (III) camphorsulfonate and bismuth(III) methanesulfonate complexes. Further, these bismuth(III) sulfonate complexes are comparable or superior to organotin such as DBTDL, exhibit certain behavior in the presence of components that allow for tuning or adjusting the cure characteristics of the present compositions, and provide good adhesion and storage stability.

Abstract: A silane compound is represented by Formula 1: wherein each R1 is independently a single bond, an ether group, a carbonyl group, a thioether group, a sulfone group, or a substituted or unsubstituted C1 to C20 hydrocarbon group, R2 and R3 are each independently a substituted or unsubstituted C1 to C20 hydrocarbon group, each R4 is independently hydrogen or a C1 to C5 hydrocarbon group, each X is independently halogen, a hydroxyl group, or C1 to C20 alkoxy, each Y is independently a single bond, an amide group, a thioester group, a hydroxyethylene group, a carbonyl group, an aromatic group or an ester group, a and b are each independently an integer from 1 to 3, a+b is 4, m is an integer from 0 to 5, n is an integer from 5 to 50, and p and q are each independently an integer from 0 to 4.

Abstract: Provided is a method for improving thermal stability of polypropylene carbonate and, more particularly, a method of end capping a molecular chain of polypropylene carbonate using a urethane group by adding isocyanates or diisocyanates to a polypropylene carbonate resin, which may optionally be a mixture containing tertiary polyol, so as to delay thermal degradation of the polypropylene carbonate at a high temperature, thereby securing desired thermal stability. Especially, the method capable of being easily applied to reactive extrusion after preparing the polypropylene carbonate has been proposed, thus simplifying production processes and ensuring economical advantages. Moreover, the above method does not deteriorate transparency and specific smoke density characteristics at combustion, which are advantages of the polypropylene carbonate.

Abstract: A flame retardant thermoplastic resin composition includes: (A) about 60% by weight (wt %) to about 90 wt % of a polycarbonate resin including a first polycarbonate having a weight average molecular weight from about 30,000 g/mol to about 50,000 g/mol and a second polycarbonate having a weight average molecular weight from about 5,000 g/mol to about 20,000 g/mol; (B) about 10 wt % to about 40 wt % of an aromatic vinyl resin having a fogging index (FI) of about 0.8 or less as calculated by Equation 1 defined in the specification; (C) about 1 part by weight to about 20 parts by weight of an impact modifier based on about 100 parts by weight of (A)+(B); and (D) about 5 parts by weight to about 30 parts by weight of a flame retardant based on about 100 parts by weight of (A)+(B.

Abstract: Biocompatible methods of functionalising inert surfaces for use in biological applications are described. The methods employ the use of synthetic constructs of the generic structure F-S-L (where F is a functional moiety, S is a spacer selected to provide a construct that is dispersible in water, and L is a diacyl- or dialkyl-glycerophospholipid). An object of the invention is to localise or immobilise functional moieties to the inert surface of a substrate wherein the surface is comprised of glass, silver, polyamide, polycarbonate, polypropylene, polyethersulfone, polytetrafluoroethylene or polyvinylidene fluoride, and the substrate is comprised of a fibre, membrane, microsphere or nanosphere.

Abstract: The present invention pertains to copolymers having one or more polyisobutylene segments and one or more biodegradable polymer segments, to methods of making such copolymers, to medical articles that contain such copolymers, and to methods of making such medical articles. According to certain aspects of the invention, copolymers are provided, which comprise a plurality of polyisobutylene segments and a plurality of biodegradable polymer segments. According to certain aspects of the invention, copolymers are provided, which comprise urethane linkages, urea linkages, amide linkages, ester linkages, anhydride linkages, carbonate linkages, linkages commonly described as “click” chemistry linkages, and combinations of two or more types of such linkages.

Abstract: Disclosed are a polysiloxane-modified polyhydroxy polyurethane resin characterized by being derived from a reaction between a 5-membered cyclic carbonate polysiloxane compound represented by the below-described formula (1) and an amine compound, and its production process; and a resin composition, thermal recording medium, imitation leather, thermoplastic polyolefin resin skin material, weather strip material, and weather strip, all of which make use of the resin.

Abstract: A resin composition having excellent light diffusion property and hue and a molded article thereof. The light-diffusing resin composition comprises 100 parts by weight of a resin component containing a polycarbonate (component A) and a polycarbonate-polydiorganosiloxane copolymer (component B) and 0.05 to 10.0 parts by weight of a light diffusing agent (component C), wherein the component B is a polycarbonate-polydiorganosiloxane copolymer in which polydiorganosiloxane domains having an average size of 0.5 to 40 nm are existent in a polycarbonate matrix.

Abstract: This is to provide a process for preparing a polycarbonate diol diacrylate from a polycarbonate diol and a vinyl acrylate compound without using a protonic acid or a metal component. This is a process for preparing a polycarbonate diol diacrylate which comprises reacting a polycarbonate diol represented by the formula (I) and a vinyl acrylate compound represented by the formula (II) in the presence of a hydrolase, and a polycarbonate diol diacrylate represented by the formula (III) having a terminal acrylated ratio of 97% or more.

Abstract: Methods of making a biodegradable polymeric stent made from poly(L-lactide) and a low concentration of L-lactide monomer is disclosed. The concentration of L-lactide is adjusted to provide a degradation behavior that is suitable for different treatment applications including coronary, peripheral, and nasal. Methods include making a poly(L-lactide) material for a stent with uniformly distributed L-lactide monomer through control of polymerization conditions during PLLA synthesis, control of post-processing conditions, or both.

Abstract: The invention at hand concerns hydrophobic polymer surfaces, in particular superhydrophobic polymer surfaces, comprising at least one homo- or copolymer, which comprises at least one side chain with at least one fluoro-substituted aryl group. Furthermore, the invention at hand concerns a method for the production of polymer surfaces of this type, their use and polymers of the general formula I: wherein n is an integer between 10 and 4,500, preferably between 20 and 2,200 and particularly preferably between 100 and 670.

Abstract: The invention relates to coextrusion binders including renewable and/or biodegradable polymers having good adhesion properties: at least one renewable and/or biodegradable polymer (A) grafted with a functional monomer including at least one reactive function, the grafting ratio being <1% in weight of the grafted polymer (A); at least one non-grafted renewable and/or biodegradable polymer (B) identical to (A) or compatible with (A) optionally a softener (C); and optionally a starch-based material (D). The invention also relates to multilayered structures including the binder of the present invention, in which the layers are preferably made of renewable and/or biodegradable compounds. The multilayered structures are advantageously useful in the field of food packaging.

Abstract: The invention relates to silicone resins comprising metallosiloxane which contains for example Si—O-Aluminium bonds. It also relates to their use in thermoplastics, thermosettings organic polymers or any blends of the laters or rubbers or thermoplastic/rubbers blends compositions to reduce the flammability or to enhance scratch and/or abrasion resistance of the organic polymer compositions. It further relates to coatings containing such silicone resins for scratch and/or abrasion resistance enhancement or flame retardant properties.

Abstract: The invention provides methods for stably binding and immobilizing deoxyribonucleic acid onto objects and substrates. The method includes exposing the deoxyribonucleic acid to alkaline conditions, and contacting the deoxyribonucleic acid to the object or substrate. The alkaline conditions are produced by mixing the deoxyribonucleic acid with an alkaline solution having a pH of about 9.0 or higher, and contacting the deoxyribonucleic acid to the substrate. The immobilized DNA can be used as a taggant and can be used in combination with other detectable taggants, such as optical reporters. Methods for authentication of a DNA marked object are also provided.

Abstract: Phosphorus-containing compounds useful for flame retardant epoxy resins are disclosed. The flame retardant epoxy resins may be used to make electrical laminates. This invention is particularly useful in end use applications in which a low bromine or low halogen content is required or desired.

Abstract: A synthetic bead for use in mineral separation is described. The synthetic bead has a surface made of a synthetic material such as polymer and the synthetic material is functionalized with molecules having a functional group for attracting mineral particles to the surface in a separation process. The synthetic beads can be placed in flotation cell containing a mixture of water, valuable material and unwanted material or in a pipeline where the mixture is transported from one location to another. The enriched synthetic beads carrying the mineral particles are separated from the unwanted materials in the mixture. The mineral particles are then released from the synthetic beads by means of low pH treatment, ultrasonic agitation, thermal or electromagnetic treatment.

Abstract: Disclosed are water-soluble nanoparticles. The water-soluble nanoparticles are each surrounded by a multifunctional group ligand including an adhesive region, a cross linking region, and a reactive region. In the water-soluble nanoparticles, the cross-linking region of the multifunctional group ligand is cross-linked with another cross-linking region of a neighboring multifunctional group ligand.

Abstract: Described as one aspect of the invention are polymer blends comprising at least one polyester wherein the polymer blend comprises: (A) a polyester composition comprising (I) at least one polyester (Polymer A) which comprises: (a) a dicarboxylic acid component comprising: (i) 70 to 100 mole % of terephthalic acid residues; (ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having up to 20 carbon atoms; and (iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues having up to 16 carbon atoms; and (b) a glycol component comprising: (i) about 10 to about 90 mole % of ethylene glycol residues; and (ii) about 90 to about 10 mole % of cyclohexanedimethanol residues; (II) residues of at least one titanium compound; and (III) at least one chelating phosphorus species, reaction products thereof, or mixtures thereof, represented by the structure: wherein: n=an integer from 1 to 4; R can be hydrogen or C1-C22-alkyl; and R1 and R2 each can be hydrogen, C1-C22-alkyl, hydroxyl, or aryl; wh

Abstract: A composition comprises a first polycarbonate having a limited oxygen index of greater than 26% measured according to ISO 4589 on a 4 mm thick plaque, wherein an article molded from the first polycarbonate has a smoke density after 4 minutes (DS-4) of greater than 600 determined according to ISO 5659-2 on a 3 mm thick plaque at 50 kW/m2; and a second polymer different from the first polycarbonate, the second polymer comprising a poly(carbonate-siloxane) copolymer, a polydialkylsiloxane, or a combination comprising at least one of the foregoing; wherein an article molded from the second polymer has a smoke density after 4 minutes (DS-4) of greater than 600 determined according to ISO 5659-2 on a 3 mm thick plaque at 50 kW/m2; wherein an article molded from the composition has a smoke density after 4 minutes (DS-4) of smaller than 480 determined according to ISO 5659-2 on a 3 mm thick plaque at 50 kW/m2.

Abstract: A phosphorous copolymer, a method for preparing the same, and a flame retardant thermoplastic resin composition including the same is disclosed. The phosphorous copolymer includes a repeat unit represented by Formula 1: wherein each A is independently a single bond, C1 to C5 alkylene, C1 to C5 alkylidene, C5 to C6 cycloalkylidene, —S—, or —SO2—; R1 and R2 are each independently substituted or unsubstituted C1 to C6 alkyl or substituted or unsubstituted C6 to C20 aryl; R3 and R4 are each independently substituted or unsubstituted C1 to C6 alkyl, substituted or unsubstituted C3 to C6 cycloalkyl, substituted or unsubstituted C6 to C12 aryl, or halogen; a and b are each independently an integer from 0 to 4; and m and n are each independently an integer from 1 to 500.

Abstract: Polyglycerol carboxylic acid esters are made by reaction of a, typically C2 to C30, particularly C6 to C22, carboxylic acid with glycerol carbonate, particularly with base catalyst, and desirably at temperatures from 170° C. to 250° C. Other carbonates e.g. cyclic diol carbonates such as ethylene or propylene carbonates, may be used in combination with the glycerol carbonate to make novel mixed polymeric esters. The molar ratio of carboxylic acid group to glycerol carbonate is typically from 2 to 30, but can be up to 100. The base catalyst is desirably alkali metal hydroxide, carbonate or alkoxide. The reaction is desirably carried out in an inert atmosphere, and reducing agent such as phosphorous acid, hypophosphorous acid or borohydride and/or activated carbon, may be included to improve product color.

Abstract: A prepolymer prepared by condensation reaction between a first compound represented by Formula (1) below: Ar—H??(1), where Ar is composed of a crosslinkable moiety at one end, a moiety selected from the group —O—, —S—, —COO—, —CO—, —COS—, —SO2—, and —NH—, and one or two repeating units selected from the group: where A is carbon or nitrogen, and X is hydrogen or halogen; and a second compound that is an aromatic moiety.

Abstract: The invention relates to a method for producing polyether carbonate polyols, wherein (i) in a first step a polyether carbonate polyol is produced from one or more H-functional starter substances, one or more alkylene oxides, and carbon dioxide in the presence of at least one DMC catalyst, and (ii) in a second step the polyether carbonate polyol is chain-extended with a mixture of at least two different alkylene oxides in the presence of at least one DMC catalyst. The invention further relates to polyether carbonate polyols that contain a terminal mixed block of at least two alkylene oxides and to a method for producing soft polyurethane foams, wherein a polyol component containing a polyether carbonate polyol according to the invention is used.

Abstract: A membrane includes a metal or coordination complex that selectively interacts with one or more materials. The membrane can be used for facilitated transport separation of the materials. The metal complex can include any suitable metal center, but preferably includes a late transition metal. The metal complex can also include any suitable ligand, but preferably includes a triphosphacyclononane. The metal complex can be covalently linked to the membrane.

Abstract: Provided are an organic-inorganic hybrid scaffold with surface-immobilized nano-hydroxyapatite, and a method for the fabrication thereof. The scaffold is fabricated by reacting an acid group present on a surface of nano-hydroxyapatite with a primary amine present on a surface of a polymer support in the presence of EDC (1-ethyl-3-dimethylaminopropyl carbodiimide) to immobilize nano-hydroxyapatite onto the surface of the polymer support. The surface of nano-hydroxyapatite is previously grafted with poly(ethylene glycol methacrylate phosphate) (PolyEGMP) having phosphonic acid functionality or with a polymer having carboxylic acid functionality.

Abstract: A polycarbonate diol comprising repeating units represented by the following formula (A) and a terminal hydroxy group, 60-100 mol % of the repeating units represented by the formula (A) being repeating units represented by the following formula (B) or (C). The amount of the repeating units represented by the formula (B) is 60-100 mol % based on the total amount of the repeating units represented by the formula (A). The polycarbonate diol has a terminal primary OH ratio of 95% or higher. (A) (In the formula, R represents a C2-12 divalent aliphatic or alicyclic hydrocarbon.

Abstract: The invention relates to a biodegradable multi-block copolymer, comprising at least two hydrolysable segments derived from pre-polymers A and B, which segments are linked by a multi-functional chain-extender and are chosen from the pre-polymers A and B, and triblock copolymers ABA and BAB, wherein the multi-block copolymer is amorphous at physiological (body) conditions. The invention further relates to a process for preparing said copolymer and to its use as a medical implant, a coating for a medical device or a drug delivery vehicle.

Abstract: An antimicrobial composition comprises an anionic drug and an amine polymer comprising a first repeat unit of formula (2): wherein a? is an integer equal to 1 or 2, b? is an integer equal to 1 or 2, and each R? is an independent monovalent radical selected from the group consisting of hydrogen, methyl, ethyl, and combinations thereof. G? is a divalent linking group selected from the group consisting of a single bond and groups comprising at least one carbon. X? is a negatively charged counterion. The drug and the amine polymer are bound by noncovalent interactions.

Abstract: The present invention relates to compositions which comprise highly-branched polycarbonates, to the use of these highly-branched polycarbonates in cosmetics and dermatology and to substituted highly-branched polycarbonates.

Abstract: Disclosed are immiscible polymer blends, plastic articles containing the blends, and methods for making the plastic articles. One type of article is plastic lumber, which can be in the form of a railroad tie or a marine piling.

Abstract: Disclosed is an aramid product in which the number of defects present in noncrystalline regions is considerably reduced and a composition for aramid for producing the same. The composition contains aromatic polyamide and a fused aromatic compound, wherein the content of the fused aromatic compound is 0.01 to 10 parts by weight, based on 100 parts by weight of the aromatic polyamide.

Abstract: A nanocomposite comprises: a polymer; and a nanofiller disposed in the polymer, the nanofiller comprising a first nanoparticle bonded to a second nanoparticle. A process of making a nanocomposite comprises: combining a silsesquioxane and a nanoparticle; bonding the nanoparticle to the silsesquioxane to make a nanofiller; and dispersing the nanofiller in a polymer to make the nanocomposite.

Abstract: The invention provides an adhesive sheet which can be stuck to a wafer at low temperatures of 100° C. or below, which is soft to the extent that it can be handled at room temperature, and which can be cut simultaneously with a wafer under usual cutting conditions; a dicing tape integrated type adhesive sheet formed by lamination of the adhesive sheet and a dicing tape; and a method of producing a semiconductor device using them. In order to achieve this object, the invention is characterized by specifying the breaking strength, breaking elongation, and elastic modulus of the adhesive sheet in particular numerical ranges.