219results about How to "Increased release rate" patented technology

The invention relates to a system and method for obtaining a carbon source by utilizing ultrasonic enhanced sludge hydrolysis. The biological sludge in a municipal sewage plant is used as a raw material; the flocculation structure and cell wall of the sludge are firstly damaged by utilizing a waterpower shear force generated by an ultrasonic cavitation effect; the sludge after ultrasonic preprocessing is added to an anaerobic hydrolysis reactor; and under anaerobic conditions, macromolecular solid organic matters are finally converted into volatile fatty acids (VFAs) such as acetic acid, propionic acid, butyric acid and the like through a series of biological hydrolytic action. In the invention, the efficiency and velocity for a sludge to release a carbon source are improved by utilizing the coupling of ultrasonic processing and anaerobic hydrolysis processes, and the N (nitrogen) and P (phosphorus) which are released by hydrolysis are effectively eliminated and recovered by utilizing a crystallization method. The invention can solve the problem of carbon source insufficiency of the existing denitrification and dephosphorization process and realizes the stabilization and resource of the sludge to some extent. Simultaneously, because the hydrolysis velocity of the sludge is enhanced, the hydrolysis time of the sludge is greatly shortened and the investment and operating cost of engineering are lowered.

The invention discloses a cosmetic containing oceanic shellfish active peptide and a preparation method and application thereof. The cosmetic contains 0.1 to 10 percent of oceanic shellfish active peptide, or 0.1 to 10 percent of oceanic shellfish active peptide and 1 to 10 percent of hyaluronic acid, or 0.1 to 10 percent of oceanic shellfish active peptide, 1 to 10 percent of hyaluronic acid and1 to 25 percent of vitamin C (VC), and the balance is cosmetic matrix components. The peptide is formed by boiling, ultrasonic, enzymolysis and ultra-filtration of oceanic shellfish meat; and besidesthe active peptide, the oceanic shellfish meat also contains free amino acid, glycosaminoglycan, polyunsaturated fatty acid, vitamins, trace elements and the like. The problems of application and thelike of the oceanic shellfish active peptide in the cosmetic are solved; and the prepared cream, emulsion, aqueous agent, gel, aerosol or mask has more complete and remarkable skin-care or hair-care effect. After the hyaluronic acid and the VC are added, the effects of preserving moisture, increasing the elasticity and the smoothness of the skin, removing flaws and improving the skin color are remarkably enhanced.

The present invention relates to microcapsule graphene composite material controlled-release pesticide-fertilizer granules, which comprise mother powder, an inorganic nutrient, an organic matter, an anti-hardening agent and a filler, wherein the mother powder comprises a microcapsule graphene composite material and a pesticide active ingredient, the microcapsule graphene composite material is formed by compounding a polymer compound and graphite powder, and the polymer compound is at least one selected from gelatin, gum arabic, starch, chitosan, alginic acid, methyl cellulose, a carboxymethyl cellulose salt, poly lactic acid, polyamide and polyvinyl alcohol. The preparation method comprises: completely mixing pesticide and graphite powder, crushing, placing the obtained mixture and a polymer compound into a ball mill to grind, carrying out agglomeration, precipitation or polymerization to obtain a mixture of the microcapsule graphene composite material and the pesticide, drying to obtain mother powder, carrying out granulation on the mother powder, an inorganic nutrient, an organic matter and a filler, and spraying an anti-hardening agent on the particles so as to obtain the finished product. According to the present invention, the release is stable, and the problems of fertilizer applying and plant diseases and insect pests of the whole season can be solved with the applying of the granules one time.

The invention discloses a preparation method of a controlled release antibacterial film. The method includes the following steps of: (1) dissolving zein and a hydrophobic antibacterial agent into an alcoholic solution; (2) preparing a sodium caseinate aqueous solution; (3) adding the sodium caseinate aqueous solution into the solution obtained in step (1) under stirring; (4) subjecting the solution obtained in step (3) to rotary evaporation and centrifugation, then freeze drying the supernatant, thus obtaining nanoparticle powder; (5) dissolving a film-forming matrix in water, adding the nanoparticle powder and lysozyme to form a mixed solution; and (6) adding glycerin, and conducting film pouring, thus obtaining the film product. The method provided in the invention can simultaneously reduce initial microbial activity and inhibit microbial growth for a long term, and has the advantages of low instrument requirement, and controllable bacterium inhibiting intensity, thus having broad application prospects in food and medical products.

The invention relates to a method and device for restoring polluted soil and treating solid wastes. A cathode reaction tank and an anode reaction tank are respectively arranged at the two ends of soil / solid wastes, a water supply layer is arranged at the bottom of the soil / solid wastes and contains a chemical agent which can improve the solubility of organic pollutants and heavy metals in water, and a replaceable pollutant collecting layer covers the top of the soil / solid wastes which are internally provided with a replaceable artificial focal zone. The temperature value of the soil / solid wastes is increased to dozens of degrees even hundreds of degrees by applying a high voltage and large current; volatile organic pollutants volatile from the soil / solid wastes due to a high temperature, and nonvolatile organic pollutants and the heavy metals rise to the collecting layer along with water and are left in the collecting layer after the water is evaporated; and partial heavy metal ions are transferred to the electrode tank and the artificial focal zone along the electric field direction. Hydrogen and oxygen generated at a cathode and an anode are respectively collected for burning the volatile pollutants in the collecting layer and the focal zone; and the oxygen also can be made into ozone for oxygenizing pollutants in the soil / solid wastes or be cleared out.

The invention relates to a dual sensitive amphiphilic triblock copolymer containing disulfide bond and acylhydrazone bond and a preparation method and an application of the dual sensitive amphiphilic triblock copolymer. A BAB type amphiphilic triblock copolymer consists of a hydrophobic polyester block A and a hydrophilia polyethylene glycol block B, wherein the block A is polyether containing active terminal amino group and disulfide bond; the block B is benzaldehyde ester of an ethylene glycol monomethyl ether or single terminated polyoxyethylene polypropylene oxide copolymer; the block A and the block B are connected through acid sensitive acylhydrazone bond generated from reaction of active terminal amino group and aldehyde group. The dual sensitive amphiphilic triblock copolymer is good in biocompatibility and biodegradability, can be formed into nanoparticles with oxidation reduction sensitivity and acid sensitivity in a water medium in a self-assembling manner, can wrap hydrophobic medicines to form nano medicine preparations, and can promote rapid release of medicines in tumor cells due to fracture of disulfide bond and acylhydrazone bond which are sensitive to oxidation reduction in a high concentration glutathione and acid micro environment in the tumor cells.

The invention discloses pH-responsive comb-like copolymer and preparation and application thereof. The preparation includes obtaining pH-responsive group by ARGETATRP (activator regeneration by electron transfer and atomic transfer radical polymerization), obtaining hydrophobic group by ROP (ring opening polymerization), using the pH-responsive group and the hydrophobic group to form block copolymer, using the block copolymer as macroinitiator to initiate ARGETATRP of hydrophobic macromers, and obtaining the pH-responsive amphipathic comb-like copolymer by selective hydrolysis reaction. The proportion of functional groups in the polymer molecule is easy to regulate. The synthetic process is simple, and yield is high. The hydrophobic group and the pH-responsive group obtained by dialysis form polymeric micelles of a shell, drug slightly soluble in water can be entrapped in a core of the polymeric micelles, the drug is kept to release slowly in the presence of gastric juice, and the drug is quickly and controllably released in intestines.

The invention discloses compound biochar-based slow-release fertilizer and an application method thereof and mainly relates to the field of biochar-based fertilizer. A preparation method of the compound bio-carbon-based slow-release fertilizer comprises mixing agricultural rice straws and wood shavings, preparing char, adding sodium selenite into the char to obtain biochar, mixing pig manure and chicken manure, carrying out fermentation on the pig manure and chicken manure, carrying out metal passivation treatment to obtain manure-based fertilizer, further fermenting the biochar and the manure-based fertilizer, and adding diatomite into the fermentation product for modification to obtain slow release fertilizer granules. In use, preferably, the slow-release fertilizer granules are applied to the field according to a ratio of 256 kg per mu, and a field moisture capacity measured value is kept in a range of 70% to 80% in the whole growth period. The compound biochar-based slow-release fertilizer can meet the demand of nitrogen and phosphorus in the early stage and the whole period of rice seedling, has sufficient and lasting fertilizer effects, prevents the effects of heavy metals, improves the soil environment, inhibits methylmercury, and can produce high-yield good-quality selenium-rich rice.

The invention relates to a micron / nano aluminum powder composite particle coated with a fluorine-containing polymer and a preparation method thereof. According to the preparation method, firstly, a free radical emulsion polymerization method is adopted to polymerize a layer of the fluorine-containing polymer on the surface of micron / nano aluminum powder in an in-situ mode, so that the fluorine-containing polymer effectively coats the surface of the micron / nano aluminum powder; the activity of the micron aluminum powder or the nano aluminum powder can be effectively protected, the micron aluminum powder or the nano aluminum powder can be prevented from being violently oxidized in the using process, and the high-temperature oxidation rate and the heat release rate of the micron aluminum powder or the nano aluminum powder can be obviously improved; and meanwhile, the dispersity of the micron aluminum powder or the nano aluminum powder can be improved, the problem that the micron / nano aluminum powder is prone to agglomerate and difficult to disperse in the using process is solved, coating is uniform, the density is good, and the coating layer is not prone to falling off.

A semi-floating gate device and a formation method therefor are disclosed. The formation method comprises the steps of providing a substrate, wherein the substrate is provided with a first well region; forming a groove in the substrate, wherein the bottom of the groove is lower than that of the first well region; forming a first dielectric layer on the surfaces of the side wall and the bottom of the groove; forming a floating gate layer on the surface of the first dielectric layer in the groove and the surface of the substrate, wherein the surface of the floating gate layer is higher than that of the substrate; the doping types in the floating gate layer and the first well region are opposite; etching a part of the floating gate layer to form a floating gate, wherein the floating gate comprises a first structure positioned in the groove, and a second structure positioned on the partial surface of the first structure; the second structure is in contact with a partial first well region on one side of the groove; the second structure exposes the top of the first dielectric layer that is positioned on the surface, on the other side of the groove, of the side wall; forming a second dielectric layer on the surface of the floating gate, wherein the second dielectric layer is connected with the first dielectric layer exposed by the floating gate; and forming a control gate on the surface of the second dielectric layer. The performance of the formed semi-floating gate device is improved.

The invention relates to a liquid hydrogen storage material and a preparation method thereof. The liquid hydrogen storage material comprises a carbazole type hydrogen storage component and an additivewith a low melting point and a high heat transfer coefficient; the carbazole type hydrogen storage component is at least one of carbazole, N-methyl carbazole, N-ethyl carbazole, N-n-propyl carbazole,N-isopropyl carbazole or N-n-butyl carbazole; the heat conduction additive component with a low melting point is at least one of benzyltoluene or hydrogenated terphenyl. The liquid hydrogen storage material is a mixture formed by mixing the carbazole type hydrogen storage material with a high melting point with the heat conduction additive with a low melting point and has an eutectic point whichis at least lower than the melting point of one component, and the melting point of the entire hydrogen storage material can drop to 0 DEG C or below. At the same time, the heat conduction additive with a low melting point has a high heat transfer coefficient, and the heat conductivity coefficient of the mixture formed after the additive is mixed with the carbazole type hydrogen storage material can be higher than that of the carbazole type hydrogen storage material; the whole hydrogen storage material can quickly reach the dehydrogenation temperature during dehydrogenation, so that the release rate of hydrogen is increased.

On one hand, the invention provides a composition of a covalent conjugate of an eflornithine analogue and an anti-inflammatory. On the other hand, the invention provides an eflornithine prodrug composition. In addition, the invention provides a method for treating or preventing cancer by using the conjugate of the eflornithine analogue or the eflornithine prodrug.

The invention discloses a fragrant immobilized granular activation-free chlorine dioxide air purifying agent and belongs to the field of environmental purification. The air purifying agent includes following components: a solidifying agent, a chlorine dioxide generating substance, spices, a coloring agent, a slow-releasing agent, a filling agent and the like. A preparation method includes the steps of material preparation, grinding, drying, sieving, mixing and moulding. The air purifying agent can effectively kill bacteria, virus, chemical toxins and residual pesticides and the like harmful substances. The air purifying agent is convenient to use, is simple in operation, is significant in effects, is long-acting, safe and long-shelf-life, and has wide application prospect in the fields of household environments, medical care and health care, hygiene and epidemic prevention and the like.

The invention provides a preparation method of an atorvastatin calcium capsule preparation, and the method comprises the following steps: uniformly mixing amorphous atorvastatin calcium with a water-soluble solid dispersion carrier; heating to melt the solid dispersion carrier, and cooling and curing after the amorphous atorvastatin calcium is uniformly dispersed in the molten dispersion carrier; drying the obtained mixture at a low temperature to obtain mixture particles; and then mixing the obtained particles with other medicinal auxiliary materials, and filling into capsules. By utilizing the preparation method provided by the invention, the dispersion degree of the atorvastatin calcium raw material is improved, the granularity of the medicament is reduced, and the specific surface area is increased, so that the dissolution rate is improved.

The invention provides a haematococcus pluvialis solid dispersion, and a preparation method and applications thereof. The provided haematococcus pluvialis solid dispersion is composed of three phases namely dry algae residues prepared by subjecting haematococcus pluvialis to CO2 supercritical extraction, microencapsulated powder prepared by subjecting the haematococcus pluvialis extract obtained by CO2 supercritical extraction to microencapsulation, and a solid dispersion carrier. The invention also provides a preparation method and applications of the haematococcus pluvialis solid dispersion. The experiment results show that the astaxanthin stability, bioavailability, and anti-oxidation activity of the haematococcus pluvialis solid dispersion are obviously better than those of the cell-wall-broken haematococcus pluvialis, CO2 supercritical extract, and microencapsulated powder prepared by subjecting the CO2 supercritical extraction extract to microencapsulation.

The invention relates to an infrared detector with a multilayer structure based on a CMOS (complementary metal oxide semiconductor) process, a CMOS measuring circuit system and a CMOS infrared sensing structure in the infrared detector are both prepared by using the CMOS process, and the CMOS manufacturing process comprises a metal interconnection process, a through hole process, an IMD (in-mold decoration) process and an RDL (redistribution layer) process; in the infrared detector with the multi-layer structure, a first columnar structure comprises at least one layer of solid columnar structure and / or at least one layer of hollow columnar structure, a second columnar structure comprises at least one layer of solid columnar structure and / or at least one layer of hollow columnar structure, at least one hole-shaped structure is formed in an absorption plate, and the hole-shaped structure at least penetrates through a dielectric layer in the absorption plate; and / or at least one hole-shaped structure is formed on a beam structure. The infrared detector is advantaged in that problems of low performance, low pixel scale, low yield and poor consistency of a traditional MEMS process infrared detector are solved, the planarization degree of the absorption plate is optimized, thermal conductivity of the beam structure is reduced, and the performance of the infrared detector is optimized.

The present invention relates to a novel controlled release carrier system for pH or salt triggered release and targeted delivery of fragrances and other active ingredients onto fabric, hair, skin, and other biological surfaces and which provides prolonged release of fragrances and other active ingredients over an extended period of time, or yields a high impact fragrance "burst" upon treating the target surface with heat (blow drying the hair, ironing the fabric). The controlled delivery system of the present invention is substantially a free-flowing powder formed of solid hydrophobic nano-spheres comprising the fragrance and other active ingredients that are encapsulated in a pH or salt sensitive micro-spheres. Also described are processes for preparing such compositions and processes for using same. Furthermore, certain components of the aforementioned compositions in combination with one another are novel, and other components have novel uses in increasing fragrance substantivity, particularly in fabric, hair, and skin care preparations. The invention further pertains to consumer and diversified products comprising the controlled release system of the present invention.

The invention provides an acid-sensitive amphipathic stearic acid amidated glucan polymer nano-micelle and a preparation method thereof and relates to a drug-loading micelle and a preparation method thereof. According to the acid-sensitive amphipathic stearic acid amidated glucan polymer nano-micelle and the preparation method, the problem that stearic acid glucan micelles in the prior art have no pH response property. According to the preparation method, a stearic acid amidated glucan polymer is prepared from glucan as a raw material by virtue of oxidization, hexamethylendiamine reduction reaction and stearic acid amidation and is self-assembled in water by virtue of amphipathicity so as to form the nano-micelle. The preparation method comprises the following steps: (1) preparing polyaldehyde glucan; (2) preparing hexamethylendiamine-polyaldehyde glucan; (3) preparing stearic acid amidated glucan; and (4) carrying out self-assembling to form the nano-micelle, so as to obtain the acid-sensitive amphipathic stearic acid amidated glucan polymer nano-micelle. The acid-sensitive amphipathic stearic acid amidated glucan polymer nano-micelle prepared by virtue of the preparation method is used as a carrier of hydrophobic antitumor drugs.

The invention discloses a preparation method of a wear-resisting ceramic tile capable of releasing a negative ion. A finished product of the ceramic tile is obtained by ball-milling a powder material,pulping, spraying a powder, forming, biscuiting, glazing, glaze-firing and edging; a used glaze comprises a negative ion powder; the powder material comprises potassium feldspar, albite, nepheline, kaolin, washing mud, barium carbonate, calcined talcum, nano-zinc oxide, methylcellulose, sodium tripolyphosphate, a preservative. The preparation method adopts the low-temperature biscuiting and high-temperature glaze-firing process; the ceramic tile produces a large quantity of negative ions, the glaze is flat and smooth, the resistance to thermal shock and the stain resistance are good, and thepreparation method has excellent performances of wear resistance and acid corrosion resistance, and has excellent economic and social benefits.

The invention relates to a slow release type chlorine dioxide solid disinfectant and a preparation method thereof. The slow release type chlorine dioxide solid disinfectant is composed of a component A, a component B and a double-layer slow release device. The component A comprises chlorine dioxide parent, a reducing agent, a filling agent, a stabilizer and a slow release carrier. The component B comprises acid solution. The component A is placed in the double-layer slow release device, and the component B is independently packaged. The preparation method is simple, and the slow release type chlorine dioxide solid disinfectant is suitable for industrial large-scale production, convenient to use, easy to store and long in guarantee period and has good application prospects in the fields such as home furnishing, environmental protection and health defence. The slow release type chlorine dioxide solid disinfectant can be used for deodorization and disinfection of a refrigerator, a toilet, a shoe cabinet, a storage room and the inside of a vehicle and the like.

The invention discloses a vector tile real-time slicing and updating method based on multi-layer cache, which comprises the following steps of: retrieving in a spatial database according to an input map range, judging whether data updating is involved or not, and returning a complete geometrical shape of updated data to a minimum bounding rectangle to generate a corresponding vector tile; establishing a retrieval identifier according to the request range for generating the vector tiles, retrieving the memory database through the retrieval identifier, returning a retrieval result if the retrieval identifier exists, and retrieving the non-relational database if the retrieval identifier does not exist; if the search result exists in the non-relational database, loading the search result intoa cache and returning the search result; and if not, calling a vector tile slicing tool to generate vector tiles in real time, storing the generated vector tiles into a memory database or a non-relational database, establishing a file index, and returning the vector tiles. The publishing efficiency of the vector tile data is effectively improved, and the requirements of a user for instant generation and updating of mass data are met.

The invention discloses nano-drug carrier particles capable of controlling drug release. The particles have a core-shell structure, wherein a gold nano-cage (1) which is provided with a mesoporous surface and has a hollow structure is arranged in the innermost layer; a polymer PAH layer (2) carrying positive electricity is used for modifying the surface of the gold nano-cage (1); a pH sensitive lipid layer (3) is arranged on the outer surface coating layer of the polymer PAH layer (2). Under pH and light external excitation trigger, gating is switched from a 'closed' state to an 'open' state, and drug molecules are released. The carrier particles can be used for effectively improving the efficiency of cancer chemotherapy.

The invention discloses a lansoprazole enteric-coated tablet and a preparation method thereof. The preparation method comprises the following steps: preparing lansoprazole and pharmaceutic adjuvants comprising starch, lactose, microcrystalline cellulose, hydroxypropyl cellulose, sodium carboxymethyl starch, calcium hydrogen phosphate, povidone K30, sodium hydroxide, magnesium stearate and the like into a tablet core; coating the tablet core with an isolated layer, and finally coating the tablet core with an enteric-coated layer so as to obtain the lansoprazole enteric-coated tablet. According to the method, the solubility and releasing rate of the lansoprazole are effectively improved, so that the oral bioavailability of the lansoprazole is improved. The formula process for preparing the lansoprazole enteric-coated tablet is simple, convenient and stable, and is suitable for mass industrial production.

The invention discloses a production technology of an amoxicillin capsule. The production technology comprises the steps of carrying out a soft material preparation procedure, namely firstly weighing1,000 parts of amoxicillin raw material powder and 8-12 parts of pregelatinized starch, adding the raw materials to an ultrafine grinder for grinding and mixing evenly to prepare a fine powder mixture of which the particle sizes are 900 meshes; adding 20-28 parts of purified water to the fine powder mixture, stirring and mixing evenly, then preparing amoxicillin particles in a wet granulator and drying by using a boiling dryer to obtain dried amoxicillin particles; carrying out a granulation procedure, namely crushing the dried amoxicillin particles, granulating through a 50mesh sieve and adding 18-23 parts of carboxymethyl starch sodium and 3-5 parts of magnesium stearate for mixing evenly; and finally carrying out a filling and polishing procedure and a packaging procedure to obtain a finished product amoxicillin capsule. The prescription and the technological process of the amoxicillin capsule are improved, the dissolution rate of the capsule is improved, oral absorption is complete, the curative effect is improved and the toxic and side effects are reduced.

The invention discloses a medicine preparation of trypsin enteric coated pellets. The preparation consists of active trypsin powder, a polyol medical excipient, a disintegrant and an enteric coating material containing an anti-adhesion agent. The pellet medicine preparation of the invention is prepared by an extruding-rolling technique. The preparation is used for treating dyspepsia, gastricism caused by pancreatic diseases and dyspepsia of diabetic patients, etc.

The invention discloses a method for improving high-temperature thermal reaction properties of aluminum powder through surface modification. According to the method, a modifying agent is added to an aluminum powder aqueous phase suspension solution; the modifying agent belongs to an acid solution or fluoride; an inertia oxidation layer on the surface of aluminum powder is subjected to microcorrosion through the modifying agent, and the modified aluminum powder with the porous rough surface is formed. The high-temperature oxidation rate and heat release rate of the aluminum powder are increasedthrough the modified aluminum powder, and then the high-temperature oxidation combustion performance of the aluminum powder is improved.

The invention discloses a direct field-returning and decomposition promoting method for rice stubble and wheat straw in an area along Huaihe river, which comprises the following operating steps: (1) straw smashing and direct returning to a field; (2) application of a base fertilizer and C / N ratio regulation; (3) application of a straw decomposition agent and field-planting promoting with degradingbacteria; (4) soil rotary tillage and irrigation; and (5) transplanting of seedlings, topdressing and activation of degrading bacterium activity. The invention provides the direct field-returning anddecomposition promoting method for the rice stubble and wheat straw in the area along Huaihe river, the method has good effects of returning the straw to the field and promoting decomposition and isbeneficial to the accumulation of soil nitrogen and the increase of the crop yield.

The invention discloses polymeric micelle having hydrophilic and hydrophobic terminals and having pH response, which comprises a structure shown as a formula (1). The invention also discloses a preparation method of the polymeric micelle and an application of the polymeric micelle as a water-insoluble medicine system. The polymeric micelle has good biocompatibility, and comprises pH-responded polyacrylic acid as a a hydrophilic terminal, and takes hydrophobic group and a pH-responded group random copolymer as a hydrophobic terminal, a core and a shell layer of the micelle have pH response groups, so that the micelle can rapidly and thoroughly respond the pH change of response environment, and phenomenon of burst release of the medicine in stomach and incomplete release of the medicine in small intestine can be effectively eliminated.

The invention belongs to the crossing field of porous organic polymer materials and catalytic chemistry, and discloses a novel carbon dioxide reduction photocatalyst and a preparation method thereof. A series of porous organic polymers NiPc-MPOP which simultaneously contain M-N4 and M-N2O2 monatomic sites are designed and prepared. The polymer not only can synergistically improve the catalytic efficiency, but also provides a more direct opportunity to recognize the activity of a metal center. The photo-reduction result of CO2 shows that excellent CO generation capability (7.77 mmol g <-1 >) can be realized by introducing a catalytic center with Ni-N2O2 into an original phthalocyanine-based Ni-N4 framework, and the selectivity of H2 is as high as 96%. In combination with control experiments and theoretical researches, compared with the traditional Ni-N4 part, the Ni-N2O2 part is proved to be a part with higher CO2RR activity. By changing the coordination environment, the more effective monatomic catalyst is designed, and a new thought and theoretical basis are provided for design and synthesis of the efficient monatomic catalyst.