395 results about "Succinimide" patented technology

The invention relates to an antibody endocytosis efficiency detection method based on fluorescence resonance energy transfer, and belongs to the technical field of antibody endocytosis detection. The method comprises the following steps: coupling succinimide ester with an amino-containing compound to obtain a quenching agent, incubating an antibody to be detected and a target cell together, adding a fluorescence-labeled secondary antibody to carry out endocytosis reaction, removing an extracellular fluorescence signal by using the quenching agent after the reaction is finished, and detecting an intracellular fluorescence signal to obtain the endocytosis percentage of the antibody to be detected. The detection method provided by the invention is based on a fluorescence resonance energy transfer principle, an intracellular signal direct detection method in the prior art is optimized, and an extracellular fluorescence signal is removed, so that a detection system has higher sensitivity. The quenching agent provided by the invention can also be combined with an acid eluent in the prior art to further reduce an extracellular signal background value and improve the sensitivity of a detection system, can be applied to high-throughput detection of a to-be-detected antibody, is high in sensitivity and low in detection cost, and has a good application prospect.

The invention belongs to the technical field of biological materials and ultrasonic printing, and particularly discloses a biological adhesive for ultrasonic printing and preparation and application thereof. The biological adhesive comprises a heat-sensitive main body material and a chemical adhesion component, the heat-sensitive main body material comprises hydroxybutyl chitosan, and the chemical adhesion component comprises polyacrylic acid-N-hydroxysuccinimide ester. The bioadhesive has excellent ultrasonic responsiveness, formability and bioadhesion performance, directional deposition, in-situ solidification and tissue surface adhesion can be achieved in a non-contact and accurately-controlled ultrasonic printing system, and the bioadhesive is suitable for various biomedical scenes such as tissue repair, minimally invasive medicine, biological device construction and drug delivery interface printing.

The invention relates to the technical field of new material application, and discloses a magnetic bead material for enriching a sulfydryl peptide fragment and a preparation method thereof.The magnetic bead material prepared from micron carboxyl magnetic beads, dodecane dicarboxylic acid dihydrazide and SPSP has a long chemical reaction connecting arm, so that a reaction group has the better freedom degree, the reaction with sulfydryl is better facilitated, and the magnetic bead material can be used for enriching the sulfydryl peptide fragment. The enrichment efficiency is relatively high. When the magnetic bead material is prepared, micron carboxyl magnetic beads and dodecane dicarboxylic acid dihydrazide are based on hydrazine group and carboxyl condensation, the condensation reaction is more selective and more stable, the reaction is carried out under a milder condition, the reaction product is stable, and the reaction efficiency is higher at a lower reaction temperature. Dodecane dicarboxylic acid dihydrazide and SPSP are based on a reaction of N-succinimide and hydrazine, N-succinimide has high specificity to amino-containing molecules, side reactions are reduced, the reaction is generally carried out at room temperature, strong acid and alkali conditions are not needed, and protection of other sensitive groups is facilitated.

The invention discloses a hydrogel for gastric perforation repair, which belongs to the field of bioadhesives. The technical scheme is as follows: a hydrogel for gastric perforation repair is generated by chemical reaction of compound A and compound B; compound A is a polyethylene glycol derivative A with a terminal active group α; the terminal active group α is succinimidyl succinate; compound B is a polyethylene glycol derivative B with a terminal active group β; the terminal active group β is an amino group; when compound A reacts with compound B, the terminal active group α and the terminal active group β chemically react to form an amide bond. The beneficial effects of the invention are as follows: the hydrogel for gastric perforation repair provided by the invention has a fast gelation speed, can be gelled in situ, is easy to use, has strong adhesion to gastric tissue, has a low swelling rate in simulated gastric fluid and PBS solution, has a strong ability to resist simulated gastric fluid corrosion, has good compression resistance and anti-peristalsis performance, has good biocompatibility, and can be safely degraded.

The invention discloses a high-performance clean type anti-wear hydraulic oil complexing agent which is prepared from the following substances in parts by mass: 30 to 60 parts of an antioxidant, 20 to 40 parts of an anti-wear agent, 2 to 5 parts of boronized polyisobutylene bis-succinimide, 2 to 7 parts of thiocarbamate, 4 to 10 parts of dodecenylsuccinic acid and 0.2 to 2 parts of graphene nanosheets. The lubricating oil is prepared from the following components in parts by weight: 0.5-1.5 parts of a metal deactivator, 0-2 parts of DISUPER S24 and 30-50 parts of base oil. The preparation method comprises the following steps: S21, heating the base oil, adding the boronized polyisobutylene bis-succinimide and the thiocarbamate, and stirring; s22, sequentially adding an antioxidant, an anti-wear agent, dodecenylsuccinic acid, DISUPER S24 and a metal deactivator into the solution obtained in the step S11, heating to 80 DEG C, and reacting for 2 hours; and S23, adding graphene nanosheets into the solution obtained in the step S22, and carrying out ultrasonic dispersion for 1 hour to obtain the product.

The invention discloses a non-phosphorus reverse osmosis scale inhibitor and a preparation method thereof, and relates to the technical field of industrial water treatment.The non-phosphorus reverse osmosis scale inhibitor is prepared from, by weight, 10 parts of purified humic acid, 40-60 parts of alkalized acrylic acid-succinimide-hydroxypropyl methacrylate copolymer, 4-8 parts of sodium polyepoxysuccinate and 5-20 parts of water. Compared with the prior art, the scale inhibitor is high in environment-friendly compliance, excellent in scale inhibition performance, scientific and efficient in raw material treatment and high in product scale inhibition rate, meets the environment-friendly emission standard, and is suitable for reverse osmosis membrane scale inhibition treatment in the industries of electric power, chemical engineering, seawater desalination and the like.

The invention discloses a bionic self-crimping material and application in the nerve field, and relates to the technical field of nano materials. The preparation method comprises the following steps: firstly, carrying out ultraviolet photopolymerization on acrylic acid and acrylic acid-N-hydroxysuccinimide, adding chitosan and glutaraldehyde to form hydrogel, and introducing epigallocatechin gallate into a chitosan-acrylic acid network. The material is rapidly and autonomously curled into a tube shape after being in contact with wet nerves, glutaraldehyde is directionally and orderly diffused by adopting a three-channel micro-fluidic chip, and the fineness is improved, so that the matching degree of nerve broken ends with different thicknesses is increased; the surface active groups of the material and the natural component chitosan cooperate to realize suture-free fixation; the plant phenol antioxidant removes free radicals at nerve injury parts; the degradation period is synchronous with natural healing of nerves, and secondary operation for taking out is not needed. The electroneurographic signals using the material are transmitted more smoothly, the target muscle atrophy degree is reduced, and the limb movement function is recovered to be close to the normal level.

The invention belongs to the technical field of water treatment, and particularly discloses a green scale inhibitor for barium sulfate and a preparation method thereof, the scale inhibitor is a product generated by esterification reaction of polysuccinimide and hydroxyethyl methylacrylate under alkaline conditions, and a copolymer formed by graft copolymerization of aconitic acid and sodium lignin sulfonate, wherein the mass ratio of polysuccinimide to hydroxyethyl methylacrylate to aconitic acid to sodium lignin sulfonate is 2: 4: (1-6): (1-4). The scale inhibitor is a composite copolymer formed by polymerizing and grafting a product obtained after esterification of polysuccinimide / hydroxyethyl methylacrylate, aconitic acid and sodium lignin sulfonate, has carboxyl, hydroxyl, amino, sulfonic acid and other groups at the same time, and can generate strong interaction with key ions or sites in the BaSO4 crystal growth process, so that the scale inhibitor can be used for inhibiting the growth of BaSO4 crystals. The normal growth and aggregation of BaSO4 crystals are prevented, so that the formation of BaSO4 scales is effectively inhibited.

The invention discloses a preparation method of deuterated methylamine hydrochloride and a solid-phase continuous flow synthesis system, and relates to the technical field of deuterated synthesis. The preparation method comprises the following steps: adding out-of-phase polykadexide into methyl trifluoromethanesulfonate and 1, 2-dichloroethane for heating reaction, then adding methanol for quenching reaction, washing and drying to obtain an out-of-phase polykadexide type methyl reagent; the method comprises the following steps: adding a heterophase polysulfide-type methyl reagent into a mixed solvent of a polar solvent and heavy water, and carrying out alkali treatment to complete deuteration conversion, so as to obtain a heterophase polysulfide-type deuterated methyl reagent; the preparation method comprises the following steps: dissolving o-phenylsuccinimide in acetonitrile, and adding a heterophase polysulfide deuterium methyl reagent and inorganic alkali to react, so as to obtain N-(1, 1, 1-trideuterium methyl) benzo-succinimide; the preparation method comprises the following steps: hydrolyzing N-(1, 1, 1-trideuterium methyl) benzo-succinimide and hydrochloric acid in an aqueous solvent to obtain deuterated methylamine hydrochloride. The preparation method is simple, the deuterium source is cheap, the atom utilization rate is high, the deuteration rate is high, and the production cost is low.

The invention provides an antibody-drug conjugate as well as a preparation method and application thereof. The antibody-drug conjugate comprises an antibody, an effective load with cytotoxicity and a connexon shown in a formula I, and the connexon shown in the formula I is in thioether bond connection with a sulfydryl part reduced by a disulfide chain between antibody chains through a succinimide group; the carbonyl group in the ester group of the linker is connected with the amino group in the effective load. The antibody-drug conjugate can be used for preparing a therapeutic agent for diagnosing, preventing and treating tumor diseases.

The present invention relates to a microneedle-based transdermal delivery patch fabricated from a hydrogel composed of polyvinyl alcohol (PVA), arginine-modified chitosan, and a crosslinker. The arginine-modified chitosan is prepared by reacting a chitosan solution with an arginine solution preactivated with N-hydroxy succinimide and 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide at a specific pH. The hydrogel's formulation further comprises a PVA concentration ranging from 10% to 12% (w / v). arginine-modified chitosan and PVA solution are mixed in a 1:2 ratio by volume and are crosslinked using trimethyl orthoformate (TMOF). The patch is further loaded with curcumin, with a concentration of 120μg per patch, demonstrating a 70% release over 48 hours in a controlled manner. This invention represents the first application of PVA crosslinked arginine-modified chitosan hydrogel loaded with curcumin specifically for animal wound healing, providing enhanced wound healing and antibacterial efficacy.

The invention provides a preparation method of Fmoc-Lys (Ivdde)-OH, which comprises the following steps: reacting dimedone with isovaleric acid under the action of a condensing agent to generate an intermediate compound, then reacting with N-alpha-tert-butoxycarbonyl-L-lysine under the action of organic alkali to obtain an intermediate, then reacting with acid to obtain an intermediate, and finally, separating and purifying the intermediate to obtain the Fmoc-Lys (Ivdde)-OH. Finally, under the action of inorganic alkali, the Fmoc-Lys (Ivdde)-OH reacts with fluorenylmethoxycarbonyl succinimide, and Fmoc-Lys (Ivdde)-OH is obtained. According to the method provided by the invention, the diketone is taken as a starting raw material, Fmoc-Lys (Ivdde)-OH is synthesized through four steps of reaction including two-step condensation reaction, Boc removal reaction and Fmoc feeding reaction, the process is simplified, the operation is simple, the reaction condition is mild, the industrial production difficulty is reduced, expensive raw materials are not involved, the production cost is favorably controlled, and the obtained product is high in purity and high in yield.

The invention discloses a probe Cvs-B-NHS based on a coumarin derivative as well as a preparation method and application of the probe Cvs-B-NHS. According to the fluorescent probe Cvs-B-NHS of the coumarin derivative, a coumarin mother nucleus and succinimide ester are organically combined, the excellent fluorescence characteristic of coumarin is reserved, efficient protein labeling capacity is achieved, high-sensitivity fluorescence signal output and specific labeling of protein are achieved, and the fluorescent probe Cvs-B-NHS has the advantages of being high in sensitivity and high in sensitivity. And the accuracy and reliability of protein detection and imaging are improved. The invention discloses a TDP-43 protein phase separation labeling method based on a Cvs-B-NHS probe, which provides a new means for researching the action mechanism of a TDP-43 (G335D) mutant in neurodegenerative diseases, and is beneficial to promoting the research progress in the field of neurodegenerative diseases. The application of the Cvs-B-NHS probe in evaluating the polarity change of the microenvironment in the protein liquid-liquid phase separation process in the cytoplasm environment caused by mitochondrial signal disturbance provides a powerful tool for the research of the protein phase separation microenvironment.

The invention belongs to the field of polytetrafluoroethylene microporous membranes, and particularly relates to a polytetrafluoroethylene microporous membrane with a high interception rate and a preparation method thereof. The polytetrafluoroethylene microporous membrane is prepared from the following raw materials in parts by weight: 40 to 50 parts of polytetrafluoroethylene resin powder, 1 to 10 parts of paraffin oil, 1 to 5 parts of alkyl acrylate, 1 to 5 parts of ethylene oxide acrylic resin and 5 to 10 parts of polyalkenyl succinimide. Alkyl acrylate and ethylene oxide acrylic resin can improve wear resistance and corrosion resistance; the high temperature resistance, chemical corrosion resistance and low-temperature flexibility can be improved, the size and distribution of pores are controlled by adjusting the stretching ratio, and the interception rate is improved on the premise that permeability is guaranteed.

The invention provides a synthesis method of an OLED polycyclic fused thiophene compound, and relates to the technical field of material synthesis, and the synthesis method comprises the following steps: providing and mixing 2-naphthalene sulfonic acid and dichloromethane, dropwise adding an N-bromosuccinimide solution into the mixture under the protection of inert gas, and reacting to obtain an intermediate A; dissolving the intermediate A, then adding sodium hydroxide, 4-bromophenylboronic acid, water and tetrakis (triphenylphosphine) palladium, and reacting to obtain an intermediate B; dissolving the intermediate B, adding sulfonic acid and phosphorus pentoxide, and reacting to obtain an intermediate C; adding the intermediate C into tetrahydrofuran, dissolving, adding lithium aluminum hydride under inert gas, and reacting to obtain a target compound. According to the method, the chemical reaction efficiency of the intermediate C is high, and the yield and LC purity of a target product are relatively high.

The invention discloses a method for preparing brominated polystyrene, and belongs to the technical field of brominated polystyrene preparation. The method comprises: preparing a main chain bromination inhibitor, preparing a catalyst, and reacting; in the reaction, polystyrene and ethylene dichloride are mixed, stirred at 35-40°C for 30-40min under the protection of nitrogen, then cooled to 0-2°C, the main chain bromination inhibitor and the catalyst are added, stirred for 20-30min, and a dichloroethane solution of N-bromosuccinimide is added dropwise, and after the addition is completed, the mixture is stirred at room temperature for 1.5h, the reaction is terminated, and the mixture is washed with a sodium hydroxide aqueous solution, washed with water, and then filtered, and the filtrate is evaporated and crystallized, filtered, and vacuum dried to obtain brominated polystyrene; the brominated polystyrene prepared by the invention has good color performance and thermal stability, high bromine content, narrow molecular weight distribution, good reaction controllability, and short reaction time.

The invention provides moldable hemostatic putty as well as a preparation method and application thereof. The hemostatic putty comprises hemostatic powder and a solvent, wherein the hemostatic powder comprises gelatin particles and a polysaccharide compound containing an aldehyde group or a succinimide ester group, and the gelatin particles are cross-linked gelatin particles coated with an active substance. The hemostatic putty disclosed by the invention has good flexibility, moldability, adhesion plugging property and degradability, can be kneaded and molded into any shape to be filled at a bleeding part of a bone wound surface, and forms adhesion plugging on the bleeding part, so that a good plugging hemostatic effect is realized. Active substances are wrapped in a network structure of crosslinked gelatin to form a stable core-shell structure, so that the active substances can be prevented from influencing the adhesion plugging property and hemostatic effect of a final product, and the active substances can be slowly released along with degradation of the gelatin, so that generation of new callus is induced or accelerated, and bone healing is accelerated.

The invention provides a thermo-sensitive triblock copolymer with a lateral group containing polyethylene glycol and a preparation method of the thermo-sensitive triblock copolymer, and relates to the field of polymer synthesis. The preparation method comprises the following steps: carrying out a reaction on hydroxyl-terminated polyether PAGE and single carboxyl-terminated polyethylene glycol monomethyl ether (mPEG-COOH) under the action of N-bromosuccinimide to prepare a polymer brush PAGE-g-mPEG; and reacting the polymer brush PAGE-g-mPEG with poly (N-isopropylacrylamide) to generate a thermo-sensitive triblock copolymer of which the side group contains polyethylene glycol. The thermo-sensitive triblock copolymer disclosed by the invention is endowed with good biocompatibility, hydrophilicity and low-temperature performance, has a good thermo-sensitive characteristic, and can be widely applied to the fields of drug-loaded controlled release, sewage treatment and nanoparticles; the invention also provides a preparation method of the thermo-sensitive triblock copolymer, which overcomes the defects of harsh reaction conditions and easy chain extension reaction, and realizes accurate control of the molecular weight of the prepared copolymer.

The invention belongs to the technical field of petrochemical anticorrosion, and provides a multifunctional water-soluble corrosion inhibitor for an oil refining device and a preparation method of the multifunctional water-soluble corrosion inhibitor, and the corrosion inhibitor is a functionalized grafted copolymer obtained by a ring-opening reaction of a succinimide ring on a polysuccinimide intermediate and a plurality of amino-containing compounds; the amino-containing compound at least comprises gemini imidazoline quaternary ammonium salt with a corrosion inhibition function; a polyaspartic acid chain segment precursor with scale inhibition and dispersion functions; the organic amine compound has targeted chelating and pH buffering functions and contains sulfonic acid groups and carboxyl groups; according to the invention, double-anchored gemini imidazoline quaternary ammonium salt is taken as a corrosion inhibition core, and a polysuccinimide ring-opening grafting process is combined, so that chain segments with corrosion inhibition, scale inhibition, targeted buffering and temperature-sensitive self-repairing functions are covalently integrated into a same polymer main chain, and multi-functional efficient protection of a single agent in an oil refining device water phase system is realized.

The invention discloses a graft copolymerization modified high-water-retention formaldehyde-free adhesive as well as a preparation method and application thereof, and belongs to the technical field of adhesive preparation. The adhesive is prepared from the following components: deionized water, vegetable protein meal powder, cationic polyamide polyamine epichlorohydrin resin and an anionic moisturizing factor, wherein the anionic moisturizing factor is prepared from the following components: deionized water, an initiator, acrylamide, itaconic acid, chitosan, hydrochloric acid, N, N '-methylenebisacrylamide, 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxy succinimide. According to the invention, acrylamide, itaconic acid and chitosan are subjected to a graft copolymerization reaction, a moisturizing factor with negative charges is formed in situ in the process, and the moisturizing factor is compounded with polyamide polyamine resin with positive charges for use, so that not only can the water retention capacity of the plant protein adhesive be remarkably improved, but also the mechanical strength characteristic of the plant protein adhesive can be synchronously enhanced.

The invention discloses a method for preparing chiral succinimide through asymmetric hydrogenation of alpha-alkylene succinimide under the catalysis of nickel. The method comprises the following steps: in a solvent, under certain hydrogen pressure and temperature, alpha-alkylene succinimide represented by a general formula (1) is hydrogenated into a chiral succinimide compound represented by a general formula (2) by a nickel chiral catalyst; the structural formulas of the general formulas (1) and (2) are shown in the specification. The method is mild in reaction condition, simple and convenient to operate, capable of achieving good yield and efficiency and wide in application prospect.

A lubricating composition comprises an oil of lubricating viscosity, a phenolic antioxidant, a sulfurized organic compound having an active sulfur content of no more than 8% by weight, and optionally one or more performance additives selected from the group consisting of succinimide dispersants and detergents. Further, a method for improving the oxidative stability of a lubricating oil in an engine comprises supplying to the engine a lubricating composition comprising an oil of lubricating viscosity, a phenolic antioxidant, a sulfurized organic compound having an active sulfur content of not more than 8% by weight, and optionally one or more performance additives selected from the group consisting of succinimide dispersants and detergents.

A composition for an electrolytic capacitor and an electrolytic capacitor including the composition is provided. The composition includes an intrinsically conductive polymer and an electrolyte solution. The electrolyte solution includes an organic solvent, an ionic salt compound and a succinimide-based compound.

Various examples are provided related to functionalization for sensing of antibodies. In one example, a method for functionalizing a test strip includes cleaning a gold surface of an electrode of a test strip; submerging the cleaned gold surface in a 3-Mercaptopropanyl-N-hydroxysuccinimide ester solution; cleaning channels of the test strip; injecting an antibody into the channels; sealing the injected antibody in the test strip; storing the sealed test strip at a controlled temperature; and deactivating unfunctionalized groups. In another example, a method includes connecting a functionalized test strip to a strip connector; generating a test pattern that is passed through the functionalized test strip and input into a gate terminal of a MOSFET in a readout block; converting a readout signal into a frequency signal; and counting the frequency signal at fixed intervals to generate a counter output, and displaying a sample concentration based upon the counter output.

The present invention discloses an electrochemiluminescent compound, a preparation method thereof and an application thereof, wherein the structural formula of the electrochemiluminescent compound is: wherein n is 100-200, R1, R2, R3 and R4 are all selected from one of a Y group and a hydrogen group, and at least one of R1, R2, R3 and R4 is a Y group. The preparation method of the electrochemiluminescent compound comprises the following steps: dissolving an iridium-containing complex, N, N-diisopropylethylamine, N, N, N', N'-tetramethyl-O-(N-succinimide) urea tetrafluoroborate in N, N-dimethylformamide and mixing; adding a polyethyleneimine solution, performing an amide reaction, separating, and obtaining the electrochemiluminescent compound. The electrochemiluminescent compound (Ir-PEI) of the present invention can improve the water solubility of the iridium-containing complex, can also be used as a coreactant unit in the molecule to promote the generation of ECL signals, and can be used as an ECL active material to construct and prepare an iridium ECL reagent.

The invention relates to the technical field of chemical oil-displacing agents for tertiary oil recovery, and particularly discloses a magnetic nano oil-displacing agent and a preparation method thereof. The preparation method comprises the following steps: S1, taking purple phosphorus nanosheets, ferrous sulfate, ferric chloride and ammonia water as raw materials to react to obtain magnetic purple phosphorus nanosheets; s2, reacting the polymer A with ethylenediamine to obtain an aminated polymer A; s3, adding the aminated polymer A or polymer B and 4-dimethylaminopyridine 1, 3-dicyclohexylcarbodiimide into an aqueous solution of the magnetic purple phosphorus nanosheet, so as to obtain a modified magnetic purple phosphorus nanosheet; s4, performing ammonification reaction on the surfactant to obtain an aminated surfactant; and S5, adding an aminated surfactant into the modified magnetic purple phosphorus nanosheet aqueous solution, then adding N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride, and carrying out a reaction to obtain the magnetic nano oil displacement agent. The oil-displacing agent disclosed by the invention can realize magnetic recovery while realizing a viscosity reduction effect so as to improve the oil recovery rate, and waste of raw materials is avoided.

The application discloses an anticoagulant biomaterial for blood purification and a preparation method and application thereof, and comprises the following steps: providing an amphiphilic copolymer P(AA-MMA); blending polyethersulfone, P(AA-MMA) and a solvent, stirring at a set temperature to obtain a casting solution, and preparing a blending membrane from the casting solution; soaking the blending membrane in a 2-morpholine-4-yl ethanesulfonic acid buffer solution containing argatroban, 1-ethyl-(3-dimethylaminopropyl) carbonyl diimide and hydroxy succinimide, and reacting at room temperature to obtain an argatroban grafted blending membrane, namely the anticoagulant biomaterial. The method improves the hydrophilicity of the membrane, reduces the albumin adsorption of the membrane, reduces the adhesion of platelets on the membrane, prolongs the coagulation time APTT, PT and TT of the membrane, and is better in biocompatibility and enhanced in anticoagulation performance.

The application discloses a fuel oil stabilizer for high-viscosity residual oil blending. The fuel oil stabilizer comprises, in percentage by weight, 1-15% of a fatty amine, 0.1-1.5% of a mono-polyisobutene bis-succinimide, 0.1-2% of a non-ionic surfactant alkylphenol polyoxyethylene-polyoxypropylene alcohol ether, 1-30% of alkyl imidazole ionic liquid and / or quaternary ammonium salt ionic liquid, 10-30% of polyvinyl pyrrolidone, 10-20% of an antifoaming agent, and the rest of hydrogenated white oil. The stabilizer has good compatibility, dispersibility, aging resistance and thermal stability for high-viscosity residual oil blending fuel oil.

The invention is directed to a method for reducing low speed pre-ignition events in a spark-ignited direct injection internal combustion engine by supplying to the sump a lubricant composition which contains an oil of lubricating viscosity and an ashless dispersant. The ashless dispersant may be selected from succinimide compounds prepared from aliphatic or aromatic amines.

The invention relates to the field of slow-release fertilizers, in particular to preparation of a hydrogel slow-release fertilizer. The invention discloses a preparation method of a slow release fertilizer of polyaspartic acid, carboxymethyl cellulose hydrogel, stearic acid and urea. Comprising the following steps: (1) preparing polysuccinimide, (2) preparing a polyaspartic acid gel solution by using the polysuccinimide, and then preparing a polyaspartic acid / carboxymethyl cellulose hydrogel solution by using the polyaspartic acid gel solution; the method further comprises the following steps: (3) preparing stearic acid / urea particles; 4, the polyaspartic acid / carboxymethyl cellulose hydrogel solution and the stearic acid / urea granules are used for preparing and obtaining the polyaspartic acid-carboxymethyl cellulose hydrogel-stearic acid-urea slow-release fertilizer.By means of the method, the slow-release fertilizer with the dual functions of water retention and slow release can be prepared and obtained.