294results about How to "Improves pH stability" patented technology

An aqueous composition having increased protein stability is obtained by: a. determining a pH at which the protein has stability at the desired temperature; b. adding to the composition at least one displacement buffer wherein the displacement buffer has a pKa that is at least 1 unit greater or less than the pH of step (a); and c. adjusting the pH of the composition to the pH of step (a); wherein the aqueous composition does not comprise a conventional buffer at a concentration greater than about 2 mM and wherein the conventional buffer has a pKa that is within 1 unit of the pH of step (a).

A culture dish (1) comprising a basic structure (2) with a number of macro wells (4) for culturing oocytes and embryos, the culture dish further comprising a lid (3) with a movable part (8), the movable part (8) having an opening (11) adapted to the size of the macro wells (4), the movable part (8) being movable between a first position where all macro wells are closed by the lid (3) and further positions where for each further position (11) the opening (11) is aligned with one of the macro wells (4) to allow access to this macro well (4) through the opening (11) in the lid (3).

The invention discloses a method for preparing a water-oil repellent fluorine-containing textile finishing agent, comprising the following steps of: adding a fluorine-containing alkyl (methyl) acrylate monomer, a higher fatty alcohol (methyl) acrylate monomer, a cross-linking monomer, an emulsifying agent, a solvent, a chain transfer agent and the like into a container in sequence, dropwise adding deionized water at 30-80 DEG C, shearing at high speed for pre-emulsification, carrying out high-pressure homogenization or ultrasound on a pre-emulsified solution, adding an initiator, and polymerizing for 0.5-8h at 50-80 DEG C. The obtained finishing agent has small particle size, uniform polymer composition and favorable properties of mechanical stability, pH stability, chemical stability, dilution stability and storage stability, and contains no components such as PFOS/PFOA (Perfluorooctane Sulfonates/Perfluorooctanoic Acid) and the like harmful to human bodies, and textiles finished with the finishing agent have favorable water-oil repellent property and has lower cost in comparison with like products.

A composition and method for treating a fracturing fluid comprising produced water with high levels of dissolved solids using a polymer crosslinked with a boron compound and a high pH alkylamine buffer. The composition improves the viscosity stability of the fracturing fluid at elevated bottom-hole temperatures, particularly when the fluid has high levels of calcium and magnesium. The composition is particularly useful with polysaccharides, including galactomannan gums, such as guar gum, locust bean gum, and karaya gum, and allows for the use of the preferred boron compound crosslinkers in high total dissolved solids fracturing fluids without the pH destabilization problems encountered with the prior art.

The invention discloses an acid-resistant and alkali-resistant waterborne damping coating with a wide temperature range and high damping capacity, comprising, by weight, 30-65 parts of a waterborne emulsion, 15-45 parts of a filler, 10-35 parts of a flame retardant, 0.1-2 parts of fibers, 0-5 parts of a film-forming agent, 0.1-1.5 parts of a dispersing agent, 0.1-1.5 parts of a defoaming agent, 0-4 parts of an antifreeze agent, 0.2-3 parts of a thickening agent and 1-8 parts of a multifunctional aid. The acid-resistant and alkali-resistant waterborne damping coating with wide temperature region and high damping capacity has the advantages that the acid-resistant and alkali-resistant waterborne damping coating is high in damping performance, wide in damping temperature range and excellent in acid resistance and alkali resistance; loss factors of materials in the temperature range ranges from -30 DEG C to 50 DEG C reach 72 hours as shown by acid-resistant and alkali-resistant tests on the materials by the aid of 10% NaOH solution and 10% H2SO4 solution, and the acid-resistant and alkali-resistant waterborne damping coating is free of foaming, softening and sticking and excellent in acid resistance and alkali resistance.

The invention relates to a micro emulsion cutting fluid composition and a preparation method thereof. The composition comprises the following raw materials in percentage by weight: 22-32 mineral oil, 2-10 anionic surfactant, 1-5 nonionic surfactant, 1-3 emulsion stabilizer, 5-10 oiliness additive, 5-10 extreme pressure additive, 5-15 rust-inhibiting additive, 0.5-3 anticorrosion fungicide, 0.1-0.3 antifoam additive and the balance of water. The preparation method of the micro emulsion cutting fluid composition is simple and convenient, the provided cutting fluid S50 composition is an ecological stable product and has good lubricity and cooling performance, and the machining accuracy of workpieces can be improved. The cutting fluid S50 composition has strong antimicrobial capability, long service life and good PH value stability and provides good rust-inhibiting performance for the workpieces.

The invention provides a fluorine-containing waterproofing agent for textiles and a method for preparing the same, belonging to the chemical material field. A self-emulsifying fluorine-containing acrylate block copolymer is synthesized by means of ARGETATRP (Activators Regenerated by Electron Transfer for Atom Transfer Radical Polymerization); and the self-emulsifying fluorine-containing acrylate block copolymer can be directly used after being emulsified and diluted. The self-emulsifying fluorine-containing acrylate block copolymer prepared by the method has excellent pH stability, chemical stability, diluting stability and storage stability; and the fluorine-containing structure units are distributed in form of blocks on the polymeric chain of the fluorine-containing acrylate block copolymer so that the fluorine-containing chain segments can be effectively utilized. Compared with a random fluorocarbon resin, the fluorine-containing acrylate block copolymer is capable of achieving the same performance and the usable amount of fluorine-containing monomers is very low. Moreover, textiles finished by the fluorine-containing waterproofing agent have excellent waterproofness; and compared with the similar products, the fluorine efficiency is improved and the cost is reduced.

The invention provides a SOD gene from animal and a method for cloning and expressing the SOD gene in colibacillus and yeast cells, wherein a nucleotide sequence of superoxide dismutase is shown as SEQ NO.1; an amino acid sequence of the superoxide dismutase is shown as SEQ NO.2; carriers of nucleotide molecules are colibacillus plasmids or yeast plasmids; cells of the nucleotide molecules are formed by carrier conversion; and cells of the nucleotide molecules of the superoxide dismutase contain colibacillus containing the nucleotide molecules or converted by the carriers or pichia yeast containing the nucleotide molecules or converted by the carriers. The invention can prepare recombinant production strains which can efficiently express and secrete Cu/Zn-SOD, realizes the production industrialization of the Cu/Zn-SOD, and achieves good pH stability, favorable thermal stability and Cu/Zn-SOD products with anti-protease hydrolyzation capacity.

The invention discloses a preparation method for a super-hydrophobic metal surface. The method comprises the following steps: constructing a micrometer structure on the surface of a frequently used engineering material (such as copper, iron, stainless steel, nickel, aluminum, an aluminum alloy and a high-molecular section covering the above-mentioned metal through chemical plating) by using an electrocoppering process; then constructing a nanometer structure by using a chemical silvering process; and carrying out modification with low-surface energy substances like octadecanethiol so as to obtain excellent and stable super-hydrophobicity. The method has a wide application scope and can be used on pure metal, alloys and metalized high-molecular sections; an obtained surface has stable and reliable surface performance, strong film-substrate bonding force and good corrosion resistance, especially good acid resistance, can be extensively applied in fields like self-cleaning, water prevention and dehumidification, corrosion prevention, fluid drag reduction, frost prevention and condensation and heat exchange, and has an industrialization value.

The invention discloses a method for preparing yellow or green carbon dots. The method comprises the following steps: (1) dispersing a carbon source, a passivator and a reducer into ultrapure water, and stirring under the protection of protective gas to obtain a mixed solution; (2) performing heating reaction on the mixed solution obtained in the step (1) in a reaction container to obtain a carbondot solution; and (3) directly placing the carbon dot solution obtained in the step (2) into an ultrafiltration pipe or mixing the carbon dot solution and an organic reagent, and then centrifuging and drying to obtain the solid carbon dots. Based on the synergistic effect of the passivator and the reducer, the green or yellow carbon dots with high quantum yield are further synthesized by a simpleaqueous phase method, the carbon dots with different emitting wavelength can be synthesized by adjusting the mass ratio of the carbon source to the passivator to the reducer, the quantum yield of thegreen carbon dots is 22.5 percent and the quantum yield of the yellow carbon dots is 18.4 percent.

The invention provide a disperse dye monomeric compound which has a structure as represented by formula (I) in the specification. A disperse dye preparation prepared from the disperse dye monomeric compound provided by the invention can be used for dyeing materials which have been made into fine particles and are in a state of liquid or emulsifiable paste or for powdery and granular materials which have been dried by using a spray-drying process; when the disperse dye preparation prepared in the invention is used for dyeing a hydrophobic fibrous material, the advantages of a wide scope of applicable pH values, good reproducibility, a strong deep dyeing property, high color yield, good uniformity, and in particular, excellent color fastness to washing and ironing are obtained.

A method for manufacturing a composition including: mixing a basic material with a pigment dispersion including at least a pigment and water; and then subjecting the mixture of the basic material and pigment dispersion to a heat treatment. This composition is useful as an inkjet ink composition. An inkjet ink composition including at least pigment, water and a basic material, and has a pH of from 6.5 to 11.0 is also provided. An image forming method including discharging the composition from a nozzle to form an ink image on a receiving material is provided.

The invention discloses a mannanase and the coding gene, a recombinant vector and a host cell comprising the gene, and expression of the recombinant vector in E.coli and production of the enzyme in yeast cells by using the recombinant vector. The present invention also provides a new wild type subspecies of Bacillus Megaterium, in particular, Bacillus Megaterium FB101.

The present invention relates to a prefilled plastic container, such as a plastic syringe, comprising an aqueous botulinum toxin formulation. The aqueous botulinum toxin formulation in the prefilled plastic container is stable for a prolonged time period. Furthermore, the present invention relates to a kit comprising the prefilled plastic container, and to the use of the prefilled plastic container for therapeutic and cosmetic purposes.

The invention discloses an embedding and co-immobilization method of aldehyde ketone reductase and glucose dehydrogenase. The method includes the steps that the aldehyde ketone reductase and the glucose dehydrogenase are mixed and then added to a sodium alginate aqueous solution to be stirred and mixed evenly, then the mixture is dropwise added to a Cacl2 aqueous solution, the mixture is made to stand in a refrigerator at the temperature of 4 DEG C, washing is conducted through distilled water, vacuum filtration is conducted, and immobilized particles are obtained. Compared with free aldehyde ketone reductase, the catalytic activity of the co-immobilized enzyme prepared through the method is increased by 1.32 times, the heat stability, the PH stability and other performance of the co-immobilized enzyme prepared through the method are improved as well, and meanwhile, the cost is lowered due to reuse of the co-immobilized enzyme.

The invention relates to the field of gene engineering, in particular to alkaline pectinase poly lactic acid (PLA) and a gene and application thereof. According to the alkaline pectinase PLA, the amino acid sequence of the alkaline pectinase PLA is show as the sequence identity number 1 or 2 (SEQ ID NO. 1 or 2). The optimum potential of hydrogen (pH) for alkaline pectinase is 9.0, and more than 80% of enzymatic activity exists between pH 7.5 to pH 10.0. The alkaline pectinase PLA has good pH stability and is stabilized between the pH5.0 to pH10.5. Specific activity of the alkaline pectinase PLA is 797U/mg, and the alkaline pectinase PLA is good in alkaline protease resistance and easy in industrial fermenting production. Serving as a novel enzyme preparation, the alkaline pectinase PLA has application values in the industries of textile, papermaking, detergent, plant fiber processing, tea and coffee fermentation, oil extraction, treatment of industrial waste water containing pectin, biological technology and the like.

A marine streptomyces viridochromogenes strain for producing alkali-tolerant and salt-tolerant xylanase and application of the marine streptomyces viridochromogenes strain belong to the field of biotechnology. The strain is collected in the China General Microbiological Culture Collection Center, and the collection number is 5565. The strain can normally grow under the extreme alkaline environment of pH11, shows a good oligotrophy-tolerant characteristic, can degrade a variety of hemicellulose-containing biomasses including corn straws, rice straws, Jerusalem artichoke straws, kelp fibers andthe like, and has a broad application prospect in utilizing cheap biomass resources to produce bio-based chemicals. The strain can produce xylanase under optimum conditions, and the enzymatic activity of the xylanase can be as high as 68.9U/ml. The produced xylanase has the following properties: the optimum pH value is 6.0, the optimum temperature is 70 DEG C, the optimum substrate is beech xylan, and the produced xylanase does not have cellulase activity, has high pH stability and thermal stability, and can tolerate high-concentration NaCl. As an enzyme preparation coming from the ocean, thexylanase can be widely used in papermaking, food, feed, wine making, energy and other industries.

The invention discloses a microwave-assisted co-immobilization method of aldehyde ketone reductase and glucose dehydrogenase. The method includes the steps that a carrier and a crosslinking agent are mixed and activated, centrifuging is conduced, sediments are taken and washed through a PBS solution, centrifuging is conducted, and the sediments are re-dispersed in the PBS solution; the aldehyde ketone reductase and the glucose dehydrogenase are added to a dispersed solution, the mixed liquid is irradiated at the temperature of 0 DEG C to 10 DEG C under the 20-45 W microwave condition for 1 min to 5 min, centrifuging is conducted, sediments are taken and washed through the PBS solution, and co-immobilized enzyme is obtained; compared with free enzyme, the catalytic activity, heat stability and PH stability of the co-immobilized enzyme prepared through the method are improved; the glucose dehydrogenase serves as a coenzyme regeneration system of the glucose dehydrogenase to provide NAD(P)H required by a reaction, the cost is lowered, and industrial production is facilitated.

The invention relates to preparation and application of mesoporous silica/polyacrylonitrile core-shell nano-fiber films loaded with carbon quantum dots. A method includes preparing mesoporous silica/polyacrylonitrile core-shell nano-fiber film materials loaded with the carbon quantum dots from polyacrylonitrile nano-fiber films, tetraethylortho silicate and the carbon quantum dots by the aid of a sol-gel process. The preparation and the application have the advantages that mesoporous silica/polyacrylonitrile core-shell nano-fiber film materials can be applied to selective fluorescence detection on Fe3+ in water, are good in pH (potential of hydrogen) stability and high in photo-bleaching resistance and are perfect sensitive materials applicable to preparing thin-film type sensing devices.

The invention discloses a (Bacillus) A50 CGMCC No. 5744 and a method of producing hyaluronidase by employing the same. The method is that slant cultivation, seed cultivation and fermentation cultivation are carried out for the (Bacillus) A50 CGMCC No. 5744 so that hyaluronidase is prepared. The hyaluronidase generated by the Bacillus is highly active, up to 105IU/m1. As compared with the prior art, the hyaluronidase prepared from the Bacillus of the invention is high in activity, high in thermal stability and high in pH stability, and can be used for large scale production. Meanwhile, the obtained hyaluronidase can allow high-molecular hyaluronic acid to be degraded, can be used for preparing low-molecular hyaluronic acid and oligomeric hyaluronic acid, enables the cost to be substantially reduced, helps to solve the problem of high cost for hyaluronidase of animal sources, and exhibits a wide application prospect in the field of biochemistry research and for the production of low-molecular hyaluronic acid and oligomeric hyaluronic acid.

The invention aims to provide a preparation method of a hydrophobic lipophobic fluorine-containing acrylic acid cation/non-ionic surfactant emulsion. The preparation method comprises the steps of: mixing copolymerization monomers with cationic surfactant quarternary ammonium salt, a non-ionic surfactant Peregal O and an initiator to obtain a pre-emulsion under high shearing condition, and allowing copolymerization with N-methylol acrylamide. The cation/non-ionic surfactant emulsion is obtained by using a high-speed shearing machine, so that the mechanical void effect makes the reactants to reach nanometer scale. The polymerization rate is stable and the composition distribution of the polymer is uniform. The inventive surfactant emulsion has good mechanical stability, pH stability, chemical stability, dilution stability, and storage stability. The textile post-treated by the inventive emulsion has excellent hydrophobic, lipophobic and anti-fouling properties.

The invention relates to a preparation method of an organic-inorganic hybrid cyclodextrin chiral separation porous monolithic material. The preparation method comprises the following steps that an alkenylsilane coupling agent and an alkoxysilane coupling agent are mixed and are subjected to prehydrolysis; and the hydrolysate is added with alkenyl-containing cyclodextrin or a derivative of the alkenyl-containing cyclodextrin and an organic polymerization reaction initiator so that the alkenylsilane coupling agent and the alkoxysilane coupling agent undergo a polycondensation reaction in situ and the derivative of the alkenyl-containing cyclodextrin and the alkenylsilane coupling agent undergo a radical polymerization reaction in situ, and thus the organic-inorganic hybrid cyclodextrin chiral separation porous monolithic material with specific cyclodextrin derivative groups is obtained. The preparation method provided by the invention has simple processes, allows mild reaction conditions, can adopts different alkenyl-containing cyclodextrin derivatives according to different requirements, and realizes preparation of the organic-inorganic hybrid cyclodextrin chiral separation porous monolithic material.