756 results about "Large molecular weight" patented technology

The invention relates generally to intradermal, transdermal, and / or transmembrane delivery of biologically active substances in the epidermis and / or through the skin, sub-dermal tissues, blood vessels and cellular membranes without causing damage to the cellular surface, tissue or membrane. The biologically active substances may have a molecular weight no less than about 5.8 kDa to about 2,500 kDa, such as Hyaluronic Acid (HA). The biologically active substances may be deposited in a dermal patch containing a red algae polysaccharide-based matrix, wherein the red algae polysaccharide is an extract of Chondrus crispus at 2% by weight of the dermal patch. The invention provides systems and methods for enhanced intradermal, transdermal, and / or transmembrane delivery of such biologically active substances using pulsed incoherent light. The invention further provides a device for the application of the pulsed incoherent light to cellular surfaces and membranes using those compositions and methods.

A matrix is disclosed including a core showing a system of micropores and a surface in which the micropore system has openings. The characterizing feature is that the surface is coated with a polymer (I) having such a large molecular weight that it cannot penetrate into the micropores.

A fine particle comprising an amphiphilic polymer, further comprising an inner nucleus of hydrophilic segment of amphiphilic polymer, and a hydrophobic outer layer of hydrophobic segment of amphiphilic polymer, and having a surface modifier bonded to the hydrophobic outer layer.A fine particle of the invention effectively enclose protein, peptide drug, nucleic acid medicine of hydrophilic property and large molecular weight in the inner nucleus of hydrophilic segment of amphiphilic polymer, and are preferable for stabilizing in the body and promoting absorption.

Garbage and waste of all types that includes or comprises organic matter, particularly including medical waste, plastics, paper, food waste, animal by-products, and the like, can be economically recycled into petroleum products, including oil. Machinery performs a method that mimics natural processes but accomplishes the task in minutes, at rates of about 15 tons per day in a typical processing machine, rather than taking hundreds of thousands of years in nature. The process and apparatus of the invention may chop the waste into small pieces, under negative pressure if appropriate, and then pass the waste into first and then second augers for compression and heating. Destructive distillation occurs, in which large molecular weight hydrocarbons and petrochemicals are heated by hot oil passing through the hollow shaft and by circulating hot, dense, hard material, such as steel balls or fragments or hard rock pieces and such, under pressure with steam, to produce low molecular weight hydrocarbons. The volatile hydrocarbons are released through a pressure relief valve, into a column of catalyst material, and then to a heat exchanger, which cools the gases to condensation temperatures of water and oil. Gases remaining, such as methane, are passed to a furnace or other use, and the water and oil are separated. The hot items used to put heat into the compressed material in the first stage auger are retrieved after processing is completed and then reheated and cycled back into the first stage auger.

Whole blood is treated extracorporeally to remove substances contrary to health using mesoporous / microporous or macroporopus / microporous carbon in the form of beads or a channel monolith. The carbon may be the result of carbonising a mesoporous or macroporous phenolic resin. Substances contrary to health include externally introduced toxins such as bacterially derived staphylococcus enterotoxins A, B, TSST-1 or autologous, biologically active molecules with harmful, systemic effects when their activity is excessive or unregulated. Examples include the removal of inappropriate amounts of pro- or anti-inflammatory molecules and toxic mediators of systemic inflammatory response syndrome related to sepsis, cardio-pulmonary by-pass surgery, ischaemic reperfusioninjury; the removal of larger molecular weight and protein bound uremic toxins related to kidney and hepatic toxins related to liver failure and the removal of toxins relevant to biological and chemical warfare.

Dye-peptide conjugates useful for diagnostic imaging and therapy are disclosed. The dye-peptide conjugates include several cyanine dyes with a variety of bis- and tetrakis(carboxylic acid) homologues. The small size of the compounds allows more favorable delivery to tumor cells as compared to larger molecular weight imaging agents. The various dyes are useful over the range of 350-1300 nm, the exact range being dependent upon the particular dye. Use of dimethylsulfoxide helps to maintain the fluorescence of the compounds. The molecules of the invention are useful for diagnostic imaging and therapy, in endoscopic applications for the detection of tumors and other abnormalities and for localized therapy, for photoacoustic tumor imaging, detection and therapy, and for sonofluorescence tumor imaging, detection and therapy.

The invention discloses a de-emulsifying agent and a method for preparing the same. The de-emulsifying agent is a polyether compound prepared by alkoxylation reaction of poly (amidoamine) (PAMAM) and epoxy compounds. The invention adopts the PAMAM with a dendritic multi-branch structure as an initiator for synthesis the de-emulsifying agent. The obtained de-emulsifying agent has the characteristics of a plurality of branched and large molecular weight. The de-emulsifying agent has good interfacial activity, infiltrability, good crude oil emulsion de-emulsifying performance, and wide applications in crude oil exploration, oil refining and other fields.

The invention discloses macromolecule weight urethane acrylate, which is formed by reaction on the basis of aliphatic polyester diatomic alcohol with the molecular weight of 500 to 8000, aliphatic diisocyanate and hydroxy acrylic acid monomer; wherein, polyesterglycol comprises ring-shaped resin, and the mechanical property and hydrolysis resistance property of light curing film are improved. The molecular weight of synthetic resin is 10000 to 50000 units, and acrylic ester double keys on the two ends of molecule chain enable the resin to produce high-efficiency free radical aggregation linkage under the effect of photoinitiators through the radiation of ultraviolet light. The aggregation linkage product of the finished film has good flexility and adhesive force, extremely low light curing contraction percentage, higher tensile strength and breaking elongation with hydrolysis resistance property improved. The invention can be used as the main ingredient or assistant matieral of light curing paint, light curing printing ink and light curing adhesive.

The invention discloses long-chain branched polyester and a preparation method thereof. The long-chain branched polyester is obtained by carrying out esterification and polycondensation on a diacid component A, a diacid component B and a bifunctional branching agent component C such as biglycidyl ester, diglycidyl ether or glycidol and the like. According to the invention, a non-toxic bifunctional branching agent is directly adopted to in situ generate branching points; the preparation method is unique, preparation process is simple and environmentally-friendly, branching reaction is uniform,branching degree is easy to regulate and control, and the high molecular weight long-chain branched polyester can be prepared; and the preparation method can be used for preparation of non-degradablepolyester and preparation of biodegradable polyester, thereby being beneficial to the realization of commercialization. The long-chain branched polyester has the characteristics of long-chain branching and large molecular weight in structure and is beneficial to increase of melt strength and improvements of blow molding and foaming processing performance.

The invention relates to a method for preparing a waterproof and moisture permeable finishing agent of a polyurethane fabric. Raw materials for the preparation method comprise polyether polyol, vulcabond, and a chain extender, wherein the polyether polyol comprises polyether diol with a molecular weight of between 2,000 and 3,000 and polyether triol with a molecular weight of between 3,000 and 4,000; and the chain extender comprises an ion chain extendor. In the raw materials for the preparation method, the hydrophilic polyether triol with larger molecular weight substitutes the prior small molecular polylol, polyamine or polycarboxylic acid to introduce the internal crosslinking into a polyurethane soft segment phase so as to ensure that a synthesis reaction is easy to control and simultaneously consider the crystallinity, the moisture permeability and the waterproofness of polyurethane. The method overcomes the contradiction of crystallization / crosslinking and waterproofness / moisture permeability caused by adopting the small molecular polylol, polyamine or polycarboxylic acid as a crosslinking agent.

The present invention relates to a powdery composition for nasal administration, which is characterized in that (1) the composition contains (i) a drug, (ii) a water-absorbing and gel-forming base material such as hydroxypropyl cellulose or hydroxypropylmethyl cellulose and (iii) a water-absorbing and water-insoluble base material such as crystalline cellulose or alpha-cellulose, (2) wherein the amount of the water-absorbing and gel-forming base material is about 5-40 wt % based on the total of the water-absorbing and gel-forming base material and the water-absorbing and water-insoluble base material, and (3) wherein the drug is unevenly dispersed more on / in the water-absorbing and water-insoluble base material than on / in the water-absorbing and gel-forming base material. The present invention provides the powdery composition for nasal administration excellent in absorption of the drug from the nasal cavity and having an extremely increased maximum blood concentration comparing a conventional composition for nasal administration even for a drug having a high solubility in water, a drug having a high lipophilicity or a peptide / proteinaceous drug having a large molecular weight.

The present invention relates to a polymerizable macromolecule photoinitiator and a preparation method thereof. The preparation method comprises: adding 4-hydroxybenzophenone and a formaldehyde solution to a three-necked flask filled with an alkali adopted as a catalyst, carrying out heating stirring to a temperature of 95 DEG C, and carrying out a reaction for 2 hours; heating to a temperature of 150 DEG C, carrying out a reaction, and carrying out a reduced pressure suction filtration reaction for 20 minutes; cooling to a temperature of 105 DEG C after completing the reaction, and collecting the product; pouring the product into water to carry out precipitation, and carrying out suction filtration to obtain a benzophenone-containing macromolecule photoinitiator; dissolving the benzophenone-containing macromolecule photoinitiator in an organic solvent, and simultaneously adding the benzophenone-containing macromolecule photoinitiator and a tertiary amine to the three-necked flask to carry out stirring; dissolving acryloyl chloride in an organic solvent, and slowly adding the organic solvent containing the acryloyl chloride to the mixing solution in a dropwise manner, wherein thereaction temperature is 0-5 DEG C; after completing the addition, stirring for 3 hours at a room temperature, and standing overnight; carrying out suction filtration, washing and drying on the resulting solution; and carrying out rotary evaporation to remove the solvent to obtain the polymerizable macromolecule photoinitiator. The photoinitiator prepared by the preparation method of the present invention has characteristics of large molecular weight, relatively small mobility, self-polymerization, and the like.

The invention provides waterborne polyurethane resin for waterborne clothing leather base and a preparation method thereof. The waterborne polyurethane resin comprises the following raw materials (by weight): 70-85 parts of macromolecular polyol, 10-20 parts of polyisocyanates, 1.5-3.5 parts of a hydrophilic chain-extender, 0.5-2 parts of a micromolecular alcohol chain-extender, 6-25 parts of an amine chain-extender, 0.01-0.5 part of a catalyst and 2-5 parts of a salt forming agent. By the use of the ether-bonded macromolecular polyol with large molecular weight, the waterborne polyurethane resin has low modulus modulus and soft hand-feeling. The amine chain-extender used in the invention is polyetheramine. In comparison with other amine chain-extenders, main chain of polyetheramine is a polyether structure such that waterborne polyurethane feels softer; and polyetheramine has large molecular weight such that solid content of the waterborne polyurethane resin is greatly enhanced so as to raise fullness of the waterborne polyurethane resin.

A dialyzer module utilizing a nano-porous ceramic membrane for enhanced hemodialysis performance, and a method for manufacturing the same, are provided. The dialyzer module may be utilized in an extracorporeal blood circuit together with pumps, monitors, and / or other components used for dialysis therapy. The one or more nano-porous ceramic tubes that serve as the hemodialysis membrane may comprise aluminum oxide (alumina) or titanium oxide (titania) tubes manufactured by the anodization of aluminum (Al) or titanium (Ti) tubes in an appropriate acid solution. The nano-porous ceramic tubes may be produced with a nano-porous wall structure having an average pore diameter of approximately five to ten nanometers (run). The nano-porous ceramic tubes exhibit a uniform pore size, uniform pore distribution, high porosity, and high hydraulic conductivity, enabling the removal of more middle and large molecular weight solutes to achieve a performance more comparable to that of an actual kidney while, at the same time, reducing the undesirable loss of important macromolecules such as albumin.

The invention discloses a macromolecular polymerizable photoinitiator and a preparation thereof. The method comprises the following steps of: adding 4-hydroxybenzophenone and methanal to a three-necked flask, heating to 95 DEG C, reacting for 2 hours, heating to 150DEG C, leaching under at reduced pressure for 20 minutes, cooling to 105 DEG C, collecting products, pouring products into water, leaching to obtain a macromolecular photoinitiator, dissolving the macromolecular photoinitiator in an organic solvent, dissolving epoxy chloropropane in the solvent under catalysis of boron trifluoride,dropwise adding mixed liquid, reacting at a temperature of 0-5 DEG C, then stirring for 3 hours at a temperature of 70 DEG C, removing epoxy chloropropane and solvent, dissolving residues with a solvent, adding alkali and reacting for 0.5 hour at a temperature of 40 DEG C, removing salt and the solvent, re-dissolving residues with a solvent, washing with water and drying, adding crylic acid, p-hydroxyanisole and tetrabutylammonium bromide, heating for reacting for 6 hours, and then removing the solvent so as to obtain macromolecular polymerizable photoinitiator. The macromolecular polymerizable photoinitiator prepared by the method has the advantages of large molecular weight, weak mobility and good polymerizability.

The invention discloses a bicyclic phosphate-based triazine derivative flame retardant and a preparation method thereof. The flame retardant is prepared by the condensation polymerization of cyanuric chloride and 1-oxide-4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo [2,2,2] octane. The preparation method has the advantages of easy acquisition of raw materials and simple operation. The prepared flame retardant contains a carbon source, an acid source and a foaming source, greatly exerts the advantages of the PEPA and the triazine structure in flame retardant applications, is favorable for exerting the synergistic flame retardant action of nitrogen and phosphorus, and can effectively improve the defects of the traditional compound flame retardant. The bicyclic phosphate-based triazine derivative flame retardant has large molecular weight, has the advantages of high heat stability, good migration resistance and the like, and can be used as a single intumescent flame retardant (IFR) or can be compounded with other components to form an IFR system to be applied to material flame retardant modification.

Cyanine and Indocyanine dye compounds and bioconjugates are disclosed. The present invention includes several cyanine and indocyanine dyes, including bioconjugates of the same, with a variety of bis- and tetrakis (carboxylic acid) homologues. The compounds of the invention may be conjugated to bioactive peptides, carbohydrates, hormones, drugs, or other bioactive agents. The small size of compounds of the invention allows favorable delivery to tumor cells as compared to larger molecular weight imaging agents. Further, use of a biocompatible organic solvent such as dimethylsulfoxide may be said to assist in maintaining the fluorescence of compounds of the invention. The compounds and bioconjugates herein disclosed are useful in a variety of medical applications including, but not limited to, diagnostic imaging and therapy, endoscopic applications for the detection of tumors and other abnormalities, localized therapy, photoacoustic tumor imaging, detection and therapy, and sonofluorescence tumor imaging, detection and therapy.

The invention discloses a cyanate ester composition. Specifically, the cyanate ester composition comprises cyanate ester, low-molecular weight polyphenylene oxide / polyphenylene ether, an olefin monomer, an organic metal salt catalyst, an inorganic filling material, an environmental-friendly fire retardant and an organic solvent. The invention also discloses copper-clad plates made of the cyanate ester composition, and a method used for preparing the copper-clad plates by the cyanate ester composition. Low-molecular weight polyphenylene oxide / polyphenylene ether which is obtained by redistribution reaction is used in the cyanate ester composition, so that a problem of poor fluidity of large-molecular weight polyphenylene oxide / polyphenylene ether is solved; in addition, the olefin monomer is added for further improvement of compatibility of the system, and dielectric properties of the system are not influenced. The cyanate ester composition can be used for preparation of the high-performance copper-clad plates which are green and friendly to the environment. The copper-clad plates possess excellent dielectric properties, heat resistance and environmental-friendly fire resistance.

The invention discloses a waterborne polyurethane acrylate emulsion and waterborne plastic ink prepared by the same. During an emulsifying process of polyurethane prepolymer, an amino chain extender is used to extend the chain and seal the end, then polyurethane prepolymer is reacted with isocyanate acrylate to introduce double bonds, and finally graft acrylate, thus preparing the waterborne polyurethane acrylate emulsion. The obtained waterborne polyurethane acrylate emulsion has large molecular weight of polyurethane segment, improves the mechanical property of waterborne polyurethane acrylate, has both the flexibility of polyurethane and the excellent adhesive force on PET and NY, and has both the good water resistance of polyacrylate and the adhesive fastness of PP; no emulsifier exists in the waterborne polyurethane acrylate emulsion, thus an excellent dispersion effect on pigments is obtained and the waterborne polyurethane acrylate emulsion can be used as grinding resin to prepare mill base. The waterborne polyurethane acrylate emulsion can be used for preparing waterborne plastic ink, the prepared waterborne plastic ink is non-toxic and odorless, good in resolubility, good in water resistance, has excellent adhesive force on substrates such as PP, PET and NY, has strong release force and can be applied to plastic packaging composite ink.

The invention discloses a plant fiber based solid amine adsorption material, a preparation method and application thereof. The adsorption material has a structural formula shown as the specification, wherein R is remaining group of lignin, and R1 is (CH2CH2NH)n, and n=1, 2, 3, 4, 5. The adsorption material takes plant fiber containing lignin and cellulose as the matrix, a classification modification method is employed, and an amine compound with a small molecular weight (less than 250g / mol) and a polyethylenimine polymer with a large molecular weight (greater than or equal to 1800g / mol) are respectively introduced to plant fiber's lignin and cellulose, thus obtaining the adsorption material. The adsorption material has good antibacterial performance and adsorption trapping performance to acid gas, and can be regenerated by thermal desorption after adsorption of acid gas.

The invention relates to high-temperature-resistant thermoset shape memory polyimide and a preparing method of the high-temperature-resistant thermoset shape memory polyimide. The method solves the problems that according to an existing method, thermoset SMP with the Tg larger than 230 DEG C cannot be prepared and currently-prepared polyimide is poor in thermal stability, mechanical property and shape memory performance. The structural formula of the polyimide can be seen in the specification. The preparing method comprises the steps that 1, a diamine solution is prepared; 2, polyamide acid with the large molecular weight of the anhydride seal end is prepared; 3, thick sol gel is prepared; 4, the high-temperature-resistant thermoset shape memory polyimide is prepared. The Tg of the prepared high-temperature-resistant thermoset shape memory polyimide ranges from 235 DEG C to 245 DEG C, the shape memory effect of the high-temperature-resistant thermoset shape memory polyimide is guaranteed, and the high-temperature-resistant thermoset shape memory polyimide can be applied to the high temperature field.

The present invention provides a mass spectrometer capable of breaking even a sample molecule having a large molecular weight by a CID process. In an embodiment of the present invention, the mass spectrometer includes an ionizing source 10 for turning a sample into ions, mass-separating sections 40 and 60 for mass-separating the sample ions, a detecting section 20 for detecting the mass-separated ions, and a collision section (collision cell) 51 located on an ion path extending from the ionizing source 10 through the mass-separating sections 40 and 60 to the detecting section 20. It also includes a cluster generator 30 for producing clusters of atoms or molecules. The clusters produced by the cluster generator 30 are introduced into the collision cell 51. The use of the clusters having a huge mass as the target gas in the CID process enables the collision energy of the sample ions to be efficiently assigned to the breaking of the ions.

The invention relates to a fractional extraction method for honey pomelo peel polysaccharides, a product thereof and application of the product, and provides a method for preparing a tobacco humectant from honey pomelo peels. According to the invention, the honey pomelo peel polysaccharides are extracted by taking honey pomelo peels as raw material and combining high-speed shear emulsification method with complex enzyme two-stage cell wall-breaking method, the honey pomelo peel polysaccharides are fractionated using different solvents by means of organic solvent temperature-variable penetration and precipitation, and the difference in molecular weight distribution of fractionated polysaccharides is investigated by means of gel chromatography. The molecular weight determination of different fractionated polysaccharides shows that there is a significant difference in molecular weight of polysaccharides which are fractionated using different solvents, wherein the weight-average molecular weight of the peak (1) of crude polysaccharide a is 24100 Da, the weight-average molecular weight of the peak (1) of crude polysaccharide b is 11700 Da, and the weight-average molecular weight of the peak (1) of crude polysaccharide c is 2130 Da. As is indicated that the lower the ethanol concentration, the larger molecular weight of the precipitated polysaccharides. The optimum water-retaining concentration of pomelo peel polysaccharides is 1.5 g / 100 ml. When different solvents are selected, the water-retaining effects of pomelo peel polysaccharides are different, and the water-retaining effect of water-soluble pomelo peel polysaccharides is significantly higher than that of alcohol-soluble pomelo peel polysaccharides. In general, the water-retaining effects of both water-soluble pomelo peel polysaccharides and alcohol-soluble pomelo peel polysaccharides are better than those of propylene glycol and other humectants used in the prior art.

The invention discloses modified triethanolamine, a preparation method thereof and various grinding aids produced by using the modified triethanolamine. The modified triethanolamine is a cross mixed ester product produced through the chemical reaction of triethanolamine, inorganic mixed acid and catalyzer at a temperature. Grinding aid intensifier in powdered form, aqueous liquid form and nonaqueous liquid form is prepared by effectively compounding the product with other components. The triethanolamine is converted into the cross mixed ester having large molecular weight, thus reducing the cost by about 30 percent; the modified triethanolamine is applicable for powder grinding process at high temperature. The cement grinding aid intensifier prepared by compounding triethanolamine with other materials has better grinding aid effect compared with such conventional grinding aids which are used separately as triethanolamine and so on, improves the early strength of cement and reduces the consumption of wrought material; the materials used are cheap, and are stored and transported easily. The multiform products (powdered and in liquid state) are widely applicable in the cement industry.

The invention discloses a polyester film, and a preparation method and applications thereof. The polyester film is prepared by adopting processes of casting and setting and comprises the following components according to the weight ratio: 300-1200ppm of antiblocking inorganic additive and the balance polyethylene glycol terephthalate or modified resin with the intrinsic viscosity being more than 0.78dL / g. In the invention, the defects in the prior art are overcome, and the advantages of low degree of orientation, high elongation at break (up to 480%), good toughness for long time, large molecular weight and narrow distribution are realized. The polyester film has the characteristics of good adhesiveness on metal, low lining temperature, good deep-punching processing resistance, excellent printing effect, low small-molecular mobility and the like and has wide use prospect in the industries such as metal package and flexible package.

The invention improves the extraction yield of algae essence by using cellulase for decomposing cellulose in algae after dry algae which is ground and desanded is soaked in water and subjected to colloid mill treatment, and then leads alginic acid with large molecular weight to be degraded to alginic acid with small molecular weight by using alginate lyase, thus leading effective compositions in algae to be less damaged and having high extraction yield.

A synthetic method of a phosphorus-nitrogen intumescent flame retardant relates to a synthetic method of a flame retardant, which comprises the following steps: respectively dissolving raw materials of dichlorophenylphosphine and 4,4'-diaminodiphenylmethane in solvents, introducing inert gas, stirring, slowly and dropwisely adding the 4,4'-diaminodiphenylmethane solution into the dichlorophenylphosphine solution, after dropwise addition, performing reflux reaction for 2-10 hours, cooling, performing suction filtration, washing, and drying to obtain the light yellow powdery phosphorus-nitrogen intumescent flame retardant; the phosphorus-containing monomer and the nitrogen-containing monomer are combined into one compound through condensation polymerization reaction, and thus the flame retardant not only has good flame retardation, but also has the greatest advantage of good compatibility with polymer due to its large molecular weight. The compound can be used as a flame retardant additive for various polymers to improve the flame retardation of the polymers. According to the invention, the production process condition is simple; the product purity and yield are high; and the post-treatment process is simple.

The invention belongs to the field of chemical synthesis and particularly relates to a high-resilience polyurethane elastomer compound which is composed of two components including a prepolymer and a curing agent. Diisocyanate, polyether polyol and low-molecular-weight dihydric alcohol react with each other at 70 DEG C to 90 DEG C through polyether polyol to obtain the prepolymer with content of isocyanato ranging from 4.0% to 7.0%. 3,3'-dichloro-4,4'-diaminodiphenyl-methane is adopted as the curing agent. After mixed, the two components undergo vulcanization at the die temperature of 100-120 DEG C to obtain a high-resilience polyurethane elastomer product which is good in mechanical property and resilience. The high-resilience polyurethane elastomer compound has the advantage that ordinary polyether polyol is adopted to produce the high-resilience polyurethane elastomer compound. The polyether polyol with large molecular weight and the polyether polyol with small molecular weight are matched to be used, spaces among the molecules are increased appropriately, and the polyurethane elastomer product with the resilience larger than 40% is obtained.

The invention discloses a preparation method of carbon quantum dot by using chitosan through microwave, and application of the carbon quantum dot in biology medicine field. The method comprises the following steps that the high molecular weight chitosan is taken as the raw material, the microwave high temperature one-step synthesis method is adopted for preparing the carbon quantum dot with high quantum yield, and the surface passivation for the hydrophilia polyethylene glycol (PEG) is assisted to obtain the biology / medicine imaging quantum dot with high imaging capability, good water solubility, low cost and light-resistance quenching capability. The raw material is easy to obtain and the preparation process is simple and convenient, the carbon quantum dot has excellent optical property and is specially applied to the biomedical tracking and imaging field.