Instruction manual of human beta amyloid 1-40 (Aβ1-40) ELISA kit This kit is for research use only Intended application Quantitative determination of β-amyloid 1-40 (Aβ1-40) in human serum, plasma or other related fluids by ELISA. Experimental principle Coat the microplate with purified antibody to make a solid-phase carrier. Add specimens or standards, biotinylated anti-Aβ1-40 antibody, and HRP-labeled avidin to the monoclonal antibody-coated microwells in sequence. After washing, color was developed with the substrate TMB. TMB is converted into blue under the catalysis of peroxidase, and into the final yellow under the action of acid. The color depth is positively correlated with Aβ1-40 in the sample. The absorbance (OD value) was measured with a microplate reader at a wavelength of 450 nm, and the sample concentration was calculated. Kit composition and reagent preparation 1. ELISA plate: one piece (96 wells) Standard product (lyophilized product): 2 bottles, each of which is diluted with sample diluent to 1ml before use. After being capped, it is allowed to stand for more than 10 minutes. , After serial dilution, 300 pg / ml, 150 pg / ml, 75 pg / ml, 37.5 pg / ml, 18.8 pg / ml, 9.4 pg / ml, 4.7 pg / ml, and the sample dilution is The standard concentration is 0 pg / ml, prepared within 15 minutes before use. For example, to prepare a 150 pg / ml standard: Take 0.5ml 300 pg / ml of the above standard and add it to an Eppendorf tube containing 0.5ml of sample diluent, mix well, and so on for the remaining concentrations. 2. Sample diluent: 1 × 20ml / bottle. 3. Test the diluent A: 1 × 10ml / bottle. 4. Test dilution B: 1 × 10ml / bottle. 5. Detection solution A: 1 × 120ul / bottle (1: 100) diluted with detection dilution A 1: 100 before use, prepared according to the pre-calculated total amount required for each experiment before dilution (100ul per well) , The actual preparation should be more 0.1-0.2ml. For example, 1ul detection solution A plus 99ul detection dilution A is prepared in proportion, mix gently and prepare within one hour before use. 6. Test solution B: 1 × 120ul / bottle (1: 100) is diluted 1: 100 with test diluent B before use. The dilution method is the same as that of Test Solution A. 7. Substrate solution: 1 × 10ml / bottle. 8. Concentrated washing solution: 1 × 30ml / bottle, each bottle is diluted 25 times with distilled water. 9. Stop solution: 1 × 10ml / bottle (2N H2SO4). Collection and preservation of specimens 1. Cell culture supernatant: collect the supernatant after centrifugation, and store the specimen at -20 ℃, and avoid repeated freezing and thawing. 2. Serum: Please leave the specimen at room temperature for 2 hours or overnight at 4 ° C and centrifuge at 1000 xg for 20 minutes. Take the supernatant for testing, or store the specimen at -20 ° C, but avoid repeated freezing and thawing. 3. Plasma: EDTA or heparin can be used as an anticoagulant. Centrifuge the sample at 2-8 ° C 1000 xg for 15 minutes within 30 minutes after collection, or store the specimen at -20 ° C, but avoid repeated freezing and thawing. Note: The above specimens should be stored at 4 ° C for less than 1 week. For long-term storage, please store at -20 ° C in a sealed state, but it should not exceed 3 months; specimen hemolysis will affect the final test results, so hemolysis specimens should not be used Detection; specimens with high blood lipids do not require special treatment and can be directly detected. Steps Before starting the experiment, please configure all reagents in advance. When the reagents or samples are diluted, they should be mixed well. Try to avoid foaming when mixing. A standard curve should be made for each test. If the sample concentration is too high, dilute with sample diluent to make the sample meet the detection range of the kit. 1. Add sample: set blank hole, standard hole and sample hole to be tested respectively. Add 100ul of sample diluent to the blank well, and 100ul of the standard or the sample to be tested in the remaining well. Be careful not to have air bubbles. Add the sample to the bottom of the well of the microtiter plate. The target plate is covered with a cover or film and reacted at 37 ° C for 120 minutes. To ensure the validity of the experimental results, please use a new standard solution for each experiment. 2. Discard the liquid and spin dry without washing. Add 100ul of detection solution A working solution to each well (take 1ul of detection solution A plus 99ul of detection dilution A to prepare, mix gently and prepare within one hour before use), 37 ℃, 60 minutes. 3. After incubating for 60 minutes, discard the liquid in the hole, spin dry, wash the plate 3 times, soak for 1-2 minutes each time, 350ul / per hole, spin dry (you can also pat the liquid in the hole to pat dry). 4. Add 100 μl of testing solution B working solution (same as testing A working solution) to each well at 37 ℃ for 60 minutes. 5. After incubating for 60 minutes, discard the liquid in the hole, spin dry, wash the plate 5 times, soak for 1-2 minutes each time, 350ul / per hole, spin dry (you can also pat the liquid in the hole to pat dry). 6. Add 90ul of substrate solution to each well in sequence, and develop color at 37 ° C in the dark (within 30 minutes, at this time, the first 3-4 wells of the standard product have a visible blue gradient, and the latter 3-4 wells have no obvious gradient) , You can terminate). 7. Add 50ul of stop solution to each well in sequence to stop the reaction (in this case, the blue color turns to yellow). The order of adding the stop solution should be the same as that of the substrate solution. In order to ensure the accuracy of the experimental results, the termination solution should be added as soon as possible after the substrate reaction time expires. 8. Measure the optical density (OD value) of each well in sequence using an enzyme-linked instrument at a wavelength of 450 nm. Test within 15 minutes after adding stop solution. Note: 1. Leave one hole for each experiment as a blank zero adjustment hole (different from the blank hole). No reagents are added to this hole, but the substrate solution and 2N H2SO4 are added at the end. Use this hole to adjust the OD value to zero when measuring. 2. Incubate in strict accordance with the prescribed time and temperature to ensure accurate results. All reagents must reach room temperature before use. Refrigerate the reagent immediately after use. 3. Incorrect plate washing can lead to inaccurate results. Before adding test solution B or substrate, make sure to absorb the liquid in the well as much as possible. Do not let the microwells dry out during incubation. In order to prevent the sample from evaporating, place the reaction plate in a closed box covered with a damp cloth during the test. The microplate is covered with a cover or film. After the plate is washed and dried, please add the next step reagent immediately. Avoid drying the micropores. 4. Eliminate the residual liquid and fingerprints on the bottom of the board, otherwise it will affect the OD value. 5. Substrate coloring liquid should be colorless or very light color. Substrate liquid that has turned blue cannot be used. 6. Avoid direct light exposure during storage and incubation. 7. Store unused microplates or reagents at 2-8 ° C. Standard products, working solution A, and working solution B should be configured and used according to the required amount. Do not reuse the diluted standard, test solution A working solution or test solution B working solution. 8. It is recommended to set a double-hole test when testing samples to ensure the accuracy of the test results. Plate washing method Manual plate washing method: absorb (not to touch the wall) or shake off the liquid in the enzyme plate; place a few layers of water on the experimental table Paper, with the microtiter plate down and vigorously pat several times; inject at least 0.3ml of the recommended wash buffer into the well and soak for 1-2 minutes, as needed Yes, repeat this process several times. Specificity The kit can detect recombinant or natural human Aβ1-40 at the same time, and has no cross-reactivity with other related proteins. Calculation Taking the concentration of the standard as the abscissa (logarithmic coordinate) and the OD value as the ordinate (ordinary coordinate), draw a standard curve on semi-logarithmic coordinate paper, and find the corresponding concentration from the standard curve according to the OD value of the sample; Multiply by the dilution factor; or use the standard concentration and OD value to calculate the linear regression equation of the standard curve, substitute the OD value of the sample into the equation, calculate the sample concentration, and multiply by the dilution factor to obtain the actual concentration of the sample. Precautions 1. The washing process is very important. Insufficient washing can easily cause false positives. 2. It is best to control the sampling time within 5 minutes. If there are many specimens, it is recommended to use a volley gun to add samples. 3. Please make a standard curve at the same time of each measurement, and it is best to make a double hole. 4. If the content of the substance to be tested in the specimen is too high, please dilute it and then determine it. When calculating, please multiply by the dilution factor. 5. When preparing standard products and testing solution working fluids, please prepare with corresponding diluent, not to be confused. 6. Please keep the substrate away from light. examination range: 4.7 pg / ml -300 pg / ml Minimum detection limit: 2.4 pg / ml Explanation 1. Avoid exposing the reagent to strong light during storage and incubation. All reagent bottle caps must be tightly closed to prevent evaporation and contamination. Reagents should be protected from microbial contamination, because the interference of proteolytic enzymes will lead to erroneous results. 2. Aspirate the reagents carefully and strictly observe the given incubation time and temperature. Please note that when drawing samples / standards, enzyme conjugates or substrates, if the time interval between the first well and the last well is too large, it will result in different "pre-incubation" time, which obviously Affect the accuracy and repeatability of the measured value. Moreover, insufficient washing will affect the test results. 3. Storage of the kit: -20 ℃ (only for some reagents when not in use for a long time, see the label for details); 2-8 ℃ (when used frequently). 4. Validity: 6 months 5. Salt will be precipitated from the concentrated washing liquid, which can be heated and dissolved in the water bath when diluted. 6. The newly opened enzyme-linked plate well may contain a little water-like substance. This is normal and will not have any impact on the experimental results. 7. There may be inconsistencies between the Chinese and English instructions. Please refer to the English instructions. 8. All samples should be managed, and the samples and testing devices should be processed according to the prescribed procedures. Dining chair is a common seat in restaurants, bars, cafes and other places for people to use when dining. According to different design styles, materials, functions and uses, dining chairs can be divided into a variety of categories. The following will be a brief introduction to the product classification of dining chairs. Cafe chair,wholesale chair,stackable chair,connected chair Foshan Shengshi Zhihui Technology Co., Ltd. , https://www.zhhotelfurniture.com
Automatic plate washing: If there is an automatic plate washing machine, it should be used in the formal experiment process after being used skillfully.
First, according to the design style classification
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Second, according to the material classification
1. Wooden dining chair: Wooden dining chair is usually made of solid wood or artificial wood, with natural, environmental protection and warm characteristics, suitable for families and cafes and other places.
2. Metal dining chair: Metal dining chair is often made of metal materials such as iron, aluminum or stainless steel, with strong, durable and easy to clean characteristics, suitable for bars and cafes and other places.
3. Plastic dining chair: Plastic dining chair is usually made of polypropylene or polycarbonate and other plastic materials, with light, waterproof and easy to clean characteristics, suitable for fast food restaurants and school cafeterias and other places.
Third, according to the use of classification
Generally, it can be divided into two uses: domestic and commercial.
1. Home dining chair: Home dining chair pays attention to comfort and beauty, common dining table chair, folding chair and bar chair.
2. Commercial dining chairs: Commercial dining chairs pay attention to durability and practicality, common bar chairs, cafe chairs and fast food restaurant chairs.
In general: dining chair as one of the important furniture in restaurants, bars, cafes and other places, according to the design style, material and use of different, can be divided into a variety of categories. Choosing a dining chair that suits your place and needs can enhance the comfort and beauty of the dining environment.