Tween 20, solution preparation

Prepare each of two negative controls by filtering 50 ml of sterile 0.1% Tween solution. Place filter on sterile prepoured TSA plates as described previously. 

After collection and smear-section preparation, samples should be washed with PBS, fixed in 4% formaldehyde in phosphate-buffered saline (PBS), and p>ermeabilized for 10 min in PBS containing 0.25% Triton X-100. Immunocytochemical staining can be perform performed by incubating the samples with pritnaiy antibodies in PBS/Tween (PBS containing 0.1% Tween 20 and 3% BSA) for 1-2 hr, followed by incubation with appropriate secondary antibodies diluted according to the manufacturer s recommendation in PBS/Tween solution for 1-2 hr. Stained samples can then be visualized with confocal microscope. 

NTMT, pH 9.5 lOOmM NaCl, lOOmM Tris-HCl, pH 9.5, 50mM MgCl, 0.1% Tween-20 (prepared freshly on day of use from concentrated stock solutions of the individual components). 

Fuel emulsification. Emulsify 1 ml of fuel in 9 ml of Ringer s solution with Tween 80. Prepare serial dilutions of the emulsion in sterile phosphate buffer and pour or streak plate the dilutions. If the fuel is viscous, 0.1ml of fuel can be added to 0.2 ml of the emulsifying agent. Then add 9.7 ml sterile deionized water to make a 1 100 dilution. Plate this solution directly or prepare dilutions for plating on or with agar media. This method has a lower level of detection compared to the filtration method. 

Chloramphenicol, soluble 1 in 400 of water at 20° C and 1 in 7 of propylene glycol, has been solubilized in Tween solutions [92,93]. In spite of its superior solubility in propylene glycol, this compound cannot be used as a solvent for chloramphenicol in eye-drops or nasal preparations since it causes a marked burning sensation. Simple aqueous solutions of chloramphenicol lose about half their antibiotic activity by hydrolysis on storage for 290 days at 20 to 22° C [94]. 

The preparation and physical properties of oil/water microemulsions containing liquid paraffin, glycerol, water and blends of Tween 60 and Span 80 have been examined [180]. The decrease in micellar size as the surfactant/alcohol ratio was increased is similar to the situation observed with solubilized micellar solutions formed by non-ionic surfactants. Turbidity spectra methods of particle sizing have shown that an increase of temperature of preparation over the range 25 to 80° C led to a gradual decrease in the modal diameter and the half-width of the size distribution curve. Phase diagram studies on micellar solutions prepared at 70° C have indicated a pronounced dependence of the area of existence of microemulsions on the ratio of Tween to Span in the system and on the oil... 

Chitosan microparticles were prepared with tripolyphosphate by ionic cross-hnking, starting from chitosan acetate 1% and oil as an emulsion in the presence of the surfactant Tween-80 2% the o/w 1 10 emulsion was introduced into tripolyphosphate solution by a spray gun. The microparticles were then washed their sizes were in the 500-710 jim range. As the pH of tripolyphosphate solution decreased and the molecular weight of chitosan increased, the microparticles had a more spherical shape and smoother surface [98]. 

The multiple emulsion technique includes three steps 1) preparation of a primary oil-in-water emulsion in which the oil dispersed phase is constituted of CH2CI2 and the aqueous continuous phase is a mixture of 2% v/v acetic acid solution methanol (4/1, v/v) containing chitosan (1.6%) and Tween (1.6, w/v) 2) multiple emulsion formation with mineral oil (oily outer phase) containing Span 20 (2%, w/v) 3) evaporation of aqueous solvents under reduced pressure. Details can be found in various publications [208,209]. Chemical cross-linking is an option of this method enzymatic cross-linking can also be performed [210]. Physical cross-linking may take place to a certain extent if chitosan is exposed to high temperature. 

A spore suspension was prepared by resuspending the spores from the agar plate in 15 mL physiological aqueous solution (8.5 g NaCl, 1 g peptone, and 1 g Tween 80 in 1 L distilled water, sterilized at 121 °C for 20 min) with a Drigalski spatula. The spore suspension was diluted to a concentration of approximately 2.5 x lO spores/mL and stored in a 50 mL Falcon tube at 4 °C. 

Figure 9.17 Green fluorescent protein (GFP) synthesis in water-in-oil emulsion as visualized by fluorescence microscopy. (Adapted from Pietrini and Luisi, 2004). Shown are the compartments in which GFP has been expressed (green in the original), (a) Typical micrographs of the cell-free GFP synthesis in Span 80 (0.45% v/v)/Tween 80 (0.05% v/v)/aqueous solution (0.5% v/v) in mineral oil emulsion droplets, preparation at 4 °C incubation at 37°C (i) 0 min, (ii) 11 min, (iii) 23 min, (iv) 32 min, (v) 44 min, (vi) 57 min, (vii) 21 h. Negative control (viii) 0 min, (ix) 21 h. The bar represents 50 p.m. (b) Kinetics of the cell-free GFP synthesis in emulsion droplets, on average 10 droplets with diameters of 30-60 um are evaluated per time point, cell-free enhanced GFP synthesis in emulsion droplets (i, ii and iii are three independent experiments) and negative controi (iv and v are two independent experiments).

This product is an aqueous solution of water-soluble vitamins with oily vitamin A palmitate and cholecalceferol solubilized in water using the surfactant system of Tween 80 and Cetomacrogol. This syrup is a solubilized oil surfactant system and is liable to heat and rate of mixing. The temperature of solution must not exceed 30°C at the time of final mixing. The final mixing must be in continuous manner without any interruption. For the preparation of oily phase, the container must be dry. 

Slowly add 100 mL of 20% (v/v) Tween-20 (see Note 4) Leave to stir for 15 min 4. Add dropwise 4 mL of freshly prepared stannous chloride solution to the gold/ Tween mixture (see Note 5) The color of the solution will change from gold to burgundy Leave to stir for 5 min... 

Tween 20 solution 0.3% (v/v) Tween 20 in PBS (prepare solution fresh weekly and store at 4°C)... 

The emulsion was freshly prepared O) from 10 ml sunflower oil, 2 ml 30% aqueous solution of Tween 20, and 88 ml 0.1 M phosphate buffer at various pH values. This mixture was homogenized in a BIOMIX-mixer (LABOR MIM, Budapest) for 5 min. 

Aqueous solution of SWNTs was suspended with different types of surfactants a) anionic (SDS) (CH3(CH2)ii(S04) Na+), b) cationic (hexadecyltrimethylammonium bromide (CTAB) (CH3(CH2)i5N+(CH3)3Br) and c) and non-ionic (Tween-80) H(Et-0)n0(C4H602CH0HCH20 CO(Ci8H23). Surfactants SDS and CTAB were purchased from Serva , Tween-80 from Shuchard (Germany). 0.05 mg/mL nanotube dispersion with surfactant was mixed and then the suspension was sonicated for 40 minutes. A concentration of surfactants in water solution was 1%. Water was prepared by distillation and then passed through Multi-Q system. The deionized water has resistance 18 MO. 

Precautions should also be taken with the aqueous solvents used to prepare standard working solutions in order to avoid adsorption problems, especially at low concentrations. To minimize adsorption during standard curve and validation sample (VS)/QC preparations, aliquots of the high-concentration stock solutions should be spiked promptly into the control blank plasma to prepare the standards and VS/QC. Once the compounds are in an environment of protein solutions, the adsorption problem is negligible. If there is a problem, however, adding or pre-rinsing with a solution of protein or a chaotropic agent (e. g., Tween, Triton X-100 or CHAPS) may help to alleviate the problem. 

The standard incubation mixture contained 100 fiL of 0.25 M Tris-HCl buffer (pH 7.4) containing 1.75 mM palmitic add and 1% (w/v) Tween-20 50 /x.L of enzyme preparation (about 0.5 mg protein), and 50 tL of 80 or 100 nM zinc acetate solution. After incubating 5 minutes at 37°C, the reaction was started by adding 50 / L of 100 /iM mesoporphyrin or protoporphyrin. The incubation was continued for 30 minutes at 37°C in the dark. The reaction was stopped by adding 1 mL of ice-cold methanol-DMSO (8 2, v/v) containing 13 nM Zn-deuteroporphyrin as internal standard. The mixture was cooled on ice and centrifuged before analysis of the supernate by HPLC. The... 

Standard herbicidal formulations in the absence of surfactant were prepared by dissolving the highest intended dose of each TFMS compound in a 1% acetone-water solution. The small amount of acetone (necessary to effect solution of some of the more lipophilic series members) was used in all formulations for consistency. Standard herbicidal formulations in the presence of surfactant were prepared in a similar fashion, except that the 1% acetone-water contained in addition 0.1% (w/v) Tween 80. 

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