Dry-film method

E226 Polz-Schaerffenberg, E. and Barnes, J.L. (1985). Automated dry-film method evaluated for total bilirubin in serum. Clin. Chem. 31, 1923-1924. 

Cationic liposomes composed of 3(3- [ N- (N N-dimethylaminoethane (carbamoyl] cholesterol (DC-Chol) and dioleoylphosphatidylethanolamine (DOPE) (DC-Chol/DOPE liposome, molar ratio, 1 1 or 3 2) prepared by the dry-film method have been often used as non-vtral gene delivery vectors. We have shown that a more efficient transfection in medium with serum was achieved using DC-Chol/DOPE liposomes (molar ratio, 1 2) than those (3 2), and preparation method by a modified ethanol injection than the dry-film. The most efficient DC-Chol/DOPE liposome for gene transfer was molar ratio (1 2) and prepared by a modified ethanol injection method. The enhanced transfection is related to an increase in the release of DNA in the cytoplasm by the large lipoplex during incubation in opti-MEM 1 reduced-serum medium (optiMEM), not to an increased cellular association with the lipoplex. Cationic liposomes rich in DOPE prepared by a modified ethanol injection method will help to improve the efficacy of liposome vector systems for gene delivery. 

Notably, liposomes composed of 3 -[N- N N -dimethylaminoethane)carbamoyl)cholesterol (DC-Chol) together withdioleoylphosphatidylethanolamine (DOPE) (DC-Chol/ DOPE liposome) have been classified as one of the most efficient vectors for the transfection of DNA into cells (8-10) and in clinical trials (11, 12). It has been demonstrated that a 3 2 or 1 1 molar ratio of DC-Chol/DOPE liposome results in high transfection efficiency (10). In these cases, liposomes are mostly prepared by the dry-film method. To further improve the transfection efficiency, it is necessary to evaluate DC-Chol/DOPE liposome from formulation and preparation method of liposome to formation method of their lipoplex. 

We reported that greater transfection efficiency in medium with serum was obtained in human cervical carcinoma HeLa cells, using (I) DC-Chol/DOPE liposomes (molar ratio, 1 2) than liposomes (1 1 or 3 2), (2) a modified ethanol injection (MEI) method to prepare liposomes than the dry-film method (13, 14), and (3) a dilution method to form lipoplex than direct mixing. The physicochemical properties of liposomes and lipoplexes can be examined by measuring particle size. Transfection efficiency was evaluated by using plasmid DNA encoding luciferase gene and the cells. 

Determine the infrared spectium of fhe sublimed camphor and compare it to the spectrum provided in the experiment (use the dry film method in Technique 25, Section 25.4 or other method recommended by your instructor). The spectrum should demonstrate complete oxidation to camphor (absence of OH peak and presence of C=0 peak). There should be sufficienf material for the reduction of camphor to isoborneol. Part B. At the option of fhe instructor, determine the H and NMR spectra of your camphor. Also, at the option of the instructor, determine the melting point (literature mp about 177°C, but it is often lower than this value). Store the camphor in a tightly sealed vial. 

Determine the infrared spectrum of the benzoin by the dry film method (Technique 25, Section 25.4). A spectrum is shown here for comparison. 

Weigh the dry benzil and calculate the percentage yield. Determine the melting point. The melting point of pure benzil is 95°C. Submit the benzil to the instructor unless it is to be used to prepare benzilic acid (Experiment 32C). Obtain the infrared spectrum of benzil using the dry film method. Compare the spectrum to the one shown. Also compare the spectrum with that of benzoin. What differences do you notice ... 

At the option of the instructor, obtain the infrared spectrum using the dry film method (Technique 25, Section 25.4) or as a KBr pellet (Technique 25, Section 25.5) and the NMR spectrum in CDCI3 (Technique 26, Section 26.1). Submit the sample in a labeled vial to the instructor. 

The reaction requires about 1 week for completion (3 hours with a sunlamp). If the reaction has occurred during this period, the product will have crystallized from the solution. Observe the result in each test tube. Collect the product by vacuum filtration using a small Buchner or Hirsch funnel (Technique 8, Section 8.3) and allow it to dry. Weigh the product and determine its melting point and percentage yield. At the option of the instructor, obtain the infrared spectrum using the dry film method (Technique 25, Section 25.4) or as a KBr pellet (Technique 25, Section 25.5). Submit the product to the instructor in a labeled vial along with the report. 

Using a Craig tube, recrystallize the crude product from hot 95% ethanol. Allow the crystals to dry. Weigh the dried crystals, calculate the percentage yield, and determine the melting point (literature value is 90-91 °C). Determine the infrared spectrum of the product using the dry film method. Determine the proton NMR spectrum of the product in CDCI3 solution. 

Solid Samples. The easiest way to hold a solid sample in place is to dissolve the sample in a volatile organic solvent, place several drops of this solution on a salt plate, and allow the solvent to evaporate. This dry film method can be used only with modern FT-IR spectrometers. The other methods described here can be used with both FT-IR and dispersion spectrometers. A solid sample can also be held in place by making a potassium bromide pellet that contains a small amount of dispersed compound. A solid sample may also be suspended in mineral oil, which absorbs only in specific regions of the infrared spectrum. Another method is to dissolve the solid compound in an appropriate solvent and place the solution between two sodium chloride or silver chloride plates. 

A simple method for determining the infrared spectrum of a solid sample is the dry film method. This method is easier than the other methods described here, it does not require any specialized equipment, and the spectra are excellent. The disadvantage is that the dry film method can be used only with modern FT-IR... 

AppHcation of an adhesion-promoting paint before metal spraying improves the coating. Color-coded paints, which indicate compatibiHty with specific plastics, can be appHed at 20 times the rate of grit blasting, typically at 0.025-mm dry film thickness. The main test and control method is cross-hatch adhesion. Among the most common plastics coated with such paints are polycarbonate, poly(phenylene ether), polystyrene, ABS, poly(vinyl chloride), polyethylene, polyester, and polyetherimide. 

Type of paint Method of application Coats Dry film thickness (litn)... 

Nanocarbon hybrids have recently been introduced as a new class of multifunctional composite materials [18]. In these hybrids, the nanocarbon is coated by a polymer or by the inorganic material in the form of a thin amorphous, polycrystalline or single-crystalline film. The close proximity and similar size domain/volume fraction of the two phases within a nanocarbon hybrid introduce the interface as a powerful new parameter. Interfacial processes such as charge and energy transfer create synergistic effects that improve the properties of the individual components and even create new properties [19]. We recently developed a simple dry wrapping method to fabricate a special class of nanocarbon hybrid, W03 /carbon nanotube (CNT) coaxial cable structure (Fig. 17.2), in which W03 layers act as an electrochromic component while aligned... 

To achieve the mechanical strength needed for use as a membrane, a microporous polyethylene support was used. The support, obtained from 3M (Minneapolis, MN), was approximately 20 microns in thickness and was 83% porous. The liquid monomer mixtures were applied to the support with a wiped film method and subsequently polymerized with UV irradiation at 365 nm and 2.0 mW/cm2 for 2 hours. After polymerization, a solid transparent film was obtained. To allow unreacted monomer and oligomer to leave the film, it was placed into chloroform for three days, with fresh chloroform exchanges once per day. After the chloroform exchanges, the film was allowed to dry in the chemical hood. 

For hydroxypropyl methylcellulose acetate succinate, a novel enteric dry coating method has been developed [31]. The unique feature of this method is that the enteric polymer is added in powder form (e.g., mixed with talcum directly to tablets or pellets) whereas a plasticizer diluted with paraffin is sprayed separately. The tablet core temperature is around 40°C, and the film is cured for a short time. To achieve a homogenous film, the rates of powder feeding and plasticizer spray have to be adjusted such that the two processes start and end simultaneously. 

Samples of BMI dried using variable humidity were analyzed by SEM and the degree of film cracking was calculated using image analysis software (Table 2). Controlled humidity drying at 60 or 70°C provided nearly crack free amorphous TiC>2 films (Method 1). Crystalline films (Method 2) needed to be dried at 70°C. Controlled humidity drying of the amorphous films at elevated... 

Films. Both structural and nonstructural adhesives are commonly available in film form. Adhesives applied in the form of dry films offer a clean, hazard-free operation with minimum waste and excellent control of film thickness. However, the method is generally limited to parts with flat surfaces or simple curves. Optimum bond strength requires curing under heat and pressure, which may involve considerable equipment and floor space, particularly for large parts. Film material cost is high in comparison to liquids, but waste or material loss is the lowest of any application method. 

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