scholarly journals Brewster angles for a dissipative film structure

2020 ◽  
Vol 63 (6) ◽  
pp. 672-679
Author(s):  
A. B. Sotsky ◽  
S. S. Miheev ◽  
M. M. Nazarov
Keyword(s):  
Aqueous Solution ◽  
Analytical Solution ◽  
Dissipative Structure ◽  
Protein Concentration ◽  
Film Structure ◽  
Thz Spectroscopy ◽  
Reflection Coefficients ◽  
Measurement Sensitivity ◽  
Film Substrate ◽  
Absorbing Substrate

The conditions of converting the reflection coefficients of plane TM or TE for a film-substrate dissipative structure are determined. As a result, the possibilities to maximize the measurement sensitivity by the THz spectroscopy method of the protein concentration in an aqueous solution are established, and the analytical solution to the inverse optical problem of determining the complex permittivity and thickness of a weakly absorbing film located on a weakly absorbing substrate is obtained.

scholarly journals Obtaining human hair keratin-based films and their characteristics

2021 ◽  
Vol 15 (1) ◽  
pp. 27-36
Author(s):  
V. V. Mykhaliuk ◽  
◽  
V. V. Havryliak ◽  
Keyword(s):  
Molecular Weight ◽  
Disulfide Bonds ◽  
Protein Concentration ◽  
Sodium Dodecyl ◽  
Protein Composition ◽  
Surface Characteristics ◽  
Film Structure ◽  
X Ray ◽  
Wide Range ◽  
Scanning Electron

Background. Keratins are natural biopolymers with a wide range of applications in the field of biotechnology. Materials and Methods. Extraction of keratins was performed by a modified Nakamura method using 250 mM DTT. The protein concentration in the supernatant was determined by Bradford method. The protein composition was studied by their electro­phoretic separation in a polyacrylamide gel in the presence of sodium dodecyl sulfate. The films were made by casting. The surface characteristics of the films were determined using a scanning electron microscope REMMA-102. The elemental composition of the films was determined using an X-ray microanalyzer. Results. The protein concentration in the supernatant was 3.75 mg/mL. After using dithiothreitol in the extraction mixture, we obtained proteins of intermediate filaments with a molecular weight of 40–60 kDa and a low Sulfur content. In the low molecular weight region, we obtained keratin-associated proteins with a molecular weight of 10–30 kDa and a high content of Sulfur. These proteins belong to fibrillar proteins, which can be used as a matrix for the creation of new keratin-containing biocomposites with a wide range of applications in reparative medicine and tissue engineering. Based on the obtained keratin extract, polymer films with and without the addition of glycerol were made. Scanning electron microscopy revealed that glycerol provided the film structure with homogeneity and plasticity due to the accumulation of moisture after the fixation by water vapor. The X-ray microanalysis of films revealed such elements as Sodium, Silicon, Sulfur, Potassium. Among the detected elements, Sulfur has the largest share that is due to the large number of disulfide bonds in the keratin molecule. Conclusions. The polymer keratin films with the addition of glycerol demonstrated better mechanical properties and can be used in biomedicine.

scholarly journals Mathematical model of the process of ultrafiltration concentration of secondary milk raw materials in tubular membrane devices with filtering elements of BTU 05/2 type

2021 ◽  
Vol 83 (1) ◽  
pp. 36-43
Author(s):  
D. A. Rodionov ◽  
S. I. Lazarev ◽  
D. N. Protasov ◽  
O. A. Abonosimov ◽  
K. K. Polyansky
Keyword(s):  
Mathematical Model ◽  
Analytical Solution ◽  
Protein Concentration ◽  
Cheese Whey ◽  
Raw Materials ◽  
Experimental Studies ◽  
Transmembrane Pressure ◽  
Specific Output ◽  
Output Flow ◽  
Mathematical Equations

For the qualitative application of ultrafiltration processes for the concentration and purification of food solutions, both experimental studies and a mathematical description of the processes of the membrane separation process of solutions from the standpoint of the development of computational mathematical models are required. In this work, by analytical solution of equations, that is, by the method of finite differences, mathematical equations are solved. To obtain the system, the flow continuity equations, convective diffusion equations, Navier-Stokes equations and flow equations with boundary conditions were solved in order to build a mathematical model of the process of ultrafiltration protein concentration in cheese whey in the production of rennet cheeses. As a result of the analytical solution of the equations, a system of mathematical equations was obtained that allows one to construct a profile of changes in the flow rates of the solution along the cross-section of the intermembrane channel and to determine the protein concentration in cheese whey along the length of the tubular ultrafiltration element BTU 05/2 of industrial type. The obtained mathematical model makes it possible to theoretically describe the process of ultrafiltration protein concentration in cheese whey along the entire length of the membrane channel of the tubular element under laminar and transient regimes of solution flow. The resulting system of mathematical equations makes it possible to find the numerical values of the mass flow rate of cheese whey, make it possible to calculate the specific output flow when the transmembrane pressure changes and to calculate the concentration of solutes in the secondary milk raw materials on the left and right ultrafiltration membrane of the intermembrane channel. The adequacy of the developed mathematical model was carried out by comparing the calculated and experimental data on the specific output flow when the transmembrane pressure in the intermembrane channel changes from 0.1 to 0.25 MPa with ultrafiltration concentration of cheese whey. The deviation of the calculated data found by the mathematical model from experimental studies obtained on a semi-industrial tubular ultrafiltration plant BTU 05/2 using semipermeable membranes, in which the active layer is made of fluoroplastic, hemisulphone and polyethersulfone, did not exceed 10%.

Effects of hypoproteinemia on lung microvascular protein sieving and lung lymph flow

1986 ◽  
Vol 60 (4) ◽  
pp. 1293-1299 ◽  
Author(s):  
R. E. Parker ◽  
N. E. Wickersham ◽  
R. J. Roselli ◽  
T. R. Harris ◽  
K. L. Brigham
Keyword(s):  
Total Protein ◽  
Protein Concentration ◽  
Lymph Flow ◽  
Reflection Coefficients ◽  
Base Line ◽  
Total Protein Concentration ◽  
Total Proteins ◽  
Osmotic Reflection Coefficient ◽  
Lung Lymph ◽  
Lung Lymph Flow

Experiments were conducted on five chronically instrumented unanesthetized sheep to determine the effects of sustained hypoproteinemia on lung fluid balance. Plasma total protein concentration was decreased from a control value of 6.17 +/- 0.019 to 3.97 +/- 0.17 g/dl (mean +/- SE) by acute plasmapheresis and maintained at this level by chronic thoracic lymph duct drainage. We measured pulmonary arterial pressure, left atrial pressure, aortic pressure, central venous pressure, cardiac output, oncotic pressures of both plasma and lung lymph, lung lymph flow rate, and lung lymph-to-plasma ratio of total proteins and six protein fractions for both control base-line conditions and hypoproteinemia base-line conditions. Moreover, we estimated the average osmotic reflection coefficient for total proteins and the solvent drag reflection coefficients for the six protein fractions during hypoproteinemia. Hypoproteinemia caused significant decreases in lung lymph total protein concentration, lung lymph-to-plasma total protein concentration ratio, and oncotic pressures of plasma and lung lymph. There were no significant alterations in the vascular pressures, lung lymph flow rate, cardiac output, or oncotic pressure gradient. The osmotic reflection coefficient for total proteins was found to be 0.900 +/- 0.004 for hypoproteinemia conditions, which is equal to that found in a previous investigation for sheep with a normal plasma protein concentration. Our results suggest that hypoproteinemia does not alter the lung filtration coefficient nor the reflection coefficients for plasma proteins. Possible explanations for the reported increase in the lung filtration coefficient during hypoproteinemia by other investigators are also made.

scholarly journals THE ADSORPTION OF EGG ALBUMIN ON COLLODION MEMBRANES

1936 ◽  
Vol 19 (6) ◽  
pp. 907-916 ◽  
Author(s):  
Philip Dow
Keyword(s):  
Aqueous Solution ◽  
Experimental Study ◽  
Isoelectric Point ◽  
Protein Concentration ◽  
Adsorption Behavior ◽  
Adsorption From Solutions ◽  
Egg Albumin ◽  
Alkaline Side

An experimental study has been made of the adsorption of purified egg albumin, from aqueous solution, on collodion membranes. At protein concentrations of 4 to 7 per cent apparent saturation values were obtained which resembled closely the results obtained with gelatin, showing a maximum at pH 5.0 and lower values on either side of this region. Over large ranges of protein concentration, however, the curves for the adsorption from solutions removed in either direction from the isoelectric point exhibited a different shape from the hyperbola obtained in the neighborhood of pH 5.0. The addition of NaCl to solutions on the acid side tended to obliterate the effect of the pH difference; on the alkaline side it greatly increased the adsorption. The adsorption at 25° was about twice as great as that at 1°. The theory of the swelling of submicroscopic particles, advanced to account for the adsorption behavior of gelatin, is not sufficient to explain the results obtained with egg albumin. It is suggested that the effect is related to alterations in the forces causing the retention of the protein on the membranes.

scholarly journals Probing Local Electrostatics of Glycine in Aqueous Solution by THz Spectroscopy

2020 ◽  
Author(s):  
Federico Sebastiani ◽  
Chun Yu Ma ◽  
Sarah Funke ◽  
Alexander Bäumer ◽  
Dominique Decka ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Thz Spectroscopy

CHROMIUM-RICH COATINGS WITH WS2 NANOPARTICLES CONTAINING FULLERENE-LIKE STRUCTURE

NANO ◽  
2011 ◽  
Vol 06 (04) ◽  
pp. 313-324 ◽  
Author(s):  
O. EIDELMAN ◽  
H. FRIEDMAN ◽  
R. ROSENTSVEIG ◽  
A. MOSHKOVITH ◽  
V. PERFILIEV ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Stainless Steel ◽  
Palladium Nanoparticles ◽  
Friction And Wear ◽  
Pure Metal ◽  
Trivalent Chromium ◽  
Growth Promoters ◽  
Low Friction ◽  
Film Substrate ◽  
Steel Substrates

In this work chromium-rich coatings impregnated with fullerene-like (IF)-WS2 nanoparticles were deposited on stainless steel substrates. The coatings were obtained from a trivalent chromium bath at pH 2 by galvanostatic electrodeposition. Zinc and cobalt salts were added to the aqueous solution in small amounts serving as cationic growth promoters. Photodeposition of tin-palladium nanoparticles was used as seeding enhancer for the co-deposition of the fullerene-like nanoparticles. The coatings were characterized by a number of techniques and were found to show a decreasing gradient of the IF nanoparticles towards the film-substrate interface. Tribological tests showed that in contrast to the substrate and the pure metal coating, the IF-containing films exhibit low friction and wear.

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