scholarly journals STUDIES ON THE ANOMALOUS VISCOSITY AND FLOW-BIREFRINGENCE OF PROTEIN SOLUTIONS

1944 ◽  
Vol 27 (4) ◽  
pp. 355-399 ◽  
Author(s):  
Mary Dainty ◽  
Arnost Kleinzeller ◽  
A. S. C. Lawrence ◽  
Margaret Miall ◽  
Joseph Needham ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Cell Structure ◽  
Relative Viscosity ◽  
Flow Birefringence ◽  
Protein Solutions ◽  
Muscle Physiology ◽  
Anomalous Viscosity ◽  
Full Effect ◽  
Competitive Inhibitors ◽  
Other Substances

1. An investigation of the physicochemical properties of myosin has been carried out. Prepared under standard conditions, the ratio of flow-birefringence to protein concentration is uniform. The effect of electrolytes, pH, and urea on the flow-birefringence and viscosity (relative and anomalous) of myosin has been examined. 2. Decrease or abolition of flow-birefringence does not necessarily imply far reaching denaturation, since such effects can be reversed by a variety of means. 3. When a myosin solution is treated with adenosinetriphosphate, its flow-birefringence is decreased (average 48 per cent), its anomalous viscosity is retained, and its relative viscosity is decreased (average 14 per cent). The full effect of adenosinetriphosphate is obtained at 0.004 M; a molarity very much less than that of other substances which decrease the flow-birefringence of myosin. 4. The changes in the physicochemical properties of myosin brought about by adenosinetriphosphate are spontaneously reversible, and are connected with the enzymatic action of the protein as adenosinetriphosphatase. 5. Effects similar to those of adenosinetriphosphate on the physicochemical properties of purified myosin have been obtained so far only with inosinetriphosphate. 6. Inorganic phosphate is split off by myosin from inosinetriphosphate as well as from adenosinetriphosphate. Inorganic triphosphate is split by 1 to 2 per cent solution of three times precipitated myosin. 7. Adenosinediphosphate and inorganic triphosphate act as competitive inhibitors with adenosinetriphosphate, blocking the fall of flow-birefringence. 8. The implications of the results, and the conception of active enzymic groups attached to proteins participating in cell structure, whether contractile or non-contractile, are discussed in relation to present views on muscle physiology and other biological problems.

scholarly journals STUDIES ON THE ANOMALOUS VISCOSITY AND FLOW-BIREFRINGENCE OF PROTEIN SOLUTIONS

1944 ◽  
Vol 27 (3) ◽  
pp. 233-271 ◽  
Author(s):  
A. S. C. Lawrence ◽  
Margaret Miall ◽  
Joseph Needham ◽  
Shih-Chang Shen
Keyword(s):  
Film Flow ◽  
Surface Film ◽  
Mosaic Disease ◽  
Flow Birefringence ◽  
Bulk Phase ◽  
Protein Solutions ◽  
Amphibian Embryo ◽  
Anomalous Viscosity ◽  
Group A ◽  
Group B

1. An extensive investigation has been made of protein particle shape using the methods of flow-birefringence and anomalous viscosity measurement in the coaxial cell. 2. As a result of investigations on a number of proteins, it is concluded that they may be divided into four groups. Group A consists of those which show flow-anomaly both in the bulk phase and in the surface film. These also show flow-birefringence in the bulk phase. Examples: tobacco mosaic disease virus nucleoprotein; myosin. Though corpuscular proteins, they have elongated particles before denaturation. Group B consists of those which show flow-anomaly only (in the first instance) in the surface film, and no flow-birefringence in the bulk phase. They are probably close to spherical in shape in solution, but form elongated particles as they denature in the surface film. After this process has been completed, they may show flow-anomaly also in the bulk phase. Some proteins show flow-anomaly in the surface film immediately it forms, others only show it after a certain time has elapsed for the building up of the film. We designate the former as group B1 and the latter as group B2. Group B1, immediate surface film flow-anomaly. Examples: serum euglobulin, amphibian embryo euglobulin b. Group B2, slowly appearing surface film flow-anomaly. After the film has once been fully formed and then dispersed by shaking, the solution may have the properties of that of a protein in group B1; i.e., anomalous flow in the film may occur immediately on testing in the viscosimeter. Examples: avian ovalbumin, amphibian embryo pseudoglobulin. Group C consists of those proteins which show flow-anomaly neither in the bulk phase nor in the surface film, under the conditions used by us. They are probably close to spherical in shape. Examples: insulin, methaemoglobin, amphibian embryo euglobulin c, mucoproteins. 3. The theoretical significance of protein fibre molecules, whether native or formed by denaturation in the living cell, is discussed, especially in relation to experimental morphology and cytology.

scholarly journals STUDIES ON THE ANOMALOUS VISCOSITY AND FLOW-BIREFRINGENCE OF PROTEIN SOLUTIONS

1944 ◽  
Vol 27 (3) ◽  
pp. 201-232 ◽  
Author(s):  
A. S. C. Lawrence ◽  
Joseph Needham ◽  
Shih-Chang Shen
Keyword(s):  
Simultaneous Determination ◽  
Surface Film ◽  
Flow Birefringence ◽  
Bulk Phase ◽  
Protein Solutions ◽  
Dilute Solutions ◽  
General Behaviour ◽  
Anomalous Viscosity

1. A coaxial viscosimeter which permits the simultaneous determination of relative and anomalous viscosity and of flow-birefringence is described. Flow-anomaly and flow-birefringence are regarded as characteristic of elongated micelles and molecules. 2. Such methods have been applied to dilute solutions of proteins. The conditions under which the coaxial (Couette) viscosimeter measures the viscosity of the bulk phase and the surface film phase respectively have been investigated and are described. 3. The general behaviour of protein solutions subjected to shear is summarised.

Comparison of physicochemical properties of edible vegetable oils commercially available in Bahir Dar, Ethiopia

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Physicochemical Properties ◽  
Vegetable Oils ◽  
Relative Viscosity ◽  
Acid Value ◽  
Smoke Point ◽  
Refractive Indices ◽  
Bahir Dar ◽  
Icp Oes ◽  
Saponification Value ◽  
Oil Sunflower

The physicochemical properties of six imported and one locally produced edible vegetable oils (soybean oil, sunflower oil, sunlit oil, hayat oil, avena oil, USA vegetable oil and Niger oil) purchased from Bahir Dar city, Ethiopia, were examined for their compositional quality. All the oil samples were characterized for specific gravity, moisture content, color, relative viscosity, refractive indices, ash content, peroxide value, saponification value, smoke point, acid value, free fatty acid value and trace metals contents using established methods. The result clearly indicates that some of the oil samples exhibited unacceptable value when compared with physicochemical parameters recommended by the Codex Alimentations Commission of FAO/WHO and the specification of Ethiopian standards. The contents of nickel (Ni), copper (Cu) and iron (Fe) in seven samples were determined using ICP-OES and their concentrations were found in the range of 1.8-20.4, 45.8-82.2 and 136.04-445.0 mg/kg, respectively.

scholarly journals An Interaction of Anionic- and Cationic-Rich Mixed Surfactants in Aqueous Medium through Physicochemical Properties at Three Different Temperatures

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
K. M. Sachin ◽  
Sameer A. Karpe ◽  
Man Singh ◽  
Ajaya Bhattarai
Keyword(s):  
Physicochemical Properties ◽  
Hydrodynamic Radius ◽  
Sodium Dodecyl ◽  
Relative Viscosity ◽  
Solvent Interaction ◽  
Mixed Micellization ◽  
Surface Excess Concentration ◽  
Excess Concentration ◽  
Different Temperatures ◽  
Aqueous Binary Mixtures

The mixed micellization of aqueous binary mixtures of DTAB-rich and SDS-rich surfactants, comprising sodium dodecyl sulfate (SDS) and dodecyltrimethylammonium bromide (DTAB) is studied in aqueous solution by using the physicochemical properties (PCPs) at three different temperatures (T = 293.15, 298.15, and 303.15 K) and P=0.1  MPa. The DTAB concentration is varied from 0.0001 to 0.03 M/mol·L−1 in the ∼0.01 M/mol·L−1 SDS solution, while the concentration of SDS is varied from 0.001 to 0.015 M/mol·L−1 in the ∼0.005 M/mol·L−1 DTAB. The stable formulations have been obtained by employing the DTAB-rich and SDS-rich surfactants solutions in 3 : 1 ratio. Therefore, different phases and aggregated states formed in the ternary combinations of DTAB/SDS/H2O have been identified and described. The calculated PCPs have been utilized for determining the nature of the solute-solvent interaction (SLS0I). With increasing surfactants concentration, the polarisation of the solution also increases along with an increase in relative viscosity (ηr), viscous relaxation time (τ), and surface excess concentration (Γmax). However, the surface area of the molecule (Amin), hydrodynamic volume (Vh), and hydrodynamic radius (Rh) decrease along with an increase in surfactants concentration.

scholarly journals Physicochemical properties of silver catfish (Pangasius sp.) skin collagen as influenced by acetic acid concentration

Food Research ◽  
2019 ◽  
pp. 783-790
Author(s):  
N.H. Hadfi ◽  
N.M. Sarbon
Keyword(s):  
Acetic Acid ◽  
Physicochemical Properties ◽  
Acid Concentration ◽  
Relative Viscosity ◽  
Acetic Acid Concentration ◽  
Silver Catfish ◽  
Ph Values ◽  
Skin Collagen ◽  
Fish Collagen ◽  
Fibrous Morphology

The aim of this study was to investigate the physicochemical properties of silver catfish skin collagen as affected by acetic acid concentration (0.5M and 0.7M). Acid solubilised collagen (ASC) were isolated from the skin of silver catfish (Pangasius Sp.) and were compared with commercial collagen. The yields of extracted collagen using 0.5M and 0.7M acetic acid were 10.94±0.38% and 5.47±0.20%, respectively. The pH values for commercial collagen and extracted collagen for 0.5M and 0.7M acetic acid values were 6.52±0.04, 4.04±0.06 and 3.79±0.28, respectively. The functional group of collagen was successfully detected, along with a flaky and fibrous morphology structure. The relative viscosity for all samples decreased with an increase in temperature. Collagen extracted with 0.5M acetic acid is more efficient for use as a solvent for collagen extraction since it produces a higher yield and higher fibrous collagen thickness. This study found that collagen extracted from silver catfish (Pangasius sp.) had the potential to be used as alternative fish collagen in various fields.

scholarly journals Changes in Physicochemical Properties and Volatile Compounds of Roselle (Hibiscus sabdariffa L.) Calyx during Different Drying Methods

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6260
Author(s):  
Nurul Hanisah Juhari ◽  
Helle Jakobe Martens ◽  
Mikael Agerlin Petersen
Keyword(s):  
Moisture Content ◽  
Physicochemical Properties ◽  
Volatile Compounds ◽  
Freeze Drying ◽  
Cell Structure ◽  
Vacuum Drying ◽  
Drying Methods ◽  
Oven Drying ◽  
Sun Drying ◽  
Freeze Dried

Fresh roselle are high in moisture and deteriorate easily, which makes drying important for extending shelf-life and increasing availability. This study investigated the influence of different drying methods (oven-drying, freeze-drying, vacuum-drying, and sun-drying) on the quality of roselle calyx expressed as physicochemical properties (moisture content, water activity, soluble solids, color), volatile compounds, and microstructure. Oven-drying and freeze-drying reduced moisture content most while vacuum-drying and sun-drying were not as efficient. All drying methods except sun-drying resulted in water activities low enough to ensure safety and quality. Vacuum-drying had no impact on color of the dry calyx and only small impact on color of water extract of calyx. Drying reduced terpenes, aldehydes, and esters but increased furans. This is expected to reduce fruity, floral, spicy, and green odors and increase caramel-like aroma. Sun-drying produced more ketones, alcohols, and esters. Scanning electron microscopy revealed that freeze-drying preserved the cell structure better, and freeze-dried samples resembled fresh samples most compared to other drying techniques. The study concludes that freeze-drying should be considered as a suitable drying method, especially with respect to preservation of structure.

scholarly journals Research and implementation of innovative technologies for the use of composite polymer materials to protect the root systems of seedlings from desiccation and increase their establishment

2021 ◽  
Vol 36 ◽  
pp. 04006
Author(s):  
V.V. Kopytkov ◽  
Ch. Dorzhsuren ◽  
Yu.A. Tairbergenov
Keyword(s):  
Physicochemical Properties ◽  
Polymer Material ◽  
Sodium Salt ◽  
Active Substance ◽  
Relative Viscosity ◽  
Mechanical Damage ◽  
Root Systems ◽  
Polymer Materials ◽  
Composite Polymer ◽  
Composite Polymer Material

In the presented materials, the physicochemical properties of composite polymer materials for protecting the root systems of forest seedlings from desiccation are studied. The conducted studies on the production of composite polymer materials allowed to establish their optimal ratios: the sodium salt carboxymethyl cellulose from 4 active substance wt.%, as target additives contains potassium chloride from 6.0 to 9.0 wt.% and ammonium nitrate from 0.004 to 0.006 wt.%. This ratio of target additives corresponds to the optimal relative viscosity of the composite polymer material equal to 170-175 s. Treatment of the root systems of seedlings with a composite polymer material allows not only to prevent desiccation, increase their establishment on the planting area, but also to reduce mechanical damage during transportation and forest planting.

scholarly journals Effects of Different Processing Methods and Internal Components on Physicochemical Properties and Glycemic Index of Adzuki Bean Powder

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1685
Author(s):  
Feiyue Ren ◽  
Xiaoxue Yang ◽  
Lili Wang ◽  
Sumei Zhou
Keyword(s):  
Physicochemical Properties ◽  
Glycemic Index ◽  
Cell Structure ◽  
Starch Digestibility ◽  
Adzuki Bean ◽  
Physical Barrier ◽  
In Vitro Starch Digestibility ◽  
Essential Components ◽  
Estimated Glycemic Index

The estimated glycemic index (eGI) value of adzuki bean powder prepared by steamed cooking (SC), extruded cooking (EC) and roller cooking (RC) was studied comparatively. Results showed that RC had the highest eGI, with 80.1, and both EC and SC resulted in a lower eGI value of 70.0 and 49.7, respectively. Compared with the EC and RC methods, the SC method provided a more intact physical barrier for starch digestion, resulting in a less destroyed cell structure. As the essential components that form the cell wall, the study further investigated the effects of protein and fiber on physicochemical properties, in vitro starch digestibility and the eGI of adzuki bean powder processed with the SC method. Viscozyme and Protamax were used to obtain the deprotein and defiber samples. Results showed that the SC treatment with Viscozyme and Protamax, respectively, had significant effects on in vitro starch digestibility. The eGI of different samples were given as follows: steamed cooking adzuki bean powder (49.7) < deproteined adzuki bean powder (60.5) < defibered adzuki bean powder (83.1), which indicates that fiber may have a greater influence on the eGI than protein.

Basic cellular physiology

2017 ◽  
Author(s):  
Mark Harrison
Keyword(s):  
Fluid Dynamics ◽  
Emergency Medicine ◽  
Blood Flow ◽  
Action Potential ◽  
Cell Structure ◽  
Structure And Function ◽  
Muscle Physiology ◽  
Nervous Systems ◽  
Cellular Physiology ◽  
And Function

This chapter describes basic cellular physiology as it applies to Emergency Medicine, and in particular the Primary FRCEM examination. The chapter outlines the key details of homeostasis, compartments and fluid spaces, cell structure and function, vessel fluid dynamics, blood flow, neurological action potential, generated action potential, parasympathetic nervous systems, and muscle physiology. This chapter is laid out exactly following the RCEM syllabus, to allow easy reference and consolidation of learning.

Anomalous viscosity of human blood

1965 ◽  
Vol 208 (6) ◽  
pp. 1267-1269 ◽  
Author(s):  
George A. Mayer
Keyword(s):  
Flow Rate ◽  
Human Blood ◽  
Relative Viscosity ◽  
Capillary Viscometer ◽  
Distilled Water ◽  
Anomalous Viscosity ◽  
Blood Relative

The viscosity of human blood relative to distilled water observed in a capillary viscometer decreases with the length (in the range of 1.65– 10.5 cm) and increases with the reduction of the radius (in the range of .0106–.0217 cm) of the capillaries. No such changes are present when the flow rate of oils instead of water is used for the calculation of relative viscosity. Since homogeneous Newtonian oils exhibit a viscosity pattern similar to that of human blood, the existence of an "anomalous viscosity" of human blood described by Fahraeus and Lindqvist was not confirmed.

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