Tailoring flexibility and dispersity of thermoplastic starch gel by controlling intermolecular structure for improving folding endurance of polylactide

2021 ◽  
Vol 159 ◽  
pp. 110731
Author(s):  
Wanjie Si ◽  
Shuidong Zhang ◽  
Yan He ◽  
Yu-Kun Chen
1969 ◽  
Vol 21 (03) ◽  
pp. 428-440 ◽  
Author(s):  
N. O Solum ◽  
S Łopaciuk

Summary1. Some properties of purified bovine platelet fibrinogen have been described and the data compared to those obtained by parallel analysis of purified bovine plasma fibrinogen.2. A close similarity was found between platelet and plasma fibrinogen as to sedimentation coefficients, electrophoretic mobilities in starch gel and polyacrylamide disc electrophoresis, light absorption spectra in the range 240 mμ to 330 mμ, ability to form immunoprecipitate with a rabbit antiserum against bovine plasma fibrinogen, total amino acid composition and in N-terminal amino acids.Differences between the fibrinogens were found as to intrinsic viscosity, carbohydrate content and behaviour upon clotting by thrombin. Intrinsic viscosity in 0.3 M NaCl at 25° was 0.48 dl/g for platelet fibrinogen as compared to 0.26 dl/g for plasma fibrinogen. The carbohydrate content of platelet fibrinogen was 0.56 ± 0.10% 1.56±0.10% and 1.37±0.09% for sialic acid (calculated as N-glycolyl neuraminic acid), hexose (galactose/mannose 1:2) and hexosamine (glucosamine), respectively. These values were 6, 54 and 26% higher than those found for plasma fibrinogen. The difference in clotting behaviour indicated a slower polymerization rate of the fibrin monomers formed from platelet fibrinogen than of those formed from plasma fibrinogen.


1969 ◽  
Vol 21 (03) ◽  
pp. 419-427 ◽  
Author(s):  
N. O Solum ◽  
S Łopaciuk

Summary1. Platelet fibrinogen has been purified from washed bovine platelets. The procedure was based on the methods for purification of plasma fibrinogen by fractionated precipitations and extractions with ethanol and glycine below 0°, and precipitation of proteins by dimethylformamide at 0°.2. The platelet extract obtained by freezing and thawing of the cells, freed from insoluble material by centrifugation at 23,000 x g for 30 min, contained 0.22 ±0.003mg fibrinogen per 109 platelets. Total protein of this fraction was 0.77 ±0.08 mg per 109 platelets whereas that of the insoluble fraction was 0.79 ±0.09 mg per 109 platelets.3. The most purified platelet fibrinogen fraction contained 91-98% of the protein in a thrombin-clottable state. The yield was approx. 20%. It showed homogeneity in analytical ultracentrifugation, in immunoelectrophoresis using an antiserum produced by immunization of rabbits against platelet extract, and in starch gel electrophoresis using a discontinuous system of Tris HCl and borate buffers offering a high resolution power towards the platelet proteins. Polyacrylamide disc electrophoresis revealed two to three faint lines behind the main fibrinogen line. At least one such line was also observed with purified plasma fibrinogen.


1966 ◽  
Vol 16 (03/04) ◽  
pp. 526-540 ◽  
Author(s):  
E. A Beck ◽  
D. P Jackson

SummaryThe effects of trypsin and plasmin on the functional and physicochemical properties of purified human fibrinogen were observed at various stages of proteolysis. Concentrations of plasmin and trypsin that produced fibrinogenolysis at comparable rates as measured in a pH stat produced, at similar rates, loss of precipitability of fibrinogen by heat and ammonium sulphate and alterations in electrophoretic mobility on starch gel. Trypsin produced a more rapid loss of clottability of fibrinogen and a more rapid appearance of inhibitors of the thrombin-fibrinogen clotting system than did plasmin. Consistent differences were noted between the effects of trypsin and plasmin on the immunoelectrophoretic properties of fibrinogen during the early stages of proteolysis.These results are consistent with the hypothesis that trypsin initially reacts with the same peptide bonds of fibrinogen that are split by thrombin, but these same bonds do not appear to be split initially by plasmin. Measurement of the various functional and physico-chemical changes produced by the action of trypsin and plasmin on fibrinogen can be used to recognize various stages of proteolysis.


1964 ◽  
Vol 12 (01) ◽  
pp. 126-136 ◽  
Author(s):  
Karl H. Slotta ◽  
J. D Gonzalez

SummaryWhen urea or ε-amino caproic acid were used as solublizing agents for plasminogen in electrophoretic experiments, only one broad band of the proenzyme was obtained on acetate cellulose, in starch block, and in acrylamide gel. In starch gel electrophoresis, however, both forms of plasminogen – the native or euglobulin and Kline’s or Pseudoglobulin plasminogen – separated into six bands. These migrated toward the cathode at room temperature in borate or veronal buffer in the alkaline range and showed full activity in fibrinagar-streptokinase plates.


2020 ◽  
Vol 14 (1) ◽  
pp. 289-301
Author(s):  
Daniel Oni ◽  
John Mwero ◽  
Charles Kabubo

Background: Concrete is a common material used in the construction of marine structures, such as bridges, water treatment plants, jetties, etc. The use of concrete in these environment exposes it to attack from chemicals like sulphates, chlorides and alkaline, thereby causing it to deteriorate, and unable to perform satisfactorily within its service life. Hence, the need to investigate the durability properties of concrete has become necessary especially when admixtures are used to modify some of its properties. Objective: This research work investigates the effect of Cassava Starch (CS) on the durability characteristics of concrete. Methods: The durability properties investigated in this work are water absorption, sorptivity, resistance to sulphates, sodium hydroxides and chloride penetration. The specimens were prepared by adding CS by weight of cement at 0.4, 0.8, 1.2, 1.6 and 2.0% respectively. The concrete specimens were cured for 28 days, tested for compressive strength before ponding in ionic solutions of sodium hydroxide, sulphuric acid and sodium chloride. Six (6) concrete mixes were prepared, five of which were used to evaluate the effect of CS on the durability characteristics of concrete. Results: The slump values reduced with the increasing dosage of CS due to the viscous nature of the CS paste. Generally, the addition of CS in concrete tends to improve the resistance of concrete to sulphate and chloride attack due to the ability of the muddy-like starch gel to block the pore spaces of hardened concrete, hence, reduces the rate at which water and other aggressive chemicals penetrate the concrete. In addition, the retarding ability of CS impedes the formation of mono-sulphate aluminates during cement hydration, thereby making the concrete less susceptible to sulphate attack. Conclusion: The addition of CS to concrete by weight of cement generally improved the durability characteristics of concrete, while the relative performances of the concrete mixes showed that CS 2.0 gave a better resistance to chloride penetration and sulphate attack.


Author(s):  
SHUBHAM BIYANI ◽  
SARANG MALGIRWAR ◽  
RAJESHWAR KSHIRSAGAR ◽  
SAGAR KOTHAWADE

Objective: The intension of the present study includes fabrication and optimization of mouth dissolving film loaded with Chlorothalidone by solvent evaporation techniques using two components and their three levels as multilevel Categoric design. Methods: Major problem associated with the development of film loaded with BCS class II drug is to increase its solubility. Here the Chlorothalidone solubility achieved by co-solvents, such as methanol. After dissolving the drug in co-solvent, this drug solution is poured into an aqueous dispersion of Hydroxypropyl Methylcellulose E5 (HPMC E5) and Polyethylene glycol 400 (PEG 400). The two independent variables selected are factor A (concentration of HPMC E5) and factor B (concentration of PEG 400) was selected on the basis of preliminary trials. The percentage drug release (R1), Disintegration time in sec (R2) and folding endurance (R3) were selected as dependent variables. Here HPMC E5 used as a film former, PEG 400 as plasticizer, mannitol as bulking agent, Sodium starch glycolate as a disintegrating agent, tween 80 as the surfactant, tartaric acid as saliva stimulating agent, sodium saccharin as a sweetener and orange flavour etc. These fabricated films were evaluated for physicochemical properties, disintegration time and In vitro drug release study. Results: The formulation F6 has more favorable responses as per multilevel categoric design is % drug release about 98.95 %, average disintegration time about 24.33 second and folding endurance is 117. Thus formulation F6 was preferred as an optimized formulation. Conclusion: The present formulation delivers medicament accurately with good therapeutic efficiency by oral administration, this mouth dissolving films having a rapid onset of action than conventional tablet formulations.


Genetics ◽  
1982 ◽  
Vol 102 (3) ◽  
pp. 539-556
Author(s):  
Don C Morizot ◽  
Michael J Siciliano

ABSTRACT The products of 49 protein-coding loci were examined by starch gel electrophoresis for populational variation in six species of Xiphophorus fishes and/or segregation in intra- and interspecific backcross and intercross hybrids. Electrophoretic variation was observed for 29 of the 35 locus products in a survey of 42 population samples. The highest frequency of polymorphic loci observed in noninbred populations was 0.143. After ten or more generations of inbreeding, all loci studied were monomorphic. Inbred strains generally exhibited the commonest electrophoretic alleles of the population from which they were derived. An assessment of genetic distances among Xiphophorus populations reflected classical systematic relationships and suggested incipient subspeciation between X. maculatus from different drainages as well as several species groups. Thirty-three loci were analyzed with respect to segregation in hybrids. The goodness of fit of segregations to Mendelian expectations at all loci analyzed (except loci in linkage group I) is interpreted as evidence for high genetic compatibility of the genomes of Xiphophorus species. It is anticipated that these data will result in a rapid expansion of the assignment of protein-coding loci to linkage groups in these lower vertebrate species.


Genetics ◽  
1973 ◽  
Vol 74 (4) ◽  
pp. 595-603
Author(s):  
D Borden ◽  
E T Miller ◽  
D L Nanney ◽  
G S Whitt

ABSTRACT The isozymic patterns of tyrosine aminotransferase, NADP malate dehydrogenase, NADP isocitrate dehydrogenase, and tetrazolium oxidase were examined by starch-gel electrophoresis in Tetrahymena pyriformis, syngen 1. The genetics of the alleles controlling these enzymes was studied through a breeding program. Each enzyme locus was shown to assort vegetatively, as do other loci in this organism. A detailed analysis of the assortment process for the tyrosine aminotransferase locus indicated that the rate of stabilization of heterozygotes into pure types was essentially identical to previously-reported rates for other loci.


Author(s):  
Tali H. Horst ◽  
Richard D. Smith ◽  
Antje Potthast ◽  
Martin A. Hubbe

AbstractThree copies of a book that had been optionally deacidified using two different procedures in 1967, and then subjected to accelerated aging, were tested again after 52 years of natural aging. Matched copies of the book Cooking the Greek Way, which had been printed in Czechoslovakia on acidic paper, were evaluated. Nonaqueous treatment of two of the copies with magnesium methoxide dissolved in chlorofluorocarbon solvent had been found in 1967 to have decreased the susceptibility to embrittlement, as evidenced by the results of the accelerated aging, followed by folding endurance tests. Retesting of the same books in 2019, after 52 years of room temperature storage, showed that the deacidification treatments had achieved the following benefits in comparison to the untreated book: (a) higher brightness; (b) higher folding endurance; (c) tensile breaking length higher in the cross-direction of the paper; (d) substantial alkaline reserve content, (e) an alkaline surface pH in the range 7.1–7.4, and (f) higher molecular mass of the cellulose. Remarkably, some of the folding endurance results matched those of unaged samples evaluated in 1967. Scanning electron micrographs showed no differences between the treated and untreated books.


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