Evaluation of the efficiency of solvent-precipitant systems for the fractionation of polyvinyl chlorides on a molecular weight basis

1955 ◽  
Vol 20 (4) ◽  
pp. 940-947 ◽  
Author(s):  
Z. Menčík
Keyword(s):  
Molecular Weight ◽  
Weight Basis

Neutralisation of Heparan Sulphate and Low Molecular Weight Heparin by Protamine

1985 ◽  
Vol 53 (01) ◽  
pp. 086-089 ◽  
Author(s):  
A R Hubbard ◽  
C A Jennings
Keyword(s):  
Molecular Weight ◽  
Plasma Proteins ◽  
Low Molecular Weight Heparin ◽  
Heparan Sulphate ◽  
Activated Partial Thromboplastin Time ◽  
Weight Basis ◽  
Low Molecular Weight ◽  
Protamine Sulphate ◽  
At Iii ◽  
Reference Preparation

SummaryThe neutralisation by protamine sulphate (PS) of heparan sulphate (HS), a low molecular weight heparin (LMWH), and a reference preparation of unfractionated heparin (UH), was studied by activated partial thromboplastin time (APTT) and anti-Xa clotting assays. UH was most easily neutralised in the APTT assay by PS (on a weight for weight basis), followed by LMWH and HS. The neutralisation of APTT activity by PS closely followed the loss of activity in the anti-Xa clotting assay, when plasma was used as the source of At III. When the anti-Xa clotting assay was carried out using purified At III in place of plasma, HS and LMWH were neutralised by much lower amounts of PS and resembled UH neutralisation more closely. Resistance of HS anti-Xa activity to PS neutralisation decreased with increasing plasma dilution. The presence of bovine albumin with purified At III concentrate increased the resistance of HS to PS neutralisation. It is concluded that PS binding to UH, HS and LMWH is probably related more to their degree of sulphation than molecular weight and that non-specific interactions between PS and plasma proteins inhibit the binding of PS to HS and LMWH.

scholarly journals THE MOLECULAR WEIGHT OF RHODOPSIN AND THE NATURE OF THE RHODOPSIN-DIGITONIN COMPLEX

1954 ◽  
Vol 37 (3) ◽  
pp. 381-399 ◽  
Author(s):  
Ruth Hubbard
Keyword(s):  
Molecular Weight ◽  
Single Molecule ◽  
Extinction Coefficient ◽  
Dry Weight ◽  
Weight Basis ◽  
Sedimentation Behavior ◽  
A Value ◽  
Wet Weight ◽  
Single Boundary ◽  
Stoichiometric Complex

The sedimentation behavior of aqueous solutions of digitonin and of cattle rhodopsin in digitonin has been examined in the ultracentrifuge. In confirmation of earlier work, digitonin was found to sediment as a micelle (D-1) with an s20 of about 6.35 Svedberg units, and containing at least 60 molecules. The rhodopsin solutions sediment as a stoichiometric complex of rhodopsin with digitonin (RD-1) with an s20 of about 9.77 Svedberg units. The s20 of the RD-1 micelle is constant between pH 6.3 and 9.6, and in the presence of excess digitonin. RD-1 travels as a single boundary also in the electrophoresis apparatus at pH 8.5, and on filter paper at pH 8.0. The molecular weight of the RD-1 micelle lies between 260,000 and 290,000. Of this, only about 40,000 gm. are due to rhodopsin; the rest is digitonin (180 to 200 moles). Comparison of the relative concentrations of RD-1 and retinene in solutions of rhodopsin-digitonin shows that RD-1 contains only one retinene equivalent. It can therefore contain only one molecule of rhodopsin with a molecular weight of about 40,000. Cattle rhodopsin therefore contains only one chromophore consisting of a single molecule of retinene. It is likely that frog rhodopsin has a similar molecular weight and also contains only one chromophore per molecule. The molar extinction coefficient of rhodopsin is therefore identical with the extinction coefficient per mole of retinene (40,600 cm.2 per mole) and the E(1 per cent, 1 cm., 500 mµ) has a value of about 10. Rhodopsin constitutes about 14 per cent of the dry weight, and 3.7 per cent of the wet weight of cattle outer limbs. This corresponds to about 4.2 x 106 molecules of rhodopsin per outer limb. The rhodopsin content of frog outer limbs is considerably higher: about 35 per cent of the dry weight, and 10 per cent of the wet weight, corresponding to about 2.1 x 109 molecules per outer limb. Thus the frog outer limb contains about five hundred times as much rhodopsin as the cattle outer limb. But the relative volumes of these structures are such that the ratio of concentrations is only about 2.5 to 1 on a weight basis. Rhodopsin accounts for at least one-fifth of the total protein of the cattle outer limb; for the frog, this value must be higher. The extinction (K500) along its axis is about 0.037 cm.2 for the cattle outer limb, and about 0.50 cm.2 for the frog outer limb.

Bis(Triethoxysilylethyltolylene)-Polysulfide, a Scorch-Resistant Silane Coupling Agent for Mineral-Filled Elastomers

1983 ◽  
Vol 56 (1) ◽  
pp. 94-104 ◽  
Author(s):  
R. J. Pickwell
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Coupling Agent ◽  
Calcium Silicate ◽  
Silane Coupling Agent ◽  
Weight Basis ◽  
Filled Elastomers ◽  
Silane Coupling

Abstract Bis(triethoxysilylethyltolylene)polysulfide offers greater scorch safety and reduced odor compared to mercaptosilanes, though its high molecular weight may require up to three times the mercaptosilane loading on a weight basis. This is highly dependent on the rubber formulation. The polysulfidedisilane can be made into stable dispersions on calcium silicate at concentrations up to 70 percent. Order-of-addition recommendations for the polysulfidedisilane are the same as those for mercaptosilanes. Different mix procedures should be checked for each formulation to ensure maximum silane effectiveness.

scholarly journals Extraction and Characterization of Sugarcane Peel Wax

ISRN Agronomy ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Mangesh B. Inarkar ◽  
S. S. Lele
Keyword(s):  
Fatty Acids ◽  
Molecular Weight ◽  
Gas Chromatography ◽  
Fourier Transform ◽  
Dry Weight ◽  
Weight Basis ◽  
Ft Ir ◽  
Gas Chromatography Mass Spectroscopy ◽  
Layer Chromatography

Sugarcane peel is an agrowaste product and contains considerable amount of wax. This has a good technoeconomic potential. In view of this, the present study aims at extraction and characterization of wax from sugarcane peel. The yield of crude wax was 0.95% on dry weight basis. During Fourier transform-infrared spectroscopy (FT-IR) prominent peaks obtained at 2921.73 and 2851.64 (–CH), 1463.44 (–CH2), 1376.96 (–CH3), 1108.4 and 1170.16 (–C–O) 3395.60 (–OH), 1710.25 (–CHO), and 1736.63 (–COOH) indicate presence of alkanes, ketones, alcohols, aldehydes, and carboxylic acids, respectively. Alcohol and hydrocarbon fractions were also found by thin layer chromatography (TLC). Melting point of crude wax was observed to be 62.1°C. Molecular weight of wax was estimated to be 1706 Dalton. Composition of crude wax found using gas chromatography-mass spectroscopy (GC-MS) was alkanes (28.83%), ester (66.26%), fatty acids (4.58%), aldehyde (0.11%), and alcohol (0.22%).

scholarly journals Proteine als Schutzstoffe gegenüber dem Gefriertod der Zelle

1970 ◽  
Vol 25 (8) ◽  
pp. 834-842 ◽  
Author(s):  
U. Heber ◽  
M. Kempfle
Keyword(s):  
Molecular Weight ◽  
Frost Tolerance ◽  
Thylakoid Membranes ◽  
Weight Basis ◽  
Unit Weight ◽  
Low Molecular Weight ◽  
Complete Protection ◽  
Highly Active ◽  
Heat Stable ◽  
Better Than

Two protein factors from hardy leaves were highly active in preventing the inactivation of photophosphorylation of washed thylakoid membranes which takes place during freezing of thylakoids in the absence of protective compounds. Non-hardy leaves did not yield protective protein material. On a unit weight basis, protection by the protein factors was 10 to 100 times better than protection by compounds of low molecular weight such as sucrose, glycerol or dimethylsulfoxide. Very low amounts of the protein factors, which alone were scarcely protective, considerably reduced the concentration of sucrose required for the complete protection of thylakoids during freezing. The protein factors were heat-stable and had a molecular weight between 10 000 and 20 000 daltons. It is assumed that they contribute to and are in part responsible for the frost tolerance of hardy plant material.

scholarly journals On the venom of the lesser weeverfish, Trachinus vipera

1962 ◽  
Vol 42 (2) ◽  
pp. 155-162 ◽  
Author(s):  
D. B. Carlisle
Keyword(s):  
Molecular Weight ◽  
Toxic Effect ◽  
Dry Weight ◽  
Weight Basis ◽  
Low Molecular Weight ◽  
Neurotoxic Effect ◽  
Local Pain ◽  
Dorsal Fin ◽  
Single Complex

SUMMARYA method is described for obtaining the venom from the dorsal fin of the lesser weever without harming the fish. It is suggested that the amount of venom normally injected into the wound by the weever when it stings is O-5-O-2 mg dry weight of venom. Some 60% of the dry weight of the venom appears to consist of toxic muco-substances, which have a neurotoxic effect, but are without toxic effect on the blood. In extracts this fraction may be separated into two albumins and an amino polysaccharide, though in the native venom these are probably associated into a single complex mucosubstance. When injected subcutaneously this fraction of the venom produces no local pain. The venom also contains about 1-20 jug/mg (dry-weight basis) of 5-hydroxytryptamine which appears to be the origin of the pain of the sting, together with some undetermined histamine releaser (not an indole) of low molecular weight. It is suggested that the chief role of the 5-hydroxytryptamine in the venom is to produce pain around the area of the inflicted wound.

COMPOSITION OF TRACHEOBRONCHIAL SECRETIONS IN CYSTIC FIBROSIS OF THE PANCREAS AND BRONCHIECTASIS

PEDIATRICS ◽  
1959 ◽  
Vol 24 (5) ◽  
pp. 739-745
Author(s):  
Warren S. Chernick ◽  
Giulio J. Barbero
Keyword(s):  
Cystic Fibrosis ◽  
Molecular Weight ◽  
Ionic Composition ◽  
Calcium Content ◽  
Dry Weight ◽  
Ionic Concentration ◽  
Weight Basis ◽  
Desoxyribonucleic Acid ◽  
Inorganic Constituents ◽  
Sodium And Potassium

Tracheobronchial secretions obtained by bronchoscopic aspiration from patients with cystic fibrosis and patients with chronic bronchiectasis were analyzed for the major organic and inorganic constituents. The tracheobronchial secretions from patients with cystic fibrosis contained, on a weight basis, at least twice the quantity of organic material found in bronchiectatic secretions. Analysis of the secretions for nitrogen, carbohydrate, hexosamine and lipids indicated that, on a dry weight basis, similar quantities of these organic constituents are found in the two types of secretions. The only organic component which was found to be consistently different was desoxyribonucleic acid; a higher content was found in cystic fibrosis secretion. Analysis of the inorganic constituents revealed a higher content of sodium and potassium in the bronchiectatic secretion when calculated both on the basis of wet and dry weight, whereas phosphorus was found to be higher in the cystic fibrosis secretion. The calcium content in the total cystic fibrosis secretion was found to be twice that in the bronchiectatic material; however, when calculated on the basis of dry weight, both types of secretion contained similar amounts of calcium. The influence of ionic composition of the surrounding media on high molecular weight polymers is discussed and the postulation made that an alteration in the ionic concentration may be responsible for the peculiar characteristics observed in the tracheobronchial secretions of patients with cystic fibrosis.

Evaluation of the dark field method for large association of spread DNA

1978 ◽  
Vol 36 (2) ◽  
pp. 190-191
Author(s):  
Douglas C. Barker
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Mitochondrial Dna ◽  
Extraction Method ◽  
Field Method ◽  
Dark Field ◽  
Kinetoplast Dna ◽  
Field Electron ◽  
Field Electron Microscopy ◽  
Dark Field Electron

A number of satisfactory methods are available for the electron microscopy of nicleic acids. These methods concentrated on fragments of nuclear, viral and mitochondrial DNA less than 50 megadaltons, on denaturation and heteroduplex mapping (Davies et al 1971) or on the interaction between proteins and DNA (Brack and Delain 1975). Less attention has been paid to the experimental criteria necessary for spreading and visualisation by dark field electron microscopy of large intact issociations of DNA. This communication will report on those criteria in relation to the ultrastructure of the (approx. 1 x 10-14g) DNA component of the kinetoplast from Trypanosomes. An extraction method has been developed to eliminate native endonucleases and nuclear contamination and to isolate the kinetoplast DNA (KDNA) as a compact network of high molecular weight. In collaboration with Dr. Ch. Brack (Basel [nstitute of Immunology), we studied the conditions necessary to prepare this KDNA Tor dark field electron microscopy using the microdrop spreading technique.

Introduction

1978 ◽  
Vol 36 (3) ◽  
pp. 543-544
Author(s):  
W. Bernard
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Nucleic Acid ◽  
Gene Mapping ◽  
Molecular Genetics ◽  
Cell Biology ◽  
Gene Activity ◽  
Close Connection ◽  
Basic Information ◽  
Simple Systems

In comparison to many other fields of ultrastructural research in Cell Biology, the successful exploration of genes and gene activity with the electron microscope in higher organisms is a late conquest. Nucleic acid molecules of Prokaryotes could be successfully visualized already since the early sixties, thanks to the Kleinschmidt spreading technique - and much basic information was obtained concerning the shape, length, molecular weight of viral, mitochondrial and chloroplast nucleic acid. Later, additonal methods revealed denaturation profiles, distinction between single and double strandedness and the use of heteroduplexes-led to gene mapping of relatively simple systems carried out in close connection with other methods of molecular genetics.

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