scholarly journals ON THE NATURE OF FORCES OPERATING IN BLOOD CLOTTING

1945 ◽  
Vol 29 (2) ◽  
pp. 113-122 ◽  
Author(s):  
W. F. H. M. Mommaerts
Keyword(s):  
Hydrogen Bonds ◽  
Isoelectric Point ◽  
Blood Clotting ◽  
Electrostatic Attraction ◽  
Primary Reaction ◽  
Ph Values ◽  
Positively Charged

It is found that clotting of fibrinogen by thrombin does not occur on the acid side of the isoelectric point of the fibrinogen. At such pH values, however, a primary reaction between thrombin and fibrinogen takes place, leading to the formation of profibrin, a compound of thrombin and fibrinogen. At pH values at which clotting is possible, fibrinogen is negatively, thrombin positively charged, whereas profibrin has a pattern of positive and negative charges. The primary reaction, the formation of profibrin by combination of thrombin and fibrinogen, is inhibited by urea but not by neutral salts. The combination of thrombin with fibrinogen most probably takes place by hydrogen bonds. The second reaction, the polymerisation of profibrin to fibrin, is inhibited by neutral salts in the same way as complex or autocomplex coacervates. It is caused therefore by electrostatic attraction between the positive and the negative charges of the profibrin.

scholarly journals EFFECT OF ELECTROLYTES ON ELECTROSURFACE PROPERTIES OF MICROCRYSTALLINE CELLU-LOSE PARTICLES

2021 ◽  
pp. 55-60
Author(s):  
Aleksandr Valentinovich Lorentsson ◽  
Nadezhda Leonidovna Koroleva ◽  
Yuriy Mitrofanovich Chernoberezhskii
Keyword(s):  
Isoelectric Point ◽  
Specific Adsorption ◽  
Point Of Zero Charge ◽  
Ph Values ◽  
Zero Charge ◽  
Anions And Cations ◽  
Acidic Region ◽  
Charge Point ◽  
Positively Charged ◽  
Specific Adsorption Of Ions

The electrical surface properties (specific surface charge of particles - σ0, point of zero charge – pHPZC, electrokinetic potential - ζ and position of isoelectric point - pHIEP) of dispersions of microcrystalline cellulose (MCC) in aqueous solutions of H2SO4, NaOH, Na2SO4 and TiOSO4 were investigated. Significant effects of specific adsorption of anions and cations on pHPZC and pHIEP have been demonstrated. The isoelectric point of the MCC particles in the H2SO4 solution is at pH 2.0, while the zero charge point in 5·10-4 M solution Na2SO4 at pH 5.6. An explanation of the observed effects is given. Possible schemes of the structure of the electrical double layer at different pH values, taking into account specific adsorption of ions in the Stern layer, are given. The introduction of TiOSO4 (10-5 mol/dm3) shifts the position of IEP to a less acidic region (pHIEP 4.5) due to the specific adsorption of positively charged TiOSO4 hydrolysis products particles.

scholarly journals Electrothermal supercharging of proteins in native MS: effects of protein isoelectric point, buffer, and nanoESI-emitter tip size

The Analyst ◽  
2016 ◽  
Vol 141 (19) ◽  
pp. 5598-5606 ◽  
Author(s):  
Daniel N. Mortensen ◽  
Evan R. Williams
Keyword(s):  
Isoelectric Point ◽  
Native Ms ◽  
Positively Charged

The extent of charging resulting from electrothermal supercharging increases with decreasing tip size for positively charged proteins.

Secondary Bonding Interactions in Some Dichloroanilinium Chlorides

2002 ◽  
Vol 57 (1) ◽  
pp. 73-82 ◽  
Author(s):  
Lilian Gray ◽  
Peter G. Jones
Keyword(s):  
Hydrogen Bonds ◽  
Layer Structure ◽  
The Other ◽  
Hydrogen Atoms ◽  
Ribbon Structure ◽  
Bonding Systems ◽  
Ribbon Structures ◽  
Chloride Hydrate ◽  
Positively Charged ◽  
Secondary Bonding

Of the six structures presented here, five involve clearly defined hydrophilic layers built up from classical hydrogen bonding systems. Of three solvent-free structures, 2,4- and 3,5-dichloroanilinium chlorides both form ribbon structures involving annelated R24 (8) rings with NH2 donors (two hydrogen atoms from the positively charged NH3 groups) and chloride acceptors. The ribbons are linked by weaker interactions to form layers. 2,5-Dichloroanilinium chloride forms a layer structure directly, with rings R36 (12) exactly analogous to those previously observed in 2-chloroanilinium chloride. 2,6-Dichloroanilinium chloride methanol solvate forms a different type of ribbon structure, with alternating R24 (8) and R46 12) rings; the latter involve two chlorides, two NH2 groups and two methanols. These ribbons too are linked to form layers. 2,3-Dichloroanilinium chloride hydrate forms layers with two types of ring R35 (10); one involves two NH2, two chlorides and the OH part of a water, whereas in the other, an NH2 is replaced by OH2. In all these structures the aromatic groups project approximately perpendicular to the layers to form hydrophobic regions; for all except 3,5-dichloroanilinium chloride, neighbouring layers are linked by weaker interactions such as C-H···Cl hydrogen bonds or Cl···Cl contacts. The final structure, 3,5-dichloroanilinium chloride 1/4-hydrate, is completely different; it involves two types of columns, one built up from quadrilaterals of Cl···Cl contacts between cations and the other consisting of “nanotubes ’ of NH3 groups and chloride anions linked by two- and three-centre hydrogen bonds. The columns are in turn linked by cation-anion Cl···Cl interactions.

Assembly of Nanoparticles from Bioactive Peptides and Chitosan

2011 ◽  
Vol 1312 ◽  
Author(s):  
B. Hu ◽  
Q. R. Huang ◽  
X. X. Zeng
Keyword(s):  
Electrophoretic Mobility ◽  
Bioactive Peptides ◽  
Molecular Chain ◽  
Mass Ratio ◽  
Ph Values ◽  
Transmission Electron ◽  
Low Salt ◽  
Liquid Chromatography Tandem Mass ◽  
Positively Charged ◽  
Critical Ph

ABSTRACTAssembly of nanoparticles from bioactive peptides, caseinophosphopeptides (CPPs) and chitosan (CS) at physiological conditions and various CS/CPPs mass ratios have been systematically studied using a combination of turbidimetric titration, dynamic light scattering (DLS), electrophoretic mobility (zeta-potential) and transmission electron microscopy (TEM). Peptides, incorporated with CS forming nanoparticles, have already been prepared and identified using liquid chromatography-tandem mass spectrometry (LC-MS-MS). They are characteristic with different amount of clusters of phosphorylated seryl residues. At low salt concentration, an increase of CS/CPP mass ratio shifted the critical pHϕ1, which designated the formation of CS/CPP nanocomplexes, as well as pHmax, representing the neutralization of positive and negative charge to higher pH values. The peptide-polymer binding mechanism was analyzed according to the results of DLS, electrophoretic mobility, and TEM. First, negatively charged CPPs absorbed to positively charged CS molecular chain to form intrapolymer nanocomplexes saturated with CPPs (CPPNP). Then, the negatively charged CPPNP was bridged by added positively charged CS. Finally, novel nano-scaled spherical brushes were formed as additional CS molecule absorbed back to and bound the CPPNP. Phosphorylated groups in the CPPs might be the dominant sites for interaction with –NH3+ on the CS molecular chain.

scholarly journals Stability of Positively Charged Nanoemulsion Formulation Containing Steroidal Drug for Effective Transdermal Application

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Stephanie Da Costa ◽  
Mahiran Basri ◽  
Norashikin Shamsudin ◽  
Hamidon Basri
Keyword(s):  
Particle Size ◽  
Delivery System ◽  
Correlation Spectroscopy ◽  
Good Stability ◽  
Ph Values ◽  
Transdermal Application ◽  
Oil In Water ◽  
Steroid Drugs ◽  
Positively Charged ◽  
Dermal Application

This paper emphasizes the formation of a positively charged nanoemulsion system for steroid drugs (hydrocortisone). It is believed that positively charged nanoemulsion provides more effective penetration of the skin. Therefore in our study we focused on the incorporation of phytosphingosine which serves as a positively charged cosurfactant in the nanoemulsion system. Negatively charged nanoemulsions were formulated mainly for comparison. Freshly prepared formulations were formed with particle size less than 300 nm and showed good stability over time. The oil-in-water nanoemulsion also showed good viscosity, conductivity, and pH values. From TEM micrograph, particle size showed consistent results with the measurement using photon correlation spectroscopy. It was concluded that both positively and negatively charged nanoemulsions showed good stability and have great potential in transdermal delivery system. Though, further investigation of the drug release and drug penetration of both positively and negatively charged nanoemulsions will be studied to further prove the efficacy of nanoemulsion with hydrocortisone as a delivery system for dermal application.

scholarly journals ON THE NATURE OF FORCES OPERATING IN BLOOD CLOTTING

1945 ◽  
Vol 29 (2) ◽  
pp. 103-112 ◽  
Author(s):  
W. F. H. M. Mommaerts
Keyword(s):  
Ionic Radius ◽  
Blood Clotting ◽  
Electrostatic Attraction ◽  
Inhibiting Effect

The results of the study of the inhibiting effect of neutral salts upon the clotting tendency of fibrinogen by thrombin may be summarised as follows: Salts like NaCl and KCl inhibit only weakly. Salts of the same cation (K•) with monovalent anions of different ionic radius are the more active the larger the anion (Cl',Br',I'). Salts of the same cation with anions of different valency are the more active the higher the charge of the anion (1–1 <1–2 <1–3 <1–4). Salts with the same anion with cations of different valency show stronger inhibition in the case of cations of higher charge (K•,Na• < Mg••, Ca••, Sr••, Ba••). Salts with the same anion and cations of the same charge, but of different radius, are the more active the larger the cation (but with an inversion between Mg•• and Ca•• in the series of the alkali earths, which is not infrequent in biocolloids). These results show that the clotting of fibrinogen with thrombin is, at least partly, caused by a coacervation process, due to electrostatic attraction between positive and negative groups. Its nature and localisation will be dealt with in the next paper of this series.

scholarly journals 4-(2-Methoxyphenyl)piperazin-1-ium 6-chloro-5-isopropyl-2,4-dioxopyrimidin-1-ide

2014 ◽  
Vol 70 (3) ◽  
pp. o245-o246 ◽  
Author(s):  
Fatmah A. M. Al-Omary ◽  
Hazem A. Ghabbour ◽  
Ali A. El-Emam ◽  
C. S. Chidan Kumar ◽  
Hoong-Kun Fun
Keyword(s):  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Phenyl Ring ◽  
Chair Conformation ◽  
Two Dimensional ◽  
Piperazine Ring ◽  
Π Interactions ◽  
Crystal Stability ◽  
Dimensional Network ◽  
Positively Charged

In the cation of the title salt, C11H17N2O+·C7H8ClN2O2−, the piperazine ring adopts a distorted chair conformation and contains a positively charged N atom with quaternary character. Its mean plane makes a dihedral angle of 42.36 (8)° with the phenyl ring of its 2-methoxyphenyl substituent. The 2,4-dioxopyrimidin-1-ide anion is generated by deprotonation of the N atom at the 1-position of the pyrimidinedione ring. Intramolecular C—H...O hydrogen bonds generateS(6) ring motifs in both the cation and the anion. In the crystal, N—H...O, N—H...N and C—H...O hydrogen bonds are also observed, resulting in a two-dimensional network parallel to theabplane. The crystal stability is further consolidated by weak C—H...π interactions.

scholarly journals Electrokinetic properties of chemically modified jute fabrics

2020 ◽  
pp. 69-69
Author(s):  
Aleksandra Ivanovska ◽  
Mirjana Kostic
Keyword(s):  
Zeta Potential ◽  
Isoelectric Point ◽  
Carboxyl Groups ◽  
Chemical Modifications ◽  
Electrokinetic Properties ◽  
Chemically Modified ◽  
Ph Values ◽  
Electrochemical Double Layer ◽  
Jute Fabrics ◽  
Oxidatively Modified

This work aims to study the alkali and oxidatively modified jute fabrics? electrokinetic properties. In contrast to control fabric, chemically modified jute fabrics have a small positive zeta potential in a basic pH range which can be attributed to the presence of sodium cations (originating from mentioned chemical modifications) on their surfaces. At lower pH values, samples modified under milder alkali and oxidative conditions have about 2.2-3.5 times lower zeta potential since the protonation process leads to the formation of higher positive charge in the electrochemical double layer causing higher adsorption of Cl- ions (originating from the electrolyte). On the other hand, more intensive chemical modifications increased the zeta potential at lower pH values due to the increased amount of carboxyl groups and fibers? ability for water retention and hence swelling. The isoelectric point of fabrics having lower zeta potential than control fabric was shifted toward higher pH values pointing out lower contribution of fabrics? surface acidic groups. In the case of extensive oxidation conditions (60 and 90 min), the isoelectric point was shifted toward lower pH values as a result of lignina removal and mentioned higher availability of newly formed carboxyl groups.

Isoelectric forms of clusterin isolated from ram rete testis fluid and from secretions of primary cultures of ram and rat Sertoli-cell-enriched preparations

1984 ◽  
Vol 62 (6) ◽  
pp. 456-461 ◽  
Author(s):  
O. W. Blaschuk ◽  
I. B. Fritz
Keyword(s):  
Sialic Acid ◽  
Granulosa Cell ◽  
Sertoli Cell ◽  
Isoelectric Point ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Primary Cultures ◽  
Rete Testis ◽  
Ph Values ◽  
A Cell

Clusterin, a cell aggregating factor isolated from ram rete testis fluid (RTF), is shown to contain 14.7% hexoses, 13.6% glucosamine, and 7.9% sialic acid. The isoelectric point (pI) of the predominant electrophoretic form of clusterin from ram RTF is 3.7. After treatment with neuraminidase, the pI values become more basic, with the majority of the material being eluted from a chromatofocusing column at pH values between 4.9 and 5.1. Intact clusterin binds quantitatively to wheat germ agglutinin – Sepharose 6 MB, but after treatment with neuraminidase only 49% specifically binds. Clusterin isolated from proteins secreted by primary cultures of ram Sertoli-cell-enriched preparations was shown to have properties similar to those of intact clusterin isolated from ram RTF. In contrast, clusterin isolated from proteins secreted by primary cultures of rat Sertoli- or granulosa-cell-enriched preparations has isoelectric forms which more closely resemble those of neuraminidase-treated ram clusterin.

Formation mechanism of spherical oxide particles containing dye

1999 ◽  
Vol 14 (5) ◽  
pp. 2088-2091
Author(s):  
Sixin Wu ◽  
Congshan Zhu
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Formation Mechanism ◽  
Isoelectric Point ◽  
Sol Gel ◽  
Diameter Distribution ◽  
Maximum Particle Size ◽  
Maximum Particle ◽  
Oxide Particles ◽  
Positively Charged

2-[3-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidine)-1-propenyl]-1,3,3-trimethyl-3H-indolium idoide (HICI) dye-doped SiO2 particles were synthesized by sol-gel method. Dimension, diameter, distribution, and homogeneity of the particles are closely related to the positively charged dye concentration, corresponding to the zeta potential of the particles. When the dye concentration reaches about 7.8 × 10−4 mol/mol SiO2, corresponding to the isoelectric point of the particles, the maximum particle size and the most homogeneity can be reached.

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