Some studies in inorganic complexes. II. Bismuth(III)

1958 ◽  
Vol 11 (4) ◽  
pp. 415 ◽  
Author(s):  
GJ Sutton
Keyword(s):  
Molecular Weight ◽  
Coordination Complex ◽  
Inorganic Complexes ◽  
Covalent Complex

Complexes of bismuth halides and the ligand o-phenylenebisdimethylarsine have been prepared and studied. Conductivity and molecular weight determinations show that they are 5-covalent monomers of the type BiX3.diarsine in which X is halogen. A study was also made of the &covalent complex Bi diarsine3(ClO4)3. No coordination complex of phenanthroline was obtained, but some phenanthrolinium and dipyridylium salts of the type [phenan H.H2O]+[BiX4]- and [dipy H.H2O]+[BiCl4]- were investigated.

Covalent Complexes Between Low Molecular Weight Heparin Fragments and Antithrombin III – Inhibition Kinetics and Turnover Parameters

1983 ◽  
Vol 49 (02) ◽  
pp. 109-115 ◽  
Author(s):  
M Hoylaerts ◽  
E Holmer ◽  
M de Mol ◽  
D Collen
Keyword(s):  
Molecular Weight ◽  
Half Life ◽  
Low Molecular Weight Heparin ◽  
Antithrombin Iii ◽  
Factor Xa ◽  
Life Time ◽  
Low Molecular Weight ◽  
High Affinity ◽  
Plasma Half Life ◽  
Covalent Complex

SummaryTwo high affinity heparin fragments (A/r 4,300 and M, 3,200) were covalently coupled to antithrombin III (J. Biol. Chem. 1982; 257: 3401-3408) with an apparent 1:1 stoichiometry and a 30-35% yield.The purified covalent complexes inhibited factor Xa with second order rate constants very similar to those obtained for antithrombin III saturated with these heparin fragments and to that obtained for the covalent complex between antithrombin III and native high affinity heparin.The disappearance rates from plasma in rabbits of both low molecular weight heparin fragments and their complexes could adequately be represented by two-compartment mammillary models. The plasma half-life (t'/j) of both low Afr-heparin fragments was approximately 2.4 hr. Covalent coupling of the fragments to antithrombin III increased this half-life about 3.5 fold (t1/2 ≃ 7.7 hr), approaching that of free antithrombin III (t1/2 ≃ 11 ± 0.4 hr) and resulting in a 30fold longer life time of factor Xa inhibitory activity in plasma as compared to that of free intact heparin (t1/2 ≃ 0.25 ± 0.04 hr).

A Photoluminescent Au(I)/Ag(I)/PNN coordination complex for Relatively Rapid and Reversible Alcohol Sensing

2021 ◽  
Author(s):  
Yanhui Tao ◽  
Yuwei Wang ◽  
Shengnan Hu ◽  
David James Young ◽  
Chengrong Lu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Coordination Complex ◽  
Trinuclear Complex ◽  
Low Molecular Weight ◽  
Radiative Relaxation ◽  
Π Interactions

Trinuclear complex [Au2Ag(dppmaphen)2(CN)2]PF6 photoluminesces on exposure to low molecular weight alcohols. This emission is likely due to C-H···π interactions between the analyte and –PPh2 group, that inhibits non-radiative relaxation of...

Some studies in inorganic complexes. IV. Titanium(III) and Titanium(IV)

1959 ◽  
Vol 12 (2) ◽  
pp. 122 ◽  
Author(s):  
GJ Sutton
Keyword(s):  
Molecular Weight ◽  
Conductivity Measurements ◽  
Titanium Complexes ◽  
Inorganic Complexes

The titanium complexes TiCl3.D.H2O, TiBr3.D.H2O, TiCl4.D, and TiBr4.D, In which D is o-phenylenebisdimethylarsine. have been prepared and studied. By means of conductivity and molecular weight measurements, it has been shown that they are 6-covalent non-electrolytes. The thiocyanato complexes [NH4][Ti(SCN)4(H2O)2,], [NH4][Ti(SCN)4], and [NH4][Ti(SCN)4OH.H2O] were also prepared and their structures verified by conductivity measurements.

Some Studies in Inorganic Complexes. V. Mercury(II)

1959 ◽  
Vol 12 (4) ◽  
pp. 637 ◽  
Author(s):  
GJ Sutton
Keyword(s):  
Molecular Weight ◽  
Absorption Spectra ◽  
Ultra Violet ◽  
Inorganic Complexes

A study has been made of mercury(II) complexes of ethylenediamine, 1,10-phenanthroline, and 2,2'-dipyridyl. By means of conductance and molecular weight measurements it has been shown that complexes of the type HgX2.B and HgY.B, in which B is the base, X is halogen or nitrite, and Y is oxalate or sulphate, are 4-covalent non-electrolytes. The absorption spectra of the halogen complexes in the near ultra-violet range are characteristic of the chelate with a shift of absorption to longer wavelengths. Bisphenanthroline and bisdipyridyl complexes of mercury(II) were also investigated.

Some studies in inorganic complexes. III. Antimony(III), Arsenic(III), and Phosphorus (III)

1958 ◽  
Vol 11 (4) ◽  
pp. 420 ◽  
Author(s):  
GJ Sutton
Keyword(s):  
Molecular Weight ◽  
Chelating Ligand ◽  
Inorganic Complexes

A study has been made of complexes of the halides of antimony, arsenic, and phosphorus with the chelating ligand o-phenylenebisdimethylarsine. Conductivity and molecular weight determinations in nitrobenzene show that these are &covalent monomers of the type SbX3.D, AsX3D, and PX3.D, in which X is halogen and D is diarsine. However, in this solvent there is a progressive tendency towards ionization from Sb to P and from Cl to I, so that the iodo complexes of arsenic and phosphorus are partly ionized as [AsI2D]+I- and [PI2D]+I- respectively. This is also in accordance with the preparation of the perchlorate [AsI2D]+[ClO4]-.H2O from the complex [AsI2D]+I-. A study was also made of the phenanthrolinium salts [phenanH.H2O]+[SbX4]-, although no compounds were obtained in which the base is coordinated to the metal.

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.

The External Shape of Human γ GI Immunoglobulin from Crystal Sections

1971 ◽  
Vol 29 ◽  
pp. 428-429
Author(s):  
L. W. Labaw
Keyword(s):  
Molecular Weight ◽  
Sodium Phosphate ◽  
Osmium Tetroxide ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
X Ray ◽  
Large Molecular Weight ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Crystallographic Axes

Crystals of a human γGl immunoglobulin have the external morphology of diamond shaped prisms. X-ray studies have shown them to be monoclinic, space group C2, with 2 molecules per unit cell. The unit cell dimensions are a = 194.1, b = 91.7, c = 51.6Å, 8 = 102°. The relatively large molecular weight of 151,000 and these unit cell dimensions made this a promising crystal to study in the EM.Crystals similar to those used in the x-ray studies were fixed at 5°C for three weeks in a solution of mother liquor containing 5 x 10-5M sodium phosphate, pH 7.0, and 0.03% glutaraldehyde. They were postfixed with 1% osmium tetroxide for 15 min. and embedded in Maraglas the usual way. Sections were cut perpendicular to the three crystallographic axes. Such a section cut with its plane perpendicular to the z direction is shown in Fig. 1.This projection of the crystal in the z direction shows periodicities in at least four different directions but these are only seen clearly by sighting obliquely along the micrograph.

Conformation of eukaryotic ribosomal RNAs

1983 ◽  
Vol 41 ◽  
pp. 592-593
Author(s):  
M. Boublik ◽  
G. Thornton ◽  
G. Oostergetel ◽  
J.F. Hainfeld ◽  
J.S. Wall
Keyword(s):  
Molecular Weight ◽  
Mass Measurement ◽  
Carbon Film ◽  
Structural Complexity ◽  
Scanning Transmission Electron Microscope ◽  
Electron Microscopic ◽  
Pure Nitrogen ◽  
Freeze Dried ◽  
Scanning Transmission ◽  
Partially Unfolded

Understanding the structural complexity of ribosomes and their role in protein synthesis requires knowledge of the conformation of their components - rRNAs and proteins. Application of dedicated scanning transmission electron microscope (STEM), electrical discharge of the support carbon film in an atmosphere of pure nitrogen, and determination of the molecular weight of individual rRNAs enabled us to obtain high resolution electron microscopic images of unstained freeze-dried rRNA molecules from BHK cells in a form suitable for evaluation of their 3-D structure. Preliminary values for the molecular weight of 28S RNA from the large and 18S RNA from the small ribosomal subunits as obtained by mass measurement were 1.84 x 106 and 0.97 x 106, respectively. Conformation of rRNAs consists, in general, of alternating segments of intramolecular hairpin stems and single stranded loops in a proportion which depends on their ionic environment, the Mg++ concentration in particular. Molecules of 28S RNA (Fig. 1) and 18S RNA (not shown) obtained by freeze-drying from a solution of 60 mM NH+4 acetate and 2 mM Mg++ acetate, pH 7, appear as partially unfolded coils with compact cores suggesting a high degree of ordered secondary structure.

The Structure of Radiation Cross-Linked Poly (ethylene oxide) Gels

1971 ◽  
Vol 29 ◽  
pp. 76-77
Author(s):  
C. E. Cluthe ◽  
G. G. Cocks
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Parallel Plate ◽  
Average Molecular Weight ◽  
Radical Reaction ◽  
Free Radical Reaction ◽  
Nitrogen Gas ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Initial Viscosity

Aqueous solutions of a 1 weight-per cent poly (ethylene oxide) (PEO) were degassed under vacuum, transferred to a parallel plate viscometer under a nitrogen gas blanket, and exposed to Co60 gamma radiation. The Co60 source was rated at 4000 curies, and the dose ratewas 3.8x105 rads/hr. The poly (ethylene oxide) employed in the irradiations had an initial viscosity average molecular weight of 2.1 x 106.The solutions were gelled by a free radical reaction with dosages ranging from 5x104 rads to 4.8x106 rads.

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