DEPOLYMERIZATION OF DEXTRAN BY HYDROGEN PEROXIDE

1955 ◽  
Vol 33 (1) ◽  
pp. 448-452 ◽  
Author(s):  
Irving Levi ◽  
Ezra Lozinski
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Blood Plasma ◽  
Dilute Solutions ◽  
Pressure Time ◽  
Wide Range ◽  
Aqueous Dextran

It was observed that when very dilute solutions of hydrogen peroxide were employed for the purpose of destroying pyrogens in aqueous dextran solutions, a marked depolymerization of the polysaccharide molecule occurred. Further study demonstrated this effect to occur over a wide range of temperature, pressure, time, and concentration of hydrogen peroxide. It was therefore possible to use hydrogen peroxide in place of the usual hydrolytic agents, such as acids, for the depolymerization of native dextran to smaller molecular weight fragments suitable for use as a blood plasma extender.

DEPOLYMERIZATION OF DEXTRAN BY HYDROGEN PEROXIDE

1955 ◽  
Vol 33 (3) ◽  
pp. 448-452 ◽  
Author(s):  
Irving Levi ◽  
Ezra Lozinski
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Blood Plasma ◽  
Dilute Solutions ◽  
Pressure Time ◽  
Wide Range ◽  
Aqueous Dextran

It was observed that when very dilute solutions of hydrogen peroxide were employed for the purpose of destroying pyrogens in aqueous dextran solutions, a marked depolymerization of the polysaccharide molecule occurred. Further study demonstrated this effect to occur over a wide range of temperature, pressure, time, and concentration of hydrogen peroxide. It was therefore possible to use hydrogen peroxide in place of the usual hydrolytic agents, such as acids, for the depolymerization of native dextran to smaller molecular weight fragments suitable for use as a blood plasma extender.

Origin and Use of Hydrogen Peroxide in Neurosurgery

Neurosurgery ◽  
2021 ◽  
Author(s):  
David Bailey ◽  
Elias B Rizk
Keyword(s):  
Hydrogen Peroxide ◽  
Hemostatic Agent ◽  
Medical Field ◽  
Wide Range ◽  
Actual Effectiveness ◽  
Fatal Complications

Abstract Hydrogen peroxide (H2O2) is a chemical with a wide range of applications. This includes its use in the medical field, in which its use has been ubiquitous but is most useful as an antiseptic and in achieving hemostasis. Neurosurgeons have been using H2O2 for well over a century, primarily for its hemostatic and antiseptic effects. This is in spite of the fact that the actual effectiveness of H2O2 as an antiseptic is questionable, and its use, in general, may be more dangerous than it appears. We review the application of H2O2 in medicine generally and, more specifically, in neurosurgery. This review outlines the reasoning behind the use of H2O2 as an antiseptic and details why it may not be as effective as one might think. We also detail its use as a hemostatic agent in neurosurgery, reviewing a number of techniques in which it has been useful in this role. Finally, we review the documented cases of complications associated with the use of H2O2 in neurosurgery. Ultimately, we conclude that the use of H2O2 in neurosurgery be reconsidered because of its lack of effectiveness as an antiseptic and potentially fatal complications.

scholarly journals Reactivity and Chemical Sintering of Carey Lea Silver Nanoparticles

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1525
Author(s):  
Sergey Vorobyev ◽  
Elena Vishnyakova ◽  
Maxim Likhatski ◽  
Alexander Romanchenko ◽  
Ivan Nemtsev ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Silver Nanoparticles ◽  
Flexible Electronics ◽  
Photoelectron Spectroscopy ◽  
Colloidal Solutions ◽  
Ag Nps ◽  
Wide Range ◽  
Carboxylic Groups ◽  
The Media ◽  
Sulfide Ions

Carey Lea silver hydrosol is a rare example of very concentrated colloidal solutions produced with citrate as only protective ligands, and prospective for a wide range of applications, whose properties have been insufficiently studied up to now. Herein, the reactivity of the immobilized silver nanoparticles toward oxidation, sulfidation, and sintering upon their interaction with hydrogen peroxide, sulfide ions, and chlorocomplexes of Au(III), Pd(II), and Pt(IV) was investigated using SEM and X-ray photoelectron spectroscopy (XPS). The reactions decreased the number of carboxylic groups of the citrate-derived capping and promoted coalescence of 7 nm Ag NPs into about 40 nm ones, excluding the interaction with hydrogen peroxide. The increased nanoparticles form loose submicrometer aggregates in the case of sulfide treatment, raspberry-like micrometer porous particles in the media containing Pd(II) chloride, and densely sintered particles in the reaction with inert H2PtCl6 complexes, probably via the formation of surface Ag-Pt alloys. The exposure of Ag NPs to HAuCl4 solution produced compact Ag films along with nanocrystals of Au metal and minor Ag and AgCl. The results are promising for chemical ambient temperature sintering and rendering silver-based nanomaterials, for example, for flexible electronics, catalysis, and other applications.

NOM and MIB, who wins in the competition for activated carbon adsorption sites?

2004 ◽  
Vol 49 (9) ◽  
pp. 257-265 ◽  
Author(s):  
C. Hepplewhite ◽  
G. Newcombe ◽  
D.R.U. Knappe
Keyword(s):  
Molecular Weight ◽  
Activated Carbons ◽  
Background Concentration ◽  
Low Molecular Weight ◽  
Activated Carbon Adsorption ◽  
Microporous Carbons ◽  
Adsorption Sites ◽  
Carbon Adsorption ◽  
Competitive Mechanism ◽  
Wide Range

The adsorption of an odour compound common in drinking water, 2-methylisoborneol (MIB), was studied on two activated carbons in the presence of 13 well-characterised natural organic matter (NOM) solutions. It was found that, although the carbons and the NOM solutions had a wide range of characteristics, the major competitive mechanism was the same in all cases. The low molecular weight NOM compounds were the most competitive, participating in a direct competition with the MIB molecule for adsorption sites. Equivalent background concentration (EBC) calculations indicated a relatively low concentration of directly competing compounds in the NOM. Some evidence of pore restriction was also seen, with microporous carbons most affected by low molecular weight NOM, and mesoporous carbons impacted by the higher molecular weight compounds.

scholarly journals Interaction Between Titanium Implant Surfaces and Hydrogen Peroxide in Biologically Relevant Environments

2004 ◽  
Vol 823 ◽  
Author(s):  
Julie Muyco ◽  
Timothy Ratto ◽  
Christine Orme ◽  
Joanna McKittrick ◽  
John Frangos
Keyword(s):  
Hydrogen Peroxide ◽  
Raman Spectroscopy ◽  
Atomic Force Microscope ◽  
Titanium Implant ◽  
Dilute Solutions ◽  
Interaction Layer ◽  
Biologically Relevant ◽  
Light Passing ◽  
Atomic Force ◽  
Force Curves

AbstractTitanium was exposed to dilute solutions of hydrogen peroxide (H2O2) to better characterize the interaction at the interface between the solution and metal. The intensity of light passing through films of known thickness of titanium on quartz was measured as a function of time in contact with H2O2in concentrations of 0.3% and 1.0%. An atomic force microscope (AFM) was used to record deflection-distance (force) curves as a probe approached the interface of titanium in contact with solution containing 0.3% of H2O2. The interaction layer measured using AFM techniques was much greater than the thickness of the titanium films used in this study. Raman spectroscopy taken during interaction shows the emergence of a Ti-peroxy gel and titania after 2 hours in contact with 0.3% H2O2solution.

Effect of Block Molecular Weight on the Mechanical Properties of PA1010-b-PEG Segmented Block Copolymers

2012 ◽  
Vol 512-515 ◽  
pp. 2127-2130
Author(s):  
Li Huo ◽  
Cai Xia Dong
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Block Copolymers ◽  
Microphase Separation ◽  
Soft Segment ◽  
Mechanical Measurements ◽  
Wide Range ◽  
Hard Block ◽  
Higher Temperature ◽  
Hard Segments

The mechanical properties were investigated of a series of PA-PEG thermalplastic elastomer based on PA1010 and polytetramethylene glycol (PEG) with varying hard and soft segment content. Dynamic mechanical measurements of these polymers have carried out over a wide range of temperatures. The block copolymers exhibit three peaks, designated as α, β and γ in the tanδ-temperature curve. The α transition shifts to higher temperature with increasing hard block molecular weight. However, at a constant hard molecular weight, the α transition shifts to higher temperature and the damping increases on increasing the soft segment molecular weight. DMA results show that the block copolymers exhibit a microphase separation structure and both soft and hard segments were found to be crystallizable. The degree of phase separation increases with increasing hard block molecular weight.

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