Polarographic investigation of the stability of tin(II) solutions in the presence of some stabilizing agents

1981 ◽  
Vol 130 (1) ◽  
pp. 133-140 ◽  
Author(s):  
Stefan Glodowski ◽  
Zenon Kublik
Keyword(s):  
Stabilizing Agents ◽  
Polarographic Investigation ◽  
The Stability

Heavy Metal Removal in the Presence of Colloid-Stabilizing Organic Material and Complexing Agents

1986 ◽  
Vol 18 (1) ◽  
pp. 19-29 ◽  
Author(s):  
I. Licskó ◽  
I. Takács
Keyword(s):  
Heavy Metals ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Colloidal Dispersion ◽  
Laboratory Model ◽  
Complexing Agents ◽  
Stabilizing Agents ◽  
Removal Of Heavy Metals ◽  
Alkaline Conditions ◽  
The Stability

It has been established in laboratory model experiments that the removal of dissolved heavyimetals from wastewaters is rendered more difficult in the presence of colloid-stabilizing agents. This unfavourable effect can be eliminated by the addition of Mg2+ ions and the adjustment to a fairly high pH. By increasing the concentration of Mg2+ ions, the pH necessary for destroying the stability of colloidal dispersion can be lowered. These findings also apply to the combined removal of different heavy metals (Cu, Zn, Cr(III), Ni, Cd). In alkaline conditions, in the presence of ammonium salts, some heavy metals (Cu, Zn, Ni) form high stability amine complexes. A higher pH is necessary for the breakdown of these complexes and the satisfactory removal of heavy metals.

scholarly journals Synthesis of Copper Nanoparticles Stabilized with Organic Ligands and Their Antimicrobial Properties

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2846
Author(s):  
Noemi Jardón-Maximino ◽  
Marissa Pérez-Alvarez ◽  
Gregorio Cadenas-Pliego ◽  
Luis E. Lugo-Uribe ◽  
Christian Cabello-Alvarado ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Chemical Reduction ◽  
Synthesis Method ◽  
Antimicrobial Properties ◽  
Stabilizing Agents ◽  
Copper Sulfate Pentahydrate ◽  
The Stability ◽  
High Yields ◽  
Zeta Potential Analysis

In this work, we report the synthesis of copper nanoparticles (Cu NPs), employing the chemical reduction method in an aqueous medium. We used copper sulfate pentahydrate (CuSO4·5H2O) as a metallic precursor; polyethylenimine (PEI), allylamine (AAM), and 4-aminobutyric acid (AABT) as stabilizing agents; and hydrated hydrazine as a reducing agent. The characterization of the obtained nanoparticles consisted of X-ray, TEM, FTIR, and TGA analyses. Through these techniques, it was possible to detect the presence of the used stabilizing agents on the surface of the NPs. Finally, a zeta potential analysis was performed to differentiate the stability of the nanoparticles with a different type of stabilizing agent, from which it was determined that the most stable nanoparticles were the Cu NPs synthesized in the presence of the PEI/AAM mixture. The antimicrobial activity of Cu/PEI/AABT toward P. aeruginosa and S. aureus bacteria was high, inhibiting both bacteria with low contact times and copper concentrations of 50–200 ppm. The synthesis method allowed us to obtain Cu NPs free of oxides, stable to oxidation, and with high yields. The newly functionalized Cu NPs are potential candidates for antimicrobial applications.

INFLUENCE OF STERICALLY STABILIZING AGENTS ON THE STABILITY OF FAT EMULSIONS

1990 ◽  
Vol 42 (S1) ◽  
pp. 137P-137P ◽  
Author(s):  
J. S. Lucks ◽  
B. W. Muller ◽  
R. H. Muller
Keyword(s):  
Stabilizing Agents ◽  
Fat Emulsions ◽  
The Stability

scholarly journals Rigidity of microtubules is increased by stabilizing agents.

1995 ◽  
Vol 130 (4) ◽  
pp. 909-917 ◽  
Author(s):  
B Mickey ◽  
J Howard
Keyword(s):  
Mechanical Properties ◽  
Flexural Rigidity ◽  
Mechanical Strain ◽  
Microtubule Depolymerization ◽  
Stabilizing Agents ◽  
Static Mechanical ◽  
Antimitotic Drug ◽  
Dynamic Structures ◽  
The Stability

Microtubules are rigid polymers that contribute to the static mechanical properties of cells. Because microtubules are dynamic structures whose polymerization is regulated during changes in cell shape, we have asked whether the mechanical properties of microtubules might also be modulated. We measured the flexural rigidity, or bending stiffness, of individual microtubules under a number of different conditions that affect the stability of microtubules against depolymerization. The flexural rigidity of microtubules polymerized with the slowly hydrolyzable nucleotide analogue guanylyl-(alpha, beta)-methylene-diphosphonate was 62 +/- 9 x 10(-24) Nm2 (weighted mean +/- SEM); that of microtubules stabilized with tau protein was 34 +/- 3 x 10(-24) Nm2; and that of microtubules stabilized with the antimitotic drug taxol was 32 +/- 2 x 10(-24) Nm2. For comparison, microtubules that were capped to prevent depolymerization, but were not otherwise stabilized, had a flexural rigidity of 26 +/- 2 x 10(-24) Nm2. Decreasing the temperature from 37 degrees C to approximately 25 degrees C, a condition that makes microtubules less stable, decreased the stiffness of taxol-stabilized microtubules by one-third. We thus find that the more stable a microtubule, the higher its flexural rigidity. This raises the possibility that microtubule rigidity may be regulated in vivo. In addition, the high rigidity of an unstabilized, GDP-containing microtubule suggests that a large amount of energy could be stored as mechanical strain energy in the protein lattice for subsequent force generation during microtubule depolymerization.

scholarly journals Synthesis and Optical Properties of Colloidal Gold Nanoparticles for Biomedical Applications

2011 ◽  
Vol 21 (1) ◽  
pp. 63 ◽  
Author(s):  
Nghiem Thi Ha Lien ◽  
Vu Xuan Hoa ◽  
Vu Thi Thuy Duong ◽  
Nguyen Van Tinh ◽  
Tran Hong Nhung
Keyword(s):  
Gold Nanoparticles ◽  
Colloidal Gold ◽  
Biomedical Applications ◽  
Strong Dependence ◽  
Trisodium Citrate ◽  
Visible Range ◽  
Chloroauric Acid ◽  
Stabilizing Agents ◽  
Colloidal Gold Nanoparticles ◽  
The Stability

The gold nanoparticle solutions are well known as an extremely sensitive biomedical analytical tool due to the strong dependence of their absorption in the visible range on the environment. In this work, the colloidal nano golds were synthesized from metal precursor chloroauric acid (HAuCl4) using trisodium citrate dehydrate (C6H5O7Na3) as reducing and stabilizing agents. The optical characterization - absorption of colloidal gold solution have been investigated under the different synthetic conditions such as: reducing agent concentration, concentration of auric ion, pH, duration of reaction and aging time. The results show that the absorption and the stability of the colloidal gold nanoparticles depend robustly on the synthetic conditions and pH of environment.

scholarly journals SAXS Reveals the Stabilization Effects of Modified Sugars on Model Proteins

Life ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 123
Author(s):  
Astra Piccinini ◽  
Eva C. Lourenço ◽  
Osvaldo S. Ascenso ◽  
Maria Rita Ventura ◽  
Heinz Amenitsch ◽  
...  
Keyword(s):  
X Ray ◽  
Stabilizing Agents ◽  
Remote Areas ◽  
X Ray Scattering ◽  
Stabilization Effect ◽  
Novel Method ◽  
High Concentrations ◽  
The Stability ◽  
Denatured States ◽  
Ph Variations

Many proteins are usually not stable under different stresses, such as temperature and pH variations, mechanical stresses, high concentrations, and high saline contents, and their transport is always difficult, because they need to be maintained in a cold regime, which is costly and very challenging to achieve in remote areas of the world. For this reason, it is extremely important to find stabilizing agents that are able to preserve and protect proteins against denaturation. In the present work, we investigate, by extensively using synchrotron small-angle X-ray scattering experiments, the stabilization effect of five different sugar-derived compounds developed at ExtremoChem on two model proteins: myoglobin and insulin. The data analysis, based on a novel method that combines structural and thermodynamic features, has provided details about the physical-chemical processes that regulate the stability of these proteins in the presence of stabilizing compounds. The results clearly show that some modified sugars exert a greater stabilizing effect than others, being able to maintain the active forms of proteins at temperatures higher than those in which proteins, in the absence of stabilizers, reach denatured states.

scholarly journals Green synthesis and stabilization of earthworm-like gold nanostructure and quasi-spherical shape using Caesalpinia sappan Linn. extract

2018 ◽  
Vol 7 (5) ◽  
pp. 424-432 ◽  
Author(s):  
Widsanusan Chartarrayawadee ◽  
Chee O. Too ◽  
Sukunya Ross ◽  
Gareth M. Ross ◽  
Kanlaya Jumpatong ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Green Synthesis ◽  
Spherical Shape ◽  
Colloidal Solutions ◽  
Tem Analysis ◽  
Caesalpinia Sappan ◽  
Synthesis Of Nanoparticles ◽  
Stabilizing Agents ◽  
Transmission Electron ◽  
The Stability

AbstractGreen synthesis of nanoparticles (NPs) has received much attention due to biocompatibility and being facile and eco-friendly.Caesalpinia sappanLinn. (CS) is a plant found in Southeast Asia and is commonly known as sappan wood. In this research, we are the first to successfully use CS extract as reducing and stabilizing agents for the green synthesis of gold NPs (AuNPs). Colloidal solutions of AuNPs after reduction show natural red-wine and dark purple color depending on the size of AuNPs, without the interference of the orange/reddish-orange color from the CS extract. The concentration of CS was investigated for the formation and stabilization of AuNPs in colloidal solution (i.e. morphology, size and zeta potential). It was found that the optimized concentration of the reducing agent for the green synthesis of AuNPs was in the range of 0.004–0.04 wt% of CS. As the concentration of CS was increased, the sizes of AuNPs decreased due to the adsorption and stabilizing effect of CS. Transmission electron microscopy (TEM) analysis showed differences in size and shape of the NPs with earthworm and quasi-spherical characteristics. The zeta potential of AuNPs synthesized in the presence of CS was approximately in the range of −10 mV to −20 mV, indicating the stability of AuNPs synthesized by CS.

scholarly journals Effect of cement on the stability and the wearrance of soils in earthworks

2018 ◽  
Vol 149 ◽  
pp. 02022
Author(s):  
Bendimerad Karam Feth-Allah ◽  
Zadjaoui Abdeldjalil
Keyword(s):  
Sustainable Development ◽  
Water Regime ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Appreciable Change ◽  
Stabilizing Agents ◽  
Long Time ◽  
Technical Guide ◽  
The Stability

The technique of soil treatment is known for a long time, currently, during the big motorway programs this technique is experiencing important to reach zero imprints and zero deposit in a context of sustainable development or the socio-economic and environmental challenges incite during the work of earthworks. Our work puts highlights the treatment of fine soils in westerns region of Algeria (wilaya of Tlemcen, a project to construct a payment station for the entry of the wilaya (sample n°1), electrical post 400/200 KVA in the locality Ain Fetah (sample n°2)), belonging to the class A3h (very plastic clay) according to the Technical Guide for Earthworks (GTR), whose use in the raw state would involve great risks of stability because of their plasticity (Ip > 20%) and their low capacity (CBR < 25) according to the Specification of the Algerian Loads, Technical Clauses (CSDCA-CT) by the incorporation of the stabilizing agents, for example the variant of locally manufactured CEM II / A42.5N composite cement, in order to define their behaviours by examining the variation of their characteristics determined according to the Algerian standards and at a ambient temperature according to the additive dosage and to contribute to the deduction of the interest of the method demonstrated previously. The results obtained clearly show a tendency the rearrange classification of the soils studied according to the unified system en proportion whit to the additive dosage (0 to 14%) in view of the appreciable change in the plasticity behaviour, which results in a decrease in the plasticity index, going up to 37.7% and the 11% of the maximum dry density accompanied by a satisfactory increase in the suitability of the materials to be supported a load with different moisture content and changes in water regime exceeds 100%. Given the unavailability of other exploitable deposits near the site and the experimental results obtained, the variant of the treatment seems feasible.

scholarly journals COLCHICINE-BINDING PROTEIN AND THE SECRETION OF THYROID HORMONE

1972 ◽  
Vol 54 (1) ◽  
pp. 157-165 ◽  
Author(s):  
John A. Williams ◽  
J. Wolff
Keyword(s):  
Cyclic Amp ◽  
Binding Protein ◽  
Thyroid Stimulating Hormone ◽  
Ph Optimum ◽  
Similar Time ◽  
Stabilizing Agents ◽  
Time Courses ◽  
The Stability ◽  
Thyroid Secretion

The role of microtubules in the thyrotropin- or adenosine 3',5' cyclic monophosphate (cyclic AMP)-stimulated accumulation of cytoplasmic colloid droplets and secretion of iodine from the mouse thyroid gland has been investigated by means of different classes of agents that affect the stability of microtubules. The onset of inhibition of secretion by colchicine, the uptake of colchicine-3H by thyroid lobes, and the binding of colchicine-3H to thyroidal soluble protein are shown to have similar time courses Colloid droplet accumulation is also inhibited and does not readily resume upon removal of colchicine from the medium. This appears to be due to the slow washout of the drug (t½ ∼ hr). Thyroids contain a soluble colchicine-binding protein that resembles microtubule proteins of other tissues with respect to apparent Km for colchicine, pH optimum, and stability characteristics Colchicine analogues inhibit iodine secretion and colchicine binding in a parallel manner and as a function of their antimitotic potencies. Microtubule-stabilizing agents such as hexylene glycol and D2O also inhibit secretion. Thus, inhibition of thyroid secretion by antimitotic agents appears to be mediated by an effect on microtubules. The inhibitory locus of colchicine inhibition occurs after the generation of cyclic AMP, since stimulation of secretion by this nucleotide is blocked by colchicine, whereas thyroid-stimulating hormone—induced accumulation of cyclic AMP is not affected. Thus, the functioning microtubule appears to play a role in the induction of colloid endocytosis.

Open discussion

1982 ◽  
Vol 99 ◽  
pp. 605-613
Author(s):  
P. S. Conti
Keyword(s):  
Buenos Aires ◽  
Large Mass ◽  
List Type ◽  
Common Phenomenon ◽  
Open Discussion ◽  
The Stability ◽  
Ring Nebulae

Conti: One of the main conclusions of the Wolf-Rayet symposium in Buenos Aires was that Wolf-Rayet stars are evolutionary products of massive objects. Some questions:–Do hot helium-rich stars, that are not Wolf-Rayet stars, exist?–What about the stability of helium rich stars of large mass? We know a helium rich star of ∼40 MO. Has the stability something to do with the wind?–Ring nebulae and bubbles : this seems to be a much more common phenomenon than we thought of some years age.–What is the origin of the subtypes? This is important to find a possible matching of scenarios to subtypes.

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