Three-component model systems based on egg phosphatidylcholine and cholesterol in the presence of silver nanoparticles

2021 ◽  
Vol 1 (4) ◽  
pp. 67-72
Author(s):  
I. V. Milaeva ◽  
◽  
S. Yu. Zaytsev ◽  
Keyword(s):  
Particle Size ◽  
Practical Importance ◽  
Antimicrobial Properties ◽  
Particle Diameter ◽  
Living Organism ◽  
Model Systems ◽  
Ionic Form ◽  
Average Particle ◽  
Antimicrobial Drugs ◽  
Destructive Effect

Due to the significant increase in the resistance of microorganisms to the action of medicines, primarily antibiotics, the search for other antibacterial agents, including the preparation of silver-based drugs, is extremely important. In small concentrations (50 mcg/l), silver is safe for a living organism, but shows a destructive effect against most bacteria and viruses. The use of silver in the form of nanoparticles (NPAg) can reduce its concentration by hundreds of times compared to the ionic form, while preserving all its antimicrobial properties. An important task is both the development of non-toxic antimicrobial drugs based on silver NP that retain their bactericidal properties and stability over a long period, and the elucidation of the mechanisms of interaction of NPAg with cells and tissues of a living organism. The aim of this work was to study the effect of specified concentrations of NPAg on the structure (size) of particles and surface tension (ST) of model systems obtained on the basis of crude egg phosphatidylcholine and cholesterol. In the work, mixtures of the following lipids were studied in detail: PCe1 – crude phosphatidylcholine, Chol – cholesterol. It was shown that under the influence of middle concentrations of NPAg (up to 0,3–0,5 rel. units) in samples with PCe1 significant changes in the particle size in the mixture occur. Moreover, in mixtures of Chol with PCe1, the addition of NPAg even at a low concentration (0,01 rel. units) already causes a decrease in the average particle diameter by 1,5 times. It has been shown that the presence of sufficiently large NPAg particles (at surface lifetimes from 0,5 to 5 s) gives higher ST values, and a change in the particle size leads to changes in ST: an increase in size – an increase in ST, a decrease in size – a decrease in ST. The equilibrium ST is apparently influenced by the presence of NPAg particles of different sizes in the sample and their ratio. A study of the interaction of NPAg with natural compounds, such as phospholipids, polysaccharides, proteins and peptides, is of great fundamental and practical importance.

scholarly journals Preparation of Polyetherimide Nanoparticles by a Droplet Evaporation-Assisted Thermally Induced Phase-Separation Method

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1548
Author(s):  
Peng Zhu ◽  
Huapeng Zhang ◽  
Hongwei Lu
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Phase Separation ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Droplet Evaporation ◽  
Average Particle ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Pei Nanoparticles

The droplet evaporation effect on the preparation of polyetherimide (PEI) nanoparticles by thermally induced phase separation (TIPS) was studied. PEI nanoparticles were prepared in two routes. In route I, the droplet evaporation process was carried out after TIPS. In route II, the droplet evaporation and TIPS processes were carried out simultaneously. The surface tension and shape parameters of samples were measured via a drop shape analyzer. The Z-average particle diameter of PEI nanoparticles in the PEI/dimethyl sulfoxide solution (DMSO) suspension at different time points was tested by dynamic light scattering, the data from which was used to determine the TIPS time of the PEI/DMSO solution. The natural properties of the products from both routes were studied by optical microscope, scanning electron microscope and transmission electron microscope. The results show that PEI nanoparticles prepared from route II are much smaller and more uniform than that prepared from route I. Circulation flows in the droplet evaporation were indirectly proved to suppress the growth of particles. At 30 °C, PEI solid nanoparticles with 193 nm average particle size, good uniformity, good separation and good roundness were obtained. Route I is less sensitive to temperature than route II. Samples in route I were still the accumulations of micro and nanoparticles until 40 °C instead of 30 °C in route II, although the particle size distribution was not uniform. In addition, a film structure would appear instead of particles when the evaporation temperature exceeds a certain value in both routes. This work will contribute to the preparation of polymer nanoparticles with small and uniform particle size by TIPS process from preformed polymers.

Minimum Particle Diameter of the Vanadium/Iron Co-Doped Nano TiO2 Transparent Hydrosol at Room Temperature

2014 ◽  
Vol 989-994 ◽  
pp. 611-614
Author(s):  
Ling Li ◽  
Wen Ming Zhang ◽  
Hua Yan Zhang ◽  
Zi Hao Xu ◽  
Sen Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Room Temperature ◽  
Raw Materials ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Ferric Nitrate ◽  
Average Particle ◽  
Hydrolysis Method ◽  
Vanadium Iron ◽  
Co Doped

Vanadium/iron co-doped nanoTiO2 transparent hydrosol with an average particle size of 3.8 nm was synthesized by a novel complexation-controlled hydrolysis method at room temperature and atmospheric pressure by using TiCl4, ferric nitrate, ammonium metavanadate, etc. as raw materials. The composition, phase structure, particle size, absorbance spectrum, and photocatalytic performance of samples were characterized by XRD, EDS, nanolaser particle size analyzer, and UV-Vis spectrophotometer. The photocatalytic properties of V/Fe doped TiO2 were studied through degrading acid 3R dye, and the results show that when the content of V/Fe was 0.5%, the degradation rate reached more than 96% under irridation for 60 min.

Gas-phase particle size distributions and lead loss during spray pyrolysis of (Bi,Pb)–Sr–Ca–Cu–O

1995 ◽  
Vol 10 (7) ◽  
pp. 1644-1652 ◽  
Author(s):  
Abhijit S. Gurav ◽  
Toivo T. Kodas ◽  
Jorma Joutsensaari ◽  
Esko I. Kauppincn ◽  
Riitta Zilliacus
Keyword(s):  
Particle Size ◽  
Spray Pyrolysis ◽  
Gas Phase ◽  
Phase Particle ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Processing Temperature ◽  
Average Particle ◽  
Size Distributions ◽  
Particle Size Distributions

Gas-phase particle size distributions and lead loss were measured during formation of (Bi,Pb)-Sr-Ca-Cu-O and pure PbO particles by spray pyrolysis at different temperatures. A differential mobility analyzer (DMA) in conjunction with a condensation particle counter (CPC) was used to monitor the gas-phase particle size distributions, and a Berner-type low-pressure impactor was used to obtain mass size distributions and size-classified samples for chemical analysis. For (Bi,Pb)-Sr-Ca-Cu-O, as the processing temperature was raised from 200 to 700 °C, the number average particle size decreased due to metal nitrate decomposition, intraparticle reactions forming mixed-metal oxides and particle densification. The geometric number mean particle diameter was 0.12 μm at 200 °C and reduced to 0.08 and 0.07 μm, respectively, at 700 and 900 °C. When the reactor temperature was raised from 700 and 800 °C to 900 °C, a large number (∼107 no./cm3) of new ultrafine particles were formed from PbO vapor released from the particles and the reactor walls. Particles made at temperatures up to 700 °C maintained their initial stoichiometry over the whole range of particle sizes monitorcd; however, those made at 800 °C and above were heavily depleted in lead in the size range 0.5–5.0 μm. The evaporative losses of lead oxide from (Bi,Pb)-Sr-Ca-Cu-O particles were compared with the losses from PbO particles to gain insight into the pathways involved in lead loss and the role of intraparticle processes in controlling it.

Use of Calixarene Host Molecules to Stabilize Quantum-confined Cadmium Sulfide Formation

1992 ◽  
Vol 272 ◽  
Author(s):  
Robin R. Chandler ◽  
Jeffery L. Coffer ◽  
C. David Gutsche ◽  
Iftikhar Alam ◽  
Hong Yang ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Diameter ◽  
Spectroscopic Studies ◽  
Average Particle ◽  
Average Particle Diameter ◽  
Absorption And Emission ◽  
Zinc Blende ◽  
High Resolution Tem ◽  
Quantum Confined ◽  
Macrocyclic Molecules

ABSTRACTWe describe here the use of calixarenes, methylene (-CH2-) linked phenolic macrocyclic molecules, to stabilize the formation of quantum-confined (Q-) CdS clusters. Specifically, we focus on the use of an amino-derivatized calixarene, para-[(dimethylamino)- methyl]calix[6]arene, to stabilize Q-CdS clusters which have been characterized by High Resolution TEM (HREM), as well as absorption and emission spectroscopies. Under typical preparative conditions, an average particle diameter of 36 Å is obtained. HREM, in combination with Selected Area Diffraction (SAD), confirms the structure of the clusters as zinc blende CdS. Spectroscopic studies using absorption and emission methods indicate that both particle size and cluster photophysics are sensitive to the ratio of CdS to calixarene.

Swelling of Latex Particles

1959 ◽  
Vol 32 (3) ◽  
pp. 814-824
Author(s):  
Maurice Morton ◽  
Samuel Kaizerman ◽  
Mary W. Altier
Keyword(s):  
Molecular Weight ◽  
Particle Size ◽  
Interfacial Energy ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Polystyrene Latex ◽  
Average Particle ◽  
Equilibrium Solubility ◽  
Latex Particles ◽  
Equilibrium Swelling

Abstract A theoretical relation has been derived for the equilibrium swelling of latex particles. The equilibrium solubility and rate of solution of solvents were measured on a series of polystyrene latex fractions of varying particle size. The solvents used were styrene, toluene, and chlorocyclohexane. It was found, as predicted by theory, that the equilibrium amount of solvent imbibed by latex particles is a direct function of the particle diameter and an inverse function of the interfacial energy at the surface of the particles. The molecular weight of the polymer has no effect on the equilibrium swelling, within the range from 100,000 to several million molecular weight units. The rate of imbibition of these solvents appears to be extremely rapid, indicating that equilibrium solubility would appear to be maintained in most polymerization reactions. The fact that a particular solvent is a “good” solvent for the polymer does not necessarily result in a greater swelling of the particles, since the solvent may show a higher interfacial energy against the aqueous phase. The soap titration method is best for determining the average particle size of a latex for purposes of predicting equilibrium swelling.

Minimum Particle Diameter of the Sulfur-Doped Nano-TiO2 Transparent Hydrosol at Room Temperature

2014 ◽  
Vol 587-589 ◽  
pp. 788-791
Author(s):  
Ling Li ◽  
Hua Yan Zhang ◽  
Xiao Wei Li ◽  
Zi Hao Xu ◽  
Sen Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Room Temperature ◽  
Photocatalytic Performance ◽  
Raw Materials ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Synthesis Process ◽  
Average Particle ◽  
Hydrolysis Method ◽  
Particle Size Analyzer

Sulfur-doped nanoTiO2transparent hydrosol with an average particle size of 3.8 nm was synthesized by a novel complexation-controlled hydrolysis method at room temperature and atmospheric pressure by using TiCl4, thiourea, organic carboxylic acid, NH3H2O, D-sorbitol etc. as raw materials. The composition, phase structure, particle size, absorbance spectrum, and photocatalytic performance of samples were characterized by XRD, nanolaser particle size analyzer, ultraviolet-visible spectrophotometer. In addition, the influence of reaction conditions in the synthesis process was also studied. The results indicate that when nanoparticle doped with 0.5% S, and the reflux time was 15 min, the photocatalytic performance of sulfur-doped TiO2hydrosol was best.

Solid State Chemical Reaction Synthesis and Characterization of Nanocrystalline Cerium Carbonate Rare Earth Compound

2014 ◽  
Vol 543-547 ◽  
pp. 3776-3780
Author(s):  
Dao Hua Li ◽  
Shao Fen He
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Size Distribution ◽  
Solid State Reaction ◽  
Particle Diameter ◽  
Average Particle ◽  
Reaction Conditions ◽  
Rare Earth Compound ◽  
Inert Substance ◽  
Cerium Carbonate

Under the conditions of the presence of surfactants and ultrasonication, the use of different cerium salt, respectively, with carbonate under solid state chemistry reactions, the synthesis of nanorare earth metal complexes of cerium carbonate crystals was formed. The solid phase was characterized by powder X-ray diffraction (XRD) and electron diffraction (ED). The particle size, its distribution, and morphology of the prepared nanocrystallite were observed by transmission electron microscopy (TEM). The results show that particle sizes are relatively uniform, the morphology of the crystal is spherical, the average particle diameter is about 60 nm, and the yield rate is approximately 93.2%. Furthermore, during the synthesis, the solid-state reaction conditions including raw materials, matching proportion of reactants, additions of inert substance, addition of trace solvents, surfactants and porphyrization time, etc, all have some influence on the morphology, particle size and size distribution of the final products. During the synthesis of the cerium carbonate nanocrystallites, the solid state reaction conditions such as changing reactant, matching proportion of reactant, adding inert substance, joining a little solvent or surface active solvent and grinding at different times may influence morphology, particle size and the size distribution of final products.

Solid-State Chemical Reaction Synthesis and Characterization of Nanocrystalline CePO4 under Ultrasonication Spectra

2012 ◽  
Vol 602-604 ◽  
pp. 153-156
Author(s):  
Dao Hua Li
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Size Distribution ◽  
Solid State Reaction ◽  
Solid Phase ◽  
Particle Diameter ◽  
Earth Metal ◽  
Average Particle ◽  
Reaction Conditions ◽  
Inert Substance

Under the conditions of the presence of surfactants and ultrasonication, the use of different cerium salt, respectively, with phosphate under solid state chemistry reactions, the synthesis of nano-rare earth metal complexes of CePO4 crystals was formed. The solid phase was characterized by powder X-ray diffraction and electron diffraction. The particle size, its distribution, and morphology of the prepared nanocrystallite were observed by transmission electron microscopy. The results show that particle sizes are relatively uniform, the morphology of the crystal is spherical, the average particle diameter is about 50 nm, and the yield rate is approximately 92.8%. Furthermore, during the synthesis, the solid-state reaction conditions including raw materials, matching proportion of reactants, additions of inert substance, addition of trace solvents, surfactants and porphyrization time, etc, all have some influence on the morphology, particle size and size distribution of the final products. During the synthesis of the nanocrystalline CePO4, the solid state reaction conditions such as changing reactant, matching proportion of reactant, adding inert substance, joining a little solvent or surface active solvent and grinding at different times may influence morphology, particle size and the size distribution of final products.

“Colloidal” Zinc Oxide

1937 ◽  
Vol 10 (2) ◽  
pp. 309-311
Author(s):  
H. A. Curran ◽  
T. R. Dawson
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Manufacturing Industry ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Average Particle ◽  
Average Particle Diameter ◽  
Zinc Oxides ◽  
Two Samples ◽  
Good Grade

Abstract Some ten years ago, when so-called “colloidal” zinc oxides were being introduced to the rubber manufacturing industry, two samples were investigated to determine their behavior in rubber compared with ordinary good quality zinc oxide used in rubber. According to accounts published at the time, “colloidal” zinc oxide possesses an average particle size just within the limit of resolution of high-power microscopes, and an average particle diameter of 0.15 micron. In rubber it has been claimed to impart superior reinforcement, higher tensile strength, greater resistance to abrasion, and enhanced activation of organic accelerators. In the following report, samples A and B represent two samples of the same grade of “colloidal” zinc oxide, and C a good grade of regular zinc oxide.

Effect of Agglomerate Powders Particle Size on Preparation of Hollow Multiphase Ceramic Microspheres by Self-Reactive Quenching Method

2013 ◽  
Vol 873 ◽  
pp. 285-291
Author(s):  
Yong Shen Hou ◽  
Jian Jiang Wang ◽  
Yong Zhao Hou ◽  
Hong Fei Lou ◽  
Hai Tao Gao
Keyword(s):  
Particle Size ◽  
Phase Composition ◽  
Particle Diameter ◽  
Fine Powder ◽  
Flame Spraying ◽  
Reactive System ◽  
Average Particle ◽  
Product Phase ◽  
High Temperature Synthesis ◽  
Quenching Method

Adopting self-reaction quenching technology based on flame spraying technique, self-propagating high-temperature synthesis and quick chilling technique, hollow multiphase ceramic microspheres are prepared. With Al+Cr2O3+Fe+Fe2O3+MnO2 as reactive system, agglomerate powders are obtained and then distinguished as thick powders and fine powders according to the different particle size. The relationship between agglomerate powders initial particle size and hollow ceramic microspheres is analyzed by the means of SEM, EDS, XRD and particle-size analyzer. The result shows that average particle diameter of thick powder is 24.49μm and that of fine powder is 17.15μm. Particle diameters of thick powder quenching product distribute within the range of 20~50μm, and those of fine powder distribute within the range of 5~30μm. The thick powder quenching product phase composition consists of Mn2AlO4,Fe2O3,Fe3O4,FeCr2O4,Cr2O3,Al2O3The fine powder quenching product phase composition consists of Mn2AlO4,Fe2O3,FeCr2O4,Fe3O4.

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