Effect of pH Value of the Broth on the Gelled Microspheres Containing Zirconium Prepared by Internal Gelation Process

2014 ◽  
Vol 602-603 ◽  
pp. 155-158 ◽  
Author(s):  
Yong Gao ◽  
Jing Tao Ma ◽  
Xing Yu Zhao ◽  
Shao Chang Hao ◽  
Chang Sheng Deng
Keyword(s):  
Room Temperature ◽  
Ph Value ◽  
Internal Gelation ◽  
Uniform Size ◽  
Effect Of Ph ◽  
Gelation Process ◽  
The Stability

The internal gelation process was used to produce gel microspheres containing Zr. The effect of the broth composition particularly pH value on the stability of the broth and morphology of the dried spheres was investigated. The results indicated that the stability of the broth at room temperature increased with the decrease of the pH of the broth. When the pH of the broth was in the range of 1 to 2 the spheres obtained had good sphericity and uniform size and at pH of 1.35 the spheres were transparent.

Effect of Ammonia on CeO2 Microspheres Prepared by Internal Gelation Process

2018 ◽  
Vol 281 ◽  
pp. 9-14
Author(s):  
Xue Qiang Ding ◽  
Jing Tao Ma ◽  
Xing Yu Zhao ◽  
Shao Chang Hao ◽  
Chang Sheng Deng ◽  
...  
Keyword(s):  
Grain Size ◽  
Surface Morphology ◽  
Cerium Dioxide ◽  
Smooth Surface ◽  
Molar Ratio ◽  
Internal Gelation ◽  
Compact Structure ◽  
Gelation Process ◽  
The Stability

The internal gelation process was used to prepare cerium dioxide microspheres. The effect of ammonia on the stability of the precursor solutions was investigated with the NH3∙H2O/Ce (NH4)2(NO3)6 molar ratio from 0 to 1.25. The surface morphology and microstructure of the sintered CeO2 microspheres were analyzed. With the increase of NH3∙H2O/Ce (NH4)2(NO3)6 molar ratio, the solutions became more unstable, which indicated that their gelation was initiated. When the NH3∙H2O/Ce (NH4)2(NO3)6 ratio varied from 0 to 0.75, the surface of the microspheres became rougher and grain size became larger. Further increase in the NH3∙H2O/Ce (NH4)2(NO3)6 ratios to 1 and 1.25 led to CeO2 microspheres with smooth surface and compact structure.

The Formation of Alumina Ceramic Microspheres by Internal Gelation Process

2015 ◽  
Vol 655 ◽  
pp. 103-107 ◽  
Author(s):  
Yong Gao ◽  
Jing Tao Ma ◽  
Xing Yu Zhao ◽  
Shao Chang Hao ◽  
Chang Sheng Deng
Keyword(s):  
Silicone Oil ◽  
Average Diameter ◽  
Alumina Ceramic ◽  
Internal Gelation ◽  
Uniform Size ◽  
Gelation Process ◽  
Crush Strength

Alumina ceramic microspheres were prepared via internal gelation process. By dropping sol from a cold broth into hot silicone oil gelled microspheres would solidify within a few seconds by decomposition of hexamethylenetetramine (HMTA). The effect of the broth component on the performance of the broth and gelled microspheres obtained has been investigated. The Al2O3 ceramic microspheres can be obtained after aging, washing, drying and sintering. The Al2O3 microspheres prepared with optimized formulation have uniform size and good sphericity, with an average diameter of 690μm and crush strength of greater than 12N/sphere.

Enhancing the Stability of Asphalt Emulsion Using Environmentally Friendly Cationically Modified Hydroxyethyl Cellulose (CMHEC) at Different Concentrations and pH Values

2021 ◽  
Vol 58 (4) ◽  
pp. 303-310
Author(s):  
Xiaoxi Wang ◽  
Runhan Hou ◽  
Qian Zhang ◽  
Osama M. Darwesh ◽  
Mengyao Gao ◽  
...  
Keyword(s):  
Phase Separation ◽  
Apparent Viscosity ◽  
Ph Value ◽  
Ph Effect ◽  
Environmentally Friendly ◽  
Hydroxyethyl Cellulose ◽  
Asphalt Emulsion ◽  
Effect Of Ph ◽  
Ph Values ◽  
The Stability

Abstract The cationically modified hydroxyethyl cellulose (CMHEC) was synthesized successfully and applied for preparing the cationic asphalt emulsion. The apparent viscosity and phase separation of the emulsion were studied at different CMHEC concentrations and pH values. The results indicated that the apparent viscosity of the emulsion was increased with increasing CMHEC concentration, and the phase separation was significantly reduced correspondingly. In addition, the effect of pH value on the emulsion quality was involved. The apparent viscosity of the emulsion showed the tendency to decrease firstly and then increase to the minimum value at pH 2. All results indicated that CMHEC has excellent potential in the manufacture of asphalt emulsion and the research of the pH effect on the formulation of asphalt emulsion has essential significance.

scholarly journals The Size Stability of Alginate Beads by Different Ionic Crosslinkers

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Shu-Ling Huang ◽  
Yung-Sheng Lin
Keyword(s):  
Low Temperature ◽  
Room Temperature ◽  
Alginate Bead ◽  
Alginate Beads ◽  
Size Reduction ◽  
Ionic Gelation ◽  
Gelation Process ◽  
Size Stability ◽  
The Stability ◽  
Gelling Time

Few studies have discussed the stability of gelled alginate bead size. Therefore, the present study investigated the dynamic shrinkage of gelled alginate beads affected by two common ionic crosslinkers at different concentrations and temperatures. The results indicate that the gelled alginate beads gradually shrank with longer gelling times. The beads incubated in a Ca2+ solution shrank more dramatically than those incubated in a Ba2+ solution. Those incubated at room temperature exhibited greater shrinkage than those incubated at a low temperature. A 25% size reduction occurred in the 1% Ca2+ solution at room temperature after 300 minutes of gelling time. The alginate beads gelled took at least 120 minutes to become stable after the ionic gelation process.

scholarly journals Size- and Surface-Dependent Solubility of Cadmium Telluride in Aqueous Solutions

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 398 ◽  
Author(s):  
Renate Zapf-Gottwick ◽  
Matthias Zorn ◽  
Jessica Nover ◽  
Michael Koch ◽  
Carolin Feifel ◽  
...  
Keyword(s):  
Particle Size ◽  
Aqueous Solutions ◽  
Diffusion Coefficients ◽  
Room Temperature ◽  
Ph Value ◽  
Leaching Behavior ◽  
Photovoltaic Modules ◽  
Chemical Treatments ◽  
Temperature Diffusion ◽  
The Stability

Due to the toxicity of cadmium (Cd) and the scarcity of telluride (Te), CdTe-based photovoltaic modules have been under discussion during the last few years. In particular, the stability of CdTe in aqueous solutions is under debate. Here we show that the stability of CdTe depends not only on the pH of water-based solutions but also on size and surface treatment of CdTe particles. We compare milled module pieces with CdTe powders of different particle size. The leaching of CdTe is conditioned by the outdiffusion of Cd and Te at the interface between CdTe particles and the aqueous solution. The smaller the particle size, the faster the leaching. Therefore, milled module pieces decompose faster than CdTe powders with relatively large grains. We observe a dependence on time t according to t0.43. The room temperature diffusion coefficients are calculated as DCd ≈ 3 × 10−17 cm2/s for Cd, and DTe ≈ 1.5 × 10−17 cm2/s for Te in pH4. The chemical instability in aqueous solutions follows thermodynamic considerations. The solution behavior of Cd and Te depends on the pH value and the redox potential of the aqueous solutions. Chemical treatments such as those used in solar cell production modify the surface of the CdTe particles and their leaching behavior.

Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

Methods for the Concentration of Bovine Ac-Globulin (Factor V)

1961 ◽  
Vol 06 (03) ◽  
pp. 435-444 ◽  
Author(s):  
Ricardo H. Landaburu ◽  
Walter H. Seegers
Keyword(s):  
Room Temperature ◽  
Barium Carbonate ◽  
Deae Cellulose ◽  
Reducing Agents ◽  
Factor V ◽  
Isoelectric Precipitation ◽  
Stabilizing Agent ◽  
Bovine Plasma ◽  
The Stability

SummaryAn attempt was made to obtain Ac-globulin from bovine plasma. The concentrates contain mostly protein, and phosphorus is also present. The stability characteristics vary from one preparation to another, but in general there was no loss before 1 month in a deep freeze or before 1 week in an icebox, or before 5 hours at room temperature. Reducing agents destroy the activity rapidly. S-acetylmercaptosuccinic anhydride is an effective stabilizing agent. Greatest stability was at pH 6.0.In the purification bovine plasma is adsorbed with barium carbonate and diluted 6-fold with water. Protein is removed at pH 6.0 and the Ac-globulin is precipitated at pH 5.0. Rivanol and alcohol fractionation is followed by chromatography on Amberlite IRC-50 or DEAE-cellulose. The final product is obtained by isoelectric precipitation.

Tyrosine-Selective Bioconjugation with Iminoxyl Radicals

2020 ◽  
Author(s):  
Katsuya Maruyama ◽  
Takashi Ishiyama ◽  
Yohei Seki ◽  
Kounosuke Oisaki ◽  
Motomu Kanai
Keyword(s):  
Reaction Time ◽  
Steric Hindrance ◽  
Room Temperature ◽  
Water Soluble ◽  
Light Irradiation ◽  
Sodium Ascorbate ◽  
Iminoxyl Radical ◽  
Short Reaction Time ◽  
Modified Peptides ◽  
The Stability

A novel Tyr-selective protein bioconjugation using the water-soluble persistent iminoxyl radical is described. The conjugation proceeded with high Tyr-selectivity and short reaction time under biocompatible conditions (room temperature in buffered media under air). The stability of the conjugates was tunable depending on the steric hindrance of iminoxyl. The presence of sodium ascorbate and/or light irradiation promoted traceless deconjugation, restoring the native Tyr structure. The method is applied to the synthesis of a protein-dye conjugate and further derivatization to azobenzene-modified peptides.

Circular dichroism and infrared study of β-turn formation in repeat peptides of elastin

1987 ◽  
Vol 52 (5) ◽  
pp. 1356-1361
Author(s):  
S. Abdel Rahman ◽  
M. Elsafty ◽  
A. Hattaba
Keyword(s):  
Circular Dichroism ◽  
Solid State ◽  
Ir Spectra ◽  
Chain Length ◽  
Room Temperature ◽  
Infrared Study ◽  
Feature Characteristic ◽  
C 50 ◽  
The Stability ◽  
Circular Dichroïsm

The conformation of elastin-like peptides Boc-Ala-Pro-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM were examined in solution using circular dichroism at 30 °C, 50 °C, and 70 °C and in solid state by IR at room temperature. The studies show that the β-turn is a significant conformational feature for peptides under investigation in solution at 30 °C and 50 °C, but at 70 °C the tetra, hexa, and decapeptides show the CD feature characteristic of the β-structure while the dodecapeptide spectra show the presence of β-turn which indicates the stability of the β-turn at this chain length. The IR spectra show that in the solid state at room temperature all investigated peptides assume essentially a β-turn except the tetrapeptide which present evidence of antiparallel β-structure. The β-turn contribution in the IR spectra increases with the increase of the chain length of the peptide.

Cholesterol in Serum and Lipoprotein Fractions

1956 ◽  
Vol 2 (3) ◽  
pp. 145-159 ◽  
Author(s):  
Joseph T Anderson ◽  
Ancel Keys
Keyword(s):  
Human Serum ◽  
Total Cholesterol ◽  
Filter Paper ◽  
Room Temperature ◽  
Paper Electrophoresis ◽  
Cholesterol Content ◽  
Intraindividual Variability ◽  
Detailed Data ◽  
The Stability ◽  
Source Of Error

Abstract 1. Methods are described for the separation, by paper electrophoresis and by cold ethanol, of α- and β-lipoproteins in 0.1 ml. of serum, with subsequent analysis of cholesterol in the separated portions. 2. It is shown that both methods of separation yield separated fractions containing substantially the same amounts of cholesterol. 3. Detailed data are given on the errors of measurement for total cholesterol and for cholesterol in the separated lipoprotein fractions. 4. Studies are reported on the stability of cholesterol in stored serum and on paper electrophoresis strips. It is shown that simple drying on filter paper causes no change in cholesterol content and yields a product that is stable for many weeks at ordinary room temperature. 5. The sources of variability in human serum cholesterol values are examined and it is shown that spontaneous intraindividual variability is a much greater source of error than the errors of measurement with these methods.

Sign in / Sign up

Export Citation Format

Share Document