The Flocculation of Dilute Latex by Zinc Sulfate

1954 ◽  
Vol 27 (2) ◽  
pp. 481-493
Author(s):  
Pierre Thirion
Keyword(s):  
Ph Value ◽  
Systematic Investigation ◽  
Point Of View ◽  
Water Soluble ◽  
Zinc Salt ◽  
Two Samples ◽  
Initial Ph ◽  
The Stability ◽  
Necessary And Sufficient ◽  
Salt Index

Abstract Within a particular range of temperatures and a particular concentration of rubber, the flocculation of diluted latex by a water-soluble zinc salt is characterized by a critical amount of zinc, termed the salt index, which is necessary and sufficient to destroy abruptly the colloidal equilibrium of the dispersion. In the course of an investigation of a preliminary nature, measurements were made of the changes of the salt index as a function of the concentration and of the initial pH value of different field latexes and of two samples of latex preserved with ammonia. The influence of centrifugation and of buffering agents was likewise investigated. On a theoretical basis, the phenomenon appears to be governed to a major degree by chemical reactions of the zinc with certain substances which are either in solution in the serum or are adsorbed on the rubber particles. From the practical point of view, a systematic investigation is underway to determine whether the salt index as thus defined can be accepted as a new test of the stability of Fresh latex and preserved latex.

scholarly journals Anthocyanins: Factors Affecting Their Stability and Degradation

Antioxidants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1967
Author(s):  
Bianca Enaru ◽  
Georgiana Drețcanu ◽  
Teodora Daria Pop ◽  
Andreea Stǎnilǎ ◽  
Zorița Diaconeasa
Keyword(s):  
Antimicrobial Properties ◽  
Point Of View ◽  
Water Soluble ◽  
Factors Affecting ◽  
Color Palette ◽  
Number Of Factors ◽  
Major Disadvantage ◽  
Phenolic Group ◽  
The Stability ◽  
The Impact

Anthocyanins are secondary metabolites and water-soluble pigments belonging to the phenolic group, with important functions in nature such as seed dispersal, pollination and development of plant organs. In addition to these important roles in plant life, anthocyanins are also used as natural pigments in various industries, due to the color palette they can produce from red to blue and purple. In addition, recent research has reported that anthocyanins have important antioxidant, anticancer, anti-inflammatory and antimicrobial properties, which can be used in the chemoprevention of various diseases such as diabetes, obesity and even cancer. However, anthocyanins have a major disadvantage, namely their low stability. Thus, their stability is influenced by a number of factors such as pH, light, temperature, co-pigmentation, sulfites, ascorbic acid, oxygen and enzymes. As such, this review aims at summarizing the effects of these factors on the stability of anthocyanins and their degradation. From this point of view, it is very important to be precisely aware of the impact that each parameter has on the stability of anthocyanins, in order to minimize their negative action and subsequently potentiate their beneficial health effects.

scholarly journals Phenomenology of NNLO jet production at the LHC and its impact on parton distributions

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Rabah Abdul Khalek ◽  
Stefano Forte ◽  
Thomas Gehrmann ◽  
Aude Gehrmann-De Ridder ◽  
Tommaso Giani ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Systematic Investigation ◽  
Point Of View ◽  
Dijet Production ◽  
Parton Distributions ◽  
Jet Production ◽  
Before And After ◽  
Inclusive Jet ◽  
8 Tev ◽  
The Stability

Abstract We present a systematic investigation of jet production at hadron colliders from a phenomenological point of view, with the dual aim of providing a validation of theoretical calculations and guidance to future determinations of parton distributions (PDFs). We account for all available inclusive jet and dijet production measurements from ATLAS and CMS at 7 and 8 TeV by including them in a global PDF determination, and comparing to theoretical predictions at NNLO QCD supplemented by electroweak (EW) corrections. We assess the compatibility of the PDFs, specifically the gluon, obtained before and after inclusion of the jet data. We compare the single-inclusive jet and dijet observables in terms of perturbative behaviour upon inclusion of QCD and EW corrections, impact on the PDFs, and global fit quality. In the single-inclusive case, we also investigate the role played by different scale choices and the stability of the results upon changes in modelling of the correlated experimental systematics.

Preparation and Characterization of Cationic Emulsion of Styrene and Acrylate

2011 ◽  
Vol 55-57 ◽  
pp. 1886-1891
Author(s):  
Xian Mei Zhu ◽  
Gang Hu Cheng ◽  
Hong Zhao Liu
Keyword(s):  
Particle Size ◽  
Charge Density ◽  
Emulsion Polymerization ◽  
Dimethyl Sulphate ◽  
Particle Distribution ◽  
Ph Value ◽  
Reactivity Ratio ◽  
Water Soluble ◽  
Glass Temperature ◽  
The Stability

The control of particle size and its distribution has become more and more important both in theory and in practice of emulsion polymerization field. In this study, cationic styrene-acrylate copolymer containing functional monomer was converted into water-soluble polymers by reaction with quaternising agents and acids with the free-soap emulsion polymerization method. The latex was obtained at the existence of nitrogen by the copolymerization of hydrophobic monomer styrene and 2-ethylhexyl acrylate, hydrophilic monomer dimethylaminoethyl methacrylate, modified PVA-0588 as the emulsifiers. The influences of the amount of azoisobutyronitrile initiator, the amount of dimethyl sulphate quaternising agent, reactivity ratio between monomers, charge density and pH value on the preparation process were discussed. The particle size and particle distribution was strongly affected by these factors. The results showed that the latex with narrow particle distribution and mean particle size about 100nm was obtained under redox system by adjusting 33% monomer to become precursor and dropping the rest of 67% monomer, after polymerization, N,N-dimethylamino groups were fully quaternised with dimethyl sulphate to improve the stability of the solutions. The glass temperature of polymer was 58.1°C, as pH values range of solution was 3~5, the stability and charge density of polymer emulsion could improve.

scholarly journals Characteristics and kinetic analysis of β-glucosidase (MaBgl) from Mucor ardhlaengiktus RSC1

BioResources ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 1626-1638
Author(s):  
Zhihai Yang ◽  
Liping Wu ◽  
Mingjia Fu ◽  
Qin Li ◽  
Dexiao Ye
Keyword(s):  
Thermal Stability ◽  
Ph Value ◽  
Fermentation Broth ◽  
Hydrolytic Enzymes ◽  
Maximum Velocity ◽  
Exchange Chromatography ◽  
Cellulolytic Enzymes ◽  
Good Thermal Stability ◽  
Initial Ph ◽  
The Stability

Cellulolytic enzymes from fungi are complex compound enzyme structures that generally include three kinds of hydrolytic enzymes, which are called endo-β-1,4-glucanases, exo-β-1,4-glucanases, and β-1,4-glucosidases (β-glucosidases). The fungus Mucor ardhlaengiktus isolated from field rice straw produced a β-glucosidase (MaBgl). Maximal MaBgl production occurred when M. ardhlaengiktus was incubated for 6 days in fermentation liquor at 30 °C and an initial pH of 6. Purified MaBgl was obtained from M. ardhlaengiktus fermentation broth by ammonium sulfate fractional precipitation and DEAE-Sepharose FF ion exchange chromatography. The molecular weight of MaBgl as determined by SDS-PAGE electrophoresis was approximately 72 kDa. The kinetic parameters, Michaelis constant (Km) and maximum velocity (Vmax), of MaBgl were 78.2 μmol/L and 28.5 μmol/(L·min), respectively. Assays of MaBgl produced by M. ardhlaengiktus RSC1 under different conditions were investigated by the 3,5-dinitrosalicylic acid (DNS) assay for glucose. The pH and temperature optima for catalytic activity of MaBgl were pH 4.8 and 50 °C, respectively. MaBgl exhibited good thermal stability in the range of 20 to 30 °C, but the thermal stability of MaBgl decreased rapidly over 60 °C. MaBgl had better pH stability between pH 4.6 and 5.0, and the stability of MaBgl decreased when the pH value was lower or higher than this range.

Stability of vitamins during the storage of liquid infant milks

2000 ◽  
Vol 67 (2) ◽  
pp. 225-231 ◽  
Author(s):  
SOLEDAD ALBALÁ-HURTADO ◽  
M. TERESA VECIANA-NOGUÉS ◽  
ENRIQUE RIERA-VALLS ◽  
ABEL MARINÉ-FONT ◽  
M. CARMEN VIDAL-CAROU
Keyword(s):  
Kinetic Equation ◽  
Vitamin A ◽  
Storage Temperature ◽  
Storage Period ◽  
Water Soluble ◽  
The Other ◽  
Two Samples ◽  
The Stability ◽  
Fat Soluble Vitamins ◽  
Storage Temperatures

The stability of the water-soluble B vitamins and the fat-soluble vitamins A and E of three liquid infant milks was followed throughout 12 months of storage at 20, 30 and 37 °C. Two samples were ‘follow-on’ milks from two different manufacturers and the other a ‘junior’ milk from one of these. The levels of water-soluble vitamins and vitamin E remained constant during storage at the three temperatures. In contrast, vitamin A decreased in samples from one manufacturer at all storage temperatures, and in samples from the other only at 37 °C. A kinetic equation was derived that made it possible to predict the influence of storage temperature on the shelf life of these kinds of products, together with the storage period during which levels of vitamin A recommended as adequate would remain.

Analysis of Clinical Stability of Ophthalmic Preparations Combined with Artificial Intelligence Medical Image Technology

2021 ◽  
Vol 11 (1) ◽  
pp. 120-126
Author(s):  
Tangtang Jin ◽  
Gangze Fu ◽  
Lina Ge ◽  
Peizhen Lin
Keyword(s):  
Artificial Intelligence ◽  
Polyethylene Glycol ◽  
High Temperature ◽  
Medical Image ◽  
Ph Value ◽  
High Light ◽  
Initial Value ◽  
Environment Temperature ◽  
Initial Ph ◽  
The Stability

This study aims to analyze the stability of ophthalmic reagent cyclosporine polypeptide A and provide theoretical basis for future clinical medication. In this study, polyethylene glycol stearate with good physiological tolerance was selected to replace the emulsifier Tween80 in the sell prescription. The sell prescription was set as reagent 1, and the improved reagent was set as reagent 2. The two reagents were placed under high temperature (45 °C and 65 °C) and high light (4600Ix) for 18 days, and the pH and content of the two reagents were detected and recorded by artificial intelligence (AI) medical image segmentation technology based on Gabor wavelet function at 6 days, 12 days, and 18 days. Then, considering the actual storage problem of the reagent, the two reagents were placed in an environment (temperature of about 25 °C, relative humidity of about 60%, and protection from light) for 24 months. The pH and content of the two reagents were detected and recorded by hyperspectral images at 8, 16, and 24 months. The results showed that the pH value and content of the two reagents did not change significantly over time at 45 °C (P > 0.05), and the pH and content of reagent 1 after 6 days at 65 °C were significantly less than the initial pH value (P < 0.05). The pH and content of reagent 2 after 12 days were significantly lower than the initial pH value (P < 0.05). Under strong illumination, the pH value and content of reagent 1 decreased with time, and there were significant differences (P < 0.05). The pH value of reagent 2 showed no significant difference between 0 and 18 days (P > 0.05), and the content was significantly lower than the initial content after 12 days of placement (P < 0.05). The pH value and content of reagent 1 were significantly lower than the initial value after 16 months of storage (P < 0.05). And the pH value and content of reagent 2 were significantly lower than the initial value when stored for 24 months (P < 0.05). It showed that ophthalmic reagent cyclosporine polypeptide A is sensitive to high temperature and high light, and should avoid light and cool down during the transportation in hot season. Therefore, the adoption of polyethylene glycol stearate can effectively improve the stability of ophthalmic reagent cyclosporine polypeptide A, which has a high value in clinical application.

Framework Fe-Doped Mobil Five (MFI) Zeolites as Highly Active and Stable Fenton-Like Catalysts for Basic Dyes Degradation

2020 ◽  
Vol 20 (3) ◽  
pp. 1520-1529 ◽  
Author(s):  
Senlin Deng ◽  
Guojun Lv ◽  
Yi Zhai ◽  
Zebin Yang ◽  
Yongqiang Zhu ◽  
...  
Keyword(s):  
Ph Value ◽  
Operational Parameters ◽  
One Pot ◽  
Highly Active ◽  
Fe Content ◽  
Basic Dyes ◽  
Initial Ph ◽  
Ft Ir ◽  
The Stability ◽  
Mfi Zeolites

Highly active and stable framework Fe-doped ZSM-5 (f-Fe-ZSM-5) zeolites with different Fe contents, which were synthesized using a facile one-pot hydrothermal method, could effectively resolve the loss of iron element during the catalytic degradation of basic dyes. The successful introduction of Fe species into the framework of ZSM-5 was confirmed by elemental mappings, Fourier transform infrared (FT-IR) spectroscopy and Ultraviolet-visible spectroscopy (UV-vis spectra). The operational parameters, such as Fe content, H2O2 concentration, reaction temperature, types of dyes as well as the stability of the synthesized samples were extensively evaluated. It was demonstrated that the f-Fe(0.10)-ZSM-5 exhibited an efficient catalytic ability and excellent stability even after seven consecutive runs. The degradation efficiency of f-Fe-ZSM-5 for basic dyes was higher than that for acid dye. Therefore, f-Fe-ZSM-5 zeolites may present major potential for the treatment of basic dyes waste water without adjusting the initial pH value.

scholarly journals Photocatalytic Degradation of a Water Soluble Herbicide by Pure and Noble Metal DepositedTiO2Nanocrystalline Films

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
Katerina Pelentridou ◽  
Elias Stathatos ◽  
Helen Karasali ◽  
Dionysios D. Dionysiou ◽  
Panagiotis Lianos
Keyword(s):  
Photocatalytic Degradation ◽  
Noble Metals ◽  
Ph Value ◽  
Water Soluble ◽  
Alkaline Media ◽  
Nanocrystalline Films ◽  
First Order Kinetics ◽  
Photodegradation Rate ◽  
Valence States ◽  
Initial Ph

We present the photocatalytic degradation of a water soluble sulfonylurea herbicide: azimsulfuron in the presence of titania nanocrystalline films. Efficient photodegradation of herbicide was achieved by using low-intensity black light tubes emitting in the Near-UV. The degradation of the herbicide follows first-order kinetics according to the Langmuir-Hinshelwood model. Intermediate products were identified by the LC-MS-MS technique during photocatalytic degradation. In order to increase photodegradation rate of the herbicide, we examined the effect of titania modification by depositing noble metals at various quantities and valence states. The presence of platinum at neutral valence state and optimum concentration induced higher photodegradation rates while silver-modified titania exhibited similar photocatalytic rates with those obtained with pure nanocrystallineTiO2films. Finally, the effect of initial pH value was also examined. Acidic or alkaline media were unfavorable for azimsulfuron photodegradation.

Sorbitol enhances the physicochemical stability of B12 vitamers

2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot
Keyword(s):  
Ascorbic Acid ◽  
Uv Light ◽  
Heat Exposure ◽  
Water Soluble ◽  
Uv Exposure ◽  
Physicochemical Stability ◽  
Before And After ◽  
The Stability

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

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.

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