Leaching behavior and chemical stability of copper butyl xanthate complex under acidic conditions

Chemosphere ◽  
2003 ◽  
Vol 52 (6) ◽  
pp. 1089-1094 ◽  
Author(s):  
Yi-Kuo Chang ◽  
Juu-En Chang ◽  
Li-Choung Chiang
Keyword(s):  
Chemical Stability ◽  
Butyl Xanthate ◽  
Leaching Behavior ◽  
Acidic Conditions

Characterization of lead-bearing phases in municipal waste combustor fly ash

1996 ◽  
Vol 54 ◽  
pp. 516-517
Author(s):  
L. L. Sutter ◽  
G. R. Dewey ◽  
J. F. Sandell
Keyword(s):  
Fly Ash ◽  
Bottom Ash ◽  
Municipal Waste ◽  
Primary Concern ◽  
Leaching Behavior ◽  
Waste Combustion ◽  
Lead And Cadmium ◽  
Lead Speciation ◽  
Accepted Practice

Municipal waste combustion typically involves both energy recovery as well as volume reduction of municipal solid waste prior to landfilling. However, due to environmental concerns, municipal waste combustion (MWC) has not been a widely accepted practice. A primary concern is the leaching behavior of MWC ash when it is stored in a landfill. The ash consists of a finely divided fly ash fraction (10% by volume) and a coarser bottom ash (90% by volume). Typically, MWC fly ash fails tests used to evaluate leaching behavior due to high amounts of soluble lead and cadmium species. The focus of this study was to identify specific lead bearing phases in MWC fly ash. Detailed information regarding lead speciation is necessary to completely understand the leaching behavior of MWC ash.

Nε-Acetyl L-α Lysine Improves Activity and Stability of α-Amylase at Acidic Conditions: A Comparative Study with other Osmolytes

2020 ◽  
Vol 27 (6) ◽  
pp. 551-556
Author(s):  
Nidhya N. Joghee ◽  
Gurunathan Jayaraman ◽  
Masilamani Selladurai
Keyword(s):  
Enzyme Activity ◽  
Amino Acid ◽  
Thermodynamic Stability ◽  
Protective Effects ◽  
Residual Enzyme Activity ◽  
Functional Stability ◽  
Biotechnological Applications ◽  
Optimal Temperature ◽  
Acidic Conditions ◽  
Cellular Components

Background: Nε-acetyl L-α lysine is an unusual acetylated di-amino acid synthesized and accumulated by certain halophiles under osmotic stress. Osmolytes are generally known to protect proteins and other cellular components under various stress conditions. Objective: The structural and functional stability imparted by Nε-acetyl L-lysine on proteins were unknown and hence was studied and compared to other commonly known bacterial osmolytes - ectoine, proline, glycine betaine, trehalose and sucrose. Methods: Effects of osmolytes on the temperature and pH profiles, pH stability and thermodynamic stability of the model enzyme, α-amylase were analyzed. Results: At physiological pH, all the osmolytes under study increased the optimal temperature for enzyme activity and improved the thermodynamic stability of the enzyme. At acidic conditions (pH 3.0), Nε-acetyl L-α lysine and ectoine improved both the catalytic and thermodynamic stability of the enzyme; it was reflected in the increase in residual enzyme activity after incubation of the enzyme at pH 3.0 for 15 min by 60% and 63.5% and the midpoint temperature of unfolding transition by 11°C and 10°C respectively. Conclusion: Such significant protective effects on both activity and stability of α-amylase imparted by addition of Nε-acetyl L-α lysine and ectoine at acidic conditions make these osmolytes interesting candidates for biotechnological applications.

Preparation of Organized Mesoporous Silica from Sodium Metasilicate Solutions in Alkaline Medium Using Nonionic Surfactants

2003 ◽  
Vol 68 (10) ◽  
pp. 2019-2031 ◽  
Author(s):  
Markéta Zukalová ◽  
Jiří Rathouský ◽  
Arnošt Zukal
Keyword(s):  
Mesoporous Silica ◽  
Ethylene Oxide ◽  
Sodium Metasilicate ◽  
Spherical Particles ◽  
Structure Directing Agent ◽  
Inorganic Species ◽  
Poly Ethylene Oxide ◽  
Acidic Conditions ◽  
Poly Ethylene ◽  
Hydrolysis Of

A new procedure has been developed, which is based on homogeneous precipitation of organized mesoporous silica from an aqueous solution of sodium metasilicate and a nonionic poly(ethylene oxide) surfactant serving as a structure-directing agent. The decrease in pH, which induces the polycondensation of silica, is achieved by hydrolysis of ethyl acetate. Owing to the complexation of Na+ cations by poly(ethylene oxide) segments, assembling of the mesostructure appears to occur under electrostatic control by the S0Na+I- pathway, where S0 and I- are surfactant and inorganic species, respectively. As the complexation of Na+ cations causes extended conformation of poly(ethylene oxide) segments, the pore size and pore volume of organized mesoporous silica increase in comparison with materials prepared under neutral or acidic conditions. The assembling of particles can be fully separated from their solidification, which results in the formation of highly regular spherical particles of mesoporous silica.

scholarly journals An investigation of the effect of Zataria multiflora Boiss and Mentha piperita essential oils to improve the chemical stability of minced meat

2018 ◽  
pp. 1656-1662 ◽  
Author(s):  
Mojtaba Raeisi ◽  
Mohammad Hashemi ◽  
Majid Aminzare ◽  
Asma Afshari ◽  
Tayebeh Zeinali ◽  
...  
Keyword(s):  
Treatment Group ◽  
Essential Oils ◽  
Chemical Stability ◽  
Radical Scavenging ◽  
Antioxidant Potential ◽  
Mentha Piperita ◽  
Total Phenolic ◽  
Control Group ◽  
Zataria Multiflora ◽  
Minced Meat

Background and Aim: Extending the shelf life of foods is an essential concept in food safety. Most of the time, foods deteriorate through the growth of microorganisms or oxidation process. Essential oils (EOs) derived from plant material have well-documented antioxidant and antibacterial activity. This study aimed to evaluate the effect of Zataria multiflora Boiss EO (ZEO) and Mentha piperita EO (MEO) on the chemical stability of minced meat during storage at 7°C. Materials and Methods: Total phenolic content, β-Carotene bleaching test, ferric reducing antioxidant potential assay, and 2,2-Diphenyl-1-picrylhydrazyl radical scavenging activity were used to determine the antioxidant potential of EOs. Five different groups including control, ZEO 0.3%, ZEO 0.5%, MEO 0.3%, and MEO 0.5% were designed to assess the chemical stability of minced meat by measuring pH, thiobarbituric acid (TBA), total volatile base nitrogen (TVBN), and peroxide value (PV). Results: pH did not have any significant change during storage. TBA values in the control group were significantly higher than the treatment groups, especially from the 5th day of storage. TVBN in the treatment group was significantly lower than the control group during storage. PV values in the treatment group were significantly lower than the control group during storage. Conclusion: Results indicate that ZEO and MEO had an excellent antioxidant activity and retarded the spoilage process in minced meat. Keywords: antioxidant, Mentha piperita, minced meat, Zataria multiflora Boiss.

A matrix targeted fluorescent probe to monitor mitochondrial dynamics

2021 ◽  
Author(s):  
Madhu Ramesh ◽  
Kolla Rajasekhar ◽  
Kavya Gupta ◽  
Vardhaman Babagond ◽  
Deepak Kumar Saini ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Chemical Stability ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Matrix ◽  
Turn On

A far-red turn-on fluorescent probe (Mito-TG) with excellent biocompatibility, photostability, chemical stability targets mitochondrial matrix. The insensitivity of probe under different pH and ROS enabled tracking of mitophagy and Aβ induced mitochondrial dynamics.

scholarly journals The Hsp60 Protein of Helicobacter Pylori Exhibits Chaperone and ATPase Activities at Elevated Temperatures

BioChem ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 19-25
Author(s):  
Jose A. Mendoza ◽  
Julian L. Ignacio ◽  
Christopher M. Buckley
Keyword(s):  
Helicobacter Pylori ◽  
Heat Stress ◽  
Molecular Chaperone ◽  
Elevated Temperatures ◽  
Citrate Synthase ◽  
Gastric Epithelium ◽  
Acidic Conditions ◽  
H Pylori ◽  
Induced Aggregation ◽  
Hydrolysis Of

The heat-shock protein, Hsp60, is one of the most abundant proteins in Helicobacter pylori. Given its sequence homology to the Escherichia coli Hsp60 or GroEL, Hsp60 from H. pylori would be expected to function as a molecular chaperone in this organism. H. pylori is a type of bacteria that grows on the gastric epithelium, where the pH can fluctuate between neutral and 4.5, and the intracellular pH can be as low as 5.0. We previously showed that Hsp60 functions as a chaperone under acidic conditions. However, no reports have been made on the ability of Hsp60 to function as a molecular chaperone under other stressful conditions, such as heat stress or elevated temperatures. We report here that Hsp60 could suppress the heat-induced aggregation of the enzymes rhodanese, malate dehydrogenase, citrate synthase, and lactate dehydrogenase. Moreover, Hsp60 was found to have a potassium and magnesium-dependent ATPase activity that was stimulated at elevated temperatures. Although, Hsp60 was found to bind GTP, the hydrolysis of this nucleotide could not be observed. Our results show that Hsp60 from H. pylori can function as a molecular chaperone under conditions of heat stress.

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