Chemical Mechanisms in two Photochemical Modelling Systems: A Comparison Procedure

2004 ◽  
pp. 87-96
Author(s):  
Joana Ferreira ◽  
Anabela Carvalho ◽  
Ana C. Carvalho ◽  
Alexandra Monteiro ◽  
Helena Martins ◽  
...  
Keyword(s):  
Chemical Mechanisms ◽  
Photochemical Modelling

Chemical mechanisms of tungsten CVD

1999 ◽  
Vol 09 (PR8) ◽  
pp. Pr8-245-Pr8-250
Author(s):  
Yu. V. Lakhotkin
Keyword(s):  
Chemical Mechanisms

scholarly journals Allysine and α-Aminoadipic Acid as Markers of the Glyco-Oxidative Damage to Human Serum Albumin under Pathological Glucose Concentrations

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 474 ◽  
Author(s):  
Carolina Luna ◽  
Alexis Arjona ◽  
Carmen Dueñas ◽  
Mario Estevez
Keyword(s):  
Oxidative Stress ◽  
Plasma Concentration ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Typical Feature ◽  
Advanced Glycation ◽  
Chemical Mechanisms ◽  
Fasting Plasma ◽  
Insight Into

Understanding the molecular basis of the disease is of the utmost scientific interest as it contributes to the development of targeted strategies of prevention, diagnosis, and therapy. Protein carbonylation is a typical feature of glyco-oxidative stress and takes place in health disorders such as diabetes. Allysine as well as its oxidation product, the α-amino adipic acid (α-AA) have been found to be markers of diabetes risk whereas little is known about the chemistry involved in its formation under hyperglycemic conditions. To provide insight into this issue, human serum albumin was incubated in the presence of FeCl3 (25 μM) and increasing glucose concentrations for 32 h at 37 °C. These concentrations were selected to simulate (i) physiological fasting plasma concentration (4 mM), (ii) pathological pre-diabetes fasting plasma concentration (8 mM), and pathological diabetes fasting plasma concentration (12 mM) of glucose. While both allysine and α-AA were found to increase with increasing glucose concentrations, the carboxylic acid was only detected at pathological glucose concentrations and appeared to be a more reliable indicator of glyco-oxidative stress. The underlying chemical mechanisms of lysine glycation as well as of the depletion of tryptophan and formation of fluorescent and colored advanced glycation products are discussed.

scholarly journals Computational Catalysis—Trends and Outlook

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 479
Author(s):  
Christoffer Heath Turner
Keyword(s):  
Active Sites ◽  
Chemical Mechanisms ◽  
Research Fields ◽  
Dynamic Research ◽  
Computational Catalysis

Computational catalysis has been one of the most dynamic research fields over the last decade, and it now represents a critical tool for the analysis of chemical mechanisms and active sites [...]

Activators in Accelerated Sulfur Vulcanization

2004 ◽  
Vol 77 (3) ◽  
pp. 512-541 ◽  
Author(s):  
Geert Heideman ◽  
Rabin N. Datta ◽  
Jacques W. M. Noordermeer ◽  
Ben van Baarle
Keyword(s):  
Reaction Mechanisms ◽  
Model Compound ◽  
Background Information ◽  
Zinc Compounds ◽  
Chemical Mechanisms ◽  
Sulfur Vulcanization ◽  
Multifunctional Additives ◽  
Vulcanization Process

Abstract This review provides relevant background information about the vulcanization process, as well as the chemistry of thiuram- and sulfenamide-accelerated sulfur vulcanization with emphasis on the role of activators, to lay a base for further research. It commences with an introduction of sulfur vulcanization and a summary of the reaction mechanisms as described in literature, followed by the role of activators, particularly ZnO. The various possibilities to reduce ZnO levels in rubber compounding, that have been proposed in literature, are reviewed. A totally different approach to reduce ZnO is described in the paragraphs about the various possible roles of multifunctional additives (MFA) in rubber vulcanization. Another paragraph is dedicated to the role of amines in rubber vulcanization, in order to provide some insight in the underlying chemical mechanisms of MFA systems. Furthermore, an overview of Model Compound Vulcanization (MCV) with respect to different models and activator/accelerator systems is given. In the last part of this review, the various functions of ZnO in rubber are summarized. It clearly reveals that the role of ZnO and zinc compounds is very complex and still deserves further clarification.

A Systematic Review on Airbag-Induced Burns

2020 ◽  
Author(s):  
Sarah P Erpenbeck ◽  
Eva Roy ◽  
Jenny A Ziembicki ◽  
Francesco M Egro
Keyword(s):  
Systematic Review ◽  
Case Reports ◽  
Good Prognosis ◽  
Chemical Burns ◽  
Automobile Crashes ◽  
Chemical Mechanisms ◽  
Number Of Patients ◽  
Common Risk Factors ◽  
The Common ◽  
Ocular Burns

Abstract Airbags significantly reduce fatalities and injuries in automobile crashes, but they have been found to be associated with burns. Specifically, airbags can cause burns through thermal or chemical mechanisms and commonly affect the arms, hands, face, and eyes. While most airbag-induced burns are minor, some may cause unfavorable outcomes. Our study aimed to systematically review airbag-induced burns to assess etiology, type, and treatment of these injuries. A systematic review of case reports pertaining to airbag-induced cutaneous and ocular burns was conducted. Data reviewed included type/location of burns, severity of burn, total number of patients, treatment, complications, and outcome after treatment. We identified 21 case reports that met our inclusion criteria with a total of 24 patients reported in the studies. Of the studies identified, 38% were chemical burns and 25% were thermal burns. Most commonly the upper extremities were burned in 42% of cases, followed by eyes (25%) and face (21%). Most burns identified were superficial partial thickness (58%). Treatment outcomes were good for cutaneous burns, with 95% healing without complication. However, ocular injuries lead to permanent impaired eye function in 71% of cases. In our systematic review, we highlighted the common risk factors, prognosis, and treatment for thermal, chemical, and ocular burns. Airbag-induced burns have a relatively good prognosis but must be recognized and treated immediately to reduce the risk of serious sequelae.

scholarly journals Changes in Optical Properties upon Dye–Clay Interaction: Experimental Evaluation and Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 197
Author(s):  
Giorgia Giovannini ◽  
René M. Rossi ◽  
Luciano F. Boesel
Keyword(s):  
Optical Properties ◽  
Hybrid Materials ◽  
High Performance ◽  
Fluorescent Properties ◽  
Chemical Mechanisms ◽  
Strong Electrostatic Interaction ◽  
Potential Applications ◽  
Photochemical Properties ◽  
Physical And Chemical ◽  
The Relationship

The development of hybrid materials with unique optical properties has been a challenge for the creation of high-performance composites. The improved photophysical and photochemical properties observed when fluorophores interact with clay minerals, as well as the accessibility and easy handling of such natural materials, make these nanocomposites attractive for designing novel optical hybrid materials. Here, we present a method of promoting this interaction by conjugating dyes with chitosan. The fluorescent properties of conjugated dye–montmorillonite (MMT) hybrids were similar to those of free dye–MMT hybrids. Moreover, we analyzed the relationship between the changes in optical properties of the dye interacting with clay and its structure and defined the physical and chemical mechanisms that take place upon dye–MMT interactions leading to the optical changes. Conjugation to chitosan additionally ensures stable adsorption on clay nanoplatelets due to the strong electrostatic interaction between chitosan and clay. This work thus provides a method to facilitate the design of solid-state hybrid nanomaterials relevant for potential applications in bioimaging, sensing and optical purposes.

scholarly journals Groundwater physico-chemical properties and water quality changes in shallow aquifers in arid saline wetlands, Ouargla, Algeria

2021 ◽  
Vol 11 (5) ◽  
Author(s):  
Fethi Medjani ◽  
Mohamed Djidel ◽  
Sofiane Labar ◽  
Louiza Bouchagoura ◽  
Chouaib Rezzag Bara
Keyword(s):  
Water Quality ◽  
Chemical Properties ◽  
High Water ◽  
Quality Changes ◽  
Shallow Aquifers ◽  
Shallow Water Table ◽  
Chemical Mechanisms ◽  
Desert Region ◽  
Physico Chemical ◽  
Hypersaline Water

AbstractShallow aquifers are vulnerable to natural geogenic processes as well as anthropogenic influences, and this is especially apparent in desert regions. Within arid and hyperarid climates, evaporation is a controlling hydrologic process leads to an important increase in the concentration of dissolved minerals of both surface water and groundwater. In groundwater, this increase is not only dependent on shallow water table depth, but also on the hydraulic properties of sediments present within the unsaturated zone of the aquifer itself. The main objective of this research is to investigate possible mechanisms that might influence water quality changes under seasonal conditions in shallow aquifers situated within the Saharan desert region of Algeria. In this work, we focus on observed changes in hydrogeochemical characteristics, and the possible responsible processes. Under arid conditions, high water mineralization results in hypersaline water or brine solution formation within shallow aquifers. Due to active physico-chemical mechanisms such as Na+/Ca2+ ion exchange, the successive precipitation of calcite, gypsum, mirabilite or blœdite and halite is induced. Biological processes were also observed as prevalent; evidenced by large measured variations in CO2 load concentrations. These processes contributed to an inverse relationship between CO2 and O2 concentrations within the shallow aquifers studied.

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