scholarly journals Methods to Determine Chain-Breaking Antioxidant Activity of Nanomaterials beyond DPPH•. A Review

Antioxidants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1551
Author(s):  
Andrea Baschieri ◽  
Riccardo Amorati
Keyword(s):  
Antioxidant Activity ◽  
Chemical Methods ◽  
Testing Conditions ◽  
Radical Trapping ◽  
Chain Breaking ◽  
Stable Radicals ◽  
Further Development ◽  
Selection Of ◽  
Made In

This review highlights the progress made in recent years in understanding the mechanism of action of nanomaterials with antioxidant activity and in the chemical methods used to evaluate their activity. Nanomaterials represent one of the most recent frontiers in the research for improved antioxidants, but further development is hampered by a poor characterization of the ‘‘antioxidant activity’’ property and by using oversimplified chemical methods. Inhibited autoxidation experiments provide valuable information about the interaction with the most important radicals involved in the lipid oxidation, namely alkylperoxyl and hydroperoxyl radicals, and demonstrate unambiguously the ability to stop the oxidation of organic materials. It is proposed that autoxidation methods should always complement (and possibly replace) the use of assays based on the quenching of stable radicals (such as DPPH• and ABTS•+). The mechanisms leading to the inhibition of the autoxidation (sacrificial and catalytic radical trapping antioxidant activity) are described in the context of nanoantioxidants. Guidelines for the selection of the appropriate testing conditions and of meaningful kinetic analysis are also given.

Chain-Breaking Antioxidant Activity and Cyclic Voltammetry Characterization of Polyphenols in a Range of Green, Oolong, and Black Teas

2003 ◽  
Vol 51 (19) ◽  
pp. 5798-5802 ◽  
Author(s):  
Vitaly Roginsky ◽  
Tatyana Barsukova ◽  
Chyong F. Hsu ◽  
Paul A. Kilmartin
Keyword(s):  
Antioxidant Activity ◽  
Cyclic Voltammetry ◽  
Chain Breaking

scholarly journals Effect of Thermal Process and Filtration on the Antioxidant Activity and Physicochemical Parameters of Agave atrovirens Extracts

2014 ◽  
Vol 4 (1) ◽  
pp. 155 ◽  
Author(s):  
Victor Olvera-Garcia ◽  
Anaberta Cardador-Martinez ◽  
Sandra T. Martin del Campo
Keyword(s):  
Antioxidant Activity ◽  
Thermal Process ◽  
Negative Impact ◽  
Biological Properties ◽  
Solid Content ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Evaporation Increase ◽  
Made In

<p>Recently agave plants are being used in the production of syrups that are consumed by diabetic people in order to control their blood glucose levels; unfortunately a deep characterization of this kind of products has not been made. In this study the juice obtained from <em>Agave atrovirens</em> leaves (CE) was filtered and cooked (FE) and evaporated until it has a solid content of 20 ºBx (TE), and the effect of the process in some parameters like pH, acidity, solid content, 5-Hydroxymethylfurfural (5-HMF) and compounds with biological properties like saponins and phenolic compounds as well as antioxidant activity were evaluated. Once FE was concentrated, a dark brown liquid with a pH of 5.32 was obtained; the content of phenolics and saponins undergoes slightly modifications trough the complete process. 5-HMF was only detected in CE but not in FE and TE. Filtering decrease acidity, total phenolics, saponins, 5-HMF and the antiradical activity (ARA); and evaporation increase the content of reducing sugars and tends to increase the ARA value. For this study, we can conclude that the negative impact associated to a thermal process on bioactive compounds like phenols and antioxidant activity is negligible hence <em>Agave atrovirens</em> leaves could be a source of a product with phytochemicals.</p>

Determination of Antioxidant Activity In Vitro from Hyptis rhomboidea Mart. et Gal. Ethanol Extracts

2014 ◽  
Vol 472 ◽  
pp. 824-828 ◽  
Author(s):  
Xi Feng Li ◽  
Lu Tang ◽  
Nan Nan Zheng ◽  
Shuo An ◽  
You Xu Wang ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
Positive Control ◽  
Fresh Market ◽  
Ethanol Extracts ◽  
Dpph Scavenging ◽  
Selection Of

Antioxidants are the chemical substances that reduce or prevent oxidation. The present study aimed to assess in vitro antioxidant activities of ethanol extracts Hyptis rhomboidea. DPPH, ABTS and FRAP assays were used for characterization of antioxidant activities of several extracts. Eventually, the promising extract was the ethyl acetate (EAc) extract, The analyzed extracts exhibited that antioxidant activities varied considerably as function of extracts. The highest DPPH• scavenging ability was found in Y6-8，which was divided from EAc by silica column, the lowest IC50 value (6.9μg/ml), followed by Y6-9 (11.7μg/ml) and the TEAC of Y6-8 and Y6-9were greater than positive control trolox. The same tendency was observed using ABTS and FRAP assays. These results suggest that the H. rhomboidea shows a better antioxidant activity, especially in the EAc extract and these results would be a guide in the selection of potential cultivars which are used in food and chemical industry and fresh market.

Applications of Transmission Electron Microscopy in the Characterization of Metal Machinability

1968 ◽  
Vol 26 ◽  
pp. 442-443 ◽  
Author(s):  
L.E. Murr ◽  
A.B. Draper
Keyword(s):  
Electron Microscopy ◽  
State Physics ◽  
Test Material ◽  
Milling Machine ◽  
Rotary Table ◽  
Solid State Physics ◽  
Materials Properties ◽  
Transmission Electron ◽  
Selection Of

The industrial characterization of the machinability of metals and alloys has always been a very arbitrarily defined property, subject to the selection of various reference or test materials; and the adoption of rather naive and misleading interpretations and standards. However, it seems reasonable to assume that with the present state of knowledge of materials properties, and the current theories of solid state physics, more basic guidelines for machinability characterization might be established on the basis of the residual machined microstructures. This approach was originally pursued by Draper; and our presentation here will simply reflect an exposition and extension of this research.The technique consists initially in the production of machined chips of a desired test material on a horizontal milling machine with the workpiece (specimen) mounted on a rotary table vice. A single cut of a specified depth is taken from the workpiece (0.25 in. wide) each at a new tool location.

WINTER WHEAT DEVELOPED BY THE UDMURT RESEARCH INSTITUTE OF AGRICULTURE IN COMPETITIVE VARIETY TESTING

2020 ◽  
pp. 5-16
Author(s):  
I.V. TORBINA ◽  
◽  
I.R. FARDEYEVA ◽  
Keyword(s):  
Winter Wheat ◽  
Crop Rotation ◽  
Biological Characteristics ◽  
Commercial Use ◽  
Breeding Material ◽  
Rotation Pattern ◽  
Selection Of ◽  
Variety Testing ◽  
Made In ◽  
Research Institute

The paper assesses the promising varieties of winter wheat in a competitive variety test by the main economic and biological characteristics that determine the suitability of the variety for commercial use. The object of research was the authors’ own breeding material. The experiments on the selection of winter wheat were made in the experimental crop rotation pattern of the Institute.

CRITERIONS FOR THE EFFECTIVENESS OF SOCIALLY IMPORTANT INVESTMENT PROJECTS AND THEIR FORMULAS ADOPTED IN RUSSIAN PRACTICE

2020 ◽  
Vol 2 (8) ◽  
pp. 58-64
Author(s):  
A. F. AGEEVA ◽  
Keyword(s):  
Performance Indicators ◽  
Payback Period ◽  
Internal Rate Of Return ◽  
Investment Projects ◽  
Regulatory Documents ◽  
Project Analysis ◽  
Analytical Work ◽  
Methodological Approaches ◽  
Further Development ◽  
Selection Of

The article analyzes domestic guidelines for assessing the effectiveness of investment projects reflected in the regulatory documentation, both current and invalid. Considered are methodological approaches to calculating key performance indicators of investment projects - net discounted income, internal rate of return, discounted payback period and profitability index. The results of the analysis and recommendations for the further development of national regulatory documents for project analysis and methodological approaches to assessing the effectiveness of socially significant investment projects are presented. The results of the analytical work presented in the article are planned to be used to create a methodology for the selection of socially significant projects for the provision of state support.

Caracterização da Peneira Média em Clones de Coffea canephora

REVISTA FIMCA ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 28-31
Author(s):  
Darlan Darlan Sanches Barbosa Alves ◽  
Victor Mouzinho Spinelli ◽  
Marcos Santana Moraes ◽  
Carolina Augusto De Souza ◽  
Rodrigo da Silva Ribeiro ◽  
...  
Keyword(s):  
Genetic Improvement ◽  
Block Design ◽  
Coffea Canephora ◽  
Coffee Production ◽  
Randomized Block Design ◽  
Significant Difference ◽  
The Mean ◽  
Four Blocks ◽  
Selection Of

Introdução: O estado de Rondônia se destaca como tradicional produtor de café, sendo o segundo maior produtor brasileiro de C. canephora. No melhoramento genético de C. canephora, a seleção de plantas de elevada peneira média está associada à bebida de qualidade superior. Objetivos: O objetivo desse estudo foi avaliar a variabilidade genética de clones de C. canephora para o tamanho dos grãos, mensurado a partir da avaliação da peneira média (PM). Materiais e Métodos: Para isso, foi conduzido ao longo de dois anos agrícolas experimento no campo experimental da Embrapa no município de Ouro Preto do Oeste-RO, para a avaliação da peneira média de 130 genótipos (clones) com características das variedades botânicas Conilon, Robusta e híbridos intervarietais. O delineamento experimental utilizado foi de blocos ao acaso, com quatro repetições de quatro plantas por parcela. Resultados: Não houve resultados significativos para a interação clones X anos, indicando uma maior consistência no comportamento das plantas ao longo do tempo. Porém foram observadas diferenças significativas para o tamanho dos grãos entre os genótipos avaliados, possibilitando selecionar genótipos superiores. Conclusão: Os genótipos agruparam-se em cinco classes de acordo com o teste de média, subsidiando a caracterização de um gradiente de variabilidade da característica avaliada ABSTRACTIntroduction: Coffea canephora accounts for approximately 35% of the world's coffee production. The state of Rondônia stands out as a traditional coffee producer, being the second largest Brazilian producer of C. canephora. In the classical genetic improvement of C. anephora, the selection of plants of high average sieve is associated with a drink of superior quality. Objectives: The objective of this udy was to evaluate the genetic variability of Coffea canephora clones for the agronomic medium sieve (PM). Materials and Methods: The experiment was conducted in the experimental field of Embrapa, municipality of OuroPreto do Oeste-RO, located at coordinates 10º44'53 "S and 62º12'57". One hundred thirty genotypes (clones) of botanical characteristics Conilon, Robusta and intervarietal hybrids were evaluated in the agricultural years 2013-2014 and 2014-2015. The experimental design was a randomized block design with four blocks and four plants per plot, spacing 3.5 x 1.5 meters between plants. Results: Significant difference was found for the grain size. According to the F test, at 5% probability, the genotypes were grouped into five classes according to the mean test. Conclusion: The results obtained subsidized the characterization of a variability gradient of the evaluated trait.

Bioactivity of Marine Natural Product Xyloketals

2020 ◽  
Vol 17 ◽  
Author(s):  
Biswajit Panda ◽  
Amal Kumar Gooyee
Keyword(s):  
Natural Products ◽  
Marine Natural Product ◽  
Ischemic Brain Injury ◽  
Ischemic Brain ◽  
Activity Inhibition ◽  
Life Saving ◽  
Behavior Suppression ◽  
Major Emphasis ◽  
Made In

: Oceans can play a major role in supplying life-saving medicines in the world in future. Although considerable progress has been made in finding new medicines from marine sources, large efforts are still necessary to examine such molecules for clinical applications. Xyloketals are an important group of natural products with various powerful and prominent bioactivities such as inhibition of acetylcholine esterase, antioxidant activity, inhibition of L-calcium channels, radicalscavenging behavior, suppression of cell proliferation, reduction of neonatal hypoxic-ischemic brain injury, etc. This review describes the isolation and structural characterization of all xyloketal natural products giving major emphasis on their bioactivity.

Characterization of Auditory Disability and Its Relation to the Resilience

2018 ◽  
Vol 5 (2) ◽  
pp. 15
Author(s):  
Bibian Bibeca Bumbila García ◽  
Hernán Andrés Cedeño Cedeño ◽  
Tatiana Moreira Chica ◽  
Yaritza Rossana Parrales Ríos
Keyword(s):  
Social Integration ◽  
Conceptual Analysis ◽  
Disabled People ◽  
Disabled Students ◽  
Hearing Disability ◽  
Technical University ◽  
The Relationship ◽  
Made In

The objective of the work is to establish the characterization of the auditory disability and its relationship with resilience at the Technical University of Manabí. The article shows a conceptual analysis related to the inclusion and social integration of disabled students. Based on the fact that the person with disabilities grows and develops in the same way as that of people without disabilities and what usually happens is that disabled people are rejected and discriminated against based on a prefabricated and erroneous conceptualization of these people. The results associated with the application of the SV-RES test prepared by the researchers are shown (Saavedra & Villalta, 2008b). Characterization of the auditory deficit is made in the students, and the limitations that derive from it are pointed out. We analyze the particularities related to communication with students who have a hearing disability and resilience in this type of student, where some personal highlights that in this sense constitute an example of resilience. Finally, the results related to the study of the relationship between students' hearing disability and the level of resilience dimensions are shown.

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