Species-Specific Standard Redox Potential of Thiol-Disulfide Systems: A Key Parameter to Develop Agents against Oxidative Stress

Microscopic redox equilibrium constants and standard redox potential values were determined to quantify selenolate-diselenide equilibria of biological significance. The highly composite, codependent acid-base and redox equilibria of selenolates could so far be converted into pH-dependent, apparent parameters (equilibrium constants, redox potentials) only. In this work, the selenolate-diselenide redox equilibria of selenocysteamine and selenocysteine against dithiothreitol were analyzed by quantitative nuclear magnetic resonance (NMR) methods to characterize the interfering acid-base and redox equilibria. The directly obtained, pH-dependent, conditional redox equilibrium constants were then decomposed by our method into pH-independent, microscopic constants, which characterize the two-electron redox transitions of selenocysteamine and selenocysteine. The 12 different, species-specific parameter values show close correlation with the respective selenolate basicities, providing a tool to estimate otherwise inaccessible site-specific selenolate-diselenide redox potentials of related moieties in large peptides and proteins.

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Using redox potential as a feasible marker for banked blood quality and the state of oxidative stress in stored red blood cells

Journal of Clinical Laboratory Analysis ◽

10.1002/jcla.23955 ◽

2021 ◽

Author(s):

Rodney C. Daniels ◽

Hyesun Jun ◽

Robertson D. Davenport ◽

Maryanne M. Collinson ◽

Kevin R. Ward

Keyword(s):

Oxidative Stress ◽

Redox Potential ◽

Red Blood Cells ◽

Blood Cells ◽

The State

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Dithienylpyrrole Electrografting on a Surface through the Electroreduction of Diazonium Salts

Electrochem ◽

10.3390/electrochem1010003 ◽

2020 ◽

Vol 1 (1) ◽

pp. 20-31

Author(s):

Thi Huong Le ◽

Van Quyen Nguyen ◽

Gaelle Trippe-Allard ◽

Jean-Christophe Lacroix ◽

Pascal Martin

Keyword(s):

Electron Transfer ◽

Redox Potential ◽

Diazonium Salts ◽

Organic Thin Film ◽

Organic Film ◽

Aniline Derivative ◽

Standard Redox Potential ◽

Key Issues ◽

Adhesion Process

The control of the interface and the adhesion process are key issues for the development of new application based on electrochromic materials. In this work the functionalization of an electrode’s surface through electroreduction of diazonium generated in situ from 4-(2,5-di-thiophen-2-yl-pyrrol-1-yl)-phenylamine (SNS-An) has been proposed. The synthesis of the aniline derivative SNS-An was performed and the electrografting was investigated by cyclic voltammetry on various electrodes. Then the organic thin film was fully characterized by several techniques and XPS analysis confirms the presence of an organic film based on the chemical composition of the starting monomer and allows an estimation of its thickness confirmed by AFM scratching measurements. Depending on the number of electrodeposition cycles, the thickness varies from 2 nm to 10 nm, which corresponds to a few grafted oligomers. In addition, the grafted film showed a good electrochemical stability depending on the scan rates up to 400 V/s and the electrochemical response of the modified electrode towards several redox probes showed that the attached layer acts as a conductive switch. Therefore, the electrode behaves as a barrier to electron transfer when the standard redox potential of the probe is below the layer switching potential, whereas the layer can be considered as transparent towards the electron transfer for redox probes with a redox potential above it.

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Estimation of above-ground phytomass and carbon in tree resources outside the forest (TROF): A geo-spatial approach

Banko Janakari ◽

10.3126/banko.v24i1.13488 ◽

2015 ◽

Vol 24 (1) ◽

pp. 34-40 ◽

Cited By ~ 3

Author(s):

B. P. Heyojoo ◽

S. Nandy

Keyword(s):

Satellite Image ◽

Uttar Pradesh ◽

Individual Species ◽

Individual Tree ◽

Spatial Approach ◽

Specific Standard ◽

Vegetation Carbon ◽

Carbon Project ◽

The Individual ◽

Species Specific

This study aims to estimate above-ground phytomass and carbon of TROF ecosystem in part of Bijnor district in Uttar Pradesh state of India using IRS P6 LISS-IV satellite image by geo-spatial approach coupled with field sampling. Chacko’s formula was referred to compute number of samples in each TROF types and the sample plot size in each stratum was adopted from Vegetation Carbon Project (VCP) under National Carbon Project (NCP). With the help of field data consisting mainly the height and girth information, volume of each individual tree per plot was obtained using site and tree species-specific standard volumetric equations. The phytomass was calculated by multiplying volume with Biomass Expansion Factor (BEF) then with regional specific gravity of the individual species and summed up in each plot to get total phytomass per plot. The total phytomass per plot was reported to be maximum 544.00 t/ha for linear TROF followed by 121.89 t/ha for block TROF. The carbon from phytomass was obtained by multiplying the total phytomass by a conversion factor that represents the average carbon content in phytomass. Spectral modeling for phytomass with different bands and indices were established and the best fit curve (R2 = 0.552) with red band was applied to generate phytomass and carbon distribution map of the study area.Banko Janakari, Vol. 24, No. 1, pp. 34-40

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Using Redox Potential as a Feasible Marker for Banked Blood Quality and the State of Oxidative Stress in Stored Red Blood Cells

10.21203/rs.3.rs-104378/v1 ◽

2020 ◽

Author(s):

Rodney C Daniels ◽

Hyesun Jun ◽

Robertson D Davenport ◽

Maryanne M Collinson ◽

Kevin R Ward

Keyword(s):

Oxidative Stress ◽

Redox Potential ◽

Red Blood Cells ◽

Healthy Volunteers ◽

Blood Cells ◽

Storage Time ◽

Cell Function ◽

Venous Blood ◽

Functional Changes ◽

Over Time

Abstract Background Stored Red Blood Cells (RBCs) may undergo oxidative stress over time, with functional changes affecting critical tasks such as oxygen delivery. Central to these changes are oxidation-reduction (redox) reactions and the redox potential (RP) that must be maintained for proper cell function. RP imbalance can lead to oxidative stress that may contribute to storage lesions and transfusion-related morbidities. Direct measures of RP may allow for evaluation of erythrocyte quality and enable corrections of RP prior to transfusion. Methods Multiple random RBC segments were tested, ranging in age from 5 to 40 days at 5 day intervals. RP was recorded by measuring open circuit potential of RBCs using novel nanoporous gold electrodes with Ag/AgCl reference. RP measures were also performed on peripheral venous blood samples from 10 healthy volunteers. RP measures were compared between groups of aged RBCs, and with volunteer blood. Results Stored RBCs show time-dependent increases in RP. There were significant differences in Day 5 RP compared to all other groups (p≤0.005), Day 10-15 vs ages ≥ Day 20 (p≤0.025), Day 20-25 vs Day 40 (p=0.039), and all groups compared to healthy volunteers. RP became more positive over time suggesting ongoing oxidation as RBCs age. However, storage time alone does not predict the ultimate RP value measured from a given unit.Conclusions There are significant differences in RP between freshly stored RBCs and all others, with RP becoming more positive over time. However, storage time alone does not predict RP, indicating RP screening may be important independent of storage time and may serve as a marker of RBC quality and state of oxidative stress. RP measurements may also provide a target by which to restore RP balance in aged pRBCs, improving their clinical effectiveness while reducing associated morbidities.

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Theoretical interpretation of the standard redox potential of benzene-1,2-diol and its derivatives

The Journal of Physical Chemistry ◽

10.1021/j150623a029 ◽

1981 ◽

Vol 85 (23) ◽

pp. 3510-3513 ◽

Cited By ~ 5

Author(s):

Shinichi Yamabe ◽

Tsutomu Minato ◽

Masaru Kimura

Keyword(s):

Redox Potential ◽

Theoretical Interpretation ◽

Standard Redox Potential

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Redox potential as a key parameter for monitoring and optimization of xylose fermentation with yeast Spathaspora passalidarum under limited-oxygen conditions

Bioprocess and Biosystems Engineering ◽

10.1007/s00449-020-02344-2 ◽

2020 ◽

Vol 43 (8) ◽

pp. 1509-1519 ◽

Cited By ~ 1

Author(s):

Carolina I. D. G. Bonan ◽

Luiz E. Biazi ◽

Suzane R. Dionísio ◽

Lauren B. Soares ◽

Robson Tramontina ◽

...

Keyword(s):

Redox Potential ◽

Xylose Fermentation ◽

Oxygen Conditions ◽

Spathaspora Passalidarum ◽

Key Parameter ◽

Limited Oxygen

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The Standard Redox Potential of the Phenyl Radical/Anion Couple

Journal of the American Chemical Society ◽

10.1021/ja0374574 ◽

2003 ◽

Vol 125 (48) ◽

pp. 14801-14806 ◽

Cited By ~ 125

Author(s):

Claude P. Andrieux ◽

Jean Pinson

Keyword(s):

Redox Potential ◽

Radical Anion ◽

Phenyl Radical ◽

Standard Redox Potential

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Boron Oxide Nanoparticles Exhibit Minor, Species-Specific Acute Toxicity to North-Temperate and Amazonian Freshwater Fishes

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.689933 ◽

2021 ◽

Vol 9 ◽

Author(s):

Tyson J. MacCormack ◽

Patrick T. Gormley ◽

B. Ninh Khuong ◽

Olivia A. Adams ◽

Susana Braz-Mota ◽

...

Keyword(s):

Oxidative Stress ◽

Acute Toxicity ◽

Boron Oxide ◽

Model Systems ◽

Oxide Nanoparticles ◽

Frequency Distributions ◽

Aerobic Activity ◽

The North ◽

Aquatic Vertebrates ◽

Species Specific

Boron oxide nanoparticles (nB2O3) are manufactured for structural, propellant, and clinical applications and also form spontaneously through the degradation of bulk boron compounds. Bulk boron is not toxic to vertebrates but the distinctive properties of its nanostructured equivalent may alter its biocompatibility. Few studies have addressed this possibility, thus our goal was to gain an initial understanding of the potential acute toxicity of nB2O3 to freshwater fish and we used a variety of model systems to achieve this. Bioactivity was investigated in rainbow trout (Oncorhynchus mykiss) hepatocytes and at the whole animal level in three other North and South American fish species using indicators of aerobic metabolism, behavior, oxidative stress, neurotoxicity, and ionoregulation. nB2O3 reduced O. mykiss hepatocyte oxygen consumption (ṀO2) by 35% at high doses but whole animal ṀO2 was not affected in any species. Spontaneous activity was assessed using ṀO2 frequency distribution plots from live fish. nB2O3 increased the frequency of high ṀO2 events in the Amazonian fish Paracheirodon axelrodi, suggesting exposure enhanced spontaneous aerobic activity. ṀO2 frequency distributions were not affected in the other species examined. Liver lactate accumulation and significant changes in cardiac acetylcholinesterase and gill Na+/K+-ATPase activity were noted in the north-temperate Fundulus diaphanus exposed to nB2O3, but not in the Amazonian Apistogramma agassizii or P. axelrodi. nB2O3 did not induce oxidative stress in any of the species studied. Overall, nB2O3 exhibited modest, species-specific bioactivity but only at doses exceeding predicted environmental relevance. Chronic, low dose exposure studies are required for confirmation, but our data suggest that, like bulk boron, nB2O3 is relatively non-toxic to aquatic vertebrates and thus represents a promising formulation for further development.

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