scholarly journals Organosilane self-assembled multilayer formation based on activation of methyl-terminated surface with reactive oxygen species generated by vacuum ultra-violet excitation of atmospheric oxygen molecules

2009 ◽  
Vol 256 (5) ◽  
pp. 1507-1513 ◽  
Author(s):  
Young-Jong Kim ◽  
Jiwon Han ◽  
Hikaru Sano ◽  
Kyung-Hwang Lee ◽  
Kei Noda ◽  
...  
2018 ◽  
Vol 30 (8) ◽  
pp. 1704877 ◽  
Author(s):  
Yunlu Dai ◽  
Zhen Yang ◽  
Siyuan Cheng ◽  
Zhongliang Wang ◽  
Ruili Zhang ◽  
...  

2013 ◽  
Vol 60 (4) ◽  
Author(s):  
Anna Ząbek-Adamska ◽  
Ryszard Drożdż ◽  
Jerzy W Naskalski

Histidine-copper(II) complex (Cu-His2) is a form of bound copper necessary for cellular copper uptake. Due to the high affinity of histidine to copper(II) ions, the binding of copper(II) by histidine is considered a substantial part of plasma antioxidative defense. Also cysteine plays a role in the antioxidative system. However, we show here that in the presence of oxygen the histidine-copper(II) complex plus cysteine produces reactive oxygen species (ROS). Cysteine concentration was assayed using a thiol specific silver-mercury electrode. Hydrogen peroxide was assayed amperometrically using platinum electrode. ROS formation was followed by chemiluminescence of luminol-fluoresceine-enhanced system. Addition of cysteine to Cu-His2 solution at pH 7.4 in the presence of atmospheric oxygen initiates the synthesis of H2O2 and generation of ROS, which manifests as a burst of chemiluminescence. The reaction has two stages; in the first stage, cysteine is utilized for the synthesis of an unstable intermediary product which becomes a substrate for ROS formation. Anaerobic conditions inhibit ROS formation. Increased cysteine concentration enhances the lag phase of the oxidative burst without influencing the amount of ROS. The synthesis of ROS (measured by chemiluminescence) is proportional to the concentration of Cu-His2 employed. ROS production can be repetitively initiated by further additions of cysteine to the reaction medium. The study suggests that Cu-His2 catalyzes cysteine-dependent reduction of oxygen to superoxide employing an intermediary cysteine-copper(I) complex and enabling Fenton reaction with copper and hydrogen peroxide produced as a secondary product. In effect, Cu-His2 with cysteine may be a source of ROS in biological media.


F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1574 ◽  
Author(s):  
Dhanalakshmi Vadivel ◽  
Ilanchelian Malaichamy

SiO2 and carbon produced by kraft lignin pyrolyzed at 600°C can generate stable reactive oxygen species (ROS) by reaction with atmospheric oxygen. In this study, we systematically investigate the photochemistry of peroxyl radicals in carbon-supported silica (PCS) and assess its effects on the methylene blue (MB) photodegradation. Characterization revealed that the higher ROS generation ability of SiO2/carbon under UV light irradiation was attributed to its abundant photoactive surface-oxygenated functional groups.


ACS Omega ◽  
2019 ◽  
Vol 4 (5) ◽  
pp. 8290-8298 ◽  
Author(s):  
Baillie A. DeHaven ◽  
Hannah K. Liberatore ◽  
Alexander Greer ◽  
Susan D. Richardson ◽  
Linda S. Shimizu

2020 ◽  
Vol 8 (3) ◽  
pp. 112-117
Author(s):  
Ievgeniia Kocherova ◽  
Rut Bryl ◽  
Igor Crha ◽  
Pavel Ventruba ◽  
Jana Zakova ◽  
...  

AbstractIn the female reproductive tract, reactive oxygen species (ROS) may exert physiological and pathophysio-logical effects. Although ROS play an essential role as the signaling molecules, their excessive accumulation contributes to the pathogenesis of many reproductive processes. In the ovarian follicle, ROS affect multiple physiological processes, including oocyte maturation and fertilization. However, a lack of studies showing to which extend ovarian granulosa and cumulus cells can contribute to the development of oxidative stress within the ovarian follicle. In the presented research, the extracellular ROS accumulation level was investigated using GCs and CCs primary in vitro cultures. The obtained results demonstrated a steady decrease in extracellular ROS level during GCs primary culture. By contrast, ROS concentration in CCs conditioned medium increased gradually between the first and the seventh days of culture. The observed changes may reflect the proliferation status and metabolic activity of GCs and CCs during in vitro culture. Additionally, the elevated ROS level at respective points of time could occur as a consequence of culture in atmospheric oxygen. The distinct function and localization within the ovarian follicle may explain the differences between GCs and CCs oxygen metabolism.Running title: Reactive oxygen species in primary culture of human follicular cells


2019 ◽  
Vol 7 (5) ◽  
pp. 1905-1918 ◽  
Author(s):  
Wei Tong ◽  
Yanhua Xiong ◽  
Shun Duan ◽  
Xiaokang Ding ◽  
Fu-Jian Xu

Self-assembled PGED-Pc nanoparticles are able to inactivate bacteria via the generation of reactive oxygen species in aqueous solution, while a facile immobilization strategy sheds light on the engineering of self-sterilizing surfaces to combat bacterial infections.


2020 ◽  
Vol 15 (4) ◽  
pp. 259-271
Author(s):  
Anna Kędziora ◽  
Monika Katarzyna Lesiów ◽  
Katarzyna Krupa ◽  
Agnieszka Korzeniowska-Kowal ◽  
Ryszard Adamski ◽  
...  

Aim: Characterization of the ability of Fusobacterium nucleatum DSM 15643 and DSM 20482 strains in the presence of Cu2+ and H2O2 to reactive oxygen species generation. Method: Spectrophotometric ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) method was used. Results: Determination of: MIC for Cu2+, H2O2 and ABTS; survivability of F. nucleatum under atmospheric oxygen exposure; the level and rate constants of free radicals production by the bacteria. Conclusion: F. nucleatum in the presence of Cu2+ and H2O2 is able to generate free radicals. Reactive oxygen species are produced mainly outside the bacterial cell, which suggests that outer membrane proteins may be involved in oxidative process.


2009 ◽  
pp. c3 ◽  
Author(s):  
Helena M. Cochemé ◽  
Michael P. Murphy

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