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Chlorine reactivity

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https://www.readbyqxmd.com/read/28420885/oxidative-stress-protein-damage-and-repair-in-bacteria
#1
REVIEW
Benjamin Ezraty, Alexandra Gennaris, Frédéric Barras, Jean-François Collet
Oxidative damage can have a devastating effect on the structure and activity of proteins, and may even lead to cell death. The sulfur-containing amino acids cysteine and methionine are particularly susceptible to reactive oxygen species (ROS) and reactive chlorine species (RCS), which can damage proteins. In this Review, we discuss our current understanding of the reducing systems that enable bacteria to repair oxidatively damaged cysteine and methionine residues in the cytoplasm and in the bacterial cell envelope...
April 19, 2017: Nature Reviews. Microbiology
https://www.readbyqxmd.com/read/28418706/radiation-driven-formation-of-reactive-oxygen-species-in-oxychlorine-containing-mars-surface-analogues
#2
Christos D Georgiou, Dimitrios Zisimopoulos, Electra Kalaitzopoulou, Richard C Quinn
The present study demonstrates that γ-radiolyzed perchlorate-containing Mars soil salt analogues (in a CO2 atmosphere) generate upon H2O wetting the reactive oxygen species (ROS) superoxide radical (O2(•-)), hydrogen peroxide (H2O2), and hydroxyl radicals ((•)OH). This study also validates that analogue radiolysis forms oxychlorine species that, in turn, can UV-photolyze to (•)OH upon UV photolysis. This investigation was made possible by the development of a new assay for inorganic-origin O2(•-) and H2O2 determination and by the modification of a previous assay for soil (•)OH...
April 2017: Astrobiology
https://www.readbyqxmd.com/read/28418689/an-official-american-thoracic-society-workshop-report-chemical-inhalational-disasters-biology-of-lung-injury-development-of-novel-therapeutics-and-medical-preparedness
#3
Eleanor M Summerhill, Gary W Hoyle, Sven-Eric Jordt, Bronwen J Jugg, James G Martin, Sadis Matalon, Steven E Patterson, David J Prezant, Alfred M Sciuto, Erik R Svendsen, Carl W White, Livia Veress
This report is based upon the proceedings from the Inhalational Lung Injury Workshop jointly sponsored by the American Thoracic Society (ATS) and the National Institute of Health (NIH)/National Institute of Neurologic Disorders and Stroke (NINDS) Countermeasures Against Chemical Threats (CounterACT) program on May 21, 2013 in Philadelphia, PA. The CounterACT program facilitates research leading to the development of new and improved medical countermeasures for chemical threat agents. The workshop was initiated by the Terrorism and Inhalational Disasters (TID) Section of the Environmental, Occupational, and Population Health Assembly (EOPH) of the ATS...
April 18, 2017: Annals of the American Thoracic Society
https://www.readbyqxmd.com/read/28405852/chlorinated-flavonoids-modulate-the-inflammatory-process-in-human-blood
#4
Carina Proença, Daniela Ribeiro, Tânia Soares, Sara M Tomé, Artur M S Silva, José L F C Lima, Eduarda Fernandes, Marisa Freitas
Flavonoids are known to react with neutrophil-generated hypochlorous acid (HOCl) at inflammation loci to form stable mono- and dichlorinated products. Some of these products have been shown to retain or even enhance their inflammatory potential, but further information is required in a broader approach to inflammatory mechanisms. In that sense, we performed an integrated evaluation on the anti-inflammatory potential of a panel of novel chlorinated flavonoids and their parent compounds, in several steps of the complex inflammatory cascade, namely, in the activity of cyclooxygenase (COX)-1 and COX-2, and in the production of cytokines [interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)], and the chemokine, IL-8, as well as in the production of reactive species, using human whole blood as a representative in vitro model, establishing, whenever possible, a structure-activity relationship...
April 13, 2017: Inflammation
https://www.readbyqxmd.com/read/28402665/kinetic-modeling-of-the-thermal-destruction-of-nitrogen-mustard-gas
#5
Juan-Carlos Lizardo-Huerta, Baptiste Sirjean, Laurent Verdier, René Fournet, Pierre-Alexandre Glaude
The destruction of stockpiles or unexploded ammunitions of nitrogen mustard (tris(2-chloroethyl)amine, HN-3) requires the development of safe processes. The thermal destruction of this kind of compound is one of the most efficient method of destruction. Because of the high-level of toxicity of this chemical, there is a considerable lack of knowledge on the chemical kinetics at high temperatures. In this study, a detailed chemical kinetic model for the pyrolysis of nitrogen mustard gas is developed based on a large number of thermokinetic parameters calculated with theoretical chemistry...
April 20, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28391120/transformation-of-acesulfame-in-chlorination-kinetics-study-identification-of-byproducts-and-toxicity-assessment
#6
Adela Jing Li, Pengran Wu, Japhet Cheuk-Fung Law, Chi-Hang Chow, Cristina Postigo, Ying Guo, Kelvin Sze-Yin Leung
Acesulfame (ACE) is one of the most commonly used artificial sweeteners. Because it is not metabolized in the human gut, it reaches the aquatic environment unchanged. In the present study, the reactivity of ACE in free chlorine-containing water was investigated for the first time. The degradation of ACE was found to follow pseudo-first-order kinetics. The first-order rate increased with decreasing pH from 9.4 to 4.8 with estimated half-lives from 693 min to 2 min. Structural elucidation of the detected transformation products (TPs) was performed by ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry...
March 28, 2017: Water Research
https://www.readbyqxmd.com/read/28362784/pseudo-actinometry-for-the-measurement-of-reactive-species-density
#7
Minwook Kang, Yunhyeok Ko, Il-Yong Jang, Junhwa Jung, Jae W Hahn
To compensate for the effect of plasma parameters in the signal of optical emission spectroscopy, we should normalize the emission intensity from the species against that of an inert gas (i.e., the actinometer). In many plasma processes in the semiconductor industry, plasma etching without using a neutral gas for the actinometer has become popular to achieve better critical dimension uniformity. We propose "pseudo actinometry" for normalization in the absence of an inert gas in the process plasma. Based on the theory of optical actinometry, we define a correction factor as the ratio of the emission intensity to the number density of the inert gas...
April 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28358483/mechanistic-aspects-of-the-formation-of-adsorbable-organic-bromine-during-chlorination-of-bromide-containing-synthetic-waters
#8
Markus Langsa, Anna Heitz, Cynthia A Joll, Urs von Gunten, Sebastien Allard
During chlorination of bromide-containing waters, a significant formation of brominated disinfection byproducts is expected. This is of concern because Br-DBPs are generally more toxic than their chlorinated analogues. In this study, synthetic water samples containing dissolved organic matter (DOM) extracts and bromide were treated under various disinfection scenarios to elucidate the mechanisms of Br-DBP formation. The total concentration of Br-DBPs was measured as adsorbable organic bromine (AOBr). A portion of the bromine (HOBr) was found to react with DOM via electrophilic substitution (≤40%), forming AOBr, and the remaining HOBr reacted with DOM via electron transfer with a reduction of HOBr to bromide (≥60%)...
April 13, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28357978/monochloramine-loss-mechanisms-in-tap-water
#9
Qianyi Zhang Evan G R Davies James Bolton Yang Liu
Chloramination has been widely applied for drinking water disinfection, with monochloramine (NH₂Cl) the dominant chloramine species. However, under neutral pH, NH₂Cl can autodecompose and react with chemical components in drinking water, thus decreasing disinfection efficiency. In tap water, the NH₂Cl loss rate can be influenced by temperature, pH, Cl/N molar ratio, the initial NH₂Cl concentration and the natural organic matter (NOM) concentration. A good prediction of NH2Cl loss can assist in the operation of drinking water treatment plants...
March 1, 2017: Water Environment Research: a Research Publication of the Water Environment Federation
https://www.readbyqxmd.com/read/28330427/comparison-of-airway-response-in-na%C3%A3-ve-and-ovalbumin-sensitized-mice-during-short-term-inhalation-exposure-to-chlorine
#10
Mia Johansson, Åsa Gustafsson, Gunnar Johanson, Mattias Öberg
OBJECTIVE: It has been suggested that asthmatics are more susceptible than healthy individuals to airborne irritating chemicals in general. However, there is limited human data available to support this hypothesis due to ethical and practical difficulties. We explored a murine model of ovalbumin (OVA)-induced airway inflammation to study susceptibility during acute exposure to chemicals with chlorine as a model substance. METHODS: Naïve and OVA sensitized female BALB/c mice were exposed to chlorine at four different concentrations (0, 5, 30 and 80 ppm) for 15 minutes with online recording of the respiratory function by plethysmography...
February 2017: Inhalation Toxicology
https://www.readbyqxmd.com/read/28327749/mono-and-polynuclear-ag-i-complexes-of-n-functionalized-bis-diphenylphosphino-amine-dppa-type-ligands-synthesis-solid-state-structures-and-reactivity
#11
Alessio Ghisolfi, Christophe Fliedel, Pierre de Frémont, Pierre Braunstein
The reactivity of the N-functionalized DPPA-type ligands (Ph2P)2N(p-Z)C6H4 [Z = H (1a), SMe (1b), OMe (1c)] with AgBF4 was investigated and revealed an unexpected influence of the para substituent Z of the N-aryl ligand. In acetone, the mononuclear bis-chelated [Ag{(1a-1c)-P,P}2]BF4 (2a·BF4-2c·BF4) and dinuclear bridged [Ag2{μ2-(1a-1c)-P,P}2](BF4)2 [3a·(BF4)2-3c·(BF4)2] complexes were obtained with a 1 : 2 and 1 : 1 AgBF4/ligand molar ratio, respectively. While the molecular structures of 2a·BF4 and 2b·BF4 determined in the solid-state by X-ray diffraction revealed their mononuclear nature and the absence of cation/anion interaction, complexes 3b·(BF4)2 and 3c·(BF4)2 form 2D coordination polymers through intermolecular Ag-S or Ag-O interactions, respectively, involving the N-function of the respective DPPA-type ligand, and display direct interactions between one BF4 anion and both Ag(i) cations...
March 22, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28322024/au-nanoclusters-and-photosensitizer-dual-loaded-spatiotemporal-controllable-liposomal-nanocomposites-enhance-tumor-photodynamic-therapy-effect-by-inhibiting-thioredoxin-reductase
#12
Fuping Gao, Weiping Zheng, Liang Gao, Pengju Cai, Ru Liu, Yaling Wang, Qing Yuan, Yuliang Zhao, Xueyun Gao
Photodynamic therapy (PDT) is a minimally invasive therapeutic procedure of tumors with high selectivity and low side effect. However, it is usually not efficient in long-lasting tumor control. One of the main reasons is tumor cells develop some protective mechanisms that help them to deal with oxidative stress in the environment. The thioredoxin system in cancer is an important antioxidant defense system. Au nanoclusters could effectively inhibit thioredoxin reductase (TrxR) in tumor cell cytoplasm. Herein, Au nanoclusters and photosensitizer Chlorine 6 (Ce6) are co-loaded in spatiotemporal controllable liposomal nanocomposites...
March 21, 2017: Advanced Healthcare Materials
https://www.readbyqxmd.com/read/28319884/sodium-chlorate-induces-dna-damage-and-dna-protein-cross-linking-in-rat-intestine-a-dose-dependent-study
#13
Shaikh Nisar Ali, Fariheen Aisha Ansari, Hussain Arif, Riaz Mahmood
Sodium chlorate (NaClO3) is widely used in paper and pulp industries and as a non-selective herbicide. It is also a major by-product generated upon disinfection of drinking water by chlorine dioxide. In this study, we have investigated the genotoxicity of NaClO3 on the small intestine of rats. Adult male rats were divided into 5 groups: one control and four NaClO3 treated groups. The NaClO3 treated groups were given a single acute oral dose of NaClO3 (100, 250, 500 and 750 mg/kg body weight) and sacrificed 24 h later...
March 8, 2017: Chemosphere
https://www.readbyqxmd.com/read/28300663/1-2-dichloropropane-generates-phosphorylated-histone-h2ax-via-cytochrome-p450-2e1-mediated-metabolism
#14
Tatsushi Toyooka, Yukie Yanagiba, Megumi Suda, Yuko Ibuki, Rui-Sheng Wang
1,2-Dichloropropane (1,2-DCP), a synthetic chlorinated solvent, was recently classified as carcinogenic. Genotoxic events are known as a crucial step in the initiation of cancer. However, studies on the genotoxicity of 1,2-DCP are very limited, particularly studies investigating the mechanism behind DNA damage by 1,2-DCP. In this study, we examined the genotoxicity of 1,2-DCP using phosphorylated histone H2AX (γ-H2AX), a sensitive DNA damage marker. 1,2-DCP showed dose- (1-10mM: 4h) and time-dependent (1-24h: 5mM) γ-H2AX generation in cultured human hepatocytes (WRL-68) and cholangiocytes (MMNK-1)...
March 12, 2017: Toxicology Letters
https://www.readbyqxmd.com/read/28296395/chlorination-of-amino-acids-reaction-pathways-and-reaction-rates
#15
Zuo Tong How, Kathryn L Linge, Francesco Busetti, Cynthia A Joll
Chlorination of amino acids can result in the formation of organic monochloramines or organic dichloramines, depending on the chlorine to amino acid ratio (Cl:AA). After formation, organic chloramines degrade into aldehydes, nitriles and N-chloraldimines. In this paper, the formation of organic chloramines from chlorination of lysine, tyrosine and valine were investigated. Chlorination of tyrosine and lysine demonstrated that the presence of a reactive secondary group can increase the Cl:AA ratio required for the formation of N,N-dichloramines, and potentially alter the reaction pathways between chlorine and amino acids, resulting in the formation of unexpected byproducts...
April 12, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28292934/maltotriose-conjugation-to-a-chlorin-derivative-enhances-the-antitumor-effects-of-photodynamic-therapy-in-peritoneal-dissemination-of-pancreatic-cancer
#16
Akihisa Kato, Hiromi Kataoka, Shigenobu Yano, Kazuki Hayashi, Noriyuki Hayashi, Mamoru Tanaka, Itaru Naitoh, Tesshin Ban, Katsuyuki Miyabe, Hiromu Kondo, Michihiro Yoshida, Yasuaki Fujita, Yasuki Hori, Makoto Natsume, Takashi Murakami, Atsushi Narumi, Akihiro Nomoto, Aya Naiki-Ito, Satoru Takahashi, Takashi Joh
Peritoneal dissemination is a major clinical issue associated with dismal prognosis and poor quality of life for patients with pancreatic cancer; however, no effective treatment strategies have been established. Herein, we evaluated the effects of photodynamic therapy (PDT) with maltotriose-conjugated chlorin (Mal3-chlorin) in culture and in a peritoneal disseminated mice model of pancreatic cancer. The Mal3-chlorin was prepared as a water-soluble chlorin derivative conjugated with four Mal3 molecules to improve cancer selectivity...
March 14, 2017: Molecular Cancer Therapeutics
https://www.readbyqxmd.com/read/28284551/characterization-of-the-reactivity-and-chlorinated-products-of-carbazole-during-aqueous-chlorination
#17
Xiong Xu, Donghong Wang, Chunmei Li, Hongru Feng, Zijian Wang
Carbazole in source water is a potential precursor for toxic chlorocarbazoles in drinking water when chlorine is used as a disinfection agent in drinking water treatment plants. However, the reactivity of carbazole and the specific structures and predominant analogues of chlorocarbazoles produced during aqueous chlorination remain unknown. In this study, the aqueous chlorination of carbazole was performed to characterize its reactivity and the chlorinated products. Chlorocarbazoles generated from carbazole were identified by a comprehensive two-dimensional gas chromatography-mass spectrometry method, and their molecular structures were predicted by the Fukui index of electrophilic attack, f(-1)(r)...
March 9, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28283522/use-of-bacteria-to-stabilize-archaeological-iron
#18
Lucrezia Comensoli, Julien Maillard, Monica Albini, Frederic Sandoz, Pilar Junier, Edith Joseph
Iron artifacts are common among the findings of archaeological excavations. The corrosion layer formed on these objected requires stabilization after their recovery, without which the destruction of the item due to physicochemical damage is likely. Current technologies for the stabilization of the corrosion layer are lengthy and generate hazardous waste products. There is therefore a pressing need for an alternative method to stabilize the corrosion layer on iron objects. The aim of this study was to evaluate an alternative conservation-restoration method using bacteria...
March 10, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28256138/silver-catalyzed-c-sp-3-h-chlorination
#19
Jun Ozawa, Motomu Kanai
A silver-catalyzed chlorination of benzylic, tertiary, and secondary C(sp(3))-H bonds was developed. The reaction proceeded with as low as 0.2 mol % catalyst loading at room temperature under air atmosphere with synthetically useful functional group compatibility. The regioselectivity and reactivity tendencies suggest that the chlorination proceeded through a radical pathway, but an intermediate alkylsilver species cannot be ruled out.
March 3, 2017: Organic Letters
https://www.readbyqxmd.com/read/28255365/size-tunable-gd2o3-albumin-nanoparticles-conjugating-chlorin-e6-for-magnetic-resonance-imaging-guided-photo-induced-therapy
#20
Lijuan Zhou, Tao Yang, Junxing Wang, Qiaoli Wang, Xiaoyan Lv, Hengte Ke, Zhengqing Guo, Junkang Shen, Yong Wang, Chungen Xing, Huabing Chen
Protein nanoparticles as nanocarriers are of particular interest in the field of cancer therapy. Nevertheless, so far a facile fabrication of theranostic protein nanoparticles have been explored with limited success for cancer imaging and therapy. In this work, we demonstrate the controllable synthesis of size-tunable Gd2O3@albumin conjugating photosensitizer (PS) (GA-NPs) using hollow albumin as the nanoreactor for magnetic resonance imaging (MRI)-guided photo-induced therapy. The growth of Gd2O3 nanocrystals within the hollow nanoreactors is well regulated through reaction time, and a typical PS (e...
2017: Theranostics
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