Oxygen Species Research Articles

Reactive Species from Two-Signal Activated Macrophages Interfere with Their Oxygen Consumption Measurements.

Metabolic modulation of macrophage activation has emerged as a promising strategy lately in immunotherapeutics. However, macrophages have a broad spectrum of functions and thus, understanding the exact metabolic changes that drive a particular immune response, is of major importance. In our previous work, we have reported a key role of nitric oxide (NO●) in two(2)-signal activated macrophages [M(2-signals)]. Further characterization using metabolic analysis in intact cells, showed that the basal and maximal respiration levels of M(2-signals) were comparable, with cells being unresponsive to the injections-inducd mitochondrial stress. Here, we show that excessive NO● secretion by the M(2-signals) macrophages, interferes with the oxygen (O2) consumption measurements on cells using the seahorse metabolic analyzer. This is attributed mainly to the consumption of ambient oxygen by NO● to form NO2− and/or NO3− but also to the reduction of O2 to superoxide anion (O2●−) by stray electrons from the electron transport chain, leading to the formation of peroxynitrite (ONOO−). We found that reactive species-donors in the absence of cells, produce comparable oxygen consumption rates (OCR) with M(2-signals) macrophages. Furthermore, inhibition of NO● production, partly recovered the respiration of activated macrophages, while external addition of NO● in non-activated macrophages downregulated their OCR levels. Our findings are crucial for the accurate metabolic characterization of cells, especially in cases where reactive nitrogen or oxygen species are produced in excess.

PH/ROS Dual-Responsive Polymer–Drug-Based Nanocarriers: Click-Reaction Preparation and Fluorescence Imaging-Guided Chemotherapy and Photodynamic Therapy

In the past decades, polymer-drug conjugates of anticancer agents have gained much attention due to their enhanced aqueous solubility, improved pharmacokinetics, and better drug utilization than their conventional insoluble counterparts. Several polymer-drug conjugates have entered the third phase of clinical trials yet suffer from inherent deficiencies, including uncontrolled drug release and unclear degradation mechanisms. In this study, a pH/reactive oxygen species (ROS) dual-responsive PEG-doxorubicin (DOX) conjugate (denoted as TPD) was synthesized through acyl alkynyl-amine click reaction by PEG dipropiolate (PEGB), amine-terminated thioketal (TKL), and doxorubicin (DOX). Due to the generated ene-amine and thioketal in the backbone, the prepared amphiphilic TPD not only has a high drug loading ratio for photosensitizer chlorin e6 (Ce6) but also has the sensitivity to the acidic tumor microenvironment (TME) and ROS. Considering the complex conditions of TME, the prepared TPD@Ce6 nanoparticles (NPs) might respond to the relatively low pH and release Ce6 initially, and upon laser radiation, Ce6 produces abundant singlet oxygen (1O2) to achieve a programmable accelerated release of DOX and more Ce6 at the tumor site. In addition, the NIR fluorescence of DOX could monitor drug delivery and controlled release. The developed TPD@Ce6 NPs can realize the targeted tumor in combination therapy with negligible cytotoxicity on normal tissues.

Oxidative stress in leukemia and antioxidant treatment.

Oxidative stress is caused by the imbalance between the generation of free radicals/reactive oxygen species (ROS) and the antioxidant defense systems, which can activate various transcription factors and affect their transcriptional pathways. Oxidative stress plays an important role in the occurrence and development of leukemia and is closely related to the treatment and prognosis of leukemia. The standard chemotherapy strategies for the pre-treatment of leukemia have many drawbacks. Hence, the usage of antioxidants and oxidants in the treatment of leukemia is being explored and has been preliminarily applied. This article reviews the research progress of oxidative stress and leukemia. In addition, the application of antioxidants treatment in leukemia has been summarized.

G-C3N4 templated synthesis of the tubular CoFe/N doped carbon composite as advanced bifunctional oxygen electrocatalysts for zinc-air batteries

Rational incorporating transition metal into porous heteroatom-doped carbon is intensively investigated as an effective strategy to achieve high-performance and bifunctional requirements. Herein, we fabricated the hollow composite that CoFe alloy nanoparticles decorated on the tubular N-doped carbon (denoted as T-CoFe/NC) by soft-templating strategy. In order to effectively incorporate the CoFe alloy into nitrogen doped hollow carbon matrix, g-C3N4 nanotubes were selected as the template to attain high contents of nitrogen doping for tubular carbon matrix. Meanwhile, the coordination effect between tannic acid and metal ions is utilized to limit the metal agglomeration in the process of pyrolysis. Consequently, the resultant catalyst shows an outstanding ORR activity with the half-wave potential of 0.86 V and outstanding stability with only a 2 mV decay after 10,000 cycles. T-CoFe/NC also displays comparable overpotential to the RuO2 at 10 mA cm−2. The high bifunctional electrocatalytic activity is attributed to the unique tubular structure and the combination of Co with Fe can optimize the interaction between the oxygenic species and metal surfaces, enhancing the catalytic activity. And T-CoFe/NC based zinc-air battery exhibits excellent power density, large capacity and good cycling stability.

Abstract 681: Prospective study for the identification of DNA repair radiotoxicity biomarkers in breast and prostate cancer patients: Cohort description and descriptive statistics

Abstract Introduction: Radiotherapy (RT) can induce with short-term (acute) and long term toxicity. Although acute toxicity is generally well tolerated, long term toxicity might be irreversible and progressive over time. RT induces damage in healthy tissue, triggers inflammation and bystander effects in non-irradiated cells. The toxicity is dependent on many variables and precise knowledge on the responsible mechanisms is still lacking. Purpose: DNA damage, DNA repair and inflammation are known to interplay. Because of the specific involvement of Base Excision Repair (BER) in Reactive Oxygen and Nitrogen species (RONs)-induced lesions and inflammation, we monitored BER activities in patients receiving radiotherapy to investigate glycosylase/AP endonucleases activities as potential biomarkers of radiotoxicity. First, impact of gender, age, concomitant treatment, body mass index (BMI), smoking and alcohol consumption, on basal repair levels, and radiation-induced repair activities were evaluated. Methods: About 220 patients suffering from non-metastatic breast or prostate cancer and treated by radiotherapy (RT) were enrolled by Institut de Cancérologie Lucien Neuwirth. 8 mL of blood was collected prior to RT, 24h after the first radiation dose and before the 6th radiation dose. We then used the Glyco-SPOT assay to quantify BER activities, and nucleases level in lysates prepared from the patients' lymphocytes. Patients were followed-up for at least 6 months. Clinical and toxicity data were collected. All adverse events (AE; acute, sub-acute and late) were scored according to Common Terminology Criteria for Adverse Events. Results: Due to differences in the BER profile between prostate and breast cancer patients, the two groups were analyzed separately. We provide a descriptive overview of recorded AE for each group, according to time period. Some significant specific changes in BER activities where associated with smoking, alcohol consumption, BMI, treatment type and age. Conclusion: Known risk factors significantly affected some BER activities. Males and females should be considered independently for radiotoxicity biomarkers identification using glycosylase/AP endonuclease/nucleases related biomarkers. The identification of possible confounding factors is a prerequisite to any selection of radiotoxicity biomarkers. Citation Format: Sylvie Sauvaigo, Giovanna Muggiolu, Sarah Libert, Elisabeth Daguenet, Claire Rodriguez-Lafrasse, Thierry Maillet, Nicolas Magné. Prospective study for the identification of DNA repair radiotoxicity biomarkers in breast and prostate cancer patients: Cohort description and descriptive statistics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 681.

Abstract 996: Cold atmospheric plasma therapy selectively targets triple negative breast cancer cells

Abstract Background: Cancer cells notoriously escape radiation therapy, chemotherapy, hormonal therapy, and other anti-cancer therapies. Among various breast cancer subtypes, triple negative breast cancers (TNBCs) are known for their poor clinical outcome and dearth of effective targeted therapies due to the absence of druggable receptors. Cold atmospheric plasma (CAP) holds promise as a cancer-specific treatment agent that selectively kills basal-like/TN breast cancer cells. Method: In this study, we used plasma-activated media (PAM) to capture and store the multi-modal chemical species of CAP, which significantly expands the treatment scope and flexibility of plasma medicine as a clinical therapeutic approach. The PAM was diluted into different doses and cells were treated for 12 or 24 hours. The effects of PAM on cell viability and ROS levels in 9 different cell lines; normal cells (MCF-10A and HEK-293T), luminal breast cancer cell lines (MCF-7, T47D, HCC70), and TNBC cell lines (MDA-MB-468, SUM-159PT, SUM-149PT, MDA-MB-231), were assessed. Results: The results showed that TNBC cells were more highly sensitive, in a dose-dependent manner, to PAM treatment. PAM selectively caused apoptosis of TNBC cell lines compared to luminal lines and had little effect on the normal cell lines. It has been hypothesised that the cancer-selective CAP and PAM cytotoxicity is due in part to reactive oxygen (ROS) and nitrogen species (RNS). Constitutive RONS levels, combined with those present in and/or induced by PAM, can combine to push the cells over a cytotoxic threshold. In support of this, we found a tight correlation (R2=0.7502) between the constitutive ROS level of different cell lines used and their response (cell viability) to 100% PAM treatment, and found that ROS levels selectively increased further in the TNBC>luminal>normal cells in response to PAM. We have also identified a strong synergistic molecular partner that further promotes sensitivity and selectivity of PAM for TNBC cells. Conclusion: We demonstrated that treatment with PAM promotes apoptosis n cell lines representing the most aggressive TNBC subtype. This discovery opens new TNBC-selective opportunities for simultaneous inhibition of diverse (parallel) cancer development factors through synergistic interactions enabled through plasma activated biochemical media. Citation Format: Peiyu Wang, Renwu Zhou, Rusen Zhou, Jennifer Gunter, Fiona Simpson, Kostya (Ken) Ostrikov, Derek Richard, Xiaofeng Dai, Erik (Rik) Walter Thompson. Cold atmospheric plasma therapy selectively targets triple negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 996.

Safety and efficacy of a COVID-19 treatment with nebulized and/or intravenous neutral electrolyzed saline combined with usual medical care vs. usual medical care alone: A randomized, open-label, controlled trial.

Coronavirus disease 2019 (COVID-19) is currently the major public health problem worldwide. Neutral electrolyzed saline solution that contains reactive chlorine and oxygen species may be an effective therapeutic. In the present study, the treatment efficacy of intravenous and/or nebulized neutral electrolyzed saline combined with usual medical care vs. usual medical care alone was evaluated in ambulatory patients with COVID-19. A prospective, 2-arm, parallel-group, randomized, open-label, multi-center, phase I-II clinical trial including 214 patients was performed. The following two outcomes were evaluated during the 20-day follow-up: i) The number of patients with disease progression; and ii) the patient acceptable symptom state. Serial severe acute respiratory syndrome coronavirus 2 naso/oro-pharyngeal detection by reverse transcription-quantitative (RT-q) PCR was performed in certain patients of the experimental group. Biochemical and hematologic parameters, as well as adverse effects, were also evaluated in the experimental group. The experimental treatment decreased the risk of hospitalization by 89% [adjusted relative risk (RR)=0.11, 95% confidence interval (CI): 0.03-0.37, P<0.001] and the risk of death by 96% (adjusted RR=0.04, 95% CI: 0.01-0.42, P=0.007) and also resulted in an 18-fold higher probability of achieving an acceptable symptom state on day 5 (adjusted RR=18.14, 95% CI: 7.29-45.09, P<0.001), compared with usual medical care alone. Overall, neutral electrolyzed saline solution was better than usual medical care alone. Of the patients analyzed, >50% were negative for the virus as detected by RT-qPCR in naso/oro-pharyngeal samples on day 4, with only a small number of positive patients on day 6. Clinical improvement correlated with a decrease in C-reactive protein, aberrant monocytes and increased lymphocytes and platelets. Cortisol and testosterone levels were also evaluated and a decrease in cortisol levels and an increase in the testosterone-cortisol ratio were observed on days 2 and 4. The experimental treatment produced no serious adverse effects. In conclusion, neutral electrolyzed saline solution markedly reduced the symptomatology and risk of progression in ambulatory patients with COVID-19. The present clinical trial was registered in the Cuban public registry of clinical trials (RPCEC) database (May 5, 2020; no. TX-COVID19: RPCEC00000309).

Key Signaling Pathways Regulate the Development and Survival of Auditory Hair Cells.

The loss of auditory sensory hair cells (HCs) is the most common cause of sensorineural hearing loss (SNHL). As the main sound transmission structure in the cochlea, it is necessary to maintain the normal shape and survival of HCs. In this review, we described and summarized the signaling pathways that regulate the development and survival of auditory HCs in SNHL. The role of the mitogen-activated protein kinase (MAPK), phosphoinositide-3 kinase/protein kinase B (PI3K/Akt), Notch/Wnt/Atoh1, calcium channels, and oxidative stress/reactive oxygen species (ROS) signaling pathways are the most relevant. The molecular interactions of these signaling pathways play an important role in the survival of HCs, which may provide a theoretical basis and possible therapeutic interventions for the treatment of hearing loss.

Performance Analysis of TiO2-Modified Co/MgAl2O4 Catalyst for Dry Reforming of Methane in a Fixed Bed Reactor for Syngas (H2, CO) Production

Co/TiO2–MgAl2O4 was investigated in a fixed bed reactor for the dry reforming of methane (DRM) process. Co/TiO2–MgAl2O4 was prepared by modified co-precipitation, followed by the hydrothermal method. The active metal Co was loaded via the wetness impregnation method. The prepared catalyst was characterized by XRD, SEM, TGA, and FTIR. The performance of Co/TiO2–MgAl2O4 for the DRM process was investigated in a reactor with a temperature of 750 °C, a feed ratio (CO2/CH4) of 1, a catalyst loading of 0.5 g, and a feed flow rate of 20 mL min−1. The effect of support interaction with metal and the composite were studied for catalytic activity, the composite showing significantly improved results. Moreover, among the tested Co loadings, 5 wt% Co over the TiO2–MgAl2O4 composite shows the best catalytic performance. The 5%Co/TiO2–MgAl2O4 improved the CH4 and CO2 conversion by up to 70% and 80%, respectively, while the selectivity of H2 and CO improved to 43% and 46.5%, respectively. The achieved H2/CO ratio of 0.9 was due to the excess amount of CO produced because of the higher conversion rate of CO2 and the surface carbon reaction with oxygen species. Furthermore, in a time on stream (TOS) test, the catalyst exhibited 75 h of stability with significant catalytic activity. Catalyst potential lies in catalyst stability and performance results, thus encouraging the further investigation and use of the catalyst for the long-run DRM process.

MO1048PHYTOTHERAPY ON RENAL HYPOXIA: THE PREVENTIVE EFFECTS OF HYDROXYTYROSOL - PRELIMINARY IN VITRO RESULTS

Abstract Background and Aims Renal hypoxia plays a key role in the pathophysiology of acute kidney injury and in the progression of chronic kidney disease, potentiating other important risk factors for renal disease, such as oxidative stress, renal fibrosis, and inflammation. Hydroxytyrosol (HT) is a phenolic compound extracted from olives and olive-derived products, that has been shown to detain potent in vitro antioxidant and anti-inflammatory activity. The aim of this study was to evaluate the preventive therapeutic potential of HT on a cellular model of renal hypoxia. Method A cell line of normal adult proximal tubular epithelium (HK-2 cell line) was used to determine the effects of the chemical induction of hypoxia with cobalt chloride (CoCl2), as well as the preventive potential of HT on the elicited effects. For this purpose, HK-2 cells were exposed for 24 h to 254 µM CoCl2, to mimic the hypoxic conditions, or pre-incubated for 1 h with 5 µM HT and further exposed to the CoCl2 for 24 h more. Cell viability was assessed by the thiazolyl blue tetrazolium bromide reduction assay. Oxidative status was evaluated by the measurement of reactive oxygen and nitrogen species (ROS and RNS) and reduced glutathione (GSH) levels, by using standardized fluorometric and colorimetric assays. The expression of several genes related to the hypoxic, inflammatory, and fibrotic responses was determined by quantitative polymerase chain reaction (PCR). Results CoCl2-exposed HK-2 cells (hypoxic conditions) showed a significant decrease in cell viability (p &amp;lt; 0.0001 vs. control), and a disruption of the oxidative status, characterized by an increase of ROS and RNS production of about 6-fold over control cells (p &amp;lt; 0.0001) and a decrease in GSH intracellular levels of nearly 50 % (p &amp;lt; 0.05). Although the pre-exposure to HT showed no significant effects on the loss of cell viability elicited by CoCl2, the presence of HT prior to induction of hypoxia reduced the generation of ROS and RNS (p &amp;lt; 0.05 for HT + CoCl2 vs. CoCl2) and prevented the GSH depletion (GSH levels for HT + CoCl2 were similar to those of control) elicited by CoCl2. When compared to control cells, CoCl2-exposed HK-2 cells also showed increased expression of genes related to hypoxia (HIF1A, p &amp;lt; 0.05; GAPDH, p &amp;lt; 0.0001), as well as of modulators of inflammation (IL6, p &amp;lt; 0.0001) and fibrosis (TGFB1, p &amp;lt; 0.05). Importantly, the expression of these genes was partially or even totally suppressed by the pre-exposure of cells to HT (GAPDH, p &amp;lt; 0.01 for HT + CoCl2 vs. CoCl2; expression of HIF1A, IL6 and TGFB1 for HT + CoCl2 was similar to that of control). Conclusion Our data supports the potential for a multiplicity of preventive effects of HT, providing antioxidant, anti-inflammatory and anti-fibrotic defenses to renal cells under hypoxic conditions. Importantly, the development of safe and effective therapeutic approaches based on phytochemicals such as HT, may present substantial advantages for renal patients over synthetic drugs, including fewer side effects, significantly lower price, and ease of administration in the form of dietary supplements. Acknowledgments This work was supported by Applied Molecular Biosciences Unit (UCIBIO), financed by national funds from FCT/MCTES (UIDB/04378/2020), by North Portugal Regional Coordination and Development Commission (CCDR-N)/NORTE2020/Portugal 2020 (Norte-01-0145-FEDER-000024), and co-financed by FCT/MCTES (PTDC/OCE-ETA/32492/2017) and FEDER/COMPETE 2020 (POCI-01-0145-FEDER-032492).

MO008NEPHROTOXIC MECHANISMS OF GADOLINIUM: IMPLICATIONS FOR THE USE OF GADOLINIUM-BASED CONSTRAST AGENTS

Abstract Background and Aims Gadolinium-based contrast agents are widely used for magnetic resonance imaging, and although they may be considered well tolerated at recommended dosing levels, recent evidences support the deposition of free gadolinium in the tissues, and its slow release into circulation, resulting in long-term toxicity, which is aggravated in renal patients. The kidney, as the major excretion organ of these agents, and particularly the proximal tubule, as a common location of xenobiotics’ bioaccumulation, may be key targets of gadolinium’s deleterious effects. This study aimed at unveiling the nephrotoxic potential and the underlying mechanisms of toxicity of gadolinium, using an in vitro model of normal human proximal tubular cells (HK-2 cell line). Method HK-2 cells were exposed for 24 h to a wide concentration range of gadolinium, in the form of trichloride hexahydrate, and cell viability was assessed to estimate the half maximal effective concentration (EC50) and the subtoxic concentration eliciting 1 % of cell death (EC01). These ECs were further used to determine the effects of gadolinium on the cell’s oxidative status, mitochondrial function, cell death mechanisms and lipid deposition, through variable colorimetric and fluorometric assays. Expression of the pro-inflammatory gene IL6 was also determined through quantitative PCR. Results Gadolinium induced cell death in a concentration-dependent manner, with estimated EC01 and EC50 of 3 and 340 µM, respectively. When compared to control cells, the subtoxic concentration showed no significant effects in terms of reactive oxygen and nitrogen species (ROS and RNS) production, total glutathione levels (tGSH) or total antioxidant status (TAS). On the other hand, the EC50 showed significant disruption of the oxidative status of the cell, with over 60 % depletion of tGSH cell contents (p &amp;lt; 0.01) and a significant decrease of TAS (p &amp;lt; 0.05). However, this effect was not accompanied by an increase, but rather by a significant decline in ROS and RNS production of about 50 % below control (p &amp;lt; 0.0001). At the EC50, but not at EC01, it was also observed the disturbance of the mitochondrial and energetic homeostasis, as showed by the increment of intracellular free calcium levels, hyperpolarization of the mitochondrial membrane, and decay of the ATP levels (p &amp;lt; 0.0001). Cell death induced by gadolinium was characterized by typical morphological changes of late apoptosis and necrosis, with a significant increase in propidium iodide uptake and lactate dehydrogenase leakage (p ≤ 0.0001) at EC50. The presence of neutral lipids-containing vesicles was observed in the cytoplasm of cells exposed to gadolinium using the fluorescent dye BODIPY, already noticeable at the subtoxic concentration. Cells exposed to gadolinium also showed increased expression of IL6, though this effect was only significant at the EC01 (p &amp;lt; 0.05). Conclusion Gadolinium showed marked cytotoxic potential at micromolar levels in HK-2 cells. This cytotoxicity was characterized by increased oxidative stress independent of ROS and RNS production and mitochondrial dysfunction followed by cell death via late apoptosis and necrosis. At a subtoxic concentration, gadolinium was also able to elicit the accumulation of lipidic vesicles within the cells’ cytoplasm, and to trigger a pro-inflammatory response. Although it is still unclear which amount of gadolinium is in fact released from the complexes commonly used as contrast agents, this study shows that gadolinium ion has direct nephrotoxic potential, with noteworthy manifestations at subtoxic concentrations. Acknowledgments This work was supported by Applied Molecular Biosciences Unit (UCIBIO), financed by national funds from FCT/MCTES (UIDB/04378/2020), by North Portugal Regional Coordination and Development Commission (CCDR-N)/NORTE2020/Portugal 2020 (Norte-01-0145-FEDER-000024).

Effects of Moringa Extract on Aminoglycoside-Induced Hair Cell Death and Organ of Corti Damage.

Moringa extract, a naturally occurring anti-oxidant, protects against aminoglycoside-induced hair cell death and hearing loss within the organ of Corti. Reactive oxygen species (ROS) arise primarily in the mitochondria and have been implicated in aminoglycoside-induced ototoxicity. Mitochondrial dysfunction results in loss of membrane potential, release of caspases, and cell apoptosis. Moringa extract has not previously been examined as a protective agent for aminoglycoside-induced ototoxicity. Putative otoprotective effects of moringa extract were investigated in an organotypic model using murine organ of Corti explants subjected to gentamicin-induced ototoxicity. Assays evaluated hair cell loss, cytochrome oxidase expression, mitochondrial membrane potential integrity, and caspase activity. In vitro application of moringa conferred significant protection from gentamicin-induced hair cell loss at dosages from 25 to 300 μg/mL, with dosages above 100 μg/mL conferring near complete protection. Assays demonstrated moringa extract suppression of ROS, preservation of cytochrome oxidase activity, and reduction in caspase production. Moringa extract demonstrated potent antioxidant properties with significant protection against gentamicin ototoxicity in cochlear explants.

Lipoxin A4 activates ALX/FPR2 to attenuate inflammation in Aspergillus fumigatus keratitis

PurposeTo explore the anti-inflammatory effect of lipoxin A4 (LXA4) in Aspergillus fumigatus (A. fumigatus) keratitis and the underlying mechanisms. MethodsIn A. fumigatus keratitis mouse models, enzyme-linked immunosorbent assay (ELISA) was used to detect the level of LXA4. Clinical scores were utilized to evaluate fungal keratitis (FK) severity. Fungal load was assessed by plate count. Immunofluorescence staining, HE staining and myeloperoxidase (MPO) assays were carried out to evaluate the neutrophil infiltration and activity. In A. fumigatus infected mouse corneas and inactivated A. fumigatus-stimulated RAW264.7 cells, quantitative real time polymerase chain reaction (qRT-PCR) and ELISA were applied to assess the expression of pro-inflammatory mediators and anti-inflammatory factors.Reactive oxygen species (ROS) was determined by 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) staining in RAW264.7 cells. ResultsLXA4 level was significantly increased in mice with A. fumigatus keratitis. In an A. fumigatus keratitis mouse model, LXA4 treatment alleviated FK severity, reduced fungal load and repressed neutrophil infiltration and activity. Additionally, LXA4 inhibited the expression of pro-inflammatory mediators including IL-1β, TNF-α, IL-6, cyclooxygenase-2 (COX-2), TLR-2, TLR-4, Dectin-1 and iNOS, and promoted the expression of anti-inflammatory factors IL-10 and Arg-1. In RAW264.7 cells, LXA4 receptor/formyl peptide receptor 2 (ALX/FPR2) blockade reversed the anti-inflammatory effect of LXA4. LXA4 suppressed inactivated A. fumigatus induced elevated ROS production in RAW264.7 cells, which was abrogated by ALX/FPR2 antagonist Boc-2. ConclusionLXA4 ameliorated inflammatory response by suppressing neutrophil infiltration, downregulating the expression of pro-inflammatory mediators and ROS production through ALX/FPR2 receptor in A. fumigatus keratitis.

One-pot in situ synthesis of Cu-SAPO-34/SiC catalytic membrane with enhanced binding strength and chemical resistance for combined removal of NO and dust

The SiC catalytic membrane combining dust removal and denitration can realize the efficacious treatment of atmospheric pollutants. Unfortunately, a large amount of SiO2, formed by the partial oxidation of SiC at a high temperature, results in the decreased chemical resistance of SiC catalytic membrane. In addition, the complicated preparation processes and susceptible to loss of catalytic components under harsh conditions restrict the industrial application of SiC catalytic membranes. Here, the Cu-SAPO-34(D)/SiC catalytic membranes were directly prepared via a facile one-pot hydrothermal synthesis method, which ingeniously utilized the generated SiO2 as a Si source to participate in the growth of Cu-SAPO-34 zeolites. Excellent binding strength and chemical resistance were simultaneously realized for the SiC catalytic membranes. As a comparison, a Cu-SAPO-34(I)/SiC catalytic membrane was fabricated via the conventional two-step ion-exchange method. The 0.2 Cu-SAPO-34(D)/SiC (Cu molar ratio of 0.2) achieved the best NH3-SCR performance among the prepared catalytic membranes for its highly active copper and oxygen species, abundant Lewis acid sites and remarkable redox capacity. When implementing the simultaneous removal of NO and PM, the 0.2 Cu-SAPO-34(D)/SiC catalytic membrane achieved a high NO degradation performance of 98% from 200 to 280 °C, coupled with an excellent PM0.3 (model dust with average size of 300 nm) filtration performance of 99.99%. These results were better than those of the Cu-SAPO-34(I)/SiC catalytic membrane (92% for NO degradation and 99.98% for PM0.3 filtration). The one-pot in situ synthesis of Cu-SAPO-34(D)/SiC catalytic membrane with enhanced binding strength and chemical resistance provides a novel strategy for preparation of high-performance SiC catalytic membrane with double benefits.

The Influence of Archaeometallurgical Copper Alloy Castings Microstructure towards Corrosion Evolution in Various Corrosive Media

The local patterns at the interfaces of corrosion stratification, developed on two archaeometallurgical bronzes (a Cu-Sn-Pb and a Cu-Zn-Sn-Pb alloy), in the as-cast condition, were assessed by OM and SEM-EDS systematic elemental chemical analyses. Previously, the alloys—whose metallurgical features and electrochemical behaviour were already well studied—have been subjected to laboratory corrosion experiments. The corrosion procedures involved electrochemical anodic polarization experiments in various chloride media: 0.1 mol/L NaCl, 0.6 mol/L NaCl and two other synthetic chloride-containing solutions, representing electrolytes present in marine urban atmosphere and in the soil of coastal sites. The characterization of the Cu-Sn-Pb alloy electrochemical patinas after anodic sweep (OCP+ 0.6 V) revealed that the metal in all electrolytes undergoes extensive chloride attack and selective dissolution of copper which initiates from the dendritic areas acting as anodic sites. The most abundant corrosion products identified by FTIR in all electrochemical patinas were Cu2(OH)3Cl), Cu2(OH)2CO3 and amorphous Cu and Sn oxides. The characterization of the Cu-Sn-Pb alloy electrochemical patina after slow anodic sweep (OCP+ 1.5 V) in 0.1 mol/L NaCl reveals selective oxidation of dendrites and higher decuprification rate in these areas. Corrosion products of Sn-rich interdendritic areas are dominated by oxygen species (oxides, hydroxides, hydroxyoxides) and Cu-rich dendrites by chlorides. In the case of Cu-Zn-Sn-Pb, Zn in dendritic areas is preferentially attacked. The alloy undergoes simultaneous dezincification and decuprification, with the former progressing faster, especially in dendritic areas. The two processes at the alloy/patina interface leave behind a metal surface where α-dendrites are enriched in Sn compared to the alloy matrix. The results of this study highlight the dynamic profile of corrosion layer build-up in bronze and brass. Moreover, the perception of the dealloying mechanisms progression on casting features, at mid-term corrosion stages, is extended.

Iodine local environment in high pressure borosilicate glasses: An X-ray photoelectron spectroscopy and X-ray absorption spectroscopy investigation

• Iodine is dissolved as iodide (I − ) in high pressure borosilicate glasses. • Both alkali and alkaline-earth cations act as a charge compensator to I − species. • The absence of iodate (I 5+ ) suggests that there is a complex interplay between I − species and oxygen species within the glass structure. The 129 I radioactive isotope is a by-product of nuclear plants activity. Owing to its strong volatility, there is currently no ideal protocol to immobilize 129 I in nuclear waste borosilicate glasses. Recently, we have proposed the use of high-pressure syntheses to dissolve iodine in various glass compositions; however, I speciation and dissolution mechanism could not be determined. We have adopted an approach combining X-ray Photoelectron Spectroscopy (XPS) and X-ray Absorption Spectroscopy (XAS) methods to determine I speciation and molecular environment in glasses containing from 0.5 to 2.5 mol.% I. The XPS spectra reveal that I is mostly dissolved as iodide (>85% I − ) with a small proportion of elemental iodine (<15% I 0 ) and the absence of iodate species (I 5+ ). For borosilicate glasses, the XAS results and subsequent spectrum simulations suggested that Na and Ca are involved in the I − vicinity with averaged derived coordination number (CN) of 3.6 and 2.0 and bond length to the nearest neighbour (r X-I ) 2.98 and 2.85 Å, respectively. These results suggest that the coexistence of both I − and I 5+ species is not requested for electric neutrality but instead, we explain the I speciation by the possible interplay with oxygen species from the borosilicate matrix. In addition, the results imply that the borosilicate network is affected by the I dissolution.

Antibacterial properties of phenothiazine derivatives against multidrug-resistant Acinetobacter baumannii strains.

As options to treat recalcitrant bacterial infections which are increasingly limited due to multidrug-resistant strains, searching for new, effective antibacterial compounds is necessary. One strategy is to generate treatment alternatives by drug repurposing. In this work, phenotypic microarrays were used for the screening of miscellaneous compounds against the growth and biofilm formation of Acinetobacter baumannii, an important emergent multidrug-resistant opportunistic pathogen. The results showed that the phenothiazine derivatives, such as promethazine, trifluoperazine, thioridazine, and chlorpromazine, inhibited the growth of antibiotic-sensitive and multidrug-resistant strains (showing minimal inhibitory concentrations ranging from 0·05 to 0·6gl-1 and minimal bactericidal concentrations ranging from 0·1 to 2·5gl-1 ). All phenothiazine derivatives were active against biofilm cells (with minimal biofilm eradication concentrations ranging from 0·5 to >3gl-1 ). Chlorpromazine promoted reactive oxigen species (ROS) production, and cell membrane and DNA damage. Chlorpromazine showed synergy with antibiotics such as ceftazidime, meropenem, and colistin and was an effective treatment for experimentally infected Galleria mellonella when combined with ceftazidime. It was demonstrated that phenothiazine derivatives, especially chlorpromazine, are drugs with attractive antibacterial properties against nosocomial MDR strains of A. baumannii, by generating ROS and cell membrane and DNA damage. The present study indicates that repurposing phenothiazine derivatives for treating recalcitrant infections by A. baumannii could be promising.

Transport properties of imidazolium based ionic liquid electrolytes from molecular dynamics simulations

AbstractIonic liquids (ILs) are promising electrolytes for high‐performance Li‐ion batteries (LIBs), which can significantly improve the safety and energy storage capacity. Although extensive experimental and computational studies have reported, further exploration is needed to understand the properties of IL systems, their microscopic structures and dynamics, and the behavior of Li ions in ILs. We report here results of molecular dynamics simulations as a function of electric field for Li diffusion in two IL systems, [EMIM][TFSI] and [BMIM][TFSI] doped with various concentrations of LiTFSI. We find that the migration of each individual Li ion depends largely on its micro‐environment, leading to differences by factors of up to 100 in the diffusivity. The structural and dynamical properties indicate that Li diffusion is affected significantly by the coordination and interaction with the oxygen species in the TFSI anions. Moreover, the IL cations also contribute to the Li diffusion mechanism by attenuating the Li–TFSI interaction.

Biomass wood-derived efficient Fe–N–C catalysts for oxygen reduction reaction

Efficient and low-cost electrocatalysts for oxygen reduction reaction (ORR) were the key for scalable application of metal–air batteries and fuel cells. Herein, iron-based nitrogen-doped carbon catalysts (Fe–N–Cwood) were prepared, using hydrothermal-pyrolysis-treated wood-derived nitrogen-doped carbon as the support. This support possessed large specific surface area and macro–meso–micro hierarchical porous networks, ensuring fluent mass transfer of electrolyte and oxygen species. In the ORR electrochemical test, Fe–N–Cwood catalyst showed an excellent activity, with a half-wave potential of 0.90 V in 0.1 M KOH, and a half-wave potential of 0.70 V in 0.1 M HClO4. Moreover, durability tests illustrated that Fe–N–Cwood possessed high stability and methanol tolerance. The Fe–N–Cwood-based Zn–air battery delivered a peak power density of 231 mW cm−2, suggesting its potential applications in sustainable energy conversion systems. A highly efficient ORR electrocatalyst was obtained by embedding iron nanoparticles with hydrothermal-pyrolysis-treated wood-derived carbon.

Potential dependent Ag nanoparticle electrodeposition on Vulcan XC-72R carbon support for alkaline oxygen reduction reaction

Abstract Carbon-supported Ag nanocatalysts, synthesized at five different electrodeposition potentials ranging from 0.0 to 0.4 V vs. RHE, were successfully prepared by using the rotating disk slurry electrode (RoDSE) technique. This was done to determine the ideal electrodeposition parameters that facilitate optimal metal loading and particle dispersion for an efficient oxygen reduction reaction (ORR) through the 4-e- pathway. In this study, the potentials were chosen based on different regions of Ag electrodeposition on a clean glassy carbon electrode. Each Ag/Vulcan catalyst was characterized using different techniques including TEM, XRD, ICP-OES, XPS, and Raman spectroscopy. These techniques confirmed the presence of Ag on the carbon support and determined that the applied potential affected the Ag oxidation state and catalytic ORR activity. Herein, we show that as the electrodeposition potential increases, we observe a lower electrodeposition current. This suggests gentle Ag deposition on the carbon support, resulting in reduced agglomeration. We confirm that the deposition potential of the Ag has a direct effect on the electrocatalytic behavior of the Ag/C catalyst. Ag crystallinity was determined using XRD, which showed a particle size in the range of 1 to 35 nm for each potential. ORR studies were conducted in O2 saturated 0.1 M KOH solution using the rotating disk electrode (RDE) technique and cyclic voltammetry. The oxygen species at the Ag NPs surface suggest a synergistic effect in the ORR mechanism. Finally, among the five studied electrodeposition potentials of Ag, 0.1 V vs. RHE provided the optimal conditions to generate Ag catalysts with low agglomeration, small particle size, high ORR mass activity, and electron transfer equal to 3.5 in 0.1 M KOH electrolyte.