Prediction of Isoelectric Point of Manganese and Cobalt Lamellar Oxides: Application to Controlled Synthesis of Mixed Oxides.

PubMed

Tang, Céline; Giaume, Domitille; Guerlou-Demourgues, Liliane; Lefèvre, Grégory; Barboux, Philippe

2018-05-30

To design novel layered materials, bottom-up strategy is very promising. It consists of (1) synthesizing various layered oxides, (2) exfoliating them, then (3) restacking them in a controlled way. The last step is based on electrostatic interactions between different layered oxides and is difficult to control. The aim of this study is to facilitate this step by predicting the isoelectric point (IEP) of exfoliated materials. The Multisite Complexation model (MUSIC) was used for this objective and was shown to be able to predict IEP from the mean oxidation state of the metal in the (hydr)oxides, as the main parameter. Moreover, the effect of exfoliation on IEP has also been calculated. Starting from platelets with a high basal surface area over total surface area, we show that the exfoliation process has no impact on calculated IEP value, as verified with experiments. Moreover, the restacked materials containing different monometallic (hydr)oxide layers also have an IEP consistent with values calculated with the model. This study proves that MUSIC model is a useful tool to predict IEP of various complex metal oxides and hydroxides.

Inhibition of neuronal nitric oxide synthase in ovine model of acute lung injury*

PubMed Central

Enkhbaatar, Perenlei; Connelly, Rhykka; Wang, Jianpu; Nakano, Yoshimitsu; Lange, Matthias; Hamahata, Atsumori; Horvath, Eszter; Szabo, Csaba; Jaroch, Stefan; Hölscher, Peter; Hillmann, Margrit; Traber, Lillian D.; Schmalstieg, Frank C.; Herndon, David N.; Traber, Daniel L.

2013-01-01

Objective Acute respiratory distress syndrome/acute lung injury is a serious complication of burn patients with concomitant smoke inhalation injury. Nitric oxide has been shown to play a major role in pulmonary dysfunction from thermal damage. In this study, we have tested the hypothesis that inhibition of neuronal nitric oxide synthase could ameliorate the severity of acute lung injury using our well-established ovine model of cutaneous burn and smoke inhalation. Design Prospective, randomized, controlled, experimental animals study. Setting Investigational intensive care unit at university hospital. Subjects Adult female sheep Interventions Female sheep (n = 16) were surgically prepared for the study. Seven days after surgery, all sheep were randomly allocated into three study groups: sham (noninjured, nontreated, n = 6); control (injured, treated with saline, n = 6); and neuronal nitric oxide synthase (injured, treated with specific neuronal nitric oxide synthase inhibitor, ZK 234238 (n = 4). Control and neuronal nitric oxide synthase groups were given a cutaneous burn (40% of total body surface, third degree) and insufflated with cotton smoke (48 breaths, <40°C) under halothane anesthesia. Animals in sham group received fake injury also under halothane anesthesia. After injury or fake injury procedure, all sheep were placed on ventilators and resuscitated with lactated Ringer's solution. Neuronal nitric oxide synthase group was administered with continuous infusion of ZK 234238 started 1 hr postinjury with a dose of 100 μg/kg/hr. Sham and control groups received same amount of saline. Measurements and Main Results Cardiopulmonary hemodynamics monitored during the 24-hr experimental time period was stable in the sham group. Control sheep developed multiple signs of acute lung injury. This pathophysiology included decreased pulmonary gas exchange and lung compliance, increased pulmonary edema, and inflammatory indices, such as interleukin-8. Treatment of injured sheep with neuronal nitric oxide synthase inhibitor attenuated all the observed pulmonary pathophysiology. Conclusions The results provide definitive evidence that inhibition of neuronal nitric oxide synthase-derived excessive nitric oxide may be a novel and beneficial treatment strategy for pulmonary pathology in burn victims with smoke inhalation injury. PMID:19050603

Implantation of Neural Probes in the Brain Elicits Oxidative Stress

PubMed Central

Ereifej, Evon S.; Rial, Griffin M.; Hermann, John K.; Smith, Cara S.; Meade, Seth M.; Rayyan, Jacob M.; Chen, Keying; Feng, He; Capadona, Jeffrey R.

2018-01-01

Clinical implantation of intracortical microelectrodes has been hindered, at least in part, by the perpetual inflammatory response occurring after device implantation. The neuroinflammatory response observed after device implantation has been correlated to oxidative stress that occurs due to neurological injury and disease. However, there has yet to be a definitive link of oxidative stress to intracortical microelectrode implantation. Thus, the objective of this study is to give direct evidence of oxidative stress following intracortical microelectrode implantation. This study also aims to identify potential molecular targets to attenuate oxidative stress observed postimplantation. Here, we implanted adult rats with silicon non-functional microelectrode probes for 4 weeks and compared the oxidative stress response to no surgery controls through postmortem gene expression analysis and qualitative histological observation of oxidative stress markers. Gene expression analysis results at 4 weeks postimplantation indicated that EH domain-containing 2, prion protein gene (Prnp), and Stearoyl-Coenzyme A desaturase 1 (Scd1) were all significantly higher for animals implanted with intracortical microelectrode probes compared to no surgery control animals. To the contrary, NADPH oxidase activator 1 (Noxa1) relative gene expression was significantly lower for implanted animals compared to no surgery control animals. Histological observation of oxidative stress showed an increased expression of oxidized proteins, lipids, and nucleic acids concentrated around the implant site. Collectively, our results reveal there is a presence of oxidative stress following intracortical microelectrode implantation compared to no surgery controls. Further investigation targeting these specific oxidative stress linked genes could be beneficial to understanding potential mechanisms and downstream therapeutics that can be utilized to reduce oxidative stress-mediated damage following microelectrode implantation. PMID:29487848

Influence of glycemic control on some real-time biomarkers of free radical formation in type 2 diabetic patients: An EPR study.

PubMed

Gadjeva, Veselina Georgieva; Goycheva, Petia; Nikolova, Galina; Zheleva, Antoaneta

2017-11-01

The pathology of diabetes is associated with several mechanisms, one of which is oxidative stress (OS). The relationship between OS and diabetic complications has been extensively investigated. OS has been suggested to be involved in the genesis of both macroand microangiopathy. In contrast, the relationship between OS and insulin action is a neglected research area. The aim of this study is to elucidate the effect of glycemic control in type 2 diabetic patients by following the serum levels of some real-time oxidative stress biomarkers. The study group consisted of 53 type 2 diabetic patients (31 with poor glycemic control and 22 with good glycemic control) and 24 healthy control subjects. The oxidative stress biomarkers (ROS, Asc• and •NO) were measured by using electron paramagnetic resonance spectroscopy (EPR) methods and compared with clinical parameters. The statistically significantly higher levels of ROS products and •NO in type 2 diabetic patients in both groups compared to controls mean that the oxidation processes take place at the time the survey is performed. Free radical overproduction persists after the normalization of the glucose levels, and oxidative stress may be involved in the "metabolic memory" effect. This is confirmed by the positive correlation between ROS levels/•NO and average blood glucose levels, triglycerides, and total cholesterol. Furthermore, the low level of the ascorbate radical in both diabetes groups compared to controls confirmed an increase in oxidation processes. Higher levels of real-time biomarkers show that intensive insulin treatment does not lead to the expected decrease in oxidative processes involving ROS and •NO, probably due to "metabolic memory".

Comparative studies on the effects of clinically used anticonvulsants on the oxidative stress biomarkers in pentylenetetrazole-induced kindling model of epileptogenesis in mice.

PubMed

Mazhar, Faizan; Malhi, Saima M; Simjee, Shabana U

2017-01-01

Oxidative stress plays a key role in the pathogenesis of epilepsy and contributes in underlying epileptogenesis process. Anticonvulsant drugs targeting the oxidative stress domain of epileptogenesis may provide better control of seizure. The present study was carried out to investigate the effect of clinically used anti-epileptic drugs (AEDs) on the course of pentylenetetrazole (PTZ)-induced kindling and oxidative stress markers in mice. Six mechanistically heterogeneous anticonvulsants: phenobarbital, phenytoin, levetiracetam, pregabalin, topiramate, and felbamate were selected and their redox profiles were determined. Diazepam was used as a drug control for comparison. Kindling was induced by repeated injections of a sub-convulsive dose of PTZ (50 mg/kg, s.c.) on alternate days until seizure score 5 was evoked in the control kindled group. Anticonvulsants were administered daily. Following PTZ kindling, oxidative stress biomarkers were assessed in homogenized whole brain samples and estimated for the levels of nitric oxide, peroxide, malondialdehyde, protein carbonyl, reduced glutathione, and activities of nitric oxide synthase and superoxide dismutase. Biochemical analysis revealed a significant increase in the levels of reactive oxygen species with a parallel decrease in endogenous anti-oxidants in PTZ-kindled control animals. Daily treatment with levetiracetam and felbamate significantly decreased the PTZ-induced seizure score as well as the levels of nitric oxide (p<0.001), nitric oxide synthase activity (p<0.05), peroxide levels (p<0.05), and malondialdehyde (p<0.05). Levetiracetam and felbamate significantly decreased lipid and protein peroxidation whereas topiramate was found to reduce lipid peroxidation only. An AED that produces anticonvulsant effect by the diversified mechanism of action such as levetiracetam, felbamate, and topiramate exhibited superior anti-oxidative stress activity in addition to their anticonvulsant activity.

Oxygen Diffusion and Reaction Kinetics in Continuous Fiber Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Halbig, Michael C.; Eckel, Andrew J.; Cawley, James D.

1999-01-01

Previous stressed oxidation tests of C/SiC composites at elevated temperatures (350 C to 1500 C) and sustained stresses (69 MPa and 172 MPa) have led to the development of a finite difference cracked matrix model. The times to failure in the samples suggest oxidation occurred in two kinetic regimes defined by the rate controlling mechanisms (i.e. diffusion controlled and reaction controlled kinetics). Microstructural analysis revealed preferential oxidation along as-fabricated, matrix microcracks and also suggested two regimes of oxidation kinetics dependent on the oxidation temperature. Based on experimental results, observation, and theory, a finite difference model was developed. The model simulates the diffusion of oxygen into a matrix crack bridged by carbon fibers. The model facilitates the study of the relative importance of temperature, the reaction rate constant, and the diffusion coefficient on the overall oxidation kinetics.

Evaluation of Oxidant/Antioxidant Status and Cytokine Levels in Patients with Cannabis Use Disorder.

PubMed

Bayazit, Huseyin; Selek, Salih; Karababa, Ibrahim Fatih; Cicek, Erdinc; Aksoy, Nurten

2017-08-31

Cannabis is the most commonly used illegal drug in the world and it has several adverse effects such as anxiety, panic reactions and psychotic symptoms. In this study, we aimed to evaluate oxidant, anti-oxidant status and cytokine levels in individuals with cannabis use disorder. Thirty-four patients with cannabis use disorder and 34 healthy controls were enrolled to the study. Serum total antioxidant status, total oxidant status and cytokine levels were investigated in patients with cannabis use disorder and healthy controls. We found increased levels of total oxidant status, oxidative stress index and interleukin (IL) 1β, IL-6, IL-8, and tumor necrosis factor (TNF) α in individuals with cannabis dependency compared to healthy people. When we compared total antioxidant status, IL-12, and interferon (IFN) γ levels, there were no differences in both groups. There was positive correlation between IL-6 and total oxidant status, oxidative stress index levels. The oxidative balance of individuals with cannabis use disorder was impaired and they had higher levels of IL-1β, IL-6, IL-8, and TNF-α, which is a pro-inflammatory cytokine and indicates increased inflammation compared to healthy controls. Thus, these findings suggest that cannabis increased inflammation and impaired the oxidative balance.

Simple Copper Catalysts for the Aerobic Oxidation of Amines: Selectivity Control by the Counterion.

PubMed

Xu, Boran; Hartigan, Elizabeth M; Feula, Giancarlo; Huang, Zheng; Lumb, Jean-Philip; Arndtsen, Bruce A

2016-12-19

We describe the use of simple copper-salt catalysts in the selective aerobic oxidation of amines to nitriles or imines. These catalysts are marked by their exceptional efficiency, operate at ambient temperature and pressure, and allow the oxidation of amines without expensive ligands or additives. This study highlights the significant role counterions can play in controlling selectivity in catalytic aerobic oxidations. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of oxidant and antioxidant status in infants with hyperbilirubinemia and kernicterus.

PubMed

Doğan, Murat; Peker, Erdal; Kirimi, Ercan; Sal, Ertan; Akbayram, Sinan; Erel, Ozcan; Ocak, Ali Riza; Tuncer, Oguz

2011-11-01

The objective of the present study was to determine oxidant and antioxidant status in infants with hyperbilirubinemia and/or kernicterus and to find whether there is a relationship between bilirubin level and oxidant/antioxidant status. The study includes 69 full-term newborns (neonates with hyperbilirubinemia needing phototherapy [Group 1, n = 36] and neonates with kernicterus [Group 2, n = 33]) and 25 age-matched healthy newborn. Plasma total antioxidant capacity (TAC) and serum total oxidant status (TOS) were significantly higher in Groups 1 and 2 than the control group. There was a significant difference between Group 1 and control cases for malondialdehyde (MDA; p < 0.001). Total free sulfhydryl group (TTHI) values were significantly elevated in Group 1 compared to Group 2 and control cases. Correlation analysis showed that the correlation between total bilirubin (TB) and TAC, TOS, MDA and oxidative stress index may be expressed by a quadratic curve. After phototherapy, a statistically significant increase in nitrite level was observed. We demonstrated that the relationship between serum TB and antioxidants and oxidative stress could be expressed by a quadratic correlation curve.

Study of telomere length and different markers of oxidative stress in patients with Parkinson's disease.

PubMed

Watfa, G; Dragonas, C; Brosche, T; Dittrich, R; Sieber, C C; Alecu, C; Benetos, A; Nzietchueng, R

2011-04-01

Many studies have shown that short telomere length (TL) is associated with high oxidative stress and various age-related diseases. Parkinson's disease (PD) is an age-related disease, and although its pathogenic mechanism is uncertain, oxidative stress is believed to be implicated in this pathology. The aim of this case-control study was to assess both TL and the different markers of oxidative stress in elderly patients with PD compared to age control subjects. 20 PD patients and 15 age-matched controls, >65 years were studied. TL was measured by Southern blotting from DNA samples extracted from white blood cells. Superoxide dismutase (SOD) activity and plasma levels of total glutathione and protein carbonyls were determined. There was a trend for lower TL in PD patients: 6.06 ± 0.81 kb in PD versus 6.45 ± 0.73 kb in controls (p = 0.08). No significant difference was found between the two groups in terms of oxidative stress markers. In controls, age was the main determinant of telomere shortening (r = -0.547; p = 0.03) whereas, in PD patients, telomere shortening was mainly dependent on plasmatic concentrations of carbonyl proteins (r= -0.544; p=0.044). In PD patients, a negative association was observed between plasma carbonyl protein levels and SOD activity (r= -0.622, p=0.004). In PD, TL is shorter in presence of high oxidative stress as measured by carbonyl protein levels. The absence of telomere attrition with age among patients with PD could reflect a telomere regulation by mechanisms other than age.

Oxidant-antioxidant balance in the blood of patients with chronic obstructive pulmonary disease after smoking cessation.

PubMed

Woźniak, Alina; Górecki, Dariusz; Szpinda, Michał; Mila-Kierzenkowska, Celestyna; Woźniak, Bartosz

2013-01-01

The effect of smoking cessation on the oxidative stress in patients with chronic obstructive pulmonary disease (COPD) was assessed. We recruited 73 smokers with COPD (study group), whose blood was analysed before smoking cessation, after the 1st, 2nd, and 3rd months of abstinence, 35 healthy nonsmokers (Control I), and 35 smokers with COPD (Control II). Blood was taken once in Control I and 4 times (every month) in Control II. In the study group conjugated dienes (CDs) level in plasma and erythrocytes before smoking cessation was 3 and 6.5 times higher than in Control I, respectively (P < 0.001), while thiobarbituric acid-reactive substances (TBARS) level was 89% (P < 0.001) and 51% higher (P < 0.01), respectively. Superoxide dismutase (SOD) activity was 40% higher (P < 0.05) while glutathione peroxidase (GPx) was 41% lower (P < 0.001) than in Control I. In Control II, the similar differences as compared to Control I were observed throughout the study. Smoking cessation resulted in decrease of CDs, TBARS, and SOD and GPx increase, with no changes in catalase and vitamins A and E. COPD is accompanied by oxidative stress. A three-month tobacco abstinence facilitated restoring the oxidant-antioxidant balance systemically, but it did not affect spirometric parameters.

Increased oxidative/nitrosative stress and decreased antioxidant enzyme activities in prostate cancer.

PubMed

Arsova-Sarafinovska, Zorica; Eken, Ayse; Matevska, Nadica; Erdem, Onur; Sayal, Ahmet; Savaser, Ayhan; Banev, Saso; Petrovski, Daniel; Dzikova, Sonja; Georgiev, Vladimir; Sikole, Aleksandar; Ozgök, Yaşar; Suturkova, Ljubica; Dimovski, Aleksandar J; Aydin, Ahmet

2009-08-01

The study was aimed to evaluate the oxidative/nitrosative stress status in prostate cancer (CaP) and benign prostatic hyperplasia (BPH). 312 men from two different populations were included: 163 men from Macedonia (73 CaP patients, 67 BPH patients and 23 control subjects) and 149 men from Turkey (34 prostate cancer patients, 100 BPH patients and 15 control subjects). We measured erythrocyte malondialdehyde (MDA) levels, erythrocyte activities of superoxide dismutase (CuZn-SOD), glutathione peroxidase (GPX) and catalase (CAT); plasma nitrite/nitrate (NO(2)(-)/NO(3)(-)), cGMP and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels. A similar pattern of alteration in the oxidative/nitrosative stress-related parameters was found in both, Macedonian and Turkish studied samples: higher MDA concentrations with lower GPX and CuZn-SOD activities in CaP patients versus controls and BPH groups. The CAT activity was decreased in the CaP patients versus controls in the Turkish studied sample. Furthermore, CaP patients had increased plasma NO(2)(-)/NO(3)(-) and cGMP levels versus controls and BPH groups in both studied samples. This study has confirmed an imbalance in the oxidative stress/antioxidant status and revealed an altered nitrosative status in prostate cancer patients.

Associations of oxidative stress status parameters with traditional cardiovascular disease risk factors in patients with schizophrenia.

PubMed

Vidović, Bojana; Stefanović, Aleksandra; Milovanović, Srđan; Ðorđević, Brižita; Kotur-Stevuljević, Jelena; Ivanišević, Jasmina; Miljković, Milica; Spasić, Slavica

2014-04-01

The purpose of this study was to assess oxidative stress status parameters and their possible associations with traditional cardiovascular risk factors in patients with schizophrenia, as well as their potential for patient-control discrimination. Fasting glucose, lipid profile and oxidative stress status parameters were assessed in 30 schizophrenic patients with atypical antipsychotic therapy and 60 control subjects. Malondialdehyde (MDA), pro-oxidant/antioxidant balance (PAB) and total anti-oxidant status (TAS) were significantly higher whereas total sulfhydryl (SH) groups were significantly lower in schizophrenic patients vs. control group. Higher serum PAB values showed an independent association with schizophrenia. The addition of PAB to conventional risk factors improved discrimination between healthy control subjects and patients. Increased oxidative stress and changed lipid profile parameters are associated in schizophrenic patients and may indicate risk for atherosclerosis. The serum PAB level may reflect the levels of oxidative stress in schizophrenia and improve discrimination of patients from controls.

Oxidative stress and decreased thiol level in patients with migraine: cross-sectional study.

PubMed

Eren, Yasemin; Dirik, Ebru; Neşelioğlu, Salim; Erel, Özcan

2015-12-01

Although migraine is a neurological disorder known since long, its physiopathology remains unclear. Recent studies suggest that migraine is associated with oxidative stress; however, they report divergent results. The aim of the present study was to evaluate total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), and serum thiol level in migraine patients with or without aura. The study group consisted of 141 migraine patients. The control group included 70 healthy subjects. TAS, TOS, OSI were evaluated using a method developed by Erel. Serum thiol level was measured using the Hu method. No difference was found in TAS, TOS, OSI between the patients and controls. The level of thiol was significantly lower in patients than in controls. Negative correlations were detected between thiol level and Migraine Disability Assessment score in patients. Although TAS, TOS, and OSI were similar to those of the control group, serum thiol level, an important marker of antioxidant capacity, was significantly lower in migraines compared with controls, and caused more serious disability. Novel treatment approaches may be developed based on these data, and compounds containing thiol, such as alpha lipoic acid and N-acetyl cysteine, may be used in prophylaxis.

Oxidative stress parameters in localized scleroderma patients.

PubMed

Kilinc, F; Sener, S; Akbaş, A; Metin, A; Kirbaş, S; Neselioglu, S; Erel, O

2016-11-01

Localized scleroderma (LS) (morphea) is a chronic, inflammatory skin disease with unknown cause that progresses with sclerosis in the skin and/or subcutaneous tissues. Its pathogenesis is not completely understood. Oxidative stress is suggested to have a role in the pathogenesis of localized scleroderma. We have aimed to determine the relationship of morphea lesions with oxidative stress. The total oxidant capacity (TOC), total antioxidant capacity (TAC), paroxonase (PON) and arylesterase (ARES) activity parameters of PON 1 enzyme levels in the serum were investigated in 13 LS patients (generalized and plaque type) and 13 healthy controls. TOC values of the patient group were found higher than the TOC values of the control group (p < 0.01). ARES values of the patient group was found to be higher than the control group (p < 0.0001). OSI was significantly higher in the patient group when compared to the control (p < 0.005). Oxidative stress seems to be effective in the pathogenesis. ARES levels have increased in morphea patients regarding to the oxidative stress and its reduction. Further controlled studies are required in wider series.

Evaluation of salivary oxidate stress biomarkers, nitric oxide and C-reactive protein in patients with oral lichen planus and burning mouth syndrome.

PubMed

Tvarijonaviciute, Asta; Aznar-Cayuela, Cristina; Rubio, Camila P; Ceron, José J; López-Jornet, Pia

2017-05-01

The aim of this study was to evaluate oxidative stress factors and C-reactive protein in the saliva of patients with oral lichen planus (OLP) and burning mouth syndrome (BMS). This consecutive, cross-sectional study included 20 patients with OLP, 19 with burning mouth syndrome (BMS), and 31 control subjects. The oral cavity of each patient was examined and patients responded to a quality of life questionnaire (OHIP-14) and the xerostomia inventory. The following parameters were measured in whole non-stimulated saliva: trolox equivalent antioxidant capacity (TEAC); total antioxidant capacity (TAC); cupric reducing antioxidant capacity (CUPRAC); ferric reducing ability of plasma (FRAP); C-reactive protein (CRP); nitric oxide; nitrates; and nitrites. The OLP group presented statistically significant differences in reactive oxygen species (ROS) (29 600 cps) in comparison with the control group (39 679 cps) (P < 0.05). In the BMS group, ROS was 29 707 cps with significant difference in comparison with the control group (P < 0.05). Significantly higher salivary nitric oxide (145.7 μmol) and nitrite (141.0 μmol) levels were found in OLP patients in comparison with control group (P < 0.05). Increases in nitric oxide and C-reactive protein were found in the saliva of OLP patients in comparison with BMS and control patients. Further studies are required to confirm these findings. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Systematic study of metal-insulator-metal diodes with a native oxide

NASA Astrophysics Data System (ADS)

Donchev, E.; Gammon, P. M.; Pang, J. S.; Petrov, P. K.; Alford, N. McN.

2014-10-01

In this paper, a systematic analysis of native oxides within a Metal-Insulator-Metal (MIM) diode is carried out, with the goal of determining their practicality for incorporation into a nanoscale Rectenna (Rectifying Antenna). The requirement of having a sub-10nm oxide scale is met by using the native oxide, which forms on most metals exposed to an oxygen containing environment. This, therefore, provides a simplified MIM fabrication process as the complex, controlled oxide deposition step is omitted. We shall present the results of an investigation into the current-voltage characteristics of various MIM combinations that incorporate a native oxide, in order to establish whether the native oxide is of sufficient quality for good diode operation. The thin native oxide layers are formed by room temperature oxidation of the first metal layer, deposited by magnetron sputtering. This is done in-situ, within the deposition chamber before depositing the second metal electrode. Using these structures, we study the established trend where the bigger the difference in metal workfunctions, the better the rectification properties of MIM structures, and hence the selection of the second metal is key to controlling the device's rectifying properties. We show how leakage current paths through the non-optimised native oxide control the net current-voltage response of the MIM devices. Furthermore, we will present the so-called diode figures of merit (asymmetry, non-linearity and responsivity) for each of the best performing structures.

[Oxidative stress in station service workers].

PubMed

Basso, A; Elia, G; Petrozzi, M T; Zefferino, R

2004-01-01

The aim of this study is to identify an oxidative stress in service station workers. Previous studies verified an increased incidence of leukemia and myeloma, however other authors haven't verified it. There are reports of nasal, pharyngeal, laryngeal, and lung cancer in service station workers. Our study wants to evaluate the oxidative balance in the fuel workers. We studied 44 subjects with gasoline exposure and 29 control subjects. We determined the blood concentrations of Glutathione reduced and oxidized, Protein sulfhydrylic (PSH) Vitamine E, Vitamine C, Malondialdehyde, Protein oxidized (OX-PROT) and beta carotene. The t test was performed to analyze the differences between the means, the Chi square was used to evaluate the statistical significance of associations between variable categorical (redox index). The Anova test excluded the confusing effect of age, smoke and alcohol habit. The mean age of the workers was 36.6 years, instead the control group was 38. In the workers Glutathione reduced, Vit. E and Beta carotene were lower than in the control subjects, this difference was statistically significant (p < 0.01). The Malondialdehyde concentration was higher in the workers higher than in the control group, but this difference wasn't statistically significant. Our data demonstrated Glutathione, Vit. E, and Beta carotene are useful to verify a reduction of the antioxidant activity. The only marker of the presence of oxidative injury that correlated to work exposure was the malondialdehyde. The redox index was surest marker. The limit of our study is the number of control group, it was little and lower than workers. Conclusively we believe it's useful to continue our studies and, if our results are going to be confirmed, we retain that stress oxidative determination would be verified in occupational medicine using these markers, especially to study exposure of the fuel workers who were investigated less and, in our opinion, would receive more attention.

Clinical and electrodiagnostic characteristics of nitrous oxide-induced neuropathy in Taiwan.

PubMed

Li, Han-Tao; Chu, Chun-Che; Chang, Kuo-Hsuan; Liao, Ming-Feng; Chang, Hong-Shiu; Kuo, Hung-Chou; Lyu, Rong-Kuo

2016-10-01

Nitrous oxide-induced neuropathy is toxic neuropathy occasionally encountered in Taiwanese neurological clinics. Only several case reports described their electrodiagnostic features. We used a case-control design to investigate the detailed electrodiagnostic characteristics and possible factors relating to severe nerve injury. We retrospectively reviewed 33 patients with nitrous oxide-induced neuropathy over a 10-year period and reported their demographic data, spinal cord MRI, laboratory examinations and nerve conduction studies. 56 healthy controls' nerve conduction studies were collected for comparison analysis. We noted significant motor and sensory amplitudes reduction, conduction velocities slowing, and latencies prolongation in most tested nerves compared to the controls. Similar nerve conduction study characteristics with prominent lower limbs' motor and sensory amplitudes reduction was observed in patient groups with or without abnormal vitamin B12 and/or homocysteine levels. Among those with lower limbs' motor or sensory amplitudes reduction <20% of the lower limit of normal, higher homocysteine levels were detected. Severe impairments of the lower limbs' sensory and motor amplitudes were frequently noted in patients with nitrous oxide exposure. Nitrous oxide exposure itself is an important factor for the development of neuropathy. Our study contributes to the understanding of electrodiagnostic features underlying the nitrous oxide-induced neuropathy. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Inhalation analgesia with nitrous oxide versus other analgesic techniques in hysteroscopic polypectomy: a pilot study.

PubMed

Del Valle Rubido, Cristina; Solano Calvo, Juan Antonio; Rodríguez Miguel, Antonio; Delgado Espeja, Juan José; González Hinojosa, Jerónimo; Zapico Goñi, Álvaro

2015-01-01

To show the decrease in pain and better tolerance to inhalation analgesia with a 50% equimolar mixture of nitrogen protoxide and oxygen in hysteroscopic polypectomy compared with paracervical anesthesia and a control group. One hundred six patients scheduled for office hysteroscopy and polypectomy were divided into the following 3 groups: the control group, the nitrous oxide group, and the paracervical infiltration group. Patients were assigned sequentially (Canadian Task Force classification II-1). The study took place in a hysteroscopy outpatient clinic under the supervision of a gynecologist and 2 nurses trained to cooperate in the trial. One hundred six women from Area III of Madrid Community, Spain, who had been diagnosed with endometrial polyps at a gynecology office and were scheduled for office hysteroscopy and polypectomy agreed to participate in the study. Patients in group 1 (control group) received no treatment. Group 2 received inhaled nitrous oxide and group 3 paracervical infiltration with 1% lidocaine. Pain was assessed using the visual analog scale (0-10). Pain perceived by patients was lower in the nitrous Oxide group (mean: 3.55 ± 0.60, median: 3) versus the control group (mean: 5.49 ± 1.88, median: 6, p < .05) and the paracervical infiltration group (mean: 4.22 ± 1.73, median: 5). Tolerance to pain, assessed by the medical staff using qualitative variables, was bad for the control group, very good for the nitrous oxide group, and good for the paracervical infiltration group (p < .05). There were no complications in 82% of the patients in the nitrous oxide group, whereas in the paracervical infiltration group, there were complications in more than 50% of the patients. No severe complications occurred. Nitrous oxide is a safe and effective analgesic technique for polipectomy office hysteroscopy compared with the paracervical infiltration and control groups. Copyright © 2015 AAGL. Published by Elsevier Inc. All rights reserved.

Oxidation of GaSb(100) and its control studied by scanning tunneling microscopy and spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mäkelä, J., E-mail: jaakko.m.makela@utu.fi, E-mail: pekka.laukkanen@utu.fi, E-mail: rmwallace@utdallas.edu; Tuominen, M.; Yasir, M.

2015-08-10

Atomic-scale knowledge and control of oxidation of GaSb(100), which is a potential interface for energy-efficient transistors, are still incomplete, largely due to an amorphous structure of GaSb(100) oxides. We elucidate these issues with scanning-tunneling microscopy and spectroscopy. The unveiled oxidation-induced building blocks cause defect states above Fermi level around the conduction-band edge. By interconnecting the results to previous photoemission findings, we suggest that the oxidation starts with substituting second-layer Sb sites by oxygen. Adding small amount of indium on GaSb(100), resulting in a (4 × 2)-In reconstruction, before oxidation produces a previously unreported, crystalline oxidized layer of (1 × 3)-O free of gap states.

Thiol Disulfide Homeostasis in Schizophrenic Patients Using Atypical Antipsychotic Drugs

PubMed Central

Ersan, Etem Erdal; Aydin, Hüseyin; Erdoğan, Serpil; Erşan, Serpil; Alişik, Murat; Bakir, Sevtap; Erel, Özcan; Koç, Derya

2018-01-01

Objective Schizophrenia is a severe, debilitating mental disorder characterized by behavioral abnormalities. Although several studies have investigated the role of oxidative stress and the effects of antipsychotic drugs on oxidative markers in schizophrenia, adequate information is not available on these issues. The aim of this study is to determine the changes in oxidative status and thiol disulfide homeostasis in schizophrenic patients using atypical antipsychotic drugs. Methods Thirteen schizophrenic patients using atypical antipsychotic drugs and 30 healthy controls were included this study. The concentrations of total oxidant status (TOS), total antioxidant status (TAS), native thiol, total thiol, and disulfide levels were determined in the study population. Results The TAS (p=0.001), total thiol, and native thiol levels (p<0.001) were higher in the patients compared to the controls, whereas the TOS and disulfide levels were lower in the patients than in the controls (p<0.001). Conclusion These results may suggest that atypical antipsychotic drugs have a useful therapeutic effect by reducing oxidative stress via the inhibition of the formation of disulfide bonds. The study population number was one of the limitations of this study. Therefore, further studies are needed to establish the association between thiol disulfide homeostasis in schizophrenic patients using atypical antipsychotic drugs. PMID:29397665

Nitric oxide fumigation for control of bulb mites on flower bulbs and tubers

USDA-ARS?s Scientific Manuscript database

Nitric oxide fumigation was studied for efficacy to control bulb mites in the genus Rhizoglyphus and effects on germination and growth of flower bulbs and tubers. Bulb mites on infested peanuts were fumigated with nitric oxide at different concentrations under ultralow oxygen conditions in 1.9L jar...

Markers of oxidative DNA damage in human interventions with fruit and berries.

PubMed

Freese, Riitta

2006-01-01

Diets rich in fruit and vegetables are associated with a decreased risk of several cancers via numerous possible mechanisms. For example, phytochemicals may decrease oxidative DNA damage and enhance DNA repair. Markers of oxidative DNA damage in human dietary intervention trials used most frequently include oxidized nucleosides such as 7-hydro-8-oxo-2'-deoxyguanosine, which can be analyzed from isolated DNA or urine. Single-cell gel electrophoresis has been widely used to measure baseline or H2O2-induced DNA strand breaks or sites of modified bases sensitive to repair enzymes recognizing oxidized purines or pyrimidines. Recently, markers of DNA repair also have been used. Few controlled human dietary interventions have investigated the specific effects of fruit or berries. There are indications that kiwifruit can decrease H2O2 sensitivity of lymphocyte DNA ex vivo and enhance DNA repair. Carefully controlled studies with flavonoid-rich fruit or berry juices found only few significant differences; less rigorously controlled studies gave more optimistic results. Data on the effects of fruit and berries on DNA damage in humans are scarce and inconclusive; adequately controlled studies with validated markers are needed. Because levels of DNA damage are usually low in young healthy volunteers, groups with an enhanced risk of DNA damage should be studied.

Reduced SIRT1 expression correlates with enhanced oxidative stress in compensated and decompensated heart failure

PubMed Central

Akkafa, Feridun; Halil Altiparmak, Ibrahim; Erkus, Musluhittin Emre; Aksoy, Nurten; Kaya, Caner; Ozer, Ahmet; Sezen, Hatice; Oztuzcu, Serdar; Koyuncu, Ismail; Umurhan, Berrin

2015-01-01

Sirtuin-1 (SIRT1) is a longevity factor in mammals initiating the cell survival mechanisms, and preventing ischemic injury in heart. In the etiopathogenesis of heart failure (HF), impairment in cardiomyocyte survival is a notable factor. Oxidative stress comprises a critical impact on cardiomyocyte lifespan in HF. The aim of the present study was to investigate SIRT1 expression in patients with compensated (cHF) and decompensated HF (dHF), and its correlation with oxidative stress. SIRT1 expression in peripheral leukocytes was examined using quantitative RT-PCR in 163 HF patients and 84 controls. Serum total oxidant status (TOS) and total antioxidant status (TAS) were measured via colorimetric assays, and oxidative stress index (OSI) was calculated. Lipid parameters were also determined by routine laboratory methods. SIRT1 mRNA expression was significantly downregulated in HF with more robust decrease in dHF (p=0.002, control vs cHF; p<0.001, control vs dHF). Markedly increased oxidative stress defined as elevated TOS, OSI and low TAS levels were detected in HF patients comparing with the controls (TAS; p=0.010, control vs cHF, p=0.045 control vs dHF, TOS; p=0.004 control vs cHF; p<0.001 control vs dHF, OSI; p<0.001 for both comparisons, respectively). With SIRT1 expression levels, TAS, TOS, OSI, and high density lipoprotein levels in cHF and dHF were determined correlated. SIRT1 expression were significantly reduced in both HF subtypes, particularly in dHF. SIRT1 expression was correlated with the oxidant levels and antioxidant capacity. Data suggest that SIRT1 may have a significant contribution in regulation of oxidant/antioxidant balance in HF etiology and compensation status. PMID:26233702

Auto antibodies against oxidized low density lipoprotein in severe preeclampsia.

PubMed

Jain, Meenakshi; Sawhney, Harjeet; Aggarwal, Neelam; Vashistha, Kala; Majumdhar, Siddarth

2004-06-01

To study autoantibody titres against oxidized low density lipoprotein in preeclamsia. Ten millimeters of heparinized blood samples were collected from 20 primigravidae with severe preeclamsia (study group) and 20 gestation-matched normotensive primigravidae (control group). Concentration of malondialdehyde, metabolite of lipid peroxidation were measured in sera by HPLC and autoantibodies against oxidized low density lipoproteins (obtained after oxidation with 2 mm CuSO(4)) were determined by ELISA. Statistical analysis was performed by Student's t-test and chi(2) test. Mean triglyceride levels were significantly (P < 0.001) higher in the study group (193.20 +/- 31.16 mg/dL) compared to the control group (170.60 +/- 23.2 mg/dL). Mean plasma lipid per oxide levels were not significantly different between the study (4.45 +/- 1.28 mmol/mL) and control (3.88 +/- 0.99 mmol/mL) groups. The majority of women in both groups had low antibody titres (<1.32) against low density lipoprotein. Six women (30%) of the study group and four (20%) of the control group had high autoantibody titres (>/=1.32). In preeclamptic women, diastolic blood pressure, the amount of urinary protein excretion and the plasma level of urea were significantly higher (P < 0.05) in patients with higher auto antibody titre. Titres of autoantibodies to oxidized low density lipoprotein were similar in normotensive and preeclamptic women. In preeclamptic women, titres correlated positively with the severity of preeclampsia.

A longitudinal study of atrazine and 2,4-D exposure and oxidative stress markers among Iowa corn farmers

PubMed Central

Lerro, Catherine C.; Beane Freeman, Laura E.; Portengen, Lützen; Kang, Daehee; Lee, Kyoungho; Blair, Aaron; Lynch, Charles F.; Bakke, Berit; De Roos, Anneclaire J.; Vermeulen, Roel C.H.

2018-01-01

Reactive oxygen species, potentially formed through environmental exposures, can overwhelm an organism’s antioxidant capabilities resulting in oxidative stress. Long-term oxidative stress is linked with chronic diseases. Pesticide exposures have been shown to cause oxidative stress in vivo. We utilized a longitudinal study of corn farmers and non-farming controls in Iowa to examine the impact of exposure to the widely used herbicides atrazine and 2,4-dichlorophenoxyacetic acid (2,4-D) on markers of oxidative stress. 225 urine samples were collected during five agricultural time periods (pre-planting, planting, growing, harvest, off-season) for 30 farmers who applied pesticides occupationally and 10 controls who did not; all were non-smoking men ages 40–60. Atrazine mercapturate (atrazine metabolite), 2,4-D, and oxidative stress markers (malondialdehyde [MDA], 8-hydroxy-2′-deoxyguanosine [8-OHdG], and 8-isoprostaglandin-F2α [8-isoPGF]) were measured in urine. We calculated β estimates and 95% confidence intervals (95%CI) for each pesticide-oxidative stress marker combination using multivariate linear mixed-effect models for repeated measures. Farmers had higher urinary atrazine mercapturate and 2,4-D levels compared to controls. In regression models, after natural log transformation, 2,4-D was associated with elevated levels of 8-OHdG (β=0.066, 95%CI=0.008–0.124) and 8-isoPGF (β=0.088, 95%CI=0.004–0.172). 2,4-D may be associated with oxidative stress because of modest increases in 8-OHdG, a marker of oxidative DNA damage, and 8-isoPGF, a product of lipoprotein peroxidation, with recent 2,4-D exposure. Future studies should investigate the role of 2,4-D-induced oxidative stress in the pathogenesis of human diseases. PMID:28116766

A meta-analysis of biomarkers related to oxidative stress and nitric oxide pathway in migraine.

PubMed

Neri, Monica; Frustaci, Alessandra; Milic, Mirta; Valdiglesias, Vanessa; Fini, Massimo; Bonassi, Stefano; Barbanti, Piero

2015-09-01

Oxidative and nitrosative stress are considered key events in the still unclear pathophysiology of migraine. Studies comparing the level of biomarkers related to nitric oxide (NO) pathway/oxidative stress in the blood/urine of migraineurs vs. unaffected controls were extracted from the PubMed database. Summary estimates of mean ratios (MR) were carried out whenever a minimum of three papers were available. Nineteen studies were included in the meta-analyses, accounting for more than 1000 patients and controls, and compared with existing literature. Most studies measuring superoxide dismutase (SOD) showed lower activity in cases, although the meta-analysis in erythrocytes gave null results. On the contrary, plasma levels of thiobarbituric acid reactive substances (TBARS), an aspecific biomarker of oxidative damage, showed a meta-MR of 2.20 (95% CI: 1.65-2.93). As for NOs, no significant results were found in plasma, serum and urine. However, higher levels were shown during attacks, in patients with aura, and an effect of diet was found. The analysis of glutathione precursor homocysteine and asymmetric dimethylarginine (ADMA), an NO synthase inhibitor, gave inconclusive results. The role of the oxidative pathway in migraine is still uncertain. Interesting evidence emerged for TBARS and SOD, and concerning the possible role of diet in the control of NOx levels. © International Headache Society 2015.

Biomarkers of oxidative stress and DNA damage in agricultural workers: A pilot study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muniz, Juan F.; McCauley, Linda; Scherer, J.

Oxidative stress and DNA damage have been proposed as mechanisms linking pesticide exposure to health effects such as cancer and neurological diseases. A study of pesticide applicators and farmworkers was conducted to examine the relationship between organophosphate pesticide exposure and biomarkers of oxidative stress and DNA damage. Urine samples were analyzed for OP metabolites and 8-hydroxy-2'-deoxyguanosine (8-OH-dG). Lymphocytes were analyzed for oxidative DNA repair activity and DNA damage (Comet assay), and serum was analyzed for lipid peroxides (i.e., malondialdehyde, MDA). Cellular damage in agricultural workers was validated using lymphocyte cell cultures. Urinary OP metabolites were significantly higher in farmworkers andmore » applicators (p < 0.001) when compared to controls. 8-OH-dG levels were 8.5 times and 2.3 times higher in farmworkers or applicators (respectively) than in controls. Serum MDA levels were 4.9 times and 24 times higher in farmworkers or applicators (respectively) than in controls. DNA damage (Comet assay) and oxidative DNA repair were significantly greater in lymphocytes from applicators and farmworkers when compared with controls. Markers of oxidative stress (i.e., increased reactive oxygen species and reduced glutathione levels) and DNA damage were also observed in lymphocyte cell cultures treated with an OP. The findings from these in vivo and in vitro studies indicate that organophosphate pesticides induce oxidative stress and DNA damage in agricultural workers. These biomarkers may be useful for increasing our understanding of the link between pesticides and a number of health effects.« less

Oxygen Isotope Signatures of Biogenic Manganese(III/IV) Oxides

NASA Astrophysics Data System (ADS)

Sutherland, K. M.; Hansel, C. M.; Wankel, S. D.

2015-12-01

Manganese (Mn) oxide minerals are pervasive throughout a number of surface earth environments as rock varnishes, ferromanganese nodules, crusts around deep-sea vents, and cave deposits among many other marine, freshwater, and terrestrial deposits. Mn(III,IV) oxides are also among the strongest sorbents and oxidants in surface earth environments and are crucial to understanding the fate of organic matter in sedimentary environments. The precipitation of Mn oxide minerals proceeds via both abiotic and biotic oxidation pathways, the latter due to the indirect or direct activity of Mn(II)- oxidizing microorganisms, including bacteria and fungi. Although the precipitation of Mn oxides is believed to be primarily controlled by Mn(II)-oxidizing organisms in most surface earth environments, confirmation of this generally held notion has remained illusive and limits our understanding of their formation on Earth and beyond (e.g., Mars). Previous work provided evidence that O atom incorporation by specific Mn oxidation pathways may exhibit unique and predictable isotopic fractionation. In this study, we expand upon this evidence by measuring the oxygen isotope signature of several biogenic and abiogenic Mn oxide minerals synthesized under a range of oxygen-18 labeled water. These results allow us to determine the relative amount oxygen atoms derived from water and molecular oxygen that are incorporated in the oxide and shed light on corresponding isotope fractionation factors. Additionally, we show that, once precipitated, Mn oxide isotope signatures are robust with respect to aqueous oxygen isotope exchange. The study provides a foundation on which to study and interpret Mn oxides in natural environments and determine which environmental controls may govern Mn(II) oxidation.

Influence of Oxidative Stress on Biocontrol Activity of Cryptococcus laurentii against Blue Mold on Peach Fruit.

PubMed

Zhang, Zhanquan; Chen, Jian; Li, Boqiang; He, Chang; Chen, Yong; Tian, Shiping

2017-01-01

The limitations of chemical fungicides for the control of postharvest diseases have recently become more apparent. The utilization of antagonistic microorganisms is a promising alternative to that of fungicides to control postharvest decay. In previous studies, the antagonistic yeast Cryptococcus laurentii has shown excellent effects of biocontrol and great potential for practical application. Adverse conditions, such as oxidative stress, limit the practical application of antagonistic yeast. In this study, we investigated the oxidative stress tolerance of C. laurentii and the associated mechanisms. The results indicated that exogenous oxidative stress has a significant effect on the viability and biocontrol efficiency of C. laurentii . H 2 O 2 -induced oxidative stress led to the accumulation of reactive oxygen species. The results of flow cytometric analysis suggested that apoptosis is responsible for the reduced survival rate of C. laurentii under oxidative stress. Using tests of antioxidant activity, we found that C. laurentii could employ enzymatic systems to resist exogenous oxidative stress. The addition of exogenous glutathione, a non-enzymatic antioxidant, to the media can significantly enhance oxidative tolerance and biocontrol efficiency of C. laurentii .

Influence of Oxidative Stress on Biocontrol Activity of Cryptococcus laurentii against Blue Mold on Peach Fruit

PubMed Central

Zhang, Zhanquan; Chen, Jian; Li, Boqiang; He, Chang; Chen, Yong; Tian, Shiping

2017-01-01

The limitations of chemical fungicides for the control of postharvest diseases have recently become more apparent. The utilization of antagonistic microorganisms is a promising alternative to that of fungicides to control postharvest decay. In previous studies, the antagonistic yeast Cryptococcus laurentii has shown excellent effects of biocontrol and great potential for practical application. Adverse conditions, such as oxidative stress, limit the practical application of antagonistic yeast. In this study, we investigated the oxidative stress tolerance of C. laurentii and the associated mechanisms. The results indicated that exogenous oxidative stress has a significant effect on the viability and biocontrol efficiency of C. laurentii. H2O2-induced oxidative stress led to the accumulation of reactive oxygen species. The results of flow cytometric analysis suggested that apoptosis is responsible for the reduced survival rate of C. laurentii under oxidative stress. Using tests of antioxidant activity, we found that C. laurentii could employ enzymatic systems to resist exogenous oxidative stress. The addition of exogenous glutathione, a non-enzymatic antioxidant, to the media can significantly enhance oxidative tolerance and biocontrol efficiency of C. laurentii. PMID:28210254

Effects of a fruit-vegetable dietary pattern on oxidative stress and genetic damage in coke oven workers: a cross-sectional study.

PubMed

Xie, Zheng; Lin, Haijiang; Fang, Renfei; Shen, Weiwei; Li, Shuguang; Chen, Bo

2015-05-06

Coke oven workers (COWs) are exposed to high level of genotoxic chemicals that induce oxidative stress and genetic damage. The dietary intake of certain types of foods may reverse these effects. We conducted a cross-sectional study with 51 topside COWs, 79 other COWs, and 67 controls, to assess the effects of dietary patterns on oxidative stress and genetic damage. Compared to the controls, both topside and other COWs had significantly higher urinary 1-hydroxypyrene levels, serum oxidant levels [malondialdehyde, (MDA)], and genetic damage [micronucleus (MN) frequency & 8-oxo-2'-deoxyguanosine (8-OH-dG)], but lower antioxidant levels [superoxide dismutase (SOD) and glutathione peroxidase, (GPx)]. The fruit-vegetable (FV) dietary pattern was positively correlated with serum SOD levels and negative correlated with serum MDA, MN frequency, and urinary 8-OH-dG. COWs with an FV patter in the highest quartile (Q4) had significantly increased antioxidant levels (SOD and GPx) and decreased oxidant levels (MDA) and genetic damage (MN frequency and 8-OH-dG) than those with an FV pattern in the lowest quartile (Q1). Compared to control subjects, COWs had increased oxidative stress and genetic damage. A FV dietary pattern may reverse oxidative stress and genetic damage in COWs.

Grape seed proanthocyanidins prevent plasma postprandial oxidative stress in humans.

PubMed

Natella, Fausta; Belelli, Federica; Gentili, Vincenzo; Ursini, Fulvio; Scaccini, Cristina

2002-12-18

Postprandial hyperlipemia is a well-defined risk factor for atherosclerosis. A reasonable contributing mechanism could involve the postprandial increase of plasma lipid hydroperoxides (LPO) affecting the oxidant/antioxidant balance and increasing the susceptibility of LDL to oxidation. Wine has been shown to prevent both these events. The present study was designed to investigate the effect of supplementing a meal with grape seed proanthocyanidins (the main phenolic antioxidant of red wine) on plasma postprandial oxidative stress. In two different sessions, 8 healthy volunteers consumed the same test meal rich in oxidized and oxidizable lipids without (control) or with 300 mg of a proanthocyanidin-rich grape seeds extract (GSE). Lipid hydroperoxide concentration, antioxidant status, and LDL resistance to oxidative modification were measured in postprandial plasma. The content of LPO in chylomicrons was 1.5-fold higher after the control meal than after the GSE-supplemented meal. Plasma LPO increased only after consumption of the control meal. The plasma antioxidant capacity increased in the postprandial phase only following the GSE supplemented meal. LDL isolated 3 h after the control meal tended to be more susceptible to oxidative modification (but the difference did not reach statistical significance). An opposite trend was observed following the GSE supplemented meal. In conclusion, the supplementation of a meal with GSE minimizes the postprandial oxidative stress by decreasing the oxidants and increasing the antioxidant levels in plasma, and, as a consequence, enhancing the resistance to oxidative modification of LDL.

A natural pharma standard supplement formulation to control treatment-related toxicity and oxidative stress in genitourinary cancer: a preliminary study.

PubMed

Ledda, A; Belcaro, G; Dugall, M; Luzzi, R; Hosoi, M; Feragalli, B; Cotellese, R; Cosentino, V; Cosentino, M; Eggenhoffner, R; Pellizzato, M; Fratter, A; Giacomelli, L

2017-09-01

Oncological treatments are associated with toxicities that may decrease compliance to treatment in most genitourinary cancer patients. Supplementation with pharmaceutical-standardized supplement may be a supplementary method to control the side effects after chemo- and radiotherapy and the increased oxidative stress associated to treatments. This registry study evaluated a natural combination of supplements containing curcumin, cordyceps, and astaxanthin (Oncotris™) used as supplementary management in genitourinary cancer patients who had undergone oncological therapy. Patients with genitourinary cancers (prostate or bladder malignancies) who had undergone and completed cancer treatments (radiotherapy, chemotherapy or intravesical immunotherapy with increased oxidative stress and residual symptoms) were recruited in this registry, supplement study. Registry subjects (n = 61) freely decided to follow either a standard management (SM) (control group = 35) or SM plus oral daily supplementation (supplement group = 26). Evaluation of severity of treatment-related residual side effects, blood count test, prostate-specific antigen (PSA) test and plasma free radicals (oxidative stress) were performed at inclusion and at the end of the observational period (6 weeks). Two patients dropped out during the registry. Therefore, the analysis included 59 participants: 26 individuals in the supplementation group and 33 in the control group. In the supplement group, the intensity of signs and symptoms (treatment-related) and residual side effects significantly decreased at 6 weeks: minimal changes were observed in controls. Supplementation with Oncotris™ was associated with a significant improvement in blood cell count and with a decreased level of plasmatic PSA and oxidative stress. Naturally-derived supplements, specifically Oncotris™ (patent pending), could support the body to overcome the treatment-related toxicities - and the relative oxidative stress in cancer patients.

Hybrid Nanomaterials with Single-Site Catalysts by Spatially Controllable Immobilization of Nickel Complexes via Photoclick Chemistry for Alkene Epoxidation.

PubMed

Ghosh, Dwaipayan; Febriansyah, Benny; Gupta, Disha; Ng, Leonard Kia-Sheun; Xi, Shibo; Du, Yonghua; Baikie, Tom; Dong, ZhiLi; Soo, Han Sen

2018-05-22

Catalyst deactivation is a persistent problem not only for the scientific community but also in industry. Isolated single-site heterogeneous catalysts have shown great promise to overcome these problems. Here, a versatile anchoring strategy for molecular complex immobilization on a broad range of semiconducting or insulating metal oxide ( e. g., titanium dioxide, mesoporous silica, cerium oxide, and tungsten oxide) nanoparticles to synthesize isolated single-site catalysts has been studied systematically. An oxidatively stable anchoring group, maleimide, is shown to form covalent linkages with surface hydroxyl functionalities of metal oxide nanoparticles by photoclick chemistry. The nanocomposites have been thoroughly characterized by techniques including UV-visible diffuse reflectance spectroscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, and X-ray absorption spectroscopy (XAS). The IR spectroscopic studies confirm the covalent linkages between the maleimide group and surface hydroxyl functionalities of the oxide nanoparticles. The hybrid nanomaterials function as highly efficient catalysts for essentially quantitative oxidations of terminal and internal alkenes and show molecular catalyst product selectivities even in more eco-friendly solvents. XAS studies verify the robustness of the catalysts after several catalytic cycles. We have applied the photoclick anchoring methodology to precisely control the deposition of a luminescent variant of our catalyst on the metal oxide nanoparticles. Overall, we demonstrate a general approach to use irradiation to anchor molecular complexes on oxide nanoparticles to create recyclable, hybrid, single-site catalysts that function with high selectivity in a broad range of solvents. We have achieved a facile, spatially and temporally controllable photoclick method that can potentially be extended to other ligands, catalysts, functional molecules, and surfaces.

Study on emission characteristics and reduction strategy of nitrous oxide during wastewater treatment by different processes.

PubMed

Sun, Shichang; Bao, Zhiyuan; Sun, Dezhi

2015-03-01

Given the inexorable increase in global wastewater treatment, increasing amounts of nitrous oxide are expected to be emitted from wastewater treatment plants and released to the atmosphere. It has become imperative to study the emission and control of nitrous oxide in the various wastewater treatment processes currently in use. In the present investigation, the emission characteristics and the factors affecting the release of nitrous oxide were studied via full- and pilot-scale experiments in anoxic-oxic, sequencing batch reactor and oxidation ditch processes. We propose an optimal treatment process and relative strategy for nitrous oxide reduction. Our results show that both the bio-nitrifying and bio-denitrifying treatment units in wastewater treatment plants are the predominant sites for nitrous oxide production in each process, while the aerated treatment units are the critical sources for nitrous oxide emission. Compared with the emission of nitrous oxide from the anoxic-oxic (1.37% of N-influent) and sequencing batch reactor (2.69% of N-influent) processes, much less nitrous oxide (0.25% of N-influent) is emitted from the oxidation ditch process, which we determined as the optimal wastewater treatment process for nitrous oxide reduction, given the current technologies. Nitrous oxide emissions differed with various operating parameters. Controlling the dissolved oxygen concentration at a proper level during nitrification and denitrification and enhancing the utilization rate of organic carbon in the influent for denitrification are the two critical methods for nitrous oxide reduction in the various processes considered.

Oxidative stress and frailty: A systematic review and synthesis of the best evidence.

PubMed

Soysal, Pinar; Isik, Ahmet Turan; Carvalho, Andre F; Fernandes, Brisa S; Solmi, Marco; Schofield, Patricia; Veronese, Nicola; Stubbs, Brendon

2017-05-01

Oxidative stress (OS) is associated with accelerated aging. Previous studies have suggested a possible relationship between OS and frailty but this association remains unclear. We conducted a systematic review to investigate potential interactions between OS and frailty. A systematic literature search of original reports providing data on 'OS and antioxidant' parameters and frailty was carried out across major electronic databases from inception until May 2016. Cross-sectional/case control and longitudinal studies reporting data on the association between frailty and anti-oxidants-OS biomarkers were considered for inclusion. Results were summarized with a synthesis based on the best evidence. From 1856 hits, 8 studies (cross-sectional/case control) were included (N=6349; mean age of 75±12years; 56.4% females). Overall, there were 588 (=9.3%) frail, 3036 pre-frail (=47.8%), 40 (=0.6%) pre-frail/robust, and 2685 (=42.3%) robust subjects. Six cross-sectional/case control studies demonstrated that frailty was associated with an increase in peripheral OS biomarkers, including lipoprotein phospholipase A2 (1 study), isoprostanes (2 studies), malonaldehyde (2 studies), 8-hydroxy-20-deoxyguanosine (2 studies), derivate of reactive oxygen metabolites (2 studies), oxidized glutathione/glutathione (1 study), 4-hydroxy-2,3-nonenal (1 study), and protein carbonylation levels (1 study). In addition, preliminary evidence points to lower anti-oxidant parameters (vitamin C, E, α-tocopherol, biological anti-oxidant potential, total thiol levels) in frailty. Frailty and pre-frailty appear to be associated with higher OS and possibly lower anti-oxidant parameters. However, due to the cross-sectional design, it is not possible to disentangle the directionality of the relationships observed. Thus, future high-quality and in particular longitudinal research is required to confirm or refute these relationships and to further elucidate pathophysiological mechanisms. Copyright © 2017 Elsevier B.V. All rights reserved.

Rapid in situ generation of two patterned chemoselective surface chemistries from a single hydroxy-terminated surface using controlled microfluidic oxidation.

PubMed

Pulsipher, Abigail; Westcott, Nathan P; Luo, Wei; Yousaf, Muhammad N

2009-06-10

In this work, we develop a new, rapid and inexpensive method to generate spatially controlled aldehyde and carboxylic acid surface groups by microfluidic oxidation of 11-hydroxyundecylphosphonic acid self-assembled monolayers (SAMs) on indium tin oxide (ITO) surfaces. SAMs are activated and patterned using a reversibly sealable, elastomeric polydimethylsiloxane cassette, fabricated with preformed micropatterns by soft lithography. By flowing the mild oxidant pyridinium chlorochromate through the microchannels, only selected areas of the SAM are chemically altered. This microfluidic oxidation strategy allows for ligand immobilization by two chemistries originating from a single SAM composition. ITO is robust, conductive, and transparent, making it an ideal platform for studying interfacial interactions. We display spatial control over the immobilization of a variety of ligands on ITO and characterize the resulting oxime and amide linkages by electrochemistry, X-ray photoelectron spectroscopy, contact angle, fluorescence microscopy, and atomic force microscopy. This general method may be used with many other materials to rapidly generate patterned and tailored surfaces for studies ranging from molecular electronics to biospecific cell-based assays and biomolecular microarrays.

Oxidative stress markers and genetic polymorphisms of glutathione S-transferase T1, M1, and P1 in a subset of children with autism spectrum disorder in Lagos, Nigeria.

PubMed

Oshodi, Y; Ojewunmi, O; Oshodi, T A; Ijarogbe, G T; Ogun, O C; Aina, O F; Lesi, Fea

2017-09-01

The role of oxidative stress has been identified in the development of autism spectrum disorder (ASD), and polymorphisms of glutathione S-transferase have been associated with some diseases linked to oxidative stress. Hence, we evaluated the serum levels of oxidative stress markers and investigated genetic polymorphisms of glutathione S-transferase associated with autism. Forty-two children clinically diagnosed with ASD using the Diagnostic and Statistical Manual for Mental Disorders (DSM-5) criteria and a clinical interview were included in the study. Twenty-three age-matched controls without any known genetic/developmental disorder were also recruited. Oxidative stress markers along with the genetic polymorphisms of glutathione S-transferase were determined. Reduced glutathione in ASD patients was significantly lower than the control (P = 0.008), whereas other oxidative stress markers measured were not significantly different in both the control and case populations. The frequencies of GSTT1 and GSTM1 null genotypes were lower among the controls compared with the cases, however, no association risk was observed. The observed risk of carrying Val/Val genotype among the cases was approximately six times that of the controls. Individuals with ASD showed a significant diminished level of reduced glutathione, however, the distribution of GSTT1, GSTM1, and GSTP1 polymorphisms was not found to be associated with autism in this study population.

40 CFR 63.361 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... oxidation control device or at the exhaust point from the combustion chamber of a thermal oxidation control... scrubber achieves at least 99-percent control of ethylene oxide emissions. Oxidation temperature means the temperature at the outlet point of a catalytic oxidation unit control device or at the exhaust point from the...

Variability of serum oxidative stress biomarkers relative to biochemical data and clinical parameters of glaucoma patients

PubMed Central

Yemişci, Bülent; Yiğit, Ulviye; Ağaçhan, Ahmet; Coşkun, Cihan

2010-01-01

Purpose The importance of oxidative stress in both the formation and the course of glaucoma has been known. Among the antioxidants, vitamin E possesses the specific effects and regulatory mechanisms of a neurohormone. The serum oxidant/antioxidant profile is reportedly altered in ocular pathologies. In this study, we analyzed the effect of the clinical parameters of glaucoma and biochemical data on antioxidants and serum oxidative stress markers as oxidation degradation products. Methods In this multicenter case control study, control and patient groups consisted of 31 healthy individuals and 160 glaucoma patients with no known additional abnormalities, respectively. We analyzed the oxidation degradation products malonyl dialdehyde (MDA), advanced oxidation protein products (AOPP), antioxidants, vitamins E and A, Serine (Ser), superoxide dismutase (SOD), glutathione peroxidase (Gpx), transferrine (TF), and total antioxidant capacity (TADA). All of these parameters and their relationships with serum cholesterol, glucose, protein, albumin, triglyceride levels, age, gender, visual acuities, intraocular pressure (IOP), c/d ratio, gonioscopic findings, medications, presence of pseudoexfoliation (px), central visual field and Optical Coherence Tomography (OCT) data, pachymetry, and Laplace values, were evaluated individually. Statistical comparisons were performed among them, and with the control group as well. Results TADA, AOPP, SOD, and Gpx were found to be decreased, and MDA, Ser, TF, vitamins A and E increased in the patient group. All data, excluding AOPP, varied significantly. Vitamin E was the most consistent parameter. Conclusions In this study, the association between glaucoma and lipid oxidation was shown on a systematic basis, and the significance of vitamin E as a neuroprotective agent has been revealed once more. PMID:20664701

Effects of grape seed polyphenols on oxidative damage in liver tissue of acutely and chronically exercised rats.

PubMed

Belviranlı, Muaz; Gökbel, Hakkı; Okudan, Nilsel; Büyükbaş, Sadık

2013-05-01

The objective of the present study was to investigate the effects of grape seed extract (GSE) supplementation on oxidative stress and antioxidant defense markers in liver tissue of acutely and chronically exercised rats. Rats were randomly assigned to six groups: Control (C), Control Chronic Exercise (CE), Control Acute Exercise (AE), GSE-supplemented Control (GC), GSE-supplemented Chronic Exercise(GCE) and GSE-supplemented Acute Exercise (GAE). Rats in the chronic exercise groups were subjected to a six-week treadmill running and in the acute exercise groups performed an exhaustive running. Rats in the GSE supplemented groups received GSE (100 mg.kg(-1) .day(-1) ) in drinking water for 6 weeks. Liver tissues of the rats were taken for the analysis of malondialdehyde (MDA), nitric oxide (NO) levels and total antioxidant activity (AOA) and xanthine oxidase (XO) activities. MDA levels decreased with GSE supplementation in control groups but increased in acute and chronic exercise groups compared to their non-supplemented control. NO levels increased with GSE supplementation. XO activities were higher in AE group compared to the CE group. AOA decreased with GSE supplementation. In conclusion, while acute exercise triggers oxidative stress, chronic exercise has protective role against oxidative stress. GSE has a limited antioxidant effect on exercise-induced oxidative stress in liver tissue.

Fasting rapidly increases fatty acid oxidation in white adipose tissue of young broiler chickens.

PubMed

Torchon, Emmanuelle; Ray, Rodney; Hulver, Matthew W; McMillan, Ryan P; Voy, Brynn H

2017-01-02

Upregulating the fatty acid oxidation capacity of white adipose tissue in mice protects against diet-induced obesity, inflammation and insulin resistance. Part of this capacity results from induction of brown-like adipocytes within classical white depots, making it difficult to determine the oxidative contribution of the more abundant white adipocytes. Avian genomes lack a gene for uncoupling protein 1 and are devoid of brown adipose cells, making them a useful model in which to study white adipocyte metabolism in vivo. We recently reported that a brief (5 hour) period of fasting significantly upregulated many genes involved in mitochondrial and peroxisomal fatty acid oxidation pathways in white adipose tissue of young broiler chickens. The objective of this study was to determine if the effects on gene expression manifested in increased rates of fatty acid oxidation. Abdominal adipose tissue was collected from 21 day-old broiler chicks that were fasted for 3, 5 or 7 hours or fed ad libitum (controls). Fatty acid oxidation was determined by measuring and summing 14 CO 2 production and 14 C-labeled acid-soluble metabolites from the oxidation of [1- 14 C] palmitic acid. Fasting induced a progressive increase in complete fatty acid oxidation and citrate synthase activity relative to controls. These results confirm that fatty acid oxidation in white adipose tissue is dynamically controlled by nutritional status. Identifying the underlying mechanism may provide new therapeutic targets through which to increase fatty acid oxidation in situ and protect against the detrimental effects of excess free fatty acids on adipocyte insulin sensitivity.

Improved Electrochromic Characteristics of a Honeycomb-Structured Film Composed of NiO.

PubMed

Yang, Hyeeun; Lee, Yulhee; Kim, Dong In; Seo, Hyeon Jin; Yu, Jung-Hoon; Nam, Sang-Hun; Boo, Jin-Hyo

2018-09-01

Color changes controlled by electronic energies have been studied for many years in order to fabricate energy-efficient smart windows. Reduction and oxidization of nickel oxide under the appropriate voltage can change the color of a window. For a superior nickel oxide (NiO) electrochromic device (ECD), it is important to control the chemical and physical characteristics of the surface. In this study, we applied polystyrene bead templates to nickel oxide films to fabricate a honeycomb-structured electrochromic (EC) layer. We synthesized uniform polystyrene beads using the chemical wet method and placed them on substrates to create honeycomb-structured NiO films. Then, the EC characteristics of the nickel oxide films with a honeycomb structure were evaluated with UV-Visible and cyclic voltammetry. FE-SEM and AFM were used to measure the morphologies of the nanostructures and the efficiencies of the redox reactions related to the specific surface area.

Controlling Synergistic Oxidation Processes for Efficient and Stable Blue Thermally Activated Delayed Fluorescence Devices.

PubMed

Cui, Lin-Song; Deng, Ya-Li; Tsang, Daniel Ping-Kuen; Jiang, Zuo-Quan; Zhang, Qisheng; Liao, Liang-Sheng; Adachi, Chihaya

2016-09-01

Efficient sky-blue organic light-emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) display a three orders of magnitude increase in lifetime, which is superior to those of controlled phosphorescent OLEDs used in this study. The combination of electro-oxidation and photo-oxidation of the TADF emitters in their triplet excited-states is suppressed through molecule design and device engineering. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controllable Synthesis of Formaldehyde Modified Manganese Oxide Based on Gas-Liquid Interfacial Reaction and Its Application of Electrochemical Sensing.

PubMed

Bai, Wushuang; Sheng, Qinglin; Nie, Fei; Zheng, Jianbin

2015-12-30

Controllable synthesis of manganese oxides was performed via a simple one-step synthetic method. Then obtained manganese oxides which exhibit flower-like, cloud-like, hexagon-like, and rod-like morphologies were modified by formaldehyde based on a simple self-made gas-liquid reaction device respectively and the modified manganese oxides with coral-like, scallop-like and rod-like morphology were synthesized accordingly. The obtained materials were characterized and the formation mechanism was also researched. Then the modified manganese oxides were used to fabricate electrochemical sensors to detect H2O2. Comparison of electrochemical properties between three kinds of modified manganese oxides was investigated and the best one has been successfully employed as H2O2 sensor which shows a low detection limit of 0.01 μM, high sensitivity of 162.69 μA mM(-1) cm(-2), and wide linear range of 0.05 μM-12.78 mM. The study provides a new method for controllable synthesis of metal oxides, and electrochemical application of formaldehyde modified manganese oxides will provides a new strategy for electrochemical sensing with high performance, low cost, and simple fabrication.

Response to glucose and lipid infusions in sepsis: a kinetic analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shaw, J.H.; Wolfe, R.R.

The kinetics and oxidation of glucose and free fatty acid (FFA) metabolism were assessed in control and Escherichia coli septicemic dogs by using primed, constant infusions of U-/sup 14/C-glucose and 1,2, /sup 13/C-palmitic acid. In the controls, the infusion of glucose suppressed endogenous glucose production completely, whereas, in the septic dogs, only a 30% suppression of glucose production occurred. The ability of the septic dogs to oxidize endogenous or exogenous glucose was decreased significantly. The basal rate of appearance of FFA was significantly higher in the septic dogs, but their ability to oxidize FFA was comparable to that of themore » control dogs; therefore, the basal rate of FFA oxidation was higher in the septic dogs. These studies indicate that septic dogs have a decreased capacity to oxidize glucose, but that they retain their ability to oxidize long-chain fatty acids. Because the rate of lipolysis was increased in sepsis, lipid was the predominate energy substrate in this septic model.« less

Magnetic Nanoparticle-Based Imaging of RNA Transcripts in Breast Cancer Cells

DTIC Science & Technology

2008-06-30

control (Months 33 – 36). These studies have not yet commenced. KEY RESEARCH ACCOMPLISHMENTS: - Synthesized dextran-coated iron oxide NPs with...Size, charge, and concentration dependent uptake of iron oxide nanoparticles by non-phagocytic cells: a comparative study of USPIO, SSPIO, and MPIO...A. (2008) Size, charge, and concentration dependent uptake of iron oxide nanoparticles by non-phagocytic cells: a comparative study of USPIO, SSPIO

Thermodynamic Driving Force of Hydrogen on Rumen Microbial Metabolism: A Theoretical Investigation

PubMed Central

van Lingen, Henk J.; Plugge, Caroline M.; Fadel, James G.; Kebreab, Ermias; Bannink, André; Dijkstra, Jan

2016-01-01

Hydrogen is a key product of rumen fermentation and has been suggested to thermodynamically control the production of the various volatile fatty acids (VFA). Previous studies, however, have not accounted for the fact that only thermodynamic near-equilibrium conditions control the magnitude of reaction rate. Furthermore, the role of NAD, which is affected by hydrogen partial pressure (PH2), has often not been considered. The aim of this study was to quantify the control of PH2 on reaction rates of specific fermentation pathways, methanogenesis and NADH oxidation in rumen microbes. The control of PH2 was quantified using the thermodynamic potential factor (FT), which is a dimensionless factor that corrects a predicted kinetic reaction rate for the thermodynamic control exerted. Unity FT was calculated for all glucose fermentation pathways considered, indicating no inhibition of PH2 on the production of a specific type of VFA (e.g., acetate, propionate and butyrate) in the rumen. For NADH oxidation without ferredoxin oxidation, increasing PH2 within the rumen physiological range decreased FT from unity to zero for different NAD+ to NADH ratios and pH of 6.2 and 7.0, which indicates thermodynamic control of PH2. For NADH oxidation with ferredoxin oxidation, increasing PH2 within the rumen physiological range decreased FT from unity at pH of 7.0 only. For the acetate to propionate conversion, FT increased from 0.65 to unity with increasing PH2, which indicates thermodynamic control. For propionate to acetate and butyrate to acetate conversions, FT decreased to zero below the rumen range of PH2, indicating full thermodynamic suppression. For methanogenesis by archaea without cytochromes, FT differed from unity only below the rumen range of PH2, indicating no thermodynamic control. This theoretical investigation shows that thermodynamic control of PH2 on individual VFA produced and associated yield of hydrogen and methane cannot be explained without considering NADH oxidation. PMID:27783615

Evaluation of genotoxic and oxidative effects in workers exposed to jet propulsion fuel.

PubMed

Erdem, Onur; Sayal, Ahmet; Eken, Ayşe; Akay, Cemal; Aydın, Ahmet

2012-05-01

Jet fuel is a common occupational exposure risk among military and civilian populations. The purpose of this study was to evaluate genotoxic and oxidative effects in workers occupational exposure to jet propulsion fuel (JP-8). In this study, sister-chromatid exchange (SCE), high frequency of SCE cells (HFCs), and micronuclei (MN) were determined for 43 workers exposed to JP-8 and 38 control subjects. We measured the antioxidant enzyme activities including that of superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT). The levels of thiobarbituric acid-reactive substances (TBARS) were also studied. Urinary 1- and 2-naphthol excretion was used as a biomarker of occupational exposure to JP-8. The results obtained from cytogenetic analysis show a statistically significant increase in frequency of SCE in the exposed workers when compared to controls (P < 0.05). Interestingly, the mean value of the frequency (%o) of MN and HFCs for workers and controls did not show any statistical differences (P > 0.05). Oxidative stress parameters were not statistically different between exposed and control groups except for TBARS levels. Urinary 1-and 2-naphthol levels of exposed workers were found to be significantly higher than those of control subjects. Occupational exposure to JP-8 resulted in no significant genotoxic and oxidative effects, while smoking is the principal confounding factor for the some parameters. To understand the genotoxic and oxidative effects of JP-8 exposure, further studies should be planned to find out whether human populations may be at increased risk for cancer because of the exposures related to occupation and lifestyle.

Randomized controlled study of the safety and efficacy of nitrous oxide-sedated endoscopic ultrasound-guided fine needle aspiration for digestive tract diseases.

PubMed

Wang, Cai-Xia; Wang, Jian; Chen, Yuan-Yuan; Wang, Jia-Ni; Yu, Xin; Yang, Feng; Sun, Si-Yu

2016-12-14

To evaluate the efficacy and safety of nitrous oxide-sedated endoscopic ultrasound-guided fine needle aspiration. Enrolled patients were divided randomly into an experimental group (inhalation of nitrous oxide) and a control group (inhalation of pure oxygen) and heart rate, blood oxygen saturation, blood pressure, electrocardiogram (ECG) changes, and the occurrence of complications were monitored and recorded. All patients and physicians completed satisfaction questionnaires about the examination and scored the process using a visual analog scale. There was no significant difference in heart rate, blood oxygen saturation, blood pressure, ECG changes, or complication rate between the two groups of patients ( P > 0.05). However, patient and physician satisfaction were both significantly higher in the nitrous oxide compared with the control group ( P < 0.05). Nitrous oxide-sedation is a safe and effective option for patients undergoing endoscopic ultrasound-guided fine needle aspiration.

ALTERNATIVE OXIDANTS

EPA Science Inventory

This chapter reports on the efforts of the USEPA to study chloramines, chlorine dioxide and ozone as alternative oxidants/disinfectants to chlorine for the control of disinfection by-rpdocuts (DBPs) in drinking water. It examines the control of DBPs like trihalomethanes and haloa...

Redox status evaluation in dogs affected by mast cell tumour.

PubMed

Finotello, R; Pasquini, A; Meucci, V; Lippi, I; Rota, A; Guidi, G; Marchetti, V

2014-06-01

Oxidative stress status has been evaluated in depth in human medicine and its role in carcinogenesis has been clearly established. The purpose of this prospective study was to evaluate antioxidant concentrations and oxidative stress in dogs with mast cell tumours (MCTs) that had received no previous treatments, and to compare them to healthy controls. In 23 dogs with mast cell tumour and 10 healthy controls, oxidative status was assessed using the Reactive Oxygen Metabolites-derived compounds (d-ROMs) test, antioxidant activity was measured by the Biological Antioxidant Potential (BAP) test, and α-tocopherol levels were evaluated using high-performance liquid chromatography and ultraviolet analysis. At baseline, dogs with MCT had significantly higher d-ROMs (P < 0.00001) and lower BAP (P < 0.0002) compared with healthy controls. However, no significant difference was observed for α-tocopherol (P = 0.95). Results suggest that oxidative stress pattern and oxidative defence barrier are altered in dogs with newly diagnosed MCT compared with control dogs. Future studies are needed in order to assess the prognostic role of oxidative stress and to evaluate the impact of different therapeutic approaches. © 2012 John Wiley & Sons Ltd.

Diet supplementation during early lactation with non-alcoholic beer increases the antioxidant properties of breastmilk and decreases the oxidative damage in breastfeeding mothers.

PubMed

Codoñer-Franch, Pilar; Hernández-Aguilar, María T; Navarro-Ruiz, Almudena; López-Jaén, Ana B; Borja-Herrero, Cintia; Valls-Bellés, Victoria

2013-04-01

After delivery and birth, mothers and neonates are exposed to oxidative stress. We tested whether supplementing the diet of breastfeeding mothers with non-alcoholic beer, a product rich in antioxidants, could improve their oxidative status and the antioxidant content of their milk. A prospective trial begun on Day 2 postpartum was conducted in mother-infant dyads. Sixty breastfeeding mothers and their infants were allocated to either a control group (n=30) on a free diet or a study group (n=30) on a free diet supplemented with 660 mL of non-alcoholic beer/day. The oxidative status of the mothers' breastmilk, plasma, and urine and the infant's urine was analyzed on Days 2 and 30 postpartum. The before-after difference was compared within and between the groups. The increase in antioxidant capacity and coenzyme Q10 content in the breastmilk of the study group at Day 30 was higher than in that of the control group (p<0.001). There was also a change in the oxidative status of the mothers' plasma in the supplemented group regarding the control group; higher values of total antioxidant capacity (p<0.05) and lower levels of 8-hydroxydeoxyguanosine (p<0.05), indicative of DNA oxidative damage, were found. These results indicate a positive effect of non-alcoholic beer supplementation on oxidative stress in mothers. However, no difference in oxidant markers was found in the infant's urine. The consumption of non-alcoholic beer appears to enhance the antioxidant capacity of breastmilk and decrease oxidative damage in breastfeeding mothers.

Studies of protein oxidation as a product quality attribute on a scale-down model for cell culture process development.

PubMed

Lee, Nacole D; Kondragunta, Bhargavi; Uplekar, Shaunak; Vallejos, Jose; Moreira, Antonio; Rao, Govind

2015-01-01

Of importance to the biological properties of proteins produced in cell culture systems are the complex post-translational modifications that are affected by variations in process conditions. Protein oxidation, oxidative modification to intracellular proteins that involves cleavage of the polypeptide chain, and modifications of the amino acid side chains can be affected by such process variations. Dissolved oxygen is a parameter of increasing interest since studies have shown that despite the necessity of oxygen for respiration, there may also be some detrimental effects of oxygen to the cell. Production and accumulation of reactive oxygen species can cause damage to proteins as a result of oxidation of the cell and cellular components. Variation, or changes to cell culture products, can affect function, clearance rate, immunogenicity, and specific activity, which translates into clinical implications. The effect of increasing dissolved oxygen on protein oxidation in immunoglobulin G3-producing mouse hybridoma cells was studied using 50 mL high-throughput mini-bioreactors that employ non-invasive optical sensor technology for monitoring and closed feedback control of pH and dissolved oxygen. Relative protein carbonyl concentration of proteins produced under varying levels of dissolved oxygen was measured by enzyme-linked immunosorbent assay and used as an indicator of oxidative damage. A trend of increasing protein carbonyl content in response to increasing dissolved oxygen levels under controlled conditions was observed. Protein oxidation, oxidative modification to intracellular proteins that involves cleavage of the polypeptide chain, and modifications of the amino acid side chains can be affected by variations in dissolved oxygen levels in cell culture systems. Studies have shown that despite the necessity of oxygen for respiration, there may be detrimental effects of oxygen to the cell. Production and accumulation of reactive oxygen species can cause damage to proteins as a result of oxidation of the cell and cellular components, affecting function, clearance rate, immunogenicity, and specific activity, which translates into clinical implications. The effect of increasing dissolved oxygen on protein oxidation in immunoglobulin G3-producing mouse hybridoma cells was studied using 50 mL high-throughput mini-bioreactors that employ non-invasive optical sensor technology for monitoring and closed feedback control of pH and dissolved oxygen. Protein carbonyl concentration of proteins produced under varying levels of dissolved oxygen was measured by enzyme-linked immunosorbent assay and used as an indicator of oxidative damage. A trend of increasing protein carbonyl content in response to increasing dissolved oxygen levels under controlled conditions was observed. © PDA, Inc. 2015.

Oxidative stress biomarkers in pediatric sepsis: a prospective observational pilot study.

PubMed

Molina, Víctor; von Dessauer, Bettina; Rodrigo, Ramón; Carvajal, Cristian

2017-11-01

Oxidative stress is known to participate in the progression of sepsis. Definite data regarding the behavior of oxidative stress biomarkers in pediatric sepsis is still lacking. This study hypothesized that oxidative stress occurs in pediatric sepsis and that the magnitude of the redox derangement is associated with worse clinical progression. Forty-two previously healthy pediatric patients with sepsis and a group of control subjects were included. Oxidative stress and inflammatory activity biomarkers were determined in blood samples. Patients were prospectively followed until their discharge or death. Patients with non-severe and severe sepsis showed higher levels of plasmatic antioxidant capacity, lower erythrocyte thiol index, lower superoxide dismutase and catalase activities, higher glutathione peroxidase activity, and higher plasmatic F 2 -isoprostanes concentration than controls. Patients with severe sepsis had higher NF-kappaB activation than those with non-severe sepsis. Although we observed changes in some biomarkers in patients with worse clinical evolution, the explored biomarkers did not correlate with clinical estimators of outcome. Oxidative stress occurs in pediatric sepsis, resulting in oxidative damage. The explored biomarkers are not useful as outcome predictors in the studied population. The behavior of these biomarkers still needs to be addressed in broader groups of pediatric patients with sepsis.

Oxidative stress in schizophrenia: a case-control study on the effects on social cognition and neurocognition.

PubMed

Gonzalez-Liencres, Cristina; Tas, Cumhur; Brown, Elliot C; Erdin, Soner; Onur, Ece; Cubukcoglu, Zeynep; Aydemir, Omer; Esen-Danaci, Aysen; Brüne, Martin

2014-09-24

Schizophrenia is a debilitating mental disorder that presents impairments in neurocognition and social cognition. Several studies have suggested that the etiology of schizophrenia can be partly explained by oxidative stress. However, our knowledge about the implications of oxidative stress on illness-related cognitive deficits is still far from being clear. The aim of this work was to study the role of oxidative stress molecules on social cognition and neurocognition in patients with schizophrenia. We assessed the peripheral levels of several molecules associated with oxidative stress, namely nitric oxide (NO), malondialdehyde (MDA), glutathione (GSH), homocysteine, superoxide dismutase (SOD) and neurotrophin 4/5 (NT4/5), in forty-one patients with schizophrenia and forty-three healthy participants. A battery of tests to measure neurocognition and social cognition was also administered to the schizophrenia group. We found that the schizophrenia group presented substantially higher levels of oxidative stress than the control group, as revealed by elevated quantities of the pro-oxidants NO and MDA, and decreased levels of the antioxidants GSH, SOD and NT4/5. Interestingly, the levels of NT4/5, which have been shown to have antioxidant effects, correlated with executive functioning, as measured by two distinct tests (WCST and TMT). However, social cognition and symptom severity were not found to be associated with oxidative stress. We propose a protective role of NT4/5 against oxidative stress, which appears to have a potentially beneficial impact on neurocognition in schizophrenia.

Antioxidant defense and oxidative stress in children with acute hepatitis A

PubMed Central

Popovic-Dragonjic, Lidija; Jovanovic, Maja; Vrbic, Miodrag; Konstantinovic, Ljiljana; Kostic, Velimir; Dragonjic, Ivan

2011-01-01

BACKGROUND AND OBJECTIVES: Published data on oxidative stress in children with acute hepatitis A are still very scarce. This study aims to evaluate the oxidant/antioxidant status of these patients. DESIGN AND SETTING: Prospective, case-control study, over 2.5 years in patients under hospitalized and ambulatory care. PATIENTS AND METHODS: The levels of a whole-blood antioxidant, reduced glutathione; and plasma antioxidants, β-carotene, retinol, ascorbic acid, α-tocopherol; and the biomarker of oxidative stress, malondialdehyde, were evaluated in 50 pediatric patients (age range, 5-16 years; 29 males and 21 females) with acute hepatitis A and in 50 healthy children as control subjects (age range, 5-16 years; 25 males and 25 females). RESULTS: Plasma levels of reduced glutathione, β-carotene, retinol, α-tocopherol and ascorbic acid were significantly lower, while malondialdehyde plasma levels were significantly increased in the patient group when compared to the controls (P<.0001 for all parameters). CONCLUSIONS: Our findings show that pediatric patients with acute hepatitis A were influenced by oxidative stress, resulting in significantly lower levels of plasma antioxidants and increased lipid peroxidation. In the absence of other therapeutic options, antioxidant vitamin supplements could be added to the therapy for these patients to help reestablish the oxidant status balance. Further investigations to confirm this suggestion are recommended. PMID:21623054

Oxidants and anti-oxidants status in acne vulgaris patients with varying severity.

PubMed

Al-Shobaili, Hani A

2014-01-01

Acne vulgaris is a common dermatological disorder with a multifactorial pathogenesis. Oxidative status has been implicated in the pathogenesis of several skin diseases, including acne. This study was aimed to investigate the levels of oxidative stress biomarkers in acne vulgaris patients with varying severities. The study involved 156 patients with acne and 46 healthy human controls. Based on clinical examination, patients were grouped into 3 subgroups as follows: mild, moderate, and severe acne. Oxidative stress was examined by measuring plasma levels of catalase (CAT), superoxide dismutase (SOD), total antioxidant capacity (TAC), and malondialdehyde (MDA). Plasma levels of MDA in acne patients were significantly higher as compared with that of the controls, whereas activities of the antioxidant enzymes SOD and CAT were lower. Moreover, TAC was also low in acne patients as compared with that of the controls. Higher MDA levels in the severe acne subgroup as compared with that of the mild and moderate subgroups were also observed. Furthermore, in the severe acne subgroup, a significant negative correlation was observed between MDA and CAT levels. The data suggests that oxidative stress plays a key role in acne progress and may be employed as a biomarker index to assess the disease's activity and to monitor its treatment.

Impact of Oxidative Stress Biomarkers and Carboxymethyllysine (An Advanced Glycation End Product) on Prostate Cancer: A Prospective Study

PubMed Central

Yang, Shuman; Pinney, Susan M.; Mallick, Palash; Ho, Shuk-Mei; Bracken, Bruce; Wu, Tianying

2015-01-01

Introduction Biomarkers of oxidative stress and advanced glycation end products (AGE) have been linked to the development of prostate cancer, but evidence from human studies is either scarce or controversial. Materials and Methods We conducted a prospective nested case-control study among 48 men (24 prostate cancer cases and 24 controls) aged 48–76 years at baseline. The participants of our study were a part of the Fernald Community Cohort (FCC). Prostate cancer cases and controls were matched individually on age (± 3 years) with 1:1 ratio. Biomarkers included urine F2-isoprostanes (markers of lipid oxidation), plasma fluorescent oxidation products (FlOPs; markers of global oxidation) and carboxymethyllysine (CML; a major end-stage AGE). Results At baseline, cases had similar age, body mass index, proportion of family history of prostate cancer, history of benign prostatic hyperplasia, history of hypertension, history of diabetes, smokers and plasma glucose levels as compared to controls. Levels of plasma CML were significantly higher in cases than in controls (182 vs. 152 μg/ml, P < 0.05). In the conditional logistic regression model, an increase in CML equivalent to one standard deviation was associated with increased risk of incident prostate cancer (Relative risk = 1.79, 95% confidence interval = 1.00–3.21), and accounted for ~8% variance of prostate cancer liability. Urine F2-isoprostanes and plasma FlOPs were not associated with prostate cancer incidence. Conclusion Higher levels of plasma CML were associated with increased risk of prostate cancer. This suggests a potential new pathway for prostate cancer prediction and treatment. PMID:25972296

Effects of diet, packaging, and irradiation on protein oxidation, lipid oxidation, and color of raw broiler thigh meat during refrigerated storage.

PubMed

Xiao, S; Zhang, W G; Lee, E J; Ma, C W; Ahn, D U

2011-06-01

This study was designed to evaluate the effects of dietary treatment, packaging, and irradiation singly or in combination on the oxidative stability of broiler chicken thigh meat. A total of 120 four-week-old chickens were divided into 12 pens (10 birds/pen), and 4 pens of broilers were randomly assigned to a control oxidized diet (5% oxidized oil) or an antioxidant-added diet [500 IU of vitamin E + 200 mg/kg of butylated hydroxyanisole (BHA)] and fed for 2 wk. After slaughter, thigh meats were separated, ground, packaged in either oxygen-permeable or oxygen-impermeable vacuum bags, and irradiated at 0 or 3 kGy. Lipid oxidation (TBA-reactive substances), protein oxidation (carbonyl), and color of the meat were measured at 1, 4, and 7 d of refrigerated storage. The lipid and protein oxidation of thigh meats from birds fed the diet supplemented with antioxidants (vitamin E + BHA) was significantly lower than the lipid and protein oxidation of birds fed the control diet, whereas the lipid and protein oxidation of broilers fed the oxidized oil diet was higher than that of birds fed the control diet. Vacuum packaging slowed, but irradiation accelerated, the lipid and protein oxidation of thigh meat during storage. Dietary antioxidants (vitamin E + BHA) and irradiation treatments showed a stronger effect on lipid oxidation than on protein oxidation. A significant correlation between lipid and protein oxidation in meat was found during storage. Dietary supplementation of vitamin E + BHA and the irradiation treatment increased the lightness and redness of thigh meat, respectively. It is suggested that appropriate use of dietary antioxidants in combination with packaging could be effective in minimizing oxidative changes in irradiated raw chicken thigh meat.

40 CFR 52.1781 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Control strategy: Sulfur oxides and... Carolina § 52.1781 Control strategy: Sulfur oxides and particulate matter. (a) The plan's control strategy... State expects the resulting emission reductions of nitrogen oxides and sulfur dioxide from this control...

40 CFR 52.1781 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Control strategy: Sulfur oxides and... Carolina § 52.1781 Control strategy: Sulfur oxides and particulate matter. (a) The plan's control strategy... State expects the resulting emission reductions of nitrogen oxides and sulfur dioxide from this control...

40 CFR 52.1781 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Control strategy: Sulfur oxides and... Carolina § 52.1781 Control strategy: Sulfur oxides and particulate matter. (a) The plan's control strategy... State expects the resulting emission reductions of nitrogen oxides and sulfur dioxide from this control...

Substrate and nutrient limitation of ammonia-oxidizing bacteria and archaea in temperate forest soil

Treesearch

J.S. Norman; J.E. Barrett

2014-01-01

Ammonia-oxidizing microbes control the rate-limiting step of nitrification, a critical ecosystem process, which affects retention and mobility of nitrogen in soil ecosystems. This study investigated substrate (NH4þ) and nutrient (K and P) limitation of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in temperate forest soils at Coweeta Hydrologic...

Evaluation of Oxidative Stress in Bipolar Disorder in terms of Total Oxidant Status, Total Antioxidant Status, and Oxidative Stress Index

PubMed Central

CİNGİ YİRÜN, Merve; ÜNAL, Kübranur; ALTUNSOY ŞEN, Neslihan; YİRÜN, Onur; AYDEMİR, Çiğdem; GÖKA, Erol

2016-01-01

Introduction Bipolar disorder is one of the most debilitating psychiatric disorders characterized by disruptive episodes of mania/hypomania and depression. Considering the complex role of biological and environmental factors in the etiology of affective disorders, recent studies have focused on oxidative stress, which may damage nerve cell components and take part in pathophysiology. The aim of the present study was to contribute to the data about oxidative stress in bipolar disorder by detecting the total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) levels of manic episode (ME) and euthymic (EU) patients and by comparing these results with those of healthy controls (HCs). Methods The study population consisted of 28 EU outpatients meeting the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for bipolar disorder I and 23 inpatients who were currently hospitalized in a psychiatry ward with the diagnosis of the bipolar disorder ME according to the DSM-5 criteria. Forty-three healthy subjects were included in the study as the control group (HC). Serum TAS, TOS, and OSI levels of all the participants were determined. Results Statistical analysis of serum TAS, TOS, and OSI levels did not show any significant differences between the ME patients, EU patients, and HCs. Comparison between the bipolar disorder patients (ME+EU) and HC also did not reveal any statistically significant difference between these two groups in terms of serum TAS, TOS, and OSI levels. Conclusion To date, studies on oxidative stress in bipolar disorder have led to controversial results. In the present study, no statistically significant difference was detected between the oxidative parameters of bipolar disorder patients and HCs. In order to comprehensively evaluate oxidative stress in bipolar disorder, further studies are needed. PMID:28373794

Evaluation of Oxidative Stress in Bipolar Disorder in terms of Total Oxidant Status, Total Antioxidant Status, and Oxidative Stress Index.

PubMed

Cingi Yirün, Merve; Ünal, Kübranur; Altunsoy Şen, Neslihan; Yirün, Onur; Aydemir, Çiğdem; Göka, Erol

2016-09-01

Bipolar disorder is one of the most debilitating psychiatric disorders characterized by disruptive episodes of mania/hypomania and depression. Considering the complex role of biological and environmental factors in the etiology of affective disorders, recent studies have focused on oxidative stress, which may damage nerve cell components and take part in pathophysiology. The aim of the present study was to contribute to the data about oxidative stress in bipolar disorder by detecting the total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) levels of manic episode (ME) and euthymic (EU) patients and by comparing these results with those of healthy controls (HCs). The study population consisted of 28 EU outpatients meeting the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for bipolar disorder I and 23 inpatients who were currently hospitalized in a psychiatry ward with the diagnosis of the bipolar disorder ME according to the DSM-5 criteria. Forty-three healthy subjects were included in the study as the control group (HC). Serum TAS, TOS, and OSI levels of all the participants were determined. Statistical analysis of serum TAS, TOS, and OSI levels did not show any significant differences between the ME patients, EU patients, and HCs. Comparison between the bipolar disorder patients (ME+EU) and HC also did not reveal any statistically significant difference between these two groups in terms of serum TAS, TOS, and OSI levels. To date, studies on oxidative stress in bipolar disorder have led to controversial results. In the present study, no statistically significant difference was detected between the oxidative parameters of bipolar disorder patients and HCs. In order to comprehensively evaluate oxidative stress in bipolar disorder, further studies are needed.

Association of abdominal obesity, insulin resistance, and oxidative stress in adipose tissue in women with polycystic ovary syndrome.

PubMed

Chen, Li; Xu, Wen Ming; Zhang, Dan

2014-10-01

To study the expression of insulin signaling-related genes and oxidative stress markers in the visceral adipose tissue obtained from polycystic ovary syndrome (PCOS) patients and healthy control subjects and to investigate the relationships among abdominal obesity, insulin resistance, and oxidative stress at the tissue level. Case-control study. University teaching hospital. In total, 30 PCOS patients and 30 healthy control subjects, who underwent laparoscopic surgery, were included in the study. Abdominal obesity was defined based on waist circumference (WC). The homeostasis model index was used to assess insulin resistance (HOMA-IR). Gene expression of glucose transporter 4 (GLUT4) and insulin receptor substrate 1 (IRS1) in visceral adipose tissue (VAT) and the parameters of oxidative stress, such as superoxide dismutase, enzyme glutathione reductase, and dimethylarginine, were measured, and the expression of protein oxidative damage product 3-nitro-tyrosine residues (nitrotyrosine) in VAT was identified with the use of immunohistochemistry. PCOS was associated with lower expression of GLUT4 and IRS1 and a higher level of oxidative stress in VAT, which was strongly correlated with WC and HOMA-IR. Presence of abdominal obesity further intensified the correlations observed in our measurements. The nitrotyrosine expression in VAT was stronger in PCOS patients. The strong correlation of insulin resistance with oxidative stress at the VAT level suggests that local oxidative stress and abnormalities of insulin signaling in adipose tissue play critical roles in the pathogenesis of PCOS. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

SOD2 deficiency in hematopoietic cells in mice results in reduced red blood cell deformability and increased heme degradation

PubMed Central

Mohanty, Joy G.; Nagababu, Enika; Friedman, Jeffrey S.; Rifkind, Joseph M.

2013-01-01

Among the three types of super oxide dismutases (SODs) known, SOD2 deficiency is lethal in neonatal mice owing to cardiomyopathy caused by severe oxidative damage. SOD2 is found in red blood cell (RBC) precursors, but not in mature RBCs. To investigate the potential damage to mature RBCs resulting from SOD2 deficiency in precursor cells, we studied RBCs from mice in which fetal liver stem cells deficient in SOD2 were capable of efficiently rescuing lethally irradiated host animals. These transplanted animals lack SOD2 only in hematopoietically generated cells and live longer than SOD2 knockouts. In these mice, approximately 2.8% of their total RBCs in circulation are iron-laden reticulocytes, with numerous siderocytic granules and increased protein oxidation similar to that seen in sideroblastic anemia. We have studied the RBC deformability and oxidative stress in these animals and the control group by measuring them with a microfluidic ektacytometer and assaying fluorescent heme degradation products with a fluorimeter, respectively. In addition, the rate of hemoglobin oxidation in RBCs from these mice and the control group were measured spectrophotometrically. The results show that RBCs from these SOD2-deficient mice have reduced deformability, increased heme degradation products, and an increased rate of hemoglobin oxidation compared with control animals, indicative of increased RBC oxidative stress. PMID:23142655

Controllable film densification and interface flatness for high-performance amorphous indium oxide based thin film transistors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ou-Yang, Wei, E-mail: OUYANG.Wei@nims.go.jp, E-mail: TSUKAGOSHI.Kazuhito@nims.go.jp; Mitoma, Nobuhiko; Kizu, Takio

2014-10-20

To avoid the problem of air sensitive and wet-etched Zn and/or Ga contained amorphous oxide transistors, we propose an alternative amorphous semiconductor of indium silicon tungsten oxide as the channel material for thin film transistors. In this study, we employ the material to reveal the relation between the active thin film and the transistor performance with aid of x-ray reflectivity study. By adjusting the pre-annealing temperature, we find that the film densification and interface flatness between the film and gate insulator are crucial for achieving controllable high-performance transistors. The material and findings in the study are believed helpful for realizingmore » controllable high-performance stable transistors.« less

The possibility of multi-layer nanofabrication via atomic force microscope-based pulse electrochemical nanopatterning

NASA Astrophysics Data System (ADS)

Kim, Uk Su; Morita, Noboru; Lee, Deug Woo; Jun, Martin; Park, Jeong Woo

2017-05-01

Pulse electrochemical nanopatterning, a non-contact scanning probe lithography process using ultrashort voltage pulses, is based primarily on an electrochemical machining process using localized electrochemical oxidation between a sharp tool tip and the sample surface. In this study, nanoscale oxide patterns were formed on silicon Si (100) wafer surfaces via electrochemical surface nanopatterning, by supplying external pulsed currents through non-contact atomic force microscopy. Nanoscale oxide width and height were controlled by modulating the applied pulse duration. Additionally, protruding nanoscale oxides were removed completely by simple chemical etching, showing a depressed pattern on the sample substrate surface. Nanoscale two-dimensional oxides, prepared by a localized electrochemical reaction, can be defined easily by controlling physical and electrical variables, before proceeding further to a layer-by-layer nanofabrication process.

The effect of upper gastrointestinal system endoscopy process on serum oxidative stress levels.

PubMed

Turan, Mehmet Nuri; Aslan, Mehmet; Bolukbas, Filiz Fusun; Bolukbas, Cengiz; Selek, Sahbettin; Sabuncu, Tevfik

2016-12-01

Some authors have investigated the effects of oxidative stress in some process such as undergoing laparoscopic. However, the effect of upper gastrointestinal system endoscopy process on oxidative stress is unclear. We evaluated the short-term effect of upper gastrointestinal system endoscopy process on oxidative stress. Thirty patients who underwent endoscopy process and 20 healthy controls were enrolled in the prospective study. Serum total antioxidant capacity and total oxidant status measurements were measured before and after endoscopy process. The ratio percentage of total oxidant status to total antioxidant capacity was regarded as oxidative stress index. Before endoscopy process, serum total antioxidant capacity levels were higher, while serum total oxidant status levels and oxidative stress index values were lower in patients than controls, but this difference was not statistically significant (all, p > 0.05). After endoscopy process, serum total antioxidant capacity and total oxidant status levels were significantly higher in patients than before endoscopy process (both, p < 0.05). However, oxidative stress index values were slight higher in patients but this difference was not statistically significant (p > 0.05). We observed that serum TAC and TOS levels were increased in patients who underwent endoscopy process after endoscopy process. However, short-time upper gastrointestinal system endoscopy process did not cause an important change in the oxidative stress index. Further studies enrolling a larger number of patients are required to clarify the results obtained here.

Supercritical water oxidation of products of human metabolism

NASA Technical Reports Server (NTRS)

Tester, Jefferson W.; Orge A. achelling, Richard K. ADTHOMASSON; Orge A. achelling, Richard K. ADTHOMASSON

1986-01-01

Although the efficient destruction of organic material was demonstrated in the supercritical water oxidation process, the reaction kinetics and mechanisms are unknown. The kinetics and mechanisms of carbon monoxide and ammonia oxidation in and reaction with supercritical water were studied experimentally. Experimental oxidation of urine and feces in a microprocessor controlled system was performed. A minaturized supercritical water oxidation process for space applications was design, including preliminary mass and energy balances, power, space and weight requirements.

Oxidation Induced Doping of Nanoparticles Revealed by in Situ X-ray Absorption Studies.

PubMed

Kwon, Soon Gu; Chattopadhyay, Soma; Koo, Bonil; Dos Santos Claro, Paula Cecilia; Shibata, Tomohiro; Requejo, Félix G; Giovanetti, Lisandro J; Liu, Yuzi; Johnson, Christopher; Prakapenka, Vitali; Lee, Byeongdu; Shevchenko, Elena V

2016-06-08

Doping is a well-known approach to modulate the electronic and optical properties of nanoparticles (NPs). However, doping at nanoscale is still very challenging, and the reasons for that are not well understood. We studied the formation and doping process of iron and iron oxide NPs in real time by in situ synchrotron X-ray absorption spectroscopy. Our study revealed that the mass flow of the iron triggered by oxidation is responsible for the internalization of the dopant (molybdenum) adsorbed at the surface of the host iron NPs. The oxidation induced doping allows controlling the doping levels by varying the amount of dopant precursor. Our in situ studies also revealed that the dopant precursor substantially changes the reaction kinetics of formation of iron and iron oxide NPs. Thus, in the presence of dopant precursor we observed significantly faster decomposition rate of iron precursors and substantially higher stability of iron NPs against oxidation. The same doping mechanism and higher stability of host metal NPs against oxidation was observed for cobalt-based systems. Since the internalization of the adsorbed dopant at the surface of the host NPs is driven by the mass transport of the host, this mechanism can be potentially applied to introduce dopants into different oxidized forms of metal and metal alloy NPs providing the extra degree of compositional control in material design.

Visualization of Oxidative Stress Induced by Experimental Periodontitis in Keap1-Dependent Oxidative Stress Detector-Luciferase Mice.

PubMed

Kataoka, Kota; Ekuni, Daisuke; Tomofuji, Takaaki; Irie, Koichiro; Kunitomo, Muneyoshi; Uchida, Yoko; Fukuhara, Daiki; Morita, Manabu

2016-11-16

The aim of this study was to investigate whether a Keap1-dependent oxidative stress detector-luciferase (OKD-LUC) mouse model would be useful for the visualization of oxidative stress induced by experimental periodontitis. A ligature was placed around the mandibular first molars for seven days to induce periodontitis. Luciferase activity was measured with an intraperitoneal injection of d-luciferin on days 0, 1, and 7. The luciferase activity in the periodontitis group was significantly greater than that in the control group at seven days. The expressions of heme oxygenase-1 (HO-1) and malondialdehyde in periodontal tissue were significantly higher in the periodontitis group than in the control group. Immunofluorescent analysis confirmed that the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) occurred more frequently in the periodontitis group than in the control group. This study found that under oxidative stress induced by experimental periodontitis, the Nrf2/antioxidant defense pathway was activated and could be visualized from the luciferase activity in the OKD-LUC model. Thus, the OKD-LUC mouse model may be useful for exploring the mechanism underlying the relationship between the Nrf2/antioxidant defense pathway and periodontitis by enabling the visualization of oxidative stress over time.

Erythrocyte deformability and oxidative stress in inflammatory bowel disease.

PubMed

Akman, Tulay; Akarsu, Mesut; Akpinar, Hale; Resmi, Halil; Taylan, Ebru; Sezer, Ebru

2012-02-01

Oxidative stress and reduced microvascular flow are important factors in the pathogenesis of inflammatory bowel disease (IBD). The increased oxidative stress reduces the erythrocyte deformability. However, in IBD, there are no studies in the literature which evaluate erythrocyte deformability. In our study, we investigated the effect of oxidative stress and erythrocyte deformability in IBD. Forty-three patients with active IBD, 48 patients with inactive IBD and 45 healthy controls were included. The erytrocyte deformability, malonyldialdehyde levels, glutation peroxidase and sulfhydryl levels were measured in peripheral venous blood samples. Erytrocyte malonyldialdehyde levels in both active and inactive IBD were significantly increased compared with control groups. Plasma glutation peroxidase levels did not show statistically significant difference between all groups. The decreased plasma sulfhydryl levels in active IBD were statistically significant compared with both the inactive IBD and the control group, but plasma sulfhydryl levels in inactive IBD group did not show statistically significant differences when compared with the control group. Elongation index values in both active and inactive IBD increased significantly compared with the control group. Statistically significant correlations were not found between the elongation index and glutation peroxidase, malonyldialdehyde, sulfhydryl levels in all groups. Our study is the first to evaluate the erythrocyte deformability in IBD. In our study, increased erytrocyte malonyldialdehyde levels and decreased plasma sulfhydryl levels manifested the role of oxidative stress in the pathogenesis of the disease. It is thought that the increased erythrocyte malonyldialdehyde values cause the reduction in erythrocyte deformability.

Is fibromyalgia-related oxidative stress implicated in the decline of physical and mental health status?

PubMed

La Rubia, Mercedes; Rus, Alma; Molina, Francisco; Del Moral, M Luisa

2013-01-01

Fibromyalgia (FM) is a form of non-articular rheumatism characterised by chronic widespread musculoskeletal aching. Although some works have investigated the possible role of oxidative stress in the pathophysiology of FM, none has analysed a significant number of oxidative markers in the same patients. Consequently, we have performed an exhaustive study of the oxidative/antioxidative status in FM patients and healthy controls, as well as the relationship with FM clinical parameters. In 45 female patients and 25 age-matched controls, we investigated the oxidative (lipid and protein peroxidation, and oxidative DNA damage) and antioxidative status (total antioxidant capacity (TAC), and antioxidant enzyme activities and compounds). Functional capacity and musculoskeletal pain were assessed by Fibromyalgia Impact Questionnaire (FIQ) and Visual Analogue Scale (VAS), respectively. The physical (PCS-12) and mental (MCS-12) health status was evaluated by SF-12. A significant increase in oxidative DNA damage and protein carbonyl content was found in FM patients vs. controls, as well as in antioxidant compounds such as copper and ceruloplasmin. Patients had diminished levels of TAC and zinc. Enzyme activities of superoxide dismutase, glutathione peroxidase, and catalase were lower in FM patients. Significant correlations were observed in patients between oxidative DNA damage and MCS-12, and zinc and PCS-12. These findings reveal an imbalance between oxidants and antioxidants in FM patients. The lower antioxidant enzyme activities may lead to oxidative stress through the oxidation of DNA and proteins, which may affect the health status of FM patients.

Oxidative stress and myeloperoxidase levels in saliva of patients with recurrent aphthous stomatitis.

PubMed

Cağlayan, F; Miloglu, O; Altun, O; Erel, O; Yilmaz, A B

2008-11-01

Recurrent aphthous stomatitis (RAS) is the most common oral ulcerative condition affecting 5-25% of the general population. The aim of this study was to evaluate the oxidative stress parameters in saliva of patients with RAS and to investigate the relationship among these parameters in either group. The study involved 50 patients with RAS of whom 24 were male and 26 were female, and 25 healthy controls of whom 13 were male and 12 were female. There was no statistically significant difference in the salivary total antioxidant capacity, total oxidant status, oxidative stress index levels, and myeloperoxidase activity between patients with RAS and those in the control group. The results show that reactive oxygen species may not play a role in the etiology of RAS.

40 CFR 52.278 - Oxides of nitrogen control.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Oxides of nitrogen control. 52.278... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.278 Oxides of nitrogen control. (a) The following regulations are disapproved because they relax the control of nitrogen oxides...

40 CFR 52.278 - Oxides of nitrogen control.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Oxides of nitrogen control. 52.278... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.278 Oxides of nitrogen control. (a) The following regulations are disapproved because they relax the control of nitrogen oxides...

40 CFR 52.278 - Oxides of nitrogen control.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Oxides of nitrogen control. 52.278... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.278 Oxides of nitrogen control. (a) The following regulations are disapproved because they relax the control of nitrogen oxides...

40 CFR 52.278 - Oxides of nitrogen control.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Oxides of nitrogen control. 52.278... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.278 Oxides of nitrogen control. (a) The following regulations are disapproved because they relax the control of nitrogen oxides...

Serum Paraoxonase 1 Activity and Oxidative Stress in Pediatric Patients with Pulmonary Tuberculosis

PubMed Central

Torun, Emel; Gedik, Ahmet Hakan; Cakir, Erkan; Umutoglu, Tarik; Gok, Ozlem; Kilic, Ulkan

2014-01-01

Objectives The aim of this study was to determine the oxidative stress and paraoxonase 1 (PON1) levels in children with pulmonary tuberculosis (TB) compared to healthy controls, and to examine the association of demographical with oxidative stress. Subjects and Methods Forty children diagnosed with pulmonary TB and 40 age- and gender-matched healthy controls were enrolled in the study. Serum total antioxidant status (TAS), total oxidant status (TOS) and PON1 levels were measured. The oxidative stress index (OSI) was calculated to indicate the degree of oxidative stress. Results The TAS levels were lower (1.73 ± 0.5 vs. 2.54 ± 1.2 μmol Trolox Eq/l) while TOS levels were significantly higher (26.9 ± 14.4 vs. 13.4 ± 7.7 μmol H2O2 Eq/l) in the TB group than in the controls (p < 0.001). The OSI was significantly higher in the TB group than in the controls (21.2 ± 5.1 vs. 6.5 ± 4.9 units, p = 0.006). Serum PON1 levels were significantly lower in the TB group than in the controls (14.2 ± 13.2 vs. 28.4 ± 17.3 U/l, p < 0.001). The lower PON1 levels correlated with TAS and OSI levels but not with anthropometric parameters (r = 0.264, p = 0.018 and r = −0.255, p = 0.023, respectively). Conclusion The TOS and OSI levels were higher and the TAS and PON1 levels were lower in pediatric patients with pulmonary TB when compared to healthy controls. This indicates greater oxidative stress in the patients. PMID:25034194

Oxidation and Hydration of U 3O 8 Materials Following Controlled Exposure to Temperature and Humidity

DOE PAGES

Tamasi, Alison L.; Boland, Kevin S.; Czerwinski, Kenneth; ...

2015-03-18

Chemical signatures correlated with uranium oxide processing are of interest to forensic science for inferring sample provenance. Identification of temporal changes in chemical structures of process uranium materials as a function of controlled temperatures and relative humidities may provide additional information regarding sample history. In our study, a high-purity α-U 3O 8 sample and three other uranium oxide samples synthesized from reaction routes used in nuclear conversion processes were stored under controlled conditions over 2–3.5 years, and powder X-ray diffraction analysis and X-ray absorption spectroscopy were employed to characterize chemical speciation. We measured signatures from the α-U 3O 8 samplemore » indicated that the material oxidized and hydrated after storage under high humidity conditions over time. Impurities, such as uranyl fluoride or schoepites, were initially detectable in the other uranium oxide samples. After storage under controlled conditions, the analyses of the samples revealed oxidation over time, although the signature of the uranyl fluoride impurity diminished. The presence of schoepite phases in older uranium oxide material is likely indicative of storage under high humidity and should be taken into account for assessing sample history. Finally, the absence of a signature from a chemical impurity, such as uranyl fluoride hydrate, in an older material may not preclude its presence at the initial time of production.« less

Oxidation and Hydration of U 3 O 8 Materials Following Controlled Exposure to Temperature and Humidity

DOE PAGES

Tamasi, Alison L.; Boland, Kevin S.; Czerwinski, Kenneth; ...

2015-03-18

Chemical signatures correlated with uranium oxide processing are of interest to forensic science for inferring sample provenance. Identification of temporal changes in chemical structures of process uranium materials as a function of controlled temperatures and relative humidities may provide additional information regarding sample history. In our study, a high-purity α-U 3O 8 sample and three other uranium oxide samples synthesized from reaction routes used in nuclear conversion processes were stored under controlled conditions over 2–3.5 years, and powder X-ray diffraction analysis and X-ray absorption spectroscopy were employed to characterize chemical speciation. We measured signatures from the α-U 3O 8 samplemore » indicated that the material oxidized and hydrated after storage under high humidity conditions over time. Impurities, such as uranyl fluoride or schoepites, were initially detectable in the other uranium oxide samples. After storage under controlled conditions, the analyses of the samples revealed oxidation over time, although the signature of the uranyl fluoride impurity diminished. The presence of schoepite phases in older uranium oxide material is likely indicative of storage under high humidity and should be taken into account for assessing sample history. Finally, the absence of a signature from a chemical impurity, such as uranyl fluoride hydrate, in an older material may not preclude its presence at the initial time of production. LA-UR-15-21495.« less

Sex-dependent effects of high-fat-diet feeding on rat pancreas oxidative stress.

PubMed

Gómez-Pérez, Yolanda; Gianotti, Magdalena; Lladó, Isabel; Proenza, Ana M

2011-07-01

The objective of the study was to investigate whether sex differences in oxidative stress-associated insulin resistance previously reported in rats could be attributed to a possible sex dimorphism in pancreas redox status. Fifteen-month-old male and female Wistar rats were fed a control diet or a high-fat diet for 14 weeks. Serum glucose, lipids, and hormone levels were measured. Insulin immunohistochemistry and morphometric analysis of islets were performed. Pancreas triglyceride content, oxidative damage, and antioxidant enzymatic activities were determined. Lipoprotein lipase, hormone-sensitive lipase, and uncoupling protein 2 (UCP2) levels were also measured. Male rats showed a more marked insulin resistance profile than females. In control female rats, pancreas Mn-superoxide dismutase activity and UCP2 levels were higher, and oxidative damage was lower compared with males. High-fat-diet feeding decreased pancreas triglyceride content in female rats and UCP2 levels in male rats. High-fat-diet female rats showed larger islets than both their control and sex counterparts. These results confirm the existence of a sex dimorphism in pancreas oxidative status in both control and high-fat-diet feeding situations, with female rats showing higher protection against oxidative stress, thus maintaining pancreatic function and contributing to a lower risk of insulin resistance.

Investigation of selective catalytic reduction impact on mercury speciation under simulated NOx emission control conditions.

PubMed

Lee, Chun W; Srivastava, Ravi K; Ghorishi, S Behrooz; Hastings, Thomas W; Stevens, Frank M

2004-12-01

Selective catalytic reduction (SCR) technology increasingly is being applied for controlling emissions of nitrogen oxides (NOx) from coal-fired boilers. Some recent field and pilot studies suggest that the operation of SCR could affect the chemical form of mercury (Hg) in coal combustion flue gases. The speciation of Hg is an important factor influencing the control and environmental fate of Hg emissions from coal combustion. The vanadium and titanium oxides, used commonly in the vanadia-titania SCR catalyst for catalytic NOx reduction, promote the formation of oxidized mercury (Hg2+). The work reported in this paper focuses on the impact of SCR on elemental mercury (Hg0) oxidation. Bench-scale experiments were conducted to investigate Hg0 oxidation in the presence of simulated coal combustion flue gases and under SCR reaction conditions. Flue gas mixtures with different concentrations of hydrogen chloride (HCl) and sulfur dioxide (SO2) for simulating the combustion of bituminous coals and subbituminous coals were tested in these experiments. The effects of HCl and SO2 in the flue gases on Hg0 oxidation under SCR reaction conditions were studied. It was observed that HCl is the most critical flue gas component that causes conversion of Hg0 to Hg2+ under SCR reaction conditions. The importance of HCl for Hg0 oxidation found in the present study provides the scientific basis for the apparent coal-type dependence observed for Hg0 oxidation occurring across the SCR reactors in the field.

Low nourishment of B-vitamins is associated with hyperhomocysteinemia and oxidative stress in newly diagnosed cardiac patients.

PubMed

Waly, Mostafa I; Ali, Amanat; Al-Nassri, Amira; Al-Mukhaini, Mohamed; Valliatte, John; Al-Farsi, Yahya

2016-01-01

We are currently witnessing a dramatic change in lifestyle and food choices that is accompanied with an increase in the rate of morbidity and mortality from cardiovascular diseases (CVD). Although studies have reported an association of CVD with hyperhomocysteinemia-mediated oxidative stress, the biochemical basis is not known. This case-control study was aimed to evaluate the nutritional and biochemical status of B-vitamins in relation to hyperhomocysteinemia and oxidative stress in newly diagnosed cardiac patients. The retrospective dietary intake of the study subjects (cases and controls) was estimated using a semi-quantitative food frequency questionnaire, and fasting blood samples were drawn to assess their serum levels of B-vitamins (folate, vitamins B6 and B12), homocysteine (HCY), and oxidative stress indices such as glutathione (GSH), total antioxidant capacity (TAC), malondialdehyde (MDA), and nitrites and nitrates (NN). It was observed that the cases had a lower dietary intake of B-vitamins as compared to their matched control subjects as well as to the corresponding recommended dietary allowances. Biochemical analysis of cases, as compared to controls, indicated depletion of GSH, impairment of TAC, and an elevation in the serum levels of HCY, MDA, and NN. These results suggest that lower status (dietary intake and serum levels) of B-vitamins is involved in the etiology of hyperhomocysteinemia and oxidative stress, the typical risk factors for CVD. © 2016 by the Society for Experimental Biology and Medicine.

Increased oxidative stress in preschool children exposed to passive smoking.

PubMed

Yıldırım, Faruk; Sermetow, Kabil; Aycicek, Ali; Kocyigit, Abdurrahim; Erel, Ozcan

2011-01-01

To study the effect of passive cigarette smoking on plasma oxidative and antioxidative status in passive smoking preschool children and to compare them with controls. Thirty-four passive smoking (five to 50 cigarettes per day) preschool children (study group) and 32 controls who had never been exposed to cigarette smoke were randomly chosen from children aged from 4 to 6 years. Urinary cotinine and plasma indicators of oxidative and antioxidative status, i.e., total oxidant status (TOS), total antioxidant capacity (TAC), and oxidative stress index (OSI), were determined. Mean environmental cigarette consumption was 22±13 cigarettes per day in passive smoking children. Mean urinary cotinine levels were 77.6±41.4 ng/mL and 11.9±2.3 ng/mL in the study and control groups, respectively (p < 0.001). Mean plasma TAC levels were 0.95±0.13 mmol Trolox equivalent/L and 1.01±0.09 mmol Trolox equivalent/L, respectively (p = 0.039). Mean plasma TOS levels were 28.6±7.9 µmol H2O2 equivalent/L and 18.5±6.3 µmol H2O2 equivalent/L, respectively (p < 0.001). Mean OSI levels were 3.08±0.98 arbitrary units and 1.84±0.64 arbitrary units, respectively (p < 0.001). A small amount of cigarette smoke (five to 10 cigarettes per day) causes considerable oxidative stress. There were significant correlations between number of cigarettes consumed and oxidant status and OSI levels. Passive smoke is a potent oxidant in preschool children. Its deleterious effects are not limited just to heavy passive smoking, but also occur with exposure to small amounts of smoke.

Thorium binding by biochar fibres derived from Luffa Cylindrica after controlled surface oxidation

NASA Astrophysics Data System (ADS)

Liatsou, Ioanna; Christodoulou, Eleni; Paschalidis, Ioannis

2017-04-01

Controlled surface modification of biochar fibres derived from Luffa Cylindrica sponges has been carried out by nitric acid and the degree of oxidation could be controlled by changing the acid concentration or the reaction time. The extent of surface oxidation has been quantified by acid-base titration and FTIR-spectroscopy. Furthermore, thorium binding has been studied as a function of various parameters and the experimental results show that even under strong acidic conditions the relative sorption is above 70% and the sorption capacity of the biochar fibres for Th(IV) at pH 3 is qmax= 70 gṡkg-1.

Randomized controlled study of the safety and efficacy of nitrous oxide-sedated endoscopic ultrasound-guided fine needle aspiration for digestive tract diseases

PubMed Central

Wang, Cai-Xia; Wang, Jian; Chen, Yuan-Yuan; Wang, Jia-Ni; Yu, Xin; Yang, Feng; Sun, Si-Yu

2016-01-01

AIM To evaluate the efficacy and safety of nitrous oxide-sedated endoscopic ultrasound-guided fine needle aspiration. METHODS Enrolled patients were divided randomly into an experimental group (inhalation of nitrous oxide) and a control group (inhalation of pure oxygen) and heart rate, blood oxygen saturation, blood pressure, electrocardiogram (ECG) changes, and the occurrence of complications were monitored and recorded. All patients and physicians completed satisfaction questionnaires about the examination and scored the process using a visual analog scale. RESULTS There was no significant difference in heart rate, blood oxygen saturation, blood pressure, ECG changes, or complication rate between the two groups of patients (P > 0.05). However, patient and physician satisfaction were both significantly higher in the nitrous oxide compared with the control group (P < 0.05). CONCLUSION Nitrous oxide-sedation is a safe and effective option for patients undergoing endoscopic ultrasound-guided fine needle aspiration. PMID:28028373

Increased 5S rRNA oxidation in Alzheimer's disease.

PubMed

Ding, Qunxing; Zhu, Haiyan; Zhang, Bing; Soriano, Augusto; Burns, Roxanne; Markesbery, William R

2012-01-01

It is widely accepted that oxidative stress is involved in neurodegenerative disorders such as Alzheimer's disease (AD). Ribosomal RNA (rRNA) is one of the most abundant molecules in most cells and is affected by oxidative stress in the human brain. Previous data have indicated that total rRNA levels were decreased in the brains of subjects with AD and mild cognitive impairment concomitant with an increase in rRNA oxidation. In addition, level of 5S rRNA, one of the essential components of the ribosome complex, was significantly lower in the inferior parietal lobule (IP) brain area of subjects with AD compared with control subjects. To further evaluate the alteration of 5S rRNA in neurodegenerative human brains, multiple brain regions from both AD and age-matched control subjects were used in this study, including IP, superior and middle temporal gyro, temporal pole, and cerebellum. Different molecular pools including 5S rRNA integrated into ribosome complexes, free 5S rRNA, cytoplasmic 5S rRNA, and nuclear 5S rRNA were studied. Free 5S rRNA levels were significantly decreased in the temporal pole region of AD subjects and the oxidation of ribosome-integrated and free 5S rRNA was significantly increased in multiple brain regions in AD subjects compared with controls. Moreover, a greater amount of oxidized 5S rRNA was detected in the cytoplasm and nucleus of AD subjects compared with controls. These results suggest that the increased oxidation of 5S rRNA, especially the oxidation of free 5S rRNA, may be involved in the neurodegeneration observed in AD.

In vivo oxidation in remelted highly cross-linked retrievals.

PubMed

Currier, B H; Van Citters, D W; Currier, J H; Collier, J P

2010-10-20

Elimination of free radicals to prevent oxidation has played a major role in the development and product differentiation of the latest generation of highly cross-linked ultra-high molecular weight polyethylene bearing materials. In the current study, we (1) examined oxidation in a series of retrieved remelted highly cross-linked ultra-high molecular weight polyethylene bearings from a number of device manufacturers and (2) compared the retrieval results with findings for shelf-stored control specimens. The hypothesis was that radiation-cross-linked remelted ultra-high molecular weight polyethylene would maintain oxidative stability in vivo comparable with the stability during shelf storage and in published laboratory aging tests. Fifty remelted highly cross-linked ultra-high molecular weight polyethylene acetabular liners and nineteen remelted highly cross-linked ultra-high molecular weight polyethylene tibial inserts were received after retrieval from twenty-one surgeons from across the U.S. Thirty-two of the retrievals had been in vivo for two years or more. Each was measured for oxidation with use of Fourier transform infrared spectroscopy. A control series of remelted highly cross-linked ultra-high molecular weight polyethylene acetabular liners from three manufacturers was analyzed with electron paramagnetic resonance spectroscopy to measure free radical content and with Fourier transform infrared spectroscopy to measure oxidation initially and after eight to nine years of shelf storage in air. The never-implanted, shelf-aged controls had no measurable free-radical content initially or after eight to nine years of shelf storage. The never-implanted controls showed no increase in oxidation during shelf storage. Oxidation measurements showed measurable oxidation in 22% of the retrieved remelted highly cross-linked liners and inserts after an average of two years in vivo. Because never-implanted remelted highly cross-linked ultra-high molecular weight polyethylene materials had no measurable free-radical concentration and no increase in oxidation during shelf storage, these materials were expected to be oxidation-resistant in vivo. However, some remelted highly cross-linked ultra-high molecular weight polyethylene retrievals showed measurable oxidation after an average of more than two years in vivo. This apparent departure from widely expected behavior requires continued study of the process of in vivo oxidation of ultra-high molecular weight polyethylene materials.

Increased oxidative stress and its relation with collagen metabolism in knee osteoarthritis.

PubMed

Altindag, Ozlem; Erel, Ozcan; Aksoy, Nurten; Selek, Sahabettin; Celik, Hakim; Karaoglanoglu, Mustafa

2007-02-01

The purpose of this study was to determine serum oxidative/antioxidative status in patients with knee osteoarthritis and its relation with prolidase activity, which plays an important role in collagen metabolism. Serum antioxidative status was evaluated by measuring total antioxidant capacity (TAC), thiol level and catalase enzyme activity in patients with osteoarthritis and in healthy controls. Serum oxidative status was evaluated by measuring total peroxide (TP) and lipid hydroperoxide. Oxidative stress index (OSI) was calculated. Prolidase enzyme activity was measured to investigate the collagen metabolism. Serum TAC, thiol level, catalase activity and prolidase activity were significantly lower in patients than in controls (P < 0.001, for all). In contrast, TP, lipid hydroperoxide and OSI values were significantly higher in patients than in controls (P < 0.001 for all). Further, prolidase activity was negatively correlated with TP and OSI, and positively correlated with TAC. The present results indicate that the oxidant parameters increased and antioxidant parameters decreased in patients with osteoarthritis; therefore, these patients may be exposed to a potent oxidative stress. Decreased collagen metabolism may be related with oxidative stress, which has a role in the ethiopathogenesis and/or in the progression of the disease.

Highly stable field emission from ZnO nanowire field emitters controlled by an amorphous indium–gallium–zinc-oxide thin film transistor

NASA Astrophysics Data System (ADS)

Li, Xiaojie; Wang, Ying; Zhang, Zhipeng; Ou, Hai; She, Juncong; Deng, Shaozhi; Xu, Ningsheng; Chen, Jun

2018-04-01

Lowering the driving voltage and improving the stability of nanowire field emitters are essential for them to be applied in devices. In this study the characteristics of zinc oxide (ZnO) nanowire field emitter arrays (FEAs) controlled by an amorphous indium–gallium–zinc-oxide thin film transistor (a-IGZO TFT) were studied. A low driving voltage along with stabilization of the field emission current were achieved. Modulation of field emission currents up to three orders of magnitude was achieved at a gate voltage of 0–32 V for a constant anode voltage. Additionally, a-IGZO TFT control can dramatically reduce the emission current fluctuation (i.e., from 46.11 to 1.79% at an emission current of ∼3.7 µA). Both the a-IGZO TFT and ZnO nanowire FEAs were prepared on glass substrates in our research, demonstrating the feasibility of realizing large area a-IGZO TFT-controlled ZnO nanowire FEAs.

Cardiac peroxisome proliferator-activated receptor-γ expression is modulated by oxidative stress in acutely infrasound-exposed cardiomyocytes.

PubMed

Pei, Zhaohui; Meng, Rongsen; Zhuang, Zhiqiang; Zhao, Yiqiao; Liu, Fangpeng; Zhu, Miao-Zhang; Li, Ruiman

2013-12-01

The aim of the present study was to examine the effects of acute infrasound exposure on oxidative damage and investigate the underlying mechanisms in rat cardiomyocytes. Neonatal rat cardiomyocytes were cultured and exposed to infrasound for several days. In the study, the expression of CAT, GPx, SOD1, and SOD2 and their activities in rat cardiomyocytes in infrasound exposure groups were significantly decreased compared to those in the various time controls, along with significantly higher levels of O2 (-) and H2O2. Decreased cardiac cell viability was not observed in various time controls. A significant reduction in cardiac cell viability was observed in the infrasound group compared to the control, while significantly increased cardiac cell viability was observed in the infrasound exposure and rosiglitazone pretreatment group. Compared to the control, rosiglitazone significantly upregulated CAT, GPx, SOD1, and SOD2 expression and their activities in rat cardiomyocytes exposed to infrasound, while the levels of O2 (-) or H2O2 were significantly decreased. A potential link between a significant downregulation of PPAR-γ expression in rat cardiomyocytes in the infrasound group was compared to the control and infrasound-induced oxidative stress. These findings indicate that infrasound can induce oxidative damage in rat cardiomyocytes by inactivating PPAR-γ.

Influence of Endodontic Treatment on Systemic Oxidative Stress

PubMed Central

Inchingolo, Francesco; Marrelli, Massimo; Annibali, Susanna; Cristalli, Maria Paola; Dipalma, Gianna; Inchingolo, Alessio Danilo; Palladino, Antonio; Inchingolo, Angelo Michele; Gargari, Marco; Tatullo, Marco

2014-01-01

Introduction: An increased production of oxidizing species related to reactive oral diseases, such as chronic apical periodontitis, could have systemic implications such as an increase in cardiovascular morbidity. Based on this consideration, we conducted a prospective study to assess whether subjects affected by chronic periodontitis presented with higher values of oxidative stress than reference values before endodontic treatment, and whether endodontic treatment can reduce the oxidative imbalance and bring it back to normal in these subjects. Materials and methods: The authors recruited 2 groups of patients from private studies and dental clinics: these patients were recruited randomly. The oxidative balance in both patients with chronic apical periodontitis (CAP) and healthy control patients was determined by measuring the oxidant status, using an identification of the reactive oxygen metabolites (d-ROMs) test, while the antioxidant status in these patients was determined using a biological antioxidant potential (BAP) test. Both these tests were carried on plasma samples taken from enrolled patients. Values were measured both before the endodontic treatment of the patients with chronic apical periodontitis, and 30 and 90 days after treatment, and compared to those obtained from healthy control patients. Results: It was found that, on recruitment, the patients with chronic apical periodontitis exhibited significantly higher levels of oxidative stress than control patients, as determined by the d-ROMs and BAP tests. Furthermore, the d-ROMs test values were shown to decrease and the BAP test values to increase over time in patients with chronic apical periodontitis following endodontic therapy. As the levels of oxidative stress in these patients tended to reduce and return to normal by 90 days following treatment. Conclusions: This study has demonstrated a positive association between chronic apical periodontitis and oxidative stress. Subjects affected by chronic apical periodontitis are exposed to a condition of oxidative stress, which is extremely dangerous to general health. Moreover, one can infer from these findings that through proper endodontic therapy, a good oxidative balance can be restored, thereby avoiding the risk of contracting the abovementioned diseases. PMID:24396280

Maternal plasma levels of interleukin-6, C-reactive protein, vitamins C, E and A, 8-isoprostane and oxidative status in women with preterm premature rupture of membranes.

PubMed

Ilhan, Nevin; Celik, Ebru; Kumbak, Banu

2015-02-01

Preterm premature rupture of membranes (PPROM) is associated with significant maternal and perinatal morbidity. This study examined maternal oxidative stress in PPROM. This was a prospective cross-sectional study conducted in a university hospital. A total of 72 pregnant women were recruited into two groups, those with PPROM (38 cases) and those without PPROM (34 controls) matched for gestational age. Plasma interleukin-6, C-reactive protein, vitamins C, E and A, 8-isoprostane, total oxidant status (TOS) and antioxidant status (TAS) were determined for all study participants and the data were compared between the PPROM and control groups. Both case and control groups were comparably matched in age, parity, gestational age and smoking status. There was a significant association between low 8-isoprostane, low vitamin C and high total oxidant status and the occurrence of PPROM (p < 0.001). Plasma vitamin C and 8-isoprostane levels were lower and TOS higher in women with PPROM. Further research is needed to identify robust biological markers for the prevention and also prognosis of PPROM.

Nitrous oxide/oxygen mixture for analgesia in adult cancer patients with breakthrough pain: A randomized, double-blind controlled trial.

PubMed

Liu, Q; Gao, L-L; Dai, Y-L; Li, Y-X; Wang, Y; Bai, C-F; Mu, G-X; Chai, X-M; Han, W-J; Zhou, L-J; Zhang, Y-J; Tang, L; Liu, J; Yu, J-Q

2018-03-01

The aim of this study was to assess the efficacy of a fixed nitrous oxide/oxygen mixture for the management of breakthrough cancer pain. A double-blind, placebo-controlled, randomized clinical trial was undertaken in the Medical ward of Tumor Hospital of General Hospital of Ningxia Medical University. 240 cancer patients with breakthrough pain were recruited and randomly received a standard pain treatment (morphine sulphate immediate release) plus a pre-prepared nitrous oxide/oxygen mixture, or the standard pain treatment plus oxygen. The primary endpoint measure was the numerical rating scale (NRS) score measured at baseline, 5 and 15 min after the beginning of treatment, and at 5 min post treatment. In all, analysis of pain score (NRS) at 5 min after the beginning of treatment shown a significant decrease in nitrous oxide/oxygen mixture treated patients with 2.8 ± 1.3 versus 5.5 ± 1.2 in controls (p < 0.01). At 15 min during the intervention, the mean pain score for nitrous oxide/oxygen was 2.0 ± 1.1 compared with 5.6 ± 1.3 for oxygen (p < 0.01). This study shows that self-administered nitrous oxide/oxygen mixture was effective in reducing moderate to severe breakthrough pain among patients with cancer. The management of breakthrough cancer pain is always a challenge due to its temporal characteristics of rapid onset, moderate to severe in intensity, short duration (median 30-60 min). Our study find that self-administered nitrous oxide/oxygen mixture was effective in reducing moderate to severe breakthrough cancer pain. © 2017 European Pain Federation - EFIC®.

Influence of controlled surface oxidation on the magnetic anisotropy of Co ultrathin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di, N.; Maroun, F., E-mail: fouad.maroun@polytechnique.fr; Allongue, P.

2015-03-23

We studied the influence of controlled surface-limited oxidation of electrodeposited epitaxial Co(0001)/Au(111) films on their magnetic anisotropy energy using real time in situ magneto optical Kerr effect and density functional theory (DFT) calculations. We investigated the Co first electrochemical oxidation step which we demonstrate to be completely reversible and determined the structure of this oxide layer. We show that the interface magnetic anisotropy of the Co film increases by 0.36 erg/cm{sup 2} upon Co surface oxidation. We performed DFT calculations to determine the different surface structures in a wide potential range as well as the charge transfer at the Co surface.more » Our results suggest that the magnetic anisotropy change is correlated with a positive charge increase of 0.54 e{sup −} for the Co surface atom upon oxidation.« less

Thermodynamic Versus Surface Area Control of Microbial Fe(III) Oxide Reduction Kinetics

NASA Astrophysics Data System (ADS)

Roden, E. E.

2003-12-01

Recent experimental studies of synthetic and natural Fe(III) oxide reduction permit development of conceptual and quantitative models of enzymatic Fe(III) oxide reduction at circumneutral pH that can be compared to and contrasted with established models of abiotic mineral dissolution. The findings collectively support a model for controls on enzymatic reduction that differs fundamentally from those applied to abiotic reductive dissolution as a result of two basic phenomena: (1) the relatively minor influence of oxide mineralogical and thermodynamic properties on surface area-normalized rates of enzymatic reduction compared to abiotic reductive dissolution; and (2) the major limitation which sorption and/or surface precipitation of biogenic Fe(II) on residual oxide and Fe(III)-reducing bacterial cell surfaces poses to enzymatic electron transfer in the presence of excess electron donor. Parallel studies with two major Fe(III)-reducing bacteria genera (Shewanella and Geobacter) lead to common conclusions regarding the importance of these phenomena in regulating the rate and long-term extent of Fe(III) oxide reduction. Although the extent to which these phenomena can be traced to underlying kinetic vs. thermodynamic effects cannot be resolved with current information, models in which rates of enzymatic reduction are limited kinetically by the abundance of "available" oxide surface sites (as controlled by oxide surface area and the abundance of surface-bound Fe(II)) provide an adequate macroscopic description of controls on the initial rate and long-term extent of oxide reduction. In some instances, thermodynamic limitation posed by the accumulation of aqueous reaction end-products (i.e. Fe(II) and alkalinity) must also be invoked to explain observed long-term patterns of reduction. In addition, the abundance of Fe(III)-reducing microorganisms plays an important role in governing rates of reduction and needs to be considered in models of Fe(III) reduction in nonsteady-state systems, e.g. subsurface environments in which Fe(III) reduction is stimulated by contamination with organics or for the purposes of metal/radionuclide bioremediation.

Control of Sulfidogenesis Through Bio-oxidation of H 2S Coupled to (per)chlorate Reduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gregoire, Patrick; Engelbrektson, Anna; Hubbard, Christopher G.

2014-04-04

Here, we investigate H 2S attenuation by dissimilatory perchlorate-reducing bacteria (DPRB). All DPRB tested oxidized H 2S coupled to (per)chlorate reduction without sustaining growth. H 2S was preferentially utilized over organic electron donors resulting in an enriched (34S)-elemental sulfur product. Electron microscopy revealed elemental sulfur production in the cytoplasm and on the cell surface of the DPRB Azospira suillum. We also propose a novel hybrid enzymatic-abiotic mechanism for H 2S oxidation similar to that recently proposed for nitrate-dependent Fe(II) oxidation. The results of this study have implications for the control of biosouring and biocorrosion in a range of industrial environments.

Comparison of serum oxidant and antioxidant parameters in familial Mediterranean fever patients (FMF) with attack free period.

PubMed

Şahin, Ali; Erten, Şükran; Altunoğlu, Alpaslan; Işıkoğlu, Semra; Neşelioğlu, Salim; Ergin, Merve; Atalay, Hacı Veli; Erel, Özcan

2014-01-01

Familial Mediterranean fever (FMF) is an autoinflammatory, autosomal recessive, inherited disease characterized by recurrent self-limiting attacks of serosal surfaces. The imbalance of oxidants/antioxidants may play a role in such attacks. In this study, we aimed to evaluate the relationship between serum paraoxonase (PON1) activity, PON1 phenotype, and other parameters in patients with FMF and healthy controls. A total of 120 FMF patients with an attack-free period (AFP) and 65 healthy subjects were included in this study. The serum PON1 activity, stimulated paraoxonase (SPON) activity, PON1 phenotype (representing Q192R polymorphism; QQ, QR, RR), arylesterase activity, total oxidant status (TOS), total antioxidant capacity (TAC), oxidative stress index (OSI), advanced oxidative protein products (AOPP), total thiols (TTL), and ischemia-modified albumin (IMA) and cystatin-c (CYS-C) levels were measured. For the QQ phenotype, the median TTL and AOPP levels of the control group were 264.50 (57.75) mol/L and 21.26 (21.17) mmol/L, respectively, whereas the median TTL, AOPP levels of the patients were 309.00 (47.00) mol/L and 12.98 (6.96) mmol/L, respectively. There was a statistically significant difference between the patients and controls with the QQ phenotype in terms of TTL and AOPP (p< 0.001 and p= 0.004, respectively). However, there were no statistically significant differences between the QQ and QR+RR phenotypes with respect to TAC, TOS, OSI, or the other parameters. The FMF patients with AFP had higher TTL and lower AOPP levels than the controls. However, other oxidant and antioxidant parameters were similar among the patients during AFP and the controls.

Increased plasma peroxides as a marker of oxidative stress in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

PubMed

Maes, Michael; Kubera, Marta; Uytterhoeven, Marc; Vrydags, Nicolas; Bosmans, Eugene

2011-04-01

There is evidence that myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by activation of immune, inflammatory, oxidative and nitrosative stress (IO&NS) pathways. The present study was carried out in order to examine whether ME/CFS is accompanied by increased levels of plasma peroxides and serum oxidized LDL (oxLDL) antibodies, two biomarkers of oxidative stress. Blood was collected from 56 patients with ME/CFS and 37 normal volunteers. Severity of ME/CFS was measured using the Fibromyalgia and Chronic Fatigue Syndrome (FF) Rating Scale. Plasma peroxide concentrations were significantly higher in patients with ME/CFS than in normal controls. There was a trend towards significantly higher serum oxLDL antibodies in ME/CFS than in controls. Both biomarkers contributed significantly in discriminating between patients with ME/CFS and normal controls. Plasma peroxide and serum oxLDL antibody levels were both significantly related to one of the FF symptoms. The results show that ME/CFS is characterized by increased oxidative stress.

Thymoquinone protects end organs from abdominal aorta ischemia/reperfusion injury in a rat model.

PubMed

Aydin, Mehmet Salih; Kocarslan, Aydemir; Kocarslan, Sezen; Kucuk, Ahmet; Eser, İrfan; Sezen, Hatice; Buyukfirat, Evren; Hazar, Abdussemet

2015-01-01

Previous studies have demonstrated that thymoquinone has protective effects against ischemia reperfusion injury to various organs like lungs, kidneys and liver in different experimental models. We aimed to determine whether thymoquinone has favorable effects on lung, renal, heart tissues and oxidative stress in abdominal aorta ischemia-reperfusion injury. Thirty rats were divided into three groups as sham (n=10), control (n=10) and thymoquinone (TQ) treatment group (n=10). Control and TQ-treatment groups underwent abdominal aorta ischemia for 45 minutes followed by a 120-min period of reperfusion. In the TQ-treatment group, thymoquinone was given 5 minutes. before reperfusion at a dose of 20 mg/kg via an intraperitoneal route. Total antioxidant capacity, total oxidative status (TOS), and oxidative stress index (OSI) in blood serum were measured and lung, kidney, and heart tissue histopathology were evaluated with light microscopy. Total oxidative status and oxidative stress index activity in blood samples were statistically higher in the control group compared to the sham and TQ-treatment groups (P<0.001 for TOS and OSI). Control group injury scores were statistically higher compared to sham and TQ-treatment groups (P<0.001 for all comparisons). Thymoquinone administered intraperitoneally was effective in reducing oxidative stress and histopathologic injury in an acute abdominal aorta ischemia-reperfusion rat model.

The effect of short-term, high-dose oral N-acetylcysteine treatment on oxidative stress markers in cystic fibrosis patients with chronic P. aeruginosa infection -- a pilot study.

PubMed

Skov, Marianne; Pressler, Tacjana; Lykkesfeldt, Jens; Poulsen, Henrik Enghusen; Jensen, Peter Østrup; Johansen, Helle Krogh; Qvist, Tavs; Kræmer, Dorthe; Høiby, Niels; Ciofu, Oana

2015-03-01

Patients with cystic fibrosis (CF) and chronic Pseudomonas aeruginosa lung infection have increased oxidative stress as a result of an imbalance between the production of reactive oxygen species caused by inflammation and their inactivation by the impaired antioxidant systems. Supplementation with anti-oxidants is potentially beneficial for CF patients. The effect of 4 weeks of oral N-acetylcysteine (NAC) treatment (2400 mg/day divided into two doses) on biochemical parameters of oxidative stress was investigated in an open-label, controlled, randomized trial on 21 patients; 11 patients in the NAC group and 10 in the control group. Biochemical parameters of oxidative burden and plasma levels of antioxidants were assessed at the end of the study and compared to the baseline values in the two groups. A significant increase in the plasma levels of the antioxidant ascorbic acid (p=0.037) and a significant decrease in the levels of the oxidized form of ascorbic acid (dehydroascorbate) (p=0.004) compared to baseline were achieved after NAC treatment. No significant differences were observed in the control group. The parameters of oxidative burden did not change significantly compared to baseline in either of the groups. A better lung function was observed in the NAC treated group with a mean (SD) change compared to baseline of FEV1% predicted of 2.11 (4.6), while a decrease was observed in the control group (change -1.4 (4.6)), though not statistically significant. Treatment with N-acetylcysteine 1200 mg×2/day for 30 days significantly decreased the level of oxidized vitamin C and increased the level of vitamin C (primary end-points) and a not statistically significant improvement of lung function was observed in this group of patients. Copyright © 2014 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Patients with chronic fatigue syndrome performed worse than controls in a controlled repeated exercise study despite a normal oxidative phosphorylation capacity.

PubMed

Vermeulen, Ruud C W; Kurk, Ruud M; Visser, Frans C; Sluiter, Wim; Scholte, Hans R

2010-10-11

The aim of this study was to investigate the possibility that a decreased mitochondrial ATP synthesis causes muscular and mental fatigue and plays a role in the pathophysiology of the chronic fatigue syndrome (CFS/ME). Female patients (n = 15) and controls (n = 15) performed a cardiopulmonary exercise test (CPET) by cycling at a continuously increased work rate till maximal exertion. The CPET was repeated 24 h later. Before the tests, blood was taken for the isolation of peripheral blood mononuclear cells (PBMC), which were processed in a special way to preserve their oxidative phosphorylation, which was tested later in the presence of ADP and phosphate in permeabilized cells with glutamate, malate and malonate plus or minus the complex I inhibitor rotenone, and succinate with rotenone plus or minus the complex II inhibitor malonate in order to measure the ATP production via Complex I and II, respectively. Plasma CK was determined as a surrogate measure of a decreased oxidative phosphorylation in muscle, since the previous finding that in a group of patients with external ophthalmoplegia the oxygen consumption by isolated muscle mitochondria correlated negatively with plasma creatine kinase, 24 h after exercise. At both exercise tests the patients reached the anaerobic threshold and the maximal exercise at a much lower oxygen consumption than the controls and this worsened in the second test. This implies an increase of lactate, the product of anaerobic glycolysis, and a decrease of the mitochondrial ATP production in the patients. In the past this was also found in patients with defects in the mitochondrial oxidative phosphorylation. However the oxidative phosphorylation in PBMC was similar in CFS/ME patients and controls. The plasma creatine kinase levels before and 24 h after exercise were low in patients and controls, suggesting normality of the muscular mitochondrial oxidative phosphorylation. The decrease in mitochondrial ATP synthesis in the CFS/ME patients is not caused by a defect in the enzyme complexes catalyzing oxidative phosphorylation, but in another factor. NL16031.040.07.

Oxidative damage of DNA in subjects occupationally exposed to lead.

PubMed

Pawlas, Natalia; Olewińska, Elżbieta; Markiewicz-Górka, Iwona; Kozłowska, Agnieszka; Januszewska, Lidia; Lundh, Thomas; Januszewska, Ewa; Pawlas, Krystyna

2017-09-01

Exposure to lead (Pb) in environmental and occupational settings continues to be a serious public health problem and may pose an elevated risk of genetic damage. The aim of this study was to assess the level of oxidative stress and DNA damage in subjects occupationally exposed to lead. We studied a population of 78 male workers exposed to lead in a lead and zinc smelter and battery recycling plant and 38 men from a control group. Blood lead levels were detected by graphite furnace atomic absorption spectrophotometry and plasma lead levels by inductively coupled plasma-mass spectrometry. The following assays were performed to assess the DNA damage and oxidative stress: comet assay, determination of 8-hydroxy-2'-deoxyguanosine (8-OHdG), lipid peroxidation and total antioxidant status (TAS). The mean concentration of lead in the blood of the exposed group was 392 ± 103 μg/L and was significantly higher than in the control group (30.3 ± 29.4 μg/L, p < 0.0001). Oxidative DNA damages measured by comet assay showed no significant differences between populations. The concentration of 8-OHdG was about twice as high as in the control group. We found a significant positive correlation between the level of biomarkers of lead exposure [lead in blood, lead in plasma, zinc protoporphyrin (ZPP)] and urine concentration of 8-OHdG. The level of oxidative damage of DNA was positively correlated with the level of lipid peroxidation (TBARS) and negatively with total anti-oxidative status (TAS). Our study suggests that occupational exposure causes an increase in oxidative damage to DNA, even in subjects with relatively short length of service (average length of about 10 years). 8-OHdG concentration in the urine proved to be a sensitive and non-invasive marker of lead induced genotoxic damage.

Association of Oxidative Stress Biomarkers with Gestational Diabetes Mellitus in Pregnant Women: A Case-Control Study

PubMed Central

Zhu, Chunyan; Yang, Hongling; Geng, Qingshan; Ma, Qingling; Long, Yan; Zhou, Cheng; Chen, Ming

2015-01-01

Objective The relationship between gestational diabetes mellitus (GDM) and oxidative stress has not been fully elucidated. This study examined the association between biomarkers of oxidative stress and GDM. Methods We conducted a case-control study which included 36 women presenting with GDM and 36 asymptomatic matched control subjects who visited Guangzhou Women and Children’s Medical Centre, China, from June 2012 to December 2012. Pregnant women were prospectively recruited to the study, and blood samples were collected at the time of a routine oral glucose tolerance test. These samples were then analyzed for levels of endocrine and surrogate markers of oxidative stress. Results Compared to control subjects, women with GDM exhibited elevated values for plasma glucose, insulin, and insulin resistance (IR), and showed reduced HOMA pancreatic β-cell function (HOMA-B), insulin sensitivity index (ISI), insulinogenic index, and corrected insulin response at 24–28 weeks gestation. A bivariate logistic regression analysis showed that levels of high-sensitivity C reactive protein (hs-CRP) and high fluorescence reticulocytes at fasting, and hs-CRP in a 1-h OGTT, were significantly associated with GDM. A linear regression analysis showed that levels of hs-CRP (P = 0.003) and reticulocytes (P = 0.029) at fasting were associated with IR, and levels of hs-CRP (P = 0.002) and monocytes (P = 0.006) in a 1-h OGTT were associated with ISI. Conclusions Pregnant women with GDM developed a pathological IR and exhibited β-cell dysfunction. Their decreased ability to compensate for oxidative stress was associated with increased IR and a reduced ISI, which might be important factors in GDM. PMID:25915047

Controlled pilot oxidizer for a gas turbine combustor

DOEpatents

Laster, Walter R.; Bandaru, Ramarao V.

2010-07-13

A combustor (22) for a gas turbine (10) includes a main burner oxidizer flow path (34) delivering a first portion (32) of an oxidizer flow (e.g., 16) to a main burner (28) of the combustor and a pilot oxidizer flow path (38) delivering a second portion (36) of the oxidizer flow to a pilot (30) of the combustor. The combustor also includes a flow controller (42) disposed in the pilot oxidizer flow path for controlling an amount of the second portion delivered to the pilot.

Effects of bench step exercise intervention on work ability in terms of cardiovascular risk factors and oxidative stress: a randomized controlled study.

PubMed

Ohta, Masanori; Eguchi, Yasumasa; Inoue, Tomohiro; Honda, Toru; Morita, Yusaku; Konno, Yoshimasa; Yamato, Hiroshi; Kumashiro, Masaharu

2015-01-01

Work ability is partly determined by physical and mental fitness. Bench step exercise can be practiced anywhere at any time. The aim of this study was to determine the effects of a bench step exercise on work ability by examining cardiovascular risk factors and oxidative stress. Thirteen volunteers working in a warehousing industry comprised the bench step exercise group (n=7) and the control group (n=6). The participants in the step exercise group were encouraged to practice the step exercise at home for 16 weeks. The step exercise improved glucose metabolism and antioxidative capacity and increased work ability by reducing absences from work and improving the prognosis of work ability. The improvement in work ability was related to a reduction in oxidative stress. These results suggest that a bench step exercise may improve work ability by reducing cardiovascular risk factors and oxidative stress.

No association between alcohol supplementation and autoantibodies to DNA damage in postmenopausal women in a controlled feeding study.

PubMed

Mahabir, S; Baer, D J; Johnson, L L; Frenkel, K; Dorgan, J F; Cambell, W; Hartman, T J; Clevidence, B; Albanes, D; Judd, J T; Taylor, P R

2005-08-01

Alcohol consumption is linked to increased breast cancer risk. Since oestrogens increase breast cancer risk, possibly through oxidative damage, and we have shown that alcohol consumption increases serum oestrogens, we tested whether moderate alcohol supplementation increased oxidative DNA damage among healthy postmenopausal women not on hormone replacement therapy in a randomized controlled crossover study. We used serum 5-hydroxymethyl-2-deoxyuridine (5-HMdU) autoantibodies (aAbs) as a marker of oxidative DNA damage. The results showed no evidence for increased or decreased levels of oxidative DNA damage among women who consumed 15 g or 30 g alcohol per day for 8 weeks compared with women in the 0 g alcohol group. We conclude that among healthy women, it is possible that an 8-week trial of moderate alcohol supplementation might be too short to make enough 5-HMdU aAbs to compare differences by alcohol dose. In future studies, a panel of biomarkers for DNA damage should be used.

Serum GGT activity and hsCRP level in patients with type 2 diabetes mellitus with good and poor glycemic control: An evidence linking oxidative stress, inflammation and glycemic control.

PubMed

Gohel, Mukesh G; Chacko, Anusha N

2013-12-20

Diabetes is undoubtedly one of the most challenging health problems in 21st century. Understanding the pathogenesis and preventing long term complications have been major goals of research in diabetes mellitus (DM). Research in the past few years has linked oxidative stress and inflammation to beta cell dysfunction. Aim of this study is to evaluate serum gamma-glutamyl transferase (GGT) activity (marker of oxidative stress) and high sensitivity C reactive protein (hsCRP) level (an inflammatory marker) in type 2 DM subjects with good and poor glycemic control. Further, we investigated correlation between serum GGT and hsCRP level with glycemic control (FBS, PP2BS, HbA1c) in subjects. A cross sectional study consists of 150 patients out of them 50 patients having type 2 DM with good control (Group II), 50 patients with type 2 DM with poor control (Group III) and 50 normal healthy control (Group I) were selected. Serum GGT, serum hsCRP, FBS, PP2BS, HbA1c, and other biochemical investigations include serum liver enzymes and lipids were measured. Mean serum GGT and hsCRP concentration were statistically significantly higher in group III patients compared to group I and group II subjects as well as increased in group II compared to group I (p < 0.001). Further significant positive correlation was observed between GGT and hsCRP concentration as well as both with HbA1c, FBS, and PP2BS. Oxidative stress and inflammation appears to be a key component and also associated with poor glycemic control and further pathogenesis of diabetes and its complications. All our finding suggesting a link between oxidative stress, inflammation and glycemic control in patient with type 2 diabetes mellitus.

Impact of depressive symptoms on oxidative stress in patients with psoriasis.

PubMed

Karababa, Fatih; Yesilova, Yavuz; Turan, Enver; Selek, Salih; Altun, Hacer; Selek, Sahabettin

2013-01-01

Depression and anxiety disorders often accompany psoriasis. Increased reactive oxygen radicals and impaired antioxidant systems are considered to play a role both in psoriasis and depression and anxiety disorders. Accordingly, in this study, we aimed to investigate the effects of depressive and anxiety symptoms on oxidative stress in patients with psoriasis. Hospital Anxiety and Depression Scale (HADS) forms were completed by 39 psoriasis patients and 25 volunteer controls. Serum total antioxidant capacity (TAC) and total oxidant capacity (TOC) parameters were analysed in serum samples, after which oxidative stress index (OSI) was calculated in whole study population. Laboratory data were analysed with a Kruskal-Wallis test to determine the severity of HADS and the presence of psoriasis among four groups. The psoriasis patients had higher HADS scores, higher OSI and TOC levels, and lower TAC levels compared with the control group. Comparison among four groups with/without psoriasis and higher/lower HADS scores revealed statistically significant differences with regard to TAC (Kruskal-Wallis P = 0.0047) and TOC (Kruskal-Wallis P < 0.001) levels and OSI (Kruskal-Wallis P < 0.001); the difference was mainly based on the difference between cases with and without psoriasis and on HADS scores in control subjects (P < 0.05 for post hoc comparisons). TAC, TOC, and OSI levels did not differ significantly in psoriasis patients with regard to higher or lower HADS scores. Based on the findings of this study, the presence of either psoriasis or higher HADS scores in the control subjects was associated with increased oxidative stress, whereas presence of higher HADS scores did not lead to further increase in oxidative stress in psoriatic patients.

Comparisons of the oxidative stress biomarkers levels in gestational diabetes mellitus (GDM) and non-GDM among Thai population: cohort study.

PubMed

Rueangdetnarong, Hathairat; Sekararithi, Rattanaporn; Jaiwongkam, Thidarat; Kumfu, Sirinart; Chattipakorn, Nipon; Tongsong, Theera; Jatavan, Phudit

2018-05-01

The primary objective of this study was to compare the levels of oxidative stress biomarkers between pregnancies with gestational diabetes mellitus (GDM) and normoglycemic pregnancies. A prospective study was conducted on pregnant women at average risk for GDM. The participants were screened for GDM with glucose challenge test and confirmed by 100 g, 3-h oral glucose tolerance test and categorized into the control (non-GDM) and GDM groups. Maternal blood was collected from all participants at gestational age (GA) 24-28 weeks and early labor and fetal cord blood was collected for measurements of 8 Isoprostane (8Isop) (oxidative stress marker), TNF-α (inflammatory marker) and IL-10 (anti-inflammatory marker) and were followed up for maternal and neonatal outcomes. A total of 62 women, 30 in GDM and 32 in control group, met the inclusion criteria. At 24-28 weeks of gestation, maternal serum 8Isop and TNF-α levels were significantly higher in GDM group ( P  = 0.032 and P  = 0.047), in spite of good glycemic control. At early labor, maternal 8Isop levels were significantly higher in GDM ( P  = 0.001). The biomarkers in the cord blood as well as maternal and neonatal outcomes in both groups were not significantly different. GDM is significantly associated with inflammatory process when compared to normal pregnancy, as indicated by higher oxidative stress and apoptosis markers. However, such levels were not correlated with the pregnancy outcomes. An increase in oxidative stress could not be prevented by good glycemic control. Cord blood biomarker levels in pregnancy with GDM were not changed, suggesting that the placenta could be the barrier for the oxidative stress and cytokines. © 2018 The authors.

Decrease of oxidative phosphorylation system function in severe septic patients.

PubMed

Lorente, Leonardo; Martín, María M; López-Gallardo, Ester; Blanquer, José; Solé-Violán, Jordi; Labarta, Lorenzo; Díaz, César; Jiménez, Alejandro; Montoya, Julio; Ruiz-Pesini, Eduardo

2015-10-01

The comparison of oxidative phosphorylation system capacities between septic patients and control subjects has been scarcely analyzed and only in studies with small sample size (fewer than 40 septic patients and 40 controls). Thus, the objective of this study was to compare platelet respiratory complex IV (CIV) activity between severe septic patients and healthy individuals in a larger series (including 198 severe septic patients and 96 healthy controls). A prospective, multicenter, observational study was carried out in 6 Spanish intensive care units. We obtained blood samples from 198 severe septic patients at day 1, 4, and 8 of the severe sepsis diagnosis and 96 sex- and age-matched healthy control individuals and determined platelet CIV-specific activity. The end point of the study was 30-day mortality. Control individuals showed higher platelet CIV-specific activity (P < .001) than surviving (n = 130) or nonsurviving (n = 68) severe septic patients at day 1, 4, and 8 of severe sepsis diagnosis. The major finding of our work, involving the largest series to date of severe septic patients with data on oxidative phosphorylation system capacity, was that surviving and nonsurviving septic patients showed lower platelet CIV-specific activity during the first week of sepsis than healthy controls. Copyright © 2015 Elsevier Inc. All rights reserved.

Flux control exerted by mitochondrial outer membrane carnitine palmitoyltransferase over beta-oxidation, ketogenesis and tricarboxylic acid cycle activity in hepatocytes isolated from rats in different metabolic states.

PubMed Central

Drynan, L; Quant, P A; Zammit, V A

1996-01-01

The Flux Control Coefficients of mitochondrial outer membrane carnitine palmitoyltransferase (CPT I) with respect to the overall rates of beta-oxidation, ketogenesis and tricarboxylic acid cycle activity were measured in hepatocytes isolated from rats in different metabolic states (fed, 24 h-starved, starved-refed and starved/insulin-treated). These conditions were chosen because there is controversy as to whether, when significant control ceases to be exerted by CPT I over the rate of fatty oxidation [Moir and Zammit (1994) Trends Biochem. Sci. 19, 313-317], this is transferred to one or more steps proximal to acylcarnitine synthesis (e.g. decreased delivery of fatty acids to the liver) or to the reaction catalysed by mitochondrial 3-hydroxy-3-methyl-glutaryl-CoA synthase [Hegardt (1995) Biochem. Soc. Trans. 23, 486-490]. Therefore isolated hepatocytes were used in the present study to exclude the involvement of changes in the rate of delivery of non-esterified fatty acids (NEFA) to the liver, such as occur in vivo, and to ascertain whether, under conditions of constant supply of NEFA, CPT I retains control over the relevant fluxes of fatty acid oxidation to ketones and carbon dioxide, or whether control is transferred to another (intrahepatocytic) site. The results clearly show that the Flux Control Coefficients of CPT I with respect to overall beta-oxidation and ketogenesis are very high under all conditions investigated, indicating that control is not lost to another intrahepatic site during the metabolic transitions studied. The control of CPT I over tricarboxylic acid cycle activity was always very low. The significance of these findings for the integration of fatty acid and carbohydrate metabolism in the liver is discussed. PMID:8760364

Homocysteine levels after nitrous oxide anesthesia for living-related donor renal transplantation: a randomized, controlled, double-blind study.

PubMed

Coskunfirat, N; Hadimioglu, N; Ertug, Z; Akbas, H; Davran, F; Ozdemir, B; Aktas Samur, A; Arici, G

2015-03-01

Nitrous oxide anesthesia increases postoperative homocysteine concentrations. Renal transplantation candidates present with higher homocysteine levels than patients with no renal disease. We designed this study to investigate if homocysteine levels are higher in subjects receiving nitrous oxide for renal transplantation compared with subjects undergoing nitrous oxide free anesthesia. Data from 59 patients scheduled for living-related donor renal transplantation surgery were analyzed in this randomized, controlled, blinded, parallel-group, longitudinal trial. Patients were assigned to receive general anesthesia with (flowmeter was set at 2 L/min nitrous oxide and 1 L/min oxygen) or without nitrous oxide (2 L/min air and 1 L/min oxygen). We evaluated levels of total homocysteine and known determinants, including creatinine, folate, vitamin B12, albumin, and lipids. We evaluated factor V and von Willebrand factor (vWF) to determine endothelial dysfunction and creatinine kinase myocardial band (CKMB)-mass, troponin T to show myocardial ischemia preoperatively in the holding area (T1), after discontinuation of anesthetic gases (T2), and 24 hours after induction (T3). Compared with baseline, homocysteine concentrations significantly decreased both in the nitrous oxide (22.3 ± 16.3 vs 11.8 ± 9.9; P < .00001) and nitrous oxide-free groups (21.5 ± 15.3 vs 8.0 ± 5.7; P < .0001) at postoperative hour 24. The nitrous oxide group had significantly higher mean plasma homocysteine concentrations than the nitrous oxide-free group (P = .021). The actual homocysteine difference between groups was 3.8 μmol/L. This study shows that homocysteine levels markedly decrease within 24 hours after living-related donor kidney transplantation. Patients receiving nitrous oxide have a lesser reduction, but this finding is unlikely to have a clinical relevance. Copyright © 2015 Elsevier Inc. All rights reserved.

Control of size and viscoelastic properties of nanofibrillated cellulose from palm tree by varying the TEMPO-mediated oxidation time.

PubMed

Benhamou, Karima; Dufresne, Alain; Magnin, Albert; Mortha, Gérard; Kaddami, Hamid

2014-01-01

The main objective of the present study was to control and optimize the preparation of nanofibrillated cellulose (NFC) from the date palm tree by monitoring the oxidation time (degree of oxidation) of the pristine cellulose and the number of cycles through the homogenizer. The oxidation was monitored by TEMPO (1-oxo-2,2,6,6-tétraméthylpipyridine 1-oxyle) mediated oxidation. Evidence of the successful isolation of NFC was given by FE-SEM observation revealing fibrils with a width in the range 20-30nm, depending of the oxidation time. The evolution of the transparency of the aqueous NFC suspension and carboxylic content according to the degree of oxidation and number of cycles were also analyzed by UV-vis transmittance, Fourier-transform infrared spectroscopy (FT-IR), conductimetry, and X-ray diffraction analysis. A significant NFC length reduction occurred during the TEMPO-mediated oxidation. The rheological properties of NFC suspensions were characterized as function of the oxidation time. Dynamic rheology showed that the aqueous suspension behavior changed from liquid to gel depending on the concentration. The highest concentration studied was 1wt% and the modulus reached 1MPa which was higher than for non-oxidized NFC. An explanation of the gel structure evolution with the oxidation time applied to the NFC (NFC length) was proposed. The gel structure evolves from an entanglement-governed gel structure to an immobilized water molecule-governed one. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biomarkers of early genotoxicity and oxidative stress for occupational risk assessment of exposure to styrene in the fibreglass reinforced plastic industry.

PubMed

Cavallo, Delia; Tranfo, Giovanna; Ursini, Cinzia Lucia; Fresegna, Anna Maria; Ciervo, Aureliano; Maiello, Raffaele; Paci, Enrico; Pigini, Daniela; Gherardi, Monica; Gatto, Maria Pia; Buresti, Giuliana; Iavicoli, Sergio

2018-06-10

This study aimed to identify sensitive and not-invasive biomarkers of early genotoxic/oxidative effect for exposure to styrene in the fibreglass reinforced plastic manufacture. We studied 11 workers of a plastic manufacture using open molding process (A), 16 workers of a manufacture using closed process (B) and 12 controls. We evaluated geno/cytotoxic effects on buccal cells by Buccal Micronucleus Cytome (BMCyt) assay and genotoxic/oxidative effects on lymphocytes by Fpg-comet test. On A workers we also evaluated urinary 8oxoGua, 8oxodGuo and 8oxoGuo to investigate oxidative stress. Personal inhalation exposure to styrene was monitored by passive air sampling and GC/MS. Biological monitoring included urinary metabolites mandelic acid (MA) and phenylglyoxylic acid (PGA). The findings show higher styrene exposure, urinary MA + PGA levels and micronucleus frequency in manufacture A. Higher buccal karyolytic cell frequency vs controls were found in both exposed populations. We found in exposed workers, no induction of direct DNA damage but oxidative DNA damage. Fpg-comet assay and urinary oxidized guanine seem to be sensitive biomarkers of oxidative stress and BMCyt assay a good-not invasive biomarker of cyto-genotoxicity at target organ. The study, although limited by the small number of studied subjects, shows the usefulness of used biomarkers in risk assessment of styrene-exposed workers. Copyright © 2018 Elsevier B.V. All rights reserved.

Resting energy expenditure and carbohydrate oxidation are higher in elderly patients with COPD: a case control study

PubMed Central

2012-01-01

Background Elderly patients with chronic obstructive pulmonary disease (COPD) usually have a compromised nutritional status which is an independent predictor of morbidity and mortality. To know the Resting Energy Expenditure (REE) and the substrate oxidation measurement is essential to prevent these complications. This study aimed to compare the REE, respiratory quotient (RQ) and body composition between patients with and without COPD. Methods This case–control study assessed 20 patients with chronic obstructive pulmonary disease attending a pulmonary rehabilitation program. The group of subjects without COPD (control group) consisted of 20 elderly patients attending a university gym, patients of a private service and a public healthy care. Consumption of oxygen (O2) and carbon dioxide (CO2) was determined by indirect calorimetry and used for calculating the resting energy expenditure and respiratory quotient. Body mass index (BMI) and waist circumference (WC) were also measured. Percentage of body fat (%BF), lean mass (kg) and muscle mass (kg) were determined by bioimpedance. The fat free mass index (FFMI) and muscle mass index (MMI) were then calculated. Results The COPD group had lower BMI than control (p = 0.02). However, WC, % BF, FFMI and MM-I did not differ between the groups. The COPD group had greater RQ (p = 0.01), REE (p = 0.009) and carbohydrate oxidation (p = 0.002). Conclusions Elderly patients with COPD had higher REE, RQ and carbohydrate oxidation than controls. PMID:22672689

Efficacy and safety of nitric oxide fumigation for controlling codling moth in apples

USDA-ARS?s Scientific Manuscript database

Nitric oxide (NO) fumigation under ultralow oxygen (ULO) conditions was studied for its efficacy in controlling codling moth and effects on postharvest quality of apples. NO fumigation was effective against eggs and larvae of different sizes on artificial diet in 48 h treatments. Small larvae were...

Simultaneous control of Hg0, SO2, and NOx by novel oxidized calcium-based sorbents.

PubMed

Ghorishi, S Behrooz; Singer, Carl F; Jozewicz, Wojciech S; Sedman, Charles B; Srivastava, Ravi K

2002-03-01

Efforts to develop multipollutant control strategies have demonstrated that adding certain oxidants to different classes of Ca-based sorbents leads to a significant improvement in elemental Hg vapor (Hg0), SO2, and NOx removal from simulated flue gases. In the study presented here, two classes of Ca-based sorbents (hydrated limes and silicate compounds) were investigated. A number of oxidizing additives at different concentrations were used in the Ca-based sorbent production process. The Hg0, SO2, and NOx capture capacities of these oxidant-enriched sorbents were evaluated and compared to those of a commercially available activated carbon in bench-scale, fixed-bed, and fluid-bed systems. Calcium-based sorbents prepared with two oxidants, designated C and M, exhibited Hg0 sorption capacities (approximately 100 microg/g) comparable to that of the activated carbon; they showed far superior SO2 and NOx sorption capacities. Preliminary cost estimates for the process utilizing these novel sorbents indicate potential for substantial lowering of control costs, as compared with other processes currently used or considered for control of Hg0, SO2, and NOx emissions from coal-fired boilers. The implications of these findings toward development of multipollutant control technologies and planned pilot and field evaluations of more promising multipollutant sorbents are summarily discussed.

Oxidative stress markers in saliva and periodontal disease status: modulation during pregnancy and postpartum.

PubMed

Gümüş, Pınar; Emingil, Gülnur; Öztürk, Veli-Özgen; Belibasakis, Georgios N; Bostanci, Nagihan

2015-07-08

Periodontal diseases may affect local and systemic inflammation, and reactive oxygen species (ROS) levels. This systemic health burden could compromise the outcome of pregnancy in expectant mothers. The aim of the present study was to evaluate oxidative stress markers, including glutathione peroxidase (GPx), thiobarbituric acid-reactive substances (TBARS) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), and total bacterial loads in the saliva of pregnant and postpartum women, and to investigate their association with periodontal disease severity. A total of 187 women were originally recruited for this case-control study, assigned to the following groups a) pregnant group, b) postpartum group: the pregnant group re-evaluated 6 months after giving birth, c) control group: systemically healthy and non-pregnant women. The levels of the studied oxidative stress markers in saliva were measured by commercially available kits. The levels of salivary 8-OHdG were significantly elevated in the pregnant, compared with the control group. Although salivary 8-OHdG levels slightly decreased after giving birth (postpartum group), the difference did not reach significance. In contrast, the activity of antioxidant enzyme GPx in saliva was significantly lower in the pregnant than the control group. Although no differences in lipid peroxidation (represented by TBARS) were observed between the pregnant and control groups, after giving birth TBARS levels were significantly lowered. Only in the postpartum and control groups did clinical measurements of periodontal disease severity correlate with oxidative stress markers. Interestingly, there were no such correlations with TBARS in the pregnant and postpartum groups. The present study shows changes in the oxidant/antioxidant balance in saliva during pregnancy and after birth, which may be affected by periodontal health status in the latter case. Whether this is associated with adverse pregnancy outcomes, or not, remains to be elucidated. Early identification of ROS markers in saliva may be of clinical value in the periodontal management of pregnant women.

Ligand-controlled Fe mobilization catalyzed by adsorbed Fe(II) on Fe(hydr)oxides

NASA Astrophysics Data System (ADS)

Kang, Kyounglim; Biswakarma, Jagannath; Borowski, Susan C.; Hug, Stephan J.; Hering, Janet G.; Schenkeveld, Walter D. C.; Kraemer, Stephan M.

2017-04-01

Dissolution of Fe(hydr)oxides is a key process in biological iron acquisition. Due to the low solubility of iron oxides in environments with a circumneutral pH, organisms may exude organic compounds catalyzing iron mobilization by reductive and ligand controlled dissolution mechanisms. Recently, we have shown synergistic effects between reductive dissolution and ligand-controlled dissolution that may operate in biological iron acquisition. The synergistic effects were observed in Fe mobilization from single goethite suspensions as well as in suspensions containing calcareous soil[1],[2]. However, how the redox reaction accelerates Fe(hydr)oxide dissolution by ligands is not studied intensively. In our study, we hypothesized that electron transfer to structural Fe(III) labilizes the Fe(hydr)oxide structure, and that this can accelerate ligand controlled dissolution. Systematical batch dissolution experiments were carried out under anoxic conditions at environmentally relevant pH values in which various Fe(hydr)oxides (goethite, hematite, lepidocrocite) interacted with two different types of ligand (desferrioxamine B (DFOB) and N,N'-Di(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid monohydrochloride (HBED)). Electron transfer to the structure was induced by adsorbing Fe(II) to the mineral surface at various Fe(II) concentrations. Our results show a distinct catalytic effect of adsorbed Fe(II) on ligand controlled dissolution, even at submicromolar Fe(II) concentrations. We observed the effect for a range of iron oxides, but it was strongest in lepidocrocite, most likely due to anisotropy in conductivity leading to higher near-surface concentration of reduced iron. Our results demonstrate that the catalytic effect of reductive processes on ligand controlled dissolution require a very low degree of reduction making this an efficient process for biological iron acquisition and a potentially important effect in natural iron cycling. References 1. Wang, Z. M.; Schenkeveld, W. D. C.; Kraemer, S. M.; Giammar, D. E. Environ. Sci. Technol. 2015, 49, (12), 7236-7244. 2. Schenkeveld, W. D. C.; Wang, Z. M.; Giammar, D. E.; Kraemer, S. M. Environ. Sci. Technol. 2016, 50, (12), 6381-6388.

Effect of Lycopene Supplementation on Oxidative Stress: An Exploratory Systematic Review and Meta-Analysis of Randomized Controlled Trials

PubMed Central

Chen, Jinyao; Song, Yang

2013-01-01

Abstract Lycopene is a potentially useful compound for preventing and treating cardiovascular diseases and cancers. Studies on the effects of lycopene on oxidative stress offer insights into its mechanism of action and provide evidence-based rationale for its supplementation. In this analysis, randomized controlled trials of the effects of oral lycopene supplementation on any valid outcomes of oxidative stress were identified and pooled through a search of international journal databases and reference lists of relevant publications. Two reviewers extracted data from each of the identified studies. Only studies of sufficient quality were included. Twelve parallel trials and one crossover trial were included in the systematic review, and six trials provided data for quantitative meta-analysis. Our results indicate that lycopene supplementation significantly decreases the DNA tail length, as determined using comet assays, with a mean difference (MD) of −6.27 [95% confidence interval (CI) −10.74, −1.90] (P=.006) between the lycopene intervention groups and the control groups. Lycopene supplementation does not significantly prolong the lag time of low-density lipoprotein (MD 3.76 [95% CI −2.48, 10.01]; P=.24). Lycopene possibly alleviates oxidative stress; however, biomarker research for oxidative stress needs be more consistent with the outcomes in lycopene intervention trials for disease prevention. PMID:23631493

Structure and Electronic Properties of Interface-Confined Oxide Nanostructures

DOE PAGES

Liu, Yun; Ning, Yanxiao; Yu, Liang; ...

2017-09-16

The controlled fabrication of nanostructures has often made use of a substrate template to mediate and control the growth kinetics. Electronic substrate-mediated interactions have been demonstrated to guide the assembly of organic molecules or the nucleation of metal atoms but usually at cryogenic temperatures, where the diffusion has been limited. Combining STM, STS, and DFT studies, we report that the strong electronic interaction between transition metals and oxides could indeed govern the growth of low-dimensional oxide nanostructures. As a demonstration, a series of FeO triangles, which are of the same structure and electronic properties but with different sizes (side lengthmore » >3 nm), are synthesized on Pt(111). The strong interfacial interaction confines the growth of FeO nanostructures, leading to a discrete size distribution and a uniform step structure. Given the same interfacial configuration, as-grown FeO nanostructures not only expose identical edge/surface structure but also exhibit the same electronic properties, as manifested by the local density of states and local work functions. We expect the interfacial confinement effect can be generally applied to control the growth of oxide nanostructures on transition metal surfaces. These oxide nanostructures of the same structure and electronic properties are excellent models for studies of nanoscale effects and applications.« less

Structure and Electronic Properties of Interface-Confined Oxide Nanostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yun; Ning, Yanxiao; Yu, Liang

The controlled fabrication of nanostructures has often made use of a substrate template to mediate and control the growth kinetics. Electronic substrate-mediated interactions have been demonstrated to guide the assembly of organic molecules or the nucleation of metal atoms but usually at cryogenic temperatures, where the diffusion has been limited. Combining STM, STS, and DFT studies, we report that the strong electronic interaction between transition metals and oxides could indeed govern the growth of low-dimensional oxide nanostructures. As a demonstration, a series of FeO triangles, which are of the same structure and electronic properties but with different sizes (side lengthmore » >3 nm), are synthesized on Pt(111). The strong interfacial interaction confines the growth of FeO nanostructures, leading to a discrete size distribution and a uniform step structure. Given the same interfacial configuration, as-grown FeO nanostructures not only expose identical edge/surface structure but also exhibit the same electronic properties, as manifested by the local density of states and local work functions. We expect the interfacial confinement effect can be generally applied to control the growth of oxide nanostructures on transition metal surfaces. These oxide nanostructures of the same structure and electronic properties are excellent models for studies of nanoscale effects and applications.« less

Copper Complex in Poly(vinyl chloride) as a Nitric Oxide-Generating Catalyst for the Control of Nitrifying Bacterial Biofilms.

PubMed

Wonoputri, Vita; Gunawan, Cindy; Liu, Sanly; Barraud, Nicolas; Yee, Lachlan H; Lim, May; Amal, Rose

2015-10-14

In this study, catalytic generation of nitric oxide by a copper(II) complex embedded within a poly(vinyl chloride) matrix in the presence of nitrite (source of nitric oxide) and ascorbic acid (reducing agent) was shown to effectively control the formation and dispersion of nitrifying bacteria biofilms. Amperometric measurements indicated increased and prolonged generation of nitric oxide with the addition of the copper complex when compared to that with nitrite and ascorbic acid alone. The effectiveness of the copper complex-nitrite-ascorbic acid system for biofilm control was quantified using protein analysis, which showed enhanced biofilm suppression when the copper complex was used in comparison to that with nitrite and ascorbic acid treatment alone. Confocal laser scanning microscopy (CLSM) and LIVE/DEAD staining revealed a reduction in cell surface coverage without a loss of viability with the copper complex and up to 5 mM of nitrite and ascorbic acid, suggesting that the nitric oxide generated from the system inhibits proliferation of the cells on surfaces. Induction of nitric oxide production by the copper complex system also triggered the dispersal of pre-established biofilms. However, the addition of a high concentration of nitrite and ascorbic acid to a pre-established biofilm induced bacterial membrane damage and strongly decreased the metabolic activity of planktonic and biofilm cells, as revealed by CLSM with LIVE/DEAD staining and intracellular adenosine triphosphate measurements, respectively. This study highlights the utility of the catalytic generation of nitric oxide for the long-term suppression and removal of nitrifying bacterial biofilms.

Clarithromycin, trimethoprim, and penicillin and oxidative nucleic acid modifications in humans: randomised, controlled trials.

PubMed

Larsen, Emil List; Cejvanovic, Vanja; Kjaer, Laura Kofoed; Pedersen, Morten Thorup; Popik, Sara Daugaard; Hansen, Lina Kallehave; Andersen, Jon Traerup; Jimenez-Solem, Espen; Broedbaek, Kasper; Petersen, Morten; Weimann, Allan; Henriksen, Trine; Lykkesfeldt, Jens; Torp-Pedersen, Christian; Poulsen, Henrik Enghusen

2017-08-01

In vitro studies have demonstrated that formation of reactive oxygen species (ROS) contributes to the effect of bactericidal antibiotics. The formation of ROS is not restricted to bacteria, but also occurs in mammalian cells. Oxidative stress is linked to several diseases. This study investigates whether antibiotic drugs induce oxidative stress in healthy humans as a possible mechanism for adverse reactions to the antibiotic drugs. This study contains information from two randomised, controlled trials. Participants underwent 1 week treatment with clarithromycin, trimethoprim, phenoxymethylpenicillin (penicillin V), or placebo. Oxidative modifications were measured as 24-h urinary excretion of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo), and plasma levels of malondialdehyde before and after treatment as a measurement of DNA oxidation, RNA oxidation, and lipid peroxidation, respectively. Clarithromycin significantly increased urinary excretion of 8-oxodG by 22.0% (95% confidence interval (CI): 3.6-40.4%) and 8-oxoGuo by 14.9% (95% CI: 3.7-26.1%). Further, we demonstrated that trimethoprim significantly lowered urinary excretion of 8-oxodG by 21.7% (95% CI: 5.8-37.6%), but did not influence urinary excretion of 8-oxoGuo. Penicillin V did not influence urinary excretion of 8-oxodG or 8-oxoGuo. None of the antibiotic drugs influenced plasma levels of malondialdehyde. Clarithromycin significantly increases oxidative nucleic acid modifications. Increased oxidative modifications might explain some of clarithromycin's known adverse reactions. Trimethoprim significantly lowers DNA oxidation but not RNA oxidation. Penicillin V had no effect on oxidative nucleic acid modifications. © 2017 The British Pharmacological Society.

Effect of short-term hazelnut consumption on DNA damage and oxidized LDL in children and adolescents with primary hyperlipidemia: a randomized controlled trial.

PubMed

Guaraldi, Federica; Deon, Valeria; Del Bo', Cristian; Vendrame, Stefano; Porrini, Marisa; Riso, Patrizia; Guardamagna, Ornella

2018-07-01

Children with primary hyperlipidemia are prone to develop premature atherosclerosis, possibly associated with increased oxidative stress. Nutritional therapy is the primary strategy in the treatment of hyperlipidemia and associated conditions. Dietary interventions with bioactive-rich foods, such as nuts, may contribute to the modulation of both lipid profile and the oxidative/antioxidant status. Our study aimed to assess the impact of a dietary intervention with hazelnuts on selected oxidative stress markers in children and adolescents with primary hyperlipidemia. A single-blind, 8-week, randomized, controlled, three-arm, parallel-group study was performed. Children and adolescents diagnosed with primary hyperlipidemia (n=60) received dietary guidelines and were randomized into three groups: group 1 received hazelnuts with skin (HZN+S), and group 2 hazelnuts without skin (HZN-S), at equivalent doses (15-30 g/day, based on body weight); group 3 (controls) received only dietary recommendations (no nuts). At baseline and after 8 weeks, plasma oxidized low-density lipoprotein (ox-LDL) concentrations, oxidative levels of DNA damage in PBMCs and potential correlation with changes in serum lipids were examined. A reduction of endogenous DNA damage by 18.9%±51.3% (P=.002) and 23.1%±47.9% (P=.007) was observed after HZN+S and HZN-S, respectively. Oxidatively induced DNA strand breaks decreased by 16.0%±38.2% (P=.02) following HZN+S treatment. Ox-LDL levels did not change after HZN+S intervention but positively correlated with total cholesterol and LDL cholesterol. A short-term hazelnut intervention improves cell DNA protection and resistance against oxidative stress but not ox-LDL in hyperlipidemic pediatric patients. The trial was registered at ISRCTN.com, ID no. ISRCTN12261900. Copyright © 2018 Elsevier Inc. All rights reserved.

Role of Paraoxonase 1 Activity and Oxidative/Antioxidative Stress Markers in Patients with Acute Cerebral Infarction.

PubMed

Zhu, Hui; Zhao, Teng; Liu, Jingyao

2018-06-01

Paraoxonase1 (PON1) is an antioxidant which confers antioxidant properties to high-density lipoprotein (HDL) and prevents low-density lipoprotein (LDL) oxidation. The purpose of this study was to evaluate the activities of PON1 and oxidative/antioxidative stress markers in acute cerebral infarction. In this study, 161 patients diagnosed with acute cerebral infarction and 161 gender- and age-matched healthy controls were recruited. Based on the clinicoradiological profiles, the patients were further classified into two groups: lacunar infarction group and large-artery atherosclerosis group. We measured the individual lipid status parameters, oxidative and antioxidative stress status parameters, and PON1 activity. Serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and oxidative stress parameters in patients with acute cerebral infarction were significantly higher than those in the normal controls (p < 0.05). High-density lipoprotein cholesterol (HDL-C) level, PON1 activity, superoxide dismutase (SOD) activity, and antioxidative stress parameters in patients were lower than in the normal controls (p < 0.05). Superoxide anion (O2-), malondialdehyde (MDA), and PON1 levels in the lacunar infarction group were lower than in the large-artery atherosclerosis group (p < 0.05). Oxidative stress markers and PON1 activity are sensitive indicators of acute cerebral infarction. Our findings suggest a severely impaired antioxidative protection mechanism in these patients. Our study provides new insights into the pathophysiological mechanisms of acute cerebral infarction, which may also provide new therapeutic targets for ischemic cerebrovascular diseases.

Endothelial and smooth muscle cells from abdominal aortic aneurysm have increased oxidative stress and telomere attrition.

PubMed

Cafueri, Giuseppe; Parodi, Federica; Pistorio, Angela; Bertolotto, Maria; Ventura, Francesco; Gambini, Claudio; Bianco, Paolo; Dallegri, Franco; Pistoia, Vito; Pezzolo, Annalisa; Palombo, Domenico

2012-01-01

Abdominal aortic aneurysm (AAA) is a complex multi-factorial disease with life-threatening complications. AAA is typically asymptomatic and its rupture is associated with high mortality rate. Both environmental and genetic risk factors are involved in AAA pathogenesis. Aim of this study was to investigate telomere length (TL) and oxidative DNA damage in paired blood lymphocytes, aortic endothelial cells (EC), vascular smooth muscle cells (VSMC), and epidermal cells from patients with AAA in comparison with matched controls. TL was assessed using a modification of quantitative (Q)-FISH in combination with immunofluorescence for CD31 or α-smooth muscle actin to detect EC and VSMC, respectively. Oxidative DNA damage was investigated by immunofluorescence staining for 7, 8-dihydro-8-oxo-2'-deoxyguanosine (8-oxo-dG). Telomeres were found to be significantly shortened in EC, VSMC, keratinocytes and blood lymphocytes from AAA patients compared to matched controls. 8-oxo-dG immunoreactivity, indicative of oxidative DNA damage, was detected at higher levels in all of the above cell types from AAA patients compared to matched controls. Increased DNA double strand breaks were detected in AAA patients vs controls by nuclear staining for γ-H2AX histone. There was statistically significant inverse correlation between TL and accumulation of oxidative DNA damage in blood lymphocytes from AAA patients. This study shows for the first time that EC and VSMC from AAA have shortened telomeres and oxidative DNA damage. Similar findings were obtained with circulating lymphocytes and keratinocytes, indicating the systemic nature of the disease. Potential translational implications of these findings are discussed.

Oxidative DNA damage and its repair in rat spleen following subchronic exposure to aniline

PubMed Central

Ma, Huaxian; Wang, Jianling; Abdel-Rahman, Sherif Z.; Boor, Paul J.; Khan, M. Firoze

2008-01-01

The mechanisms by which aniline exposure elicits splenotoxic response, especially the tumorigenic response, are not well-understood. Splenotoxicity of aniline is associated with iron overload and generation of reactive oxygen species (ROS) which can cause oxidative damage to DNA, proteins and lipids (oxidative stress). 8-Hydroxy-2’-deoxyguanosine (8-OHdG) is one of the most abundant oxidative DNA lesions resulting from ROS, and 8-oxoguanine glycosylase 1 (OGG1), a specific DNA glycosylase/lyase enzyme, plays a key role in the removal of 8-OHdG adducts. This study focused on examining DNA damage (8-OHdG) and repair (OGG1) in the spleen in an experimental condition preceding a tumorigenic response. To achieve that, male Sprague-Dawley rats were subchronically exposed to aniline (0.5 mmol/kg/day via drinking water for 30 days), while controls received drinking water only. Aniline treatment led to a significant increase in splenic oxidative DNA damage, manifested as a 2.8-fold increase in 8-OHdG levels. DNA repair activity, measured as OGG1 base excision repair (BER) activity, increased by ~1.3 fold in the nuclear protein extracts (NE) and ~1.2 fold in the mitochondrial protein extracts (ME) of spleens from aniline-treated rats as compared to the controls. Real-time PCR analysis for OGG1 mRNA expression in the spleen revealed a 2-fold increase in expression in aniline-treated rats than the controls. Likewise, OGG1 protein expression in the NEs of spleens from aniline-treated rats was ~1.5 fold higher, whereas in the MEs it was ~1.3 fold higher than the controls. Aniline treatment also led to stronger immunostaining for both 8-OHdG and OGG1 in the spleens, confined to the red pulp areas. It is thus evident from our studies that aniline-induced oxidative stress is associated with increased oxidative DNA damage. The BER pathway was also activated, but not enough to prevent the accumulation of oxidative DNA damage (8-OHdG). Accumulation of mutagenic oxidative DNA lesions in the spleen following exposure to aniline could play a critical role in the tumorigenic process. PMID:18793663

Low pressure bottom-up synthesis of metal@oxide and oxide nanoparticles: control of structure and functional properties

NASA Astrophysics Data System (ADS)

D'Addato, Sergio; Chiara Spadaro, Maria

2018-03-01

Experimental activity on core@shell, metal@oxide, and oxide nanoparticles (NPs) grown with physical synthesis, and more specifically by low pressure gas aggregation sources (LPGAS) is reviewed, through a selection of examples encompassing some potential applications in nanotechnology. After an introduction to the applications of NPs, a brief description of the main characteristics of the growth process of clusters and NPs in LPGAS is given. Thereafter, some relevant case studies are reported: • Formation of native oxide shells around the metal cores in core@shell NPs. • Experimental efforts to obtain magnetic stabilization in magnetic core@shell NPs by controlling their structure and morphology. • Recent advancements in NP source design and new techniques of co-deposition, with relevant results in the realization of NPs with a greater variety of functionalities. • Recent results on reducible oxide NPs, with potentialities in nanocatalysis, energy storage, and other applications. Although this list is far from being exhaustive, the aim of the authors is to provide the reader a descriptive glimpse into the physics behind the growth and studies of low pressure gas-phase synthesized NPs, with their ever-growing potentialities for the rational design of new functional materials.

Human plasma metabolic profiles of benzydamine, a flavin-containing monooxygenase probe substrate, simulated with pharmacokinetic data from control and humanized-liver mice.

PubMed

Yamazaki-Nishioka, Miho; Shimizu, Makiko; Suemizu, Hiroshi; Nishiwaki, Megumi; Mitsui, Marina; Yamazaki, Hiroshi

2018-02-01

1. Benzydamine is used clinically as a nonsteroidal anti-inflammatory drug in oral rinses and is employed in preclinical research as a flavin-containing monooxygenase (FMO) probe substrate. In this study, plasma concentrations of benzydamine and its primary N-oxide and N-demethylated metabolites were investigated in control TK-NOG mice, in humanized-liver mice, and in mice whose liver cells had been ablated with ganciclovir. 2. Following oral administration of benzydamine (10 mg/kg) in humanized-liver TK-NOG mice, plasma concentrations of benzydamine N-oxide were slightly higher than those of demethyl benzydamine. In contrast, in control and ganciclovir-treated TK-NOG mice, concentrations of demethyl benzydamine were slightly higher than those of benzydamine N-oxide. 3. Simulations of human plasma concentrations of benzydamine and its N-oxide were achieved using simplified physiologically based pharmacokinetic models based on data from control TK-NOG mice and from reported benzydamine concentrations after low-dose administration in humans. Estimated clearance rates based on data from humanized-liver and ganciclovir-treated TK-NOG mice were two orders magnitude high. 4. The pharmacokinetic profiles of benzydamine were different for control and humanized-liver TK-NOG mice. Humanized-liver mice are generally accepted human models; however, drug oxidation in mouse kidney might need to be considered when probe substrates undergo FMO-dependent drug oxidation in mouse liver and kidney.

Metformin does not affect postabsorptive hepatic free fatty acid uptake, oxidation or resecretion in humans: A 3-month placebo-controlled clinical trial in patients with type 2 diabetes and healthy controls.

PubMed

Gormsen, Lars C; Søndergaard, Esben; Christensen, Nana L; Jakobsen, Steen; Nielsen, Erik H T; Munk, Ole L; Tolbod, Lars P; Jessen, Niels; Nielsen, Søren

2018-06-01

To explore whether the pre-clinical findings that metformin improves lipid metabolism, possibly through modulation of intrahepatic partitioning of fatty acids towards oxidation and away from re-esterification and resecretion as triglycerides (TGs), can be translated to a human setting. We performed a 3-month randomized, placebo-controlled, parallel-group clinical trial in patients with type 2 diabetes (T2D; n = 24) and healthy controls (n = 12). Patients with T2D received either placebo (placebo group) or 1000 mg metformin twice daily (metformin group), while healthy subjects were all treated with metformin (control group). Hepatic fatty acid metabolism was measured by [ 11 C]palmitate positron-emission tomography, hepatic TG secretion and peripheral oxidation by ex vivo labelled [1- 14 C]VLDL-TG and VLDL particle size by TG/apolipoprotein B ratio. Body composition was assessed by dual-energy X-ray and whole-body lipid oxidation by indirect calorimetry. Metformin treatment for 3 months produced the anticipated decrease in fasting plasma glucose (FPG) in the metformin group (FPG 7.9 ± 1.8 mM [study day 1] vs 6.4 ± 1.1 mM [study day 2]), whereas patients in the placebo group and healthy controls had similar FPG levels before and after the trial (mixed model group vs time interaction; P = .003); however, contrary to our hypothesis, metformin treatment did not affect hepatic lipid metabolism or peripheral oxidation. The observed beneficial effects on lipid metabolism during metformin treatment in humans appear to be secondary to long-term alterations in body composition or glucose homeostasis. © 2018 John Wiley & Sons Ltd.

Local and systemic oxidant/antioxidant status before and during lung cancer radiotherapy

PubMed Central

Crohns, Marika; Saarelainen, Seppo; Kankaanranta, Hannu; Moilanen, Eeva; Alho, Hannu; Kellokumpu-Lehtinen, Pirkko

2009-01-01

To examine local and systemic oxidative status of lung cancer (LC) and oxidant effects of radiotherapy (RT), this study evaluated antioxidants and markers of oxidative and nitrosative stress in bronchoalveolar lavage (BAL) fluid and in the blood of 36 LC patients and 36 non-cancer controls at baseline and during and after RT for LC. LC patients had higher baseline serum urate, plasma nitrite and lower serum oxidized proteins than controls (p = 0.016, p < 0.001 and p = 0.027, respectively), but BAL fluid oxidative stress markers were similar. RT tended to raise some antioxidants, however, significant increases were seen in serum urate, conjugated dienes and TBARS (p = 0.044, p = 0.034 and p = 0.004, respectively) 3 months after RT. High urate at baseline may compensate against the oxidative stress caused by LC. RT shifts the oxidant/antioxidant balance towards lipid peroxidation, although the antioxidant defense mechanisms of the body appear to counteract the increased oxidative stress rather effectively. PMID:19444690

Electrolysed reduced water decreases reactive oxygen species-induced oxidative damage to skeletal muscle and improves performance in broiler chickens exposed to medium-term chronic heat stress.

PubMed

Azad, M A K; Kikusato, M; Zulkifli, I; Toyomizu, M

2013-01-01

1. The present study was designed to achieve a reduction of reactive oxygen species (ROS)-induced oxidative damage to skeletal muscle and to improve the performance of broiler chickens exposed to chronic heat stress. 2. Chickens were given a control diet with normal drinking water, or diets supplemented with cashew nut shell liquid (CNSL) or grape seed extract (GSE), or a control diet with electrolysed reduced water (ERW) for 19 d after hatch. Thereafter, chickens were exposed to a temperature of either 34°C continuously for a period of 5 d, or maintained at 24°C, on the same diets. 3. The control broilers exposed to 34°C showed decreased weight gain and feed consumption and slightly increased ROS production and malondialdehyde (MDA) concentrations in skeletal muscle. The chickens exposed to 34°C and supplemented with ERW showed significantly improved growth performance and lower ROS production and MDA contents in tissues than control broilers exposed to 34°C. Following heat exposure, CNSL chickens performed better with respect to weight gain and feed consumption, but still showed elevated ROS production and skeletal muscle oxidative damage. GSE chickens did not exhibit improved performance or reduced skeletal muscle oxidative damage. 4. In conclusion, this study suggests that ERW could partially inhibit ROS-induced oxidative damage to skeletal muscle and improve growth performance in broiler chickens under medium-term chronic heat treatment.

Patterning and reduction of graphene oxide using femtosecond-laser irradiation

NASA Astrophysics Data System (ADS)

Kang, SeungYeon; Evans, Christopher C.; Shukla, Shobha; Reshef, Orad; Mazur, Eric

2018-07-01

Graphene has emerged as one of the most versatile materials ever discovered due to its extraordinary electronic, optical, thermal, and mechanical properties. However, device fabrication is a well-known challenge and requires novel fabrication methods to realize the complex integration of graphene-based devices. Here, we demonstrate direct laser writing of reduced graphene oxide using femtosecond-laser irradiation at λ = 795 nm. We perform a systematic study of the reduction process of graphene oxide to graphene by varying both the laser fluence and the pulse repetition rate. Our observations show that the reduction has both thermal and non-thermal features, and suggest that we can achieve better resolution and conductivity using kHz pulse trains than using MHz pulse trains or a continuous wave laser. Our reduced graphene oxide lines written at 10-kHz exhibit a 5 order-of-magnitude decrease in resistivity compared to a non-irradiated control sample. This study provides new insight into the reduction process of graphene oxide and opens doors to achieving a high degree of flexibility and control in the fabrication of graphene layers.

Role of calreticulin in the sensitivity of myocardiac H9c2 cells to oxidative stress caused by hydrogen peroxide.

PubMed

Ihara, Yoshito; Urata, Yoshishige; Goto, Shinji; Kondo, Takahito

2006-01-01

Calreticulin (CRT), a Ca2+-binding molecular chaperone in the endoplasmic reticulum, plays a vital role in cardiac physiology and pathology. Oxidative stress is a main cause of myocardiac apoptosis in the ischemic heart, but the function of CRT under oxidative stress is not fully understood. In the present study, the effect of overexpression of CRT on susceptibility to apoptosis under oxidative stress was examined using myocardiac H9c2 cells transfected with the CRT gene. Under oxidative stress due to H2O2, the CRT-overexpressing cells were highly susceptible to apoptosis compared with controls. In the overexpressing cells, the levels of cytoplasmic free Ca2+ ([Ca2+]i) were significantly increased by H2O2, whereas in controls, only a slight increase was observed. The H2O2-induced apoptosis was enhanced by the increase in [Ca2+]i caused by thapsigargin in control cells but was suppressed by BAPTA-AM, a cell-permeable Ca2+ chelator in the CRT-overexpressing cells, indicating the importance of the level of [Ca2+]i in the sensitivity to H2O2-induced apoptosis. Suppression of CRT by the introduction of the antisense cDNA of CRT enhanced cytoprotection against oxidative stress compared with controls. Furthermore, we found that the levels of activity of calpain and caspase-12 were elevated through the regulation of [Ca2+]i in the CRT-overexpressing cells treated with H2O2 compared with controls. Thus we conclude that the level of CRT regulates the sensitivity to apoptosis under oxidative stress due to H2O2 through a change in Ca2+ homeostasis and the regulation of the Ca2+-calpain-caspase-12 pathway in myocardiac cells.

Oxidative stress markers imbalance in late-life depression.

PubMed

Diniz, Breno S; Mendes-Silva, Ana Paula; Silva, Lucelia Barroso; Bertola, Laiss; Vieira, Monica Costa; Ferreira, Jessica Diniz; Nicolau, Mariana; Bristot, Giovana; da Rosa, Eduarda Dias; Teixeira, Antonio L; Kapczinski, Flavio

2018-03-20

Oxidative stress has been implicated in the pathophysiology of mood disorders in young adults. However, there is few data to support its role in the elderly. The primary aim of this study was to evaluate whether subjects with late-life depression (LLD) presented with changes in oxidative stress response in comparison with the non-depressed control group. We then explored how oxidative stress markers associated with specific features of LLD, in particular cognitive performance and age of onset of major depressive disorder in these individuals. We included a convenience sample of 124 individuals, 77 with LLD and 47 non-depressed subjects (Controls). We measure the plasma levels of 6 oxidative stress markers: thiobarbituric acid reactive substances (TBARS), protein carbonil content (PCC), free 8-isoprostane, glutathione peroxidase (GPx) activity, glutathione reductase (GR) activity, and glutathione S-transferase (GST) activity. We found that participants with LLD had significantly higher free 8-isoprostane levels (p = 0.003) and lower glutathione peroxidase activity (p = 0.006) compared to controls. Free 8-isoprostane levels were also significantly correlated with worse scores in the initiation/perseverance (r = -0.24, p = 0.01), conceptualization (r = -0.22, p = 0.02) sub-scores, and the total scores (r = -0.21, p = 0.04) on the DRS. Our study provides robust evidence of the imbalance between oxidative stress damage, in particular lipid peroxidation, and anti-oxidative defenses as a mechanism related to LLD, and cognitive impairment in this population. Interventions aiming to reduce oxidative stress damage can have a potential neuroprotective effect for LLD subjects. Copyright © 2018 Elsevier Ltd. All rights reserved.

Reflectometry-Ellipsometry Reveals Thickness, Growth Rate, and Phase Composition in Oxidation of Copper.

PubMed

Diaz Leon, Juan J; Fryauf, David M; Cormia, Robert D; Zhang, Min-Xian Max; Samuels, Kathryn; Williams, R Stanley; Kobayashi, Nobuhiko P

2016-08-31

The oxidation of copper is a complicated process. Copper oxide develops two stable phases at room temperature and standard pressure (RTSP): cuprous oxide (Cu2O) and cupric oxide (CuO). Both phases have different optical and electrical characteristics that make them interesting for applications such as solar cells or resistive switching devices. For a given application, it is necessary to selectively control oxide thickness and cupric/cuprous oxide phase volume fraction. The thickness and composition of a copper oxide film growing on the surface of copper widely depend on the characteristics of as-deposited copper. In this Research Article, two samples, copper films prepared by two different deposition techniques, electron-beam evaporation and sputtering, were studied. As the core part of the study, the formation of the oxidized copper was analyzed routinely over a period of 253 days using spectroscopic polarized reflectometry-spectroscopic ellipsometry (RE). An effective medium approximation (EMA) model was used to fit the RE data. The RE measurements were complemented and validated by using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and X-ray diffraction (XRD). Our results show that the two samples oxidized under identical laboratory ambient conditions (RTSP, 87% average relative humidity) developed unique oxide films following an inverse-logarithmic growth rate with thickness and composition different from each other over time. Discussion is focused on the ability of RE to simultaneously extract thickness (i.e., growth rate) and composition of copper oxide films and on plausible physical mechanisms responsible for unique oxidation habits observed in the two copper samples. It appears that extended surface characteristics (i.e., surface roughness and grain boundaries) and preferential crystalline orientation of as-deposited polycrystalline copper films control the growth kinetics of the copper oxide film. Analysis based on a noncontact and nondestructive measurement, such as RE, to extract key material parameters is beneficial for conveniently understanding the oxidation process that would ultimately enable copper oxide-based devices at manufacturing scales.

Natural antioxidant ice cream acutely reduces oxidative stress and improves vascular function and physical performance in healthy individuals.

PubMed

Sanguigni, Valerio; Manco, Melania; Sorge, Roberto; Gnessi, Lucio; Francomano, Davide

2017-01-01

The formation of reactive oxygen species (ROS) contributes to the pathogenesis and progression of several diseases. Polyphenols have been shown to be beneficial against ROS. The aim of this study was to evaluate the effects of a natural antioxidant ice cream on oxidative stress, vascular function, and physical performance. In this controlled, single-blind, crossover study, 14 healthy individuals were randomized to consume 100 g of either antioxidant ice cream containing dark cocoa powder and hazelnut and green tea extracts or milk chocolate ice cream (control ice cream). Participants were studied at baseline and 2 h after ingesting ice cream. Serum polyphenols, antioxidant status (ferric-reducing ability of plasma [FRAP]), nitric oxide (NOx) bioavailability, markers of oxidative stress (determination of reactive oxygen metabolites [d-ROMs] and hydrogen peroxide [H 2 O 2 ]), endothelium function (flow-mediated dilation [FMD] and reactive hyperemia index [RHI]), and exercise tolerance (stress test) were assessed, and the double product was measured. Serum polyphenols (P < 0.001), NOx (P < 0.001), FRAP (P < 0.005), FMD (P < 0.001), and RHI (P < 0.05) increased significantly, oxidative stress decreased (d-Roms, P < 0.001; H 2 O 2 , P < 0.001), and the double product (P < 0.001) was improved only after antioxidant ice cream ingestion. No changes were found after control ice cream ingestion. To our knowledge, this is the first study to demonstrate that a natural ice cream rich in polyphenols acutely improved vascular function and physical performance in healthy individuals through a reduction in oxidative stress. Copyright © 2016 Elsevier Inc. All rights reserved.

Oxidation of High-temperature Alloy Wires in Dry Oxygen and Water Vapor

NASA Technical Reports Server (NTRS)

Opila, Elizabeth J.; Lorincz, Jonathan A.; DeMange, Jeffrey J.

2004-01-01

Small diameter wires (150 to 250 microns) of the high temperature alloys Haynes 188, Haynes 230, Haynes 230, Haynes 214, Kanthal Al and PM2000 were oxidized at 1204 C in dry oxygen or 50% H2O /50% O2 for 70 Hours. The oxidation kinetics were monitored using a thermogravimetric technique. Oxide phase composition and morphology of the oxidized wires were determined by X-ray diffraction,field emission scanning electron microscopy, and energy dispersive spectroscopy. The alumina-forming alloys, Kanthal Al and PM2000, out-performed the chromia-forming alloys under this conditions. PM2000 was recommended as the most promising candidate for advanced hybrid seal applications for space reentry control surface seals or hypersonic propulsion system seals. This study also demonstrated that thermogravimetric analysis of small diameter wires is a powerful technique for the study of oxide volatility, oxide adherence, and breakaway oxidation.

Salivary DNA and markers of oxidative stress in patients with chronic periodontitis.

PubMed

Baňasová, Lenka; Kamodyová, Natália; Janšáková, Katarína; Tóthová, Ľubomíra; Stanko, Peter; Turňa, Ján; Celec, Peter

2015-03-01

Previous observational studies have shown that periodontal status is associated with salivary markers of oxidative damage. A direct comparison of periodontitis patients and controls using a wide palette of salivary markers of oxidative stress is lacking. Characteristics of salivary DNA in periodontitis are unknown. The aim of this study was to compare the salivary markers of oxidative stress and characteristics of salivary DNA between patients with chronic periodontitis and periodontitis-free controls. Saliva was collected from 23 patients with chronic periodontitis and 19 periodontitis-free controls. All participants underwent a clinical periodontal examination. Markers of oxidative and carbonyl stress were measured in saliva. Human and bacterial DNA was quantified, and human DNA integrity was assessed. Salivary thiobarbituric acid-reacting substances were higher in patients than in controls; at least in men, the difference was significant (p < 0.01). In women, patients had significantly lower salivary antioxidant status (p < 0.001). No quantitative differences were found regarding salivary DNA. Tendencies towards reduced DNA integrity were found in periodontitis patients. The results confirmed the association of salivary thiobarbituric acid-reacting substances with periodontitis. Lipid peroxidation in periodontitis seems to be caused by increased production of reactive oxygen species in men and by decreased antioxidant status in women. Whether lower salivary DNA integrity is involved in the pathogenesis of periodontitis remains to be elucidated. Salivary thiobarbituric acid-reacting substances are associated with periodontitis at least on a population level. Sex-specific causes of lipid peroxidation might point towards different pathogenic mechanisms.

Humic Acid-Oxidizing, Nitrate-Reducing Bacteria in Agricultural Soils

PubMed Central

Van Trump, J. Ian; Wrighton, Kelly C.; Thrash, J. Cameron; Weber, Karrie A.; Andersen, Gary L.; Coates, John D.

2011-01-01

ABSTRACT This study demonstrates the prevalence, phylogenetic diversity, and physiology of nitrate-reducing microorganisms capable of utilizing reduced humic acids (HA) as electron donors in agricultural soils. Most probable number (MPN) enumeration of agricultural soils revealed large populations (104 to 106 cells g−1 soil) of microorganisms capable of reducing nitrate while oxidizing the reduced HA analog 2,6-anthrahydroquinone disulfonate (AH2DS) to its corresponding quinone. Nitrate-dependent HA-oxidizing organisms isolated from agricultural soils were phylogenetically diverse and included members of the Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. Advective up-flow columns inoculated with corn plot soil and amended with reduced HA and nitrate supported both HA oxidation and enhanced nitrate reduction relative to no-donor or oxidized HA controls. The additional electron donating capacity of reduced HA could reasonably be attributed to the oxidation of reduced functional groups. Subsequent 16S rRNA gene-based high-density oligonucleotide microarray (PhyloChip) indicated that reduced HA columns supported the development of a bacterial community enriched with members of the Acidobacteria, Firmicutes, and Betaproteobacteria relative to the no-donor control and initial inoculum. This study identifies a previously unrecognized role for HA in stimulating denitrification processes in saturated soil systems. Furthermore, this study indicates that reduced humic acids impact soil geochemistry and the indigenous bacterial community composition. PMID:21750120

Inverse oxide/metal catalysts in fundamental studies and practical applications: A perspective of recent developments

DOE PAGES

Rodriguez, José A.; Liu, Ping; Graciani, Jesús; ...

2016-06-21

Inverse oxide/metal catalysts have shown to be excellent systems for studying the role of the oxide and oxide–metal interface in catalytic reactions. These systems can have special structural and catalytic properties due to strong oxide–metal interactions difficult to attain when depositing a metal on a regular oxide support. Oxide phases that are not seen or are metastable in a bulk oxide can become stable in an oxide/metal system opening the possibility for new chemical properties. Using these systems, it has been possible to explore fundamental properties of the metal–oxide interface (composition, structure, electronic state), which determine catalytic performance in themore » oxidation of CO, the water–gas shift and the hydrogenation of CO 2 to methanol. Recently, there has been a significant advance in the preparation of oxide/metal catalysts for technical or industrial applications. In conclusion, one goal is to identify methods able to control in a precise way the size of the deposited oxide particles and their structure on the metal substrate.« less

XYLITOL IMPROVES ANTI-OXIDATIVE DEFENSE SYSTEM IN SERUM, LIVER, HEART, KIDNEY AND PANCREAS OF NORMAL AND TYPE 2 DIABETES MODEL OF RATS.

PubMed

Chukwuma, Chika Ifeanyi; Islam, Shahidul

2017-05-01

The present study investigated the anti-oxidative effects of xylitol both in vitro and in vivo in normal and type 2 diabetes (T2D) rat model. Free radical scavenging and ferric reducing potentials of different concentrations of xylitol were investigated in vitro. For in vivo study, six weeks old male Sprague-Dawley rats were divided into four groups, namely: Normal Control (NC), Diabetic Control (DBC), Normal Xylitol (NXYL) and Diabetic Xylitol (DXYL). T2D was induced in the DBC and DXYL groups. After the confirmation of diabetes, a 10% xylitol solution was supplied instead of drinking water to NXYL and DXYL, while normal drinking water was supplied to NC and DBC ad libitum. After five weeks intervention period, the animals were sacri- ficed and thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH) concentrations as well as superoxide dismutase, catalase glutathione reductase and glutathione peroxidase activities were determined in the liver, heart, kidney, pancreatic tissues and serum samples. Xylitol exhibited significant (p < 0.05) in vitro nitric oxide and hydroxyl radical scavenging and ferric reducing activities. In vivo study revealed significant (p < 0.05) reduction in TBARS concentrations in the xylitol consuming groups compared to their respective controls. Significant (p < 0.05) increase in GSH levels and antioxidant enzyme activities were observed in analyzed tissues and serum of xylitol-fed animals compared to their respective controls. Results of this study indicate that xylitol has strong anti-oxidative potential against T2D-associated oxidative stress. Hence, xylitol can be used as a potential supplement in diabetic foods and food products.

The Association between the Epicardial Adipose Tissue Thickness and Oxidative Stress Parameters in Isolated Metabolic Syndrome Patients: A Multimarker Approach

PubMed Central

Demir, Bulent; Demir, Esra; Acıksarı, Gonul; Uygun, Turgut; Utku, Irem Kırac; Gedikbasi, Asuman; Caglar, Ilker Murat; Pirhan, Osman; Tureli, Hande Oktay; Oflar, Ersan; Ungan, İsmail; Ciftci, Serkan; Karakaya, Osman

2014-01-01

The risk for cardiovascular diseases and type 2 diabetes mellitus significantly increases in the patient population with metabolic syndrome (MeS). The present study aimed to investigate the association between the epicardial adipose tissue thickness (EATT) and the oxidative stress parameters in MeS patients. The study included 181 patients as a patient group of 92 consecutive patients with MeS and a control group of 89 consecutive patients with similar age and gender. EATT was evaluated by transthoracic echocardiography. Serum levels of total oxidant status (TOS), total antioxidative capacity (TAS), paraoxonase-1 (PON-1), and arylesterase activities were measured. EATT was higher in the MeS group compared to the control group (6.0 ± 2.0 mm and 4.0 ± 1.0 mm, resp.; P < 0.001). The level of TOS was higher in the MeS group compared to the control group (P < 0.001). Additionally, the TAS level was higher in the MeS group compared to the control group (P < 0.001). Furthermore, the serum levels of PON-1 and arylesterase were lower in the MeS group compared to the control group (P < 0.001). EAT may cause an increased risk of cardiovascular diseases by leading to increased oxidative stress in patients with MeS. PMID:25530760

Pulmonary dysfunctions, oxidative stress and DNA damage in brick kiln workers.

PubMed

Kaushik, R; Khaliq, F; Subramaneyaan, M; Ahmed, R S

2012-11-01

Brick kilns in the suburban areas in developing countries pose a big threat to the environment and hence the health of their workers and people residing around them. The present study was planned to assess the lung functions, oxidative stress parameters and DNA damage in brick kiln workers. A total of 31 male subjects working in brick kiln, and 32 age, sex and socioeconomic status matched controls were included in the study. The lung volumes, capacities and flow rates, namely, forced expiratory volume in first second (FEV(1)), forced vital capacity (FVC), FEV(1)/FVC, expiratory reserve volume, inspiratory capacity (IC), maximal expiratory flow when 50% of FVC is remaining to be expired, maximum voluntary ventilation, peak expiratory flow rate and vital capacity were significantly decreased in the brick kiln workers. Increased oxidative stress as evidenced by increased malonedialdehyde levels and reduced glutathione content, glutathione S-transferase activity and ferric reducing ability of plasma were observed in the study group when compared with controls. Our results indicate a significant correlation between oxidative stress parameters and pulmonary dysfunction, which may be due to silica-induced oxidative stress and resulting lung damage.

Natural attenuation process via microbial oxidation of arsenic in a high Andean watershed.

PubMed

Leiva, Eduardo D; Rámila, Consuelo d P; Vargas, Ignacio T; Escauriaza, Cristian R; Bonilla, Carlos A; Pizarro, Gonzalo E; Regan, John M; Pasten, Pablo A

2014-01-01

Rivers in northern Chile have arsenic (As) concentrations at levels that are toxic for humans and other organisms. Microorganism-mediated redox reactions have a crucial role in the As cycle; the microbial oxidation of As (As(III) to As(V)) is a critical transformation because it favors the immobilization of As in the solid phase. We studied the role of microbial As oxidation for controlling the mobility of As in the extreme environment found in the Chilean Altiplano (i.e., > 4000 meters above sea level (masl) and < 310 mm annual rainfall), which are conditions that have rarely been studied. Our model system was the upper Azufre River sub-basin, where the natural attenuation of As from hydrothermal discharge (pH 4-6) was observed. As(III) was actively oxidized by a microbial consortium, leading to a significant decrease in the dissolved As concentrations and a corresponding increase in the sediment's As concentration downstream of the hydrothermal source. In-situ oxidation experiments demonstrated that the As oxidation required biological activity, and microbiological molecular analysis confirmed the presence of As(III)-oxidizing groups (aroA-like genes) in the system. In addition, the pH measurements and solid phase analysis strongly suggested that the As removal mechanism involved adsorption or coprecipitation with Fe-oxyhydroxides. Taken together, these results indicate that the microorganism-mediated As oxidation contributed to the attenuation of As concentrations and the stabilization of As in the solid phase, therefore controlling the amount of As transported downstream. This study is the first to demonstrate the microbial oxidation of As in Altiplano basins and its relevance in the immobilization of As. © 2013.

Thermal oxidation and nitridation of Si nanowalls prepared by metal assisted chemical etching

NASA Astrophysics Data System (ADS)

Behera, Anil K.; Viswanath, R. N.; Lakshmanan, C.; Polaki, S. R.; Sarguna, R. M.; Mathews, Tom

2018-04-01

Silicon nanowalls with controlled orientation have been prepared using metal assisted chemical etching process. Thermal oxidation and nitridation processes have been carried out on the prepared silicon nanowalls under a control flow of oxygen/nitrogen gases independently at 1050°C for 900s. The morphology and structural properties of the as-prepared, oxidized and nitridated silicon nanowalls have been studied using the scanning electron microscopy and the Grazing incident X-ray diffraction techniques. The results obtained from the analysis of X-ray diffraction patterns and the microscopy images are discussed.

Electrochemical oxidation of ciprofloxacin in two different processes: the electron transfer process on the anode surface and the indirect oxidation process in bulk solutions.

PubMed

Shen, Bo; Wen, Xianghua; Korshin, Gregory V

2018-05-14

Herein, the rotating disk electrode technique was used for the first time to investigate the effects of mass-transfer limitations and pH on the electrochemical oxidation of CPX, to determine the kinetics of CPX oxidation and to explore intrinsic mechanisms during the electron transfer process. Firstly, cyclic voltammetry revealed that an obvious irreversible CPX oxidation peak was observed within the potential window from 0.70 to 1.30 V at all pHs. Based on the Levich equation, the electrochemical oxidation of CPX in the electron transfer process was found to be controlled by both diffusion and kinetic processes when pH = 2, 5, 7 and 9; the diffusion coefficient of CPX at pH = 2 was calculated to be 1.5 × 10-7 cm2 s-1. Kinetic analysis indicated that the reaction on the electrode surface was adsorption-controlled compared to a diffusion process; the surface concentration of electroactive species was estimated to be 1.15 × 10-9 mol cm-2, the standard rate constant of the surface reaction was calculated to be 1.37 s-1, and CPX oxidation was validated to be a two-electron transfer process. Finally, a possible CPX oxidation pathway during the electron transfer process was proposed. The electrochemical degradation of CPX on a Ti-based anode was also conducted subsequently to investigate the electrochemical oxidation of CPX in the indirect oxidation process in bulk solutions. The effects of pH and current density were determined and compared to related literature results. The oxidation of CPX at different pHs is believed to be the result of a counterbalance between favorable and unfavorable factors, namely electromigration and side reactions of oxygen evolution, respectively. The effects of current density indicated a diffusion- and reaction-controlled process at low currents followed by a reaction-controlled process at high currents. The results presented in this study provide better understanding of the electrochemical oxidation of CPX and would enable the development of new treatment methods based on electrochemistry.

Control of arsenic mobilization in paddy soils by manganese and iron oxides.

PubMed

Xu, Xiaowei; Chen, Chuan; Wang, Peng; Kretzschmar, Ruben; Zhao, Fang-Jie

2017-12-01

Reductive mobilization of arsenic (As) in paddy soils under flooded conditions is an important reason for the relatively high accumulation of As in rice, posing a risk to food safety and human health. The extent of As mobilization varies widely among paddy soils, but the reasons are not well understood. In this study, we investigated As mobilization in six As-contaminated paddy soils (total As ranging from 73 to 122 mg kg -1 ) in flooded incubation and pot experiments. Arsenic speciation in the solution and solid phases were determined. The magnitude of As mobilization into the porewater varied by > 100 times among the six soils. Porewater As concentration correlated closely with the concentration of oxalate-extractable As, suggesting that As associated with amorphous iron (oxyhydr)oxides represents the potentially mobilizable pool of As under flooded conditions. Soil containing a high level of manganese oxides showed the lowest As mobilization, likely because Mn oxides retard As mobilization by slowing down the drop of redox potential upon soil flooding and maintaining a higher arsenate to arsenite ratio in the solid and solution phases. Additions of a synthetic Mn oxide (hausmannite) to two paddy soils increased arsenite oxidation, decreased As mobilization into the porewater and decreased As concentrations in rice grain and straw. Consistent with previous studies using simplified model systems or pure mineral phases, the present study shows that Mn oxides and amorphous Fe (oxyhydr)oxides are important factors controlling reductive As mobilization in As-contaminated paddy soils. In addition, this study also suggests a potential mitigation strategy using exogenous Mn oxides to decrease As uptake by rice in paddy soils containing low levels of indigenous Mn oxides, although further work is needed to verify its efficacy and possible secondary effects under field conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Peroxisomal fatty acid oxidation and inhibitors of the mitochondrial carnitine palmitoyltransferase I in isolated rat hepatocytes.

PubMed Central

Skorin, C; Necochea, C; Johow, V; Soto, U; Grau, A M; Bremer, J; Leighton, F

1992-01-01

Fatty acid oxidation was studied in the presence of inhibitors of carnitine palmitoyltransferase I (CPT I), in normal and in peroxisome-proliferated rat hepatocytes. The oxidation decreased in mitochondria, as expected, but in peroxisomes it increased. These two effects were seen, in variable proportions, with (+)-decanoylcarnitine, 2-tetradecylglycidic acid (TDGA) and etomoxir. The decrease in mitochondrial oxidation (ketogenesis) affected saturated fatty acids with 12 or more carbon atoms, whereas the increase in peroxisomal oxidation (H2O2 production) affected saturated fatty acids with 8 or more carbon atoms. The peroxisomal increase was sensitive to chlorpromazine, a peroxisomal inhibitor. To study possible mechanisms, palmitoyl-, octanoyl- and acetyl-carnitine acyltransferase activities were measured, in homogenates and in subcellular fractions from control and TDGA-treated cells. The palmitoylcarnitine acyltransferase was inhibited, as expected, but the octanoyltransferase activity also decreased. The CoA derivative of TDGA was synthesized and tentatively identified as being responsible for inhibition of the octanoylcarnitine acyltransferase. These results show that inhibitors of the mitochondrial CPT I may also inhibit the peroxisomal octanoyl transferase; they also support the hypothesis that the octanoyltransferase has the capacity to control or regulate peroxisomal fatty acid oxidation. PMID:1736904

Oxidation products are increased in patients affected by non-segmental generalized vitiligo.

PubMed

Vaccaro, Mario; Bagnato, Gianluca; Cristani, Mariateresa; Borgia, Francesco; Spatari, Giovanna; Tigano, Valeria; Saja, Antonina; Guarneri, Fabrizio; Cannavò, Serafinella P; Gangemi, Sebastiano

2017-08-01

Several lines of evidence support the relevance of reactive oxygen species (ROS) in vitiligo, but the exact role of glycation and oxidation of macromolecules needs to be better addressed. To investigate the involvement of advanced oxidation protein products (AOPPs) and advanced glycation end-products (AGEs), we performed a case-control association study by spectrofluorimetry and spectrophotometry, in 47 patients with non-segmental generalized vitiligo and 47 age- and sex-matched controls. Significantly higher levels of both AOPPs (p < 0.0001) and AGEs (p < 0.0001) were observed in vitiligo patients compared to healthy controls. In vitiligo patients, AGEs and AOPPs serum levels were directly associated with extension, duration of vitiligo, and disease activity. ROS, and in particular AGEs and AOPPs, could represent one of the main biomarkers to assess the onset and progression of vitiligo, due to the potential role as direct inducers of cell damage and also as autoimmunity triggers. Further longitudinal studies involving larger cohorts of patients are required to elucidate the role of oxidation products in the pathogenesis of vitiligo.

Irradiation ageing of CSPE/EPR control command electric cables. Correlation between mechanical properties and oxidation

NASA Astrophysics Data System (ADS)

Calmet, J. F.; Carlin, F.; Nguyen, T. M.; Bousquet, S.; Quinot, P.

2002-03-01

In this paper, correlations between the elongation at break and the oxidation of chlorosulfonated polyethylene and ethylene propylene rubber (EPR) polymers in instrumentation and control cables irradiated at different dose rates are brought to evidence. During irradiation, the following phenomena are observed: an increase of oxygen consumption, a degradation of the mechanical properties and a reduction of the oxidation induction time (OIT) measured for EPR. A correlation between the mechanical properties and the OIT of the EPR has only been established in the case of irradiation at low dose rate. This reveals a difference in the oxidative degradation process at low and high dose rates. This study shows the possibility to assess the ageing of electric cables installed inside nuclear power plants by OIT measurements.

Manganese oxide octahedral molecular sieves: Synthesis, self-assembly, control over morphologies and tunnel structure

NASA Astrophysics Data System (ADS)

Yuan, Jikang

Direct architecture of complex nanostructures is desirable and still remains a challenge in areas of materials science. Due to their size-, shape-dependent electronic and optical properties, much effort has been made to control morphologies of transition metal oxide nanoparticles and to organize them into complicated 3D structures using templates. In particular, manganese oxides have attracted much attention because they have extensive applications in many chemical processes due to their porous structures, acidity, ionexchange, separation, catalysis, and energy storage in secondary batteries. Using organic templates such as trimethylamine (TMA), manganese oxides have been successfully organized into macroscopic rings and helices via sol-gel processes. However, the methods mentioned above all need further purification, so impurities will be avoided. Subsequent procedures are needed to obtain pure products. Thus facile and template-free methods are highly desired for synthesis of manganese oxide nanaoparticles with complex 3D structures. Manganese oxide octahedral molecular sieves (OMS) are a class of microporous transition metallic oxides with various kinds of tunnel structures that can be synthesized via controlling synthetic conditions such as temperature, concentration, pH, and cations. Manganese oxide molecular sieves are semiconducting mixed-valence catalysts that utilize electron transport to catalyze reactions such as selective oxidation of alcohols. OMS has distinct advantages over aluminosilicate molecular sieve materials for applications in catalysis due to the mixed valence character. The synthesis of manganese oxide OMS materials will be much more complicated than those of main group metallic oxides because of different coordination numbers and oxidation states. OMS-type materials with desirable morphologies formed under mild synthetic conditions are highly desirable. Herein, we report a template-free, low temperature preparation of porous cryptomelane-type manganese oxide (OMS-2) 3D nanostructures. The objectives of this research include exploration of new methods to oxidize Mn2+ in aqueous solution either under low-temperature reflux or hydrothermal conditions. Various oxidants were used with precisely controlled synthetic parameters such as temperature, concentrations of starting materials, pH, and kinds of templates. A variety of techniques including powder X-ray diffraction and transmission electron microscopy (TEM) scanning electron microscopy are used to investigate the structures of synthesized materials. Atomic force microscopy (AFM) and scanning electron microscopy are utilized to studying the morphology and topography. The surface areas of the materials is measured by the BET method. Inductively coupled argon plasma atomic emission spectrometer (ICP-AES) are utilized to investigate the chemical composition of the materials. Thermal-stability of the materials is investigated by thermal gravimetric analysis (TGA). The objectives of this research includes exploring new synthetic approach such as oxidation of Mn2+ in aqueous solution by selecting suitable oxidants so as to control redox potential, varying pH of reaction systems, and controlling tunnel structures using hard templates (cations) under hydrothermal conditions.

Mitochondrial Protein Profile in Mice with Low or Excessive Selenium Diets

PubMed Central

Hu, Lianmei; Wang, Congcong; Zhang, Qin; Yan, Hao; Li, Ying; Pan, Jiaqiang; Tang, Zhaoxin

2016-01-01

Dietary selenium putatively prevents oxidative damage, whereas excessive selenium may lead to animal disorder. In this study, we investigated the effects of low and excessive levels of dietary selenium on oxidative stress and mitochondrial proteins in mouse liver. Six to eight week old mice were fed a diet with low, excessive, or moderate (control) levels of selenium (sodium selenite). The selenium concentration and oxidative stress-related parameters in hepatic mitochondria were evaluated. Two-dimensional electrophoresis and mass spectrometry were applied to identify the differentially-expressed proteins associated with dietary selenium. The selenium content of the livers in mice with the low selenium diet was significantly lower than that of the control, while that of mice fed excessive levels was significantly higher. In both groups oxidative stress in hepatic mitochondria was found; accompanied by lower superoxide dismutase (SOD) and glutathione peroxidase (GPX) levels and higher malondialdehyde (MDA) content, compared with the control group. Furthermore, ten proteins in the hepatic mitochondria of the selenium-low or -excessive groups with more than two-fold differences in abundance compared with the control group were identified. The differentially-expressed proteins in hepatic mitochondria may be associated with dietary (low or excessive) selenium-induced oxidative stress. PMID:27428959

Analytical study of mechanisms for nitric oxide formation during combustion of methane in a jet-stirred combustor

NASA Technical Reports Server (NTRS)

Jachimowski, C. J.

1975-01-01

The role of chemical kinetics in the formation of nitric oxide during the combustion of methane was examined analytically by means of a detailed chemical mechanism for the oxidation of methane, for the reaction between hydrocarbon fragments, and for the formation of nitric oxide. By comparing predicted nitric oxide levels with values reported in the literature from jet-stirred combuster experiments, it was determined that the nitric oxide levels observed in fuel-rich flames cannot be described by a mechanism in which the rate of nitric oxide formation is controlled solely by the kinetics of oxygen atom formation. A proposed mechanism for the formation of nitric oxide in methane-rich flames reproduces the observed levels. The oxidation of hydrogen cyanide appears to be an important factor in nitric oxide formation.

Oxide Thermoelectric Materials: A Structure-Property Relationship

NASA Astrophysics Data System (ADS)

Nag, Abanti; Shubha, V.

2014-04-01

Recent demand for thermoelectric materials for power harvesting from automobile and industrial waste heat requires oxide materials because of their potential advantages over intermetallic alloys in terms of chemical and thermal stability at high temperatures. Achievement of thermoelectric figure of merit equivalent to unity ( ZT ≈ 1) for transition-metal oxides necessitates a second look at the fundamental theory on the basis of the structure-property relationship giving rise to electron correlation accompanied by spin fluctuation. Promising transition-metal oxides based on wide-bandgap semiconductors, perovskite and layered oxides have been studied as potential candidate n- and p-type materials. This paper reviews the correlation between the crystal structure and thermoelectric properties of transition-metal oxides. The crystal-site-dependent electronic configuration and spin degeneracy to control the thermopower and electron-phonon interaction leading to polaron hopping to control electrical conductivity is discussed. Crystal structure tailoring leading to phonon scattering at interfaces and nanograin domains to achieve low thermal conductivity is also highlighted.

Effects of N-acetylcysteine on semen parameters and oxidative/antioxidant status.

PubMed

Ciftci, Halil; Verit, Ayhan; Savas, Murat; Yeni, Ercan; Erel, Ozcan

2009-07-01

To examine whether a beneficial effect of N-acetylcysteine (NAC) on semen parameters and oxidative/antioxidant status in idiopathic male infertility exists. The production of reactive oxygen species is a normal physiologic event in various organs. However, overproduction of reactive oxygen species can be detrimental to sperm and has been associated with male infertility. Our study included 120 patients who had attended our clinic and were diagnosed with idiopathic infertility according to medical history and physical and seminal examination findings, as initial evaluations. The patients were divided randomly into 2 groups. Those in the study group (60 men) were given NAC (600 mg/d orally) for 3 months; the control group (60 men) received a placebo. The oxidative status was determined by measuring the total antioxidant capacity, total peroxide and oxidative stress index in plasma samples. The sperm parameters were evaluated after NAC treatment and were compared with those in the control group. NAC had significant improving effects on the volume, motility, and viscosity of semen. After NAC treatment, the serum total antioxidant capacity was greater and the total peroxide and oxidative stress index were lower in the NAC-treated group compared with the control group. These beneficial effects resulted from reduced reactive oxygen species in the serum and reduced viscosity of the semen. No significant differences were found in the number or morphology of the sperm between the 2 groups. We believe that NAC could improve some semen parameters and the oxidative/antioxidant status in patients with male infertility.

In vitro effects of nonesterified fatty acids on bovine neutrophils oxidative burst and viability.

PubMed

Scalia, D; Lacetera, N; Bernabucci, U; Demeyere, K; Duchateau, L; Burvenich, C

2006-01-01

An in vitro study was conducted to examine the influence of nonesterified fatty acids (NEFA) on bovine polymorphonuclear leukocytes (PMN). Eight healthy, midlactating Holstein cows were used as blood donors. Blood PMN were isolated and incubated with a mixture of NEFA, reflecting composition of bovine plasma NEFA at concentrations that were intended to mimic those found in blood of cows undergoing high, moderate, or low lipomobilization intensity (2, 1, 0.5, 0.25, 0.125, and 0.0625 mM). Control samples were incubated in absence of NEFA. Phagocytosis and oxidative burst activities were assessed by a 2-color flow cytometric method, which was based on oxidation of intracellular dihydrorhodamine 123 to green fluorescent rhodamine 123. Oxidative burst products were generated by incubating PMN with Staphylococcus aureus labeled with propidium iodide. A flow cytometric technique was used to detect PMN viability, necrosis, and apoptosis using fluorescein isothiocyanate-labeled annexin-V and propidium iodide. Phagocytic activity was not affected by NEFA. The highest concentration of NEFA (2 mM) was associated with a dramatic increase of phagocytosis-associated oxidative burst activities with a reduction in cell viability (48.0 vs. 97.5% in control samples) and with a marked increase of necrosis (49.4 vs. 0.5% in control samples). Conversely, the mixture of NEFA did not affect the occurrence of apoptosis. Enhancement of the oxidative burst associated with the highest concentration of NEFA might explain the reduced viability and higher percentage of necrosis observed under the same conditions. This study demonstrated a substantial resistance of bovine PMN to an overload of fatty acids. However, observation that the highest concentration of NEFA regulated some PMN functions encourages the possibility of in vivo studies to assess the relationships between intensity of lipomobilization, plasma NEFA, and bovine PMN functions.

Qualitative and quantitative observations of bone tissue reactions to anodised implants.

PubMed

Sul, Young-Taeg; Johansson, Carina B; Röser, Kerstin; Albrektsson, Tomas

2002-04-01

Research projects focusing on biomaterials related factors; the bulk implant material, the macro-design of the implant and the microsurface roughness are routinely being conducted at our laboratories. In this study, we have investigated the bone tissue reactions to turned commercially pure (c.p.) titanium implants with various thicknesses of the oxide films after 6 weeks of insertion in rabbit bone. The control c.p. titanium implants had an oxide thickness of 17-200 nm while the test implants revealed an oxide thickness between 600 and 1000 nm. Routine histological investigations of the tissue reactions around the implants and enzyme histochemical detections of alkaline and acid phosphatase activities demonstrated similar findings around both the control and test implants. In general, the histomorphometrical parameters (bone to implant contact and newly formed bone) revealed significant quantitative differences between the control and test implants. The test implants demonstrated a greater bone response histomorphometrically than control implants and the osteoconductivity was more pronounced around the test implant surfaces. The parameters that differed between the implant surfaces, i.e. the oxide thickness, the pore size distribution, the porosity and the crystallinity of the surface oxides may represent factors that have an influence on the histomorphometrical results indicated by a stronger bone tissue response to the test implant surfaces, with an oxide thickness of more than 600 nm.

An Experimental Approach to Controllably Vary Protein Oxidation While Minimizing Electrode Adsorption for Boron-Doped Diamond Electrochemical Surface Mapping Applications

PubMed Central

McClintock, Carlee S; Hettich, Robert L.

2012-01-01

Oxidative protein surface mapping has become a powerful approach for measuring the solvent accessibility of folded protein structures. A variety of techniques exist for generating the key reagent – hydroxyl radicals – for these measurements; however, these approaches range significantly in their complexity and expense of operation. This research expands upon earlier work to enhance the controllability of boron-doped diamond (BDD) electrochemistry as an easily accessible tool for producing hydroxyl radicals in order to oxidize a range of intact proteins. Efforts to modulate oxidation level while minimizing the adsorption of protein to the electrode involved the use of relatively high flow rates to reduce protein residence time inside the electrochemical flow chamber. Additionally, a different cell activation approach using variable voltage to supply a controlled current allowed us to precisely tune the extent of oxidation in a protein-dependent manner. In order to gain perspective on the level of protein adsorption onto the electrode surface, studies were conducted to monitor protein concentration during electrolysis and gauge changes in the electrode surface between cell activation events. This report demonstrates the successful use of BDD electrochemistry for greater precision in generating a target number of oxidation events upon intact proteins. PMID:23210708

Nitrous oxide for pain management of first trimester surgical abortion -- a randomized controlled pilot study.

PubMed

Singh, Rameet H; Espey, Eve; Carr, Shannon; Pereda, Brenda; Ogburn, Tony; Leeman, Lawrence

2015-02-01

The objective was to determine feasibility of a study comparing mean pain scores between women randomized to nitrous oxide/oxygen (NO) versus oxygen+oral analgesics for trimester surgical abortion. Pilot randomized controlled trial comparing NO (n=10) versus oxygen+oral analgesics (n=10). Feasibility of subject recruitment, and pain and satisfaction scores on a visual analog scale were evaluated. Fifty-seven percent of eligible women participated. Mean pain scores were similar between groups, and mean satisfaction scores were higher for the NO group (77.5 vs. 46.7, P=.048). The majority of eligible women agreed to participate in this study evaluating an uncommon pain control intervention. Copyright © 2015 Elsevier Inc. All rights reserved.

8-isoprostane as Oxidative Stress Marker in Coal Mine Workers.

PubMed

Zimet, Zlatko; Bilban, Marjan; Marc Malovrh, Mateja; Korošec, Peter; Poljšak, Borut; Osredkar, Joško; Šilar, Mira

2016-08-01

This study was to investigate whether working in conditions of elevated concentrations of mine gases (CO2, CO, CH4, DMS) and dust may result in oxidative stress. Coal miners (n=94) from the Velenje Coal mine who were arranged into control group and three groups according to a number of consecutive working days. 8-isoprostane as a biological marker of oxidative stress was measured in exhaled breath condensate (EBC). Miners who worked for three consecutive days had higher 8-isoprostane values in EBC compared to the control group. Gas/dust concentrations and exposure time of a single/two day shift seem too low to trigger immediate oxidative stress. Copyright © 2016 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

Flavin-mediated dual oxidation controls an enzymatic Favorskii-type rearrangement

PubMed Central

Louie, Gordon; Noel, Joseph P.; Baran, Phil S.; Palfey, Bruce; Moore, Bradley S.

2013-01-01

Flavoproteins catalyze a diversity of fundamental redox reactions and are one of the most studied enzyme families1,2. As monooxygenases, they are universally thought to control oxygenation by means of a peroxyflavin species that transfers a single atom of molecular oxygen to an organic substrate1,3,4. Here we report that the bacterial flavoenzyme EncM5,6 catalyzes the peroxyflavin-independent oxygenation-dehydrogenation dual oxidation of a highly reactive poly(β-carbonyl). The crystal structure of EncM with bound substrate mimics coupled with isotope labeling studies reveal previously unknown flavin redox biochemistry. We show that EncM maintains an unanticipated stable flavin oxygenating species, proposed to be a flavin-N5-oxide, to promote substrate oxidation and trigger a rare Favorskii-type rearrangement that is central to the biosynthesis of the antibiotic enterocin. This work provides new insight into the fine-tuning of the flavin cofactor in offsetting the innate reactivity of a polyketide substrate to direct its efficient electrocyclization. PMID:24162851

Mitochondrial oxidative metabolism during respiratory infection in riboflavin deficient mice.

PubMed

Brijlal, S; Lakshmi, A V; Bamji, M S

1999-12-01

Studies in children and mice have shown that respiratory infection alters riboflavin metabolism, resulting in increased urinary loss of this vitamin. This could be due to mobilization of riboflavin from the liver to blood because liver Flavin adenine dinucleotide (FAD) levels were lowered in the mice during infection. To understand the functional implications of lowered hepatic FAD levels during respiratory infection, flavoprotein functions such as oxidative phosphorylation and beta-oxidation of the liver mitochondria were examined during infection in mice. Weanling mice were fed either riboflavin-restricted or control diet for 18 days and then injected with a sublethal dose of Klebsiella pneumoniae. During infection, the state 3 respiratory rate with palmitoyl-L-carnitine and glutamate were significantly lowered (27-29%) in the riboflavin-restricted group, whereas in the control group 10% reduction was observed with palmitoyl-L-carnitine as substrate. A 22% reduction in the respiratory control ratio with palmitoyl-L-carnitine as substrate was observed during infection in the riboflavin-restricted group. The beta-oxidation of palmitoyl-L-carnitine was significantly lowered (29%) in the riboflavin-restricted infected group. The results of the study suggest that the effects of infection on vital physiologic functions were more pronounced in the riboflavin-restricted mice than in the control mice. (c) Elsevier Science Inc. 1999.

In vivo nanotoxicological profile of graphene oxide

NASA Astrophysics Data System (ADS)

Durán, Marcela; Durán, Nelson; Fávaro, Wagner J.

2017-06-01

Graphene oxide, a widely studied nano materials, exhibits numerous beneficial effects in medical devices. The graphene sample Graphene oxide (GO):Single-layer graphene oxide, purity 99%, thickness 0.7-1.2 nm (AFM); ~300-800nm X&Y dimensions is the standard size <450 nm & 1-20 µm lateral dimensions from Cheap Tubes Inc., Bratleboro, USA was selected for this study. Characterization of GO and stability were previously studied. All the assays were carried out at a concentration of 1 mg/mL (stock suspension by ultrasonication)(stable 10 days). In this study the first parameter evaluated was in animal toxicity in acute and chronic responses. The second one was to observe the morphology and histological changes on major organs, like signs of inflammatory areas. A total of 25 rats (Fischer 344) were divide in 5 groups (n = 5 animals): negative control group (NCT); Positive cancer control group (PCCT); GO group-1 (GO 1); GO group-2 (GO 2) and GO group-3 (GO 3), with different concentrations of graphene oxide. All the groups were treated by via intra peritoneal (i.p) administration. Biochemical and histopathology results of acute toxicity showed no alterations. In the chronic toxicity was found deposit sections and morphology alterations in different tissues (inflammations). Genotoxicity was dose dependent of GO. This study gave us the limit concentrations of GO free for any biological study.

Effects of 12-week combined exercise therapy on oxidative stress in female fibromyalgia patients.

PubMed

Sarıfakıoğlu, Banu; Güzelant, Aliye Yıldırım; Güzel, Eda Celik; Güzel, Savaş; Kızıler, Ali Rıza

2014-10-01

The aims of this study were to investigate the effect of exercise therapy on the oxidative stress in fibromyalgia patients and relationship between oxidative stress and fibromyalgia symptoms. Thirty women diagnosed with fibromyalgia according to the American College of Rheumatology preliminary criteria, and 23 healthy women whose age- and weight-matched women were enrolled the study. Pain intensity with visual analog scale (VAS), the number of tender points, the fibromyalgia impact questionnaire (FIQ), the Beck depression inventory (BDI) were evaluated. The oxidative stress parameters thiobarbituric acid reactive substances, protein carbonyls, and nitric oxide, and antioxidant parameters thiols and catalase were investigated in patients and control group. After, combined aerobic and strengthen exercise regimen was given to fibromyalgia group. Exercise therapy consisted of a warming period of 10 min, aerobic exercises period of 20 min, muscle strengthening exercises for 20 min, and 10 min cooling down period. Therapy was lasting 1 h three times per week over a 12-week period. All parameters were reevaluated after the treatment in the patient group. The oxidative stress parameters levels were significantly higher, and antioxidant parameters were significantly lower in patients with fibromyalgia than in the controls. VAS, FIQ, and BDI scores decreased significantly with exercise therapy. The exercise improved all parameters of oxidative stress and antioxidant parameters. Also, all clinical parameters were improved with exercise. We should focus on oxidative stress in the treatment for fibromyalgia with the main objective of reducing oxidative load.

Evaluating OSHA's ethylene oxide standard: exposure determinants in Massachusetts hospitals.

PubMed

LaMontagne, A D; Kelsey, K T

2001-03-01

This study sought to identify determinants of workplace exposures to ethylene oxide to assess the effect of the Occupational Safety and Health Administration's (OSHA's) 1984 ethylene oxide standard. An in-depth survey of all hospitals in Massachusetts that used ethylene oxide from 1990 through 1992 (96% participation, N = 90) was conducted. Three types of exposure events were modeled with logistic regression: exceeding the 8-hour action level, exceeding the 15-minute excursion limit, and worker exposures during unmeasured accidental releases. Covariates were drawn from data representing an ecologic framework including direct and indirect potential exposure determinants. After adjustment for frequencies of ethylene oxide use and exposure monitoring, a significant inverse relation was observed between exceeding the action level and the use of combined sterilizer-aerators, an engineering control technology developed after the passage of the OSHA standard. Conversely, the use of positive-pressure sterilizers that employ ethylene oxide gas mixtures was strongly related to both exceeding the excursion limit and the occurrence of accidental releases. These findings provide evidence of a positive effect of OSHA's ethylene oxide standard and specific targets for future prevention and control efforts.

Effect of thyroid function on LDL oxidation.

PubMed

Costantini, F; Pierdomenico, S D; De Cesare, D; De Remigis, P; Bucciarelli, T; Bittolo-Bon, G; Cazzolato, G; Nubile, G; Guagnano, M T; Sensi, S; Cuccurullo, F; Mezzetti, A

1998-05-01

In this study, the effect of different levels of thyroid hormone and metabolic activity on low density lipoprotein (LDL) oxidation was investigated. Thus, in 16 patients with hyperthyroidism, 16 with hypothyroidism, and 16 age- and sex-matched healthy normolipidemic control subjects, the native LDL content in lipid peroxides, vitamin E, beta-carotene, and lycopene, as well as the susceptibility of these particles to undergo lipid peroxidation, was assessed. Hyperthyroidism was associated with significantly higher lipid peroxidation, as characterized by a higher native LDL content in lipid peroxides, a lower lag phase, and a higher oxidation rate than in the other two groups. This elevated lipid peroxidation was associated with a lower LDL antioxidant concentration. Interestingly, hypothyroid patients showed an intermediate behavior. In fact, in hypothyroidism, LDL oxidation was significantly lower than in hyperthyroidism but higher than in the control group. Hypothyroidism was also characterized by the highest beta-carotene LDL content, whereas vitamin E was significantly lower than in control subjects. In hyperthyroidism but not in the other two groups, LDL oxidation was strongly influenced by free thyroxine blood content. In fact in this group, the native LDL lipid peroxide content and the lag phase were directly and indirectly, respectively, related to free thyroxine blood levels. On the contrary, in hypothyroidism LDL oxidation was strongly and significantly related to serum lipids. In conclusion, both hypothyroidism and hyperthyroidism are characterized by higher levels of LDL oxidation when compared with normolipidemic control subjects. In hyperthyroid patients, the increased lipid peroxidation was strictly related to free thyroxine levels, whereas in hypothyroidism it was strongly influenced by serum lipids.

Effects of chromium picolinate on oxidative damage in primary piglet hepatocytes.

PubMed

Tan, Gao-Yi; Bi, Jin-Ming; Zhang, Min-Hong; Feng, Jing-Hai; Xie, Peng; Zheng, Shan-Shan

2008-12-01

Chromium picolinate is a popular nutritional supplement whose safety has been questioned because of the potential risk of oxidative DNA damage. To investigate this possibility, a dose-dependent study was performed in piglet hepatocyte cultures in which low (8 microM), medium (200 microM), and high (400 microM) doses of chromium picolinate were tested and compared to untreated controls. After 48 h incubation, there were no significant differences in the levels of intracellular reactive oxygen species, medium lactate dehydrogenase activity, and comet indicators between the three experimental groups and controls (p > 0.05). In the 8 microM-treated group, the intracellular malondialdehyde content was significantly decreased relative to controls (p < 0.05). All of the studied parameters showed a dose-dependent increase that was statistically significant between the low and high doses (p < 0.05). These results suggest that: (1) chromium picolinate may affect the oxidative status of piglet hepatocytes; (2) the appropriate dose (approximately physiological concentration) of chromium picolinate can inhibit lipid peroxidation, and (3) high doses of chromium picolinate have no significant effects on oxidative damage in piglet hepatocytes, but the existing evidence also imply that exposure to a higher dose appears to be unwarranted.

Altered metabolisms of mediators controlling vascular function and enhanced oxidative stress in asymptomatic children with congenital portosystemic venous shunt.

PubMed

Nagasaka, Hironori; Okano, Yoshiyuki; Aizawa, Madoka; Miida, Takashi; Yorifuji, Tohru; Tajima, Go; Sakura, Nobuo; Takatani, Tomozumi; Sanayama, Yoshitami; Sugamoto, Kenji; Mayumi, Mitsufumi; Kobayashi, Kunihiko; Hirano, Kenichi; Takayanagi, Masaki; Tsukahara, Hirokazu

2010-01-01

Children with congenital portosystemic venous shunt (PSVS) are at risk for developing pulmonary hypertension, irrespective of the severity of portal hypertension or liver damage. Altered metabolisms of nitric oxide (NO) and endothelin-1 (ET-1), which are linked with oxidative stress and control vascular tone, might contribute to the vascular disturbance. This study examined 14 children (aged 1-5 years) with congenital PSVS lacking major liver damage and portal hypertension. Serum levels of nitrite/nitrate (NOx) as stable metabolites of NO, and of asymmetric dimethylarginine (ADMA) as an endogenous NO synthase inhibitor were determined, along with the plasma level of ET-1. Oxidative stress, which might affect the production of such mediators, was also examined using specific urinary and blood markers. The NOx levels were significantly lower in affected children than in the age-matched control group, although ET-1 levels were significantly higher than the control levels. In the affected children, the ADMA levels and ADMA/NOx ratios were higher, respectively, by 30% and 130% and showed significant positive correlations with the shunt ratios. Oxidative stress markers, including plasma thiobarbiturate reactive substances and urinary acrolein-lysine and 8-hydroxy-2'-deoxyguanosine, were significantly higher in affected children than in the control group, consistent with them being subjected to enhanced oxidative stress. These results suggest the presence of altered metabolisms of vascular mediators and enhanced oxidative stress in asymptomatic preschool children with congenital PSVS.

Hyperthyroidism stimulates mitochondrial proton leak and ATP turnover in rat hepatocytes but does not change the overall kinetics of substrate oxidation reactions.

PubMed

Harper, M E; Brand, M D

1994-08-01

Thyroid hormones have well-known effects on oxidative phosphorylation, but there is little quantitative information on their important sites of action. We have used top-down elasticity analysis, an extension of metabolic control analysis, to identify the sites of action of thyroid hormones on oxidative phosphorylation in rat hepatocytes. We divided the oxidative phosphorylation system into three blocks of reactions: the substrate oxidation subsystem, the phosphorylating subsystem, and the mitochondrial proton leak subsystem and have identified those blocks of reactions whose kinetics are significantly changed by hyperthyroidism. Our results show significant effects on the kinetics of the proton leak and the phosphorylating subsystems. Quantitative analyses revealed that 43% of the increase in resting respiration rate in hyperthyroid hepatocytes compared with euthyroid hepatocytes was due to differences in the proton leak and 59% was due to differences in the activity of the phosphorylating subsystem. There were no significant effects on the substrate oxidation subsystem. Changes in nonmitochondrial oxygen consumption accounted for -2% of the change in respiration rate. Top-down control analysis revealed that the distribution of control over the rates of mitochondrial oxygen consumption, ATP synthesis and consumption, and proton leak and over mitochondrial membrane potential (delta psi m) was similar in hepatocytes from hyperthyroid and littermate-paired euthyroid controls. The results of this study include the first complete top-down elasticity and control analyses of oxidative phosphorylation in hepatocytes from hyperthyroid rats.

Niacin supplementation increases the number of oxidative type I fibers in skeletal muscle of growing pigs

PubMed Central

2013-01-01

Background A recent study showed that niacin supplementation counteracts the obesity-induced muscle fiber switching from oxidative type I to glycolytic type II and increases the number of type I fibers in skeletal muscle of obese Zucker rats. These effects were likely mediated by the induction of key regulators of fiber transition, PGC-1α and PGC-1β, leading to muscle fiber switching and up-regulation of genes involved in mitochondrial fatty acid import and oxidation, citrate cycle, oxidative phosphorylation, mitochondrial biogenesis. The aim of the present study was to investigate whether niacin supplementation causes type II to type I muscle and changes the metabolic phenotype of skeletal muscles in growing pigs. Results 25 male, 11 wk old crossbred pigs (Danzucht x Pietrain) with an average body weight of 32.8 ± 1.3 (mean ± SD) kg were randomly allocated to two groups of 12 (control group) and 13 pigs (niacin group) which were fed either a control diet or a diet supplemented with 750 mg niacin/kg diet. After 3 wk, the percentage number of type I fibers in three different muscles (M. longissismus dorsi, M. quadriceps femoris, M. gastrocnemius) was greater in the niacin group and the percentage number of type II fibers was lower in the niacin group than in the control group (P < 0.05). The mRNA levels of PGC-1β and genes involved in mitochondrial fatty acid catabolism (CACT, FATP1, OCTN2), citrate cycle (SDHA), oxidative phosphorylation (COX4/1, COX6A1), and thermogenesis (UCP3) in M. longissimus dorsi were greater in the niacin group than in the control group (P < 0.05). Conclusions The study demonstrates that niacin supplementation induces type II to type I muscle fiber switching, and thereby an oxidative metabolic phenotype of skeletal muscle in pigs. Given that oxidative muscle types tend to develop dark, firm and dry pork in response to intense physical activity and/or high psychological stress levels preslaughter, a niacin-induced change in the muscle´s fiber type distribution may influence meat quality of pigs. PMID:24010567

Metabolic responses of Beauveria bassiana to hydrogen peroxide-induced oxidative stress using an LC-MS-based metabolomics approach.

PubMed

Zhang, Chen; Wang, Wei; Lu, Ruili; Jin, Song; Chen, Yihui; Fan, Meizhen; Huang, Bo; Li, Zengzhi; Hu, Fenglin

2016-06-01

The entomopathogenic fungus, Beauveria bassiana, is commonly used as a biological agent for pest control. Environmental and biological factors expose the fungus to oxidative stress; as a result, B. bassiana has adopted a number of anti-oxidant mechanisms. In this study, we investigated metabolites of B. bassiana that are formed in response to oxidative stress from hydrogen peroxide (H2O2) by using a liquid chromatography mass spectrometry (LC-MS) approach. Partial least-squares discriminant analysis (PLS-DA) revealed differences between the control and the H2O2-treated groups. Hierarchical cluster analysis (HCA) showed 18 up-regulated metabolites and 25 down-regulated metabolites in the H2O2-treated fungus. Pathway analysis indicated that B. bassiana may be able to alleviate oxidative stress by enhancing lipid catabolism and glycometabolism, thus decreasing membrane polarity and preventing polar H2O2 or ROS from permeating into fungal cells and protecting cells against oxidative injury. Meanwhile, most of the unsaturated fatty acids that are derived from glycerophospholipids hydrolysis can convert into oxylipins through autoxidation, which can prevent the reactive oxygen of H2O2 from attacking important macromolecules of the fungus. Results showed also that H2O2 treatment can enhance mycotoxins production which implies that oxidative stress may be able to increase the virulence of the fungus. In comparison to the control group, citric acid and UDP-N-acetylglucosamine were down-regulated, which suggested that metabolic flux was occurring to the TCA cycle and enhancing carbohydrate metabolism. The findings from this study will contribute to the understanding of how the molecular mechanisms of fungus respond to environmental and biological stress factors as well as how the manipulation of such metabolisms may lead to selection of more effective fungal strains for pest control. Copyright © 2016 Elsevier Inc. All rights reserved.

Lipid Peroxidation and Antioxidant Status in Patients with Medullary Thyroid Carcinoma: A Case-Control Study.

PubMed

Hosseini-Zijoud, Seyed-Mostafa; Ebadi, Seyed Alireza; Goodarzi, Mohammad Taghi; Hedayati, Mehdi; Abbasalipourkabir, Roghayeh; Mahjoob, Mohammad Parsa; Poorolajal, Jalal; Zicker, Fabio; Sheikh, Nasrin

2016-02-01

Oxidative stress or oxidant/antioxidant imbalance has a crucial role in the pathogenesis of some diseases like cancer. Medullary thyroid carcinoma (MTC) originates in the thyroid parafollicular cells and includes 3-4% of the malignant neoplasms that have an effect on this gland. The aetiology of MTC has not been clarified. However, oxidative stress may be one of the factors involved. The aim of the current study was to evaluate the antioxidant enzyme activity of catalase (CAT), Glutathione (GSH), total antioxidant capacity (TAC) and the levels of the lipid peroxidation product malondialdehyde (MDA) in blood samples of MTC patients as compared to healthy controls. A case-control study was designed enrolling patients with confirmed MTC diagnosis and age-and sex group matched healthy volunteers referred to the clinic of the Research Institute for Endocrine Sciences, Tehran, Iran from April 2013 to July 2015. Fasting blood samples were taken for study. Catalase, GSH, MDA and TAC levels were measured by colorimetry using commercial kits (ZellBio GmbH, Germany). Data were analysed using SPSS 17 software, comparing mean±SD through t-test and difference between proportions through chi-square. No statistical difference was observed in the demographic characteristic between cases and controls. The final MTC group included 40 males and 45 females with a mean age of 30±12.9 year, and the control group 40 males and 47 females, with a mean age of 31.2±12.3 year. Anthropometric parameters, dietary and thyroid hormones levels (T3, T4 and TSH) were similar. Serum TAC (p=0.015), GSH (p=0.029) and CAT (p<0.001) levels were found to be significantly lower in the MTC patients, while serum MDA levels were significantly higher in MTC patients than controls (p<0.001). These preliminary findings suggest that oxidant/antioxidant imbalance may be associated with or possibly indicate an increased risk to medullary thyroid carcinoma. Further studies are needed to explore these findings.

Controlling the physics and chemistry of binary and ternary praseodymium and cerium oxide systems.

PubMed

Niu, Gang; Zoellner, Marvin Hartwig; Schroeder, Thomas; Schaefer, Andreas; Jhang, Jin-Hao; Zielasek, Volkmar; Bäumer, Marcus; Wilkens, Henrik; Wollschläger, Joachim; Olbrich, Reinhard; Lammers, Christian; Reichling, Michael

2015-10-14

Rare earth praseodymium and cerium oxides have attracted intense research interest in the last few decades, due to their intriguing chemical and physical characteristics. An understanding of the correlation between structure and properties, in particular the surface chemistry, is urgently required for their application in microelectronics, catalysis, optics and other fields. Such an understanding is, however, hampered by the complexity of rare earth oxide materials and experimental methods for their characterisation. Here, we report recent progress in studying high-quality, single crystalline, praseodymium and cerium oxide films as well as ternary alloys grown on Si(111) substrates. Using these well-defined systems and based on a systematic multi-technique surface science approach, the corresponding physical and chemical properties, such as the surface structure, the surface morphology, the bulk-surface interaction and the oxygen storage/release capability, are explored in detail. We show that specifically the crystalline structure and the oxygen stoichiometry of the oxide thin films can be well controlled by the film preparation method. This work leads to a comprehensive understanding of the properties of rare earth oxides and highlights the applications of these versatile materials. Furthermore, methanol adsorption studies are performed on binary and ternary rare earth oxide thin films, demonstrating the feasibility of employing such systems for model catalytic studies. Specifically for ceria systems, we find considerable stability against normal environmental conditions so that they can be considered as a "materials bridge" between surface science models and real catalysts.

Total oxidant status, total antioxidant capacity and ischemia modified albumin levels in children with celiac disease.

PubMed

Sayar, Ersin; Özdem, Sebahat; Uzun, Gülbahar; İşlek, Ali; Yılmaz, Aygen; Artan, Reha

2015-01-01

In our study, we aimed to investigate ischemia modified albumin (IMA) as an oxidative stress marker, as well as other oxidant and antioxidant markers that have not been evaluated in children with celiac disease. A total of 37 pediatric patients who were diagnosed with celiac disease (CD) and 29 healthy children were enrolled in this prospective study. We evaluated the IMA, total oxidant status, total antioxidant capacity, sulfhydryl, and advanced oxidation protein products in all of the subjects. We also compared the levels at the time of the diagnosis, and following a gluten-free diet (GFD) in the children with CD. While the IMA and the other oxidant marker levels were significantly higher in the patient group compared to the control group, the antioxidant marker levels were found to be significantly lower in the patient group, compared to the control group. We also determined that the tissue transglutaminase IgA showed a highly positive correlation, and that the IMA showed a moderately positive correlation with the Marsh-Oberhuber histopathological stage. Additionally, the IMA and other oxidant marker levels were significantly lower, while the antioxidant marker levels were significantly higher after the GFD, compared to the pre-diet period. We detected that oxidative stress played a role in the pathogenesis of CD, and that this could be evaluated using oxidative stress markers, which would regress after the GFD. We also detected that IMA is a marker that shows a correlation with the histopathological stage, and may be used in the diagnosis.

Systemic Inflammation after Third Molar Removal: A Case-Control Study.

PubMed

Graziani, F; D'Aiuto, F; Gennai, S; Petrini, M; Nisi, M; Cirigliano, N; Landini, L; Bruno, R M; Taddei, S; Ghiadoni, L

2017-12-01

Third molar extraction is one of the most frequent interventions in dentistry. Nevertheless, there is scarce evidence on the host response of individuals with impacted or semi-impacted third molars and the possible effects of surgical removal. A case-control study of 40 patients was designed to evaluate 1) the differences in biomarkers of systemic inflammation, vascular function, and metabolism (high-sensitive C-reactive protein, lipids, fibrinogen, oxidative stress, and endothelial function analysis) and 2) the acute and short-term effects of surgical removal in patients with bilateral impacted or semi-impacted third molars compared to controls with no third molars. Patients undergoing third molar extraction exhibited greater levels of systemic inflammation, oxidative stress, and triglycerides than controls. Raised white blood cell counts as well as peaks of serum levels of C-reactive protein and fibrinogen were noticed in the first postoperative week. Three months after the extraction, all markers returned to baseline values. Malondialdehyde, an indicator of oxidative stress indicator, was significantly reduced after third molar removal. Semi-impacted or impacted third molars are associated with higher systemic inflammation, and their removal may represent a useful human model to study acute inflammation and determine beneficial systemic effects ( ClinicalTrials.gov NCT03048175).

Oxidative stress and neurological disorders in relation to blood lead levels in children.

PubMed

Ahamed, M; Fareed, Mohd; Kumar, A; Siddiqui, W A; Siddiqui, M K J

2008-01-01

Oxidative stress plays a pivotal role in the pathogenesis of neurological disorders. Free radical generation appears to be the mode of lead toxicity. We evaluated the effects of blood lead levels on oxidative stress parameters in children suffering from neurological disorders. Thirty children (aged 3-12 years) with neurological disorders (cerebral palsy [n = 12], seizures [n = 11], and encephalopathy [n = 7]) were recruited in the study group. Sixty healthy children (aged 3-12 years) from similar socio-economic environments and not suffering from any chronic disease were taken as the controls. Blood lead levels and oxidant/antioxidant status were determined. Mean blood lead level was significantly higher while delta-aminolevulinic acid dehydratase (delta-ALAD) activity, a biomarker for lead exposure, was significantly lower in the study group as compared to the control group (P < 0.05 for each). Malondialdehyde (MDA) levels, an end-product of lipid peroxidation, were significantly higher while the antioxidant glutathione (GSH) levels were significantly lower in the study group as compared to the control group (P < 0.05 for each). Activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) were significantly higher in the study group than those of the control group (P < 0.05 for each). There were significant negative correlations of blood lead levels with delta-ALAD (r = -0.35; P < 0.05) and GSH (r = -0.31; P < 0.05), and positive correlations with MDA (r = 0.37; P < 0.05), SOD (r = 0.53; P < 0.05), and CAT (r = 0.31; P < 0.05). In turn, delta-ALAD had significant negative correlations with MDA (r = -0.29; P < 0.05), SOD (r = -0.28; P < 0.05) and CAT (r = -0.34; P < 0.05), but positive correlation with GSH (r = 0.32; P < 0.05). Although a causal pathway can not be determined from the present study, our findings indicate lead-induced oxidative stress in blood of children with neurological disorders. Lead-induced oxidative stress as an underlying mechanism for neurological diseases in children warranted further investigation.

Size and space controlled hexagonal arrays of superparamagnetic iron oxide nanodots: magnetic studies and application

PubMed Central

Ghoshal, Tandra; Maity, Tuhin; Senthamaraikannan, Ramsankar; Shaw, Matthew T.; Carolan, Patrick; Holmes, Justin D.; Roy, Saibal; Morris, Michael A.

2013-01-01

Highly dense hexagonally arranged iron oxide nanodots array were fabricated using PS-b-PEO self-assembled patterns. The copolymer molecular weight, composition and choice of annealing solvent/s allows dimensional and structural control of the nanopatterns at large scale. A mechanism is proposed to create scaffolds through degradation and/or modification of cylindrical domains. A methodology based on selective metal ion inclusion and subsequent processing was used to create iron oxide nanodots array. The nanodots have uniform size and shape and their placement mimics the original self-assembled nanopatterns. For the first time these precisely defined and size selective systems of ordered nanodots allow careful investigation of magnetic properties in dimensions from 50 nm to 10 nm, which delineate the nanodots are superparamagnetic, well-isolated and size monodispersed. This diameter/spacing controlled iron oxide nanodots systems were demonstrated as a resistant mask over silicon to fabricate densely packed, identical ordered, high aspect ratio silicon nanopillars and nanowire features. PMID:24072037

Serum oxidant and antioxidant levels in diesel exposed toll collectors.

PubMed

Arbak, Peri; Yavuz, Ozlem; Bukan, Neslihan; Balbay, Oner; Ulger, Füsun; Annakkaya, Ali Nihat

2004-07-01

It has been suggested that exposure to diesel exhaust may lead to adverse effects due to the generation of oxidants. To evaluate the end products of oxidative stress in DE exposure, toll collectors who are considered a high risk group in regard to occupational toxins were compared to controls who had office-based occupations in the same company in this cross sectional study. A total of 38 toll collectors constituted the study group. All subjects were male. The toll collectors and 29 controls were similar regarding age, smoking status and duration of work. All subjects underwent a clinical examination and an interviewer-administrated questionnaire regarding respiratory symptoms, past medical and occupational history, and pulmonary function tests were performed in all subjects. Serum malondialdehyde (MDA), nitrite+nitrate and vitamin E levels were measured. Toll collectors showed higher serum MDA (5.76 +/- 2.15 micromol/L vs. 3.07 +/- 0.76 micromol/L, p=0.0001) and nitrite+nitrate levels (96.50 +/- 45.54 micromol/L vs. 19.32 +/- 11.77 micromol/L, p=0.0001) than controls. Vitamin E levels were similar in toll collectors and controls (10.57 +/- 3.44 mg/L and 9.72 +/- 2.44 mg/L, respectively, p=0.267). There was no difference between groups in terms of the findings of clinical examinations and respiratory symptoms. In pulmonary function parameters, only peak expiratory flow (PEF) in toll collectors was significantly lower than that of controls (88.9% predicted and 104.2% predicted, respectively, p=0.012). In conclusion, we suggest that serum MDA and nitrite+nitrate levels may be used as biological markers of oxidative stress related to DE exposure, but prospective controlled clinical studies are necessary to clarify the possible association between concentrations of MDA and nitrite+nitrate and pulmonary diseases related to DE exposure.

Insulin resistance in non-obese women with polycystic ovary syndrome: relation to byproducts of oxidative stress.

PubMed

Macut, D; Simic, T; Lissounov, A; Pljesa-Ercegovac, M; Bozic, I; Djukic, T; Bjekic-Macut, J; Matic, M; Petakov, M; Suvakov, S; Damjanovic, S; Savic-Radojevic, A

2011-07-01

To get more insight into molecular mechanisms underlying oxidative stress and its link with insulin resistance, oxidative stress parameters, as well as, antioxidant enzyme activities were studied in young, non-obese women with polycystic ovary syndrome (PCOS). Study was performed in 34 PCOS women and 23 age and body mass index (BMI)-matched healthy controls. Plasma nitrotyrosine and malondialdehyde (MDA), representative byproducts of protein and lipid oxidative damage, were determined by enzyme immunoassay. Antioxidant enzyme activities, superoxide dismutase (SOD) and glutathione peroxidase (GPX) were studied spectrophotometrically. Insulin resistance was calculated using homeostasis assessment model (HOMA-IR). Plasma nitrotyrosine and MDA were increased, but only nitrotyrosine was significantly higher (p < 0.05) in PCOS women compared to controls. Uric acid (surrogate marker of × antine oxidase) was also significantly elevated in PCOS (p < 0.05). Both plasma SOD and GPX activity showed no statistically significant difference between PCOS and controls. Indices of insulin resistance (insulin and HOMAIR) were significantly higher in PCOS group and positively correlated with level of MDA (r = 0.397 and r = 0.523, respectively; p < 0.05) as well as GPX activity (r = 0.531 and r = 0.358, respectively; p < 0.05). Our results indicate that insulin resistance could be responsible for the existence of subtle form of oxidative stress in young, nonobese PCOS women. Hence, presence of insulin resistance, hyperinsulinemia and oxidative damage are likely to accelerate slow development of cardiovascular disease in PCOS. © J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York.

Oxidative stress status in patients with melasma.

PubMed

Seçkin, Havva Yıldız; Kalkan, Göknur; Baş, Yalçın; Akbaş, Ali; Önder, Yalçın; Özyurt, Hüseyin; Sahin, Mehmet

2014-09-01

Melasma is an acquired skin disease characterized clinically by development of gray-brown macules or patches. The lesions have geographic borders and most often seen on face and less frequently on the neck and forearms. Pathogenesis has not been completely understood yet. Although the disease constitutes a very disturbing cosmetic problem, it has not obtained an efficient treatment. There were not any studies in the literature that evaluates the role of oxidative stress in melasma. The evaluation of the role of oxidative stress in melasma. Fifty melasma patients and 50 healthy volunteers were included in the study. The diagnosis was made clinically and the patients were evaluated by Melasma Area Severity Index. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) enzyme activities and malondialdehyde, nitric oxide, protein carbonyl levels were measured both in the melasma group and the control group. SOD and GSH-Px enzyme activities were significantly higher in the patient group in comparison with the control group (p < 0.001). Protein carbonyl levels were significantly lower in the patient group (p < 0.001). The results show that the balance between oxidant and anti-oxidants was disrupted and the oxidative stress increased in melasma. These results improve the understanding of etiology-pathogenesis of the disease and its treatment.

40 CFR 52.1781 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Sulfur oxides and particulate matter. 52.1781 Section 52.1781 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Carolina § 52.1781 Control strategy: Sulfur oxides and particulate matter. (a) The plan's control strategy...

40 CFR 52.1781 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Sulfur oxides and particulate matter. 52.1781 Section 52.1781 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Carolina § 52.1781 Control strategy: Sulfur oxides and particulate matter. (a) The plan's control strategy...

Effectiveness of nitrous oxide for postpartum perineal repair: a randomised controlled trial.

PubMed

Berlit, Sebastian; Tuschy, Benjamin; Brade, Joachim; Mayer, Jade; Kehl, Sven; Sütterlin, Marc

2013-10-01

To compare the effectiveness of self-administered 50% nitrous oxide and conventional infiltrative anaesthesia with 1% prilocaine hydrochloride in postpartum perineal repair. A total of 100 women were prospectively enrolled and randomised to receive either infiltrative anaesthesia or a self-administered nitrous oxide mixture (Livopan(©)) for pain relief during postpartum perineal suturing. Besides data concerning anaesthesia, characteristics of patients and labour were documented for statistical analysis. Pain experienced during perineal repair was assessed using the short form of the McGill Pain Questionnaire (SF-MPQ). Forty-eight women received nitrous oxide and 52 underwent perineal suturing after infiltrative anaesthesia. There were no statistically significant differences regarding maternal age, body mass index (BMI), duration of pregnancy and suturing time between the groups. The most frequent birth injury was second-degree perineal laceration in the study group [22/48; 46%] and episiotomy in the control group [18/52; 35%]. Pain experienced during genital tract suturing and patients' satisfaction showed no statistically significant differences between the groups. Thirty-seven women in the study group and 47 in the control group were satisfied with the anaesthesia during perineal repair and would recommend it to other parturients [37/48, 77% vs. 47/52, 90%; p=0.0699). Nitrous oxide self-administration during genital tract suturing after vaginal childbirth is a satisfactory and effective alternative to infiltrative anaesthesia. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Increased oxidative stress in infants exposed to passive smoking.

PubMed

Aycicek, Ali; Erel, Ozcan; Kocyigit, Abdurrahim

2005-12-01

The purpose of this study was to assess the effect of passive cigarette smoking on the oxidative and anti-oxidative status of plasma in infants. Eighty-four infants aged 6-28 weeks were divided into two groups: the study group included infants who had been exposed to passive smoking via at least five cigarettes per day for at least the past 6 weeks at home, while the control group included infants who had never been exposed to passive smoking. The antioxidative status of plasma was assessed by the measurement of individual antioxidant components: vitamin C, albumin, bilirubin, uric acid, thiol contents and total antioxidant capacity (TAC 1 and TAC 2). Oxidative status was assessed by the determination of total peroxide levels and the oxidative stress index (OSI 1 and OSI 2). Plasma vitamin C, thiol concentration and TAC 1 and TAC 2 levels were significantly lower, whereas plasma total peroxide levels and OSI 1 and OSI 2 were significantly higher, in passive smoking infants than in the controls (P<0.01). We conclude that passive smoking has a negative impact on numerous parts of the antioxidant defence system in infants, and exposes them to potent oxidative stress.

Opuntia ficus indica (nopal) attenuates hepatic steatosis and oxidative stress in obese Zucker (fa/fa) rats.

PubMed

Morán-Ramos, Sofía; Avila-Nava, Azalia; Tovar, Armando R; Pedraza-Chaverri, José; López-Romero, Patricia; Torres, Nimbe

2012-11-01

Nonalcoholic fatty liver disease (NAFLD) is associated with multiple factors such as obesity, insulin resistance, and oxidative stress. Nopal, a cactus plant widely consumed in the Mexican diet, is considered a functional food because of its antioxidant activity and ability to improve biomarkers of metabolic syndrome. The aim of this study was to assess the effect of nopal consumption on the development of hepatic steatosis and hepatic oxidative stress and on the regulation of genes involved in hepatic lipid metabolism. Obese Zucker (fa/fa) rats were fed a control diet or a diet containing 4% nopal for 7 wk. Rats fed the nopal-containing diet had ∼50% lower hepatic TG than the control group as well as a reduction in hepatomegaly and biomarkers of hepatocyte injury such as alanine and aspartate aminotransferases. Attenuation of hepatic steatosis by nopal consumption was accompanied by a higher serum concentration of adiponectin and a greater abundance of mRNA for genes involved in lipid oxidation and lipid export and production of carnitine palmitoyltransferase-1 and microsomal TG transfer proteins in liver. Hepatic reactive oxygen species and lipid peroxidation biomarkers were significantly lower in rats fed nopal compared with the control rats. Furthermore, rats fed the nopal diet had a lower postprandial serum insulin concentration and a greater liver phosphorylated protein kinase B (pAKT):AKT ratio in the postprandial state. This study suggests that nopal consumption attenuates hepatic steatosis by increasing fatty acid oxidation and VLDL synthesis, decreasing oxidative stress, and improving liver insulin signaling in obese Zucker (fa/fa) rats.

Treatment of CELSS and PCELSS waste to produce nutrients for plant growth. [Controlled Ecological Life Support Systems and Partially Controlled Ecological Life Support Systems

NASA Technical Reports Server (NTRS)

Modell, M.; Meissner, H.; Karel, M.; Carden, J.; Lewis, S.

1981-01-01

The research program entitled 'Development of a Prototype Experiment for Treating CELSS (Controlled Ecological Life Support Systems) and PCELSS (Partially Controlled Ecological Life Support Systems) Wastes to Produce Nutrients for Plant Growth' consists of two phases: (1) the development of the neccessary facilities, chemical methodologies and models for meaningful experimentation, and (2) the application of what methods and devices are developed to the interfacing of waste oxidation with plant growth. Homogeneous samples of freeze-dried human feces and urine have been prepared to ensure comparability of test results between CELSS waste treatment research groups. A model of PCELSS food processing wastes has been developed, and an automated gas chromatographic system to analyze oxidizer effluents was designed and brought to operational status. Attention is given the component configuration of the wet oxidation system used by the studies.

Elemental mercury oxidation in an electrostatic precipitator enhanced with in situ soft X-ray irradiation.

PubMed

Jing, He; Wang, Xiaofei; Wang, Wei-Ning; Biswas, Pratim

2015-04-01

Corona discharge based techniques are promising approaches for oxidizing elemental mercury (Hg0) in flue gas from coal combustion. In this study, in-situ soft X-rays were coupled to a DC (direct current) corona-based electrostatic precipitator (ESP). The soft X-rays significantly enhanced Hg0 oxidation, due to generation of electrons from photoionization of gas molecules and the ESP electrodes. This coupling technique worked better in the positive corona discharge mode because more electrons were in the high energy region near the electrode. Detailed mechanisms of Hg0 oxidation are proposed and discussed based on ozone generation measurements and Hg0 oxidation behavior observations in single gas environments (O2, N2, and CO2). The effect of O2 concentration in flue gas, as well as the effects of particles (SiO2, TiO2, and KI) was also evaluated. In addition, the performance of a soft X-rays coupled ESP in Hg0 oxidations was investigated in a lab-scale coal combustion system. With the ESP voltage at +10 kV, soft X-ray enhancement, and KI addition, mercury oxidation was maximized. Mercury is a significant-impact atmospheric pollutant due to its toxicity. Coal-fired power plants are the primary emission sources of anthropogenic releases of mercury; hence, mercury emission control from coal-fired power plant is important. This study provides an alternative mercury control technology for coal-fired power plants. The proposed electrostatic precipitator with in situ soft X-rays has high efficiency on elemental mercury conversion. Effects of flue gas conditions (gas compositions, particles, etc.) on performance of this technology were also evaluated, which provided guidance on the application of the technology for coal-fired power plant mercury control.

Implications of chronic daily anti-oxidant administration on the inflammatory response to intracortical microelectrodes

NASA Astrophysics Data System (ADS)

Potter-Baker, Kelsey A.; Stewart, Wade G.; Tomaszewski, William H.; Wong, Chun T.; Meador, William D.; Ziats, Nicholas P.; Capadona, Jeffrey R.

2015-08-01

Objective. Oxidative stress events have been implicated to occur and facilitate multiple failure modes of intracortical microelectrodes. The goal of the present study was to evaluate the ability of a sustained concentration of an anti-oxidant and to reduce oxidative stress-mediated neurodegeneration for the application of intracortical microelectrodes. Approach. Non-functional microelectrodes were implanted into the cortex of male Sprague Dawley rats for up to sixteen weeks. Half of the animals received a daily intraperitoneal injection of the natural anti-oxidant resveratrol, at 30 mg kg-1. The study was designed to investigate the biodistribution of the resveratrol, and the effects on neuroinflammation/neuroprotection following device implantation. Main results. Daily maintenance of a sustained range of resveratrol throughout the implantation period resulted in fewer degenerating neurons in comparison to control animals at both two and sixteen weeks post implantation. Initial and chronic improvements in neuronal viability in resveratrol-dosed animals were correlated with significant reductions in local superoxide anion accumulation around the implanted device at two weeks after implantation. Controls, receiving only saline injections, were also found to have reduced amounts of accumulated superoxide anion locally and less neurodegeneration than controls at sixteen weeks post-implantation. Despite observed benefits, thread-like adhesions were found between the liver and diaphragm in resveratrol-dosed animals. Significance. Overall, our chronic daily anti-oxidant dosing scheme resulted in improvements in neuronal viability surrounding implanted microelectrodes, which could result in improved device performance. However, due to the discovery of thread-like adhesions, further work is still required to optimize a chronic anti-oxidant dosing regime for the application of intracortical microelectrodes.

40 CFR 52.1877 - Control strategy: Photochemical oxidants (hydrocarbons).

Code of Federal Regulations, 2011 CFR

2011-07-01

... oxidants (hydrocarbons). 52.1877 Section 52.1877 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY....1877 Control strategy: Photochemical oxidants (hydrocarbons). (a) The requirements of Subpart G of this... national standard for photochemical oxidants (hydrocarbons) in the Metropolitan Cincinnati interstate...

40 CFR 52.1877 - Control strategy: Photochemical oxidants (hydrocarbons).

Code of Federal Regulations, 2010 CFR

2010-07-01

... oxidants (hydrocarbons). 52.1877 Section 52.1877 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY....1877 Control strategy: Photochemical oxidants (hydrocarbons). (a) The requirements of Subpart G of this... national standard for photochemical oxidants (hydrocarbons) in the Metropolitan Cincinnati interstate...

Interactions between nitrogen cycling and methane oxidation in the pelagic waters of the Gulf of Mexico.

NASA Astrophysics Data System (ADS)

Joye, S. B.; Weber, S.; Battles, J.; Montoya, J. P.

2014-12-01

Methane is an important greenhouse gas that plays a critical role in climate variation. Although a variety of marine methane sources and sinks have been identified, key aspects of the fate of methane in the ocean remain poorly constrained. At cold seeps in the Gulf of Mexico and elsewhere, methane is introduced into the overlying water column via fluid escape from the seabed. We quantified the fate of methane in the water column overlying seafloor cold seeps, in a brine basin, and at several control sites. Our goals were to determine the factors that regulated methane consumption and assimilation and to explore how these controlling factors varied among and between sites. In particular, we examined the impact of nitrogen availability on methane oxidation and studied the ability of methane oxidizing bacteria to fix molecular nitrogen. Methane oxidation rates were highest in the methane rich bottom waters of natural hydrocabron seeps. At these sites, inorganic nitrogen addition stimulated methane oxidation in laboratory experiments. In vitro shipboard experiments revealed that rates of methane oxidation and nitrogen fixation were correlated strongly, suggesting that nitrogen fixation may have been mediated by methanotrophic bacteria. The highest rates of methane oxidation and nitrogen fixation were observed in the deepwater above at natural hydrocarbon seeps. Rates of methane oxidation were substantial along the chemocline of a brine basin but in these ammonium-rich brines, addition of inorganic nitrogen had little impact on methane oxidation suggesting that methanotrophy in these waters were not nitrogen limited. Control sites exhibited the lowest methane concentrations and methane oxidation rates but even these waters exhibited substantial potential for methane oxidation when methane and inorganic nitrogen concentrations were increased. Together, these data suggest that the availability of inorganic nitrogen plays a critical role in regulating methane oxidation in pelagic ocean waters. Some methanotrophs may obtain a competitive advantage in nitrogen-limited oceanic environments by fixing molecular nitrogen. The importance of such "methano-diazotrophy" on a global scale warrants further investigation.

Investigation of Zircaloy-2 oxidation model for SFP accident analysis

NASA Astrophysics Data System (ADS)

Nemoto, Yoshiyuki; Kaji, Yoshiyuki; Ogawa, Chihiro; Kondo, Keietsu; Nakashima, Kazuo; Kanazawa, Toru; Tojo, Masayuki

2017-05-01

The authors previously conducted thermogravimetric analyses on Zircaloy-2 in air. By using the thermogravimetric data, an oxidation model was constructed in this study so that it can be applied for the modeling of cladding degradation in spent fuel pool (SFP) severe accident condition. For its validation, oxidation tests of long cladding tube were conducted, and computational fluid dynamics analyses using the constructed oxidation model were proceeded to simulate the experiments. In the oxidation tests, high temperature thermal gradient along the cladding axis was applied and air flow rates in testing chamber were controlled to simulate hypothetical SFP accidents. The analytical outputs successfully reproduced the growth of oxide film and porous oxide layer on the claddings in oxidation tests, and validity of the oxidation model was proved. Influence of air flow rate for the oxidation behavior was thought negligible in the conditions investigated in this study.

Scattering attributes of one-dimensional semiconducting oxide nanomaterials individually probed for varying light-matter interaction angles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Daniel S.; Singh, Manpreet; Zhou, Hebing

2015-10-12

We report the characteristic optical responses of one-dimensional semiconducting oxide nanomaterials by examining the individual nanorods (NRs) of ZnO, SnO{sub 2}, indium tin oxide, and zinc tin oxide under precisely controlled, light-matter interaction geometry. Scattering signals from a large set of NRs of the different types are evaluated spatially along the NR length while varying the NR tilt angle, incident light polarization, and analyzer rotation. Subsequently, we identify material-indiscriminate, NR tilt angle- and incident polarization-dependent scattering behaviors exhibiting continuous, intermittent, and discrete responses. The insight gained from this study can advance our fundamental understanding of the optical behaviors of themore » technologically useful nanomaterials and, at the same time, promote the development of highly miniaturized, photonic and bio-optical devices utilizing the spatially controllable, optical responses of the individual semiconducting oxide NRs.« less

Fundamentals of Passive Oxidation In SiC and Si3N4

NASA Technical Reports Server (NTRS)

Thomas-Ogbuji, Linus U.

1998-01-01

The very slow oxidation kinetics of silicon carbide and silicon nitride, which derive from their adherent and passivating oxide films, has been explored at length in a broad series of studies utilizing thermogravimetric analysis, electron and optical micrography, energy dispersive spectrometry, x-ray diffractometry, micro-analytical depth profiling, etc. Some interesting microstructural phenomena accompanying the process of oxidation in the two materials will be presented. In Si3N4 the oxide is stratified, with an SiO2 topscale (which is relatively impervious to O2)underlain by a coherent subscale of silicon oxynitride which is even less permeable to O2- Such "defence in depth" endows Si3N4 with what is perhaps the highest oxidation resistance of any material, and results in a unique set of oxidation processes. In SiC the oxidation reactions are much simpler, yet new issues still emerge; for instance, studies involving controlled devitrification of the amorphous silica scale confirmed that the oxidation rate of SiC drops by more than an order of magnitude when the oxide scale fully crystallizes.

Effect of the tocotrienol-rich fraction on the lifespan and oxidative biomarkers in Caenorhabditis elegans under oxidative stress

PubMed Central

Aan, Goon Jo; Zainudin, Mohd Shahril Aszrin; Karim, Noralisa Abdul; Ngah, Wan Zurinah Wan

2013-01-01

OBJECTIVE: This study was performed to determine the effect of the tocotrienol-rich fraction on the lifespan and oxidative status of C. elegans under oxidative stress. METHOD: Lifespan was determined by counting the number of surviving nematodes daily under a dissecting microscope after treatment with hydrogen peroxide and the tocotrienol-rich fraction. The evaluated oxidative markers included lipofuscin, which was measured using a fluorescent microscope, and protein carbonyl and 8-hydroxy-2′-deoxyguanosine, which were measured using commercially available kits. RESULTS: Hydrogen peroxide-induced oxidative stress significantly decreased the mean lifespan of C. elegans, which was restored to that of the control by the tocotrienol-rich fraction when administered before or both before and after the hydrogen peroxide. The accumulation of the age marker lipofuscin, which increased with hydrogen peroxide exposure, was decreased with upon treatment with the tocotrienol-rich fraction (p<0.05). The level of 8-hydroxy-2′-deoxyguanosine significantly increased in the hydrogen peroxide-induced group relative to the control. Treatment with the tocotrienol-rich fraction before or after hydrogen peroxide induction also increased the level of 8-hydroxy-2′-deoxyguanosine relative to the control. However, neither hydrogen peroxide nor the tocotrienol-rich fraction treatment affected the protein carbonyl content of the nematodes. CONCLUSION: The tocotrienol-rich fraction restored the lifespan of oxidative stress-induced C. elegans and reduced the accumulation of lipofuscin but did not affect protein damage. In addition, DNA oxidation was increased. PMID:23778402

Effect of the tocotrienol-rich fraction on the lifespan and oxidative biomarkers in Caenorhabditis elegans under oxidative stress.

PubMed

Aan, Goon Jo; Zainudin, Mohd Shahril Aszrin; Karim, Noralisa Abdul; Ngah, Wan Zurinah Wan

2013-05-01

This study was performed to determine the effect of the tocotrienol-rich fraction on the lifespan and oxidative status of C. elegans under oxidative stress. Lifespan was determined by counting the number of surviving nematodes daily under a dissecting microscope after treatment with hydrogen peroxide and the tocotrienol-rich fraction. The evaluated oxidative markers included lipofuscin, which was measured using a fluorescent microscope, and protein carbonyl and 8-hydroxy-2'-deoxyguanosine, which were measured using commercially available kits. Hydrogen peroxide-induced oxidative stress significantly decreased the mean lifespan of C. elegans, which was restored to that of the control by the tocotrienol-rich fraction when administered before or both before and after the hydrogen peroxide. The accumulation of the age marker lipofuscin, which increased with hydrogen peroxide exposure, was decreased with upon treatment with the tocotrienol-rich fraction (p<0.05). The level of 8-hydroxy-2'-deoxyguanosine significantly increased in the hydrogen peroxide-induced group relative to the control. Treatment with the tocotrienol-rich fraction before or after hydrogen peroxide induction also increased the level of 8-hydroxy-2'-deoxyguanosine relative to the control. However, neither hydrogen peroxide nor the tocotrienol-rich fraction treatment affected the protein carbonyl content of the nematodes. The tocotrienol-rich fraction restored the lifespan of oxidative stress-induced C. elegans and reduced the accumulation of lipofuscin but did not affect protein damage. In addition, DNA oxidation was increased.

Oxidative stress in the blood of farm workers following intensive pesticide exposure.

PubMed

Ogut, Serdal; Gultekin, Fatih; Kisioglu, A Nesimi; Kucukoner, Erdoğan

2011-10-01

The aim of this study was to evaluate oxidative stress in workers who formulate organophosphate, synthetic pyrethroid and carbamate pesticides. In this survey, blood erythrocytes from a group of 94 pesticide-formulating workers (at least 5-years experience in pest-control in apple and cherry production) and 45 control subjects were examined for oxidative stress parameters. The control group was composed of 45 healthy people living in the same region with no exposure to pesticides. Lipid peroxidation level, catalase, superoxide dismutase and glutathione peroxidase activities in erythrocytes were analysed as biomarkers of oxidative stress. In addition, the acetylcholinesterase activity was measured as a biomarker of toxicity. Results indicated that chronic exposure to organophosphate, synthetic pyrethroid and carbamate pesticides were associated with increased activities of catalase, SOD and lipid peroxidation in erythrocytes (p < 0.05). Acetylcholinesterase activity did not show any significant differences between the two groups (p > 0.05). It is concluded that human chronic exposure to pesticides may result in stimulated antioxidant enzymes.

Increased incidence of micronuclei assessed with the micronucleus assay and the fluorescence in situ hybridization (FISH) technique in peripheral blood lymphocytes of nurses exposed to nitrous oxide.

PubMed

Lewińska, D; Stepnik, M; Krajewski, W; Arkusz, J; Stańczyk, M; Wrońska-Nofer, T

2005-03-07

It has been postulated that exposure to nitrous oxide and halogenated anaesthetics is associated with various adverse health effects such as neurological and reproductive abnormalities or impairment of hepatic functions. In spite of the quite well known genotoxic effects of exposure to nitrous oxide in vivo, the mechanisms of these effects are still not clear. The aim of this study was to assess the frequency of micronuclei and to identify the type of chromosomal damage (clastogenic or aneugenic) in peripheral blood lymphocytes of operating-room nurses exposed to nitrous oxide. The study group comprised 46 women working at departments where the concentration of nitrous oxide ranged from 14 to 2308 mg/m3. The control population was composed of 28 women employed in the same hospitals but in non-surgical departments. The clastogenic/aneugenic effect of nitrous oxide was evaluated in lymphocytes using the standard micronucleus (MN) assay in combination with the fluorescence in situ hybridization (FISH) technique with pancentromeric probes. The results show a significant increase of the MN frequency in lymphocytes of exposed nurses compared with the control group (4.36+/-2.23 versus 9.02+/-4.67). The multiple regression analysis revealed a statistically significant relationship (p=0.0009) between MN frequency and exposure status, indicating that the level of exposure was the main factor affecting chromosomal damage. As assessed by FISH analysis, the overall frequencies of centromere-positive MN in the control and exposed groups were 43 and 49%, respectively. The increase observed in the exposed group may suggest a slight, statistically insignificant pro-aneugenic effect of exposure to nitrous oxide.

The impact of levothyroxine sodium treatment on oxidative stress in Hashimoto's thyroiditis.

PubMed

Ates, Ihsan; Altay, Mustafa; Yilmaz, Fatma Meric; Topcuoglu, Canan; Yilmaz, Nisbet; Berker, Dilek; Guler, Serdar

2016-06-01

Although several studies reported increased oxidative stress in Hashimoto's thyroiditis (HT), the effect of levothyroxine treatment on oxidative status is not studied extensively. Therefore, we conducted this study to investigate the effects of levothyroxine replacement on oxidative stress in HT. Thirty-six patients recently diagnosed with HT-related hypothyroidism and 36 healthy controls were included in the study. Levothyroxine replacement was started to patients with hypothyroidism, and had been followed-up for 6 months. Mean basal serum total antioxidant status (TAS), total thiol, arylesterase, and paraoxonase 1 (PON1) levels were significantly lower, and serum total oxidant status (TOS) and oxidative stress index (OSI) were significantly higher in the patients with hypothyroid than the controls. In the hypothyroid group serum TAS, total thiol, arylesterase, and PON1 levels increased and serum TOS and OSI levels decreased significantly after levothyroxine treatment. Pretreatment serum TAS, total thiol, PON1, and arylesterase levels were positively correlated with free levothyroxine (fT4) and negatively correlated with thyroid-stimulating hormone (TSH), antithyroid peroxidase (anti-TPO), and antithyroglobulin (anti-TG) levels. Also, pretreatment serum TOS and OSI levels were negatively correlated with fT4 levels and positively correlated with TSH, anti-TPO, and anti-TG. We have also found that the fT4 and anti-TPO levels are independent predictors of the oxidative stress parameters in stepwise multivariable linear regression analysis. This study suggests that levothyroxine replacement decreases oxidant status and increases antioxidant status following the 6 months of levothyroxine replacement in hypothyroidism that develops in accordance with the HT. © 2016 European Society of Endocrinology.

Effects of Aftermarket Control Technologies on Gas and Particle Phase Oxidative Potential from Diesel Engine Emissions.

PubMed

Pavlovic, Jelica; Holder, Amara L; Yelverton, Tiffany L B

2015-09-01

Particulate matter (PM) originating from diesel combustion is a public health concern due to its association with adverse effects on respiratory and cardiovascular diseases and lung cancer. This study investigated emissions from three stationary diesel engines (gensets) and varying power output (230 kW, 400 kW, and 600 kW) at 50% and 90% load to determine concentrations of gaseous (GROS) and PM reactive oxygen species (PMROS). In addition, the influence of three modern emission control technologies on ROS emissions was evaluated: active and passive diesel particulate filters (A-DPF and P-DPF) and a diesel oxidation catalyst (DOC). PMROS made up 30-50% of the total ROS measured without aftermarket controls. All applied controls removed PMROS by more than 75% on average. However, the oxidative potential of PM downstream of these devices was not diminished at the same rate and particles surviving the A-PDF had an even higher oxidative potential on a per PM mass basis compared to the particles emitted by uncontrolled gensets. Further, the GROS as compared to PMROS emissions were not reduced with the same efficiency (<36%). GROS concentrations were highest with the DOC in use, indicating continued formation of GROS with this control. Correlation analyses showed that PMROS and to a lesser extent GROS have a good correlation with semivolatile organic carbon (OC1) subfraction. In addition, results suggest that chemical composition, rather than PM size, is responsible for differences in the PM oxidative potential.

Effects of stanozolol on apoptosis mechanisms and oxidative stress in rat cardiac tissue.

PubMed

Kara, Mehtap; Ozcagli, Eren; Kotil, Tuğba; Alpertunga, Buket

2018-06-01

Stanozolol is a widely used 17α-alkylated anabolic androgenic steroid (AAS) derivative. Despite stanozolol's adverse effects, its effect on oxidative stress parameters and mitochondrial apoptosis pathway is not clearly defined. In our study, thirty four male Sprague-Dawley rats were divided into 5 groups as control (C), vehicle control (VC), steroid (ST), vehicle control-exercise (VCE), and steroid-exercise (STE). Animals were subcutaneously administered stanozolol 5 mg/kg in steroid groups and propylene glycol 1 ml/kg in the vehicle-control groups. On the 28th day-after sacrification, oxidative stress (MDA, GSH, PC, SOD, CAT) and apoptosis parameters (TUNEL, Cytochrome-c) in cardiac tissue were evaluated. Also, blood vessel morphology of cardiac tissue was evaluated with Verhoeff-van Giesen staining. It has been demonstrated that stanozolol administration triggers apoptosis by using TUNEL assay and cytochrome-c immunohistochemical staining intensity, while this effect is significantly reduced in the presence of exercise. In conclusion, the present study demonstrated that stanozolol administration induces apoptosis with increasing PC and CAT levels, while GSH, MDA and SOD parameters do not reveal any significant change. Exercise has a protective role in stanozolol induced oxidative stress and apoptosis. According to Verhoeff-van Giesen staining results for blood vessel morphology assessment, it has been seen that exercise has a protective role on cardiac blood vessels. This mechanism needs further investigations with long term exposure studies for clarifying possible pathways. Copyright © 2018 Elsevier Inc. All rights reserved.

Oxidative Stress in BPH.

PubMed

Savas, M; Verit, A; Ciftci, H; Yeni, E; Aktan, E; Topal, U; Erel, O

2009-01-01

In the present study, we investigated the relationship between potency of oxidative stress and BPH and this may assist to contribute to the realistic explanation of the ethiopathogenesis of BPH. Seventy four newly diagnosed men with BPH (mean age: 54+/-11.2), who had not undergone any previous treatment for BPH, and 62 healthy volunteers (mean age: 55+/-14) were enrolled in the present study. To determine the antioxidative status of plasma, total antioxidant capacity (TAC) was calculated, and to determine the oxidative status of plasma (TOS) total peroxide levels were measured. The ratio of TAC to total peroxide was accepted as an indicator of oxidative stress (OSI). Data are presented as mean SD +/- unless specified. Student t-test and correlation analyses were used to evaluate the statistical significance differences in the median values recorded for all parameters between BPH and control group. Plasma TAC TOS were found in patients and controls (1.70 +/- 0.32, 1.68 +/- 0.19 micromol Trolox Equiv./L), (12.48 +/- 1.98, 12.40 +/- 1.14 micromol / L) respectively. OSI was calculated as 7.57 +/- 1.91, 7.48 +/- 1.33, respectively. Plasma TAC, TOS and OSI levels were not found to be significantly difference between patients and control subjects (p>0.05, p>0.05, p>0.05). The present study has shown that there were not relationship between potency of oxidative stress and BPH. Further well designed studies should be planned to find out whether the oxidative stress-related parameters play role in BPH as an interesting pathology in regard of the etiopathogenesis.

Rotenone, Paraquat, and Parkinson’s Disease

PubMed Central

Tanner, Caroline M.; Kamel, Freya; Ross, G. Webster; Hoppin, Jane A.; Goldman, Samuel M.; Korell, Monica; Marras, Connie; Bhudhikanok, Grace S.; Kasten, Meike; Chade, Anabel R.; Comyns, Kathleen; Richards, Marie Barber; Meng, Cheryl; Priestley, Benjamin; Fernandez, Hubert H.; Cambi, Franca; Umbach, David M.; Blair, Aaron; Sandler, Dale P.; Langston, J. William

2011-01-01

Background Mitochondrial dysfunction and oxidative stress are pathophysiologic mechanisms implicated in experimental models and genetic forms of Parkinson’s disease (PD). Certain pesticides may affect these mechanisms, but no pesticide has been definitively associated with PD in humans. Objectives Our goal was to determine whether pesticides that cause mitochondrial dysfunction or oxidative stress are associated with PD or clinical features of parkinsonism in humans. Methods We assessed lifetime use of pesticides selected by mechanism in a case–control study nested in the Agricultural Health Study (AHS). PD was diagnosed by movement disorders specialists. Controls were a stratified random sample of all AHS participants frequency-matched to cases by age, sex, and state at approximately three controls: one case. Results In 110 PD cases and 358 controls, PD was associated with use of a group of pesticides that inhibit mitochondrial complex I [odds ratio (OR) = 1.7; 95% confidence interval (CI), 1.0–2.8] including rotenone (OR = 2.5; 95% CI, 1.3–4.7) and with use of a group of pesticides that cause oxidative stress (OR = 2.0; 95% CI, 1.2–3.6), including paraquat (OR = 2.5; 95% CI, 1.4–4.7). Conclusions PD was positively associated with two groups of pesticides defined by mechanisms implicated experimentally—those that impair mitochondrial function and those that increase oxidative stress—supporting a role for these mechanisms in PD pathophysiology. PMID:21269927

Oxidative stress in major depressive and anxiety disorders, and the association with antidepressant use; results from a large adult cohort.

PubMed

Black, C N; Bot, M; Scheffer, P G; Penninx, B W J H

2017-04-01

Oxidative stress has been implicated in the pathophysiology of major depressive disorder (MDD) and anxiety disorders and may be influenced by antidepressant use. This study investigated the association of oxidative stress, measured by plasma levels of F2-isoprostanes and 8-hydroxy-2'-deoxyguanosine (8-OHdG) reflecting oxidative lipid and DNA damage respectively, with MDD, anxiety disorders and antidepressant use in a large cohort. Data was derived from the Netherlands Study of Depression and Anxiety including patients with current (N = 1619) or remitted (N = 610) MDD and/or anxiety disorder(s) (of which N = 704 antidepressant users) and 612 controls. Diagnoses were established with the Composite International Diagnostic Interview. Plasma 8-OHdG and F2-isoprostanes were measured using LC-MS/MS. ANCOVA was performed adjusted for sampling, sociodemographic, health and lifestyle variables. F2-isoprostanes did not differ between controls and patients, or by antidepressant use. Patients with current disorders had lower 8-OHdG (mean 42.1 pmol/l, 95% CI 40.4-43.8) compared to controls (45.0 pmol/l, 95% CI 42.9-47.2; p < 0.001) after adjustment for sampling, sociodemographics and lifestyle, but these differences disappeared after further adjustment for antidepressant use (p = 0.562). Antidepressant users had lower 8-OHdG levels (38.2 pmol/l, 95% CI 36.5-39.9) compared to controls (44.9 pmol/l, 95% CI 43.2-46.6; Cohen's d = 0.21, p < 0.001). Results for 8-OHdG were comparable across disorders (MDD and/or anxiety disorders), and all antidepressant types (SSRIs, TCAs, other antidepressants). Contrary to previous findings this large-scale study found no increased oxidative stress in MDD and anxiety disorders. Antidepressant use was associated with lower oxidative DNA damage, suggesting antidepressants may have antioxidant effects.

Paraoxonase gene Q192R & L55M polymorphisms in Indians with acute myocardial infarction & association with oxidized low density lipoprotein.

PubMed

Lakshmy, Ramakrishnan; Ahmad, Dilawar; Abraham, Rani Ann; Sharma, Mukta; Vemparala, Kranthi; Das, Siuli; Reddy, K Srinath; Prabhakaran, Dorairaj

2010-04-01

Paraoxonase (PON) is an HDL associated ester hydrolase with an ability to retard LDL oxidation in vitro by preventing lipid peroxide generation. The population variability in enzyme activity is attributed to polymorphisms in paraoxonase gene. For example, polymorphism at codon 192 and 55 of the paraoxonase gene has been reported to be associated with coronary heart disease (CAD) and diabetes among different ethnic groups. The present study looks at PON192 and 55 polymorphism among hospitalized Asian Indian patients with myocardial infarction (MI) and their association with circulating oxidized LDL and antioxidant status. One hundred and twenty four consecutive patients of acute myocardial infarction and 221 age-matched controls were recruited for the study. Oxidized LDL was measured in serum by ELISA and total antioxidant levels by the 2,2'-azino-bis-(3 ethyl benzothiozoline-6-sulfonate) (ABTS) method. Other known cardiovascular risk factors, apolipoprotein B, apolipoproteinA1, lipoprotein(a), hsCRP and homocysteine were also measured. Paraoxonase gene polymorphism at codon 192 and 55 were analyzed by PCR-RFLP. Patients with MI had significantly higher oxidized LDL (P<0.05) and lower total antioxidant capacity (P<0.001) as compared to controls. Oxidized LDL correlated with total cholesterol, LDL and Apo B in patients. B allele frequency of the codon 192 polymorphism in paraoxonase gene was higher in cases as compared to controls and odds ratio of developing the MI with BB genotype versus AA genotype was 2.37, (P=0.044). Codon 55 polymorphism in paraoxonase gene was not associated with CAD. There was no difference in oxidized LDL between the different genotypes of PON192 and PON55. Although PON192 polymorphism was associated with CAD, no correlation of PON192 or 55 polymorphism was found with oxidized LDL suggesting that presence of other antioxidant factors may be of equal importance in preventing LDL oxidation.

Physical Form of Dietary Fat Alters Postprandial Substrate Utilization and Glycemic Response in Healthy Chinese Men.

PubMed

Tan, Sze-Yen; Peh, Elaine; Lau, Evelyn; Marangoni, Alejandro G; Henry, Christiani Jeyakumar

2017-06-01

Background: Dietary fats elicit various physiological responses, with the physical form of fat reported to alter fat digestion and absorption. Objectives: The primary aims were to compare the effects of dietary fat in 2 physical forms (liquid and oleogel) and 2 degrees of saturation (saturated and polyunsaturated) on postprandial energy expenditure (EE) and substrate oxidation, glycemia, and appetite. Methods: The study was a randomized, controlled crossover trial. Sixteen normal-weight, healthy Chinese men completed the study [mean ± SD age: 28 ± 6 y; body mass index (in kg/m 2 ): 22.9 ± 3.1]. After an overnight fast, participants had their body weight measured and entered an indirect whole-room calorimeter (WRC). After baseline measurements, participants consumed orange juice and rice porridge alone (control), with 22.25 g coconut oil or sunflower oil or with 25 g coconut oleogel or sunflower oleogel in random order with a 5-d washout period between treatments. EE, substrate oxidation, capillary blood glucose, and appetite were measured over 195 min in a WRC. Participants completed a meal challenge to assess appetite. Test meals effects were compared by using repeated-measures ANOVA. Results: Fat saturation did not affect all study outcomes significantly. When data were pooled based on the physical form of dietary fat, EE did not differ. However, significantly higher carbohydrate oxidation ( P = 0.03) and a trend of lower fat oxidation ( P = 0.07) were found after the liquid oil than after the oleogel or control treatments. Postprandial capillary glucose was also significantly lower after the liquid oil than after the oleogel or control treatments ( P < 0.001). Appetite was not affected by the physical form and the saturation of dietary fats. Conclusions: The saturation of dietary fat did not affect postprandial glucose, EE, substrate oxidation, or appetite. However, oleogel prevented the glycemic-lowering and fat-oxidation effects induced by liquid oil in Chinese men. Future work on oleogel should focus on cardiometabolic risk factors. This study was registered at clinicaltrials.gov as NCT02702726. © 2017 American Society for Nutrition.

Iron homeostatis and oxidative stress in idiopathic pulmonary alveolar proteinosis: a case-control study

EPA Science Inventory

ABSTRACT: BACKGROUND: Lung injury caused by both inhaled dusts and infectious agents depends on increased availability of iron and metal-catalyzed oxidative stress. Because inhaled particles, such as silica, and certain infections can cause secondary pulmonary alveolar proteinosi...

Impaired Arginine Metabolism Coupled to a Defective Redox Conduit Contributes to Low Plasma Nitric Oxide in Polycystic Ovary Syndrome.

PubMed

Krishna, Meera B; Joseph, Annu; Thomas, Philip Litto; Dsilva, Belinda; Pillai, Sathy M; Laloraya, Malini

2017-01-01

Though oxidative stress is associated with Polycystic Ovary Syndrome (PCOS), the status of nitric oxide is still unclear. Nitric Oxide (NO) plays pivotal roles in many physiological functions which are compromised in PCOS. Our recent study reveals lowered T-regulatory cells (Tregs) in PCOS, and Treg generation is known to be regulated by NO levels. However concrete evidences are lacking on mechanisms modulating NO levels under PCOS. This is a retrospective case-control cohort study, comprised of PCOS women (N=29) and normal menstruating women as controls (N=20). We analysed NOx (nitrite+nitrate) and hydrogen peroxide (H2O2) concentrations, transcript levels of endothelial nitric oxide synthase (eNOS)/inducible nitric oxide synthase (iNOS) and arginine modulators, hydrogen peroxide regulators in the cohort. PCOS women showed reduced plasma NOx(nitrate+nitrite) and H2O2 compared to controls. We report reduction in transcript levels of iNOS/NOS2 and eNOS/NOS3 in PCOS peripheral blood. The transcripts involved in arginine bioavailability: Argininosuccinate lyase (ASL), Solute Carrier Family1, member 7 (SLC7A1) and Arginase 1 (ARG1) and Asymmetric Dimethyl Arginine (ADMA) metabolism: Protein arginine methyltransferase 1 (PRMT1) and Dimethylarginine dimethylaminohydrolase 2 (DDAH2) also showed differential expression. H2O2 concentration in PCOS women was also found to be reduced. The reduction can be attributed to increase in catalase levels as a consequence of the body's effort to alleviate the oxidative burden in the system. Our study advocates that PCOS women have lowered NO due to reduced iNOS/eNOS expression, low H2O2, high ADMA synthesis and reduced arginine bioavailability. An in-depth analysis of redox biology of PCOS to open up potential therapeutic strategies is highly recommended. © 2017 The Author(s). Published by S. Karger AG, Basel.

Oxidative stress biomarkers and clinical dimensions in first 10 years of schizophrenia.

PubMed

González-Blanco, Leticia; García-Portilla, María Paz; García-Álvarez, Leticia; de la Fuente-Tomás, Lorena; Iglesias García, Celso; Sáiz, Pilar A; Rodríguez-González, Susana; Coto-Montes, Ana; Bobes, Julio

2018-04-21

Several studies have described increased oxidative stress parameters in patients with schizophrenia. The objectives of the current study were to identify potential oxidative stress biomarkers in stable patients during first 10 years of schizophrenia and determine if they are associated with specific clinical dimensions. Seventy-three clinically stable outpatients with schizophrenia and 73 sex and age-matched healthy controls were recruited. Sociodemographic, clinical and biological data were collected at enrollment. Blood biomarkers included homocysteine, the percentage of hemolysis, lipid peroxidation subproducts, and as an antioxidant biomarker, catalase activity in erythrocytes. Comparative analyses after controlling for smoking and metabolic syndrome evidenced a significant increase in catalase activity in patients. Also, lower lipid peroxidation levels showed an association with negative symptoms. In conclusion, compensatory antioxidant mechanisms might be increased in stable patients with schizophrenia at early stages. Furthermore, there may be an inverse relationship between oxidative stress and negative dimension. Copyright © 2018 SEP y SEPB. Publicado por Elsevier España, S.L.U. All rights reserved.

High resolution and comprehensive techniques to analyze aerobic methane oxidation in mesocosm experiments

NASA Astrophysics Data System (ADS)

Chan, E. W.; Kessler, J. D.; Redmond, M. C.; Shiller, A. M.; Arrington, E. C.; Valentine, D. L.; Colombo, F.

2015-12-01

Many studies of microbially mediated aerobic methane oxidation in oceanic environments have examined the many different factors that control the rates of oxidation. However, there is debate on how quickly methane is oxidized once a microbial population is established and what factor(s) are limiting in these types of environments. These factors include the availability of CH4, O2, trace metals, nutrients, and the density of cell population. Limits to these factors can also control the temporal aspects of a methane oxidation event. In order to look at this process in its entirety and with higher temporal resolution, a mesocosm incubation system was developed with a Dissolved Gas Analyzer System (DGAS) coupled with a set of analytical tools to monitor aerobic methane oxidation in real time. With the addition of newer laser spectroscopy techniques (cavity ringdown spectroscopy), stable isotope fractionation caused by microbial processes can also be examined on a real time and automated basis. Cell counting, trace metal, nutrient, and DNA community analyses have also been carried out in conjunction with these mesocosm samples to provide a clear understanding of the biology in methane oxidation dynamics. This poster will detail the techniques involved to provide insights into the chemical and isotopic kinetics controlling aerobic methane oxidation. Proof of concept applications will be presented from seep sites in the Hudson Canyon and the Sleeping Dragon seep field, Mississippi Canyon 118 (MC 118). This system was used to conduct mesocosm experiments to examine methane consumption, O2 consumption, nutrient consumption, and biomass production.

[Research of the surface oxide film on anodizing Ni-Cr porcelain alloy].

PubMed

Zhu, Song; Sun, Hong-Chen; Zhang, Jing-Wei; Li, Zong-Hui

2006-08-01

To study the shape, thickness and oxide percentage of major metal element of oxide film on Ni-Cr porcelain alloy after anodizing pretreatment. 10 samples were made and divided into 2 groups at random. Then after surface pretreatment, the oxide films of two samples of each group were analyzed using electronic scanning microscope. The rest 3 samples were measured by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Lightly selective solution appeared because the different component parts of the alloy have dissimilar electrode, whose dissolve velocity were quite unlike. The sample's metal surface expanded, so the mechanical interlocking of porcelain and metal increased bond strength. The thickness of oxide film was 1.72 times of the control samples. The oxide percentage of major metal elements such as Cr, Ni and Mo were higher, especially Cr. It initially involved the formation of a thin oxide bound to the alloy and second, the ability of the formed oxide to saturate the porcelain, completing the chemical bond of porcelain to metal. The method of anodizing Ni-Cr porcelain alloy can easily control the forming of oxide film which was thin and its surface pattern was uniform. It is repeated and a good method of surface pretreatment before firing cycle.

Inhibition of serum cholesterol oxidation by dietary vitamin C and selenium intake in high fat fed rats.

PubMed

Menéndez-Carreño, M; Ansorena, D; Milagro, F I; Campión, J; Martínez, J A; Astiasarán, I

2008-04-01

Cholesterol oxidation products (COPs) have been considered as specific in vivo markers of oxidative stress. In this study, an increased oxidative status was induced in Wistar rats by feeding them a high-fat diet (cafeteria diet). Another group of animals received the same diet supplemented with a combination of two different antioxidants, ascorbic acid (100 mg/kg rat/day) and sodium selenite (200 microg/kg rat/day) and a third group fed on a control diet. Total and individual COPs analysis of the different diets showed no differences among them. At the end of the experimental trial, rats were sacrificed and serum cholesterol, triglycerides and COPs were measured. None of the diets induced changes in rats body weight, total cholesterol and triglycerides levels. Serum total COPs in rats fed on the high-fat diet were 1.01 microg/ml, two times the amount of the control rats (0.47 microg/ml). When dietary antioxidant supplementation was given, serum total COPs concentration (0.44 microg/ml) showed the same levels than those of the rats on control diet. 7beta-hydroxycholesterol, formed non-enzymatically via cholesterol peroxidation in the presence of reactive oxygen species, showed slightly lower values in the antioxidant-supplemented animals compared to the control ones. This study confirms the importance of dietary antioxidants as protective factors against the formation of oxysterols.

Evaluation of oxidative stress and antioxidant status: Correlation with the severity of sepsis.

PubMed

Kumar, S; Gupta, E; Kaushik, S; Kumar Srivastava, V; Mehta, S K; Jyoti, A

2018-04-01

Sepsis is a condition caused by infection followed by unregulated inflammatory response which may lead to the organ dysfunction. During such condition, over-production of oxidants is one of the factors which contribute cellular toxicity and ultimately organ failure and mortality. Antioxidants having free radicals scavenging activity exert protective role in various diseases. This study has been designed to evaluate the levels of oxidative and antioxidative activity in sepsis patients and their correlation with the severity of the sepsis. A total of 100 sepsis patients and 50 healthy controls subjects were enrolled in this study from the period October 2016 to June 2017. The investigation included measurements of oxidative enzyme, myeloperoxidase (MPO), antioxidant enzymes including superoxide dismutase activity (SOD) and catalase activity (CAT) and cytokines (TNF-α, IL-8 and IFN-γ). Furthermore, the level of these activities was correlated with severity of sepsis. Augmented levels of oxidants were found in sepsis as demonstrated by DMPO nitrone adduct formation and plasma MPO level activity (1.37 ± 0.51 in sepsis vs 0.405 ± 0.16 in control subjects). Cytokines were also found to be increased in sepsis patients. However, plasma SOD and CAT activities were significantly attenuated (P < .001) in the sepsis patients compared with controls subjects. Moreover, inverse relation between antioxidant enzymes (SOD and CAT) and organ failure assessment (SOFA), physiological score (APACHE II), organ toxicity specific markers have been observed as demonstrated by Pearson's correlation coefficient. This study suggests that imbalance between oxidant and antioxidant plays key role in the severity of sepsis. © 2018 The Foundation for the Scandinavian Journal of Immunology.

Band edge engineering of oxide photoanodes for photoelectrochemical water splitting: Integration of subsurface dipoles with atomic-scale control

DOE PAGES

Hikita, Yasuyuki; Nishio, Kazunori; Seitz, Linsey C.; ...

2016-01-22

One of the crucial parameters dictating the efficiency of photoelectrochemical water-splitting is the semiconductor band edge alignment with respect to hydrogen and oxygen redox potentials. Despite the importance of metal oxides in their use as photoelectrodes, studies to control the band edge alignment in aqueous solution have been limited predominantly to compound semiconductors with modulation ranges limited to a few hundred mV. The ability to modulate the flat band potential of oxide photoanodes by as much as 1.3 V, using the insertion of subsurface electrostatic dipoles near a Nb-doped SrTiO 3/aqueous electrolyte interface is reported. Lastly, the tunable range achievedmore » far exceeds previous reports in any semiconductor/aqueous electrolyte system and suggests a general design strategy for highly efficient oxide photoelectrodes.« less

Lack of association between nuclear factor erythroid-derived 2-like 2 promoter gene polymorphisms and oxidative stress biomarkers in amyotrophic lateral sclerosis patients.

PubMed

LoGerfo, Annalisa; Chico, Lucia; Borgia, Loredana; Petrozzi, Lucia; Rocchi, Anna; D'Amelio, Antonia; Carlesi, Cecilia; Caldarazzo Ienco, Elena; Mancuso, Michelangelo; Siciliano, Gabriele

2014-01-01

Oxidative stress involvement has been strongly hypothesized among the possible pathogenic mechanisms of motor neuron degeneration in amyotrophic lateral sclerosis (ALS). The intracellular redox balance is finely modulated by numerous complex mechanisms critical for cellular functions, among which the nuclear factor erythroid-derived 2-like 2 (NFE2L2/Nrf2) pathways. We genotyped, in a cohort of ALS patients (n = 145) and healthy controls (n = 168), three SNPs in Nrf2 gene promoter: -653 A/G, -651 G/A, and -617 C/A and evaluated, in a subset (n = 73) of patients, advanced oxidation protein products (AOPP), iron-reducing ability of plasma (FRAP), and plasma thiols (-SH) as oxidative damage peripheral biomarkers. Nrf2 polymorphisms were not different among patients and controls. Increased levels of AOPP (P < 0.05) and decreased levels of FRAP (P < 0.001) have been observed in ALS patients compared with controls, but no difference in -SH values was found. Furthermore, no association was found between biochemical markers of redox balance and Nrf2 polymorphisms. These data confirm an altered redox balance in ALS and indicate that, while being abnormally modified compared to controls, the oxidative stress biomarkers assessed in this study are independent from the -653 A/G, -651 G/A, and -617 C/A Nrf2 SNPs in ALS patients.

Cardiotoxicity induced by dietary oxidized sunflower oil in rats: pro- and antioxidant effects of α-tocopherol.

PubMed

Rouaki, Fayrouz; Mazari, Azzedine; Kanane, Amel; Errahmani, Mohamed Brahim; Ammouche, Ali

2013-01-01

This study highlighted the pro-oxidative functions of α-tocopherol (αT) on the heart antioxidant system and tissue histopathology of oxidized sunflower oil (OSO)-exposed rats.Four groups of male Wistar rats were fed with different diets: 1) control diet containing FSO (fresh sunflower oil); 2) diet containing 5 % OSO; 3) diet containing 5 % OSO, supplemented with 600 mg αT kg-1; and 4) diet containing 5 % OSO, supplemented with 1200 mg αT kg-1. The hearts were then isolated, and the antioxidant enzymatic activities were assessed. Body weight and catalase (CAT), glutathione peroxidase (GPx) activities significantly decreased in groups fed with OSO, while the lipid peroxidation (LPO) level significantly increased. Administration of OSO with αT (600 mg · kg-1) returned the body weight values and LPO levels to similar values as the control group. The CAT and GPx activities increased but remained significantly lower compared to the control group. In the OSO group with αT (1200 mg · kg-1), the CAT and GPx activities also decreased, while LPO significantly increased. Heart tissue sections obtained from the groups revealed the presence of large areas of necrosis. This study suggested that OSO induced oxidative stress and that administration of a moderate dose of αT restored the antioxidant balance, but that high levels of αT supplementation result in a pro-oxidant effect.

Nrf2-Mediated Neuroprotection Against Recurrent Hypoglycemia Is Insufficient to Prevent Cognitive Impairment in a Rodent Model of Type 1 Diabetes.

PubMed

McNeilly, Alison D; Gallagher, Jennifer R; Dinkova-Kostova, Albena T; Hayes, John D; Sharkey, John; Ashford, Michael L J; McCrimmon, Rory J

2016-10-01

It remains uncertain whether recurrent nonsevere hypoglycemia (Hypo) results in long-term cognitive impairment in type 1 diabetes (T1D). This study tested the hypothesis that specifically in the T1D state, Hypo leads to cognitive impairment via a pathological response to oxidative stress. Wild-type (Control) and nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) null mice were studied. Eight groups of mice (Control and Nrf2(-/-) ± T1D and ± Hypo) were subject to recurrent, twice-weekly, insulin or saline injections over 4 weeks, after which cognitive function was assessed and brain tissue analyzed. Recurrent moderate hypoglycemia in T1D, but not Control, mice significantly impaired cognitive performance, and this was associated with hippocampal oxidative damage and inflammation despite an enhanced expression of Nrf2 and its target genes Hmox1 and Nqo1 In Nrf2(-/-) mice, both T1D and Hypo independently resulted in impaired cognitive performance, and this was associated with oxidative cell damage and marked inflammation. Together, these data suggest that Hypo induces an Nrf2-dependent antioxidant response in the hippocampus, which counteracts oxidative damage. However, in T1D, this neuroprotective mechanism is insufficient to prevent neuronal oxidative damage, resulting in chronic deficits in working and long-term memory. © 2016 by the American Diabetes Association.

Evaluation of lipid oxidative stress status and inflammation in atopic ocular surface disease

PubMed Central

Wakamatsu, Tais H.; Ayako, Igarashi; Takano, Yoji; Matsumoto, Yukihiro; Ibrahim, Osama M.A.; Okada, Naoko; Satake, Yoshiyuki; Fukagawa, Kazumi; Shimazaki, Jun; Tsubota, Kazuo; Fujishima, Hiroshi

2010-01-01

Background Although the oxidative stress status in atopic skin disease has been reported to be elevated, there are still no studies related to the status of oxidative stress in atopic ocular surface disease. The purpose of this study was to evaluate the ocular surface lipid oxidative stress status and inflammation in atopic keratoconjunctivitis (AKC) patients and normal subjects. Methods Twenty eight eyes of 14 patients (9 males, 5 females) with AKC and 18 eyes of 9 age and sex matched (4 males and 5 females) normal healthy controls were examined in this prospective study. The severity of atopic dermatitis (AD) was scored by the SCORing Atopic Dermatitis (SCORAD) index. All subjects underwent Schirmer test, tear film break up time (BUT), fluorescein/Rose Bengal stainings, tear collection, and brush cytology from the upper palpebral conjunctiva. The brush cytology samples were stained with Diff-Quik for differentiation of inflammatory cells and immunohistochemistry (IHC) staining with HEL (hexanoyl-lysine) and 4-HNE (4-hydroxy-2-nonenal) to study lipid oxidation. HEL and cytokine (interleukin-4 (IL-4), interleukin-5 (IL-5), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ)) levels were measured by enzyme-linked immunosorbent assay (ELISA) from tear samples of AKC patients and control subjects. Toluidine Blue and IHC staining with HEL, 4-HNE and cluster of differentiation 45 (CD45) were performed on papillary samples of AKC patients. This study was conducted in compliance with the “Declaration of Helsinki.” Results The tear stability and vital staining scores were significantly worse in eyes of AKC patients (p<0.05) compared to the controls. Inflammatory cells and positively stained conjunctival epithelial cells for HEL and 4-HNE showed a significant elevation in brush cytology samples of AKC patients. Significantly higher levels of HEL and cytokines were detected in tears of AKC patients compared to controls. Papillary specimens also revealed many CD45 inflammatory cells as well as many cells positively stained with HEL and 4-HNE in IHC. A strong significant linear positive correlation between conjunctival inflammation and epithelial lipid oxidative stress status was observed. Conjunctival lipid oxidative stress also correlated strongly with tear HEL levels and epithelial damage scores. Conclusions The ocular surface disease in AKC was characterized by marked tear instability, ocular surface epithelial damage, increase in inflammatory infiltrates and presence of increased lipid oxidation. PMID:21139696

Evaluation of dynamic thiol/disulphide homeostasis as a novel indicator of oxidative stress in maple syrup urine disease patients under treatment.

PubMed

Zubarioglu, Tanyel; Kiykim, Ertugrul; Cansever, Mehmet Serif; Neselioglu, Salim; Aktuglu-Zeybek, Cigdem; Erel, Ozcan

2017-02-01

Maple syrup urine disease (MSUD) is a metabolic disorder that is caused by deficiency of branched-chain α-keto acid dehydrogenase complex. Although accumulation of toxic metabolites is associated with neurotoxicity, mechanisms underlying brain damage remain unclear. Aim of this study is to evaluate thiol/disulphide homeostasis as a novel indicator of oxidative stress in MSUD patients under treatment. Twenty patients with MSUD and 20 healthy individuals were included in study. All patients were under regular follow-up and had a good metabolic control. Serum native thiol (-SH), total thiol (-SH + -S-S-), disulphide (-S-S) levels were measured in all subjects. Disulphide/native thiol, disulphide/total thiol and native thiol/total thiol ratios were calculated from these values. Simultaneous blood sampling for plasma quantitative amino acid analysis was performed in both groups. Any significant difference was not observed in -SH, -SH + -S-S-, -S-S levels between two groups. In addition no increase of disulphide/native thiol and disulphide/total thiol ratios was detected in patient group. This study is the first study that evaluates dynamic thiol/disulphide homeostasis as an indicator of oxidative stress in MSUD patients. Among previous studies that were made to determine oxidative stress in treated MSUD patients, this study had the largest sample size also. In recent studies, it was claimed that oxidative stress could be responsible from neurotoxicity even in treated patients. Here, dynamic thiol/disulfide homeostasis status showed that providing good metabolic control in MSUD patients prevent oxidative stress. Under regular follow-up and good compliance with diet, additional antioxidant therapies would possibly not be necessary.

Assessment of oxidative stress markers in recurrent pregnancy loss: a prospective study.

PubMed

Yiyenoğlu, Özgür Bilgin; Uğur, Mete Gürol; Özcan, Hüseyin Çağlayan; Can, Günay; Öztürk, Ebru; Balat, Özcan; Erel, Özcan

2014-06-01

To determine the levels of oxidative stress markers in recurrent pregnancy loss using a novel automated method. 30 pregnant women in their first trimester with a history of recurrent pregnancy loss (RPL) and 30 healthy pregnant women were enrolled in this prospective controlled study. Total antioxidant capacity (TAC), total oxidant level (TOL) and oxidative stress index (OSI) in maternal serum were measured using the more recently designated Erel method. We observed statistically significant increased TOL and OSI levels in patient group (p = 0.032, p = 0.007, respectively). We also demonstrated statistically significant decreased TAC in pregnant women who had a history of RPL (p = 0.013). Our results support the concept that oxidative stress plays a central role in the etiopathogenesis of RPL. Further studies to evaluate the predictive role of TAC, TOL, OSI levels using Erel method are needed.

Control of spontaneous emission of quantum dots using correlated effects of metal oxides and dielectric materials

NASA Astrophysics Data System (ADS)

Sadeghi, S. M.; Wing, W. J.; Gutha, R. R.; Capps, L.

2017-03-01

We study the emission dynamics of semiconductor quantum dots in the presence of the correlated impact of metal oxides and dielectric materials. For this we used layered material structures consisting of a base substrate, a dielectric layer, and an ultrathin layer of a metal oxide. After depositing colloidal CdSe/ZnS quantum dots on the top of the metal oxide, we used spectral and time-resolved techniques to show that, depending on the type and thickness of the dielectric material, the metal oxide can characteristically change the interplay between intrinsic excitons, defect states, and the environment, offering new material properties. Our results show that aluminum oxide, in particular, can strongly change the impact of amorphous silicon on the emission dynamics of quantum dots by balancing the intrinsic near band emission and fast trapping of carriers. In such a system the silicon/aluminum oxide charge barrier can lead to large variation of the radiative lifetime of quantum dots and control of the photo-ejection rate of electrons in quantum dots. The results provide unique techniques to investigate and modify physical properties of dielectrics and manage optical and electrical properties of quantum dots.

Control of spontaneous emission of quantum dots using correlated effects of metal oxides and dielectric materials.

PubMed

Sadeghi, S M; Wing, W J; Gutha, R R; Capps, L

2017-03-03

We study the emission dynamics of semiconductor quantum dots in the presence of the correlated impact of metal oxides and dielectric materials. For this we used layered material structures consisting of a base substrate, a dielectric layer, and an ultrathin layer of a metal oxide. After depositing colloidal CdSe/ZnS quantum dots on the top of the metal oxide, we used spectral and time-resolved techniques to show that, depending on the type and thickness of the dielectric material, the metal oxide can characteristically change the interplay between intrinsic excitons, defect states, and the environment, offering new material properties. Our results show that aluminum oxide, in particular, can strongly change the impact of amorphous silicon on the emission dynamics of quantum dots by balancing the intrinsic near band emission and fast trapping of carriers. In such a system the silicon/aluminum oxide charge barrier can lead to large variation of the radiative lifetime of quantum dots and control of the photo-ejection rate of electrons in quantum dots. The results provide unique techniques to investigate and modify physical properties of dielectrics and manage optical and electrical properties of quantum dots.

Placental oxidative stress and maternal endothelial function in pregnant women with normotensive fetal growth restriction.

PubMed

Yoshida, Atsumi; Watanabe, Kazushi; Iwasaki, Ai; Kimura, Chiharu; Matsushita, Hiroshi; Wakatsuki, Akihiko

2018-04-01

The purpose of this study was to investigate the relationship between placental oxidative stress and maternal endothelial function in pregnant women with normotensive fetal growth restriction (FGR). We examined serum concentrations of oxygen free radicals (d-ROMs), maternal angiogenic factor (PlGF), and sFlt-1, placental oxidative DNA damage, and maternal endothelial function in 17 women with early-onset preeclampsia (PE), 18 with late-onset PE, 14 with normotensive FGR, and 21 controls. Flow-mediated vasodilation (FMD) was assessed as a marker of maternal endothelial function. Immunohistochemical analysis was performed to measure the proportion of placental trophoblast cell nuclei staining positive for 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage. Maternal serum d-ROM, sFlt-1 concentrations, and FMD did not significantly differ between the control and normotensive FGR groups. The proportion of nuclei staining positive for 8-OHdG was significantly higher in the normotensive FGR group relative to the control group. Our findings demonstrate that, despite the presence of placental oxidative DNA damage as observed in PE patients, pregnant women with normotensive FGR show no increase in the concentrations of sFlt-1 and d-ROMs, or a decrease in FMD.

Effect of replacing dietary vitamin E by sage on performance and meatiness of spent hens, and the oxidative stability of sausages produced from their meat.

PubMed

Loetscher, Y; Kreuzer, M; Albiker, D; Stephan, R; Messikommer, R E

2014-01-01

A total of 3960 hens (half ISA Warren and half Dekalb White) were housed in 18 compartments with 220 hens each. The effect of replacing dietary vitamin E by sage on productivity, meat yield and oxidative stability of sausages was studied. One third of all animals received either a vitamin E deficient diet (negative control) or diets supplemented with 30 mg/kg α-tocopherylacetate (positive control) or 25 g sage leaves/kg. At slaughter, meat yield was assessed and sausages were produced (n = 12 per treatment). The omission of vitamin E did not impair the oxidative stability of the raw sausage material or the spiced sausages in comparison to the positive control. Sage supplementation improved oxidative stability after 7 m of frozen storage, but not after 1, 4 and 10 m. Spice addition during meat processing had an antioxidant effect regardless of dietary treatment. Diet supplementation of any type did not affect laying performance and sausage meat yield. Feeding antioxidants to spent hens seemed to be not as efficient as in growing chickens, while seasoning with spices during sausage production proved to be a feasible way to delay lipid oxidation.

Mechanism of selenite removal by a mixed adsorbent based on Fe-Mn hydrous oxides studied using X-ray absorption spectroscopy.

PubMed

Chubar, Natalia; Gerda, Vasyl; Szlachta, Małgorzata

2014-11-18

Selenium cycling in the environment is greatly controlled by various minerals, including Mn and Fe hydrous oxides. At the same time, such hydrous oxides are the main inorganic ion exchangers suitable (on the basis of their chemical nature) to sorb (toxic) anions, separating them from water solutions. The mechanism of selenite adsorption by the new mixed adsorbent composed of a few (amorphous and crystalline) phases [maghemite, MnCO3, and X-ray amorphous Fe(III) and Mn(III) hydrous oxides] was studied by extended X-ray absorption fine structure (EXAFS) spectroscopy [supported by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) data]. The complexity of the porous adsorbent, especially the presence of the amorphous phases of Fe(III) and Mn(III) hydrous oxides, is the main reason for its high selenite removal performance demonstrated by batch and column adsorption studies shown in the previous work. Selenite was bound to the material via inner-sphere complexation (via oxygen) to the adsorption sites of the amorphous Fe(III) and Mn(III) oxides. This anion was attracted via bidentate binuclear corner-sharing coordination between SeO3(2-) trigonal pyramids and both FeO6 and MnO6 octahedra; however, the adsorption sites of Fe(III) hydrous oxides played a leading role in selenite removal. The contribution of the adsorption sites of Mn(III) oxide increased as the pH decreased from 8 to 6. Because most minerals have a complex structure (they are seldom based on individual substances) of various crystallinity, this work is equally relevant to environmental science and environmental technology because it shows how various solid phases control cycling of chemical elements in the environment.

SPM oxidation and parallel writing on zirconium nitride thin films

NASA Astrophysics Data System (ADS)

Farkas, N.; Comer, J. R.; Zhang, G.; Evans, E. A.; Ramsier, R. D.; Dagata, J. A.

2005-07-01

Systematic investigation of the SPM oxidation process of sputter-deposited ZrN thin films is reported. During the intrinsic part of the oxidation, the density of the oxide increases until the total oxide thickness is approximately twice the feature height. Further oxide growth is sustainable as the system undergoes plastic flow followed by delamination from the ZrN-silicon interface keeping the oxide density constant. ZrN exhibits superdiffusive oxidation kinetics in these single tip SPM studies. We extend this work to the fabrication of parallel oxide patterns 70 nm in height covering areas in the square centimeter range. This simple, quick, and well-controlled parallel nanolithographic technique has great potential for biomedical template fabrication.

Meat processing and colon carcinogenesis: cooked, nitrite-treated, and oxidized high-heme cured meat promotes mucin-depleted foci in rats

PubMed Central

Santarelli, Raphaëlle L; Vendeuvre, Jean-Luc; Naud, Nathalie; Taché, Sylviane; Guéraud, Françoise; Viau, Michelle; Genot, Claude; Corpet, Denis E; Pierre, Fabrice H F

2010-01-01

Processed meat intake is associated with colorectal cancer risk, but no experimental study supports the epidemiologic evidence. To study the effect of meat processing on carcinogenesis promotion, we first did a 14-day study with 16 models of cured meat. Studied factors, in a 2 × 2 × 2 × 2 design, were muscle color (a proxy for heme level), processing temperature, added nitrite, and packaging. Fischer 344 rats were fed these 16 diets, and we evaluated fecal and urinary fat oxidation and cytotoxicity, three biomarkers of heme-induced carcinogenesis promotion. A principal component analysis allowed for selection of four cured meats for inclusion into a promotion study. These selected diets were given for 100 days to rats pretreated with 1,2-dimethylhydrazine. Colons were scored for preneoplastic lesions: aberrant crypt foci (ACF) and mucin-depleted foci (MDF). Cured meat diets significantly increased the number of ACF/colon compared with a no-meat control diet (P = 0.002). Only the cooked nitrite-treated and oxidized high heme meat significantly increased the fecal level of apparent total N-nitroso compounds (ATNC) and the number of MDF per colon compared with the no-meat control diet (P < 0.05). This nitrite-treated and oxidized cured meat specifically increased the MDF number compared with similar non nitrite-treated meat (P = 0.03) and with similar non oxidized meat (P = 0.004). Thus, a model cured meat, similar to ham stored aerobically, increased the number of preneoplastic lesions, which suggests colon carcinogenesis promotion. Nitrite treatment and oxidation increased this promoting effect, which was linked with increased fecal ATNC level. This study could lead to process modifications to make non promoting processed meat. PMID:20530708

Controlling site selectivity in Pd-catalyzed oxidative cross-coupling reactions.

PubMed

Lyons, Thomas W; Hull, Kami L; Sanford, Melanie S

2011-03-30

This paper presents a detailed investigation of the factors controlling site selectivity in the Pd-mediated oxidative coupling of 1,3-disubstituted and 1,2,3-trisubstituted arenes (aryl-H) with cyclometalating substrates (L~C-H). The influence of both the concentration and the steric/electronic properties of the quinone promoter are studied in detail. In addition, the effect of steric/electronic modulation of the carboxylate ligand is discussed. Finally, we demonstrate that substitution of the carboxylate for a carbonate X-type ligand leads to a complete reversal in site selectivity for many arene substrates. The origins of these trends in site selectivity are discussed in the context of the mechanism of Pd-catalyzed oxidative cross-coupling.

Vitamin E Deficiency and Oxidative Status are Associated with Prediabetes in Apparently Healthy Subjects.

PubMed

Rodríguez-Ramírez, Gabriela; Simental-Mendía, Luis E; Carrera-Gracia, Manuela de la A; Quintanar-Escorza, Martha-Angélica

2017-04-01

Previous studies have indicated that vitamin E deficiency and oxidative stress affect the beta cell function. Hence, the aim of this study was to determine the association between vitamin E deficiency and oxidative status with prediabetes in apparently healthy subjects. Apparently healthy men and women aged 18-65 years were enrolled in a case-control study. Individuals with new diagnosis of prediabetes were considered as cases and compared with a control group of individuals with normal glucose tolerance. Smoking, alcohol intake, pregnancy, diabetes, kidney disease, liver disease, cardiovascular disease, malignancy, glucocorticoid treatment and consumption of lipid-lowering drugs, antioxidants and vitamin supplements were exclusion criteria. Vitamin E deficiency was defined by serum levels of α-tocopherol <11.6 μmol/L, oxidative status was assessed by total antioxidant capacity and lipid peroxidation, and prediabetes was considered by the presence of impaired fasting glucose and/or impaired glucose tolerance. A total of 148 subjects were allocated into the case (n = 74) and control (n = 74) groups. The frequency of vitamin E deficiency was higher in the case group (41.8%) compared with the control group (35.1%), p = 0.03. The logistic regression analysis adjusted by age, waist circumference and body mass index, revealed a significant association between vitamin E deficiency (OR 3.23; 95% CI: 1.34-7.79, p = 0.009), lipoperoxidation (OR 2.82; CI 95%: 1.42-5.59, p = 0.003) and total antioxidant capacity (OR 0.93; CI 95%: 0.90-0.96, p <0.001) with prediabetes. Results of the present study suggest that both vitamin E deficiency and oxidative status are associated with prediabetes in apparently healthy subjects. Copyright © 2017 IMSS. Published by Elsevier Inc. All rights reserved.

40 CFR 52.1126 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Control strategy: Sulfur oxides. 52... strategy: Sulfur oxides. (a) The revisions to the control strategy resulting from the modification to the..., which allows a relaxation of sulfur in fuel limitations under certain conditions, is approved for the...

40 CFR 52.1278 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Control strategy: Sulfur oxides and particulate matter. 52.1278 Section 52.1278 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...) Mississippi § 52.1278 Control strategy: Sulfur oxides and particulate matter. (a) In a letter dated January 30...

40 CFR 52.1126 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Control strategy: Sulfur oxides. 52... strategy: Sulfur oxides. (a) The revisions to the control strategy resulting from the modification to the..., which allows a relaxation of sulfur in fuel limitations under certain conditions, is approved for the...

40 CFR 52.1278 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Control strategy: Sulfur oxides and particulate matter. 52.1278 Section 52.1278 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...) Mississippi § 52.1278 Control strategy: Sulfur oxides and particulate matter. (a) In a letter dated January 30...

Brain-derived neurotrophic factor (BDNF) and oxidative stress in heroin-dependent male patients undergoing methadone maintenance treatment.

PubMed

Tsai, Meng-Chang; Huang, Tiao-Lai

2017-03-01

Brain-derived neurotrophic factor (BDNF) and oxidative stress may play a role in patients with heroin dependence. The aim of this study was to investigate the serum levels and activities of BDNF and oxidative stress markers, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), thiobarbituric acid reactive substances (TBARS), protein carbonyl content (PCC), and 8-hydroxy 2'-deoxyguanosine (8-OHdG), in heroin-dependent patients undergoing methadone maintenance treatment (MMT). 60 heroin-dependent male MMT patients and 30 healthy males were recruited for this study. The serum BDNF and oxidative stress markers of these subjects were measured with assay kits. Analyses of covariance (ANCOVAs) with age and body mass index adjustments indicated that the serum levels of BDNF in the MMT patients were significantly higher than those in the healthy controls (F=5.169; p=0.026). However, there were no significant differences between the heroin-dependent patients and the healthy controls in the serum levels or activities of oxidative stress markers (p>0.05). In conclusion, our results suggest that MMT increases BDNF levels in heroin-dependent patients, and that patients undergoing MMT might be in a balanced state of reduced oxidation. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Ambroxol improves lysosomal biochemistry in glucocerebrosidase mutation-linked Parkinson disease cells.

PubMed

McNeill, Alisdair; Magalhaes, Joana; Shen, Chengguo; Chau, Kai-Yin; Hughes, Derralyn; Mehta, Atul; Foltynie, Tom; Cooper, J Mark; Abramov, Andrey Y; Gegg, Matthew; Schapira, Anthony H V

2014-05-01

Gaucher disease is caused by mutations in the glucocerebrosidase gene, which encodes the lysosomal hydrolase glucosylceramidase. Patients with Gaucher disease and heterozygous glucocerebrosidase mutation carriers are at increased risk of developing Parkinson's disease. Indeed, glucocerebrosidase mutations are the most frequent risk factor for Parkinson's disease in the general population. Therefore there is an urgent need to understand the mechanisms by which glucocerebrosidase mutations predispose to neurodegeneration to facilitate development of novel treatments. To study this we generated fibroblast lines from skin biopsies of five patients with Gaucher disease and six heterozygous glucocerebrosidase mutation carriers with and without Parkinson's disease. Glucosylceramidase protein and enzyme activity levels were assayed. Oxidative stress was assayed by single cell imaging of dihydroethidium. Glucosylceramidase enzyme activity was significantly reduced in fibroblasts from patients with Gaucher disease (median 5% of controls, P = 0.0001) and heterozygous mutation carriers with (median 59% of controls, P = 0.001) and without (56% of controls, P = 0.001) Parkinson's disease compared with controls. Glucosylceramidase protein levels, assessed by western blot, were significantly reduced in fibroblasts from Gaucher disease (median glucosylceramidase levels 42% of control, P < 0.001) and heterozygous mutation carriers with (median 59% of control, P < 0.001) and without (median 68% of control, P < 0.001) Parkinson's disease. Single cell imaging of dihydroethidium demonstrated increased production of cytosolic reactive oxygen species in fibroblasts from patients with Gaucher disease (dihydroethidium oxidation rate increased by a median of 62% compared to controls, P < 0.001) and heterozygous mutation carriers with (dihydroethidium oxidation rate increased by a median of 68% compared with controls, P < 0.001) and without (dihydroethidium oxidation rate increased by a median of 70% compared with controls, P < 0.001) Parkinson's disease. We hypothesized that treatment with the molecular chaperone ambroxol hydrochloride would improve these biochemical abnormalities. Treatment with ambroxol hydrochloride increased glucosylceramidase activity in fibroblasts from healthy controls, Gaucher disease and heterozygous glucocerebrosidase mutation carriers with and without Parkinson's disease. This was associated with a significant reduction in dihydroethidium oxidation rate of ∼50% (P < 0.05) in fibroblasts from controls, Gaucher disease and heterozygous mutation carriers with and without Parkinson's disease. In conclusion, glucocerebrosidase mutations are associated with reductions in glucosylceramidase activity and evidence of oxidative stress. Ambroxol treatment significantly increases glucosylceramidase activity and reduces markers of oxidative stress in cells bearing glucocerebrosidase mutations. We propose that ambroxol hydrochloride should be further investigated as a potential treatment for Parkinson's disease.

The Effect of Agoraphobia on Oxidative Stress in Panic Disorder

PubMed Central

Karlidag, Rifat; Cumurcu, Birgul Elbozan; Turkoz, Yusuf; Kartalci, Sukru; Ozcan, A. Cemal; Erdemli, M. Erman

2013-01-01

We aimed to investigate whether agoraphobia (A) in panic disorder (PD) has any effects on oxidative and anti-oxidative parameters. We measured total antioxidant capacity (TAC), paraoxonase (PON), arylesterase (ARE) antioxidant and malondialdehyde (MDA) oxidant levels using blood samples from a total of 31 PD patients with A, 22 PD patients without A and 53 control group subjects. There was a significant difference between the TAC, PON, ARE and MDA levels of the three groups consisting of PD with A, PD without A and the control group. The two-way comparison to clarify the group creating the difference showed that the TAC, PON, and ARE antioxidants were significantly lower in the PD with A group compared to the control group while the MDA oxidant was significantly higher. There was no significant difference between the PD without A and control groups for TAC, PON, ARE and MDA levels. We clearly demonstrated that the oxidative stress and damage to the anti-oxidative mechanism are significantly higher in the PD group with A. These findings suggest that oxidative/anti-oxidative mechanisms may play a more important role on the pathogenesis of PB with A. PMID:24474979

About structural phase state of coating based on zirconium oxide formed by microplasma oxidation method

NASA Astrophysics Data System (ADS)

Gubaidulina, Tatiana A.; Sergeev, Viktor P.; Kuzmin, Oleg S.; Fedorischeva, Marina V.; Kalashnikov, Mark P.

2017-12-01

The oxide-ceramic coating based of zirconium oxide is formed by the method of microplasma oxidation. The producing modes of the oxide layers on E110 zirconium alloy are under testing. It was found that using microplasma treatment of E110 zirconium in aluminosilicate electrolyte makes possible the formation of porous oxide-ceramic coatings based on zirconium alloyed by aluminum and niobium. The study is focused on the modes how to form heat-shielding coatings with controlled porosity and minimal amount of microcracks. The structural-phase state of the coating is studied by X-ray diffraction analysis and scanning electron microscopy (SEM). It was found that the ratio of the monoclinic and tetragonal phases changes with the change occurring in the coating formation modes.

Altered mitochondrial function and oxidative stress in leukocytes of anorexia nervosa patients.

PubMed

Victor, Victor M; Rovira-Llopis, Susana; Saiz-Alarcon, Vanessa; Sangüesa, Maria C; Rojo-Bofill, Luis; Bañuls, Celia; Falcón, Rosa; Castelló, Raquel; Rojo, Luis; Rocha, Milagros; Hernández-Mijares, Antonio

2014-01-01

Anorexia nervosa is a common illness among adolescents and is characterised by oxidative stress. The effects of anorexia on mitochondrial function and redox state in leukocytes from anorexic subjects were evaluated. A multi-centre, cross-sectional case-control study was performed. Our study population consisted of 20 anorexic patients and 20 age-matched controls, all of which were Caucasian women. Anthropometric and metabolic parameters were evaluated in the study population. To assess whether anorexia nervosa affects mitochondrial function and redox state in leukocytes of anorexic patients, we measured mitochondrial oxygen consumption, membrane potential, reactive oxygen species production, glutathione levels, mitochondrial mass, and complex I and III activity in polymorphonuclear cells. Mitochondrial function was impaired in the leukocytes of the anorexic patients. This was evident in a decrease in mitochondrial O2 consumption (P<0.05), mitochondrial membrane potential (P<0.01) and GSH levels (P<0.05), and an increase in ROS production (P<0.05) with respect to control subjects. Furthermore, a reduction of mitochondrial mass was detected in leukocytes of the anorexic patients (P<0.05), while the activity of mitochondrial complex I (P<0.001), but not that of complex III, was found to be inhibited in the same population. Oxidative stress is produced in the leukocytes of anorexic patients and is closely related to mitochondrial dysfunction. Our results lead us to propose that the oxidative stress that occurs in anorexia takes place at mitochondrial complex I. Future research concerning mitochondrial dysfunction and oxidative stress should aim to determine the physiological mechanism involved in this effect and the physiological impact of anorexia.

NOVEL OXIDANT FOR ELEMENTAL MERCURY CONTROL FROM FLUE GAS

EPA Science Inventory

The primary objective of this study is to develop and test advanced noncarbonaceous solid sorbent materials suitable for removing the elemental form of mercury from power plant emissions. An efficient and cost-effective novel Hg(0) oxidant was evaluated in a lab-scale fixed-bed ...

Serum prolidase enzyme activity in obese subjects and its relationship with oxidative stress markers.

PubMed

Aslan, Mehmet; Duzenli, Ufuk; Esen, Ramazan; Soyoral, Yasemin Usul

2017-10-01

The relationship between increased serum enzyme activity of prolidase and increased rate of collagen turnover in the arterial wall has been asserted in previous studies. Collagen reflects much of the strength to the connective tissue involved in the arterial wall. Atherosclerosis is very common vessel disease and oxidative stress plays a pivotal role in the etiopathogenesis. Our objective was to examine the serum enzyme activity of prolidase and its possible relationships with oxidative stress parameters in obese subjects. Our present study was conducted 27 obese subjects and 26 age-matched healthy control subjects. The serum enzyme activity of prolidase in all study population was evaluated spectrophotometrically. Oxidative stress levels in obese subjects were analyzed with total antioxidant capacity (TAC) and total oxidant status (TOS) as well as oxidative stress index (OSI). Obese subjects have higher serum TOS and OSI indicators as well as prolidase activity than those in control subjects (for all; p<0.001). Moreover, obese subjects have lower levels of TAC than in those in healthy subjects (p<0.001). In the Pearson's correlation analysis, enzyme activity of prolidase was positively related with TOS (p<0.001, r=0.529) and OSI (p<0.001, r=0.519) as well as BMI (p<0.001, r=0.692) and inversely related with TAC (p<0.05, r=-0.405) in obese subjects. Increased serum prolidase activity and decreased antioxidant levels are likely to be a results of increased of oxidative stress levels in obese subjects. The significantly correlation between increased oxidative stress and increased prolidase activity may play a pivotal role in etiopathogenesis of atherosclerotic cardiovascular diseases in obese subjects. Copyright © 2017 Elsevier B.V. All rights reserved.

Accelerated and enhanced bone formation on novel simvastatin-loaded porous titanium oxide surfaces.

PubMed

Nyan, Myat; Hao, Jia; Miyahara, Takayuki; Noritake, Kanako; Rodriguez, Reena; Kasugai, Shohei

2014-10-01

With increasing application of dental implants in poor-quality bones, the need for implant surfaces ensuring accelerated osseointegration and enhanced peri-implant bone regeneration is increased. A study was performed to evaluate the osseointegration and bone formation on novel simvastatin-loaded porous titanium oxide surface. Titanium screws were treated by micro-arc oxidation to form porous oxide surface and 25 or 50 μg of simvastatin was loaded. The nontreated control, micro-arc oxidized, and simvastatin-loaded titanium screws were surgically implanted into the proximal tibia of 16-week-old male Wistar rats (n = 36). Peri-implant bone volume, bone-implant contact, and mineral apposition rates were measured at 2 and 4 weeks. Data were analyzed by one-way analysis of variance followed by Tukey's post hoc test. New bone was formed directly on the implant surface in the bone marrow cavity in simvastatin-loaded groups since 2 weeks. Bone-implant contact values were significantly higher in simvastatin-loaded groups than control and micro-arc oxidized groups at both time points (p < .05). Peri-implant bone volume and mineral apposition rate of simvastatin-loaded groups were significantly higher than control and micro-arc oxidized groups at 2 weeks (p < .05). These data suggested that simvastatin-loaded porous titanium oxide surface provides faster osseointegration and peri-implant bone formation and it would be potentially applicable in poor-quality bones. © 2013 Wiley Periodicals, Inc.

Influence of localized plasticity on oxidation behaviour of austenitic stainless steels under primary water reactor

NASA Astrophysics Data System (ADS)

Cissé, Sarata; Laffont, Lydia; Lafont, Marie-Christine; Tanguy, Benoit; Andrieu, Eric

2013-02-01

The sensitivity of precipitation-strengthened A286 austenitic stainless steel to stress corrosion cracking was studied by means of slow-strain-rate tests. First, alloy cold working by low cycle fatigue (LCF) was investigated. Fatigue tests under plastic strain control were performed at different strain levels (Δɛp/2 = 0.2%, 0.5%, 0.8% and 2%) to establish correlations between stress softening and the deformation microstructure resulting from the LCF tests. Deformed microstructures were identified through TEM investigations. The interaction between oxidation and localized deformation bands was also studied and it resulted that localized deformation bands are not preferential oxide growth channels. The pre-cycling of the alloy did not modify its oxidation behaviour. However, intergranular oxidation in the subsurface under the oxide layer formed after exposure to PWR primary water was shown.

Suppression of Oxidative Stress by Resveratrol After Isometric Contractions in Gastrocnemius Muscles of Aged Mice

PubMed Central

Ryan, Michael J.; Jackson, Janna R.; Hao, Yanlei; Williamson, Courtney L.; Dabkowski, Erinne R.; Hollander, John M.

2010-01-01

This study tested the hypothesis that resveratrol supplementation would lower oxidative stress in exercised muscles of aged mice. Young (3 months) and aged (27 months) C57BL/6 mice received a control or a 0.05% trans-resveratrol-supplemented diet for 10 days. After 7 days of dietary intervention, 20 maximal electrically evoked isometric contractions were obtained from the plantar flexors of one limb in anesthetized mice. Exercise was conducted for three consecutive days. Resveratrol supplementation blunted the exercise-induced increase in xanthine oxidase activity in muscles from young (25%) and aged (53%) mice. Resveratrol lowered H2O2 levels in control (13%) and exercised (38%) muscles from aged animals, reduced Nox4 protein in both control and exercised muscles of young (30%) and aged mice (40%), and increased the ratio of reduced glutathione to oxidized glutathione in exercised muscles from young (38%) and aged (135%) mice. Resveratrol prevented the increase in lipid oxidation, increased catalase activity, and increased MnSOD activity in exercised muscles from aged mice. These data show that dietary resveratrol suppresses muscle indicators of oxidative stress in response to isometric contractions in aged mice. PMID:20507922

Increased Serum Oxidative Stress Markers in Women with Uterine Leiomyoma

PubMed Central

Santulli, Pietro; Borghese, Bruno; Lemaréchal, Herve; Leconte, Mahaut; Millischer, Anne-Elodie; Batteux, Frédéric

2013-01-01

Background Uterine leiomyomas (fibroids) are the most common gynaecological benign tumors in premenopausal women. Evidences support the role of oxidative stress in the development of uterine leiomyoma. We have analysed oxidative stress markers (thiols, advanced oxidized protein products (AOPP), protein carbonyls and nitrates/nitrites) in preoperative sera from women with histologically proven uterine leiomyoma. Methodology/Principal Findings We conducted a laboratory study in a tertiary-care university hospital. Fifty-nine women with histologically proven uterine leiomyoma and ninety-two leiomyoma-free control women have been enrolled in this study. Complete surgical exploration of the abdominopelvic cavity was performed in each patient. Preoperative serum samples were obtained from all study participants to assay serum thiols, AOPP, protein carbonyls and nitrates/nitrites. Concentrations of serum protein carbonyl groups and AOPP were higher in leiomyoma patients than in the control group (p=0.005 and p<0.001, respectively). By contrast, serum thiol levels were lower in leiomyoma patients (p<0.001). We found positive correlations between serum AOPP concentrations and total fibroids weight (r=0.339; p=0.028), serum AOPP and serum protein carbonyls with duration of infertility (r=0.762; p=0.006 and r=0.683; p=0.021, respectively). Conclusions/Significance This study, for the first time, reveals a significant increase of protein oxidative stress status and reduced antioxidant capacity in sera from women with uterine leiomyoma. PMID:23951284

A Role of Fluoride on Free Radical Generation and Oxidative Stress in BV-2 Microglia Cells

PubMed Central

Shuhua, Xi; Ziyou, Liu; Ling, Yan; Fei, Wang; Sun, Guifan

2012-01-01

The generation of ROS and lipid peroxidation has been considered to play an important role in the pathogenesis of chronic fluoride toxicity. In the present study, we observed that fluoride activated BV-2 microglia cell line by observing OX-42 expression in immunocytochemistry. Intracellular superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), reactive oxygen species (ROS), superoxide anions (O2 ∙−), nitric oxide synthase (NOS), nitrotyrosine (NT) and nitric oxide (NO), NOS in cell medium were determined for oxidative stress assessment. Our study found that NaF of concentration from 5 to 20 mg/L can stimuli BV-2 cells to change into activated microglia displaying upregulated OX-42 expression. SOD activities significantly decreased in fluoride-treated BV-2 cells as compared with control, and MDA concentrations and contents of ROS and O2 ∙− increased in NaF-treated cells. Activities of NOS in cells and medium significantly increased with fluoride concentrations in a dose-dependent manner. NT concentrations also increased significantly in 10 and 50 mg/L NaF-treated cells compared with the control cells. Our present study demonstrated that toxic effects of fluoride on the central nervous system possibly partly ascribed to activiting of microglia, which enhanced oxidative stress induced by ROS and reactive nitrogen species. PMID:22933830

Application of microwave energy in the control of DPM, oxides of nitrogen and VOC emissions

NASA Astrophysics Data System (ADS)

Pallavkar, Sameer M.

The emissions of DPM (diesel particulate matter), NOx (oxides of nitrogen), and toxic VOCs (volatile organic compounds) from diesel engine exhaust gases and other sources such as chemical process industry and manufacturing industry have been a great environmental and health concern. Most control technologies for these emissions require elevated temperatures. The use of microwave energy as a source of heat energy, however, has not been fully explored. In this study, the microwave energy was used as the energy source in three separate emission control processes, namely, the regeneration of diesel particulate filter (DPF) for DPM control, the NOx reduction using a platinum catalyst, and the VOC destruction involving a ceramic based material. The study has demonstrated that microwave heating is an effective method in providing heat for the studied processes. The control efficiencies associated with the microwave-assisted processes have been observed to be high and acceptable. Further research, however, is required for the commercial use of these technologies.

Acute effects of ingestion of black and green tea on lipoprotein oxidation.

PubMed

Hodgson, J M; Puddey, I B; Croft, K D; Burke, V; Mori, T A; Caccetta, R A; Beilin, L J

2000-05-01

Tea has been associated with a reduced risk of cardiovascular disease. One proposed mechanism of this risk reduction involves inhibition of lipoprotein oxidation in vivo by antioxidant polyphenolic compounds derived from tea. However, controlled interventions uniformly failed to show that ingestion of tea can inhibit LDL oxidation ex vivo. The absence of effects in previous studies may be due to the isolation of LDL particles from polyphenolic compounds that are present in the aqueous phase of serum. The objective of this study was to examine the acute effects of ingestion of black and green tea on ex vivo Cu(2+)-induced lipoprotein oxidation without prior isolation of lipoproteins from serum. The acute effects of 4 hot drinks-green tea and black tea (each at a dose equivalent to 4 standard cups), water matched to the teas for caffeine content, and water-were assessed in 20 healthy men by using a Latin-square design. The lag time to lipoprotein diene formation, slope of the propagation phase of the oxidation curve, and area under the oxidation curve were calculated. Urinary concentrations of 4-O-methylgallic acid were used as a marker of uptake and metabolism of polyphenolic compounds from tea. Significant increases in urinary 4-O-methylgallic acid for black and green tea (P < 0. 0001) were observed. Caffeine did not significantly influence lipoprotein oxidation. Compared with the water control, there was a greater lag time for black tea (5.4 +/- 2.9 min; P = 0.05) that was of borderline significance and a similar trend for green tea (4.4 +/- 2.8 min; P = 0.17). Slope and area under the oxidation curve were not altered. Black tea has a mild acute effect on ex vivo lipoprotein oxidation in human serum. 2000;71:-7.

40 CFR 52.2033 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Sulfur oxides. 52.2033 Section 52.2033 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... strategy: Sulfur oxides. (a) The revision to the control strategy resulting from the modification to the...

40 CFR 52.2033 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 5 2013-07-01 2013-07-01 false Control strategy: Sulfur oxides. 52.2033 Section 52.2033 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... strategy: Sulfur oxides. (a) The revision to the control strategy resulting from the modification to the...

40 CFR 52.2033 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Control strategy: Sulfur oxides. 52.2033 Section 52.2033 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... strategy: Sulfur oxides. (a) The revision to the control strategy resulting from the modification to the...

Occupational exposure to asphalt fume can cause oxidative DNA damage among road paving workers.

PubMed

Bal, Ceylan; Ağış, Erol R; Büyükşekerci, Murat; Gündüzöz, Meşide; Tutkun, Lütfiye; Yılmaz, Ömer H

2018-06-01

We designed the present study to determine the effect of occupational exposure to asphalt fumes on oxidative status and DNA damage in road paving workers. Sixty road paving workers exposed to asphalt fumes and forty non-exposed control subjects were recruited. Occupational exposure to PAHs was assessed by urinary 1-hydroxypyrene (1-OHP) excretion. Serum thiol disulfide homeostasis (TDH), total oxidant status (TOS) and total antioxidant status (TAS) and urinary 8-hydro-deoxyguanosine (8-OH-dG) level were evaluated by automated colourimetric method. The urinary concentrations of 1-OHP and 8-OH-dG were significantly higher in the exposed group than in the control group (P < 0.001). Disulfide/thiol ratio, TOS, and TAS were also significantly higher for the asphalt workers. A positive correlation existed between urinary 1-OHP and 8-OH-dG, TOS and TAS. Study results indicate that exposure to PAHs induces oxidative stress and causes genotoxic effects in asphalt workers. © 2018 Wiley Periodicals, Inc.

In Situ Probing and Synthetic Control of Cationic Ordering in Ni-Rich Layered Oxide Cathodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Jianqing; Zhang, Wei; Huq, Ashfia

Ni-rich layered oxides (LiNi 1-xM xO 2; M=Co, Mn, …) are appealing alternatives to conventional LiCoO 2 as cathodes in Li-ion batteries for automobile and other large-scale applications due to their high theoretical capacity and low cost. However, preparing stoichiometric LiNi 1-xM xO 2 with ordered layer structure and high reversible capacity, has proven difficult due to Ni 2+/Li + cation mixing in octahedral sites. Herein, we report on in-situ studies of synthesis reactions and the associated structural ordering in preparing LiNiO 2 and the Co-substituted variant, LiNi 0.8Co 0.2O 2, thereby gaining insights into synthetic control of the structuremore » and electrochemical properties of Ni-rich layered oxides. Results from this study indicate a direct transformation of the intermediate from the rock salt structure into hexagonal phase, and during the process, Co substitution facilities the nucleation of a Co-rich layered phase at low temperatures and subsequent growth and stabilization of solid solution Li(Ni, Co)O 2 upon heat treatment in a highly oxidation environment. Optimal conditions were identified from the in-situ studies and utilized in obtaining stoichiometric LiNi 0.8Co 0.2O 2 that exhibits high capacity of about 200 mAh/g with excellent retention. The findings shed light on designing Ni-rich layered oxide cathodes with enhanced electrochemical properties through synthetic control of the structural ordering in the materials.« less

[Effects of parabolic flight on redox status in SH-SY5Y cells].

PubMed

Bi, Lei; Qu, Li-Na; Huang, Zeng-Ming; Wang, Chun-Yan; Li, Qi; Tan, Ying-Jun; Li, Ying-Hui

2009-10-25

Space flight is known to produce a number of neurological disturbances. The etiology is unknown, but it may involve increased oxidative stress. A line of experimental evidence indicates that space flight may disrupt antioxidant defense system and result in increased oxidative stress. In vitro studies found that abundant of NO was produced in rat pheochromocytoma (PC12) cells, SHSY5Y neuroblastoma cells, and protein nitration was increased in PC12 cells within a simulated microgravity rotating wall bioreactor high aspect ratio vessel system or clinostat system. In the present study, we observed the change of redox status in SH-SY5Y cells after parabolic flight, and studied the effects of key redox molecule, thioredoxin (TRX), during the altered gravity. SH-SY5Y cells were divided into four groups: control cells, control cells transfected with TRX, flight cells and flight cells transfected with TRX. The expression levels of 3-nitrotyrosine (3-NT), inducible nitric oxide synthase (iNOS), TRX and thioredoxin reductase (TRXR) were observed by immunocytochemical method. It was shown that after parabolic flight, the staining of 3-NT and TRX were enhanced, while the expression level of TRXR was down-regulated compared with control. As for flight cells transfected with TRX, the staining of 3-NT and iNOS were weakened compared with flight cells. These results obtained suggest that altered gravity may increase protein nitration, down-regulate TRXR and elicit oxidative stress in SH-SY5Y cells, while TRX transfection could partly protect cells against oxidative stress induced by parabolic flight.

In Situ Probing and Synthetic Control of Cationic Ordering in Ni-Rich Layered Oxide Cathodes

DOE PAGES

Zhao, Jianqing; Zhang, Wei; Huq, Ashfia; ...

2016-10-17

Ni-rich layered oxides (LiNi 1-xM xO 2; M=Co, Mn, …) are appealing alternatives to conventional LiCoO 2 as cathodes in Li-ion batteries for automobile and other large-scale applications due to their high theoretical capacity and low cost. However, preparing stoichiometric LiNi 1-xM xO 2 with ordered layer structure and high reversible capacity, has proven difficult due to Ni 2+/Li + cation mixing in octahedral sites. Herein, we report on in-situ studies of synthesis reactions and the associated structural ordering in preparing LiNiO 2 and the Co-substituted variant, LiNi 0.8Co 0.2O 2, thereby gaining insights into synthetic control of the structuremore » and electrochemical properties of Ni-rich layered oxides. Results from this study indicate a direct transformation of the intermediate from the rock salt structure into hexagonal phase, and during the process, Co substitution facilities the nucleation of a Co-rich layered phase at low temperatures and subsequent growth and stabilization of solid solution Li(Ni, Co)O 2 upon heat treatment in a highly oxidation environment. Optimal conditions were identified from the in-situ studies and utilized in obtaining stoichiometric LiNi 0.8Co 0.2O 2 that exhibits high capacity of about 200 mAh/g with excellent retention. The findings shed light on designing Ni-rich layered oxide cathodes with enhanced electrochemical properties through synthetic control of the structural ordering in the materials.« less

40 CFR 52.2731 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2014 CFR

2014-07-01

...: Sulfur oxides. 52.2731 Section 52.2731 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Rico § 52.2731 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of... the national standards for sulfur oxides in the areas of Aguirre, Barceloneta, Trujillo Alto-Dorado...

40 CFR 52.2731 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2013 CFR

2013-07-01

...: Sulfur oxides. 52.2731 Section 52.2731 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Rico § 52.2731 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of... the national standards for sulfur oxides in the areas of Aguirre, Barceloneta, Trujillo Alto-Dorado...

40 CFR 52.2731 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2011 CFR

2011-07-01

...: Sulfur oxides. 52.2731 Section 52.2731 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Rico § 52.2731 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of... the national standards for sulfur oxides in the areas of Aguirre, Barceloneta, Trujillo Alto-Dorado...

40 CFR 52.2731 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2012 CFR

2012-07-01

...: Sulfur oxides. 52.2731 Section 52.2731 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Rico § 52.2731 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of... the national standards for sulfur oxides in the areas of Aguirre, Barceloneta, Trujillo Alto-Dorado...

40 CFR 52.2731 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2010 CFR

2010-07-01

...: Sulfur oxides. 52.2731 Section 52.2731 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Rico § 52.2731 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of... the national standards for sulfur oxides in the areas of Aguirre, Barceloneta, Trujillo Alto-Dorado...

Protective effects of a grape-supplemented diet in a mouse model of retinal degeneration.

PubMed

Patel, Amit K; Davis, Ashley; Rodriguez, Maria Esperanza; Agron, Samantha; Hackam, Abigail S

2016-03-01

Retinal degenerations are a class of devastating blinding diseases that are characterized by photoreceptor dysfunction and death. In this study, we tested whether grape consumption, in the form of freeze-dried grape powder (FDGP), improves photoreceptor survival in a mouse model of retinal degeneration. Retinal degeneration was induced in mice by acute oxidative stress using subretinal injection of paraquat. The grape-supplemented diet was made by formulating base mouse chow with FDGP, corresponding to three daily human servings of grapes, and a control diet was formulated with equivalent sugar composition as FDGP (0.68% glucose-0.68% fructose mixture). Mice were placed on the diets at weaning for 5 wk before oxidative stress injury until analysis at 2 wk post-injection. Retinal function was measured using electroretinography, thickness of the photoreceptor layer was measured using optical coherence tomography, and rows of photoreceptor nuclei were counted on histologic sections. In mice fed the control diet, oxidative stress significantly reduced photoreceptor layer thickness and photoreceptor numbers. In contrast, retinal thickness and photoreceptor numbers were not reduced by oxidative stress in mice on the grape-supplemented diet, indicating significantly higher photoreceptor survival after injury than mice on the control diet. Furthermore, mice on the grape diet showed preservation of retinal function after oxidative stress injury compared with mice on the control diet. A diet supplemented with grapes rescued retinal structure and function in an oxidative stress-induced mouse model of retinal degeneration, which demonstrates the beneficial effect of grapes on photoreceptors. Copyright © 2016 Elsevier Inc. All rights reserved.

The relationship between potency of oxidative stress and severity of dilated cardiomyopathy.

PubMed

Demirbag, Recep; Yilmaz, Remzi; Erel, Ozcan; Gultekin, Unal; Asci, Durmus; Elbasan, Zafer

2005-08-01

It has been suggested that oxidative stress may have a role in the etiopathogenesis of congestive heart failure. To investigate and compare the oxidative-antioxidative status and oxidative stress index (OSI) of patients with idiopathic dilated cardiomyopathy (IDC) with those of healthy volunteers, and to determine the relationship between total antioxidant capacity (TAC) and ejection fraction (EF). Twenty-eight patients with IDC and 24 control subjects were enrolled in the study. Antioxidative status was evaluated by measuring the TAC and the vitamin C and thiol levels in the plasma. Oxidative status was evaluated by measuring the total peroxide level. The per cent ratio of TAC to total peroxide level was accepted as the OSI. EF was measured using Simpson's method. TAC and vitamin C and thiol levels of plasma were found to be significantly lower in patients with IDC than in control subjects (P < 0.001). In contrast, total peroxide levels and OSIs were significantly higher in patients with IDC than in control subjects (P = 0.002 and P = 0.002, respectively). An important positive correlation was found between TAC and EF (r = 0.772; P < 0.001). On the other hand, significant negative correlations were found between EF and OSI and between EF and total peroxide levels in patients. Oxidants are increased and antioxidants are decreased in patients with IDC; as a result, the oxidative-antioxidative balance is shifted to the oxidative side. There is a significant correlation between the potency of oxidative stress and the severity of IDC. It is believed that supplementation of antioxidants in the treatment of IDC may be helpful to these patients.

Analysis of Oxidative Stress Status, Catalase and Catechol-O-Methyltransferase Polymorphisms in Egyptian Vitiligo Patients

PubMed Central

Mehaney, Dina A.; Darwish, Hebatallah A.; Hegazy, Rehab A.; Nooh, Mohammed M.; Tawdy, Amira M.; Gawdat, Heba I.; El-Sawalhi, Maha M.

2014-01-01

Vitiligo is the most common depigmentation disorder of the skin. Oxidative stress is implicated as one of the probable events involved in vitiligo pathogenesis possibly contributing to melanocyte destruction. Evidence indicates that certain genes including those involved in oxidative stress and melanin synthesis are crucial for development of vitiligo. This study evaluates the oxidative stress status, the role of catalase (CAT) and catechol-O-Methyltransferase (COMT) gene polymorphisms in the etiology of generalized vitiligo in Egyptians. Total antioxidant capacity (TAC) and malondialdehyde (MDA) levels as well as CAT exon 9 T/C and COMT 158 G/A polymorphisms were determined in 89 patients and 90 age and sex-matched controls. Our results showed significantly lower TAC along with higher MDA levels in vitiligo patients compared with controls. Meanwhile, genotype and allele distributions of CAT and COMT polymorphisms in cases were not significantly different from those of controls. Moreover, we found no association between both polymorphisms and vitiligo susceptibility. In conclusion, the enhanced oxidative stress with the lack of association between CAT and COMT polymorphisms and susceptibility to vitiligo in our patients suggest that mutations in other genes related to the oxidative pathway might contribute to the etiology of generalized vitiligo in Egyptian population. PMID:24915010

Theoretical studies on the control of oxidative phosphorylation in muscle mitochondria: application to mitochondrial deficiencies.

PubMed

Korzeniewski, B; Mazat, J P

1996-10-01

1. The dynamic model of oxidative phosphorylation developed previously for rat liver mitochondria incubated with succinate was adapted for muscle mitochondria respiring on pyruvate. We introduced the following changes considering: (1) a higher external ATP/ADP ratio and an ATP/ADP carrier less displaced from equilibrium; (2) a substrate dehydrogenation more sensitive to the NADH/NAD+ ratio; and (3) the respiratory chain, ATP synthase and phosphate carrier being more displaced from equilibrium. The experimental flux control coefficients already determined in state 3 for respiratory rate and ATP synthesis were used to adjust some parameters. This new oxidative phosphorylation model enabled us to simulate the whole titration curves obtained experimentally in state 3. These curves, which mimic the effect of mitochondrial complex deficiencies on oxidative phosphorylation, show a threshold effect, which is reproduced by the model. 2. the model was also used to simulate other physiological conditions such as (i) state 3.5, conditions in-between state 4 and state 3; and (ii) hypoxic conditions. In both cases a profound change in the pattern of the control coefficients was shown. 3. This model was thus found useful in investigating a variety of new conditions, the most interesting of which can then be experimentally studied.

Obesity induced alterations in redox homeostasis and oxidative stress are present from an early age.

PubMed

Lechuga-Sancho, Alfonso M; Gallego-Andujar, David; Ruiz-Ocaña, Pablo; Visiedo, Francisco M; Saez-Benito, Ana; Schwarz, Mónica; Segundo, Carmen; Mateos, Rosa M

2018-01-01

Oxidative stress and inflammation have been postulated as underlying mechanisms for the development of obesity-related insulin resistance. This association however, remains elusive especially in childhood. We sought to investigate this relation by measuring oxidative stress and antioxidant response biomarkers, before and during an oral glucose tolerance test (OGTT), in different biological samples from obese children. 24 children were recruited for the study, (18 obese and 6 controls). After OGTT, the obese group was subdivided in two, according to whether or not carbohydrate metabolic impairment (Ob.IR+, Ob.IR-; respectively) was found. Different biomarkers were analyzed after fasting (T = 0) and during an OGTT (T = 60 and 120 min). Lipoperoxides were measured in plasma, erythrocytes, and urine; while advanced glycation end products were determined in plasma, and redox status (GSH/GSSG ratio) in erythrocytes. We found marked differences in the characterization of the oxidative status in urine and erythrocytes, and in the dynamics of the antioxidant response during OGTT. Specifically, Ob.IR+ children show increased oxidative stress, deficient antioxidant response and a significant imbalance in redox status, in comparison to controls and Ob.IR- children. Obese children with insulin resistance show increased levels of oxidative stress biomarkers, and a stunted antioxidant response to an OGTT leading to increased oxidative stress after a single glucose load, as detected in erythrocytes, but not in plasma. We propose erythrocytes as sensors of early and acute changes in oxidative stress associated with insulin resistance in childhood obesity. This is a pilot study, performed with a limited sample size, so data should be interpreted with caution until reproduced.

Evaluating OSHA's ethylene oxide standard: exposure determinants in Massachusetts hospitals.

PubMed Central

LaMontagne, A D; Kelsey, K T

2001-01-01

OBJECTIVES: This study sought to identify determinants of workplace exposures to ethylene oxide to assess the effect of the Occupational Safety and Health Administration's (OSHA's) 1984 ethylene oxide standard. METHODS: An in-depth survey of all hospitals in Massachusetts that used ethylene oxide from 1990 through 1992 (96% participation, N = 90) was conducted. Three types of exposure events were modeled with logistic regression: exceeding the 8-hour action level, exceeding the 15-minute excursion limit, and worker exposures during unmeasured accidental releases. Covariates were drawn from data representing an ecologic framework including direct and indirect potential exposure determinants. RESULTS: After adjustment for frequencies of ethylene oxide use and exposure monitoring, a significant inverse relation was observed between exceeding the action level and the use of combined sterilizer-aerators, an engineering control technology developed after the passage of the OSHA standard. Conversely, the use of positive-pressure sterilizers that employ ethylene oxide gas mixtures was strongly related to both exceeding the excursion limit and the occurrence of accidental releases. CONCLUSIONS: These findings provide evidence of a positive effect of OSHA's ethylene oxide standard and specific targets for future prevention and control efforts. PMID:11236406

X-ray analyses of thermally grown and reactively sputtered tantalum oxide films on NiTi alloy

NASA Astrophysics Data System (ADS)

McNamara, Karrina; Tofail, Syed A. M.; Conroy, Derek; Butler, James; Gandhi, Abbasi A.; Redington, Wynette

2012-08-01

Sputter deposition of tantalum (Ta) on the surface of NiTi alloy is expected to improve the alloy's corrosion resistance and biocompatibility. Tantalum is a well-known biomaterial which is not affected by body fluids and is not irritating to human tissue. Here we compare the oxidation chemistry crystal structure evolution of tantalum oxide films grown on NiTi by reactive O2 sputtering and by thermal oxidation of sputter deposited Ta films. The effect of sputtering parameters and post-sputtering treatments on the morphology, oxidation state and crystal structure of the tantalum oxide layer have been investigated by field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The study has found that it may be better to avoid oxidation at and above 600 °C. The study establishes that reactive sputtering in presence of low oxygen mixture yields thicker film with better control of the film quality except that the surface oxidation state of Ta is slightly lower.

Urinary level of nickel and acute leukaemia in Chinese children.

PubMed

Yang, Y; Jin, X M; Yan, C H; Tian, Y; Tang, J Y; Shen, X M

2008-10-01

The 8-hydroxy-2'-deoxyguanosine (8-OHdG), an oxidized nucleoside of DNA, not only is a widely used biomarker for the measurement of endogenous oxidative DNA damage but might also be a risk factor for many diseases including cancer. Metal exposure may play an important role in oxidative DNA damage among children. However, few studies on urinary 8-OHdG and metals have been conducted in children with acute leukemia. In the present study, urinary Ni and 8-OHdG were examined in 116 children with acute leukaemia (94 acute lymphoid leukaemia [ALL] and 22 acute myeloid leukaemia [AML]) and 51 healthy child controls. Our result showed that urinary Ni in acute leukaemia patients (ALL: 68.40 +/- 133.98, AML: 41.48 +/- 76.31 ng/mg creatinine) was significantly higher than that in controls (62.47 +/- 124.90 vs 17.63 +/- 46.17 ng/mg creatinine, P < 0.05). Similarly, the pretherapy level of urinary 8-OHdG in patients (ALL: 11.83 +/- 16.23, AML: 12.36 +/- 11.36 ng/mg creatinine) was significantly elevated compared with controls (11.92 +/- 15.42 vs 4.03 +/- 4.70 ng/mg creatinine, P < 0.05). Moreover, urinary 8-OHdG and urinary Ni showed a weak but significant association with increased risk of childhood leukaemia. The present study suggests that Ni may be an etiologic factor for childhood acute leukaemia by oxidative DNA damage.

Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

NASA Technical Reports Server (NTRS)

Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

2001-01-01

A process for producing polycrystalline silicon carbide by heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

NASA Technical Reports Server (NTRS)

Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

2000-01-01

A process for producing polycrystalline silicon carbide includes heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

Generation of reactive oxygen species and oxidative stress in Escherichia coli and Staphylococcus aureus by a novel semiconductor catalyst

NASA Astrophysics Data System (ADS)

Chow, K. L.; Mak, N. K.; Wong, M. H.; Zhou, X. F.; Liang, Y.

2011-03-01

The objective of this study was to investigate antimicrobial mechanisms of a new catalytic material (charge transfer auto oxidation-reduction type catalyst, CT catalyst) that may have great potential for application in water/wastewater treatment. Generation of reactive oxygen species (ROS) in bacteria-free solution, induction of ROS and oxidative damage in bacteria (including E. coli and S. aureus) were examined for the CT catalyst. The results showed that significantly higher ( p < 0.05, via t-test) amount of hydroxyl radicals was generated by the CT catalyst compared with the control, particularly after 6 h of contact time that more than twice of the amount of the control was produced. The generation of ROS in the bacteria was greater under higher pH and temperature levels, which closely related with the oxidative damage in cells. The results indicated that CT catalyst induced oxidative damage in the bacteria might serve as an important mechanism interpreting the anti-microbial function of the CT catalyst.

Molecular analysis of erection regulatory factors in sickle cell disease associated priapism in the human penis.

PubMed

Lagoda, Gwen; Sezen, Sena F; Cabrini, Marcelo R; Musicki, Biljana; Burnett, Arthur L

2013-02-01

Priapism is a vasculopathy that occurs in approximately 40% of patients with sickle cell disease. Mouse models suggest that dysregulated nitric oxide synthase and RhoA/ROCK signaling as well as increased oxidative stress may contribute to the mechanisms of sickle cell disease associated priapism. We examined changes in the protein expression of nitric oxide synthase and ROCK signaling pathways, and a source of oxidative stress, NADPH oxidase, in penile erectile tissue from patients with a priapism history etiologically related and unrelated to sickle cell disease. Human penile erectile tissue was obtained from 5 patients with sickle cell disease associated priapism and from 6 with priapism of other etiologies during nonemergent penile prosthesis surgery for erectile dysfunction or priapism management and urethroplasty. Tissue was also obtained from 5 control patients without a priapism history during penectomy for penile cancer. Samples were collected, immediately placed in cold buffer and then frozen in liquid nitrogen. The expression of phosphodiesterase 5, endothelial nitric oxide synthase, neuronal nitric oxide synthase, inducible nitric oxide synthase, RhoA, ROCK1, ROCK2, p47(phox), p67(phox), gp91(phox) and β-actin were determined by Western blot analysis. Nitric oxide was measured using the Griess reaction. In the sickle cell disease group phosphodiesterase 5 (p <0.05), endothelial nitric oxide synthase (p <0.01) and RhoA (p <0.01) expression was significantly decreased, while gp91(phox) expression (p <0.05) was significantly increased compared to control values. In the nonsickle cell disease group endothelial nitric oxide synthase, ROCK1 and p47(phox) expression (each p <0.05) was significantly decreased compared to control values. Total nitric oxide levels were not significantly different between the study groups. Mechanisms of sickle cell disease associated priapism in the human penis may involve dysfunctional nitric oxide synthase and ROCK signaling, and increased oxidative stress associated with NADPH oxidase mediated signaling. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Effects of computer monitor-emitted radiation on oxidant/antioxidant balance in cornea and lens from rats

PubMed Central

Namuslu, Mehmet; Devrim, Erdinç; Durak, İlker

2009-01-01

Purpose This study aims to investigate the possible effects of computer monitor-emitted radiation on the oxidant/antioxidant balance in corneal and lens tissues and to observe any protective effects of vitamin C (vit C). Methods Four groups (PC monitor, PC monitor plus vitamin C, vitamin C, and control) each consisting of ten Wistar rats were studied. The study lasted for three weeks. Vitamin C was administered in oral doses of 250 mg/kg/day. The computer and computer plus vitamin C groups were exposed to computer monitors while the other groups were not. Malondialdehyde (MDA) levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities were measured in corneal and lens tissues of the rats. Results In corneal tissue, MDA levels and CAT activity were found to increase in the computer group compared with the control group. In the computer plus vitamin C group, MDA level, SOD, and GSH-Px activities were higher and CAT activity lower than those in the computer and control groups. Regarding lens tissue, in the computer group, MDA levels and GSH-Px activity were found to increase, as compared to the control and computer plus vitamin C groups, and SOD activity was higher than that of the control group. In the computer plus vitamin C group, SOD activity was found to be higher and CAT activity to be lower than those in the control group. Conclusion The results of this study suggest that computer-monitor radiation leads to oxidative stress in the corneal and lens tissues, and that vitamin C may prevent oxidative effects in the lens. PMID:19960068

Optical and electrical studies of cerium mixed oxides

NASA Astrophysics Data System (ADS)

Sherly, T. R.; Raveendran, R.

2014-10-01

The fast development in nanotechnology makes enthusiastic interest in developing nanomaterials having tailor made properties. Cerium mixed oxide materials have received great attention due to their UV absorption property, high reactivity, stability at high temperature, good electrical property etc and these materials find wide applications in solid oxide fuel cells, solar control films, cosmetics, display units, gas sensors etc. In this study cerium mixed oxide compounds were prepared by co-precipitation method. All the samples were doped with Zn (II) and Fe (II). Preliminary characterizations such as XRD, SEM / EDS, TEM were done. UV - Vis, Diffuse reflectance, PL, FT-IR, Raman and ac conductivity studies of the samples were performed.

INDUCTION OF NITRIC OXIDE SYNTHASE AND ASSOCIATED TOXICITY IN LIVERS OF HARDHEAD CATFISH, ARIUS FELIS, FROM CONTROL AND EPIZOOTIC SITES

EPA Science Inventory

Earlier work with a live channel catfish (Ictalurus punctatus) pathogen, Edwardsiella ictaluri, demonstrated the induction of nitric oxide synthase (NOS) in the head kidney, paralleling enteric septicemia (Hawke et al. 1981; Schoor and Plumb 1994). However, another study exposing...

Association of Oxidative Stress and Obesity with Insulin Resistance in Type 2 Diabetes Mellitus.

PubMed

Das, P; Biswas, S; Mukherjee, S; Bandyopadhyay, S K

2016-01-01

Oxidative stress occurs due to delicate imbalance between pro-oxidant and anti oxidant forces in our system. It has been found to be associated with many morbidities but its association with obesity and insulin resistance is still controversial. Here in our study we examined 167 patients of recent onset type 2 diabetes mellitus and 60 age sex matched non-diabetic control. Body Mass Index (BMI), abdominal circumference, fasting blood glucose, serum insulin and plasma Malondealdehyde (MDA, marker for oxidative stress) were measured in them. On the basis of BMI, subjects were divided into obese (BMI≥25) and non obese (BMI<25) groups. Insulin resistance scores were calculated by Homeostatic Model Assessment-Insulin Resistance (HOMA-IR) method. Physical parameters (BMI, abdominal circumference) as well as levels of insulin and MDA were found to be significantly higher in subjects with diabetes than their non diabetic controls. The said parameters also showed significant difference in obese and non-obese sub groups. Insulin resistance score showed positive correlation with BMI, abdominal circumference, and plasma MDA, strength of association being highest with abdominal circumference. Plasma MDA was found to have positive correlation with physical parameters. Study concludes that, obesity mainly central type may predispose to insulin resistance and oxidative stress may be a crucial factor in its pathogenesis. Thus, oxidative stress may be the connecting link between obesity and type 2 diabetes mellitus, two on going global epidemics.

UCP1 and UCP3 Expression Is Associated with Lipid and Carbohydrate Oxidation and Body Composition

PubMed Central

Oliveira, Bruno A. P.; Pinhel, Marcela A. S.; Nicoletti, Carolina F.; Oliveira, Cristiana C.; Quinhoneiro, Driele C. G.; Noronha, Natália Y.; Marchini, Júlio S.; Marchry, Ana J.; Junior, Wilson S.; Nonino, Carla B.

2016-01-01

Background/Objective Uncoupling proteins (UCPs) are located in the inner membrane of mitochondria. These proteins participate in thermogenesis and energy expenditure. This study aimed to evaluate how UCP1 and UCP3 expression influences substrate oxidation and elicits possible changes in body composition in patients submitted to bariatric surgery. Subjects/Methods This is a longitudinal study comprising 13 women with obesity grade III that underwent bariatric surgery and 10 healthy weight individuals (control group). Body composition was assessed by bioelectrical impedance. Carbohydrate and fat oxidation was determined by indirect calorimetry. Subcutaneous adipose tissue was collected for gene expression analysis. QPCR was used to evaluate UCP1 and UCP3 expression. Results Obese patients and the control group differed significantly in terms of lipid and carbohydrate oxidation. Six months after bariatric surgery, the differences disappeared. Lipid oxidation correlated with the percentage of fat mass in the postoperative period. Multiple linear regression analysis showed that the UCP1 and UCP3 genes contributed to lipid and carbohydrate oxidation. Additionally, UCP3 expression was associated with BMI, percentage of lean body mass, and percentage of mass in the postoperative period. Conclusions UCP1 and UCP3 expression is associated with lipid and carbohydrate oxidation in patients submitted to bariatric surgery. In addition, UCP3 participates in body composition modulation six months postoperatively. PMID:26959981

Oxidation of phenolic acid derivatives by soil and its relevance to allelopathic activity.

PubMed

Ohno, T

2001-01-01

Previous studies have suggested that phenolic acids from legume green manures may contribute to weed control through allelopathy. The objectives of this study were to investigate the oxidation reactions of phenolic acids in soil and to determine the subsequent effects of oxidation upon phytotoxicity. Soils were reacted for 18 h with 0.25 mmol L(-1) benzoic and cinnamic acid derivative solutions and Mn release from the suspension was used as a marker for phenolic acid oxidation. The extent of oxidation in soil suspensions was in the order of 3,4dihydroxy- > 4-hydroxy-3-methoxy- > 4-hydroxy-approximately 2-hydroxy-substituted benzoic and cinnamic acids. The same ranking was observed for cyclic voltammetry peak currents of the cinnamic acid derivatives. This suggests that the oxidation of phenolic acids is controlled by the electron transfer step from the sorbed phenolic acid to the metal oxide. A bioassay experiment showed that the 4-hydroxy-, 4-hydroxy-3-methoxy-, and 3,4-dihydroxy-substituted cinnamic acids were bioactive at 0.25 mmol L(-1) concentration. Reaction with soil for 18 h resulted in the elimination of bioactivity of these three cinnamic acids at the 5% significance level. The oxidative reactivity of phenolic acids may limit the potential of allelopathy as a component of an integrated weed management system. However, the initial phytotoxicity after soil incorporation may coincide with the early, critical stage of weed emergence and establishment, so that allelopathic phenolic acids may still play a role in weed management despite their reactivity in soil systems.

Randomized Controlled Trial Comparing Collagen/Oxidized Regenerated Cellulose/Silver to Standard of Care in the Management of Venous Leg Ulcers.

PubMed

Cullen, Breda M; Serena, Thomas E; Gibson, Molly C; Snyder, Robert J; Hanft, Jason R; Yaakov, Raphael A

2017-10-01

To assess healing outcomes in venous leg ulcers (VLUs) treated with a combination of collagen, oxidized regenerated cellulose, and silver in conjunction with standard of care (SOC; intervention group) compared with SOC alone (control group). Standard of care included ADAPTIC nonadhering dressing (Acelity, San Antonio, Texas) and compression. Randomized controlled trial that followed patients in 3 US facilities for 12 weeks or until complete healing. Forty-nine patients with VLUs were randomized to either the intervention group (n = 22) or the control group (n = 27). Wound healing over 12 weeks. Intent-to-treat analysis showed a mean percentage wound area reduction at 12 weeks of 85.6% (SD, 28.6%) for the intervention group and 72.5% (SD, 77.8%) for the control group. There was a higher healing rate in the intervention group compared with patients who received SOC only at both week 4 (23% vs 11%) and week 12 (64% vs 59%). There were no adverse events related to the study therapy. Although the results were not significant, there was a trend toward faster healing in the intervention group. The results of this study indicate that collagen/oxidized regenerated cellulose/silver is a suitable and safe adjunctive intervention for use with SOC to manage VLUs.

Relationship between target organ damage and blood pressure, retinal vessel calibre, oxidative stress and polymorphisms in VAV-2 and VAV-3 genes in patients with hypertension: a case-control study protocol (LOD-Hipertension).

PubMed

Gomez-Marcos, Manuel A; Gonzalez-Sarmiento, Rogelio; Recio-Rodríguez, José I; Agudo-Conde, Cristina; Gamella-Pozuelo, Luis; Perretta-Tejedor, Nuria; Martínez-Salgado, Carlos; García-Ortiz, Luis

2014-04-03

Target organ damage (TOD) is associated with increased cardiovascular risk. The study objectives were to analyse the relationship of TOD to blood pressure, size of retinal arteries and veins, oxidative stress and different polymorphisms in the VAV-2 and VAV-3 genes in participants with hypertension. A case-control study to analyse the relationship between clinical, biochemical and genetic parameters and presence of cardiac, vascular and renal TOD in 486 patients with hypertension. Participants with TOD will be considered as cases, and those without TOD will be enrolled as controls. This will be a collaborative study conducted by the groups of Primary Care, Cardiovascular and Metabolic and Degenerative Diseases of the Instituto de Investigación Biomédica of Salamanca (IBSAL). Assessment of cardiac, renal and vascular TOD. Measurement of peripheral and central blood pressure, size of eye fundus arteries and veins, and oxidative stress, and polymorphisms in the VAV-2 and VAV-3 genes. The study will be conducted after approval is obtained from the Ethics Committee of Hospital Clínico Universitario of Salamanca. All study participants will sign an informed consent to agree to participate in the study, and another consent to agree on the genetic study, in compliance with the Declaration of Helsinki and the WHO standards for observational studies. The results of this study will allow for an understanding of the relationship of the different TODs with blood pressure, retinal artery and vein diameters, oxidative stress and polymorphisms in VAV-2 and VAV-3 genes. Clinical Trials. gov Identifier: NCT02022618.

Relationship between target organ damage and blood pressure, retinal vessel calibre, oxidative stress and polymorphisms in VAV-2 and VAV-3 genes in patients with hypertension: a case–control study protocol (LOD-Hipertensión)

PubMed Central

Gomez-Marcos, Manuel A; Gonzalez-Sarmiento, Rogelio; Recio-Rodríguez, José I; Agudo-Conde, Cristina; Gamella-Pozuelo, Luis; Perretta-Tejedor, Nuria; Martínez-Salgado, Carlos; García-Ortiz, Luis

2014-01-01

Introduction Target organ damage (TOD) is associated with increased cardiovascular risk. The study objectives were to analyse the relationship of TOD to blood pressure, size of retinal arteries and veins, oxidative stress and different polymorphisms in the VAV-2 and VAV-3 genes in participants with hypertension. Methods and analysis A case–control study to analyse the relationship between clinical, biochemical and genetic parameters and presence of cardiac, vascular and renal TOD in 486 patients with hypertension. Participants with TOD will be considered as cases, and those without TOD will be enrolled as controls. This will be a collaborative study conducted by the groups of Primary Care, Cardiovascular and Metabolic and Degenerative Diseases of the Instituto de Investigación Biomédica of Salamanca (IBSAL). Assessment of cardiac, renal and vascular TOD. Measurement of peripheral and central blood pressure, size of eye fundus arteries and veins, and oxidative stress, and polymorphisms in the VAV-2 and VAV-3 genes. Ethics and dissemination The study will be conducted after approval is obtained from the Ethics Committee of Hospital Clínico Universitario of Salamanca. All study participants will sign an informed consent to agree to participate in the study, and another consent to agree on the genetic study, in compliance with the Declaration of Helsinki and the WHO standards for observational studies. The results of this study will allow for an understanding of the relationship of the different TODs with blood pressure, retinal artery and vein diameters, oxidative stress and polymorphisms in VAV-2 and VAV-3 genes. Trial registration number Clinical Trials. gov Identifier: NCT02022618. PMID:24699462

40 CFR 52.2231 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Sulfur oxides and particulate matter. 52.2231 Section 52.2231 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.2231 Control strategy: Sulfur oxides and particulate matter. (a) Part D conditional approval. The...

40 CFR 52.1278 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Sulfur oxides and particulate matter. 52.1278 Section 52.1278 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...) Mississippi § 52.1278 Control strategy: Sulfur oxides and particulate matter. In a letter dated January 30...

40 CFR 52.2231 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Control strategy: Sulfur oxides and particulate matter. 52.2231 Section 52.2231 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.2231 Control strategy: Sulfur oxides and particulate matter. (a) Part D conditional approval. The...

40 CFR 52.2231 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Sulfur oxides and particulate matter. 52.2231 Section 52.2231 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.2231 Control strategy: Sulfur oxides and particulate matter. (a) Part D conditional approval. The...

40 CFR 52.1278 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Sulfur oxides and particulate matter. 52.1278 Section 52.1278 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...) Mississippi § 52.1278 Control strategy: Sulfur oxides and particulate matter. In a letter dated January 30...

40 CFR 52.2231 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 5 2013-07-01 2013-07-01 false Control strategy: Sulfur oxides and particulate matter. 52.2231 Section 52.2231 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.2231 Control strategy: Sulfur oxides and particulate matter. (a) Part D conditional approval. The...

40 CFR 52.1278 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Control strategy: Sulfur oxides and particulate matter. 52.1278 Section 52.1278 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...) Mississippi § 52.1278 Control strategy: Sulfur oxides and particulate matter. In a letter dated January 30...

40 CFR 52.2231 - Control strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 5 2014-07-01 2014-07-01 false Control strategy: Sulfur oxides and particulate matter. 52.2231 Section 52.2231 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.2231 Control strategy: Sulfur oxides and particulate matter. (a) Part D conditional approval. The...

Oxidative modification of lipoic acid by HNE in Alzheimer disease brain.

PubMed

Hardas, Sarita S; Sultana, Rukhsana; Clark, Amy M; Beckett, Tina L; Szweda, Luke I; Murphy, M Paul; Butterfield, D Allan

2013-01-01

Alzheimer disease (AD) is an age-related neurodegenerative disease characterized by the presence of three pathological hallmarks: synapse loss, extracellular senile plaques (SP) and intracellular neurofibrillary tangles (NFTs). The major component of SP is amyloid β-peptide (Aβ), which has been shown to induce oxidative stress. The AD brain shows increased levels of lipid peroxidation products, including 4-hydroxy-2-nonenal (HNE). HNE can react covalently with Cys, His, or Lys residues on proteins, altering structure and function of the latter. In the present study we measured the levels of the HNE-modified lipoic acid in brain of subjects with AD and age-matched controls. Lipoic acid is a key co-factor for a number of proteins including pyruvate dehydrogenase and α-ketoglutarate dehydrogenase, key complexes for cellular energetics. We observed a significant decrease in the levels of HNE-lipoic acid in the AD brain compared to that of age-matched controls. To investigate this phenomenon further, the levels and activity of lipoamide dehydrogenase (LADH) were measured in AD and control brains. Additionally, LADH activities were measured after in-vitro HNE-treatment to mice brains. Both LADH levels and activities were found to be significantly reduced in AD brain compared to age-matched control. HNE-treatment also reduced the LADH activity in mice brain. These data are consistent with a two-hit hypothesis of AD: oxidative stress leads to lipid peroxidation that, in turn, causes oxidative dysfunction of key energy-related complexes in mitochondria, triggering neurodegeneration. This study is consonant with the notion that lipoic acid supplementation could be a potential treatment for the observed loss of cellular energetics in AD and potentiate the antioxidant defense system to prevent or delay the oxidative stress in and progression of this devastating dementing disorder.

40 CFR 52.1475 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2012 CFR

2012-07-01

...: Sulfur oxides. 52.1475 Section 52.1475 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.1475 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of this... National Ambient Air Quality Standards for sulfur oxides in the Nevada Intrastate Region. (b) Article 8.1.3...

40 CFR 52.1475 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2013 CFR

2013-07-01

...: Sulfur oxides. 52.1475 Section 52.1475 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.1475 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of this... National Ambient Air Quality Standards for sulfur oxides in the Nevada Intrastate Region. (b) Article 8.1.3...

40 CFR 52.1475 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2011 CFR

2011-07-01

...: Sulfur oxides. 52.1475 Section 52.1475 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.1475 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of this... National Ambient Air Quality Standards for sulfur oxides in the Nevada Intrastate Region. (b) Article 8.1.3...

40 CFR 52.1475 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2014 CFR

2014-07-01

...: Sulfur oxides. 52.1475 Section 52.1475 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.1475 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of this... National Ambient Air Quality Standards for sulfur oxides in the Nevada Intrastate Region. (b) Article 8.1.3...

40 CFR 52.1475 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2010 CFR

2010-07-01

...: Sulfur oxides. 52.1475 Section 52.1475 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.1475 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of this... National Ambient Air Quality Standards for sulfur oxides in the Nevada Intrastate Region. (b) Article 8.1.3...

Redox proteomics analysis of HNE-modified proteins in Down syndrome brain: clues for understanding the development of Alzheimer disease.

PubMed

Di Domenico, Fabio; Pupo, Gilda; Tramutola, Antonella; Giorgi, Alessandra; Schininà, Maria Eugenia; Coccia, Raffaella; Head, Elizabeth; Butterfield, D Allan; Perluigi, Marzia

2014-06-01

Down syndrome (DS) is the most common genetic cause of intellectual disability, due to partial or complete triplication of chromosome 21. DS subjects are characterized by a number of abnormalities including premature aging and development of Alzheimer disease (AD) neuropathology after approximately 40 years of age. Several studies show that oxidative stress plays a crucial role in the development of neurodegeneration in the DS population. Increased lipid peroxidation is one of the main events causing redox imbalance within cells through the formation of toxic aldehydes that easily react with DNA, lipids, and proteins. In this study we used a redox proteomics approach to identify specific targets of 4-hydroxynonenal modifications in the frontal cortex from DS cases with and without AD pathology. We suggest that a group of identified proteins followed a specific pattern of oxidation in DS vs young controls, probably indicating characteristic features of the DS phenotype; a second group of identified proteins showed increased oxidation in DS/AD vs DS, thus possibly playing a role in the development of AD. The third group of comparison, DS/AD vs old controls, identified proteins that may be considered specific markers of AD pathology. All the identified proteins are involved in important biological functions including intracellular quality control systems, cytoskeleton network, energy metabolism, and antioxidant response. Our results demonstrate that oxidative damage is an early event in DS, as well as dysfunctions of protein-degradation systems and cellular protective pathways, suggesting that DS subjects are more vulnerable to oxidative damage accumulation that might contribute to AD development. Further, considering that the majority of proteins have been already demonstrated to be oxidized in AD brain, our results strongly support similarities with AD in DS. Copyright © 2014 Elsevier Inc. All rights reserved.

Lack of Effect of Sleep Apnea on Oxidative Stress in Obstructive Sleep Apnea Syndrome (OSAS) Patients

PubMed Central

Simiakakis, M.; Kapsimalis, F.; Chaligiannis, E.; Loukides, S.; Sitaras, N.; Alchanatis, M.

2012-01-01

Purpose The aim of this study was to evaluate markers of systemic oxidative stress and antioxidant capacity in subjects with and without OSAS in order to investigate the most important factors that determine the oxidant–antioxidant status. Methods A total of 66 subjects referred to our Sleep laboratory were examined by full polysomnography. Oxidative stress and antioxidant activity were assessed by measurement of the derivatives of reactive oxygen metabolites (d-ROMs) and the biological antioxidant capacity (BAP) in blood samples taken in the morning after the sleep study. Known risk factors for oxidative stress, such as age, sex, obesity, smoking, hypelipidemia, and hypertension, were investigated as possible confounding factors. Results 42 patients with OSAS (Apnea-Hypopnea index >15 events/hour) were compared with 24 controls (AHI<5). The levels of d-ROMS were significantly higher (p = 0.005) in the control group but the levels of antioxidant capacity were significantly lower (p = 0.004) in OSAS patients. The most important factors predicting the variance of oxidative stress were obesity, smoking habit, and sex. Parameters of sleep apnea severity were not associated with oxidative stress. Minimal oxygen desaturation and smoking habit were the most important predicting factors of BAP levels. Conclusion Obesity, smoking, and sex are the most important determinants of oxidative stress in OSAS subjects. Sleep apnea might enhance oxidative stress by the reduction of antioxidant capacity of blood due to nocturnal hypoxia. PMID:22761732

In-vitro assessment of oxidative stress generated by orthodontic archwires.

PubMed

Spalj, Stjepan; Mlacovic Zrinski, Magda; Tudor Spalj, Vedrana; Ivankovic Buljan, Zorana

2012-05-01

Several metals undergo redox cycling, producing free radicals and generating oxidative stress. The purpose of this study was to investigate in-vitro oxidative stress of orthodontic archwires made of various alloys. Mouse fibroblast cells L929 were exposed to 6 types of archwires, and the concentration of the oxidative stress marker 8-hydroxy-2'-deoxyguanosine in DNA was evaluated. Trypan blue dye was used in the determination of cell viability and numbers. Standard nickel-titanium archwires generated the highest oxidative stress, significantly higher than all other wires and the controls (P <0.05), and coated nickel-titanium, copper-nickel-titanium, and cobalt-chromium were lower than nickel-titanium (P <0.05), but higher than titanium-molybdenum and the negative and absolute controls (P <0.05). Titanium-molybdenum and stainless steel generated the lowest stress. Nickel-titanium induced the lowest viability, lower than the negative and absolute controls and all other wires (P <0.05) except titanium-molybdenum. Stainless steel showed the highest viability. Nickel-titanium produced the highest inhibition of cell growth, higher than all samples (P <0.05) except the positive control and cobalt-chromium. The lowest inhibition was observed in stainless steel and titanium-molybdenum, lower than nickel-titanium, cobalt-chromium, and the positive control (P <0.05). All orthodontic archwires generate oxidative stress in vitro. Stainless steel archwires have the highest and nickel-titanium the lowest biocompatibility. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

The controlled deposition of metal oxides onto carbon nanotubes by atomic layer deposition: examples and a case study on the application of V2O4 coated nanotubes in gas sensing.

PubMed

Willinger, Marc-Georg; Neri, Giovanni; Bonavita, Anna; Micali, Giuseppe; Rauwel, Erwan; Herntrich, Tobias; Pinna, Nicola

2009-05-21

A new atomic layer deposition (ALD) process was applied for the uniform coating of carbon nanotubes with a number of transition-metal oxide thin films (vanadium, titanium, and hafnium oxide). The presented approach is adapted from non-aqueous sol-gel chemistry and utilizes metal alkoxides and carboxylic acids as precursors. It allows the coating of the inner and outer surface of the tubes with a highly conformal film of controllable thickness and hence, the production of high surface area hybrid materials. The morphology and the chemical composition as well as the high purity of the films are evidenced through a combination of electron microscopic and electron-energy-loss spectrometric techniques. Furthermore, in order to highlight a possible application of the obtained hybrids, the electrical and sensing properties of resistive gas sensors based on hybrid vanadium oxide-coated carbon nanotubes (V2O4-CNTs) are reported and the effect of thermal treatment on the gas sensing properties is studied.

Oxidation mode of pyranose 2-oxidase is controlled by pH.

PubMed

Prongjit, Methinee; Sucharitakul, Jeerus; Palfey, Bruce A; Chaiyen, Pimchai

2013-02-26

Pyranose 2-oxidase (P2O) from Trametes multicolor is a flavoenzyme that catalyzes the oxidation of d-glucose and other aldopyranose sugars at the C2 position by using O₂ as an electron acceptor to form the corresponding 2-keto-sugars and H₂O₂. In this study, the effects of pH on the oxidative half-reaction of P2O were investigated using stopped-flow spectrophotometry. The results showed that flavin oxidation occurred via different pathways depending on the pH of the environment. At pH values lower than 8.0, reduced P2O reacts with O₂ to form a C4a-hydroperoxyflavin intermediate, leading to elimination of H₂O₂. At pH 8.0 and higher, the majority of the reduced P2O reacts with O₂ via a pathway that does not allow detection of the C4a-hydroperoxyflavin, and flavin oxidation occurs with decreased rate constants upon the rise in pH. The switching between the two modes of P2O oxidation is controlled by protonation of a group which has a pK(a) of 7.6 ± 0.1. Oxidation reactions of reduced P2O under rapid pH change as performed by stopped-flow mixing were different from the same reactions performed with enzyme pre-equilibrated at the same specified pH values, implying that the protonation of the group which controls the mode of flavin oxidation cannot be rapidly equilibrated with outside solvent. Using a double-mixing stopped-flow experiment, a rate constant for proton dissociation from the reaction site was determined to be 21.0 ± 0.4 s⁻¹.

Research: Treatment A randomized crossover study to assess the effect of an oat-rich diet on glycaemic control, plasma lipids and postprandial glycaemia, inflammation and oxidative stress in Type 2 diabetes

PubMed Central

McGeoch, S C; Johnstone, A M; Lobley, G E; Adamson, J; Hickson, K; Holtrop, G; Fyfe, C; Clark, L F; Pearson, D W M; Abraham, P; Megson, I L; MacRury, S M

2013-01-01

Aims In the UK, lifestyle intervention is first-line management in Type 2 diabetes. It is unclear what type of diet is most efficacious for improving glycaemic control. This study investigated the effects of an oat-enriched diet on glycaemic control, postprandial glycaemia, inflammation and oxidative stress compared with standard dietary advice. Methods In a randomized crossover design, 27 volunteers with Type 2 diabetes, managed on diet and lifestyle only, were observed for two consecutive 8-week periods following either the oat-enriched diet or re-enforced standard dietary advice. Volunteers attended at baseline (habitual intake) and 8 and 16 weeks. Measurements included basic clinical measurements and fasted and postprandial (3-h) glucose and insulin in response to a healthy test meal. Markers of inflammation and oxidative stress, including high-sensitivity C-reactive protein, interleukin 6, interleukin 18, tumour necrosis factor-alpha, adiponectin, thiobarbituric acid reactive substances, oxygen radical antioxidant capacity, oxidized LDL and urinary isoprostanes, were also measured at fasting and in the postprandial period. Results There were no diet-related effects on glycaemic control or glycaemic or insulinaemic responses to the test meal. Total cholesterol (5.1 ± 1.0 vs. 4.9 ± 0.8 mmol/l, P = 0.019) concentrations declined following the oat-enriched diet compared with standard dietary advice. There was a postprandial decline in adiponectin concentration (P = 0.009), but no effect of dietary intervention. None of the measures of oxidative stress or inflammation were altered by the oat-enriched diet compared with standard dietary advice. Conclusion The oat-enriched diet had a modest impact on lipid lowering, but did not impact on oxidative stress or inflammation in these volunteers with Type 2 diabetes. PMID:23668675

40 CFR 52.57 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control strategy: Sulfur oxides. 52.57... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.57 Control strategy: Sulfur oxides... for attainment and maintenance of the national standards for sulfur oxides in the vicinity of the...

40 CFR 52.57 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control strategy: Sulfur oxides. 52.57... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.57 Control strategy: Sulfur oxides... for attainment and maintenance of the national standards for sulfur oxides in the vicinity of the...

40 CFR 52.57 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Control strategy: Sulfur oxides. 52.57... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.57 Control strategy: Sulfur oxides... for attainment and maintenance of the national standards for sulfur oxides in the vicinity of the...

40 CFR 52.57 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control strategy: Sulfur oxides. 52.57... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.57 Control strategy: Sulfur oxides... for attainment and maintenance of the national standards for sulfur oxides in the vicinity of the...

40 CFR 52.57 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Sulfur oxides. 52.57... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.57 Control strategy: Sulfur oxides... for attainment and maintenance of the national standards for sulfur oxides in the vicinity of the...

Flavonoid-rich apples and nitrate-rich spinach augment nitric oxide status and improve endothelial function in healthy men and women: a randomized controlled trial.

PubMed

Bondonno, Catherine P; Yang, Xingbin; Croft, Kevin D; Considine, Michael J; Ward, Natalie C; Rich, Lisa; Puddey, Ian B; Swinny, Ewald; Mubarak, Aidilla; Hodgson, Jonathan M

2012-01-01

Flavonoids and nitrates in fruits and vegetables may protect against cardiovascular disease. Dietary flavonoids and nitrates can augment nitric oxide status via distinct pathways, which may improve endothelial function and lower blood pressure. Recent studies suggest that the combination of flavonoids and nitrates can enhance nitric oxide production in the stomach. Their combined effect in the circulation is unclear. Here, our objective was to investigate the independent and additive effects of flavonoid-rich apples and nitrate-rich spinach on nitric oxide status, endothelial function, and blood pressure. A randomized, controlled, crossover trial with healthy men and women (n=30) was conducted. The acute effects of four energy-matched treatments (control, apple, spinach, and apple+spinach), administered in random order, were compared. Measurements included plasma nitric oxide status, assessed by measuring S-nitrosothiols+other nitrosylated species (RXNO) and nitrite, blood pressure, and endothelial function, measured as flow-mediated dilatation of the brachial artery. Results are means and 95% CI. Relative to control, all treatments resulted in higher RXNO (control, 33 nmol/L, 26, 42; apple, 51 nmol/L, 40, 65; spinach, 86 nmol/L, 68, 110; apple+spinach, 69 nmol/L, 54, 88; P<0.01) and higher nitrite (control, 35 nmol/L, 27, 46; apple, 69 nmol/L, 53, 90; spinach, 99 nmol/L, 76, 129; apple+spinach, 80 nmol/L, 61, 104; P<0.01). Compared to control, all treatments resulted in higher flow-mediated dilatation (P<0.05) and lower pulse pressure (P<0.05), and apple and spinach resulted in lower systolic blood pressure (P<0.05). No significant effect was observed on diastolic blood pressure. The combination of apple and spinach did not result in additive effects on nitric oxide status, endothelial function, or blood pressure. In conclusion, flavonoid-rich apples and nitrate-rich spinach can independently augment nitric oxide status, enhance endothelial function, and lower blood pressure acutely, outcomes that may benefit cardiovascular health. Copyright © 2011 Elsevier Inc. All rights reserved.

Study on a discrete-time dynamic control model to enhance nitrogen removal with fluctuation of influent in oxidation ditches.

PubMed

Liu, Yanchen; Shi, Hanchang; Shi, Huiming; Wang, Zhiqiang

2010-10-01

The aim of study was proposed a new control model feasible on-line implemented by Programmable Logic Controller (PLC) to enhance nitrogen removal against the fluctuation of influent in Carrousel oxidation ditch. The discrete-time control model was established by confirmation model of operational conditions based on a expert access, which was obtained by a simulation using Activated Sludge Model 2-D (ASM2-D) and Computation Fluid Dynamics (CFD), and discrete-time control model to switch between different operational stages. A full-scale example is provided to demonstrate the feasibility of the proposed operation and the procedure of the control design. The effluent quality was substantially improved, to the extent that it met the new wastewater discharge standards of NH(3)-N<5mg/L and TN<15 mg/L enacted in China throughout a one-day period with fluctuation of influent. Copyright © 2010 Elsevier Ltd. All rights reserved.

The oxidation mode of pyranose 2-oxidase is controlled by pH

PubMed Central

Prongjit, Methinee; Sucharitakul, Jeerus; Palfey, Bruce A.; Chaiyen, Pimchai

2013-01-01

Pyranose 2-oxidase (P2O) from Trametes multicolor is a flavoenzyme that catalyzes the oxidation of D-glucose and other aldopyranose sugars at the C2 position by using O2 as an electron acceptor to form the corresponding 2-keto-sugars and H2O2. In this study, the effects of pH on the oxidative half-reaction of P2O were investigated using stopped-flow spectrophotometry. The results showed that flavin oxidation occurred via different pathways depending on the pH of the environment. At pH values lower than 8.0, reduced P2O reacts with O2 to form a C4a-hydroperoxy-flavin intermediate, leading to elimination of H2O2. At pH 8.0 and higher, the majority of the reduced P2O reacts with O2 via a pathway which does not allow detection of the C4a-hydroperoxy-flavin, and flavin oxidation occurs with decreased rate constants upon the rise in pH. The switching between the two modes of P2O oxidation is controlled by protonation of a group which has a pKa of 7.6 ± 0.1. Oxidation reactions of reduced P2O under rapid pH change as performed by stopped-flow mixing were different from the same reactions performed with enzyme pre-equilibrated at the same specified pH values, implying that the protonation of the group which controls the mode of flavin oxidation cannot be rapidly equilibrated with outside solvent. Using a double-mixing stopped-flow experiment, a rate constant for proton dissociation from the reaction site was determined to be 21.0 ± 0.4 s-1. PMID:23356577

Aerosol composition, oxidative properties, and sources in Beijing: results from the 2014 Asia-Pacific Economic Cooperation Summit study

NASA Astrophysics Data System (ADS)

Xu, W. Q.; Sun, Y. L.; Chen, C.; Du, W.; Han, T. T.; Wang, Q. Q.; Fu, P. Q.; Wang, Z. F.; Zhao, X. J.; Zhou, L. B.; Ji, D. S.; Wang, P. C.; Worsnop, D. R.

2015-08-01

The mitigation of air pollution in megacities remains a great challenge because of the complex sources and formation mechanisms of aerosol particles. The 2014 Asia- Pacific Economic Cooperation (APEC) summit in Beijing serves as a unique experiment to study the impacts of emission controls on aerosol composition, size distributions, and oxidative properties. Herein, a high-resolution time-of-flight aerosol mass spectrometer was deployed in urban Beijing for real-time measurements of size-resolved non-refractory submicron aerosol (NR-PM1) species from 14 October to 12 November 2014, along with a range of collocated measurements. The average (±σ) PM1 was 41.6 (±38.9) μg m-3 during APEC, which was decreased by 53 % compared with that before APEC. The aerosol composition showed substantial changes owing to emission controls during APEC. Secondary inorganic aerosols (SIA = sulfate + nitrate + ammonium) showed significant reductions of 62-69 %, whereas organics presented much smaller decreases (35 %). The results from the positive matrix factorization of organic aerosols (OA) indicated that highly oxidized secondary OA (SOA) showed decreases similar to those of SIA during APEC. However, primary OA (POA) from cooking, traffic, and biomass burning sources were comparable to those before APEC, indicating the presence of strong local source emissions. The oxidation properties showed corresponding changes in response to OA composition. The average oxygen-to-carbon level during APEC was 0.36 (±0.10), which is lower than the 0.43 (±0.13) measured before APEC, demonstrating a decrease in the OA oxidation degree. The changes in size distributions of primary and secondary species varied during APEC. SIA and SOA showed significant reductions in large accumulation modes with peak diameters shifting from ~ 650 to 400 nm during APEC, whereas those of POA remained relatively unchanged. The changes in aerosol composition, size distributions, and oxidation degrees during the aging processes were further illustrated in a case study of a severe haze episode. Our results elucidated a complex response of aerosol chemistry to emission controls, which has significant implications that emission controls over regional scales can substantially reduce secondary particulates. However, stricter emission controls for local source emissions are needed for further mitigating air pollution in the megacity of Beijing.

Aerosol composition, oxidation properties, and sources in Beijing: results from the 2014 Asia-Pacific Economic Cooperation summit study

NASA Astrophysics Data System (ADS)

Xu, W. Q.; Sun, Y. L.; Chen, C.; Du, W.; Han, T. T.; Wang, Q. Q.; Fu, P. Q.; Wang, Z. F.; Zhao, X. J.; Zhou, L. B.; Ji, D. S.; Wang, P. C.; Worsnop, D. R.

2015-12-01

The mitigation of air pollution in megacities remains a great challenge because of the complex sources and formation mechanisms of aerosol particles. The 2014 Asia-Pacific Economic Cooperation (APEC) summit in Beijing serves as a unique experiment to study the impacts of emission controls on aerosol composition, size distributions, and oxidation properties. Herein, a high-resolution time-of-flight aerosol mass spectrometer was deployed in urban Beijing for real-time measurements of size-resolved non-refractory submicron aerosol (NR-PM1) species from 14 October to 12 November 2014, along with a range of collocated measurements. The average (±σ) PM1 was 41.6 (±38.9) μg m-3 during APEC, which was decreased by 53 % compared with that before APEC. The aerosol composition showed substantial changes owing to emission controls during APEC. Secondary inorganic aerosol (SIA: sulfate + nitrate + ammonium) showed significant reductions of 62-69 %, whereas organics presented much smaller decreases (35 %). The results from the positive matrix factorization of organic aerosol (OA) indicated that highly oxidized secondary organic aerosol (SOA) showed decreases similar to those of SIA during APEC. However, primary organic aerosol (POA) from cooking, traffic, and biomass-burning sources were comparable to those before APEC, indicating the presence of strong local source emissions. The oxidation properties showed corresponding changes in response to OA composition. The average oxygen-to-carbon level during APEC was 0.36 (±0.10), which is lower than the 0.43 (±0.13) measured before APEC, demonstrating a decrease in the OA oxidation degree. The changes in size distributions of primary and secondary species varied during APEC. SIA and SOA showed significant reductions in large accumulation modes with peak diameters shifting from ~ 650 to 400 nm during APEC, whereas those of POA remained relatively unchanged. The changes in aerosol composition, size distributions, and oxidation degrees during the aging processes were further illustrated in a case study of a severe haze episode. Our results elucidated a complex response of aerosol chemistry to emission controls, which has significant implications that emission controls over regional scales can substantially reduce secondary particulates. However, stricter emission controls for local source emissions are needed for further mitigating air pollution in the megacity of Beijing.

Comparative effects of red and white grapes on oxidative markers and lipidemic parameters in adult hypercholesterolemic humans.

PubMed

Rahbar, Ali Reza; Mahmoudabadi, Mohammad Mehdi Shakouri; Islam, Md Shahidul

2015-06-01

The present study compared the effects of consuming red versus white whole grapes on oxidative and lipidemic indices in people with hypercholesterolemia. Sixty nine patients were randomized into three groups. The two treatment groups consumed 500 g of either Condori red grapes or Shahroodi white grapes daily for 8 weeks, and the third group served as a control. Plasma glucose, triacylglycerol (TG), cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), thiobarbituric acid reactive substances (TBARS) and total antioxidant capacity (TAC) were determined by colorimetric methods at baseline and at the end of the study. In addition, the polyphenol and fiber content of the two grape varieties was measured. TBARS was reduced in both study groups compared to the control group, and the reduction was greater in the group that consumed red grapes compared to the white grapes. TAC was increased significantly in both red and white grape consuming groups compared to the control group. Total cholesterol and LDL-C were decreased in the red grape group compared to the control group. No significant changes in fasting blood glucose, TG or HDL-C were observed among the groups. The results of this study suggest that consumption of the whole fruit of red grapes has more potent anti-oxidative and hypolipidemic effects compared to the white grapes in hyperlipidemic adult humans. Hence, the whole fruit of red grapes may be an excellent fruit choice not only to prevent oxidative stress related metabolic disorders but also cholesterol related cardiovascular diseases, particularly in hyperlipidemic adult humans.

Protective effects of Spirulina maxima on hyperlipidemia and oxidative-stress induced by lead acetate in the liver and kidney

PubMed Central

2010-01-01

Background Oxidative damage has been proposed as a possible mechanism involved in lead toxicity, specially affecting the liver and kidney. Previous studies have shown the antioxidant effect of Spirulina maxima in several experimental models of oxidative stress. The current study was carried out to evaluate the antioxidant activity of Spirulina maxima against lead acetate-induced hyperlipidemia and oxidative damage in the liver and kidney of male rats. Control animals were fed on a standard diet and did not receive lead acetate (Control group). Experimental animals were fed on a standard laboratory diet with or without Spirulina maxima 5% in the standard laboratory diet and treated with three doses of lead acetate (25 mg each/weekly, intraperitoneal injection) (lead acetate with Spirulina, and lead acetate without Spirulina groups). Results The results showed that Spirulina maxima prevented the lead acetate-induced significant changes on plasma and liver lipid levels and on the antioxidant status of the liver and kidney. On the other hand, Spirulina maxima succeeded to improve the biochemical parameters of the liver and kidney towards the normal values of the Control group. Conclusions It was concluded that Spirulina maxima has protective effects on lead acetate-induced damage, and that the effects are associated with the antioxidant effect of Spirulina. PMID:20353607

Protective effects of Spirulina maxima on hyperlipidemia and oxidative-stress induced by lead acetate in the liver and kidney.

PubMed

Ponce-Canchihuamán, Johny C; Pérez-Méndez, Oscar; Hernández-Muñoz, Rolando; Torres-Durán, Patricia V; Juárez-Oropeza, Marco A

2010-03-31

Oxidative damage has been proposed as a possible mechanism involved in lead toxicity, specially affecting the liver and kidney. Previous studies have shown the antioxidant effect of Spirulina maxima in several experimental models of oxidative stress. The current study was carried out to evaluate the antioxidant activity of Spirulina maxima against lead acetate-induced hyperlipidemia and oxidative damage in the liver and kidney of male rats. Control animals were fed on a standard diet and did not receive lead acetate (Control group). Experimental animals were fed on a standard laboratory diet with or without Spirulina maxima 5% in the standard laboratory diet and treated with three doses of lead acetate (25 mg each/weekly, intraperitoneal injection) (lead acetate with Spirulina, and lead acetate without Spirulina groups). The results showed that Spirulina maxima prevented the lead acetate-induced significant changes on plasma and liver lipid levels and on the antioxidant status of the liver and kidney. On the other hand, Spirulina maxima succeeded to improve the biochemical parameters of the liver and kidney towards the normal values of the Control group. It was concluded that Spirulina maxima has protective effects on lead acetate-induced damage, and that the effects are associated with the antioxidant effect of Spirulina.

Effect of montelukast monotherapy on oxidative stress parameters and DNA damage in children with asthma.

PubMed

Dilek, Fatih; Ozkaya, Emin; Kocyigit, Abdurrahim; Yazici, Mebrure; Kesgin, Siddika; Gedik, Ahmet Hakan; Cakir, Erkan

2015-01-01

There is ample knowledge reported in the literature about the role of oxidative stress in asthma pathogenesis. It is also known that the interaction of reactive oxygen species with DNA may result in DNA strand breaks. The aim of this study was to investigate if montelukast monotherapy affects oxidative stress and DNA damage parameters in a population of pediatric asthma patients. Group I consisted of 31 newly diagnosed asthmatic patients not taking any medication, and group II consisted of 32 patients who had been treated with montelukast for at least 6 months. Forty healthy control subjects were also enrolled in the study. Plasma total oxidant status (TOS) and total antioxidant status (TAS) were measured to assess oxidative stress. DNA damage was assessed by means of alkaline comet assay. The patients in both group I and group II had statistically significant higher plasma TOS (13.1 ± 4 and 11.1 ± 4.1 μmol H2O2 equivalent/liter, respectively) and low TAS levels (1.4 ± 0.5 and 1.5 ± 0.5 mmol Trolox equivalent/liter, respectively) compared with the control group (TOS: 6.3 ± 3.5 μmol H2O2 equivalent/liter and TAS: 2.7 ± 0.6 mmol Trolox equivalent/liter; p < 0.05). DNA damage was 18.2 ± 1.0 arbitrary units (a.u.) in group I, 16.7 ± 8.2 a.u. in group II and 13.7 ± 3.4 a.u. in the control group. There were statistically significant differences only between group I and the control group (p < 0.05). According to the findings, montelukast therapy makes only minimal but not statistically significant improvement in all TOS, TAS and DNA damage parameters. © 2015 S. Karger AG, Basel.

Oxidative stress in recurrent pregnancy loss women.

PubMed

Baban, Rayah S

2010-07-01

To investigate biochemical changes in lipid peroxidation, nitric oxide, and vitamin E in recurrent pregnancy loss women, and compare these with healthy pregnant, and non-pregnant women. A case control study was conducted from September 2008 to December 2009 at Al-Khadimiya Teaching Hospital, Baghdad, Iraq. Ninety-six subjects were included in the study, 32 were patients with recurrent pregnancy loss (RPL), and 32 pregnant women in their third trimester, and another 32 non-pregnant women were used as controls. Blood samples were collected from each patient at the time of pregnancy loss. Serum from patients and controls was then used to estimate malondialdehyde (MDA), nitric oxide (NO), and vitamin E levels. There was a significant elevation in patient serum MDA compared with third trimester pregnant women (p=0.002) and non-pregnant women (p=0.0001). Both serum vitamin E and NO levels in RPL patients also showed a highly significant decrease compared with third trimester pregnant, and non-pregnant women. A highly significant difference was found in the MDA/vitamin E ratio between RPL and control groups, while no significance was found between RPL and control groups' NO/vitamin E ratio. The decrease in NO production and vitamin E is a result of RPL and not a causative factor, as the RPL was without pathological cause, medication, or fibroid presence, and no significant difference was found between the NO/vitamin E ratio in RPL and controls group.

Controlling Oxygen Mobility in Ruddlesden–Popper Oxides

PubMed Central

Lee, Dongkyu; Lee, Ho Nyung

2017-01-01

Discovering new energy materials is a key step toward satisfying the needs for next-generation energy conversion and storage devices. Among the various types of oxides, Ruddlesden–Popper (RP) oxides (A2BO4) are promising candidates for electrochemical energy devices, such as solid oxide fuel cells, owing to their attractive physicochemical properties, including the anisotropic nature of oxygen migration and controllable stoichiometry from oxygen excess to oxygen deficiency. Thus, understanding and controlling the kinetics of oxygen transport are essential for designing optimized materials to use in electrochemical energy devices. In this review, we first discuss the basic mechanisms of oxygen migration in RP oxides depending on oxygen nonstoichiometry. We then focus on the effect of changes in the defect concentration, crystallographic orientation, and strain on the oxygen migration in RP oxides. We also briefly review their thermal and chemical stability. Finally, we conclude with a perspective on potential research directions for future investigation to facilitate controlling oxygen ion migration in RP oxides. PMID:28772732

Oxidation of elemental mercury vapor over gamma-Al2O3 supported CuCl2 catalyst for mercury emissions control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Zhouyang; Liu, Xin; Lee, Joo-Youp

2015-09-01

In our previous studies, CuCl2 demonstrated excellent Hg(0) oxidation capability and holds potential for Hg(0) oxidation in coal-fired power plants. In this study, the properties and performances of CuCl2 supported onto gamma-Al2O3 with high surface area were investigated. From various characterization techniques using XPS, XAFS, XRD, TPR, SEM and TGA, the existence of multiple copper species was identified. At low CuCl2 loadings, CuCl2 forms copper aluminate species with gamma-Al2O3 and is inactive for Hg(0) oxidation. At high loadings, amorphous CuCl2 forms onto the gamma-Al2O3 surface, working as a redox catalyst for Hg(0) oxidation by consuming Cl to be converted intomore » CuCl and then being regenerated back into CuCl2 in the presence of O-2 and HCl gases. The 10%(wt) CuCl2/gamma-Al2O3 catalyst showed excellent Hg(0) oxidation performance and SO2 resistance at 140 degrees C under simulated flue gas conditions containing 6%(v) O-2 and 10 ppmv HCl. The oxidized Hg(0) in the form of HgCl2 has a high solubility in water and can be easily captured by other air pollution control systems such as wet scrubbers in coal-fired power plants. The CuCl2/gamma-Al2O3 catalyst can be used as a low temperature Hg(0) oxidation catalyst. (C) 2015 Elsevier B.V. All rights reserved.« less

Cryptosporidium-contaminated water disinfection by a novel Fenton process.

PubMed

Matavos-Aramyan, Sina; Moussavi, Mohsen; Matavos-Aramyan, Hedieh; Roozkhosh, Sara

2017-05-01

Three novel modified advanced oxidation process systems including ascorbic acid-, pro-oxidants- and ascorbic acid-pro-oxidants-modified Fenton system were utilized to study the disinfection efficiency on Cryptosporidium-contaminated drinking water samples. Different concentrations of divalent and trivalent iron ions, hydrogen peroxide, ascorbic acid and pro-oxidants at different exposure times were investigated. These novel systems were also compared to the classic Fenton system and to the control system which comprised of only hydrogen peroxide. The complete in vitro mechanism of the mentioned modified Fenton systems are also provided. The results pointed out that by considering the optimal parameter limitations, the ascorbic acid-modified Fenton system decreased the Cryptosporidium oocytes viability to 3.91%, while the pro-oxidant-modified and ascorbic acid-pro-oxidant-modified Fenton system achieved an oocytes viability equal to 1.66% and 0%, respectively. The efficiency of the classic Fenton at optimal condition was observed to be 20.12% of oocytes viability. The control system achieved 86.14% of oocytes viability. The optimum values of the operational parameters during this study are found to be 80mgL -1 for the divalent iron, 30mgL -1 for ascorbic acid, 30mmol for hydrogen peroxide, 25mgL -1 for pro-oxidants and an exposure time equal to 5min. The ascorbic acid-pro-oxidants-modified Fenton system achieved a promising complete water disinfection (0% viability) at the optimal conditions, leaving this method a feasible process for water disinfection or decontamination, even at industrial scales. Copyright © 2017 Elsevier Inc. All rights reserved.

BCL-2 inhibition targets oxidative phosphorylation and selectively eradicates quiescent human leukemia stem cells

PubMed Central

Lagadinou, Eleni D.; Sach, Alexander; Callahan, Kevin; Rossi, Randall M.; Neering, Sarah J.; Minhajuddin, Mohammad; Ashton, John M.; Pei, Shanshan; Grose, Valerie; O’Dwyer, Kristen M.; Liesveld, Jane L.; Brookes, Paul S.; Becker, Michael W.; Jordan, Craig T.

2013-01-01

Summary Most forms of chemotherapy employ mechanisms involving induction of oxidative stress, a strategy that can be effective due to the elevated oxidative state commonly observed in cancer cells. However, recent studies have shown that relative redox levels in primary tumors can be heterogeneous, suggesting that regimens dependent on differential oxidative state may not be uniformly effective. To investigate this issue in hematological malignancies, we evaluated mechanisms controlling oxidative state in primary specimens derived from acute myelogenous leukemia (AML) patients. Our studies demonstrate three striking findings. First, the majority of functionally-defined leukemia stem cells (LSCs) are characterized by relatively low levels of reactive oxygen species (termed “ROS-low”). Second, ROS-low LSCs aberrantly over-express BCL-2. Third, BCL-2 inhibition reduced oxidative phosphorylation and selectively eradicated quiescent LSCs. Based on these findings, we propose a model wherein the unique physiology of ROS-low LSCs provides an opportunity for selective targeting via disruption of BCL-2-dependent oxidative phosphorylation. PMID:23333149

Sarcoptic mange in dogs: Its effect on liver, oxidative stress, trace minerals and vitamins.

PubMed

Beigh, S A; Soodan, J S; Bhat, A M

2016-08-30

The present study was aimed to determine the effect on liver, associated oxidative stress, trace element and vitamin alteration in dogs with sarcoptic mange. A total of 24 dogs with clinically established diagnosis of sarcoptic mange, divided into two groups, severely infested group (n=9) and mild/moderately infested group (n=15), according to the extent of skin lesions caused by sarcoptic mange and 6 dogs as control group were included in the present study. In comparison to healthy control hemoglobin, PCV, and TEC were significantly (P<0.05) decreased in dogs with sarcoptic mange however, significant increase in TLC along with neutrophilia and lymphopenia was observed only in severely infested dogs. The albumin, glucose and cholesterol were significantly (P<0.05) decreased and globulin, ALT, AST and bilirubin were significantly (P<0.05) increased in severely infested dogs when compared to other two groups. Malondialdehyde (MDA) levels were significantly (P<0.01) higher in dogs with sarcoptic mange, with levels highest in severely infested groups. Activity of superoxide dismutase (SOD) (P<0.05) and catalase were significantly (P<0.01) lower in sarcoptic infested dogs when compared with the healthy control group. Zinc and copper levels in dogs with sarcoptic mange were significantly (P<0.05) lower when compared with healthy control group with the levels lowest in severely infested group. Vitamin A and vitamin C levels were significantly (P<0.05) lower in sarcoptic infested dogs when compared to healthy control. From the present study, it was concluded that sarcoptic mange in dogs affects the liver and the infestation is associated with oxidant/anti-oxidant imbalance, significant alteration in trace elements and vitamins. Copyright © 2016 Elsevier B.V. All rights reserved.

40 CFR Appendix B to Part 76 - Procedures and Methods for Estimating Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers

Code of Federal Regulations, 2010 CFR

2010-07-01

... Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers B Appendix B to Part 76 Protection of... of Nitrogen Oxides Controls Applied to Group 1, Boilers 1. Purpose and Applicability This technical...; and which is comparable to the costs of nitrogen oxides controls set pursuant to subsection (b)(1) (of...

40 CFR Appendix B to Part 76 - Procedures and Methods for Estimating Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers

Code of Federal Regulations, 2012 CFR

2012-07-01

... Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers B Appendix B to Part 76 Protection of... of Nitrogen Oxides Controls Applied to Group 1, Boilers 1. Purpose and Applicability This technical...; and which is comparable to the costs of nitrogen oxides controls set pursuant to subsection (b)(1) (of...

40 CFR Appendix B to Part 76 - Procedures and Methods for Estimating Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers

Code of Federal Regulations, 2013 CFR

2013-07-01

... Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers B Appendix B to Part 76 Protection of... of Nitrogen Oxides Controls Applied to Group 1, Boilers 1. Purpose and Applicability This technical...; and which is comparable to the costs of nitrogen oxides controls set pursuant to subsection (b)(1) (of...

40 CFR Appendix B to Part 76 - Procedures and Methods for Estimating Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers

Code of Federal Regulations, 2011 CFR

2011-07-01

... Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers B Appendix B to Part 76 Protection of... of Nitrogen Oxides Controls Applied to Group 1, Boilers 1. Purpose and Applicability This technical...; and which is comparable to the costs of nitrogen oxides controls set pursuant to subsection (b)(1) (of...

40 CFR Appendix B to Part 76 - Procedures and Methods for Estimating Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers

Code of Federal Regulations, 2014 CFR

2014-07-01

... Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers B Appendix B to Part 76 Protection of... of Nitrogen Oxides Controls Applied to Group 1, Boilers 1. Purpose and Applicability This technical...; and which is comparable to the costs of nitrogen oxides controls set pursuant to subsection (b)(1) (of...

Antiparasite treatments reduce humoral immunity and impact oxidative status in raptor nestlings

PubMed Central

Hanssen, Sveinn Are; Bustnes, Jan Ove; Schnug, Lisbeth; Bourgeon, Sophie; Johnsen, Trond Vidar; Ballesteros, Manuel; Sonne, Christian; Herzke, Dorte; Eulaers, Igor; Jaspers, Veerle L B; Covaci, Adrian; Eens, Marcel; Halley, Duncan J; Moum, Truls; Ims, Rolf Anker; Erikstad, Kjell Einar

2013-01-01

Parasites are natural stressors that may have multiple negative effects on their host as they usurp energy and nutrients and may lead to costly immune responses that may cause oxidative stress. At early stages, animals may be more sensitive to infectious organisms because of their rapid growth and partly immature immune system. The objective of this study was to explore effects of parasites by treating chicks of two raptor species (northern goshawk Accipiter gentilis and white-tailed sea eagle Haliaeetus albicilla) against both endoparasites (internal parasites) and ectoparasites (external parasites). Nests were either treated against ectoparasites by spraying with pyrethrin or left unsprayed as control nests. Within each nest, chicks were randomly orally treated with either an antihelminthic medication (fenbendazole) or sterile water as control treatment. We investigated treatment effects on plasma (1) total antioxidant capacity TAC (an index of nonenzymatic circulating antioxidant defenses), (2) total oxidant status TOS (a measure of plasmatic oxidants), and (3) immunoglobulin levels (a measure of humoral immune function). Treatment against ectoparasites led to a reduction in circulating immunoglobulin plasma levels in male chicks. TOS was higher when not receiving any parasite reduction treatment and when receiving both endo- and ectoparasitic reduction treatment compared with receiving only one treatment. TAC was higher in all treatment groups, when compared to controls. Despite the relatively low sample size, this experimental study suggests complex but similar relationships between treatment groups and oxidative status and immunoglobulin levels in two raptor species. PMID:24455145

Integrated Science Assessment (ISA) for Sulfur Oxides – Health Criteria (Final)

EPA Science Inventory

The SOx ISA reviews information on atmospheric science, exposure, dosimetry, mode of action, and health effects related to sulfur oxides and sulfur dioxide (SO2), including evidence from controlled human exposure, epidemiologic, and toxicological studies.

Exposure control practices for administering nitrous oxide: A survey of dentists, dental hygienists, and dental assistants.

PubMed

Boiano, James M; Steege, Andrea L; Sweeney, Marie H

2017-06-01

Engineering, administrative, and work practice controls have been recommended for many years to minimize exposure to nitrous oxide during dental procedures. To better understand the extent to which these exposure controls are used, the NIOSH Health and Safety Practices Survey of Healthcare Workers was conducted among members of professional practice organizations representing dentists, dental hygienists and dental assistants. The anonymous, modular, web-based survey was completed by 284 dental professionals in private practice who administered nitrous oxide to adult and/or pediatric patients in the seven days prior to the survey. Use of primary engineering controls (i.e., nasal scavenging mask and/or local exhaust ventilation (LEV) near the patient's mouth) was nearly universal, reported by 93% and 96% of respondents who administered to adult (A) and pediatric (P) patients, respectively. However, adherence to other recommended precautionary practices were lacking to varying degrees, and were essentially no different among those administering nitrous oxide to adult or pediatric patients. Examples of work practices which increase exposure risk, expressed as percent of respondents, included: not checking nitrous oxide equipment for leaks (41% A; 48% P); starting nitrous oxide gas flow before delivery mask or airway mask was applied to patient (13% A; 12% P); and not turning off nitrous oxide gas flow before turning off oxygen flow to the patient (8% A; 7% P). Absence of standard procedures to minimize worker exposure to nitrous oxide (13% of all respondents) and not being trained on safe handling and administration of nitrous oxide (3%) were examples of breaches of administrative controls which may also increase exposure risk. Successful management of nitrous oxide emissions should include properly fitted nasal scavenging masks, supplemental LEV (when nitrous oxide levels cannot be adequately controlled using nasal masks alone), adequate general ventilation, regular inspection of nitrous oxide delivery and scavenging equipment for leaks, availability of standard procedures to minimize exposure, periodic training, ambient air and exposure monitoring, and medical surveillance.

Controls on nitrous oxide production and consumption in reservoirs of the Ohio River Basin

EPA Science Inventory

Aquatic ecosystems are a globally significant source of nitrous oxide (N2O), a potent greenhouse gas, but estimates are largely based on studies conducted in streams and rivers with relatively less known about N2O dynamics in lakes and reservoirs. Due to long water residence tim...

Nitrous Oxide Production in an Eastern Corn Belt Soil: Sources and Redox Range

USDA-ARS?s Scientific Manuscript database

Nitrous oxide (N2O) derived from soils is a main contributor to the greenhouse gas effect and a precursor to ozone-depleting substrates; however, the source processes and interacting controls are not well established. This study was conducted to estimate magnitude and source (nitrification vs. denit...

Oxidative Stress Correlates with Headache Symptoms in Fibromyalgia: Coenzyme Q10 Effect on Clinical Improvement

PubMed Central

Cordero, Mario D.; Cano-García, Francisco Javier; Alcocer-Gómez, Elísabet; De Miguel, Manuel; Sánchez-Alcázar, José Antonio

2012-01-01

Background Fibromyalgia (FM) is a chronic pain syndrome with unknown etiology and a wide spectrum of symptoms such as allodynia, debilitating fatigue, joint stiffness and migraine. Recent studies have shown some evidences demonstrating that oxidative stress is associated to clinical symptoms in FM of fibromyalgia. We examined oxidative stress and bioenergetic status in blood mononuclear cells (BMCs) and its association to headache symptoms in FM patients. The effects of oral coenzyme Q10 (CoQ10) supplementation on biochemical markers and clinical improvement were also evaluated. Methods We studied 20 FM patients and 15 healthy controls. Clinical parameters were evaluated using the Fibromyalgia Impact Questionnaire (FIQ), visual analogues scales (VAS), and the Headache Impact Test (HIT-6). Oxidative stress was determined by measuring CoQ10, catalase and lipid peroxidation (LPO) levels in BMCs. Bioenergetic status was assessed by measuring ATP levels in BMCs. Results We found decreased CoQ10, catalase and ATP levels in BMCs from FM patients as compared to normal control (P<0.05 and P<0.001, respectively) We also found increased level of LPO in BMCs from FM patients as compared to normal control (P<0.001). Significant negative correlations between CoQ10 or catalase levels in BMCs and headache parameters were observed (r = −0.59, P<0.05; r = −0.68, P<0.05, respectively). Furthermore, LPO levels showed a significant positive correlation with HIT-6 (r = 0.33, P<0.05). Oral CoQ10 supplementation restored biochemical parameters and induced a significant improvement in clinical and headache symptoms (P<0.001). Discussion The results of this study suggest a role for mitochondrial dysfunction and oxidative stress in the headache symptoms associated with FM. CoQ10 supplementation should be examined in a larger placebo controlled trial as a possible treatment in FM. PMID:22532869

Oxidative stress correlates with headache symptoms in fibromyalgia: coenzyme Q₁₀ effect on clinical improvement.

PubMed

Cordero, Mario D; Cano-García, Francisco Javier; Alcocer-Gómez, Elísabet; De Miguel, Manuel; Sánchez-Alcázar, José Antonio

2012-01-01

Fibromyalgia (FM) is a chronic pain syndrome with unknown etiology and a wide spectrum of symptoms such as allodynia, debilitating fatigue, joint stiffness and migraine. Recent studies have shown some evidences demonstrating that oxidative stress is associated to clinical symptoms in FM of fibromyalgia. We examined oxidative stress and bioenergetic status in blood mononuclear cells (BMCs) and its association to headache symptoms in FM patients. The effects of oral coenzyme Q(10) (CoQ(10)) supplementation on biochemical markers and clinical improvement were also evaluated. We studied 20 FM patients and 15 healthy controls. Clinical parameters were evaluated using the Fibromyalgia Impact Questionnaire (FIQ), visual analogues scales (VAS), and the Headache Impact Test (HIT-6). Oxidative stress was determined by measuring CoQ(10), catalase and lipid peroxidation (LPO) levels in BMCs. Bioenergetic status was assessed by measuring ATP levels in BMCs. We found decreased CoQ(10), catalase and ATP levels in BMCs from FM patients as compared to normal control (P < 0.05 and P < 0.001, respectively) We also found increased level of LPO in BMCs from FM patients as compared to normal control (P < 0.001). Significant negative correlations between CoQ(10) or catalase levels in BMCs and headache parameters were observed (r  = -0.59, P < 0.05; r  =  -0.68, P < 0.05, respectively). Furthermore, LPO levels showed a significant positive correlation with HIT-6 (r = 0.33, P<0.05). Oral CoQ(10) supplementation restored biochemical parameters and induced a significant improvement in clinical and headache symptoms (P < 0.001). The results of this study suggest a role for mitochondrial dysfunction and oxidative stress in the headache symptoms associated with FM. CoQ10 supplementation should be examined in a larger placebo controlled trial as a possible treatment in FM.

Plasma homocysteine is associated with increased oxidative stress and antioxidant enzyme activity in welders.

PubMed

Liu, Hung-Hsin; Shih, Tung-Sheng; Huang, Hsin-Ru; Huang, Shih-Chien; Lee, Lien-Hsiung; Huang, Yi-Chia

2013-01-01

The purpose of this study was to examine the association of vitamin B6 status and plasma homocysteine with oxidative stress and antioxidant capacities in welders. Workers were divided into either the welding exposure group (n = 57) or the nonexposure controls (n = 42) based on whether they were employed as welders. There were no significant differences in vitamin B₆ status and plasma homocysteine concentration between the welding exposure group and the nonexposure controls. The welding exposure group had significantly higher levels of oxidized low-density lipoprotein cholesterol and lower erythrocyte glutathione concentration and superoxide dismutase (SOD) activities when compared to nonexposure controls. Plasma pyridoxal 5'-phosphate concentration did not correlate with oxidative stress indicators or antioxidant capacities in either group. However, plasma homocysteine significantly correlated with total antioxidant capacity (TAC) (partial r(s) = -0.34, P < 0.05) and erythrocyte SOD activities (partial r(s) = 0.29, P < 0.05) after adjusting for potential confounders in the welding exposure group. In the welding exposure group, adequate vitamin B₆ status was not associated with oxidative stress or antioxidant capacities. However, elevated plasma homocysteine seemed to be a major contributing factor to antioxidant capacities (TAC and erythrocyte SOD activities) in welders.

Identification of a Methane Oxidation Intermediate on Solid Oxide Fuel Cell Anode Surfaces with Fourier Transform Infrared Emission.

PubMed

Pomfret, Michael B; Steinhurst, Daniel A; Owrutsky, Jeffrey C

2013-04-18

Fuel interactions on solid oxide fuel cell (SOFC) anodes are studied with in situ Fourier transform infrared emission spectroscopy (FTIRES). SOFCs are operated at 800 °C with CH4 as a representative hydrocarbon fuel. IR signatures of gas-phase oxidation products, CO2(g) and CO(g), are observed while cells are under load. A broad feature at 2295 cm(-1) is assigned to CO2 adsorbed on Ni as a CH4 oxidation intermediate during cell operation and while carbon deposits are electrochemically oxidized after CH4 operation. Electrochemical control provides confirmation of the assignment of adsorbed CO2. FTIRES has been demonstrated as a viable technique for the identification of fuel oxidation intermediates and products in working SOFCs, allowing for the elucidation of the mechanisms of fuel chemistry.

Mesoporous metal oxides and processes for preparation thereof

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suib, Steven L.; Poyraz, Altug Suleyman

A process for preparing a mesoporous metal oxide, i.e., transition metal oxide. Lanthanide metal oxide, a post-transition metal oxide and metalloid oxide. The process comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to form the mesoporous metal oxide. A mesoporous metal oxide prepared by the above process. A method of controlling nano-sized wall crystallinity and mesoporosity in mesoporous metal oxides. The method comprises providing an acidic mixture comprising a metal precursor, an interface modifier,more » a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to control nano-sized wall crystallinity and mesoporosity in the mesoporous metal oxides. Mesoporous metal oxides and a method of tuning structural properties of mesoporous metal oxides.« less

Oxidation Through Coating Cracks of SiC-Protected Carbon/Carbon

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.; Roth, Don J.; Rauser, Richard W.; Cawley, James D.; Curry, Donald M.

2008-01-01

The oxidation of SiC-protected carbon/carbon through machined slots and naturally occurring craze cracks in the SiC was studied. The slot and crack geometries were characterized, and the subsurface oxidation of the carbon/carbon substrate at temperatures of 1000 to 1300 C in air was assessed using weight change, x-ray computed tomography, and optical microscopy of sections. Rate constants were derived from these measurements and compared with a two-step diffusion control model of carbon oxidation. Oxidation kinetic measurements on both the specimens with machined slots and with naturally occurring craze cracks showed good agreement with the model.

The oxidation of carbon monoxide using tin oxide based catalysts

NASA Technical Reports Server (NTRS)

Sampson, Christopher F.; Jorgensen, Norman

1990-01-01

The preparation conditions for precious metal/tin oxide catalysts were optimized for maximum carbon monoxide/oxygen recombination efficiency. This was achieved by controlling the tin digestion, the peptization to form the sol, the calcination process and the method of adding the precious metals. Extensive studies of the tin oxide structure were carried out over the temperature range 20 to 500 C in air or hydrogen environments using Raman scattering and X ray diffraction. Adsorbed species on tin oxide, generated in an environment containing carbon monoxide, gave rise to a Raman band at about 1600 cm(exp -1) which was assigned to carbonaceous groups, possible carbonate.

Oxidation Through Coating Cracks of SiC-Protected Carbon/Carbon

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.; Roth, Don J.; Rauser, Richard W.; Curry, Donald M.

2007-01-01

The oxidation of SiC-protected carbon/carbon through machined slots and naturally occurring craze cracks in the SiC was studied. The slot and crack geometries were characterized, and the subsurface oxidation of the carbon/carbon substrate at temperatures of 1000 to 1300 C in air was assessed using weight change, x-ray computed tomography, and optical microscopy of sections. Rate constants were derived from these measurements and compared with a two-step diffusion control model of carbon oxidation. Oxidation kinetic measurements on both the specimens with machined slots and with naturally occurring craze cracks showed good agreement with the model.

Nitric oxide-releasing indomethacin enhances susceptibility to Trypanosoma cruzi infection acting in the cell invasion and oxidative stress associated with anemia.

PubMed

Tatakihara, Vera Lucia Hideko; Malvezi, Aparecida Donizette; Panis, Carolina; Cecchini, Rubens; Zanluqui, Nagela Ghabdan; Yamauchi, Lucy Megumi; Martins, Maria Isabel Lovo; da Silva, Rosiane Valeriano; Yamada-Ogatta, Sueli Fumie; Rizzo, Luiz Vicente; Martins-Pinge, Marli Cardoso; Pinge-Filho, Phileno

2015-02-05

Trypanosoma cruzi is the causative agent of Chagas disease. Approximately 8 million people are thought to be affected with this disease worldwide. T. cruzi infection causes an intense inflammatory response, which is critical for the control of parasite proliferation and disease development. Nitric oxide-donating nonsteroidal anti-inflammatory drugs (NO-NSAIDs) are an emergent class of pharmaceutical derivatives with promising utility as chemopreventive agents. In this study, we investigated the effect of NO-indomethacin on parasite burden, cell invasion, and oxidative stress in erythrocytes during the acute phase of infection. NO-indomethacin was dissolved in dimethyl formamide followed by i.p. administration of 50 ppm into mice 30 min after infection with 5×10(3) blood trypomastigote forms (Y strain). The drug was administered every day until the animals died. Control animals received 100 μL of drug vehicle via the same route. Within the NO-indomethacin-treatment group, parasitemia and mortality (100%) were higher and oxidative stress in erythrocytes, anemia, and entry of parasites into macrophages were significantly greater than that seen in controls. Increase in the entry and survival of intracellular T. cruzi was associated with inhibition of nitric oxide production by macrophages treated with NO-indomethacin (2.5 μM). The results of this study provide strong evidence that NO-NSAIDs potently inhibit nitric oxide production, suggesting that NO-NSAID-based therapies against infections would be difficult to design and would require caution. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Association between plasma fluorescent oxidation products and erectile dysfunction: A prospective study.

PubMed

Yang, Shuman; Giovannucci, Edward; Bracken, Bruce; Ho, Shuk-Mei; Wu, Tianying

2015-08-14

Existing epidemiological studies of the association between oxidative stress and erectile dysfunction (ED) are sparse and inconclusive, which is likely due to cross-sectional design and small sample size. Therefore, we investigated the association between biomarkers of oxidative stress and ED in prospective setting among a relatively large sample size of men. We conducted the prospective study among 917 men ages between 47 and 80 years at the time of blood draw, which is a part of nested prospective case-control study of prostate cancer in the Health Professionals Follow-up Study. Plasma fluorescent oxidation products (FlOPs), a global biomarker for oxidative stress, were measured at three excitation/emission wavelengths (360/420 nm named as FlOP_360; 320/420 nm named as FlOP_320 and 400/475 nm named as FlOP_400). Approximately 35% of men developed ED during follow-up. We did not find an independent association between FlOP_360, FlOP_320, FlOP_400 and risk of ED in the multivariable adjusted model (Tertile 3 vs. tertile 1: odds ratio [OR] = 0.90, 95% confidence interval [CI] = 0.61-1.34, P(trend) = 0.54 for FlOP_360; OR = 0.73, 95% CI = 0.49-1.07, P(trend) = 0.27 for FlOP_320; and OR = 0.98, 95% CI = 0.66-1.45, P(trend) = 0.72 for FlOP_400). Further analysis of the association between FlOPs and ED in the fasting samples or controls only (free of prostate cancer incidence) did not change the results appreciably. Plasma FlOPs were not associated with the risk of ED, suggesting oxidative stress may not be an independent risk factor for ED.

Comparison of Total Antioxidant Capacity Oxidative Stress and Blood Lipoprotein Parameters in Volleyball Players and Sedentary

ERIC Educational Resources Information Center

Gokhan, Ismail

2013-01-01

This study aims to measure, then compare sedentary blood lipoproteins, oxidant- antioxidant state and oxidative stress index in volleyball players. The experimental group of the research consists of regularly practising 20 boys between the ages of 12 and 17, and the control group comprises 32 children practising no particular sports branch, 12 of…

Oxidative Damage to the Salivary Glands of Rats with Streptozotocin-Induced Diabetes-Temporal Study: Oxidative Stress and Diabetic Salivary Glands.

PubMed

Knaś, M; Maciejczyk, M; Daniszewska, I; Klimiuk, A; Matczuk, J; Kołodziej, U; Waszkiel, D; Ładny, J R; Żendzian-Piotrowska, M; Zalewska, A

2016-01-01

Objective. This study evaluated oxidative damage caused to the salivary glands in streptozotocin-induced diabetes (DM). Materials and Methods. Rats were divided into 4 groups: groups 1 and 2, control rats, and groups 3 and 4, DM rats. 8-Hydroxy-2'-deoxyguanosine (8-OHdG), protein carbonyl (PC), 4-hydroxynonenal protein adduct (4-HNE), oxidized and/or MDA-modified LDL-cholesterol (oxy-LDL/MDA), 8-isoprostanes (8-isoP), and oxidative stress index (OSI) were measured at 7 (groups 1 and 3) and 14 (groups 2 and 4) days of experiment. Results. The unstimulated salivary flow in DM rats was reduced in the 2nd week, while the stimulated flow was decreased throughout the duration of the experiment versus control. OSI was elevated in both diabetic glands in the 1st and 2nd week, whereas 8-isoP and 8-OHdG were higher only in the parotid gland in the second week. PC and 4-HNE were increased in the 1st and 2nd week, whereas oxy-LDL/MDA was increased in the 2nd week in the diabetic parotid glands. Conclusions. Diabetes induces oxidative damage of the salivary glands, which seems to be caused by processes taking place in the salivary glands, independently of general oxidative stress. The parotid glands are more vulnerable to oxidative damage in these conditions.

The relationship between leptin level and oxidative status parameters in hemodialysis patients.

PubMed

Horoz, Mehmet; Aslan, Mehmet; Koylu, Ahmet O; Bolukbas, Cengiz; Bolukbas, Filiz F; Selek, Sahbettin; Erel, Ozcan

2009-01-01

Both serum leptin level and oxidative stress are increased in hemodialysis (HD) patients. In the present study, we aimed to investigate whether there is association between oxidative status and leptin level in HD patients. Thirty-five HD patients and 25 healthy controls were enrolled in the present study. Serum leptin level, total peroxide (TP) level, total antioxidant capacity (TAC), and oxidative stress index (OSI) were determined. Serum leptin level, TP level, and OSI were significantly higher in HD patients than controls (all P < 0.001) while TAC was lower (P < 0.001). In HD patients, serum leptin level was significantly correlated with TP level and OSI (r = 0.372, P < 0.001 and r = 0.409, P < 0.001, respectively). The correlation of serum leptin level with TP level and OSI remained statistically significant after adjusting for age, gender, and body-fat percentage (r = 0.446, P < 0.001 and r = 0.463, P < 0.001, respectively). Hyperleptinemia seems to be associated with increased oxidative stress in HD patients, and this association may provide better understanding about the disorders related to either elevated serum leptin levels and/or increased oxidative stress in HD patients.

Chronic administration of fluoxetine or clozapine induces oxidative stress in rat liver: a histopathological study.

PubMed

Zlatković, Jelena; Todorović, Nevena; Tomanović, Nada; Bošković, Maja; Djordjević, Snežana; Lazarević-Pašti, Tamara; Bernardi, Rick E; Djurdjević, Aleksandra; Filipović, Dragana

2014-08-01

Chronic exposure to stress contributes to the etiology of mood disorders, and the liver as a target organ of antidepressant and antipsychotic drug metabolism is vulnerable to drug-induced toxicity. We investigated the effects of chronic administration of fluoxetine (15mg/kg/day) or clozapine (20mg/kg/day) on liver injury via the measurement of liver enzymes, oxidative stress and histopathology in rats exposed to chronic social isolation (21days), an animal model of depression, and controls. The activity of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), the liver content of carbonyl groups, malonyldialdehyde (MDA), reduced glutathione (GSH), cytosolic glutathione S-transferase (GST) and nitric oxide (NO) metabolites were determined. We also characterized nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2) and CuZn-superoxide dismutase (CuZnSOD) protein expression as well as histopathological changes. Increased serum ALT activity in chronically-isolated and control animals treated with both drugs was found while increased AST activity was observed only in fluoxetine-treated rats (chronically-isolated and controls). Increased carbonyl content, MDA, GST activity and decreased GSH levels in drug-treated controls/chronically-isolated animals suggest a link between drugs and hepatic oxidative stress. Increased NO levels associated with NF-κB activation and the concomitant increased COX-2 expression together with compromised CuZnSOD expression in clozapine-treated chronically-isolated rats likely reinforce oxidative stress, observed by increased lipid peroxidation and GSH depletion. In contrast, fluoxetine reduced NO levels in chronically-isolated rats. Isolation induced oxidative stress but histological changes were similar to those observed in vehicle-treated controls. Chronic administration of fluoxetine in both chronically-isolated and control animals resulted in more or less normal hepatic architecture, while clozapine in both groups resulted in liver injury. These data suggest that clozapine appears to have a higher potential to induce liver toxicity than fluoxetine. Copyright © 2014 Elsevier B.V. All rights reserved.

Alpha-tocopherol and alpha-tocopheryl quinone levels in cervical intraepithelial neoplasia and cervical cancer.

PubMed

Palan, Prabhudas R; Woodall, Angela L; Anderson, Patrick S; Mikhail, Magdy S

2004-05-01

alpha-Tocopherol is a potent antioxidant that protects cell membranes against oxidative damage. Red blood cell alpha-tocopherol levels reflect membrane alpha-tocopherol concentrations, and altered levels may suggest membrane damage. The objective of this study was to determine the levels of alpha-tocopherol and alpha-tocopheryl quinone, the oxidized product of alpha-tocopherol, in plasma and red blood cells that were obtained from control subjects and patients with cervical intraepithelial neoplasia and cervical cancer. In this cross-sectional study, 72 women, (32 African American and 40 Hispanic) were recruited. Among these subjects, 37 women had cervical intraepithelial neoplasia; 14 women had cervical cancer, and 21 women were considered control subjects, who had normal Papanicolaou test results. alpha-Tocopherol and alpha-tocopheryl quinone levels were determined in red blood cell and plasma by high-pressure liquid chromatography. Plasma levels of alpha-tocopherol and alpha-tocopheryl quinone were decreased significantly (P=.012 and=.005, respectively, by Kruskal-Wallis test) in study groups compared with the control group; red blood cell levels of alpha-tocopherol and alpha-tocopheryl quinone were not altered significantly. The lower alpha-tocopherol level that was observed in this study is consistent with our previous reports of decreased antioxidant concentrations and increased oxidative stress in women with cervical intraepithelial neoplasia. Unaltered red blood cell alpha-tocopherol and alpha-tocopheryl quinone levels suggest undamaged cell membrane. Further studies are needed to investigate the potential role of oxidative stress in cervical intraepithelial neoplasia.

Synergistic effect of sunlight induced photothermal conversion and H2O2 release based on hybridized tungsten oxide gel for cancer inhibition

NASA Astrophysics Data System (ADS)

Wang, Cong; Gao, Yibo; Gao, Xinghua; Wang, Hua; Tian, Jingxuan; Wang, Li; Zhou, Bingpu; Ye, Ziran; Wan, Jun; Wen, Weijia

2016-10-01

A highly efficient photochromic hydrogel was successfully fabricated via casting precursor, which is based on amorphous tungsten oxide and poly (ethylene oxide)-block-poly (propylene oxide)-block-poly (ethylene oxide). Under simulated solar illumination, the hydrogel has a rapid and controlled temperature increasing ratio as its coloration degree. Localized electrons in the amorphous tungsten oxide play a vital role in absorption over a broad range of wavelengths from 400 nm to 1100 nm, encompassing the entire visible light and infrared regions in the solar spectrum. More importantly, the material exhibits sustainable released H2O2 induced by localized electrons, which has a synergistic effect with the rapid surface temperature increase. The amount of H2O2 released by each film can be tuned by the light irradiation, and the film coloration can indicate the degree of oxidative stress. The ability of the H2O2-releasing gels in vitro study was investigated to induce apoptosis in melanoma tumor cells and NIH 3T3 fibroblasts. The in vivo experimental results indicate that these gels have a greater healing effect than the control in the early stages of tumor formation.

Synergistic effect of sunlight induced photothermal conversion and H2O2 release based on hybridized tungsten oxide gel for cancer inhibition

PubMed Central

Wang, Cong; Gao, Yibo; Gao, Xinghua; Wang, Hua; Tian, Jingxuan; Wang, Li; Zhou, Bingpu; Ye, Ziran; Wan, Jun; Wen, Weijia

2016-01-01

A highly efficient photochromic hydrogel was successfully fabricated via casting precursor, which is based on amorphous tungsten oxide and poly (ethylene oxide)-block-poly (propylene oxide)-block-poly (ethylene oxide). Under simulated solar illumination, the hydrogel has a rapid and controlled temperature increasing ratio as its coloration degree. Localized electrons in the amorphous tungsten oxide play a vital role in absorption over a broad range of wavelengths from 400 nm to 1100 nm, encompassing the entire visible light and infrared regions in the solar spectrum. More importantly, the material exhibits sustainable released H2O2 induced by localized electrons, which has a synergistic effect with the rapid surface temperature increase. The amount of H2O2 released by each film can be tuned by the light irradiation, and the film coloration can indicate the degree of oxidative stress. The ability of the H2O2-releasing gels in vitro study was investigated to induce apoptosis in melanoma tumor cells and NIH 3T3 fibroblasts. The in vivo experimental results indicate that these gels have a greater healing effect than the control in the early stages of tumor formation. PMID:27775086

Comparative Study of Surface Chemical Composition and Oxide Layer Modification upon Oxygen Plasma Cleaning and Piranha Etching on a Novel Low Elastic Modulus Ti25Nb21Hf Alloy

NASA Astrophysics Data System (ADS)

Paredes, Virginia; Salvagni, Emiliano; Rodríguez-Castellón, Enrique; Manero, José María

2017-08-01

Metals are widely employed for many biological artificial replacements, and it is known that the quality and the physical/chemical properties of the surface are crucial for the success of the implant. Therefore, control over surface implant materials and their elastic moduli may be crucial to avoid undesired effects. In this study, surface modification upon cleaning and activation of a low elastic modulus Ti alloy (Ti25Hf21Nb) was investigated. Two different methods, oxygen plasma (OP) cleaning and piranha (PI) solution, were studied and compared. Both surface treatments were effective for organic contaminant removal and to increase the Ti-oxide layer thickness rather than other metal-oxides present at the surface, which is beneficial for biocompatibility of the material. Furthermore, both techniques drastically increased hydrophilicity and introduced oxidation and hydroxylation (OH)-functional groups at the surface that may be beneficial for further chemical modifications. However, these treatments did not alter the surface roughness and bulk material properties. The surfaces were fully characterized in terms of surface roughness, wettability, oxide layer composition, and hydroxyl surface density through analytical techniques (interferometry, X-ray photoelectron spectroscopy (XPS), contact angle, and zinc complexation). These findings provide essential information when planning surface modifications for cleanliness, oxide layer thickness, and surface hydroxyl density, as control over these factors is essential for many applications, especially in biomaterials.

Association of erythrocytes antioxidant enzymes and their cofactors with markers of oxidative stress in patients with sickle cell anemia.

PubMed

Al-Naama, Lamia M; Hassan, Mea'ad K; Mehdi, Jawad K

2015-01-01

Sickle cell anemia (SCA) is an inherited blood disease with known complications as a result of certain pathophysiological dysfunctions. It has been suggested that an increase in oxidative stress contributes to the incidence of these changes. This study investigated the oxidant/antioxidant status of patients with SCA, and evaluated the effect of SCA on antioxidant enzymes and their cofactors. The study included 42 patients with SCA (in steady state), and a control group of 50 age-matched individuals without SCA. Serum malondialdehyde (MDA), copper, zinc, ferritin and iron levels, red blood cell (RBC) superoxide dismutase (SOD) and catalase levels were measured for the SCA and control groups. Significantly lower levels of antioxidant enzymes (RBC SOD and catalase) and higher serum MDA levels (biomarker of oxidative stress) were found in SCA patients compared to the control group (all p < 0.001). Increased levels of serum ferritin, iron and copper and decreased zinc concentrations were also found in the SCA patients compared to the control group (all p < 0.001). In the SCA group, there were significant negative correlations between MDA levels and RBC SOD, RBC catalase, and serum zinc levels (p < 0.01), while a significant positive correlation between MDA with serum copper and iron levels (p < 0.01) was observed. SCA is associated with alterations in markers of oxidative stress including an increased MDA level, decreased antioxidant enzyme levels, and altered levels of enzyme cofactors (zinc, copper, and iron). This suggests that these antioxidant enzymes could be used as effective therapeutic targets for the treatment of this disease and supplementation of patients with substances with antioxidant properties may reduce the complications of this disease.

A systematic review of observational studies on oxidative/nitrosative stress involvement in dengue pathogenesis

PubMed Central

Pinzón, Hernando Samuel; Alvis-Guzman, Nelson

2015-01-01

Objective: Our objective was to systematically review the published observational research related to the role of oxidative-nitrosative stress in pathogenesis of dengue. Methods: We searched electronic databases (PubMed, EMBASE, The COCHRANE library, ScienceDirect, Scopus, SciELO, LILACS via Virtual Health Library, Google Scholar) using the term: dengue, dengue virus, severe dengue, oxidative stress, nitrosative stress, antioxidants, oxidants, free radicals, oxidized lipid products, lipid peroxides, nitric oxide, and nitric oxide synthase. Articles were selected for review by title and abstract excluding letter, review, in vivo and in vitro studies, and duplicates studies. Selected articles were reviewed for study design, original purposes, sample size, main outcomes, methods, and oxidative-nitrosative stress markers values. Results: In total, 4,331 non-duplicates articles were identified from electronic databases searches, of which 16 were eligible for full text searching. Data from the observational studies originate from Asian countries (50%; 8/16), South American countries (31.2%; 5/16), and Central America and the Caribbean countries (18.8%; 3/16). Case-control study was the type of design most common in researches reviewed. The 1997 World Health Organization (WHO) dengue case classification criteria were used in all studies included in this review. Conclusions: Based on published data found in peer-reviewed literature, oxidative and nitrosative stress are demonstrated by changes in plasma levels of nitric oxide, antioxidants, lipid peroxidation and protein oxidation markers in patients with dengue infection. Additionally, elevated serum protein carbonyls and malondialdehyde levels appear to be associated with dengue disease severity. PMID:26600629

The protective effect of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes.

PubMed

Mohamed, Jamaludin; Shing, Saw Wuan; Idris, Muhd Hanis Md; Budin, Siti Balkis; Zainalabidin, Satirah

2013-10-01

The aim of this study was to investigate the protective effects of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell (RBC) membrane oxidative stress in rats with streptozotocin-induced diabetes. Forty male Sprague-Dawley rats weighing 230-250 g were randomly divided into four groups (n = 10 rats each): control group (N), roselle-treated control group, diabetic group, and roselle-treated diabetic group. Roselle was administered by force-feeding with aqueous extracts of roselle (100 mg/kg body weight) for 28 days. The results demonstrated that the malondialdehyde levels of the red blood cell membranes in the diabetic group were significantly higher than the levels in the roselle-treated control and roselle-treated diabetic groups. The protein carbonyl level was significantly higher in the roselle-treated diabetic group than in the roselle-treated control group but lower than that in the diabetic group. A significant increase in the red blood cell membrane superoxide dismutase enzyme was found in roselle-treated diabetic rats compared with roselle-treated control rats and diabetic rats. The total protein level of the red blood cell membrane, osmotic fragility, and red blood cell morphology were maintained. The present study demonstrates that aqueous extracts of roselle possess a protective effect against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes. These data suggest that roselle can be used as a natural antioxidative supplement in the prevention of oxidative damage in diabetic patients.

The protective effect of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes

PubMed Central

Mohamed, Jamaludin; Shing, Saw Wuan; Md Idris, Muhd Hanis; Budin, Siti Balkis; Zainalabidin, Satirah

2013-01-01

OBJECTIVES: The aim of this study was to investigate the protective effects of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell (RBC) membrane oxidative stress in rats with streptozotocin-induced diabetes. METHODS: Forty male Sprague-Dawley rats weighing 230-250 g were randomly divided into four groups (n = 10 rats each): control group (N), roselle-treated control group, diabetic group, and roselle-treated diabetic group. Roselle was administered by force-feeding with aqueous extracts of roselle (100 mg/kg body weight) for 28 days. RESULTS: The results demonstrated that the malondialdehyde levels of the red blood cell membranes in the diabetic group were significantly higher than the levels in the roselle-treated control and roselle-treated diabetic groups. The protein carbonyl level was significantly higher in the roselle-treated diabetic group than in the roselle-treated control group but lower than that in the diabetic group. A significant increase in the red blood cell membrane superoxide dismutase enzyme was found in roselle-treated diabetic rats compared with roselle-treated control rats and diabetic rats. The total protein level of the red blood cell membrane, osmotic fragility, and red blood cell morphology were maintained. CONCLUSION: The present study demonstrates that aqueous extracts of roselle possess a protective effect against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes. These data suggest that roselle can be used as a natural antioxidative supplement in the prevention of oxidative damage in diabetic patients. PMID:24212844

Size-dependent electronic structure controls activity for ethanol electro-oxidation at Ptn/indium tin oxide (n = 1 to 14).

PubMed

von Weber, Alexander; Baxter, Eric T; Proch, Sebastian; Kane, Matthew D; Rosenfelder, Michael; White, Henry S; Anderson, Scott L

2015-07-21

Understanding the factors that control electrochemical catalysis is essential to improving performance. We report a study of electrocatalytic ethanol oxidation - a process important for direct ethanol fuel cells - over size-selected Pt centers ranging from single atoms to Pt14. Model electrodes were prepared by soft-landing of mass-selected Ptn(+) on indium tin oxide (ITO) supports in ultrahigh vacuum, and transferred to an in situ electrochemical cell without exposure to air. Each electrode had identical Pt coverage, and differed only in the size of Pt clusters deposited. The small Ptn have activities that vary strongly, and non-monotonically with deposited size. Activity per gram Pt ranges up to ten times higher than that of 5 to 10 nm Pt particles dispersed on ITO. Activity is anti-correlated with the Pt 4d core orbital binding energy, indicating that electron rich clusters are essential for high activity.

Asymmetric dimethylarginine in somatically healthy schizophrenia patients treated with atypical antipsychotics: a case-control study.

PubMed

Jorgensen, Anders; Knorr, Ulla; Soendergaard, Mia Greisen; Lykkesfeldt, Jens; Fink-Jensen, Anders; Poulsen, Henrik Enghusen; Jorgensen, Martin Balslev; Olsen, Niels Vidiendal; Staalsø, Jonatan Myrup

2015-04-03

Schizophrenia is associated with increased cardiovascular morbidity and mortality. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of the nitric oxide synthase, and the L-arginine:ADMA ratio are markers of endothelial dysfunction that predict mortality and adverse outcome in a range of cardiovascular disorders. Increased ADMA levels may also lead to increased oxidative stress. We hypothesized that ADMA and the L-arginine:ADMA ratio are increased in somatically healthy schizophrenia patients treated with atypical antipsychotics (AAP), and that the ADMA and the L-arginine: ADMA ratio are positively correlated to measures of oxidative stress. We included 40 schizophrenia patients treated with AAP, but without somatic disease or drug abuse, and 40 healthy controls. Plasma concentrations of ADMA and L-arginine were determined by high-performance liquid chromatography. Data were related to markers of systemic oxidative stress on DNA, RNA and lipids, as well as measures of medication load, duration of disease and current symptomatology. Plasma ADMA and the L-arginine:ADMA ratio did not differ between schizophrenia patients and controls. Furthermore, ADMA and the L-arginine:ADMA ratio showed no correlations with oxidative stress markers, medication load, or Positive and Negative Syndrome Scale scores. Schizophrenia and treatment with AAP was not associated with increased levels of plasma ADMA or the L-arginine:ADMA ratio. Furthermore, plasma levels of ADMA were not associated with levels of systemic oxidative stress in vivo.

Maternal active or passive smoking causes oxidative stress in placental tissue.

PubMed

Aycicek, Ali; Varma, Mustafa; Ahmet, Koc; Abdurrahim, Kocyigit; Erel, Ozcan

2011-05-01

The aim of this study was to assess the influence of active and passive maternal smoking on placenta total oxidant/antioxidant status in term infants. The levels of cord blood total antioxidant capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) were measured in samples of fetal placental tissue, cord blood, and the maternal peripheral blood serum and from 19 mothers who were active smokers, 19 who were passive smokers, and 22 who were nonsmokers (not exposed to active or passive smoking). The pregnancies were between 37 and 40 weeks' gestation, were uncomplicated, and the infants were delivered vaginally. Birth weight and head circumference in the active smokers were significantly (P < 0.001) lower than those in the controls. Placenta, cord blood, and the maternal peripheral TAC levels were significantly lower in the active smokers compared with the controls (P < 0.001), while TOS and OSI levels were significantly higher in the active and passive smokers than in the controls (P < 0.001). A positive significant correlation was found between active maternal smoking and placenta TOS and OSI levels (P < 0.016), and a significant negative correlation was found between number of cigarettes exposed to and birthweight and head circumference (P < 0.05). In conclusion, active or passive maternal smoking is associated with important alterations in oxidant and antioxidant balance in fetal placental tissue and causes potent oxidative stress.

Oxidative stress of crystalline lens in rat menopausal model.

PubMed

Acer, Semra; Pekel, Gökhan; Küçükatay, Vural; Karabulut, Aysun; Yağcı, Ramazan; Çetin, Ebru Nevin; Akyer, Şahika Pınar; Şahin, Barbaros

2016-01-01

To evaluate lenticular oxidative stress in rat menopausal models. Forty Wistar female albino rats were included in this study. A total of thirty rats underwent oophorectomy to generate a menopausal model. Ten rats that did not undergo oophorectomy formed the control group (Group 1). From the rats that underwent oophorectomy, 10 formed the menopause control group (Group 2), 10 were administered a daily injection of methylprednisolone until the end of the study (Group 3), and the remaining 10 rats were administered intraperitoneal streptozocin to induce diabetes mellitus (Group 4). Total oxidant status (TOS), total antioxidant capacity (TAC), and oxidative stress index (OSI) measurements of the crystalline lenses were analyzed. The mean OSI was the lowest in group 1 and highest in group 4. Nevertheless, the difference between the groups was not statistically significant in terms of OSI (p >0.05). The mean TOS values were similar between the groups (p >0.05), whereas the mean TAC of group 1 was significantly higher than that of the other groups (p <0.001). Our results indicate that menopause may not promote cataract formation.

Inhibitory effect of three C-glycosylflavonoids from Cymbopogon citratus (Lemongrass) on human low density lipoprotein oxidation.

PubMed

Orrego, Roxana; Leiva, Elba; Cheel, José

2009-09-30

This study assessed the inhibitory effect of three C-glycosylflavonoids from Cymbopogon citratus leaves--isoorientin (1), swertiajaponin (2) and isoorientin 2"-Orhamnoside (3)--on human LDL oxidation. Isolated LDL was incubated with compounds 1-3 and the kinetics of lipid peroxidation were assessed by conjugated diene and malondialdehyde-thiobarbituric acid reactive substances (MDA-TBARS) formation after addition of copper ions. Significant differences (p < 0.05) between the lag time phase of the control and the lag time phase in the presence of the compounds 1 (0.25 microM) and 2 (0.50 microM) were observed. After five hours of incubation all three compounds showed a significant inhibitory effect on MDA-TBARS formation with respect to the control. After six hours of incubation only compound 1 kept a remarkable antioxidant effect. This study demonstrates that isoorientin (1) is an effective inhibitor of in vitro LDL oxidation. As oxidative damage to LDL is a key event in the formation of atherosclerotic lesions, the use of this natural antioxidant may be beneficial to prevent or attenuate atherosclerosis.

Lack of Association between Nuclear Factor Erythroid-Derived 2-Like 2 Promoter Gene Polymorphisms and Oxidative Stress Biomarkers in Amyotrophic Lateral Sclerosis Patients

PubMed Central

Chico, Lucia; Borgia, Loredana; Rocchi, Anna; D'Amelio, Antonia; Carlesi, Cecilia; Mancuso, Michelangelo; Siciliano, Gabriele

2014-01-01

Oxidative stress involvement has been strongly hypothesized among the possible pathogenic mechanisms of motor neuron degeneration in amyotrophic lateral sclerosis (ALS). The intracellular redox balance is finely modulated by numerous complex mechanisms critical for cellular functions, among which the nuclear factor erythroid-derived 2-like 2 (NFE2L2/Nrf2) pathways. We genotyped, in a cohort of ALS patients (n = 145) and healthy controls (n = 168), three SNPs in Nrf2 gene promoter: −653 A/G, −651 G/A, and −617 C/A and evaluated, in a subset (n = 73) of patients, advanced oxidation protein products (AOPP), iron-reducing ability of plasma (FRAP), and plasma thiols (-SH) as oxidative damage peripheral biomarkers. Nrf2 polymorphisms were not different among patients and controls. Increased levels of AOPP (P < 0.05) and decreased levels of FRAP (P < 0.001) have been observed in ALS patients compared with controls, but no difference in -SH values was found. Furthermore, no association was found between biochemical markers of redox balance and Nrf2 polymorphisms. These data confirm an altered redox balance in ALS and indicate that, while being abnormally modified compared to controls, the oxidative stress biomarkers assessed in this study are independent from the −653 A/G, −651 G/A, and −617 C/A Nrf2 SNPs in ALS patients. PMID:24672634

In vivo systemic chlorogenic acid therapy under diabetic conditions: Wound healing effects and cytotoxicity/genotoxicity profile.

PubMed

Bagdas, Deniz; Etoz, Betul Cam; Gul, Zulfiye; Ziyanok, Sedef; Inan, Sevda; Turacozen, Ozge; Gul, Nihal Yasar; Topal, Ayse; Cinkilic, Nilufer; Tas, Sibel; Ozyigit, Musa Ozgur; Gurun, Mine Sibel

2015-07-01

Oxidative stress occurs following the impairment of pro-oxidant/antioxidant balance in chronic wounds and leads to harmful delays in healing progress. A fine balance between oxidative stress and endogenous antioxidant defense system may be beneficial for wound healing under redox control. This study tested the hypothesis that oxidative stress in wound area can be controlled with systemic antioxidant therapy and therefore wound healing can be accelerated. We used chlorogenic acid (CGA), a dietary antioxidant, in experimental diabetic wounds that are characterized by delayed healing. Additionally, we aimed to understand possible side effects of CGA on pivotal organs and bone marrow during therapy. Wounds were created on backs of streptozotocin-induced diabetic rats. CGA (50 mg/kg/day) was injected intraperitoneally. Animals were sacrificed on different days. Biochemical and histopathological examinations were performed. Side effects of chronic antioxidant treatment were tested. CGA accelerated wound healing, enhanced hydroxyproline content, decreased malondialdehyde/nitric oxide levels, elevated reduced-glutathione, and did not affect superoxide dismutase/catalase levels in wound bed. While CGA induced side effects such as cyto/genotoxicity, 15 days of treatment attenuated blood glucose levels. CGA decreased lipid peroxidation levels of main organs. This study provides a better understanding for antioxidant intake on diabetic wound repair and possible pro-oxidative effects. Copyright © 2015 Elsevier Ltd. All rights reserved.

Oxidative stress in normal and diabetic rats.

PubMed

Torres, M D; Canal, J R; Pérez, C

1999-01-01

Parameters related to oxidative stress were studied in a group of 10 Wistar diabetic rats and 10 control rats. The levels of total erythrocyte catalase activity in the diabetic animals were significantly (p<0.001) greater than the control levels. The diabetic animals presented an amount of vitamin E far greater (p<0.0001) than the controls, as was also the case for the vitaminE/polyunsaturated fatty acid (PUFA) and vitaminE/linoleic acid (C18:2) ratios. Greater vitaminE/triglyceride (TG) ratio, however, appeared in the control group. The corresponding vitamin A ratios (vitaminA/TG, vitaminA/PUFA, vitaminA/C 18:2) were higher in the control group. Our work corroborates the findings that fatty acid metabolism presents alterations in the diabetes syndrome and that the antioxidant status is affected.

Rapid and controllable perforation of carbon nanotubes by microwave radiation

NASA Astrophysics Data System (ADS)

Ojaghi, Neda; Mokhtarifar, Maryam; Sabaghian, Zahra; Arab, Hamed; Maghrebi, Morteza; Baniadam, Majid

2018-05-01

This study presents a new controlled approach to deep perforation of millimeter-long carbon nanotube arrays (CNTAs) by fast oxidative cutting. The approach is based on decorating CNTAs with silver (Ag) nanoparticles, followed by heating Ag-decorated CNTAs with microwave radiation (2.48 GHz, 300 W). The perforation was evaluated using different techniques such as transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller method. The results of the oxidation of carbonaceous materials indicated that the relative amount of oxygen functional groups increased without total oxidation of carbon up to 60 s. After 60 s, the amount of functional groups decreased as the total oxidation started suddenly. Afterwards, at around 120 and 420 s, the oxidation of Ag-decorated CNTAs reached the point of total perforation and total cutting, respectively. Though carbon decomposition terminated at around 420 s, the total pore volume and surface area increased continuously. This was attributed to the steady growth of Ag nanoparticles located between CNTAs.

Enhancing mercury removal across air pollution control devices for coal-fired power plants by desulfurization wastewater evaporation.

PubMed

Bin, Hu; Yang, Yi; Cai, Liang; Yang, Linjun; Roszak, Szczepan

2017-10-09

Desulfurization wastewater evaporation technology is used to enhance the removal of gaseous mercury (Hg) in conventional air pollution control devices (APCDs) for coal-fired power plants. Studies have affirmed that gaseous Hg is oxidized and removed by selective catalytic reduction (SCR), an electrostatic precipitator (ESP) and wet flue gas desulfurization (WFGD) in a coal-fired thermal experiment platform with WFGD wastewater evaporation. Effects of desulfurization wastewater evaporation position, evaporation temperature and chlorine ion concentration on Hg oxidation were studied as well. The Hg 0 oxidation efficiency was increased ranging from 30% to 60%, and the gaseous Hg removal efficiency was 62.16% in APCDs when wastewater evaporated before SCR. However, the Hg 0 oxidation efficiency was 18.99% and the gaseous Hg removal efficiency was 40.19% in APCDs when wastewater evaporated before ESP. The results show that WFGD wastewater evaporation before SCR is beneficial to improve the efficiency of Hg oxidized and removed in APCDs. Because Hg 2+ can be easily removed in ACPDs and WFGD wastewater in power plants is enriched with chlorine ions, this method realizes WFGD wastewater zero discharge and simultaneously enhances Hg removal in APCDs.

Augmenting in vitro osteogenesis of a glycine-arginine-glycine-aspartic-conjugated oxidized alginate-gelatin-biphasic calcium phosphate hydrogel composite and in vivo bone biogenesis through stem cell delivery.

PubMed

Linh, Nguyen Tb; Paul, Kallyanashis; Kim, Boram; Lee, Byong-Taek

2016-11-01

A functionally modified peptide-conjugated hydrogel system was fabricated with oxidized alginate/gelatin loaded with biphasic calcium phosphate to improve its biocompatibility and functionality. Sodium alginate was treated by controlled oxidation to transform the cis-diol group into an aldehyde group in a controlled manner, which was then conjugated to the amine terminus of glycine-arginine-glycine-aspartic. Oxidized alginate glycine-arginine-glycine-aspartic was then combined with gelatin-loaded biphasic calcium phosphate to form a hydrogel of composite oxidized alginate/gelatin/biphasic calcium phosphate that displayed enhanced human adipose stem cell adhesion, spreading and differentiation. 1 H nuclear magnetic resonance and electron spectroscopy for chemical analysis confirmed that the glycine-arginine-glycine-aspartic was successfully grafted to the oxidized alginate. Co-delivery of glycine-arginine-glycine-aspartic and human adipose stem cell in a hydrogel matrix was studied with the results indicating that hydrogel incorporated modified with glycine-arginine-glycine-aspartic and seeded with human adipose stem cell enhanced osteogenesis in vitro and bone formation in vivo. © The Author(s) 2016.

DNA damage, DNA susceptibility to oxidation and glutathione redox status in patients with Alzheimer's disease treated with and without memantine.

PubMed

Akkaya, Çağlayan; Yavuzer, Serap Sahin; Yavuzer, Hakan; Erkol, Gökhan; Bozluolcay, Melda; Dinçer, Yıldız

2017-07-15

The aim of the current study was to compare oxidative DNA damage, DNA susceptibility to oxidation, and ratio of GSH/GSSG in patients with Alzheimer's disease (AD) treated with acetylcholinesterase inhibitor (AChEI) and combined AChEI+memantine. The study included 67 patients with AD and 42 volunteers as control. DNA damage parameters (strand breaks, oxidized purines, H 2 O 2 -induced DNA damage) in lymphocyte DNA and GSH/GSSG ratio in erythrocytes were determined by the comet assay and spectrophotometric assay, respectively. DNA damage was found to be higher, GSH/GSSG ratio was found to be lower in the AD group than those in the control group. DNA strand breaks and H 2 O 2 -induced DNA damage were lower in the patients taking AChEI+memantine than those in the patients taking AChEI but no significant difference was determined between the groups for oxidized purines and GSH/GSSG ratio. In conclusion, increased systemic oxidative DNA damage and DNA susceptibility to oxidation may be resulted from diminished GSH/GSSG ratio in AD patients. Although DNA strand breaks and H 2 O 2 -induced DNA damage are lower in the AD patients treated with combined AChEI and memantine, this may not indicate protective effect of memantine against DNA oxidation due to similar levels of oxidized purines in the patients treated with AChEI and AChEI+memantine. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment of Control Techniques for Reducing Emissions from Locomotive Engines

DOT National Transportation Integrated Search

1973-04-01

The primary objective of this study was to determine the most effective method of reducing emissions of oxides of nitrogen from a two-cylinder version of an EMD series 567C locomotive engine. The NOx control techniques selected for use in this study ...

V6O13 films by control of the oxidation state from aqueous precursor to crystalline phase.

PubMed

Peys, Nick; Ling, Yun; Dewulf, Daan; Gielis, Sven; De Dobbelaere, Christopher; Cuypers, Daniel; Adriaensens, Peter; Van Doorslaer, Sabine; De Gendt, Stefan; Hardy, An; Van Bael, Marlies K

2013-01-28

An aqueous deposition process for V(6)O(13) films is developed whereby the vanadium oxidation state is continuously controlled throughout the entire process. In the precursor stage, a controlled wet chemical reduction of the vanadium(V) source with oxalic acid is achieved and monitored by (51)Vanadium Nuclear Magnetic Resonance ((51)V-NMR) and Ultraviolet-Visible (UV-Vis) spectroscopy. The resulting vanadium(IV) species in the aqueous solution are identified as mononuclear citrato-oxovanadate(IV) complexes by Electron Paramagnetic Resonance (EPR) and Fourier Transform Infra-Red (FTIR) spectroscopy. This precursor is successfully employed for the deposition of uniform, thin films. The optimal deposition and annealing conditions for the formation of crystalline V(6)O(13), including the control of the vanadium oxidation state, are determined through an elaborate study of processing temperature and O(2) partial pressure. To ensure a sub 100 nm adjustable film thickness, a non-oxidative intermediate thermal treatment is carried out at the end of each deposition cycle, allowing maximal precursor decomposition while still avoiding V(IV) oxidation. The resulting surface hydrophilicity, indispensable for the homogeneous deposition of the next layer, is explained by an increased surface roughness and the increased availability of surface vanadyl groups. Crystalline V(6)O(13) with a preferential (002) orientation is obtained after a post deposition annealing in a 0.1% O(2) ambient for thin films with a thickness of 20 nm.

Processes of nickel and cobalt uptake by a manganese oxide forming sediment in Pinal Creek, Globe mining district, Arizona

USGS Publications Warehouse

Kay, J.T.; Conklin, M.H.; Fuller, C.C.; O'Day, P. A.

2001-01-01

A series of column experiments was conducted using manganese oxide coated sediments collected from the hyporheic zone in Pinal Creek (AZ), a metal-contaminated stream, to study the uptake and retention of Mn, Ni, and Co. Experimental variables included the absence (abiotic) and presence (biotic) of active Mn-oxidizing bacteria, the absence and presence of dissolved Mn, and sediment manganese oxide content. Uptake of Mn under biotic conditions was between 8 and 39% higher than under abiotic conditions. Continuous uptake of Mn due to biotic oxidation was evident from extraction of column sediments. Manganese uptake is hypothesized to initially occur as adsorption, which led to subsequent surface and/or microbial oxidation. Complete breakthrough of Ni within 100 pore volumes indicated no process of continuous uptake and was modeled as an equilibrium adsorption process. Nickel uptake in the presence of dissolved Mn was 67-100% reversible. Sediment extractions suggest that Ni uptake occurred through weak and strong adsorption. Continuous uptake of cobalt increased with sediment manganese oxide content, and Co uptake was up to 75% greater under biotic than abiotic conditions. Cobalt uptake was controlled by both existing and newly formed manganese oxides. Only a small amount of Co uptake was reversible (10-25%). XANES spectral analysis indicated that most Co(II) was oxidized to Co(III) and probably incorporated structurally into manganese oxides. Although manganese oxides were the primary phase controlling uptake and retention of Mn, Ni, and Co, the mechanisms varied among the metals.

Lipid Peroxidation and Antioxidant Status in Patients with Medullary Thyroid Carcinoma: A Case-Control Study

PubMed Central

Hosseini-Zijoud, Seyed-Mostafa; Ebadi, Seyed Alireza; Goodarzi, Mohammad Taghi; Hedayati, Mehdi; Abbasalipourkabir, Roghayeh; Mahjoob, Mohammad Parsa; Poorolajal, Jalal; Zicker, Fabio

2016-01-01

Introduction Oxidative stress or oxidant/antioxidant imbalance has a crucial role in the pathogenesis of some diseases like cancer. Medullary thyroid carcinoma (MTC) originates in the thyroid parafollicular cells and includes 3-4% of the malignant neoplasms that have an effect on this gland. The aetiology of MTC has not been clarified. However, oxidative stress may be one of the factors involved. Aim The aim of the current study was to evaluate the antioxidant enzyme activity of catalase (CAT), Glutathione (GSH), total antioxidant capacity (TAC) and the levels of the lipid peroxidation product malondialdehyde (MDA) in blood samples of MTC patients as compared to healthy controls. Materials and Methods A case-control study was designed enrolling patients with confirmed MTC diagnosis and age-and sex group matched healthy volunteers referred to the clinic of the Research Institute for Endocrine Sciences, Tehran, Iran from April 2013 to July 2015. Fasting blood samples were taken for study. Catalase, GSH, MDA and TAC levels were measured by colorimetry using commercial kits (ZellBio GmbH, Germany). Data were analysed using SPSS 17 software, comparing mean±SD through t-test and difference between proportions through chi-square. Results No statistical difference was observed in the demographic characteristic between cases and controls. The final MTC group included 40 males and 45 females with a mean age of 30±12.9 year, and the control group 40 males and 47 females, with a mean age of 31.2±12.3 year. Anthropometric parameters, dietary and thyroid hormones levels (T3, T4 and TSH) were similar. Serum TAC (p=0.015), GSH (p=0.029) and CAT (p<0.001) levels were found to be significantly lower in the MTC patients, while serum MDA levels were significantly higher in MTC patients than controls (p<0.001). Conclusion These preliminary findings suggest that oxidant/antioxidant imbalance may be associated with or possibly indicate an increased risk to medullary thyroid carcinoma. Further studies are needed to explore these findings. PMID:27042443

Control of manganese dioxide particles resulting from in situ chemical oxidation using permanganate.

PubMed

Crimi, Michelle; Ko, Saebom

2009-02-01

In situ chemical oxidation using permanganate is an approach to organic contaminant site remediation. Manganese dioxide particles are products of permanganate reactions. These particles have the potential to deposit in the subsurface and impact the flow-regime in/around permanganate injection, including the well screen, filter pack, and the surrounding subsurface formation. Control of these particles can allow for improved oxidant injection and transport and contact between the oxidant and contaminants of concern. The goals of this research were to determine if MnO(2) can be stabilized/controlled in an aqueous phase, and to determine the dependence of particle stabilization on groundwater characteristics. Bench-scale experiments were conducted to study the ability of four stabilization aids (sodium hexametaphosphate (HMP), Dowfax 8390, xanthan gum, and gum arabic) in maintaining particles suspended in solution under varied reaction conditions and time. Variations included particle and stabilization aid concentrations, ionic content, and pH. HMP demonstrated the most promising results, as compared to xanthan gum, gum arabic, and Dowfax 8390 based on results of spectrophotometric studies of particle behavior, particle filtration, and optical measurements of particle size and zeta potential. HMP inhibited particle settling, provided for greater particle stability, and resulted in particles of a smaller average size over the range of experimental conditions evaluated compared to results for systems that did not include HMP. Additionally, HMP did not react unfavorably with permanganate. These results indicate that the inclusion of HMP in a permanganate oxidation system improves conditions that may facilitate particle transport.

The COFU3 Study. Improvement in cognitive function, attention, mental performance with Pycnogenol® in healthy subjects (55-70) with high oxidative stress.

PubMed

Belcaro, G; Dugall, M; Ippolito, E; Hu, S; Saggino, A; Feragalli, B

2015-12-01

This 12-month product registry study evaluated the effects of supplementation with French pine bark extract (Pycnogenol(®)) on cognitive function, attention, and mental performance in healthy subjects with high oxidative stress. Healthy subjects (age range 55-70) were screened - within a cardiovascular screening program - for oxidative stress. Out of 150 subjects, high oxidative stress was present in 44; the use of the supplement Pycnogenol(®) was suggested (100 mg/day). These subjects decided to use Pycnogenol(®) and accepted to be evaluated by assessing cognitive functions. A group of subjects with comparable oxidative stress was followed as a reference. IQ Code (Informant Questionnaire on Cognitive Decline in the Elderly), daily tasks, cognitive function, oxidative stress and the short Blessed tests (SBT) were used (in defined scales) to evaluate cognitive functions (COFU). As for the IQ Code, at 12 months there was a significantlty total lower score in Pycnogenol(®) patients and also a lower value (P<0.05) for 14 out of 16 items in the questionnaire. Daily tasks: all items were improved (P<0.05) with supplementation in comparison with controls. The improvement was seen for all 12 items (P<0.05) with the supplement. Cognitive function values (visual scale line) indicated a significant improvement (P<0.05) in all elements present in the questionnaire with the 12-month supplementation (no significant variations in controls). Oxidative stress was comparable in both groups at inclusion. It was significantly decreased with Pycnogenol(®) (-28.07%; P<0.05) at 12 months; there was no decrease in controls. The short blessed test (SBT) value was significantly increased in controls (P<0.05); but significantly decreased in the Pycnogenol(®) group (P<0.05). Values for supplemented patients at 12 months were almost within the normal range (21 out or 38 were below the normal value of 4). Tolerability and compliance for Pycnogenol(®) were optimal with >97% of the doses of the supplement correctly used. No side effects were observed, recorded or described. Pycnogenol(®) supplementation for 12 months appears to improve cognitive function and oxidative stress in normal subjects between 55 and 70 years of age.

Investigation of Reaction Mechanism on the Lime-Free Roasting of Chromium-Containing Slag

NASA Astrophysics Data System (ADS)

Yu, Kai-ping; Zhang, Hong-ling; Chen, Bo; Xu, Hong-bin; Zhang, Yi

2015-12-01

The lime-free roasting process of trivalent chromium-containing slag was investigated. The effect of Fe and liquid phase on the conversion reaction of chromium was discussed. The oxidation of trivalent chromium depends greatly on the diffusion of Na+ and O2. Both the raw material Na2CO3 and the intermediate product NaFeO2 serve as the carriers of Na+. The Na+ diffusion is improved by the binary liquid phase of Na2CrO4-Na2CO3, whereas excess liquid phase results in a low conversion rate of chromium by hindering the diffusion of oxygen towards the reaction interface. With the increasing of liquid volume, the controlled step of chromium oxidation changes from Na+ diffusion to oxygen diffusion. The mechanism study showed that the volume of liquid phase increased while raising the reaction temperature or prolonging the reaction time. Based on the role of both liquid phase and Fe, the oxidation process of chromium was summarized as a three-stage model: the Na+ diffusion-controlled stage, the O2 diffusion-controlled stage, and the oxidation reaction halted stage.

Assessment of DNA damage in a group of professional dancers during a 10-month dancing season.

PubMed

Esteves, Filipa; Teixeira, Eduardo; Amorim, Tânia; Costa, Carla; Pereira, Cristiana; Fraga, Sónia; De Andrade, Vanessa Moraes; Teixeira, João Paulo; Costa, Solange

2017-01-01

Despite the numerous health benefits of physical activity, some studies reported that increased intensity and duration may induce oxidative stress in several cellular components including DNA. The aim of this study was to assess the level of basal DNA damage as well as oxidative DNA damage in a group of professional dancers before and after a 10-month dancing season. A group of individuals from general population was also assessed as a control. The alkaline version of the comet assay was the method selected to measure both basal DNA damage and oxidative stress, since this method quantifies both endpoints. In order to measure oxidative stress, the comet assay was coupled with a lesion-specific endonuclease (formamidopyrimidine glycosylase) to detect oxidized purines. The levels of oxidative DNA damage in dancers were significantly increased after the dancing season. Pre-season levels of oxidative DNA damage were lower in dancers than those obtained from the general population, suggesting an adaptation of antioxidant system in dancers. Results of the present biomonitoring study indicate the need for more effective measures to protect ballet dancers from potentially occupational health risks related to regular intensive physical exercise.

Impairment of mitochondrial β-oxidation in rats under cold-hypoxic environment

NASA Astrophysics Data System (ADS)

Dutta, Arkadeb; Vats, Praveen; Singh, Vijay K.; Sharma, Yogendra K.; Singh, Som N.; Singh, Shashi B.

2009-09-01

Mitochondrial ß-oxidation of fatty acid provides a major source of energy in mammals. High altitude (HA), characterized by hypobaric hypoxia and low ambient temperatures, causes alteration in metabolic homeostasis. Several studies have depicted that hypoxic exposure in small mammals causes hypothermia due to hypometabolic state. Moreover, cold exposure along with hypoxia reduces hypoxia tolerance in animals. The present study investigated the rate of β-oxidation and key enzymes, carnitine palmitoyl transferase-I (CPT-I) and hydroxyacyl CoA dehydrogenase (HAD), in rats exposed to cold-hypobaric hypoxic environment. Male Sprague Dawley rats (190-220 g) were randomly divided into eight groups ( n = 6 rats in each group): 1 day hypoxia (H1); 7 days hypoxia (H7); 1 day cold (C1); 7 days cold (C7); 1 day cold-hypoxia (CH1); 7 days cold-hypoxia (CH7) exposed; and unexposed control for 1 and 7 days (UC1 and UC7). After exposure, animals were anaesthetized with ketamine (50 mg/kg body weight) and xylazine (10 mg/kg body weight) intraperitonialy and sacrificed. Mitochondrial CPT-I, HAD, 14C-palmitate oxidation in gastrocnemius muscle and liver, and plasma leptin were measured. Mitochondrial CPT-I was significantly reduced in muscle and liver in CH1 and CH7 as compared to respective controls. HAD activity was significantly reduced in H1 and CH7, and in H1, H7, CH1, and CH7 as compared to unexposed controls in muscle and liver, respectively. A concomitant decrease in 14C-palmitate oxidation was found. Significant reduction in plasma leptin in hypoxia and cold-hypoxia suggested hypometabolic state. It can be concluded that ß-oxidation of fatty acids is reduced in rats exposed to cold-hypoxic environment due to the persisting hypometabolic state in cold-hypoxia exposure.

Effect of obesity reduction on preservation of heart function and attenuation of left ventricular remodeling, oxidative stress and inflammation in obese mice

PubMed Central

2012-01-01

Background Obesity is an important cardiovascular risk factor. This study tested the effect of obesity reduction on preserving left ventricular ejection fraction (LVEF) and attenuating inflammation, oxidative stress and LV remodeling in obese mice. Methods and results Eight-week-old C57BL/6 J mice (n=24) were equally divided into control (fed a control diet for 22 weeks), obesity (high-fat diet, 22 weeks), and obese reduction (OR) (high-fat diet, 14 weeks; then control diet, 8 weeks). Animals were sacrificed at post 22-week high-fat diet and the LV myocardium collected. Heart weight, body weight, abdominal-fat weight, total cholesterol level and fasting blood glucose were higher in obesity than in control and OR (all p<0.001). Inflammation measured by mRNA expressions of IL-6, MMP-9, PAI-1 and leptin and protein expression of NF-κB was higher, whereas anti-inflammation measured by mRNA expressions of adiponectin and INF-γ was lower in obesity than in control and OR (all p<0.003). Oxidative protein expressions of NOX-1, NOX-2 and oxidized protein were higher, whereas expression of anti-oxidant markers HO-1 and NQO-1 were lower (all p<0.01); and apoptosis measured by Bax and caspase 3 was higher, whereas anti-apoptotic Bcl-2 was lower in obesity as compared with control and OR (all p<0.001). The expressions of fibrotic markers phosphorylated Smad3 and TGF-β were higher, whereas expression of anti-fibrotic phosphorylated Smad1/5 and BMP-2 were lower (all p<0.02); and LVEF was lower, whereas the LV remodeling was higher in obesity than in control and OR (all p<0.001). Conclusion Impaired LVEF, enhanced LV remodeling, inflammation, fibrosis, oxidative stress and apoptosis were reversed by reduction in mouse obesity. PMID:22784636

Phototherapy causes DNA damage in peripheral mononuclear leukocytes in term infants.

PubMed

Aycicek, Ali; Kocyigit, Abdurrahim; Erel, Ozcan; Senturk, Hakan

2008-01-01

Our aim was to determine whether endogenous mononuclear leukocyte DNA strand is a target of phototherapy. The study included 65 term infants aged between 3-10 days that had been exposed to intensive (n = 23) or conventional (n = 23) phototherapy for at least 48 hours due to neonatal jaundice, and a control group (n = 19). DNA damage was assayed by single-cell alkaline gel electrophoresis (comet assay). Plasma total antioxidant capacity and total oxidant status levels were also measured, and correlation between DNA damage and oxidative stress was investigated. Mean values of DNA damage scores in both the intensive and conventional phototherapy groups were significantly higher than those in the control group (p < 0.001). Mean values and standard deviation were 32 (9), 28 (9), 21 (7) arbitrary unit, respectively. Total oxidant status levels in both the intensive and conventional phototherapy groups were significantly higher than those in the control group (p = 0.005). Mean (standard deviation) values were 18.1 (4.2), 16.9 (4.4), 13.5 (4.2) micromol H2O2 equivalent/L, respectively. Similarly, oxidative stress index levels in both the intensive and conventional phototherapy groups were significantly higher than those in the control group (p = 0.041). Plasma total antioxidant capacity and total bilirubin levels did not differ between the groups (p > 0.05). There were no significant correlations between DNA damage scores and bilirubin, total oxidant status and oxidative stress levels in either phototherapy group (p > 0.05). Both conventional phototherapy and intensive phototherapy cause endogenous mononuclear leukocyte DNA damage in jaundiced term infants.

Oxidation State Discrimination in the Atomic Layer Deposition of Vanadium Oxides

DOE PAGES

Weimer, Matthew S.; Kim, In Soo; Guo, Peijun; ...

2017-06-02

We describe the use of a vanadium 3+ precursor for atomic layer deposition (ALD) of thin films that span the common oxidation states of vanadium oxides. Self-limiting surface synthesis of V 2O 3, VO 2, and V 2O 5 are realized via four distinct reaction mechanisms accessed via judicious choice of oxygen ALD partners. In situ quartz crystal microbalance and quadrupole mass spectrometry were used to study the reaction mechanism of the vanadium precursor with O 3, H 2O 2, H 2O/O 2, and H 2O 2/H 2. A clear distinction between non-oxidative protic ligand exchange and metal oxidation ismore » demonstrated through sequential surface reactions with different non-metal precursors. This synergistic effect, provides greater control of the resultant metal species in the film, as well as reactive surface species during growth. In an extension of this approach, we introduce oxidation state control through reducing equivalents of H 2 gas. When H 2 is dosed after H 2O 2 during growth, amorphous films of VO 2 are deposited that are readily crystallized with a low temperature anneal. These VO 2 films show a temperature dependent Raman spectroscopy response in the expected range and consistent with the well-known phase-change behavior of VO 2.« less

Interrogation of bimetallic particle oxidation in three dimensions at the nanoscale

PubMed Central

Han, Lili; Meng, Qingping; Wang, Deli; Zhu, Yimei; Wang, Jie; Du, Xiwen; Stach, Eric A.; Xin, Huolin L.

2016-01-01

An understanding of bimetallic alloy oxidation is key to the design of hollow-structured binary oxides and the optimization of their catalytic performance. However, one roadblock encountered in studying these binary oxide systems is the difficulty in describing the heterogeneities that occur in both structure and chemistry as a function of reaction coordinate. This is due to the complexity of the three-dimensional mosaic patterns that occur in these heterogeneous binary systems. By combining real-time imaging and chemical-sensitive electron tomography, we show that it is possible to characterize these systems with simultaneous nanoscale and chemical detail. We find that there is oxidation-induced chemical segregation occurring on both external and internal surfaces. Additionally, there is another layer of complexity that occurs during the oxidation, namely that the morphology of the initial oxide surface can change the oxidation modality. This work characterizes the pathways that can control the morphology in binary oxide materials. PMID:27928998

OXIDATION SCREENING STUDIES FOR CCL ORGANIC CHEMICALS

EPA Science Inventory

The understanding of the oxidation reactions associated with the Agency's Contaminant Candidate List (CCL)chemicals is important from several perspectives. Chemicals are added to the CCL because of their potential to negatively impact human health. The removal/control of that che...

Heteroaggregation of cerium oxide nanoparticles and nanoparticles of pyrolyzed biomass

USDA-ARS?s Scientific Manuscript database

Heteroaggregation with indigenous particles is an important process controlling the mobility of engineered nanomaterials in the environment. We studied heteroaggregation of cerium oxide nanoparticles (n-CeO2), which are widely used commercially, with nanoparticles of pyrogenic carbonaceous material ...

Association of arginase I or nitric oxide-related factors with job strain in healthy workers

PubMed Central

Eguchi, Eri; Nagaoka, Kenjiro

2017-01-01

This study evaluated the associations between job strain and arginase I in 378 healthy Japanese factory workers by a cross-sectional study measuring nitric oxide (NO)-related parameters (arginase I, L-arginine, exhaled nitric oxide (FeNO), and NOx), clinical parameters, and job strain using a Japanese version of the Job Content Questionnaire by Karasek. Arginase I and FEV1% were negatively correlated with job strain and positively correlated with job control and social support. FeNO and hs-CRP were negatively correlated with job strain. Multiple regression analysis showed negative association of arginase I with job strain and positive association with job control and social support in females. It is concluded that serum levels of arginase I may be useful biomarkers for the diagnosis of job stress in healthy female workers, although many factors can be influencing the data. PMID:28403218

Oxidative DNA damage and oxidative stress in lead-exposed workers.

PubMed

Dobrakowski, M; Pawlas, N; Kasperczyk, A; Kozłowska, A; Olewińska, E; Machoń-Grecka, A; Kasperczyk, S

2017-07-01

There are many discrepancies among the results of studies on the genotoxicity of lead. The aim of the study was to explore lead-induced DNA damage, including oxidative damage, in relation to oxidative stress intensity parameters and the antioxidant defense system in human leukocytes. The study population consisted of 100 male workers exposed to lead. According to the blood lead (PbB) levels, they were divided into the following three subgroups: a group with PbB of 20-35 μg/dL (low exposure to lead (LE) group), a group with a PbB of 35-50 µg/dL (medium exposure to lead (ME) group), and a group with a PbB of >50 μg/dL (high exposure to lead (HE) group). The control group consisted of 42 healthy males environmentally exposed to lead (PbB < 10 μg/dL). A comet assay was used to measure the DNA damage in leukocytes. We measured the activity of superoxide dismutase (SOD), catalase, glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PD), and glutathione-S-transferase (GST) as well as the concentration of malondialdehyde (MDA), and the value of the total antioxidant capacity. The level of PbB was significantly higher in the examined subgroups than in the control group. The percentage of DNA in the tail was significantly higher in the LE, ME, and HE subgroups than in the control group by 10% ( p = 0.001), 15% ( p < 0.001), and 20% ( p < 0.001), respectively. The activity of GR was significantly lower in the LE and ME subgroups than in the control group by 25% ( p = 0.007) and 17% ( p = 0.028), respectively. The activity of G6PD was significantly lower in the ME subgroup by 25% ( p = 0.022), whereas the activity of GST was significantly higher in the HE subgroup by 101% ( p = 0.001) than in the control group. Similarly, the activity of SOD was significantly higher in the LE and ME subgroups by 48% ( p = 0.026) and 34% ( p = 0.002), respectively. The concentration of MDA was significantly higher in the LE, ME, and HE subgroups than in the control group by 43% ( p = 0.016), 57% ( p < 0.001), and 108% ( p < 0.001), respectively. Occupational lead exposure induces DNA damage, including oxidative damage, in human leukocytes. The increase in DNA damage was accompanied by an elevated intensity of oxidative stress.

Mitochondrial quality control: decommissioning power plants in neurodegenerative diseases.

PubMed

Mukherjee, Rukmini; Chakrabarti, Oishee

2013-01-01

The cell has an intricate quality control system to protect its mitochondria from oxidative stress. This surveillance system is multi-tiered and comprises molecules that are present inside the mitochondria, in the cytosol, and in other organelles like the nucleus and endoplasmic reticulum. These molecules cross talk with each other and protect the mitochondria from oxidative stress. Oxidative stress is a fundamental part of early disease pathogenesis of neurodegenerative diseases. These disorders also damage the cellular quality control machinery that protects the cell against oxidative stress. This exacerbates the oxidative damage and causes extensive neuronal cell death that is characteristic of neurodegeneration.

Effect of surface oxidation on emissivity properties of pure aluminum in the near infrared region

NASA Astrophysics Data System (ADS)

Zhang, Kaihua; Yu, Kun; Liu, Yufang; Zhao, Yuejin

2017-08-01

Emissivity is a basic thermo physical property of materials and determines the precision of radiation thermometry. The aim of this paper is to study the effect of surface oxidation on the infrared emissivity properties of pure aluminum. The emissivity data presented in this study covers the spectral range between 0.8 and 2.2 µm and temperatures from 473 to 873 K. The samples with different oxidation time were prepared under a controlled environment. The morphology and composition of the samples were characterized by metallographic microscope and XRD techniques before and after oxidation. The thickness of oxide film with different oxidation time was accurately measured by spectroscopic ellipsometer and a parabolic growth was found. In addition, the interference model of an oxidized metal substrate is established to explain the influence of the oxide film thickness on the emissivity. The thickness of oxide film when the interference effect occurs was calculated according to the interference model. The data shows that the maximum value measured was less than the thickness value at the first order constructive interference. Neither peaks nor valleys were observed in emissivity measurements with different oxidation time at 873 K, which could be related to the thin oxide film on sample surface.

Unique structure and regulation of the nematode detoxification gene regulator SKN-1: implications to understanding and controlling drug resistance

PubMed Central

Choe, Keith P.; Leung, Chi K.; Miyamoto, Michael M.

2012-01-01

Nematodes parasitize an alarming number of people and agricultural animals globally and cause debilitating morbidity and mortality. Anthelmintics have been the primary tools used to control parasitic nematodes for the past several decades, but drug resistance is becoming a major obstacle. Xenobiotic detoxification pathways defend against drugs and other foreign chemicals in diverse organisms, and evidence is accumulating that they play a role in mediating resistance to anthelmintics in nematodes. Related anti-oxidation pathways may also provide filarial parasites protection against host free radical-mediated immune responses. Upstream regulatory pathways have received almost no attention in nematode parasites despite their potential to co-regulate multiple detoxification and anti-oxidation genes. The NRF2 transcription factor mediates inducible detoxification and anti-oxidation defenses in mammals and recent studies have demonstrated that it promotes multidrug resistance in some human tumors. Recent studies in the free-living model nematode Caenorhabditis elegans have defined the homologous transcription factor SKN-1 as a master regulator of detoxification and anti-oxidation genes. Despite similar functions, SKN-1 and NRF2 have important differences in structure and regulatory pathways. Protein alignment and phylogenetic analyses indicate that these differences are shared among many nematodes making SKN-1 a candidate for specifically targeting nematode detoxification and anti-oxidation. PMID:22656429

Flux control exerted by overt carnitine palmitoyltransferase over palmitoyl-CoA oxidation and ketogenesis is lower in suckling than in adult rats.

PubMed Central

Krauss, S; Lascelles, C V; Zammit, V A; Quant, P A

1996-01-01

We examined the potential of overt carnitine palmitoyltransferase (CPT I) to control the hepatic catabolism of palmitoyl-CoA in suckling and adult rats, using a conceptually simplified model of fatty acid oxidation and ketogenesis. By applying top-down control analysis, we quantified the control exerted by CPT I over total carbon flux from palmitoyl-CoA to ketone bodies and carbon dioxide. Our results show that in both suckling and adult rat, CPT I exerts very significant control over the pathways under investigation. However, under the sets of conditions we studied, less control is exerted by CPT I over total carbon flux in mitochondria isolated from suckling rats than in those isolated from adult rats. Furthermore the flux control coefficient of CPT I changes with malonyl-CoA concentration and ATP turnover rate. PMID:8912677

Novel approach on the risk assessment of oxidized fats and oils for perspectives of food safety and quality. I. Oxidized fats and oils induces neurotoxicity relating pica behavior and hypoactivity.

PubMed

Gotoh, N; Watanabe, H; Osato, R; Inagaki, K; Iwasawa, A; Wada, S

2006-04-01

Food poisoning caused by deteriorated fat and oil in instant noodles was first reported in Japan approximately 40 years ago. In these cases, many people developed neurotoxic symptoms such as emesis and discomfort. The degree of oxidation of the fat and oil in the instant noodles that induced food poisoning was at least 100 meq/kg in peroxide value (PV). No general toxicity studies with animals, however, have examined the toxicity of fat and oil oxidized to that extent. In this study, pica behavior, a behavior characterized by eating a nonfood material such as kaolin and that relates to the degree of discomfort in animals, and alterations of locomotor activity of rats eating deteriorated fat and oil were measured. The groups fed fat and oil with at least 138.5 meq/kg PV consumed significantly more kaolin compared to the control group. Furthermore, rats that ate deteriorated fat and oil with at least 107.2 meq/kg PV had significantly decreased locomotor activity compared to control rats. These phenomena suggest that oxidized fat and oil with at least 100 meq/kg PV induce neurotoxicity. The toxicity of oxidized fat and oil has only been addressed using general toxicity tests, but the present results reveal the importance of evaluating toxicity by using other measures.

AIR POLLUTION CONTROL TECHNOLOGIES

EPA Science Inventory

This is a chapter for John Wiley & Son's Mechanical Engineers' Handbook, and covers issues involving air pollution control. Various technologies for controlling sulfur oxides is considered including fuel desulfurization. It also considers control of nitrogen oxides including post...

Remote sensing of nitric oxide emissions from planes, trains and automobiles

NASA Astrophysics Data System (ADS)

Popp, Peter John

Remote sensing has been proven as an effective method for measuring in-use mobile source emissions. This document describes the development of a remote sensor for mobile source nitric oxide, based on an instrument previously developed at the University of Denver for measuring carbon monoxide and hydrocarbon emissions. The new remote sensor makes use of a high-speed ultraviolet spectrometer to quantify nitric oxide by absorption spectroscopy at 226 nm in the ultraviolet region. The high-speed spectrometer is coupled to an existing FEAT remote sensor, for the simultaneous measurement of CO, CO2 and hydrocarbons by non-dispersive infrared absorption spectroscopy. The utility of the instrument was demonstrated in the measurement of nitric oxide emissions from automobiles, commercial aircraft, and railroad locomotives. The remote sensor was used to measure nitric oxide emissions from motor vehicles in Chicago in 1997 and 1998, as part of a five-year study to characterize motor vehicle emissions and deterioration in that city. Emissions data were collected for over 19,000 vehicles in 1997 and almost 23,000 vehicles in 1998. All of these records contained valid measurements for carbon monoxide and hydrocarbons, in addition to nitric oxide. In September of 1997, a study was conducted with the cooperation of British Airways and the British Airports Authority to demonstrate the capability of the remote sensor in measuring nitric oxide emissions from in-use commercial aircraft. In two days of sampling at London Heathrow Airport, a total of 122 measurements were made of 90 different aircraft, ranging in size from Gulfstream executive jets to Boeing 747-400s. The measured nitric oxide emission indices were not inconsistent with commercial aircraft emission indices published by the International Civil Aviation Organization. The utility of the remote sensor in measuring nitric oxide emissions from railroad locomotives was demonstrated in January of 1999, in a study conducted with the cooperation of the Burlington Northern Santa Fe Railway. Nitric oxide emissions measured from freight locomotives in a controlled test at a switchyard agreed with previously published values. Measurements of in-use locomotives hauling coal trains revealed higher NO emissions than those measured from similar locomotives in the controlled test.

Degradation of superconducting Nb/NbN films by atmospheric oxidation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henry, M. David; Wolfley, Steve; Young, Travis

2017-03-01

Niobium and niobium nitride thin films are transitioning from fundamental research toward wafer scale manufacturing with technology drivers that include superconducting circuits and electronics, optical single photon detectors, logic, and memory. Successful microfabrication requires precise control over the properties of sputtered superconducting films, including oxidation. Previous work has demonstrated the mechanism in oxidation of Nb and how film structure could have deleterious effects upon the superconducting properties. This study provides an examination of atmospheric oxidation of NbN films. By examination of the room temperature sheet resistance of NbN bulk oxidation was identified and confirmed by secondary ion mass spectrometry. Asmore » a result, Meissner magnetic measurements confirmed the bulk oxidation not observed with simple cryogenic resistivity measurements.« less

Observing BVOC Emissions, Oxidation, Deposition, and Interactions with Anthropogenic Pollutants to Form SOA in the Southeast United States

NASA Astrophysics Data System (ADS)

Goldstein, A. H.; Isaacman, G. A.; Misztal, P. K.; Yee, L.; Olson, K. F.; Moss, J.; Kreisberg, N. M.; Hering, S. V.; Park, J. H.; Kaser, L.; Seco, R.; Guenther, A. B.; Su, L.; Mak, J. E.; Holzinger, R.; Hu, W.; Campuzano Jost, P.; Palm, B. B.; Day, D. A.; Jimenez, J. L.; Koss, A.; De Gouw, J. A.

2014-12-01

Our overarching goals in the SOAS 2013 campaign were to 1) quantify biogenic VOC emission and VOC deposition to understand the processes controlling these bi-directional exchanges, 2) observe a broad suite of primary VOC and their oxidation products in the field and in controlled laboratory experiments, and 3) investigate their fate to understand how anthropogenic pollution alters oxidation pathways and secondary organic aerosol (SOA) formation. We pursued these goals through measurement of atmospheric organics ranging from very volatile (using in-situ GC-MS and proton transfer reaction time-of-flight MS, PTR-ToF-MS) to semi-volatile gas and particle phase compounds (using the Semi-Volatile Thermal desorption Aerosol Gas chromatograph, SV-TAG). Measured concentrations and fluxes of VOCs at the top of the SEARCH tower were coordinated with concentration gradients and fluxes at the AABC flux tower site, and vertical profiles using the Long-EZ aircraft to provide equivalent observations across sites. These results are informed through measurements using the same instrument during the FIXIT controlled laboratory oxidation study at CalTech that investigated oxidation pathways of BVOC with varying levels of anthropogenic pollutants. Measurements by SV-TAG of particle-phase and total gas-plus-particle-phase compounds at the SEARCH tower provide hourly quantification of semi-volatile compounds, including the oxidation products of measured VOCs. Derivatization of hydroxyl groups prior to GC analysis allows analysis of highly oxidized chemicals, including most known tracers. Methyl tetrols, an oxidation product of isoprene, had a significant day-time gas-phase component, and their abundance was strongly correlated with particle-phase sulfate, indicative of anthropogenic influence on the formation or partitioning processes. Similar observations of pinic acid (monterpene oxidation product) and many other BVOC oxidation products were made in both the gas and particle phases. Through measurements of specific chemical tracers across a wide range of volatilities, we explore the chemical lifecycle of BVOCs to understand anthropogenic-biogenic interactions in aerosol formation.

40 CFR 52.578 - Control Strategy: Sulfur oxides and particulate matter.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control Strategy: Sulfur oxides and... Strategy: Sulfur oxides and particulate matter. Link to an amendment published at 76 FR 31859, June 2, 2011... user, the added text is set forth as follows: § 52.578 Control Strategy: Sulfur oxides and particulate...

An anthocyanin/polyphenolic-rich fruit juice reduces oxidative DNA damage and increases glutathione level in healthy probands.

PubMed

Weisel, Tamara; Baum, Matthias; Eisenbrand, Gerhard; Dietrich, Helmut; Will, Frank; Stockis, Jean-Pierre; Kulling, Sabine; Rüfer, Corinna; Johannes, Christian; Janzowski, Christine

2006-04-01

Oxidative cell damage is involved in the pathogenesis of atherosclerosis, cancer, diabetes and other diseases. Uptake of fruit juice with especially high content of antioxidant flavonoids/polyphenols, might reduce oxidative cell damage. Therefore, an intervention study was performed with a red mixed berry juice [trolox equivalent antioxidative capacity (TEAC): 19.1 mmol/L trolox] and a corresponding polyphenol-depleted juice (polyphenols largely removed, TEAC 2.4 mmol/L trolox), serving as control. After a 3-week run-in period, 18 male probands daily consumed 700 mL juice, and 9 consumed control juice, in a 4-week intervention, followed by a 3-week wash-out. Samples were collected weekly to analyze DNA damage (comet assay), lipid peroxidation (plasma malondialdehyde: HPLC/fluorescence; urinary isoprostanes: GC-MS), blood glutathione (photometrically), DNA-binding activity of nuclear factor-kappaB (ELISA) and plasma carotenoid/alpha-tocopherol levels (HPLC-DAD). During intervention with the fruit juice, a decrease of oxidative DNA damage (p<5x10(-4)) and an increase of reduced glutathione (p<5x10(-4)) and of glutathione status (p<0.05) were observed, which returned to the run-in levels in the subsequent wash-out phase. The other biomarkers were not significantly modulated by the juice supplement. Intervention with the control juice did not result in reduction of oxidative damage. In conclusion, the fruit juice clearly reduces oxidative cell damage in healthy probands.

Prospect of nitric oxide as a new fumigant for postharvest pest control

USDA-ARS?s Scientific Manuscript database

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. In laboratory tests, complete control was achieved against all insect and mite species tested to date with 0.2% to 5% NO fumigations in 2 h to 48 h at 2 to 25°C depending on species and life stages. Nitric oxide reacts ...

Effects of Cinnamon, Cardamom, Saffron, and Ginger Consumption on Markers of Glycemic Control, Lipid Profile, Oxidative Stress, and Inflammation in Type 2 Diabetes Patients.

PubMed

Azimi, Paria; Ghiasvand, Reza; Feizi, Awat; Hariri, Mitra; Abbasi, Behnoud

2014-01-01

Type 2 diabetes (T2D) may be caused by elevated oxidative stress, inflammation, and hyperglycemia. The phytochemicals in several herbal medicines are reported to effectively improve diabetes and to ameliorate diabetic complications. The aim of the present study was to determine the effects of cinnamon, cardamom, saffron, and ginger as supplementary remedies in T2D. This randomized controlled, clinical trial included 204 T2D patients. The participants were randomly assigned to four intervention groups receiving 3 glasses of black tea and either 3 g cardamom, or cinnamon, or ginger, or 1 g saffron and one control group which consumed only 3 tea glasses without any herbal medicine for 8 weeks. Markers of inflammation, oxidative stress, fasting blood sugar, lipid profile, and anthropometric measures were evaluated at baseline and after 8 weeks of intervention. After 8 weeks of intervention, cinnamon, cardamom, ginger, and saffron consumption had significant effects on total cholesterol, LDL, and HDL levels (p < 0.05) compared with controls. However, the herbal products did not have significant effects on measures of glycemic control, anthropometry, inflammation, and oxidative stress. In within-group comparisons only, cinnamon intake significantly decreased fasting blood sugar (FBS). The herbal remedies examined had significantly beneficial effects on cholesterol, but not on measures of glycemic control, oxidative stress, and inflammation. Based on the contradictory results reported in the literature, the effects of herbal medicine in diabetic patients should undergo further detailed investigation.

Induction of NEIL1 and NEIL2 DNA glycosylases in aniline-induced splenic toxicity

PubMed Central

Ma, Huaxian; Wang, Jianling; Abdel-Rahman, Sherif Z.; Hazra, Tapas K.; Boor, Paul J.; Khan, M. Firoze

2011-01-01

The mechanisms by which aniline exposure elicits splenotoxic response, especially the tumorigenic response, are not well-understood. Earlier, we have shown that aniline-induced oxidative stress is associated with increased oxidative DNA damage in rat spleen. The base excision repair (BER) pathway is the major mechanism for the repair of oxidative DNA base lesions, and we have shown an up-regulation of 8-oxoguanine glycosylase 1 (OGG1), a specific DNA glycosylase involved in the removal of 8-hydroxy-2′-deoxyguanosine (8-OHdG) adducts, following aniline exposure. Nei-like DNA glycosylases (NEIL1/2) belong to a family of BER proteins that are distinct from other DNA glycosylases, including OGG1. However, contribution of NEIL1/2 in the repair of aniline-induced oxidative DNA damage in the spleen is not known. This study was, therefore, focused on evaluating if NEILs also contribute to the repair of oxidative DNA lesions in the spleen following aniline exposure. To achieve that, male SD rats were subchronically exposed to aniline (0.5 mmol/kg/day via drinking water for 30 days), while controls received drinking water only. The BER activity of NEIL1/2 was assayed using a bubble structure substrate containing 5-OHU (preferred substrates for NEIL1 and NEIL2) and by quantitating the cleavage products. Aniline treatment led to a 1.25-fold increase in the NEIL1/2-associated BER activity in the nuclear extracts of spleen compared to the controls. Real-time PCR analysis for NEIL1 and NEIL2 mRNA expression in the spleen revealed 2.7- and 3.9-fold increases, respectively, in aniline-treated rats compared to controls. Likewise, Western blot analysis showed that protein expression of NEIL1 and NEIL2 in the nuclear extract of spleens from aniline-treated rats was 2.0- and 3.8-fold higher than controls, respectively. Aniline treatment also led to stronger immunoreactivity for NEIL1 and NEIL2 in the spleens, confined to the red pulp areas. These studies, thus, show that aniline-induced oxidative stress is associated with an induction of NEIL1/2. The increased NIELs-mediated BER activity is another indication of aniline-induced oxidative damage in the spleen and could constitute another important mechanism of removal of oxidative DNA lesions, especially in transcribed DNA following aniline insult. PMID:21145906

Reduced graphene oxide-ZnO composites based gas sensors: A review

NASA Astrophysics Data System (ADS)

Thakare, N. B.; Raghuwanshi, F. C.; Kalyamwar, V. S.; Tamgadge, Y. S.

2018-05-01

The need to monitor and control life threatening gases has led to research and development of a wide variety of sensors using different materials and technologies. Recently rGO (reduced graphene oxide)-MOS (Metal Oxide Semiconductor) architectures have been studied for efficient and cost effective gas sensors that will operate at low temperature. In this review paper, we review latest findings and progress in rGO-ZnO composites as sensors to detect volatile and toxic gases.

Stable White Coatings

NASA Technical Reports Server (NTRS)

Zerlaut, Gene A.; Gilligan, J. E.; Harada, Y.

1965-01-01

In a previous research program for the Jet Propulsion- Laboratory, extensive studies led to the development and specifications of three zinc oxide-pigmented thermal-control coatings. The principal objectives of this program are: improvement of the three paints (as engineering materials), determination of the validity of our accelerated space-simulation testing, and continuation of the zinc oxide photolysis studies begun in the preceding program. Specific tasks that are discussed include: improvement of potassium silicate coatings as engineering materials and elucidation of their storage and handling problems; improvement of methyl silicone coatings as engineering materials; studies of zinc oxide photolysis to establish reasons for the observed stability of zinc oxide; and determination of space-simulation parameters such as long-term stability (to 8000 ESH), effect of coating surface temperature on the rate of degradation, and validity of accelerated testing (by reciprocity and wavelength dependency studies).

Obesity induced alterations in redox homeostasis and oxidative stress are present from an early age

PubMed Central

Lechuga-Sancho, Alfonso M.; Gallego-Andujar, David; Ruiz-Ocaña, Pablo; Visiedo, Francisco M.; Saez-Benito, Ana; Schwarz, Mónica; Segundo, Carmen

2018-01-01

Objectives Oxidative stress and inflammation have been postulated as underlying mechanisms for the development of obesity-related insulin resistance. This association however, remains elusive especially in childhood. We sought to investigate this relation by measuring oxidative stress and antioxidant response biomarkers, before and during an oral glucose tolerance test (OGTT), in different biological samples from obese children. Subjects 24 children were recruited for the study, (18 obese and 6 controls). After OGTT, the obese group was subdivided in two, according to whether or not carbohydrate metabolic impairment (Ob.IR+, Ob.IR-; respectively) was found. Different biomarkers were analyzed after fasting (T = 0) and during an OGTT (T = 60 and 120 min). Lipoperoxides were measured in plasma, erythrocytes, and urine; while advanced glycation end products were determined in plasma, and redox status (GSH/GSSG ratio) in erythrocytes. Results We found marked differences in the characterization of the oxidative status in urine and erythrocytes, and in the dynamics of the antioxidant response during OGTT. Specifically, Ob.IR+ children show increased oxidative stress, deficient antioxidant response and a significant imbalance in redox status, in comparison to controls and Ob.IR- children. Conclusion Obese children with insulin resistance show increased levels of oxidative stress biomarkers, and a stunted antioxidant response to an OGTT leading to increased oxidative stress after a single glucose load, as detected in erythrocytes, but not in plasma. We propose erythrocytes as sensors of early and acute changes in oxidative stress associated with insulin resistance in childhood obesity. This is a pilot study, performed with a limited sample size, so data should be interpreted with caution until reproduced. PMID:29370267

Growth and characterization of single phase Cu{sub 2}O by thermal oxidation of thin copper films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choudhary, Sumita; Sarma, J. V. N.; Gangopadhyay, Subhashis, E-mail: subhagan@yahoo.com

2016-04-13

We report a simple and efficient technique to form high quality single phase cuprous oxide films on glass substrate using thermal evaporation of thin copper films followed by controlled thermal oxidation in air ambient. Crystallographic analysis and oxide phase determination, as well as grain size distribution have been studied using X-ray diffraction (XRD) method, while scanning electron microscopy (SEM) has been utilized to investigate the surface morphology of the as grown oxide films. The formation of various copper oxide phases is found to be highly sensitive to the oxidation temperature and a crystalline, single phase cuprous oxide film can bemore » achieved for oxidation temperatures between 250°C to 320°C. Cu{sub 2}O film surface appeared in a faceted morphology in SEM imaging and a direct band gap of about 2.1 eV has been observed in UV-visible spectroscopy. X-ray photoelectron spectroscopy (XPS) confirmed a single oxide phase formation. Finally, a growth mechanism of the oxide film has also been discussed.« less

Fluorescent oxidation products and risk of coronary heart disease: a prospective study in women.

PubMed

Jensen, Majken K; Wang, Yushan; Rimm, Eric B; Townsend, Mary K; Willett, Walter; Wu, Tianying

2013-10-08

Oxidative stress is implicated in the etiology of coronary heart disease (CHD). New measures to capture oxidative stress are warranted. Fluorescent oxidation products (FlOPs) can be measured in plasma and have been shown to reflect levels of oxidative stress and to predict risk of CHD in men over 6 years of follow-up. The objective of this study is to determine whether measures of FlOPs are associated with risk of CHD in women over an extended follow-up period. We measured FlOP by spectrofluorometer in a nested case-control study within the Nurses' Health Study, with baseline blood collection in 1990 and follow-up of 397 incident CHD cases through 2004 matched 1:2 with controls. Level of FlOPs was independently associated with CHD. The relative risk across extreme quintiles was 1.64 (95% confidence interval [CI], 1.06 to 2.53) when adjusted for lifestyle factors, lipids and C-reactive protein (P trend across quintiles = 0.01). A slightly stronger association was observed when analyses were restricted to women fasting > 8 hours at blood draw (RR, 1.91; 95% CI, 1.16 to 3.15). In exploratory time to event analyses, high levels of FlOPs measured ≥ 5 years before the CHD event, but not closer to the CHD event, were associated with the risk of CHD. Higher levels of FlOPs were associated with the risk of CHD in women. The association appeared strongest for long-term prediction of CHD events.

Antioxidative effects of sulfurous mineral water: protection against lipid and protein oxidation.

PubMed

Benedetti, S; Benvenuti, F; Nappi, G; Fortunati, N A; Marino, L; Aureli, T; De Luca, S; Pagliarani, S; Canestrari, F

2009-01-01

To investigate the antioxidative properties of sulfurous drinking water after a standard hydropinic treatment (500 ml day(-1) for 2 weeks). Forty apparently healthy adults, 18 men and 22 women, age 41-55 years old. The antioxidant profile and the oxidative condition were evaluated in healthy subjects supplemented for 2 weeks with (study group) or without (controls) sulfurous mineral water both before (T0) and after (T1) treatment. At T1, a significant decrease (P<0.05) in both lipid and protein oxidation products, namely malondialdehyde, carbonyls and AOPP, was found in plasma samples from subjects drinking sulfurous water with respect to controls. Concomitantly, a significant increment (P<0.05) of the total antioxidant capacity of plasma as well as of total plasmatic thiol levels was evidenced. Tocopherols, carotenoids and retinol remained almost unchanged before and after treatment in both groups. The improved body redox status in healthy volunteers undergoing a cycle of hydropinic therapy suggests major benefits from sulfurous water consumption in reducing biomolecule oxidation, possibly furnishing valid protection against oxidative damage commonly associated with aging and age-related degenerative diseases.

40 CFR 52.2780 - Control strategy for sulfur oxides.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy for sulfur oxides. 52... strategy for sulfur oxides. (a) The requirements of subpart G of this chapter are not met since there has... maintenance of the national ambient air quality standards for sulfur oxides on the island of St. Croix. (b...

40 CFR 52.2780 - Control strategy for sulfur oxides.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 5 2014-07-01 2014-07-01 false Control strategy for sulfur oxides. 52... strategy for sulfur oxides. (a) The requirements of subpart G of this chapter are not met since there has... maintenance of the national ambient air quality standards for sulfur oxides on the island of St. Croix. (b...

40 CFR 52.2780 - Control strategy for sulfur oxides.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 5 2013-07-01 2013-07-01 false Control strategy for sulfur oxides. 52... strategy for sulfur oxides. (a) The requirements of subpart G of this chapter are not met since there has... maintenance of the national ambient air quality standards for sulfur oxides on the island of St. Croix. (b...

40 CFR 52.2780 - Control strategy for sulfur oxides.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Control strategy for sulfur oxides. 52... strategy for sulfur oxides. (a) The requirements of subpart G of this chapter are not met since there has... maintenance of the national ambient air quality standards for sulfur oxides on the island of St. Croix. (b...

Interim glycol flowsheet reduction/oxidation (redox) model for the Defense Waste Processing Facility (DWPF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C. M.; Williams, M. S.; Zamecnik, J. R.

Control of the REDuction/OXidation (REDOX) state of glasses containing high concentrations of transition metals, such as High Level Waste (HLW) glasses, is critical in order to eliminate processing difficulties caused by overly reduced or overly oxidized melts. Operation of a HLW melter at Fe +2/ΣFe ratios of between 0.09 and 0.33, a range which is not overly oxidizing or overly reducing, helps retain radionuclides in the melt, i.e. long-lived radioactive 99Tc species in the less volatile reduced Tc 4+ state, 104Ru in the melt as reduced Ru +4 state as insoluble RuO 2, and hazardous volatile Cr 6+ in themore » less soluble and less volatile Cr +3 state in the glass. The melter REDOX control balances the oxidants and reductants from the feed and from processing additives such as antifoam. Currently, the Defense Waste Processing Facility (DWPF) is running a formic acid-nitric acid (FN) flowsheet where formic acid is the main reductant and nitric acid is the main oxidant. During decomposition formate and formic acid releases H 2 gas which requires close control of the melter vapor space flammability. A switch to a nitric acid-glycolic acid (GN) flowsheet is desired as the glycolic acid flowsheet releases considerably less H 2 gas upon decomposition. This would greatly simplify DWPF processing. Development of an EE term for glycolic acid in the GN flowsheet is documented in this study.« less

Growth control of the oxidation state in vanadium oxide thin films

DOE PAGES

Lee, Shinbuhm; Meyer, Tricia L.; Park, Sungkyun; ...

2014-12-05

Precise control of the chemical valence or oxidation state of vanadium in vanadium oxide thin films is highly desirable for not only fundamental research, but also technological applications that utilize the subtle change in the physical properties originating from the metalinsulator transition (MIT) near room temperature. However, due to the multivalent nature of vanadium and the lack of a good understanding on growth control of the oxidation state, stabilization of phase pure vanadium oxides with a single oxidation state is extremely challenging. Here, we systematically varied the growth conditions to clearly map out the growth window for preparing phase puremore » epitaxial vanadium oxides by pulsed laser deposition for providing a guideline to grow high quality thin films with well-defined oxidation states of V₂⁺²O₃, V⁺⁴O₂, and V₂⁺⁵O₅. A well pronounced MIT was only observed in VO₂ films grown in a very narrow range of oxygen partial pressure P(O₂). The films grown either in lower (< 10 mTorr) or higher P(O₂) (> 25 mTorr) result in V₂O₃ and V₂O₅ phases, respectively, thereby suppressing the MIT for both cases. We have also found that the resistivity ratio before and after the MIT of VO₂ thin films can be further enhanced by one order of magnitude when the films are further oxidized by post-annealing at a well-controlled oxidizing ambient. This result indicates that stabilizing vanadium into a single valence state has to compromise with insufficient oxidation of an as grown thin film and, thereby, a subsequent oxidation is required for an 3 improved MIT behavior.« less

Growth control of the oxidation state in vanadium oxide thin films

NASA Astrophysics Data System (ADS)

Lee, Shinbuhm; Meyer, Tricia L.; Park, Sungkyun; Egami, Takeshi; Lee, Ho Nyung

2014-12-01

Precise control of the chemical valence or oxidation state of vanadium in vanadium oxide thin films is highly desirable for not only fundamental research but also technological applications that utilize the subtle change in the physical properties originating from the metal-insulator transition (MIT) near room temperature. However, due to the multivalent nature of vanadium and the lack of a good understanding on growth control of the oxidation state, stabilization of phase pure vanadium oxides with a single oxidation state is extremely challenging. Here, we systematically varied the growth conditions to clearly map out the growth window for preparing phase pure epitaxial vanadium oxides by pulsed laser deposition for providing a guideline to grow high quality thin films with well-defined oxidation states of V2 + 3 O 3 , V + 4 O 2 , and V2 + 5 O 5 . A well pronounced MIT was only observed in VO2 films grown in a very narrow range of oxygen partial pressure P(O2). The films grown either in lower (<10 mTorr) or higher P(O2) (>25 mTorr) result in V2O3 and V2O5 phases, respectively, thereby suppressing the MIT for both cases. We have also found that the resistivity ratio before and after the MIT of VO2 thin films can be further enhanced by one order of magnitude when the films are further oxidized by post-annealing at a well-controlled oxidizing ambient. This result indicates that stabilizing vanadium into a single valence state has to compromise with insufficient oxidation of an as grown thin film and, thereby, a subsequent oxidation is required for an improved MIT behavior.

Growth control of the oxidation state in vanadium oxide thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Shinbuhm; Meyer, Tricia L.; Lee, Ho Nyung, E-mail: hnlee@ornl.gov

2014-12-01

Precise control of the chemical valence or oxidation state of vanadium in vanadium oxide thin films is highly desirable for not only fundamental research but also technological applications that utilize the subtle change in the physical properties originating from the metal-insulator transition (MIT) near room temperature. However, due to the multivalent nature of vanadium and the lack of a good understanding on growth control of the oxidation state, stabilization of phase pure vanadium oxides with a single oxidation state is extremely challenging. Here, we systematically varied the growth conditions to clearly map out the growth window for preparing phase puremore » epitaxial vanadium oxides by pulsed laser deposition for providing a guideline to grow high quality thin films with well-defined oxidation states of V{sub 2}{sup +3}O{sub 3}, V{sup +4}O{sub 2}, and V{sub 2}{sup +5}O{sub 5}. A well pronounced MIT was only observed in VO{sub 2} films grown in a very narrow range of oxygen partial pressure P(O{sub 2}). The films grown either in lower (<10 mTorr) or higher P(O{sub 2}) (>25 mTorr) result in V{sub 2}O{sub 3} and V{sub 2}O{sub 5} phases, respectively, thereby suppressing the MIT for both cases. We have also found that the resistivity ratio before and after the MIT of VO{sub 2} thin films can be further enhanced by one order of magnitude when the films are further oxidized by post-annealing at a well-controlled oxidizing ambient. This result indicates that stabilizing vanadium into a single valence state has to compromise with insufficient oxidation of an as grown thin film and, thereby, a subsequent oxidation is required for an improved MIT behavior.« less

Melatonin and vitamin C attenuates alcohol-induced oxidative stress in aorta.

PubMed

Sönmez, Mehmet Fatih; Narin, Figen; Balcioğlu, Esra

2009-12-01

Epidemiological studies have shown that low to moderate doses of alcohol consumption are beneficial to cardiac health. However, chronic high doses of alcohol ingestion cause cardiovascular complications. The aim of this study was to investigate both the effects of melatonin and vitamin C and expression of endothelial nitric oxide synthase in aorta of chronic alcoholic rats. Twenty-four adult male Wistar rats weighing 200-250 g were used in the study. Rats were divided into four equal groups. Group I (control): rats were not fed on alcohol; Group II: rats were fed on alcohol; Group III: rats were fed on alcohol and 40 mg/kg vitamin C were injected intraperitoneally and Group IV: rats were fed on alcohol and 4 mg/kg melatonin were injected intraperitoneally. At the end of the experiment, rats were killed and aorta tissues were removed. Some parts of the aorta tissues were used for biochemical analyses and the other parts were used at histological procedures. In the control group, endothelial nitric oxide synthase immunoreactivity was (++) in smooth muscle cells and endothelial cells. Expression of endothelial nitric oxide synthase in the alcohol group was stronger than control group. Chronic ethanol ingestion significantly increased (p < 0.05); and melatonin significantly decreased both the plasma and tissue malondialdehyde levels. The superoxide dismutase levels and catalase activity did not change significantly in the Vitamin C and melatonin groups (p > 0.05) compared to the control and alcohol groups. The present results indicate that chronic alcohol consumption increase lipid peroxidation and cause endothelial nitric oxide synthase expression in the aorta. However, melatonin and vitamin C administration provide partial protection against alcohol-induced damage.

Oxidation Microstructure Studies of Reinforced Carbon/Carbon

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.; Curry, Donald M.

2006-01-01

Laboratory oxidation studies of reinforced carbon/carbon (RCC) are discussed with particular emphasis on the resulting microstructures. This study involves laboratory furnace (500-1500 C deg) and arc-jet exposures (1538 C deg) on various forms of RCC. RCC without oxidation protection oxidized at 800 and 1100 C deg exhibits pointed and reduced diameter fibers, due to preferential attack along the fiber edges. RCC with a SiC conversion coating exhibits limited attack of the carbon substrate at 500, 700 and 1500 C deg. However samples oxidized at 900, 1100, and 1300 C deg show small oxidation cavities at the SiC/carbon interface below through-thickness cracks in the SiC coating. These cavities have rough edges with denuded fibers and can be easily distinguished from cavities created in processing. Arc-jet tests at 1538 C deg show limited oxidation attack when the SiC coating and glass sealants are intact. When the SiC/sealant protection system is damaged, attack is extensive and proceeds through matrix cracks, creating denuded fibers on the edges of the cracks. Even at 1538 C deg, where diffusion control dominates, attack is non-uniform with fiber edges oxidizing in preference to the bulk fiber and matrix.

The level of serum lipids, vitamin E and low density lipoprotein oxidation in Wilson's disease patients.

PubMed

Rodo, M; Czonkowska, A; Pulawska, M; Swiderska, M; Tarnacka, B; Wehr, H

2000-09-01

The aim of this study was to estimate the level of lipids and of the main serum antioxidant, alpha-tocopherol (vitamin E), and to evaluate the susceptibility of low density lipoprotein (LDL) to oxidation in Wilson's disease patients. It was assumed that enhanced LDL peroxidation caused by high copper levels could contribute to the injury of liver and other tissues. The group investigated comprised 45 individuals with Wilson's disease treated with penicillamine or zinc salts and a control group of 36 healthy individuals. Lipids were determined by enzymatic methods, alpha-tocopherol by high performance liquid chromatography, the susceptibility of LDL to oxidation in vitro by absorption changes at 234 nm during 5 h and end-products of LDL lipid oxidation as thiobarbituric acid reacting substances. In Wilson's disease patients total cholesterol, LDL cholesterol and alpha-tocopherol levels were significantly lower compared with the control group. No difference in LDL oxidation in vitro between the patients and the controls was stated. enhanced susceptibility of isolated LDL for lipid peroxidation in vitro was not observed in Wilson's disease patients. One cannot exclude, however, that because of low alpha-tocopherol level lipid peroxidation in the tissues can play a role in the pathogenesis of tissue injury in this disease.

The controlled growth of perovskite thin films: Opportunities, challenges, and synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schlom, D.G.; Theis, C.D.; Hawley, M.E.

1997-10-01

The broad spectrum of electronic and optical properties exhibited by perovskites offers tremendous opportunities for microelectronic devices, especially when a combination of properties in a single device is desired. Molecular beam epitaxy (MBE) has achieved unparalleled control in the integration of semiconductors at the monolayer-level; its use for the integration of perovskites with similar nanoscale customization appears promising. Composition control and oxidation are often significant challenges to the growth of perovskites by MBE, but we show that these can be met through the use of purified ozone as an oxidant and real-time atomic absorption composition control. The opportunities, challenges, andmore » synthesis of oxide heterostructures by reactive MBE are described, with examples taken from the growth of oxide superconductors and oxide ferroelectrics.« less

Cardiovascular risk in systemic lupus erythematosus--evidence of increased oxidative stress and dyslipidaemia.

PubMed

Nuttall, S L; Heaton, S; Piper, M K; Martin, U; Gordon, C

2003-06-01

Systemic lupus erythematosus (SLE) is associated with severe and premature cardiovascular disease, which is not explained by traditional risk factors alone. This study aimed to investigate markers of oxidative stress, lipid metabolism and inflammation as potential cardiovascular risk factors in women with SLE. Venous blood samples were taken from 53 female Caucasian patients with SLE and from healthy age- and sex-matched controls. Samples were analysed for markers of oxidative stress, lipid metabolism [including low-density lipoprotein (LDL) subfraction profile] and C-reactive protein (CRP). Female SLE patients had an atherogenic lipid profile characterized by raised total cholesterol and triglycerides, and the presence of small, dense LDL subfractions compared with healthy controls. These changes were associated with increased oxidative damage and a moderately raised CRP. The results provide evidence for free radical and inflammatory activity in SLE and suggest potential targets to reduce the risk of cardiovascular disease in these patients.

Structural evolution of epitaxial SrCoO x films near topotactic phase transition

DOE PAGES

Jeen, Hyoung Jeen; Lee, Ho Nyung

2015-12-18

Control of oxygen stoichiometry in complex oxides via topotactic phase transition is an interesting avenue to not only modifying the physical properties, but utilizing in many energy technologies, such as energy storage and catalysts. However, detailed structural evolution in the close proximity of the topotactic phase transition in multivalent oxides has not been much studied. In this work, we used strontium cobaltites (SrCoO x) epitaxially grown by pulsed laser epitaxy (PLE) as a model system to study the oxidation-driven evolution of the structure, electronic, and magnetic properties. We grew coherently strained SrCoO 2.5thin films and performed post-annealing at various temperaturesmore » for topotactic conversion into the perovskite phase (SrCoO 3-δ). We clearly observed significant changes in electronic transport, magnetism, and microstructure near the critical temperature for the topotactic transformation from the brownmillerite to the perovskite phase. Furthermore, the overall crystallinity was well maintained without much structural degradation, indicating that topotactic phase control can be a useful tool to control the physical properties repeatedly via redox reactions.« less

Impact of diabetes on gingival wound healing via oxidative stress

PubMed Central

Kido, Daisuke; Mizutani, Koji; Takeda, Kohei; Mikami, Risako; Matsuura, Takanori; Iwasaki, Kengo; Izumi, Yuichi

2017-01-01

The aim of this study is to investigate the mechanisms linking high glucose to gingival wound healing. Bilateral wounds were created in the palatal gingiva adjacent to maxillary molars of control rats and rats with streptozotocin-induced diabetes. After evaluating postsurgical wound closure by digital imaging, the maxillae including wounds were resected for histological examinations. mRNA expressions of angiogenesis, inflammation, and oxidative stress markers in the surgical sites were quantified by real-time polymerase chain reaction. Primary fibroblast culture from the gingiva of both rats was performed in high glucose and normal medium. In vitro wound healing and cell proliferation assays were performed. Oxidative stress marker mRNA expressions and reactive oxygen species production were measured. Insulin resistance was evaluated via PI3K/Akt and MAPK/Erk signaling following insulin stimulation using Western blotting. To clarify oxidative stress involvement in high glucose culture and cells of diabetic rats, cells underwent N-acetyl-L-cysteine treatment; subsequent Akt activity was measured. Wound healing in diabetic rats was significantly delayed compared with that in control rats. Nox1, Nox2, Nox4, p-47, and tumor necrosis factor-α mRNA levels were significantly higher at baseline in diabetic rats than in control rats. In vitro study showed that cell proliferation and migration significantly decreased in diabetic and high glucose culture groups compared with control groups. Nox1, Nox2, Nox4, and p47 expressions and reactive oxygen species production were significantly higher in diabetic and high glucose culture groups than in control groups. Akt phosphorylation decreased in the high glucose groups compared with the control groups. Erk1/2 phosphorylation increased in the high glucose groups, with or without insulin treatment, compared with the control groups. Impaired Akt phosphorylation partially normalized after antioxidant N-acetyl-L-cysteine treatment. Thus, delayed gingival wound healing in diabetic rats occurred because of impaired fibroblast proliferation and migration. Fibroblast dysfunction may occur owing to high glucose-induced insulin resistance via oxidative stress. PMID:29267310

Impact of diabetes on gingival wound healing via oxidative stress.

PubMed

Kido, Daisuke; Mizutani, Koji; Takeda, Kohei; Mikami, Risako; Matsuura, Takanori; Iwasaki, Kengo; Izumi, Yuichi

2017-01-01

The aim of this study is to investigate the mechanisms linking high glucose to gingival wound healing. Bilateral wounds were created in the palatal gingiva adjacent to maxillary molars of control rats and rats with streptozotocin-induced diabetes. After evaluating postsurgical wound closure by digital imaging, the maxillae including wounds were resected for histological examinations. mRNA expressions of angiogenesis, inflammation, and oxidative stress markers in the surgical sites were quantified by real-time polymerase chain reaction. Primary fibroblast culture from the gingiva of both rats was performed in high glucose and normal medium. In vitro wound healing and cell proliferation assays were performed. Oxidative stress marker mRNA expressions and reactive oxygen species production were measured. Insulin resistance was evaluated via PI3K/Akt and MAPK/Erk signaling following insulin stimulation using Western blotting. To clarify oxidative stress involvement in high glucose culture and cells of diabetic rats, cells underwent N-acetyl-L-cysteine treatment; subsequent Akt activity was measured. Wound healing in diabetic rats was significantly delayed compared with that in control rats. Nox1, Nox2, Nox4, p-47, and tumor necrosis factor-α mRNA levels were significantly higher at baseline in diabetic rats than in control rats. In vitro study showed that cell proliferation and migration significantly decreased in diabetic and high glucose culture groups compared with control groups. Nox1, Nox2, Nox4, and p47 expressions and reactive oxygen species production were significantly higher in diabetic and high glucose culture groups than in control groups. Akt phosphorylation decreased in the high glucose groups compared with the control groups. Erk1/2 phosphorylation increased in the high glucose groups, with or without insulin treatment, compared with the control groups. Impaired Akt phosphorylation partially normalized after antioxidant N-acetyl-L-cysteine treatment. Thus, delayed gingival wound healing in diabetic rats occurred because of impaired fibroblast proliferation and migration. Fibroblast dysfunction may occur owing to high glucose-induced insulin resistance via oxidative stress.

Oxidation mechanism of T91 steel in liquid lead-bismuth eutectic: with consideration of internal oxidation

PubMed Central

Ye, Zhongfei; Wang, Pei; Dong, Hong; Li, Dianzhong; Zhang, Yutuo; Li, Yiyi

2016-01-01

Clarification of the microscopic events that occur during oxidation is of great importance for understanding and consequently controlling the oxidation process. In this study the oxidation product formed on T91 ferritic/martensitic steel in oxygen saturated liquid lead-bismuth eutectic (LBE) at 823 K was characterized at the nanoscale using focused-ion beam and transmission electron microscope. An internal oxidation zone (IOZ) under the duplex oxide scale has been confirmed and characterized systematically. Through the microscopic characterization of the IOZ and the inner oxide layer, the micron-scale and nano-scale diffusion of Cr during the oxidation in LBE has been determined for the first time. The micron-scale diffusion of Cr ensures the continuous advancement of IOZ and inner oxide layer, and nano-scale diffusion of Cr gives rise to the typical appearance of the IOZ. Finally, a refined oxidation mechanism including the internal oxidation and the transformation of IOZ to inner oxide layer is proposed based on the discussion. The proposed oxidation mechanism succeeds in bridging the gap between the existing models and experimental observations. PMID:27734928

Structural, electronic and chemical properties of metal/oxide and oxide/oxide interfaces and thin film structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lad, Robert J.

1999-12-14

This project focused on three different aspects of oxide thin film systems: (1) Model metal/oxide and oxide/oxide interface studies were carried out by depositing ultra-thin metal (Al, K, Mg) and oxide (MgO, AlO{sub x}) films on TiO{sub 2}, NiO and {alpha}-Al{sub 2}O{sub 3} single crystal oxide substrates. (2) Electron cyclotron resonance (ECR) oxygen plasma deposition was used to fabricate AlO{sub 3} and ZrO{sub 2} films on sapphire substrates, and film growth mechanisms and structural characteristics were investigated. (3) The friction and wear characteristics of ZrO{sub 2} films on sapphire substrates in unlubricated sliding contact were studied and correlated with filmmore » microstructure. In these studies, thin film and interfacial regions were characterized using diffraction (RHEED, LEED, XRD), electron spectroscopies (XPS, UPS, AES), microscopy (AFM) and tribology instruments (pin-on-disk, friction microprobe, and scratch tester). By precise control of thin film microstructure, an increased understanding of the structural and chemical stability of interface regions and tribological performance of ultra-thin oxide films was achieved in these important ceramic systems.« less

STABILIZED RARE EARTH OXIDES FOR A CONTROL ROD AND METHOD OF PREPARATION

DOEpatents

McNees, R.A.; Potter, R.A.

1964-01-14

A method is given for preparing mixed oxides of the formula MR/sub x/O/ sub 12/ wherein M is tungsten or molybdenum and R is a rare earth in the group consisting of samarium, europium, dysprosium, and gadolinium and x is 4 to 5. Oxides of this formula, and particularly the europiumcontaining species, are useful as control rod material for water-cooled nuclear reactors owing to their stability, favorable nuclear properties, and resistance to hydration. These oxides may be utilized as a dispersion in a stainlesssteel matrix. Preparation of these oxides is effected by blending tungsten oxide or molybdenum oxide with a rare earth oxide, compressing the mixture, and firing at an elevated temperature in an oxygen-containing atmosphere. (AEC)

Nitrogen Removal over Nitrite by Aeration Control in Aerobic Granular Sludge Sequencing Batch Reactors

PubMed Central

Lochmatter, Samuel; Maillard, Julien; Holliger, Christof

2014-01-01

This study investigated the potential of aeration control for the achievement of N-removal over nitrite with aerobic granular sludge in sequencing batch reactors. N-removal over nitrite requires less COD, which is particularly interesting if COD is the limiting parameter for nutrient removal. The nutrient removal performances for COD, N and P have been analyzed as well as the concentration of nitrite-oxidizing bacteria in the granular sludge. Aeration phase length control combined with intermittent aeration or alternate high-low DO, has proven to be an efficient way to reduce the nitrite-oxidizing bacteria population and hence achieve N-removal over nitrite. N-removal efficiencies of up to 95% were achieved for an influent wastewater with COD:N:P ratios of 20:2.5:1. The total N-removal rate was 0.18 kgN·m−3·d−1. With N-removal over nitrate the N-removal was only 74%. At 20 °C, the nitrite-oxidizing bacteria concentration decreased by over 95% in 60 days and it was possible to switch from N-removal over nitrite to N-removal over nitrate and back again. At 15 °C, the nitrite-oxidizing bacteria concentration decreased too but less, and nitrite oxidation could not be completely suppressed. However, the combination of aeration phase length control and high-low DO was also at 15 °C successful to maintain the nitrite pathway despite the fact that the maximum growth rate of nitrite-oxidizing bacteria at temperatures below 20 °C is in general higher than the one of ammonium-oxidizing bacteria. PMID:25006970

Nitrification and its influence on biogeochemical cycles from the equatorial Pacific to the Arctic Ocean

PubMed Central

Shiozaki, Takuhei; Ijichi, Minoru; Isobe, Kazuo; Hashihama, Fuminori; Nakamura, Ken-ichi; Ehama, Makoto; Hayashizaki, Ken-ichi; Takahashi, Kazutaka; Hamasaki, Koji; Furuya, Ken

2016-01-01

We examined nitrification in the euphotic zone, its impact on the nitrogen cycles, and the controlling factors along a 7500 km transect from the equatorial Pacific Ocean to the Arctic Ocean. Ammonia oxidation occurred in the euphotic zone at most of the stations. The gene and transcript abundances for ammonia oxidation indicated that the shallow clade archaea were the major ammonia oxidizers throughout the study regions. Ammonia oxidation accounted for up to 87.4% (average 55.6%) of the rate of nitrate assimilation in the subtropical oligotrophic region. However, in the shallow Bering and Chukchi sea shelves (bottom ⩽67 m), the percentage was small (0–4.74%) because ammonia oxidation and the abundance of ammonia oxidizers were low, the light environment being one possible explanation for the low activity. With the exception of the shallow bottom stations, depth-integrated ammonia oxidation was positively correlated with depth-integrated primary production. Ammonia oxidation was low in the high-nutrient low-chlorophyll subarctic region and high in the Bering Sea Green Belt, and primary production in both was influenced by micronutrient supply. An ammonium kinetics experiment demonstrated that ammonia oxidation did not increase significantly with the addition of 31–1560 nm ammonium at most stations except in the Bering Sea Green Belt. Thus, the relationship between ammonia oxidation and primary production does not simply indicate that ammonia oxidation increased with ammonium supply through decomposition of organic matter produced by primary production but that ammonia oxidation might also be controlled by micronutrient availability as with primary production. PMID:26918664

Total Oxidant and Antioxidant Status in Prepubertal Children with Obesity.

PubMed

Rowicka, Grażyna; Dyląg, Hanna; Ambroszkiewicz, Jadwiga; Riahi, Agnieszka; Weker, Halina; Chełchowska, Magdalena

2017-01-01

Obesity is accompanied by the formation of oxygen free radicals, whose intensified activity without effective defense mechanisms can lead to oxidative stress and related complications. We evaluated the presence of oxidative stress in obese prepubertal children. The study included 83 healthy children aged 2-10 years (62 with obesity and 21 nonobese controls). Total oxidant capacity (TOC), total antioxidant capacity (TAC), oxidized low-density lipoprotein (ox-LDL), lipid parameters, glucose, and C-reactive protein (CRP) were measured in serum. Oxidative stress index (OSI) was calculated. Serum TOC concentration was significantly higher ( p < 0.05) and TAC concentration was lower ( p < 0.05) in obese children. OSI was higher ( p < 0.01) in obese subjects compared with controls. CRP levels were normal in all children, but median CRP value was higher ( p < 0.01) and HDL cholesterol levels were lower ( p < 0.05) in the obese group. We found a significant negative correlation between TAC and ox-LDL concentrations ( r = -0.27, p < 0.05) in obese children. Furthermore, obesity duration was positively correlated with TOC level ( r = 0.32, p < 0.05) in this group. Obesity-related oxidative stress already occurs in prepubescence. Early obesity diagnosis and the necessary therapeutic activity implementation is a vital strategy for the prophylaxis of free radical damage and related multiorgan complications.

Bacopa monnieri as an Antioxidant Therapy to Reduce Oxidative Stress in the Aging Brain

PubMed Central

Simpson, Tamara; Pase, Matthew; Stough, Con

2015-01-01

The detrimental effect of neuronal cell death due to oxidative stress and mitochondrial dysfunction has been implicated in age-related cognitive decline and neurodegenerative disorders such as Alzheimer's disease. The Indian herb Bacopa monnieri is a dietary antioxidant, with animal and in vitro studies indicating several modes of action that may protect the brain against oxidative damage. In parallel, several studies using the CDRI08 extract have shown that extracts of Bacopa monnieri improve cognitive function in humans. The biological mechanisms of this cognitive enhancement are unknown. In this review we discuss the animal studies and in vivo evidence for Bacopa monnieri as a potential therapeutic antioxidant to reduce oxidative stress and improve cognitive function. We suggest that future studies incorporate neuroimaging particularly magnetic resonance spectroscopy into their randomized controlled trials to better understand whether changes in antioxidant status in vivo cause improvements in cognitive function. PMID:26413126

Application of confocal Raman micro-spectroscopy for label-free monitoring of oxidative stress in living bronchial cells

NASA Astrophysics Data System (ADS)

Surmacki, Jakub M.; Quirós Gonzalez, Isabel; Bohndiek, Sarah E.

2018-02-01

Oxidative stress in cancer is implicated in tumor progression, being associated with increased therapy resistance and metastasis. Conventional approaches for monitoring oxidative stress in tissue such as high-performance liquid chromatography and immunohistochemistry are bulk measurements and destroy the sample, meaning that longitudinal monitoring of cancer cell heterogeneity remains elusive. Raman spectroscopy has the potential to overcome this challenge, providing a chemically specific, label free readout from single living cells. Here, we applied a standardized protocol for label-free confocal Raman micro-spectroscopy in living cells to monitor oxidative stress in bronchial cells. We used a quartz substrate in a commercial cell chamber contained within a microscope incubator providing culture media for cell maintenance. We studied the effect of a potent reactive oxygen species inducer, tert-butyl hydroperoxide (TBHP), and antioxidant, N-acetyl-L-cysteine (NAC) on living cells from a human bronchial epithelial cells (HBEC). We found that the Raman bands corresponding to nucleic acids, proteins and lipids were significantly different (p<0.05) for control, TBHP, and NAC. Encouragingly, partial least squares discriminant analysis applied to our data showed high sensitivity and specificity for identification of control (87.3%, 71.7%), NAC (92.3%, 85.1%) and TBHP (86.9%, 92.9%). These results suggest that confocal Raman micro-spectroscopy may be able to monitor the biological impact of oxidative and reductive processes in cells, hence enabling longitudinal studies of oxidative stress in therapy resistance and metastasis at the single cell level.

Minimizing nitrous oxide in biological nutrient removal from municipal wastewater by controlling copper ion concentrations.

PubMed

Zhu, Xiaoyu; Chen, Yinguang; Chen, Hong; Li, Xiang; Peng, Yongzhen; Wang, Shuying

2013-02-01

In this study, nitrous oxide (N(2)O) production during biological nutrient removal (BNR) from municipal wastewater was reported to be remarkably reduced by controlling copper ion (Cu(2+)) concentration. Firstly, it was observed that the addition of Cu(2+) (10-100 μg/L) reduced N(2)O generation by 54.5-73.2 % and improved total nitrogen removal when synthetic wastewater was treated in an anaerobic-aerobic (with low dissolved oxygen) BNR process. Then, the roles of Cu(2+) were investigated. The activities of nitrite and nitrous oxide reductases were increased by Cu(2+) addition, which accelerated the bio-reductions of both nitrite to nitric oxide (NO (2) (-)  → NO) and nitrous oxide to nitrogen gas (N(2)O → N(2)). The quantitative real-time polymerase chain reaction assay indicated that Cu(2+) addition increased the number of N(2)O reducing denitrifiers. Further investigation showed that more polyhydoxyalkanoates were utilized in the Cu(2+)-added system for denitrification. Finally, the feasibility of reducing N(2)O generation by controlling Cu(2+) was examined in two other BNR processes treating real municipal wastewater. As the Cu(2+) in municipal wastewater is usually below 10 μg/L, according to this study, the supplement of influent Cu(2+) to a concentration of 10-100 μg/L is beneficial to reduce N(2)O emission and improve nitrogen removal when sludge concentration in the BNR system is around 3,200 mg/L.

Effect of chronic exposure to aspartame on oxidative stress in the brain of albino rats.

PubMed

Iyyaswamy, Ashok; Rathinasamy, Sheeladevi

2012-09-01

This study was aimed at investigating the chronic effect of the artificial sweetener aspartame on oxidative stress in brain regions of Wistar strain albino rats. Many controversial reports are available on the use of aspartame as it releases methanol as one of its metabolite during metabolism. The present study proposed to investigate whether chronic aspartame (75 mg/kg) administration could release methanol and induce oxidative stress in the rat brain. To mimic the human methanol metabolism, methotrexate (MTX)-treated rats were included to study the aspartame effects. Wistar strain male albino rats were administered with aspartame orally and studied along with controls and MTX-treated controls. The blood methanol level was estimated, the animal was sacrificed and the free radical changes were observed in brain discrete regions by assessing the scavenging enzymes, reduced glutathione, lipid peroxidation (LPO) and protein thiol levels. It was observed that there was a significant increase in LPO levels, superoxide dismutase (SOD) activity, GPx levels and CAT activity with a significant decrease in GSH and protein thiol. Moreover, the increases in some of these enzymes were region specific. Chronic exposure of aspartame resulted in detectable methanol in blood. Methanol per se and its metabolites may be responsible for the generation of oxidative stress in brain regions.

Polycystic ovary syndrome offspring display increased oxidative stress markers comparable to gestational diabetes offspring.

PubMed

Boutzios, Georgios; Livadas, Sarantis; Piperi, Christina; Vitoratos, Nicolaos; Adamopoulos, Christos; Hassiakos, Dimitrios; Iavazzo, Christos; Diamanti-Kandarakis, Evanthia

2013-03-01

To study oxidative stress (OS) markers on neonates. The specific aim was to evaluate advanced glycation end products (AGEs) and advanced oxidation protein products (AOPPs) serum levels along with the hormonal/metabolic profile and their possible relationship in a cohort of polycystic ovary syndrome PCOS(N) and gestational diabetes GDM(N) neonates and their mothers PCOS(M) and GDM(M). Prospective controlled study. Academic medical center. The study population comprised 151 mother/neonate pairs. Diet and/or insulin administration in GDM(M). Anthropometric, metabolic, hormonal parameters, and OS markers. The AGEs and AOPPs were higher in PCOS(M) and GDM(M) compared with controls (M). The same significant difference was observed in the corresponding groups of neonates. A strong relationship between mothers and neonates regarding AGEs (r = 0.605) and AOPPs levels (r = 0.735) was disclosed. Analogous findings were observed regarding androgens and insulin resistance in mothers and neonates, respectively. The present study demonstrated that in PCOS(N), the OS status was similar to that of GDM(N) and strongly associated with their mothers' oxidative status. These findings may have clinical implications, as exposure of PCOS(N) to high OS levels during pregnancy could affect several health issues of neonates. Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Plasma lipid peroxidation and erythrocyte antioxidant enzymes status in workers exposed to cadmium.

PubMed

Babu, Kalahasthi Ravi; Rajmohan, Hirehal Raghavendra Rao; Rajan, Bagalur Krishna Murthy; Kumar, Karuna M

2006-09-01

Cadmium (Cd) is a corrosion-resistant metal, used extensively for electroplating in the automobile, electronic and aerospace industry. Only a few studies are available regarding Cd-induced oxidative stress in animals, but no reports are available regarding the effects of Cd on oxidative stress during occupational exposure. The present study was carried out to determine the plasma lipid peroxidation and erythrocyte antioxidant enzymes status in workers exposed to Cd during electroplating. 50 subjects exposed to Cd during electroplating formed the study group. An equal number of age-sex matched subjects, working in the administrative section, formed the control group. Urinary Cd levels were determined using the flameless atomic absorption spectrophotometer. Plasma lipid peroxidation and erythrocyte antioxidant enzymes were determined using spectrophotometric methods. A significant increase of plasma lipid peroxidation and a significant decrease of superoxide dismutase and glutathione peroxidase levels were noted in the study group compared with the control group. The level of plasma lipid peroxidation was positively and erythrocyte antioxidant enzymes were negatively and significantly associated with Cd levels in urine. Multiple regression analysis assessed the oxidative stress associated with Cd and other lifestyle confounding factors, such as age, body mass index, the consumption of vegetables, coffee, tea, smoking and alcohol. Analysis showed that the lifestyle confounding factors viz; smoking, body mass index and urinary Cd levels > 5 microg/g of creatinine, were significantly associated with oxidative stress. The results of the present study suggest that increased plasma lipid peroxidation and decreased superoxide dismutase levels could be used as biomarkers of oxidative stress in cadmium-exposed workers.

Role of oxidative stress enzymes in open-angle glaucoma.

PubMed

Yildirim, O; Ateş, N A; Ercan, B; Muşlu, N; Unlü, A; Tamer, L; Atik, U; Kanik, A

2005-05-01

To investigate the role of oxidative stress and lipid peroxidation in the pathogenesis of primary open-angle glaucoma (POAG). The activities of myeloperoxidase (MPO), catalase (CAT), and the levels of plasma malondialdehyde (MDA) were measured in 40 (15 men and 25 women) patients with POAG and 60 (30 men and 30 women) healthy controls. There was no significant difference in the activities of CAT and MPO between the POAG patients and the controls. However, the plasma MDA level was significantly higher in patients than the controls. The results of this preliminary study suggest that the possible alterations of plasma MDA levels may be associated with the pathogenesis of POAG, but further research is needed to understand the role of oxidative damage in this important disorder of aging.

Cognitive-behavioral therapy for sleep disturbance decreases inflammatory cytokines and oxidative stress in hemodialysis patients.

PubMed

Chen, Hung-Yuan; Cheng, I-Chih; Pan, Yi-Ju; Chiu, Yen-Ling; Hsu, Shih-Ping; Pai, Mei-Fen; Yang, Ju-Yeh; Peng, Yu-Sen; Tsai, Tun-Jun; Wu, Kwan-Dun

2011-08-01

Sleep disturbance is common in dialysis patients and is associated with the development of enhanced inflammatory responses. Cognitive-behavioral therapy is effective for sleep disturbance and reduces inflammation experienced by peritoneal dialysis patients; however, this has not been studied in hemodialysis patients. To determine whether alleviation of sleep disturbance in hemodialysis patients also leads to less inflammation, we conducted a randomized controlled interventional study of 72 sleep-disturbed hemodialysis patients. Within this patient cohort, 37 received tri-weekly cognitive-behavioral therapy lasting 6 weeks and the remaining 35, who received sleep hygiene education, served as controls. The adjusted post-trial primary outcome scores of the Pittsburgh Sleep Quality Index, the Fatigue Severity Scale, the Beck Depression Inventory, and the Beck Anxiety Inventory were all significantly improved from baseline by therapy compared with the control group. The post-trial secondary outcomes of high-sensitive C-reactive protein, IL-18, and oxidized low-density lipoprotein levels significantly declined with cognitive-behavioral therapy in comparison with the control group. Thus, our results suggest that cognitive-behavioral therapy is effective for correcting disorganized sleep patterns, and for reducing inflammation and oxidative stress in hemodialysis patients.

In Situ Probing and Synthetic Control of Cationic Ordering in Ni-Rich Layered Oxide Cathodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Jianqing; Zhang, Wei; Huq, Ashfia

Ni-rich layered oxides (LiNi1-xMxO2; M = Co, Mn, ...) are appealing alternatives to conventional LiCoO2 as cathodes in Li-ion batteries for automobile and other large-scale applications due to their high theoretical capacity and low cost. However, preparing stoichiometric LiNi1-xMxO2 with ordered layer structure and high reversible capacity, has proven difficult due to cation mixing in octahedral sites. Herein, in situ studies of synthesis reactions and the associated structural ordering in preparing LiNiO2 and the Co-substituted variant, LiNi0.8Co0.2O2, are made, to gain insights into synthetic control of the structure and electrochemical properties of Ni-rich layered oxides. Results from this study indicatemore » a direct transformation of the intermediate from the rock salt structure into hexagonal phase, and during the process, Co substitution facilities the nucleation of a Co-rich layered phase at low temperatures and subsequent growth and stabilization of solid solution Li(Ni, Co)O-2 upon further heat treatment. Optimal conditions are identified from the in situ studies and utilized to obtain stoichiometric LiNi0.8Co0.2O2 that exhibits high capacity (up to 200 mA h g(-1) ) with excellent retention. The findings shed light on designing high performance Ni-rich layered oxide cathodes through synthetic control of the structural ordering in the materials.« less

Paraoxonase-1 activities in children and adolescents with type 1 diabetes mellitus.

PubMed

Craciun, Elena C; Leucuta, Daniel C; Rusu, Razvan L; David, Bianca A; Cret, Victoria; Dronca, Eleonora

2016-01-01

Paraoxonase-1 is an HDL-associated esterase that acts as an anti-atherogenic agent by protecting LDL from oxidation. This study investigates paraoxonase-1 activities in children and adolescents with type 1 diabetes mellitus and possible associations with other biochemical markers. The study enrolled 82 children and adolescents with type 1 diabetes mellitus and 41 controls with similar age and gender distribution. Serum paraoxonase-1 arylesterase and salt-stimulated paraoxonase activities were assessed by measuring the rates of phenyl acetate and paraoxon hydrolysis, respectively; paraoxonase-1 lactonase activity and oxidized LDL were assessed by a pH-sensitive colorimetric assay and ELISA, respectively. Glycated haemoglobin HbA1c and lipid profile were assayed with an immunoturbidimetric method and commercially available kits, respectively. We found lower paraoxonase-1 activities in diabetics when compared to controls. The decrease was statistically significant only for the lactonase activity, the difference being higher when referring to the subgroup with poor glycaemic control. The lactonase activity/HDL ratio was also lower in diabetics vs. controls, but without statistical significance. Both lactonase and arylesterase activities were negatively correlated with HbA1c in diabetics, but only the latter was statistically significant (ρ = -0.21, P = 0.055; ρ = -0.24, P = 0.03, respectively). A correlation coefficient of ρ = 0.196 (P = 0.078) was found between oxidized LDL and HbA1c. All paraoxonase-1 activities were lower in diabetic children and adolescents, but only the decrease in the lactonase activity was statistically significant. Although lipid profile and glycaemic control were altered in diabetics, no differences were observed between groups regarding oxidized LDL level.

Biomarkers of oxidative stress in electroplating workers exposed to hexavalent chromium.

PubMed

Pan, Chih-Hong; Jeng, Hueiwang Anna; Lai, Ching-Huang

2018-01-01

This study evaluates levels of biomarkers of oxidative DNA damage and lipid peroxidation in 105 male workers at 16 electroplating companies who had been exposed to hexavalent chromium (Cr(VI)). The study participants were 230 non-smoking male workers, comprising 105 electroplating workers who had been exposed to chromium and 125 control subjects who performed office tasks. Personal air samples, spot urine samples, hair samples, fingernail samples and questionnaires were used to quantify exposure to Cr(VI), oxidative DNA damage, lipid peroxidation, and environmental pollutants. Both the geometric mean personal concentrations of Cr(VI) of the Cr-exposed workers and the total Cr concentrations in the air to which they were exposed significantly exceeded those for the control subjects. The geometric mean concentrations of Cr in urine, hair and fingernails, and the urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), and malondialdehyde (MDA) levels in the Cr(VI) exposed workers exceeded those in the control subjects. Daily cumulative Cr(VI) exposure and urinary Cr were significantly correlated with urinary 8-OHdG levels following adjustments for covariates. A ten-fold increase in urinary Cr level was associated with a 1.73-fold increase in urinary 8-OHdG level. Daily cumulative Cr(VI) exposure and urinary Cr level were significantly correlated with urinary MDA level following adjustments for covariates. A ten-fold increase in urinary Cr was associated with a 1.45-fold increase in urinary MDA. Exposure to Cr(VI) increased oxidative DNA injury and the oxidative deterioration of lipids in electroplating workers.

Production of Sn/SnO2/MWCNT composites by plasma oxidation after thermal evaporation from pure Sn targets onto buckypapers.

PubMed

Alaf, M; Gultekin, D; Akbulut, H

2012-12-01

In this study, tin/tinoxide/multi oxide/multi walled carbon nano tube (Sn/SnO2/MWCNT) composites were produced by thermal evaporation and then subsequent plasma oxidation. Buckypapers having controlled porosity were prepared by vacuum filtration from functionalized MWCNTs. Pure metallic tin was thermally evaporated on the buckypapers in argon atmosphere with different thicknesses. It was determined that the evaporated pure tin nano crystals were mechanically penetrated into pores of buckypaper to form a nanocomposite. The tin/MWCNT composites were subjected to plasma oxidation process at oxygen/argon gas mixture. Three different plasma oxidation times (30, 45 and 60 minutes) were used to investigate oxidation and physical and microstructural properties. The effect of coating thickness and oxidation time was investigated to understand the effect of process parameters on the Sn and SnO2 phases after plasma oxidation. Quantitative phase analysis was performed in order to determine the relative phase amounts. The structural properties were studied by field-emission gun scanning electron microscopy (FEG-SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD).

Effect of Machining Parameters on Oxidation Behavior of Mild Steel

NASA Astrophysics Data System (ADS)

Majumdar, P.; Shekhar, S.; Mondal, K.

2015-01-01

This study aims to find out a correlation between machining parameters, resultant microstructure, and isothermal oxidation behavior of lathe-machined mild steel in the temperature range of 660-710 °C. The tool rake angles "α" used were +20°, 0°, and -20°, and cutting speeds used were 41, 232, and 541 mm/s. Under isothermal conditions, non-machined and machined mild steel samples follow parabolic oxidation kinetics with activation energy of 181 and ~400 kJ/mol, respectively. Exaggerated grain growth of the machined surface was observed, whereas, the center part of the machined sample showed minimal grain growth during oxidation at higher temperatures. Grain growth on the surface was attributed to the reduction of strain energy at high temperature oxidation, which was accumulated on the sub-region of the machined surface during machining. It was also observed that characteristic surface oxide controlled the oxidation behavior of the machined samples. This study clearly demonstrates the effect of equivalent strain, roughness, and grain size due to machining, and subsequent grain growth on the oxidation behavior of the mild steel.

Metal Catalyst for Low-Temperature Growth of Controlled Zinc Oxide Nanowires on Arbitrary Substrates

PubMed Central

Kim, Baek Hyun; Kwon, Jae W.

2014-01-01

Zinc oxide nanowires generated by hydrothermal method present superior physical and chemical characteristics. Quality control of the growth has been very challenging and controlled growth is only achievable under very limited conditions using homogeneous seed layers with high temperature processes. Here we show the controlled ZnO nanowire growth on various organic and inorganic materials without the requirement of a homogeneous seed layer and a high temperature process. We also report the discovery of an important role of the electronegativity in the nanowire growth on arbitrary substrates. Using heterogeneous metal oxide interlayers with low-temperature hydrothermal methods, we demonstrate well-controlled ZnO nanowire arrays and single nanowires on flat or curved surfaces. A metal catalyst and heterogeneous metal oxide interlayers are found to determine lattice-match with ZnO and to largely influence the controlled alignment. These findings will contribute to the development of novel nanodevices using controlled nanowires. PMID:24625584

Intraperitoneal curcumin decreased lung, renal and heart injury in abdominal aorta ischemia/reperfusion model in rat.

PubMed

Aydin, Mehmet Salih; Caliskan, Ahmet; Kocarslan, Aydemir; Kocarslan, Sezen; Yildiz, Ali; Günay, Samil; Savik, Emin; Hazar, Abdussemet; Yalcin, Funda

2014-01-01

Previous studies have demonstrated that curcumin (CUR) has protective effects against ischemia reperfusion injury to various organs. We aimed to determine whether CUR has favorable effects on tissues and oxidative stress in abdominal aorta ischemia-reperfusion injury. Thirty rats were divided into three groups as sham, control and treatment (CUR) group. Control and CUR groups underwent abdominal aorta ischemia for 60 min followed by a 120 min period of reperfusion. In the CUR group, CUR was given 5 min before reperfusion at a dose of 200 mg/kg via an intraperitoneal route. Total antioxidant capacity (TAC), total oxidative status (TOS), and oxidative stress index (OSI) in blood serum were measured, and lung, renal and heart tissue histopathology were evaluated with light microscopy. TOS and OSI activity in blood samples were statistically decreased in sham and CUR groups compared to the control group (p < 0.001 for TOS and OSI). Renal, lung, heart injury scores of sham and CUR groups were statistically decreased compared to control group (p < 0.001 for all comparisons). Histopathological examination revealed less severe lesions in CUR group than in the control group. CUR administered intraperitoneally was effective in reducing oxidative stress and histopathologic injury in an acute abdominal aorta I/R rat model. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Biomarkers of oxidative stress study V: ozone exposure of rats and its effect on lipids, proteins, and DNA in plasma and urine.

PubMed

Kadiiska, Maria B; Basu, Samar; Brot, Nathan; Cooper, Christopher; Saari Csallany, A; Davies, Michael J; George, Magdalene M; Murray, Dennis M; Jackson Roberts, L; Shigenaga, Mark K; Sohal, Rajindar S; Stocker, Roland; Van Thiel, David H; Wiswedel, Ingrid; Hatch, Gary E; Mason, Ronald P

2013-08-01

Ozone exposure effect on free radical-catalyzed oxidation products of lipids, proteins, and DNA in the plasma and urine of rats was studied as a continuation of the international Biomarker of Oxidative Stress Study (BOSS) sponsored by NIEHS/NIH. The goal was to identify a biomarker for ozone-induced oxidative stress and to assess whether inconsistent results often reported in the literature might be due to the limitations of the available methods for measuring the various types of oxidative products. The time- and dose-dependent effects of ozone exposure on rat plasma lipid hydroperoxides, malondialdehyde, F2-isoprostanes, protein carbonyls, methionine oxidation, and tyrosine- and phenylalanine oxidation products, as well as urinary malondialdehyde and F2-isoprostanes were investigated with various techniques. The criterion used to recognize a marker in the model of ozone exposure was that a significant effect could be identified and measured in a biological fluid seen at both doses at more than one time point. No statistically significant differences between the experimental and the control groups at either ozone dose and time point studied could be identified in this study. Tissue samples were not included. Despite all the work accomplished in the BOSS study of ozone, no available product of oxidation in biological fluid has yet met the required criteria of being a biomarker. The current negative findings as a consequence of ozone exposure are of great importance, because they document that in complex systems, as the present in vivo experiment, the assays used may not provide meaningful data of ozone oxidation, especially in human studies. Published by Elsevier Inc.

Biomarkers of Oxidative Stress Study V: Ozone exposure of rats and its effect on lipids, proteins and DNA in plasma and urine

PubMed Central

Kadiiska, Maria B.; Basu, Samar; Brot, Nathan; Cooper, Christopher; Csallany, A. Saari; Davies, Michael J.; George, Magdalene M.; Murray, Dennis M.; Roberts, L. Jackson; Shigenaga, Mark K.; Sohal, Rajindar S.; Stocker, Roland; Van Thiel, David H.; Wiswedel, Ingrid; Hatch, Gary E.; Mason, Ronald P.

2014-01-01

Ozone exposure effect on free radical-catalyzed oxidation products of lipids, proteins and DNA in the plasma and urine of rats was studied as a continuation of the international Biomarker of Oxidative Stress Study (BOSS) sponsored by NIEHS/NIH. The goal was to identify a biomarker for ozone-induced oxidative stress and to assess whether inconsistent results often reported in the literature might be due to the limitations of the available methods for measuring the various types of oxidative products. The time and dose-dependent effects of ozone exposure on rat plasma lipid hydroperoxides, malondialdehyde, F2-isoprostanes, protein carbonyls, methionine oxidation, tyrosine- and phenylalanine oxidation products, as well as urinary malondialdehyde and F2-isoprostanes were investigated with various techniques. The criterion used to recognize a marker in the model of ozone exposure was that a significant effect could be identified and measured in a biological fluid seen at both doses at more than one time point. No statistically significant differences between the experimental and control groups at either ozone dose and time point studied could be identified in this study. Tissue samples were not included. Despite all the work accomplished in the BOSS study of ozone, no available product of oxidation in biological fluid has yet met the required criteria of being a biomarker. The current negative findings as a consequence of ozone exposure are of great importance, because they document that in complex systems, as the present in vivo experiment, the assays used may not provide meaningful data of ozone oxidation, especially in human studies. PMID:23608465

Surface Charge at the Oxide/Electrolyte Interface: Toward Optimization of Electrolyte Composition for Treatment of Aluminum and Magnesium by Plasma Electrolytic Oxidation.

PubMed

Nominé, Alexandre; Martin, Julien; Noël, Cédric; Henrion, Gérard; Belmonte, Thierry; Bardin, Ilya V; Lukeš, Petr

2016-02-09

Controlling microdischarges in plasma electrolytic oxidation is of great importance in order to optimize coating quality. The present study highlights the relationship between the polarity at which breakdown occurs and the electrolyte pH as compared with the isoelectric point (IEP). It is found that working at a pH higher than the IEP of the grown oxide prevents the buildup of detrimental cathodic discharges. The addition of phosphates results in a shift in the IEP to a lower value and therefore promotes anodic discharges at the expense of cathodic ones.

Reactive Oxygen Species Inactivation of Surfactant Involves Structural and Functional Alterations to Surfactant Proteins SP-B and SP-C

PubMed Central

Rodríguez-Capote, Karina; Manzanares, Dahis; Haines, Thomas; Possmayer, Fred

2006-01-01

Exposing bovine lipid extract surfactant (BLES), a clinical surfactant, to reactive oxygen species arising from hypochlorous acid or the Fenton reaction resulted in an increase in lipid (conjugated dienes, lipid aldehydes) and protein (carbonyls) oxidation products and a reduction in surface activity. Experiments where oxidized phospholipids (PL) were mixed with BLES demonstrated that this addition hampered BLES biophysical activity. However the effects were only moderately greater than with control PL. These results imply a critical role for protein oxidation. BLES oxidation by either method resulted in alterations in surfactant proteins SP-B and SP-C, as evidenced by altered Coomassie blue and silver staining. Western blot analyses showed depressed reactivity with specific antibodies. Oxidized SP-C showed decreased palmitoylation. Reconstitution experiments employing PL, SP-B, and SP-C isolated from control or oxidized BLES demonstrated that protein oxidation was more deleterious than lipid oxidation. Furthermore, addition of control SP-B can improve samples containing oxidized SP-C, but not vice versa. We conclude that surfactant oxidation arising from reactive oxygen species generated by air pollution or leukocytes interferes with surfactant function through oxidation of surfactant PL and proteins, but that protein oxidation, in particular SP-B modification, produces the major deleterious effects. PMID:16443649

Evaluation of cell wall damage by dimethyl sulfoxide in Candida species.

PubMed

León-García, María Cristina; Ríos-Castro, Emmanuel; López-Romero, Everardo; Cuéllar-Cruz, Mayra

2017-10-01

Studies dealing with the response of microorganisms to oxidative stress require the dissolution of oxidant agents in an appropriate solvent. A commonly used medium is dimethyl sulfoxide, which has been considered as an innocuous polar solvent. However, we have observed significant differences between control, untreated cells and those receiving increasing amounts of the oxidant and hence increasing amounts of DMSO, to the maximum allowed of 1%. Here we show that, while this solvent does not influence yeast cell viability, it does affect expression of cell wall proteins as well as catalase activity. Therefore, its use in future studies of oxidative stress as an innocuous solvent should be reconsidered. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Methane and Methanol Oxidation in Supercritical Water: Chemical Kinetics and Hydrothermal Flame Studies

DTIC Science & Technology

1996-01-01

water at 270 bar and at temperatures from 390 to 442 ’C. The initial methane concentration was nominally 0.15 gmol/L, a level representa- tive of...compounds appropriate for treatment with SCWO technology (Modell, 1989). Since then, the need to understand reaction chemistry has motivated extensive...understand the physics and chemistry controlling oxidation in supercritical water; to contribute to combustion science by performing fundamental studies in a

A Review of the Effect of Dietary Composition on Fasting Substrate Oxidation in Healthy and Overweight Subjects.

PubMed

Whelan, Megan E; Wright, Olivia R L; Hickman, Ingrid J

2016-01-01

The purpose of this review was to assess existing evidence on the effects of chronic dietary macronutrient composition on substrate oxidation during a fasted state in healthy and overweight subjects. A systematic review of studies was conducted across five databases. Studies were included if they were English language studies of human adults, ≥19 years, used indirect calorimetry (ventilated hood technique), specified dietary macronutrient composition, and measured substrate oxidation. There was no evidence that variations of a typical, non-experimental diet influenced rate or ratio of substrate utilization, however there may be an upper and lower threshold for when macronutrient composition may directly alter preferences for fuel oxidation rates during a fasted state. This review indicates that macronutrient composition of a wide range of typical, non-experimental dietary fat and carbohydrate intakes has no effect on fasting substrate oxidation. This suggests that strict control of dietary intake prior to fasting indirect calorimetry measurements may be an unnecessary burden for study participants. Further research into the effects of long-term changes in isocaloric macronutrient shift is required.

Antipsychotic Treatment Reduces Indices of Oxidative Stress in First-Episode Psychosis Patients

PubMed Central

Haring, Liina; Vasar, Eero; Vasar, Veiko; Zilmer, Mihkel

2016-01-01

38 first-episode psychosis (FEP) patients and 37 control subjects were recruited for the study of indices of oxidative stress (OxS). The main purpose of the study was to compare the OxS statuses (serum total antioxidant capacity (TAC), total level of peroxides (TPX), oxidative stress index (OSI), and ratio oxidized methionine (Met-SO) to methionine (Met)) between antipsychotic-naïve FEP patients and individuals without a history of psychiatric disorders. Subsequently, the impact of 7-month antipsychotic treatment was evaluated on the OxS status in FEP patients. An attempt was made to assess links between OxS signature and inflammation markers. The oxidative stress indices remained generally unchanged in antipsychotic-naïve FEP patients compared to control subjects. Despite that, there was a significant correlation between the levels of TPX and EGF (endothelial growth factor) in FEP patients. This correlation disappeared after antipsychotic treatment of FEP patients. Moreover, antipsychotic treatment was associated with a significant reduction in OxS indices, including TPX, OSI, and ratio between Met-SO and Met. By contrast, in chronic SCZ patients we established a significant high-grade OxS. In conclusion, the markers of total antioxidative capacity, lipid peroxidation, and protein oxidation revealed no high-grade OxS in FEP patients. Nevertheless, antipsychotic treatment induced a considerable anti-inflammatory effect. OxS levels were also significantly decreased if compared in FEP patients before and after antipsychotic treatment. PMID:27528889

Effect of Grinding at Modified Atmosphere or Vacuum on Browning, Antioxidant Capacities, and Oxidative Enzyme Activities of Apple.

PubMed

Kim, Ah-Na; Lee, Kyo-Yeon; Kim, Hyun-Jin; Chun, Jiyeon; Kerr, William L; Choi, Sung-Gil

2018-01-01

This study evaluated the effects of grinding at atmospheric pressure (control), under vacuum (∼2.67 kPa), or with modified atmosphere (N 2 and CO 2 ) on the browning, antioxidant activity, phenolics, and oxidative enzyme activity of apples as a function of time. The control group was affected most, showing distinct browning and losing most of the antioxidant activity and concentrations of the main phenolic compounds. The modified atmosphere groups retained color, antioxidant activity, and phenolic compounds better than the control group. Least changes were obtained with vacuum grinding, particularly in terms of preventing enzymatic browning and oxidation of antioxidants apples. At 12 h after grinding, vacuum-ground apples retained total phenolic contents 5.32, 1.54, and 1.49 times higher than control, nitrogen gas, and carbon dioxide gas-ground samples, respectively. The oxidative enzyme activity, including that of polyphenol oxidase and peroxidase, decreased in the control and modified atmosphere group, but they were maintained in the samples ground under the vacuum. In this study, we found that grinding with modified atmosphere or vacuum conditions could effectively prevent browning as well as loss of phenolic compounds and antioxidant activity of ground apples. These results can help scientists and engineers build better grinding systems for retaining nutrient and quality factors of ground apples. In addition, these results may be useful to other fruit and vegetable industries that wish to retain fresh-like quality and nutritional value during grinding and storage. © 2017 Institute of Food Technologists®.

Perm1 enhances mitochondrial biogenesis, oxidative capacity, and fatigue resistance in adult skeletal muscle

PubMed Central

Cho, Yoshitake; Hazen, Bethany C.; Gandra, Paulo G.; Ward, Samuel R.; Schenk, Simon; Russell, Aaron P.; Kralli, Anastasia

2016-01-01

Skeletal muscle mitochondrial content and oxidative capacity are important determinants of muscle function and whole-body health. Mitochondrial content and function are enhanced by endurance exercise and impaired in states or diseases where muscle function is compromised, such as myopathies, muscular dystrophies, neuromuscular diseases, and age-related muscle atrophy. Hence, elucidating the mechanisms that control muscle mitochondrial content and oxidative function can provide new insights into states and diseases that affect muscle health. In past studies, we identified Perm1 (PPARGC1- and ESRR-induced regulator, muscle 1) as a gene induced by endurance exercise in skeletal muscle, and regulating mitochondrial oxidative function in cultured myotubes. The capacity of Perm1 to regulate muscle mitochondrial content and function in vivo is not yet known. In this study, we use adeno-associated viral (AAV) vectors to increase Perm1 expression in skeletal muscles of 4-wk-old mice. Compared to control vector, AAV1-Perm1 leads to significant increases in mitochondrial content and oxidative capacity (by 40–80%). Moreover, AAV1-Perm1–transduced muscles show increased capillary density and resistance to fatigue (by 33 and 31%, respectively), without prominent changes in fiber-type composition. These findings suggest that Perm1 selectively regulates mitochondrial biogenesis and oxidative function, and implicate Perm1 in muscle adaptations that also occur in response to endurance exercise.—Cho, Y., Hazen, B. C., Gandra, P. G., Ward, S. R., Schenk, S., Russell, A. P., Kralli, A. Perm1 enhances mitochondrial biogenesis, oxidative capacity, and fatigue resistance in adult skeletal muscle. PMID:26481306

GSTP1 Loss results in accumulation of oxidative DNA base damage and promotes prostate cancer cell survival following exposure to protracted oxidative stress.

PubMed

Mian, Omar Y; Khattab, Mohamed H; Hedayati, Mohammad; Coulter, Jonathan; Abubaker-Sharif, Budri; Schwaninger, Julie M; Veeraswamy, Ravi K; Brooks, James D; Hopkins, Lisa; Shinohara, Debika Biswal; Cornblatt, Brian; Nelson, William G; Yegnasubramanian, Srinivasan; DeWeese, Theodore L

2016-02-01

Epigenetic silencing of glutathione S-transferase π (GSTP1) is a hallmark of transformation from normal prostatic epithelium to adenocarcinoma of the prostate. The functional significance of this loss is incompletely understood. The present study explores the effects of restored GSTP1 expression on glutathione levels, accumulation of oxidative DNA damage, and prostate cancer cell survival following oxidative stress induced by protracted, low dose rate ionizing radiation (LDR). GSTP1 protein expression was stably restored in LNCaP prostate cancer cells. The effect of GSTP1 restoration on protracted LDR-induced oxidative DNA damage was measured by GC-MS quantitation of modified bases. Reduced and oxidized glutathione levels were measured in control and GSTP1 expressing populations. Clonogenic survival studies of GSTP1- transfected LNCaP cells after exposure to protracted LDR were performed. Global gene expression profiling and pathway analysis were performed. GSTP1 expressing cells accumulated less oxidized DNA base damage and exhibited decreased survival compared to control LNCaP-Neo cells following oxidative injury induced by protracted LDR. Restoration of GSTP1 expression resulted in changes in modified glutathione levels that correlated with GSTP1 protein levels in response to protracted LDR-induced oxidative stress. Survival differences were not attributable to depletion of cellular glutathione stores. Gene expression profiling and pathway analysis following GSTP1 restoration suggests this protein plays a key role in regulating prostate cancer cell survival. The ubiquitous epigenetic silencing of GSTP1 in prostate cancer results in enhanced survival and accumulation of potentially promutagenic DNA adducts following exposure of cells to protracted oxidative injury suggesting a protective, anti-neoplastic function of GSTP1. The present work provides mechanistic backing to the tumor suppressor function of GSTP1 and its role in prostate carcinogenesis. © 2015 Wiley Periodicals, Inc.

GSTP1 Loss Results in Accumulation of Oxidative DNA Base Damage and Promotes Prostate Cancer Cell Survival Following Exposure to Protracted Oxidative Stress

PubMed Central

Mian, Omar Y.; Khattab, Mohamed H.; Hedayati, Mohammad; Coulter, Jonathan; Abubaker-Sharif, Budri; Schwaninger, Julie M.; Veeraswamy, Ravi K.; Brooks, James D.; Hopkins, Lisa; Shinohara, Debika Biswal; Cornblatt, Brian; Nelson, William G.; Yegnasubramanian, Srinivasan; DeWeese, Theodore L.

2016-01-01

BACKGROUND Epigenetic silencing of glutathione S-transferase π (GSTP1) is a hallmark of transformation from normal prostatic epithelium to adenocarcinoma of the prostate. The functional significance of this loss is incompletely understood. The present study explores the effects of restored GSTP1 expression on glutathione levels, accumulation of oxidative DNA damage, and prostate cancer cell survival following oxidative stress induced by protracted, low dose rate ionizing radiation (LDR). METHODS GSTP1 protein expression was stably restored in LNCaP prostate cancer cells. The effect of GSTP1 restoration on protracted LDR-induced oxidative DNA damage was measured by GC-MS quantitation of modified bases. Reduced and oxidized glutathione levels were measured in control and GSTP1 expressing populations. Clonogenic survival studies of GSTP1-transfected LNCaP cells after exposure to protracted LDR were performed. Global gene expression profiling and pathway analysis were performed. RESULTS GSTP1 expressing cells accumulated less oxidized DNA base damage and exhibited decreased survival compared to control LNCaP-Neo cells following oxidative injury induced by protracted LDR. Restoration of GSTP1 expression resulted in changes in modified glutathione levels that correlated with GSTP1 protein levels in response to protracted LDR-induced oxidative stress. Survival differences were not attributable to depletion of cellular glutathione stores. Gene expression profiling and pathway analysis following GSTP1 restoration suggests this protein plays a key role in regulating prostate cancer cell survival. CONCLUSIONS The ubiquitous epigenetic silencing of GSTP1 in prostate cancer results in enhanced survival and accumulation of potentially promutagenic DNA adducts following exposure of cells to protracted oxidative injury suggesting a protective, anti-neoplastic function of GSTP1. The present work provides mechanistic backing to the tumor suppressor function of GSTP1 and its role in prostate carcinogenesis. PMID:26447830

Oxidation of glycosaminoglycans by free radicals and reactive oxidative species: A review of investigative methods.

PubMed

Parsons, B J

2015-05-01

Glycosaminoglycans, in particular hyaluronan (HA), and proteoglycans are components of the extracellular matrix (ECM). The ECM plays a key role in the regulation of cellular behaviour and alterations to it can modulate both the development of human diseases as well as controlling normal biochemical processes such as cell signalling and pro-inflammatory responses. For these reasons, in vitro fragmentation studies of glycosaminoglycans by free radicals and oxidative species are seen to be relevant to the understanding of in vivo studies of damage to the ECM. A wide range of investigative techniques have therefore been applied to gain insights into the relative fragmentation effects of several reactive oxidative species with the ultimate goal of determining mechanisms of fragmentation at the molecular level. These methods are reviewed here.

Control of the Pore Texture in Nanoporous Silicon via Chemical Dissolution.

PubMed

Secret, Emilie; Wu, Chia-Chen; Chaix, Arnaud; Galarneau, Anne; Gonzalez, Philippe; Cot, Didier; Sailor, Michael J; Jestin, Jacques; Zanotti, Jean-Marc; Cunin, Frédérique; Coasne, Benoit

2015-07-28

The surface and textural properties of porous silicon (pSi) control many of its physical properties essential to its performance in key applications such as optoelectronics, energy storage, luminescence, sensing, and drug delivery. Here, we combine experimental and theoretical tools to demonstrate that the surface roughness at the nanometer scale of pSi can be tuned in a controlled fashion using partial thermal oxidation followed by removal of the resulting silicon oxide layer with hydrofluoric acid (HF) solution. Such a process is shown to smooth the pSi surface by means of nitrogen adsorption, electron microscopy, and small-angle X-ray and neutron scattering. Statistical mechanics Monte Carlo simulations, which are consistent with the experimental data, support the interpretation that the pore surface is initially rough and that the oxidation/oxide removal procedure diminishes the surface roughness while increasing the pore diameter. As a specific example considered in this work, the initial roughness ξ ∼ 3.2 nm of pSi pores having a diameter of 7.6 nm can be decreased to 1.0 nm following the simple procedure above. This study allows envisioning the design of pSi samples with optimal surface properties toward a specific process.

Formation of Plant Sterol Oxidation Products in Foods during Baking and Cooking Using Margarine without and with Added Plant Sterol Esters.

PubMed

Lin, Yuguang; Knol, Diny; Menéndez-Carreño, María; Blom, Wendy A M; Matthee, Joep; Janssen, Hans-Gerd; Trautwein, Elke A

2016-01-27

Plant sterols (PS) in foods are subject to thermal oxidation to form PS oxidation products (POP). This study measured POP contents of 19 foods prepared by typical household baking and cooking methods using margarines without (control) and with 7.5% added PS (as 12.5% PS-esters, PS-margarine). Median POP contents per portion size of cooked foods were 0.57 mg (range 0.05-1.11 mg) with control margarine versus 1.42 mg (range 0.08-20.5 mg) with PS-margarine. The oxidation rate of PS (ORP) was 0.50% (median) with the PS-margarine and 3.66% with the control margarine. Using the PS-margarine, microwave-cooked codfish had the lowest POP content, with 0.08 mg per portion, while shallow-fried potatoes had the highest POP content, 20.5 mg per portion. Median POP contents in cookies, muffins, banana bread, and sponge cake baked with the control or PS-margarine were 0.12 mg (range 0.11-0.21 mg) and 0.24 mg (range 0.19-0.60 mg) per portion, with a corresponding ORP of 1.38% and 0.06%, respectively. POP contents in all the cooked and baked foods did not exceed 20.5 mg per typical portion size. A wide variation in the distribution of individual POP among different foods existed, with 7-keto-PS and 5,6-epoxy-PS being the major oxidation products.

Mechanisms of MDMA (Ecstasy)-Induced Oxidative Stress, Mitochondrial Dysfunction, and Organ Damage

PubMed Central

Song, Byoung-Joon; Moon, Kwan-Hoon; Upreti, Vijay V.; Eddington, Natalie D.; Lee, Insong J.

2010-01-01

Despite numerous reports about the acute and sub-chronic toxicities caused by MDMA (3,4-methylenedioxymethamphetamine, ecstasy), the underlying mechanism of organ damage is poorly understood. The aim of this review is to present an update of the mechanistic studies on MDMA-mediated organ damage partly caused by increased oxidative/nitrosative stress. Because of the extensive reviews on MDMA-mediated oxidative stress and tissue damage, we specifically focus on the mechanisms and consequences of oxidative-modifications of mitochondrial proteins, leading to mitochondrial dysfunction. We briefly describe a method to systematically identify oxidatively-modified mitochondrial proteins in control and MDMA-exposed rats by using biotin-N-maleimide (biotin-NM) as a sensitive probe for oxidized proteins. We also describe various applications and advantages of this Cys-targeted proteomics method and alternative approaches to overcome potential limitations of this method in studying oxidized proteins from MDMA-exposed tissues. Finally we discuss the mechanism of synergistic drug-interaction between MDMA and other abused substances including alcohol (ethanol) as well as application of this redox-based proteomics method in translational studies for developing effective preventive and therapeutic agents against MDMA-induced organ damage. PMID:20420575

Meat processing and colon carcinogenesis: cooked, nitrite-treated, and oxidized high-heme cured meat promotes mucin-depleted foci in rats.

PubMed

Santarelli, Raphaëlle L; Vendeuvre, Jean-Luc; Naud, Nathalie; Taché, Sylviane; Guéraud, Françoise; Viau, Michelle; Genot, Claude; Corpet, Denis E; Pierre, Fabrice H F

2010-07-01

Processed meat intake is associated with colorectal cancer risk, but no experimental study supports the epidemiologic evidence. To study the effect of meat processing on carcinogenesis promotion, we first did a 14-day study with 16 models of cured meat. Studied factors, in a 2 x 2 x 2 x 2 design, were muscle color (a proxy for heme level), processing temperature, added nitrite, and packaging. Fischer 344 rats were fed these 16 diets, and we evaluated fecal and urinary fat oxidation and cytotoxicity, three biomarkers of heme-induced carcinogenesis promotion. A principal component analysis allowed for selection of four cured meats for inclusion into a promotion study. These selected diets were given for 100 days to rats pretreated with 1,2-dimethylhydrazine. Colons were scored for preneoplastic lesions: aberrant crypt foci (ACF) and mucin-depleted foci (MDF). Cured meat diets significantly increased the number of ACF/colon compared with a no-meat control diet (P = 0.002). Only the cooked nitrite-treated and oxidized high-heme meat significantly increased the fecal level of apparent total N-nitroso compounds (ATNC) and the number of MDF per colon compared with the no-meat control diet (P < 0.05). This nitrite-treated and oxidized cured meat specifically increased the MDF number compared with similar nonnitrite-treated meat (P = 0.03) and with similar nonoxidized meat (P = 0.004). Thus, a model cured meat, similar to ham stored aerobically, increased the number of preneoplastic lesions, which suggests colon carcinogenesis promotion. Nitrite treatment and oxidation increased this promoting effect, which was linked with increased fecal ATNC level. This study could lead to process modifications to make nonpromoting processed meat. 2010 AACR.

Oxidation of Ca-α-SiAlON Powders Prepared by Combustion Synthesis

PubMed Central

Li, Jinfu; Li, Zhongmin; Wang, Enhui; Wang, Zhanjun; Yin, Xiaowei; Zhang, Zuotai

2015-01-01

The oxidation of Ca-α-SiAlON synthesized by the combustion synthesis (CS) method with different additives was investigated in air atmosphere using thermogravimetric (TG) analysis in a temperature range from 1453 K to 1653 K. The experimental results indicated that oxidation was controlled by mixed chemical and diffusion steps. The oxidation products by XRD analysis were composed of SiO2 and CaAl2Si2O8 at low oxidation temperature, whereas the SiO2-Al2O3-CaO ternary glassy phase was formed at elevated temperature. The deviation of oxidation resistance from each sample may be due to the morphological difference brought about by different additive additions. This study reveals the effects of additives on the oxidation resistance of synthesized Ca-α-SiAlON powders. PMID:28793657

Formation of porous silicon oxide from substrate-bound silicon rich silicon oxide layers by continuous-wave laser irradiation

NASA Astrophysics Data System (ADS)

Wang, Nan; Fricke-Begemann, Th.; Peretzki, P.; Ihlemann, J.; Seibt, M.

2018-03-01

Silicon nanocrystals embedded in silicon oxide that show room temperature photoluminescence (PL) have great potential in silicon light emission applications. Nanocrystalline silicon particle formation by laser irradiation has the unique advantage of spatially controlled heating, which is compatible with modern silicon micro-fabrication technology. In this paper, we employ continuous wave laser irradiation to decompose substrate-bound silicon-rich silicon oxide films into crystalline silicon particles and silicon dioxide. The resulting microstructure is studied using transmission electron microscopy techniques with considerable emphasis on the formation and properties of laser damaged regions which typically quench room temperature PL from the nanoparticles. It is shown that such regions consist of an amorphous matrix with a composition similar to silicon dioxide which contains some nanometric silicon particles in addition to pores. A mechanism referred to as "selective silicon ablation" is proposed which consistently explains the experimental observations. Implications for the damage-free laser decomposition of silicon-rich silicon oxides and also for controlled production of porous silicon dioxide films are discussed.

Electronic-Reconstruction-Enhanced Tunneling Conductance at Terrace Edges of Ultrathin Oxide Films.

PubMed

Wang, Lingfei; Kim, Rokyeon; Kim, Yoonkoo; Kim, Choong H; Hwang, Sangwoon; Cho, Myung Rae; Shin, Yeong Jae; Das, Saikat; Kim, Jeong Rae; Kalinin, Sergei V; Kim, Miyoung; Yang, Sang Mo; Noh, Tae Won

2017-11-01

Quantum mechanical tunneling of electrons across ultrathin insulating oxide barriers has been studied extensively for decades due to its great potential in electronic-device applications. In the few-nanometers-thick epitaxial oxide films, atomic-scale structural imperfections, such as the ubiquitously existed one-unit-cell-high terrace edges, can dramatically affect the tunneling probability and device performance. However, the underlying physics has not been investigated adequately. Here, taking ultrathin BaTiO 3 films as a model system, an intrinsic tunneling-conductance enhancement is reported near the terrace edges. Scanning-probe-microscopy results demonstrate the existence of highly conductive regions (tens of nanometers wide) near the terrace edges. First-principles calculations suggest that the terrace-edge geometry can trigger an electronic reconstruction, which reduces the effective tunneling barrier width locally. Furthermore, such tunneling-conductance enhancement can be discovered in other transition metal oxides and controlled by surface-termination engineering. The controllable electronic reconstruction can facilitate the implementation of oxide electronic devices and discovery of exotic low-dimensional quantum phases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

40 CFR 52.2033 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 5 2014-07-01 2014-07-01 false Control strategy: Sulfur oxides. 52.2033 Section 52.2033 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... strategy: Sulfur oxides. (a) [Reserved] (b) EPA approves the attainment demonstration State Implementation...

Improvements of electronic and optical characteristics of n-GaN-based structures by photoelectrochemical oxidation in glycol solution

NASA Astrophysics Data System (ADS)

Shiozaki, Nanako; Hashizume, Tamotsu

2009-03-01

Surface control of n-GaN was performed by applying a photoelectrochemical oxidation method in a glycol solution to improve the optical and electronic characteristics. The fundamental properties of the oxidation were investigated. The oxidation, chemical composition, and bonding states were analyzed by x-ray photoelectron spectroscopy and micro-Auger electron spectroscopy, in which confirmed the formation of gallium oxide on the surface. The oxide formation rate was about 8 nm/min under UV illumination of 4 mW/cm2. After establishing the basic properties for control of n-GaN oxidation, the surface control technique was applied to achieve low-damage etching, enhancement of the photoluminescence intensity, and selective passivation of the air-exposed sidewalls in an AlGaN/GaN high electron mobility transistor wire structure. The capacitance-voltage measurement revealed the minimum interface-state density between GaN and anodic oxide to be about 5×1011 cm-2 eV-1, which is rather low value for compound semiconductors.

A new aerobic chemolithoautotrophic arsenic oxidizing microorganism isolated from a high Andean watershed.

PubMed

Anguita, Javiera M; Rojas, Claudia; Pastén, Pablo A; Vargas, Ignacio T

2018-02-01

Biological arsenic oxidation has been suggested as a key biogeochemical process that controls the mobilization and fate of this metalloid in aqueous environments. To the best of our knowledge, only four aerobic chemolithoautotrophic arsenite-oxidizing (CAO) bacteria have been shown to grow via direct arsenic oxidation and to have the essential genes for chemolithoautotrophic arsenite oxidation. In this study, a new CAO bacterium was isolated from a high Andean watershed evidencing natural dissolved arsenic attenuation. The bacterial isolate, designated TS-1, is closely related to the Ancylobacter genus, in the Alphaproteobacteria class. Results showed that TS-1 has genes for arsenite oxidation and carbon fixation. The dependence of bacterial growth from arsenite oxidation was demonstrated. In addition, a mathematical model was suggested and the kinetic parameters were obtained by simultaneously fitting the biomass growth, arsenite depletion curves, and arsenate production. This research increases the knowledge of chemolithoautotrophic arsenic oxidizing microorganisms and its potential role as a driver for natural arsenic attenuation.

Titanium-nitride-oxide-coated coronary stents: insights from the available evidence.

PubMed

Karjalainen, Pasi P; Nammas, Wail

2017-06-01

Coating of stent surface with a biocompatible material is suggested to improve stent safety profile. A proprietary process was developed to coat titanium-nitride-oxide on the stent surface, based on plasma technology that uses the nano-synthesis of gas and metal. Preclinical in vitro and in vivo investigation confirmed blood compatibility of titanium (nitride-) oxide films. Titanium-nitride-oxide-coated stents demonstrated a better angiographic outcome, compared with bare-metal stents at mid-term follow-up; however, they failed to achieve non-inferiority for angiographic outcome versus second-generation drug-eluting stents. Observational studies showed adequate clinical outcome at mid-term follow-up. Non-randomized studies showed an outcome of titanium-nitride-oxide-coated stents comparable to - or better than - first-generation drug-eluting stents at long-term follow-up. Two randomized controlled trials demonstrated comparable efficacy outcome, and a better safety outcome of titanium-nitride-oxide-coated stents versus drug-eluting stents at long-term follow-up. Evaluation by optical coherence tomography at mid-term follow-up revealed better neointimal strut coverage associated with titanium-nitride-oxide-coated stents versus drug-eluting stents; yet, neointimal hyperplasia thickness was greater. Key messages Stents coated with titanium-nitride-oxide demonstrated biocompatibility in preclinical studies: they inhibit platelet and fibrin deposition, and reduce neointimal growth. In observational and non-randomized studies, titanium-nitride-oxide-coated stents were associated with adequate safety and efficacy outcome. In randomized trials of patients with acute coronary syndrome, titanium-nitride-oxide-coated stents were associated with a better safety outcome, compared with drug-eluting stents; efficacy outcome was comparable.

Interrogation of bimetallic particle oxidation in three dimensions at the nanoscale

DOE PAGES

Han, Lili; Meng, Qingping; Wang, Deli; ...

2016-12-08

An understanding of bimetallic alloy oxidation is key to the design of hollow-structured binary oxides and the optimization of their catalytic performance. However, one roadblock encountered in studying these binary oxide systems is the difficulty in describing the heterogeneities that occur in both structure and chemistry as a function of reaction coordinate. This is due to the complexity of the three-dimensional mosaic patterns that occur in these heterogeneous binary systems. By combining real-time imaging and chemical-sensitive electron tomography, we show that it is possible to characterize these systems with simultaneous nanoscale and chemical detail. We find that there is oxidation-inducedmore » chemical segregation occurring on both external and internal surfaces. Additionally, there is another layer of complexity that occurs during the oxidation, namely that the morphology of the initial oxide surface can change the oxidation modality. As a result, this work characterizes the pathways that can control the morphology in binary oxide materials.« less

Elevated Levels of Urinary Markers of Oxidative DNA and RNA Damage in Type 2 Diabetes with Complications.

PubMed

Liu, Xinle; Gan, Wei; Zou, Yuangao; Yang, Bin; Su, Zhenzhen; Deng, Jin; Wang, Lanlan; Cai, Jianping

2016-01-01

The mechanisms underlying progression of type 2 diabetes are complex and varied. Recent studies indicated that oxidative stress provided a new sight. To further assess the relationship between nucleic acid oxidation and complications in patients with type 2 diabetes and explore its possible molecular mechanisms, we studied 1316 subjects, including 633 type 2 diabetes patients and 683 age- and sex-matched healthy controls. Urinary levels of DNA oxidation marker 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) and RNA oxidation marker 8-oxo-7,8-dihydroguanosine (8-oxoGuo) were measured by ultraperformance liquid chromatography and mass spectrometry (UPLC-MS/MS). Serum glucose, HbA1c, total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides (TG) were also determined. The results showed significantly elevated levels of both the urinary 8-oxodGuo and 8-oxoGuo in diabetes patients with/without complications compared with age-matched healthy control subjects (p = 0.02 and p < 0.001, resp.). Patients with complications, especially macrovascular complications, exhibited higher levels of 8-oxoGuo than those without complications, while there was no difference in the concentrations of serum glucose and lipids. The finding indicates the role for oxidative damage to DNA and RNA, as a molecular mechanism contributing to the progression of type 2 diabetes. Elevated levels of 8-oxoGuo may be a risk factor for type 2 diabetes complications, especially in diabetic macrovascular complications.

Strain control of oxygen vacancies in epitaxial strontium cobaltite films

DOE PAGES

Jeen, Hyoung Jeen; Choi, Woo Seok; Reboredo, Fernando A.; ...

2016-01-25

In this study, the ability to manipulate oxygen anion defects rather than metal cations in complex oxides can facilitate creating new functionalities critical for emerging energy and device technologies. However, the difficulty in activating oxygen at reduced temperatures hinders the deliberate control of important defects, oxygen vacancies. Here, strontium cobaltite (SrCoO x) is used to demonstrate that epitaxial strain is a powerful tool for manipulating the oxygen vacancy concentration even under highly oxidizing environments and at annealing temperatures as low as 300 °C. By applying a small biaxial tensile strain (2%), the oxygen activation energy barrier decreases by ≈30%, resultingmore » in a tunable oxygen deficient steady-state under conditions that would normally fully oxidize unstrained cobaltite. These strain-induced changes in oxygen stoichiometry drive the cobaltite from a ferromagnetic metal towards an antiferromagnetic insulator. The ability to decouple the oxygen vacancy concentration from its typical dependence on the operational environment is useful for effectively designing oxides materials with a specific oxygen stoichiometry.« less

A crucial role for ethanol-induced oxidative stress in controlling lineage commitment of mesenchymal stromal cells through inhibition of wnt/beta-catenin signaling

USDA-ARS?s Scientific Manuscript database

Female skeletal responses to ethanol may vary depending on the physiologic status (viz. cycling, pregnancy, lactation). Nonetheless, ethanol-induced oxidative stress appears to be the key event leading to skeletal toxicity. In the current study, we chronically infused EtOH-containing liquid diets ...

A template-free solvent-mediated synthesis of high surface area boron nitride nanosheets for aerobic oxidative desulfurization

DOE PAGES

Wu, Peiwen; Zhu, Wenshuai; Chao, Yanhong; ...

2015-10-16

Hexagonal boron nitride nanosheets (h-BNNs) with rather high specific surface area (SSA) are important two-dimensional layer-structured materials. Here in this study, a solvent-mediated synthesis of h-BNNs revealed a template-free lattice plane control strategy that induced high SSA nanoporous structured h-BNNs with outstanding aerobic oxidative desulfurization performance.

Plant-Based Nutraceutical Increases Plasma Catalase Activity in Healthy Participants: A Small Double-Blind, Randomized, Placebo-Controlled, Proof of Concept Trial.

PubMed

Sweazea, Karen L; Johnston, Carol S; Knurick, Jessica; Bliss, Courtney D

2017-03-04

Oxidative stress resulting from dietary, lifestyle and environmental factors is strongly associated with tissue damage and aging. It occurs when there is either an overproduction of reactive oxygen species (i.e., oxidants) or decreased bioavailability of antioxidants that can scavenge them. The objective of this 12-week double-blind placebo-controlled study was to assess the efficacy of a nutraceutical at augmenting antioxidant status. Healthy adults (25-45 y) were randomized to either a treatment group (Product B, n = 23) or a placebo group (control, n = 20). No significant effect of Product B was observed for anthropometric variables or markers of glucose and lipid regulation. Biomarkers of oxidative stress were likewise not altered following the 12-week intervention. Plasma catalase concentrations were significantly elevated following 12 weeks of Product B as compared to the control group (+6.1 vs. -10.3 nmol/min/mL, p = 0.038), whereas other measures of antioxidant capacity were not significantly different between the groups. Product B effectively augmented concentrations of the anti-aging antioxidant catalase in healthy adults.

Genotoxicity and oxidative stress in chromium-exposed tannery workers in North India.

PubMed

Ambreen, Khushboo; Khan, Faizan Haider; Bhadauria, Smrati; Kumar, Sudhir

2014-06-01

Trivalent chromium (Cr) is an environmental contaminant, which is extensively used in tanning industries throughout the world and causes various forms of health hazards in tannery workers. Therefore, a cross-sectional study design was used to evaluate the DNA damage and oxidative stress condition in tannery workers exposed to Cr in North India. The study population comprised 100 male tanners in the exposed group and 100 healthy males (no history of Cr exposure) in the comparable control group. Baseline characteristics including age, smoking, alcohol consumption habits and duration of exposure were recorded via interviewing the subjects. Blood Cr level (measured by atomic absorption spectrophotometry), DNA damage (measured by comet assay) and oxidative stress parameters (malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD)) were estimated in both the groups. As a result of statistical analysis, exposed group showed significantly higher level of Cr (p < 0.0001), DNA damage (p < 0.0001), MDA (p < 0.0001), SOD (p < 0.05) and lower level of GSH (p < 0.001) when compared with controls. Smoking, alcohol consumption habits and age had no significant effect (p > 0.05) on DNA damage and oxidative stress parameters in both the groups. In simple and multiple correlation analysis, DNA damage and oxidative stress parameters showed significant correlation with Cr level and duration of exposure in exposed group. The findings of the present study revealed that chronic occupational exposure to trivalent Cr may cause DNA damage and oxidative stress in tannery workers. © The Author(s) 2012.

Pulmonary function and oxidative stress in workers exposed to styrene in plastic factory: occupational hazards in styrene-exposed plastic factory workers.

PubMed

Sati, Prakash Chandra; Khaliq, Farah; Vaney, Neelam; Ahmed, Tanzeel; Tripathi, Ashok K; Banerjee, Basu Dev

2011-11-01

Styrene is a volatile organic compound used in factories for synthesis of plastic products. The pneumotoxicity of styrene in experimental animals is known. The aim of the present study was to study the effect of styrene on lung function and oxidative stress in occupationally exposed workers in plastic factory. Thirty-four male workers, between 18 and 40 years of age, exposed to styrene for atleast 8 hours a day for more than a year were studied, while 30 age- and sex-matched healthy subjects not exposed to styrene served as controls. Assessment of lung functions showed a statistically significant reduction (p < 0.05) in most of the lung volumes, capacities (FVC, FEV(1), VC, ERV, IRV, and IC) and flow rates (PEFR, MEF(75%), and MVV) in the study group (workers) as compared to controls. Malondialdehyde (MDA) was observed to be significantly high (p < 0.05) while ferric-reducing ability of plasma (FRAP) was significantly low (p < 0.05) in styrene-exposed subjects. Reduced glutathione (GSH) level was significantly depleted in exposed subjects as compared to control group. The mean value of serum cytochrome c in styrene-exposed subjects was found to be 1.1 ng/ml (0.89-1.89) while in control its levels were under detection limit (0.05 ng/ml). It shows that styrene inhalation by workers leads to increased level of oxidative stress, which is supposed to be the cause of lung damage.

Plasma Homocysteine Is Associated with Increased Oxidative Stress and Antioxidant Enzyme Activity in Welders

PubMed Central

Liu, Hung-Hsin; Shih, Tung-Sheng; Huang, Hsin-Ru; Huang, Shih-Chien; Lee, Lien-Hsiung; Huang, Yi-Chia

2013-01-01

The purpose of this study was to examine the association of vitamin B6 status and plasma homocysteine with oxidative stress and antioxidant capacities in welders. Workers were divided into either the welding exposure group (n = 57) or the nonexposure controls (n = 42) based on whether they were employed as welders. There were no significant differences in vitamin B6 status and plasma homocysteine concentration between the welding exposure group and the nonexposure controls. The welding exposure group had significantly higher levels of oxidized low-density lipoprotein cholesterol and lower erythrocyte glutathione concentration and superoxide dismutase (SOD) activities when compared to nonexposure controls. Plasma pyridoxal 5′-phosphate concentration did not correlate with oxidative stress indicators or antioxidant capacities in either group. However, plasma homocysteine significantly correlated with total antioxidant capacity (TAC) (partial r s = −0.34, P < 0.05) and erythrocyte SOD activities (partial r s = 0.29, P < 0.05) after adjusting for potential confounders in the welding exposure group. In the welding exposure group, adequate vitamin B6 status was not associated with oxidative stress or antioxidant capacities. However, elevated plasma homocysteine seemed to be a major contributing factor to antioxidant capacities (TAC and erythrocyte SOD activities) in welders. PMID:24106453