Hydroquinone, a benzene metabolite, induces Hog1-dependent stress response signaling and causes aneuploidy in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Shiga, Takeki; Suzuki, Hiroyuki; Yamamoto, Hiroaki; Yamamoto, Kazuo; Yamamoto, Ayumi

2010-01-01

Previously, we have shown that phenyl hydroquinone, a hepatic metabolite of the Ames test-negative carcinogen o-phenylphenol, efficiently induced aneuploidy in Saccharomyces cerevisiae by arresting the cell cycle at the G2/M transition as a result of the activation of the Hog1 (p38 MAPK homolog)-Swe1 (Wee1 homolog) pathway. In this experiment, we examined the aneuploidy forming effects of hydroquinone, a benzene metabolite, since both phenyl hydroquinone and hydroquinone are Ames-test negative carcinogens and share similar molecular structures. As was seen in phenyl hydroquinone, hydroquinone induced aneuploidy in yeast by delaying the cell cycle at the G2/M transition. Deficiencies in SWE1 and HOG1 abolished the hydroquinone-induced delay at the G2/M transition and aneuploidy formation. Furthermore, Hog1 was phosphorylated by hydroquinone, which may stabilize Swe1. These data indicate that the hydroquinone-induced G2/M transition checkpoint, which is activated by the Hog1-Swe1 pathway, plays a role in the formation of aneuploidy. (author)

Development of technology for the alkylation of hydroquinone with aliphatic alcohols

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V. M. Bolotov

2017-01-01

Full Text Available The paper presents the results of research of technology of alkylation of hydroquinone, propyl, isopropyl, isobutyl and tert-butyl alcohols in the presence of concentrated phosphoric acid. The temperature of the alkylation reaction was maintained between 70–72 °С. On the basis of literature data and preliminary investigations the reaction was performed for 4 hours. Upon completion of the reaction, we removed the unreacted hydroquinone, aliphatic alcohol and phosphoric acid are added to a solution of distilled water (solvent corresponding connections and sodium bicarbonate to slightly acidic (pH 5–6. For separation from the reaction medium of alkylhydroquinones in the reaction mixture was added benzene in which the original hydroquinone dissolves much less. Concentration of the benzene extract alkylhydroquinones conducted by Stripping the solvent under vacuum at temperatures above 70 °С in air atmosphere. Higher temperature vacuum distillation AIDS in the oxidation of alkylhydroquinones to alkylphenones. Precipitated after crystallization, alkylhydroquinones were dried under vacuum in a drying pistol at 56 °С. Dried products were identified by defining the melting temperature, the study of spectral characteristics and qualitative reactions with FeCl3. We also studied the solubility of alkylhydroquinones in various solvents, which showed low solubility of alkylhydroquinones in water, benzene, toluene and higher solubility in propyl and isopropyl alcohols and in acetone. Analysis of the results shows that the obtained alkylhydroquinones are not chemically pure compounds, and contain in their composition of admixture source of hydroquinone. Qualitative reactions of solutions of alkylhydroquinones with FeCl3 solution differ from the corresponding reaction of a solution of hydroquinone. The results of investigations of electronic absorption spectra of alkylhydroquinones and source of hydroquinone in isopropyl alcohol solution did not

Kinetic mechanism and nucleotide specificity of NADH peroxidase

International Nuclear Information System (INIS)

Stoll, V.S.; Blanchard, J.S.

1988-01-01

NADH peroxidase is a flavoprotein isolated from Streptococcus faecalis which catalyzes the pyridine nucleotide-dependent reduction of hydrogen peroxide to water. Initial velocity, product, and dead-end inhibition studies have been performed at pH 7.5 and support a ping-pong kinetic mechanism. In the absence of hydrogen peroxide, both transhydrogenation between NADH and thioNAD, and isotope exchange between [ 14 C]NADH and NAD, have been demonstrated, although in both these experiments, the maximal velocity of nucleotide exchange was less than 1.5% the maximal velocity of the peroxidatic reaction. We propose that NADH binds tightly to both oxidized and two-electron reduced enzyme. NADH oxidation proceeds stereospecifically with the transfer of the 4S hydrogen to enzyme, and then, via exchange, to water. No primary tritium kinetic isotope effect was observed, and no statistically significant primary deuterium kinetic isotope effects on V/K were determined, although primary deuterium kinetic isotope effects on V were observed in the presence and absence of sodium acetate. NADH peroxidase thus shares with other flavoprotein reductases striking kinetic, spectroscopic, and stereochemical similarities. On this basis, we propose a chemical mechanism for the peroxide cleaving reaction catalyzed by NADH peroxidase which involves the obligate formation of a flavinperoxide, and peroxo bond cleavage by nucleophilic attack by enzymatic dithiols

Selection of the Mutants with High Hydroquinone Degradation Ability of Serratia Marcesscen by Plasma Mutation

International Nuclear Information System (INIS)

Yao Risheng; You Qidong; He Weijing; Zhu Huixia

2009-01-01

In this study, an efficient way by plasma induced mutation was applied to improve the hydroquinone degradation capacity of Serratia marcescens AB 90027 (SM27). The results showed that combined with the selection of hydroquinone tolerance, the mutant with high hydroquinone degradation ability induced by plasma could be achieved. The best dose for plasma mutation was 15 s, which showed a 47.0% higher positive mutation ratio. Besides, the aimed mutant was markedly different from the parent strain (SM27) in colonial traits while cultivated on Kings media. Finally, the hydroquinone degradation ratio reached 70.5% using the induced mutant strain with 1500 mg/L hydroquinone (HQ) after 15 days of cultivation as the selective conditions; however, it was only 46.7% for SM27. The improvement of the degradation capacity by the induced mutant with a high concentration of HQ selection was attributed to its faster growth and higher hydroquinone tolerance compared with that of the parent strain.

Vigna radiata as a New Source for Biotransformation of Hydroquinone to Arbutin

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Zahra Tofighi, Mohsen Amini, Mahzad Shirzadi, Hamideh Mirhabibi, Negar Ghazi Saeedi, Narguess Yassa

2016-06-01

Full Text Available Background: The suspension culture of Vigna radiata was selected for biotransformation of hydroquinone to its β-D-glucoside form (arbutin as an important therapeutic and cosmetic compound. Methods: The biotransformation efficiency of a Vigna radiata cell culture in addition to different concentrations of hydroquinone (6-20 mg/100 ml was investigated after 24 hours in comparison to an Echinacea purpurea cell culture and attempts were made to increase the efficacy of the process by adding elicitors. Results: Arbutin was accumulated in cells and found in the media only in insignificant amounts. The arbutin content of the biomass extracts of V. radiata and E. purpurea was different, ranging from 0.78 to 1.89% and 2.00 to 3.55% of dry weight, respectively. V. radiata demonstrated a bioconversion efficiency of 55.82% after adding 8 mg/100 ml precursor, which was comparable with result of 69.53% for E. purpurea cells after adding 10 mg/100 ml hydroquinone (P>0.05. In both cultures, adding hydroquinone in two portions with a 24-hour interval increased the biotransformation efficiency. Different concentrations of methyl jasmonate (25, 50, and 100 µM and chitosan (50 and 100 µg/ml as elicitors increased the bio-efficiency percentage of the V. radiata culture in comparison with the flask containing only hydroquinone. Conclusion: This is the first report of the biotransformation possibility of V. radiata cultures. It was observed the bioconversion capacity increased by adding hydroquinone in two portions, which was comparable to adding an elicitor.

Stabilized NADH as a Countermeasure for Jet Lag

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Kay, Gary G.; Viirre, Erik; Clark, Jonathan

2001-01-01

Current remedies for jet lag (phototherapy, melatonin, stimulant, and sedative medications) are limited in efficacy and practicality. The efficacy of a stabilized, sublingual form of reduced nicotin amide adenine dinucleotide (NADH, ENADAlert, Menuco Corp.) as a countermeasure for jet lag was examined. Because NADH increases cellular production of ATP and facilitates dopamine synthesis, it may counteract the effects of jet lag on cognitive functioning and sleepiness. Thirty-five healthy, employed subjects participated in this double-blind, placebo-controlled study. Training and baseline testing were conducted on the West Coast before subjects flew overnight to the East Coast, where they would experience a 3-hour time difference. Upon arrival, individuals were randomly assigned to receive either 20 mg of sublingual stabilized ADH (n=18) or identical placebo tablets (n=17). All participants completed computer-administered tests (including CogScreen7) to assess changes in cognitive functioning, mood, and sleepiness in the morning and afternoon. Jet lag resulted in increased sleepiness for over half the participants and deterioration of cognitive functioning for approximately one third. The morning following the flight, subjects experienced lapses of attention in addition to disruptions in working memory, divided attention, and visual perceptual speed. Individuals who received NADH performed significantly better on 5 of 8 cognitive and psychomotor test measures (P less than or equal to 0.5) and showed a trend for better performance on the other three measures (P less than or equal to .l0). Subjects also reported less sleepiness compared with those who received placebo. No adverse effects were observed with NADH treatment. Stabilized NADH significantly reduced jet lag-induced disruptions of cognitive functioning, was easily administered, and was found to have no adverse side effects.

Using Poly-L-Histidine Modified Glassy Carbon Electrode to Trace Hydroquinone in the Sewage Water

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Bin Wang

2014-01-01

Full Text Available A sensitive voltammetric method for trace measurements of hydroquinone in the sewage water is described. The poly-L-histidine is prepared to modify the glassy carbon electrode in order to improve the electrochemical catalysis of interesting substances such as hydroquinone. The influence of the base solution, pH value, and scanning speed on the tracing of hydroquinone is discussed, and the experimental procedures and conditions are optimized. The laboratory results show that it is possible to construct a linear calibration curve between the peak current of hydroquinone on modified electrode and its concentration at the level of 0.00001 mol/L. The potential limitation of the method is suggested by a linear peaking shift model as well. The method was successfully applied to the determination of hydroquinone in the actual sample of industrial waste water.

Simultaneous determination of hydroquinone and catechol at gold nanoparticles mesoporous silica modified carbon paste electrode

Energy Technology Data Exchange (ETDEWEB)

Tashkhourian, J., E-mail: tashkhourian@susc.ac.ir [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71456 (Iran, Islamic Republic of); Daneshi, M.; Nami-Ana, F. [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71456 (Iran, Islamic Republic of); Behbahani, M.; Bagheri, A. [Department of Chemistry, Shahid Beheshti University, G.C., Evin, Tehran (Iran, Islamic Republic of)

2016-11-15

Highlights: • An electrochemical sensor based on gold nanoparticles mesoporous silica modified carbon paste electrode was developed. • The electrode provides an accessible surface for simultaneous determination of hydroquinone and catechol. • Hydroquinone and catechol are highly toxic to both environment and human even at very low concentrations. - Abstract: A new electrochemical sensor based on gold nanoparticles mesoporous silica modified carbon paste electrode (AuNPs-MPS) was developed for simultaneous determination of hydroquinone and catechol. Morphology and structure of the AuNPs-MPS were characterized by transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The electrochemical behavior of hydroquinone and catechol were investigated using square wave voltammetry and the results indicate that the electrochemical responses are improved significantly at the modified electrode. The observed oxidative peaks separation of about 120 mV made possible the simultaneous determination of hydroquinone and catechol in their binary-mixture. Under the optimized condition, a linear dynamic range of 10.0 μM–1.0 mM range for hydroquinone with the detection limit of 1.2 μM and from 30.0 μM–1.0 mM for catechol with the detection limit of 1.1 μM were obtained. The applicability of the method was demonstrated by the recovery studies of hydroquinone and catechol in spiked tap water samples.

Pulse photolysis of NADH in the presence of cysteine

International Nuclear Information System (INIS)

Scheel, H.E.

1976-01-01

In the UV irradiation of NADH under anaerobic conditions, cysteine, which often acts as a radioprotective substance, has a sensitizing effect. With the aid of pulse photolysis, it was studied which reaction mechanisms in the presence or absence of cysteine are responsible for the damage to NADH in aqueous solution. In the absence of cysteine, the characteristic NADH absorption at 340 nm is reduced immediately after UV quanta have been absorbed by the adenine fraction of the molecules; in the presence of cysteine, a secondary reaction causes additional damage. The spectra of the intermediate products of NADH and cysteine have been recorded for different cysteine concentrations, and the reaction constants have been determined. These values suggest that the sensitizing effect is due to a reaction of NADH with radical anions produced by photolysis. (orig.) [de

Involvement of NADH Oxidase in Competition and Endocarditis Virulence in Streptococcus sanguinis.

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Ge, Xiuchun; Yu, Yang; Zhang, Min; Chen, Lei; Chen, Weihua; Elrami, Fadi; Kong, Fanxiang; Kitten, Todd; Xu, Ping

2016-05-01

Here, we report for the first time that the Streptococcus sanguinis nox gene encoding NADH oxidase is involved in both competition with Streptococcus mutans and virulence for infective endocarditis. An S. sanguinis nox mutant was found to fail to inhibit the growth of Streptococcus mutans under microaerobic conditions. In the presence of oxygen, the recombinant Nox protein of S. sanguinis could reduce oxygen to water and oxidize NADH to NAD(+) The oxidation of NADH to NAD(+) was diminished in the nox mutant. The nox mutant exhibited decreased levels of extracellular H2O2; however, the intracellular level of H2O2 in the mutant was increased. Furthermore, the virulence of the nox mutant was attenuated in a rabbit endocarditis model. The nox mutant also was shown to be more sensitive to blood killing, oxidative and acid stresses, and reduced growth in serum. Thus, NADH oxidase contributes to multiple phenotypes related to competitiveness in the oral cavity and systemic virulence. Copyright © 2016 Ge et al.

NAD+/NADH and skeletal muscle mitochondrial adaptations to exercise

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White, Amanda T.

2012-01-01

The pyridine nucleotides, NAD+ and NADH, are coenzymes that provide oxidoreductive power for the generation of ATP by mitochondria. In skeletal muscle, exercise perturbs the levels of NAD+, NADH, and consequently, the NAD+/NADH ratio, and initial research in this area focused on the contribution of redox control to ATP production. More recently, numerous signaling pathways that are sensitive to perturbations in NAD+(H) have come to the fore, as has an appreciation for the potential importance of compartmentation of NAD+(H) metabolism and its subsequent effects on various signaling pathways. These pathways, which include the sirtuin (SIRT) proteins SIRT1 and SIRT3, the poly(ADP-ribose) polymerase (PARP) proteins PARP1 and PARP2, and COOH-terminal binding protein (CtBP), are of particular interest because they potentially link changes in cellular redox state to both immediate, metabolic-related changes and transcriptional adaptations to exercise. In this review, we discuss what is known, and not known, about the contribution of NAD+(H) metabolism and these aforementioned proteins to mitochondrial adaptations to acute and chronic endurance exercise. PMID:22436696

NADH oxidase activity (NOX) and enlargement of HeLa cells oscillate with two different temperature-compensated period lengths of 22 and 24 minutes corresponding to different NOX forms

Science.gov (United States)

Wang, S.; Pogue, R.; Morre, D. M.; Morre, D. J.

2001-01-01

NOX proteins are cell surface-associated and growth-related hydroquinone (NADH) oxidases with protein disulfide-thiol interchange activity. A defining characteristic of NOX proteins is that the two enzymatic activities alternate to generate a regular period length of about 24 min. HeLa cells exhibit at least two forms of NOX. One is tumor-associated (tNOX) and is inhibited by putative quinone site inhibitors (e.g., capsaicin or the antitumor sulfonylurea, LY181984). Another is constitutive (CNOX) and refractory to inhibition. The periodic alternation of activities and drug sensitivity of the NADH oxidase activity observed with intact HeLa cells was retained in isolated plasma membranes and with the solubilized and partially purified enzyme. At least two activities were present. One had a period length of 24 min and the other had a period length of 22 min. The lengths of both the 22 and the 24 min periods were temperature compensated (approximately the same when measured at 17, 27 or 37 degrees C) whereas the rate of NADH oxidation approximately doubled with each 10 degrees C rise in temperature. The rate of increase in cell area of HeLa cells when measured by video-enhanced light microscopy also exhibited a complex period of oscillations reflective of both 22 and 24 min period lengths. The findings demonstrate the presence of a novel oscillating NOX activity at the surface of cancer cells with a period length of 22 min in addition to the constitutive NOX of non-cancer cells and tissues with a period length of 24 min.

One-electron transfer reactions of the couple NAD./NADH

International Nuclear Information System (INIS)

Grodkowski, J.; Neta, P.; Carlson, B.W.; Miller, L.

1983-01-01

One-electron transfer reactions involving nicotinamide-adenine dinucleotide in its oxidized and reducd forms (NAD./NADH) were studied by pulse radiolysis in aqueous solutions. One-electron oxidation of NADH by various phenoxyl radicals and phenothiazine cation radicals was found to take place with rate constants in the range of 10 5 to 10 8 M -1 s -1 , depending on the redox potential of the oxidizing species. In all cases, NAD. is formed quantitatively with no indication for the existence of the protonated form (NADH + .). The spectrum of NAD., as well as the rates of oxidation of NADH by phenoxyl and by (chlorpromazine) + . were independent of pH between pH 4.5 and 13.5. Reaction of deuterated NADH indicated only a small kinetic isotope effect. All these findings point to an electron transfer mechanism. On the other hand, attempts to observe the reverse electron transfer, i.e., one-electron reduction of NAD. to NADH by radicals such as semiquinones, showed that k was less than 10 4 to 10 5 M -1 s -1 , so that it was unobservable. Consequently, it was not possible to achieve equilibrium conditions which would have permitted the direct measurement of the redox potential for NAD./NADH. One-electron reduction of NAD. appears to be an unlikely process. 1 table

ZnO: Hydroquinone superlattice structures fabricated by atomic/molecular layer deposition

International Nuclear Information System (INIS)

Tynell, Tommi; Karppinen, Maarit

2014-01-01

Here we employ atomic layer deposition in combination with molecular layer deposition to deposit crystalline thin films of ZnO interspersed with single layers of hydroquinone in an effort to create hybrid inorganic–organic superlattice structures. The ratio of the ZnO and hydroquinone deposition cycles is varied between 199:1 and 1:1, and the structure of the resultant thin films is verified with X-ray diffraction and reflectivity techniques. Clear evidence of the formation of a superlattice-type structure is observed in the X-ray reflectivity patterns and the presence of organic bonds in the films corresponding to the structure of hydroquinone is confirmed with Fourier transform infrared spectroscopy measurements. We anticipate that hybrid superlattice structures such as the ones described in this work have the potential to be of great importance for future applications where the precise control of different inorganic and organic layers in hybrid superlattice materials is required. - Highlights: • Inorganic–organic superlattices can be made by atomic/molecular layer deposition. • This is demonstrated here for ZnO and hydroquinone (HQ). • The ratio of the ZnO and HQ layers is varied between 199:1 and 14:1. • The resultant thin films are crystalline

ZnO: Hydroquinone superlattice structures fabricated by atomic/molecular layer deposition

Energy Technology Data Exchange (ETDEWEB)

Tynell, Tommi; Karppinen, Maarit, E-mail: maarit.karppinen@aalto.fi

2014-01-31

Here we employ atomic layer deposition in combination with molecular layer deposition to deposit crystalline thin films of ZnO interspersed with single layers of hydroquinone in an effort to create hybrid inorganic–organic superlattice structures. The ratio of the ZnO and hydroquinone deposition cycles is varied between 199:1 and 1:1, and the structure of the resultant thin films is verified with X-ray diffraction and reflectivity techniques. Clear evidence of the formation of a superlattice-type structure is observed in the X-ray reflectivity patterns and the presence of organic bonds in the films corresponding to the structure of hydroquinone is confirmed with Fourier transform infrared spectroscopy measurements. We anticipate that hybrid superlattice structures such as the ones described in this work have the potential to be of great importance for future applications where the precise control of different inorganic and organic layers in hybrid superlattice materials is required. - Highlights: • Inorganic–organic superlattices can be made by atomic/molecular layer deposition. • This is demonstrated here for ZnO and hydroquinone (HQ). • The ratio of the ZnO and HQ layers is varied between 199:1 and 14:1. • The resultant thin films are crystalline.

Stimulation of NADH-dependent microsomal DNA strand cleavage by rifamycin SV.

Science.gov (United States)

Kukiełka, E; Cederbaum, A I

1995-04-15

Rifamycin SV is an antibiotic anti-bacterial agent used in the treatment of tuberculosis. This drug can autoxidize, especially in the presence of metals, and generate reactive oxygen species. A previous study indicated that rifamycin SV can increase NADH-dependent microsomal production of reactive oxygen species. The current study evaluated the ability of rifamycin SV to interact with iron and increase microsomal production of hydroxyl radical, as detected by conversion of supercoiled plasmid DNA into the relaxed open circular state. The plasmid used was pBluescript II KS(-), and the forms of DNA were separated by agarose-gel electrophoresis. Incubation of rat liver microsomes with plasmid plus NADH plus ferric-ATP caused DNA strand cleavage. The addition of rifamycin SV produced a time- and concentration-dependent increase in DNA-strand cleavage. No stimulation by rifamycin SV occurred in the absence of microsomes, NADH or ferric-ATP. Stimulation occurred with other ferric complexes besides ferric-ATP, e.g. ferric-histidine, ferric-citrate, ferric-EDTA, and ferric-(NH4)2SO4. Rifamycin SV did not significantly increase the high rates of DNA strand cleavage found with NADPH as the microsomal reductant. The stimulation of NADH-dependent microsomal DNA strand cleavage was completely blocked by catalase, superoxide dismutase, GSH and a variety of hydroxyl-radical-scavenging agents, but not by anti-oxidants that prevent microsomal lipid peroxidation. Redox cycling agents, such as menadione and paraquat, in contrast with rifamycin SV, stimulated the NADPH-dependent reaction; menadione and rifamycin SV were superior to paraquat in stimulating the NADH-dependent reaction. These results indicate that rifamycin SV can, in the presence of an iron catalyst, increase microsomal production of reactive oxygen species which can cause DNA-strand cleavage. In contrast with other redox cycling agents, the stimulation by rifamycin SV is more pronounced with NADH than with NADPH as the

Alterations in cerebral metabolism observed in living rodents using fluorescence lifetime microscopy of intrinsic NADH (Conference Presentation)

Science.gov (United States)

Yaseen, Mohammad A.; Sakadžić, Sava; Sutin, Jason; Wu, Weicheng; Fu, Buyin; Boas, David A.

2017-02-01

Monitoring cerebral energy metabolism at a cellular level is essential to improve our understanding of healthy brain function and its pathological alterations. In this study, we resolve specific alterations in cerebral metabolism utilizing minimally-invasive 2-Photon fluorescence lifetime imaging (2P-FLIM) measurements of reduced nicotinamide adenine dinucleotide (NADH) fluorescence, collected in vivo from anesthetized rats and mice. Time-resolved lifetime measurements enables distinction of different components contributing to NADH autofluorescence. These components reportedly represent different enzyme-bound formulations of NADH. Our observations from this study confirm the hypothesis that NADH FLIM can identify specific alterations in cerebral metabolism. Using time-correlated single photon counting (TCSPC) equipment and a custom-built multimodal imaging system, 2-photon fluorescence lifetime imaging (FLIM) was performed in cerebral tissue with high spatial and temporal resolution. Multi-exponential fits for NADH fluorescence lifetimes indicate 4 distinct components, or 'species.' We observed distinct variations in the relative proportions of these components before and after pharmacological-induced impairments to several reactions involved in anaerobic glycolysis and aerobic oxidative metabolism. Classification models developed with experimental data correctly predict the metabolic impairments associated with bicuculline-induced focal seizures in separate experiments. Compared to traditional intensity-based NADH measurements, lifetime imaging of NADH is less susceptible to the adverse effects of overlying blood vessels. Evaluating NADH measurements will ultimately lead to a deeper understanding of cerebral energetics and its pathology-related alterations. Such knowledge will likely aid development of therapeutic strategies for neurodegenerative diseases such as Alzheimer's Disease, Parkinson's disease, and stroke.

Anticancer activity of botanical alkyl hydroquinones attributed to topoisomerase II poisoning

International Nuclear Information System (INIS)

Huang, C.-P.; Fang, W.-H.; Lin, L.-I.; Chiou, Robin Y.; Kan, L.-S.; Chi, N.-H.; Chen, Y.-R.; Lin, T.-Y.; Lin, S.-B.

2008-01-01

Cytotoxic alkyl hydroquinone compounds have been isolated from many plants. We previously isolated 3 structurally similar cytotoxic alkyl hydroquinone compounds from the sap of the lacquer tree Rhus succedanea L. belonging to the sumac family, which have a long history of medicinal use in Asia. Each has an unsaturated alkyl chain attached to the 2-position of a hydroquinone ring. One of these isolates, 10'(Z),13'(E),15'(E)-heptadecatrienylhydroquinone [HQ17(3)], being the most cytotoxic, was chosen for studying the anticancer mechanism of these compounds. We found that HQ17(3) was a topoisomerase (Topo) II poison. It irreversibly inhibited Topo IIα activity through the accumulation of Topo II-DNA cleavable complexes. A cell-based assay showed that HQ17(3) inhibited the growth of leukemia HL-60 cells with an EC 50 of 0.9 μM, inhibited the topoisomerase-II-deficient cells HL-60/MX2 with an EC 50 of 9.6 μM, and exerted no effect on peripheral blood mononuclear cells at concentrations up to 50 μM. These results suggest that Topo II is the cellular drug target. In HL-60 cells, HQ17(3) promptly inhibited DNA synthesis, induced chromosomal breakage, and led to cell death with an EC 50 about one-tenth that of hydroquinone. Pretreatment of the cells with N-acetylcysteine could not attenuate the cytotoxicity and DNA damage induced by HQ17(3). However, N-acetylcysteine did significantly reduce the cytotoxicity of hydroquinone. In F344 rats, intraperitoneal injection of HQ17(3) for 28 days induced no clinical signs of toxicity. These results indicated that HQ17(3) is a potential anticancer agent, and its structural features could be a model for anticancer drug design

Radioactive scanning agents with hydroquinone stabilizer

International Nuclear Information System (INIS)

Whitehouse, H.S.

1982-01-01

Stable compositions useful as technetium 99m-based scintigraphic agents comprise hydroquinone in combination with a pertechnetate reducing agent or dissolved in pertechnetate-99m (sup(99m)TcOsub(4)sup(-)) solution. The compositions are especially useful in combination with a phosphate or phosphonate material which carries the radionuclide to bone, thus providing a skeletal imaging agent

Modulation of Ras signaling alters the toxicity of hydroquinone, a benzene metabolite and component of cigarette smoke

International Nuclear Information System (INIS)

North, Matthew; Shuga, Joe; Fromowitz, Michele; Loguinov, Alexandre; Shannon, Kevin; Zhang, Luoping; Smith, Martyn T; Vulpe, Chris D

2014-01-01

Benzene is an established human leukemogen, with a ubiquitous environmental presence leading to significant population exposure. In a genome-wide functional screen in the yeast Saccharomyces cerevisiae, inactivation of IRA2, a yeast ortholog of the human tumor suppressor gene NF1 (Neurofibromin), enhanced sensitivity to hydroquinone, an important benzene metabolite. Increased Ras signaling is implicated as a causal factor in the increased pre-disposition to leukemia of individuals with mutations in NF1. Growth inhibition of yeast by hydroquinone was assessed in mutant strains exhibiting varying levels of Ras activity. Subsequently, effects of hydroquinone on both genotoxicity (measured by micronucleus formation) and proliferation of WT and Nf1 null murine hematopoietic precursors were assessed. Here we show that the Ras status of both yeast and mammalian cells modulates hydroquinone toxicity, indicating potential synergy between Ras signaling and benzene toxicity. Specifically, enhanced Ras signaling increases both hydroquinone-mediated growth inhibition in yeast and genotoxicity in mammalian hematopoetic precursors as measured by an in vitro erythroid micronucleus assay. Hydroquinone also increases proliferation of CFU-GM progenitor cells in mice with Nf1 null bone marrow relative to WT, the same cell type associated with benzene-associated leukemia. Together our findings show that hydroquinone toxicity is modulated by Ras signaling. Individuals with abnormal Ras signaling could be more vulnerable to developing myeloid diseases after exposure to benzene. We note that hydroquinone is used cosmetically as a skin-bleaching agent, including by individuals with cafe-au-lait spots (which may be present in individuals with neurofibromatosis who have a mutation in NF1), which could be unadvisable given our findings

Putting together a plasma membrane NADH oxidase: a tale of three laboratories.

Science.gov (United States)

Löw, Hans; Crane, Frederick L; Morré, D James

2012-11-01

The observation that high cellular concentrations of NADH were associated with low adenylate cyclase activity led to a search for the mechanism of the effect. Since cyclase is in the plasma membrane, we considered the membrane might have a site for NADH action, and that NADH might be oxidized at that site. A test for NADH oxidase showed very low activity, which could be increased by adding growth factors. The plasma membrane oxidase was not inhibited by inhibitors of mitochondrial NADH oxidase such as cyanide, rotenone or antimycin. Stimulation of the plasma membrane oxidase by iso-proterenol or triiodothyronine was different from lack of stimulation in endoplasmic reticulum. After 25 years of research, three components of a trans membrane NADH oxidase have been discovered. Flavoprotein NADH coenzyme Q reductases (NADH cytochrome b reductase) on the inside, coenzyme Q in the middle, and a coenzyme Q oxidase on the outside as a terminal oxidase. The external oxidase segment is a copper protein with unique properties in timekeeping, protein disulfide isomerase and endogenous NADH oxidase activity, which affords a mechanism for control of cell growth by the overall NADH oxidase and the remarkable inhibition of oxidase activity and growth of cancer cells by a wide range of anti-tumor drugs. A second trans plasma membrane electron transport system has been found in voltage dependent anion channel (VDAC), which has NADH ferricyanide reductase activity. This activity must be considered in relation to ferricyanide stimulation of growth and increased VDAC antibodies in patients with autism. Copyright © 2012 Elsevier Ltd. All rights reserved.

Live cell imaging of cytosolic NADH/NAD+ ratio in hepatocytes and liver slices.

Science.gov (United States)

Masia, Ricard; McCarty, William J; Lahmann, Carolina; Luther, Jay; Chung, Raymond T; Yarmush, Martin L; Yellen, Gary

2018-01-01

Fatty liver disease (FLD), the most common chronic liver disease in the United States, may be caused by alcohol or the metabolic syndrome. Alcohol is oxidized in the cytosol of hepatocytes by alcohol dehydrogenase (ADH), which generates NADH and increases cytosolic NADH/NAD + ratio. The increased ratio may be important for development of FLD, but our ability to examine this question is hindered by methodological limitations. To address this, we used the genetically encoded fluorescent sensor Peredox to obtain dynamic, real-time measurements of cytosolic NADH/NAD + ratio in living hepatocytes. Peredox was expressed in dissociated rat hepatocytes and HepG2 cells by transfection, and in mouse liver slices by tail-vein injection of adeno-associated virus (AAV)-encoded sensor. Under control conditions, hepatocytes and liver slices exhibit a relatively low (oxidized) cytosolic NADH/NAD + ratio as reported by Peredox. The ratio responds rapidly and reversibly to substrates of lactate dehydrogenase (LDH) and sorbitol dehydrogenase (SDH). Ethanol causes a robust dose-dependent increase in cytosolic NADH/NAD + ratio, and this increase is mitigated by the presence of NAD + -generating substrates of LDH or SDH. In contrast to hepatocytes and slices, HepG2 cells exhibit a relatively high (reduced) ratio and show minimal responses to substrates of ADH and SDH. In slices, we show that comparable results are obtained with epifluorescence imaging and two-photon fluorescence lifetime imaging (2p-FLIM). Live cell imaging with Peredox is a promising new approach to investigate cytosolic NADH/NAD + ratio in hepatocytes. Imaging in liver slices is particularly attractive because it allows preservation of liver microanatomy and metabolic zonation of hepatocytes. NEW & NOTEWORTHY We describe and validate a new approach for measuring free cytosolic NADH/NAD + ratio in hepatocytes and liver slices: live cell imaging with the fluorescent biosensor Peredox. This approach yields dynamic, real-time

Cold stress decreases the capacity for respiratory NADH oxidation in potato leaves

DEFF Research Database (Denmark)

Svensson, Å.S.; Johansson, F.I.; Møller, I.M.

2002-01-01

is 10% of the original level. This decrease is accompanied by specific decreases of immunodetected NDA protein and internal rotenone-insensitive NADH oxidation in mitochondria isolated from cold-treated plants. The alternative oxidase is not cold-induced neither at the protein nor at the activity level......Cold stress effects on the expression of genes for respiratory chain enzymes were investigated in potato (Solarium tuberosum L., cv. Desiree) leaves. The nda1 and ndb1 genes, homologues to genes encoding the non-proton-pumping respiratory chain NADH dehydrogenases of Escherichia coli and yeast......, were compared to genes encoding catalytic subunits of the proton-pumping NADH dehydrogenase (complex I). Using a real-time PCR system, we demonstrate a specific and gradual decrease of the NDA1 transcript after exposing the plants to 5 C. After 6 days of cold treatment the NDA1 transcript abundance...

Fluorescence lifetime microscopy of NADH distinguishes alterations in cerebral metabolism in vivo.

Science.gov (United States)

Yaseen, Mohammad A; Sutin, Jason; Wu, Weicheng; Fu, Buyin; Uhlirova, Hana; Devor, Anna; Boas, David A; Sakadžić, Sava

2017-05-01

Evaluating cerebral energy metabolism at microscopic resolution is important for comprehensively understanding healthy brain function and its pathological alterations. Here, we resolve specific alterations in cerebral metabolism in vivo in Sprague Dawley rats utilizing minimally-invasive 2-photon fluorescence lifetime imaging (2P-FLIM) measurements of reduced nicotinamide adenine dinucleotide (NADH) fluorescence. Time-resolved fluorescence lifetime measurements enable distinction of different components contributing to NADH autofluorescence. Ostensibly, these components indicate different enzyme-bound formulations of NADH. We observed distinct variations in the relative proportions of these components before and after pharmacological-induced impairments to several reactions involved in glycolytic and oxidative metabolism. Classification models were developed with the experimental data and used to predict the metabolic impairments induced during separate experiments involving bicuculline-induced seizures. The models consistently predicted that prolonged focal seizure activity results in impaired activity in the electron transport chain, likely the consequence of inadequate oxygen supply. 2P-FLIM observations of cerebral NADH will help advance our understanding of cerebral energetics at a microscopic scale. Such knowledge will aid in our evaluation of healthy and diseased cerebral physiology and guide diagnostic and therapeutic strategies that target cerebral energetics.

Simultaneous Determination of Hydroquinone and Catechol by Poly (L-methionine Coated Hydroxyl Multiwalled Carbon Nanotube Film

Directory of Open Access Journals (Sweden)

Ying Zhang

2014-07-01

Full Text Available A simply and high selectively electrochemical method has been developed for the simultaneous determination of hydroquinone and catechol at a glassy carbon electrode modified with the poly L-methionine/multiwall carbon nanotubes, which significantly increased the reversible electrochemical reaction. The electrochemical behavior of catechol and hydroquinone at the modified electrode was studied by cyclic voltammetry and differential pulse voltammetry. The presence of hydroxyl MWCNTs in the composite film enhances the surface coverage concentration of poly L- methionine/multiwall carbon nanotubes. The results suggest that pH=6 is the optimum acidity condition for the selective and simultaneous determination of catechol and hydroquinone. Under the optimized condition, the response peak currents of the modified electrodes were linear over ranges of 8.0´10-7~2.0´10-4 mol/L (R2=0.997 for hydroquinone and 8.0´10-7~2.0´10-4, R2=0.997 for catechol. The sensor also exhibited good sensitivity with the detection limit of 8.0´10-8 mol/L and 1.0´10- 7 mol/L for hydroquinone and catechol, respectively. This study provides a new kind of composite modified electrode for electrochemical sensors with good selectivity and strong anti- interference. It has been applied to simultaneous determination of hydroquinone and catechol in water sample with simplicity and high selectivity.

The first clinical experience on efficacy of topical flutamide on melasma compared with topical hydroquinone: a randomized clinical trial

Directory of Open Access Journals (Sweden)

Adalatkhah H

2015-08-01

Full Text Available Hassan Adalatkhah,1 Homayoun Sadeghi-Bazargani2,3 1Department of Dermatology, Ardabil University of Medical Sciences, Ardabil, Iran; 2Road Traffic Injury Research Center, Department of Statistics and Epidemiology, Tabriz University of Medical Sciences, Tabriz, Iran; 3Department of Public Health Sciences, Karolinska Institute, Stockholm, Sweden Background: Treatment of melasma is unsatisfactory most of the times. Hormonal role is shown to exist in pathogenesis of the melasma, and sex-hormone related drugs may have an effect on melasma.Aim: To investigate efficacy of 1% flutamide cream versus 4% hydroquinone cream on melasma.Methods: In a parallel randomized clinical trial, 74 women with melasma were allocated to receive a sunscreen along with 4% hydroquinone cream or 1% flutamide cream. Melasma Area and Severity Index (MASI, mexameter melanin assay, and patient satisfaction were investigated.Results: Mean age of the participants was 33.8 years. Mean length of time suffering from Melasma was 96.3 months. The subjects reported in average 1.1 hours per day of exposure to sunlight. Mean standardized total patient satisfaction score was 28.8 (standard deviation [SD] 17.2 in flutamide group patients versus 18 (SD 15.5 in control group (P<0.01. Regardless of treatment group, the skin darkness assessed upon MASI scales was reduced over the treatment course (P<0.001. Using mixed effects, longitudinal modeling showed better treatment efficacy based on MASI scale for flutamide group compared to the hydroquinone group (P<0.05. However, longitudinal analysis of mexameter scores did not reveal any significant difference in melanin measurements between flutamide and hydroquinone.Conclusion: Topical flutamide appeared as effective as topical hydroquinone in treating melasma using mexameter assessment but with a better MASI improvement trend and higher patient satisfaction in flutamide treatment versus topical hydroquinone. As the present study is possibly the

Crystallization and preliminary crystallographic analysis of a flavoprotein NADH oxidase from Lactobacillus brevis

International Nuclear Information System (INIS)

Kuzu, Mutlu; Niefind, Karsten; Hummel, Werner; Schomburg, Dietmar

2005-01-01

The water-forming flavoenzyme NADH oxidase was crystallized successfully for the first time. The crystals diffract X-rays to at least 4.0 Å resolution. NADH oxidase (NOX) from Lactobacillus brevis is a homotetrameric flavoenzyme composed of 450 amino acids per subunit. The molecular weight of each monomer is 48.8 kDa. The enzyme catalyzes the oxidation of two equivalents of NADH and reduces one equivalent of oxygen to yield two equivalents of water, without releasing hydrogen peroxide after the reduction of the first equivalent of NADH. Crystals of this protein were grown in the presence of 34% polyethylene glycol monomethyl ether 2000, 0.1 M sodium acetate and 0.2 M ammonium sulfate at pH 5.4. They belong to the tetragonal space group P4 3 2 1 2, with unit-cell parameters a = 74.8, b = 95.7, c = 116.9 Å, α = γ = 90, β = 103.8°. The current diffraction limit is 4.0 Å. The self-rotation function of the native data set is consistent with a NOX tetramer in the asymmetric unit

Influence of oxygen on NADH recycling and oxidative stress resistance systems in Lactobacillus panis PM1.

Science.gov (United States)

Kang, Tae Sun; Korber, Darren R; Tanaka, Takuji

2013-01-31

Lactobacillus panis strain PM1 is an obligatory heterofermentative and aerotolerant microorganism that also produces 1,3-propanediol from glycerol. This study investigated the metabolic responses of L. panis PM1 to oxidative stress under aerobic conditions. Growth under aerobic culture triggered an early entrance of L. panis PM1 into the stationary phase along with marked changes in end-product profiles. A ten-fold higher concentration of hydrogen peroxide was accumulated during aerobic culture compared to microaerobic culture. This H2O2 level was sufficient for the complete inhibition of L. panis PM1 cell growth, along with a significant reduction in end-products typically found during anaerobic growth. In silico analysis revealed that L. panis possessed two genes for NADH oxidase and NADH peroxidase, but their expression levels were not significantly affected by the presence of oxygen. Specific activities for these two enzymes were observed in crude extracts from L. panis PM1. Enzyme assays demonstrated that the majority of the H2O2 in the culture media was the product of NADH: H2O2 oxidase which was constitutively-active under both aerobic and microaerobic conditions; whereas, NADH peroxidase was positively-activated by the presence of oxygen and had a long induction time in contrast to NADH oxidase. These observations indicated that a coupled NADH oxidase - NADH peroxidase system was the main oxidative stress resistance mechanism in L. panis PM1, and was regulated by oxygen availability. Under aerobic conditions, NADH is mainly reoxidized by the NADH oxidase - peroxidase system rather than through the production of ethanol (or 1,3-propanediol or succinic acid production if glycerol or citric acid is available). This system helped L. panis PM1 directly use oxygen in its energy metabolism by producing extra ATP in contrast to homofermentative lactobacilli.

A high effective NADH-ferricyanide dehydrogenase coupled with laccase for NAD(+) regeneration.

Science.gov (United States)

Wang, Jizhong; Yang, Chengli; Chen, Xing; Bao, Bingxin; Zhang, Xuan; Li, Dali; Du, Xingfan; Shi, Ruofu; Yang, Junfang; Zhu, Ronghui

2016-08-01

To find an efficient and cheap system for NAD(+) regeneration A NADH-ferricyanide dehydrogenase was obtained from an isolate of Escherichia coli. Optimal activity of the NADH dehydrogenase was at 45 °C and pH 7.5, with a K m value for NADH of 10 μM. By combining the NADH dehydrogenase, potassium ferricyanide and laccase, a bi-enzyme system for NAD(+) regeneration was established. The system is attractive in that the O2 consumed by laccase is from air and the sole byproduct of the reaction is water. During the reaction process, 10 mM NAD(+) was transformed from NADH in less than 2 h under the condition of 0.5 U NADH dehydrogenase, 0.5 U laccase, 0.1 mM potassium ferricyanide at pH 5.6, 30 °C CONCLUSION: The bi-enzyme system employed the NADH-ferricyanide dehydrogenase and laccase as catalysts, and potassium ferricyanide as redox mediator, is a promising alternative for NAD(+) regeneration.

Small structural changes on a hydroquinone scaffold determine the complex I inhibition or uncoupling of tumoral oxidative phosphorylation

Energy Technology Data Exchange (ETDEWEB)

Urra, Félix A., E-mail: felix.urra@qf.uchile.cl [Programa de Farmacología Molecular y Clínica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Independencia 1027, Casilla 7, Santiago (Chile); Córdova-Delgado, Miguel [Departamento de Química Orgánica y Físico-Química, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago 1 (Chile); Lapier, Michel; Orellana-Manzano, Andrea [Programa de Farmacología Molecular y Clínica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Independencia 1027, Casilla 7, Santiago (Chile); Acevedo-Arévalo, Luis; Pessoa-Mahana, Hernán; González-Vivanco, Jaime M. [Departamento de Química Orgánica y Físico-Química, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago 1 (Chile); Martínez-Cifuentes, Maximiliano [Instituto de Química de Recursos Naturales, Universidad de Talca, Casilla 747, Talca (Chile); and others

2016-01-15

Mitochondria participate in several distinctiveness of cancer cell, being a promising target for the design of anti-cancer compounds. Previously, we described that ortho-carbonyl hydroquinone scaffold 14 inhibits the complex I-dependent respiration with selective anti-proliferative effect on mouse mammary adenocarcinoma TA3/Ha cancer cells; however, the structural requirements of this hydroquinone scaffold to affect the oxidative phosphorylation (OXPHOS) of cancer cells have not been studied in detail. Here, we characterize the mitochondrial metabolism of TA3/Ha cancer cells, which exhibit a high oxidative metabolism, and evaluate the effect of small structural changes of the hydroquinone scaffold 14 on the respiration of this cell line. Our results indicate that these structural changes modify the effect on OXPHOS, obtaining compounds with three alternative actions: inhibitors of complex I-dependent respiration, uncoupler of OXPHOS and compounds with both actions. To confirm this, the effect of a bicyclic hydroquinone (9) was evaluated in isolated mitochondria. Hydroquinone 9 increased mitochondrial respiration in state 4o without effects on the ADP-stimulated respiration (state 3{sub ADP}), decreasing the complexes I and II-dependent respiratory control ratio. The effect on mitochondrial respiration was reversed by 6-ketocholestanol addition, indicating that this hydroquinone is a protonophoric uncoupling agent. In intact TA3/Ha cells, hydroquinone 9 caused mitochondrial depolarization, decreasing intracellular ATP and NAD(P)H levels and GSH/GSSG ratio, and slightly increasing the ROS levels. Moreover, it exhibited selective NAD(P)H availability-dependent anti-proliferative effect on cancer cells. Therefore, our results indicate that the ortho-carbonyl hydroquinone scaffold offers the possibility to design compounds with specific actions on OXPHOS of cancer cells. - Highlights: • Small changes on a hydroquinone scaffold modify the action on OXPHOS of cancer

A radiometric method for the determination of NADH in subpicomole amounts

International Nuclear Information System (INIS)

Weber, G.; Rosenthal, W.; Oberdisse, E.

1988-01-01

A radiometric method has been devised for the determination of small quantities of NADH formed in preceding dehydrogenase reactions. In a coupled enzymatic reaction, phosphoglycerate kinase (PGK) catalyzes the transfer of [/sup 32/P]orthophosphate from [gamma-/sup 32/P]ATP to 3-phosphoglycerate; the intermediate, 1,3-[1-/sup 32/P]diphosphoglycerate, is dephosphorylated by glyceraldehyde-3-phosphate dehydrogenase (GAP-DH). [/sup 32/P]Orthophosphate is released proportionally to NADH and can be measured after adsorption of [gamma-/sup 32/P]ATP to activated charcoal. With this method, 0.2 pmol of NADH are detectable in the presence of a 10/sup 4/-fold excess of NAD over NADH

Characterization of Frex as an NADH sensor for in vivo applications in the presence of NAD+ and at various pH values.

Science.gov (United States)

Wilkening, Svea; Schmitt, Franz-Josef; Horch, Marius; Zebger, Ingo; Lenz, Oliver; Friedrich, Thomas

2017-09-01

The fluorescent biosensor Frex, recently introduced as a sensitive tool to quantify the NADH concentration in living cells, was characterized by time-integrated and time-resolved fluorescence spectroscopy regarding its applicability for in vivo measurements. Based on the purified sensor protein, it is shown that the NADH dependence of Frex fluorescence can be described by a Hill function with a concentration of half-maximal sensor response of K D  ≈ 4 µM and a Hill coefficient of n ≈ 2. Increasing concentrations of NADH have moderate effects on the fluorescence lifetime of Frex, which changes by a factor of two from about 500 ps in the absence of NADH to 1 ns under fluorescence-saturating NADH concentrations. Therefore, the observed sevenfold rise of the fluorescence intensity is primarily ascribed to amplitude changes. Notably, the dynamic range of Frex sensitivity towards NADH highly depends on the NAD + concentration, while the apparent K D for NADH is only slightly affected. We found that NAD + has a strong inhibitory effect on the fluorescence response of Frex during NADH sensing, with an apparent NAD + dissociation constant of K I  ≈ 400 µM. This finding was supported by fluorescence lifetime measurements, which showed that the addition of NAD + hardly affects the fluorescence lifetime, but rather reduces the number of Frex molecules that are able to bind NADH. Furthermore, the fluorescence responses of Frex to NADH and NAD + depend critically on pH and temperature. Thus, for in vivo applications of Frex, temperature and pH need to be strictly controlled or considered during data acquisition and analysis. If all these constraints are properly met, Frex fluorescence intensity measurements can be employed to estimate the minimum NADH concentration present within the cell at sufficiently low NAD + concentrations below 100 µM.

HPLC-UV Method for the Identification and Screening of Hydroquinone, Ethers of Hydroquinone and Corticosteroids Possibly Used as Skin-Whitening Agents in Illicit Cosmetic Products.

Science.gov (United States)

Gimeno, Pascal; Maggio, Annie-Françoise; Bancilhon, Marjorie; Lassu, Nelly; Gornes, Hervé; Brenier, Charlotte; Lempereur, Laurent

2016-03-01

Corticosteroids, hydroquinone and its ethers are regulated in cosmetics by the Regulation 1223/2009. As corticosteroids are forbidden to be used in cosmetics and cannot be present as contaminants or impurities, an identification of one of these illicit compounds deliberately introduced in these types of cosmetics is enough for market survey control. In order to quickly identify skin-whitening agents present in illegal cosmetics, this article proposes an HPLC-UV method for the identification and screening of hydroquinone, 3 ethers of hydroquinone and 39 corticosteroids that may be found in skin-whitening products. Two elution gradients were developed to separate all compounds. The main solvent gradient (A) allows the separation of 39 compounds among the 43 compounds considered in 50 min. Limits of detection on skin-whitening cosmetics are given. For compounds not separated, a complementary gradient elution (B) using the same solvents is proposed. Between 2004 and 2009, a market survey on "skin-whitening cosmetic" was performed on 150 samples and highlights that more than half of the products tested do not comply with the Cosmetic Regulation 1223/2009 (amending the Council Directive 76/768/EEC). © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Investigation of the Ionization Mechanism of NAD+/NADH-Modified Gold Electrodes in ToF-SIMS Analysis.

Science.gov (United States)

Hua, Xin; Zhao, Li-Jun; Long, Yi-Tao

2018-06-04

Analysis of nicotinamide adenine dinucleotide (NAD + /NADH)-modified electrodes is important for in vitro monitoring of key biological processes. In this work, time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to analyze NAD + /NADH-modified gold electrodes. Interestingly, no obvious characteristic peaks of nicotinamide fragment could be observed in the mass spectra of NAD + /NADH in their neutral sodium pyrophosphate form. However, after acidification, the characteristic peaks for both NAD + and NADH were detected. This was due to the suppression effect of inner pyrophosphoric salts in both neutral molecules. Besides, it was proved that the suppression by inner salt was intramolecular. No obvious suppression was found between neighboring molecules. These results demonstrated the suppression effect of inner salts in ToF-SIMS analysis, providing useful evidence for the study of ToF-SIMS ionization mechanism of organic molecule-modified electrodes. Graphical Abstract ᅟ.

Nitration of phenolic compounds and oxidation of hydroquinones ...

Indian Academy of Sciences (India)

Abstract. In this work, we have reported a mild, efficient and selective method for the mononitration of phenolic compounds using sodium nitrite in the presence of tetrabutylammonium dichromate (TBAD) and oxidation of hydroquinones to quinones with TBAD in CH2Cl2. Using this method, high yields of nitrophenols and ...

Quantitative analysis of arbutin and hydroquinone in strawberry tree (Arbutus unedo L., Ericaceae) leaves by gas chromatography-mass spectrometry.

Science.gov (United States)

Jurica, Karlo; Karačonji, Irena Brčić; Šegan, Sandra; Opsenica, Dušanka Milojković; Kremer, Dario

2015-09-01

The phenolic glycoside arbutin and its metabolite with uroantiseptic activity hydroquinone occur naturally in the leaves of various medicinal plants and spices. In this study, an extraction procedure coupled with gas chromatography-mass spectrometry (GC-MS) was developed to determine arbutin and hydroquinone content in strawberry tree (Arbutus unedo L., Ericaceae) leaves. The method showed good linearity (R2>0.9987) in the tested concentration range (0.5-200 μg mL(-1)), as well as good precision (RSD<5%), analytical recovery (96.2-98.0%), and sensitivity (limit of detection=0.009 and 0.004 μg mL(-1) for arbutin and hydroquinone, respectively). The results obtained by the validated GC-MS method corresponded well to those obtained by high performance liquid chromatography (HPLC) method. The proposed method was then applied for determining arbutin and hydroquinone content in methanolic leaf extracts. The amount of arbutin in the leaves collected on the island of Koločep (6.82 mg g(-1) dry weight) was found to be higher (tpaired=43.57, tc=2.92) in comparison to the amount of arbutin in the leaves collected on the island of Mali Lošinj (2.75 mg g(-1) dry weight). Hydroquinone was not detected in any of the samples. The analytical features of the proposed GC-MS method demonstrated that arbutin and hydroquinone could be determined alternatively by gas chromatography. Due to its wide concentration range, the method could also be suitable for arbutin and hydroquinone analysis in leaves of other plant families (Rosaceae, Lamiaceae, etc.).

Regulation of hydrogen production by Enterobacter aerogenes by external NADH and NAD{sup +}

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chong; Ma, Kun; Xing, Xin-Hui [Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China)

2009-02-15

Experiments involving the addition of external nicotinamide adenine dinucleotide, reduced form (NADH) or nicotinamide adenine dinucleotide (NAD{sup +}) have been designed to examine how the hydrogen in Enterobacter aerogenes is liberated by NADH or NAD{sup +}. The addition of external NADH or NAD{sup +} was found to regulate hydrogen production by E. aerogenes in resting cells, batch cultures, and chemostat cultures. Particularly in chemostat cultivation, with the external addition of NADH, hydrogen production via the NADH pathway was decreased, while that via the formate pathway was increased; in the end, the overall hydrogen p was decreased. The addition of NAD{sup +}, on the other hand, gave the opposite results. The membrane-bound hydrogenase was found to play a central role in regulating hydrogen production. The occurrence of NADH oxidation (NAD{sup +} reduction) on the cell membrane resulted in an electron flow across the membrane; this changed the oxidation state and metabolic pattern of the cells, which eventually affected the hydrogen evolution. (author)

Overexpression of a novel endogenous NADH kinase in Aspergillus nidulans enhances growth

DEFF Research Database (Denmark)

Panagiotou, Gianni; Grotkjær, Thomas; Hofmann, Gerald

2009-01-01

.7.1.86) has been identified. The enzyme has a predicted molecular weight of 49 kDa. We characterised the role of this NADH kinase by genomic integration of the putative gene AN8837.2 under a strong constitutive promoter. The physiological effects of overexpressed NADH kinase in combination with different...... yield on glucose and the maximum specific growth rate increased from 0.47 g/g and 0.22 h(-1) (wild type) to 0.54 g/g and 0.26 h(-1) (NADH kinase overexpressed), respectively. The results suggest that overexpression of NADH kinase improves the growth efficiency of the cell by increasing the access...

The development of the time-keeping clock with TS-1 single chip microcomputer.

Science.gov (United States)

Zhou, Jiguang; Li, Yongan

The authors have developed a time-keeping clock with Intel 8751 single chip microcomputer that has been successfully used in time-keeping station. The hard-soft ware design and performance of the clock are introduced.

The increase of NADH fluorescence lifetime is associated with the metabolic change during osteogenic differentiation of human mesenchymal stem cells (hMSCs)

Science.gov (United States)

Guo, Han Wen; Yu, Jia Sin; Hsu, Shu Han; Wei, Yau Huei; Lee, Oscar K.; Wang, Hsing Wen

2011-03-01

Fluorescence lifetime of NADH had been used as an optical marker for monitoring cellular metabolism. In our pervious studies, we have demonstrated that NADH lifetime of hMSCs increase gradually with time of osteogenic differentiation. In this study, we measured NADH lifetime of hMSCs from a different donor as well as the corresponding metabolic indices such as ATP level, oxygen consumption and lactate release. We also measure the quantity of Complex I, III, IV and V. The results show that during differentiation more oxygen consumed, higher ATP level expressed and less lactate released, and the increase of NADH lifetime was associated with ATP level. Higher expression of the total Complex protein was observed at 3 and 4 weeks after differentiation than controls. However, Complex I expression did not show significant correlation with the increase of NADH fluorescence lifetime. In summary, we demonstrated that the change of NADH lifetime was associated with the metabolic change during osteogenic differentiation of hMSCs. The increase of NADH lifetime was in part due to the increased Complex protein interaction in mitochondria after differentiation.

Metabolic control by sirtuins and other enzymes that sense NAD+, NADH, or their ratio.

Science.gov (United States)

Anderson, Kristin A; Madsen, Andreas S; Olsen, Christian A; Hirschey, Matthew D

2017-12-01

NAD + is a dinucleotide cofactor with the potential to accept electrons in a variety of cellular reduction-oxidation (redox) reactions. In its reduced form, NADH is a ubiquitous cellular electron donor. NAD + , NADH, and the NAD + /NADH ratio have long been known to control the activity of several oxidoreductase enzymes. More recently, enzymes outside those participating directly in redox control have been identified that sense these dinucleotides, including the sirtuin family of NAD + -dependent protein deacylases. In this review, we highlight examples of non-redox enzymes that are controlled by NAD + , NADH, or NAD + /NADH. In particular, we focus on the sirtuin family and assess the current evidence that the sirtuin enzymes sense these dinucleotides and discuss the biological conditions under which this might occur; we conclude that sirtuins sense NAD + , but neither NADH nor the ratio. Finally, we identify future studies that might be informative to further interrogate physiological and pathophysiological changes in NAD + and NADH, as well as enzymes like sirtuins that sense and respond to redox changes in the cell. Copyright © 2017 Elsevier B.V. All rights reserved.

Metabolic control by sirtuins and other enzymes that sense NAD(+), NADH, or their ratio

DEFF Research Database (Denmark)

Anderson, Kristin A; Madsen, Andreas S; Olsen, Christian A

2017-01-01

NAD(+) is a dinucleotide cofactor with the potential to accept electrons in a variety of cellular reduction-oxidation (redox) reactions. In its reduced form, NADH is a ubiquitous cellular electron donor. NAD(+), NADH, and the NAD(+)/NADH ratio have long been known to control the activity of several...... oxidoreductase enzymes. More recently, enzymes outside those participating directly in redox control have been identified that sense these dinucleotides, including the sirtuin family of NAD(+)-dependent protein deacylases. In this review, we highlight examples of non-redox enzymes that are controlled by NAD......(+), NADH, or NAD(+)/NADH. In particular, we focus on the sirtuin family and assess the current evidence that the sirtuin enzymes sense these dinucleotides and discuss the biological conditions under which this might occur; we conclude that sirtuins sense NAD(+), but neither NADH nor the ratio. Finally, we...

Inhibition of NADH-ubiquinone reductase activity by N,N'-dicyclohexylcarbodiimide and correlation of this inhibition with the occurrence of energy-coupling site 1 in various organisms

International Nuclear Information System (INIS)

Yagi, T.

1987-01-01

The NADH-ubiquinone reductase activity of the respiratory chains of several organisms was inhibited by the carboxyl-modifying reagent N,N'-dicyclohexylcarbodiimide (DCCD). This inhibition correlated with the presence of an energy-transducing site in this segment of the respiratory chain. Where the NADH-quinone reductase segment involved an energy-coupling site (e.g., in bovine heart and rat liver mitochondria, and in Paracoccus denitrificans, Escherichia coli, and Thermus thermophilus HB-8 membranes), DCCD acted as an inhibitor of ubiquinone reduction by NADH. By contrast, where energy-coupling site 1 was absent (e.g., in Saccharomyces cerevisiae mitochondria and BacilLus subtilis membranes), there was no inhibition of NADH-ubiquinone reductase activity by DCCD. In the bovine and P. denitrificans systems, DCCD inhibition was pseudo first order with respect to incubation time, and reaction order with respect to inhibitor concentration was close to unity, indicating that inhibition resulted from the binding of one inhibitor molecule per active unit of NADH-ubiquinone reductase. In the bovine NADH-ubiquinone reductase complex (complex I), [ 14 C]DCCD was preferentially incorporated into two subunits of molecular weight 49,000 and 29,000. The time course of labeling of the 29,000 molecular weight subunit with [ 14 C]DCCD paralleled the time course of inhibition of NADH-ubiquinone reductase activity

Cofactor engineering to regulate NAD+/NADH ratio with its application to phytosterols biotransformation.

Science.gov (United States)

Su, Liqiu; Shen, Yanbing; Zhang, Wenkai; Gao, Tian; Shang, Zhihua; Wang, Min

2017-10-30

Cofactor engineering is involved in the modification of enzymes related to nicotinamide adenine dinucleotides (NADH and NAD + ) metabolism, which results in a significantly altered spectrum of metabolic products. Cofactor engineering plays an important role in metabolic engineering but is rarely reported in the sterols biotransformation process owing to its use of multi-catabolic enzymes, which promote multiple consecutive reactions. Androst-4-ene-3, 17-dione (AD) and androst-1, 4-diene-3, 17-dione (ADD) are important steroid medicine intermediates that are obtained via the nucleus oxidation and the side chain degradation of phytosterols by Mycobacterium. Given that the biotransformation from phytosterols to AD (D) is supposed to be a NAD + -dependent process, this work utilized cofactor engineering in Mycobacterium neoaurum and investigated the effect on cofactor and phytosterols metabolism. Through the addition of the coenzyme precursor of nicotinic acid in the phytosterols fermentation system, the intracellular NAD + /NADH ratio and the AD (D) production of M. neoaurum TCCC 11978 (MNR M3) were higher than in the control. Moreover, the NADH: flavin oxidoreductase was identified and was supposed to exert a positive effect on cofactor regulation and phytosterols metabolism pathways via comparative proteomic profiling of MNR cultured with and without phytosterols. In addition, the NADH: flavin oxidoreductase and a water-forming NADH oxidase from Lactobacillus brevis, were successfully overexpressed and heterologously expressed in MNR M3 to improve the intracellular ratio of NAD + /NADH. After 96 h of cultivation, the expression of these two enzymes in MNR M3 resulted in the decrease in intracellular NADH level (by 51 and 67%, respectively) and the increase in NAD + /NADH ratio (by 113 and 192%, respectively). Phytosterols bioconversion revealed that the conversion ratio of engineered stains was ultimately improved by 58 and 147%, respectively. The highest AD (D

How Does My Cellphone GPS Work?-The Physics of Precision Time-Keeping

Science.gov (United States)

Chu, Steven

The most precise measurements in all of science are frequency and frequency difference measurements, or alternatively, phase and phase change of electromagnetic waves. Improvements in time-keeping have opened up many horizons in fundamental and applied physics that range from the detection of gravity waves to the melting of glaciers and the depletion of underground aquifers. Precision time keeping has also had important practical applications such as in the navigation, beginning with the determination of the longitude position of sailing ships. We now use our cell phones to help us navigate city streets and hail taxis from Uber and Lyft based on our geographical position within a few meters. How did this come about? What will the new time-keeping technologies enable in the future?

Identification of NADH kinase activity in filamentous fungi and structural modelling of the novel enzyme from Fusarium oxysporum

DEFF Research Database (Denmark)

Panagiotou, Gianni; Papadakis, Emmanouil; Topakas, E.

2008-01-01

ATP-NADH kinase phosphorylates NADH to produce NADPH at the expense of ATP. The present study describes Fusarium oxysporum NADH kinase (ATP:NADH 2'-phosphotransferase, EC 2.7.1.86), a novel fungal enzyme capable of synthesizing NADPH using NADH as the preferred diphosphonicotinamide...

A strategy to promote the electroactive platform adopting poly(o-anisidine)-silver nanocomposites probed for the voltammetric detection of NADH and dopamine.

Science.gov (United States)

Sangamithirai, D; Munusamy, S; Narayanan, V; Stephen, A

2017-11-01

A study on the voltammetric detection of NADH (β-nicotinamide adenine dinucleotide), Dopamine (DA) and their simultaneous determination is presented in this work. The electrochemical sensor was fabricated with the hybrid nanocomposites of poly(o-anisidine) and silver nanoparticles prepared by simple and cost-effective insitu chemical oxidative polymerization technique. The nanocomposites were synthesized with different (w/w) ratios of o-anisidine and silver by increasing the amount of o-anisidine in each, by keeping silver at a fixed quantity. The XRD patterns revealed the semi-crystalline nature of poly(o-anisidine) and the face centered cubic structure of silver. The presence of silver in its metallic state and the formation of nanocomposite were established by XPS analysis. Raman studies suggested the presence of site-selective interaction between poly(o-anisidine) and silver. HRTEM studies revealed the formation of polymer matrix type nanocomposite with the embedment of silver nanoparticles. The sensing performance of the materials were studied via cyclic voltammetry, differential pulse voltammetry and chronoamperometry techniques. Fabricated sensor with 3:1 (w/w) ratio of poly(o-anisidine) and silver exhibited good catalytic activity towards the detection of NADH and DA in terms of potential and current response, when compared to others. Several important electrochemical parameters regulating the performance of the sensor have been evaluated. Under the optimum condition, differential pulse voltammetry method exhibited the linear response in the range of 0.03 to 900μM and 5 to 270μM with a low detection limit of 0.006μM and 0.052μM for NADH and DA, respectively. The modified electrodes exhibited good sensitivity, stability, reproducibility and selectivity with well-separated oxidation peaks for NADH and DA in the simultaneous determination of their binary mixture. The analytical performance of the nanocomposite as an electrochemical sensor was also

Fungal hydroquinones contribute to brown rot of wood

Science.gov (United States)

Melissa R. Suzuki; Christopher G. Hunt; Carl J. Houtman; Zachary D. Dalebroux; Kenneth E. Hammel

2006-01-01

The fungi that cause brown rot of wood initiate lignocellulose breakdown with an extracellular Fenton system in which Fe2+ and H2O2 react to produce hydroxyl radicals (•OH), which then oxidize and cleave the wood holocellulose. One such fungus, Gloeophyllum trabeum, drives Fenton chemistry on defined media by reducing Fe3+ and O2 with two extracellular hydroquinones,...

Evaluation of functioning of mitochondrial electron transport chain with NADH and FAD autofluorescence

Science.gov (United States)

Danylovych, H V

2016-01-01

We prove the feasibility of evaluation of mitochondrial electron transport chain function in isolated mitochondria of smooth muscle cells of rats from uterus using fluorescence of NADH and FAD coenzymes. We found the inversely directed changes in FAD and NADH fluorescence intensity under normal functioning of mitochondrial electron transport chain. The targeted effect of inhibitors of complex I, III and IV changed fluorescence of adenine nucleotides. Rotenone (5 μM) induced rapid increase in NADH fluorescence due to inhibition of complex I, without changing in dynamics of FAD fluorescence increase. Antimycin A, a complex III inhibitor, in concentration of 1 μg/ml caused sharp increase in NADH fluorescence and moderate increase in FAD fluorescence in comparison to control. NaN3 (5 mM), a complex IV inhibitor, and CCCP (10 μM), a protonophore, caused decrease in NADH and FAD fluorescence. Moreover, all the inhibitors caused mitochondria swelling. NO donors, e.g. 0.1 mM sodium nitroprusside and sodium nitrite similarly to the effects of sodium azide. Energy-dependent Ca2+ accumulation in mitochondrial matrix (in presence of oxidation substrates and Mg-ATP2- complex) is associated with pronounced drop in NADH and FAD fluorescence followed by increased fluorescence of adenine nucleotides, which may be primarily due to Ca2+- dependent activation of dehydrogenases of citric acid cycle. Therefore, the fluorescent signal of FAD and NADH indicates changes in oxidation state of these nucleotides in isolated mitochondria, which may be used to assay the potential of effectors of electron transport chain.

The risks of external oculotoxicity in the usage of hydroquinone ...

African Journals Online (AJOL)

Among the dark skinned, it is described as a skin lightening substance when added to creams, soaps, lotions, gels and ointments. ... In addition, 25% became exposed to hydroquinone-containing products through personal knowledge while (65%) were through encouragement by friends and relations and 3.0% through the ...

NADH oxidation on screen-printed electrode modified with a new phenothiazine diazonium salt

Energy Technology Data Exchange (ETDEWEB)

Doumeche, Bastien; Blum, Loic J. [GEMBAS, Genie Enzymatique, Membranes Biomimetiques et Assemblages Supramoleculaires, ICBMS UMR 5246, Universite Lyon 1, 43 bd du 11 Novembre 1918, 69622 Villeurbanne (France)

2010-10-15

NADH oxidation catalysts are extremely important in the field of electrochemical biosensors and enzymatic biofuel cells. Based on the growing diazonium chemistry, we synthesized the diazonium salt of the well-known NADH mediator toluidine blue O. The electrochemical reduction of the diazonium moiety by cyclic voltammetry onto a screen-printed electrode leads to an electrocatalyst suitable for the oxidation of NADH. The amperometric response for its oxidation shows a maximal current of 1.2 {mu}A ([NADH] = 100 {mu}M). Based on electrochemical measurements, the surface coverage is found to be 3.78 x 10{sup -11} mol cm{sup -2} and the heterogeneous standard rate constant k{sub h} is 1.21 {+-} 0.16 s{sup -1}. The sensitive layer for the oxidation of NADH is improved by electrografting the diazonium salt with a potentiostatic method. Both the surface coverage and the heterogeneous standard rate constant k{sub h} are improved and found to be 6.08 {+-} 0.63 x 10{sup -11} mol cm{sup -2} and {proportional_to} 5.02 s{sup -} {sup 1}, respectively. The amperometric response is also improved by an 8 fold factor, reaching 9.87 {mu}A ([NADH] = 120 {mu}M). These remarkably high values for screen-printed electrodes are comparable to glassy carbon electrodes making this method suitable for low-cost bioelectronical devices. (author)

Comparative investigation on electrochemical behavior of hydroquinone at carbon ionic liquid electrode, ionic liquid modified carbon paste electrode and carbon paste electrode

International Nuclear Information System (INIS)

Zhang, Ya; Zheng, Jian Bin

2007-01-01

Ionic liquid, 1-heptyl-3-methylimidazolium hexafluorophosphate (HMIMPF 6 ), has been used to fabricate two new electrodes, carbon ionic liquid electrode (CILE) and ionic liquid modified carbon paste electrode (IL/CPE), using graphite powder mixed with HMIMPF 6 or the mixture of HMIMPF 6 /paraffin liquid as the binder, respectively. The electrochemical behaviors of hydroquinone at the CILE, the IL/CPE and the CPE were investigated in phosphate buffer solution. At all these electrodes, hydroquinone showed a pair of redox peaks. The order of the current response and the standard rate constant of hydroquinone at these electrodes were as follows: CILE > IL/CPE > CPE, while the peak-to-peak potential separation was in an opposite sequence: CILE < IL/CPE < CPE. The results show the superiority of CILE to IL/CPE and CPE, and IL/CPE to CPE in terms of promoting electron transfer, improving reversibility and enhancing sensitivity. The CILE was chosen as working electrode to determine hydroquinone by differential pulse voltammetry, which can be used for sensitive, simple and rapid determination of hydroquinone in medicated skin cosmetic cream

Impact of overexpressing NADH kinase on glucose and xylose metabolism in recombinant xylose-utilizing Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Hou, Jin; Vemuri, G. N.; Bao, X. M.

2009-01-01

of overexpressing the native NADH kinase (encoded by the POS5 gene) in xylose-consuming recombinant S. cerevisiae directed either into the cytosol or to the mitochondria was evaluated. The physiology of the NADH kinase containing strains was also evaluated during growth on glucose. Overexpressing NADH kinase...

NAD(H) and NADP(H) Redox Couples and Cellular Energy Metabolism.

Science.gov (United States)

Xiao, Wusheng; Wang, Rui-Sheng; Handy, Diane E; Loscalzo, Joseph

2018-01-20

The nicotinamide adenine dinucleotide (NAD + )/reduced NAD + (NADH) and NADP + /reduced NADP + (NADPH) redox couples are essential for maintaining cellular redox homeostasis and for modulating numerous biological events, including cellular metabolism. Deficiency or imbalance of these two redox couples has been associated with many pathological disorders. Recent Advances: Newly identified biosynthetic enzymes and newly developed genetically encoded biosensors enable us to understand better how cells maintain compartmentalized NAD(H) and NADP(H) pools. The concept of redox stress (oxidative and reductive stress) reflected by changes in NAD(H)/NADP(H) has increasingly gained attention. The emerging roles of NAD + -consuming proteins in regulating cellular redox and metabolic homeostasis are active research topics. The biosynthesis and distribution of cellular NAD(H) and NADP(H) are highly compartmentalized. It is critical to understand how cells maintain the steady levels of these redox couple pools to ensure their normal functions and simultaneously avoid inducing redox stress. In addition, it is essential to understand how NAD(H)- and NADP(H)-utilizing enzymes interact with other signaling pathways, such as those regulated by hypoxia-inducible factor, to maintain cellular redox homeostasis and energy metabolism. Additional studies are needed to investigate the inter-relationships among compartmentalized NAD(H)/NADP(H) pools and how these two dinucleotide redox couples collaboratively regulate cellular redox states and cellular metabolism under normal and pathological conditions. Furthermore, recent studies suggest the utility of using pharmacological interventions or nutrient-based bioactive NAD + precursors as therapeutic interventions for metabolic diseases. Thus, a better understanding of the cellular functions of NAD(H) and NADP(H) may facilitate efforts to address a host of pathological disorders effectively. Antioxid. Redox Signal. 28, 251-272.

Increased Production of Hydrogen Peroxide by Lactobacillus delbrueckii subsp. bulgaricus upon Aeration: Involvement of an NADH Oxidase in Oxidative Stress

Science.gov (United States)

Marty-Teysset, C.; de la Torre, F.; Garel, J.-R.

2000-01-01

The growth of Lactobacillus delbrueckii subsp. bulgaricus (L. delbrueckii subsp. bulgaricus) on lactose was altered upon aerating the cultures by agitation. Aeration caused the bacteria to enter early into stationary phase, thus reducing markedly the biomass production but without modifying the maximum growth rate. The early entry into stationary phase of aerated cultures was probably related to the accumulation of hydrogen peroxide in the medium. Indeed, the concentration of hydrogen peroxide in aerated cultures was two to three times higher than in unaerated ones. Also, a similar shift from exponential to stationary phase could be induced in unaerated cultures by adding increasing concentrations of hydrogen peroxide. A significant fraction of the hydrogen peroxide produced by L. delbrueckii subsp. bulgaricus originated from the reduction of molecular oxygen by NADH catalyzed by an NADH:H2O2 oxidase. The specific activity of this NADH oxidase was the same in aerated and unaerated cultures, suggesting that the amount of this enzyme was not directly regulated by oxygen. Aeration did not change the homolactic character of lactose fermentation by L. delbrueckii subsp. bulgaricus and most of the NADH was reoxidized by lactate dehydrogenase with pyruvate. This indicated that NADH oxidase had no (or a very small) energetic role and could be involved in eliminating oxygen. PMID:10618234

Imaging the NADH:NAD+ Homeostasis for Understanding the Metabolic Response of Mycobacterium to Physiologically Relevant Stresses.

Science.gov (United States)

Bhat, Shabir A; Iqbal, Iram K; Kumar, Ashwani

2016-01-01

The NADH:NAD + ratio is the primary indicator of the metabolic state of bacteria. NAD(H) homeostasis is critical for Mycobacterium tuberculosis (Mtb) survival and is thus considered an important drug target, but the spatio-temporal measurements of NAD(H) remain a challenge. Genetically encoded fluorescent biosensors of the NADH:NAD + ratios were recently described, paving the way for investigations of the metabolic state of pathogens during infection. Here we have adapted the genetically encoded biosensor Peredox for measurement of the metabolic state of Mtb in vitro and during infection of macrophage cells. Using Peredox, here we show that inhibition of the electron transport chain, disruption of the membrane potential and proton gradient, exposure to reactive oxygen species and treatment with antimycobacterial drugs led to the accumulation of NADH in mycobacterial cells. We have further demonstrated that Mtb residing in macrophages displays higher NADH:NAD + ratios, that may indicate a metabolic stress faced by the intracellular Mtb. We also demonstrate that the Mtb residing in macrophages display a metabolic heterogeneity, which may perhaps explain the tolerance displayed by intracellular Mtb. Next we studied the effect of immunological modulation by interferon gamma on metabolism of intracellular Mtb, since macrophage activation is known to restrict mycobacterial growth. We observed that activation of resting macrophages with interferon-gamma results in higher NADH:NAD + levels in resident Mtb cells. We have further demonstrated that exposure of Isoniazid, Bedaquiline, Rifampicin, and O-floxacin results in higher NADH:NAD + ratios in the Mtb residing in macrophages. However, intracellular Mtb displays lower NADH:NAD + ratio upon exposure to clofazimine. In summary, we have generated reporter strains capable of measuring the metabolic state of Mtb cells in vitro and in vivo with spatio-temporal resolution. We believe that this tool will facilitate further

Complementation of mitochondrial electron transport chain by manipulation of the NAD+/NADH ratio.

Science.gov (United States)

Titov, Denis V; Cracan, Valentin; Goodman, Russell P; Peng, Jun; Grabarek, Zenon; Mootha, Vamsi K

2016-04-08

A decline in electron transport chain (ETC) activity is associated with many human diseases. Although diminished mitochondrial adenosine triphosphate production is recognized as a source of pathology, the contribution of the associated reduction in the ratio of the amount of oxidized nicotinamide adenine dinucleotide (NAD(+)) to that of its reduced form (NADH) is less clear. We used a water-forming NADH oxidase from Lactobacillus brevis (LbNOX) as a genetic tool for inducing a compartment-specific increase of the NAD(+)/NADH ratio in human cells. We used LbNOX to demonstrate the dependence of key metabolic fluxes, gluconeogenesis, and signaling on the cytosolic or mitochondrial NAD(+)/NADH ratios. Expression of LbNOX in the cytosol or mitochondria ameliorated proliferative and metabolic defects caused by an impaired ETC. The results underscore the role of reductive stress in mitochondrial pathogenesis and demonstrate the utility of targeted LbNOX for direct, compartment-specific manipulation of redox state. Copyright © 2016, American Association for the Advancement of Science.

Surface enhanced Raman spectroscopy in the presence of hydroquinone assisted by gold nanorods

Science.gov (United States)

Cabrera Alonso, R.; Guevara, Edgar; Ramírez Elías, Miguel G.; González, Francisco Javier

2017-08-01

Hydroquinone is an aromatic organic molecule found in skin lightening creams for dermatological melasma treatment. The absorbance of this substance at high concentrations can be the cause of skin diseases. Nowadays most of the methods used for medical diagnosis for dermatological diseases consist on invasive methods such as biopsies. In recent years non-invasive techniques based on the properties of light and the interaction with biological samples have come to a new way for medical diagnosis. By means of Raman spectroscopy is of great interest the detection of hydroquinone for future medical applications. Due to the low Raman signal that the biological samples present, it is necessary to make use of nanotechnology. Making biosensors (SERS substrates) that allow us to amplify the electromagnetic field for the biological Raman signals.

Neptunium redox behavior and sorption onto goethite and hematite in the presence of humic acids with different hydroquinone content

International Nuclear Information System (INIS)

Khasanova, A.B.; Kalmykov, St.N.; Perminova, I.V.; Clark, S.B.

2007-01-01

The effect of humic acids (HA) on neptunium redox behavior and sorption onto hematite, α-Fe 2 O 3 , and goethite, α-FeOOH, colloids was established in batch sorption experiments that were carried out in broad pH interval. The sorption isotherms were provided for two samples of HA: commercial sample of leonardite humic acid and its hydroquinone-enriched derivative obtained using formaldehyde copolycondensation. The distribution of Np fitted the distribution of hydroquinone-enriched HA at low pH values in case of both solids while the influence of parent HA on Np sorption was negligible. This is due to Np(V) reduction upon interaction with hydroquinone-enriched derivative having higher reducing capacity compared to the parent HA. The order of components addition was found to be significant for Np retention

PSII as an in vivo molecular catalyst for the production of energy rich hydroquinones - A new approach in renewable energy.

Science.gov (United States)

Das, Sai; Maiti, Soumen K

2018-03-01

One of the pertinent issues in the field of energy science today is the quest for an abundant source of hydrogen or hydrogen equivalents. In this study, phenyl-p-benzoquinone (pPBQ) has been used to generate a molecular store of hydrogen equivalents (phenyl-p-hydroquinone; pPBQH 2 ) from thein vivo splitting of water by photosystem II of the marine cyanobacterium Synechococcus elongatus BDU 70542. Using this technique, 10.8 μmol of pPBQH 2 per mg chlorophyll a can be extracted per minute, an efficiency that is orders of magnitude higher when compared to the techniques present in the current literature. Moreover, the photo-reduction process was stable when tested over longer periods of time. Addition of phenyl-p-benzoquinone on an intermittent basis resulted in the precipitation of phenyl-p-hydroquinone, obviating the need for costly downstream processing units for product recovery. Phenyl-p-hydroquinone so obtained is a molecular store of free energy preserved through the light driven photolysis of water and can be used as a cheap and a renewable source of hydrogen equivalents by employing transition metal catalysts or fuel cells with the concomitant regeneration of phenyl-p-benzoquinone. The cyclic nature of this technique makes it an ideal candidate to be utilized in mankind's transition from fossil fuels to solar fuels. Copyright © 2018 Elsevier B.V. All rights reserved.

Separate and combined effect of low doses of ionizing radiation and hydroquinone on humoral immune response in regional lymph nodes

International Nuclear Information System (INIS)

Sharetskij, A.N.; Surinov, B.P.; Abramova, M.R.

1994-01-01

The whole-body exposure of mice to 0.1 Gy γ-radiation resulted in stimulation of T-cell dependent humoral immune response in lymph nodes. At the same enhansement of succeptability of immunocompetent cells to damaging effect of hydroquinone was observed. Under irradiation with doses of 0.5 or 1 Gy which cause dose-dependent immunosupression, hydroquinone induced stimulation of antigene production

Characterization of vanadate-dependent NADH oxidation activity and isolation of yeast DNA which complements a class 1 vanadate resistance mutation

International Nuclear Information System (INIS)

Minasi, L.E.

1989-01-01

A vanadate-dependent NADH oxidation activity has been characterized in plasma membranes from the yeast S cerevisiae. NADH oxidation activity was maximally stimulated at pH 5.0 in phosphate buffer. NADH oxidation was not dependent on the concentration of plasma membranes. The vanadate-dependent NADH oxidation activity was abolished under anaerobic conditions and the concomitant uptake of oxygen occurred during NADH oxidation. The activity was inhibited by superoxide dismutase and stimulated by the presence of paraquat. These results indicate that the vanadate stimulation of NADH oxidation in yeast plasma membranes occurs as a result of the vanadate-dependent oxidation of NADH by superoxide, generated by a plasma membrane NADH oxidase. 51 V-NMR results indicated that a phosphate-vanadate anhydride was the stimulatory species in pH 5.0 and pH 7.0 phosphate buffer. Yeast DNA has been isolated which complements a class 1 vanadate resistance mutation

Determining the Extremes of the Cellular NAD(H) Level by Using an Escherichia coli NAD+-Auxotrophic Mutant ▿

Science.gov (United States)

Zhou, Yongjin; Wang, Lei; Yang, Fan; Lin, Xinping; Zhang, Sufang; Zhao, Zongbao K.

2011-01-01

NAD (NAD+) and its reduced form (NADH) are omnipresent cofactors in biological systems. However, it is difficult to determine the extremes of the cellular NAD(H) level in live cells because the NAD+ level is tightly controlled by a biosynthesis regulation mechanism. Here, we developed a strategy to determine the extreme NAD(H) levels in Escherichia coli cells that were genetically engineered to be NAD+ auxotrophic. First, we expressed the ntt4 gene encoding the NAD(H) transporter in the E. coli mutant YJE001, which had a deletion of the nadC gene responsible for NAD+ de novo biosynthesis, and we showed NTT4 conferred on the mutant strain better growth in the presence of exogenous NAD+. We then constructed the NAD+-auxotrophic mutant YJE003 by disrupting the essential gene nadE, which is responsible for the last step of NAD+ biosynthesis in cells harboring the ntt4 gene. The minimal NAD+ level was determined in M9 medium in proliferating YJE003 cells that were preloaded with NAD+, while the maximal NAD(H) level was determined by exposing the cells to high concentrations of exogenous NAD(H). Compared with supplementation of NADH, cells grew faster and had a higher intracellular NAD(H) level when NAD+ was fed. The intracellular NAD(H) level increased with the increase of exogenous NAD+ concentration, until it reached a plateau. Thus, a minimal NAD(H) level of 0.039 mM and a maximum of 8.49 mM were determined, which were 0.044× and 9.6× those of wild-type cells, respectively. Finally, the potential application of this strategy in biotechnology is briefly discussed. PMID:21742902

Gene cloning and characterization of NADH oxidase from ...

African Journals Online (AJOL)

use

2011-12-07

Dec 7, 2011 ... potent inhibitors of NADH oxidases, silver nitrate and potassium cyanide did not show any significant ... anaerobes, a class of organisms that have not been ... DNA and amino acid sequence analyses were performed using.

Redox-flexible NADH oxidase biosensor: A platform for various dehydrogenase bioassays and biosensors

International Nuclear Information System (INIS)

Serban, Simona; El Murr, Nabil

2006-01-01

A generic amperometric bioassay based on the enzymatic oxidation catalysed by the stable NADH oxidase (NAox) from Thermus thermophilus has been developed for NADH measurements. The NAox uses O 2 as its natural electron acceptor and produces H 2 O 2 in a two-electron process. Electrochemical and spectrophotometric experiments showed that the NAox used in this work, presents a very good activity towards its substrate and, in contrary to previously mentioned NADH oxidases, does not require the addition of any exogenous flavin cofactor neither to promote nor to maintain its activity. In addition, the NAox used also works with artificial electron acceptors like ferrocene derivatives. O 2 was successfully replaced by redox mediators such as hydroxymethyl ferrocene (FcCH 2 OH) for the regeneration of the active enzyme. Combining the NAox with the mediator and the horseradish peroxidase we developed an original, high sensitive 'redox-flexible' NADH amperometric bioassay working in a large window of applied potentials in both oxidation and reduction modes. The biosensor has a continuous and complementary linearity range permitting to measure NADH concentrations starting from 5 x 10 -6 M in reduction until 2 x 10 3 M in oxidation. This redox-flexibility allows choosing the applied potential in order to avoid electrochemical interferences. The association of the 'redox-flexible' concept with NADH dependent enzymes opens a novel strategy for dehydrogenases based bioassays and biosensors. The great number of dehydrogenases available makes the concept applicable for numerous substrates to analyse. Moreover it allows the development of a wide range of biosensors on the basis of a generic platform. This gives several advantages over the previous manufacturing techniques and offers a general and flexible scheme for the fabrication of biosensors presenting high sensitivities, wide calibration ranges and less affected by electrochemical interferences

Identification of mitochondrial electron transport chain-mediated NADH radical formation by EPR spin-trapping techniques.

Science.gov (United States)

Matsuzaki, Satoshi; Kotake, Yashige; Humphries, Kenneth M

2011-12-20

The mitochondrial electron transport chain (ETC) is a major source of free radical production. However, due to the highly reactive nature of radical species and their short lifetimes, accurate detection and identification of these molecules in biological systems is challenging. The aim of this investigation was to determine the free radical species produced from the mitochondrial ETC by utilizing EPR spin-trapping techniques and the recently commercialized spin-trap, 5-(2,2-dimethyl-1,3-propoxycyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO). We demonstrate that this spin-trap has the preferential quality of having minimal mitochondrial toxicity at concentrations required for radical detection. In rat heart mitochondria and submitochondrial particles supplied with NADH, the major species detected under physiological pH was a carbon-centered radical adduct, indicated by markedly large hyperfine coupling constant with hydrogen (a(H) > 2.0 mT). In the presence of the ETC inhibitors, the carbon-centered radical formation was increased and exhibited NADH concentration dependency. The same carbon-centered radical could also be produced with the NAD biosynthesis precursor, nicotinamide mononucleotide, in the presence of a catalytic amount of NADH. The results support the conclusion that the observed species is a complex I derived NADH radical. The formation of the NADH radical could be blocked by hydroxyl radical scavengers but not SOD. In vitro experiments confirmed that an NADH-radical is readily formed by hydroxyl radical but not superoxide anion, further implicating hydroxyl radical as an upstream mediator of NADH radical production. These findings demonstrate the identification of a novel mitochondrial radical species with potential physiological significance and highlight the diverse mechanisms and sites of production within the ETC.

It's about time : investing in transportation to keep Texas economically competitive.

Science.gov (United States)

2011-03-01

This current report, It's About Time: Investing in Transportation to Keep Texas : Economically Competitive, updates the February 2009 report by providing : an enhanced analysis of the current state of the Texas transportation system, : determining th...

Determining the Extremes of the Cellular NAD(H) Level by Using an Escherichia coli NAD+-Auxotrophic Mutant ▿

OpenAIRE

Zhou, Yongjin; Wang, Lei; Yang, Fan; Lin, Xinping; Zhang, Sufang; Zhao, Zongbao K.

2011-01-01

NAD (NAD+) and its reduced form (NADH) are omnipresent cofactors in biological systems. However, it is difficult to determine the extremes of the cellular NAD(H) level in live cells because the NAD+ level is tightly controlled by a biosynthesis regulation mechanism. Here, we developed a strategy to determine the extreme NAD(H) levels in Escherichia coli cells that were genetically engineered to be NAD+ auxotrophic. First, we expressed the ntt4 gene encoding the NAD(H) transporter in the E. co...

Single sample extraction and HPLC processing for quantification of NAD and NADH levels in Saccharomyces cerevisiae

Energy Technology Data Exchange (ETDEWEB)

Sporty, J; Kabir, M M; Turteltaub, K; Ognibene, T; Lin, S; Bench, G

2008-01-10

A robust redox extraction protocol for quantitative and reproducible metabolite isolation and recovery has been developed for simultaneous measurement of nicotinamide adenine dinucleotide (NAD) and its reduced form, NADH, from Saccharomyces cerevisiae. Following culture in liquid media, approximately 10{sup 8} yeast cells were harvested by centrifugation and then lysed under non-oxidizing conditions by bead blasting in ice-cold, nitrogen-saturated 50-mM ammonium acetate. To enable protein denaturation, ice cold nitrogen-saturated CH{sub 3}CN + 50-mM ammonium acetate (3:1; v:v) was added to the cell lysates. After sample centrifugation to pellet precipitated proteins, organic solvent removal was performed on supernatants by chloroform extraction. The remaining aqueous phase was dried and resuspended in 50-mM ammonium acetate. NAD and NADH were separated by HPLC and quantified using UV-VIS absorbance detection. Applicability of this procedure for quantifying NAD and NADH levels was evaluated by culturing yeast under normal (2% glucose) and calorie restricted (0.5% glucose) conditions. NAD and NADH contents are similar to previously reported levels in yeast obtained using enzymatic assays performed separately on acid (for NAD) and alkali (for NADH) extracts. Results demonstrate that it is possible to perform a single preparation to reliably and robustly quantitate both NAD and NADH contents in the same sample. Robustness of the protocol suggests it will be (1) applicable to quantification of these metabolites in mammalian and bacterial cell cultures; and (2) amenable to isotope labeling strategies to determine the relative contribution of specific metabolic pathways to total NAD and NADH levels in cell cultures.

Synthesis of reduced carbon nitride at the reduction by hydroquinone of water-soluble carbon nitride oxide (g-C{sub 3}N{sub 4})O

Energy Technology Data Exchange (ETDEWEB)

Kharlamov, Alexey [Frantsevich Institute for Problems of Materials Science of NASU, Krzhyzhanovsky St. 3, 03680 Kiev (Ukraine); Bondarenko, Marina, E-mail: mebondarenko@ukr.net [Frantsevich Institute for Problems of Materials Science of NASU, Krzhyzhanovsky St. 3, 03680 Kiev (Ukraine); Kharlamova, Ganna [Taras Shevchenko National University of Kiev, Volodymyrs' ka St. 64, 01601 Kiev (Ukraine); Fomenko, Veniamin [Frantsevich Institute for Problems of Materials Science of NASU, Krzhyzhanovsky St. 3, 03680 Kiev (Ukraine)

2016-09-15

For the first time at the reduction by hydroquinone of water-soluble carbon nitride oxide (g-C{sub 3}N{sub 4})O reduced carbon nitride (or reduced multi-layer azagraphene) is obtained. It is differed from usually synthesized carbon nitride by a significantly large (on 0.09 nm) interplanar distance is. At the same time, the chemical bonds between atoms in a heteroatomic plane of reduced carbon nitride correspond to the bonds in a synthesized g-C{sub 3}N{sub 4}. The samples of water-soluble carbon nitride oxide were synthesized under the special reactionary conditions of a pyrolysis of melamine and urea. We believe that reduced carbon nitride consists of weakly connected carbon-nitrogen monosheets (azagraphene sheets) as well as reduced (from graphene oxide) graphene contains weakly connected graphene sheets. - Graphical abstract: XRD pattern and schematic atomic model of one layer of reduced carbon nitride, carbon nitride oxide and synthesized carbon nitride. For the first time at the reduction by hydroquinone of the water-soluble carbon nitride oxide (g-C{sub 3}N{sub 4})O is obtained the reduced carbon nitride (or reduced multi-layer azagraphene). Display Omitted - Highlights: • First the reduced carbon nitride (RCN) at the reduction of the carbon nitride oxide was obtained. • Water-soluble carbon nitride oxide was reduced by hydroquinone. • The chemical bonds in a heteroatomic plane of RCN correspond to the bonds in a synthesized g-C{sub 3}N{sub 4}. • Reduced carbon nitride consists of poorly connected heteroatomic azagraphene layers.

Intracellular Redox State Revealed by In Vivo 31P MRS Measurement of NAD+ and NADH Contents in Brains

Science.gov (United States)

Lu, Ming; Zhu, Xiao-Hong; Zhang, Yi; Chen, Wei

2015-01-01

Purpose Nicotinamide adenine dinucleotide (NAD), in oxidized (NAD+) or reduced (NADH) form, plays key roles in cellular metabolism. Intracellular NAD+/NADH ratio represents the cellular redox state; however, it is difficult to measure in vivo. We report here a novel in vivo 31P MRS method for noninvasive measurement of intracellular NAD concentrations and NAD+/NADH ratio in the brain. Methods It uses a theoretical model to describe the NAD spectral patterns at a given field for quantification. Standard NAD solutions and independent cat brain measurements at 9.4 T and 16.4 T were used to evaluate this method. We also measured T1 values of brain NAD. Results Model simulation and studies of solutions and brains indicate that the proposed method can quantify submillimolar NAD concentrations with reasonable accuracy if adequate 31P MRS signal-to-noise ratio and linewidth were obtained. The NAD concentrations and NAD+/NADH ratio of cat brains measured at 16.4 T and 9.4 T were consistent despite the significantly different T1 values and NAD spectra patterns at two fields. Conclusion This newly established 31P MRS method makes it possible for the first time to noninvasively study the intracellular redox state and its roles in brain functions and diseases, and it can potentially be applied to other organs. PMID:23843330

Cloning and mRNA Expression of NADH Dehydrogenase during Ochlerotatus taeniorhynchus Development and Pesticide Response

Science.gov (United States)

NADH dehydrogenase, the largest of the respiratory complexes, is the first enzyme of the mitochondrial electron transport chain. We have cloned and sequenced cDNA of NADH dehydrogenase gene from Ochlerotatus (Ochlerotatus) taeniorhynchus (Wiedemann) adult (GeneBank Accession number: FJ458415). The ...

Apoptosis-inducing Factor (AIF) and Its Family Member Protein, AMID, Are Rotenone-sensitive NADH:Ubiquinone Oxidoreductases (NDH-2)*

Science.gov (United States)

Elguindy, Mahmoud M.; Nakamaru-Ogiso, Eiko

2015-01-01

Apoptosis-inducing factor (AIF) and AMID (AIF-homologous mitochondrion-associated inducer of death) are flavoproteins. Although AIF was originally discovered as a caspase-independent cell death effector, bioenergetic roles of AIF, particularly relating to complex I functions, have since emerged. However, the role of AIF in mitochondrial respiration and redox metabolism has remained unknown. Here, we investigated the redox properties of human AIF and AMID by comparing them with yeast Ndi1, a type 2 NADH:ubiquinone oxidoreductase (NDH-2) regarded as alternative complex I. Isolated AIF and AMID containing naturally incorporated FAD displayed no NADH oxidase activities. However, after reconstituting isolated AIF or AMID into bacterial or mitochondrial membranes, N-terminally tagged AIF and AMID displayed substantial NADH:O2 activities and supported NADH-linked proton pumping activities in the host membranes almost as efficiently as Ndi1. NADH:ubiquinone-1 activities in the reconstituted membranes were highly sensitive to 2-n-heptyl-4-hydroxyquinoline-N-oxide (IC50 = ∼1 μm), a quinone-binding inhibitor. Overexpressing N-terminally tagged AIF and AMID enhanced the growth of a double knock-out Escherichia coli strain lacking complex I and NDH-2. In contrast, C-terminally tagged AIF and NADH-binding site mutants of N-terminally tagged AIF and AMID failed to show both NADH:O2 activity and the growth-enhancing effect. The disease mutant AIFΔR201 showed decreased NADH:O2 activity and growth-enhancing effect. Furthermore, we surprisingly found that the redox activities of N-terminally tagged AIF and AMID were sensitive to rotenone, a well known complex I inhibitor. We propose that AIF and AMID are previously unidentified mammalian NDH-2 enzymes, whose bioenergetic function could be supplemental NADH oxidation in cells. PMID:26063804

Apoptosis-inducing Factor (AIF) and Its Family Member Protein, AMID, Are Rotenone-sensitive NADH:Ubiquinone Oxidoreductases (NDH-2).

Science.gov (United States)

Elguindy, Mahmoud M; Nakamaru-Ogiso, Eiko

2015-08-21

Apoptosis-inducing factor (AIF) and AMID (AIF-homologous mitochondrion-associated inducer of death) are flavoproteins. Although AIF was originally discovered as a caspase-independent cell death effector, bioenergetic roles of AIF, particularly relating to complex I functions, have since emerged. However, the role of AIF in mitochondrial respiration and redox metabolism has remained unknown. Here, we investigated the redox properties of human AIF and AMID by comparing them with yeast Ndi1, a type 2 NADH:ubiquinone oxidoreductase (NDH-2) regarded as alternative complex I. Isolated AIF and AMID containing naturally incorporated FAD displayed no NADH oxidase activities. However, after reconstituting isolated AIF or AMID into bacterial or mitochondrial membranes, N-terminally tagged AIF and AMID displayed substantial NADH:O₂ activities and supported NADH-linked proton pumping activities in the host membranes almost as efficiently as Ndi1. NADH:ubiquinone-1 activities in the reconstituted membranes were highly sensitive to 2-n-heptyl-4-hydroxyquinoline-N-oxide (IC₅₀ = ∼1 μm), a quinone-binding inhibitor. Overexpressing N-terminally tagged AIF and AMID enhanced the growth of a double knock-out Escherichia coli strain lacking complex I and NDH-2. In contrast, C-terminally tagged AIF and NADH-binding site mutants of N-terminally tagged AIF and AMID failed to show both NADH:O₂ activity and the growth-enhancing effect. The disease mutant AIFΔR201 showed decreased NADH:O₂ activity and growth-enhancing effect. Furthermore, we surprisingly found that the redox activities of N-terminally tagged AIF and AMID were sensitive to rotenone, a well known complex I inhibitor. We propose that AIF and AMID are previously unidentified mammalian NDH-2 enzymes, whose bioenergetic function could be supplemental NADH oxidation in cells. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

The free NADH concentration is kept constant in plant mitochondria under different metabolic conditions

DEFF Research Database (Denmark)

Kasimova, M.R.; Grigiene, J.; Krab, K.

2006-01-01

with fluorescence spectroscopy. The NADH content of actively respiring mitochondria (from potato tubers [Solanum tuberosum cv Bintje]) in different metabolic states was then measured by spectral decomposition analysis of fluorescence emission spectra. Most of the mitochondrial NADH is bound to proteins...... metabolism. These findings have far-reaching consequences for the interpretation of cellular metabolism....

When hydroquinone meets methoxy radical: Hydrogen abstraction reaction from the viewpoint of interacting quantum atoms.

Science.gov (United States)

Petković, Milena; Nakarada, Đura; Etinski, Mihajlo

2018-05-25

Interacting Quantum Atoms methodology is used for a detailed analysis of hydrogen abstraction reaction from hydroquinone by methoxy radical. Two pathways are analyzed, which differ in the orientation of the reactants at the corresponding transition states. Although the discrepancy between the two barriers amounts to only 2 kJ/mol, which implies that the two pathways are of comparable probability, the extent of intra-atomic and inter-atomic energy changes differs considerably. We thus demonstrated that Interacting Quantum Atoms procedure can be applied to unravel distinct energy transfer routes in seemingly similar mechanisms. Identification of energy components with the greatest contribution to the variation of the overall energy (intra-atomic and inter-atomic terms that involve hydroquinone's oxygen and the carbon atom covalently bound to it, the transferring hydrogen and methoxy radical's oxygen), is performed using the Relative energy gradient method. Additionally, the Interacting Quantum Fragments approach shed light on the nature of dominant interactions among selected fragments: both Coulomb and exchange-correlation contributions are of comparable importance when considering interactions of the transferring hydrogen atom with all other atoms, whereas the exchange-correlation term dominates interaction between methoxy radical's methyl group and hydroquinone's aromatic ring. This study represents one of the first applications of Interacting Quantum Fragments approach on first order saddle points. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Radioprotection of DNA molecule by oxido-reduction's coenzymes

International Nuclear Information System (INIS)

Araos, M.S.; Fernandez, M.; Tomicic, I.; Toha, J.C.

1978-01-01

The radio protective action of respiratory coenzymes on DNA-water solutions is studied after irradiation with a 60 Co source. Coenzymes were used separately or in mixtures of their oxidized and reduced forms. The dose relative factor (DRF) values evaluated by uv absorbancy measurements of DNA damage were high: 18.03 for the (NAD-FAD-quinone) mixture (a respiratory chain model); 14.91 for (quinone-hydroquinone) mixtures; 14.46 for quinone; 14.27 for hydroquinone; 12.49 for FAD; 7.21 for the (NAD-NADH) mixture; 6.48 for NADH and 3.79 for NAD. No parallelism was found between the DNA coenzymes strong interactions and their protective action, performed by overcoming the indirect radiation damage. Besides, uv irradiation studies give no support to protection through direct energy transfer processes from excited DNA to coenzymes. The high efficiency of the mixtures of oxidized-reduced respiratory coenzymes is discussed in terms of simultaneous and equivalent trapping of recombinable radicals. The high tolerance of these protectors in living cells is emphasized. (author)

Gene cloning and characterization of NADH oxidase from ...

African Journals Online (AJOL)

The genome search of Thermococcus kodakarensis revealed three open reading frames, Tk0304, Tk1299 and Tk1392 annotated as nicotinamide adenine dinucleotide (NADH) oxidases. This study deals with cloning, and characterization of Tk0304. The gene, composed of 1320 nucleotides, encodes a protein of 439 ...

Overexpression of a water-forming NADH oxidase improves the metabolism and stress tolerance of Saccharmyces cerevisiae in aerobic fermenation

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Xinchi Shi

2016-09-01

Full Text Available Redox homeostasis is fundamental to the maintenance of metabolism. Redox imbalance can cause oxidative stress, which affects metabolism and growth. Water-forming NADH oxidase regulates the redox balance by oxidizing cytosolic NADH to NAD+, which relieves cytosolic NADH accumulation through rapid glucose consumption in Saccharomyces cerevisiae, thus decreasing the production of the byproduct glycerol in industrial ethanol production. Here, we studied the effects of overexpression of a water-forming NADH oxidase from Lactococcus lactis on the stress response of S. cerevisiae in aerobic batch fermentation, and we constructed an interaction network of transcriptional regulation and metabolic networks to study the effects of and mechanisms underlying NADH oxidase regulation. The oxidase-overexpressing strain (NOX showed increased glucose consumption, growth, and ethanol production, while glycerol production was remarkably lower. Glucose was exhausted by NOX at 26 h, while 18.92 ± 0.94 g/L residual glucose was left in the fermentation broth of the control strain (CON at this time point. At 29.5 h, the ethanol concentration for NOX peaked at 35.25 ± 1.76 g/L, which was 14.37 % higher than that for CON (30.82 ± 1.54 g/L. Gene expression involved in the synthesis of thiamine, which is associated with stress responses in various organisms, was increased in NOX. The transcription factor HAP4 was significantly upregulated in NOX at the late-exponential phase, indicating a diauxic shift in response to starvation. The apoptosis-inducing factor Nuc1 was downregulated while the transcription factor Sok2, which regulates the production of the small signaling molecule ammonia, was upregulated at the late-exponential phase, benefiting young cells on the rim. Reactive oxygen species production was decreased by 10% in NOX, supporting a decrease in apoptosis. The HOG pathway was not activated, although the osmotic stress was truly higher, indicating improved

Effect of Grafted Hydroquinone on the Acid-Base Properties of Poly(acrylic acid in the Presence of Copper (II

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Nabila Bensacia

2015-01-01

Full Text Available Potentiometric titration of poly(acrylic acid and hydroquinone-functionalized poly(acrylic acid was conducted in the presence of copper (II. The effects of hydroquinone functionalizing and copper (II complexing on the potentiometric titration of poly(acrylic acid were studied in an ionic environment and in its absence. Henderson-Hasselbalch equation was applied to assess its validity for this titration. Coordination number and the stability constants of the copper- (II-complexed polymers were determined, and results showed the formation of mostly monodentate and bidentate copper- (II-polymer complexes.

Investigation of the NADH/NAD+ ratio in Ralstonia eutropha using the fluorescence reporter protein Peredox.

Science.gov (United States)

Tejwani, Vijay; Schmitt, Franz-Josef; Wilkening, Svea; Zebger, Ingo; Horch, Marius; Lenz, Oliver; Friedrich, Thomas

2017-01-01

Ralstonia eutropha is a hydrogen-oxidizing ("Knallgas") bacterium that can easily switch between heterotrophic and autotrophic metabolism to thrive in aerobic and anaerobic environments. Its versatile metabolism makes R. eutropha an attractive host for biotechnological applications, including H 2 -driven production of biodegradable polymers and hydrocarbons. H 2 oxidation by R. eutropha takes place in the presence of O 2 and is mediated by four hydrogenases, which represent ideal model systems for both biohydrogen production and H 2 utilization. The so-called soluble hydrogenase (SH) couples reversibly H 2 oxidation with the reduction of NAD + to NADH and has already been applied successfully in vitro and in vivo for cofactor regeneration. Thus, the interaction of the SH with the cellular NADH/NAD + pool is of major interest. In this work, we applied the fluorescent biosensor Peredox to measure the [NADH]:[NAD + ] ratio in R. eutropha cells under different metabolic conditions. The results suggest that the sensor operates close to saturation level, indicating a rather high [NADH]:[NAD + ] ratio in aerobically grown R. eutropha cells. Furthermore, we demonstrate that multicomponent analysis of spectrally-resolved fluorescence lifetime data of the Peredox sensor response to different [NADH]:[NAD + ] ratios represents a novel and sensitive tool to determine the redox state of cells. Copyright © 2016 Elsevier B.V. All rights reserved.

Two-photon NADH imaging exposes boundaries of oxygen diffusion in cortical vascular supply regions.

Science.gov (United States)

Kasischke, Karl A; Lambert, Elton M; Panepento, Ben; Sun, Anita; Gelbard, Harris A; Burgess, Robert W; Foster, Thomas H; Nedergaard, Maiken

2011-01-01

Oxygen transport imposes a possible constraint on the brain's ability to sustain variable metabolic demands, but oxygen diffusion in the cerebral cortex has not yet been observed directly. We show that concurrent two-photon fluorescence imaging of endogenous nicotinamide adenine dinucleotide (NADH) and the cortical microcirculation exposes well-defined boundaries of tissue oxygen diffusion in the mouse cortex. The NADH fluorescence increases rapidly over a narrow, very low pO(2) range with a p(50) of 3.4 ± 0.6 mm Hg, thereby establishing a nearly binary reporter of significant, metabolically limiting hypoxia. The transient cortical tissue boundaries of NADH fluorescence exhibit remarkably delineated geometrical patterns, which define the limits of tissue oxygen diffusion from the cortical microcirculation and bear a striking resemblance to the ideal Krogh tissue cylinder. The visualization of microvessels and their regional contribution to oxygen delivery establishes penetrating arterioles as major oxygen sources in addition to the capillary network and confirms the existence of cortical oxygen fields with steep microregional oxygen gradients. Thus, two-photon NADH imaging can be applied to expose vascular supply regions and to localize functionally relevant microregional cortical hypoxia with micrometer spatial resolution.

Rotational barriers of 1,3-substitute pyridines and benzenes as models for the NAD+/NADH coenzyme

NARCIS (Netherlands)

Vanhommerig, S.A.M.; Meier, R.J.; Sluyterman, L.A.A.E.; Meijer, E.M.

1994-01-01

The NAD+/NADH coenzyme is involved in many enzyme-catalysed oxidation-reduction reactions. In order to obtain better insight in the catalytic mechanism of NAD+/NADH dependent dehydrogenases, conformational studies of 1,3-substituted pyridines and benzenes were carried out, using ab initio,

Nikkaji Dictionary: デアミノNADH [MeCab user dictionary for science technology term[Archive

Lifescience Database Archive (English)

Full Text Available MeCab user dictionary for science technology term デアミノNADH 名詞 一般 * * * * デアミノNADH ... Nikkaji J707.348H 200906099845094600 C CA06 UNKNOWN_2 デアミノ N AD H

Sources and implications of NADH/NAD+ redox imbalance in diabetes and its complications

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Wu J

2016-05-01

Full Text Available Jinzi Wu,1Zhen Jin,1Hong Zheng,1,2Liang-Jun Yan1 1Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA; 2Department of Basic Theory of Traditional Chinese Medicine, College of Basic Medicine, Shandong University of Traditional Chinese Medicine, Jinan, People’s Republic of China Abstract: NAD+ is a fundamental molecule in metabolism and redox signaling. In diabetes and its complications, the balance between NADH and NAD+ can be severely perturbed. On one hand, NADH is overproduced due to influx of hyperglycemia to the glycolytic and Krebs cycle pathways and activation of the polyol pathway. On the other hand, NAD+ can be diminished or depleted by overactivation of poly ADP ribose polymerase that uses NAD+ as its substrate. Moreover, sirtuins, another class of enzymes that also use NAD+ as their substrate for catalyzing protein deacetylation reactions, can also affect cellular content of NAD+. Impairment of NAD+ regeneration enzymes such as lactate dehydrogenase in erythrocytes and complex I in mitochondria can also contribute to NADH accumulation and NAD+ deficiency. The consequence of NADH/NAD+ redox imbalance is initially reductive stress that eventually leads to oxidative stress and oxidative damage to macromolecules, including DNA, lipids, and proteins. Accordingly, redox imbalance-triggered oxidative damage has been thought to be a major factor contributing to the development of diabetes and its complications. Future studies on restoring NADH/NAD+ redox balance could provide further insights into design of novel antidiabetic strategies. Keywords: mitochondria, complex I, reactive oxygen species, polyol pathway, poly ADP ribosylation, sirtuins, oxidative stress, oxidative damage

Self-assembly of graphitic carbon nitride nanosheets–carbon nanotube composite for electrochemical simultaneous determination of catechol and hydroquinone

International Nuclear Information System (INIS)

Zhang, Hanqiang; Huang, Yihong; Hu, Shirong; Huang, Qitong; Wei, Chan; Zhang, Wuxiang; Yang, Weize; Dong, Peihui; Hao, Aiyou

2015-01-01

Graphical abstract: Schematic diagram of hydrothermal synthesis graphitic carbon nitride nanosheets-carbon nanotube composite and theirs application for electrochemical sensing catechol and hydroquinone. - Highlights: • Self-assembly of graphitic carbon nitride nanosheets-carbon nanotube composite. • CNNS-CNT show more stronger conductivity than CNNS and CNT. • CNNS-CNT has been performed for detection of catechol and hydroquinone. • The probe was applied to detect practical samples with satisfactory results. - Abstract: In this paper, three-dimensional (3D) graphitic carbon nitride nanosheets-carbon nanotube (CNNS-CNT) composite was synthesized via hydrothermal reaction of 2D CNNS and 1D CNT-COOH by π-π stacking and electrostatic interactions. This CNNS-CNT composite was characterized by transmission electron microscope, scanning electron microscope, x-ray diffraction and fourier-transform infrared. In addition, the CNNS-CNT composite displayed excellent conductivity comparing with CNNS and CNT-COOH monomer. This composite was applied for electrochemical simultaneous determination of catechol (CC) and hydroquinone (HQ) with good sensitivity, wide linear range and low detection limit. In addition, this CNNS-CNT composite modified electrode was also applied to detect practical samples with satisfactory results

The effects of strawberry tree water leaf extract, arbutin and hydroquinone on haematological parameters and levels of primary DNA damage in white blood cells of rats.

Science.gov (United States)

Jurica, Karlo; Brčić Karačonji, Irena; Kopjar, Nevenka; Shek-Vugrovečki, Ana; Cikač, Tihana; Benković, Vesna

2018-04-06

Strawberry tree (Arbutus unedo L., Ericaceae) leaves represent a potent source of biologically active compounds and have been used for a long to relieve symptoms of various health impairments and diseases. Two major compounds related to their beneficial activities in animals and humans are arbutin and hydroquinone. To establish potential benefit/risk ratio associated with daily oral administration of strawberry tree water leaf extract, arbutin and hydroquinone in doses expected to be non-toxic. We performed a 14-day and a 28-day study on male and female Lewis rats and evaluated main haematological parameters and the effects of treatments on the levels of primary DNA damage in white blood cells (WBC) using the alkaline comet assay. Our findings suggest no significant changes in the haematological parameters following prolonged exposure to strawberry tree water leaf extract, arbutin, and hydroquinone. However, hydroquinone causes increased, and extract as well as arbutin decreased WBC count in male rats compared to control after 14 days of treatment. DNA damage measured in WBC of rats treated with all compounds was below 10% of the DNA in the comet tail, which indicates low genotoxicity. The genotoxic potential of strawberry water leaf extract was within acceptable limits and reflected effects of a complex chemical composition upon DNA. We also observed slight gender- and exposure time- related differences in primary DNA damage in the leucocytes of control and treated rats. Future studies should investigate which doses of strawberry tree water leaf extract would be most promising for the potential use as a substitute for bearberry leaves for treatment of urinary infection. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation and electrochemical application of rutin biosensor for differential pulse voltammetric determination of NADH in the presence of acetaminophen

Directory of Open Access Journals (Sweden)

HAMID R. ZARE

2010-10-01

Full Text Available The electrocatalytic behavior of reduced nicotinamide adenine di-nucleotide (NADH was studied at the surface of a rutin biosensor, using various electrochemical methods. According to the results, the rutin biosensor had a strongly electrocatalytic effect on the oxidation of NADH with the overpotential being decreased by about 450 mV as compared to the process at a bare glassy carbon electrode, GCE. This value is significantly greater than the value of 220 mV that was reported for rutin embedded in a lipid-cast film. The kinetic parameters of the electron transfer coefficient, a, and the heterogeneous charge transfer rate constant, kh, for the electrocatalytic oxidation of NADH at the rutin biosensor were estimated. Furthermore, the linear dynamic range; sensitivity and limit of detection for NADH were evaluated using the differential pulse voltammetry method. The advantages of this biosensor for the determination of NADH are excellent catalytic activity and reproducibility, good detection limit and high exchange current density. The rutin biosensor could separate the oxidation peak potentials of NADH and acetaminophen present in the same solution while at a bare GCE, the peak potentials were indistinguishable.

Characterization of water-forming NADH oxidases for co-factor regeneration

DEFF Research Database (Denmark)

Rehn, Gustav; Pedersen, Asbjørn Toftgaard; J. Charnock, Simon

an environmentaland economic perspective [1]. Alcohol dehydrogenases (ADH) offer one such alternative. However, the reaction requires the oxidized nicotinamide co-factor (NAD+) that must be recycled due to its high cost contribution. One regeneration method that offers certain advantages is the oxidation of NADH......Traditional chemical methods for alcohol oxidation are often associated with issues such as high consumption of expensive oxidizing agents, generation of metal waste and the use of environmentally undesirable organic solvents. Developing green, selective catalysts is therefore important from...... using water forming NADH oxidases (NOX-2). The implementation of the ADH/NOX system for alcohol oxidation, however, requires consideration of several different issues. Enzyme activity and stability at relevant pH and temperature conditions, but also the tolerance to the substrates and products present...

Two-photon NADH imaging exposes boundaries of oxygen diffusion in cortical vascular supply regions

OpenAIRE

Kasischke, Karl A; Lambert, Elton M; Panepento, Ben; Sun, Anita; Gelbard, Harris A; Burgess, Robert W; Foster, Thomas H; Nedergaard, Maiken

2010-01-01

Oxygen transport imposes a possible constraint on the brain's ability to sustain variable metabolic demands, but oxygen diffusion in the cerebral cortex has not yet been observed directly. We show that concurrent two-photon fluorescence imaging of endogenous nicotinamide adenine dinucleotide (NADH) and the cortical microcirculation exposes well-defined boundaries of tissue oxygen diffusion in the mouse cortex. The NADH fluorescence increases rapidly over a narrow, very low pO2 range with a p ...

Highly stable and reusable immobilized formate dehydrogenases: Promising biocatalysts for in situ regeneration of NADH

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Barış Binay

2016-02-01

Full Text Available This study aimed to prepare robust immobilized formate dehydrogenase (FDH preparations which can be used as effective biocatalysts along with functional oxidoreductases, in which in situ regeneration of NADH is required. For this purpose, Candida methylica FDH was covalently immobilized onto Immobead 150 support (FDHI150, Immobead 150 support modified with ethylenediamine and then activated with glutaraldehyde (FDHIGLU, and Immobead 150 support functionalized with aldehyde groups (FDHIALD. The highest immobilization yield and activity yield were obtained as 90% and 132%, respectively when Immobead 150 functionalized with aldehyde groups was used as support. The half-life times (t1/2 of free FDH, FDHI150, FDHIGLU and FDHIALD were calculated as 10.6, 28.9, 22.4 and 38.5 h, respectively at 35 °C. FDHI150, FDHIGLU and FDHIALD retained 69, 38 and 51% of their initial activities, respectively after 10 reuses. The results show that the FDHI150, FDHIGLU and FDHIALD offer feasible potentials for in situ regeneration of NADH.

Simple ortho- and para-hydroquinones as compounds neuroprotective against oxidative stress in a manner associated with specific transcriptional activation

International Nuclear Information System (INIS)

Satoh, Takumi; Saitoh, Sachie; Hosaka, Manami; Kosaka, Kunio

2009-01-01

Electrophilic compounds protect neurons through the activation of the Keap1/Nrf2 pathway and the induction of phase-2 enzymes [T. Satoh, S.A. Lipton, Redox regulation of neuronal survival by electrophilic compounds, Trends Neurosci. 30 (2007) 38-45; T. Satoh, S. Okamoto, J. Cui, Y. Watanabe, K. Furuta, M. Suzuki, K. Tohyama, S.A. Lipton, Activation of the Keap1/Nrf2 pathway for neuroprotection by electrophilic phase II inducers. Proc. Natl. Acad. Sci. USA 103 (2006) 768-773]. Hydroquinone-type electrophilic compounds such as tert-butyl hydroquinone (TBHQ) and carnosic acid (CA) have attracted special attention, because the oxidative conversion of 'hydroquinone' to 'quinone' is essential for the transcriptional activation of the above-mentioned enzymes [T. Satoh, K. Kosaka, K. Itoh, A. Kobayashi, M. Yamamoto, Y. Shimojo, C. Kitajima, J. Cui, J. Kamins, S. Okamoto, T. Shirasawa, S.A. Lipton, Carnosic acid, a catechol-type electrophilic compound, protect neurons both in vitro and in vivo through activation of the Keap1/Nrf2 pathway via S-alkylation of specific cysteine, J. Neurochem. 104 (2008) 1161-1131; A.D. Kraft, D.A. Johnson, J.A. Johnson, Nuclear factor E2-related factor 2-dependent antioxidant response element activation by tert-butylhydroquinone and sulforaphane occurring preferentially in astrocytes conditions neurons against oxidative insult, J. Neurosci. 24 (2004) 1101-1112]. In the present study, we examined the relationship between electrophilicity and the protective effects afforded by electrophilic compounds. Electrophilicity was assessed in terms of the ability of a compound to bind to a cysteine on bovine serum albumin, by which we found that neuroprotective hydroquinones [TBHQ (para-) and CA (ortho-)] had distinctive patterns of cysteine binding compared with other electrophilic compounds. Further, we found that isomers of simple ortho- and para-hydroquinones such as 2-methylhydroquinone (para-) and 4-methyl-catechol (ortho-) [not in abstract] had

Direct electrocatalytic reduction of coenzyme NAD{sup +} to enzymatically-active 1,4-NADH employing an iridium/ruthenium-oxide electrode

Energy Technology Data Exchange (ETDEWEB)

Ullah, Nehar, E-mail: nehar.ullah@mail.mcgill.ca; Ali, Irshad; Omanovic, Sasha

2015-01-15

A thermally prepared iridium/ruthenium-oxide coating (Ir{sub 0.8}Ru{sub 0.2}-oxide) formed on a titanium substrate was investigated as a possible electrode for direct electrochemical regeneration of enzymatically-active 1,4-NADH from its oxidized form NAD{sup +}, at various electrode potentials, in a batch electrochemical reactor. The coating surface was characterized by ‘cracked mud’ morphology, yielding a high surface roughness. The NADH regeneration results showed that the percentage of enzymatically-active 1,4-NADH present in the product mixture (i.e. recovery) is strongly dependent on the electrode potential, reaching a maximum (88%) at −1.70 V vs. MSE. The relatively high recovery was explained on the basis of availability of adsorbed ‘active’ hydrogen (H{sub ads}) on the Ir/Ru-oxide surface, i.e. on the basis of electrochemical hydrogenation. - Highlights: • Ir{sub 0.8}Ru{sub 0.2}-oxide coating was formed thermally on a Ti substrate. • Electrochemical regeneration of enzymatically-active 1,4-NADH was investigated. • The 1,4-NADH recovery percentage is strongly dependent on the electrode potential. • A highest recovery, 88%, was obtained at −1.70 V vs. MSE. • The NADH regeneration process involved electrochemical hydrogenation.

The Nitrite-Scavenging Properties of Catechol, Resorcinol, and Hydroquinone: A Comparative Study on Their Nitration and Nitrosation Reactions.

Science.gov (United States)

Lu, Yunhao; Dong, Yanzuo; Li, Xueli; He, Qiang

2016-10-14

The nitration and nitrosation reactions of catechol, resorcinol, and hydroquinone (0.05 mmol/L) with sodium nitrite (0.05 mmol/L) at pH 3 and 37 °C were studied by using liquid chromatography and mass spectrometry (LC-MS) and atom charge analysis, which was aimed to provide chemical insight into the nitrite-scavenging behavior of polyphenols. The 3 benzenediols showed different mechanisms to scavenge nitrite due to their differences in hydroxyl position. Catechol was nitrated with 1 NO 2 group at the hydroxyl oxygen, and resorcinol was nitrosated with 2 NO groups at the C 2 and C 4 (or C 6 ) positions of the benzene ring. Hydroquinone could scavenge nitrite through both nitration and nitrosation mechanisms. The nitrated hydroquinone had 1 NO 2 group at the hydroxyl oxygen in the molecule, while the nitrosated 1 containing 2 NO groups at the benzene ring might have 3 structure probabilities. The results may provide a structure-activity understanding on the nitrite-scavenging property of polyphenols, so as to promote their application in the food industry for the removal of possibly toxic nitrites found in many vegetables and often in processed meat products. © 2016 Institute of Food Technologists®.

The steady-state kinetics of the NADH-dependent nitrite reductase from Escherichia coli K 12. Nitrite and hydroxylamine reduction.

OpenAIRE

Jackson, R H; Cole, J A; Cornish-Bowden, A

1981-01-01

The reduction of both NO2- and hydroxylamine by the NADH-dependent nitrite reductase of Escherichia coli K 12 (EC 1.6.6.4) appears to follow Michaelis-Menten kinetics over a wide range of NADH concentrations. Substrate inhibition can, however, be detected at low concentrations of the product NAD+. In addition, NAD+ displays mixed product inhibition with respect to NADH and mixed or uncompetitive inhibition with respect to hydroxylamine. These inhibition characteristics are consistent with a m...

Involvement of NADH Oxidase in Biofilm Formation in Streptococcus sanguinis.

Directory of Open Access Journals (Sweden)

Xiuchun Ge

Full Text Available Biofilms play important roles in microbial communities and are related to infectious diseases. Here, we report direct evidence that a bacterial nox gene encoding NADH oxidase is involved in biofilm formation. A dramatic reduction in biofilm formation was observed in a Streptococcus sanguinis nox mutant under anaerobic conditions without any decrease in growth. The membrane fluidity of the mutant bacterial cells was found to be decreased and the fatty acid composition altered, with increased palmitic acid and decreased stearic acid and vaccenic acid. Extracellular DNA of the mutant was reduced in abundance and bacterial competence was suppressed. Gene expression analysis in the mutant identified two genes with altered expression, gtfP and Idh, which were found to be related to biofilm formation through examination of their deletion mutants. NADH oxidase-related metabolic pathways were analyzed, further clarifying the function of this enzyme in biofilm formation.

Improving methyl ketone production in Escherichia coli by heterologous expression of NADH-dependent FabG

DEFF Research Database (Denmark)

Goh, Ee Been; Chen, Yan; Petzold, Christopher J.

2018-01-01

balance, as fatty acid-derived pathways face the systematic metabolic challenge of net NADPH consumption (in large part, resulting from the key fatty acid biosynthetic enzyme FabG [β-ketoacyl-ACP reductase]) and net NADH production. In this study, we attempted to mitigate cofactor imbalance...... by heterologously expressing NADH-dependent, rather than NADPH-dependent, versions of FabG identified in previous studies. Of the four NADH-dependent versions of FabG tested in our previously best-reported methyl ketone-producing strain (EGS1895), the version from Acholeplasma laidlawii (Al_FabG) showed...... for the base strain (EGS1895) under fermentation conditions optimized in this study. Shotgun proteomic data for strains EGS2920 and EGS1895 during fed-batch fermentation were consistent with the goal of alleviating NADPH limitation through expression of Al_FabG. For example, relative to strain EGS1895, strain...

Electrochemistry in near-critical and supercritical fluids. 3. Studies of Br/sup -/, I/sup -/, and hydroquinone in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Flarsheim, W.J.; Tsou, Y.M.; Trachtenberg, I.; Johnston, K.P.; Bard, A.J.

1986-07-31

A new type of apparatus has been constructed for carrying out electrochemistry in near-critical and supercritical aqueous solutions. The following systems have been studied at a platinum electrode: H/sub 2/O/O/sub 2/, I/sup -//I/sub 2/, Br/sup -//Br/sub 2/, and hydroquinone/benzoquinone. The compact alumina flow cell can be heated or cooled quickly and can be recharged with fresh electrolyte solution while at high temperature and pressure. A large reduction in the potential required for the electrolysis of water was observed. Diffusivities have been measured for iodide ions and hydroquinone. General agreement with the Stokes-Einstein model was observed in the temperature range 25-375/sup 0/C.

Intracellular NAD(H) levels control motility and invasion of glioma cells.

NARCIS (Netherlands)

Horssen, R. van; Willemse, M.P.; Haeger, A.; Attanasio, F.; Guneri, T.; Schwab, A.; Stock, C.M.; Buccione, R.; Fransen, J.A.M.; Wieringa, B.

2013-01-01

Oncogenic transformation involves reprogramming of cell metabolism, whereby steady-state levels of intracellular NAD(+) and NADH can undergo dramatic changes while ATP concentration is generally well maintained. Altered expression of nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting

Time Keeping and Working Memory Development in Early Adolescence: A 4-Year Follow-Up

Science.gov (United States)

Forman, Helen; Mantyla, Timo; Carelli, Maria G.

2011-01-01

In this longitudinal study, we examined time keeping in relation to working memory (WM) development. School-aged children completed two tasks of WM updating and a time monitoring task in which they indicated the passing of time every 5 min while watching a film. Children completed these tasks first when they were 8 to 12 years old and then 4 years…

Investigating the Sensitivity of NAD+-dependent Sirtuin Deacylation Activities to NADH

DEFF Research Database (Denmark)

Madsen, Andreas Stahl; Andersen, Christian; Daoud, Mohammad Mahdi

2016-01-01

Protein lysine posttranslational modification by an increasing number of different acyl groups is becoming appreciated as a regulatory mechanism in cellular biology. Sirtuins are class III histone deacylases that use NAD+ as a co-substrate during amide bond hydrolysis. Several studies have...... described the sirtuins as sensors of the NAD+/NADH ratio, but it has not been formally tested for all the mammalian sirtuins in vitro. To address this problem, we first synthesized a wide variety of peptide-based probes, which were used to identify the range of hydrolytic activities of human sirtuins...... to be prone to hydrolytic cleavage by SIRT1-3 and SIRT6, supporting recent findings. We then tested the ability of NADH, ADP-ribose, and nicotinamide to inhibit these NAD+-dependent deacylase activities of the sirtuins. In the commonly used 7-amino-4-methylcoumarin-coupled fluorescence-based assay...

Coupled ferredoxin and crotonyl coenzyme A (CoA) reduction with NADH catalyzed by the butyryl-CoA dehydrogenase/Etf complex from Clostridium kluyveri.

Science.gov (United States)

Li, Fuli; Hinderberger, Julia; Seedorf, Henning; Zhang, Jin; Buckel, Wolfgang; Thauer, Rudolf K

2008-02-01

Cell extracts of butyrate-forming clostridia have been shown to catalyze acetyl-coenzyme A (acetyl-CoA)- and ferredoxin-dependent formation of H2 from NADH. It has been proposed that these bacteria contain an NADH:ferredoxin oxidoreductase which is allosterically regulated by acetyl-CoA. We report here that ferredoxin reduction with NADH in cell extracts from Clostridium kluyveri is catalyzed by the butyryl-CoA dehydrogenase/Etf complex and that the acetyl-CoA dependence previously observed is due to the fact that the cell extracts catalyze the reduction of acetyl-CoA with NADH via crotonyl-CoA to butyryl-CoA. The cytoplasmic butyryl-CoA dehydrogenase complex was purified and is shown to couple the endergonic reduction of ferredoxin (E0' = -410 mV) with NADH (E0' = -320 mV) to the exergonic reduction of crotonyl-CoA to butyryl-CoA (E0' = -10 mV) with NADH. The stoichiometry of the fully coupled reaction is extrapolated to be as follows: 2 NADH + 1 oxidized ferredoxin + 1 crotonyl-CoA = 2 NAD+ + 1 ferredoxin reduced by two electrons + 1 butyryl-CoA. The implications of this finding for the energy metabolism of butyrate-forming anaerobes are discussed in the accompanying paper.

Lambda Red-mediated mutagenesis and efficient large scale affinity purification of the Escherichia coli NADH:ubiquinone oxidoreductase (complex I).

Science.gov (United States)

Pohl, Thomas; Uhlmann, Mareike; Kaufenstein, Miriam; Friedrich, Thorsten

2007-09-18

The proton-pumping NADH:ubiquinone oxidoreductase, the respiratory complex I, couples the transfer of electrons from NADH to ubiquinone with the translocation of protons across the membrane. The Escherichia coli complex I consists of 13 different subunits named NuoA-N (from NADH:ubiquinone oxidoreductase), that are coded by the genes of the nuo-operon. Genetic manipulation of the operon is difficult due to its enormous size. The enzymatic activity of variants is obscured by an alternative NADH dehydrogenase, and purification of the variants is hampered by their instability. To overcome these problems the entire E. coli nuo-operon was cloned and placed under control of the l-arabinose inducible promoter ParaBAD. The exposed N-terminus of subunit NuoF was chosen for engineering the complex with a hexahistidine-tag by lambda-Red-mediated recombineering. Overproduction of the complex from this construct in a strain which is devoid of any membrane-bound NADH dehydrogenase led to the assembly of a catalytically active complex causing the entire NADH oxidase activity of the cytoplasmic membranes. After solubilization with dodecyl maltoside the engineered complex binds to a Ni2+-iminodiacetic acid matrix allowing the purification of approximately 11 mg of complex I from 25 g of cells. The preparation is pure and monodisperse and comprises all known subunits and cofactors. It contains more lipids than earlier preparations due to the gentle and fast purification procedure. After reconstitution in proteoliposomes it couples the electron transfer with proton translocation in an inhibitor sensitive manner, thus meeting all prerequisites for structural and functional studies.

Malate-aspartate shuttle and exogenous NADH/cytochrome c electron transport pathway as two independent cytosolic reducing equivalent transfer systems.

Science.gov (United States)

Abbrescia, Daniela Isabel; La Piana, Gianluigi; Lofrumento, Nicola Elio

2012-02-15

In mammalian cells aerobic oxidation of glucose requires reducing equivalents produced in glycolytic phase to be channelled into the phosphorylating respiratory chain for the reduction of molecular oxygen. Data never presented before show that the oxidation rate of exogenous NADH supported by the malate-aspartate shuttle system (reconstituted in vitro with isolated liver mitochondria) is comparable to the rate obtained on activation of the cytosolic NADH/cytochrome c electron transport pathway. The activities of these two reducing equivalent transport systems are independent of each other and additive. NADH oxidation induced by the malate-aspartate shuttle is inhibited by aminooxyacetate and by rotenone and/or antimycin A, two inhibitors of the respiratory chain, while the NADH/cytochrome c system remains insensitive to all of them. The two systems may simultaneously or mutually operate in the transfer of reducing equivalents from the cytosol to inside the mitochondria. In previous reports we suggested that the NADH/cytochrome c system is expected to be functioning in apoptotic cells characterized by the presence of cytochrome c in the cytosol. As additional new finding the activity of reconstituted shuttle system is linked to the amount of α-ketoglutarate generated inside the mitochondria by glutamate dehydrogenase rather than by aspartate aminotransferase. Copyright © 2011 Elsevier Inc. All rights reserved.

Determination of NAD⁺ and NADH level in a Single Cell Under H₂O₂ Stress by Capillary Electrophoresis

Energy Technology Data Exchange (ETDEWEB)

Xi, Wenjun [Iowa State Univ., Ames, IA (United States)

2008-01-01

A capillary electrophoresis (CE) method is developed to determine both NAD⁺ and NADH levels in a single cell, based on an enzymatic cycling reaction. The detection limit can reach down to 0.2 amol NAD⁺ and 1 amol NADH on a home-made CE-LIF setup. The method showed good reproducibility and specificity. After an intact cell was injected into the inlet of a capillary and lysed using a Tesla coil, intracellular NAD⁺ and NADH were separated, incubated with the cycling buffer, and quantified by the amount of fluorescent product generated. NADH and NAD⁺ levels of single cells of three cell lines and primary astrocyte culture were determined using this method. Comparing cellular NAD⁺ and NADH levels with and without exposure to oxidative stress induced by H₂O₂, it was found that H9c2 cells respond to the stress by reducing both cellular NAD⁺ and NADH levels, while astrocytes respond by increasing cellular NADH/NAD⁺ ratio.

Bioelectrocatalytic NAD+/NADH inter-conversion: transformation of an enzymatic fuel cell into an enzymatic redox flow battery.

Science.gov (United States)

Quah, Timothy; Milton, Ross D; Abdellaoui, Sofiene; Minteer, Shelley D

2017-07-25

Diaphorase and a benzylpropylviologen redox polymer were combined to create a bioelectrode that can both oxidize NADH and reduce NAD + . We demonstrate how bioelectrocatalytic NAD + /NADH inter-conversion can transform a glucose/O 2 enzymatic fuel cell (EFC) with an open circuit potential (OCP) of 1.1 V into an enzymatic redox flow battery (ERFB), which can be rapidly recharged by operation as an EFC.

Preferential inhibition of the plasma membrane NADH oxidase (NOX) activity by diphenyleneiodonium chloride with NADPH as donor

Science.gov (United States)

Morre, D. James

2002-01-01

The cell-surface NADH oxidase (NOX) protein of plant and animal cells will utilize both NADH and NADPH as reduced electron donors for activity. The two activities are distinguished by a differential inhibition by the redox inhibitor diphenyleneiodonium chloride (DPI). Using both plasma membranes and cells, activity with NADPH as donor was markedly inhibited by DPI at submicromolar concentrations, whereas with NADH as donor, DPI was much less effective or had no effect on the activity. The possibility of the inhibition being the result of two different enzymes was eliminated by the use of a recombinant NOX protein. The findings support the concept that NOX proteins serve as terminal oxidases for plasma membrane electron transport involving cytosolic reduced pyridine nucleotides as the natural electron donors and with molecular oxygen as the electron acceptor.

Activated barrier crossing dynamics in the non-radiative decay of NADH and NADPH

Energy Technology Data Exchange (ETDEWEB)

Blacker, Thomas S., E-mail: t.blacker@ucl.ac.uk [Centre for Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, London WC1E 6BT (United Kingdom); Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Research Department of Cell and Developmental Biology, University College London, London WC1E 6BT (United Kingdom); Marsh, Richard J., E-mail: richard.marsh@ucl.ac.uk [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Duchen, Michael R., E-mail: m.duchen@ucl.ac.uk [Research Department of Cell and Developmental Biology, University College London, London WC1E 6BT (United Kingdom); Bain, Angus J., E-mail: a.bain@ucl.ac.uk [Centre for Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, London WC1E 6BT (United Kingdom); Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom)

2013-08-30

Highlights: ► NADH and NADPH have a high rate of non-radiative excited state decay. ► Conformational relaxation is shown to be a significant non-radiative pathway. ► The Kramers equation describes the barrier crossing dynamics of the relaxation. ► Conformational restriction upon enzyme binding will alter NAD(P)H lifetimes. - Abstract: In live tissue, alterations in metabolism induce changes in the fluorescence decay of the biological coenzyme NAD(P)H, the mechanism of which is not well understood. In this work, the fluorescence and anisotropy decay dynamics of NADH and NADPH were investigated as a function of viscosity in a range of water–glycerol solutions. The viscosity dependence of the non-radiative decay is well described by Kramers and Kramers–Hubbard models of activated barrier crossing over a wide viscosity range. Our combined lifetime and anisotropy analysis indicates common mechanisms of non-radiative relaxation in the two emitting states (conformations) of both molecules. The low frequencies associated with barrier crossing suggest that non-radiative decay is mediated by small scale motion (e.g. puckering) of the nicotinamide ring. Variations in the fluorescence lifetimes of NADH and NADPH when bound to different enzymes may therefore be attributed to differing levels of conformational restriction upon binding.

The steady-state kinetics of the NADH-dependent nitrite reductase from Escherichia coli K 12. Nitrite and hydroxylamine reduction.

Science.gov (United States)

Jackson, R H; Cole, J A; Cornish-Bowden, A

1981-01-01

The reduction of both NO2- and hydroxylamine by the NADH-dependent nitrite reductase of Escherichia coli K 12 (EC 1.6.6.4) appears to follow Michaelis-Menten kinetics over a wide range of NADH concentrations. Substrate inhibition can, however, be detected at low concentrations of the product NAD+. In addition, NAD+ displays mixed product inhibition with respect to NADH and mixed or uncompetitive inhibition with respect to hydroxylamine. These inhibition characteristics are consistent with a mechanism in which hydroxylamine binds during catalysis to a different enzyme form from that generated when NAD+ is released. The apparent maximum velocity with NADH as varied substrate increases as the NAD+ concentration increases from 0.05 to 0.7 mM with 1 mM-NO2- or 100 mM-hydroxylamine as oxidized substrate. This increase is more marked for hydroxylamine reduction than for NO2- reduction. Models incorporating only one binding site for NAD can account for the variation in the Michaelis-Menten parameters for both NADH and hydroxylamine with [NAD+] for hydroxylamine reduction. According to these models, activation of the reaction occurs by reversal of an over-reduction of the enzyme by NADH. If the observed activation of the enzyme by NAD+ derives both from activation of the generation of the enzyme-hydroxylamine complex from the enzyme-NO2- complex during NO2- reduction and from activation of the reduction of the enzyme-hydroxylamine complex to form NH4+, then the variation of Vapp. for NO2- or hydroxylamine with [NAD+] is consistent with the occurrence of the same enzyme-hydroxylamine complex as an intermediate in both reactions. PMID:6279095

Quantitative fluorescence kinetic analysis of NADH and FAD in human plasma using three- and four-way calibration methods capable of providing the second-order advantage

Energy Technology Data Exchange (ETDEWEB)

Kang, Chao [School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025 (China); Wu, Hai-Long, E-mail: hlwu@hnu.edu.cn [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Zhou, Chang; Xiang, Shou-Xia; Zhang, Xiao-Hua; Yu, Yong-Jie; Yu, Ru-Qin [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

2016-03-03

The metabolic coenzymes reduced nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) are the primary electron donor and acceptor respectively, participate in almost all biological metabolic pathways. This study develops a novel method for the quantitative kinetic analysis of the degradation reaction of NADH and the formation reaction of FAD in human plasma containing an uncalibrated interferent, by using three-way calibration based on multi-way fluorescence technique. In the three-way analysis, by using the calibration set in a static manner, we directly predicted the concentrations of both analytes in the mixture at any time after the start of their reactions, even in the presence of an uncalibrated spectral interferent and a varying background interferent. The satisfactory quantitative results indicate that the proposed method allows one to directly monitor the concentration of each analyte in the mixture as the function of time in real-time and nondestructively, instead of determining the concentration after the analytical separation. Thereafter, we fitted the first-order rate law to their concentration data throughout their reactions. Additionally, a four-way calibration procedure is developed as an alternative for highly collinear systems. The results of the four-way analysis confirmed the results of the three-way analysis and revealed that both the degradation reaction of NADH and the formation reaction of FAD in human plasma fit the first-order rate law. The proposed methods could be expected to provide promising tools for simultaneous kinetic analysis of multiple reactions in complex systems in real-time and nondestructively. - Highlights: • A novel three-way calibration method for the quantitative kinetic analysis of NADH and FAD in human plasma is proposed. • The method can directly monitor the concentration of each analyte in the reaction in real-time and nondestructively. • The method has the second-order advantage. • A

Quantitative fluorescence kinetic analysis of NADH and FAD in human plasma using three- and four-way calibration methods capable of providing the second-order advantage

International Nuclear Information System (INIS)

Kang, Chao; Wu, Hai-Long; Zhou, Chang; Xiang, Shou-Xia; Zhang, Xiao-Hua; Yu, Yong-Jie; Yu, Ru-Qin

2016-01-01

The metabolic coenzymes reduced nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) are the primary electron donor and acceptor respectively, participate in almost all biological metabolic pathways. This study develops a novel method for the quantitative kinetic analysis of the degradation reaction of NADH and the formation reaction of FAD in human plasma containing an uncalibrated interferent, by using three-way calibration based on multi-way fluorescence technique. In the three-way analysis, by using the calibration set in a static manner, we directly predicted the concentrations of both analytes in the mixture at any time after the start of their reactions, even in the presence of an uncalibrated spectral interferent and a varying background interferent. The satisfactory quantitative results indicate that the proposed method allows one to directly monitor the concentration of each analyte in the mixture as the function of time in real-time and nondestructively, instead of determining the concentration after the analytical separation. Thereafter, we fitted the first-order rate law to their concentration data throughout their reactions. Additionally, a four-way calibration procedure is developed as an alternative for highly collinear systems. The results of the four-way analysis confirmed the results of the three-way analysis and revealed that both the degradation reaction of NADH and the formation reaction of FAD in human plasma fit the first-order rate law. The proposed methods could be expected to provide promising tools for simultaneous kinetic analysis of multiple reactions in complex systems in real-time and nondestructively. - Highlights: • A novel three-way calibration method for the quantitative kinetic analysis of NADH and FAD in human plasma is proposed. • The method can directly monitor the concentration of each analyte in the reaction in real-time and nondestructively. • The method has the second-order advantage. • A

Dual utilization of NADPH and NADH cofactors enhances xylitol production in engineered Saccharomyces cerevisiae.

Science.gov (United States)

Jo, Jung-Hyun; Oh, Sun-Young; Lee, Hyeun-Soo; Park, Yong-Cheol; Seo, Jin-Ho

2015-12-01

Xylitol, a natural sweetener, can be produced by hydrogenation of xylose in hemicelluloses. In microbial processes, utilization of only NADPH cofactor limited commercialization of xylitol biosynthesis. To overcome this drawback, Saccharomyces cerevisiae D452-2 was engineered to express two types of xylose reductase (XR) with either NADPH-dependence or NADH-preference. Engineered S. cerevisiae DWM expressing both the XRs exhibited higher xylitol productivity than the yeast strain expressing NADPH-dependent XR only (DWW) in both batch and glucose-limited fed-batch cultures. Furthermore, the coexpression of S. cerevisiae ZWF1 and ACS1 genes in the DWM strain increased intracellular concentrations of NADPH and NADH and improved maximum xylitol productivity by 17%, relative to that for the DWM strain. Finally, the optimized fed-batch fermentation of S. cerevisiae DWM-ZWF1-ACS1 resulted in 196.2 g/L xylitol concentration, 4.27 g/L h productivity and almost the theoretical yield. Expression of the two types of XR utilizing both NADPH and NADH is a promising strategy to meet the industrial demands for microbial xylitol production. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Coupled Ferredoxin and Crotonyl Coenzyme A (CoA) Reduction with NADH Catalyzed by the Butyryl-CoA Dehydrogenase/Etf Complex from Clostridium kluyveri▿ †

Science.gov (United States)

Li, Fuli; Hinderberger, Julia; Seedorf, Henning; Zhang, Jin; Buckel, Wolfgang; Thauer, Rudolf K.

2008-01-01

Cell extracts of butyrate-forming clostridia have been shown to catalyze acetyl-coenzyme A (acetyl-CoA)- and ferredoxin-dependent formation of H2 from NADH. It has been proposed that these bacteria contain an NADH:ferredoxin oxidoreductase which is allosterically regulated by acetyl-CoA. We report here that ferredoxin reduction with NADH in cell extracts from Clostridium kluyveri is catalyzed by the butyryl-CoA dehydrogenase/Etf complex and that the acetyl-CoA dependence previously observed is due to the fact that the cell extracts catalyze the reduction of acetyl-CoA with NADH via crotonyl-CoA to butyryl-CoA. The cytoplasmic butyryl-CoA dehydrogenase complex was purified and is shown to couple the endergonic reduction of ferredoxin (E0′ = −410 mV) with NADH (E0′ = −320 mV) to the exergonic reduction of crotonyl-CoA to butyryl-CoA (E0′ = −10 mV) with NADH. The stoichiometry of the fully coupled reaction is extrapolated to be as follows: 2 NADH + 1 oxidized ferredoxin + 1 crotonyl-CoA = 2 NAD+ + 1 ferredoxin reduced by two electrons + 1 butyryl-CoA. The implications of this finding for the energy metabolism of butyrate-forming anaerobes are discussed in the accompanying paper. PMID:17993531

Carbon nanofiber vs. carbon microparticles as modifiers of glassy carbon and gold electrodes applied in electrochemical sensing of NADH.

Science.gov (United States)

Pérez, Briza; Del Valle, Manel; Alegret, Salvador; Merkoçi, Arben

2007-12-15

Carbon materials (CMs), such as carbon nanotubes (CNTs), carbon nanofibers (CNFs), and carbon microparticles (CMPs) are used as doping materials for electrochemical sensors. The efficiency of these materials (either before or after acidic treatments) while being used as electrocatalysts in electrochemical sensors is discussed for beta-nicotinamide adenine dinucleotide (NADH) detection using cyclic voltammetry (CV). The sensitivity of the electrodes (glassy carbon (GC) and gold (Au)) modified with both treated and untreated materials have been deeply studied. The response efficiencies of the GC and Au electrodes modified with CNF and CMP, using dimethylformamide (DMF) as dispersing agent are significantly different due to the peculiar physical and chemical characteristics of each doping material. Several differences between the electrocatalytic activities of CMs modified electrodes upon NADH oxidation have been observed. The CNF film promotes better the electron transfer of NADH minimizing the oxidation potential at +0.352 V. Moreover higher currents for the NADH oxidation peak have been observed for these electrodes. The shown differences in the electrochemical reactivities of CNF and CMP modified electrodes should be with interest for future applications in biosensors.

A fiber-optic sorbitol biosensor based on NADH fluorescence detection toward rapid diagnosis of diabetic complications.

Science.gov (United States)

Gessei, Tomoko; Arakawa, Takahiro; Kudo, Hiroyuki; Mitsubayashi, Kohji

2015-09-21

Accumulation of sorbitol in the tissue is known to cause microvascular diabetic complications. In this paper, a fiber-optic biosensor for sorbitol which is used as a biomarker of diabetic complications was developed and tested. The biosensor used a sorbitol dehydrogenase from microorganisms of the genus Flavimonas with high substrate specificity and detected the fluorescence of reduced nicotinamide adenine dinucleotide (NADH) by the enzymatic reaction. An ultraviolet light emitting diode (UV-LED) was used as the excitation light source of NADH. The fluorescence of NADH was detected using a spectrometer or a photomultiplier tube (PMT). The UV-LED and the photodetector were coupled using a Y-shaped optical fiber. In the experiment, an optical fiber probe with a sorbitol dehydrogenase immobilized membrane was placed in a cuvette filled with a phosphate buffer containing the oxidized form of nicotinamide adenine dinucleotide (NAD(+)). The changes in NADH fluorescence intensity were measured after adding a standard sorbitol solution. According to the experimental assessment, the calibration range of the sorbitol biosensor systems using a spectrometer and a PMT was 5.0-1000 μmol L(-1) and 1.0-1000 μmol L(-1), respectively. The sorbitol biosensor system using the sorbitol dehydrogenase from microorganisms of the genus Flavimonas has high selectivity and sensitivity compared with that from sheep liver. The sorbitol biosensor allows for point-of-care testing applications or daily health care tests for diabetes patients.

Inhibitors of type II NADH:menaquinone oxidoreductase represent a class of antitubercular drugs

Science.gov (United States)

Weinstein, Edward A.; Yano, Takahiro; Li, Lin-Sheng; Avarbock, David; Avarbock, Andrew; Helm, Douglas; McColm, Andrew A.; Duncan, Ken; Lonsdale, John T.; Rubin, Harvey

2005-01-01

Mycobacterium tuberculosis (Mtb) is an obligate aerobe that is capable of long-term persistence under conditions of low oxygen tension. Analysis of the Mtb genome predicts the existence of a branched aerobic respiratory chain terminating in a cytochrome bd system and a cytochrome aa3 system. Both chains can be initiated with type II NADH:menaquinone oxidoreductase. We present a detailed biochemical characterization of the aerobic respiratory chains from Mtb and show that phenothiazine analogs specifically inhibit NADH:menaquinone oxidoreductase activity. The emergence of drug-resistant strains of Mtb has prompted a search for antimycobacterial agents. Several phenothiazines analogs are highly tuberculocidal in vitro, suppress Mtb growth in a mouse model of acute infection, and represent lead compounds that may give rise to a class of selective antibiotics. PMID:15767566

RATE AND CAPACITY OF HEPATIC MICROSOMAL RING HYDROXYLATION OF PHENOL TO HYDROQUINONE AND CATECHOL IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

Science.gov (United States)

Rainbow trout liver microsomes were used to study the rate of ring-hydroxylation of phenol (PH) by directly measuring the production of hydroquinone (HQ), the primary metabolite, and catechol (CAT), a secondary metabolite. An HPLC method with integrated ultroviolet (UV) and elect...

A novel strategy involved in [corrected] anti-oxidative defense: the conversion of NADH into NADPH by a metabolic network.

Directory of Open Access Journals (Sweden)

Ranji Singh

Full Text Available The reduced nicotinamide adenine dinucleotide phosphate (NADPH is pivotal to the cellular anti-oxidative defence strategies in most organisms. Although its production mediated by different enzyme systems has been relatively well-studied, metabolic networks dedicated to the biogenesis of NADPH have not been fully characterized. In this report, a metabolic pathway that promotes the conversion of reduced nicotinamide adenine dinucleotide (NADH, a pro-oxidant into NADPH has been uncovered in Pseudomonas fluorescens exposed to oxidative stress. Enzymes such as pyruvate carboxylase (PC, malic enzyme (ME, malate dehydrogenase (MDH, malate synthase (MS, and isocitrate lyase (ICL that are involved in disparate metabolic modules, converged to create a metabolic network aimed at the transformation of NADH into NADPH. The downregulation of phosphoenol carboxykinase (PEPCK and the upregulation of pyruvate kinase (PK ensured that this metabolic cycle fixed NADH into NADPH to combat the oxidative stress triggered by the menadione insult. This is the first demonstration of a metabolic network invoked to generate NADPH from NADH, a process that may be very effective in combating oxidative stress as the increase of an anti-oxidant is coupled to the decrease of a pro-oxidant.

Renewable Molecular Flasks with NADH Models: Combination of Light-Driven Proton Reduction and Biomimetic Hydrogenation of Benzoxazinones.

Science.gov (United States)

Zhao, Liang; Wei, Jianwei; Lu, Junhua; He, Cheng; Duan, Chunying

2017-07-17

Using small molecules with defined pockets to catalyze chemical transformations resulted in attractive catalytic syntheses that echo the remarkable properties of enzymes. By modulating the active site of a nicotinamide adenine dinucleotide (NADH) model in a redox-active molecular flask, we combined biomimetic hydrogenation with in situ regeneration of the active site in a one-pot transformation using light as a clean energy source. This molecular flask facilitates the encapsulation of benzoxazinones for biomimetic hydrogenation of the substrates within the inner space of the flask using the active sites of the NADH models. The redox-active metal centers provide an active hydrogen source by light-driven proton reduction outside the pocket, allowing the in situ regeneration of the NADH models under irradiation. This new synthetic platform, which offers control over the location of the redox events, provides a regenerating system that exhibits high selectivity and efficiency and is extendable to benzoxazinone and quinoxalinone systems. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthetic transformations of isoquinoline alkaloids. Synthesis of dihydrothebaine-hydroquinone derivatives

International Nuclear Information System (INIS)

Bauman, V.T.; Shul'ts, Eh. Eh.; Shakirov, M.M.; Tolstikov, G.A.

2007-01-01

Synthesis of new 6,14-endo-ethenodihydrothebaine-hydroquinone derivatives is carried through the introduction of iodine in molecule of the compound by means of iodine chloride or iodine in the presence of cerium-ammonium nitrate. 1-Iodine-5,14-endo-etheno-7,8-(1-acetoxy-4-hydroxybenzo)dihydrothebaine (yield 57%), 1-iodine-6,14-endo-etheno-7,8-(1,4-hydroquinono)dihydrothebaine (yield 13%) and 1-iodine-5'-chlorine-6,14-endo-etheno-7,8-(1,4-hydroquinono)dihydrothebaine (yield 11%) are separated as products of the reaction. Structure, molecular mass and element composition of iodination products were established on the basis of analysis of NMR spectra and mass spectroscopy, course of the reaction was controlled by TLC method [ru

How the visual brain encodes and keeps track of time.

Science.gov (United States)

Salvioni, Paolo; Murray, Micah M; Kalmbach, Lysiann; Bueti, Domenica

2013-07-24

Time is embedded in any sensory experience: the movements of a dance, the rhythm of a piece of music, the words of a speaker are all examples of temporally structured sensory events. In humans, if and how visual cortices perform temporal processing remains unclear. Here we show that both primary visual cortex (V1) and extrastriate area V5/MT are causally involved in encoding and keeping time in memory and that this involvement is independent from low-level visual processing. Most importantly we demonstrate that V1 and V5/MT come into play simultaneously and seem to be functionally linked during interval encoding, whereas they operate serially (V1 followed by V5/MT) and seem to be independent while maintaining temporal information in working memory. These data help to refine our knowledge of the functional properties of human visual cortex, highlighting the contribution and the temporal dynamics of V1 and V5/MT in the processing of the temporal aspects of visual information.

Hydroquinone and quinone-grafted porous carbons for highly selective CO2 capture from flue gases and natural gas upgrading

NARCIS (Netherlands)

Wang, J.; Krishna, R.; Yang, J.; Deng, S.

2015-01-01

Hydroquinone and quinone functional groups were grafted onto a hierarchical porous carbon framework via the Friedel-Crafts reaction to develop more efficient adsorbents for the selective capture and removal of carbon dioxide from flue gases and natural gas. The oxygen-doped porous carbons were

Kinetics and mechanism of reduction of iron(iii) kojic acid complex by hydroquinone and l-cysteine

International Nuclear Information System (INIS)

Hussain, Z.; Perviaz, M.; Kazmi, S.A.; Johnson, A.S.; Offiong, O.E.

2014-01-01

The effect of pH on the kinetics of reduction of iron(III) kojic acid complex by hydroquinone (H/sub 2/Q) and L-cysteine (L-Cys) was studied in the pH range of 2.34 - 4.03 for H/sub 2/Q and 3.04 - 5.5 for L-cysteine at ionic strength of 0.5 M and at 35 degree C. The pseudo-first order rate constants for the reduction of Fe(KA)3 by L-cysteine and hydroquinone increase linearly with increasing reductant concentration, indicating first-order kinetics in reductant concentration. However, whereas the rate of reduction by H2Q increases with increasing pH, an opposite trend was observed in the case of reduction by L-cysteine. Plausible rate laws and mechanisms have been proposed in line with these observations. Activation parameters (delta H no and delta S no) were evaluated for the reduction of iron (III) kojic acid complex by cysteine and the values obtained are 35.25 kJmol-1, -141.4 JK-1mol-1 and 28.14 kJmol-1 , 161.2 JK-1mol-1 for pH 4.5 and 3.52 respectively. (author)

Characterization of the type 2 NADH:menaquinone oxidoreductases from Staphylococcus aureus and the bactericidal action of phenothiazines.

Science.gov (United States)

Schurig-Briccio, Lici A; Yano, Takahiro; Rubin, Harvey; Gennis, Robert B

2014-07-01

Methicillin-resistant Staphylococcus aureus (MRSA) is currently one of the principal multiple drug resistant bacterial pathogens causing serious infections, many of which are life-threatening. Consequently, new therapeutic targets are required to combat such infections. In the current work, we explore the type 2 Nicotinamide adenine dinucleotide reduced form (NADH) dehydrogenases (NDH-2s) as possible drug targets and look at the effects of phenothiazines, known to inhibit NDH-2 from Mycobacterium tuberculosis. NDH-2s are monotopic membrane proteins that catalyze the transfer of electrons from NADH via flavin adenine dinucleotide (FAD) to the quinone pool. They are required for maintaining the NADH/Nicotinamide adenine dinucleotide (NAD(+)) redox balance and contribute indirectly to the generation of proton motive force. NDH-2s are not present in mammals, but are the only form of respiratory NADH dehydrogenase in several pathogens, including S. aureus. In this work, the two putative ndh genes present in the S. aureus genome were identified, cloned and expressed, and the proteins were purified and characterized. Phenothiazines were shown to inhibit both of the S. aureus NDH-2s with half maximal inhibitory concentration (IC50) values as low as 8μM. However, evaluating the effects of phenothiazines on whole cells of S. aureus was complicated by the fact that they are also acting as uncouplers of oxidative phosphorylation. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference. Copyright © 2014 Elsevier B.V. All rights reserved.

Several novel Ru(II) and Ru(III) complexes formed by reduction of (RuO4bipy) and (RuO3phen)2O with hydroquinone and methanol

International Nuclear Information System (INIS)

Ishiyama, Toshio

1975-01-01

The geometrical isomers, cis-dichloro-trans-(methanol)(hydroquinone)(2,2'-bipyridine)ruthenium(II) and cis-dichloro-cis-(methanol)(hydroquinone)(2,2'-bipyridine)ruthenium(II), [RuCl 2 (MeOH)(QH 2 )bipy] (complex I and II), were synthesized by reduction and substitution reactions of [RuO 4 bipy] and [RuO 2 (OH) 2 bipy] with hydroquinone in hydrochloric acid solution, and methanol. cis-Chloro(hydroquinonato)bis(2,2'-bipyridine)ruthenium(II), cis-[RuCl(QH)(bipy) 2 ], was obtained from the substitution reaction of complex I or II with 2,2'-bipyridine in methanol, and cis-chloro(hydroquinone)bis(2,2'-bipyridine)ruthenium(II) chloride, cis-[RuCl(QH 2 )(bipy) 2 ]Cl, was also obtained from the substitution of cis-trans-[RuCl 2 (MeOH)(QH 2 )bipy] in methanol containing hydrochloric acid. cis-Dihydroxobis(2,2'-bipyridine)ruthenium(II), cis-[Ru(OH) 2 (bipy) 2 ], was obtained by heating an aqueous solution of cis-[RuCl(QH)(bipy) 2 ]. Trihydroxoaquo(1,10-phenanthroline)ruthenium(III), [Ru(OH) 3 (H 2 O)phen] was also synthesized from [RuO 3 phen] 2 O and [Ru(OH) 3 phen] 2 O by reduction reactions similar to those used for [RuCl 2 (MeOH)(QH 2 )bipy]. These complexes were characterized by the infrared, visible and ultraviolet absorption spectra, and also by polarographic and magnetic measurements. The structures are discussed. (auth.)

Therapeutic Effects of Topical Tranexamic Acid in Comparison with Hydroquinone in Treatment of Women with Melasma.

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Atefi, Najmolsadat; Dalvand, Behzad; Ghassemi, Mahammadreza; Mehran, Golnaz; Heydarian, Amir

2017-09-01

Few studies have focused on therapeutic as well as side effects of tranexamic acid (TXA) as a topical drug compared to other topical drugs in treating melasma. The present study aimed to assess and compare the beneficial therapeutic effects and also side effects of local TXA in comparison with hydroquinone in treating women with melasma. This randomized double-blinded clinical trial was performed on 60 women who suffered from melasma and were referred to the skin disorders clinic at the Rasoul-e-Akram hospital in Tehran in 2015. The patients were then randomly assigned via computerized randomization to two groups: group A received TXA%5 (topically twice a day for 12 weeks in the location of the melasma) and group B (received hydroquinone 2% with the same treatment order). Prior to intervention and at 12 weeks after intervention, the intensity and extension of melasma were assessed based on the Melasma Area and Severity Index (MASI) scoring method. The mean MASI score in both treatment groups decreased considerably after completion of treatment and was not significant between the two groups. No side effects were detected in group A, but 10% of those in group B complained of drug-related side effects including erythema and skin irritation (p = 0.131). Regarding the level of patient satisfaction, the patients in group A had a significantly higher level of satisfaction level of 33.3% compared with 6.7% in group B (p = 0.015) (Fig. 9). Multivariate linear regression modeling with the presence of age, history of systemic disorder, drug history, and family history of melasma demonstrated no difference in the mean MASI between the two groups. Topical use of TXA significantly reduced both melanin level and MASI score. Given its high efficiency and low drug side effects, this regimen results in high patient satisfaction compared with topical hydroquinone. IRCT code: IRCT2016040627220N2.

Potential of Wood-Rotting Fungi to Attack Polystyrene Sulfonate and Its Depolymerisation by Gloeophyllum trabeum via Hydroquinone-Driven Fenton Chemistry.

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Martin C Krueger

Full Text Available Synthetic polymers often pose environmental hazards due to low biodegradation rates and resulting accumulation. In this study, a selection of wood-rotting fungi representing different lignocellulose decay types was screened for oxidative biodegradation of the polymer polystyrene sulfonate (PSS. Brown-rot basidiomycetes showed PSS depolymerisation of up to 50 % reduction in number-average molecular mass (Mn within 20 days. In-depth investigations with the most efficient depolymeriser, a Gloeophyllum trabeum strain, pointed at extracellular hydroquinone-driven Fenton chemistry responsible for depolymerisation. Detection of hydroxyl radicals present in the culture supernatants showed good compliance with depolymerisation over the time course of PSS degradation. 2,5-Dimethoxy-1,4-hydroquinone (2,5-DMHQ, which was detected in supernatants of active cultures via liquid chromatography and mass spectrometry, was demonstrated to drive the Fenton processes in G. trabeum cultures. Up to 80% reduction in Mn of PSS where observed when fungal cultures were additionally supplemented with 2,5-dimethoxy benzoquinone, the oxidized from of 2,5-DMHQ. Furthermore, 2,5-DMHQ could initiate the Fenton's reagent-mediated PSS depolymerisation in cell-free systems. In contrast, white-rot fungi were unable to cause substantial depolymerising effects despite the expression of lignin-modifying exo-enzymes. Detailed investigations with laccase from Trametes versicolor revealed that only in presence of certain redox mediators limited PSS depolymerisation occurred. Our results indicate that brown-rot fungi might be suitable organisms for the biodegradation of recalcitrant synthetic polymeric pollutants.

Improvement of exopolysaccharide production in Lactobacillus casei LC2W by overexpression of NADH oxidase gene.

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Li, Nan; Wang, Yuanlong; Zhu, Ping; Liu, Zhenmin; Guo, Benheng; Ren, Jing

2015-02-01

Lactobacillus casei LC2W is an exopolysaccharide (EPS)-producing strain with probiotic effects. To investigate the regulation mechanism of EPS biosynthesis and to improve EPS production through cofactor engineering, a H₂O-forming NADH oxidase gene was cloned from Streptococcus mutans and overexpressed in L. casei LC2W under the control of constitutive promoter P₂₃. The recombinant strain LC-nox exhibited 0.854 U/mL of NADH oxidase activity, which was elevated by almost 20-fold in comparison with that of wild-type strain. As a result, overexpression of NADH oxidase resulted in a reduction in growth rate. In addition, lactate production was decreased by 22% in recombinant strain. It was proposed that more carbon source was saved and used for the biosynthesis of EPS, the production of which was reached at 219.4 mg/L, increased by 46% compared to that of wild-type strain. This work provided a novel and convenient genetic approach to manipulate metabolic flux and to increase EPS production. To the best of our knowledge, this is the first report which correlates cofactor engineering with EPS production. Copyright © 2015 Elsevier GmbH. All rights reserved.

Chemiluminescence of graphene quantum dots induced by acidic potassium permanganate and its application to quenchometric flow-injection assays of hydroquinone in water

Energy Technology Data Exchange (ETDEWEB)

Su, Ming; Chen, Peiyun; Dong, Yajuan; Sun, Hanwen, E-mail: hanwen@hbu.edu.cn

2016-09-15

Graphene quantum dots (GQDs) with particle size of 4.5±1.0 nm were prepared and characterized by transmission electron microscopy, UV–vis absorption spectroscopy and fluorescence spectroscopy. It was found that KMnO{sub 4} could oxidize GQDs to produce a relatively intense chemiluminescence (CL) emission. The mechanism of CL generation was investigated based on absorption spectra and CL emission spectra. CL emission was attributed to the radiative recombination of oxidant-injected holes and thermally excited electrons in the GQDs. On the other hand, both KMnO{sub 4} and ∙O{sub 2}{sup −} could react with GQDs to produce GQDs∙{sup +} and GQDs∙{sup −}. The electron-transfer annihilation of GQDs∙{sup +} and GQDs∙{sup −} could form excited-state GQDs*, which acted as the final emitter in the system. In order to show the analytic potential of GQDs–KMnO{sub 4} CL system, it was applied for the determination of hydroquinone based on its diminishing effect. Under the optimized conditions, the proposed CL system exhibits excellent analytic performance for determination of hydroquinone. Calibration curve in the range of 2.49×10{sup −4}–9.96×10{sup −7} g mL{sup −1} was linear with the correlation coefficient (r) of 0.9924. The limit of detection was 8.46×10{sup −8} g mL{sup −1}, and the relative standard deviation (RSD) was found to be 1.7% for 11 determinations of 4.98×10{sup −6} g mL{sup −1} hydroquinone. The applicability of the method was verified by applying to real tap water, lake water, and waste water samples. The recoveries were in the range of 89.7–97.1% with RSD of 0.9–2.1%. The proposed method has a good linearity, high sensitivity and good repeatability and can be applied for routine determination of hydroquinone in water.

Determination of the in vivo NAD:NADH ratio in Saccharomyces cerevisiae under anaerobic conditions, using alcohol dehydrogenase as sensor reaction.

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Bekers, K M; Heijnen, J J; van Gulik, W M

2015-08-01

With the current quantitative metabolomics techniques, only whole-cell concentrations of NAD and NADH can be quantified. These measurements cannot provide information on the in vivo redox state of the cells, which is determined by the ratio of the free forms only. In this work we quantified free NAD:NADH ratios in yeast under anaerobic conditions, using alcohol dehydrogenase (ADH) and the lumped reaction of glyceraldehyde-3-phosphate dehydrogenase and 3-phosphoglycerate kinase as sensor reactions. We showed that, with an alternative accurate acetaldehyde determination method, based on rapid sampling, instantaneous derivatization with 2,4 diaminophenol hydrazine (DNPH) and quantification with HPLC, the ADH-catalysed oxidation of ethanol to acetaldehyde can be applied as a relatively fast and simple sensor reaction to quantify the free NAD:NADH ratio under anaerobic conditions. We evaluated the applicability of ADH as a sensor reaction in the yeast Saccharomyces cerevisiae, grown in anaerobic glucose-limited chemostats under steady-state and dynamic conditions. The results found in this study showed that the cytosolic redox status (NAD:NADH ratio) of yeast is at least one order of magnitude lower, and is thus much more reduced, under anaerobic conditions compared to aerobic glucose-limited steady-state conditions. The more reduced state of the cytosol under anaerobic conditions has major implications for (central) metabolism. Accurate determination of the free NAD:NADH ratio is therefore of importance for the unravelling of in vivo enzyme kinetics and to judge accurately the thermodynamic reversibility of each redox reaction. Copyright © 2015 John Wiley & Sons, Ltd.

New biotechnological perspectives of a NADH oxidase variant from Thermus thermophilus HB27 as NAD+-recycling enzyme

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Rocha-Martín Javier

2011-11-01

Full Text Available Abstract Background The number of biotransformations that use nicotinamide recycling systems is exponentially growing. For this reason one of the current challenges in biocatalysis is to develop and optimize more simple and efficient cofactor recycling systems. One promising approach to regenerate NAD+ pools is the use of NADH-oxidases that reduce oxygen to hydrogen peroxide while oxidizing NADH to NAD+. This class of enzymes may be applied to asymmetric reduction of prochiral substrates in order to obtain enantiopure compounds. Results The NADH-oxidase (NOX presented here is a flavoenzyme which needs exogenous FAD or FMN to reach its maximum velocity. Interestingly, this enzyme is 6-fold hyperactivated by incubation at high temperatures (80°C under limiting concentrations of flavin cofactor, a change that remains stable even at low temperatures (37°C. The hyperactivated form presented a high specific activity (37.5 U/mg at low temperatures despite isolation from a thermophile source. Immobilization of NOX onto agarose activated with glyoxyl groups yielded the most stable enzyme preparation (6-fold more stable than the hyperactivated soluble enzyme. The immobilized derivative was able to be reactivated under physiological conditions after inactivation by high solvent concentrations. The inactivation/reactivation cycle could be repeated at least three times, recovering full NOX activity in all cases after the reactivation step. This immobilized catalyst is presented as a recycling partner for a thermophile alcohol dehydrogenase in order to perform the kinetic resolution secondary alcohols. Conclusion We have designed, developed and characterized a heterogeneous and robust biocatalyst which has been used as recycling partner in the kinetic resolution of rac-1-phenylethanol. The high stability along with its capability to be reactivated makes this biocatalyst highly re-useable for cofactor recycling in redox biotransformations.

Acrolein inhibits NADH-linked mitochondrial enzyme activity: implications for Alzheimer's disease.

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Pocernich, Chava B; Butterfield, D Allan

2003-01-01

In Alzheimer's disease (AD) brain increased lipid peroxidation and decreased energy utilization are found. Mitochondria membranes contain a significant amount of arachidonic and linoleic acids, precursors of lipid peroxidation products, 4-hydroxynonenal (HNE) and 2-propen-1-al (acrolein), that are extremely reactive. Both alkenals are increased in AD brain. In this study, we examined the effects of nanomolar levels of acrolein on the activities of pyruvate dehydrogenase (PDH) and Alpha-ketoglutarate dehydrogenase (KGDH), both reduced nicotinamide adenine dinucleotide (NADH)-linked mitochondrial enzymes. Acrolein decreased PDH and KGDH activities significantly in a dose-dependent manner. Using high performance liquid chromatography coupled to mass spectrometry (HPLC-MS), acrolein was found to bind lipoic acid, a component in both the PDH and KGDH complexes, most likely explaining the loss of enzyme activity. Acrolein also interacted with oxidized nicotinamide adenine dinucleotide (NAD(+)) in such a way as to decrease the production of NADH. Acrolein, which is increased in AD brain, may be partially responsible for the dysfunction of mitochondria and loss of energy found in AD brain by inhibition of PDH and KGDH activities, potentially contributing to the neurodegeneration in this disorder.

Non-invasive in-cell determination of free cytosolic [NAD+]/[NADH] ratios using hyperpolarized glucose show large variations in metabolic phenotypes

DEFF Research Database (Denmark)

Christensen, Caspar Elo; Karlsson, Magnus; Winther, Jakob R.

2014-01-01

Accumulating evidence suggest that the pyridine nucleotide NAD has far wider biological functions than its classical role in energy metabolism. NAD is used by hundreds of enzymes that catalyse substrate oxidation and as such it plays a key role in various biological processes such as aging, cell...... death and oxidative stress. It has been suggested that changes in the ratio of free cytosolic [NAD+]/[NADH] reflects metabolic alterations leading to, or correlating with, pathological states. We have designed an isotopically labelled metabolic bioprobe of free cytosolic [NAD+]/[NADH] by combining...... a magnetic enhancement technique (hyperpolarization) with cellular glycolytic activity. The bioprobe reports free cytosolic [NAD+]/[NADH] ratios based on dynamically measured in-cell [pyruvate]/ [lactate] ratios. We demonstrate its utility in breast and prostate cancer cells. The free cytosolic [NAD...

Control of size and aspect ratio in hydroquinone-based synthesis of gold nanorods

International Nuclear Information System (INIS)

Morasso, Carlo; Picciolini, Silvia; Schiumarini, Domitilla; Mehn, Dora; Ojea-Jiménez, Isaac; Zanchetta, Giuliano; Vanna, Renzo; Bedoni, Marzia; Prosperi, Davide; Gramatica, Furio

2015-01-01

In this article, we describe how it is possible to tune the size and the aspect ratio of gold nanorods obtained using a highly efficient protocol based on the use of hydroquinone as a reducing agent by varying the amounts of CTAB and silver ions present in the “seed-growth” solution. Our approach not only allows us to prepare nanorods with a four times increased Au 3+ reduction yield, when compared with the commonly used protocol based on ascorbic acid, but also allows a remarkable reduction of 50–60 % of the amount of CTAB needed. In fact, according to our findings, the concentration of CTAB present in the seed-growth solution do not linearly influence the final aspect ratio of the obtained nanorods, and an optimal concentration range between 30 and 50 mM has been identified as the one that is able to generate particles with more elongated shapes. On the optimized protocol, the effect of the concentration of Ag + ions in the seed-growth solution and the stability of the obtained particles has also been investigated

Novel layered polyaniline-poly(hydroquinone)/graphene film as supercapacitor electrode with enhanced rate performance and cycling stability.

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Ren, Lijun; Zhang, Gaini; Lei, Ji; Wang, Yan; Hu, Dengwei

2018-02-15

It is a challenge to fabricate polyaniline (PANI) materials with high rate performance and excellent stability. Herein a new special supercapacitor electrode material of polyaniline-poly(hydroquinone)/graphene (PANI-PHQ/RGO) film with layered structure was prepared by chemical oxidative polymerization of aniline and hydroquinone (H 2 Q) in the presence of RGO hydrogel film. The synergistic effect and loose layered structure of the composite film facilitate fast diffusion and transportation of electrolyte ions through unimpeded channels during rapid charge-discharge process, resulting in high rate capability and stable cycling performance. As a result, the PANI-PHQ/RGO-61 film electrode exhibited 356 F g -1 at a current density of 0.5 A g -1 and high capacitance retention of 83% from 0.5 to 30 A g -1 . Moreover, it presented an excellent cycling stability with 94% of capacitance retention in comparison with 60% of pure PANI electrode and an outstanding Coulombic efficiency of 99% after 1000 cycles of galvanostatic charge-discharge. These superior electrocapacitive properties make it one of promising candidates for electrochemical energy storage. Copyright © 2017 Elsevier Inc. All rights reserved.

Hydroquinone: O-glucosyltransferase from cultivated Rauvolfia cells: enrichment and partial amino acid sequences.

Science.gov (United States)

Arend, J; Warzecha, H; Stöckigt, J

2000-01-01

Plant cell suspension cultures of Rauvolfia are able to produce a high amount of arbutin by glucosylation of exogenously added hydroquinone. A four step purification procedure using anion exchange, hydrophobic interaction, hydroxyapatite-chromatography and chromatofocusing delivered in a yield of 0.5%, an approximately 390 fold enrichment of the involved glucosyltransferase. SDS-PAGE showed a M(r) for the enzyme of 52 kDa. Proteolysis of the pure enzyme with endoproteinase LysC revealed six peptide fragments with 9-23 amino acids which were sequenced. Sequence alignment of the six peptides showed high homologies to glycosyltransferases from other higher plants.

Coulometric titrations of bases in propylene carbonate and g-butyrolactone using hydroquinone as the depolarizer and a quinhydrone indicator electrode

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Z. D. STANIC

2000-08-01

Full Text Available The application of hydroquinone for the coulometric generation of hydrogen ions in propylene carbonate (PC and g-butyrolactone (GBL is described. The current-potential curves recorded for theid sepolarizer, titrated bases, indicator and the solvents used showed that the investigated depolarizer is oxidized at lower potentials than the oxidation potentials of other components in the solution. the hydrogen ions generated by the oxidation of hydroquinone were used for the titration of organic bases (triethylamine, n-butylamine, pyridine, quinoline, aniline, N,N’-diphenylguanidine, piperidine, and 2,2’-bipiridine in PC and GBL with visual (Crystal Violet as indicator and potentiometric end-point detection using a quinhydrone electrode as the indicator electrode. The quinhydrone added to the to be analyzed solution served both as a source of hydrogen ions and, together with the immersed platinum electrode, as a quinhydrone electrode. The relative error of the determination of the bases was about 1 %.

Disruption of key NADH-binding pocket residues of the Mycobacterium tuberculosis InhA affects DD-CoA binding ability.

Science.gov (United States)

Shaw, Daniel J; Robb, Kirsty; Vetter, Beatrice V; Tong, Madeline; Molle, Virginie; Hunt, Neil T; Hoskisson, Paul A

2017-07-05

Tuberculosis (TB) is a global health problem that affects over 10 million people. There is an urgent need to develop novel antimicrobial therapies to combat TB. To achieve this, a thorough understanding of key validated drug targets is required. The enoyl reductase InhA, responsible for synthesis of essential mycolic acids in the mycobacterial cell wall, is the target for the frontline anti-TB drug isoniazid. To better understand the activity of this protein a series of mutants, targeted to the NADH co-factor binding pocket were created. Residues P193 and W222 comprise a series of hydrophobic residues surrounding the cofactor binding site and mutation of both residues negatively affect InhA function. Construction of an M155A mutant of InhA results in increased affinity for NADH and DD-CoA turnover but with a reduction in V max for DD-CoA, impairing overall activity. This suggests that NADH-binding geometry of InhA likely permits long-range interactions between residues in the NADH-binding pocket to facilitate substrate turnover in the DD-CoA binding region of the protein. Understanding the precise details of substrate binding and turnover in InhA and how this may affect protein-protein interactions may facilitate the development of improved inhibitors enabling the development of novel anti-TB drugs.

Factors influencing hydroquinone degradation in aqueous solution using a modified microelectrolysis method.

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Li, Tong; Li, Tingting; Xiong, Houfeng; Zou, Donglei

2015-01-01

The discharge of hydroquinone (HQ), an important chemical raw material, to natural waters poses different ecological threats to aquatic organisms. In this study, we investigated the removal performance of traditional and modified microelectrolysis methods in aqueous solutions. The traditional microelectrolysis packing was modified by adding manganese (Mn), zinc (Zn), and copper (Cu) powder as additives. The factors affecting the removal performance of HQ, such as catalytic metal type, mass fraction of additive, reaction time, and initial pH, were examined. The results showed that the Mn modified packing exhibited the best performance compared to Zn and Cu powder. The removal rate of HQ using Mn modified packing can reach 94% after 4 h. In addition, 9% of Mn packing has a higher removal rate than other mass fractions. The acidic solution pH shows a more favorable degradation than a neutral and alkaline solution. The intermediates of HQ degradation by modified microelectrolysis were identified and then the pathway of HQ degradation was proposed. Our result indicates that Mn as catalytic metal holds promising potential to enhance HQ removal in water using the microelectrolysis method.

Origin of attraction in p-benzoquinone complexes with benzene and p-hydroquinone.

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Tsuzuki, Seiji; Uchimaru, Tadafumi; Ono, Taizo

2017-08-30

The origin of the attraction in charge-transfer complexes (a p-hydroquinone-p-benzoquinone complex and benzene complexes with benzoquinone, tetracyanoethylene and Br 2 ) was analyzed using distributed multipole analysis and symmetry-adapted perturbation theory. Both methods show that the dispersion interactions are the primary source of the attraction in these charge-transfer complexes followed by the electrostatic interactions. The natures of the intermolecular interactions in these complexes are close to the π/π interactions of neutral aromatic molecules. The electrostatic interactions play important roles in determining the magnitude of the attraction. The contribution of charge-transfer interactions to the attraction is not large compared with the dispersion interactions in these complexes.

Mechanism of 3,4-dihydroxybenzaldehyde electropolymerization at carbon paste electrodes : catalytic detection of NADH

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Delbem Maria Flávia

2002-01-01

Full Text Available Cyclic voltammetry was used to study 3,4-dihydroxybenzaldehyde (3,4-DHB electropolymerization processes on carbon paste electrodes. The characteristics of the electropolymerized films were highly dependent on pH, anodic switching potential, scan rate, 3,4-DHB concentrations and number of cycles. Film stability was determined in citrate/phosphate buffer solutions at the same pH used during the electropolymerization process. The best conditions to prepare carbon paste modified electrodes were pH 7.8; 0.0 <= Eapl <= 0.25 V; 10 mV s-1; 0.25 mmol L-1 3,4-DHB and 10 scans. These carbon paste modified electrodes were used for NADH catalytic detection at 0.23 V in the range 0.015 <= [NADH] <= 0.21 mmol L-1. Experimental data were used to propose a mechanism for the 3,4--DHB electropolymerization processes, which involves initial phenoxyl radical formation.

In vivo imaging of cerebral energy metabolism with two-photon fluorescence lifetime microscopy of NADH.

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Yaseen, Mohammad A; Sakadžić, Sava; Wu, Weicheng; Becker, Wolfgang; Kasischke, Karl A; Boas, David A

2013-02-01

Minimally invasive, specific measurement of cellular energy metabolism is crucial for understanding cerebral pathophysiology. Here, we present high-resolution, in vivo observations of autofluorescence lifetime as a biomarker of cerebral energy metabolism in exposed rat cortices. We describe a customized two-photon imaging system with time correlated single photon counting detection and specialized software for modeling multiple-component fits of fluorescence decay and monitoring their transient behaviors. In vivo cerebral NADH fluorescence suggests the presence of four distinct components, which respond differently to brief periods of anoxia and likely indicate different enzymatic formulations. Individual components show potential as indicators of specific molecular pathways involved in oxidative metabolism.

Ethanol production from xylose by recombinant Saccharomyces cerevisiae expressing protein-engineered NADH-preferring xylose reductase from Pichia stipitis.

Science.gov (United States)

Watanabe, Seiya; Abu Saleh, Ahmed; Pack, Seung Pil; Annaluru, Narayana; Kodaki, Tsutomu; Makino, Keisuke

2007-09-01

A recombinant Saccharomyces cerevisiae strain transformed with xylose reductase (XR) and xylitol dehydrogenase (XDH) genes from Pichia stipitis (PsXR and PsXDH, respectively) has the ability to convert xylose to ethanol together with the unfavourable excretion of xylitol, which may be due to intercellular redox imbalance caused by the different coenzyme specificity between NADPH-preferring XR and NAD(+)-dependent XDH. In this study, we focused on the effect(s) of mutated NADH-preferring PsXR in fermentation. The R276H and K270R/N272D mutants were improved 52- and 146-fold, respectively, in the ratio of NADH/NADPH in catalytic efficiency [(k(cat)/K(m) with NADH)/(k(cat)/K(m) with NADPH)] compared with the wild-type (WT), which was due to decrease of k(cat) with NADPH in the R276H mutant and increase of K(m) with NADPH in the K270R/N272D mutant. Furthermore, R276H mutation led to significant thermostabilization in PsXR. The most positive effect on xylose fermentation to ethanol was found by using the Y-R276H strain, expressing PsXR R276H mutant and PsXDH WT: 20 % increase of ethanol production and 52 % decrease of xylitol excretion, compared with the Y-WT strain expressing PsXR WT and PsXDH WT. Measurement of intracellular coenzyme concentrations suggested that maintenance of the of NADPH/NADP(+) and NADH/NAD(+) ratios is important for efficient ethanol fermentation from xylose by recombinant S. cerevisiae.

Combined therapy using Q-switched ruby laser and bleaching treatment with tretinoin and hydroquinone for periorbital skin hyperpigmentation in Asians.

Science.gov (United States)

Momosawa, Akira; Kurita, Masakazu; Ozaki, Mine; Miyamoto, Shinpei; Kobayashi, Yo; Ban, Izumi; Harii, Kiyonori

2008-01-01

Periorbital skin hyperpigmentation, so-called dark circles, is of major concern for many people. However, only a few reports refer to the morbidity and treatment, and as far as the authors know, there are no reports of the condition in Asians. A total of 18 Japanese patients underwent combined therapy using Q-switched ruby laser to eliminate dermal pigmentation following topical bleaching treatment with tretinoin aqueous gel and hydroquinone ointment performed initially (6 weeks) to reduce epidermal melanin. Both steps were repeated two to four times until physical clearance of the pigmentation was confirmed and patient satisfaction was achieved. Skin biopsy was performed at baseline in each patient and at the end of treatment in three patients, all with informed consent. Clinical and histologic appearances of periorbital hyperpigmentation were evaluated and rated as excellent, good, fair, poor, or default. Seven of 18 patients (38.9 percent) showed excellent clearing after treatment and eight (44.4 percent) were rated good. Only one (5.6 percent) was rated fair and none was rated poor. Postinflammatory hyperpigmentation was observed in only two patients (11.1 percent). Histologic examination showed obvious epidermal hyperpigmentation in 10 specimens. Dermal pigmentation was observed in all specimens but was not considered to be melanocytosis. Remarkable reduction of dermal pigmentation was observed in the biopsy specimens of three patients after treatment. The new treatment protocol combining Q-switched ruby laser and topical bleaching treatment using tretinoin and hydroquinone is considered effective for improvement of periorbital skin hyperpigmentation, with a low incidence of postinflammatory hyperpigmentation.

Unassigned MURF1 of kinetoplastids codes for NADH dehydrogenase subunit 2

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Burger Gertraud

2008-10-01

Full Text Available Abstract Background In a previous study, we conducted a large-scale similarity-free function prediction of mitochondrion-encoded hypothetical proteins, by which the hypothetical gene murf1 (maxicircle unidentified reading frame 1 was assigned as nad2, encoding subunit 2 of NADH dehydrogenase (Complex I of the respiratory chain. This hypothetical gene occurs in the mitochondrial genome of kinetoplastids, a group of unicellular eukaryotes including the causative agents of African sleeping sickness and leishmaniasis. In the present study, we test this assignment by using bioinformatics methods that are highly sensitive in identifying remote homologs and confront the prediction with available biological knowledge. Results Comparison of MURF1 profile Hidden Markov Model (HMM against function-known profile HMMs in Pfam, Panther and TIGR shows that MURF1 is a Complex I protein, but without specifying the exact subunit. Therefore, we constructed profile HMMs for each individual subunit, using all available sequences clustered at various identity thresholds. HMM-HMM comparison of these individual NADH subunits against MURF1 clearly identifies this hypothetical protein as NAD2. Further, we collected the relevant experimental information about kinetoplastids, which provides additional evidence in support of this prediction. Conclusion Our in silico analyses provide convincing evidence for MURF1 being a highly divergent member of NAD2.

Case report: hydroquinone and/or glutaraldehyde induced acute myeloid leukaemia?

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Alexopoulos Evangelos C

2006-07-01

Full Text Available Abstract Background Exposures to high doses of irradiation, to chemotherapy, benzene, petroleum products, paints, embalming fluids, ethylene oxide, herbicides, pesticides, and smoking have been associated with an increased risk of acute myelogenous leukemia (AML. Although there in no epidemiological evidence of relation between X-ray developer, fixer and replenisher liquids and AML, these included glutaraldehyde which has weakly associated with lymphocytic leukemia in rats and hydroquinone has been increasingly implicated in producing leukemia, causing DNA and chromosomal damage, inhibits topo-isomerase II, alter hematopoiesis and inhibit apoptosis of neoplastic cells. Case presentation Two white females (A and B hired in 1985 as medical radiation technologists in a primary care center, in Greece. In July 2001, woman A, 38-years-old, was diagnosed as having acute monocytic leukaemia (FAB M5. The patient did not respond to therapy and died threeweeks later. In August 2001, woman B, 35-year-old, was diagnosed with acute promyelocytic leukaemia (FAB M3. Since discharge, she is in continuous complete remission. Both women were non smokers without any medical history. Shortly after these incidents official inspectors and experts inspected workplace, examined equipment, archives of repairs, notes, interviewed and monitored employees. They concluded that shielding was inadequate for balcony's door but personal monitoring did not show any exceeding of TLV of 20 mSv yearly and cytogenetics analysis did not reveal findings considered to be characteristics of ionizing exposure. Equipment for developing photos had a long list of repairs, mainly leakages of liquids and increases of temperature. On several occasions the floor has been flooded especially during 1987–1993 and 1997–2001. Inspection confirmed a complete lack of ventilation and many spoiled medical x-ray films. Employees reported that an "osmic" level was continuously evident and frequently

Stimulation of NADH-dependent microsomal DNA strand cleavage by rifamycin SV.

OpenAIRE

Kukiełka, E; Cederbaum, A I

1995-01-01

Rifamycin SV is an antibiotic anti-bacterial agent used in the treatment of tuberculosis. This drug can autoxidize, especially in the presence of metals, and generate reactive oxygen species. A previous study indicated that rifamycin SV can increase NADH-dependent microsomal production of reactive oxygen species. The current study evaluated the ability of rifamycin SV to interact with iron and increase microsomal production of hydroxyl radical, as detected by conversion of supercoiled plasmid...

Amperometric sensing of NADH and ethanol using a hybrid film electrode modified with electrochemically fabricated zirconia nanotubes and poly (acid fuchsin)

International Nuclear Information System (INIS)

Liu, X.; Li, B.; Zhan, G.; Liu, C.; Li, C.; Ma, M.

2012-01-01

We report on a glassy carbon electrode (GCE) modified with a film of chitosin containing acid fuchsin (AF) adsorbed onto zirconia nanotubes. The mixture was polymerized by cyclic voltammetric scannings in the potential range from - 0. 8 V to +1. 3 V in buffer solution to produce a hybrid film electrode (nano-ZrO 2 /PAF/GCE). The morphology of the hybrid film electrode surface was characterized by scanning electron microscopy. Its electrochemical properties were studied via electrochemical impedance spectroscopy. The electrochemical response of nicotinamide adenine dinucleotide (NADH) was investigated by differential pulse voltammetry and amperometry. The results indicated that the nano-ZrO 2 /PAF/GCE possesses well synergistic catalytic activity towards NADH. Compared to an unmodified GCE, the oxidation overpotential is negatively shifted by 224 mV, and the oxidation current is significantly increased. Under optimal conditions, the amperometric response is linearly proportional to the concentration of NADH in the 1. 0 - 100. 0 μM concentration range. Ethanol also can be determined by amperometry if alcohol dehydrogenase and NADH are added to the sample. Two linear relationships between current and alcohol concentration were obtained. They cover the range from 0. 03 to 1. 0 mM, and from 1. 0 to 12. 0 mM. (author)

Photochemical Properties and Reactivity of a Ru Compound Containing an NAD/NADH-Functionalized 1,10-Phenanthroline Ligand.

Science.gov (United States)

Kobayashi, Katsuaki; Ohtsu, Hideki; Nozaki, Koichi; Kitagawa, Susumu; Tanaka, Koji

2016-03-07

An NAD/NADH-functionalized ligand, benzo[b]pyrido[3,2-f][1,7]-phenanthroline (bpp), was newly synthesized. A Ru compound containing the bpp ligand, [Ru(bpp)(bpy)2](2+), underwent 2e(-) and 2H(+) reduction, generating the NADH form of the compound, [Ru(bppHH)(bpy)2](2+), in response to visible light irradiation in CH3CN/TEA/H2O (8/1/1). The UV-vis and fluorescent spectra of both [Ru(bpp)(bpy)2](2+) and [Ru(bppHH)(bpy)2](2+) resembled the spectra of [Ru(bpy)3](2+). Both complexes exhibited strong emission, with quantum yields of 0.086 and 0.031, respectively; values that are much higher than those obtained from the NAD/NADH-functionalized complexes [Ru(pbn)(bpy)2](2+) and [Ru(pbnHH)(bpy)2](2+) (pbn = (2-(2-pyridyl)benzo[b]-1.5-naphthyridine, pbnHH = hydrogenated form of pbn). The reduction potential of the bpp ligand in [Ru(bpp)(bpy)2](2+) (-1.28 V vs SCE) is much more negative than that of the pbn ligand in [Ru(pbn)(bpy)2](2+) (-0.74 V), although the oxidation potentials of bppHH and pbnHH are essentially equal (0.95 V). These results indicate that the electrochemical oxidation of the dihydropyridine moiety in the NADH-type ligand was independent of the π system, including the Ru polypyridyl framework. [Ru(bppHH)(bpy)2](2+) allowed the photoreduction of oxygen, generating H2O2 in 92% yield based on [Ru(bppHH)(bpy)2](2+). H2O2 production took place via singlet oxygen generated by the energy transfer from excited [Ru(bppHH)(bpy)2](2+) to triplet oxygen.

Effect of timing of joint application of hydroquinone and dicyandiamide on nitrous oxide emission from irrigated lowland rice paddy field.

Science.gov (United States)

Li, Xianglan; Zhang, Guangbin; Xu, Hua; Cai, Zucong; Yagi, Kazuyuki

2009-06-01

A field experiment was conducted to study the effect of timing of joint application of urease inhibitor hydroquinone (HQ) and nitrification inhibitor dicyandiamide (DCD) on N(2)O emission from irrigated lowland rice paddy field. Four treatments including Treatment CK (the control with urea alone), HQ/DCD-1 (application of HQ and DCD together with fertilizer before transplanting), HQ/DCD-2 (HQ and DCD with fertilizer at tillering stage) and HQ/DCD-3 (HQ and DCD with fertilizer at panicle initiation stage) were designed and implemented separately during rice growth period. Seasonal peaks of N(2)O flux occurred during midseason drainage and significant negative correlation between N(2)O flux and water layer depth was observed (r=-0.69 to -0.75, P<0.01). Mean N(2)O flux was the highest in the control with urea alone, while joint addition of HQ and DCD with urea lowered mean N(2)O flux considerably (P<0.05). Total N(2)O emission during rice growth season in Treatment CK, HQ/DCD-1, HQ/DCD-2 and HQ/DCD-3 was 3.90, 2.98, 1.73 and 3.23kgN(2)O-N ha(-1), respectively. Application of HQ and DCD together with basal fertilizer, tillering fertilizer and panicle initiation fertilizer decreased the total N(2)O emission by 24%, 56% and 17%, respectively, while increased grain yield by 10%, 18% and 6%, respectively. Effect of application of inhibitors on N(2)O emission during the continuous period from incorporation of HQ and DCD to rice harvest was also studied, where results indicating that the highest inhibiting efficiency of inhibitors on N(2)O emission was recorded when HQ and DCD applied with fertilizer at tillering stage.

Exogenous ochronosis after prolonged use of topical hydroquinone (2% in a 50-year-old Indian female

Directory of Open Access Journals (Sweden)

Vijay Gandhi

2012-01-01

Full Text Available Ochronosis is a rare disease characterized by speckled and diffuse pigmentation symmetrically over the face, neck, and photo-exposed areas. It is characterized histologically by banana-shaped ochre-colored deposits in the dermis. It can present in exogenous or endogenous form. We report a case of exogenous ochronosis in a 50-year-old Indian woman after prolonged use of topical hydroquinone which is a rare complication with a commonly used drug which is available over the counter.

Bioinspired Design of Alcohol Dehydrogenase@nano TiO2 Microreactors for Sustainable Cycling of NAD+/NADH Coenzyme

Directory of Open Access Journals (Sweden)

Sen Lin

2018-02-01

Full Text Available The bioinspired design and construction of enzyme@capsule microreactors with specific cell-like functionality has generated tremendous interest in recent years. Inspired by their fascinating complexity, scientists have endeavored to understand the essential aspects of a natural cell and create biomimicking microreactors so as to immobilize enzymes within the hierarchical structure of a microcapsule. In this study, simultaneous encapsulation of alcohol dehydrogenase (ADH was achieved during the preparation of microcapsules by the Pickering emulsion method using amphiphilic modified TiO2 nanoparticles (NPs as building blocks for assembling the photocatalytic microcapsule membrane. The ADH@TiO2 NP microreactors exhibited dual catalytic functions, i.e., spatially confined enzymatic catalysis and the membrane-associated photocatalytic oxidation under visible light. The sustainable cycling of nicotinamide adenine dinucleotide (NAD coenzyme between NADH and NAD+ was realized by enzymatic regeneration of NADH from NAD+ reduction, and was provided in a form that enabled further photocatalytic oxidation to NAD+ under visible light. This bioinspired ADH@TiO2 NP microreactor allowed the linking of a semiconductor mineral-based inorganic photosystem to enzymatic reactions. This is a first step toward the realization of sustainable biological cycling of NAD+/NADH coenzyme in synthetic functional microsystems operating under visible light irradiation.

Control of size and aspect ratio in hydroquinone-based synthesis of gold nanorods

Energy Technology Data Exchange (ETDEWEB)

Morasso, Carlo, E-mail: cmorasso@dongnocchi.it; Picciolini, Silvia; Schiumarini, Domitilla [Fondazione Don Carlo Gnocchi ONLUS, Laboratory of Nanomedicine and Clinical Biophotonics (LABION) (Italy); Mehn, Dora; Ojea-Jiménez, Isaac [European Commission Joint Research Centre, Institute for Health and Consumer Protection (IHCP) (Italy); Zanchetta, Giuliano [Universitá degli Studi di Milano, Dipartimento di Biotecnologie Mediche e Medicina Traslazionale (Italy); Vanna, Renzo; Bedoni, Marzia [Fondazione Don Carlo Gnocchi ONLUS, Laboratory of Nanomedicine and Clinical Biophotonics (LABION) (Italy); Prosperi, Davide [Università degli Studi di Milano Bicocca, NanoBioLab, Dipartimento di Biotecnologie e Bioscienze (Italy); Gramatica, Furio [Fondazione Don Carlo Gnocchi ONLUS, Laboratory of Nanomedicine and Clinical Biophotonics (LABION) (Italy)

2015-08-15

In this article, we describe how it is possible to tune the size and the aspect ratio of gold nanorods obtained using a highly efficient protocol based on the use of hydroquinone as a reducing agent by varying the amounts of CTAB and silver ions present in the “seed-growth” solution. Our approach not only allows us to prepare nanorods with a four times increased Au{sup 3+} reduction yield, when compared with the commonly used protocol based on ascorbic acid, but also allows a remarkable reduction of 50–60 % of the amount of CTAB needed. In fact, according to our findings, the concentration of CTAB present in the seed-growth solution do not linearly influence the final aspect ratio of the obtained nanorods, and an optimal concentration range between 30 and 50 mM has been identified as the one that is able to generate particles with more elongated shapes. On the optimized protocol, the effect of the concentration of Ag{sup +} ions in the seed-growth solution and the stability of the obtained particles has also been investigated.

Effect of different NADH oxidase levels on glucose metabolism by Lactococus lactis : kinetics of intracellular metabolite pools determined by in vivo nuclear magnetic resonance

NARCIS (Netherlands)

Neves, A.R.; Ramos, A.; Costa, H.; Swam, van I.I.; Hugenholtz, J.; Kleerebezem, M.; Vos, de W.M.; Santos, H.

2002-01-01

Three isogenic strains of Lactococcus lactis with different levels of H2O-forming NADH oxidase activity were used to study the effect of oxygen on glucose metabolism: the parent strain L. lactis MG1363, a NOX- strain harboring a deletion of the gene coding for H2O-forming NADH oxidase, and a NOX

Keeping disease at arm's length

DEFF Research Database (Denmark)

Lassen, Aske Juul

2015-01-01

active ageing change everyday life with chronic disease, and how do older people combine an active life with a range of chronic diseases? The participants in the study use activities to keep their diseases at arm’s length, and this distancing of disease at the same time enables them to engage in social...... and physical activities at the activity centre. In this way, keeping disease at arm’s length is analysed as an ambiguous health strategy. The article shows the importance of looking into how active ageing is practised, as active ageing seems to work well in the everyday life of the older people by not giving...... emphasis to disease. The article is based on ethnographic fieldwork and uses vignettes of four participants to show how they each keep diseases at arm’s length....

Purification and characterization of an H2O-forming NADH oxidase from Clostridium aminovalericum: existence of an oxygen-detoxifying enzyme in an obligate anaerobic bacteria.

Science.gov (United States)

Kawasaki, Shinji; Ishikura, Jun; Chiba, Daisuke; Nishino, Tomoko; Niimura, Youichi

2004-04-01

Clostridium aminovalericum, an obligate anaerobe, is unable to form colonies on PYD agar plates in the presence of 1% O(2). When grown anaerobically in PYD liquid medium, the strain can continue normal growth after the shift from anoxic (sparged with O(2)-free N(2) carrier-gas) to microoxic (sparged with 3% O(2)/97% N(2) mixed carrier-gas) growth conditions in the mid exponential phase (OD(660)=1.0). When the strain grew under 3% O(2)/97% N(2), the medium remains anoxic. Thirty minutes after beginning aeration with 3% O(2), the activity of NADH oxidase in cell-free extracts increased more than five-fold from the level before aeration. We purified NADH oxidase to determine the characteristics of this enzyme in an obligate anaerobe. The purified NADH oxidase dominated the NADH oxidase activity detected in cell-free extracts. The enzyme is a homotetramer composed of a subunit with a molecular mass of 45 kDa. The enzyme shows a spectrum typical of a flavoprotein, and flavin adenine dinucleotide (FAD) was identified as a cofactor. The final product of NADH oxidation was H(2)O, and the estimated K(m) for oxygen was 61.9 microM. These data demonstrate that an O(2)-response enzyme that is capable of detoxifying oxygen to water exists in C. aminovalericum.

Identification of a subunit of NADH-dehydrogenase as a p49/STRAP-binding protein

Directory of Open Access Journals (Sweden)

Zhong Ying

2008-01-01

Full Text Available Abstract Background The p49/STRAP (or SRFBP1 protein was recently identified in our laboratory as a cofactor of serum response factor that contributes to the regulation of SRF target genes in the heart. Results In the present study, we report that NDUFAB1, a nuclear encoded subunit of NADH dehydrogenase, represented the majority of the cDNA clones that interacted with p49/STRAP in multiple screenings using the yeast two-hybrid system. The p49/STRAP and NDUFAB1 proteins interacted and co-localized with each other in the cell. The p49/STRAP protein contains four classic nuclear localization sequence motifs, and it was observed to be present predominantly in the nucleus. Overexpression of p49/STRAP altered the intracellular level of NAD, and reduced the NAD/NADH ratio. Overexpression of p49/STRAP also induced the deacetylation of serum response factor. Conclusion These data suggest that p49/STRAP plays a role in the regulation of intracellular processes such as cardiac cellular metabolism, gene expression, and possibly aging.

Development of an Electrochemical Sensor for NADH Determination Based on a Caffeic Acid Redox Mediator Supported on Carbon Black

Directory of Open Access Journals (Sweden)

Chiara Zanardi

2015-04-01

Full Text Available Screen-printed electrode (SPE modified with carbon black nanoparticles (CB has been tested as a new platform for the stable deposition of caffeic acid (CFA on the electrode surface. The electrochemical performance from varying the amount of CFA/CB composite has been tested with respect to NADH determination. The electrocatalytic activity of CFA/CB has also been compared with that of SPEs modified by a single component of the coating, i.e., either CFA or CB. Finally, glycerol dehydrogenase, a typical NADH-dependent enzyme, was deposited on the CFA/CB coating in order to test the applicability of the sensor in glycerol determination.

NADH-fluorescence scattering correction for absolute concentration determination in a liquid tissue phantom using a novel multispectral magnetic-resonance-imaging-compatible needle probe

Science.gov (United States)

Braun, Frank; Schalk, Robert; Heintz, Annabell; Feike, Patrick; Firmowski, Sebastian; Beuermann, Thomas; Methner, Frank-Jürgen; Kränzlin, Bettina; Gretz, Norbert; Rädle, Matthias

2017-07-01

In this report, a quantitative nicotinamide adenine dinucleotide hydrate (NADH) fluorescence measurement algorithm in a liquid tissue phantom using a fiber-optic needle probe is presented. To determine the absolute concentrations of NADH in this phantom, the fluorescence emission spectra at 465 nm were corrected using diffuse reflectance spectroscopy between 600 nm and 940 nm. The patented autoclavable Nitinol needle probe enables the acquisition of multispectral backscattering measurements of ultraviolet, visible, near-infrared and fluorescence spectra. As a phantom, a suspension of calcium carbonate (Calcilit) and water with physiological NADH concentrations between 0 mmol l-1 and 2.0 mmol l-1 were used to mimic human tissue. The light scattering characteristics were adjusted to match the backscattering attributes of human skin by modifying the concentration of Calcilit. To correct the scattering effects caused by the matrices of the samples, an algorithm based on the backscattered remission spectrum was employed to compensate the influence of multiscattering on the optical pathway through the dispersed phase. The monitored backscattered visible light was used to correct the fluorescence spectra and thereby to determine the true NADH concentrations at unknown Calcilit concentrations. Despite the simplicity of the presented algorithm, the root-mean-square error of prediction (RMSEP) was 0.093 mmol l-1.

Silver nanoparticles embedded in amine-functionalized silicate sol–gel network assembly for sensing cysteine, adenosine and NADH

International Nuclear Information System (INIS)

Maduraiveeran, Govindhan; Ramaraj, Ramasamy

2011-01-01

Silver nanoparticles embedded in amine-functionalized silicate sol–gel network were synthesized and used for sensing biomolecules such as cysteine, adenosine, and β-nicotinamide adenine dinucleotide (NADH). The sensing of these biomolecules by the assembly of silver nanoparticles was triggered by the optical response of the surface plasmon resonance (SPR) of the silver nanoparticles. The optical sensor exhibited the lowest detection limit (LOD) of 5, 20, and 5 μM for cysteine, adenosine, and NADH, respectively. The sensing of biomolecules in the micromolar range by using the amine-functionalized silicate sol–gel embedded silver nanoparticles was studied in the presence of interference molecules like uridine, glycine, guanine, and guanosine. Thus, the present approach might open up a new avenue for the development of silver nanoparticles-based optical sensor devices for biomolecules.

A glassy carbon electrode modified with cerium phosphate nanotubes for the simultaneous determination of hydroquinone, catechol and resorcinol.

Science.gov (United States)

Li, Zhen; Yue, Yuhua; Hao, Yanjun; Feng, Shun; Zhou, Xianli

2018-03-12

A nafion film containing cerium phosphate nanotubes was pasted onto a glassy carbon electrode (GCE) to obtain a sensor for hydroquinone (HQ). The morphologies and components of the coating were characterized by transmission electron microscopy, scanning electron microscopy and energy-dispersive spectroscopy. Cyclic voltammetry and differential pulse voltammetry (DPV) showed the specific surface of the electrode to be significantly increased and the electron transfer rate to be accelerated. The modified GCE was applied to the determination of hydroquinone (HQ) via DPV. The oxidation current increases linearly in the 0.23 μM to 16 mM HQ concentration range which is as wide as five orders of magnitude. The limit of detection is 0.12 μM (based on a signal-to-noise ratio of 3), and the sensitivity is 1.41 μA·μM -1  cm -2 . The method was further applied to the simultaneous determination of HQ, catechol and resorcinol. The potentials for the three species are well separated (20, 134, and 572 mV vs SCE). Average recoveries from (spiked) real water samples are between 95.2 and 107.0%, with relative standard deviations of 0.9~2.7% (for n = 3) at three spiking levels. The method was validated by independent assays using HPLC. Graphical abstract ᅟ.

Increased availability of NADH in metabolically engineered baker's yeast improves transaminase-oxidoreductase coupled asymmetric whole-cell bioconversion

DEFF Research Database (Denmark)

Knudsen, Jenny Dahl; Hägglöf, Cecilia; Weber, Nora

2016-01-01

yeast for transamination-reduction coupled asymmetric one-pot conversion was investigated. RESULTS: A series of active whole-cell biocatalysts were constructed by over-expressing the (S)-selective ω-transaminase (VAMT) from Capsicum chinense together with the NADH-dependent (S)-selective alcohol...

Detection of NADH via electrocatalytic oxidation at single-walled carbon nanotubes modified with Variamine blue

International Nuclear Information System (INIS)

Radoi, A.; Compagnone, D.; Valcarcel, M.A.; Placidi, P.; Materazzi, S.; Moscone, D.; Palleschi, G.

2008-01-01

Screen-printed electrodes (SPEs) modified with Variamine blue (VB), covalently attached to the oxidized single-walled carbon nanotubes (SWCNTs-COOH), were developed and used as chemical sensors for the detection of the reduced nicotinamide adenine dinucleotide (NADH). The Variamine blue redox mediator was covalently linked to the SWCNTs-COOH by the N,N'-dicyclohexylcarbodiimide (DCC) and N-hydroxysuccinimide (NHS) chemistry. Infrared Fourier transform (FT-IR) spectroscopy revealed the presence of the amide bands situated at 1623 cm -1 (I band), 1577 cm -1 (II band) and 1437 cm -1 (III band) demonstrating the covalent linkage of Variamine blue to SWCNTs-COOH. The heterogeneous electron transfer rate, k obs. , was 13,850 M -1 s -1 , and the k s and α were 0.8 s -1 and 0.56, respectively. The pH dependence was also investigated. SPEs modified with Variamine blue by using the DCC/NHS conjugation method, showed a variation of -36 mV per pH unit. A successful application was the development of a lactate biosensor obtained by the immobilization of the L-lactate dehydrogenase on the NADH sensor

Inhibitors of type II NADH:menaquinone oxidoreductase represent a class of antitubercular drugs

OpenAIRE

Weinstein, Edward A.; Yano, Takahiro; Li, Lin-Sheng; Avarbock, David; Avarbock, Andrew; Helm, Douglas; McColm, Andrew A.; Duncan, Ken; Lonsdale, John T.; Rubin, Harvey

2005-01-01

Mycobacterium tuberculosis (Mtb) is an obligate aerobe that is capable of long-term persistence under conditions of low oxygen tension. Analysis of the Mtb genome predicts the existence of a branched aerobic respiratory chain terminating in a cytochrome bd system and a cytochrome aa3 system. Both chains can be initiated with type II NADH:menaquinone oxidoreductase. We present a detailed biochemical characterization of the aerobic respiratory chains from Mtb and show that phenothiazine analogs...

Enhancement of radiation effect using beta-lapachone and underlying mechanism

International Nuclear Information System (INIS)

Ahn, Ki Jung; Lee, Hyung Sik; Bai, Se Kyung; Song, Chang Won

2013-01-01

Beta-lapachone (β-Lap; 3,4-dihydro-2, 2-dimethyl-2H-naphthol[1, 2-b]pyran-5,6-dione) is a novel anti-cancer drug under phase I/II clinical trials. (β-Lap has been demonstrated to cause apoptotic and necrotic death in a variety of human cancer cells in vitro and in vivo. The mechanisms underlying the (β-Lap toxicity against cancer cells has been controversial. The most recent view is that (β-Lap, which is a quinone compound, undergoes two-electron reduction to hydroquinone form utilizing NAD(P)H or NADH as electron source. This two-electron reduction of (β-Lap is mediated by NAD(P)H:quinone oxidoreductase (NQO1), which is known to mediate the reduction of many quinone compounds. The hydroquinone forms of (β-Lap then spontaneously oxidizes back to the original oxidized (β-Lap, creating futile cycling between the oxidized and reduced forms of (β-Lap. It is proposed that the futile recycling between oxidized and reduced forms of (β-Lap leads to two distinct cell death pathways. First one is that the two-electron reduced (β-Lap is converted first to one-electron reduced (β-Lap, i.e., semiquinone (β-Lap (SQ)- causing production of reactive oxygen species (ROS), which then causes apoptotic cell death. The second mechanism is that severe depletion of NAD(P)H and NADH as a result of futile cycling between the quinone and hydroquinone forms of β- p causes severe disturbance in cellular metabolism leading to apoptosis and necrosis. The relative importance of the aforementioned two mechanisms, i.e., generation of ROS or depletion of NAD(P)H/NADH, may vary depending on cell type and environment. Importantly, the NQO1 level in cancer cells has been found to be higher than that in normal cells indicating that β-Lap may be preferentially toxic to cancer cells relative to non-cancer cells. The cellular level of NQO1 has been found to be significantly increased by divergent physical and chemical stresses including ionizing radiation. Recent reports clearly demonstrated

Increasing NADH oxidation reduces overflow metabolism in Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Vemuri, Goutham; Eiteman, M.A; McEwen, J.E

2007-01-01

effect is due to limited respiratory capacity or is caused by glucose-mediated repression of respiration. When respiration in S. cerevisiae was increased by introducing a heterologous alternative oxidase, we observed reduced aerobic ethanol formation. In contrast, increasing nonrespiratory NADH oxidation...... Crabtree effect.’’ The yeast Saccharomyces cerevisiae has served as an important model organism for studying the Crabtree effect. When subjected to increasing glycolytic fluxes under aerobic conditions, there is a threshold value of the glucose uptake rate at which the metabolism shifts from purely...... respiratory to mixed respiratory and fermentative. It is well known that glucose repression of respiratory pathways occurs at high glycolytic fluxes, resulting in a decrease in respiratory capacity. Despite many years of detailed studies on this subject, it is not known whether the onset of the Crabtree...

Engineering a synthetic anaerobic respiration for reduction of xylose to xylitol using NADH output of glucose catabolism by Escherichia coli AI21.

Science.gov (United States)

Iverson, Andrew; Garza, Erin; Manow, Ryan; Wang, Jinhua; Gao, Yuanyuan; Grayburn, Scott; Zhou, Shengde

2016-04-16

Anaerobic rather than aerobic fermentation is preferred for conversion of biomass derived sugars to high value redox-neutral and reduced commodities. This will likely result in a higher yield of substrate to product conversion and decrease production cost since substrate often accounts for a significant portion of the overall cost. To this goal, metabolic pathway engineering has been used to optimize substrate carbon flow to target products. This approach works well for the production of redox neutral products such as lactic acid from redox neutral sugars using the reducing power NADH (nicotinamide adenine dinucleotide, reduced) generated from glycolysis (2 NADH per glucose equivalent). Nevertheless, greater than two NADH per glucose catabolized is needed for the production of reduced products (such as xylitol) from redox neutral sugars by anaerobic fermentation. The Escherichia coli strain AI05 (ΔfrdBC ΔldhA ΔackA Δ(focA-pflB) ΔadhE ΔptsG ΔpdhR::pflBp 6-(aceEF-lpd)), previously engineered for reduction of xylose to xylitol using reducing power (NADH equivalent) of glucose catabolism, was further engineered by 1) deleting xylAB operon (encoding for xylose isomerase and xylulokinase) to prevent xylose from entering the pentose phosphate pathway; 2) anaerobically expressing the sdhCDAB-sucABCD operon (encoding for succinate dehydrogenase, α-ketoglutarate dehydrogenase and succinyl-CoA synthetase) to enable an anaerobically functional tricarboxcylic acid cycle with a theoretical 10 NAD(P)H equivalent per glucose catabolized. These reducing equivalents can be oxidized by synthetic respiration via xylose reduction, producing xylitol. The resulting strain, AI21 (pAI02), achieved a 96 % xylose to xylitol conversion, with a yield of 6 xylitol per glucose catabolized (molar yield of xylitol per glucose consumed (YRPG) = 6). This represents a 33 % improvement in xylose to xylitol conversion, and a 63 % increase in xylitol yield per glucose catabolized over

40 CFR 1068.455 - What records must I keep?

Science.gov (United States)

2010-07-01

... CONTROLS GENERAL COMPLIANCE PROVISIONS FOR ENGINE PROGRAMS Selective Enforcement Auditing § 1068.455 What records must I keep? (a) We may review your records at any time so it is important to keep required...) If you shipped the engine/equipment for testing, the date you shipped it, the associated storage or...

Selection of reference genes for expression analysis using quantitative real-time PCR in the pea aphid, Acyrthosiphon pisum (Harris (Hemiptera, Aphidiae.

Directory of Open Access Journals (Sweden)

Chunxiao Yang

Full Text Available To facilitate gene expression study and obtain accurate qRT-PCR analysis, normalization relative to stable expressed housekeeping genes is required. In this study, expression profiles of 11 candidate reference genes, including actin (Actin, elongation factor 1 α (EF1A, TATA-box-binding protein (TATA, ribosomal protein L12 (RPL12, β-tubulin (Tubulin, NADH dehydrogenase (NADH, vacuolar-type H+-ATPase (v-ATPase, succinate dehydrogenase B (SDHB, 28S ribosomal RNA (28S, 16S ribosomal RNA (16S, and 18S ribosomal RNA (18S from the pea aphid Acyrthosiphon pisum, under different developmental stages and temperature conditions, were investigated. A total of four analytical tools, geNorm, Normfinder, BestKeeper, and the ΔCt method, were used to evaluate the suitability of these genes as endogenous controls. According to RefFinder, a web-based software tool which integrates all four above-mentioned algorithms to compare and rank the reference genes, SDHB, 16S, and NADH were the three most stable house-keeping genes under different developmental stages and temperatures. This work is intended to establish a standardized qRT-PCR protocol in pea aphid and serves as a starting point for the genomics and functional genomics research in this emerging insect model.

Mediated oxidation of hydroquinone on poly(N-ethylcarbazole): Analysis of transport and kinetic phenomena by impedance techniques

Energy Technology Data Exchange (ETDEWEB)

Deslouis, C.; Tribollet, B. (Physique des Liquides et Electrochimie Lab., Univ. Pierre et Marie Curie, 75 - Paris (France)); Musiani, M.M. (Ist. di Polarografia ed Elettrochimica Preparativa del CNR, Padua (Italy))

1990-09-01

The oxidation of hydroquinone on Pt electrodes modified by electrosynthesized p-ethylcarbazole is studied in 5 M HClO{sub 4}. Electrohydrodynamical and a.c. impedance measurements yield the redox capacitance of the film and electron diffusivity D{sub E} with reasonable dependence on the thickness. D{sub E} values near to 10{sup -7} cm{sup 2} s{sup -1} confirm the average conductivity of this polymer. Change-transfer resistances in agreement with {alpha}=0.5 are measured. These results {alpha} posteriori justify the hypotheses put forward when developing the theoretical impedance model used for the analysis of the data. (orig.).

Biology, Culture, and the Origins of Pet-Keeping

Directory of Open Access Journals (Sweden)

Harold A. Herzog

2014-08-01

Full Text Available Attachments between non-human animals of different species are surprisingly common in situations involving human agency (e.g., homes, zoos, and wildlife parks. However, cross-species animal friendships analogous to pet-keeping by humans are at least rare and possibly non-existent in nature. Why has pet-keeping evolved only in Homo sapiens? I review theories that explain pet-keeping either as an adaptation or an evolutionary by-product. I suggest that these explanations cannot account for the wide variation in the distribution and forms of pet-keeping across human societies and over historical time. Using fluctuations in the popularity of dog breeds in the United States, I show how shifts in choices of pets follow the rapid changes in preferences that characterize fashion cycles. I argue that while humans possess some innate traits that facilitate attachment to members of other species (e.g., parental urges, attraction to creatures with infantile features, pet-keeping is largely a product of social learning and imitation-based cultural evolution.

Catalytic properties of nickel ferrites for oxidation of glucose, β-nicotiamide adenine dinucleotide (NADH) and methanol

Energy Technology Data Exchange (ETDEWEB)

Galindo, R. [Departamento de Química, Universidad de Guanajuato, Cerro de la Venada s/n, Pueblito de Rocha, C.P. 36040 Guanajuato, Gto (Mexico); Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, Cantoblanco s/n, C.P. 28049 Madrid (Spain); Gutiérrez, S. [Departamento de Química, Universidad de Guanajuato, Cerro de la Venada s/n, Pueblito de Rocha, C.P. 36040 Guanajuato, Gto (Mexico); Menéndez, N. [Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, Cantoblanco s/n, C.P. 28049 Madrid (Spain); Herrasti, P., E-mail: pilar.herrasti@uam.es [Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, Cantoblanco s/n, C.P. 28049 Madrid (Spain)

2014-02-15

Highlights: ► NiFe{sub 2}O{sub 4} nanoparticles obtained by electrochemical method are effective catalyst. ► A partially inverse spinel was obtained with 57% Fe{sup 3+} in tetrahedral position. ► A non-enzymatic electrode using NiFe{sub 2}O{sub 4} nanoparticles has been manufactured. -- Abstract: Nickel ferrite nanoparticles (NiFe{sub 2}O{sub 4}) were synthesized by electrochemical method and used as catalyst for direct oxidation of glucose, NADH and methanol. Characterization of these nanoparticles was carried out by X-ray diffraction, Mössbauer spectroscopy, and colloidal properties such as hydrodynamic radius and Zeta potential. To evaluate the catalytic properties of these nanoparticles against the oxidation process, paste graphite electrodes mixing nickel ferrites and different conductive materials (graphite, carbon nanotubes) and binders agents (mineral oil, 1-octylpyridinium hexafluorophosphate (nOPPF6)) were used. The results prove good catalytic properties of these materials, with an oxidation potential around 0.75, 0.5 and 0.8 V for glucose, NADH, and methanol, respectively.

Molecular cloning of cDNAs of human liver and placenta NADH-cytochrome b5 reductase

International Nuclear Information System (INIS)

Yubisui, T.; Naitoh, Y.; Zenno, S.; Tamura, M.; Takeshita, M.; Sakaki, Y.

1987-01-01

A cDNA coding for human liver NADH-cytochrome b 5 reductase was cloned from a human liver cDNA library constructed in phage λgt11. The library was screened by using an affinity-purified rabbit antibody against NADH-cytochrome b 5 reductase of human erythrocytes. A cDNA about 1.3 kilobase pairs long was isolated. By using the cDNA as a probe, another cDNA (pb 5 R141) of 1817 base pairs was isolated that hybridized with a synthetic oligonucleotide encoding Pro-Asp-Ile-Lys-Tyr-Pro, derived from the amino acid sequence at the amino-terminal region of the enzyme from human erythrocytes. Furthermore, by using the pb 5 R141 as a probe, cDNA clones having more 5' sequence were isolated from a human placenta cDNA library. The amino acid sequences deduced from the nucleotide sequences of these cDNA clones overlapped each other and consisted of a sequence that completely coincides with that of human erythrocytes and a sequence of 19 amino acid residues extended at the amino-terminal side. The latter sequence closely resembles that of the membrane-binding domain of steer liver microsomal enzyme

Keeping the security and the relief in the environment where radioactive materials exist all the times

International Nuclear Information System (INIS)

Murata, Takashi

2014-01-01

Three-Eleven was a turning point after which we have recognized that are surrounded by the radioactive materials all the times. On the other hand, “getting a claim to edit by any individual” became possible owing to the spread of advanced ICT equipment, and now he can get necessary information for him to decide and act as he want. It is important for keeping security and rejecting anxiety against radiation to record and evaluate personal irradiation information utilizing the results of ICT. The results should be timely returned to the concerned person. At the same time, it necessary to establish the system by which the data are compiled as a big data and are opened for public use. For establishing such system, the promotion of interdisciplinary collaboration is expected. (J.P.N.)

Hydroquinone and Quinone-Grafted Porous Carbons for Highly Selective CO2 Capture from Flue Gases and Natural Gas Upgrading.

Science.gov (United States)

Wang, Jun; Krishna, Rajamani; Yang, Jiangfeng; Deng, Shuguang

2015-08-04

Hydroquinone and quinone functional groups were grafted onto a hierarchical porous carbon framework via the Friedel-Crafts reaction to develop more efficient adsorbents for the selective capture and removal of carbon dioxide from flue gases and natural gas. The oxygen-doped porous carbons were characterized with scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. CO2, CH4, and N2 adsorption isotherms were measured and correlated with the Langmuir model. An ideal adsorbed solution theory (IAST) selectivity for the CO2/N2 separation of 26.5 (298 K, 1 atm) was obtained on the hydroquinone-grafted carbon, which is 58.7% higher than that of the pristine porous carbon, and a CO2/CH4 selectivity value of 4.6 (298 K, 1 atm) was obtained on the quinone-grafted carbon (OAC-2), which represents a 28.4% improvement over the pristine porous carbon. The highest CO2 adsorption capacity on the oxygen-doped carbon adsorbents is 3.46 mmol g(-1) at 298 K and 1 atm. In addition, transient breakthrough simulations for CO2/CH4/N2 mixture separation were conducted to demonstrate the good separation performance of the oxygen-doped carbons in fixed bed adsorbers. Combining excellent adsorption separation properties and low heats of adsorption, the oxygen-doped carbons developed in this work appear to be very promising for flue gas treatment and natural gas upgrading.

Strategies To Keep Secret Through Sophie Kinsella’s Novel “Can You Keep A Secret”

OpenAIRE

Sihombing, Mariaty A.

2015-01-01

The paper entitled “Strategies to Keep Secret Through Sophie Kinsella’a novel : Can You Keep a Secret is about Emma Corrigan who like every girl in the world. She has a few little secrets. Can You Keep a Secret is the fifth novel that written by Sophie Kinsella and get best seller. The writer discusses about the strategies to keep secret. The strategies are Trust, Silence, and Cooperation. The writer interested in analyzing this novel, because it’s contain some informantions about keeping a s...

Direct Electrodeposition of Gold Nanoparticles on Glassy Carbon Electrode for Selective Determination Catechol in the Presence of Hydroquinone.

Science.gov (United States)

Jayakumar, C; Magdalane, C Maria; Kaviyarasu, K; Kulandainathan, M Anbu; Jeyaraj, Boniface; Maaza, M

2018-07-01

A simple and reliable voltammetric sensor for simultaneous determination of Catechol (CT) and Hydroquinone (HQ) was developed by electrodepositing the gold nanoparticles on the surface of the Glassy Carbon Electrode (GCE). The cyclic voltammograms in a mixed solution of CT and HQ have shown that the oxidation peaks become well resolved and were separated by 110 mV, although the bare GCE gave a single broad oxidation peak. Moreover, the oxidation peak currents of both CT and HQ were remarkably increased three times in comparison with the bare GCE. This makes gold nanoparticles deposited GCE a suitable candidate for the determination of these isomers. In the presence of 1 mM HQ isomer, the oxidation peak currents of differential pulse voltammograms are proportional to the concentration of CT in the range of 21 μM to 323 μM with limit of detection 3.0 μM (S/N = 3). The proposed sensor has some important advantages such as low cost, ease of preparation, good stability and high reproducibility.

Hydroquinone PBPK model refinement and application to dermal exposure.

Science.gov (United States)

Poet, Torka S; Carlton, Betsy D; Deyo, James A; Hinderliter, Paul M

2010-11-01

A physiologically based pharmacokinetic (PBPK) model for hydroquinone (HQ) was refined to include an expanded description of HQ-glucuronide metabolites and a description of dermal exposures to support route-to-route and cross-species extrapolation. Total urinary excretion of metabolites from in vivo rat dermal exposures was used to estimate a percutaneous permeability coefficient (K(p); 3.6×10(-5) cm/h). The human in vivo K(p) was estimated to be 1.62×10(-4) cm/h, based on in vitro skin permeability data in rats and humans and rat in vivo values. The projected total multi-substituted glutathione (which was used as an internal dose surrogate for the toxic glutathione metabolites) was modeled following an exposure scenario based on submersion of both hands in a 5% aqueous solution of HQ (similar to black and white photographic developing solution) for 2 h, a worst-case exposure scenario. Total multi-substituted glutathione following this human dermal exposure scenario was several orders of magnitude lower than the internal total glutathione conjugates in rats following an oral exposure to the rat NOEL of 20 mg/kg. Thus, under more realistic human dermal exposure conditions, it is unlikely that toxic glutathione conjugates (primarily the di- and, to a lesser degree, the tri-glutathione conjugate) will reach significant levels in target tissues. Copyright © 2010. Published by Elsevier Ltd.

[How can I keep up with my literature?].

Science.gov (United States)

Vandenbroucke, J P

1998-03-28

To keep up with the literature, the author and his wife have personal home subscriptions to the 'big five' general medical journals, two top general science journals, and close to a dozen specialist journals. Two of the general medical journals are regularly read in more depth. Since computerized search systems permit almost immediate retrieval on whatever subject at whatever work location, the author keeps no filing system of the items of interest. For three (slowly growing) subjects that transgress the boundaries of the usual keywords of search systems, copies of papers are collected in piles: (a) important methodological papers (which may have been published anywhere, on any subject), (b) papers about concepts of the origin and evolution of diseases, and (c) papers of strong general interest. The disadvantage of not keeping track of the literature by a personal filing system is that the author regularly forgets about papers and books he already has; the advantage is that no time is spent keeping a personal filing system.

Over-expression of NADH-dependent oxidoreductase (fucO) for increasing furfural or 5-hydroxymethylfurfural tolerance

Science.gov (United States)

Miller, Elliot N.; Zhang, Xueli; Yomano, Lorraine P.; Wang, Xuan; Shanmugam, Keelnatham T.; Ingram, Lonnie O'Neal

2015-10-13

The subject invention pertains to the discovery that the NADH-dependent propanediol oxidoreductase (FucO) can reduce furfural. This allows for a new approach to improve furfural tolerance in bacterial and/or yeast cells used to produce desired products. Thus, novel biocatalysts (bacterial, fungal or yeast cells) exhibiting increased tolerance to furfural and 5-hydroxymethylfurfural (5-HMF) are provided as are methods of making and using such biocatalysts for the production of a desired product.

Contribution of the NADH-oxidase (Nox) to the aerobic life of Lactobacillus sanfranciscensis DSM20451T.

Science.gov (United States)

Jänsch, André; Freiding, Simone; Behr, Jürgen; Vogel, Rudi F

2011-02-01

Lactobacillus sanfranciscensis is the key bacterium in traditional sourdough fermentation. The molecular background of its oxygen tolerance was investigated by comparison of wild type and NADH-oxidase (Nox) knock out mutants. The nox gene of L. sanfranciscensis DSM20451(T) coding for a NADH-oxidase (Nox) was inactivated by single crossover integration to yield strain L. sanfranciscensis DSM20451Δnox. By inactivation of the native NADH-oxidase gene, it was ensured that besides fructose, O(2) can react as an electron acceptor. In aerated cultures the mutant strain was only able to grow in MRS media supplemented with fructose as electron acceptor, whereas the wild type strain showed a fructose independent growth response. The use of oxygen as an external electron acceptor enables L. sanfranciscensis to shift from acetyl-phosphate into the acetate branch and gain an additionally ATP, while the reduced cofactors were regenerated by Nox-activity. In aerated cultures the wild type strain formed a fermentation ratio of lactate to acetate of 1.09 in MRS supplemented with fructose after 24 h of fermentation, while the mutant strain formed a fermentation ratio of 3.05. Additionally, L. sanfranciscensis showed manganese-dependent growth response in aerated cultures, the final OD and growth velocity was increased in media supplemented with manganese. The expression of two predicted Mn(2+)/Fe(2+) transporters MntH1 and MntH2 in L. sanfranciscensis DSM20451(T) was verified by amplification of a 318 bp fragment of MntH1 and a 239 bp fragment of MntH2 from cDNA library obtained from aerobically, exponentially growing cells of L. sanfranciscensis DSM20451(T) in MRS. Moreover, the mutant strain DSM20451Δnox was more sensitive to the superoxide generating agent paraquat and showed inhibition of growth on diamide-treated MRS-plates without fructose supplementation. Copyright © 2010 Elsevier Ltd. All rights reserved.

Screening for occupational vitiligo in workers exposed to hydroquinone monomethyl ether and to paratertiary-amyl-phenol

Energy Technology Data Exchange (ETDEWEB)

O' Sullivan, J.J.; Stevenson, C.J.

1981-11-01

Two men reported previously with vitiligo after occupational exposure to hydroquinone monomethyl ether (HMME) have been reviewed after eight years. Repigmentation of significant degree was found in one man and of limited degree in the other. One hundred and sixty-nine men in the same works have been screened with Wood's light for evidence of vitiligo. No cases were found in the 148 men exposed to HMME (colleagues who screened 100 men exposed to HMME in two other factories also found no case) or in the 129 who had been exposed to paratertiary-amyl-phenol. Loss of light reflection on Wood's light examination was observed in 13 men due to scars or to other skin disorders.

Hairpin stabilized fluorescent silver nanoclusters for quantitative detection of NAD+ and monitoring NAD+/NADH based enzymatic reactions.

Science.gov (United States)

Jain, Priyamvada; Chakma, Babina; Patra, Sanjukta; Goswami, Pranab

2017-03-01

A set of 90 mer long ssDNA candidates, with different degrees of cytosine (C-levels) (% and clusters) was analyzed for their function as suitable Ag-nanocluster (AgNC) nucleation scaffolds. The sequence (P4) with highest C-level (42.2%) emerged as the only candidate supporting the nucleation process as evident from its intense fluorescence peak at λ 660 nm . Shorter DNA subsets derived from P4 with only stable hairpin structures could support the AgNC formation. The secondary hairpin structures were confirmed by PAGE, and CD studies. The number of base pairs in the stem region also contributes to the stability of the hairpins. A shorter 29 mer sequence (Sub 3) (ΔG = -1.3 kcal/mol) with 3-bp in the stem of a 7-mer loop conferred highly stable AgNC. NAD + strongly quenched the fluorescence of Sub 3-AgNC in a concentration dependent manner. Time resolved photoluminescence studies revealed the quenching involves a combined static and dynamic interaction where the binding constant and number of binding sites for NAD + were 0.201 L mol -1 and 3.6, respectively. A dynamic NAD + detection range of 50-500 μM with a limit of detection of 22.3 μM was discerned. The NAD + mediated quenching of AgNC was not interfered by NADH, NADP + , monovalent and divalent ions, or serum samples. The method was also used to follow alcohol dehydrogenase and lactate dehydrogenase catalyzed physiological reactions in a turn-on and turn-off assay, respectively. The proposed method with ssDNA-AgNC could therefore be extended to monitor other NAD + /NADH based enzyme catalyzed reactions in a turn-on/turn-off approach. Copyright © 2016 Elsevier B.V. All rights reserved.

30 CFR 250.401 - What must I do to keep wells under control?

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false What must I do to keep wells under control? 250... General Requirements § 250.401 What must I do to keep wells under control? You must take necessary precautions to keep wells under control at all times. You must: (a) Use the best available and safest drilling...

The plasma membrane-associated NADH oxidase of spinach leaves responds to blue light

Science.gov (United States)

Morre, D. James; Penel, Claude; Greppin, Hubert; Morre, Dorothy M.

2002-01-01

The plasma membrane-associated NADH oxidase (NOX) of spinach leaf disks is characterized by oscillations in activity with a regular period length of ca. 24 min. Within a single population of plants exposed to light at the same time, NOX activities of all plants function synchronously. Exposure of plants transferred from darkness to blue light (495 nm, 2 min, 50 micromoles m-2 s-1) resulted in a complex response pattern but with a new maximum in the rate of NOX activity 36 (24+12) min after illumination and then with maxima in the rate of NOX activity every 24 min thereafter. Transient maxima in NOX activity were observed as well after 9.3 + /- 1.4 and 20.7 +/- 2.1 min. The blue light response differed from the response to red (650 nm, 10 min, 50 micromoles m-2 s-1) or white light where activity maxima were initiated 12 min after the light exposure followed by maxima every 24 min thereafter. Green or yellow light was ineffective. The light response was independent of the time in the 24-min NOX cycle when the light was given. The net effects of blue and red light were ultimately the same with a new maximum in the rate of NOX activity at 12+24=36 min (and every 24 min thereafter), but the mechanisms appear to be distinct.

Keeping time - Performing Place

DEFF Research Database (Denmark)

Dvinge, Anne Christine

2012-01-01

Candace Allen’s novel Valaida (2004) illustrates the migratory patterns of early 20th century jazz music and musicians, positing the art form and its performers as “heterotopians”; simultaneously in and outside of the power relations of hegemonic time-space compression, travelling in an alternate...

Keeping Noise Down on the Farm

Science.gov (United States)

... Do > Keeping Noise Down on the Farm Keeping Noise Down on the Farm SHARE Some people may ... risks permanent hearing damage. Take steps to reduce noise from machinery. Keep machinery running smoothly by replacing ...

Keeping a Journal: A Path to Uncovering Identity (and Keeping Your Sanity)

Science.gov (United States)

Cooper, Joanne E.

2013-01-01

A journal can help keep a person more organized, clarify their identity, and help them grapple with them own sense of belonging in the often bewildering world of academe. In this article, the author discusses: (1) the benefits and uses of keeping a journal; (2) Techniques for writing in a journal; and (3) Drawbacks of journal writing.

JST Thesaurus Headwords and Synonyms: NADH,NADPHオキシドレダクターゼ [MeCab user dictionary for science technology term[Archive

Lifescience Database Archive (English)

Full Text Available MeCab user dictionary for science technology term NADH,NADPHオキシドレダクターゼ 名詞 一般 * * * ...* ＮＡＤ（Ｐ）Ｈオキシドレダクターゼ ＮＡＤ（Ｐ）Ｈオキシドレダクターゼ エヌエイディー（ピー）エイチオキシドレダクターゼ Thesaurus2015 200906027745899279 C LS38 UNKNOWN_2 NADH , NADPH オキシドレダクターゼ

One-step construction of an electrode modified with electrodeposited Au/SiO2 nanoparticles, and its application to the determination of NADH and ethanol

International Nuclear Information System (INIS)

Liu, X.; Li, B.; Wang, X.; Li, C.

2010-01-01

A new electrode was developed by one-step potentiostatic electrodeposition (at -2. 0 V for 20 s) of Au/SiO 2 nanoparticles on a glassy carbon electrode. The resulting electrode (nano-Au/SiO 2 /GCE) was characterized by scanning electronic microscopy, X-ray photoelectron spectroscopy and electrochemical techniques. The electrochemical behavior of dihydronicotinamide adenine dinucleotide (NADH) at the nano-Au/SiO 2 /GCE were thoroughly investigated. Compared to the unmodified electrode, the overpotential decreased by about 300 mV, and the current response significantly increased. These changes indicated that the modified electrode showed excellent catalytic activity in the oxidation of NADH. A linear relationship was obtained in the NADH concentration range from 1. 0 x 10 -6 to 1. 0 x 10 -4 mol L -1 . In addition, amperometric sensing of ethanol at the nano-Au/SiO 2 /GCE in combination with alcohol dehydrogenase and nicotinamide adenine dinucleotide was successfully demonstrated. A wide linear response was also found for ethanol in the range from 5. 0 x 10 -5 to 1. 0 x 10 -3 mol L -1 and 1. 0 x 10 -3 to 1. 0 x 10 -2 mol L -1 , respectively. The method was successfully applied to determine ethanol in beer and biological samples. (author)

Preparation of N-Graphdiyne Nanosheets at Liquid/Liquid Interface for Photocatalytic NADH Regeneration.

Science.gov (United States)

Pan, Qingyan; Liu, Hui; Zhao, Yingjie; Chen, Siqi; Xue, Bo; Kan, Xiaonan; Huang, Xiaowen; Liu, Jian; Li, Zhibo

2018-04-16

Two-dimensional (2D) N-graphdiyne (N-GDY) nanosheets containing different number of N were synthesized by polymerization of triazine, pyrazine, and pyridine-based monomers at liquid/liquid interface. The configurations and nanostructures of N-GDY were well-characterized. The wettability changed to more hydrophilic as the N contents increased. The collected N-GDY was further employed as metal-free photocatalyst for NADH regeneration. The catalytic performance was related with the N content in the graphdiyne. The N3-GDY demonstrated the best activity. This strategy provided a new promising platform of designing unique 2D N-GDY with tunable performance in biorelated catalysis.

Crystallization and preliminary X-ray analysis of the complex of NADH and 3α-hydroxysteroid dehydrogenase from Pseudomonas sp. B-0831

Energy Technology Data Exchange (ETDEWEB)

Kataoka, Sachiyo [Graduate School of Agriculture, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, Kyoto 606-8522 (Japan); Nakamura, Shota; Ohkubo, Tadayasu [Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Ueda, Shigeru [Diagnostics Department, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokuni, Shizuoka 410-2321 (Japan); Uchiyama, Susumu [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Kobayashi, Yuji [Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094 (Japan); Oda, Masayuki, E-mail: oda@kpu.ac.jp [Graduate School of Agriculture, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, Kyoto 606-8522 (Japan)

2006-06-01

The complex of NADH and 3α-HSD from Pseudomonas sp. B-0831 has been crystallized and X-ray diffraction data have been collected to 1.8 Å resolution. The NAD(P){sup +}-dependent enzyme 3α-hydroxysteroid dehydrogenase (3α-HSD) catalyzes the reversible interconversion of hydroxyl and oxo groups at position 3 of the steroid nucleus. The complex of NADH and 3α-HSD from Pseudomonas sp. B-0831 was crystallized by the hanging-drop vapour-diffusion method. Refinement of crystallization conditions with microseeding improved the quality of the X-ray diffraction data to a resolution of 1.8 Å. The crystals belonged to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 62.46, b = 82.25, c = 86.57 Å, and contained two molecules, reflecting dimer formation of 3α-HSD, in the asymmetric unit.

The reaction of NADPH with bovine mitochondrial NADH:ubiquinone oxidoreductase revisited: I. Proposed consequences for electron transfer in the enzyme

NARCIS (Netherlands)

Albracht, S.P.J.

2010-01-01

Bovine NADH:ubiquinone oxidoreductase (Complex I) is the first complex in the mitochondrial respiratory chain. It has long been assumed that it contained only one FMN group. However, as demonstrated in 2003, the intact enzyme contains two FMN groups. The second FMN was proposed to be located in a

Educational Possibilities of Keeping Goats in Elementary Schools in Japan

Science.gov (United States)

Koda, Naoko; Kutsumi, Shiho; Hirose, Toshiya; Watanabe, Gen

2016-01-01

Many Japanese elementary schools keep small animals for educational purposes, and the effects and challenges have been investigated. Although goats are medium-sized animals that are familiar to Japanese, few practical studies have been conducted on keeping goats in schools. This study investigated the effects and challenges of keeping goats in elementary schools and discussed its educational possibilities. A semi-structured interview survey was conducted with 11 personnel that were responsible for keeping goats in 6 elementary schools in urban areas. They described benefits, problems, and tips related to keeping goats. Participant observation was also conducted on daily human–goat interactions in these schools. The results indicated that children in all six grades were able to care for goats. Goats were used for various school subjects and activities. As a result of keeping goats, children developed affection for them, attitude of respect for living things, greater sense of responsibility, and enhanced interpersonal interactional skills. Stronger ties between the schools and parents and community were developed through cooperation in goat-keeping. Some anxieties existed about the risk of injury to children when interacting with goats. Other challenges included the burden of taking care of the goats on holidays and insufficient knowledge about treatment in case of their illness or injury. The results suggested similarities to the benefits and challenges associated with keeping small animals in elementary schools, although the responsibility and the burden on the schools were greater for keeping goats than small animals because of their larger size and the need for children to consider the goats’ inner state and to cooperate with others when providing care. At the same time, goats greatly stimulated interest, cooperation, and empathy in children. Goats can expand educational opportunities and bring about many positive effects on child development. PMID:28083538

Oxidação eletrocatalítica de NADH empregando um novo sensor à base de um complexo macrocíclico n4 sobre grafeno e DNA

OpenAIRE

Ribeiro, Izabela Aparecida Luiz

2015-01-01

Área de concentração: Química Analítica. β-Nicotinamida adenina dinucleotídeo (NADH) e sua forma oxidada correspondente (NAD+) representam uma coenzima de grande importância em centenas de reações naturais catalisadas por enzimas desidrogenase, sendo vitais no metabolismo respiratório mitocondrial por estimular a produção de energia e atuam como principais transportadoras de cargas centrais em células vivas. Por estes motivos, a determinação eletroquímica de NADH tem atraído considerável a...

Modification of an enzyme electrode by electrodeposition of hydroquinone for use as the anode of a glucose fuel cell

Energy Technology Data Exchange (ETDEWEB)

Kuwahara, Takashi; Yamazaki, Hiraku; Kondo, Mizuki [Department of Bioengineering, Faculty of Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka-machi, Nagaoka 940-2188 (Japan); Shimomura, Masato, E-mail: smasato@vos.nagaokaut.ac.jp [Department of Bioengineering, Faculty of Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka-machi, Nagaoka 940-2188 (Japan)

2012-06-15

An electrode having immobilized glucose oxidase (GOx) was modified with polyhydroquinone (PHQ), which was employed as an electron-transferring mediator, by a simple electrochemical method and used as the anode of a glucose fuel cell. The GOx-immobilized electrode was fabricated by attaching polyallylamine (PAAm) and then GOx covalently onto a gold electrode covered with a monolayer formed with 3-mercaptopropionic acid. Subsequently, the GOx-immobilized electrode (GOx/PAAm electrode) was modified with PHQ by electrodeposition of hydroquinone. The cyclic voltammogram of the modified electrode (PHQ/GOx/PAAm electrode) in a phosphate buffer solution (0.10 M, pH 7.0) showed redox peaks due to the electrodeposited PHQ, whereas no redox peaks were found for the GOx/PAAm electrode in the buffer solution containing p-benzoquinone (BQ). The onset potential of glucose oxidation with the PHQ/GOx/PAAm electrode became ca. 0.2 V more negative than that observed with the GOx/PAAm electrode in the presence of BQ. The glucose fuel cell equipped with the PHQ/GOx/PAAm electrode as an anode gave a 3 times larger power output than the cell with the GOx/PAAm electrode using dissolved quinone as the mediator.

Ca2+ dependence of gluconeogenesis stimulation by glucagon at different cytosolic NAD+-NADH redox potentials

Directory of Open Access Journals (Sweden)

Marques-da-Silva A.C.

1997-01-01

Full Text Available The influence of Ca2+ on hepatic gluconeogenesis was measured in the isolated perfused rat liver at different cytosolic NAD+-NADH potentials. Lactate and pyruvate were the gluconeogenic substrates and the cytosolic NAD+-NADH potentials were changed by varying the lactate to pyruvate ratios from 0.01 to 100. The following results were obtained: a gluconeogenesis from lactate plus pyruvate was not affected by Ca2+-free perfusion (no Ca2+ in the perfusion fluid combined with previous depletion of the intracellular pools; gluconeogenesis was also poorly dependent on the lactate to pyruvate ratios in the range of 0.1 to 100; only for a ratio equal to 0.01 was a significantly smaller gluconeogenic activity observed in comparison to the other ratios. b In the presence of Ca2+, the increase in oxygen uptake caused by the infusion of lactate plus pyruvate at a ratio equal to 10 was the most pronounced one; in Ca2+-free perfusion the increase in oxygen uptake caused by lactate plus pyruvate infusion tended to be higher for all lactate to pyruvate ratios; the most pronounced difference was observed for a lactate/pyruvate ratio equal to 1. c In the presence of Ca2+ the effects of glucagon on gluconeogenesis showed a positive correlation with the lactate to pyruvate ratios; for a ratio equal to 0.01 no stimulation occurred, but in the 0.1 to 100 range stimulation increased progressively, producing a clear parabolic dependence between the effects of glucagon and the lactate to pyruvate ratio. d In the absence of Ca2+ the relationship between the changes caused by glucagon in gluconeogenesis and the lactate to pyruvate ratio was substantially changed; the dependence curve was no longer parabolic but sigmoidal in shape with a plateau beginning at a lactate/pyruvate ratio equal to 1; there was inhibition at the lactate to pyruvate ratios of 0.01 and 0.1 and a constant stimulation starting with a ratio equal to 1; for the lactate to pyruvate ratios of 10 and 100

LASL computerized quality assurance record-keeping system for analytical chemistry

International Nuclear Information System (INIS)

Dahlby, J.W.; Phillips, J.R.

1976-06-01

Research programs requiring quality assurance surveillance, certification procedures, and associated record keeping have increased markedly at the Los Alamos Scientific Laboratory. A computer-based system, accessible through time-sharing terminals, performs many routine operations, including continued records updating for equipment calibration, personnel certification, quality assurance procedure listings, and controlled-document distribution lists. The system described has operated successfully for more than a year, resulting in a significant savings in man-hours required to keep quality assurance records

Getting Students in the Journal-Keeping Habit.

Science.gov (United States)

Hildebrandt, Peter

1992-01-01

Discusses the value of journals for understanding a historical period. Suggests that social studies students be encouraged to keep journals to understand better the difference between something written at the time and a later description of the same event. Lists examples of journals from historical periods that may interest students in journal…

Gold electrodes modified with 16H, 18H-dibenzo[c,l]-7,9-dithia-16,18-diazapentacene for electrocatalytic oxidation of NADH

NARCIS (Netherlands)

Rosca, V.; Muresan, L.; Popescu, I.C.; Cristea, C.; Silberg, I.A.

2001-01-01

16H,18H-Dibenzo[c,l]-7,9-dithia-16,18-diazapentacene (DDDP), a new phenothiazine derivative containing two linearly condensed phenothiazine rings, strongly adsorbs on polyoriented gold resulting in a modified electrode with electrocatalytic activity for ß-nicotinamide adenine dinucleotide (NADH)

Intraoperative non-record-keeping usage of anesthesia information management system workstations and associated hemodynamic variability and aberrancies.

Science.gov (United States)

Wax, David B; Lin, Hung-Mo; Reich, David L

2012-12-01

Anesthesia information management system workstations in the anesthesia workspace that allow usage of non-record-keeping applications could lead to distraction from patient care. We evaluated whether non-record-keeping usage of the computer workstation was associated with hemodynamic variability and aberrancies. Auditing data were collected on eight anesthesia information management system workstations and linked to their corresponding electronic anesthesia records to identify which application was active at any given time during the case. For each case, the periods spent using the anesthesia information management system record-keeping module were separated from those spent using non-record-keeping applications. The variability of heart rate and blood pressure were also calculated, as were the incidence of hypotension, hypertension, and tachycardia. Analysis was performed to identify whether non-record-keeping activity was a significant predictor of these hemodynamic outcomes. Data were analyzed for 1,061 cases performed by 171 clinicians. Median (interquartile range) non-record-keeping activity time was 14 (1, 38) min, representing 16 (3, 33)% of a median 80 (39, 143) min of procedure time. Variables associated with greater non-record-keeping activity included attending anesthesiologists working unassisted, longer case duration, lower American Society of Anesthesiologists status, and general anesthesia. Overall, there was no independent association between non-record-keeping workstation use and hemodynamic variability or aberrancies during anesthesia either between cases or within cases. Anesthesia providers spent sizable portions of case time performing non-record-keeping applications on anesthesia information management system workstations. This use, however, was not independently associated with greater hemodynamic variability or aberrancies in patients during maintenance of general anesthesia for predominantly general surgical and gynecologic procedures.

Hydroquinone; A Novel Bioactive Compound from Plant-Derived Smoke Can Cue Seed Germination of Lettuce

Science.gov (United States)

Kamran, Muhammad; Khan, Abdul L.; Ali, Liaqat; Hussain, Javid; Waqas, Muhammad; Al-Harrasi, Ahmed; Imran, Qari M.; Kim, Yoon-Ha; Kang, Sang-Mo; Yun, Byung-Wook; Lee, In-Jung

2017-01-01

Plant-derived smoke has been known to play an important role in distribution and growth of vegetation. Using a proficiently designed furnace, we extracted smoke from the leaves of four plant viz. Helianthus annuus,Aloe vera,Ginkgo biloba, and Cymbopogon jwarancusa. Smoke dilutions obtained from these plants were obtained in different concentrations to identify potential lettuce growth promoting smoke solution. Results revealed that smoke obtained from G. biloba significantly enhanced the lettuce seed germination. This solution was then partitioned into ethyl acetate, dichloromethane, n-hexane, chloroform and ether fractions. Ethyl acetate fraction was found to be potent to enhance seed germination. This fraction was subjected to column chromatography and spectroscopic techniques to obtain compound 1. This compound was identified as hydroquinone using 1D and 2D NMR techniques. At low concentrations (5, 10, and 20 ppm), compound 1 enhanced the lettuce seed germination; however, higher concentrations inhibited its growth as compared to control. PMID:28553632

Hydroquinone; A novel bioactive compound from plant-derived smoke can cue seed germination of lettuce

Science.gov (United States)

Kamran, Muhammad; Khan, Abdul L.; Ali, Liaqat; Hussain, Javid; Waqas, Muhammad; Al-Harrasi, Ahmed; Imran, Qari M.; Kim, Yoon-Ha; Kang, Sang-Mo; Yun, Byung-Wook; Lee, In-Jung

2017-05-01

Plant-derived smoke has been known to play an important role in distribution and growth of vegetation. Using a proficiently designed furnace, we extracted smoke from the leaves of four plant viz. Helianthus annuus, Aloe vera, Ginkgo biloba, and Cymbopogon jwarancusa. Smoke dilutions obtained from these plants were obtained in different concentrations to identify potential lettuce growth promoting smoke solution. Results revealed that smoke obtained from Ginkgo biloba significantly enhanced the lettuce seed germination. This solution was then partitioned into ethyl acetate, dichloromethane, n-hexane, chloroform and ether fractions. Ethyl acetate fraction was found to be potent to enhance seed germination. This fraction was subjected to column chromatography and spectroscopic techniques to obtain compound 1. This compound was identified as hydroquinone using 1D and 2D NMR techniques. At low concentrations (5, 10 and 20 ppm), compound 1 enhanced the lettuce seed germination; however, higher concentrations inhibited its growth as compared to control.

Carbon nanosheets-based supercapacitors: Design of dual redox additives of 1, 4-dihydroxyanthraquinone and hydroquinone for improved performance

Science.gov (United States)

Xu, Dong; Sun, Xiao Na; Hu, Wei; Chen, Xiang Ying

2017-07-01

Using thiocarbanilide and Mg(OH)2 powders as carbon precursor and template, respectively, novel 2D carbon nanosheets with large area have been produced. Next, based on the cooperative effect, 1, 4-dihydroxyanthraquinone (DQ) and hydroquinone (HQ) regarded as efficient dual redox additives have been incorporated into the electrode carbon material and H2SO4 electrolyte, respectively, to largely elevate the capacitive performance of supercapacitors. More importantly, the cooperative effect results from the redox processes of DQ and HQ consecutively occurring in the electrode carbon material and aqueous H2SO4 electrolyte, respectively. Besides, the molar ratio of DQ and HQ exerts a crucial role in the determination of the electrochemical behaviors and eventually the optimum condition is the mass ratio of 1:1 concerning the DQ and porous carbon within solid electrode while retaining the HQ concentration as 20 mmol L-1 in 1 mol L-1 H2SO4 electrolyte. As a result, the maximum specific capacitance is achieved of 239 F g-1 at 3 A g-1, and furthermore the maximum energy density up to 21.1 Wh kg-1 is almost 3.5 times larger than that of the one without introducing any redox additive.

The reaction of NADPH with bovine mitochondrial NADH:ubiquinone oxidoreductase revisited: II. Comparison of the proposed working hypothesis with literature data.

NARCIS (Netherlands)

Albracht, S.P.J.

2010-01-01

The first purification of bovine NADH:ubiquinone oxidoreductase (Complex I) was reported nearly half a century ago (Hatefi et al. J Biol Chem 237:1676-1680, 1962). The pathway of electron-transfer through the enzyme is still under debate. A major obstacle is the assignment of EPR signals to the

The Effect of Tertiary Butyl Hydroquinone on the Biodegradability of Palm Olein

Directory of Open Access Journals (Sweden)

Emmanuel ALUYOR

2009-07-01

Full Text Available Poor oxidative stability is demonstrated by most vegetable oils especially in industrial situations. Antioxidants are widely used for overcoming poor oxidative stability in vegetable oils. The adverse effect of additives on the overall biodegradability of vegetable oil based industrial fluids could however be a concern. Biodegradability provides an indication of the persistence of any particular substance in the environment. The superior biodegradation of vegetable oils in comparison with mineral based oils has been demonstrated severally, leaving scientists with the lone challenge of finding economic and safe means to improve their working efficiency in terms of their poor oxidative stability. This study investigated the extent to which the use of the antioxidant Tertiary butyl hydroquinone (TBHQ in palm olein impaired biodegradability, and described the relationship between antioxidant loading and biodegradability. Increased antioxidant loading resulted in a matching decrease in biodegradability. Using the total cumulative oxygen depletion value of pure refined palm olein at the end of the 28 day period as a standard of comparison, a 0.02% concentration of TBHQ in palm olein resulted in a 25% loss in biodegradability; a 2% concentration of TBHQ resulted in a 56.5% loss in biodegradability. At 6% TBHQ concentration, no biodegradation was observed in the palm olein sample studied.

Brain physiological state evaluated by real-time multiparametric tissue spectroscopy in vivo

Science.gov (United States)

Mayevsky, Avraham; Barbiro-Michaely, Efrat; Kutai-Asis, Hofit; Deutsch, Assaf; Jaronkin, Alex

2004-07-01

The significance of normal mitochondrial function in cellular energy homeostasis as well as its involvement in acute and chronic neurodegenerative disease was reviewed recently (Nicholls & Budd. Physiol Rev. 80: 315-360, 2000). Nevertheless, monitoring of mitochondrial function in vivo and real time mode was not used by many investigators and is very rare in clinical practice. The main principle tool available for the evaluation of mitochondrial function is the monitoring of NADH fluorescence. In order to interpret correctly the changes in NADH redox state in vivo, it is necessary to correlate this signal to other parameters, reflecting O2 supply to the brain. Therefore, we have developed and applied a multiparametric optical monitoring system, by which microcirculatory blood flow and hemoglobin oxygenation is measured, together with mitochondrial NADH fluorescence. Since the calibration of these signals is not in absolute units, the simultaneous monitoring provide a practical tool for the interpretation of brain functional state under various pathophysiological conditions. The monitoring system combines a time-sharing fluorometer-reflectometer for the measurement of NADH fluorescence and hemoglobin oxygenation as well as a laser Doppler flowmeter for the recording of microcirculatory blood flow. A combined fiber optic probe was located on the surface of the brain using a skull cemented cannula. Rats and gerbils were exposed to anoxia, ischemia and spreading depression and the functional state of the brain was evaluated. The results showed a clear correlation between O2 supply/demand as well as, energy balance under the various pathophysiological conditions. This monitoring approach could be adapted to clinical monitoring of tissue vitality.

Streptococcus mutans NADH oxidase lies at the intersection of overlapping regulons controlled by oxygen and NAD+ levels.

Science.gov (United States)

Baker, J L; Derr, A M; Karuppaiah, K; MacGilvray, M E; Kajfasz, J K; Faustoferri, R C; Rivera-Ramos, I; Bitoun, J P; Lemos, J A; Wen, Z T; Quivey, R G

2014-06-01

NADH oxidase (Nox, encoded by nox) is a flavin-containing enzyme used by the oral pathogen Streptococcus mutans to reduce diatomic oxygen to water while oxidizing NADH to NAD(+). The critical nature of Nox is 2-fold: it serves to regenerate NAD(+), a carbon cycle metabolite, and to reduce intracellular oxygen, preventing formation of destructive reactive oxygen species (ROS). As oxygen and NAD(+) have been shown to modulate the activity of the global transcription factors Spx and Rex, respectively, Nox is potentially poised at a critical junction of two stress regulons. In this study, microarray data showed that either addition of oxygen or loss of nox resulted in altered expression of genes involved in energy metabolism and transport and the upregulation of genes encoding ROS-metabolizing enzymes. Loss of nox also resulted in upregulation of several genes encoding transcription factors and signaling molecules, including the redox-sensing regulator gene rex. Characterization of the nox promoter revealed that nox was regulated by oxygen, through SpxA, and by Rex. These data suggest a regulatory loop in which the roles of nox in reduction of oxygen and regeneration of NAD(+) affect the activity levels of Spx and Rex, respectively, and their regulons, which control several genes, including nox, crucial to growth of S. mutans under conditions of oxidative stress. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Keeping an eye on the time

NARCIS (Netherlands)

Mariëlle Cloïn; Andries van den Broek; Remko van den Dool a.o.

2013-01-01

Original title: Met het oog op de tijd Like money, we can only spend our time once. Unlike money, however, everyone has precisely the same amount of time at their disposal. Yet there are obviously differences in the way people use their time. This report explores the question of precisely

In-situ quartz crystal microgravimetric studies of molecular adsorbates containing thiol and hydroquinone moieties bound to Au(111) surfaces in aqueous electrolytes

Energy Technology Data Exchange (ETDEWEB)

Mo, Y.; Sukenik, C.; Sandifer, M. [Case Western Univ., Cleveland, OH (United States); Barriga, R.J.; Soriaga, M.P.; Scherson, D. [Texas A& M Univ., College Station, TX (United States)

1995-12-01

The microgravimetric properties of monolayers of 2, 5-dihydroxythiophenol, 2,5-dihydroxybenzyl mercaptan, and 2, 5-dihydroxy-4-methylbenzyl mercaptan adsorbed on Au(111) single crystal electrodes were examined by in situ quartz crystal microbalance techniques in aqueous perchloric acid electrolytes. The results obtained are consistent with the reversible loss of an average of about three waters per adsorbed molecule as the layers are oxidized and subsequently reduced. These observations provide evidence for discrete changes in the extent of bound water within the hydroquinone/quinone layer as the oxidation state of the monolayer is changed. 9 refs., 4 figs.

Keeping Up: Personal Staff Development

Science.gov (United States)

Woolls, Blanche

2009-01-01

Some essential components of "keeping current" with trends and new developments in the school library field for library media specialists includes attending conferences and reading professional literature. Beginning in May 2007, one article on "keeping up" each year has been devoted to summarizing the major themes in conferences and professional…

A novel nine base deletion mutation in NADH-cytochrome b5 reductase gene in an Indian family with recessive congenital methemoglobinemia-type-II

Directory of Open Access Journals (Sweden)

Prashant Warang

2015-12-01

Full Text Available Recessive hereditary methemoglobinemia (RCM associated with severe neurological abnormalities is a very rare disorder caused by NADH- cytochrome b5 reductase (cb5r deficiency (Type II. We report a case of 11 month old male child who had severe mental retardation, microcephaly and gross global developmental delay with methemoglobin level of 61.1%. The diagnosis of NADH-CYB5R3 deficiency was made by the demonstration of significantly reduced NADH-CYB5R3 activity in the patient and intermediate enzyme activity in both the parents. Mutation analysis of the CYB5R gene revealed a novel nine nucleotide deletion in exon 6 leading to the elimination of 3 amino acid residues (Lys173, Ser174 and Val 175. To confirm that this mutation was not an artifact, we performed PCR-RFLP analysis using the restriction enzyme Drd I. As the normal sequence has a restriction recognition site for Drd I which was eliminated by the deletion, a single band of 603-bp was seen in the presence of the homozygous mutation. Molecular modeling analysis showed a significant effect of these 3 amino acids deletion on the protein structure and stability leading to a severe clinical presentation. A novel homozygous 9 nucleotide deletion (p.K173–p.V175del3 is shown to be segregated with the disease in this family. Knowing the profile of mutations would allow us to offer prenatal diagnosis in families with severe neurological disorders associated with RCM — Type II.

Cooperative Electrocatalytic O ₂ Reduction Involving Co(salophen) with p- Hydroquinone as an Electron–Proton Transfer Mediator

Energy Technology Data Exchange (ETDEWEB)

Anson, Colin W. [Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States; Stahl, Shannon S. [Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States

2017-12-01

The molecular cobalt complex, Co(salophen), and para-hydroquinone (H2Q) serve as effective cocatalysts for the electrochemical reduction of O2 to water. Mechanistic studies reveal redox cooperativity between Co(salophen) and H2Q. H2Q serves as an electron-proton transfer mediator (EPTM) that enables electrochemical O2 reduction at higher potentials and with faster rates than is observed with Co(salophen) alone. Replacement of H2Q with the higher potential EPTM, 2-chloro-H2Q, allows for faster O2 reduction rates at higher applied potential. These results demonstrate a unique strategy to achieve improved performance with molecular electrocatalyst systems.

Major KEEP Findings, 1971 - 1975.

Science.gov (United States)

Kamehameha Schools, Honolulu, HI. Kamehameha Early Education Project.

This report lists the 34 major research findings from the Kamehameha Early Education Program (KEEP) for the years 1971-1975. Each finding is accompanied by a listing of KEEP technical reports and working papers which contain information relevant to that finding. Included among areas covered in the findings are: (1) student motivation, (2) teacher…

KEEP Five-Year Summary Report.

Science.gov (United States)

Gallimore, Ronald; Tharp, Roland G.

This brief summary outlines the activities and findings of the research and development efforts of the Kamehameha Early Education Program (KEEP) from 1971 to 1976. The paper suggests that the original goals of the program were met and that the initial operating procedures agreed upon by KEEP and the Hawaii State Department of Education were…

Keep Kids' Mouths Healthy: Brush 2min2X

Science.gov (United States)

Make sure your kids brush for 2 minutes, twice a day. En Español facebook twitter instagram Kids’ Healthy Mouths Health Watch & Brush! Watch ... About Kids’ Teeth Teeth Helpful Resources Links Keep Kids’ Mouths Healthy Roll over or click the time ...

Keeping Pace with K-12 Online Learning, 2016

Science.gov (United States)

Gemin, Butch; Pape, Larry

2017-01-01

"Keeping Pace with K-12 Online Learning 2016" marks the thirteenth consecutive year Evergreen has published its annual research of the K-12 education online learning market. The thirteen years of researching, writing and publishing this report represents a time of remarkable change. There has been a constant presence that has become the…

Effects of exogenous vitamins A, C, and E and NADH supplementation on proliferation, cytokines release, and cell redox status of lymphocytes from healthy aged subjects.

Science.gov (United States)

Bouamama, Samia; Merzouk, Hafida; Medjdoub, Amel; Merzouk-Saidi, Amel; Merzouk, Sid Ahmed

2017-06-01

Aging is an inevitable biological event that is associated with immune alterations. These alterations are related to increased cellular oxidative stress and micronutrient deficiency. Antioxidant supplementation could improve these age-related abnormalities. The aim of this study was to determine in vitro effects of vitamin A, vitamin C, vitamin E, and nicotinamide adenine dinucleotide (NADH) on T cell proliferation, cytokine release, and cell redox status in the elderly compared with young adults. Peripheral blood lymphocytes were isolated using a density gradient of Histopaque. They were cultured in vitro and stimulated with concanavalin A in the presence or absence of vitamins. Cell proliferation was determined by conducting MTT assays, and based on interleukin-2 and interleukin-4 secretions. Cell oxidant/antioxidant balance was assessed by assaying reduced glutathione (GSH), malondialdehyde, carbonyl protein levels, and catalase activity. The present study demonstrated that T-lymphocyte proliferation was decreased with aging and was associated with cytokine secretion alterations, GSH depletion, and intracellular oxidative stress. In the elderly, vitamin C, vitamin E, and NADH significantly improved lymphocyte proliferation and mitigated cellular oxidative stress, whereas vitamin A did not affect cell proliferation or cell redox status. In conclusion, vitamin C, vitamin E, and NADH supplementation improved T-lymphocytes response in the elderly, and could contribute to the prevention of age-related immune alterations. Consumption of food items containing these vitamins is recommended, and further investigation is necessary to evaluate the effect of vitamin supplementation in vivo.

Identification of the para-nitrophenol catabolic pathway, and characterization of three enzymes involved in the hydroquinone pathway, in pseudomonas sp. 1-7

Directory of Open Access Journals (Sweden)

Zhang Shuangyu

2012-03-01

Full Text Available Abstract Background para-Nitrophenol (PNP, a priority environmental pollutant, is hazardous to humans and animals. However, the information relating to the PNP degradation pathways and their enzymes remain limited. Results Pseudomonas sp.1-7 was isolated from methyl parathion (MP-polluted activated sludge and was shown to degrade PNP. Two different intermediates, hydroquinone (HQ and 4-nitrocatechol (4-NC were detected in the catabolism of PNP. This indicated that Pseudomonas sp.1-7 degraded PNP by two different pathways, namely the HQ pathway, and the hydroxyquinol (BT pathway (also referred to as the 4-NC pathway. A gene cluster (pdcEDGFCBA was identified in a 10.6 kb DNA fragment of a fosmid library, which cluster encoded the following enzymes involved in PNP degradation: PNP 4-monooxygenase (PdcA, p-benzoquinone (BQ reductase (PdcB, hydroxyquinol (BT 1,2-dioxygenase (PdcC, maleylacetate (MA reductase (PdcF, 4-hydroxymuconic semialdehyde (4-HS dehydrogenase (PdcG, and hydroquinone (HQ 1,2-dioxygenase (PdcDE. Four genes (pdcDEFG were expressed in E. coli and the purified pdcDE, pdcG and pdcF gene products were shown to convert HQ to 4-HS, 4-HS to MA and MA to β-ketoadipate respectively by in vitro activity assays. Conclusions The cloning, sequencing, and characterization of these genes along with the functional PNP degradation studies identified 4-NC, HQ, 4-HS, and MA as intermediates in the degradation pathway of PNP by Pseudomonas sp.1-7. This is the first conclusive report for both 4-NC and HQ- mediated degradation of PNP by one microorganism.

Keep online应用趋势预测

Institute of Scientific and Technical Information of China (English)

谢剑超

2010-01-01

@@ 随着执智能机的普及和上网资费下降,用户逐渐形成了keep online的使用习惯.保持在线是现在智能终端的最主要的特点. Keep online不是always oline,keep online 表示用户保持在线,而不指用户一直使用应用.Keep lnline 并不代表用户使用应用的时间变长,而是指用户使用应用更加频繁.

Resolution of NADH:ubiquinone oxidoreductase from bovine heart mitochondria into two subcomplexes, one of which contains the redox centers of the enzyme.

Science.gov (United States)

Finel, M; Skehel, J M; Albracht, S P; Fearnley, I M; Walker, J E

1992-11-24

NADH:ubiquinone oxidoreductase (complex I) was purified from bovine heart mitochondria by solubilization with n-dodecyl beta-D-maltoside (lauryl maltoside), ammonium sulfate fractionation, and chromatography on Mono Q in the presence of the detergent. Its subunit composition was very similar to complex I purified by conventional means. Complex I was dissociated in the presence of N,N-dimethyldodecylamine N-oxide and beta-mercaptoethanol, and two subcomplexes, I alpha and I beta, were isolated by chromatography. Subcomplex I alpha catalyzes electron transfer from NADH to ubiquinone-1. It is composed of about 22 different and mostly hydrophilic subunits and contains 2.0 nmol of FMN/mg of protein. Among its subunits is the 51-kDa subunit, which binds FMN and NADH and probably contains a [4Fe-4S] cluster also. Three other potential Fe-S proteins, the 75- and 24-kDa subunits and a 23-kDa subunit (N-terminal sequence TYKY), are also present. All of the Fe-S clusters detectable by EPR in complex I, including cluster 2, are found in subcomplex I alpha. The line shapes of the EPR spectra of the Fe-S clusters are slightly broadened relative to spectra measured on complex I purified by conventional means, and the quinone reductase activity is insensitive to rotenone. Similar changes were found in samples of the intact chromatographically purified complex I, or in complex I prepared by the conventional method and then subjected to chromatography in the presence of lauryl maltoside. Subcomplex I beta contains about 15 different subunits. The sequences of many of them contain hydrophobic segments that could be membrane spanning, including at least two mitochondrial gene products, ND4 and ND5. The role of subcomplex I beta in the intact complex remains to be elucidated.

Simultaneous Determination of Hydroquinone, Catechol and Resorcinol at Graphene Doped Carbon Ionic Liquid Electrode

Directory of Open Access Journals (Sweden)

Li Ma

2012-01-01

Full Text Available A new composite electrode has been prepared with doping graphene into the paste consisting graphite and ionic liquid, n-octyl-pyridinum hexafluorophosphate (OPFP. This electrode shows an excellent electrochemical activity for the redox of hydroquinone (HQ, catechol (CC, and resorcinol (RS. In comparison with bare paste electrode, the redox peaks of three isomers of dihydroxybenzene can be obviously, simultaneously observed at graphene doping paste electrode. Under the optimized condition, the simultaneous determination of HQ, CC, and RS in their ternary mixture can be carried out with a differential pulse voltammetric technique. The peak currents are linear to the concentration of HQ, CC, and RS in the range form 1×10−5 to 4×10−4, 1×10−5 to 3×10−4, and 1×10−6 to 1.7×10−4 mol L−1, respectively. The limits of detection are 1.8×10−6 mol L−1 for HQ, 7.4×10−7 mol L−1 for CC, and 3.6×10−7 M for RS, respectively.

Dual emission fluorescent silver nanoclusters for sensitive detection of the biological coenzyme NAD+/NADH.

Science.gov (United States)

Yuan, Yufeng; Huang, Kehan; Chang, Mengfang; Qin, Cuifang; Zhang, Sanjun; Pan, Haifeng; Chen, Yan; Xu, Jianhua

2016-02-01

Fluorescent silver nanoclusters (Ag NCs) displaying dual-excitation and dual-emission properties have been developed for the specific detection of NAD(+) (nicotinamide adenine dinucleotide, oxidized form). With the increase of NAD(+) concentrations, the longer wavelength emission (with the peak at 550 nm) was gradually quenched due to the strong interactions between the NAD(+) and Ag NCs, whereas the shorter wavelength emission (peaking at 395 nm) was linearly enhanced. More important, the dual-emission intensity ratio (I395/I550), fitting by a single-exponential decay function, can efficiently detect various NAD(+) levels from 100 to 4000 μM, as well as label NAD(+)/NADH (reduced form of NAD) ratios in the range of 1-50. Copyright © 2015 Elsevier Inc. All rights reserved.

7 CFR 3200.9 - Accountability and record keeping.

Science.gov (United States)

2010-01-01

... 7 Agriculture 15 2010-01-01 2010-01-01 false Accountability and record keeping. 3200.9 Section... TRANSFER OF EXCESS PERSONAL PROPERTY § 3200.9 Accountability and record keeping. USDA requires that Federal... accountability and record keeping systems. ...

Exploring the economic consequences of paying a supplier to keep a reserve inventory

DEFF Research Database (Denmark)

Abginehchi, Soheil; Larsen, Christian; Thorstenson, Anders

basis, most often only once per month. In addition lead-times are long, as the suppliers are situated overseas.  Therefore the company must keep all the inventories at considerable costs. The company wishes to make contracts with its suppliers such that they keep some reserve inventory that can...... be accessed (at a higher unit price than the normal one) but also with a shorter lead-time. Furthermore the company must also pay a cost proportional to inventory level for maintaining this reserve inventory. This problem can be considered as an inventory control model with two suppliers. We propose a dynamic......This work inspired by a contact with a larger telecommunication company. Many of the products offered are unique for this company and they also have very short lifetimes, normally about 18 months. Furthermore the suppliers do not wish to keep any inventories and they only accept orders on periodic...

The Safety and Efficacy of Treatment With a 1,927-nm Diode Laser With and Without Topical Hydroquinone for Facial Hyperpigmentation and Melasma in Darker Skin Types.

Science.gov (United States)

Vanaman Wilson, Monique J; Jones, Isabela T; Bolton, Joanna; Larsen, Lisa; Fabi, Sabrina Guillen

2018-04-13

The nonablative, fractional, 1,927-nm diode laser is theoretically a safe and effective treatment for hyperpigmentation and melasma in darker skin and may potentiate topical cosmeceutical delivery. To evaluate the use of a nonablative, fractional, 1,927-nm diode laser with and without topical 2% hydroquinone (HQ) cream for moderate-to-severe facial hyperpigmentation in Fitzpatrick skin Types III-V. Forty adults underwent 4 laser treatments at 2-week intervals and were randomized to daily application of 2% HQ cream or moisturizer. Follow-ups were conducted 4 and 12 weeks after the final laser treatment. Hydroquinone and moisturizer groups demonstrated Mottled Pigmentation Area and Severity Index improvements of approximately 50% at post-treatment Weeks 4 and 12. Blinded investigator-assessed hyperpigmentation and photodamage improved significantly for both the groups at post-treatment Weeks 4 and 12. Subject satisfaction improved significantly in both the groups by post-treatment Week 4. Although investigator-rated Global Aesthetic Improvement Scale scores were significantly better in the HQ group at post-treatment Week 12, satisfaction was higher among those using moisturizer. No adverse events were noted. The nonablative, fractional, 1,927-nm diode laser produced significant improvement in hyperpigmentation in Fitzpatrick skin Types III-V by 4 weeks, with maintenance of results at 12 weeks after treatment even without HQ.

Biophysical radiosensitization

International Nuclear Information System (INIS)

Vladescu, C.; Apetroae, M.

1983-01-01

Experimental studies on normal and tumor-bearing rats revealed that chronic treatment with hydroquinone (5 mg/kg/day) inhibited catalase activity in liver, spleen, blood, and H 18R tumor. 3 H-hydroquinone (1.5 μCi/g body weight) showed tumor specificity, with maximum radioactivity in the tumor at 1 h after administration. The biological half-time of 3 H-hydroquinone in the tumor was 2 h, but there seems to exist a longer component, since 24 h after administration, some 30% of the maximum radioactivity could be detected in the tumor. Hydroquinone treatment produces a specific inhibition of catalase in the tumor and a higher degree of oxygenation at this level. These findings support the assumption that the mechanism of action of hydroquinone as an anticancer agent is achieved mainly via peroxide production. The oxygenation of the hypoxic tumoral tissue is done at non-toxic levels of hydroquinone, through a natural and specific biophysical pathway, recommanding hydroquinone for combined anticancer treatment (radiotherapy and chemotherapy). (orig.)

40 CFR 1051.350 - What records must I keep?

Science.gov (United States)

2010-07-01

... CONTROLS CONTROL OF EMISSIONS FROM RECREATIONAL ENGINES AND VEHICLES Testing Production-Line Vehicles and... section. We may review your records at any time. (b) Keep paper or electronic records of your production... production-line vehicles or engines. (2) The names of supervisors involved in each test. (3) The name of...

A complicated biocomputing system based on multi-responsive P(NIPAM-co-APBA) copolymer film electrodes and electrocatalysis of NADH.

Science.gov (United States)

Liang, Jiying; Yu, Xue; Yang, Tiangang; Li, Menglu; Shen, Li; Jin, Yue; Liu, Hongyun

2017-08-23

In this paper, poly(N-isopropylacrylamide-co-3-aminophenylboronic acid) (P(NIPAM-co-APBA)) copolymer films were successfully electropolymerized on the Au electrode surface. The electroactive probe ferrocene carboxylic acid (FCA) in solution showed reversible thermal-, glucose- and pH-responsive on-off cyclic voltammetric (CV) behaviors at the film electrodes. The comparative experiments demonstrated that the thermo-responsive property of the film electrode was ascribed to the PNIPAM component of the films, whereas the glucose- and pH-sensitive behaviors came from the PAPBA constituent. The reduced form of nicotinamide adenine dinucleotide (NADH) could be electrocatalytically oxidized by FCA at the film electrodes, which would greatly amplify the multi-responsive CV signal difference between the on and off states. On the basis of these results, a binary 4-input/4-output logic circuit was fabricated with temperature, glucose, pH and NADH as inputs and the CV responses at 4 different levels as outputs. Moreover, a ternary CONSENSUS logic circuit was established on the same platform, which was the first report on the combination of ternary logic gate and bioelectrocatalysis without using enzymes. This work provided a novel idea for constructing complicated biocomputing systems by increasing the number of inputs/outputs with multi-sensitive interfaces and by designing new types of multi-valued logic gates on the basis of bioelectrocatalysis.

A water-forming NADH oxidase from Lactobacillus pentosus and its potential application in the regeneration of synthetic biomimetic cofactors

Directory of Open Access Journals (Sweden)

Claudia eNowak

2015-09-01

Full Text Available The cell-free biocatalytic production of fine chemicals by oxidoreductases has continuously grown over the past years. Since especially dehydrogenases depend on the stoichiometric use of nicotinamide pyridine cofactors, an integrated efficient recycling system is crucial to allow process operation under economic conditions. Lately, the variety of cofactors for biocatalysis was broadened by the utilization of totally synthetic and cheap biomimetics. Though, to date the regeneration has been limited to chemical or electrochemical methods. Here, we report an enzymatic recycling by the flavoprotein NADH-oxidase from Lactobacillus pentosus (LpNox. Since this enzyme has not been described before, we first characterized it in regard to its optimal reaction parameters. We found that the heterologously overexpressed enzyme only contained 13 % FAD. In vitro loading of the enzyme with FAD, resulted in a higher specific activity towards its natural cofactor NADH as well as different nicotinamide derived biomimetics. Apart from the enzymatic recycling, which gives water as a by-product by transferring four electrons onto oxygen, unbound FAD can also catalyse the oxidation of biomimetic cofactors. Here a two electron process takes place yielding H2O2 instead. The enzymatic and chemical recycling was compared in regard to reaction kinetics for the natural and biomimetic cofactors. With LpNox and FAD, two recycling strategies for biomimetic cofactors are described with either water or hydrogen peroxide as a by-product.

Regulation of expression of Na+ -translocating NADH:quinone oxidoreductase genes in Vibrio harveyi and Klebsiella pneumoniae.

Science.gov (United States)

Fadeeva, Maria S; Yakovtseva, Evgenia A; Belevich, Galina A; Bertsova, Yulia V; Bogachev, Alexander V

2007-10-01

The expression of genes encoding sodium-translocating NADH:quinone oxidoreductase (Na(+)-NQR) was studied in the marine bacterium Vibrio harveyi and in the enterobacterium Klebsiella pneumoniae. It has been shown that such parameters as NaCl concentration, pH value, and presence of an uncoupler in the growth media do not influence significantly the level of nqr expression. However, nqr expression depends on the growth substrates used by these bacteria. Na(+)-NQR is highly repressed in V. harveyi during anaerobic growth, and nqr expression is modulated by electron acceptors and values of their redox potentials. The latter effect was shown to be independent of the ArcAB regulatory system.

Community Perspective of Alternative Methods of keeping ...

African Journals Online (AJOL)

UNIBEN

methods of keeping childhood immunization records based on community's .... An alternative home-based record keeping ... coded before computer entry. Data was managed using the Statistical ..... encounter and also work to ensure accurate.

Methionine – Au Nanoparticle Modified Glassy Carbon Electrode: a Novel Platform for Electrochemical Detection of Hydroquinone

Directory of Open Access Journals (Sweden)

Jiahong HE

2014-12-01

Full Text Available A high sensitive electrochemical sensor based on methionine/gold nanoparticles (MET/AuNPs modified glassy carbon electrode (GCE was fabricated for the quantitative detection of hydroquinone (HQ. The as-modified electrode was characterized by scanning electron microscopy (SEM and X-ray diffraction (XRD techniques. The electrochemical performance of the sensor to HQ was investigated by using cyclic and differential pulse voltammetry, which revealed its excellent electrocatalytic activity and reversibility towards HQ. The separation of anodic and cathodic peak (∆Ep was decreased from 471 mV to 75 mV. The anodic peak current achieved under the optimum conditions was linear with the HQ concentration ranging from 8 μM to 400 μM with the detection limit 0.12 μM (3σ. The as-fabricated sensor also showed a good selectivity towards HQ without demonstrating interference from other coexisting species. Furthermore, the sensor showed a good performance for HQ detection in environmental water, which suggests its potential practical application. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6477

Keeping Food Safe

Centers for Disease Control (CDC) Podcasts

2009-05-27

This CDC Kidtastics podcast discusses things kids and parents can do to help prevent illness by keeping food safe.  Created: 5/27/2009 by National Center for Zoonotic, Vector-Borne, and Enteric Diseases (NCZVED).   Date Released: 5/27/2009.

A highly sensitive NADH sensor based on a mycelium-like nanocomposite using graphene oxide and multi-walled carbon nanotubes to co-immobilize poly(luminol) and poly(neutral red) hybrid films.

Science.gov (United States)

Chiang Lin, Kuo; Yu Lai, Szu; Ming Chen, Shen

2014-08-21

Hybridization of poly(luminol) (PLM) and poly(neutral red) (PNR) has been successfully performed and further enhanced by a conductive and steric hybrid nanotemplate using graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs). The morphology of the PLM-PNR-MWCNT-GO mycelium-like nanocomposite is studied by SEM and AFM and it is found to be electroactive, pH-dependent, and stable in the electrochemical system. It shows electrocatalytic activity towards NADH with a high current response and low overpotential. Using amperometry, it has been shown to have a high sensitivity of 288.9 μA mM(-1) cm(-2) to NADH (Eapp. = +0.1 V). Linearity is estimated in a concentration range of 1.33 × 10(-8) to 1.95 × 10(-4) M with a detection limit of 1.33 × 10(-8) M (S/N = 3). Particularly, it also shows another linear range of 2.08 × 10(-4) to 5.81 × 10(-4) M with a sensitivity of 151.3 μA mM(-1) cm(-2). The hybridization and activity of PLM and PNR can be effectively enhanced by MWCNTs and GO, resulting in an active hybrid nanocomposite for determination of NADH.

Record Keeping Guidelines

Science.gov (United States)

American Psychologist, 2007

2007-01-01

These guidelines are designed to educate psychologists and provide a framework for making decisions regarding professional record keeping. State and federal laws, as well as the American Psychological Association's "Ethical Principles of Psychologists and Code of Conduct," generally require maintenance of appropriate records of psychological…

Young children mostly keep, and expect others to keep, their promises.

Science.gov (United States)

Kanngiesser, Patricia; Köymen, Bahar; Tomasello, Michael

2017-07-01

Promises are speech acts that create an obligation to do the promised action. In three studies, we investigated whether 3- and 5-year-olds (N=278) understand the normative implications of promising in prosocial interactions. In Study 1, children helped a partner who promised to share stickers. When the partner failed to uphold the promise, 3- and 5-year-olds protested and referred to promise norms. In Study 2, when children in this same age range were asked to promise to continue a cleaning task-and they agreed-they persisted longer on the task and mentioned their obligation more frequently than without such a promise. They also persisted longer after a promise than after a cleaning reminder (Study 3). In prosocial interactions, thus, young children feel a normative obligation to keep their promises and expect others to keep their promises as well. Copyright © 2017 Elsevier Inc. All rights reserved.

Marine hydroquinone zonarol prevents inflammation and apoptosis in dextran sulfate sodium-induced mice ulcerative colitis.

Directory of Open Access Journals (Sweden)

Sohsuke Yamada

Full Text Available We previously identified an anti-inflammatory compound, zonarol, a hydroquinone isolated from the brown algae Dictyopteris undulata as a marine natural product. To ascertain the in vivo functions of zonarol, we examined the pharmacological effects of zonarol administration on dextran sulfate sodium (DSS-induced inflammation in a mouse model of ulcerative colitis (UC. Our goal is to establish a safe and effective cure for inflammatory bowel disease (IBD using zonarol.We subjected Slc:ICR mice to the administration of 2% DSS in drinking water for 14 days. At the same time, 5-aminosalicylic acid (5-ASA at a dose of 50 mg/kg (positive control and zonarol at doses of 10 and 20 mg/kg, were given orally once a day. DSS-treated animals developed symptoms similar to those of human UC, such as severe bloody diarrhea, which were evaluated by the disease activity index (DAI. Treatment with 20 mg/kg of zonarol, as well as 5-ASA, significantly suppressed the DAI score, and also led to a reduced colonic ulcer length and/or mucosal inflammatory infiltration by various immune cells, especially macrophages. Zonarol treatment significantly reduced the expression of pro-inflammatory signaling molecules, and prevented the apoptosis of intestinal epithelial cells. Finally, zonarol protected against in vitro lipopolysaccharide (LPS-induced activation in the RAW264.7 mouse macrophage cell line.This is the first report that a marine bioproduct protects against experimental UC via the inhibition of both inflammation and apoptosis, very similar to the standard-of-care sulfasalazine, a well-known prodrug that releases 5-ASA. We believe that the oral administration of zonarol might offer a better treatment for human IBDs than 5-ASA, or may be useful as an alternative/additive therapeutic strategy against UC, without any evidence of side effects.

Host cell and expression engineering for development of an E. coli ketoreductase catalyst: Enhancement of formate dehydrogenase activity for regeneration of NADH

Directory of Open Access Journals (Sweden)

Mädje Katharina

2012-01-01

Full Text Available Abstract Background Enzymatic NADH or NADPH-dependent reduction is a widely applied approach for the synthesis of optically active organic compounds. The overall biocatalytic conversion usually involves in situ regeneration of the expensive NAD(PH. Oxidation of formate to carbon dioxide, catalyzed by formate dehydrogenase (EC 1.2.1.2; FDH, presents an almost ideal process solution for coenzyme regeneration that has been well established for NADH. Because isolated FDH is relatively unstable under a range of process conditions, whole cells often constitute the preferred form of the biocatalyst, combining the advantage of enzyme protection in the cellular environment with ease of enzyme production. However, the most prominent FDH used in biotransformations, the enzyme from the yeast Candida boidinii, is usually expressed in limiting amounts of activity in the prime host for whole cell biocatalysis, Escherichia coli. We therefore performed expression engineering with the aim of enhancing FDH activity in an E. coli ketoreductase catalyst. The benefit resulting from improved NADH regeneration capacity is demonstrated in two transformations of technological relevance: xylose conversion into xylitol, and synthesis of (S-1-(2-chlorophenylethanol from o-chloroacetophenone. Results As compared to individual expression of C. boidinii FDH in E. coli BL21 (DE3 that gave an intracellular enzyme activity of 400 units/gCDW, co-expression of the FDH with the ketoreductase (Candida tenuis xylose reductase; XR resulted in a substantial decline in FDH activity. The remaining FDH activity of only 85 U/gCDW was strongly limiting the overall catalytic activity of the whole cell system. Combined effects from increase in FDH gene copy number, supply of rare tRNAs in a Rosetta strain of E. coli, dampened expression of the ketoreductase, and induction at low temperature (18°C brought up the FDH activity threefold to a level of 250 U/gCDW while reducing the XR activity by

Redox specificity of 2-hydroxyacid-coupled NAD(+/NADH dehydrogenases: a study exploiting "reactive" arginine as a reporter of protein electrostatics.

Directory of Open Access Journals (Sweden)

Pooja Gupta

Full Text Available With "reactive" arginine as a kinetic reporter, 2-hydroxyacid dehydrogenases are assessed in basis of their specialization as NAD(+-reducing or NADH-oxidizing enzymes. Specifically, M4 and H4 lactate dehydrogenases (LDHs and cytoplasmic and mitochondrial malate dehydrogenases (MDHs are compared to assess if their coenzyme specificity may involve electrostatics of cationic or neutral nicotinamide structure as the basis. The enzymes from diverse eukaryote and prokaryote sources thus are assessed in "reactivity" of functionally-critical arginine as a function of salt concentration and pH. Electrostatic calculations were performed on "reactive" arginines and found good correspondence with experiment. The reductive and oxidative LDHs and MDHs are assessed in their count over ionizable residues and in placement details of the residues in their structures as proteins. The variants found to be high or low in ΔpKa of "reactive" arginine are found to be also strong or weak cations that preferentially oxidize NADH (neutral nicotinamide structure or reduce NAD(+ (cationic nicotinamide structure. The ionized groups of protein structure may thus be important to redox specificity of the enzyme on basis of electrostatic preference for the oxidized (cationic nicotinamide or reduced (neutral nicotinamide coenzyme. Detailed comparisons of isozymes establish that the residues contributing in their redox specificity are scrambled in structure of the reductive enzyme.

Keeping a Laboratory Notebook.

Science.gov (United States)

Eisenberg, Anne

1982-01-01

Since the keeping of good records is essential in the chemistry laboratory, general guidelines for maintaining a laboratory notebook are provided. Includes rationale for having entries documented or witnessed. (Author/JN)

Simultaneous determination of some dihydroxybenzenesulphonic acid derivatives and their degradation product and main impurity (hydroquinone) by ion-pair liquid chromatography.

Science.gov (United States)

Tolba, M M

2014-11-01

A simple and sensitive high-performance liquid chromatography method was developed and validated for the determination of calcium dobesilate (DOB) or ethamsylate (ETM) in the presence of their degradation product, hydroquinone (HQ). The analyses were carried out on Promosil C18 column (4.6 mM × 250 mM, 5 µm particle size) using an ion-pair mobile phase consisting of methanol-1.5 mM tetra-butyl ammonium bromide in 0.06 M phosphate buffer (25 : 75, v/v) at pH 6.0 with fluorescence detection at 286/333 nm. Pindolol was used as an internal standard. The proposed method was found to be rectilinear over the concentration ranges of 0.05-0.5 µg/mL for DOB, 0.1-0.8 µg/mL for ETM and 0.005-0.1 µg/mL for HQ. The method was applied for the determination of the studied drugs in different dosage forms and biological fluids. The results of the proposed method were statistically compared with those obtained by the comparison methods revealing no significance differences in the performance of the methods regarding accuracy and precision. Moreover, applying a time-programmed fluorescence technique was valuable for the detection of trace amounts of HQ as an impurity and allowed purity testing of ETM or DOB within the BP pharmacopeial limit (0.1%). Copyright © 2013 John Wiley & Sons, Ltd.

Suggestions of keeping L2 motivation

Institute of Scientific and Technical Information of China (English)

徐斌

2014-01-01

How will we keep the motivation during the second language as long as we can, which confuses us, though what the L2 motivation is and how it is developed have been discussed by the psychologists, educators, etc. The aim of this passage is to clarify the basic content of motivation, including the definition, classification, importance, etc. how the current situation is in se-nior high students’English learning motivation, what should be done to keep such motivation. In the following part, it will be read that the introduction, the chapter stating the content and classification of (L 2) motivation, the chapter analyzing the necessity and state of L2 motivation at senor high, the chapter offering approach to keep that motivation, and the conclusion. All of them use the comparison, explanation and cites.

A comprehensive audit of nursing record keeping practice.

Science.gov (United States)

Griffiths, Paul; Debbage, Samantha; Smith, Alison

Good quality record keeping is essential to safe and effective patient care. To ensure that high standards of record keeping are maintained, regular clinical audit should be undertaken. This article describes an audit and re-audit of nursing record keeping at Sheffield Teaching Hospital NHS Foundation Trust. The article demonstrates improving audit data in 2005 and 2006 and describes how audit and the resulting recommendations and action plans can result in real improvements in the quality of record keeping. The keys to success in this ongoing audit programme are identified as stakeholder involvement, support from the senior nurses in the organization and the use of the data for both local and trust-wide purposes.

Crystal Structure of Saccharomyces cerevisiae ECM4, a Xi-Class Glutathione Transferase that Reacts with Glutathionyl-(hydroquinones.

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Mathieu Schwartz

Full Text Available Glutathionyl-hydroquinone reductases (GHRs belong to the recently characterized Xi-class of glutathione transferases (GSTXs according to unique structural properties and are present in all but animal kingdoms. The GHR ScECM4 from the yeast Saccharomyces cerevisiae has been studied since 1997 when it was found to be potentially involved in cell-wall biosynthesis. Up to now and in spite of biological studies made on this enzyme, its physiological role remains challenging. The work here reports its crystallographic study. In addition to exhibiting the general GSTX structural features, ScECM4 shows extensions including a huge loop which contributes to the quaternary assembly. These structural extensions are probably specific to Saccharomycetaceae. Soaking of ScECM4 crystals with GS-menadione results in a structure where glutathione forms a mixed disulfide bond with the cysteine 46. Solution studies confirm that ScECM4 has reductase activity for GS-menadione in presence of glutathione. Moreover, the high resolution structures allowed us to propose new roles of conserved residues of the active site to assist the cysteine 46 during the catalytic act.

Aspartic acid 397 in subunit B of the Na+-pumping NADH:quinone oxidoreductase from Vibrio cholerae forms part of a sodium-binding site, is involved in cation selectivity, and affects cation-binding site cooperativity.

Science.gov (United States)

Shea, Michael E; Juárez, Oscar; Cho, Jonathan; Barquera, Blanca

2013-10-25

The Na(+)-pumping NADH:quinone complex is found in Vibrio cholerae and other marine and pathogenic bacteria. NADH:ubiquinone oxidoreductase oxidizes NADH and reduces ubiquinone, using the free energy released by this reaction to pump sodium ions across the cell membrane. In a previous report, a conserved aspartic acid residue in the NqrB subunit at position 397, located in the cytosolic face of this protein, was proposed to be involved in the capture of sodium. Here, we studied the role of this residue through the characterization of mutant enzymes in which this aspartic acid was substituted by other residues that change charge and size, such as arginine, serine, lysine, glutamic acid, and cysteine. Our results indicate that NqrB-Asp-397 forms part of one of the at least two sodium-binding sites and that both size and charge at this position are critical for the function of the enzyme. Moreover, we demonstrate that this residue is involved in cation selectivity, has a critical role in the communication between sodium-binding sites, by promoting cooperativity, and controls the electron transfer step involved in sodium uptake (2Fe-2S → FMNC).

Keep IT Real : On Tools, Emotion, Cognition and Intentionality in Design

NARCIS (Netherlands)

Wendrich, R. E.; Kruiper, R.; Marjanović, D.; M., Štorga; Pavković, N.; Bojčetić, N.; Škec, S.

2016-01-01

Keep IT real, create, build, and develop design tools that support designers during the early phases of design processing. This paper investigates how, and whether, current technology can afford real-time interaction and affective computing in a HDT(E) design tool that integrates and blends

Biology, Culture, and the Origins of Pet-Keeping

OpenAIRE

Harold A. Herzog

2014-01-01

Attachments between non-human animals of different species are surprisingly common in situations involving human agency (e.g., homes, zoos, and wildlife parks). However, cross-species animal friendships analogous to pet-keeping by humans are at least rare and possibly non-existent in nature. Why has pet-keeping evolved only in Homo sapiens? I review theories that explain pet-keeping either as an adaptation or an evolutionary by-product. I suggest that these explanations cannot account for the...

40 CFR 86.1925 - What records must I keep?

Science.gov (United States)

2010-07-01

... it is important to keep required information readily available. (b) Keep the following paper or electronic records of your in-use testing for five years after you complete all the testing required for an... determine why a vehicle failed the vehicle-pass criteria described in § 86.1912. (3) Keep a copy of the...

Redox Specificity of 2-Hydroxyacid-Coupled NAD+/NADH Dehydrogenases: A Study Exploiting “Reactive” Arginine as a Reporter of Protein Electrostatics

Science.gov (United States)

Durani, Susheel

2013-01-01

With “reactive” arginine as a kinetic reporter, 2-hydroxyacid dehydrogenases are assessed in basis of their specialization as NAD+-reducing or NADH-oxidizing enzymes. Specifically, M4 and H4 lactate dehydrogenases (LDHs) and cytoplasmic and mitochondrial malate dehydrogenases (MDHs) are compared to assess if their coenzyme specificity may involve electrostatics of cationic or neutral nicotinamide structure as the basis. The enzymes from diverse eukaryote and prokaryote sources thus are assessed in “reactivity” of functionally-critical arginine as a function of salt concentration and pH. Electrostatic calculations were performed on “reactive” arginines and found good correspondence with experiment. The reductive and oxidative LDHs and MDHs are assessed in their count over ionizable residues and in placement details of the residues in their structures as proteins. The variants found to be high or low in ΔpKa of “reactive” arginine are found to be also strong or weak cations that preferentially oxidize NADH (neutral nicotinamide structure) or reduce NAD+ (cationic nicotinamide structure). The ionized groups of protein structure may thus be important to redox specificity of the enzyme on basis of electrostatic preference for the oxidized (cationic nicotinamide) or reduced (neutral nicotinamide) coenzyme. Detailed comparisons of isozymes establish that the residues contributing in their redox specificity are scrambled in structure of the reductive enzyme. PMID:24391777

[The evolution of nursing record-keeping].

Science.gov (United States)

Didry, Pascale

2017-05-01

Nursing record-keeping forms an integral part of the provision of care. It helps to assure its traceability and monitoring. It also contributes to the circulation of information among the different players involved in the patient's treatment, thereby helping to assure the quality and safety of care. For nurses, whose professional history has its roots in a culture of oral communication, record-keeping represents the affirmation of a real nursing way of thinking. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The plasma membrane-associated NADH oxidase (ECTO-NOX) of mouse skin responds to blue light

Science.gov (United States)

Morre, D. James; Morre, Dorothy M.

2003-01-01

NADH oxidases of the external plasma membrane surface (ECTO-NOX proteins) are characterized by oscillations in activity with a regular period length of 24 min. Explants of mouse skin exhibit the oscillatory activity as estimated from the decrease in A(340) suggesting that individual ECTO-NOX molecules must somehow be induced to function synchronously. Transfer of explants of mouse skin from darkness to blue light (495 nm, 2 min, 50 micromol m(-1) s(-1)) resulted in initiation of a new activity maximum (entrainment) with a midpoint 36 min after light exposure followed by maxima every 24 min thereafter. Addition of melatonin resulted in a new maximum 24 min after melatonin addition. The findings suggest that the ECTO-NOX proteins play a central role in the entrainment of the biological clock both by light and by melatonin.

Implementation of standards at a research institute. Storage and keeping of radioactive materials following DIN 25422

International Nuclear Information System (INIS)

Koeble, T.; Weinand, U.

2016-01-01

The secure storage and keeping of radioactive materials is increasingly important especially in times of a growing threat by terrorists. Authorities and users are jointly recommended to adapt the storage and keeping of radioactive materials to increasing security requirements. Here the different possibilities to fulfil the requirements regarding fire prevention and theft prevention which in Germany are set by DIN 25422 were determined for the radioactive materials and their storage and keeping places present in a research institute. The required measures were than agreed about with the relevant authority. Difficulties which are occurring due to the demanding combination of requirements out of the areas of radiation protection, fire prevention, and theft prevention are discussed. The storage and keeping of radioactive materials especially such of high activity requires a high level of security which must be continuously adapted to rising requirements.

Plasma membrane NADH oxidase of maize roots responds to gravity and imposed centrifugal forces

Science.gov (United States)

Bacon, E.; Morre, D. J.

2001-01-01

NADH oxidase activities measured with excised roots of dark-grown maize (Zea mays) seedlings and with isolated plasma membrane vesicles from roots of dark-grown maize oscillated with a regular period length of 24 min and were inhibited by the synthetic auxin 2,4-dichlorophenoxyacetic [correction of dichorophenoxyacetic] acid. The activities also responded to orientation with respect to gravity and to imposed centrifugal forces. Turning the roots upside down resulted in stimulation of the activity with a lag of about 10 min. Returning the sections to the normal upright position resulted in a return to initial rates. The activity was stimulated reversibly to a maximum of about 2-fold with isolated plasma membrane vesicles, when subjected to centrifugal forces of 25 to 250 x g for 1 to 4 min duration. These findings are the first report of a gravity-responsive enzymatic activity of plant roots inhibited by auxin and potentially related to the gravity-induced growth response. c2001 Editions scientifiques et medicales Elsevier SAS.

Menadione enhances oxyradical formation in earthworm extracts: vulnerability of earthworms to quinone toxicity

International Nuclear Information System (INIS)

Osman, A.M.; Besten, P.J. den; Noort, P.C.M. van

2003-01-01

NAD(P)H-cytochrome c reductase activities have been determined in the earthworms, L. rubellus and A. chlorotica, extracts. Menadione (0.35 mM, maximum concentration tested) was found to stimulate the rates of NADPH- and NADH-dependent cytochrome c reduction by three- and twofold, respectively. Superoxide dismutase (SOD) inhibited completely this menadione-mediated stimulation, suggesting that ·O 2 - is involved in the redox cycling of menadione. However, SOD had no effect on the basal activity (activity in the absence of quinone) in the case of NADH-dependent cytochrome c reduction, whereas it partially inhibited the basal activity of NADPH-cytochrome c reduction. This indicates direct electron transfer in the former case and the formation of superoxide anion in the latter. DT-diaphorase, measured as the dicumarol-inhibitable part of menadione reductase activity, was not detectable in the earthworms' extracts. In contrast, it was found that DT-diaphorase represents about 70% of the menadione reductase activities in the freshwater mussel, Dreissena polymorpha. The results of this work suggest that earthworms, compared with mussels, could be more vulnerable to oxidative stress from quinones due to lack, or very low level of DT-diaphorase, an enzyme considered to play a significant role in the detoxification of quinones. On the contrary, mussels have efficient DT-diaphorase, which catalyzes two-electron reduction of menadione directly to hydroquinone, thus circumventing the formation of semiquinone

Keeping Plateaued Performers Motivated.

Science.gov (United States)

DeLon, Barbara A.

1993-01-01

Discusses the problem of keeping library staff motivated when promotions are not available. Topics addressed include the importance of management training that emphasizes communication skills; alternative ways to help employees grow, including staff development programs, lateral transfers, job rotation, and short-term projects; and helpful…

Microbiological quality of air in free-range and box-stall stable horse keeping systems.

Science.gov (United States)

Wolny-Koładka, Katarzyna

2018-04-07

The aim of this study was to assess the microbiological quality of air in three horse riding centers differing in the horse keeping systems. The air samples were collected in one facility with free-range horse keeping system and two with box stalls of different sizes. The samples were collected over a period of 3 years (2015-2017), four times per year (spring, summer, autumn, winter) to assess the effect of seasonal changes. The prevalence of aerobic mesophilic bacteria, mold fungi, actinomycetes, Staphylococcus spp., and Escherichia coli was determined by the air collision method on Petri dishes with appropriate microbiological media. At the same time, air temperature, relative humidity, and particulate matter concentration (PM 10 , PM 2.5 ) were measured. It was found that the horse keeping system affects the occurrence of the examined airborne microorganisms. Over the 3-year period of study, higher temperature and humidity, as well as particulate matter concentration-which notoriously exceeded limit values-were observed in the facilities with the box-stall system. The air sampled from the largest horse riding center, with the largest number of horses and the box-stall system of horse keeping, was also characterized by the heaviest microbiological contamination. Among others, bacteria from the following genera: Staphylococcus spp., Streptococcus spp., Bacillus spp., and E. coli and fungi from the genera Aspergillus, Fusarium, Mucor, Rhizopus, Penicillium, Trichothecium, Cladosporium, and Alternaria were identified in the analyzed samples.

NADH Oxidase of Streptococcus thermophilus 1131 is Required for the Effective Yogurt Fermentation with Lactobacillus delbrueckii subsp. bulgaricus 2038.

Science.gov (United States)

Sasaki, Yasuko; Horiuchi, Hiroshi; Kawashima, Hiroko; Mukai, Takao; Yamamoto, Yuji

2014-01-01

We previously reported that dissolved oxygen (DO) suppresses yogurt fermentation with an industrial starter culture composed of Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) 2038 and Streptococcus thermophilus 1131, and also found that reducing the DO in the medium prior to fermentation (deoxygenated fermentation) shortens the fermentation time. In this study, we found that deoxygenated fermentation primarily increased the cell number of S. thermophilus 1131 rather than that of L. bulgaricus 2038, resulting in earlier l-lactate and formate accumulation. Measurement of the DO concentration and hydrogen peroxide generation in the milk medium suggested that DO is mainly removed by S. thermophilus 1131. The results using an H2O-forming NADH oxidase (Nox)-defective mutant of S. thermophilus 1131 revealed that Nox is the major oxygen-consuming enzyme of the bacterium. Yogurt fermentation with the S. thermophilus Δnox mutant and L. bulgaricus 2038 was significantly slower than with S. thermophilus 1131 and L. bulgaricus 2038, and the DO concentrations of the mixed culture did not decrease to less than 2 mg/kg within 3 hr. These observations suggest that Nox of S. thermophilus 1131 contributes greatly to yogurt fermentation, presumably by removing the DO in milk.

Neuro-oncology family caregivers' view on keeping track of care issues using eHealth systems: it's a question of time.

Science.gov (United States)

Boele, Florien W; van Uden-Kraan, Cornelia F; Hilverda, Karen; Weimer, Jason; Donovan, Heidi S; Drappatz, Jan; Lieberman, Frank S; Verdonck-de Leeuw, Irma; Sherwood, Paula R

2017-08-01

Primary brain tumors (PBTs) are rare but have a great impact on both patient and family caregiver wellbeing. Supporting caregivers can help them to continue their caregiving activities to maintain the patients' best possible level of quality of life. Efforts to improve PBT caregiver wellbeing should take into account country- or culture-specific differences in care issues and supportive care needs to serve larger caregiver groups. We aimed to explore PBT caregivers' satisfaction with the current supportive care provision, as well as their thoughts on monitoring their care issues with both paper-based and digital instruments. Twelve PBT caregivers were interviewed in the United States. The semi-structured interviews were transcribed verbatim and analyzed by two coders independently. Data were combined with those collected in the Netherlands, following similar methodology (N = 15). We found that PBT caregivers utilize both formal and informal support services, but that those who experience more care issues would prefer more support, particularly in the early disease phase. Keeping track of care issues was thought to provide more insight into unmet needs and help them find professional help, but it requires investment of time and takes discipline. Caregivers preferred a brief and easy-to-use 'blended care' instrument that combines digital monitoring with personal feedback. The present study shows that the preferences of family caregivers in neuro-oncology toward keeping track of care issues are likely not heavily influenced by country- or culture-specific differences. The development of any instrument thus has the potential to benefit a large group of family caregivers.

A Double-Blind, Randomized Clinical Trial of Niacinamide 4% versus Hydroquinone 4% in the Treatment of Melasma

Directory of Open Access Journals (Sweden)

Josefina Navarrete-Solís

2011-01-01

Full Text Available Background. Multiple modalities have been used in the treatment of melasma with variable success. Niacinamide has anti-inflammatory properties and is able to decrease the transfer of melanosomes. Objective. To evaluate the therapeutic effect of topical niacinamide versus hydroquinone (HQ in melasma patients. Patients and Methods. Twenty-seven melasma patients were randomized to receive for eight weeks 4% niacinamide cream on one side of the face, and 4% HQ cream on the other. Sunscreen was applied along the observation period. They were assessed by noninvasive techniques for the evaluation of skin color, as well as subjective scales and histological sections initially and after the treatment with niacinamide. Results. All patients showed pigment improvement with both treatments. Colorimetric measures did not show statistical differences between both sides. However, good to excellent improvement was observed with niacinamide in 44% of patients, compared to 55% with HQ. Niacinamide reduced importantly the mast cell infiltrate and showed improvement of solar elastosis in melasma skin. Side effects were present in 18% with niacinamide versus 29% with HQ. Conclusion. Niacinamide induces a decrease in pigmentation, inflammatory infiltrate, and solar elastosis. Niacinamide is a safe and effective therapeutic agent for this condition.

Poly(neutral red) as a NAD{sup +} reduction catalyst and a NADH oxidation catalyst: Towards the development of a rechargeable biobattery

Energy Technology Data Exchange (ETDEWEB)

Arechederra, Marguerite N.; Addo, Paul K. [Department of Chemistry, Saint Louis University, 3501 Laclede Ave., St. Louis, MO 63103 (United States); Minteer, Shelley D., E-mail: minteers@slu.ed [Department of Chemistry, Saint Louis University, 3501 Laclede Ave., St. Louis, MO 63103 (United States)

2011-01-01

In this paper, we have established that poly(neutral red), PNR, functions as an electrocatalyst for the reduction and oxidation of NAD{sup +}/NADH in a rechargeable biobattery environment. The reversibility of this catalyst was possible only with the addition of Zn{sup 2+} for complexation to the redox polymer. The zinc ion complexation with the polymer facilitates electron and proton transfer to/from the substrate and the NAD{sup +}/NADH coenzyme without forming covalent bonds between the nicotinamide and the substrate surface. This research presents use of this reversible catalyst in a rechargeable biobattery. The rechargeable battery includes a Prussian blue cathode and a bioanode including NAD{sup +}-dependent alcohol dehydrogenase and zinc complexed PNR. This bioanode was coupled to the cathode with Nafion 212 acting as the ion exchange membrane separator between the two compartments. The biobattery has an open circuit potential of 0.545({+-}0.009) V when first assembled and 0.053({+-}0.005) V when fully discharged. However, when fully charged, the biobattery has an open circuit potential of 1.263({+-}0.051) V, a maximum power density of 16.3({+-}4.03) {mu}W cm{sup -3} and a maximum current density of 221({+-}13.2) {mu}A cm{sup -3}. The efficiency and stability of the biobattery were studied by cycling continuously at a discharging rate of 1 C and the results obtained showed reasonable stability over 50 cycles.

49 CFR 172.317 - KEEP AWAY FROM HEAT handling mark.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false KEEP AWAY FROM HEAT handling mark. 172.317 Section... REQUIREMENTS, AND SECURITY PLANS Marking § 172.317 KEEP AWAY FROM HEAT handling mark. (a) General. For... of Division 5.2 must be marked with the KEEP AWAY FROM HEAT handling mark specified in this section...

Effects of NADH-preferring xylose reductase expression on ethanol production from xylose in xylose-metabolizing recombinant Saccharomyces cerevisiae.

Science.gov (United States)

Lee, Sung-Haeng; Kodaki, Tsutomu; Park, Yong-Cheol; Seo, Jin-Ho

2012-04-30

Efficient conversion of xylose to ethanol is an essential factor for commercialization of lignocellulosic ethanol. To minimize production of xylitol, a major by-product in xylose metabolism and concomitantly improve ethanol production, Saccharomyces cerevisiae D452-2 was engineered to overexpress NADH-preferable xylose reductase mutant (XR(MUT)) and NAD⁺-dependent xylitol dehydrogenase (XDH) from Pichia stipitis and endogenous xylulokinase (XK). In vitro enzyme assay confirmed the functional expression of XR(MUT), XDH and XK in recombinant S. cerevisiae strains. The change of wild type XR to XR(MUT) along with XK overexpression led to reduction of xylitol accumulation in microaerobic culture. More modulation of the xylose metabolism including overexpression of XR(MUT) and transaldolase, and disruption of the chromosomal ALD6 gene encoding aldehyde dehydrogenase (SX6(MUT)) improved the performance of ethanol production from xylose remarkably. Finally, oxygen-limited fermentation of S. cerevisiae SX6(MUT) resulted in 0.64 g l⁻¹ h⁻¹ xylose consumption rate, 0.25 g l⁻¹ h⁻¹ ethanol productivity and 39% ethanol yield based on the xylose consumed, which were 1.8, 4.2 and 2.2 times higher than the corresponding values of recombinant S. cerevisiae expressing XR(MUT), XDH and XK only. Copyright © 2011 Elsevier B.V. All rights reserved.

Galileo Station Keeping Strategy

Science.gov (United States)

Perez-Cambriles, Antonio; Bejar-Romero, Juan Antonio; Aguilar-Taboada, Daniel; Perez-Lopez, Fernando; Navarro, Daniel

2007-01-01

This paper presents analyses done for the design and implementation of the Maneuver Planning software of the Galileo Flight Dynamics Facility. The station keeping requirements of the constellation have been analyzed in order to identify the key parameters to be taken into account in the design and implementation of the software.

Keeping Track of Technology

Science.gov (United States)

Dyrli, Kurt O.

2009-01-01

A lack of consistent and accurate auditing and record keeping of district IT equipment can lead to confusion between administrative departments, including redundant purchases, transferred equipment being mislabeled as stolen, computers and other equipment simply being lost, or a variety of other scenarios. This had led to an increased demand for…

Simultaneous determination of levodopa, carbidopa and tryptophan using nanostructured electrochemical sensor based on novel hydroquinone and carbon nanotubes: Application to the analysis of some real samples

International Nuclear Information System (INIS)

Mazloum-Ardakani, Mohammad; Ganjipour, Bahram; Beitollahi, Hadi; Amini, Mohammad Kazem; Mirkhalaf, Fakhradin; Naeimi, Hossein; Nejati-Barzoki, Maryam

2011-01-01

Highlights: → A novel hydroquinone-carbon nanotube paste electrode have been fabricated. → This electrode reduced the oxidation potential of levodopa by about 460 mV. → Some kinetic parameters for oxidation of levodopa has been determined. → This electrode resolved the voltammetric waves of levodopa, carbidopa and tryptophan. → This electrode used for determination of levodopa in some real samples. - Abstract: In the present paper, the use of a novel carbon paste electrode modified by 2, 2'-[1,2-ethanediylbis (nitriloethylidyne)]-bis-hydroquinone (EBNBH) and carbon nanotubes prepared by a simple and rapid method for the determination of levodopa (LD), carbidopa (CD) and tryptophan (Trp) was described. In the first part of the work, cyclic voltammetry was used to investigate the redox properties of this modified electrode at various scan rates. The apparent charge-transfer rate constant, k s , and transfer coefficient, α, for electron transfer between EBNBH and carbon nanotube paste electrode were calculated. In the second part of the work, the mediated oxidation of LD at the modified electrode was described. It has been found that under optimum condition (pH 7.0) in cyclic voltammetry, the oxidation of LD occurs at a potential about 460 mV less positive than that of an unmodified carbon paste electrode. The values of electron transfer coefficient (α), catalytic rate constant (k h ') and diffusion coefficient (D) were calculated for LD, using electrochemical approaches. Differential pulse voltammetry (DPV) exhibited two linear dynamic ranges and a detection limit (3σ) of 0.094 μM for LD. In the third part of the work, simultaneous determination of LD, CD and Trp at the modified electrode was described. Finally, this method was used for the determination of LD in some real samples, using standard addition method.

A Class I UV-Blocking (senofilcon A) Soft Contact Lens Prevents UVA-induced Yellow Fluorescence and NADH loss in the Rabbit Lens Nucleus in vivo

Science.gov (United States)

Giblin, Frank J.; Lin, Li-Ren; Simpanya, Mukoma F.; Leverenz, Victor R.; Fick, Catherine E.

2012-01-01

It is known that fluorescence, much of it caused by UVA light excitation, increases in the aging human lens, resulting in loss of sharp vision. This study used an in vivo animal model to investigate UVA-excited fluorescence in the rabbit lens, which contains a high level of the UVA chromophore NADH, existing both free and bound to λ-crystallin. Also, the ability of a Class I (senofilcon A) soft contact lens to protect against UVA-induced effects on the rabbit lens was tested. Rabbit eyes were irradiated with UVA light in vivo (100 mW/cm2 on the cornea) for 1 hour using monochromatic 365 nm light. Irradiation was conducted in the presence of either a senofilcon A contact lens, a minimally UV-absorbing lotrafilcon A contact lens, or no contact lens at all. Eyes irradiated without a contact lens showed blue 365 nm-excited fluorescence initially, but this changed to intense yellow fluorescence after 1 hour. Isolated, previously irradiated lenses exhibited yellow fluorescence originating from the lens nucleus when viewed under 365 nm light, but showed normal blue fluorescence arising from the cortex. Previously irradiated lenses also exhibited a faint yellow color when observed under visible light. The senofilcon A contact lens protected completely against the UVA-induced effects on fluorescence and lens yellowing, whereas the lotrafilcon A lens showed no protection. The UVA-exposure also produced a 53% loss of total NADH (free plus bound) in the lens nucleus, with only a 13% drop in the anterior cortex. NADH loss in the nucleus was completely prevented with use of a senofilcon A contact lens, but no significant protection was observed with a lotrafilcon A lens. Overall, the senofilcon A lens provided an average of 67% protection against UVA-induced loss of four pyridine nucleotides in four different regions of the lens. HPLC analysis with fluorescence detection indicated a nearly six-fold increase in 365 nm-excited yellow fluorescence arising from lens nuclear �

Adolescent Physical Activity and Motivational Profiles While Keeping a Physical Activity Record

Science.gov (United States)

Fullmer, Matthew O.; Wilkinson, Carol; Prusak, Keven A.; Eggett, Dennis; Pennington, Todd

2018-01-01

Purpose: This study examined the relationship between adolescents (N = 124) from physical education classes keeping a daily online leisure-time physical activity (LTPA) record and feelings of competence toward LTPA, motivational profiles toward LTPA, and LTPA behaviors. Method: A repeated measures ANCOVA was used to examine the relationships…

Increased Furfural Tolerance Due to Overexpression of NADH-Dependent Oxidoreductase FucO in Escherichia coli Strains Engineered for the Production of Ethanol and Lactate▿

OpenAIRE

Wang, X.; Miller, E. N.; Yomano, L. P.; Zhang, X.; Shanmugam, K. T.; Ingram, L. O.

2011-01-01

Furfural is an important fermentation inhibitor in hemicellulose sugar syrups derived from woody biomass. The metabolism of furfural by NADPH-dependent oxidoreductases, such as YqhD (low Km for NADPH), is proposed to inhibit the growth and fermentation of xylose in Escherichia coli by competing with biosynthesis for NADPH. The discovery that the NADH-dependent propanediol oxidoreductase (FucO) can reduce furfural provided a new approach to improve furfural tolerance. Strains that produced eth...

Pet-keeping in early childhood and airway, nose and skin symptoms later in life

DEFF Research Database (Denmark)

Bornehag, C.; Sundell, Jan; Hagerhed, L.

2003-01-01

got rid of pets because of allergy in the family, and 27.3% reported 'avoidance' behaviour towards pets. In a cross-sectional analysis current pet-keeping was 'protective', but this may be due to the fact that people avoid exposing their child to something that they believe is a risk factor......Background: It is discussed whether exposure to pets during childhood is a risk or a protective factor for sensitization and allergic symptoms. The aim of this study was to investigate the association between pet-keeping at time of birth and allergic symptoms in airways, nose and skin among young...... children in Sweden. Methods: A questionnaire was sent to the parents of 14 077 children (1-6 years), the focus being on allergic symptoms, home environment and other background factors including pet-keeping and avoidance behaviour. The response rate was 79%. Results: Almost one-tenth of the population had...

Microchip-electrochemistry route for rapid screening of hydroquinone and arbutin from miscellaneous samples: Investigation of the robustness of a simple cross-injector system

International Nuclear Information System (INIS)

Crevillen, Agustin G.; Barrigas, Ines; Blasco, Antonio Javier; Gonzalez, Maria Cristina; Escarpa, Alberto

2006-01-01

This work examines in deep the analytical performance of an example of 'first-generation' microdevices: capillary electrophoresis microchip (CE) with end-channel electrochemical detection (ED). A hydroquinone and arbutin separation strategically chosen as route involving pharmaceutical-clinical testing, public safety and food control scenes was carried out. The reproducibility of the unpinched electrokinetic protocol was carefully studied and the technical possibility of working indiscriminately and/or sequentially with both simple cross-injectors was also demonstrated using a real sample (R.S.D.'s less than 7%). The robustness of the injection protocol allowed checking the state of the microchip/detector coupling and following the extraction efficiency of the analyte from real sample. Separation variables such as pH, ionic strength and, separation voltage were also carefully assayed and optimized. Analyte screening was performed using borate buffer (pH 9, 60 mM) in less than 180 s in the samples studied improving dramatically the analysis times used for the same analytes on a conventional scale (15 min), with good precision (R.S.D.'s ranging 5-10%), accuracy (recoveries ranging 90-110%) and acceptable resolution (Rs ≥ 1.0). In addition, the excellent analytical performance of the overall analytical method indicated the quality of the whole analytical microsystem and allowed to introduce the definition of robustness for methodologies developed into the 'lab-on-a-chip' scene

Microchip-electrochemistry route for rapid screening of hydroquinone and arbutin from miscellaneous samples: Investigation of the robustness of a simple cross-injector system

Energy Technology Data Exchange (ETDEWEB)

Crevillen, Agustin G. [Dpto. Quimica Analitica e Ingenieria Quimica, Universidad de Alcala, 28871 Alcala de Henares, Madrid (Spain); Barrigas, Ines [Dpto. Quimica Analitica e Ingenieria Quimica, Universidad de Alcala, 28871 Alcala de Henares, Madrid (Spain); Blasco, Antonio Javier [Dpto. Quimica Analitica e Ingenieria Quimica, Universidad de Alcala, 28871 Alcala de Henares, Madrid (Spain); Gonzalez, Maria Cristina [Dpto. Quimica Analitica e Ingenieria Quimica, Universidad de Alcala, 28871 Alcala de Henares, Madrid (Spain); Escarpa, Alberto [Dpto. Quimica Analitica e Ingenieria Quimica, Universidad de Alcala, 28871 Alcala de Henares, Madrid (Spain)]. E-mail: alberto.escarpa@uah.es

2006-03-15

This work examines in deep the analytical performance of an example of 'first-generation' microdevices: capillary electrophoresis microchip (CE) with end-channel electrochemical detection (ED). A hydroquinone and arbutin separation strategically chosen as route involving pharmaceutical-clinical testing, public safety and food control scenes was carried out. The reproducibility of the unpinched electrokinetic protocol was carefully studied and the technical possibility of working indiscriminately and/or sequentially with both simple cross-injectors was also demonstrated using a real sample (R.S.D.'s less than 7%). The robustness of the injection protocol allowed checking the state of the microchip/detector coupling and following the extraction efficiency of the analyte from real sample. Separation variables such as pH, ionic strength and, separation voltage were also carefully assayed and optimized. Analyte screening was performed using borate buffer (pH 9, 60 mM) in less than 180 s in the samples studied improving dramatically the analysis times used for the same analytes on a conventional scale (15 min), with good precision (R.S.D.'s ranging 5-10%), accuracy (recoveries ranging 90-110%) and acceptable resolution (Rs {>=} 1.0). In addition, the excellent analytical performance of the overall analytical method indicated the quality of the whole analytical microsystem and allowed to introduce the definition of robustness for methodologies developed into the 'lab-on-a-chip' scene.

Improving the quality of endodontic record keeping through clinical audit.

Science.gov (United States)

King, E; Shekaran, L; Muthukrishnan, A

2017-03-10

Introduction Record keeping is an essential part of day-to-day practice and plays an important role in treatment, audit and dento-legal procedures. Creating effective endodontic records is challenging due to the scope of information required for comprehensive notes. Two audits were performed to assess the standards of endodontic record keeping by dentists in a restorative dentistry department and students on an endodontic MSc course.Methods Fifty sets of departmental records and 10 sets of student records were retrospectively evaluated against the European Society of Endodontology 2006 guidelines. Results of the first cycle of both audits were presented to departmental staff and MSc students, alongside an educational session. Additionally, departmental guidelines, consent leaflets and endodontic record keeping forms were developed. Both audits were repeated using the same number of records, thus completing both audit cycles.Results The most commonly absent records included consent, anaesthetic details, rubber dam method, working length reference point, irrigation details and obturation technique. Almost all areas of record keeping improved following the second audit cycle, with some areas reaching 100% compliance when record keeping forms were used. Statistically significant improvements were seen in 24 of the 29 areas in the departmental audit and 14 of the 29 areas in the MSc audit (P = 0.05).Conclusions Significant improvements in endodontic record keeping can be achieved through the provision of education, departmental guidelines, consent leaflets and endodontic record keeping forms.

Application of the Fenton's process in a bubble column reactor for hydroquinone degradation.

Science.gov (United States)

Lima, Vanessa N; Rodrigues, Carmen S D; Madeira, Luis M

2017-11-27

The aim of this study was to assess the degradation and mineralization of hydroquinone (HQ) by the Fenton's process in a bubble column reactor (BCR). The effect of the main operating variables, namely, air flow rate, effluent volume, hydrogen peroxide (H 2 O 2 ) concentration, catalyst (Fe 2+ ) dose, initial pH, and temperature, were assessed. For all air flow rates tested, no concentration gradients along the column were noticed, evidencing that a good mixing was reached in the BCR. For the best conditions tested ([H 2 O 2 ] = 500 mg/L, [Fe 2+ ] = 45 mg/L, T = 24 °C, Q air  = 2.5 mL/min, pH = 3.0, and V = 5 L), complete HQ degradation was reached, with ~ 39% of total organic carbon (TOC) removal, and an efficiency of the oxidant use-η H2O2 -of 0.39 (ratio between TOC removed per H 2 O 2 consumed normalized by the theoretical stoichiometric value); moreover, a non-toxic effluent was generated. Under these conditions, the intermediates and final oxidation compounds identified and quantified were a few carboxylic acids, namely, maleic, pyruvic, and oxalic. As a strategy to improve the TOC removal, a gradual dosage of the optimal H 2 O 2 concentration was implemented, being obtained ~ 55% of mineralization (with complete HQ degradation). Finally, the matrix effect was evaluated, for which a real wastewater was spiked with 100 mg/L of HQ; no reduction in terms of HQ degradation and mineralization was observed compared to the solution in distilled water.

In vitro effects of myricetin, morin, apigenin, (+)-taxifolin, (+)-catechin, (−)-epicatechin, naringenin and naringin on cytochrome b5 reduction by purified NADH-cytochrome b5 reductase

International Nuclear Information System (INIS)

Çelik, Haydar; Koşar, Müberra; Arinç, Emel

2013-01-01

Highlights: • We assessed inhibitory effects of 8 dietary flavonoids on cytochrome b5 reduction by purified NADH-cytochrome b5 reductase. • The flavonol myricetin was the most potent in inhibiting cytochrome b5 reduction with an IC 50 value of 0.35 μM. • We investigated kinetics of myricetin-induced inhibition in detail. • We explored the structure–inhibitory activity relationship of compounds. • Modulation of cytochrome b5 reduction indicates a potential for myricetin to lead to some food–drug/xenobiotic interactions. - Abstract: The microsomal NADH-dependent electron transport system consisting of cytochrome b5 reductase and cytochrome b5 participates in a number of physiologically important processes including lipid metabolism as well as is involved in the metabolism of various drug and xenobiotics. In the present study, we assessed the inhibitory effects of eight dietary flavonoids representing five distinct chemical classes on cytochrome b5 reduction by purified cytochrome b5 reductase. From the flavonoids tested, myricetin was the most potent in inhibiting cytochrome b5 reduction with an IC 50 value of 0.35 μM. Myricetin inhibited b5 reductase noncompetitively with a K i of 0.21 μM with respect to cofactor NADH, and exhibited a non-linear relationship indicating non-Michaelis–Menten kinetic binding with respect to cytochrome b5. In contrast to the potent inhibitory activity of myricetin, (+)-taxifolin was found to be a weak inhibitor (IC 50 = 9.8 μM). The remaining flavonoids were inactive within the concentration range tested (1–50 μM). Analysis of structure–activity data suggested that simultaneous presence of three OH groups in ring B is a primary structural determinant for a potent enzyme inhibition. Our results suggest that inhibition of the activity of this system by myricetin or myricetin containing diets may influence the metabolism of therapeutic drugs as well as detoxification of xenobiotics

Cloning, molecular characterization and expression of a cDNA encoding a functional NADH-cytochrome b5 reductase from Mucor racemosus PTCC 5305 in E. coli

Directory of Open Access Journals (Sweden)

NED A SETAYESH

2009-01-01

Full Text Available The present work aims to study a new NADH-cytochrome b5 reductase (cb5r from Mucor racemosus PTCC 5305. A cDNA coding for cb s r was isolated from a Mucor racemosus PTCC 5305 cDNA library. The nucleotide sequence of the cDNA including coding and sequences flanking regions was determined. The open reading frame starting from ATG and ending with TAG stop codon encoded 228 amino acids and displayed the closest similarity (73% with Mortierella alpina cb s r. Lack of hydrophobic residues in the N-terminal sequence was apparent, suggesting that the enzyme is a soluble isoform. The coding sequence was then cloned in the pET16b transcription vector carrying an N-terminal-linked His-Tag® sequence and expressed in Escherichia coli BL21 (DE3. The enzyme was then homogeneously purified by a metal affinity column. The recombinant Mucor enzyme was shown to have its optimal activity at pH and temperature of about 7.5 and 40 °C, respectively. The apparent Km value was calculated to be 13 μM for ferricyanide. To our knowledge, this is the first report on cloning and expression of a native fungal soluble isoform of NADH-cytochrome b5 reductase in E. coli.

Good government and good governance: record keeping in a ...

African Journals Online (AJOL)

This article addresses the challenges that arise when record keeping systems are advocated as a necessary under-pinning for good government and good governance. The relationship between record keeping and accountability is analysed and contextualised in relation to transparency and Freedom of Information ...

78 FR 23824 - Reports, Forms, and Record Keeping Requirements

Science.gov (United States)

2013-04-22

... questions, potential participant questions, logistical questions, and conclusion. The total estimated annual burden will be 40 hours. Participants will incur no costs from the data collection and participants will incur no record keeping burden and no record keeping cost from the information collection. Authority: 44...

4-H Animal Science: Financial Record Keeping Book

OpenAIRE

Callan, Peter L.; Thompson, John; Woodard, Scott; Kastan, Christine

2017-01-01

This document includes six lessons that focus on financial record keeping in relation to raising and caring for livestock. These lessons include activities and objectives ranging from selection of an animal for the project to keeping records of costs of feed, and other expenses. There are lessons which also analysis of data to determine if goals were met, and if the project was profitable.

Fractional erbium-doped yttrium aluminum garnet laser-assisted drug delivery of hydroquinone in the treatment of melasma

Science.gov (United States)

Badawi, Ashraf M; Osman, Mai Abdelraouf

2018-01-01

Background Melasma is a difficult-to-treat hyperpigmentary disorder. Ablative fractional laser (AFL)-assisted delivery of topically applied drugs to varied targets in the skin has been an area of ongoing study and research. Objective The objective of this study was to evaluate the efficacy and safety of fractional erbium-doped yttrium aluminum garnet (Er:YAG) laser as an assisted drug delivery for enhancing topical hydroquinone (HQ) permeation into the skin of melasma patients. Patients and methods Thirty female patients with bilateral melasma were randomly treated in a split-face controlled manner with a fractional Er:YAG laser followed by 4% HQ cream on one side and 4% HQ cream alone on the other side. All patients received six laser sessions with a 2-week interval. The efficacy of treatments was determined through photographs, dermoscopic photomicrographs and Melasma Area Severity Index (MASI) score, all performed at baseline and at 12 weeks of starting therapy. The patient’s level of satisfaction was also recorded. Results Er:YAG laser + HQ showed significantly better results (plaser + HQ side vs HQ side. Minor reversible side effects were observed on both sides. Conclusion AFL-assisted delivery of HQ is a safe and effective method for the treatment of melasma. PMID:29379308

Simultaneous determination of hydroquinone and catechol based on glassy carbon electrode modified with gold-graphene nanocomposite

International Nuclear Information System (INIS)

Ma, X.; Liu, Z.; Qiu, C.; Chen, T.; Ma, H.

2013-01-01

We have synthesized a virtually monodisperse gold-graphene (Au-G) nanocomposite by a single-step chemical reduction method in aqueous dimethylformamide solution. The nanoparticles are homogenously distributed over graphene nanosheets. A glassy carbon electrode was modified with this nanocomposite and displayed high electrocatalytic activity and extraordinary electronic transport properties due to its large surface area. It enabled the simultaneous determination of hydroquinone (HQ) and catechol (CC) in acetate buffer solution of pH 4.5. Two pairs of well-defined, quasi-reversible redox peaks are obtained, one for HQ and its oxidized form, with a 43 mV separation of peak potentials (ΔEp), the other for CC and its oxidized form, with a ΔEp of 39 mV. Due to the large separation of oxidation peak potentials (102 mV), the concentrations of HQ and CC can be easily determined simultaneously. The oxidation peak currents for both HQ and CC increase linearly with the respective concentrations in the 1.0 μM to 0.1 mM concentration range, with the detection limits of 0.2 and 0. 15 μM (S/N = 3), respectively. The modified electrode was successfully applied to the simultaneous determination of HQ and CC in spiked tap water, demonstrating that the Au-G nanocomposite may act as a high-performance sensing material in the selective detection of some environmental pollutants. (author)

The KEEP Phone Discrimination Test. Technical Report No. 64.

Science.gov (United States)

Smith, Kenneth; And Others

The urban, ethnically Hawaiian child typically experiences great difficulty in learning to read English. In order to determine whether phonological confusion is a source of dialectical interference, the Kamehameha Early Education Program (KEEP) Phone Discrimination Test (KPDT) was developed for the one hundred twelve students in the KEEP school…

78 FR 78504 - Reports, Forms, and Record Keeping Requirements

Science.gov (United States)

2013-12-26

..., logistical questions, and conclusion. The total estimated annual burden will be 15 hours. Participants will incur no costs from the data collection and participants will incur no record keeping burden and no record keeping cost from the information collection. If the Optional Task is funded, we assume a subset...

Occupational Health Record-keeping System (OHRS)

Data.gov (United States)

Department of Veterans Affairs — Occupational Health Record-keeping System (OHRS) is part of the Clinical Information Support System (CISS) portal framework and the initial CISS partner system. OHRS...

KEEP Motivational Research: Strategy and Results. Technical Report #24.

Science.gov (United States)

Gallimore, Ronald; Tharp, Roland G.

This report briefly summarizes the motivation research strategy and results from the Kamehameha Early Education Program (KEEP). The rationale behind KEEP's use of on-task behavior to measure student motivation is discussed and the two strategies of motivation enhancement researched are described. These two strategies were: (1) staff training in…

Lumba-Lumba Hidung Botol Laut Jawa Adalah Tursiops aduncus Berdasar Sekuen Gen NADH Dehidrogenase Subunit 6 (VERIFICATION BOTTLENOSE DOLPHINS FROM JAVA SEA IS TURSIOPS ADUNCUS BASED ON GENE SEQUENCES OF NADH DEHYDROGENASE SUBUNIT 6

Directory of Open Access Journals (Sweden)

Rini Widayanti

2014-05-01

Full Text Available Bottlenose dolphins (Tursiops sp. is one of the aquatic mammals widely spread in the marines ofIndonesia archipelago, especially the Java Sea. The taxonomy of the genus Tursiops is still  controversial.The purpose of this study was to examine the molecular basis of Tursiops sp of Java sea marine origin onthe basis of its NADH dehydrogenase gene subunit 6 (ND6 sequences. Samples of blood were collectedfrom five male bottle nose dolphins from captivity of PT. Wersut Seguni Indonesia. DNA was isolated,amplified by polymerase chain reaction (PCR, sequenced, and analyzed the data using the MEGA v. 5.1program. The results of PCR amplification was 868 base pairs (bp, DNA sequencing showed that 528nucleotides were ND6 gene, nucleotide at the position of 387 could be used to distinguish the bottle nosedolphins Java marine origin with T. aduncus.   Filogram using Neighbor joining method based on thenucleotide sequence of the gene ND6, showed that bottle nose dolphins Java marine origin belong to groupof T. aduncus.

Racing to keep up; Aufholjagd

Energy Technology Data Exchange (ETDEWEB)

Bernreuter, Johannes

2011-10-31

In the summer of 2010, Manz AG presented a turnkey concept for production of thin film modules of copper-indium-gallium diselenide. The producer then had to make amends in view of the dramatic price drop. Thin film modules of micromorphous silicon have problems to keep up.

Why Should Scholars Keep Coming Back to John Dewey?

Science.gov (United States)

Gordon, Mordechai

2016-01-01

This essay attempts to explain why philosophers, philosophers of education, and scholars of democracy should keep coming back to John Dewey for insights and inspiration on issues related to democracy and education. Mordechai Gordon argues that there are four major reasons that contribute to scholars' need to keep returning to Dewey for inspiration…

Menadione enhances oxyradical formation in earthworm extracts: vulnerability of earthworms to quinone toxicity

Energy Technology Data Exchange (ETDEWEB)

Osman, A.M.; Besten, P.J. den; Noort, P.C.M. van

2003-10-08

NAD(P)H-cytochrome c reductase activities have been determined in the earthworms, L. rubellus and A. chlorotica, extracts. Menadione (0.35 mM, maximum concentration tested) was found to stimulate the rates of NADPH- and NADH-dependent cytochrome c reduction by three- and twofold, respectively. Superoxide dismutase (SOD) inhibited completely this menadione-mediated stimulation, suggesting that {center_dot}O{sub 2}{sup -} is involved in the redox cycling of menadione. However, SOD had no effect on the basal activity (activity in the absence of quinone) in the case of NADH-dependent cytochrome c reduction, whereas it partially inhibited the basal activity of NADPH-cytochrome c reduction. This indicates direct electron transfer in the former case and the formation of superoxide anion in the latter. DT-diaphorase, measured as the dicumarol-inhibitable part of menadione reductase activity, was not detectable in the earthworms' extracts. In contrast, it was found that DT-diaphorase represents about 70% of the menadione reductase activities in the freshwater mussel, Dreissena polymorpha. The results of this work suggest that earthworms, compared with mussels, could be more vulnerable to oxidative stress from quinones due to lack, or very low level of DT-diaphorase, an enzyme considered to play a significant role in the detoxification of quinones. On the contrary, mussels have efficient DT-diaphorase, which catalyzes two-electron reduction of menadione directly to hydroquinone, thus circumventing the formation of semiquinone.

One-electron oxidation of the hydroquinonic form of vitamin K by OH· and N3· free radicals. A steady-state gamma radiolysis study

International Nuclear Information System (INIS)

Nguyen Van Binh, E.; Gardes-Albert, M.; Ferradini, C.; Acher, F.; Azerad, R.

1991-01-01

The oxidation of a water-soluble model of vitamin K hydroquinone, symbolised by KH 2 p, has been studied by γ radiolysis using OH· or N 3 · free radicals as oxidants. Irradiation doses were up to 300 Gy. The analysis of final products by spectrophotometric absorption and HPLC allowed to characterize the formation of the quinone K and to estimate the initial yield of KH 2 p-disappearance and K-formation. N 3 · radicals led selectively to the formation of the quinone K with a G-value of (3.0 ± 0.3) x 10 -7 mol/J, thus involving a simple one-electron oxidation mechanism. On the contrary, when OH· radicals oxidized KH 2 p, in addition to the quinone, other non identified species were simultaneously produced during the radiolysis, thus requiring a more complex oxidation mechanism [fr

EFFECT OF GENOTYPE, SEX AND KEEPING TECHNOLOGY ON THE CHEMICAL COMPOUNDS OF BREAST AND THIGH MEAT

Directory of Open Access Journals (Sweden)

SZ. KONRÁD

2009-10-01

Full Text Available In the recent decades because of the alternative poultry meat production technologies (free range and organic farming, which are gaining ground in some of the European countries, only special slow growing breeds and hybrids can be used. The end products created by crossing the indigenous Yellow Hungarian hen with different meat type cocks were suitable for alternative keeping technology. The valuable meat parts of the pure bred Yellow Hungarian kept in free range for 84 days and the end product created with crossing (first group as well as the valuable meat parts of Ross 308 broilers fattened for 42 days in intensive keeping technology (second group were thoroughly examined in order to establish whether the genotype, sex and/or keeping technology has any kind of influence on different chemical parameters of the meat. There were no essential differences between the dry matter content of breast meat of the two different keeping technology groups (25.34 and 26.25%. However, dry matter content of thigh was 5.28 to 7.48 percentage points higher in the second group. Protein contents of breast and thigh meat were not affected by the keeping technology. Fat content of thigh meat was two and a half times higher than in the first group (6.03 and 13.73%. Thus, this study have revealed that only the ash content of breast meat affected from the keeping technology, as this parameter was higher in the first group than the second group (0.84 to 1.05 % vs 0.53 %.

Searching for Orbits with Minimum Fuel Consumption for Station-Keeping Maneuvers: An Application to Lunisolar Perturbations

Directory of Open Access Journals (Sweden)

Antonio Fernando Bertachini de Almeida Prado

2013-01-01

Full Text Available The present paper has the goal of developing a new criterion to search for orbits that minimize the fuel consumption for station-keeping maneuvers. This approach is based on the integral over the time of the perturbing forces. This integral measures the total variation of velocity caused by the perturbations in the spacecraft, which corresponds to the equivalent variation of velocity that an engine should deliver to the spacecraft to compensate the perturbations and to keep its orbit Keplerian all the time. This integral is a characteristic of the orbit and the set of perturbations considered and does not depend on the type of engine used. In this sense, this integral can be seen as a criterion to select the orbit of the spacecraft. When this value becomes larger, more consumption of fuel is required for the station keeping, and, in this sense, less interesting is the orbit. This concept can be applied to any perturbation. In the present research, as an example, the perturbation caused by a third body is considered. Then, numerical simulations considering the effects of the Sun and the Moon in a satellite around the Earth are shown to exemplify the method.

In vivo (31) P MRS assessment of intracellular NAD metabolites and NAD(+) /NADH redox state in human brain at 4 T.

Science.gov (United States)

Lu, Ming; Zhu, Xiao-Hong; Chen, Wei

2016-07-01

NAD(+) and NADH play key roles in cellular respiration. Intracellular redox state defined by the NAD(+) /NADH ratio (RX) reflects the cellular metabolic and physiopathological status. By taking advantage of high/ultrahigh magnetic field strengths, we have recently established a novel in vivo (31) P MRS-based NAD assay for noninvasive and quantitative measurements of intracellular NAD concentrations and redox state in animal and human brains at 16.4 T, 9.4 T and 7 T. To explore its potential for clinical application, in this study we investigated the feasibility of assessing the NAD metabolism and redox state in human brain at a lower field of 4 T by incorporating the (1) H-decoupling technique with the in vivo (31) P NAD assay. The use of (1) H decoupling significantly narrowed the linewidths of NAD and α-ATP resonances, resulting in higher sensitivity and better spectral resolution as compared with the (1) H-coupled (31) P spectrum. These improvements made it possible to reliably quantify cerebral NAD concentrations and RX, consistent with previously reported results obtained from similar age human subjects at 7 T. In summary, this work demonstrates the capability and utility of the (1) H-decoupled (31) P MRS-based NAD assay at lower field strength; thus, it opens new opportunities for studying intracellular NAD metabolism and redox state in human brain at clinical settings. This conclusion is supported by the simulation results, indicating that similar performance and reliability as observed at 4T can be achieved at 3 T with the same signal-to-noise ratio. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Gate-keeping in the Age of Information Society

DEFF Research Database (Denmark)

Andersen, Kim Normann; Medaglia, Rony; Henriksen, Helle Zinner

’ being reluctant to accept imposed standards and control from central level (top-down) but also avoiding demands from parents (and children) on transparency and accountability (bottom-up). The lack of accessibility of grades on the web can thus be seen as a classical gate-keeping mechanism evolving...... in the age of information society where expectations of end-of-gatekeeping by providing accessibility and transparency using information systems has been outnumbered by classical forces of gate-keeping....

Dementia - keeping safe in the home

Science.gov (United States)

... this page: //medlineplus.gov/ency/patientinstructions/000031.htm Dementia - keeping safe in the home To use the ... make sure the homes of people who have dementia are safe for them. Safety Tips for the ...

A Class I UV-blocking (senofilcon A) soft contact lens prevents UVA-induced yellow fluorescence and NADH loss in the rabbit lens nucleus in vivo.

Science.gov (United States)

Giblin, Frank J; Lin, Li-Ren; Simpanya, Mukoma F; Leverenz, Victor R; Fick, Catherine E

2012-09-01

It is known that fluorescence, much of it caused by UVA light excitation, increases in the aging human lens, resulting in loss of sharp vision. This study used an in vivo animal model to investigate UVA-excited fluorescence in the rabbit lens, which contains a high level of the UVA chromophore NADH, existing both free and bound to λ-crystallin. Also, the ability of a Class I (senofilcon A) soft contact lens to protect against UVA-induced effects on the rabbit lens was tested. Rabbit eyes were irradiated with UVA light in vivo (100 mW/cm(2) on the cornea) for 1 h using monochromatic 365 nm light. Irradiation was conducted in the presence of either a senofilcon A contact lens, a minimally UV-absorbing lotrafilcon A contact lens, or no contact lens at all. Eyes irradiated without a contact lens showed blue 365 nm-excited fluorescence initially, but this changed to intense yellow fluorescence after 1 h. Isolated, previously irradiated lenses exhibited yellow fluorescence originating from the lens nucleus when viewed under 365 nm light, but showed normal blue fluorescence arising from the cortex. Previously irradiated lenses also exhibited a faint yellow color when observed under visible light. The senofilcon A contact lens protected completely against the UVA-induced effects on fluorescence and lens yellowing, whereas the lotrafilcon A lens showed no protection. The UVA-exposure also produced a 53% loss of total NADH (free plus bound) in the lens nucleus, with only a 13% drop in the anterior cortex. NADH loss in the nucleus was completely prevented with use of a senofilcon A contact lens, but no significant protection was observed with a lotrafilcon A lens. Overall, the senofilcon A lens provided an average of 67% protection against UVA-induced loss of four pyridine nucleotides in four different regions of the lens. HPLC analysis with fluorescence detection indicated a nearly six-fold increase in 365 nm-excited yellow fluorescence arising from lens nuclear �

Detection of early metabolic alterations in the ocular fundus of diabetic patients by time-resolved autofluorescence of endogenous fluorophores

Science.gov (United States)

Schweitzer, D.; Klemm, M.; Quick, S.; Deutsch, L.; Jentsch, S.; Hammer, M.; Dawczynski, J.; Kloos, C. H.; Mueller, U. A.

2011-07-01

Measurements of time-resolved autofluorescence (FLIM) at the human ocular fundus of diabetic patients permit the detection of early pathologic alterations before signs of diabetic retinopathy are visible. The measurements were performed by the Jena Fluorescence Lifetime Laser Scanner Ophthalmoscope applying time-correlated single photon counting (TCSPC) in two spectral channels (K1: 490-560 nm, K2:560-700ps). The fluorescence was excited by 70 ps pulses (FWHM) at 448 nm. The decay of fluorescence intensity was triple-exponentially approximated. The frequency of amplitudes, lifetimes, and relative contributions was compared in fields of the same size and position in healthy subjects and in diabetic patients. The most sensitive parameter was the lifetime T2 in the short-wavelength channel, which corresponds to the neuronal retina. The changes in lifetime point to a loss of free NADH and an increased contribution of protein-bound NADH in the pre-stage of diabetic retinopathy.

Mono and bimetallic nanoparticles of gold, silver and palladium-catalyzed NADH oxidation-coupled reduction of Eosin-Y

Science.gov (United States)

Santhanalakshmi, J.; Venkatesan, P.

2011-02-01

Mono metallic (Au, Ag, Pd) and bimetallic (Au-Ag, Ag-Pd, Au-Pd) with 1:1 mol stoichiometry, nanoparticles are synthesized using one-pot, temperature controlled chemical method using cetyltrimethylammonium bromide (CTAB) as the capping agent. The particle sizes (Au = 5.6, Ag = 5.0, Pd = 6.0, Au-Ag = 9.2, Ag-Pd = 9.6, Au-Pd = 9.4 nm) are characterized by UV-Vis, HRTEM, and XRD measurements, respectively. CTAB bindings onto mono and bimetallic nanoparticles are analyzed by FTIR spectra. The catalytic activities of mono and bimetallic nanoparticles are tested on the reaction between NADH oxidation and Eosin-Y reduction. The effects of base, pH, ionic strength, nature of mono and bimetallic catalysts are studied and the reaction conditions are optimized. Bimetallic nanoparticles exhibited better catalysis than the mono metallic nanoparticles, which may be due to the electronic effects of the core to shell metal atoms.

Mental Health: Keeping Your Emotional Health

Science.gov (United States)

... Basics Sports Safety Injury Rehabilitation Emotional Well-Being Mental Health Sex and Birth Control Sex and Sexuality Birth ... PPD) Home Prevention and Wellness Emotional Well-Being Mental Health Mental Health: Keeping Your Emotional Health Mental Health: ...

Assignment of stock keeping units to parallel undirectional picking

Directory of Open Access Journals (Sweden)

Matthews, Jason

2015-05-01

Full Text Available An order picking system consisting of a number of parallel unidirectional picking lines is investigated. Stock keeping units (SKUs that are grouped by product type into distributions (DBNs are assigned daily to available picking lines. A mathematical programming formulation and its relaxations is presented. A greedy insertion and a greedy phased insertion are further introduced to obtain feasible results within usable computation times for all test cases. The walking distance of the pickers was shown to decrease by about 22 per cent compared with the current assignment approach. However, product handling and operational risk increases.

Evaluation of various strategies to formation of pH responsive hydroquinone-terminated films on carbon electrodes

International Nuclear Information System (INIS)

Holm, Allan Hjarbaek; Vase, Karina Hojrup; Winther-Jensen, Bjorn; Pedersen, Steen Uttrup; Daasbjerg, Kim

2007-01-01

The hydroquinone/quinone (H 2 Q/Q) redox system was tethered to glassy carbon surfaces using first an electrochemical pre-oxidation treatment to afford carboxylic acid functionalities followed by immobilizing the H 2 Q precursor, n-(2,5-dimethoxyphenyl)alkan-1-amine (general structure: H 2 N-(CH 2 ) n -C 6 H 3 (OCH 3 ) 2 , n = 1, 2, 4, 8, and 12), by carbodiimide chemistry and a final demethylation reaction. The resultant surfaces exhibited the expected chemical reversibility in aqueous solution with a pH-sensitive position of the formal potential (∼55 mV/pH unit), and an increase in the peak potential separation going from 0.02 V for n = 1 to 0.21 V for n = 12. The films were very robust and could withstand prolonged sonication and relatively large potential excursions. While the films followed the expected kinetic distance dependence for up to 4 methylene units the electrode kinetics was faster than expected for longer alkyl spacers. We suggest that film disorder, electrode-mediating effects, and a roughened electrode material could account for these apparent inconsistencies. To further understand such effects, two complementary electrode modification strategies leading to better film ordering on carbon were adapted; immobilizing a thin layer of benzoic acid by oxidative deposition of 4-aminobenzoic acid or employing a plasma deposition process to tether an acid analogue. Analysis of the various electrodes was accomplished by electrochemical methods, atomic force microscopy, and X-ray photoelectron spectroscopy

Dose record keeping: a multi purpose tool in individual monitoring

International Nuclear Information System (INIS)

Bermann, F.; Julius, H.W.

1993-01-01

Proper recording of radiation doses is an essential part of the process of individual monitoring and shares in the same objective. A dose record keeping system is more than just a computer based data storage system and should rather be a Dose Registration and Information System (DRIS). Objectives of dose record keeping are given. As a result of the integration of member states of the European Communities, co-operation and exchange of personnel between countries will be increasing. This will probably require national dose registration systems and adequate data communication between them. These developments emphasize the necessity for international harmonization of dose record keeping systems and categorization of the data they contain. General characteristics and specific aspects of dose record keeping systems will be dealt with. Attention will also be given to some special applications of the recorded information, such as: the use of data for epidemiological studies and for QA purposes. (authors). 5 tabs., 4 refs

Keeping You Close at a Distance

DEFF Research Database (Denmark)

Torbenfeldt Bengtsson, Tea; Mølholt, Anne-Kirstine

2016-01-01

The integration of ethics into research with young people in vulnerable life situations is an on-going challenge that cannot be solved through predefined guidelines or fixed standards. In this article, we address the ethical predicaments of keeping in contact with young people in vulnerable life ...... the blurriness of what is appropriate could lead to suggestions for more well-defined ethical guidelines, we argue that the best and most ethical way to deal with this ambiguity is to recognize it and actively address it as both a practical and an academic challenge.......The integration of ethics into research with young people in vulnerable life situations is an on-going challenge that cannot be solved through predefined guidelines or fixed standards. In this article, we address the ethical predicaments of keeping in contact with young people in vulnerable life...

FT-IR, FT-Raman spectra, density functional computations of the vibrational spectra and molecular conformational analysis of 2,5-di-tert-butyl-hydroquinone

Science.gov (United States)

Subramanian, N.; Sundaraganesan, N.; Dereli, Ö.; Türkkan, E.

2011-12-01

The purpose of finding conformer among six different possible conformers of 2,5-di-tert-butyl-hydroquinone (DTBHQ), its equilibrium geometry and harmonic wavenumbers were calculated by the B3LYP/6-31G(d,p) method. The infrared and Raman spectra of DTBHQ were recorded in the region 400-4000 cm -1 and 50-3500 cm -1, respectively. In addition, the IR spectra in CCl 4 at various concentrations of DTBHQ are also recorded. The computed vibrational wavenumbers were compared with the IR and Raman experimental data. Computational calculations at B3LYP level with two different basis sets 6-31G(d,p) and 6-311++G(d,p) are also employed in the study of the possible conformer of DTBHQ. The complete assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes, calculated using VEDA 4 program. The general agreement between the observed and calculated frequencies was established.

Design of the control system for fixed-point keeping in FPSO (Floating Production Storage and Offloading); FPSO no teiten hoji no tame no seigyokei no sekkei ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Kijima, K; Murata, W; Furukawa, Y [Kyushu University, Fukuoka (Japan). Faculty of Engineering

1997-10-01

The control system for keeping the fixed-point of ships against disturbance was designed by applying an ILQ (Inverse Linear Quadratic) control (possible to specify the response of controlled systems with time constant) theory, to study the effect of different time constants as design parameter on a fixed-point keeping performance. It was assumed that the controlled ship is equipped with two bow thrusters and one stern thruster of 30ton in output to generate a control force. For fixed-point keeping control, the state equation was derived to slave the controlled system to a target input. The ILQ design method uses the result of the inverse problem of optimum regulators. For designing control systems by using the ILQ control theory, the smallest time constant should be selected according to the most severe disturbance condition considering the response performance of controllers, to achieve fixed-point keeping of ships. In fixed-point keeping, it is also essential to put the initial position as close as possible to the target point. 2 refs., 6 figs., 2 tabs.

Exacerbation of Brain Injury by Post-Stroke Exercise Is Contingent Upon Exercise Initiation Timing

Directory of Open Access Journals (Sweden)

Fengwu Li

2017-10-01

Full Text Available Accumulating evidence has demonstrated that post-stroke physical rehabilitation may reduce morbidity. The effectiveness of post-stroke exercise, however, appears to be contingent upon exercise initiation. This study assessed the hypothesis that very early exercise exacerbates brain injury, induces reactive oxygen species (ROS generation, and promotes energy failure. A total of 230 adult male Sprague-Dawley rats were subjected to middle cerebral artery (MCA occlusion for 2 h, and randomized into eight groups, including two sham injury control groups, three non-exercise and three exercise groups. Exercise was initiated after 6 h, 24 h and 3 days of reperfusion. Twenty-four hours after completion of exercise (and at corresponding time points in non-exercise controls, infarct volumes and apoptotic cell death were examined. Early brain oxidative metabolism was quantified by examining ROS, ATP and NADH levels 0.5 h after completion of exercise. Furthermore, protein expressions of angiogenic growth factors were measured in order to determine whether post-stroke angiogenesis played a role in rehabilitation. As expected, ischemic stroke resulted in brain infarction, apoptotic cell death and ROS generation, and diminished NADH and ATP production. Infarct volumes and apoptotic cell death were enhanced (p < 0.05 by exercise that was initiated after 6 h of reperfusion, but decreased by late exercise (24 h, 3 days. This exacerbated brain injury at 6 h was associated with increased ROS levels (p < 0.05, and decreased (p < 0.05 NADH and ATP levels. In conclusion, very early exercise aggravated brain damage, and early exercise-induced energy failure with ROS generation may underlie the exacerbation of brain injury. These results shed light on the manner in which exercise initiation timing may affect post-stroke rehabilitation.

Mono and bimetallic nanoparticles of gold, silver and palladium-catalyzed NADH oxidation-coupled reduction of Eosin-Y

International Nuclear Information System (INIS)

Santhanalakshmi, J.; Venkatesan, P.

2011-01-01

Mono metallic (Au, Ag, Pd) and bimetallic (Au–Ag, Ag–Pd, Au–Pd) with 1:1 mol stoichiometry, nanoparticles are synthesized using one-pot, temperature controlled chemical method using cetyltrimethylammonium bromide (CTAB) as the capping agent. The particle sizes (Au = 5.6, Ag = 5.0, Pd = 6.0, Au–Ag = 9.2, Ag–Pd = 9.6, Au–Pd = 9.4 nm) are characterized by UV–Vis, HRTEM, and XRD measurements, respectively. CTAB bindings onto mono and bimetallic nanoparticles are analyzed by FTIR spectra. The catalytic activities of mono and bimetallic nanoparticles are tested on the reaction between NADH oxidation and Eosin-Y reduction. The effects of base, pH, ionic strength, nature of mono and bimetallic catalysts are studied and the reaction conditions are optimized. Bimetallic nanoparticles exhibited better catalysis than the mono metallic nanoparticles, which may be due to the electronic effects of the core to shell metal atoms.Graphical Abstract

Analysis of COMS-1 North-South Station Keeping Method

Directory of Open Access Journals (Sweden)

Hae-Yeon Kim

2005-12-01

Full Text Available The perturbations caused by the Sun and the Moon are predominantly out-of-plane effects causing a change in the inclination and in the right ascension of ascending node of a geostationary satellite. Due to the change of the inclination, subsatellite latitude of the geostationary satellite has a daily variations of the same magnitude of the inclination. Therefore we need a facility to control the orbital inclination and right ascension of ascending node for maintaining the satellite position in specified subsatellite latitude boundary using thrusters. In this paper we studied North-South station keeping strategies of the COMS-1 such as Track-Back Chord Target (TBCT method, Maximum Compensation Target (MCT method and Minimum Fuel Target (MFT method. We accomplished those North-South station keeping maneuvers for one year starting from December 2008. The required velocity increments to maintain the satellite are estimated as MCT 52.6065m/s, TBCT 52.2383m/s, MFT 51.5428m/s, respectively. We demonstrated that TBCT and MFT methods are proper to North-South station keeping for COMS-1. MFT method showed the minimum required velocity increments whereas TBCT traced narrow inclination boundary area for North-South station keeping.

Art, science, or both? Keeping the care in nursing.

Science.gov (United States)

Jasmine, Tayray

2009-12-01

Nursing is widely considered as an art and a science, wherein caring forms the theoretical framework of nursing. Nursing and caring are grounded in a relational understanding, unity, and connection between the professional nurse and the patient. Task-oriented approaches challenge nurses in keeping care in nursing. This challenge is ongoing as professional nurses strive to maintain the concept, art, and act of caring as the moral center of the nursing profession. Keeping the care in nursing involves the application of art and science through theoretical concepts, scientific research, conscious commitment to the art of caring as an identity of nursing, and purposeful efforts to include caring behaviors during each nurse-patient interaction. This article discusses the profession of nursing as an art and a science, and it explores the challenges associated with keeping the care in nursing.

A highly sensitive electrochemical sensor for simultaneous determination of hydroquinone and bisphenol A based on the ultrafine Pd nanoparticle@TiO2 functionalized SiC

International Nuclear Information System (INIS)

Yang, Long; Zhao, Hui; Fan, Shuangmei; Li, Bingchan; Li, Can-Peng

2014-01-01

Graphical abstract: The illustration of Pd@TiO 2 –SiC nanohybrids simultaneous sensing hydroquinone and bisphenol A by an electrochemical strategy. - Highlights: • TiO 2 –SiC was successfully prepared by a facile generic in situ growth strategy. • Ultrafine Pd NPs with a uniform size of ∼2.3 nm monodispersed on TiO 2 –SiC surface. • Electrochemical simultaneous determination of HQ and BPA was established. • Ultrafine metal NPs@metal oxide–SiC may be extended to other applications. - Abstract: A titanium dioxide–silicon carbide nanohybrid (TiO 2 –SiC) with enhanced electrochemical performance was successfully prepared through a facile generic in situ growth strategy. Monodispersed ultrafine palladium nanoparticles (Pd NPs) with a uniform size of ∼2.3 nm were successfully obtained on the TiO 2 –SiC surface via a chemical reduction method. The Pd-loaded TiO 2 –SiC nanohybrid (Pd@TiO 2 –SiC) was characterized by transmission electron microscopy and X-ray diffractometry. A method for the simultaneous electrochemical determination of hydroquinone (HQ) and bisphenol A (BPA) using a Pd@TiO 2 –SiC nanocomposite-modified glassy carbon electrode was established. Utilizing the favorable properties of Pd NPs, the Pd@TiO 2 –SiC nanohybrid-modified glassy carbon electrode exhibited electrochemical performance superior to those of TiO 2 –SiC and SiC. Differential pulse voltammetry was successfully used to simultaneously quantify HQ and BPA within the concentration range of 0.01–200 μM under optimal conditions. The detection limits (S/N = 3) of the Pd@TiO 2 –SiC nanohybrid electrode for HQ and BPA were 5.5 and 4.3 nM, respectively. The selectivity of the electrochemical sensor was improved by introducing 10% ethanol to the buffer medium. The practical application of the modified electrode was demonstrated by the simultaneous detection of HQ and BPA in tap water and wastewater samples. The simple and straightforward strategy presented in this

Is improved lane keeping during cognitive load caused by increased physical arousal or gaze concentration toward the road center?

Science.gov (United States)

Li, Penghui; Markkula, Gustav; Li, Yibing; Merat, Natasha

2018-08-01

Driver distraction is one of the main causes of motor-vehicle accidents. However, the impact on traffic safety of tasks that impose cognitive (non-visual) distraction remains debated. One particularly intriguing finding is that cognitive load seems to improve lane keeping performance, most often quantified as reduced standard deviation of lateral position (SDLP). The main competing hypotheses, supported by current empirical evidence, suggest that cognitive load improves lane keeping via either increased physical arousal, or higher gaze concentration toward the road center, but views are mixed regarding if, and how, these possible mediators influence lane keeping performance. Hence, a simulator study was conducted, with participants driving on a straight city road section whilst completing a cognitive task at different levels of difficulty. In line with previous studies, cognitive load led to increased physical arousal, higher gaze concentration toward the road center, and higher levels of micro-steering activity, accompanied by improved lane keeping performance. More importantly, during the high cognitive task, both physical arousal and gaze concentration changed earlier in time than micro-steering activity, which in turn changed earlier than lane keeping performance. In addition, our results did not show a significant correlation between gaze concentration and physical arousal on the level of individual task recordings. Based on these findings, various multilevel models for micro-steering activity and lane keeping performance were conducted and compared, and the results suggest that all of the mechanisms proposed by existing hypotheses could be simultaneously involved. In other words, it is suggested that cognitive load leads to: (i) an increase in arousal, causing increased micro-steering activity, which in turn improves lane keeping performance, and (ii) an increase in gaze concentration, causing lane keeping improvement through both (a) further increased micro

Being@: keep company with electronic evidence!

NARCIS (Netherlands)

Kooistra, J.; Hopstaken, Kees

2000-01-01

The title heading this paper Being@ keep company with electronic evedence is referring to an university training on the Internet which is processing insight into how science 'works' (in the active sense of the word) under the articulation of information- and communication technology (ICT) and

Formation of W(3)A(1) electron-transferring flavoprotein (ETF) hydroquinone in the trimethylamine dehydrogenase x ETF protein complex.

Science.gov (United States)

Jang, M H; Scrutton, N S; Hille, R

2000-04-28

The electron-transferring flavoprotein (ETF) from Methylophilus methylotrophus (sp. W(3)A(1)) exhibits unusual oxidation-reduction properties and can only be reduced to the level of the semiquinone under most circumstances (including turnover with its physiological reductant, trimethylamine dehydrogenase (TMADH), or reaction with strong reducing reagents such as sodium dithionite). In the present study, we demonstrate that ETF can be reduced fully to its hydroquinone form both enzymatically and chemically when it is in complex with TMADH. Quantitative titration of the TMADH x ETF protein complex with sodium dithionite shows that a total of five electrons are taken up by the system, indicating that full reduction of ETF occurs within the complex. The results indicate that the oxidation-reduction properties of ETF are perturbed upon binding to TMADH, a conclusion further supported by the observation of a spectral change upon formation of the TMADH x ETF complex that is due to a change in the environment of the FAD of ETF. The results are discussed in the context of ETF undergoing a conformational change during formation of the TMADH x ETF electron transfer complex, which modulates the spectral and oxidation-reduction properties of ETF such that full reduction of the protein can take place.

An azoreductase, aerobic NADH-dependent flavoprotein discovered from Bacillus sp.: functional expression and enzymatic characterization.

Science.gov (United States)

Ooi, Toshihiko; Shibata, Takeshi; Sato, Reiko; Ohno, Hiroaki; Kinoshita, Shinichi; Thuoc, Tran Linh; Taguchi, Seiichi

2007-05-01

The gene coding for an azoreductase, designated as an azrA, was cloned by polymerase chain reaction amplification from the genomic DNA of Bacillus sp. strain B29 isolated from soil. The azrA encoded a protein of 208 amino acids with calculated molecular mass of 22,766 Da. The enzyme was heterologously expressed in Escherichia coli with a strong band of 23 kDa on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Purified recombinant AzrA was a homodimer with a native molecular mass of 48 kDa containing two molecules of flavin mononucleotide (FMN; oxidized). This activity was oxygen insensitive and was nicotinamide adenine dinucleotide (reduced form; NADH) dependent. Recombinant AzrA exhibited a broad pH stability between 6 and 10 with a temperature optimum of 60-80 degrees C. The enzyme cleaved the model azo compound of methyl red [MR, 4'-(dimethylamino)-azobenzene-2-carboxylic acid] into 2-aminobenzoic acid and N, N'-dimethyl-p-phenylenediamine by ping-pong mechanism. The enzyme was not only able to decolorize MR but also able to decolorize sulfonated azo dyes such as Orange I and Acid Red 88.

Size controlled synthesis of biocompatible gold nanoparticles and their activity in the oxidation of NADH

International Nuclear Information System (INIS)

Chandran, Parvathy R; Sandhyarani, N; Naseer, M; Udupa, N

2012-01-01

Size and shape controlled synthesis remains a major bottleneck in the research on nanoparticles even after the development of different methods for their preparation. By tuning the size and shape of a nanoparticle, the intrinsic properties of the nanoparticle can be controlled leading tremendous potential applications in different fields of science and technology. We describe a facile route for the one pot synthesis of gold nanoparticles in water using monosodium glutamate as the reducing and stabilizing agent in the absence of seed particles. The particle diameter can be easily controlled by varying the pH of the reaction medium. Nanoparticles were characterized using scanning electron microscopy, UV–vis absorption spectroscopy, cyclic voltammetry, and dynamic light scattering. Zeta potential measurements were made to compare the stability of the different nanoparticles. The results suggest that lower pH favours a nucleation rate giving rise to smaller particles and higher pH favours a growth rate leading to the formation of larger particles. The synthesized nanoparticles are found to be stable and biocompatible. The nanoparticles synthesized at high pH exhibited a good electrocatalytic activity towards oxidation of nicotinamide adenine dinucleotide (NADH).

Keeping checkpoint/restart viable for exascale systems.

Energy Technology Data Exchange (ETDEWEB)

Riesen, Rolf E.; Bridges, Patrick G. (IBM Research, Ireland, Mulhuddart, Dublin); Stearley, Jon R.; Laros, James H., III; Oldfield, Ron A.; Arnold, Dorian (University of New Mexico, Albuquerque, NM); Pedretti, Kevin Thomas Tauke; Ferreira, Kurt Brian; Brightwell, Ronald Brian

2011-09-01

Next-generation exascale systems, those capable of performing a quintillion (10{sup 18}) operations per second, are expected to be delivered in the next 8-10 years. These systems, which will be 1,000 times faster than current systems, will be of unprecedented scale. As these systems continue to grow in size, faults will become increasingly common, even over the course of small calculations. Therefore, issues such as fault tolerance and reliability will limit application scalability. Current techniques to ensure progress across faults like checkpoint/restart, the dominant fault tolerance mechanism for the last 25 years, are increasingly problematic at the scales of future systems due to their excessive overheads. In this work, we evaluate a number of techniques to decrease the overhead of checkpoint/restart and keep this method viable for future exascale systems. More specifically, this work evaluates state-machine replication to dramatically increase the checkpoint interval (the time between successive checkpoint) and hash-based, probabilistic incremental checkpointing using graphics processing units to decrease the checkpoint commit time (the time to save one checkpoint). Using a combination of empirical analysis, modeling, and simulation, we study the costs and benefits of these approaches on a wide range of parameters. These results, which cover of number of high-performance computing capability workloads, different failure distributions, hardware mean time to failures, and I/O bandwidths, show the potential benefits of these techniques for meeting the reliability demands of future exascale platforms.

Towards station-keeping using GPI controllers

DEFF Research Database (Denmark)

Jouffroy, Jerome

In this paper, we propose to use a Generalized Proportional-Integral controller for station-keeping of a ship. For output feedback, this has the advantage of not requiring the use of an asymptotic Luenberger or Kalman observer. After describing the methodology for the simple case of controlling...

The NRPB's new dosimeter and dose record keeping services

International Nuclear Information System (INIS)

Dennis, J.A.; Marshall, T.O.; Shaw, K.B.

1976-01-01

A new automated dosimeter and record keeping service which the National Radiological Protection Board (UK) intends to introduce in 1977 is described. The automated system, based on a thermoluminescent dosimeter, will be linked to a fully computerised record keeping system with automatic printing of dose records and Transfer Records operated at its Headquarters at Harwell. The new system will dispense with much manual labour which in the past has introduced inevitable errors and incurred increasing costs. (U.K.)

Global Kinetic Analysis of Mammalian E3 Reveals pH-dependent NAD+/NADH Regulation, Physiological Kinetic Reversibility, and Catalytic Optimum*

Science.gov (United States)

Moxley, Michael A.; Beard, Daniel A.; Bazil, Jason N.

2016-01-01

Mammalian E3 is an essential mitochondrial enzyme responsible for catalyzing the terminal reaction in the oxidative catabolism of several metabolites. E3 is a key regulator of metabolic fuel selection as a component of the pyruvate dehydrogenase complex (PDHc). E3 regulates PDHc activity by altering the affinity of pyruvate dehydrogenase kinase, an inhibitor of the enzyme complex, through changes in reduction and acetylation state of lipoamide moieties set by the NAD+/NADH ratio. Thus, an accurate kinetic model of E3 is needed to predict overall mammalian PDHc activity. Here, we have combined numerous literature data sets and new equilibrium spectroscopic experiments with a multitude of independently collected forward and reverse steady-state kinetic assays using pig heart E3. The latter kinetic assays demonstrate a pH-dependent transition of NAD+ activation to inhibition, shown here, to our knowledge, for the first time in a single consistent data set. Experimental data were analyzed to yield a thermodynamically constrained four-redox-state model of E3 that simulates pH-dependent activation/inhibition and active site redox states for various conditions. The developed model was used to determine substrate/product conditions that give maximal E3 rates and show that, due to non-Michaelis-Menten behavior, the maximal flux is different compared with the classically defined kcat. PMID:26644471

Stock keeping unit fill rate specification

NARCIS (Netherlands)

Teunter, R. H.; Syntetos, A. A.; Babai, M. Z.

2017-01-01

The fill rate is the most widely applied service level measure in industry and yet there is minimal advice available on how it should be differentiated on an individual Stock Keeping Unit (SKU) basis given that there is an overall system target service level. The typical approach utilized in

Keeping all options open: Parents' approaches to advance care planning.

Science.gov (United States)

Beecham, Emma; Oostendorp, Linda; Crocker, Joanna; Kelly, Paula; Dinsdale, Andrew; Hemsley, June; Russell, Jessica; Jones, Louise; Bluebond-Langner, Myra

2017-08-01

Early engagement in advance care planning (ACP) is seen as fundamental for ensuring the highest standard of care for children and young people with a life-limiting condition (LLC). However, most families have little knowledge or experience of ACP. To investigate how parents of children and young people with LLCs approach and experience ACP. Open-ended, semi-structured interviews were conducted with parents of 18 children; nine children who were currently receiving palliative care services, and nine children who had received palliative care and died. Verbatim transcripts of audiotaped interviews were analysed following principles of grounded theory while acknowledging the use of deductive strategies, taking account of both the child's condition, and the timing and nature of decisions made. Parents reported having discussions and making decisions about the place of care, place of death and the limitation of treatment. Most decisions were made relatively late in the illness and by parents who wished to keep their options open. Parents reported different levels of involvement in a range of decisions; many wished to be involved in decision making but did not always feel able to do so. This study highlights that parents' approaches to decision making vary by the type of decision required. Their views may change over time, and it is important to allow them to keep their options open. We recommend that clinicians have regular discussions over the course of the illness in an effort to understand parents' approaches to particular decisions rather than to drive to closure prematurely. © 2016 The Authors Health Expectations Published by John Wiley & Sons Ltd.

JS-III-49, a hydroquinone derivative, exerts anti-inflammatory activity by targeting Akt and p38.

Science.gov (United States)

Yi, Young-Su; Kim, Mi-Yeon; Cho, Jae Youl

2017-05-01

Since previous studies have reported that hydroquinone (HQ) exerted immunosuppressive and anti-inflammatory activity, various HQ derivatives have been synthesized and their biological activities investigated. In this study, we explored the anti-inflammatory activity of JS-III-49, a novel HQ derivative, in macrophage-mediated inflammatory responses. JS-III-49 suppressed the production of the inflammatory mediators nitric oxide (NO) and prostaglandin E 2 (PGE 2 ) and down-regulated the mRNA expression of the inflammatory enzymes cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) as well as the expression of the pro-inflammatory cytokines interleukin-6 (IL-6) and IL-1b without cytotoxicity in LPS-stimulated RAW264.7 cells. JS-III-49 inhibited nuclear translocation of the NF-kB transcription factors p65 and p50 by directly targeting Akt, an upstream kinase of the NF-kB pathway, in LPS-stimulated RAW264.7 cells. However, JS-III-49 did not directly inhibit the kinase activities of Src and Syk, which are upstream kinases of Akt, in LPS-stimulated RAW264.7 cells. Moreover, JS-III-49 suppressed the nuclear translocation of c-Fos, one of the components of AP-1, by specifically targeting p38, an upstream mitogen-activated protein kinase (MAPK) in the AP-1 pathway in LPS-stimulated RAW264.7 cells. These results suggest that JS-III-49 plays an anti-inflammatory role in LPS-stimulated macrophages by targeting Akt and p38 in the NF-kB and AP-1 pathways, respectively.

INTERNATIONAL PEACE-KEEPING OPERATION: A BREACH OF ...

African Journals Online (AJOL)

Mofasony

Observer group activity was resumed after the wars of 1956, 1967 and 1973. .... International peacekeeping examines the theory and practice of peace-keeping .... U.O. Umozurike, Introduction to International Law, Spectrum Law Publishing, ...

Keep the best of your life

NARCIS (Netherlands)

Stultiens, Andrea

Keep the Best of Your Life (for the Rest of Your Life) is part Making Oneself ‘a twofold exhibition of both historical investigations and contemporary showcases of photo studio practises in South and Southeast Asia and Uganda.’ ‘Making Oneself’ was one exhibitions of the Noorderlicht Photo festival

40 CFR 63.1456 - What records must I keep and how long must I keep my records?

Science.gov (United States)

2010-07-01

... following the date of each occurrence, measurement, maintenance, corrective action, report, or record. (d..., maintenance, corrective action, report, or record, according to § 63.10(b)(1). You can keep the records off... bag leak detection system. (ii) Description of the corrective actions taken following each bag leak...

Characterization of 12-molybdophosphoric acid supported on mesoporous silica MCM-41 and its catalytic performance in the synthesis of hydroquinone diacetate

International Nuclear Information System (INIS)

Ahmed, Awad I.; Samra, S.E.; El-Hakam, S.A.; Khder, A.S.; El-Shenawy, H.Z.; El-Yazeed, W.S. Abo

2013-01-01

12-molybdophosphoric acid (PMA) was supported on mesoporous molecular sieves MCM-41 by impregnation of 12-molybdophosphoric acid followed by calcination. The nanochannels of MCM-41 provide a large surface area for the solid state dispersion of 12-molybdophosphoric acid. The samples have been characterized by N 2 adsorption–desorption at −196 °C, transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and FT-IR measurements. The acidity and catalytic activity have been, respectively, examined by nonaqueous titration of n-butylamine in acetonitrile and synthesis of hydroquinone diacetate. The results showed that ordered hexagonal pore structure was observed in the synthesized MCM-41. Also the results indicate that PMA are highly dispersed on mesoporous silica MCM-41 spherical nanoparticles while PMA retains its Keggin structure. On the other hand, with increasing the introduced PMA amount, the specific surface area decreases, and the mesoporous ordering of the samples become poor. Both the surface acidity and the catalytic activity sharply increase with the modification of MCM-41 by PMA but decrease by increasing the calcination temperature. The sample with 55 wt% PMA/MCM-41 calcined at 350 °C shows the highest acidity and catalytic activity.

Social and cognitive factors associated with children's secret-keeping for a parent.

Science.gov (United States)

Gordon, Heidi M; Lyon, Thomas D; Lee, Kang

2014-01-01

This study examined children's secret-keeping for a parent and its relation to trust, theory of mind, secrecy endorsement, and executive functioning (EF). Children (N = 107) between 4 and 12 years of age participated in a procedure wherein parents broke a toy and asked children to promise secrecy. Responses to open-ended and direct questions were examined. Overall, secret-keeping increased with age and promising to keep the secret was related to fewer disclosures in open-ended questioning. Children who kept the secret in direct questioning exhibited greater trust and better parental ratings of EF than children who disclosed the secret. Findings highlight the importance of both social and cognitive factors in secret-keeping development. © 2014 The Authors. Child Development © 2014 Society for Research in Child Development, Inc.

Web Tools: Keeping Learners on Pace

Science.gov (United States)

Kosloski, Mickey

2016-01-01

One of the greatest challenges in teaching technology and engineering is pacing. Some students grasp new technological concepts quickly, while others need repetition and may struggle to keep pace. This poses an obstacle for the technology and engineering teacher, and is particularly true when teaching students to build a website. However, there…

Longitudinal Associations between Keeping a Secret and Psychosocial Adjustment in Adolescence

Science.gov (United States)

Frijns, Tom; Finkenauer, Catrin

2009-01-01

Increasing bodies of evidence suggest that keeping secrets may be detrimental to well-being and adjustment, whereas confiding secrets may alleviate the detriments of secrecy and benefit well-being and adjustment. However, few studies have addressed the consequences of keeping and confiding secrets simultaneously, and even fewer have done so…

Modeling of the fatigue intragranular strain hardening of metals at high temperature with keeping up time; Modelisation de l'ecrouissage intragranulaire en fatigue des metaux a haute temperature avec temps de maintien

Energy Technology Data Exchange (ETDEWEB)

Sauzay, M.; Mottot, M.; Noblecourt, M.; Allais, L.; Monnet, I.; Perinet, J. [CEA Saclay, Service de Recherche en Metallurgie Appliquee, DMN/SRMA, 91 - Gif-sur-Yvette (France)

2003-07-01

This study aims at foreseeing the behaviour of some alloys during high temperature fatigue-relaxation (creep) conditions when the maximum deformation is maintained during long times (about a month for each cycle). Such experiments can hardly be performed with laboratory tests. A simple modeling of the restoration occurring during the keeping of the conditions of deformation can explain the absence of dislocation microstructures. Abstract only. (J.S.)

Blood Pressure Matters: Keep Hypertension in Check

Science.gov (United States)

... 2016 Print this issue Blood Pressure Matters Keep Hypertension in Check En español Send us your comments ... 1 in 3 adults in the U.S. has high blood pressure, but many don’t realize it. High blood ...

The level of menadione redox-cycling in pancreatic β-cells is proportional to the glucose concentration: role of NADH and consequences for insulin secretion.

Science.gov (United States)

Heart, Emma; Palo, Meridith; Womack, Trayce; Smith, Peter J S; Gray, Joshua P

2012-01-15

Pancreatic β-cells release insulin in response to elevation of glucose from basal (4-7mM) to stimulatory (8-16mM) levels. Metabolism of glucose by the β-cell results in the production of low levels of reactive oxygen intermediates (ROI), such as hydrogen peroxide (H(2)O(2)), a newly recognized coupling factor linking glucose metabolism to insulin secretion. However, high and toxic levels of H(2)O(2) inhibit insulin secretion. Menadione, which produces H(2)O(2) via redox cycling mechanism in a dose-dependent manner, was investigated for its effect on β-cell metabolism and insulin secretion in INS-1 832/13, a rat β-cell insulinoma cell line, and primary rodent islets. Menadione-dependent redox cycling and resulting H(2)O(2) production under stimulatory glucose exceeded several-fold those reached at basal glucose. This was paralleled by a differential effect of menadione (0.1-10μM) on insulin secretion, which was enhanced at basal, but inhibited at stimulatory glucose. Redox cycling of menadione and H(2)O(2) formation was dependent on glycolytically-derived NADH, as inhibition of glycolysis and application of non-glycogenic insulin secretagogues did not support redox cycling. In addition, activity of plasma membrane electron transport, a system dependent in part on glycolytically-derived NADH, was also inhibited by menadione. Menadione-dependent redox cycling was sensitive to the NQO1 inhibitor dicoumarol and the flavoprotein inhibitor diphenylene iodonium, suggesting a role for NQO1 and other oxidoreductases in this process. These data may explain the apparent dichotomy between the stimulatory and inhibitory effects of H(2)O(2) and menadione on insulin secretion. Published by Elsevier Inc.

Principles of record keeping for decommissioning purposes

International Nuclear Information System (INIS)

Laraia, M.

2003-01-01

At the siting and conceptual design stage of a nuclear facility the first records pertaining to that facility are produced and stored. Subsequent phases in the facility's life cycle (detailed design, construction, commissioning, operation and shutdown) will include the production and retention of a large variety of records. Design, as-built drawings and operational records are essential for safe and efficient operation of any nuclear facility. This set of records is constantly updated and augmented during operation. Records from all phases of a nuclear facility are important for planning its decommissioning. Although not all of these records need to be included explicitly in the decommissioning plan itself, the process of initial, ongoing and final planning utilizes pertinent records for, and ultimately achieves, safe and cost effective decommissioning. When a nuclear facility is shutdown for decommissioning, current operating experience may be lost. Therefore, one important element of planning is to identify, secure and store appropriate operational records to support decommissioning. This process is preferably initiated during the design and construction phase and continues throughout operation including shutdown. Part of the records inventory from operation will become records for decommissioning and it is cost effective to identify these records before final facility shutdown. Experience shows that lack of attention to record keeping may result in an undue waste of time, other resources and additional costs. The newly established Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management recognizes the importance of keeping decommissioning-related records. In addition, the systematic management of records is an essential part of quality assurance and is often a licence condition. A good comprehensive decommissioning records management system (RMS) is one specific application of the broader concepts of 'Protection

A Remote Social Robot to Motivate and Support Diabetic Children in Keeping a Diary

NARCIS (Netherlands)

Drift, E.J.G. van der; Looije, R.; Blanson Henkemans, O.A.; Neerincx, M.A.

2014-01-01

Children with diabetes can benefit from keeping a diary, but seldom keep one. Within the European ALIZ-E project a robot companion is being developed that, among other things, will be able to support and motivate diabetic children to keep a diary. This paper discusses the study of a robot supporting

A remote social robot to motivate and support diabetic children in keeping a diary

NARCIS (Netherlands)

Van Der Drift, Esther J G; Beun, Robbert Jan; Looije, Rosemarijn; Henkemans, Oliver A Blanson; Neerincx, Mark A.

2014-01-01

Children with diabetes can benefit from keeping a diary, but seldom keep one. Within the European ALIZ-E project a robot companion is being developed that, among other things, will be able to support and motivate diabetic children to keep a diary. This paper discusses the study of a robot supporting

N.R.P.B.'s new record-keeping service and thermoluminescent dosemeter

International Nuclear Information System (INIS)

Dennis, J.A.; Marshall, T.O.; Shaw, K.B.; Kendall, G.M.

1977-01-01

With the approval of the Health and Safety Executive the National Radiological Protection Board is introducing a radiation dose record keeping service in association with a thermoluminescent dosimeter. This service will relieve employers of the responsibility for maintaining and keeping dose records. Both the record keeping and dosimeter systems are described, including the documents which will be produced for employers. The thermoluminescent dosimeter is more accurate and less sensitive to environmental factors than the film dosimeter, which it replaces. It also reduces the consumption of materials and, with automated processing, is labour saving. (author)

KEEP Language Research Strategy. Technical Report #14.

Science.gov (United States)

Tharp, Roland G.; Gallimore, Ronald

This paper outlines the strategies of Kamehameha Early Education Program (KEEP) language research, and briefly reviews the findings through Spring 1974. A major research emphasis has been placed on the assessment of Standard English comptence of Hawaii school children. (CM)

Keeping fat on time

DEFF Research Database (Denmark)

Ninel Hansen, Stine; Peics, Julia; Gerhart-Hines, Zachary

2017-01-01

Circadian clocks harmonize processes ranging from intracellular biochemistry to whole-body physiology in accordance with the Earth's 24h rotation. These intrinsic oscillators are based on an interlocked transcriptional-translational feedback loop comprised from a set of core clock factors. In add...

Social and cognitive factors associated with children’s secret-keeping for a parent

Science.gov (United States)

Gordon, Heidi M.; Lyon, Thomas D.; Lee, Kang

2014-01-01

This study examined children’s secret-keeping for a parent and its relationship to trust, theory of mind, secrecy endorsement, and executive functioning (EF). Children (N = 107) between 4 and 12 years of age participated in a procedure wherein parents broke a toy and asked children to promise secrecy. Responses to open-ended and direct questions were examined. Overall, secret-keeping increased with age and promising to keep the secret was related to fewer disclosures in open-ended questioning. Children who kept the secret in direct questioning exhibited greater trust and better parental ratings of EF than children who disclosed the secret. Findings highlight the importance of both social and cognitive factors in secret-keeping development. PMID:25291258

Spectral and time-resolved studies on ocular structures

Science.gov (United States)

Schweitzer, D.; Jentsch, S.; Schenke, S.; Hammer, M.; Biskup, C.; Gaillard, E.

2007-07-01

Measurements of endogeous fluorophores open the possibility for evaluation of metabolic state at the eye. For interpretation of 2-dimensional measurements of time-resolved auto fluorescence in 2 separate spectral ranges at the human eye, comparing measurements were performed on porcine eyes. Determining excitation and emission spectra, attention was drawn of proof of coenzymes NADH and FAD in isolated anatomical structures cornea, aqueous humor, lens, vitreous, neuronal retina, retinal pigment epithelium (RPE), choroid, and sclera. All these structures exhibit auto fluorescence, highest in lens. Excitation at 350 nm results in local fluorescence maxima at 460 nm, corresponding to NADH, in all structures. This short-wave excitation allows metabolic studies only at the anterior eye, because of the limited transmission of the ocular media. During excitation at 446 nm the existence of FAD is expressed by local fluorescence maxima at 530 nm. The composition fluorescence spectra allow no discrimination between single ocular structures. Approximating the dynamic fluorescence by a double exponential function, the shortest lifetimes were detected in RPE and neuronal retina. The histograms of mean lifetime t M cover each other on lens with cornea and also on sclera with choroid. Despite the lifetimes are close between RPE and neuronal retina, the relative contributions Q I are wide different. The gradient of trend lines in cluster diagrams of amplitudes α II vs. α I allows a discrimination of ocular structures.

NRPB TLD and dose record keeping service - further progress

International Nuclear Information System (INIS)

Greenslade, E.

1979-01-01

Various aspects of the National Radiological Protection Board's service are described. An increasing number of UK employers are transferring from film monitors, and record keeping is now provided for both large and small groups of workers. Data entry directly from punched cards prepared by the larger employers has reduced initial costs and therefore carries a reduced registration fee for these users. Computerized dose record keeping allows automatic retrieval of cumulative dose information from any NRPB record of previous employment, thus safeguarding itinerant workers. Warning Dose Reports are issued automatically when cumulative dose totals reach or exceed 60% of a limit, or when a dose rate greater than 0.1 rem per 4 weeks is recorded. Flexibility in wearing period results in dosemeter economy and reduces laboratory work load. High recorded doses can be checked by UV stimulation of both disks to confirm the accuracy of the previous measurement. Employers are provided with a comprehensive and accurate monitoring package, fulfilling HSE requirements and exempting employers from their former responsibility to keep their own comprehensive records. (UK)

Cytochrome b5 and NADH cytochrome b5 reductase: genotype-phenotype correlations for hydroxylamine reduction.

Science.gov (United States)

Sacco, James C; Trepanier, Lauren A

2010-01-01

NADH cytochrome b5 reductase (b5R) and cytochrome b5 (b5) catalyze the reduction of sulfamethoxazole hydroxylamine (SMX-HA), which can contribute to sulfonamide hypersensitivity, to the parent drug sulfamethoxazole. Variability in hydroxylamine reduction could thus play a role in adverse drug reactions. The aim of this study was to characterize variability in SMX-HA reduction in 111 human livers, and investigate its association with single nucleotide polymorphisms (SNPs) in b5 and b5R cDNA. Liver microsomes were assayed for SMX-HA reduction activity, and b5 and b5R expression was semiquantified by immunoblotting. The coding regions of the b5 (CYB5A) and b5R (CYB5R3) genes were resequenced. Hepatic SMX-HA reduction displayed a 19-fold range of individual variability (0.06-1.11 nmol/min/mg protein), and a 17-fold range in efficiency (Vmax/Km) among outliers. SMX-HA reduction was positively correlated with b5 and b5R protein content (Phydroxylamine reduction activities, these low-frequency cSNPs seem to only minimally impact overall observed phenotypic variability. Work is underway to characterize polymorphisms in other regions of these genes to further account for individual variability in hydroxylamine reduction.

GC electrode modified with carbon nanotubes and NiO for the simultaneous determination of bisphenol A, hydroquinone and catechol

International Nuclear Information System (INIS)

Goulart, Lorena Athie; Mascaro, Lucia Helena

2016-01-01

This work reports the electrochemical determination of bisphenol A (BPA), hydroquinone (HQ) and catechol (CC) using glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes (MWCNT) and nickel oxide nanoparticles (NiO). MWCNT were functionalized with sulfonitric solution (3H 2 SO 4 :1HNO 3 ) and dispersed in dimethylformamide for the MWCNT/GCE manufacturing. The MWCNT/GCE was modified with NiO using cyclic potential in pH 4 maintained by an acetate buffer solution containing 0.008 mol L −1 of nickel nitrate. The concentration of the nickel solution and the number of cycles in the electrodeposition were studied. Morphological characterization of NiO/MWCNT/GCE was carried out by scanning electron microscopy and the presence of NiO was observed. The electrochemical behavior was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy using BPA solution and the results were compared with those of GCE. The NiO/MWCNT/GCE presented the lowest charge transfer resistance. The electrochemical detection of BPA, HQ and CC was developed using differential pulse voltammetry. The analytical curves showed an excellent linear response and the detection limits for the simultaneous determination of BPA, HQ and CC were 2.8 × 10 −8 mol L −1 , 2.70 × 10 −8 mol L −1 and 5.9 × 10 −8 mol L −1 , respectively.

Synthesis of nitrogen-doped activated graphene aerogel/gold nanoparticles and its application for electrochemical detection of hydroquinone and o-dihydroxybenzene

Science.gov (United States)

Juanjuan, Zhang; Ruiyi, Li; Zaijun, Li; Junkang, Liu; Zhiguo, Gu; Guangli, Wang

2014-04-01

Graphene aerogel materials have attracted increasing attention owing to their large specific surface area, high conductivity and electronic interactions. Here, we report for the first time a novel strategy for the synthesis of nitrogen-doped activated graphene aerogel/gold nanoparticles (N-doped AGA/GNs). First, the mixture of graphite oxide, 2,4,6-trihydroxybenzaldehyde, urea and potassium hydroxide was dispersed in water and subsequently heated to form a graphene oxide hydrogel. Then, the hydrogel was dried by freeze-drying and reduced by thermal annealing in an Ar/H2 environment in sequence. Finally, GNs were adsorbed on the surface of the N-doped AGA. The resulting N-doped AGA/GNs offers excellent electronic conductivity (2.8 × 103 S m-1), specific surface area (1258 m2 g-1), well-defined 3D hierarchical porous structure and apparent heterogeneous electron transfer rate constant (40.78 +/- 0.15 cm s-1), which are notably better than that of previous graphene aerogel materials. Moreover, the N-doped AGA/GNs was used as a new sensing material for the electrochemical detection of hydroquinone (HQ) and o-dihydroxybenzene (DHB). Owing to the greatly enhanced electron transfer and mass transport, the sensor displays ultrasensitive electrochemical response to HQ and DHB. Its differential pulse voltammetric peak current linearly increases with the increase of HQ and DHB in the range of 5.0 × 10-8 to 1.8 × 10-4 M for HQ and 1 × 10-8 to 2.0 × 10-4 M for DHB. The detection limit is 1.5 × 10-8 M for HQ and 3.3 × 10-9 M for DHB (S/N = 3). This method provides the advantage of sensitivity, repeatability and stability compared with other HQ and DHB sensors. The sensor has been successfully applied to detection of HQ and DHB in real water samples with the spiked recovery in the range of 96.8-103.2%. The study also provides a promising approach for the fabrication of various graphene aerogel materials with improved electrochemical performances, which can be potentially

Fresh-keeping of mushroom by irradiation

International Nuclear Information System (INIS)

Liu Chao; Xu Hongqing; Wang Hong; Cai Jian

2003-01-01

The effect of 60 Co γ irradiation on the preservation of Agaricus bisporus were studied. The results showed that after irradiation the mushroom had lower rates of membrane split, opening of pilei, browning, decomposition and lose of fresh weight. The fresh keeping period of mushroom irradiated with 1.2 kGy and stored at 4 degree C was prolonged to 30 days

Project in fiscal 1988 for research and development of basic technologies in next generation industries. Achievement report on research and development of bio-reactors; 1988 nendo bio reactor no kenkyu kaihatsu seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1989-03-01

Research and development has been performed on bio-reactors to substitute the oxidizing reaction process, and on reduction reacting bio-reactors to fix the coenzyme regeneration system. This paper summarizes the achievements in fiscal 1988. In the research of a bio-reactor using bacteria that produce muconic acid from benzoic acid, stable productivity of 60 g/L/day or more was obtained. In the research of a multi-phase based bio-reactor composed of air, oil, water and biomass, discussions were given on the phase inverting film permeation type reactor. In the research of a bio-reactor to produce acetic acid from carbon dioxide and hydrogen, productivity of 149 g/L/day as maximum was achieved by enhancing the production speed by means of pressurization. In the research of a bio-reactor to produce hydroquinone from phenol, up-keeping the duration for 100 hours or longer has become possible at the hydroquinone production speed of 3 g/L/h. In the research of a reduction-based bio-reactor incorporating the regeneration system of coenzyme NAD(P)H, discussions were given on optimizing the continuous enzymatic reaction in the production of sorbitol. (NEDO)

Effect of milk temperature during irradiation on total bacterial count and keeping quality

International Nuclear Information System (INIS)

Sabbour, M.M.; Dawod, A.H.; Newigy, N.A.; Wahab, G.A.M.

1989-01-01

Cows' and buffaloes' milk samples were exposed to different doses of gamma radiation (100, 200 and 300 Kr) at 10 and 30°C. Irradiation of milk at 10°C caused more reduction in total bacterial count than that occurred at 30°C. The rate of microbial destruction due to irradiation at 10°C was higher than that occurred at 30°C. The keeping quality was determined daily for 15 days by clot-on-boiling test for samples kept at room temperature and in a refrigerator. The keeping quality recorded for cows' and buffaloes' milk samples in the refrigerator was 4 days, while it was only 1 day at room temperature. Irradiation of milk at 10°C was more effective than irradiation at 30°C, to increase the keeping quality of irradiated milk kept at refrigeration. Irradiation of milk samples at 10°C by 200 Kr increased the keeping quality for two weeks in the refrigerator, i.e. such a treatment increased the keeping quality by 4 folds

Real time monitoring of rat liver energy state during ischemia.

Science.gov (United States)

Barbiro, E; Zurovsky, Y; Mayevsky, A

1998-11-01

Hepatic failure is one of the major problems developed during the posttransplantation period. A possible cause of hepatic failure is the prolonged ischemia induced during the implantation procedure. Hepatic ischemia leads to a reduction in oxygen supply, ATP level decline, liver metabolism impairment, and finally organ failure. The purpose of this study was to estimate the functional state of the liver by monitoring liver blood flow and the mitochondrial NADH redox state simultaneously and continuously during in situ liver ischemia followed by reperfusion. Measurements were performed using the multiprobe developed in our laboratory consisting of fibers for the measurement of relative liver blood flow (laser Doppler flowmetry) and mitochondrial redox state (NADH fluorescence). The experimental procedure included the temporary interruption of blood flow to the liver using three types of ischemia, hepatic artery occlusion, portal vein occlusion, and simultaneous occlusion of hepatic artery and portal vein, followed by a reperfusion period. These preliminary experiments showed a significant decrease in liver blood flow, following the three types of liver ischemia, and a significant increase in NADH levels. The probe used in this study incorporates the advantage of monitoring NADH and liver blood flow simultaneously and continuously from the same area on the surface of the liver. Since each of these two parameters is not calibrated in absolute units, the simultaneous monitoring decreases possible artifacts. Also, it will allow us to determine of the coupling between tissue blood flow and oxidative phosphorylation. It is believed that the measurements of respiratory chain dysfunction might predict organ viability in clinical organ transplantation situations. Using this probe may also help to decrease the variability in liver blood flow monitoring since liver blood flow monitoring is supported simultaneously with the mitochondrial redox state, which supplies the

Development of a Real-time PCR test for porcine group A rotavirus diagnosis

OpenAIRE

Marconi, Elizabeth C.M.; Bernardes, Nara T.C.G.; Beserra, Laila A.R.; Silva, Fernanda D.F.; Gregori, Fabio

2015-01-01

Group A Rotavirus (RVA) is one of the most common causes of diarrhea in humans and several animal species. A SYBR-Green Real-Time polymerase chain reaction (PCR) was developed to diagnose RVA from porcine fecal samples, targeting amplification of a 137-bp fragment of nonstructural protein 5 (NSP5) gene using mRNA of bovine NADH-desidrogenase-5 as exogenous internal control. Sixty-five samples were tested (25 tested positive for conventional PCR and genetic sequencing). The overall agreement (...

Standardized Test Results: KEEP and Control Students. 1975-1976, Technical Report #69.

Science.gov (United States)

Antill, Ellen; Speidel, Gisela E.

This report presents the results of various standardized measures administered to Kamehameha Early Education Program (KEEP) students and control students in the school year 1975-1976. In contrast to previous comparisons, KEEP employed more rigorous procedures for the selection of the control students and for the conditions of test administration.…

Description of the KEEP Reading Curriculum, 1975-76. Technical Report No. 43.

Science.gov (United States)

Au, Kathryn H.

The Kamehameha Early Education Program (KEEP) is a research and development program designed to develop, demonstrate, and disseminate methods for improving the education of Hawaiian and part-Hawaiian children; this report contains a description of the reading curriculum used in the KEEP demonstration school during the 1975-76 school year. The…

30 CFR 210.40 - Will MMS keep the information I provide confidential?

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Will MMS keep the information I provide... MINERALS REVENUE MANAGEMENT FORMS AND REPORTS General Provisions § 210.40 Will MMS keep the information I provide confidential? The MMS will treat information obtained under this part as confidential to the...

Modification of glassy carbon electrode with poly(hydroxynaphthol blue)/multi-walled carbon nanotubes composite and construction a new voltammetric sensor for the simultaneous determination of hydroquinone, catechol, and resorcinol

Science.gov (United States)

Daneshinejad, Hassan; Arab Chamjangali, Mansour; Goudarzi, Nasser; Hossain Amin, Amir

2018-03-01

A novel voltammetric sensor is developed based on a poly(hydroxynaphthol blue)/multi-walled carbon nanotubes-modified glassy carbon electrode for the simultaneous determination of the dihydroxybenzene isomers hydroquinone (HQ), catechol (CC), and resorcinol (RS). The preparation and basic electrochemical performance of the sensor are investigated in details. The electrochemical behavior of the dihydroxybenzene isomers at the sensor is studied by the cyclic and differential pulse voltammetric techniques. The results obtained show that this new electrochemical sensor exhibits an excellent electro-catalytic activity towards oxidation of the three isomers. The mechanism of this electro-catalytic activity is discussed. Using the optimum parameters, limit of detection obtained 0.24, 0.24, and 0.26 μmol L-1 for HQ, CC, and RS, respectively. The modified electrode is also successfully applied to the simultaneous determination of dihydroxybenzene in water samples.

Time Error Analysis of SOE System Using Network Time Protocol

International Nuclear Information System (INIS)

Keum, Jong Yong; Park, Geun Ok; Park, Heui Youn

2005-01-01

To find the accuracy of time in the fully digitalized SOE (Sequence of Events) system, we used a formal specification of the Network Time Protocol (NTP) Version 3, which is used to synchronize time keeping among a set of distributed computers. Through constructing a simple experimental environments and experimenting internet time synchronization, we analyzed the time errors of local clocks of SOE system synchronized with a time server via computer networks

Cigarette smoke-related hydroquinone dysregulates MCP-1, VEGF and PEDF expression in retinal pigment epithelium in vitro and in vivo.

Directory of Open Access Journals (Sweden)

Marianne Pons

2011-02-01

Full Text Available Age-related macular degeneration (AMD is the leading cause of legal blindness in the elderly population. Debris (termed drusen below the retinal pigment epithelium (RPE have been recognized as a risk factor for dry AMD and its progression to wet AMD, which is characterized by choroidal neovascularization (CNV. The underlying mechanism of how drusen might elicit CNV remains undefined. Cigarette smoking, oxidative damage to the RPE and inflammation are postulated to be involved in the pathophysiology of the disease. To better understand the cellular mechanism(s linking oxidative stress and inflammation to AMD, we examined the expression of pro-inflammatory monocyte chemoattractant protein-1 (MCP-1, pro-angiogenic vascular endothelial growth factor (VEGF and anti-angiogenic pigment epithelial derived factor (PEDF in RPE from smoker patients with AMD. We also evaluated the effects of hydroquinone (HQ, a major pro-oxidant in cigarette smoke on MCP-1, VEGF and PEDF expression in cultured ARPE-19 cells and RPE/choroids from C57BL/6 mice.MCP-1, VEGF and PEDF expression was examined by real-time PCR, Western blot, and ELISA. Low levels of MCP-1 protein were detected in RPE from AMD smoker patients relative to controls. Both MCP-1 mRNA and protein were downregulated in ARPE-19 cells and RPE/choroids from C57BL/6 mice after 5 days and 3 weeks of exposure to HQ-induced oxidative injury. VEGF protein expression was increased and PEDF protein expression was decreased in RPE from smoker patients with AMD versus controls resulting in increased VEGF/PEDF ratio. Treatment with HQ for 5 days and 3 weeks increased the VEGF/PEDF ratio in vitro and in vivo.We propose that impaired RPE-derived MCP-1-mediated scavenging macrophages recruitment and phagocytosis might lead to incomplete clearance of proinflammatory debris and infiltration of proangiogenic macrophages which along with increased VEGF/PEDF ratio favoring angiogenesis might promote drusen accumulation and

Keep New Mexico Beautiful, Recycling Project Successful

Science.gov (United States)

Bickel, Victor R.

1975-01-01

Through the efforts of community groups, the support of local industries, and the state government, Keep New Mexico Beautiful, Inc. (KNMB) is now operating a large-scale recycling business. KNMB has been able to save tons of natural resources, provide local employment, and educate the public to this environmental concern. (MA)

Evidence Regarding Teaching and Assessment of Record-Keeping Skills in Training of Dental Students.

Science.gov (United States)

Amos, Kate J; Bearman, Margaret; Palermo, Claire

2015-10-01

The aim of this study was to assess the literature on teaching and assessing dental students' record-keeping skills prior to qualification to practice independently as a dentist. A systematic literature review was performed using Ovid MEDLINE and SCOPUS. Keywords used in the search included dental, record, audit, education, and assessment. Electronic search results were screened for publications that targeted undergraduate dental training, related to a record-keeping education intervention, and were published in English and available in full text. Six studies met the inclusion and exclusion criteria. Data extraction and quality assessment were performed, and research findings were compared across the included studies. These six articles addressed the techniques used to teach and assess record-keeping skills in a pre-qualification context. The techniques included supervisor audits, peer audits, lectures, tutorials, research assignments, case reports, record-keeping templates, and checklists of required record components. The use of record audit as part of teaching and evaluation dominated these articles; it was used as the assessment method in five of the six studies. All methods of record-keeping training in studies published to date were found effective in improving student record-keeping skills. However, there was insufficient evidence to determine whether certain methods were more effective than others.

41 CFR 102-34.345 - What records do we need to keep?

Science.gov (United States)

2010-07-01

... MANAGEMENT Federal Fleet Report § 102-34.345 What records do we need to keep? You are responsible for... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false What records do we need to keep? 102-34.345 Section 102-34.345 Public Contracts and Property Management Federal Property...

The yeast complex I equivalent NADH dehydrogenase rescues pink1 mutants.

Directory of Open Access Journals (Sweden)

Sven Vilain

2012-01-01

Full Text Available Pink1 is a mitochondrial kinase involved in Parkinson's disease, and loss of Pink1 function affects mitochondrial morphology via a pathway involving Parkin and components of the mitochondrial remodeling machinery. Pink1 loss also affects the enzymatic activity of isolated Complex I of the electron transport chain (ETC; however, the primary defect in pink1 mutants is unclear. We tested the hypothesis that ETC deficiency is upstream of other pink1-associated phenotypes. We expressed Saccaromyces cerevisiae Ndi1p, an enzyme that bypasses ETC Complex I, or sea squirt Ciona intestinalis AOX, an enzyme that bypasses ETC Complex III and IV, in pink1 mutant Drosophila and find that expression of Ndi1p, but not of AOX, rescues pink1-associated defects. Likewise, loss of function of subunits that encode for Complex I-associated proteins displays many of the pink1-associated phenotypes, and these defects are rescued by Ndi1p expression. Conversely, expression of Ndi1p fails to rescue any of the parkin mutant phenotypes. Additionally, unlike pink1 mutants, fly parkin mutants do not show reduced enzymatic activity of Complex I, indicating that Ndi1p acts downstream or parallel to Pink1, but upstream or independent of Parkin. Furthermore, while increasing mitochondrial fission or decreasing mitochondrial fusion rescues mitochondrial morphological defects in pink1 mutants, these manipulations fail to significantly rescue the reduced enzymatic activity of Complex I, indicating that functional defects observed at the level of Complex I enzymatic activity in pink1 mutant mitochondria do not arise from morphological defects. Our data indicate a central role for Complex I dysfunction in pink1-associated defects, and our genetic analyses with heterologous ETC enzymes suggest that Ndi1p-dependent NADH dehydrogenase activity largely acts downstream of, or in parallel to, Pink1 but upstream of Parkin and mitochondrial remodeling.

Effect of irradiation on fresh-keeping of strawberry stored at room temperature

International Nuclear Information System (INIS)

Zhao Yongfu; Xie Zongchuan; Lu Zhaoxin

1999-01-01

The fresh keeping period of strawberry irradiated with 4.0 kGy dose and stored at room temperature was prolonged to 6 days. Further experiment showed that the irradiation treatment decreased the number of mold in strawberry by two orders of magnitude, inhibited the strawberry fruit respiration and water loss, therefore, improved the effect of strawberry fresh-keeping

At-risk elementary school children with one year of classroom music instruction are better at keeping a beat.

Science.gov (United States)

Slater, Jessica; Tierney, Adam; Kraus, Nina

2013-01-01

Temporal processing underlies both music and language skills. There is increasing evidence that rhythm abilities track with reading performance and that language disorders such as dyslexia are associated with poor rhythm abilities. However, little is known about how basic time-keeping skills can be shaped by musical training, particularly during critical literacy development years. This study was carried out in collaboration with Harmony Project, a non-profit organization providing free music education to children in the gang reduction zones of Los Angeles. Our findings reveal that elementary school children with just one year of classroom music instruction perform more accurately in a basic finger-tapping task than their untrained peers, providing important evidence that fundamental time-keeping skills may be strengthened by short-term music training. This sets the stage for further examination of how music programs may be used to support the development of basic skills underlying learning and literacy, particularly in at-risk populations which may benefit the most.

Keeping it complicated: Mitochondrial genome plasticity across diplonemids.

Science.gov (United States)

Valach, Matus; Moreira, Sandrine; Hoffmann, Steve; Stadler, Peter F; Burger, Gertraud

2017-10-26

Chromosome rearrangements are important drivers in genome and gene evolution, with implications ranging from speciation to development to disease. In the flagellate Diplonema papillatum (Euglenozoa), mitochondrial genome rearrangements have resulted in nearly hundred chromosomes and a systematic dispersal of gene fragments across the multipartite genome. Maturation into functional RNAs involves separate transcription of gene pieces, joining of precursor RNAs via trans-splicing, and RNA editing by substitution and uridine additions both reconstituting crucial coding sequence. How widespread these unusual features are across diplonemids is unclear. We have analyzed the mitochondrial genomes and transcriptomes of four species from the Diplonema/Rhynchopus clade, revealing a considerable genomic plasticity. Although gene breakpoints, and thus the total number of gene pieces (~80), are essentially conserved across this group, the number of distinct chromosomes varies by a factor of two, with certain chromosomes combining up to eight unrelated gene fragments. Several internal protein-coding gene pieces overlap substantially, resulting, for example, in a stretch of 22 identical amino acids in cytochrome c oxidase subunit 1 and NADH dehydrogenase subunit 5. Finally, the variation of post-transcriptional editing patterns across diplonemids indicates compensation of two adverse trends: rapid sequence evolution and loss of genetic information through unequal chromosome segregation.

East–West GEO Satellite Station-Keeping with Degraded Thruster Response

Directory of Open Access Journals (Sweden)

Stoian Borissov

2015-09-01

Full Text Available The higher harmonic terms of Earth’s gravitational potential slowly modify the nominal longitude of geostationary Earth orbit (GEO satellites, while the third-body presence (Moon and Sun mainly affects their latitude. For this reason, GEO satellites periodically need to perform station-keeping maneuvers, namely, east–west and north–south maneuvers to compensate for longitudinal and latitudinal variations, respectively. During the operational lifetime of GEO satellites, the thrusters’ response when commanded to perform these maneuvers slowly departs from the original nominal impulsive behavior. This paper addresses the practical problem of how to perform reliable east–west station-keeping maneuvers when thruster response is degraded. The need for contingency intervention from ground-based satellite operators is reduced by breaking apart the scheduled automatic station-keeping maneuvers into smaller maneuvers. Orbital alignment and attitude are tracked on-board during and in between sub-maneuvers, and any off nominal variations are corrected for with subsequent maneuvers. These corrections are particularly important near the end of the lifetime of GEO satellites, where thruster response is farthest from nominal performance.

Hydroquinone analog 4-[(Tetrahydro-2H-pyran-2‑yl) oxy] phenol induces C26 colon cancer cell apoptosis and inhibits tumor growth in vivo.

Science.gov (United States)

Du, Qigen; Xin, Guang; Niu, Hai; Huang, Wen

2015-06-01

The 4[(Tetrahydro‑2H‑pyran‑2‑yl) oxy] phenol (XG‑d) hydroquinone analog, is found in Vaccinium vitis‑idaea  L. Although it is known for its antioxidant properties and high level of safety, its antitumor activity remains to be elucidated. In the present study, the anticancer effect of XG‑d was determined in vitro and in vivo. The cytotoxicity of XG‑d against C26 murine colon carcinoma cells was found to occur in a time‑ and concentration‑dependent manner, whereas little effect was observed in the two normal cell lines (HK‑2 and L02) investigated. Oral administration of XG‑d (100 mg/kg) had effects on the tumor growth of tumor‑bearing mice. Furthermore, marked apoptosis was observed using Hoechst 33258 staining and flow cytometric analysis with annexin V/propidium iodide double staining. XG‑d also downregulated the expression of B‑cell lymphoma 2 (Bcl‑2), increased the expression levels of Bcl‑2‑associated X protein and activated caspase‑9, caspase‑3 and poly(adenosine diphosphate‑ribose) polymerase. The present study demonstrated for the first time, to the best of our knowledge, that XG‑d inhibited cancer cell growth via the induction of apoptosis and was also able to inhibit tumor growth in vivo. These results demonstrated that XG‑d may be used as a potential natural agent for cancer therapy with low toxicity.

Keep Food, Water, and Medications Safe PSA (:60)

Centers for Disease Control (CDC) Podcasts

2017-10-25

This 60 second public service announcement is about the need to keep food, water and medications safe after a disaster.  Created: 10/25/2017 by Centers for Disease Control and Prevention (CDC).   Date Released: 10/25/2017.

Capsaicin Inhibits Multiple Bladder Cancer Cell Phenotypes by Inhibiting Tumor-Associated NADH Oxidase (tNOX and Sirtuin1 (SIRT1

Directory of Open Access Journals (Sweden)

Ming-Hung Lin

2016-06-01

Full Text Available Bladder cancer is one of the most frequent cancers among males, and its poor survival rate reflects problems with aggressiveness and chemo-resistance. Recent interest has focused on the use of chemopreventatives (nontoxic natural agents that may suppress cancer progression to induce targeted apoptosis for cancer therapy. Capsaicin, which has anti-cancer properties, is one such agent. It is known to preferentially inhibit a tumor-associated NADH oxidase (tNOX that is preferentially expressed in cancer/transformed cells. Here, we set out to elucidate the correlation between tNOX expression and the inhibitory effects of capsaicin in human bladder cancer cells. We showed that capsaicin downregulates tNOX expression and decreases bladder cancer cell growth by enhancing apoptosis. Moreover, capsaicin was found to reduce the expression levels of several proteins involved in cell cycle progression, in association with increases in the cell doubling time and enhanced cell cycle arrest. Capsaicin was also shown to inhibit the activation of ERK, thereby reducing the phosphorylation of paxillin and FAK, which leads to decreased cell migration. Finally, our results indicate that RNA interference-mediated tNOX depletion enhances spontaneous apoptosis, prolongs cell cycle progression, and reduces cell migration and the epithelial-mesenchymal transition. We also observed a downregulation of sirtuin 1 (SIRT1 in these tNOX-knockdown cells, a deacetylase that is important in multiple cellular functions. Taken together, our results indicate that capsaicin inhibits the growth of bladder cancer cells by inhibiting tNOX and SIRT1 and thereby reducing proliferation, attenuating migration, and prolonging cell cycle progression.

40 CFR 141.571 - What records does subpart T require my system to keep?

Science.gov (United States)

2010-07-01

... records does subpart T require my system to keep? Your system must keep several types of records based on... Benchmarking(§§ 141.540-141.544) Benchmark (including raw data and analysis) Indefinitely. ...

Developmental Neurotoxic Effects of Percutaneous Drug Delivery: Behavior and Neurochemical Studies in C57BL/6 Mice.

Directory of Open Access Journals (Sweden)

Huali Wu

Full Text Available Dermatosis often as a chronic disease requires effective long-term treatment; a comprehensive evaluation of mental health of dermatology drug does not receive enough attention. An interaction between dermatology and psychiatry has been increasingly described. Substantial evidence has accumulated that psychological stress can be associated with pigmentation, endocrine and immune systems in skin to create the optimal responses against pathogens and other physicochemical stressors to maintain or restore internal homeostasis. Additionally, given the common ectodermal origin shared by the brain and skin, we are interested in assessing how disruption of skin systems (pigmentary, endocrine and immune systems may play a key role in brain functions. Thus, we selected three drugs (hydroquinone, isotretinoin, tacrolimus with percutaneous excessive delivery to respectively intervene in these systems and then evaluate the potential neurotoxic effects. Firstly, C57BL/6 mice were administrated a dermal dose of hydroquinone cream, isotretinoin gel or tacrolimus ointment (2%, 0.05%, 0.1%, respectively, 5 times of the clinical dose. Behavioral testing was performed and levels of proteins were measured in the hippocampus. It was found that mice treated with isotretinoin or tacrolimus, presented a lower activity in open-field test and obvious depressive-like behavior in tail suspension test. Besides, they damaged cytoarchitecture, reduced the level of 5-HT-5-HT1A/1B system and increased the expression of apoptosis-related proteins in the hippocampus. To enable sensitive monitoring the dose-response characteristics of the consecutive neurobehavioral disorders, mice received gradient concentrations of hydroquinone (2%, 4%, 6%. Subsequently, hydroquinone induced behavioral disorders and hippocampal dysfunction in a dose-dependent response. When doses were high as 6% which was 3 times higher than 2% dose, then 100% of mice exhibited depressive-like behavior. Certainly

Metabolic engineering of an ATP-neutral Embden-Meyerhof-Parnas pathway in Corynebacterium glutamicum: growth restoration by an adaptive point mutation in NADH dehydrogenase.

Science.gov (United States)

Komati Reddy, Gajendar; Lindner, Steffen N; Wendisch, Volker F

2015-03-01

Corynebacterium glutamicum uses the Embden-Meyerhof-Parnas pathway of glycolysis and gains 2 mol of ATP per mol of glucose by substrate-level phosphorylation (SLP). To engineer glycolysis without net ATP formation by SLP, endogenous phosphorylating NAD-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was replaced by nonphosphorylating NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (GapN) from Clostridium acetobutylicum, which irreversibly converts glyceraldehyde-3-phosphate (GAP) to 3-phosphoglycerate (3-PG) without generating ATP. As shown recently (S. Takeno, R. Murata, R. Kobayashi, S. Mitsuhashi, and M. Ikeda, Appl Environ Microbiol 76:7154-7160, 2010, http://dx.doi.org/10.1128/AEM.01464-10), this ATP-neutral, NADPH-generating glycolytic pathway did not allow for the growth of Corynebacterium glutamicum with glucose as the sole carbon source unless hitherto unknown suppressor mutations occurred; however, these mutations were not disclosed. In the present study, a suppressor mutation was identified, and it was shown that heterologous expression of udhA encoding soluble transhydrogenase from Escherichia coli partly restored growth, suggesting that growth was inhibited by NADPH accumulation. Moreover, genome sequence analysis of second-site suppressor mutants that were able to grow faster with glucose revealed a single point mutation in the gene of non-proton-pumping NADH:ubiquinone oxidoreductase (NDH-II) leading to the amino acid change D213G, which was shared by these suppressor mutants. Since related NDH-II enzymes accepting NADPH as the substrate possess asparagine or glutamine residues at this position, D213G, D213N, and D213Q variants of C. glutamicum NDH-II were constructed and were shown to oxidize NADPH in addition to NADH. Taking these findings together, ATP-neutral glycolysis by the replacement of endogenous NAD-dependent GAPDH with NADP-dependent GapN became possible via oxidation of NADPH formed in this pathway by mutant NADPH

The company you keep: spreading effects of financial fraud on investor trust.

Science.gov (United States)

Bernet, Patrick Michael; Getzen, Thomas E

2007-01-01

Investor trust is valuable to health care organizations. Without it, they may face higher capital costs. This study explores recent cases of fraud and the appearance of impropriety by health care organizations, focusing on the manners in which trust was violated, the systems that allowed those violations, and the effects on financial markets. Increases in the incidence and scale of such transgressions may be harbingers of worse times ahead. This article examines how recent events have affected the cost of capital, and what health care organizations can do to avoid being judged by the company they keep.

Keep up or drown: adjustment of western Pacific coral reefs to sea-level rise in the 21st century.

Science.gov (United States)

van Woesik, R; Golbuu, Y; Roff, G

2015-07-01

Since the Mid-Holocene, some 5000 years ago, coral reefs in the Pacific Ocean have been vertically constrained by sea level. Contemporary sea-level rise is releasing these constraints, providing accommodation space for vertical reef expansion. Here, we show that Porites microatolls, from reef-flat environments in Palau (western Pacific Ocean), are 'keeping up' with contemporary sea-level rise. Measurements of 570 reef-flat Porites microatolls at 10 locations around Palau revealed recent vertical skeletal extension (78±13 mm) over the last 6-8 years, which is consistent with the timing of the recent increase in sea level. We modelled whether microatoll growth rates will potentially 'keep up' with predicted sea-level rise in the near future, based upon average growth, and assuming a decline in growth for every 1°C increase in temperature. We then compared these estimated extension rates with rates of sea-level rise under four Representative Concentration Pathways (RCPs). Our model suggests that under low-mid RCP scenarios, reef-coral growth will keep up with sea-level rise, but if greenhouse gas concentrations exceed 670 ppm atmospheric CO2 levels and with +2.2°C sea-surface temperature by 2100 (RCP 6.0 W m(-2)), our predictions indicate that Porites microatolls will be unable to keep up with projected rates of sea-level rise in the twenty-first century.

Prenatal dog-keeping practices vary by race: speculations on implications for disparities in childhood health and disease.

Science.gov (United States)

Ezell, Jerel M; Cassidy-Bushrow, Andrea E; Havstad, Suzanne; Joseph, Christine L M; Wegienka, Ganesa; Jones, Kyra; Ownby, Dennis R; Johnson, Christine Cole

2014-01-01

There is consistent evidence demonstrating that pet-keeping, particularly of dogs, is beneficial to human health. We explored relationships between maternal race and prenatal dog-keeping, accounting for measures of socioeconomic status that could affect the choice of owning a pet, in a demographically diverse, unselected birth cohort. Self-reported data on mothers' race, socioeconomic characteristics and dog-keeping practices were obtained during prenatal interviews and analyzed cross-sectionally. Robust methods of covariate balancing via propensity score analysis were utilized to examine if race (Black vs White), independent of other participant traits, influenced prenatal dog-keeping. A birth cohort study conducted in a health care system in metropolitan Detroit, Michigan between September 2003 and November 2007. 1065 pregnant women (n=775 or 72.8% Black), between ages 21 and 45, receiving prenatal care. Participant's self-report of race/ethnicity and prenatal dog-keeping, which was defined as her owning or caring for > or =1 dog for more than 1 week at her home since learning of her pregnancy, regardless of whether the dog was kept inside or outside of her home. In total, 294 women (27.6%) reported prenatal dog-keeping. Prenatal dog-keeping was significantly lower among Black women as compared to White women (20.9% vs 45.5%, Pdog-keeping not fully explained by measures of socioeconomic status. Racial differences in prenatal dog-keeping may contribute to childhood health disparities.

Pretest and Posttest Results of the First KEEP Program Year. Technical Report #5.

Science.gov (United States)

Gallimore, Ronald; And Others

This report presents a pre- and posttest evaluation of the first program year of the Kamehameha Early Education Program (KEEP). Each of the 28 children in the KEEP kindergarten class received three tests: the Wechsler Preschool and Primary Scale of Intelligence (WPPSI), the Metropolitan Readiness Test (MRT), and the Standard English Repetition…

Humanoid Robotics: Real-Time Object Oriented Programming

Science.gov (United States)

Newton, Jason E.

2005-01-01

Programming of robots in today's world is often done in a procedural oriented fashion, where object oriented programming is not incorporated. In order to keep a robust architecture allowing for easy expansion of capabilities and a truly modular design, object oriented programming is required. However, concepts in object oriented programming are not typically applied to a real time environment. The Fujitsu HOAP-2 is the test bed for the development of a humanoid robot framework abstracting control of the robot into simple logical commands in a real time robotic system while allowing full access to all sensory data. In addition to interfacing between the motor and sensory systems, this paper discusses the software which operates multiple independently developed control systems simultaneously and the safety measures which keep the humanoid from damaging itself and its environment while running these systems. The use of this software decreases development time and costs and allows changes to be made while keeping results safe and predictable.

Keeping Track of Your Blood Sugar (For Kids)

Science.gov (United States)

... diabetes care plan. The more information you, your parents, and your diabetes health care team have, the easier it is to keep your blood sugar levels under control. And when they're under control, diabetes isn't controlling you — you're controlling it! Reviewed by: Steven ...

You Can Help Keep the Air Cleaner -- Every Day

Science.gov (United States)

... car and avoid extended idling. Be sure your tires are properly inflated. Keep car, boat and other ... little higher in the summer and lower in winter. Participate in local energy conservation programs. Look for ...

Effects of the deletion of the Escherichia coli frataxin homologue CyaY on the respiratory NADH:ubiquinone oxidoreductase

Directory of Open Access Journals (Sweden)

Grauman Peter L

2007-07-01

Full Text Available Abstract Background Frataxin is discussed as involved in the biogenesis of iron-sulfur clusters. Recently it was discovered that a frataxin homologue is a structural component of the respiratory NADH:ubiquinone oxidoreductase (complex I in Thermus thermophilus. It was not clear whether frataxin is in general a component of complex I from bacteria. The Escherichia coli homologue of frataxin is coined CyaY. Results We report that complex I is completely assembled to a stable and active enzyme complex equipped with all known iron-sulfur clusters in a cyaY mutant of E. coli. However, the amount of complex I is reduced by one third compared to the parental strain. Western blot analysis and live cell imaging of CyaY engineered with a GFP demonstrated that CyaY is located in the cytoplasm and not attached to the membrane as to be expected if it were a component of complex I. Conclusion CyaY plays a non-essential role in the assembly of complex I in E. coli. It is not a structural component but may transiently interact with the complex.

Future of keeping pet reptiles and amphibians: towards integrating animal welfare, human health and environmental sustainability.

Science.gov (United States)

Pasmans, Frank; Bogaerts, Serge; Braeckman, Johan; Cunningham, Andrew A; Hellebuyck, Tom; Griffiths, Richard A; Sparreboom, Max; Schmidt, Benedikt R; Martel, An

2017-10-28

The keeping of exotic pets is currently under debate and governments of several countries are increasingly exploring the regulation, or even the banning, of exotic pet keeping. Major concerns are issues of public health and safety, animal welfare and biodiversity conservation. The keeping of reptiles and amphibians in captivity encompasses all the potential issues identified with keeping exotic pets, and many of those relating to traditional domestic pets. Within the context of risks posed by pets in general, the authors argue for the responsible and sustainable keeping of reptile and amphibian pets by private persons, based on scientific evidence and on the authors' own expertise (veterinary medicine, captive husbandry, conservation biology). © British Veterinary Association (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Gate-Keeping and Feedback as Determinants of the Translation ...

African Journals Online (AJOL)

Mrs Afam

Based on a theoretical perspective and a critical documentary analysis, this paper ... view since the message (the context, meaning) is first encoded (given form) in ... (feedback and gate keeping) greatly determine the communication process ...

Struggling to Hear? Tiny Devices Can Keep You Connected

Science.gov (United States)

... Human Services Search form Search Site Menu Home Latest Issue Past Issues Special Issues Subscribe May 2018 Print this issue Struggling to Hear? Tiny Devices Can Keep You Connected En español Send us ...

Convexification of the Range-Only Station Keeping Problem

NARCIS (Netherlands)

Cao, M.; Morse, A.S.

2008-01-01

Using concepts from switched adaptive control theory plus a special parameterization of the class of 2 x 2 nonsingular matrices, a tractable and provably correct solution is given to the three landmark station keeping problem in the plane in which range measurements are the only sensed signals upon

25 CFR 12.41 - Who keeps statistics for Indian country law enforcement activities?

Science.gov (United States)

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Who keeps statistics for Indian country law enforcement activities? 12.41 Section 12.41 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAW AND ORDER INDIAN COUNTRY LAW ENFORCEMENT Records and Information § 12.41 Who keeps statistics for Indian country law enforcement activities? The Director...

Calcium signaling in brain mitochondria: interplay of malate aspartate NADH shuttle and calcium uniporter/mitochondrial dehydrogenase pathways.

Science.gov (United States)

Contreras, Laura; Satrústegui, Jorgina

2009-03-13

Ca2+ signaling in mitochondria has been mainly attributed to Ca2+ entry to the matrix through the Ca2+ uniporter and activation of mitochondrial matrix dehydrogenases. However, mitochondria can also sense increases in cytosolic Ca2+ through a mechanism that involves the aspartate-glutamate carriers, extramitochondrial Ca2+ activation of the NADH malate-aspartate shuttle (MAS). Both pathways are linked through the shared substrate alpha-ketoglutarate (alphaKG). Here we have studied the interplay between the two pathways under conditions of Ca2+ activation. We show that alphaKG becomes limiting when Ca2+ enters in brain or heart mitochondria, but not liver mitochondria, resulting in a drop in alphaKG efflux through the oxoglutarate carrier and in a drop in MAS activity. Inhibition of alphaKG efflux and MAS activity by matrix Ca2+ in brain mitochondria was fully reversible upon Ca2+ efflux. Because of their differences in cytosolic calcium concentration requirements, the MAS and Ca2+ uniporter-mitochondrial dehydrogenase pathways are probably sequentially activated during a Ca2+ transient, and the inhibition of MAS at the center of the transient may provide an explanation for part of the increase in lactate observed in the stimulated brain in vivo.

Virginia Tech dining keeps customer service fresh (with Relish!)

OpenAIRE

Chadwick, Heather Riley

2005-01-01

Virginia Tech is consistently ranked among the top universities in providing its students with the very best in dining options. One important way they make that happen is keeping in touch with student preferences and needs.

40 CFR 63.5430 - What records must I keep?

Science.gov (United States)

2010-07-01

... versions of the plan and make them readily available for inspection for at least 5 years after each... process operation. (g) If you use an emission control device, you must keep records of monitoring data as...

Power of Your Pancreas: Keep Your Digestive Juices Flowing

Science.gov (United States)

... 2017 Print this issue The Power of Your Pancreas Keep Your Digestive Juices Flowing En español Send ... in Check Better Check Your Bowels Wise Choices Pancreas Problems? Talk to your doctor if you have ...

Time and Space: The difference between following time headway and distance headway instructions

NARCIS (Netherlands)

Risto, Malte; Martens, Marieke Hendrikje

2013-01-01

In order to guarantee safety, drivers are advised to keep large enough headways. However, headway advice is often provided in terms of time headway, without knowing whether this is the right way of presenting the advice. According to a psychophysics theory, attaining a time headway would indeed

Time and space: The difference between following time headway and distance headway instructions

NARCIS (Netherlands)

Risto, M.; Martens, M.H.

2013-01-01

In order to guarantee safety, drivers are advised to keep large enough headways. However, headway advice is often provided in terms of time headway, without knowing whether this is the right way of presenting the advice. According to a psychophysics theory, attaining a time headway would indeed

The level of menadione redox-cycling in pancreatic β-cells is proportional to the glucose concentration: Role of NADH and consequences for insulin secretion

Energy Technology Data Exchange (ETDEWEB)

Heart, Emma [Cellular Dynamics Program, Marine Biological Laboratory, Woods Hole, MA, 02543 (United States); Palo, Meridith; Womack, Trayce [Department of Science, United States Coast Guard Academy, New London, CT, 06320 (United States); Smith, Peter J.S. [Cellular Dynamics Program, Marine Biological Laboratory, Woods Hole, MA, 02543 (United States); Institute for Life Sciences, University of Southampton (United Kingdom); Gray, Joshua P., E-mail: Joshua.p.gray@uscga.edu [Cellular Dynamics Program, Marine Biological Laboratory, Woods Hole, MA, 02543 (United States); Department of Science, United States Coast Guard Academy, New London, CT, 06320 (United States)

2012-01-15

Pancreatic β-cells release insulin in response to elevation of glucose from basal (4–7 mM) to stimulatory (8–16 mM) levels. Metabolism of glucose by the β-cell results in the production of low levels of reactive oxygen intermediates (ROI), such as hydrogen peroxide (H{sub 2}O{sub 2}), a newly recognized coupling factor linking glucose metabolism to insulin secretion. However, high and toxic levels of H{sub 2}O{sub 2} inhibit insulin secretion. Menadione, which produces H{sub 2}O{sub 2} via redox cycling mechanism in a dose-dependent manner, was investigated for its effect on β-cell metabolism and insulin secretion in INS-1 832/13, a rat β-cell insulinoma cell line, and primary rodent islets. Menadione-dependent redox cycling and resulting H{sub 2}O{sub 2} production under stimulatory glucose exceeded several-fold those reached at basal glucose. This was paralleled by a differential effect of menadione (0.1–10 μM) on insulin secretion, which was enhanced at basal, but inhibited at stimulatory glucose. Redox cycling of menadione and H{sub 2}O{sub 2} formation was dependent on glycolytically-derived NADH, as inhibition of glycolysis and application of non-glycogenic insulin secretagogues did not support redox cycling. In addition, activity of plasma membrane electron transport, a system dependent in part on glycolytically-derived NADH, was also inhibited by menadione. Menadione-dependent redox cycling was sensitive to the NQO1 inhibitor dicoumarol and the flavoprotein inhibitor diphenylene iodonium, suggesting a role for NQO1 and other oxidoreductases in this process. These data may explain the apparent dichotomy between the stimulatory and inhibitory effects of H{sub 2}O{sub 2} and menadione on insulin secretion. -- Highlights: ► Menadione stimulation or inhibition of insulin secretion is dependent upon applied glucose levels. ► Menadione-dependent H{sub 2}O{sub 2} production is proportional to applied glucose levels. ► Quinone-mediated redox cycling

The level of menadione redox-cycling in pancreatic β-cells is proportional to the glucose concentration: Role of NADH and consequences for insulin secretion

International Nuclear Information System (INIS)

Heart, Emma; Palo, Meridith; Womack, Trayce; Smith, Peter J.S.; Gray, Joshua P.

2012-01-01

Pancreatic β-cells release insulin in response to elevation of glucose from basal (4–7 mM) to stimulatory (8–16 mM) levels. Metabolism of glucose by the β-cell results in the production of low levels of reactive oxygen intermediates (ROI), such as hydrogen peroxide (H 2 O 2 ), a newly recognized coupling factor linking glucose metabolism to insulin secretion. However, high and toxic levels of H 2 O 2 inhibit insulin secretion. Menadione, which produces H 2 O 2 via redox cycling mechanism in a dose-dependent manner, was investigated for its effect on β-cell metabolism and insulin secretion in INS-1 832/13, a rat β-cell insulinoma cell line, and primary rodent islets. Menadione-dependent redox cycling and resulting H 2 O 2 production under stimulatory glucose exceeded several-fold those reached at basal glucose. This was paralleled by a differential effect of menadione (0.1–10 μM) on insulin secretion, which was enhanced at basal, but inhibited at stimulatory glucose. Redox cycling of menadione and H 2 O 2 formation was dependent on glycolytically-derived NADH, as inhibition of glycolysis and application of non-glycogenic insulin secretagogues did not support redox cycling. In addition, activity of plasma membrane electron transport, a system dependent in part on glycolytically-derived NADH, was also inhibited by menadione. Menadione-dependent redox cycling was sensitive to the NQO1 inhibitor dicoumarol and the flavoprotein inhibitor diphenylene iodonium, suggesting a role for NQO1 and other oxidoreductases in this process. These data may explain the apparent dichotomy between the stimulatory and inhibitory effects of H 2 O 2 and menadione on insulin secretion. -- Highlights: ► Menadione stimulation or inhibition of insulin secretion is dependent upon applied glucose levels. ► Menadione-dependent H 2 O 2 production is proportional to applied glucose levels. ► Quinone-mediated redox cycling is dependent on glycolysis

A Nordic survey of management practices and owners’ attitudes towards keeping horses in groups

DEFF Research Database (Denmark)

Hartmann, E.; Bøe, K.E.; Christensen, Janne Winther

2015-01-01

Keeping horses in groups is widely recommended but limited information is vailable about how this is implemented in practice. The aim of this survey was to describe how horses are kept in the Nordic countries in relation to sex, age, breed, and equestrian discipline and to assess owners’ attitudes...... widespread, such as it is the case for most farm animals, future research could focus on solving some of the reoccurring problems perceived with keeping horses in groups. The dissemination of evidence-based information on all aspects around keeping horses in groups can ultimately stimulate further positive...

Ultrasensitive and simultaneous detection of hydroquinone, catechol and resorcinol based on the electrochemical co-reduction prepared Au-Pd nanoflower/reduced graphene oxide nanocomposite

International Nuclear Information System (INIS)

Chen, Yuan; Liu, Xiaoying; Zhang, Si; Yang, Liuqing; Liu, Meiling; Zhang, Youyu; Yao, Shouzhuo

2017-01-01

A simple and efficient eletrochemical sensing platform for simultaneous detection of hydroquinone (HQ), catechol (CC) and resorcinol (RC) based on the Au-Pd bimetallic and graphene is described in this paper. The Au-Pd reduced graphene oxide (Au-Pd NF/rGO) was prepared by the electrochemical co-reduction deposition via cyclic voltammetry method (CV). The Au-Pd NF/rGO nanocomposite was examined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and electrochemical methods CV and differential pulse voltammety (DPV) study showed that the three dihydroxybenzene isomers can be catalytically oxidized and discriminated simultaneously on the Au-Pd NF/rGO/GCE. The presence of Pd makes the performance of the sensor superior to that of in the absence of it. Owing to the integrated superior conductivity and excellent catalytic property of Au-Pd NF/rGO, the sensitive and simultaneous detection of HQ, CC and RC was realized in the individual or triple-components solution based on the as proposed Au-Pd NF/rGO/GCE, which shows wide linear range and low detection limit. The detection of them in tap water, river water and lake water were also successfully performed and good recovery was obtained.

Belly Fat in Women: Taking --and Keeping-- It off

Science.gov (United States)

... nuts and certain vegetable oils — instead. Replace sugary beverages. Drink water or beverages with artificial sweetener instead. Keep portion sizes in ... steps per day to prevent weight gain. Some studies indicate it might take 15,000 steps per ...

Individual, household and community level factors associated with keeping tuberculosis status secret in Ghana

Directory of Open Access Journals (Sweden)

Joshua Amo-Adjei

2016-11-01

Full Text Available Abstract Background In tuberculosis (TB control, early disclosure is recommended for the purposes of treatment as well as a means of reducing or preventing person-to-person transmission of the bacteria. However, disclosure maybe avoided as a means of escaping stigma, and possible discrimination. This study aimed at providing insights into factors associated with intentions of Ghanaians to keep positive TB diagnosis in their families’ a secret. Methods The paper was based on data from the 2014 Ghana Demographic and Health Survey. Descriptive statistics of proportions with Chi-square test and binary logistic regression were used to identify individual, household and community level factors that predicted the outcome variable (keeping TB secret. Results Women were more inclined (33% than men (25% to keep TB in the family a secret. Views about keeping TB secret declined with age for both sexes. For women, higher education had a positive association with whether TB in the family would be kept a secret or not but the same was not observed for men. In a multivariable regression model, the strongest predictor of keeping TB secret was whether the respondent would keep HIV secret, and this was uniform among women (OR = 6.992, p < 0.001 and men (OR = 9.870, p < 0.001. Conclusion Unwillingness towards disclosing TB status in Ghana is associated with varied socioeconomic and demographic characteristics, which may be driven by fears of stigma and discrimination. Addressing TB-related stigma and discrimination can enhance positive attitudes towards TB disclosure. For an infectious disease such as TB, openness towards status disclosure is important for public health.

Oilpatch Infobahn: SCADANet keeps gas marketers up to speed

Energy Technology Data Exchange (ETDEWEB)

Leschart, M.

2002-08-01

A new SCADAnet product that keeps tabs on the performance of natural gas wells in real time is described. The system consists of two subgroups. In one subgroup the system acts as a SCADA host for groups of wells, via the field connection, that communicate directly to the SCADAnet server through a dedicated remote terminal. In the second subgroup an augmented PC at the plant concentrates data from a number of SCADA hosts and plant-distributed control systems. One of the system's key selling points is the ability to provide real-time data to marketers, who up-to-now had to rely on old (up to a month) figures when estimating the amount of sales gas a producing company has available. The software not only allows incorporation of field data directly into its production accounting system, but also has an alarm feature notifying the operator or marketer of a production problem at a specific well via e-mail, pager or voice mail. Since the developers of the system had remote plant sites in mind when developing the system, SCADAnet contains few display-stalling, high resolution graphic images. It is designed for 19.2 bytes/sec modem in mind, so that even with a relatively slow Internet connection producers can access real-time production data and analyze the information with the software's trending features.

Oilpatch Infobahn: SCADANet keeps gas marketers up to speed

International Nuclear Information System (INIS)

Leschart, M.

2002-01-01

A new SCADAnet product that keeps tabs on the performance of natural gas wells in real time is described. The system consists of two subgroups. In one subgroup the system acts as a SCADA host for groups of wells, via the field connection, that communicate directly to the SCADAnet server through a dedicated remote terminal. In the second subgroup an augmented PC at the plant concentrates data from a number of SCADA hosts and plant-distributed control systems. One of the system's key selling points is the ability to provide real-time data to marketers, who up-to-now had to rely on old (up to a month) figures when estimating the amount of sales gas a producing company has available. The software not only allows incorporation of field data directly into its production accounting system, but also has an alarm feature notifying the operator or marketer of a production problem at a specific well via e-mail, pager or voice mail. Since the developers of the system had remote plant sites in mind when developing the system, SCADAnet contains few display-stalling, high resolution graphic images. It is designed for 19.2 bytes/sec modem in mind, so that even with a relatively slow Internet connection producers can access real-time production data and analyze the information with the software's trending features

Strategies to Keep the MS 1 and MS 2 Subjects Relevant and Learner-Centered With Selected Courses in Bicol University

Directory of Open Access Journals (Sweden)

Mercielen R. De Leon

2014-10-01

Full Text Available CHED Memorandum Order 59 series of 1996 mandates the teaching of Philippine History and Rizal to students in the tertiary level as part of the General Education Curriculum. Bicol University lodges upon the General Education Department (GenEd the teaching of the Mandated Subjects. The General Education Department, therefore, faces the challenge of fostering the values of nationalism and cultural heritage, and at the same time, keeping up with the demands of time for global competitiveness, relevance of the subject to economic and social developments, and keeping up with the learner-centered curriculum. Five courses with different interests and specializations (Computer Science, Education, Biology, Philosophy, Physical Education during the school year of 2011- 2012 were subjected to surveys, observation, rubrics and evaluation. This resulted to varied teaching strategies, activities and required output for every course which catered to their distinct interests, skills, and aligned with the required skills of their fields of specialization

78 FR 65038 - Reports, Forms, and Record Keeping Requirements

Science.gov (United States)

2013-10-30

... DEPARTMENT OF TRANSPORTATION National Highway Traffic Safety Administration [U.S. DOT Docket No. NHTSA-2013-0113] Reports, Forms, and Record Keeping Requirements AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT. ACTION: Request for public comment on proposed collection of information. SUMMARY...

75 FR 50034 - Reports, Forms, and Record Keeping Requirements

Science.gov (United States)

2010-08-16

... DEPARTMENT OF TRANSPORTATION National Highway Traffic Safety Administration [U.S. DOT Docket No. NHTSA-2010-0109] Reports, Forms, and Record Keeping Requirements AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT. ACTION: Request for public comment on proposed collection of information. SUMMARY...

Mitochondrial nicotinamide adenine dinucleotide reduced (NADH) oxidation links the tricarboxylic acid (TCA) cycle with methionine metabolism and nuclear DNA methylation.

Science.gov (United States)

Lozoya, Oswaldo A; Martinez-Reyes, Inmaculada; Wang, Tianyuan; Grenet, Dagoberto; Bushel, Pierre; Li, Jianying; Chandel, Navdeep; Woychik, Richard P; Santos, Janine H

2018-04-18

Mitochondrial function affects many aspects of cellular physiology, and, most recently, its role in epigenetics has been reported. Mechanistically, how mitochondrial function alters DNA methylation patterns in the nucleus remains ill defined. Using a cell culture model of induced mitochondrial DNA (mtDNA) depletion, in this study we show that progressive mitochondrial dysfunction leads to an early transcriptional and metabolic program centered on the metabolism of various amino acids, including those involved in the methionine cycle. We find that this program also increases DNA methylation, which occurs primarily in the genes that are differentially expressed. Maintenance of mitochondrial nicotinamide adenine dinucleotide reduced (NADH) oxidation in the context of mtDNA loss rescues methionine salvage and polyamine synthesis and prevents changes in DNA methylation and gene expression but does not affect serine/folate metabolism or transsulfuration. This work provides a novel mechanistic link between mitochondrial function and epigenetic regulation of gene expression that involves polyamine and methionine metabolism responding to changes in the tricarboxylic acid (TCA) cycle. Given the implications of these findings, future studies across different physiological contexts and in vivo are warranted.

Rhodium-Coordinated Poly(arylene-ethynylene)-alt-Poly(arylene-vinylene) Copolymer Acting as Photocatalyst for Visible-Light-Powered NAD+/NADH Reduction

Science.gov (United States)

2014-01-01

A 2,2′-bipyridyl-containing poly(arylene-ethynylene)-alt-poly(arylene-vinylene) polymer, acting as a light-harvesting ligand system, was synthesized and coupled to an organometallic rhodium complex designed for photocatalytic NAD+/NADH reduction. The material, which absorbs over a wide spectral range, was characterized by using various analytical techniques, confirming its chemical structure and properties. The dielectric function of the material was determined from spectroscopic ellipsometry measurements. Photocatalytic reduction of nucleotide redox cofactors under visible light irradiation (390–650 nm) was performed and is discussed in detail. The new metal-containing polymer can be used to cover large surface areas (e.g. glass beads) and, due to this immobilization step, can be easily separated from the reaction solution after photolysis. Because of its high stability, the polymer-based catalyst system can be repeatedly used under different reaction conditions for (photo)chemical reduction of NAD+. With this concept, enzymatic, photo-biocatalytic systems for solar energy conversion can be facilitated, and the precious metal catalyst can be recycled. PMID:25130570

An amperometric enzyme biosensor for real-time measurements of cellobiohydrolase activity on insoluble cellulose

DEFF Research Database (Denmark)

Cruys-Bagger, Nicolaj; Guilin, Ren; Tatsumi, Hirosuke

2012-01-01

An amperometric enzyme biosensor for continuous detection of cellobiose has been implemented as an enzyme assay for cellulases. We show that the initial kinetics for cellobiohydrolase I, Cel7A from Trichoderma reesei, acting on different types of cellulose substrates, semi-crystalline and amorphous......, can be monitored directly and in real-time by an enzyme-modified electrode based on cellobiose dehydrogenase (CDH) from Phanerochaete chrysosporium (Pc). PcCDH was cross-linked and immobilized on the surface of a carbon paste electrode which contained a mediator, benzoquinone. An oxidation current...... of the reduced mediator, hydroquinone, produced by the CDH-catalyzed reaction with cellobiose, was recorded under constant-potential amperometry at +0.5 V (vs. Ag/AgCl). The CDH-biosensors showed high sensitivity (87.7 µA mM−1 cm−2), low detection limit (25 nM), and fast response time (t95% ∼ 3 s...

76 FR 30423 - Reports, Forms, and Record keeping Requirements

Science.gov (United States)

2011-05-25

... DEPARTMENT OF TRANSPORTATION National Highway Traffic Safety Administration Reports, Forms, and Record keeping Requirements AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT. ACTION: Notice. SUMMARY: In compliance with the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.), this...

Any time, anywhere : communications system keeps employees connected

Energy Technology Data Exchange (ETDEWEB)

Louie, J.

2007-07-15

Cisco Systems Canada is a leading computer networking company that has developed a business solution for the oil and gas sector that allows employees to communicate more effectively. Cisco Unified Communications provides a set of applications or services that can ride on top an existing data network. The network allows telephone conferencing through a centrally located internal application, saving companies the cost of using a conferencing service. Cisco Unified Meeting place allows workers at different locations to discuss, review and edit documents in real time. Other applications can be added and made available to everyone. Pengrowth Energy Trust, which implemented the Cisco system a few years ago, claims it is much faster and more convenient than the previous system. Pengrowth has benefited from the its tie-in with e-mail server Microsoft Exchange. Users can listen to voice mails on their computers and also have the option of listening to their e-mails when they call into the office. The system provides a very well tracked record and also allows four-digit dialing throughout most of the company's multiple locations, thereby eliminating costly long distance charges. Pengrowth is now considering implementing other new products from Cisco, such as the Unified Mobility Manager which links cell phones and desk phones. It was concluded that Cisco systems offer the advantages of flexibility, mobility and cost reduction. 1 fig.

Keeping Up-to-Date

Directory of Open Access Journals (Sweden)

Norman L Jones

2000-01-01

Full Text Available As a senior (read older practising respirologist, I have come to appreciate my position as editor, which keeps me current with present practice standards. Everyone talks about the volume and flow of new knowledge, and not a week goes by in which I feel that I know enough to treat my patients optimally. This is particularly the case when it comes to antibiotic usage: the number of antibiotics and the confident way that junior colleagues bandy them about leaves me distinctly depressed because most of the names mean little to me; even the families and generations of antibiotics seem beyond my grasp. That is why I welcomed the request from Dr Lionel Mandell to publish a summary statement on the use of antibiotics in community-acquired pneumonia (CAP, which appears on pages 371-382 of the current issue of the Canadian Respiratory Journal.

Drought Tip: Keeping Plants Alive under Drought or Water Restrictions

OpenAIRE

Hartin, Janet; Oki, Loren; Fujino, Dave; Faber, Ben

2015-01-01

Plants that don't receive enough water eventually show signs of water stress. During a drought or under water restrictions aimed at water conservation, keeping plants alive can be particularly difficult.

Preclinical evidence of mitochondrial nicotinamide adenine dinucleotide as an effective alarm parameter under hypoxia

Science.gov (United States)

Shi, Hua; Sun, Nannan; Mayevsky, Avraham; Zhang, Zhihong; Luo, Qingming

2014-01-01

Early detection of tissue hypoxia in the intensive care unit is essential for effective treatment. Reduced nicotinamide adenine dinucleotide (NADH) has been suggested to be the most sensitive indicator of tissue oxygenation at the mitochondrial level. However, no experimental evidence comparing the kinetics of changes in NADH and other physiological parameters has been provided. The aim of this study is to obtain the missing data in a systematic and reliable manner. We constructed four acute hypoxia models, including hypoxic hypoxia, hypemic hypoxia, circulatory hypoxia, and histogenous hypoxia, and measured NADH fluorescence, tissue reflectance, cerebral blood flow, respiration, and electrocardiography simultaneously from the induction of hypoxia until death. We found that NADH was not always the first onset parameter responding to hypoxia. The order of responses was mainly affected by the cause of hypoxia. However, NADH reached its alarm level earlier than the other monitored parameters, ranging from several seconds to >10 min. As such, we suggest that the NADH can be used as a hypoxia indicator, although the exact level that should be used must be further investigated. When the NADH alarm is detected, the body still has a chance to recover if appropriate and timely treatment is provided.

Shallow Water Station Keeping of AUVs Using Multi-Sensor Fusion for Wave Disturbance Prediction and Compensation

National Research Council Canada - National Science Library

Riedel, Jeffrey S; Healey, Anthony J

2005-01-01

An important capability for Autonomous Underwater Vehicles (AUVs) is station keeping. Station keeping is the ability of a vehicle to maintain position and orientation with regard to a reference object...

78 FR 73237 - Reports, Forms and Record Keeping Requirements Agency Information Collection Activity Under OMB...

Science.gov (United States)

2013-12-05

...-0088] Reports, Forms and Record Keeping Requirements Agency Information Collection Activity Under OMB... entities over which the agency exercises regulatory authority. Recent trends lead the agency to estimate.... Requesters are not required to keep copies of any records or reports [[Page 73238

Clinical audit teaching in record-keeping for dental undergraduates at International Medical University, Kuala Lumpur, Malaysia.

Science.gov (United States)

Chong, Jun A; Chew, Jamie K Y; Ravindranath, Sneha; Pau, Allan

2014-02-01

This study investigated the impact of clinical audit training on record-keeping behavior of dental students and students' perceptions of the clinical audit training. The training was delivered to Year 4 and Year 5 undergraduates at the School of Dentistry, International Medical University, Kuala Lumpur, Malaysia. It included a practical audit exercise on patient records. The results were presented by the undergraduates, and guidelines were framed from the recommendations proposed. Following this, an audit of Year 4 and Year 5 students' patient records before and after the audit training was carried out. A total of 100 records were audited against a predetermined set of criteria by two examiners. An email survey of the students was also conducted to explore their views of the audit training. Results showed statistically significant improvements in record-keeping following audit training. Responses to the email survey were analyzed qualitatively. Respondents reported that the audit training helped them to identify deficiencies in their record-keeping practice, increased their knowledge in record-keeping, and improved their record-keeping skills. Improvements in clinical audit teaching were also proposed.

Good Thoughts to Keep in Mind

Institute of Scientific and Technical Information of China (English)

刘保行

2005-01-01

I magine life as a game in which you are juggling some five balls in the air.You name them:Work,Family,Health,Friends,Spirit.And you are keeping all of these in the air.You will soon understand that work is a rubber ball.lf you drop it,it will bounce back.But the other four balls-family,health,friends and spirit are made of glass.lf you drop one of these,they will be irrevocably scuffed,marked,nicked,damaged or even shattered .They will never be the same.You must understand that and strive for balance inyour life.

KEEP Reading Research: 1972-1975. Technical Report No. 57.

Science.gov (United States)

Au, Kathryn H.

This report presents a summary of reading research conducted by the Kamehameha Early Education Program (KEEP) during 1972-75. Research was conducted in four areas: student industriousness, reading readiness, teaching of sound-symbol relationships, and language (especially dialect interference). With regard to industriousness, it was found that…

75 FR 76781 - Reports, Forms, and Record Keeping Requirements

Science.gov (United States)

2010-12-09

... conducted with persons on cell phones, a single user of the cell phone will be selected. Each sample member... DEPARTMENT OF TRANSPORTATION National Highway Traffic Safety Administration [U.S. DOT Docket No. NHTSA-2010-0157] Reports, Forms, and Record Keeping Requirements AGENCY: National Highway Traffic Safety...

40 CFR 63.5915 - What records must I keep?

Science.gov (United States)

2010-07-01

... Standards for Hazardous Air Pollutants: Reinforced Plastic Composites Production Notifications, Reports, and... section, when complying with the percent reduction and/or lbs/ton requirements specified in paragraphs (a... determine percent reduction and/or lbs/ton as applicable; (2) You must keep a brief description of the...

How to Keep Your Campus Safe from Infection

Science.gov (United States)

Brown, Scott

2005-01-01

In this article, the author explains how antivirus programs work. He also explains how performances of various antivirus programs vary from one to another. He also takes a look at 13 antivirus programs and explains which of these will keep computers protected. These programs include: (1) Sophos Anti-Virus Version 3.86.2; (2) McAfee VirusScan 9.0;…

Chair's Address: Voices of the Company We Keep

Science.gov (United States)

Anokye, Akua Duku

2007-01-01

This article presents a written version of the address Akua Duku Anokye, chairwoman of the Conference on College Composition and Communication (CCCC), gave at the CCCC meeting in New York on March 24, 2007. In her address, Anokye talked about the importance of how an entity or an individual is known by the company they keep. To learn with whom has…

The extent and characteristics of United Kingdom hospital pharmacists keeping, or not keeping, a professional development portfolio.

Science.gov (United States)

Kostrzewski, Andrzej J; Dhillon, Soraya; Goodsman, Danë; Taylor, Kevin M G; Weinman, John A

2009-10-01

The aim of this study was to examine the use of continuing professional development (CPD) portfolios by hospital pharmacists. The objectives were to assess the extent to which pharmacists use portfolios in CPD and to examine the attitudes/beliefs which differentiate those who do and do not keep a portfolio. Participants completed two questionnaires: (1) personality traits were examined using the Big-Five questionnaire and (2) a new Pharmacist Portfolio-Engaging Behaviour Questionnaire (PPEBQ) examined the attitudes and beliefs. What constitutes a portfolio was left to the interpretation of the participants, but it was specified that the survey was about participants' views of producing written records of their professional practice for CPD. The setting was hospital pharmacists based in the London area in December 2004. Overall, 134 pharmacists (78%) returned both questionnaires, and 80 stated that they kept a portfolio and 52 stated that they did not (two questionnaires were returned spoilt). There was no significant difference in the age or number of years qualified between those with and without a portfolio. Three personality traits were linked to keeping a portfolio (conscientiousness, agreeableness and emotional stability). Pharmacists with a portfolio scored highly on the perceived behavioural control and behavioural intention scales of the PPEBQ. The Big-Five personality questionnaire is a useful tool to investigate pharmacists' use of a portfolio. Results of the PPEBQ suggested that hospital pharmacists who had a portfolio were concerned with having control over its production. However, the PPEBQ requires further development to improve its reliability. These findings have implications for the educational support of CPD.

Modern Time as Historical Artifact

DEFF Research Database (Denmark)

Nye, David Edwin

2015-01-01

Explores different aspects of how Americans have understood and used time since the late eighteenth century through the historical transition that has led to the present 24/7 world, where time-keeping is built into a myriad of devices that record and to some degree direct our actions....

Keeping education fresh-not just in microbiology.

Science.gov (United States)

Fahnert, Beatrix

2017-11-15

Innovative practice from around the globe, addressing a range of recent educational themes and trends, was published in the FEMS Microbiology Letters virtual Thematic Issue 'Keeping Education Fresh' in October 2017. Its thought-provoking content is reviewed here to more directly facilitate reflections and discussions in the professional community. The focus is on best practice approaches when enhancing student engagement, how to adjust those to the diversity of learners, learning situations and infrastructures, and to a broad range of subjects. The need for authentic learning and to move away from didactic teaching is emphasized. The 'students as researchers' theme is featured e.g. in context of service learning. Creative approaches are presented such as using performing arts, popular culture and gamification. The development of interdisciplinary and intercultural competences, and the exploration of socioscientific themes and philosophical issues are considered. Revisions of curricula and programmes, reflective of educational advancements and sector drivers, are discussed from undergraduate to postgraduate and professional specialist level also in light of problem-based learning, interactive distance and on-campus learning, and even the legacy of Massive Open Online Courses. Such changes always require resources and skills, and carry risks. Yet, innovation is a risk worth taking to keep education fresh. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Deep sequencing of the mitochondrial genome reveals common heteroplasmic sites in NADH dehydrogenase genes.

Science.gov (United States)

Liu, Chunyu; Fetterman, Jessica L; Liu, Poching; Luo, Yan; Larson, Martin G; Vasan, Ramachandran S; Zhu, Jun; Levy, Daniel

2018-03-01

Increasing evidence implicates mitochondrial dysfunction in aging and age-related conditions. But little is known about the molecular basis for this connection. A possible cause may be mutations in the mitochondrial DNA (mtDNA), which are often heteroplasmic-the joint presence of different alleles at a single locus in the same individual. However, the involvement of mtDNA heteroplasmy in aging and age-related conditions has not been investigated thoroughly. We deep-sequenced the complete mtDNA genomes of 356 Framingham Heart Study participants (52% women, mean age 43, mean coverage 4570-fold), identified 2880 unique mutations and comprehensively annotated them by MITOMAP and PolyPhen-2. We discovered 11 heteroplasmic "hot" spots [NADH dehydrogenase (ND) subunit 1, 4, 5 and 6 genes, n = 7; cytochrome c oxidase I (COI), n = 2; 16S rRNA, n = 1; D-loop, n = 1] for which the alternative-to-reference allele ratios significantly increased with advancing age (Bonferroni correction p < 0.001). Four of these heteroplasmic mutations in ND and COI genes were predicted to be deleterious nonsynonymous mutations which may have direct impact on ATP production. We confirmed previous findings that healthy individuals carry many low-frequency heteroplasmy mutations with potentially deleterious effects. We hypothesize that the effect of a single deleterious heteroplasmy may be minimal due to a low mutant-to-wildtype allele ratio, whereas the aggregate effects of many deleterious mutations may cause changes in mitochondrial function and contribute to age-related diseases. The identification of age-related mtDNA mutations is an important step to understand the genetic architecture of age-related diseases and may uncover novel therapeutic targets for such diseases.

Furfural reduction mechanism of a zinc-dependent alcohol dehydrogenase from Cupriavidus necator JMP134

Science.gov (United States)

Kang, ChulHee; Hayes, Robert; Sanchez, Emiliano J.; Webb, Brian N.; Li, Qunrui; Hooper, Travis; Nissen, Mark S.; Xun, Luying

2012-01-01

Summary FurX is a tetrameric Zn-dependent alcohol dehydrogenase (ADH) from Cupriavidus necator JMP134. The enzyme rapidly reduces furfural with NADH as the reducing power. For the first time among characterized ADHs, the high-resolution structures of all reaction steps were obtained in a time-resolved manner, thereby illustrating the complete catalytic events of NADH-dependent reduction of furfural and the dynamic Zn2+ coordination among Glu66, water, substrate and product. In the fully closed conformation of the NADH complex, the catalytic turnover proved faster than observed for the partially closed conformation due to an effective proton transfer network. The domain motion triggered by NAD(H) association/dissociation appeared to facilitate dynamic interchanges in Zn2+ coordination with substrate and product molecules, ultimately increasing the enzymatic turnover rate. NAD+ dissociation appeared to be a slow process, involving multiple steps in concert with a domain opening and reconfiguration of Glu66. This agrees with the report that the cofactor is not dissociated from FurX during ethanol-dependent reduction of furfural, in which ethanol reduces NAD+ to NADH that is subsequently used for furfural reduction. PMID:22081946

22 CFR 507.8 - Recording keeping of closed meetings.

Science.gov (United States)

2010-04-01

... of a meeting, closed to the public. (b) The Board, after review by the Chairman, shall make promptly... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Recording keeping of closed meetings. 507.8 Section 507.8 Foreign Relations BROADCASTING BOARD OF GOVERNORS RULES FOR IMPLEMENTING OPEN MEETINGS UNDER...

40 CFR 270.315 - What air emissions control information must I keep at my facility?

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 26 2010-07-01 2010-07-01 false What air emissions control information... Facility § 270.315 What air emissions control information must I keep at my facility? If you have air emission control equipment subject to 40 CFR part 264, subpart CC, you must keep the following information...

Keeping our heads above water: A systematic review of fatal ...

African Journals Online (AJOL)

Keeping our heads above water: A systematic review of fatal drowning in South Africa. ... identify gaps in the current knowledge base and priority intervention areas. ... A total of 13 published research articles and 27 reports obtained through a ...

A Nordic survey of management practices and owners' attitudes towards keeping horses in groups.

Science.gov (United States)

Hartmann, E; Bøe, K E; Christensen, J W; Hyyppä, S; Jansson, H; Jørgensen, G H M; Ladewig, J; Mejdell, C M; Norling, Y; Rundgren, M; Särkijärvi, S; Søndergaard, E; Keeling, L J

2015-09-01

address the extent to which being a part-time member of a group affects horse welfare. For permanent group housing to become more widespread, such as it is the case for most farm animals, future research could focus on solving some of the reoccurring problems perceived with keeping horses in groups. The dissemination of evidence-based information on all aspects around keeping horses in groups can ultimately stimulate further positive changes in the management of group-kept horses.

Hard times; Schwere Zeiten

Energy Technology Data Exchange (ETDEWEB)

Grunwald, Markus

2012-10-02

The prices of silicon and solar wafers keep dropping. According to market research specialist IMS research, this is the result of weak traditional solar markets and global overcapacities. While many manufacturers are facing hard times, big producers of silicon are continuing to expand.

Keep Young Riders Safe (A Minute of Health with CDC)

Centers for Disease Control (CDC) Podcasts

2014-02-06

Motor vehicle-related injuries are a leading cause of death among children in the U.S. This podcast discusses ways to keep kids safe in vehicles.  Created: 2/6/2014 by MMWR.   Date Released: 2/6/2014.

Keeping space public : Times Square (New York and the Senegalese peddlers

Directory of Open Access Journals (Sweden)

Stéphane Tonnelat

2007-03-01

Full Text Available This paper explores the public nature of Times Square's physical and represented (TV, internet, press spaces through an analysis of the techniques used by Senegalese male peddlers to sell souvenirs to the visiting tourists. Whereas a number of scholars denounce the Disneyfication of Times Square, in other words its privatization, the observation of the peddlers shows that there is an almost self-regulated social order of the flow escaping the control of the pseudo-public institution in charge of Times Square, the Business Improvement District. On the other hand, the difficulties encountered by the vendors also reveal another Times square, less public, constituted by the accumulation of images captured by the finance and media companies settled in the office towers. This "clean and safe" pseudo-private space (Mitchell and Staeheli 2006 cannot tolerate the presence of the vendors, thus pushing them to the blind spots of the site. It nevertheless relies on the dynamics of the flow, thus preserving a place for the vendors and the public nature of the physical space of Times Square. But how long can this compromise work?

Controller Design and Evaluation of Lane-Keeping-Assistance System for Motorcycles

Science.gov (United States)

Katagiri, Nozomi; Marumo, Yoshitaka; Tsunashima, Hitoshi

This study seeks to design a lane keeping controller for motorcycles and to evaluate it by computer simulation with a four-degree-of-freedom model and a rider control model. We applied the optimal control theory to the lane keeping controller as a model-based control. By examining the computer simulation with the rider-in-the-loop system consisting of the motorcycle, the controller, and the rider control model, good lane following performance is achieved without interference between the control input and the rider's input. In addition, the virtual point regulator, which compensates the lateral displacement at the virtual point ahead of the vehicle, corresponds to not only the steering torque disturbance but also the lateral force disturbance by choosing the distance to the virtual point.

40 CFR 63.7952 - What records must I keep?

Science.gov (United States)

2010-07-01

... and ongoing determinations for affected sources that are exempt from control requirements under this...., superseded) versions of the plan as required in § 63.8(d)(3). (c) You must keep the records required by this... information in § 63.696(g) for planned routine maintenance of a control device for emissions from process...

Implementation of standards at a research institute. Storage and keeping of radioactive materials following DIN 25422; Umsetzung von Normen in einem Forschungsinstitut. Sichere Aufbewahrung und Lagerung radioaktiver Stoffe nach DIN 25422

Energy Technology Data Exchange (ETDEWEB)

Koeble, T.; Weinand, U. [Fraunhofer-INT, Euskirchen (Germany)

2016-07-01

The secure storage and keeping of radioactive materials is increasingly important especially in times of a growing threat by terrorists. Authorities and users are jointly recommended to adapt the storage and keeping of radioactive materials to increasing security requirements. Here the different possibilities to fulfil the requirements regarding fire prevention and theft prevention which in Germany are set by DIN 25422 were determined for the radioactive materials and their storage and keeping places present in a research institute. The required measures were than agreed about with the relevant authority. Difficulties which are occurring due to the demanding combination of requirements out of the areas of radiation protection, fire prevention, and theft prevention are discussed. The storage and keeping of radioactive materials especially such of high activity requires a high level of security which must be continuously adapted to rising requirements.

Health Beliefs and Co-morbidities Associated with Appointment-Keeping Behavior Among HCV and HIV/HCV Patients.

Science.gov (United States)

Pundhir, Pooja; North, Carol S; Fatunde, Oluwatomilade; Jain, Mamta K

2016-02-01

Appointment-keeping behavior is an important requisite for HCV linkage and treatment initiation. In this study we examine what impact hepatitis C (HCV) knowledge and attitudes has on appointment-keeping behavior among a cohort of HCV and HCV/HIV patients. Knowledge scores and attitude scales, obtained from a cross-sectional survey, were correlated with proportion of appointments kept 1 year prior to taking the survey. Independent risk factors for missing appointments were examined by multiple regression analysis. 292 HCV patients completed the survey, and 149 (51%) were co-infected with HIV. HCV patients kept 67.5 ± 17.4% of their total appointments and a similar proportion (67 ± 38.2) of Liver Clinic appointments, but they attended a higher proportion (73 ± 24.4) of Primary Care Clinic appointments. However, certain health beliefs, psychiatric illness, and HIV co-infection were independently associated with lower levels of appointment-keeping behavior. HCV knowledge was not associated with appointment-keeping behavior. Health beliefs, psychiatric illness, and HIV co-infection are associated with missing appointments, but no link between knowledge and appointment keeping behavior is apparent. In order to increase engagement into HCV care, HCV care coordination programs need to focus on addressing health beliefs and providing resources to those at highest risk for missing appointments.

Oxygen reduction activity of carbon fibers cathode, and application for current generation from the NAD+ and NADH recycling reaction

Directory of Open Access Journals (Sweden)

H. Maeda

2012-03-01

Full Text Available Carbon fibers treated at 700 oC for 10 min were found to have O2 reduction activity when being used as a cathode. The special type of partition combined with both cationic and anionic exchange membranes was applied between anode cell and cathode cell in order to use a highly acidic solution such as 0.5 M H2SO4 as an electrolyte of the cathode cell for increasing the efficiency of O2 reduction activity. The current generation from NAD+ and NADH recycling system combined with D-gluconolactone production from 500 mg of D-glucose was performed by applying only carbon fibers for both anode and cathode. The total current volume obtained was 81.4 mAh during the reaction for 10 h, and the current efficiency was 93%. One gram of carbon fibers was pressed with Nafion paste on a piece of carbon paper(area : 50 mm×50mm with heating to prepare the cathode, and this construct was combined with conventional fuel cell. The power density was 3.6 mW/cm2, and the total power volume was calculated to be 90 mW per 1 g of carbon fibers.

Hypomethylation mediated by decreased DNMTs involves in the activation of proto-oncogene MPL in TK6 cells treated with hydroquinone.

Science.gov (United States)

Liu, Linhua; Ling, Xiaoxuan; Liang, Hairong; Gao, Yuting; Yang, Hui; Shao, Junli; Tang, Huanwen

2012-03-25

Hydroquinone (HQ), one of the most important metabolites derived from benzene, is known to be associated with acute myelogenous leukemia (AML) risk, however, its carcinogenic mechanism remains unclear. In this study, the epigenetic mechanism of HQ exposure was investigated. We characterized the epigenomic response of TK6 cells to HQ exposure, and examined the mRNA expression of DNA methyltransferases (DNMTs) including DNMT1, DNMT3a and DNMT3b, methyl-CpG-binding domain protein 2 (MBD2) and six proto-oncogenes (MPL, RAF1, MYB, MYC, ERBB2 and BRAF). Compared to the control cells, HQ exposure (2.5, 5.0, 10.0 and 20.0 μM for 48 h) resulted in the decrease of DNMTs and MBD2 expression, the global hypomethylation and increase of MPL at mRNA level. Meanwhile, most of these changes were in dose-dependent manner. Moreover, inhibition of DNMTs induced by 5-aza-2'-deoxycytidine (5-AZA), an identified DNMT inhibitor, caused more induction of MPL expression at mRNA level compared to the HQ (10.0 μM) pre-treated group. Furthermore, treatment of HQ potentially led to MPL itself hypomethylation (10.0 and 20.0 μM reduced by 47% and 44%, respectively), further revealing that the activation of proto-oncogene MPL was related to hypomethylation in its DNA sequences. In conclusion, hypomethylation, including global and specific hypomethylation, might be involved in the activation of MPL, and the hypomethylation could be induced by decreased DNMTs in TK6 cells exposed to HQ. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Experience of introducing a new database for an approved coordination and record keeping service

International Nuclear Information System (INIS)

Garratt, N. J.

2011-01-01

The Health Protection Agency (and its predecessors) has many years experience of running Approved Dosimetry Services, including coordination and record keeping. This paper describes the experiences gained whilst introducing a new web-based system for coordination and record keeping to replace the ageing mainframe database. This includes the planning of the project, the migration of the data between the two systems, parallel running of all the operational tasks and lessons learned during the process. (authors)

Frequency-domain criterion for the chaos synchronization of time ...

Indian Academy of Sciences (India)

of time-delay power systems under linear feedback control ... arbitrary dimension of the time-delay systems can keep their chaotic characteristic as long as ... As a basic theory on chaotic secure communication, synchronization of time-delay.

The ANKLe Score: An Audit of Otolaryngology Emergency Clinic Record Keeping

Science.gov (United States)

Dexter, Sara C; Hayashi, Daichi; Tysome, James R

2008-01-01

INTRODUCTION Accurate and legible medical records are essential to good quality patient care. Guidelines from The Royal College of Surgeons of England (RCSE) state the content required to form a complete medical record, but do not address legibility. An audit of otolaryngology emergency clinic record keeping was performed using a new scoring system. PATIENTS AND METHODS The Adjusted Note Keeping and Legibility (ANKLe) score was developed as an objective and quantitative method to assess both the content and legibility of case notes, incorporating the RCSE guidelines. Twenty consecutive otolaryngology emergency clinic case notes from each of 7 senior house officers were audited against standards for legibility and content using the ANKLe score. A proforma was introduced to improve documentation and handwriting advice was given. A further set of 140 notes (20 notes for each of the 7 doctors) was audited in the same way to provide feedback. RESULTS The introduction of a proforma and advice on handwriting significantly increased the quality of case note entries in terms of content, legibility and overall ANKLe score. CONCLUSIONS Accurate note keeping can be improved by the use of a proforma. The legibility of handwriting can be improved using simple advice. The ANKLe score is an objective assessment tool of the overall quality of medical note documentation which can be adapted for use in other specialties. PMID:18430339

Management Matters: Planning Goals and Time

Science.gov (United States)

Pappas, Marjorie L.

2004-01-01

This article discusses the importance of setting and implementing goals that can help change and improve a library media program over time--goals that go beyond merely keeping the library media center running. Suggestions for developing an action plan and strategies for effective time management are also presented.

You're Never Too Old: Keep Active as You Age

Science.gov (United States)

... people age 85 and older. Experts recommend four types of exercise for older adults: endurance, balance, strength, and ... started and keep moving, NIH brought together some of the nation’s leading experts on aging, exercise, and motivation. They developed a guide to exercise for older ...

Keep Young Riders Safe (A Cup of Health with CDC)

Centers for Disease Control (CDC) Podcasts

Motor vehicle-related injuries are a leading cause of death among children in the United States. Adults can prevent many of these tragedies by properly securing children in vehicles. In this podcast, Dr. Erin Sauber-Schatz discusses ways to keep kids safe in vehicles.

Synthesis of gold nanorods with a longitudinal surface plasmon resonance peak of around 1250 nm

Science.gov (United States)

Nguyen, Thi Nhat Hang; Le Trinh Nguyen, Thi; Thanh Tuyen Luong, Thi; Thang Nguyen, Canh Minh; Nguyen, Thi Phuong Phong

2016-03-01

We prepared gold nanorods and joined them to chemicals such as tetrachloauric (III) acid trihydrate, silver nitrate, hydroquinone, hexadecyltrimethylammonium bromide, sodium hydroxide and sodium borohydride using the seed-mediated method. The combination of hydroquinone, with or without salicylic acid, influences the size of the gold nanorods, and this is demonstrated by the results of TEM images, UV-vis spectra and the value of the longitudinal surface plasmon resonance peak with respect to the UV-vis spectra. By changing the Ag+ ion and hydroquinone concentration and the combination of hydroquinone and salicylic acid, the size of the gold nanorods can be controlled and this is manifested by longitudinal surface plasmon resonance peaks forming between 875 and 1278 nm. In particular, sample E2 achieved a longitudinal surface plasmon peak at 1273 nm and an aspect ratio of more than 10 by modifying the hydroquinone to 2.5 mM and salicylic acid to 0.5 mM concentration in the growth solution.

Keeping Pace with K-12 Online & Blended Learning: An Annual Review of Policy and Practice, 2013

Science.gov (United States)

Watson, John; Murin, Amy; Vashaw, Lauren; Gemin, Butch; Rapp, Chris

2013-01-01

This is the 10th annual "Keeping Pace" report. "Keeping Pace" has several goals: (1) add to the body of knowledge about online education policy and practice, and make recommendations for advances; (2) serve as a reference source for information about programs and policies across the country, both for policymakers and…

Evolutionary Policy Transfer and Search Methods for Boosting Behavior Quality: RoboCup Keep-Away Case Study

Directory of Open Access Journals (Sweden)

Geoff Nitschke

2017-11-01

Full Text Available This study evaluates various evolutionary search methods to direct neural controller evolution in company with policy (behavior transfer across increasingly complex collective robotic (RoboCup keep-away tasks. Robot behaviors are first evolved in a source task and then transferred for further evolution to more complex target tasks. Evolutionary search methods tested include objective-based search (fitness function, behavioral and genotypic diversity maintenance, and hybrids of such diversity maintenance and objective-based search. Evolved behavior quality is evaluated according to effectiveness and efficiency. Effectiveness is the average task performance of transferred and evolved behaviors, where task performance is the average time the ball is controlled by a keeper team. Efficiency is the average number of generations taken for the fittest evolved behaviors to reach a minimum task performance threshold given policy transfer. Results indicate that policy transfer coupled with hybridized evolution (behavioral diversity maintenance and objective-based search addresses the bootstrapping problem for increasingly complex keep-away tasks. That is, this hybrid method (coupled with policy transfer evolves behaviors that could not otherwise be evolved. Also, this hybrid evolutionary search was demonstrated as consistently evolving topologically simple neural controllers that elicited high-quality behaviors.

NADH:ubiquinone reductase and succinate dehydrogenase activity in the liver of rats with acetaminophen-induced toxic hepatitis on the background of alimentary protein deficiency

Directory of Open Access Journals (Sweden)

G. P. Kopylchuk

2015-02-01

Full Text Available The ratio between the redox forms of the nicotinamide coenzymes and key enzymatic activity of the I and II respiratory chain complexes in the liver cells mitochondria of rats with acetaminophen-induced hepatitis under the conditions of alimentary deprivation of protein was studied. It was estimated, that under the conditions of acute acetaminophen-induced hepatitis of rats kept on a low-protein diet during 4 weeks a significant decrease of the NADH:ubiquinone reductase and succinate dehydrogenase activity with simultaneous increase of the ratio between redox forms of the nicotinamide coenzymes (NAD+/NADН is observed compared to the same indices in the liver cells of animals with experimental hepatitis kept on the ration balanced by all nutrients. Results of research may become basic ones for the biochemical rationale for the approaches directed to the correction and elimination of the consequences­ of energy exchange in the toxic hepatitis, induced on the background of protein deficiency.

Skin bleaching: highlighting the misuse of cutaneous depigmenting agents.

Science.gov (United States)

Dadzie, O E; Petit, A

2009-07-01

Hydroquinone and other cutaneous depigmenting agents are widely used by dermatologists to treat pigmentary disorders. On 29 August 2006, the US Food and Drug Administration (FDA) published a monograph in the US Federal Register proposing to ban all hydroquinone products that have not been approved via a New Drug Application process. Reports in the scientific literature on the occurrence of exogenous ochronosis, in relation to the use of hydroquinone, was one of the concerns expressed by the FDA in relation to this agent. However, a review of the English-language scientific literature reveals that most of the reported cases of hydroquinone-induced exogenous ochronosis occurs in Africa, where the cultural practice of skin bleaching is highly prevalent. Skin bleaching is the practice of applying hydroquinone and/or other depigmenting agents to specific or widespread areas of the body, the primary function being to lighten normally dark skin. This practice typically occurs in men and women with Fitzpatrick skin phototypes IV to VI. It is a dangerous practice associated with a diverse range of side-effects, including mercury poisoning. Thus, this current discussion within the dermatological community on the safety of hydroquinone provides a unique opportunity to raise awareness about skin bleaching.

Studies of yeast cell oxygenation and energetics by laser fluorometry of reduced nicotinamide adenine dinucleotide

Science.gov (United States)

Pan, Fu-shih; Chen, Stephen; Mintzer, Robert A.; Chen, Chin-Tu; Schumacker, Paul

1991-03-01

It is of fundamental importance for biological scientists to assess cellular energetics. Under aerobic conditions, the tricarboxylic acid cycle (TCA cycle) is coupled with the mitochondrial electron cascade pathway to provide the cell with energy. The nicotinamide adenine dinucleotide-conjugated pair (NAD and NADH) is the coenzyme in numerous important biomedical reactions which include several important dehydrogenase reactions in the TCA cycle. Based on Le Chatelier's principle, NADH will accumulate when this energy production mechanism is impaired. The relative amounts of NAD and NADH in a cell are defined as the redox state of the cell (Williamson et.al. 1967) which provides a valuable index of cellular energetics. The sum of the amounts of NAD and NADH in a cell may be assumed to be constant during a finite time; therefore, a reliable means of measuring the NADH concentration would provide us with a useful indicator of tissue viability. Traditionally, the quantities of NADH and NAD may be measured by chemical assay methods. We can avoid these tediois analyses by exploiting the significant difference between the ultraviolet absorption spectra of this redox pair. However, because of the opacity of biological samples and the interference of other biochemicals that also absorb ultraviolet radiation, measurement of NADH and NAD+ concentrations in vivo by absorption spectroscopy is not feasible.

41 CFR 102-118.80 - Who is responsible for keeping my agency's electronic commerce transportation billing records?

Science.gov (United States)

2010-07-01

... keeping my agency's electronic commerce transportation billing records? 102-118.80 Section 102-118.80... Transportation and Transportation Services § 102-118.80 Who is responsible for keeping my agency's electronic commerce transportation billing records? Your agency's internal financial regulations will identify...

Tax and Record Keeping Information for Family Child Care = Informacion Sobre los Impuestos y la Documentacion para el Cuidado Infantil en el Hogar.

Science.gov (United States)

Gellert, Sandra

This pamphlet from the Children's Foundation, in both English- and Spanish-language versions, provides advice to child care providers on record-keeping methods. The pamphlet also gives definitions and guidance on business expenses (100% deductible, shared personal and business, and depreciated capital expenses), time-space formula, self-employment…

FAMILY AND SELF-KEEPING BEHAVIOR OF YOUTH

Directory of Open Access Journals (Sweden)

B.S. Pavlov

2008-06-01

Full Text Available In this paper actual problems of self-keeping behavior and healthy mode of life of youth in the Urals are considered. The role of family in psychological education of children and teenagers is analyzed. As empirical base for the analysis of the declared problem and conclusions for the author the results of some sociological interrogations lead by him in 1990-2007 in the Institute of economy of the Ural Branch of Russian academy of sciences in various cities and settlements of subjects of the Russian Federation, amounting to the Ural federal district are used.

Time-interpolator

International Nuclear Information System (INIS)

Blok, M. de; Nationaal Inst. voor Kernfysica en Hoge-Energiefysica

1990-01-01

This report describes a time-interpolator with which time differences can be measured using digital and analog techniques. It concerns a maximum measuring time of 6.4 μs with a resolution of 100 ps. Use is made of Emitter Coupled Logic (ECL) and analogues of high-frequency techniques. The difficulty which accompanies the use of ECL-logic is keeping as short as possible the mutual connections and closing properly the outputs in order to avoid reflections. The digital part of the time-interpolator consists of a continuous running clock and logic which converts an input signal into a start- and stop signal. The analog part consists of a Time to Amplitude Converter (TAC) and an analog to digital converter. (author). 3 refs.; 30 figs

How Can I Keep Track of Physical Activity and Eating?

Science.gov (United States)

... ANSWERS by heart Lifestyle + Risk Reduction Fitness + Weight Management How Can I Keep Track of Physical Activity and Healthy Eating? Food Diary — Once you’ve set your eating goals, use this sample chart to track your efforts. WEEK: ________________________ DAY: ________________________ Food or Beverage Amount Number of Calories Grams of Saturated Fat ...

17 CFR 1.31 - Books and records; keeping and inspection.

Science.gov (United States)

2010-04-01

... exclusively in a non-rewritable, non-erasable format; (B) Verifies automatically the quality and accuracy of... immediately provide at the expense of the person required to keep such records, any easily readable hard-copy... or the Department of Justice may request. Records must use a format and coding structure specified in...

Electrochemical studies of redox probes in self-organized lyotropic ...

Indian Academy of Sciences (India)

Administrator

quinone|hydroquinone, methyl viologen and ferrocenemethanol probes in a lyotropic hexagonal columnar phase (H1 phase) using cyclic voltammetry and electrochemical impedance ..... hydrogen bond of hydroquinone during oxidation is.

Time Analysis: Still an Important Accountability Tool.

Science.gov (United States)

Fairchild, Thomas N.; Seeley, Tracey J.

1994-01-01

Reviews benefits to school counselors of conducting a time analysis. Describes time analysis system that authors have used, including case illustration of how authors used data to effect counseling program changes. System described followed process outlined by Fairchild: identifying services, devising coding system, keeping records, synthesizing…

Topological and organizational properties of the products of house-keeping and tissue-specific genes in protein-protein interaction networks.

Science.gov (United States)

Lin, Wen-Hsien; Liu, Wei-Chung; Hwang, Ming-Jing

2009-03-11

Human cells of various tissue types differ greatly in morphology despite having the same set of genetic information. Some genes are expressed in all cell types to perform house-keeping functions, while some are selectively expressed to perform tissue-specific functions. In this study, we wished to elucidate how proteins encoded by human house-keeping genes and tissue-specific genes are organized in human protein-protein interaction networks. We constructed protein-protein interaction networks for different tissue types using two gene expression datasets and one protein-protein interaction database. We then calculated three network indices of topological importance, the degree, closeness, and betweenness centralities, to measure the network position of proteins encoded by house-keeping and tissue-specific genes, and quantified their local connectivity structure. Compared to a random selection of proteins, house-keeping gene-encoded proteins tended to have a greater number of directly interacting neighbors and occupy network positions in several shortest paths of interaction between protein pairs, whereas tissue-specific gene-encoded proteins did not. In addition, house-keeping gene-encoded proteins tended to connect with other house-keeping gene-encoded proteins in all tissue types, whereas tissue-specific gene-encoded proteins also tended to connect with other tissue-specific gene-encoded proteins, but only in approximately half of the tissue types examined. Our analysis showed that house-keeping gene-encoded proteins tend to occupy important network positions, while those encoded by tissue-specific genes do not. The biological implications of our findings were discussed and we proposed a hypothesis regarding how cells organize their protein tools in protein-protein interaction networks. Our results led us to speculate that house-keeping gene-encoded proteins might form a core in human protein-protein interaction networks, while clusters of tissue-specific gene

Standards for collection of identifying information for health record keeping

International Nuclear Information System (INIS)

Carpenter, M.; Fair, M.E.; Lalonde, P.; Scott, T.

1988-09-01

A new recommended guideline for the standard data collection of individual identifying information has been developed and tested by Statistics Canada. The purpose of developing a standard method is to improve health record keeping in Canada: in particular for long term medical follow-up studies of individuals exposed to potentially hazardous agents for detection of possible health risks or delayed harm, e.g. individuals exposed to radiation through occupations, the environment, emergencies, or therapeutic practice. A data collection standard is also useful for epidemiological follow-up studies for other occupation groups such as chemical workers and miners, or for lifestyle, genetic and other studies. Statistics Canada, Health Division, Occupational and Environmental Health Research Unit (OEHRU), from their experience with long term health studies using the Canadian Mortality Data Base, has prepared a 'Data Collection Package' to include the developed and tested data collection guideline. It is anticipated this will help produce more thorough and comparable on-going record keeping while saving costs and time for many organizations e.g. Atomic Energy Control Board licensees who report radiation doses to the National Dose Registry, as well as for other companies and organizations across the country where long term medical follow-up studies are anticipated now or in the future. It may also allow for broader industrial, national and international comparisons. The guideline consists of a two page Individual Identity Summary (IIS): the first page for completion by the individual/employee to give unique identifying information; the second page for the study organizer/employer to include essential additional information (work history etc.). A third optional page can be used by organizations wishing to collect data on children. The Data Collection Package also includes brief explanatory notes, a suggested file record layout and detailed computer coding advice for entering

Keep Your Voice Sound: How to Prevent and Avoid Voice Problems

Science.gov (United States)

... Brain Listen Up! Wise Choices Avoid Voice Problems Drink 6 to 8 glasses of water a day. This helps keep your vocal folds moist and healthy. Limit intake of caffeinated or alcoholic drinks. These can dehydrate your body and make the ...

Keep in touch (KIT): perspectives on introducing internet-based communication and information technologies in palliative care.

Science.gov (United States)

Guo, Qiaohong; Cann, Beverley; McClement, Susan; Thompson, Genevieve; Chochinov, Harvey Max

2016-08-02

Hospitalized palliative patients need to keep in touch with their loved ones. Regular social contact may be especially difficult for individuals on palliative care in-patient units due to the isolating nature of hospital settings. Technology can help mitigate isolation by facilitating social connection. This study aimed to explore the acceptability of introducing internet-based communication and information technologies for patients on a palliative care in-patient unit. In the first phase of the Keep in Touch (KIT) project, a diverse group of key informants were consulted regarding their perspectives on web-based communication on in-patient palliative care units. Participants included palliative patients, family members, direct care providers, communication and information technology experts, and institutional administrators. Data was collected through focus groups, interviews and drop-in consultations, and was analyzed for themes, consensus, and major differences across participant groups. Hospitalized palliative patients and their family members described the challenges of keeping in touch with family and friends. Participants identified numerous examples of ways that communication and information technologies could benefit patients' quality of life and care. Patients and family members saw few drawbacks associated with the use of such technology. While generally supportive, direct care providers were concerned that patient requests for assistance in using the technology would place increased demands on their time. Administrators and IT experts recognized issues such as privacy and costs related to offering these technologies throughout an organization and in the larger health care system. This study affirmed the acceptability of offering internet-based communication and information technologies on palliative care in-patient units. It provides the foundation for trialing these technologies on a palliative in-patient unit. Further study is needed to confirm the

Academic Value of Non-Academics: The Case for Keeping Extracurriculars

Science.gov (United States)

Kronholz, June

2012-01-01

With school districts struggling to keep their noses above choppy budget waters and voters howling about taxes, should schools be funding Ping-Pong and trading-card clubs? Swim teams, moot court, powder puff football? Latino unions, gay-straight alliances, the Future Business Leaders of America, the French Honors Society, the jazz band, the…

The book-keeping program INDEX

International Nuclear Information System (INIS)

Johansson, H.

1975-12-01

When the automatic measuring device for bubble chamber film, the Spiral Reader, at the Institute of Physics, University of Stockholm, came into operation in 1971, the 19 GeV/c pd-experiment was the first one to use it. New software was needed in order to process events, found in the scanning to the Spiral Reader for measurement. This piece of software should also be able to combine information from different scans into one unique record of necessary information per event. It was also desirable that this software could keep track of the events when further processed through the bubble chamber chain of programs. In addition it was wanted that events, which failed somewhere in the program chain, were not further processed, but instead were selected for remeasurement or rerunning if there was hope to get them through by such a procedure. The program called INDEX was constructed according to these demands. (Auth.)

Supporting Early Warning Systems: Using Data to Keep Students on Track to Success. Data for Action 2012

Science.gov (United States)

Data Quality Campaign, 2012

2012-01-01

Supporting early warning systems is important because keeping students on track is vital to graduating all students college and career ready. Failing to keep students on track toward completing high school has perilous consequences for students, communities, and the economy. Predictive analyses are important to ensuring students are on track.…

Production of Imitated fish and Keeping their Quality by gamma irradiation

International Nuclear Information System (INIS)

Ali, H.E.S.

2004-01-01

this investigation aims to the possibility of utilizing the bolti fish which obtained from high dam lake specially large size and under utilized for manufacturing imitated shellfish product and compared with natural shell fish and also, aims to study the possibility of gamma irradiation at doses 1,3,and 5 kGy for keeping the quality of imitated fish product during cold storage. therefore whole fish bolti were obtained from Misr Aswan company. the whole fish were dressed and minced. the obtained minced fish was washed three times with sodium bicarbonate (0.2%), distilled water and sodium chloride solution (0.15%). the cryoprotectant ingredient (sorbitol, sucrose and tripoli phosphate) was added to washed minced fish for producing intermediate product (surimi). the final product (imitated fish) was manufactured by adding egg white, starch, corn oil, natural color and flavor of shrimp and crab according to special formula for shrimp and crab. the imitated shrimp sample were irradiated at doses 1,3 and 5 kGy and sold stored

System for keeping atmospheric pressure in nuclear facility and its peripheral equipments

International Nuclear Information System (INIS)

Matsumoto, Hatsuo

1993-02-01

The design to keep radioactive materials in the facility and not to make them spread inside the facility and into the environments is an essential issue in the construction of nuclear facilities. One reason of the contamination is due to the diffusion with air flow, therefore, negative pressure for the ambients has been utilized to keep gaseous radioactivities inside the facility of interest. The pressure difference is not so large, though, the atmospheric pressure level of the contaminated and possibly contaminated areas are always kept to be lower than those of the ambient one to prevent the dissemination of radioactivity from the defined area. The technique using negative pressure, at present, is employed widely in nuclear facilities, and the basic system is the same as that of JRR-1 built as the first nuclear facility in Japan. In the present work, the conventional system with negative pressure was reexamined on the sate-of-art of the regulations for the nuclear facilities, and consequently some shortages of the system has been found. Thus, an advanced system with an excellent performance keeping the negative pressure has been developed to cover the shortage. In this report, the new system is introduced with a couple of comments, acquired from the author's experience, to the design and the maintenance of the composite equipments of the system. (author)

Radioactive Substances Act 1960. Keeping and use of radioactive materials; list of registrations in England and Wales issued under the Radioactive Substances Act 1960 for the keeping and use of radioactive materials and mobile

International Nuclear Information System (INIS)

1989-05-01

Through the Radioactive Substances Act 1960 (RSA 60), Her Majesty's Inspectorate of Pollution (Radioactive Substances) (HMIP) exercises control, on behalf of the Secretary of State for the Environment, over the keeping and use of radioactive material and the accumulation and disposal of radioactive waste in England. HMIP also provides technical advice to the Secretary of State for Wales in connection with the enforcement of RSA 60 in Wales. Registrations under RSA 60 for the keeping and use of radioactive materials in England and Wales are issued respectively by the Secretaries of State for the Environment and Wales, following careful assessment of the radiological consequences for members of the public. Registrations impose strict limits and conditions and premises and apparatus are subject to scrutiny by HMIP Inspectors to ensure compliance. A list contains names and addresses of those registered in England and Wales for the keeping and use of radioactive materials and mobile apparatus

Effects of maternal gate-keeping behavior on father involvement in care of a pre-school child

Directory of Open Access Journals (Sweden)

Mihić Ivana

2010-01-01

Full Text Available The research so far indicates that the context in which the father’s role takes place significantly influences the form and level of father involvement in taking care of the child. The primary goal of this research was to describe the forms and effects of maternal gate-keeping behavior as a characteristic form of interaction between parents which is, as part of the context, considered a significant factor in father involvement in care of the child. Research participants were 247 parental couples from complete families whose oldest child attended a pre-school institution. Fathers provided assessments of their own involvement via the Father Involvement Inventory, as well as assessments of prominence of gate-keeping behavior in their wives via the checklist of maternal gate-keeping behavior. Mothers reported on their beliefs about the importance and possibilities of father involvement in care of the child, as well as on their personal satisfaction with the current involvement of their husband in the joint care of the child. The results point out to the particular forms of mothers’ ambivalence when it comes to the joint care of the child, which is a form of gate-keeping behavior. The frequency of gate-keeping behavior, assessed by the checklist, significantly changes the possibilities of father involvement in taking care of the child in the developmental phase of the family, having in mind that the task of this phase is precisely the definition of parental roles and formation of parent cooperative principle.

32 CFR 37.910 - How long must I require participants to keep records related to the TIA?

Science.gov (United States)

2010-07-01

... records related to the TIA? 37.910 Section 37.910 National Defense Department of Defense OFFICE OF THE... require participants to keep records related to the TIA? Your TIA must require participants to keep records related to the TIA (for which the agreement provides Government access under § 37.915) for a...

Managing "keep" factors of office tenants to raise satisfaction and loyalty

NARCIS (Netherlands)

Appel - Meulenbroek, H.A.J.A.

2008-01-01

Purpose – The purpose of this paper is to add to behavioural property literature and improve the landlord-tenant relationship, through exploring the effect of office (location and building) "keep", push and pull factors on satisfaction and loyalty of tenants. Design/methodology/approach – Structured

Keeping Children Safe: Afterschool Staff and Mandated Child Maltreatment Reporting

Science.gov (United States)

Gandarilla, Maria; O'Donnell, Julie

2014-01-01

With 8.4 million children in the U.S. spending an average of eight hours a week in afterschool programs, afterschool providers are an important part of the network of caring adults who can help to keep children safe. In addition, afterschool staff are "mandated reporters." Whether or not the laws specifically mention afterschool staff,…

Keep Young Riders Safe (A Cup of Health with CDC)

Centers for Disease Control (CDC) Podcasts

2014-02-06

Motor vehicle-related injuries are a leading cause of death among children in the United States. Adults can prevent many of these tragedies by properly securing children in vehicles. In this podcast, Dr. Erin Sauber-Schatz discusses ways to keep kids safe in vehicles.  Created: 2/6/2014 by MMWR.   Date Released: 2/6/2014.

Development of a Real-time PCR test for porcine group A rotavirus diagnosis

Directory of Open Access Journals (Sweden)

Elizabeth C.M. Marconi

2015-01-01

Full Text Available Group A Rotavirus (RVA is one of the most common causes of diarrhea in humans and several animal species. A SYBR-Green Real-Time polymerase chain reaction (PCR was developed to diagnose RVA from porcine fecal samples, targeting amplification of a 137-bp fragment of nonstructural protein 5 (NSP5 gene using mRNA of bovine NADH-desidrogenase-5 as exogenous internal control. Sixty-five samples were tested (25 tested positive for conventional PCR and genetic sequencing. The overall agreement (kappa was 0.843, indicating 'very good' concordance between tests, presenting 100% of relative sensitivity (25+ Real Time PCR/25+ Conventional PCR and 87.5% of relative sensitivity (35- Real Time PCR/40- Conventional PCR. The results also demonstrated high intra- and inter-assay reproducibility (coefficient of variation ≤1.42%; thus, this method proved to be a fast and sensitive approach for the diagnosis of RVA in pigs.

12 CFR 225.175 - What risk management, record keeping and reporting policies are required to make merchant banking...

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 3 2010-01-01 2010-01-01 false What risk management, record keeping and... risk management, record keeping and reporting policies are required to make merchant banking... conduct, monitor and manage such investment activities and the risks associated with such investment...

Keep Kids Current on Vaccines (A Cup of Health with CDC)

Centers for Disease Control (CDC) Podcasts

Twenty years ago, the Vaccines for Children program was created in response to a major measles epidemic. This program provides vaccinations for children whose parents cannot afford them. In this podcast, Dr. Andrew Kroger discusses the importance of keeping children up-to-date on their vaccinations.

Effects of the KEEP Foster Parent Intervention on Child and Sibling Behavior Problems and Parental Stress During a Randomized Implementation Trial.

Science.gov (United States)

Price, Joseph M; Roesch, Scott; Walsh, Natalia E; Landsverk, John

2015-07-01

Children in foster care are at risk for externalizing behavior problems, which can in turn increase the risk of changes in foster care placement. The KEEP (Keeping Foster Parents Trained and Supported) foster parent training intervention was designed to equip foster parents with strategies for managing externalizing behavior problems. The primary goals of this investigation were to (a) examine the effectiveness of the KEEP intervention in reducing child behavior problems, as delivered by a community agency; (b) determine if the effects of the KEEP intervention generalize to more than one child in the same home; and (c) examine the effectiveness of the KEEP intervention in reducing parental stress associated with child behavior problems. The data from 335 foster and kinship families with children between the ages of 5 and 12 years were analyzed to address these objectives. Families were randomly assigned to the intervention or control condition. The results indicated that the KEEP intervention was effective in reducing child behavior problems when delivered by a community agency. These results expanded prior research on the KEEP intervention, revealing that the intervention was effective in reducing the behavior problems of more than one child in the same household and in reducing parental stress levels associated with the behavioral issues of the focal child. Thus, the KEEP intervention model holds promise for reducing the behavior problems of children in foster care and reducing stress levels of foster and kinship caregivers as it is disseminated and implemented within similar child welfare settings.

Investigation of radiation keeping property of barite coated cloth via image processing method

Science.gov (United States)

Kilinçarslan, Ş.; Akkurt, İ.; Molla, T.; Akarslan, F.

2012-09-01

Preservative clothes which are able to absorb radiation beam are needed not only for saving people working at radioactive environment but also for saving others from natural and man-made radiation sources we are exposed in daily life. Barite is a mineral which can be used for armour plating because of high atomic numbered element barium constituent of barite. In this study, armour plating property of barite was applied to fabrics. Barite coated fabric having characteristic of keeping radiation was obtained by penetrating barite on cloth via coating method. Radiation keeping property of fabrics obtained was determined via image processing. The results of experiments showed that barite coated fabrics have blocked radiation more than normal fabrics have done.

Investigation of radiation keeping property of barite coated cloth via image processing method

Energy Technology Data Exchange (ETDEWEB)

Kilincarslan, S.; Akkurt, I.; Molla, T.; Akarslan, F. [Department of Construction Education, Suleyman Demirel University, Isparta (Turkey); Department of Physics, Science Faculty, Suleyman Demirel University, Isparta (Turkey); Department of Construction Education, Suleyman Demirel University, Isparta (Turkey); Textil Engineering, Engineering Faculty, Suleyman Demirel University, Isparta (Turkey)

2012-09-06

Preservative clothes which are able to absorb radiation beam are needed not only for saving people working at radioactive environment but also for saving others from natural and man-made radiation sources we are exposed in daily life. Barite is a mineral which can be used for armour plating because of high atomic numbered element barium constituent of barite. In this study, armour plating property of barite was applied to fabrics. Barite coated fabric having characteristic of keeping radiation was obtained by penetrating barite on cloth via coating method. Radiation keeping property of fabrics obtained was determined via image processing. The results of experiments showed that barite coated fabrics have blocked radiation more than normal fabrics have done.

Investigation of radiation keeping property of barite coated cloth via image processing method

International Nuclear Information System (INIS)

Kilinçarslan, Ş.; Akkurt, İ.; Molla, T.; Akarslan, F.

2012-01-01

Preservative clothes which are able to absorb radiation beam are needed not only for saving people working at radioactive environment but also for saving others from natural and man-made radiation sources we are exposed in daily life. Barite is a mineral which can be used for armour plating because of high atomic numbered element barium constituent of barite. In this study, armour plating property of barite was applied to fabrics. Barite coated fabric having characteristic of keeping radiation was obtained by penetrating barite on cloth via coating method. Radiation keeping property of fabrics obtained was determined via image processing. The results of experiments showed that barite coated fabrics have blocked radiation more than normal fabrics have done.

Combinations of potent topical steroids, mercury and hydroquinone are common in internationally manufactured skin-lightening products: a spectroscopic study.

Science.gov (United States)

Maneli, M H; Wiesner, L; Tinguely, C; Davids, L M; Spengane, Z; Smith, P; van Wyk, J C; Jardine, A; Khumalo, N P

2016-03-01

The topical steroids betamethasone (BM) and clobetasol propionate (CP) are illegal in cosmetics. Hydroquinone (HQ) and mercury (Hg) are either illegal or allowed only in limited concentrations (2% and 1 ppm, respectively). To investigate active ingredients and countries of origin of popular skin-lightening products available in Cape Town, South Africa. In total, 29 products were examined; of these, 22 products were purchased from informal vendors, and 2 products (out of a total of 29) were purchased over the counter. HQ, Hg(2+) and steroids were quantified by high-performance liquid chromatography-ultraviolet spectrophotometry, inductively coupled plasma-mass spectrometry and liquid chromatography-mass spectrometry, respectively. Of the 29 products, 22 (75.9%), all imported and bought from informal vendors, contained illegal or banned ingredients: 13 (44.8%) contained steroids (9 CP, 4 BM), 12 (41.4%) contained Hg (30-2300 ppm), and 11 (37.9%) contained HQ. Sequentially, the products originated from Italy (27.3%, n = 6), India (22.7%, n = 5), the Democratic Republic of Congo (DRC) (22.7%, n = 5), Cote d'Ivoire (9.1%, n = 2), USA (9.1%, n = 2), UK (4.5%, n = 1) and France (4.5%, n = 1). Two products, one from India and one from the DRC, contained all four ingredients (HQ, Hg, BM, CP). Of the 12 products containing Hg, 10 also contained HQ and/or a steroid, yet none listed Hg as an ingredient. A significant proportion of the steroid-containing products (76.9%) also contained at least one other skin-lightening agent. Not all internationally available products were tested, which is a limitation of the study. In spite of a European Union ban on skin lighteners, a third of the products tested were from Europe. Combinations of Hg and ultrapotent steroids were prominent. International law enforcement and random testing is needed to encourage industry compliance and help protect consumers. © 2015 British Association of Dermatologists.

Active aging as a way of keeping diseases at arm’s length

DEFF Research Database (Denmark)

Lassen, Aske Juul

Active ageing has increasingly become the ideal of how to live later life. Concepts of activity, participation and independence are central to how elderly see themselves and practice aging (Katz 2000). The elderly are encouraged and expected to stay active and independent. This is believed...... to be good for their quality of life, health, functionality and the economy (Sundhedsstyrelsen 2008, EC 2006, WHO 2002). At the same time active aging is inscribed into a general health care focus, which individualizes the responsibility for health and disease. This requires subjects ready to self......-care, by paying attention to the signals of the body and leading healthy lives (Rose 2001). However, active aging seems to contain an ambiguity in this aspect, as the practice of active aging is often a way for elderly to keep diseases at arm’s length, and not a way to sense the possible abnormalities in the body...

Electroactive Properties of 1-propyl-3-methylimidazolium Ionic Liquid Covalently Bonded on Mesoporous Silica Surface: Development of an Electrochemical Sensor Probed for NADH, Dopamine and Uric Acid Detection

International Nuclear Information System (INIS)

Maroneze, Camila M.; Rahim, Abdur; Fattori, Natália; Costa, Luiz P. da; Sigoli, Fernando A.; Mazali, Italo O.; Custodio, Rogério; Gushikem, Yoshitaka

2014-01-01

Graphical abstract: - Abstract: A hybrid organic-inorganic porous material was successfully prepared through chemical modification of a non-ordered mesoporous silica, obtained by the sol-gel process, with 1-propyl-3-methylimidazolium groups. The porous material was evaluated as a platform for the development of electrochemical sensors, here probed toward the electrooxidation of NADH (β-nicotinamide adenine dinucleotide), uric acid (UA) and dopamine (DA). The presence of cationic imidazolium groups on the surface of the hybrid silica-based material allowed the electrochemical detection of these biomolecules without any other electron mediator or biomolecular recognition component. Such behavior highlights the potentiality of this material to be applied in the development of new electrochemical sensing devices. Theoretical calculations based on density functional theory emphasizes that the cationic character of imidazolium group provides better oxidation conditions if the solvent effect is minimized

Are Students Keeping Up with the E-Book Evolution? Are E-Books Keeping Up with Students' Evolving Needs? Distance Students and E-Book Usage, a Survey

Science.gov (United States)

Brahme, Maria; Gabriel, Lizette

2012-01-01

Electronic books are evolving at a dizzying pace, challenging academic librarians to keep patrons informed about the growing number of features of these resources and their various and varied limitations. It sometimes seems as if students are pleasantly surprised by the ease with which electronic books are accessible as often as they are…