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1

Geothermal hydrogen sulfide removal  

SciTech Connect

UOP Sulfox technology successfully removed 500 ppM hydrogen sulfide from simulated mixed phase geothermal waters. The Sulfox process involves air oxidation of hydrogen sulfide using a fixed catalyst bed. The catalyst activity remained stable throughout the life of the program. The product stream composition was selected by controlling pH; low pH favored elemental sulfur, while high pH favored water soluble sulfate and thiosulfate. Operation with liquid water present assured full catalytic activity. Dissolved salts reduced catalyst activity somewhat. Application of Sulfox technology to geothermal waters resulted in a straightforward process. There were no requirements for auxiliary processes such as a chemical plant. Application of the process to various types of geothermal waters is discussed and plans for a field test pilot plant and a schedule for commercialization are outlined.

Urban, P.

1981-04-01

2

Conversion of Hydrogen Sulfide in Coal Gases to Liquid Elemental Sulfur with Monolithic Catalysts  

SciTech Connect

Removal of hydrogen sulfide (H{sub 2}S) from coal gasifier gas and sulfur recovery are key steps in the development of Department of Energy's (DOE's) advanced power plants that produce electric power and clean transportation fuels with coal and natural gas. These plants will require highly clean coal gas with H{sub 2}S below 1 ppmv and negligible amounts of trace contaminants such as hydrogen chloride, ammonia, alkali, heavy metals, and particulate. The conventional method of sulfur removal and recovery employing amine, Claus, and tail-gas treatment is very expensive. A second generation approach developed under DOE's sponsorship employs hot-gas desulfurization (HGD) using regenerable metal oxide sorbents followed by Direct Sulfur Recovery Process (DSRP). However, this process sequence does not remove trace contaminants and is targeted primarily towards the development of advanced integrated gasification combined cycle (IGCC) plants that produce electricity (not both electricity and transportation fuels). There is an immediate as well as long-term need for the development of cleanup processes that produce highly clean coal gas for next generation power plants. To this end, a novel process is now under development at several research organizations in which the H{sub 2}S in coal gas is directly oxidized to elemental sulfur over a selective catalyst. Such a process is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S In the Single-Step Sulfur Recovery Process (SSRP), the direct oxidation of H{sub 2}S to elemental sulfur in the presence of SO{sub 2} is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S. This direct oxidation process has the potential to produce a super clean coal gas more economically than both conventional amine-based processes and HGD/DSRP. The H{sub 2} and CO components of syngas appear to behave as inert with respect to sulfur formed at the SSRP conditions. One problem in the SSRP process that needs to be eliminated or minimized is COS formation that may occur due to reaction of CO with sulfur formed from the Claus reaction. The objectives of this research are to formulate monolithic catalysts for removal of H{sub 2}S from coal gases and minimum formation of COS with monolithic catalyst supports, {gamma}-alumina wash or carbon coats, and catalytic metals, to develop a catalytic regeneration method for a deactivated monolithic catalyst, to measure kinetics of both direct oxidation of H{sub 2}S to elemental sulfur with SO{sub 2} as an oxidizer and formation of COS in the presence of a simulated coal gas mixture containing H{sub 2}, CO, CO{sub 2}, and moisture, using a monolithic catalyst reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. Experiments on conversion of hydrogen sulfide into elemental sulfur and formation of COS were carried out for the space time range of 130-156 seconds at 120-140 C to formulate catalysts suitable for the removal of H{sub 2}S and COS from coal gases, evaluate removal capabilities of hydrogen sulfide and COS from coal gases with formulated catalysts, and develop an economic regeneration method of deactivated catalysts. Simulated coal gas mixtures consist of 3,300-3,800-ppmv hydrogen sulfide, 1,600-1,900 ppmv sulfur dioxide, 18-21 v% hydrogen, 29-34 v% CO, 8-10 v% CO{sub 2}, 5-18 vol % moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to the reactor are 114-132 SCCM. The temperature of the reactor is controlled in an oven at 120-140 C. The pressure of the reactor is maintained at 116-129 psia. The molar ratio of H{sub 2}S to SO{sub 2} in the monolithic catalyst reactor is

K. C. Kwon

2007-09-30

3

A liquid crystal-based passive badge for personal monitoring of exposure to hydrogen sulfide.  

PubMed

A new liquid crystal (LC)-based passive dosimeter badge for personal monitoring of exposure to hydrogen sulfide (H2S) gas is reported. When a thin film of LC supported on a surface functionalized with lead perchlorate Pb(ClO4)2 (the LC sensor) is exposed to H2S, the orientation of LC molecules in the film changes from perpendicular to parallel. This reorientation induces a change in the appearance of the LC film when viewed between crossed polarizers. A H2S dosimeter was fabricated by pairing a LC sensor with a glass substrate forming a headspace between the two surfaces, to control diffusion of H2S across the LC film. When the dosimeter is exposed to H2S, a bright front appears as a function of exposure time. An algorithm has been developed to correlate this response length and exposure dose. The dosimeters are functionally stable when subjected to extreme temperature and humidity fluctuations, and are immune to a number of potentially interfering chemicals, except mercaptans. These dosimeters detect H2S at 0.2 ppm TWA (8 hr) with ±20% overall accuracy. The dosimeters were used to monitor the personal exposure of personnel working in an oil refinery. The TWA concentrations measured by the LC-based dosimeters correlate strongly with the NIOSH 1063 method that uses a sorbent tube and a pump followed by laboratory analysis. Thus, the LC-based dosimeters can provide a sensitive tool for on-site assessment of personal exposure to H2S in different environments. PMID:24766440

Robinson, Sheila E; Grinwald, Bart A; Bremer, Laura L; Kupcho, Kurt A; Acharya, Bharat R; Owens, Patrick D

2014-11-01

4

Guidance Document Safe Handling of Sulfides and Hydrogen Sulfide  

E-print Network

in Chemistry teaching and research labs. Hydrogen sulfide may be present in natural gas samples (sour gasGuidance Document Safe Handling of Sulfides and Hydrogen Sulfide [This is a brief summary. Read concern would be hydrogen sulfide, whether handling in the pure gaseous form or by generation from various

5

CODE OF PRACTICE HYDROGEN SULFIDE  

E-print Network

­ Hazard Summary Hydrogen sulfide is a colourless, poisonous and flammable gas with the smell of rotten eggs. It can be detected by smell at very low concentrations ranging from 0.01 ­ 0.3 parts per million a person's sense of smell thus make it non-detectable. Hydrogen sulfide is very quickly absorbed

Machel, Hans

6

Modeling hydrogen sulfide emissions across the gas-liquid interface of an anaerobic swine waste treatment storage system  

NASA Astrophysics Data System (ADS)

Hydrogen sulfide (H 2S) is a colorless gas emitted during decomposition of hog manure that produces an offensive "rotten egg" smell and is considered a toxic manure gas. In the southeastern United States, anaerobic waste treatment lagoons are widely used to store and treat hog excreta at commercial hog farms. Hydrogen sulfide is produced as manure decomposes anaerobically, resulting from the mineralization of organic sulfur compounds as well as the reduction of oxidized inorganic sulfur compounds by sulfur-reducing bacteria. The process of H 2S emissions from anaerobic waste treatment lagoons are investigated utilizing a two-film model with three different modeling approaches: Coupled Mass Transfer with Chemical Reactions Model with the assumption (1) pH remains constant in the liquid film (MTCR Model I) and (2) pH may change throughout the liquid film due to diffusion processes that occur within the film (MTCR Model II); and (3) a Mass Transfer Model which neglects chemical reactions (MTNCR Model) in the gas and liquid films. Results of model predictions are consistent with previous works, which show that flux is largely dependent on the physicochemical lagoon properties including sulfide concentration, pH, and lagoon temperature. Air temperature and low wind velocities (e.g., <3.25 m s -1) have negligible impact on flux. Results also indicate that flux values decrease with increased film thickness. The flux was primarily influenced by variations in the liquid film thickness, signifying that the H 2S flux is driven by liquid-phase parameters. Model results were compared with H 2S flux measurements made at a swine waste treatment storage lagoon in North Carolina using a dynamic emission flux chamber system in order to evaluate model accuracy in calculating lagoon H 2S emissions. The MTCR Model II predicted the highest increase in emission rates as aqueous sulfide concentration was increased. The MTNCR Model showed the highest dependence on pH. All three models showed good agreement in diurnal comparison with flux measurements; however, each model significantly over predicted the measured flux rates. The MTNCR Model estimates were closest to experimental values, predicting 3-35 times the actual measured values.

Blunden, Jessica; Aneja, Viney P.; Overton, John H.

7

CODE OF PRACTICE HYDROGEN SULFIDE  

E-print Network

sulfide is a colourless, poisonous and flammable gas with the smell of rotten eggs. It can be detected by smell at very low concentrations ranging from 0.01 ­ 0.3 parts per million. Detection by odour is not reliable because at high concentrations (e.g. 100 ppm), hydrogen sulfide deadens a person's sense of smell

Machel, Hans

8

Molecular Structure of Hydrogen Sulfide  

NSDL National Science Digital Library

Hydrogen Sulfide occurs naturally in crude petroleum, natural gas, volcanic gases, and hot springs. It can also result from bacterial breakdown of organic matter and it is responsible for the smell of rotten eggs. It is also produced by human and animal wastes. Although hydrogen sulfide is a toxic pollutant gas generally occurring in wastewater, it has been used to precipitate metals in wastewater treatment reactors. It has been proposed for stabilization of metals in soils and for formation of metal sulfide "quantum" particles for microelectronics applications.

2003-06-04

9

Solubilization of coal with hydrogen sulfide and carbon monoxide  

SciTech Connect

Conversion of coal to products soluble in common solvents and conversion of coal tar to products of lower molecular weight, effected in liquid or fused reaction medium using a hydrogenating reactant, are carried out employing hydrogen sulfide and carbon monoxide as the sole or major hydrogenating reactant, without need of elemental hydrogen or a hydrogen donor solvent.

Abdel-baset, M.B.; Ratcliffe, C.T.

1980-11-25

10

Tests for Hydrogen Cyanide and Hydrogen Sulfide  

Microsoft Academic Search

A potential source of dangerous concentrations of hydrogen cyanide exists in the plating room of the Machine Shop where open plating baths containing cyanide salts are maintained and where solid cyanide salts are stored. Also the use of hydrogen sulfide in certain steps of the waste disposal process has lead to noticeable and sometimes objectionable concentrations of this gas in

Joy

1949-01-01

11

30 CFR 250.504 - Hydrogen sulfide.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Hydrogen sulfide. 250.504 Section 250.504 Mineral Resources MINERALS MANAGEMENT SERVICE...SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a...

2010-07-01

12

30 CFR 250.604 - Hydrogen sulfide.  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Hydrogen sulfide. 250.604 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a...

2012-07-01

13

30 CFR 250.504 - Hydrogen sulfide.  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Hydrogen sulfide. 250.504 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a...

2011-07-01

14

30 CFR 250.808 - Hydrogen sulfide.  

... 2014-07-01 false Hydrogen sulfide. 250.808 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production...

2014-07-01

15

30 CFR 250.808 - Hydrogen sulfide.  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Hydrogen sulfide. 250.808 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production...

2011-07-01

16

30 CFR 250.604 - Hydrogen sulfide.  

... 2014-07-01 false Hydrogen sulfide. 250.604 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a...

2014-07-01

17

30 CFR 250.808 - Hydrogen sulfide.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Hydrogen sulfide. 250.808 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production...

2010-07-01

18

30 CFR 250.604 - Hydrogen sulfide.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Hydrogen sulfide. 250.604 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a...

2013-07-01

19

30 CFR 250.604 - Hydrogen sulfide.  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Hydrogen sulfide. 250.604 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a...

2011-07-01

20

30 CFR 250.504 - Hydrogen sulfide.  

... 2014-07-01 false Hydrogen sulfide. 250.504 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a...

2014-07-01

21

30 CFR 250.808 - Hydrogen sulfide.  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Hydrogen sulfide. 250.808 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production...

2012-07-01

22

30 CFR 250.808 - Hydrogen sulfide.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Hydrogen sulfide. 250.808 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production...

2013-07-01

23

30 CFR 250.504 - Hydrogen sulfide.  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Hydrogen sulfide. 250.504 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a...

2012-07-01

24

30 CFR 250.504 - Hydrogen sulfide.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Hydrogen sulfide. 250.504 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a...

2013-07-01

25

30 CFR 250.604 - Hydrogen sulfide.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Hydrogen sulfide. 250.604 Section...INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN...CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a...

2010-07-01

26

Process for treating gas containing hydrogen sulfide  

Microsoft Academic Search

A process is described for treating a hydrogen sulfide-containing gas in a closed loop system wherein said gas is passed through and absorbed by an alkaline aqueous absorbent containing an alkali carbonate and an oxidation catalyst. The solution containing the dissolved hydrogen sulfide is oxidized with an oxygen-containing gas to convert the absorbed hydrogen sulfide into elementary sulfur and sulfur

H. Tsuruta; Y. Hiwatashi; T. Hirabayashi; S. Kumata

1976-01-01

27

Raman Spectra of Hydrogen and Deuterium Sulfides in the Gas, Liquid and Solid States  

Microsoft Academic Search

Raman spectra have been obtained for H2S and D2S as gas, liquid and solid. Only one frequency has been obtained in the gas and liquid although three are permitted by the selection principles. In the solids, a single line and a close doublet have been obtained. With the available infra-red and Raman data, it is not possible to make quantitative

George M. Murphy; John E. Vance

1938-01-01

28

Suicide by hydrogen sulfide inhalation.  

PubMed

The authors report a case of suicide by hydrogen sulfide in Australia. A young woman was located in a car wearing protective eyewear. A tub of foamy yellow substance and a quantity of hydrochloric acid and lime sulfur were also located in the rear of the vehicle. Morphological findings at autopsy were nonspecific. Toxicologic analysis of a specimen of leg blood detected elevated levels of methemoglobin. If Australia follows a similar trend to Japan and the United States, it is possible that incidences of such cases will rise, probably because of Internet dissemination. From a public health perspective, emergency service providers and forensic case workers should be aware of the potential hazards to themselves and others when dealing with such cases. PMID:23361075

Bott, Eleanor; Dodd, Malcolm

2013-03-01

29

Hydrogen sulfide and the liver.  

PubMed

Hydrogen sulfide (H2S) is a gasotransmitter that regulates numerous physiological and pathophysiological processes in our body. Enzymatic production of H2S is catalyzed by cystathionine ?-lyase (CSE), cystathionine ?-synthase (CBS), and 3-mercaptopyruvate sulfurtransferase (MST). All these three enzymes present in the liver and via H2S production regulate liver functions. The liver is the hub for metabolism of glucose and lipids, and maintains the level of circulatory lipids through lipoprotein metabolism. Hepatic H2S metabolism affects glucose metabolism, insulin sensitivity, lipoprotein synthesis, mitochondrial biogenetics and biogenesis. Malfunction of hepatic H2S metabolism may be involved in many liver diseases, such as hepatic fibrosis and hepatic cirrhosis. PMID:24582857

Mani, Sarathi; Cao, Wei; Wu, Lingyun; Wang, Rui

2014-09-15

30

Health effects of hydrogen sulfide  

SciTech Connect

Hydrogen sulfide is a product of a number of natural processes, such as bacterial decomposition of organic matter and geothermal activity. It is a component of crude petroleum, natural gas and volcanic gases. Although high concentrations of H{sub 2}S are acutely toxic, exposure to low concentrations is not generally associated with adverse health effects. Epidemiological studies overall have not demonstrated significant health effects or increased risk of cancer among workers or residents exposed to low levels of H{sub 2}S and other reduced sulfur gases, and based on known mechanisms of H{sub 2}S toxicity, any such effects are unlikely. However, some individuals have associated minor, subjective-type physical symptoms with exposure to low levels of reduced sulfur gases. The potential mechanism(s) for, or significance of, these responses is not well understood.

Tatum, V.L. [National Council of the Paper Industry for Air and Stream Improvement, Research Triangle Park, NC (United States)

1996-12-31

31

Liquid Hydrogen  

Microsoft Academic Search

THE letter of W. Hampson, which appears in your issue of May 26, can only mean by implication to charge me with having utilised without acknowledgment an idea of his, conveyed through a third party, in my paper on the liquid hydrogen jet, published in 1895. Such a suggestion is absolutely without any foundation in fact. My results would have

J. Dewar

1898-01-01

32

Ridding Groundwater of Hydrogen Sulfide. Part 1.  

ERIC Educational Resources Information Center

This article is the first in a series reviewing the problems associated with hydrogen sulfide in drinking water sources. Discussion centers on identification of a cost-effective balance between aeration and chlorination treatment operations. (AS)

Lochrane, Thomas G.

1979-01-01

33

Removal of hydrogen sulfide from gas streams  

SciTech Connect

Hydrogen sulfide is removed from a gas stream by contacting the gas stream with an aqueous alkanolamine solution in a high surface area rotor. The solution is subjected to an acceleration greater than that due to gravity. 16 claims.

Toms, D.J.

1983-10-03

34

Hydrogen and sulfur recovery from hydrogen sulfide wastes  

DOEpatents

A process for generating hydrogen and elemental sulfur from hydrogen sulfide waste in which the hydrogen sulfide is associated under plasma conditions and a portion of the hydrogen output is used in a catalytic reduction unit to convert sulfur-containing impurities to hydrogen sulfide for recycle, the process also including the addition of an ionizing gas such as argon to initiate the plasma reaction at lower energy, a preheater for the input to the reactor and an internal adjustable choke in the reactor for enhanced coupling with the microwave energy input.

Harkness, John B. L. (Naperville, IL); Gorski, Anthony J. (Woodridge, IL); Daniels, Edward J. (Oak Lawn, IL)

1993-01-01

35

Hydrogen and Sulfur Production from Hydrogen Sulfide Wastes  

E-print Network

, this novel process recovers both hydrogen and sulfur. The plasma process involves dissociating hydrogen sulfide in a "nonequilibrium" plasma in a microwave or radio-frequency reactor. After the dissociation process, sulfur is condensed and sold just...

Harkness, J.; Doctor, R. D.

36

Terahertz spectroscopy of hydrogen sulfide  

NASA Astrophysics Data System (ADS)

Pure rotational transitions of hydrogen sulfide (H2S) in its ground and first excited vibrational states have been recorded at room temperature. The spectrum comprises an average of 1020 scans at 0.005 cm-1 resolution recorded in the region 45-360 cm-1 (1.4 to 10.5 THz) with a globar continuum source using a Fourier transform spectrometer located at the AILES beamline of the SOLEIL synchrotron. Over 2400 rotational lines have been detected belonging to ground vibrational state transitions of the four isotopologues H232S, H233S, H234S, and H236S observed in natural abundance. 65% of these lines are recorded and assigned for the first time, sampling levels as high as J=26 and Ka=17 for H232S. 320 pure rotational transitions of H232S in its first excited bending vibrational state are recorded and analysed for the first time and 86 transitions for H234S, where some of these transitions belong to new experimental energy levels. Rotational constants have been fitted for all the isotopologues in both vibrational states using a standard effective Hamiltonian approach. Comprehensive comparisons are made with previously available data as well as the data available in HITRAN, CDMS, and JPL databases. The 91 transitions assigned to H236S give the first proper characterization of its pure rotational spectrum.

Azzam, Ala'a. A. A.; Yurchenko, Sergei N.; Tennyson, Jonathan; Martin-Drumel, Marie-Aline; Pirali, Olivier

2013-11-01

37

Hydrogen sulfide and translational medicine  

PubMed Central

Hydrogen sulfide (H2S) along with carbon monoxide and nitric oxide is an important signaling molecule that has undergone large numbers of fundamental investigations. H2S is involved in various physiological activities associated with the regulation of homeostasis, vascular contractility, pro- and anti-inflammatory activities, as well as pro- and anti-apoptotic activities etc. However, the actions of H2S are influenced by its concentration, reaction time, and cell/disease types. Therefore, H2S is a signaling molecule without definite effect. The use of existing H2S donors is limited because of the instant release and short lifetime of H2S. Thus, translational medicine involving the sustained and controlled release of H2S is of great value for both scientific and clinical uses. H2S donation can be manipulated by different ways, including where H2S is given, how H2S is donated, or the specific structures of H2S-releasing drugs and H2S donor molecules. This review briefly summarizes recent progress in research on the physiological and pathological functions of H2S and H2S-releasing drugs, and suggests hope for future investigations. PMID:24096643

Guo, Wei; Cheng, Ze-yu; Zhu, Yi-zhun

2013-01-01

38

Hydrogen sulfide effects on stomatal apertures.  

PubMed

Hydrogen sulfide (H(2)S) has recently been reported to be a signaling molecule in plants. It has been well established that is has such roles in animals and it has been suggested that it is included into the group of gasotransmitters. We have recently shown that hydrogen sulfide causes stomatal opening in the model plant Arabidopsis thaliana. H(2)S can be supplied to the plant tissues from donors such as sodium hydrosulfide (NaSH) or more recently from slow release H(2)S donor molecules such as GYY4137. Both give similar effects, that is, they cause stomatal opening. Furthermore both H(2)S donors reduced the accumulation of nitric oxide (NO) induced by abscisic acid (ABA) treatment of leaf tissues. Here similar work has been repeated in a crop plant, Capsium anuum, and similar data has been obtained, suggesting that such effects of hydrogen sulfide on plants is not confined to model species. PMID:21904118

Lisjak, Miroslav; Tekli?, Tihana; Wilson, Ian D; Wood, Mark; Whiteman, Matt; Hancock, John T

2011-10-01

39

Cardioprotective effects of hydrogen sulfide  

PubMed Central

The gaseous mediator hydrogen sulfide (H2S) is synthesized mainly by cystathionine gamma-lyase in the heart and plays a role in the regulation of cardiovascular homeostasis. Here we first overview the state of the art in the literature on the cardioprotective effects of H2S in various models of cardiac injury. Subsequently, we present original data showing the beneficial effects of parenteral administration of a donor of H2S on myocardial and endothelial function during reperfusion in a canine experimental model of cardiopulmonary bypass. Overview of the literature demonstrates that various formulations of H2S exert cardioprotective effects in cultured cells, isolated hearts and various rodent and large animal models of regional or global myocardial ischemia and heart failure. In addition, the production of H2S plays a role in myocardial pre- and post-conditioning responses. The pathways implicated in the cardioprotective action of H2S are multiple and involve KATP channels, regulation of mitochondrial respiration, and regulation of cytoprotective genes such as Nrf-2. In the experimental part of the current article, we demonstrate the cardioprotective effects of H2S in a canine model of cardiopulmonary bypass surgery. Anesthetized dogs were subjected hypothermic cardiopulmonary bypass with 60 minutes of hypothermic cardiac arrest in the presence of either saline (control, n=8), or H2S infusion (1 mg/kg/h for 2 h). Left ventricular hemodynamic variables (via combined pressure-volume-conductance catheter) as well as coronary blood flow, endothelium-dependent vasodilatation to acetylcholine and endothelium-independent vasodilatation to sodium nitroprusside were measured at baseline and after 60 minutes of reperfusion. Ex vivo vascular function and high-energy phosphate contents were also measured. H2S led to a significantly better recovery of preload recruitable stroke work (p<0.05) after 60 minutes of reperfusion. Coronary blood flow was also significantly higher in the H2S group (p<0.05). While the vasodilatory response to sodium nitroprusside was similar in both groups, acetylcholine resulted in a significantly higher increase in coronary blood flow in the H2S-treated group (p<0.05) both in vivo and ex vivo. Furthermore, high-energy phosphate contents were better preserved in the H2S group. Additionally, the cytoprotective effects of H2S were confirmed also using in vitro cell culture experiments in H9c2 cardiac myocytes exposed to hypoxia and reoxygenation or to the cytotoxic oxidant hydrogen peroxide. Thus, therapeutic administration of H2S exerts cardioprotective effects in a variety of experimental models, including a significant improvement of the recovery of myocardial and endothelial function in a canine model of cardiopulmonary bypass with hypothermic cardiac arrest. PMID:21094267

Szabo, Gabor; Veres, Gabor; Radovits, Tamas; Gero, Domokos; Modis, Katalin; Miesel-Groschel, Christiane; Horkay, Ferenc; Karck, Matthias; Szabo, Csaba

2010-01-01

40

Hydrogen and sulfur production from hydrogen sulfide wastes  

SciTech Connect

A new hydrogen sulfide waste-treatment process that uses microwave plasma-chemical technology is currently under development in the Soviet Union and in the United States. Whereas the present waste treatment process only recovers sulfur at best, this novel process recovers both hydrogen and sulfur. The plasma process involves dissociating hydrogen sulfide in a ``nonequilibrium`` plasma in a microwave or radio-frequency reactor. After the dissociation process, sulfur is condensed and sold just as is currently done. The remaining gases are purified and separated into streams containing the product hydrogen, the hydrogen sulfide to be recycled to the plasma reactor, and the process purge containing carbon dioxide and water. This process has particular implications for the petroleum refining industry, in which hydrogen is a widely used reagent and must be produced from increasingly scarce hydrocarbon resources. The modular nature of the new process may also offer economic advantages over small-scale waste treatment technologies widely used in the natural-gas industry. Laboratory-scale experiments with pure hydrogen sulfide indicate that conversions exceeding 90% are possible with appropriate reactor design and that the energy required to dissociate hydrogen sulfide is low enough for the plasma process to be economically competitive. In addition, the experiments show that typical refinery acid-gas streams are compatible with the plasma process and that all by-products can be treated with existing technology.

Harkness, J.B.L.; Doctor, R.D.

1993-03-01

41

Hydrogen and sulfur production from hydrogen sulfide wastes  

SciTech Connect

A new hydrogen sulfide waste-treatment process that uses microwave plasma-chemical technology is currently under development in the Soviet Union and in the United States. Whereas the present waste treatment process only recovers sulfur at best, this novel process recovers both hydrogen and sulfur. The plasma process involves dissociating hydrogen sulfide in a nonequilibrium'' plasma in a microwave or radio-frequency reactor. After the dissociation process, sulfur is condensed and sold just as is currently done. The remaining gases are purified and separated into streams containing the product hydrogen, the hydrogen sulfide to be recycled to the plasma reactor, and the process purge containing carbon dioxide and water. This process has particular implications for the petroleum refining industry, in which hydrogen is a widely used reagent and must be produced from increasingly scarce hydrocarbon resources. The modular nature of the new process may also offer economic advantages over small-scale waste treatment technologies widely used in the natural-gas industry. Laboratory-scale experiments with pure hydrogen sulfide indicate that conversions exceeding 90% are possible with appropriate reactor design and that the energy required to dissociate hydrogen sulfide is low enough for the plasma process to be economically competitive. In addition, the experiments show that typical refinery acid-gas streams are compatible with the plasma process and that all by-products can be treated with existing technology.

Harkness, J.B.L.; Doctor, R.D.

1993-01-01

42

Comparison of Hydrogen Sulfide Analysis Techniques  

ERIC Educational Resources Information Center

A summary and critique of common methods of hydrogen sulfide analysis is presented. Procedures described are: reflectance from silver plates and lead acetate-coated tiles, lead acetate and mercuric chloride paper tapes, sodium nitroprusside and methylene blue wet chemical methods, infrared spectrophotometry, and gas chromatography. (BL)

Bethea, Robert M.

1973-01-01

43

Wheat straw cover for reducing ammonia and hydrogen sulfide emissions from dairy manure storage  

SciTech Connect

Analysis of the use of a wheat straw cover for reducing ammonia and hydrogen sulfide emissions from liquid manure was conducted in both a laboratory and a pilot system. Two straw covers with different thicknesses (5 cm and 10 cm) were evaluated for their effectiveness in reducing odorous gas emissions. The rates of ammonia and hydrogen sulfide emissions from the treatments were monitored; concentrations of ammonia, dissolved sulfide, chemical oxygen demand (COD), and pH of the liquid manure were measured. Additionally, the overall mass transfer coefficients of ammonia and hydrogen sulfide were calculated for the conditions of the experiment. The results demonstrated that both the 5-cm and 10-cm straw covers were effective in reducing ammonia and hydrogen sulfide emissions from manure storage. In the laboratory tests, when a crust formed on the manure surface within three to four weeks after the straw application, ammonia emissions were reduced by up to 95%. A similar trend was observed in the pilot experiments in the field. Hydrogen sulfide emissions were suppressed by 95% with the wheat straw cover. The mass transfer coefficients of hydrogen sulfide with the straw covers were significantly lower than those of the control, which indicated the effectiveness of a straw cover as a physical barrier for reducing hydrogen sulfide emissions. Reduced pH and decreased ammonia that biological reactions might also be a factor contributing to the emission reductions.

Xue, S.K.; Hermanson, R.E.

1999-08-01

44

Method for direct production of carbon disulfide and hydrogen from hydrocarbons and hydrogen sulfide feedstock  

SciTech Connect

A method for converting hydrocarbons and hydrogen sulfide to carbon disulfide and hydrogen is provided comprising contacting the hydrocarbons and hydrogen sulfide to a bi-functional catalyst residing in a controlled atmosphere for a time and at a temperature sufficient to produce carbon disulfide and hydrogen. Also provided is a catalyst for converting carbon sulfides and hydrogen sulfides to gasoline range hydrocarbons comprising a mixture containing a zeolite catalyst and a hydrogenating catalyst.

Miao, Frank Q.; Erekson, Erek James

1998-12-01

45

Hydrogen attack - Influence of hydrogen sulfide. [on carbon steel  

NASA Technical Reports Server (NTRS)

An experimental study is conducted on 12.5-mm-thick SAE 1020 steel (plain carbon steel) plate to assess hydrogen attack at room temperature after specimen exposure at 525 C to hydrogen and a blend of hydrogen sulfide and hydrogen at a pressure of 3.5 MN/sq m for exposure times up to 240 hr. The results are discussed in terms of tensile properties, fissure formation, and surface scales. It is shown that hydrogen attack from a high-purity hydrogen environment is severe, with the formation of numerous methane fissures and bubbles along with a significant reduction in the room-temperature tensile yield and ultimate strengths. However, no hydrogen attack is observed in the hydrogen/hydrogen sulfide blend environment, i.e. no fissure or bubble formation occurred and the room-temperature tensile properties remained unchanged. It is suggested that the observed porous discontinuous scale of FeS acts as a barrier to hydrogen entry, thus reducing its effective equilibrium solubility in the iron lattice. Therefore, hydrogen attack should not occur in pressure-vessel steels used in many coal gasification processes.

Eliezer, D.; Nelson, H. G.

1978-01-01

46

PRODUCTION OF HYDROGEN BY SUPERADIABATIC DECOMPOSITION OF HYDROGEN SULFIDE  

Microsoft Academic Search

The Gas Technology Institute, in collaboration with the University of Illinois at Chicago and industrial partners, including UOP, has been developing an innovative noncatalytic, thermochemical process for the production of hydrogen and elemental sulfur from hydrogen sulfide in H2S-containing waste gases. The key feature of this process is the superadiabatic reactor, where partial oxidation of H2S in the feed gas

Rachid B. Slimane; Francis S. Lau; Remon J. Dihu; Mark Khinkis

47

Removal of hydrogen sulfide, benzene and toluene by a fluidized bed bioreactor  

Microsoft Academic Search

The dominant off gases from publicly owned treatment works include hydrogen sulfide, benzene, and toluene. In this research,\\u000a hydrogen sulfide oxidized byBacillus cereus, and benzene with toluene were removed by VOC-degrading microbial consortium. The optimum operating condition of the fluidized\\u000a bed bioreactor including both microorganisms was 30 ‡C, pH 6–8, and 150 cm of liquid bed height. The critical loading

Kwang Joong Oh; Ki Chul Cho; Young Hean Choung; Suk Kyong Park; Sung Ki Cho; Donguk Kim

2006-01-01

48

Hydrogen sulfide inhibits the renal fibrosis of obstructive nephropathy  

PubMed Central

Hydrogen sulfide has recently been found decreased in chronic kidney disease. Here we determined the effect and underlying mechanisms of hydrogen sulfide on a rat model of unilateral ureteral obstruction. Compared with normal rats, obstructive injury decreased the plasma hydrogen sulfide level. Cystathionine-?-synthase, a hydrogen sulfide-producing enzyme, was dramatically reduced in the ureteral obstructed kidney, but another enzyme cystathionine-?-lyase was increased. A hydrogen sulfide donor (sodium hydrogen sulfide) inhibited renal fibrosis by attenuating the production of collagen, extracellular matrix, and the expression of ?-smooth muscle actin. Meanwhile, the infiltration of macrophages and the expression of inflammatory cytokines including interleukin-1?, tumor necrosis factor-?, and monocyte chemoattractant protein-1 in the kidney were also decreased. In cultured kidney fibroblasts, a hydrogen sulfide donor inhibited the cell proliferation by reducing DNA synthesis and downregulating the expressions of proliferation-related proteins including proliferating cell nuclear antigen and c-Myc. Further, the hydrogen sulfide donor blocked the differentiation of quiescent renal fibroblasts to myofibroblasts by inhibiting the transforming growth factor-?1-Smad and mitogen-activated protein kinase signaling pathways. Thus, low doses of hydrogen sulfide or its releasing compounds may have therapeutic potentials in treating chronic kidney disease. PMID:24284510

Song, Kai; Wang, Fen; Li, Qian; Shi, Yong-Bing; Zheng, Hui-Fen; Peng, Hanjing; Shen, Hua-Ying; Liu, Chun-Feng; Hu, Li-Fang

2014-01-01

49

High temperature regenerable hydrogen sulfide removal agents  

DOEpatents

A system for high temperature desulfurization of coal-derived gases using regenerable sorbents. One sorbent is stannic oxide (tin oxide, SnO.sub.2), the other sorbent is a metal oxide or mixed metal oxide such as zinc ferrite (ZnFe.sub.2 O.sub.4). Certain otherwise undesirable by-products, including hydrogen sulfide (H.sub.2 S) and sulfur dioxide (SO.sub.2) are reused by the system, and elemental sulfur is produced in the regeneration reaction. A system for refabricating the sorbent pellets is also described.

Copeland, Robert J. (Wheat Ridge, CO)

1993-01-01

50

Amorphous molybdenum sulfides as hydrogen evolution catalysts.  

PubMed

Providing energy for a population projected to reach 9 billion people within the middle of this century is one of the most pressing societal issues. Burning fossil fuels at a rate and scale that satisfy our near-term demand will irreversibly damage the living environment. Among the various sources of alternative and CO2-emission-free energies, the sun is the only source that is capable of providing enough energy for the whole world. Sunlight energy, however, is intermittent and requires an efficient storage mechanism. Sunlight-driven water splitting to make hydrogen is widely considered as one of the most attractive methods for solar energy storage. Water splitting needs a hydrogen evolution catalyst to accelerate the rate of hydrogen production and to lower the energy loss in this process. Precious metals such as Pt are superior catalysts, but they are too expensive and scarce for large-scale applications. In this Account, we summarize our recent research on the preparation, characterization, and application of amorphous molybdenum sulfide catalysts for the hydrogen evolution reaction. The catalysts can be synthesized by electrochemical deposition under ambient conditions from readily available and inexpensive precursors. The catalytic activity is among the highest for nonprecious catalysts. For example, at a loading of 0.2 mg/cm(2), the optimal catalyst delivers a current density of 10 mA/cm(2) at an overpotential of 160 mV. The growth mechanism of the electrochemically deposited film catalysts was revealed by an electrochemical quartz microcrystal balance study. While different electrochemical deposition methods produce films with different initial compositions, the active catalysts are the same and are identified as a "MoS(2+x)" species. The activity of the film catalysts can be further promoted by divalent Fe, Co, and Ni ions, and the origins of the promotional effects have been probed. Highly active amorphous molybdenum sulfide particles can also be prepared from simple wet-chemical routes. Electron transport is sometimes slow in the particle catalysts, and an impedance model has been established to identify this slow electron transport. Finally, the amorphous molybdenum sulfide film catalyst has been integrated onto a copper(I) oxide photocathode for photoelectrochemical hydrogen evolution. The conformal catalyst efficiently extracts the excited electrons to give an impressive photocurrent density of -5.7 mA/cm(2) at 0 V vs RHE. The catalyst also confers good stability. PMID:25065612

Morales-Guio, Carlos G; Hu, Xile

2014-08-19

51

Chromium(VI) Reduction by Hydrogen Sulfide in Aqueous  

E-print Network

stoichiometry, kinetics, and mechanism for Cr(VI) reduction by hydrogen sulfide in the aqueous phase. Batch-), intramolecular electron transfer to form Cr(IV) species, and subsequent fast reactions leading to Cr to catalysis by dissolved and surface-bound metals (14, 28-30). Hydrogen sulfide is one of the strongest

Deng, Baolin

52

Oxidation of hydrogen sulfide by human liver mitochondria.  

PubMed

Hydrogen sulfide (H2S) is the third gasotransmitter discovered. Sulfide shares with the two others (NO and CO) the same inhibiting properties towards mitochondrial respiration. However, in contrast with NO or CO, sulfide at concentrations lower than the toxic (?M) level is an hydrogen donor and a substrate for mitochondrial respiration. This is due to the activity of a sulfide quinone reductase found in a large majority of mitochondria. An ongoing study of the metabolic state of liver in obese patients allowed us to evaluate the sulfide oxidation capacity with twelve preparations of human liver mitochondria. The results indicate relatively high rates of sulfide oxidation with a large variability between individuals. These observations made with isolated mitochondria appear in agreement with the main characteristics of sulfide oxidation as established before with the help of cellular models. PMID:24928562

Helmy, Nada; Prip-Buus, Carina; Vons, Corinne; Lenoir, Véronique; Abou-Hamdan, Abbas; Guedouari-Bounihi, Hala; Lombès, Anne; Bouillaud, Frédéric

2014-09-15

53

Remediation of sulfidic wastewater by catalytic oxidation with hydrogen peroxide.  

PubMed

Oxidation of sulfide in aqueous solution by hydrogen peroxide was investigated in the presence of hydrated ferric oxide catalyst. The ferric oxide catalyst was synthesized by sol gel technique from ferric chloride and ammonia. The synthesized catalyst was characterized by Fourier transform infrared spectroscopy, X-Ray diffraction analysis, scanning electrom microscope and energy dispersive X-ray analysis. The catalyst was quite effective in oxidizing the sulfide by hydrogen peroxide. The effects of sulfide concentration, catalyst loading, H2O2 dosing and temperature on the kinetics of sulfide oxidation were investigated. Kinetic equations and activation energies for the catalytic oxidation reaction were calculated based on the experimental results. PMID:20131606

Ahmad, Naveed; Maitra, Saikat; Dutta, Binay Kanti; Ahmad, Farooq

2009-01-01

54

Hydrogen sulfide and the metabolic syndrome.  

PubMed

The metabolic syndrome is a group of abnormalities including obesity, high blood pressure, hyperinsulinemia, high blood glucose levels and hyperlipidemia that together greatly increase the risk of developing cardiovascular disease and Type 2 diabetes. Hydrogen sulfide (H(2)S) is a vasodilatory gasotransmitter mediator in the cardiovascular system, proposed as an endothelium-derived relaxing factor. A lack of H(2)S and its synthesizing enzyme, cystathionine ?-lyase, in the vasculature causes hypertension, whereas an increase in the pancreas reduces insulin secretion. Thus, research is making inroads to determine whether H(2)S is involved in the pathogenesis of the metabolic syndrome. Several laboratories are synthesizing and testing clinically used drugs that release H(2)S. Some of these compounds are being tested for effectiveness in the metabolic syndrome. PMID:22115349

Desai, Kaushik M; Chang, Tuanjie; Untereiner, Ashley; Wu, Lingyun

2011-01-01

55

[Hyperbaric oxygen for hydrogen sulfide poisoning].  

PubMed

Hydrogen sulfide (H2S) is a toxic gas produced in decaying substances containing organic sulfur. Exposure to the gas causes severe disturbances in the central nervous and respiratory systems. The mechanism of toxicity is disruption of the electron transport chain in mitochondria, resulting in intracellular hypoxia. Treatment of H2S poisoning includes mechanical ventilation with 100% oxygen and immediate administration of sodium nitrate. Treatment with hyperbaric oxygen (HBO) has been studied in animal models, and has also been used in a number of patients. However, the clinical effectiveness of this mode of therapy has not been clearly proven. Having recently treated a case of H2S poisoning, we suggest HBO to reduce mortality. PMID:7843654

Goldenberg, I; Shoshani, O; Mushkat, Y; Bentur, Y; Melamed, Y; Shupak, A

1994-11-01

56

Hydrogen sulfide exposure in an adult male  

PubMed Central

Hydrogen sulfide (H2S) is responsible for many incidents of occupational toxic exposure, especially in the petroleum industry. The clinical effects of H2S depend on its concentration and the duration of exposure. H2S is immediately fatal when concentrations are over 500-1000 parts per million (ppm) but exposure to lower concentrations, such as 10-500 ppm, can cause various respiratory symptoms that range from rhinitis to acute respiratory failure. H2S may also affect multiple organs, causing temporary or permanent derangements in the nervous, cardiovascular, renal, hepatic, and hematological systems. We present a case of occupational exposure to H2S leading to multi-organ involvement, acute respiratory failure, organizing pneumonia, and shock resembling acute sepsis. The patient also developed mild obstructive and restrictive pulmonary disease and peripheral neuropathy. PMID:20103963

Doujaiji, Bassam; Al-Tawfiq, Jaffar A.

2010-01-01

57

NEAR-CONTINUOUS MEASUREMENT OF HYDROGEN SULFIDE AND CARBONYL SULFIDE BY AN AUTOMATIC GAS CHROMATOGRAPH  

EPA Science Inventory

An automatic gas chromatograph with a flame photometric detector that samples and analyzes hydrogen sulfide and carbonyl sulfide at 30-s intervals is described. Temperature programming was used to elute trace amounts of carbon disulfide present in each injection from a Supelpak-S...

58

Carbonyl Sulfide Removal with Compost and Wood Chip Biofilters, and in the Presence of Hydrogen Sulfide  

Microsoft Academic Search

Carbonyl sulfide (COS) is an odor-causing compound and hazardous air pollutant emitted frequently from wastewater treatment facilities and chemical and primary metals industries. This study examined the effectiveness of biofiltration in removing COS. Specific objectives were to compare COS removal efficiency for various biofilter media; to determine whether hydrogen sulfide (H2S), which is frequently produced along with COS under anaerobic

Melanie L. Sattler; Divya R. Garrepalli; Chandraprakash S. Nawal; Hulda Winnes; Erik Fridell; Morton Barlaz; Jeff Chanton; Roger Green; Junyu Zheng; Wenwei Che; Xuemei Wang; Peter Louie; Liuju Zhong; Elizabeth Vega; Douglas Lowenthal; Hugo Ruiz; Elizabeth Reyes; John Watson; Judith Chow; Mar Viana; Xavier Querol; Andres Alastuey; Mark Gibson; Mathew Heal; David Bache; Andrew Hursthouse; Iain Beverland; Susanne Craig; Colin Clark; Mike Jackson; Nicholas Nussbaum; Dongzi Zhu; Hampden Kuhns; Claudio Mazzoleni; M.-C. Chang; Hans ller; David Sodeman; Sebastian Uppapalli; Daniel Burgard; Melissa Provinsal; Lien-Te Hsieh; Ya-Fen Wang; Gia-Hao Kuo; Lin-Chi Wang; Guo-Ping Chang-Chien; Pedro Sanhueza; Monica Torreblanca; Luis Diaz-Robles; L. Schiappacasse; Maria Silva; Teresa Astete

2009-01-01

59

Hydrogen sulfide: environmental factor or signalling molecule?  

PubMed

Hydrogen sulfide (H?S) has traditionally been thought of as a phytotoxin, having deleterious effects on the plant growth and survival. It is now recognized that plants have enzymes which generate H?S, cysteine desulfhydrase, and remove it, O-acetylserine lyase. Therefore, it has been suggested that H?S is considered as a signalling molecule, alongside small reactive compounds such as hydrogen peroxide (H?O?) and nitric oxide (NO). Exposure of plants to low of H?S, for example from H?S donors, is revealing that many physiological effects are seen. H?S seems to have effects on stomatal apertures. Intracellular effects include increases in glutathione levels, alterations of enzyme activities and influences on NO and H?O? metabolism. Work in animals has shown that H?S may have direct effects on thiol modifications of cysteine groups, work that will no doubt inform future studies in plants. It appears therefore, that instead of thinking of H?S as a phytotoxin, it needs to be considered as a signalling molecule that interacts with reactive oxygen species and NO metabolism, as well as having direct effects on the activity of proteins. The future may see H?S being used to modulate plant physiology in the field or to protect crops from postharvest spoilage. PMID:23347018

Lisjak, Miroslav; Teklic, Tihana; Wilson, Ian D; Whiteman, Matthew; Hancock, John T

2013-09-01

60

An Experiment in Autotrophic Fermentation: Microbial Oxidation of Hydrogen Sulfide.  

ERIC Educational Resources Information Center

Described is an experiment which uses an autotrophic bacterium to anaerobically oxidize hydrogen sulfide to sulfate in a batch-stirred tank reactor. Discusses background information, experimental procedure, and sample results of this activity. (CW)

Sublette, Kerry L.

1989-01-01

61

Sulfides in the Anaerobic Environment: The Determination of Hydrogen Sulfide and Acid-Soluble Metallic Sulfides in Sea-Floor Sediment  

NASA Astrophysics Data System (ADS)

A procedure for the determination of hydrogen sulfide and acid-soluble metallic sulfides in sea floor sediment has been developed and tested as part of a laboratory course in analytical and environmental chemistry. The procedure includes (i) anaerobic sampling of sediment, (ii) a volatilization method, which discriminates between hydrogen sulfide and acid-soluble metallic sulfides in the sediment, and (iii) a quantitative determination of these sulfide components using an ion-selective electrode approach. The paper describes all experimental details and gives a brief summary of sulfide generation processes in sea-floor sediments, underlining the importance of sulfides in anaerobic environments. Representative results obtained during the laboratory course are discussed.

Christensen, Joan Kai; Høyer, Boy; Kryger, Lars; Pind, Niels; Kong, Lee Sing

1998-12-01

62

Hydrogen Sulfide in Drinking Water: Causes and Treatment Alternatives  

E-print Network

. The process oxidizes hydrogen sulfide into sulfate; iron and manganese form precipitates that are filtered out (Fig. 3). Manganese greensand filters must be recharged with a solution of potas- sium permanganate when the oxygen is depleted. This process is very.... The process oxidizes hydrogen sulfide into sulfate; iron and manganese form precipitates that are filtered out (Fig. 3). Manganese greensand filters must be recharged with a solution of potas- sium permanganate when the oxygen is depleted. This process is very...

McFarland, Mark L.; Provin, Tony

1999-06-15

63

Oxygen-hydrogen sulfide intermediate layer of the Black Sea  

SciTech Connect

Spatial and vertical boundaries were studied for the oxygen-hydrogen sulfide intermediate layer in the Black Sea. The wind has a great influence on the thermohaline structure of the Danube coastal waters. It causes strong out-and-influx processes and up-welling of hydrogen sulfide waters of the intermediate layer in the north-western part of the Black Sea, which is supposed to be one of the reasons for the ecological equilibrium disturbance in this region.

Timoshchuk, V.I.; Risik, N.S.

1980-01-01

64

The partitioning of hydrogen sulfide in the condensers of Geysers Unit 15  

Microsoft Academic Search

Geysers Unit 15 was the first of the geothermal units equipped with surface condensers to go on line at The Geysers power plant of the Pacific Gas and Electric Company. Units 1 through 12 have contact condensers. The switch to surface condensers was motivated by considerations of hydrogen sulfide mission abatement. In the contact condensers, there is a large liquid-to-vapor

O. Weres

1982-01-01

65

Organization of the human mitochondrial hydrogen sulfide oxidation pathway.  

PubMed

Sulfide oxidation is expected to play an important role in cellular switching between low steady-state intracellular hydrogen sulfide levels and the higher concentrations where the physiological effects are elicited. Yet despite its significance, fundamental questions regarding how the sulfide oxidation pathway is wired remain unanswered, and competing proposals exist that diverge at the very first step catalyzed by sulfide quinone oxidoreductase (SQR). We demonstrate that, in addition to sulfite, glutathione functions as a persulfide acceptor for human SQR and that rhodanese preferentially synthesizes rather than utilizes thiosulfate. The kinetic behavior of these enzymes provides compelling evidence for the flow of sulfide via SQR to glutathione persulfide, which is then partitioned to thiosulfate or sulfite. Kinetic simulations at physiologically relevant metabolite concentrations provide additional support for the organizational logic of the sulfide oxidation pathway in which glutathione persulfide is the first intermediate formed. PMID:25225291

Libiad, Marouane; Yadav, Pramod Kumar; Vitvitsky, Victor; Martinov, Michael; Banerjee, Ruma

2014-11-01

66

Hydrogen sulfide as a vasculoprotective factor  

PubMed Central

Hydrogen sulfide is a novel mediator with the unique properties of a gasotransmitter and many and varied physiological effects. Included in these effects are a number of cardiovascular effects that are proving beneficial to vascular health. Specifically, H2S can elicit vasorelaxation, prevention of inflammation and leukocyte adhesion, anti-proliferative effects and anti-thrombotic effects. Additionally, H2S is a chemical reductant and nucleophile that is capable of inhibiting the production of reactive oxygen species, scavenging and neutralising reactive oxygen species and boosting the efficacy of endogenous anti-oxidant molecules. These result in resistance to oxidative stress, protection of vascular endothelial function and maintenance of blood flow and organ perfusion. H2S has been shown to be protective in hypertension, atherosclerosis and under conditions of vascular oxidative stress, and deficiency of endogenous H2S production is linked to cardiovascular disease states. Taken together, these effects suggest that H2S has a physiological role as a vasculoprotective factor and that exogenous H2S donors may be useful therapeutic agents. This review article will discuss the vascular effects and anti-oxidant properties of H2S as well as examine the protective role of H2S in some important vascular disease states. PMID:23628084

2013-01-01

67

Removal of hydrogen sulfide from waste treatment plant biogas using the apollo scrubber  

SciTech Connect

The removal of hydrogen sulfide and other sulphur compounds from anaerobic digester gas streams prior to their use as fuel for boilers, stationary engines, and cogeneration units minimizes corrosion problems and reduces sulfur emission loadings. A research program at the Department of Chemical Engineering and Applied Chemistry, University of Toronto in the 1980`s demonstrated the use of a modified flotation cell for the absorption of hydrogen sulfide from a gas stream and its catalytic oxidation to sulfur. The essence of the technology was a proprietary gas liquid contactor which provided very high mass transfer rates at the interface. A bench scale contactor developed at the university achieved hydrogen sulfide removal efficiencies of over 99.9% at atmospheric pressure. A demonstration unit for digester gas scrubbing applications was designed, fabricated, and then installed and evaluated at the Metropolitan Toronto Works Department - Main Treatment Plant (MTP).

Smith, J.W.; Burrowes, P.A.; Gupta, A.; Walton, P.S.; Meffe, S.

1996-12-31

68

Hydrogen Sulfide in Biochemistry and Medicine  

PubMed Central

Abstract Significance: An abundance of experimental evidence suggests that hydrogen sulfide (H2S) plays a prominent role in physiology and pathophysiology. Many targets exist for H2S therapy. The molecular targets of H2S include proteins, enzymes, transcription factors, and membrane ion channels. Recent Advances: Novel H2S precursors are being synthesized and discovered that are capable of releasing H2S in a slow and sustained manner. This presents a novel and advantageous approach to H2S therapy for treatment of chronic conditions associated with a decline in endogenous H2S, such as diabetes and cardiovascular disease. Critical Issues: While H2S is cytoprotective at physiological concentrations, it is not universally cytoprotective, as it appears to have pro-apoptotic actions in cancer cells and is well known to be toxic at supraphysiological concentrations. Many of the pleiotropic effects of H2S on health are associated with the inhibition of inflammation and upregulation of prosurvival pathways. The powerful anti-inflammatory, cytoprotective, immunomodulating, and trophic effects of H2S on the vast majority of normal cells seem to be mediated mainly by its actions as an extremely versatile direct and indirect antioxidant and free radical scavenger. While the overall effects of H2S on transformed (i.e., malignant) cells can be characterized as pro-oxidant and pro-apoptotic, they contrast sharply with the cytoprotective effects on most normal cells. Future Directions: H2S has become a molecule of great interest, and several slow-releasing H2S prodrugs are currently under development. We believe that additional agents regulating H2S bioavailability will be developed during the next 10 years. Antioxid. Redox Signal. 17, 119–140. PMID:22432697

Predmore, Benjamin Lee; Lefer, David Joseph

2012-01-01

69

Hydrogen sulfide in the mammalian cardiovascular system.  

PubMed

For more than a century, hydrogen sulfide (H(2)S) has been regarded as a toxic gas. This review surveys the growing recognition of the role of H(2)S as an endogenous signaling molecule in mammals, with emphasis on its physiological and pathological pathways in the cardiovascular system. In biological fluids, H(2)S gas is a weak acid that exists as about 15% H(2)S, 85% HS(-), and a trace of S(2-). Here, we use "H(2)S" to refer to this mixture. H(2)S has been found to influence heart contractile functions and may serve as a cardioprotectant for treating ischemic heart diseases and heart failure. Alterations of the endogenous H(2)S level have been found in animal models with various pathological conditions such as myocardial ischemia, spontaneous hypertension, and hypoxic pulmonary hypertension. In the vascular system, H(2)S exerts biphasic regulation of a vascular tone with varying effects based on its concentration and in the presence of nitric oxide. Over the past decade, several H(2)S-releasing compounds (NaHS, Na(2)S, GYY4137, etc.) have been utilized to test the effect of exogenous H(2)S under different physiological and pathological situations in vivo and in vitro. H(2)S has been found to promote angiogenesis and to protect against atherosclerosis and hypertension, while excess H(2)S may promote inflammation in septic or hemorrhagic shock. H(2)S-releasing compounds and inhibitors of H(2)S synthesis hold promise in alleviating specific disease conditions. This comprehensive review covers in detail the effects of H(2)S on the cardiovascular system, especially in disease situations, and also the various underlying mechanisms. PMID:22304473

Liu, Yi-Hong; Lu, Ming; Hu, Li-Fang; Wong, Peter T-H; Webb, George D; Bian, Jin-Song

2012-07-01

70

Thermochemical hydrogen production via a cycle using barium and sulfur - Reaction between barium sulfide and water  

NASA Technical Reports Server (NTRS)

The reaction between barium sulfide and water, a reaction found in several sulfur based thermochemical cycles, was investigated kinetically at 653-866 C. Gaseous products were hydrogen and hydrogen sulfide. The rate determining step for hydrogen formation was a surface reaction between barium sulfide and water. An expression was derived for the rate of hydrogen formation.

Ota, K.; Conger, W. L.

1977-01-01

71

New inhibitors of hydrogen sulfide corrosion for gas-turbine oils  

Microsoft Academic Search

Along with the development of deposits of natural gas containing hydrogen sulfide, it has become extremely urgent to provide corrosion protection for the equipment in gas pumping stations and gas processing plants. In the presence of moisture and hydrogen sulfide, the rates of overall and chemical corrosion are several times higher; and hydrogen embrittlement and sulfide cracking of steel may

V. A. Trofimov; V. G. Spirkin; T. O. Ablyazova; A. A. Bocharov

1997-01-01

72

DETERMINATION OF HYDROGEN SULFIDE IN REFINERY FUEL GASES  

EPA Science Inventory

Several widely employed test methods for the iodimetric measurement of hydrogen sulfide in refinery fuel gases are shown to suffer from serious thiol interferences. An absorbing solution consisting of 0.16 M cadmium sulfate/sulfuric acid at pH 3.0 is shown to be effective for the...

73

Kinetics and mechanism of hydrogen sulfide oxidation in sea water  

SciTech Connect

This article provides a comprehensive chemical investigation on the oxidation of acid rain-transported hydrogen sulfides in sea water and on the environmental consequences of their oxidation products. Biochemical and microbiological mechanisms are discussed in detail. Implications and effects for the world's oceans in general are discussed and special emphasis is given to the Black Sea.

Leonov, A.V.; Aizatullin, T.A.

1987-11-01

74

Evaluation of hydrogen sulfide concentrations in Norwegian reservoir fluids  

E-print Network

Knowledge of the hydrogen sulfide content in produced hics. petroleum fluids is important for planning of [HaS] control measures and for material selection. The Norwegian Continental Shelf is known for producing sweet crude oils, and [HaS] has...

Haland, Kjersti

2012-06-07

75

RESEARCH Open Access Effects of hydrogen sulfide on hemodynamics,  

E-print Network

and/or the use of a pre-treatment design, we therefore tested the hypothesis that the H2S donor Introduction: Hydrogen sulfide (H2S) has been shown to improve survival in rodent models of lethal hemorrhage. Conversely, other authors have reported that inhibition of endogenous H2S production improves hemodynamics

Paris-Sud XI, Université de

76

Synthesis of a photocontrollable hydrogen sulfide donor using ketoprofenate photocages.  

PubMed

We report the design, synthesis and application of a directly photocontrollable hydrogen sulfide (H2S) donor, which releases H2S proportionally to the intensity and duration of photoirradiation. Photocontrolled H2S release from this donor was also demonstrated in bovine serum. This H2S donor should be suitable for use in various biological systems. PMID:24280741

Fukushima, Naoki; Ieda, Naoya; Sasakura, Kiyoshi; Nagano, Tetsuo; Hanaoka, Kenjiro; Suzuki, Takayoshi; Miyata, Naoki; Nakagawa, Hidehiko

2014-01-18

77

Solubility and Permeation of Hydrogen Sulfide in Lipid Membranes  

PubMed Central

Hydrogen sulfide (H2S) is mainly known for its toxicity but has recently been shown to be produced endogenously in mammalian tissues and to be associated with physiological regulatory functions. To better understand the role of biomembranes in modulating its biological distribution and effects; we measured the partition coefficient of H2S in models of biological membranes. The partition coefficients were found to be 2.1±0.2, 1.9±0.5 and 2.0±0.6 in n-octanol, hexane and dilauroylphosphatidylcholine liposome membranes relative to water, respectively (25°C). This two-fold higher concentration of H2S in the membrane translates into a rapid membrane permeability, Pm?=?3 cm s?1. We used a mathematical model in three dimensions to gain insight into the diffusion of total sulfide in tissues. This model shows that the sphere of action of sulfide produced by a single cell expands to involve more than 200 neighboring cells, and that the resistance imposed by lipid membranes has a significant effect on the diffusional spread of sulfide at pH 7.4, increasing local concentrations. These results support the role of hydrogen sulfide as a paracrine signaling molecule and reveal advantageous pharmacokinetic properties for its therapeutic applications. PMID:22509322

Cuevasanta, Ernesto; Denicola, Ana; Alvarez, Beatriz; Möller, Matías N.

2012-01-01

78

Biology and therapeutic potential of hydrogen sulfide and hydrogen sulfide-releasing chimeras  

PubMed Central

Hydrogen sulfide, H2S, is a colorless gas with a strong odor that until recently was only considered to be a toxic environmental pollutant with little or no physiological significance. However, the past few years have demonstrated its role in many biological systems and it is becoming increasingly clear that H2S is likely to join nitric oxide (NO) and carbon monoxide (CO) as a major player in mammalian biology. In this review, we have provided an overview of the chemistry and biology of H2S and have summarized the chemistry and biological activity of some natural and synthetic H2S-donating compounds. The naturally occurring compounds discussed include, garlic, sulforaphane, erucin, and iberin. The synthetic H2S donors reviewed include, GYY4137; cysteine analogs; S-propyl cysteine, S-allyl cysteine, S-propargyl cysteine, and N-acetyl cysteine. Dithiolethione and its NSAID and other chimeras such as, L-DOPA, sildenafil, aspirin, diclofenac, naproxen, ibuprofen, indomethacin, and mesalamine have also been reviewed in detail. The newly reported NOSH-aspirin that releases both NO and H2S has also been discussed. PMID:23103569

Kashfi, Khosrow; Olson, Kenneth R.

2012-01-01

79

Biology and therapeutic potential of hydrogen sulfide and hydrogen sulfide-releasing chimeras.  

PubMed

Hydrogen sulfide, H2S, is a colorless gas with a strong odor that until recently was only considered to be a toxic environmental pollutant with little or no physiological significance. However, the past few years have demonstrated its role in many biological systems and it is becoming increasingly clear that H2S is likely to join nitric oxide (NO) and carbon monoxide (CO) as a major player in mammalian biology. In this review, we have provided an overview of the chemistry and biology of H2S and have summarized the chemistry and biological activity of some natural and synthetic H2S-donating compounds. The naturally occurring compounds discussed include, garlic, sulforaphane, erucin, and iberin. The synthetic H2S donors reviewed include, GYY4137; cysteine analogs; S-propyl cysteine, S-allyl cysteine, S-propargyl cysteine, and N-acetyl cysteine. Dithiolethione and its NSAID and other chimeras such as, L-DOPA, sildenafil, aspirin, diclofenac, naproxen, ibuprofen, indomethacin, and mesalamine have also been reviewed in detail. The newly reported NOSH-aspirin that releases both NO and H2S has also been discussed. PMID:23103569

Kashfi, Khosrow; Olson, Kenneth R

2013-03-01

80

Hydrogen sulfide and resolution of acute inflammation: A comparative study utilizing a novel fluorescent probe  

PubMed Central

Hydrogen sulfide is an essential gasotransmitter associated with numerous pathologies. We assert that hydrogen sulfide plays an important role in regulating macrophage function in response to subsequent inflammatory stimuli, promoting clearance of leukocyte infiltrate and reducing TNF-? levels in vivo following zymosan-challenge. We describe two distinct methods of measuring leukocyte hydrogen sulfide synthesis; methylene blue formation following zinc acetate capture and a novel fluorescent sulfidefluor probe. Comparison of these methods, using pharmacological tools, revealed they were complimentary in vitro and in vivo. We demonstrate the application of sulfidefluor probe to spectrofluorimetry, flow cytometry and whole animal imaging, to monitor the regulation of hydrogen sulfide synthesis in vivo during dynamic inflammatory processes. Both methodologies revealed that granulocyte infiltration negatively affects hydrogen sulfide synthesis. Our report offers an insight into the profile of hydrogen sulfide synthesis during inflammation and highlight opportunities raised by the development of novel fluorescent hydrogen sulfide probes. PMID:22787557

Dufton, Neil; Natividad, Jane; Verdu, Elena F.; Wallace, John L.

2012-01-01

81

Activities of various sulfide catalysts in the hydrogenation and hydrolysis of carbon disulfide to hydrogen sulfide  

Microsoft Academic Search

Catalysts for the conversion of gaseous organic sulfur compounds were prepared by impregnating the surface of activated aluminum hydroxide catalyst (AS-64) with various metallic sulfides. It was found that a molybdenum sulfide surface possessed the maximum activity of all the metal systems tested, and that it was far superior to untreated AS-64.

B. S. Medoev; Yu. M. Afanac'ev; S. G. Tibilov

1971-01-01

82

Hydrogenation properties of ruthenium sulfide clusters in acidic zeolites  

SciTech Connect

Catalysts of ruthenium sulfide, dispersed in a series of Y zeolites with various acidic properties, were prepared by ion exchange and subsequent sulfidation. The activities for the reactions of hydrogenation of tetralin and toluene, carried out in the presence of H{sub 2}S (1.9%), vary widely according to the nature of the zeolites. Ruthenium sulfide catalysts are much more active when using acidic zeolite, HY and HYd (dealuminated), and a partially potassium-exchanged KHYd sample, than when using the KY support. The acidic properties of the sulfided RuY catalysts were determined in situ using infrared spectroscopy and the conversion of isooctane. Both methods gave similar rankings of catalyst acidity. The electronic properties of the ruthenium sulfide phase were examined by means of the infrared study of the adsorption of CO. A low-frequency shift of 15 cm{sup -1} was observed for CO adsorbed on RuKY by reference to CO adsorbed on all other samples. The increase in activity for the hydrogenation of aromatics is related to the electron- deficient character of the sulfide particles in the acidic zeolites; as has been proposed, in the literature, for metal catalysts. A superimposed influence of the acidic sites on the adsorption of the aromatic molecule may also occur which could explain the amplitude of the effect (difference of activity between the most and less active catalysts {approximately}200 times) and the variations of activity observed within the series of the acidic catalysts. 33 refs., 10 figs., 7 tabs.

Breysse, M.; Cattenot, M.; Kougionas, V. [Institut de Recherches sur la Catalyse, Villeurbanne (France)] [and others] [Institut de Recherches sur la Catalyse, Villeurbanne (France); and others

1997-06-01

83

Plasma-chemical conversion of hydrogen sulfide into hydrogen and sulfur  

SciTech Connect

A waste-treatment process that recovers both hydrogen and sulfur from hydrogen-sulfide-contaminated industrial wastes is being developed to replace the Claus technology, which recovers only sulfur. The proposed process is based on research reported in the Soviet technical literature and uses microwave (or radio-frequency) energy to initiate plasma-chemical reactions that dissociate hydrogen sulfide into elemental hydrogen and sulfur. In the plasma-chemical process, the gaseous stream would be purified and separated into streams containing the product hydrogen, hydrogen sulfide for recycle to the plasma reactor, and the process purge containing carbon dioxide and water. Since unconverted hydrogen sulfide is recycled to the plasma reactor, the plasma-chemical process has the potential for sulfur recoveries in excess of 99% without the additional tail-gas clean-up processes associated with the Claus technology. Laboratory experiments with pure hydrogen sulfide have confirmed that conversions of over 90% per pass are possible. Experiments with impurities typical of petroleum refinery and natural gas production acid gases have demonstrated that these impurities are compatible with the plasma dissociation process and do not appear to create new waste-treatment problems. Other experiments show that the cyclonic-flow pattern hypothesized by the Russian theoretical analysis of the plasma-chemical process can substantially decrease energy requirements for hydrogen sulfide dissociation while increasing conversion. This process has several advantages over the current Claus-plus-tail-gas-cleanup technology. The primary advantage is the potential for recovering hydrogen more cheaply than the direct production of hydrogen. The difference could amount to an energy savings of 40 {times} 10{sup 15} to 70 {times} 10{sup 15} J/yr in the refining industry, for an annual savings of $500 million to $1,000 million.

Harkness, J.B.L.; Doctor, R.D.; Daniels, E.J.

1993-09-01

84

State-of-the-art hydrogen sulfide control for geothermal energy systems: 1979  

SciTech Connect

Existing state-of-the-art technologies for removal of hydrogen sulfide are discussed along with a comparative assessment of their efficiencies, reliabilities and costs. Other related topics include the characteristics of vapor-dominated and liquid-dominated resources, energy conversion systems, and the sources of hydrogen sulfide emissions. It is indicated that upstream control technologies are preferred over downsteam technologies primarily because upstream removal of hydrogen sulfide inherently controls all downstream emissions including steam-stacking. Two upstream processes for vapor-dominated resources appear promising; the copper sulfate (EIC) process, and the steam converter (Coury) process combined with an off-gas abatement system such as a Stretford unit. For liquid-dominated systems that produce steam, the process where the non-condensible gases are scrubbed with spent geothermal fluid appears to be promising. An efficient downstream technology is the Stretford process for non-condensible gas removal. In this case, partitioning in the surface condenser will determine the overall abatement efficiency. Recommendations for future environmental control technology programs are included.

Stephens, F.B.; Hill, J.H.; Phelps, P.L. Jr.

1980-03-01

85

Japanese experience of hydrogen sulfide: the suicide craze in 2008  

PubMed Central

Most of hydrogen sulfide poisoning has been reported as industrial accidents in Japan. However, since January 2008, a burgeoning of suicide attempts using homemade hydrogen sulfide gas has become evident. By April 2008, the fad escalated into a chain reaction nationwide. Mortality of the poisoning was very high. There were 220 cases of attempted gas suicides during the period of March 27 to June 15, killing 208. An introduction of new method of making the gas, transmitted through message boards on the internet, was blamed for this "outbreak". The new method entailed mixing bath additive and toilet detergent. The National Police Agency instructed internet providers to remove information that could be harmful. Of the victims of the fad in 2008, several cases were serious enough that family members were involved and died. Paramedics and caregivers were also injured secondarily by the gas. This fad has rapidly spread by internet communication, and can happen anywhere in the world. PMID:20920221

2010-01-01

86

Solubility of hydrogen sulfide in aqueous solutions of the single salts sodium sulfate, ammonium sulfate, sodium chloride, and ammonium chloride at temperatures from 313 to 393 K and total pressures up to 10 MPa  

SciTech Connect

New experimental results for the solubility of hydrogen sulfide in aqueous solutions of the single salts sodium sulfate, ammonium sulfate, sodium chloride, and ammonium chloride at temperatures from 313 to 393 K and total pressures up to 10 MPa are reported. As in the salt-free system, a second-hydrogen sulfide-rich--liquid phase is observed at high hydrogen sulfide concentrations. A model to describe the phase equilibrium is presented. Calculations are compared to the new experimental data.

Xia, J.; Kamps, A.P.S.; Rumpf, B.; Maurer, G.

2000-04-01

87

The Global Transcriptional Response of Fission Yeast to Hydrogen Sulfide  

Microsoft Academic Search

BackgroundHydrogen sulfide (H2S) is a newly identified member of the small family of gasotransmitters that are endogenous gaseous signaling molecules that have a fundamental role in human biology and disease. Although it is a relatively recent discovery and the mechanism of H2S activity is not completely understood, it is known to be involved in a number of cellular processes; H2S

Xu Jia; Weizhi He; Alastair I. H. Murchie; Dongrong Chen

2011-01-01

88

Mental retardation in Down syndrome: a hydrogen sulfide hpothesis.  

PubMed

Mental retardation is progressive in Down syndrome: individuals are born with normal intelligence which starts to decline linearly within the first year. This phenomenon can be observed with phenylalanine in patients with phenylketonuria, therefore it is compatible with metabolic intoxication. The toxic compound could be hydrogen sulfide. The amount of the compound is probably increased in Down syndrome by increasing active cystathionine beta synthase. This heuristic hypothesis requires further investigation. PMID:11516234

Kamoun, P

2001-09-01

89

Hydrogen evolution from water through metal sulfide reactions  

SciTech Connect

Transition metal sulfides play an important catalytic role in many chemical reactions. In this work, we have conducted a careful computational study of the structures, electronic states, and reactivity of metal sulfide cluster anions M{sub 2}S{sub X}{sup ?} (M = Mo and W, X = 4–6) using density functional theory. Detailed structural analysis shows that these metal sulfide anions have ground state isomers with two bridging sulfide bonds, notably different in some cases from the corresponding oxides with the same stoichiometry. The chemical reactivity of these metal sulfide anions with water has also been carried out. After a thorough search on the reactive potential energy surface, we propose several competitive, energetically favorable, reaction pathways that lead to the evolution of hydrogen. Selectivity in the initial water addition and subsequent hydrogen migration are found to be the key steps in all the proposed reaction channels. Initial adsorption of water is most favored involving a terminal metal sulfur bond in Mo{sub 2}S{sub 4}{sup ?} isomers whereas the most preferred orientation for water addition involves a bridging metal sulfur bond in the case of W{sub 2}S{sub 4}{sup ?} and M{sub 2}S{sub 5}{sup ?} isomers. In all the lowest energy H{sub 2} elimination steps, the interacting hydrogen atoms involve a metal hydride and a metal hydroxide (or thiol) group. We have also observed a higher energy reaction channel where the interacting hydrogen atoms in the H{sub 2} elimination step involve a thiol (–SH) and a hydroxyl (–OH) group. For all the reaction pathways, the Mo sulfide reactions involve a higher barrier than the corresponding W analogues. We observe for both metals that reactions of M{sub 2}S{sub 4}{sup ?} and M{sub 2}S{sub 5}{sup ?} clusters with water to liberate H{sub 2} are exothermic and involve modest free energy barriers. However, the reaction of water with M{sub 2}S{sub 6}{sup ?} is highly endothermic with a considerable barrier due to saturation of the local bonding environment.

Saha, Arjun; Raghavachari, Krishnan [Department of Chemistry, Indiana University, Bloomington, Indiana 47405 (United States)] [Department of Chemistry, Indiana University, Bloomington, Indiana 47405 (United States)

2013-11-28

90

Synthesis and Evaluation of Phosphorodithioate-Based Hydrogen Sulfide Donors  

PubMed Central

A series of O-aryl- and alkyl-substituted phosphorodithioates were designed and synthesized as hydrogen sulfide (H2S) donors. H2S released capability of these compounds was evaluated by fluorescence methods. O-aryl substituted donors showed slow and sustained H2S release while O-alkylated compounds showed very weak H2S release capability. We also evaluated donors’ protective effects against hydrogen peroxide (H2O2)-induced oxidative damage in myocytes and donors’ toxicity toward B16BL6 mouse melanoma cells. PMID:23917226

Park, Chung-Min; Zhao, Yu; Zhu, Zhaohui; Pacheco, Armando; Peng, Bo; Devarie-Baez, Nelmi O.; Bagdon, Powell; Zhang, Hui

2013-01-01

91

C-H\\ctdot X (X = S, P) hydrogen bonding: The complexes of halothane with dimethyl sulfide and trimethylphosphine  

NASA Astrophysics Data System (ADS)

The formation of C-H⋯S and C-H⋯P hydrogen bonded complexes of halothane, CHBrClCF3, with dimethyl sulfide(-d6) and trimethylphosphine(-d9) have been studied in solutions of liquid krypton using infrared and Raman spectroscopy. In the 1:1 complexes, the halothane CH stretching mode is found to be red-shifted by 43 cm-1 in the dimethyl sulfide complex, and by 63 cm-1 in the trimethylphosphine complex. The complexation enthalpies were derived and amount to -10.7(2) and -11.2(2) kJ mol-1 for the respective complexes. The experiments were supported by ab initio calculations and Monte Carlo simulations. The obtained data for the C-H⋯S and C-H⋯P hydrogen bonds is compared to that of corresponding C-H⋯O and C-H⋯N hydrogen bonds.

Michielsen, B.; Verlackt, C.; van der Veken, B. J.; Herrebout, W. A.

2012-09-01

92

Utilization of Hyperbaric Oxygen Therapy and Induced Hypothermia After Hydrogen Sulfide Exposure  

PubMed Central

Hydrogen sulfide is a toxic gas produced as a byproduct of organic waste and many industrial processes. Hydrogen sulfide exposure symptoms may vary from mild (dizziness, headaches, nausea) to severe lactic acidosis via its inhibition of oxidative phosphorylation, leading to cardiac arrhythmias and death. Treatment is generally supportive. We report the case of a patient presenting with cardiac arrest secondary to hydrogen sulfide exposure treated with both hyperbaric oxygen therapy and therapeutic hypothermia with great improvement in neurologic function. PMID:22004989

Asif, Mir J.; Exline, Matthew C.

2013-01-01

93

Hydrogen Sulfide: Potent Regulator of Vascular Tone and Stimulator of Angiogenesis  

PubMed Central

Hydrogen sulfide is the “third” gasotransmitter on the rise in cardiovascular research. Recent studies show that hydrogen sulfide has a great potential in the regulation of vascular tone of systemic arteries and many molecular targets are discussed. However, the complex mechanism of vascular tone regulation by hydrogen sulfide is only incompletely understood. It seems that a potent interaction of hydrogen sulfide with vascular endothelial growth factor (VEGF) becomes important in angiogenesis, in the process of wound healing, but also in tumor angiogenesis. Hydrogen sulfide exerts anti-inflammatory effects and it could be a pharmacological target in vascular dysfunction in association with obesity-related hypertension as well as in tumor development and progression. However, the underlying molecular pathways still need to be revealed. This review primarily focuses on the regulatory role of hydrogen sulfide in controlling vascular tone. We attempt to provide recent insights into mechanisms by which CSE-dependent hydrogen sulfide plays a role in the regulation of vascular tone by perivascular adipose tissue. The role of KCNQ channels and other ionic permeation pathways as key targets will be discussed. Recent findings which are summarized in this paper provide new insights into molecular mechanisms of hydrogen sulfide that are crucial for understanding vascular dysfunction in cardiovascular disease and possibly angiogenesis. Future research will be extended to investigate the therapeutic potential of hydrogen sulfide and their targets such as KCNQ channels in cardiovascular diseases, angiogenesis and tumor genesis. PMID:23675260

Kohn, Carolin; Dubrovska, Galyna; Huang, Yu; Gollasch, Maik

2012-01-01

94

Modelling studies for hydrogen sulfide fuelled SOFCs  

NASA Astrophysics Data System (ADS)

Solid oxide fuel cells (SOFCs) are high temperature, ceramic electrolyte fuel cells. Unlike most other fuel cells, which require high purity hydrogen to generate electricity, SOFCs can utilize a variety of fuels, including hydrocarbons. This work presents modelling and experimental work performed on a laboratory scale H2S-fuelled SOFC equipped with a novel anode that can electro-oxidize H2S into water vapour and sulphur. Using H2S, a toxic by-product of the fossil fuel industry, such a fuel cell can potentially generate useful electrical energy while disposing off this toxic pollutant on site. In this dissertation, I develop a hierarchy of first principles models for H2S solid oxide fuel cells. The models developed fall into the following four categories: (i) detailed models of H2S electrochemistry; (ii) isothermal 1-D and 2-D transport and reaction models of the 'near cell' region that do not take H2S dissociation into account; (iii) chemical thermodynamics models of H2S dissociation in the fuel channel that also calculate the open circuit voltage (OCV) of the SOFC for the different possible fuels; (iv) fully coupled 2-D transport and reaction models for the complete fuel cell assembly that include heat transfer and H2S dissociation kinetics. The models in the final category above include all the physics and chemistry in a working H2S SOFC by including all transport phenomena, thermodynamically consistent kinetics of the chemical/electrochemical reactions, along with the electrical potential distribution in the fuel cell assembly. These multiphysics models are then used to estimate unknown electrochemical parameters, and to understand and explain experimental data from H2S SOFCs. Experimental results from H2S SOFCs exhibit characteristics which are either poorly explained in current literature or not explained at all e.g., an unusual dependence of cell performance on fuel composition. To support my modelling effort, I and a colleague conducted experiments where the composition and flow rates were varied for both the fuel and oxidant streams to analyze their effect on fuel cell performance. I present these experimental results and demonstrate the importance of thermodynamic and multiphysics modelling in understanding these results.

Monder, Dayadeep

95

Vibrational spectra and tripartite entanglement in hydrogen sulfide  

NASA Astrophysics Data System (ADS)

In this Brief Report an improved u(2) algebraic model is proposed to study both stretching and bending vibrational spectra of a bent triatomic molecule. The model with fewer parameters is used to reproduce the observed spectra of hydrogen sulfide (H2S) with better precision than the u(4) algebraic model. Furthermore, the tripartite entanglement dynamics is investigated for vibrationally localized states in H2S. It is shown that the entanglement of a highly excited state in the bending mode displays better quasiperiodicity than that in the stretch. Those are useful for molecular vibrations and multipartite quantum entanglement.

Hou, Xi-Wen; Huang, Jun; Wan, Ming-Fang

2012-04-01

96

Quantitative evaluation of hydrogen sulfide at 0.3 M and 1.0 M-hydrogen-ion concentration  

E-print Network

? and was determined by titration of 3.0 ml. of the undiluted filtrate with standard sodium hydroxide solution, after boiling for thirty seconds to remove the hydrogen sulfide. The sulfide was quantitatively precipitated by bubbling hydrogen 15 sulfide through... was back titrated with standard potassium permanganate solution. 4. Arsenic (III) - Manganese (II) Separation: The arsenious oxide sample was dissolved with 1.0 g. of sodium hydroxide in 5 ml. of distilled water. This solution was carefully neutralized...

Machel, Albert R.

2013-10-04

97

Seasonal and influent characteristic effects on hydrogen sulfide generation at a water reclamation plant.  

PubMed

Correlations between sulfide generation and seasonal influent wastewater characteristics were identified based on a long-term monitoring program in summer and winter at a water reclamation plant. During summer, the emission rates of hydrogen sulfide (H2S) from the liquid treatment processes increased substantially compared to those during winter due to the increased wastewater temperature. The open tanks/clarifiers were the least significant H2S emission contributors throughout the year. For solids-handling processes, the H2S emission rates did not change during the year due to similar sludge characteristics in the different seasons. The fate of sulfide in liquid treatment processes was investigated as an alternative to estimation of H2S emissions. H2S emission from the wet well and screens was proven to be robustly associated with the wastewater temperature, flow rate, 5-day biochemical oxygen demand and total Kjeldahl nitrogen levels. However, the correlation between influent parameters and H2S emission from aerated grit chambers was not statistically significant. PMID:25353935

Zhang, Yanming; Moschandreas, Demetrios; Pagilla, Krishna

2014-10-01

98

Modeling of Syngas Reactions and Hydrogen Generation Over Sulfides  

SciTech Connect

The objective of the research is to analyze pathways of reactions of hydrogen with oxides of carbon over sulfides, and to predict which characteristics of the sulfide catalyst (nature of metal, defect structure) give rise to the lowest barriers toward oxygenated hydrocarbon product. Reversal of these pathways entails the generation of hydrogen, which is also proposed for study. In this first year of study, adsorption reactions of H atoms and H{sub 2} molecules with MoS{sub 2}, both in molecular and solid form, have been modeled using high-level density functional theory. The geometries and strengths of the adsorption sites are described and the methods used in the study are described. An exposed MO{sup IV} species modeled as a bent MoS{sub 2} molecule is capable of homopolar dissociative chemisorption of H{sub 2} into a dihydride S{sub 2}MoH{sub 2}. Among the periodic edge structures of hexagonal MoS{sub 2}, the (1{bar 2}11) edge is most stable but still capable of dissociating H{sub 2}, while the basal plane (0001) is not. A challenging task of theoretically accounting for weak bonding of MoS{sub 2} sheets across the Van der Waals gap has been addressed, resulting in a weak attraction of 0.028 eV/MoS{sub 2} unit, compared to the experimental value of 0.013 eV/MoS{sub 2} unit.

Kamil Klier; Jeffery A. Spirko; Michael L. Neiman

2002-09-17

99

Catalysts for the selective oxidation of hydrogen sulfide to sulfur  

DOEpatents

This invention provides catalysts for the oxidation of hydrogen sulfide. In particular, the invention provides catalysts for the partial oxidation of hydrogen sulfide to elemental sulfur and water. The catalytically active component of the catalyst comprises a mixture of metal oxides containing titanium oxide and one or more metal oxides which can be selected from the group of metal oxides or mixtures of metal oxides of transition metals or lanthanide metals. Preferred metal oxides for combination with TiO.sub.2 in the catalysts of this invention include oxides of V, Cr, Mn, Fe, Co, Ni, Cu, Nb, Mo, Tc, Ru, Rh, Hf, Ta, W, Au, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Catalysts which comprise a homogeneous mixture of titanium oxide and niobium (Nb) oxide are also provided. A preferred method for preparing the precursor homogenous mixture of metal hydroxides is by coprecipitation of titanium hydroxide with one or more other selected metal hydroxides. Catalysts of this invention have improved activity and/or selectivity for elemental sulfur production. Further improvements of activity and/or selectivity can be obtained by introducing relatively low amounts (up to about 5 mol %)of a promoter metal oxide (preferably of metals other than titanium and that of the selected second metal oxide) into the homogeneous metal/titanium oxide catalysts of this invention.

Srinivas, Girish (Thornton, CO); Bai, Chuansheng (Baton Rouge, LA)

2000-08-08

100

Hydrogen sulfide treatment induces angiogenesis after cerebral ischemia.  

PubMed

Hydrogen sulfide (H2 S) is a potent vasodilator and regulates cardiovascular homeostasis. Furthermore, H2 S has a crucial role in ischemia-reperfusion injuries, especially of the heart, liver, and kidneys. This study indicates that treatment with hydrogen sulfide is able to restore neurological function after ischemic stroke by promoting angiogenesis. Treatment with H2 S augments angiogenesis in the peri-infarct area, and it significantly improves functional outcomes after 2 weeks in a rat MCAO model. H2 S promotes the phosphorylation of AKT and ERK and increases the expression of vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1). H2 S-treated rats showed more newly synthesized endothelial cells in the ischemic lesion (2.31-fold, P?

Jang, Hyunduk; Oh, Mi-Young; Kim, Young-Ju; Choi, In-Young; Yang, Hye Sung; Ryu, Wi-Sun; Lee, Seung-Hoon; Yoon, Byung-Woo

2014-11-01

101

PRODUCTION OF HYDROGEN BY SUPERADIABATIC DECOMPOSITION OF HYDROGEN SULFIDE  

E-print Network

energy, and with no additional carbon dioxide (CO2) emissions. GTI has envisioned a process comprising of feed gas impurities (i.e., CO2, CH4, etc.) in the product gas, and their effect on reactor performance as a feedstock in the range of equivalence ratios from 2 to 5 with hydrogen output at about 20%. The performed

102

Catalytic reduction of CO with hydrogen sulfide. 4. Temperature-programmed desorption of methanethiol on anatase, rutile, and sulfided rutile  

SciTech Connect

The interaction of methanethiol with anatase, rutile, and sulfided rutile was studied by temperature-programmed desorption. Dissociative adsorption occurs on rutile but is insignificant on anatase. Decomposition products are dominated by H/sub 2/ on rutile and by CH/sub 4/ on sulfided rutile. In both cases desorption occurs between 500 and 775 K. The 5- and 4-coordinate sites on the (110) face of rutile are proposed as the active sites for decomposition. The dominance of methane on a sulfided surface is attributed to the relatively large supply of highly mobile surface hydrogen atoms.

Beck, D.D.; White, J.M.; Ratcliffe, C.T.

1986-07-03

103

The reduction of hexavalent uranium by hydrogen sulfide in aqueous solutions at increased temperatures and pressures  

Microsoft Academic Search

In connection with a study of the conditions of transport and deposition of uranium by hydrothermal solutions in the formation of uranium deposits, experiments were conducted earlier on the reduction of hexavalent uranium with hydrogen sulfide at temperatures up to 300~ in sulfate and carbonate solutions [I]. However, the amount of hydrogen sulfide in these experiments was not particularly monitored;

R. P. Rafal'skii; B. S. Osipov

1971-01-01

104

Removal of the hydrogen sulfide contained in a gas of high carbon dioxide content  

Microsoft Academic Search

A process is described for removing hydrogen sulfide from a gas containing hydrogen sulfide mixed with a large amount of carbon dioxide. It comprises the successive steps of contacting the gas with an aqueous solution of ammonium sulfite so as to form ammonium thiosulfate; decomposing the ammonium thiosulfate to sulfur, ammonia, sulfur dioxide, and water; and recovering the sulfur and

P. Renault; A. Deschamps; C. Dezael

1974-01-01

105

A STUDY TO EVALUATE CARBON MONOXIDE AND HYDROGEN SULFIDE CONTINUOUS EMISSION MONITORS AT AN OIL REFINERY  

EPA Science Inventory

An eleven month field evaluation was done on five hydrogen sulfide and four carbon monoxide monitors located at an oil refinery. The hydrogen sulfide monitors sampled a fuel gas feed line and the carbon monoxide monitors sampled the emissions from a fluid cat cracker (FCC). Two o...

106

Studies of molybdenum sulfide catalysts: effects of pretreatment on olefin hydrogenation activity  

Microsoft Academic Search

Various models have been proposed for the active sites in hydrogenation and hydrogenolysis reactions on molybdenum sulfide catalysts. The role played by edge and basal sites of the sulfide in both oxygen chemisorption and in hydrogenation is still moot, although the question has been often investigated. The authors have chosen to study the effect of catalyst preparation and pretreatment on

D. G. Kalthod; S. W. Weller

1986-01-01

107

30 CFR 550.215 - What hydrogen sulfide (H2S) information must accompany the EP?  

...2014-07-01 2014-07-01 false What hydrogen sulfide (H2S) information must accompany...DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL...Exploration Plans (ep) § 550.215 What hydrogen sulfide (H2 S) information must...

2014-07-01

108

30 CFR 250.215 - What hydrogen sulfide (H2S) information must accompany the EP?  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false What hydrogen sulfide (H2S) information must accompany...DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL...Exploration Plans (ep) § 250.215 What hydrogen sulfide (H2S) information must...

2011-07-01

109

30 CFR 250.215 - What hydrogen sulfide (H2S) information must accompany the EP?  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false What hydrogen sulfide (H2S) information must accompany...DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL...Exploration Plans (ep) § 250.215 What hydrogen sulfide (H2S) information must...

2010-07-01

110

30 CFR 550.215 - What hydrogen sulfide (H2S) information must accompany the EP?  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false What hydrogen sulfide (H2S) information must accompany...DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL...Exploration Plans (ep) § 550.215 What hydrogen sulfide (H2 S) information must...

2012-07-01

111

30 CFR 550.215 - What hydrogen sulfide (H2S) information must accompany the EP?  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false What hydrogen sulfide (H2S) information must accompany...DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL...Exploration Plans (ep) § 550.215 What hydrogen sulfide (H2 S) information must...

2013-07-01

112

Airborne sulfur trace species intercomparison campaign: Sulfur dioxide, dimethylsulfide, hydrogen sulfide, carbon disulfide, and carbonyl sulfide  

NASA Technical Reports Server (NTRS)

Results from an airborne intercomparison of techniques to measure tropospheric levels of sulfur trace gases are presented. The intercomparison was part of the NASA Global Tropospheric Experiment (GTE) and was conducted during the summer of 1989. The intercomparisons were conducted on the Wallops Electra aircraft during flights from Wallops Island, Virginia, and Natal, Brazil. Sulfur measurements intercompared included sulfur dioxide (SO2), dimethylsulfide (DMS), hydrogen sulfide (H2S), carbon disulfide (CS2), and carbonyl sulfide (OCS). Measurement techniques ranged from filter collection systems with post-flight analyses to mass spectrometer and gas chromatograph systems employing various methods for measuring and identifying the sulfur gases during flight. Sampling schedules for the techniques ranged from integrated collections over periods as long as 50 minutes to one- to three-minute samples every ten or fifteen minutes. Several of the techniques provided measurements of more than one sulfur gas. Instruments employing different detection principles were involved in each of the sulfur intercomparisons. Also included in the intercomparison measurement scenario were a host of supporting measurements (i.e., ozone, nitrogen oxides, carbon monoxide, total sulfur, aerosols, etc.) for purposes of: (1) interpreting results (i.e., correlation of any noted instrument disagreement with the chemical composition of the measurement environment); and (2) providing supporting chemical data to meet CITE-3 science objectives of studying ozone/sulfur photochemistry, diurnal cycles, etc. The results of the intercomparison study are briefly discussed.

Gregory, Gerald L.; Hoell, James M., Jr.; Davis, Douglas D.

1991-01-01

113

Experimental partitioning of uranium between liquid iron sulfide and liquid silicate: Implications for radioactivity in the Earth's core  

E-print Network

Experimental partitioning of uranium between liquid iron sulfide and liquid silicate: Implications Measurable uranium (U) is found in metal sulfide liquids in equilibrium with molten silicate at conditions Inc. All rights reserved. 1. Introduction The core's heat budget has an important influence on many

Minarik, William

114

Endogenous hydrogen sulfide is involved in the pathogenesis of atherosclerosis  

SciTech Connect

Atherosclerosis is a chronic, complex, and progressive pathological process in large and medium sized arteries. The exact mechanism of this process remains unclear. Hydrogen sulfide (H{sub 2}S), a novel gasotransmitter, was confirmed as playing a major role in the pathogenesis of many cardiovascular diseases. It plays a role in vascular smooth muscle cell (VSMC) proliferation and apoptosis, participates in the progress of hyperhomocysteinemia (HHCY), inhibits atherogenic modification of LDL, interferes with vascular calcification, intervenes with platelet function, and there are interactions between H{sub 2}S and inflammatory processes. The role of H{sub 2}S in atherosclerotic pathogenesis highlights the mysteries of atherosclerosis and inspires the search for innovative therapeutic strategies. Here, we review the studies to date that have considered the role of H{sub 2}S in atherosclerosis.

Qiao, Wang [Department of Pediatrics, Peking University First Hospital, Beijing 100034 (China)] [Department of Pediatrics, Peking University First Hospital, Beijing 100034 (China); Chaoshu, Tang [Department of Physiology and Pathophysiology, Health Sciences Center, Peking University, Beijing 100034 (China) [Department of Physiology and Pathophysiology, Health Sciences Center, Peking University, Beijing 100034 (China); Key Laboratory of Molecular Cardiovascular Medicine, Ministry of Education (China); Hongfang, Jin, E-mail: jinhongfang51@126.com [Department of Pediatrics, Peking University First Hospital, Beijing 100034 (China)] [Department of Pediatrics, Peking University First Hospital, Beijing 100034 (China); Junbao, Du, E-mail: junbaodu1@126.com [Department of Pediatrics, Peking University First Hospital, Beijing 100034 (China)] [Department of Pediatrics, Peking University First Hospital, Beijing 100034 (China)

2010-05-28

115

Hydrogen sulfide and its modulation in arterial hypertension and atherosclerosis.  

PubMed

Apart from nitric oxide (NO) and carbon monoxide (CO), hydrogen sulfide (H?S) is the third gaseous mediator in mammals. H?S is synthesized from L-cysteine by cystathionine ?-synthase (CBS), cystathionine ?-lyase (CSE), or by sequential action of alanine aminotransferase and 3-mercaptopyruvate sulfurtransferase. In the cardiovascular system, H?S is involved in the regulation of vascular tone and blood pressure, inhibits atherogenesis, and protects myocardium from ischemia-reperfusion injury. Recently, the first organic, water-soluble H?S donor, GYY4137, has been synthesized. In addition, H?S-releasing derivatives of several currently used drugs such as sildenafil, diclofenac, aspirin and mesalamine were obtained. Such compounds may be used in the future treatment of cardiovascular diseases. In this article, I describe the role of H?S in the regulation of blood pressure and in the pathogenesis of arterial hypertension and atherosclerosis which are two most common cardiovascular disorders. PMID:20545623

Be?towski, J; Jamroz-Wi?niewska, A; Tokarzewska, D

2010-10-01

116

Robustness of the microaerobic removal of hydrogen sulfide from biogas.  

PubMed

Several disturbances presented in full-scale digesters can potentially affect the efficiency of the microaerobic removal process. This study evaluates the variation of the sulfur load and the performance of the system in situations of oxygen lack or excess and after normal rates are recovered. The process was shown to recover from oxygen lack or excess within 28 h when the original conditions were restored in a pilot-plant digester of 200 L treating sewage sludge with HRT of 20 days. The decrease of the sulfur load to the digester did not affect the biogas composition in the short-term and when oxygen rate was reduced to adjust to the lower hydrogen sulfide production, the removal proceeded normally with a lower unemployed oxygen amount. The digester opening to remove accumulated sulfur in the headspace did not alter process performance once the microaerobic removal was restarted. PMID:22466581

Díaz, I; Fdz-Polanco, M

2012-01-01

117

Lifelines Episode 10: Hydrogen Sulfide- What a Gas  

NSDL National Science Digital Library

This is a free audio podcast from the American Physiological Society. Discussion questions, related research, and other teaching resources are available by clicking "collections" tab in the left hand column. Segment 1: What a Gas. University of Alabama ÃÂ Birmingham researchers Jeannette Doeller and David Kraus talk about the amazing properties of hydrogen sulfide gas. Although itÃÂs lethal in even minute quantities, our bodies produce it and use it to good effect. Episode 10 graphic courtesy of David Kraus. Begins at 1:15. Segment 2: Research Progress on Colon Cancer. John Carethers of the University of California San Diego explains his research findings on colon cancer and the role that the DNA mismatch repair system plays. Begins at 15:24.

APS Communications Office (American Physiological Society Communications Office); David Kraus (UAB Public Health); PhD Jeannette Doeller (UAB Public Health)

2008-06-05

118

Hydrogen Sulfide Is a Signaling Molecule and a Cytoprotectant  

PubMed Central

Abstract Significance: Accumulating evidence shows that hydrogen sulfide may function as a signaling molecule in processes such as neuromodulation in the brain and smooth muscle relaxation in the vascular system. It also has a cytoprotective effect, since it can protect neurons and cardiac muscle from oxidative stress and ischemia-reperfusion injury, respectively. Hydrogen sulfide can also modulate inflammation, insulin release, and angiogenesis. Recent Advances: The regulation of the activity of 3-mercaptopyruvate sulfur transferase (3MST) along with cysteine aminotransferase (CAT), one of the H2S producing pathways, has been demonstrated. The production of H2S by the pathway, which is regulated by Ca2+ and facilitated by thioredoxin and dihydrolipoic acid, is also involved in H2S signaling as well as cytoprotection. Sulfur hydration of proteins by H2S has been proposed to modulate protein functions. H2S-sensitive fluorescent probes, which enable us to measure the localization of H2S in real time, have been developed. Critical Issues: The basal concentrations of H2S have recently been measured and found to be much lower than those initially reported. However, the concentration of H2S reached in stimulated cells, as well as the regulation of H2S producing enzymes is not well understood. It has been proposed that some of the effects of H2S on the regulation of enzymes and receptors might be explained through the properties of sulfane sulfur (S0), another form of active sulfur. Future Directions: The determination of H2S concentrations in activated cells using new methods including H2S-sensitive fluorescent probes, as well as the investigation of the effects of H2S using specific inhibitors, may provide better understanding of the physiological function of this molecule. Clarifying mechanisms of H2S activity may also facilitate the development of new therapeutic compounds. Antioxid. Redox Signal. 17, 45–57. PMID:22229673

Shibuya, Norihiro; Kimura, Yuka

2012-01-01

119

Low-level hydrogen sulfide and central nervous system dysfunction.  

PubMed

Forty-nine adults living in Lovington, Tatum, and Artesia, the sour gas/oil sector of Southeastern New Mexico, were tested for neurobehavioral impairment. Contributing hydrogen sulfide were (1) an anaerobic sewage plant; (2) two oil refineries; (3) natural gas/oil wells and (4) a cheese-manufacturing plant and its waste lagoons. Comparisons were to unexposed Wickenburg, Arizona, adults. Neurobehavioral functions were measured in 26 Lovington adults including 23 people from Tatum and Artesia, New Mexico, and 42 unexposed Arizona people. Participants completed questionnaires including chemical exposures, symptom frequencies and the Profile of Mood States. Measurements included balance, reaction time, color discrimination, blink reflex, visual fields, grip strength, hearing, vibration, problem solving, verbal recall, long-term memory, peg placement, trail making and fingertip number writing errors (FTNWE). Average numbers of abnormalities and test scores were adjusted for age, gender, educational level, height and weight, expressed as percent predicted (% pred) and compared by analysis of variance (ANOVA). Ages and educational attainment of the three groups were not statistically significantly different (ssd). Mean values of Lovington residents were ssd from the unexposed Arizona people for simple and choice reaction times, balance with eyes open and closed, visual field score, hearing and grip strength. Culture Fair, digit symbol substitution, vocabulary, verbal recall, peg placement, trail making A and B, FTNWE, information, picture completion and similarities were also ssd. The Lovington adults who averaged 11.8 abnormalities were ssd from, Tatum-Artesia adults who had 3.6 and from unexposed subjects with 2.0. Multiple source community hydrogen sulfide exposures impaired neurobehavioral functions. PMID:20504829

Kilburn, Kaye H; Thrasher, Jack D; Gray, Michael R

2010-08-01

120

Selective Catalytic Oxidation of Hydrogen Sulfide--Systems Analysis for IGCC Applications  

SciTech Connect

Selective catalytic oxidation of hydrogen sulfide (SCOHS) has been evaluated conceptually for IGCC applications, and the theoretical limits of reaction performance, process performance, and economic potential in IGCC have been estimated. Syngas conditions that have high partial pressures of total sulfur result in substantial liquid sulfur retention within the catalyst bed, with relatively complex processing being required. Applications that have much lower total sulfur partial pressure in the process gas might permit SCOHS operation under conditions where little liquid sulfur is retained in the catalyst, reducing the processing complexity and possibly improving the desulfurization performance. The results from our recent IGCC process evaluations using the SCOHS technology and conventional syngas cleaning are presented, and alternative SCOHS process configurations and applications that provide greater performance and cost potential are identified.

Newby, R.A.; Keairns, D.L.; Alvin, M.A.

2006-09-01

121

Interaction of beggiatoa and rice plant: detoxification of hydrogen sulfide in the rice rhizosphere.  

PubMed

Beggiatoa was obtained from six habitats, including four water-saturated soils from rice fields. The isolate of Beggiatoa from Bernard clay, when reinoculated into soil treatments from pure culture, significantly reduced hydrogen sulfide levels in soils and increased oxygen release from rice plants. Rice plants significantly increased Beggiatoa survival in flooded soils. Some hydrogen sulfide was necessary for survival of the Bernard clay isolate; high concentrations of hydrogen sulfide killed the Bernard clay isolate but were tolerated by a Crowley silt loam isolate from Eagle Lake, Texas. The results suggest that Beggiatoa may be an element of wetlands plant ecosystems. PMID:17844038

Joshi, M M; Hollis, J P

1977-01-14

122

Metal?organic frameworks for the storage and delivery of biologically active hydrogen sulfide  

SciTech Connect

Hydrogen sulfide is an extremely toxic gas that is also of great interest for biological applications when delivered in the correct amount and at the desired rate. Here we show that the highly porous metal-organic frameworks with the CPO-27 structure can bind the hydrogen sulfide relatively strongly, allowing the storage of the gas for at least several months. Delivered gas is biologically active in preliminary vasodilation studies of porcine arteries, and the structure of the hydrogen sulfide molecules inside the framework has been elucidated using a combination of powder X-ray diffraction and pair distribution function analysis.

Allan, Phoebe K.; Wheatley, Paul S.; Aldous, David; Mohideen, M. Infas; Tang, Chiu; Hriljac, Joseph A.; Megson, Ian L.; Chapman, Karena W.; De Weireld, Guy; Vaesen, Sebastian; Morris, Russell E. (St Andrews)

2012-04-02

123

Acid production from sulfide minerals using hydrogen peroxide weathering  

Microsoft Academic Search

Sulfide mineral weathering is a major source of acid generation in mining environments. Oxidation and hydrolysis reactions in soil and geologic material under earth surface conditions causes weathering of reduced sulfide minerals resulting in liberation of weathering products including acid. Pyrite and marcasite are minerals common in mine environments that cause acid generation. Many other sulfide minerals are present in

Stuart R Jennings; Douglas J Dollhopf; William P Inskeep

2000-01-01

124

Effect of swine manure dilution on ammonia, hydrogen sulfide, carbon dioxide, and sulfur dioxide releases.  

PubMed

Animal manure is a significant source of environmental pollution and manure dilution in barn cleaning and slurry storage is a common practice in animal agriculture. The effect of swine manure dilution on releases of four pollutant gases was studied in a 30-day experiment using eight manure reactors divided into two groups. One group was treated with swine manure of 6.71% dry matter and another with manure diluted with water to 3.73% dry matter. Ammonia release from the diluted manure was 3.32 mg min(-1)m(-2) and was 71.0% of the 4.67 mg min(-1)m(-2) from the undiluted manure (P<0.01). Because the ammonia release reduction ratio was lower than the manure dilution ratio, dilution could increase the total ammonia emissions from swine manure, especially in lagoons with large liquid surface areas. Carbon dioxide release of 87.3 mg min(-1)m(-2) from the diluted manure was 56.4% of the 154.8 mg min(-1)m(-2) from the undiluted manure (P<0.01). Manure dry matter was an important factor for carbon dioxide release from manure. No differences were observed between the treatments (P>0.05) for both hydrogen sulfide and sulfur dioxide releases. Therefore, dilution could also significantly increase the total releases of hydrogen sulfide and sulfur dioxide to the environment because dilution adds to the total manure volume and usually also increases the total gas release surface area. PMID:20850169

Ni, Ji-Qin; Heber, Albert J; Sutton, Alan L; Kelly, Dan T; Patterson, John A; Kim, Sun-Tae

2010-11-01

125

Mechanism for the hydrogen sulfide-induced growth limitation in wetland macrophytes  

Microsoft Academic Search

Hydrogen sulfide, a phytotoxin that often accumulates in anoxic marine and freshwater marsh soils, suppressed the activity of alcohol dehydrogenase (ADH), the enzyme that catalyzes the terminal step in alcoholic fermentation, in the roots of two wetland macrophytes. This inhibition of root ADH activity with increasing sulfide concentration was associated with decreases in root total adenine nucleotide pool (ATP +

MARGUERITE S. KOCH; IRVING A. MENDELSSOHN; KAREN L. MCKEE

1990-01-01

126

The Determination of Hydrogen Sulfide in Stack Gases, Iodometric Titration After Sulfite Removal.  

ERIC Educational Resources Information Center

The determination of hydrogen sulfide in effluents from coal-fired furnaces and incinerators is complicated by the presence of sulfur oxides (which form acids). Organic compounds also may interfere with or prevent the formation of the cadmium sulfide precipitate or give false positive results because of reaction with iodine. The report presents a…

Robles, E. G.

127

76 FR 69136 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting  

Federal Register 2010, 2011, 2012, 2013

...CFR Part 372 [EPA-HQ-TRI-2009-0844; FRL-9488-5] RIN 2025-AA27 Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting AGENCY: Environmental Protection Agency (EPA). ACTION: Lifting of Administrative Stay for...

2011-11-08

128

VERIFICATION OF AMBIENT MONITORING TECHNOLOGIES FOR AMMONIA AND HYDROGEN SULFIDE AT ANIMAL FEEDING OPERATIONS  

EPA Science Inventory

The increasing concentration of livestock agriculture into animal feeding operations (AFOs) has raised concerns about the environmental and potential health impact of the emissions from AFOs into the atmosphere. Gaseous ammonia (NH3) and hydrogen sulfide (H2...

129

EMERSION IN THE MANGROVE FOREST FISH 'RIVULUS MARMORATUS': A UNIQUE RESPONSE TO HYDROGEN SULFIDE  

EPA Science Inventory

The mangrove forest fish Rivulus marmoratus (Cyprinodontidae) has frequently been observed out of water, a phenomenon generally attributed to habitat drying. The authors tested the hypothesis that hydrogen sulfide, a substance characteristically found in their environment, can se...

130

Experimental heat capacities of nitrogen-hydrogen sulfide mixtures at elevated pressures  

Microsoft Academic Search

The ratio of the heat capcity at a pressure to the heat capacity at a low pressure was measured experimentally for 2 mixtures of gases, one containing 91.4 mol % nitrogen and 8.6 mol % hydrogen sulfide and the other containing 76.5 mol % nitrogen, 22.2 mol % hydrogen sulfide, and 1.3 mol % carbon dioxide. Data were obtained at

Gerald P. Hamaliuk; P. Raj Bishnoi; Donald B. Robinson

1974-01-01

131

The solubility of elemental sulfur in methane, carbon dioxide and hydrogen sulfide gas  

E-print Network

THE SOLUBILITY OF ELEMENTAL SULFUR IN METHANE, CARBON DIOXIDE AND HYDROGEN SULFIDE GAS By Denton R. Wieland A Dissertation Submitted to the Graduate School of The Agricultural and Mechanical College of Texas in partial fulfillment... of the requirements for the degree of DOCTOR OF PHILOSOPHY January 1958 Major Subject: Petroleum Engineering THE SOLUBILITY OF ELEMENTAL SULFUR IN METHANE, CARBON DIOXIDE AND HYDROGEN SULFIDE GAS A Dissertation By DENTON R. WlELAND Library A * "COLLEGE...

Wieland, Denton R.

2013-10-04

132

Removal of hydrogen sulfide from simulated geothermal brines by reaction with oxygen. Final report, October 6, 1975February 4, 1977  

Microsoft Academic Search

A process for controlling hydrogen sulfide emissions and corrosivity in geothermal systems has been evaluated on a small laboratory pilot plant scale and shown to be technically feasible. The hydrogen sulfide was oxidized by oxygen injected directly into an 11.4-liter-(3-gallon)-per-minute flowing stream of simulated geothermal brine. The oxidation of the sulfide was complete at oxygen:sulfide mole ratios of 1.25:1 to

J. S. Wilson; J. E. King; G. R. Bullard

1977-01-01

133

Inhaled Hydrogen Sulfide Prevents Endotoxin-Induced Systemic Inflammation and Improves Survival by Altering Sulfide Metabolism in Mice  

PubMed Central

Abstract Aims: The role of hydrogen sulfide (H2S) in endotoxin (lipopolysaccharide [LPS])-induced inflammation is incompletely understood. We examined the impact of H2S breathing on LPS-induced changes in sulfide metabolism, systemic inflammation, and survival in mice. Results: Mice that breathed air alone exhibited decreased plasma sulfide levels and poor survival rate at 72?h after LPS challenge. Endotoxemia markedly increased alanine aminotransferase (ALT) activity and nitrite/nitrate (NOx) levels in plasma and lung myeloperoxidase (MPO) activity in mice that breathed air. In contrast, breathing air supplemented with 80?ppm of H2S for 6?h after LPS challenge markedly improved survival rate compared to mice that breathed air alone (p<0.05). H2S breathing attenuated LPS-induced increase of plasma ALT activity and NOx levels and lung MPO activity. Inhaled H2S suppressed LPS-induced upregulation of inflammatory cytokines, while it markedly induced anti-inflammatory interleukin (IL)-10 in the liver. Beneficial effects of H2S inhalation after LPS challenge were associated with restored sulfide levels and markedly increased thiosulfate levels in plasma. Increased thiosulfate levels after LPS challenge were associated with upregulation of rhodanese, but not cystathionine-?-lyase (CSE), in the liver. Administration of sodium thiosulfate dose-dependently improved survival after LPS challenge in mice. Innovation: By measuring changes in plasma levels of sulfide and sulfide metabolites using an advanced analytical method, this study revealed a critical role of thiosulfate in the protective effects of H2S breathing during endotoxemia. Conclusion: These observations suggest that H2S breathing prevents inflammation and improves survival after LPS challenge by altering sulfide metabolism in mice. Antioxid. Redox Signal. 17, 11—21. PMID:22221071

Tokuda, Kentaro; Kida, Kotaro; Marutani, Eizo; Crimi, Ettore; Bougaki, Masahiko; Khatri, Ashok; Kimura, Hideo

2012-01-01

134

Physiological and pharmacological features of the novel gasotransmitter: Hydrogen sulfide  

PubMed Central

Hydrogen sulfide (H2S) has been known for hundreds of years because of its poisoning effect. Once the basal bio-production became evident its pathophysiological role started to be investigated in depth. H2S is a gas that can be formed by the action of two enzymes, cystathionine gamma-lyase and cystathionine beta-synthase, both involved in the metabolism of cysteine. It has several features in common with the other two well known “gasotransmitters” (nitric oxide and carbon monoxide) in the biological systems. These three gasses share some biological targets; however, they also have dissimilarities. For instance, the three gases target heme-proteins and open KATP channels; H2S as NO is an antioxidant, but in contrast to the latter molecule, H2S does not directly form radicals. In the last years H2S has been implicated in several physiological and pathophysiological processes such as long term synaptic potentiation, vasorelaxation, pro- and anti-inflammatory conditions, cardiac inotropism regulation, cardioprotection, and several other physiological mechanisms. We will focus on the biological role of H2S as a molecule able to trigger cell signaling. Our attention will be particularly devoted on the effects in cardiovascular system and in cardioprotection. We will also provide available information on H2S-donating drugs which have so far been tested in order to conjugate the beneficial effect of H2S with other pharmaceutical properties. PMID:19285949

Mancardi, Daniele; Penna, Claudia; Merlino, Annalisa; Del Soldato, Piero; Wink, David A.; Pagliaro, Pasquale

2012-01-01

135

Hydrogen sulfide as a potent cardiovascular protective agent.  

PubMed

Hydrogen sulfide (H2S) is a well-known toxic gas with the characteristic smell of rotten eggs. It is synthesized endogenously in mammals from the sulfur-containing amino acid l-cysteine by the action of several distinct enzymes: cystathionine-?-lyase (CSE), cystathionine-ß-synthase (CBS), and 3-mercaptopyruvate sulfurtransferase (3-MST) along with cysteine aminotransferase (CAT). In particular, CSE is considered to be the major H2S-producing enzyme in the cardiovascular system. As the third gasotransmitter next to nitric oxide (NO) and carbon monoxide (CO), H2S plays an important role in the regulation of vasodilation, angiogenesis, inflammation, oxidative stress and apoptosis. Growing evidence has demonstrated that this gas exerts a significant protective effect against the progression of cardiovascular diseases by a number of mechanisms such as vasorelaxation, inhibition of cardiovascular remodeling and resistance to form foam cells. The aim of this review is to provide an overview of the physiological functions of H2S and its protection against several major cardiovascular diseases, and to explore its potential health and therapeutic benefits. A better understanding will help develop novel H2S-based therapeutic interventions for these diseases. PMID:25058799

Yu, Xiao-Hua; Cui, Li-Bao; Wu, Kai; Zheng, Xi-Long; Cayabyab, Francisco S; Chen, Zhi-Wei; Tang, Chao-Ke

2014-11-01

136

Kinetics and mechanisms of hydrogen sulfide adsorption by biochars.  

PubMed

Three different biochars as cost-effective substitutes for activated carbon (AC) were tested for their hydrogen sulfide (H2S) adsorption ability. The biochars were produced from camphor (SC), bamboo (SB), and rice hull (SR) at 400°C by oxygen-limited pyrolysis. The surface area (SA), pH, and Fourier transform infrared spectras of the biochars and AC were compared. The maximum removal rates and the saturation constants were obtained using the Michaelis-Menten-type equation. The three biochars were found to be alkaline, and the SAs of the biochars were much smaller than that of the AC. The H2S breakthrough capacity was related to the local pH within the pore system of the biochar. The order observed in terms of both biochar and AC adsorption capacity was SR>SB>SC>AC. SR efficiently removed H2S within the inlet concentration range of 10-50 ?L/L. Biochars derived from agricultural/forestry wastes are a promising H2S adsorbent with distinctive properties. PMID:23455220

Shang, Guofeng; Shen, Guoqing; Liu, Liang; Chen, Qin; Xu, Zhiwei

2013-04-01

137

Carbamoylation abrogates the antioxidant potential of hydrogen sulfide.  

PubMed

Hydrogen sulfide (H2S) has been identified as the third gasotransmitter. Beside its role as signaling molecule in the cardiovascular and nervous system the antioxidant and cyto-protective properties of H2S have gained much attention. In the present study we show that cyanate, an uremic toxin which is found in abundant concentration in sera of patients suffering from chronic kidney disease (CKD), can abrogate the antioxidant and cytoprotective activity of H2S via S-carbamoylation reaction, a reaction that previously has only been shown to have a physiological effect on cysteine groups, but not on H2S. Carbamoylation strongly inhibited the free radical scavenging (ABTS(+·) and alkylperoxyl ROO(·)) properties of H2S. The extent of intracellular ROS formation induced by ROO(·) was diminished by H2S whereas carbamoylation counteracted the protective effect. Reagent HOCl was rapidly inactivated by H2S in contrast to the carbamoylated compound. Protein modification by HOCl was inhibited by H2S but carbamoylation significantly reduced the effect. Thus, S-carbamoylation of low molecular weight thiols by abrogating their antioxidant potential may contribute to the higher oxidative stress observed in CKD. PMID:23896375

Praschberger, Monika; Hermann, Marcela; Laggner, Christian; Jirovetz, Leopold; Exner, Markus; Kapiotis, Stylianos; Gmeiner, Bernhard M K; Laggner, Hilde

2013-11-01

138

[Severe hydrogen sulfide intoxication: a pediatric case of survival].  

PubMed

We report a paediatric case of survival following severe hydrogen sulfide (H2S) gas intoxication. A 13-year-old boy was found submerged to the neck in a manure tank. He was hypothermic, unresponsive with bilateral mydriasis, and had poor oxygen saturation. After intubation, he was transferred to the paediatric intensive care unit of a tertiary care children's hospital. He developed acute respiratory distress syndrome (ARDS) requiring high frequency percussive ventilation. Cardiac evaluation was significant for myocardial infarction and left ventricular function impairment. He completely recovered from the respiratory and cardiac failure. Neurological examinations showed abnormal signals on MRI in the semi-oval center and in the frontal cortex. Follow-up detected partial impairment of axonal fibers of the right external popliteal sciatic nerve. Paediatric cases of survival after H2S intoxication have been rarely reported. Such exposures can evolve to severe ARDS and benefit from high frequency percussive ventilation. Hypothermia and other metabolic abnormalities are now better explained thanks to actual knowledge about endogenous H2S function. Lessons learned from paediatric accidents should result in better information about this threat for farmers and families living in houses with septic tanks, reducing the risk to their own and their children's safety. PMID:22305402

Claudet, I; Marcoux, M-O; Karsenty, C; Rittié, J-L; Honorat, R; Lelong-Tissier, M-C

2012-03-01

139

Increasing prevalence of hydrogen sulfide negative Salmonella in retail meats.  

PubMed

Hydrogen sulfide (H2S) production is considered a typical characteristic of Salmonella and an important marker for Salmonella isolation. In this study, a total of 82 (26%) Salmonella strains were isolated from 113 chicken and 204 pork samples, within which 49 Salmonella strains were H2S positive and 33 were H2S negative. Salmonella enterica serovar Derby was most prevalent in both pork and chicken followed by S. Typhimurium in pork and S. Heidelberg in chicken. Salmonella isolated from pork exhibited a much higher H2S positive rate than those from chicken (68% versus 31%). The most prevalent H2S negative serotypes were S. Derby (40%) and S. Heidelberg (30%) in chicken, and S. Typhimurium (23%) and S. Enteritidis (23%) in pork. spvC, a plasmid-encoded virulence marker, was detected in 51% and 42% of the H2S positive and negative Salmonella respectively. The presence of the two most important serotypes, S. Enteritidis and S. Typhimurium, as well as a virulence plasmid in H2S negative Salmonella suggested that H2S negative Salmonella is also a significant public health concern. Such finding warrants the development of an improved method for effective coverage of H2S negative Salmonella. PMID:24929875

Lin, Dachuan; Yan, Meiying; Lin, Song; Chen, Sheng

2014-10-01

140

Study on Fiber-optic Hydrogen Sulfide Gas Sensor  

NASA Astrophysics Data System (ADS)

We describe a novel fiber-optic gas sensor which hydrogen Sulfide (H2S) gas can be detected by a silver coated fiber bragg grating (FBG). The H2S sensitive material Ag can be coated on the cladding surrounding surface of FBG by conventional silver mirror reaction. The scanning electron microscope (SEM) was applied to analysis the Ag film structure before and after the interaction with H2S gas. By conducting the experiment of Ag-coated optical sensor (AOS), the relation between the H2S gas concentration and absorption spectrum was built. Result shows that while the concentration alters from 0 to 9.32%, a linear response of AOS signal to H2S concentration was observed with the response sensitivity of 0.332 dBm/% and linearity R2=0.9966. Such H2S sensor is suitable for monitoring the H2S hazard as a one time disposable logging-while-drilling sensor.

Zhou, Hong; Wen, Jun-Qing; Zhang, Xiao-Zhen; Wang, Wei; Feng, De-Quan; Wang, Qi; Jia, Fei

141

Satellite measures hydrogen sulfide in a volcanic plume  

NASA Astrophysics Data System (ADS)

For the first time, satellite measurements have been made of hydrogen sulfide (H2S) in a volcanic plume. Volcanoes release H2S in large quantities—yearly global estimates range from 1 to 37 teragrams. Along with sulfur dioxide (SO2), which is estimated to be emitted from volcanoes at about 15-21 teragrams per year, H2S is a major portion of the volcanic sulfur released into the atmosphere. The ratio of H2S to SO2 emissions is useful for studying source conditions, sulfur chemistry, and magma-water interactions. However, unlike SO2, H2S has been challenging to measure in the atmosphere. Clarisse et al. used infrared satellite observations to characterize H2S from the 7-8 August 2008 eruption of the Kasatochi volcano in the Aleutian Islands. The eruption consisted of five explosive events; the observations indicated that the H2S plume was likely associated with the earlier events. The study shows that volcanoes are significant sources of H2S in the atmosphere and demonstrates for the first time that satellites can observe H2S plumes. (Geophysical Research Letters, doi:10.1029/2011GL047402, 2011)

Balcerak, Ernie

2011-07-01

142

Role of Hydrogen Sulfide in the Pathology of Inflammation  

PubMed Central

Hydrogen sulfide (H2S) is a well-known toxic gas that is synthesized in the human body from the amino acids cystathionine, homocysteine, and cysteine by the action of at least two distinct enzymes: cystathionine-?-lyase and cystathionine-?-synthase. In the past few years, H2S has emerged as a novel and increasingly important biological mediator. Imbalances in H2S have also been shown to be associated with various disease conditions. However, defining the precise pathophysiology of H2S is proving to be a complex challenge. Recent research in our laboratory has shown H2S as a novel mediator of inflammation and work in several groups worldwide is currently focused on determining the role of H2S in inflammation. H2S has been implicated in different inflammatory conditions, such as acute pancreatitis, sepsis, joint inflammation, and chronic obstructive pulmonary disease (COPD). Active research on the role of H2S in inflammation will unravel the pathophysiology of its actions in inflammatory conditions and may help develop novel therapeutic approaches for several, as yet incurable, disease conditions. PMID:24278674

Bhatia, Madhav

2012-01-01

143

Selective Catalytic Oxidation of Hydrogen Sulfide--IGCC Applications  

SciTech Connect

Selective catalytic oxidation of hydrogen sulfide (SCOHS) to elemental sulfur using activated carbon and NETL-processed metal oxide catalyst systems has been investigated under bench-scale, simulated pressurized IGCC conditions for use in dry and humid gas cleaning process applications. For this technology to be successful, a 20% cost effective advantage and 1 percentage-point plant efficiency gain over current commercial technology, and <10-15 ppm total gas phase sulfur release into the effluent gas stream must be demonstrated. The results of our bench-scale catalyst/sorbent desulfurization and regeneration efforts for both bulk and polishing sulfur removal indicate that direct selective catalytic oxidation of H2S to elemental sulfur utilizing current activated carbon systems occurs only under conditions of low syngas temperature (<150°C), and in syngas effluent streams containing a low water and CO content. Thus the SCOHS desulfurization process is considered to be only potentially feasible for use in dry gas cleaning conditions for IGCC applications where syngas-CO is shifted to CO2, and regeneration of the catalyst occurs through heating in warm CO2, with simultaneous CO2 sequestration. SCOHS is not considered as a candidate desulfurization approach for use in humid IGCC gas cleaning applications.

Alvin, M.A.; Stevens, R.W.; Newby, R.A.; Keairns, D.L.

2006-09-01

144

Discoveries of hydrogen sulfide as a novel cardiovascular therapeutic.  

PubMed

Hydrogen sulfide (H2S) is an endogenously produced gaseous signaling molecule that elicits a number of cytoprotective effects in mammalian species. H2S was originally considered toxic at elevated levels, but 15 years ago the labile molecule was discovered in mammalian tissue and termed a gasotransmitter, thus opening the door for research aimed towards understanding its physiologic nature. Since then, novel findings have depicted the beneficial aspects of H2S therapy, such as vasodilation, antioxidant upregulation, inflammation inhibition, and activation of anti-apoptotic pathways. These cytoprotective alterations effectively treat multiple forms of cardiac injury at the preclinical level of research. The field has progressed towards instituting novel H2S donors that prove more effective at activating the subsequent cardioprotective enhancements over longer time periods. As more findings explore the efficacy of H2S, research focused on detection of sulfhydrated targets is on the rise. Understanding the molecular mechanisms that stem from H2S treatment may lead the field towards powerful therapeutics in the clinical setting. This review will discuss the cytoprotective and cardioprotective effects of H2S therapy, provide analysis on the molecular alterations that lead to these enhancements, and explore recently developed therapeutics that may bring this gasotransmitter into the clinic in the near future. PMID:25131384

Barr, Larry A; Calvert, John W

2014-01-01

145

Interactions between oxygen homeostasis, food availability, and hydrogen sulfide signaling  

PubMed Central

The ability to sense and respond to stressful conditions is essential to maintain organismal homeostasis. It has long been recognized that stress response factors that improve survival in changing conditions can also influence longevity. In this review, we discuss different strategies used by animals in response to decreased O2 (hypoxia) to maintain O2 homeostasis, and consider interactions between hypoxia responses, nutritional status, and H2S signaling. O2 is an essential environmental nutrient for almost all metazoans as it plays a fundamental role in development and cellular metabolism. However, the physiological response(s) to hypoxia depend greatly on the amount of O2 available. Animals must sense declining O2 availability to coordinate fundamental metabolic and signaling pathways. It is not surprising that factors involved in the response to hypoxia are also involved in responding to other key environmental signals, particularly food availability. Recent studies in mammals have also shown that the small gaseous signaling molecule hydrogen sulfide (H2S) protects against cellular damage and death in hypoxia. These results suggest that H2S signaling also integrates with hypoxia response(s). Many of the signaling pathways that mediate the effects of hypoxia, food deprivation, and H2S signaling have also been implicated in the control of lifespan. Understanding how these pathways are coordinated therefore has the potential to reveal new cellular and organismal homeostatic mechanisms that contribute to longevity assurance in animals. PMID:23233860

Iranon, Nicole N.; Miller, Dana L.

2012-01-01

146

Hydrogen sulfide anion regulates redox signaling via electrophile sulfhydration  

PubMed Central

An emerging aspect of redox signaling is the pathway mediated by electrophilic byproducts, such as nitrated cyclic nucleotide (for example, 8-nitroguanosine 3?,5?-cyclic monophosphate (8-nitro-cGMP)) and nitro or keto derivatives of unsaturated fatty acids, generated via reactions of inflammation-related enzymes, reactive oxygen species, nitric oxide and secondary products. Here we report that enzymatically generated hydrogen sulfide anion (HS?) regulates the metabolism and signaling actions of various electrophiles. HS? reacts with electrophiles, best represented by 8-nitro-cGMP, via direct sulfhydration and modulates cellular redox signaling. The relevance of this reaction is reinforced by the significant 8-nitro-cGMP formation in mouse cardiac tissue after myocardial infarction that is modulated by alterations in HS? biosynthesis. Cardiac HS?, in turn, suppresses electrophile-mediated H-Ras activation and cardiac cell senescence, contributing to the beneficial effects of HS? on myocardial infarction–associated heart failure. Thus, this study reveals HS?-induced electrophile sulfhydration as a unique mechanism for regulating electrophile-mediated redox signaling. PMID:22772154

Nishida, Motohiro; Sawa, Tomohiro; Kitajima, Naoyuki; Ono, Katsuhiko; Inoue, Hirofumi; Ihara, Hideshi; Motohashi, Hozumi; Yamamoto, Masayuki; Suematsu, Makoto; Kurose, Hitoshi; van der Vliet, Albert; Freeman, Bruce A; Shibata, Takahiro; Uchida, Koji; Kumagai, Yoshito; Akaike, Takaaki

2014-01-01

147

Novel Composite Hydrogen-Permeable Membranes for Nonthermal Plasma Reactors for the Decomposition of Hydrogen Sulfide  

SciTech Connect

The goal of this experimental project was to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H{sub 2}S) in a nonthermal plasma and to recover hydrogen (H{sub 2}) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys), but it was not achieved at the moderate pressure conditions used in this study. However, H{sub 2}S was successfully decomposed at energy efficiencies higher than any other reports for the high H{sub 2}S concentration and moderate pressures (corresponding to high reactor throughputs) used in this study.

Morris Argyle; John Ackerman; Suresh Muknahallipatna; Jerry Hamann; Stanislaw Legowski; Gui-Bing Zhao; Sanil John; Ji-Jun Zhang; Linna Wang

2007-09-30

148

Properties of thirteen kinds of adsorbents for removal of hydrogen sulfide, methanethiol, methyl sulfide, trimethylamine, and ammonia.  

PubMed

Adsorption of hydrogen sulfide, methanethiol, methyl sulfide, trimethylamine, and ammonia on thirteen kinds of adsorbents (5 kinds of silicate, 4 kinds of activated carbon, and 4 kinds of zeolite) was measured by gravimetry, at 30 degrees C and 50 Torr, using an adsorption apparatus with a spring balance in order to find the most suitable adsorbent for the removal of these gases by dry process. The relations between the amount of these gases adsorbed (mmol/cm2) on the adsorbent and the surface properties or the porous structure were examined to clarify the mechanism of adsorption of these gases on them through surface pH, pore size distribution, and area of an adsorbed particle of these gases. Among the thirteen adsorbents, the activated carbon Nos. 6 and 7 were the most suitable adsorbent for methanethiol, methyl sulfide, and trimethylamine whose area of an adsobed particle (wrho) was larger than about 17 A2, and zeolite Nos. 12 and 13 were most suitable for removal of hydrogen sulfide and ammonia (wrho less than about 17A2). The amount of these gases adsorbed (mmol/cm2) on these adsorbents was mainly determined by their porous structure rather than by their surface properties. PMID:199769

Miyoshi, T; Tanada, S; Boki, K

1977-01-01

149

Studies of molybdenum sulfide catalysts: effects of pretreatment on olefin hydrogenation activity  

SciTech Connect

Various models have been proposed for the active sites in hydrogenation and hydrogenolysis reactions on molybdenum sulfide catalysts. The role played by edge and basal sites of the sulfide in both oxygen chemisorption and in hydrogenation is still moot, although the question has been often investigated. The authors have chosen to study the effect of catalyst preparation and pretreatment on the properties of unsupported molybdenum disulfide, to avoid some of the problems involved in characterizing supported catalysts. The unsupported sulfide was prepared in situ by the thermal decomposition of ammonium tetrathiomolybdate (ATTM) in flowing helium. In the present paper, unsupported molybdenum sulfide catalysts have been tested for catalytic activity in propene hydrogenation after various pretreatments. This was selected as a test reaction because it gives good conversions at temperatures below the TPR peaks; these mild conditions do not destroy the effects of catalyst pretreatment. Activity was measured with a pulse method, with determination of kinetic constants by a procedure recently described. 44 references.

Kalthod, D.G.; Weller, S.W.

1986-04-01

150

Mobile measurement of methane and hydrogen sulfide at natural gas production site fence lines in the Texas Barnett Shale.  

PubMed

Production of natural gas from shale formations is bringing drilling and production operations to regions of the United States that have seen little or no similar activity in the past, which has generated considerable interest in potential environmental impacts. This study focused on the Barnett Shale Fort Worth Basin in Texas, which saw the number of gas-producing wells grow from 726 in 2001 to 15,870 in 2011. This study aimed to measure fence line concentrations of methane and hydrogen sulfide at natural gas production sites (wells, liquid storage tanks, and associated equipment) in the four core counties of the Barnett Shale (Denton, Johnson, Tarrant, and Wise). A mobile measurement survey was conducted in the vicinity of 4788 wells near 401 lease sites, representing 35% of gas production volume, 31% of wells, and 38% of condensate production volume in the four-county core area. Methane and hydrogen sulfide concentrations were measured using a Picarro G2204 cavity ring-down spectrometer (CRDS). Since the research team did not have access to lease site interiors, measurements were made by driving on roads on the exterior of the lease sites. Over 150 hr of data were collected from March to July 2012. During two sets of drive-by measurements, it was found that 66 sites (16.5%) had methane concentrations > 3 parts per million (ppm) just beyond the fence line. Thirty-two lease sites (8.0%) had hydrogen sulfide concentrations > 4.7 parts per billion (ppb) (odor recognition threshold) just beyond the fence line. Measured concentrations generally did not correlate well with site characteristics (natural gas production volume, number of wells, or condensate production). t tests showed that for two counties, methane concentrations for dry sites were higher than those for wet sites. Follow-up study is recommended to provide more information at sites identified with high levels of methane and hydrogen sulfide. Implications: Information regarding air emissions from shale gas production is important given the recent increase in number of wells in various regions in the United States. Methane, the primary natural gas constituent, is a greenhouse gas; hydrogen sulfide, which can be present in gas condensate, is an odor-causing compound. This study surveyed wells representing one-third of the natural gas production volume in the Texas Barnett Shale and identified the percent of sites that warrant further study due to their fence line methane and hydrogen sulfide concentrations. PMID:25185395

Eapi, Gautam R; Sabnis, Madhu S; Sattler, Melanie L

2014-08-01

151

Slush hydrogen liquid level system  

NASA Technical Reports Server (NTRS)

A discrete capacitance liquid level system developed is specifically for slush hydrogen, but applicable to LOX, LN2, LH2, and RP1 without modification is described. The signal processing portion of the system is compatible with conventional liquid level sensors. Compatibility with slush hydrogen was achieved by designing the sensor with adequate spacing, while retaining the electrical characteristics of conventional sensors. Tests indicate excellent stability of the system over a temperature range of -20 C to 70 C for the circuit and to cryogenic temperatures of the sensor. The sensor was tested up to 40 g's rms random vibration with no damage to the sensor. Operation with 305 m of cable between the sensor and signal processor was demonstrated. It is concluded that this design is more than adequate for most flight and ground applications.

Hamlet, J. F.; Adams, R. G.

1972-01-01

152

Hydrogen sulfide and cerebral microvascular tone in newborn pigs  

PubMed Central

Hydrogen sulfide (H2S) is a gaseous signaling molecule that appears to be involved in numerous biological processes, including regulation of blood pressure and vascular tone. The present study is designed to address the hypothesis that H2S is a functionally significant, endogenous dilator in the newborn cerebrovascular circulation. In vivo experiments were conducted using newborn pigs with surgically implanted, closed, cranial windows. Topical application of H2S concentration-dependently (10?6 to 2 × 10?4 M) dilated pial arterioles. This dilation was blocked by glibenclamide (10?6 M). l-Cysteine, the substrate of the H2S-producing enzymes cystathionine ?-lyase (CSE) and cystathionine ?-synthase (CBS), also dilated pial arterioles. The dilation to l-cysteine was blocked by the CSE inhibitor d,l-propargylglycine (PPG, 10 mM) but was unaffected by the CBS inhibitor amino-oxyacetate (AOA, 1 mM). Western blots detected CSE, but not CBS, in cerebral microvessels, whereas CBS is detected in brain parenchyma. Immunohistological CSE expression is predominantly vascular while CBS is expressed mainly in neurons and astrocytes. l-Cysteine (5 mM) increased H2S concentration in cerebrospinal fluid (CSF), measured by GC-MS, from 561 ± 205 to 2,783 ± 818 nM before but not during treatment with PPG (1,030 ± 70 to 622 ± 78 nM). Dilation to hypercapnia was inhibited by PPG but not AOA. Hypercapnia increased CSF H2S concentration from 763 ± 243 to 4,337 ± 1789 nM before but not during PPG treatment (357 ± 178 vs. 425 ± 217 nM). These data show that H2S is a dilator of the newborn cerebral circulation and that endogenous CSE can produce sufficient H2S to decrease vascular tone. H2S appears to be a physiologically significant dilator in the cerebral circulation. PMID:21131483

Parfenova, Helena; Basuroy, Shyamali; Jaggar, Jonathan H.; Umstot, Edward S.; Fedinec, Alexander L.

2011-01-01

153

Design and synthesis of polymeric hydrogen sulfide donors.  

PubMed

Hydrogen sulfide (H2S) is a gaseous signaling molecule that has several important biological functions in the human body. Because of the difficulties of handling H2S gas, small organic compounds that release H2S under physiological conditions have been developed. The observed bioactivities of these H2S donors have generally been directly correlated with their H2S release properties. However, apart from H2S release, these H2S donors also exert biological effects by direct interaction with intracellular components within the cytoplasm after passive diffusion across cellular membranes. Here we report polymeric H2S donors based on ADT-OH which would alter cellular trafficking of ADT-OH to minimize the unfavorable interactions with intracellular components. We designed and synthesized a poly(ethylene glycol)-ADT (PEG-ADT) conjugate having ADT linked via an ether bond. Whereas ADT-OH significantly reduced cell viability in murine macrophages, the PEG-ADT conjugate did not show obvious cytotoxicity. The PEG-ADT conjugate released H2S in murine macrophages but not in the presence of serum proteins. The PEG-ADT conjugate was taken up by the cell through the endocytic pathway and stayed inside endolysosomes, which is different from the small amphiphilic donor ADT-OH that can directly enter the cytoplasm. Furthermore, PEG-ADT was capable of potentiating LPS-induced inflammation. This polymeric H2S donor approach may help to better understand the H2S bioactivities of the H2S donor ADT-OH. PMID:24942989

Hasegawa, Urara; van der Vlies, André J

2014-07-16

154

Hydrogen sulfide mitigates transition from compensatory hypertrophy to heart failure  

PubMed Central

We reported previously that although there is disruption of coordinated cardiac hypertrophy and angiogenesis in transition to heart failure, matrix metalloproteinase (MMP)-9 induced antiangiogenic factors play a vital role in this process. Previous studies have shown the cardioprotective role of hydrogen sulfide (H2S) in various cardiac diseases, but its role during transition from compensatory hypertrophy to heart failure is yet to be unveiled. We hypothesize that H2S induces MMP-2 activation and inhibits MMP-9 activation, thus promoting angiogenesis, and mitigates transition from compensatory cardiac hypertrophy to heart failure. To verify this, aortic banding (AB) was created to mimic pressure overload in wild-type (WT) mice, which were treated with sodium hydrosulfide (NaHS, H2S donor) in drinking water and compared with untreated control mice. Mice were studied at 3 and 8 wk. In the NaHS-treated AB 8 wk group, the expression of MMP-2, CD31, and VEGF was increased while the expression of MMP-9, endostatin, angiostatin, and tissue inhibitor of matrix metalloproteinase (TIMP)-3 was decreased compared with untreated control mice. There was significant reduction in fibrosis in NaHS-treated groups. Echocardiograph and pressure-volume data revealed improvement of cardiac function in NaHS-treated groups over untreated controls. These results show that H2S by inducing MMP-2 promotes VEGF synthesis and angiogenesis while it suppresses MMP-9 and TIMP-3 levels, inhibits antiangiogenic factors, reduces intracardiac fibrosis, and mitigates transition from compensatory hypertrophy to heart failure. PMID:21233344

Givvimani, Srikanth; Munjal, Charu; Gargoum, Riyad; Sen, Utpal; Tyagi, Neetu; Vacek, Jonathan C.

2011-01-01

155

MET2 affects production of hydrogen sulfide during wine fermentation.  

PubMed

The production of hydrogen sulfide (H2S) during yeast fermentation contributes negatively to wine aroma. We have mapped naturally occurring mutations in commercial wine strains that affect production of H2S. A dominant R310G mutant allele of MET2, which encodes homoserine O-acetyltransferase, is present in several wine yeast strains as well as in the main lab strain S288c. Reciprocal hemizygosity and allele swap experiments demonstrated that the MET2 R310G allele confers reduced H2S production. Mutations were also identified in genes encoding the two subunits of sulfite reductase, MET5 and MET10, which were associated with reduced H2S production. The most severe of these, an allele of MET10, showed five additional phenotypes: reduced growth rate on sulfate, elevated secretion of sulfite, and reduced production in wine of three volatile sulfur compounds: methionol, carbon disulfide and methylthioacetate. Alleles of MET5 and MET10, but not MET2, affected H2S production measured by colour assays on BiGGY indicator agar, but MET2 effects were seen when bismuth was added to agar plates made with Sauvignon blanc grape juice. Collectively, the data are consistent with the hypothesis that H2S production during wine fermentation results predominantly from enzyme activity in the sulfur assimilation pathway. Lower H2S production results from mutations that reduce the activity of sulfite reductase, the enzyme that produces H2S, or that increase the activity of L-homoserine-O-acetyltransferase, which produces substrate for the next step in the sulfur assimilation pathway. PMID:24841117

Huang, Chien; Roncoroni, Miguel; Gardner, Richard C

2014-08-01

156

Intermittent control procedures for the Geysers hydrogen sulfide emission abatement  

SciTech Connect

Pacific Gas and Electric Company (PG and E) operates the world's largest geothermal steam electric power generation facility, currently about 1.140 megawatts (Mw). This facility is located about 80 miles north of San Francisco, California and is within a region referred to as the Known Geothermal Resource Area (KGRA). Pollutants resulting from this method of electric power generation are due to impurities in the geothermal steam. A major contaminate in the steam is hydrogen sulfide (H/sub 2/S), a regulated pollutant in California. The ambient air quality standard (AAQS) for this pollutant in California is 0.03 parts per million (ppM) averaged over one hour. H/sub 2/S is an invisible, unpleasant smelling gas present in varying concentrations in the geothermal steam. Its odor has been compared to the smell of rotten eggs. Since PG and E is increasingly relying on this source of electrical power generation, it has committed millions of dollars to the development, testing, acquisition, and installation of abatement equipment to reduce H/sub 2/S emissions during the past ten years. In order to reduce the number of exceeds of the AAQS during this developmental period, a predictive model was needed for interim abatement purposes. Most of the high hourly H/sub 2/S values occur with meteorological conditions having poor ventilation resulting from a combination of low wind speed and reduced mixing layer depths. This weather condition is most common during the months of June through October in California. A predictive model was developed from three years of hourly H/sub 2/S measurements of 0.03 ppM or greater in populated areas downwind of the generation facility and from observations of associated meteorological data.

Buick, B.D.; Mooney, M.L.

1984-01-01

157

Single Membrane Reactor Configuration for Separation of Hydrogen, Carbon Dioxide and Hydrogen Sulfide  

SciTech Connect

The objective of the project was to develop a novel complementary membrane reactor process that can consolidate two or more downstream unit operations of a coal gasification system into a single module for production of a pure stream of hydrogen and a pure stream of carbon dioxide. The overall goals were to achieve higher hydrogen production efficiencies, lower capital costs and a smaller overall footprint than what could be achieved by utilizing separate components for each required unit process/operation in conventional coal-to-hydrogen systems. Specifically, this project was to develop a novel membrane reactor process that combines hydrogen sulfide removal, hydrogen separation, carbon dioxide separation and water-gas shift reaction into a single membrane configuration. The carbon monoxide conversion of the water-gas-shift reaction from the coal-derived syngas stream is enhanced by the complementary use of two membranes within a single reactor to separate hydrogen and carbon dioxide. Consequently, hydrogen production efficiency is increased. The single membrane reactor configuration produces a pure H{sub 2} product and a pure CO{sub 2} permeate stream that is ready for sequestration. This project focused on developing a new class of CO{sub 2}-selective membranes for this new process concept. Several approaches to make CO{sub 2}-selective membranes for high-temperature applications have been tested. Membrane disks using the technique of powder pressing and high temperature sintering were successfully fabricated. The powders were either metal oxide or metal carbonate materials. Experiments on CO{sub 2} permeation testing were also performed in the temperature range of 790 to 940 C for the metal carbonate membrane disks. However, no CO{sub 2} permeation rate could be measured, probably due to very slow CO{sub 2} diffusion in the solid state carbonates. To improve the permeation of CO{sub 2}, one approach is to make membranes containing liquid or molten carbonates. Several different types of dual-phase membranes were fabricated and tested for their CO{sub 2} permeation in reducing conditions without the presence of oxygen. Although the flux was quite low, on the order of 0.01-0.001 cc STP/cm{sup 2}/min, the selectivity of CO{sub 2}/He was almost infinite at temperatures of about 800 C. A different type of dual-phase membrane prepared by Arizona State University (ASU) was also tested at GTI for CO{sub 2} permeation. The measured CO{sub 2} fluxes were 0.015 and 0.02 cc STP/cm{sup 2}/min at 750 and 830 C, respectively. These fluxes were higher than the previous flux obtained ({approx}0.01 cc STP/cm{sup 2}/min) using the dual-phase membranes prepared by GTI. Further development in membrane development should be conducted to improve the CO{sub 2} flux. ASU has also focused on high temperature permeation/separation experiments to confirm the carbon dioxide separation capabilities of the dual-phase membranes with La{sup 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (LSCF6482) supports infiltrated with a Li/Na/K molten carbonate mixture (42.5/32.5/25.0 mole %). The permeation experiments indicated that the addition of O{sub 2} does improve the permeance of CO{sub 2} through the membrane. A simplified membrane reactor model was developed to evaluate the performance of the process. However, the simplified model did not allow the estimation of membrane transport area, an important parameter for evaluating the feasibility of the proposed membrane reactor technology. As a result, an improved model was developed. Results of the improved membrane reactor model show that the membrane shift reaction has promise as a means to simplify the production of a clean stream of hydrogen and a clean stream of carbon dioxide. The focus of additional development work should address the large area required for the CO{sub 2} membrane as identified in the modeling calculations. Also, a more detailed process flow diagram should be developed that includes integration of cooling and preheating feed streams as well as particulate removal so that stea

Micheal Roberts; Robert Zabransky; Shain Doong; Jerry Lin

2008-05-31

158

Direct chlorination process for geothermal power plant off-gas - hydrogen sulfide abatement  

SciTech Connect

The Direct Chlorination Process removes hydrogen sulfide from geothermal off-gases by reacting hydrogen sulfide with chlorine in the gas phase. Hydrogen chloride and elemental sulfur are formed by this reaction. The Direct Chlorination Process has been successfully demonstrated by an on-site operation of a pilot plant at the 3 M We HPG-A geothermal power plant in the Puna District on the island of Hawaii. Over 99.5 percent hydrogen sulfide removal was achieved in a single reaction state. Chlorine gas did not escape the pilot plant, even when 90 percent excess chlorine gas was used. A preliminary economic evaluation of the Direct Chlorination Process indicates that it is very competitive with the Stretford Process. Compared to the Stretford Process, the Direct Chlorination Process requires about one-third the initial capital investment and about one-fourth the net daily expenditure.

Sims, A.V.

1983-06-01

159

Extracellular transsulfuration generates hydrogen sulfide from homocysteine and protects endothelium from redox stress  

PubMed Central

Homocysteine, a cardiovascular and neurocognitive disease risk factor, is converted to hydrogen sulfide, a cardiovascular and neuronal protectant, through the transsulfuration pathway. Given the damaging effects of free homocysteine in the blood and the importance of blood homocysteine concentration as a prognosticator of disease, we tested the hypotheses that the blood itself regulates homocysteine-hydrogen sulfide metabolism through transsulfuration and that transsulfuration capacity and hydrogen sulfide availability protect the endothelium from redox stress. Here we show that the transsulfuration enzymes, cystathionine ?-synthase and cystathionine ?-lyase, are secreted by microvascular endothelial cells and hepatocytes, circulate as members of the plasma proteome, and actively produce hydrogen sulfide from homocysteine in human blood. We further demonstrate that extracellular transsulfuration regulates cell function when the endothelium is challenged with homocysteine and that hydrogen sulfide protects the endothelium from serum starvation and from hypoxia-reoxygenation injury. These novel findings uncover a unique set of opportunities to explore innovative clinical diagnostics and therapeutic strategies in the approach to homocysteine-related conditions such as atherosclerosis, thrombosis, and dementia. PMID:20817827

Beard, Richard S.; Pfau, Jean C.

2010-01-01

160

Effect of Hydrogen Sulfide on Cyclic AMP Production in Isolated Bovine and Porcine Neural Retinae  

Microsoft Academic Search

Hydrogen sulfide (H2S) has been reported to exert pharmacological effects on neural and non-neural tissues from several mammalian species. In\\u000a the present study, we examined the role of the intracellular messenger, cyclic AMP in retinal response to H2S donors, sodium hydrosulfide (NaHS) and sodium sulfide (Na2S) in cows and pigs. Isolated bovine and porcine neural retinae were incubated in oxygenated

Ya Fatou Njie-Mbye; Odelia Y. N. Bongmba; Chinwe C. Onyema; Abhishek Chitnis; Madhura Kulkarni; Catherine A. Opere; Angela M. LeDay; Sunny E. Ohia

2010-01-01

161

Hydrogen on unsupported ruthenium sulfide: Thermodesorption and [sup 1]H NMR studies  

SciTech Connect

The interaction of transition metal sulfides with hydrogen is a complex process. Understanding this process is important due to the very large number of industrial processes dealing with these systems. The main utilization of these catalysts concerns catalytic hydrotreating which involves hydrogenation reactions and C-S, C-N, and C-O bond cleavage reactions carried out in the presence of high partial pressures of hydrogen. The complexity of the interaction of hydrogen with metal sulfides is related to its double role, as reactant and as modifier of the concentration of active sites. As a matter of fact, the interaction of hydrogen with the surface of the catalyst provokes its partial reduction, leading to coordinatively unsaturated metal ions which are directly involved in the adsorptive and catalytic properties. To tackle this fundamental problem of hydrogen adsorption on ruthenium sulfide, the authors have taken the fully sulfided state as starting point and evaluated the influence of progressive desulfurization on the amount of adsorbed hydrogen. The nature of the adsorbed species was investigated using thermodesorption and [sup 1]H NMR. 20 refs., 3 figs.

Lacroix, M.; Yuan, S.; Breysse, M. (Institut de Recherches sur la Catalyse, Villeurbanne (France)); Doremieux-Morin, C.; Fraissard, J. (Universite Piere et Marie Curie, Paris (France))

1992-11-01

162

Effect of ambient hydrogen sulfide on the physical properties of vacuum evaporated thin films of zinc sulfide  

NASA Astrophysics Data System (ADS)

Evaporated thin films of zinc sulfide (ZnS) have been deposited in a low ambient atmosphere of hydrogen sulfide (H 2S ˜10 -4 Torr). The H 2S atmosphere was obtained by a controlled thermal decomposition of thiourea [CS(NH 2) 2] inside the vacuum chamber. It has been observed that at elevated substrates temperature of about 200 °C helps eject any sulfur atoms deposited due to thermal decomposition of ZnS during evaporation. The zinc ions promptly recombine with H 2S to give better stoichiometry of the deposited films. Optical spectroscopy, X-ray diffraction patterns and scanning electron micrographs depict the better crystallites and uniformity of films deposited by this technique. These deposited films were found to be more adherent to the substrates and are pinhole free, which is a very vital factor in device fabrication.

Singh, Beer Pal; Singh, Virendra; Tyagi, R. C.; Sharma, T. P.

163

Hydrogenation of sulfoxides to sulfides under mild conditions using ruthenium nanoparticle catalysts.  

PubMed

The first demonstration of the hydrogenation of sulfoxides under atmospheric H2 pressure is reported. The highly efficient reaction is facilitated by a heterogeneous Ru nanoparticle catalyst. The mild reaction conditions enable the selective hydrogenation of a wide range of functionalized sulfoxides to the corresponding sulfides. The high redox ability of RuO(x) nanoparticles plays a key role in the hydrogenation. PMID:25087622

Mitsudome, Takato; Takahashi, Yusuke; Mizugaki, Tomoo; Jitsukawa, Koichiro; Kaneda, Kiyotomi

2014-08-01

164

Methanol and hydrogen sulfide in comet P/Halley  

NASA Technical Reports Server (NTRS)

The Neutral Mass Spectrometer on the Giotto spacecraft measured the gas and ion composition in the coma of comet P/Halley. A detailed model of the ion chemistry inside the contact surface located at 4660 km is used to interpret the measured ion desnity profiles in the 32 to 35 amu/e mass range. The masses 33 and 35 amu/e are dominated by the protonated methanol and hydrogen sulfide ions CH3OH2(+) and H3S(+). Both profiles are essentially compatible with CH3OH and H2S originating from the nucleus only. The production rates relative to water are Y(CH3OH) = Q(CH3OH)/Q(H2O) = 1.7% and Y(H2S) = 0.41%. Our Y(CH3OH) agrees well with a determination from IR spectra obtained about 6 weeks after the Giotto encounter with P/Halley. In 7 other comets IR and microwave observations give Y(CH3OH) values between about 0.7 and 6%, indicating that the methanol abundance shows a strong variability from comet to comet. In three other comets Y(H2S) values between 0.2 and 0.5% have been reported. In addition to H2S(+), only ions containing minor isotopes of H, C, O and S contribute to mass 34 amu/e (e.g. (34)S(+), (13)CH3OH2(+), CH4DO(+)). These contributions can be calculated from the measured densities of the ions containing the major isotopes and the H2S(+) contribution from the measured H3S(+) density. From mass 34 amu/e we can also derive an upper limit of 1% for the abundance of deuterated methanol. This limit is at most marginally compatible with a direct interstellar origin of the CH3OH in P/Halley as the measured interstellar abundance of deuterated methanol is 1 to 6%.

Eberhardt, P.; Meier, R.; Krankowsky, D.; Hodges, R. R.

1994-01-01

165

Gas-sensitive properties of thin tin dioxide films under the influence of hydrogen sulfide  

NASA Astrophysics Data System (ADS)

In order to develop sensors for selective detection of hydrogen sulfide in the air, the characteristics of thin SnO2 films with various additives (Au, Pt) in the volume and deposited catalysts (Pt / Pd, Au) are studied. The films were obtained by magnetron sputtering. The sensor response to H2S (the ratio of the sensor conductivity G1 in the presence of hydrogen sulfide in the gas to the conductivity G0 in the clean air) is studied as a function of the operating temperature and gas concentration in the range 0.1-70 ppm. It is shown that the sensors with the addition of gold in the volume can be used to detect maximum permissible concentrations (7 ppm) of hydrogen sulfide in the working area after stabilization of the characteristics during long-term tests.

Sevast'yanov, E. Yu.; Maksimova, N. K.; Chernikov, E. V.; Firsov, A. A.

2012-11-01

166

Hydrogen sulfide clathrate hydrate FTIR spectroscopy: A help gas for clathrate formation in the Solar System?  

NASA Astrophysics Data System (ADS)

Clathrate hydrates may affect the stability and evolution of volatile species in comets and planets. Among abundant volatiles species, hydrogen sulfide forms one of the most stable clathrate hydrate and may play a major role in the initiation of the clathration process, as well as significantly affect the fraction of each volatiles species encaged in the clathrate structure with respect to the initial gaseous reservoir. In this study we investigate the hydrogen sulfide clathrate hydrate infrared signatures. Several pure and co-mixed hydrogen sulfide clathrate hydrates are produced and analyzed by infrared spectroscopy. The H2S clathrate hydrate specific vibrational transitions are recorded for an potential future search in planetary science and astrophysics, and its role as a clathrate hydrate promoter addressed.

Dartois, E.; Duret, Ph.; Marboeuf, U.; Schmitt, B.

2012-08-01

167

Computational study of the interaction of indole-like molecules with water and hydrogen sulfide  

NASA Astrophysics Data System (ADS)

The characteristics of the interaction between water and hydrogen sulfide with indole and a series of analogs obtained by substituting the NH group of indole by different heteroatoms have been studied by means of ab initio calculations. In all cases, minima were found corresponding to structures where water and hydrogen sulfide interact by means of X-H...? contacts. The interaction energies for all these ? complexes are quite similar, spanning from -13.5 to -18.8 kJ/mol, and exhibiting the stability sequence NH > CH2 ? PH > Se ? S > O, for both water and hydrogen sulfide. Though interaction energies are similar, hydrogen sulfide complexes are slightly favored over their water counterparts when interacting with the ? cloud. ?-Type complexes were also considered for the systems studied, but only in the case of water complexes this kind of complexes is relevant. Only for complexes formed by water and indole, a significantly more stable ?-type complex was found with an interaction energy amounting to -23.6 kJ/mol. Oxygen and phosphorous derivatives also form ?-type complexes of similar stability as that observed for ? ones. Despite the similar interaction energies exhibited by complexes with water and hydrogen sulfide, the nature of the interaction is very different. For ? complexes with water the main contributions to the interaction energy are electrostatic and dispersive contributing with similar amounts, though slightly more from electrostatics. On the contrary, in hydrogen sulfide complexes dispersion is by far the main stabilizing contribution. For the ?-type complexes, the interaction is clearly dominated by the electrostatic contribution, especially in the indole-water complex.

Cabaleiro-Lago, Enrique M.; Rodríguez-Otero, Jesús; Peña-Gallego, Ángeles

2011-10-01

168

Hydrogen sulfide production and volatilization in a polymictic eutrophic saline lake, Salton Sea, California.  

PubMed

The Salton Sea is a large shallow saline lake located in southern California that is noted for high sulfate concentrations, substantial algal productivity, and very warm water column temperatures. These conditions are well-suited for sulfide production, and sulfide has been implicated in summer fish kills, although no studies have been conducted to specifically understand hydrogen sulfide production and volatilization there. Despite polymictic mixing patterns and relatively short accumulation periods, the amount of sulfide produced is comparable to meromictic lakes. Sulfide levels in the Salton Sea reached concentrations of 1.2 mmol L(-1) of total free sulfide in the hypolimnion and 5.6 mmol L(-1) in the sediment pore water. Strong winds in late July mixed H2S into the surface water, where it depleted the entire water column of dissolved oxygen and reached a concentration of 0.1 mmol L(-1). Sulfide concentrations exceeded the toxicity threshold of tilapia (Oreochromis mossambicus) and combined with strong anoxia throughout the water column, resulted in a massive fish kill. The mixing of sulfide into the surface waters also increased atmospheric H2S concentrations, reaching 1.0 micromol m(-3). The flux of sulfide from the sediment into the water column was estimated to range from 2-3 mmol m(-2) day(-1) during the winter and up to 8 mmol m(-2) day(-1) during the summer. Application of the two-layer model for volatilization indicates that up to 19 mmol m(-2) day(-1) volatilized from the surface during the mixing event. We estimate that as much as 3400 Mg year(-1) or approximately 26% of sulfide that diffused into the water column from the deepest sediments may have been volatilized to the atmosphere. PMID:18760446

Reese, Brandi Kiel; Anderson, Michael A; Amrhein, Christopher

2008-11-15

169

Hydrogen sulfide in plants: from dissipation of excess sulfur to signaling molecule.  

PubMed

Sulfur is essential in all organisms for the synthesis of amino acids cysteine and methionine and as an active component of numerous co-factors and prosthetic groups. However, only plants, algae, fungi, and some prokaryotes are capable of using the abundant inorganic source of sulfur, sulfate. Plants take sulfate up, reduce it, and assimilate into organic compounds with cysteine being the first product of the pathway and a donor of reduced sulfur for synthesis of other S-containing compounds. Cysteine is formed in a reaction between sulfide, derived from reduction of sulfite and an activated amino acid acceptor, O-acetylserine. Sulfide is thus an important intermediate in sulfur metabolism, but numerous other functions in plants has been revealed. Hydrogen sulfide can serve as an alternative source of sulfur for plants, which may be significant in anaerobic conditions of waterlogged soils. On the other hand, emissions of hydrogen sulfide have been detected from many plant species. Since the amount of H2S discharged correlated with sulfate supply to the plants, the emissions were considered a mechanism for dissipation of excess sulfur. Significant hydrogen sulfide emissions were also observed in plants infected with pathogens, particularly with fungi. H2S thus seems to be part of the widely discussed sulfur-induced-resistance/sulfur-enhanced-defense. Recently, however, more evidence has emerged for a role for H2S in regulation and signaling. Sulfide stabilizes the cysteine synthase complex, increasing so the synthesis of its acceptor O-acetylserine. H2S has been implicating in regulation of plant stress response, particularly draught stress. There are more and more examples of processes regulated by H2S in plants being discovered, and hydrogen sulfide is emerging as an important signaling molecule, similar to its role in the animal and human world. How similar the functions, and homeostasis of H2S are in these diverse organisms, however, remains to be elucidated. PMID:24582856

Calderwood, Alexander; Kopriva, Stanislav

2014-09-15

170

Oxidation of sulfides to sulfoxides and sulfones with 30% hydrogen peroxide under organic solvent- and halogen-free conditions  

Microsoft Academic Search

Aromatic and aliphatic sulfides are oxidized to sulfoxides or sulfones in high yield with 30% hydrogen peroxide under organic solvent- and halogen-free conditions. Dialkyl and alkyl aryl sulfides are cleanly oxidized to sulfoxides using aqueous hydrogen peroxide without catalysts. The best catalyst for the sulfone synthesis consists of sodium tungstate, phenylphosphonic acid, and methyltrioctylammonium hydrogensulfate. Co-existing primary or secondary alcohol

Kazuhiko Sato; Mamoru Hyodo; Masao Aoki; Xiao-Qi Zheng; Ryoji Noyori

2001-01-01

171

Motion of the concentration front in catalytic oxidation of hydrogen sulfide to condensed sulfur in a fixed bed  

Microsoft Academic Search

An unsteady-state mathematical model for condensed sulfur formation by catalytic hydrogen sulfide oxidation in a fixed catalyst bed is proposed. Analytical solutions for the model are obtained. The steady-state front of hydrogen sulfide oxidation is shown to occur. The front velocity, the time of front formation, and the effect of the catalyst activity on front formation are estimated. The analytical

V. M. Khanaev; G. G. Kuvshinov; O. N. Kovalenko

1996-01-01

172

30 CFR 550.245 - What hydrogen sulfide (H2S) information must accompany the DPP or DOCD?  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false What hydrogen sulfide (H2S) information must accompany...DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL...Documents (docd) § 550.245 What hydrogen sulfide (H2 S) information must...

2012-07-01

173

30 CFR 250.245 - What hydrogen sulfide (H2S) information must accompany the DPP or DOCD?  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false What hydrogen sulfide (H2S) information must accompany...DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL...Documents (docd) § 250.245 What hydrogen sulfide (H2S) information must...

2011-07-01

174

30 CFR 250.245 - What hydrogen sulfide (H2S) information must accompany the DPP or DOCD?  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false What hydrogen sulfide (H2S) information must accompany...DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL...Documents (docd) § 250.245 What hydrogen sulfide (H2S) information must...

2010-07-01

175

30 CFR 550.245 - What hydrogen sulfide (H2S) information must accompany the DPP or DOCD?  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false What hydrogen sulfide (H2S) information must accompany...DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL...Documents (docd) § 550.245 What hydrogen sulfide (H2 S) information must...

2013-07-01

176

30 CFR 550.245 - What hydrogen sulfide (H2S) information must accompany the DPP or DOCD?  

...2014-07-01 2014-07-01 false What hydrogen sulfide (H2S) information must accompany...DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL...Documents (docd) § 550.245 What hydrogen sulfide (H2 S) information must...

2014-07-01

177

Silicate melt removal and sulfide liquid retention in ultramafic rocks of the Duke Island Complex, Southeastern Alaska  

NASA Astrophysics Data System (ADS)

Magmatic Ni-Cu-PGE sulfide mineralization occurs within olivine clinopyroxenite, hornblende-bearing clinopyroxenite, and magnetite-hornblende-rich rocks in the Ural-Alaskan-Type Duke Island Complex in Southeast Alaska. The addition of large amounts of sulfur from country rocks occurred during fractional crystallization of the parental magma when clinopyroxene was becoming a liquidus mineral. Textural interfaces between sulfide and silicate minerals are strongly interlobate, and differ significantly from net-textures that are developed in many Ni-Cu-PGE deposits. Sulfide-free olivine clinopyroxenite is an adcumulate; residual liquid was efficiently expelled from the accumulating crystal pile. A significant interstitial liquid component is observable only in the form of interstitial sulfide in the S-rich rocks. Rounded sulfide inclusions and blebby to vermicular sulfide-silicate intergrowths indicate that silicate crystallization occurred under conditions of sulfide saturation. The presence of dense sulfide liquid inhibited the growth of silicate minerals and led to the development of interlobate grain boundaries. Strong, localized wetting of sulfide liquids on crystallizing silicates, and downward percolation of sulfide liquid through a crystallizing mush may have contributed to the evolution of these textures. Residual silicate liquid was removed from the system due to a combination of buoyant advection and compaction, but dense sulfide liquid remained.

Stifter, Eric C.; Ripley, Edward M.; Li, Chusi

2014-10-01

178

Characterization of a Novel, Water-Soluble Hydrogen Sulfide-Releasing Molecule (GYY4137) New Insights Into the Biology of Hydrogen Sulfide  

Microsoft Academic Search

Background—The potential biological significance of hydrogen sulfide (H2S) has attracted growing interest in recent years. The aim of this study was to characterize a novel, water-soluble, slow-releasing H2S compound (morpholin-4-ium 4 methoxyphenyl(morpholino) phosphinodithioate (GYY4137)) and evaluate its use as a tool to investigate the cardiovascular biology of this gas. Methods and Results—The acute vasorelaxant effect of drugs was assessed in

Ling Li; Matthew Whiteman; Yan Yi Guan; Kay Li Neo; Yvonne Cheng; Shiau Wei Lee; Yujun Zhao; Rajamanian Baskar; Choon-Hong Tan; Philip K. Moore

179

The Response of Caenorhabditis elegans to Hydrogen Sulfide and Hydrogen Cyanide  

PubMed Central

Hydrogen sulfide (H2S), an endogenously produced small molecule, protects animals from various stresses. Recent studies demonstrate that animals exposed to H2S are long lived, resistant to hypoxia, and resistant to ischemia–reperfusion injury. We performed a forward genetic screen to gain insights into the molecular mechanisms Caenorhabditis elegans uses to appropriately respond to H2S. At least two distinct pathways appear to be important for this response, including the H2S-oxidation pathway and the hydrogen cyanide (HCN)-assimilation pathway. The H2S-oxidation pathway requires two distinct enzymes important for the oxidation of H2S: the sulfide:quinone reductase sqrd-1 and the dioxygenase ethe-1. The HCN-assimilation pathway requires the cysteine synthase homologs cysl-1 and cysl-2. A low dose of either H2S or HCN can activate hypoxia-inducible factor 1 (HIF-1), which is required for C. elegans to respond to either gas. sqrd-1 and cysl-2 represent the entry points in the H2S-oxidation and HCN-assimilation pathways, respectively, and expression of both of these enzymes is highly induced by HIF-1 in response to both H2S and HCN. In addition to their role in appropriately responding to H2S and HCN, we found that cysl-1 and cysl-2 are both essential mediators of innate immunity against fast paralytic killing by Pseudomonas. Furthermore, in agreement with these data, we showed that growing worms in the presence of H2S is sufficient to confer resistance to Pseudomonas fast paralytic killing. Our results suggest the hypoxia-independent hif-1 response in C. elegans evolved to respond to the naturally occurring small molecules H2S and HCN. PMID:21840852

Budde, Mark W.; Roth, Mark B.

2011-01-01

180

Exposure to hydrogen sulfide, mercaptans and sulfur dioxide in pulp industry.  

PubMed

An hygienic survey for hydrogen sulfide, methyl mercaptan and its derivatives and sulfur dioxide in kraft mills and in sulfite mills revealed concentrations varying from 0 to 20 ppm hydrogen sulfide, 0 to 15 ppm methyl mercaptan and comparable amounts of dimethyl sulfide with dimethyl disulfide up to 1.5 ppm. The greatest emissions were detected at chip chutes and evaporation vacuum pumps. Batch operations yielded clearly higher sulfur dioxide concentrations (up to 20 ppm) as compared to a continuous ammonia-base digester. Furthermore, there was a strong correlation with the season in the sulfite mills where higher concentrations were found in the winter when natural ventilation was poorer. As to the health effects, the exposed workers complained of headaches and a decrease in concentration capacity more often than matched controls. The number of sick leaves was greater in the exposed workers than among the controls. PMID:6517022

Kangas, J; Jäppinen, P; Savolainen, H

1984-12-01

181

[Regulation of sulfates, hydrogen sulfide and heavy metals in technogenic reservoirs by sulfate-reducing bacteria].  

PubMed

Sulfate-reducing bacteria Desulfovibrio desulfuricans Ya-11 in the presence of sulfates and organic compounds in the medium reduce sulfates to hydrogen sulfide (dissimilatory sulfate reduction). Heavy metals in concentration over 2 mM inhibit this process. Pb2+, Zn2+, Ni2+, Co2+, Fe2+ and Cd2+ ions in concentration 1-1.5 mM display insignificant inhibiting effect on sulfate reduction process, and metals precipitate in the form of sulfides. At concentrations of heavy metals 2-3 mM one can observe a decrease of sulfates reduction intensity, and a percent of metals binding does not exceed 72%. Obtained results give reason to confirm, that sulfate-reducing bacteria play an important role in regulation of the level of sulfates, hydrogen sulfide and heavy metals in reservoirs and they may be used for purification of water environment from these compounds. PMID:21598657

Hudz', S P; Peretiatko, T B; Moroz, O M; Hnatush, S O; Klym, I R

2011-01-01

182

The Role of Water for Photodecomposition of Aqueous Hydrogen Sulfide Using Stratified Photocatalyst--Experimental Part  

SciTech Connect

Splitting of hydrogen sulfide using sunlight is a useful reaction to produce hydrogen. Alkaline sulfide solution, which is prepared by dissolving hydrogen sulfide into alkaline water, is selected as the reaction medium of photocatalytic hydrogen generation reaction. In this system, the photocatalytic reaction is assumed to occur as follows: 2H{sub 2}O + 2e{sup -} {yields} H{sub 2} + 2OH{sup -} (1) 2S{sup 2-} + 2h{sup +} {yields} S{sub 2}{sup 2-} (2) However, as the reaction progresses white solids precipitate in the reaction medium. Furthermore, the HPLC analysis suggested that the ratio between the consumption of sulfide ion and the amount of hydrogen generation was about 3:2, which is not stoichiometric. Thus, in this paper, we characterized the white solid precipitate and tried to optimize the solution condition to prevent the precipitation of the same. From our study, the white solid precipitate was confirmed as sulfur derived from the oxidation of the disulfide ion. It was confirmed that the addition of sulfite ions prevented the oxidation of disulfide ions, which causes the precipitation. In the absence of sulfite ions and for sufide ion concentration less than 0.1M, the precipitation of sulfur occurs in a very short reaction time. On the other hand the hydrogen evolution rate retarded when the sulfide ion concentration is higher than 0.1M. This was due to the degradation of the stratified CdS particles. Thus, the optimal concentration of Na2S solution was determined to be around 0.1M.

Arai, Takeo; Shinoda, Kozo; Tohji, Kazuyuki [Graduate School of Environmental Studies, Tohoku University, Aramaki Aza Aoba 20, Aoba-Ku, Sendai 980-8579 (Japan); Matsumoto, Takatoshi [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aoba, Sendai 980-8577 (Japan); Sakima, Shuhei [Deptertment of Geoscience and Technology, Tohoku University, Aramaki Aza Aoba 01, Aoba-Ku, Sendai 980-8579 (Japan); Nagashima, Umpei [Grid Technology Research Center, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8568 (Japan)

2006-05-15

183

Title: Modeling of Syngas Reactions and Hydrogen Generation over Sulfides  

Microsoft Academic Search

The modeling research concentrated on hydrogen chemisorption and activation over various structural features of molybdenum disulfide, a hydrogenation catalyst used in applications such as hydrogenations of olefins and aromatics, hydrodesulfurization and hydrodenitrification, and in a bifunctional composite with alkali promoters, synthesis of oxygenates from oxides of carbon, primarily carbon monoxide to alcohols. Computational platforms involved all-electron density functional theory (DFT)

Michael Neiman; Qisheng Ma; Seeley G. Mudd

184

Electrochemical polishing of hydrogen sulfide from coal synthesis gas  

Microsoft Academic Search

An advanced process has been developed for the separation of H2S from coal gasification product streams through an electrochemical membrane. This technology is developed for use in coal gasification facilities providing fuel for cogeneration coal fired electrical power facilities and molten carbonate fuel cell (MCFC) electrical power facilities. H2S is removed from the syn-gas by reduction to the sulfide ion

S. R. Alexander; J. Winnick

1994-01-01

185

Electrochemical polishing of hydrogen sulfide from coal synthesis gas  

Microsoft Academic Search

An advanced process has been developed for the separation of HâS from coal gasification product streams through an electrochemical membrane. This technology is developed for use in coal gasification facilities providing fuel for cogeneration coal fired electrical power facilities and Molten Carbonate Fuel Cell electrical power facilities. HâS is removed from the syn-gas by reduction to the sulfide ion and

E. F. Gleason; J. Winnick

1995-01-01

186

Hydrogen sulfide oxidation and the arterial chemoreflex: effect of methemoglobin.  

PubMed

Endogenous H(2)S has been proposed to transduce the effects of hypoxia in the carotid bodies (CB). To test this hypothesis, we created a sink for endogenously produced H(2)S by inducing ?10% methemoglobinemia via the injection of 250 mg of sodium nitrite in spontaneously breathing anaesthetized sheep. Methemoglobinemia has been shown to catalyze the oxidation of large quantities of sulfide in the blood and tissues. We found that the presence of metHb completely abolished the ventilatory stimulation induced by 10 mg NaHS (i.v.), which in control conditions mimicked the effects of breathing 6-7 tidal volumes of nitrogen, confirming the dramatic increase in the oxidative power of the blood for sulfide. The ventilatory responses to hypoxia (10% O(2)), nitrogen and hyperoxia were in no way depressed by the metHb. Our results demonstrate that the ventilatory chemoreflex is not depressed in the presence of a high oxidative capacity for sulfide and challenge the view that H(2)S transduces the effects of hypoxia in the CB. PMID:21569867

Haouzi, Philippe; Bell, Harold; Philmon, Maeve

2011-08-15

187

Adsorbent characteristics of hydrogen sulfide and methyl mercaptan in single and mixed systems  

Microsoft Academic Search

The paper reports the results of an experimental study made on the changes in gas concentration and adsorption quantity, and in breakthrough (leakage of gas through broken adsorbent) curve at time of dynamic adsorption for the typical malodorous gases; hydrogen sulfide and methyl mercaptan co?existing in the exhaust gas in many waste treatment facilities both for single system (when these

Kazushige Hinokiyama; Konosuke Nishida; Masahiro Osako; Nobuo Muto

1991-01-01

188

Reaction of hydrogen sulfide with oxygen in the presence of sulfite  

SciTech Connect

Commonly, abatement of hydrogen sulfide emission from a geothermal powerplant requires that hydrogen sulfide dissolved in the cooling water be eliminated by chemical reaction. Oxidation by atmospheric oxygen is the preferred reaction, but requires a suitable catalyst. Nickel is the most potent and thereby cheapest catalyst for this purpose. One mg/L nickel in the cooling water would allow 99% removal of hydrogen sulfide to be attained. A major drawback of catalytic air oxidation is that colloidal sulfur is a major reaction product; this causes rapid sludge accumulation and deposition of sulfur scale. We studied the kinetics and product distribution of the reaction of hydrogen sulfide with oxygen, catalyzed by nickel. Adding sodium sulfite to the solution completely suppresses formation of colloidal sulfur by converting it to thiosulfate. The oxidation reaction is an autocatalytic, free radical chain reaction. A rate expression for this reaction and a detailed reaction mechanism were developed. Nickel catalyzes the chain initiation step, and polysulfidoradical ions propagate the chains. Several complexes of iron and cobalt were also studied. Iron citrate and iron N-hydroxyEDTA are the most effective iron based catalysts. Uncomplexed cobalt is as effective as nickel, but forms a precipitate of cobalt oxysulfide and is too expensive for practical use. 33 figures, 9 tables.

Weres, O.; Tsao, L.

1983-01-14

189

Hydrogenation of cyclopentadiene to cyclopentene on an alumina-palladium-sulfide catalyst  

SciTech Connect

It was found possible to carry out selective hydrogenation of cyclopentadiene to cyclopentene on alumina-palladium-sulfide catalyst (amount of Pd 0.2 wt.%) at increased pressure (0.5 MPa) and low temperature (300-310/sup 0/K). Process conditions enable cyclopentene of 99.99% purity to be obtained. 15 references, 5 figures, 5 tables.

Gagarin, S.G.; Makar'ev, S.S.; Krichko, A.A.

1982-01-01

190

Giant Hydrogen Sulfide Plume in the Oxygen Minimum Zone off Peru Supports Chemolithoautotrophy  

E-print Network

Giant Hydrogen Sulfide Plume in the Oxygen Minimum Zone off Peru Supports Chemolithoautotrophy , Julie LaRoche1,4 * 1 Research Division Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany, 2 Institute for General Microbiology, Christian-Albrechts- University, Kiel

Boyer, Edmond

191

Hydrogen Sulfide, a Toxic Gas with Cardiovascular Properties in Uremia: How Harmful Is It?  

Microsoft Academic Search

Hydrogen sulfide (H2S) is a poisonous gas which can be lethal. However, it is also produced endogenously, thus belonging to the family of gasotransmitters along with nitric oxide and carbon monoxide. H2S is in fact involved in mediating several signaling and cytoprotective functions, for example in the nervous, cardiovascular, and gastrointestinal systems, such as neuronal transmission, blood pressure regulation and

Alessandra F. Perna; Diana Lanza; Immacolata Sepe; Ilaria Raiola; Rosanna Capasso; Natale G. De Santo; Diego Ingrosso

2011-01-01

192

Effects of Hydrogen Sulfide on the Performance of a PEMFC R. Mohtadi,a,  

E-print Network

-products, such as carbon monoxide, ammonia, and hydrogen sulfide. While it is well known that H2S severely poisons Pt, Maryland 21921, USA An exploratory study of H2S poisoning of membrane electrode assemblies MEAs in proton experiments; (iii) in contrast to CO poisoning, Ru has no effect on increasing MEA tolerance toward H2S

Van Zee, John W.

193

PERGAMON Carbon 38 (2000) 17571765 High temperature hydrogen sulfide adsorption on activated  

E-print Network

temperature was examined as a2 function of carbon surface chemistry (oxidation, thermal desorption, and metalPERGAMON Carbon 38 (2000) 1757­1765 High temperature hydrogen sulfide adsorption on activated gas stream2 at a temperature of 5508C. The ability of activated carbon to remove H S at elevated

Cal, Mark P.

194

PERGAMON Carbon 38 (2000) 17671774 High temperature hydrogen sulfide adsorption on activated  

E-print Network

PERGAMON Carbon 38 (2000) 1767­1774 High temperature hydrogen sulfide adsorption on activated carbon II. Effects of gas temperature, gas pressure and sorbent regeneration 1 2 3 *M.P. Cal , B of activated carbon sorbents were evaluated for removal of H S at high temperatures (400­6008C) in an2

Cal, Mark P.

195

Hot Gas Removal of Tars, Ammonia, and Hydrogen Sulfide from Biomass Gasification Gas  

Microsoft Academic Search

Gasification of biomass is a promising source of fuels and other chemical products. However, the removal of tars, ammonia, hydrogen sulfide, and other byproducts from the raw gas is required. The gas clean?up technology that offers more advantages is hot catalytic gas conditioning downstream of the gasifier reactor. Here, we review the applications of basic, acidic, metallic, and redox catalysts

Walter Torres; Sourabh S. Pansare; James G. Goodwin Jr

2007-01-01

196

Hydrogen sulfide: from the smell of the past to the mediator of the future?  

Microsoft Academic Search

Gases such as nitric oxide and carbon monoxide play important roles both in normal physiology and in disease. In recent years, interest has been directed towards other naturally occurring gases, notably hydrogen sulfide (H2S), which is both a potent vasodilator and a mediator of long-term potentiation in the brain. This article focuses on recent work that suggests a role for

Philip K Moore; Madhav Bhatia; Shabbir Moochhala

2003-01-01

197

IRIS TOXICOLOGICAL REVIEW AND SUMMARY DOCUMENTS FOR HYDROGEN SULFIDE (EXTERNAL REVIEW DRAFT)  

EPA Science Inventory

Hydrogen sulfide (H2S) is a colorless gas with a strong odor of rotten eggs. Its primary uses include the production of elemental sulfur and sulfuric acid, the manufacture of heavy water and other chemicals. Occupational exposure occurs primarily from its presence in petroleum, n...

198

Desulfurization of gaseous fuels using activated carbons as catalysts for the selective oxidation of hydrogen sulfide  

Microsoft Academic Search

The removal of low concentrations of hydrogen sulfide (HâS) from hydrogen-rich gaseous fuels by selective catalytic oxidation, using activated carbon as the catalyst, was studied. The capacities of four activated carbons for reducing the HâS concentration down to the parts per billion (ppb) level were determined to be strongly related to their microstructures and impurities, even though their activity and

Xianxian Wu; Viviane Schwartz; Steven H. Overbury; Timothy R. Armstrong

2005-01-01

199

Evaluation of a quantitative screening method for hydrogen sulfide production by cheese-ripening microorganisms: The first step towards l-cysteine catabolism  

Microsoft Academic Search

A practical adaptation of the methylene blue reaction for hydrogen sulfide quantification was developed to perform microbial selection. Closed plate flasks containing a zinc-agar layer above the liquid microbial culture are proposed as a trap system where the H2S can be retained and then quantified by the methylene blue reaction. Using this quantitative method, the ability to produce H2S was

M. Lopez del Castillo Lozano; R. Tâche; P. Bonnarme; S. Landaud

2007-01-01

200

Precipitation of heavy metals from coal ash leachate using biogenic hydrogen sulfide generated from FGD gypsum.  

PubMed

Investigations were undertaken to utilize flue gas desulfurization (FGD) gypsum for the treatment of leachate from the coal ash (CA) dump sites. Bench-scale investigations consisted of three main steps namely hydrogen sulfide (H(2)S) production by sulfate reducing bacteria (SRB) using sulfate from solubilized FGD gypsum as the electron acceptor, followed by leaching of heavy metals (HMs) from coal bottom ash (CBA) and subsequent precipitation of HMs using biologically produced sulfide. Leaching tests of CBA carried out at acidic pH revealed the existence of several HMs such as Cd, Cr, Hg, Pb, Mn, Cu, Ni and Zn. Molasses was used as the electron donor for the biological sulfate reduction (BSR) process which produced sulfide rich effluent with concentration up to 150 mg/L. Sulfide rich effluent from the sulfate reduction process was used to precipitate HMs as metal sulfides from CBA leachate. HM removal in the range from 40 to 100% was obtained through sulfide precipitation. PMID:23168629

Jayaranjan, Madawala Liyanage Duminda; Annachhatre, Ajit P

2013-01-01

201

Use of AERMOD to determine a hydrogen sulfide emission factor for swine operations by inverse modeling  

NASA Astrophysics Data System (ADS)

This study was conducted to determine both optimal settings applied to the plume dispersion model, AERMOD, and a scalable emission factor for accurately determining the spatial distribution of hydrogen sulfide concentrations in the vicinity of swine concentrated animal feeding operations (CAFOs). These operations emit hydrogen sulfide from both housing structures and waste lagoons. With ambient measurements made at 4 stations within 1 km of large swine CAFOs in Iowa, an inverse-modeling approach applied to AERMOD was used to determine hydrogen sulfide emission rates. CAFO buildings were treated as volume sources whereas nearby lagoons were modeled as area sources. The robust highest concentration (RHC), calculated for both measured and modeled concentrations, was used as the metric for adjusting the emission rate until the ratio of the two RHC levels was unity. Utilizing this approach, an average emission flux rate of 0.57 ?g m -2 s -1 was determined for swine CAFO lagoons. Using the average total animal weight (kg) of each CAFO, an average emission factor of 6.06 × 10 -7 ?g yr -1 m -2 kg -1 was calculated. From studies that measured either building or lagoon emission flux rates, building fluxes, on a floor area basis, were considered equal to lagoon flux rates. The emission factor was applied to all CAFOs surrounding the original 4 sites and surrounding an additional 6 sites in Iowa, producing an average modeled-to-measured RHC ratio of 1.24. When the emission factor was applied to AERMOD to simulate the spatial distribution of hydrogen sulfide around a hypothetical large swine CAFO (1 M kg), concentrations within 0.5 km from the CAFO exceeded 25 ppb and dropped to 2 ppb within 6 km of the CAFO. These values compare to a level of 30 ppb that has been determined by the State of Iowa as a threshold level for ambient hydrogen sulfide levels.

O'Shaughnessy, Patrick T.; Altmaier, Ralph

2011-09-01

202

Automated detection of hydrogen sulfide release from thiosulfate by Salmonella spp.  

PubMed

Hydrogen sulfide production is used in conventional tests for identification and differentiation of Salmonella spp. from other species of Enterobacteriaceae, and a black precipitate on agar media is the indicator of the reaction. Selective liquid media were formulated for automated optical detection of H2S in salmonellae using the BioSys instrument. The media contained thiosulfate and ferric ammonium citrate, and production of H2S caused copious black pigmentation of the broth. Combination of the H2S indicators with dulcitol or xylose as fermentable carbohydrate, lysine, ornithine or arginine to induce decarboxylase activity, and Tergitol 4 as inhibitor selectively identified six Salmonella spp. by a sharp drop in transmittance at 585 nm. The time for detection of transmittance changes was inversely proportional to initial numbers of CFU in the media: 10 h for 10(5) CFU/ml and 17 h for 10(1) CFU/ml. No detection was observed in six non-Salmonella species of Enterobacteriaceae tested. PMID:9709237

Shelef, L A; Tan, W

1998-05-01

203

New Measurements of the Densities of Copper, Nickel, and Iron Sulfide Liquids  

NASA Astrophysics Data System (ADS)

Density measurements of sulfide liquids in the Fe-Ni-Cu-S-O system were performed from 1150°C-1250°C under controlled oxygen and sulfur fugacities. Measurements were made using the modified single bob (MSB) Archimedean method using zirconia ceramic bobs and crucibles. A 0.005mm resolution micrometer was attached to an elevator, which raised the crucible and melt relative to the free-hanging, stationary bob. A 0.001 g resolution analytical balance connected to a laptop computer continuously recorded the buoyancy as a function of crucible elevation. Densities were calculated by converting elevation to immersed volume and regressing the slope of buoyancy versus volume immersed. log(fO2) in the experiments ranged from -7.8 to -12.6 and log(fS2) ranged from -0.9 to -3.3. 38 successful sulfide liquid density measurements were performed, with values ranging from 3.8 g/cc to 6.6 g/cc. Regression of the resulting data suggests that a simple linear volume mixing model is adequate to represent the compositional dependence of density in copper- and nickel-sulfide liquids. A moderate positive excess mixing volume appears to be justified in iron-sulfide liquids. This result, along with high derived partial molar volumes for oxygen and sulfur components, are qualitatively consistent with the suggestion that increasing pressure will partition oxygen and sulfur out of the sulfide liquid during planetary accretion. The MSB density measurement also provides information on the relative magnitude of gas-zirconia and sulfide-zirconia surface energies. Assuming most of the observed variation results from sulfide chemistry it appears that oxidizing conditions significantly decrease sulfide-zirconia surface energies (increase wetting). If we can extrapolate this result to silicate minerals, this would suggest that oxidizing conditions will decrease wetting angle and thus increase the potential for sulfide segregation during planetary formation. We hope to test this hypothesis soon. Our experience suggests that trivial modifications to the apparatus used in this study may provide an effective and reliable method for measuring liquid-solid surface energies in both sulfide and silicate systems. Such data would prove useful in both melt percolation and bubble nucleation and growth calculations.

Mioduszewski, L.; Kress, V. C.

2005-12-01

204

Electrochemical polishing of hydrogen sulfide from coal synthesis gas  

SciTech Connect

An advanced process has been developed for the separation of H{sub 2}S from coal gasification product streams through an electrochemical membrane. This technology is developed for use in coal gasification facilities providing fuel for cogeneration coal fired electrical power facilities and Molten Carbonate Fuel Cell electrical power facilities. H{sub 2}S is removed from the syn-gas by reduction to the sulfide ion and H at the cathode. The sulfide ion migrates to the anode through a molten salt electrolyte suspended in an inert ceramic matrix. Once at the anode it is oxidized to elemental sulfur and swept away for condensation in an inert gas stream. The syn-gas is enriched with the H{sub 2}. Order-of-magnitude reductions in H{sub 2}S have been repeatably recorded (100 ppm to 10 ppm H{sub 2}S) on a single pass through the cell. This process allows removal of H{sub 2}S without cooling the gas stream and with negligible pressure loss through the separator. Since there are no absorbents used, there is no absorption/regeneration step as with conventional technology. Elemental sulfur is produced as a by-product directly, so there is no need for a Claus process for sulfur recovery. This makes the process economically attractive since it is much less equipment intensive than conventional technology.

Gleason, E.F.; Winnick, J.

1995-11-01

205

Method of removing hydrogen sulfide from gases utilizing a zinc oxide sorbent and regenerating the sorbent  

DOEpatents

A spent solid sorbent resulting from the removal of hydrogen sulfide from a fuel gas flow is regenerated with a steam-air mixture. The mixture of steam and air may also include additional nitrogen or carbon dioxide. The gas mixture contacts the spent sorbent containing metal sulfide at a temperature above 500.degree. C. to regenerate the sulfide to metal oxide or carbonate. Various metal species including the period four transition metals and the lanthanides are suitable sorbents that may be regenerated by this method. In addition, the introduction of carbon dioxide gas permits carbonates such as those of strontium, barium and calcium to be regenerated. The steam permits regeneration of spent sorbent without formation of metal sulfate. Moreover, the regeneration will proceed with low oxygen concentrations and will occur without the increase in temperature to minimize the risk of sintering and densification of the sorbent.

Jalan, Vinod M. (Concord, MA); Frost, David G. (Maynard, MA)

1984-01-01

206

Hydrogen Sulfide Protects HUVECs against Hydrogen Peroxide Induced Mitochondrial Dysfunction and Oxidative Stress  

PubMed Central

Background Hydrogen sulfide (H2S) has been shown to have cytoprotective effects in models of hypertension, ischemia/reperfusion and Alzheimer's disease. However, little is known about its effects or mechanisms of action in atherosclerosis. Therefore, in the current study we evaluated the pharmacological effects of H2S on antioxidant defenses and mitochondria protection against hydrogen peroxide (H2O2) induced endothelial cells damage. Methodology and Principal Findings H2S, at non-cytotoxic levels, exerts a concentration dependent protective effect in human umbilical vein endothelial cells (HUVECs) exposed to H2O2. Analysis of ATP synthesis, mitochondrial membrane potential (??m) and cytochrome c release from mitochondria indicated that mitochondrial function was preserved by pretreatment with H2S. In contrast, in H2O2 exposed endothelial cells mitochondria appeared swollen or ruptured. In additional experiments, H2S was also found to preserve the activities and protein expressions levels of the antioxidants enzymes, superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase in H2O2 exposed cells. ROS and lipid peroxidation, as assessed by measuring H2DCFDA, dihydroethidium (DHE), diphenyl-l-pyrenylphosphine (DPPP) and malonaldehyde (MDA) levels, were also inhibited by H2S treatment. Interestingly, in the current model, D, L-propargylglycine (PAG), a selective inhibitor of cystathionine ?-lyase (CSE), abolished the protective effects of H2S donors. Innovation This study is the first to show that H2S can inhibit H2O2 mediated mitochondrial dysfunction in human endothelial cells by preserving antioxidant defences. Significance H2S may protect against atherosclerosis by preventing H2O2 induced injury to endothelial cells. These effects appear to be mediated via the preservation of mitochondrial function and by reducing the deleterious effects of oxidative stress. PMID:23393548

Wen, Ya-Dan; Wang, Hong; Kho, Sok-Hong; Rinkiko, Suguro; Sheng, Xiong; Shen, Han-Ming; Zhu, Yi-Zhun

2013-01-01

207

A Comparative Study of Spectrophotometric and Iodometric Back Titration Methods for Hydrogen Sulfide Determination in Anoxic Basins  

Microsoft Academic Search

Iodometric Back Titration (IBT) and Spectrophotometric (SPM) methods are two common methods used in the determination of hydrogen sulfide concentrations in anoxic basins, like in the upper sections of the Black Sea anoxic waters. Although the results obtained by both methods are in agreement when the concentrations of sulfide are higher than 30 ?M\\/1, IBT analysis gives more reproducible results

Özden Batürk; Alexander Romanov; Serap Gokmen; Sergey Konovalov

2000-01-01

208

Direct Chlorination Process for geothermal power plant off-gas - hydrogen sulfide abatement  

SciTech Connect

The Direct Chlorination Process removes hydrogen sulfide from geothermal off-gases by reacting hydrogen sulfide with chlorine in the gas phase. Hydrogen chloride and elemental sulfur are formed by this reaction. The Direct Chlorination Process has been successfully demonstrated by an on-site operation of a pilot plant at the 3 M We HPG-A geothermal power plant in the Puna District on the island of Hawaii. Over 99.5% hydrogen sulfide removal was achieved in a single reaction stage. Chlorine gas did not escape the pilot plant, even when 90% excess chlorine gas was used. A preliminary economic evaluation of the Direct Chlorination Process indicates that it is very competitive with the Stretford Process Compared to the Stretford Process, the Direct Chlorination process requires about one-third the initial capital investment and about one-fourth the net daily expenditure. Because of the higher cost of chemicals and the restricted markets in Hawaii, the economic viability of this process in Hawaii is questionable.

Sims, A.V.

1983-06-01

209

Elevated corrosion rates and hydrogen sulfide in homes with 'Chinese Drywall'.  

PubMed

In December 2008, the U.S. Consumer Product Safety Commission (CPSC) began receiving reports about odors, corrosion, and health concerns related to drywall originating from China. In response, a detailed environmental health and engineering evaluation was conducted of 41 complaint and 10 non-complaint homes in the Southeast U.S. Each home investigation included characterization of: 1) drywall composition; 2) indoor and outdoor air quality; 3) temperature, moisture, and building ventilation; and 4) copper and silver corrosion rates. Complaint homes had significantly higher hydrogen sulfide concentrations (mean 0.82 vs. sulfide and silver sulfide corrosion compared to non-complaint homes (Cu(2)S: 476 vs. <32 Å/30 d, p<0.01; Ag(2)S: 1472 vs. 389 Å/30 d, p<0.01). The abundance of carbonate and strontium in drywall was also elevated in complaint homes, and appears to be useful objective marker of problematic drywall in homes that meet other screening criteria (e.g., constructed or renovated in 2006-2007, reports of malodor and accelerated corrosion). This research provides empirical evidence of the direct association between homes constructed with 'Chinese Drywall' in 2006-2007 and elevated corrosion rates and hydrogen sulfide concentrations in indoor air. PMID:22525559

Allen, Joseph G; MacIntosh, David L; Saltzman, Lori E; Baker, Brian J; Matheson, Joanna M; Recht, Joel R; Minegishi, Taeko; Fragala, Matt A; Myatt, Theodore A; Spengler, John D; Stewart, James H; McCarthy, John F

2012-06-01

210

Pad B Liquid Hydrogen Storage Tank  

NASA Technical Reports Server (NTRS)

Kennedy Space Center is home to two liquid hydrogen storage tanks, one at each launch pad of Launch Complex 39. The liquid hydrogen storage tank at Launch Pad B has a significantly higher boil off rate that the liquid hydrogen storage tank at Launch Pad A. This research looks at various calculations concerning the at Launch Pad B in an attempt to develop a solution to the excess boil off rate. We will look at Perlite levels inside the tank, Boil off rates, conductive heat transfer, and radiant heat transfer through the tank. As a conclusion to the research, we will model the effects of placing an external insulation to the tank in order to reduce the boil off rate and increase the economic efficiency of the liquid hydrogen storage tanks.

Hall, Felicia

2007-01-01

211

75 FR 19319 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting; Extension of Comment...  

Federal Register 2010, 2011, 2012, 2013

...Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting; Extension...Right-to- Know Act (EPCRA) section 313 toxic chemical release reporting requirements...Reporting and recordkeeping requirements, and Toxic chemicals. Dated: April 7, 2010....

2010-04-14

212

Requirements to Crack Resistance of Materials of Oil and Gas Equipment Operating in Hydrogen-Sulfide Media  

Microsoft Academic Search

We investigate the crack resistance of low-alloy pipe steels, their welds, and nickel and titanium alloys in air and in a hydrogen-sulfide solution NACE. We determine the stress intensity factors in the course of testing in air Kc and in hydrogen sulfide KIssc as well as the coefficients of medium influence BIssc = KIssc\\/Kc. We establish minimum admissible values KIsscmin

O. I. Radkevych

2001-01-01

213

Hydrogen sulfide protects colon cancer cells from chemopreventative agent ? ? ? ? ?-phenylethyl isothiocyanate induced apoptosis  

Microsoft Academic Search

Abstract Abstract Abstract Abstract AIM: Hydrogen sulfide (H2S) is a prominent gaseous constituent of the gastrointestinal (GI) tract with known cytotoxic properties. Endogenous concentrations of H2S are reported to range between 0.2-3.4 mmol\\/L in the GI tract of mice and humans. Considering such high levels we speculate that, at non-toxic concentrations, H2S may interact with chemical agents and alter the

Peter Rose; Philip K Moore; Shen Han Ming; Ong Choon Nam; Jeffrey S Armstrong; Matt Whiteman

2005-01-01

214

Selective oxidation of hydrogen sulfide to ammonium thiosulfate and sulfur over vanadium-bismuth oxide catalysts  

Microsoft Academic Search

The selective oxidation of hydrogen sulfide containing excess water and ammonia was studied over vanadium-bismuth mixed oxide catalysts. The investigation was focused on understanding the complex reaction steps and the roles of each metal oxide. Therefore, supported V2O5\\/TiO2, V-Bi-O\\/TiO2 catalysts and a mechanical mixture of V2O5 + Bi2O3 were tested in the reaction. Ammonia reacted either with H2S or SO2,

Young-Gu Cho; Dae-Kwang Park; Dae-Won Park; Hee-Chul Woo; Jong-Shik Chung

2002-01-01

215

Effectiveness and Mechanisms of Hydrogen Sulfide Adsorption by Camphor-derived Biochar  

Microsoft Academic Search

The characteristics and mechanisms of hydrogen sulfide (H2S) adsorption on a biochar through pyrolysis at various temperatures (100 °C to 500 °C) were investigated. The biochar used in the current study was derived from the camphor tree (Cinnamomum camphora). The samples were ground and sieved to produce particle sizes of 0.4 mm to 1.25 mm, 0.3 mm to 0.4 mm,

Guofeng Shang; Guoqing Shen; Tingting Wang; Qin Chen

2012-01-01

216

Influence of Gas Composition on Hydrogen Sulfide Removal at Moderate Temperature  

Microsoft Academic Search

The influence of gas composition on hydrogen sulfide removal from coal gas by zinc oxide sorbent was investigated at moderate temperature using TG technique. It was found that the removal of H2S by ZnO can vary greatly depending on the gas composition. Addition of H2, H2O to the inlet gas stream could promote the reaction rate, whereas the desulfurization was

Hui-Ling Fan; Ju Shangguan; Li-Tong Liang; Fang Shen

2011-01-01

217

Fiber optic sensors using novel substrates for hydrogen sulfide determination by solid surface fluorescence  

Microsoft Academic Search

Two different fiber optic sensors were developed for the determination of hydrogen sulfide at ppb concentration levels; a probe-type fiber optic sensor coated with polyethylene oxide containing 0.5 M CdCl2 and a fiber optic sensor utilizing 0.5 M CdCl2-pretreated filter paper as solid substrate. In the first type, CdCl2–polyethyleneoxide (PEO) mixture was coated onto the tip of a fiber optic

Ahmet E Ero?lu; Mürvet Volkan; O. Yavuz Ataman

2000-01-01

218

Removal of hydrogen sulfide by clinoptilolite in a fixed bed adsorber  

Microsoft Academic Search

Due to its toxic and corrosive nature, H2S should be safely removed from the gases produced in gasification or combustion processes. In this study, adsorption of hydrogen sulfide was investigated on a natural zeolite, namely clinoptilolite. H2S adsorption characteristics of Western Anatolian clinoptilolite was studied in a fixed-bed system at different temperatures between 100 and 600°C at atmospheric pressure. H2S

Sena Ya?yerli; ?rfan Ar; Gül?en Do?u; Timur Do?u

2002-01-01

219

Removal of hydrogen sulfide by clinoptilolite in a fixed bed adsorber  

Microsoft Academic Search

Due to its toxic and corrosive nature, H2S should be safely removed from the gases produced in gasification or combustion processes. In this study, adsorption of hydrogen sulfide was investigated on a natural zeolite, namely clinoptilolite. H2S adsorption characteristics of Western Anatolian clinoptilolite was studied in a fixed-bed system at different temperatures between 100 and 600 8C at atmospheric pressure.

Sena Yasyerli; Irfan Ar; Timur Dog

220

Computational prediction of hydrogen sulfide and methane separation at room temperature by anatase titanium dioxide  

NASA Astrophysics Data System (ADS)

Removal of hydrogen sulfide (H2S) is a key step for biogas purification. Herein, the adsorption of H2S and methane (CH4) on anatase titanium dioxide (TiO2) has been studied by first principle calculations. It is found that TiO2 offers excellent capacity for the H2S/CH4 separation. Using force-field molecular dynamics, this high separation capacity has been examined at room temperature.

Sun, Chenghua

2013-02-01

221

Ammonia, hydrogen sulfide, carbon dioxide and particulate matter emissions from California high-rise layer houses  

NASA Astrophysics Data System (ADS)

Ammonia and hydrogen sulfide are hazardous substances that are regulated by the U.S. Environmental Protection Agency through community right-to-know legislation (EPCRA, EPA, 2011). The emissions of ammonia and hydrogen sulfide from large commercial layer facilities are of concern to legislators and nearby neighbors. Particulate matter (PM 10 and PM 2.5) released from layer houses are two of seven criteria pollutants for which EPA has set National Ambient Air Quality Standards as required by the Clean Air Act. Therefore, it is important to quantify the baseline emissions of these pollutants. The emissions of ammonia, hydrogen sulfide, carbon dioxide and PM from two California high-rise layer houses were monitored for two years from October 2007 to October 2009. Each house had 32,500 caged laying hens. The monitoring site was setup in compliance with a U.S. EPA-approved quality assurance project plan. The results showed the average daily mean emission rates of ammonia, hydrogen sulfide and carbon dioxide were 0.95 ± 0.67 (standard deviation) g d -1 bird -1, 1.27 ± 0.78 mg d -1 bird -1 and 91.4 ± 16.5 g d -1 bird -1, respectively. The average daily mean emission rates of PM 2.5, PM 10 and total suspended particulate (TSP) were 5.9 ± 12.6, 33.4 ± 27.4, and 78.0 ± 42.7 mg d -1 bird -1, respectively. It was observed that ammonia emission rates in summer were lower than in winter because the high airflow stabilized the manure by drying it. The reductions due to lower moisture content were greater than the increases due to higher temperature. However, PM 10 emission rates in summer were higher than in winter because the drier conditions coupled with higher internal air velocities increased PM 10 release from feathers, feed and manure.

Lin, X.-J.; Cortus, E. L.; Zhang, R.; Jiang, S.; Heber, A. J.

2012-01-01

222

Hydrogen sulfide antagonizes homocysteine-induced neurotoxicity in PC12 cells  

Microsoft Academic Search

Hydrogen sulfide (H2S) has been shown to protect neurons against oxidative stress. Lower levels of H2S as well as accumulation of homocysteine (Hcy), a strong risk of Alzheimer's disease (AD), are reported in the brains of AD patients. The aim of present study is to explore the protection of H2S against Hcy-induced cytotoxicity and apoptosis and the molecular mechanisms underlying

Xiao-Qing Tang; Xin-Tian Shen; Yi-E Huang; Yan-Kai Ren; Rong-Qian Chen; Bi Hu; Jian-Qin He; Wei-Lan Yin; Jin-Hua Xu; Zhi-Sheng Jiang

2010-01-01

223

Inhibition of Hydrogen Sulfide Generation Contributes to 1-Methy-4-Phenylpyridinium IonInduced Neurotoxicity  

Microsoft Academic Search

Reactive oxygen species (ROS) overproduction contributes to the neurotoxicity of 1-methy-4-phenylpyridinium ion (MPP+). Increasing studies have shown that hydrogen sulfide (H2S) is an endogenous antioxidant gas. We have hypothesized that MPP+-caused neurotoxicity may involve the imbalance of proportion to this endogenous protective antioxidant gas. The aim of this\\u000a study is to evaluate whether MPP+ disturbs H2S synthesis in PC12 cells,

Xiao-Qing Tang; Li-Li Fan; Yu-Juan Li; Xin-Tian Shen; Yuan-Yuan Zhuan; Jian-Qin He; Jin-Hua Xu; Bi Hu; Yuan-Jian Li

2011-01-01

224

Hydrogen sulfide protects soybean seedlings against drought-induced oxidative stress  

Microsoft Academic Search

Increasing evidence indicates that hydrogen sulfide (H2S) is the third “gas signal molecule” after NO and CO in animal. In the present study, we found that soybean (Glycine max L.) seedlings sprayed with exogenous H2S donor NaHS prolonged the longer survival time of life, and enlarged higher biomass of both leaf and root than in non-sprayed\\u000a controls under continuous drought

Hua Zhang; Hao Jiao; Cheng-Xi Jiang; Song-Hua Wang; Zhao-Jun Wei; Jian-Ping Luo; Russell L. Jones

2010-01-01

225

A novel hydrogen sulfide donor causes stomatal opening and reduces nitric oxide accumulation  

Microsoft Academic Search

Effects of hydrogen sulfide (H2S) on plant physiology have been previously studied, but such studies have relied on the use of NaSH as a method for supplying H2S to tissues. Now new compounds which give a less severe H2S shock and a more prolonged exposure to H2S have been developed. Here the effects of one such compound, GYY4137, has been

M. Lisjak; N. Srivastava; T. Teklic; L. Civale; K. Lewandowski; I. Wilson; M. E. Wood; M. Whiteman; J. T. Hancock

2010-01-01

226

Inhibition of Hydrogen Sulfide Generation Contributes to Gastric Injury Caused by Anti-Inflammatory Nonsteroidal Drugs  

Microsoft Academic Search

Background & Aims: Hydrogen sulfide (H2S), an endog- enous gaseous mediator that causes vasodilation, is generated in mammalian tissues by cystathionine -synthase (CBS) and cystathionine--lyase (CSE). Here, we have investigated the role of H2S in a rodent model of nonsteroidal anti-inflammatory drug (NSAID) gastropathy. Methods: Rats were given acetyl salycilic acid (ASA) or an NSAID alone or in combination with

STEFANO FIORUCCI; ELISABETTA ANTONELLI; ELEONORA DISTRUTTI; GIOVANNI RIZZO; ANDREA MENCARELLI; STEFANO ORLANDI; RENATA ZANARDO; BARBARA RENGA; MOSES DI SANTE; ANTONIO MORELLI; GIUSEPPE CIRINO; JOHN L. WALLACE

2005-01-01

227

Evidence That Hydrogen Sulfide Exerts Antinociceptive Effects in the Gastrointestinal Tract by Activating KATP Channels  

Microsoft Academic Search

Hydrogen sulfide (H2S) functions as a neuromodulator, but whether it modulates visceral perception and pain is unknown. Cystathionine -synthase (CBS) and cystathionine--lyase (CSE) mediate enzymatic generation of H2S in mammalian cells. Here we have investigated the role of H2S in modulating nociception to colorectal distension, a model that mimics some features of the irritable bowel syndrome. Four graded (0.4-1.6 ml

Eleonora Distrutti; Luca Sediari; Andrea Mencarelli; Barbara Renga; Stefano Orlandi; Elisabetta Antonelli; Fiorenza Roviezzo; Antonio Morelli; Giuseppe Cirino; John L. Wallace; Stefano Fiorucci

2005-01-01

228

Regulation of heart function by endogenous gaseous mediators-crosstalk between nitric oxide and hydrogen sulfide.  

PubMed

Both nitric oxide (NO) and hydrogen sulfide (H(2)S) are two important gaseous mediators regulating heart function. The present study examined the interaction between these two biological gases and its role in the heart. We found that l-arginine, a substrate of NO synthase, decreased the amplitudes of myocyte contraction and electrically induced calcium transients. Sodium hydrogen sulfide (an H(2)S donor), which alone had minor effect, reversed the negative inotropic effects of l-arginine. The effect of l-arginine + sodium hydrogen sulfide was abolished by three thiols (l-cysteine, N-acetyl-cysteine, and glutathione), suggesting that the effect of H(2)S + NO is thiol sensitive. The stimulatory effect on heart contractility was also induced by GYY4137, a slow-releasing H(2)S donor, when used together with sodium nitroprusside, an NO-releasing donor. More importantly, enzymatic generation of H(2)S from recombinant cystathionine-?-lyase protein also interacted with endogenous NO generated from l-arginine to stimulate heart contraction. In summary, our data suggest that endogenous NO may interact with H(2)S to produce a new biological mediator that produces positive inotropic effect. The crosstalk between H(2)S and NO also suggests an intriguing potential for the endogenous formation of a thiol-sensitive molecule, which may be of physiological significance in the heart. PMID:21194352

Yong, Qian-Chen; Cheong, Jia Ling; Hua, Fei; Deng, Lih-Wen; Khoo, Yok Moi; Lee, How-Sung; Perry, Alexis; Wood, Mark; Whiteman, Matthew; Bian, Jin-Song

2011-06-01

229

Study of the interaction between water and hydrogen sulfide with polycyclic aromatic hydrocarbons  

NASA Astrophysics Data System (ADS)

A computational study has been carried out for determining the characteristics of the interaction between one water and hydrogen sulfide molecule with a series of polycyclic aromatic hydrocarbons of increasing size, namely, benzene, anthracene, triphenylene, coronene, circumcoronene, and dicircumcoronene. Potential energy curves were calculated for structures where H2X (X=O,S) molecule is located over the central six-membered ring with its hydrogen atoms pointing toward to (mode A) or away from (mode B) the hydrocarbon. The accuracy of different methods has been tested against the results of coupled cluster calculations extrapolated to basis set limit for the smaller hydrocarbons. The spin component scaled MP2 (SCS-MP2) method and a density functional theory method empirically corrected for dispersion (DFT-D) reproduce fairly well the results of high level calculations and therefore were employed for studying the larger systems, though DFT-D seems to underestimate the interaction in hydrogen sulfide clusters. Water complexes in mode A have interaction energies that hardly change with the size of the hydrocarbon due to compensation between the increase in the correlation contribution to the interaction energy and the increase in the repulsive character of the Hartree-Fock energy. For all the other clusters studied, there is a continuous increase in the intensity of the interaction as the size of the hydrocarbon increases, suggesting already converged values for circumcoronene. The interaction energy for water clusters extrapolated to an infinite number of carbon atoms amounts to -13.0 and -15.8 kJ/mol with SCS-MP2 and DFT-D, respectively. Hydrogen sulfide interacts more strongly than water with the hydrocarbons studied, leading to a limiting value of -21.7 kJ/mol with the SCS-MP2 method. Also, complexes in mode B are less stable than the corresponding A structures, with interaction energies amounting to -8.2 and -18.2 kJ/mol for water and hydrogen sulfide, respectively. The DFT-D calculations give values of -16.2 and -9.3 kJ/mol for hydrogen sulfide complexes in modes A and B, less negative than those predicted by the SCS-MP2 method, probably indicating problems with sulfur dispersion parameters.

Cabaleiro-Lago, Enrique M.; Carrazana-García, Jorge A.; Rodríguez-Otero, Jesús

2009-06-01

230

Multicomponent sulfides as narrow gap hydrogen evolution photocatalysts.  

PubMed

A series of mixed crystals composed of Cu(2)ZnSnS(4), Ag(2)ZnSnS(4) and ZnS was prepared by co-precipitation of the corresponding metal ions in aqueous sodium sulfide followed by annealing in a sulfur atmosphere. Ideal solid solutions of Cu(2)ZnSnS(4) and Ag(2)ZnSnS(4) with a kesterite structure ((Cu(x)Ag(1-x))(2)ZnSnS(4) (0 ?x? 1)) were successfully obtained by this procedure, as confirmed by their X-ray diffraction (XRD) patterns and energy-diffuse X-ray (EDX) analyses. On the other hand, the solubility of ZnS in these kesterite compounds was found to be limited: the upper limit of the ratio of ZnS to (Cu(x)Ag(1-x))(2)ZnSnS(4) was less than 0.1, regardless of the Cu-Ag ratio in (Cu(x)Ag(1-x))(2)ZnSnS(4). Based on the results for dependence of their photoabsorption properties on atomic compositions, a plausible band structure is discussed. Evaluation of the photocatalytic activity for H(2) evolution of these mixed crystals from an aqueous solution containing S(2-) and SO(3)(2-) ions upon loading Ru catalysts under simulated solar radiation (AM 1.5) revealed that active compounds for this reaction should contain both dissolved ZnS and Ag components. The dissolved ZnS in (Cu(x)Ag(1-x))(2)ZnSnS(4) gave upward shifts of their conduction band edges. Moreover, the presence of Ag in the solid solution provided n-type conductivity, leading to efficient migration of photogenerated electrons to the surface to induce water reduction into H(2). PMID:20852813

Ikeda, Shigeru; Nakamura, Takayuki; Harada, Takashi; Matsumura, Michio

2010-11-14

231

DETAIL OF THE LIQUID HYDROGEN AND LIQUID OXYGEN VENT VALVES, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL OF THE LIQUID HYDROGEN AND LIQUID OXYGEN VENT VALVES, SIXTH LEVEL OF THE EXTERNAL TANK CHECK-OUT CELLS, HB-2, FACING NORTHEAST - Cape Canaveral Air Force Station, Launch Complex 39, Vehicle Assembly Building, VAB Road, East of Kennedy Parkway North, Cape Canaveral, Brevard County, FL

232

Giant hydrogen sulfide plume in the oxygen minimum zone off Peru supports chemolithoautotrophy.  

PubMed

In Eastern Boundary Upwelling Systems nutrient-rich waters are transported to the ocean surface, fuelling high photoautotrophic primary production. Subsequent heterotrophic decomposition of the produced biomass increases the oxygen-depletion at intermediate water depths, which can result in the formation of oxygen minimum zones (OMZ). OMZs can sporadically accumulate hydrogen sulfide (H2S), which is toxic to most multicellular organisms and has been implicated in massive fish kills. During a cruise to the OMZ off Peru in January 2009 we found a sulfidic plume in continental shelf waters, covering an area >5500 km(2), which contained ?2.2×10(4) tons of H2S. This was the first time that H2S was measured in the Peruvian OMZ and with ?440 km(3) the largest plume ever reported for oceanic waters. We assessed the phylogenetic and functional diversity of the inhabiting microbial community by high-throughput sequencing of DNA and RNA, while its metabolic activity was determined with rate measurements of carbon fixation and nitrogen transformation processes. The waters were dominated by several distinct ?-, ?- and ?-proteobacterial taxa associated with either sulfur oxidation or sulfate reduction. Our results suggest that these chemolithoautotrophic bacteria utilized several oxidants (oxygen, nitrate, nitrite, nitric oxide and nitrous oxide) to detoxify the sulfidic waters well below the oxic surface. The chemolithoautotrophic activity at our sampling site led to high rates of dark carbon fixation. Assuming that these chemolithoautotrophic rates were maintained throughout the sulfidic waters, they could be representing as much as ?30% of the photoautotrophic carbon fixation. Postulated changes such as eutrophication and global warming, which lead to an expansion and intensification of OMZs, might also increase the frequency of sulfidic waters. We suggest that the chemolithoautotrophically fixed carbon may be involved in a negative feedback loop that could fuel further sulfate reduction and potentially stabilize the sulfidic OMZ waters. PMID:23990875

Schunck, Harald; Lavik, Gaute; Desai, Dhwani K; Großkopf, Tobias; Kalvelage, Tim; Löscher, Carolin R; Paulmier, Aurélien; Contreras, Sergio; Siegel, Herbert; Holtappels, Moritz; Rosenstiel, Philip; Schilhabel, Markus B; Graco, Michelle; Schmitz, Ruth A; Kuypers, Marcel M M; Laroche, Julie

2013-01-01

233

Giant Hydrogen Sulfide Plume in the Oxygen Minimum Zone off Peru Supports Chemolithoautotrophy  

PubMed Central

In Eastern Boundary Upwelling Systems nutrient-rich waters are transported to the ocean surface, fuelling high photoautotrophic primary production. Subsequent heterotrophic decomposition of the produced biomass increases the oxygen-depletion at intermediate water depths, which can result in the formation of oxygen minimum zones (OMZ). OMZs can sporadically accumulate hydrogen sulfide (H2S), which is toxic to most multicellular organisms and has been implicated in massive fish kills. During a cruise to the OMZ off Peru in January 2009 we found a sulfidic plume in continental shelf waters, covering an area >5500 km2, which contained ?2.2×104 tons of H2S. This was the first time that H2S was measured in the Peruvian OMZ and with ?440 km3 the largest plume ever reported for oceanic waters. We assessed the phylogenetic and functional diversity of the inhabiting microbial community by high-throughput sequencing of DNA and RNA, while its metabolic activity was determined with rate measurements of carbon fixation and nitrogen transformation processes. The waters were dominated by several distinct ?-, ?- and ?-proteobacterial taxa associated with either sulfur oxidation or sulfate reduction. Our results suggest that these chemolithoautotrophic bacteria utilized several oxidants (oxygen, nitrate, nitrite, nitric oxide and nitrous oxide) to detoxify the sulfidic waters well below the oxic surface. The chemolithoautotrophic activity at our sampling site led to high rates of dark carbon fixation. Assuming that these chemolithoautotrophic rates were maintained throughout the sulfidic waters, they could be representing as much as ?30% of the photoautotrophic carbon fixation. Postulated changes such as eutrophication and global warming, which lead to an expansion and intensification of OMZs, might also increase the frequency of sulfidic waters. We suggest that the chemolithoautotrophically fixed carbon may be involved in a negative feedback loop that could fuel further sulfate reduction and potentially stabilize the sulfidic OMZ waters. PMID:23990875

Grosskopf, Tobias; Kalvelage, Tim; Loscher, Carolin R.; Paulmier, Aurelien; Contreras, Sergio; Siegel, Herbert; Holtappels, Moritz; Rosenstiel, Philip; Schilhabel, Markus B.; Graco, Michelle; Schmitz, Ruth A.; Kuypers, Marcel M. M.; LaRoche, Julie

2013-01-01

234

Low-power, fast, selective nanoparticle-based hydrogen sulfide gas sensor  

NASA Astrophysics Data System (ADS)

We demonstrate a small, low-cost, low-power, highly sensitive, and selective nanomaterials-based gas sensor. A network of tungsten oxide nanoparticles is heated by an on-chip microhotplate while the conductance of the network is monitored. The device can be heated with short pulses, thereby drastically lowering the power consumption, without diminishing the sensor response. The sensor shows high sensitivity to hydrogen sulfide and does not have significant cross sensitivities to hydrogen, water, or methane, gases likely to be present in operation. A sensing mechanism is proposed, and its effect on electronic properties is discussed.

Mickelson, William; Sussman, Allen; Zettl, Alex

2012-04-01

235

Low-power, fast, selective nanoparticle-based hydrogen sulfide gas sensor  

NASA Astrophysics Data System (ADS)

We demonstrate a small, low-cost, low-power, highly sensitive, and selective nanomaterials-based gas sensor. A network of tungsten oxide nanoparticles is heated by an on-chip microhotplate while the conductance of the network is monitored. The device can be heated with short pulses, thereby drastically lowering the power consumption, without diminishing the sensor response. The sensor shows high sensitivity to hydrogen sulfide and does not have significant cross sensitivities to hydrogen, water, or methane, gases likely to be present in operation. A sensing mechanism is proposed, and its effect on electronic properties is discussed.

Sussman, Allen; Mickelson, William; Zettl, A.

2013-03-01

236

Plasma-chemical treatment of hydrogen sulfide in natural gas processing. Final report, May 1991--December 1992  

SciTech Connect

A new process for the treatment of hydrogen sulfide waste that uses microwave plasma-chemical technology has been under development in Russia and the United States. Whereas the present waste-treatment technology, at best, only recovers sulfur, this novel process recovers both hydrogen and sulfur by dissociating hydrogen sulfide in a plasma by means of a microwave or radio-frequency reactor. A research project has been undertaken to determine the suitability of the plasma process in natural gas processing applications. The experiments tested acid-gas compositions with 30--65% carbon dioxide, 0--7% water, and 0--0.2% of a standard mixture of pipeline gas. The balance gas in all cases was hydrogen sulfide. The reactor pressure for the experiments was 50 torr, and the microwave power was 1.0 kW. Conversions of hydrogen sulfide ranged from 80 to 100%, while 35--50% of the carbon dioxide was converted to carbon monoxide. This conversion of carbon dioxide resulted in a loss of hydrogen production and an energy loss from a hydrogen sulfide waste-treatment perspective. Tests of a direct natural gas treatment concept showed that hydrocarbon losses were unacceptably high; consequently, the concept would not be economically viable.

Harkness, J.B.L.; Doctor, R.D. [Argonne National Lab., IL (United States)

1993-05-01

237

Electrochemical separation and concentration of hydrogen sulfide from gas mixtures  

DOEpatents

A method of removing sulfur oxides of H.sub.2 S from high temperature gas mixtures (150.degree.-1000.degree. C.) is the subject of the present invention. An electrochemical cell is employed. The cell is provided with inert electrodes and an electrolyte which will provide anions compatible with the sulfur containing anions formed at the anode. The electrolyte is also selected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the sulfur gases are converted to SO.sub.4 -- or, in the case of H.sub.2 S, to S--. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels (>10X). Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

Winnick, Jack (Atlanta, GA); Sather, Norman F. (Naperville, IL); Huang, Hann S. (Darian, IL)

1984-10-30

238

Hydrogen sulfide (H2S) releasing agents: chemistry and biological applications.  

PubMed

Hydrogen sulfide (H2S) is a newly recognized signaling molecule with very potent cytoprotective actions. The fields of H2S physiology and pharmacology have been rapidly growing in recent years, but a number of fundamental issues must be addressed to advance our understanding of the biology and clinical potential of H2S in the future. Hydrogen sulfide releasing agents (also known as H2S donors) have been widely used in these fields. These compounds are not only useful research tools, but also potential therapeutic agents. It is therefore important to study the chemistry and pharmacology of exogenous H2S and to be aware of the limitations associated with the choice of donors used to generate H2S in vitro and in vivo. In this review we summarized the developments and limitations of currently available donors including H2S gas, sulfide salts, garlic-derived sulfur compounds, Lawesson's reagent/analogs, 1,2-dithiole-3-thiones, thiol-activated donors, photo-caged donors, and thioamino acids. Some biological applications of these donors were also discussed. PMID:25019301

Zhao, Yu; Biggs, Tyler D; Xian, Ming

2014-10-14

239

Experimental partitioning of uranium between liquid iron sulfide and liquid silicate: Implications for radioactivity in the Earth’s core  

NASA Astrophysics Data System (ADS)

Measurable uranium (U) is found in metal sulfide liquids in equilibrium with molten silicate at conditions appropriate for a planetary magma ocean: 1-10 GPa, 1750-2100 °C, 0-28 wt% S, and fO 2 2 log units below IW. However, the transfer of U from metal sulfide to silicate under our experimental conditions is so complete that insufficient U would remain so as to be of any importance to the core's heat budget. U content in the sulfide phase increases strongly with S content but shows no significant variability with either pressure or temperature. Maximum DUsulfide/silicate is 0.001 while most values are considerably lower.

Wheeler, Kevin T.; Walker, David; Fei, Yingwei; Minarik, William G.; McDonough, William F.

2006-03-01

240

Modeling leaks from liquid hydrogen storage systems.  

SciTech Connect

This report documents a series of models for describing intended and unintended discharges from liquid hydrogen storage systems. Typically these systems store hydrogen in the saturated state at approximately five to ten atmospheres. Some of models discussed here are equilibrium-based models that make use of the NIST thermodynamic models to specify the states of multiphase hydrogen and air-hydrogen mixtures. Two types of discharges are considered: slow leaks where hydrogen enters the ambient at atmospheric pressure and fast leaks where the hydrogen flow is usually choked and expands into the ambient through an underexpanded jet. In order to avoid the complexities of supersonic flow, a single Mach disk model is proposed for fast leaks that are choked. The velocity and state of hydrogen downstream of the Mach disk leads to a more tractable subsonic boundary condition. However, the hydrogen temperature exiting all leaks (fast or slow, from saturated liquid or saturated vapor) is approximately 20.4 K. At these temperatures, any entrained air would likely condense or even freeze leading to an air-hydrogen mixture that cannot be characterized by the REFPROP subroutines. For this reason a plug flow entrainment model is proposed to treat a short zone of initial entrainment and heating. The model predicts the quantity of entrained air required to bring the air-hydrogen mixture to a temperature of approximately 65 K at one atmosphere. At this temperature the mixture can be treated as a mixture of ideal gases and is much more amenable to modeling with Gaussian entrainment models and CFD codes. A Gaussian entrainment model is formulated to predict the trajectory and properties of a cold hydrogen jet leaking into ambient air. The model shows that similarity between two jets depends on the densimetric Froude number, density ratio and initial hydrogen concentration.

Winters, William Stanley, Jr.

2009-01-01

241

Designing reaction-based fluorescent probes for selective hydrogen sulfide detection.  

PubMed

Hydrogen sulfide (H2S) is a biologically generated, gaseous signaling molecule that mediates a wide range of physiological functions and is misregulated in numerous pathologies ranging from neurodegenerative disease to hypertension to diabetes. Despite swelling interest, a deeper understanding of the biological roles played by H2S has been hindered by a lack of tools for the real-time visualization of its production in living organisms. Recently, reaction-based fluorescent probes have emerged as an ideal approach for selective H2S imaging and are attracting increasing attention with many new innovative designs being introduced. This review will highlight some of the most fruitful reaction-based strategies, including reduction-based, nucleophilic-based, and metal sulfide precipitation-based fluorescent sensors. Strategies to address the key design challenges of sensitivity, selectivity, in vivo compatibility, and quantification will be discussed using examples of recently developed molecular scaffolds for selective H2S detection. PMID:24239492

Lippert, Alexander R

2014-04-01

242

Simulation of spray drying with reaction: Absorption of hydrogen sulfide in ammoniacal solution of zinc chloride  

SciTech Connect

Absorption of hydrogen sulfide gas in ammoniacal solution of zinc chloride is accompanied with an instantaneous chemical reaction forming zinc sulfide precipitates. Such reactions are most suited for operation of spray drying with reaction. A mathematical model for the system which incorporates chemical reaction, heat, mass and momentum transfer has been proposed. It is assumed that the gases and the spray is considered monodisperse for sake of simplicity. The differential equations derived for the model have been solved as an initial value problem using the Runge-Kutta method. The variations of temperature, humidity, droplet diameter, moisture content and concentrations of reactants are predicted along the length of the column and compared with experimental data.

Chander, H.; Ghosh, P.K. (National Physical Lab., New Delhi (India)); Baveja, K.K.; Dhingra, S.C. (Indian Inst. of Tech., New Delhi (India))

1993-01-01

243

Redox biology of hydrogen sulfide: Implications for physiology, pathophysiology, and pharmacology?  

PubMed Central

Hydrogen sulfide (H2S) has emerged as a critical mediator of multiple physiological processes in mammalian systems. The pathways involved in the production, consumption, and mechanism of action of H2S appear to be sensitive to alterations in the cellular redox state and O2 tension. Indeed, the catabolism of H2S through a putative oxidation pathway, the sulfide quinone oxido-reductase system, is highly dependent on O2 tension. Dysregulation of H2S homeostasis has also been implicated in numerous pathological conditions and diseases. In this review, the chemistry and the main physiological actions of H2S are presented. Some examples highlighting the cytoprotective actions of H2S within the context of cardiovascular disease are also reported. Elucidation of the redox biology of H2S will enable the development of new pharmacological agents based on this intriguing new redox cellular signal. PMID:23795345

Stein, Asaf; Bailey, Shannon M.

2013-01-01

244

Hypoxia-induced arterial chemoreceptor stimulation and hydrogen sulfide: too much or too little?  

PubMed

This brief review presents and discusses some of the important issues surrounding the theory which asserts that endogenous hydrogen sulfide (H(2)S) is the mediator of, or at least an important contributor to, hypoxia-induced arterial chemorereceptor stimulation. The view presented here is that before H(2)S can seriously be considered as a candidate for transducing the O(2)-signal in the carotid bodies (CB), fundamental contradictions need to be resolved. One of these major contradictions is certainly the discrepancy between the levels of H(2)S endogenously present in the CB during hypoxia compared to the levels required to stimulate the arterial chemoreceptors in vitro. Very small amounts of H(2)S are thought to be produced endogenously during a given level of hypoxia, yet the partial pressure of tissue H(2)S which is needed to produce an effect commensurate with that of hypoxia is thousands to millions of times higher. This review discusses this and other contradictions in light of what is known about H(2)S concentration and production in various tissues, the lessons we have learnt from the response to exogenous sulfide and the ability of the blood and the mitochondria to oxidize very large amounts of sulfide. These considerations suggest that the increased production of H(2)S in hypoxia and exogenous sulfide cannot produce the same effect on the carotid bodies and breathing. While the effects of the endogenous H(2)S on breathing remains to be established, the effects exogenous sulfide can be accounted for by its long established toxicity on cytochrome C oxidase. PMID:22001444

Haouzi, Philippe; Bell, Harold; Van de Louw, Andry

2011-12-15

245

Mechanism analysis of improved DLC films friction behaviors with liquid sulfidation treatment  

NASA Astrophysics Data System (ADS)

Diamond like carbon (DLC) films were treated by liquid sulfidation to improve their friction behaviors. Friction behaviors of DLC films were experimentally evaluated in ambient air under dry friction using GCr15 steel ball sliding over DLC-coated steel flat in a ball-on-disk tribometer system. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were applied to identify the chemical composition and structure of DLC films. It was found that the content of sp2 carbon bond increased and G peak shifted to high wave number after sulfidation treatment. The measurement results showed that sulfur atoms were chemically bonded and the graphitization occurred in the treated DLC films. It was indicated that the treated DLC films exhibited much better friction behaviors than the untreated films, especially for DLC films deposited with high nitrogen ratio. In this paper, we proposed the possible sulfidation mechanism of sulfurized DLC films. Sulfidation mechanism is postulated that thiourea reacted with oxygen to form sulfur-containing organic compounds which included CSSC, CSOH and (NH2)NHdbnd CSO2H and surface diffusion during sulfidation treatment. The anti-friction behaviors of the treated DLC films can be attributed to the production of the compounds containing sulfur on the DLC film surface, the reduce of oxygen content and the presence of graphitization of DLC films.

Zeng, Qunfeng; Yu, Fei; Dong, Guangneng; Mao, Junhong

2012-10-01

246

Liquid Hydrogen Target Experience at SLAC  

SciTech Connect

Liquid hydrogen targets have played a vital role in the physics program at SLAC for the past 40 years. These targets have ranged from small ''beer can'' targets to the 1.5 m long E158 target that was capable of absorbing up to 800 W without any significant density changes. Successful use of these targets has required the development of thin wall designs, liquid hydrogen pumps, remote positioning and alignment systems, safety systems, control and data acquisition systems, cryogenic cooling circuits and heat exchangers. Detailed operating procedures have been created to ensure safety and operational reliability. This paper surveys the evolution of liquid hydrogen targets at SLAC and discusses advances in several of the enabling technologies that made these targets possible.

Weisend, J.G.; Boyce, R.; Candia, A.; Kaminskas, W.; Mark, J.; Racine, M.; St. Lorant, S.; Weber, T.; /SLAC; Arnold, R.; Bosted, P.; /Massachusetts U., Amherst; Carr, R.; Gao, J.; Jones, C.E.; McKeown, R.; /Caltech

2005-08-29

247

Hydrogen Evolution Using Palladium Sulfide (PdS) Nanocorals as Photoanodes in Aqueous Solution.  

PubMed

Palladium sulfide (PdS) nanostructures are proposed to be used as photoanodes in photoelectrochemical cells (PECs) for hydrogen evolution due to their adequate transport and optical properties shown in previous works. Here, a complete morphological and electrochemical characterization of PdS films has been performed by different techniques. PdS flatband potential (Vfb = -0.65 ± 0.05 V vs NHE) was determined by electrochemical impedance spectroscopy measurements in aqueous Na2SO3 electrolyte, providing a description of the energy levels scheme at the electrolyte-semiconductor interface. This energy levels scheme confirms PdS as a compound able to photogenerate hydrogen in a PEC. At last, photogenerated hydrogen rates are measured continuously by mass spectrometry as a function of the external bias potential under illumination, reaching values up to 4.4 ?molH2/h at 0.3 V vs Ag/AgCl. PMID:25340641

Barawi, M; Ferrer, I J; Ares, J R; Sánchez, C

2014-11-26

248

Endurance materials for hydrogen sulfide splitting in electrolytic cell  

NASA Astrophysics Data System (ADS)

This study describes the development of a novel thin membrane exchange assembly (MEA) from a solid acid material, cesium hydrogen sulfate (CsHSO 4), and from a composite anode electrocatalyst for electrolytic splitting of (100%) H2S feed content gas operating at 135 kPa and 150°C. A new class of anode electrocatalyst with the general composition, RuO 2/CoS2, and an improved proton conductor, CsHSO4, have shown great stability and desired properties at typical operating conditions. This configuration demonstrated stable electrochemical operation for 24 h with a (100%) H2S fuel stream at 423 K. This same system showed a maximum current density of (19 mA/cm2) at 900 mV. The performance of this new anode electrocatalyst when compared to that of Pt black investigated in a previous study showed an overall superiority in application. We have achieved a 30% reduction in the overall system performance by fabricating a thin (200 microm) CsHSO4 electrolyte, which reduced the whole MEA thickness from 2.3 mm to 500 microm. The result of permeability measurements proved that this thin solid electrolyte is impermeable to H 2S gas and physical integrity was preserved throughout the experimental period. Further resistance losses were compensated by using a high energy planetary milling system to enhance the ionic conductivity of CsHSO4 . The difference in stability and electrochemical performance of these cells compared to that of Pt anode based systems is directly attributable to the anode materials developed in this project. Factorial experiments were used to characterize the effect of controllable process variables (electrolyte thickness, time, age of the electrolyte) on the cell current density and interfacial polarization resistances. As expected, cell current density and interfacial polarization resistances were a function of electrolyte thickness and age. Nevertheless, the effect of electrolyte thickness has a more prominent effect on the measured parameters. In addition, these experiments were used to identify regions of optimum system performance. Tafel plots were constructed to investigate the kinetic behavior of various anode based electrocatalysts. Exchange current densities, which are directly a measure of the electrochemical reaction, increased with RuO2/CoS 2-based anodes. These experiments also suggested that high levels of feed utilization were possible using these materials. This was an impressive result considering the drastic improvement in electrochemical performance, current density, and sulfur tolerance compared to the other anode configurations.

Mbah, Jonathan Chinwendu

249

Crash test of a liquid hydrogen automobile  

NASA Technical Reports Server (NTRS)

Details of the conversion of a U.S. Postal Service mail truck to hydrogen-fueled operation are given. Specific reference is made to design safety considerations. A traffic accident is described that caused the mail truck (mounted on a trailer) to turn on its side at approximately 20 mph and to finally slide to a stop and turn upside down. No one was injured, and there was essentially no damage to the liquid hydrogen fuel system. The mail truck was driven away from the scene of the accident. Suggestions to insure the safety of hydrogen-fueled experimental vehicles are made.

Finegold, J. G.; Van Vorst, W. D.

1976-01-01

250

High temperature electrochemical removal of hydrogen sulfide from synthetic coal gas streams: Material issues  

SciTech Connect

An advanced process for the separation of hydrogen sulfide from coal gasification product streams through an electrochemical membrane is presently being perfected. Hydrogen sulfide is removed from the syn-gas stream, split into hydrogen (enriching the exiting syn-gas) and sulfur (condensed from an inert sweep gas stream). The process allows removal of H{sub 2}S without cooling the gas stream or incurring pressure loss through the separator. The high operating temperature, flow through design, and capability of selective H{sub 2}S removal and direct production of elemental sulfur offered by this process provide several advantages over existing and development H{sub 2}S removal technologies. The electrochemical membrane process for H{sub 2}S removal from coal gas has proven successful, showing effective removal of H{sub 2}S down to 100 ppm and for polishing to less than 1 ppm, which is the upper limit for the Molten Carbonate Fuel Cell (MCFC) to operate efficiently. 90% removal has been evidenced with an inlet concentration of 20 ppm, testing the most stringent application of this concept; however, some materials problems remain.

Robinson, J.S.; Winnick, J. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Chemical Engineering

1994-12-31

251

EXTRACTION AND QUANTITATIVE ANALYSIS OF ELEMENTAL SULFUR FROM SULFIDE MINERAL SURFACES BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY. (R826189)  

EPA Science Inventory

A simple method for the quantitative determination of elemental sulfur on oxidized sulfide minerals is described. Extraction of elemental sulfur in perchloroethylene and subsequent analysis with high-performance liquid chromatography were used to ascertain the total elemental ...

252

Release of hydrogen sulfide by asteroid impacts in Black Sea and risks for inland human population.  

PubMed

The hydrogen sulfide rich waters of the Black Sea pose a potential danger for the surrounding land regions. The impact of an asteroid may cause a catastrophic poisonous gas release in the atmosphere. Some effects of this last phenomenon on the Eastern Black Sea coastal regions are evaluated in this article. Two simple models are proposed to describe the generation of the H(2)S cloud. The initial diameter of the cloud depends on asteroid size. The initial thickness of the cloud depends, in addition, on sea depth at impact location. The wind speed plays an important role in H(2)S cloud dynamics. At 10 m/s wind-speed the cloud margins may be seen at about 150 km from impact location in about 3.2 h. The maximum distance traveled by the hydrogen sulfide cloud increases by increasing the asteroid size and wind speed. The influence of the impact position on the distance traveled by hydrogen sulfide clouds is rather weak, as far as the seawater depth does not change significantly. Two values are considered when referring to the effect of hydrogen sulfide concentrations on humans: the lower concentration limit of 19.88 ppm (which corresponds to fatigue, loss of appetite, headache, irritability, poor memory, dizziness) and the upper concentration limit of 497 ppm (which corresponds to death after single exposures). The land surface area covered by the H(2)S cloud generated by a 1000 m size asteroid during the run-in ranges between about 6080 and 11,520 km(2). This may affect between 145,000 and 276,000 people. When a 250 m size asteroid is considered, the covered land surface area ranges between about 840 and 1,890 km(2) and between 20,000 and 45,000 people may be affected. In case of a 70 m size asteroid, the cloud covers up to 105 km(2) of land during the run-in. This may affect about 2500 people. These are moderate estimates. They do not include the urban population and may be 10 times underestimated for some particular wind directions. General recommendations to diminish the social effects of the impacts are presented. PMID:17696133

Badescu, Viorel

2007-10-01

253

GYY4137, a novel hydrogen sulfide-releasing molecule, protects against endotoxic shock in the rat  

Microsoft Academic Search

GYY4137 (morpholin-4-ium-4-methoxyphenyl(morpholino) phosphinodithioate) is a slow-releasing hydrogen sulfide (H2S) donor. Administration of GYY4137 (50 mg\\/kg, iv) to anesthetized rats 10 min after lipopolysaccharide (LPS; 4 mg\\/kg, iv) decreased the slowly developing hypotension. GYY4137 inhibited LPS-induced TNF-? production in rat blood and reduced the LPS-evoked rise in NF-?B activation, inducible nitric oxide synthase\\/cyclooxygenase-2 expression, and generation of PGE2 and nitrate\\/nitrite in RAW 264.7 macrophages.

Ling Li; Manuel Salto-Tellez; Choon-Hong Tan; Matthew Whiteman; Philip K. Moore

2009-01-01

254

Hydrogen Sulfide Attenuates Carbon Tetrachloride-Induced Hepatotoxicity, Liver Cirrhosis and Portal Hypertension in Rats  

Microsoft Academic Search

BackgroundHydrogen sulfide (H2S) displays vasodilative, anti-oxidative, anti-inflammatory and cytoprotective activities. Impaired production of H2S contributes to the increased intrahepatic resistance in cirrhotic livers. The study aimed to investigate the roles of H2S in carbon tetrachloride (CCl4)-induced hepatotoxicity, cirrhosis and portal hypertension.Methods and FindingsSodium hydrosulfide (NaHS), a donor of H2S, and DL-propargylglycine (PAG), an irreversible inhibitor of cystathionine ?-lyase (CSE), were

Gang Tan; Shangha Pan; Jie Li; Xuesong Dong; Kai Kang; Mingyan Zhao; Xian Jiang; Jagat R. Kanwar; Haiquan Qiao; Hongchi Jiang; Xueying Sun; Antonio Bertoletti

2011-01-01

255

Polyaniline nanowires-gold nanoparticles hybrid network based chemiresistive hydrogen sulfide sensor  

NASA Astrophysics Data System (ADS)

We report a sensitive, selective, and fast responding room temperature chemiresistive sensor for hydrogen sulfide detection and quantification using polyaniline nanowires-gold nanoparticles hybrid network. The sensor was fabricated by facile electrochemical technique. Initially, polyaniline nanowires with a diameter of 250-320 nm bridging the gap between a pair of microfabricated gold electrodes were synthesized using templateless electrochemical polymerization using a two step galvanostatic technique. Polyaniline nanowires were then electrochemically functionalized with gold nanoparticles using cyclic voltammetry technique. These chemiresistive sensors show an excellent limit of detection (0.1 ppb), wide dynamic range (0.1-100 ppb), and very good selectivity and reproducibility.

Shirsat, Mahendra D.; Bangar, Mangesh A.; Deshusses, Marc A.; Myung, Nosang V.; Mulchandani, Ashok

2009-02-01

256

Evaluation of thiosulfate as a substitute for hydrogen sulfide in sour corrosion fatigue studies  

NASA Astrophysics Data System (ADS)

This work evaluates the possibility of replacing hydrogen sulfide (H 2S) with thiosulfate anion (S2O32- ) in sour corrosion fatigue studies. H2S increases the corrosion fatigue crack growth rate (FCGR) and can be present in carbon steel risers and flowlines used in off-shore oil production. Corrosion tests with gaseous H2S require special facilities with safety features, because H2S is a toxic and flammable gas. The possibility of replacing H2S with S2O32-, a non-toxic anion, for studying stress corrosion cracking of stainless and carbon steels in H2S solutions was first proposed by Tsujikawa et al. ( Tsujikawa et al., Corrosion, 1993. 49(5): p. 409-419). In this dissertation, Tsujikawa work will be extended to sour corrosion fatigue of carbon steels. H2S testing is often conducted in deareated condition to avoid oxygen reaction with sulfide that yields sulfur and to mimic oil production conditions. Nitrogen deareation was also adopted in S2O3 2- testing, and gas exiting the cell was forced through a sodium hydroxide trap. Measurements of the sulfide content of this trap were used to estimate the partial pressure of H2S in nitrogen, and Henry's law was used to estimate the content of H2S in the solution in the cell. H2S was produced by a redox reaction of S2O 32-, which required electrons from carbon steel corrosion. This reaction is spontaneous at the open circuit potential of steel. Therefore, H2S concentration was expected to be maximum at the steel surface, and this concentration was estimated by a mass balance analysis. Carbon steel specimens exposed to S2O32- containing solutions developed a film on their surface, composed by iron sulfide and cementite. The film was not passivating and a good conductor of electrons. Hydrogen permeation experiments proved that this film controls the rate of hydrogen absorption of steels exposed to thiosulfate containing solutions. The absorption of hydrogen in S2O3 2- solutions was compared with the absorption of hydrogen in solutions saturated with different H2S partial pressures. The partial pressure was selected so that the concentration of H2S in the solution saturated with the gas would be the same as that reached in the surface of steel freely corroding in the thiosulfate solution. For solutions obtained by bubbling H2S, the rate of hydrogen absorption increased with the partial pressure of the gas, but the rate of hydrogen absorption reached a maximum at 10-3 M S2O3 2-, despite the surface concentration of H2S increased with the concentration of S2O32-. This effect was associated with the formation of thicker films, which inhibited the absorption of hydrogen. FCGR were evaluated at constant stress intensity factor range. Crack length was monitored in-situ by the direct current potential drop (DCPD) method. FCGR increased with the partial pressure of H2S in nitrogen. FCGR was controlled not only by the amount of hydrogen present in the steel, but also by inhibiting contributions like crack closure and crack tip blunting. FCGR in dilute thiosulfate solutions was near that measured in a solution saturated with a partial pressure of H2S equal to 0.56 kPa, in accord with hydrogen permeation results.

Kappes, Mariano Alberto

257

Liquid Hydrogen Consumption During Space Shuttle Program  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the issue of liquid hydrogen consumption and the points of its loss in prior to the shuttle launch. It traces the movement of the fuel from the purchase to the on-board quantity and the loss that results in 54.6 of the purchased quantity being on board the Shuttle.

Partridge, Jonathan K.

2011-01-01

258

14 CFR 420.66 - Separation distance requirements for storage of hydrogen peroxide, hydrazine, and liquid hydrogen...  

...storage of hydrogen peroxide, hydrazine, and liquid hydrogen and any incompatible energetic liquids stored within an intraline distance. 420...storage of hydrogen peroxide, hydrazine, and liquid hydrogen and any incompatible energetic...

2014-01-01

259

14 CFR 420.66 - Separation distance requirements for storage of hydrogen peroxide, hydrazine, and liquid hydrogen...  

Code of Federal Regulations, 2013 CFR

...storage of hydrogen peroxide, hydrazine, and liquid hydrogen and any incompatible energetic liquids stored within an intraline distance. 420...storage of hydrogen peroxide, hydrazine, and liquid hydrogen and any incompatible energetic...

2013-01-01

260

Removing hydrogen sulfide from wastewater treatment facilities` air process streams with a biotrickling filter  

SciTech Connect

Control of hydrogen sulfide (H{sub 2}S) and odor emissions has been a major consideration for many wastewater treatment plants. Many different methods have been and are currently being used for H{sub 2}S and odor control. Most of the current methods involve absorption of H{sub 2}S and odors into a liquid solution or adsorption onto a solid matrix. These methods are either expensive or if not operated correctly can be inefficient. The Los Angeles County Sanitation Districts have developed a biological method to remove odors and H{sub 2}S from different off-gas streams at its main wastewater treatment plant, the Joint Water Pollution Control Plant (JWPCP). This treatment method, which is known as a biotrickling filter, uses a packed contactor device in which the air to be treated is blown through the packing. The H{sub 2}S and odor is removed by a scrubbing solution containing bacteria that is trickled down from the top of the contactor. Different types of column packing media were tested, with a rock-based media being the most effective. The rock media allowed the biotrickling filter to get over 98 percent removal of inlet H{sub 2}S, as long as H{sub 2}S loadings did not exceed 39 g-H{sub 2}S/m{sup 3}-hr (1.1 g-H{sub 2}S/ft{sup 3}-hr). Odor panel analyses indicated that inlet odors were reduced by 99 percent by the biotrickling filter. Due to the success of the research work, a full scale biotrickling filter is being put into operation at the JWPCP. The unit will replace existing caustic scrubbers and will be much less expensive to operate. Current costs to operate a caustic scrubber at the JWPCP is about $1,150 per million m{sup 3} ($33.00 per million ft3) of air treated. The biotrickling filter operational costs would be about one-fifth or $240 per million m{sup 3} ($7.00 per million ft{sup 3}) of air treated.

Morton, R.L.; Caballero, R.C. [County Sanitation Districts of Los Angeles County, Carson, CA (United States)

1997-12-31

261

Liquid Hydrogen Sensor Considerations for Space Exploration  

NASA Technical Reports Server (NTRS)

The on-orbit management of liquid hydrogen planned for the return to the moon will introduce new considerations not encountered in previous missions. This paper identifies critical liquid hydrogen sensing needs from the perspective of reliable on-orbit cryogenic fluid management, and contrasts the fundamental differences in fluid and thermodynamic behavior for ground-based versus on-orbit conditions. Opportunities for advanced sensor development and implementation are explored in the context of critical Exploration Architecture operations such as on-orbit storage, docking, and trans-lunar injection burn. Key sensing needs relative to these operations are also examined, including: liquid/vapor detection, thermodynamic condition monitoring, mass gauging, and leak detection. Finally, operational aspects of an integrated system health management approach are discussed to highlight the potential impact on mission success.

Moran, Matthew E.

2006-01-01

262

Unmodified versus caustics-impregnated carbons for control of hydrogen sulfide emissions from sewage treatment plants  

SciTech Connect

Unmodified and caustic-impregnated carbons were compared as adsorbents for hydrogen sulfide in the North River Water Pollution Control Plant in New York City over a period of 2 years. The carbons were characterized using accelerated H{sub 2}S breakthrough capacity tests, sorption of nitrogen, potentiometric titration, and thermal analysis. The accelerated laboratory tests indicate that the initial capacity of caustic-impregnated carbons exceeds that of unmodified carbon, but the nature of real-life challenge streams, particularly their lower H{sub 2}S concentrations, nullifies this advantage. As the caustic content of the impregnated carbon is consumed, the situation reverses, and the unmodified carbon becomes more effective. When the concentration of H{sub 2}S is low, the developed surface area and pore volume along with the affinity to retain water create a favorable environment for dissociative adsorption of hydrogen sulfide and its oxidation to elemental sulfur, S{sup 4+}, and S{sup 6+}. In the case of the caustic carbon, the catalytic impact of the carbon surface is limited, and its good performance lasts only while active base is present. The results also show the significant differences in performance of unmodified carbons due to combined effects of their porosity and surface chemistry.

Bandosz, T.J.; Bagreev, A.; Adib, F.; Turk, A.

2000-03-15

263

Equilibrium hydrate formation conditions for hydrogen sulfide, carbon dioxide, and ethane in aqueous solutions of ethylene glycol and sodium chloride  

SciTech Connect

Natural gas components such as hydrogen sulfide, carbon dioxide, and ethane form gas hydrates of structure I under suitable temperature and pressure conditions. Information on such conditions is vital to the oil and gas industry in order to design and operate processing equipment and pipelines so that hydrate formation is avoided. Incipient equilibrium hydrate formation conditions for hydrogen sulfide, carbon dioxide, and ethane in aqueous solutions of ethylene glycol and sodium chloride were experimentally obtained in the temperature range 264--290 K and the pressure range 0.23--3.18 MPa. A variable-volume sapphire cell was used for the measurements.

Majumdar, A.; Mahmoodaghdam, E.; Bishnoi, P.R.

2000-02-01

264

Single Membrane Reactor Configuration for Separation of Hydrogen, Carbon Dioxide and Hydrogen Sulfide  

Microsoft Academic Search

The objective of the project was to develop a novel complementary membrane reactor process that can consolidate two or more downstream unit operations of a coal gasification system into a single module for production of a pure stream of hydrogen and a pure stream of carbon dioxide. The overall goals were to achieve higher hydrogen production efficiencies, lower capital costs

Micheal Roberts; Robert Zabransky; Shain Doong; Jerry Lin

2008-01-01

265

Small, high pressure liquid hydrogen turbopump  

NASA Technical Reports Server (NTRS)

A high pressure, low capacity, liquid hydrogen turbopump was designed, fabricated, and tested. The design configuration of the turbopump is summarized and the results of the analytical and test efforts are presented. Approaches used to pin point the cause of poor suction performance with the original design are described and performance data are included with an axial inlet design which results in excellent suction capability.

Csomor, A.; Warren, D. J.

1980-01-01

266

Liquid hydrogen flow problems in Kiwi reactors  

SciTech Connect

The Kiwi series of reactors were the first ones tested in the US Rover Program in the development of nuclear rocket engines for space propulsion. The early experiments with liquid hydrogen showed that parallel flow systems were prone to uneven flow distributions and violent fluctuations in pressure and flow that were capable of destroying a reactor core. Kiwi flow distribution problems were solved by using multiple feed lines into the nozzle cooling system and carefully balancing impedance among them. The violent pressure and flow fluctuations were eliminated after their cause was identified as resonance phenomena driven by the response to flow disturbances of heat transfer through a superheated hydrogen layer. Smooth flow operations were assured by rapidly bringing operating pressures beyond several times the critical pressure of hydrogen. After this initial rough start, solid core nuclear rocket engines successfully passed milestones of achievements during the remainder of the Rover program.

Thurston, R.S.

1992-09-01

267

KEY COMPARISON: International Comparison CCQM-K41: Hydrogen sulfide in nitrogen  

NASA Astrophysics Data System (ADS)

This key comparison was intended to compare the capabilities for the preparation and value assignment of gas standards for hydrogen sulfide in nitrogen, maintained at the participating national metrology institutes. The range of the nominal amount-of-substance fractions of the comparison standard is 10 µmol/mol, which is close to regulatory levels in most countries. The measurements in this key comparison took place in 2005. There were 7 participants. The KCRV was calculated from the participants' data, and thus represents a consensus value. This was necessary due to the fact that the cylinders could not be prepared gravimetrically as hydrogen sulfide may be absorbed onto the walls of the cylinder, and has been shown to be unstable in cylinders at the comparison concentration. Thus the gas mixtures were procured from a vendor as a homogeneous lot of 12 cylinders, analyzed by the coordinating laboratory for 6 months to determine stability, and then those determined to be stable were shipped to the participants for analysis. After analysis, the cylinders were returned to the coordinating laboratory for reanalysis. Through this protocol the coordinating laboratory could track stability. In parallel, the coordinating laboratory also analyzed a stable reference, a hydrogen sulfide gas mixture that had been shown to be stable over many years. Using the lot stability data, the participant's analytical results, and the coordinating laboratories' analysis of the stable reference, a consensus value could be calculated which represents the concentration of the stable reference. The key comparison demonstrated that the results of the laboratories agreed within 0.5% relative to the consensus value. A subset of 6 participants' results agreed with the consensus value to better than 0.25%. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Guenther, Franklin R.; Miller, Walter R.; Duewer, David L.; Heo, Gwi Suk; Kim, Yong-Doo; van der Veen, Adriaan M. H.; Konopelko, Leonid; Kustikov, Yury; Shor, Nina; Brookes, Chris; Milton, Martin; Dias, Florbela; Qiao, Han

2007-01-01

268

Electrically Conducting Polymer-Copper Sulphide Composite Films, Preparation by Treatment of Polymer-Copper (2) Acetate Composites with Hydrogen Sulfide  

NASA Technical Reports Server (NTRS)

Polymer copper sulfide composite films were prepared by treatment of polymer poly(vinyl chloride), poly(acrylonitrile), copolymer of vinyl chloride and vinyl acetate (90:10), and ABS resin copper (2) acetate composites with hydrogen sulfide. The films showed electrical conductivity higher than 0.015 S/cm when they contained more than 20 wt percent of copper sulfide. A poly(acrylonitrile)-copper sulfide composite film containing 40 to 50 wt percent of copper sulfide showed electrical conductivity of 10 to 150.0 S/cm and had relatively high mechanical strength to be used in practical purposes.

Yamamoto, Takakazu; Kamigaki, Takahira; Kubota, Etsuo

1988-01-01

269

Study of the Mechanism of the Hydrogen Sulfide/Dolomite Reaction. Quarterly Report, October--December 1976.  

National Technical Information Service (NTIS)

A high pressure thermogravimetric analyzer system incorporating a duPont 990 Thermal Analyzer, a reactor tube, and a gas feed system has been completed. The design of a humidifier and a hydrogen sulfide trap to be used in later experiments has been comple...

1977-01-01

270

Textural Equilibria of Iron Sulfide Liquids in Partly Molten Silicate Aggregates and Their Relevance to Core Formation Scenarios  

NASA Technical Reports Server (NTRS)

The influence of the coexistence of silicate and iron sulfide melts on the wetting of mantle olivine by iron sulfide melt is investigated. The dihedral angle between iron alloy and olivine is unaffected by the presence of silicate melt at 1.5 GPa and 1370-1410 C and is much greater than the maximum allowable dihedral angle for melt connectivity at low melt fractions. In experimental charges where silicate and sulfide melt occupy the same melt pocket, the sulfide melt adheres to olivine grain faces rather than forming discrete droplets. The relative interfacial energy between iron sulfide and basaltic silicate melt is lower than that of iron sulfide with olivine, but the contrast is not sufficient for basaltic silicate melt to wet FeS-olivine grain boundaries. This result implies that very large silicate melt fractions are necessary to mobilize iron sulfide melts in partially molten silicate phase assemblages. Therefore segregation of Fe-rich metallic melts by porous flow at low melt fraction is not a likely process for metal separation. The experiments also investigated the influence of the presence of a thermal gradient on sulfide melt migration. Although the sulfide melt can not migrate through the olivine network by porous flow, evidence in the experiments indicates mobility of sulfide through the interconnected silicate melt network. The sulfide melt pools in contact with silicate melt at the hot, top part of the experimental charges grow over time at the expense of the silicate melt pools in the cooler part of the charge. This points to a diffusive transport mechanism for local sulfide redistribution. We review literature data on metal-olivine wetting angles and find that the metal composition has a dominant influence on the wetting behavior of a metallic liquid on an olivine matrix. Iron-rich metallic liquid compositions are characterized by large dihedral angles (less than 90 deg). The metal-olivine dihedral angle decreases with increasing amounts of dissolved light element (S, C, O). For light element contents in excess of approx. 59 at %, the dihedral angle approaches 60 deg., and the wetting behavior of a metallic liquid is similar to that of a silicate liquid.

Holzheid, Astrid; Schmitz, Mark D.; Grove, Timothy L.

2000-01-01

271

Gas phase recovery of hydrogen sulfide contaminated polymer electrolyte membrane fuel cells  

NASA Astrophysics Data System (ADS)

The effect of hydrogen sulfide (H2S) on the anode of a polymer electrolyte membrane fuel cell (PEMFC) and the gas phase recovery of the contaminated PEMFC using ozone (O3) were studied. Experiments were performed on fuel cell electrodes both in an aqueous electrolyte and within an operating fuel cell. The ex-situ analyses of a fresh electrode; a H2S contaminated electrode (23 ?molH2S cm-2); and the contaminated electrode cleaned with O3 shows that all sulfide can be removed within 900 s at room temperature. Online gas analysis of the recovery process confirms the recovery time required as around 720 s. Similarly, performance studies of an H2S contaminated PEMFC shows that complete rejuvenation occurs following 600-900 s O3 treatment at room temperature. The cleaning process involves both electrochemical oxidation (facilitated by the high equilibrium potential of the O3 reduction process) and direct chemical oxidation of the contaminant. The O3 cleaning process is more efficient than the external polarization of the single cell at 1.6 V. Application of O3 at room temperature limits the amount of carbon corrosion. Room temperature O3 treatment of poisoned fuel cell stacks may offer an efficient and quick remediation method to recover otherwise inoperable systems.

Kakati, Biraj Kumar; Kucernak, Anthony R. J.

2014-04-01

272

The Effect of Hydrogen Sulfide Donors on Lipopolysaccharide-Induced Formation of Inflammatory Mediators in Macrophages  

PubMed Central

Abstract The role of hydrogen sulfide (H2S) in inflammation is controversial, with both pro- and antiinflammatory effects documented. Many studies have used simple sulfide salts as the source of H2S, which give a rapid bolus of H2S in aqueous solutions and thus do not accurately reflect the enzymatic generation of H2S. We therefore compared the effects of sodium hydrosulfide and a novel slow-releasing H2S donor (GYY4137) on the release of pro- and antiinflammatory mediators in lipopolysaccharide (LPS)-treated murine RAW264.7 macrophages. For the first time, we show that GYY4137 significantly and concentration-dependently inhibits LPS-induced release of proinflammatory mediators such as IL-1?, IL-6, TNF-?, nitric oxide (•NO), and PGE2 but increased the synthesis of the antiinflammatory chemokine IL-10 through NF-?B/ATF-2/HSP-27–dependent pathways. In contrast, NaHS elicited a biphasic effect on proinflammatory mediators and, at high concentrations, increased the synthesis of IL-1?, IL-6, NO, PGE2 and TNF-?. This study clearly shows that the effects of H2S on the inflammatory process are complex and dependent not only on H2S concentration but also on the rate of H2S generation. This study may also explain some of the apparent discrepancies in the literature regarding the pro- versus antiinflammatory role of H2S. Antioxid. Redox Signal. 12, 1147–1154. PMID:19769459

Whiteman, Matthew; Li, Ling; Rose, Peter; Tan, Choon-Hong; Parkinson, David B.

2010-01-01

273

The effect of hydrogen sulfide donors on lipopolysaccharide-induced formation of inflammatory mediators in macrophages.  

PubMed

The role of hydrogen sulfide (H(2)S) in inflammation is controversial, with both pro- and antiinflammatory effects documented. Many studies have used simple sulfide salts as the source of H(2)S, which give a rapid bolus of H(2)S in aqueous solutions and thus do not accurately reflect the enzymatic generation of H(2)S. We therefore compared the effects of sodium hydrosulfide and a novel slow-releasing H(2)S donor (GYY4137) on the release of pro- and antiinflammatory mediators in lipopolysaccharide (LPS)-treated murine RAW264.7 macrophages. For the first time, we show that GYY4137 significantly and concentration-dependently inhibits LPS-induced release of proinflammatory mediators such as IL-1beta, IL-6, TNF-alpha, nitric oxide (*NO), and PGE(2) but increased the synthesis of the antiinflammatory chemokine IL-10 through NF-kappaB/ATF-2/HSP-27-dependent pathways. In contrast, NaHS elicited a biphasic effect on proinflammatory mediators and, at high concentrations, increased the synthesis of IL-1beta, IL-6, NO, PGE(2) and TNF-alpha. This study clearly shows that the effects of H(2)S on the inflammatory process are complex and dependent not only on H(2)S concentration but also on the rate of H(2)S generation. This study may also explain some of the apparent discrepancies in the literature regarding the pro- versus antiinflammatory role of H(2)S. PMID:19769459

Whiteman, Matthew; Li, Ling; Rose, Peter; Tan, Choon-Hong; Parkinson, David B; Moore, Philip K

2010-05-15

274

High temperature removal of hydrogen sulfide using an N-150 sorbent.  

PubMed

In this study, an N-150 sorbent was used as a high temperature desulfurization sorbent for the removal of hydrogen sulfide from coal gas in a fixed bed reactor. The results indicate that the N-150 sorbent could be used for H(2)S removal in the tested temperature ranges. Regeneration test also reveals that utilization of the N-150 sorbent maintains up to 85% compared to the fresh sorbent. No significant degeneration occurs on the N-150 sorbent. In addition, various concentrations of H(2)S, H(2) and CO were also considered in the performance test of the N-150 sorbent. Except for H(2)S, H(2) and CO act the important roles in the high temperature desulfurization. By increasing the H(2) concentration, the sulfur capacity of the sorbent decreases and an adverse result is observed in the case of increasing CO concentration. This can be explained via water-shift reaction. On the basis of the instrument analysis, X-ray powder diffraction determination and SEM images with EDS spectrum characterization, residual sulfur is found in the regenerated N-150 sorbent and this sulfur species is sulfate which resulted by incomplete regeneration. The sulfate formation and sintering effect are major reasons to cause activity loss in the sulfidation/regeneration cycles. PMID:15511585

Ko, T H; Chu, H; Chaung, L K; Tseng, T K

2004-10-18

275

Hydrogen sulfide-releasing aspirin inhibits the growth of leukemic Jurkat cells and modulates ?-catenin expression  

PubMed Central

Hydrogen sulfide-releasing aspirin (HS-ASA) is a novel compound with potential against cancer. It inhibited the growth of Jurkat T-leukemia cells with an IC50 of 1.9 ± 0.2 µM whereas that of ASA was >5000 µM. It dose-dependently inhibited proliferation and induced apoptosis in these cells, causing a G0/G1 cell cycle arrest. HS-ASA down-regulated ?-catenin protein levels and reduced mRNA and protein expression of ?-catenin/TCF downstream target genes cyclinD1 and c-myc. Aspirin up to 5 mM had no effect on ?-catenin expression. HS-ASA also increased caspase-3 protein levels and dose-dependently increased its activity. These effects were substantially blocked by z-VAD-fmk, a pan-caspase inhibitor. PMID:23896061

Chattopadhyay, Mitali; Nath, Niharika; Kodela, Ravinder; Sobocki, Tomasz; Metkar, Shalaka; Gan, Zong Yuan; Kashfi, Khosrow

2013-01-01

276

["Waste gas is not waste": advance in the research of hydrogen sulfide].  

PubMed

The discovery of endogenous gasotransmitters puts forwards a new concept, "waste gas is not waste". Hydrogen sulfide (H(2)S) is considered as a new member of gasotransmitter family, following nitric oxide (NO) and carbon monoxide (CO). Recently, the understanding of H(2)S biological effect and its mechanisms has been deepened, especially the pathophysiological significance of H(2)S in the various diseases such as cardiovascular diseases, neurological diseases, respiratory diseases, endocrine diseases, etc. This article reviews recent progress of basic, clinical and pharmacological researches related to endogenous H(2)S, including the regulatory effects of H(2)S on the cell proliferation, apoptosis, inflammation, angiogenesis and ion channels, the role of endogenous H(2)S pathway in the pathogenesis of various diseases, as well as the study of the H(2)S donor and H(2)S-related drugs. PMID:21170494

Jin, Hong-Fang; DU, Jun-Bao; Tang, Chao-Shu

2010-12-25

277

Low-Power, Fast, Selective Nanoparticle-based Hydrogen Sulfide Gas Sensor  

NASA Astrophysics Data System (ADS)

We demonstrate a small, fast, low-cost, low-power, highly sensitive and selective nanomaterials-based gas sensor that can operate under extreme temperature and humidity conditions. Gas sensors in industrial use today, on the other hand, suffer from high cost, high power consumption, lack of portability and/or inoperability in very dry or hot regions. The sensing substrate is a network of nanoparticles whose conductance is monitored. The sensor shows high sensitivity to hydrogen sulfide (H2S), but it does not have significant cross sensitivities to H2O or CH4, two gases likely to be seen in industrial operation, and is not sensitive to the high temperatures also likely to be seen. Such a sensor has the potential to enable significant advances in the fields of personal, broad area, and mobile monitoring of gases, such as environmental pollutants or toxic or flammable gases.

Sussman, Allen; Mickelson, William; Zettl, A.

2012-02-01

278

Increased growth and germination success in plants following hydrogen sulfide administration.  

PubMed

This study presents a novel way of enhancing plant growth through the use of a non-petroleum based product. We report here that exposing either roots or seeds of multicellular plants to extremely low concentrations of dissolved hydrogen sulfide at any stage of life causes statistically significant increases in biomass including higher fruit yield. Individual cells in treated plants were smaller (~13%) than those of controls. Germination success and seedling size increased in, bean, corn, wheat, and pea seeds while time to germination decreases. These findings indicated an important role of H2S as a signaling molecule that can increase the growth rate of all species yet tested. The increased crop yields reported here has the potential to effect the world's agricultural output. PMID:23614010

Dooley, Frederick D; Nair, Suven P; Ward, Peter D

2013-01-01

279

Cobalt sulfide nanosheet/graphene/carbon nanotube nanocomposites as flexible electrodes for hydrogen evolution.  

PubMed

Flexible three-dimensional (3D) nanoarchitectures have received tremendous interest recently because of their potential applications in wearable electronics, roll-up displays, and other devices. The design and fabrication of a flexible and robust electrode based on cobalt sulfide/reduced graphene oxide/carbon nanotube (CoS2 /RGO-CNT) nanocomposites are reported. An efficient hydrothermal process combined with vacuum filtration was used to synthesize such composite architecture, which was then embedded in a porous CNT network. This conductive and robust film is evaluated as electrocatalyst for the hydrogen evolution reaction. The synergistic effect of CoS2 , graphene, and CNTs leads to unique CoS2 /RGO-CNT nanoarchitectures, the HER activity of which is among the highest for non-noble metal electrocatalysts, showing 10?mA?cm(-2) current density at about 142?mV overpotentials and a high electrochemical stability. PMID:25297454

Peng, Shengjie; Li, Linlin; Han, Xiaopeng; Sun, Wenping; Srinivasan, Madhavi; Mhaisalkar, Subodh G; Cheng, Fangyi; Yan, Qingyu; Chen, Jun; Ramakrishna, Seeram

2014-11-10

280

Effects of a hydrogen sulfide donor on spontaneous contractile activity of rat stomach and jejunum.  

PubMed

We studied the effect of sodium hydrosulfite (NaHS), a donor of hydrogen sulfide (H2S), on spontaneous contractive activity of isolated preparations of rat stomach and jejunum under isometric conditions. NaHS in concentrations of 10-200 ?M reduced the amplitude, tonic tension, and frequency of contractions of the preparations. Blockade of K(+) channels with a non-specific antagonist tetraethylammonium (10 mM) increased contraction amplitude in the stomach strip and jejunum segment. The effects of NaHS on all parameters of contractile activity of the stomach and jejunum were fully preserved against the background of tetraethylammonium application. These data suggest that H2S in physiologically relevant concentrations inhibited spontaneous contractile activity of smooth muscle cells in rat stomach and jejunum by reducing the amplitude and frequency of contractions and decreased tonic tension without affecting the function of voltage- and calcium-dependent K(+) channels. PMID:25070160

Shafigullin, M Y; Zefirov, R A; Sabirullina, G I; Zefirov, A L; Sitdikova, G F

2014-07-01

281

Hydrogen Sulfide, the Next Potent Preventive and Therapeutic Agent in Aging and Age-Associated Diseases  

PubMed Central

Hydrogen sulfide (H2S) is the third endogenous signaling gasotransmitter, following nitric oxide and carbon monoxide. It is physiologically generated by cystathionine-?-lyase, cystathionine-?-synthase, and 3-mercaptopyruvate sulfurtransferase. H2S has been gaining increasing attention as an important endogenous signaling molecule because of its significant effects on the cardiovascular and nervous systems. Substantial evidence shows that H2S is involved in aging by inhibiting free-radical reactions, activating SIRT1, and probably interacting with the age-related gene Klotho. Moreover, H2S has been shown to have therapeutic potential in age-associated diseases. This article provides an overview of the physiological functions and effects of H2S in aging and age-associated diseases, and proposes the potential health and therapeutic benefits of H2S. PMID:23297346

Zhang, Yuan; Tang, Zhi-Han; Ren, Zhong; Qu, Shun-Lin; Liu, Mi-Hua; Liu, Lu-Shan

2013-01-01

282

Hydrogen sulfide: a neuromodulator and neuroprotectant in the central nervous system.  

PubMed

Hydrogen sulfide (H2S) used to be known as a toxic gas. However, in the last two decades, accumulating evidence has revealed its role as a bioactive molecule in the biological systems. H2S has relatively high expression in the brain, exerting multiple functions in both health and diseases. It modulates neurotransmission by influencing behaviors of NMDA receptors and second messenger systems including intracellular Ca(2+) concentration and intracellular cAMP levels and so forth. H2S shows potential therapeutic value in several CNS diseases including Alzheimer's disease, Parkinson's disease, ischemic stroke, and traumatic brain injury. As a neuroprotectant, H2S produces antioxidant, anti-inflammatory, and antiapoptotic effects in pathological situations. Sulfhydration of target proteins is an important mechanism underlying these effects. This Review summarizes the current understanding of H2S in the central nervous system, with emphasis on its role as a neuromodulator and a neuroprotectant. PMID:25230373

Zhang, Xingzhou; Bian, Jin-Song

2014-10-15

283

Homocysteine in renovascular complications: hydrogen sulfide is a modulator and plausible anaerobic ATP generator.  

PubMed

Homocysteine (Hcy) is a non-protein amino acid derived from dietary methionine. High levels of Hcy, known as hyperhomocysteinemia (HHcy) is known to cause vascular complications. In the mammalian tissue, Hcy is metabolized by transsulfuration enzymes to produce hydrogen sulfide (H2S). H2S, a pungent smelling gas was previously known for its toxic effects in the central nervous system, recent studies however has revealed protective effects in a variety of diseases including hypertension, diabetes, inflammation, atherosclerosis, and renal disease progression and failure. Interestingly, under stress conditions including hypoxia, H2S can reduce metabolic demand and also act as a substrate for ATP production. This review highlights some of the recent advances in H2S research as a potential therapeutic agent targeting renovascular diseases associated with HHcy. PMID:24963795

Sen, Utpal; Pushpakumar, Sathnur B; Amin, Matthew A; Tyagi, Suresh C

2014-09-15

284

Inhaled hydrogen sulfide protects against lipopolysaccharide-induced acute lung injury in mice  

PubMed Central

Background Local pulmonary and systemic infections can lead to acute lung injury (ALI). The resulting lung damage can evoke lung failure and multiple organ dysfunction associated with increased mortality. Hydrogen sulfide (H2S) appears to represent a new therapeutic approach to ALI. The gas has been shown to mediate potent anti-inflammatory and organ protective effects in vivo. This study was designed to define its potentially protective role in sepsis-induced lung injury. Methods C57BL/6 N mice received lipopolysaccharide (LPS) intranasally in the absence or presence of 80 parts per million H2S. After 6 h, acute lung injury was determined by comparative histology. Bronchoalveolar lavage (BAL) fluid was analyzed for total protein content and differential cell counting. BAL and serum were further analyzed for interleukin-1?, macrophage inflammatory protein-2, and/or myeloperoxidase glycoprotein levels by enzyme-linked immunosorbent assays. Differences between groups were analyzed by one way analysis of variance. Results Histological analysis revealed that LPS instillation led to increased alveolar wall thickening, cellular infiltration, and to an elevated ALI score. In the presence of H2S these changes were not observed despite LPS treatment. Moreover, neutrophil influx, and pro-inflammatory cytokine release were enhanced in BAL fluid of LPS-treated mice, but comparable to control levels in H2S treated mice. In addition, myeloperoxidase levels were increased in serum after LPS challenge and this was prevented by H2S inhalation. Conclusion Inhalation of hydrogen sulfide protects against LPS-induced acute lung injury by attenuating pro-inflammatory responses. PMID:23025523

2012-01-01

285

Hydrogen Sulfide Mitigates Cardiac Remodeling During Myocardial Infarction via Improvement of Angiogenesis  

PubMed Central

Exogenous hydrogen sulfide (H2S) leads to down-regulation of inflammatory responses and provides myocardial protection during acute ischemia/reperfusion injury; however its role during chronic heart failure (CHF) due to myocardial infarction (MI) is yet to be unveiled. We previously reported that H2S inhibits antiangiogenic factors such, as endostatin and angiostatin, but a little is known about its effect on parstatin (a fragment of proteinase-activated receptor-1, PAR-1). We hypothesize that H2S inhibits parstatin formation and promotes VEGF activation, thus promoting angiogenesis and significantly limiting the extent of MI injury. To verify this hypothesis MI was created in 12 week-old male mice by ligation of left anterior descending artery (LAD). Sham surgery was performed except LAD ligation. After the surgery mice were treated with sodium hydrogen sulfide (30 ?mol/l NaHS, a donor for H2S, in drinking water) for 4 weeks. The LV tissue was analyzed for VEGF, flk-1 and flt-1, endostatin, angiostatin and parstatin. The expression of VEGF, flk-1 and flt-1 were significantly increased in treated mice while the level of endostatin, angiostatin and parstatin were decreased compared to in untreated mice. The echocardiography in mice treated with H2S showed the improvement of heart function compared to in untreated mice. The X-ray and Doppler blood flow measurements showed enhancement of cardiac-angiogenesis in mice treated with H2S. This observed cytoprotection was associated with an inhibition of anti-angiogenic proteins and stimulation of angiogenic factors. We established that administration of H2S at the time of MI ameliorated infarct size and preserved LV function during development of MI in mice. These results suggest that H2S is cytoprotective and angioprotective during evolution of MI. PMID:22419888

Qipshidze, Natia; Metreveli, Naira; Mishra, Paras K.; Lominadze, David; Tyagi, Suresh C.

2012-01-01

286

Hydrogen Sulfide in the RVLM and PVN has No Effect on Cardiovascular Regulation  

PubMed Central

Hydrogen sulfide (H2S) is now recognized as an important signaling molecule and has been shown to have vasodilator and cardio-protectant effects. More recently it has been suggested that H2S may also act within the brain to reduce blood pressure (BP). In the present study we have demonstrated the presence of the H2S-producing enzyme, cystathionine-?-synthase (CBS) in the rostral ventrolateral medulla (RVLM), and the hypothalamic paraventricular nucleus (PVN), brain regions with key cardiovascular regulatory functions. The cardiovascular role of H2S was investigated by determining the BP, heart rate (HR), and lumbar sympathetic nerve activity (LSNA) responses elicited by a H2S donor sodium hydrogen sulfide (NaHS) or inhibitors of CBS, microinjected into the RVLM and PVN. In anesthetized Wistar Kyoto rats bilateral microinjections of NaHS (0.2–2000?pmol/side) into the RVLM did not significantly affect BP, HR, or LSNA, compared to vehicle. Similarly, when the CBS inhibitors, amino-oxyacetate (AOA; 0.1–1.0?nmol/side) or hydroxylamine (HA; 0.2–2.0?nmol/side), were administered into the RVLM, there were no significant effects on the cardiovascular variables compared to vehicle. Microinjections into the PVN of NaHS, HA, and AOA had no consistent significant effects on BP, HR, or LSNA compared to vehicle. We also investigated the cardiovascular responses to NaHS microinjected into the RVLM and PVN in spontaneously hypertensive rats. Again, there were no significant effects on BP, HR, and LSNA. Together, these results suggest that H2S in the RVLM and PVN does not have a major role in cardiovascular regulation. PMID:21941511

Streeter, Eloise; Al-Magableh, Mohammad; Hart, Joanne Louise; Badoer, Emilio

2011-01-01

287

Hydrogen bonds in liquid water are broken only fleetingly  

E-print Network

Hydrogen bonds in liquid water are broken only fleetingly J. D. Eaves* , J. J. Loparo* , C. J that the local structure of liquid water has tetrahedral arrangements of molecules ordered by hydrogen bonds, the mechanism by which water molecules switch hydrogen-bonded partners remains unclear. In this mechanism

Geissler, Phillip

288

Experiments on microjets of undercooled liquid hydrogen  

NASA Astrophysics Data System (ADS)

Novel experiments on liquid microjets (filaments) of hydrogen and deuterium, carried out at the Laboratory of Molecular Fluid Dynamics of the IEM, are reported. These filaments, less than 10 microns in diameter, are an ideal medium to produce highly undercooled liquid samples and to investigate the homogeneous solidification process, free from wall effects. The filaments exit from cryogenic capillary nozzles into a vacuum chamber, to cool down very fast by surface evaporation. Finite size radius leads to a temperature gradient across the filament, determined by thermal conductivity, and, possibly, to a velocity gradient as well. The filaments are monitored by laser shadowgraphy, and analyzed by means of high performance Raman spectroscopy. Real-time measurements in the rotational and vibrational spectral regions reveal the structure and temperature along the filaments, allowing to track the crystal growth process. The high spatial resolution of Raman spectroscopy allows observing in situ the structural changes of the liquid microjets, with a time resolution of ˜ 10 ns. The filaments of pure para-H2 can be cooled down to 9 K (65% of its melting point at 13.8 K), while staying liquid, before eventually solidifying into a metastable polymorph. Crystallization kinetics revealed a growth rate of 33 cm/s, much higher than expected for a thermally activated process. The time and spatial control attained in these experiments offers new opportunities for investigating the processes of nonequilibrium phase transformations in undercooled fluids, as well as the propagation of liquid jets into a rarefied gas media.

Fernández, José M.; Kühnel, Matthias; Tejeda, Guzmán; Kalinin, Anton; Grisenti, Robert E.; Montero, Salvador

2012-11-01

289

The inhibition of mitochondrial cytochrome oxidase by the gases carbon monoxide, nitric oxide, hydrogen cyanide and hydrogen sulfide: chemical mechanism and physiological significance  

Microsoft Academic Search

The four gases, nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H2S) and hydrogen cyanide (HCN) all readily inhibit oxygen consumption by mitochondrial cytochrome oxidase. This inhibition\\u000a is responsible for much of their toxicity when they are applied externally to the body. However, recently these gases have\\u000a all been implicated, to greater or lesser extents, in normal cellular signalling events.

Chris E. Cooper; Guy C. Brown

2008-01-01

290

Screen Channel Liquid Acquisition Device Outflow Tests in Liquid Hydrogen  

NASA Technical Reports Server (NTRS)

This paper presents experimental design and test results of the recently concluded 1-g inverted vertical outflow testing of two 325x2300 full scale liquid acquisition device (LAD) channels in liquid hydrogen (LH2). One of the channels had a perforated plate and internal cooling from a thermodynamic vent system (TVS) to enhance performance. The LADs were mounted in a tank to simulate 1-g outflow over a wide range of LH2 temperatures (20.3 - 24.2 K), pressures (100 - 350 kPa), and flow rates (0.010 - 0.055 kg/s). Results indicate that the breakdown point is dominated by liquid temperature, with a second order dependence on mass flow rate through the LAD. The best performance is always achieved in the coldest liquid states for both channels, consistent with bubble point theory. Higher flow rates cause the standard channel to break down relatively earlier than the TVS cooled channel. Both the internal TVS heat exchanger and subcooling the liquid in the propellant tank are shown to significantly improve LAD performance.

Hartwig, Jason W.; Chato, David J.; McQuillen, J. B.; Vera, J.; Kudlac, M. T.; Quinn, F. D.

2013-01-01

291

Effective Hydrogen Generation from the Hydrogen Sulfide Solution by using Stratified Type Photocatalyst  

SciTech Connect

Stratified type photocatalyst with the extremely higher photocatalytic activities can be synthesized by using the chemical reaction between the Na{sub 2}S solution and Cd(OH){sub 2} precursors. This type of photocatalyst has the specific morphology which constructed by the nano-sized and capsule like formed structure, and the metal concentration was gradually changed in its wall. The 'charge gradient' was formed at the metal sulfide and oxide/hydroxide junction in the wall, which favored for the separation of the photo excited electron-hole pair. Consequently, stratified type photocatalyst shows the high catalytic activity than the usual nano CdS particles. By the addition of sulfur compound into the bio reactor contained the sulfur reducing bacteria, the H{sub 2}S gas concentration can increased to about 1000 times enlarge than the usual condition. Therefore, we can conclude that the enhancement of the H{sub 2}S gas evolved from the bio reactor was successfully achievement, and we don't need to afraid the shortage risk of H{sub 2}S supply. These H{sub 2}S gas concentration can enlarged to 80% by using A type zeorite. Especially, Ca-A type zeorite is considered as the suitable material.

Takahashi, H.; Yokoyama, S.; Baba, Y.; Hayashi, T.; Tohji, K. [Graduate School of Environmental Studies, Tohoku University 6-6-20 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi-ken 980-8579 (Japan)

2008-02-25

292

Hydrogen sulfide prolongs postharvest shelf life of strawberry and plays an antioxidative role in fruits.  

PubMed

Accumulating evidence shows that hydrogen sulfide (H(2)S) plays various physiological roles in plants, such as seed germination, root organogenesis, abiotic stress tolerance, and senescence of cut flowers. However, whether H(2)S participates in the regulation of ripening and senescence in postharvest fruits remains unknown. In the present study, the effect of H(2)S on postharvest shelf life and antioxidant metabolism in strawberry fruits was investigated. Fumigation with H(2)S gas released from the H(2)S donor NaHS prolonged postharvest shelf life of strawberry fruits in a dose-dependent manner. Strawberry fruits fumigated with various concentrations of H(2)S sustained significantly lower rot index, higher fruit firmness, and kept lower respiration intensity and polygalacturonase activities than controls. Further investigation showed that H(2)S treatment maintained higher activities of catalase, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase and lower activities of lipoxygenase relative to untreated controls. H(2)S also reduced malondialdehyde, hydrogen peroxide, and superoxide anion to levels below control fruits during storage. Moreover, H(2)S treatment maintained higher contents of reducing sugars, soluble proteins, free amino acid, and endogenous H(2)S in fruits. We interpret these data as indicating that H(2)S plays an antioxidative role in prolonging postharvest shelf life of strawberry fruits. PMID:22871304

Hu, Lan-Ying; Hu, Shu-Li; Wu, Jun; Li, Yan-Hong; Zheng, Ji-Lian; Wei, Zhao-Jun; Liu, Jian; Wang, Hui-Li; Liu, Yong-Sheng; Zhang, Hua

2012-09-01

293

Adsorption and Reaction of Hydrogen Sulfide on Thin-film Cerium Oxide  

SciTech Connect

The adsorption and reaction of hydrogen sulfide, H{sub 2}S, have been studied on cerium oxide thin films that were vapor deposited on Ru(0 0 0 1). The behavior of the H{sub 2}S was examined as a function of Ce oxidation state. H{sub 2}S weakly chemisorbs on fully oxidized CeO{sub 2} desorbing near 155 K. Hydrogen from the H{sub 2}S reacts with the surface O to desorb as water between 200 K and 450 K. When ca. 20% of the Ce{sup 4+} is reduced to Ce{sup 3+} more H{sub 2}S dissociates to -OH and -SH and water is produced near 580 K. When the ceria is ca. 70% reduced, water formation is suppressed and H{sub 2} desorbs near 580 K. S 2p photoelectron spectroscopy indicates the decomposition of H{sub 2}S into -SH and then -S as the sample is annealed from 100 K to 600 K. O 1s photoemission indicated the presence of H{sub 2}O and -OH.

Mullins, David R [ORNL; McDonald, Tom S [ORNL

2007-01-01

294

Protein kinase g i? oxidation paradoxically underlies blood pressure lowering by the reductant hydrogen sulfide.  

PubMed

Dysregulated blood pressure control leading to hypertension is prevalent and is a risk factor for several common diseases. Fully understanding blood pressure regulation offers the possibility of developing rationale therapies to alleviate hypertension and associated disease risks. Although hydrogen sulfide (H2S) is a well-established endogenous vasodilator, the molecular basis of its blood-pressure lowering action is incompletely understood. H2S-dependent vasodilation and blood pressure lowering in vivo was mediated by it catalyzing formation of an activating interprotein disulfide within protein kinase G (PKG) I?. However, this oxidative activation of PKG I? is counterintuitive because H2S is a thiol-reducing molecule that breaks disulfides, and so it is not generally anticipated to induce their formation. This apparent paradox was explained by H2S in the presence of molecular oxygen or hydrogen peroxide rapidly converting to polysulfides, which have oxidant properties that in turn activate PKG by inducing the disulfide. These observations are relevant in vivo because transgenic knockin mice in which the cysteine 42 redox sensor within PKG has been systemically replaced with a redox-dead serine residue are resistant to H2S-induced blood pressure lowering. Thus, a primary mechanism by which the reductant molecule H2S lowers blood pressure is mediated somewhat paradoxically by the oxidative activation of PKG. PMID:25267801

Stubbert, Daniel; Prysyazhna, Oleksandra; Rudyk, Olena; Scotcher, Jenna; Burgoyne, Joseph R; Eaton, Philip

2014-12-01

295

Bile-acid-activated farnesoid X receptor regulates hydrogen sulfide production and hepatic microcirculation  

PubMed Central

AIM: To investigate whether the farnesoid X receptor (FXR) regulates expression of liver cystathionase (CSE), a gene involved in hydrogen sulfide (H2S) generation. METHODS: The regulation of CSE expression in response to FXR ligands was evaluated in HepG2 cells and in wild-type and FXR null mice treated with 6-ethyl chenodeoxycholic acid (6E-CDCA), a synthetic FXR ligand. The analysis demonstrated an FXR responsive element in the 5’-flanking region of the human CSE gene. The function of this site was investigated by luciferase reporter assays, chromatin immunoprecipitation and electrophoretic mobility shift assays. Livers obtained from rats treated with carbon tetrachloride alone, or in combination with 6-ethyl chenodeoxycholic acid, were studied for hydrogen sulphide generation and portal pressure measurement. RESULTS: Liver expression of CSE is regulated by bile acids by means of an FXR-mediated mechanism. Western blotting, qualitative and quantitative polymerase chain reaction, as well as immunohistochemical analysis, showed that expression of CSE in HepG2 cells and in mice is induced by treatment with an FXR ligand. Administration of 6E-CDCA to carbon tetrachloride treated rats protected against the down-regulation of CSE expression, increased H2S generation, reduced portal pressure and attenuated the endothelial dysfunction of isolated and perfused cirrhotic rat livers. CONCLUSION: These results demonstrate that CSE is an FXR-regulated gene and provide a new molecular explanation for the pathophysiology of portal hypertension. PMID:19418582

Renga, Barbara; Mencarelli, Andrea; Migliorati, Marco; Distrutti, Eleonora; Fiorucci, Stefano

2009-01-01

296

Sulfur isotopic evidence of large release of hydrogen sulfide during P-T transition  

NASA Astrophysics Data System (ADS)

The Permo-Triassic mass extinction is the most devastating event in the history of life on Earth and occurred circa 251 Ma ago. The exact cause of extinction remains uncertain. In order to understand the cause of extinction, we studied the sulfur isotopes and redox sensitive elements from the P-T section of Spiti valley of Himalaya, India. In Spiti valley, 1-10 cm of ferruginous band of sediments separates the Permian shale from Triassic limestone. Analyses of redox sensitive elements such as As, Mo, As, Ni, Sb, Th, Mn and Fe show clear evidence of anoxia or euxinia. The total sulfur content of overlying Triassic limestones varies from 0.1 to 0.25% with ?34S values between -17.7 to -6.4 %. The underlying shales contains 0.2 to 0.4 wt% of sulfur with ?34S of sulfate ranging from -16 to -19.8 %. Whereas sulfate content from the boundary are an order of magnitude higher and varies from 1% to 2.5 wt % with ?34S ranging between -13 to -15.4 %. Both above and below the extinction boundary, the ?34S of pyrites are in general lighter than their sulfate counterpart and this most likely results from bacterial reduction of sulfate. The trend is reversed at the boundary where the pyrites are much heavier than sulfate. We believe that this heavy sulfur isotope composition is due to preferential loss of light sulfur isotope during hydrogen sulfide loss to atmosphere. This occurred when chemocline which separates sulfidic deep water from sulfate rich (oxygenated) water abruptly moved upward to the surface. This migration emits copious amounts of H2S to the atmosphere which may be an associated cause for the extinction.

Rai, V. K.; Mane, P.; Shukla, A. D.; Jackson, T. L.; Thiemens, M. H.

2011-12-01

297

Novel Composite Hydrogen-Permeable Membranes for Non-Thermal Plasma Reactors for the Decomposition of Hydrogen Sulfide  

SciTech Connect

The goal of this experimental project is to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H{sub 2}S) in a non-thermal plasma and recover hydrogen (H{sub 2}) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys), although it has yet to be confirmed in this study. A pulsed corona discharge (PCD) reactor has been fabricated and used to dissociate H{sub 2}S into hydrogen and sulfur. A nonthermal plasma cannot be produced in pure H{sub 2}S with our reactor geometry, even at discharge voltages of up to 30 kV, because of the high dielectric strength of pure H{sub 2}S ({approx}2.9 times higher than air). Therefore, H{sub 2}S was diluted in another gas with lower breakdown voltage (or dielectric strength). Breakdown voltages of H{sub 2}S in four balance gases (Ar, He, N{sub 2} and H{sub 2}) have been measured at different H{sub 2}S concentrations and pressures. Breakdown voltages are proportional to the partial pressure of H{sub 2}S and the balance gas. H{sub 2}S conversion and the reaction energy efficiency depend on the balance gas and H{sub 2}S inlet concentrations. With increasing H{sub 2}S concentrations, H{sub 2}S conversion initially increases, reaches a maximum, and then decreases. H{sub 2}S conversion in atomic balance gases, such as Ar and He, is more efficient than that in diatomic balance gases, such as N{sub 2} and H{sub 2}. These observations can be explained by the proposed reaction mechanism of H{sub 2}S dissociation in different balance gases. The results show that nonthermal plasmas are effective for dissociating H{sub 2}S into hydrogen and sulfur.

Morris D. Argyle; John F. Ackerman; Suresh Muknahallipatna; Jerry C. Hamann; Stanislaw Legowski; Guibling Zhao; Ji-Jun Zhang; Sanil John

2005-10-01

298

New spectrophotometric methods for the determinations of hydrogen sulfide present in the samples of lake water, industrial effluents, tender coconut, sugarcane juice and egg.  

PubMed

The new methods are working on the principle that iron(III) is reduced to iron(II) by hydrogen sulfide, catechol and p-toluidine the system 1/hydrogen sulfide the system 2, in acidic medium followed by the reduced iron forming complex with 1,10-phenanthroline with ?(max) 510 nm. The other two methods are based on redox reactions between electrolytically generated manganese(III) sulfate taken in excess and hydrogen sulfide followed by the unreacted oxidant oxidizing diphenylamine ?(max) 570 the system 3/barium diphenylamine sulphonate ?(max) 540 nm, the system 4. The increase/decrease in the color intensity of the dye products of the systems 1 and 2 or 3 and 4 are proportional to the concentration of hydrogen sulfide with its quantification range 0.035-1.40 ?g ml(-1)/0.14-1.40 ?g ml(-1). PMID:22889607

Shyla, B; Nagendrappa, G

2012-10-01

299

New spectrophotometric methods for the determinations of hydrogen sulfide present in the samples of lake water, industrial effluents, tender coconut, sugarcane juice and egg  

NASA Astrophysics Data System (ADS)

The new methods are working on the principle that iron(III) is reduced to iron(II) by hydrogen sulfide, catechol and p-toluidine the system 1/hydrogen sulfide the system 2, in acidic medium followed by the reduced iron forming complex with 1,10-phenanthroline with ?max 510 nm. The other two methods are based on redox reactions between electrolytically generated manganese(III) sulfate taken in excess and hydrogen sulfide followed by the unreacted oxidant oxidizing diphenylamine ?max 570 the system 3/barium diphenylamine sulphonate ?max 540 nm, the system 4. The increase/decrease in the color intensity of the dye products of the systems 1 and 2 or 3 and 4 are proportional to the concentration of hydrogen sulfide with its quantification range 0.035-1.40 ?g ml-1/0.14-1.40 ?g ml-1.

Shyla, B.; Nagendrappa, G.

2012-10-01

300

Variation in trace element content of magnetite crystallized from a fractionating sulfide liquid, Sudbury, Canada: Implications for provenance discrimination  

NASA Astrophysics Data System (ADS)

Laser ablation ICP-MS analysis has been applied to many accessory minerals in order to understand better the process by which the rock formed and for provenance discrimination. We have determined trace element concentrations of Fe-oxides in massive sulfides that form Ni-Cu-PGE deposits at the base of the Sudbury Igneous Complex in Canada. The samples represent the crystallization products of fractionating sulfide liquids and consist of early-forming Fe-rich monosulfide solution (MSS) cumulates and residual Cu-rich intermediate solid solution (ISS). This study shows that Fe-oxide geochemistry is a sensitive petrogenetic indicator for the degree of fractionation of the sulfide liquid and provides an insight into the partitioning of elements between sulfide and Fe-oxide phases. In addition, it is useful in determining the provenance of detrital Fe-oxide. In a sulfide melt, all lithophile elements (Cr, Ti, V, Al, Mn, Sc, Nb, Ga, Ge, Ta, Hf, W and Zr) are compatible into Fe-oxide. The concentrations of these elements are highest in the early-forming Fe-oxide (titanomagnetite) which crystallized with Fe-rich MSS. Upon the continual crystallization of Fe-oxide from the sulfide liquid, the lithophile elements gradually decrease so that late-forming Fe-oxide (magnetite), which crystallized from the residual Cu-rich liquid, is depleted in these elements. This behavior is in contrast with Fe-oxides that crystallized from a fractionating silicate melt, whereby the concentration of incompatible elements, such as Ti, increases rather than decreases. The behavior of the chalcophile elements in magnetite is largely controlled by the crystallization of the sulfide minerals with only Ni, Co, Zn, Mo, Sn and Pb present above detection limit in magnetite. Nickel, Mo and Co are compatible in Fe-rich MSS and thus the co-crystallizing Fe-oxide is depleted in these elements. In contrast, magnetite that crystallized later from the fractionated liquid with Cu-rich ISS is enriched in Ni, Mo and Co because Fe-rich MSS is absent. The concentrations of Sn and Pb, which are incompatible with Fe-rich MSS, are highest in magnetite that formed from the fractionated Cu-rich liquid. At subsolidus temperatures, ilmenite exsolved from titanomagnetite whereas Al-spinel exsolved from the cores of some magnetite, locally redistributing the trace elements. However, during laser ablation ICP-MS analysis of these Fe-oxides both the magnetite and its exsolution products are ablated so that the analysis represents the original magmatic composition of the Fe-oxide that crystallized from the sulfide melt.

Dare, Sarah A. S.; Barnes, Sarah-Jane; Beaudoin, Georges

2012-07-01

301

Suicide Fads: Frequency and Characteristics of Hydrogen Sulfide Suicides in the United States  

PubMed Central

Objective: To assess the frequency of hydrogen sulfide (H2S) suicides and describe the characteristics of victims in the United States (U.S.) since the technique became common in Japan in 2007. Methods: To ascertain the frequency of intentional H2S related deaths in the U.S. prior to the start of the Japanese trend in 2007, we searched the multiple-cause-of-death data from the National Vital Statistics System. To collect as much information about the victims as possible, we sent an email to the National Association of Medical Examiners (NAME) listserv asking for their cooperation in identifying cases of H2S suicide. To identify cases that were not voluntarily reported by medical examiners but were reported by the media, we conducted Google searches using the search terms: “hydrogen sulfide suicide,” “H2S suicide,” “detergent suicide,” “chemical suicide,” and “suicide fad.” We obtained all available autopsy reports and abstracted information, including the site of the incident, the presence of a note warning others about the toxic gas and the demographic characteristics of the victims. We contacted medical examiners who potentially had custody of the cases that were identified through media reports and requested autopsies of these victims. When unable to obtain the autopsies, we gathered information from the media reports. Results: Forty-five deaths from H2S exposure occurred in the U.S. from 1999 to 2007, all unintentional. Responses from the NAME listserv yielded autopsy reports for 11 victims, and Google searches revealed an additional 19 H2S suicides in the U.S. since 2008. Overall (n=30), two cases were identified during 2008, 10 in 2009, and 18 in 2010. The majority of victims were white males, less than 30-years-old, left a warning note, and were found in cars. There were five reports of injuries to first responders, but no secondary fatalities. Conclusion: H2S suicides are increasing in the U.S., and their incidence is probably underestimated by public health officials and physicians. First responders are at risk when assessing these victims due to the severe toxicity of the gas. Emergency providers must be aware of H2S suicides to educate others and care for the rare survivor. PMID:21731786

Reedy, Sarah Jane D.; Schwartz, Michael D.; Morgan, Brent W.

2011-01-01

302

Hydrogen sulfide differentially affects the hepatic vasculature in response to phenylephrine and endothelin 1 during endotoxemia.  

PubMed

Despite being protective in many disease states, hydrogen sulfide (H(2)S) contributes to organ injury in sepsis. Like the other gasotransmitters, nitric oxide and carbon monoxide, H(2)S is a modulator of the microcirculation. Because microcirculatory dysfunction is a main cause of organ injury during sepsis, the present study was designed to test the effect of H(2)S on microvascular dysfunction in isolated perfused livers. In most microcirculatory beds, endotoxin activates the endothelium, resulting in hyporesponsiveness to catecholamines and a derangement in blood flow distribution. We demonstrate that H(2)S treatment attenuates the increase in portal pressure during infusion of the ?1 adrenergic agonist, phenylephrine (PE) (P < 0.01). Hydrogen sulfide almost completely negated the increase in portal pressure in livers isolated from endotoxemic rats. Treatment with an inhibitor of endogenous H(2)S, DL-propargylglycine (PAG), reversed lipopolysaccharide-induced hyporesponsiveness to PE. Because hepatic microcirculatory dysfunction is associated with excessive sinusoidal vasoconstriction and not dilation, we investigated whether H(2)S affects endothelin 1 (ET-1)-induced vasoconstriction in isolated livers. Contrary to PE treatment, H(2)S did not affect the increase in portal pressure during infusion of ET-1, nor did it attenuate the hypersensitization of the liver to ET-1 during endotoxemia. Hepatic resistance in control rats was increased by PAG treatment during ET-1 infusion, but this increase was not exacerbated during endotoxemia. We monitored hepatic O(2) consumption to assess the effect of vascular changes on oxygen consumption following ET-1 treatment. Low-dose ET-1 infusion caused an increase in hepatic O(2)consumption, whereas low-dose ET-1 infusion decreased O(2) consumption in endotoxemic livers. Interestingly, whereas we observed no effect of PAG on the vascular response to ET-1 infusion during endotoxemia, PAG treatment did maintain O(2), suggesting a more complex effect of H(2)S inhibition. In summary, the discrepancies between the hepatic response to PE and ET-1 suggest that H(2)S differentially contributes to microcirculatory dysfunction in the systemic and hepatic microcirculations. We propose that this is due to H(2)S exerting a differential vasoactive function on presinusoidal and sinusoidal sites within the liver. Moreover, our findings suggest that H(2)S may contribute to the progression of sepsis by contributing to microvascular failure. PMID:23143058

Norris, Eric J; Larion, Sebastian; Culberson, Catherine R; Clemens, Mark G

2013-02-01

303

Phosphorylation of BK channels modulates the sensitivity to hydrogen sulfide (H2S)  

PubMed Central

Introduction: Gases, such as nitric oxide (NO), carbon monoxide (CO), or hydrogen sulfide (H2S), termed gasotransmitters, play an increasingly important role in understanding of how electrical signaling of cells is modulated. H2S is well-known to act on various ion channels and receptors. In a previous study we reported that H2S increased calcium-activated potassium (BK) channel activity. Aims: The goal of the present study is to investigate the modulatory effect of BK channel phosphorylation on the action of H2S on the channel as well as to recalculate and determine the H2S concentrations in aqueous sodium hydrogen sulfide (NaHS) solutions. Methods: Single channel recordings of GH3, GH4, and GH4 STREX cells were used to analyze channel open probability, amplitude, and open dwell times. H2S was measured with an anion selective electrode. Results: The concentration of H2S produced from NaHS was recalculated taking pH, temperature salinity of the perfusate, and evaporation of H2S into account. The results indicate that from a concentration of 300 ?M NaHS, only 11–13%, i.e., 34–41 ?M is effective as H2S in solution. GH3, GH4, and GH4 STREX cells respond differently to phosphorylation. BK channel open probability (Po) of all cells lines used was increased by H2S in ATP-containing solutions. PKA prevented the action of H2S on channel Po in GH4 and GH4 STREX, but not in GH3 cells. H2S, high significantly increased Po of all PKG pretreated cells. In the presence of PKC, which lowers channel activity, H2S increased channel Po of GH4 and GH4 STREX, but not those of GH3 cells. H2S increased open dwell times of GH3 cells in the absence of ATP significantly. A significant increase of dwell times with H2S was also observed in the presence of okadaic acid. Conclusions: Our results suggest that phosphorylation by PKG primes the channels for H2S activation and indicate that channel phosphorylation plays an important role in the response to H2S.

Sitdikova, Guzel F.; Fuchs, Roman; Kainz, Verena; Weiger, Thomas M.; Hermann, Anton

2014-01-01

304

Additive for lubricants and hydrocarbon fuels comprising reaction products of olefins, sulfur, hydrogen sulfide and polymeric succinimide compounds  

SciTech Connect

This patent describes a process for making an additive for lubricants comprising co-reacting: (a) an olefin; (b) sulfur; (c) hydrogen sulfide; and (d) a polymeric succinimide selected from the group consisting of the reaction products of polymeric succinic anhydride with one or more reactants selected from the group consisting of: (a) polyethylene amines selected from the group consisting of diethylene triamines, treithylenetetramine, and tetraethylenepentamine; (b) hydroxyl containing amines, and; (c) polyols in conjunction with (a) or (b) selected from the group consisting of pentaerythritol, and trimethylol propane; at a temperature between about 130/sup 0/C and about 200/sup 0/C and a pressure of about 0 psig to about 900 psig, the reactants being reacted in a molar ratio of olefin, polymeric succinimide, and hydrogen sulfide to sulfur of about 3 to about 0.5, about 0.001, to about 0.4, and about 0.5 to about 0.7, respectively.

Horodysky, A.G.; Law, D.A.

1988-11-22

305

Effect of hydrogen sulfide partial pressure, pH, and chloride content on the SSC resistance of martensitic stainless steels and martensitic precipitation hardening stainless steels  

SciTech Connect

Centrifugal compressor applications require the use of martensitic stainless and martensitic precipitation hardening stainless steels at high hydrogen sulfide partial pressures. These materials do not perform well when tested with standard TM0177 test solutions. This paper describes the effect of hydrogen sulfide partial pressure, pH, and chloride content on their SSC resistance and explains their successful field operational experience. Environmental limits are determined for several materials and heat treat conditions.

Vitale, D.D. [Dresser-Rand Turbo Products, Olean, NY (United States)

1999-11-01

306

NOVEL COMPOSITE HYDROGEN-PERMEABLE MEMBRANES FOR NON-THERMAL PLASMA REACTORS FOR THE DECOMPOSITION OF HYDROGEN SULFIDE  

SciTech Connect

The goal of this experimental project is to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H{sub 2}S) in a non-thermal plasma and recover hydrogen (H{sub 2}) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys), although it has yet to be confirmed in this study. Experiments involving methane conversion reactions were conducted with a preliminary pulsed corona discharge reactor design in order to test and improve the reactor and membrane designs using a non-toxic reactant. This report details the direct methane conversion experiments to produce hydrogen, acetylene, and higher hydrocarbons utilizing a co-axial cylinder (CAC) corona discharge reactor, pulsed with a thyratron switch. The reactor was designed to accommodate relatively high flow rates (655 x 10{sup -6} m{sup 3}/s) representing a pilot scale easily converted to commercial scale. Parameters expected to influence methane conversion including pulse frequency, charge voltage, capacitance, residence time, and electrode material were investigated. Conversion, selectivity and energy consumption were measured or estimated. C{sub 2} and C{sub 3} hydrocarbon products were analyzed with a residual gas analyzer (RGA). In order to obtain quantitative results, the complex sample spectra were de-convoluted via a linear least squares method. Methane conversion as high as 51% was achieved. The products are typically 50%-60% acetylene, 20% propane, 10% ethane and ethylene, and 5% propylene. First Law thermodynamic energy efficiencies for the system (electrical and reactor) were estimated to range from 38% to 6%, with the highest efficiencies occurring at short residence time and low power input (low specific energy) where conversion is the lowest (less than 5%). The highest methane conversion of 51% occurred at a residence time of 18.8 s with a flow rate of 39.4 x 10{sup -6} m{sup 3}/s (5 ft{sup 3}/h) and a specific energy of 13,000 J/l using niobium and platinum coated stainless steel tubes as cathodes. Under these conditions, the First Law efficiency for the system was 8%. Under similar reaction conditions, methane conversions were {approx}50% higher with niobium and platinum coated stainless steel cathodes than with a stainless steel cathode.

Morris D. Argyle; John F. Ackerman; Suresh Muknahallipatna; Jerry C. Hamann; Stanislaw Legowski; Ji-Jun Zhang; Guibing Zhao; Robyn J. Alcanzare; Linna Wang; Ovid A. Plumb

2004-07-01

307

Extraction and quantitative analysis of elemental sulfur from sulfide mineral surfaces by high-performance liquid chromatography  

Microsoft Academic Search

A simple method for the quantitative determination of elemental sulfur on oxidized sulfide minerals is described. Extraction of elemental sulfur in perchloroethylene and subsequent analysis with high-performance liquid chromatography were used to ascertain the total elemental sulfur resulting from the oxidation of arsenopyrite, pyrite, marcasite, chalcopyrite, and chalcocite under various conditions. An initial pretreatment to remove any sulfur already present

Molly M. McGuire; Robert J. Hamers

2000-01-01

308

Production of ammonium thiosulfate by the oxidation of hydrogen sulfide over Nb-Fe mixed oxide catalysts  

Microsoft Academic Search

The selective oxidation of hydrogen sulfide in the presence of excess water and ammonia was studied over niobium-iron mixed oxide catalysts. They showed very high conversion of H2S with lower than 2% of SO2 selectivity. The addition of niobium oxide to iron oxide increased H2S conversion until Nb\\/Fe atomic ratio of 1\\/2, then the conversion decreased as the Nb\\/Fe ratio

Dae-Won Park; Bong-Guk Kim; Moon-Il Kim; Il Kim; Hee-Chul Woo

2004-01-01

309

Seasonal Odor, Ammonia, Hydrogen Sulfide, and Carbon Dioxide Concentrations and Emissions from Swine Grower-Finisher Rooms  

Microsoft Academic Search

Seasonal odor and gas (ammonia [NH3], hydrogen sulfide [H2S], and carbon dioxide [CO2]) concentrations and emission rates (OGCERs) from swine facilities are vital for providing accurate source emissions and reducing the uncertainty of setback distances on the basis of emission data. In this study, a repeated measurement experimental method and a split-block statistical model were used to obtain seasonal OGCER

Gang Sun; Huiqing Guo; Jonathan Peterson; Glauber Mariano; Ani Torres; Wellington Jesus; Walter Nakaema; Maria Jorge; Rauda Mariani; Klara Slezakova; Dionísia Castro; Maria Pereira; Simone Morais; Cristina Delerue-Matos; Maria Alvim-Ferraz; Catherine Barton; Charles Zarzecki; Mark Russell; Marjaleena Aatamila; Pia Verkasalo; Maarit Korhonen; Marja Viluksela; Kari Pasanen; Pekka Tiittanen; Aino Nevalainen; Li Rong; Peter Nielsen; Guoqiang Zhang; Yi-Ming Kuo; Juu-En Chang; Kun-Yu Chang; Chih-C. Chao; Yeu-Juin Tuan; Guo-Ping Chang-Chien; Yongping Li; Guohe Huang; Arhontoula Chatzilazarou; Evangelos Katsoyannos; Olga Gortzi; Stavros Lalas; Yiannis Paraskevopoulos; Euthalia Dourtoglou; John Tsaknis; Tarek Abichou; Jeremy Clark; Sze Tan; Jeffery Chanton; Gary Hater; Roger Green; Doug Goldsmith; Morton Barlaz; Nathan Swan; Zhengmin Qian; Hung-Mo Lin; Walter Stewart; Nirav Shah; Linli Kong; Fen Xu; Denjin Zhou; Zhicao Zhu; Qingci He; Shengwen Liang; Weiqing Chen; Chungsying Lu; Hsunling Bai; Fengsheng Su; Wenfa Chen; Jyh Hwang; Hsiu-Hsia Lee; Judith Chow; John Watson; Douglas Lowenthal; Lung-Wen Chen; Nehzat Motallebi

2010-01-01

310

Metal Oxides Remove Hydrogen Sulfide from Landfill Gas Produced from Waste Mixed with Plaster Board under Wet Conditions  

Microsoft Academic Search

Hydrogen sulfide (H2S) is a major odorant in landfills. We have studied H2S production from landfill residual waste with and without sulfur-containing plaster board, including the influence of the water content in the waste. The laboratory experiments were conducted in 30-L polyethylene containers with a controlled water level. We also studied how different materials removed H2S in reactive layers on

Ove Bergersen; Ketil Haarstad; Van Bowersox; Christopher Lehmann; David Grantz; Kathleen Brown; Walid Bouhamra; Denise Lamoureux; John Evans; Petros Koutrakis; James Winebrake; James Corbett; Aaron Falzarano; J. Hawker; Karl Korfmacher; Sai Ketha; Steve Zilora; Serap Erdal; Laurel Berman; Daniel Hryhorczuk; Saeed Abolhasani; H. Frey; Kangwook Kim; William Rasdorf; Phil Lewis; Shih-Hao Pang; Allan Chambers; Melvin Strosher; Tony Wootton; Jan Moncrieff; Philip McCready; Litao Wang; Jiming Hao; Kebin He; Shuxiao Wang; Junhua Li; Qiang Zhang; David Streets; Joshua Fu; Carey Jang; Hideto Takekawa; Satoru Chatani; Stephanie Konopa; James Mulholland; Matthew Realff; Paul Lemieux; Jaehyun Lim; Liya Yu; Yu. Kostetski; Cheolsoo Lim; Jungho Ryu; Jongchoon Kim; Christian Hogrefe; Kevin Civerolo; Winston Hao; Jia-Yeong Ku; Eric Zalewsky; Gopal Sistla; Ram Hashmonay

2008-01-01

311

The Possible Role of Hydrogen Sulfide as an Endogenous Smooth Muscle Relaxant in Synergy with Nitric Oxide  

Microsoft Academic Search

Hydrogen sulfide (H2S), which is well known as a toxic gas, is produced endogenously in mammalian tissues from L-cysteine mainly by two pyridoxal-5?-phosphate-dependent enzymes, cystathionine ?-synthetase and cystathionine ?-lyase. Recently, we showed that cystathionine ?-synthetase in the brain produces H2S, and that H2S facilitates the induction of hippocampal long-term potentiation by enhancing NMDA receptor activity. Here we show that mRNA

Rumiko Hosoki; Norio Matsuki; Hideo Kimura

1997-01-01

312

Thermosensitive transfer of antimicrobial resistances and citrate utilization and cotransfer of hydrogen sulfide production from an Escherichia coli isolate  

Microsoft Academic Search

A hydrogen-sulfide producing, citrate-positive strain of Escherichia coli isolated from urinary tract infection was found to be resistant to chloramphenicol (Cm), tetracycline (Tc), streptomycin (Sm), trimethoprim (Tmp), sulfamethoxazole (Smx), and cotrimoxazole (Tmp\\/Smx). The strain contained 7 plasmids of molecular sizes 120, 35, 5.0, 3.2, 3.0, 2.6, and 2.4 megadaltons (Md), as detected by agarose gel electrophoresis of plasmid DNA. Thermosensitive

N. Harnett; L. Mangan; S. Brown; C. Krishnan

1996-01-01

313

Aircraft-Fuel-Tank Design for Liquid Hydrogen  

NASA Technical Reports Server (NTRS)

Some of the considerations involved in the design of aircraft fuel tanks for liquid hydrogen are discussed herein. Several of the physical properties of metals and thermal insulators in the temperature range from ambient to liquid-hydrogen temperatures are assembled. Calculations based on these properties indicate that it is possible to build a large-size liquid-hydrogen fuel tank which (1) will weigh less then 15 percent of the fuel weight, (2) will have a hydrogen vaporization rate less than 30 percent of the cruise fuel-flow rate, and (3) can be held in a stand-by condition and readied for flight in a short time.

Reynolds, T W

1955-01-01

314

Isolation and characterization of bacteriophages specific to hydrogen-sulfide-producing bacteria.  

PubMed

The objectives of this study were to isolate and characterize bacteriophages specific to hydrogen-sulfide-producing bacteria (SPB) from raw animal materials, and to develop a SPB-specific bacteriophage cocktail for rendering application. Meat, chicken offal, and feather samples collected from local supermarkets and rendering processing plants were used to isolate SPB (n = 142). Bacteriophages (n = 52) specific to SPB were isolated and purified from the above samples using 18 of those isolated SPB strains as hosts. The host ranges of bacteriophages against 5 selected SPB strains (Escherichia coli, Citrobacter freundii, and Hafnia alvei) were determined. Electron microscopy observation of 9 phages selected for the phage cocktail revealed that 6 phages belonged to the family of Siphoviridae and 3 belonged to the Myoviridae family. Restriction enzyme digestion analysis with endonuclease DraI detected 6 distinguished patterns among the 9 phages. Phage treatment prevented the growth of SPB for up to 10 h with multiplicity of infection ratios of 1, 10, 100, and 1000 in tryptic soy broth at 30 °C, and extended the lag phase of SPB growth for 2 h at 22 °C with multiplicities of infection of 10, 100, and 1000. These results suggest that the selected bacteriophage cocktail has a high potential for phage application to control SPB in raw animal materials destined for the rendering process. PMID:23391228

Gong, Chao; Heringa, Spencer; Singh, Randhir; Kim, Jinkyung; Jiang, Xiuping

2013-01-01

315

Comparative Proteomic Analysis of Differentially Expressed Proteins Induced by Hydrogen Sulfide in Spinacia oleracea Leaves  

PubMed Central

Hydrogen sulfide (H2S), as a potential gaseous messenger molecule, has been suggested to play important roles in a wide range of physiological processes in plants. The aim of present study was to investigate which set of proteins is involved in H2S-regulated metabolism or signaling pathways. Spinacia oleracea seedlings were treated with 100 µM NaHS, a donor of H2S. Changes in protein expression profiles were analyzed by 2-D gel electrophoresis coupled with MALDI-TOF MS. Over 1000 protein spots were reproducibly resolved, of which the abundance of 92 spots was changed by at least 2-fold (sixty-five were up-regulated, whereas 27 were down-regulated). These proteins were functionally divided into 9 groups, including energy production and photosynthesis, cell rescue, development and cell defense, substance metabolism, protein synthesis and folding, cellular signal transduction. Further, we found that these proteins were mainly localized in cell wall, plasma membrane, chloroplast, mitochondria, nucleus, peroxisome and cytosol. Our results demonstrate that H2S is involved in various cellular and physiological activities and has a distinct influence on photosynthesis, cell defense and cellular signal transduction in S. oleracea leaves. These findings provide new insights into proteomic responses in plants under physiological levels of H2S. PMID:25181351

Chen, Juan; Liu, Ting-Wu; Hu, Wen-Jun; Simon, Martin; Wang, Wen-Hua; Chen, Juan; Liu, Xiang; Zheng, Hai-Lei

2014-01-01

316

The role of the headspace in hydrogen sulfide removal during microaerobic digestion of sludge.  

PubMed

The role of the headspace (HS) in the microaerobic removal of hydrogen sulfide from biogas produced during sludge digestion was studied. Research was carried out in a pilot reactor with a total volume of 265 L, under mesophilic conditions. Biogas was successfully desulfurized (99%) by introducing pure oxygen (0.46 NL/L(fed)) into the recirculation stream when the HS volume was both 50.0 and 9.5 L. The removal efficacy dropped sharply to ?15% when the HS was reduced to 1.5 L. The system responded quickly to the operational changes imposed: micro-oxygenation stops and variations in supply, as well as HS volume reductions and increases. As the final result, the microaerobic process required a minimum surface into the gas space to occur, which along with the elemental sulfur deposition in this area indicated that the oxidation took place there. Additionally, the pattern of sulfur accumulation suggested that the removal occurred preferentially on certain materials, and pointed to a significant biological contribution. PMID:22949260

Ramos, I; Díaz, I; Fdz-Polanco, M

2012-01-01

317

Penning ionization electron spectroscopy of hydrogen sulfide by metastable helium and neon atoms.  

PubMed

The dynamics of the Penning ionization of hydrogen sulfide molecules by collision with helium and metastable neon atoms, occurring in the thermal energy range, has been studied by analyzing the energy spectra of the emitted electrons obtained in our laboratory in a crossed beam experiment. These spectra are compared with the photoelectron spectra measured by using He(I) and Ne(I) photons under the same experimental conditions. In this way we obtained the negative energy shifts for the formation of H2S(+) ions in the first three accessible electronic states by He*(2(3,1)S1,0) and Ne*((3)P2,0) Penning ionization collisions: the 2b1 (X?(2)B1) fundamental one, the first 5a1 (Ã(2)A1), and the second 2b2 (B?(2)B2) excited states, respectively. The recorded energy shifts indicate that in the case of He* and Ne*-H2S the autoionization dynamics depends on the features of the collision complex and is mainly driven by an effective global attraction that comes from a balance among several non covalent intermolecular interaction components. This suggests that the Penning ionization should take place, in a specific range of intermolecular distances, as we have already observed in the case of Penning ionization of water molecules [Brunetti, B. G.; Candori, P.; Falcinelli, S.; Pirani, F.; Vecchiocattivi, F. J. Chem. Phys. 2013, 139, 164305-1-164305-8]. PMID:24796487

Falcinelli, Stefano; Candori, Pietro; Bettoni, Marta; Pirani, Fernando; Vecchiocattivi, Franco

2014-08-21

318

Case report: Profound neurobehavioral deficits in an oil field worker overcome by hydrogen sulfide  

SciTech Connect

A 24-year-old oil well tester was rendered semiconscious by hydrogen sulfide (H2S). He received oxygen and was hospitalized but released in 30 minutes. The next day, nausea, vomiting, diarrhea, and incontinence of urine and stool led to rehospitalization. These problems and leg shaking, dizziness, sweating, trouble sleeping, and nightmares prevented his return to work. A physical examination, chest x-ray, and pulmonary function tests were normal 39 months after the episode but vibration sense was diminished. Two choice visual reaction times were delayed. Balance was highly abnormal (5 to 6 cm/sec) with eyes closed. Blink reflex latency was slow (R-1 17.5 msec versus normal 14.3 msec). Numbers written on finger tips were not recognized. Verbal and visual recall were impaired but overlearned memory was intact. Cognitive functions measured by Culture Fair, block design, and digit symbol were impaired. Perceptual motor was slow. Scores for confusion, tension-anxiety, depression, and fatigue were elevated and vigor was reduced. Forty-nine months after exposure his reaction time, sway speed, and color vision had not improved. His recall and his cognitive, constructional, and psychomotor speeds had improved but remained abnormal. These deficits are most likely due to H2S. Similar testing of other survivors is recommended.

Kilburn, K.H. (Univ. of Southern California, Los Angeles (United States))

1993-11-01

319

Hydrogen sulfide alleviates lead-induced photosynthetic and ultrastructural changes in oilseed rape.  

PubMed

The role of hydrogen sulfide (H2S) in alleviating lead (Pb) induced stress in oilseed rape (Brassica napus L.) was studied under laboratory conditions. Plants were grown hydroponically in greenhouse conditions under three levels (0, 100, and 400 µM) of Pb and three levels (0, 100 and 200 µM) of H2S donor, sodium hydrosulfide (NaHS). Application of H2S significantly improved the plant growth, root morphology, chlorophyll contents and photosynthetic activity in leaves of B. napus under Pb stress. Moreover, exogenously applied H2S significantly lowered the Pb concentration in shoots and roots of plants under Pb stress. The microscopic examination indicated that application of exogenous H2S enabled a clean mesophyll cell having a well developed chloroplast with thylakoid membranes and starch grains. A number of modifications could be observed in root tip cell i.e. mature mitochondria, long endoplasmic reticulum and golgibodies under combined application of H2S and Pb. On the basis of these findings, it can be concluded that application of exogenous H2S has a protective role on plant growth, net photosynthesis rate and ultrastructural changes in B. napus plants under high Pb exposures. PMID:24580818

Ali, B; Song, W J; Hu, W Z; Luo, X N; Gill, R A; Wang, J; Zhou, W J

2014-04-01

320

Hydrogen Sulfide: An Endogenous Mediator of Resolution of Inflammation and Injury  

PubMed Central

Abstract Significance: Hydrogen sulfide is emerging as an important mediator of many aspects of inflammation, and perhaps most importantly as a factor promoting the resolution of inflammation and repair of injury. Recent Advances: In the gastrointestinal tract, H2S has been shown to promote healing of ulcers and the resolution of mucosal inflammation. On the other hand, suppression of endogenous H2S synthesis impairs mucosal defense and leads to increased granulocyte infiltration. H2S has been exploited in the design of more effective and safe anti-inflammatory drugs. Critical Issues: Enteric bacteria can be a significant source of H2S, which could affect mucosal integrity; indeed, luminal H2S can serve as an alternative to oxygen as a metabolic substrate for mitochondrial respiration in epithelial cells. Enterocytes and colonocytes thereby represent a “metabolic barrier” to the diffusion of bacteria-derived H2S into the subepithelial space. A compromise of this barrier could result in modulation of mucosal function and integrity by bacterial H2S. Future Directions: Improvements in methods for measurement of H2S and development of more selective inhibitors are crucial for gaining a better understanding of the pathophysiological importance of this mediator. Results from animal studies suggest that H2S-releasing agents are promising therapeutic agents for many indications, but these compounds need to be assessed in a clinical setting. Antioxid. Redox Signal. 17, 58–67. PMID:22017247

Ferraz, Jose G.P.; Muscara, Marcelo N.

2012-01-01

321

Hydrogen sulfide, a potential novel drug, attenuates concanavalin A-induced hepatitis  

PubMed Central

Background Hydrogen sulfide (H2S) is known to exert anti-inflammatory properties. Apoptosis and autophagy play important roles in concanavalin A (Con A)-induced acute hepatitis. The purpose of this study was to explore both the effect and mechanism of H2S on Con A-induced acute hepatitis. Methods BALB/c mice were randomized into sham group, Con A-injection group, and 14 ?mol/kg of sodium hydrosulfide (NaHS, an H2S donor) pretreatment group. Results Aspartate aminotransferase, alanine aminotransferase, and pathological damage were significantly ameliorated by NaHS pretreatment. NaHS pretreatment significantly reduced the levels of interleukin-6 and tumor necrosis factor-? compared with those of the Con A group. The expression of Bcl-2, Bax, Beclin-1, and LC3-2, which play important roles in the apoptosis and autophagy pathways, were also clearly affected by NaHS. Furthermore, NaHS affected the p-mTOR and p-AKT. Conclusion H2S attenuates Con A-induced acute hepatitis by inhibiting apoptosis and autophagy, in part, through activation of the PtdIns3K-AKT1 signaling pathway. PMID:25246769

Cheng, Ping; Chen, Kan; Xia, Yujing; Dai, Weiqi; Wang, Fan; Shen, Miao; Wang, Chengfen; Yang, Jing; Zhu, Rong; Zhang, Huawei; Li, Jingjing; Zheng, Yuanyuan; Wang, Junshan; Zhang, Yan; Lu, Jie; Zhou, Yingqun; Guo, Chuanyong

2014-01-01

322

Carbon monoxide, hydrogen sulfide, and nitric oxide as signaling molecules in the gastrointestinal tract.  

PubMed

Carbon monoxide (CO) and hydrogen sulfide (H2S) used to be thought of simply as lethal and (for H2S) smelly gaseous molecules; now they are known to have important signaling functions in the gastrointestinal tract. CO and H2S, which are produced in the gastrointestinal tract by different enzymes, regulate smooth muscle membrane potential and tone, transmit signals from enteric nerves, and can regulate the immune system. The pathways that produce nitric oxide, H2S, and CO interact; each can inhibit and potentiate the level and activity of the other. However, there are significant differences between these molecules, such as in half-lives; CO is more stable and therefore able to have effects distal to the site of production, whereas nitric oxide and H2S are short lived and act only close to sites of production. We review their signaling functions in the luminal gastrointestinal tract and discuss how their pathways interact. We also describe other physiological functions of CO and H2S and how they might be used as therapeutic agents. PMID:24798417

Farrugia, Gianrico; Szurszewski, Joseph H

2014-08-01

323

Ratiometric two-photon fluorescent probes for mitochondrial hydrogen sulfide in living cells.  

PubMed

Hydrogen sulfide (H2S) is an important signaling molecule with diverse biological roles. Various fluorescent probes for H2S with biological application have been developed. However, two-photon ratiometric imaging of mitochondrial H2S is scarce. In this paper, we report two ratiometric two-photon probes, AcHS-1 and AcHS-2, which employ 4-amino-1,8-naphthalimide as the fluorophore and 4-azidobenzyl carbamate as the H2S response site. These probes exhibit high selectivity toward H2S over biothiols and other reactive species, low detection limits of 50-85 nM, low cytotoxicity, and high stability under physiological conditions. Furthermore, through cell imaging with one-photon and two-photon microscopy, MCF-7 cells incubated with two probes show a marked change in emission color from blue to green in response to H2S. Cell images costraining with a mitochondrial dye reveal that AcHS-2 is a mitochondria-specific two-photon probe for H2S. These results show that AcHS-2 may find useful applications in biological research such as tracking mitochondrial H2S in living biological specimens. PMID:25254293

Liu, Xiu-Ling; Du, Xiao-Jiao; Dai, Chun-Guang; Song, Qin-Hua

2014-10-17

324

Optical properties of copper oxide thin films as selective sensing principle for hydrogen sulfide detection  

NASA Astrophysics Data System (ADS)

Semiconducting cuprous (Cu2O) and cupric oxide (CuO) have been subject to intense research efforts, mainly because of the materials' potential for photovoltaic applications and as doping material. In this work, the impact of hydrogen sulfide (H2S) exposure on thin film samples of CuO and Cu2O has been investigated, focusing on alterations in the optical properties. The materials composition was verified using Raman spectroscopy. The samples were exposed to well-defined dosages of H2S and the transmission and reflection characteristics in the expanded UV/Vis regime (350-1100 nm) were recorded. Cu2O films showed an explicit increase in transmissivity for the wavelength region l = 550-900 nm, besides a general decrease in reflectivity of all samples within the considered spectral range. Optical band gaps were determined using Tauc's plotting, revealing a shift in the slope of a2 of CuO after gas exposure. The observed effects can be exploited as sensing effect, which was examined in a thin film total-internal-reflection (TIR) set-up to transiently monitor surface-gas interactions, yielding reproducible changes in response to 20 min exposure to5 ppm H2S.

Kneer, Janosch; Boxberg, Manuel; Wöllenstein, Jürgen

2013-05-01

325

Measurements of atmospheric dimethylsulfide, hydrogen sulfide, and carbon disulfide during GTE/CITE 3  

NASA Technical Reports Server (NTRS)

Measurements of atmospheric dimethylsulfide (DMS), hydrogen sulfide (H2S), and carbon disulfide (CS2) were made over the North and South Atlantic Ocean as part of the Global Tropospheric Experiment/Chemical Instrumentation Test and Evaluation (GTE/CITE 3) project. DMS and CS2 samples were collected and analyzed using an automated gas chromatography/flame photometric detection system with a sampling frequency of 10 min. H2S samples were collected using silver nitrate impregnated filters and analyzed by fluorescence quenching. The DMS data from both hemispheres have a bimodal distribution. Over the North Atlantic this reflects the difference between marine and continental air masses. Over the South Atlantic it may reflect differences in the sea surface source of DMS, corresponding to different air mass source regions. The median boundary layer H2S and CS2 levels were significantly higher in the northern hemisphere than the southern hemisphere, reflecting the higher frequency of samples influenced by pollutant and/or coastal emissions. Composite vertical profiles of DMS and H2S are similar to each other, are consistent with a sea surface source. Vertical profiles of CS2 have maxima in the free troposphere, implicating a continental source. The low levels of H2S and CS2 found in the southern hemisphere constrain the role of these compounds in global budgets to significantly less than previously estimated.

Cooper, David J.; Saltzman, Eric S.

1993-01-01

326

Thionine as an indicator for use as a hydrogen sulfide optode  

NASA Astrophysics Data System (ADS)

The amount of dissolved hydrogen sulfide is an important parameter in many environmental applications. Conventional methods for H2S detection depend on iodometric titration or spectroscopic measurements. Unfortunately these methods are not applicable for direct measurements in natural systems. A recently described method for the on-line detection of H2S is based on quenching of fluorescence of thioneine. The reaction between H2S and thioneine was described as reversible photo-reduction. This reaction was tested in order to design an optical microsensor for the measurement of H2S in sediments and other biological systems. We immobilized thioneine in several matrices and investigated these materials with respect to response time, mechanical stability, the influence of the excitation light and the reversibility. The sensing materials were deposited on the tip of optical fibers. The measuring system for the excitation and detection of the fluorescence consisted of a yellow light emitting diode, a fiber-optic coupler and a photomultiplier. The excitation light was intensity modulated to enable measurements in ambient light. Our results indicate that the thioneine based reaction scheme for H2S detection is not very suitable for use in a H2S optode due to lack of reversibility, long response times, and the need for regeneration of the sensor chemistry.

Kohls, Oliver; Klimant, Ingo; Holst, Gerhard A.; Kuehl, Michael

1996-12-01

327

The effects of acute hydrogen sulfide poisoning on cytochrome P450 isoforms activity in rats.  

PubMed

Hydrogen sulfide (H2S) is the second leading cause of toxin related death (after carbon monoxide) in the workplace. H2S is absorbed by the upper respiratory tract mucosa, and it causes histotoxic hypoxemia and respiratory depression. Cocktail method was used to evaluate the influences of acute H2S poisoning on the activities of cytochrome P450 isoforms CYP2B6, CYP2D6, CYP3A4, CYP1A2, CYP2C19, and CYP2C9, which were reflected by the changes of pharmacokinetic parameters of six specific probe drugs, bupropion, metoprolol, midazolam, phenacetin, omeprazole, and tolbutamide, respectively. The experimental rats were randomly divided into two groups, control group and acute H2S poisoning group (inhaling 300?ppm for 2?h). The mixture of six probes was given to rats by oral administration and the blood samples were obtained at a series of time points through the caudal vein. The concentrations of probe drugs in rat plasma were measured by LC-MS. The results for acute H2S poisoning and control groups were as follows: there was a statistically significant difference in the AUC and C max for bupropion, metoprolol, phenacetin, and tolbutamide, while there was no statistical pharmacokinetic difference for midazolam and omeprazole. Acute H2S poisoning could inhibit the activity of CYP2B6, CYP2D6, CYP1A2, and CYP2C9 in rats. PMID:24790991

Wang, Xianqin; Chen, Mengchun; Chen, Xinxin; Ma, Jianshe; Wen, Congcong; Pan, Jianchun; Hu, Lufeng; Lin, Guanyang

2014-01-01

328

Hydrogen sulfide-linked sulfhydration of NF-?B mediates its anti-apoptotic actions  

PubMed Central

Summary Nuclear factor ?B (NF-?B) is an anti-apoptotic transcription factor. We show that the anti-apoptotic actions of NF-?B are mediated by hydrogen sulfide (H2S) synthesized by cystathionine gamma-lyase (CSE). TNF? treatment triples H2S generation by stimulating binding of SP1 to the CSE promoter. H2S generated by CSE stimulates DNA binding and gene activation of NF-?B, processes that are abolished in CSE deleted mice. As CSE deletion leads to decreased glutathione levels, resultant oxidative stress may contribute to alterations in CSE mutant mice. H2S acts by sulfhydrating the p65 subunit of NF-?B at cysteine-38, which promotes its binding to the co-activator ribosomal protein S3 (RPS3). Sulfhydration of p65 predominates early following TNF? treatment, then declines and is succeeded by a reciprocal enhancement of p65 nitrosylation. Anti-apoptotic influences of NF-?B, which are markedly diminished in CSE mutant mice. Thus, sulfhydration of NF-?B appears to be a physiologic determinant of its anti-apoptotic transcriptional activity. PMID:22244329

Sen, Nilkantha; Paul, Bindu D.; Gadalla, Moataz M.; Mustafa, Asif K.; Sen, Tanusree; Xu, Risheng; Kim, Seyun; Snyder, Solomon H.

2011-01-01

329

Hydrogen sulfide modulates the release of nitric oxide and VEGF in human keratinocytes.  

PubMed

Hydrogen sulfide (H(2)S) is a novel signaling molecule with both pro- or anti-inflammatory effect. The present study aimed to: (i) characterize the in vitro effects of H(2)S on human keratinocyte's proliferation and death; (ii) investigate the ability of H(2)S to modulate VEGF and NO production; (iii) examine the intracellular signaling pathways involved in VEGF and NO modulatory effect. We found that exogenous application of H(2)S (NaHS and GYY4137 as H(2)S donors) significantly enhances NO through increase of iNOS, in a manner Akt-dependent. The increment in NO down-regulates ERK1/2 activation thereby resulting in the decrease of VEGF release. We suggest that H(2)S-releasing agents may be promising therapeutics for chronic inflammatory disorders of the skin, i.e. psoriasis, in which NO increases as well as anti-VEGF treatments have been suggested to be novel effective approaches. PMID:22842066

Merighi, Stefania; Gessi, Stefania; Varani, Katia; Fazzi, Debora; Borea, Pier Andrea

2012-11-01

330

C. elegans aging is modulated by hydrogen sulfide and the sulfhydrylase/cysteine synthase cysl-2.  

PubMed

Exogenous hydrogen sulfide (H2S) administration and endogenous H2S metabolism were explored in the nematode C. elegans. Chronic treatment with a slow-releasing H2S donor, GYY4137, extended median survival by 17-23% and increased tolerance towards oxidative and endoplasmic reticulum (ER) stress. Also, cysl-2, a sulfhydrylase/cysteine synthase in C. elegans, was transcriptionally upregulated by GYY4137 treatment and the deletion of cysl-2 resulted in a significant reduction in lifespan which was partially recovered by the supplementation of GYY4137. Likewise, a mammalian cell culture system, GYY4137 was able to protect bovine aortic endothelial cells (BAECs) from oxidative stress and (H2O2)-induced cell death. Taken together, this provides further support that H2S exerts a protective function which is consistent with the longevity dividend theory. Overall, this study underlines the therapeutic potential of a slow-releasing H2S donor as regulators of the aging and cellular stress pathways. PMID:24260346

Qabazard, Bedoor; Ahmed, Samanza; Li, Ling; Arlt, Volker M; Moore, Philip K; Stürzenbaum, Stephen R

2013-01-01

331

A novel hydrogen sulfide donor causes stomatal opening and reduces nitric oxide accumulation.  

PubMed

Effects of hydrogen sulfide (H(2)S) on plant physiology have been previously studied, but such studies have relied on the use of NaSH as a method for supplying H(2)S to tissues. Now new compounds which give a less severe H(2)S shock and a more prolonged exposure to H(2)S have been developed. Here the effects of one such compound, GYY4137, has been investigated to determine its effects on stomatal closure in Arabidopsis thaliana. It was found that both NaSH and GYY4137 caused stomatal opening in the light and prevented stomatal closure in the dark. Nitric oxide (NO) has been well established as a mediator of stomatal movements and here it was found that both NaSH and GYY4137 reduced the accumulation of NO in guard cells, perhaps suggesting a mode of action for H(2)S in this system. GYY4137, and future related compounds, will be important tools to unravel the effects of plant exposure to H(2)S and to determine how H(2)S may fit into plant cell signalling pathways. PMID:20970349

Lisjak, M; Srivastava, N; Teklic, T; Civale, L; Lewandowski, K; Wilson, I; Wood, M E; Whiteman, M; Hancock, J T

2010-12-01

332

Hydrogen Sulfide Ameliorates Ischemia/Reperfusion-Induced Hepatitis by Inhibiting Apoptosis and Autophagy Pathways  

PubMed Central

Background. Hepatic ischemia/reperfusion (I/R) injury is an important clinical problem, and its consequences can seriously threaten human health. Apoptosis and autophagy have been shown to contribute to cell death in hepatic I/R injury. Hydrogen sulfide (H2S) is the third most common endogenously produced gaseous signaling molecule and is known to exert a protective effect against hepatic I/R injury. In this study, the purpose is to explore both the effect and mechanism of H2S on hepatic I/R injury. Methods. Balb/c mice were randomized into Sham, I/R, or two doses (14??mol/kg and 28??mol/kg) of sodium hydrosulfide (NaHS, an H2S donor) preconditioning groups. Results. NaHS significantly reduced the levels of TNF-? and IL-6 at 12?h and 24?h after injection compared with ischemia/reperfusion challenge alone. The expression of Bcl-2, Bax, Beclin-1, and LC3, which play important roles in the regulation of the apoptosis and autophagy pathways, was also clearly affected by NaHS. Furthermore, NaHS affected the p-JNK1, p-ERK1, and p-p38. Conclusion. Our results indicate that H2S attenuates hepatic I/R injury, at least in part, by regulating apoptosis through inhibiting JNK1 signaling. The autophagy agonist rapamycin potentiated this hepatoprotective effect by reversing the inhibition of autophagy by H2S. PMID:24966472

Cheng, Ping; Wang, Fan; Chen, Kan; Shen, Miao; Dai, Weiqi; Xu, Ling; Zhang, Yan; Wang, Chengfen; Li, Jingjing; Yang, Jing; Zhu, Rong; Zhang, Huawei; Zheng, Yuanyuan; Lu, Jie; Zhou, Yingqun; Guo, Chuanyong

2014-01-01

333

Hydrogen sulfide alleviates hypoxia-induced root tip death in Pisum sativum.  

PubMed

Flooding of soils often results in hypoxic conditions surrounding plant roots, which is a harmful abiotic stress to crops. Hydrogen sulfide (H2S) is a highly diffusible, gaseous molecule that modulates cell signaling and is involved in hypoxia signaling in animal cells. However, there have been no previous studies of H2S in plant cells in response to hypoxia. The effects of H2S on hypoxia-induced root tip death were studied in pea (Pisum sativum) via analysis of endogenous H2S and reactive oxygen species (ROS) levels. The activities of key enzymes involved in antioxidative and H2S metabolic pathways were determined using spectrophotometric assays. Ethylene was measured by gas chromatography. We found that exogenous H2S pretreatment dramatically alleviated hypoxia-induced root tip death by protecting root tip cell membranes from ROS damage induced by hypoxia and by stimulating a quiescence strategy through inhibiting ethylene production. Conversely, root tip death induced by hypoxia was strongly enhanced by inhibition of the key enzymes responsible for endogenous H2S biosynthesis. Our results demonstrated that exogenous H2S pretreatment significantly alleviates hypoxia-induced root tip death in pea seedlings and, therefore, enhances the tolerance of the plant to hypoxic stress. PMID:23800663

Cheng, Wei; Zhang, Liang; Jiao, Chengjin; Su, Miao; Yang, Tao; Zhou, Lina; Peng, Renyi; Wang, Ranran; Wang, Chongying

2013-09-01

334

Hydrogen Sulfide Alleviates Diabetic Nephropathy in a Streptozotocin-induced Diabetic Rat Model.  

PubMed

Accumulating evidence has demonstrated that hydrogen sulfide (H2S) plays critical roles in the pathogenesis of chronic kidney diseases. This study was designed to investigate whether H2S has protective effects against diabetic nephropathy. Diabetic rats were induced by intraperitoneal injection of streptozotocin and administrated with H2S donor NaHS for 12 weeks. Rat glomerular mesangial cells were pretreated with NaHS or MAPK inhibitors (U0126, SP600125, and SB203580) prior to high glucose exposure, and cell proliferation was determined. Our findings suggest that H2S can improve renal function and attenuate glomerular basement membrane thickening, mesangial matrix deposition, and renal interstitial fibrosis in diabetic rats. H2S was found to reduce high glucose-induced oxidative stress by activating the Nrf2 antioxidant pathway and to exert anti-inflammatory effects by inhibiting NF-?B signaling. In addition, H2S reduced high glucose-induced mesangial cell proliferation by blockade of MAPK signaling pathways. Moreover, H2S was also found to inhibit the renin-angiotensin system in diabetic kidney. In conclusion, our study demonstrates that H2S alleviates the development of diabetic nephropathy by attenuating oxidative stress and inflammation, reducing mesangial cell proliferation, and inhibiting renin-angiotensin system activity. PMID:25164822

Zhou, Xiang; Feng, Yu; Zhan, Zhoubing; Chen, Jianchang

2014-10-17

335

Role of hydrogen sulfide in the formalin-induced orofacial pain in rats.  

PubMed

Hydrogen sulfide (H2S) is a gasotransmitter synthesized in peripheral tissues by the enzyme cystathionine gamma-lyase (CSE). This gas has been documented to be involved in a wide variety of processes including inflammation and nociception. The aim of the present study was to investigate the role of the peripheral H2S pathway in nociceptive response to the orofacial formalin experimental model of pain. Orofacial pain was induced by subcutaneous injection of formalin (1.5%, 50 µl) into the upper lip of rats, and the time spent rubbing the face was measured at 3-min intervals for 45 min. Formalin induced a marked biphasic pain (first phase: 0-3 min; second phase: 15-33 min). Pretreatment with H2S donor (Na2S; 90 µmol/kg), CSE inhibitor (propargylglycine; 26.5 and 88.4 µmol/kg), or a preferential blocker of T-type Ca(2+) channels (mibefradil; 0.28 and 2.81 µmol/kg) attenuated the second phase of face rubbing when injected locally as well as systemically. Pretreatment with a selective blocker of K(+)ATP channels (glybenclamide; 2.81 µmol/kg) suppressed the Na2S-mediated attenuation of the formalin-induced pain second phase. Taken together these results suggest that endogenously produced H2S plays a pronociceptive role probably via T-type Ca(2+) channels, whereas exogenous H2S exerts antinociceptive effects mediated by K(+)ATP channels. PMID:24876060

Donatti, Alberto F; Araujo, Rebeca M; Soriano, Renato N; Azevedo, Leopoldo U; Leite-Panissi, Christie A; Branco, Luiz G S

2014-09-01

336

Hydrogen sulfide improves left ventricular function in smoking rats via regulation of apoptosis and autophagy.  

PubMed

The present study was designed to investigate the protective effects of hydrogen sulfide (H2S) against cigarette smoking-induced left ventricular dysfunction in rats. Left ventricular structure and function were assessed using two-dimensional echocardiography. Cardiomyocyte apoptosis was determined by Annexin V/PI and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining. Cardiac autophagy was evaluated by detection of autophagy-related protein expression and observation of autophagosomes. Our results indicated that administration of NaHS (a donor of H2S) could protect against smoking-induced left ventricular systolic dysfunction. H2S was found to exert anti-apoptotic effects in the myocardium of smoking rats by inhibiting JNK and P38 mitogen-activated protein kinases pathways and activating PI3K/Akt signaling. Moreover, H2S could also reduce smoking-induced autophagic cell death via regulation of AMPK/mTOR signaling pathway. In conclusion, our study demonstrates that H2S can improve left ventricular systolic function in smoking rats via regulation of apoptosis and autophagy. PMID:24658667

Zhou, Xiang; An, Guoyin; Chen, Jianchang

2014-06-01

337

Comparative proteomic analysis of differentially expressed proteins induced by hydrogen sulfide in Spinacia oleracea leaves.  

PubMed

Hydrogen sulfide (H2S), as a potential gaseous messenger molecule, has been suggested to play important roles in a wide range of physiological processes in plants. The aim of present study was to investigate which set of proteins is involved in H2S-regulated metabolism or signaling pathways. Spinacia oleracea seedlings were treated with 100 µM NaHS, a donor of H2S. Changes in protein expression profiles were analyzed by 2-D gel electrophoresis coupled with MALDI-TOF MS. Over 1000 protein spots were reproducibly resolved, of which the abundance of 92 spots was changed by at least 2-fold (sixty-five were up-regulated, whereas 27 were down-regulated). These proteins were functionally divided into 9 groups, including energy production and photosynthesis, cell rescue, development and cell defense, substance metabolism, protein synthesis and folding, cellular signal transduction. Further, we found that these proteins were mainly localized in cell wall, plasma membrane, chloroplast, mitochondria, nucleus, peroxisome and cytosol. Our results demonstrate that H2S is involved in various cellular and physiological activities and has a distinct influence on photosynthesis, cell defense and cellular signal transduction in S. oleracea leaves. These findings provide new insights into proteomic responses in plants under physiological levels of H2S. PMID:25181351

Chen, Juan; Liu, Ting-Wu; Hu, Wen-Jun; Simon, Martin; Wang, Wen-Hua; Chen, Juan; Liu, Xiang; Zheng, Hai-Lei

2014-01-01

338

Measurement of low concentration and nano-quantity hydrogen sulfide in sera using unfunctionalized carbon nanotubes  

NASA Astrophysics Data System (ADS)

Hydrogen sulfide (H2S) is produced in small amounts by certain cells in the mammalian body and has a number of biological functions. H2S gas naturally produced by the body is not simply a toxic gas; it could be a vascular dilator and play a physiological role in regulating cardiovascular functions. In order to know the effects of H2S, it is necessary to accurately know its concentrations in the body. Conventional measurement methods have their limitations concerning the small amount and low concentration of H2S in the body. A new paradigm of using carbon nanotubes in H2S measurement expresses its potential. However, the influence of proteins in the mammalian body must be studied in the measurement of H2S by carbon nanotubes. In this paper, we demonstrate a successful measurement of low concentration (20 µM) and nano-quantity (0.5 µg) H2S in the serum by using carbon nanotubes and further with the fluorescence of confocal laser scanning microscopy and the luminescence of Raman microscopy. Statistical analysis of the experimental data shows that the relationship between concentrations and intensities is linear, which thus makes the carbon nanotube sensor highly promising for the measurement of H2S in sera.

Wu, X. C.; Zhang, W. J.; Sammynaiken, R.; Meng, Q. H.; Wu, D. Q.; Yang, Q.; Yang, W.; Zhang, Edwin M.; Wang, R.

2009-10-01

339

Role of Cystathionine ?-Lyase/Hydrogen Sulfide Pathway in Cardiovascular Disease: A Novel Therapeutic Strategy?  

PubMed Central

Abstract Significance: Hydrogen sulfide (H2S) has traditionally been considered a toxic environmental pollutant. In the late 1990s, the presumed solely harmful role of H2S has been challenged because H2S may also be involved in the maintenance and preservation of cardiovascular homeostasis. Recent Advances: The production of endogenous H2S has been attributed to three key enzymes, cystathionine ?-lyase (CSE), cystathionine ?-synthase, and 3-mercaptopyruvate sulfurtransferase. The recognition of H2S as the third gaseous signaling molecule has stimulated research on a multitude of pathophysiologic events in the cardiovascular system. In particular, important roles in cardiovascular disorder processes are ascribed to the CSE/H2S pathway, such as atherosclerosis, myocardial infarction, hypertension, and shock. Critical Issues: Many biological activities and molecular mechanisms of H2S in the cardiovascular system have been demonstrated in studies using different tools, such as the genetic overexpression of CSE, the direct administration of H2S donors, or the use of H2S-releasing pro-drugs. Unfortunately, the role of the CSE/H2S pathway in cardiovascular disease remains controversial in numerous areas, and many questions regarding the gaseous molecule still remain unanswered. Future Directions: Advances in basic research indicate that the CSE/H2S pathway may provide potential therapeutic targets for treating cardiovascular disorders. But the molecular targets of H2S still need to be identified. Antioxid. Redox Signal. 17, 106–118. PMID:22017202

Pan, Li Long; Liu, Xin Hua; Gong, Qi Hai; Yang, He Bei

2012-01-01

340

A Practical Look at the Chemistry and Biology of Hydrogen Sulfide  

PubMed Central

Abstract Significance: Hydrogen sulfide (H2S) is garnering increasing interest as a biologically relevant signaling molecule. The effects of H2S have now been observed in virtually every organ system and numerous physiological processes. Recent Advances: These studies have not only opened a new field of “gasotransmitter” biology, they have also led to the development of synthetic H2S “donating” compounds with the potential to be parlayed into a variety of therapeutic applications. Critical Issues: Often lost in the exuberance of this new field is a critical examination or understanding of practical aspects of H2S chemistry and biology. This is especially notable in the areas of handling and measuring H2S, evaluating biosynthetic and metabolic pathways, and separating physiological from pharmacological responses. Future Directions: This brief review describes some of the pitfalls in H2S chemistry and biology that can lead or have already led to misleading or erroneous conclusions. The intent is to allow individuals entering or already in this burgeoning field to critically analyze the literature and to assist them in the design of future experiments. Antioxid. Redox Signal. 17, 32–44. PMID:22074253

2012-01-01

341

Hydrogen sulfide cytoprotective signaling is endothelial nitric oxide synthase-nitric oxide dependent  

PubMed Central

Previous studies have demonstrated that hydrogen sulfide (H2S) protects against multiple cardiovascular disease states in a similar manner as nitric oxide (NO). H2S therapy also has been shown to augment NO bioavailability and signaling. The purpose of this study was to investigate the impact of H2S deficiency on endothelial NO synthase (eNOS) function, NO production, and ischemia/reperfusion (I/R) injury. We found that mice lacking the H2S-producing enzyme cystathionine ?-lyase (CSE) exhibit elevated oxidative stress, dysfunctional eNOS, diminished NO levels, and exacerbated myocardial and hepatic I/R injury. In CSE KO mice, acute H2S therapy restored eNOS function and NO bioavailability and attenuated I/R injury. In addition, we found that H2S therapy fails to protect against I/R in eNOS phosphomutant mice (S1179A). Our results suggest that H2S-mediated cytoprotective signaling in the setting of I/R injury is dependent in large part on eNOS activation and NO generation. PMID:24516168

King, Adrienne L.; Polhemus, David J.; Bhushan, Shashi; Otsuka, Hiroyuki; Kondo, Kazuhisa; Nicholson, Chad K.; Bradley, Jessica M.; Islam, Kazi N.; Calvert, John W.; Tao, Ya-Xiong; Dugas, Tammy R.; Kelley, Eric E.; Elrod, John W.; Huang, Paul L.; Wang, Rui; Lefer, David J.

2014-01-01

342

Toward new instruments for measurement of low concentration hydrogen sulfide in small-quantity aqueous solutions  

NASA Astrophysics Data System (ADS)

Endogenously generated hydrogen sulfide (H2S) has been found to play some important physiological roles in the nervous and cardiovascular systems, such as a neuromodulator and a vasorelaxant. These roles are in contrast to our common perception that H2S is toxic. However, whether H2S plays a positive or negative role is dependent on the H2S concentration levels in mammals. This further puts a high demand on the accurate measurement of H2S in mammals with a further desire to be real time, continuous and in vivo. Existing methods for H2S measurement require a large number of tissue samples with complex procedures, and these methods are extremely invasive. The development of new in vivo and real-time methods for measuring H2S is, however, a great challenge. In the present study, we proposed and examined five potential H2S measurement methods: (1) atomic force microscopy with coating materials, (2) Raman spectroscopy on the H2S solutions, (3) gas chromatography/mass spectroscopy (with the static headspace technique) on the H2S solutions, (4) mass spectroscopy on unfunctionalized carbon nanotubes treated with the H2S solutions and (5) Raman spectroscopy on unfunctionalized carbon nanotubes treated with the H2S solutions. Our study concluded that method (5) is the most promising one for detecting low concentration H2S in small-quantity aqueous solutions in terms of measurement resolution and non-invasiveness, but the method is not very robust.

Wu, Xiao Chu; Qing Wu, Dong; Sammynaiken, R.; Yang, Wei; Wang, Rui; Zhang, W. J.

2008-11-01

343

Inhaled Hydrogen Sulfide Prevents Neurodegeneration and Movement Disorder in a Mouse Model of Parkinson's Disease  

PubMed Central

Abstract Parkinson's disease is one of the major neurodegenerative disorders. Neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) can cause Parkinson's disease–like symptoms and biochemical changes in humans and animals. Hydrogen sulfide (H2S) has been shown to protect neurons. The goal of this study was to examine the effects of inhaled H2S in a mouse model of Parkinson's disease induced by MPTP. Male C57BL/6J mice received MPTP at 80?mg/kg and breathed air with or without 40 ppm H2S for 8?h/day for 7 days. Administration of MPTP induced movement disorder and decreased tyrosine hydroxylase (TH)-containing neurons in the substantia nigra and striatum in mice that breathed air. Inhalation of H2S prevented the MPTP-induced movement disorder and the degeneration of TH-containing neurons. Inhaled H2S also prevented apoptosis of the TH-containing neurons and gliosis in nigrostriatal region after administration of MPTP. The neuroprotective effect of inhaled H2S after MPTP administration was associated with upregulation of genes encoding antioxidant proteins, including heme oxygenase-1 and glutamate-cysteine ligase. These observations suggest that inhaled H2S prevents neurodegeneration in a mouse model of Parkinson's disease induced by MPTP, potentially via upregulation of antioxidant defense mechanisms and inhibition of inflammation and apoptosis in the brain. Antioxid. Redox Signal. 15, 343–352. PMID:21050138

Kida, Kotaro; Yamada, Marina; Tokuda, Kentaro; Marutani, Eizo; Kakinohana, Manabu; Kaneki, Masao

2011-01-01

344

Highly sensitive hydrogen sulfide (H?S) gas sensors from viral-templated nanocrystalline gold nanowires.  

PubMed

A facile, site-specific viral-templated assembly method was used to fabricate sensitive hydrogen sulfide (H2S) gas sensors at room temperature. A gold-binding M13 bacteriophage served to organize gold nanoparticles into linear arrays which were used as seeds for subsequent nanowire formation through electroless deposition. Nanowire widths and densities within the sensors were modified by electroless deposition time and phage concentration, respectively, to tune device resistance. Chemiresistive H2S gas sensors with superior room temperature sensing performance were produced with sensitivity of 654%/ppm(v), theoretical lowest detection limit of 2 ppb(v), and 70% recovery within 9 min for 0.025 ppm(v). The role of the viral template and associated gold-binding peptide was elucidated by removing organics using a short O? plasma treatment followed by an ethanol dip. The template and gold-binding peptide were crucial to electrical and sensor performance. Without surface organics, the resistance fell by several orders of magnitude, the sensitivity dropped by more than a factor of 100 to 6%/ppm(v), the lower limit of detection increased, and no recovery was detected with dry air flow. Viral templates provide a novel, alternative fabrication route for highly sensitive, nanostructured H2S gas sensors. PMID:24598078

Moon, Chung Hee; Zhang, Miluo; Myung, Nosang V; Haberer, Elaine D

2014-04-01

345

Hydrogen Sulfide Improves Drought Tolerance in Arabidopsis thaliana by MicroRNA Expressions  

PubMed Central

Hydrogen sulfide (H2S) is a gasotransmitter and plays an important role in many physiological processes in mammals. Studies of its functions in plants are attracting ever growing interest, for example, its ability to enhance drought resistance in Arabidopsis. A general role of microRNAs (miRNAs) in plant adaptive responses to drought stress has thereby increased our interest to delve into the possible interplay between H2S and miRNAs. Our results showed that treating wild type (WT) Arabidopsis seedlings with polyethylene glycol 8000 (PEG8000) to simulate drought stress caused an increase in production rate of endogenous H2S; and a significant transcriptional reformation of relevant miRNAs, which were also triggered by exogenous H2S in WT. When lcd mutants (with lower H2S production rate than WT) were treated with PEG8000, they showed lower levels of miRNA expression changes than WT. In addition, we detected significant changes in target gene expression of those miRNAs and the corresponding phenotypes in lcd, including less roots, retardation of leaf growth and development and greater superoxide dismutase (SOD) activity under drought stress. We thereby conclude that H2S can improve drought resistance through regulating drought associated miRNAs in Arabidopsis. PMID:24194857

Yuan, Huihong; Liu, Zhiqiang; Jin, Zhuping; Zhang, Liping; Pei, Yanxi

2013-01-01

346

Cellular mechanism underlying hydrogen sulfide induced mouse tracheal smooth muscle relaxation: Role of BKCa.  

PubMed

Recent studies have suggested that hydrogen sulfide (H2S), an important endogenous signaling gaseous molecule, participates in relaxation of smooth muscle. Nevertheless, the mechanism of this relaxation effect on respiratory system is still unclear. The present study aims to investigate the physiological function as well as cellular mechanism of H2S in tracheal smooth muscle. Application of the H2S donor, sodium hydrosulphide (NaHS) and the precursor of H2S, l-cysteine (l-Cys) induced mouse tracheal smooth muscle (TSM) relaxation in an epithelium-independent manner. The relaxation of TSM induced by NaHS was abrogated by iberiotoxin (IbTX), the large conductance calcium activated potassium channel (BKCa) blocker. In primary cultured mouse TSM cells, NaHS remarkably increased potassium outward currents in whole-cell patch clamp, hyperpolarized TSM cells and inhibited the calcium influx. All of these effects were significantly blocked by IbTX. Consistent with the results in vitro, administration of NaHS in vivo also reduced airway hyperresponsiveness in Ovalbumin (OVA)-challenged asthmatic mice. Our present study indicates that NaHS can induce mouse TSM relaxation by activating BKCa. These observations reveal the physiological function of H2S in airway, which provides a promising pharmacological target for the treatment of asthma and other respiratory diseases associated with over-contraction of TSM. PMID:25034810

Huang, Jiehong; Luo, Yu-Li; Hao, Yuan; Zhang, Yi-Lin; Chen, Peng-Xiao; Xu, Jia-Wen; Chen, Min-Hui; Luo, Yong-Feng; Zhong, Nan-Shan; Xu, Jun; Zhou, Wen-Liang

2014-10-15

347

The Effects of Acute Hydrogen Sulfide Poisoning on Cytochrome P450 Isoforms Activity in Rats  

PubMed Central

Hydrogen sulfide (H2S) is the second leading cause of toxin related death (after carbon monoxide) in the workplace. H2S is absorbed by the upper respiratory tract mucosa, and it causes histotoxic hypoxemia and respiratory depression. Cocktail method was used to evaluate the influences of acute H2S poisoning on the activities of cytochrome P450 isoforms CYP2B6, CYP2D6, CYP3A4, CYP1A2, CYP2C19, and CYP2C9, which were reflected by the changes of pharmacokinetic parameters of six specific probe drugs, bupropion, metoprolol, midazolam, phenacetin, omeprazole, and tolbutamide, respectively. The experimental rats were randomly divided into two groups, control group and acute H2S poisoning group (inhaling 300?ppm for 2?h). The mixture of six probes was given to rats by oral administration and the blood samples were obtained at a series of time points through the caudal vein. The concentrations of probe drugs in rat plasma were measured by LC-MS. The results for acute H2S poisoning and control groups were as follows: there was a statistically significant difference in the AUC and Cmax for bupropion, metoprolol, phenacetin, and tolbutamide, while there was no statistical pharmacokinetic difference for midazolam and omeprazole. Acute H2S poisoning could inhibit the activity of CYP2B6, CYP2D6, CYP1A2, and CYP2C9 in rats. PMID:24790991

Wang, Xianqin; Chen, Mengchun; Chen, Xinxin; Ma, Jianshe; Wen, Congcong; Pan, Jianchun; Hu, Lufeng; Lin, Guanyang

2014-01-01

348

Actions of hydrogen sulfide on sodium transport processes across native distal lung epithelia (Xenopus laevis).  

PubMed

Hydrogen sulfide (H2S) is well known as a highly toxic environmental chemical threat. Prolonged exposure to H2S can lead to the formation of pulmonary edema. However, the mechanisms of how H2S facilitates edema formation are poorly understood. Since edema formation can be enhanced by an impaired clearance of electrolytes and, consequently, fluid across the alveolar epithelium, it was questioned whether H2S may interfere with transepithelial electrolyte absorption. Electrolyte absorption was electrophysiologically measured across native distal lung preparations (Xenopus laevis) in Ussing chambers. The exposure of lung epithelia to H2S decreased net transepithelial electrolyte absorption. This was due to an impairment of amiloride-sensitive sodium transport. H2S inhibited the activity of the Na+/K+-ATPase as well as lidocaine-sensitive potassium channels located in the basolateral membrane of the epithelium. Inhibition of these transport molecules diminishes the electrochemical gradient which is necessary for transepithelial sodium absorption. Since sodium absorption osmotically facilitates alveolar fluid clearance, interference of H2S with the epithelial transport machinery provides a mechanism which enhances edema formation in H2S-exposed lungs. PMID:24960042

Erb, Alexandra; Althaus, Mike

2014-01-01

349

Genetic Targets of Hydrogen Sulfide in Ventilator-Induced Lung Injury - A Microarray Study  

PubMed Central

Recently, we have shown that inhalation of hydrogen sulfide (H2S) protects against ventilator-induced lung injury (VILI). In the present study, we aimed to determine the underlying molecular mechanisms of H2S-dependent lung protection by analyzing gene expression profiles in mice. C57BL/6 mice were subjected to spontaneous breathing or mechanical ventilation in the absence or presence of H2S (80 parts per million). Gene expression profiles were determined by microarray, sqRT-PCR and Western Blot analyses. The association of Atf3 in protection against VILI was confirmed with a Vivo-Morpholino knockout model. Mechanical ventilation caused a significant lung inflammation and damage that was prevented in the presence of H2S. Mechanical ventilation favoured the expression of genes involved in inflammation, leukocyte activation and chemotaxis. In contrast, ventilation with H2S activated genes involved in extracellular matrix remodelling, angiogenesis, inhibition of apoptosis, and inflammation. Amongst others, H2S administration induced Atf3, an anti-inflammatory and anti-apoptotic regulator. Morpholino mediated reduction of Atf3 resulted in elevated lung injury despite the presence of H2S. In conclusion, lung protection by H2S during mechanical ventilation is associated with down-regulation of genes related to oxidative stress and inflammation and up-regulation of anti-apoptotic and anti-inflammatory genes. Here we show that Atf3 is clearly involved in H2S mediated protection. PMID:25025333

Spassov, Sashko; Pfeifer, Dietmar; Strosing, Karl; Ryter, Stefan; Hummel, Matthias; Faller, Simone; Hoetzel, Alexander

2014-01-01

350

Chemiluminescent detection of enzymatically produced hydrogen sulfide: substrate hydrogen bonding influences selectivity for H2S over biological thiols.  

PubMed

Hydrogen sulfide (H2S) is now recognized as an important biological regulator and signaling agent that is active in many physiological processes and diseases. Understanding the important roles of this emerging signaling molecule has remained challenging, in part due to the limited methods available for detecting endogenous H2S. Here we report two reaction-based ChemiLuminescent Sulfide Sensors, CLSS-1 and CLSS-2, with strong luminescence responses toward H2S (128- and 48-fold, respectively) and H2S detection limits (0.7 ± 0.3, 4.6 ± 2.0 ?M, respectively) compatible with biological H2S levels. CLSS-2 is highly selective for H2S over other reactive sulfur, nitrogen, and oxygen species (RSONS) including GSH, Cys, Hcy, S2O3(2–), NO2(–), HNO, ONOO(–), and NO. Despite its similar chemical structure, CLSS-1 displays lower selectivity toward amino acid-derived thiols than CLSS-2. The origin of this differential selectivity was investigated using both computational DFT studies and NMR experiments. Our results suggest a model in which amino acid binding to the hydrazide moiety of the luminol-derived probes provides differential access to the reactive azide in CLSS-1 and CLSS-2, thus eroding the selectivity of CLSS-1 for H2S over Cys and GSH. On the basis of its high selectivity for H2S, we used CLSS-2 to detect enzymatically produced H2S from isolated cystathionine ?-lyase (CSE) enzymes (p < 0.001) and also from C6 cells expressing CSE (p < 0.001). CLSS-2 can readily differentiate between H2S production in active CSE and CSE inhibited with ?-cyanoalanine (BCA) in both isolated CSE enzymes (p < 0.005) and in C6 cells (p < 0.005). In addition to providing a highly sensitive and selective reaction-based tool for chemiluminescent H2S detection and quantification, the insights into substrate–probe interactions controlling the selectivity for H2S over biologically relevant thiols may guide the design of other selective H2S detection scaffolds. PMID:24093945

Bailey, T Spencer; Pluth, Michael D

2013-11-01

351

Solar light-driven photocatalytic hydrogen evolution over ZnIn2S4 loaded with transition-metal sulfides  

NASA Astrophysics Data System (ADS)

A series of Pt-loaded MS/ZnIn2S4 (MS = transition-metal sulfide: Ag2S, SnS, CoS, CuS, NiS, and MnS) photocatalysts was investigated to show various photocatalytic activities depending on different transition-metal sulfides. Thereinto, CoS, NiS, or MnS-loading lowered down the photocatalytic activity of ZnIn2S4, while Ag2S, SnS, or CuS loading enhanced the photocatalytic activity. After loading 1.0 wt.% CuS together with 1.0 wt.% Pt on ZnIn2S4, the activity for H2 evolution was increased by up to 1.6 times, compared to the ZnIn2S4 only loaded with 1.0 wt.% Pt. Here, transition-metal sulfides such as CuS, together with Pt, acted as the dual co-catalysts for the improved photocatalytic performance. This study indicated that the application of transition-metal sulfides as effective co-catalysts opened up a new way to design and prepare high-efficiency and low-cost photocatalysts for solar-hydrogen conversion.

Shen, Shaohua; Chen, Xiaobo; Ren, Feng; Kronawitter, Coleman X.; Mao, Samuel S.; Guo, Liejin

2011-12-01

352

Characterization of SiON/InP MOS structure with sulfidation, fluorination, and hydrogenation  

NASA Astrophysics Data System (ADS)

Liquid phase deposited SiON film on InP with (NH4)2S treatment shows superior electrical characteristics due to the reduction of native oxides and sulfur passivation. Simultaneously, HF in SiON liquid phase deposition solution can effectively reduce residual native oxides on InP and provide fluorine passivation in SiON/InP film and interface. With post-metallization annealing (PMA), hydrogen ions can further passivate defects in SiON/InP film and interface. With these treatments, the PMA-LPD-SiON/(NH4)2S-treated InP MOS structure shows excellent electrical characteristics. With the physical thickness of 5.4 nm, the leakage current densities can be as low as 1.25×10-7 and 6.24×10-7 A/cm2 at ±2 V, and the interface state density is 3.25×1011 cm-2 eV-1.

Lee, Ming-Kwei; Yen, Chih-Feng; Cheng, Chi-Hsuan; Lee, Jung-Chan

2013-09-01

353

Vapor ingestion in Centaur liquid-hydrogen tank  

NASA Technical Reports Server (NTRS)

Vapor ingestion phenomena were investigated using scale models of the Centaur liquid hydrogen tank to determine the height of the free surface of the liquid when vapor is intially ingested into the tank outlet. Data are compared with an analysin and, is general the agreement is very good. Predictions are presented for minimum liquid levels required in the Centaur liquid hydrogen tank in order to prevent vapor ingestion when restarting the engines in space and the quantities of liquid remaining in the tank at vapor ingestion during main engine firing.

Symons, E. P.

1977-01-01

354

The reduction of selenium(IV) by hydrogen sulfide in aqueous solutions  

NASA Astrophysics Data System (ADS)

The rates for the reduction of Se(IV) by sulfides were measured in NaCl solutions as a function of pH (2-10), temperature (10-40 °C) and ionic strength (I = 0.01-1 M). The pseudo first-order rate constant (log k1) showed a complex dependence on pH with values decreasing from pH 2 to a minimum at pH 4.5, then increasing from pH 5.5 to a maximum near pH 8 and decreasing again at pH higher than 8. The values of the overall kinetic constant (k) calculated from the values of k1/[H2S]T can be determined from equations: logk=-0.15pH-1355.5/T+0.44I0.5+7.74 for the pH range 2-4.5 (? = ±0.16), logk=0.28pH-1090.9/T+0.60I0.5+4.68 for the pH range 5.5-7.6 (? = ±0.10) and logk=-0.50pH-1572.1/T+0.45I0.5+12.67 for the pH range 7.7-10 (? = ±0.05), from 10 to 40 °C and from 0.01 to 1 M ionic strength. The effect of pH and ionic strength on the reaction suggests that the reactions in natural waters are due to the following interactions: H2SeO3+H2S ? products HSeO3-+H2S ? products HSeO3-+HS ? products while under strong alkaline conditions (pH > 9) a fourth contribution by SeO32-+HS ? products is also possible. The overall rate expression over the entire pH range investigated can be determined from (H2A = H2SeO3; HA = HSeO3-; A = SeO32-) k=(kH2S-H2A[H]3+kH2S-HAKHA[H]2+kHS-HAKHAK1s[H]+kHS-AKHAKAK1s)/{([H]2+KHA[H]+KAKHA)([H]+K1s)} where kH2S-H2A=2409±566 M min, kH2S-HA=464±233 M min, kHS-HA = 4190 ± 573 M-1 min-1 and kHS-A = 650 ± 382 M-1 min-1 and KHA, KA and K1s are the dissociation constants of selenous acid and hydrogen sulfide. Kinetic runs in natural freshwater samples and natural seawater have confirmed results obtained in simple NaCl solutions suggesting that this reaction may play an important role under anoxic and hypoxic conditions. Sulfide concentrations under these conditions may range from micromolar to millimolar level and Se(IV) half times are in the order of a few hours to minutes, respectively.

Pettine, Maurizio; Gennari, Francesca; Campanella, Luigi; Casentini, Barbara; Marani, Dario

2012-04-01

355

Fractional Consumption of Liquid Hydrogen and Liquid Oxygen During the Space Shuttle Program  

NASA Technical Reports Server (NTRS)

The Space Shuttle uses the propellants, liquid hydrogen and liquid oxygen, to meet part of the propulsion requirements from ground to orbit. The Kennedy Space Center procured over 25 million kilograms of liquid hydrogen and over 250 million kilograms of liquid oxygen during the 3D-year Space Shuttle Program. Because of the cryogenic nature of the propellants, approximately 55% of the total purchased liquid hydrogen and 30% of the total purchased liquid oxygen were used in the Space Shuttle Main Engines. The balance of the propellants were vaporized during operations for various purposes. This paper dissects the total consumption of liqUid hydrogen and liqUid oxygen and determines the fraction attributable to each of the various processing and launch operations that occurred during the entire Space Shuttle Program at the Kennedy Space Center.

Partridge, Jonathan K.

2011-01-01

356

Hydrogen sulfide (H2S) metabolism in mitochondria and its regulatory role in energy production  

PubMed Central

Although many types of ancient bacteria and archea rely on hydrogen sulfide (H2S) for their energy production, eukaryotes generate ATP in an oxygen-dependent fashion. We hypothesize that endogenous H2S remains a regulator of energy production in mammalian cells under stress conditions, which enables the body to cope with energy demand when oxygen supply is insufficient. Cystathionine ?-lyase (CSE) is a major H2S-producing enzyme in the cardiovascular system that uses cysteine as the main substrate. Here we show that CSE is localized only in the cytosol, not in mitochondria, of vascular smooth-muscle cells (SMCs) under resting conditions, revealed by Western blot analysis and confocal microscopy of SMCs transfected with GFP-tagged CSE plasmid. After SMCs were exposed to A23187, thapsigargin, or tunicamycin, intracellular calcium level was increased, and CSE translocated from the cytosol to mitochondria. CSE was coimmunoprecipitated with translocase of the outer membrane 20 (Tom20) in mitochondrial membrane. Tom20 siRNA significantly inhibited mitochondrial translocation of CSE and mitochondrial H2S production. The cysteine level inside mitochondria is approximately three times that in the cytosol. Translocation of CSE to mitochondria metabolized cysteine, produced H2S inside mitochondria, and increased ATP production. Inhibition of CSE activity reversed A23187-stimulated mitochondrial ATP production. H2S improved mitochondrial ATP production in SMCs with hypoxia, which alone decreased ATP production. These results suggest that translocation of CSE to mitochondria on specific stress stimulations is a unique mechanism to promote H2S production inside mitochondria, which subsequently sustains mitochondrial ATP production under hypoxic conditions. PMID:22323590

Fu, Ming; Zhang, Weihua; Wu, Lingyun; Yang, Guangdong; Wang, Rui

2012-01-01

357

Natural near field sinks of hydrogen sulfide from two geothermal power plants in Iceland  

NASA Astrophysics Data System (ADS)

Hydrogen sulfide (H2S) emissions have been growing with the increasing utilization of geothermal resources. Atmospheric H2S concentration has been measured and studied but less is known about the natural sinks of the chemical. This study investigates the atmospheric depletion of H2S within a 35 km distance from two Icelandic power plants. The results showed that atmospheric oxidation by the OH radical was the largest sink in the area. The second largest sink was H2S uptake in surface water, in a neighboring lake, but it was, however, small compared to the reported difference of sulfur amount in the lake in- and outflow. Sulfur was found to accumulate in moss close to the power plants at a maximum rate of about 1500 mg S/kg moss per year and decreased exponentially from the source, being negligible at a distance of a few kilometers. Soil uptake was limited by diffusion of H2S into the porous media and was thus much smaller than the estimated soil uptake potential. Washout with precipitation was estimated to be the smallest sink due to the low H2S reactivity in the precipitation (pH = 5.6), compared to the surface water (pH ˜8). Depletion of H2S from the atmosphere in the study area was estimated to be about 1.2% of the 2012 power plants emissions of over 20,000 tons. Although the uncertainties in the depletion estimates were considerable, most of the H2S emitted from the power plants was strongly indicated to be transported out of the study area as H2S.

Olafsdottir, S.; Gardarsson, S. M.; Andradottir, H. O.

2014-10-01

358

Selenium Inhibits Root Elongation by Repressing the Generation of Endogenous Hydrogen Sulfide in Brassica rapa  

PubMed Central

Selenium (Se) has been becoming an emerging pollutant causing severe phytotoxicity, which the biochemical mechanism is rarely known. Although hydrogen sulfide (H2S) has been suggested as an important exogenous regulator modulating plant physiological adaptions in response to heavy metal stress, whether and how the endogenous H2S regulates Se-induce phytotoxicity remains unclear. In this work, a self-developed specific fluorescent probe (WSP-1) was applied to track endogenous H2S in situ in the roots of Brassica rapa under Se(IV) stress. Se(IV)-induced root growth stunt was closely correlated with the inhibition of endogenous H2S generation in root tips. Se(IV) stress dampened the expression of most LCD and DCD homologues in the roots of B. rapa. By using various specific fluorescent probes for bio-imaging root tips in situ, we found that the increase in endogenous H2S by the application of H2S donor NaHS could significantly alleviate Se(IV)-induced reactive oxygen species (ROS) over-accumulation, oxidative impairment, and cell death in root tips, which further resulted in the recovery of root growth under Se(IV) stress. However, dampening the endogenous H2S could block the alleviated effect of NaHS on Se(IV)-induced phytotoxicity. Finally, the increase in endogenous H2S resulted in the enhancement of glutathione (GSH) in Se(IV)-treated roots, which may share the similar molecular mechanism for the dominant role of H2S in removing ROS by activating GSH biosynthesis in mammals. Altogether, these data provide the first direct evidences confirming the pivotal role of endogenous H2S in modulating Se(IV)-induced phytotoxicity in roots. PMID:25333279

Zheng, Mei-Yu; Xian, Ming; Qi, Zhong-Qiang; Li, You-Qin; Hu, Liang-Bin; Chen, Jian; Yang, Li-Fei

2014-01-01

359

Associations of Ambient Hydrogen Sulfide Exposure with Self-Reported Asthma and Asthma Symptoms  

PubMed Central

Background Whether long-term, low-level hydrogen sulfide (H2S) gas is a cause of health effects, including asthma, is uncertain. Rotorua city, New Zealand, has the largest population exposed, from geothermal sources, to relatively high ambient levels of H2S. In a cross-sectional study, the authors investigated associations with asthma in this population. Methods A total of 1,637 adults, aged 18-65 years, were enrolled during 2008-2010. Residences and workplaces were geocoded. H2S exposures at homes and workplaces were estimated using city-wide networks of passive H2S samplers and kriging to create exposure surfaces. Exposure metrics were based on (1) time-weighted exposures at home and work; and (2) the maximum exposure (home or work). Exposure estimates were entered as quartiles into log-binomial regression models, with covariate data. Results Neither exposure metric showed evidence of increased asthma risk from H2S. However, some suggestion of exposure-related reduced risks for diagnosed asthma and asthma symptoms, particularly wheezing during the last 12 months, emerged. With the maximum exposure metric, the prevalence ratio for wheeze in the highest exposure quartile was 0.80 (0.65, 0.99) and, for current asthma treatment, 0.75 (0.52, 1.08). There was no evidence that this was caused by a “survivor effect”. Conclusions The study provided no evidence that asthma risk increases with H2S exposure. Suggestions of a reduced risk in the higher exposure areas are consistent with recent evidence that H2S has signaling functions in the body, including induction of smooth muscle relaxation and reduction of inflammation. Study limitations, including possible confounding, preclude definitive conclusions. PMID:23453847

Bates, Michael N; Garrett, Nick; Crane, Julian; Balmes, John

2013-01-01

360

Selective Catalytic Oxidation of Hydrogen Sulfide to Elemental Sulfur from Coal-Derived Fuel Gases  

SciTech Connect

The development of low cost, highly efficient, desulfurization technology with integrated sulfur recovery remains a principle barrier issue for Vision 21 integrated gasification combined cycle (IGCC) power generation plants. In this plan, the U. S. Department of Energy will construct ultra-clean, modular, co-production IGCC power plants each with chemical products tailored to meet the demands of specific regional markets. The catalysts employed in these co-production modules, for example water-gas-shift and Fischer-Tropsch catalysts, are readily poisoned by hydrogen sulfide (H{sub 2}S), a sulfur contaminant, present in the coal-derived fuel gases. To prevent poisoning of these catalysts, the removal of H{sub 2}S down to the parts-per-billion level is necessary. Historically, research into the purification of coal-derived fuel gases has focused on dry technologies that offer the prospect of higher combined cycle efficiencies as well as improved thermal integration with co-production modules. Primarily, these concepts rely on a highly selective process separation step to remove low concentrations of H{sub 2}S present in the fuel gases and produce a concentrated stream of sulfur bearing effluent. This effluent must then undergo further processing to be converted to its final form, usually elemental sulfur. Ultimately, desulfurization of coal-derived fuel gases may cost as much as 15% of the total fixed capital investment (Chen et al., 1992). It is, therefore, desirable to develop new technology that can accomplish H{sub 2}S separation and direct conversion to elemental sulfur more efficiently and with a lower initial fixed capital investment.

Gardner, Todd H.; Berry, David A.; Lyons, K. David; Beer, Stephen K.; Monahan, Michael J.

2001-11-06

361

Passive monitors to measure hydrogen sulfide near concentrated animal feeding operations.  

PubMed

Hydrogen sulfide (H2S) is one of many airborne pollutants emitted by concentrated animal feeding operations (CAFOs). However, few studies have characterized ambient H2S levels near these facilities, largely due to the lack of low-cost, reliable, and easily transportable instrumentation available to researchers. We determined intermediate environmental H2S exposure near CAFOs using Radiello passive monitors. First, a laboratory study was performed to determine the accuracy of the device. Next, a total of eight passive H2S monitors were deployed bi-weekly in close proximity (<40 m) to a medium-sized swine confinement for seven months in order to determine the temporal and spatial variability of H2S. Finally, we measured H2S concentrations across two rural Iowa counties to characterize ambient exposure near thirteen CAFOs and two schools. The value of the temperature-adjusted H2S passive diffusion rate provided by the supplier was 29% larger than the 24 h rate determined experimentally. Concentrations of H2S measured near the medium-sized confinement were varied and ranged from 0.2 to 48.6 ppb depending on the sampling period and proximity to a lagoon on the property. Two-week concentrations near the schools were low (<1 ppb), while concentrations near the thirteen CAFOs ranged from 0.1 to 42.9 ppb. The passive monitors were effective in measuring H2S concentrations near a swine CAFO as long as they were exposed for a sufficient period of time (two weeks). Radiello passive monitors are a promising new device in measuring intermediate H2S exposure in rural populations. Measured values in excess of an Iowa state limit of 30 ppb (24 h average) suggest that enforcement actions are needed to mitigate H2S migration from swine CAFOs. PMID:23681048

Pavilonis, Brian T; O'Shaughnessy, Patrick T; Altmaier, Ralph; Metwali, Nervana; Thorne, Peter S

2013-06-01

362

Impacts of meteorological factors on hydrogen sulfide concentration downwind of geothermal power plants  

NASA Astrophysics Data System (ADS)

Hydrogen sulfide (H2S) concentration in the city of Reykjavik, downwind of geothermal power plants has been studied with respect to meteorological factors as the odor and other effects are starting to become a nuisance. The main sources of H2S in Reykjavik City were the Nesjavellir and Hellisheidi Geothermal Power Plants, which are both less than 35 km east of the city. The H2S concentration in Reykjavik was correlated with the H2S emissions from the power plants but was also heavily influenced by weather conditions. The results showed that the H2S concentration at the Grensasvegur Measuring Station was elevated when the wind direction was from 54° to 125°, especially when the wind direction was stable for several hours. The H2S concentration in Reykjavik was highest when the wind speed in the city was between 1.5 and 4 m s-1, and decreased rapidly with higher wind speeds. H2S concentration showed correlation with the air temperature in the city below 3 °C and the concentration rose as the temperature decreased, and the air became more stable and was highest when there was a temperature inversion. The quantitative effects of precipitation on H2S concentration could not be determined in this study although the events with the highest H2S concentration occurred when there was no precipitation. The results showed that favorable conditions for high H2S events can be expected in Reykjavik 2-6 times per year and events with H2S concentration exceeding 50 ?g m-3 might be expected on average about 2 times per year. The results also indicate that events with high H2S concentration can be predicted by using a current weather forecast.

Olafsdottir, S.; Gardarsson, S. M.

2013-10-01

363

Hydrogen sulfide upregulates heme oxygenase-1 expression in rats with volume overload-induced heart failure  

PubMed Central

The present study investigated the role of hydrogen sulfide (H2S), a novel gaseous transmitter, in chronic heart failure (CHF) induced by left-to-right shunt, leading to volume overload. Thirty male Sprague-Dawley rats were randomly divided into four groups: the shunt group, the sham group, the shunt + sodium hydrosulfide (NaHS) group and the sham + NaHS group. CHF was induced in the rats by abdominal aorta-inferior vena cava shunt operation. Rats in the shunt + NaHS and sham + NaHS groups were injected intraperitoneally with NaHS (H2S donor). Haemodynamic parameters were measured 8 weeks after surgery. In addition, left ventricular heme oxygenase (HO)-1 mRNA expression was measured by real-time PCR. Protein expression of HO-1 was evaluated by western blot analysis. Eight weeks after surgery, compared to the sham group, the left ventricular systolic pressure (LVSP) and left ventricular peak rate of contraction and relaxation (LV±dp/dtmax) were significantly reduced; the left ventricular end-diastolic pressure (LVEDP) was significantly increased in the shunt group (all P<0.05). However, NaHS increased LVSP and LV±dp/dtmax (all P<0.05) and decreased LVEDP (P<0.05). Protein expression of HO-1 was significantly decreased in the shunt group compared to that in the sham group (P<0.05). NaHS increased protein expression of HO-1 compared to that in the shunt group (P<0.05). HO-1 mRNA expression was significantly increased in the shunt + NaHS group compared to that in the shunt group (P<0.01). The present study demonstrated that H2S may play a protective role in volume overload-induced CHF by upregulating protein and mRNA expression of HO-1. PMID:24648967

ZHANG, CHAO-YING; LI, XIAO-HUI; ZHANG, TING; FU, JIN; CUI, XIAO-DAI

2013-01-01

364

Relation between malodor, ambient hydrogen sulfide, and health in a community bordering a landfill  

PubMed Central

Background Municipal solid waste landfills are sources of air pollution that may affect the health and quality of life of neighboring communities. Objectives To investigate health and quality of life concerns of neighbors related to landfill air pollution. Methods Landfill neighbors were enrolled and kept twice-daily diaries for 14 d about odor intensity, alteration of daily activities, mood states, and irritant and other physical symptoms between Jan–Nov, 2009. Concurrently, hydrogen sulfide (H2S) air measurements were recorded every 15-min. Relationships between H2S, odor, and health outcomes were evaluated using conditional fixed effects regression models. Results Twenty-three participants enrolled and completed 878 twice-daily diary entries. H2S measurements were recorded over a period of 80 d and 1-hr average H2S = 0.22 ppb (SD = 0.27; range: 0–2.30 ppb). Landfill odor increased 0.63 points (on 5-point Likert-type scale) for every 1 ppb increase in hourly average H2S when the wind was blowing from the landfill towards the community (95% confidence interval (CI): 0.29, 0.91). Odor was strongly associated with reports of alteration of daily activities (odds ratio (OR) = 9.0; 95% CI: 3.5, 23.5), negative mood states (OR = 5.2; 95% CI: 2.8, 9.6), mucosal irritation (OR = 3.7; 95% CI = 2.0, 7.1) and upper respiratory symptoms (OR = 3.9; 95% CI: 2.2, 7.0), but not positive mood states (OR = 0.6; 95% CI: 0.2, 1.5) and gastrointestinal (GI) symptoms (OR = 1.0; 95% CI: 0.4, 2.6). Conclusions Results suggest air pollutants from a regional landfill negatively impact the health and quality of life of neighbors. PMID:21679938

Heaney, Christopher D.; Wing, Steve; Campbell, Robert L.; Caldwell, David; Hopkins, Barbara; Richardson, David; Yeatts, Karin

2011-01-01

365

Impaired hydrogen sulfide synthesis and IL-10 signaling underlie hyperhomocysteinemia-associated exacerbation of colitis  

PubMed Central

Vitamin B deficiencies, which can lead to hyperhomocysteinemia (Hhcy), are commonly reported in patients with inflammatory bowel disease (IBD) and may be a causative underlying factor. However, the mechanism for this effect is not known. Hydrogen sulfide (H2S) is a gaseous mediator that promotes tissue repair and resolution of inflammation. In experimental colitis, a marked increase in colonic H2S synthesis drives ulcer healing and resolution of inflammation. Because H2S synthesis is in part dependent upon enzymes that require vitamin B6 as a cofactor, we tested the hypothesis that Hhcy in rodent models would increase the susceptibility to colitis. In all three models tested, diet-induced Hhcy significantly exacerbated colitis. The usual elevation of colonic H2S synthesis after induction of colitis was absent in all three models of colitis. Administration of an H2S donor to Hhcy rats significantly decreased the severity of colitis. Compared with wild-type mice, interleukin (IL) 10-deficient mice on a normal diet had decreased levels of colonic H2S synthesis, a 40% increase in serum homocysteine, and a phenotype similar to wild-type mice with Hhcy. IL-10–deficient mice fed the vitamin B-deficient diet exhibited more severe colonic inflammation, but the normal elevation of colonic H2S synthesis was absent. Administration of IL-10 to the IL-10–deficient mice restored colonic H2S synthesis and significantly decreased serum homocysteine levels. These results suggest that the exacerbation of colitis in Hhcy is due in part to impaired colonic H2S synthesis. Moreover, IL-10 plays a novel role in promoting H2S production and homocysteine metabolism, which may have therapeutic value in conditions characterized by Hhcy. PMID:25187563

Flannigan, Kyle L.; Agbor, Terence A.; Blackler, Rory W.; Kim, Janice J.; Khan, Waliul I.; Verdu, Elena F.; Ferraz, Jose G. P.; Wallace, John L.

2014-01-01

366

Impaired hydrogen sulfide synthesis and IL-10 signaling underlie hyperhomocysteinemia-associated exacerbation of colitis.  

PubMed

Vitamin B deficiencies, which can lead to hyperhomocysteinemia (Hhcy), are commonly reported in patients with inflammatory bowel disease (IBD) and may be a causative underlying factor. However, the mechanism for this effect is not known. Hydrogen sulfide (H2S) is a gaseous mediator that promotes tissue repair and resolution of inflammation. In experimental colitis, a marked increase in colonic H2S synthesis drives ulcer healing and resolution of inflammation. Because H2S synthesis is in part dependent upon enzymes that require vitamin B6 as a cofactor, we tested the hypothesis that Hhcy in rodent models would increase the susceptibility to colitis. In all three models tested, diet-induced Hhcy significantly exacerbated colitis. The usual elevation of colonic H2S synthesis after induction of colitis was absent in all three models of colitis. Administration of an H2S donor to Hhcy rats significantly decreased the severity of colitis. Compared with wild-type mice, interleukin (IL) 10-deficient mice on a normal diet had decreased levels of colonic H2S synthesis, a 40% increase in serum homocysteine, and a phenotype similar to wild-type mice with Hhcy. IL-10-deficient mice fed the vitamin B-deficient diet exhibited more severe colonic inflammation, but the normal elevation of colonic H2S synthesis was absent. Administration of IL-10 to the IL-10-deficient mice restored colonic H2S synthesis and significantly decreased serum homocysteine levels. These results suggest that the exacerbation of colitis in Hhcy is due in part to impaired colonic H2S synthesis. Moreover, IL-10 plays a novel role in promoting H2S production and homocysteine metabolism, which may have therapeutic value in conditions characterized by Hhcy. PMID:25187563

Flannigan, Kyle L; Agbor, Terence A; Blackler, Rory W; Kim, Janice J; Khan, Waliul I; Verdu, Elena F; Ferraz, Jose G P; Wallace, John L

2014-09-16

367

Vascular complications of cystathionine ?-synthase deficiency: future directions for homocysteine-to-hydrogen sulfide research  

PubMed Central

Homocysteine (Hcy), a cardiovascular and neurovascular disease risk factor, is converted to hydrogen sulfide (H2S) through the transsulfuration pathway. H2S has attracted considerable attention in recent years for many positive effects on vascular health and homeostasis. Cystathionine ?-synthase (CBS) is the first, and rate-limiting, enzyme in the transsulfuration pathway. Mutations in the CBS gene decrease enzymatic activity, which increases the plasma Hcy concentration, a condition called hyperhomocysteinemia (HHcy). Animal models of CBS deficiency have provided invaluable insights into the pathological effects of transsulfuration impairment and of both mild and severe HHcy. However, studies have also highlighted the complexity of HHcy and the need to explore the specific details of Hcy metabolism in addition to Hcy levels per se. There has been a relative paucity of work addressing the dysfunctional H2S production in CBS deficiency that may contribute to, or even create, HHcy-associated pathologies. Experiments using CBS knockout mice, both homozygous (?/?) and heterozygous (+/?), have provided 15 years of new knowledge and are the focus of this review. These murine models present the opportunity to study a specific mechanism for HHcy that matches one of the etiologies in many human patients. Therefore, the goal of this review was to integrate and highlight the critical information gained thus far from models of CBS deficiency and draw attention to critical gaps in knowledge, with particular emphasis on the modulation of H2S metabolism. We include findings from human and animal studies to identify important opportunities for future investigation that should be aimed at generating new basic and clinical understanding of the role of CBS and transsulfuration in cardiovascular and neurovascular disease. PMID:20971760

Beard, Richard S.

2011-01-01

368

Vascular complications of cystathionine ?-synthase deficiency: future directions for homocysteine-to-hydrogen sulfide research.  

PubMed

Homocysteine (Hcy), a cardiovascular and neurovascular disease risk factor, is converted to hydrogen sulfide (H(2)S) through the transsulfuration pathway. H(2)S has attracted considerable attention in recent years for many positive effects on vascular health and homeostasis. Cystathionine ?-synthase (CBS) is the first, and rate-limiting, enzyme in the transsulfuration pathway. Mutations in the CBS gene decrease enzymatic activity, which increases the plasma Hcy concentration, a condition called hyperhomocysteinemia (HHcy). Animal models of CBS deficiency have provided invaluable insights into the pathological effects of transsulfuration impairment and of both mild and severe HHcy. However, studies have also highlighted the complexity of HHcy and the need to explore the specific details of Hcy metabolism in addition to Hcy levels per se. There has been a relative paucity of work addressing the dysfunctional H(2)S production in CBS deficiency that may contribute to, or even create, HHcy-associated pathologies. Experiments using CBS knockout mice, both homozygous (-/-) and heterozygous (+/-), have provided 15 years of new knowledge and are the focus of this review. These murine models present the opportunity to study a specific mechanism for HHcy that matches one of the etiologies in many human patients. Therefore, the goal of this review was to integrate and highlight the critical information gained thus far from models of CBS deficiency and draw attention to critical gaps in knowledge, with particular emphasis on the modulation of H(2)S metabolism. We include findings from human and animal studies to identify important opportunities for future investigation that should be aimed at generating new basic and clinical understanding of the role of CBS and transsulfuration in cardiovascular and neurovascular disease. PMID:20971760

Beard, Richard S; Bearden, Shawn E

2011-01-01

369

Cytoprotective Effects of Hydrogen Sulfide in Novel Rat Models of Non-Erosive Esophagitis  

PubMed Central

Non-erosive esophagitis is a chronic inflammatory condition of the esophagus and is a form of gastroesophageal reflux disease. There are limited treatment options for non-erosive esophagitis, and it often progresses to Barrett’s esophagus and esophageal carcinoma. Hydrogen sulfide has been demonstrated to be a critical mediator of gastric and intestinal mucosal protection and repair. However, roles for H2S in esophageal mucosal defence, inflammation and responses to injury have not been reported. We therefore examined the effects of endogenous and exogenous H2S in rat models of non-erosive esophagitis. Mild- and moderate-severity non-erosive esophagitis was induced in rats through supplementation of drinking water with fructose, plus or minus exposure to water-immersion stress. The effects of inhibitors of H2S synthesis or of an H2S donor on severity of esophagitis was then examined, along with changes in serum levels of a pro- and an anti-inflammatory cytokine (IL-17 and IL-10, respectively). Exposure to water-immersion stress after consumption of the fructose-supplemented water for 28 days resulted in submucosal esophageal edema and neutrophil infiltration and the development of lesions in the muscular lamina and basal cell hyperplasia. Inhibition of H2S synthesis resulted in significant exacerbation of inflammation and injury. Serum levels of IL-17 were significantly elevated, while serum IL-10 levels were reduced. Treatment with an H2S donor significantly reduced the severity of esophageal injury and inflammation and normalized the serum cytokine levels. The rat models used in this study provide novel tools for studying non-erosive esophagitis with a range of severity. H2S contributes significantly to mucosal defence in the esophagus, and H2S donors may have therapeutic value in treating esophageal inflammation and injury. PMID:25333941

Zayachkivska, Oksana; Havryluk, Olena; Hrycevych, Nazar; Bula, Nazar; Grushka, Oksana; Wallace, John L.

2014-01-01

370

GYY4137, a novel hydrogen sulfide-releasing molecule, protects against endotoxic shock in the rat.  

PubMed

GYY4137 (morpholin-4-ium-4-methoxyphenyl(morpholino) phosphinodithioate) is a slow-releasing hydrogen sulfide (H(2)S) donor. Administration of GYY4137 (50 mg/kg, iv) to anesthetized rats 10 min after lipopolysaccharide (LPS; 4 mg/kg, iv) decreased the slowly developing hypotension. GYY4137 inhibited LPS-induced TNF-alpha production in rat blood and reduced the LPS-evoked rise in NF-kappaB activation, inducible nitric oxide synthase/cyclooxygenase-2 expression, and generation of PGE(2) and nitrate/nitrite in RAW 264.7 macrophages. GYY4137 (50 mg/kg, ip) administered to conscious rats 1 or 2 h after (but not 1 h before) LPS decreased the subsequent (4 h) rise in plasma proinflammatory cytokines (TNF-alpha, IL-1beta, IL-6), nitrite/nitrate, C-reactive protein, and L-selectin. GYY4137 administration also decreased the LPS-evoked increase in lung myeloperoxidase activity, increased plasma concentration of the anti-inflammatory cytokine IL-10, and decreased tissue damage as determined histologically and by measurement of plasma creatinine and alanine aminotransferase activity. Time-expired GYY4137 (50 mg/kg, ip) did not affect the LPS-induced rise in plasma TNF-alpha or lung myeloperoxidase activity. GYY4137 also decreased the LPS-mediated upregulation of liver transcription factors (NF-kappaB and STAT-3). These results suggest an anti-inflammatory effect of GYY4137. The possibility that GYY4137 and other slow-releasing H(2)S donors exert anti-inflammatory activity in other models of inflammation and in humans warrants further study. PMID:19375498

Li, Ling; Salto-Tellez, Manuel; Tan, Choon-Hong; Whiteman, Matthew; Moore, Philip K

2009-07-01

371

Hydrogen Sulfide Attenuates Carbon Tetrachloride-Induced Hepatotoxicity, Liver Cirrhosis and Portal Hypertension in Rats  

PubMed Central

Background Hydrogen sulfide (H2S) displays vasodilative, anti-oxidative, anti-inflammatory and cytoprotective activities. Impaired production of H2S contributes to the increased intrahepatic resistance in cirrhotic livers. The study aimed to investigate the roles of H2S in carbon tetrachloride (CCl4)-induced hepatotoxicity, cirrhosis and portal hypertension. Methods and Findings Sodium hydrosulfide (NaHS), a donor of H2S, and DL-propargylglycine (PAG), an irreversible inhibitor of cystathionine ?-lyase (CSE), were applied to the rats to investigate the effects of H2S on CCl4-induced acute hepatotoxicity, cirrhosis and portal hypertension by measuring serum levels of H2S, hepatic H2S producing activity and CSE expression, liver function, activity of cytochrome P450 (CYP) 2E1, oxidative and inflammatory parameters, liver fibrosis and portal pressure. CCl4 significantly reduced serum levels of H2S, hepatic H2S production and CSE expression. NaHS attenuated CCl4-induced acute hepatotoxicity by supplementing exogenous H2S, which displayed anti-oxidative activities and inhibited the CYP2E1 activity. NaHS protected liver function, attenuated liver fibrosis, inhibited inflammation, and reduced the portal pressure, evidenced by the alterations of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), albumin, tumor necrosis factor (TNF)-?, interleukin (IL)-1?, IL-6 and soluble intercellular adhesion molecule (ICAM)-1, liver histology, hepatic hydroxyproline content and ?-smooth muscle actin (SMA) expression. PAG showed opposing effects to NaHS on most of the above parameters. Conclusions Exogenous H2S attenuates CCl4-induced hepatotoxicity, liver cirrhosis and portal hypertension by its multiple functions including anti-oxidation, anti-inflammation, cytoprotection and anti-fibrosis, indicating that targeting H2S may present a promising approach, particularly for its prophylactic effects, against liver cirrhosis and portal hypertension. PMID:22022478

Tan, Gang; Pan, Shangha; Li, Jie; Dong, Xuesong; Kang, Kai; Zhao, Mingyan; Jiang, Xian; Kanwar, Jagat R.; Qiao, Haiquan; Jiang, Hongchi; Sun, Xueying

2011-01-01

372

Hydrogen Sulfide Inhibits Proliferation and Release of IL-8 from Human Airway Smooth Muscle Cells  

PubMed Central

Hydrogen sulfide (H2S) is synthesized intracellularly by the enzymes cystathionine-?-lyase and cystathionine-?-synthase (CBS), and is proposed to be a gasotransmitter with effects in modulating inflammation and cellular proliferation. We determined a role of H2S in airway smooth muscle (ASM) function. ASM were removed from resection or transplant donor lungs and were placed in culture. Proliferation of ASM was induced by FCS and the proinflammatory cytokine, IL-1?. Proliferation of ASM and IL-8 release were measured by bromodeoxyuridine incorporation and ELISA, respectively. Exposure of ASM to H2S “donors” inhibited this proliferation and IL-8 release. Methemoglobin, a scavenger of endogenous H2S, increased DNA synthesis induced by FCS and IL-1?. In addition, methemoglobin increased IL-8 release induced by FCS, but not by IL-1?, indicating a role for endogenous H2S in these systems. Inhibition of CBS, but not cystathionine-?-lyase, reversed the inhibitory effect of H2S on proliferation and IL-8 release, indicating that this is dependent on CBS. CBS mRNA and protein expression were inhibited by H2S donors, and were increased by methemoglobin, indicating that CBS is the main enzyme responsible for endogenous H2S production. Finally, we found that exogenous H2S inhibited the phosphorylation of extracellular signal–regulated kinase–1/2 and p38, which could represent a mechanism by which H2S inhibited cellular proliferation and IL-8 release. In summary, H2S production provides a novel mechanism for regulation of ASM proliferation and IL-8 release. Therefore, regulation of H2S may represent a novel approach to controlling ASM proliferation and cytokine release that is found in patients with asthma. PMID:21297080

Perry, Mark M.; Hui, Christopher K.; Whiteman, Matthew; Wood, Mark E.; Adcock, Ian; Kirkham, Paul; Michaeloudes, Charalambos; Chung, Kian Fan

2013-01-01

373

Hydrogen sulfide inhibits proliferation and release of IL-8 from human airway smooth muscle cells.  

PubMed

Hydrogen sulfide (H(2)S) is synthesized intracellularly by the enzymes cystathionine-?-lyase and cystathionine-?-synthase (CBS), and is proposed to be a gasotransmitter with effects in modulating inflammation and cellular proliferation. We determined a role of H(2)S in airway smooth muscle (ASM) function. ASM were removed from resection or transplant donor lungs and were placed in culture. Proliferation of ASM was induced by FCS and the proinflammatory cytokine, IL-1?. Proliferation of ASM and IL-8 release were measured by bromodeoxyuridine incorporation and ELISA, respectively. Exposure of ASM to H(2)S "donors" inhibited this proliferation and IL-8 release. Methemoglobin, a scavenger of endogenous H(2)S, increased DNA synthesis induced by FCS and IL-1?. In addition, methemoglobin increased IL-8 release induced by FCS, but not by IL-1?, indicating a role for endogenous H(2)S in these systems. Inhibition of CBS, but not cystathionine-?-lyase, reversed the inhibitory effect of H(2)S on proliferation and IL-8 release, indicating that this is dependent on CBS. CBS mRNA and protein expression were inhibited by H(2)S donors, and were increased by methemoglobin, indicating that CBS is the main enzyme responsible for endogenous H(2)S production. Finally, we found that exogenous H(2)S inhibited the phosphorylation of extracellular signal-regulated kinase-1/2 and p38, which could represent a mechanism by which H(2)S inhibited cellular proliferation and IL-8 release. In summary, H(2)S production provides a novel mechanism for regulation of ASM proliferation and IL-8 release. Therefore, regulation of H(2)S may represent a novel approach to controlling ASM proliferation and cytokine release that is found in patients with asthma. PMID:21297080

Perry, Mark M; Hui, Christopher K; Whiteman, Matthew; Wood, Mark E; Adcock, Ian; Kirkham, Paul; Michaeloudes, Charalambos; Chung, Kian Fan

2011-10-01

374

Metabolic and cardiac signaling effects of inhaled hydrogen sulfide and low oxygen in male rats  

PubMed Central

Low concentrations of inhaled hydrogen sulfide (H2S) induce hypometabolism in mice. Biological effects of H2S in in vitro systems are augmented by lowering O2 tension. Based on this, we hypothesized that reduced O2 tension would increase H2S-mediated hypometabolism in vivo. To test this, male Sprague-Dawley rats were exposed to 80 ppm H2S at 21% O2 or 10.5% O2 for 6 h followed by 1 h recovery at room air. Rats exposed to H2S in 10.5% O2 had significantly decreased body temperature and respiration compared with preexposure levels. Heart rate was decreased by H2S administered under both O2 levels and did not return to preexposure levels after 1 h recovery. Inhaled H2S caused epithelial exfoliation in the lungs and increased plasma creatine kinase-MB activity. The effect of inhaled H2S on prosurvival signaling was also measured in heart and liver. H2S in 21% O2 increased Akt-PSer473 and GSK-3?-PSer9 in the heart whereas phosphorylation was decreased by H2S in 10.5% O2, indicating O2 dependence in regulating cardiac signaling pathways. Inhaled H2S and low O2 had no effect on liver Akt. In summary, we found that lower O2 was needed for H2S-dependent hypometabolism in rats compared with previous findings in mice. This highlights the possibility of species differences in physiological responses to H2S. Inhaled H2S exposure also caused tissue injury to the lung and heart, which raises concerns about the therapeutic safety of inhaled H2S. In conclusion, these findings demonstrate the importance of O2 in influencing physiological and signaling effects of H2S in mammalian systems. PMID:22403348

Stein, Asaf; Mao, Zhengkuan; Morrison, Joanna P.; Fanucchi, Michelle V.; Postlethwait, Edward M.; Patel, Rakesh P.; Kraus, David W.; Doeller, Jeannette E.

2012-01-01

375

?-ENaC, a therapeutic target of dexamethasone on hydrogen sulfide induced acute pulmonary edema.  

PubMed

Acute pulmonary edema (APE) is one of the fatal outcomes after exposure to high levels of hydrogen sulfide (H2S), available evidence suggest that dexamethasone (DXM), a potent anti-inflammatory agent, has been widely used or proposed as a therapeutic approach for H2S-induced APE in clinical practice, however, the underlying mechanism remains poorly understood. Ample evidence suggest that epithelial Na(+) channel, especially for the subunit ?-epithelial Na(+) channel (?-ENaC) plays a critical role in alveolar fluid clearance. Therefore, the present study is undertaken to investigate the effects of DXM on ?-ENaC following H2S exposure. The Sprague Dawley rats were exposed to H2S to establish APE model, in parallel, A549 cells were treated with NaHS to establish cell model. In vivo study, we found that DXM significantly attenuated H2S-induced lung histopathological changes and alveolar fluid clearance decrement, however, these preventive effects of DXM can be obviously counteracted by the mifepristone (MIF), the glucocorticoid receptor (GR) blocker. Moreover, DXM markedly attenuated H2S-mediated ?-ENaC down-regulation, and similarly, the process can be partially retarded by MIF. Furthermore, DXM obviously prevented H2S-mediated ERK1/2 activation both in vitro and in vivo study. These results, taken together, suggested that DXM exerted protective effects on H2S-induced APE, and ?-ENaC might be a potential therapeutic target for APE induced by H2S. PMID:25195098

Jiang, Lei; Wang, Jun; Su, Chenglei; Qian, Wenyi; Chen, Junjie; Zhu, Baoli; Zhang, Hengdong; Xiao, Hang; Zhang, Jinsong

2014-09-01

376

Cytoprotective effects of hydrogen sulfide in novel rat models of non-erosive esophagitis.  

PubMed

Non-erosive esophagitis is a chronic inflammatory condition of the esophagus and is a form of gastroesophageal reflux disease. There are limited treatment options for non-erosive esophagitis, and it often progresses to Barrett's esophagus and esophageal carcinoma. Hydrogen sulfide has been demonstrated to be a critical mediator of gastric and intestinal mucosal protection and repair. However, roles for H2S in esophageal mucosal defence, inflammation and responses to injury have not been reported. We therefore examined the effects of endogenous and exogenous H2S in rat models of non-erosive esophagitis. Mild- and moderate-severity non-erosive esophagitis was induced in rats through supplementation of drinking water with fructose, plus or minus exposure to water-immersion stress. The effects of inhibitors of H2S synthesis or of an H2S donor on severity of esophagitis was then examined, along with changes in serum levels of a pro- and an anti-inflammatory cytokine (IL-17 and IL-10, respectively). Exposure to water-immersion stress after consumption of the fructose-supplemented water for 28 days resulted in submucosal esophageal edema and neutrophil infiltration and the development of lesions in the muscular lamina and basal cell hyperplasia. Inhibition of H2S synthesis resulted in significant exacerbation of inflammation and injury. Serum levels of IL-17 were significantly elevated, while serum IL-10 levels were reduced. Treatment with an H2S donor significantly reduced the severity of esophageal injury and inflammation and normalized the serum cytokine levels. The rat models used in this study provide novel tools for studying non-erosive esophagitis with a range of severity. H2S contributes significantly to mucosal defence in the esophagus, and H2S donors may have therapeutic value in treating esophageal inflammation and injury. PMID:25333941

Zayachkivska, Oksana; Havryluk, Olena; Hrycevych, Nazar; Bula, Nazar; Grushka, Oksana; Wallace, John L

2014-01-01

377

Selenium Inhibits Root Elongation by Repressing the Generation of Endogenous Hydrogen Sulfide in Brassica rapa.  

PubMed

Selenium (Se) has been becoming an emerging pollutant causing severe phytotoxicity, which the biochemical mechanism is rarely known. Although hydrogen sulfide (H2S) has been suggested as an important exogenous regulator modulating plant physiological adaptions in response to heavy metal stress, whether and how the endogenous H2S regulates Se-induce phytotoxicity remains unclear. In this work, a self-developed specific fluorescent probe (WSP-1) was applied to track endogenous H2S in situ in the roots of Brassica rapa under Se(IV) stress. Se(IV)-induced root growth stunt was closely correlated with the inhibition of endogenous H2S generation in root tips. Se(IV) stress dampened the expression of most LCD and DCD homologues in the roots of B. rapa. By using various specific fluorescent probes for bio-imaging root tips in situ, we found that the increase in endogenous H2S by the application of H2S donor NaHS could significantly alleviate Se(IV)-induced reactive oxygen species (ROS) over-accumulation, oxidative impairment, and cell death in root tips, which further resulted in the recovery of root growth under Se(IV) stress. However, dampening the endogenous H2S could block the alleviated effect of NaHS on Se(IV)-induced phytotoxicity. Finally, the increase in endogenous H2S resulted in the enhancement of glutathione (GSH) in Se(IV)-treated roots, which may share the similar molecular mechanism for the dominant role of H2S in removing ROS by activating GSH biosynthesis in mammals. Altogether, these data provide the first direct evidences confirming the pivotal role of endogenous H2S in modulating Se(IV)-induced phytotoxicity in roots. PMID:25333279

Chen, Yi; Mo, Hai-Zhen; Zheng, Mei-Yu; Xian, Ming; Qi, Zhong-Qiang; Li, You-Qin; Hu, Liang-Bin; Chen, Jian; Yang, Li-Fei

2014-01-01

378

Endogenous hydrogen sulfide in the rostral ventrolateral medulla/Bötzinger complex downregulates ventilatory responses to hypoxia.  

PubMed

Hydrogen sulfide (H2S) is now recognized as a new gaseous transmitter involved in several brain-mediated responses. The rostral ventrolateral medulla (RVLM)/Bötzinger complex is a region in the brainstem that is involved in cardiovascular and respiratory functions. Recently, it has been shown that exogenous H2S in the RVLM modulates autonomic function and thus blood pressure. In the present study, we investigated whether H2S, endogenously produced in the RVLM/Bötzinger complex, plays a role in the control of hypoxia-induced hyperventilation. Ventilation (VE) was measured before and after bilateral microinjection of Na2S (H2S donor, 0.04, 1 and 2 pmol/100 nl) or aminooxyacetate (AOA, 0.2, 1 and 2 pmol/100 nl, a cystathionine ?-synthase, CBS, inhibitor) into the RVLM/Bötzinger complex followed by a 60-min period of hypoxia (7% inspired O2) or normoxia exposure. Control rats received microinjection of vehicle. Microinjection of vehicle, AOA or Na2S did not change VE in normoxic conditions. Exposure to hypoxia evoked a typical increase in VE. Microinjection of Na2S (2 pmol) followed by hypoxia exposure attenuated the hyperventilation. Conversely, microinjection of AOA (2 pmol) into the RVLM/Bötzinger complex caused an increase in the hypoxia-induced hyperventilation. Thus, endogenous H2S in the RVLM/Bötzinger complex seems to play no role in the maintenance of basal pulmonary ventilation during normoxia whereas during hypoxia H2S has a downmodulatory function. Homogenates of RVLM/Bötzinger complex of animals previously exposed to hypoxia for 60 min exhibited a decreased rate of H2S production. Our data are consistent with the notion that the gaseous messenger H2S synthesis is downregulated in the RVLM/Bötzinger complex during hypoxia favoring hyperventilation. PMID:24953676

Donatti, Alberto F; Soriano, Renato N; Sabino, João P; Branco, Luiz G S

2014-08-15

379

Hydrogen sulfide increases nitric oxide production and subsequent S-nitrosylation in endothelial cells.  

PubMed

Hydrogen sulfide (H2S) and nitric oxide (NO), two endogenous gaseous molecules in endothelial cells, got increased attention with respect to their protective roles in the cardiovascular system. However, the details of the signaling pathways between H2S and NO in endothelia cells remain unclear. In this study, a treatment with NaHS profoundly increased the expression and the activity of endothelial nitric oxide synthase. Elevated gaseous NO levels were observed by a novel and specific fluorescent probe, 5-amino-2-(6-hydroxy-3-oxo-3H-xanthen-9-yl)benzoic acid methyl ester (FA-OMe), and quantified by flow cytometry. Further study indicated an increase of upstream regulator for eNOS activation, AMP-activated protein kinase (AMPK), and protein kinase B (Akt). By using a biotin switch, the level of NO-mediated protein S-nitrosylation was also enhanced. However, with the addition of the NO donor, NOC-18, the expressions of cystathionine-?-lyase, cystathionine-?-synthase, and 3-mercaptopyruvate sulfurtransferase were not changed. The level of H2S was also monitored by a new designed fluorescent probe, 4-nitro-7-thiocyanatobenz-2-oxa-1,3-diazole (NBD-SCN) with high specificity. Therefore, NO did not reciprocally increase the expression of H2S-generating enzymes and the H2S level. The present study provides an integrated insight of cellular responses to H2S and NO from protein expression to gaseous molecule generation, which indicates the upstream role of H2S in modulating NO production and protein S-nitrosylation. PMID:24971375

Chen, Ping-Ho; Fu, Yaw-Syan; Wang, Yun-Ming; Yang, Kun-Han; Wang, Danny Ling; Huang, Bin

2014-01-01

380

Auxin-induced hydrogen sulfide generation is involved in lateral root formation in tomato.  

PubMed

Similar to auxin, hydrogen sulfide (H2S), mainly produced by l-cysteine desulfhydrase (DES; EC 4.4.1.1) in plants, could induce lateral root formation. The objective of this study was to test whether H2S is also involved in auxin-induced lateral root development in tomato (Solanum lycopersicum L.) seedlings. We observed that auxin depletion-induced down-regulation of transcripts of SlDES1, decreased DES activity and endogenous H2S contents, and the inhibition of lateral root formation were rescued by sodium hydrosulfide (NaHS, an H2S donor). However, No additive effects were observed when naphthalene acetic acid (NAA) was co-treated with NaHS (lower than 10 mM) in the induction of lateral root formation. Subsequent work revealed that a treatment with NAA or NaHS could simultaneously induce transcripts of SlDES1, DES activity and endogenous H2S contents, and thereafter the stimulation of lateral root formation. It was further confirmed that H2S or HS(-), not the other sulfur-containing components derived from NaHS, was attributed to the stimulative action. The inhibition of lateral root formation and decreased of H2S metabolism caused by an H2S scavenger hypotaurine (HT) were reversed by NaHS, but not NAA. Molecular evidence revealed that both NaHS- or NAA-induced modulation of some cell cycle regulatory genes, including the up-regulation of SlCDKA;1, SlCYCA2;1, together with simultaneous down-regulation of SlKRP2, were differentially reversed by HT pretreatment. To summarize, above results clearly suggested that H2S might, at least partially, act as a downstream component of auxin signaling to trigger lateral root formation. PMID:24463534

Fang, Tao; Cao, Zeyu; Li, Jiale; Shen, Wenbiao; Huang, Liqin

2014-03-01

381

Research Sensory and Cognitive Effects of Acute Exposure to Hydrogen Sulfide  

E-print Network

BACKGROUND: Some epidemiologic studies have reported compromised cognitive and sensory performance among individuals exposed to low concentrations of hydrogen sulfide (H2S). OBJECTIVES: We hypothesized a dose–response increase in symptom severity and reduction in sensory and cognitive performance in response to controlled H2S exposures. METHODS: In separate exposure sessions administered in random order over three consecutive weeks, 74 healthy subjects [35 females, 39 males; mean age ( ± SD) = 24.7 ± 4.2; mean years of education = 16.5 ± 2.4], were exposed to 0.05, 0.5, and 5 ppm H2S. During each exposure session, subjects completed ratings and tests before H2S exposure (baseline) and during the final hour of the 2-hr exposure period. RESULTS: Dose–response reduction in air quality and increases in ratings of odor intensity, irritation, and unpleasantness were observed. Total symptom severity was not significantly elevated across any exposure condition, but anxiety symptoms were significantly greater in the 5-ppm than in the 0.05-ppm condition. No dose–response effect was observed for sensory or cognitive measures. Verbal learning was compromised during each exposure condition. CONCLUSIONS: Although some symptoms increased with exposure, the magnitude of these changes was relatively minor. Increased anxiety was significantly related to ratings of irritation due to odor. Whether the effect on verbal learning represents a threshold effect of H2S or an effect due to fatigue across exposure requires further investigation. These acute effects in a healthy sample cannot be directly generalized to communities where individuals have other health conditions and concomitant exposures.

Nancy Fiedler; Howard Kipen; Pamela Ohman-strickl; Junfeng Zhang; Clifford Weisel; Robert Laumbach; Kathie Kelly-mcneil; Kelechi Olejeme; Paul Lioy

2007-01-01

382

Endogenous hydrogen sulfide mediates the cardioprotection induced by ischemic postconditioning in the early reperfusion phase.  

PubMed

Hydrogen sulfide (H(2)S), produced by cystanthionine-?-lysase (CSE) in the cardiovascular system, has been suggested to be the third gasotransmitter in addition to nitric oxide (NO) and carbon monoxide (CO). The present study aimed to investigate the role of H(2)S in ischemic postconditioning (IPO) during the early period of reperfusion. IPO with 6 episodes of 10 sec reperfusion followed by 6 episodes of 10 sec ischemia (IPO 2') was administered when reperfusion was initiated. Cardiodynamics and the concentration of H(2)S were measured at 1, 2, 3, 4, 5, 10, 20, 30, 60, 90 and 120 min of reperfusion. Lactate dehydrogenase (LDH) levels and infarct size were determined at the end of the reperfusion. The concentration of H(2)S was stable during the whole experiment in the control group, whereas it reached a peak at the first minute of reperfusion in the ischemia-reperfusion (IR) group. The concentration of H(2)S at the first minute of reperfusion in the IPO 2' group was higher compared to that of the IR group, which correlated with cardioprotection including improved heart contractile function and reduced infarct size and LDH levels. However, the above effects of IPO 2' were attenuated by pre-treatment with blockade of endogenous H(2)S production with DL-propargylglycine for 20 min prior to global ischemia. Furthermore, we found that other forms of IPO, IPO commencing at 1 min after reperfusion (delayed IPO) or lasting only for 1 min (IPO 1'), failed to increase the concentration of H(2)S and protect the myocardium. We conclude that the peak of endogenous H(2)S in the early reperfusion phase is the key to cardioprotection induced by IPO. PMID:23226785

Huang, Yi-E; Tang, Zhi-Han; Xie, Wei; Shen, Xin-Tian; Liu, Mi-Hua; Peng, Xiang-Ping; Zhao, Zhan-Zhi; Nie, DE-Bo; Liu, Lu-Shan; Jiang, Zhi-Sheng

2012-12-01

383

Hydrogen sulfide attenuates the inflammatory response in a mouse burn injury model.  

PubMed

Hydrogen sulfide (H2S) is a naturally occurring gaseous transmitter, which is important in normal physiology and disease. In the present study, the involvement of H2S in the regulation of the immune response induced by burn injury was investigated in mice. Adult male C57BL/6 mice were subjected to burn injuries and treated with vehicle (0.9% sodium chloride, NaCl; 100 ml/kg body weight; subcutaneously, s.c.) or the H2S donor (sodium hydrosulfide, NaHS; 2 mg/kg body weight; s.c.). Compared with the controls, mice which received burn injuries exhibited a significant decrease in plasma H2S levels. Moreover, the levels of tumor necrosis factor (TNF)??, interleukin (IL)?6 and IL?8 significantly increased, while IL?10 levels were decreased, compared with that of the controls in the plasma of mice subjected to burn injuries. Myeloperoxidase (MPO) activity in the liver tissue of injured mice was also markedly higher compared with that of the control group. However, the administration of NaHS significantly decreased the levels of TNF??, IL?6 and IL?8 but increased the levels of IL?10 in the plasma of mice subjected to burn injuries. In addition, the MPO activity was decreased by NaHS. These results suggested that H2S regulates the inflammatory response induced by burn injury by modulating the levels of TNF??, IL?6, IL?8 and IL?10. Thus, it was proposed that the administration of the H2S donor, NaHS, may be a useful therapy against the exaggerated immune response that is associated with burn injury. PMID:23912155

Zeng, Jianhong; Lin, Xianhe; Fan, Haipeng; Li, Changqing

2013-10-01

384

High Turnover Rates for Hydrogen Sulfide Allow for Rapid Regulation of Its Tissue Concentrations  

PubMed Central

Abstract Aims: Hydrogen sulfide (H2S) is a signaling molecule, which influences many physiological processes. While H2S is produced and degraded in many cell types, the kinetics of its turnover in different tissues has not been reported. In this study, we have assessed the rates of H2S production in murine liver, kidney, and brain homogenates at pH 7.4, 37°C, and at physiologically relevant cysteine concentrations. We have also studied the kinetics of H2S clearance by liver, kidney, and brain homogenates under aerobic and anaerobic conditions. Results: We find that the rate of H2S production by these tissue homogenates is considerably higher than background rates observed in the absence of exogenous substrates. An exponential decay of H2S with time is observed and, as expected, is significantly faster under aerobic conditions. The half-life for H2S under aerobic conditions is 2.0, 2.8, and 10.0?min with liver, kidney, and brain homogenate, respectively. Western-blot analysis of the sulfur dioxygenase, ETHE1, involved in H2S catabolism, demonstrates higher steady-state protein levels in liver and kidney versus brain. Innovation: By combining experimental and simulation approaches, we demonstrate high rates of tissue H2S turnover and provide estimates of steady-state H2S levels. Conclusion: Our study reveals that tissues maintain a high metabolic flux of sulfur through H2S, providing a rationale for how H2S levels can be rapidly regulated. Antioxid. Redox Signal. 17, 22–31. PMID:22229551

Vitvitsky, Victor; Kabil, Omer

2012-01-01

385

Pharmacological characterization of the vascular effects of aryl isothiocyanates: is hydrogen sulfide the real player?  

PubMed

Hydrogen sulfide (H?S) is an endogenous gasotransmitter, which mediates important physiological effects in the cardiovascular system. Accordingly, an impaired production of endogenous H?S contributes to the pathogenesis of important cardiovascular disorders, such as hypertension. Therefore, exogenous compounds, acting as H?S-releasing agents, are viewed as promising pharmacotherapeutic agents for cardiovascular diseases. Thus, this paper aimed at evaluating the H?S-releasing properties of some aryl isothiocyanate derivatives and their vascular effects. The release of H?S was determined by amperometry, spectrophotometry and gas/mass chromatography. Moreover, the vascular activity of selected isothiocyanates were tested in rat conductance (aorta) and coronary arteries. Since H?S has been recently reported to act as an activator of vascular Kv7 potassium channels, the possible membrane hyperpolarizing effects of isothiocyanates were tested on human vascular smooth muscle (VSM) cells by spectrofluorescent dyes. Among the tested compounds, phenyl isothiocyanate (PhNCS) and 4-carboxyphenyl isothiocyanate (PhNCS-COOH) exhibited slow-H?S-release, triggered by organic thiols such as L-cysteine. These compounds were endowed with vasorelaxing effects on conductance and coronary arteries. Moreover, these two isothiocyanates caused membrane hyperpolarization of VSM cells. The vascular effects of isothiocyanates were strongly abolished by the selective Kv7-blocker XE991. In conclusion, the isothiocyanate function can be viewed as a suitable slow H?S-releasing moiety, endowed with vasorelaxing and hypotensive effects, typical of this gasotransmitter. Thus, such a chemical moiety can be employed for the development of novel chemical tools for basic studies and promising cardiovascular drugs. PMID:24287004

Martelli, Alma; Testai, Lara; Citi, Valentina; Marino, Alice; Bellagambi, Francesca G; Ghimenti, Silvia; Breschi, Maria C; Calderone, Vincenzo

2014-01-01

386

Systemic hydrogen sulfide administration partially restores normal alveolarization in an experimental animal model of bronchopulmonary dysplasia.  

PubMed

Arrested alveolarization is the pathological hallmark of bronchopulmonary dysplasia (BPD), a complication of premature birth. Here, the impact of systemic application of hydrogen sulfide (H2S) on postnatal alveolarization was assessed in a mouse BPD model. Exposure of newborn mice to 85% O2 for 10 days reduced the total lung alveoli number by 56% and increased alveolar septal wall thickness by 29%, as assessed by state-of-the-art stereological analysis. Systemic application of H2S via the slow-release H2S donor GYY4137 for 10 days resulted in pronounced improvement in lung alveolarization in pups breathing 85% O2, compared with vehicle-treated littermates. Although without impact on lung oxidative status, systemic H2S blunted leukocyte infiltration into alveolar air spaces provoked by hyperoxia, and restored normal lung interleukin 10 levels that were otherwise depressed by 85% O2. Treatment of primary mouse alveolar type II (ATII) cells with the rapid-release H2S donor NaHS had no impact on cell viability; however, NaHS promoted ATII cell migration. Although exposure of ATII cells to 85% O2 caused dramatic changes in mRNA expression, exposure to either GYY4137 or NaHS had no impact on ATII cell mRNA expression, as assessed by microarray, suggesting that the effects observed were independent of changes in gene expression. The impact of NaHS on ATII cell migration was attenuated by glibenclamide, implicating ion channels, and was accompanied by activation of Akt, hinting at two possible mechanisms of H2S action. These data support further investigation of H2S as a candidate interventional strategy to limit the arrested alveolarization associated with BPD. PMID:24508731

Madurga, Alicia; Mižíková, Ivana; Ruiz-Camp, Jordi; Vadász, István; Herold, Susanne; Mayer, Konstantin; Fehrenbach, Heinz; Seeger, Werner; Morty, Rory E

2014-04-01

387

Oxidative stress suppresses the cellular bioenergetic effect of the 3-mercaptopyruvate sulfurtransferase/hydrogen sulfide pathway  

SciTech Connect

Highlights: •Oxidative stress impairs 3-MST-derived H{sub 2}S production in isolated enzyme and in isolated mitochondria. •This impairs the stimulatory bioenergetic effects of H{sub 2}S in hepatocytes. •This has implications for the pathophysiology of diseases with oxidative stress. -- Abstract: Recent data show that lower concentrations of hydrogen sulfide (H{sub 2}S), as well as endogenous, intramitochondrial production of H{sub 2}S by the 3-mercaptopyruvate (3-MP)/3-mercaptopyruvate sulfurtransferase (3-MST) pathway serves as an electron donor and inorganic source of energy to support mitochondrial electron transport and ATP generation in mammalian cells by donating electrons to Complex II. The aim of our study was to investigate the role of oxidative stress on the activity of the 3-MP/3-MST/H{sub 2}S pathway in vitro. Hydrogen peroxide (H{sub 2}O{sub 2}, 100–500 ?M) caused a concentration-dependent decrease in the activity of recombinant mouse 3-MST enzyme. In mitochondria isolated from murine hepatoma cells, H{sub 2}O{sub 2} (50–500 ?M) caused a concentration-dependent decrease in production of H{sub 2}S from 3-MP. In cultured murine hepatoma cells H{sub 2}O{sub 2}, (3–100 ?M), did not result in overall cytotoxicity, but caused a partial decrease in basal oxygen consumption and respiratory reserve rapacity. The positive bioenergetic effect of 3-MP (100–300 nM) was completely abolished by pre-treatment of the cells with H{sub 2}O{sub 2} (50 ?M). The current findings demonstrate that oxidative stress inhibits 3-MST activity and interferes with the positive bioenergetic role of the 3-MP/3-MST/H{sub 2}S pathway. These findings may have implications for the pathophysiology of various conditions associated with increased oxidative stress, such as various forms of critical illness, cardiovascular diseases, diabetes or physiological aging.

Módis, Katalin [Department of Anesthesiology, University of Texas Medical Branch and Shriners Burns Hospital for Children, Galveston, TX (United States)] [Department of Anesthesiology, University of Texas Medical Branch and Shriners Burns Hospital for Children, Galveston, TX (United States); Asimakopoulou, Antonia [Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, Patras (Greece)] [Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, Patras (Greece); Coletta, Ciro [Department of Anesthesiology, University of Texas Medical Branch and Shriners Burns Hospital for Children, Galveston, TX (United States)] [Department of Anesthesiology, University of Texas Medical Branch and Shriners Burns Hospital for Children, Galveston, TX (United States); Papapetropoulos, Andreas [Department of Anesthesiology, University of Texas Medical Branch and Shriners Burns Hospital for Children, Galveston, TX (United States) [Department of Anesthesiology, University of Texas Medical Branch and Shriners Burns Hospital for Children, Galveston, TX (United States); Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, Patras (Greece); Szabo, Csaba, E-mail: szabocsaba@aol.com [Department of Anesthesiology, University of Texas Medical Branch and Shriners Burns Hospital for Children, Galveston, TX (United States)] [Department of Anesthesiology, University of Texas Medical Branch and Shriners Burns Hospital for Children, Galveston, TX (United States)

2013-04-19

388

Spectroscopic investigations of hydrogen bond dynamics in liquid water  

E-print Network

Many of the remarkable physical and chemical properties of liquid water are due to the strong influence hydrogen bonds have on its microscopic dynamics. However, because of the fast timescales involved, there are relatively ...

Fecko, Christopher J., 1975-

2004-01-01

389

Nile-red and Nile-blue-based near-infrared fluorescent probes for in-cellulo imaging of hydrogen sulfide.  

PubMed

Hydrogen sulfide has recently been identified as a biologically responsive species. The design and synthesis of fluorescence probes, which are constructed with Nile-red or Nile-blue fluorophores and a fluorescence-controllable dinitrophenyl group, for hydrogen sulfide are reported in this paper. The Nile-red-dinitrophenyl-ether-group-based probe (1a) is essentially non-fluorescent because of the inhibition of the photo-induced electron-transfer process; when the dinitrobenzene moiety is removed by nucleophilic substitution with the hydrosulfide anion, probe 1a is converted into hydroxy Nile red, eliciting a H2S-induced fluorescence turn-on signal. Furthermore, probe 1a has high selectivity and sensitivity for the hydrosulfide anion, and its potential for biological applications was confirmed by using it for real-time fluorescence imaging of hydrogen sulfide in live HeLa cells. The Nile-blue-dinitrobenzene-based probe (1b) has gradually diminishing brightness in the red-emission channel with increased hydrogen-sulfide concentration. Thus, this paper reports a comparative study of Nile-red and Nile-blue-based hydrogen-sulfide probes. PMID:25258280

Liu, Xiao-Dong; Fan, Chen; Sun, Ru; Xu, Yu-Jie; Ge, Jian-Feng

2014-11-01

390

Feasibility of the hydrogen sulfide test for the assessment of drinking water quality in post-earthquake Haiti.  

PubMed

In 2010, a magnitude 7.0 earthquake struck Haiti, severely damaging the drinking and wastewater infrastructure and leaving millions homeless. Compounding this problem, the introduction of Vibrio cholerae resulted in a massive cholera outbreak that infected over 700,000 people and threatened the safety of Haiti's drinking water. To mitigate this public health crisis, non-government organizations installed thousands of wells to provide communities with safe drinking water. However, despite increased access, Haiti currently lacks the monitoring capacity to assure the microbial safety of any of its water resources. For these reasons, this study was designed to assess the feasibility of using a simple, low-cost method to detect indicators of fecal contamination of drinking water that could be implemented at the community level. Water samples from 358 sources of drinking water in the Léogâne flood basin were screened with a commercially available hydrogen sulfide test and a standard membrane method for the enumeration of thermotolerant coliforms. When compared with the gold standard method, the hydrogen sulfide test had a sensitivity of 65 % and a specificity of 93 %. While the sensitivity of the assay increased at higher fecal coliform concentrations, it never exceeded 88 %, even with fecal coliform concentrations greater than 100 colony-forming units per 100 ml. While its simplicity makes the hydrogen sulfide test attractive for assessing water quality in low-resource settings, the low sensitivity raises concerns about its use as the sole indicator of the presence or absence of fecal coliforms in individual or community water sources. PMID:25182685

Weppelmann, Thomas A; Alam, Meer T; Widmer, Jocelyn; Morrissey, David; Rashid, Mohammed H; De Rochars, Valery M Beau; Morris, J Glenn; Ali, Afsar; Johnson, Judith A

2014-12-01

391

Partitioning of nickel, copper, iridium, rhenium, platinum, and palladium between monosulfide solid solution and sulfide liquid: Effects of composition and temperature  

Microsoft Academic Search

Partitioning of Ni, Cu, and Pt-group elements (Ir, Rh, Pt, Pd) between monosulfide solid solution (Mss) and sulfide liquid has been investigated in the Fe-Ni-Cu-S system at 1000 and 1100°C and one atmosphere pressure. The Nernst partition coefficients (D = wt% in Mss\\/wt% in sulfide liquid) for Ni vary significantly from 0.19 to 1.17, while the values of DCu show

C. Li; S.-J. Barnes; E. Makovicky; J. Rose-Hansen; M. Makovicky

1996-01-01

392

Performance potential of liquid hydrogen fueled, airbreathing, cruise aircraft  

NASA Technical Reports Server (NTRS)

This brochure contains reproductions of slides shown at an oral presentation on the performance potential of liquid hydrogen fueled, airbreathing, cruise aircraft. The plane designed was to be used for commercial transport. The presentation, held on August 25, 1966 at Moffett Field, followed a 9-month study of a wide variety of such aircraft, of promising aircraft configurations, and of potential problem areas of the selected designs. The study included aerodynamics, sonic boom, propulsion, structures, fuel systems, and the cost of liquid hydrogen.

1966-01-01

393

Effect of dispersion and distribution on activity of alumina-supported cadmium sulfide photocatalysts for hydrogen production from water  

SciTech Connect

Activity of a cadmium sulfide photocatalyst, for hydrogen production by decomposition of water using visible light, depends on the protocol used for its preparation. In the present work, unsupported and alumina-supported CdS photocatalysts were prepared by various techniques and characterized by N{sub 2} adsorption, X-ray diffraction, electron diffraction, and X-ray photoelectron spectroscopy. The results indicate that the activity is strongly affected by the dispersion and distribution of CdS on alumina. High dispersion and preferential distribution of CdS on the surface of alumina yield superior activity. The catalyst activity has been explained with the help of its microstructure.

Arora, M.K.; Sinha, A.S.K.; Upadhyay, S.N. [Banaras Hindu Univ., Varanasi (India). Dept. of Chemical Engineering and Technology] [Banaras Hindu Univ., Varanasi (India). Dept. of Chemical Engineering and Technology

1998-04-01

394

Selective oxidation of hydrogen sulfide containing excess water and ammonia over Bi-V-Sb-O catalysts  

Microsoft Academic Search

We investigated the selective oxidation of hydrogen sulfide to elemental sulfur and ammonium thiosulfate by using Bi4V2-xSbxO11-y\\u000a catalysts. The catalysts were prepared by the calcination of a homogeneous mixture of Bi2O3, V2O5, and Sb2O3 obtained by ball-milling adequate amounts of the three oxides. The main phases detected by XRD analysis were Bi4V2O11, Bi1.33V2O6, BiSbO4 and BiVO4. They showed good H2S

Dae-Won Park; Byung-Ha Hwang; Wol-Don Ju; Moon-Il Kim; Kyung-Hoon Kim; Hee-Chul Woo

2005-01-01

395

On the determination of the intramolecular potential energy surface of polyatomic molecules: Hydrogen sulfide and formaldehyde as an illustration  

NASA Astrophysics Data System (ADS)

We present here an approach for determining the Hamiltonian of polyatomic molecules that allows one to successfully solve the problem of potential energy surface (PES) determination via construction and diagonalization of a Hamiltonian matrix of large dimension. In the suggested approach, the Hamiltonian is very simple and can be used both for any "normal" polyatomic molecule and for any isotopic species of a molecule. Molecules with two to four equivalent X-Y bonds are considered, and for illustration of the efficiency of the suggested approach, numerical calculations are made for the three-atomic (hydrogen sulfide) and four-atomic (formaldehyde) molecules.

Ulenikov, O. N.; Bekhtereva, E. S.; Leroy, C.; Gromova, O. V.; Fomchenko, A. L.

2009-06-01

396

Calculation of the intensities of vibrational hydrogen sulfide transitions for remote sensing of high-temperature media  

NASA Astrophysics Data System (ADS)

Integral intensities of vibrational bands are calculated for hydrogen sulfide (H2S) taking into account the Fermi and Darling-Dennison resonances. Components of the dipole moment function in normal coordinates and parameters of the effective vibrational Hamiltonian borrowed from the literature are used as initial data. From several sets of the dipole moment function parameters, we have chosen the set of the parameters computations with which provide the closest agreement with the experimental integral intensities of the H2S bands. As a result, predictive computations of the vibrational band intensities (??? i = 2) are carried out at temperatures in the range 600-1500 K.

Voitsekhovskaya, O. K.; Egorov, O. V.

2012-09-01

397

Cardioprotection induced by hydrogen sulfide preconditioning involves activation of ERK and PI3K\\/Akt pathways  

Microsoft Academic Search

We previously reported that hydrogen sulfide (H2S) preconditioning (SP) produces cardioprotective effects against ischemia in rat cardiac myocytes. The present study aims\\u000a to elucidate the signaling mechanisms involved in SP-induced cardioprotection by investigating the role of extracellular signal\\u000a regulated kinase (ERK1\\/2) and phosphatidylinositol 3-kinase (PI3K)\\/Akt. We found that preconditioning with NaHS (a H2S donor) for three cycles significantly decreased myocardial

Yeshi Hu; Xin Chen; Ting-Ting Pan; Kay Li Neo; Shiau Wei Lee; Ester Sandar Win Khin; Philip K. Moore; Jin-Song Bian

2008-01-01

398

Toxic hydrogen sulfide and dark caves: life-history adaptations in a livebearing fish (Poecilia mexicana, Poeciliidae).  

PubMed

Life-history traits are very sensitive to extreme environmental conditions, because resources that need to be invested in somatic maintenance cannot be invested in reproduction. Here we examined female life-history traits in the Mexican livebearing fish Poecilia mexicana from a variety of benign surface habitats, a creek with naturally occurring toxic hydrogen sulfide (H2S), a sulfidic cave, and a non-sulfidic cave. Previous studies revealed pronounced genetic and morphological divergence over very small geographic scales in this system despite the absence of physical barriers, suggesting that local adaptation to different combinations of two selection factors, toxicity (H2S) and darkness, is accompanied by very low rates of gene flow. Hence, we investigated life-history divergence between these populations in response to the selective pressures of darkness and/or toxicity. Our main results show that toxicity and darkness both select for (or impose constraints on) the same female trait dynamics: reduced fecundity and increased offspring size. Since reduced fecundity in the sulfur cave population was previously shown to be heritable, we discuss how divergent life-history evolution may promote further ecological divergence: for example, reduced fecundity and increased offspring autonomy are clearly beneficial in extreme environments, but fish with these traits are outcompeted in benign habitats. PMID:20503881

Riesch, Rüdiger; Plath, Martin; Schlupp, Ingo

2010-05-01

399

Hydrogen Sulfide Ameliorates Tobacco Smoke-Induced Oxidative Stress and Emphysema in Mice  

PubMed Central

Abstract Aims The mutual interactions between reactive oxygen species, airway inflammation, and alveolar cell death play crucial role in the pathogenesis of chronic obstructive pulmonary disease (COPD). In the present study, we investigated the possibility that hydrogen sulfide (H2S) donor sodium hydrosulfide (NaHS) might be a novel option for intervention in COPD. Results We used a mouse model of tobacco smoke (TS)-induced emphysema. Mice were injected with H2S donor NaHS (50??mol/kg in 0.25?ml phosphate buffer saline, intraperitoneally) or vehicle daily before exposed to TS for 1?h/day, 5 days/week for 12 and 24 weeks. We found that NaHS ameliorated TS-induced increase in mean linear intercepts, the thickness of bronchial walls, and the numbers of total cell counts as well as neutrophils, monocytes, and tumor necrosis factor ? in bronchial alveolar lavage. Moreover, NaHS reduced increases in right ventricular systolic pressure, the thickness of pulmonary vascular walls, and the ratio of RV/LV+S in TS-exposed mice. Further, TS exposure for 12 and 24 weeks reduced the protein contents of cystathionine ?-lyase (CGL), cystathionine ?-synthetase (CBS), nuclear erythroid-related factor 2 (Nrf2), Pser473-Akt, as well as glutathione/oxidized glutathione ratio in the lungs. TS-exposed lungs exhibited large amounts of 8-hydroxyguanine-positive and terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells. Treatment with NaHS increased Pser473-Akt and attenuated TS-induced reduction of CGL, CBS, and Nrf2 as well as glutathione/oxidized glutathione ratio in the lungs. NaHS also reduced amounts of 8-hydroxyguanine-positive, terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells and active caspase-3 in TS-exposed lungs. Additionally, knocking-down Akt protein abolished the protective effects of NaHS against TS-induced apoptosis and downregulation of Nrf2, CGL, and CBS in pulmonary artery endothelial cells. Conclusion These results indicate that NaHS protects against TS-induced oxidative stress, airway inflammation, and remodeling and ameliorates the development of emphysema and pulmonary hypertension. H2S donors have therapeutic potential for the prevention and treatment of COPD caused by TS. Antioxid. Redox Signal. 15, 2121–2134. PMID:21504365

Han, Weihong; Dong, Zheng; Dimitropoulou, Christiana

2011-01-01

400

Hydrogen sulfide protects blood-brain barrier integrity following cerebral ischemia.  

PubMed

By using two structurally unrelated hydrogen sulfide (H2 S) donors 5-(4-methoxyphenyl) -3H-1, 2-dithiole-3-thione (ADT) and sodium hydrosulfide (NaHS), this study investigated if H2 S protected blood-brain barrier (BBB) integrity following middle cerebral artery occlusion (MCAO). ICR mice underwent MCAO and received H2 S donors at 3 h after reperfusion. Infarction, neurological scores, brain edema, Evans blue (EB) extravasation, and tight junction protein expression were examined at 48 h after MCAO. We also investigated if ADT protected BBB integrity by suppressing post-ischemic inflammation-induced Matrix Metalloproteimase-9 (MMP9) and Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX). ADT increased blood H2 S concentrations, decreased infarction, and improved neurological deficits. Particularly, ADT reduced EB extravasation, brain edema and preserved expression of tight junction proteins in the ischemic brain. NaHS also increased blood H2 S levels and reduced EB extravasation following MCAO. Moreover, ADT inhibited expression of pro-inflammatory markers induced Nitric Oxide Synthase (iNOS) and IL-1? while enhanced expression of anti-inflammatory markers arginase 1 and IL-10 in the ischemic brain. Accordingly, ADT attenuated ischemia-induced expression and activity of MMP9. Moreover, ADT reduced NOX-4 mRNA expression, NOX activity, and inhibited nuclear translocation of Nuclear Factor Kappa-B (NF-?B) in the ischemic brain. In conclusion, H2 S donors protected BBB integrity following experimental stroke possibly by acting through NF-?B inhibition to suppress neuroinflammation induction of MMP9 and NOX4-derived free radicals. To determine H2 S effects on blood-brain barrier (BBB) disruption following stroke, we used two structurally unrelated H2 S donors ADT and NaHS. Both ADT and NaHS remarkably protected BBB integrity following experimental stroke. The slow-releasing donor ADT also reduced post-ischemic inflammation-induced expression and activity of MMP9 and NOX4 in the ischemic brain possibly by inhibiting NF-?B activation. PMID:24673410

Wang, Yali; Jia, Jia; Ao, Guizhen; Hu, Lifang; Liu, Hui; Xiao, Yunqi; Du, Huaping; Alkayed, Nabil J; Liu, Chun-Feng; Cheng, Jian

2014-06-01

401

Hydrogen sulfide mediates the anti-survival effect of sulforaphane on human prostate cancer cells  

SciTech Connect

Hydrogen sulfide (H{sub 2}S) is a novel gasotransmitter that regulates cell proliferation and other cellular functions. Sulforaphane (SFN) is a sulfur-containing compound that exhibits anticancer properties, and young sprouts of broccoli are particularly rich in SFN. There is consistent epidemiological evidence that the consumption of sulfur-containing vegetables, such as garlic and cruciferous vegetables, may help reduce the occurrence of prostate cancer. Here we found that a large amount of H{sub 2}S is released when SFN is added into cell culture medium or mixed with mouse liver homogenates, respectively. Both SFN and NaHS (a H{sub 2}S donor) decreased the viability of PC-3 cells (a human prostate cancer cell line) in a dose-dependent manner, and supplement of methemoglobin or oxidized glutathione (two H{sub 2}S scavengers) reversed SFN-reduced cell viability. We further found both cystathionine gamma-lyase (CSE) and cystathionine beta-synthase are expressed in PC-3 cells and mouse prostate tissues. H{sub 2}S production in prostate tissues from CSE knockout mice was only 20% of that from wild-type mice, suggesting CSE is a major H{sub 2}S-producing enzyme in prostate. CSE overexpression enhanced H{sub 2}S production and inhibited cell viability in PC-3 cells. In addition, both SFN and NaHS activated p38 mitogen-activated protein kinases (MAPK) and c-Jun N-terminal kinase (JNK). Pre-treatment of PC-3 cells with methemoglobin decreased SFN-stimulated MAPK activities. Suppression of both p38 MAPK and JNK reversed H{sub 2}S- or SFN-reduced viability of PC-3 cells. Our results demonstrated that H{sub 2}S mediates the inhibitory effect of SFN on the proliferation of PC-3 cells, which suggests that H{sub 2}S-releasing diet or drug might be beneficial in the treatment of prostate cancer. Highlights: Black-Right-Pointing-Pointer A large amount of H{sub 2}S is released from sulforaphane. Black-Right-Pointing-Pointer H{sub 2}S mediates the anti-survival effect of sulforaphane on human prostate cancer cells. Black-Right-Pointing-Pointer Cystathionine gamma-lyase is a major H{sub 2}S-producing enzyme in prostate tissues. Black-Right-Pointing-Pointer p38 MAPK and JNK contribute to H{sub 2}S and sulforaphane-reduced viability in prostate cancer cells.

Pei, Yanxi [Department of Biology, Lakehead University, Thunder Bay (Canada) [Department of Biology, Lakehead University, Thunder Bay (Canada); College of Life Science, Shanxi University, Taiyuan (China); Wu, Bo [Department of Biology, Lakehead University, Thunder Bay (Canada) [Department of Biology, Lakehead University, Thunder Bay (Canada); Department of Pathophysiology, Harbin Medical University, Harbin (China); Cao, Qiuhui [Department of Biology, Lakehead University, Thunder Bay (Canada)] [Department of Biology, Lakehead University, Thunder Bay (Canada); Wu, Lingyun [Department of Pathophysiology, Harbin Medical University, Harbin (China) [Department of Pathophysiology, Harbin Medical University, Harbin (China); Department of Pharmacology, University of Saskatchewan, Saskatoon (Canada); Yang, Guangdong, E-mail: gyang@lakeheadu.ca [The School of Kinesiology, Lakehead University, Thunder Bay (Canada)] [The School of Kinesiology, Lakehead University, Thunder Bay (Canada)

2011-12-15

402

Hydrogen Sulfide Plays a Key Role in the Inhibitory Neurotransmission to the Pig Intravesical Ureter  

PubMed Central

According to previous observations nitric oxide (NO), as well as an unknown nature mediator are involved in the inhibitory neurotransmission to the intravesical ureter. This study investigates the hydrogen sulfide (H2S) role in the neurogenic relaxation of the pig intravesical ureter. We have performed western blot and immunohistochemistry to study the expression of the H2S synthesis enzymes cystathionine ?-lyase (CSE) and cystathionine ?-synthase (CBS), measurement of enzymatic production of H2S and myographic studies for isometric force recording. Immunohistochemical assays showed a high CSE expression in the intravesical ureter muscular layer, as well as a strong CSE-immunoreactivity within nerve fibres distributed along smooth muscle bundles. CBS expression, however, was not consistently observed. On ureteral strips precontracted with thromboxane A2 analogue U46619, electrical field stimulation (EFS) and the H2S donor P-(4-methoxyphenyl)-P-4-morpholinylphosphinodithioic acid (GYY4137) evoked frequency- and concentration-dependent relaxations. CSE inhibition with DL-propargylglycine (PPG) reduced EFS-elicited responses and a combined blockade of both CSE and NO synthase (NOS) with, respectively, PPG and NG-nitro-L-arginine (L-NOARG), greatly reduced such relaxations. Endogenous H2S production rate was reduced by PPG, rescued by addition of GYY4137 and was not changed by L-NOARG. EFS and GYY4137 relaxations were also reduced by capsaicin-sensitive primary afferents (CSPA) desensitization with capsaicin and blockade of ATP-dependent K+ (KATP) channels, transient receptor potential A1 (TRPA1), transient receptor potential vanilloid 1 (TRPV1), vasoactive intestinal peptide/pituitary adenylyl cyclase-activating polypeptide (VIP/PACAP) and calcitonin gene-related peptide (CGRP) receptors with glibenclamide, HC030031, AMG9810, PACAP6–38 and CGRP8–37, respectively. These results suggest that H2S, synthesized by CSE, is involved in the inhibitory neurotransmission to the pig intravesical ureter, through an NO-independent pathway, producing smooth muscle relaxation via KATP channel activation. H2S also promotes the release of inhibitory neuropeptides, as PACAP 38 and/or CGRP from CSPA through TRPA1, TRPV1 and related ion channel activation. PMID:25415381

Fernandes, Vítor S.; Ribeiro, Ana S. F.; Martínez, Pilar; López-Oliva, María Elvira; Barahona, María Victoria; Orensanz, Luis M.; Martínez-Sáenz, Ana; Recio, Paz; Benedito, Sara; Bustamante, Salvador; García-Sacristán, Albino; Prieto, Dolores; Hernández, Medardo

2014-01-01

403

cGMP-Dependent Protein Kinase Contributes to Hydrogen Sulfide-Stimulated Vasorelaxation  

PubMed Central

A growing body of evidence suggests that hydrogen sulfide (H2S) is a signaling molecule in mammalian cells. In the cardiovascular system, H2S enhances vasodilation and angiogenesis. H2S-induced vasodilation is hypothesized to occur through ATP-sensitive potassium channels (KATP); however, we recently demonstrated that it also increases cGMP levels in tissues. Herein, we studied the involvement of cGMP-dependent protein kinase-I in H2S-induced vasorelaxation. The effect of H2S on vessel tone was studied in phenylephrine-contracted aortic rings with or without endothelium. cGMP levels were determined in cultured cells or isolated vessel by enzyme immunoassay. Pretreatment of aortic rings with sildenafil attenuated NaHS-induced relaxation, confirming previous findings that H2S is a phosphodiesterase inhibitor. In addition, vascular tissue levels of cGMP in cystathionine gamma lyase knockouts were lower than those in wild-type control mice. Treatment of aortic rings with NaHS, a fast releasing H2S donor, enhanced phosphorylation of vasodilator-stimulated phosphoprotein in a time-dependent manner, suggesting that cGMP-dependent protein kinase (PKG) is activated after exposure to H2S. Incubation of aortic rings with a PKG-I inhibitor (DT-2) attenuated NaHS-stimulated relaxation. Interestingly, vasodilatory responses to a slowly releasing H2S donor (GYY 4137) were unaffected by DT-2, suggesting that this donor dilates mouse aorta through PKG-independent pathways. Dilatory responses to NaHS and L-cysteine (a substrate for H2S production) were reduced in vessels of PKG-I knockout mice (PKG-I?/?). Moreover, glibenclamide inhibited NaHS-induced vasorelaxation in vessels from wild-type animals, but not PKG-I?/?, suggesting that there is a cross-talk between KATP and PKG. Our results confirm the role of cGMP in the vascular responses to NaHS and demonstrate that genetic deletion of PKG-I attenuates NaHS and L-cysteine-stimulated vasodilation. PMID:23285278

Bucci, Mariarosaria; Papapetropoulos, Andreas; Vellecco, Valentina; Zhou, Zongmin; Zaid, Altaany; Giannogonas, Panagiotis; Cantalupo, Anna; Dhayade, Sandeep; Karalis, Katia P.; Wang, Rui; Feil, Robert; Cirino, Giuseppe

2012-01-01

404

cGMP-dependent protein kinase contributes to hydrogen sulfide-stimulated vasorelaxation.  

PubMed

A growing body of evidence suggests that hydrogen sulfide (H?S) is a signaling molecule in mammalian cells. In the cardiovascular system, H?S enhances vasodilation and angiogenesis. H?S-induced vasodilation is hypothesized to occur through ATP-sensitive potassium channels (K(ATP)); however, we recently demonstrated that it also increases cGMP levels in tissues. Herein, we studied the involvement of cGMP-dependent protein kinase-I in H?S-induced vasorelaxation. The effect of H?S on vessel tone was studied in phenylephrine-contracted aortic rings with or without endothelium. cGMP levels were determined in cultured cells or isolated vessel by enzyme immunoassay. Pretreatment of aortic rings with sildenafil attenuated NaHS-induced relaxation, confirming previous findings that H?S is a phosphodiesterase inhibitor. In addition, vascular tissue levels of cGMP in cystathionine gamma lyase knockouts were lower than those in wild-type control mice. Treatment of aortic rings with NaHS, a fast releasing H?S donor, enhanced phosphorylation of vasodilator-stimulated phosphoprotein in a time-dependent manner, suggesting that cGMP-dependent protein kinase (PKG) is activated after exposure to H?S. Incubation of aortic rings with a PKG-I inhibitor (DT-2) attenuated NaHS-stimulated relaxation. Interestingly, vasodilatory responses to a slowly releasing H?S donor (GYY 4137) were unaffected by DT-2, suggesting that this donor dilates mouse aorta through PKG-independent pathways. Dilatory responses to NaHS and L-cysteine (a substrate for H?S production) were reduced in vessels of PKG-I knockout mice (PKG-I?/?). Moreover, glibenclamide inhibited NaHS-induced vasorelaxation in vessels from wild-type animals, but not PKG-I?/?, suggesting that there is a cross-talk between K(ATP) and PKG. Our results confirm the role of cGMP in the vascular responses to NaHS and demonstrate that genetic deletion of PKG-I attenuates NaHS and L-cysteine-stimulated vasodilation. PMID:23285278

Bucci, Mariarosaria; Papapetropoulos, Andreas; Vellecco, Valentina; Zhou, Zongmin; Zaid, Altaany; Giannogonas, Panagiotis; Cantalupo, Anna; Dhayade, Sandeep; Karalis, Katia P; Wang, Rui; Feil, Robert; Cirino, Giuseppe

2012-01-01

405

Influences of water vapor on Cr(VI) reduction by gaseous hydrogen sulfide.  

PubMed

In Situ Gaseous Reduction (ISGR) using hydrogen sulfide (H2S) is a technology developed for soil remediation by reductive immobilization of contaminants such as hexavalent chromium (Cr(VI)). Deploying the technology requires us to obtain a much-improved understanding of the interactions among the contaminants, H2S, and various soil components. In this study, Cr(VI) reduction by gaseous H2S was examined under various relative humidities (0-96.7%), concentrations of Cr(VI) (127-475 microg/g of solid), and H2S (0-800 ppm(v)) and by using Cr(VI) compounds with different solubilities. Glass beads with various average diameters (GA = 0.600 mm; GB = 0.212-0.300 mm; and GC = 0.106 mm) and silica (SA = 0.075-0.150 mm) were used as matrices to support K2CrO4, CaCrO4, PbCrO4, or BaCrO4, and reduction of these compounds by gaseous H2S was monitored by Cr(VI) analysis following extractions with distilled water or hot alkali solution. The results showed that Cr(VI) reduction relied on both the relative humidity of the gaseous stream and the size of particles onto which Cr(VI) was deposited. The relative humidity required for fast Cr(VI) reduction was 85% for GA, 61% for GB, 6% for SA, and 0% for GC. It was believed that a water film formed on the particle surfaces under appropriate humidity conditions, resulting in Cr(VI) compound dissolution and subsequent reduction. For nonsoluble Cr(VI) compounds including PbCrO4 and BaCrO4, no reduction by H2S was observed, even at high relative humidity (96.7%), due to lack of dissolution. This study indicated that ISGR treatment in soils requires appropriate moisture content in the subsurface or maintaining a suitable humidity in the treatment gas stream to maximize chromium immobilization. PMID:14594390

Hua, Bin; Deng, Baolin

2003-10-15

406

Role of hydrogen sulfide in the pain processing of non-diabetic and diabetic rats.  

PubMed

Hydrogen sulfide (H2S) is a gasotransmitter endogenously generated from the metabolism of L-cysteine by action of two main enzymes called cystathionine ?-synthase (CBS) and cystathionine ?-lyase (CSE). This gas has been involved in the pain processing and insulin resistance produced during diabetes development. However, there is no evidence about its participation in the peripheral neuropathy induced by this metabolic disorder. Experimental diabetes was induced by streptozotocin (50mg/kg, i.p.) in female Wistar rats. Streptozotocin injection increased formalin-evoked flinching in diabetic rats as compared to non-diabetic rats after 2 weeks. Peripheral administration of NaHS (an exogenous donor of H2S) and L-cysteine (an endogenous donor of H2S) dose-dependently increased flinching behavior in diabetic and non-diabetic rats. Contrariwise, hydroxylamine (HA, a CBS inhibitor) and DL-propargylglycine (PPG, a CSE inhibitor) decreased formalin-induced nociceptive behavior in both experimental groups. In addition, an ineffective dose of HA and PPG partially prevented the L-cysteine-induced hyperalgesia in diabetic and non-diabetic rats. Interestingly, HA and PPG were three order of magnitude more potent in diabetic rats respect to non-diabetic rats, whereas NaHS was ten times more potent in the streptozotocin-diabetic group. Nine to 11 weeks after diabetes induction, tactile allodynia was observed in the streptozotocin-injected rats. On this condition, subcutaneous administration of PPG or HA reduced tactile allodynia in diabetic rats. Paradoxically, H2S levels were decreased in nerve sciatic, dorsal root ganglion and spinal cord, but not paw nor blood plasma, during diabetes-associated peripheral neuropathy development. Collectively, results suggest that H2S synthesized by CBS and CSE participate in formalin-induced nociception in diabeti