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1.
Water Sci Technol ; 81(6): 1319-1328, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32597417

RESUMO

Biogas, which typically consists of about 50-70% of methane gas, is produced by anaerobic digestion of organic waste and wastewater. Biogas is considered an important energy resource with much potential; however, its application is low due to its low quality. In this regard, upgrading it to natural gas quality (above 90% methane) will broaden its application. In this research, a novel ex-situ immobilized biomethanation bioreactor (IBBR) was developed for biologically upgrading biogas by reducing CO2 to CH4 using hydrogen gas as an electron donor. The developed process is based on immobilized microorganisms within a polymeric matrix enabling the application of high recirculation to increase the hydrogen bioavailability. This generates an increase in the consumption rate of hydrogen and the production rate of methane. This process was successfully demonstrated at laboratory-scale system, where the developed process led to a production of 80-89% methane with consumption of more than 93% of the fed hydrogen. However, a lower methane content was achieved in the bench-scale system, likely as a result of lower hydrogen consumption (63-90%). To conclude, the IBBRs show promising results with a potential for simple and effective biogas upgrading.


Assuntos
Biocombustíveis , Reatores Biológicos , Hidrogênio , Metano , Águas Residuárias
2.
Bioresour Technol ; 310: 123443, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32353767

RESUMO

This study explores the catalytic application of waste clam shell in hydrothermal liquefaction (HTL) of microalgae (Scenedesmus obliquus) for liquid hydrocarbons production. Novel catalyst (calcium hydroxide) was derived from clam shells. Catalytic HTL was performed at varying temperature of 240-320 °C for catalyst load (0.2-1 wt%) at a reaction time of 60 min. Bio-oil yield was maximum (39.6 wt%) at a temperature of 300 °C for catalyst load of 0.6 wt% at a reaction time of 60 min with calorific value of 35.01 MJ/kg. Compounds like phenols, aromatic hydrocarbons, acids and aldehydes were detected in bio-oil through Gas Chromatography Mass Spectrophotometry (GC-MS). Gasification of microalgae with waste solid residue obtained from HTL was carried out for hydrogen production. Valuable hydrogen gas production was maximum (37 wt%) at a temperature of 400 °C for 3 wt% of solid residue. Water-gas shift, methanation and steam reforming reactions favoured the hydrogen gas production.


Assuntos
Bivalves , Microalgas , Scenedesmus , Animais , Biocombustíveis , Hidrogênio , Temperatura , Água
3.
Bioresour Technol ; 310: 123447, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32353772

RESUMO

In the present study, isolation and identification of hydrogen producing strains from sugar and food industry wastewater were reported. From 48 isolates in both the wastewater, initial batch studies led to the use of four effective strains, which were identified using 16S rRNA gene sequencing as Bacillus thuringiensis-FH1, Comamonas testosteroni-FB1, Klebsiella pneumoniae-FA2 and Bacillus cereus-SB2, respectively. Further optimization studies were done at various pH values (5-8) and wastewater concentrations (10-100%). In the optimized batch experimentation, K. pneumoniae-FA2 excelled with the maximum cumulative hydrogen production of 880.93 ± 44.0 mL/L. A 3 L bioreactor was employed for effective hydrogen production, which conferred that K. pneumoniae-FA2, surpassed the other three with the maximum hydrogen yield of 3.79 ± 0.04 mol H2/mol glucose. Bioelectricity production by K. pneumoniae-FA2 was also investigated in the microbial fuel cell at the optimized conditions to demonstrate its versatility in energy applications.


Assuntos
Fontes de Energia Bioelétrica , Resíduos Industriais , Reatores Biológicos , Fermentação , Hidrogênio , RNA Ribossômico 16S , Águas Residuárias
4.
Bioresour Technol ; 310: 123457, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32371033

RESUMO

The depletion of fossil fuel reserves and the growing demand for alternative energy sources are the main drivers of biomass and carbonaceous waste utilization. Particularly, non-edible lignocellulosic biomass is the most attractive renewable feedstock due to its abundance. Pyrolysis of biomass produces highly oxygenated compounds with oxygen content >35 wt%. The cost-effective elimination of oxygen from the pyrolysis oil is the most challenging task impeding the commercialization of biomass to biofuel processes. The effective hydrogen/carbon ratio in biomass pyrolysis oil is low (0.3), requiring external hydrogen supply to produce hydrocarbon-rich oils. Exploiting hydrogen-rich feedstock particularly, solid waste (plastic, tyre and scum) and other low-cost feedstock (lubricant oil, methane, methanol, and ethanol) offer an eco-friendly solution to upgrade the produced bio-oil. Multi-functional catalysts that are capable of cleaving oxygen, promoting hydrogen transfer and depolymerisation must be developed to produce hydrocarbon-rich oil from biomass. This review compares catalytic co-pyrolysis studies based on zeolites, mesoporous silica and metal oxides. Furthermore, a wide range of catalyst modifications and the role of each feedstock were summarised to give a complete picture of the progress made on biomass co-pyrolysis research and development.


Assuntos
Hidrogênio , Pirólise , Biocombustíveis , Biomassa , Catálise , Temperatura Alta
5.
Phys Rev Lett ; 124(17): 174501, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32412279

RESUMO

Very lean hydrogen flames were thought to quench in narrow confined geometries. We show for the first time how flames with very low fuel concentration undergo an unprecedented propagation in narrow gaps: H_{2}-air flames can survive very adverse conditions by breaking the reaction front into isolated flame cells that travel steadily in straight lines or split to perform a fractal-like propagation that resembles the pathway of starving fungi or bacteria. The combined effect of hydrogen mass diffusivity and intense heat losses act as the two main mechanisms that explain the experimental observations.


Assuntos
Hidrogênio/química , Modelos Teóricos , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Fogo , Fungos/crescimento & desenvolvimento , Fungos/metabolismo , Modelos Biológicos , Modelos Químicos
6.
Bioresour Technol ; 311: 123494, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32413640

RESUMO

This paper proposes the use of hydrogen oxidizing bacteria (HOB) for the removal of orthophosphate from surface water as treatment step to prevent cyanobacterial blooms. To be effective as an orthophosphate removal strategy, an efficient transfer of hydrogen to the HOB is essential. A trickling filter was selected for this purpose. Using this system, a removal rate of 11.32 ± 0.43 mg PO4-3-P/L.d was achieved. The HOB biomass, developed on the trickling filter, is composed of 1.25% phosphorus on dry matter, which suggests that the orthophosphate removal principle is based on HOB growth. Cyanobacterial growth assays of the untreated and treated water showed that Synechocystis sp was only able to grow in the untreated water. Orthophosphate was removed to average residual values of 0.008 mg/L. In this proof of principle study, it is shown that HOB are able to remove orthophosphate from water to concentrations that prevent cyanobacterial growth.


Assuntos
Hidrogênio , Fosfatos , Bactérias , Reatores Biológicos , Oxirredução , Fósforo
7.
Bioresour Technol ; 311: 123549, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32451140

RESUMO

In this work, the influence of batch, semi-continuous and continuous mode on biohydrogen production from dark fermentation effluents (DFEs) as substrate and electron distribution was investigated. Results indicated a better H2 production performance was obtained in semi-continuous mode. 50% decanting volume ratio (DVR) and 24 h feeding interval time (FIT) were found to be the best condition. Maximum average H2 production rate (HPR) and H2 yield were obtained of 8.44 mL/h and 1386.22 ± 44.23 mL H2/g TOC, respectively. 37.71% substrate electrons partitioning to hydrogen were detected. For continuous mode, more substrate electrons were diverted toward SMPs with the increasing of HRT due to the fact that longer cell retention, more chances were provided for cell lysis. The bad performance in batch mode ascribed to 56.39% substrate electrons were transferred to cell growth and soluble microbial products (SMPs).


Assuntos
Elétrons , Hidrogênio , Reatores Biológicos , Fermentação , Concentração de Íons de Hidrogênio , Estudos Longitudinais
8.
J Environ Manage ; 268: 110674, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32383647

RESUMO

To avoid hydrogen injection and to enhance the settleability of microbial biomass in biological treatment of nitrate-contaminated drinking water resources, a new method based on granulation of a mixture of hydrogen consumer denitrifiers (HCD) and microalgae is introduced. Decreasing hydraulic retention time (HRT) was applied as the selection pressure in an up-flow photobioreactor to increase the speed of granulation and nitrate removal under autotrophic condition during a 50-day operation. Formation of granules occurred at three phases including granule nucleation, growth of granule, and mature granule, with decreasing the values of ζ-potential from -19 mV to -4 mV. Enhancement of microbial attachment within granule formation could reduce the presence of total suspended solids in the effluent. Developed granules of HCD and microalgae could settle down with velocity of 40 ± 0.6 m/h when reaching the average size of 1.2 mm at day 40. Complete NO3--N removal from drinking water was achieved from the initial stage of granulation until the end of operation at all HRTs of 3 days-5 h. The clear treated water was obtained at the growth phase when the chemical oxygen demand and phosphate were undetectable. Therefore, the application of HCD-microalgae granule is a promising way for nitrate removal from water.


Assuntos
Água Potável , Microalgas , Purificação da Água , Processos Autotróficos , Reatores Biológicos , Desnitrificação , Hidrogênio , Nitratos
9.
Bioresour Technol ; 312: 123570, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32470828

RESUMO

To better clarify the effect of lighting and mixing on the hydrogen production from agricultural waste, experiments under diverse constant and dynamic light intensities and mixing speeds were conducted. Cumulative hydrogen yield, hydrogen production rate, OD660, pH, reducing sugar concentration were monitored. Results showed that mixing had positive effects on high substrate concentration. The interaction between lighting and mixing was drawn. Higher light intensity (7000 Lux) was suitable for hydrogen production under mixing. Higher light intensity with higher mixing speed (150 RPM) showed the highest cumulative hydrogen yield of 78.1 mL/g TS. Different periods of hydrogen production process required distinct lighting and mixing. Combined with Gompertz model, dynamic lighting and mixing strategies were discussed. Dynamic light intensity (4000-7000-4000 Lux) accompanied with dynamic mixing speed (50-150-50 RPM) was the optimal condition for PFHP. Highest hydrogen yield of 84.7 mL/g TS and highest light conversion efficiency of 36.32% were obtained.


Assuntos
Hidrogênio , Iluminação , Agricultura , Fermentação , Concentração de Íons de Hidrogênio
10.
Chemosphere ; 255: 126864, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32402869

RESUMO

This work demonstrates the ability of aqueous phase corona discharge to chemically reduce bromate and chlorate ions, common disinfection byproducts, to bromide and chloride ions, respectively. A high voltage pulse was applied to a needle electrode, submerged in the target solution, to generate highly reactive oxidative and reductive species in a temperature-controlled reactor. Optimal water matrix conditions were sought through changing the solution pH, temperature, and dissolved oxygen concentration. Additionally, several oxidative species scavengers were investigated, including methanol, ethanol, sucrose, and D-sorbitol. Chemical reduction rates were improved at low pH (3.5). The presence of dissolved oxygen significantly reduced the chemical reduction rate, and thus high solution temperature (50 °C) also achieved better chemical reduction. All oxidative species scavengers improved the chemical reduction rate; however, methanol and ethanol were superior as these compounds generate hydrogen bubbles in the presence of plasma, which deoxygenates the solution further improving the chemical reduction rate. The application of this technology to 30 µM bromate and chlorate solutions, under optimal water matrix conditions and with the addition of 72 g/L-COD methanol, achieved greater than 95% removal of the target compounds within 60 min. Increasing the initial concentration of the target compounds to 300 µM required 90 and 150 min to achieve similar chemical reductions for bromate and chlorate, respectively.


Assuntos
Bromatos/química , Cloratos/química , Poluentes Químicos da Água/química , Brometos/química , Cloretos , Cloro , Desinfecção , Hidrogênio , Concentração de Íons de Hidrogênio , Metanol , Oxirredução , Temperatura , Água/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos
11.
Cancer Radiother ; 24(4): 332-334, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32446537

RESUMO

Monte Carlo simulations of γ/fast electron-radiolysis of water show that the in situ formation of H3O+ temporarily renders each "native" isolated spur/track region very acidic. For pulsed (FLASH) irradiation with high dose rate, this early time, transient "acid-spike" response is shown to extend evenly across the entire irradiated volume. Since pH controls many cellular processes, this study highlights the need to consider these spikes of acidity in understanding the fundamental mechanisms underlying FLASH radiotherapy.


Assuntos
Elétrons , Oniocompostos/química , Dosagem Radioterapêutica , Água/química , Hidrogênio/efeitos da radiação , Concentração de Íons de Hidrogênio , Transferência Linear de Energia , Método de Monte Carlo , Neoplasias/radioterapia , Oniocompostos/análise , Radiólise de Impulso
12.
Chem Biol Interact ; 326: 109137, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32442417

RESUMO

In the present study eighteen inhibitors of the hydrolytic enzymes of the endocannabinoid system were investigated for antioxidant activity using lipid peroxidation (LP) method. Among the assayed compounds ten belong to carbamates with phenyl [1,1'-biphenyl]-3-ylcarbamate (6), reported for the first time, and eight are retro-amide derivatives of palmitamine. Interestingly, results indicated that most of the tested compounds have good antioxidant properties. In particular, 1,3-di([1,1'-biphenyl]-3-yl)urea (3) shows IC50 = 26 ± 6 µM comparable to ones obtained for standard antioxidants trolox and quercetin (IC50 = 22 ± 6 µM and 23 ± 6 µM, respectively). Compound 3 was investigated further by means of DFT calculations, to clarify a possible mechanism of the antioxidant action. In order to estimate the capability of 3 to act as radical scavenger the structure was optimized at B3LYP/6-311++G** level and the respective bond dissociation enthalpies were calculated. The calculations in non-polar medium predicted as favorable mechanism a donation of a hydrogen atom to the free radical and formation of N-centered radical, while in polar solvents the mechanism of free radical scavenging by SPLET dominates over HAT H-abstraction. The possible radical scavenging mechanisms of another compound with potent antioxidant properties (IC50 = 53 ± 12 µM), the retro-amide derivative of palmitamine (compound 18), was estimated computationally based on the reaction enthalpies of a model compound (structural analogue to 18). The computations indicated that the most favorable mechanisms are hydrogen atom transfer from the hydroxyl group in meta-position of the benzamide fragment in nonpolar medium, and proton transfer from the hydroxyl group in ortho-position of the benzamide fragment in polar medium.


Assuntos
Compostos de Bifenilo/química , Peroxidação de Lipídeos/efeitos dos fármacos , Ureia/química , Anilidas/química , Antioxidantes/química , Benzamidas/química , Ácidos Graxos/química , Depuradores de Radicais Livres/química , Radicais Livres/química , Hidrogênio/química , Ácidos Palmíticos/química , Solventes/química
13.
Chemosphere ; 251: 126364, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32443231

RESUMO

This study is among the first to systematically study the electrochemical reduction of nitrate on boron-doped diamond (BDD) films with different surface terminations and boron-doping levels. The highest nitrate reduction efficiency was 48% and the highest selectivity in the production of nitrogen gas was 44.5%, which were achieved using a BDD electrode with a hydrogen-terminated surface and a B/C ratio of 1.0%. C-H bonds served as the anchor points for attracting NO3- anions close to the electrode surface, and thus accelerating the formation of NO3-(ads). Compared to oxygen termination, hydrogen-terminated BDD exhibited higher electrochemical reactivity for reducing nitrate, resulting from the formation of shallow acceptor states and small interfacial band bending. The hydrophobicity of the hydrogen-terminated BDD inhibited water electrolysis and the subsequent adsorption of atomic hydrogen, leading to increased selectivity in the production of nitrogen gas. A BDD electrode with a boron-doping level of 1.0% increased the density of acceptor states, thereby enhancing the conductivity and promoting the formation of C-H bonds after the cathodic reduction pretreatment leading to the direct reduction of nitrate.


Assuntos
Boro/química , Técnicas Eletroquímicas , Diamante/química , Doping nos Esportes , Eletrodos , Eletrólise/métodos , Hidrogênio/química , Nitratos , Óxidos de Nitrogênio , Oxirredução , Oxigênio , Água
14.
Sci Total Environ ; 732: 139230, 2020 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-32438165

RESUMO

In the present study the bioconversion of dried household food waste (FORBI) to energy carriers was investigated aiming to its sustainable management and valorization. FORBI was either directly fermented towards ethanol and hydrogen or was previously subjected to extraction with water resulting to a liquid fraction (extract) rich in sugars and a solid residue, which were then fermented separately. Subsequently, the effluents were assessed as substrates for methane production via anaerobic digestion (AD). Mono-cultures and co-cultures of C5 and C6 yeasts were used for the alcoholic fermentation whereas for the production of hydrogen, mixed acidogenic consortia were used. Taking into account the optimum yields of biofuels, the amount of recoverable energy was estimated based for each different approach. The maximum ethanol yield was 0.16 g ethanol per kg of FORBI and it was achieved for separate fermentation of liquid and solid fractions of the waste. The highest hydrogen yield that was observed was 210.44 L ± 4.02 H2/kg TS FORBI for 1% solids loading and supplementation with cellulolytic enzymes. Direct AD of either the whole FORBI or its individual fractions led to lower overall energy recovery, compared to that obtained when fermentation and subsequent AD were applied. The recoverable energy was estimated for the different exploitation approaches of the waste. The maximum achieved recoverable energy was 21.49 ± 0.57 MJ/kg.


Assuntos
Alimentos , Anaerobiose , Biocombustíveis , Reatores Biológicos , Fermentação , Hidrogênio , Metano , Fenômenos Microbiológicos , Eliminação de Resíduos
15.
Bioresour Technol ; 307: 123094, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32249026

RESUMO

Recent advances on biohydrogen production using different types of waste biomass with the implementation of nanomaterials are summarized. Inspired by exceptional physicochemical and catalytic properties of nanomaterials, the present review focuses on several approaches including impact of nanomaterials on cellulosic biohydrogen production, possible pretreatment technology, as well as improved enzyme & sugar production in order to enhance the biohydrogen yield. Particularly, impacts of nanomaterial are elaborated in detail on different pathways of biohydrogen production (e.g. dark fermentation, photo-fermentation and hybrid-fermentation) using variety of waste biomass. Additionally, emphases are made on the feasibility of nanomaterials for making the biohydrogen production process more economical and sustainable and hence to develop advanced techniques for biohydrogen production using waste biomass.


Assuntos
Biocombustíveis , Nanoestruturas , Biomassa , Fermentação , Hidrogênio
16.
Bioresour Technol ; 310: 123426, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32344241

RESUMO

In this work, accelerated start-up of biological hydrogen production system fed with glucose and molasses at 55 °C by regulating pH and COD concentration was investigated in two groups. Then three reactors in each group were compared: controlling pH, controlling pH with COD, and controlling the COD. The reactors in group A presented best hydrogen yield of 1.84 mol H2/mol glucose·day and worked stably at the 8th day. The highest hydrogen yield in group B was 2.13 mol H2/mol molasses·day and steadily at the 11th day. It proved that controlling two key parameters of the inflow pH (8.0) and substrate concentration (4000 mg COD/L) could realize fast start-up of hydrogen production reactor. This study demonstrated that Thermoanaerobacterium sp. strain RBIITD could produce hydrogen and provide a new avenue for biological hydrogen production by dark fermentation using cheap substrate towards a more sustainable and feasible technology.


Assuntos
Thermoanaerobacterium , Reatores Biológicos , Fermentação , Hidrogênio , Concentração de Íons de Hidrogênio , Melaço
17.
Bioresour Technol ; 309: 123297, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32283483

RESUMO

The present study targeted towards the feasibility of various agricultural residues for bio-hythane production by anaerobic digestion (AD) process without pre-treatment. Biochemical methane potential (BMP) analysis was carried out for mixed fruit waste (MFW), mixed vegetable waste (MVW), sugarcane bagasse (SB), rice husk (RH), and wheat straw (WS). The analysis of gas was carried out in gas chromatography with a thermal conductivity detector (GC-TCD). The BMP test results in the study for SB, MFW, and MVW reveal that the average percentage value of bio-hythane production was 53.64%, 43.54%, and 40.92% and that of RH and WS was 16.74% and 29.75%, respectively. The result also shows that agricultural biomass, such as WS and RH produces less % of bio-hythane due to the presence of lignocellulosic components. The main contribution of this study is to highlight the bio-hythane potential with reference to the bio-methane and bio-hydrogen productions from the agricultural residues.


Assuntos
Metano , Saccharum , Anaerobiose , Biocombustíveis , Biomassa , Hidrogênio , Triticum
18.
Bioresour Technol ; 309: 123331, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32283484

RESUMO

Biohydrogen production was evaluated using cassava processing wastewater (CPW) and two microbial consortia (Vir and Gal) from different Brazilian environments. The biohydrogen production was optimized using a Box-Behnken design (T, pH, C/N, and % v/v inoculum). Maximum yields were obtained with hydrolyzed substrate: 4.12 and 3.80 mol H2 / for Vir and Gal, respectively. Similarly, the kinetic parameters µ, k, and q were higher with hydrolyzed CPW in both consortia. The molecular analysis of the consortia through Illumina high-throughput sequencing showed the presence of bacteria from the families Porphyromonadaceae, Clostridiaceae, Ruminococcaceae, and Enterococcaceae. The relative abundance of microbial families varies as fermentation progresses. In both consortia, Clostridiaceae reached the maximum relative abundance in the media between 16 and 24 h, interval in which approximately 90% of the biohydrogen is generated.


Assuntos
Manihot , Águas Residuárias , Reatores Biológicos , Brasil , Fermentação , Hidrogênio , Cinética , Consórcios Microbianos
19.
Bioresour Technol ; 308: 123265, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32272390

RESUMO

This study examined the effect of shear velocity on biohydrogen producing dynamic membrane bioreactor (DMBR) containing 50 µm polyester mesh as supporting material. Increase of shear velocity up to 6.75 m/h enhanced hydrogen production performance as well as biomass retention in both suspended and attached forms, while wash-out was found at a shear velocity of 11.69 m/h. The highest average HPR, HY, suspended biomass, and attached biomass were 26.56 ± 1.49 L/L-d, 1.78 ± 0.10 mol H2/mol glucoseadded, 9.99 ± 0.11 g VSS/L, and 8.82 g VSS/L, respectively, at a shear velocity of 6.75 m/h. Flux balance analysis showed homoacetogenic pathway decreased at the shear velocity of 4.70 m/h with the increase of hydrogen yield based on consumed substrate. The highest copy numbers of Clostridium butyricum was found at the optimum shear velocity. Shear velocity would be a critical operational criteria for continuous biohydrogen production using DMBR.


Assuntos
Reatores Biológicos , Clostridium butyricum , Biomassa , Fermentação , Hidrogênio
20.
PLoS One ; 15(4): e0227582, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32302306

RESUMO

Molecular hydrogen is thought to have an inhibitory effect on oxidative stress, thereby attenuating the onset and progression of various diseases including cardiovascular disease; however, few reports have assessed the preventive effect of constitutive inhalation of hydrogen gas on of vascular remodeling. Here, we investigated the effect of constitutive inhalation of hydrogen gas on vascular neointima formation using a cuff-induced vascular injury mouse model. After constitutive inhalation of compressed hydrogen gas (O2 21%, N2 77.7%, hydrogen 1.3%) or compressed air only (O2 21%, N2 79%) by C57BL/6 mice for 2 weeks from 8 weeks of age in a closed chamber, inflammatory cuff injury was induced by polyethylene cuff placement around the femoral artery under anesthesia, and hydrogen gas administration was continued until sampling of the femoral artery. Neointima formation, accompanied by an increase in cell proliferation, was significantly attenuated in the hydrogen group compared with the control group. NADPH oxidase NOX1 downregulation in response to cuff injury was shown in the hydrogen group, but the expression levels of NADPH oxidase subunits, p40phox and p47phox, did not differ significantly between the hydrogen and control groups. Although the increase in superoxide anion production did not significantly differ between the hydrogen and control groups, DNA damage was decreased as a result of reduction of reactive oxygen species such as hydroxyl radical (⋅OH) and peroxynitrite (ONOO-) in the hydrogen group. These results demonstrate that constitutive inhalation of hydrogen gas attenuates vascular remodeling partly via reduction of oxidative stress, suggesting that constitutive inhalation of hydrogen gas at a safe concentration in the living environment could be an effective strategy for prevention of vascular diseases such as atherosclerosis.


Assuntos
Hidrogênio/administração & dosagem , Isquemia Miocárdica/prevenção & controle , Neointima/prevenção & controle , Remodelação Vascular/efeitos dos fármacos , Lesões do Sistema Vascular/complicações , Administração por Inalação , Animais , Dano ao DNA/efeitos dos fármacos , Modelos Animais de Doenças , Regulação para Baixo/efeitos dos fármacos , Gases/administração & dosagem , Gases/química , Humanos , Radical Hidroxila/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Isquemia Miocárdica/patologia , NADPH Oxidase 1/metabolismo , Neointima/etiologia , Neointima/patologia , Nitrogênio/administração & dosagem , Estresse Oxidativo/efeitos dos fármacos , Oxigênio/administração & dosagem , Ácido Peroxinitroso/metabolismo
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