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1.
Food Chem ; 448: 139185, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-38574715

RESUMO

The impact of hydrogen (H2) producing magnesium (Mg) incorporation into minced beef meat (MBM) on the quality and safety of the product was investigated. The H2-producing Mg (H2-P-Mg)-incorporated MBMs were vacuumed (VP) and stored at 4 °C for 12 days. Other MBMs were vacuumed and gassed with H2 or N2. At the end of storage, the lowest browning index values were for H2 and H2-P-Mg samples. H2- PMg and VP methods generally decreased the counts of mesophilic and psychrotrophic bacteria and yeast molds and restricted the formation of thiobarbituric acid reactive substances and biogenic amines. Heat mapping, PCA, and multivariate analysis methods confirmed chemical analysis results. The volatile compounds were at their highest levels in the control samples at the end of storage, followed by H2, N2, H2-P-Mg, and VP samples. Using the H2-P-Mg method in MBM preparation could protect the quality characteristics and safety of the product during cold storage.


Assuntos
Conservação de Alimentos , Armazenamento de Alimentos , Hidrogênio , Magnésio , Animais , Bovinos , Hidrogênio/metabolismo , Hidrogênio/análise , Magnésio/análise , Magnésio/metabolismo , Conservação de Alimentos/métodos , Temperatura Baixa , Produtos da Carne/análise , Produtos da Carne/microbiologia , Bactérias/metabolismo , Bactérias/isolamento & purificação , Carne Vermelha/análise , Carne Vermelha/microbiologia
2.
BMC Gastroenterol ; 24(1): 143, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38654193

RESUMO

BACKGROUND: Food malabsorption and intolerance is implicated in gastrointestinal symptoms among patients with irritable bowel syndrome (IBS). Key triggers include fructose and fructan. Prior studies examined fructose and fructan malabsorption separately in IBS patients. None have concurrently assessed both within the same patient group. We aimed to investigate the association between fructose and fructan malabsorption in the same patients with IBS using hydrogen breath testing (HBT). METHODS: We retrospectively identified patients with IBS who underwent fructose and fructan HBTs and abstracted their results from the electronic medical record. Fructose and fructan HBTs were performed by administering a 25 g fructose solution or 10 g fructan solution, followed by breath hydrogen readings every 30 min for 3 h. Patients were positive for fructose or fructan malabsorption if breath hydrogen levels exceeded 20 ppm. RESULTS: Of 186 IBS patients, 71 (38.2%) were positive for fructose malabsorption and 91 (48.9%) were positive for fructan malabsorption. Of these patients, 42 (22.6%) were positive for fructose malabsorption and fructan malabsorption. Positive fructose HBT readings were significantly associated with positive fructan HBT readings (p = 0.0283). Patients positive for fructose malabsorption or fructan malabsorption had 1.951 times higher odds of testing positive for the other carbohydrate. CONCLUSIONS: Our results reveal a clinically significant association between fructose malabsorption and fructan malabsorption in patients with IBS. Fructan malabsorption should be assessed in patients with fructose malabsorption, and vice versa. Further studies are required to identify the mechanisms underlying our findings.


Assuntos
Testes Respiratórios , Frutanos , Frutose , Síndrome do Intestino Irritável , Síndromes de Malabsorção , Humanos , Síndrome do Intestino Irritável/metabolismo , Síndrome do Intestino Irritável/complicações , Frutose/metabolismo , Feminino , Masculino , Estudos Retrospectivos , Síndromes de Malabsorção/metabolismo , Síndromes de Malabsorção/etiologia , Síndromes de Malabsorção/complicações , Frutanos/metabolismo , Adulto , Pessoa de Meia-Idade , Hidrogênio/análise , Hidrogênio/metabolismo
3.
Bioresour Technol ; 399: 130632, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38552859

RESUMO

In this study, we investigated the advantages of utilizing natural FeS2 ore in the context of dark fermentative hydrogen production within a fermentation system employing heat-treated anaerobic granular sludge with xylose as the carbon source. The results demonstrated a significant improvement in both hydrogen production and the maximum rate, with increases of 2.58 and 4.2 times, respectively. Moreover, the presence of FeS2 ore led to a reduction in lag time by more than 2-3 h. The enhanced biohydrogen production performance was attributed to factors such as the intracellular NADH/NAD+ ratio, redox-active components of extracellular polymeric substances, secreted flavins, as well as the presence of hydrogenase and nitrogenase. Furthermore, the FeS2 ore served as a direct electron donor and acceptor during biohydrogen production. This study shed light on the underlying mechanisms contributing to the improved performance of biohydrogen production from xylose during dark fermentation through the supplementation of natural FeS2 ore.


Assuntos
Esgotos , Xilose , Fermentação , Temperatura Alta , Hidrogênio/análise
4.
Sci Total Environ ; 926: 171943, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38527546

RESUMO

Monoculture plantations in China, characterized by the continuous cultivation of a single species, pose challenges to timber accumulation and understory biodiversity, raising concerns about sustainability. This study investigated the impact of continuous monoculture plantings of Chinese fir (Cunninghamia lanceolata [Lamb.] Hook.) on soil properties, dissolved organic matter (DOM), and microorganisms over multiple generations. Soil samples from first to fourth-generation plantations were analyzed for basic chemical properties, DOM composition using Fourier transform ion cyclotron resonance mass spectrometry, and microorganisms via high-throughput sequencing. Results revealed a significant decline in nitrate nitrogen content with successive rotations, accompanied by an increase in easily degradable compounds like carbohydrates, aliphatic/proteins, tannins, Carbon, Hydrogen, Oxygen and Nitrogen- (CHON) and Carbon, Hydrogen, Oxygen and Sulfur- (CHOS) containing compounds. However, the recalcitrant compounds, such as lignin and carboxyl-rich alicyclic molecules (CRAMs), condensed aromatics and Carbon, Hydrogen and Oxygen- (CHO) containing compounds decreased. Microorganism diversity, abundance, and structure decreased with successive plantations, affecting the ecological niche breadth of fungal communities. Bacterial communities were strongly influenced by DOM composition, particularly lignin/CRAMs and tannins. Continuous monoculture led to reduced soil nitrate, lignin/CRAMs, and compromised soil quality, altering chemical properties and DOM composition, influencing microbial community assembly. This shift increased easily degraded DOM, accelerating soil carbon and nitrogen cycling, ultimately reducing soil carbon sequestration. From environmental point of view, the study emphasizes the importance of sustainable soil management practices in continuous monoculture systems. Particularly the findings offer valuable insights for addressing challenges associated with monoculture plantations and promoting long-term ecological sustainability.


Assuntos
Cunninghamia , Microbiota , Matéria Orgânica Dissolvida , Nitratos/análise , Lignina/metabolismo , Taninos/análise , Taninos/metabolismo , Solo/química , Compostos Orgânicos/análise , Compostos de Enxofre/metabolismo , Nitrogênio/análise , Carbono/análise , Hidrogênio/análise , Oxigênio/análise
5.
J Environ Manage ; 356: 120611, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38508014

RESUMO

Microalgae represent a promising renewable feedstock for the sustainable production of biohydrogen. Their high growth rates and ability to fix carbon utilizing just sunlight, water, and nutrients make them well-suited for this application. Recent advancements have focused on improving microalgal hydrogen yields and cultivation methods. This review aims to summarize recent developments in microalgal cultivation techniques and genetic engineering strategies for enhanced biohydrogen production. Specific areas of focus include novel microalgal species selection, immobilization methods, integrated hybrid systems, and metabolic engineering. Studies related to microalgal strain selection, cultivation methods, metabolic engineering, and genetic manipulations were compiled and analyzed. Promising microalgal species with high hydrogen production capabilities such as Synechocystis sp., Anabaena variabilis, and Chlamydomonas reinhardtii have been identified. Immobilization techniques like encapsulation in alginate and integration with dark fermentation have led to improved hydrogen yields. Metabolic engineering through modulation of hydrogenase activity and photosynthetic pathways shows potential for enhanced biohydrogen productivity. Considerable progress has been made in developing microalgal systems for biohydrogen. However, challenges around process optimization and scale-up remain. Future work involving metabolic modeling, photobioreactor design, and genetic engineering of electron transfer pathways could help realize the full potential of this renewable technology.


Assuntos
Microalgas , Microalgas/metabolismo , Biocombustíveis , Fermentação , Fotobiorreatores , Hidrogênio/análise , Biomassa
6.
Chemosphere ; 353: 141545, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38430945

RESUMO

This study investigates the enhancement of hydrogen gas-sensing performance by introducing silver (Ag) nanoparticles onto tungsten trioxide (WO3) thin films. Herein, the WO3 thin films are deposited onto SiO2/Si substrates using a sputtering technique and Ag nanoparticles are loaded onto the WO3 surface through a spin coating technique. To evaluate the sensing performance of a hydrogen gas, interdigitated titanium (Ti) electrodes are deposited onto the Ag:WO3 layer. Structural, chemical, and morphological analyses are conducted for both pristine WO3 and Ag:WO3 thin films, followed by the investigation of gas-sensing performance by varying hydrogen gas concentrations from 100 ppm to 300 ppm and operating temperatures between 30 °C and 300 °C. The obtained results demonstrate that Ag:WO3 thin films exhibit a notably enhanced response of 5.08% when exposed to a concentration of 100 ppm of hydrogen gas at room temperature, compared to the pristine WO3 of 3.40%. The fabricated Ag:WO3 sensor exhibits a response time of 3.0 s, a recovery time of 4.5 s, and also demonstrates excellent stability over 45 days period. Finally, with the superior sensitivity and fast response time, the fabricated Ti/Ag:WO3/Ti hydrogen gas sensor test-device can be a potential for improvement of safety from both industrial and environmental perspectives.


Assuntos
Hidrogênio , Nanopartículas Metálicas , Hidrogênio/análise , Temperatura , Dióxido de Silício , Prata/química
7.
Waste Manag ; 179: 163-174, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38479255

RESUMO

Catalytic tar cracking is a promising technique for hot syngas cleaning unit in gasification plants because it can preserve tars chemical energy, so increasing the syngas heating value. The cost associated with catalyst preparation is a key issue, together with its deactivation induced by coke deposition. Iron is a cheap and frequently used catalyst, which can also be found in some industrial wastes. The study aims to assess the catalytic efficiency for tar cracking of two waste-derived materials (red mud and sewage sludge) having high content of iron. The catalysts were supported on spheres of γ-Al2O3, and their efficiency was compared to that of a pure iron catalyst. The role of support was investigated by testing pure red mud, with and without the support. A series of long-term tests using naphthalene as tar model compound were carried out under different values of process temperatures (750 °C-800 °C) and steam concentrations (0 %-7.5 %). The waste derived catalysts showed lower hydrogen yields compared to pure iron catalyst, due to their lower content of iron. On the other hand, the conversion efficiencies of all the tested catalysts resulted rather similar, since the Alkali and Alkaline-Earth Metallic species present on the surface of waste-derived catalyst help in preventing coke deposition. The iron oxidation state appears to play an important role, with reduced iron more active than its oxidised form in the tar cracking reactions. This indicates the importance of tuning steam concentration to keep constant the reduced state of iron while limiting coke deposition.


Assuntos
Coque , Vapor , Hidrogênio/análise , Ferro , Alcatrões/química , Biomassa , Catálise
8.
Environ Sci Pollut Res Int ; 31(17): 24815-24835, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38530525

RESUMO

Recently, nanoparticles have drawn a lot of interest as catalysts to enhance the effectiveness and output of biohydrogen generation processes. This review article provides a comprehensive bibliometric analysis of the significance of nanotechnology in dark fermentative biohydrogen production. The study examines the scientific literature from the database of The Web of Science© while the bibliometric investigation utilized VOSviewer© and Bibliometrix software tools to conduct the analysis. The findings revealed that a total of 232 articles focused on studying dark fermentation for hydrogen production throughout the entire duration. The extracted data was used to analyze publication trends, authorship patterns, and geographic distribution along with types and effects of nanoparticles on the microbial community responsible for dark fermentative biohydrogen production. The findings of this bibliometric analysis provide valuable insights into the advancements and achievements in the utilization of nanoparticles in the dark fermentation process used to produce biohydrogen.


Assuntos
Hidrogênio , Nanotecnologia , Fermentação , Hidrogênio/análise , Biocombustíveis
9.
Environ Res ; 248: 118338, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38316390

RESUMO

The study investigated the influences of pure H2 and O2 introduction, simulating gases produced from the electrokinetic-enhanced bioremediation (EK-Bio), on TCE degradation, and the dynamic changes of the indigenous microbial communities. The dissolved hydrogen (DH) and oxygen (DO) concentrations ranged from 0.2 to 0.7 mg/L and 2.6 to 6.6 mg/L, respectively. The biological analysis was conducted by 16S rRNA sequencing and functional gene analyses. The results showed that the H2 introduction enhanced TCE degradation, causing a 90.4% TCE removal in the first 4 weeks, and 131.1 µM was reduced eventually. Accordingly, cis-dichloroethylene (cis-DCE) was produced as the only product. The following three ways should be responsible for this promoted TCE degradation. Firstly, the high DH rapidly reduced the oxidation-reduction potential (ORP) value to around -500 mV, beneficial to TCE microbial dechlorination. Secondly, the high DH significantly changed the community and promoted the enrichment of TCE anaerobic dechlorinators, such as Sulfuricurvum, Sulfurospirillum, Shewanella, Geobacter, and Desulfitobacterium, and increased the abundance of dechlorination gene pceA. Thirdly, the high DH promoted preferential TCE dechlorination and subsequent sulfate reduction. However, TCE bio-remediation did not occur in a high DO environment due to the reduced aerobic function or lack of functional bacteria or co-metabolic substrate. The competitive dissolved organic carbon (DOC) consumption and unfriendly microbe-microbe interactions also interpreted the non-degradation of TCE in the high DO environment. These results provided evidence for the mechanism of EK-Bio. Providing anaerobic obligate dechlorinators, and aerobic metabolic bacteria around the electrochemical cathodes and anodes, respectively, or co-metabolic substrates to the anode can be feasible methods to promote remediation of TCE-contaminated shallow aquifer under EK-Bio technology.


Assuntos
Tricloroetileno , Biodegradação Ambiental , Tricloroetileno/análise , Tricloroetileno/metabolismo , RNA Ribossômico 16S , Bactérias/metabolismo , Hidrogênio/análise , Hidrogênio/metabolismo , Oxigênio/análise , Oxigênio/metabolismo
10.
Sci Total Environ ; 917: 170489, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38301785

RESUMO

Estuaries receive substantial amounts of terrestrial dissolved organic nitrogen (tDON), which will be transported from the freshwater to the oceanic terminus through vigorous exchange processes. However, the intricate migration and transformation dynamics of tDON during this transportation, particularly at a molecular level, remain constrained. To address this knowledge gap, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used for the analysis of DON molecular composition in the Pearl River Estuary (PRE), a river-dominated estuarine system influenced by intensified anthropogenic activities in southern China. The results showed a pronounced spatial-temporal variation in DON concentration in the study area. At the molecular level, tDON exhibited reduced unsaturation and aromaticity, coupled with an elevated abundance of DON compounds containing one­nitrogen atom (1 N-DON, 53.17 %) and compounds containing carbon, hydrogen, oxygen, nitrogen, and sulfur (CHONS) (27.46 %). It was evident that lignin was depleted while more oxygenated tannin compounds were generated in the freshwater-seawater mixing zone. This transformation is attributed to heightened biological activities, likely influenced by the priming effect of terrestrial nutrient inputs. In summer, the prevailing plume combined with biological activities in the strong mixing area and outer estuary increased the abundance of 3 N-DON molecules and a concurrent rise in the abundance of DON compounds containing only carbon, hydrogen, oxygen, and nitrogen (CHON), DON compounds containing carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus (CHONSP), and CHONS. This trend also underscores the expanding role of marine plankton and microbes in the utilization of DON compounds containing carbon, hydrogen, oxygen, nitrogen, and phosphorus (CHONP). These findings provide details of tDON transformation processes at the molecular level in a river-dominated estuary and underline the estuarine hydrodynamics involved in transporting and altering DON within the estuary.


Assuntos
Matéria Orgânica Dissolvida , Hidrodinâmica , Nitrogênio/análise , Rios , Estuários , Carbono/análise , Oxigênio/análise , Enxofre/análise , Hidrogênio/análise , Fósforo/análise
11.
Anal Methods ; 16(11): 1564-1569, 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38406836

RESUMO

In this comprehensive study, we evaluated the feasibility of using hydrogen instead of helium as a carrier gas in a GC-MS/MS system for pesticide residue analysis, spanning three matrices: pepper, tomato, and zucchini. Initial assessments focused on the ion source's chemical inertness, employing nitrobenzene as a benchmark to monitor the hydrogenation process. A method with a duration of less than 12 minutes was developed, achieving good chromatographic peak resolution attributable to the enhanced chromatographic performance of hydrogen as a carrier gas. The study emphasized the optimization of system parameters, testing various ion source temperatures, detector voltages, and injection volumes. Sensitivity assessments, based on the DG-SANTE criteria, indicated that the majority of compounds were identifiable at a concentration of 5 µg kg-1 (81% in tomato, 84% in pepper and 73% in zucchini). Detailed validation for reproducibility, matrix effects, and linearity across 150 pesticides unveiled generally favorable outcomes, with a notable majority of compounds displaying low matrix effects, satisfactory linearity ranges and good reproducibility with most compounds returning a relative standard deviation (RSD) below 10%. When applied to 15 real samples, the hydrogen-based system's performance was juxtaposed against a helium-based counterpart, revealing that results are very comparable between both systems. This comparative approach highlights hydrogen's potential as a reliable and efficient carrier gas in pesticide residue analysis for routine food control laboratories, overcoming difficulties resulting from the lack of helium supplies.


Assuntos
Resíduos de Praguicidas , Praguicidas , Espectrometria de Massas em Tandem/métodos , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Verduras/química , Praguicidas/análise , Hélio/análise , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/química , Reprodutibilidade dos Testes , Hidrogênio/análise
12.
J Environ Manage ; 351: 119719, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38043306

RESUMO

Landfill leachate properties contain important information and can be a unique indicator for the chemical and biochemical activities in landfills. In the recent decade, more landfills are experiencing elevated temperature, causing an imbalance in the decomposition of solid waste and affecting the properties of the landfill leachate. This study analyzes the properties of leachate from two landfills that were experiencing elevated temperature (ETLFs), samples were collected from both elevated temperature impacted and non-impacted areas in each landfill. The accumulation of volatile fatty acids (VFA) in leachates from elevated temperature impacted areas of both landfill sites revealed that methanogenesis was inhibited by the elevated temperature, which was further confirmed by the more acidic pH, higher H/C elemental ratio, and lower degree of aromaticity of the elevated temperature impacted leachates. Also, carbohydrates depletion indicated possible enhancement of hydrolysis and acidogenesis by elevated temperature, which was supported by compositional comparison of isolated acidic species by negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICRMS) at 21 T derived from both elevated temperature impacted and non-impacted areas in the same landfill site. Furthermore, leachate organics fractionation showed that leachates not impacted by elevated temperature contain less hydrophilic fraction and more humic fraction than elevated temperature-impacted leachates for both ETLFs.


Assuntos
Eliminação de Resíduos , Poluentes Químicos da Água , Eliminação de Resíduos/métodos , Poluentes Químicos da Água/química , Temperatura , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos , Hidrogênio/análise
13.
Environ Res ; 244: 117815, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38048865

RESUMO

Hydrogen has emerged as an alternative energy source to meet the increasing global energy demand, depleting fossil fuels and environmental issues resulting from fossil fuel consumption. Microalgae-based biomass is gaining attention as a potential source of hydrogen production due to its green energy carrier properties, high energy content, and carbon-free combustion. This review examines the hydrogen production process from microalgae, including the microalgae cultivation technological process for biomass production, and the three main routes of biomass-to-hydrogen production: thermochemical conversion, photo biological conversion, and electrochemical conversion. The current progress of technological options in the three main routes is presented, with the various strains of microalgae and operating conditions of the processes. Furthermore, the economic and environmental perspectives of biomass-to-hydrogen from microalgae are evaluated, and critical operational parameters are used to assess the feasibility of scaling up biohydrogen production for commercial industrial-scale applications. The key finding is the thermochemical conversion process is the most feasible process for biohydrogen production, compared to the pyrolysis process. In the photobiological and electrochemical process, pure hydrogen can be achieved, but further process development is required to enhance the production yield. In addition, the high production cost is the main challenge in biohydrogen production. The cost of biohydrogen production for direct bio photolysis it cost around $7.24 kg-1; for indirect bio photolysis it costs around $7.54 kg-1 and for fermentation, it costs around $7.61 kg-1. Therefore, comprehensive studies and efforts are required to make biohydrogen production from microalgae applications more economical in the future.


Assuntos
Microalgas , Indicadores Ambientais , Biocombustíveis/análise , Fermentação , Hidrogênio/análise , Combustíveis Fósseis , Biomassa
14.
Zhonghua Nei Ke Za Zhi ; 62(11): 1335-1340, 2023 Nov 01.
Artigo em Chinês | MEDLINE | ID: mdl-37935501

RESUMO

Objective: To investigate the diagnostic value of a single hydrogen-methane breath test (SHMBT) for small intestinal bacterial overgrowth (SIBO). Method: The current investigation was a cross-sectional study. Questionnaires and SHMBTs were administered to 162 patients with gastrointestinal symptoms (case group) and 69 healthy volunteers (control group). Differences in SHMBT results between the two groups were assessed,and cut-off values of CH4 (methane) and H2 (hydrogen) were analyzed via receiver operating characteristic (ROC) curves. Lastly,archived SHMBT data from 2 655 patients with gastrointestinal symptoms (validation set) were used to evaluate the diagnostic value of the SHMBT with respect to SIBO. The Chi-square test,the Mann-Whitney U test,Spearman's Rank correlation analysis,and the Z test were used for statistical analysis. Results: Based on the international recommended diagnostic criteria for SIBO,which are fasting CH4 ≥10 ppm (parts per million) or H2 ≥20 ppm,the SHMBT-positive rate in the case group was significantly higher than that of control group (35.2% vs. 21.7%, χ2=4.08, P=0.043). Levels of CH4 and H2 were higher in the case group than in the control group [CH4: 3(2,7) vs. 3(1,3) ppm, H2: 11(4,22) vs. 10(5,15) ppm],and the difference in CH4 levels was statistically significant (Z=6.22,P=0.001). ROC curves were generated based on whether the subjects had gastrointestinal symptoms. The areas under the ROC curves were 0.633 for CH4 alone,0.531 for H2 alone, and 0.620 for CH4 combined with H2. The cut-off values were fasting CH4≥4 ppm,fasting H2≥13 ppm,and fasting CH4 ≥5 ppm (or CH4≥4 ppm and H2≥24 ppm),respectively. Measuring CH4 alone and CH4 combined with H2 was effective for determining the presence of gastrointestinal symptoms (P<0.05). When CH4 alone or CH4 combined with H2 were used as diagnostic indicators of SIBO, the respective SHMBT-positive rates in the validation set were 34.2% and 30.4%. These rates did not significantly differ from the SIBO-positive rate of 32.0% obtained via the international recommended diagnostic criteria (P>0.05). The specificity of CH4 alone was 79.9%,and the accuracy of CH4 alone was 68.8%. The specificity of CH4 combined with H2 was 85.0%,and the accuracy of CH4 combined with H2 was 71.7%. Conclusion: Rapid one-time determination of CH4 and H2 in exhaled breath may a viable diagnostic method for SIBO, and using CH4 combined with H2 (i.e.,fasting CH4≥5 ppm, or CH4 ≥4 ppm and H2 ≥24 ppm) as cutoff values may be feasible.


Assuntos
Gastroenteropatias , Metano , Humanos , Metano/análise , Estudos Transversais , Intestino Delgado/microbiologia , Bactérias , Testes Respiratórios/métodos , Hidrogênio/análise
15.
Environ Sci Pollut Res Int ; 30(52): 112631-112643, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37837588

RESUMO

Application of municipal solid and wood waste, as dominant sources of biomass, could be a promising alternative for producing energy from renewables via thermochemical gasification technology. In this paper, a study of thermogravimetric analysis (TGA) and excurrent gas composition produced by the municipal solid waste (MSW) and wood biomass gasification is presented. Thermogravimetric and heat flow curves for waste samples were performed at the temperature interval of 20-890 °C with a heating rate of 10 °C min-1 under a nitrogen atmosphere. According to thermal analysis data, differential scanning calorimetry (DSC) curves, the degradation stages of waste samples was determined, which correspond to the mono- or bimodal evolution of volatile compounds and the degradation of the resulting carbon residue. The gasification experiments were conducted in a high-pressure quartz reactor at temperatures of 850, 900, and 950 °C, using steam (0.3 g/min) and argon (2 dm3/min) as the gasifying agents. To ascertain the syngas composition, gas chromatography was employed in conjunction with a thermal conductivity detector. Both types of biomass showed remarkably similar syngas compositions. The highest concentration of hydrogen-rich gases was recorded at 950 °C for wood biomass, with 42.9 vol% and 25.2 vol% for hydrogen (H2) and carbon monoxide (CO), and for MSW, with an average 44.2 vol% and 18 vol% for H2 and CO. Higher temperatures improved the syngas composition by promoting endothermic gasification reactions, increasing hydrogen yield while decreasing tar and solid yields. This research helped to comprehend the evolution of the gasification process and the relationship between increased H2 and CO production as the gasification temperature increased.


Assuntos
Eliminação de Resíduos , Resíduos Sólidos , Resíduos Sólidos/análise , Eliminação de Resíduos/métodos , Biomassa , Madeira/química , Gases/análise , Vapor , Hidrogênio/análise
16.
Environ Sci Pollut Res Int ; 30(46): 102129-102157, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37684507

RESUMO

Hydrogen production from biological processes has been hailed as a promising strategy for generating sustainable energy. Fermentative hydrogen production processes such as dark and photofermentation are considered more sustainable and economical than other biological methods such as biophotolysis. However, these methods have constraints such as low hydrogen yield and conversion efficiency, so practical implementations still need to be made. The present review provides an assessment and feasibility of producing biohydrogen through dark and photofermentation techniques utilizing various lignocellulosic biomass wastes as substrates. Furthermore, this review includes information about the strategies to increase the productivity rate of biohydrogen in an eco-friendly and sustainable manner, like integration of dark and photofermentation techniques, pretreatment of biomass, genetic modification of microorganisms, and application of nanoadditives.


Assuntos
Biocombustíveis , Hidrogênio , Biomassa , Fermentação , Hidrogênio/análise , Redes e Vias Metabólicas
17.
J Environ Manage ; 345: 118773, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37619386

RESUMO

The necessity of achieving climate goals has become more pressing during the past two years. Discussions on implementing and achieving these goals have taken place in addition to the tightening of the climate targets and the desire for net-zero attainment by as early as 2050. Along with the capacity of biomass to supply the energy needs of society today being quite significant, hydrogen may be the best choice to replace fossil fuels as a clean energy source. Therefore, this study presents a high-level overview of the bio-hydrogen technical pathways, as well as socioeconomic and ecological aspects of bio-hydrogen, and an analysis of the global hydrogen development. A focus on Egypt, as a prominent spot on the global energy map, could instruct other emerging countries and help policymakers of the national hydrogen agenda to prioritize developing a new legal framework to regulate hydrogen production projects, offering financial incentives to energy-intensive companies to switch to using green hydrogen, and providing transparency and certainty regarding future hydrogen demand possibilities.


Assuntos
Carbono , Hidrogênio , Hidrogênio/análise , Egito , Fontes Geradoras de Energia , Combustíveis Fósseis
18.
Bioresour Technol ; 386: 129519, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37468010

RESUMO

The transition to renewable energy sources is crucial to ensure a sustainable future. Although the sugar and ethanol industries benefit from this transition, there are untapped opportunities to utilize the waste generated from the sugar and ethanol process chains through two-stage anaerobic digestion (TSAD). This review comprehensively discusses the utilization of various sugarcane-based industrial wastes by TSAD for sequential biohydrogen and methane production. Factors influencing TSAD process performance, including pH, temperature, hydraulic retention time, volatile fatty acids and alkalinity, nutrient imbalance, microbial population, and inhibitors, were discussed in detail. The potential of TSAD to reduce emissions of greenhouse gases is demonstrated. Recent findings, implications, and promising future research related to TSAD, including the integration of meta-omics approaches, gene manipulation and bioaugmentation, and application of artificial intelligence, are highlighted. The review can serve as important literature for the implementation, improvement, and advancements in TSAD research.


Assuntos
Resíduos Industriais , Saccharum , Etanol , Açúcares , Inteligência Artificial , Hidrogênio/análise , Biocombustíveis , Metano , Anaerobiose , Reatores Biológicos
19.
Chemosphere ; 338: 139526, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37459926

RESUMO

The depletion of fossil fuel sources and increase in energy demands have increased the need for a sustainable alternative energy source. The ability to produce hydrogen from microalgae is generating a lot of attention in both academia and industry. Due to complex production procedures, the commercial production of microalgal biohydrogen is not yet practical. Developing the most optimum microalgal hydrogen production process is also very laborious and expensive as proven from the experimental measurement. Therefore, this research project intended to analyse the random time series dataset collected during microalgal hydrogen productions while using various low thermally pre-treated palm kernel expeller (PKE) waste via machine learning (ML) approach. The analysis of collected dataset allowed the derivation of an enhanced kinetic model based on the Gompertz model amidst the dark fermentative hydrogen production that integrated thermal pre-treatment duration as a function within the model. The optimum microalgal hydrogen production attained with the enhanced kinetic model was 387.1 mL/g microalgae after 6 days with 1 h thermally pre-treated PKE waste at 90 °C. The enhanced model also had better accuracy (R2 = 0.9556) and net energy ratio (NER) value (0.71) than previous studies. Finally, the NER could be further improved to 0.91 when the microalgal culture was reused, heralding the potential application of ML in optimizing the microalgal hydrogen production process.


Assuntos
Microalgas , Fermentação , Hidrogênio/análise , Combustíveis Fósseis , Biocombustíveis , Biomassa
20.
Int J Cosmet Sci ; 45(6): 749-760, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37461190

RESUMO

Extracts from rosemary (Salvia Rosmarinus) are analysed for their phytochemistry using LC-MS and the phytochemistry identified. The same extracts were tested for their efficacy to act as antioxidants by both hydrogen-atom transfer (ORAC) and single electron transfer (FRAP). A correlation analysis was performed to identify the key phytochemistry responsible for antioxidant efficacy. The top performing extracts were then tested in a peptide model and in hair with the presence of UV to measure ability to protect against UV-induced peptide and protein damage. Polyphenols (e.g. rosmarinic acid, glycosides of selgin) and abietane diterpenes (e.g. carnosic acid) in rosemary were identified as the principal compounds which enables the extracts to protect hair from UV. OBJECTIVE: The objective of this work was to correlate the phytochemistry of rosemary (Salvia rosmarinus), a botanical with known antioxidant properties, to a UV protection benefit in hair. These data will give insights into mechanisms of UV damage, the ROS formed and their reactivity. METHODS: LC-MS was used to compare the compounds in 10 commercial extracts of rosemary. ORAC (oxygen radical antioxidant capacity) and FRAP (ferric reducing antioxidant power) were used to measure the antioxidant capacity of the rosemary extracts. The ORAC assay measures ability of an antioxidant to react with a peroxyl radical via hydrogen atom extraction and FRAP measures electron transfer through reduction of ferric iron (Fe3+ ) to ferrous iron (Fe2+ ) by antioxidants present in the samples. Correlation of extract composition with antioxidant measures was performed using principal component analysis. Selected extracts were assessed for their ability to protect hair from UV damage in a model peptide system and on hair. In addition, the same methods were used to test rosmarinic acid and carnosic acid, key phytochemistries in the rosemary extracts. The model system was a peptide and its decomposition on exposure to UV was monitored by LC-MS in the absence and presence of the rosemary extracts. Hair degradation in the presence of UV was measured by exposure of UV in an Atlas weatherometer followed by extraction of degraded protein in water. A fragment of the S100A3 protein was used as a marker of UV damage (m/z = 1278) and quantified via LC-MS. RESULTS: Ten rosemary extracts were assessed for antioxidant performance and correlated with their compositions. The phytochemistry in each extract varied widely with a total of 33 individual compounds identified. The differences were most likely driven by the solvent and extraction method used by the supplier with extracts varying in the proportion of polar or non-polar compounds. This did influence their reactivity in the ORAC and FRAP assays and their efficacy in preventing protein damage. Two of the key compounds identified were rosmarinic acid and carnosic acid, with rosmarinic acid dominating in extracts with mainly polar compounds and carnosic acid dominating in extracts with mainly nonpolar compounds. Extracts with higher rosmarinic acid correlated with ORAC and FRAP scores, with UV protection on hair and in the peptide model system. The extracts chosen for hair experiments showed hair protection. UV protection was also measured for rosmarinic and carnosic acid. CONCLUSIONS: Despite the variation in the profile of phytochemistries in the 10 rosemary extracts, likely driven by the chosen extraction method, all rosemary extracts had antioxidant activity measured. This study suggests that the polyphenols (e.g. rosmarinic acid, glycosides of selgin) and abietane diterpenes (e.g. carnosic acid) are the principal compounds which enables the extracts to protect hair from UV.


INTRODUCTION: Les extraits de romarin (Salvia Rosmarinus) sont analysés par LC-MS pour établir et identifier leur profil phytochimique. Les mêmes extraits ont été testés pour leur efficacité à agir comme antioxydants à la fois par transfert d'atome d'hydrogène (ORAC) et par transfert d'électrons uniques (FRAP). Une analyse de corrélation a été réalisée pour identifier les propriétés phytochimiques clés responsables de l'efficacité antioxydante. Les extraits les plus performants ont ensuite été testés dans un modèle peptidique et sur les cheveux en présences d'UV pour mesurer la capacité à protéger contre les dommages induits par les UV su les peptides et protéines. Les polyphénols (par ex. acide rosmarinique, glycosides de selgin) et les diterpènes d'abiétine (par ex. acide carnosique) dans le romarin ont été identifiés comme les principaux composés permettant aux extraits de protéger les cheveux des UV. OBJECTIF: L'objectif de ce travail était de mettre en corrélation la phytochimie du romarin (Salvia rosmarinus), une plante aux propriétés antioxydantes connues, et les bénéfices d'une protection contre les UV dans les cheveux. Ces données fourniront des informations sur les mécanismes des dommages causés par les UV, la formation du ROS et leur réactivité. MÉTHODES: La LC-MS a été utilisée pour comparer les composés de 10 extraits commerciaux de romarin. L'ORAC (Oxygen Radical Antioxidant Capacity/Capacité d'absorption des radicaux d'oxygène) et la FRAP (Ferric Reduction Antioxidant Power/Pouvoir antioxydant de réduction ferrique) ont été utilisés pour mesurer la capacité antioxydante des extraits de romarin. Le dosage ORAC mesure la capacité d'un antioxydant à réagir avec un radical peroxyl par extraction d'atome d'hydrogène et la FRAP mesure le transfert d'électrons par réduction du fer ferrique (Fe3+ ) en fer ferreux (Fe2+ ) par les antioxydants présents dans les échantillons. La corrélation entre la composition de l'extrait et les mesures des antioxydants a été effectuée en analysant les composants principaux. Les extraits sélectionnés ont été évalués pour leur capacité à protéger les cheveux des dommages causés par les UV dans un modèle de système peptidique et sur les cheveux. En outre, les mêmes méthodes ont été utilisées pour tester l'acide rosmarinique et l'acide carnosique, principales caractéristiques phytochimiques dans les extraits de romarin. Le système modèle était un peptide et sa décomposition à l'exposition aux UV a été suivie par LC-MS en l'absence et en présence des extraits de romarin. La dégradation des cheveux en présence d'UV a été mesurée par l'exposition aux UV dans un indicateur de désagrégation Atlas suivi de l'extraction de protéines dégradées dans l'eau. Un fragment de la protéine S100A3 a été utilisé comme marqueur de dommage UV (m/z = 1278) et quantifié par LC-MS. RÉSULTATS: Dix extraits de romarin ont été évalués en termes de performance antioxydante et mis en corrélation avec leurs compositions. La phytochimie de chaque extrait variait considérablement, avec un total de 33 composés individuels identifiés. Les différences étaient très probablement dues à la méthode du solvant et de l'extraction utilisée par le fournisseur avec des extraits variant dans la proportion de composés polaires ou non polaires. Cela a effectivement influencé leur réactivité dans les dosages ORAC et FRAP et leur efficacité dans la prévention des dommages protéiques. Deux des composés clés identifiés étaient l'acide rosmarinique et l'acide carnosique, l'acide rosmarinique dominant dans les extraits contenant principalement des composés polaires et l'acide carnosique dominant dans les extraits contenant principalement des composés non polaires. Les extraits avec un taux d'acide rosmarinique plus élevé étaient mis en corrélation avec les scores ORAC et FRAP, avec une protection UV sur les cheveux et dans le système de modèle peptidique. Les extraits choisis pour les expériences sur les cheveux ont montré une protection des cheveux. La protection contre les UV a également été mesurée pour l'acide rosmarinique et l'acide carnosique. CONCLUSIONS: Malgré la variation des profils phytochimiques dans les dix extraits de romarin, probablement induite par la méthode d'extraction choisie, l'activité antioxydante de tous les extraits de romarin a été mesurée. Les polyphénols (par ex. acide rosmarinique, glycosides de selgin) et les diterpènes d'abiétane (par ex. acide carnosique) dans le romarin ont été identifiés comme les principaux composés permettant aux extraits de protéger les cheveux contre les UV.


Assuntos
Rosmarinus , Salvia , Antioxidantes/farmacologia , Abietanos/análise , Abietanos/química , Abietanos/farmacologia , Rosmarinus/química , Polifenóis , Glicosídeos , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Ferro , Peptídeos , Hidrogênio/análise
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