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1.
Helicobacter ; 29(4): e13109, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38951739

RESUMEN

BACKGROUND: Integrin-linked kinase (ILK) is crucial in solid tumors by regulating the Hippo-Yes-associated protein 1 (YAP) pathway. This study aimed to uncover how Helicobacter pylori influences ILK levels and its role in regulating YAP during H. pylori-induced gastric cancer. MATERIALS AND METHODS: GES-1 cells with stable Ilk knockdown and overexpression and a mouse carcinogenesis model for H. pylori infection were constructed. And ILK, the phosphorylated mammalian STE20-like protein kinase 1 (MST1), large tumor suppressor 1 (LATS1; S909, T1079), and YAP (S109, S127) were detected in cells, and mice by western blotting, as well as fluorescence intensity of YAP were assayed by immunofluorescence. YAP downstream genes Igfbp4 and Ctgf, the pathological changes and tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), interleukin-1beta (IL-1ß), and nitric oxide (NO) levels in mice gastric tissues were detected by real-time PCR, H&E, and ELISA assays. RESULTS: In this study, stable Ilk knockdown cells exhibited significantly higher phosphorylated levels of MST1, LATS1, and YAP, as well as increased YAP in the nuclei of GES-1 cells. Conversely, cells with Ilk overexpression showed opposite results. H. pylori infection led to decreased ILK levels in gastric epithelial cells but increased ILK levels in gastric cancer cell lines (MGC803, SGC7901) and gastric cancer tissues in mice. Treatment with the ILK inhibitor OST-T315 elevated the phosphorylated MST, LATS1, and YAP levels, and inhibited the mRNA levels of Igfbp4 and Ctgf at 44, 48 week-aged mice. OST-T315 also reduced the release of TNF-α, IL-6, IL-1ß, and NO, as well as the progression of gastric cancer caused by H. pylori and N-Nitroso-N-methylurea (NMU) treatment. CONCLUSION: Upon initiation of gastric tumorigenesis signals, H. pylori increases ILK levels and suppresses Hippo signaling, thereby promoting YAP activation and gastric cancer progression. ILK can serve as a potential prevention target to impede H. pylori-induced gastric cancer.


Asunto(s)
Infecciones por Helicobacter , Helicobacter pylori , Proteínas Serina-Treonina Quinasas , Neoplasias Gástricas , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Animales , Neoplasias Gástricas/microbiología , Neoplasias Gástricas/patología , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/genética , Infecciones por Helicobacter/microbiología , Infecciones por Helicobacter/patología , Ratones , Humanos , Modelos Animales de Enfermedad , Línea Celular , Masculino
2.
Chem Commun (Camb) ; 60(45): 5868-5871, 2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38756077

RESUMEN

Platelike carbon-encapsulated nickel nanocrystals (Ni@C) were engineered as a high-performance electrocatalyst for the conversion of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). This electrocatalyst demonstrated remarkable electrocatalytic performance in oxidizing HMF at a low potential, achieving 100% HMF conversion, 97.7% FDCA yield, and 97.4% Faraday efficiency (FE).

3.
Chem Commun (Camb) ; 60(31): 4214-4217, 2024 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-38525808

RESUMEN

CuO-Ni(OH)2 heterostructure nanosheets were designed for efficient electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furanedioic acid (FDCA). The CuO-Ni(OH)2 nanosheets exhibited impressive performance, achieving 100% HMF conversion, 99.8% FDCA yield, and 98.4% faradaic efficiency.

4.
Sci Total Environ ; 921: 171041, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38369162

RESUMEN

The vertical groundwater circulation well (GCW) is a commonly used technique in contaminated sites to remove secondary contaminants from low permeable zones. Early GCW studies often used simple subsurface hydraulic properties, such as anisotropic homogeneous aquifers or low conductivity lens/blocks, to mimic the complex subsurface heterogeneity. Although studies based on simplified representations of aquifer heterogeneity provide straightforward flow and transport information for engineering design of a GCW, they may over- or under-estimate contaminant fate and transport in the field. The objective of this study is to identify key heterogeneity factors that control the capture zone extension and to examine the extent to which the accuracy of estimated heterogeneity spatial distributions influences the prediction of remedial reagent transport. To achieve these objectives, we utilized Monte Carlo simulation to investigate the extension of the circulation zone in heterogeneous aquifers and to identify the key factors that contribute most to the variability of the circulation zone. Three commonly used geostatistical approaches (equivalent homogeneous, kriging, and highly parameterized methods) were employed to estimate the spatial distributions of key factors. The reliabilities of these estimated fields were evaluated through their remedial reagent transport predictability. The key factor analysis revealed that the mean porosity value, the variance of lnK, and the correlation length of lnK profoundly influence the lateral expansion of the capture zone. Neglecting the aquifer hydraulic conductivity heterogeneity underestimates the extension of the circulation zone and the spread of remedial reagent. Additionally, utilizing a highly parameterized approach to estimate the high-resolution K field can accurately reproduce the key remedial reagent distributions. The concentration arrival time and peak concentration are significantly improved compared to those predictions based on the equivalent homogeneous and kriged K fields.

5.
Plant Sci ; 340: 111963, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38103698

RESUMEN

Cell deformation often occurs during sample preparation and imaging with scanning electron microscope (SEM), especially with delicate samples, which influences the accuracy of the results. Here we investigate the influence of several preparation methods on cell deformation, using water content and tissue hardness as indicators to classify "delicate" samples of plant species. The degree of deformation in samples resulting from five preparation methods was measured at the tissue and single-cell levels, revealing that a cryo- and methanol-fixation produced lower degrees of tissue dimension deformation and better preservation of cell shape for delicate samples, while for harder tissues, other preparation methods for a dehydrated specimen are also suitable. Stability and image quality of delicate samples could be improved with the application of a cryo-protectant combined with a lower cryo-stage temperature, e.g. - 30 °C. We show that the sample stability under the beam was improved by combining larger sample size and cryo-stage application. Furthermore, the influence of adaxial and abaxial tissue surfaces, the accelerating voltage, and sputter coating time on sample stability and image quality was evaluated. Our study is valuable for artifact reduction and easy application of SEM.


Asunto(s)
Plantas , Agua , Microscopía Electrónica de Rastreo , Temperatura
6.
Chem Commun (Camb) ; 59(54): 8440-8443, 2023 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-37337758

RESUMEN

A Mn-doped Ni2P electrocatalyst with a unique microstructure of nanocrystal-decorated amorphous nanosheets was, for the first time, reported for the electrooxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). This electrocatalyst demonstrated superior HMF electrooxidation performance with 100% HMF conversion, 98.0% FDCA yield, and 97.8% Faraday efficiency.

7.
Chemistry ; 29(42): e202300973, 2023 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-37100743

RESUMEN

Electrooxidation of 5-hydroxymethylfural (HMF) into 2,5-furandicarboxylicacid (FDCA) has been regarded as a promising sustainable approach to achieve value-added chemicals. However, it is still impeded by the unsatisfactory performance of electrocatalysts. Here, Cu2 P7 -CoP heterostructure nanosheets were reported to enable powerful HMF electrooxidation. The Cu2 P7 -CoP heterostructure nanosheets were fabricated by microwave-assisted deep eutectic solvent (DES) approach, along with subsequent phosphiding. The Cu2 P7 -CoP heterostructure nanosheets enabled a superb 100 % HMF conversion at 1.43 V (vs. RHE) with 98.8 % FDCA yield and 98 % Faradaic efficiency (FE), demonstrating its promising application in HMF electrooxidation. X-ray photoelectron spectroscopy (XPS) analysis, open-circuit potential (OCP) approach and density functional theory (DFT) calculation uncovered that the electron transfer and redistribution between Cu2 P7 and CoP improved the adsorption capacity of HMF and modulated the catalytic performance. This study not only offered a powerful electrocatalyst for HMF electrooxidation, but also provided a conceptually new strategy for the heterostructure catalyst design.

8.
Ecotoxicology ; 32(1): 57-72, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36567403

RESUMEN

The widespread spread of antibiotic resistance genes (ARGs) in hyporheic zone (HZ) has become an emerging environmental problem due to their potentially harmful nature. In this research, three different oxygen treatment systems were set up to study the effects of oxygen changes on the abundance of ARGs in the HZ. In addition, the effects of temperature and salinity on ARGs were investigated under aerobic and anaerobic systems, respectively. The bacterial community composition of sediment samples and the relationship with ARGs were analyzed. The explanation ratio and causality of the driving factors affecting ARGs were analyzed using variation partitioning analysis (VPA) and structural equation model (SEM). The relative abundance of ARGs and mobile genetic elements (MGEs) in the anaerobic system increased significantly, which was higher than that in the aerobic system and the aerobic-anaerobic interaction system. The experiment of salinity and temperature also further proved this result. There were many bacterial communities that affected tetracycline and sulfonamide ARGs in sediments, and these host bacteria are mainly concentrated in Proteobacteria, Firmicutes and Bacteroidetes. VPA and SEM further revealed that the abundance of ARGs was mainly influenced by changes in bacterial communities and oxygen conditions, and horizontal gene transfer (HGT) of MGEs also had a positive effect on the spread of ARGs. Those findings suggest that complex oxygen conditions in the HZ alter bacterial communities and promote MGEs-mediated horizontal transfer, which together lead to the spread of ARGs. This study has value as a reference for formulating effective strategies to minimize the propagation of ARGs in underground environment.


Asunto(s)
Antibacterianos , Genes Bacterianos , Antibacterianos/farmacología , Bacterias/genética , Farmacorresistencia Microbiana/genética , Sulfanilamida
9.
BMC Genomics ; 23(1): 842, 2022 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-36539699

RESUMEN

BACKGROUND: Organisms in the wild can acquire disease- and stress-resistance traits that outstrip the programs endogenous to humans. Finding the molecular basis of such natural resistance characters is a key goal of evolutionary genetics. Standard statistical-genetic methods toward this end can perform poorly in organismal systems that lack high rates of meiotic recombination, like Caenorhabditis worms. RESULTS: Here we discovered unique ER stress resistance in a wild Kenyan C. elegans isolate, which in inter-strain crosses was passed by hermaphrodite mothers to hybrid offspring. We developed an unbiased version of the reciprocal hemizygosity test, RH-seq, to explore the genetics of this parent-of-origin-dependent phenotype. Among top-scoring gene candidates from a partial-coverage RH-seq screen, we focused on the neuronally-expressed, cuticlin-like gene cutl-24 for validation. In gene-disruption and controlled crossing experiments, we found that cutl-24 was required in Kenyan hermaphrodite mothers for ER stress tolerance in their inter-strain hybrid offspring; cutl-24 was also a contributor to the trait in purebred backgrounds. CONCLUSIONS: These data establish the Kenyan strain allele of cutl-24 as a determinant of a natural stress-resistant state, and they set a precedent for the dissection of natural trait diversity in invertebrate animals without the need for a panel of meiotic recombinants.


Asunto(s)
Proteínas de Caenorhabditis elegans , Caenorhabditis , Humanos , Animales , Caenorhabditis elegans/genética , Kenia , Fenotipo , Proteínas de Caenorhabditis elegans/genética
10.
Cell Death Discov ; 8(1): 372, 2022 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-36002460

RESUMEN

The phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway plays an essential role in glucose metabolism, promoting glycolysis and resisting gluconeogenesis. PI3K/AKT signaling can directly alter glucose metabolism by phosphorylating several metabolic enzymes or regulators of nutrient transport. It can indirectly promote sustained aerobic glycolysis by increasing glucose transporters and glycolytic enzymes, which are mediated by downstream transcription factors. E3 ubiquitin ligase RING-finger proteins are mediators of protein post-translational modifications and include the cullin-RING ligase complexes, the tumor necrosis factor receptor-associated family, the tripartite motif family and etc. Some members of the RING family play critical roles in regulating cell signaling and are involved in the development and progression of various metabolic diseases, such as cancer, diabetes, and dyslipidemia. And with the progression of modern research, as a negative or active regulator, the RING-finger adaptor has been found to play an indispensable role in PI3K/AKT signaling. However, no reviews have comprehensively clarified the role of RING-finger E3 ligases in PI3K/AKT-mediated glucose metabolism. Therefore, in this review, we focus on the regulation and function of RING ligases in PI3K/AKT-mediated glucose metabolism to establish new insights into the prevention and treatment of metabolic diseases.

11.
Front Chem ; 10: 910305, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35860633

RESUMEN

Energy storage film is one of the most important energy storage materials, while the performance of commercial energy storage films currently cannot meet the growing industrial requirements. Hence, this work presents a h-BN/PVDF/h-BN sandwich composite structure film prepared by laminating a large area of ultrathin hexagonal boron nitride (h-BN) and polyvinylidene fluoride (PVDF), the existence of which was confirmed by using an optical microscope and elemental composition analysis based on scanning electron microscopy and X-ray diffraction. This film has an ultrahigh dielectric strength of 464.7 kV/mm and a discharged energy density of up to 19.256 J/cm3, which is much larger than the commercial energy storage film biaxially oriented polypropylene (BOPP) (<2.5 J/cm3). Although the thickness of the h-BN film is only 70 nm compared with that of PVDF (about 12 µm), the dielectric strength of the sandwich-structured film presents a great increase. It is because of the excellent insulation performance of the h-BN film that helps to resist the electron injection and migration under high electric field, and then suppress the formation and growth of the breakdown path, leading to an improvement of the charge-discharge efficiency.

12.
Exp Ther Med ; 23(6): 369, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35495592

RESUMEN

Spironolactone improves cardiac structure, function and prognosis in patients with heart failure and delays the progression of cardiac fibrosis. However, the exact underlying mechanism of this process remains to be elucidated. The present study therefore aimed to explore the protective effect and underlying mechanism of the aldosterone receptor antagonist, spironolactone, on myocardial fibrosis in mice with experimental autoimmune myocarditis (EAM). The EAM model was induced in BALB/c mice via immunization with murine cardiac α-myosin heavy chain sequence polypeptides. The cardiac function of the mice was assessed using echocardiography and the levels of inflammatory cytokines were quantified using ELISA. E26 transformation-specific sequence-1 (Ets-1) expression was knocked down using lentivirus-mediated small interference RNA. Total collagen deposition was assessed using Masson's trichrome and Ets-1, TGF-ß1, Smad2/3, collagen I and III protein expression levels were detected using immunohistochemistry and western blotting. MMP-2 and MMP-9 mRNA expression levels and activity was determined using reverse transcription-quantitative PCR and gelatin zymography, respectively. The results of the present study demonstrated that spironolactone significantly improved myocardium hypertrophy, diastolic cardiac function and decreased myocardial inflammation and collagen deposition induced by EAM. Spironolactone treatment significantly inhibited Ets-1 and smad2/3 phosphorylation. In addition, inhibition of Ets-1 reduced the expression and activity of MMP-2 and MMP-9 and decreased cardiac fibrosis in EAM mice. The results indicated that the improvement of myocardial fibrosis by spironolactone may be associated with the TGF-ß1/Smad-2/3/Ets-1 signaling pathway in EAM mice.

13.
ACS Omega ; 7(10): 8819-8823, 2022 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-35309449

RESUMEN

As the physical scaling limit of silicon-based integrated circuits is approached, new materials and device structures become necessary. The exclusive-OR (XOR) gate is a basic logic gate performed as a building block for digital adder and encrypted circuits. Here, we suggest that using the ambipolar property of carbon nanotubes and the threshold modulation ability of dual-gate field-effect transistors, an XOR gate can be constructed in only one transistor. For a traditional XOR gate, 4 to 6 transistors are needed, and this low-footprint topology could be employed in the future for hyperscaling and three-dimensional logic and memory transistor integration.

15.
Adv Sci (Weinh) ; 9(14): e2200054, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35293698

RESUMEN

Structural control of single-wall carbon nanotubes (SWCNTs) with uniform properties is critical not only for their property modulation and functional design but also for applications in electronics, optics, and optoelectronics. To achieve this goal, various separation techniques have been developed in the past 20 years through which separation of high-purity semiconducting/metallic SWCNTs, single-chirality species, and even their enantiomers have been achieved. This progress has promoted the property modulation of SWCNTs and the development of SWCNT-based optoelectronic devices. Here, the recent advances in the structure separation of SWCNTs are reviewed, from metallic/semiconducting SWCNTs, to single-chirality species, and to enantiomers by several typical separation techniques and the application of the corresponding sorted SWCNTs. Based on the separation procedure, efficiency, and scalability, as well as, the separable SWCNT species, purity, and quantity, the advantages and disadvantages of various separation techniques are compared. Combined with the requirements of SWCNT application, the challenges, prospects, and development direction of structure separation are further discussed.

16.
Materials (Basel) ; 15(2)2022 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-35057265

RESUMEN

Hydrogen permeation barrier plays an important role in reducing hydrogen loss from zirconium hydride matrix when used as neutron moderator. Here, a composite nitride film was prepared on zirconium hydride by in situ reaction method in nitrogen atmosphere. The phase structure, morphology, element distribution, and valence states of the composite film were investigated by XRD, SEM, AES, and XPS analysis. It was found that the composite nitride film was continuous and dense with about 1.6 µm thickness; the major phase of the film was ZrN, with coexistence of ZrO2, ZrO, and ZrN0.36H0.8; and Zr-C, Zr-O, Zr-N, O-H, and N-H bonds were detected in the film. The existence of ZrN0.36H0.8 phase and the bonds of O-H and N-H revealed that the nitrogen and oxygen in the film could capture hydrogen from the zirconium hydride matrix. The hydrogen permeation performance of nitride film was compared with oxide film by permeation reduction factor (PRF), vacuum thermal dehydrogenation (VTD), and hydrogen permeation rate (HPR) methods, and the results showed that the hydrogen permeation barrier effects of nitride film were better than that of oxide film. The zirconium nitride film would be a potential candidate for hydrogen permeation barrier on the surface of zirconium hydride.

17.
Sci Total Environ ; 820: 153258, 2022 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-35065110

RESUMEN

Dissolved organic matter (DOM) is composed of numerous fluorescent components. It is an indispensable parameter to affect the environmental fate of antibiotics in various ways. To assess the migration of antibiotics in environment compartments, it is crucial to understand the binding mechanism between DOM and antibiotics. How a particular component in DOM interacts with coexistence antibiotics is not still fully understood. Therefore, in the present study, interactions of two antibiotics oxytetracycline (OTC) and sulfadiazine (SD) with humic acid (HA) and L-tryptophan (L-Trp) which were representative DOM components, were investigated by multispectral techniques and density functional theory (DFT) calculations. The fluorescence quenching mechanism was static quenching. In the binding process, the quenching ability of OTC was stronger than that of SD in HA, which was the same as in L-Trp. DFT calculations were applied to confirm a stronger interaction between OTC and HA or L-Trp than SD. Meanwhile, analyzing the binding sequence by two-dimensional correlation spectroscopy (2D-COS), a humic-like substance bound antibiotics was earlier than a protein-like substance. In HA system, the combination of two antibiotics had a synergistic effect on HA quenching. In L-Trp system, the quenching relationship between the two antibiotics and L-Trp was antagonistic. The FTIR spectra showed that hydroxyl and amide were involved in the binding process of individual DOM components with OTC and SD. The work will help to further understand the behavior of coexistence antibiotics in the environment.


Asunto(s)
Oxitetraciclina , Antibacterianos/química , Teoría Funcional de la Densidad , Materia Orgánica Disuelta , Espectrometría de Fluorescencia/métodos , Sulfadiazina
18.
Environ Sci Pollut Res Int ; 29(25): 38410-38424, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35076844

RESUMEN

The hyporheic zone (HZ) is an active biogeochemical region where groundwater and surface water mix and a potential reservoir for antibiotic resistance genes (ARGs). In this paper, the relative abundance and spatial distribution of ARGs in the HZ media were investigated, taking into consideration both the five speciation of six metals and the local characteristics. The samples of surface water, groundwater, and sediment were collected from Zaohe-Weihe Rivers of Xi'an City, which is a representative city with characteristics of the northwest region of China. Of 271 ARGs associated with 9 antibiotics, 228 ARGs were detected, with a total detection rate of 84%. Sulfonamide and aminoglycoside ARGs were the dominant types of ARGs. The top 6 ARGs and mobile genetic elements (MGEs) in terms of abundance were tnpA-04, cepA, sul1, aadA2-03, sul2 and intI1. The results of principal component analysis (PCA) showed that the distribution characteristics of ARGs were not associated with the sampling sites but with the environmental medias. Similarity in the water phases and significant differences in the water and sediment phases were found. The redundancy analysis (RDA) identified the key factors controlling ARG pollution, including dissolved oxygen (DO) in surface water, total nitrogen (TN) in groundwater, and total organic carbon (TOC) in sediment. In terms of the speciation of heavy metals, we further revealed the promotion effect between ARGs and heavy metals, especially the residual fraction of Ni. In terms of horizontal transfer mechanism, ARGs were significantly correlated with tnpA-03 in water phase and tnpA-04 in sediment. In the three media, intI1 and ARGs all show a significant correlation. These findings showed that hyporheic zone exerted a bottleneck effect on the distribution and transfer of ARGs.


Asunto(s)
Metales Pesados , Ríos , Antibacterianos/farmacología , China , Farmacorresistencia Microbiana/genética , Genes Bacterianos , Metales Pesados/análisis , Agua/análisis
19.
Sci Total Environ ; 807(Pt 2): 151011, 2022 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-34715223

RESUMEN

The emergence and pollution of antibiotics in surface water in various regions have drawn widespread concern because of the harm to aquatic ecosystems and human health. In this study, we aim to first investigate contamination and ecological risks of 39 antibiotics in Xiong'an New Area (XANA), China, and then illuminate relative abundances of antibiotic resistance genes (ARGs) and their correlations with antibiotics. The sum of antibiotic concentrations in the water circulation system, including surface water, groundwater, and sediment was 12.71-260.56 ng/L, ND-196.12 ng/L, and 38.03-406.31 ng/g, respectively. In surface water and sediment, cephalosporins and quinolones were the primary antibiotics, accounting for 45% and 16% of the total antibiotic concentrations in surface water and for 62% and 32% of the total antibiotic concentrations in sediment; this suggests a significant interaction between the two media. The antibiotic concentration was the highest in shallow groundwater at depths of <50 m (mean concentration of 79.22 ± 56.46 ng/L), indicating that surface water was a possible source of antibiotic contamination in groundwater. AMX presented the highest risk in both surface and groundwater and should be controlled as a priority. Moreover, the selection pressure of antibiotics on ARGs was discovered in the sediment in XANA, because the enrichment of sulA was significantly correlated with spiramycin and lincomycin and the enrichment of blaOXA-1 was significantly correlated with roxithromycin, ciprofloxacin, ofloxacin, and sulfapyridine. Thus, our investigation revealed potential antibiotic contamination in multiple environmental media in XANA, which should be addressed to prevent more serious pollution.


Asunto(s)
Antibacterianos , Agua Subterránea , China , Farmacorresistencia Microbiana/genética , Ecosistema , Humanos , Agua
20.
Materials (Basel) ; 16(1)2022 Dec 30.
Artículo en Inglés | MEDLINE | ID: mdl-36614696

RESUMEN

Nitride film as a hydrogen permeation barrier on zirconium hydride has seldom been studied. In this work, the zirconium nitride films were prepared on zirconium hydride in an atmosphere of N2 and N2 + H2 at 500~800 °C, with a holding time of 5 h and 20 h, and the mechanisms of film growth and hydrogen permeation were analyzed. The results showed that the film growth was mostly influenced by the temperature, followed by the reaction atmosphere and the holding time. The hydrogen could increase the nitrogen diffusivity during the formation of zirconium nitride films. The in situ nitriding conditions were optimized as 800 °C, N2 + H2 atmosphere, and 5~20 h. The chemical composition of ZrN-based films was mainly comprised of Zr and N, with a minor content of O. In addition, the film exhibited a major phase of ZrN, accompanied by the coexistence of ZrO2, ZrO, ZrN(NH2), and ZrN0.36H0.8, as well as O-H and N-H bonds based on the XPS analysis. The as-prepared ZrN base films in the present study exhibited superior hydrogen permeation resistance to other ZrO2 films previously reported. The hydrogen permeation resistance of the films could be attributed to the following mechanisms, including the chemical capture of hydrogen by the above-mentioned compounds and bonds; the physical barrier of continuous and dense film incurred from the volume effect of different compounds based on Pilling-Bedworth model and the different nitrogen diffusion coefficients at different temperatures.

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