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1.
Neural Regen Res ; 18(2): 404-409, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35900437

RESUMO

Our previous study demonstrated the potential therapeutic role of human neural stem cell-derived exosomes (hNSC-Exo) in ischemic stroke. Here, we loaded brain-derived neurotrophic factor (BDNF) into exosomes derived from NSCs to construct engineered exosomes (BDNF-hNSC-Exo) and compared their effects with those of hNSC-Exo on ischemic stroke both in vitro and in vivo. In a model of H2O2-induced oxidative stress in NSCs, BDNF-hNSC-Exo markedly enhanced cell survival. In a rat middle cerebral artery occlusion model, BDNF-hNSC-Exo not only inhibited the activation of microglia, but also promoted the differentiation of endogenous NSCs into neurons. These results suggest that BDNF can improve the function of NSC-derived exosomes in the treatment of ischemic stroke. Our research may support the clinical use of other neurotrophic factors for central nervous system diseases.

2.
Front Public Health ; 10: 874993, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35910877

RESUMO

Objectives: Health-related physical-fitness (HRPF) involves multi-components of physical functional tests and is reported to be associated with the risk of fall. The study sought to determine whether specific physical fitness components were stronger predictors of falls among elderly people. Methods: This prospective cohort study involved 299 community residents age ≥60 years from Shanghai, China. The baseline data included comprehensive assessment of sociodemographic, clinical, and HRPF test. Subjects were followed for 1 year and were contacted by telephone to report falls. LASSO regression and Multivariate regression analysis were used to identify risk predictors of fall. In addition, we used receiver operating characteristic (ROC) curve analyses to determine whether the predictors have diagnostic. Results: During the 1-year prospective fall assessment, 11.7% of these subjects experienced one or frequent falls. LASSO models revealed that age (=0.01) and 8-ft up-and-go test score (=0.06) were positively associated with falls, while activity-specific balance confidence (ABC; = -0.007) and 2-min step test score (= -0.005) were inversely related. The Area Under roc Curve (AUC) for a linear combination of age, ABC scale score, 2-min step test and 8-ft up-and-go test was 0.778 (95% confidence interval: 0. 700-0.857), which was superior to any of the variables taken alone. Conclusion: Age, activity-specific balance confidence and fitness abnormalities were determined to contribute to the incident of falls. The value of 2-min step test score, and 8-ft up-and-go test score were the key HRPF components in predicting falls among elderly people.


Assuntos
Avaliação Geriátrica , Aptidão Física , Idoso , China/epidemiologia , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco
3.
ACS Omega ; 7(29): 24942-24950, 2022 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-35910152

RESUMO

The abiotic reaction products of polycyclic aromatic hydrocarbons (PAHs) with hydroxyl radicals (•OH) and nitrate radicals (•NO3) are nitro-, oxygen-, and hydroxyl-containing PAHs (NPAHs, OPAHs, and OHPAHs). Four methods of the highest occupied molecular orbital (HOMO), Fukui function (FF), dual descriptor (DD), and population of π electrons (PP-π) are selected to predict the chemical reactivity of PAHs attacked by •OH and •NO3 in this study. The predicted •OH-initiated and •NO3-initiated transformation products are compared with the main PAH transformation products (PAH-TPs) observed in the laboratory. The results indicate that PP-π and DD approaches fail to predict the transformation products of fused PAHs containing five-membered rings. By predicting the PAH-TPs of 13-14 out of the 15 parent PAHs accurately, HOMO and FF methods were shown to be suitable for predicting the transformation products formed from the abiotic reactions of fused PAHs with •OH and •NO3.

4.
Int J Clin Health Psychol ; : 100327, 2022 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-35910285

RESUMO

Background/Objective: This study aimed to examine associations of the impact of COVID-19 pandemic on family life with emotional and behavioral health among preschool children. Methods: A longitudinal study including 1595 preschool children aged 3-6 years and their families was conducted in Anhui Province. The linear regression was applied to examine associations between the impact of COVID-19 pandemic on family life and emotional and behavioral health. Results: Results of the multivariable linear regression indicated that the severe impact of COVID-19 pandemic on family life was significantly associated with more sleep problems, poor dietary behavior habits, more anxiety symptoms, and more problematic behaviors; and these effects exhibited gender and age differences. Conclusions: The severe impact of COVID-19 pandemic on family life significantly increased the risk for exacerbated emotional and behavioral health among preschool children. It is considered vital to identify risk factors for vulnerable families and then to implement precise interventions when necessary for emotional and behavioral health of children in these families.

5.
Pathol Oncol Res ; 28: 1610360, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35911441

RESUMO

ERBB2 abnormalities frequently occur and serve as rationale therapeutic targets in cancer. In this study, clinical and next-generation sequencing data from 14,956 patients across more than 20 tumor types were collected. A total of 406 (2.7%) patients were identified with ERBB2 amplifications, and 303 (2.0%) patients with pathogenic somatic ERBB2 mutations. ERBB2 amplifications fell most frequently in breast (15.9%) and stomach (8.3%) cancers. Somatic ERBB2 SNVs/indels occurred most common in bladder/urinary tract (7.3%) and intestine (6.1%) cancers. The top mutated ERBB2 SNVs/indels were p.Y772_A775dup (25.5%) and p.S310F/Y (19.9%). Significantly higher rates of ERBB2 SNV/indels were found in women compared to men (2.8% vs. 1.5%, p < 0.0001). CDK12 was the most common co-amplification gene with ERBB2 in cancers with a high frequency of ERBB2 amplifications. Patients with ERBB2 amplifications or mutations had higher TMB compared with patients with non-ERBB2 alterations. The study provided the landscape of ERBB2 alterations across a variety of solid tumors that may benefit from anti-HER2 agents.


Assuntos
Neoplasias , Receptor ErbB-2 , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Mutação , Neoplasias/genética , Receptor ErbB-2/genética
6.
Mitochondrial DNA B Resour ; 7(7): 1350-1351, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35911471

RESUMO

We report the complete mitochondrial genome of Cuora mccordi. The complete genome is a closed circular molecule of 16,551 bp, with an overall base composition of 34.06% for A, 26.73% for T, 12.84% for G, and 26.37% for C. The A + T content is 60.79%. The full length consists of 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and one control region (D-loop). Phylogenetic analysis results showed that the mitogenome of Cuora mccordi was the closest to Cuora pani. The complete mitochondrial genome of Cuora mccordi (GenBank accession number: OM327796) can aid in understanding evolutionary relationships within Cuora.

7.
Comput Math Methods Med ; 2022: 3436631, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35912147

RESUMO

Objective: To develop and authenticate a risk stratification framework and nomogram for ascertaining cancer-specific survival (CSS) among the pediatric brainstem gliomas. Methods: For patients less than 12 years, according to Surveillance, Epidemiology, and End Results (SEER), information from 1998 to 2016 is found in their databases. The survival outcomes, treatments, and demographic clinicopathologic conditions are scrutinized per the database validation, and training cohorts are divided and validated using multivariate Cox regression analysis. A nomogram was designed, and predominantly, the risk stratification conceptualization engaged selected tenets according to the multivariate analysis. The model's authenticity was substantiated through C-index measure and calibration curves. Results: There are 806 pediatric concerns of histologically concluded brainstem glioma in the research. According to multivariate analysis, age, grade, radiotherapy, and race (with P value < 0.05) depicted independent prognostic variations of the pediatric gliomas. The nomogram's C-index was approximately 0.75 and an accompanied predictive capability for CSS. Conclusion: The nomogram constructed in this glioma's context is the primary predictor of using risk stratification. A combination of nomograms with the risk stratification mechanism assists clinicians in monitoring high-risk individuals and engage targeted accessory treatment.


Assuntos
Glioma , Nomogramas , Tronco Encefálico , Criança , Glioma/terapia , Humanos , Prognóstico , Medição de Risco/métodos , Programa de SEER
8.
Artigo em Inglês | MEDLINE | ID: mdl-35917074

RESUMO

Amounting epidemiological evidence has shown detrimental effects of heavy metals on a wide range of diseases. However, the effect of heavy metal exposure on mortality in the general population remains unclear. The primary objective of this study was to clarify the associations between heavy metals and mortality from all causes, cardiovascular disease (CVD), and cancer based on prospective studies. We comprehensively searched Pubmed, Embase, and Web of Science electronic databases to identify studies published from their inception until 1 March 2022. Investigators identified inclusion criteria, extracted study characteristics, and assessed the methodological quality of included studies according to standardized guidelines. Meta-analysis was conducted if the effect estimates of the same outcome were reported in at least three studies. Finally, 42 original studies were identified. The results of meta-analysis showed that cadmium and lead exposure was significantly associated with mortality from all causes, CVD, and cancer in the general population. Moderate evidence suggested there was a link between arsenic exposure and mortality. The adverse effects of mercury and other heavy metals on mortality were inconclusive. Epidemiological evidence for the joint effect of heavy metal exposure on mortality was still indeterminate. In summary, our study provided compelling evidence that exposure to cadmium, lead, and arsenic were associated with mortality from all causes, CVD, and cancer, while the evidence on other heavy metals, for example mercury, was insignificant or indeterminate. Nevertheless, further prospective studies are warranted to explore the joint effects of multiple metal exposure on mortality.

9.
Biol Trace Elem Res ; 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35915279

RESUMO

The objective of this study was to determine the relationship of urinary nickel (U-Ni) exposure to serum lipid profiles and the mediation effect of body mass index (BMI) in a US general population. We analyzed the cross-sectional data from 3517 participants in the National Health and Nutrition Examination Survey (NHANES) (2017-March 2020). Multivariable linear regression and restricted cubic spline (RCS) regression were conducted to explore the association of U-Ni with four serum lipids and four lipids-derived indicators. Mediation analysis was performed to examine the effect of BMI on the relationship between U-Ni levels and serum lipid profiles. Compared with the lowest quartile, the ß with 95% confidence intervals (CIs) in the highest quartile were - 12.83 (- 19.42, - 6.25) for total cholesterol (TC) (P for trend < 0.001), - 12.76 (- 19.78, - 5.74) for non-high-density lipoprotein cholesterol (non-HDL-C) (P for trend = 0.001) and - 0.29 (- 0.51, - 0.07) for TC/HDL-C (P for trend = 0.007) in the fully adjusted model. RCS plots showed the linear association of log2-transformed U-Ni levels with TC, non-HDL-C and TC/HDL-C (P for nonlinearity = 0.294, 0.152, and 0.087, respectively). Besides, BMI decreased monotonically in correlation with increasing U-Ni levels (P for trend < 0.001). Mediation analysis revealed that BMI significantly mediated the relationship of U-Ni to TC, non-HDL-C and TC/HDL-C with mediated proportions of 11.17%, 22.20% and 36.44%, respectively. In summary, our findings suggest that BMI mediates the negative association of U-Ni with TC, non-HDL-C, and TC/HDL-C in the US general population.

10.
J Med Virol ; 2022 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-35916043

RESUMO

Mammalian chromosomes undergo varying degrees of compression to form three-dimensional genome structures. These three-dimensional structures undergo dynamic and precise chromatin interactions to achieve precise spatial and temporal regulation of gene expression. Most eukaryotic DNA viruses can invade their genomes into the nucleus. However, it is still poorly understood how the viral genome is precisely positioned after entering the host cell nucleus to find the most suitable location and whether it can specifically interact with the host genome to hijack the host transcriptional factories or even integrate into the host genome to complete its transcription and replication rapidly. Chromosome conformation capture technology can reveal long-range chromatin interactions between different chromosomal sites in the nucleus, potentially providing a reference for viral DNA-host chromatin interactions. This review summarized the research progress on the three-dimensional interaction between virus and host genome and the impact of virus integration into the host genome on gene transcription regulation, aiming to provide new insights into chromatin interaction and viral gene transcription regulation, laying the foundation for the treatment of infectious diseases. This article is protected by copyright. All rights reserved.

11.
Artigo em Inglês | MEDLINE | ID: mdl-35926719

RESUMO

PURPOSE: We have determined the in vivo relative biological effectiveness (RBE) of an alpha-particle emitting radiopharmaceutical therapeutic (αRPT) agent (212Pb-labeled anti-HER-2/neu antibody) for the bone marrow, a potentially dose-limiting normal tissue. METHODS AND MATERIALS: The RBE was measured in mice using femur marrow cellularity as the biological endpoint. External beam radiotherapy (EBRT), delivered by a small animal radiation research platform was used as the reference radiation. Alpha-particle emissions were delivered by 212Bi, following the decay of its parent nuclide 212Pb, conjugated onto an anti-HER2/neu antibody. The alpha-particle absorbed dose to the marrow following intravenously administered (tail vein) 122.1-921.3 kBq 212Pb-TCMC-7.16.4 was calculated. Mice were sacrificed at 0-7 days post-treatment (dpt) and femur bone marrow was counted for radioactivity. Changes in marrow cellularity were assessed by histopathology. RESULTS: The dose-response for EBRT and 212Pb-anti-HER2/neu antibody were linear-quadratic and linear, respectively. By transforming the EBRT dose-response relationship into a linear relationship using the EQD2 formalism we obtained an RBE (denoted RBE2) of 6.4; this value is independent of cellularity and absorbed dose. CONCLUSIONS: Since hematologic toxicity is dose-limiting in almost all antibody-based RPT, in vivo measurements of RBE are important in helping identify an initial administered activity (AA) in phase 1 escalation trials. Applying the RBE2 and assuming typical antibody clearance kinetics (Biological half-life of 48 h) with a modified blood-based dosimetry method, an average AA of approximately 185.5 MBq (5.0 mCi) per patient could be administered before hematologic toxicity is anticipated.

13.
Oral Dis ; 2022 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-35925052

RESUMO

OBJECTIVE: The purpose of this study is to explore the effects of MVBML approach on postoperative facial scar, nerves injury and prognosis of patients with BSCC. PATIENTS AND METHODS: This is a single-center, prospective cohort study that enrolled 80 patients with BSCC from June 2015 to December 2020. According to the different surgical approaches, the patients were divided into two groups: the lower lip median (LLM) approach group and the modified vermilion border-marionette line (MVBML) approach group. RESULTS: The results showed that the appearance (p=0.003), scar consciousness (p<0.001) and satisfaction with appearance (p=0.001) of patients in the MVBML group were significantly better than those in the LLM group, and the difference was more obvious in elderly group. Statistical analysis of postoperative nerves injury showed that the MVBML group had a lower risk of facial and mental nerves injury than the LLM group, and there was a significant statistical difference in mental nerve injury between the two groups (p<0.001). Through Kaplan-Meier survival analysis, we found no significant difference in disease-specific survival (p=0.47) or disease-free survival (p=0.70) between the LLM approach group and the MVBML approach group. CONCLUSIONS: The MVBML surgical approach is worthy of advancement for the surgical treatment of BSCC.

14.
Surg Oncol ; 44: 101818, 2022 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-35930900

RESUMO

BACKGROUND: Breast cancer (BC) is a common malignant tumor. Apatinib in combination with other treatments has been used for BC; however, its safety and efficacy are not well-known. Therefore, this meta-analysis was performed to assess the efficacy and safety of apatinib in the treatment of BC. METHODS: Studies comparing the effects of apatinib-based therapy versus control among BC patients were included. On January 21, 2022, a systematic search was performed in 9 databases. The risk ratio (RR) with 95% confidence interval (CI) was used to estimate efficacy and safety. The I square value (I2) was used to assess heterogeneity. A leave-one-out sensitivity analysis was also conducted. Publication bias was assessed by funnel plots and Egger's and Begg's tests. RESULTS: A total of 31 studies including 2,258 BC patients were included. The results showed that apatinib group had a significant improvement in disease control rate (DCR, RR = 1.43, 95% CI = 1.35-1.52, I2 = 43.8%) and objective response rate (ORR, RR = 1.79, 95% CI = 1.51-2.13, I2 = 61.8%) compared to the control group. Except for hemorrhage, hypertension, and hand-foot syndrome, the adverse events were similar between apatinib group and control group. Subgroup analyses found statistically significant differences in DCR in all subgroups except for apatinib combined with radiation therapy and with paclitaxel liposome plus S1. For ORR, there were statistically significant differences in all subgroups except for the radiation therapy, and apatinib monotherapy subgroups. CONCLUSIONS: Our study shown apatinib showed good efficacy and acceptable safety in the treatment of BC patients. More high-quality randomized controlled trials from different regions and countries are needed to confirm our findings.

15.
Mediators Inflamm ; 2022: 6077570, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35915740

RESUMO

Introduction: When sepsis attacks the body, the excessive reactive oxygen species (ROS) production can result to endoplasmic reticulum stress (ERS) and eventually cause lymphocyte apoptosis. The mammalian target of rapamycin (mTOR) is essential for regulating lymphocyte apoptosis; we hypothesized that it mediates CD4+ T cell apoptosis during ROS-related ERS. Method: We, respectively, used ROS and ERS blockers to intervene septic mice and then detected ERS protein expression levels to verify the relationship between them. Additionally, we constructed T cell-specific mTOR and TSC1 gene knockout mice to determine the role of mTOR in ROS-mediated, ERS-induced CD4+ T cell apoptosis. Results: Blocking ROS significantly suppressed the CD4+ T cell apoptosis associated with the reduction in ERS, as revealed by lower levels of GRP78 and CHOP. ERS rapidly induced mTOR activation, leading to the induction of CD4+ T cell apoptosis. However, mTOR knockout mice displayed reduced expression of apoptotic proteins and less ER vesiculation and expansion than what was observed in the wild-type sepsis controls. Conclusion: By working to alleviate ROS-mediated, ERS-induced CD4+ T cell apoptosis, the mTOR pathway is vital for CD4+ T cell survival in sepsis mouse model.


Assuntos
Estresse do Retículo Endoplasmático , Sepse , Animais , Apoptose , Linfócitos T CD4-Positivos/metabolismo , Terapia de Imunossupressão , Mamíferos/metabolismo , Camundongos , Espécies Reativas de Oxigênio/metabolismo , Serina-Treonina Quinases TOR
16.
Cancer Med ; 2022 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-35833662

RESUMO

BACKGROUND: The wide applicability of the Naples prognostic score (NPS) is still worthy of further study in gastric cancer (GC). This study aimed to construct a New-NPS based on the differences in immunity and nutrition in patients with upper and lower gastrointestinal tumors to help obtain an individualized prediction of prognosis. METHODS: This study retrospectively analyzed patients who underwent radical gastrectomy from April 2014 to September 2016. The cutoff values of the preoperative neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), serum albumin (Alb), and total cholesterol (TC) were calculated by ROC curve analysis. ROC and t-ROC were used to evaluate the accuracy of the prognostic markers. The Kaplan-Meier method and log-rank test were used to analyze the overall survival probability. Univariate and multivariate analyses based on Cox risk regression were used to show the independent predictors. The nomogram was made by R studio. The predictive accuracy of nomogram was assessed using a calibration plot, concordance index (C-index), and decision curve. RESULTS: A total of 737 patients were included in training cohort, 411 patients were included in validation cohort. ROC showed that the New-NPS was more suitable for predicting the prognosis of GC patients. NPS = 2 indicated a poor prognosis. Multivariate analysis showed that CEA (P = 0.026), Borrmann type (P = 0.001), pTNM (P < 0.001), New-NPS (P < 0.001), and nerve infiltration (P = 0.035) were independent risk factors for prognosis. CONCLUSION: The New-NPS based on the cutoff values of NLR, LMR, Alb, and TC is not only suitable for predicting prognosis but can also be combined with clinicopathological characteristics to construct a nomogram model for GC patients.

17.
Water Res ; 221: 118793, 2022 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-35779454

RESUMO

This study proposed that decreasing liquid polarity could weaken the intermolecular polar force at solid-liquid interface of waste-activated sludge (WAS). Accordingly, a process for enhanced sludge dewatering through liquid polarity regulation was established. The liquid polarity was quantified by dielectric constant and the decrease of liquid dielectric constant below 50 was found to significantly improve the solid-liquid separation performance of WAS in terms of filterability by >70%. The differential scanning calorimeter (DSC) coupled with mass spectrum (MS) identified that 60 °C was the appropriate temperature for liquid amendment (i.e., acetonitrile) recovery from filtered sludge cake, and the corresponding energy consumption was calculated to be at most 799.0 J/g, which was substantially lower than that of water evaporation by sludge drying. The NaCl addition with 75% of saturated concentration could non-thermally recover 91.7 ± 4.9% of acetonitrile amendment from filtrate by salting-out. The great potentials in energy saving and recycle of chemicals make the newly proposed approach act as alternatives for the conventional process (i.e., mechanically dewatering + drying). Regarding the mechanism of liquid polarity regulation for enhanced WAS dewatering, the solid-liquid interfacial free energy was found to be reduced by 39.4% with the liquid dielectric constant decreasing from 78.50 to 41.00. Also, Tandem Mass Tags (TMT) proteomics tracked the phase-transfer of amphiphilic proteins with decreasing liquid polarity, which found that the solubilization of proteins involved in the Gene Ontology (GO) classifications of "membrane protein complex" and "membrane protein complex/outer membrane" could facilitate the enhanced solid-liquid separation of WAS. The conformational analysis on those differential proteins was further conducted to reveal the structure attributes of amphiphilic proteins for the phase-transfer feature. The proteins with more exposed amino acid residues (i.e., average solvent accessibility index over 1.8) tended to dissolve in the liquid phase with lower polarity, which was accompanied with the reduced interfacial free energy of WAS. On the contrary, the proteins with buried amino acid residues (e.g., the central hydrophobic ß-sheet is surrounded by the hydrophilic α-helix) precipitated in the solid phase with the decreasing liquid polarity. All these findings are expected to create a novel option for dewatering WAS with recyclable liquid conditioning agents, and provide the improved mechanistic insights into the migration of interfacial compositions controlling the dewaterability of WAS.

18.
Plants (Basel) ; 11(13)2022 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-35807681

RESUMO

Based on the complete chloroplast genome, morphology, and karyotype evidence, we identified a new nothospecies, Lycoris × jinzheniae S.Y. Zhang, P.C. Zhang & J.W. Shao, in eastern China. This new nothospecies has been inappropriately named Lycoris × albiflora in the previous literature for more than 30 years. However, the new nothospecies resulted from the hybridization of L. sprengeri and L. chinensis and had the following characteristics: the karyotype was 2n = 19 = 3V + 16I, the leaves emerged in the spring, the ratio of filament to corolla length was approximately 1.2, tepals were slightly undulated and curved, and it was distributed throughout eastern China. These characteristics are quite different from those of L. × albiflora; thus, in this study, we named it and provided a detailed morphological description and diagnosis.

19.
Nanomaterials (Basel) ; 12(13)2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35807962

RESUMO

This paper studies the synergistic effect of total ionizing dose (TID) and displacement damage dose (DDD) in enhancement-mode GaN high electron mobility transistor (HEMT) based on the p-GaN gate and cascode structure using neutron and 60Co gamma-ray irradiation. The results show that when the accumulated gamma-ray doses are up to 800k rad(Si), the leakage-current degradations of the two types of GaN HEMTs with 14 MeV neutron irradiation of 1.3 × 1012 n/cm2 and 3 × 1012 n/cm2 exhibit a lower degradation than the sum of the two separated effects. However, the threshold voltage shifts of the cascode structure GaN HEMT show a higher degradation when exposed to both TID and DDD effects. Moreover, the failure mechanisms of the synergistic effect in GaN HEMT are investigated using the scanning electron microscopy technique. It is shown that for the p-GaNHEMT, the increase in channel resistance and the degradation of two-dimensional electron gas mobility caused by neutron irradiation suppresses the increase in the TID leakage current. For the cascode structure HEMT, the neutron radiation-generated defects in the oxide layer of the metal-oxide-semiconductor field-effect transistor might capture holes induced by gamma-ray irradiation, resulting in a further increase in the number of trapped charges in the oxide layer.

20.
Nanomaterials (Basel) ; 12(13)2022 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-35807992

RESUMO

Supported metal catalysts are widely used in industrial processes, and the particle size of the active metal plays a key role in determining the catalytic activity. Herein, CeO2-supported Ni catalysts with different Ni loading and particle size were prepared by the impregnation method, and the hydrogenation performance of maleic anhydride (MA) over the Ni/CeO2 catalysts was investigated deeply. It was found that changes in Ni loading causes changes in metal particle size and active sites, which significantly affected the conversion and selectivity of MAH reaction. The conversion of MA reached the maximum at about 17.5 Ni loading compared with other contents of Ni loading because of its proper particle size and active sites. In addition, the effects of Ni grain size, surface oxygen vacancy, and Ni-CeO2 interaction on MAH were investigated in detail, and the possible mechanism for MAH over Ni/CeO2 catalysts was deduced. This work greatly deepens the fundamental understanding of Ni loading and size regimes over Ni/CeO2 catalysts for the hydrogenation of MA and provides a theoretical and experimental basis for the preparation of high-activity catalysts for MAH.

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