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1.
Aging (Albany NY) ; 16(3): 3007-3020, 2024 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-38345576

RESUMO

Related studies have shown that ITGB2 mediates mitochondrial glycolytic transformation in cancer-associated fibroblasts and participates in tumor occurrence, metastasis and invasion of cancer cells. Based on these studies, we tried to construct a mitochondrial glycolysis regulatory network and explored its effect on mitochondrial homeostasis and ovarian cancer cells' cancerous characteristics. Our research revealed a distinct increase in the expression of ITGB2 and associated signaling pathway elements (PI3K-AKT-mTOR) in cases of ovarian cancer. ITGB2 might control mTOR expression via the PI3K-AKT pathway, thus promote mitochondrial glycolysis transformation and cell energy supply in ovarian cancer. This pathway could also inhibit mitophagy, maintain mitochondrial stability, and enhance the cancerous characteristics in case of ovarian cancer cells by mediating mitochondrial glycolytic transformation. Thus, we concluded that ITGB2-associated signaling route (PI3K-AKT-mTOR) may contribute to the progression of cancerous traits in ovarian cancer via mediating mitochondrial glycolytic transformation.


Assuntos
Neoplasias Ovarianas , Proteínas Proto-Oncogênicas c-akt , Humanos , Feminino , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Linhagem Celular Tumoral , Neoplasias Ovarianas/patologia , Serina-Treonina Quinases TOR/metabolismo , Glicólise , Proliferação de Células
2.
Oncol Res ; 31(2): 169-179, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37304234

RESUMO

Previous study revealed that ferritin heavy chain-1 (FTH1) could regulate ferritinophagy and affect intracellular Fe2+ content in various tumors, while its N6-methyladenosine (m6A) RNA methylation was closely related the prognosis of ovarian cancer patients. However, little is known about the role of FTH1 m6A methylation in ovarian cancer (OC) and its possible action mechanisms. In this study we constructed FTH1 m6A methylation regulatory pathway (LncRNA CACNA1G-AS1/IGF2BP1) according to related bioinformatics analysis and research, through clinical sample detections we found that these pathway regulatory factors were significantly up-regulated in ovarian cancer tissues, and their expression levels were closely related to the malignant phenotype of ovarian cancer. In vitro cell experiments showed that LncRNA CACNA1G-AS1 could up-regulate FTH1 expression through IGF2BP1 axis, thus inhibited ferroptosis by regulating ferritinophagy, and finally promoted proliferation and migration in ovarian cancer cells. Tumor-bearing mice studies showed that the knock-down of LncRNA CACNA1G-AS1 could inhibited the tumorigenesis of ovarian cancer cells in vivo condition. Our results demonstrated that LncRNA CACNA1G-AS1 could promote the malignant phenotypes of ovarian cancer cells through FTH1-IGF2BP1 regulated ferroptosis.


Assuntos
Canais de Cálcio Tipo T , Ferroptose , Neoplasias Ovarianas , RNA Longo não Codificante , Feminino , Animais , Humanos , Camundongos , Neoplasias Ovarianas/genética , RNA Longo não Codificante/genética , Ferroptose/genética , Adenosina , Fenótipo , Ferritinas , Oxirredutases
3.
BMC Genomics ; 24(1): 323, 2023 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-37312060

RESUMO

BACKGROUND: Gastric cancer (GC) carries significant morbidity and mortality globally. An increasing number of studies have confirmed that circular RNA (circRNA) is tightly associated with the carcinogenesis and development of GC, especially acting as a competing endogenous RNA for miRNAs. OBJECTIVE: Our study aimed to construct the circRNA-miRNA-mRNA regulatory network and analyze the function and prognostic significance of the network using bioinformatics tools. METHODS: We first downloaded the GC expression profile from the Gene Expression Omnibus database and identified differentially expressed genes and differentially expressed circRNAs. Then, we predicted the miRNA-mRNA interaction pairs and constructed the circRNA-miRNA-mRNA regulatory network. Next, we established a protein-protein interaction network and analyzed the function of these networks. Finally, we primarily validated our results by comparison with The Cancer Genome Atlas cohort and by performing qRT-PCR. RESULTS: We screened the top 15 hub genes and 3 core modules. Functional analysis showed that in the upregulated circRNA network, 15 hub genes were correlated with extracellular matrix organization and interaction. The function of downregulated circRNAs converged on physiological functions, such as protein processing, energy metabolism and gastric acid secretion. We ascertained 3 prognostic and immune infiltration-related genes, COL12A1, COL5A2, and THBS1, and built a nomogram for clinical application. We validated the expression level and diagnostic performance of key prognostic differentially expressed genes. CONCLUSIONS: In conclusion, we constructed two circRNA-miRNA-mRNA regulatory networks and identified 3 prognostic and screening biomarkers, COL12A1, COL5A2, and THBS1. The ceRNA network and these genes could play important roles in GC development, diagnosis and prognosis.


Assuntos
MicroRNAs , Neoplasias Gástricas , Humanos , MicroRNAs/genética , RNA Circular/genética , Neoplasias Gástricas/genética , RNA Mensageiro/genética , Prognóstico
4.
Cells ; 11(24)2022 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-36552889

RESUMO

OBJECTIVE: We aimed to construct the ferritin autophagy regulatory network and illustrate its mechanism in ferroptosis, TME immunity and malignant phenotypes of ovarian cancer. METHODS: First, we used Western blot assays and immunohistochemistry to detect the pathway expression in ovarian cancer samples (C-MYC, NCOA4). Then, we performed RIP and FISH analysis to verify the targeted binding of these factors after which we constructed ovarian cancer cell models and detected pathway regulator expression (NCOA4). Co-localization and Western blot assays were used to detect ferritin autophagy in different experimental groups. We selected corresponding kits to assess ROS contents in ovarian cancer cells. MMP was measured using flow cytometry and mitochondrial morphology was observed through TEM. Then, we chose Clone, EdU and Transwell to evaluate the proliferation and invasion abilities of ovarian cancer cells. We used Western blot assays to measure the DAMP content in ovarian cancer cell supernatants. Finally, we constructed tumor bearing models to study the effect of the C-MYC pathway on ovarian cancer tumorigenesis and TME immune infiltration in in vivo conditions. RESULTS: Through pathway expression detection, we confirmed that C-MYC was obviously up-regulated and NCOA4 was obviously down-regulated in ovarian cancer samples, while their expression levels were closely related to the malignancy degree of ovarian cancer. RIP, FISH and cell model detection revealed that C-MYC could down-regulate NCOA4 expression through directly targeted binding with its mRNA. Ferritin autophagy and ferroptosis detection showed that C-MYC could inhibit ferroptosis through NCOA4-mediated ferritin autophagy, thus reducing ROS and inhibiting mitophagy in ovarian cancer cells. Cell function tests showed that C-MYC could promote the proliferation and invasion of ovarian cancer cells through the NCOA4 axis. The Western blot assay revealed that C-MYC could reduce HMGB1 release in ovarian cancer cells through the NCOA4 axis. In vivo experiments showed that C-MYC could promote tumorigenesis and immune evasion in ovarian cancer cells through inhibiting HMGB1 release induced by NCOA4-mediated ferroptosis. CONCLUSION: According to these results, we concluded that C-MYC could down-regulate NCOA4 expression through directly targeted binding, thus inhibiting ferroptosis and promoting malignant phenotype/immune evasion in ovarian cancer cells through inhibiting ferritin autophagy.


Assuntos
Ferroptose , Coativadores de Receptor Nuclear , Neoplasias Ovarianas , Proteínas Proto-Oncogênicas c-myc , Feminino , Humanos , Autofagia , Carcinogênese , Ferritinas/metabolismo , Proteína HMGB1/metabolismo , Evasão da Resposta Imune , Coativadores de Receptor Nuclear/genética , Coativadores de Receptor Nuclear/metabolismo , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo
5.
Front Psychiatry ; 13: 928781, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35898631

RESUMO

Electroencephalogram (EEG)-based tools for brain functional connectivity (FC) analysis and visualization play an important role in evaluating brain cognitive function. However, existing similar FC analysis tools are not only visualized in 2 dimensions (2D) but also are highly prone to cause visual clutter and unable to dynamically reflect brain connectivity changes over time. Therefore, we design and implement an EEG-based FC visualization framework in this study, named EEG-FCV, for brain cognitive state evaluation. EEG-FCV is composed of three parts: the Data Processing module, Connectivity Analysis module, and Visualization module. Specially, FC is visualized in 3 dimensions (3D) by introducing three existing metrics: Pearson Correlation Coefficient (PCC), Coherence, and PLV. Furthermore, a novel metric named Comprehensive is proposed to solve the problem of visual clutter. EEG-FCV can also visualize dynamically brain FC changes over time. Experimental results on two available datasets show that EEG-FCV has not only results consistent with existing related studies on brain FC but also can reflect dynamically brain FC changes over time. We believe EEG-FCV could prompt further progress in brain cognitive function evaluation.

6.
Front Oncol ; 12: 854615, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35392242

RESUMO

Background: Increasing evidence suggests that tumour necrosis factor (TNF) family genes play important roles in cervical cancer (CC). However, whether TNF family genes can be used as prognostic biomarkers of CC and the molecular mechanisms of TNF family genes remain unclear. Methods: A total of 306 CC and 13 normal samples were obtained from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases. We identified differentially expressed TNF family genes between CC and normal samples and subjected them to univariate Cox regression analysis for selecting prognostic TNF family genes. Least absolute shrinkage and selection operator (LASSO) regression and multivariate Cox regression analyses were performed to screen genes to establish a TNF family gene signature. Gene set enrichment analysis (GSEA) was performed to investigate the biological functions of the TNF family gene signature. Finally, methylation and copy number variation data of CC were used to analyse the potential molecular mechanisms of TNF family genes. Results: A total of 26 differentially expressed TNF family genes were identified between the CC and normal samples. Next, a TNF family gene signature, including CD27, EDA, TNF, TNFRSF12A, TNFRSF13C, and TNFRSF9 was constructed based on univariate Cox, LASSO, and multivariate Cox regression analyses. The TNF family gene signature was related to age, pathological stages M and N, and could predict patient survival independently of clinical factors. Moreover, KEGG enrichment analysis suggested that the TNF family gene signature was mainly involved in the TGF-ß signaling pathway, and the TNF family gene signature could affect the immunotherapy response. Finally, we confirmed that the mRNA expressions of CD27, TNF, TNFRSF12A, TNFRSF13C, and TNFRSF9 were upregulated in CC, while that of EDA was downregulated. The mRNA expressions of CD27, EDA, TNF, TNFRSF12A, TNFRSF13C, and TNFRSF9 might be influenced by gene methylation and copy number variation. Conclusion: Our study is the first to demonstrate that CD27, EDA, TNF, TNFRSF12A, TNFRSF13C, and TNFRSF9 might be used as prognostic biomarkers of CC and are associated with the immunotherapy response of CC.

7.
Eur J Emerg Med ; 29(2): 105-117, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-34619690

RESUMO

This meta-analysis aimed to assess the diagnostic accuracy of lung ultrasonography in pneumonia-affected pediatric patients. Literature search of published articles in Medline, Web of Science, Scopus, Embase and Journal of Web till September 2020 were reviewed for the predescribed accuracy assessors. In compliance with the inclusion and exclusion criteria, two researchers independently screened the literature, collected the results and assessed the risks of bias using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. The pooled sensitivity and specificity, pooled positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio were estimated for the meta-analysis. The overall efficiency of lung ultrasonography (LUS) was evaluated using a summary receiver operating characteristic curve. Q and I2 statistics were used to determine heterogeneity. Meta disc software was used for the analysis of the study. Out of 1182 studies, only 29 articles were chosen; 25 of them were prospective studies and 4 studies were retrospective. The overall pooled sensitivity was 0.83 [95% confidence intervals (CI), 0.81-0.84] and specificity was 0.84 (95% CI, 0.81-0.86), depicting good diagnostic performance. LUS is an efficient imaging technique for detecting childhood pneumonia with a high accuracy rate. It is an appealing alternative to chest X rays to detect and follow-up pneumonia in children because it is simple to do, widely available, comparatively cheap and free of radiation hazards.


Assuntos
Pneumonia , Criança , Humanos , Pulmão/diagnóstico por imagem , Pneumonia/diagnóstico por imagem , Estudos Prospectivos , Estudos Retrospectivos , Sensibilidade e Especificidade , Ultrassonografia
8.
Front Cell Dev Biol ; 9: 629893, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33732698

RESUMO

The relevance of microRNA-15a (miR-15a) to autoimmunity has been reported. Herein, we intended to probe the potential roles of miR-15a shuttled by adipose-derived mesenchymal stem cells (adMSCs)-derived extracellular vesicles (Evs) in colorectal cancer (CRC). Initially, CRC cells were treated with interferon gamma (IFN-γ) to screen out differentially expressed genes by transcriptome sequencing. Following a 24-h co-culture with 20 µM adMSCs-derived Evs, CRC cell viability, migration, invasion, and apoptosis were assessed. After the determination of histone lysine demethylase 4B (KDM4B) as our target, its regulatory miRNA was predicted by the bioinformatics websites and verified by dual-luciferase and RNA pull-down assays. Intriguingly, KDM4B downregulated homeobox C4 (HOXC4) expression, while HOXC4 bound to the promoter sequence of programmed death-ligand 1 (PD-L1). Thus, we conducted rescue experiments to study the role of KDM4B and HOXC4. Finally, we evaluated the effects of adMSCs on CRC cell growth and immune evasion through in vivo tumorigenesis experiments. AdMSCs-derived Evs overexpressing miR-15a repressed proliferation, migration, and invasion, while it promoted the apoptosis of CRC cells via downregulation of KDM4B. These in vivo findings were reproduced in vitro on CRC immune evasion. Collectively, adMSCs-derived Evs overexpressing miR-15a restricted the immune evasion of CRC via the KDM4B/HOXC4/PD-L1 axis.

9.
Cancer Cell Int ; 20: 439, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32943987

RESUMO

BACKGROUND: KLF5 is a member of the Kruppel-like factor, subfamily of zinc finger proteins that are involved in cancers. KLF5 functions as a transcription factor and regulates the diverse protein-coding genes (PCGs) in colorectal cancer (CRC). However, the long non-coding RNAs (lncRNAs) regulated by KLF5 in CRC are currently unknown. METHODS: In this study, we first designed a computational pipeline to determine the PCG and lncRNA targets of KLF5 in CRC. Then we analyzed the motif pattern of the binding regions for the lncRNA targets. The regulatory co-factors of KLF5 were then searched for through bioinformatics analysis. We also constructed a regulatory network for KLF5 and annotated its functions. Finally, one of the KLF5 lncRNA targets, SNHG12, was selected to further explore its expression pattern and functions in CRC. RESULTS: We were able to identify 19 lncRNA targets of KLF5 and found that the motifs of the lncRNA binding sites were GC-enriched. Next, we pinpointed the transcription factors AR and HSF1 as the regulatory co-factors of KLF5 through bioinformatics analysis. Then, through the analysis of the regulatory network, we found that KLF5 may be involved in DNA replication, DNA repair, and the cell cycle. Furthermore, in the cell cycle module, the SNHG12 up-regulating expression pattern was verified in the CRC cell lines and tissues, associating it to CRC invasion and distal metastasis. This indicates that SNHG12 may play a critical part in CRC tumorigenesis and progression. Additionally, expression of SNHG12 was found to be down-regulated in CRC cell lines when KLF5 expression was knocked-down by siRNA; and a strong correlation was observed between the expression levels of SNHG12 and KLF5, further alluding to their regulatory relationship. CONCLUSIONS: In conclusion, the network analysis of KLF5 targets indicates that SNHG12 may be a significant lncRNA in CRC.

10.
Appl Opt ; 59(12): 3686-3691, 2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-32400491

RESUMO

Chirality has received wide attention due to its promising applications in biopharmaceuticals, chemical detection, and polarized optoelectronic devices. Herein, metamaterials with layered Tai Chi patterns are proposed to get strong and tunable chirality. Based on the surface current distribution analysis, a coupling model considering both the magnetic and electric dipoles in the upper and bottom metallic structures is proposed to understand the circular dichroism. Accordingly, both an external chiral modulation by changing the incident angle and an internal chiral modulation by changing the twist angle are achieved. Incident-angle-dependent circular dichroism modulation exhibits a range of 0.44-0.62 and the twist-angle-dependent modulation range is ${-}{0.6 - 0.42}$-0.6-0.42, where the negative value means the polarity of the circular dichroism can also be tuned. This work deepens the understanding of angular-dependent chirality in metamaterials and expands the potential for terahertz polarization optoelectronic applications.

11.
Cancer Med ; 8(9): 4359-4369, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31210005

RESUMO

BACKGROUND: Cancer-specific autoantibodies found in serum of cancer patients have been characterized as potential predictors of the high risk of recurrence and treatment response. The objective of this study is to investigate the clinical utility of serum O-6-methylguanine-DNA methyltransferase (MGMT) autoantibodies as novel biomarkers for prediction of recurrence and treatment response for glioma through MGMT peptides microarray. METHODS: A total of 201 serum samples of glioma patients with various WHO grade and 311 serum samples of healthy donors were examined for the detection of MGMT autoantibodies by peptides microarray. The clinical value of MGMT autoantibodies was studied through univariable and multivariable analyses. RESULTS: Autoantibodies to MGMT peptides were detected in sera from glioma patients and five highly responsive autoantibodies to peptides were identified in the glioma group. The positive rate of MGMT autoantibody to 20 peptides in glioma groups is compared with healthy individuals, the positive rate of MGMT-02 (45%), MGMT-04 (27%), MGMT-07 (21%), MGMT-10 (13%), and MGMT-18 (24%) were significantly elevated in patients with glioma. MGMT autoantibody and its protein expression exhibited a significant correlation. The levels of MGMT autoantibodies decreased on the 30th day after operation, reaching preoperative levels, similar to those when tumor recurrence developed. Univariable and multivariable analyses revealed that the only preoperative autoantibodies to MGMT-02 peptide were independently correlated with recurrence-free survival. Preoperative seropositive patients were more likely than seronegative patients to have shorter recurrence times and to be resistant to chemoradiotherapy or chemotherapy with temozolomide. CONCLUSION: Monitoring the levels of preoperative serum autoantibodies to MGMT-02 peptide was useful for predicting patients at high risk of recurrence and treatment response.


Assuntos
Autoanticorpos/sangue , Neoplasias Encefálicas/cirurgia , Metilases de Modificação do DNA/imunologia , Enzimas Reparadoras do DNA/imunologia , Glioma/cirurgia , Proteínas Supressoras de Tumor/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/sangue , Neoplasias Encefálicas/imunologia , Estudos de Casos e Controles , Metilases de Modificação do DNA/química , Enzimas Reparadoras do DNA/química , Feminino , Regulação Neoplásica da Expressão Gênica , Glioma/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Peptídeos/imunologia , Análise de Sobrevida , Resultado do Tratamento , Proteínas Supressoras de Tumor/química , Adulto Jovem
12.
J Clin Lab Anal ; 33(7): e22952, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31169949

RESUMO

BACKGROUND: Circular RNAs (circRNAs) are a novel group of RNAs and play essential roles in cancers. However, the expression profiles of circRNAs in human colorectal cancer (CRC) are largely unclear. METHODS: The differentially expressed circRNAs, mRNAs, and microRNAs (miRNAs) between CRC tissues and paired adjacent normal tissues were first screened. Then, gene ontology and pathway analyses were performed to predict the possible functions. In addition, we identified the differentially expressed circRNAs in CRC correlated with Krüppel-like factor 4 (KLF4) and validated their expression levels in CRC tissues. Finally, the correlations between hsa_circ_0142527 expression levels and clinicopathological features of patients with CRC were also analyzed. RESULTS: After filtered 4735 circRNAs by RNA deep sequencing, 67 differentially expressed circRNAs (fold change >2.0, P < 0.05) were selected. The top two pathways were cell cycle and other glycan degradation. Hsa_circ_0142527 and KLF4 mRNA were significantly lower expressed in CRC tissues in both training and confirm groups and have high positive correlation (r = 0.754). We further found that the expression levels of hsa_circ_0142527 were significantly associated with age (P = 0.004), differentiation (P = 0.008), invasion (P = 0.029), distal metastasis (P = 0.004), TNM stage (P = 0.005), and carcinoembryonic antigen (CEA; P = 0.037). CONCLUSIONS: The circRNA expression profile of CRC provided new clues for understanding the occurrence of CRC. Hsa_circ_0142527 may be served as a potential biomarker for the diagnosis of CRC.


Assuntos
Neoplasias Colorretais/genética , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , RNA Circular/genética , Análise de Sequência de RNA , Sequência de Bases , Neoplasias Colorretais/patologia , Regulação para Baixo/genética , Feminino , Ontologia Genética , Humanos , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Masculino , Pessoa de Meia-Idade , RNA Circular/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reprodutibilidade dos Testes , Regulação para Cima/genética
13.
J Clin Ultrasound ; 47(1): 55-58, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30264460

RESUMO

RATIONALE: Ventricular septal dissecting aneurysms are rarely caused by congenital coronary artery fistulas. PATIENT CONCERNS: We present a rare case of ventricular septal dissecting aneurysm that resulted from a congenital coronary artery fistula in a 41-year-old female patient with the complaint of chest pain. DIAGNOSIS: Ventricular septal dissecting aneurysm resulting from a right coronary artery fistula. INTERVENTIONS: The patient was advised to receive transcatheter interventional therapy in the department of cardiology. OUTCOMES: It was difficult for the cardiac catheter to reach the orifice of fistula due to the long and circuitous nature of the right coronary artery, which ultimately resulted in abandoning interventional fistula occlusion therapy. The patient finally decided to undergo surgical treatment in Shanghai and the symptoms have been markedly improved after hemodynamic correction. LESSONS: The right coronary artery was the dominant vessel and the fistula was located in the distal part of the posterior descending branch of right coronary artery. Hence, transcatheter closure was appropriate; however, due to the fact that right coronary artery was too long and circuitous, the length of cardiac catheter was relatively insufficient. For this reason, a comprehensive and careful assessment before the operation is necessary.


Assuntos
Dissecção Aórtica/etiologia , Anomalias dos Vasos Coronários/complicações , Fístula/complicações , Comunicação Interventricular/etiologia , Adulto , Dissecção Aórtica/diagnóstico por imagem , Dissecção Aórtica/cirurgia , Anomalias dos Vasos Coronários/diagnóstico por imagem , Anomalias dos Vasos Coronários/cirurgia , Feminino , Fístula/congênito , Fístula/diagnóstico por imagem , Fístula/cirurgia , Comunicação Interventricular/diagnóstico por imagem , Comunicação Interventricular/cirurgia , Humanos , Ultrassonografia
14.
J Phys Condens Matter ; 31(8): 085301, 2019 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-30557863

RESUMO

We give direct evidence of both surface plasmon resonance (SPR) and localized waveguide resonance (LWR) contribution to the extraordinary optical transmission in complementary metamaterials. Strong coupling between SPR and LWR are also observed with clear evidence of Rabi splitting and anti-crossing phenomena. The splitting introduces sharp phase shift, which in turn enhances group velocity delay by the incident angle without geometric parameter change. The results not only clarify SPR and LWR effects in the extraordinary optical transmission, but also provide a novel route to control light-metamaterial interaction by angular modulation for on-chip slow light devices.

15.
Nanoscale ; 10(25): 11881-11893, 2018 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-29897080

RESUMO

Excellent PEC efficiency, good reusability and the super stability of trap-like SnS2/TiO2 nanotube arrays (NTs)-based photoanodes are reported. Specifically, the SnS2/TiO2-180 °C (ST-180) photoanode exhibited the highest photocurrent density (1.05 mA cm-2) and an optimal η (0.73%) at 0.5 V (vs. SCE) under simulated light irradiation (AM 1.5G), which are 4.6 and 3.8 times higher than those of pure TiO2 NTs (0.23 mA cm-2 and 0.19%). The IPCE values of ST-180 can reach 21.5% (365 nm) and 13.8% (420 nm), which are much higher than those of pure TiO2 NTs (10.6% at 365 nm and 0.8% at 420 nm). The APCE values of the pure TiO2 NTs photoelectrode are 12.8% (365 nm) and 1.1% (420 nm), while the ST-180 values are 22.3% and 14.2%, respectively. Furthermore, the generation rates of H2 and O2 for the ST-180 photoanode are 47.2 and 23.1 µmol cm-2 h-1 at 0.5 V under AM 1.5G, corresponding to faradaic efficiencies of around 80.1% and 78.3%, respectively. In short, the high-efficiency PEC water splitting performance of this SnS2/TiO2 photoanode results from the enhanced light harvesting ability of the trap-like SnS2 structure, accelerated carrier transportation properties of TiO2 NTs, and effective carrier separation of the type-II heterojunction structure. This work may offer a combinatorial strategy for the preparation of heterojunction structures with high PEC performance and can be a model structure for similar photoanode materials.

16.
Ultrasonics ; 71: 143-151, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27344606

RESUMO

Ultrasonic disintegration is a very promising sludge pretreatment method that leverages the cavitation effect to produce extreme physical environments characterized by high temperatures and high pressures. This process disintegrates sludge structure features, promotes sludge dewatering, and aides resource recovery. This paper presents a newly designed continuous ultrasonic sludge treatment device. The characteristics of the ultrasonic wave propagated in the activated sludge were simulated, with the results showing that at lower frequencies, the acoustic pressure energy distribution exhibits more local concentrations, whereas at 80kHz, the energy distribution is relatively uniform as a result of the interference of standing waves. Subsequently, activated sludge was ultrasonically treated with different exposure times and frequencies. The sludge's capillary suction time, particle size, and moisture content were measured. The results showed different trends for each of the investigated parameters. The dewatering performance was best when the exposure time was 5-10s. Finally, different substances were added to the ultrasonically treated sludge to analyze the effects of ultrasonic treatment on anaerobic digestion. The gas production rate was higher when glucose was the added substance than it was for yeast. The highest total concentration of produced gas, including both hydrogen and methane, was 34% for an ultrasonic input power of 200W at a 25kHz frequency, an exposure time of 20s, and with 30g of added glucose. The gas production rate was found to be higher at the lower frequency when frequency was the only variable. These experiments demonstrate that ultrasonic treatment can change the structure of sludge particles and the moisture content of the sludge, improving sludge dewatering performance. Furthermore, after ultrasonic treatment can improve gas production.

17.
Environ Sci Pollut Res Int ; 21(3): 1859-1874, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23990259

RESUMO

The adsorption of Cr(VI) and As(III) by amino-functionalized SBA-15 (NH2-SBA-15) from single and binary systems were investigated in this work. The effects of pH and temperature on the adsorption of NH2-SBA-15 were studied. Adsorption kinetics, isotherm model, and thermodynamics were studied to analyze the experimental data. pH 2 was the optimum condition for the adsorption of Cr(VI) and pH 4 for As(III) adsorption. Increasing temperature had a positive effect on the removal of both Cr(VI) and As(III). The Freundlich isotherm model can depict the adsorption process best. The pseudo-second-order kinetic model fitted well with the kinetic data of Cr(VI) and As(III) in the single-component system. In the binary system, the adsorption of As(III) by NH2-SBA-15 was slightly enhanced with the presence of Cr(VI); however, As(III) had no obvious effect on the removal of Cr(VI). Regeneration experiments indicated that 0.1 mol/L NaHCO3 was an efficient desorbent for the recovery of Cr(VI) and As(III) from NH2-SBA-15; the desorption rates for Cr(VI) and As(III) were 91.6 and 33.59 %, respectively. After five recycling cycles, the removal rates were 88 and 7 % for Cr(VI) and As(III) adsorption by NH2-SBA-15, respectively.


Assuntos
Arsenitos/química , Cromo/química , Dióxido de Silício/química , Poluentes Químicos da Água/química , Adsorção , Arsenitos/análise , Cromo/análise , Concentração de Íons de Hidrogênio , Cinética , Porosidade , Temperatura , Termodinâmica , Poluentes Químicos da Água/análise , Purificação da Água/métodos
18.
Environ Sci Pollut Res Int ; 20(4): 2210-9, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22791350

RESUMO

This study evaluates the behavior of coconut charcoal (AC) to adsorb Cr(VI), As(III), and Ni(II) in mono- and multicomponent (binary and ternary) systems. Batch experiments were carried out for mono- and multicomponent systems with varying metal ion concentrations to investigate the competitive adsorption characteristics. The adsorption kinetics followed the mechanism of the pseudo-second-order equation in both single and binary systems, indicating chemical sorption as the rate-limiting step of adsorption mechanism. Equilibrium studies showed that the adsorption of Cr(VI), As(III), and Ni(II) followed the Langmuir model and maximum adsorption capacities were found to be 5.257, 0.042, and 1.748 mg/g, respectively. In multicomponent system, As(III) and Ni(II) adsorption competed intensely, while Cr(VI) adsorption was much less affected by competition than As(III) and Ni(II). With the presence of Cr(VI), the adsorption capacities of As(III) and Ni(II) on AC were higher than those in single system and the metal sorption followed the order of Ni(II) > As(III) > Cr(VI). The results from the sequential adsorption-desorption cycles showed that AC adsorbent held good desorption and reusability.


Assuntos
Arsênio/química , Carvão Vegetal/química , Cromo/química , Cocos/química , Níquel/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Ligação Competitiva , Frutas/química , Concentração de Íons de Hidrogênio , Cinética , Modelos Químicos
19.
Phytochem Anal ; 19(5): 438-43, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18435530

RESUMO

Two novel sorghumol acyl esters, sorghumol 3-O-Z-p-coumarate and sorghumol 3-O-E-p-coumarate, and a novel alkaloid, anoectochine, were isolated from the whole plants of Anoectochilus roxburghii along with one known triterpenoid, sorghumol. Their structures were established by their detailed spectral studies, including two-dimensional NMR ((1)H-(1)H COSY, HSQC and HMBC).


Assuntos
Orchidaceae/química , Triterpenos/isolamento & purificação , Ésteres , Espectroscopia de Ressonância Magnética , Espectrometria de Massas por Ionização por Electrospray , Espectrofotometria Ultravioleta
20.
Zhong Yao Cai ; 30(7): 797-800, 2007 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-17944188

RESUMO

OBJECTIVE: To study the chemical constituents in the whole herb of Anoectochiluts roxburghii (Wall) Lindl. METHOD: The chemical constituents were isolated by various column chromatographic methods and structurally elucidated by IR, NMR and MS evidences. RESULT: Fourteen compounds were obtained and there into ten were identified as beta-sitosterol(2), ferulic acid(3), oleanolic acid(6), lanosterol(7), p-hydroxybenzaldehyde(8), 3-methoxyl-p-hydroxybenzaldehlde(9), daucosterol(10),3',4',7-trimethoxy-3, 5-dihydroxyflavone(11), isorhamnetin-3-O-beta-D-rutinoside(12) and rutin(13). CONCLUSION: Compounds 6,7,9 and 11 from genera Anoeetochilus were isolated for the first time.


Assuntos
Flavonas/isolamento & purificação , Lanosterol/isolamento & purificação , Ácido Oleanólico/isolamento & purificação , Orchidaceae/química , Plantas Medicinais/química , Ácidos Cumáricos/química , Ácidos Cumáricos/isolamento & purificação , Flavonas/química , Lanosterol/química , Estrutura Molecular , Ácido Oleanólico/química , Sitosteroides/química , Sitosteroides/isolamento & purificação , Espectrofotometria Ultravioleta/métodos
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