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1.
Small ; : e2400390, 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38778736

RESUMEN

Gel electrolytes are gaining attention for rechargeable Zn-ion batteries because of their high safety, high flexibility, and excellent comprehensive electrochemical performances. However, current gel electrolytes still perform at mediocre levels due to incomplete Zn salts dissociation and side reactions. Herein, an electrostatic-induced dual-salt strategy is proposed to upgrade gel electrolytes to tackle intrinsic issues of Zn metal anodes. The competitive coordination mechanism driven by electrostatic repulsion and steric hindrance of dual anions promotes zinc salt dissociation at low lithium salt addition levels, improving ion transport and mechanical properties of gel electrolytes. Li+ ions and gel components coordinate with H2O, reducing active H2O molecules and inhibiting associated side reactions. The dual-salt gel electrolyte enables excellent reversibility of Zn anodes at both room and low temperatures. Zn||Polyaniline cells using the dual-salt gel electrolyte exhibit a high discharge capacity of 180 mAh g-1 and long-term cycling stability over 180 cycles at -20 °C. The dual-salt strategy offers a cost-effective approach to improving gel electrolytes for high-performance flexible Zn-ion batteries.

2.
Neurochem Res ; 45(2): 278-294, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31792665

RESUMEN

Cerebral ischemia-reperfusion injury is a complex pathophysiological process. Poly(ADP-ribose) (PAR) polymerase-1 (PARP-1)/apoptosis-inducing factor (AIF) signaling pathway-mediated apoptosis is one of the non-caspase-dependent cell death programs that are widely present in neurological diseases such as stroke. In our study, we aimed to conduct further research on the effects of Gualou Guizhi decoction (GLGZD) on the PARP-1/AIF signaling pathway in cell apoptosis after ischemia-reperfusion injury caused by middle cerebral artery occlusion (MCAO). The results showed that GLGZD administration for 7 days significantly ameliorated MCAO-induced neurological damage, limb paralysis and the pathological state of the ischemic cortex. GLGZD exerted its effects by significantly reducing the volume of ischemic cerebral infarction, increasing the number of Nissl-positive cells, and reducing neuronal apoptosis. Furthermore, Western blot analysis showed that GLGZD significantly inhibited the total protein expression of PARP-1, PAR, AIF and endonuclease G (Endo G) in the ischemic cortex and significantly increased the total protein expression of heat-shock protein 70 (Hsp70). On the one hand, the expression of PARP-1, AIF and Endo G protein in the nucleus significantly decreased while the expression of PAR nucleoprotein significantly upregulated. On the other hand, compared with the MCAO model group, the GLGZD-treated group showed a significantly reduced protein expression of PAR in mitochondria and significantly increased protein expression of mitochondrial AIF and Endo G. It was concluded that GLGZD had good therapeutic effects in MCAO model rats. These effects were closely related to GLGZD-mediated inhibition of ischemia-induced neuronal apoptosis by regulation of protein expression and translocation in the PARP-1/AIF signaling pathway.


Asunto(s)
Apoptosis/efectos de los fármacos , Medicamentos Herbarios Chinos/uso terapéutico , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Fármacos Neuroprotectores/uso terapéutico , Daño por Reperfusión/tratamiento farmacológico , Transducción de Señal/efectos de los fármacos , Animales , Factor Inductor de la Apoptosis/metabolismo , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Medicamentos Herbarios Chinos/química , Infarto de la Arteria Cerebral Media/metabolismo , Infarto de la Arteria Cerebral Media/patología , Masculino , Fármacos Neuroprotectores/química , Poli(ADP-Ribosa) Polimerasa-1/metabolismo , Ratas Sprague-Dawley , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología
3.
Sensors (Basel) ; 19(15)2019 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-31390739

RESUMEN

The rehabilitation robot is an application of robotic technology for people with limb disabilities. This paper investigates a new applicable and effective sitting/lying lower limb rehabilitation robot (the LLR-Ro). In order to improve the patient's training initiative and accelerate the rehabilitation process, a new motion intention acquisition method based on static torque sensors is proposed. This motion intention acquisition method is established through the dynamics modeling of human-machine coordination, which is built on the basis of Lagrangian equations. Combined with the static torque sensors installed on the mechanism leg joint axis, the LLR-Ro can obtain the active force from the patient's leg. Based on the variation of the patient's active force and the kinematic functional relationship of the patient's leg end point, the patient motion intention is obtained and used in the proposed active rehabilitation training method. The simulation experiment demonstrates the correctness of mechanism leg dynamics equations through ADAMS software and MATLAB software. The calibration experiment of the joint torque sensors' combining limit range filter with an average value filter provides the hardware support for active rehabilitation training. The consecutive variation of the torque sensors from just the mechanism leg weight, as well as both the mechanism leg and the patient leg weights, obtains the feasibility of lower limb motion intention acquisition.


Asunto(s)
Extremidad Inferior/fisiología , Robótica , Algoritmos , Fenómenos Biomecánicos , Diseño de Equipo , Hemiplejía/rehabilitación , Humanos
4.
Nanotechnology ; 29(12): 125602, 2018 Mar 23.
Artículo en Inglés | MEDLINE | ID: mdl-29311422

RESUMEN

Rutile TiO2 are widely used for applications of coatings, cosmetics, photoelectric devices and so on. However, effective control of well-defined morphology, size and composition of rutile TiO2 nanoparticles from agglomeration has always been a challenge. A new synthesis strategy was proposed to prepare rutile TiO2 with controllable morphology varied from flower-like structures to single-separated nanorods. The ß-FeOOH nanoparticles were generated by the hydrolysis of FeCl3 solution and could prevent the aggregation of TiO2 nanocrystals at early stages of the reaction; thus, could control the morphology of rutile nanoparticles. The morphology of rutile TiO2 nanoparticles could be controllably regulated from flower-like structures to individually separated nanorods. Meanwhile, the preformed ß-FeOOH also played a role of dopant. Fe ions were substitutionally doped into the bulk lattice of TiO2 nanocrystals and reduced the bandgap, which extended the solar radiation absorption range of rutile TiO2. The prepared TiO2 may be suitable for novel UV-blue light shielding agents and many other applications in photoelectric devices, photocatalysis, and so on due to its small size, unprecedented discrete rod-like structure and unique UV-vis light permeability.

5.
Front Surg ; 10: 1106137, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36843997

RESUMEN

Introduction: The objective of our study was to construct a preoperative prediction nomogram for the classical variant of papillary thyroid carcinoma (CVPTC) patients with a solitary lesion based on demographic and ultrasonographic parameters that can quantify the individual probability of high-volume (>5) lymph node metastasis (HVLNM). Materials and methods: In this study, a total of 626 patients with CVPTC from December 2017 to November 2022 were reviewed. Their demographic and ultrasonographic features at baseline were collected and analyzed using univariate and multivariate analyses. Significant factors after the multivariate analysis were incorporated into a nomogram for predicting HVLNM. A validation set from the last 6 months of the study period was conducted to evaluate the model performance. Results: Male sex, tumor size >10 mm, extrathyroidal extension (ETE), and capsular contact >50% were independent risk factors for HVLNM, whereas middle and old age were significant protective factors. The area under the curve (AUC) was 0.842 in the training and 0.875 in the validation set. Conclusions: The preoperative nomogram can help tailor the management strategy to the individual patient. Additionally, more vigilant and aggressive measures may benefit patients at risk of HVLNM.

6.
Front Biosci (Landmark Ed) ; 27(10): 296, 2022 10 31.
Artículo en Inglés | MEDLINE | ID: mdl-36336865

RESUMEN

BACKGROUND: Endoplasmic reticulum stress (ERS) is a key part of the apoptotic cascade that is initiated after cerebral ischemia-reperfusion injury and is very important for research on poststroke rehabilitation. In addition, the unfolded protein response (UPR) plays an important role in ERS because it activates downstream apoptotic signal transduction and induces apoptosis through the glucose-regulated protein 78 (GRP78)/protein kinase R (PKR)-like ER kinase (PERK)/activating transcription factor 4 (ATF4) pathway. The Gua Lou Gui Zhi Decoction (GLGZD) ameliorated neuronal apoptosis of ischemia-reperfusion injury caused by middle cerebral artery occlusion (MCAO) had been proved in our previous study. The present study aims to underly the regulatory ability of GLGZD in ERS-induced apoptosis mediated by the GRP78/PERK/ATF4 pathway. METHODS: GLGZD was analyzed by HPLC. The effects of GLGZD were obversed on MCAO-induced ischemic rats. The cerebral infarct volume was detected by 2,3,5-Triphenyl-2H-Tetrazolium Chloride (TTC) Staining. Terminal Deoxynucleotidyl Transferase-Mediated dUTP-Biotin Nick End Labeling (TUNEL) were used to detect apoptosis. Transmission Electron Microscopy (TEM), Ca2+ levels and reactive oxygen species (ROS) detection were used to determine the function of endoplasmic reticulum. The GRP78/PERK/ATF4 signaling pathway was assessed by western blotting and immunohistochemistry. RESULTS: Our results showed that GLGZD exerted its effects on ischemia-reperfusion injury by significantly promoting the restoration of the quantity and morphology of the rough ER and reducing the neuronal apoptosis rate in the ischemic cortex. Moreover, both of the intracellular ROS and Ca2+ levels in ischemic cortical cells were found significantly reduced by GLGZD. The GLGZD-treated group showed increased levels of phosphorylation in both of PERK and eukaryotic translation initiation factor 2α (eIF2α), activation of cysteinyl aspartate-specific proteinase-3 (Caspase-3), upregulation of the total protein levels of sarcoplasmic/endoplasmic Ca2+ ATPase 2α (SERCA 2α) and B-cell leukemia/lymphoma gene 2 (Bcl-2). CONCLUSIONS: These findings suggest that GLGZD reduces oxidative stress-induced injury and promotes a dynamic calcium balance, thereby inhibiting ERS and exerting an antiapoptotic effect on neuronal ischemic injury, which are closely related to the activation of GRP78/PERK/ATF4 signaling pathway.


Asunto(s)
Estrés del Retículo Endoplásmico , Daño por Reperfusión , Animales , Ratas , Factor de Transcripción Activador 4/genética , Factor de Transcripción Activador 4/metabolismo , Especies Reactivas de Oxígeno , Calcio , Daño por Reperfusión/tratamiento farmacológico , Daño por Reperfusión/metabolismo , Apoptosis
7.
World J Clin Cases ; 10(17): 5825-5832, 2022 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-35979116

RESUMEN

BACKGROUND: Mycosis fungoides (MF) is a form of lymphoma derived from heterogeneous T cells, and eyelid involvement is extremely rare. The common methods to treat eyelid involvement are radiotherapy and chemotherapy, but their efficacies are limited. Herein, we report a case of advanced-stage MF eyelid involvement, propose ultrasound (US)-guided microwave ablation (MWA) therapy and present a literature review. CASE SUMMARY: A male patient was admitted to our hospital in June 2018 and diagnosed with MF via radiological and histopathological examinations. The patient's condition was not well controlled by various conventional chemotherapies. US-guided MWA was performed to relieve the patient's symptoms and improve his quality of life, showing satisfactory efficacy. CONCLUSION: Eyelid involvement is one of the most troublesome clinical problems for advanced-stage MF patients. This is the first report on the use of US-guided MWA as a palliative therapy for MF eyelid involvement; the treatment successfully relieved the patient's clinical symptoms and reduced his anxiety behaviours. Our study sheds new light on methods for improving the clinical management of eyelid involvement in MF.

8.
Commun Chem ; 4(1): 97, 2021 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-36697588

RESUMEN

Organic microlasers hold great potentials in fabricating on-chip sensors for integrated photonic circuits due to their chemical versatility and reactivity. However, chemical vapor detection is still challenging for organic microlaser sensors, as it requires not only optical gain and self-assembly capability, but also rapid response to stimuli and long-term stability under high excitation power. In this work, a new laser dye 4,7-bis(9-octyl-7-(4-(octyloxy)phenyl)-9H-carbazol-2-yl)benzo[c][1,2,5]thiadiazole (BPCBT) is designed and synthesized, which self-assembles into microwires showing strong intramolecular charge transfer (ICT) photoluminescence with >80% quantum efficiency. It enables the lasing from BPCBT microwires under a low threshold of 16 µJ·mm-2·pulse-1 with significantly improved stability over conventional organic microlasers. The stimulated emission amplifies the fluorescence change in the BPCBT microwires under chemical vapors including various acid, acetone, and ethanol vapors, indicating high sensitivity and high selectivity of organic microlaser sensors desirable for compact sensor arrays in integrated photonics.

9.
Front Endocrinol (Lausanne) ; 12: 752822, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34630337

RESUMEN

Purpose: To investigate whether ablating the aspiration needle tract could improve the safety and efficacy of ultrasound-guided microwave ablation (MWA) for predominantly cystic thyroid nodules. Materials and Methods: This retrospective study evaluated 41 predominantly cystic thyroid nodules that underwent MWA between June 2017 and August 2019. The nodules were stratified by different procedures into two groups: the aspiration needle tract was ablated before cyst fluid aspiration and MWA when treating 26 nodules in Group A, while the other 15 nodules in Group B underwent MWA directly after cyst fluid aspiration. Baseline characteristics, intervention time, hospital stays, nodules with intraoperative intracystic hemorrhage, and postoperative complications were compared between the two groups. Volume, volume reduction rate (VRR), compressive score (CS), and aesthetic score (AS) were evaluated during follow-up. Results: Both groups achieved decreases in volume, CS, and AS, as well as an increase in VRR. The volumes and VRRs in Group A at 1, 3, 6, and 12 months were significantly smaller and greater than those in Group B (p < 0.001). The incidence of intraoperative intracystic hemorrhage in Group A was significantly lower than that in Group B (p=0.035). Compared to Group B, hospital stays were much shorter in Group A (p=0.040). There were no significant differences in intervention time, cystic fluid volume or postoperative complications. Conclusion: Aspiration needle tract ablation dramatically reduces the incidence of intraoperative intracystic hemorrhage and markedly improves the efficacy of MWA for predominantly cystic thyroid nodules.


Asunto(s)
Biopsia con Aguja Fina , Microondas , Ablación por Radiofrecuencia/métodos , Nódulo Tiroideo/terapia , Adulto , Anciano , Quistes/patología , Femenino , Hemorragia/complicaciones , Humanos , Tiempo de Internación , Masculino , Persona de Mediana Edad , Tempo Operativo , Complicaciones Posoperatorias/epidemiología , Estudios Retrospectivos , Nódulo Tiroideo/diagnóstico , Resultado del Tratamiento , Ultrasonografía Intervencional , Adulto Joven
10.
Int J Med Mushrooms ; 23(8): 25-37, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34587423

RESUMEN

Continuous monoculture can increase plant morbidity and reduce crop yields. However, the Ganoderma lucidum mushroom possesses unique nutrient acquisition methods and displays an altered response to the generation of reactive oxygen species (ROS). The effects of continuous cropping on G. lucidum remain unclear. Here, we investigated the effects of consecutive monoculture soil on the yield, bioactive components, antioxidant properties, nutrient metabolism, and enzyme activity of G. lucidum. The results showed no significant differences in terms of yield between the control check and treatment groups after 2 years. However, the content of polysaccharides and triterpenoids after 2 years of treatment and the content of total phenols and flavonoids after 3 years of treatment significantly increased. Moreover, the antioxidant activity (AOA) of the polysaccharides under consecutive monoculture soil treatments also significantly increased. These differences were caused by changes in nutrient metabolism and the activities of antioxidant and ligninolytic enzymes. Under continuous monoculture soil treatment, the content of reducing sugars, water-soluble sugars, free amino acids, and water-soluble proteins significantly increased. The activities of superoxide dismutase, manganese peroxidase, and lignin peroxidase increased with the time of continuous monoculture, while the activities of peroxidase, catalase, and laccase decreased. The increase in ligninolytic enzymes was postulated to mediate the ROS scavenging ability of G. lucidum. In conclusion, continuous cropping soil could increase the levels of bioactive components and AOAs of G. lucidum.


Asunto(s)
Agaricales , Reishi , Antioxidantes/análisis , Flavonoides , Suelo
11.
Food Chem Toxicol ; 150: 112073, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33631283

RESUMEN

Ganoderma lucidum exhibits pronounced anti-inflammatory effects, polysaccharides and triterpenoids are regarded as major constituents displaying the anti-inflammatory activities, whether sterols contribute to this activity remains unclear. Herein Ganoderma lucidum sterols (GLS) were innovatively isolated by a single-step procedure, the profile of GLS was characterized by HPLC-ELSD and shown similar to that of sterols separated by a traditional method, but much higher in content. Furthermore, GLS inhibited inflammation in macrophages by significantly attenuating LPS-induced cell polarization as well as releases and mRNA expressions of pro-inflammatory mediators NO, TNF-α, IL-1ß and IL-6. Moreover, the anti-inflammatory activity of GLS was mediated by MAPK and NF-κB pathways, GLS suppressed MAPK pathways by blocking phosphorylation of p38 but not ERK and JNK, which is complementary with inhibitory effects of Ganoderma polysaccharides and triterpenes on JNK and ERK, indicating Ganoderma sterols may exert synergistic anti-inflammatory effect with polysaccharides and triterpenes. GLS also inhibited NF-κB pathways by restraining phosphorylation and degradation of IκB-α and blocking phosphorylation of NF-κB p65. Molecular docking confirmed that sterols of GLS were directly bound to active sites of p38 and p65 to suppress their activation. Therefore, our findings suggest GLS as natural and safe anti-inflammatory agents to prevent and treat inflammatory diseases.


Asunto(s)
Inflamación/inducido químicamente , Lipopolisacáridos/toxicidad , FN-kappa B/metabolismo , Extractos Vegetales/farmacología , Reishi , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Animales , Antiinflamatorios , Supervivencia Celular/efectos de los fármacos , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Inflamación/prevención & control , Ratones , FN-kappa B/genética , Óxido Nítrico , Óxido Nítrico Sintasa de Tipo II/genética , Óxido Nítrico Sintasa de Tipo II/metabolismo , Fitosteroles/química , Fitosteroles/farmacología , Fitoterapia , Extractos Vegetales/química , Células RAW 264.7 , ARN Mensajero/genética , ARN Mensajero/metabolismo
12.
Clin Hemorheol Microcirc ; 78(2): 117-126, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33554894

RESUMEN

Integrated analysis of accumulated data is an effective way to obtain reliable potential diagnostic molecular of cervical lymph node metastases (LNM) in papillary thyroid carcinoma (PTC). The benefits of prophylactic lymph node dissection (PLND) for these clinically node-negative (cN0) patients remained considerable controversies. Hence, elucidation of the mechanisms of LNM and exploration of potential biomarkers and prognostic indicators are essential for accurate diagnosis of LNM in PTC patients. Up to date, advanced microarray and bioinformatics analysis have advanced an understanding of the molecular mechanisms of disease occurrence and development, which are necessary to explore genetic changes and identify potential diagnostic biomarkers. In present study, we performed a comprehensive analysis of the differential expression, biological functions, and interactions of LNM-related genes. Two publicly available microarray datasets GSE60542 and GSE129562 were available from Gene Expression Omnibus (GEO) database. Differentially expressed genes between clinically node-positive (cN1) and cN0 PTC samples were screened by an integrated analysis of multiple gene expression profile after gene reannotation and batch normalization. Our results identified 48 differentially expressed genes (DEGs) genetically associated with LNM in PTC patients. Gene ontology (GO) analyses revealed the changes in the modules were mostly enriched in the regulation of MHC class II receptor activity, the immune receptor activity, and the peptide antigen binding. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis of DEGs displayed the intestinal immune network for IgA production, staphylococcus aureus infection, and cell adhesion molecules (CAMs). To screen core genes related to LNM of PTC from the protein-protein interaction network, top 10 hub genes were identified with highest scores. Our results help us understand the exact mechanisms underlying the metastasis of cervical LNM in PTC tissues and pave an avenue for the progress of precise medicine for individual patients.


Asunto(s)
Biomarcadores de Tumor/metabolismo , Biología Computacional/métodos , Ganglios Linfáticos/patología , Metástasis Linfática/patología , Cáncer Papilar Tiroideo/patología , Neoplasias de la Tiroides/patología , Biomarcadores de Tumor/genética , Humanos , Ganglios Linfáticos/metabolismo , Cuello , Pronóstico , Cáncer Papilar Tiroideo/genética , Cáncer Papilar Tiroideo/metabolismo , Neoplasias de la Tiroides/genética , Neoplasias de la Tiroides/metabolismo
13.
J Comput Biol ; 28(1): 99-114, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-32790501

RESUMEN

Although the incidence of thyroid carcinoma is reported to be the highest among malignancies of endocrine system, its diagnosis is still unsatisfactory. This study sought to explore the key DNA methylation-driven genes in the development of papillary thyroid carcinoma (PTC) via a bioinformatic analysis based on the Cancer Genome Atlas (TCGA) database and was validated using the Gene Expression Omnibus (GEO) database. The level 3 DNA methylation, mRNA expression, and clinical data of 499 patients with PTC were obtained from the TCGA database. The R package LIMMA, edgeR, and MethylMix were applied to explore the DNA methylation-driven genes in PTC. The ConsensusPathDB software, DAVID, and STRING databases were used for Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses, as well as protein/protein interaction network construction individually. To verify the result, the explored genes were validated using GSE97466 data set retrieved from the GEO database. Fifty-seven (57) methylation-driven genes were detected via MethylMix based on a beta mixture model that compared the DNA methylation state of tumor tissues with that of the normal tissues. Eventually, three genes (TNFRSF1A, CLDN1, and CASP1) were identified to be the most potential biomarkers for the diagnosis or treatment of PTC. These results suggest the crucial roles of TNFRSF1A, CLDN1, and CASP1 in the tumorigenesis of PTC and provide a vital bioinformatic basis for further experimental validations and clinical applications.


Asunto(s)
Biomarcadores de Tumor/genética , Metilación de ADN , Cáncer Papilar Tiroideo/genética , Neoplasias de la Tiroides/genética , Caspasa 1/genética , Claudina-1/genética , Bases de Datos Genéticas , Humanos , Receptores del Factor de Necrosis Tumoral/genética
14.
Glob Chall ; 4(11): 2000002, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33163224

RESUMEN

Transition metal orthovanadates are emerging 2D materials for promising electrochemical energy storage applications. Facile hydrothermal method for nanocrystalline indium vanadate (InVO4) semiconducting materials' fabrication is economical because of its direct chemical synthesis. X-ray diffraction studies, field emission scanning electron microscope (SEM) images, transmission electron microscopy (TEM), and photoelectron X-ray spectrum are used to describe the semiconductor materials as synthesized. InVO4 microspheres have attracted a lot of attention in the energy and environmental sector. These microsphere-derived semiconductor materials are recognized to offer the advantages of their large surface area, tunable pore sizes, enhanced light absorption, efficient carrier (electron-hole) separation, superior electronic and optical behavior, and high durability. From the results of SEM and TEM, InVO4 shows a microsphere construction with a mixture of nanosized particles. Diffuse reflectance UV-visible measurements are used to determine the bandgap, and it is found to be 2.1 eV for InVO4. The electrochemical analysis reveals a superior performance of the pseudocapacitor with hydrothermally derived microspheres of InVO4. Alongside an improved pseudocapacity, developed after 4000 cycles, it has excellent cycling stability with a retention of ≈94% of its original specific capacitance efficiency.

15.
RSC Adv ; 9(20): 11385-11395, 2019 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-35520245

RESUMEN

Density functional theory (DFT) and measurements of rate are used to provide evidence for the rate determining step (RDS) and requirements of the active site for CH4 combustion on Pd-Pt bimetallic catalysts in five different distinct kinetic regimes. These five regimes exhibit different rate equations for methane combustion due to the reaction rate constants and diverse dominant adsorbed species for these different kinetically relevant steps. Oxygen chemical potential at the Pd-Pt surface was replaced by oxygen pressure, reflecting the kinetic coupling between C-H and O[double bond, length as m-dash]O bond cleavage steps. C-H bond cleavage occurs on different active sites in five of these kinetic regimes, evolving from vacancy-vacancy (*-*) to oxygen-vacancy (O*-*), oxygen-oxygen (O*-O*) site pairs, monolayer Pd-O, and ultimately to oxide bulk with Pd-O site pairs as the oxygen chemical potential increases. It is easier to form a metallic surface at low oxygen pressure, implying minimal O* coverage. The sole kinetically relevant step on uncovered Pd-Pt surfaces for methane combustion is O[double bond, length as m-dash]O bond cleavage. The supply of oxygen is obviously more important than the supply of methane in regime (I). As vacancies become less available on metallic surfaces, C-H bond cleavage occurs via O*-* paired sites, the energy barrier of which is much higher than that on uncovered Pd-Pt surfaces. In this regime (II), O[double bond, length as m-dash]O bond cleavage is still an irreversible process because O* will be consumed by the rapidly formed products of methane dissociation. For the oxygen saturated surfaces in regime (III), C-H bond cleavage occurs on two adjacent adsorbed oxygens that form OH and weak CH3-O bond interactions, resulting in a low activity for methane combustion. On the oxidation surfaces (IV and V), exposed metal atoms and their adjacent exposed lattice oxygen were the active sites, leading to a large decrease in C-H bond cleavage energy barrier, deduced from both experiment and theory. The increase of the metallic oxide thickness (increase of oxygen potential) increases the methane combustion turnover rates on Pd-Pt catalysts.

16.
Chemosphere ; 197: 526-534, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29407814

RESUMEN

As a new member of carbon dots (CDs), Polymer dots (PDs) prepared by hydrothermal treatment of polymers, usually consist of the carbon core and the connected partially degraded polymer chains. This type of CDs might possess aqueous solubility, non-toxicity, excellent stability against photo-bleaching and high visible light activity. In this research, PDs were prepared by a moderate hydrothermal treatment of polyvinyl alcohol, and PDs grafted TiO2 (PDs-TiO2) nanohybrids with TiOC bonds were prepared by a facile in-situ hydrothermal treatment of PDs and Ti (SO4)2. Under visible light irradiation, the PDs-TiO2 demonstrate excellent photocatalytic activity for methyl orange degradation, and the photocatalytic rate constant of PDs-TiO2 is 3.6 and 9.5 times higher than that of pure TiO2 and commercial P25, respectively. In addition, the PDs-TiO2 exhibit good recycle stability under UV-Vis light irradiation. The interfacial TiOC bonds and the π-conjugated structures in PDs-TiO2 can act as the pathways to quickly transfer the excited electrons between PDs and TiO2, therefore contribute to the excellent photocatalytic activity.


Asunto(s)
Procesos Fotoquímicos , Polímeros/química , Titanio/química , Compuestos Azo , Carbono , Catálisis , Luz , Modelos Químicos , Rayos Ultravioleta , Agua/química
17.
Artículo en Inglés | MEDLINE | ID: mdl-29075304

RESUMEN

Gualou Guizhi decoction (GLGZD) is effective for the clinical treatment of limb spasms caused by ischemic stroke, but its underlying mechanism is unclear. Propidium iodide (PI) fluorescence staining, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL), immunohistochemistry, western blot, and real-time qPCR were used to observe the axonal regeneration and neuroprotective effects of GLGZD aqueous extract on organotypic cortical slices exposed to oxygen-glucose deprivation (OGD) and further elucidate the potential mechanisms. Compared with the OGD group, the GLGZD aqueous extract decreased the red PI fluorescence intensity; inhibited neuronal apoptosis; improved the growth of slice axons; upregulated the protein expression of tau and growth-associated protein-43; and decreased protein and mRNA expression of neurite outgrowth inhibitor protein-A (Nogo-A), Nogo receptor 1 (NgR1), ras homolog gene family A (RhoA), rho-associated coiled-coil-containing protein kinase (ROCK), and phosphorylation of collapsin response mediator protein 2 (CRMP2). Our study found that GLGZD had a strong neuroprotective effect on brain slices after OGD injury. GLGZD plays a vital role in promoting axonal remodeling and functional remodeling, which may be related to regulation of the expression of Nogo-A and its receptor NgR1, near the injured axons, inhibition of the Rho-ROCK pathway, and reduction of CRMP2 phosphorylation.

18.
Di Yi Jun Yi Da Xue Xue Bao ; 25(4): 432-4, 2005 Apr.
Artículo en Zh | MEDLINE | ID: mdl-15837648

RESUMEN

A retrospective analysis of 21 cases of Brugada syndrome treated between 1997 and 2004 was conducted to examine the clinical characteristics of these patients and the relations between fever and Brugada syndrome. Of the 21 patients including one female patient, 4 male patents with Brugada syndrome were confirmed to develop ventricular arrhythmias due to febrile disease, suggesting that fever, one of the common causes for triggering cardiac events in Brugada syndrome, should receive due attention in clinical practice.


Asunto(s)
Síndrome de Brugada/etiología , Fiebre/complicaciones , Adulto , Síndrome de Brugada/diagnóstico , Síndrome de Brugada/terapia , Electrocardiografía , Femenino , Humanos , Masculino , Estudios Retrospectivos
19.
Di Yi Jun Yi Da Xue Xue Bao ; 23(11): 1139-42, 2003 Nov.
Artículo en Zh | MEDLINE | ID: mdl-14625171

RESUMEN

OBJECTIVE: To perform PCR-based site-directed mutagenesis of a new SCN5A mutation (K317N) identified in a Chinese family with Brugada syndrome and construct the recombinant expression plasmid pRc/CMV-Hh1 containing the human cardiac sodium channel alpha subunit (hH1), mutant cDNA. METHODS: A pair of primers was designed according to the restricted sites Sse 8387I and Age I of the SCN5A sequence with the mismatches introduced into primers. Mutagenesis was performed in a single-step PCR, and the fragments amplified by PCR containing the mutation site were subcloned into the pRc/CMV-hH1 vector. RESULTS: Sequence analysis confirmed the presence of the desired mutation site, and a mutation from K (Lys) to N (Asn) in codon 317 was identified in the SCN5A gene, indicating the successful induction of the mutation at K317N of the SCN5A gene. CONCLUSION: PCR site-directed mutagenesis is accurate and highly efficient, and the successfully constructed recombinant expression plasmid pRc/CMV-hH1 (K317N) may provide a molecular basis for further functional and genomic investigation of SCN5A.


Asunto(s)
Mutación , Reacción en Cadena de la Polimerasa/métodos , Canales de Sodio/genética , Taquicardia Ventricular/genética , Fibrilación Ventricular/genética , Humanos , Mutagénesis Sitio-Dirigida , Canal de Sodio Activado por Voltaje NAV1.5 , Plásmidos , Recombinación Genética , Síndrome
20.
Clin Chim Acta ; 411(9-10): 719-24, 2010 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-20138860

RESUMEN

BACKGROUND: MMP-2 and TIMP-2 play important roles in the pathogenesis of arrhythmogenic atrial remodeling, and may contribute to the development and persistence of atrial fibrillation (AF). Functional polymorphisms in the promoter of MMP-2 and TIMP-2 gene may modulate an individual's susceptibility to AF. METHODS: A total of 881 hypertensive heart disease patients from Chinese Han population (128 with and 753 without AF) were recruited in this study. The genotypes of the MMP2-1306C>T and -735C>T polymorphisms and TIMP-2 -418G>C polymorphisms were determined using PCR based method. The plasma concentration of TIMP-2 was measured by enzyme-linked immunosorbent assay in a subgroup with 81 patients. RESULTS: Both genotype distribution and allele frequency of the TIMP-2 -418G>C polymorphism were significantly different between the AF and control group (P=0.005 and P=0.001, respectively). The C allele carriers (GC+CC) had a significantly increased risk of AF compared with the GG homozygotes (odds ratio,1.77, 95% CI 1.21-2.92, P=0.009) in a logistic regression model after adjustment for age, left atrial dimension, left ventricular mass index, and antihypertensive drugs. The C allele carriers also had reduced levels of plasma TIMP-2 levels compared with GG homozygotes in both AF patients and control subjects. No relationship was found in this cohort between the presence of the MMP-2 -1306C>T and -735C>T polymorphism and AF. CONCLUSIONS: The TIMP-2 -418G>C polymorphism is significantly associated with an increased susceptibility to AF in Chinese Han patients with hypertensive heart disease. The -418C allele, which is associated with a decreased expression of TIMP-2, might be a genetic risk for the development of AF in this cohort.


Asunto(s)
Fibrilación Atrial/genética , Hipertensión/complicaciones , Metaloproteinasa 2 de la Matriz/genética , Polimorfismo de Nucleótido Simple/genética , Inhibidor Tisular de Metaloproteinasa-2/genética , Anciano , Anciano de 80 o más Años , Fibrilación Atrial/sangre , Fibrilación Atrial/complicaciones , China , Femenino , Frecuencia de los Genes/genética , Genotipo , Atrios Cardíacos/patología , Humanos , Hipertensión/sangre , Hipertensión/genética , Hipertrofia Ventricular Izquierda/complicaciones , Hipertrofia Ventricular Izquierda/patología , Masculino , Persona de Mediana Edad , Factores de Riesgo , Inhibidor Tisular de Metaloproteinasa-2/sangre
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