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1.
Quant Imaging Med Surg ; 13(1): 27-36, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36620153

RESUMO

Background: This study aimed to explore the association between deep medullary veins (DMVs) and the neuroimaging burden of cerebral small vessel disease (CSVD). Methods: In this cross-sectional study based on a retrospective analysis, a total of 248 patients (183 males and 65 females; mean age ± standard deviation, 69.5±14.8 years) diagnosed with CSVD with complete imaging and clinical data were enrolled. Neuroimaging markers of CSVD, including white matter hyperintensities, lacunes, prominent perivascular spaces (PVSs), and cerebral microbleeds (CMBs), were identified, and the total burden of CSVD was scored. Both DMV number and DMV score were used for assessment using susceptibility-weighted imaging (SWI). Results: With the exception of perivascular spaces, more severe neuroimaging markers were observed in patients with a higher DMV score. After adjustments were made for age and body mass index (BMI), a higher DMV score (ß=1.39; P<0.001) and smaller DMV number (ß=-2.55; P=0.001) were associated with an increased CSVD burden. The degree of CMBs was independently correlated with both DMV score (ß=1.60; P<0.001) and DMV number (ß=-2.27; P=0.009). The association between lacunes and DMV score was also significant (ß=0.97; P=0.026). Conclusions: Both DMV score and DMV number are potential imaging indicators of CSVD.

2.
J Clin Med ; 11(13)2022 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-35806913

RESUMO

The differential diagnosis of a cerebral dissecting aneurysm (DA) and a hemorrhagic saccular aneurysm (SA) often depends on the intraoperative findings; thus, improved non-invasive imaging diagnosis before surgery is essential to distinguish between these two aneurysms, in order to provide the correct formulation of surgical procedure. We aimed to build a radiomic model based on high-resolution vessel wall magnetic resonance imaging (VW-MRI) and a machine-learning algorithm. In total, 851 radiomic features from 146 cases were analyzed retrospectively, and the ElasticNet algorithm was used to establish the radiomic model in a training set of 77 cases. A clinico-radiological model using clinical features and MRI features was also built. Then an integrated model was built by combining the radiomic model and clinico-radiological model. The area under the ROC curve (AUC) was used to quantify the performance of models. The models were evaluated using leave-one-out cross-validation in a training set, and further validated in an external test set of 69 cases. The diagnostic performance of experienced radiologists was also assessed for comparison. Eight features were used to establish the radiomic model, and the radiomic model performs better (AUC = 0.831) than the clinico-radiological model (AUC = 0.717), integrated model (AUC = 0.813), and even experienced radiologists (AUC = 0.801). Therefore, a radiomic model based on VW-MRI can reliably be used to distinguish DA and hemorrhagic SA, and, thus, be widely applied in clinical practice.

3.
Artigo em Inglês | MEDLINE | ID: mdl-36612977

RESUMO

Sarcopenia is associated with increased morbidity and mortality in Crohn's disease. The present study is aimed at investigating the different diagnostic performance of different machine learning models in identifying sarcopenia in Crohn's disease. Patients diagnosed with Crohn's disease at our center provided clinical, anthropometric, and radiological data. The cross-sectional CT slice at L3 was used for segmentation and the calculation of body composition. The prevalence of sarcopenia was calculated, and the clinical parameters were compared. A total of 167 patients were included in the present study, of which 127 (76.0%) were male and 40 (24.0%) were female, with an average age of 36.1 ± 14.3 years old. Based on the previously defined cut-off value of sarcopenia, 118 (70.7%) patients had sarcopenia. Seven machine learning models were trained with the randomly allocated training cohort (80%) then evaluated on the validation cohort (20%). A comprehensive comparison showed that LightGBM was the most ideal diagnostic model, with an AUC of 0.933, AUCPR of 0.970, sensitivity of 72.7%, and specificity of 87.0%. The LightGBM model may facilitate a population management strategy with early identification of sarcopenia in Crohn's disease, while providing guidance for nutritional support and an alternative surveillance modality for long-term patient follow-up.


Assuntos
Doença de Crohn , Sarcopenia , Humanos , Masculino , Feminino , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Doença de Crohn/complicações , Doença de Crohn/diagnóstico , Doença de Crohn/epidemiologia , Sarcopenia/diagnóstico , Sarcopenia/epidemiologia , Sarcopenia/etiologia , Medição de Risco
4.
Quant Imaging Med Surg ; 11(11): 4627-4643, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34737929

RESUMO

The third-generation dual-source computed tomography (DSCT) is among the most advanced imaging methods. It employs noise-optimized virtual monoenergetic imaging (VMI+) technology. It uses the frequency-split method to extract high-contrast image information from low-energy images and low-noise information from images reconstructed at an optimal energy level, combining them to obtain the final image with improved quality. This review is the first to summarize the results of clinical studies that primarily and recently evaluated the VMI+ technique based on tumor, blood vessel, and other lesion classification. We aim to assist radiologists in quickly selecting the appropriate energy level when performing image reconstruction for superior image quality in clinical work and providing several ideas for future scientific research of the VMI+ technique. Presently, VMI+ reconstruction is mostly used for images of various tumors or blood vessels, including coronary plaques, coronary stents, deep vein thromboses, pulmonary embolisms (PEs), active arterial hemorrhages, and endoleaks after endovascular aneurysm repair. In addition, VMI+ has been used for imaging children's heads, liver lesions, pancreatic lacerations, and reducing metal artifacts. Regarding the reconstruction at the optimal energy level, the VMI+ technique yielded a higher image quality than the pre-optimized virtual monoenergetic imaging (VMI) technique and single-energy CT. Moreover, either low concentrations of contrast medium or low iodine injection rates can be applied before VMI+ reconstruction at a low-energy level to reduce contrast agent-related kidney injury risk. After reconstructing an image at the optimal energy level, both the image's window width and level can also be adjusted to improve the image effect's reach and diagnosis suitability. To improve image quality and lesion-imaging clarity and reduce the use of contrast agents, VMI+ reconstruction technology has been applied clinically, in which the selection of energy level is the key to the whole reconstruction process. Our review summarizes these optimal levels for radiologists' reference and suggests new ideas for the direction of future VMI+ research.

5.
J Cancer ; 12(5): 1493-1498, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33531994

RESUMO

Background: Most esophageal cancer patients are diagnosed at an advanced stage when there are few effective treatments. Transarterial infusion chemotherapy is a local chemotherapy method wherein chemotherapeutic drugs are directly injected into tumor vessels. Methods: Transarterial infusion chemotherapy was performed on advanced esophageal cancer patients once a month, and each patient underwent 1-3 treatments. The clinical results, complications, and effectiveness rates of each treatment episode were recorded and analyzed. Results: Transarterial infusion chemotherapy was successfully performed in all patients, and no severe complications such as paraplegia or death were noted. Complete response, partial response, and stable disease were noted in 17.3% (13/75), 77.3% (58/75), and 5.3% (4/75) of cases after transarterial infusion chemotherapy, respectively. The total treatment efficacy (complete response + partial response) was 94.7%. All cases exhibited improvement in clinical stage, with a marked decrease in dysphagia. Subsequent treatments were administered to 13 patients, including radical radiation in 7 and chemotherapy in 6. During follow-up, death was caused by progressive carcinoma in 20, tumor-related pneumatic infection and respiratory failure in 11, and gastrointestinal hemorrhage in 17. The median survival time was 15 months and the 1-year survival rate was 58.1%. Conclusions: Transarterial infusion chemotherapy may be safely and effectively used for treatment of advanced esophageal cancer.

6.
Langmuir ; 37(1): 524-541, 2021 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-33346664

RESUMO

In this article, a novel and facile method is used to construct superhydrophobic surfaces on aluminum alloys. A solution of aluminum chloride hexahydrate and N-dodecyltrimethoxysilane (DTMS) in ethanol was used as the electrolyte solution. The hydrolysis of DTMS was accelerated during the electrodeposition process, and the hydrolysate was bonded to a pretreated aluminum surface. The prepared aluminum alloy sample exhibits both superhydrophobicity (the surface water contact angle reached 155°) and excellent corrosion resistance. The inhibition efficiency of this sample is as high as 99.9% in 3.5 wt % NaCl solution, which remains at 98% even after 30 days of immersion. Thus, our fabrication can be well applied to the field of marine corrosion protection. Therefore, the working mechanism was discussed by confocal Raman microspectroscopy (CRM). In addition, the investigation by CRM and electrochemical impedance spectroscopy (EIS) also indicates that superhydrophobic samples show good stability in NaCl solution. The fabrication method can inspire new ideas for the construction of superhydrophobic aluminum alloys in the marine environment.

8.
J Vasc Interv Radiol ; 31(10): 1645-1653, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32951974

RESUMO

PURPOSE: To determine the efficacy and safety of the combination of bronchial arterial infusion (BAI) chemotherapy and transarterial chemoembolization with the use of drug-eluting embolic (DEE) particles in the treatment of unresectable advanced lung cancer. MATERIALS AND METHODS: A retrospective review was performed of 23 patients with unresectable lung cancer (stage III/IV) who received BAI chemotherapy and DEE chemoembolization. Treatment response was assessed by enhanced CT and evaluated on the basis of Response Evaluation Criteria In Solid Tumors at 30 d after the last combination treatment. Patients were followed up until death or March 15, 2020, whichever was first. Overall survival (OS) was estimated by Kaplan-Meier analysis, and factors associated with OS were evaluated by Cox proportional-hazards test. RESULTS: Complete response, partial response, stable disease, and progressive disease were seen in 2, 16, 5, and 0 patients at 30 d after the last combination treatment, respectively; therefore, the overall response rate was 78.3% and the disease control rate was 100%. Preprocedure symptoms (hemoptysis in 7 patients and dyspnea in 10) resolved in all cases after combination therapy. Nineteen patients died during follow-up, and 4 survived. Median OS was 15.6 mo (95% confidence interval, 10.1-21.1 mo). On univariate analysis and multivariate analysis, tumor/node/metastasis staging was an independent risk factor for prognosis. There were no serious adverse events during the procedures. CONCLUSIONS: The combination of BAI chemotherapy plus DEE chemoembolization appears to be a promising method for treatment of advanced lung cancer.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Artérias Brônquicas , Quimioembolização Terapêutica , Doxorrubicina/análogos & derivados , Irinotecano/administração & dosagem , Neoplasias Pulmonares/terapia , Inibidores da Topoisomerase I/administração & dosagem , Inibidores da Topoisomerase II/administração & dosagem , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Quimioembolização Terapêutica/efeitos adversos , Quimioembolização Terapêutica/mortalidade , Progressão da Doença , Doxorrubicina/administração & dosagem , Doxorrubicina/efeitos adversos , Feminino , Humanos , Infusões Intra-Arteriais , Irinotecano/efeitos adversos , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Inibidores da Topoisomerase I/efeitos adversos , Inibidores da Topoisomerase II/efeitos adversos , Resultado do Tratamento
9.
J Stroke Cerebrovasc Dis ; 29(12): 105268, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32992167

RESUMO

OBJECTIVE: To build radiomic model in differentiating dissecting aneurysm (DA) from complicated saccular aneurysm (SA) based on high-resolution magnetic resonance imaging (HR-MRI) through machine-learning algorithm. METHODS: Overall, 851 radiomic features from 77 cases were retrospectively analyzed, and the ElasticNet algorithm was used to build the radiomic model. A clinico-radiological model using clinical features and conventional MRI findings was also built. An integrated model was then built by incorporating the radiomic model and clinico-radiological model. The diagnostic abilities of these models were evaluated using leave one out cross validation and quantified using the receiver operating characteristic (ROC) analysis. The diagnostic performance of radiologists was also evaluated for comparison. RESULTS: Five features were used to form the radiomic model, which yielded an area under the ROC curve (AUC) of 0.912 (95 % CI 0.846-0.976), sensitivity of 0.852, and specificity of 0.861. The radiomic model achieved a better diagnostic performance than the clinico-radiological model (AUC=0.743, 95 % CI 0.623-0.862), integrated model (AUC=0.888, 95 % CI 0.811-0.965), and even many radiologists. CONCLUSION: Radiomic features derived from HR-MRI can reliably be used to build a radiomic model for effectively differentiating between DA and complicated SA, and it can provide an objective basis for the selection of clinical treatment plan.


Assuntos
Dissecção Aórtica/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador , Aneurisma Intracraniano/diagnóstico por imagem , Aprendizado de Máquina , Imageamento por Ressonância Magnética , Adulto , Idoso , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Estudos Retrospectivos
10.
ACS Omega ; 5(27): 16976-16985, 2020 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-32685868

RESUMO

Bipolar plates, accounting for a large proportion of proton exchange membrane fuel cells (PEMFCs), are highly susceptible to corrosion by H+, SO4 2-, and so on because of the strong acid-rich and oxygen/hydrogen-rich environments. In this work, the corrosion resistance of aluminum alloy bipolar plates modified in the cathodic environment of PEMFCs has been investigated. A honeycomb structure is constructed by anodizing on an aluminum alloy (AA5052) bipolar plate, and a polyacrylonitrile (PAN) film is prepared by infusing PAN solution on the surface. From scanning electron microscopy and atomic force microscopy, we observe that the porous structure of the aluminum alloy surface is more advantageous for enhancing the mechanical engagement between PAN and the aluminum alloy. Therefore, the PAN film is dense and smooth. Electrochemical tests confirm that the PAN film greatly improves the corrosion resistance of the aluminum alloy bipolar plate under the cathodic environment of the PEMFC. When graphene oxide (GO) is added, the charge-transfer resistance (R ct) is not only improved but also the stability under oxygen-rich acidic conditions is prolonged.

12.
J Vasc Surg Venous Lymphat Disord ; 8(6): 945-952, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32418826

RESUMO

OBJECTIVE: Our study aimed to evaluate the safety and efficacy of sequential interventional therapy for Budd-Chiari syndrome (BCS) caused by obstruction of the inferior vena cava (IVC) with fresh thrombus in the IVC. METHODS: Full medical records were obtained for 20 patients with BCS associated with fresh IVC thrombus who received sequential interventional therapy from 2014 to 2019 at our hospital. All patients underwent small-diameter percutaneous transluminal angioplasty (PTA) balloon catheter predilation combined with sequential catheter-directed thrombolysis and large-diameter PTA balloon dilation. Ultrasound examinations were performed at 1 week, 1 month, 3 months, and every 6 months thereafter. Therapeutic effects and perioperative and postoperative adverse effects were recorded to assess the safety of the treatment. RESULTS: All 20 patients were treated with small PTA balloon catheters (diameter, 10-14 mm) to predilate the occlusive segment of the IVC. Urokinase 400,000 to 600,000 (465,000 ± 93,000) units was administered to patients through the catheter for 6 to 20 (9.7 ± 4.2) consecutive days postoperatively. Ultrasound re-examination showed that the IVC thrombus disappeared completely in 14 patients (70.0%), and a small amount of the old thrombus remained in 6 patients (30.0%). After thrombolysis, all 20 patients received PTA balloon dilation (diameter, 26-30 mm) in the stenosed IVC segment, and blood flow recovered subsequently. No pulmonary embolism or death occurred in the perioperative course. The perioperative survival rate was 100.0%. CONCLUSIONS: Sequential interventional therapy for BCS associated with fresh IVC thrombus is safe and effective.


Assuntos
Angioplastia com Balão , Síndrome de Budd-Chiari/terapia , Fibrinolíticos/administração & dosagem , Terapia Trombolítica , Ativador de Plasminogênio Tipo Uroquinase/administração & dosagem , Veia Cava Inferior , Adulto , Idoso , Angioplastia com Balão/efeitos adversos , Síndrome de Budd-Chiari/diagnóstico por imagem , Síndrome de Budd-Chiari/fisiopatologia , Terapia Combinada , Feminino , Fibrinolíticos/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Terapia Trombolítica/efeitos adversos , Fatores de Tempo , Resultado do Tratamento , Ativador de Plasminogênio Tipo Uroquinase/efeitos adversos , Veia Cava Inferior/diagnóstico por imagem , Veia Cava Inferior/fisiopatologia , Adulto Jovem
13.
Catal Today ; 358(1): 324-332, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33424117

RESUMO

A novel porous ceramic sheet supported nickel particles reactor was obtained by an in-situ preparation method. This reactor was then used to investigate continuous-flow catalysis of nitroaromatic compounds and methyl orange. The details of the structure and morphology were characterized by XRD, SEM, XPS, Raman, element mapping, mercury intrusion method and Archimedes principle. The porous ceramic sheet supported Ni particles reactor exhibited excellent catalytic performance in the catalytic reduction of p-nitrophenol and methyl orange by sodium borohydride at room temperature. Both the conversion of p-nitrophenol (5 mM) and methyl orange (0.3 mM) reached nearly 100% at the injection speed of 2.67 mL·min-1. In addition, it maintained conversions of 100% after 10 recycling time since the porous ceramic sheet could reduce the aggregation for Ni particles. Furthermore, the chemisorbed oxygen, and the strong interaction between Ni and porous ceramic sheet resulted in a highly efficient, recoverable, and cost-effective multifunctional reactor. All of these advantages present new opportunities to be implemented in the field of waste water treatment and environmental toxicology. Ultimately, the porous ceramic sheet could also support other metal nanomaterial, and used in other fields of environmental catalysis.

14.
J Hazard Mater ; 381: 120934, 2020 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-31374373

RESUMO

The harmless disposal of abandoned and toxic V2O5(WO3)/TiO2 (VWT) deNOx catalysts has become a worldwide great demand, a new resource path for hydrogen production from steam reforming of formaldehyde and water using the waste VWT deNOx catalysts as catalyst carriers was proposed. The waste V2O5-based catalysts supported NiO (N/VWT) catalysts prepared by impregnation method were comparatively studied for hydrogen production. The H2 and CO selectivity of the optimum N/VWT separately reached 100% and 72.5%, and the formaldehyde conversion of the N/VWT reached 86.3% at 400 ℃ and higher than 93.0% at 450-600 ℃. Analysis showed that the hydroxyl species played the most important role, and its richness determined the catalytic performance directly. The high acid sites and excellent redox properties were beneficial to enhance the catalytic performance. The in situ DRIFT study verified that the hydrogen bonds between formate species and hydroxyl groups reduced reaction steps, which accelerated the progress of the reaction. The adsorbed formaldehyde transformed to formate species firstly, and then produced H2 and CO2 (or CO) by dehydrogenation. Ultimately, the resource utilization path not only completely solved the harmless problems of the waste V2O5-based deNOx catalysts and formaldehyde, but also contributed to the hydrogen production.

15.
J Pediatr Surg ; 55(3): 437-440, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31376916

RESUMO

PURPOSE: Pharyngeal or esophageal perforation with mediastinal abscess is notably dangerous in children and can be very difficult to treat. We aimed to determine the safety and efficacy of the transnasal placement of a mediastinal drainage catheter and a nasojejunal feeding tube, with or without gastric decompression, in the treatment of the above perforations in children. METHODS: We placed transnasal mediastinal drainage catheters and nasojejunal feeding tubes in 14 pediatric patients. Patients with esophageal perforation also underwent the placement of a gastric decompression tube. Four of these patients additionally received chest drainage tubes. RESULTS: The fistula healed after a median of 66 days (range, 5-404 days). Corrosive esophagitis occurred in two patients with pharyngeal perforations. One of these patients underwent surgical treatment 2 months after fistula healing, and the other underwent repeated balloon dilatation procedures for cicatricial restenosis. Four months after the fistula had healed, the patients with esophageal perforations were all free from recurrence. CONCLUSION: The use of interventional radiology to place a transnasal mediastinal drainage catheter, a nasojejunal feeding tube, and a gastric decompression tube is a safe, easy, inexpensive, and efficacious way to treat pharyngeal or esophageal perforation complicated by mediastinal abscess in children. TYPE OF STUDY: Treatment study. LEVEL OF EVIDENCE: Level IV.


Assuntos
Perfuração Esofágica , Doenças do Mediastino/complicações , Doenças Faríngeas , Radiografia Intervencionista , Abscesso , Criança , Drenagem/efeitos adversos , Drenagem/instrumentação , Drenagem/métodos , Nutrição Enteral/efeitos adversos , Nutrição Enteral/instrumentação , Nutrição Enteral/métodos , Perfuração Esofágica/diagnóstico por imagem , Perfuração Esofágica/etiologia , Perfuração Esofágica/cirurgia , Humanos , Doenças Faríngeas/diagnóstico por imagem , Doenças Faríngeas/etiologia , Doenças Faríngeas/cirurgia , Radiografia Intervencionista/efeitos adversos , Radiografia Intervencionista/métodos
17.
Eur Spine J ; 28(8): 1783-1792, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31041597

RESUMO

PURPOSE: The purpose of this study was to evaluate the effects of noise-optimised virtual monoenergetic imaging (VMI+) reconstructions on reducing metal artefacts compared to traditional virtual monoenergetic imaging (VMI) and linearly blended (M_0.6) reconstructions in patients with lumbar metal internal fixation in dual-energy CT (DECT). METHODS: Forty patients who underwent DECT were evaluated in this retrospective study. Images were reconstructed with M_0.6 and with VMI+ and VMI at 10-keV intervals from 40 keV to 190 keV. Attenuation and noise were measured in the hyperdense artefacts, hypodense artefacts, spinal canal, abdominal aorta (AA), and inferior vena cava (IVC). An artefact index (AI) was calculated. A subjective evaluation of the metal-bone interface, surrounding soft tissue, spinal canal, AA, and IVC was conducted. RESULTS: The AI values for the hypodense artefacts, spinal canal, and IVC were lowest in the 130 keV VMI+ series, for the hyperdense artefacts in the 120 keV VMI+ series, and for the AA in the 190 keV VMI+ series. Except for the hypodense artefacts, the AI values were lower compared to the M_0.6 images and all the VMI series (all p < 0.05). The subjective image quality was highest at 130 keV VMI+ for the metal-bone interface, surrounding soft tissue, AA, and IVC, and at 120 keV VMI+ for the spinal canal. Except for the AA, these rating scores were higher compared to the M_0.6 images and the entire VMI series (all p < 0.05). CONCLUSIONS: DECT with high-keV VMI+ efficiently reduces metal artefacts and shows superior image quality in patients with lumbar internal fixation. These slides can be retrieved from Electronic Supplementary Material.


Assuntos
Artefatos , Vértebras Lombares , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodos , Tomografia Computadorizada por Raios X/métodos , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Estudos Retrospectivos , Fusão Vertebral/instrumentação
18.
Small ; 14(34): e1800927, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30028571

RESUMO

The hydrogen economy is accelerating technological evolutions toward highly efficient hydrogen production. In this work, the catalytic performance of NiO/NaCl for hydrogen production via autothermal reforming of ethyl acetate and water is further improved through lanthanum modification, and the resulted 3%-NiLaOy /NaCl catalyst achieves as high as 93% H2 selectivity and long-term stability at 600 °C. The promoting effect is caused by the strong interactions between lanthanum and NiO/NaCl, by which LaNiO3 and a novel LaOCl phase are formed. The key role of LaOCl in promoting low-temperature hydrogen production is highlighted, while effects of LaNiO3 are well known. The LaOCl (010) facet possesses high adsorption capacity toward co-chemisorbing ethyl acetate and water. LaOCl strongly interacts with ethyl acetate and H2 O in the form of hydrogen bonding and coordination effect. The interactions induce tensions inside ethyl acetate and H2 O, activate the molecules, and hence decrease the energy barrier for reaction. In situ Fourier transform infrared spectroscopy (FTIR) reveals that LaOCl along with NaCl enhances the adsorption ability of NiO/NaCl. Moreover, LaOCl improves the dispersion of Ni species in NiO-LaNiO3 -LaOCl nanosheets, which possess abundant active sites. The effects together promote hydrogen evolution. Furthermore, the NiLaOy /NaCl catalyst can be easily reborn after deactivation due to the water solubility of NaCl.

19.
ACS Appl Mater Interfaces ; 8(12): 7977-90, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26930503

RESUMO

Porous Fe3O4/C composite nanofoils, characterized by a thickness of ∼20 nm and with ∼8 nm open pores and ∼5 nm Fe3O4 nanoparticles embedded in the carbon matrix, were prepared for the first time using Na-citrate to mediate the growth of hexagonal Fe-ethylene glycolate nanosheets and subsequently annealing them at 350 °C in N2. It has been found that the Fe-ethylene glycolate nanosheets can be effectively slimmed by increasing the concentration of Na-citrate, and the microstructures of Fe3O4/C nanocomposites may be tailored by the annealing temperature. When tested as the anode materials in LIBs, the Fe3O4/C nanofoils obtained after annealing at 350 °C were found to exhibit superior electrochemical performance due to its optimal microstructure, featured by a reversible capacity of 1314.4 mAh g(-1) at 0.4 A g(-1) over 100 cycles, 1034.2 mAh g(-1) at 1 A g(-1), and 686.4 mAh g(-1) at 5 A g(-1) after 500 cycles, whereas the annealing treatments at 450 and 550 °C render the Fe3O4/C nanocomposites with the inferior electrochemical performances as a result of shrinking porous microstructures and coarsening of Fe3O4 nanoparticles in the carbon matrix. With a particle-size control model proposed herein, the cycle discharging behaviors of the Fe3O4/C nanocomposites with different microstructures are well explained from the perspective of the local confinement of Fe3O4 nanoparticles inside the carbon matrix and their evolution in size and composite microstructure during the charge/discharge cycling.

20.
ACS Appl Mater Interfaces ; 5(24): 12876-86, 2013 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-24251947

RESUMO

With the analytical grade Ce(NO3)3·6H2O, Sm(NO3)3·6H2O, and Na2CO3 as starting materials, Sm0.2Ce0.8O1.9(SDC)/Na2CO3 nanocomposite electrolytes were prepared through a rare-earth/sodium carbonate complex precipitation, prefiring, and sintering operations. The phase components and microstructures were studied and characterized by XRD, FESEM, TEM, and TG-DSC. In particular, the interfacial interactions between the phases of SDC crystallites and amorphous Na2CO3 were deliberately probed by Raman and infrared spectroscopies. It has been found that the amorphous carbonates in the SDC/Na2CO3 composites are tightly bound to the surface of SDC nanocrystals to form an intimate shell-layer via a long-range interface interaction, characterized by ∼8 nm in thickness and a red-shift of 15 cm(-1) for the Raman symmetrical vibration mode of carbonate ions with reference to the crystalline Na2CO3, which is practically enabled to frustrate the crystallization of Na2CO3 and enhance the transport properties of oxide ions in the SDC/Na2CO3 composite electrolytes because of the disordered interface microstructures. Moreover, smaller SDC nanocrystals were found to achieve higher conductivity enhancements for the SDC/Na2CO3 composite electrolytes and the {100} facets on the surface of SDC nanocrystals are believed to be more important than the other facets because of their strong electropositivity. This effect makes the SDC/Na2CO3 composite sample prefired at 600 °C realize a much higher ionic conductivity than the samples prefired at the other temperatures.

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