Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 60
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Small ; 20(12): e2306563, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37929642

RESUMEN

Crystalline carbon nitride (CCN), derived from amorphous polymeric CN, is considered as a new generation of metal-free photocatalyst because of its high crystallinity. In order to further promote the photocatalytic performance of CCN, p-type MnO nanoparticles are in situ synthesized and merged with n-type CCN through a one-pot process to form p-n heterojunction. The formed interfacial electric field between the semiconductors with different work functions efficiently breaks the coulomb interaction between MnO and CCN. The prepared catalysts exhibit drastically increased photocatalytic hydrogen evolution (PHE) activity integrated with oxidation of alkyl and aryl alcohols under irradiation of visible light. In the aqueous solution of benzyl alcohol (BzOH), the hydrogen generation rate over MnO/CCN (39.58 µmol h-1) is nearly 7 times and 37 times that of pure CCN (5.76 µmol h-1) and CN (1.06 µmol h-1), respectively, combining with oxidation of BzOH to benzaldehyde. This work proposes an avenue for in situ construction of a novel 2D material-based S-scheme heterojunction and extends its application in solar energy conservation and utilization.

2.
J Med Internet Res ; 22(5): e19087, 2020 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-32401210

RESUMEN

BACKGROUND: In December 2019, pneumonia cases of unknown origin were reported in Wuhan City, Hubei Province, China. Identified as the coronavirus disease (COVID-19), the number of cases grew rapidly by human-to-human transmission in Wuhan. Social media, especially Sina Weibo (a major Chinese microblogging social media site), has become an important platform for the public to obtain information and seek help. OBJECTIVE: This study aims to analyze the characteristics of suspected or laboratory-confirmed COVID-19 patients who asked for help on Sina Weibo. METHODS: We conducted data mining on Sina Weibo and extracted the data of 485 patients who presented with clinical symptoms and imaging descriptions of suspected or laboratory-confirmed cases of COVID-19. In total, 9878 posts seeking help on Sina Weibo from February 3 to 20, 2020 were analyzed. We used a descriptive research methodology to describe the distribution and other epidemiological characteristics of patients with suspected or laboratory-confirmed SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection. The distance between patients' home and the nearest designated hospital was calculated using the geographic information system ArcGIS. RESULTS: All patients included in this study who sought help on Sina Weibo lived in Wuhan, with a median age of 63.0 years (IQR 55.0-71.0). Fever (408/485, 84.12%) was the most common symptom. Ground-glass opacity (237/314, 75.48%) was the most common pattern on chest computed tomography; 39.67% (167/421) of families had suspected and/or laboratory-confirmed family members; 36.58% (154/421) of families had 1 or 2 suspected and/or laboratory-confirmed members; and 70.52% (232/329) of patients needed to rely on their relatives for help. The median time from illness onset to real-time reverse transcription-polymerase chain reaction (RT-PCR) testing was 8 days (IQR 5.0-10.0), and the median time from illness onset to online help was 10 days (IQR 6.0-12.0). Of 481 patients, 32.22% (n=155) lived more than 3 kilometers away from the nearest designated hospital. CONCLUSIONS: Our findings show that patients seeking help on Sina Weibo lived in Wuhan and most were elderly. Most patients had fever symptoms, and ground-glass opacities were noted in chest computed tomography. The onset of the disease was characterized by family clustering and most families lived far from the designated hospital. Therefore, we recommend the following: (1) the most stringent centralized medical observation measures should be taken to avoid transmission in family clusters; and (2) social media can help these patients get early attention during Wuhan's lockdown. These findings can help the government and the health department identify high-risk patients and accelerate emergency responses following public demands for help.


Asunto(s)
Betacoronavirus , Infecciones por Coronavirus/epidemiología , Minería de Datos , Neumonía Viral/epidemiología , Medios de Comunicación Sociales , Adolescente , Adulto , Factores de Edad , Anciano , COVID-19 , Niño , Preescolar , China/epidemiología , Infecciones por Coronavirus/complicaciones , Femenino , Fiebre/etiología , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Pandemias , Neumonía Viral/complicaciones , SARS-CoV-2 , Adulto Joven
3.
Small ; 14(12): e1703599, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29430823

RESUMEN

Conjugated polymers with tailored donor-acceptor units have recently attracted considerable attention in organic photovoltaic devices due to the controlled optical bandgap and retained favorable separation of charge carriers. Inspired by these advantages, an effective strategy is presented to solve the main obstructions of graphitic carbon nitride (g-C3 N4 ) photocatalyst for solar energy conversion, that is, inefficient visible light response and insufficient separation of photogenerated electrons and holes. Donor-π-acceptor-π-donor polymers are prepared by incorporating 4,4'-(benzoc 1,2,5 thiadiazole-4,7-diyl) dianiline (BD) into the g-C3 N4 framework (UCN-BD). Benefiting from the visible light band tail caused by the extended π conjugation, UCN-BD possesses expanded visible light absorption range. More importantly, the BD monomer also acts as an electron acceptor, which endows UCN-BD with a high degree of intramolecular charge transfer. With this unique molecular structure, the optimized UCN-BD sample exhibits a superior performance for photocatalytic hydrogen evolution upon visible light illumination (3428 µmol h-1 g-1 ), which is nearly six times of that of the pristine g-C3 N4 . In addition, the photocatalytic property remains stable for six cycles in 3 d. This work provides an insight into the synthesis of g-C3 N4 -based D-π-A-π-D systems with highly visible light response and long lifetime of intramolecular charge carriers for solar fuel production.

4.
Phys Chem Chem Phys ; 17(22): 14827-35, 2015 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-25978305

RESUMEN

Advanced materials for electrocatalytic and photoelectrochemical water splitting are key for taking advantage of renewable energy. In this study, ZnO/ZnSe/CdSe/Cu(x)S core-shell nanowire arrays with a nanoporous surface were fabricated via ion exchange and successive ionic layer adsorption and reaction (SILAR) processes. The ZnO/ZnSe/CdSe/Cu(x)S sample displays a high photocurrent density of 12.0 mA cm(-2) under AM 1.5G illumination, achieves the highest IPCE value of 89.5% at 500 nm at a bias potential of 0.2 V versus Ag/AgCl, and exhibits greatly improved photostability. The functions of the ZnSe, CdSe, and Cu(x)S layers in the ZnO/ZnSe/CdSe/Cu(x)S heterostructure were clarified. ZnSe is used as a passivation layer to reduce the trapping and recombination of charge carriers at the interfaces of the semiconductors. CdSe functions as a highly efficient visible light absorber and builds heterojunctions with the other components to improve the separation and transportation of the photoinduced electrons and holes. Cu(x)S serves as a passivation layer and an effective p-type hole mediator, which passivates the defects and surface states of the semiconductors and forms p-n junctions with CdSe to promote the hole transportation at the semiconductor-electrolyte interface. The nanoporous surface of the ZnO/ZnSe/CdSe/Cu(x)S core-shell nanowire arrays, together with the tunnel transportation of the charge carriers in the thin films of ZnSe and CdSe, also facilitates the kinetics of photoelectrochemical reactions and improves the optical absorption as well.

5.
Hepatology ; 57(3): 1024-34, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23079960

RESUMEN

UNLABELLED: Osteopontin (OPN) plays a crucial role in hepatocellular carcinoma (HCC) metastasis. However, little is known about the impact of OPN polymorphisms on cancer progression. In this study, we first identified the single nucleotide polymorphisms (SNPs) in the OPN promoter region by direct sequencing in 30 HCCs, and then evaluated the prognostic values of the selected ones in two large cohorts of 826 HCC patients. The identified SNPs were functionally analyzed using in vitro and in vivo assays and their correlations with OPN levels were also evaluated. Only SNP at locus -443 and their related haplotypes (Ht2: -1748A/-616G/-443T/-155* [*indicates base deletion]; Ht3: -1748A/-616G/-443C/-155*) were significantly associated with overall survival (OS) and time to recurrence (TTR). The patients with the -443TT/TC genotype or Ht2 had a shorter OS and TTR compared with those with -443CC genotype or Ht3. This was further confirmed in the validation cohort. Moreover, this correlation remained significant in patients with small HCCs (≤5 cm). Multivariate analyses indicated that the prognostic performance of the -443 genotypes (OS, P=0.031; TTR, P=0.005) and their related haplotypes (OS, P=0.002; TTR, P=0.001) was independent of other clinicopathological factors. The Ht2 and -443TT genotype could significantly increase the promoter transcriptional activity and expression level of OPN compared with the Ht3 or -443CC genotype, and lead to an obvious increase in both in vitro invasion and in vivo tumor growth and lung metastasis of HCC cells (P<0.05). CONCLUSION: The genetic variation at locus -443 of the OPN promoter plays important roles in the regulation of OPN expression and cancer progression of HCCs, which is a novel determinant and target for HCC metastasis and prognosis.


Asunto(s)
Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/secundario , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patología , Osteopontina/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Pruebas Genéticas , Haplotipos , Humanos , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple/genética , Pronóstico , Regiones Promotoras Genéticas/genética
6.
J Biomed Inform ; 48: 130-6, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24486562

RESUMEN

Extracting information from unstructured clinical narratives is valuable for many clinical applications. Although natural Language Processing (NLP) methods have been profoundly studied in electronic medical records (EMR), few studies have explored NLP in extracting information from Chinese clinical narratives. In this study, we report the development and evaluation of extracting tumor-related information from operation notes of hepatic carcinomas which were written in Chinese. Using 86 operation notes manually annotated by physicians as the training set, we explored both rule-based and supervised machine-learning approaches. Evaluating on unseen 29 operation notes, our best approach yielded 69.6% in precision, 58.3% in recall and 63.5% F-score.


Asunto(s)
Inteligencia Artificial , Carcinoma/diagnóstico , Neoplasias Hepáticas/diagnóstico , Procesamiento de Lenguaje Natural , Algoritmos , Carcinoma/patología , China , Simulación por Computador , Sistemas de Computación , Minería de Datos/métodos , Registros Electrónicos de Salud , Humanos , Lenguaje , Neoplasias Hepáticas/patología , Informática Médica/métodos , Programas Informáticos
7.
J Nanosci Nanotechnol ; 14(9): 6800-8, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25924334

RESUMEN

Hierarchical Bi2O2CO3/Bi2MoO6 heterostructured photocatalysts composed of nanoplatelets of Bi2O2CO3 and Bi2MoO6 were successfully prepared by a facile template-free solvothermal process. The microsphere-like Bi2O2CO3/Bi2MoO6 composites exhibited superior visible light photocatalytic activity towards degradation of rhodamine B. The highest degradation efficiency was observed on the material with the Bi/Mo molar ratio of 2.88/1, which can degrade 99% rhodamine B within 90 min, while only 44% rhodamine B was degraded over the pure Bi2MoO6 microspheres and 2% over the Bi2O2CO3 nanoplatelets. The dramatic enhancement in their photocatalytic performance of the Bi2O2CO3/Bi2MoO6 photocatalysts can be attributed to the high surface area and the effective separation of the photoinduced carriers at the interfaces and in the semiconductors. The photo-generated h+(VB) in the Bi2O2CO3/Bi2MoO6 photocatalysts turn out to be the dominant active species in the photocatalytic reaction. Importantly, Bi2O2CO3/Bi2MoO6 displayed visible-light photocatalytic activity for the destruction of E. coli (the percent kill is 99.09 in 60 min). In addition, the Bi2O2CO3/Bi2MoO6 composite was very stable during the reaction and can be used repeatedly. These features mean the present heterostructured photocatalyst can be applied in environmental remediation, and waste water disinfection.


Asunto(s)
Bismuto/química , Microesferas , Molibdeno/química , Carbonatos , Nanoestructuras/química , Fotólisis
8.
Hematol Oncol ; 31(1): 29-33, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22488650

RESUMEN

There are two different international standards for the treatment of follicular lymphoma (FL): intensified therapy followed by autologous stem-cell transplantation (ASCT) and conventional therapy in the first-line setting. However, their role remains unclear. Our aim was to define the treatment effect of intensified therapy followed by ASCT compared with conventional therapy as first-line treatment of patients with FL in terms of overall survival (OS) and event-free survival (EFS). We searched for randomised controlled trials in Medline, Embase, the Cochrane controlled trials register and the Science Citation Index (1985 to June 2011). Effect measures used were hazard ratios (HR) for OS, EFS and secondary tumour rate. Two independent review authors extracted data and assessed quality of trials. Four trials were identified, covering a total of 941 subjects. The random-effects summary HR by comparing the treatment effect on OS between intensified and conventional therapy was 0.95 [0.70, 1.30] (p = 0.75), indicating that no additional survival benefit was derived from the intensified therapy followed by ASCT. A significant benefit of intensified therapy followed by ASCT as first-line treatment was detected in terms of EFS: the random-effects summary HR (intensified versus conventional therapy) was 0.59 [0.44, 0.79] (p < 0.001). This meta-analysis showed that despite its superior EFS, intensified therapy followed by ASCT does not improve the OS compared with conventional therapy.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Trasplante de Células Madre Hematopoyéticas , Linfoma Folicular/tratamiento farmacológico , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Carmustina/administración & dosificación , Cisplatino/administración & dosificación , Ensayos Clínicos como Asunto/estadística & datos numéricos , Terapia Combinada , Ciclofosfamida/administración & dosificación , Citarabina/administración & dosificación , Dexametasona/administración & dosificación , Supervivencia sin Enfermedad , Doxorrubicina/administración & dosificación , Etopósido/administración & dosificación , Femenino , Humanos , Interferón alfa-2 , Interferón-alfa/administración & dosificación , Linfoma Folicular/radioterapia , Linfoma Folicular/cirugía , Masculino , Melfalán/administración & dosificación , Persona de Mediana Edad , Neoplasias Primarias Secundarias/inducido químicamente , Neoplasias Primarias Secundarias/epidemiología , Prednisona/administración & dosificación , Proteínas Recombinantes/administración & dosificación , Inducción de Remisión , Análisis de Supervivencia , Tenipósido/administración & dosificación , Trasplante Autólogo , Resultado del Tratamiento , Vincristina/administración & dosificación , Irradiación Corporal Total
9.
J Nanosci Nanotechnol ; 13(8): 5868-73, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23882851

RESUMEN

Ni(1-x)Fe(x)O (x = 0-0.05) nanoplatelets were synthesized by a facile hydrothermal process. The crystal structure and morphology of the samples were characterized by X-ray diffraction and field emission scanning electron microscopy. The incorporation and the valence state of Fe in NiO nanoplatelets were determined by X-ray photoelectron spectroscopy. Doping NiO nanoplatelets by Fe greatly improves their sensing performance. The Ni0.97Fe0.03O sensor showed the highest response up to 59.5 to 100 ppm ethanol at 280 degrees C, which is a 28.2-fold increase compared to the pure NiO nanoplatelets. The incorporation of Fe3+ into the lattice of NiO results in the decrease of the effective hole concentrations, which plays a key role for the enhancement of the sensing properties. Fe-dopant can be a promising substitute for the noble metal additives to fabricate gas sensors with much lower cost. Finally, the gas sensing mechanism was discussed.

10.
J Nanosci Nanotechnol ; 13(1): 409-16, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23646747

RESUMEN

In this work, a novel environmental-friendly waterborne polyurethane/ZnAl-layered double hydroxides/ZnO nanoparticles composite (WPU/ZnAl-LDHs/ZnO) was synthesized via in-situ polymerization. ZnAl-LDHs and ZnAl-LDHs/ZnO were synthesized by refluxing in an oil bath. In order to disperse ZnAl-LDHs/ZnO homogeneously into WPU matrix, ZnAl-LDHs/ZnO was firstly functionalized by isophorone diisocyanate. The incorporated content of ZnAl-LDHs/ZnO in the composite has profound effect on such physical properties as mechanical strength, thermal stability and water swelling. It is demonstrated that appropriate amount of ZnAl-LDHs/ZnO with good dispersion in the WPU matrix significantly improves the physical performance of the composites. Finally, the antibacterial activity of the composite was tested against G(-) Escherichia coli and G(+) Staphylococcus aureus. The results indicate that WPU incorporated with ZnAl-LDHs/ZnO shows strong antibacterial activity upon contact.


Asunto(s)
Hidróxido de Aluminio/administración & dosificación , Fenómenos Fisiológicos Bacterianos/efectos de los fármacos , Nanopartículas/administración & dosificación , Nanopartículas/química , Poliuretanos/química , Óxido de Zinc/administración & dosificación , Hidróxido de Aluminio/química , Antibacterianos/química , Antibacterianos/efectos de la radiación , Supervivencia Celular/efectos de los fármacos , Ensayo de Materiales , Agua/química , Óxido de Zinc/química
11.
J Colloid Interface Sci ; 648: 898-906, 2023 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-37329601

RESUMEN

Photocatalytic performance of polymeric carbon nitride (CN) is primarily restricted by limited light utilization and poor charge separation efficiency. To this end, skeleton modification strategy was adopted by attaching thiophene ring and polar nickel complex (NiL) onto CN. The obtained bifunctionalized carbon nitride (TCN-NiL) displayed obviously elevated optical absorption and photoexcited charge separation efficiency. The NiL, with polar structure, plays as active sites like cocatalyst thus exhibited platinum-like H2 evolution activity from water splitting under visible light. The optimized photocatalytic H2 generation rate over TCN-NiL reached 136.7 µmol·h-1 without any cocatalyst, the highest rate reported so far in noble-metal-free CN-based catalysts, which is 5 times of that of CN loaded with 3 wt% Pt. Additionally, the maximum wavelength of performing H2 production capacity over TCN-NiL extends to 550 nm from 450 nm of CN, suggesting an excellent visible light absorption ability. This work provides a way for modifying CN to enhance the photocatalytic activities in a noble metal free system.

12.
J Nanosci Nanotechnol ; 12(8): 6294-300, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22962739

RESUMEN

In this study, Bi2MoO6 hollow microspheres were modified by depositing TiO2 nanoparticles through a simple hydrothermal method. The prepared TiO2/Bi2MoO6 photocatalysts were characterized by scanning and transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy. The photocatalytic performance of the heterostructured catalysts was evaluated by degradation of methylene blue (MB) under visible-light irradiation (lambda>420 nm). The photocatalysts based on nanostructured Bi2MoO6 and TiO2 exhibit much higher photocatalytic activity than the single-phase Bi2MoO6 or TiO2 and the mechanical mixture of Bi2MoO6 and TiO2 for degradation of MB under the same conditions. The results reported in this study provide insight into constructing other heterostructured photocatalysts.

13.
J Nanosci Nanotechnol ; 12(9): 6921-9, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23035415

RESUMEN

In this study, we report a facilely hydrothermal process for synthesizing SnO2 nanorods-graphene (SnO2 nanorods-GR) composite using graphite oxide and SnCl4 as raw materials. The SnO2 nanorods-GR composite was characterized by X-ray diffraction, electron microscopy, Xray photoelectron spectroscopy, and thermogravimetric analysis. Compared to commercial TiO2 nanoparticles P25 and neat SnO2 nanorods, the SnO2 nanorods-GR composite exhibits higher photocatalytic activity under UV light irradiation. The mechanism of its high photocatalytic activity is mainly ascribed to the synergy effect between SnO2 and graphene, in which graphene acts as an adsorbent and electron acceptor due to its large structure of pi-pi conjugation from sp2 hybrid carbon atoms. The results demonstrated in this study provide a promising way to enhance the photocatalytic activity by compounding semiconductive nanocrystals with graphene.

14.
J Colloid Interface Sci ; 616: 791-802, 2022 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-35248966

RESUMEN

The development of stable and efficient non-noble metal-based photocatalysts for water splitting is currently a key but challenging process for effective conversion and storage of sustainable energy. Here, we designed a new non-noble metal composite photocatalyst by covalently connecting nickel molecular ligand (NiL) to the graphitized carbon nitride (CN) framework for photocatalytic hydrogen evolution under visible light irradiation. Compared to CN, NiL-modified CN (NiL/CN) shows excellent photogenerated carrier migration rate. Without Pt as a co-catalyst, NiL/CN exhibits high photocatalytic activity (23.4 µmol h-1) with high stability. Experiments and theoretical calculations disclose that ligand-metal charge transfer (LMCT) mechanism plays a key role on the enhancement of photocatalytic activity. This work provides a promising method for future designing low-cost, high-performance photocatalysts for hydrogen production under solar light.

15.
Biomed J ; 45(3): 472-481, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35367669

RESUMEN

BACKGROUND: The impact of COVID-19 on public health has mandated an 'all hands on deck' scientific response. The current clinical study and basic research on COVID-19 are mainly based on existing publications or our knowledge of coronavirus. However, efficiently retrieval of accurate, relevant knowledge on COVID-19 can pose significant challenges for researchers. METHODS: To improve quality in accessing important literature findings, we developed a novel natural language processing (NLP) method to automatically recognize the associations among potential targeted host organ systems, associated clinical manifestations, and pathways. We further validated these associations through clinician experts' evaluations and prioritize candidate drug targets through bioinformatics network analysis. RESULTS: We found that the angiotensin-converting enzyme 2 (ACE2), a receptor that SARS-CoV-2 required for cell entry, is associated with cardiovascular and endocrine organ system and diseases. Furthermore, we found SARS-CoV-2 is associated with some important pathways such as IL-6, TNF-alpha, and IL-1 beta-induced dyslipidemia, which are related to inflammation, lipogenesis, and oxidative stress mechanisms, suggesting potential drug candidates. CONCLUSION: We prioritized the list of therapeutic targets involved in antiviral and immune modulating drugs for experimental validation, rendering it valuable during public health crises marked by stresses on clinical and research capacity. Our automatic intelligence pipeline also contributes to other novel and emerging disease management and treatments in the future.


Asunto(s)
COVID-19 , Humanos , Descubrimiento del Conocimiento , Procesamiento de Lenguaje Natural , Peptidil-Dipeptidasa A/metabolismo , SARS-CoV-2
16.
Nanotechnology ; 22(26): 265601, 2011 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-21576799

RESUMEN

Hierarchical nanostructured Bi(2)WO(6) micro-clews were synthesized by a solvothermal process with mixed solvents and formaldehyde. The hierarchical Bi(2)WO(6) micro-clews, with an average diameter of ca. 1.0 µm, consisted of nano-sheets assembled in a special fashion and the formation process mainly went through an Ostwald ripening-anisotropic growth and self-assembling process. The Bi(2)WO(6) micro-clews were further modified by Bi(2)O(3) to fabricate heterojunction photocatalysts, where Bi(2)O(3) nanoparticles were uniformly assembled on the surface of Bi(2)WO(6) nano-sheets. Compared with pure Bi(2)WO(6) and Bi(2)O(3), the composite photocatalyst exhibits higher photocatalytic activity for the degradation of rhodamine B under visible light. On the basis of characterization by x-ray diffraction, photoluminescence and UV-vis diffuse reflectance spectroscopies, a mechanism was proposed to account for the enhanced photocatalytic activity of the Bi(2)O(3)/Bi(2)WO(6) heterojunction.

17.
J Nanosci Nanotechnol ; 11(6): 4948-56, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21770127

RESUMEN

Bi2MoO6 hollow microspheres were successfully synthesized by a simple solvothermal process without using any hard template or surfactant. The effect of solvent and urea on the morphology of the samples was studied systematically. The results indicate that the composition of the mix ethylene glycol/absolute ethanol solvents and the urea content play a key role in the final formation of hollow microspheres. Based on the experimental results, the formation mechanism of the hollow interior by an EG-induced Ostwald ripening process was proposed for the Bi2MoO6 hollow microspheres. The Bi2MoO6 hollow microspheres exhibit higher catalytic activity than the Bi2MoO6 particles for degradation of Rhodamine B under visible-light irradiation (lambda > 420 nm). Further investigation revealed that the surface area, grain size, and hollow structure of the as-prepared Bi2MoO6 microspheres are responsible for the improvement of the photocatalytic activity.

18.
J Nanosci Nanotechnol ; 11(8): 6779-87, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22103080

RESUMEN

A novel kind of environmentally friendly nanocomposites, waterborne polyurethane (WBPU)/Cu(II)-loaded hydroxyapatite (CuHAp), with improved physical properties and antibacterial activity have been prepared via in-situ polymerization from functionalized CuHAp nanoparticles (CuHAp NPs). The interaction of the CuHAp NPs with isophorone diisocyanate to form the functionalized CuHAp NPs containing isocyanate groups (CuHAp-g-NCO) has been studied. The microstructure and particle distribution of the nanocomposites were observed using scanning electron microscopy. The improvements of mechanical properties, thermal stability and water resistance of the nanocomposites have also been evaluated. Finally, the antibacterial activity was tested against G(-) Escherichia coli and G(+) Staphylococcus aureus by the zone of inhibition test and the direct contact test. The long-lasting antibacterial activity was studied by measuring antibacterial ability of the nanocomposites after being immersed in water. The results indicate that WBPU incorporation with CuHAp NPs shows strong antibacterial activity upon contact, and long-lasting antibacterial property.


Asunto(s)
Antibacterianos/síntesis química , Antibacterianos/farmacología , Cobre/química , Durapatita/química , Nanocompuestos , Poliuretanos/química , Antibacterianos/química , Escherichia coli/efectos de los fármacos , Calor , Pruebas de Sensibilidad Microbiana , Microscopía Electrónica de Rastreo , Espectroscopía Infrarroja por Transformada de Fourier , Staphylococcus aureus/efectos de los fármacos
19.
J Colloid Interface Sci ; 596: 75-88, 2021 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-33838327

RESUMEN

Evolution of hydrogen from water by utilizing solar energy and photocatalysts is one of the most promising ways to solve energy crisis. However, designing a cost-effective and stable photocatalyst without any noble metals is of vital importance for this process. Herein, an extremely active molecular complex cocatalyst NiL2(Cl)2 is successfully designed. After being covalently linked to thiophene-embedded polymeric carbon nitride (TPCN), the hybrid catalyst NiL2(Cl)2/TPCN exhibits extraordinary H2 production activity of 95.8 µmol h-1 without Pt (λ ≥ 420 nm), together with a remarkable apparent quantum yield of 6.68% at 450 nm. In such a composite catalyst, the embedded π-electron-rich thiophene-ring not only extends the π-conjugated system to enhance visible light absorption, but also promotes the charge separation through electron-withdrawing effect. It turns out that the CN covalent bonds formed between NiL2(Cl)2 and TPCN skeleton accelerate the transfer of electrons to the Ni active sites. Our finding reveals that the strategy of embedding π-electron-rich compounds to graphitic carbon nitride provides potentials to develop excellent photocatalysts. The strong covalent combination of molecular complexes cocatalyst onto organic semiconductors represents an important step towards designing noble-metal-free photocatalysts with superior activity and high stability for visible light driven hydrogen evolution.

20.
Nanotechnology ; 21(31): 315502, 2010 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-20634566

RESUMEN

Triacetone triperoxide (TATP) is one of the most sensitive known explosives and can be easily synthesized using the commonly available chemicals acetone and hydrogen peroxide, but is difficult to be detected. In this study, In(2)O(3) nanoparticles were synthesized by a glucose-assisted solvothermal method at 120 degrees C for 18 h. The gas sensor based on In(2)O(3) nanoparticles exhibits a high response, fast response and recovery, a wide detecting range of 0.50-500 mg, good stability and excellent stability to TATP.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA