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1.
J Am Chem Soc ; 143(36): 14635-14645, 2021 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-34410692

RESUMEN

Antibodies are recognition molecules that can bind to diverse targets ranging from pathogens to small analytes with high binding affinity and specificity, making them widely employed for sensing and therapy. However, antibodies have limitations of low stability, long production time, short shelf life, and high cost. Here, we report a facile approach for the design of luminescent artificial antibodies with nonbiological polymeric recognition phases for the sensitive detection, rapid identification, and effective inactivation of pathogenic bacteria. Transition-metal dichalcogenide (TMD) nanosheets with a neutral dextran phase at the interfaces selectively recognized S. aureus, whereas the nanosheets bearing a carboxymethylated dextran phase selectively recognized E. coli O157:H7 with high binding affinity. The bacterial binding sites recognized by the artificial antibodies were thoroughly identified by experiments and molecular dynamics simulations, revealing the significance of their multivalent interactions with the bacterial membrane components for selective recognition. The luminescent WS2 artificial antibodies could rapidly detect the bacteria at a single copy from human serum without any purification and amplification. Moreover, the MoSe2 artificial antibodies selectively killed the pathogenic bacteria in the wounds of infected mice under light irradiation, leading to effective wound healing. This work demonstrates the potential of TMD artificial antibodies as an alternative to antibodies for sensing and therapy.


Asunto(s)
Antibacterianos/uso terapéutico , Infecciones por Escherichia coli/tratamiento farmacológico , Sustancias Luminiscentes/uso terapéutico , Nanoestructuras/uso terapéutico , Animales , Antibacterianos/química , Antibacterianos/efectos de la radiación , Dextranos/química , Escherichia coli O157/efectos de los fármacos , Escherichia coli O157/aislamiento & purificación , Luz , Sustancias Luminiscentes/química , Sustancias Luminiscentes/efectos de la radiación , Ratones , Simulación de Dinámica Molecular , Molibdeno/química , Molibdeno/efectos de la radiación , Molibdeno/uso terapéutico , Nanoestructuras/química , Nanoestructuras/efectos de la radiación , Terapia Fototérmica , Compuestos de Selenio/química , Compuestos de Selenio/efectos de la radiación , Compuestos de Selenio/uso terapéutico , Piel/microbiología , Espectrometría Raman , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/aislamiento & purificación , Sulfuros/química , Sulfuros/efectos de la radiación , Sulfuros/uso terapéutico , Compuestos de Tungsteno/química , Compuestos de Tungsteno/efectos de la radiación , Compuestos de Tungsteno/uso terapéutico , Cicatrización de Heridas/efectos de los fármacos
2.
Anal Chem ; 92(16): 10935-10939, 2020 08 18.
Artículo en Inglés | MEDLINE | ID: mdl-32806903

RESUMEN

An intramolecular photoelectrochemical (PEC) system is designed from the novel electron donor YYYHWRGWV (Y3-H) peptide ligand for the first time. The bifunctional nonapeptide cannot only rely on the HWRGWV sequence as a site-oriented immobilizer to recognize the crystallizable fragment (Fc) domains of the antibody but also acts as electron donors for PEC generation via three tyrosine (Y) of the N-terminal. The Bi2WO6/AgInS2 heterojunction with a significant visible-light absorption is utilized as a photoelectric generator, and the motivation is ascribed to a proven proposition, namely, that short-wavelength illuminant radiates proteins, causing a decline in bioactivity of immune protein. An innovative biosensor is fabricated using the above strategies for the detection of CYFRA21-1, a biomarker of squamous cell lung carcinoma. This sort of PEC-based sensing platform shows convincing experimental data and could be an effective candidate for clinical application in the future due to their extremely skillful conception.


Asunto(s)
Antígenos de Neoplasias/sangre , Biomarcadores de Tumor/sangre , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Queratina-19/sangre , Péptidos/química , Tirosina/química , Anticuerpos Inmovilizados/química , Anticuerpos Inmovilizados/inmunología , Antígenos de Neoplasias/inmunología , Biomarcadores de Tumor/inmunología , Bismuto/química , Electrones , Humanos , Indio/química , Indio/efectos de la radiación , Queratina-19/inmunología , Luz , Límite de Detección , Fotoquímica/métodos , Puntos Cuánticos/química , Puntos Cuánticos/efectos de la radiación , Compuestos de Plata/química , Compuestos de Plata/efectos de la radiación , Compuestos de Tungsteno/química , Compuestos de Tungsteno/efectos de la radiación
3.
Mikrochim Acta ; 187(6): 344, 2020 05 23.
Artículo en Inglés | MEDLINE | ID: mdl-32447460

RESUMEN

Based on WS2 quantum dots (QDs) as fluorescent signals and MnO2 nanosheets as second-order scattering (SOS) signals, a combination of fluorescence and scattered light was used to construct a ratio sensing platform for glutathione (GSH) detection. When MnO2 nanosheets are added to WS2 QDs, the fluorescence of WS2 QDs is quenched by MnO2 nanosheets through IFE. Large-sized MnO2 nanosheets increase the SOS of the system and gradually approach the fluorescence. After adding GSH to WS2 QDs-MnO2, the MnO2 nanosheets were decomposed into Mn2+. The disappearance of the characteristic absorption peak of the MnO2 nanosheets suppressed the IFE to WS2 QDs, resulting in the fluorescence recovery of WS2 QDs. The reduction in size of MnO2 nanosheets after decomposition results in a decrease in the SOS of the system. Therefore, the ratio detection of GSH is obtained through the fluorescence and SOS dual signal response. Under optimal experimental conditions, the value of F406/S648 is linearly related to the GSH concentration in the range 0 to 60 µM, and the limit of detection (LOD) of GSH is 0.12 µM. In addition, the system is also used for the determination of GSH in real water samples and human serum, with good analytical results. Graphical abstract Schematic principle of fluorescence/scattered light system based on WS2 QDs-MnO2 for GSH ratiometric detection.


Asunto(s)
Colorantes Fluorescentes/química , Glutatión/sangre , Compuestos de Manganeso/química , Óxidos/química , Puntos Cuánticos/química , Espectrometría de Fluorescencia/métodos , Agua Potable/análisis , Fluorescencia , Colorantes Fluorescentes/efectos de la radiación , Humanos , Límite de Detección , Puntos Cuánticos/efectos de la radiación , Sulfuros/química , Sulfuros/efectos de la radiación , Compuestos de Tungsteno/química , Compuestos de Tungsteno/efectos de la radiación
4.
J Hazard Mater ; 384: 121308, 2020 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-31585292

RESUMEN

There are increasing environmental concerns of serious pollution from emission of antibiotic wastewater. Herein, a series of direct Z-scheme WO2.72/ZnIn2S4 (WOZIS) hybrid photocatalysts composed of one-dimensional (1D) WO2.72 (WO) nanorods and two-dimensional (2D) ZnIn2S4 (ZIS) nanosheets have been designed and constructed for tetracycline hydrochloride (TCH) degradation without presence of solid-state electron mediators. The crystalline phase, chemical composition, morphology, optical properties and photocatalytic activity of the as-prepared samples were characterized by the XRD, XPS, SEM, HRTEM, BET, UV-vis DRS, and PL. Obviously, all the WOZIS hybrid photocatalysts exhibited significantly enhanced photocatalytic activity towards TCH degradation. Meanwhile, WOZIS-1 sample with WO/ZIS molar ratio of 1:1 showed the highest photocatalytic activity. The significantly enhanced photoactivity of WOZIS hybrid photocatalyst was due to Z-scheme charge separation mechanism based on the build of tight interfacial contacts between WO nanorods and ZIS nanosheets, thereby driving efficient charge separation. Moreover, the high photocatalytic stability of as-prepared WOZIS-1 hybrid sample was revealed through seven successive cycling reactions.


Asunto(s)
Antibacterianos/química , Nanotubos/química , Tetraciclina/química , Contaminantes Químicos del Agua/química , Catálisis/efectos de la radiación , Indio/química , Indio/efectos de la radiación , Luz , Nanotubos/efectos de la radiación , Oxidación-Reducción , Fotólisis , Sulfuros/química , Sulfuros/efectos de la radiación , Compuestos de Tungsteno/química , Compuestos de Tungsteno/efectos de la radiación , Aguas Residuales/química , Purificación del Agua/métodos , Zinc/química , Zinc/efectos de la radiación
5.
Anal Chim Acta ; 1082: 152-164, 2019 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-31472704

RESUMEN

Development of simultaneous bacteria detection and eradication with simple, rapid, and reusable material is important in addressing bacterial contamination issues. In this study, we utilized the expression of alkaline phosphatase (ALP) from bacteria to design fluorescence ON/OFF system for bacteria detection, also using metal oxide nanoparticle for obtaining antibacterial activity and recyclability. The fluorescent-based biosensor with antibacterial activity was prepared by intercalating ALP-sensitive polymer dot (PD) containing ß-cyclodextrin (ß-CD) onto montmorillonite (MMT) as loading matrix via ionic exchange reaction, followed by immobilization of magnetic iron oxide (Fe3O4) and NIR-responsive cesium tungsten oxide (CsWO3). The PD-ßCD-MMT/Fe3O4-CsWO3 nanocomposite exhibited strong fluorescence intensity, which was quenched in the presence of bacterial ALP (0-1000 U/L) due to hydrolysis of p-nitrophenyl phosphate (NPP) into p-nitrophenol (NP) in the hydrophobic site of ß-CD. Furthermore, the nanocomposite could detect both gram-negative Escherichia coli and gram-positive Staphylococcus aureus in the range of 101-107 CFU/mL (LOD 5.09 and 4.62 CFU/mL, respectively), and showed high antibacterial activity against bacteria by generating photothermal heat under 5 min NIR irradiation, causing damage to bacterial cells. This material also demonstrated recyclability via magnetic field exposure due to the presence of Fe3O4. In addition, the fluorescence can be recovered following pH shock and re-conjugation of ß-CD molecules. After 4 cycles, nanocomposite still showed stable photothermal effects and fluorescence-based bacteria detection. Thus, this reusable material offers promising approach for simultaneous bacteria detection and killing, which is simple, rapid, and effective.


Asunto(s)
Fosfatasa Alcalina/química , Antibacterianos/farmacología , Escherichia coli/aislamiento & purificación , Nanopartículas de Magnetita/química , Puntos Cuánticos/química , Staphylococcus aureus/aislamiento & purificación , Antibacterianos/química , Bentonita/química , Cesio/química , Cesio/efectos de la radiación , Colorimetría/instrumentación , Colorimetría/métodos , Equipo Reutilizado , Escherichia coli/efectos de los fármacos , Calefacción , Rayos Infrarrojos , Límite de Detección , Nanopartículas de Magnetita/efectos de la radiación , Pruebas de Sensibilidad Microbiana/instrumentación , Pruebas de Sensibilidad Microbiana/métodos , Nanocompuestos/química , Nitrofenoles/química , Compuestos Organofosforados/química , Polímeros/química , Staphylococcus aureus/efectos de los fármacos , Compuestos de Tungsteno/química , Compuestos de Tungsteno/efectos de la radiación , beta-Ciclodextrinas/química
6.
Chem Commun (Camb) ; 55(32): 4711-4714, 2019 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-30942240

RESUMEN

Induced circular dichroism (ICD) of polyoxomolybdates and polyoxotungstates was realized in three kinds of natural polysaccharide hydrogels possessing hierarchical chirality. Interestingly, the extrinsic chiral factors were dominant in ionic κ/ι-carrageenan hybrids, while the ICD of clusters was dominantly influenced by the intrinsic alternating bond length (ABL) distortions of polyoxometalates in agarose hybrid. The optical activity of the POMs shows sensitive response to multiple stimuli, such as temperature, K+ salts, UV irradiation and redox agents.


Asunto(s)
Carragenina/química , Hidrogeles/química , Molibdeno/química , Sefarosa/química , Compuestos de Tungsteno/química , Dicroismo Circular , Hidrogeles/efectos de la radiación , Luz , Conformación Molecular , Molibdeno/efectos de la radiación , Rotación Óptica , Oxidación-Reducción , Estereoisomerismo , Temperatura , Compuestos de Tungsteno/efectos de la radiación
7.
Environ Pollut ; 249: 36-44, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30878860

RESUMEN

Spiramycin is a widely used macrolide antibiotic and exists at high concentration in production wastewater. A thermal-acid hydrolytic pretreatment using silicotungstic acid (STA) under microwave (MW) irradiation was suggested to mitigate spiramycin from production wastewater. Positive correlations were observed between STA dosage, MW power, interaction time and the hydrolytic removal efficiencies, and an integrative equation was generalized quantitively. Rapid and complete removal 100 mg/L of spiramycin was achieved after 8 min of reaction with 1.0 g/L of STA under 200 W of MW irradiation, comparing to 30.1% by MW irradiation or 15.9% by STA alone. The synergetic effects of STA and MW irradiation were originated from the dissociated-proton catalysis by STA and the dipolar rotation heating effect of MW. STA performed much better than the mineral acid H2SO4 under MW, due to the much stronger Brönsted acidity and higher Hammett acidity. After 8 min, 98.0% of antibacterial potency was also reduced. The m/z 558.8614 fragment (P1) and m/z 448.1323 fragment (P2) were identified as the primary products, which were formed by breaking glucosidic bonds and losing mycarose and forosamine for P1 and further mycaminose moiety for P2. Finally, production wastewater with 433 mg/L of spiramycin was effectively treated using this thermal-acid hydrolytic method. Spiramycin and its antibacterial potency both dropped to 0 after 6 min. The potency drop was supposed from the losing of mycarose and/or forosamine. To decrease both the concentration of spiramycin and its antibacterial potency, combinedly using STA and MW was suggested in this work to break down the structural bonds of the functional groups rather than to destroy the whole antibiotic molecules. It is promising for pretreating spiramycin-contained production wastewater to mitigate both the antibiotic and its antibacterial potency.


Asunto(s)
Microondas , Silicatos/efectos de la radiación , Espiramicina/química , Compuestos de Tungsteno/efectos de la radiación , Antibacterianos/química , Catálisis , Hidrólisis , Aguas Residuales/química
8.
J Hazard Mater ; 359: 1-8, 2018 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-30007199

RESUMEN

Photodisinfection by semiconductors has been proven to be an effective method for achieving antibacterial or antifungal activity. However, the toxicity of the nanomaterial to the environment and organisms is a major concern. Herein, a highly efficient and environmentally friendly photodisinfection material of a carbon dots (CDs) decorated Na2W4O13 composite with WO3 photocatalyst was fabricated via a facile hydrothermal-calcination approach. The TEM (transmission electron microscopy) images showed that CDs decorated the surface of the Na2W4O13 flakes. Compared with the samples without incorporated CDs, the as-synthesized composite of CDs/Na2W4O13/WO3 exhibited excellent antimicrobial activity against E. coli under visible light illumination. Electron spin resonance (ESR) spectroscopy and reactive species scavenging experiments revealed that the hydroxyl radicals and superoxide radical anions played the most important role in the photocatalytic bacterial inactivation. Furthermore, the cytotoxicity of the CDs/Na2W4O13/WO3 composite was evaluated by analyzing the viability of HepG2 and Chinese hamster lung (V79) cells using Cell Counting Kit-8 (CCK-8).


Asunto(s)
Antibacterianos , Carbono , Luz , Compuestos de Tungsteno , Animales , Antibacterianos/química , Antibacterianos/farmacología , Antibacterianos/efectos de la radiación , Carbono/química , Carbono/farmacología , Carbono/efectos de la radiación , Catálisis , Línea Celular , Supervivencia Celular/efectos de los fármacos , Cricetulus , Escherichia coli/efectos de los fármacos , Escherichia coli/efectos de la radiación , Humanos , Radical Hidroxilo/química , Paladio/química , Procesos Fotoquímicos , Superóxidos/química , Compuestos de Tungsteno/química , Compuestos de Tungsteno/farmacología , Compuestos de Tungsteno/efectos de la radiación
9.
J Nanosci Nanotechnol ; 16(4): 3674-8, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27451687

RESUMEN

An electrostatically self-assembled multilayer thin film consisting of alternating layers of Keggin polyoxometalate of Zn-substituted tungstoborate (BW11Zn) and Rhodamine B (RhB) has successfully been prepared on a quartz and indium-tin oxide (ITO) glass substrate. The ultraviolet-visible (UV-vis) absorption spectra demonstrated that the electrostatically self-assembled film of (BW11Zn/RhB)n was uniformly deposited layer by layer, and the RhB molecules in the film formed the J-aggregation. The photoelectrochemical investigations showed that the films generated stable cathodic photocurrents that originated from RhB, and the maximal cathodic photocurrent density generated by an eight-layer film was 4.9 µA/cm2 while the film was irradiated with 100 mW/cm2 polychromatic light of 730 nm > λ > 325 nm at an applied potential of 0 V versus a saturated calomel electrode.


Asunto(s)
Boratos/química , Suministros de Energía Eléctrica , Electrodos , Galvanoplastia/métodos , Nanopartículas del Metal/química , Rodaminas/química , Compuestos de Tungsteno/química , Boratos/efectos de la radiación , Conductividad Eléctrica , Diseño de Equipo , Análisis de Falla de Equipo , Luz , Ensayo de Materiales , Membranas Artificiales , Nanopartículas del Metal/efectos de la radiación , Rodaminas/efectos de la radiación , Electricidad Estática , Compuestos de Tungsteno/efectos de la radiación , Zinc/química , Zinc/efectos de la radiación
10.
Appl Radiat Isot ; 114: 159-66, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27236832

RESUMEN

Novel, natural abundance metal disulfide targets were irradiated for 1h with a 10µA proton beam in a small, medical cyclotron. Osmium disulfide was synthesized by simple distillation and precipitation methods while MoS2 and WS2 were commercially available. The targets dissolved under mild conditions and were analyzed by γ-spectroscopy. Production rates and potential applications are discussed, including target recovery and recycling schemes for OsS2 and WS2.


Asunto(s)
Radioisótopos/aislamiento & purificación , Renio/aislamiento & purificación , Tecnecio/aislamiento & purificación , Ciclotrones , Disulfuros/efectos de la radiación , Humanos , Molibdeno/efectos de la radiación , Compuestos de Osmio/efectos de la radiación , Protones , Radiofármacos/aislamiento & purificación , Espectrometría gamma , Compuestos de Tungsteno/efectos de la radiación
11.
ChemSusChem ; 9(9): 996-1002, 2016 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-27059296

RESUMEN

Graphene-based ternary composite photocatalysts with genuine heterostructure constituents have attracted extensive attention in photocatalytic hydrogen evolution. Here we report a new graphene-based ternary composite consisting of CdS nanorods grown on hierarchical layered WS2 /graphene hybrid (WG) as a high-performance photocatalyst for hydrogen evolution under visible light irradiation. The optimal content of layered WG as a co-catalyst in the ternary CdS/WS2 /graphene composites was found to be 4.2 wt %, giving a visible light photocatalytic H2 -production rate of 1842 µmol h(-1) g(-1) with an apparent quantum efficiency of 21.2 % at 420 nm. This high photocatalytic H2 -production activity is due to the deposition of CdS nanorods on layered WS2 /graphene sheets, which can efficiently suppress charge recombination, improve interfacial charge transfer, and provide reduction active sites. The proposed mechanism for the enhanced photocatalytic activity of CdS nanorods modified with hierarchical layered WG was further confirmed by transient photocurrent response. This work shows that a noble-metal-free hierarchical layered WS2 /graphene nanosheets hybrid can be used as an effective co-catalyst for photocatalytic water splitting.


Asunto(s)
Compuestos de Cadmio/química , Hidrógeno/química , Nanotubos/química , Sulfuros/química , Compuestos de Tungsteno/química , Compuestos de Cadmio/efectos de la radiación , Catálisis , Grafito/química , Grafito/efectos de la radiación , Luz , Nanotubos/efectos de la radiación , Procesos Fotoquímicos , Sulfuros/efectos de la radiación , Compuestos de Tungsteno/efectos de la radiación
12.
J Hazard Mater ; 306: 295-304, 2016 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-26774984

RESUMEN

Photocatalytic degradation is an alternative method to remove pharmaceutical compounds in water, however it is hard to achieve efficient rate because of the poor solubility of pharmaceutical compounds in water. This study investigated the photodegradation of norfloxacin in a nonionic surfactant Triton-X100 (TX100)/Bi2WO6 dispersion under visible light irradiation (400-750nm). It was found that the degradation of poorly soluble NOF can be strongly enhanced with the addition of TX100. TX100 was adsorbed strongly on Bi2WO6 surface and accelerated NOF photodegradation at the critical micelle concentration (CMC=0.25mM). Higher TX100 concentration (>0.25mM) lowered the degradation rate. In the presence of TX100, the degradation rate reached the maximum value when the pH value was 8.06. FTIR analyses demonstrated that the adsorbed NOF on the catalyst was completely degraded after 2h irradiation. According to the intermediates identified by HPLC/MS/MS, three possible degradation pathways were proposed to include addition of hydroxyl radical to quinolone ring, elimination of piperazynilic ring in fluoroquinolone molecules, and replacement of F atoms on the aromatic ring by hydroxyl radicals.


Asunto(s)
Antibacterianos/química , Bismuto/química , Norfloxacino/química , Octoxinol/química , Tensoactivos/química , Compuestos de Tungsteno/química , Antibacterianos/toxicidad , Bismuto/efectos de la radiación , Catálisis , Escherichia coli/efectos de los fármacos , Luz , Norfloxacino/toxicidad , Fotólisis , Compuestos de Tungsteno/efectos de la radiación
13.
ChemSusChem ; 8(16): 2630-4, 2015 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-26130568

RESUMEN

To overcome the bottleneck of water splitting, the exploration of efficient, selective, and stable water oxidation catalysts (WOCs) is crucial. We report an all-inorganic, oxidatively and hydrolytically stable WOC based on a polyoxometalate [(A-α-SiW9 O34)2Co8(OH)6(H2O)2(CO3)3](16-) (Co8 POM). As a cobalt(II)-based cubane water oxidation catalyst, Co8POM embeds double Co(II)4O3 cores. The self-assembled catalyst is similar to the oxygen evolving complex (OEC) of photosystem II (PS II). Using [Ru(bpy)3](2+) as a photosensitizer and persulfate as a sacrificial electron acceptor, Co8POM exhibits excellent water oxidation activity with a turnover number (TON) of 1436, currently the highest among bioinspired catalysts with a cubical core, and a high initial turnover frequency (TOF). Investigation by several spectroscopy, spectrometry, and other techniques confirm that Co8POM is a stable and efficient catalyst for visible light-driven water oxidation. The results offer a useful insight into the design of water oxidation catalysts.


Asunto(s)
Cobalto/química , Complejos de Coordinación/química , Óxidos/química , Compuestos de Tungsteno/química , Materiales Biomiméticos , Catálisis , Cobalto/efectos de la radiación , Complejos de Coordinación/efectos de la radiación , Luz , Compuestos Organometálicos/química , Compuestos Organometálicos/efectos de la radiación , Oxidación-Reducción , Procesos Fotoquímicos , Fármacos Fotosensibilizantes/química , Fármacos Fotosensibilizantes/efectos de la radiación , Compuestos de Tungsteno/efectos de la radiación , Agua/química
14.
ChemSusChem ; 8(10): 1652-63, 2015 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-26018624

RESUMEN

In the search for stable and efficient photocatalysts beyond TiO2 , the tungsten-based oxide semiconductors silver tungstate (Ag2 WO4 ), copper tungstate (CuWO4 ), and zinc tungstate (ZnWO4 ) were prepared using solution combustion synthesis (SCS). The tungsten precursor's influence on the product was of particular relevance to this study, and the most significant effects are highlighted. Each sample's photocatalytic activity towards methyl orange degradation was studied and benchmarked against their respective commercial oxide sample obtained by solid-state ceramic synthesis. Based on the results herein, we conclude that SCS is a time- and energy-efficient method to synthesize crystalline binary tungstate nanomaterials even without additional excessive heat treatment. As many of these photocatalysts possess excellent photocatalytic activity, the discussed synthetic strategy may open sustainable materials chemistry avenues to solar energy conversion and environmental remediation.


Asunto(s)
Nanopartículas del Metal/química , Compuestos de Tungsteno/química , Compuestos Azo/química , Catálisis , Colorantes/química , Cobre/química , Cristalización , Luz , Nanopartículas del Metal/efectos de la radiación , Nanopartículas del Metal/ultraestructura , Microscopía Electrónica de Transmisión , Fotólisis , Plata/química , Soluciones , Compuestos de Tungsteno/efectos de la radiación , Zinc/química
15.
Nucl Med Biol ; 42(6): 530-5, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25805313

RESUMEN

A proof of concept study was undertaken where non-carrier added (186 g)Re was produced from the cyclotron bombardment of (186)WC. (186)WC was carbo-thermally generated from a novel precursor synthesized from (186)WO3, aqueous ammonia and hexamethyltetramine. The inherent high electrical and thermal conductivity of this material, coupled with its high melting point, made it an ideal candidate for proton bombardment for production of (186)Re. An18 µA irradiation for 3h and processing via thermo-chromatography, (186)WC yielded 0.93 mCi of (186 g)Re which corresponds to 89% of the calculated theoretical yields. The radiochemical purity of the desired (186 g)Re species was found to be between 95 and 97% with small contaminants of (186)ReO2. The radiochemistry utility of the product was investigated using S-benzoyl-MAG3, and 100% complexation was achieved with stability being maintained for 96 h. The re-oxidation of (186)WC back to(186)WO3 by oxygen in the thermo-chromatography method of processing ensured that the starting material was regenerated and recovered from the process in 94-98% yield.


Asunto(s)
Ciclotrones , Protones , Renio/química , Renio/aislamiento & purificación , Suero/química , Compuestos de Tungsteno/química , Compuestos de Tungsteno/efectos de la radiación , Glicina/análogos & derivados , Glicina/química , Humanos , Marcaje Isotópico , Radioquímica , Radiofármacos/química
16.
Dalton Trans ; 44(9): 3997-4002, 2015 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-25612008

RESUMEN

A new silver(I)-alkynyl cluster with a [Eu(W5O18)2](9-) polyoxoanionic core of [Ag42{Eu(W5O18)2}((t)BuC≡C)28Cl4] [OH]·H2O (1) has been designed and synthesized. The [Eu(W5O18)2](9-) polyoxoanion acts as a template to induce the formation of the surrounding 42-core Ag(I) cage. Due to the hydrophobic silver(I)-alkynyl shell, 1 features an unusual fluorescence enhancement as compared to the precursor of the [Eu(W5O18)2](9-) polyoxoanionic core. Interestingly, the silver ions in the shell silver(I)-alkynyl cage can only be reduced to silver atoms by irradiation with high energy UV light (2 kW). Upon high UV irradiation, fluorescence quenching of 1 has been observed. Moreover, the solution fluorescence of 1 can be modulated by addition of S(2-) ions into the system, which also leads to the fluorescence quenching phenomenon. The successful synthesis of 1 demonstrates a new route to the detection of high energy UV irradiation or S(2-) ions by elaborate design of fluorescence quenching of silver(I)-alkynyl clusters.


Asunto(s)
Europio/química , Plata/química , Compuestos de Tungsteno/química , Europio/efectos de la radiación , Fluorescencia , Plata/efectos de la radiación , Compuestos de Tungsteno/efectos de la radiación , Rayos Ultravioleta
17.
Dalton Trans ; 44(4): 1948-54, 2015 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-25492257

RESUMEN

Two polyoxometalate-based coordination polymers (POMCPs) constructed form Keggin POMs and Ag(+) with pyttz were synthesized: [Ag4(H2pyttz-I)(H2pyttz-II)(Hpyttz-II)][HSiW12O40]·4H2O (1) and [Ag4(H2pyttz-II)(Hpyttz-II)2][H2SiW12O40]·3H2O (2) (H2pyttz-I = 3-(pyrid-2-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl; H2pyttz-II = 3-(pyrid-4-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl). Both compounds have similar building units, similar stick-like units and similar 1D inorganic chains, but finally form the different motifs of tunnels (tunnel A in 1 and tunnel A&B in 2). By careful inspection of the structures of 1 and 2, it is believed that the isomerous pyttz molecules can precisely refine the structure of porous POMCPs without changing the underlying framework, which favors the study of the structure-activity relationship of POMCPs. Furthermore, the results of the photocatalytic activities show that compound 2 exhibits higher photocatalytic activity than that of compound 1, which is consistent with their structural characterization.


Asunto(s)
Complejos de Coordinación/química , Plata/química , Compuestos de Tungsteno/química , Catálisis , Complejos de Coordinación/efectos de la radiación , Estructura Molecular , Porosidad , Difracción de Polvo , Rodaminas/química , Plata/efectos de la radiación , Espectroscopía Infrarroja por Transformada de Fourier , Compuestos de Tungsteno/efectos de la radiación , Rayos Ultravioleta , Contaminantes Químicos del Agua/química , Difracción de Rayos X
18.
Opt Lett ; 39(16): 4635-8, 2014 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-25121836

RESUMEN

Under a 980 nm diode laser excitation, the near-infrared (NIR) emissions from Nd3+:4F7/2, 4F5/2, and 4F3/2 states in Nd3+/Yb3+ codoped CaWO4 powder were studied at temperatures ranging from 303 to 873 K. As the temperature increased, the NIR luminescence intensity was significantly enhanced and nearly 190-fold enhancement was achieved at 873 K compared with that at 303 K. By using the fluorescence intensity ratio technique, the thermometry behaviors through the NIR emissions were investigated. The results illustrate that the sensitivity and the accuracy achieved here are much higher than temperature sensors based on other rare earth ion doped materials.


Asunto(s)
Compuestos de Calcio/química , Niobio/química , Espectroscopía Infrarroja Corta/métodos , Termografía/métodos , Compuestos de Tungsteno/química , Iterbio/química , Compuestos de Calcio/efectos de la radiación , Rayos Infrarrojos , Láseres de Estado Sólido , Niobio/efectos de la radiación , Temperatura , Compuestos de Tungsteno/efectos de la radiación , Iterbio/efectos de la radiación
19.
Environ Sci Pollut Res Int ; 21(19): 11218-27, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24838128

RESUMEN

Decatungstate W10O32(4-) was efficiently intercalated between the layers of three-dimensionally ordered macroporous Mg2Al-layered double hydroxide. The structural and textural properties of as-prepared intercalated compound were characterized using different solid-state characterization techniques such as X-ray powder diffraction, FTIR and Raman spectroscopies and electronic microscopy. The photocatalytic properties of immobilized W10O32 (4-) within Mg2Al structure were investigated using 2-(1-naphthyl) acetamide (NAD) as a model of pesticide. The influence of different parameters such as amount of catalyst, pH and oxygen concentration were investigated. An optimal NAD degradation was obtained for a photocatalyst concentration of 60 mg l(-1). Under our experimental conditions, this heterogeneous photocatalyst induces photodegradation of 60 % of NAD after 17 h of irradiation at 365 nm and at pH 6.6. Interestingly, pesticide photodegradation leads to the mineralization of substrates to H2O and CO2 and the photocatalyst can be recycled and reused without any loss of activity over four cycles.


Asunto(s)
Hidróxidos/química , Sustancias Intercalantes/química , Ácidos Naftalenoacéticos/química , Plaguicidas/química , Compuestos de Tungsteno/química , Compuestos de Tungsteno/efectos de la radiación , Aluminio/química , Catálisis , Magnesio/química , Fotólisis , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría Raman , Difracción de Rayos X
20.
J Nanosci Nanotechnol ; 13(7): 4616-21, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23901482

RESUMEN

The tri-component hybrid CdS nanorods (NRs)/Au nanoparticles (NPs)@polyoxometalate (POM) was successfully prepared by a facile, efficient and green method. The structural properties and component analysis were studied by Transmission electron microscopy (TEM), X-ray Diffraction (XRD) and UV-Vis spectra. The POMs sever as not only reductant and bridge molecules, but also as co-catalyst to play an important role in the photocatalytic process. The as-prepared nanohybrid shows obviously enhanced photocatalytic activity toward photocatalytic evolution of hydrogen.


Asunto(s)
Compuestos de Cadmio/química , Oro/química , Hidrógeno/química , Nanopartículas del Metal/química , Nanotubos/química , Compuestos de Selenio/química , Compuestos de Tungsteno/química , Adsorción , Compuestos de Cadmio/efectos de la radiación , Catálisis , Oro/efectos de la radiación , Hidrógeno/aislamiento & purificación , Luz , Ensayo de Materiales , Nanopartículas del Metal/efectos de la radiación , Nanotubos/efectos de la radiación , Compuestos de Selenio/efectos de la radiación , Compuestos de Tungsteno/efectos de la radiación
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