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1.
Brief Bioinform ; 25(4)2024 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-39038939

RESUMEN

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder for which current treatments are limited and drug development costs are prohibitive. Identifying drug targets for ASD is crucial for the development of targeted therapies. Summary-level data of expression quantitative trait loci obtained from GTEx, protein quantitative trait loci data from the ROSMAP project, and two ASD genome-wide association studies datasets were utilized for discovery and replication. We conducted a combined analysis using Mendelian randomization (MR), transcriptome-wide association studies, Bayesian colocalization, and summary-data-based MR to identify potential therapeutic targets associated with ASD and examine whether there are shared causal variants among them. Furthermore, pathway and drug enrichment analyses were performed to further explore the underlying mechanisms and summarize the current status of pharmacological targets for developing drugs to treat ASD. The protein-protein interaction (PPI) network and mouse knockout models were performed to estimate the effect of therapeutic targets. A total of 17 genes revealed causal associations with ASD and were identified as potential targets for ASD patients. Cathepsin B (CTSB) [odd ratio (OR) = 2.66 95, confidence interval (CI): 1.28-5.52, P = 8.84 × 10-3], gamma-aminobutyric acid type B receptor subunit 1 (GABBR1) (OR = 1.99, 95CI: 1.06-3.75, P = 3.24 × 10-2), and formin like 1 (FMNL1) (OR = 0.15, 95CI: 0.04-0.58, P = 5.59 × 10-3) were replicated in the proteome-wide MR analyses. In Drugbank, two potential therapeutic drugs, Acamprosate (GABBR1 inhibitor) and Bryostatin 1 (CASP8 inhibitor), were inferred as potential influencers of autism. Knockout mouse models suggested the involvement of the CASP8, GABBR1, and PLEKHM1 genes in neurological processes. Our findings suggest 17 candidate therapeutic targets for ASD and provide novel drug targets for therapy development and critical drug repurposing opportunities.


Asunto(s)
Trastorno del Espectro Autista , Estudio de Asociación del Genoma Completo , Proteómica , Humanos , Trastorno del Espectro Autista/tratamiento farmacológico , Trastorno del Espectro Autista/genética , Trastorno del Espectro Autista/metabolismo , Animales , Ratones , Transcriptoma , Sitios de Carácter Cuantitativo , Mapas de Interacción de Proteínas/efectos de los fármacos , Ratones Noqueados , Terapia Molecular Dirigida
2.
Phys Rev Lett ; 132(15): 153402, 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38682986

RESUMEN

We report the first observation of the quantum Joule-Thomson (JT) effect in ideal and unitary Fermi gases. We study the temperature dynamics of these systems while they undergo an energy-per-particle conserving rarefaction. For scale-invariant systems, whose equations of state satisfy the relation U∝PV, this rarefaction conserves the specific enthalpy, which makes it thermodynamically equivalent to a JT throttling process. We observe JT heating in an ideal Fermi gas, a direct consequence of Pauli blocking. In a unitary Fermi gas, we observe that the JT heating is marginal in the temperature range 0.2≲T/T_{F}≲0.8 as the repulsive quantum-statistical effect is lessened by the attractive interparticle interactions.

3.
Angew Chem Int Ed Engl ; 63(9): e202317876, 2024 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-38193266

RESUMEN

Constructing uniform covalent organic framework (COF) film on substrates for electronic devices is highly desirable. Here, a simple and mild strategy is developed to prepare them by polymerization on a solid-liquid interface. The universality of the method is confirmed by the successful preparation of five COF films with different microstructures. These films have large lateral size, controllable thickness, and high crystalline quality. And COF patterns can also be directly achieved on substrates via hydrophilic and hydrophobic interface engineering, which is in favor of preparing device array. For application studies, the PyTTA-TPA (PyTTA: 4,4',4'',4'''-(1,3,6,8-Tetrakis(4-aminophenyl)pyrene and TPA: terephthalaldehyde) COF film has a high photoresponsivity of 59.79 µA W-1 at 420 nm for photoelectrochemical (PEC) detection. When employed as an active material for optoelectronic synaptic devices for the first attempt, it shows excellent light-stimulated synaptic plasticity properties such as short-term plasticity (STP), long-term plasticity (LTP), and the conversion of STP to LTP, which can be used to simulate biological synaptic functions.

4.
J Am Chem Soc ; 145(49): 26900-26907, 2023 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-38010167

RESUMEN

The manipulation of topological architectures in two-dimensional (2D) covalent organic framework (COF) materials for different applications is promising but remains a great challenge. Here, we first report the topology-selective synthesis of two distinct varieties of 2DCOFs, imine-based HT-COFs and benzimidazole-fused BI-HT-COFs, by simply altering acid catalysts. To HT-COFs, a superlattice of 1D channel with a persistent triangular shape is formed via Schiff base reaction, while to BI-HT-COFs, a hexagonal lattice structure with a highly conjugated structure and imidazole linkages is constructed due to an imine-based cyclization reaction. The two COFs exhibited marked differences in their bandgap, chemical stability, molecular adsorption, and catalytic activity, which make them have different fields of application. This work not only diversifies the hexaaminotriphenylene-based 2DCOF topologies but also provides vivid examples of structure-property relationships, which would facilitate fundamental research and potential applications of 2DCOFs.

5.
J Opt Soc Am A Opt Image Sci Vis ; 40(3): 427-442, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-37133009

RESUMEN

The offset linear canonical transform (OLCT) is an important research topic in many fields, and it has a more universal and elastic performance due to its extra parameters. However, although much work has been done concerning the OLCT, its fast algorithms are rarely addressed. In this paper, an O(N log⁡N) fast OLCT (FOLCT) algorithm that can significantly reduce the amount of calculation and improve accuracy is proposed. First, the discrete form of the OLCT is provided, and several important properties of its kernel are advanced. Next, the FOLCT based on the fast Fourier transform (FT) is derived for its numerical implementation. Then, the numerical results indicate that the FOLCT is a serviceable tool for signal analysis; additionally, the FOLCT algorithm can be used for the FT, fractional FT, linear canonical transform, and other transforms. Finally, its application to the detection of linear frequency modulated signals and optical image encryption, which is a basic case in signal processing, is discussed. The FOLCT can be effectively applied for the fast numerical calculation of the OLCT with valid and accurate results.

6.
Phys Rev Lett ; 129(20): 203402, 2022 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-36462022

RESUMEN

We report the creation and the study of the stability of a repulsive quasihomogeneous spin-1/2 Fermi gas with contact interactions. For the range of scattering lengths a explored, the dominant mechanism of decay is a universal three-body recombination toward a Feshbach bound state. We observe that the recombination coefficient K_{3}∝ε_{kin}a^{6}, where the first factor, the average kinetic energy per particle ε_{kin}, arises from a three-body threshold law, and the second one from the universality of recombination. Both scaling laws are consequences of Pauli blocking effects in three-body collisions involving two identical fermions. As a result of the interplay between Fermi statistics and the momentum dependence of the recombination process, the system exhibits nontrivial temperature dynamics during recombination, alternatively heating or cooling depending on its initial quantum degeneracy. The measurement of K_{3} provides an upper bound for the interaction strength achievable in equilibrium for a uniform repulsive Fermi gas.

7.
Int J Legal Med ; 136(4): 1181-1187, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35391604

RESUMEN

Allan-Herndon-Dudley syndrome (AHDS) is a very rare, X-linked psychomotor disability syndrome with delayed myelination, almost exclusively affecting boys. We present a case of a 4-year-old boy with AHDS who was found cyanotic, with intermittent vomiting and paroxysmal convulsions about 4 h after his parents went out, and was then taken to the hospital, where he eventually died the next day. The autopsy revealed foreign bodies in the tiny bronchi and alveoli of the deceased, congestion, and punctate hemorrhage in multiple organs, consistent with the diagnosis of asphyxia. Compared with a normally developing 4-year-old boy, the deceased showed cerebral atrophy and cerebral edema, and Luxol Fast Blue (LFB) stain indicated delayed cerebellar, hippocampal, and basal ganglia development and myelination. A novel frameshift mutation c.584delG in the SLC16A2 gene was detected. Family lineage investigation showed that the mutation was also detected in the deceased's 8-year-old brother and biological mother. The present work enriches the profile mutations in SLC16A2 related to AHDS and emphasizes the importance of autopsy and postmortem genetic analysis in such cases.


Asunto(s)
Discapacidad Intelectual Ligada al Cromosoma X , Simportadores , Niño , Preescolar , Mutación del Sistema de Lectura , Humanos , Masculino , Discapacidad Intelectual Ligada al Cromosoma X/diagnóstico , Discapacidad Intelectual Ligada al Cromosoma X/genética , Transportadores de Ácidos Monocarboxílicos/genética , Hipotonía Muscular , Atrofia Muscular , Mutación , Simportadores/genética
8.
Angew Chem Int Ed Engl ; 61(2): e202113067, 2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-34699115

RESUMEN

Facile synthesis and post-processing of covalent organic frameworks (COFs) under mild synthetic conditions are highly sought after and important for widespread utilizations in catalysis and energy storage. Here we report the synthesis of the chemically stable aza-fused COFs BPT-COF and PT-COF by a liquid-phase method. The process involves the spontaneous polycondensation of vicinal diamines and vicinal diketones, and is driven by the near-equilibrium growth of COF domains at a very low monomer concentration. The method permits in situ assembly of COFs and COF-GO hybrid materials and leads to the formation of a uniform conducting film on arbitrary substrates on vacuum filtration. When used as electrocatalysts, the as-prepared membranes show a fast hydrogen evolution reaction (HER) with a low overpotential (45 mV at 10 mA cm-2 ) and a small Tafel slope (53 mV dec-1 ), which are the best among metal-free catalysts. Our results may open a new route towards the preparation of highly π-conjugated COFs for multifunctional applications.

9.
Angew Chem Int Ed Engl ; 60(6): 2887-2891, 2021 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-33300656

RESUMEN

Owing to their excellent physical and electrical properties, metal-organic framework (MOF) materials with well-defined supramolecular structures have received extensive research attention. However, the fabrication of large-area two-dimensional (2D) MOF films is still a significant challenge. Herein, we propose a novel electrochemical (EC) synthesis method for the preparation of large-area Cu3 (HHTP)2 MOF film on single-crystal Cu (100) anode. The surface reaction was achieved via charge-induced molecular assembly. The synthesized MOF film exhibited a high crystalline quality with an electrical conductivity of approximately 0.087 S cm-1 , which was around 1000 times larger than the previously reported values for the same material prepared by the interface method. In addition, Cu2 (MTCP), Cu3 (BTPA)2 , and Cu3 (TPTC)2 MOF films were synthesized on Cu foil with the same strategy, which confirmed the universality of the proposed method. This controllable EC method can be effectively applied to the industrial-scale production of 2D MOF films on Cu foil.

10.
Angew Chem Int Ed Engl ; 60(32): 17440-17445, 2021 08 02.
Artículo en Inglés | MEDLINE | ID: mdl-34081388

RESUMEN

2D metal-organic framework (MOF) film as the active layer show promising application prospects in various fields including sensors, catalysis, and electronic devices. However, exploring the application of 2D MOF film in the field of artificial synapses has not been implemented yet. In this work, we fabricated a novel 2D MOF film (Cu-THPP, THPP=5,10,15,20-Tetrakis(4-hydroxyphenyl)-21H,23H-porphine), and further used it as an active layer to explore the application in the simulation of human brain synapses. It shows excellent light-stimulated synaptic plasticity properties, and exhibits the foundation function of synapses such as long-term plasticity (LTP), short-term plasticity (STP), and the conversion of STP to LTP. Most critically, the MOF based artificial synaptic device exhibits an excellent stability in atmosphere. This work opens the door for the application of 2D MOF film in the simulation of human brain synapses.


Asunto(s)
Materiales Biomiméticos/química , Membranas Artificiales , Estructuras Metalorgánicas/química , Materiales Biomiméticos/efectos de la radiación , Biomimética/métodos , Cobre/química , Cobre/efectos de la radiación , Luz , Estructuras Metalorgánicas/efectos de la radiación , Plasticidad Neuronal , Porfirinas/química , Porfirinas/efectos de la radiación , Sinapsis/química
11.
Nano Lett ; 18(6): 3377-3383, 2018 06 13.
Artículo en Inglés | MEDLINE | ID: mdl-29726254

RESUMEN

There is a huge demand for magnetoresistance (MR) sensors with high sensitivity, low energy consumption, and room temperature operation. It is well-known that spatial charge inhomogeneity due to impurities or defects introduces mobility fluctuations in monolayer graphene and gives rise to MR in the presence of an externally applied magnetic field. However, to realize a MR sensor based on this effect is hampered by the difficulty in controlling the spatial distribution of impurities and the weak magnetoresistance effect at the monolayer regime. Here, we fabricate a highly stable monolayer graphene-on-black phosphorus (G/BP) heterostructure device that exhibits a giant MR of 775% at 9 T magnetic field and 300 K, exceeding by far the MR effects from devices made from either monolayer graphene or few-layer BP alone. The positive MR of the G/BP device decreases when the temperature is lowered, indicating a phonon-mediated process in addition to scattering by charge impurities. Moreover, a nonlocal MR of >10 000% is achieved for the G/BP device at room temperature due to an enhanced flavor Hall effect induced by the BP channel. Our results show that electron-phonon coupling between 2D material and a suitable substrate can be exploited to create giant MR effects in Dirac semimetals.

12.
J Am Chem Soc ; 139(29): 10133-10141, 2017 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-28671465

RESUMEN

Sulfur is an attractive cathode material for next-generation lithium batteries due to its high theoretical capacity and low cost. However, dissolution of its lithiated product (lithium polysulfides) into the electrolyte limits the practical application of lithium sulfur batteries. Here we demonstrate that sulfur particles can be hermetically encapsulated by leveraging on the unique properties of two-dimensional materials such as molybdenum disulfide (MoS2). The high flexibility and strong van der Waals force in MoS2 nanoflakes allows effective encapsulation of the sulfur particles and prevent its sublimation during in situ TEM studies. We observe that the lithium diffusivities in the encapsulated sulfur particles are in the order of 10-17 m2 s-1. Composite electrodes made from the MoS2-encapsulated sulfur spheres show outstanding electrochemical performance, with an initial capacity of 1660 mAh g-1 and long cycle life of more than 1000 cycles.

13.
J Am Chem Soc ; 139(3): 1073-1076, 2017 01 25.
Artículo en Inglés | MEDLINE | ID: mdl-28051869

RESUMEN

We report the fast growth of high-quality millimeter-size monolayer MoSe2 crystals on molten glass using an ambient pressure CVD system. We found that the isotropic surface of molten glass suppresses nucleation events and greatly improves the growth of large crystalline domains. Triangular monolayer MoSe2 crystals with sizes reaching ∼2.5 mm, and with a room-temperature carrier mobility up to ∼95 cm2/(V·s), can be synthesized in 5 min. The method can also be used to synthesize millimeter-size monolayer MoS2 crystals. Our results demonstrate that "liquid-state" glass is a highly promising substrate for the low-cost growth of high-quality large-size 2D transition metal dichalcogenides (TMDs).

14.
J Insect Sci ; 17(2)2017 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-28365765

RESUMEN

RNA interference has been used to study insects' gene function and regulation. Glycogen synthase (GS) and glycogen phosphorylase (GP) are two key enzymes in carbohydrates' conversion in insects. Glycogen content and GP and GS gene expression in several tissues and developmental stages of the Brown planthopper Nilaparvata lugens Stål (Hemiptera: Delphacidae) were analyzed in the present study, using quantitative reverse-transcription polymerase chain reaction to determine their response to double-stranded trehalases (dsTREs), trehalose-6-phosphate synthases (dsTPSs), and validamycin injection. The highest expression of both genes was detected in the wing bud, followed by leg and head tissues, and different expression patterns were shown across the developmental stages analyzed. Glycogen content significantly decreased 48 and 72 h after dsTPSs injection and 48 h after dsTREs injection. GP expression increased 48 h after dsTREs and dsTPSs injection and significantly decreased 72 h after dsTPSs, dsTRE1-1, and dsTRE1-2 injection. GS expression significantly decreased 48 h after dsTPS2 and dsTRE2 injection and 72 h after dsTRE1-1 and dsTRE1-2 injection. GP and GS expression and glycogen content significantly decreased 48 h after validamycin injection. The GP activity significantly decreased 48 h after validamycin injection, while GS activities of dsTPS1 and dsTRE2 injection groups were significantly higher than that of double-stranded GFP (dsGFP) 48 h after injection, respectively. Thus, glycogen is synthesized, released, and degraded across several insect tissues according to the need to maintain stable trehalose levels.


Asunto(s)
Glucógeno Fosforilasa/genética , Glucógeno Sintasa/genética , Hemípteros/metabolismo , Proteínas de Insectos/genética , Trehalosa/metabolismo , Animales , Expresión Génica , Glucosiltransferasas/metabolismo , Glucógeno/metabolismo , Glucógeno Fosforilasa/metabolismo , Glucógeno Sintasa/metabolismo , Hemípteros/genética , Hemípteros/crecimiento & desarrollo , Inositol/análogos & derivados , Proteínas de Insectos/metabolismo , Microinyecciones , Especificidad de Órganos , Interferencia de ARN , Trehalasa/metabolismo
15.
Zhongguo Zhong Xi Yi Jie He Za Zhi ; 36(2): 149-54, 2016 Feb.
Artículo en Zh | MEDLINE | ID: mdl-27078988

RESUMEN

OBJECTIVE: To observe the efficacy and safety of modified Shengma Biejia Decoction (MSBD) combined with CAG program in treating elderly acute myeloid leukemia (AML) patients with yin deficiency toxin stasis syndrome (YDTSS). METHODS: Totally 46 elderly AML patients were assigned to the treatment group (24 cases; treated with MSBD + CAG) and the control group (22 cases; treated with CAG + placebos of Chinese medicine) according to random digit table. The therapeutic course of CM placebo or MSBD was 21 days. The clinical efficacy and adverse reactions were observed. Meanwhile, physical state (ECOG Score), transfusion dependency, and TCM syndrome score were compared before and after treatment. RESULTS: (1) The complete remission rate was 54% (13/24) and the objective response rate (ORR) was 71% (17/24) in the treatment group, obviously higher than those of the control group [36% (8/22); 54% (13/24)], with statistical difference (P = 0.036, 0.042). When comparing the efficacy based on risk level, the moderate and poor ORR was 71% (10/14) and 67% (6/9) in the treatment group, and 57% (8/14) and 33% (2/6) in the control group, with statistical difference between the two groups (P = 0.048; P = 0.010). (2) Compared with before treatment in the same group, the ECOG score significantly decreased, the average infusion time of red cells and platelets were markedly prolonged in the treatment group after treatment (P < 0.05). ECOG score, the average infusion time of red cells and platelets were significantly better in the treatment group than in the control group after treatment (P < 0.05). (3) Compared with before treatment in the same group, scores of fever, hemorrhage, and bone pain were markedly reduced in the control group (P < 0.05); scores of fever, fatigue, hemorrhage, dry mouth, and bone pain were markedly reduced in the treatment group (P < 0.05). Better effect in relief of fever, fatigue, hemorrhage, dry mouth, and so on was obtained in the treatment group than in the control group (P < 0.05). (4) In aspect of hematotoxicity, the incidence of neutropenia, anemia, thrombocytopenia was obviously lower in the treatment group than in the control group [29.2% (7/24) vs 54.5% (12/22); 16.7% (4/ 24) vs 45.5% (10/22); 33.3% (8/24) vs 63.6% (14/22); P < 0.05]. The incidence of fatigue and anorexia was obviously lower in the treatment group than in the control group [37.5% (9/24) vs 63.6% (14/22), 37.5% (9/24) vs 81.8% (18/22); P < 0.05]. CONCLUSION: MSBD combined with CAG program in treating elderly AML patients with YDTSS, with efficacy enhancing toxicity reducing effect, had distinct advantages in improving physical condition and clinical symptoms, and reducing transfusion dependency.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Medicamentos Herbarios Chinos/uso terapéutico , Leucemia Mieloide Aguda/tratamiento farmacológico , Fitoterapia , Deficiencia Yin/tratamiento farmacológico , Aclarubicina/uso terapéutico , Anciano , Citarabina/uso terapéutico , Factor Estimulante de Colonias de Granulocitos/uso terapéutico , Humanos , Medicina Tradicional China
16.
Phys Rev Lett ; 114(6): 065501, 2015 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-25723226

RESUMEN

Nanoscale corrugations are of great importance in determining the physical properties of two-dimensional crystals. However, the mechanical behavior of atomically thin films under strain is not fully understood. In this Letter, we show a layer-dependent mechanical response of molybdenum disulfide (MoS(2)) subject to atomistic-precision strain induced by 2H-bilayer island epitaxy. Dimensional crossover in the mechanical properties is evidenced by the formation of star-shaped nanoripple arrays in the first monolayer, while rippling instability is completely suppressed in the bilayer. Microscopic-level quantum mechanical simulations reveal that the nanoscale rippling is realized by the twisting of neighboring Mo-S bonds without modifying the chemical bond length, and thus invalidates the classical continuum mechanics. The formation of nanoripple arrays significantly changes the electronic and nanotribological properties of monolayer MoS(2). Our results suggest that quantum mechanical behavior is not unique for sp(2) bonding but general for atomic membranes under strain.

17.
Proc Natl Acad Sci U S A ; 109(21): 7992-6, 2012 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-22509001

RESUMEN

Unresolved problems associated with the production of graphene materials include the need for greater control over layer number, crystallinity, size, edge structure and spatial orientation, and a better understanding of the underlying mechanisms. Here we report a chemical vapor deposition approach that allows the direct synthesis of uniform single-layered, large-size (up to 10,000 µm(2)), spatially self-aligned, and single-crystalline hexagonal graphene flakes (HGFs) and their continuous films on liquid Cu surfaces. Employing a liquid Cu surface completely eliminates the grain boundaries in solid polycrystalline Cu, resulting in a uniform nucleation distribution and low graphene nucleation density, but also enables self-assembly of HGFs into compact and ordered structures. These HGFs show an average two-dimensional resistivity of 609 ± 200 Ω and saturation current density of 0.96 ± 0.15 mA/µm, demonstrating their good conductivity and capability for carrying high current density.


Asunto(s)
Cobre/química , Cristalización/métodos , Electrónica/métodos , Grafito/química , Nanotecnología/métodos , Ensayo de Materiales , Nanoestructuras/química , Tamaño de la Partícula , Cuarzo/química , Propiedades de Superficie
18.
J Am Chem Soc ; 135(17): 6431-4, 2013 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-23586921

RESUMEN

An anisotropic etching mode is commonly known for perfect crystalline materials, generally leading to simple Euclidean geometric patterns. This principle has also proved to apply to the etching of the thinnest crystalline material, graphene, resulting in hexagonal holes with zigzag edge structures. Here we demonstrate for the first time that the graphene etching mode can deviate significantly from simple anisotropic etching. Using an as-grown graphene film on a liquid copper surface as a model system, we show that the etched graphene pattern can be modulated from a simple hexagonal pattern to complex fractal geometric patterns with sixfold symmetry by varying the Ar/H2 flow rate ratio. The etched fractal patterns are formed by the repeated construction of a basic identical motif, and the physical origin of the pattern formation is consistent with a diffusion-controlled process. The fractal etching mode of graphene presents an intriguing case for the fundamental study of material etching.

19.
Anal Chem ; 85(21): 10091-8, 2013 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-24063353

RESUMEN

We developed a selective and sensitive hyphenated system employing a microfluidic-based vapor generation (VG) system in conjunction with high-performance liquid chromatography (HPLC) separation and inductively coupled plasma-mass spectrometry (ICPMS) detection for the determination of trace inorganic selenium (Se) species. The VG system exploited poly(methyl methacrylate) (PMMA) substrates of high optical quality to fabricate a microfluidic-based photocatalyst-assisted reduction device (microfluidic-based PCARD). Moreover, to reduce the consumption of photocatalysts during analytical procedures, a microfluidic-based PCARD coated with titanium dioxide nanoparticles (nano-TiO2) was employed to avoid consecutive loading. Notably, to simplify the coating procedure and improve the stability of the coating materials, a dynamic coating method was utilized. Under the optimized conditions for the selenicals of interest, the online HPLC/TiO2-coated microfluidic-based PCARD/ICPMS system enabled us to achieve detection limits (based on 3σ) of 0.043 and 0.042 µg L(-1) for Se(IV) and Se(VI), respectively. Both Se(IV) and Se(VI) could be efficiently vaporized within 15 s, while a series of validation experiments indicated that our proposed method could be satisfactorily applied to the determination of inorganic Se species in the environmental water samples.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Espectrometría de Masas/métodos , Microfluídica/instrumentación , Selenio/análisis , Titanio/química , Microscopía Electrónica de Rastreo
20.
Small ; 9(8): 1330-5, 2013 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-23463696

RESUMEN

Flake graphite is used as carbon source and ZnO or ZnS as catalyst in the synthesis of high-quality graphene sheets. A catalytic growth mechanism for cathode-part graphene synthesis in the arc-discharge apparatus and an exfoliation mechanism for wall-part graphene synthesis are introduced. N-doped cathode-part graphene and undoped wall-part graphene are formed simultaneously.

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