Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 35
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Small ; 20(1): e2305185, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37649162

RESUMO

Phosphorescent materials with time-dependent phosphorescence colors (TDPCs) have great potential in advanced optical applications. Synthesis of such materials is attractive but challenging. Here, a series of carbon dot-porous Al2 O3 composites exhibiting distinctive TDPC characteristics is prepared by high-temperature pyrolysis of Al-based metal-organic frameworks NH2 -MIL-101(Al). The composite synthesized at 700 °C (CDs@Al2 O3 -700) shows an obvious change in phosphorescence color from blue to green after removing the excitation light of 280 nm. Photophysical analysis reveals that two emission centers in CDs, namely carbon core and surface states, are responsible for the short-lived blue phosphorescence (96 ms) and long-lived green phosphorescence (911 ms), respectively. The combination of blue and green phosphorescence with different decay rates triggering the interesting TDPC phenomenon. CDs@Al2 O3 -700 has a significantly high phosphorescence quantum yield of up to 41.7% and possesses an excellent optical stability against water, organic solvents, and strong oxidants, which benefits from the multi-confinement of CDs by the porous Al2 O3 matrix through rigid network, strong space constraint, and stable covalent bonding. Based on the TDPC property, multilevel coding patterns composed of CDs@Al2 O3 are successfully fabricated for advanced dynamic information encryption.

2.
Inorg Chem ; 61(48): 19240-19247, 2022 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-36394962

RESUMO

In this work, the composite electrode composed of metal-organic frameworks and transition metal phosphides is first assembled on the nickel foam substrate. The as-prepared NiCo-MOF-74@Ni12P5/NF exhibits excellent performances with ultrahigh specific capacitance (12.8 F/cm2 at 1 mA/cm2), stable charge-discharge rate (82.8%), and excellent cycling stability (reserve 73.90% after 5000 charge and discharge cycles at 30 mA/cm2), which are better than those of NiCo-MOF-74@NF without phosphating treatment of nickel foam. The corresponding hybrid supercapacitor (SC) device (NiCo-MOF-74@Ni12P5/NF//AC) delivers high storage capability (44.33 W·h/kg at 800 W/kg) and distinguished operating durability (83.04% after 5000 cycles). In addition, an all-solid-state hybrid SC successfully lit the LED for more than 2 min, which means that there is viable potential for practical applications in energy storage. The improved electrical properties are mainly due to the 3D heterostructure, the positive cooperative binding of nickel and cobalt elements, and the excellent electrical conductivity of the phosphide. As a result, this study proves the possibility of practical applications of NiCo-MOF-74@Ni12P5/NF electrodes for energy storage in hybrid SCs.

3.
Spectrochim Acta A Mol Biomol Spectrosc ; 269: 120734, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34922290

RESUMO

Sensitive determination of hypoxanthine (HX), an indicator reflecting the degradation of meat and fish, is significantly important in monitoring food freshness. Herein, we design a novel sensor consisting of orange emissive carbon dots (O-CDs), nitrotetrazolium blue chloride (NTBC), and xanthine oxidase (XOD) for fluorescence turn-off detection of HX. O-CDs, possessing a high fluorescence quantum yield of 37%, are synthesized by hydrothermal treatment of 2,3-diaminopyridine in sulfuric acid. NTBC can react with HX/XOD-generated H2O2 and O2- to yield a violet-colored formazan, which remarkably quenches the orange fluorescence of O-CDs through inner filter effect. There is a linearity between the quenching efficiency and HX concentration in the range of 2-250 µM, and the limit of detection is 0.61 µM, lower than those of most reported HX sensors. In addition, the proposed method exhibits excellent selectivity, and can be applied to quantify HX in fish samples with satisfactory results.


Assuntos
Carbono , Citrus sinensis , Animais , Corantes Fluorescentes , Peróxido de Hidrogênio , Hipoxantina
4.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120295, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34450572

RESUMO

Cerium, an abundant lanthanide element, is widely used in human industry. The accumulation of Ce4+ ion, however, will damage the environment and biological organism. Therefore, its facile detection is highly needed. Herein, we design a hybrid sensing platform consisting of carbon dots (C-dots) and bathophenanthroline-disulfonate-Fe2+ complex (Bphen-Fe2+) for trace-level determination of Ce4+. Based on inner filter effect (IFE), the red-colored Bphen-Fe2+ complex severely quenches the fluorescence of C-dots. After addition of Ce4+, Fe2+ is oxidized to Fe3+, and the colorless Bphen-Fe3+ complex generates, which weakens the IFE efficiency and leads to the fluorescence recovery of C-dots. Meanwhile, due to the decreasing amount of Bphen-Fe2+ upon Ce4+ addition, the red color of the solution gradually fades, which enables visual detection of Ce4+ by the naked eyes. Under the optimized conditions, the C-dots/Bphen-Fe2+ system realizes the fluorometric and colorimetric sensing of Ce4+ in the range of 0.5-100 and 1.9-80 µM, with the limits of detection as low as 0.5 and 1.9 µM, respectively. This method also shows high selectivity over other common ions, and has an excellent applicability for monitoring of Ce4+ in real water samples.


Assuntos
Cério , Pontos Quânticos , Carbono , Colorimetria , Humanos , Íons , Fenantrolinas
5.
Front Neuroergon ; 3: 1045653, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-38235475

RESUMO

Background: In the last decades, the P300 Speller paradigm was replicated in many experiments, and collected data were released to the public domain to allow research groups, particularly those in the field of machine learning, to test and improve their algorithms for higher performances of brain-computer interface (BCI) systems. Training data is needed to learn the identification of brain activity. The more training data are available, the better the algorithms will perform. The availability of larger datasets is highly desirable, eventually obtained by merging datasets from different repositories. The main obstacle to such merging is that all public datasets are released in various file formats because no standard way is established to share these data. Additionally, all datasets necessitate reading documents or scientific papers to retrieve relevant information, which prevents automating the processing. In this study, we thus adopted a unique file format to demonstrate the importance of having a standard and to propose which information should be stored and why. Methods: We described our process to convert a dozen of P300 Speller datasets and reported the main encountered problems while converting them into the same file format. All the datasets are characterized by the same 6 × 6 matrix of alphanumeric symbols (characters and numbers or symbols) and by the same subset of acquired signals (8 EEG sensors at the same recording sites). Results and discussion: Nearly a million stimuli were converted, relative to about 7000 spelled characters and belonging to 127 subjects. The converted stimuli represent the most extensively available platform for training and testing new algorithms on the specific paradigm - the P300 Speller. The platform could potentially allow exploring transfer learning procedures to reduce or eliminate the time needed for training a classifier to improve the performance and accuracy of such BCI systems.

6.
J Hazard Mater ; 411: 125184, 2021 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-33858118

RESUMO

Trace detection of fluoride ion has gained increasing attention due to fluoride's close association with biological and environmental processes. Herein, we construct a novel hybrid nanosystem consisting of carbon dots and curcumin for sensitive and selective sensing of F-. Carbon dots are synthesized by hydrothermal treatment of 2,3-diaminopyridine and selenourea in hydrochloric acid. This material is employed as the fluorescent indicator that exhibits intense blue and yellow emission with quantum yields of 12% and 33%, respectively. Curcumin, possessing an absorption peak at 532 nm, can significantly quench the yellow fluorescence of carbon dots through inner filter effect. Curcumin is also used to specifically recognize F-. When F- is added, the curcumin-F- complex generates, which leads to the hypochromatic shift of the absorption band from 532 to 430 nm. In such a case, the inner filter effect reduces, and yellow fluorescence of carbon dots recovers. Thus, a fluorescence turn-on sensor of F- is built based on the carbon dots/curcumin system. The limits of detection and quantitation are measured to be 0.39 and 1.30 µM, respectively. For real usage, the proposed method is applied to determinate F- in tap water and milk samples with relative standard deviations below 7.9%.


Assuntos
Curcumina , Pontos Quânticos , Carbono , Fluorescência , Corantes Fluorescentes , Fluoretos , Espectrometria de Fluorescência
7.
Food Chem ; 335: 127677, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32739822

RESUMO

Facile detection of malachite green (MG), a toxic dye, in aquaculture is urgently demanded for environment and food safety. Herein, we design a novel fluorescent probe, namely red emissive Se,N,Cl-doped carbon dots (CDs), to accurately determinate MG. CDs are prepared by hydrothermal treatment of selenourea and o-phenylenediamine in HCl solution. This material exhibits excitation-independent dual emissions at 625 and 679 nm, with a high quantum yield of 23.6%. A selective and sensitive fluorescent sensor toward MG is established based on inner filter effect, because both the excitation and emission light of CDs can be strongly absorbed by MG. The fluorescence quenching of CDs is linear to the MG concentration over the range of 0.07-2.50 µM with a low detection limit of 21 nM. Trace-level analysis of MG in fish tissue is successfully explored, demonstrating the great potential of the proposed sensor for MG monitoring in aquatic products.


Assuntos
Produtos Pesqueiros/análise , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Pontos Quânticos/química , Corantes de Rosanilina/análise , Animais , Carbono/química , Cloro/química , Fluorescência , Corantes Fluorescentes/química , Análise de Alimentos/instrumentação , Nitrogênio/química , Compostos Organosselênicos/química , Selênio/química , Espectrometria de Fluorescência , Ureia/análogos & derivados , Ureia/química
8.
Dalton Trans ; 49(30): 10535-10544, 2020 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-32691818

RESUMO

Transition metal sulfides are important candidates of battery-type electrode materials for advanced supercapatteries due to their high electric conductivity and electrochemical activity. The Co9S8@Ni3S2/ZnS composite microplate array was prepared by a metal-organic framework-assisted strategy because the electrochemical properties of composite arrays are governed by the synergistic effects of their diverse structures and compositions. As a battery-type material, the Co9S8@Ni3S2/ZnS electrode expressed an ultrahigh areal specific capacity of 8192 C cm-2 at the current density of 2 mA cm-2, and excellent cycling stability of 79.7% capacitance retention after 4000 cycles. An assembled supercapattery device using the Co9S8@Ni3S2/ZnS microplate array as a positive electrode and active carbon as the negative electrode delivered a high energy density of 0.377 mW h cm-2 at a high power density of 1.517 mW cm-2, and outstanding retention of 95.2% after 5000 cycles. As a result, the obtained Co9S8@Ni3S2/ZnS shows potential for applications in high-performance supercapattery.

9.
Spectrochim Acta A Mol Biomol Spectrosc ; 239: 118514, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-32470803

RESUMO

In this paper, we exploit an innovative strategy to reuse waste rubber tires as a low-cost source for the fabrication of a high-value material, fluorescent carbon dots (CDs). In the hydrothermal condition, ammonium persulphate is utilized to oxidize the tires and offer nitrogen atom for doping, to produce CDs with a high quantum yield (QY) of up to 23.8%. Such a QY is outstanding among the reported waste-derived CDs. It is found that the fluorescence of CDs can be remarkably quenched by Sudan I-IV with negligible interference from other substances. The corresponding linear ranges are 0.5-60, 0.5-60, 1-70, and 1-70 µM, and limits of detection are 0.17, 0.21, 0.53, and 0.62 µM for Sudan I, II, III, and IV, respectively. Systematic investigations reveal that the fluorescence quenching mainly stems from the inner filter effect. Moreover, the CD-based sensor shows an excellent applicability for the assay of Sudan dyes in chili powder sample.


Assuntos
Carbono , Pontos Quânticos , Corantes Fluorescentes , Limite de Detecção , Nitrogênio , Espectrometria de Fluorescência
10.
J Hazard Mater ; 388: 122073, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-31968303

RESUMO

Crystal violet (CV), a hazardous dye, poses a serious threat to the environment and human health. This motivates us to develop a facile method for its sensitive detection. Herein, we demonstrate a rapid sensing of CV using a novel fluorescent nanomaterial, yellow emissive Se,N-codoped carbon dots (CDs). CDs with an intense photoluminescence peak at 566 nm are synthesized by a hydrothermal technique using selenourea and o-phenylenediamine as precursors. This material shows a high quantum yield of up to 16.7 %. It is found that the yellow fluorescence of CDs can be selectively quenched by CV, which makes them promising for CV sensing. The linearity is obeyed in the range of 0.02-1.60 µM, and the limit of detection is as low as 7.3 nM. After detailed investigations, the inner filter effect is proposed to be the sensing mechanism. For practical usage, the newly built method is applied to determine the trace amount of CV in fish tissue samples, and satisfactory results are obtained.

11.
RSC Adv ; 10(23): 13922-13928, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35492998

RESUMO

Uniform one-dimensional metal oxide hollow tubular nanofibers (HTNs) have been controllably prepared using a calcination strategy using electrospun polymer nanofibers as soft templates and zeolitic imidazolate framework nanoparticles as precursors. Utilizing the general synthesis method, the ZnO HTNs, Co3O4 HTNs and ZnCo2O4 HTNs have been successfully prepared. The optimal ZnCo2O4 HTNs, as a representative substance applied in supercapacitors as the positive electrode, delivers a high specific capacity of 181 C g-1 at a current density of 0.5 A g-1, an excellent rate performance of 75.14% and a superior capacity retention of 97.42% after 10 000 cycles. Furthermore, an asymmetric supercapacitor assembled from ZnCo2O4 HTNs and active carbon also shows a stable and ultrahigh cycling stability with 95.38% of its original capacity after 20 000 cycle tests.

12.
RSC Adv ; 10(24): 14107-14112, 2020 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-35498489

RESUMO

Bismuth oxide (Bi2O3) with high specific capacity has emerged as a promising negative electrode material for supercapacitors (SCs). Herein, we propose a facile metal-organic framework (MOF) derived strategy to prepare Bi2O3 microrods with a carbon coat (Bi2O3@C). They exhibit ultrahigh specific capacity (1378 C g-1 at 0.5 A g-1) and excellent cycling stability (93% retention at 4000 cycles) when acting as negative electrode material for advanced asymmetric SCs. The assembled Bi2O3@C//CoNi-LDH asymmetric supercapacitor device exhibits a high energy density of 49 W h kg-1 at a power density of 807 W kg-1. The current Bi-MOF-derived strategy would provide valuable insights to prepare Bi-based inorganic nanomaterials for high-performance energy storage technologies and beyond.

13.
J Hazard Mater ; 382: 121048, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31476723

RESUMO

Million tons of sewage sludge produced yearly creates a severe pollution problem to environment, and thus needs either to be properly disposed of, or recovered. Here, we demonstrate a value-added utilization of sewage sludge by converting its contained organics into nanosized carbon dots (CDs) with microwave irradiation. This synthetic method, using waste resources as precursors and avoiding the requirement of hazardous reagents and complex procedures, has the great advantage of low cost, environmental friendliness, and easy scalability. The resultant CDs exhibit excellent fluorescence properties with a large quantum yield (QY) of up to 21.7%, higher than the most values of waste-derived CDs. It is found that CDs can serve as a sensitive and selective sensor to detect para-Nitrophenol (p-NP), a toxic pollutant, through fluorescence quenching, giving a linear detection range of 0.2-20 µM and a detection limit of as low as 0.069 µM. Systematic investigations suggest that the inner filter effect (IFE) is the dominant sensing mechanism. Moreover, the practical applications of CDs for p-NP assay in real water samples achieve good results.


Assuntos
Carbono/química , Micro-Ondas , Nitrofenóis/análise , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Fluorescência , Nitrofenóis/química , Esgotos , Poluentes Químicos da Água/química
14.
J Colloid Interface Sci ; 538: 481-488, 2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30537661

RESUMO

The increasing production of waste polyethylene terephthalate (PET) is a growing problem worldwide. Environmentally benign conversion of waste PET to valuable materials remains a substantial challenge. In this paper, we developed a green route to reuse waste PET for low-cost synthesis of fluorescent carbon dots (CDs) via air oxidation followed by hydrothermal treatment in aqueous H2O2 solution. No expensive, corrosive, or toxic reagents, or severe conditions were required in the synthetic process. The resultant CDs possessed abundant oxygenous groups and unique photoluminescence (PL) properties, which showed a highly selective and sensitive detection of ferric ion (Fe3+) through a PL quenching effect (on-off). The fluorescence of CDs quenched by Fe3+ could be restored specifically with pyrophosphate anion (PPi), rendering the CDs/Fe3+ sensor promising for PPi detection (off-on). The linear ranges for Fe3+ and PPi detections were 0.5-400 and 2-600 µM, and the limit of detections (LODs) were 0.21 and 0.86 µM, respectively. The sensing system applied for Fe3+ and PPi assays in real water samples and human urine achieved good results. After detailed investigations, a possible electron transfer process was proposed for explaining the "on-off-on" sensing mechanism.

15.
Nanoscale ; 7(38): 15953-61, 2015 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-26367253

RESUMO

In this work we designed a MoS2 nanoplate-based nanoprobe for fluorescence imaging of intracellular ATP and photodynamic therapy (PDT) via ATP-mediated controllable release of (1)O2. The nanoprobe was prepared by simply assembling a chlorine e6 (Ce6) labelled ATP aptamer on MoS2 nanoplates, which have favorable biocompatibility, unusual surface-area-to-mass ratio, strong affinity to single-stranded DNA, and can quench the fluorescence of Ce6. After the nanoprobe was internalized into the cells and entered ATP-abundant lysosomes, its recognition to ATP led to the release of the single-stranded aptamer from MoS2 nanoplates and thus recovered the fluorescence of Ce6 at an excitation wavelength of 633 nm, which produced a highly sensitive and selective method for imaging of intracellular ATP. Meanwhile, the ATP-mediated release led to the generation of (1)O2 under 660 nm laser irradiation, which could induce tumor cell death with a lysosomal pathway. The controllable PDT provided a model approach for design of multifunctional theranostic nanoprobes. These results also promoted the development and application of MoS2 nanoplate-based platforms in biomedicine.


Assuntos
Trifosfato de Adenosina/análise , Dissulfetos/química , Sondas Moleculares/química , Molibdênio/química , Nanoestruturas/química , Células HeLa , Humanos , Imagem Molecular , Fotoquimioterapia
16.
Langmuir ; 31(11): 3500-9, 2015 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-25741758

RESUMO

Bulk HgS itself has proven to be a technologically important material; however, the poor stability and weak emission of HgS nanocrystals have greatly hindered their promising applications. Presently, a critical problem is the uncontrollable growth of HgS NCs and their intrinsic surface states which are susceptible to the local environment. Here, we address the issue by an ion-tuning approach to fabricating stable, highly fluorescent Cd:HgS/CdS NCs for the first time, which efficiently tuned the band-gap level of HgS NCs, pushing their intrinsic states far away from the surface, reducing the strong interaction of the environment with surface states and hence drastically boosting the exciton transition. As compared to bare HgS NCs, the obtained Cd:HgS/CdS NCs exhibited tunable luminescence peaks from 724 to 825 nm with an unprecedentedly high quantum yield up to 40% at room temperature and excellent thermal and photostability. Characterized by TEM, XRD, XPS, and AAS, the resultant Cd:HgS/CdS NCs possessed a zinc-blende structure and was composed of a homogeneous alloyed HgCdS structure coated with a thin-layer CdS shell. The formation mechanism of Cd:HgS/CdS NCs was proposed. These bright, stable HgS-based NCs presented promising applications as fluorescent inks for anticounterfeiting and as excellent light converters when coated onto a blue-light-emitting diode.


Assuntos
Compostos de Cádmio/química , Nanopartículas/química
17.
Anal Chem ; 87(7): 3841-8, 2015 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-25739838

RESUMO

The integration of diagnostic and therapeutic functions in a single system holds great promise to enhance the theranostic efficacy and prevent the under- or overtreatment. Herein, a folate receptor-targeted and cathepsin B-activatable nanoprobe is designed for background-free cancer imaging and selective therapy. The nanoprobe is prepared by noncovalently assembling phospholipid-poly(ethylene oxide) modified folate and photosensitizer-labeled peptide on the surface of graphene oxide. After selective uptake of the nanoprobe into lysosome of cancer cells via folate receptor-mediated endocytosis, the peptide can be cleaved to release the photosensitizer in the presence of cancer-associated cathepsin B, which leads to 18-fold fluorescence enhancement for cancer discrimination and specific detection of intracellular cathepsin B. Under irradiation, the released photosensitizer induces the formation of cytotoxic singlet oxygen for triggering photosensitive lysosomal cell death. After lysosomal destruction, the lighted photosensitizer diffuses from lysosome into cytoplasm, which provides a visible method for in situ monitoring of therapeutic efficacy. The nanoprobe exhibits negligible dark toxicity and high phototoxicity with the cell mortality rate of 0.06% and 72.1%, respectively, and the latter is specific to folate receptor-positive cancer cells. Therefore, this work provides a simple but powerful protocol with great potential in precise cancer imaging, therapy, and therapeutic monitoring.


Assuntos
Catepsina B/metabolismo , Transportadores de Ácido Fólico/metabolismo , Nanopartículas/uso terapêutico , Neoplasias/diagnóstico , Neoplasias/tratamento farmacológico , Fármacos Fotossensibilizantes/metabolismo , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Endocitose , Células HeLa , Humanos , Células KB , Lisossomos/metabolismo , Nanopartículas/química , Nanopartículas/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Processos Fotoquímicos/efeitos da radiação , Fármacos Fotossensibilizantes/uso terapêutico , Oxigênio Singlete/metabolismo
18.
J Mater Chem B ; 3(27): 5608-5614, 2015 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32262531

RESUMO

A bottom-up method, using monoethanolamine (MEA) as both a passivation agent and a solvent, has been developed for rapid and massive synthesis of nitrogen-doped carbon dots (N-C-dots) from citric acid under heating conditions. This method requires a relatively mild temperature (170 °C) without special equipment, and affords one-pot large-scale production (39.96 g) of high-quality N-C-dots (quantum yield of 40.3%) in a few minutes (10 minutes). Significantly, an interesting formation process of N-C-dots, for the first time, has been monitored by transmission electron microscopy, ultraviolet-visible absorbance spectroscopy, photoluminescence spectroscopy, Fourier transformed infrared spectroscopy, and thermogravimetric analysis, and a corresponding formation mechanism, including polymerization, aromatization, nucleation, and growth, is proposed. It is important that the MEA-based synthesis of N-C-dots can be extended to various precursors, such as glucose, ascorbic acid, cysteine, and glutathione, which show general universality. Furthermore, the N-C-dots with strong fluorescence, excellent optical stability, and low cytotoxicity are successfully applied as fluorescent probes for bioimaging.

19.
J Mater Chem B ; 3(34): 6928-6938, 2015 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32262542

RESUMO

Near-infrared (NIR)-emitting nanocrystals have enormous potential as an enabling technology for applications ranging from tunable infrared lasers to biological labels. Mercury chalcogenide NCs are one of the attractive NCs with NIR emission; however, the potential toxicity of Hg restricts their diverse applications. Herein, we synthesized low-toxic, highly luminescent and stable GSH-capped HgS/ZnS core/shell NCs by an aqueous route for the first time. The core/shell structure was characterized by using TEM, XRD and XPS, which provide evidence for the shell growth. After the successful growth of an appropriate ZnS shell around HgS NCs, poorly luminescent HgS NCs converted into ultra-bright HgS/ZnS NCs, substantially increasing photoluminescence quantum yield up to 43.8% at room temperature. The fluorescence peak of HgS/ZnS NCs was successfully tuned in a wide NIR window ranging from 785 nm to 1060 nm with high emission efficiency by controlling the synthetic pH values. Significantly, an in vitro cytotoxicity study clearly demonstrated that the HgS/ZnS NCs exhibited good biocompatibility as evidenced by the cell viability retained above 80% at a dose of HgS/ZnS NCs up to 150 µg mL-1. More importantly, the low-toxic NIR-emitting HgS/ZnS NCs have proved to be an effective fluorescent label in in vitro and in vivo imaging. The penetration depth reached 2 cm in a nude mouse with distinct separation of autofluorescence and NCs' fluorescence, giving excellent contrast at all depths. The novel highly-luminescent NIR-emitting HgS/ZnS NCs open up new possibilities for highly-sensitive, highly spectrally resolved and multicolor imaging in biomedical applications.

20.
Can J Surg ; 56(4): E91-7, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23883510

RESUMO

BACKGROUND: Surgical simulators provide a safe environment to learn and practise psychomotor skills. A goal for these simulators is to achieve high levels of fidelity. The purpose of this study was to develop a reliable surgical simulator fidelity questionnaire and to assess whether a newly developed virtual haptic simulator for fixation of an ulna has comparable levels of fidelity as Sawbones. METHODS: Simulator fidelity questionnaires were developed. We performed a stratified randomized study with surgical trainees. They performed fixation of the ulna using a virtual simulator and Sawbones. They completed the fidelity questionnaires after each procedure. RESULTS: Twenty-two trainees participated in the study. The reliability of the fidelity questionnaire for each separate domain (environment, equipment, psychological) was Cronbach α greater than 0.70, except for virtual environment. The Sawbones had significantly higher levels of fidelity than the virtual simulator (p < 0.001) with a large effect size difference (Cohen d < 1.3). CONCLUSION: The newly developed fidelity questionnaire is a reliable tool that can potentially be used to determine the fidelity of other surgical simulators. Increasing the fidelity of this virtual simulator is required before its use as a training tool for surgical fixation. The virtual simulator brings with it the added benefits of repeated, independent safe use with immediate, objective feedback and the potential to alter the complexity of the skill.


CONTEXTE: Les simulateurs chirurgicaux offrent un environnement sécuritaire pour apprendre et pour exercer les habiletés psychomotrices. L'un des objectifs de ces simu - lateurs est de produire des degrés élevés de fidélité. Le but de cette étude était de mettre au point un questionnaire fiable sur la fidélité des simulateurs chirurgicaux et de vérifier si un nouveau simulateur virtuel, avec interface haptique, pour la fixation du cubitus présentait des taux de fidélité comparables à ceux du simulateur Sawbones. MÉTHODES: Des questionnaires sur la fidélité des simulateurs ont été préparés. Nous avons procédé à une étude randomisée stratifiée auprès de stagiaires en chirurgie qui ont effectué une fixation du cubitus à l'aide du simulateur virtuel et à l'aide du simulateur Sawbones. Ils ont répondu au questionnaire sur la fidélité après chaque intervention. RÉSULTANTS: Vingt-deux stagiaires ont participé à l'étude. La fiabilité du questionnaire sur la fidélité pour chaque domaine distinct (environnement, équipement, dimension psychologique) correspondait à un coefficient α Cronbach supérieur à 0,70, sauf pour ce qui est de l'environnement virtuel. Le simulateur Sawbones a présenté des taux de fidélité significativement plus élevés que le simulateur virtuel (p < 0,001), avec une différence importante au plan de la taille de l'effet (indice d de Cohen < 1,3). CONCLUSIONS: Le nouveau questionnaire sur la fidélité s'est révélé un outil fiable qui peut servir à déterminer le degré de fidélité d'autres simulateurs chirurgicaux. Il faudra améliorer la fidélité de ce simulateur virtuel avant de pouvoir l'utiliser comme outil de formation pour la fixation chirurgicale. Ce simulateur virtuel a l'avantage de permettre des utilisations sécuritaires répétées et indépendantes avec des résultats immédiats et objectifs et de modifier la complexité de l'habileté.


Assuntos
Simulação por Computador , Fixação de Fratura , Ortopedia/educação , Fraturas da Ulna/cirurgia , Avaliação Educacional , Estudos de Viabilidade , Humanos , Modelos Biológicos , Reprodutibilidade dos Testes , Inquéritos e Questionários
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA