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1.
Zhongguo Dang Dai Er Ke Za Zhi ; 22(7): 744-748, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32669172

RESUMO

OBJECTIVE: To study the clinical features of children with severe adenovirus pneumonia (SAP) and hemophagocytic syndrome (HPS). METHODS: A retrospective analysis was performed from the chart review data of 30 children with SAP and HPS who were admitted from January 2014 to June 2019. According to the prognosis, the children were divided into a good prognosis group (n=18) and a poor prognosis group (n=12). RESULTS: Among the 30 children with SAP and HPS, the ratio of male to female was 2:1. The median age of onset was 1 year and 3 months (range 3 months to 5 years), and the mean course of fever was 19±7 d. Of the 30 children, 28 (93%) experienced disease onset in January to June. High-throughput gene detection of serum pathogens showed that 16 (53%) children were positive for human adenovirus type 7 (HAdV-7), and the other 14 (47%) children were positive for HAdV antigen based on immunofluorescence assay for throat swab, with unknown type. Of all 30 children, 29 (97%) had respiratory complications, 24 (80%) had cardiovascular complications, 16 (53%) had gastrointestinal complications, and 9 (30%) had toxic encephalopathy. Eighteen children (60%) improved or recovered and 12 (40%) did not recover (3 died). Compared with the good prognosis group, the poor prognosis group had a significantly longer course from onset to diagnosis of HPS (P<0.05), significantly higher levels of fibrinogen and tumor necrosis factor-α (P<0.05), and a significantly lower level of interferon-γ (P<0.05). The mean follow-up time was 6±2 months; 11 (41%) children recovered, 1 (4%) experienced recurrence of HPS, and 15 (56%) had the sequela of post-infectious bronchiolitis obliterans (PIBO). CONCLUSIONS: HPS may be observed in children with SAP, and PIBO is the most common sequela of SAP.


Assuntos
Infecções por Adenoviridae , Linfo-Histiocitose Hemofagocítica , Pneumonia Viral , Adenoviridae , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Estudos Retrospectivos
2.
Nat Commun ; 11(1): 1205, 2020 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-32139679

RESUMO

Since its invention in the 1960s, one of the most significant evolutions of metal-oxide-semiconductor field effect transistors (MOS-FETs) would be the three dimensionalized version that makes the semiconducting channel vertically wrapped by conformal gate electrodes, also recognized as FinFET. During the past decades, the width of fin (W[Formula: see text]) in FinFETs has shrunk from about 150 nm to a few nanometers. However, W[Formula: see text] seems to have been levelling off in recent years, owing to the limitation of lithography precision. Here, we show that by adapting a template-growth method, different types of mono-layered two-dimensional crystals are isolated in a vertical manner. Based on this, FinFETs with one atomic layer fin are obtained, with on/off ratios reaching [Formula: see text]. Our findings push the FinFET to the sub 1 nm fin-width limit, and may shed light on the next generation nanoelectronics for higher integration and lower power consumption.

3.
Adv Mater ; : e1907288, 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31977113

RESUMO

In a modern electronics system, charge-coupled devices and data storage devices are the two most indispensable components. Although there has been rapid and independent progress in their development during the last three decades, a cofunctionality of both sensing and memory at single-unit level is yet premature for flexible electronics. For wearable electronics that work in ultralow power conditions and involve strains, conventional sensing-and-memory systems suffer from low sensitivity and are not able to directly transform sensed information into sufficient memory. Here, a new transformative device is demonstrated, which is called "sen-memory", that exhibits the dual functionality of sensing and memory in a monolithic integrated circuit. The active channel of the device is formed by a carbon nanotube thin film and the floating gate is formed by a controllably oxidized aluminum nanoparticle array for electrical- and optical-programming. The device exhibits a high on-off current ratio of ≈106 , a long-term retention of ≈108 s, and durable flexibility at a bending strain of 0.4%. It is shown that the device senses a photogenerated pattern in seconds at zero bias and memorizes an image for a couple of years.

4.
Nat Commun ; 10(1): 4854, 2019 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-31649240

RESUMO

Nanocrystallization is a well-known strategy to dramatically tune the properties of materials; however, the grain-size effect of graphene at the nanometer scale remains unknown experimentally because of the lack of nanocrystalline samples. Here we report an ultrafast growth of graphene films within a few seconds by quenching a hot metal foil in liquid carbon source. Using Pt foil and ethanol as examples, four kinds of nanocrystalline graphene films with average grain size of ~3.6, 5.8, 8.0, and 10.3 nm are synthesized. It is found that the effect of grain boundary becomes more pronounced at the nanometer scale. In comparison with pristine graphene, the 3.6 nm-grained film retains high strength (101 GPa) and Young's modulus (576 GPa), whereas the electrical conductivity is declined by over 100 times, showing semiconducting behavior with a bandgap of ~50 meV. This liquid-phase precursor quenching method opens possibilities for ultrafast synthesis of typical graphene materials and other two-dimensional nanocrystalline materials.

5.
Nat Commun ; 10(1): 2809, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31243279

RESUMO

Large-area high-quality AB-stacked bilayer graphene films are highly desired for the applications in electronics, photonics and spintronics. However, the existing growth methods can only produce discontinuous bilayer graphene with variable stacking orders because of the non-uniform surface and strong potential field of the solid substrates used. Here we report the growth of wafer-scale continuous uniform AB-stacked bilayer graphene films on a liquid Pt3Si/solid Pt substrate by chemical vapor deposition. The films show quality, mechanical and electrical properties comparable to the mechanically exfoliated samples. Growth mechanism studies show that the second layer is grown underneath the first layer by precipitation of carbon atoms from the solid Pt, and the small energy requirements for the movements of graphene nucleus on the liquid Pt3Si enables the interlayer epitaxy to form energy-favorable AB stacking. This interlayer epitaxy also allows the growth of ABA-stacked trilayer graphene and is applicable to other liquid/solid substrates.

6.
Zhongguo Dang Dai Er Ke Za Zhi ; 21(6): 547-551, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31208507

RESUMO

OBJECTIVE: To study the serum lipid profile in children with different subtypes of juvenile idiopathic arthritis (JIA) during active and remission stages, as well as the long-term risk of atherosclerosis in children with JIA. METHODS: A total of 128 children newly diagnosed with active JIA were divided into oligoarticular JIA group with 48 children, polyarticular JIA group with 38 children, systemic JIA group with 22 children, and enthesitis-related JIA group with 20 children. According to the presence or absence of rheumatoid factor (RF), the polyarticular JIA group was further divided into RF-positive polyarticular JIA group with 15 children and RF-negative polyarticular JIA group with 23 children. A total of 45 children who underwent physical examination were randomly selected as healthy control group. The serum levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were measured and compared between groups. Blood lipid parameters were reexamined for 87 children in the remission stage after treatment and were compared with those in the active stage. RESULTS: Compared with the healthy control group, the systemic JIA group and the RF-positive polyarticular JIA group had a significant reduction in HDL-C and a significant increase in TG (P<0.05) in the active stage, while there were no significant differences in TC and LDL-C (P>0.05). There were no significant differences in blood lipid parameters between the other subtype JIA groups and the healthy control group (P>0.05). The RF-positive polyarticular JIA group had a significant increase in plasma HDL-C from the active stage to the remission stage (P<0.05), while the other subtype JIA groups had no significant changes in blood lipid parameters (P>0.05). CONCLUSIONS: Dyslipidemia may be observed in the active stage of children with systemic and RF-positive polyarticular JIA, with improvement in the remission stage of children with RF-positive polyarticular JIA. Further studies are needed to observe the long-term risk of atherosclerosis.


Assuntos
Artrite Juvenil , Criança , HDL-Colesterol , Humanos , Triglicerídeos
7.
ACS Nano ; 13(5): 5513-5522, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31013418

RESUMO

Clean transfer of two-dimensional (2D) materials grown by chemical vapor deposition is critical for their application in electronics and optoelectronics. Although rosin can be used as a support layer for the clean transfer of graphene grown on Cu, it has not been usable for the transfer of 2D materials grown on noble metals or for large-area transfer. Here, we report a poly(methyl methacrylate) (PMMA)/rosin double support layer that enables facile ultraclean transfer of large-area 2D materials grown on different metals. The bottom rosin layer ensures clean transfer, whereas the top PMMA layer not only screens the rosin from the transfer conditions but also improves the strength of the transfer layer to make the transfer easier and more robust. We demonstrate the transfer of monolayer WSe2 and WS2 single crystals grown on Au as well as large-area graphene films grown on Cu. As a result of the clean surface, the transferred WSe2 retains the intrinsic optical properties of the as-grown sample. Moreover, it does not require annealing to form good ohmic contacts with metal electrodes, enabling high-performance field effect transistors with mobility and ON/OFF ratio ∼10 times higher than those made by PMMA-transferred WSe2. The ultraclean graphene film is found to be a good anode for flexible organic photovoltaic cells with a high power conversion efficiency of ∼6.4% achieved.

8.
ACS Appl Mater Interfaces ; 11(12): 11699-11705, 2019 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-30839190

RESUMO

Carbon nanotube (CNT) thin-film transistors are expected to be promising for use in flexible electronics including flexible and transparent integrated circuits and in wearable chemical and physical sensors and for driving the circuits of flexible display panels. However, current devices based on CNT channels suffer from poor performance uniformity and low manufacturing yield; therefore, they are still far from being practical. This is usually caused by nonuniform deposition of the semiconducting CNTs and the rough surface of flexible substrates. Here, we report CNT thin-film transistors (TFTs) driving a flexible 64 × 64 pixel active matrix light-emitting diode display (AMOLED) by improving the formation of uniform CNT films and developing a new pretreatment technique for flexible substrates. The achieved AMOLED has uniform brightness and a high yield of 99.93% in its 4096 pixels. More than 8000 TFTs with high-purity semiconducting CNTs as the channel material show an average on-off current ratio of ∼107 and a carrier mobility of 16 cm2 V-1 s-1. The standard deviations of the on-state current and the carrier mobility are 4.1 and 6.5%, respectively. Our result shows that the panel driven by high-purity semiconducting CNTs is a promising strategy for the development of next-generation flexible, large-area displays.

9.
Nat Mater ; 18(1): 62-68, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30455446

RESUMO

Inorganic chalcogenides are traditional high-performance thermoelectric materials. However, they suffer from intrinsic brittleness and it is very difficult to obtain materials with both high thermoelectric ability and good flexibility. Here, we report a flexible thermoelectric material comprising highly ordered Bi2Te3 nanocrystals anchored on a single-walled carbon nanotube (SWCNT) network, where a crystallographic relationship exists between the Bi2Te3 <[Formula: see text]> orientation and SWCNT bundle axis. This material has a power factor of ~1,600 µW m-1 K-2 at room temperature, decreasing to 1,100 µW m-1 K-2 at 473 K. With a low in-plane lattice thermal conductivity of 0.26 ± 0.03 W m-1 K-1, a maximum thermoelectric figure of merit (ZT) of 0.89 at room temperature is achieved, originating from a strong phonon scattering effect. The origin of the excellent flexibility and thermoelectric performance of the Bi2Te3-SWCNT material is attributed, by experimental and computational evidence, to its crystal orientation, interface and nanopore structure. Our results provide insight into the design and fabrication of high-performance flexible thermoelectric materials.

10.
Adv Sci (Weinh) ; 5(5): 1700965, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29876218

RESUMO

This study reports a simple and effective technique for the high-throughput fabrication of flexible all-carbon nanotube (CNT) electronics using a photosensitive dry film instead of traditional liquid photoresists. A 10 in. sized photosensitive dry film is laminated onto a flexible substrate by a roll-to-roll technology, and a 5 µm pattern resolution of the resulting CNT films is achieved for the construction of flexible and transparent all-CNT thin-film transistors (TFTs) and integrated circuits. The fabricated TFTs exhibit a desirable electrical performance including an on-off current ratio of more than 105, a carrier mobility of 33 cm2 V-1 s-1, and a small hysteresis. The standard deviations of on-current and mobility are, respectively, 5% and 2% of the average value, demonstrating the excellent reproducibility and uniformity of the devices, which allows constructing a large noise margin inverter circuit with a voltage gain of 30. This study indicates that a photosensitive dry film is very promising for the low-cost, fast, reliable, and scalable fabrication of flexible and transparent CNT-based integrated circuits, and opens up opportunities for future high-throughput CNT-based printed electronics.

11.
Adv Mater ; 30(32): e1802057, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29952030

RESUMO

Single-wall carbon nanotubes (SWCNTs), especially in the form of large-area and high-quality thin films, are a promising material for use in flexible and transparent electronics. Here, a continuous synthesis, deposition, and transfer technique is reported for the fabrication of meter-scale SWCNT thin films, which have an excellent optoelectrical performance including a low sheet resistance of 65 Ω/◽ with a transmittance of 90% at a wavelength of 550 nm. Using these SWCNT thin films, high-performance all-CNT thin-film transistors and integrated circuits are demonstrated, including 101-stage ring oscillators. The results pave the way for the future development of large-scale, flexible, and transparent electronics based on CNT thin films.

12.
Sci Adv ; 4(5): eaap9264, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29736413

RESUMO

Single-wall carbon nanotubes (SWCNTs) are ideal for fabricating transparent conductive films because of their small diameter, good optical and electrical properties, and excellent flexibility. However, a high intertube Schottky junction resistance, together with the existence of aggregated bundles of SWCNTs, leads to a degraded optoelectronic performance of the films. We report a network of isolated SWCNTs prepared by an injection floating catalyst chemical vapor deposition method, in which crossed SWCNTs are welded together by graphitic carbon. Pristine SWCNT films show a record low sheet resistance of 41 ohm □-1 at 90% transmittance for 550-nm light. After HNO3 treatment, the sheet resistance further decreases to 25 ohm □-1. Organic light-emitting diodes using this SWCNT film as anodes demonstrate a low turn-on voltage of 2.5 V, a high current efficiency of 75 cd A-1, and excellent flexibility. Investigation of isolated SWCNT-based field-effect transistors shows that the carbon-welded joints convert the Schottky contacts between metallic and semiconducting SWCNTs into near-ohmic ones, which significantly improves the conductivity of the transparent SWCNT network. Our work provides a new avenue of assembling individual SWCNTs into macroscopic thin films, which demonstrate great potential for use as transparent electrodes in various flexible electronics.

13.
Nat Commun ; 8(1): 970, 2017 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-29042545

RESUMO

Atomically thin two-dimensional semiconducting materials integrated into van der Waals heterostructures have enabled architectures that hold great promise for next generation nanoelectronics. However, challenges still remain to enable their applications as compliant materials for integration in logic devices. Here, we devise a reverted stacking technique to intercalate a wrinkle-free boron nitride tunnel layer between MoS2 channel and source drain electrodes. Vertical tunnelling of electrons therefore makes it possible to suppress the Schottky barriers and Fermi level pinning, leading to homogeneous gate-control of the channel chemical potential across the bandgap edges. The observed features of ambipolar pn to np diode, which can be reversibly gate tuned, paves the way for future logic applications and high performance switches based on atomically thin semiconducting channel.Van der Waals heterostructures of atomically thin materials hold promise for nanoelectronics. Here, the authors demonstrate a reverted stacking fabrication method for heterostructures and devise a vertical tunnel-contacted MoS2 transistor, enabling gate tunable rectification and reversible pn to np diode behaviour.

14.
Adv Mater ; 29(29)2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28585225

RESUMO

The ultrafast growth of high-quality uniform monolayer WSe2 is reported with a growth rate of ≈26 µm s-1 by chemical vapor deposition on reusable Au substrate, which is ≈2-3 orders of magnitude faster than those of most 2D transition metal dichalcogenides grown on nonmetal substrates. Such ultrafast growth allows for the fabrication of millimeter-size single-crystal WSe2 domains in ≈30 s and large-area continuous films in ≈60 s. Importantly, the ultrafast grown WSe2 shows excellent crystal quality and extraordinary electrical performance comparable to those of the mechanically exfoliated samples, with a high mobility up to ≈143 cm2 V-1 s-1 and ON/OFF ratio up to 9 × 106 at room temperature. Density functional theory calculations reveal that the ultrafast growth of WSe2 is due to the small energy barriers and exothermic characteristic for the diffusion and attachment of W and Se on the edges of WSe2 on Au substrate.

15.
Adv Mater ; 29(32)2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28635068

RESUMO

A major obstacle for the use of single-wall carbon nanotubes (SWCNTs) in electronic devices is their mixture of different types of electrical conductivity that strongly depends on their helical structure. The existence of metal impurities as a residue of a metallic growth catalyst may also lower the performance of SWCNT-based devices. Here, it is shown that by using silicon oxide (SiOx ) nanoparticles as a catalyst, metal-free semiconducting and metallic SWCNTs can be selectively synthesized by the chemical vapor deposition of ethanol. It is found that control over the nanoparticle size and the content of oxygen in the SiOx catalyst plays a key role in the selective growth of SWCNTs. Furthermore, by using the as-grown semiconducting and metallic SWCNTs as the channel material and source/drain electrodes, respectively, all-SWCNT thin-film transistors are fabricated to demonstrate the remarkable potential of these SWCNTs for electronic devices.

16.
Adv Mater ; 29(16)2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28240393

RESUMO

Monolayer circular graphene platelets with a grain structure gradient in the radial direction are synthesized by chemical vapor deposition on immiscible W-Cu substrates. Because of the different interactions and growth behaviors of graphene on Cu and tungsten carbide, such substrates cause the formation of grain size and orientation gradients through the competition between Cu and tungsten carbide in graphene growth.

17.
Stem Cells Dev ; 26(2): 91-101, 2017 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-27832737

RESUMO

Endothelial progenitor cells/endothelial cells (EPCs/ECs) have great potential to treat pathological conditions such as cardiac infarction, muscle ischemia, and bone fractures, but isolation of EPC/ECs from existing cell sources is challenging due to their low EC frequency. We have isolated endothelial progenitor (EP)-like cells from rat oral mucosa and characterized their yield, immunophenotype, growth, and in vivo angiogenic potential. The frequency of EP-like cells derived from oral mucosa is thousands of folds higher than EPCs derived from donor-match bone marrow samples. EP-like cells from oral mucosa were positive for EC markers CD31, VE-Cadherin, and VEGFR2. Oral mucosa-derived EP-like cells displayed robust uptake of acetylated low-density lipoprotein and formed stable capillary networks in Matrigel. Subcutaneously implanted oral mucosa-derived EP-like cells anastomosed with host blood vessels, implicating their ability to elicit angiogenesis. Similar to endothelial colony-forming cells, EP-like cells from oral mucosa have a significantly higher proliferative rate than human umbilical vein endothelial cells. These findings identify a putative EPC source that is easily accessible in the oral cavity, potentially from discarded tissue specimens, and yet with robust yield and potency for angiogenesis in tissue and organ regeneration.


Assuntos
Células Endoteliais/citologia , Mucosa Bucal/citologia , Neovascularização Fisiológica , Regeneração , Animais , Aorta/citologia , Células da Medula Óssea/citologia , Células da Medula Óssea/efeitos dos fármacos , Contagem de Células , Proliferação de Células/efeitos dos fármacos , Separação Celular , Colágeno/farmacologia , Combinação de Medicamentos , Células Endoteliais/efeitos dos fármacos , Feminino , Citometria de Fluxo , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Cinética , Laminina/farmacologia , Camundongos Nus , Neovascularização Fisiológica/efeitos dos fármacos , Proteoglicanas/farmacologia , Ratos Sprague-Dawley , Ratos Transgênicos , Regeneração/efeitos dos fármacos
19.
Nat Commun ; 7: 11160, 2016 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-27025784

RESUMO

The growth of high-quality semiconducting single-wall carbon nanotubes with a narrow band-gap distribution is crucial for the fabrication of high-performance electronic devices. However, the single-wall carbon nanotubes grown from traditional metal catalysts usually have diversified structures and properties. Here we design and prepare an acorn-like, partially carbon-coated cobalt nanoparticle catalyst with a uniform size and structure by the thermal reduction of a [Co(CN)6](3-) precursor adsorbed on a self-assembled block copolymer nanodomain. The inner cobalt nanoparticle functions as active catalytic phase for carbon nanotube growth, whereas the outer carbon layer prevents the aggregation of cobalt nanoparticles and ensures a perpendicular growth mode. The grown single-wall carbon nanotubes have a very narrow diameter distribution centred at 1.7 nm and a high semiconducting content of >95%. These semiconducting single-wall carbon nanotubes have a very small band-gap difference of ∼0.08 eV and show excellent thin-film transistor performance.

20.
Nat Commun ; 6: 8569, 2015 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-26450174

RESUMO

Large-area monolayer WS2 is a desirable material for applications in next-generation electronics and optoelectronics. However, the chemical vapour deposition (CVD) with rigid and inert substrates for large-area sample growth suffers from a non-uniform number of layers, small domain size and many defects, and is not compatible with the fabrication process of flexible devices. Here we report the self-limited catalytic surface growth of uniform monolayer WS2 single crystals of millimetre size and large-area films by ambient-pressure CVD on Au. The weak interaction between the WS2 and Au enables the intact transfer of the monolayers to arbitrary substrates using the electrochemical bubbling method without sacrificing Au. The WS2 shows high crystal quality and optical and electrical properties comparable or superior to mechanically exfoliated samples. We also demonstrate the roll-to-roll/bubbling production of large-area flexible films of uniform monolayer, double-layer WS2 and WS2/graphene heterostructures, and batch fabrication of large-area flexible monolayer WS2 film transistor arrays.

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