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1.
Nat Commun ; 12(1): 1619, 2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33712614

RESUMO

The study of lanthanide (Ln)-transition-metal (TM) heterometallic clusters which play key roles in various high-tech applications is a rapid growing field of research. Despite the achievement of numerous Ln-TM cluster compounds comprising one Ln atom, the synthesis of Ln-TM clusters containing multiple Ln atoms remains challenging. Here, we present the preparation and self-assembly of a series of Au-bridged heterometallic clusters containing multiple cerium (Ce) atoms via on-surface coordination. By employing different pyridine and nitrile ligands, the ordered coordination assemblies of clusters containing 2, 3 and 4 Ce atoms bridged by Au adatoms are achieved on Au(111) and Au(100), as revealed by scanning tunneling microscopy. Density functional theory calculations uncover the indispensable role of the bridging Au adatoms in constructing the multi-Ce-containing clusters by connecting the Ce atoms via unsupported Ce-Au bonds. These findings demonstrate on-surface coordination as an efficient strategy for preparation and organization of the multi-Ln-containing heterometallic clusters.

2.
Sci Total Environ ; 778: 146107, 2021 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-33714091

RESUMO

A new method is presented for measuring atmospheric contents and δ34S-SO42- in airborne particulate matter using quartz wool disk passive air samplers (Pas-QW). The ability of Pas-QW samplers to provide time-integrated measurements of atmospheric SO42- was confirmed in a field calibration study. The average sampling rate of SO42- measured was 2.3 ± 0.3 m3/day, and this was not greatly affected by changes in meteorological parameters. The results of simultaneous sampling campaign showed that the average SO42- contents in Pakistan and the Indochina Peninsula (ICP) were relatively lower than that of China. The spatial distribution of SO42- concentrations was largely attributed to the development of the regional economies. The range of δ34S values observed in Pakistan (4.3 ± 1.4‰) and the ICP (4.5 ± 1.2‰) were relatively small, while a large range of δ34S values was observed in China (3.9 ± 2.5‰). The regional distribution of sulfur isotope compositions was significantly affected by coal combustion. A source analysis based on a Bayesian mixing model showed that 80.4 ± 13.1% and 19.6 ± 13.1% of artificial sulfur dioxide (SO2) sources in China could be attributed to coal combustion and oil combustion, respectively. The two sources differed greatly between regions, and the contribution of oil combustion in cities was higher than previously reported data obtained from emission inventories. This study confirmed that the Pas-QW is a promising tool for simultaneously monitoring atmospheric δ34S-SO42- over large regions, and that the results of the isotope models can provide a reference for the compilation of SO2 emission inventories.

3.
ACS Nano ; 2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33734662

RESUMO

The rapid development of integrated circuits and electronic devices creates a strong demand for highly thermally conductive yet electrically insulating composites to efficiently solve "hot spot" problems during device operation. On the basis of these considerations, hexagonal boron nitride nanosheets (BNNS) have been regarded as promising fillers to fabricate polymer matrix composites. However, so far an efficient approach to prepare ultrahigh-aspect-ratio BNNS with large lateral size while maintaining an atomically thin nature is still lacking, seriously restricting further improvement of the thermal conductivity for BNNS/polymer composites. Here, a rapid and high-yield method based on a microfluidization technique is developed to obtain exfoliated BNNS with a record high aspect ratio of ≈1500 and a low degree of defects. A foldable and electrically insulating film made of such a BNNS and poly(vinyl alcohol) (PVA) matrix through filtration exhibits an in-plane thermal conductivity of 67.6 W m-1 K-1 at a BNNS loading of 83 wt %, leading to a record high value of thermal conductivity enhancement (≈35 500). The composite film then acts as a heat spreader for heat dissipation of high-power LED modules and shows superior cooling efficiency compared to commercial flexible copper clad laminate. Our findings provide a practical route to produce electrically insulating polymer composites with high thermal conductivity for thermal management applications in modern electronic devices.

4.
Nanotechnology ; 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33652420

RESUMO

Thermal interface material (TIM) is pivotal for the heat dissipation between layers of high-density electronic packaging. The most widely used TIMs are the particle-filled composite materials, in which the highly conductive particulate fillers are added into the polymer matrix to promote the heat conduction. The numerical simulation of heat transfer in the composites is essential for the design of TIMs, however, the widely used finite element method requires large memory and presents limited computational time for the composites with dense particles. In this work, a numerical homogenization algorithm based on fast Fourier transform was adopted to estimate the thermal conductivity of composites with randomly dispersed particles in 3D space. The unit cell problem is solved by means of a polarization based iterative scheme, which can accelerate the convergence procedure regardless of the contrast between various components. The algorithm shows good precision and requirs dramatically reduced computation time and cost comparing with finite element method. Moreover, the effect of particle volume fraction, interface thermal resistance between particles (R-PP), interface thermal resistance between particle and matrix (R-PM), and particle size have been estimated. It turns out that the effective conductivity of the particulate composites increases sharply at a critical filler volume fraction, after which it is sensitive to the variation of filler loading. We can observe that the effective thermal conductivity of the composites with low filler volume fraction is sensitive to R-PM, whereas the it is governed by R-PP for the compsosites with high filler content. The algorithm presents excellent efficiency and accuracy, showing potential for the future design of highly thermally conductive TIMs.

5.
J AOAC Int ; 2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33757128

RESUMO

BACKGROUND: The direct injection gas chromatography is convenient and quick, and the residual solvent with a higher boiling point can be measured, which is developed for residual solvents analysis of Sorafenib Tosylate. OBJECTIVE: In the present investigation, the injection method was developed and validated for the detection and quantification of residual solvents in Sorafenib Tosylate. METHODS: The nine kinds of residual solvents were separated using direct injection gas chromatographic technology, and a quantitative analysis was performed. Analytical performance of the proposed injection method was validated as per the defined guidelines with respect to linearity, accuracy, precision, robustness, and specificity. RESULTS: Under the optimized conditions, simultaneous separation and determination of nine kinds of residual solvents, including methanol, acetonitrile, ethyl acetate, tetrahydrofuran, chlorobenzene, toluene, acetone, dichloromethane and N, N-dimethylformamide were carried out by using a DB-WAXETR Polyethylene glycol INERTCAP PURE-WAX column (30 m × 0. 32 mm × 0.25 µm) for separation. The calibration plot was found to be linear, accurate, precise, robust, and specific for direct injection gas chromatography. The residual solvents in Sorafenib Tosylate were quantified by the developed method. CONCLUSIONS: The present method was successfully applied for analysis of residual solvents in Sorafenib Tosylate. Similarly, the method can be used for quality control and stability testing of other medicines. HIGHLIGHTS: a validated GC assay for the combined analysis of the nine solutions which offered a reference method for the detection of residual solvents in other medicines.

6.
Medicine (Baltimore) ; 100(5): e24526, 2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33592906

RESUMO

BACKGROUND: Dementia, a kind of acquired and progressive intelligence-damaging syndrome, is induced by cerebral dysfunction. Ancient records show that Qi Fu Yin (QFY) has the advantages in age-related dementia treatment. This study aims to evaluate therapeutic efficacy of QFY on dementia through meta-analysis. METHODS: We comprehensively reviewed articles from various databases, including China National Knowledge Infrastructure (CNKI), Wanfang, VIP, Chinese Biomedical Literature (CBM), PubMed, and Web of Science published before June 2020, for all randomized controlled trials (RCTs) on dementia treatment with QFY. Then, we selected eligible literatures, extracted related data, and assessed risk of bias. Forest plots of total clinical effective rate, MMSE score, HDS score and ADL score illustrated the difference between the experimental group (treatment with QFY alone or combined with routine western medicine) and the control group (treatment with routine western medicine only). Random effects model and fixed effects model were adopted. Finally, publication bias was further analyzed using funnel plot, sensitivity analysis, Begg and Egger test. RESULTS: Finally, 9 RCTs, involving 697 patients, were included in this study. The results revealed that the total clinical effective rate of the experimental group was obviously higher than that of the control group (OR = 0.33, 95% CI [0.22, 0.50], P < .001). In comparison with the control group, the experimental group showed higher MMSE score (WMD = 2.60, 95% CI [2.16, 3.03], P < .001) and HDS score (WMD = 1.51, 95%CI [1.10, 1.92], P < .001). Due to few included studies, there were no statistically significance between experimental and control groups (WMD = -9.90, 95%CI [-26.09, 6.30], P = .231) regarding ADL score. In addition, there is no publication bias towards clinical effective rate and MMDE score. CONCLUSIONS: QFY only or combined with western medicine therapy can significantly improve cognitive ability compared with only western medicine therapy in dementia. However, multiple samples, RCTs of high quality are still needed to verify our conclusions.


Assuntos
Demência/tratamento farmacológico , Medicamentos de Ervas Chinesas/uso terapêutico , Atividades Cotidianas , Medicamentos de Ervas Chinesas/administração & dosagem , Medicamentos de Ervas Chinesas/efeitos adversos , Humanos , Testes de Estado Mental e Demência , Ensaios Clínicos Controlados Aleatórios como Assunto
7.
Inorg Chem ; 2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33570389

RESUMO

The development of oxygen evolution reaction (OER) catalysts with high activity and high stability through convenient and economical methods is greatly important for the promotion of hydrogen energy based on electrolysis technology. Herein, by using an unconventional high electrodeposition potential, novel petal-like clusters constructed by cross-linking ultrathin nickel hydroxide nanosheets were controllably synthesized on nickel foam (or copper foam or carbon cloth) and the effect of electrodeposition conditions on their OER performance was carefully explored. Due to the abundant catalytically active sites, promoting electron conduction/mass transmission from the specific micro-nano structure, as well as the ultrasmall thickness of ∼3.0 nm, the optimized α-Ni(OH)2/NF self-supporting electrode exhibits excellent electrocatalytic performance for OER, merely requiring low overpotentials of 192 and 240 mV to yield current densities of 10 and 100 mA cm-2 in 1.0 M KOH, respectively, which surpassed those of all of the reported nickel hydroxide/oxides and the benchmark RuO2. Moreover, α-Ni(OH)2/NF can drive the high-current density (500-1000 mA cm-2) OER at low overpotentials, meeting the requirements of potential industrial applications.

8.
Dalton Trans ; 50(4): 1246-1252, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33410827

RESUMO

By utilizing the hybrid-ligand conception, three novel dysprosium complexes Dy(2-py-4-pmc)(L)(H2O) (H2-py-4-pmc = 2-(2-pyridyl)pyrimidine-4-carboxylic acid; L = fumarate (fum, 1), succinate (suc, 2), or pimelate (pim, 3)) have been successfully synthesized. Structural analysis reveals that the dicarboxylate ligands connect 2-py-4-pmc--protected Dy3+ to form one-dimensional molecular ribbons. Magnetic measurements indicate that the three complexes exhibit typical slow magnetic relaxation under a zero dc field with effective reversal barriers Ueff of 180 K, 145 K and 137 K for 1-3, respectively, which is mainly attributed to the strong Ising anisotropy of dysprosium ions induced by the appropriate arrangement of carboxylate groups. Ab initio calculations demonstrate that the charge distribution around dysprosium ions and the magnetic interactions between them are key contributions to their different dynamic behaviour.

9.
Phytomedicine ; 82: 153444, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33421903

RESUMO

BACKGROUND: Despite granulocyte colony-stimulating factor (GCSF) is widely used in clinical, cancer chemotherapy induced neutropenia (CCIN) infection and infection-related mortality is high for lack of functionally mature neutrophils. Generating functional neutrophils is new therapeutic approaches to reduce CCIN-associated infection and mortality. Saikosaponin a (SSA) is one of the major bioactive components of Radix Bupleuri (RB) and exerts immunoregulatory effects. PURPOSE: The present study aims to investigate the efficacy and mechanism of SSA in CCIN therapy. METHODS: SSA was applied both in vitro and in vivo to assess the efficacy of CCIN therapy. The differentiation of neutrophils was measured by Nitroblue tetrazolium (NBT) reduction assay and Giemsa staining assay. The neutrophil differentiation related real-time transcription factors were detected by quantitative PCR (RT-qPCR) and Western Blot. Bacteria killing assay was used to assess the ability of fighting infection. Network pharmacology was employed to explore the mechanism network, and the predicted pathways were validated by Western Blot. RESULTS: We found that SSA contributed to generate functional mature neutrophils which capable of fighting infection both in vitro and in vivo. Network pharmacology prediction showed 55 pathways were predicted involved in SSA against CCIN. Further validation showed that CBL-ERK1/2 pathway was activated by SSA, which could upregulate PU.1 and CEBPß expression leading to neutrophil differentiation. CONCLUSIONS: Our findings suggest a natural regimen SSA regenerates microbicidal neutrophils to effectively reduce CCIN-associated infection via activating CBL-ERK1/2 pathway, providing a rationale for future therapeutic approaches.

10.
Food Funct ; 12(1): 362-372, 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33325949

RESUMO

Excessive alcohol drinking and a high-fat diet (HFD) promote steatohepatitis in the comorbidity of NAFLD and AFLD. Taxifolin (TAX) is a rich dihydroxyflavone compound found in onions, milk thistle and Douglas fir. We aimed to explore the intervention mechanism of TAX on chronic steatohepatitis induced by HFD feeding plus acute ethanol binge. We established an in vivo model by HFD feeding plus a single dose of ethanol binge, and established an in vitro model by oleic acid or palmitic acid on HepG2 cells to induce lipid accumulation. TAX regulated lipid synthesis by inhibiting the expression of SREBP1 and upregulating the PPARγ level. In addition, TAX inhibited the expression of P2X7R, IL-1ß, and caspase-1. Moreover, TAX reduced the expression of caspase-1 activation; thereby inhibiting the recruitment of macrophages and neutrophils. TAX also improved the inflammatory response caused by caspase-1 activation in steatotic hepatocytes. TAX exhibited an inhibitory effect on lipid accumulation and caspase-1-related pyroptosis. Collectively, TAX has therapeutic potential as an intervention of steatohepatitis induced by alcohol combined with HFD and for preventing non-alcoholic fatty liver degeneration targeting caspase-1-dependent pyroptosis.

11.
Viruses ; 12(12)2020 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-33297325

RESUMO

Geminiviruses possess single-stranded, circular DNA genomes and control the transcription of their late genes, including BV1 of many bipartite begomoviruses, through transcriptional activation by the early expressing AC2 protein. DNA binding by AC2 is not sequence-specific; hence, the specificity of AC2 activation is thought to be conferred by plant transcription factors (TFs) recruited by AC2 in infected cells. However, the exact TFs AC2 recruits are not known for most viruses. Here, we report a systematic examination of the BV1 promoter (PBV1) of the mungbean yellow mosaic virus (MYMV) for conserved promoter motifs. We found that MYMV PBV1 contains three abscisic acid (ABA)-responsive elements (ABREs) within its first 70 nucleotides. Deleting these ABREs, or mutating them all via site-directed mutagenesis, abolished the capacity of PBV1 to respond to AC2-mediated transcriptional activation. Furthermore, ABRE and other related ABA-responsive elements were prevalent in more than a dozen Old World begomoviruses we inspected. Together, these findings suggest that ABA-responsive TFs may be recruited by AC2 to BV1 promoters of these viruses to confer specificity to AC2 activation. These observations are expected to guide the search for the actual TF(s), furthering our understanding of the mechanisms of AC2 action.

12.
Sci Total Environ ; : 142925, 2020 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-33268246

RESUMO

Secondary particles account for a considerable proportion of fine particles (PM2.5) and reasonable reapportioning them to primary sources is critical for designing effective strategies for air quality improvement. This study developed a method which can reapportion secondary sources of PM2.5 solved by positive matrix factorization (PMF) to primary sources based on the isotopic signals of nitrate, ammonium and sulfate. Actual PM2.5 data in Beijing were used as a case study to assess the feasibility and capacity of this method. In the case, 20 chemical components were used to apportion PM2.5 sources and source contributions of nitrate were applied to reapportion secondary source to primary sources. The model performance was also estimated by radiocarbon measurement (14C) of organic (OC) and elemental (EC) carbons of eight samples. The PMF apportioned seven sources: the secondary source (36.1%), vehicle exhausts (18.7%), industrial sources (13.6%), biomass burning (11.4%), coal combustion (8.10%), construction dust (7.93%) and fuel oil combustion (4.24%). After the reapportionment of the secondary source, vehicle exhausts (28.7%) contributed the most to PM2.5, followed by biomass burning (25.1%) and industrial sources (18.9%). Fossil oil combustion and coal combustion increased to 8.00% and 11.4%, respectively, and construction dust contributed the least. The average gap between contributions of identified sources to OC and EC and the 14C measurements decreased 2.5 ± 1.2% after the reapportionment than 13.2 ± 10.8%, indicating the good performance of the developed method.

14.
Artigo em Inglês | MEDLINE | ID: mdl-33175568

RESUMO

BACKGROUND: Gastric cancer (GC) is one of the most common and lethal cancers and the prognosis of GC patients remains very poor. Cancer-associated fibroblasts (CAFs) largely facilitate the progression of GC but the underlying molecular mechanisms remain elusive despite numerous studies. Here, we investigated the role of CLIC1 in CAF activation and GC. METHODS: qRT-PCR and western blot were performed to determine expression levels of cytokines, transcription factors and related proteins such as CAF markers. MTT assay was used to examine the proliferation of GC cells while transwell assay and tumorsphere formation assay were done to measure the migration, invasion and stemness of GC cells. Conditioned medium model was used to examine the intercellular communication between CAFs and GC cells. RESULTS: Overexpression of CLIC1 in fibroblasts induced CAF activation and enhanced cell proliferation and migration. Also, CLIC1 up-regulated integrins/NF-κB signaling in CAFs. CLIC1-overexpressed fibroblasts promoted proliferation and migration of GC cells and up-regulated cancer stem cell markers and promoted EMT program of GC cells. IL-6 and IL-8 neutralizing antibodies inhibit the pro-tumor effects of CLIC1-overexpressing fibroblasts on GC cells. Further, knockdown CLIC1 in GC cells suppressed activation of CAF. CONCLUSIONS: CLIC1 overexpression activates CAF via up-regulating integrins/NF-κB signaling and activated CAF releases IL-6 and IL-8 to promote multiple malignant phenotypes of GC cells. These results implicate an essential role of CLIC1 in CAF activation and GC progression, which suggests that CLIC1 could serve as a potential target for GC therapy.

15.
Medicine (Baltimore) ; 99(45): e21379, 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-33157907

RESUMO

BACKGROUND: This study will systematically explore the effects of Xingnaojing (XNJ) on serum high-sensitivity C-reactive protein (hs-CRP) and neuron-specific enolase (NSE) in patients with acute cerebral hemorrhage (ACH). METHODS: We will comprehensively search the following electronic databases (MEDLINE, EMBASE, Cochrane Library, Allied and Complementary Medicine Database, and China National Knowledge Infrastructure) from inception to the March 1, 2020. There are no limitations related to the language and publication status. Two authors will independently perform all citation identification, information extraction, and study quality. All potential conflicts will be solved through discussion with the help of a third author. RevMan 5.3 software will be used for data synthesis and statistical analysis. RESULTS: This study will summarize the present evidence to investigate the effects of XNJ on serum hs-CRP and NSE in patients with ACH. CONCLUSION: This study may provide an impressive understanding of perspective from scientific basis for effects of XNJ on serum hs-CRP and NSE in patients with ACH. STUDY REGISTRATION: PROSPERO CRD42020171648.


Assuntos
Proteína C-Reativa/metabolismo , Hemorragia Cerebral/tratamento farmacológico , Medicamentos de Ervas Chinesas/farmacologia , Fosfopiruvato Hidratase/metabolismo , Projetos de Pesquisa , Humanos , Metanálise como Assunto , Revisões Sistemáticas como Assunto
16.
Nat Neurosci ; 23(12): 1589-1596, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33139942

RESUMO

Information processing in the brain depends on specialized organization of neurotransmitter receptors and scaffolding proteins within the postsynaptic density. However, how these molecules are organized in situ remains largely unknown. In this study, template-free classification of oversampled sub-tomograms was used to analyze cryo-electron tomograms of hippocampal synapses. We identified type-A GABA receptors (GABAARs) in inhibitory synapses and determined their in situ structure at 19-Å resolution. These receptors are organized hierarchically: from GABAAR super-complexes with a preferred inter-receptor distance of 11 nm but variable relative angles, through semi-ordered, two-dimensional receptor networks with reduced Voronoi entropy, to mesophasic assembly with a sharp phase boundary. These assemblies likely form via interactions among postsynaptic scaffolding proteins and receptors and align with putative presynaptic vesicle release sites. Such mesophasic self-organization might allow synapses to achieve a 'Goldilocks' state, striking a balance between stability and flexibility and enabling plasticity in information processing.

17.
Neuron ; 2020 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-33147442

RESUMO

SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) complex, composed of synaptobrevin, syntaxin, and SNAP25, forms the essential fusion machinery for neurotransmitter release. Recent studies have reported several mutations in the gene encoding SNAP25 as a causative factor for developmental and epileptic encephalopathies of infancy and childhood with diverse clinical manifestations. However, it remains unclear how SNAP25 mutations give rise to these disorders. Here, we show that although structurally clustered mutations in SNAP25 give rise to related synaptic transmission phenotypes, specific alterations in spontaneous neurotransmitter release are a key factor to account for disease heterogeneity. Importantly, we identified a single mutation that augments spontaneous release without altering evoked release, suggesting that aberrant spontaneous release is sufficient to cause disease in humans.

18.
Chem Commun (Camb) ; 56(78): 11645-11648, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-33000783

RESUMO

Two-dimensional (2D) multilayered graphitic carbon nanosheets are prepared via a facile, green, and mild method of one-pot hydrothermal carbonization at a temperature below 300 °C. Copper with a 2D structure is formed in situ and serves as both a template and catalyst. The obtained multilayered carbon nanosheets exhibit well-defined shapes and a radius-to-thickness ratio as high as 104, with monolayer thickness as small as 2.86 nm.

19.
Inflammopharmacology ; 28(6): 1481-1493, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33006110

RESUMO

Gout, the most prevalent inflammatory arthritis worldwide, released interleukin-1ß (IL-1ß) and Cathepsin B inflammatory mediators that constitute the hallmark of the disease. Herein we aimed to investigate whether procyanidin B2 (PCB2), a natural dietary compound, can suppress MSU crystals-stimulated gouty inflammation. Treated with lipopolysaccharide (LPS) plus MSU, both mouse peritoneal macrophages (MPM) and mouse bone marrow-derived macrophages (BMDM) released a large amount of mature IL-1ß compared to those treated with MSU or LPS alone, while IL-1ß release was blocked by TLR4 and its downstream effector inhibitors. In two mouse models of gout, oral administration of PCB2 suppressed MSU crystals-induced increasing expression of IL-1ß, Cathepsin B and NLRP3 in the air pouch skin and paws, accompanied with the downregulation prostaglandin E2 (PGE2) in pouch exudates. Inflammatory immune cell infiltration including macrophages and neutrophils were significantly blocked by PCB2 in air pouch skin and paws of mice gout groups. PCB2 also suppressed the release of IL-1ß and Cathepsin B induced by MSU plus LPS in MPM. Our results suggest that the inhibitory effects of PCB2 on NLRP3 inflammasome may alleviate inflammatory response in gout, and this might be a promising anti-inflammatory mechanism of PCB2 against the inflammation in gout.

20.
ACS Nano ; 14(10): 14134-14145, 2020 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-33044056

RESUMO

Flexible and lightweight high-performance electromagnetic interference shielding materials with minimal thickness, excellent mechanical properties, and outstanding reliability are highly desired in the field of fifth-generation (5G) communication, yet remain extremely challenging to manufacture. Herein, we prepared an ultrathin densified carbon nanotube (CNT) film with superior mechanical properties and ultrahigh shielding effectiveness. Upon complete removal of impurities in pristine CNT film, charge separation in individual CNTs induced by polar molecules leads to strong CNT-CNT attraction and film densification, which significantly improve the electrical conductivity, shielding performance, and mechanical strength. The tensile strength is up to 822 ± 21 MPa, meanwhile the electrical conductivity is as high as 902,712 S/m, and the density is only 1.39 g cm-3. Notably, the shielding effectiveness is over 51 dB with a thickness of merely 1.85 µm in the broad frequency range of 4-18 GHz, and it reaches to ∼82 dB at 6.36 µm and ∼101 dB at 14.7 µm, respectively. Further, such CNT film exhibits excellent reliability after an extended period in strong acid/alkali, high temperature, and high humidity. It demonstrates the best overall performance among representative shielding materials by far, representing a critical breakthrough in the preparation of shielding film toward applications in wearable electronics and 5G communication.

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