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Purpose: This study investigated the influence of plasma proprotein convertase subtilisin/kexin 9 (PCSK9) levels on the degree of atherosclerosis and major adverse cardiovascular and cerebrovascular events (MACCE) in older adults with non-alcoholic fatty liver disease. Methods: The degree of atherosclerosis severity was assessed by the standard Gensini score quartile method. According to the degree of atherosclerosis, patients were divided into mild (0-24 points; n=84), moderate (25-53 points; n=86), and severe groups (≥54 points; n=84) and then categorized as MACCE (n=30) or non-MACCE (n=224) according to 6-month follow-up data. The patients' age, sex, smoking history, medical history, and early morning fasting venous blood, for measuring biochemical indexes, were collected. Clinical data were compared between groups and the relationship between Gensini scores and PCSK9 was evaluated. Results: Compared with the mild group, the moderate and severe groups had higher high-sensitivity C-reactive protein(hs-CRP), PCSK9, triglycerides(TG), low-density lipoprotein cholesterol (LDL-C), and lipoprotein(a)[Lp(a)] levels and lower high-density lipoprotein cholesterol(HDL-C) levels (all P<0.05). Moreover, PCSK9 positively correlated with Gensini scores (r=0.657, P<0.01). The MACCE and non-MACCE groups had significantly different ages, statin use, Gensini scores, PCSK9, and LDL-C (all P<0.05). Multi-factorial Cox risk regression analysis showed the Gensini score (HR=1.018, 95% CI: 1.006~1.029) and PCSK9 (HR=1.147, 95% CI: 1.038~1.287) were independent risk factors for MACCE. Conclusion: The Gensini score and PCSK9 levels can be used as predictive indicators for the degree of illness and occurrence of MACCE in older NAFLD patients.
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Mechanoluminescence materials that emit light under mechanical stimulation have attracted widespread attention in sensing, anticounterfeiting, and imaging applications. In this study, a series of Sr1-xBixZnSO (0.001 ≤ x ≤ 0.1) samples was synthesized by the method of high temperature solid-state reaction. It is worth noting that the distortion degree of the SrO3S3 octahedron was increased with increasing Bi3+ concentration, and the color manipulated Sr1-xBixZnSO which can emit different photoluminescence (blue to dark blue and finally red) and mechanoluminescence (orange to red) colors is obtained. Moreover, the deep traps can stably store and provide electronic supplements in shallow traps released under mechanical stimulation. Therefore, devices made of SrZnSO:Bi3+ phosphor and polydimethylsiloxane (PDMS) can be used as thermo-mechano-opto three-mode anticounterfeiting. The ML intensity is linear to the external load and can be utilized for stress sensing or imaging.
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A series of Bi3+ and Mn2+ co-doped CaZnOS phosphors with a tunable emission color have been synthesized by a high temperature solid-state reaction method. Their crystal structure, spectroscopic properties, energy transfer and thermal quenching have been investigated systematically. An intense blue-green emission band at 485 nm and a red emission band at 616 nm were observed at an excitation wavelength of 375 nm, owing to the 3P1,0â1S0 transition of Bi3+ and the 4T1(4G) â6A1(6S) transition of Mn2+, respectively. The tunable color from blue-green, white light to red light can be obtained by varying the Mn2+ ion concentration from 0.005 to 0.015 in CaZnOS:Bi3+. The decay time decreased from 642 to 273 ns with the Mn2+ ion concentration x increasing from 0.005 to 0.015, and the energy transfer efficiency ηT can reach up to 65% in the CaZnOS:Bi3+,0.015Mn2+ phosphor. As the temperature increases from 300 to 420 K, the emission intensity is maintained at 67%, and the activation energy Ea is estimated to be 0.28 eV. An LED fabricated using CaZnOS:Bi3+,0.01Mn2+ exhibited the chromaticity coordinates and corrected color temperature (CCT) of (0.338, 0.364) and 4655 K, respectively. These results validate the promising applications of the CaZnOS:Bi3+,Mn2+ phosphor in UV white LEDs.
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To meet the increasing requirements of minimizing circuits, the development of novel device architectures that use ultra-thin two-dimensional materials is encouraged. Here, we demonstrate a non-volatile black phosphorus (BP) PNP junction in a BP/h-BN/graphene heterostructure in which BP acts as a transport channel layer, hexagonal boron nitride (h-BN) serves as a tunnel barrier layer and graphene is the charge-trapping layer. The device architecture is designed such that only the middle part of the BP is aligned over the graphene flake, enabling the flexible tuning of the charge carriers in the BP over the graphene charge-trapping layer. Thus, the device exhibits the ability to work in two different operating modes (PNP and PP+P). Each operating mode can be retained well and demonstrates non-volatile behavior, and each can be programmed by using the control-gate.
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For specific application to an uncooled infrared detector, VO2 thin films should have a series of characteristics including purposefully chosen polymorphs, accurate stoichiometry, phase stabilization, a high temperature-coefficient of resistance (TCR), and suitable square-resistance. This work reports controllable preparation of high-performance VO2 films via post annealing of a sandwich-structured V2O5/metal (V, W)/V2O5 multilayer precursor, which was deposited by RF magnetron sputtering. This sandwich structure can dynamically regulate oxygen contents and doping element levels in the films, enabling us to achieve accurate regulation of stoichiometry and polymorphs. The precursor films undergo a B to M phase transition depending on the quantity of the metal layers. At the thickness of the metal layer below a limitation, the resulting film after heat treatment was VO2 (B), and above the limitation, the product was VO2 (M). The optical modulation of the VO2 (M) in the near-infrared region can be tuned from 1.2 to 39.8% (ΔT2000 nm). TCR values can range from -1.89 to -4.29%/K and the square-resistances at room temperature (R0) from 69.68 to 12.63 kΩ. The simplicity in phase regulation of the present method and the superior optical and electrical properties of the films may allow its wide applications in thermo-opto-electro sensing devices.
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We report a new rapid household microwave method to successfully grow graphene on h-BN flakes without using any catalysts. We obtained a novel uniform multilevel matrix of vertical graphene sheets on h-BN flakes. The unique structure possessed outstanding electron conductivity and thermal properties (29.1 W m(-1) K(-1)).
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Modification of rutile titanium dioxide (TiO2) for hydrogen generation and water cleaning is a grand challenge due to the chemical inertness of rutile, while such inertness is a desired merit for its stability in photoelectrochemical applications. Herein, we report an innovative two-step method to prepare a core-shell nanostructured S-doped rutile TiO2 (R'-TiO2-S). This modified black rutile TiO2 sample exhibits remarkably enhanced absorption in visible and near-infrared regions and efficient charge separation and transport. As a result, the unique sulfide surface (TiO(2-x):S) boosts the photocatalytic water cleaning and water splitting with a steady solar hydrogen production rate of 0.258 mmol h(-1) g(-1). The black titania is also an excellent photoelectrochemical electrode exhibiting a high solar-to-hydrogen conversion efficiency of 1.67%. The sulfided surface shell is proved to be an effective strategy for enhancing solar light absorption and photoelectric conversion.
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The composite substrate of Co and Cu was proposed to grow homogenous high quality wafer-size graphene films by an atmosphere pressure CVD method. The composite substrate consists of a moderate-carbon-solubility metal top (Co coating) as a C-dissolving layer and a low-carbon-solubility metal base (Cu foil) as a C-rejecting layer. During the CVD process, the interdiffusion of Co and Cu atoms occurs in the composite. With the dynamic control on Co and Cu alloying process to affect the carbon solubility, active carbon atoms captured by the Co layer were segregated to form spontaneously a high-quality graphene film on the top of Cu-Co substrate. The tunable layer-number of the graphene films can be precisely controlled by adjusting the thickness of the Co layer. High quality single-layered graphene films with a 98% yield were prepared on an 80 nm-Co-coated Cu foil and insensitive to growth temperature and time. More importantly, this type of composite substrate has also been developed to grow AB-stacked bilayers and three-layer graphene with 99% surface coverage and absence of defects. The approach is opening up a new avenue for high-quality graphene production with precise layer control through composite substrate design.
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Nanostrcutured particles and polycrystalline thin films of Sn-doped chalcopyrite are synthesized by newly-developed methods. Surprisingly, Sn doping introduces a narrow partially filled intermediate band (IB) located ~1.7 eV (CuGaS(2)) and ~0.8 eV (CuInS(2)) above the valance band maximum in the forbidden band gap. Diffuse reflection spectra and photoluminescence spectra reveal extra absorption and emission spectra induced by the IBs, which are further supported by first-principle calculations. Wide spectrum solar response greatly enhances photocatalysis, photovoltaics, and photo-induced hydrogen production due to the intermediate band.
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A novel architecture of graphene paper is proposed to consist of "1D metallic nanowires/defect-free graphene sheets". Highly conductive and flexible papers of 1D silver nanowires (Ag NWs) and chemical vapor deposition (CVD) graphene sheets as an example were fabricated by a simple filtration method. CVD graphene paper possesses much higher electrical conductivity of 1097 S/cm, compared with other reported carbon-related papers (graphene, carbon nanotube, etc.). With the addition of Ag NWs to form Ag NWs/graphene paper, the electrical conductivity is further improved up to 3189 S/cm, even higher than â¼2000 S/cm of bulk graphite. Ag NWs/graphene papers have very good flexibility with the only <5% loss of electrical conductivity over 500 times mechanical bending. Highly conductive composite papers have potential in high-performance, flexible energy conversion and storage devices.
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Nanoparticle-assembled vanadium dioxide (VO2) films have been easily prepared with the assistance of cetyltrimethylammonium vanadate (CTAV) precursor which exhibits self-assembly properties. The obtained VO2 film has a micro/nano hierarchical porous structure, so its visible-light transmittance is significantly improved (â¼25% increased compared to continuous film). The VO2 particle density as well as the film porosity can be facilely controlled by adjusting experimental parameters such as dip-coating speed. Accordingly, film optical properties can also be tuned to a large extent, in particular the visible transmittance (Tvis) and near-infrared switching efficiency (ΔTnir). These VO2 nanoparticle-assembled films prepared by this novel method provide a useful model to research the balance between Tvis and ΔTnir.
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Low-temperature aluminum (Al) reduction is first introduced to reduce graphene oxide (GO) at 100-200 °C in a two-zone furnace. The melted Al metal exhibits an excellent deoxygen ability to produce well-crystallized reduced graphene oxide (RGO) papers with a low O/C ratio of 0.058 (Al-RGO), compared with 0.201 in the thermally reduced one (T-RGO). The Al-RGO papers possess outstanding mechanical flexibility and extremely high electrical conductivities (sheet resistance R(s) ~ 1.75 Ω/sq), compared with 20.12 Ω/sq of T-RGO. More interestingly, very nice hydrophobic nature (90.5°) was observed, significantly superior to the reported chemically or thermally reduced papers. These enhanced properties are attributed to the low oxygen content in the RGO papers. During the aluminum reduction, highly active H atoms from H(2)O reacted with melted Al promise an efficient oxygen removal. This method was also applicable to reduce graphene oxide foams, which were used in the GO/SA (stearic acid) composite as a highly thermally conductive reservoir to hold the phase change material for thermal energy storage. The Al-reduced RGO/SnS(2) composites were further used in an anode material of lithium ion batteries possessing a higher specific capacity. Overall, low-temperature Al reduction is an effective method to prepare highly conductive RGO papers and related composites for flexible energy conversion and storage device applications.
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Alumínio/química , Fontes de Energia Elétrica , Grafite/química , Lítio/química , Nanopartículas Metálicas/química , Condutividade Elétrica , Transferência de Energia , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais , Nanopartículas Metálicas/ultraestrutura , Oxirredução , Óxidos/química , Temperatura , MolhabilidadeRESUMO
A one-step high-temperature hydrated-sulfate assisted solvothermal method has been developed to synthesize TiO(2)/sulfide nanocomposite spheres. Different hybrid spheres of TiO(2)/CdS, TiO(2)/Cu(2)S, TiO(2)/FeS, TiO(2)/Co(9)S(8), and TiO(2)/ZnS were readily prepared by exploiting different hydrated sulfate. The hydrated sulfate has been proved to play multifunctional roles during the synthetic process, such as spherical template, water supplier, and composition controller. Nanocrystal CdS can be reduced from CdSO(4) at a high solvothermal temperature of 350 °C, and the TiO(2)/CdS nanocomposite spheres prepared by this method exhibit superior visible-light-driven photocatalytic efficiency because of its effective heterointerface and high crystallinity.
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Dominantly (211)-oriented In(2)O(3):Sn (ITO) transparent conducting oxide (TCO) films were first fabricated at high sputtering power in the weak reducing ambient with superior electrical and optical properties. The dependence of ITO film orientation on growth condition was systematically investigated, and the formation mechanism was studied by surface energy calculation and band structure simulation. The unique properties of the (211)-oriented films should be ascribed to the richest In-terminated surface of the (211) plane, which is tightly correlated with the comparably highest surface energy and highest conduction band surface comparing with the other two typical planes of (222) and (400). The as-prepared (211)-oriented ITO films with the In-rich ending atoms on the surface are of great significance for the transparent electrode applications.
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Amino acids, as a particularly important type of biomolecules, have been used as multifunctional templates to intelligently construct mesoporous TiO(2) hollow structures through a simple solvothermal reaction. The structure-directing behaviors of various amino acids were systematically investigated, and it was found that these biomolecules possess the general capability to assist mesoporous TiO(2) hollow-sphere formation. At the same time, the nanostructures of the obtained TiO(2) are highly dependent on the isoelectric points (pI) of amino acids. Their molecular-structure variations can lead to pI differences and significantly influence the final TiO(2) morphologies. Higher-pI amino acids (e.g., L-lysine and L-arginine) have better structure-directing abilities to generate nanosheet-assembled hollow spheres and yolk/shell structures. The specific morphologies and mesopore size of these novel hollow structures can also be tuned by adjusting the titanium precursor concentration. Heat treatment in air and vacuum was further conducted to transform the as-prepared structures to porous nanoparticle-assembled hollow TiO(2) and TiO(2)/carbon nanocomposites, which may be potentially applied in the fields of photocatalysts, dye-sensitized solar cells, and Li batteries. This study provides some enlightenment on the design of novel templates by taking advantage of biomolecules.
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Aminoácidos/química , Arginina/química , Corantes/química , Lisina/química , Nanoestruturas/química , Titânio/química , Catálise , Modelos Moleculares , Estrutura Molecular , Fotoquímica , Porosidade , Energia Solar , TemperaturaRESUMO
Resonant Raman scattering (RRS) spectra of individual carbon nanotubes on a SiO2 substrate have been investigated first in the temperature range of 100-600 K (Phys. Rev. B 2002, 66, 115411). It was revealed by the intensity abnormality of the radial breathing mode (RBM) that the carbon nanotubes have a temperature-dependent density of electronic states. This means that the previously reported temperature coefficients of RBM of carbon nanotubes are smaller than their "real" ones for the bulk samples of single- or double-walled carbon nanotubes. Comparatively, the G line of individual nanotubes shows no observable difference relative to the bulk samples.