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1.
Plant Dis ; 107(10): 3007-3013, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36856651

RESUMO

Grape downy mildew caused by Plasmopara viticola is one of the most devastating diseases of grapevine worldwide. Quinone outside inhibitor (QoI) fungicides are commonly used for the control of the pathogen in grape fields across China. However, their recurrent use could lead to the emergence of resistance against these compounds. Based on the most common mutation in resistant isolates, a glycine to alanine substitution at amino acid position 143 (G143A) in the cytochrome b protein, a TaqMan-MGB PCR was developed for the rapid detection of resistance to the QoI fungicide azoxystrobin in P. viticola. Specificity and sensitivity of this method showed it could specifically detect the point mutations linked with QoI resistance in P. viticola, and the detection limit was 0.2 pg. It could also quantify the resistance allele even in isolate mixtures containing as little as 5% QoI-resistant P. viticola strains. With this method, a large P. viticola population (n = 2,373) was screened, and QoI-resistant isolates were identified for the first time in China. The average frequencies of the resistant genotype from eight major-grapevine regions were up to 66%. Taken together, the results not only provide a novel tool for the rapid distinction and quantification of the QoI-resistant allele in P. viticola but also provide important references for fungicide selection and application, which will facilitate resistance management of grape downy mildew and improve grape production systems in Chinese vineyards.


Assuntos
Fungicidas Industriais , Oomicetos , Fungicidas Industriais/farmacologia , Oomicetos/efeitos dos fármacos , Oomicetos/genética , Reação em Cadeia da Polimerase , Quinonas , Resistência a Medicamentos
2.
Plant Dis ; 104(9): 2338-2345, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32697657

RESUMO

Grape production is increasing globally and so are problems with downy mildew, one of the main constraints in grape production. Downy mildew on grape is caused by Plasmopara viticola, an obligate biotrophic pathogen belonging to the oomycetes. Control of the disease is usually performed by fungicide applications, of which carboxylic acid amide (CAA) fungicides represent one of the most widely used groups of fungicides. Our previous research showed that the extensive application of CAA fungicides can result in fungicide resistance and in China, CAA-resistant isolates of P. viticola were collected from the field in 2014. To monitor the distribution and spread of CAA fungicide resistance, we developed a TaqMan-minor groove binder (MGB) real-time PCR-based method designed on a functional mutation in the PvCesA3 gene that allows efficient identification of CAA fungicide resistant and sensitive genotypes. The assay was validated on 50 isolates using Sanger sequencing and fungicide bioassays and exploited in a comprehensive survey comprising 2,227 single-sporangiophore isolates from eight major grapevine regions in China. We demonstrate that CAA fungicide resistance in P. viticola is widespread in China. On average, 53.3% of the isolates were found to be resistant, but marked differences were found between locations with percentages of resistant isolates varying from 0.3 to 96.6%. Furthermore, the frequency of CAA-resistant isolates was found to be significantly correlated with the exposure to CAA fungicides (P < 0.05). We further discussed the possibilities to apply the TaqMan-MGB real-time PCR assay to assess the frequency of fungicide-resistant P. viticola isolates in each region or vineyard, which would facilitate the correct choice of fungicide for grape downy mildew and resistance management strategies.


Assuntos
Farmacorresistência Fúngica , Oomicetos/genética , Amidas , Ácidos Carboxílicos , China , Reação em Cadeia da Polimerase em Tempo Real
3.
J Chem Phys ; 151(21): 211101, 2019 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-31822097

RESUMO

Cesium lead bromide (CsPbBr3) perovskite has attracted great attention recently for its potentials for next-generation green-color lasing devices owing to the relatively high structural stability and the high emission efficiency among the perovskite family. Herein, we explore the origins of cavity modes in CsPbBr3 microplatelets (MPs) lasers by using angle-resolved microphotoluminescence Fourier imaging technique, which is still controversial so far. In-plane Fabry-Pérot (F-P) mode lasing transition to whispering-gallery-mode (WGM) lasing is verified at room temperature, which mostly occurs in large MPs with edge length (L) over 13 µm. The F-P lasing is suppressed upon decreasing L or increasing excitation density, and the WGM lasing is predominant for all MPs at high excitation density. Furthermore, the parity and symmetry of in-plane F-P modes are classified. These results advance the fundamental understanding of lasing modes in planar microcavities as well as their applications in on-chip interconnection and quantum optics.


Assuntos
Compostos de Cálcio/química , Lasers , Óxidos/química , Titânio/química , Óptica e Fotônica , Tamanho da Partícula , Teoria Quântica , Propriedades de Superfície
4.
Arch Gynecol Obstet ; 299(1): 247-258, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30523439

RESUMO

PURPOSE: To systematically evaluate the effect of maternal and embryonic factors on in vitro fertilization and embryo transfer (IVF-ET) outcomes among Chinese patients after using hyaluronan-enriched transfer medium (HETM). METHODS: This retrospective study included 637 frozen-thawed ET cycles. Patients were divided into subgroups based on their maternal or embryonic status or treatment procedures. The implantation, clinical pregnancy, delivery, and abortion rates were compared between the HETM and control groups. In addition, the implantation and clinical pregnancy rates were used to analyze the reciprocal effect of HETM and Preimplantation genetic screening (PGS) assessment. RESULTS: Maternal risk factors, especially maternal aging and a low number of retrieved oocytes, have a significant adverse impact on the efficacy of HETM usage. Endometrial preparation with artificial and natural cycles but not stimulated cycles showed a satisfying outcome after IVF-ET treatment. Compared with cleavage embryos, blastocyst stage embryo transfer showed more prominent improvement when using HETM. Prolonged pre-equilibration treatment with HETM notably compromised the IVF-ET outcome. PGS-based preselection could further facilitate the HETM-induced beneficial effect on IVF-ET outcomes. The body weight, length, and sex ratio of the neonate did not significantly differ between the HETM and control groups. CONCLUSION: Both the maternal and embryonic status or treatment procedures affected the IVF-ET outcomes after using HETM. HETM had a beneficial effect on advantaged IVF cycles but did not improve the outcomes of disadvantaged IVF cycles. Endometrial preparation with stimulated cycles is not recommended when using HETM. Prolonged pre-equilibration treatment must be avoided.


Assuntos
Criopreservação/estatística & dados numéricos , Meios de Cultura , Transferência Embrionária/estatística & dados numéricos , Fertilização in vitro/estatística & dados numéricos , Ácido Hialurônico , Resultado da Gravidez , Adulto , Implantação do Embrião , Transferência Embrionária/métodos , Feminino , Fertilização in vitro/métodos , Humanos , Recém-Nascido , Idade Materna , Recuperação de Oócitos , Gravidez , Taxa de Gravidez , Diagnóstico Pré-Implantação , Estudos Retrospectivos
5.
J Nanosci Nanotechnol ; 16(4): 3622-7, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27451677

RESUMO

Three-dimensional stacking of ZnO nanorods on conducting aluminum-doped ZnO (AZO) glass were studied as efficient photoanodes of dye sensitized solar cells (DSSCs). By changing hydrothermal growth time and cycle times, the thickness of ZnO nanorods stacking films varied from 30 µm to 64 µm, and its influence on the energetic conversion efficiency of the DSSCs based on the stacking films photoanodes was investigated. The loading density of N719 on the surface of ZnO nanorods was studied to increase the efficiency of the cells. Annealing experiments showed that the AZO substrates remained good conductors until heated above 350 °C. A photoelectric conversion efficiency as high as ~2.0% together with ISC of ~9.5 mA/cm2, VOC of ~0.5 V and FF of ~41.4% was achieved for the DSSC using 50 µm-thick film stacking by ZnO nanorods as photoanode and N719 as sensitizer under illumination of AM1.5G solar light (power density of 100 mW/cm2). A charge separation and transfer mechanism was proposed for the ZnO nanorods stacking electrode-based DSSCs.


Assuntos
Corantes/química , Fontes de Energia Elétrica , Eletrodos , Nanotubos/química , Energia Solar , Óxido de Zinco/química , Corantes/efeitos da radiação , Cristalização/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais , Membranas Artificiais , Nanotubos/ultraestrutura , Óxido de Zinco/efeitos da radiação
6.
Nanoscale ; 15(37): 15344-15351, 2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37698246

RESUMO

2D-material-based van der Waals heterostructures (vdWhs) have shown great potential in next-generation multi-functional microelectronic devices. Thanks to their sharp interface and ultrathin thickness, 2D p-n junctions with high rectification properties have been established by combining p-type monochalcogenides with n-type transition metal dichalcogenides. However, the anisotropic rectification together with the charge transfer and gate effect has not been clarified. Herein, the electrical anisotropy of p-SnS/n-MoS2 diodes was studied. Optimum ideality factors within 1.08-1.18 have been achieved for the diode with 6.6 nm thick SnS on monolayer MoS2, and a high rectification ratio of 3.1 × 104 with strong in-plane anisotropy is observed along the zigzag direction of SnS. A strong gate effect on the anisotropic series resistance has been verified and an effective tuning over the transport length of the SnS channel can be established through adjustment of the current orientation and gate voltage. A thickness-dependent minority carrier transport mechanism has also been demonstrated for the reverse drain current, and Fowler-Nordheim tunneling and direct tunneling are proposed for the increase of the reverse current of the thicker and thinner diodes, respectively. This work will provide another strategy for high-performance diodes based on vdWhs via the control of the current orientation and the gate effect.

7.
ACS Nano ; 17(22): 23160-23168, 2023 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-37926969

RESUMO

The discovery of ferromagnetism in two-dimensional (2D) van der Waals crystals has generated widespread interest. The seeking of robust 2D ferromagnets with high Curie temperature (Tc) is vitally important for next-generation spintronic devices. However, owing to the enhanced spin fluctuation and weak exchange interaction upon the reduced dimensionalities, the exploring of robust 2D ferromagnets with Tc > 300 K is highly demanded but remains challenging. In this work, we fabricated air-stable 2D Cr5Te8/CrTe2 vertical heterojunctions with Tc above 400 K by the chemical vapor deposition method. Transmission electron microscopy demonstrates a high-quality-crystalline epitaxial structure between tri-Cr5Te8 and 1T-CrTe2 with striped moiré patterns and a superior ambient stability over six months. A built-in dual-axis strain together with strong interfacial coupling cooperatively leads to a record-high Tc for the CrxTey family. A temperature-dependent spin-flip process induces the easy axis of magnetization to rotate from the out-of-plane to the in-plane direction, indicating a phase-dependent proximity coupling effect, rationally interpreted by first-principles calculations of the magnetic anisotropy of a tri-Cr5Te8 and 1T-CrTe2 monolayer. Our results provide a material realization of effectively enhancing the transition temperature of 2D ferromagnetism and manipulating the spin-flip of the easy axis, which will facilitate future spintronic applications.

8.
ACS Omega ; 8(11): 10545-10554, 2023 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-36969393

RESUMO

Benchtop nuclear magnetic resonance (NMR) spectroscopy has enabled the monitoring and optimization of chemical transformations while simultaneously providing kinetic, mechanistic, and structural insight into reaction pathways with quantitative precision. Moreover, benchtop NMR proton lock capabilities further allow for rapid and convenient monitoring of various organic reactions in real time, as the use of deuterated solvents is not required. The complementary role of 19F NMR-based kinetic monitoring in the fluorination of bioactive compounds has many benefits in the drug discovery process since fluorinated motifs additionally improve drug pharmacology. In this study, 19F NMR spectroscopy was utilized to monitor the synthesis of novel trifluorinated analogs of monastrol, a small molecule dihydropyrimidinone kinesin-Eg5 inhibitor, and to probe the mechanism of the Biginelli cyclocondensation, a multicomponent reaction used to synthesize dihydropyrimidinone and tetrahydropyrimidinones through a Bronsted- or Lewis-acid catalyzed cyclocondensation between ethyl acetoacetate, thiourea, and an aryl aldehyde. In the present study, a trifluorinated ketoester serves a dual purpose as being the source of the trifluoromethyl group in our fluorinated dihydropyrimidinones and as a spectroscopic handle for real-time reaction monitoring and tracking of reactive intermediates by 19F NMR. Further, upon extending this workflow to a diverse array of 3- and 4-substituted aryl aldehydes, we were able to derive Hammett linear free energy relationships (LFER) to determine stereoelectronic effects of para- and meta-substituted aryl aldehydes to corresponding reaction rates and mechanistic routes. In addition, we used density functional theory (DFT) calculations to corroborate our experimental results through the thermodynamic values of key intermediates in each mechanism. Finally, these studies culminate in the synthesis of a novel trifluorinated analog of monastrol and its subsequent biological evaluation in vitro. More broadly, we show an application of benchtop 19F NMR spectroscopy as an analytical tool in the real-time investigation of a mechanistically and chemically complex multicomponent reaction mixture.

9.
Front Public Health ; 10: 1022199, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36304247

RESUMO

The association between exposure to ambient fine particulate matter with an aerodynamic diameter of ≤ 2.5 µm (PM2.5) and short- and medium-term lung function recovery (LFR) in patients undergoing lobectomy remains uncertain. This study investigated the associations between PM2.5 concentrations and LFR in adult patients (n = 526) who underwent video-assisted thoracoscopic (VATS) lobectomy in Guangzhou, China between January 2018 and June 2021. All patients underwent at least two spirometry tests. Environmental PM2.5 concentrations in the same period were collected from the nearest monitoring station. A multiple linear regression (MLR) model was employed to investigate the associations between changes in PM2.5 concentrations and LFR in patients who underwent lobectomy after adjusting for potential confounders. We assessed short- and medium-term LFR in patients who underwent lobectomy. The three- and 6-month average PM2.5 concentrations in each patient's residential area were divided into regional mild pollution (PM2.5 <25 µg/m3), moderate pollution (25 µg/m3 ≤ PM2.5 <35 µg/m3), and severe pollution (35 µg/m3 ≤ PM2.5) periods. The MLR model confirmed that PM2.5 was an independent risk factor affecting short-term forced lung capacity (FVC), forced expiratory volume in 1 s (FEV1), and maximum expiratory flow at 50% vital capacity (MEF50) recovery (adjusted P = 0.041, 0.014, 0.016, respectively). The MLR model confirmed that PM2.5 was an independent risk factor affecting medium-term MEF50 recovery (adjusted P = 0.046). Compared with the moderate and severe pollution periods, the short- and medium-term LFR (FVC, FEV1, MEF50) of patients in the mild pollution period were faster and better (P < 0.001, P < 0.001, P < 0.001, P = 0.048, P = 0.010, P = 0.013, respectively). Thus, exposure to high PM2.5 levels was associated with significantly reduced speed and degree of short- and medium-term LFR in patients who underwent lobectomy.


Assuntos
Poluentes Atmosféricos , Adulto , Humanos , Poluentes Atmosféricos/análise , Exposição Ambiental , Recuperação de Função Fisiológica , Material Particulado/análise , Pulmão
10.
Nanoscale ; 12(13): 7035-7044, 2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32207505

RESUMO

Owing to the capacity of efficiently harvesting and converting incident energy, localized surface-plasmon resonance of noble metals was introduced into a metal-semiconductor design for promoting hydrogen evolution. In this study, a plasmonic nanodumbbell structure was employed to strategically modulate the energy transfer in the water reduction reaction. A maximum H2 evolution rate of 80 µmol g-1 h-1 was obtained in the Au-TiO2 nanodumbbells, and further improvement was achieved through surface modification with Pt nanoparticles functioning as active sites, leading to ∼4.3 times enhanced photocatalytic activity. Compared with similar nanostructures reported previously, the present superior photoactivity response is ascribed to the injection process of the energetic hot electrons generated from the excitation and decay of the longitudinal surface-plasmon resonance (LSPR) and transverse surface-plasmon resonance (TSPR) in the Au nanorods, which corresponds to the electric field distribution of the finite-difference-time-domain simulation. These intriguing results, originating from the positive synergistic effect of the plasmon and co-catalyst, demonstrated the mechanism of the plasmon-assisted photochemistry and provided a promising strategy for the rational design of novel plasmonic photocatalysts.

11.
Ying Yong Sheng Tai Xue Bao ; 30(12): 4177-4185, 2019 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-31840463

RESUMO

Soil compaction and nutrient deficiency are common problems in Ningxia Yellow River pumping irrigation area, which adversely affect crop yield. A two-year (2017-2018) field experiment of straw returning combined with nitrogen fertilizer were designed. Four nitrogen application levels (pure N with 0, 150, 300 and 450 kg·hm-2) were set under the condition of full smashing of maize straw (12000 kg·hm-2) returning, with the conventional nitrogen application (pure N with 225 kg·hm-2) without straw returning as the control (CK) to investigate the effects of straw returning combined with different amounts of nitrogen fertilizer on soil physical and chemical properties and maize yield under drip irrigation condition. The results showed that, compared with no-straw returning treatment, the treatments of straw returning combined nitrogen fertilizer with 300 and 450 kg·hm-2 reduced soil bulk density (0-20 cm) by 3.3% and 5.4%, but increased soil porosity by 3.7% and 7.1%, respectively. Straw returning combined with nitrogen with 300 kg·hm-2 and 450 kg·hm-2 was the best treatment which increased soil organic matter content, available K, P, alkaline N and total N in 0-40 cm soil layer. Compared with the non-returning treatment, straw returning combined with nitrogen fertilizer 300 kg·hm-2 significantly increased soil water storage by 13.6% and 22.1%, increased maize yield by 31.1% and 46.0 % in 2017 and 2018, respectively. The analysis of yield components showed that the high maize yield was achieved mainly by increasing grain number and the100-grain weight. Curve fitting showed that the optimum amount of nitrogen fertilizer was 260 kg·hm-2. Our results provide important basis for soil fertility improvement and sustainable production.


Assuntos
Fertilizantes , Solo , Agricultura , China , Nitrogênio , Rios , Zea mays
12.
Nanoscale ; 11(47): 22971-22979, 2019 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-31769772

RESUMO

As a coordination polymer built of [Mo3S13]2- clusters, amorphous nanoscale MoSx (a-MoSx) is an attractive electrocatalyst for the hydrogen evolution reaction (HER) due to its abundant active sites and scalable synthesis. However, clarifying the internal catalytic mechanism and achieving even higher HER performance with scalable size are still challenging. Herein, a new hybrid catalyst of a-MoSx flakes decorated with Ni3S2 nanocrystals (size < 10 nm) has been successfully synthesized on 10 × 20 cm2-sized Ni foam by a portable hydrothermal route. As the strong interaction of [Mo3S13]2- clusters with Ni3S2 is evidenced by comprehensive binding state and Raman characterization, the polymerization effect of [Mo3S13]2- itself and the perfect interfaces between [Mo3S13]2- clusters and Ni3S2 are also confirmed by density functional theory calculations. These two factors greatly lower the absorption energy of hydrogen nearly to zero, leading to much improved HER activity. Current densities of 100 and 600 mA cm-2 are achieved at overpotentials of 181 and 246 mV, respectively, which are so far the highest values approaching practical applications. The findings of this work provide a fundamental reference about the catalytic origin of a-MoSx based catalysts, and shed light on the practical applications of non-precious electrocatalysts for their compatibility with low cost batch production.

13.
RSC Adv ; 9(7): 4001-4007, 2019 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-35518076

RESUMO

Cd x Zn1-x S nanocrystals with sizes ranging from 3-11 nm were synthesized by a simple organic solution method. The nanocrystals possess a cubic zinc-blende structure and the bandgap blue-shifts from 2.1 eV to 3.4 eV by increasing the composition of Zn ions in the solid solutions. After a facile ligand exchange process, the photocatalytic activity for H2 production of the Cd x Zn1-x S nanocrystals was investigated under visible-light irradiation (λ ≥ 420 nm) with Na2SO3/Na2S as the electron donor. It was found that the Cd0.8Zn0.2S had the highest photoactivity with H2 evolution rate of 6.32 mmol g-1 h-1. By in situ adding Pt precursors into the reaction solution, inhomogenous Pt-Cd x Zn1-x S nanoheterostructures were formed, which accounted for a 30% enhancement for the H2 evolution rate comparing with that of pure Cd0.8Zn0.2S nanocrystals. This work highlights the use of facile organic synthesis in combination with suitable surface modification to enhance the activity of the photocatalysts.

14.
ACS Nano ; 13(9): 10085-10094, 2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31436948

RESUMO

Integrating metallic halide perovskites with established modern semiconductor technology is significant for promoting the development of application-level optoelectronic devices. To realize such devices, exploring the growth dynamics and interfacial carrier dynamics of perovskites deposited on the core materials of semiconductor technology is essential. Herein, we report the incommensurate heteroepitaxy of highly oriented single-crystal cesium lead bromide (CsPbBr3) on c-wurtzite GaN/sapphire substrates with atomically smooth surface and uniform rectangular shape by chemical vapor deposition. The CsPbBr3 microplatelet crystal exhibits green-colored lasing under room temperature and has a structural stability comparable with that grown on van der Waals mica substrates. Time-resolved photoluminescence spectroscopy studies show that the type-II CsPbBr3-GaN heterojunction effectively enhances the separation and extraction of free carriers inside CsPbBr3. These findings provide insights into the fabrication and application-level integrated optoelectronic devices of CsPbBr3 perovskites.

15.
Sci Total Environ ; 622-623: 394-401, 2018 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29220764

RESUMO

Extensive research has focused on modelling and analysis of urban flooding in relatively small catchments. Findings in small areas tend to be site-specific, and may not be applicable to larger study areas. Larger scale studies can identify general patterns and influential factors; however, few studies have investigated urban flooding on a larger scale such as a metropolitan area. In this study, we explored the spatial-temporal patterns of urban flooding during the period of 2009-2015 in the central area of Guangzhou, China. Under the framework of Pressure (precipitation and impervious surface)-State (urban flooding)-Response (drainage improvement), we evaluated reasons for the State change and effectiveness of the Response. Overall the urban flooding state showed a fluctuating and improving trend. The fluctuation of the flooding state trend is due to precipitation variation, and the improving trend is attributed to drainage improvement. Furthermore, drainage improvement in the upstream area had led to new flooding in the downstream area. It is evident that the mitigation effect of urban flooding in Guangzhou varied significantly across the city. It is further suggested to regularly collect urban flooding records in cities with flood risk, so that more appropriate policies and measures about urban flooding mitigation can be developed.

16.
Nanoscale Res Lett ; 13(1): 31, 2018 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-29396789

RESUMO

Ni2P has been decorated on CdS nanowires or nanorods for efficient photocatalytic H2 production, whereas the specific surface area remains limited because of the large size. Here, the composites of Cd0.5Zn0.5S quantum dots (QDs) on thin Ni2P porous nanosheets with high specific surface area were constructed for noble metal-free photocatalytic H2 generation. The porous Ni2P nanosheets, which were formed by the interconnection of 15-30 nm-sized Ni2P nanoparticles, allowed the uniform loading of 7 nm-sized Cd0.5Zn0.5S QDs and the loading density being controllable. By tuning the content of Ni2P, H2 generation rates of 43.3 µM h- 1 (1 mg photocatalyst) and 700 µM h- 1 (100 mg photocatalyst) and a solar to hydrogen efficiency of 1.5% were achieved for the Ni2P-Cd0.5Zn0.5S composites. The effect of Ni2P content on the light absorption, photoluminescence, and electrochemical property of the composite was systematically studied. Together with the band structure calculation based on density functional theory, the promotion of Ni2P in charge transfer and HER activity together with the shading effect on light absorption were revealed. Such a strategy can be applied to other photocatalysts toward efficient solar hydrogen generation.

17.
Adv Mater ; 30(31): e1801805, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29923237

RESUMO

1D nanowires of all-inorganic lead halide perovskites represent a good architecture for the development of polarization-sensitive optoelectronic devices due to their high absorption efficient, emission yield, and dielectric constants. However, among as-fabricated perovskite nanowires with the lateral dimensions of hundreds nanometers so far, the optical anisotropy is hindered and rarely explored owing to the invalidating of electrostatic dielectric mismatch in the physical dimensions. Here, well-aligned CsPbBr3 and CsPbCl3 nanowires with thickness T down to 15 and 7 nm, respectively, are synthesized using a vapor phase van der Waals epitaxial method. Strong emission anisotropy with polarization ratio up to ≈0.78 is demonstrated in the nanowires with T < 40 nm due to the electrostatic dielectric confinement. With the increasing of thickness, the polarization ratio remarkably reduces monotonously to ≈0.17 until T ≈140 nm; and further oscillates in a small amplitude owing to the wave characteristic of light. These findings not only represent a demonstration of perovskite-based polarization-sensitive light sources, but also advance fundamental understanding of their polarization properties of perovskite nanowires.

18.
Nanoscale Res Lett ; 12(1): 302, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28449547

RESUMO

In order to reduce the amount of inactive materials, such as binders and carbon additives in battery electrode, porous cobalt monoxide nanofibers were directly grown on conductive substrate as a binder/additive-free lithium-ion battery anode. This electrode exhibited very high specific discharging/charging capacities at various rates and good cycling stability. It was promising as high capacity anode materials for lithium-ion battery.

19.
Pest Manag Sci ; 73(8): 1655-1660, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27990754

RESUMO

BACKGROUND: The occurrence of Plasmopara viticola populations resistant to carboxylic acid amide (CAA) fungicides is becoming a serious problem in the control of grapevine downy mildew worldwide. The resistance is caused by point mutations in the PvCesA3 gene. These isolates with this mutation have been detected mainly by determining the minimum inhibitory concentration of fungicides, which is always time consuming and inefficient. RESULTS: To establish a suitable method for rapid detection of the G1105S mutation in P. viticola, an efficient and simple molecular method was developed, based on tetra-primer ARMS PCR. A set of four primers were designed and optimised to distinguish the different genotypes within one step. Only 2 h was required from the sampling of symptoms to the phenotyping of fungicide resistance. Using this method, CAA-resistant P. viticola were identified for the first time in China. Also, the finding of sensitive heterozygotes indicated that the resistant allele is spreading in the population in Ziyuan. CONCLUSION: This new method proved to be useful as an early warning system for resistance outbreaks of P. viticola to CAA fungicides in the field and may be helpful in decisions concerning rotation of different fungicide groups. © 2016 Society of Chemical Industry.


Assuntos
Amidas/farmacologia , Ácidos Carboxílicos/química , Primers do DNA/genética , Farmacorresistência Fúngica/genética , Oomicetos/genética , Fenótipo , Reação em Cadeia da Polimerase/métodos , Amidas/química , Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Mutação , Oomicetos/efeitos dos fármacos , Fatores de Tempo
20.
ACS Appl Mater Interfaces ; 9(27): 22560-22567, 2017 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-28621130

RESUMO

Carbon dots (C dots, size < 10 nm) have been conventionally decorated onto semiconductor matrixes for photocatalytic H2 evolution, but the efficiency is largely limited by the low loading ratio of the C dots on the photocatalyst. Here, we propose an inverse structure of Cd0.5Zn0.5S quantum dots (QDs) loaded onto the onionlike carbon (OLC) matrix for noble metal-free photocatalytic H2 evolution. Cd0.5Zn0.5S QDs (6.9 nm) were uniformly distributed on an OLC (30 nm) matrix with both upconverted and downconverted photoluminescence property. Such an inverse structure allows the full optimization of the QD/OLC interfaces for effective energy transfer and charge separation, both of which contribute to efficient H2 generation. An optimized H2 generation rate of 2018 µmol/h/g (under the irradiation of visible light) and 58.6 µmol/h/g (under the irradiation of 550-900 nm light) was achieved in the Cd0.5Zn0.5S/OLC composite samples. The present work shows that using the OLC matrix in such a reverse construction is a promising strategy for noble metal-free solar hydrogen production.

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