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1.
Nanoscale Res Lett ; 14(1): 371, 2019 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-31820137

RESUMO

The near-infrared (NIR) photoelectric properties of multilayer Bi2O2Se nanofilms were systematically studied in this paper. Multilayer Bi2O2Se nanofilms demonstrate a sensitive photo response to NIR, including a high photoresponsivity (~ 101 A/W), a quick response time (~ 30 ms), a high external quantum efficiency (~ 20,300%), and a high detection rate (1.9 × 1010 Jones). These results show that the device based on multilayer Bi2O2Se nanofilms might have great potentials for future applications in ultrafast, highly sensitive NIR optoelectronic devices.

2.
Artif Cells Nanomed Biotechnol ; 47(1): 4211-4221, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31713444

RESUMO

At present, cancer is the first cause of death for humans, but early detection and treatment can help improve prognoses and reduce mortality. However, further development of carrier-assistant drug delivery systems (DDSs) is retarded by the aspects such as the low drug-carrying capacity, carrier-induced toxicity and immunogenicity, complex synthesis manipulation. The development of nanoscale drug delivery systems (NDDS) have been rapidly developed to address these issues. In this article, we used PLGA-PEG with good biocompatibility to encapsulate Fe3O4 nanoparticles (a magnetic resonance imaging contrast agent) and DOX (an antitumour drug) via the emulsion-solvent evaporation method, aimed at achieving a dual function of the early detection and the treatment of mammary cancer. The results showed that the Fe3O4/DOX/PLGA-PEG nanoparticles had a relatively uniform size, a high carrier rate of Fe3O4 and high encapsulation efficiency of DOX, and a relatively high activity of released DOX within 120 h. In addition, in vitro studies showed that the Fe3O4/DOX/PLGA-PEG nanoparticles were cytocompatibility in NIH 3T3 fibroblast cells culture study while had a special effect on destroying human breast cancer MCF-7 cells compared with pure DOX solution. In vitro studies revealed that the Fe3O4/DOX/PLGA-PEG enabled enhanced T2 contrast magnetic resonance. Overall, our multifunctional Fe3O4/DOX/PLGA-PEG nanoparticles, composed of biocompatible substances and therapeutic/imaging materials, have great potential for the early detection of cancer and accurate drug delivery via the dynamic monitoring using MRI.

3.
Nanoscale ; 11(48): 23498-23501, 2019 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-31777899

RESUMO

Removal of expression of concern for 'Controllable 2H-to-1T' phase transition in few-layer MoTe2' by Yuan Tan et al., Nanoscale, 2018, 10, 19964-19971.

4.
Artigo em Inglês | MEDLINE | ID: mdl-31605126

RESUMO

A two-phased retrospective cross-sectional study analysed the occupational dose and radiation protection practice among medical workers in two hospitals in the UAE. Phase 1 evaluated radiation protection practice using a questionnaire, whereas phase 2 assessed the occupational dose. Readings of 952 thermoluminescence dosimeters were analyzed. The result showed 52% of medical workers have a good level of radiation protection practice. Readings of 952 thermoluminescence dosimeters were analyzedAverage annual effective dose per worker ranged from 0.39 to 0.83 mSv. Cardiologists and nurses displayed a higher average of occupational radiation dose compared to other workers. There were no significant correlations between radiation protection practice and hospital, occupation or department. Finally, the occupational dose was within the international and national limits, but the reduction of radiation dose to cardiologist and nurses is essential. Moreover, training is essential to promote radiation safe practice among medical workers.

5.
Nat Commun ; 10(1): 4201, 2019 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-31519986

RESUMO

As Charles Darwin anticipated, living fossils provide excellent opportunities to study evolutionary questions related to extinction, competition, and adaptation. Ginkgo (Ginkgo biloba L.) is one of the oldest living plants and a fascinating example of how people have saved a species from extinction and assisted its resurgence. By resequencing 545 genomes of ginkgo trees sampled from 51 populations across the world, we identify three refugia in China and detect multiple cycles of population expansion and reduction along with glacial admixture between relict populations in the southwestern and southern refugia. We demonstrate multiple anthropogenic introductions of ginkgo from eastern China into different continents. Further analyses reveal bioclimatic variables that have affected the geographic distribution of ginkgo and the role of natural selection in ginkgo's adaptation and resilience. These investigations provide insights into the evolutionary history of ginkgo trees and valuable genomic resources for further addressing various questions involving living fossil species.

6.
Small ; 15(43): e1904482, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31512402

RESUMO

Bi2 O2 Se is emerging as a photosensitive functional material for optoelectronics, and its photodetection mechanism is mostly considered to be a photoconductive regime in previous reports. Here, the bolometric effect is discovered in Bi2 O2 Se photodetectors. The coexistence of photoconductive effect and bolometric effect is generally observed in multiwavelength photoresponse measurements and then confirmed with microscale local heating experiments. The unique photoresponse of Bi2 O2 Se photodetectors may arise from a change of hot electrons during temperature rises instead of photoexcited holes and electrons. Direct proof of the bolometric effect is achieved by real-time temperature tracking of Bi2 O2 Se photodetectors under time evolution after light excitation. Moreover, the Bi2 O2 Se bolometer shows a high temperature coefficient of resistance (-1.6% K-1 ), high bolometric coefficient (-31 nA K-1 ), and high bolometric responsivity (>320 A W-1 ). These findings offer a new approach to develop bolometric photodetectors based on Bi2 O2 Se layered materials.

7.
Curr Drug Targets ; 2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31490747

RESUMO

BACKGROUND: The lipid bilayer of the plasma membrane is impermeable to ions, yet changes in the flux of ions across the cell membrane are critical regulatory events in cells. Because of their regulatory roles in a range of physiological processes, such as electrical signaling in muscles and neurons, to name a few, these proteins are one of the most important drug targets. OBJECTIVE: This review mainly focused on the computational approaches for elucidating protein-protein interactions in cation channel signaling. DISCUSSION: Due to continuously advanced facilities and technologies in computer sciences, the physical contacts of macromolecules of channel structures have been virtually visualized. Indeed, techniques like protein-protein docking, homology modeling, and molecular dynamics simulation are valuable tools for predicting the protein complex and refining channels with unreleased structures. Undoubtedly, these approaches will greatly expand the cation channel signaling research, thereby speeding up structure-based drug design and discovery. CONCLUSION: We introduced a series of valuable computational tools for elucidating protein-protein interactions in cation channel signaling, including molecular graphics, protein-protein docking, homology modeling, and molecular dynamics simulation.

8.
J Appl Psychol ; 2019 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-31343202

RESUMO

Drawing from the group engagement model of justice, we examine how and when higher abusive supervision relates to fewer safety behaviors and worse safety performance. In Study 1, a 2-wave survey study of 468 manufacturing technicians, we found that belongingness need satisfaction mediated the negative relationship between abusive supervision and safety behavior. In Study 2, a multiwave survey study of 589 airline pilots, we found that safety behavior mediated the adverse relationship between abusive supervision and downstream objective safety performance. Higher trait social standing uncertainty was associated with a stronger adverse relationship between abusive supervision and safety. Indirect relationships of abusive supervision with safety behavior (Study 1) and safety performance (Study 2) were stronger among individuals with higher social standing uncertainty. We discuss the theoretical implications of these findings for managing abusive supervision and safety at work. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

9.
Nanoscale ; 11(28): 13469-13476, 2019 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-31287485

RESUMO

The realization of p-n homojunctions, which can be achieved via spatially controlled carrier-type modulation, remains a challenge for two-dimensional transition metal dichalcogenides. Here, we report an effective method to tune intrinsic n-type few-layer MoSe2 to p-type through controlling precisely the ultraviolet-ozone treatment time, which can be attributed to the surface charge transfer from the underlying MoSe2 to MoOx (x < 3). The resulting hole mobility and concentration are ∼20.1 cm2 V-1 s-1 and ∼1.9 × 1012 cm-2, respectively, and the on-off ratio is ∼105, which are comparable to the values of pristine n-type MoSe2. Moreover, the lateral p-n homojunction prepared by partially treating MoSe2 displays a high rectification ratio of 2.4 × 104, an ideality factor of 1.1, and a high photoresponsivity of 0.23 A W-1 to the 633 nm laser at Vd = 0 V and Vg = 0 V due to the built-in potential in the p-n homojunction area. Our findings ensure the MoSe2 p-n diode as a promising candidate for future low-power operating photodevices.

10.
J Phys Chem Lett ; : 5027-5035, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31357864

RESUMO

Atomically thin transition-metal dichalcogenide (TMDC) heterostructures have attracted increasing attention because of their unprecedented potential in the fields of electronics and optoelectronics. However, selective growth of either lateral or vertical TMDC heterostructures remains challenging. Here, we report that lateral and vertical MoS2/MoSe2 epitaxial heterostructures can be successfully fabricated via a one-step growth strategy, which includes triggering by the concentration of sulfur precursor vapor and a high-temperature annealing process. Vertically stacked MoS2/MoSe2 heterostructures can be synthesized via control of the nucleation and growth kinetics, which is induced by high sulfur vapor concentration. The high-temperature annealing process results in the formation of fractured MoSe2 and in situ epitaxial growth of lateral MoSe2-MoS2 heterostructures. This study has revealed the importance of sulfur vapor concentration and high-temperature annealing processes in the controllable growth of MoSe2-MoS2 heterostructures, paving a new route for fabricating two-dimensional TMDC heterostructures.

11.
Nanomaterials (Basel) ; 9(5)2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31137613

RESUMO

This work reports the interlayer difference of exciton and phonon performance between the top and bottom layer of a bilayer-stacked two-dimensional materials structure (BSS). Through photoluminescence (PL) and Raman spectroscopy, we find that, compared to that of the bottom layer, the top layer of BSS demonstrates PL redshift, Raman E 2 g 1 mode redshift, and lower PL intensity. Spatial inhomogeneity of PL and Raman are also observed in the BSS. Based on theoretical analysis, these exotic effects can be attributed to substrate-coupling-induced strain and doping. Our findings provide pertinent insight into film-substrate interaction, and are of great significance to researches on bilayer-stacked structures including twisted bilayer structure, Van der Waals hetero- and homo-structure.

12.
Mol Biol Evol ; 36(5): 875-889, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30861529

RESUMO

The occurrence of parallel speciation strongly implies the action of natural selection. However, it is unclear how general a phenomena parallel speciation is since it was only shown in a small number of animal species. In particular, the adaptive process and mechanisms underlying the process of parallel speciation remain elusive. Here, we used an integrative approach incorporating population genomics, common garden, and crossing experiments to investigate parallel speciation of the wild rice species Oryza nivara from O. rufipogon. We demonstrated that O. nivara originated multiple times from different O. rufipogon populations and revealed that different O. nivara populations have evolved similar phenotypes under divergent selection, a reflection of recurrent local adaptation of ancient O. rufipogon populations to dry habitats. Almost completed premating isolation was detected between O. nivara and O. rufipogon in the absence of any postmating barriers between and within these species. These results suggest that flowering time is a "magic" trait that contributes to both local adaptation and reproductive isolation in the origin of wild rice species. Our study thus demonstrates a convincing case of parallel ecological speciation as a consequence of adaptation to new environments.


Assuntos
Especiação Genética , Oryza/genética , Adaptação Biológica , Ásia Sudeste , Ásia Ocidental , Ecossistema , Fenótipo , Filogeografia , Polimorfismo de Nucleotídeo Único , Isolamento Reprodutivo , Seleção Genética , Sequenciamento Completo do Genoma
13.
Front Psychol ; 10: 328, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30873073

RESUMO

The stock market in China has experienced significant turbulence since July 2014, including a bull market. In this paper, we propose that exposure to stock (defined as the condition of being exposed to both stock and stock-related information) can induce anxiety disorder when the market is in a turbulent period. To examine this prediction, we designed two studies in which we operationalized exposure to stock in two different ways. In Study 1, a panel analysis of a longitudinal data set for the Chinese stock market from January 2014 to July 2015 demonstrated that exposure to stock had a significant positive impact on individuals' anxiety disorder, even in a bull market. Study 2, employing priming experiments, further supported that a temporarily primed "stock mindset" subconsciously increased participants' anxiety. In addition, Study 2 revealed that physical exercise helped attenuate the detrimental impact of exposure to stock on mental well-being. This research demonstrates the detrimental impact of exposure to a turbulent stock market - even a rising market - on individuals' mental health. Furthermore, it identifies an effective way to buffer such impact, and suggests ways for social scientists to employ search engines and the related data sets to obtain psychological or behavioral information (especially emotions and emotion disorders) by examining longitudinal "Big Data."

14.
Hypertension ; 73(4): 893-899, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30776974

RESUMO

Arterial stiffness and blood pressure (BP) both increase with aging synchronously. Whether elevated BP results from thickening of arterial wall or vice versa is controversial in previous studies. This study included 17 862 participants without history of myocardial infarction, stroke, atrial fibrillation or flutter, or cancer and with brachial-ankle pulse wave velocity (baPWV) and BP measurements during 2010 to 2016. Age was calculated from the self-reported birthdate to the first date of baPWV examination. Mediation analyses were applied to assess the mediation effect by baPWV in the association between age and BP. Temporal relation between baPWV and BP was assessed by cross-lagged analyses among 1508 participants with repeated assessment of baPWV. We found that systolic BP increased 0.47 (95% CI, 0.45-0.49) mm Hg per 1 year older by the mediation effect of baPWV and that the direct effect of aging on systolic BP was -0.07 (95% CI, -0.09 to -0.05) mm Hg per 1 year older. The standard regression coefficient from baseline baPWV to follow-up systolic BP was 0.09 (95% CI, 0.04-0.15), which was greater than the standard regression coefficient from baseline systolic BP to follow-up baPWV (0.01; 95% CI, -0.04 to 0.06). Arterial stiffness mediated the positive association between aging and BP, and arterial stiffness might precede elevated BP. Clinical Trial Registration- URL: http://www.chictr.org.cn . Unique identifier: ChiCTR-TNRC-11001489.


Assuntos
Envelhecimento/fisiologia , Pressão Sanguínea/fisiologia , Hipertensão/epidemiologia , Rigidez Vascular/fisiologia , Fatores Etários , Índice Tornozelo-Braço , China/epidemiologia , Feminino , Seguimentos , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Morbidade/tendências , Estudos Prospectivos , Análise de Onda de Pulso , Fatores de Risco
15.
Nanoscale ; 10(42): 19964-19971, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30349910

RESUMO

Most two-dimensional (2D) transition metal dichalcogenides (TMDs) exhibit more than one structural phase, leading to a number of remarkable physics and potential device applications beyond graphene. Here, we demonstrated a feasible route to trigger 2H-to-1T' phase transition in few-layer molybdenum ditelluride (MoTe2) by laser irradiation. The effects of laser power and irradiation duration were systematically studied in this study, revealing the accumulated heating effect as the main driving force for such a phase transition. By carefully adjusting laser power and irradiation time, we could control the structural phases of MoTe2 as 2H, 2H + 1T', and 1T'. After thermal annealing at a rather low temperature, the laser-irradiated MoTe2 showed a completely suppressed 2H component and a more stabilized 1T' phase, demonstrating that the microscopic origin of the irreversible 2H-to-1T' phase transition is the formation of Te vacancies in MoTe2 due to laser local instantaneous heating. Our findings together with the unique properties of MoTe2 pave the way for high-performance nanoelectronics and optoelectronics based on 2D TMDs and their heterostructures.

16.
ACS Appl Mater Interfaces ; 10(36): 30045-30050, 2018 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-30146869

RESUMO

Growing uniform oxides with various thickness on TMDs is one of the biggest challenges to integrate TMDs into complementary metal oxide semiconductor (CMOS) logic circuits. Here, we report a layer-by-layer oxidation of atomically thin MoTe2 flakes via ozone (O3) exposure. The thickness of MoO x oxide film could be tuning with atomic-level accuracy simply by varying O3 exposure time. Additionally, MoO x-covered MoTe2 shows a hole-dominated transport behavior. Our findings point to a simple and effective strategy for growing homogeneous surface oxide film on MoTe2, which is promising for several purposes in metal-oxide-semiconductor transistor, ranging from surface passivation to dielectric layers.

17.
J Math Biol ; 77(5): 1589-1622, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30019238

RESUMO

The purpose of this paper is to develop a new coupled mathematical model of angiogenesis (new blood vessel growth) and tumor growth to study cancer development and anti-angiogenesis therapy. The angiogenesis part assumes the capillary to be a viscoelastic continuum whose stress depends on cell proliferation or death, and the tumor part is a Darcy's law model regarding the tumor mass as an incompressible fluid where the nutrient-dependent growth elicits volume change. For the coupled model, we provide both an inviscid analysis and a parameter sensitivity analysis of the angiogenesis model in response to a stationary hypoxic tumor, and a steady state analysis of the tumor growth in response to a fixed and long blood capillary. The analysis shows that the stable steady state tumor with an invading blood capillary exists if and only if the nutrient release rate divided by the decay rate is less than the tumor viable limit, and the full tumor encloses one part of the capillary in this steady state. Afterwards, we use the coupled model to simulate vascularized tumor growth and anti-angiogenesis therapy. The simulations show that the tumor tends to maximize the nutrient transfer by blood vessel co-option and the anti-angiogenesis treatment by using growth factor neutralizing antibodies would regress the neovasculature and shrink the tumor size. However, the shrunken tumor mass could survive by feeding on mature blood vessels that resist the treatment. This implies the limited efficacy of the anti-angiogenesis monotherapy and its effect on vessel normalization.

18.
Front Chem ; 6: 216, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29963548

RESUMO

In this work, mesoporous silica materials SBA-15 functionalized with propyl/ phenyl-sulfonic acid group were synthesized and loaded with Pt to form bifunctional catalysts. SAXRD, WAXRD, N2 adsorption-desorption, TEM techniques were used to characterize the above bifunctional catalysts. These bifunctional catalysts were applied to the reaction of hydrodeoxygenation (HDO) of bio-derived phenol (PhOH) to produce cyclohexane fuel and showed very good catalytic performances. There were strong synergies between the metal sites and the acid sites on the bifunctional catalysts. This reaction of phenol HDO provides a model system for the catalytic upgrading of biomass-derived fuel.

19.
Dalton Trans ; 47(30): 10124-10129, 2018 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-30003204

RESUMO

Four unprecedented decanuclear heterometallic [Ln2CoII4CoIII4] clusters based on a diethanolamine ligand (H2dea), namely [Eu2CoII4CoIII4(dea)8(HCOO)4(OH)2(Cl)2(CH3OH)2]Cl2·4CH3OH·2H2O (1), [Gd2CoII4CoIII4(dea)8(HCOO)4(OH)2(Cl)2(CH3OH)2]Cl2·4CH3OH·2H2O (2), [Tb2CoII4CoIII4(dea)8(HCOO)4(OH)2(Cl)2(CH3OH)2]Cl2·2CH3OH·4H2O (3) and [Dy2CoII4CoIII4(dea)8(HCOO)4(OH)2(Cl)2(CH3OH)2]Cl2·2CH3OH·4H2O (4) were synthesized through a facile solution method. Single-crystal X-ray diffraction analyses reveal that complexes 1-4 consist of a [Ln2CoII4CoIII4] core, which is constructed by bridging a quasi-double cuboidal [Ln2CoII2CoIII2] core with two [CoIICoIII] units. Electrospray ionization mass spectrometry (ESI-MS) using methanol solution reveals that complexes 1-4 are stable in the solution, and the clusters undergo three different substitution reactions (Cl- replaced by OH-, OH- replaced by CH3O- and HCOO- replaced by OH-/CH3O-) at the same time in the ionization state. Magnetic susceptibilities reveal ferromagnetic couplings within complexes 3 and 4, and the magnetocaloric effect (MCE) for 2 was also evaluated and the maximum entropy change (-ΔSm) value reaches 16.3 J kg-1 K-1 at about 3 K and 5 T.

20.
Plant Physiol ; 177(4): 1754-1771, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29914891

RESUMO

Genomic imprinting is an epigenetic phenomenon by which certain genes display differential expression in a parent-of-origin-dependent manner. Hundreds of imprinted genes have been identified from several plant species. Here, we identified, with a high level of confidence, 208 imprinted gene candidates from rice (Oryza sativa). Imprinted genes of rice showed limited association with the transposable elements, which contrasts with findings from Arabidopsis (Arabidopsis thaliana). Generally, imprinting in rice is conserved within a species, but intraspecific variation also was detected. The imprinted rice genes do not show signatures of selection, which suggests that domestication has had a limited evolutionary consequence on genomic imprinting. Although conservation of imprinting in plants is limited, we show that some loci are imprinted in several different species. Moreover, our results suggest that different types of epigenetic regulation can be established either before or after fertilization. Imprinted 24-nucleotide small RNAs and their neighboring genes tend to express alleles from different parents. This association was not observed between 21-nucleotide small RNAs and their neighboring genes. Together, our findings suggest that the regulation of imprinting can be diverse, and genomic imprinting has evolutionary and biological significance.


Assuntos
Regulação da Expressão Gênica de Plantas , Impressão Genômica , Oryza/genética , Cruzamentos Genéticos , Elementos de DNA Transponíveis , Epigênese Genética , Genoma de Planta , Família Multigênica , Proteínas de Plantas/genética , Plantas/genética , RNA de Plantas
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