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1.
Eur Spine J ; 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32008100

RESUMO

BACKGROUND: Pedicle screw and rod instrumentation based on titanium can produce satisfying strength and stiffness for spinal fusion. However, excessive stiffness produced by titanium rods may cause stress shielding. Thus, polyetheretherketone (PEEK) rods with a low modulus of elasticity were introduced as substitutes for titanium rods. The purpose of this paper is to compare the effectiveness of PEEK rods versus titanium alloy rods in anterior spinal fusion with a new sheep model. METHODS: Sheep models of anterior-posterior cervical fusion were innovatively adopted in our study. Twenty-four sheep were randomly divided into a control group and a treatment group that received anterior-posterior cervical fixation with titanium rods or PEEK rods, respectively. Then, surgical segments were harvested and assessed by X-ray, micro-CT and histological examination to evaluate the efficiency of bone fusion. RESULTS: No complications related to fixation were found during the research process. The results of the X-ray showed a stronger spinal fusion in the PEEK rod groups than in the titanium rod group at 12 weeks postoperatively, and both groups underwent bone fusion at 24 weeks postoperatively. The results of micro-CT showed that fixation with PEEK rods achieved better bone ingrowth at an early postoperative stage (12 weeks) compared to fixation with titanium rods (bone volume fraction (BVF): 20.26 ± 4.36% vs 14.48 ± 3.49%, p < 0.05). The same trend was detected in the histological analysis, where the mineralized bone fraction in the experiment group (21.01 ± 3.48%) was significantly higher than that in the control group (16.73 ± 2.95%). In addition, better osseointegration was found in the experiment group at the early postoperative stage at 12 weeks (bone apposition (BA): 16.22 ± 3.24% vs 11.67 ± 3.63%, p < 0.05). However, there were no significant differences at 24 weeks postoperatively. CONCLUSION: PEEK rods can be used safely in a sheep model of anterior-posterior cervical fixation. Compared to traditional titanium rods, earlier and more evident bone fusion was found in the PEEK rods group. These slides can be retrieved under Electronic Supplementary Material.

2.
Phys Rev Lett ; 124(2): 027203, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-32004033

RESUMO

Spin waves can probe the Dzyaloshinskii-Moriya interaction (DMI), which gives rise to topological spin textures, such as skyrmions. However, the DMI has not yet been reported in yttrium iron garnet (YIG) with arguably the lowest damping for spin waves. In this work, we experimentally evidence the interfacial DMI in a 7-nm-thick YIG film by measuring the nonreciprocal spin-wave propagation in terms of frequency, amplitude, and most importantly group velocities using all electrical spin-wave spectroscopy. The velocities of propagating spin waves show chirality among three vectors, i.e., the film normal direction, applied field, and spin-wave wave vector. By measuring the asymmetric group velocities, we extract a DMI constant of 16 µJ/m^{2}, which we independently confirm by Brillouin light scattering. Thickness-dependent measurements reveal that the DMI originates from the oxide interface between the YIG and garnet substrate. The interfacial DMI discovered in the ultrathin YIG films is of key importance for functional chiral magnonics as ultralow spin-wave damping can be achieved.

3.
J Phys Chem A ; 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32045237

RESUMO

Ammonium aminodiboranate (AADB) and diammoniate of diborane (DADB) are two isomers of ammonia borane (AB), which have been intensively studied for hydrogen storage. Their high hydrogen contents give them the high potential to serve as hydrogen storage materials. To explore their dehydrogenation pathways, molecular dynamics (MD) simulations with a reactive force field (ReaxFF) were applied. Temperature ramping simulations of their thermolysis were carried out. For AADB, at low temperatures, its hydrogen release can be realized mainly via inter-molecular dehydrogenations. As the temperature of the simulated system increases, the formations of B-N bonds begin to occur. In the case of DADB, we found that this molecule could release hydrogen at a lower temperature with the cleavage of B-N bond. The compositional analysis of the simulated systems was also conducted to monitor the potential intermediates along their dehydrogenation pathways. Our current work provides a detailed picture of the initial dehydrogenation steps of AADB and DADB, and highlights the difference in their respective dehydrogenation processes.

4.
Metabolism ; : 154182, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32061660

RESUMO

The impairment of podocyte protein filtration function caused by excessive mitochondrial calcium intake is a critical feature of diabetic nephropathy (DN). Ca2+ channel transient receptor potential cation channel subfamily V member 1 (TRPV1) has been reported to protect against ischemia-reperfusion induced acute renal injury, but there is no report about its role in DN. Here, we report that dietary capsaicin potently inhibits and reverses chronic renal structural and functional damages in db/db or streptozotocin (STZ)-induced diabetic mice in a TRPV1-dependent manner. Activation of TRPV1 by capsaicin alleviated hyperglycemia-induced mitochondrial dysfunction in podocytes, accompanied by reduced mitochondria-associated membranes (MAMs) formation and fewer Ca2+ transport from endoplasmic reticulum (ER) to mitochondria. Mechanistically, TRPV1-mediated transient Ca2+ influx activated 5' AMP-activated protein kinase (AMPK) that reduced the transcription of Fundc1, a key molecule participating in MAMs formation. Inhibition of AMPK or overexpression of Fundc1 obviously blocked the inhibitory effect of capsaicin on MAMs formation and functional decline in podocytes. These findings emphasize the critical role of mitochondrial Ca2+ homeostasis in the maintenance of normal renal function and suggest an effective intervention method to counteract DN.

5.
Gene ; 735: 144403, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-32004668

RESUMO

Melon (Cucumis melo L.), an economically beneficial crop widely cultivated around the world, is vulnerable to powdery mildew (PM). However, the studies on molecular mechanism of melon response to PM fungi is still limited. Long non coding RNAs (lncRNAs) have emerged as new regulators in plants response to biotic stresses. We predicted and identified the intricate regulatory roles of lncRNAs in melon response to PM fungi. A total of 539 lncRNAs were identified from PM-resistant (MR-1) and susceptible melon (Top Mark), in which 254 were significantly altered after PM fungi infection. Multiple target genes of lncRNAs were found to be involved in the hydrolysis of chitin, callose deposition and cell wall thickening, plant-pathogen interaction and plant hormone signal transduction pathway. Additionally, a total of 42 lncRNAs possess the various functions with microRNAs (miRNAs), including lncRNAs that are targeted by miRNAs and function as miRNA precursors or miRNA sponges. These findings provide a comprehensive view of potentially functional lncRNAs, corresponding target genes and related lncRNA-miRNA pairs, which will greatly increase our knowledge of the mechanism underlying susceptibility and resistance to PM in melon.

6.
J Phys Chem Lett ; : 1570-1577, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32013437

RESUMO

Because of its unique electronic band structure, molybdenum disulfide (MoS2) has been regarded as a star semiconducting material. However, direct growth of continuous and high-quality MoS2 films on SiO2/Si substrates is still very challenging. Here, we report a facile chemical vapor deposition (CVD) method based on synergistic modulation of precursor and Na2SO4 catalysis, realizing the centimeter scale growth of a continuous MoS2 film on SiO2/Si substrates. The as-grown MoS2 film had an excellent spatial homogeneity and crystal quality, with an edge length of the composite domain as large as 632 µm. Both experimental and theoretical results proved that Na tended to bond with SiO2 substrates rather than to interfere with as-grown MoS2. Thus, they showed decent and uniform electrical performance, with electron mobilities as high as 5.9 cm2 V-1 s-1. We believe our method will pave a new way for MoS2 toward real application in modern electronics.

7.
BMJ Open ; 10(2): e030738, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32051297

RESUMO

OBJECTIVES: Cetuximab plus leucovorin, fluorouracil and oxaliplatin (FOLFOX-4) is superior to FOLFOX-4 alone as a first-line treatment for patients with metastatic colorectal cancer with RAS wild-type (RAS wt mCRC), with significantly improved survival benefit by TAILOR, an open-label, randomised, multicentre, phase III trial. Nevertheless, the cost-effectiveness of these two regimens remains uncertain. The following study aims to determine whether cetuximab combined with FOLFOX-4 is a cost-effective regimen for patients with specific RAS wt mCRC in China. DESIGN: A cost-effectiveness model combined decision tree and Markov model was built to simulate pateints with RAS wt mCRC based on health states of dead, progressive and stable. The health outcomes from the TAILOR trial and utilities from published data were used respectively. Costs were calculated with reference to the Chinese societal perspective. The robustness of the results was evaluated by univariate and probabilistic sensitivity analyses. PARTICIPANTS: The included patients were newly diagnosed Chinese patients with fully RAS wt mCRC. INTERVENTIONS: First-line treatment with either cetuximab plus FOLFOX-4 or FOLFOX-4. MAIN OUTCOME MEASURES: The primary outcomes are costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs). RESULTS: Baseline analysis disclosed that the QALYs was increased by 0.383 caused by additional cetuximab, while an increase of US$62 947 was observed in relation to FOLFOX-4 chemotherapy. The ICER was US$164 044 per QALY, which exceeded the willingness-to-pay threshold of US$28 106 per QALY. CONCLUSIONS: Despite the survival benefit, cetuximab combined with FOLFOX-4 is not a cost-effective treatment for the first-line regime of patients with RAS wt mCRC in China. TRIAL REGISTRATION NUMBER: TAILOR trial (NCT01228734); Post-results.

9.
PLoS One ; 15(2): e0228308, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32012184

RESUMO

Eucryptorrhynchus scrobiculatus is an important wood-boring pest of Ailanthus altissima in China, where it causes a large number of these trees to weaken or even die. To identify genes related to economic traits or specific cellular processes in E. scrobiculatus, gene expression in multiple tissue/organ samples is commonly surveyed, and reference genes are required in this process as a control for normalization. In the present study, 18 candidate reference genes from E. scrobiculatus were identified, and the expression levels of these reference genes were estimated through quantitative real-time PCR. Differences in expression levels were analyzed with four algorithms (geNorm, NormFinder, BestKeeper and delta Ct) and comprehensively with RefFinder. With the most stable levels of expression in different tissues, RPL13, RPS3 and RPL36 were determined to be suitable for use as candidate reference genes. Moreover, the expression profile of one target gene (glycoside hydrolase family 45, GH45) confirmed the reliability of the selected candidate reference genes. This study provides the first set of suitable candidate reference genes for gene expression studies in E. scrobiculatus, and the findings will facilitate subsequent transcriptomics and functional gene research on this pest.

10.
PLoS One ; 15(2): e0227840, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32023283

RESUMO

Flax seed has become consumers' choice for not only polyunsaturated alpha-linolenic fatty acid but also nutraceuticals such as lignans and soluble fiber. There is, however, a major drawback of flax as a source of functional food since the seeds contain significant level of cyanogenic glucosides. The final step of cyanogenic glucoside biosynthesis is mediated by UDP-glucose dependent glucosyltransferase. To date, no flax cyanogenic glucosyl transferase genes have been reported with verified biochemical functionality. Here we present a study on the identification and enzymatic characterization of a first flax cyanogenic glucosyltransferase, LuCGT1. We show that LuCGT1 was highly active towards both aliphatic and aromatic substrates. The LuCGT1 gene is expressed in leaf tissues as well as in developing seeds, and its expression level was drastically reduced in flax mutant lines low in cyanogenic glucosides. Identification of LuCGT1 provides a molecular handle for developing gene specific markers for targeted breeding of low cyanogenic glucosides in flax.

11.
Chem Commun (Camb) ; 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32040110

RESUMO

Here, a hollowed-out Au@AgPt core-frame nanostructure is carved in the presence of PtCl62- via galvanic replacement (GR) reaction, during which the dissolution of Ag atoms from the {100} facets and the deposition of Pt atoms on the active edges of the nanocubes occur. Both ex situ and in situ monitoring of the plasmonic and structural evolutions at the single-particle level, confirmed also by theoretical simulations, shows a three-phase mechanism involved.

12.
J Med Syst ; 44(2): 46, 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31897864

RESUMO

Images are powerful tools with which to convey human emotions, with different images stimulating diverse emotions. Numerous factors affect the emotions stimulated by the image, and many researchers have previously focused on low-level features such as color, texture and so on. Inspired by the successful use of deep convolutional neural networks (CNN) in the visual recognition field, we used a data augmentation method for small data sets to gain the sufficient number of the training dataset. In this paper, we use low-level features (color and texture features) of the image to assist the extraction of advanced features (image object category features and deep emotion features of images), which are automatically learned by deep networks, to obtain more effective image sentiment features. Then, we use the stack sparse auto-encoding network to recognize the emotions evoked by the image. Finally, high-level semantic descriptive phrases including image emotions and objects are output. Our experiments are carried out on the IAPS and GAPED data sets of the dimension space and the artphoto data set of the discrete space. Compared with the traditional manual extraction methods and other existing models, our method is superior to in terms of test performance.

13.
J Exp Clin Cancer Res ; 39(1): 19, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31959225

RESUMO

In the original publication of this manuscript [1], Fig. 6 contains a repeated image in error (the left image of 'Migration' and the left image of 'Invasion').

14.
ACS Nano ; 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31961130

RESUMO

Stacking order has a strong influence on the coupling between the two layers of twisted bilayer graphene (BLG), which in turn determines its physical properties. Here, we report the investigation of the interlayer coupling of the epitaxially grown single-crystal 30°-twisted BLG on Cu(111) at the atomic scale. The stacking order and morphology of BLG is controlled by a rationally designed two-step growth process, that is, the thermodynamically controlled nucleation and kinetically controlled growth. The crystal structure of the 30°-twisted bilayer graphene (30°-tBLG) is determined to have quasicrystal-like symmetry. The electronic properties and interlayer coupling of the 30°-tBLG are investigated using scanning tunneling microscopy and spectroscopy. The energy-dependent local density of states with in situ electrostatic doping shows that the electronic states in two graphene layers are decoupled near the Dirac point. A linear dispersion originated from the constituent graphene monolayers is discovered with doubled degeneracy. This study contributes to controlled growth of twist-angle-defined BLG and provides insights on the electronic properties and interlayer coupling in this intriguing system.

15.
J Am Chem Soc ; 142(6): 2726-2731, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31985227

RESUMO

Two-dimensional (2D) semiconductors hold great promise in flexible electronics because of their intrinsic flexibility and high electrical performance. However, the lack of facile synthetic and subsequent device fabrication approaches of high-mobility 2D semiconducting thin films still hinders their practical applications. Here, we developed a facile, rapid, and scalable solution-assisted method for the synthesis of a high-mobility semiconducting oxyselenide (Bi2O2Se) thin film by the selenization and decomposition of a precursor solution of Bi(NO3)3·5H2O. Simply by changing the rotation speed in spin-coating of the precursor solution, the thicknesses of Bi2O2Se thin films can be precisely controlled down to few atomic layers. The as-synthesized Bi2O2Se thin film exhibited a high Hall mobility of ∼74 cm2 V-1 s-1 at room temperature, which is much superior to other 2D thin-film semiconductors such as transition metal dichalcogenides. Remarkably, flexible top-gated Bi2O2Se transistors showed excellent electrical stability under repeated electrical measurements on flat and bent substrates. Furthermore, Bi2O2Se transistor devices on muscovite substrates can be readily transferred onto flexible polyvinyl chloride (PVC) substrates with the help of thermal release tape. The integration of a high-mobility thin-film semiconductor, excellent stability, and easy transfer onto flexible substrates make Bi2O2Se a competitive candidate for future flexible electronics.

16.
Phytochemistry ; 172: 112260, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31982646

RESUMO

Six undescribed quinoline alkaloids, named dasycarines A-E, and 18 known ones were isolated from the root bark of Dictamnus dasycarpus. All the structures were elucidated on the basis of comprehensive analysis of UV, IR, NMR, and HRMS spectroscopic data, and the absolute configurations were assigned via comparison of the calculated and experimental ECD data. (+)-Dasycarine A (1a) and (-)-Dasycarine A (1b) are a pair of enantiomers of dimeric furoquinoline alkaloid, which are the first dimeric via [2 + 2] cycloaddition of furan. The structure and absolute configuration of (-)-dasycarine A was determined via X-ray crystallography. Additionally, all the isolated compounds were tested for their inhibitory effects on NO production stimulated by LPS in BV-2 microglial cells. Three compounds showed strong inhibition with IC50 values below 5.0 µM; nine compounds exhibited inhibition with IC50 values in the range of 7.8-28.4 µM. Furthermore, we demonstrated that preskimmianine suppressed the levels of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and nuclear factor kappa B (NF-κB) in LPS-induced BV-2 microglial cells.

17.
Mol Cells ; 43(1): 48-57, 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-31910336

RESUMO

The microalga Chlamydomonas reinhardtii accumulates triacylglycerols (TAGs) in lipid droplets under stress conditions, such as nitrogen starvation. TAG biosynthesis occurs mainly at the endoplasmic reticulum (ER) and requires fatty acid (FA) substrates supplied from chloroplasts. How FAs are transferred from chloroplast to ER in microalgae was unknown. We previously reported that an Arabidopsis thaliana ATP-binding cassette (ABC) transporter, AtABCA9, facilitates FA transport at the ER during seed development. Here we identified a gene homologous to AtABCA9 in the C. reinhardtii genome, which we named CrABCA2. Under nitrogen deprivation conditions, CrABCA2 expression was upregulated, and the CrABCA2 protein level also increased. CrABCA2 knockdown lines accumulated less TAGs and CrABCA2 overexpression lines accumulated more TAGs than their untransformed parental lines. Transmission electron microscopy showed that CrABCA2 was localized in swollen ER. These results suggest that CrABCA2 transports substrates for TAG biosynthesis to the ER during nitrogen starvation . Our study provides a potential tool for increasing lipid production in microalgae.

18.
Nat Commun ; 11(1): 541, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31992713

RESUMO

The fast development of high-resolution electron microscopy (EM) demands a background-noise-free substrate to support the specimens, where atomically thin graphene membranes can serve as an ideal candidate. Yet the preparation of robust and ultraclean graphene EM grids remains challenging. Here we present a polymer- and transfer-free direct-etching method for batch fabrication of robust ultraclean graphene grids through membrane tension modulation. Loading samples on such graphene grids enables the detection of single metal atoms and atomic-resolution imaging of the iron core of ferritin molecules at both room- and cryo-temperature. The same kind of hydrophilic graphene grid allows the formation of ultrathin vitrified ice layer embedded most protein particles at the graphene-water interface, which facilitates cryo-EM 3D reconstruction of archaea 20S proteasomes at a record high resolution of ~2.36 Å. Our results demonstrate the significant improvements in image quality using the graphene grids and expand the scope of EM imaging.


Assuntos
Grafite/química , Microscopia Eletrônica/instrumentação , Microscopia Eletrônica/métodos , Fenômenos Químicos , Microscopia Crioeletrônica/métodos , Elétrons , Desenho de Equipamento , Processamento de Imagem Assistida por Computador , Membranas , Polímeros , Proteínas
19.
J Biomed Opt ; 25(1): 1-14, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31970943

RESUMO

Significance: As a promising hybrid imaging technique with x-ray excitable nanophosphors, cone-beam x-ray luminescence computed tomography (CB-XLCT) has been proposed for in-depth biological imaging applications. In situations in which the full rotation of the imaging object (or x-ray source) is inapplicable, the x-ray excitation is limited by geometry, or a lower x-ray excitation dose is mandatory, limited view CB-XLCT reconstruction would be essential. However, this will result in severe ill-posedness and poor image quality.

Aim: The aim is to develop a limited view CB-XLCT imaging strategy to reduce the scanning span and a corresponding reconstruction method to achieve robust imaging performance.

Approach: In this study, a group sparsity-based reconstruction method is proposed with the consideration that nanophosphors usually cluster in certain regions, such as tumors or major organs such as the liver. In addition, depth compensation (DC) is adopted to avoid the depth inconsistency caused by a limited view strategy.

Results: Experiments using numerical simulations and physical phantoms with different edge-to-edge distances were carried out to illustrate the validity of the proposed method. The reconstruction results showed that the proposed method outperforms conventional methods in terms of localization accuracy, target shape, image contrast, and spatial resolution with two perpendicular projections.

Conclusions: A limited view CB-XLCT imaging strategy with two perpendicular projections and a reconstruction method based on DC and group sparsity, which is essential for fast CB-XLCT imaging and for some practical imaging applications, such as imaging-guided surgery, is proposed.

20.
MAGMA ; 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31897903

RESUMO

OBJECTIVES: There is a controversy about the D* and f values of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) for mid- and long-term efficacy monitoring of tumor blood perfusion. To monitor the antitumor efficacy of the F/A-PLGA@DOX/SPIO nanosystem via IVIM-DWI and to explore the value of parameters pseudo-diffusion (D*) and fraction of pseudo-diffusion (f) for evaluating therapeutic effect in non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Thirty-six A549 tumor-bearing mice were divided randomly into three groups (each n = 12). Group 1 (G1) was injected with saline (the control group). Group 2 (G2) and group 3(G3) were injected with DOX and F/A-PLGA@DOX/SPIO, respectively. Each group underwent IVIM-DWI scanning at baseline and 3, 14, 21, and 28 days after treatment. D* and f values were derived using GE AW 4.5 post-processing station. All mice were sacrificed for pathological examination. RESULTS: The D* value of all three groups showed an upward trend, with the highest increase in G1 and the lowest in G3. Conversely, the f value of all groups trended to decrease within 7 days, of which G3 showed the most significant decline. Immunohistochemical staining revealed that vascular endothelial growth factor (VEGF)-positive staining rate and the microvessel density (MVD) of the tumors in G3 were significantly lower than those of the other groups (P < 0.05). The D* and f values were significantly and positively correlated to CD31 (r = 0.654, P < 0.001; r = 0.712, P < 0.001) and VEGF (r = 0.694, P < 0.001; r = 0.664, P < 0.001). CONCLUSION: IVIM-DWI-derived parameters D* and f are valuable indicators for the evaluation of the antitumor microcirculation changes of multifunctional nanosystem.

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