Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 578
Filtrar
1.
J Hepatol ; 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34509526

RESUMO

BACKGROUND & AIMS: Intrahepatic cholangiocarcinoma (ICC) is a primary liver cancer with high aggressiveness and extremely poor prognosis. The role of circular RNAs (circRNAs) in ICC carcinogenesis and progression remains to be determined. METHODS: CircRNA microarray was performed to screen significantly up-regulated circRNAs in paired ICC and non-tumor tissues. Colony formation, transwell, and xenograft models were used to examine the role of circRNAs in ICC proliferation and metastasis. RNA pulldown, mass spectrometry, chromatin immunoprecipitation, RNA binding protein immunoprecipitation, chromatin isolation by RNA purification, electrophoretic mobility shift assay, and luciferase reporter assays were used to explore the molecular sponge role of the circRNA via binding to miRNAs, and the interaction between circRNA and RNA-binding proteins. RESULTS: Hsa_circ_0050898, which originated from exon 1 to exon 20 of the ACTN4 gene (named as circACTN4), was significantly upregulated in ICC. High circACTN4 expression was associated with enhanced tumor proliferation and metastasis in vitro and in vivo, as well as a worse prognosis following ICC resection. In addition, circACTN4 upregulated Yes-associated protein1 (YAP1) expression by sponging miR-424-5p. More importantly, circACTN4 also recruited Y-box binding protein 1 (YBX1) to stimulate Frizzled-7 (FZD7) transcription. Furthermore, circACTN4 overexpression in ICC cells enhanced the interaction between YAP1 and ß-catenin, which are the core components of the Hippo and Wnt signaling pathways, respectively. CONCLUSIONS: CircACTN4 was upregulated in ICC and promoted ICC proliferation and metastasis by acting as a molecular sponge of miR-424-5p, as well as by interacting with YBX1 to transcriptionally activate FZD7. These results suggested that circACTN4 is a potential prognostic marker and therapeutic target for ICC. LAY SUMMARY: A circular RNA (circACTN4) was highly expressed in intrahepatic cholangiocarcinoma (ICC). The expression level of circACTN4 was positively associated with tumor growth and metastasis through both the Hippo and Wnt signaling pathways.

2.
Langmuir ; 37(38): 11422-11428, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34519205

RESUMO

It is a great challenge to precisely control the molecules that self-assemble into diverse shapes with diverse properties. Herein, the self-assembled behaviors between calixpyridinium and two pyrenesulfonate guests, 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt (PyTS) and sodium 1-pyrenesulfonate (PS), were studied. The morphology and property of the two assemblies were quite different. PS guests self-assembled into spherical aggregates upon complexation with calixpyridinium, while the self-assembled rodlike aggregates were formed via the binding between calixpyridinium and PyTS guests. The calixpyridinium-PS supramolecular aggregates could not emit fluorescence in the solid state, while a strong green fluorescence was emitted by the calixpyridinium-PyTS supramolecular aggregates in the solid state. More interestingly and importantly, the solid calixpyridinium-PyTS supramolecular aggregates exhibited an adsorbent ability to iodine in both the aqueous solution and the vapor phase, while the solid calixpyridinium-PS supramolecular aggregates could not capture iodine. The diverse iodine capture capability of the two supramolecular aggregates was determined by the self-assembled structure at the molecular level.

3.
Mater Sci Eng C Mater Biol Appl ; 129: 112386, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34579905

RESUMO

Bone pain is the primary problem for patients with osteoporosis. Ketoprofen is clinically used to treat osteoporotic pain, while long-term oral administration of ketoprofen can cause some side effects. In addition, osteoporosis is also accompanied by bone mass loss and inflammation. In this study, we designed a multifunctional drug (Ket@Mg-MOF-74) adopted Mg-MOF-74 to load ketoprofen to treat osteoporotic pain, bone loss and inflammation comprehensively. Mg-MOF-74 was prepared, and the physicochemical characterization proved that it had excellent physical and chemical stability. Ket@Mg-MOF-74 was synthesized by post-synthetic modification method and a high loading rate of ketoprofen was confirmed. Drug release and ion release experiments indicated Ket@Mg-MOF-74 had a good controlled release of ketoprofen and Mg in solution. Cell experiments in vitro proved the compound drug could significantly reduce the expression of pain-related genes of cyclooxygenase 2 (COX2), obviously up-regulated the expression of osteogenic cytokines and remarkably down-regulated the secretion of pro-inflammatory factors. Therefore, Ket@Mg-MOF-74 is believed a promising painkiller for osteoporotic bone pain, with the function of anti-inflammatory and promoting bone formation.


Assuntos
Cetoprofeno , Preparações Farmacêuticas , Anti-Inflamatórios não Esteroides , Liberação Controlada de Fármacos , Humanos , Dor
4.
ACS Biomater Sci Eng ; 7(10): 4809-4818, 2021 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-34558912

RESUMO

As a potential anticancer agent, azurin has attracted extensive attraction among chemists, physicists, and material scientists. Its structural and unfolding/folding information has been partially understood, but some detailed information, such as the difference in the unfolding processes between apo-azurin and holo-azurin, the mechanical stability, and the role of the copper cluster in its stability, has not been addressed adequately, especially at the single-molecule level. Here, we employed AFM-based single-molecule force spectroscopy to investigate the unfolding process of azurin in the apo and holo forms under an external force. The results indicated that the unfolding processes of apo-azurin and holo-azurin are different, and holo-azurin requires a stronger force to unfold than does apo-azurin. The copper cluster exhibited a more significant impact on the stability and the folding process of holo-azurin: the copper cluster was completely broken, and the copper ion left the unfolded azurin during the unfolding process of azurin. We suspected that the presence of the disulfide bond in azurin made the unfolding of the copper cluster different from that in pseudoazurin, which is also a type I copper protein like azurin. Rarely reported in previous studies, the mechanical strength of the Cu-N(His) bond of the copper cluster was obtained in this study, which is weaker than that of most metal-S(Cys) bonds but higher than that of the Fe-N(His) bond. Altogether, our results offer a possible new scenario for azurin to widely extend its anticancer activity.

5.
Sci Robot ; 6(57)2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34408096

RESUMO

Magnetic resonance (MR) imaging (MRI) provides compelling features for the guidance of interventional procedures, including high-contrast soft tissue imaging, detailed visualization of physiological changes, and thermometry. Laser-based tumor ablation stands to benefit greatly from MRI guidance because 3D resection margins alongside thermal distributions can be evaluated in real time to protect critical structures while ensuring adequate resection margins. However, few studies have investigated the use of projection-based lasers like those for transoral laser microsurgery, potentially because dexterous laser steering is required at the ablation site, raising substantial challenges in the confined MRI bore and its strong magnetic field. Here, we propose an MR-safe soft robotic system for MRI-guided transoral laser microsurgery. Owing to its miniature size (Ø12 × 100 mm), inherent compliance, and five degrees of freedom, the soft robot ensures zero electromagnetic interference with MRI and enables safe and dexterous operation within the confined oral and pharyngeal cavities. The laser manipulator is rapidly fabricated with hybrid soft and hard structures and is powered by microvolume (<0.004 milliter) fluid flow to enable laser steering with enhanced stiffness and lowered hysteresis. A learning-based controller accommodates the inherent nonlinear robot actuation, which was validated with laser path-following tests. Submillimeter laser steering accuracy was demonstrated with a mean error < 0.20 mm. MRI compatibility testing demonstrated zero observable image artifacts during robot operation. Ex vivo tissue ablation and a cadaveric head-and-neck trial were carried out under MRI, where we employed MR thermometry to monitor the tissue ablation margin and thermal diffusion intraoperatively.

6.
Sci Rep ; 11(1): 15612, 2021 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-34341398

RESUMO

Age-related macular degeneration (AMD) is a blinding eye disease with no unifying theme for its etiology. We used single-cell RNA sequencing to analyze the transcriptomes of ~ 93,000 cells from the macula and peripheral retina from two adult human donors and bulk RNA sequencing from fifteen adult human donors with and without AMD. Analysis of our single-cell data identified 267 cell-type-specific genes. Comparison of macula and peripheral retinal regions found no cell-type differences but did identify 50 differentially expressed genes (DEGs) with about 1/3 expressed in cones. Integration of our single-cell data with bulk RNA sequencing data from normal and AMD donors showed compositional changes more pronounced in macula in rods, microglia, endothelium, Müller glia, and astrocytes in the transition from normal to advanced AMD. KEGG pathway analysis of our normal vs. advanced AMD eyes identified enrichment in complement and coagulation pathways, antigen presentation, tissue remodeling, and signaling pathways including PI3K-Akt, NOD-like, Toll-like, and Rap1. These results showcase the use of single-cell RNA sequencing to infer cell-type compositional and cell-type-specific gene expression changes in intact bulk tissue and provide a foundation for investigating molecular mechanisms of retinal disease that lead to new therapeutic targets.

7.
Nat Commun ; 12(1): 4219, 2021 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-34244505

RESUMO

Streptococcus pyogenes (Spy) Cas9 has potential as a component of gene therapeutics for incurable diseases. One of its limitations is its large size, which impedes its formulation and delivery in therapeutic applications. Smaller Cas9s are an alternative, but lack robust activity or specificity and frequently recognize longer PAMs. Here, we investigated four uncharacterized, smaller Cas9s and found three employing a "GG" dinucleotide PAM similar to SpyCas9. Protein engineering generated synthetic RNA-guided nucleases (sRGNs) with editing efficiencies and specificities exceeding even SpyCas9 in vitro and in human cell lines on disease-relevant targets. sRGN mRNA lipid nanoparticles displayed manufacturing advantages and high in vivo editing efficiency in the mouse liver. Finally, sRGNs, but not SpyCas9, could be packaged into all-in-one AAV particles with a gRNA and effected robust in vivo editing of non-human primate (NHP) retina photoreceptors. Human gene therapy efforts are expected to benefit from these improved alternatives to existing CRISPR nucleases.


Assuntos
Proteína 9 Associada à CRISPR/genética , Sistemas CRISPR-Cas/genética , Edição de Genes/métodos , RNA Guia/genética , Staphylococcus/enzimologia , Animais , Proteína 9 Associada à CRISPR/isolamento & purificação , Linhagem Celular Tumoral , Modelos Animais de Doenças , Terapia Genética/métodos , Vetores Genéticos/administração & dosagem , Vetores Genéticos/genética , Células HEK293 , Humanos , Macaca fascicularis , Masculino , Camundongos , Parvovirinae/genética , Engenharia de Proteínas , Ribonucleases , Staphylococcus/genética , Especificidade por Substrato , Síndromes de Usher/genética , Síndromes de Usher/terapia
8.
Inorg Chem ; 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34289301

RESUMO

Introducing stereochemically active lone-pair Sb3+ cations into sulfates, two three-dimensional (3D) antimony-sulfates, Sb4O5SO4 (1) and Sb4O(SO4)(OH)2 (2), were achieved under moderate hydrothermal conditions. Both structures are constructed by tetranuclear-{Sb4}-clusters-based layers and SO4 tetrahedra. However, owing to the different packing patterns of the layers, they display different characteristics: 1 exhibits a centrosymmetric structure while 2 possesses a noncentrosymmetric structure. UV-vis spectra show that they possess wide band gaps. Sb4O(SO4)(OH)2 is nonlinear optical (NLO) active with a second-harmonic generation (SHG) response of ∼1.2 times of KH2PO4, together with the phase-matchable capacity, endowing it a promising UV NLO material. The first-principle calculations were performed to elucidate the structure-property relationships. The results indicate that the lone pair stereoactivity of Sb3+ provides the large contribution to the macroscopic SHG effect.

9.
Front Public Health ; 9: 691746, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34277551

RESUMO

This study empirically analysed the contagion of health using data from China Family Panel Studies. We first controlled variables related to health behaviour, medical conditions, individual characteristics, household characteristics, group characteristics, and prefecture/county characteristics and then employed multiple methods for estimation. The estimates showed that the average health level of others in the community had a significant positive effect on individual self-rated health-health was contagious. The measurement results remained robust after the endogeneity of the core explanatory variables was controlled using two-stage least squares. Furthermore, by analysing the heterogeneity of health contagion, we found that the contagion effect of health varied with the level of medical care, household affiliation, gender, rural/urban areas, and age groups. The contagion effect of health was more pronounced in the elderly population and the rural areas of the central region, where the level of medical care is relatively low, whereas it did not differ significantly between genders. Finally, the learning or imitation mechanism and social interaction mechanism of health contagion were examined.


Assuntos
Nível de Saúde , População Rural , Idoso , China/epidemiologia , Características da Família , Feminino , Humanos , Masculino
10.
Nat Commun ; 12(1): 4438, 2021 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-34290238

RESUMO

Identification of intrinsic disorder in proteins relies in large part on computational predictors, which demands that their accuracy should be high. Since intrinsic disorder carries out a broad range of cellular functions, it is desirable to couple the disorder and disorder function predictions. We report a computational tool, flDPnn, that provides accurate, fast and comprehensive disorder and disorder function predictions from protein sequences. The recent Critical Assessment of protein Intrinsic Disorder prediction (CAID) experiment and results on other test datasets demonstrate that flDPnn offers accurate predictions of disorder, fully disordered proteins and four common disorder functions. These predictions are substantially better than the results of the existing disorder predictors and methods that predict functions of disorder. Ablation tests reveal that the high predictive performance stems from innovative ways used in flDPnn to derive sequence profiles and encode inputs. flDPnn's webserver is available at http://biomine.cs.vcu.edu/servers/flDPnn/.


Assuntos
Biologia Computacional/métodos , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/metabolismo , Aprendizado de Máquina , Ligação Proteica , Análise de Sequência de Proteína
11.
Biochemistry ; 60(26): 2071-2083, 2021 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-34156819

RESUMO

Xylan and cellulose are the two major constituents of numerous types of lignocellulose. The bifunctional enzyme that exhibits xylanase/cellulase activity has attracted a great deal of attention in biofuel production. Previously, a thermostable GH10 family enzyme (XynA) from Bacillus sp. KW1 was found to degrade both xylan and cellulose. To improve bifunctional activity on the basis of structure, we first determined the crystal structure of XynA at 2.3 Å. Via molecular docking and activity assays, we revealed that Gln250 and His252 were indispensable to bifunctionality, because they could interact with two conserved catalytic residues, Glu182 and Glu280, while bringing the substrate close to the activity pocket. Then we used a structure-based engineering strategy to improve xylanase/cellulase activity. Although no mutants with increased bifunctional activity were obtained after much screening, we found the answer in the N-terminal 36-amino acid truncation of XynA. The activities of XynA_ΔN36 toward beechwood xylan, wheat arabinoxylan, filter paper, and barley ß-glucan were significantly increased by 0.47-, 0.53-, 2.46-, and 1.04-fold, respectively. Furthermore, upon application, this truncation released more reducing sugars than the wild type in the degradation of pretreated corn stover and sugar cane bagasse. These results showed the detailed molecular mechanism of the GH10 family bifunctional endoxylanase/cellulase. The basis of these catalytic performances and the screened XynA_ΔN36 provide clues for the further use of XynA in industrial applications.

12.
Aging (Albany NY) ; 13(13): 17155-17176, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-34081626

RESUMO

Hypoxia contributes significantly to the development of chemoresistance of many malignancies including esophageal cancer (EC). Accumulating studies have indicated that long non-coding RNAs play important roles in chemotherapy resistance. Here, we identified a novel lncRNA-EMS/miR-758-3p/WTAP axis that was involved in hypoxia-mediated chemoresistance to cisplatin in human EC. Hypoxia induced the expressions of lncRNA EMS and WTAP, and reduced the expression of miR-758-3p in EC cell line ECA-109. In addition, the expressions of EMS and WTAP were required for the hypoxia-induced drug resistance to cisplatin in EC cells, while overexpression of miR-758-3p reversed such chemoresistance. The targeting relationships between EMS and miR-758-3p, as well as miR-758-3p and WTAP, were verified by luciferase-based reporter assays and multiple quantitative assays after gene overexpression/knockdown. Moreover, we found significant correlations between tumor expressions of these molecules. Notably, higher levels of EMS/WTAP, or lower levels of miR-758-3p in tumors predicted worse survivals of EC patients. Furthermore, in a xenograft mouse model, targeted knockdown of EMS and WTAP in ECA-109 cells markedly attenuated the resistance of tumors to cisplatin treatments. Our study uncovers a critical lncRNA-EMS/miR-758-3p/WTAP axis in regulating hypoxia-mediated drug resistance to cisplatin in EC.


Assuntos
Antineoplásicos/farmacologia , Proteínas de Ciclo Celular/genética , Cisplatino/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/genética , Hipóxia/complicações , MicroRNAs/genética , Fatores de Processamento de RNA/genética , RNA Longo não Codificante/genética , Animais , Biomarcadores Tumorais , Linhagem Celular Tumoral , Neoplasias Esofágicas/mortalidade , Feminino , Técnicas de Silenciamento de Genes , Humanos , Camundongos , Camundongos Nus , Valor Preditivo dos Testes , Análise de Sobrevida , Ensaios Antitumorais Modelo de Xenoenxerto
13.
Artigo em Inglês | MEDLINE | ID: mdl-34139674

RESUMO

Being a best-known prototype of phase-change materials, GeTe was reported to possess many high-pressure phases, whose structural evolution and superconductivity remain under debate for decades. Herein, we systematically investigated the pressure dependence of electrical transport and the structural evolution of the GeTe via in situ angle-dispersive synchrotron X-ray diffraction and resistance measurements up to 55 GPa. At room temperature, the structural phase transitions from the initial rhombohedral phase to the Fm 3m phase, and then to an orthorhombic Pnma phase, were observed at pressures of about 4 and 13.4 GPa, respectively. Furthermore, the metallization occurred at around 11 GPa, where the superconductivity could also be observed. With increasing pressure, the superconducting transition temperature increases monotonically from 5.7 to 6.4 K and then is independent of pressure above 23 GPa in the pure Pnma phase. These results provide insights into the pressure-dependent evolution of the structure and superconductivity in GeTe and have implications for the understanding of other IV-VI semiconductors at high pressure.

14.
Mol Plant ; 14(9): 1454-1471, 2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34022440

RESUMO

Although taste is an important aspect of fruit quality, an understanding of its genetic control remains elusive in apple and other fruit crops. In this study, we conducted genomic sequence analysis of 497 Malus accessions and revealed erosion of genetic diversity caused by apple breeding and possible independent domestication events of dessert and cider apples. Signatures of selection for fruit acidity and size, but not for fruit sugar content, were detected during the processes of both domestication and improvement. Furthermore, we found that single mutations in major genes affecting fruit taste, including Ma1, MdTDT, and MdSOT2, dramatically decrease malate, citrate, and sorbitol accumulation, respectively, and correspond to important domestication events. Interestingly, Ma1 was identified to have pleiotropic effects on both organic acid content and sugar:acid ratio, suggesting that it plays a vital role in determining fruit taste. Fruit taste is unlikely to have been negatively affected by linkage drag associated with selection for larger fruit that resulted from the pyramiding of multiple genes with minor effects on fruit size. Collectively, our study provides new insights into the genetic basis of fruit quality and its evolutionary roadmap during apple domestication, pinpointing several candidate genes for genetic manipulation of fruit taste in apple.

15.
Sci Rep ; 11(1): 9499, 2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33947948

RESUMO

Holotrichia oblita (Coleoptera: Scarabaeidae) and some other scarab beetles are the main soil-dwelling pests in China. Bacillus thuringiensis (Bt) and Beauveria bassiana (Bb) are entomopathogens that have been used as biocontrol agents of various pests. However, scarab larvae especially H. oblita exhibited strong adaptability to these pathogens. Compared to other scarabs, H. oblita could form a specific soil egg case (SEC) structure surrounding its eggs, and young larvae complete the initial development process inside this structure. In this study, we investigated the role of SEC structure and microorganisms from SEC and egg surface in pathogen adaptability. 16S rRNA gene analysis revealed low bacterial richness and high community unevenness in egg surface, with Proteobacteria, Firmicutes, Bacteroidetes and Fusobacteria dominating. In terms of OTUs composition analysis, the data show that the egg surface contains a large number of unique bacteria, indicating that the egg bacterial community may be derived from maternal transmission. Furthermore, we found that all culturable bacteria isolated from egg surface possessed antimicrobial activity against both Bt and Bb. The Pseudomonas bacteria with a significantly higher abundance in egg surface showed strong Bt- and Bb antagonistic ability. In conclusion, this study demonstrated a unique and antimicrobial bacterial community of H. oblita egg surface, which may contribute to its adaptability. Furthermore, the specific SEC structure surrounding the H. oblita eggs will provide a stable microenvironment for the eggs and egg surface bacteria, which probably provides more advantages for H. oblita adaptation ability.

16.
Nature ; 593(7859): 429-434, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-34012082

RESUMO

Gene-editing technologies, which include the CRISPR-Cas nucleases1-3 and CRISPR base editors4,5, have the potential to permanently modify disease-causing genes in patients6. The demonstration of durable editing in target organs of nonhuman primates is a key step before in vivo administration of gene editors to patients in clinical trials. Here we demonstrate that CRISPR base editors that are delivered in vivo using lipid nanoparticles can efficiently and precisely modify disease-related genes in living cynomolgus monkeys (Macaca fascicularis). We observed a near-complete knockdown of PCSK9 in the liver after a single infusion of lipid nanoparticles, with concomitant reductions in blood levels of PCSK9 and low-density lipoprotein cholesterol of approximately 90% and about 60%, respectively; all of these changes remained stable for at least 8 months after a single-dose treatment. In addition to supporting a 'once-and-done' approach to the reduction of low-density lipoprotein cholesterol and the treatment of atherosclerotic cardiovascular disease (the leading cause of death worldwide7), our results provide a proof-of-concept for how CRISPR base editors can be productively applied to make precise single-nucleotide changes in therapeutic target genes in the liver, and potentially in other organs.


Assuntos
Sistemas CRISPR-Cas , LDL-Colesterol/sangue , Edição de Genes , Modelos Animais , Pró-Proteína Convertase 9/genética , Adenina/metabolismo , Animais , Células Cultivadas , Feminino , Hepatócitos/metabolismo , Humanos , Fígado/enzimologia , Mutação com Perda de Função , Macaca fascicularis/sangue , Macaca fascicularis/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mutagênese Sítio-Dirigida , Pró-Proteína Convertase 9/sangue , Pró-Proteína Convertase 9/metabolismo , Fatores de Tempo
17.
Genome Res ; 31(10): 1753-1766, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34035047

RESUMO

Recent developments of single-cell RNA-seq (scRNA-seq) technologies have led to enormous biological discoveries. As the scale of scRNA-seq studies increases, a major challenge in analysis is batch effects, which are inevitable in studies involving human tissues. Most existing methods remove batch effects in a low-dimensional embedding space. Although useful for clustering, batch effects are still present in the gene expression space, leaving downstream gene-level analysis susceptible to batch effects. Recent studies have shown that batch effect correction in the gene expression space is much harder than in the embedding space. Methods such as Seurat 3.0 rely on the mutual nearest neighbor (MNN) approach to remove batch effects in gene expression, but MNN can only analyze two batches at a time, and it becomes computationally infeasible when the number of batches is large. Here, we present CarDEC, a joint deep learning model that simultaneously clusters and denoises scRNA-seq data while correcting batch effects both in the embedding and the gene expression space. Comprehensive evaluations spanning different species and tissues showed that CarDEC outperforms Scanorama, DCA + Combat, scVI, and MNN. With CarDEC denoising, non-highly variable genes offer as much signal for clustering as the highly variable genes (HVGs), suggesting that CarDEC substantially boosted information content in scRNA-seq. We also showed that trajectory analysis using CarDEC's denoised and batch-corrected expression as input revealed marker genes and transcription factors that are otherwise obscured in the presence of batch effects. CarDEC is computationally fast, making it a desirable tool for large-scale scRNA-seq studies.

18.
J Hazard Mater ; 417: 126048, 2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-33992004

RESUMO

MXenes are a unique family of two-dimensional (2D) transition metal carbides and/or nitrides, which have been proven useful for energy storage, water purification, and biomedical applications. Herein, a kind of heterojunction structure was designed by grafting highly conductive MXene (Ti3C2) on the graphene oxide (GO) nanosheets, which was confirmed by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectronic spectroscopy (XPS) and Raman results. Open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and salt spray measurements corroborated that inclusion of 0.5 wt% Ti3C2 or GO-Ti3C2 into epoxy zinc-rich coating (ZRC) effectively enhance the cathodic protection capability. Additionally, superior corrosion resistance was achieved by incorporation of GO-Ti3C2 into ZRC since GO-Ti3C2 in the coating improved the utilization rate of zinc particles and GO provided barrier protection for inhibiting the diffusion of corrosive agents. At the end of immersion, Rc value of ZRC/GO-Ti3C2 coating was 3.047 × 104 Ω·cm2, which was one order of magnitude higher than that of ZRC coating. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) measurements demonstrated that ZRC/GO-Ti3C2 coating exhibited lower speed of zinc particles oxidation and intact steel substrate. Hence, ZRC/GO-Ti3C2 coating exhibited the optimal corrosion resistance among the four kinds of coatings.

19.
Materials (Basel) ; 14(6)2021 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-33799404

RESUMO

A method of forming an Mg/Al intermetallic compound coating enriched with Mg17Al12 and Mg2Al3 was developed by heat treatment of electrodeposition Al coatings on Mg alloy at 350 °C. The composition of the Mg/Al intermetallic compounds could be tuned by changing the thickness of the Zn immersion layer. The morphology and composition of the Mg/Al intermetallic compound coatings were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and electron backscattered diffraction (EBSD). Nanomechanical properties were investigated via nano-hardness (nHV) and the elastic modulus (EIT), and the corrosion behavior was studied through hydrogen evolution and potentiodynamic (PD) polarization. The compact and uniform Al coating was electrodeposited on the Zn-immersed AZ91D substrate. After heat treatment, Mg2Al3 and Mg17Al12 phases formed, and as the thickness of the Zn layer increased from 0.2 to 1.8 µm, the ratio of Mg2Al3 and Mg17Al12 varied from 1:1 to 4:1. The nano-hardness increased to 2.4 ± 0.5 GPa and further improved to 3.5 ± 0.1 GPa. The Mg/Al intermetallic compound coating exhibited excellent corrosion resistance and had a prominent effect on the protection of the Mg alloy matrix. The control over the ratio of intermetallic compounds by varying the thickness of the Zn immersion layer can be an effective approach to achieve the optimal comprehensive performance. As the Zn immersion time was 4 min, the obtained intermetallic compounds had relatively excellent comprehensive properties.

20.
Nanotechnology ; 2021 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-33770773

RESUMO

Molybdenum oxycarbide (MoOC) is a single-phase compound, which can serve as a potential anode for lithium-ion batteries that integrating the merits of high specific capacity of MoO2 and high conductivity of Mo2C. Herein, a novel architecture with N,P co-doped carbon nanofibers and MoOC nanodots is constructed from a one-step phosphorization of MoOx/aniline organic-inorganic hybrid. Ultrafine MoOC nanodots are well confined by N,P co-doped carbon nanofibers, which ensures the fast Li+/electron transfer and good stability of structure under repeated charge/discharge processes. When this unique hybrid is employed as an anode material for lithium-ion batteries, promising Li+ storage properties are gained, in terms of high specific capacity, superb rate and long-term cycling performance. The remarkable capacitive contribution facilitates the fast Li+ uptake/release. This work may sheds light on the development of well-defined molybdenum-based anodes for advanced lithium-ion batteries.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...