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1.
Nat Commun ; 15(1): 2949, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38580645

RESUMO

Manipulating liquid flow over open solid substrate at nanoscale is important for printing, sensing, and energy devices. The predominant methods of liquid maneuvering usually involve complicated surface fabrications, while recent attempts employing external stimuli face difficulties in attaining nanoscale flow control. Here we report a largely unexplored ion beam induced film wetting (IBFW) technology for open surface nanofluidics. Local electrostatic forces, which are generated by the unique charging effect of Helium focused ion beam (HFIB), induce precursor film of ionic liquid and the disjoining pressure propels and stabilizes the nanofilm with desired patterns. The IBFW technique eliminates the complicated surface fabrication procedures to achieve nanoscale flow in a controllable and rewritable manner. By combining with electrochemical deposition, various solid materials with desired patterns can be produced.

2.
Insights Imaging ; 15(1): 77, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38499879

RESUMO

OBJECTIVE: To appraise the quality of guidelines on intravenous iodinated contrast media (ICM) use in patients with kidney disease, and to compare the recommendations among them. METHODS: We searched four literature databases, eight guideline libraries, and ten homepages of radiological societies to identify English and Chinese guidelines on intravenous ICM use in patients with kidney disease published between January 2018 and June 2023. The quality of the guidelines was assessed with the Scientific, Transparent, and Applicable Rankings (STAR) tool. RESULTS: Ten guidelines were included, with a median STAR score of 46.0 (range 28.5-61.5). The guidelines performed well in "Recommendations" domain (31/40, 78%), while poor in "Registry" (0/20, 0%) and "Protocol" domains (0/20, 0%). Nine guidelines recommended estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m2 as the cutoff for referring patients to discuss the risk-benefit balance of ICM administration. Three guidelines further suggested that patients with an eGFR < 45 mL/min/1.73 m2 and high-risk factors also need referring. Variable recommendations were seen in the acceptable time interval between renal function test and ICM administration, and that between scan and repeated scan. Nine guidelines recommended to use iso-osmolar or low-osmolar ICM, while no consensus has been reached for the dosing of ICM. Nine guidelines supported hydration after ICM use, but their protocols varied. Drugs or blood purification therapy were not recommended as preventative means. CONCLUSION: Guidelines on intravenous ICM use in patients with kidney disease have heterogeneous quality. The scientific societies may consider joint statements on controversial recommendations for variable timing and protocols. CRITICAL RELEVANCE STATEMENT: The heterogeneous quality of guidelines, and their controversial recommendations, leave gaps in workflow timing, dosing, and post-administration hydration protocols of contrast-enhanced CT scans for patients with kidney diseases, calling for more evidence to establish a safer and more practicable workflow. KEY POINTS: • Guidelines concerning iodinated contrast media use in kidney disease patients vary. • Controversy remains in workflow timing, contrast dosing, and post-administration hydration protocols. • Investigations are encouraged to establish a safer iodinated contrast media use workflow.

3.
BMC Nurs ; 23(1): 54, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38238706

RESUMO

BACKGROUND: China is experiencing an aging population, leading to a significant demand for "Internet + nursing services" tailored for elderly individuals. However, there are many risk problems in the process of nurse service, which hinder the development of the service, and a scale is needed to assess the risk problems faced by nurses in "Internet + nursing services" for the elderly. OBJECTIVE: The purpose of this study is to develop an assessment scale for risk factors and outcomes related to nurses' involvement in the "Internet + Nursing Service" for the elderly and to assess its reliability and validity. METHODS: Based on literature analysis, focus group, the Delphi method, and a presurvey, we designed an initial scale. The initial scale comprised two sections: risk factors and risk outcomes for nurses. In January and February of 2023, nurses engaged in "Internet + nursing services" for the elderly in Shanxi Province were chosen through a convenience sampling technique for a questionnaire survey. Subsequently, item analysis and exploratory factor analysis were employed to refine and develop a test version of the scale further. A follow-up questionnaire survey was carried out in March and April 2023 using a similar approach. The reliability and validity of the scale were assessed through confirmatory factor analysis, culminating in the formation of the final scale. RESULTS: The initial survey yielded 244 valid responses. The cumulative variance contributions of the two segments from the exploratory factor analysis were 84.584% and 90.089%, respectively. A subsequent survey garnered 220 valid responses. The confirmatory factor analysis results indicated: χ2/df = 2.086, comparative fit index (CFI) = 0.918, normative fit index (NLI) = 0.855, root mean square of residuals (RMR) = 0.045, and root mean square of error of approximation (RMSEA) = 0.070. These results demonstrate good structural, convergent, and discriminant validity. The content validity index at the item level (I-CVI) ranged between 0.875 and 1.000, while the content validity index at the scale level (S-CVI/Ave) was 0.941. Cronbach's alpha coefficient for the entire scale stood at 0.970. Moreover, the scale exhibited a split-half reliability of 0.876 and a retest reliability of 0.980 (p < 0.01). CONCLUSION: The risk factors and risk outcomes associated with nurses involved in "Internet + nursing services" for elderly individuals, as developed in this study, demonstrate strong reliability and validity. They are well suited to the Chinese national context.

4.
Front Microbiol ; 14: 1250330, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37799601

RESUMO

Acidithiobacillus caldus plays an important role in bioleaching of low-grade metal ore. It can promote the release of heavy metals in mining-associated habitats and survive in high concentrations of heavy metals. Functions of glutathione reductase (GR) in cell defense against reactive oxygen species caused by heavy metals have been elucidated in some eukaryotic cells and bacteria; however, no information is available in A. caldus. In this research, the methods of bioinformatics, gene expression, GR activity assays were used to detect and characterize the glutathione reductase gene from the A. caldus MTH-04 strain. Then, A. caldus gr knockout mutant and gr overexpression strain were constructed, and the heavy metal tolerant properties and transcriptional levels of ROS related genes of them were compared to study the function of GR. The results showed that, a putative gr gene F0726_RS04210 was detected in the genome of A. caldus MTH-04. The purified recombinant protein of F0726_RS04210 showed remarkable GR activity at optimal pH 7.0 and 30°C using in vitro assay. The evolutionary relationship of GR from A. caldus MTH-04 was close to that from Escherichia coli K12. Gene knockout or overexpression of gr in A. caldus did not affect the growth rate on S0 medium, suggesting that GR did not play a key role in the activation of sulfur. Deletion of gr resulted in increased sensitivity to heavy metals (Cu2+ and Zn2+) in A. caldus, and the gr overexpression strain showed enhanced tolerance to heavy metals. Furthermore, transcription analysis also revealed strong correlations between GR and the antioxidant pathway. The above results suggest that GR can play an important role in heavy metal tolerance in A. caldus.

5.
Plant Dis ; 107(10): 3037-3050, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36890126

RESUMO

Among the most damaging diseases of rubber trees is anthracnose caused by the genus Colletotrichum, which leads to significant economic losses. Nonetheless, the specific Colletotrichum spp. that infect rubber trees in Yunnan Province, an important natural rubber base in China, have not been extensively investigated. Here, we isolated 118 Colletotrichum strains from rubber tree leaves exhibiting anthracnose symptoms in multiple plantations in Yunnan. Based on comparisons of their phenotypic characteristics and internal transcribed spacer ribosomal DNA sequences, 80 representative strains were chosen for additional phylogenetic analysis based on eight loci (act, ApMat, cal, CHS-1, GAPDH, GS, his3, and tub2), and nine species were identified. Colletotrichum fructicola, C. siamense, and C. wanningense were found to be the dominant pathogens causing rubber tree anthracnose in Yunnan. C. karstii was common, whereas C. bannaense, C. brevisporum, C. jinpingense, C. mengdingense, and C. plurivorum were rare. Among these nine species, C. brevisporum and C. plurivorum are reported for the first time in China, and two species are new to the world: C. mengdingense sp. nov. in the C. acutatum species complex and C. jinpingense sp. nov. in the C. gloeosporioides species complex. Their pathogenicity was confirmed with Koch's postulates by inoculating each species in vivo on rubber tree leaves. This study clarifies the geographic distribution of Colletotrichum spp. associated with anthracnose on rubber trees in representative locations of Yunnan, which is crucial for the implementation of quarantine measures.


Assuntos
Colletotrichum , Hevea , Hevea/genética , China , Filogenia , Doenças das Plantas , DNA Fúngico/genética , DNA Intergênico
6.
Ann Transl Med ; 10(18): 987, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36267745

RESUMO

Background: The use of vonoprazan (VPZ) has improved the Helicobacter pylori (H. pylori) eradication therapy in Japan. There is no agreement on the dosage and frequency of amoxicillin administration in the VPZ dual treatment in China. We aimed to investigate the clinical effectiveness and safety of 3 treatment regimens using VPZ as an acid-suppressing medication to eradicate H. pylori. Methods: This experiment involved an open, multicenter, randomized, and parallel controlled clinical investigation. A total of 230 newly diagnosed H. pylori-infected patients were then randomly assigned to 1 of 3 groups: (I) H-VA (high-dose amoxicillin combined with VPZ): VPZ 20 mg b.i.d with amoxicillin 750 mg q.i.d for 7 days; (II) L-VA (low-dose amoxicillin combined with VPZ): VPZ 20 mg b.i.d plus amoxicillin 500 mg q.i.d for 7 days; (III) VAC (amoxicillin combined with VPZ and clarithromycin): VPZ 20 mg b.i.d plus amoxicillin 750 mg plus clarithromycin 500 mg for 7 days. At least 4 weeks after treatment, the urea breath test (UBT) was reexamined. The effectiveness of various regimens was assessed based on compliance, safety, and eradication rate. Results: The regimen effectiveness was 63.5% (54/85) in the H-VA group, 58.3% (49/84) in the L-VA group, and 60.7% (37/61) in the VAC group, according to intention to treat (ITT) analysis. According to per protocol (PP) analysis, the eradication rate of the H-VA group was 65.1% (54/83), that of the L-VA group was 66.2% (49/74), and that of the VAC group was 64.9% (37/57). There was no discernible difference in the eradication rate across the 3 regimens, as shown by the results of ITT analysis (χ2=0.032, P=0.984) and PP analysis (χ2=0.480, P=0.786). The rate of adverse effect was 16.90% in the H-VA group, 13.20% in the L-VA group, and 24.10% in the VAC group. There was no discernible difference in the incidence of adverse effect between the three groups (χ2=2.784, P=0.266). Conclusions: None of the 7-day elimination regimens investigated in this study, which included the acid-suppressing medicine VPZ and either a dual treatment paired with amoxicillin, or a triple treatment combined with amoxicillin and clarithromycin, achieved an acceptable eradication rate of H. pylori. Further research is required to identify an effective and safe treatment regimen. Trial Registration: Chinese Clinical Trial Registry identifier: ChiCTR2000040955.

7.
Artigo em Inglês | MEDLINE | ID: mdl-36147642

RESUMO

Purpose: This study mainly analyzes the efficacy of 0.01% atropine eye drops (low-dose atropine (LDA)) combined with virtual reality (VR)-based binocular visual function (BVF) balance training in the prevention and control of juvenile myopia. Methods: One hundred and thirty-six juvenile myopia patients admitted between November 2018 to November 2021 were selected, including 76 cases (research group) receiving LDA + VR-based BVF balance training and 60 cases (control group) treated by LDA intervention alone. Visual acuity (VA; naked vision), ocular parameters (pupil diameter (PD), axial length (AXL), and diopter), intraocular pressure (IOP), accommodation facility, clinical efficacy, and incidence of adverse reactions were observed, compared, and analyzed in both groups. Results: After analysis, it was found that the research group showed significantly higher naked vision and PD while statistically lower D after intervention than the corresponding preinterventional parameters than the control group. While AXL showed no statistical difference between the groups and within groups. The IOP also differed insignificantly between groups, but the post-treatment accommodation facility was better in the research group compared with the baseline (before treatment) and control group. In terms of curative effects, an obviously higher total effective rate was determined in the research group. In addition, the two groups showed no significant difference in the incidence of adverse reactions. Conclusions: LDA + VR-based BVF balance training deserves clinical popularization, as it can prevent and control myopia among teenagers, with better adjusting effects on eye function and certain safety.

8.
Nat Commun ; 13(1): 3238, 2022 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-35688829

RESUMO

Two-dimensional (2D) semiconductors, especially transition metal dichalcogenides (TMDs), have been envisioned as promising candidates in extending Moore's law. To achieve this, the controllable growth of wafer-scale TMDs single crystals or periodic single-crystal patterns are fundamental issues. Herein, we present a universal route for synthesizing arrays of unidirectionally orientated monolayer TMDs ribbons (e.g., MoS2, WS2, MoSe2, WSe2, MoSxSe2-x), by using the step edges of high-miller-index Au facets as templates. Density functional theory calculations regarding the growth kinetics of specific edges have been performed to reveal the morphological transition from triangular domains to patterned ribbons. More intriguingly, we find that, the uniformly aligned TMDs ribbons can merge into single-crystal films through a one-dimensional edge epitaxial growth mode. This work hereby puts forward an alternative pathway for the direct synthesis of inch-scale uniform monolayer TMDs single-crystals or patterned ribbons, which should promote their applications as channel materials in high-performance electronics or other fields.

9.
Cell Signal ; 93: 110270, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35108641

RESUMO

Chronic kidney disease (CKD) is an growing public health concern associated with high mortality rates. The occurrences of vascular calcification (VC) increase concordantly with the progression of CKD.With CKD, hyperphosphatemia promotes intermediate VC, a process that is further facilitated by vascular smooth muscle cells (VSMCs) initiating osteogenic transdifferentiation. The purpose of this study was to determine the involvement of CKAP4 in VC progression. Clinical investigations demonstrate that elevated blood CKAP4 and matrix metallopeptidase 2 (MMP2) levels are related with CKD in individuals. As an in vitro model, mouse VSMCs were extracted and treated with high levels of phosphates (2.5 mmol/L Pi). We also created an in vivo mice model of CKD induced by 5/6 nephrophrectomies and a high-protein diet (High Pi diet). The expression of CKAP4 and MMP2 in both in vitro and in vivo models was significantly higher in VSMCs and calcified aorta in both models. Additionally, in vitro tests indicated that CKAP4 modulates YAP phosphorylation. Simultaneous silencing of CKAP4 and calcium content assay revealed a significant reduction in the VSMCs and calcium content of the aorta. Alizarin red staining and calcium content assay reveled that silencing of CKAP4 reduced the VSMCs and aortic calcification, accompanied with reduced expression of YAP and MMP2. Overall, our study demonstrates for the first time that CKAP4 contributes to VC in CKD by modulating YAP phosphorylation and MMP2 expression.


Assuntos
Insuficiência Renal Crônica , Calcificação Vascular , Animais , Cálcio/metabolismo , Feminino , Humanos , Masculino , Metaloproteinase 2 da Matriz/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Fosforilação , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/metabolismo , Calcificação Vascular/metabolismo
10.
Foods ; 11(3)2022 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-35159507

RESUMO

Gentiooligosaccharides (GnOS) are a kind of oligosaccharide formed by glucose with ß-1-6 glycosidic bonds, which has become a new type of functional oligosaccharide for its unique refreshing bitter taste and valuable probiotic effects. However, the research on the enzymatic preparation of GnOS is not thorough enough. In this study, a GH1 thermophilic ß-glucosidase from Thermotoga sp. KOL6 was used as a biocatalyst for the synthesis of GnOS. TsBgl1 exhibited excellent thermophilic and thermostable properties by possessing a melting temperature of 101.5 °C and reacting at 80-90 °C efficiently. Its half-life at 90 °C was approximately 5 h, suggesting its high heat resistance as well. TsBgl1 also showed excellent glucose tolerance with an inhibition constant (Ki) of 1720 mM and was stimulated in the presence of 0-900 mM glucose. TsBgl1 showed the highest hydrolytic activity on laminaribiose (Glc-ß-1,3-Glc), but mainly synthetized gentiobiose (Glc-ß-1,6-Glc) during transglycosylation. By optimizing the reaction conditions and substrate concentration, the highest yield of GnOS synthesized by TsBgl1 reached 144.3 g·L-1 when 1000 g·L-1 glucose was used as a substrate, which was higher than the highest yield ever reported. The thermophilic and thermostable properties of TsBgl1 were considered to be significant advantages in the industrial production of GnOS, where long periods of high-temperature reactions are required. This study was expected to provide an excellent candidate enzyme for industrial production of GnOS and also provide a reference for studying the transglycosylation of GH1 ß-glucosidases.

11.
Br J Pharmacol ; 179(1): 159-178, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34638162

RESUMO

BACKGROUND AND PURPOSE: Muscle protein catabolism in patients with diabetic nephropathy (DN) results in striking loss of muscle proteins, which increases morbidity and mortality risks. Evidence shows that short-chain fatty acids (SCFAs) play an important role in health maintenance and disease development. Recently, the connection between butyrate (a SCFA) and DN has been revealed, although the relationship between butyrate and muscle atrophy remains unclear. EXPERIMENTAL APPROACH: We studied changes in serum butyrate levels in DN patients using metabolomic analyses. In db/db mice, protective effects of butyrate on DN-induced muscle atrophy. were explored. Inhibition of muscle atrophy by butyrate and the underlying mechanism(s) were studied in C2C12 cells exposed to high glucose/lipopolysaccharide (HG/LPS). KEY RESULTS: Butyrate levels in DN patients were significantly decreased. In db/db mice, supplementing normal diet with butyrate improved intestinal barrier function. Concurrently, butyrate alleviated muscle atrophy, promoted PI3K/Akt/mTOR signalling, and suppressed oxidative stress and autophagy in skeletal muscle of db/db mice, and in HG/LPS-exposed C2C12 cells. Further, FFA2 receptors, key components of SCFA signalling, were decreased in skeletal muscle of db/db mice and in HG/LPS-exposed C2C12 cells. Overexpression of FFA2 receptors activated PI3K/Akt/mTOR signalling and inhibited oxidative stress and autophagy in HG/LPS-exposed C2C12 cells. Silencing of FFA2 blocked PI3K/Akt/mTOR signalling that was improved by butyrate, as well as the suppression of oxidative stress and reduction of autophagy. CONCLUSION AND IMPLICATION: Butyrate exerts protective effects on muscle atrophy induced by DN by enhancing intestinal barrier function and activating the FFA2 receptor-mediated PI3K/Akt/mTOR pathway.


Assuntos
Diabetes Mellitus , Nefropatias Diabéticas , Animais , Butiratos/farmacologia , Butiratos/uso terapêutico , Nefropatias Diabéticas/tratamento farmacológico , Nefropatias Diabéticas/metabolismo , Humanos , Camundongos , Músculo Esquelético/metabolismo , Atrofia Muscular/tratamento farmacológico , Atrofia Muscular/prevenção & controle , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Serina-Treonina Quinases TOR/metabolismo
12.
ACS Nano ; 15(10): 16760-16768, 2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34549939

RESUMO

Van der Waals heterostructures composed of different two-dimensional films offer a unique platform for engineering and promoting photoelectric performances, which highly demands the understanding of photocarrier dynamics. Herein, large-scale vertically stacked heterostructures with MoS2 and ReSe2 monolayers are fabricated. Correspondingly, the carrier dynamics have been thoroughly investigated using different ultrafast spectroscopies, including Terahertz (THz) emission spectroscopy, time-resolved THz spectroscopy (TRTS), and near-infrared optical pump-probe spectroscopy (OPPS), providing complementary dynamic information for the out-of-plane charge separation and in-plane charge transport at different stages. The initial charge transfer (CT) within the first 170 fs, generating a transient directional current, is directly demonstrated by the THz emissions. Furthermore, the TRTS explicitly unveils an intermediate free-carrier relaxation pathway, featuring a pronounced augmentation of THz photoconductivity compared to the isolated ReSe2 layer, which likely contains the evolution from immigrant hot charged free carriers to bounded interlayer excitons (∼0.7 ps) and the surface defect trapping (∼13 ps). In addition, the OPPS reveals a distinct enhancement in the saturable absorption along with long-lived dynamics (∼365 ps), which originated from the CT and interlayer exciton recombination. Our work provides comprehensive insight into the photocarrier dynamics across the charge separation and will help with the development of optoelectronic devices based on ReSe2-MoS2 heterostructures.

13.
Oncogene ; 40(8): 1458-1475, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33420370

RESUMO

Procollagen lysyl hydroxylase 1 (PLOD1) is highly expressed in malignant tumors such as esophageal squamous cell carcinoma, gastric cancer, and colorectal cancer. Bioinformatics analysis revealed that PLOD1 is associated with the progression of GBM, particularly the most malignant mesenchymal subtype (MES). Moreover, in the TCGA and CGGA datasets, the mean survival time of patients with high PLOD1 expression was significantly shorter than that of patients with low expression. The clinical samples confirmed this result. Therefore, we aimed to investigate the effect of PLOD1 on the development of mesenchymal GBM in vitro and in vivo and its possible mechanisms. Molecular experiments were conducted on the patient-derived glioma stem cells and found that PLOD1 expressed higher in tumor tissues and cancer cell lines of patients with GBM, especially in the MES. PLOD1 also enhanced tumor viability, proliferation, migration, and promoted MES transition while inhibited apoptosis. Tumor xenograft results also indicated that PLOD1 overexpression significantly promotes malignant behavior of tumors. Mechanistically, bioinformatics analysis further revealed that PLOD1 expression was closely associated with the NF-κB signaling pathway. Besides, we also found that hypoxic environments also enhanced the tumor-promoting effects of PLOD1. In conclusion, overexpression of PLOD1 may be an important factor in the enhanced invasiveness and MES transition of GBM. Thus, PLOD1 is a potential treatment target for mesenchymal GBM or even all GBM.


Assuntos
Glioblastoma/genética , Pró-Colágeno-Lisina 2-Oxoglutarato 5-Dioxigenase/genética , Fator de Transcrição RelA/genética , Hipóxia Tumoral/genética , Animais , Apoptose/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Bases de Dados Factuais , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Glioblastoma/patologia , Humanos , Estimativa de Kaplan-Meier , Masculino , NF-kappa B/genética , Fenótipo , Transdução de Sinais/genética
14.
Nanotechnology ; 32(9): 095601, 2021 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-33113522

RESUMO

Two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) are promising platforms for developing next-generation electronic and optoelectronic devices due to their unique properties. To achieve this, the growth of large single-crystal TMDs is a critical issue. Unraveling the factors affecting the nucleation and domain orientation should hold fundamental significance. Herein, we design the chemical vapor deposition growth of monolayer MoS2 triangles on Au(111) and Au(100) facets, for exploring the substrate facet effects on the domain orientations. According to multi-scale characterizations, we find that, the obtained triangular MoS2 domains present two preferential orientations on the six-fold symmetric Au(111) facet, whereas four predominant orientations on the four-fold symmetric Au(100) facet. Using on-site scanning tunneling microscopy, we further reveal the preferred alignments of monolayer MoS2 triangles along the close-packed directions of both Au(111) and Au(100) facets. Moreover, bunched substrate steps are also found to form along the close-packed directions of the crystal facets, which guides the preferential nucleation of monolayer MoS2 along the step edges. This work should hereby deepen the understanding of the substrate facet/step effect on the nucleation and orientation of monolayer MoS2 domains, thus providing fundamental insights into the controllable syntheses of large single-crystal TMD monolayers.

15.
ACS Nano ; 14(8): 10527-10535, 2020 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-32790282

RESUMO

We propose a technique of Raman spectroscopy to characterize the excitonic nature and to evaluate the relative contribution of the two kinds of electron/exciton-phonon interactions that are observed in two-dimensional transition-metal dichalcogenides (TMDCs). In the TMDCs, the electron/exciton-phonon interactions mainly originate from the deformation potential (DP) or the Fröhlich interaction (FI) which give the mutually different Raman tensors. Using a circularly polarized light, the relative proportion of the DP and the FI can be defined by the ratio of helicity-polarized intensity that is observed by MoS2. By this analysis, we show that the excitonic FI interaction gradually increases with decreasing temperature, contributes equally to DP at ∼230 K, and dominates at lower temperatures. The excitonic effect in the Raman spectra is confirmed by modulating the dielectric environment for the exciton and by changing the laser power.

16.
ACS Nano ; 14(4): 5036-5045, 2020 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-32267670

RESUMO

Two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) have emerged as attractive platforms in next-generation nanoelectronics and optoelectronics for reducing device sizes down to a 10 nm scale. To achieve this, the controlled synthesis of wafer-scale single-crystal TMDs with high crystallinity has been a continuous pursuit. However, previous efforts to epitaxially grow TMD films on insulating substrates (e.g., mica and sapphire) failed to eliminate the evolution of antiparallel domains and twin boundaries, leading to the formation of polycrystalline films. Herein, we report the epitaxial growth of wafer-scale single-crystal MoS2 monolayers on vicinal Au(111) thin films, as obtained by melting and resolidifying commercial Au foils. The unidirectional alignment and seamless stitching of the MoS2 domains were comprehensively demonstrated using atomic- to centimeter-scale characterization techniques. By utilizing onsite scanning tunneling microscope characterizations combined with first-principles calculations, it was revealed that the nucleation of MoS2 monolayer is dominantly guided by the steps on Au(111), which leads to highly oriented growth of MoS2 along the ⟨110⟩ step edges. This work, thereby, makes a significant step toward the practical applications of MoS2 monolayers and the large-scale integration of 2D electronics.

17.
ACS Appl Mater Interfaces ; 11(51): 48221-48229, 2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31782301

RESUMO

Vertical heterostructures formed by stacks of two-dimensional (2D) layered materials with disparate electronic properties have attracted tremendous attention for their versatile applications. The targeted fabrication of such vertical stacks with clean interfaces and a specific stacking sequence remains challenging. Herein, we design a two-step chemical vapor deposition route for the direct synthesis of unconventional graphene/PtSe2 vertical stacks (Gr/PtSe2) on conductive Au foil substrates. Monolayer PtSe2 (1L-PtSe2) was detected to preferentially grow at the interface of the predeposited Gr layer and the Au foil substrate rather than on the Gr surface. The concurrent effect from the strong interaction of PtSe2/Au and the space confinement effect of Gr/Au are proposed to be the essential mechanisms. Particularly, this unique growth system allows us to uncover the intrinsic property of 1L-PtSe2 and the interfacial coupling effect using scanning tunneling microscopy/spectroscopy. Our work should hereby enable significant advances in the synthesis of 2D-based vertical heterostructures and in the exploration of their intrinsic interface properties.

18.
Small ; 15(45): e1902789, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31544354

RESUMO

Palladium diselenide (PdSe2 ) is an emerging 2D layered material with anisotropic optical/electrical properties, extra-high carrier mobility, excellent air stability, etc. So far, ultrathin PdSe2 is mainly achieved via mechanical exfoliation from its bulk counterpart, and the direct synthesis is still challenging. Herein, the synthesis of ultrathin 2D PdSe2 on conductive Au foil substrates via a facile chemical vapor deposition route is reported. Intriguingly, an anisotropic growth behavior is detected from the evolution of ribboned flakes with large length/width ratios, which is well explained from the orthorhombic symmetry of PdSe2 . A unique even-layered growth mode from 2 to 20 layers is also confirmed by the perfect combination of onsite scanning tunneling microscopy characterizations, through deliberately scratching the flake edge to expose both even and odd layers. This even-layered, ribboned 2D material is expected to serve as a perfect platform for exploring unique physical properties, and for developing high-performance electronic and optoelectronic devices.

19.
J Am Chem Soc ; 141(47): 18694-18703, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31558019

RESUMO

Two-dimensional (2D) metallic transition metal dichalcogenides (MTMDCs) have attracted tremendous interest due to their intriguing physical properties and broad application potential. However, batch production of high-quality 2D MTMDCs based on existing synthesis on 2D surfaces remains a huge challenge. Herein, a universal synthetic route for the scalable synthesis of high-quality 2D MTMDC (e.g., TaS2, V5S8, and NbS2) nanosheets using microcrystalline NaCl crystals as templates via a facile chemical vapor deposition method is reported. Obviously, this synthetic route is perfectly compatible with a facile water dissolution-filtration process for obtaining high-purity MTMDC nanosheet powders. Representatively, a thickness-uniform 1T-TaS2 nanosheet product can be achieved that shows unexceptionable dispersibility in ethanol, which allows its assembly onto arbitrary substrates/electrodes for high-performance energy-related applications, herein serving as a high-performance electrocatalyst for the hydrogen evolution reaction. This work sheds light on the batch production, green transfer, and energy-related application of 2D MTMDC materials.

20.
Acta Biochim Biophys Sin (Shanghai) ; 51(10): 997-1007, 2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31518383

RESUMO

Pancreatic cancer (PC) is the seventh most frequent cause of cancer-related deaths worldwide with a high mortality. MicroRNAs (miRNAs) act as important regulators for the development of PC and participate in the progression of PC. miR-129-5p was reported to regulate the progression of tumors, such as thyroid cancer and gastric cancer. However, the function of miR-129-5p in PC is still unclear. In this study, the down-regulation of miR-129-5p was detected in PC tissues and PC cells. miR-129-5p was overexpressed or knocked down in AsPC-1 and BxPC-3 cells. The results showed that miR-129-5p overexpression suppressed proliferation, migration and invasion, and induced apoptosis of PC cells, whereas miR-129-5p knockdown showed opposite effects. In addition, we found that pre-B-cell leukemia homeobox 3 (PBX3) overexpression promoted proliferation, migration and invasion, but reduced apoptosis of PC cells. PBX3 was identified as a target of miR-129-5p by informatics analysis and dual luciferase reporter assay. Finally, our results indicated that miR-129-5p suppressed cell proliferation and migration by targeting PBX3. This study demonstrated that miR-129-5p could function as a tumor suppressor in the progression and development of PC by targeting PBX3, providing a reliable prognostic factor and a new therapeutic strategy for PC.


Assuntos
Regulação Neoplásica da Expressão Gênica , Proteínas de Homeodomínio/genética , MicroRNAs/genética , Neoplasias Pancreáticas/genética , Proteínas Proto-Oncogênicas/genética , Apoptose , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Neoplasias Pancreáticas/patologia
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