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1.
ACS Nano ; 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32031780

RESUMO

Wafer-scale monocrystalline two-dimensional (2D) materials can theoretically be grown by seamless coalescence of individual domains into a large single crystal. Here we present a concise study of the coalescence behavior of crystalline 2D films using a combination of complementary in situ methods. Direct observation of overlayer growth from the atomic to the millimeter scale and under model- and industrially relevant growth conditions reveals the influence of the film-substrate interaction on the crystallinity of the 2D film. In the case of weakly interacting substrates, the coalescence behavior is dictated by the inherent growth kinetics of the 2D film. It is shown that the merging of coaligned domains leads to a distinct modification of the growth dynamics through the formation of fast-growing high-energy edges. The latter can be traced down to a reduced kink-creation energy at the interface between well-aligned domains. In the case of strongly interacting substrates, the lattice mismatch between film and substrate induces a pronounced moiré corrugation that determines the growth and coalescence behavior. It furthermore imposes additional criteria for seamless coalescence and determines the structure of grain boundaries. The experimental findings, obtained here for the case of graphene, are confirmed by theory-based growth simulations and can be generalized to other 2D materials that show 3- or 6-fold symmetry. Based on the gained understanding of the relation between film-substrate interaction, shape evolution, and coalescence behavior, conditions for seamless coalescence and, thus, for the optimization of large-scale production of monocrystalline 2D materials are established.

2.
Biomed Pharmacother ; 125: 109703, 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32062551

RESUMO

High rate of glycolysis supports hepatocellular carcinoma (HCC) cell growth even in a hypoxic environment. However, the mechanism underlying glycolysis under hypoxia remains largely unknown. Long noncoding RNAs (lncRNAs) play essential roles in regulating glucose metabolism in cancers. This study aimed to explore the role of lncRNA homeobox transcript antisense RNA (HOTAIR) in HCC glycolysis under hypoxia. Thirty-eight HCC patients were recruited. HepG2 and Huh7 cells were used for study in vitro. The expression levels of HOTAIR, microRNA-130a-3p (miR-130a-3p) and hypoxia inducible factor 1 alpha (HIF1A) were measured by quantitative real-time polymerase chain reaction and western blot, respectively. The glycolysis under hypoxia (1 % O2) condition was investigated by glucose consumption, lactate production and hexokinase 2 (HK2) level. The target interaction between miR-130a-3p and HOTIR or HIF1A was analyzed by bioinformatics analysis, luciferase assay, RNA pull-down and RNA immunoprecipitation. We found that HOTAIR expression was enhanced in HCC tissues and cells. Under hypoxia condition, HOTAIR expression was increased and its knockdown inhibited glycolysis in HCC cells. HOTAIR was validated as a decoy of miR-130a-3p and miR-130a-3p deficiency reversed the suppressive effect of HOTAIR silence on glycolysis under hypoxia. HIF1A was indicated as a target of miR-130a-3p and miR-130a-3p overexpression repressed glycolysis under hypoxia by targeting HIF1A. Moreover, HIF1A expression was regulated by HOTAIR and miR-130a-3p. In conclusion, knockdown of HOTAIR suppressed glycolysis by regulating miR-130a-3p and HIF1A in HCC cells treated by hypoxia, elucidating a novel mechanism in HCC glycolysis.

3.
Sensors (Basel) ; 20(3)2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-32012671

RESUMO

A digital closed-loop system design of a microelectromechanical systems (MEMS) disk resonator gyroscope (DRG) is proposed in this paper. Vibration models with non-ideal factors are provided based on the structure characteristics and operation mode of the sensing element. The DRG operates in force balance mode with four control loops. A closed self-excited loop realizes stable vibration amplitude on the basis of peak detection technology and phase control loop. Force-to-rebalance technology is employed for the closed sense loop. A high-frequency carrier loaded on an anchor weakens the effect of parasitic capacitances coupling. The signal detected by the charge amplifier is demodulated and converted into a digital output for subsequent processing. Considering compatibility with digital circuits and output precision demands, a low passband sigma-delta (ΣΔ) analog-to-digital converter (ADC) is implemented with a 111.8dB signal-to-noise ratio (SNR). The analog front-end and digital closed self-excited loop is manufactured with a standard 0.35 µm complementary metal-oxide-semiconductor (CMOS) technology. The experimental results show a bias instability of 2.1 °/h and a nonlinearity of 0.035% over the ± 400° full-scale range.

4.
Chem Commun (Camb) ; 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32022085

RESUMO

A pre-synthetic strategy was developed for the construction of single ion conductive covalent organic frameworks (COFs). A high Li+ conductivity of 1.6 × 10-3 S cm-1 at 273 K was achieved, and single Na+ and K+ COFs were also obtained by using Na+ and K+ salts as monomers according to this synthetic method.

5.
J Nat Prod ; 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32003565

RESUMO

The phytochemical investigation of the roots of Croton crassifolius led to the isolation of 16 new halimane furanoditerpenoids, crohalifuranes A-P (1-16), along with 15 known analogues, 17-31. The new structures including their absolute configurations were elucidated by NMR and MS data analysis, comparison of experimental and calculated electronic circular dichroism data, single-crystal X-ray diffraction data, and chemical methods. Crohalifuranes A (1) and B (2) are tetranor- and 19-nor-halimane diterpenoids featuring a rare decahydroacenaphthene core, respectively, which might be derived from the accompanying crassifoliusin A by loss of the furan ring or the C-19 substituent. Crohalifurane C (3) represents the first example of a 20-nor-halimane diterpenoid, and crohalifurane D (4) is characterized by an unusual 6,20-δ-lactone moiety. All compounds were examined for their inhibitory effects on nitric oxide (NO) production induced by lipopolysaccharide in RAW264.7 cells, and 2 and 23 exhibited moderate inhibition on NO production with IC50 values of 17.2 ± 1.3 and 23.7 ± 1.4 µM, respectively.

6.
J Cell Mol Med ; 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32052546

RESUMO

Lung cancer is the world's leading cause of cancer-related morbidity and mortality despite advances in surgery, chemotherapy and immunotherapy; thus, there is an urgent need to find new molecules to develop novel treatment strategies. Although ncRNAs were found to account for 98% transcripts, the number of lncRNAs with distinct function in lung cancer is extremely limited. We previously demonstrated that Plasmodium infection inhibits tumour growth and metastasis, but the exact mechanisms involved have not been fully understood. In this study, we carried out RNA sequencing (RNA-Seq) of tumour tissues isolated from LLC tumour-bearing mice treated with either Plasmodium yoelli (Py)-infected red blood cells or uninfected red blood cells. We found that F630028O10Rik (abbreviated as F63) is a novel lncRNA that was significantly up-regulated in tumours isolated from mice treated with Py-infected red blood cells compared to the control. By using gene silencing technique, F63 was found to inhibit both tumour Vascular Endothelial Growth Factor A (VEGFA) secretion and endothelial cells clone formation, migration, invasion and tube formation. Injection of cholesterol-modified siRNA-F63 into mice tumour tissues produced a significant increase in tumour volume, blood vessel formation and angiogenesis 17 days after injection. We further showed that inhibiting miR-223-3p results in the down-regulation of VEGFA and VEGFR2 which are vital molecules for angiogenesis. These results reveal that F63 inhibit tumour growth and progression by modulating tumour angiogenesis suggesting F63 can be a novel lncRNA with great potential as a candidate molecule for gene therapy in lung cancer.

7.
Expert Opin Drug Deliv ; : 1-15, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32009483

RESUMO

Background: Natamycin is the only topical ophthalmic antifungal drug approved by the Food and Drug Administration (FDA) of the United States, but has unsatisfactory factors such as high dosing frequency.Methods: We report the synthesis and preparation of self-assembled poly(ethylene glycol)-block-poly(glycidyl methacrylate) (PEG-b-PGMA) micelles. These nanoparticles exhibit sustained delivery of a hydrophobic natamycin by topical administration on eye due to the hydrolysable properties of PGMA segments of micelle. Hydrolysis of glycidyl groups within a physiologically relevant environment provides an additional driving force for drug release by generation of hydrophilic hydroxyl groups to 'push' the encapsulated hydrophobic drug away from the resultant hydrophilic domains and into surrounding environment.Results: In vitro and in vivo results revealed that the self-assembled micelles and the encapsulated natamycin were not cytotoxic and the released drug have strong antifungal ability to Candida albicans. Importantly, sustained natamycin release from micelles leads to the reduced administration frequency of natamycin from 8 times per day to 3 times per day in rabbits suffering from fungal keratitis (FK).Conclusion: This study demonstrates a facile method that can greatly reduce dosing frequency of natamycin administration and thus improve long-term patient compliance.

8.
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.

9.
Mar Biotechnol (NY) ; 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31974738

RESUMO

The original version of this article unfortunately contained a mistake in the authorgroup section. Author Zhenmin Bao's given name was incorrectly spelled as "Zhemin Bao".

10.
Ultramicroscopy ; 210: 112929, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31935670
11.
Adv Mater ; : e1906939, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31945238

RESUMO

Polymer-based thermal management materials have many irreplaceable advantages not found in metals or ceramics, such as easy processing, low density, and excellent flexibility. However, their limited thermal conductivity and unsatisfactory resistance to elevated temperatures (<200 °C) still prevent effective heat dissipation during applications with high-temperature conditions or powerful operation. Therefore, herein highly thermoconductive and thermostable polymer nanocomposite films prepared by engineering 1D aramid nanofiber (ANF) with worm-like microscopic morphologies into rigid rod-like structures with 2D boron nitride nanosheets (BNNS) are reported. With no coils or entanglements, the rigid polymer chain enables a well-packed crystalline structure resulting in a 20-fold (or greater) increase in axial thermal conductivity. Additionally, strong interfacial interactions between the weaved ANF rod and the stacked BNNS facilitate efficient heat flux through the 1D/2D configuration. Hence, unprecedented in-plane thermal conductivities as high as 46.7 W m-1 K-1 can be achieved at only 30 wt% BNNS loading, a value of 137% greater than that of a worm-like ANF/BNNS counterpart. Moreover, the thermally stable nanocomposite films with light weight (28.9 W m-1 K-1 /103 (kg m-3 )) and high strength (>100 MPa, 450 °C) enable effective thermal management for microelectrodes operating at temperatures beyond 200 °C.

12.
Zool Res ; : 1-9, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31945810

RESUMO

The accessory olfactory bulb (AOB), located at the posterior dorsal aspect of the main olfactory bulb (MOB), is the first brain relay of the accessory olfactory system (AOS), which can parallelly detect and process volatile and nonvolatile social chemosignals and mediate different sexual and social behaviors with the main olfactory system (MOS). However, due to its anatomical location and absence of specific markers, there is a lack of research on the internal and external neural circuits of the AOB. This issue was addressed by single-color labeling and fluorescent double labeling using retrograde rAAVs injected into the bed nucleus of the stria terminalis (BST), anterior cortical amygdalar area (ACo), medial amygdaloid nucleus (MeA), and posteromedial cortical amygdaloid area (PMCo) in mice. We demonstrated the effectiveness of this AOB projection neuron labeling method and showed that the mitral cells of the AOB exhibited efferent projection dispersion characteristics similar to those of the MOB. Moreover, there were significant differences in the number of neurons projected to different brain regions, which indicated that each mitral cell in the AOB could project to a different number of neurons in different cortices. These results provide a circuitry basis to help understand the mechanism by which pheromone information is encoded and decoded in the AOS.

13.
Artigo em Inglês | MEDLINE | ID: mdl-31995363

RESUMO

Dynamic tuning of terahertz (THz) wave has a great potential application as smart THz devices, such as switches, modulators, sensors, and so on. However, the realization of flexible THz modulation with high efficiency is rarely observed, which is nearly absent from the booming development and demands on flexible electronics. Here, we report a flexible THz modulation based on conductive polymer composites composed of thermoplastic polyurethane (TPU) and conductive particles (Ni). By designing the additive content of Ni particles, such a flexible layer exhibits resistivity change of 6-7 orders under tensile strain due to the formation of an electron-transport channel provided by the in situ evolution of the Ni network. It could be used to dynamically control the THz transmission with a giant modulation depth of around 96%, at a high strain operation (up to around 58.5%). Moreover, these characteristics are demonstrated to be available for highly tension sensitive THz spectroscopy and imaging. This work opens up a connection between flexible polymer-based composites and THz dynamic devices. It proposes an unprecedented flexible THz modulation with giant tuning efficiency and provides a scheme for contactless and passive tension sensors.

14.
J Cell Biochem ; 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31960989

RESUMO

Colorectal cancer (CRC), a fatal tumor, has been diagnosed as one of the most prevalent types of cancers globally, inducing multiple cancer-linked deaths. Mounting evidence has revealed that circular RNA (circRNA) elicits a regulatory impact on the initiation and development of cancers. Emerged as a new circRNA, hsa_circ_0000677 (circ-ABCC1) has not been studied in cancer progression. This study is the first attempt to explore the regulatory role of circ-ABCC1 in CRC. In this study, data from sphere-forming, transwell, and Western blot analyses revealed that cell stemness, sphere formation, and metastasis were notably enhanced in CD133+ cells isolated from CRC cells. In addition, exosomes from CD133+ cells could promote cell stemness, sphere formation, and metastasis. Moreover, circ-ABCC1 was verified to be characterized with a loop structure through quantitative reverse-transcription polymerase chain reaction analysis. Functional assays testified that the upregulation of circ-ABCC1 contributed to cell stemness, sphere formation, and metastasis in CD133- /Caco2 or CD133- /HCT15 cells. Furthermore, the interaction between circ-ABCC1 and ß-catenin was analyzed via RNA immunoprecipitation and RNA pull-down and finally, circ-ABCC1 was confirmed to facilitate CRC progression by activating the Wnt/ß-catenin pathway. To sum up, exosomes from CD133+ cells carrying circ-ABCC1 can mediate cell stemness and metastasis in CRC, unveiling that circ-ABCC1 serves as a novel candidate target for CRC treatment.

15.
Carbohydr Polym ; 230: 115613, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887935

RESUMO

Targeted and sensitive drug release at the colitis site is critical for the effective therapy of ulcerative colitis and reduction of side effects from the drug. Herein, we used 3,3'-dithiodipropionic acid (DTPA) to covalently link quercetin (Qu) and glyceryl caprylate-caprate (Gcc) via ester bonds to prepare Qu-SS-Gcc lipid nanoparticles (Qu-SS-Gcc LNPs). Dexamethasone (Dex) was used as a model drug, and chitosan (CSO) was modified on the surface of Qu-SS-Gcc LNPs to obtain CSO-modified Dex-loaded Qu-SS-Gcc LNPs (CSO/Dex/LNPs). The encapsulation efficiency and drug loading of CSO/Dex/LNPs were 93.1 % and 8.1 %, respectively. The in vitro release results showed that CSO/Dex/LNPs had esterase-responsive characteristics and could release the drug rapidly in esterase-containing artificial intestinal fluid. A human colorectal adenocarcinoma cell (Caco-2) monolayer was used as the intestinal cell barrier model. Transmembrane resistance measurements and permeation experiments showed that CSO/Dex/LNPs had a protective effect on the lipopolysaccharide (LPS)-stimulated Caco-2 cell monolayer and increased the expression of E-cadherin in LPS-stimulated Caco-2 cells. Moreover, CSO/Dex/LNPs could significantly reduce the expression of the inflammatory factors TNF-α, IL-6 and NO in LPS-stimulated RAW 264.7 cells. The ulcerative colitis mouse model was constructed by using C57BL/6 mice. The in vivo distribution results showed that CSO/Dex/LNPs had colon-targeting effects and strong retention ability in the colons of mice with colitis. The results also showed that CSO/Dex/LNPs had better anti-inflammatory effects than free Dex, which could reduce colonic atrophy, reduce histomorphological changes and increase the expression of E-cadherin in the colon. Furthermore, the expression levels of TNF-α, IL-6 and NO in the CSO/Dex/LNP-treated group were 37.4 %, 35.5 % and 33.2 % of those in mice with colitis, respectively.

16.
Viruses ; 12(1)2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31941083

RESUMO

The CRISPR/Cas system protects bacteria against bacteriophage and plasmids through a sophisticated mechanism where cas operon plays a crucial role consisting of cse1 and cas3. However, comprehensive studies on the regulation of cas3 operon of the Type I-E CRISPR/Cas system are scarce. Herein, we investigated the regulation of cas3 in Escherichia coli. The mutation in gcvP or crp reduced the CRISPR/Cas system interference ability and increased bacterial susceptibility to phage, when the casA operon of the CRISPR/Cas system was activated. The silence of the glycine cleavage system (GCS) encoded by gcvTHP operon reduced cas3 expression. Adding N5, N10-methylene tetrahydrofolate (N5, N10-mTHF), which is the product of GCS-catalyzed glycine, was able to activate cas3 expression. In addition, a cAMP receptor protein (CRP) encoded by crp activated cas3 expression via binding to the cas3 promoter in response to cAMP concentration. Since N5, N10-mTHF provides one-carbon unit for purine, we assumed GCS regulates cas3 through associating with CRP. It was evident that the mutation of gcvP failed to further reduce the cas3 expression with the crp deletion. These results illustrated a novel regulatory pathway which GCS and CRP co-regulate cas3 of the CRISPR/Cas system and contribute to the defence against invasive genetic elements, where CRP is indispensable for GCS regulation of cas3 expression.

17.
Artigo em Inglês | MEDLINE | ID: mdl-31965268

RESUMO

From a metabolic perspective, cancer may be considered as a metabolic disease characterized by reprogrammed glycolytic metabolism. The aim of the present study was to investigate CD147-mediated glucose metabolic regulation in hepatocellular carcinoma (HCC) and its contribution to altered immune responses in the tumor microenvironment. Several HCC cell lines and corresponding nude mice xenografts models differing in CD147 expressions were established to directly investigate the role of CD147 in the reprogramming of glucose metabolism, and to determine the underlying molecular mechanisms. Immunohistochemistry (IHC) analyses and flow cytometry were used to identify the relationship between reprogrammed glycolysis and immunosuppression in HCC. Upregulated CD147 expressions were found to be associated with enhanced expressions of GLUT1, MCT1 in HCC tumorous tissues. CD147 promoted the glycolytic metabolism in HCC cell lines in vitro via the PI3K/Akt/mTOR signaling pathway. A positive correlation existed between a profile of immunosuppressive lymphocytes infiltration and CD147 expression in HCC tissues. Accumulation of FOXP3-expressing regulatory T cells was induced under a stimulation with lactate in vitro. In conclusion, CD147 promoted glycolytic metabolism in HCC via the PI3K/Akt/mTOR signaling pathway, and was related to immunosuppression in HCC.

18.
Clin Nucl Med ; 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31977489

RESUMO

Leprosy is a chronic infectious disease caused by Mycobacterium leprae infection in susceptible individuals. Without proper clinical diagnosis and treatment, leprosy can have a poor prognosis; however, diagnosing leprosy is challenging. We present a case of leprosy with extensive skin infiltration and involvement of the turbinate mucosa and multiple lymph nodes with increased FDG uptake on PET/CT, mimicking malignancy.

19.
Artigo em Inglês | MEDLINE | ID: mdl-31981465

RESUMO

Despite the great effort, the only feasible access to non face-centered cubic ( FCC ) copper is by physical vapor deposition under high vacuum. We report the first observation of non- FCC copper in a series of alkynyl protected Cu 53 nanoclusters (NCs) obtained from solution phase synthesis. Determined by single-crystal X-ray crystallography, the total structures of Cu 53 (C≡CPhPh) 9 (dppp) 6 Cl 3 (NO 3 ) 9 and its two derivatives reveal their most prominent feature: an ABABC stacking sequence involving 41 Cu atoms. It can be regarded as a mixed FCC and HCP structure, which gives strong evidence that Cu can be arranged in non- FCC lattice at ambient condition when proper ligands are provided. To gain a deeper understanding of the formation mechanism of Cu NCs, characterization methods including X-ray absorption fine structure, XPS, ESI-MS, UV-vis, Auger spectroscopies and DFT calculations are carried out. It is revealed that Cu II successively coordinated with introduced ligands and changed to Cu I after bonding with phosphine. The following addition of NaBH 4 and the aging step further reduced it to the title NC. Their applications in homocoupling of phenylacetylene are also studied.

20.
J Cell Mol Med ; 2020 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-31983065

RESUMO

Chemokines and their receptors have been reported to drive immune cells into tumours or to be directly involved in the promotion or inhibition of the development of tumours. However, their expression in regional lymph node (LN) tissues in melanoma patients remains unknown. The present study investigated the relationship between the expression of mRNA of chemokines and their receptors and clinicopathology of the regional LN tissues of skin cutaneous melanoma (SKCM) patients available in The Cancer Genome Atlas. The relationship between chemokines and their receptors and the composition of immune cells within the tumour was analysed. In SKCM regional LN tissues, the high expression of 32 types of chemokines and receptors, namely CCL2, 4-5, 7-8, 13, 22-25, CCR1-9, CXCL9-13, 16, CXCR3, 5, 6, XCL1-2 and XCR1 in LN was associated with favourable patient prognosis. Conversely, high expression of CXCL17 was an indicator of poor prognosis. The expression of mRNA for CXCL9-11, 13, CXCR3, 6, CCL2, 4, 5, 7, 8, 25, CCR1, 2, 5, and XCL1, 2 in regional LN tissues was positively correlated with the fraction of CD8-positive T cells and M1 macrophages, and was negatively correlated with M0 macrophages. CCR4, 6-9, CCL13, 22, 23 and XCR1 were positively correlated with the fraction of memory B cells and naive T cells, and negatively correlated with M0 macrophages and resting mast cells, suggesting that chemokines and their receptors may affect the prognosis of patients by guiding immune cells into the tumour microenvironment to eliminate tumour cells.

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