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Wide bandgap semiconductors, particularly In2 O3 :Sn (ITO), are widely used as transparent conductive electrodes in optoelectronic devices. Nevertheless, due to the strohave beenng scattering probability of high-concentration oxygen vacancy (VO ) defects, the mobility of ITO is always lower than 40 cm2 V-1 s-1 . Recently, hydrogen-doped In2 O3 (In2 O3 :H) films have been proven to have high mobility (>100 cm2 V-1 s-1 ), but the origin of this high mobility is still unclear. Herein, a high-resolution electron microscope and theoretical calculations are employed to investigate the atomic-scale mechanisms behind the high carrier mobility in In2 O3 :H films. It is found that VO can cause strong lattice distortion and large carrier scattering probability, resulting in low carrier mobility. Furthermore, hydrogen doping can simultaneously reduce the concentration of VO , which accounts for high carrier mobility. The thermal stability and acid-base corrosion mechanism of the In2 O3 :H film are investigated and found that hydrogen overflows from the film at high temperatures (>250 °C), while acidic or alkaline environments can cause damage to the In2 O3 grains themselves. Overall, this work provides insights into the essential reasons for high carrier mobility in In2 O3 :H and presents a new research approach to the doping and stability mechanisms of transparent conductive oxides.
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The Yangtze River Estuary is the terminal sink of terrestrial per- and polyfluoroalkyl substances (PFAS) from the Yangtze River, while the environmental fate characteristics of legacy and emerging PFAS around this region have rarely been discussed. Here, 24 targeted PFAS in seawater, sediments, suspended particulate matter (SPM), and plankton in the offshore region adjacent to this estuary were investigated. The three dominant PFAS in all phases were perfluorooctanoic acid (PFOA, 23.8-61.9%), perfluorobutanoic acid (PFBA, 23.6-42.8%), and perfluoro(2-methyl-3-oxahexanoic) acid (HFPO-DA, 6.1-12.1%), and perfluoro-1-butane sulfonamide (FBSA, 0.1-7.3%) was first detected. The horizontal distributions of PFAS were dependent on salinity and disturbed by multiple water masses, while the vertical variations could be explained by their different partitioning characteristics in the water-SPM-sediment system (partition coefficients, Logâ¯Kd and Logâ¯Koc) and plankton (bioaccumulation factors, Log BAF). Although physical mixing was the major driver for PFAS settling (>83.7%), the absolute settling amount caused by the biological pump was still high (150.00-41994.65 ng m-2 day-1). More importantly, we found unexpected high Logâ¯Kd values of PFBA (2.24-4.55) and HFPO-DA (2.26-4.67), equal to PFOA (2.28-4.72), which brought concerns about their environmental persistence. Considering the increased detection of short-chain and emerging PFAS, more comprehensive environmental behaviors analysis is required urgently.
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Due to the increase in nanoplastics (NPs) abundance in aquatic environments, their effects on phytoplankton have aroused large research attention. In this study, 100 nm sized polystyrene NPs were chosen to investigate their effecting performance and mechanisms on a typical dinoflagellates Alexandrium tamarense. The results indicated the population growth and photosynthetic efficiencies of A. tamarense were significantly inhibited by NPs exposure, as well as the increase in cellular total carotenoids and paralytic shellfish toxins (PSTs). Meanwhile, the cellar ROS levels increased, corresponding to the increased activities or contents of multiple antioxidant components, including SOD, CAT, GPX, GR, GSH and GSSG. The transcriptional results support the physiological-biochemical results and further revealed the down-regulation of genes encoding the light reaction centers (PSI and PSII) and up-regulation of genes encoding the antioxidant components. Up-regulation of genes encoding key enzymes of the Calvin cycle and glycolytic pathway together with the TCA cycle could accelerate organic carbon and ATP production for A. tamarense cells resistant to NPs stress. Finally, more Glu and acetyl-CoA produced by the enhanced GSH cycle and the glycolytic pathway, respectively, accompanied by the up-regulation of Glu and Arg biosynthesis genes supported the increase in the PST contents under NPs exposure. This study established a data set involving physiological-biochemical changes and gene information about marine dinoflagellates responding to NPs, providing a data basis for further evaluating the ecological risk of NPs in marine environments.
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Dinoflagelados , Fotosíntesis , Poliestirenos , Dinoflagelados/metabolismo , Dinoflagelados/efectos de los fármacos , Poliestirenos/química , Fotosíntesis/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Antioxidantes/metabolismo , Nanopartículas/química , Estrés Oxidativo/efectos de los fármacos , Toxinas Marinas , Microplásticos/toxicidadRESUMEN
Microalgae act as the entrance of polybrominated diphenyl ethers (PBDEs) from abiotic to biotic environments, which controlled the environmental fate of PBDEs in aquatic environments. Combing with typical coastal environmental characteristics including extracellular polymer substances (EPS) enrichment, light limitation and nitrogen starvation, the changes of adsorption and absorption kinetics of BDE-47 by Chlorella sp. and the role of EPS therein were investigated. The results quantified the adsorption and absorption kinetics of BDE-47 by Chlorella sp. cells and fitted it by the Lagergren pseudo first order model. Furthermore, we found the adsorption and absorption kinetics could be changed by the above mentioned environmental factors. To be specific, the total BDE-47 adsorption amounts per microalgal cell were increased as the increase of ambient EPS (proteins or carbohydrates), attributing to the increase of soluble (SL)-EPS contents; increased total BDE-47 adsorption amounts but decreased absorption rates were found under light limitation and nitrogen starvation, which were attributed to increased bound (B)-EPS contents and protein/carbohydrates (P/C) ratios therein, respectively. Therefore, our study elucidated the adsorption and absorption kinetics of PBDEs by microalgae could be influenced by ambient environmental changes, clarified the roles of SL-EPS, B-EPS contents and P/C ratios, providing a solid basis for evaluating the environmental fate of PBDEs in the marine environments.
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Chlorella , Microalgas , Éteres Difenilos Halogenados/metabolismo , Adsorción , Chlorella/metabolismo , Cinética , Microalgas/metabolismo , Nitrógeno , Carbohidratos , PolímerosRESUMEN
The fields of electronic skin, man-machine interaction, and health monitoring require flexible pressure sensors with great sensitivity. However, most microstructure designs utilized to fabricate high-performance pressure sensors require complex preparation processes. Here, MXene/polyaniline (PANI) foam with 3D porous structure is achieved by using a steam-induced foaming method. Based on the structure, a flexible piezoresistive sensor is fabricated. It exhibits high sensitivity (690.91 kPa-1 ), rapid response, and recovery times (106/95 ms) and outstanding fatigue resistance properties (10 000 cycles). The MXene/PANI foam-based pressure sensor can swiftly detect minor pressure and be further used for human activity and health monitoring.
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Compuestos de Anilina , Vapor , Humanos , Porosidad , AerosolesRESUMEN
Increasing marine microplastics (MPs) pollution potentially threatens the stability of phytoplankton community structures in marine environments. MPs toxicities to microalgae are largely determined by particle size, while the size-dependent mechanisms are still not fully understood. In this study, two sizes (0.1 µm and 1 µm) of polystyrene (PS) MPs were used as experimental targets to systemically compare their different effecting mechanisms on the marine model diatom Thalassiosira pseudonana with respect to oxidative stress and photosynthesis. The results indicated the toxicity of 1 µm sized MPs was higher than 0.1 µm sized MPs regarding to population growth. In condition of similar microalgal population inhibition rates, we found more enhanced cellular oxidative stress and cell death happened in the 1 µm MPs treatments, which could be linked to higher zeta potential of 1 µm MPs and more severe cell surface damage; microalgal surface light shading and cellular pigments decline were more obvious in the 0.1 µm MPs treatment, which could be linked to high aggregation abilities of 0.1 µm MPs. Gene expressions supported the morphological and physiological findings on the transcriptional level. Environmental related MPs concentrations (5 µg L-1) also aroused gene expression changes of T. pseudonana while more changing genes were found under 0.1 µm MPs than 1 µm MPs. These results provide novel insights into the size-dependent mechanisms of MPs toxicity on marine microalgae, as well as their potential influence on the marine environment.
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Diatomeas , Microalgas , Contaminantes Químicos del Agua , Diatomeas/genética , Microalgas/genética , Microplásticos/toxicidad , Estrés Oxidativo , Fotosíntesis , Plásticos , Poliestirenos/toxicidad , Contaminantes Químicos del Agua/toxicidadRESUMEN
As a new member of 2D materials, 2D tellurium (Te) has recently attracted much attention due to its intriguing properties. Through hydrothermal processing, 2D Te with tunable thickness and size has been realized, and its growth mechanism has also been studied. However, the tailored growth of 2D Te nanoflakes with symmetrical morphologies and interfacial moiré fringes has never been reported. Here, 2D Te nanoflakes have been prepared using the hydrothermal method, and mirror-symmetrical shapes (including "V-shape," "heart-shape," and "paper airplane-shape") with obvious moiré fringes in the middle of the nanoflakes are observed. Comprehensive transmission electron microscopy (TEM) techniques are utilized for structural characterization of these nanoflakes, especially the moiré fringes in the symmetry axis region of the nanoflakes. The systematic analyses of the moiré fringes and the observation of obvious overlapping edges of the composing nanoflakes from the cross-sectional samples reveal the possible mechanism of morphological evolution for these symmetrical nanoflakes. These details may fill the research gap in the controllable growth of 2D Te nanomaterials, pave the way for the fabrication of 2D Te moiré superlattices and in-plane homojunctions, and promote their future versatile applications.
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BACKGROUND: Anoikis resistance plays a critical role in the tumor metastasis by allowing survival of cancer cells in the systemic circulation. We previously showed that long non-coding RNAs APOC1P1-3 (lncRNA APOC1P1-3) inhibit apoptosis of breast cancer cells. In this study, we explored its role in anoikis resistance. METHODS: We induced anoikis resistance in two breast cancer cell lines (MCF-7 and MDA-MB-231) under anchorage-independent culture conditions and studied lncRNA APOC1P1-3 effects on apoptosis. Using Dual-Luciferase activity assay, we determined whether it specifically binds to miRNA-188-3P. We further explored its role in lung metastasis by injecting MDA-MB-231 and MDA-MB-231-APOC1P1-3-knock-down cells in female BALB/c nude mice. RESULTS: We found that lncRNA APOC1P1-3 suppressed early apoptosis of these cells (demonstrated by gain or loss of their function, respectively) and promoted anoikis resistance via reducing activated- Caspase 3, 8, 9 and PARP. Moreover, it specifically binds to the target miRNA-188-3p acting as a "sponge" to block the inhibition of Bcl-2 (an anti-apoptosis protein). CONCLUSIONS: Our study supports a theory that lncRNA APOC1P1-3 can promote development of breast cancer metastasis via anoikis resistance by specifically binding to miRNA-188-3p to block the inhibition of Bcl-2.
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BACKGROUND: This an update of a Cochrane Review. Paraquat is a widely used herbicide, but is also a lethal poison. In some low- and middle-income countries (LMICs) paraquat is commonly available and inexpensive, making poisoning prevention difficult. Most of the people poisoned by paraquat have taken it as a means of self-poisoning. Standard treatment for paraquat poisoning prevents further absorption and reduces the load of paraquat in the blood through haemoperfusion or haemodialysis. The effectiveness of standard treatments is extremely limited. The immune system plays an important role in exacerbating paraquat-induced lung fibrosis. Immunosuppressive treatment using glucocorticoid and cyclophosphamide in combination has been developed and studied as an intervention for paraquat poisoning. OBJECTIVES: To assess the effects of glucocorticoid with cyclophosphamide for moderate to severe oral paraquat poisoning. SEARCH METHODS: The most recent searches were run in September 2020. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Injuries Trials Register), Ovid MEDLINE(R), Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE Daily and Ovid OLDMEDLINE, Embase Classic + Embase (Ovid), ISI WOS (SCI-EXPANDED, SSCI, CPCI-S, and CPSI-SSH), and trials registries. We also searched the following three resources: China National Knowledge Infrastructure database (CNKI ); Wanfang Data (); and VIP () on 12 November 2020. We examined the reference lists of included studies and review papers. SELECTION CRITERIA: We included randomised controlled trials (RCTs). For this update, in accordance with Cochrane Injuries' Group policy (2015), we included only prospectively registered RCTs for trials published after 2010. We included trials which assessed the effects of glucocorticoid with cyclophosphamide delivered in combination. Eligible comparators were standard care (with or without a placebo), or any other therapy in addition to standard care. Outcomes of interest included mortality and infections. DATA COLLECTION AND ANALYSIS: We calculated the mortality risk ratio (RR) and 95% confidence interval (CI). Where possible, we summarised data for all-cause mortality at relevant time periods (from hospital discharge to three months after discharge) in meta-analysis, using a fixed-effect model. We conducted sensitivity analyses based on factors including whether participants were assessed at baseline for plasma paraquat levels. We also reported data on infections within one week after initiation of treatment. MAIN RESULTS: We included four trials with a total of 463 participants. The included studies were conducted in Taiwan (Republic of China), Iran, and Sri Lanka. Most participants were male. The mean age of participants was 28 years. We judged two of the four included studies, including the largest and most recently conducted study (n = 299), to be at low risk of bias for key domains including sequence generation. We assessed one study to be at high risk of selection bias and another at unclear risk, since allocation concealment was either not mentioned in the trial report or explicitly not undertaken. We assessed three of the four studies to be at unclear risk of selective reporting, as no protocols could be identified. An important source of heterogeneity amongst the included studies was the method of assessment of participants' baseline severity using analysis of plasma levels (two studies employed this method, whilst the other two did not). No studies assessed the outcome of mortality at 30 days following ingestion of paraquat. Low-certainty evidence from two studies indicates that glucocorticoids with cyclophosphamide in addition to standard care may slightly reduce the risk of death in hospital compared to standard care alone ((RR 0.82, 95% CI 0.68 to 0.99; participants = 322); results come from sensitivity analysis excluding studies not assessing plasma at baseline). However, we have limited confidence in this finding as heterogeneity was high (I2 = 77%) and studies varied in terms of size and comparators. A single large study provided data showing that there may be little or no effect of treatment at three months post discharge from hospital (RR 0.98, 95% CI 0.85 to 1.13; 1 study, 293 participants; low-certainty evidence); however, analysis of long-term results amongst participants whose injuries arose from self-poisoning must be interpreted with caution. We remain uncertain of the effect of glucocorticoids with cyclophosphamide on infection within one week after initiation of the treatment; this outcome was assessed by two small studies only (31 participants, very low-certainty evidence) that considered leukopenia as a proxy or risk factor for infection. Neither study reported infections in any participants. AUTHORS' CONCLUSIONS: Low-certainly evidence suggests that glucocorticoids with cyclophosphamide in addition to standard care may slightly reduce mortality in hospitalised people with oral paraquat poisoning. However, we have limited confidence in this finding because of substantial heterogeneity and concerns about imprecision. Glucocorticoids with cyclophosphamide in addition to standard care may have little or no effect on mortality at three months after hospital discharge. We are uncertain whether glucocorticoid with cyclophosphamide puts patients at an increased risk of infection due to the limited evidence available for this outcome. Future research should be prospectively registered and CONSORT-compliant. Investigators should attempt to ensure an adequate sample size, screen participants for inclusion rigorously, and seek long-term follow-up of participants. Investigators may wish to research the effects of glucocorticoid in combination with other treatments.
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Ciclofosfamida/uso terapéutico , Glucocorticoides/uso terapéutico , Herbicidas/envenenamiento , Inmunosupresores/uso terapéutico , Paraquat/envenenamiento , Fibrosis Pulmonar/tratamiento farmacológico , Adulto , Sesgo , Causas de Muerte , Quimioterapia Combinada/métodos , Femenino , Humanos , Masculino , Intoxicación/tratamiento farmacológico , Intoxicación/mortalidad , Fibrosis Pulmonar/inducido químicamente , Fibrosis Pulmonar/inmunología , Fibrosis Pulmonar/mortalidad , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores de TiempoRESUMEN
2D wide-bandgap semiconductors demonstrate great potential in fabricating solar-blind ultraviolet (SBUV) photodetectors. However, the low responsivity of 2D solar-blind photodetectors still limits their practical applications. Here, high-responsivity solar-blind photodetectors are achieved based on 2D bismuth oxychloride (BiOCl) flakes. The 2D BiOCl photodetectors exhibit a responsivity up to 35.7 A W-1 and a specific detectivity of 2.2 × 1010 Jones under 250 nm illumination with 17.8 µW cm-2 power density. In particular, the enhanced photodetective performances are demonstrated in BiOCl photodetectors with increasing ambient temperature. Surprisingly, their responsivity can reach 2060 A W-1 at 450 K under solar-blind light illumination, maybe owing to the formation of defective BiOCl grains evidenced by in situ transmission electron microscopy. The high responsivity throughout the solar-blind range indicates that 2D BiOCl is a promising candidate for SBUV detection.
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Foot-and-mouth disease virus (FMDV) is the etiological agent of a highly contagious disease that affects cloven-hoofed animals. Virus-like particles (VLPs) can induce a robust immune response and deliver DNA and small molecules. In this study, a VLP-harboring pcDNA3.1/P12A3C plasmid was generated, and the protective immune response was characterized. Guinea pigs were injected with VLPs, naked DNA vaccine, DNA-loaded VLPs, or phosphate-buffered saline twice subcutaneously at four-week intervals. Results demonstrated that the VLPs protected the naked DNA from DNase degeneration and delivered the DNA into the cells in vitro. The DNA-loaded VLPs and the VLPs alone induced a similar level of specific antibodies (P > 0.05) except at 49 dpv (P < 0.05). The difference in interferon-γ was consistent with that in specific antibodies. The levels of neutralizing antibodies induced by the DNA-loaded VLPs were significantly higher than those of other samples (P < 0.01). Similarly, the lymphocyte proliferation by using DNA-loaded VLPs was significantly higher than those using other formulas after booster immunization. Vaccination with DNA-loaded VLPs provided higher protection (100%) against viral challenge compared with vaccination with VLPs (75%) and DNA vaccine (25%). This study suggested that VLPs can be used as a delivery carrier for DNA vaccine. In turn, the DNA vaccine can enhance the immune response and prolong the serological duration of the VLP vaccine. This phenomenon contributes in providing complete protection against the FMDV challenge in guinea pigs and can be valuable in exploring novel nonreplicating vaccines and controlling FMD in endemic countries worldwide.
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ADN Viral/administración & dosificación , Virus de la Fiebre Aftosa , Fiebre Aftosa/prevención & control , Vacunas de Partículas Similares a Virus/uso terapéutico , Vacunas Virales/uso terapéutico , Animales , ADN Viral/genética , Ensayo de Inmunoadsorción Enzimática , Femenino , Fiebre Aftosa/inmunología , Fiebre Aftosa/virología , Virus de la Fiebre Aftosa/genética , Virus de la Fiebre Aftosa/inmunología , Cobayas , Pruebas de Neutralización , Vacunas de Partículas Similares a Virus/administración & dosificación , Vacunas Virales/administración & dosificaciónRESUMEN
The configurations of core/shell nanowires (NWs) and quantum dots (QDs) decorating NWs have found great applications in forming optoelectronic devices thanks to their superior performances. The combination of the two configurations would expect to bring more benefits, however, the nanometer-scale electrostatic properties of the QD/buffer layer/NW heterostructures are still unrevealed. In this study, the InAs QDs decorating GaAs/AlAs core/shell NWs are systemically studied both experimentally and theoretically. The layered atomic structures, chemical information, and anisotropic strain conditions are characterized by comprehensive transmission electron microscopy (TEM) techniques. Quantitative electron holography analyses show a large number of electrons accumulating in the InAs QD, especially at the dot apex, and charges of reversed signs and similar densities are observed to distribute at the sequential interfaces, leaving great amounts of holes in the NW core. Theoretical calculations including simulated heterostructural band structures, interfacial charge transfer, and chemical bonding analysis are in good accordance with the experimental results, and prove the important role of the AlAs buffer layer in adjusting the heterostructural band structure as well as forming stable InAs QDs on the NW surfaces. These results could be significant for achieving related optoelectronic devices with better stability and higher efficiency.
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MoS2 2D nanosheets (NS) with intercalated 0D quantum dots (QDs) represent promising structures for creating low-dimensional (LD) resistive memory devices. Nonvolatile memristors based 2D materials demonstrate low power consumption and ultrahigh density. Here, the observation of a photoinduced phase transition in the 2D NS/0D QDs MoS2 structure providing dynamic resistive memory is reported. The resistive switching of the MoS2 NS/QD structure is observed in an electric field and can be controlled through local QD excitations. Photoexcitation of the LD structure at different laser power densities leads to a reversible MoS2 2H-1T phase transition and demonstrates the potential of the LD structure for implementing a new dynamic ultrafast photoresistive memory. The dynamic LD photomemristive structure is attractive for real-time pattern recognition and photoconfiguration of artificial neural networks in a wide spectral range of sensitivity provided by QDs.
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The phase stability of ZnO in a quantum-confinement size regime (sub-2-nm) remains fiercely debated. Applying in situ (scanning) transmission electron microscopy, we present the atomistic view of the phase transitions from the original wurtzite structure to an intermediate body-centered tetragonal and h-MgO structure under tensile strain in quantum-confined ZnO nanowires. Strikingly, such structural transitions are reversible after releasing the stress. Further theoretical calculations mirror the transition pathway and provide basic insight into the overall landscape regarding surface- and strain-dependent phase transition behavior. Our results provide the critical piece to solve the puzzle in phase stability of ZnO, which may prove essential for advancing a variety of nanotechnologies, e.g., quantum-dot light-emitting devices.
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BACKGROUND: As the first member of the metastasis-associated protein (MTA) family, MTA1 and another MTA family member, MTA2, have both been reported to promote breast cancer progression and metastasis. However, the difference and relationship between MTA1 and MTA2 have not been fully elucidated. METHODS: Transwell assays were used to assess the roles of MTA1 and MTA2 in the metastasis of ZR-75-30 luminal B breast cancer cells in vitro. Immunoblotting and qRT-PCR were used to evaluate the effect of MTA1 overexpression on MTA2. Proteases that cleave MTA2 were predicted using an online web server. The role of neutrophil elastase (NE) in MTA1 overexpression-induced MTA2 downregulation was confirmed by specific inhibitor treatment, knockdown, overexpression and immunocytochemistry, and NE cleavage sites in MTA2 were confirmed by MTA2 truncation and mutation. The effect of MTA1 overexpression on the intrinsic inhibitor of NE, elafin, was detected by qRT-PCR, immunoblotting and treatment with inhibitors. RESULTS: MTA1 overexpression inhibited, while MTA2 promoted the metastasis of ZR-75-30 cells in vitro. MTA1 overexpression downregulated MTA2 expression at the protein level rather than the mRNA level. NE was predicted to cleave MTA2 and was responsible for MTA1 overexpression-induced MTA2 degradation. NE was found to cleave MTA2 in the C-terminus at the 486, 497, 542, 583 and 621 sites. MTA1 overexpression activated NE by downregulating elafin in a histone deacetylase- and DNA methyltransferase-dependent manner. CONCLUSIONS: MTA1 and MTA2 play opposing roles in the metastasis of ZR-75-30 luminal B breast cancer cells in vitro. MTA1 downregulates MTA2 at the protein level by epigenetically repressing the expression of elafin and releasing the inhibition of neutrophil elastase, which cleaves MTA2 in the C-terminus at multiple specific sites.
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Histona Desacetilasas/metabolismo , Proteolisis , Proteínas Represoras/metabolismo , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Línea Celular Tumoral , ADN (Citosina-5-)-Metiltransferasa 1/metabolismo , Regulación hacia Abajo/genética , Elafina/farmacología , Histona Desacetilasas/química , Humanos , Elastasa de Leucocito/antagonistas & inhibidores , Elastasa de Leucocito/metabolismo , Modelos Biológicos , Metástasis de la Neoplasia , Proteínas Represoras/química , TransactivadoresRESUMEN
In situ transmission electron microscopy investigation of structural transformation in III-V nanowires is essential for providing direct insight into the structural stability of III-V nanowires under elevated temperature. In this study, through in situ heating investigation in a transmission electron microscope, the detailed structural transformation of InAs nanowires from wurtzite structure to zinc-blende structure at the catalyst/nanowire interface is witnessed on the atomic level. Through detailed structural and dynamic analysis, it was found that the nucleation site of each new layer of InAs and catalyst surface energy play a decisive role in the growth of the zinc-blende structure. This study provides new insights into the growth mechanism of zinc-blende-structured III-V nanowires.
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Seven resorcylic acid lactones (RALs) including five new analog rhinoclactones, A-E (1, 2, 4-6), were isolated from an endophytic fungus Rhinocladiella similis in the plant Agriophyllum squarrosum collected from the Tengger Desert of the Ningxia Province, China. The structures of these new compounds were determined by HR-ESI-MS (High Resolution Electrospray Ionization Mass Spectrometry), NMR data, modified Mosher's method, and X-ray diffraction experiments. All compounds isolated from this fungus possessed the 16-OMe/14-OH, not the common 16-OH/14-OH or 16-OH/14-OMe groups on the aromatic ring, which are rarely found in nature. Compound 7 displayed cytotoxic activities against HCT116 and HeLa cancer cell lines. The possible biosynthesis of 1-7 is suggested, and the potential ecological roles of these fungal secondary metabolites is discussed.
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Ascomicetos/química , Chenopodiaceae/microbiología , Citotoxinas , Endófitos/química , Lactonas , Citotoxinas/química , Citotoxinas/aislamiento & purificación , Citotoxinas/farmacología , Células HCT116 , Células HeLa , Humanos , Lactonas/química , Lactonas/aislamiento & purificación , Lactonas/farmacologíaRESUMEN
To identify the role and to explore the mechanism of extracellular 5'-nucleotidase (CD73) in human breast cancer growth, CD73 expression was measured firstly in breast cancer tissues and cell lines, and then interfered with or over-expressed by recombinant lentivirus in cell lines. Impacts of CD73 on breast cancer cell proliferation and cell cycle were investigated with colony formation assay, CCK-8 and flow cytometry. The relationship between CD73 and AKT/GSK-3ß/ß-catenin pathway was assessed with adenosine, adenosine 2A receptor antagonist (SCH-58261), adenosine 2A receptor agonist (NECA), CD73 enzyme inhibitor (APCP) and Akt inhibitor (MK-2206). Moreover, the effect of CD73 on breast cancer growth in vivo was examined with human breast cancer transplanting model of nude mice. The results showed that the expression of CD73 was high in breast cancer tissues and increased with advanced tumor grades and lympho-node status. CD73 expression was higher in more malignant cells, and CD73 overexpression promoted breast cancer cell proliferation in both in vivo and in vitro. It activated AKT/GSK-3ß/ß-catenin/cyclinD1 signaling pathway through CD73 enzyme activity and other mechanism.
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5'-Nucleotidasa/metabolismo , Neoplasias de la Mama/patología , Proliferación Celular , Ciclina D1/metabolismo , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , beta Catenina/metabolismo , 5'-Nucleotidasa/genética , Animales , Apoptosis , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Ciclo Celular , Movimiento Celular , Ciclina D1/genética , Femenino , Proteínas Ligadas a GPI/genética , Proteínas Ligadas a GPI/metabolismo , Glucógeno Sintasa Quinasa 3 beta/genética , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Pronóstico , Proteínas Proto-Oncogénicas c-akt/genética , Transducción de Señal , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de Xenoinjerto , beta Catenina/genéticaRESUMEN
Semiconductor light-emitting diodes (LEDs), especially GaN-based heterostructures, are widely used in light illumination. The lack of inversion symmetry of wurtzite crystal structures and the lattice mismatch at heterointerfaces cause large polarization fields with contributions from both spontaneous polarization and piezoelectric polarization, which in turn results in obvious quantum confined stark effect. It is possible to alleviate this effect if the local electrostatic fields and band alignment induced charge redistribution can be quantitatively determined across the heterostructures. In this Concept, the applications of electron holography to investigate semiconductor LEDs are summarized. Following the off-axis electron holography scheme, the GaN-based LED heterostructures including InGaN/GaN-based quantum wells, other GaN-based quantum wells, and other forms of GaN-based LED materials are discussed, focusing on the local potential drops, polarization fields, and charge distributions. Moreover, GaAs-based LED heterostructures are briefly discussed. The in-line electron holography scheme emphasizes the capability of large area strain mapping across LED heterostructures with high spatial resolution and accuracy, which is combined with quantitative electrostatic measurements and other advanced transmission electron microscopy characterizations to provide an overall nanometer scale perspective of LED devices for further improvement in their electric and optical properties.
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Monolayer MoS2 is considered to be one of the best candidates for next generation electronics because of its ultra-thin body and direct band gap. However, MoS2 based transistors have relatively low photoresponsivity, field effect mobility and narrow response spectrum range, which hinder the application of MoS2 in optoelectronic devices. Here, based on the enhancement of localized surface plasmon resonance (LSPR), a simple method of depositing Ag nanoparticles on the MoS2 surface is used. By adjusting the size of Ag nanoparticles, the response spectral range of phototransistor is broadened from red to near ultra-violet. The photoresponsivity gains an increase of 470% up to 2.97 × 104 A W-1 at 610 nm, and the response time also shows a decrease to some extent. The enhanced responsivity is comparable to those of devices encapsulated with high-quality dielectrics, and superior over other reported monolayer MoS2 in ambient conditions. The high responsivity and working current enables a wide range of device applications. This work provides a viable route towards performance enhancement of two-dimensional phototransistors.