Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 52
Filtrar
1.
Small ; : e2403073, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38966892

RESUMO

Spin injection, transport, and detection across the interface between a ferromagnet and a spin-carrying channel are crucial for energy-efficient spin logic devices. However, interfacial conductance mismatch, spin dephasing, and inefficient spin-to-charge conversion significantly reduce the efficiency of these processes. In this study, it is demonstrated that an all van der Waals heterostructure consisting of a ferromagnet (Fe3GeTe2) and Weyl semimetal enables a large spin readout efficiency. Specifically, a nonlocal spin readout signal of 150 mΩ and a local spin readout signal of 7.8 Ω is achieved, which reach the signal level useful for practical spintronic devices. The remarkable spin readout signal is attributed to suppressed spin dephasing channels at the vdW interfaces, long spin diffusion, and efficient charge-spin interconversion in Td-MoTe2. These findings highlight the potential of vdW heterostructures for spin Hall effect-enabled spin detection with high efficiency, opening up new possibilities for spin-orbit logic devices using vdW interfaces.

2.
Nanomaterials (Basel) ; 13(2)2023 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-36678090

RESUMO

The writing performance of the easy-cone magnetic tunnel junction (MTJ) and perpendicularly magnetized MTJ (pMTJ) under various temperatures was investigated based on the macrospin model. When the temperature is changed from 273 K to 373 K, the switching current density of the pMTJ changes by 56%, whereas this value is only 8% in the easy-cone MTJ. Similarly, the temperature-induced variation of the switching delay is more significant in the pMTJ. This indicates that the easy-cone MTJ has a more stable writing performance under temperature variations, resulting in a wider operating temperature range. In addition, these two types of MTJs exhibit opposite temperature dependence in the current overdrive and write error rate. In the easy cone MTJ, these two performance metrics will reduce as temperature is increased. The results shown in this work demonstrate that the easy-cone MTJ is more suitable to work at high temperatures compared with the pMTJ. Our work provides a guidance for the design of STT-MRAM that is required to operate at high temperatures.

3.
Cell Death Dis ; 13(5): 478, 2022 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-35589690

RESUMO

Cancer-associated fibroblasts (CAFs) are one of the most enriched components of Hepatocellular carcinoma (HCC) microenvironment, which are tightly related to the metastasis and invasion of HCC. We identified a mechanism by which CAF-derived chemokine CCL5 enhanced HCC metastasis by triggering the HIF1α/ZEB1 axis. We demonstrated that CAFs derived from HCC tissues promoted the migration and invasion of HCC cells and facilitated metastasis to the lung of NOD/SCID mice. Then the chemokine antibody array elucidated the higher chemokine CCL5 level secreted by CAFs than by paracancerous tissue fibroblasts (PTFs). Mechanistically, we found that CAF-derived CCL5 inhibited the ubiquitination and degradation of hypoxia-inducible factor 1 alpha (HIF1α) by binding to specific receptors, maintained HIF1α under normoxia, thereby up-regulated the downstream gene zinc finger enhancer-binding protein 1 (ZEB1) and induced epithelial-mesenchymal transition (EMT), ultimately validating its ability to promote lung metastasis of HCC. And this novel mechanism may have association with poor prognosis. Taken together, targeting CAF-derived CCL5 mediated HIF1α/ZEB1 cascade possibly propose a new therapeutic route for HCC.


Assuntos
Fibroblastos Associados a Câncer , Carcinoma Hepatocelular , Neoplasias Hepáticas , Animais , Fibroblastos Associados a Câncer/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Quimiocina CCL5/genética , Quimiocina CCL5/metabolismo , Transição Epitelial-Mesenquimal/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/patologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Metástase Neoplásica/patologia , Microambiente Tumoral
4.
Plant Cell Rep ; 41(4): 905-920, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34982198

RESUMO

KEY MESSAGE: CitWRKY28 and CitNAC029 are involved in cuticular wax synthesis as indicated by the comparative analysis of fruit aliphatic wax content between Citrus reticulata and Citrus trifoliata and gene co-expression analysis. Cuticular wax covers the fruit surface, playing important roles in reduction of fruit water loss and resistance to pathogen invasion. However, there is limited research on the synthesis and transcriptional regulation of cuticular wax in citrus fruit. In this study, we characterized the variations of aliphatic wax in HJ (Citrus reticulata) and ZK (Citrus trifoliata) from young fruit to mature fruit, as well as performed transcriptome sequencing on 27 samples at different fruit developmental stages. The results revealed that the ZK fruit always had a higher aliphatic wax content than the HJ fruit during development. qRT-PCR analysis demonstrated that two KCS genes, CitKCS1 and CitKCS12, had the most significant difference in expression between HJ and ZK. Furthermore, a heterologous expression assay in Arabidopsis indicated that CitKCS1 and CitKCS12 are involved in cuticular wax synthesis. Subsequently, gene co-expression network analysis screened CitWRKY28 and CitNAC029. Dual luciferase and EMSA assays indicated that CitWRKY28 might bind to the promoter of CitKCS1 and CitKCS12 and CitNAC029 might bind to that of CitKCS1 to activate their expression. Moreover, CitWRKY28 and CitNAC029 could promote the accumulation of cuticular wax in Arabidopsis leaves. Our findings provide new insights into the synthesis and regulation of cuticular wax and valuable information for further mining of wax-related genes in citrus fruit.


Assuntos
Arabidopsis , Citrus , Arabidopsis/genética , Arabidopsis/metabolismo , Citrus/genética , Citrus/metabolismo , Frutas/metabolismo , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ceras/metabolismo
5.
J Exp Bot ; 73(3): 953-966, 2022 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-34599807

RESUMO

A Citrus sinensis R2R3 MYB transcription factor (CsMYB96) has previously been shown to be strongly associated with the expression of many genes related to wax biosynthesis in the fruit. In this study, CsMYB96 was found to alleviate water loss by simultaneously regulating the expression of genes encoding plasma membrane intrinsic proteins (CsPIPs) and wax-related genes. Expression profiling indicated that CsPIP1;1 and CsPIP2;4 had high expression that was representative of other aquaporins, and they were down-regulated in the peel of post-harvest citrus fruit. CsPIP2;4 was further characterized as the predominant CsPIP, with high expression and high-water channel activity. Transient overexpression of CsPIP2;4 accelerated water loss in citrus fruit. In silico analysis further indicated that the expression of CsMYB96 had a significant negative correlation with that of CsPIPs. In vivo and in vitro experiments confirmed that CsMYB96 was able to directly repress the expression of CsPIPs. In addition, CsMYB96 was able to activate wax-related genes and promote wax biosynthesis for defense against water loss. Transient and stable overexpression of CsMYB96 reduced water loss from both citrus fruit and Arabidopsis.


Assuntos
Citrus sinensis , Proteínas de Plantas , Fatores de Transcrição , Perda Insensível de Água , Ceras , Aquaporinas/metabolismo , Citrus sinensis/genética , Citrus sinensis/metabolismo , Frutas/genética , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Água/metabolismo , Perda Insensível de Água/genética , Ceras/metabolismo
6.
Carbohydr Polym ; 269: 118249, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34294286

RESUMO

Amphipathic starch (AS) with hydrophobic octenylsuccinate (OS) and hydrophilic carboxymethyl (CM) substituents was prepared by the carboxymethylation and octenylsuccinylation of starch for strong bonding to fiber and easy removal from sized yarn. Two series of AS derivatives with differential degrees of substitution (DS) and differential mole percentages of OS to total substituents (Pos) were examined to reveal the effects of Pos and DS values on bonding of the starch to cotton and polyester fibers. It was found that the amphipathic modification was able to significantly increase bonding strength of the starch. Combination of the CM and OS substituents could increase the bonding strength more than each one alone. Furthermore, desizing trial proved that the AS was desizable by either enzyme or oxidant desizing. Starch octenylsuccinylation and carboxymethylation was a good way for corn starch to achieve strong bonding to fibers and easy removal from sized yarns.

7.
Nanotechnology ; 32(33)2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-33957616

RESUMO

All inorganic perovskite nanocrystals CsPbX3(X = Cl, Br, I) are the great potential candidates for the application of high-performance light emitting diodes (LED) due to their high Photoluminescence Quantum Yield (PLQY), high defect tolerance, narrow full-width half-maximum and tunable wavelength of 410-700 nm. However, the application of red-emitting (630-650 nm) CsPbBrxI3-xnanocrystals are perplexed by phase segregation due to the composition of mixed halides and the difference in halide ion mobility. Herein, we provide an effective strategy to suppressing the migration of Br/I ions through Ni2+doping via a facile Hot-Injection method and the PLQY was improved as well. DFT calculations show that the introduction of Ni2+causes a slight contraction of the host crystal structure, which improves the bond energy between Pb and halides and reduces the level of surface defects. Therefore, the phase stability is improved by Ni2+doping because the phase segregation caused by ion migration in the mixed phase is effectively inhibited. Meanwhile, the non-radiative recombination in the exciton transition process is reduced and the PLQY is improved. What's more, benefiting from the suppressed ion migration and enhanced PLQY, we combine the Ni2+-doped CsPbBrxI3-xnanocrystals with different Br/I ratios and YAG: Ce3+phosphors as color conversion layers to fabricate high efficiency WLED. When the ratio of Br/I is 9:11, WLED has a color coordinate of (0.3621, 0.3458), the color temperature of 4336 K and presents a high luminous efficiency of 113.20 lm W-1, color rendering index of 94.9 under the driving current of 20 mA and exhibits excellent stability, which shows great potential in the application of LED.

8.
Langmuir ; 37(13): 4007-4015, 2021 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-33750135

RESUMO

Architectural design of hollow carbon spheres (HCSs) plays a vital role in improving their performance and expanding applications. The tailorable synthesis of bumpy or asymmetric HCSs with a refined structure remains a challenge. Herein, bumpy HCSs (BHCSs) and bumpy concave HCSs (BCHCSs) have been engineered. The synthesis involves the formation of a core/shell precursor via the surface polymerization of pyrrole monomers on polystyrene nanoparticles, followed by the controlled pyrolysis process under different conditions. In comparison with HCSs, the concave hollow structure can reduce the excessive interior cavity and maintain prevalent merits of hollow structures; the bumpy shell can improve the surface area and number of active sites, thus improving the kinetics as energy storage devices. As a result, among BCHCSs, BHCSs, and HCSs, BCHCSs exhibit optimal electrochemical performance. The lithium-ion hybrid capacitors employing BCHCSs as an anode can deliver an energy density of 0.2182 kW h kg-1 at a power density of 0.2235 kW kg-1. Overall, this study provides an innovative design and strategy for constructing unique carbon nano-architectures for energy storage.

9.
Int J Biol Macromol ; 166: 1460-1470, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33171182

RESUMO

The purpose of this work was to examine the influence of poly(sodium allyl sulfonate) (PSAS) branches on sizing properties of biological macromolecule (corn starch) for exploring a new anionic starch graft copolymer size (S-g-PSAS). Successful synthesis of S-g-PSAS samples was confirmed by energy dispersive X-ray spectrometer. Viscosity stability, adhesion, film properties and desizability of the samples were also investigated. Compared with HS, improved adhesion to cotton and viscose fibers, viscosity stability and desizability for S-g-PSAS as well as enhanced breaking elongation and bending endurance for S-g-PSAS film were exhibited. With the rise in grafting ratio, bonding forces to both fibers, viscosity stability and desizability of S-g-PSAS and its film properties such as breaking elongation and bending endurance, were gradually enhanced. These results indicated that S-g-PSAS showed potential for the use as a new starch-based size in the sizing of cotton and viscose warps.


Assuntos
Compostos Alílicos/química , Fibra de Algodão , Plastificantes/química , Amido/análogos & derivados , Adesivos/síntese química , Alcanossulfonatos/química , Elasticidade , Indústria Têxtil/métodos , Viscosidade , Zea mays/química
10.
BMC Ophthalmol ; 20(1): 326, 2020 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-32770964

RESUMO

BACKGROUND: It's necessary to analyze the role of VEGF, apelin, and HO-1 in patients with type 2 diabetes (T2DM), and to evaluate its relevance to diabetic retinopathy (DR). METHODS: T2DM patients who were treated in our hospital from December 1, 2018 to November 30, 2019 were included. T2DM patients were divided into non-DR (NDR) group, non-proliferative DR (NPDR) group, and proliferative DR (PDR) group. and healthy participants were selected as the control group. The value of VEGF, apelin, and HO1 in predicting PDR were analyzed by receiver operating characteristic (ROC) curve, and the relations of VEGF, apelin, HO-1 and clinical factors in PDR patients were analyzed by Pearson correlation analysis. RESULTS: A total of 295 participants were included. The level of FPG and HbAlc in PDR group were significantly higher than that of other groups (all p < 0.05); the level of VEGF and apelin in PDR group were significantly higher than that of other groups (all p < 0.05), but the level of HO-1 in PDR group were significantly less than that of other groups(p = 0.017); the AUC of VEGF, apelin, HO-1 and combined use was 0.806(95%CI: 0.779-0.861), 0.819(95%CI: 0.765-0.878), 0.808(95%CI: 0.733-0.869) and 0.902(95%CI: 0.822-0.958) respectively, the AUC, sensitivity, specificity of the three combined use was significantly higher than that of single VEGF, apelin, HO-1 use(all p < 0.05). The cutoff values of serum VEGF, apelin, and HO-1 levels for predicting PDR were 163.85 pg/ml, 8.27 ng/ml, and 26.06 mmol/L respectively. Serum VEGF, apelin, and HO-1 in patients with PDR was related to the time course of DM, FPG and HbAlc (all p < 0.05). CONCLUSIONS: VEGF, apelin and HO-1 are related to the progress of DR, and the combined use of VEGF, apelin and HO-1 is beneficial to the diagnosis and treatment of PDR.


Assuntos
Diabetes Mellitus Tipo 2 , Retinopatia Diabética , Apelina , Diabetes Mellitus Tipo 2/complicações , Retinopatia Diabética/diagnóstico , Heme Oxigenase-1 , Humanos , Curva ROC , Fator A de Crescimento do Endotélio Vascular
11.
J Clin Pharm Ther ; 45(6): 1414-1421, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32737938

RESUMO

WHAT IS KNOWN AND OBJECTIVES: Caffeine citrate is a commonly used methylxanthine for pharmacologic treatment of apnea of prematurity. The aim of this study was to develop and verify a population pharmacokinetic (PPK) model, which can provide a reference for individualized caffeine citrate treatment of apnea in Chinese premature infants. METHODS: A total of 88 serum concentration measurements from 46 preterm patients (median gestational age 29 weeks) were retrospectively collected and the relevant clinical data of patients were recorded. The PPK analysis was performed by non-linear mixed-effect modelling method using NONMEM. Allometric scaling was applied in the PPK analysis, and the final model was evaluated by graphic and statistical methods, including goodness-of-fit plots, normalized prediction distribution errors plots and bootstrap procedures. RESULTS: A one-compartment model with first-order elimination was successfully fitted to the data. The typical scaled values for the parameters clearance and volume of distribution (V) were 0.268 L/h and 109 L per 70 kg, respectively. The weight at the time of blood collection (CW) and post-natal age were identified as important predictors for pharmacokinetic parameters of caffeine. The evaluation process showed good stability and predictability of the final PPK model. WHAT IS NEW AND CONCLUSION: This is a complete PPK study of caffeine citrate in Chinese premature infants with apnea, which complements caffeine pharmacokinetic data of the premature from China. A final PPK model was developed which may serve as a beneficial tool for the use of caffeine citrate in the treatment of apnea in Chinese preterm infants.


Assuntos
Apneia/tratamento farmacológico , Cafeína/farmacocinética , Estimulantes do Sistema Nervoso Central/farmacocinética , Citratos/farmacocinética , Modelos Biológicos , Povo Asiático , Cafeína/administração & dosagem , Estimulantes do Sistema Nervoso Central/administração & dosagem , Citratos/administração & dosagem , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Doenças do Prematuro/tratamento farmacológico , Masculino , Dinâmica não Linear , Estudos Retrospectivos
12.
Nephrology (Carlton) ; 25(10): 749-757, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32542819

RESUMO

AIM: Gitelman syndrome (GS) is a rare inherited salt-losing renal tubulopathy. Data on clinical features and the pregnancy outcome for female GS patients in a large cohort are lacking. The study was aimed to explore the phenotype and pregnant issue for female GS patients. METHODS: GS cases from the National Rare Diseases Registry System of China (NRSC) were collected, and detailed clinical, laboratory and genetic data were analysed. Articles on pregnancy in GS were also systemically reviewed. RESULTS: A total of 101 GS patients were included; among them, 42.6% were female and 79.2% showed hypomagnesaemia. A lower proportion of female patients presented before 18 years of age, with less frequently reported polyuria, higher serum potassium and less urine sodium and chloride excretions. There was no gender difference in the sodium-chloride cotransporter (NCC) dysfunction evaluated by hydrochlorothiazide test. Twelve of the 43 female GS patients delivered after disease symptom onset, and their pregnancies were generally uneventful. As a group, pregnant GS patients had lower potassium levels in the first-trimester (P = .002) requiring higher potassium supplementation. After delivery, serum potassium (P = .02) and magnesium (P = .03) increased significantly. Both caesarean section and vaginal delivery were safe. CONCLUSION: Female GS patients may have a less severe phenotype with generally favourable outcomes of pregnancy. Intensive monitoring and increased potassium supplementation are necessary during pregnancy, especially in the first-trimester.


Assuntos
Parto Obstétrico , Síndrome de Gitelman , Potássio , Complicações na Gravidez , Membro 3 da Família 12 de Carreador de Soluto/genética , Desequilíbrio Hidroeletrolítico , Adulto , China/epidemiologia , Cloretos/urina , Parto Obstétrico/métodos , Parto Obstétrico/estatística & dados numéricos , Feminino , Síndrome de Gitelman/epidemiologia , Síndrome de Gitelman/genética , Síndrome de Gitelman/fisiopatologia , Síndrome de Gitelman/terapia , Humanos , Recém-Nascido , Magnésio/sangue , Masculino , Mutação , Poliúria/diagnóstico , Poliúria/etiologia , Potássio/sangue , Potássio/uso terapêutico , Gravidez , Complicações na Gravidez/epidemiologia , Complicações na Gravidez/etiologia , Complicações na Gravidez/fisiopatologia , Complicações na Gravidez/terapia , Resultado da Gravidez/epidemiologia , Eliminação Renal/genética , Sódio/urina , Membro 3 da Família 12 de Carreador de Soluto/metabolismo , Desequilíbrio Hidroeletrolítico/sangue , Desequilíbrio Hidroeletrolítico/etiologia , Desequilíbrio Hidroeletrolítico/terapia , Desequilíbrio Hidroeletrolítico/urina
13.
Nanoscale ; 12(10): 6104-6110, 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32129414

RESUMO

Hygroresponsive actuators harness minor fluctuations in the ambient humidity to realize energy harvesting and conversion, thus they are of profound significance in the development of more energy-saving and sustainable systems. However, most of the existing hygroresponsive actuators are only adaptive to wet environments with limited moving directions and shape morphing modes. Therefore, it is highly imperative to develop a hygroresponsive actuator that works in both wet and dry environments. In this work, we present a bidirectional actuator responsive to both wet and dry stimuli. Our strategy relies on the introduction of carbon nanotubes to provide transport channels for water molecules. The actuation is enabled by the rapid transport of water in and out of the system driven by the moist/dry surroundings owing to the transport channels. The resultant actuator demonstrates reconfiguration and locomotion with turnover frequency F = 30 min-1, coupled with the capability of lifting objects 6 times heavier and transporting cargos 63 times heavier than itself. Oscillations (24°) driven by dry air flow in a cantilever display a high frequency (2 Hz) and large amplitude. Furthermore, a touchless electronic device was constructed to output varying signals in response to humid and dry environments. Our work provides valuable guidance and implications for designing and constructing hygroresponsive actuators, and paves the way for next-generation robust autonomous devices to exploit energy from natural resources.

14.
Nat Nanotechnol ; 14(10): 945-949, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31427750

RESUMO

All-electric magnetization manipulation at low power is a prerequisite for a wide adoption of spintronic devices. Materials such as heavy metals1-3 or topological insulators4,5 provide good charge-to-spin conversion efficiencies. They enable magnetization switching in heterostructures with either metallic ferromagnets or with magnetic insulators. Recent work suggests a pronounced Edelstein effect in Weyl semimetals due to their non-trivial band structure6,7; the Edelstein effect can be one order of magnitude stronger than it is in topological insulators or Rashba systems. Furthermore, the strong intrinsic spin Hall effect from the bulk states in Weyl semimetals can contribute to the spin current generation8. The Td phase of the Weyl semimetal WTe2 (WTe2 hereafter) possesses strong spin-orbit coupling6,9 and non-trivial band structures10 with a large spin polarization protected by time-reversal symmetry in both the surface and bulk states9-11. Atomically flat surfaces, which can be produced with high quality12, facilitate spintronic device applications. Here, we use WTe2 as a spin current source in WTe2/Ni81Fe19 (Py) heterostructures. We report field-free current-induced magnetization switching at room temperature. A charge current density of ~2.96 × 105 A cm-2 suffices to switch the magnetization of the Py layer. With the charge current along the b axis of the WTe2 layer, the thickness-dependent charge-to-spin conversion efficiency reaches 0.51 at 6-7 GHz. At the WTe2/Py interface, a Dzyaloshinskii-Moriya interaction (DMI) with a DMI constant of -1.78 ± 0.06 mJ m-2 induces chiral domain wall tilting. Our study demonstrates the capability of WTe2 to efficiently manipulate magnetization and sheds light on the role of the interface in Weyl semimetal/magnet heterostructures.

15.
ACS Appl Mater Interfaces ; 11(33): 30116-30124, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31348639

RESUMO

Buckled hollow carbon nanospheres (BHCSs) integrate several attractive properties desired for a variety of potential applications. However, the development of a feasible and simple method for preparing BHCS nanoparticles remains a great challenge. Herein, we present a facile strategy for fabricating monodisperse BHCSs via the compression of intact hollow carbon nanospheres (HCSs) with improved mechanical strength. The essence of our strategy lies in the successful preparation of robust HCSs that can sustain large mechanical deformation during compression, based on the introduction of polyvinylpyrrolidone in the synthesis of HCS templates. Both experiments and finite element analyses are conducted to probe the deformation mechanism of buckling, suggesting that the residual stress introduced by pyrolysis of precursors plays a predominant role in the buckling process. Furthermore, the use of BHCSs as high-performance supercapacitors is demonstrated. Our work provides important insights into the engineering of robust amorphous carbon nanomaterials by the template method and mechanical modulation and provides an innovative synthetic strategy for fabricating asymmetric hollow spheres with potential for a diversity of applications.

16.
Opt Express ; 27(4): 5755-5763, 2019 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-30876171

RESUMO

We demonstrate the enhancement of femtosecond (fs) laser-induced filaments in air and nitrogen flow fields using a nanosecond (ns) laser. With the ns laser being imposed on the filaments, the length and the emission intensity of the filaments were largely increased. Temporally resolved spectra of the enhanced filaments were obtained. The results show that the ns laser enhanced the short-lifetime fluorescence of nitrogen, which comes from the transition processes of N2 +(B2Σu + - X2Σg +), N2(B3Пg - A3Σu +) and N2(C3Пu - B3Пg). However, it had little effect on the long-lifetime chemiluminescence, which mainly comes from reactions such as N2(A3Σu +) + N2(A3Σu +) → N2(X1Σg +, v = 0) + N2(B3Пg). A possible explanation of this phenomenon is given, and this phenomenon might have potential applications in instantaneous one-dimensional measurements of various species in gas flow fields.

17.
Opt Express ; 27(3): 2159-2169, 2019 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-30732257

RESUMO

Equivalence ratio is one of the most significant parameters in combustion flow fields. In this paper, femtosecond laser-induced plasma spectroscopy (FLIPS) technique for instantaneous one-dimensional local equivalence ratio measurements were performed. By measuring the spatially resolved spectra of FLIPS, we found that the spectral peak area ratios of CH (431 nm)/N2 (337 nm), CH (431 nm)/N2 (357 nm), and CH (431 nm)/O (777 nm) can be utilized to achieve one-dimensional local equivalence ratio measurements. Among them, the CH peak at ~431 nm and the O peak at ~777 nm are strong enough to be used to achieve single-shot measurements, which is important to turbulent flow fields. Furthermore, systematic experiments were performed by using FLIPS in both laminar and turbulent flow fields. The FLIPS technique features the abilities of instantaneous one-dimensional quantitative measurements, high spatial resolution, and no Bremsstrahlung interference.

18.
Nanotechnology ; 30(10): 105705, 2019 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-30524007

RESUMO

There is now the opportunity for nanomaterials to be utilized in bioapplications with low toxicity, good stability and fine dissolvability. Herein, we present a pulsed laser assisted carbon coating method for nanocrystals, and gadolinium carbide/carbon shell (GC/CS) dots with a face-centered cubic structured gadolinium carbide core that have been synthesized in toluene. Good stability of the GC/CS dots was observed, not only in ethanol but also in the immunoconjugates. The MTT assay revealed immunoconjugates with non/low cytotoxicities. As a type of paramagnetic species, the GC/CS dots revealed excellent enhancement in magnetic resonance imaging at a high magnetic field of 14.1 T at ultra-low concentrations. In terms of the relaxivity values of the 1-3 nm GC/CS sample, both [Formula: see text] and [Formula: see text] have been dramatically increased to 86.5 mM-1 s-1 and 107.3 mM-1 s-1, respectively, thereby demonstrating the great potential for GC/CS dots to be utilized as advanced magnetic resonance agents for the diagnosis of cancers.

19.
Drug Des Devel Ther ; 12: 3357-3368, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30349190

RESUMO

BACKGROUND: Tyroserleutide (YSL) inhibits the growth and metastasis of human hepatocellular carcinoma (HCC). This paper studied the effect of YSL on metastasis of human HCC and investigated its mechanisms. METHODS: In vivo, experimental lung metastasis models of human HCC SK-HEP-1 cells in nude mice were established, and In vitro, the proliferation, adhesion and invasion of SK-HEP-1 cells were detected. RESULTS: In vivo, YSL significantly inhibited the metastasis of human HCC. In vitro, YSL significantly inhibited the proliferation, adhesion and invasion of SK-HEP-1 cells. Through analyses with reverse transcription PCR (RT-PCR) and Western blot, we observed that YSL significantly inhibited the expressions of ICAM-1 in SK-HEP-1 cells. Through RT-PCR, Western blot and zymography methods, YSL was discovered to decrease the mRNA level, protein expression and activity of MMP-2 and -9 in SK-HEP-1 cells. CONCLUSION: We concluded that YSL could inhibit tumor growth and metastasis of human HCC SK-HEP-1 cells.


Assuntos
Carcinoma Hepatocelular/patologia , Molécula 1 de Adesão Intercelular/metabolismo , Neoplasias Hepáticas/patologia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/secundário , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Oligopeptídeos/farmacologia , Animais , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/metabolismo , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Células HEK293 , Humanos , Molécula 1 de Adesão Intercelular/genética , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/metabolismo , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 9 da Matriz/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Oligopeptídeos/administração & dosagem , Oligopeptídeos/uso terapêutico , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Relação Estrutura-Atividade
20.
Opt Express ; 26(16): 21132-21140, 2018 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-30119417

RESUMO

We demonstrate a non-contact spatiotemporally resolved comprehensive method for gas flow velocity field measurement: Filamentary Anemometry using femtosecond Laser-extended Electric Discharge (FALED). A faint thin plasma channel was generated in ambient air by focusing an 800-nm laser beam of 45 fs, which was used to ignite a pulsed electric discharge between two electrodes separated over 10 mm. The power supplier provided a maximum voltage up to 5 kV and was operated at a burst mode with a current duration of less than 20 ns and a pulse-to-pulse separation of 40 µs. The laser-guided thin filamentary discharge plasma column was blowing up perpendicularly by an air jet placed beneath in-between the two electrodes. Although the discharge pulse was short, the conductivity of the plasma channel was observed to sustain much longer, so that a sequence of discharge filaments was generated as the plasma channel being blown up by the jet flow. The sequential bright thin discharge filaments can be photographed using a household camera to calculate the flow velocity distribution of the jet flow. For a direct comparison, a flow field measurement using FLEET [Appl. Opt. 50, 5158 (2011)] was also performed. The results indicate that the FALED technique can provide instantaneous nonintrusive flow field velocity measurement with good accuracy.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA