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1.
Neuroimage ; 293: 120624, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38657745

RESUMEN

Pain empathy, defined as the ability of one person to understand another person's pain, shows large individual variations. The anterior insula is the core region of the pain empathy network. However, the relationship between white matter (WM) properties of the fiber tracts connecting the anterior insula with other cortical regions and an individual's ability to modulate pain empathy remains largely unclear. In this study, we outline an automatic seed-based fiber streamline (sFS) analysis method and multivariate pattern analysis (MVPA) to predict the levels of pain empathy in healthy women and women with primary dysmenorrhoea (PDM). Using the sFS method, the anterior insula-based fiber tract network was divided into five fiber cluster groups. In healthy women, interindividual differences in pain empathy were predicted only by the WM properties of the five fiber cluster groups, suggesting that interindividual differences in pain empathy may rely on the connectivity of the anterior insula-based fiber tract network. In women with PDM, pain empathy could be predicted by a single cluster group. The mean WM properties along the anterior insular-rostroventral area of the inferior parietal lobule further mediated the effect of pain on empathy in patients with PDM. Our results suggest that chronic periodic pain may lead to maladaptive plastic changes, which could further impair empathy by making women with PDM feel more pain when they see other people experiencing pain. Our study also addresses an important gap in the analysis of the microstructural characteristics of seed-based fiber tract network.


Asunto(s)
Dismenorrea , Empatía , Individualidad , Corteza Insular , Sustancia Blanca , Humanos , Femenino , Dismenorrea/diagnóstico por imagen , Dismenorrea/fisiopatología , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Empatía/fisiología , Adulto , Adulto Joven , Corteza Insular/diagnóstico por imagen , Imagen de Difusión Tensora/métodos , Dolor/psicología , Dolor/fisiopatología , Dolor/diagnóstico por imagen , Vías Nerviosas/diagnóstico por imagen , Vías Nerviosas/fisiopatología , Imagen por Resonancia Magnética , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/fisiopatología , Corteza Cerebral/diagnóstico por imagen
2.
Small ; : e2404228, 2024 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-39075930

RESUMEN

Few-layer tin (Sn)-based nanosheets (NSs) with a thickness of ≈2.5 nm are successfully prepared using a modified liquid phase exfoliation (LPE) method. Here the first exploration of photo-electrochemical (PEC) and nonlinear properties of Sn NSs is presented. The results demonstrate that the PEC properties are tunable under different experimental conditions. Additionally, Sn NSs are shown to exhibit a unique self-powered PEC performance, maintaining a good long-term stability for up to 1 month. Using electron spin resonance, active species, such as hydroxyl radicals (·OH), superoxide radicals (·O2 -), and holes (h+), are detected during operations, providing a deeper understanding of the working mechanism. Furthermore, measurements of nonlinear response reveal that Sn NSs can be effective for all-optical modulation, as it enables the realization of all-optical switching through excitation spatial cross-phase modulation (SXPM). These findings present new research insights and potential applications of Sn NSs in optoelectronics.

3.
Opt Lett ; 49(7): 1798-1801, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38560866

RESUMEN

Vectorial holography through a strongly scattering medium can facilitate various applications in optics and photonics. However, the realization of vectorial holography with arbitrary distribution of optical intensity is still limited because of experimental noise during the calibration of vectorial transmission matrix (TM) and reconstruction noise during the retrieval of input wavefront for a given holographic target. Herein, we propose and experimentally demonstrate the vectorial holography with arbitrary distribution of optical intensity over a multimode fiber (MMF) using the Tikhonov regularization. By optimizing the noise factor, the performance of vectorial holography over an MMF is improved compared with the conjugate transpose and inverse TM methods. Our results might shed new light on the optical communication and detection mediated by MMFs.

4.
FASEB J ; 37(6): e22942, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37178006

RESUMEN

Extracellular vesicles (EVs) possess great potential in the modulation of cardiovascular diseases. Our current work intended to assay the clinical significance of endothelial cell (EC)-derived EVs in atherosclerosis (AS). Expression of HIF1A-AS2, miR-455-5p, and ESRRG in plasma from AS patients and mice and EVs from ox-LDL-treated ECs was measured. Interactions among HIF1A-AS2, miR-455-5p, ESRRG, and NLRP3 were analyzed. Next, EVs were co-cultured with ECs, and ectopic expression and depletion experimentations of HIF1A-AS2, miR-455-5p, ESRRG, and/or NLRP3 were carried out to assay their roles in pyroptosis and inflammation of ECs in AS. At last, the effects of HIF1A-AS2 shuttled by EC-derived EVs on EC pyroptosis and vascular inflammation in AS were verified in vivo. HIF1A-AS2 and ESRRG were highly expressed, while miR-455-5p was poorly expressed in AS. HIF1A-AS2 could sponge miR-455-5p to elevate the expression of ESRRG and NLRP3. Both in vitro and in vivo experiments revealed that ECs-derived EVs carrying HIF1A-AS2 induced the pyroptosis and vascular inflammation of ECs to promote the progression of AS by sponging miR-455-5p via ESRRG/NLRP3. HIF1A-AS2 shuttled by ECs-derived EVs can accelerate the progression of AS by downregulating miR-455-5p and upregulating ESRRG and NLRP3.


Asunto(s)
Aterosclerosis , Vesículas Extracelulares , MicroARNs , Ratones , Animales , MicroARNs/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Piroptosis , Células Endoteliales/metabolismo , Inflamación/metabolismo , Aterosclerosis/metabolismo , Vesículas Extracelulares/metabolismo
5.
Hepatology ; 75(5): 1218-1234, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-34591986

RESUMEN

BACKGROUND AND AIMS: NAFLD is considered as the hepatic manifestation of the metabolic syndrome, which includes insulin resistance, obesity and hyperlipidemia. NASH is a progressive stage of NAFLD with severe hepatic steatosis, hepatocyte death, inflammation, and fibrosis. Currently, no pharmacological interventions specifically tailored for NASH are approved. Ovarian tumor domain, ubiquitin aldehyde binding 1 (OTUB1), the founding member of deubiquitinases, regulates many metabolism-associated signaling pathways. However, the role of OTUB1 in NASH is unclarified. METHODS AND RESULTS: We demonstrated that mice with Otub1 deficiency exhibited aggravated high-fat diet-induced and high-fat high-cholesterol (HFHC) diet-induced hyperinsulinemia and liver steatosis. Notably, hepatocyte-specific overexpression of Otub1 markedly alleviated HFHC diet-induced hepatic steatosis, inflammatory responses, and liver fibrosis. Mechanistically, we identified apoptosis signal-regulating kinase 1 (ASK1) as a key candidate target of OTUB1 through RNA-sequencing analysis and immunoblot analysis. Through immunoprecipitation-mass spectrometry analysis, we further found that OTUB1 directly bound to tumor necrosis factor receptor-associated factor 6 (TRAF6) and suppressed its lysine 63-linked polyubiquitination, thus inhibiting the activation of ASK1 and its downstream pathway. CONCLUSIONS: OTUB1 is a key suppressor of NASH that inhibits polyubiquitinations of TRAF6 and attenuated TRAF6-mediated ASK1 activation. Targeting the OTUB1-TRAF6-ASK1 axis may be a promising therapeutic strategy for NASH.


Asunto(s)
Cisteína Endopeptidasas/metabolismo , Enfermedad del Hígado Graso no Alcohólico , Animales , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Hígado , Ratones , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , Transducción de Señal , Factor 6 Asociado a Receptor de TNF
6.
Opt Express ; 30(23): 42415-42428, 2022 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-36366696

RESUMEN

Optical biosensor, which perceptively captures the variety of refractive index (RI) of the surrounding environment, has great potential applications in detecting property changes and types of analytes. However, the disequilibrium of light-matter interaction in different polarizations lead to the polarization-dependence and low sensitivity. Here, we propose a polarization-independent and ultrasensitive biosensor by introducing a one-dimensional topological photonic crystal (1D TPhC), where two N-period 1D photonic crystals (PhC1 and PhC2) with different topological invariants are designed for compressing the interaction region of the optical fields, and enhancing the interaction between the light and analyte. Since the strong light-matter interaction caused by the band-inversion is polarization-independent, the biosensor can obtain superior sensing performance both for TE and TM polarization modes. The sensitivity and Figure of Merit (FOM) of the designed biosensor are 1.5677×106 RIU-1 (1.3497 × 106 RIU-1) and 7.8387×1010 RIU-1deg-1 (4.4990×1010 RIU-1deg-1) for TM (TE) polarization mode, which performs two orders of magnitude enhancement compared with the reported biosensors. With the protection of the topological edge state, this biosensor has high tolerance to the thickness deviations and refractive index (RI) variations of the component materials, which can reduce the requirements on fabrication and working environment. It is anticipated that the proposed biosensor possesses excellent sensing performances, may have great potentials in environmental monitoring, medical detection, etc.


Asunto(s)
Técnicas Biosensibles , Fotones , Óptica y Fotónica , Refractometría
7.
J Nat Prod ; 85(7): 1808-1815, 2022 07 22.
Artículo en Inglés | MEDLINE | ID: mdl-35796002

RESUMEN

Two new 3,4-epoxy group-containing abietane diterpenoids (1 and 2), together with five known diterpenoids (3-7), were isolated from Ajuga decumbens. Their structures were elucidated by spectroscopic data analysis, NMR calculations, and X-ray diffraction experiments. The structures of two known abietane diterpenoids were revised based on NMR calculations and X-ray diffraction data. Notably, compound 4 specifically inhibited RSL3-induced ferroptosis with an EC50 of 56 nM by antioxidation. Moreover, 4 significantly decreased RSL3-induced lipid and cytosolic ROS accumulation and ferroptosis marker gene PTGS2 mRNA expression. This work reports the most potent natural inhibitor against ferroptosis found so far.


Asunto(s)
Ajuga , Diterpenos , Ferroptosis , Abietanos/química , Abietanos/farmacología , Diterpenos/química , Diterpenos/farmacología , Espectroscopía de Resonancia Magnética , Estructura Molecular
8.
J Integr Plant Biol ; 64(11): 2033-2038, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36047457

RESUMEN

Knowledge of the transcription factor binding landscape (TFBL) is necessary to analyze gene regulatory networks for important agronomic traits. However, a low-cost and high-throughput in vivo chromatin profiling method is still lacking in plants. Here, we developed a transient and simplified cleavage under targets and tagmentation (tsCUT&Tag) that combines transient expression of transcription factor proteins in protoplasts with a simplified CUT&Tag without nucleus extraction. Our tsCUT&Tag method provided higher data quality and signal resolution with lower sequencing depth compared with traditional ChIP-seq. Furthermore, we developed a strategy combining tsCUT&Tag with machine learning, which has great potential for profiling the TFBL across plant development.


Asunto(s)
Cromatina , Factores de Transcripción , Sitios de Unión , Análisis Costo-Beneficio , Unión Proteica , Factores de Transcripción/metabolismo , Secuenciación de Nucleótidos de Alto Rendimiento
9.
Opt Express ; 29(11): 17602-17612, 2021 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-34154300

RESUMEN

Lossy-mode-resonance (LMR) is a surface plasmon resonance (SPR)-analogue optical phenomenon, which is sensitive to the surrounding environment variations and can be considered as an important detection signal in biochemical sensors. Compared with the SPR sensor which can only operate under transverse magnetic (TM)-polarized light, the LMR sensor shows a more excellent application prospect and can operate in both TM- and transverse electric (TE)-polarized light. In this work, a CH3NH3PbBr3-based LMR configuration is proposed to apply in optical sensors. When the incident light is in TM mode, the preferred way to improve the performance of the LMR sensor is optimizing the thickness of the matching layer, and the highest sensitivity of 11382 refractive index unit (RIU-1) is achieved, which is more than 200 times larger than that of the conventional Au-based SPR sensor; when the incident light is in TE mode, it is more advantageous to improve the properties of LMR sensor by optimizing the thickness of CH3NH3PbBr3 layer, and a high sensitivity of 21697 RIU-1 is obtained. With such high sensitivity, we believe that the CH3NH3PbBr3-based LMR sensor will find potential applications in biology, medicine, chemistry and other fields.

10.
J Cell Physiol ; 235(3): 2149-2160, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31389030

RESUMEN

miR-222 participates in many cardiovascular diseases, but its effect on cardiac remodeling induced by diabetes is unclear. This study evaluated the functional role of miR-222 in cardiac fibrosis in diabetic mice. Streptozotocin (STZ) was used to establish a type 1 diabetic mouse model. After 10 weeks of STZ injection, mice were intravenously injected with Ad-miR-222 to induce the overexpression of miR-222. miR-222 overexpression reduced cardiac fibrosis and improved cardiac function in diabetic mice. Mechanistically, miR-222 inhibited the endothelium to mesenchymal transition (EndMT) in diabetic mouse hearts. Mouse heart fibroblasts and endothelial cells were isolated and cultured with high glucose (HG). An miR-222 mimic did not affect HG-induced fibroblast activation and function but did suppress the HG-induced EndMT process. The antagonism of miR-222 by antagomir inhibited HG-induced EndMT. miR-222 regulated the promoter region of ß-catenin, thus negatively regulating the Wnt/ß-catenin pathway, which was confirmed by ß-catenin siRNA. Taken together, our results indicated that miR-222 inhibited cardiac fibrosis in diabetic mice via negatively regulating Wnt/ß-catenin-mediated EndMT.


Asunto(s)
Diabetes Mellitus Experimental/genética , Endotelio/patología , Transición Epitelial-Mesenquimal/genética , Fibrosis/genética , MicroARNs/genética , Vía de Señalización Wnt/genética , beta Catenina/genética , Animales , Células Endoteliales/patología , Fibrosis/patología , Glucosa/genética , Corazón , Masculino , Ratones , Ratones Endogámicos C57BL , ARN Interferente Pequeño/genética , Estreptozocina/farmacología
11.
Small ; 16(35): e2002252, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32734683

RESUMEN

Optical nonlinearity in 2D materials excited by spatial Gaussian laser beam is a novel and peculiar optical phenomenon, which exhibits many novel and interesting applications in optical nonlinear devices. Passive photonic devices, such as optical switches, optical logical gates, photonic diodes, and optical modulators, are the key compositions in the future all-optical signal-processing technologies. Passive photonic devices using 2D materials to achieve the device functionality have attracted widespread concern in the past decade. In this Review, an overview of the spatial self-phase modulation (SSPM) in 2D materials is summarized, including the operating mechanism, optical parameter measurement, and tuning for 2D materials, and applications in photonic devices. Moreover, some current challenges are also proposed to solve, and some possible applications of SSPM method are predicted for the future. Therefore, it is anticipated that this summary can contribute to the application of 2D material-based spatial effect in all-optical signal-processing technologies.

12.
Hepatology ; 70(4): 1099-1118, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-30820969

RESUMEN

Nonalcoholic fatty liver disease (NAFLD) has become the most common cause of chronic liver disease worldwide. Due to the growing economic burden of NAFLD on public health, it has become an emergent target for clinical intervention. DUSP12 is a member of the dual specificity phosphatase (DUSP) family, which plays important roles in brown adipocyte differentiation, microbial infection, and cardiac hypertrophy. However, the role of DUSP12 in NAFLD has yet to be clarified. Here, we reveal that DUSP12 protects against hepatic steatosis and inflammation in L02 cells after palmitic acid/oleic acid treatment. We demonstrate that hepatocyte specific DUSP12-deficient mice exhibit high-fat diet (HFD)-induced and high-fat high-cholesterol diet-induced hyperinsulinemia and liver steatosis and decreased insulin sensitivity. Consistently, DUSP12 overexpression in hepatocyte could reduce HFD-induced hepatic steatosis, insulin resistance, and inflammation. At the molecular level, steatosis in the absence of DUSP12 was characterized by elevated apoptosis signal-regulating kinase 1 (ASK1), which mediates the mitogen-activated protein kinase (MAPK) pathway and hepatic metabolism. DUSP12 physically binds to ASK1, promotes its dephosphorylation, and inhibits its action on ASK1-related proteins, JUN N-terminal kinase, and p38 MAPK in order to inhibit lipogenesis under high-fat conditions. Conclusion: DUSP12 acts as a positive regulator in hepatic steatosis and offers potential therapeutic opportunities for NAFLD.


Asunto(s)
Apoptosis/genética , Fosfatasas de Especificidad Dual/genética , Regulación de la Expresión Génica , MAP Quinasa Quinasa Quinasa 5/genética , Enfermedad del Hígado Graso no Alcohólico/genética , Análisis de Varianza , Animales , Células Cultivadas , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Regulación hacia Abajo , Humanos , Resistencia a la Insulina/genética , Metabolismo de los Lípidos/genética , Lipogénesis/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Enfermedad del Hígado Graso no Alcohólico/fisiopatología , Distribución Aleatoria , Valores de Referencia , Transducción de Señal/genética
13.
Plant Mol Biol ; 101(4-5): 389-401, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31432304

RESUMEN

KEY MESSAGE: Overexpression of cotton cellulose synthase like D3 (GhCSLD3) gene partially rescued growth defect of atcesa6 mutant with restored cell elongation and cell wall integrity mainly by enhancing primary cellulose production. Among cellulose synthase like (CSL) family proteins, CSLDs share the highest sequence similarity to cellulose synthase (CESA) proteins. Although CSLD proteins have been implicated to participate in the synthesis of carbohydrate-based polymers (cellulose, pectins and hemicelluloses), and therefore plant cell wall formation, the exact biochemical function of CSLD proteins remains controversial and the function of the remaining CSLD genes in other species have not been determined. In this study, we attempted to illustrate the function of CSLD proteins by overexpressing Arabidopsis AtCSLD2, -3, -5 and cotton GhCSLD3 genes in the atcesa6 mutant, which has a background that is defective for primary cell wall cellulose synthesis in Arabidopsis. We found that GhCSLD3 overexpression partially rescued the growth defect of the atcesa6 mutant during early vegetative growth. Despite the atceas6 mutant having significantly reduced cellulose contents, the defected cell walls and lower dry mass, GhCSLD3 overexpression largely restored cell wall integrity (CWI) and improved the biomass yield. Our result suggests that overexpression of the GhCSLD protein enhances primary cell wall synthesis and compensates for the loss of CESAs, which is required for cellulose production, therefore rescuing defects in cell elongation and CWI.


Asunto(s)
Arabidopsis/crecimiento & desarrollo , Gossypium/genética , Proteínas de Plantas/fisiología , Arabidopsis/genética , Arabidopsis/metabolismo , Pared Celular/metabolismo , Celulosa/biosíntesis , Celulosa/genética , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/crecimiento & desarrollo , Plantas Modificadas Genéticamente/metabolismo
14.
Small ; 15(47): e1903233, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31609534

RESUMEN

Van der Waals (vdW)-integrated heterojunctions have been widely investigated in optoelectronics due to their superior photoelectric conversion capability. In this work, 0D bismuth quantum dots (Bi QDs)-decorated 1D tellurium nanotubes (Te NTs) vdW heterojunctions (Te@Bi vdWHs) are constructed by a facile bottom-up assembly process. Transient absorption spectroscopy suggests that Te@Bi vdWH is a promising candidate for new-generation optoelectronic devices with fast response properties. The subsequent experiments and density functional theory calculations demonstrate the vdW interaction between Te NTs and Bi QDs, as well as the enhanced optoelectronic characteristics owing to the plasma effects at the interface between Te NTs and Bi QDs. Moreover, Te@Bi vdWHs-based photodetectors show significantly improved photoresponse behavior in the ultraviolet region compared to pristine Te NTs or Bi QDs-based photodetectors. The proposed integration of vdWHs is expected to pave the way for constructing new nanoscale heterodevices.

15.
Small ; 15(23): e1900902, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31016874

RESUMEN

Non-layered tellurium (Te) is a promising material for applications in transistor and optoelectronic devices for its advantages in excellent intrinsic electronic and optoelectronic properties. However, the poor photodetection performance and relatively uncertain stability of tellurene under ambient conditions greatly limit the practical applications. In order to improve the performance of tellurene-based materials, Te@Se roll-to-roll nanotubes with different selenium (Se) contents synthesized by epitaxial growth of Se on Te nanotubes are, for the first time, employed to fabricate working electrodes for photoelectrochemical (PEC)-type broadband photodetection. They exhibit not only a preferably enhanced capacity for self-powered broadband photodetection but also significantly improved photocurrent density and stability in various aqueous environments (HCl, NaCl, and KOH solutions), compared to tellurene-based photodetectors. It is anticipated that the present work can open up new possibilities for high-performance tellurene-based optoelectronic devices.

16.
Exp Cell Res ; 370(1): 78-86, 2018 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-29902536

RESUMEN

Metabolic dysfunction is a hallmark of cardiac hypertrophy and heart failure. During cardiac failure, the metabolism of cardiomyocyte switches from fatty acid oxidation to glycolysis. However, the roles of key metabolic enzymes in cardiac hypertrophy are not understood fully. Here in the present work, we identified Aldolase A (AldoA) as a core regulator of cardiac hypertrophy. The mRNA and protein levels of AldoA were significantly up-regulated in transverse aortic constriction (TAC)- and isoproterenol (ISO)-induced hypertrophic mouse hearts. Overexpression of AldoA in cardiomyocytes promoted ISO-induced cardiomyocyte hypertrophy, whereas AldoA knockdown repressed cardiomyocyte hypertrophy. In addition, adeno-associated virus 9 (AAV9)-mediated in vivo knockdown of AldoA in the hearts rescued ISO-induced decrease in cardiac ejection fraction and fractional shortening and repressed cardiac hypertrophy. Mechanism study revealed that AldoA repressed the activation of AMP-dependent protein kinase (AMPK) signaling in a liver kinase B1 (LKB1)-dependent and AMP-independent manner. Inactivation of AMPK is a core mechanism underlying AldoA-mediated promotion of ISO-induced cardiomyocyte hypertrophy. By contrast, activation of AMPK with metformin and AICAR blocked AldoA function during cardiomyocyte hypertrophy. In summary, our data support the notion that AldoA-AMPK axis is a core regulatory signaling sensing energetic status and participates in cardiac hypertrophy.


Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Cardiomegalia/metabolismo , Cardiomegalia/patología , Fructosa-Bifosfato Aldolasa/metabolismo , Transducción de Señal/fisiología , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/metabolismo , Animales , Corazón/fisiopatología , Insuficiencia Cardíaca/metabolismo , Insuficiencia Cardíaca/patología , Masculino , Ratones , Miocardio/metabolismo , Miocardio/patología , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Proteínas Serina-Treonina Quinasas/metabolismo , Ribonucleótidos/metabolismo , Regulación hacia Arriba/fisiología
17.
Opt Express ; 26(5): 5488-5496, 2018 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-29529751

RESUMEN

Black phosphorus (BP), a promising new two-dimensional (2D) material, has drawn a lot of attentions in academia and industry due to its extraordinary physical and chemical properties. In this paper, we theoretically demonstrate a monolayer BP that achieves coherent perfect absorption (CPA) at the THz/infrared band. It is found that quasi-CPA point does exist at the THz/infrared band. The CPA, which has a relative bandwidth of 141.3% and a coherent absorptivity of more than 90%, can be implemented at the quasi-CPA wavelength through a proper phase modulation. Moreover, the coherent absorptivity can be modulated with a high modulation depth by means of the phase difference between the two coherent counter-propagating beams. The angular selectivity of the monolayer BP is also investigated. The CPA wavelength is divided into two wavelength branches for TE and TM polarization at oblique incidence. In addition, the CPA wavelength can be tuned from THz to infrared band by adjusting the electron doping of the BP while maintaining the modulation depth of 104. Hence, our results may be potentially used for coherent modulations in terahertz/infrared detections and signal processing with 2D materials.

18.
Opt Express ; 26(13): 16884-16892, 2018 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-30119507

RESUMEN

Fano resonance is realized in the multilayer structure consisting of two planar waveguides (PWGs) and few layer graphene, and the coupling mechanism between the two PWG modes with graphene is analyzed in detail. It is revealed that the Fano resonance originates from the different quality factors due to the different intrinsic losses of the graphene in the two waveguides, and the electric field distributions in the multilayer structure confirms our results. Fano resonance in our proposed structures can be applied in the ultrasensitive biosensor, and a significantly improved figure of merit (FOM) of 9340 RIU-1 has been obtained by optimizing the structure parameters, which has a 2~3 orders of magnitude enhancement compared to the traditional surface plasmon polaritons (SPR) sensor. Especially, it is found that both transverse magnetic (TM)-polarization and transverse electric (TE)-polarization can support the Fano resonance, and hence it can work as ultrasensitive biosensor for both polarizations.

19.
Opt Lett ; 43(17): 4256-4259, 2018 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-30160765

RESUMEN

The topological edge mode, which exists at the interface of a one-dimensional (1D) topological photonic crystal (PhC) heterostructure, provides the possibility to realize perfect absorption for its strong field localization effects. In this Letter, it is found that a huge absorption enhancement appears because of the excitation of topological edge mode, while the graphene is sandwiched between two 1D PhCs. The single peak perfect absorption is realized by means of the strong coupling of incident light and Tamm plasmon polaritons (TPPs) which is excited with Ag-PhC structure. Moreover, we use a heterostructure constructed by two PhCs, a monolayer graphene and Ag mirror to theoretically demonstrate that multi-channel perfect absorption can be achieved based on the effect of topological edge mode, TPPs and critical coupling. The angular selectivity of the proposed absorber is also investigated. Both of the absorption peaks are extremely narrow, and the absorption can be maintained more than 97% with the incident angle varying from 0° to 50°. Hence, our results may have potential applications in optical switches, thermal emissions, and narrowband selective filters.

20.
Sensors (Basel) ; 18(12)2018 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-30558226

RESUMEN

Surface exciton polaritons (SEPs) are one of the three major elementary excitations: Phonons, plasmons and excitons. They propagate along the interface of the crystal and dielectric medium. Surface exciton polaritons hold a significant position in the aspect of novel sensor and optical devices. In this article, we have realized a sharp Fano resonance (FR) by coupling the planar waveguide mode (WGM) and SEP mode with Cytop (perfluoro (1-butenyl vinyl ether)) and J-aggregate cyanine dye. After analyzing the coupling mechanism and the localized field enhancement, we then applied our structure to the imaging biosensor. It was shown that the maximum imaging sensitivity of this sensor could be as high as 5858 RIU-1, which is more than three times as much as classical FR based on metal. A biosensor with ultra-high sensitivity, simple manufacturing technique and lower cost with J-aggregate cyanine dye provides us with the most appropriate substitute for the surface plasmon resonance sensors with the noble metals and paves the way for applications in new sensing technology and biological studies.


Asunto(s)
Técnicas Biosensibles/métodos , Nanopartículas del Metal/química
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