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1.
Magn Reson Imaging ; 109: 203-210, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38513788

RESUMEN

PURPOSE: To determine the usefulness of multiparametric magnetic resonance (MR) quantitative imaging in characterizing the kidneys in systemic sclerosis (SSc) patients. MATERIAL AND METHODS: Forty-six SSc patients (47.9 ± 12.8 years, 40 females) and 22 age- and sex- matched healthy volunteers (46.1 ± 13.8 years, 20 females) were recruited and underwent renal MR imaging by acquiring blood oxygen level dependent and saturated multi-delay renal arterial spin labeling (SAMURAI) sequences. The T2* value, T1 value, renal blood flow (RBF), arterial bolus arrival time (aBAT), and tissue bolus arrival time (tBAT) of renal cortex were measured and compared among diffuse cutaneous SSc (dcSSc) and limited cutaneous SSc (lcSSc) groups and healthy controls using One-way ANOVA and analyzed by logistic regression. RESULTS: Compared to healthy volunteers, SSc patients with normal estimated glomerular filtration rate (n = 40) had significantly lower T2* value (P = 0.026) in the left renal cortex, longer T1 value (right: P = 0.015; left: P = 0.023), lower RBF (right: P < 0.001; left: P < 0.001), and shorter tBAT (right: P < 0.001; left: P = 0.005) in both right and left renal cortex after adjusting for demographics. The dcSSc patients (n = 23) had significantly lower RBF in both right (226.7 ± 65.2 mL/100 g/min vs. 278.2 ± 73.5 mL/100 g/min, P = 0.022) and left (194.5 ± 71.5 mL/100 g/min vs. 252.7 ± 84.4 mL/100 g/min, P = 0.020) renal cortex compared to the lcSSc patients (n = 23) after adjusting for demographics, but the significance of the difference was attenuated after further adjusting for modified Rodnan skin score and digital ulcers. CONCLUSION: Multi-parametric MR quantitative imaging, particularly multi-delay ASL perfusion imaging, is a useful technique for characterizing the kidneys and classification of SSc patients.


Asunto(s)
Esclerodermia Sistémica , Úlcera Cutánea , Femenino , Humanos , Esclerodermia Sistémica/diagnóstico por imagen , Riñón/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética
2.
RMD Open ; 9(4)2023 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-38088247

RESUMEN

BACKGROUND: Systemic sclerosis (SSc) is characterised by microvascular and fibrotic lesions, which are located not only in skin but also in lungs and heart. OBJECTIVE: This study aimed to investigate the association between lung function and myocardial T1 values using cardiac MR (CMR) imaging in patients with SSc without cardiovascular symptoms. METHODS: The SSc patients and age- and sex-matched healthy subjects underwent CMR. The cardiac function and native T1 values of myocardium and lung function were measured. Spearman's rank correlations and linear regression analyses were performed to determine the association between lung function and myocardial T1. RESULTS: Forty-five SSc patients (aged 47.7±13.2 years, 40 females) and 23 (aged 46.0±14.4 years, 20 females) healthy subjects were enrolled. SSc patients exhibited considerably higher native T1 values compared with healthy subjects (1305.9±49.8 ms vs 1272.6±37.6 ms, p=0.006). Linear regression analysis revealed that decrease of diffusing capacity of lungs for carbon monoxide (DLCO) in SSc patients was notably associated with myocardial native T1 value before (ß -1.017; 95% CI -1.883 to -0.151; p=0.022) and after adjusting for confounding factors (ß -1.108; 95% CI -2.053 to -0.164; p=0.023). Moderate-to-severe decrease of DLCO was found to be significantly associated with myocardial native T1 value (ß 48.006; 95% CI 17.822 to 78.190; p=0.003) after adjusting for confounding factors. CONCLUSION: DLCO inversely correlates with myocardial native T1 values in SSc patients, particularly moderate-to-severely decreased DLCO, suggesting that DLCO might be a potential indicator for subclinical myocardial impairment in SSc patients.


Asunto(s)
Hipertensión Pulmonar , Esclerodermia Sistémica , Femenino , Humanos , Monóxido de Carbono , Hipertensión Pulmonar/complicaciones , Hipertensión Pulmonar/diagnóstico , Pulmón/diagnóstico por imagen , Esclerodermia Sistémica/complicaciones , Esclerodermia Sistémica/diagnóstico , Miocardio
3.
Immun Inflamm Dis ; 11(12): e1124, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38156383

RESUMEN

High-mobility group box 1 (HMGB1) is a highly conserved nonhistone nuclear protein found in the calf thymus and participates in a variety of intracellular processes such as DNA transcription, replication and repair. In the cytoplasm, HMGB1 promotes mitochondrial autophagy and is involved in in cellular stress response. Once released into the extracellular, HMGB1 becomes an inflammatory factor that triggers inflammatory responses and a variety of immune responses. In addition, HMGB1 binding with the corresponding receptor can activate the downstream substrate to carry out several biological effects. Meanwhile, HMGB1 is involved in various signaling pathways, such as the HMGB1/RAGE pathway, HMGB1/NF-κB pathway, and HMGB1/JAK/STAT pathway, which ultimately promote inflammation. Moreover, HMGB1 may be involved in the pathogenesis of asthma by regulating downstream signaling pathways through corresponding receptors and mediates a number of signaling pathways in asthma, such as HMGB1/TLR4/NF-κB, HMGB1/RAGE, HMGB1/TGF-ß, and so forth. Accordingly, HMGB1 emerges as a therapeutic target for asthma.


Asunto(s)
Asma , Proteína HMGB1 , Humanos , FN-kappa B/metabolismo , Transducción de Señal , Proteína HMGB1/genética , Proteína HMGB1/metabolismo , Quinasas Janus/metabolismo , Factores de Transcripción STAT/metabolismo , Asma/tratamiento farmacológico , Asma/patología
4.
Ther Adv Respir Dis ; 17: 17534666231208628, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37947059

RESUMEN

Ferroptosis is a regulatory cell death characterized by intracellular iron accumulation and lipid peroxidation that leads to oxidative stress. Many signaling pathways such as iron metabolism, lipid metabolism, and amino acid metabolism precisely regulate the process of ferroptosis. Ferroptosis is involved in a variety of lung diseases, such as acute lung injury, chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis. Increasing studies suggest that ferroptosis is involved in the development of asthma. Ferroptosis plays an important role in asthma. Iron metabolism disorders, lipid peroxidation, amino acid metabolism disorders lead to the occurrence of ferroptosis in airway epithelial cells, and then aggravate clinical symptoms in asthmatic patients. Moreover, several regulators of ferroptosis are involved in the pathogenesis of asthma, such as Nrf2, heme oxygenase-1, mevalonate pathway, and ferroptosis inhibitor protein 1. Importantly, ferroptosis inhibitors improve asthma. Thus, the pathogenesis of ferroptosis and its contribution to the pathogenesis of asthma help us better understand the occurrence and development of asthma, and provide new directions in asthma treatment. This article aimed to review the role and mechanism of ferroptosis in asthma, describing the relationship between ferroptosis and asthma based on signaling pathways and related regulatory factors. At the same time, we summarized current observations of ferroptosis in eosinophils, airway epithelial cells, and airway smooth muscle cells in asthmatic patients.


Asunto(s)
Asma , Ferroptosis , Humanos , Asma/tratamiento farmacológico , Inflamación , Aminoácidos , Hierro
5.
Cell Mol Neurobiol ; 43(7): 3329-3341, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37458878

RESUMEN

Ferroptosis is a new form of programmed cell death, which is characterized by the iron-dependent accumulation of lipid peroxidation and increase of ROS, resulting in oxidative stress and cell death. Iron, lipid, and multiple signaling pathways precisely control the occurrence and implementation of ferroptosis. The pathways mainly include Nrf2/HO-1 signaling pathway, p62/Keap1/Nrf2 signaling pathway. Activating p62/Keap1/Nrf2 signaling pathway inhibits ferroptosis. Nrf2/HO-1 signaling pathway promotes ferroptosis. Furthermore, some factors also participate in the occurrence of ferroptosis under hypoxia, such as HIF-1, NCOA4, DMT1. Meanwhile, ferroptosis is related with hypoxia-related diseases, such as MIRI, cancers, and AKI. Accordingly, ferroptosis appears to be a therapeutic target for hypoxia-related diseases.


Asunto(s)
Ferroptosis , Humanos , Proteína 1 Asociada A ECH Tipo Kelch , Factor 2 Relacionado con NF-E2 , Hipoxia , Hierro , Especies Reactivas de Oxígeno
6.
Arch Microbiol ; 205(6): 251, 2023 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-37249701

RESUMEN

There is an increasing interest in the use of spore-forming Bacillus spp. as probiotic ingredients on the market. However, probiotics Bacillus species are insufficient, and more safe Bacillus species were required. In the study, traditional fermented foods and soil samples were collected from more than ten provinces in China, and 506 Bacillus were selected from 109 samples. Using the optimized procedure, we screened nine strains, which successfully passed the acid, alkali, bile salt, and trypsin resistance test. Drug sensitivity test results showed that three Bacillus out of the nine isolates exhibited antibiotic sensitivity to more than 29 antibiotics. The three strains sensitive to antibiotics were identified by 16S ribosomal RNA, recA, and gyrB gene analysis, two isolates (38,327 and 38,328) belong to the species Lysinibacillus capsici and one isolate (37,326) belong to Bacillus halotolerans. Moreover, the three strains were confirmed safe through animal experiments. Finally, L. capsici 38,327 and 38,328 showed protections in the Salmonella typhimurium infection mouse model, which slowed down weight loss, reduced bacterial load, and improved antioxidant capacity. Altogether, our data demonstrated that selected L. capsici strains can be used as novel probiotics for intestinal health.


Asunto(s)
Bacillaceae , Probióticos , Animales , Ratones , Suelo , Antibacterianos/farmacología , Bacillaceae/genética , Intestinos , ARN Ribosómico 16S/genética
7.
Orphanet J Rare Dis ; 18(1): 83, 2023 04 14.
Artículo en Inglés | MEDLINE | ID: mdl-37060032

RESUMEN

BACKGROUND: Myocardial involvement (MI) is the primary cause of death in patients with systemic sclerosis (SSc). We analyzed patients with SSc and MI to identify their characteristics and outcome. METHOD: We retrospectively collected data from SSc patients with MI admitted to Peking Union Medical College Hospital between January 2012 and May 2021. SSc patients without MI were randomly selected as controls after matching age and gender at a ratio of 1:3. RESULTS: In total, 21 SSc patients (17 females) with MI were enrolled. The mean age at SSc onset was 42.3 ± 15.1 years old. Compared with controls, myositis (42.9% vs. 14.3%, P = 0.014) and elevation of CK (33.3% vs. 4.8%, P = 0.002) were more common in patients with MI. Of the 7 patients without cardiovascular symptoms, 3 /5 showed elevations in cardiac troponin-I (cTnI), 6 showed elevations of N-terminal brain natriuretic peptide (NT-proBNP). Eleven patients were followed up for a median period of 15.5 months and four patients developed newly occurring left ventricular ejection fraction (LVEF) < 50%. CONCLUSION: One third of SSc patients with MI were asymptomatic. Regular monitoring of CTnI, NT-proBNP and echocardiography is helpful for the diagnosis of MI during the early stages. Its prognosis is poor.


Asunto(s)
Esclerodermia Sistémica , Función Ventricular Izquierda , Femenino , Humanos , Adulto , Persona de Mediana Edad , Volumen Sistólico , Estudios Retrospectivos , Biomarcadores , Pronóstico , Esclerodermia Sistémica/diagnóstico , Fragmentos de Péptidos
8.
Rev Sci Instrum ; 93(12): 123101, 2022 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-36586904

RESUMEN

To prevent the x-ray detectors from the interference of optical photons, x-ray filters are widely used in x-ray space missions. As the flux of low energy x-rays would be significantly attenuated by the filters, it is important to derive the transmittance of the filters below 10 keV. In this paper, we present a simple experimental apparatus and data processing method to measure the transmittance curve of x-ray filters in the energy range from 1.6 to 10 keV. The measured spectra were further processed with Geant4 Monte Carlo simulation results and a direct demodulation algorithm. The obtained transmittance is in good accordance with the theoretical calculation and the synchrotron radiation test result, which proves that the proposed system with the algorithm is a reasonable way to characterize the x-ray transmittance performance of filters above 1.6 keV.

9.
Nanoscale ; 14(48): 17921-17928, 2022 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-36458471

RESUMEN

Metasurfaces can enable polarization multiplexing of light so as to carry more information. Specific polarized light necessitates bulk polarizers and waveplates, which significantly increases the form size of metasurface devices. We propose an electrically programmable metasurface enabled by dual-frequency cholesteric liquid crystals (DF-CLCs) for simultaneous near- and far-field displays. Moreover, the integrated device can be electrically programmed to demonstrate 6 different optical images by engineering the DF-CLCs with frequency-modulated voltage pulses. Such programmable metasurfaces are potentially useful for many applications including information storage, displays, anti-counterfeiting, and so on.

10.
ACS Appl Mater Interfaces ; 14(48): 53981-53989, 2022 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-36378812

RESUMEN

Chirality induction, transfer, and manipulation have aroused great interest in achiral nanomaterials. Here, we demonstrate strong upconverted circularly polarized luminescence from achiral core-shell upconversion nanoparticles (UCNPs) via a plasmonic chiral metasurface-induced optical chirality transfer. The Yb3+-sensitized core-shell UCNPs with good dispersity exhibit intense upconversion luminescence of Tm3+ and Nd3+ through the energy transfer process. By spin-coating the core-shell UCNPs on this chiral metasurface, strong enhancement and circular polarization modulation of upconversion luminescence can be achieved due to resonant coupling between surface plasmons and upconversion nanoparticles. In the UCNPs-on-metasurface composite, a significant upconversion luminescence enhancement can be achieved with a maximum enhancement factor of 32.63 at 878 nm and an overall enhancement factor of 11.61. The luminescence dissymmetry factor of the induced upconverted circularly polarized luminescence can reach 0.95 at the emission wavelength of 895 nm. The UCNPs-on-metasurface composite yields efficient modulation for the emission intensity and polarization of UCNPs, paving new pathways to many potential applications in imaging, sensing, and anticounterfeiting fields.

11.
Opt Express ; 30(18): 31913-31924, 2022 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-36242264

RESUMEN

Actively tunable or reconfigurable structural colors are highly promising in future development for high resolution imaging and displaying applications. To this end, we demonstrate switchable structural colors covering the entire visible range by integrating aluminum nanoaperture arrays with nematic liquid crystals. The geometrically anisotropic design of the nanoapertures provides strong polarization-dependent coloration. By overlaying a nematic liquid crystal layer, we further demonstrate switchable ability of the structural colors by either changing the polarization of the incident light or applying an external voltage. The switchable structural colors have a fast response time of 28 ms at a driving voltage of 6.5 V. Furthermore, colorful patterns are demonstrated by coding the colors with various dimensions of nanoaperture arrays with dual switching modes. Our proposed technique in this work provides a dual-mode switchable structural colors, which is highly promising for polarimetric displays, imaging sensors, and visual cryptography.

12.
Adv Mater ; 34(37): e2203956, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35905504

RESUMEN

Chiral metasurfaces can exhibit a strong circular dichroism, but it is limited by the complicated fabrication procedure and alignment errors. Here, a new type of self-aligned suspended chiral bilayer metasurface with only one-step electron beam lithography exposure is demonstrated. A significant optical chirality of 221° µm-1 can be realized using suspended metasurfaces with a thickness of 100 nm. Furthermore, this study experimentally demonstrates that such a structure is capable of label-free discrimination of the chiral molecules at zeptomole level, exhibiting a much higher sensitivity (orders of magnitude) compared to the conventional circular dichroism spectroscopy. The fundamental principles for chiral sensing using molecules-metasurfaces interactions are explored. Benefiting from the giant chiroptical response, the proposed metadevice may offer promising applications for ultrathin circular polarizers, chiral molecular detectors, and asymmetry information processing.

13.
J Healthc Eng ; 2022: 5499354, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35035845

RESUMEN

In this paper, shear wave elastography was used to study and analyze the images of the breast in-depth and identify the abnormal image data. Sixty breast lesions were evaluated, and quantitative metrics were reproducible in the static and dynamic modes of shear wave elastography with a higher interobserver agreement in dynamic qualitative metrics than in the static mode. There were no statistically significant differences between the two modes of imaging in quantitative metrics, and quantitative metrics were more effective than qualitative metrics. Postoperative immunohistochemical expression of ER, PR, HER-2, Ki-67, molecular typing, pathological type, histological grading, and axillary lymph node status of breast cancer was obtained based on pathological results. The correlation between mass size, patient age, and WiMAX values of breast cancer masses was analyzed using Pearson correlation, and the differences in SWVmax values of breast cancer masses between different expressions of immunohistochemical parameters ER, PR, HER-2, Ki-67, and axillary lymph node status were compared using tests. The variables with correlations and differences were included in the multiple linear regression analysis to assess the factors influencing the SWVmax values. The performance of TDPM, SPM, and TSPM was compared using PVA body models with different freeze-thaw cycles. The results showed that TSPM performed better than SPM in general, and TDPM showed excellent performance because of high temporal resolution and low random error, especially when the number of freeze-thaw cycles increased and the hardness of the PVA body mold increased. Measurements at different depths of inhomogeneous body models also showed that the TDPM method was less affected by depth, and the results were more stable. Finally, the reliability of the shear wave velocity (SWS) measured by the TDPM and SPM methods was investigated using porcine ligament tissue, and the results showed that the mean values of SWS goodness of fit for TDPM and SPM were 0.94 and 0.87, respectively, and the estimated elastic modulus of TDPM was very close to the mechanical test results.


Asunto(s)
Neoplasias de la Mama , Diagnóstico por Imagen de Elasticidad , Animales , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/patología , Diagnóstico por Imagen de Elasticidad/métodos , Femenino , Humanos , Antígeno Ki-67 , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Porcinos
14.
Nano Lett ; 21(17): 7183-7190, 2021 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-34410715

RESUMEN

Metasurface-based structural coloration is a promising enabling technology for advanced optical encryption with a high-security level. Herein, we propose a paradigm of electrically switchable, polarization-sensitive optical encryption based on designed metasurfaces integrated with polymer-dispersed liquid crystals. The metasurfaces consist of anisotropic and isotropic aluminum nanoaperture arrays. Optical images can be encrypted by elaborately arranging anisotropic and isotropic nanoapertures based on their polarization-dependent plasmonic resonance characteristics. We demonstrate high-quality encrypted images and QR codes with electrically switchable, polarization-sensitive properties based on PDLC-integrated aluminum nanoaperture arrays. The proposed technique can be applied to many fields including high-security optical encryption, security tags, anticounterfeiting, multichannel imaging, and dynamic displays.

15.
Metab Syndr Relat Disord ; 18(8): 362-367, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32609042

RESUMEN

Background: Obstructive sleep apnea (OSA) is a serious threat to individual health. Diagnosis of OSA is mainly polysomnography (PSG). However, PSG monitoring is costly and time-consuming. At present, increasing studies are exploring new diagnostic methods for OSA. This study aimed to explore the diagnostic role of Sestrin2 in OSA. Materials and Methods: Sixty-four subjects were recruited in this study. The concentration of plasma Sestrin2 of all subjects were measured and compared. Spearman's correlation analysis was used to investigate the correlation between plasma Sestrin2 concentration and other factors. Receiver-operating characteristic (ROC) curve was used to investigate the role of Sestrin2 in the diagnosis of OSA, moderate-severe and severe OSA. Results: Subjects were divided into OSA group (n = 38) and control (n = 26). Levels of Plasma Sestrin2 were significantly higher in OSA patients than in controls. Sestrin2 was positively correlated with oxygen reduction index and negatively correlated with mean oxygen saturation and lowest oxygen saturation. The area under ROC curve (AUC) of Sestrin2 for OSA diagnosis was 0.740 [95% confidence interval (CI), 0.615-0.842], the cutoff value was 1.86 ng/mL, and the sensitivity and specificity were 81.58% and 61.54%, respectively. The AUC of Sestrin2 for the diagnosis of severe OSA was 0.801 (95% CI, 0.682-0.890), and the cutoff value was 5.21 ng/mL exhibiting the sensitivity and specificity of 61.90% and 90.70%, respectively. Conclusion: Setrin2 is a marker for OSA and may be helpful in the diagnosis of OSA.


Asunto(s)
Biomarcadores/sangre , Proteínas Nucleares/sangre , Apnea Obstructiva del Sueño/sangre , Adolescente , Adulto , Anciano , Área Bajo la Curva , Femenino , Humanos , Inflamación , Masculino , Persona de Mediana Edad , Estrés Oxidativo , Polisomnografía , Curva ROC , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Encuestas y Cuestionarios , Adulto Joven
16.
Nano Lett ; 20(6): 4204-4210, 2020 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-32412767

RESUMEN

Lanthanide-doped particles exhibit unique polarization-dependent luminescence due to the anisotropic crystalline local symmetry surrounding the emitter. Precise control of the orientation of particles shows great significance for exploiting the luminescent polarization and their potential applications. Here, we demonstrated a facile polypropylene-aided shear-driven method to obtain large-scale orientationally ordered upconversion nanorods, showing a liquid-crystalline nematic phase. Upconversion nanorods with low aspect ratios were well-aligned with the crystalline c-axis along the shearing direction using monodispersed colloid nanorods as the nanoink. The order parameter of aligned upconversion nanorods can reach up to 0.95. The nematic upconversion nanorods demonstrated strong polarization-dependent luminescence with the high degrees of polarization of the 4F9/2 sublevels at 657 and 661 nm being 0.47 and 0.59, respectively. Taking advantage of these mesoscopic well-aligned upconversion nanorods, their peculiar polarized emissions are potentially useful for some interdisciplinary applications such as polarization-sensitive bioprobes and anticounterfeiting.

17.
Nanomaterials (Basel) ; 10(4)2020 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-32260572

RESUMEN

Recently, photochemical synthesis has attracted wide interest on in situ preparing the surface-enhanced Raman scattering (SERS) substrate with excellent performance, especially in a compact space and microfluidic channel. Herein, a facile, green and cost-effective approach to in situ photochemically synthesize silver nanoaggregates is demonstrated for SERS applications. By adjusting the photo-irradiation conditions, the morphologies and sizes of the silver nanoaggregates can be deliberately tailored. The synthesized silver nanoaggregates-based substrates exhibit a highly sensitive and reproducible SERS activity with a low detection limit of 10-8 M for 4-Aminothiophenol detection and relative standard deviation of 12.3%, paving an efficient and promising route for in situ SERS-based rapid detection in the environmental monitoring and food quality control.

18.
ACS Appl Mater Interfaces ; 12(1): 1292-1298, 2020 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-31820628

RESUMEN

Greatly enhanced upconversion luminescence was demonstrated by integrating the core-shell upconversion nanorods with the Ag nanogratings. Both the Ag nanogratings and upconversion nanorods were fabricated/synthesized in a facile, cost-effective, high-throughput way. Experimental results showed that the upconversion luminescence intensity of Er3+ in the core-shell upconversion nanorods can be well tuned and enhanced by changing the shell thickness and the period of the Ag nanograting. The underlying physical mechanism for the upconversion luminescence enhancement was attributed to the plasmonically enhanced near infrared broadband absorption of the periodic Ag nanograting and the localized surface plasmon resonance of Ag nanocrystals. The maximum enhanced factors of 523 nm, 544 nm (green emission), and 658 nm (red emission) of Er3+ ions excited at 980 nm are 3.8-, 5.5-, and 4.6-folds, respectively. Our fabrication approach and results suggest that such a simple integration is potentially useful for biosensing/imaging and anti-counterfeiting applications.

19.
Opt Express ; 27(11): 15391-15398, 2019 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-31163736

RESUMEN

Electrically switchable photonic crystals are demonstrated based on TiO2 inverse opals infiltrated with liquid crystals. Macroporous anatase TiO2 inverse opals are fabricated from polystyrene opal templates through a sandwich vacuum backfilled method and followed by calcination. Upon liquid crystal infiltration, the optical properties of the hybrid organic/inorganic structure are characterized by reflectance measurements of the Bragg peak, the position of which can be switched using an external electric field. The physical mechanism underlying this switchable behavior is the reorientation of the liquid crystal molecules inside the spherical voids by the applied electric field, resulting in a significant change of the refractive index contrast between the liquid crystal and the TiO2 inverse opal. With advantageous features of cost-effective fabrication, easy integration, and electric control, such TiO2 inverse opals infiltrated with liquid crystals could play an important role in future development of active photonic devices.

20.
Materials (Basel) ; 11(10)2018 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-30261657

RESUMEN

In the past half-century, surface plasmon resonance in noble metallic nanoparticles has been an important research subject. Recent advances in the synthesis, assembly, characterization, and theories of traditional and non-traditional metal nanostructures open a new pathway to the kaleidoscopic applications of plasmonics. However, accurate and precise models of plasmon resonance are still challenging, as its characteristics can be affected by multiple factors. We herein summarize the recent advances of plasmonic nanoparticles and their applications, particularly regarding the fundamentals and applications of surface plasmon resonance (SPR) in Au nanoparticles, plasmon-enhanced upconversion luminescence, and plasmonic chiral metasurfaces.

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