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1.
Arch Rheumatol ; 39(2): 265-273, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38933715

ABSTRACT

Objectives: The study aimed to investigate the diagnostic values of different musculoskeletal ultrasound (MSUS) signs, serum uric acid (SUA), and their combined detection for gouty arthritis (GA). Patients and methods: In this retrospective study, 70 patients (62 males, 8 females; mean age: 46.1±14.1 years; range, 25 to 86 years) diagnosed with GA (the GA group) between August 2022 and March 2023 and 70 patients (54 females, 16 males; mean age: 49.0±14.1 years; range, 21 to 75 years) diagnosed with rheumatoid arthritis and osteoarthritis during the same period (the non-GA group) were included. The positive rate of MSUS signs and SUA in both groups was recorded to compare the differences. The correlations of MSUS signs and SUA with GA were analyzed using Spearman's rank correlation analysis. The diagnostic values of different MSUS signs, SUA, and their combined detection for GA were analyzed using a receiver operating characteristic, the area under the curve (AUC), sensitivity, specificity, and the Youden index. Results: The positive rate of the double contour (DC) sign (chi-squared [χ2 ]=102.935, p<0.001), hyperechoic spots (χ2=56.395, p<0.001), bone erosions (χ2 =10.080, p<0.001), and SUA (χ2 =41.117, p <0.001) were higher in the GA group than in the non-GA group. The positive rate of the DC sign (rs=0.829, p=0.001), hyperechoic spots (rs=0.631, p<0.001), bone erosion (rs=0.268, p=0.001), and SUA (rs=0.542, p<0.001) were positively correlated with GA. Among the single-indicator measures, the DC sign exhibited the highest diagnostic value (AUC=0.907, sensitivity=81.4%, specificity=100%, p<0.001). Among the combined-indicator measures, the DC sign combined with SUA exhibited the highest diagnostic value (AUC=0.929, sensitivity=91.4%, specificity=94.3%, p<0.001), higher than DC sign detection alone. Conclusion: The DC sign combined with SUA yielded a high diagnostic value and can thus provide a reliable basis for effectively and efficiently diagnosing GA.

2.
Chem Sci ; 15(17): 6552-6561, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38699257

ABSTRACT

Mucin-related tumor-associated carbohydrate antigens (TACAs) are important and interesting targets for cancer vaccine therapy. However, efficient access to a library of mucin-related TACAs remains a challenging task. One of the key issues is the challenging construction of α-GalNAc linkages. Here, we report highly stereoselective α-glycosylation with GalN3N-phenyl trifluoroacetimidate donors, which features excellent yields, outstanding stereoselectivities, broad substrate scope and mild reaction conditions. This method is successfully applied to highly stereoselective synthesis of GalN3-α-O-Ser, which served as the common intermediate for collective synthesis of a wide range of TACAs including TN antigen, STN antigen, 2,6 STF antigen, 2,3 STF antigen, glycophorin and cores 1-8 mucin-type O-glycans. In particular, the rationale for this highly stereoselective α-glycosylation is provided for the first time using DFT calculations and mechanistic studies, highlighting the crucial roles of reagent combinations (TMSI and Ph3PO) and the H-bonding directing effect of the N3 group.

3.
Anal Bioanal Chem ; 416(18): 4143-4152, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38777877

ABSTRACT

Fluorescence dye-based loop-mediated isothermal amplification (LAMP) is a sensitive nucleic acid detection method, but is limited to single-plex detection and may yield non-specific signals. In this study, we propose a bifunctional probe-based real-time LAMP amplification method for single-plexed or multiplexed detection. The bifunctional probe is derived by modifying the 5' end of the fluorophore and an internal quencher on one of the LAMP primers; therefore, it can simultaneously be involved in the LAMP process and signal amplification. The fluorescence intensity undergoes a cumulative exponential increase during the incorporation of the bifunctional probe into double-stranded DNA amplicons. The bifunctional probe-based LAMP method is simplified and cost-effective, as the primer design and experimental operations align entirely with the ordinary LAMP. Different from other current probe-based methods, this method does not require additional enzymes, sequences, or special probe structures. Also, it is 10 min faster than several other probe-based LAMP methods. The bifunctional probe-based LAMP method allows the simultaneous detection of the target Vibrio parahaemolyticus DNA and the internal amplification control in a one-pot reaction, demonstrating its potential for multiplexed detection.


Subject(s)
Nucleic Acid Amplification Techniques , Vibrio parahaemolyticus , Nucleic Acid Amplification Techniques/methods , Vibrio parahaemolyticus/genetics , Vibrio parahaemolyticus/isolation & purification , DNA, Bacterial/analysis , DNA, Bacterial/genetics , Fluorescent Dyes/chemistry , Limit of Detection , DNA Primers , Molecular Diagnostic Techniques/methods
4.
Dent Mater ; 2024 May 30.
Article in English | MEDLINE | ID: mdl-38821839

ABSTRACT

OBJECTIVE: Extrafibrillar demineralization is considered to be an ideal solution for addressing the durability of resin-dentin bonding interfaces. However, its theoretical basis is contradictory to ionization equilibrium of hydroxyapatite dissolution. In this study, various calcium chelators were selected as dentin conditioners to explore the essence of dentin demineralization with chelators and its effect on resin-dentin adhesion. METHODS: Polyethyleneimine grafted with EDTA and polyacrylic acid sodium (PAAN450k) larger than 40 kDa, as well as PAAN (PAAN3k) and EDTA smaller than 6 kDa, were prepared as dentin conditioners. The dentin powder was designed to characterize whether it would demineralize without contact with PAAN450k. Dentin demineralization effect with four conditioners was evaluated with field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, atomic force microscopy and quantification of hydroxyproline concentration after enzymatic degradation. Micro-tensile bond strength (µTBS) test and failure mode analysis were employed to assess the bonding effect of the four chelators in both wet and dry bonding, with H3PO4 wet bonding serving as the control group. RESULTS: Demineralization occurs when PAAN450k was not in direct contact with the dentin powder. The extrafibrillar demineralization cannot be induced by any chelator regardless of its molecular weight. Complete demineralization including extrafibrillar and intrafibrillar demineralization would occur with sufficient interaction time. Moreover, chelators could not provide a reliable dentin bonding effect under a short interaction time. SIGNIFICANCE: From the perspective of theory and application, extrafibrillar demineralization is not a reliable strategy, which provides a reminder for exploring new strategies in the future.

5.
Nat Commun ; 15(1): 3257, 2024 Apr 16.
Article in English | MEDLINE | ID: mdl-38627413

ABSTRACT

Biological nervous system outperforms in both dynamic and static information perception due to their capability to integrate the sensing, memory and processing functions. Reconfigurable neuromorphic transistors, which can be used to emulate different types of biological analogues in a single device, are important for creating compact and efficient neuromorphic computing networks, but their design remains challenging due to the need for opposing physical mechanisms to achieve different functions. Here we report a neuromorphic electrolyte-gated transistor that can be reconfigured to perform physical reservoir and synaptic functions. The device exhibits dynamics with tunable time-scales under optical and electrical stimuli. The nonlinear volatile property is suitable for reservoir computing, which can be used for multimodal pre-processing. The nonvolatility and programmability of the device through ion insertion/extraction achieved via electrolyte gating, which are required to realize synaptic functions, are verified. The device's superior performance in mimicking human perception of dynamic and static multisensory information based on the reconfigurable neuromorphic functions is also demonstrated. The present study provides an exciting paradigm for the realization of multimodal reconfigurable devices and opens an avenue for mimicking biological multisensory fusion.

6.
Light Sci Appl ; 13(1): 67, 2024 Mar 05.
Article in English | MEDLINE | ID: mdl-38443377

ABSTRACT

High-performance active terahertz modulators as the indispensable core components are of great importance for the next generation communication technology. However, they currently suffer from the tradeoff between modulation depth and speed. Here, we introduce two-dimensional (2D) tellurium (Te) nanofilms with the unique structure as a new class of optically controlled terahertz modulators and demonstrate their integrated heterojunctions can successfully improve the device performances to the optimal and applicable levels among the existing all-2D broadband modulators. Further photoresponse measurements confirm the significant impact of the stacking order. We first clarify the direction of the substrate-induced electric field through first-principles calculations and uncover the unusual interaction mechanism in the photoexcited carrier dynamics associated with the charge transfer and interlayer exciton recombination. This advances the fundamental and applicative research of Te nanomaterials in high-performance terahertz optoelectronics.

7.
Nanomaterials (Basel) ; 13(21)2023 Oct 27.
Article in English | MEDLINE | ID: mdl-37947692

ABSTRACT

We numerically and experimentally demonstrate a terahertz metadevice consisting of split-ring resonators (SRRs) present within square metallic rings. This device can function as a dual-band polarization converter by breaking the symmetry of SRRs. Under x-polarized incidence, the metastructure is able to convert linearly polarized (LP) light into a left-hand circular-polarized (LCP) wave. Intriguingly, under y-polarized incidence, frequency-dependent conversion from LP to LCP and right-hand circular-polarized (RCP) states can be achieved at different frequencies. Furthermore, reconfigurable LCP-to-LP and RCP-to-LP switching can be simulated by integrating the device with patterned graphene and changing its Fermi energy. This dual-band and multi-state polarization control provides an alternative solution to developing compact and multifunctional components in the terahertz regime.

8.
Anal Chim Acta ; 1280: 341860, 2023 Nov 01.
Article in English | MEDLINE | ID: mdl-37858552

ABSTRACT

BACKGROUND: A false negative result is one of the major problems in nucleic acid detection. Failure to screen positive samples for pathogens or viruses poses a risk to public health. This situation will lead to more serious consequences for infectious pathogens or viruses. At present, the common solution is to introduce exogenous or endogenous internal control. Because it amplifies and is detected separately from the target gene, it cannot avoid false negative results caused by DNA extraction failure or reagent inactivation. There is an urgent need for a simple and reliable method to solve the false negative problem of nucleic acid detection. RESULTS: We established a chip and an on-chip detection method for the integrated detection of target genes and internal control using the CRISPR system in LAMP amplification products. The chip is processed from a low-cost PMMA board and has three chambers and some channels. After adding the sample, the chip only needs to be rotated twice, and the sample enters three chambers successively depending on its gravity for dual LAMP reaction and CRISPR detections. With a portable LED blue light exciter, visual fluorescence detection is realized. Whether the detection result is positive, negative, or invalid can be determined according to the fluorescence in the CRISPR chamber for target gene and CRISPR chamber for internal control. In this study, the detection of Salmonella enterica in Fenneropenaeus chinensis was taken as an example. The results showed good specificity and sensitivity. It could detect as low as 15 copies/µL of Salmonella enterica. SIGNIFICANCE: The on-chip detection solves the problem of aerosol contamination and false negative results. It has the advantages of high sensitivity, high specificity, high accuracy, and low cost. This research will advance the development of nucleic acid detection technology, providing a new and reliable strategy for POCT detection of pathogenic bacteria and viruses.


Subject(s)
CRISPR-Cas Systems , Nucleic Acids , Fluorescence , Drug Contamination , Light , Nucleic Acid Amplification Techniques
9.
Front Cardiovasc Med ; 10: 1224795, 2023.
Article in English | MEDLINE | ID: mdl-37736023

ABSTRACT

Background: Hypertension is a major public health problem, and its resulting other cardiovascular diseases are the leading cause of death worldwide. In this study, we constructed a convenient and high-performance hypertension risk prediction model to assist in clinical diagnosis and explore other important influencing factors. Methods: We included 8,073 people from NHANES (2017-March 2020), using their 120 features to form the original dataset. After data pre-processing, we removed several redundant features through LASSO regression and correlation analysis. Thirteen commonly used machine learning methods were used to construct prediction models, and then, the methods with better performance were coupled with recursive feature elimination to determine the optimal feature subset. After data balancing through SMOTE, we integrated these better-performing learners to construct a fusion model based for predicting hypertension risk on stacking strategy. In addition, to explore the relationship between serum ferritin and the risk of hypertension, we performed a univariate analysis and divided it into four level groups (Q1 to Q4) by quartiles, with the lowest level group (Q1) as the reference, and performed multiple logistic regression analysis and trend analysis. Results: The optimal feature subsets were: age, BMI, waist, SBP, DBP, Cre, UACR, serum ferritin, HbA1C, and doctors recommend reducing salt intake. Compared to other machine learning models, the constructed fusion model showed better predictive performance with precision, accuracy, recall, F1 value and AUC of 0.871, 0.873, 0.871, 0.869 and 0.966, respectively. For the analysis of the relationship between serum ferritin and hypertension, after controlling for all co-variates, OR and 95% CI from Q2 to Q4, compared to Q1, were 1.396 (1.176-1.658), 1.499 (1.254-1.791), and 1.645 (1.360-1.989), respectively, with P < 0.01 and P for trend <0.001. Conclusion: The hypertension risk prediction model developed in this study is efficient in predicting hypertension with only 10 low-cost and easily accessible features, which is cost-effective in assisting clinical diagnosis. We also found a trend correlation between serum ferritin levels and the risk of hypertension.

10.
ACS Appl Mater Interfaces ; 15(33): 39127-39142, 2023 Aug 23.
Article in English | MEDLINE | ID: mdl-37565782

ABSTRACT

Dentin bond interface stability is the key issue of dental adhesion in present clinical dentistry. The concept of selective extrafibrillar demineralization has opened a new way to maintain intrafibrillar minerals to prevent interface degradation. Here, using ultra-high-molecular-weight sodium polyacrylate [Carbopol (Carbo) > 40 kDa] as a calcium chelator, we challenge this concept and propose a protocol for reliable dentin dry bonding. The results of high-resolution transmission electron microscopy revealed periodic bands of 67 nm dentin collagen fibrils after Carbo etching, and the hydroxyproline concentration increasing with prolonged chelating time denied the concept of extrafibrillar demineralization. The results that wet and dry bonding with Carbo-based demineralization produced a weaker bond strength than the traditional phosphoric acid wet adhesion suggested that the Carbo-based demineralization is an unreliable adhesion strategy. A novel protocol of Er:YAG laser physical etching followed by Carbo chemical etching for dentin adhesion revealed that a micro-/nano-level rough, rigid, and non-collagen exposed dentin surface was produced, the micro-tensile bond strength was maintained after aging under dry and wet bonding modes, and in situ zymography and nanoleakage within the hybrid layers presented lower signals after aging. Cell culture in vitro and a rabbit deep dentin adhesion model in vivo proved that this protocol is safe and biocompatible. Taken together, the concept of extrafibrillar demineralization is limited and insufficient to use in the clinic. The strategy of Er:YAG laser physical etching followed by Carbo chemical etching for dentin adhesion produces a bonding effect with reliability, durability, and safety.


Subject(s)
Lasers, Solid-State , Rabbits , Animals , Reproducibility of Results , Dentin , Dentin-Bonding Agents/chemistry , Tensile Strength , Microscopy, Electron, Scanning , Materials Testing , Surface Properties
11.
Zhongguo Yi Liao Qi Xie Za Zhi ; 47(3): 341-345, 2023 May 30.
Article in Chinese | MEDLINE | ID: mdl-37288642

ABSTRACT

Aiming at the management efficiency problems in the traditional medical low-value consumables management mode of the nursing unit, based on the perspective of supply chain management, this study uses lean management method to construct the lean management mode of low-value consumables with a whole cycle and whole process information monitoring, and analyzes the application effect of this mode. The results show that after the application of lean management mode, the low-value consumables of the nursing unit can achieve "consumables in use=priced consumables + un-priced consumables", the settlement cost is significantly reduced and its stability is high, and the efficiency of "supply-inventor-distribution" link is significantly enhanced. This model effectively improves the management efficiency of low-value consumables in the hospital, and also provides a reference for other hospitals to improve the management level of low-value consumables.


Subject(s)
Commerce , Hospitals
12.
Biosens Bioelectron ; 230: 115282, 2023 Jun 15.
Article in English | MEDLINE | ID: mdl-37028002

ABSTRACT

In addition to carrying and transmitting genetic material, some DNA molecules have specific binding ability or catalytic function. DNA with this special function is collectively referred to as functional DNA (fDNA), such as aptamer, DNAzyme and so on. fDNA has the advantages of simple synthetic process, low cost and low toxicity. It also has high chemical stability, recognition specificity and biocompatibility. In recent years, fDNA biosensors have been widely investigated as signal recognition elements and signal transduction elements for the detection of non-nucleic acid targets. However, the main problem of fDNA sensors is their limited sensitivity to trace targets, especially when the affinity of fDNA to the targets is low. To further improve the sensitivity, various nucleic acid signal amplification strategies (NASAS) are explored to improve the limit of detection of fDNA. In this review, we will introduce four NASAS (hybridization chain reaction, entropy-driven catalysis, rolling circle amplification, CRISPR/Cas system) and the corresponding design principles. The principle and application of these fDNA sensors integrated with signal amplification strategies for detection of non-nucleic acid targets are summarized. Finally, the main challenges and application prospects of NASAS integrated fDNA biosensing system are discussed.


Subject(s)
Biosensing Techniques , DNA, Catalytic , DNA/chemistry , DNA, Catalytic/chemistry , Nucleic Acid Hybridization , Oligonucleotides , Nucleic Acid Amplification Techniques
13.
Angew Chem Int Ed Engl ; 62(22): e202301351, 2023 05 22.
Article in English | MEDLINE | ID: mdl-36867119

ABSTRACT

Lipopolysaccharides from Bacteroides vulgatus represent interesting targets for the treatment of inflammatory bowel diseases. However, efficient access to long, branched and complex lipopolysaccharides remains challenging. Herein, we report the modular synthesis of a tridecasaccharide from Bacteroides vulgates through an orthogonal one-pot glycosylation strategy based on glycosyl ortho-(1-phenylvinyl)benzoates, which avoids the issues of thioglycoside-based one-pot synthesis. Our approach also features: 1) 5,7-O-di-tert-butylsilylene-directed glycosylation for stereoselective construction of the α-Kdo linkage; 2) hydrogen-bond-mediated aglycone delivery for the stereoselective formation of ß-mannosidic bonds; 3) remote anchimeric assistance for stereoselective assembly of the α-fucosyl linkage; 4) several orthogonal one-pot synthetic steps and strategic use of orthogonal protecting groups to streamline oligosaccharide assembly; 5) convergent [1+6+6] one-pot synthesis of the target.


Subject(s)
Inflammatory Bowel Diseases , Lipopolysaccharides , Humans , Lipopolysaccharides/chemistry , Glycosylation , Oligosaccharides/chemistry , Bacteroides
14.
Zhongguo Yi Liao Qi Xie Za Zhi ; 46(2): 230-232, 2022 Mar 30.
Article in Chinese | MEDLINE | ID: mdl-35411757

ABSTRACT

The management of in vitro diagnostic reagents has always been a concern. This paper describes the application of SPD medical consumables fine management system in our hospital. Relying on the brand-new management mode, the whole process from supplier qualification certificate management, in vitro diagnostic reagent procurement management, secondary warehouse management, and then to the use process traceability was realized. The monthly cost of in vitro diagnostic reagents can be accurately counted, which effectively controls the cost of in vitro diagnostic reagents.


Subject(s)
Hospitals , Indicators and Reagents
15.
Nat Commun ; 13(1): 1729, 2022 04 01.
Article in English | MEDLINE | ID: mdl-35365642

ABSTRACT

In the quest for emerging in-sensor computing, materials that respond to optical stimuli in conjunction with non-volatile phase transition are highly desired for realizing bioinspired neuromorphic vision components. Here, we report a non-volatile multi-level control of VO2 films by oxygen stoichiometry engineering under ultraviolet irradiation. Based on the reversible regulation of VO2 films using ultraviolet irradiation and electrolyte gating, we demonstrate a proof-of-principle neuromorphic ultraviolet sensor with integrated sensing, memory, and processing functions at room temperature, and also prove its silicon compatible potential through the wafer-scale integration of a neuromorphic sensor array. The device displays linear weight update with optical writing because its metallic phase proportion increases almost linearly with the light dosage. Moreover, the artificial neural network consisting of this neuromorphic sensor can extract ultraviolet information from the surrounding environment, and significantly improve the recognition accuracy from 24% to 93%. This work provides a path to design neuromorphic sensors and will facilitate the potential applications in artificial vision systems.


Subject(s)
Neural Networks, Computer , Vision, Ocular , Phase Transition
16.
Nano Lett ; 22(4): 1541-1548, 2022 Feb 23.
Article in English | MEDLINE | ID: mdl-35118860

ABSTRACT

Optical regulation strategy with the aid of hybrid materials can significantly optimize the performance of terahertz devices. Gold nanobipyramids (AuNBPs) with synthetical tunability to the near-infrared band show strong local field enhancement, which improves optical coupling at the interface and benefits the modulation performance. We design AuNBPs-integrated terahertz modulators with multiple structured surfaces and demonstrate that introducing AuNBPs can effectively enhance their modulation depths. In particular, an ultrahigh modulation enhancement of 1 order of magnitude can be achieved in the AuNBPs hybrid metamaterials accompanied by the multifunctional modulation characteristics. By application of the coupled Lorentz oscillator model, the theoretical calculation suggests that the optical regulation with AuNBPs originates from increased damping rate and higher coupling coefficient under pump excitation. Additionally, a terahertz spatial light modulator is constructed to demonstrate multiple imaging display and consume extremely low power, which is promising for the potential application in spatial and frequency selective imaging.

17.
Spectrochim Acta A Mol Biomol Spectrosc ; 270: 120812, 2022 Apr 05.
Article in English | MEDLINE | ID: mdl-34999362

ABSTRACT

Glycerol is an important quality indicator for foodstuffs. There is an increasing request for one more accurate, reliable, and convenient detection of the glycerol concentrations. Terahertz radiation is highly sensitive to the low-frequency intermolecular interactions between the glycerol and waters. Considering the enhancement property of localized field from the metamaterials, terahertz spectroscopy has been utilized for the determination of glycerol content with metamaterial-based biosensor, where the interaction between the analyte and the terahertz wave can be greatly increased. But the quantitative sensing performance was poor due to the sensitivity limitation of single-mode resonance of metamaterial and the lack of appropriate modeling methods. We propose the optimized structural design with internal coupling and multiple resonances. The induced remarkable changes in the lineshape of different transmitted dip regions imply that our metastructure biosensor is of high sensitivity to the change of surrounding environment on the surface dielectric constant, which has been also verified by coupled Lorentz oscillator theory. Furthermore, the optimal partial least squares regression model with variables of spectral lineshape for the first dip region covering the frequency range of 0.45-0.85 THz was established. It shows more accurate and reliable predictions of glycerol concentrations with residual predictive deviation value of 6.095. Metamaterial-based terahertz spectroscopy combined with statistical modeling with lineshape features can provide one new strategy for quantitative sensing. It has great potential for the improvement of determination of analyte concentrations in the practical applications of food, pharmaceutical or cosmetic area.


Subject(s)
Biosensing Techniques , Terahertz Spectroscopy , Glycerol , Least-Squares Analysis , Water
18.
Int J Biol Macromol ; 183: 2131-2141, 2021 Jul 31.
Article in English | MEDLINE | ID: mdl-34111481

ABSTRACT

Enamel regeneration currently -is limited by our inability to duplicate artificially its complicated and well-aligned hydroxyapatite structure. The initial formation of enamel occurs in enamel organs where the ameloblasts secret enamel extracellular matrix formed a unique gel-like microenvironment. The enamel extracellular matrix is mainly composed by amelogenin and non-amelogenin. In this study, an innovative strategy was proposed to regenerate enamel-like tissue by constructing a microenvironment using biomimetic enamel matrix proteins (biomimetic EMPs) composed of modified leucine-rich amelogenin peptide (mLRAP) and non-amelogenin analog (NAA). Impressively, the regenerated enamel in this biomimetic EMPs on etched enamel surface produced prismatic structures, and showed similar mechanical properties to natural enamel. The results of X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) showed that regenerated crystal was hydroxyapatite. Molecular dynamics simulation analysis showed the binding energy between mLRAP and NAA were electrostatic forces and Van der Walls. These results introduced a promising strategy to induce crystal growth of enamel-like hydroxyapatite for biomimetic reproduction of materials with complicated hierarchical microstructures.


Subject(s)
Amelogenesis , Biomimetic Materials/chemistry , Biomimetic Materials/metabolism , Dental Enamel Proteins/metabolism , Dental Enamel/metabolism , Mesenchymal Stem Cells/metabolism , Regeneration , Tissue Engineering , Cell Proliferation , Cells, Cultured , Crystallization , Dental Enamel/chemistry , Dental Enamel/ultrastructure , Dental Enamel Proteins/chemistry , Dental Enamel Proteins/ultrastructure , Molecular Docking Simulation , Molecular Dynamics Simulation , Protein Conformation , Structure-Activity Relationship
19.
ACS Appl Mater Interfaces ; 13(11): 13565-13575, 2021 Mar 24.
Article in English | MEDLINE | ID: mdl-33720680

ABSTRACT

We have demonstrated the active manipulation of metamaterial-induced transparency (MIT) in a terahertz hybrid metamaterial with graphene overlayer under photoexcitation. It is found that the introduction of graphene can greatly modify the resonant dips and transparency window through the formed depolarization field around unequal-length double bars to weaken dipole resonances and their destructive interference. Transient control of MIT behaviors is determined by the photogenerated carrier dynamics, which influences the distributions of currents and electric fields in the resonant region to hinder the near-field coupling of two bright modes. Optical modulation depth is sensitive to bar spacing due to an anomalous increased double-bar coupling involving intracell and intercell interaction. Heterointerface formed by the added graphene with substrate could further enhance terahertz response via effective separation of the photoexcited carriers. Theoretical calculation based on the coupled Lorentz oscillator model reveals that the photoinduced terahertz response mainly originates from the coupling and damping in hybrid structures. Our findings could facilitate the development of graphene-based dynamical terahertz modulators and optoelectronic devices.

20.
Opt Express ; 28(21): 31436-31445, 2020 Oct 12.
Article in English | MEDLINE | ID: mdl-33115116

ABSTRACT

We have grown VO2 films and combined with terahertz metamaterials to manipulate the memory effect during the insulator-to-metal transition. The temperature-dependent resonant frequency of hybrid structure shows a thermal hysteresis accompanied with frequency shift and bandwidth variation due to the presence of a VO2 dielectric layer. This frequency memory effect significantly depends on the metallic micro-structure. Further theoretical calculation demonstrates this phenomenon mainly originates from the different coupling strength between VO2 and metallic structures. Our findings could facilitate the application of VO2 films in the smart window and dynamical terahertz modulators.

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