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1.
Chin Herb Med ; 16(3): 327-343, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-39072195

RESUMEN

Platycodonis Radix (Jiegeng in Chinese) is a well-known traditional Chinese medicine used for both medicinal and culinary purposes. Its historical use as an antitussive and expectorant has been extensively documented. Researchers, to date, have identified 219 chemical constituents in Platycodon grandiflorum (Jacq.) A. DC, encompassing 89 saponins, 11 flavonoids, 21 polysaccharides, 14 phenolic acids, six polyacetylenes, five sterols, 34 fatty acids, 17 amino acids, and 22 trace elements. Jiegeng exhibits diverse pharmacological effects, including antitussive and anti-phlegm properties, anti-cancer activity, anti-inflammatory effects, immune regulation, antioxidant properties, anti-obesity, and antidiabetic effects. Additionally, Jiegeng shows potential in protecting the heart and liver. Beyond its medicinal benefits, Jiegeng is highly esteemed in culinary applications, and its global demand is on the rise. Its utilization has expanded beyond medicine and food to encompass daily necessities, cosmetics, agricultural supplies, and other fields. Currently, there are 18 272 patents related to P. grandiflorum. This comprehensive review summarizes the latest research published over the past 20 years, providing a robust foundation for further exploration of the medicinal and health benefits of P. grandiflorum.

2.
Bioinformatics ; 40(7)2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38954836

RESUMEN

MOTIVATION: Accurately detecting pathogenic microorganisms requires effective primers and probe designs. Literature-derived primers are a valuable resource as they have been tested and proven effective in previous research. However, manually mining primers from published texts is time-consuming and limited in species scop. RESULTS: To address these challenges, we have developed MiPRIME, a real-time Microbial Primer Mining platform for primer/probe sequences extraction of pathogenic microorganisms with three highlights: (i) comprehensive integration. Covering >40 million articles and 548 942 organisms, the platform enables high-frequency microbial gene discovery from a global perspective, facilitating user-defined primer design and advancing microbial research. (ii) Using a BioBERT-based text mining model with 98.02% accuracy, greatly reducing information processing time. (iii) Using a primer ranking score, PRscore, for intelligent recommendation of species-specific primers. Overall, MiPRIME is a practical tool for primer mining in the pan-microbial field, saving time and cost of trial-and-error experiments. AVAILABILITY AND IMPLEMENTATION: The web is available at {{https://www.ai-bt.com}}.


Asunto(s)
Cartilla de ADN , Minería de Datos , Minería de Datos/métodos , Programas Informáticos , Bacterias/genética , Bacterias/clasificación
3.
Sci Rep ; 14(1): 13516, 2024 06 12.
Artículo en Inglés | MEDLINE | ID: mdl-38866797

RESUMEN

Diarrhea and constipation are common health concerns in children. Numerous studies have identified strong association between gut microbiota and digestive-related diseases. But little is known about the gut microbiota that simultaneously affects both diarrhea and constipation or their potential regulatory mechanisms. Stool samples from 618 children (66 diarrhea, 138 constipation, 414 healthy controls) aged 0-3 years were collected to investigate gut microbiota changes using 16S rRNA sequencing. Compared with healthy, children with diarrhea exhibited a significant decrease in microbial diversity, while those with constipation showed a marked increase (p < 0.05). Significantly, our results firstly Ruminococcus increased in constipation (p = 0.03) and decreased in diarrhea (p < 0.01) compared to healthy controls. Pathway analysis revealed that Ruminococcus highly involved in the regulation of five common pathways (membrane transport, nervous system, energy metabolism, signal transduction and endocrine system pathways) between diarrhea and constipation, suggesting a potential shared regulatory mechanism. Our finding firstly reveals one core microorganisms that may affect the steady balance of the gut in children with diarrhea or constipation, providing an important reference for potential diagnosis and treatment of constipation and diarrhea.


Asunto(s)
Estreñimiento , Diarrea , Microbioma Gastrointestinal , ARN Ribosómico 16S , Humanos , Estreñimiento/microbiología , Diarrea/microbiología , Preescolar , Lactante , Masculino , Femenino , ARN Ribosómico 16S/genética , Heces/microbiología , Recién Nacido , China , Estudios de Casos y Controles , Pueblos del Este de Asia
4.
BMC Cancer ; 24(1): 601, 2024 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-38760826

RESUMEN

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a significant global health issue, suspected to elevate the risk for various cancers. This study sought to discern whether COPD serves as a risk marker or a causative factor for prevalent cancers. METHODS: We employed univariable MR (UVMR) analyses to investigate the causal relationship between COPD and the top ten common cancers. Sensitivity analyses were performed to validate the main findings. Multivariable MR (MVMR) and two-step MR analyses were also conducted. False-discovery-rate (FDR) was used to correct multiple testing bias. RESULTS: The UVMR analysis demonstrated notable associations between COPD and lung cancer (odds ratio [OR] = 1.42, 95%CI 1.15-1.77, FDR = 6.37 × 10-3). This relationship extends to lung cancer subtypes such as squamous cell carcinoma (LUSC), adenocarcinoma (LUAD), and small cell lung cancer (SCLC). A tentative link was also identified between COPD and bladder cancer (OR = 1.53, 95%CI 1.03-2.28, FDR = 0.125). No significant associations were found between COPD and other types of cancer. The MVMR analysis that adjusted for smoking, alcohol drinking, and body mass index did not identify any significant causal relationships between COPD and either lung or bladder cancer. However, the two-step MR analysis indicates that COPD mediated 19.2% (95% CI 12.7-26.1%), 36.1% (24.9-33.2%), 35.9% (25.7-34.9%), and 35.5% (26.2-34.8%) of the association between smoking and overall lung cancer, as well as LUAD, LUSC, and SCLC, respectively. CONCLUSIONS: COPD appears to act more as a risk marker than a direct cause of prevalent cancers. Importantly, it partially mediates the connection between smoking and lung cancer, underscoring its role in lung cancer prevention strategies.


Asunto(s)
Neoplasias Pulmonares , Análisis de la Aleatorización Mendeliana , Enfermedad Pulmonar Obstructiva Crónica , Humanos , Enfermedad Pulmonar Obstructiva Crónica/epidemiología , Enfermedad Pulmonar Obstructiva Crónica/genética , Neoplasias Pulmonares/epidemiología , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/etiología , Factores de Riesgo , Neoplasias/epidemiología , Neoplasias/genética , Fumar/efectos adversos , Fumar/epidemiología , Masculino , Oportunidad Relativa
5.
Adv Mater ; 36(27): e2401869, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38641342

RESUMEN

Smart windows with radiative heat management capability using the sun and outer space as zero-energy thermodynamic resources have gained prominence, demonstrating a minimum carbon footprint. However, realizing on-demand thermal management throughout all seasons while reducing fossil energy consumption remains a formidable challenge. Herein, an energy-efficient smart window that enables actively tunable passive radiative cooling (PRC) and multimode heating regulation is demonstrated by integrating the emission-enhanced polymer-dispersed liquid crystal (SiO2@PRC PDLC) film and a low-emission layer deposited with carbon nanotubes. Specifically, this device can achieve a temperature close to the chamber interior ambient under solar irradiance of 700 W m-2, as well as a temperature drop of 2.3 °C at sunlight of 500 W m-2, whose multistage PRC efficiency can be rapidly adjusted by a moderate voltage. Meanwhile, synchronous cooperation of passive radiative heating (PRH), solar heating (SH), and electric heating (EH) endows this smart window with the capability to handle complicated heating situations during cold weather. Energy simulation reveals the substantial superiority of this device in energy savings compared with single-layer SiO2@PRC PDLC, normal glass, and commercial low-E glass when applied in different climate zones. This work provides a feasible pathway for year-round thermal management, presenting a huge potential in energy-saving applications.

6.
Adv Mater ; 36(8): e2305872, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38016803

RESUMEN

The development of an integrated material system capable of effectively organizing and combining multisource information, such as dynamic pigmentary, structural, and fluorescent colors, is significant and challenging. Achieving such programmable dynamic information storage can considerably enhance the diversity and security of information deliveries. Here, a polymer-stabilized cholesteric liquid crystal system with highly temperature-sensitive structural color and light-sensitive pigmentary and fluorescence colors is presented. The prepared cholesteric liquid crystals (clcs) can reversibly change their structural color from red to blue within variational 3 °C near room temperature, and exhibit a gradually adjustable fluorescence which can transform from blue to pink and finally to bright red. All this dynamic information is programmable and tailored, hundreds of thousands of (>540 000) pattern combinations can easily be achieved by optical writing with a "bagua" pattern photomask. Therefore, if the corresponding code combinations to the pattern are assigned particular meanings, encrypted transmission of information with very high security can be achieved by utilizing applicable information encoding tables and decryption rules.

7.
Sci Rep ; 13(1): 14425, 2023 09 02.
Artículo en Inglés | MEDLINE | ID: mdl-37660184

RESUMEN

High-throughput sequencing allows for the comprehensive analysis of the human intestinal microbiota. However, extensive association analyses between the microbiome and lifestyle differences in the Chinese population are limited. Here, we carried out an independent cohort study-the Chinese Healthy Gut Project (n = 483)-where correlations between the gut microbiota and dietary and lifestyle variables in a healthy Chinese population are defined. We collected both questionnaire data, including basic information and lifestyle and dietary variables, and fecal stools from the enrolled volunteers. We then performed 16S rRNA sequencing on the microbial DNA isolated from the stools to assess the composition of the intestinal microbiota. We found that Prevotella and Bacteroides were the most abundant genera in the healthy Chinese gut microbiome. Additionally, 9 out of 29 clinical and questionnaire-based phenotype covariates were found to be associated with the variation in the composition of the gut microbiota. Among these lifestyle phenotypes, sleep procrastination, negative mood, and drinking habits had the largest effect size. Additionally, an appreciable effect of urbanization was observed, resulting in decreased intra-individual diversity, increased inter-individual diversity, and an increased abundance of the Bacteroides enterotype. The results of this study provide a foundation for assessing the healthy Chinese gut microbiota community structure at baseline in a healthy Chinese population. Furthermore, this study also provides insights into understanding how distinctive living habits influence the relationships between the Chinese gut microbiome and systemic health state.


Asunto(s)
Microbioma Gastrointestinal , Estilo de Vida , Humanos , Bacteroides/genética , Estudios de Cohortes , Pueblos del Este de Asia , Microbioma Gastrointestinal/genética , ARN Ribosómico 16S/genética , Voluntarios Sanos , Heces/microbiología
8.
Adv Mater ; 35(41): e2302168, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37459653

RESUMEN

In recent years, light-driven soft actuators have been rapidly developed as enablers in the fabrication of artificial robots and biomimetic devices. However, it remains challenging to amplify molecular isomerization to multiple modes of macroscopic actuation with large amplitude and complex motions. Here, a strategy is reported to build a light-responsive liquid-crystalline polyurethane elastomer by phototriggered overcrowded alkene-based molecular motors. A trifunctional molecular motor modified with an ethylene glycol spacer on the rotor and stator functions as a crosslinker and unidirectional stirrer that amplifies molecular motion into macroscopic movement. The shape-programmable polymeric film presents superior mechanical properties and characteristic shape-memory effect. Furthermore, diverse modes of motions including bending, unwinding, and contracting with tunable actuation speed over a wide range are achieved. Such research is hoped to pave a new way for the design of advanced light-responsive soft actuators and robots.

9.
Artículo en Inglés | MEDLINE | ID: mdl-37506006

RESUMEN

Epilepsy is one of the most common neurological diseases. Clinically, epileptic seizure detection is usually performed by analyzing electroencephalography (EEG) signals. At present, deep learning models have been widely used for single-channel EEG signal epilepsy detection, but this method is difficult to explain the classification results. Researchers have attempted to solve interpretive problems by combining graph representation of EEG signals with graph neural network models. Recently, the combination of graph representations and graph neural network (GNN) models has been increasingly applied to single-channel epilepsy detection. By this methodology, the raw EEG signal is transformed to its graph representation, and a GNN model is used to learn latent features and classify whether the data indicates an epileptic seizure episode. However, existing methods are faced with two major challenges. First, existing graph representations tend to have high time complexity as they generally require each vertex to traverse all other vertices to construct a graph structure. Some of them also have high space complexity for being dense. Second, while separate graph representations can be derived from a single-channel EEG signal in both time and frequency domains, existing GNN models for epilepsy detection can learn from a single graph representation, which makes it hard to let the information from the two domains complement each other. For addressing these challenges, we propose a Weighted Neighbour Graph (WNG) representation for EEG signals. Reducing the redundant edges of the existing graph, WNG can be both time and space-efficient, and as informative as its less efficient counterparts. We then propose a two-stream graph-based framework to simultaneously learn features from WNG in both time and frequency domain. Extensive experiments demonstrate the effectiveness and efficiency of the proposed methods.


Asunto(s)
Epilepsia , Ríos , Humanos , Algoritmos , Procesamiento de Señales Asistido por Computador , Epilepsia/diagnóstico , Convulsiones/diagnóstico , Electroencefalografía/métodos
10.
J Cancer Res Ther ; 19(1): 144-149, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37006055

RESUMEN

Immunotherapy is a novel treatment option for various types of cancers. However, the optimal timing for response evaluation has not been well defined. Here, we present a gastric cancer (GC) patient with microsatellite instability-high who experienced recurrence 5 years and 11 months after radical gastrectomy. Then, the patient was treated with radiotherapy, targeted drugs, and immunotherapy. Immunotherapy resulted in 5 months of continuous progression, accompanied by significantly increased tumor marker CA19-9. However, the patient exhibited a satisfactory response without altering the treatment. Based on this, we hypothesized that some persistent progression with elevated tumor markers, known as pseudoprogression (PsP), might be observed in patients with recurrent GC during immunotherapy. This process might be prolonged, but if the treatment is continued, it will eventually produce remarkable therapeutic effects. PsP might challenge the globally accepted immune response evaluation criteria for solid tumors.


Asunto(s)
Adenocarcinoma , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/terapia , Progresión de la Enfermedad , Recurrencia Local de Neoplasia/terapia , Adenocarcinoma/terapia , Inmunoterapia/métodos
11.
Molecules ; 28(4)2023 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-36838878

RESUMEN

With the switchability between transparent and light-scattering states, polymer-dispersed liquid crystals (PDLC) are widely used as smart windows, flexible display devices, projectors, and other devices. In outdoor applications, in addition to excellent electro-optical properties, there is also a high demand for film stability. In this work, a PDLC film with high mechanical strength and structural stability is prepared that can maintain stability at 80 °C for 2000 h. By choosing liquid crystals with a wide temperature range, adopting acrylate polymer monomers containing hydroxyl groups, and adjusting the polymer content, the PDLC film can work well from -20 °C to 80 °C. On this basis, the effects of the introduction of rigid monomers on the mechanical properties and electro-optical properties of PDLC films are investigated.


Asunto(s)
Cristales Líquidos , Polímeros
12.
Molecules ; 28(2)2023 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-36677812

RESUMEN

A novel liquid-crystal compound of more than 99.95% purity with high performance (such as a high clearing point, large dielectric anisotropy, high optical anisotropy, low viscosity, and large elastic constants) was designed and synthesized according to the fringe-field switching thin-film-transistor-liquid-crystal display requirements (FFS-TFT). Then, a mixed liquid-crystal material suitable for an FFS-TFT display was developed by mixing this compound with other reported compounds, developing a product whose quality was that of the highest level of similar foreign products and which fully met the customer's use requirements (BOE), and thus able to completely replace similar imported materials.


Asunto(s)
Cristales Líquidos , Anisotropía
13.
ACS Appl Mater Interfaces ; 15(1): 2228-2236, 2023 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-36579944

RESUMEN

Reverse-mode polymer-stabilized liquid crystal (PSLC) films have wide applications in smart windows for cars as well as buildings and dimming glasses due to their low haze, low energy consumption, and better safety in case of emergency power off. However, PSLC films usually have poor stability of electro-optical properties due to their low polymer content (ca. 5 wt %), and it still remains a challenging task to improve the stability and processability by increasing the polymer content in PSLC as the driving voltage might dramatically increase. In this work, a reverse-mode PSLC film with polymer walls was prepared, which showed excellent stability of electro-optical properties even after 150 000 cycles. The film was prepared through polymerization with a photomask, in which the monomers concentrated on specific areas to form patterned polymer walls. In this way, the polymer content could be increased dramatically and the anchoring effect would not be too strong, thus avoiding a sharp increase in the driving voltage. As a result, the desired reverse-mode film with high stability, relatively low driving voltage, and high contrast ratio was obtained. The effects of monomer compositions, curing temperature, UV light intensity, and the pattern of the photomask on the microstructures, as well as electro-optical performances of the films were carefully studied. This work provides a new idea for the preparation of reverse-mode electrically switchable light-transmittance controllable films with excellent stability and good electro-optical performance, which would broaden their application in smart cars, building windows, and dimming glasses for light management and potential energy saving.

14.
Materials (Basel) ; 15(24)2022 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-36556644

RESUMEN

Polylactic acid (PLA)/poly(ε-caprolactone) (PCL) blends have exhibited good shape memory properties and degradable characteristics in various 4D printing fields such as biomedicine, flexible electronics, and soft robotics, where the service temperature fluctuates easily by environment temperature and polymer characteristics. In this work, printed PLA/PCL 4D samples with different infill densities were prepared by material extrusion printing of pre-extruded filaments and characterized under different temperatures. The results show that the microstructures of printed samples are not influenced by printing process and have similar unique orientation as that of filaments. The thermal properties are stable and show obvious phase transition temperatures, while the mechanical properties decrease slightly in low temperature region and then decrease rapidly when temperature is over 60 °C. The increase in infill density can further improve the storage modulus more than 40% and have no significant influence on the thermal properties. The printed samples also exhibit good shape memory performances with fast recovery speeds less than 22 s. Furthermore, a two-step model is provided to predict the effective modulus of printed PLA/PCL samples and agrees well with experimental data. The results prove that temperature and infill density have different influences on the thermal, mechanical and shape memory properties of PLA/PCL blends.

15.
Angew Chem Int Ed Engl ; 61(50): e202213915, 2022 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-36259390

RESUMEN

Design and fabrication of advanced security label showing superior performance in data encryption has attracted tremendous scientific interests. Especially, multifunctional optical labels capable of storing distinct information in different modes are highly demanded. Here, a fluorescent cholesteric liquid crystalline network (CLCN) film with programmable visible patterns and photo-rewritable fluorescent patterns was designed and prepared. The visible patterns were fixed by helical network and the colors of visible patterns were tunable by changing relative humidity (RH). The fluorescent patterns originated from dynamic isomerization of fluorescent hydrazones, exhibiting highly thermal stability and switching-ability controlled by light. The orthogonal construction of visible and fluorescent pattern enabled the novel CLCN to encrypt distinct information in reflective mode and in emissive mode, indicating its potential in anti-counterfeiting and information encryptions.

16.
Adv Mater ; 34(40): e2109800, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35732437

RESUMEN

Design and fabrication of macroscopic functional devices by molecular engineering is an emerging and effective strategy in exploration of advanced materials. Photoresponsive overcrowded alkene-based molecular motor (OAMM) is considered as one of the most promising molecular machines due to the unique rotary motion driven by light with high temporal and spatial precision. Amplifying the molecular rotary motions into macroscopic behaviors of photodirected systems links the molecular dynamics with macroscopic motions of materials, providing new opportunities to design novel materials and devices with a bottom-up strategy. In this review, recent developments of the light-responsive liquid crystal system triggered by OAMM will be summarized. The mechanism of amplification effect of liquid crystal matrix will be introduced first. Then progress of the OAMM-driven liquid crystal materials will be described including light-controlled photonic crystals, texture-tunable liquid crystal coating and microspheres, photoactuated soft robots, and dynamic optical devices. It is hoped that this review provides inspirations in design and exploration of light-driven soft matters and novel functional materials from molecular engineering to structural modification.

17.
ACS Appl Mater Interfaces ; 14(15): 17869-17877, 2022 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-35384664

RESUMEN

Liquid crystalline polymer (LCP) is a promising candidate in the design and fabrication of intelligent soft materials due to the combination of programmable anisotropy and elasticity. Here, a novel strategy to fabricate reprogrammable humidity-responsive LCP materials enabled by dynamic ionic cross-links were put forward. The prepared LCP film deforms reversibly with the change of relative humidity (RH). However, the humidity responsivity loses after soaking the film into CaCl2 solution because of the lock of hygroscopic groups by the formed ionic bonds. By selectively cross-linking specific regions of the LCP film, distinctive humidity-driven motions of the film could be realized. More interestingly, by the EDTA-2K solution treatment, ionic cross-links can be interrupted, leading the LCP film responsive to humidity again. Thanks to feasibly removable ionic cross-links, the humidity-directed soft actuator was totally reprogrammable. The behavior of the novel actuator could be manipulated by either the mesogens alignment or the spatially ionic treatment, providing a feasible but robust strategy to fabricate complex humidity-driven soft robots.

18.
BMC Pulm Med ; 22(1): 145, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35428280

RESUMEN

BACKGROUND: In this study, we established a chronic obstructive pulmonary disease (COPD) model by stimulating mice with cigarette smoke, and observed the effects of dendritic cells (DCs) overexpressing SOCS1 on Th17, Treg and other related cytokines in peripheral blood, bronchoalveolar lavage fluid and lung tissues of COPD mice. METHODS: After successfully transfecting DCs with overexpressing SOCS1 (DC-SOCS1), the mice were injected with DC-SOCS1 (1 × 106), DC-SOCS1 (2 × 106) and immature DCs (1 × 106) via tail vein on days 1 and 7 of COPD fumigation modeling. After day 28 of modeling, the peripheral blood, BALF and lung tissue samples were extracted from the mice, and the changes of DCs, Th17 and Treg cells and related cytokines were detected by immunohistochemistry, immunofluorescence, HE staining, flow cytometry and ELISA. RESULTS: The results showed that DC-SOCS1 was able to reduce the secretion of pro-inflammatory factors and increase the anti-inflammatory factors in the COPD mice, and the effect of high concentration (2 × 106 DC-SOCS1) was better than low concentration (1 × 106 DC-SOCS1). Moreover, the intervention effect was significant on day 1 compared with day 7. In the mice injected with DC-SOCS1, the expression of CD83, IL-4, Foxp3, and CCR6 was increased on day 1 than those on day 7, while IL-17 and IFN-γ was decreased. CONCLUSIONS: Intervention of COPD mice with high concentrations of DCs-SOCS1 reduced pro-inflammatory factor secretion and attenuated the inflammatory response in COPD. Trial registration Not applicable.


Asunto(s)
Citocinas , Células Dendríticas , Enfermedad Pulmonar Obstructiva Crónica , Proteína 1 Supresora de la Señalización de Citocinas , Linfocitos T Reguladores , Células Th17 , Animales , Citocinas/inmunología , Células Dendríticas/inmunología , Ratones , Enfermedad Pulmonar Obstructiva Crónica/inmunología , Proteína 1 Supresora de la Señalización de Citocinas/inmunología , Linfocitos T Reguladores/inmunología , Células Th17/inmunología
19.
Small Methods ; 6(5): e2200269, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35398983

RESUMEN

Design and fabrication of freestanding chiro-photonic crystal film with the ability to change color over the whole visible light spectrum is appealing for anticounterfeiting technology and smart labels. Utilizing a newly synthesized light-responsive molecular motor functionalized with cholesterol (chol-MM) on the rotor, novel light-controlled photonic crystal is prepared by doping the novel chol-MM into liquid crystals (LCs). Thanks to the liquid crystalline cholesterol substituent, the chol-MM can be triggered by visible light (420 nm). At the same time, the miscibility of chol-MM in LC matrix is significantly enhanced. Integrating the chol-MM with thermochromic hydrogen-bonded LC matrix, thermal and light dual-responsive cholesteric LC (CLC) material is prepared, in which the nanoscale helical pitch is tunable by photo-induced molecular motions of chol-MM. More importantly, utilizing UV-initiated polymerization of the visible light-modulated CLC material, structural colored photonic crystal films with arbitrary colorful patterns are fabricated. Such freestanding helical nanostructured labels have potential in the application of encrypted communication and anticounterfeiting.


Asunto(s)
Cristales Líquidos , Óptica y Fotónica , Colesterol/química , Cristales Líquidos/química , Fotones , Polimerizacion
20.
ACS Appl Mater Interfaces ; 14(14): 16764-16771, 2022 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-35352930

RESUMEN

Dynamic photonic crystals with tunable structural colors have been a hot topic in the research of anticounterfeiting devices, decoration, and detection. In this work, we prepared cholesteric liquid crystalline network (CLCN)-based photonic crystals that present humidity- and SO2 gas-responsive behaviors. The covalently cross-linked CLCN film presents humidity-responsive color changes due to the swelling/deswelling of the matrix under different humidity conditions. When treating the CLCN film with SO2 gas, the carboxylic salt converted to the acid and the film was not able to respond to the humidity change anymore. The mechanism of the SO2 gas-gated humidity responsiveness of the CLCN film was characterized. It was found that the acidic gas caused changes of pH, resulting in the conversion of the salt to acid and alteration of the surface property. The influence of concentration of SO2 gas and pH on humidity responsiveness of the CLCN film was investigated. We hope that this method provides inspirations for the design and fabrication of visualized pH and acidic gas detectors.

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