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Protracted droughts lasting years to decades constitute severe threats to human welfare across the Indian subcontinent. Such events are, however, rare during the instrumental period (ca. since 1871 CE). In contrast, the historic documentary evidence indicates the repeated occurrences of protracted droughts in the region during the preinstrumental period implying that either the instrumental observations underestimate the full spectrum of monsoon variability or the historic accounts overestimate the severity and duration of the past droughts. Here we present a temporally precise speleothem-based oxygen isotope reconstruction of the Indian summer monsoon precipitation variability from Mawmluh cave located in northeast India. Our data reveal that protracted droughts, embedded within multidecadal intervals of reduced monsoon rainfall, frequently occurred over the past millennium. These extreme events are in striking temporal synchrony with the historically documented droughts, famines, mass mortality events, and geopolitical changes in the Indian subcontinent. Our findings necessitate reconsideration of the region's current water resources, sustainability, and mitigation policies that discount the possibility of protracted droughts in the future.
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Tempestades Ciclônicas , Secas , Condições Sociais , Humanos , Índia , Isótopos de Oxigênio , Chuva , Estações do AnoRESUMO
Fullerene (C60) crystals have attracted considerable attention in the field of optoelectronic devices owing to their excellent performance as n-type semiconductor material. However, a challenge still remains unbeaten as to the continuous crystallization of non-solvated C60 single-crystal films with high coverage and uniform alignment using low-cost solution techniques. Here, a facile bar coating method is used to prepare ribbon-shaped non-solvated C60 crystals with a large area (up to centimeters) and high coverage (>95%) by precisely controlling the crystallization process from specific solvents. Benefiting from the non-solvated crystalline structure, well-distributed thickness, uniform morphological alignment, and crystallographic orientation, organic field-effect transistors fabricated from the C60 single-crystal films exhibit a high average electron mobility of 2.28 cm2 V-1s-1, along with the coefficient of variance (CV) as small as 13.6%. This efficient manufacturing method will lay a strong foundation for C60 single-crystal films to fit into the future high-performance integrated optoelectronic application.
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Inadequate reference databases in RNA-seq analysis can hinder data utilization and interpretation. In this study, we have successfully constructed a high-quality reference transcript dataset, ZjRTD1.0, for Zoysia japonica, a widely-used turfgrass with exceptional tolerance to various abiotic stress, including low temperatures and salinity. This dataset comprises 113,089 transcripts from 57,143 genes. BUSCO analysis demonstrates exceptional completeness (92.4%) in ZjRTD1.0, with reduced proportions of fragmented (3.3%) and missing (4.3%) orthologs compared to prior datasets. ZjRTD1.0 enables more precise analyses, including transcript quantification and alternative splicing assessments using public datasets, which identified a substantial number of differentially expressed transcripts (DETs) and differential alternative splicing (DAS) events, leading to several novel findings on Z. japonica's responses to abiotic stresses. First, spliceosome gene expression influenced alternative splicing significantly under abiotic stress, with a greater impact observed during low-temperature stress. Then, a significant positive correlation was found between the number of differentially expressed genes (DEGs) encoding protein kinases and the frequency of DAS events, suggesting the role of protein phosphorylation in regulating alternative splicing. Additionally, our results suggest possible involvement of serine/arginine-rich (SR) proteins and heterogeneous nuclear ribonucleoproteins (hnRNPs) in generating inclusion/exclusion isoforms under low-temperature stress. Furthermore, our investigation revealed a significantly enhanced overlap between DEGs and differentially alternatively spliced genes (DASGs) in response to low-temperature stress, suggesting a unique co-regulatory mechanism governing transcription and splicing in the context of low-temperature response. In conclusion, we have proven that ZjRTD1.0 will serve as a reliable and useful resource for future transcriptomic analyses in Z. japonica.
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Processamento Alternativo , Temperatura Baixa , Poaceae , Processamento Alternativo/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Poaceae/genética , Estresse Fisiológico/genética , Transcriptoma/genéticaRESUMO
Artificial reefs (ARs) are a preferred option for managers due to their distinctive hydrodynamic properties, which support a highly productive local ecosystem. However, the hydrodynamics characteristics of ARs in natural marine environments have not been conducted. Being the first to explore the spatiotemporal characteristic of flow fields around ARs along tidal cycles in marine environments, this study redefined the upwelling and downwelling of ARs, based on natural vertical velocities, and separated the upwelling into co-direction upwelling and re-direction upwelling, and the downwelling into co-direction downwelling and re-direction downwelling. This study simulated the flow field in the Wanshan ARs area of the Pearl River Estuary along the tidal cycles using the MIKE3-FM. Numerical simulations revealed that (1) co-direction upwelling and co-direction downwelling were the dominant components of the vertical flow field effects of ARs; (2) the areas sum of upwelling and downwelling were largest in the medium water column, with about 1.6 and 1.03 times as large as the bottom and surface water column, respectively, while the fluxes sum of the upwelling and downwelling were largest in bottom water column, with approximately 1.3 and 2.2 times larger than those in the middle and surface water columns; (3) the area and volume of the upwelling and downwelling gradually decreased along neap-spring tide, exhibited significantly negative correlations with current speeds; while the upwelling flux and downwelling flux gradually increased along neap-spring tide; exhibited a significantly positive correlation with current speed; (4) the effects of tide to upwelling and downwelling of AR are forced by the northward velocity of current speed, the net flux of upwelling and downwelling showed a significant positive correlation with the northward velocity of current speed (r = 0.94). These results could provide a reference for assessing the flow field effect of ARs and a guide for the configuration and management of ARs.
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Estuários , Rios , Ecossistema , Recifes de Corais , Hidrodinâmica , Movimentos da ÁguaRESUMO
The prevalence of osteoarthritis (OA) in Tibetans is higher than that in Han, while Tibetans have a habit of drinking brick tea with high fluoride. A cross-sectional study was conducted to explore the association between fluoride exposure in drinking brick tea and OA. All subjects were divided into four groups by the quartiles (Q) of tea fluoride (TF) and urine fluoride (UF). ROC was plotted and OR were obtained using logistic regression model. The prevalence of OA in the Q3 and Q4 group of TF were 2.2 and 2.7 times higher than in the Q1 group, and the prevalence of OA in the Q2, Q3 and Q4 group of UF were 3.2, 3.5, and 4.1 times higher than in the Q1 group. ROC analysis showed the cutoff values were 4.523 mg/day (TF) and 1.666 mg/L (UF). In conclusion, excessive fluoride in drinking brick tea could be a risk factor for developing OA.
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Semicrystalline polymer dielectrics (SPDs) are highly sought-after state-of-the-art dielectric materials. As the disorder in SPDs degrades their electrical properties, homogeneously ordered SPDs are desired. However, complex crystallization behaviors of polymers make such homogeneity elusive. Polymer lamellar single crystals (PLSCs), the most regularly-ordered form of SPDs possible under mild crystallizing conditions, are ideal platforms for understanding and developing high-performance dielectric materials. Here, a typical and widely used SPD, polyethylene (PE) is selected as the model material. We successfully obtained, large, uniform, and high-quality PE PLSCs and devised a non-destructive strategy to construct PE PLSC-based vertical capacitors. These nanometer-thick capacitors exhibit exceptional dielectric properties, with a high breakdown strength of 6.95 MV/cm and a low dielectric constant of 2.14±0.07, that outperform the properties of any existing neat PE. This work provides novel insights into exploring the performance possibility of ordered SPDs and reveals the PLSCs as potential high-performance dielectric materials.
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We report an anomalous structural transformation of a Cu(I) cluster into two different types of copper-silver (CuAg) alloy nanoclusters. Different from previous reports, we demonstrate that under specifically designed reaction conditions, the Ag-doping could induce a substantial growth of the starting Cu15 and a Ag13Cu20 nanocluster was obtained via the unexpected insertion of an Ag13 kernel inside the Cu(I)-S shell. Ag13Cu20 demonstrates high activity to initiate the photopolymerization of previously hard-to-print inorganic polymers in 3D laser microprinting. Interestingly, a slight modification of the reaction condition leads to the formation of another Ag18-xCuxS (8≤x) nanocluster templated by a central S2- anion, which possesses a unique electronic structure compared to conventional template-free CuAg nanoclusters. Overall, this work unveils the intriguing doping chemistry of Cu clusters, as well as their capability to create different types of alloy nanoclusters with previously unobtainable structures and multifunctionality.
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Sensitizing inorganic semiconductors using singlet fission (SF) materials, which produce two excitons from one absorbed photon, can potentially boost their light-to-electricity conversion efficiency. The SF sensitization is particularly exciting for two-dimensional (2D) layered semiconductors with atomically flat surface and high carrier mobility but limited light absorption. However, efficiently harnessing triplet excitons from SF by charge transfer at organic/inorganic interface has been challenging, and the intricate interplay among competing processes remains unresolved. Here, we investigate SF sensitization in high-quality organic/2D bilayer heterostructures featuring TIPS-Pc single crystals. Through transient magneto-optical spectroscopy, we demonstrate that despite an ultrafast SF process in sub-100 fs, a significant fraction of singlet excitons in TIPS-Pc dissociate at the interface before fission, while triplet excitons from SF undergo diffusion-limited charge transfer at the interface in â¼10 ps to ns. Remarkably, the photocharge generation efficiency reaches 126% in heterostructures with optimal thickness, resulting from the competitive interplay between singlet exciton fission, dissociation, and triplet exciton transport. This presents a promising strategy for advancing SF-enhanced 2D optoelectronics beyond the conventional limits.
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BACKGROUND: Bcl-3 is a member of the IκB protein family and an essential modulator of NF-κB activity. It is well established that Bcl-3 is critical for the normal development, survival and differentiation of adaptive immune cells, especially T cells. However, the regulation of immune cell function by Bcl-3 through metabolic pathways has rarely been studied. RESULTS: In this study, we explored the role of Bcl-3 in the metabolism and function of T cells via the mTOR pathway. We verified that the proliferation of Bcl-3-deficient Jurkat T cells was inhibited, but their activation was promoted, and Bcl-3 depletion regulated cellular energy metabolism by reducing intracellular ATP and ROS production levels and mitochondrial membrane potential. Bcl-3 also regulates cellular energy metabolism in naive CD4+ T cells. In addition, the knockout of Bcl-3 altered the expression of mTOR, Akt, and Raptor, which are metabolism-related genes, in Jurkat cells. CONCLUSIONS: This finding indicates that Bcl-3 may mediate the energy metabolism of T cells through the mTOR pathway, thereby affecting their function. Overall, we provide novel insights into the regulatory role of Bcl-3 in T-cell energy metabolism for the prevention and treatment of immune diseases.
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Apoptose , Proteína 3 do Linfoma de Células B , NF-kappa B , Linfócitos T , Humanos , Sobrevivência Celular , Metabolismo Energético , NF-kappa B/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Proteína 3 do Linfoma de Células B/metabolismo , Linfócitos T/metabolismoRESUMO
The long-range ordering of bulk-heterojunctions (BHJs) significantly facilitates exciton diffusion and dissociation as well as charge transport. A feasible bio-inspired strategy to realize such a heterostructure is crystallization in gel media where the growing host crystals incorporate the surrounding guest materials of gel networks. Until now, the host-guest pairs forming ordered BHJs are still very limited and, more importantly, the used gel-network guests are structurally amorphous, spurring investigation toward crystalline gel-networks. Here, single crystals of fullerene and non-fullerene acceptors (NFAs) in poly(3-hexylthiophene) (P3HT) organogel are prepared, forming C60 :P3HT and (5Z,5â³Z)-5,5â³-((7,7â³-(4,4,9,9-tetraoctyl-4,9-dihydro-s-indaceno[1,2-b:5,6-bâ³]dithiophene-2,7-diyl)bis(benzo[c][1,2,5]thiadiazole-7,4-diyl))bis(methanylylidene))bis(3-ethyl-2-thioxothiazolidin-4-one) (O-IDTBR):P3HT BHJs. The crystalline P3HT network penetrates the crystal matrix without significantly disturbing the single crystallinity, resulting in long-range ordered BHJs. This bi-continuous structure, together with an improved overall ordering, contributes to enhanced charge/energy transfer. As a result, photodetectors based on these ordered BHJs exhibit ameliorated responsivity, detectivity, bandwidth, and stability as compared to the conventional BHJs with short-range ordering. Therefore, this work further extends the scope of long-range ordered BHJs toward crystalline polymer donors and NFAs, providing a generally applicable strategy for the design of organic optoelectronic devices with superior performance.
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The incorporation of charged biomacromolecules is widely found in biomineralization. To investigate the significance of this biological strategy for mineralization control, gelatin-incorporated calcite crystals grown from gelatin hydrogels with different charge concentrations along the gel networks are examined. It is found that the bound charged groups on gelatin networks (amino cations, gelatin-NH3 + and carboxylic anions, gelatin-COO- ) play crucial roles in controlling the single-crystallinity and the crystal morphology. And the charge effects are greatly enhanced by the gel-incorporation because the incorporated gel networks force the bound charged groups on them to attach to crystallization fronts. In contrast, ammonium ions (NH4 + ) and acetate ions (Ac- ) dissolve in the crystallization media do not exhibit the similar charge effects because the balance of attachment/detachment make them more difficult to be incorporated. Employing the revealed charge effects, the calcite crystal composites with different morphologies can be flexibly prepared.
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The Younger Dryas (YD), arguably the most widely studied millennial-scale extreme climate event, was characterized by diverse hydroclimate shifts globally and severe cooling at high northern latitudes that abruptly punctuated the warming trend from the last glacial to the present interglacial. To date, a precise understanding of its trigger, propagation, and termination remains elusive. Here, we present speleothem oxygen-isotope data that, in concert with other proxy records, allow us to quantify the timing of the YD onset and termination at an unprecedented subcentennial temporal precision across the North Atlantic, Asian Monsoon-Westerlies, and South American Monsoon regions. Our analysis suggests that the onsets of YD in the North Atlantic (12,870 ± 30 B.P.) and the Asian Monsoon-Westerlies region are essentially synchronous within a few decades and lead the onset in Antarctica, implying a north-to-south climate signal propagation via both atmospheric (decadal-time scale) and oceanic (centennial-time scale) processes, similar to the Dansgaard-Oeschger events during the last glacial period. In contrast, the YD termination may have started first in Antarctica at â¼11,900 B.P., or perhaps even earlier in the western tropical Pacific, followed by the North Atlantic between â¼11,700 ± 40 and 11,610 ± 40 B.P. These observations suggest that the initial YD termination might have originated in the Southern Hemisphere and/or the tropical Pacific, indicating a Southern Hemisphere/tropics to North Atlantic-Asian Monsoon-Westerlies directionality of climatic recovery.
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Marine ranching has been widely considered as a new mode of marine fishery production. Marine ranching ecological security (MRES) is the basis and premise to ensure the sustainable utilization of marine ranching functions. In this study, an MRES early warning system was constructed based on comprehensive marine ranching ecological security index (CMRESI) and system dynamic model to reveal the main factors affecting the development of marine ranching and explore the changes in MRES under different future development scenarios in China's coastal areas from 2011 to 2035. The results showed that (1) the mean CMRESI of China was only 0.3265 and spatial heterogeneity was significant, showing a general security state; (2) coupling and coordination degree of MRES subsystems was high in Jiangsu, Fujian, Shandong, and Guangdong, and resources was a major constraint on the coordinated development of MRES in the study area (63.6%); (3) Under the ecological priority development scenario, the CMRESI will be the highest in 2035; however, 27% of MRES (in Jiangsu, Fujian, and Hainan) will continue to issue serious early warnings. This study could provide a reference for construction planning, management maintenance, and decision-making of marine ranching.
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Ecossistema , Biologia Marinha , China , Pesqueiros , Conservação dos Recursos Naturais/métodosRESUMO
A new kind of piperazine-linked covalent organic framework (COF) was synthesized through the nucleophilic substitution reaction between octaminophthalocyanines and hexadecafluorophthalocyanines. The two-dimensional (2D) frameworks are in tetragonally shaped polygon sheets, which stack in an AA stacking mode to constitute periodically ordered metallophthalocyanine columns and one-dimensional (1D) microporous channels. The piperazine-linked COFs exhibit excellent chemical stability and permanent porosity. By virtue of the neatly arrayed phthalocyanine columns and inbuilt cationic radicals, the piperazine-linked frameworks are highly conductive. The conductivity values of NiPc-NH-CoPcF8 COF reached up to 2.72 and 12.7 S m-1 for pellet and film samples, respectively. Moreover, this p-type conductive COF exhibited a high carrier mobility of 35.4 cm2 V-1 s-1. Both the electric conductivity and carrier mobility set new records for conductive COFs.
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ConspectusSingle crystals of organic semiconductors (OSCs) are believed to have both high mobility and intrinsic flexibility, making them promising candidates for flexible electronic/optoelectronic applications and being consistently pursued by researchers. The van der Waals force in OSC enables low-temperature solution processing of single crystals, but the relatively weak binding energy brings challenges in forming large, uniform, and defect-free single crystals. To promote the study on OSC single crystals, a generalized method that grows high-quality crystals in an easy-to-handle, time/resource-saving, and repeatable manner is apparently necessary. In 2012, Li et al. developed a droplet-pinned crystallization (DPC) method that uses a rather simple strategy to create a steadily receding contact line for the growth of OSC single crystals. Instead of setting up expensive equipment, controlling strict deposition parameters, or waiting for days or weeks for countable crystal seeds, the DPC method offers a time- and cost-effective way to obtain OSC single crystals for further study of the tendency of crystallization, single-crystal mobility, and molecular packing information. The DPC method is primarily a powerful tool for studying the charge-transport mechanisms in OSC single crystals. In pioneering work, high-mobility single crystals of both p-type 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-PEN) and n-type C60 materials were obtained. Driven by the demands from practical applications, we then focused on the general lagging of electron mobility in OSC materials. The ambipolar property of TIPS-PEN was studied, and a strong correlation between electron mobility and polar species (polar solvent residuals and surface hydroxyl groups) was observed. The latter further guided the harvest of electron mobility in a series of OSC materials. Undoubtfully, the facile DPC method accelerated these studies by providing a time-efficient, reliable, and repeatable testing platform. Additionally, flexibility on OSC materials and solvents, where not only one-component but also binary systems were allowed, is another critical integrity of the DPC method. The m-xylene/carbon tetrachloride binary solvent was proven to be efficient for growing ribbon-like C60 single crystals rather than needle-like crystals from typical one-component solvents. Afterward, a variety of OSC materials (including p-type, n-type, and ambipolar ones) and a series of solvents (including aromatic, aliphatic, and polar ones) were studied. The crystallization of OSC single crystals was primarily found at either the top liquid-air interface or the bottom solid-liquid interface. The interactions between OSC molecules and substrate surfaces were deduced as the qualitative determining factor. By utilizing the top interface crystallization, the two-step sequential deposition of single-crystalline OSC heterojunctions was enabled. Moreover, by selecting appropriate pairs of OSC materials that crystallize at separate interfaces, the facile one-step formation of single-crystalline OSC heterojunctions was achieved. The OSC single crystals and heterojunctions (including horizontal, vertical, and bulk heterojunctions) thereof exhibit promising potentials in circuits, photovoltaics, and photodiodes and would probably provide new insights for the future development of organic electronics.
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The development of highly stable covalent organic frameworks (COFs) is extremely compelling for their implementation in practical application. In this work, we rationally designed and synthesized new kinds of ultrastable bimetallic polyphthalocyanine COFs, which are constructed with the dioxin linkage through the nucleophilic aromatic substitution between octahydroxylphthalocyanine and hexadecafluorophthalocyanine. The resulting bimetallic CuPcF8-CoPc-COF and CuPcF8-CoNPc-COF exhibited strong robustness under harsh conditions. The eclipsed stacking mode of metallophthalocyanine units supplies a high-speed pathway for electron transfer. With these structural advantages, both COFs displayed considerable activity, selectivity, and stability toward electrocatalytic CO2 reduction in an aqueous system. Notably, CuPcF8-CoNPc-COF showed a faradaic efficiency of 97% and an exceptionally high turnover frequency of 2.87 s-1, which is superior to most COF-based electrocatalysts. Furthermore, the catalytic mechanism was well demonstrated by using a theoretical calculation. This work not only expanded the variety of dioxin-linked COFs, but also constituted a new step toward their practical use in carbon cycle.
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The poor electrical conductivity of two-dimensional (2D) crystalline frameworks greatly limits their utilization in optoelectronics and sensor technology. Herein, we describe a conductive metallophthalocyanine-based NiPc-CoTAA framework with cobalt(II) tetraaza[14]annulene linkages. The high conjugation across the whole network combined with densely stacked metallophthalocyanine units endows this material with high electrical conductivity, which can be greatly enhanced by doping with iodine. The NiPc-CoTAA framework was also fabricated as thin films with different thicknesses from 100 to 1000â nm by the steam-assisted conversion method. These films enabled the detection of low-concentration gases and exhibited remarkable sensitivity and stability. This study indicates the enormous potential of metallophthalocyanine-based conductive frameworks in advanced stand-off chemical sensors and provides a general strategy through tailor-make molecular design to develop sensitive and stable chemical sensors for the detection of low-concentration gases.
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Bulk-heterojunction (BHJ) blends are commonly used as active materials for optoelectronics. Ordering of molecular packing in blends is critical to their electronic properties, spurring investigation on how to obtain BHJ with long-range ordering. However, the difficulty in controlling crystallization during blending limits the crystallinity. Developing a new strategy instead of conventional blending is, thus, needed. Inspired by biomineralization, here, C60 single-crystals are prepared in organogel matrix of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenvinylene] (MEH-PPV) to form MEH-PPV:C60 composites. Essentially, networks of MEH-PPV are incorporated into growing C60 crystals and penetrate throughout the crystals, resulting in crystal/gel-network interpenetrating composites. Despite the coexistence of MEH-PPV, the C60 crystalline component maintains single-crystallinity and the composite exhibits as BHJ with long-range ordering. Furthermore, compared with blends, the long-range ordered BHJ shows a higher efficiency of charge dissociation and better performance in photodetection, exemplifying the advantage of ordering on organic electronics. Hence, this work provides a new platform to study BHJ with long-range ordering.
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Polymer-templated nematic liquid crystal (LC) holographic gratings via visible-light recording are presented in the presence of reactive mesogens (RMs) and rose bengal (RB)/N-phenylglycine (NPG) photoinitiation systems. By optimizing the concentration of RMs in the polymer-templated LC gratings, the template after being washed out can be refilled with suitable fluidic components. And the dependence of the first-order diffraction efficiency (DE) on the concentration of RB and NPG molecules was discussed in detail. The polarization-dependency of diffraction properties was also investigated. It is revealed that the diffractive behaviors of polymer-templated LC gratings can be dynamically reconfigured by varying temperature or refilling organic solutions with different refractive index (RI). Furthermore, the potential for recording holograms using green light is explored. We expect that the reconfigurable polymer-templated LC gratings fabricated via visible-light interference would provide a facile approach to regulate the diffraction properties of holographic gratings apart from electric field, thus paving a way towards a class of novel anti-counterfeiting devices.
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Correction for 'Optical and electrical effects of plasmonic nanoparticles in high-efficiency hybrid solar cells' by Wei-Fei Fu et al., Phys. Chem. Chem. Phys., 2013, 15, 17105-17111, DOI: 10.1039/C3CP52723A.