UV Light Exposure Research Articles

Cysteine-Activatable Near-Infrared Fluorescent Probe for Dual-Channel Tracking Lipid Droplets and Mitochondria in Epilepsy.

Dual-channel fluorescent probes could respond to a specific target and emit different wavelengths of fluorescence before and after the response. Such probes could alleviate the influence caused by the variation of the probe concentration, excitation intensity, and so on. However, for most dual-channel fluorescent probes, the probe and fluorophore faced spectral overlap, which reduced sensitivity and accuracy. Herein, we introduced a cysteine (Cys)-responsive and near-infrared (NIR) emissive AIEgen (named TSQC) with good biocompatibility to dual-channel monitor Cys in mitochondria and lipid droplets (LDs) during cell apoptosis through wash-free fluorescence bio-imaging. TSQC can label mitochondria with bright fluorescence around 750 nm, and after reacting with Cys, the reaction product TSQ could spontaneously target LDs with emissions around 650 nm. Such spatially separated dual-channel fluorescence responses could significantly improve detection sensitivity and accuracy. Furthermore, the Cys-triggered dual-channel fluorescence imaging in LDs and mitochondria during apoptosis induced by UV light exposure, H2O2, or LPS treatment is clearly observed for the first time. Besides, we also report here that TSQC can be used to image subcellular Cys in different cell lines by measuring the fluorescence intensities of different emission channels. In particular, TSQC shows superior utility for the in vivo imaging of apoptosis in acute and chronic epilepsy mice. In brief, the newly designed NIR AIEgen TSQC can respond to Cys and separate two fluorescence signals to mitochondria and LDs, respectively, to study Cys-related apoptosis.

Ag2CO3-Based Photocatalyst with Enhanced Photocatalytic Activity for Endocrine-Disrupting Chemicals Degradation: A Review

Endocrine-disrupting chemicals (EDCs) in the aquatic environment have garnered a lot of attention during the past few years. Due to their toxic behavior, which interferes with endocrine functions in both humans and aquatic species, these types of compounds have been recognized as major polluting agents in wastewater effluents. Therefore, the development of efficient and sustainable removal methods for these emerging contaminants is essential. Photocatalytic removal of emerging contaminants using silver carbonate (Ag2CO3)-based photocatalyst is a promising process due to the unique characteristics of this catalyst, such as absorption of a larger fraction of the solar spectrum, wide band gap, non-toxicity, and low cost. The photocatalytic performance of Ag2CO3 has recently been improved through the doping of elements and optimization variation of operational parameters resulting in decreasing the rate of electron–hole pair recombination and an increase in the semiconductor’s excitation state efficiency, which enables the degradation of contaminants under UV or visible light exposure. This review summarized some of the relevant investigations related to Ag2CO3-based photocatalytic materials for EDC removal from water. The inclusion of Ag2CO3-based photocatalytic materials in the water recovery procedure suggests that the creation of a cutting-edge protocol is essential for successfully eliminating EDCs from the ecosystem.

Stability Kinetics of Anthocyanins of Grumixama Berries (Eugenia brasiliensis Lam.) during Thermal and Light Treatments.

Grumixama (Eugenia brasiliensis Lam.) are red-colored fruits due to the presence of anthocyanins. In this paper, anthocyanin-rich extracts from grumixama were submitted to different temperatures and light irradiations, with the aim of investigating their stabilities. The thermal stability data indicated that a temperature range from 60 to 80 °C was critical to the stability of the anthocyanins of the grumixama extracts, with a temperature quotient value (Q10) of 2.8 and activation energy (Ea) of 52.7 kJ/mol. The anthocyanin-rich extracts of grumixama fruits showed the highest stability during exposure to incandescent irradiation (50 W), followed by fluorescent radiation (10 W). The t1/2 and k were 59.6 h and 0.012 h-1 for incandescent light, and 45.6 h and 0.015 h-1 for fluorescent light. In turn, UV irradiation (25 W) quickly degraded the anthocyanins (t1/2 = 0.18 h and k = 3.74 h-1). Therefore, grumixama fruits, and their derived products, should be handled carefully to avoid high temperature (>50 °C) and UV light exposure in order to protect the anthocyanins from degradation. Furthermore, grumixama fruits showed high contents of anthocyanins that can be explored as natural dyes; for example, by food, pharmaceutical and cosmetic industries. In addition, the results of this study may contribute to the setting of processing conditions and storage conditions for grumixama-derived fruit products.

Biopolymer Non-Parametric Analysis: A Degradation Study under Accelerated Destructive Tests.

The degradation of biopolymers such as polylactic acid (PLA) has been studied for several years; however, the results regarding the mechanism of degradation are not completely understood yet. PLA is easily processed by traditional techniques including injection molding, blow molding, extrusion, and thermoforming; in this research, the extrusion and injection molding processes were used to produce PLA samples for accelerated destructive testing. The methodology employed consisted of carrying out material testing under the guidelines of several ASTM standards; this research hypothesized that the effects of UV light, humidity, and temperature exposure have a statistical difference in the PLA degradation rate. The multivariate analysis of non-parametric data is presented as an alternative to multivariate analysis, in which the data do not satisfy the essential assumptions of a regular MANOVA, such as multivariate normality. A package in the R software that allows the user to perform a non-parametric multivariate analysis when necessary was used. This paper presents a study to determine if there is a significant difference in the degradation rate after 2000 h of accelerated degradation of a biopolymer using the multivariate and non-parametric analyses of variance. The combination of the statistical techniques, multivariate analysis of variance and repeated measures, provided information for a better understanding of the degradation path of the biopolymer.

Biopolymer templated strategized greener protocols for fabrication of ZnO nanostructures and their application in photocatalytic technology for phasing out priority pollutants.

Zinc oxide (ZnO) nanostructures have been successfully synthesized via template-assisted and template-free route using three different synthetic methods, i.e., sonochemical, mechanochemical, and hydrothermal. Biopolymer xanthan gum (XG) served as sacrificial template for ZnO synthesis as provided the surface for the growth of nanostructures in a controlled manner. The employment of multifarious synthetic techniques resulted in fabrication of ZnO nanoparticles with diverse morphologies such as needle shaped, hexagonal, and spherical particles. Further, the template-assisted protocols generated thermally stable highly crystalline nanostructures along with high surface area, larger pore size, and low band gap energies in contrast to template-free protocol. The structural and other physicochemical studies were manifested by XRD, N2 adsorption desorption, FESEM, TGA, and UV-Vis spectral analysis. The template-assisted ZnO nanostructures were explored as a potential photocatalyst for the catalytic degradation of emerging pollutants, i.e., triclosan (TCS) and imidacloprid (IMD) under the exposure of UV light. The products formed during the photocatalytic reaction were monitored by UV-Vis spectroscopy and HPLC. The results obtained revealed the high catalytic efficiency of ZnO synthesized via template-assisted sonochemical method for TCS (99.60%) and IMD (96.09%) which is attributed to the high surface area and lower band gap energy of the catalyst. The high catalytic potential of the sonochemically synthesized ZnO also substantiated from the kinetic data as high-rate constant was obtained. Thus, the template-assisted protocols developed led to preparation of nanostructures having tailored properties for efficient photocatalysis and can rapidly degrade selected emerging contaminants such as personal care products and organophosphate pesticides. Hence, environment-friendly synthesized photocatalyst can be appropriately employed to wastewater treatment contaminated with emerging pollutants.

Synthesis and lithographic properties of positive-tone poly(benzoxazole)s by the effect of amine end-cappers

Positive-tone photosensitive poly(o-hydroxyamide) (PHA) precursors were synthesized from the polycondensation reaction of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (Bis-AP-AF), 4,4’-oxybisbenzoyl chloride (OBC) and three mono-functional amines as end-cappers. The synthesized PHA precursors were characterized and converted to polybenzoxazoles (PBOs) by thermal cyclization reaction. The photoresist formulations composed of the prepared PHA precursor and diazonaphthoquinone (DNQ) photoactive compound were prepared, and the photolithographic properties of the photoresist formulations were investigated by UV light irradiation, followed by a 2.38 wt.% tetramethylammonium hydroxide (TMAH) solution treatment in terms of the chemical structure of end-cappers. The dissolution rate at 2.38 wt.% TMAH solution by various UV light exposure doses and the shrinkage ratio by thermal cyclization of micro-patterns by UV light irradiation and developing process from the photoresist formulations are affected by the chemical structure of end-cappers.

Controlled Production of Carnosic Acid and Carnosol in Cell Suspensions of Lepechinia meyenii Treated with Different Elicitors and Biosynthetic Precursors.

Lepechinia meyenii is a medicinal plant specialized in the biosynthesis of different types of antioxidants including the diterpenes carnosic (CA) acid and carnosol (CS). Herein we present the results of plant tissue culture approaches performed in this medicinal plant with particular emphasis on the generation and evaluation of a cell suspension system for CA and CS production. The effect of sucrose concentration, temperature, pH, and UV-light exposure was explored. In addition, diverse concentrations of microbial elicitors (salicylic acid, pyocyanin, Glucanex, and chitin), simulators of abiotic elicitors (polyethylene glycol and NaCl), and biosynthetic precursors (mevalonolactone, geranylgeraniol, and miltiradiene/abietatriene) were evaluated on batch cultures for 20 days. Miltiradiene/abietatriene obtainment was achieved through a metabolic engineering approach using a recombinant strain of Saccharomyces cerevisiae. Our results suggested that the maximum accumulation (Accmax ) of CA and CS was mainly conferred to stimuli associated with oxidative stress such as UV-light exposure (Accmax , 6.2 mg L-1 ) polyethylene glycol (Accmax , 6.5 mg L-1 ) NaCl (Accmax , 5.9 mg L-1 ) which simulated drought and saline stress, respectively. Nevertheless the bacterial elicitor pyocyanin was also effective to increase the production of both diterpenes (Accmax , 6.4 mg L-1 ). Outstandingly, the incorporation of upstream biosynthetic precursors such as geranylgeraniol and miltiradiene/abietatriene, generated the best results with Accmax of 8.6 and 16.7 mg L-1 , respectively. Optimized batch cultures containing 100 mg L-1 geranylgeraniol, 50 mg L-1 miltiradiene/abietatriene (95 : 5 %) and 5 g L-1 polyethylene glycol treated with 6 min UV light pulse during 30 days resulted in Accmax of 26.7 mg L-1 for CA and 17.3 mg L-1 for CS on days 18-24. This strategy allowed to increase seven folds the amounts of CA and CS in comparison with batch cultures without elicitation (Accmax , 4.3 mg L-1 ).

Degradation of the dye methyl orange using cow and goat milk iron nanoparticles

ABSTRACT Environmental pollution is a global issue, and the contamination of water by dyes is a matter of concern. This work reports an environmentally friendly method for degrading methyl orange dye using iron nanoparticles (INPs) synthesized from pasteurized cow and goat milk and ferric chloride (FeCl3). INPs were synthesized using FeCl3 and milk mixed in a 1:2 (v/v) ratio and subsequently heated at 70 0C. The formation of INPs was monitored by visualizing the color changes. The synthesized NPs were characterized by FTIR, SEM, EDS, TEM, XRD, and XPS. The XRD results showed that INPs were formed and had an amorphous structure. TEM data showed smaller semi-spherical particles with sizes of 8-27 nm, and they were present in an aggregated state. Dye degradation studies were conducted using INP with UV light exposure and H2O2 addition. Both the processes were monitored using UV/Vis scans at different time intervals. The results showed that the degradation of methyl orange was faster in the presence of H2O2 (over 85% efficiency in 60 min) than in the presence of UV light. The current study shows that the INPs formed using milk have the potential to be used as catalysts in azo dye degradation reactions.

Improving the stability of photodoped metal oxide nanocrystals with electron donating graphene quantum dots.

Doped metal oxide nanocrystals are emerging as versatile multi-functional materials with the potential to address several limitations of the current light-driven energy storage technology thanks to their unique ability to accumulate a large number of free electrons upon UV light exposure. The combination of these nanocrystals with a properly designed hole collector could lead to steady-state electron and hole accumulation, thus disclosing the possibility for light-driven energy storage in a single set of nanomaterials. In this framework, it is important to understand the role of the hole collector during UV light exposure. Here we show, via optical absorbance measurements under UV light, that well-defined graphene quantum dots with electron-donating character can act as hole acceptors and improve the stability of the photo-generated electrons in Sn-doped In2O3 nanocrystals. The results of this study offer new insight into the implementation of photo-charged storage devices based on hybrid organic/inorganic nanostructures.

GaN/ZnO hybrid nanostructures for improved photocatalytic performance: One-step synthesis.

Nanostructured semiconductor materials are considered potential candidates for the degradation of textile wastewater via the photocatalytic process. This study aims to produce hexagonal gallium nitride (GaN) nanoplates and zinc oxide (ZnO) nanoparticles in a deionized water environment utilizing a one-step arc discharge process. Detailed characterization of samples has been completed via scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV visible spectroscopy methods. The hybrid nanostructure morphologies consist of nanoplates and nanorods of different sizes. The photoperformance of GaN/ZnO hybrid nanostructures was assessed via the malachite green (MG) dye degradation under UV exposure. Under UV exposure, the degradation yield reached 98% in 60 min. Compared to individual ZnO and GaN nanoparticles, the photocatalytic reaction rate of the GaN/ZnO photocatalyst is 2.2 and 3.6 times faster, respectively. Besides, the GaN/ZnO hybrid nanostructures show excellent photocatalytic stability. The energy consumption of the photocatalytic degradation in the presence of GaN/ZnO hybrid nanostructures was 1.688 kWhL-1. These results demonstrate that the GaN/ZnO hybrid nanostructures with improved photocatalytic activity are a reasonable option for the decomposition of textile wastewater under UV light exposure.

PH-Responsive swimming behavior of light-powered rod-shaped micromotors.

Micromotors have emerged as promising devices for a wide range of applications e.g., microfluidics, lab-on-a-chip devices, active matter, environmental monitoring, etc. The control over the activity of micromotors with the ability to exhibit multimode swimming is one of the most desirable features for many of the applications. Here, we demonstrate a rod-shaped light-driven micromotor whose activity and swimming behavior can easily be controlled. The rod-shaped micromotors are fabricated through the dynamic shadowing growth (DSG) technique, where a 2 μm long arm of titanium dioxide (TiO2) is grown over spherical silica (SiO2) particles (1 μm diameter). Under low-intensity UV light exposure, the micromotors exhibit self-propulsion in an aqueous peroxide medium. When activated, the swimming behavior of micromotors greatly depends on the pH of the medium. The swimming direction, i.e., forward or backward movement, as well as swimming modes like translational or rotational motion, can be controlled by changing the pH values. The observed dynamics has been rationalized using a theoretical model incorporating chemical activity, hydrodynamic flow, and the effect of gravity for a rod-shaped active particle near a planar wall. The pH-dependent translational and rotational dynamics of micromotors provide a versatile platform for achieving controlled and responsive behaviors. Continued research and development in this area hold great promise for advancing micromotors and enabling novel applications in microfluidics, micromachining, environmental sciences, and biomedicine.

Electrochemical sensor of carboxymethyl cellulose and photocatalytic degradation of Navy Blue dye by sonochemically synthesized Titanium oxide nanoparticles

Nanocrystalline titanium oxide nanoparticles (TiO2 NPs) were synthesized by using a low-cost sonochemical method. TiO2 NPs exhibited anatase phase and an average crystallite size of 40.64 ​nm, according to a powder X-ray diffraction (PXRD) investigation. SEM and TEM images revealed spherical shape, with asymmetric geometries for TiO2 NPs. The micrographs thoroughly corroborated the plate-like structure for the NPs. In order to confirm the average energy gap of TiO2 NPs, diffused reflectance spectroscopy (DRS) via Kubelka-Monk function was applied (3.66 ​eV). Navy blue dye was used to study the photocatalytic properties of NPs and discovered to be triggered at 590.9 ​nm. The photodegradation rate of NB dye decolorized up to 74.04% after 120 ​min of UV light exposure. The first order kinetics was indicated by a linear relationship between log C/Co and k. The demonstrated rates of photodecoloration for NB under UV light in the presence of scavengers AgNO3, ethanol, and ethylenediamine tetraacetic acid (EDTA), were found to be 65.50%, 61.46%, and 57.33%, respectively. Using the carbon paste electrodes and cyclic voltammetry (CV) in 0.1 ​N HCl solution, the electrochemical characteristics of the obtained sample were studied. The carboxymethyl cellulose sensor made from TiO2 NPs demonstrated a remarkable sensitivity of 0.08 A. The results showed a high recovery for lead with low% of RSD values. The TiO2 electrode is a promising electrode material for sensing applications due to its outstanding electrochemical performance.

Gastropods Colour Patterns in Cassiopids and Naticids from Romualdo Formation, Araripe Basin, Northeast Brazil

The phylum Mollusca includes one of the most beautiful examples of colour patterns in present-day shells. However, they are rare in the fossil record because they demand excellent fossilization. In Brazil, colour patterns in fossil mollusk shells are recorded in gastropods Natica aff. bulbulus White, 1887 from the Riachuelo Formation (Aptian-Albian), Sergipe-Alagoas Basin. This paper presents the first gastropod shells from the Romualdo Formation with colour patterns, visible under natural and UV light, belonging to the families Naticidae and Cassiopidae, collected at Santo Antônio outcrop municipality of Exu, Pernambuco and, Pinheiro and Serra do Mãozinha sites, municipality of Missão Velha and Romualdo site, municipality of Crato, Ceará. Among the cassiopids more than 100 specimens were tested, with 1/3 of them showing a residual colour pattern under UV light exposure, after chemical preparation. They correspond to the species Paraglauconia (Diglauconia) araripensis (Beurlen, 1964), Paraglauconia (Diglauconia) lyrica Maury, 1934, Gymnentome (Gymnentome) carregozica (Maury, 1934) and Gymnentome (Gymnentome) romualdoi Beurlen, 1964. The colour pattern is virtually similar in both genera, with fluorescent stripes on a dark background, showing the taxonomic similarity between them. As for the naticids, about 20 specimens were collected and 15 show good preservation, observing the visible colour pattern under natural light in Natica sp. and Euspira sp.; both new taxa for the Araripe Basin. The residual colour pattern in naticids ranges from spiral stripes to sigmoidal lines and blotches of brown and yellowish tones on a paler background, as observed in fossil species of the same family in the Cenozoic. The new occurrences increase the fossiliferous diversity of mollusks of the Romualdo Formation and extend the understanding of the diversity of colouration patterns of Lower Cretaceous gastropods.

EFFECT OF TEMPERATURE AND ULTRAVIOLET RADIATION ON GROWTH AND PATHOGENICITY OF Metarhizium anisopliae

The efficacy of entomopathogenic fungi in the field depends on the influence of various environmental factors, including temperature and level of exposure to UV light. It is hypothesized that temperature and level of UV light exposure of Metarhizium anisopliae (Hypocreales, Clavicipiceae) may affect its efficiency in controlling the sweetpotato weevil (Cylas formicarius, Fabricius; Coleoptera, Brentidae). The objective of this study was to evaluate the influence of temperature and ultraviolet light radiation on the growth and pathogenicity of different native strains of Cuban origin of the M. anisopliae Sorokin complex with biological activity against C. formicarius. Colony diameter was measured at 28, 30, 32 and 34 °C temperature and exposed to ultraviolet light (254 nm) for 10, 15, 20, 30, 30, 60 and 120 minutes. Under laboratory conditions, the percentage germination of conidia of strains LBMa-11, LBM-30, LBM-41 and LBM-146 was determined, as well as their pathogenic capacity by means of bioassays with adults of C. formicarius in terms of the percentage of cumulative mortality and the mean lethal time (TL50). Results proved that temperature and UV light affect the ability of M. anisopliae to control C. formicarius. A delay in cumulative mortality was detected for all strains exposed to UV light, with an increase in TL50. The optimum temperature range was between 28 and 30 °C. The strain LBM-127 showed the highest sensitivity to temperature, LBMa-11 the highest tolerance to UV light, and LBM-146 was the most virulent according to Probit regression analysis.

Outstanding performance of gelatin as folic acid carrier: Assessment of photoprotection, bioaccessibility and gelling properties of the protein

Protein-based carriers are important tools for the delivery of bioactive molecules. The objective of this work is to assess gelatin as folic acid carrier, a water-soluble vitamin with numerous fundamental biological functions. In particular, the aim of this research is to assess how this interaction affects some important properties of gelatin, to what extent it protects folic acid from degradation caused by UV light exposure and how bioaccessible the vitamin is after in vitro gastro-duodenal digestion. Firstly, it was determined that the interaction with gelatin (2.5%) at pH 3 was more efficient to avoid its degradation. In this system, it was verified that the vitamin was released from the protein carrier during the duodenal stage and would be bioaccessible in this site of absorption. Finally, the effect of folic acid on the gelling properties of this protein was analyzed, given the importance when used as food ingredient. No relevant differences were observed in the rheological and functional parameters due to the presence of the vitamin, which would allow a wide application of the developed carrier.

Effective Fluorescence Detection of Hydrazine and the Photocatalytic Degradation of Rhodamine B Dye Using CdO-ZnO Nanocomposites

CdO-ZnO nanocomposites were synthesized using a simple solution approach, and several characterization approaches were used to examine the morphological, structural, phase, vibrational, optical, and compositional properties of these CdO-ZnO nanocomposites. The FESEM study revealed the development of aggregates ranging in size from 250 nm to 500 nm. These aggregates were composed of various CdO-ZnO nanoparticle shapes and sizes. XRD investigation revealed hexagonal wurtzite and cubic phases in ZnO and CdO, respectively. The crystal size was 28.06 nm. The band-gap energy of the produced nanocomposites was calculated using UV-Vis analysis and was determined to be 2.55 eV. The CdO-ZnO nanocomposites were employed as a promising material for the effective fluorescence detection of hydrazine and for the quicker photocatalytic degradation of Rhodamine B (RhB) dye. Within 120 min of UV light exposure, the RhB dye was 87.0% degraded in the presence of the CdO-ZnO nanocomposites and the degradation process followed zero-order and pseudo-first-order kinetics. Based on 3σ IUPAC criteria, the limit of detection for fluorescent hydrazine sensing was 28.01 µM. According to the results presented here, CdO-ZnO nanocomposites may function as both a photocatalyst for the breakdown of organic pollutants as well as an effective luminous sensor for the detection of harmful analytes.

Silicon-carbide (SiC) nanocrystal as technology and characterization and its applications in photo-stabilizers of Teflon

Polytetrafluoroethylene (PTFE) was mixed with silicon carbide nanoparticles in various quantities to create thin films. Long-term UV light exposure to the PTFE films was used to study the effects of SiC NPs as a photo-stabilizer by assessing changes in weight loss and surface shape. Comparing PTFE films with various SiC NP concentrations to the blank film, very little variation was seen. AFM and optical microscopy were also used to analyze the surface morphology of films. When PTFE films with additives were compared to blank film, there were hard to observe any negative changes brought due to photo-degradation. Additionally, the surfaces appeared more uniformly smooth hence SiC NPs work well as photo-stabilizers to impede photo-degradation, particularly 0.0005 gm weight. Silicon carbide nanoparticles absorb ultraviolet light, bind polymeric chains, scavenge radical moieties, and degrade peroxide residues.

Target Analyte Interaction with a New Julolidine Coupled Benzoxazole‐based Dyad: A combined Photophysical, Theoretical (DFT), and Bioimaging Study

AbstractA julolidine‐coupled benzoxazole‐based fluorescent chemosensor (BPOZ) is designed and developed to investigate the different target analyte interactions spectroscopically. Based on the ′off‐on‐off′ photoluminescence mechanism, the as‐prepared BPOZ is used for sequentially detecting Zn2+ and HSO4− ions, respectively. The UV‐visible absorption and photoluminescence spectral behavior is intramolecular charge transfer (ICT) in nature. When Zn2+ ions bind with BPOZ, its fluorescence is significantly enhanced at 512 nm due to chelation‐enhanced fluorescence. A green color emission is also visible under 365 nm UV light exposure, which is also confirmed by the color chromaticity diagram. Chelation‐enhanced photoluminescence is also manifested in the lifetime decay analysis. Further, it is well supported by different spectroscopic techniques and DFT analysis. In the presence of HSO4− ions, photoluminescence of the Zn2+ chelated BPOZ complex is significantly reduced, rebirthing the free BPOZ. The detection limit of BPOZ for Zn2+ and Zn2+ chelated BPOZ complex towards detecting Zn2+ and HSO4− ions is established to be in the order of nM and μM range, respectively, in the solution phase. Among the various explosive nitroaromatic compounds, picric acid (PA) quenched the emission of the Zn2+ chelated BPOZ complex, and the quenching mechanism is found to be both static and dynamic in nature. Using these chemically prearranged inputs and optical outputs, two inputs, INHIBIT, and three inputs, combinational logic gates have been constructed. The BPOZ chemosensor and Zn2+ chelated BPOZ complex are also employed to map Zn2+ ions and PA in the living cell. The performance of the BPOZ chemosensor and Zn2+ chelated BPOZ complex toward Zn2+ ions and PA proved that it could be exploited as a signal tool for environmental and biological samples.

Fabrication of ultraviolet/thermal-sensitive PMMA/PDMS wrinkle structures and the demonstration as smart optical diffusers

Although smart optical diffusers have received increasing attention for the next generation of flexible optoelectronics, the exploration and fabrication of low-cost ultraviolet/thermal-sensitive optical diffusers are still challenging. In this study, we used a cost-effective method to fabricate flexible PMMA/PDMS wrinkle structures, demonstrating their applicability as tunable ultraviolet/thermal-sensitive optical diffusers. As the temperature gradually increased, the wrinkle wavelength changed slightly while the amplitude decreased. The wrinkle wavelength remained unchanged after UV light exposure, while the wrinkle amplitude decreased with the illumination time. When the fabricated structures were used as optical diffusers, the number of light diffraction pattern rings decreased with the wavelength of the wrinkle structures. Optical diffusers with different wrinkle patterns and the same aspect ratio exhibited different diffusing properties. The number of apertures and the coverage area of the diffused spot gradually decreased when the optical diffuser structure was exposed to heating. Remarkably, the optical diffusers could recover to their original state quickly after cooling. The number of apertures and the coverage area of the diffused spot gradually decreased with UV irradiation time. The prepared PMMA/PDMS wrinkle structures exhibit great potential for intelligent displays, wise medical systems, and other smart devices.

Photochemically Mediated Polymerization of Molecular Furan and Pyridine: Synthesis of Nanothreads at Reduced Pressures.

Nanothreads are emerging one-dimensional sp3-hybridized materials with high predicted tensile strength and a tunable band gap. They can be synthesized by compressing aromatic or nonaromatic small molecules to pressures ranging from 15-30 GPa. Recently, new avenues are being sought that reduce the pressure required to afford nanothreads; the focus has been placed on the polymerization of molecules with reduced aromaticity, favorable stacking, and/or the use of higher reaction temperatures. Herein, we report the photochemically mediated polymerization of pyridine and furan aromatic precursors, which achieves nanothread formation at reduced pressures. In the case of pyridine, it was found that a combination of slow compression/decompression with broadband UV light exposure yielded a crystalline product featuring a six-fold diffraction pattern with similar interplanar spacings to previously synthesized pyridine-derived nanothreads at a reduced pressure. When furan is compressed to 8 GPa and exposed to broadband UV light, a crystalline solid is recovered that similarly demonstrates X-ray diffraction with an interplanar spacing akin to that of the high-pressure synthesized furan-derived nanothreads. Our method realizes a 1.9-fold reduction in the maximum pressure required to afford furan-derived nanothreads and a 1.4-fold reduction in pressure required for pyridine-derived nanothreads. Density functional theory and multiconfigurational wavefunction-based computations were used to understand the photochemical activation of furan and subsequent cascade thermal cycloadditions. The reduction of the onset pressure is caused by an initial [4+4] cycloaddition followed by increasingly facile thermal [4+2]-cycloadditions during polymerization.