Segmenting tourists' motivations via online reviews: An exploration of the service strategies for enhancing tourist satisfaction.

Tourism motivation and satisfaction are classic themes in tourism research. This study combines latent Dirichlet allocation (LDA) and the Censydiam motivation model to analyze online reviews of tourism in Qinghai, China. The aim of this research is to explore tourist motivation through online reviews and provide innovative service suggestions to improve tourist satisfaction. The LDA model initially extracts six main topics from online comments. Then, using the fuzzy analytic hierarchy process (FAHP), it maps the relationship between topics and tourism motivations to propose strategies for enhancing tourists' enjoyment, conviviality, and other motivating factors. Furthermore, we employ the Kano model to evaluate tourists' satisfaction levels regarding these strategies, demonstrating their positive evaluations. Hence, this study provides tourism industry professionals and service designers with an innovative method for understanding tourists' motivations through online reviews, enabling them to design specific services that enhance tourism experiences.

Synthesis of a covalent organic framework with hetero-environmental pores and its medicine co-delivery application.

The topology type and the functionalization of pores play an important role in regulating the performance of covalent organic frameworks. Herein, we designed and synthesized the covalent organic framework with hetero-environmental pores using predesigned asymmetrical dialdehyde monomer. According to the results of structural characterization, crystallinity investigation, and theoretical calculation, the hetero-environmental pores of the obtained framework are regarded as the alternant arrangement. The distinctive hetero pore structure leads the designed material to show more advantages as compared with control materials in loading both hydrophobic and hydrophilic antibiotics for wound healing. This dual-antibiotic strategy can expand the antibacterial range as compared with the single antibiotic one, and reduce the generation of drug resistance. In summary, this strategy for designing covalent organic frameworks with hetero-environmental pores can extend the structural variety and provide a pathway for improving the practical application performance of these materials.

Electrochemical Preparation of Porous Organic Polymer Films for High-Performance Memristors.

Porous organic polymer films (PFs) with intrinsical porosity and tuneable pore environment are ideally suited for application in electronic devices. However, the huge challenges still exist for construction of electronic devices based on PFs owing to lack of robustness, processability, and controllable preparation. Herein, we report the electrochemical preparation of carbazole-based porous organic polymer films (eCPFs) as switchable materials for the memristors. These eCPFs possess the characteristics of controllable thickness/size, high stability, and excellent porosity. Carbazole and cyano groups are introduced into the eCPFs to constructing electron transfer systems. Thus, the memristors constructed based on these eCPFs exhibit excellent switching performance, reliability, and reproducibility. The electrochemically controllable preparation method of porous organic polymer membranes proposed in this paper provides a feasible idea for the developments of electronic devices.

In-situelectrochemical polymerization of aniline on flexible conductive substrates for supercapacitors and non-enzymatic ascorbic acid sensors.

Polyaniline, as a kind of conductive polymer with commercial application prospects, is still under researches in its synthesis and applications. In this work, polyaniline was fabricated on flexible substrates including carbon cloths and polyethylene naphthalate byin situelectropolymerization method. The synthesized flexible electrodes were characterized by scanning electron microscopy, High resolution transmission electron microscope, atomic force microscope, Fourier transform infrared, x-ray diffraction, and x-ray photoelectron spectroscopy. Owing to the conductivity and the reversible redox property, the polyaniline/carbon cloth electrodes show excellent properties such as decent supercapacitor performance and good detection capability toward ascorbic acid. As supercapacitors, the electrodes exhibit a specific capacitance as high as 776 F g-1at a current density of 1 A g-1and a long cycle life of 20 000 times in the three-electrode system. As ascorbic acid sensors, the flexible electrodes demonstrate stable response to ascorbic acid in the range of 1-3000µM with an outstanding sensitivity (4228µA mM-1cm-2), low detection limit (1µM), and a fast response time. This work holds promise for high-performance and low-cost flexible electrodes for both supercapacitors and non-enzymatic ascorbic acid sensors, and may inspire inventions of self-powered electrochemical sensor.

Guiding Uniformly Distributed Li-Ion Flux by Lithiophilic Covalent Organic Framework Interlayers for High-Performance Lithium Metal Anodes.

Lithium (Li) metal anodes are regarded as prospective anode materials in next-generation secondary lithium batteries due to their ultrahigh theoretical capacities and ultralow potentials. However, inhomogeneous lithium deposition and uncontrollable growth of lithium dendrites always give rise to the low lithium utilization, rapid capacity fading, and poor cycling performance. Herein, we design the lithiophilic covalent organic frameworks (COFs) containing preorganized triazine rings and carbonyl groups as the multifunctional interlayer in lithium metal batteries (LMBs). Triazine rings rich in lone pair electrons can act as the donor attracting Li ions, and carbonyl groups serve as Li-anchoring sites effectively coordinating Li ions. These periodic arranged subunits significantly guide uniform Li ion flux distribution, guarantee smooth Li deposition and less lithium dendrite formation. Consequently, the symmetric batteries with COF interlayers exhibit an extraordinary cycling stability for more than 2450 and 1000 h with ultralow polarization voltage of about 12 and 14 mV at 0.5 and 1.0 mA cm-1. Coupling with sulfur (S) cathodes and LiFePO4 (LFP) cathodes, the full cells also demonstrate superb energy density achievement and rate performance. With introducing lithiophilic COFs interlayers, the Li-LFP batteries exhibit high capacity of 150 mAh g-1 and 86% capacity retention after 450 cycles at 0.5 C.

Crosstalk of gut microbiota and serum/hippocampus metabolites in neurobehavioral impairments induced by zinc oxide nanoparticles.

The gut microbiome can be readily influenced by external factors, such as nanomaterials. However, the role of the microbiota-gut-brain axis in nanomaterials-induced neurotoxicity remains largely unknown. In this study, young mice aged 4 weeks were treated with either a vehicle solution or 26 mg kg-1 zinc oxide nanoparticles (ZnONPs) by intragastric administration for 30 days. The neurobehavioral alterations were assessed by the Morris water maze and open field test. Gut microbiota and the metabolites in both blood and hippocampus were detected using 16S rRNA sequencing and liquid chromatography-mass spectrometry metabolomics, respectively. The results demonstrated that oral exposure to ZnONPs resulted in neurobehavioral impairments in young mice, mainly manifested by spatial learning and memory deficits, and the inhibition of locomotor activity. Intriguingly, ZnONPs caused a marked disturbance of the gut microbial composition, but did not alter the α-diversity of the microbiota. The correlation analysis further revealed that neurobehavioral impairments induced by ZnONPs were closely associated with a perturbation in the gut microbiota composition that were specific to changes of neurobehavior-related genes (such as Bdnf and Dlg4), and correlated with serum and hippocampal metabolites. We also identified a unique metabolite [DG(15:0/0:0/22:4n6)] that linked relationships among the gut microbiota, metabolites and neurobehavior-related genes. Taken together, our results illustrated that oral exposure to ZnONPs not only altered the gut microbiome community, but also substantially disturbed the metabolic profiles leading to neurobehavioral impairments via the microbiota-gut-brain axis. These findings will provide a novel view for understanding the neurotoxicity of ZnONPs, and are helpful for identifying potential prevention and treatment strategies.

Iminodiacetic acid-functionalized porous polymer for removal of toxic metal ions from water.

The design of efficient adsorbent with abundant binding sites for heavy metal ions is crucial for developing innovative materials that will remove pollutant metal ions. The high uptake capacity, kinetics, and affinity towards the toxic metals are the key requirements that the materials under invesigation should accomplish. Here we report the synthesis of iminodiacetic acid-functionalized hypercrosslinked polymer (IDA-HCP) for purification of water polluted by toxic metal ions via coordination of carboxylate and amino active sites on the surface of porous polymer. The obtained porous polymer is stable under harsh conditions and the structural features on the polymer work together to help the removal of Pb(II) with 1138 mg g-1 uptake capacity. In the meanwhile, the IDA-HCP reveals reuseability and very promising capture efficiency not only for Pb2+, but also for Hg2+ and Cd2+ from a mixture of Pb2+, Hg2+, Cd2+, Co2+, Fe3+, Zn2+, Mg2+, and Na+ metal ions. This result gives us confidence that the polymer material can solve the pollution problem caused by various metal ions.

Heterozygous disruption of beclin 1 mitigates arsenite-induced neurobehavioral deficits via reshaping gut microbiota-brain axis.

Gut microbiota is intimately involved in numerous aspects of human health. Arsenite expouse can perturb gut microbiota and is linked to increased susceptibility of individual to arsenite-related diseases. However, how microbiome factors influence arsenite-induced neurotoxicity remains largely unknown. In this study, after treating of healthy adult female mice with arsenite via drinking water for 6 months, our results clearly revealed that chronic arsenite exposure not only perturbed the composition of gut microbiota but also caused neurobehavioral dysfunctions, which manifested by learning and memory deficits and anxiety-like behavior. Given that the overactive autophagy directly leads to gut pathological changes, we further assessed whether inhibiton of autophagy by genetic mean could reverse arsenite-induced neurobehavioral dysfunctions. Our results illustrated for the first time that heterozygous disruption of beclin 1, which played a central role in autophagy, alleviated the perturbation of gut microbiome phenotypes induced by arsenite, and ultimately leading to the improvement of neurobehavioral deficits through gut-brain communication. These findings provide a new clue that regulation of autophagy is a potential approach for probing the functional impacts of arsenite on the gut microbiome, and it also may be severed as a way for protection strategies against arsenite neurotoxicity.

Titanium dioxide nanoparticles via oral exposure leads to adverse disturbance of gut microecology and locomotor activity in adult mice.

Titanium dioxide nanoparticles (TiO2NPs) have been widely used as food additives in daily life. However, the impact of oral intake of TiO2NPs on the nervous system is largely unknown. In this study, 7-week-old mice were treated with either vehicle or TiO2NPs suspension solution at 150 mg/kg by intragastric administration for 30 days. Our results demonstrated that oral exposure to TiO2NPs resulted in aberrant excitement of enteric neurons, although unapparent pathological changes were observed in gut. We also found the richness and evenness of gut microbiota were remarkably decreased and the gut microbial community compositions were significantly changed in the TiO2NP-treated group as compared with vehicle controls. Interestingly, oral exposure to TiO2NPs was capable to induce the inhibitory effects on locomotor activity, but it did not lead to significant change on the spatial learning and memory ability. We further revealed the mechanism that TiO2NPs could specifically cause locomotor dysfunction by elevating the excitement of enteric neuron, which might spread to brain via gut-brain communication by vagal pathway. However, inflammation response, enteric neurotransmitter 5-HT and major gut peptides might not be involved in this pathological process. Together, these findings provide valuable insights into the novel mechanism of TiO2NP-induced neurotoxicity. Understanding the microbiota-gut-brain axis will provide the foundation for potential therapeutic or prevention approaches against TiO2NP-induced gut and brain-related disorders.

In vivo imaging of hemodynamic redistribution and arteriogenesis across microvascular network.

OBJECTIVE: Arteriogenesis is an important mechanism that contributes to restoration of oxygen supply in chronically ischemic tissues, but remains incompletely understood due to technical limitations. This study presents a novel approach for comprehensive assessment of the remodeling pattern in a complex microvascular network containing multiple collateral microvessels. METHODS: We have developed a hardware-software integrated platform for quantitative, longitudinal, and label-free imaging of network-wide hemodynamic changes and arteriogenesis at the single-vessel level. By ligating feeding arteries in the mouse ear, we induced network-wide hemodynamic redistribution and localized arteriogenesis. The utility of this technology was demonstrated by studying the influence of obesity on microvascular arteriogenesis. RESULTS: Simultaneously monitoring the remodeling of competing collateral arterioles revealed a new, inverse relationship between initial vascular resistance and extent of arteriogenesis. Obese mice exhibited similar remodeling responses to lean mice through the first week, including diameter increase and flow upregulation in collateral arterioles. However, these gains were subsequently lost in obese mice. CONCLUSIONS: Capable of label-free, comprehensive, and dynamic quantification of structural and functional changes in the microvascular network in vivo, this platform opens up new opportunities to study the mechanisms of microvascular arteriogenesis, its implications in diseases, and approaches to pharmacologically rectify microvascular dysfunction.

Tuning Both Surface Chemistry and Porous Properties of Polymer-Derived Porous Carbons for High-Performance Gas Adsorption.

In this study, we have prepared novel pyrrole-formaldehyde polymers through polymerizing pyrrole and formaldehyde in the mixture solvent of water and ethanol by using hydrochloric acid as a catalyst. The as-synthesized polymers possess a nitrogen content of 6.7 atom % and are composed of spherical particles with the diameter of approximately 1-3 µm. A series of nitrogen-doped porous carbons with high specific surface areas (680-2340 m2 g-1) were successfully obtained through the activation treatment of the polymer spheres. The porous properties and surface chemistry of the as-prepared porous carbons are tuned by choosing different activating agents and changing the activation temperature. The morphology, porous properties, and chemical composition of the obtained nitrogen-doped porous carbons are revealed by various characterization methods, such as scanning electron microscopy, nitrogen sorption measurement, and X-ray photoelectron spectroscopy. The as-prepared nitrogen-doped porous carbons as gas adsorbents display high carbon dioxide uptake capacities of 3.80-5.81 mmol g-1 at 273 K and 1.0 bar. They also show excellent carbon dioxide adsorption capacities (2.40-3.37 mmol g-1 at 1.0 bar) and good gas selectivities (CO2/N2 selectivities of 16.9-70.2) at 298 K.

Isotropic-resolution photoacoustic microscopy with multi-angle illumination.

We have developed photoacoustic microscopy (PAM) with three-dimensional (3D) micron-level spatial resolution. With multi-angle illumination, PAM images from different view angles can be simultaneously acquired for multi-view deconvolution, without the rotation of imaging targets. A side-by-side comparison of this multi-angle-illumination PAM (MAI-PAM) and conventional PAM, which share the same ultrasonic detector, was performed in phantoms and live mice. The phantom study showed that MAI-PAM achieved a high axial resolution of 3.7 µm, which was 10-fold higher than that of conventional PAM and approached the lateral resolution of 2.7 µm. Furthermore, the in vivo study demonstrated that MAI-PAM was able to image the 3D microvasculature with isotropic spatial resolution.

Segmented cell analyses to measure redox states of autofluorescent NAD(P)H, FAD & Trp in cancer cells by FLIM.

Multiphoton FLIM microscopy offers many opportunities to investigate processes in live cells, tissue and animal model systems. For redox measurements, FLIM data is mostly published by cell mean values and intensity-based redox ratios. Our method is based entirely on FLIM parameters generated by 3-detector time domain microscopy capturing autofluorescent signals of NAD(P)H, FAD and novel FLIM-FRET application of Tryptophan and NAD(P)H-a2%/FAD-a1% redox ratio. Furthermore, image data is analyzed in segmented cells thresholded by 2 × 2 pixel Regions of Interest (ROIs) to separate mitochondrial oxidative phosphorylation from cytosolic glycolysis in a prostate cancer cell line. Hundreds of data points allow demonstration of heterogeneity in response to intervention, identity of cell responders to treatment, creating thereby different sub-populations. Histograms and bar charts visualize differences between cells, analyzing whole cell versus mitochondrial morphology data, all based on discrete ROIs. This assay method allows to detect subtle differences in cellular and tissue responses, suggesting an advancement over means-based analyses.

Functional and oxygen-metabolic photoacoustic microscopy of the awake mouse brain.

A long-standing challenge in optical neuroimaging has been the assessment of hemodynamics and oxygen metabolism in the awake rodent brain at the microscopic level. Here, we report first-of-a-kind head-restrained photoacoustic microscopy (PAM), which enables simultaneous imaging of the cerebrovascular anatomy, total concentration and oxygen saturation of hemoglobin, and blood flow in awake mice. Combining these hemodynamic measurements allows us to derive two key metabolic parameters-oxygen extraction fraction (OEF) and the cerebral metabolic rate of oxygen (CMRO2). This enabling technology offers the first opportunity to comprehensively and quantitatively characterize the hemodynamic and oxygen-metabolic responses of the mouse brain to isoflurane, a general anesthetic widely used in preclinical research and clinical practice. Side-by-side comparison of the awake and anesthetized brains reveals that isoflurane induces diameter-dependent arterial dilation, elevated blood flow, and reduced OEF in a dose-dependent manner. As a result of the combined effects, CMRO2 is significantly reduced in the anesthetized brain under both normoxia and hypoxia, which suggests a mechanism for anesthetic neuroprotection. The head-restrained functional and metabolic PAM opens a new avenue for basic and translational research on neurovascular coupling without the strong influence of anesthesia and on the neuroprotective effects of various interventions, including but not limited to volatile anesthetics, against cerebral hypoxia and ischemia.

Multiparametric photoacoustic microscopy of the mouse brain with 300-kHz A-line rate.

Enabling simultaneous high-resolution imaging of the total concentration of hemoglobin ([Formula: see text]), oxygen saturation of hemoglobin ([Formula: see text]), and cerebral blood flow (CBF), multiparametric photoacoustic microscopy (PAM) holds the potential to quantify the cerebral metabolic rate of oxygen at the microscopic level. However, its imaging speed has been severely limited by the pulse repetition rate of the dual-wavelength photoacoustic excitation and the scanning mechanism. To address these limitations, we have developed a new generation of multiparametric PAM. Capitalizing on a self-developed high-repetition dual-wavelength pulsed laser and an optical-mechanical hybrid-scan configuration, this innovative technique has achieved an unprecedented A-line rate of 300 kHz, leading to a 20-fold increase in the imaging speed over our previously reported multiparametric PAM that is based on pure mechanical scanning. The performance of the high-speed multiparametric PAM has been examined both in vitro and in vivo. Simultaneous PAM of microvascular [Formula: see text], [Formula: see text], and CBF in absolute values over a [Formula: see text]-mm-diameter brain region of interest can be accomplished within 10 min.

Multispectral photoacoustic microscopy based on an optical-acoustic objective.

We have developed reflection-mode multispectral photoacoustic microscopy (PAM) based on a novel optical-acoustic objective that integrates a customized ultrasonic transducer and a commercial reflective microscope objective into one solid piece. This technical innovation provides zero chromatic aberration and convenient confocal alignment of the optical excitation and acoustic detection. With a wavelength-tunable optical-parametric-oscillator laser, we have demonstrated multispectral PAM over an ultrabroad spectral range of 270-1300 nm. A near-constant lateral resolution of ∼2.8 µm is achieved experimentally. Capitalizing on the consistent performance over the ultraviolet, visible, and near-infrared range, multispectral PAM enables label-free concurrent imaging of cell nucleus (DNA/RNA contrast at 270 nm), blood vessel (hemoglobin contrast at 532 nm), and sebaceous gland (lipid contrast at 1260 nm) at the same spatial scale in a living mouse ear.

Experimental demonstration of topological error correction.

Scalable quantum computing can be achieved only if quantum bits are manipulated in a fault-tolerant fashion. Topological error correction--a method that combines topological quantum computation with quantum error correction--has the highest known tolerable error rate for a local architecture. The technique makes use of cluster states with topological properties and requires only nearest-neighbour interactions. Here we report the experimental demonstration of topological error correction with an eight-photon cluster state. We show that a correlation can be protected against a single error on any quantum bit. Also, when all quantum bits are simultaneously subjected to errors with equal probability, the effective error rate can be significantly reduced. Our work demonstrates the viability of topological error correction for fault-tolerant quantum information processing.