Search

A multicolor fluorescent nanoprobe has been prepared by loading bovine serum albumin-stabilized copper nanoclusters (BSA-Cu NCs) onto amino clay (AC) and grafting Eu

Using pure Ti and hexagonal-BN powder as raw materials, TiB2–TiN ceramic composites were synthesized by high-pressure method at 5.0 GPa and 1400–1800 °C. The phase composition, microstructure, density and hardness of TiB2–TiN ceramic composites were analyzed. The results shown that when the pressure was constant, the synthesis temperature had an important effect on the phase composition of the samples. When TiB2–TiN ceramic composites synthesized at 1800 °C for 30 min, the relative density reached 96.2% and the maximum Vickers hardness reached 17.9 GPa with the load of 4.9 N. The grain size of the TiB2–TiN ceramic composites changed with the change of synthesis temperature, which resulted in the change of density and hardness.

A novel multicolor fluorescent nano-probe based on the hybridization of Tb

In this paper, we provide a necessary condition and a sufficient condition such that any [Formula: see text]-sparse vector [Formula: see text] can be recovered from [Formula: see text] via [Formula: see text] local minimization. Moreover, we further verify that the sufficient condition is naturally valid when the restricted isometry constant of the measurement matrix [Formula: see text] satisfies [Formula: see text]. Compared with the existing [Formula: see text] local recoverability condition [Formula: see text], this result shows that [Formula: see text] local recoverability contains more measurement matrices.

To reveal the effect and mechanism of Jiaotai Pill (交泰丸, JTP) on insomniac rats. The insomniac model was established by intraperitoneal injection of p-chlorophenylalanine (PCPA). In behavioral experiments, rats were divided into control, insomniac model, JTP [3.3 g/(kg•d)], and diazepam [4 mg/(kg•d)] groups. The treatment effect of JTP was evaluated by weight measurement (increasement of body weight), open field test (number of crossings) and forced swimming test (immobility time). A high performance liquid chromatography-electrochemical detection (HPLC-ECD) method was built to determine the concentration of monoamine transmitters in hypothalamus and peripheral organs from normal, model, JTP, citalopram [30 mg/(kg•d)], maprotiline [40 mg/(kg•d)] and bupropion [40 mg/(kg•d)] groups. Expressions of serotonin transporter (SERT), dopamine transporter (DAT), and norepinephrine transporter (NET) were analyzed by quantitative polymerase chain reaction (qPCR) and Western blot in normal, model and JTP groups. A high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS/MS) method was established to determine the pharmacokinetics, urine cumulative excretion of metformin in vivo, and tissue slice uptake in vitro, which were applied to assess the activity of organic cation transporters (OCTs) in hypothalamus and peripheral organs. Compared with the insomniac model group, the body weight and spontaneous locomotor were increased, and the immobility time was decreased after treatment with JTP (P

Saccadic eye movement as a voluntary activity has become the basis of a promising approach for the implementation of human–computer interaction. Seeking blind source separation (BSS) model that can exactly describe eye movement generation and improve the quality of saccadic electrooculography (EOG) signals, we performed a comparative study between an instantaneous and a convolutional mixing model for multichannel EOG signals. Experiments involving seven subjects were carried out in a laboratory environment. The independent component analysis (ICA) method was adopted for BSS. The statistical indicators of the residual statistical dependence and the total square cross correlation for the convolutional model were 0.04 (second order)/0.08 (fourth order) and 1.25, respectively, which were lower than those of the instantaneous model by 0.3 (second order)/0.17 (fourth order) and 0.32, respectively. In addition, the average classification accuracies of the convolutional model were 95.76% (within subject) and 94.08% (between subject) in the case of upward, downward, left, and right saccade tasks, which were higher than those of the instantaneous model by 1.69% and 5.53%, respectively. Experiments revealed that the quality of the saccadic signals separated using the convolutional model was higher than that achieved using the instantaneous model. The outcomes of this research can serve as a valuable reference for multichannel EOG analysis and application.

Most face relighting methods are able to handle diffuse shadows, but struggle to handle hard shadows, such as those cast by the nose. Methods that propose techniques for handling hard shadows often do not produce geometrically consistent shadows since they do not directly leverage the estimated face geometry while synthesizing them. We propose a novel differentiable algorithm for synthesizing hard shadows based on ray tracing, which we incorporate into training our face relighting model. Our proposed algorithm directly utilizes the estimated face geometry to synthesize geometrically consistent hard shadows. We demonstrate through quantitative and qualitative experiments on Multi-PIE and FFHQ that our method produces more geometrically consistent shadows than previous face relighting methods while also achieving state-of-the-art face relighting performance under directional lighting. In addition, we demonstrate that our differentiable hard shadow modeling improves the quality of the estimated face geometry over diffuse shading models., Comment: Accepted to CVPR 2022

Valued for its toughness and durability, Kaihua paper has been famous in China since the Qing Dynasty and is in the focus of the study on paper life extension. Understanding of the complex degradation behavior of handmade paper under various aging conditions is an essential precondition for preparing contemporary long-life handmade paper. However, reactions sequence and quantitative analysis of microstructure of cellulose and its relation to macroscopic deterioration of handmade paper still are difficult to interpret. Herein, different types of Kaihua handmade papers, produced by various raw materials and crafts, were artificially aged to study the different evolution of their multi-scale structures in dry-heat (DH) and wet-heat (WH) conditions systematically. Two-dimensional correlation spectroscopy (2D-COS) distinguished possible carbonyl vibrations involving hydrolysis and oxidation of cellulose and gave sequential changes of various carbonyl groups, illustrating different evolution behaviors of molecular structure of papers in DH and WH aging process. The energy and distance of hydrogen bond, crystal size and microfiber accessibility were quantitatively calculated during the degradation of cellulose. The dual roles of water molecules, as plasticizers for fibers and as carriers of protons, continuously promoting the hydrolysis of cellulose at molecular and supramolecular scales were elucidated further. In addition, correlations between microstructural evolution and macroscopic deterioration of handmade papers involving reduced mechanical properties and yellowing were revealed.

To address the variabilities of the number and position of extracted feature points for the traditional scale-invariant feature transform (SIFT) method, an improved SIFT algorithm is proposed for robust emotion recognition. Specifically, shape decomposition is first performed on the detected facial images by defining a weight vector. Then, a feature point constraint algorithm is developed to determine the optimum position of the feature points that can effectively represent the expression change regions. On this basis, the SIFT descriptors are applied to extract the regional gradient information as feature parameters. Finally, the support vector machine classifier combined with the principal component analysis method is used to reduce the feature dimensions and facial expression recognition. Experiments have been performed under different conditions, i.e., varied illuminations, face poses and facial moisture levels, using 15 participants. In the cases of frontal face and 5-degree face rotation views, the average recognition accuracies are 98.52% and 94.47% (no additional light sources), as well as 96.97% and 95.40% (two additional light sources), respectively. In addition, as an effective supplement to the problem of changes in illumination, the average recognition ratios are 96.23% and 96.20% under dry and wet face conditions, respectively. The experimental results reveal the robust performance of the proposed method in facial expression recognition.

Dense TiB2 TiC composites were synthesized by high pressure method at 5.5 GPa and 1400–1800 °C with pure Ti and B4C powders as raw materials. The phase composition, density, microstructure, hardness and thermal conductivity of TiB2 TiC composites were analyzed. The results indicated that, the formation of intermediate phases were strongly depended on the synthesis temperature. TiB2 TiC composites prepared under high pressure condition had a dense microstructure without obvious pores, which could achieve the bulk density and the relative density about 4.40–4.57 g/cm3 and 95.1%–98.7%. Vickers hardness values was up to 22.1–30.1 GPa with the load of 4.9 N and 20.3–28.9 GPa with the load of 9.8 N. Thermal conductivity of the TiB2 TiC composites was measured to be 51.2–74.5 W/m−1 K−1. The density and grain size of the TiB2 TiC composites changed with the increase of temperature, leading to the change of hardness and thermal conductivity.

This paper presents a new flexible approach to predict the gender of the writers from their handwriting samples. Handwriting features like slant, curvature, line separation, chain code, character shapes, and more, can be extracted from different methods. Therefore, the multi-feature sets are irrelevant and redundant. The conflict of the features exists in the sets, which affects the accuracy of classification and the computing cost. This paper proposes an approach, named kernel mutual information (KMI), that focuses on feature selection. The KMI approach can decrease redundancies and conflicts. In addition, it extracts an optimal subset of features from the writing samples produced by male and female writers. To ensure that KMI can apply the various features, this paper describes the handwriting segmentation and handwritten text recognition technology used. The classification is carried out using a Support Vector Machine (SVM) on two databases. The first database comes from the ICDAR 2013 competition on gender prediction, which provides the samples in both Arabic and English. The other database contains the Registration-Document-Form (RDF) database in Chinese. The proposed and compared methods were evaluated on both databases. Results from the methods highlight the importance of feature selection for gender prediction from handwriting.

Existing face relighting methods often struggle with two problems: maintaining the local facial details of the subject and accurately removing and synthesizing shadows in the relit image, especially hard shadows. We propose a novel deep face relighting method that addresses both problems. Our method learns to predict the ratio (quotient) image between a source image and the target image with the desired lighting, allowing us to relight the image while maintaining the local facial details. During training, our model also learns to accurately modify shadows by using estimated shadow masks to emphasize on the high-contrast shadow borders. Furthermore, we introduce a method to use the shadow mask to estimate the ambient light intensity in an image, and are thus able to leverage multiple datasets during training with different global lighting intensities. With quantitative and qualitative evaluations on the Multi-PIE and FFHQ datasets, we demonstrate that our proposed method faithfully maintains the local facial details of the subject and can accurately handle hard shadows while achieving state-of-the-art face relighting performance., Accepted to CVPR 2021

A simple and rapid colorimetric assay for determination of mercury(II) ion (Hg2+) in aqueous solutions was developed based on aggregation of gold/silver alloy nanocomposites (Au/Ag NCs). Au/Ag NCs were aggregated after the addition of Hg2+ and the positively charged amino acid, lysine. The different aggregation degrees of Au/Ag NCs is indicated by variations in the absorption spectra and accompanied by a color change from orange yellow to yellowish green. Under the optimal conditions, the shift of absorbance ratio (A650/A447) was proportional to Hg2+ concentrations in the range of 0.01–10.0 μM. The limit of detection is 4.8 nM. The proposed colorimetric assay was extremely specific for Hg2+ and other environmentally relevant metal ions did not interfere with the determination.

Recent progresses in visual tracking have greatly improved the tracking performance. However, challenges such as occlusion and view change remain obstacles in real world deployment. A natural solution to these challenges is to use multiple cameras with multiview inputs, though existing systems are mostly limited to specific targets ( e.g. human), static cameras, and/or require camera calibration. To break through these limitations, we propose a generic multiview tracking (GMT) framework that allows camera movement, while requiring neither specific object model nor camera calibration. A key innovation in our framework is a cross-camera trajectory prediction network (TPN), which implicitly and dynamically encodes camera geometric relations, and hence addresses missing target issues such as occlusion. Moreover, during tracking, we assemble information across different cameras to dynamically update a novel collaborative correlation filter (CCF), which is shared among cameras to achieve robustness against view change. The two components are integrated into a correlation filter tracking framework, where features are trained offline using existing single view tracking datasets. For evaluation, we first contribute a new generic multiview tracking dataset (GMTD) with careful annotations, and then run experiments on the GMTD and CAMPUS datasets. The proposed GMT algorithm shows clear advantages in terms of robustness over state-of-the-art ones.

To reveal the effect and mechanism of Jiaotai Pill (, JTP) on insomniac rats.The insomniac model was established by intraperitoneal injection of p-chlorophenylalanine (PCPA). In behavioral experiments, rats were divided into control, insomniac model, JTP [3.3 g/(kg•d)], and diazepam [4 mg/(kg•d)] groups. The treatment effect of JTP was evaluated by weight measurement (increasement of body weight), open field test (number of crossings) and forced swimming test (immobility time). A high performance liquid chromatography-electrochemical detection (HPLC-ECD) method was built to determine the concentration of monoamine transmitters in hypothalamus and peripheral organs from normal, model, JTP, citalopram [30 mg/(kg•d)], maprotiline [40 mg/(kg•d)] and bupropion [40 mg/(kg•d)] groups. Expressions of serotonin transporter (SERT), dopamine transporter (DAT), and norepinephrine transporter (NET) were analyzed by quantitative polymerase chain reaction (qPCR) and Western blot in normal, model and JTP groups. A high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS/MS) method was established to determine the pharmacokinetics, urine cumulative excretion of metformin in vivo, and tissue slice uptake in vitro, which were applied to assess the activity of organic cation transporters (OCTs) in hypothalamus and peripheral organs.Compared with the insomniac model group, the body weight and spontaneous locomotor were increased, and the immobility time was decreased after treatment with JTP (P0.01). Both serotonin and dopamine contents in hypothalamus and peripheral organs were increased (P0.01). The norepinephrine content was increased in peripheral organs and decreased in hypothalamus (P0.05 or P0.01). At the same time, SERT, DAT, OCT1, OCT2, and OCT3 were down-regulated in hypothalamus and peripheral organs (P0.05). NET was down-regulated in peripheral organs and up-regulated in hypothalamus (P0.05 or P0.01). Moreover, the activity of OCTs in hypothalamus and peripheral organs was inhibited (P0.05).JTP alleviates insomnia through regulation of monoaminergic system and OCTs in hypothalamus and peripheral organs.

To explore the pathogenesis of heart and kidney imbalance insomnia and the regulatory effect of Jiaotai Pills, in order to study the changes of central and peripheral neurotransmitters in rat. Insomnia rats with heart and kidney imbalance were induced through intraperitoneal injection with p-chlorophenylalanine(PCPA, 400 mg·kg~(-1)·d~(-1)), and the model rats were intragastrically administrated with Jiaotai Pills(3.3 g·kg~(-1)·d~(-1)) for 7 days. Nine neurotransmitters were determined by UPLC-MS/MS and principal component analysis(PCA) method in serum, urine, brain, heart, liver, kidney and adrenal gland of rats. The results showed that the ratio of 5-HT and 5-HIAA in platelet of insomnia rats was significantly lower than that in the normal group, and Jiaotai Pills had a significant up-regulatory or down-regulatory effect. Compared with the normal group, the changed neurotransmitters in blood of insomnia rats were 5-HIAA, E, NE, DA, Glu and ACH, and except ACH, the changes of 7 kinds of neurotransmitters in urine were more significant, Jiaotai Pills had a significant up-regulatory or down-regulatory effect. Compared with the normal group, all of the 8 neurotransmitters in insomnia rats except HVA were changed. Jiaotai Pills could regulate the neurotransmitters in each tissue of insomnia rats, especially in brain, liver and adrenal gland. In conclusion, insomnia is caused by not only a change of neurotransmitters in brain, but also a series of changes in peripheral tissues. It indicates that insomnia is a systematic imbalance of neurotransmitters. Jiaotai Pills not only regulates the central nervous system, but also has a certain protective effect on other organs, reflecting the multi-target and systematic effect of Jiaotai Pills in the treatment of insomnia.

The metal-organic frameworks (MOFs) functionalized palygorskite (Pal) hybrid as a novel multicolor fluorescence probe for the detection of bacterial spore biomarker-dipicolinic acid (DPA), had been prepared via in-situ growth. The MOFs can effectively encapsulate dye molecules on the surface of Pal, and the rich carboxyl groups on its surface can coordinate with europium ions (Eu3+), forming a highly sensitive recognition group. The results indicated that the limit of detection (LOD) of this multicolor fluorescence probe was as low as 9.3 nM and was obviously lower than the amount of anthrax spores infecting the human body (60 μM). Moreover, a wide linear range from 0 to 35 μM was obtained. The high specific surface area of Pal, as well as the permanent porosity and suitable binding sites of Eu3+-doped MOFs may play a major role in the sensitivity and linear detection range. The multicolor fluorescence strategy made full use of the diversity of fluorescence signals collected by dye molecules and lanthanide ions, which can realize the real-time and on-site detection through the smartphone with a color-scanning application (APP). The practicability of this probe was further verified by detecting DPA released by non-infectious Bacillus subtilis.

The sensitive, selective and point-of-care detection of dipicolinic acid (DPA) is of great significance for the prevention of the anthrax virus and the containment of bioterrorism. In this work, a multi-color fluorescent nanoprobe composed of lanthanides and magnetic nanoparticles (Fe3O4@CePO4:Tb-EDTA-Eu) has been designed, in which the portion of Fe3O4@CePO4:Tb can be used as the internal stable signal of green fluorescence, while the EDTA-Eu part can be used as the sensitive reaction signal for monitoring DPA. Upon the addition of DPA, the red fluorescence of Eu3+ ions is significantly enhanced, while the fluorescent color of the nanoprobes can change from green to red (such as yellow-green, orange-yellow and orange-red), achieving visual multi-color fluorescent detection even by the naked eye. By using the magnetic separation method, the composites can be easily purified for point-of-care testing. More importantly, the nanoprobe fixed test pieces enable real-time analysis of DPA by using an easy-to-access color-scanning application on a smartphone. Furthermore, the fluorescence intensity can be quenched by the addition of Cu2+, which leads to a rewritable nanosensor and can be used in the detection of cysteine (Cys) with high sensitivity. With the addition of Cys, this erasable nano detection platform can also display the original multi-color visual point-of-care detection. With further optimization, this new type of multi-color fluorescent assay is promising in point-of-care clinics for multi-target diagnostics.

Mathematical expression recognition has been one of the most fascinating research among the various researches in field of image processing. This problem typically consists of three major stages, namely, expression positioning, symbol segmentation, symbol recognition, and structural analysis. In this paper, we will review most of the existing work with respect to each of the major stages of the recognition process. Moreover, some important issues in mathematical expression recognition, like handwritten MEs, will be addressed in depth. Finally, point out the future research directions of mathematical expression.

We propose a novel real-time selfie video stabilization method. Our method is completely automatic and runs at 26 fps. We use a 1D linear convolutional network to directly infer the rigid moving least squares warping which implicitly balances between the global rigidity and local flexibility. Our network structure is specifically designed to stabilize the background and foreground at the same time, while providing optional control of stabilization focus (relative importance of foreground vs. background) to the users. To train our network, we collect a selfie video dataset with 1005 videos, which is significantly larger than previous selfie video datasets. We also propose a grid approximation to the rigid moving least squares that enables the real-time frame warping. Our method is fully automatic and produces visually and quantitatively better results than previous real-time general video stabilization methods. Compared to previous offline selfie video methods, our approach produces comparable quality with a speed improvement of orders of magnitude. Our code and selfie video dataset is available at https://github.com/jiy173/selfievideostabilization.

Valued for its toughness and durability, Kaihua paper has been famous in China since the Qing Dynasty. It attracts great attention on the extension of paper life. Understanding of the complex degradation behavior of handmade paper under various aging conditions is an essential precondition for preparing long-life handmade paper. However, it is still difficult to explain the reactions sequence of cellulose microstructure and its relationship with the macroscopic deterioration of handmade paper. Herein, different types of Kaihua handmade papers, produced by various raw materials and crafts, were artificially aged. The evolution of their multi-scale structures in dry-heat (DH) and wet-heat (WH) conditions was explored systematically. Two-dimensional correlation spectroscopy (2D-COS) distinguished possible carbonyl vibrations involving hydrolysis and oxidation of cellulose and gave sequential changes of various carbonyl groups, illustrating different evolutionary behaviors of molecular structure of papers in DH and WH aging process. The energy and distance of hydrogen bond, crystal size and microfiber accessibility were quantitatively calculated during the degradation of cellulose. In addition, correlations between microstructural evolution and macroscopic deterioration of handmade papers involving reduced mechanical properties and yellowing were revealed. The current results will help to establish a platform for the multi-scale detection of handmade paper and improve the understanding of the degradation mechanism of handmade paper under different reaction paths. It also provides useful foundation on the preparation of long-life paper and the conservation of paper-based culture relics.

It is of vital significance to achieve accurate real-time detection of tetracycline (TC). In this research, the ratio fluorescence detection of tetracycline is realized by introducing europium-based aminoclay containing carbon dots with good sensitivity to tetracycline through subsequent surface modification. With the increase of tetracycline concentration, the fluorescence intensity of rare earth europium fluorophore increases continuously, while the fluorescence intensity of CDs is basically unchanged. The CIE chromaticity coordinate confirms that the luminous color of the probe can be adjusted continuously from blue to red. The results exhibit this approach owns the favourable linearity to TC within 0∼12.5 μM and 10∼25 μM, and the high sensitivity with a low detection limit of 3.133 nM. Moreover, it can entirely satisfy the requirements of field detection because the rapid monitoring time as short as 30 s. The multicolor fluorescence detection strategy is reliable and feasible in the field test of TC in various actual samples. In addition, a TC floating detector based on vertical float structure is designed to achieve the rapid visual detection of TC in simulated flow environment. The superiority of the sensing platform opens up a neo-pathway for point-of-care monitoring of TC residues.

Ultra performance liquid chromatography-tandem mass spectrometry( UPLC-MS/MS) was used to establish the simultaneous determination method of eight neurotransmitters in brain,liver,kidney,adrenal gland,serum and urine,including serotonin,5-hydroxyindole acetic acid,epinephrine,norepinephrine,dopamine,glutamic acid,γ-aminobutyric acid,and acetylcholine,and then investigate the distribution characteristics of neurotransmitters in rat tissues,blood and urine. Waters ACQUITY UPLC BEH C_(18) column( 2. 1 mm×100 mm,1. 7 μm) was used,with 0. 3% formic acid solution-acetonitrile as the mobile phase for gradient elution.Multiple reaction monitoring( MRM) scanning method under positive mode by atmospheric pressure electrospray ion source( ESI) was also performed to establish the detection method of neurotransmitters for methodological research. The plasma,urine and tissues of normal rats were pre-treated including homogenization,centrifuging,and protein removal,then the 2 μL supernatant was injected for analysis. The results showed that eight kinds of neurotransmitters could be accurately determined within 7 min,with linear correlation coefficients all greater than 0. 99. This method showed high accuracy and good precision,with specificity,stability,extraction recovery and matrix effects all complying with the biological sample analysis requirements. The most abundant transmitters in the brain,liver,kidney,kidney gland,blood and urine were γ-aminobutyric acid,glutamic acid,glutamic acid,adrenaline,glutamic acid and dopamine.The method is sensitive,rapid,precise,accurate and specific,and can be used for simultaneous quantitative analysis of eight neurotransmitters in biological samples. The investigation of the distribution ratio of transmitters in rats is of important significance to disease prevention and treatment.

Since the 2001 anthrax attacks, researchers have focused on the development of a bacterial spore biomarker detector with rapid response time and high sensitivity and selectivity. Hence, a ratiometric fluorescent nanosensor based on lanthanide-functionalized attapulgite (Atta) was designed and prepared using dye-doped Atta as an internal reference. Atta, which is famous because of Maya Blue, is a hydrated magnesium aluminum silicate present in nature, with pronounced adsorption and a large specific surface area rich in silicon hydroxyl. The adsorption of dye molecules benefits the formation of an internal reference with orange fluorescence. Meanwhile, silicon hydroxyl would be available for terbium (Tb 3+ ) complex grafting, which favors the sensitization of the bacterial spore biomarker. With increasing dipicolinic acid (DPA) concentrations, energy transfer from DPA to Tb 3+ gradually enhanced, thereby resulting in strong and predominant green fluorescence. The ratiometric fluorescence intensity is highly sensitive. It has a limit of detection of 9.8 nM, which is much lower than the infectious dosage of Bacillus anthracis spores (60 μM) for humans. The rapid response time (10s), high selectivity, and reliable and practical performances in actual applications make this ratiometric fluorescent nanosensor useful in the detection of biomarkers for various bacterial spores. Moreover, the reported construction of visual ratiometric detection system follows the sustainable development idea of ‘‘from nature, for nature, into the nature’’ and promotes the use of naturally renewable resources to produce promising and eco-friendly functional materials for various applications.