2,5-Thiophenedicarboxylic Acid Bridging Hexameric CeIII-Substituted Selenotungstate and Its Application for Detecting Mucin 1.

The development of polyoxometalate chemistry not only is derived from the continuous discovery of novel polyoxometalates (POMs) but also stems from the exploitation of their new functionalities. In this work, we obtained a rigid sulfur-containing heterocyclic ligand-linking aggregate [N(CH3)4]10Na6H6[Ce8(H2O)26W8(HTDA)2(TDA)2O20][SeW4O18]2[SeW9O33]4·112H2O (1) (H2TDA = 2,5-thiophenedicarboxylic acid). Its polyanionic unit consists of one [Ce4(H2O)13W4O10(HTDA)(TDA)O10]18+ cluster and two kinds of Keggin-type [SeW4O18] and [SeW9O33] segments. It is noteworthy that H2TDA ligands not only work as connectors to link two symmetrical {[Ce4(H2O)13W4(HTDA)(TDA)O10][SeW4O18][SeW9O33]2}11- units but also function as ornaments to graft to the polyanionic backbone. Furthermore, 1 and 3,4-ethylenedioxythiophene (EDOT) were deposited on the glassy carbon electrode (GCE) by the electropolymerization (EPM) method, resulting in a 1-poly(3,4-ethylenedioxythiophene) (1-PEDOT) composite film, which can provide sufficient binding sites to immobilize Au nanoparticles (Au NPs). Hereafter, the Au NPs-immobilized 1-PEDOT modified electrode (Au/1-PEDOT/GCE) was used to construct an electrochemical aptasensor to detect mucin 1, showing a low detection limit of 29.5 fM in the Tris solution. This work not only demonstrates that rigid heterocyclic ligands are beneficial for the creation of novel rare-earth-substituted selenotungstate hybrids but also provides more enlightenment for POM-based materials used for electrochemical detection of cancer markers.

Multi-CeIII-Inserted Phospho(III)tungstate Containing Three Building Units with Prominent Peroxidase-Mimicking Activity for Detecting l-Cysteine.

An attractive isonicotinic acid-ornamented octa-CeIII-inserted phospho(III)tungstate [H2N(CH3)2]6Na8[Ce8(H2O)30W8Na2O20(INA)4][HPIIIW4O17]2[HPIIIW9O33]4·30H2O (1-Ce) (HINA = isonicotinic acid) has been isolated through the deliberately designed one-step assembly strategy, in which the HPO32- heteroanion template was introduced into the Ce3+/WO42- system in the presence of HINA. The polyoxoanion of 1-Ce consists of two identical [Ce4(H2O)15W4NaO10(INA)2][HPIIIW4O17][HPIIIW9O33]2}7- subunits linked by Ce-O-W bonds. The polyoxoanion exhibits three kinds of polyoxotungstate building blocks [W4NaO20(INA)2]17-, [HPIIIW4O17]6-, and [HPIIIW9O33]8-, in which [W4NaO20(INA)2]17- and [HPIIIW4O17]6- building units can be considered as seeds driven by the coordination of additional Ce3+ ions to induce aggregation of [HPIIIW9O33]8- fragments. Furthermore, 1-Ce possesses high peroxidase-like activity and can oxidize 3,3',5,5'-tetramethylbenzidine in the presence of H2O2 with a turnover rate of 6.20 × 10-3 s-1. Because l-cysteine (l-Cys) can reduce oxTMB to TMB, the detection of l-Cys was established based on the 1-Ce-based H2O2 colorimetric biosensing platform with the linear range of 5-100 µM and the limit of detection of 4.28 µM. This work not only can expand the scientific research studies on coordination chemistry and materials chemistry of rare-earth-inserted polyoxotungstates but also can provide practical application possibility in clinical diagnosis using liquid biopsy.

Two Types of Subgroup-Valence Heteroatoms (PIII, TeIV) Synergistically Controlling Octa-CeIII-Encapsulated Heteropolyoxotungstate and Its Electrochemical Recognition Properties.

Rapid development of the synthetic chemistry of polyoxometalates (POMs) has greatly driven the generation of structurally variable innovative POM-based materials. Herein, we synthesized a novel PIII and TeIV synergistically controlling octa-CeIII-encapsulated heteropolyoxotungstate [H2N(CH3)2]11K2Na6H11[Ce8(CH3COO)2(HPIIIO3)2W8O20(H2O)12(B-ß-TeW8O30)2(B-α-TeW8O31)4]·64H2O (1). Its distinctive anion skeleton [Ce8(CH3COO)2(HPIIIO3)2W8O20(H2O)12(B-ß-TeW8O30)2(B-α-TeW8O31)4]30- is built by two tetra-vacancy [B-ß-TeW8O30]8- and four tetra-vacancy [B-α-TeW8O31]10- moieties linked through an inorganic-organic hybrid [Ce8(CH3COO)2(HPIIIO3)2W8O20(H2O)12]26+ {Ce8P2W8} cluster core. Interestingly, {Ce8P2W8} is assembled from four [W2O11]10- groups and two [HPIIIO3]2- anions and eight Ce3+ ions. Besides, 1 was further composited with carboxylated multiwalled carbon nanotube (CMCN), resulting in a bi-component 1/CMCN nanocomposite. An electrochemical recognition platform (named as 1/CMCN/GCE) was built by modifying 1/CMCN on a glassy carbon electrode (GCE) for electrochemical detection of dopamine (DPA) at physiological pH (pH = 7.0). The findings have shown that 1/CMCN/GCE exhibits a good detection limit of 4.95 nM for DPA. This work provides considerable inspiration to promote innovative and rational structure designs of POM-based materials and expand their applications to electrochemical and biological detection fields.

A 1D Mixed-Valence Cuprofullerene Pyrazolate Polymer as a Semiconductor Material.

Polymeric {Cu6[(µ3-η2:η2:η2)2-C60](FPz)6Cl·3C6H5Cl}∞ [FPz = 4-(trifluoromethyl)pyrazolate], synthesized solvothermally with chlorobenzene as the solvent, is a doubly-connecting trans bis-adduct hexanuclear cuprofullerene that has copper in mixed valence. The compound is an example of a metallofullerene having semiconductivity character.

Photoelectrochemical Biosensor for MicroRNA-21 Based on High Photocurrent of TiO2/Two-Dimensional Coordination Polymer CuClx(MBA)y Photoelectrode.

Conventional photosensitive materials such as TiO2 suffer from restricted absorption in the ultraviolet region, fast recombination of photogenerated electron-hole pairs, and a lack of functional groups for biocoupling, which hinder their application in photoelectrochemical (PEC) biosensing. Herein, a new coordination polymer (CP) based on Cu(I), chloridion, and 4-mercaptobenzoic acid (MBA) has been designed and synthesized (called CuClx(MBA)y). The prepared p-type CuClx(MBA)y exhibits visible-light absorption due to its narrow optical band gap (2.59 eV), and its proper band edge position enables it to form a p-n junction with TiO2. Through layer-by-layer assembling, the photocurrent intensity of the CuClx(MBA)y/TiO2/FTO composite photoelectrode was 3.7-fold higher than that of a TiO2/FTO electrode and 35-fold higher than a CuClx(MBA)y/FTO electrode. The potential enhancement mechanism was discussed, which lies in the contributions of CuClx(MBA)y in enhancing absorption in the visible-light region and boosting the separation of electron-hole pairs of TiO2 by the p-n junction. Furthermore, CuClx(MBA)y nanosheets can realize bioconjugation directly, thanks to its abundant carboxyl groups. The CuClx(MBA)y/TiO2/FTO composite photoelectrodes were applied to develop a sensitive PEC biosensor for microRNA-21 (model target). By subtly exploiting the energy transfer between CuClx(MBA)y and Au nanoparticles (AuNPs), AuNPs served as effective quenchers. In the presence of the target, AuNP-labeled sDNA1 connected to the electrode surface, and thus, a decreased photocurrent was obtained. The proposed biosensor has a low detection limit of 0.29 fM (S/N = 3), good selectivity, and reproducibility. The proposed system was applied to monitor microRNA in cancer cells with satisfying results.

Nicotinic-Acid-Ornamented Tetrameric Rare-Earth-Substituted Phospho(III)tungstates with the Coexistence of Mixed Keggin/Dawson Building Blocks and Its Honeycomb Nanofilm for Detecting Toxins.

A fascinating class of nicotinic-acid-ornamented tetrameric rare-earth (RE)-substituted phospho(III)tungstates [NH2(CH3)2]10Na4H8[RE2(NA)(HNA)(H2O)6(W2O4)(ß-H2P2IIIW13O49)(α-HPIIIW9O33)]2·22 H2O [RE = Nd3+ (1-Nd), Tb3+ (2-Tb), Dy3+ (3-Dy), Ho3+ (4-Ho), HNA = nicotinic acid] were isolated through a one-step reaction method of Na2WO4·2H2O, H3PO3, HNA, NH2(CH3)2·HCl, and RE(NO3)·6H2O. Of meticulous concern is that HPO32- was used as a template to construct tetrameric RE-substituted phospho(III)tungstates including mixed heteropolyoxotungstate building blocks. Their hybrid polyoxoanions are composed of two symmetrical [RE2(NA)(HNA)(H2O)6(W2O4)(ß-H2P2IIIW13O49)(α-HPW9O33)]11- units linked by RE-O-W bonds. The symmetrical unit consists of one peculiar heterometal nicotinic-acid-ornamented [RE2(NA)(HNA)(W2O4)]9+ cluster connecting a pentavacant Dawson-like [ß-H2P2W13O49]12- and a trivacant Keggin [α-HPW9O33]8- subunits. Furthermore, dimethyldioctadecylammonium chloride (DMDODA·Cl) was used to combine with 1-Nd in the CHCl3-H2O system through electrostatic interactions, leading to the 1-Nd@DMDODA composite material. The honeycomb-patterned film of the 1-Nd @DMDODA composite material was successfully constructed by using the breath figure method on a glassy carbon electrode, which can offer abundant binding sites to Au nanoparticles (nano-Au). Ulteriorly, Au-functionalized 1-Nd@DMDODA-modified electrode was utilized as an electrochemical sensor to detect ochratoxin A, showing a good detection limit of 1.19 pM.

3-D Antimonotungstate Framework Based on 2,6-H2pdca-connecting Iron-Cerium Heterometallic Krebs-type Polyoxotungstates for Detecting Small Biomolecules.

An inorganic-organic hybrid 3-D FeIII-CeIII heterometallic antimonotungstate framework [Ce(H2O)5(2,6-pdca)]4H2[Fe4(H2O)6(SbW9O33)2]·38H2O (1) (2,6-H2pdca = 2,6-pyridine-dicarboxylic acid) has been synthesized via a hydrothermal method by the one-pot reaction of 2,6-H2pdca, FeCl3·6H2O, Ce(NO3)3·6H2O, and Na9[B-α-SbW9O33]·19.5H2O. Notably, the structural unit of 1 possesses a Krebs-type [Fe4(H2O)6(2,6-pdca)2(SbW9O33)2]10- subunit supported with four bridging [Ce(H2O)5(2,6-pdca)]+ moieties. It is worth highlighting that adjacent structural units are concatenated together through heterobimetallic bridges to construct a 3-D framework. Furthermore, cuboid nanocrystal 1' was prepared under mild hydrothermal conditions based on the electrostatic interaction between 1 and K+. The effects of concentration and time on the morphology of nanocrystal 1' were also studied. The cuboid nanocrystal 1' was used as a modified electrode material for simultaneous electrochemical detection of dopamine and acetaminophen. The 1'-modified glassy carbon electrode shows good selectivity and sensitivity for detecting dopamine and acetaminophen.

MicroRNA-181a exerts anti-inflammatory effects via inhibition of the ERK pathway in mice with intervertebral disc degeneration.

Enzymatic decomposition of extracellular matrix and possibly local inflammation may cause intervertebral disc degeneration (IDD). MicroRNAs have been reported to correlate with the development of IDD. In this experiment, we aim at finding out the role of miR-181a in the inflammation of IDD and the underlying mechanism. The targeting relationship between miR-181a and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was verified. Following the establishment of IDD mouse models, disc height index (DHI) and the change of DHI (%DHI) were measured. The functional role of miR-181a in IDD was determined using ectopic expression and depletion and reporter assay experiments. Expression of miR-181a, TRAIL, extracellular signal-regulated kinase (ERK) pathway-related genes and inflammatory factors was evaluated. Also, the expression of collagen I and collagen II was observed. miR-181a directly targeted TRAIL. IDD mice exhibited significant degeneration of the intervertebral disc. miR-181a was downregulated while TRAIL was upregulated in mice with IDD. miR-181a upregulation and the ERK pathway inhibition could reduce expression of TRAIL, ERK pathway-related genes, inflammatory factors, and collagen I, but promote collagen II expression. Our results reveal that upregulation of miR-181a protects against inflammatory response by inactivating the ERK pathway via suppression of TRAIL in IDD mice. These results point to miR-181a as a potential therapeutic target for the clinical management of IDD.

Synthesis of carbon quantum dots with iron and nitrogen from Passiflora edulis and their peroxidase-mimicking activity for colorimetric determination of uric acid.

Carbon quantum dots co-doped with iron and nitrogen (Fe@NCDs) were synthesized by using Passiflora edulis Sims (P. edulis) as a precursor. The Fe@NCDs exhibit outstanding peroxidase-mimetic activity owing to successful doping with iron resulting in a behavior similar to that of iron porphyrins. In the presence of H2O2, the Fe@NCDs catalyze the oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) with a color change from colorless to blue. The blue oxidation product has a characteristic absorption peaking at 652 nm. A colorimetric assay was worked out for uric acid (UA) that measures the hydrogen peroxide produced during oxidation of UA by uricase. Response is linear in the 2-150 µM UA concentration range, and the limit of detection is 0.64 µM. The method was applied to the determination of UA in (spiked) urine, and recoveries ranged from 92.0 to 103.4%. Graphical abstract Schematic representation of the fabrication of iron and nitrogen co-doped carbon dots (Fe@NCDs) using Passiflora edulis Sims as carbon-based materials. First, uric acid (UA) was oxidized to generate H2O2 by uricase. Then, the Fe@NCDs catalyzed the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to form blue-colored oxidized TMB (oxTMB) in the presence of H2O2. UA can be quantified based on the theory.

Susceptibility of methicillin-resistant Staphylococcus aureus to photodynamic antimicrobial chemotherapy with α-D-galactopyranosyl zinc phthalocyanines: in vitro study.

The incidence of methicillin-resistant strains of Staphylococcus aureus (MRSA) is increasing globally, making urgent the discovery of novel alternative therapies for infections. Photodynamic antimicrobial chemotherapy (PACT), based on oxidative damage to subcellular structures, has the advantage of circumventing multidrug resistance, and is becoming a potential therapeutic modality for methicillin-resistant bacteria. The key to PACT is photosensitization. This study demonstrates the efficiency of PACT using α-D-galactopyranosyl zinc phthalocyanines (T1-T4) for the photosensitization of MRSA, Escherichia coli, and Pseudomonas aeruginosa. Bacterial suspensions were illuminated with 650-nm light from a semiconductor laser at 0.2 W/cm(2), and the energy density was maintained at 6 J/cm(2) in the presence of different concentrations of photosensitizer. The treatment response was evaluated based on the numbers of bacterial colony-forming units. PACT with these phthalocyanines strongly affected MRSA, but weakly affected E. coli and P. aeruginosa. The efficiency of PACT on MRSA with these four phthalocyanine compounds decreased in the order T1 > T2 > T3 > T4. T1-PACT eliminated >99% of MRSA in a concentration range of 25-50 µM and at an energy density of 6 J/cm(2). Uptake measurements revealed that the PACT effect correlated with the bacterial uptake of the photosensitizer and that 4-30-fold more T1 than T2-T4 was taken up by the MRSA strain, which was confirmed with laser confocal microscopy. These data suggest that T1 is an efficient PACT photosensitizer for MRSA.

Preparation of H3PW12O40/MCM-48 and its photocatalytic degradation of pesticides.

A composite catalyst H3PW12O40/MCM-48 was prepared by loading photocatalyst phosphotungstic acid H3PW12O40 (HPW) to molecular sieve MCM-48 by impregnation method, and its structure was characterized by Fourier transform infrared (FT-IR) spectra, small angle X-ray diffraction (XRD) patterns, nitrogen adsorption analysis and High-resolution transmission electron microscopy (HRTEM) analysis. Photocatalytic degradation activities of HPW/MCM-48 against pesticides imidacloprid and paraquat were evaluated under UV radiation (365 nm). The results show that HPW/MCM-48 maintains the mesoprous molecular sieve structure of MCM-48 and the Keggin structure of HPW, while the BET surface area is 793.35 m2 x g(-1), pore volume is 1.46 cm3 x g(-1), average pore diameter is 2.76 nm, suggesting loading HPW on MCM-48 is a considerable way to improve its surface area. After 14 h UV irradiation (365 nm), 57.38% imidacloprid and 63.79% paraquat were degraded by 20 mg HPW/MCM-48 catalyst, while HPW and blank group degraded the two pesticides at the degradation rate of about 25% and 5%, respectively. Implying loading on MCM-48 could greaterly improve the degradation activity of HPW. The reslut of degradation kinetics show that, the degradation process of HPW/MCM-48 fits first order kinetics equation. The rate constant Ka of HPW/MCM-48 toward imidacloprid and paraquat are 0.089 h and 0.117 h, with the half-life t(1/2) of 7.8 h and 5.9 h, respectively.

Computer Vision-Based Biomass Estimation for Invasive Plants.

We report on the detailed steps of a method to estimate the biomass of invasive plants based on UAV remote sensing and computer vision. To collect samples from the study area, we prepared a sample square assembly to randomize the sampling points. An unmanned aerial camera system was constructed using a drone and camera to acquire continuous RGB images of the study area through automated navigation. After completing the shooting, the aboveground biomass in the sample frame was collected, and all correspondences were labeled and packaged. The sample data was processed, and the aerial images were segmented into small images of 280 x 280 pixels to create an image dataset. A deep convolutional neural network was used to map the distribution of Mikania micrantha in the study area, and its vegetation index was obtained. The organisms collected were dried, and the dry weight was recorded as the ground truth biomass. The invasive plant biomass regression model was constructed using the K-nearest neighbor regression (KNNR) by extracting the vegetation index from the sample images as an independent variable and integrating it with the ground truth biomass as a dependent variable. The results showed that it was possible to predict the biomass of invasive plants accurately. An accurate spatial distribution map of invasive plant biomass was generated by image traversal, allowing precise identification of high-risk areas affected by invasive plants. In summary, this study demonstrates the potential of combining unmanned aerial vehicle remote sensing with machine learning techniques to estimate invasive plant biomass. It contributes significantly to the research of new technologies and methods for real-time monitoring of invasive plants and provides technical support for intelligent monitoring and hazard assessment at the regional scale.

Galactose substituted zinc phthalocyanines as near infrared fluorescence probes for liver cancer imaging.

Galactose substituted with zinc phthalocyanines were synthesized and characterized as near infrared fluorescent probes. The probes have good water-solubility and high emission ability in the near infrared region. With nudemice bearing liver cancer as models, in vivo fluorescence imaging effects and organ distributions of probes show that zinc phthalocyanines with three or four galactose units have good cell biocompatibility in vitro and targeting effects for liver cancer imaging in vivo. These results show the potential of these near infrared optical probes in the diagnosis of cancer in future.

First Ultrathin Pure Polyoxometalate 2D Material as a Peroxidase-Mimicking Catalyst for Detecting Oxidative Stress Biomarkers.

Although two-dimensional (2D) materials with ultrathin geometry and extraordinary electrical attributes have attracted substantial concern, exploiting new-type 2D materials is still a great challenge. In this work, an unprecedented single-layer pure polyoxometalate (POM) 2D material (2D-1) was prepared by ultrasonically exfoliating a one-dimensional (1D)-chain heterometallic crystalline germanotungstate Na4[Ho(H2O)6]2[Fe4(H2O)2(pic)6Ge2W20O72]·16H2O (1) (Hpic = picolinic acid). The 1D polymeric chain of 1 is assembled from particular {Ge2W20}-based [Fe4(H2O)2(pic)6Ge2W20O72]10- segments through bridging [Ho(H2O)6]3+ cations. 2D-1 is formed by π-π interaction driving force among adjacent 1D polymeric chains of 1. Also, the peroxidase-mimicking properties of 2D-1 toward detecting H2O2 were evaluated and good detection result was observed with a limit of detection (LOD) of 58 nM. Density functional theory (DFT) calculation further confirms that 2D-1 displays outstanding catalytic activity and active sites are located on Fe centers and Hpic ligands. Under the catalysis of uricase, uric acid can be transformed to allantoin and H2O2, and then, H2O2 oxidizes TMB to its blue ox-TMB in the presence of 2D-1 as a catalyst. Then, we utilized this cascade reaction to detect uric acid, which also exhibits prominent results. This research opens a door to prepare ultrathin pure POM 2D materials and broadens the scope of potential applications of POMs in biology and iatrology.

[Preparation, characterization and photocatalytic activities of polyoxometalates immobilized on mesoporous moleculer sieve].

Heterogeneous photocatalysts consisting of phosphotungstic acid or silicotungstic acid immolilized on mesoporous molecular sieve MCM-41 were prepared and characterized by FTIR, X-ray diffraction, nitrogen adsorption and high resolution transmission electron microscope (HRTEM). The photocatalytic activities of the prepared H3PW12 O40/MCM-41 or H4SiW12O40/MCM-41 were examined by photodegradation of pesticide paraquat. Results show that the prepared composites have large specific surface area and uniform mesopores, the Keggin structure of two parent heteropoly acids was retained after loading on MCM-41. Both of the prepared photocatalysts exhibit high activityies under irradiation of 365 nm monochromatic Light. For 50 mL paraquat (10 mg x L(-1)), conversions of paraquat using 15 mg H3PW12O40/MCM-41 or H4SiW12O40/MCM-41 as catalysts after 14 hours' irradiation are 92.0% and 87.6% respectively. The photocatalytic reactions are in accordance with the first order kinetics equation, and the half lives of the reactions are 3.6 h and 4.7 h respectively.

Integral sliding mode consensus of networked control systems with bounded disturbances.

This article addresses the consensus tracking problem of networked control systems with disturbances. The network topology is directed, and only partial followers can exchange information with the leader. In the light of the continuous consensus law for the nominal network control systems, a discontinuous integral sliding mode protocol is designed to ensure that networked control systems with bounded disturbances achieve the consensus in a setting time. Furthermore, this article also solve the problem that the sliding function chattering and the control gains are difficult to determine in discontinuous consistency protocol. The continuous integral sliding mode consensus protocol is proposed. It is pointed out that the advantage of adaptive control method is that it can automatically adjust the controller gain, and may ensure the control protocol execute well without prior knowledge of networked control systems. In the end, simulation results illustrate that the efficacy of this new approach is validated.

Formation control of nonholonomic unmanned ground vehicles via unscented Kalman filter-based sensor fusion approach.

This paper investigates the formation control of nonholonomic unmanned ground vehicles via unscented Kalman filter-based sensor fusion approach. According to the kinematic model of single unmanned ground vehicle, the formation model of multiple unmanned ground vehicles is established. Note that the physical leader is considered instead of a virtual leader, which is more realistic. The formation control problem is converted to the stability problem of an error dynamic system. An asymptotic stability condition of the error dynamic system is derived by designing an appropriate Lyapunov function. The leader-following formation is well formed through designing effective control vectors and utilizing unscented Kalman filter-based state estimation algorithm for each follower. Some simulation examples are provided to verify the effectiveness of the proposed formation control algorithm.

Lamellar Nanocomposite Based on a 1D Crayfish-like CeIII-Substituted Phospho(III)tungstate Semiconductor and Polyaniline Used as a High-Performance Humidity Sensing Device.

In order to meet people's demand for intelligent management of daily life and health, manufacturing and developing humidity monitoring equipment with convenience, high sensitivity, easy miniaturization, and low cost is particularly important in the era of rapid development of artificial intelligence and the Internet of Things. Polyaniline (PANI) is an attractive humidity sensing material due to its designable functional properties. However, PANI modified polyoxometalates (POMs) for humidity sensing are still rare. As a proof of concept, a novel moisture sensing composite material was obtained based on PANI and a novel 1D rare-earth-substituted phospho(III)tungstate [H2N(CH3)2]9Na3H6[Ce2(H2O)3W5O13(C2O4)][HPIIIW9O33]2[(HPIII)2W15O54]·42H2O (1). Notably, the anion structure of 1 contains trivacant Keggin-type [B-α-HPIIIW9O33]8- and Dawson-like [(HPIII)2W15O54]10- subunits linked by a heterometallic [Ce2(H2O)3W5O32(C2O4)]30- cluster. Furthermore, the 1/PANI composite shows a typical semiconductive characteristic with a "band-like" conductive mechanism. The fabricated 1/PANI-based humidity sensing device exhibits a broad sensing range (11∼97% relative humidity), fast response/recovery time (3.45 s/3.24 s), good repeatability, and long-term stability (over 3 months). Additionally, the possible sensing mechanism is proposed. This work offers an enormous possibility for the design of high-performance humidity sensing materials through POM material chemistry.

Robust Lidar-Based Localization Scheme for Unmanned Ground Vehicle via Multisensor Fusion.

This article proposes a robust and precise localization scheme for unmanned ground vehicle (UGV) in global positioning system (GPS)-denied and GPS-challenged environments via multisensor fusion approach. The localization scheme is proposed to be under an available point-cloud map. First, initialization in localization module is designed to calculate the initial position of UGV in map using the Gaussian projection approach and obtain the frame transformation between the 3-D lidar and the inertial measurement unit (IMU). Second, the best alignment between each scan frame and the available submap is obtained, and the pose of vehicle relative to the origin of map is calculated. Third, the precise pose of UGV is well predicted by integrating the data from 3-D lidar and IMU. Fourth, in order to visually verify the proposed localization scheme, the motion of vehicle is visualized by designing the visualization module. Note that the preprocessing module aims to process the raw scan data. The availability of our proposed localization scheme is verified by conducting experiments in our campus.

Applications of UAS in Crop Biomass Monitoring: A Review.

Biomass is an important indicator for evaluating crops. The rapid, accurate and nondestructive monitoring of biomass is the key to smart agriculture and precision agriculture. Traditional detection methods are based on destructive measurements. Although satellite remote sensing, manned airborne equipment, and vehicle-mounted equipment can nondestructively collect measurements, they are limited by low accuracy, poor flexibility, and high cost. As nondestructive remote sensing equipment with high precision, high flexibility, and low-cost, unmanned aerial systems (UAS) have been widely used to monitor crop biomass. In this review, UAS platforms and sensors, biomass indices, and data analysis methods are presented. The improvements of UAS in monitoring crop biomass in recent years are introduced, and multisensor fusion, multi-index fusion, the consideration of features not directly related to monitoring biomass, the adoption of advanced algorithms and the use of low-cost sensors are reviewed to highlight the potential for monitoring crop biomass with UAS. Considering the progress made to solve this type of problem, we also suggest some directions for future research. Furthermore, it is expected that the challenge of UAS promotion will be overcome in the future, which is conducive to the realization of smart agriculture and precision agriculture.