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Multilayer ceramic actuators find extensive utility in applications requiring precise displacement control or force output, due to their advantages of high precision control, rapid response, low driving voltage, low power consumption, and so on. For practical applications, there is a need for high‐performance multilayer ceramic actuators (MLAs) that combine cost‐effectiveness, efficiency, and temperature stability. In this work, 1.5 mol%Sm‐doped 0.25 Pb(Mg1/3Nb2/3)O3–0.36PbZrO3–0.39PbTiO3 piezoelectric ceramics with PbO–CuO as sintering aid were fabricated. The addition of PbO–CuO significantly reduced the sintering temperature by 300°C, while having minimal impact on the piezoelectric properties. The optimized sintering condition, achieved at a low sintering temperature of 950°C with the introduction of a tiny 0.4 wt% sintering aid, yields impressive piezoelectric strain coefficient d33* = 690 pm/V. This substantiates the viability of employing low‐cost Ag/Pd (90/10) as inner electrode, which can be co‐fired with ceramic layer to fabricate MLA. This innovation enables a remarkable displacement of 1 µm at a low driving voltage of 200 V across a 9‐layers piezoelectric actuator, accompanied by high‐temperature stability, exhibiting <20% variation over the temperature range of 30–250°C. These results underscore a great potential for high‐performance piezoelectric actuators over a broad temperature range. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramics with high strain response and low hysteresis are highly in demand for high-performance actuator applications. Unfortunately, the trade-off relationship between large field-induced strain and low hysteresis in piezoelectric ceramics is a key challenge for designing high-performance piezoelectric actuators. Herein, y mol%La-doped 0.10 Pb(In 1/2 Nb 1/2)O 3 - x PbZrO 3 -(0.90 – x)PbTiO 3 [0.10PIN- x PZ-(0.90-x)PT: y mol%La] ternary relaxor ferroelectric ceramics were prepared by conventional solid-state reaction technique. Pb(In 1/2 Nb 1/2)O 3 (PIN) as a relaxor end member was introduced into (Pb,La) (Zr,Ti)O 3 (PLZT) system to improve relaxor characteristics and strain properties. A giant strain of 0.23% was obtained in 0.10PIN-0.59PZ-0.31 PT: 8mol%La ceramic at the electric field of 20 kV/cm, with a high piezoelectric d 33 * of 1150 pm/V and low hysteresis H y of 6.4%, exhibiting a potential application in high-performance piezoelectric actuators. Furthermore, the effects of La ion doping and components on the ferroelectric, dielectric and electric field-induced strain properties were investigated, and provides a new way for improve the strain properties of piezoelectric materials. [ABSTRACT FROM AUTHOR]

The development of ferroelectric ceramics with both large piezoelectric responses and broad service temperature range is still a key challenge for practical applications due to the so-called d 33 - T C trade-off. Here we report the strategy to utilize the synergistic contribution of morphotropic phase boundary and enhanced local structural heterogeneity, in which an excellent piezoelectric coefficient d 33 of 680 pC/N and a high Curie temperature of 330 ℃ are simultaneously achieved in Sm modified 0.25PIN-0.325PZ-0.425PT ceramics. The underlying mechanism responsible for the high dielectric and piezoelectric properties is studied based on cryogenic dielectric measurement and Rayleigh analysis. Of particular interest is that, a high field-induced strain of 0.19% is achieved in 0.25PIN-0.32PZ-0.43PT at electric field of 20 kV/cm, corresponding to a piezoelectric d 33 * of 945 pm/V, showing an excellent temperature stability with minimal variation of 7% up to 310 °C. This work demonstrates the introduction of high temperature end members and rare earth doping are conducive to ferroelectric solid solutions with desired broad usage temperature range and superior piezoelectric properties, which will greatly benefit high temperature actuator applications. [ABSTRACT FROM AUTHOR]

There is a great demand to develop ferroelectric ceramics with both high piezoelectric coefficient and broad temperature usage range for emerging electromechanical applications. Herein, a series of Sm3+‐doped 0.25Pb(Mg1/3Nb2/3)O3‐(0.75−x)PbZrO3‐xPbTiO3 ceramics were fabricated by solid‐state reaction method. The phase structure, dielectric and piezoelectric properties were investigated, where the optimum piezoelectric coefficient d33 = 745 pC/N and electromechanical coupling factor k33 = 0.79 were obtained at the morphotropic phase boundary composition x = 0.39, with good Curie temperature TC of 242°C. Of particular importance is that high‐temperature stability of the piezoelectric and field‐induced strain was obtained over the temperature range up to 230°C for the tetragonal compositions of x = 0.40. The underlying mechanism responsible for the high piezoelectricity and temperature stability is the synergistic contribution of the MPB and local structural heterogeneity, providing a good paradigm for the design of high‐performance piezoelectric materials to meet the challenge of piezoelectric applications at elevated temperature. [ABSTRACT FROM AUTHOR]

Circular RNA (circRNA) can modulate the gene expression via sponging microRNA (miRNA) in multiple malignancies. Nevertheless, the detailed function of circ_0001658 in osteosarcoma (OS) and its regulatory mechanism remain elusive. Real‐time PCR was carried out to detect the expressions of circ_0001658, miR‐382‐5p, and Y box‐binding protein 1 (YB‐1) mRNA in OS tissues. Besides, western blot was done to monitor YB‐1 expression in OS cells. Chi‐squared test was used to analyse the correlation between circ_0001658 and clinicopathologic characteristics of OS patients. CCK8 assay, colony formation assay, flow cytometry, and transwell assay were performed to determine the function of circ_0001658. Moreover, dual‐luciferase reporter gene assay was done to verify the targeting relationship between circ_0001658 and miR‐382‐5p. Compared with adjacent tissues, circ_0001658 displayed a significantly higher expression in OS tissues. Circ_0001658 could facilitate the proliferation, migration, and invasion of OS cells and impede apoptosis by sponging miR‐382‐5p. Further, circ_0001658 was proved to directly and negatively regulate the expression of miR‐382‐5 while positively modulate the expression of YB‐1. Circ_0001658 promotes the proliferation and metastasis of OS cells via modulating miR‐382‐5p/YB‐1 axis. Significance of the study: In recent years, the expression and function of circular RNA in cancer have been the focus of tumour research. The study on circular RNA helps elucidate the molecular pathology of tumorigenesis and cancer progression. This study demonstrated that circ_0001658 promotes the proliferation and metastasis of OS cells via modulating miR‐382‐5p/YB‐1 axis. To our best knowledge, this work is the first to study the expression and function of circ_0001658 in cancer. [ABSTRACT FROM AUTHOR]

With the swift progression of three-dimensional (3D) modeling and multimedia technology, the unauthorized duplication and manipulation of 3D point cloud data has become more prevalent. Existing watermarking algorithms designed for 3D point cloud data lack robustness against rotation, cropping, and random point addition attacks. To address the aforementioned issues, we propose a robust watermarking algorithm based on the Mahalanobis distance (MD) and feature point extraction, including zero-watermarking algorithm based on MD and watermarking algorithm based on the Intrinsic Shape signatures (ISS) feature points. Firstly, calculate the MD of point cloud data and use it to construct feature matrix. A zero-watermark image is constructed through the XOR operation of the feature matrix and the copyright information matrix. Secondly, ISS feature points can be extracted from point cloud data, which using the X and Y coordinates of the feature points as indexes. The color information of the feature points is used as host data to embed the watermark. The scale invariance of MD and the stability of ISS feature points augment the robustness of the algorithm. Experimental results demonstrate that the scheme we propose exhibits strong robustness against geometric attacks, simplification attacks, cropping attacks, reordering, and noise attacks while ensuring point cloud data coordinates are lossless. [ABSTRACT FROM AUTHOR]

Abstract This study investigates the effects of annealing temperature as well as time on the temperature coefficient of resistance (TCR) of nickel (Ni) films deposited on flexible polyimide substrate by direct current magnetron sputtering. The morphological and microstructural characteristics of as-deposited and annealed Ni films were analyzed to understand the mechanisms of TCR variation. The crystalline phase, grain size change tendency and residual stress of films were evaluated by X-ray Diffractometer (XRD) technique. (111) is the preferred orientation of Ni and the grains have a growth after annealing. The residual stress in as-deposited films is about −446.3 MPa and reduced to −208.8 MPa after annealing at 400 °C for 6 h. Focused Ion Beam Electron Microscope (FIBEM) and Energy Dispersive X-ray Spectroscopy (EDS) investigations showed the microstructure of annealed films has a relative improvement and the oxygen content was little increased with increasing annealing temperature and time. Mean surface roughness determined by Atomic Force Microscope (AFM) is decreased from 4.5 nm to 1.25 nm with increasing annealing temperature. The TCR value increases with the increasing annealing temperature and time. When the annealing time exceeds 6 h, the TCR almost has no change or even begin to decline. Highlights • Annealing treatment resulted in larger grain size, residual stress relaxation and smaller surface roughness of Ni films. • The TCR shows a significant increase with the increasing annealing temperature below 400℃ and time below 6 h. • The TCR shows saturated value after 6 h annealing indicated the Ni films reach stable state within 6 h. [ABSTRACT FROM AUTHOR]

Genetic sub-populations (clades) of cosmopolitan marine diatom Pseudo-nitzschia pungens might have distinct habitats, and their hybrid zone is suspected in higher latitude area of the West Pacific area, however, it is still unrevealed because of technical difficulties and lack of evidences in natural environments. The aim of this study is to investigate the habitat characteristics of each clade of P. pungens on geographical distribution with the habitat temperature ranges of each clade and to reveal their hybrid zone in the West Pacific area. We employed the 137 number of nucleotide sequences of P. pungens and its sampling data (spatial and temporal scale) originated from the West Pacific area, and used field application of qPCR assay for intra-specific level of P. pungens . Only two genotypes, clade I and III, were identified in the West Pacific area. Clade I was distributed from 39 to 32.3°N, and clade III were from 1.4 to 34.4°N. The estimated habitat temperature for the clade I and clade III ranges were 8.1–26.9 °C and 24.2–31.2 °C, respectively. The latitudinal distributions and temperature ranges of each clade were significantly different. The qPCR assay employed, and results suggested that the hybrid zone for clade I and III has been observed in the southern Korean coasts, and clade III might be introduced from the Southern Pacific area. The cell abundances of clade III were strongly related with the higher seawater temperature and warm current force. This study has defined distinct habitat characteristics of genetically different sub-populations of P. pungens , and revealed its hybrid zone in natural environment for the first time. We also provided strong evidences about dispersion of the population of clade III to higher latitude in the West Pacific area. [ABSTRACT FROM AUTHOR]

Many achnanthoid diatoms were transferred from Achnanthes or Achnanthidium to new genera based on characteristics observed via scanning electron microscopy (SEM). In this study, we isolated and cultured two Korean freshwater achnanthoid diatoms (Bacillariophyceae), studied their morphological characteristics using SEM, and assessed their molecular characteristics by analysing the nuclear small subunit (SSU) and ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcL) genes. We emended the description of Lemnicola hungarica with regard to the spindly pore opening of the hymen and the internally convex occlusions of elongated pores on the mantle. In addition, we demonstrated that the valves of L. hungarica are occasionally biseriate to uniseriate towards the valve edge. A morphological comparison of Lemnicola strains and species showed that biseriate rows of areolae are no longer an essential characteristic for allocation to Lemnicola. Based on the SEM and molecular analysis results, we also established a new, small-celled monoraphid species, Lemnicola uniseriata sp. nov., which has elongated areolae occluded by radiately structured hymenes and an elliptic valve shape. The uniseriate areolae of L. uniseriata showed that Lemnicola includes both uniseriate and biseriate striae. Additionally, the results of SSU and rbcL sequence analyses provided strong evidence to support the recognition of L. uniseriata as a new species. [ABSTRACT FROM AUTHOR]

In this study, Sm 3+ doped Na 0.5 La 0.5 Bi 8- x Sm x Ti 7 O 27 (NBT-BITL- x Sm, x = 0, 0.01, 0.015, 0.02, and 0.03) ceramics were synthesized via a conventional solid-state reaction process. The structural, electrical, and photoluminescence properties of NBT-BITL- x Sm ceramics were systematically investigated. The crystal structure of NBT-BITL- x Sm was refined using XRD Rietveld refinement and found to possess a single orthorhombic structure at room temperature. Raman spectroscopy revealed that Sm 3+ ions preferred to substitute for Bi 3+ located in the A-sites of pseudo-perovskite layers, inducing a slight decrease in orthorhombic distortion. Strong characteristic emission peaks of Sm 3+ ions were observed in orange-red regions under a 407 nm laser source, and the sample with x = 0.015 achieved the optimal photoluminescent property. Dielectric measurements showed double anomaly permittivity peaks at the temperature of 589 and 600 ∘ C ( T m and T c , respectively). The complex impedance spectrum indicated that the electrical conductivities mainly originated from crystal grains at high temperature. The activation energy was calculated to be 1.37–1.44 e V from Arrhenius fitting results. After Sm 3+ substitution, the activation energy for conductivity was increased as a result of reduced oxygen vacancies. [ABSTRACT FROM AUTHOR]

Bacteria constitute a large domain of prokaryotic microorganisms present in marine ecosystems and play a significant role in energy flow and nutrient cycling. Bacterial community changes may affect organisms of higher trophic levels. We conducted field monitoring to study the relationship between dissolved organic carbon (DOC) and the bacterial community in the coastal waters of Incheon, Korea. Results showed that abiotic factors, such as temperature, salinity, dissolved oxygen (DO), pH, and dissolved inorganic nutrients, were not significantly different among the sampling sites during the study period. On the other hand, nutrient conditions were significantly different among the sites between 2012-2013 and 2014. Nitrogen was the limiting factor from 2012 to 2013, and phosphate in 2014. Biotic data showed that DOC affected both bacterial abundance and bacterial composition. A similar fluctuation pattern was observed for phytoplankton and Chlorophyll a. However, a close correlation was not observed between phytoplankton and other variables. Redundancy analysis (RDA) and Pearson correlation analysis of abiotic and biotic factors also showed that DOC concentration and bacterial abundance were correlated. Therefore, DOC appears to be an important factor affecting bacterial abundance and composition in the coastal waters of Incheon, Korea. [ABSTRACT FROM AUTHOR]

The viscoelastic creep behaviour of a hot-mix asphalt (HMA) was experimentally investigated via uniaxial compressive creep tests subjected to eight given stress levels of 0.1–0.8 MPa. The tests lasting for 3600 s were conducted on a MTS 809 Axial/Torsional Test System at 26 °C. The experimental results demonstrate that the creep compliance magnitude and its increment within the steady state creep tend to decrease as the applied stress increases. The Findley model, the simplified multiple integral model and the modified time-hardening model were employed to describe the creep behaviour of the HMA within the first two creep stages, and then competitively evaluated by three criteria. The result shows that the Findley model is superior to the others. Moreover, it has been proved that the modified time-hardening model is a special case of the Findley model. [ABSTRACT FROM AUTHOR]

Copepoda are one of the most significant animal groups present in aquatic ecosystems. Ecologists, evolutionary biologists, and biotechnologists continue to test new methods to study the application of Copepoda as model organisms in various fields of pure and applied science, from evolution and ecology to aquaculture as live feed, as biological control of mosquito larvae, as biological indicators of water and sediment quality, in environmental monitoring and as a source of protein in the food industry. This paper reviews the current progress and trends within copepod research from a number of different perspectives. We emphasize the importance of Copepoda and the necessity of strengthening research on various topics related to copepod biology, some of which are of great significance to local sustainable development. [ABSTRACT FROM AUTHOR]

A new marine diatom species, Auricula weizhouensis sp. nov., was isolated from Weizhou Island, Guangxi, China, and the morphology was examined in detail. The frustule was symmetrical and quadrate, with four rounded angles. The valve was longitudinally reniform. The vegetative cells of A. weizhouensis were 28.9–35.0 μm in length and 22.2–28.9 μm in width. The mature cingulum was composed of five to six open bands. A large plate-like chloroplast was observed on the ventral side of the girdle. There were 5–7 poroids per 1 μm in a row along the median line. The number of radiate and biforked striae was 15–19 per 10 μm on the ventral margin and 21–31 per 10 μm on the dorsal margin. Striae were biseriate with two rows of areolae (12–14 areolae per 1 μm). Both sides of the double-sigmoid raphe canal had a longitudinal costa. Approximately 21–31 fibulae per 10 μm were arrayed in a row on each longitudinal costa. More importantly, A. weizhouensis and Auricula densestriata could be distinguished from other Auricula species by their characteristic concave ventral margin, and the ventral margin of A. weizhouensis was approximately straight in the middle, whereas that of A. densestriata was inflected. In addition, molecular data from partial SSU rDNA sequences showed that A. weizhouensis (strain WZ-1704-E8) belonged to the genus Auricula, with Auricula complexa (KX120684) as the nearest neighbour (4.58% p-distance). Therefore, both morphological and phylogenetic analyses supported A. weizhouensis as a new species. [ABSTRACT FROM AUTHOR]

Most of the existing digital fingerprint algorithms for vector maps are symmetric fingerprint algorithms, and merchants may frame a legitimate buyer. An asymmetric fingerprinting protocol utilizing homomorphic encryption is proposed. First, the buyer encrypts his fingerprint. Then, this encrypted fingerprint and the merchant’s fingerprint are embedded into an encrypted vector map by the merchant. Finally, the encrypted data with the fingerprints of both parties is distributed to buyers. The buyer can use his private key to decrypt the encrypted data and get the Non-encrypted data with the fingerprints. In this way, merchants can track illegal users without the buyer’s fingerprint. Experimental results show that after various attacks, fingerprints can still be detected correctly. [ABSTRACT FROM AUTHOR]

Existing copyright protection schemes for 3D models of oblique photography predominantly utilize digital watermarking technology, most of which suffer from shortcomings such as the potential false accusation of legitimate users and the inability to effectively trace unauthorized distributors. In response to these challenges, this article proposes a homomorphic encryption domain asymmetric fingerprinting scheme for 3D models of oblique photography. Initially, the fingerprints to be embedded are collaboratively generated by the transacting parties, with the publisher remaining unaware of the user's actual fingerprint. This approach ensures the effective implementation of the asymmetric nature of the fingerprinting scheme. Subsequently, potential geometric and non‐geometric attacks are considered prior to fingerprint embedding. Robustness is enhanced for the proposed solution through relative coordinate transformations and normalization procedures. Ultimately, the embedding and extraction of fingerprints are achieved through the application of an effective bit parity check method, in conjunction with the vertex‐paradigm projection length mapping mechanism and the Paillier homomorphic encryption system, minimizing embedding distortion while ensuring data security. Experimental results demonstrate that the proposed solution exhibits satisfying robustness against common manipulations, such as cropping, simplification, and geometric attacks. Additionally, the scheme effectively safeguards legitimate users from false accusations and accurately traces maliciously authorized users. [ABSTRACT FROM AUTHOR]

Vibrio is a salt‐tolerant heterotrophic bacterium that occupies an important ecological niche in marine environments. However, little is known about the contribution of resource diversity to the marine Vibrio diversity and community stability. In this study, we investigated the association among resource diversity, taxonomic diversity, phylogenetic diversity, and community stability of marine Vibrio in the Beibu Gulf. V. campbellii and V. hangzhouensis were the dominant groups in seawater and sediments, respectively, in the Beibu Gulf. Higher alpha diversity was observed in the sediments than in the seawater. Marine Vibrio community assembly was dominated by deterministic processes. Pearson's correlation analysis showed that nitrite (NO2−$$ {\mathrm{NO}}_2^{-} $$‐N), dissolved inorganic nitrogen (DIN), ammonium (NH4+$$ {\mathrm{NH}}_4^{+} $$‐N), and pH were the main factors affecting marine Vibrio community stability in the surface, middle, and bottom layers of seawater and sediment, respectively. Partial least‐squares path models (PLS‐PM) demonstrated that resource diversity, water properties, nutrients, and geographical distance had important impacts on phylogenetic and taxonomic diversity. Regression analysis revealed that the impact of resource diversity on marine Vibrio diversity and community stability varied across different habitats, but loss of Vibrio diversity increases community stability. Overall, this study provided insights into the mechanisms underlying the maintenance of Vibrio diversity and community stability in marine environments. [ABSTRACT FROM AUTHOR]

Vibrio is a salt‐tolerant heterotrophic bacterium that occupies an important ecological niche in marine environments. However, little is known about the contribution of resource diversity to the marine Vibrio diversity and community stability. In this study, we investigated the association among resource diversity, taxonomic diversity, phylogenetic diversity, and community stability of marine Vibrio in the Beibu Gulf. V. campbellii and V. hangzhouensis were the dominant groups in seawater and sediments, respectively, in the Beibu Gulf. Higher alpha diversity was observed in the sediments than in the seawater. Marine Vibrio community assembly was dominated by deterministic processes. Pearson's correlation analysis showed that nitrite (NO2−$$ {\mathrm{NO}}_2^{-} $$‐N), dissolved inorganic nitrogen (DIN), ammonium (NH4+$$ {\mathrm{NH}}_4^{+} $$‐N), and pH were the main factors affecting marine Vibrio community stability in the surface, middle, and bottom layers of seawater and sediment, respectively. Partial least‐squares path models (PLS‐PM) demonstrated that resource diversity, water properties, nutrients, and geographical distance had important impacts on phylogenetic and taxonomic diversity. Regression analysis revealed that the impact of resource diversity on marine Vibrio diversity and community stability varied across different habitats, but loss of Vibrio diversity increases community stability. Overall, this study provided insights into the mechanisms underlying the maintenance of Vibrio diversity and community stability in marine environments. [ABSTRACT FROM AUTHOR]

A flexible hot-film sensor array for wall shear stress, flow separation, and transition measurement has been fabricated and implemented in experiments. Parylene C waterproof layer is vapor phase deposited to encapsulate the sensor. Experimental studies of shear stress and flow transition on a flat plate have been undertaken in a water tunnel with the sensor array. Compared with the shear stress derived from velocity profile and empirical formulas, the measuring errors of the hot-film sensors are less than 5%. In addition, boundary layer transition of the flat plate has also been detected successfully. Ensemble-averaged mean, normalized root mean square, and power spectra of the sensor output voltage indicate that the Reynolds number when transition begins at where the sensor array located is 1.82 × 105, 50% intermittency transition is 2.52 × 105, and transition finishes is 3.96 × 105. These results have a good agreement with the transition Reynolds numbers, as measured by the Laser Doppler Velocimetry (LDV) system. [ABSTRACT FROM AUTHOR]

Microbial interactions including competition, mutualism, commensalism, parasitism, and predation, which can be triggered by nutrient acquisition and chemical communication, are universal phenomena in the marine ecosystem. The interactions may influence the microbial population density, metabolism, and even their environmental functions. Herein, we investigated the interaction between a heterotrophic bicosoecid flagellate, Pseudobodo sp. (Bicoecea), and a dinoflagellate, Gambierdiscus balechii (Dinophyceae), which is a well-known ciguatera food poisoning (CFP) culprit. The presence of Pseudobodo sp. inhibited the algal proliferation and decreased the cardiotoxicity of zebrafish in the algal extract exposure experiment. Moreover, a significant difference in microbiome abundance was observed in algal cultures with and without Pseudobodo sp. Chemical analysis targeting toxins was performed by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) combined with molecular networking (MN), showing a significant alteration in the cellular production of gambierone analogs and some super-carbon chain compounds. Taken together, our results demonstrated the impact of heterotrophic flagellate on the photosynthetic dinoflagellates, revealing the complex dynamics of algal toxin production and the ecological relationships related to dinoflagellates in the marine environment. [ABSTRACT FROM AUTHOR]

The identification and quantification of Heterosigma akashiwo cysts in sediments by light microscopy can be difficult due to the small size and morphology of the cysts, which are often indistinguishable from those of other types of algae. Quantitative real-time PCR (qPCR) based assays represent a potentially efficient method for quantifying the abundance of H. akashiwo cysts, although standard curves must be based on cyst DNA rather than on vegetative cell DNA due to differences in gene copy number and DNA extraction yield between these two cell types. Furthermore, qPCR on sediment samples can be complicated by the presence of extracellular DNA debris. To solve these problems, we constructed a cyst-based standard curve and developed a simple method for removing DNA debris from sediment samples. This cyst-based standard curve was compared with a standard curve based on vegetative cells, as vegetative cells may have twice the gene copy number of cysts. To remove DNA debris from the sediment, we developed a simple method involving dilution with distilled water and heating at 75°C. A total of 18 sediment samples were used to evaluate this method. Cyst abundance determined using the qPCR assay without DNA debris removal yielded results up to 51-fold greater than with direct counting. By contrast, a highly significant correlation was observed between cyst abundance determined by direct counting and the qPCR assay in conjunction with DNA debris removal (r2 = 0.72, slope = 1.07, p < 0.001). Therefore, this improved qPCR method should be a powerful tool for the accurate quantification of H. akashiwo cysts in sediment samples. [ABSTRACT FROM AUTHOR]

Fungi from the genus Aspergillus are important resources for the discovery of bioactive agents. This investigation characterized the isolation, structural elucidation, and antimicrobial evaluation of 46 metabolites produced by the marine-derived fungus Aspergillus sp. ZZ1861 in rice solid and potato dextrose broth liquid media. The structures of these isolated compounds were determined based on their HRESIMS data, NMR spectral analyses, and data from ECD, NMR, and optical rotation calculations. Emericelactones F and G, 20 R ,25 S -preshamixanthone, 20 R ,25 R -preshamixanthone, phthalimidinic acid A, phthalimidinic acid B, aspergilol G, and 2-hydroxyemodic amide are eight previously undescribed compounds and (S)-2-(5-hydroxymethyl-2-formylpyrrol-1-yl) propionic acid lactone is reported from a natural resource for the first time. It is also the first report of the configurations of 25 S –O-methylarugosin A, 25 R -O-methylarugosin A, 5 R -(+)-9-hydroxymicroperfuranone, and 5 R -(+)-microperfuranone. Phthalimidinic acid A, phthalimidinic acid B, aspergilol G, and 2-hydroxyemodic amide have antifungal activity against Candida albicans with MIC values of 1.56, 3.12, 1.56, and 12.5 μg/mL, respectively, 20 R ,25 S -preshamixanthone (MIC 25 μg/mL) shows antibacterial activity against Escherichia coli , and 20 R ,25 R -preshamixanthone exhibits antimicrobial activity against all three tested pathogens of methicillin-resistant Staphylococcus aureus , E. coli , and C. albicans with MIC values of 50, 25, 25 μg/mL, respectively. Eight previously undescribed compounds were isolated and characterized from the marine-derived fungus Aspergillus sp. ZZ1861. Phthalimidinic acid A, phthalimidinic acid B, aspergilol G, and 2-hydroxyemodic amide have antifungal activity against Candida albicans. [Display omitted] • Forty-six metabolites were isolated from a marine fungus Aspergillus sp. ZZ1861. • Eight metabolites were identified as previously undescribed compounds. • Phthalimidinic acids A and B, aspergilol G, and 2-hydroxyemodic amide showed antifungal activity. [ABSTRACT FROM AUTHOR]

Rare earth (Eu3+)‐modified Pb(Mg1/3Nb2/3)O3‐PbTiO3 (PMN‐PT) polycrystalline ferroelectric ceramics were fabricated by high‐temperature solid‐state sintering, the phase structure, dielectric and piezoelectric properties were investigated. Eu3+ addition was found to significantly improve dielectric and piezoelectric properties of PMN‐PT, where the optimized properties were achieved for the composition of 2.5 mol%Eu: 0.72PMN‐0.28PT, with the piezoelectric d33 = 1420 pC/N, dielectric εr = 12 200 and electromechanical k33 = 0.78, respectively. All these results indicate that the Eu3+‐doped PMN‐PT ceramics are promising candidates for high‐performance room‐temperature piezoelectric devices. [ABSTRACT FROM AUTHOR]

Three genetic sub-populations (clade I, II and III) of Pseudo-nitzschia pungens , the potential toxic marine diatom, are known to have distinguishable growth characteristics under different culture conditions and distinct distributed patterns in the world. However, to date their exact eco-physiological traits are unrevealed in fields due to lack of the method to detect and/or measure abundances of each sub-populations, hence, the qPCR (quantitative real-time polymerase chain reaction) assay was developed to detect and quantify the P. pungens cells of each clade. Designed two specific primer sets, Pcla12F/R (for clade I and II) and Pcla3F/R (for clade III) only could amplify each target genomic DNA. The, significant linear relationships (R 2 > 0.998) was established between C t (threshold cycle) value and the log of cell abundance for each clade. Through the melting curve analysis, comparisons for gene copy numbers among the three clades and spike test for field study, our qPCR assay was reliable to quantify the cell numbers of each clade. There was strong linear correlation (R 2 > 0.990) between cell abundances as estimated by qPCR assay and direct counting via light microscope in spike test, and 0.24 (clade I), 0.25 (clade II) and 0.33 (clade III) P. pungens cells per mL were detected markedly upon the use of specific two-primer set. Finally, developed qPCR assay was applied on field samples successfully. Our study implicate that our qPCR assay is an accurate and sensitive technique to estimate the cell abundances of each clade of P. pungens in field works. [ABSTRACT FROM AUTHOR]

• Prorocentrum donghaiense is the most notorious HAB species in the East China Sea. • Blooms of P. donghaiense in the East China Sea are results of temperature increase and eutrophication. • Phosphorous deficiency plays a critical role in regulating P. donghaiense blooms. • The major harmful consequence of P. donghaiense blooms is disruption of ecosystems. Prorocentrum donghaiense Lu (also identified as Prorocentrum shikokuense Hada and Prorocentrum obtusidens Schiller) is a bloom-forming dinoflagellate species distributed worldwide. Blooms of P. donghaiense occur annually in adjacent waters of the East China Sea (ECS), especially in the waters near the Changjiang River Estuary. Blooms of this species have also been reported in nearby Japanese and Korean waters. There has been an apparent bloom-forming species succession pattern in the ECS since 2000, with diatom blooms in the early spring, shifting to long-lasting and large-scale dinoflagellate blooms dominated by P. donghaiense during the spring, and finally ended by diatom and/or Noctiluca scintillans blooms in summer. These bloom succession patterns were closely correlated with changes in environmental factors, such as temperature increase and anthropogenic eutrophication. Decreasing silicate by the construction of the Three Gorges Dam and increasing dissolved inorganic nitrogen flux were mainly influenced by high intensity human activities in the Changjiang River watershed, resulting in low Si/N ratio and high N/P ratios, possibly accelerating outbreak of P. donghaiense blooms. Phosphorous deficiency might be the most critical factor controlling the succession of microalgal blooms from diatoms to dinoflagellates. Prorocentrum donghaiense is a nontoxic species, but it can disrupt marine ecosystem by decreasing phytoplankton biodiversity and changing the structure of the food chain. Prorocentrum donghaiense blooms in the ECS have been intensively studied during the last two decades. Several possible mechanisms that contribute or trigger the annual blooms of this species have been proposed, but further research is required particularly on the aspect of nutrient budget, ecosystem impacts, as well as social-economic impact assessment. [ABSTRACT FROM AUTHOR]

Three clades of Pseudo-nitzschia pungens, determined by the internal transcribed space ( ITS) region, are distributed throughout the world. We studied 15 P. pungens clones from various geographical locations and confirmed the existence of the three clades within P. pungens, based on ITS sequencing and described the three subgroups (IIIaa, IIIab, and IIIb) of clade III. Clade III (clade IIIaa) populations were reported for the first time in Korean coastal waters and the East China Sea. In morphometric analysis, we found the ultrastructural differences in the number of fibulae, striae, and poroids that separate the three clades. We carried out physiological tests on nine clones belonging to the three clades growing under various culture conditions. In temperature tests, only clade III clones could not grow at lower temperatures (10°C and 15°C), although clade I and II clones grew well. The estimated optimal growth range of clade I clones was wider than that of clades II and III. Clade II clones were considered to be adapted to lower temperatures and clade III to higher temperatures. In salinity tests, clade II and III clones did not grow well at a salinity of 40. Clade I clones were regarded as euryhaline and clade II and III clones were stenohaline. This supports the hypothesis that P. pungens clades have different ecophysiological characteristics based on their habitats. Our data show that physiological and morphological features are correlated with genetic intraspecific differentiation in P. pungens. [ABSTRACT FROM AUTHOR]

As a marine ichthyotoxic dinoflagellate, Margalefidinium polykrikoides, previously named Cochlodinium polykrikoides, have caused mass mortalities of fish worldwide during blooms. Rapid detection of target species is a prerequisite for the timely monitoring and early warning of harmful algal blooms (HABs). However, it is difficult to achieve rapid identification with traditional methods. The technology of using quantitative real-time PCR (qPCR) to detect and quantify microalgae is relatively mature. Based on the accuracy, rapidity, and sensitivity of qPCR technology, it can be used in the monitoring and development of early warning systems for HABs. From 2017 to 2020, samples were collected from 15 locations off the Chinese coast or from local sea areas. Based on the qPCR detection and analysis, the target species, M. polykrikoides (East Asian ribotype, EAr), was found in samples from Tianjin, Yangtze River estuary, and offshore Fujian (East China Sea). This is the first time that M. polykrikoides (EAr) was detected in the coastal waters of Tianjin. The results reveal a distributive pattern of M. polykrikoides (EAr) along Chinese coastal waters. It is helpful to predict the future diffusion trend of M. polykrikoides (EAr) in the China Sea and provides a practical case for the future construction of monitoring and warning systems for M. polykrikoides and HABs. [ABSTRACT FROM AUTHOR]

Ciguatera poisoning is mainly caused by the consumption of reef fish that have accumulated ciguatoxins (CTXs) produced by the benthic dinoflagellates Gambierdiscus and Fukuyoa. China has a long history of problems with ciguatera, but research on ciguatera causative organisms is very limited, especially in the Beibu Gulf, where coral reefs have been degraded significantly and CTXs in reef fish have exceeded food safety guidelines. Here, five strains of Gambierdiscus spp. were collected from Weizhou Island, a ciguatera hotspot in the Beibu Gulf, and identified by light and scanning electron microscopy and phylogenetic analyses based on large and small subunit rDNA sequences. Strains showed typical morphological characteristics of Gambierdiscus caribaeus, exhibiting a smooth thecal surface, rectangular-shaped 2′, almost symmetric 4″, and a large and broad posterior intercalary plate. They clustered in the phylogenetic tree with G. caribaeus from other locations. Therefore, these five strains belonged to G. caribaeus, a globally distributed Gambierdiscus species. Toxicity was determined through the mouse neuroblastoma assay and ranged from 0 to 5.40 fg CTX3C eq cell−1. The low level of toxicity of G. caribaeus in Weizhou Island, with CTX-contaminated fish above the regulatory level in the previous study, suggests that the long-term presence of low toxicity G. caribaeus might lead to the bioaccumulation of CTXs in fish, which can reach dangerous CTX levels. Alternatively, other highly-toxic, non-sampled strains could be present in these waters. This is the first report on toxic Gambierdiscus from the Beibu Gulf and Chinese waters and will provide a basis for further research determining effective strategies for ciguatera management in the area. [ABSTRACT FROM AUTHOR]

• Aside from East Asia, historical records also showed the wide distribution of harmful raphidophyte Chattonella in Southeast Asian coastal waters. • Only one genotype, Chattonella marina complex, has been observed in East Asia. • Two Chattonella genotypes, C. marina complex and C. subsalsa , have occurred in Southeast Asia and were associated with fisheries damage. • Oboe-shaped mucocyst was observed from the cultures of C. marina from Indonesia, Malaysia, Japan and Russia for the first time. Red tides and associated fisheries damage caused by the harmful raphidophyte Chattonella were reassessed based on the documented local records for 50 years to understand the distribution and economic impacts of the harmful species in the Western Pacific. Blooms of Chattonella with fisheries damage have been recorded in East Asia since 1969, whereas they have been only recorded in Southeast Asia since the 1980s. Occurrences of Chattonella have been documented from six Southeast Asian countries, Indonesia, Malaysia, Philippines, Singapore, Thailand and Viet Nam, with mass mortalities mainly of farmed shrimp in 1980–1990s, and farmed fish in 2000–2010s. These occurrences have been reported with the names of C. antiqua, C. marina, C. ovata, C. subsalsa and Chattonella sp., owing to the difficulty of microscopic species identification, and many were not supported with molecular data. To determine the distribution of C. marina complex and C. subsalsa in Southeast Asia, molecular phylogeny and microscopic observation were also carried out for cultures obtained from Indonesia, Malaysia, Japan, Philippines, Russia, Singapore and Thailand. The results revealed that only the genotype of C. marina complex has been detected from East Asia (China, Japan, Korea and Russia), whereas both C. marina complex (Indonesia and Malaysia) and C. subsalsa (Philippines, Singapore and Thailand) were found in Southeast Asia. Ejection of mucocysts has been recognized as a diagnostic character of C. subsalsa , but it was also observed in our cultures of C. marina isolated from Indonesia, Malaysia, Japan, and Russia. Meanwhile, the co-occurrences of the two harmful Chattonella species in Southeast Asia, which are difficult to distinguish solely based on their morphology, suggest the importance of molecular identification of Chattonella genotypes for further understanding of their distribution and negative impacts. [ABSTRACT FROM AUTHOR]

Piezoelectric actuators are essential for numerous electromechanical applications, because of their advantages of high resolution, large generated forces, no friction, low heat dissipation and fast response. The design of the next-generation piezoelectric actuators is desired to meet the complex needs of advanced machines and instruments, where the high-performance and stable output under the combined thermal and mechanical loads are expected. However, simultaneously achieving high-performance and good temperature stability of piezoelectric actuators is a challenge, which hinders the use temperature range in practical applications. Here, in the studied Sm-doped Pb(Mg 1/3 Nb 2/3)O 3 -PbZrO 3 -PbTiO 3 system, the high piezoelectric strain coefficient d 33 * = 870 pm/V with superior temperature stability (below 7% variation over the temperature of 20°C to 280°C), together with negligible property degradation up to 106 cycles was successfully achieved. The outstanding blocking stress of 37.2 MPa and mechanical work of 6.4 kJ/m3 were obtained under the driving electric field of 15 kV/cm. This work provides a paradigm to achieve high piezoelectric strain properties with good temperature stability, where the studied materials are expected to greatly benefit the development of high temperature piezoelectric actuator applications. [Display omitted] [ABSTRACT FROM AUTHOR]