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The wildfire disease on tobacco can seriously hinder plants. Meanwhile, its pathogen, Pseudomonas syringae, can also infect over 200 plants and threat agriculture production. However, the disease usually occurs after summer rains which washes away most copper (Cu)-based bactericides, allowing the disease to invade. Therefore, we fabricate a new nanogel with high disease control and anti-erosion ability and study the effects of the reductant on the performance of the copper oxide nanoparticle (CuONP) composite nanogel.Polydopamine (PDA) is a polycation for both in situ reduction of CuONP in alginate nanogels and for adjusting the copper ion (CuThe addition of polycations (like PDA) into CuONP composite nanogel could increase the Cu

The characteristics of wave spectra in the swell-dominated seas in the Chancay Bay, Peru, and off the coast of Hambantota, Sri Lanka, were studied based on in situ measurements. According to the characteristics of the spectral shapes, the measured wave spectra were divided into single- and double-peaked spectra. For the single-peaked measured spectra, many widely used wave spectrum models were adopted to fit the measured wave spectra. By comparing the fitting results with the measured wave spectra, these wave spectra were insufficient for describing the peak enhancement or the high-frequency tail shape of the measured spectra. The spectral shape parameters were found to play an important role in the expression of the spectrum models. The peak enhancement factor γ in the Joint North Sea Wave Project (JONSWAP) spectra could adjust the peak height of the spectrum and the shape parameter m of the spectrum high-frequency tail in the Wallops spectra made the wave spectrum more flexible. Therefore, an improved single-peaked wave spectrum was proposed by combining the JONSWAP and Wallops spectra. It performed better than other spectrum models in describing the swell and has advantages in both the wave characteristic parameters and wave spectral shapes. The spectrum peak width parameter σ was relatively consistent in the two measurement stations and both around 0.24. Moreover, the proposed model overcame the limitations of the excessively high estimated slope in the high-frequency range of the Wallops spectrum; the shape parameter m of the spectrum high-frequency tail is primarily distributed in the range (1, 5). For the double-peaked measured spectra, the Ochi–Hubble spectrum was found to work better than the Torsethaugen spectrum.

Control of plant virus diseases largely depends on the induced plant defense achieved by the external application of synthetic chemical inducers with the ability to modify defense-signaling pathways. However, most of the molecular mechanisms underlying these chemical inducers remain unknown. Here, we developed a lentinan-loaded hydrogel with a core-shell structure and discovered how it protects plants from different virus infections. The hydrogel was synthesized by adding a chitosan shell on the surface of the polyanion sodium alginate-Ca -lentinan (LNT) hydrogel (SL-gel) to form a CSL-gel. CSL-gels exhibit the capacity to prolong the stable release of lentinan and promote Ca release. Application of CSL-gels on the root of plants induces broad-spectrum resistance against TMV, TRV, PVX and TuMV). RNA-seq analysis identified that the calmodulin-like protein 19 gene ( NbCML19) is upregulated by the sustained release of Ca from the CSL-gel, and silencing and overexpression of NbCML19 alter the susceptibility and resistance of tobacco to TMV. Our findings provide evidence that this novel and synthetic CSL-gel strongly inhibits the infection of plant viruses by the sustainable release of LNT and Ca . This study uncovers a novel mode of action by which CSL-gels trigger NbCML19 expression through the stable and sustained release of Ca .

Copper nanoparticles (CuNPs) can release copper ions (CuData showed that the CTAC coating would affect the antibacterial activity and leaf surface adhesion of the nanogel, while CuNP content could also influence the membrane damage ability of the gel. The nanogel could depress the growth of bacteria by rupturing its membrane and show a minimum inhibitory concentration (MIC) as low as 500 μg mLThe CuNP composite nanogel fabricated in this work performed high leaf disease controllability and safety compared to the commercial bactericide thiodiazole copper. We hope this nanogel can provide a potential high-efficiency nano-bactericide that can be used in the leaf bacterial disease control.

Silver (Ag)-containing agents or materials are widely used today in plant protection for their antimicrobial activity. In view of the superior inhibitory ability of biosynthesized (aldehyde-modified sodium alginate based) silver nanoparticles (AgNPs) against plant pathogenic fungi in our previous research, here we explored the antagonistic effect of biosynthesized AgNPs on plant pathogenic bacteria and the underlying mechanism. We selected Pseudomonas syringae pv. tabaci, the causal agent of tobacco wildfire disease, as the target and found that 1.2 μg/mL biosynthesized AgNPs completely inhibited the growth of P. syringae pv. tabaci in vitro and in vivo by partly destroying the cell membrane structure of the pathogen, resulting in cytoplasmic leakage. Moreover, Nicotiana benthamiana treated with 1.2 μg/mL biosynthesized AgNPs exhibited a significant upregulation of nonexpressor of pathogenesis-related genes 1 (NPR1) and pathogenesis-related gene 2 (PR2), the typical markers of the salicylic acid (SA)-mediated defense system, and an increase in peroxidase (POD) and polyphenol oxidase (PPO) activities as well as the production of reactive oxygen species (ROS). Furthermore, biosynthesized AgNPs treatment increased the chlorophyll content and dry weight of N. benthamiana. Overall, we demonstrated that biosynthesized AgNPs at a low concentration have high inhibitory effect on the pathogen causing tobacco wildfire disease by destroying bacterial cell membrane and inducing defense resistance in host plant. These results lay a theoretical foundation for further application of biosynthesized AgNPs in the control of plant bacterial diseases.

Although ε-poly-l-lysine (ε-PL) has a good potential as a green fungicide, high concentration is usually required during its controlling of plant disease. On the other hand, same problems also appeared in the study of CuONP based nano pesticides. In this manuscript, a new composite alginate nanogel (ALGNP) that containing CuONP and ε-PL was fabricated via in situ reduction of CuONP in nanogel and ε-PL surface coating. Based on the chelation of amide bond of ε-PL and Cu

Calcium is an important plant immune signal that is essential for activating host resistance, but how RNA viruses manipulate calcium signals to promote their infections remains largely unknown. Here, we demonstrated that tobacco mosaic virus (TMV) coat protein (CP)-interacting protein L (IP-L) associates with calmodulin-like protein 30 (NbCML30) in the cytoplasm and nucleus, and can suppress its expression at the nucleic acid and protein levels. NbCML30, which lacks the EF-hand conserved domain and cannot bind to Ca

Purpose This study aims to explore the radioprotective effects of recombinant human erythropoietin (rhEPO) on rats' submandibular gland hypofunction induced by irradiation (IR). Materials and Methods Thirty rats were divided into 3 groups: 1) control group, 2) IR group, and 3) IR + rhEPO group. The IR group and IR + rhEPO group received a single dose of 15 Grays (Gy) (0.98 Gy/min), plus, the IR + rhEPO group also received subcutaneous administration of rhEPO at a dose of 3,000 IU/kg body weight 3 days before irradiation and then repeated every 24 hours for the first 2 weeks after irradiation. Immunohistochemistry analysis to erythropoietin receptor was performed to detect the levels of erythropoietin receptor in submandibular glands with or without radiation. Ninety days after irradiation, the salivary flow rates were assessed, and the submandibular gland of every rat was subjected to hematoxylin and eosin staining and immunohistochemical staining with antiaquaporin 5 and anti–proliferating cell nuclear antigen antibodies. Apoptosis was examined by the terminal deoxynucleotidyl transferase biotin-dUDP nick end-labeling assay. In addition, to examine the protective role of rhEPO on human submandibular gland cells, the apoptotic and proliferation rate of cells under a radiation dose of 8 Gy was detected. One-way analysis of variance was carried out to analyze the results of each group, and the P value was set at 0.05. Results Erythropoietin receptor was expressed in the submandibular glands at a low level under normal conditions but upregulated after irradiation. rhEPO administration remarkably alleviated gland atrophy, increased salivary flow rates with upregulation of aquaporin-5 compared with the IR group. In addition, fewer apoptotic cells and more proliferative cells were observed in the IR + rhEPO group compared with the IR group, both in vivo and in vitro. Conclusions rhEPO administration may be a useful countermeasure to mitigate submandibular gland hypofunction after therapeutic radiation exposure.

This paper proposes a 3-D non-hydrostatic free surface flow model with a newly proposed general boundary-fitted grid system to simulate the nonlinear interactions of the bi-chromatic deep-water gravity waves. First, the monochromatic bidirectional and bi-chromatic bidirectional waves of small wave steepness are successively simulated to verify the abilities of the numerical model. Then, a series of bi-chromatic progressive waves of moderate wave steepness and different crossing angles are simulated and analyzed in detail. It is found that if the crossing angle is close to or smaller than the resonant angle, apparent discrepancies are observed among the numerical results, the linear wave theory, and the steady third-order theory. Otherwise, the three solutions coincide well. Through analysis, it is concluded that the discrepancies are caused by the third-order quasi-resonant interactions between the bi-chromatic progressive waves. Such interactions not only could modify the wave spectrum, but could also change the wave shape patterns.

Improving the efficiency and prolonging the duration of pesticides are of great significance in agricultural production. In this work, based on the antiviral compound chloroinconazide (CHI) synthesized previously, the improvement of the fabricated CHI-loaded alginate-based nanogel (CHI@ALGNP) was studied. It was found that CHI@ALGNP showed higher foliar adhesion than CHI and exhibited a sustained release for up to 7 days. CHI@ALGNP could also continuously activate the reactive oxygen species and antioxidant levels and induce the increase of salicylic acid content and the expression of its responsive gene PR2 for a long time, thus achieving sustained resistance to tobacco mosaic virus infection in Nicotiana benthamiana. Strikingly, CHI@ALGNP could release Ca2+ and Mg2+ to promote the growth of N. benthamiana. Taken together, for the first time, we have shown the improvement of a nanogel carrier to the antiviral activity and growth promotion of small molecular pesticides. As the alginate-based nanogel can be easily applied to the spray-based pesticide delivery technology, our study provides a new strategy for the development of new pesticide preparations and the application of multifunctional pesticides.

Background Emerging transcriptome-wide high-throughput screenings reveal the landscape and functions of RNAs, such as circular RNAs (circRNAs), in human cancer. In addition, the post-transcriptional RNA internal modifications, especially N6-methyladenosine (m6A), greatly enrich the variety of RNAs metabolism. However, the m6A modification on circRNAs has yet to be addressed. Results Here, we report an epitranscriptome-wide mapping of m6A-modified circRNAs (m6A-circRNA) in oral squamous cell carcinoma (OSCC). Utilizing the data of m6A methylated RNA immunoprecipitation sequencing (MeRIP-seq) and m6A-circRNAs microarray, we found that m6A-circRNAs exhibited particular modification styles in OSCC, which was independent of m6A-mRNA. Besides, m6A modification on circRNAs frequently occurred on the long exons in the front part of the coding sequence (CDS), which was distinct from m6A-mRNA that in 3’-UTR or stop codon. Conclusion In conclusion, our work preliminarily demonstrates the traits of m6A-circRNAs, which may bring enlighten for the roles of m6A-circRNAs in OSCC.

In this paper, the interactions between extreme waves and a vertical cylinder are investigated through a 3-D two-phase flow model. The numerical model is verified and validated by experimental data. Then, two factors are considered, the global wave steepness and the frequency bandwidth of the wave groups, in the studies of the in-line wave forces and the wave run-up around a cylinder. It is found that both the in-line wave forces and the wave run-up are remarkably increased with the increase of the global wave steepness, whereas the effect of the frequency bandwidth on the in-line wave forces is relatively weak in comparison with its effect on the wave run-up. The minimum and maximum wave run-ups are located in the directions of 22.5° and 180° with respect to the direction of the incident waves, respectively. Additionally, a new empirical formula is proposed for predicting the in-line wave forces by using only the free surface elevations around the cylinder. The results of the formula agree well with the simulation results.

Circular RNAs (circRNAs) function as an essential regulator in the progression of oral squamous cell carcinoma (OSCC). However, the potential roles and mechanism of circRNAs in OSCC are still elusive. Here, this research investigates the roles and molecular mechanism of novel circRNA (circMDM2) in OSCC progression. Clinically, circMDM2 was overexpressed in OSCC tissue and cells, and the overexpression served as a poor prognostic factor for OSCC patients. Functionally, cellular experiments confirmed that circMDM2 accelerated OSCC cell proliferation and glycolysis in vitro and circMDM2 knockdown repressed the tumour growth in vivo. Mechanistically, circMDM2 sponged miR‐532‐3p to promote the hexokinase 2 (HK2), forming the circMDM2/miR‐532‐3p/HK2 axis. In conclusion, these findings demonstrated that circMDM2/miR‐532‐3p/HK2 axis promotes the proliferation and glycolysis of OSCC, rendering a potential diagnostic biomarker and prospective therapeutic target for OSCC.

N

Shubnikov-de Hass oscillations are directly observed in undoped antiferromagnetic topological insulator MnBi2Te4. With increasing magnetic fields, the oscillation period decreases gradually in the magnetic transition from canted antiferromagnetism to ferromagnetism and then saturates in high magnetic fields, indicating the field-induced evolution of the band structure. From the analysis of the high-field oscillations, a nontrivial Berry phase and a small effective mass are extracted, in agreement with the predicted Weyl semimetal phase in ferromagnetic MnBi2Te4. Furthermore, rotating the magnetization of MnBi2Te4 can lead to a splitting of the high-field oscillations, which suggests the enhanced asymmetry of the Weyl cones in tilted fields. Therefore, the observation of these magnetically tunable quantum oscillations clearly demonstrates the indispensable role of field in tuning the band structure or physical properties of MnBi2Te4., 13 pages, 5 figures

Emerging transcriptome-wide high-throughput screenings reveal the landscape and functions of RNAs, such as circular RNAs (circRNAs), in human cancer. In addition, the post-transcriptional RNA internal modifications, especially NHere, we report an epitranscriptome-wide mapping of mIn conclusion, our work preliminarily demonstrates the traits of m

A new modified nonlinear Schrödinger (MNLS) equation is derived for gravity waves with the presence of wind, dissipation, and shear currents in finite water depth. Horizontal surface currents are assumed stationary and slowly varying spatially. Using the MNLS equation, the modulational instability (MI) of deep-water gravity wave trains affected by wind and dissipation is considered. It was demonstrated that the modulational perturbation of waves is unstable or becomes unstable after several wave periods, whereas the dissipation will suppress the MI. Then, a new theoretical formula for predicting the maximum amplitude is derived to take into account the effect of vorticity, dissipation, and wind. The effect of dissipation becomes significant in strong currents, while wind can increase the height amplification. Furthermore, an explicit analytical Peregrine breather (PB) solution that considers the effect of vorticity, dissipation, and wind is presented. Opposing currents and winds will increase the height of PB. However, following currents and dissipation have opposite effects. The effects of the shear current, dissipation, and wind on nondimensional maximum amplitudes during the evolution of the Akhmediev breather are similar to PB solution.

Emerging transcriptome high throughput screenings reveal the landscape and functions of RNAs, such as circular RNAs (circRNAs), in human cancer. In addition, the post-transcriptional internal modifications, especially N6-methyladenosine (m6A), greatly enrich the variety of RNAs metabolism. However, the m6A modification on circRNAs has yet to be addressed. Here, we report an epitranscriptome-wide mapping of m6A-modified circRNAs (m6A-circRNA) in oral squamous cell carcinoma (OSCC). Utilizing the data of MeRIP-seq and m6A-circRNAs epitranscriptomic microarray analysis, we found that m6A-circRNAs exhibited their particular modification style in OSCC, which was independent of m6A-mRNA. Besides, m6A modification on circRNAs frequently occurred on the long exons in the front part of the coding sequence (CDS), which was distinct from m6A-mRNA that in 3’-UTR or stop codon. In conclusion, our work preliminarily demonstrates the traits of m6A-circRNAs and probed into the association of m6A-circRNAs and m6A-mRNA, which may bring enlighten for the roles of m6A-circRNAs in OSCC.

As a kind of promising nanopesticide, in contrast to traditional synthesis strategies, the application of a polysaccharide in silver nanoparticle preparation can improve its stability and avoid the usage of harmful substances. In this work, a two-step strategy for synthesizing silver nanoparticles (A-AgNPs) from aldehyde-modified sodium alginate (ASA) was introduced. The size of the A-AgNPs synthesized can be controlled from 6 to 40 nm with a high dispersibility in water. Furthermore, compared to naked AgNPs (n-AgNPs), the A-AgNPs showed improved broad-spectrum antimicroorganism activity. We found that the A-AgNPs mainly exerted their antifungal activity through the changing of cell membrane permeability and affecting the soluble protein synthesis, destruction of DNA structure, and inhibition of DNA replication. Meanwhile, the A-AgNPs showed no inhibition of rice and

Asparagine synthetase is a key enzyme that catalyses the conversion of amide groups from glutamine or ammonium to aspartate, which leads to the generation of asparagine. However, the role of asparagine synthetase in plant immunity remains largely unknown. Here, we identified a Nicotiana benthamiana asparagine synthetase B (NbAS‐B) that associates with tomato mosaic virus coat protein‐interacting protein L (IP‐L) using the yeast two‐hybrid assay and examined its role in tobacco mosaic virus (TMV) resistance. The association of IP‐L with NbAS‐B was further confirmed by in vivo co‐immunoprecipitation, luciferase complementation imaging, and bimolecular fluorescence complementation assays. IP‐L and NbAS‐B interact in the nucleus and cytosol and IP‐L apparently stabilizes NbAS‐B, thus enhancing its accumulation. The expressions of IP‐L and NbAS‐B are continuously induced on TMV‐green fluorescent protein (GFP) infection. Co‐silencing of IP‐L and NbAS‐B facilitates TMV‐GFP infection. Overexpression of NbAS‐B in tobacco reduces TMV‐GFP infection by significantly improving the synthesis of asparagine. Furthermore, the external application of asparagine significantly inhibits the infection of TMV‐GFP by activating the salicylic acid signalling pathway. These findings hold the potential for the future application of asparagine in the control of TMV., Nicotiana benthamiana asparagine synthetase B (NbAS‐B) interacts with interacting protein L (IP‐L), facilitating the accumulation of NbAS‐B and increasing asparagine content, thus providing enhanced resistance to tobacco mosaic virus through the asparagine‐induced salicylic acid signalling pathway.

In this research, the dopamine self-polymerization was used to coat polydopamine (PDA) on cellulose nanocrystal (CNC) surfaces, and we integrated the functionality and structural merits of the two components in poly(vinyl alcohol) (PVA) films at a nanometer scale. The results showed that coating PDA on CNCs led to a concurrent increase in strength and break elongation. With increasing PDA@CNC loading level, the Young’s modulus continuously increased, which could be ca. 3.1-fold over that of neat PVA film at a loading level of 15 wt%. Both tensile strength and breaking elongation of the nanocomposite reached the maximum values with 6 wt% PDA@CNC, which were 75.8% and 58.1% more than those of neat PVA, respectively. Besides, the maximum decomposition temperature shifted from 271.3 °C of neat PVA film to 278.5 °C of the nanocomposite containing 6 wt% PDA@CNC, and then was continuously elevated up to 328.2 °C when the PDA@CNC loading level reached 15 wt%. For packaging application, the PDA component contributed to the UV-shielding and radical-scavenging functions, and the PDA@CNC nanofiller reduced the permeability of oxygen and water–vapor into PVA-based composites. Overall, the integrated PDA@CNC nanofiller as an active ingredient enhanced the mechanical, thermal, and functional properties of the PVA-based materials, and hence intensified the potential of their packaging application.

Zinc ions (Zn

Background Antibacterial photocatalytic therapy has been employed as a promising strategy to combat antibiotic-resistant bacteria in the water disinfection field, especially some non-metal inorganic nanomaterials. However, their antibacterial activities on plant phytopathogens are poorly understood. Here, the photocatalytic antibacterial mechanism of the urea-synthesized graphitic carbon nitride nanosheets (g-C3 N4 nanosheets) against Pseudomonas syringae pv. tabaci was systematically investigated in vitro and in vivo. Results The g-C3 N4 nanosheets exhibited remarkable concentration-dependent and irradiation-time-dependent antibacterial properties, and the 0.5 mg mL-1 concentration ameliorated tobacco wildfire disease in host plants. Specifically, under visible irradiation, g-C3 N4 nanosheets produced numerous reactive oxygen species (ROS), supplementing the plentiful extracellular and intracellular ROS in bacteria. After exposing light-induced g-C3 N4 nanosheets for 1 h, 500 genes were differentially expressed, according to transcriptome analyses. Notably, the expression of genes related 'antioxidant activity' and 'membrane transport' was sharply upregulated, and those related to 'bacterial chemotaxis', 'biofilm formation', 'energy metabolism' and 'cell motility' were downregulated. After exposure for over 2 h, the longer-time pressure on the target bacteria cause the decreased biofilm formation and flagellum motility, further injuring the cell membranes leading to cytoplasm leakage and damaged DNA, eventually resulting in the bacterial death. Concomitantly, the attachment of g-C3 N4 nanosheets was a synergistic physical antibacterial pathway. The infection capacity assessment also supported the earlier supposition. Conclusion These results provide novel insights into the photocatalytic antibacterial mechanisms of g-C3 N4 nanosheets at the transcriptome level, which are expected to be useful for dissecting the response pathways in antibacterial activities and for improving g-C3 N4 -based photocatalysts practices in plant disease control. © 2021 Society of Chemical Industry.

Long waves with periods greater than tens of seconds propagating into a harbor may be trapped and significantly amplified, thereby resulting in detrimental effects on port operations. The water surface elevation in the Hambantota Port, Sri Lanka, was measured to investigate the low-frequency oscillations and their forcing mechanisms. Results show that the port is protected well from short waves with periods less than 30 s; however, the protection against long waves with periods larger than 30 s is inadequate. The spectral analyses identified four dominant periods within the low-frequency wave range. Modal analysis based on the extended mild-slope equation shows that the measured spectrum density for some dominant periods is low because the measurement point is close to the corresponding modal lines. Correlation analysis shows that low-frequency oscillations inside the Hambantota Port are excited directly by the low-frequency waves contained within the incident waves. The low-frequency waves outside the Hambantota Port are generated from the higher-frequency gravity waves (swell and wind waves) due to nonlinear interactions. Empirical formula is adopted to estimate the low-frequency wave height outside the Hambantota Port.

The characteristics of wave spectrum in the swell dominated seas (i.e., the Chancay Bay on the western coast of Peru) are studied based on directional wave spectra measured using the technique of acoustic Doppler current profiler (ADCP). According to the wave rose diagram and the measured wave spectra, this sea area is mainly affected by the swell of the southwest direction and the significant wave height is between 0.7m-2.6m. Moreover, the wave spectra feature the single-peaked spectra and the double-peaked spectra. The JONSWAP spectrum model is adopted to fit single-peaked swell spectra. A close agreement could be found between the observed and fitted spectrum parameters. Hence, the JONSWAP model can be used to describe the single-peaked swell spectra in the sea area studied in this work. As for the double-peaked spectrum, Ochi-Hubble double peak spectrum model and simplified Torsethaugen double peak spectrum model are adopted to fit the wave spectra, respectively. Comparing the fitting results of two double-peaked spectrum modal, it’s possible to conclude that the measured double-peaked spectra can be well represented by the Ochi-Hubble double peak spectrum model.

Long noncoding RNAs (lncRNAs) act as an initial factor and promoter in different tumors as a kind of ncRNAs. The length of them is >200 nucleotides opposite small ncRNAs. Increasing researches have proved that dysregulation lncRNA has been implicated in tumorigenesis. Small nucleolar RNA host gene 20 (SNHG20), a member of lncRNAs, expresses frequently in cancer types, such as hepatocellular carcinoma, ovarian cancer, colorectal cancer, and bladder cancer, contributing to cancer development and progression by transcriptional or posttranscriptional modifications. Not only does this review show the recent published literature concerning the biological functions but also demonstrates molecular mechanisms of SNHG20 among above multiple malignancies and others.

To obtain strong interfacial adhesion between basalt fiber (BF) and polyamide 6 (PA6) matrix, a multiscale graphene-basalt fiber reinforcement was introduced by directly coating graphene (GR) onto the surface of individual basalt fiber via polyurethane sizing agent. The GR on the surface of BF was homogeneous, and the microstructure of the interfacial region between BF and matrix could be adjusted by varying the content of GR in the sizing agent. Owing to the bridge effect of GR, a mechanical meshing nanoscale interfacial area was generated, which could enhance the interfacial adhesive between BF and PA6 matrix, and the stress transfer of the corresponding composites was improved. The uniform coating of GR on the surface of BF increased the storage modulus and Tg for the BF/PA6 composites and 18.2% and 34% improvement for their tensile and flexural strength. Compared with BF/PA6, the GR-BF/PA6 composites obtained a fairly low friction coefficient and highly wear-resisting property, which was explained by the improved interfacial adhesion, effective stress transfer and the highly unfolded feature and flexibility of the introduced GR. This work presents a suitable approach for industrial production that can improve the comprehensive performance of fiber-reinforced composites effectively.

Single Gaussian wave groups with different initial wave steepness e0 and width N are produced in laboratory in finite depth to study the nonlinear evolution, the extreme events and breaking. The results show that wave groups with larger e0 will evolve to be several envelope solitons (short wave groups). By analyzing geometric parameters, a break in the evolution of the wave elevation and asymmetric parameters after extreme wave may be an indicator for the inception of refocus and the maximal wave moving to the middle, namely, wave down-shift occurs. The analysis of the surface elevations with HHT (Hilbert-Huang Transform), which presents the concrete local variation of energy in time and frequency can be exhibited clearly, reveals that the higher frequency components play a major role in forming the extreme event and the contribution to the nonlinearity. Instantaneous energy and frequency in the vicinity of the extreme wave are also examined locally. For spilling breakers, the energy residing in the whole wave front dissipates much more due to breaking, while the energy in the rear of wave crest loses little, and the intra-wave frequency modulation increases as focus. It illustrates that the maximal first order instantaneous frequency f1 and the largest crest tend to emerge at the same time after extreme wave when significant energy dissipation happens, and vice versa. In addition, it shows that there is no obvious relation of the CDN (combined degree of nonlinearity) to the wave breaking for the single Gaussian wave group in finite water depth.

Periodic undulating topographies (such as sandwaves and sandbars) are very common in coastal and estuarine areas. Normally incident water surface waves propagating from open sea to coastal areas may interact strongly with such topographies. The wave reflection by the periodic undulating topography can be significantly amplified when the surface wavelength is approximately twice the wavelength of the bottom undulations, which is often called as Bragg resonant reflection. Although the investigations on the hydrodynamic characteristics related to Bragg reflection of a region of undulating topography have been widely implemented, the effects of Bragg reflection on harbors have not yet been studied. Bragg resonant reflection can effectively reduce the incident waves. Meanwhile, however, it can also significantly hinder the wave radiation from the harbor entrance to the open sea. Whether Bragg reflection can be utilized as a potential measure to alleviate harbor oscillations is unknown. In the present study, Bragg reflection and their interactions with the harbor are simulated using a fully nonlinear Boussinesq model, FUNWAVE 2.0. For the purpose, an elongated harbor with constant depth is considered, and a series of sinusoidal bars with various amplitudes and numbers are deployed outside the harbor. The incident waves considered in this paper include regular long waves and bichromatic short wave groups. It is revealed for the first time that for both kinds of incident waves, Bragg resonant reflection can significantly alleviate harbor resonance. The influences of the number and the amplitude of sinusoidal bars on the mitigation effect of harbor resonance and on the optimal wavelength of sinusoidal bars that can achieve the best mitigation effect are comprehensively investigated, and it is found that the former two factors have remarkable influences on the latter two parameters. The present research provides a new option for the mitigation of harbor oscillations via changing the bottom profile, which is feasible as long as the navigating depth is guaranteed.

Forecasting coastal infragravity (IG) waves is crucial in preventing coastal disasters caused by IG waves. In this study, the performance of the unstructured WAVEWATCH Ⅲ (WW3) in predicting coastal IG waves is comparatively assessed using in-situ wave measurements, considering the effects of numerical schemes, time steps, and IG-source parameterization methods. The wave measurements are performed using three acoustic sensors installed at the coast of south Sri Lanka, with two being near or inside a harbor. Sensitivity analysis of the numerical schemes and time steps shows that the explicit scheme combined with a small time step leads to unexpected oscillations of the IG wave height. However, the time step has a negligible influence on the performance of the implicit scheme combined with the domain decomposition method. Generally, IG sources estimated from the empirical formula method (source M1) and the second-order spectrum method (source M2) perform similarly in reproducing the IG wave height. Regarding the IG frequency spectrum, both the IG sources properly predict the magnitude of the spectral density, but the spectral shapes are not adequately captured. M2 may provide a better directional spread of the IG wave energy. Attention is also paid to the IG waves inside the harbor. The IG waves within the harbor are underestimated, owing to the lack of some mechanisms related to IG waves in the simulation. M1 should be adopted when crudely predicting the magnitude of IG waves inside a harbor. Overall, the unstructured WW3 can effectively predict the coastal IG wave height in southern Sri Lanka, with significant correlation and acceptable errors, when compared with in-situ measurements. Finally, the IG source M1 is refined to remove the erroneous spectral gap between the IG and wind-wave frequency bands in the WW3 spectra when compared to the in-situ observed spectra.

A direct coupled method is established on the basis of the Boussinesq equations and Rankine source method to analyze the responses of floating bodies near islands and reefs. The detailed theoretical derivation, numerical solution method and the relevant calculation program THAFTS-BR are also completed. Then, the motions and connector loads of a three-module VLFS deployed near islands and reefs are investigated based on the model tests and the numerical method. Some useful conclusions are obtained, which can provide a reference for the analysis of dynamic responses, design and construction of the floating bodies near seashores and islands.

The statistical properties of obliquely incident irregular waves over a planar sloping bottom were investigated numerically by the well-known numerical wave model FUNWAVE 2.0. Irregular waves based on the averaged JONSWAP spectra with various wave heights and peak periods were simulated to propagate over planar bottoms. A wide range of incident angles from 0° though 75° were considered to study the influence of incident angles. It was found that incident angles have a significant influence on the wave nonlinearity. The wavelet-based bicoherence revealed that the degree of triad wave interactions of primary waves and the higher harmonics was apparently weakened by increasing wave incident angles. Importantly, using the simulated data, the Klopman wave height distribution was improved by incorporating the influence of obliquely incident angles. It was found that the improved Klopman distribution shows better performance for describing wave height distributions in shallow water depth. Moreover, two empirical formulae are recommended to reflect the relationship between the skewness and the asymmetry of waves and the Ursell number for obliquely incident waves on plane sloping bottoms.

A direct coupled method is established on the basis of the Boussinesq equations and RANKINE source method to analyze the hydroelastic responses of floating bodies near islands and reefs. The detailed theoretical derivation, numerical solution method and the relevant calculation program THAFTS-BR are also completed. A single module VLFS in uniform water depth is then taken as the research object, the accuracy and reliability of the THAFTS-BR program are validated by comparing the hydroelastic responses of VLFS calculated by the popularly-used software THAFTS. Finally, the motions and loads of the VLFS deployed near islands and reefs are investigated based on the model tests and the numerical method. Some useful conclusions are obtained, which can provide a reference for the analysis of dynamic responses, design and construction of the floating bodies near seashores and islands.

In this paper, the problem of linear long-wave scattering by a submerged circular cylinder or a circular pit located in a general idealized bottom topography is considered. Because of the generality of the bottom topography, the problem has various physical and engineering backgrounds. By skillfully using variable transforms, a close-formed analytical solution to the long-wave equation (LWE) in terms of Fourier-cosine series is developed, which finds several existing analytical solutions to be its degenerated cases. Based on the present solution, the influence of various factors, including the convexity or concavity of the bottom topography, the submergence of the circular cylinder or circular pit, and the wavelength of incident waves on wave amplification or attenuation is investigated.

An investigation of the effects of a uniform current strength direction (following or opposing wave propagation) on the nonlinear transformation of irregular waves over a submerged trapezoidal sill is carried out using SWASH, a non-hydrostatic numerical wave model. The nonlinear parameters (i.e., asymmetry, skewness, and kurtosis) are calculated, and the empirical formulas for these parameters are presented as a function of the local Ursell number based on the present numerical data measured. In the shoaling area of the submerged sill, the nonlinear characteristics of waves are more obvious when waves propagate in the same direction as the currents than when waves propagate in the opposite direction. Whereas nonlinear parameters grow with the strengthening of the following currents over the crest, they tend to decrease as the adverse current velocity increases over the crest area of the submerged sill.