Phytochemical compositions, antioxidant and antimicrobial activities analysis of extracts from <i>Vaccinium bracteatum</i> Thunb. leaves

Vaccinium bracteatum Thunb. is an edible plant, which has been used for many food products and is also a resource of traditional Chinese medicine. In this study, the antioxidant and antimicrobial activities of ethanol extracts from its leaves were investigated. To study the characteristic compositions, twelve compounds of extracts accumulated by the D-101 macroporous adsorption resin (VBE) were identified by HPLC-DAD and HPLC-ESI/MS techniques, including chlorogenic acid and its isomers, and eight flavonoid compounds. The contents of total flavonoids, orientin and isoorientin in the accumulated part were 601.4, 44.7, and 96.1 mg/g, respectively, which were far more than that in the raw materials. Furthermore, the antioxidant activities were estimated by DPPH, ABTS, and FRAP assays, which showed that the high content accompanied with strong antioxidant activities. Besides, compared to the same type of bamboo leaves (AOB), the accumulated part possesses better activities. At the last, the antimicrobial activities of VBE were assessed by a serial two-fold dilution assay, the results showed that it had good antimicrobial activities. Taken together, extracts from Vaccinium bracteaturn Thunb. leaves have better antioxidant activities, which can be used as a natural antioxidant

Machine Learning for Short-Term Prediction of Ship Motion Combined with Wave Input

There is a response relationship between wave and ship motion. Based on the LSTM neural network, the mapping relationship between the wave elevation and ship roll motion is established. The wave elevation and ship motion duration data obtained by the CFD simulation are used to predict ship roll motion with different input data schemes. The results show that the prediction scheme considering the wave elevation input can predict ship roll motion. Compared with the direct prediction scheme based on the roll data input, the prediction scheme considering the wave elevation input factor can greatly improve the prediction accuracy and effective advance prediction time. Different wave elevation data inputs have different prediction effects. The advance prediction duration will increase with the increase in the input wave elevation position and the ship distance. The simultaneous input of multi-point wave elevation greatly increases the amount of data, allowing the trained model to utilize a greater data depth. This not only improves the advance prediction duration of the prediction model, but it also enhances the robustness of the model, making the prediction results more stable

Hazard Assessments of Riverbank Flooding and Backward Flows in Dike-Through Drainage Ditches during Moderate Frequent Flooding Events in the Ningxia Reach of the Upper Yellow River (NRYR)

In this study, the riverbank inundation caused by moderate frequent flooding events (with recurrence periods of less than 20 years), along with the increasingly serious hazards of backward flows in dike-through drainage ditches in the Ningxia Reach of the upper Yellow River (NRYR), were investigated. Then, a comprehensive method for hazard assessment of the floodplains and backward flows in the NRYR was proposed, which fully integrated geographical information systems (GISs), remote sensing (RS), and a digital elevation model (DEM), as well as river dynamics theory. This study first established a one-dimensional unsteady hydrodynamic model for the NRYR. The historical flood hydrology observation from 2012, along with the aerial image measurement data of the study area, were used to calibrate and verify the accuracy of the model. The hazards of riverbank inundation and damages to water affected engineering facilities, as well as the backward flows of dike-through drainage ditches caused by the moderate frequent flooding events, were comprehensively analyzed. Also, this study configured the hazard map and proposed revisions to the flood hazard ranking regime definitions, and discussed the impacts and prevention and control measures of moderate frequent flood damages. The proposed method could effectively meet the hazard analysis demands of the moderate frequent flooding events in the NRYR

Broadband Generation of Polarization-Immune Cloaking via a Hybrid Phase-Change Metasurface

Metasurface-enabled cloaking offers an alternative platform to render scatterers of arbitrary shapes indiscernible. However, specific propagation phases generated by the constituent elements for cloaking are usually valid for a single or few states of polarization (SOP), imposing serious restrictions on their applications in broadband and spin-states manipulation. Moreover, the functionality of a conventional metasurface cloak is locked once fabricated due to the absence of active elements. Here, we propose a hybrid phase-change metasurface carpet cloak consisting of coupled phase-shift elements setting on novel phase-change material of Ge2Sb2Se4Te1 (GSST). By elaborately arranging meta-atoms at either 0 or 90 degrees on the external surface of the hidden targets, the wavefront of its scattered lights can be thoroughly rebuilt for arbitrary SOP exactly as if the incidence is reflected by a flat ground, ensuring the targets&rsquo; escape from polarization-scanning detections. Furthermore, the robustness of phase dispersion of meta-atoms endows the metasurface cloak wideband indiscernibility ranging from 7.55 to 8.35 &micro;m and tolerated incident angles at least within &plusmn;25&deg;. By reversibly switching of the phase states of Ge2Sb2Se4Te1, the stealth function of our design can be turned on and off. The generality of our approach will provide a straightforward platform for polarization-immune cloaking, and may find potential applications in various fields such as electromagnetic camouflage and illusion and so forth

Characterization of the complete mitogenome of the Hongyuan Yak Bos grunniens (Artiodactyla: Bovidae) and its phylogenetic analysis

The Hongyuan breed Yak (Bos grunniens) belongs to a member of t the subfamily Bovinae. We provide a complete mitogenome of B. grunniens and analyze its phylogenetic relationship with other related species. Its mitogenome is a circular molecule with 16,322 bp in size, including 13 protein coding genes, 22 tRNA genes, 2 rRNA genes, and a non-coding control region (D-loop, CR) that are conserved in most Bovidae mitogenomes. The total base composition of the B. grunniens mitogenome is 33.67% A, 27.29% T, 25.84% C, and 13.20% G. The gene composition, structure and the arrangement for B. grunniens are similar to those of most other Bovidae species. Phylogenetic analysis of mitochondrial genomes of 30 close species with Bayesian inference and maximum likelihood based on 13 protein-coding genes indicated that B. grunniens breed Hongyuan is more closely related to B. grunniens breed Qinghai Plateau than to B. grunniens breed Xuedong and B. grunniens breed Maiwa. The complete mitogenome of B. grunniens breed Hongyuan provides a potentially useful resource for further exploration of the taxonomic status and phylogenetic relationships of Bovinae and related species

Wavelength-selective, tunable and switchable plasmonic perfect absorbers based on phase change materials Ge

Nanoscale active devices, such as all-optical modulators and electro-optical transducers, can be implemented in heterostructures that integrate plasmonic nanostructures with functional active materials. Here, we demonstrate control over absorption properties in such a heterostructure by coupling the localized surface plasmon resonance (LSPR) of gold nanoantennas to a phase change material (PCM), Ge2Sb2Te5 (GST). The peak absorption of this hybrid absorber approaches near unity at resonance due to the simultaneous excitations of electric and magnetic resonant modes. Moreover, such a hybrid absorber can realize arbitrary wavelength-selective spectral absorption in the mid-infrared region simply by altering the square nanoantennas side length. By controlling the total power of the incident light, the intermediate phases composed of different proportions of the amorphous and crystalline molecules of the GST can be correspondingly tailored, and thus the absorption can be continuously tuned, which provides a flexible and encouraging way to achieve active features once fabricated. Importantly, by converting GST from the amorphous to crystalline state or vice versa, the hybrid absorber can realize bidirectional switching of “ON” and “OFF” states, with an outperformed modulation depth of 98% (or 95%) and extinction ratio of $-17.15\ \text{dB}$ (or $-12.98\ \text{dB}$ ), respectively, indicating its excellent optical modulation performance. Notably, all the stable and intermediate phases of the GST are stable at room temperature, and therefore no sustained external thermal consumption is needed to maintain a desired absorption band for the hybrid scheme. Additionally, the structure can tolerate a wide range of incident angles as well as show polarization-independent features. With these extraordinary optical responses, the proposed scheme could find potential applications in active photonic devices such as optical modulation, thermal imaging and optical switching