A Rare Benzothiazole Glucoside as a Derivative of 'Albedo Bluing' Substance in Citrus Fruit and Its Antioxidant Activity.

'Albedo bluing' of fruits occurs in many varieties of citrus, resulting in a significant reduction in their commercial value. We first presented a breakthrough method for successfully extracting and purifying the 'albedo bluing' substance (ABS) from citrus fruits, resulting in the attainment of highly purified ABS. Then, HPLC and UPLC-QTOF-MS were used to prove that ABS in the fruits of three citrus varieties (Citrus reticulate Blanco cv. 'Gonggan', 'Orah', and 'Mashuiju') are identical. However, the chemical structure of ABS remains elusive for many reasons. Fortunately, a more stable derivative of ABS (ABS-D) was successfully obtained. Through various analytical techniques such as HRESIMS, 1D and 2D NMR, and chemical shift calculation, ABS-D was identified as 2,4-dihydroxy-6-(ß-D-glucopyranosyloxy)phenyl(5,6-dihydroxy-7-(ß-D-glucopyranosyloxy)benzo[d]thiazol-2-yl)methanone, indicating that both ABS and its derivative belong to a rare category of benzothiazole glucosides. Furthermore, both ABS and ABS-D demonstrated potent antioxidant abilities. These findings lay the groundwork for further elucidating the chemical structure of ABS and the causative mechanism of the 'albedo bluing' phenomenon in citrus fruits.

Local-Nonlinearity-Enabled Deep Subdiffraction Control of Acoustic Waves.

Diffraction sets a natural limit for the spatial resolution of acoustic wave fields, hindering the generation and recording of object details and manipulation of sound at subwavelength scales. We propose to overcome this physical limit by utilizing nonlinear acoustics. Our findings indicate that, contrary to the commonly utilized cumulative nonlinear effect, it is in fact the local nonlinear effect that is crucial in achieving subdiffraction control of acoustic waves. We theoretically and experimentally demonstrate a deep subwavelength spatial resolution up to λ/38 in the far field at a distance 4.4 times the Rayleigh distance. This Letter represents a new avenue towards deep subdiffraction control of sound, and may have far-reaching impacts on various applications such as acoustic holograms, imaging, communication, and sound zone control.

Analysis of the Potential Angiogenic Mechanisms of BuShenHuoXue Decoction against Osteonecrosis of the Femoral Head Based on Network Pharmacology and Experimental Validation.

OBJECTIVE: Osteonecrosis of the femoral head (ONFH) is a common orthopedic disease with a high disability rate. The clinical effect of BuShenHuoXue decoction (BSHX) for ONFH is satisfactory. We aimed to elucidate the potential angiogenic mechanisms of BSHX in a rat femoral osteonecrosis model and bone marrow mesenchymal stem cells (BMSCs). METHODS: With in vivo experiments, we established the steroid-induced osteonecrosis of the femoral head (SONFH) model using Sprague-Dawley (SD) rats (8-week-old). The rats were randomly divided into five group of 12 rats each and given the corresponding interventions: control, model (gavaged with 0.9% saline), BSHX low-, medium- and high-dose groups (0.132 3, 0.264 6, and 0.529 2 g/mL BSHX solution by gavage). After 12 weeks, haematoxylin and eosin (H&E) staining was preformed to evaluate rat osteonecrosis. the expression of angiogenic factors (CD31, VEGFA, KDR, VWF) in rat femoral head was detected by immunohistochemistry, qPCR and western blotting. In cell experiment, BMSCs were isolated and cultured in the femoral bone marrow cavity of 4-week-old SD rats. BMSCs were randomly divided into eight groups and intervened with different doses of BSHX-containing serum and glucocorticoids: control group (CG); BSHX low-, medium-, and high-dose groups (CG + 0.661 5, 1.323, and 2.646 g/kg BSHX gavage rat serum); dexamethasone (Dex) group; and Dex + BSHX low-, medium-, and high-dose groups (Dex + 0.661 5, 1.323, and 2.646 g/kg BSHX gavaged rat serum), the effects of BSHX-containing serum on the angiogenic capacity of BMSCs were examined by qPCR and Western blotting. A co-culture system of rat aortic endothelial cells (RAOECs) and BMSCs was then established. Migration and angiogenesis of RAOECs were observed using angiogenesis and transwell assay. Identification of potential targets of BSHX against ONFH was obtained using network pharmacology. RESULTS: BSHX upregulated the expression of CD31, VEGFA, KDR, and VWF in rat femoral head samples and BMSCs (p < 0.05, vs. control group or model group). Different concentrations of BSHX-containing serum significantly ameliorated the inhibition of CD31, VEGFA, KDR and VWF expression by high concentrations of Dex. BSHX-containing serum-induced BMSCs promoted the migration and angiogenesis of RAOECs, reversed to some extent the adverse effect of Dex on microangiogenesis in RAOECs, and increased the number of microangiogenic vessels. Furthermore, we identified VEGFA, COL1A1, COL3A1, and SPP1 as important targets of BSHX against ONFH. CONCLUSION: BSHX upregulated the expression of angiogenic factors in the femoral head tissue of ONFH model rats and promoted the angiogenic capacity of rat RAOECs and BMSCs. This study provides an important basis for the use of BSHX for ONFH prevention and treatment.

Diaqua-[µ-11,23-di-tert-butyl-3,7,15,19-tetra-azatricyclo-[19.3.1.1(9,13)]tetra-cosa-1(25),2,6,9,11,13(26),14,19,21,23-do-decaene-25,26-diolato-κ(4)N(3),N(7),O(25),O(26):κ(4)N(15),N(19),O(25),O(26)]dicopper(II) bis-(perchlorate).

In the dinuclear title complex, [Cu(2)(C(30)H(38)N(4)O(2))(H(2)O)(2)](ClO(4))(2), the coordination cation has crystallographically imposed twofold rotational symmetry. The Cu(II) ion is five-coordinated by two N and two O atoms from the macrocylic ligand and one O atom from a water mol-ecule, forming a square-pyramidal N(2)O(3) geometry with the water mol-ecule in the apical position. The distance between the two Cu(II) atoms is 3.0930 (5) Å. Hydrogen bonds between water mol-ecules and between water mol-ecules and perchlorate anions assemble two cations and four anions into discrete supermolecules of S(4) symmetry. Intramolecular O-H⋯N hydrogen bonds are also observed. The perchlorate anion and the tert-butyl group are disordered over two positions, with occupancies of the major positions of 0.527 (11) and 0.592 (9), respectively.

Vibration Energy Harvesting from the Subwavelength Interface State of a Topological Metamaterial Beam.

Topological metamaterial has been a research hotpot in both physics and engineering due to its unique ability of wave manipulation. The topological interface state, which can efficiently and robustly centralize the elastic wave energy, is promising to attain high-performance energy harvesting. Since most of environmental vibration energy is in low frequency range, the interface state is required to be designed at subwavelength range. To this end, this paper developed a topological metamaterial beam with local resonators and studied its energy-harvesting performance. First, the unit cell of this topological metamaterial beam consists of a host beam with two pairs of parasitic beams with tip mass. Then, the band structure and topological features are determined. It is revealed that by tuning the distance between these two pairs of parasitic beams, band inversion where topological features inverse can be obtained. Then, two sub-chains, their design based on two topologically distinct unit cells, are assembled together with a piezoelectric transducer placed at the conjunction, yielding the locally resonant, topological, metamaterial, beam-based piezoelectric energy harvester. After that, its transmittance property and output power were obtained by using the frequency domain analysis of COMSOL Multiphysics. It is clear that the subwavelength interface state is obtained at the band-folding bandgap. Meanwhile, in the interface state, elastic wave energy is successfully centralized at the conjunction. From the response distribution, it is found that the maximum response takes place on the parasitic beam rather than the host beam. Therefore, the piezoelectric transducer is recommended to be placed on the parasitic beam rather than host beam. Finally, the robustness of the topological interface state and its potential advantages on energy harvesting were studied by introducing a local defect. It is clear that in the interface state, the maximum response is always located at the conjunction regardless of the defect degree and location. In other words, the piezoelectric transducer placed at the conjunction can maintain a stable and high-efficiency output power in the interface state, which makes the whole system very reliable in practical implementation.

A Liquid Metal-Enhanced Wearable Thermoelectric Generator.

It is a key challenge to continuously power personal wearable health monitoring systems. This paper reports a novel liquid metal-enhanced wearable thermoelectric generator (LM-WTEG that directly converts body heat into electricity for powering the wearable sensor system. The gallium-based liquid metal alloys with room-temperature melting point (24~30 °C) and high latent heat density (about 500 MJ/m3) are used to design a new flexible finned heat sink, which not only absorbs the heat through the solid-liquid phase change of the LM and enhances the heat release to the ambient air due to its high thermal conduction. The LM finned is integrated with WTEG to present high biaxial flexibility, which could be tightly in contact with the skin. The LM-WTEG could achieve a super high output power density of 275 µW/cm2 for the simulated heat source (37 °C) with the natural convective heat transfer condition. The energy management unit, the multi-parameter sensors (including temperature, humidity, and accelerometer), and Bluetooth module with a total energy consumption of about 65 µW are designed, which are fully powered from LM-WTEG through harvesting body heat.

Efficient and High-Purity Sound Frequency Conversion with a Passive Linear Metasurface.

Despite the significance for wave physics and potential applications, high-efficiency frequency conversion of low-frequency waves cannot be achieved with conventional nonlinearity-based mechanisms with poor mode purity, conversion efficiency, and real-time reconfigurability of the generated harmonic waves in both optics and acoustics. Rotational Doppler effect provides an intuitive paradigm to shifting the frequency in a linear system which, however, needs a spiral-phase change upon the wave propagation. Here a rotating passive linear vortex metasurface is numerically and experimentally presented with close-to-unity mode purity (>93%) and high conversion efficiency (>65%) in audible sound frequency as low as 3000 Hz. The topological charge of the transmitted sound is almost immune from the rotational speed and transmissivity, demonstrating the mechanical robustness and stability in adjusting the high-performance frequency conversion in situ. These features enable the researchers to cascade multiple vortex metasurfaces to further enlarge and diversify the extent of sound frequency conversion, which are experimentally verified. This strategy takes a step further toward the freewheeling sound manipulation at acoustic frequency domain, and may have far-researching impacts in various acoustic communications, signal processing, and contactless detection.

Highly efficient and selective membrane separation of copper from nickel in ammoniacal solution using mixtures of M5640 and BESO as membrane carriers.

Separation of copper from nickel in ammoniacal/ammonium chloride solution using a flat-sheet supported liquid membrane impregnated with mixtures of Acorga M5640 and bis(2-ethylhexyl)sulfoxide (BESO) was investigated. The crucial parameters influencing copper transport and separation abilities of copper and nickel, such as carrier concentration of M5640 and BESO in the membrane phase, initial concentration of ions in the feed phase, H2SO4 concentration in the strip phase and membrane stability, were discussed. The results show that the mixtures of carriers (20 vol% M5640 + 20 vol% BESO) in the membrane have a considerable antagonistic effect on membrane transport of nickel, but favor copper transport. Nearly all of the copper was transferred from the feed phase to the strip phase after 12 hours with a flux of 2.05 × 10-5 mol m-2 s-1 under the following conditions: 100 mg L-1 each of the copper and nickel dissolved in 1.0 mol L-1 each of ammonia and ammonium chloride solution as the feed phase, 60 g L-1 H2SO4 as the strip phase, and stirring speed of 800 rpm in two aqueous phases. Meanwhile less than 3.8% of the nickel was transported into the strip phase over the same time. Copper and nickel were efficiently separated with a calculated factor of 26.3. Furthermore, satisfactory membrane stability was obtained with at least ten cycle runs in this separation system.

Meta-neural-network for real-time and passive deep-learning-based object recognition.

Analyzing scattered wave to recognize object is of fundamental significance in wave physics. Recently-emerged deep learning technique achieved great success in interpreting wave field such as in ultrasound non-destructive testing and disease diagnosis, but conventionally need time-consuming computer postprocessing or bulky-sized diffractive elements. Here we theoretically propose and experimentally demonstrate a purely-passive and small-footprint meta-neural-network for real-time recognizing complicated objects by analyzing acoustic scattering. We prove meta-neural-network mimics a standard neural network despite its compactness, thanks to unique capability of its metamaterial unit-cells (dubbed meta-neurons) to produce deep-subwavelength phase shift as training parameters. The resulting device exhibits the "intelligence" to perform desired tasks with potential to overcome the current limitations, showcased by two distinctive examples of handwritten digit recognition and discerning misaligned orbital-angular-momentum vortices. Our mechanism opens the route to new metamaterial-based deep-learning paradigms and enable conceptual devices automatically analyzing signals, with far-reaching implications for acoustics and related fields.

Enhanced activity and stability of industrial lipases immobilized onto spherelike bacterial cellulose.

This study focused on improving activity and stability of industrial lipases by means of enzymatic immobilization onto spherelike bacterial cellulose (SBC) newly synthesized by a particular bacterial strain (Gluconacetobacter xylinus, JCM 9730). The results revealed that immobilizing lipases onto aldehyde-modified SBC with a size of 6.10±0.50mm could lead to two optimal hydrolytic activities of lipases under both acidic (pH 5) and alkaline conditions (pH 8), which was superior to free lipases that only exhibited an alkaline activity at pH 9. In addition, immobilizing lipases onto SBC could also achieve an improved active temperature below 30°C for lipases, which would help to reduce the energy consumption in the industrial production. Overall, this novel biomaterial has great potential as a green carrier for the immobilization of industrial lipases to enhance the recycling hydrolytic capability of oils and fats in various industrial divisions.