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Two new compounds, dendronobilate (1) and 4-O-demethyl-nobilone (2), together with one known fluorenone were isolated from the aerial parts of Dendrobium nobile Lindl. Their structures were characterized by detailed analysis of 1D and 2D NMR spectra, HRESIMS and ECD spectra. Compounds 1–3 showed significant α-glucosidase inhibitory activity with IC50 values of 27.46 ± 3.14, 4.52 ± 0.33, and 10.78 ± 2.05 μM, respectively, which were superior to the acarbose (745.9 ± 3.3 μM). The binding interactions of 1 and 2 with α-glucosidase were investigated using molecular docking simulations. In addition, compound 2 exhibited potent inhibitory effect on NO production in LPS activated RAW264.7 cells with the IC50 value of 35.40 ± 1.77 μM without cytotoxicity observed.

Herein, a series of 6BaO·1CaO·2Al2O3 + x wt% Sc2O3 (x = 1, 3, 5, 7, 9) impregnants were synthesized by a liquid-phase co-precipitation method and subsequent sintering at 1200 °C. The as-synthesized emissive materials were impregnated into porous tungsten matrices at 1700 °C, and their phase composition and electron emission performance were investigated. The X-ray diffraction analysis of the sintered and melted impregnated products revealed that they comprised multi-phase structures consisting of (Ba,Ca)3Al2O6, Ba2ScAlO5, and BaAl2O4 phases. Furthermore, the addition of 3 wt% Sc2O3 to the impregnated test cathodes significantly increased the emission level of the test cathode to 11.4 ± 0.6 A cm−2 at 1100 °CB (i.e., brightness temperature). The relationship between the electron emission properties and phase concentration in the impregnants was analyzed, and the results revealed that the emission performance of the cathodes deteriorated with an increase in the Sc2O3 content, which could be attributed to an increase in the concentration of non-active BaAl2O4 phase in the impregnants.

Panax notoginseng is an important traditional medicinal plant, but the commercial value is threatened by root-rot disease caused by rhizosphere microbes and a potential health risk caused by plant arsenic (As) accumulation. Whether rhizospheric microbes isolated from P. notoginseng rhizosphere soil could impact As uptake and transport into P. notoginseng is not yet known. Among the three root-rot disease-causing pathogens Fusarium flocciferum (PG 1), Fusarium oxysporum (PG 2), and Fusarium solani (PG 3) and one root-rot disease biocontrol fungus Trichoderma koningiopsis (FC 1) and five biocontrol-exerting bacterial species Bacillus siamensis (BC 1), Delftia acidovorans (BC 2), Brevibacillus formosus (BC 3), Mortierella alpine (BC 4), and Bacillus subtilis (BC 5), one As-resistant pathogen and four biocontrol microorganisms with As-resistant ability were identified. The As-transforming ability of the identified fungi and bacteria was ranked in the order of FC 1 > PG 1 and BC 2 > BC 3 > BC 1, respectively. Then, the As-resistant biocontrol and pathogenic microbes were initiated to colonize the rhizosphere of 1-year-old P. notoginseng seedlings growing in artificially As(V)-contaminated soil to evaluate the impact of microbe inoculation on P. notoginseng As uptake and transport capacity. Concentration of As in P. notoginseng tissues decreased in the order of the sequence stem > root > leaf. Compared to treatment without colonization by microorganism, inoculation with microorganisms increased As root uptake efficiency and root As concentration, especially under treatment of inoculation by BC 2 and PG 1 + BC 2. As transport efficiency from root to stem decreased by inoculation with microorganism, especially under treatment with inoculation of BC 2 and PG 1 + BC 2. However, the impact of microorganism colonization on As stem to leaf transport efficiency was not obvious. In summary, inoculation with rhizosphere microbes may increase As accumulation in P. notoginseng root, especially when using bacteria with high As transformation ability. Therefore, it is necessary to evaluate the As transformation capacity before applying biological control microorganism to the rhizosphere of P. notoginseng.

Three new triterpenoids (1–3), including two new 19 (10 → 9β) abeo-tirucallane derivatives (1–2) and a new tirucallane-type triterpenoid (3), together with two known tirucallane-type triterpenoids (4–5) were isolated from the ethanol extract of the fruits of Chukrasia tabularis. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopic analyses and MS data. The isolated triterpenoids 1 and 2 exhibited anti-inflammatory activities with IC50 values of 75.98 ± 2.12 and 24.86 ± 1.16 μM, respectively. Compound 5 showed cytotoxic activities against the selected tumor cell lines.

Two new 2-(2-phenethyl)chromone derivatives were isolated from agarwood of Aquilaria walla, including a dimeric 2-(2-phenethyl)chromone (1) and a flavonoid-2-(2-phenethyl)chromone (2). Their structures were established based on spectroscopic methods including HRESIMS, 1D, and 2D NMR. Compounds 1 and 2 showed cytotoxic activity against five human cancer cell lines with IC50 values ranging from 4.96–44.34 μM.

The failure mechanism of double-trench silicon carbide (SiC) power metal–oxide–semiconductor field-effect transistors (MOSFETs) under single-pulse avalanche stress is verified. Instead of the widely reported burning out failure mechanism for planar-gate devices, double-trench SiC power MOSFETs suffer from a totally different failure mechanism, as they can only endure a much lower maximum single-pulse avalanche energy ( $E_{\mathrm{ as}}$ ). It is found that during the avalanche process, obvious gate leakage current ( $I_{g}$ ) appears, which is resulted from the high impact ionization rate and high electric field along the gate trench bottom oxide interface, especially the trench corners. The $I_{g}$ continuously grows along with the increase in the peak load current ( $I_{\mathrm{ peak}}$ ), eventually leading to the breakdown of the trench bottom gate oxide under avalanche status. By increasing the value of gate resistor ( $R_{g}$ ), the $I_{g}$ raises the gate–source voltage ( $V_{\mathrm{ gs}}$ ) during the avalanche process, forcing the channel region in an inversion state. Part of the avalanche current is then diverted into the forward conductive current, changing the failure mode from breakdown of the gate oxide to burning out of the entire device. Moreover, the influence of different avalanche stress conditions, including the di / dt and the ambient temperature ( $T_{a}$ ), on the single-pulse avalanche endurance capability of double-trench SiC power MOSFETs is investigated. All the samples express a similar failure phenomenon. The higher the di / dt is, the shorter the avalanche time the device can endure. This is because the higher $I_{\mathrm {peak}}$ results in a higher $I_{g}$ during the avalanche process, leading to early failure of the gate oxide. However, the $T_{a}$ rarely influences the $E_{\mathrm{ as}}$ of the device, indicating that the single-pulse avalanche-induced failure of double-trench SiC power MOSFETs has little business with the melting of the lattice or package, demonstrating the correctness of the failure mechanism proposed in this article.

In this paper, we address the problem of shot-level video summarization, which aims at selecting a subset of video shots as a summary to represent the original video contents compactly and completely. Most existing methods rely on various network architectures to learn a single score predictor for shot ranking and selection. Different from these methods, we plug network feature learning into a binary neural tree to consider multi-path predictions for each shot, thus enabling the shot evaluation from different aspects. Due to the hierarchical structure of the tree, video shots can be coarse-to-fine encoded by imposing self-attention on them along branches, leading to favorable predictions. Extensive experiments were conducted on two real-world datasets, and the results reveal that the proposed method achieves superior performance in comparison with previous state-of-the-art methods.

This work investigates the flow structures of a precessing jet in an axisymmetric chamber with expansion ratio $$D/d=5$$ and length-to-diameter ratio $$L/D=2.75$$ at Reynolds number $${\mathrm{Re}}_{d}=2.4\times 10$$ 4 by use of planar particle image velocimetry. Time-averaged and statistical results indicate that the precessing jet flow is symmetric, on average, in the streamwise plane. Large velocity fluctuations and vorticity exist in the inner and outer shear layers. In addition, vorticity is found in the boundary layer of the chamber wall, due to backflow and confinement. Subsequent correlative analysis indicates that coherent structures are mainly distributed in the shear layer and decay with its development. The results also indicate that precession occurs in the region $$x/d>5$$ and may lead to changes in the structure and position of the shear layer. Further spectral analysis shows that a low-frequency structure with $$\mathrm{St}\approx 7.4\times 10$$ −3, which can be interpreted as precession, exists in the flow field and that the corresponding dominant frequency decreases as the fluid flows downstream. Finally, proper orthogonal decomposition (POD) analysis reveals the most energetic mode representing the flow structure of precession, which has the highest proportion of the total downstream energy. The precession induces an alternating flow, switching between outflow from one side of the chamber and inflow from another side. In addition, four typical instances of flow structures of precession with different intensities or phases are presented through low-order reconstruction of the specified POD modes. These cases show that due to the instability of the reattachment point, the mainstream oscillates up and down in the region near the nozzle exit and twists back and forth in the region near the chamber exit, with changes of scale and position of flow structures on the measurement plane, exposing complex behavior of the instantaneous flow field of precession.

A new polychiral bisabolane sesquiterpene, bisabolanoic acid A (1), was isolated from the mangrove-derived fungus Colletotrichum sp. SCSIO KcB3-2. Its planar structure was identified on the basis o...

Humidity of proton exchange membrane fuel cell, a critical underlying variable that affects stack efficiency and durability, is quite challenging to be well controlled due to the measuring difficulty and multiple couplings with other variables. For precise humidity description and control, this paper utilizes the internal water content as the feedback signal, whose dynamic model is developed by taking into account various auxiliary couplings. Based on the mechanistic model, the dynamic responses of the internal water content are exhibited and analyzed by manipulating the external current, air compressor voltage and humidifier electrical power, respectively. It is shown that the internal water content is able to better describe the real humidity environment, in contrast with the conventional method using cathode inlet relative humidity. Furthermore, a combined feed-forward and feedback control structure is proposed to maintain the internal humidity as close to the desired as possible. Simulation results show that the proposed control method is able to maintain the fuel cell operating within the safe and efficient region, and the humidification power consumption can be reduced because of the precise and less conservative description on the internal humidity.

(Ba,Ca)2ScAlO5 compounds are synthesized and improved emission performance is achieved by virtue of their single-phase structure and low work function. The substitution of Ca2+ for Ba2+ effectively lowers the melting points of (Ba,Ca)2ScAlO5 from over 1800 °C–1700 °C when the Ca2+ substitution reaches 20 at%. During sintering, the co-precipitation precursor first reacts to form (Ba,Ca)3Al2O6 near 912 °C before reacting with BaCO3 and Sc2O3 at the higher temperature of 1186 °C to generate (Ba,Ca)2ScAlO5. Emission tests reveal that the maximum full space charge current density is 9.6 A cm−2 at 1000 °CB (brightness temperature) for the cathode impregnated with single-phase (Ba,Ca)2ScAlO5. Low work function (~1.5 eV) and good emission uniformity make such a cathode promising for applications in high-power microwave devices.

Two new 2-(2-phenylethyl)chromone derivatives (1–2) were isolated from the ethyl acetate extract of artificial agarwood induced by holing method originating from Aquilaria sinensis (Lour.) Gilg, and they were isolated from this genus for the first time. The structures of these two new compounds were elucidated by extensive spectroscopic analyses, including UV, IR, one- and two-dimensional NMR and HRESIMS measurements. Bioassay tests of these two new compounds showed compounds 1 and 2 had weak inhibitory activity against acetylcholinesterase at a concentration of 50.0 μg/ml.

A picrotoxane-type sesquiterpene, dendroterpene E (1), together with five benzene derivatives (2-6), were isolated from the stems of Dendrobium nobile Lindl. Their structures were elucidated by spectroscopic analysis and X-ray diffraction analysis. Compound 1 was a new picrotoxane-type sesquiterpene with a C-9/C-1/O/C-11 oxetane ring, which was first encountered in this type of compounds. Compounds 1-3 exhibited inhibitory activities against α-glycosidase.

Two new coordination polymers (CPs), [Zn(npba)2] (1) and [Cd(npba)2] (2), have been hydrothermally synthesized from Zn(NO3)2·6H2O/Cd(NO3)2·6H2O and 3-nitro-5-(pyridin-3-yl) benzoic acid (Hnpba). The products have been characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, and single-crystal X-ray diffraction. In CP 1, the four-coordinated Zn(II) centers are bridged by npba ligands to generate chains, which are connected through arene π–π stacking interactions to generate a layer structure. In CP 2, the six-coordinated Cd(II) centers are also bridged by npba ligands to form chains with similar connectivity. The photoluminescence properties of CPs 1 and 2 were studied.

Breast cancer is the most common cancer in women worldwide. Due to the heterogeneous nature of breast cancer, the optimal treatment and expected response for each patient may not necessarily be universal. Molecular imaging techniques could play an important role in the early detection and targeted therapy evaluation of breast cancer. This review focuses on the development of peptides labeled with SPECT and PET radionuclides for breast cancer imaging. We summarized the current status of radiolabeled peptides for different receptors in breast cancer. The characteristics of radionuclides and major techniques for peptide labeling are also briefly discussed.

Problematic fouling along with wetting of membrane represent the main barriers for large-scale application of this technology. To solve the above problems and reinforce the anti-pollution and anti-wetting features of the distilling membrane, a brand-new TiO2 nanorods and 1H,1H,2H,2H-perfluorodecylsilane-triethoxy (PDTS) modified alumina hollow ceramic membrane with superhydrophobic surface and self-cleaning property was prepared for utilization in the vacuum membrane distillation. To synthesize the novel membrane, a seed layer was supported on the hollow ceramic membrane by the immersion-calcination method. Then, the TiO2 nanorods were grown on the membrane by hydrothermal method and annealed to strengthen the crystal structure. Finally, the nanorod-grown membrane was immersed in an alcohol solution of PDTS for hydrophobic treatment. The resulted modified membrane was applied to the distillation process to treat 100 g L−1 of concentrated brine for 3 h. It was revealed that the modified membrane possessed with a lower ionic conductivity under 20 µs.cm−1 of the permeated liquid and desirable surface superhydrophobicity at appropriate water contact angle of 152°, thus showing great promise for use in the membrane distillation process.

Technological miniaturization has enabled the development of small satellites weighing as little as 1 kg. Unfortunately, there is still a lack of suitable efficient micropropulsion systems at these scales. The pulsed plasma thruster is a structurally simple form of electric propulsion. This simplicity also makes it ideally suited for miniaturization. Its history can be traced back to applications in satellites that are much larger than micro/nano-satellites. The vast majority of modern pulsed plasma thrusters use solid polytetrafluoroethylene (PTFE) as a propellant. Unfortunately, at lower discharge energy levels such as those necessitated by the power limitations of micro/nano-satellites, PTFE has a tendency to exhibit carbon deposition, which can ultimately lead to thruster failure. In this new era of small satellites, it is important to consider alternative propellants in the miniaturization of pulsed plasma thrusters. This brief review discusses the needs and limitations of small satellites and alternative propellants that may be able to meet these needs. Such propellants may be able to offer advantages such as a longer thruster lifetime, a higher specific impulse, or a higher thrust-to-power ratio. This would enable the development of different types of pulsed plasma thrusters that can be tailored towards specific mission requirements.

Two new compounds named epipaxilline (1) and penerpene J (2) were isolated from the marine-derived fungus Penicillium sp. KFD28. Their structures including absolute configurations were determined o...

This study describes the synthesis, structure, and photophysical properties of a new luminescent polyaromatic boronic acid scaffold, diazaboryl-naphthyl-ketones (DNKs). These stable compounds display extremely bright fluorescence, aggregation-induced emission, positive solvatochromism, and solid-state fluorescence. DFT calculations and X-ray crystallographic study revealed notable electronic and structural differences between these compounds and the parent diaminonaphthalene (DAN) adducts. Acylation of the DAN system causes a localization of both HOMO and LUMO onto the DNK unit, which validates the negligible influence of the B-aryl substituent. The LUMO energy is lowered, and its shape significantly altered. Photophysical data in solution and the solid state revealed blue-shifted, narrowed, and intense emissions for DNKs (up to 89 % quantum yield). The potential utility of the fluorogenic DNK system was demonstrated with a proof-of-concept for the determination of trace boronic acid contaminants in solid samples, down to one-ppm level, using HPLC with fluorescence detection. This method could be useful in pharmaceutical development for the quantitation of difficult-to-detect and potentially mutagenic residual boronic acid from late cross-coupling reactions in drug syntheses.

A two-ligand system composed of the predesigned multivalent and complementary terpyridine-based ligands was exploited to construct heteroleptic metallo-supramolecules and to investigate the self-assembly mechanism. Molecular stellation of the trimeric hexagon [Cd

The application of metal-organic frameworks (MOFs) as SERS-active platforms in multiplex volatile organic compounds (VOCs) detection is still unexplored. Herein, we demonstrate that MIL-100 (Fe) serves as an ideal SERS substrate for the detection of VOCs. The limit of detection (LOD) of MIL-100(Fe) for toluene sensing can reach 2.5 ppm, and can be even further decreased to 0.48 ppb level when "hot spots" in between Au nanoparticles are employed onto MIL-100 (Fe) substrate, resulting in an enhancement factor of 1010 . Additionally, we show that MIL-100(Fe) substrate has a unique "sensor array" property allowing multiplex VOCs detection, with great modifiability and expandability by doping with foreign metal elements. Finally, the MIL-100(Fe) platform is utilized to simultaneously detect the different gaseous indicators of lung cancer with a ppm detection limit, demonstrating its high potential for early diagnosis of lung cancer in vivo.

During the detection of industrial hazardous gases, like formaldehyde (HCHO), the selectivity is still a challenging issue. Herein, an alternative HCHO chemosensor that based on the tin oxide nanoparticles is proposed, which was obtained through a facile hydrothermal method. Gas sensing performances showed that the optimal working temperature located at only 180 °C, the response value of 79 via 50 ppm HCHO was much higher than that of 35 at 230 °C. However, the compromised test temperature was selected as 230 °C, taking into account the faster response/recovery speeds than 180 °C, named 20/23versus 53/60 s, respectively. The response (35) of the SnO2 nanoparticles-based sensor to 50 ppm of HCHO is about 400% higher than that of bulk SnO2 sensor (9), especially when the gas concentration is 1 ppm, SnO2 nanoparticles also has a higher sensitivity which may possibly result from more exposed active sites and small size effect for nanoparticles than for bulk ones. The gas sensor based on SnO2 nanoparticles can be utilized as a promising candidate for practical low-temperature detectors of HCHO due to its higher gas response, excellent response–recovery properties, and perfect selectivity.

Four eudesmane sesquiterpene glycosides named pulisignoside A (1), B (2), C (3), and D (4) were isolated in addition to lemmonin C (5) from the Tibetan folk medicine Ming·chen·serpo (Pulicaria insignis Drumm. ex Dunn). Structures of these compounds were elucidated by comprehensive analyses of MS, 1D NMR, and 2D NMR spectroscopic data. In the anti-nematodal bioassays, pulisignoside C (3) showed nematocidal activity against Meloidogyne incognita (IC50 25.42 ± 0.28 μM).

The unexpected resistance reduction effect of double-trench SiC MOSFETs under repetitive avalanche stress is investigated in this work. After enduring repetitive avalanche stress, the ON-state drain-source resistance (Rdson) of the device decreases. With the help of TCAD simulations, the dominant mechanism is proved to be the injection of positive charges into the gate trench bottom oxide, which is almost irreversible under zero-voltage bias condition at room temperature. For the injected positive charges attract extra electrons just beneath the gate trench bottom, where the carriers pass through under ON state, the resistivity there is reduced, improving the conduction capability of the device. Moreover, an optimization method is proposed. Since the impact ionization rate (I.I.) and the vertical oxide electric field (E⊥) along the gate trench bottom oxide interface contribute to the injection of positive charges, it is recommended to make the bottom oxide thicker to suppress this effect.

In this work we have successfully prepared two lead-doped titanium-oxo clusters with core structures that resemble isolated perovskite PbTiO3 species. In the obtained highly symmetric Pb8 Ti7 -oxo cluster, the central TiO6 octahedra are orthogonally extended to adjacent octahedra through corner-sharing and the eight dopant lead ions form a cubic arrangement, making it the first molecular model of perovskite PbTiO3 . Moreover, the clusters readily dissolved in chloroform and showed high solution stability, as confirmed by MALDI-TOF MS measurements. Based on such solution processability, they can be easily spin-coated to form homogeneous films, which were employed as electron-transport materials in perovskite solar cells to give an average power conversion efficiency of around 15 % and improved device stability. This newly developed bottom-up cluster assembly method provides an efficient approach to the construction of atomically precise models of perovskite metal oxides as well as potential molecular tools to extend their applications.

Accurate and efficient gas monitoring is still a challenge because the existing sensing techniques mostly lack specific identification of gases or hardly meet the requirement of real-time readout. Herein, we present a strategy of conductometric response-triggered surface-enhanced Raman spectroscopy (SERS) for such gas monitoring, via designing and using ultrathin oxide-wrapped plasmonic metal nanoparticles (NPs). The oxide wrapping layer can interact with and capture target gaseous molecules and produce the conductometric response, while the plasmonic metal NPs possess strong SERS activity. In this strategy, the conductometric gas sensing is performed throughout the whole monitoring process, and once a conductometric response is generated, it will trigger SERS measurements, which can accurately recognize molecules and hence realize gas monitoring. The feasibility of this strategy has been demonstrated via using ultrathin SnO2 layer-wrapped Au NP films to monitor gaseous 2-phenylethanethiol molecules. It has been shown that the monitoring is rapid, accurate, and quantifiable. There exist optimal values of working temperature and SnO2 layer thickness, which are about 100 °C and 2.5 nm, respectively, for monitoring gaseous 2-phenylethanethiol. The monitoring signal intensity has a linear relation with the gas concentration in the range from 1 to 100 ppm on a logarithmic scale. Furthermore, the monitoring limits are at the ppm level for some typical gases, such as 2-phenylethanethiol, cyclohexanethiol, 1-dodecanethiol, and toluene. This study establishes the conductometric response-triggered SERS, which enables accurate gas recognition and real-time monitoring.

Since systolic pulmonary arterial pressure (SPAP) is an important diagnostic indicator for various cardiovascular diseases, it is of great significance to determine scientific SPAP reference value in clinical application. However, the SPAP reference values currently have not been applied under a unified standard, and its formulation does not consider the impacts from geographical environment which has proved to be closely associated with SPAP. This study aims to quantify the impacts of geographical factors on SPAP and formulate scientific SPAP reference values, thereby providing support for more accurate diagnosis. Measured SPAP values of 4550 healthy adults were collected from 88 cities across China, and 11 geographical factors were selected. Four geographical factors with significant impacts on SPAP were determined via correlation analysis, including two positive factors (altitude, soil organic matter) and two negative ones (longitude, annual average temperature). Then partial least-squares regression analysis (PLSR) and trend surface analysis were applied to establish predictive models. Through model test using both collected and simulated SPAP data of control points, the PLSR model was determined to have better prediction accuracy and was selected as optimal model to calculate the SPAP reference values of 2322 cities in China. The predictive results ranged from 22.09 to 31.77 mmHg. Finally, hotspot analysis and kriging interpolation method were applied to explore the spatial distribution of SPAP reference values. The result of spatial analysis shows that SPAP reference values of Chinese adults decreased gradually from the West to East in China. This study indicated the significant impacts of geographical environment on SPAP and established predictive model for determining SPAP reference values, which is expected to help enhance clinical diagnostic accuracy.

Image localization is an important supplement to GPS-based methods, especially in indoor scenes. Traditional methods depending on image retrieval or structure from motion (SfM) techniques either suffer from low accuracy or even fail to work due to the texture-less or repetitive indoor surfaces. With the development of range sensors, 3D colourless maps are easily constructed in indoor scenes. How to utilize such a 3D colourless map to improve single image localization performance is a timely but unsolved research problem. In this paper, we present a new approach to addressing this problem by inferring the 3D geometry from a single image with an initial 6DOF pose estimated by a neural network based method. In contrast to previous methods that rely multiple overlapping images or videos to generate sparse point clouds, our new approach can produce dense point cloud from only a single image. We achieve this through estimating the depth map of the input image and performing geometry matching in the 3D space. We have developed a novel depth estimation method by utilizing both the 3D map and RGB images where we use the RGB image to estimate a dense depth map and use the 3D map to guide the depth estimation. We will show that our new method significantly outperforms current RGB image based depth estimation methods for both indoor and outdoor datasets. We also show that utilizing the depth map predicted by the new method for single indoor image localization can improve both position and orientation localization accuracy over state-of-the-art methods.

A novel confined nitride (SiN) charge trapping 3-D NAND flash with excellent postcycling retention performances was demonstrated. Using a uniform sidewall lateral recess in the 3-D stack followed by a SiN pull-back process to isolate the SiN trapping layer in a self-aligned way is critical to facilitate this structure. Lower erase saturation ${Z}$ -direction. Therefore, this structure is in favor of the larger memory window (>10 V) design. Random telegraph noise (RTN) characteristics are comparable to the traditional 3-D NAND device with 100 years at 60 °C and even longer at room temperature. Moreover, superior post-1K-cycled multilevel cell (MLC) retention was also illustrated, which even sustains 150 °C and one-week baking. Therefore, the device has the potential to meet the low-cost long-retention archive memory applications.

A new sterol, named 6β-methoxyergosta-7,9(11),22E-triene-3β,5α-diol (1), together with seven known ones (2–8), was isolated from the fruiting bodies of Haddowia longipes. Their structures were identified on the basis of 1D and 2D NMR spectroscopy as well as MS. The inhibitory activity of these isolates against acetylcholinesterase (AChE) showed that compound 1 exhibited weak inhibitory activity.

In this work, titanium-capped cobalt clathrochelates have been applied as secondary building units (SBUs) for the construction of supramolecular rings. Two heterometallic wheel-like [Ti6Co12] complexes based on cobalt clathrochelates, [C6H15N4]2[TiCo2(μ2-Oipr)(Oipr)2(Dmg)3]6 (2, Dmg = dimethylglyoxime) and H6[TiCo2(μ2-Oipr)(Oipr)2(Dmg)3]6 (3), have been successfully synthesized and characterized. The supramolecular stacking modes of these wheels are largely dependent on the applied synthetic conditions, which further impact their gas adsorption properties.

Two new cyclic diarylheptanoids, casuaritriol A (1) and casuaritriol B (2), were isolated from the EtOAc extract of litters (including branches and leaves) of Casuarina equisetifolia, along with a new triterpene casuariene (3), and two known compounds diarylheptanoids adanin (4) and ostryopsitriol (5). Their structures were elucidated by spectroscopic analysis (including HRESIMS, 1D NMR and 2D NMR data), and the absolute configuration of 3 was determined by analysis of the ECD data according to the octant rule. Compound 1 exhibited inhibitory activity against α-glycosidase with inhibition rate of 45.1 ± 1.4 % at a concentration of 500 μg/mL. In addition, compound 4 showed weak inhibitory activity against acetyl cholinesterase (AChE) with inhibition rate of 14.9 ± 1.1 % at a concentration of 50 μg/mL.

This study investigates self-sustained oscillation of the flow in a double-cavity channel with cavity length–width ratio L/H = 3 using a time-resolved particle image velocimetry (TR-PIV) technique. Three Reynolds numbers based on the cavity length L and the bulk velocity in the narrow section of the channel $$U_{0}$$, i.e., $$Re_{L}$$ = 12,500, 24,580, and 49,100, are considered to investigate the influence of Reynolds number on the self-sustained oscillation. As the Reynolds number increases, the oscillation becomes more intense and shifts to the leading edge of the double-cavity channel. However, the power spectra and contour plots of the spatial v–v correlation coefficient reveal that the periodicity of the oscillation becomes less profound as the Reynolds number increases. A further phase-averaged analysis reveals the spatiotemporal evolution process of oscillation and convincingly demonstrates a more intense and complicated process of the oscillation as the Reynolds number increases.

During the course of searching for structurally interesting and bioactive compounds, a further chemical investigation of the leaves of Heynea trijuga Roxburgh was performed, which led to the isolation of a new ergostane derivative, named 3β, 4β, 20S-trihydroxyergosta-5, 24(28)-dien-16-one (1), together with five known sterides (3β, 23S)-ergosta-5, 24(28)-diene-3, 23-diol (2), ergosta-5, 24(28)-diene-3β-diol (3), stigmast-5-ene-3β, 7α-diol (4), sitoindoside I (5) and stigmast-3β, 5α, 6β-triol (6). The structure of the new compound was elucidated using a combination of 1 D, 2 D NMR techniques and HR-EI-MS analyses. All the compounds were evaluated for cytotoxic activity against tumor cell line BEL-7402 by MTT method.

Travel time estimation (TTE) on a specific route is a challenging task since the complex road network structure and hard-captured temporal patterns. Many excellent methods have been proposed to address the aforementioned problems. Some approaches well designed heuristically in a non-learning based way have the advantage of a quick response to the query for travel time estimation. However, these methods are largely affected by the noise of traffic data since they are limited to a single feature. Existing road segment based methods are generally considered intuitive but are not accurate enough for they fail to model complex factors, like delay and direction of intersections. In this paper, we propose a novel attention based sequence learning model for travel time estimation of a path (ASTTE), that not only considers the real-world road network topology as multi-relational data but also refine the problem to the road segment and intersection direction aspects. Besides, we integrate the traffic information as local and neighbor dependency, which helps to monitor dynamic traffic conditions during the trip. The use of the attention mechanism allows the model to focus on significant elements among the path comprises road segments and intersections. High-quality experiments on two real-world datasets have demonstrated the effectiveness and robustness of our framework.

Deep neural networks are capable of learning powerful representation, but often limited by heavy network architectures and high computational cost. Knowledge distillation (KD) is one of the effective ways to perform model compression and inference acceleration. But the final student models remain parameter redundancy. To tackle these issues, we propose a novel approach, called Variational Bayesian Group-level Sparsification for Knowledge Distillation (VBGS-KD), to distill a large teacher network into a small and sparse student network while preserving accuracy. We impose the sparsity-inducing prior on the groups of parameters in the student model, and introduce the variational Bayesian approximation to learn structural sparseness, which can effectively prune most part of weights. The prune threshold is learned during training without extra fine-tuning. The proposed method can learn the robust student networks thathave achieved satisifying accuracy and compact sizes compared with the state-of-the-arts methods. We have validated our method on the MNIST and CIFAR-10 datasets, observing 90.3% sparsity with 0.19% accuracy boosting in MNIST. Extensive experiments on the CIFAR-10 dataset demonstrate the efficiency of the proposed approach.

Seven new quinazoline-containing indole alkaloids (1-7) named aspertoryadins A-G, along with nine known ones (8-16), were isolated from the marine-derived fungus Aspergillus sp. HNMF114 from the bivalve mollusk Sanguinolaria chinensis. The structures of the new compounds were elucidated from spectroscopic data, X-ray diffraction analysis, ECD spectra analysis, and ECD calculations. Compound 1 bears an aminosulfonyl group in the structure, which is rarely encountered in natural products. Compounds 6, 7, and 13 exhibited quorum sensing inhibitory activity against Chromobacterium violaceum CV026 with MIC values of 32, 32, and 16 μg/well, respectively.

Two new alkaloids (1–2), and four known ones (3–6) were isolated from branches of Cephalotaxus hainanensis Li. The structures of new alkaloids were elucidated by extensive analysis of HRESIMS, 1D and 2D NMR data. The absolute configuration of compound 2 was established on the basis of experimental and computed ECD data. All compounds were evaluated for their cytotoxic activity against K562, BEL-7402, SGC-7901, A549, and Hela human cancer cell lines. Compound 6 exhibited significant activity with IC50 values ranging from 4.86 to 26.56 μM, respectively.

The chromatographic elution process is a key step in the production of notoginseng total saponins. Due to quality variability of loading samples and resin capacity decreasing over cycle time, saponins, especially the five main saponins of notoginseng total saponins, need to be monitored in real time during the elution process. In this study, convolutional neural networks, one of the most popular deep learning methods, were used to develop quantitative calibration models based on in-line near-infrared spectroscopy for notoginsenoside R1 , ginsenosides Rg1 , Re, Rb1 and Rd, and their sum concentration, with root mean square error of prediction values of 0.87, 2.76, 0.60, 1.57, 0.28, and 4.99 mg/mL, respectively. Partial least squares calibration models were also developed for model performance comparison. Results show predicted concentration profiles outputted by both the convolutional neural network models and partial least squares models show agreements with the real trends defined by reference measurements, and can be used for elution process monitoring and endpoint determination. To the best of our knowledge, this is the first reported case study of combining convolutional neural networks and in-line near-infrared spectroscopy for monitoring of the chromatographic elution process in commercial production of botanical drug products.

Vehicular traffic between different Origin-Destination (OD) pairs for a typical hourly period may statistically correlate with each other. The covariance mainly generated from the daily variation of travel patterns, network topology, and trip chaining activities of household members can be particularly high during the morning peak hour. With the increasing attention on the OD demand variance and covariance in stochastic road networks, a new criterion is proposed in this paper for measuring the estimation accuracy of OD demand covariance. The mathematical properties of this proposed criterion are analyzed to better understand the relationship between the estimation errors of mean and covariance of OD demands. This paper aims to investigate how to optimize the traffic count locations for minimizing the weighted maximum deviation of estimated mean and covariance of OD demands from the “true” values. To consider the effects of stochastic OD demands on the traffic count location problem in the proposed model, link choice proportions are regarded as stochastic variables and updated by an adapted traffic flow simulator in this study. Both the weighted-sum approach and bi-objective approach are examined with the adaption of the firefly algorithm (FA) to solve the single-objective and bi-objective problems. Numerical examples are presented to demonstrate the effects, with and without considering the covariance of the OD demands for the optimization of traffic count locations.

Three new 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones and one new dimeric 2-(2-phenylethyl)chromone were isolated from the agarwood of Aquilaria crassna Pierre ex Lecomte in Laos. The structures ...

An analytical model for the textured infinitely long slider is developed to study the influence of cross-hatched texture on hydrodynamic lubrication by considering the mass-conserving boundary condition. The three-dimensional morphology of the cross-hatched texture is characterized by a series of mathematical formulas. By using multigrid method and Gauss–Seidel iteration, the hydrodynamic pressure distribution of textured surface can be obtained to analyze the influence of width, depth, spacing, cross-hatched angle and overlapping coefficient of the cross-hatched texture on the hydrodynamic lubrication. The results show that hydrodynamic lubrication can be generated between two parallel plane surfaces with cross-hatched texture. Moreover, the geometrical parameters of the cross-hatched texture have prominent effect on hydrodynamic pressure distribution and load carrying capacity.

PurposeStencil cleaning is an important operation in solder paste printing process. Frequent cleaning may interrupt printing process and increase idle time, as well as loss for performing cleaning. This paper aims to propose a method to optimize the stencil cleaning time and reduce unnecessary cleaning operations and losses.Design/methodology/approachThis paper uses a discrete-time, discrete-state homogeneous Markov chain to model the stencil printing performance degradation process, and the quality loss during the stencil printing process is estimated based on this degradation model. A stencil cleaning decision model based on renewal reward theorem is established, and the optimal cleaning time is obtained through a balance between quality loss and the loss on idle time.FindingsA stencil cleaning decision model for solder paste printing is established, and numerical simulation results show that there exists an optimal stencil cleaning time which minimizes the long-term loss.Originality/valueStencil cleaning control is very important for solder paste printing. However, there are very few studies focusing on stencil cleaning control. This research contributes to developing a model to optimize the stencil cleaning time in solder paste printing process.

Smart fluid manipulation with automatically controlled paper valves will enable automated and multi-step immunoassays on paper-based microfluidic devices. In this work, we present an integrated paper-based microfluidic platform with shape-memory polymer (SMP)-actuated fluid valves capable of automated colorimetric enzyme-linked immunosorbent assays (ELISAs). A single-layer microfluidic paper-based analytical device (μPAD) was designed to store all the reagents on the chip, and sequentially transfer reagents to a paper test zone following a specific ELISA protocol through automatic fluidic flow control by the multiple SMP-actuated valves. The actuation of a paper valve was based on the thermally responsive, duel-state shape transformation of a SMP sheet attached to the root of a paper cantilever beam for driving a hydrophilic paper bridge to connect and disconnect two paper channels. A portable colorimetric reader was developed to control the on-chip valve operations, quantify the colorimetric signal output, display the assay result, and wirelessly transmit the data to a smart phone for the application of telemedicine. Reliable operations of the paper valve and the entire μPAD were demonstrated with success rates of 97% and 93%, respectively. A detection mechanism for valve malfunction was designed and confirmed effective to identify any mal-operation of individual valves, thus rendering our platform reliable in real assays. For device calibration, we conducted direct ELISAs of rabbit IgG in phosphate-buffered saline (PBS), and achieved a low limit of detection (LOD) of 27 pM (comparable to that of standard and paper-based ELISAs). In order to demonstrate the clinical application of our multi-step immunoassay platform, we also conducted sandwich ELISAs to quantify the protein level of an inflammatory cytokine, namely tumor necrosis factor (TNF)-α, in surgically injured laryngeal tissues of rats. The protein levels of TNF-α were shown similar between the conventional and μPAD ELISAs., Microfluidics: Paper valves open doors to new designs Researchers in Canada have improved the design of paper-based analytical devices by developing paper valves which make it possible to carry out fully-automated multi-step analyses. Previous efforts to incorporate valves have been based on electromagnets or compressed sponges, making them too cumbersome or complicated for reliable use in paper-based analytical devices. To overcome this, a team led by Xinyu Liu of the University of Toronto turned to polymers that reversibly change shape in response to temperature. They combined these with a heating element to produce thermally-activated paper valves. Test devices designed to carry out a multi-step ELISA analysis produced results comparable to a standard commercial ELISA kit. The valve design can be used to create devices for other multi-step diagnostic assays which can be used in contexts where lab equipment and skilled personnel are unavailable.

Five new indole-terpenoids named penerpenes E-I (1-5), along with seven known ones (6-12), were isolated from the marine-derived fungus Penicillium sp. KFD28 from a bivalve mollusk, Meretrix lusoria. The structures of the new compounds were elucidated from spectroscopic data and ECD spectroscopic analyses. Compound 1 was assigned as an indole-diterpenoid with a unique 6/5/5/6/6/5/5 heptacyclic ring system. Compound 2 represents an indole-diterpenoid with a new carbon skeleton derived from paxilline by the loss of three carbons (C-23/24/25). Compound 3 contains an additional oxygen atom between C-21 and C-22 compared to paxilline to form an unusual 6/5/5/6/6/7 hexacyclic ring system bearing a 1,3-dioxepane ring, which is rarely encountered in natural products. Compounds 1, 2, 4, and 6 showed inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) with IC50 values of 14, 27, 23, and 13 μM, respectively.

The effects of air, hydrogen, and CO 2 and O 2 mixture sintering atmospheres on the structure, micromorphology, electron emission capability and environmental stability of 612 type barium-calcium-aluminates have been investigated. Both the 6BaO-1CaO-2Al 2 O 3 aluminates sintered in air and hydrogen crystallize in the Ba 3 CaAl 2 O 7 phase. However, the aluminates with the same composition sintered in CO 2 and O 2 mixture crystallizes in the Ba 3 Al 2 O 6 phase with a small amount of BaCO 3 reactant. The microstructure for the aluminates sintered in air and H 2 show similar features while the sample sintered in CO 2 and O 2 mixture atmosphere shows better conglomeration. Emissivity tests indicate that the divergent current density J div for the dispenser cathodes impregnated with aluminates sintering in air, H 2 , and CO 2 and O 2 mixture atmospheres are 6.0, 6.1, and 7.6 A cm −2 at 1130 °C B , respectively. Finally, environmental stability tests indicate that the aluminates with the Ba 3 CaAl 2 O 6 phase sintered in air as well as hydrogen is more environmentally stable than that with Ba 3 Al 2 O 6 phase sintered in CO 2 and O 2 mixture. The process of sintering 612 aluminate in CO 2 and O 2 mixture is beneficial for superior emissivity on the condition of avoiding exposure to moisture.

SnO2-based materials are helpful to detect low concentration of volatile organic compounds (VOCs), whereas high operating temperatures (≥ 350 °C), poor selectivity and inadequate detection limit of the pristine SnO2 hinder their broader applications. An alternative strategy to address these challenge issues is to adopt porous SnO2 nanotubes (NTs) constructed with ultrathin walls to monitor VOCs. However, inconvenient synthetic routes and low-yield rate of NTs with satisfactory wall thickness restrained the application of SnO2 NTs. Herein, we directly turned SnS2 nanosheets to the porous SnO2 NTs by thermal oxidizing the SnS2 precursor in air. After thermal treatment, high crystallinity and porous hierarchical SnO2 NTs with ultrathin walls were successfully synthesized without any impurities. After decorated with Au nanoparticles (NPs), a strong interaction between the Au NPs and hierarchical SnO2 NTs was witnessed. Compared with those reported SnO2-based materials, hierarchical SnO2 NTs indeed improved the gas sensing properties; particularly, the sensor using Au-SnO2 NTs composite gave the largest sensing magnitude, satisfactory detection limit and high selectivity to acetone at operating temperature of 200 °C. Conclusively, the innovation of transforming SnS2 to the hierarchical SnO2 NTs paves the way to building SnO2 NTs from 2 dimensions ultrathin bricks, and for high performance sensing VOCs.

In our ongoing effort to study the metabolites from agarwood of Aquilaria crassna Pierre ex Lecomte (Thymelaeaceae) produced in Laos, three new 2-(2-phenylethyl)chromone derivatives (1−3) were isolated. Their structures were elucidated by comprehensive spectroscopic analyses, predominantly by 1D and 2D NMR spectroscopic methods, and by comparison with the reported data. Compound 2 exhibited tyrosinase inhibitory activity with IC50 value of 172.6 ± 1.7 μM (kojic acid as the positive control, 46.1 ± 1.3 μM) and its inhibition mode was clarified by molecular modelling study. None of the isolates showed significant cytotoxicity towards tested cancer cell lines.

A facile and general strategy is presented for homogenous and ultrathin metal sulfide wrapping on plasmonic metal (PM) nanoparticles (NPs) based on a thiourea-induced isotropic shell growth. This strategy is typically implemented just via adding the thiourea into pre-formed PM colloidal solutions containing target metal ions. The validity of this strategy is demonstrated by taking the wrapped NPs with Au core and CuS shell or Au@CuS NPs as an example. They are successfully fabricated via adding the thiourea and Cu2+ solutions into pre-formed Au NP colloidal solution. The CuS shell layer is highly homogenous (

Images with intensity inhomogeneity pose significant challenges in image segmentation. Local region-based level set models have recently been recognized as promising methods to segment such images. In these models, local intensity information in a neighborhood of predetermined size is extracted and then embedded into the energy functional, guiding the evolution of deformable contour toward desired boundaries. The local neighborhood intensities are assumed to be rather constant; therefore, the selection of neighborhood size greatly influences effectiveness and robustness. Complex image characteristics, such as variation in degree of intensity inhomogeneity and noise levels among regions, can lead to severe challenges for accurate image segmentation when using only a fixed scale parameter for local regions. We propose a new multi-scale local feature-based level set method for image segmentation with an improved strategy based on previous studies of multi-scale image filtering methods, which allow for automatic selection of filtering scale parameters. Our novel method can adaptively determine the optimal scale parameter for each pixel during contour evolution, alleviating the challenges caused by severe intensity inhomogeneity. First, we define a Local Maximum Description Difference feature (LMDD), based on multi-scale local region descriptors. We incorporate the LMDD, associated with the maximum response of multi-scale high-pass filters for each pixel, into three local region based level set models with Chan-Vese (CV)-like structure to construct the energy functional. Finally, we complete the segmentation through minimization of this energy. Our experimental results illustrate the good performance of the proposed level set method for segmenting images with severe intensity inhomogeneity.