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The outer steel tube in a concrete-filled steel tubular (CFST) column confines the core concrete and improves the compressive strength of the core concrete. When there is a notch damage in the tube, the confinement effect may be affected. The confinement effects of the notched steel tube in rectangular CFST columns were systematically investigated by using numerical approaches. Refined three-dimensional finite element models with advanced concrete constitutive relations were established. With the verified finite element modeling method, full-sized square CFST columns with horizontal, vertical, or diagonal notches at different locations of the steel tube were simulated. Stress distributions and deformation modes of the steel tube and core concrete were analyzed. Columns with a horizontal notch at the plate center location displayed a higher axial strength reduction than those with vertical notches. A parametric study was performed to investigate the influences of concrete strengths, steel strengths, steel ratios, notch length to column width ratios, and notch angles on the compressive strengths of the rectangular CFST columns. A practical design formula was proposed based on the obtained results. The proposed formula could effectively predict the influences of different notches on the confinement effect in the notched CFST columns.

To understand the weathering mechanism of sandstone statues in Southwest China, the sandstone of Niche of Sakyamuni Entering Nirvana at Dazu Rock Carvings was sampled. The three experiments were set up, including dry–wet cycle, freeze–thaw cycle and acid rain cycle. In this study, the mass, surface hardness, P-wave velocity were applied to explore the sandstone weathering degree over multiple cycles (for a total of 100 periods, 700 days). Various devices (i.e., X-ray diffraction, scanning electron microscope) were adopted to analyse the sandstone weathering mechanism. The experimental results showed that the deteriorated features of samples were the granular disintegration under the different experimental conditions, and the samples showed a decreased trend as a whole in the mass, surface hardness and P-wave velocity with the increase of periods. The sandstone deterioration by water occurred from the surface to the inner, and it was more serious with the increase of periods. The deterioration degrees affecting the granular disintegration of sandstone followed this order: acid rain cycle, freeze–thaw cycle, dry–wet cycle. Notably, higher H+, concentrations would enhance the sandstone deterioration. The sandstone of the bedding development was more easily to form the granular disintegration. The sandstone experienced the granular disintegration due to the combined effects of the internal factors (i.e., the dissolution of calcite, alteration of feldspar and water swelling and drying shrinkage of smectite on account of moisture) and external factors (i.e., the acid rain, temperature and humidity). The findings could provide useful insights for the protection of the studied statues, and the corresponding theories and methods had important guiding significance for the protection of grottoes in Southwest China.

In this study, we focused on the antioxidant activities in NRK52e cells, a rat renal proximal tubular cell line, of five new phenylpropanoid glycosides, paulowninosides B–F (Compounds 1–5), which were isolated from the n-BuOH soluble part of the 50 % acetone-H2O extract of the flowers of Paulownia fortunei. The structures of the compounds were determined by extensive spectroscopic analyses (UV and IR spectroscopy, HR-ESI-MS, 1D-, 2D-NMR). The levels of antioxidant activities of the compounds were determined by real-time cell analysis (RTCA) of NRK52e cells that underwent H2O2-induced oxidative injury. Compounds 1, 3 and 5 exhibited excellent antioxidant activities compared with control group.

Using dynamic load identification technology to identify the wheel-rail force of rail vehicles is an economical and convenient method for indirect measurement. In this paper an analytical load iden...

A new C13-norisoprenoid, chaenomelesterpenoid C (1), was isolated from the fruits of Chaenomeles sinensis (Dum.Cours.) Koehne together with a known compound, linarionoside C (2). The structure of compound 1 was determined by NMR and MS analysis. Meanwhile, the protective effects of the compounds were tested against corticosterone-induced damage in PC-12 cells using real time cellular analysis (RTCA). Compounds 1 and 2 significantly improved cell viability in corticosterone-induced damaged PC-12 cells with EC50 values of 21.0 and 49.1 μM, respectively.

Some of the largest and best-preserved Buddhist art treasure houses in the world, namely the Mogao Grottoes, are located at the northwest edge of the region of the Qinghai-Tibet plateau and are adjacent to the Altun and Qilian mountains, where the geotectonic activity is intense and large earthquakes have occurred. Future earthquakes are one of the major threats to the caves of the Mogao Grottoes; therefore, it is important that their dynamic performance is studied when an earthquake occurs. To understand the dynamic performance of the densely distributed caves under the effect of earthquakes, as well as the long-term stability of the Mogao Grottoes, the stress distribution, deformation characteristics, and peak-acceleration amplification factor were analysed under rare-earthquake conditions using a finite-difference element. The numerical study revealed that the most dangerous state of the caves is the initial time when an earthquake occurs. The obvious tensile stress concentration appeared at the top and the bottom of the caves of the middle floor; the main damage was caused by the shear failure towards the direction of the free face and not by the tensile failure. A large permanent horizontal displacement of the caves occurred after an earthquake, mostly at the densely distributed caves of the middle floor. The acceleration amplification effect of the middle-floor caves was significant; the Fourier amplitudes of the acceleration (which were monitored in all caves) were significantly magnified at the frequencies of 3 ~ 4 Hz and 7 ~ 9 Hz, whereas the Fourier amplitudes of the acceleration which were monitored in the middle-floor caves were almost amplified within the entire frequency range. Although the maximum stress was within the allowed limit and no tensile failure occurred, great permanent inhomogeneous horizontal displacements and large accelerations could have a negative effect on the stability of caves and the preservation of wall paintings. Moreover, it was assumed that the calculation results could serve as a type of guidance and as advice on the preventive protection of the Mogao Grottoes.

This paper summarizes the research on passive safety of rail vehicles from the perspective of Crash Energy Management (CEM) in recent decades, which covers the analysis of main crashworthiness stan...

Being a world-renowned heritage site, the Ming Great Wall, located in Qinghai Province, China, mainly has existed as the form of earthen sites with high historical, artistic, and scientific values. However, exposed under environmental impacts for about 500 years, these sites have been seriously threatened. The study on their damage assessment using reasonable methods is the key premise for further protection work. As there are few studies focused on the damage assessment of earthen sites, especially by using machine learning methods, this study explored to apply the current effective machine learning approaches, namely Support Vector Machine (SVM) and back-propagation (BP) Neural Network, into solving this problem. The authors used two such algorithms by training and testing the existing data of damage assessment results of 18 earthen sites located in Qinghai Province. By comparing experimental results, the prediction effects of SVM are much better than those of BP Neural Network. To test its practicability, Liutun Great Wall was chosen as an engineering case, showing better prediction and reasonable performance of SVM. This research has proved that SVM can be selected as a suitable model to assess the damage levels of earthen sites located in Qinghai Province for their future conservation works.

Since 2006, with the implementation of a series of national research projects in the field of earthen site conservation, the Chinese theoretical foundation and technological conservation system for the protection of earthen sites in arid environments has gradually formed. However, there are some global problems such as an unclear relationship between characteristics of diseases on sites and their existing environment, unclear deterioration mechanisms under multi-field coupling, immature stability control technology under dynamic loading, the poor suitability of protection process quality assessment equipment, and a lack of systematic research on comprehensive protection synergy mechanisms. On the basis of summarizing the research achievements in the field of earthen site conservation in China for more than 30 years, and a large number of practical experiences in earthen site reinforcement engineering, this paper expounds the multi-field coupling characteristics of earthen site construction technology, the climatic environment, and dynamic loading and protection measure activities, clarifies the main characteristics of the protection of earthen sites in China at present, puts forward the key scientific and technical problems existing in the conservation of earthen sites, constructs a picture of the research on the conservation of earthen sites under the action of multi-field coupling, and discusses the protection projects of earthen sites under different environments. We hope the technological system can provide support for the transformation of earthen site conservation from the rescuing conservation stage to the stage of both rescuing and preventive conservation, and move the foundation of earthen site conservation towards the stage of preventive protection.

Epimesatines A-I, nine undescribed prenylated flavonoids, along with ten known analogues, were isolated from the aerial parts of Epimedium sagittatum Maxim. The structures and absolute configurations of epimesatines A-I were determined using a combination of spectroscopic data, Rh

Diabetes mellitus can lead to diabetic kidney disease (DKD), which is a kind of chronic kidney diseases (CKDs). Compared with other renal diseases, DKD deteriorates more rapidly to end-stage renal disease, and the 5-year renal survival rate is about 61%. Therefore, monitoring of progression of DKD is vital for improving the survival rate and quality of life for diabetic patients. However, non-invasive and quantitative diagnostic tools are still lacking currently. It has been reported that the occurrence and development of DKD would lead to the changes of renal microvasculature and perfusion. Recently, ultrasound localization microscopy (ULM) has been demonstrated to break the diffraction limit of ultrasound and obtain the microvasculature morphology and blood flow speed map by localizing and tracking the flowing microbubbles. In this study, ULM was performed on kidneys of DKD rat models and control rats to investigate its feasibility in assessment of DKD in vivo. In addition, conventional clinical inspections (urine and serum tests) and conventional ultrasound imaging (Doppler and contrast-enhanced ultrasound imaging) were performed to verify the successful development of diabetes for DKD group. Statistical differences are observed between the clinical inspections-related parameters (urine and serum), CEUS-related parameters [time to peak (TTP) and area under curve (AUC)], and ULM-related parameter (mean blood flow speed of interlobular arterioles). In conclusion, this study shows the potential of ULM in the assessment of DKD in vivo.

Plane wave (PW) imaging has become a popular ultrafast ultrasound (US) imaging method thanks to its high frame rate. However, PW imaging requires multiple steered transmissions for coherent compounding to improve the image quality, at the cost of decreased imaging frame rate. In this study, a phase constraint (PC) based loss function is proposed to train a deep neural network (DNN) to reconstruct B-mode images from single PW transmission, with quality equivalent to that of compounding with 75 PWs. To demonstrate the effectiveness of PC, the proposed method (U-Net-PC) was compared to the original U-Net without PC. Our preliminary data suggested that the addition of PC is useful for improving the quality of B-mode image and the accuracy of motion tracking. Results from simulations show that the proposed method achieves 9.21%, 15.84%, 61.55% and 18.80% improvements in root mean square errors (RMSEs) for displacement estimation. In vivo experiments show that the proposed method achieves better visual quality and higher peak signal-to-noise ratio (PSNR) (increased by 17.27%) and structural similarity (SSIM) in B-mode image (increased by 20.35%) than original U-Net without PC. These results suggest the superiority of the proposed PC-based loss over original loss function.

Ultrasound localization microscopy (ULM) has been developed to significantly improve the spatial resolution of ultrasound imaging by localizing the microbubbles (MBs). However, owing to the unsatisfactory performance of conventional localization methods in localizing overlapped MBs, low MB concentration is typically required, which leads to a long data-acquisition time. Recently, deep learning (DL)-based localization methods have been proposed to improve the precision and processing speed of localization at high MB concentrations. Because the ground truth of in vivo MB locations is difficult to obtain, labeled training datasets are usually generated by simulations. Considering the differences between the simulated and experimental data, the performance of the trained convolutional neural network (CNN) may not generalize well on experimental data. In this study, a self-supervised learning scheme is proposed to train the CNN directly using experimental data and is evaluated on ex vivo chicken embryo chorioallantoic membrane (CAM) data at high MB concentration. Conventional cross-correlation (CC)-based localization method is used for comparison, and the results show that the proposed method performs much better in localization of high-concentration MBs than the CC-based method. In addition, the proposed method forms a closed loop for neural network training through experimental data and bypasses the requirement for labeled training dataset, which is typically generated using simulations.

The image reconstruction process in medical imaging can be treated as solving an inverse problem. The inverse problem is usually solved using time-consuming iterative algorithms with sparsity or other constraints. Recently, deep neural network (DNN)-based methods have been developed to accelerate the inverse-problem-solving process. However, these methods typically adopt supervised learning scheme, which requires ground truths, or labels of the solutions, for training. In many applications, it would be challenging or even impossible to obtain the ground truth, such as the tissue reflectivity function in ultrasound beamforming. In this study, a general framework based on self-supervised learning (SSL) scheme is proposed to train a DNN to solve the inverse problems. In this way, the measurements can be used as both the inputs and the labels during the training of DNN. The proposed SSL method is applied to four typical linear inverse problems for validation, i.e., plane wave ultrasound and photoacoustic image reconstructions, compressed sensing-based synthetic transmit aperture dataset recovery and deconvolution in ultrasound localization microscopy. Results show that, using the proposed framework, the trained DNN can achieve improved reconstruction accuracy with reduced computational time, compared with conventional methods., Comment: to be published in Proceedings of IEEE IUS 2021

Sparse regularization (SR) techniques solve the inverse problem of beamforming and can reconstruct high-quality ultrasound image from single plane wave (PW) transmission, but with long reconstruction time (~1-5 mins). We previously proposed a self-supervised deep neural network (DNN) beamformer to accelerate the SR-based reconstruction of single PW to ~10 ms (DNN mapping time > 9 ms). However, when coherent compounding is used, the reconstruction time will increase by a factor equal to the number of PWs used. In this study, a new coherent compounding strategy is proposed to reduce the number of DNN mappings in the case of coherent compounding. Using simulation and experimental data, the proposed method is demonstrated to achieve comparable image quality and significantly reduced reconstruction time (from ~750 ms to ~33 ms) with 75 PWs, compared with our previous method.

Synthetic transmit aperture (STA) can achieve very high spatial resolution thanks to its dynamic focusing in both transmit and receive. However, because each element is activated individually and sequentially to transmit a spherical wave, the imaging frame rate is low. In addition, the low transmitted energy leads to low signal-to-noise ratio (SNR) echoes. In our previous study, we proposed to use compressed sensing (CS) algorithm to recover full STA dataset from fewer apodized plane wave (PW) transmissions (CS-STA). In this way, the frame rate and SNR of STA imaging can be significantly improved. However, owing to the iterative nature of CS algorithms, the reconstruction of STA dataset is very time consuming, which hampers its real application. In this study, the minimal $l$ 2 -norm least square method is used to recover the STA dataset with significantly reduced computational time. Simulation shows that the proposed method can achieve ~5×103times acceleration for STA dataset reconstruction, compared with CS-STA. Simulated B-mode images show that the proposed method is capable of achieving higher generalized contrast-to-noise ratios (gCNRs) for anechoic inclusions than STA, with maintained spatial resolution. Simulated strain images show that the proposed method could preserve the phase information of radio-frequency data during the reconstruction, and achieve acceptable quality in strain estimation in noise-free condition.

Thanks to two-way dynamic focusing, synthetic transmit aperture (STA) imaging can obtain images with high spatial resolution. However, STA imaging suffers from low signal-to-noise ratio (SNR) and low frame rate. In our previous study, the array elements were spatially encoded with partial Hadamard matrix to transmit plane wave for higher energy and to reduce the number of transmissions for higher frame rate. Thereafter, a compressed-sensing algorithm (CS-STA) was used for the recovery of full STA dataset. However, CS-STA is time-consuming and may destroy the phase information of radio-frequency (RF) signals. In this study, a self-supervised learning (SSL) method was proposed to recover the STA dataset from the encoded PW transmissions, to both accelerate the reconstruction and better preserve the RF phase information for motion estimation. Phantom experiments show that the proposed method achieves similar resolution and improved contrast, compared with STA. Simulation results demonstrate that the proposed method obtains higher performance in lateral strain estimation than STA and CS-STA, in noisy situation. Moreover, the proposed method significantly reduces the reconstruction time from ~1 hour (CS-STA) to ~10 seconds.

Ultrasound microvascular imaging (UMI) has been developed to visualize microvasculature to reveal the conditions and pathologies of diseases. The key of UMI is extraction of blood flow signals by suppressing tissue clutters and background noise. However, the suppression of noise is unsatisfactory when we only use common clutter filtering methods without additional processing of denoising. Spatiotemporal non-local means (stNLM) filtering method has been used to effectively reject noise in ultrasound localization microscopy. In this study, we implemented stNLM in UMI to better suppress the background noise for improved microvascular visualization using the spatiotemporal discontinuity of noise. For comparison, the proposed stNLM-based UMI method was compared with three methods, i.e., method without NLM filtering (conventional UMI), NLM filtering on power Doppler image (PDI), and NLM filtering in the spatial domain (sNLM) of filtered blood flow RF data. The denoising superiority of the proposed method was validated in a human spinal cord tumor in vivo. Quantitative indexes including contrast-to-noise ratio (CNR) and peak-to-side level (PSL) were calculated. Results show that stNLM-based UMI can achieve nearly 15 dB improvement in CNR and nearly 30 dB improvement in PSL compared with conventional UMI. The proposed stNLM-based UMI has the potential of achieving high-quality UMI.

Studies have shown that the perivascular space (PVS) plays an important role in regulation of cerebrospinal fluid (CSF) flow and elimination of endogenous metabolites, and the fluid dynamics of the PVS is related to certain physiological and pathological conditions. Benefiting from high-frame-rate plane wave imaging and advanced clutter filters, ultrafast power Doppler imaging (uPDI) has been developed to visualize microvessels which are invisible using conventional power Doppler imaging. In this study, we explore the feasibility of uPDI in the detection of PVS by injecting microbubbles (MBs) into the cisterna magna of rats and acquiring the ultrasound data in the sections of cerebral ventricle and common carotid artery. Results showed that aggregation of MBs was observed in the cerebral ventricle, which proved that there is a pathway for the CSF flow between the cisterna magna and the cerebral ventricle. After unilateral ligation of the common carotid artery, region of the PVS became larger than before MBs injection and ligation. It suggests that unilateral ligation of the common carotid artery causes unilateral cerebral ischemia, which leads to influx of CSF with MBs into the PVS and further causes expansion of PVS. In conclusion, this study demonstrates that uPDI can be used in the detection of PVS and has the potential to monitor the hemodynamic of PVS in the pathological conditions.

Recently, the resolution of ultrasound imaging has been dramatically increased using ultrasound localization microscopy (ULM), by localizing the spatially isolated microbubbles (MBs). However, owing to the poor penetration and low signal-to-noise ratio (SNR) of plane wave (PW) imaging, it could be challenging to accurately differentiate the isolated MB signal from the background noise. In this study, we propose to utilize short-lag spatial coherence (SLSC) beamformer to suppress the background noise (including residual tissue clutters and electronic noise) based on the high spatial coherence of MB echo signals. Using in vivo data, the proposed method has effectively suppressed noise and preserved the MB signals. Therefore, the number of falsely-detected MBs was reduced to provide a more robust MB localization for ULM.

Rehmanniae Radix Praeparata is the processed products of the root of Rehmannia glutinosa. It has been used as a Traditional Chinese Medicine for thousands of years, and it has been found to possess widely pharmacological activities. In this study, three new 2,2'-difurylketone derivatives (rehmanniaeketone A-C) and two new chromones [3,8-dihydroxy-2-(2-hydroxyethyl)chromone and 3,8-dihydroxy-2-[(2-O-α-D-galactopyranosyloxy)ethyl]chromone] were isolated from the Rehmanniae Radix Praeparata. Furthermore all of the compounds were subjected to cytotoxic testing against the human lung carcinoma A549 cells. The cytotoxic results showed that rehmanniaeketone B and rehmanniaeketone C exhibited more stronger inhibition effects on the cell activity of A549 cells with the IC50 5.23 μM and 2.05 μM than other compounds. And 3,8-dihydroxy-2-(2-hydroxyethyl)chromone exhibited moderately inhibitory activity with the IC50 61 μM. Rehmanniaeketone A and 3,8-dihydroxy-2-[(2-O-α-D-galactopyranosyloxy]chromone showed no inhibitory effects.

Calcined ginger nut (CGN) has been applied in grouting mortars for anchoring unstable earthen sites, but the lack of scientific research limits its application. In this study, CGN-based grouts admixed with fly ash (F), quartz sand (S), or both are evaluated. To explore the optimal mixture ratios, three types of mixing groups (five proportion gradients in each group) are established. All the grout specimens are buried and maintained outdoors, and their physical (shrinkage rate, density, elastic wave velocity, and permeability) and mechanical properties are continuously examined over 180 days. The solidification processes at different ages are simultaneously observed by means of scanning electron microscopy (SEM) images. The results indicate that the physical properties of grouts are influenced significantly by initial moisture content but then remain steady for approximately 15 days. Quartz sand can effectively reduce the shrinkage rate of grouts as well as adjust their density and permeability, and might be considered as an ideal mixing material for CGN. In the solidification process, grouts are rapidly solidified after the initial hydration reaction, and the carbonation reaction in the later stage constantly improves their mechanical strength, with physical properties kept relatively stable. SEM images show fly ash and quartz sand particles are cemented by CaCO3 crystals. Through comprehensive comparison, the grouts with the mass ratio of CGN and S at 1:1 are found to better satisfy requirements that grouts should be compatible with earthen sites.

Calcined ginger nuts admixed by fly ash and quartz sand (CGN-(F+S)) has been validated to be basically compatible to earthen sites as an anchor grout. Accelerated ageing tests including water stability test, temperature and humidity cycling test, soundness test and alkali resistance test are conducted with the objective to further research the property changes of CGN-(F+S) grout. Density, surface hardness, water penetration capacity, water permeability capacity, soluble salt, scanning electron microscopy (SEM) images and energy dispersive spectrometry (EDS) spectrum of these samples have been tested after accelerated ageing tests. The results show that densities of samples decrease, surface hardness, water penetration capacity and water permeability capacity of samples increase generally. Besides, soluble salt analysis, SEM and EDS results well corroborate the changes. Based on the results it can be concluded that property changes are most serious after temperature and humidity cycling test, followed by water stability, soundness and alkali resistance test in sequence. But in general, CGN-(F+S) still has good durability.

Based on the structures of nicotinic acid and chlorfibrate, a series of new H2S donors were synthesized and their anti-atherosclerosis activities using Ox-LDL RAW 264.6 cells as model were evaluated. The release test showed that all the compounds could release H2S effectively and showed low cytotoxicity. In the bioactivity experiments, compounds 1, 3, 9 and 14 increased the survival rate of HUVEC cells treated by ox-LDL; among four compounds, compounds 1 and 3 displayed higher activity than the others. In the foam cell model, compounds 1 and 3 were found to inhibit the formation of foam cells and significantly reduced the content of TC and FC in foam cells. They had more obvious effects on lipid reduction than those of nicotinic acid and chlorfibrate. In anti-oxidation, compounds 1 and 3 significantly reduced ROS and MDA and increased the expression level of SOD, whereas the precursor compounds, niacin and chlorfibrate had little antioxidant effect. In addition, both compounds also inhibited the inflammatory response in foam cells, with reducing pro-inflammatory factor TNF-α and increasing anti-inflammatory cytokine IL-10. WB assay showed that the tested compounds inhibited the expression levels PI3K, Akt and NF-κb proteins. In conclusion, the compounds as H2S donors could protect HUVEC cells from damage and inhibit the formation of foam cells by inhibiting PI3K/Akt/NF-κb signal pathway. All these suggest the compounds have potential to be candidate for anti-atherosclerosis medicines.

To analyze the tensile properties for the single-strap butt joint of a carbon fiber reinforced composite, a finite element model was established using no. 22 and no. 185 materials based on LS-DYNA with the test data and the theoretical solutions reported by Li et al. Then, the tensile properties influenced by three factors were analyzed, i.e., the connection strength, the failure mode of the composite, and the adhesive stress. The results show that the adhesive interface of 0° stacking can greatly improve the tensile strength and reduce the composite matrix tensile damage. With the increase of the adhesive thickness, the connection strength decreases first and then increases. As for the overlap length, its increase is conductive to the tensile strength but detrimental to the lightweight design. Therefore, these factors should be taken into consideration when designing the joint.

Numerous ancient sandstone grottoes remain in northwest and central China, and weathering issues have significantly influenced their preservation conditions. The dramatic naturally cyclic changes in water content and temperature in the environment have been considered to be the main drivers of the physical weathering that commonly occurs at these archaeological sites. Therefore, comparing and understanding the behaviors of sandstone with different weathering degrees under variable environmental conditions would be helpful for further study on predicting the type, location and extent of deterioration of sandstone relics in a small region (such as the surrounding rock of grottoes). This study examines Cretaceous sandstones with two weathering degrees from Bingling Temple Grottoes, China. Standard thin section photomicrographs provide petrographic and mineralogical data and show that the sandstones have identical lithologies. Three types of specifically designed frost weathering tests are then conducted on the samples. After every six weathering cycles, the weathering processes are suspended, and the corresponding parameters, such as dry weight loss, dry density, effective porosity, porosity, P wave velocity, surface hardness and drilling resistance, are measured. At the end of the weathering cycles, the sample variations in grain size distributions are compared, and statistical tests are performed to show the statistical significance of the results. The results indicate that similar deterioration patterns occur on the samples with two weathering degrees under the same weathering tests. The increase in effective porosity surpasses that of the porosity only when the weathering effect is large enough. Furthermore, sandstone with a high degree of weathering might be more susceptible to changes in the internal pores due to its greater initial interconnectivity. In an open system, physical weathering (frost–thaw and dry–wet cycles) would cause the superficial grain size distributions of different rocks to become relatively uniform. Finally, when exposed to the same weathering process, the decreases in the overall mechanical strength in the two sandstones do not differ significantly, but the loss of superficial strength may be different.

Leaf area index (LAI) is one of the important variables for crop growth monitoring and yield estimating. In this article, the potato LAI was retrieved by several vegetation indices (VIs) and spectral parameters of the continuum removal method (SPCRM) to provide accurate estimates. A comparison of the two methods of retrieving precision was completed. The data source for computing VIs and SPCRM was hyperspectral reflectance data for the life cycle, derived from two potato cultivars, Favorite (early maturing variety) and Yanshu 4 (late maturing variety), through field experiments. Sensitive bands were identified to indicate seven VIs by correlation analysis. Additionally, seven SPCRM were computed. Based on these methods, the potato LAI was retrieved and tested. Meanwhile, a comparison of the retrieving precision was implemented. The results showed that compared with the filtered spectral reflectance and VIs, the correlation between the potato LAI and the continuum removal spectral reflectance and its retrieved SPCRM were higher. The determination coefficients (R2) of the retrieving models of four parameters, the total area (S), the left area (Sl), the right area (Sr) and the depth area ratio (W), derived from the continuum removal method were all above 0.801, and their fitting coefficients (r) were all above 0.868, with the mean relative errors (MRE) all

Ruiqi Xu,1,2 Mengnan Zeng,1,2 Yuanyuan Wu,1,2 Shengchao Wang,1,2 Beibei Zhang,1,2 Jingke Zhang,1,2 Yuxuan Kan,1,2 Benke Li,1,2 Bing Cao,1,2 Xiaoke Zheng,1,2 Weisheng Feng1,2 1School of Pharmacy, Henan University of Traditional Chinese Medicine, Zhengzhou, People’s Republic of China; 2The Engineering and Technology Center for Chinese Medicine Development of Henan Province, Zhengzhou, People’s Republic of ChinaCorrespondence: Xiaoke Zheng; Weisheng FengSchool of Pharmacy, Henan University of Traditional Chinese Medicine, 156 Jinshui East Road, Zhengzhou, 450046, People’s Republic of ChinaTel +86-371-6019-0296Email zhengxk.2006@163.com; fwsh@hactcm.edu.cnPurpose: This research aims to investigate the intervention and mechanism of 50% acetone extract of C. officinalis leaves (SZYY) on melanoma xenografts.Patients and Methods: Tumor size and cardiac function were measured via ultrasound. The accumulation of 2-deoxy-D-glucose (2-DG) in tumor tissue was examined with near-infrared in vivo imaging. Flow cytometry was performed to assess apoptosis and reactive oxygen species (ROS) levels in tumor and immune cells in spleen. The levels of inflammatory cytokines in serum were detected by cytometric bead array. The expression of proliferation-, apoptosis-, and angiogenesis-related proteins in tumor cells was measured to evaluate the underlying mechanisms. Subsequently, the effects of four compounds separated from SZYY on the proliferation and migration of A375 cells and STAT3 signaling were examined. The peak identification and contents of the four components were performed via high-performance liquid chromatography (HPLC). Finally, we evaluated the inhibitory effects of STAT3 overexpression on the cytotoxic activity of four constituents in A375 cells.Results: SZYY inhibited the growth and glycolysis of melanoma xenograft in mice, improved cardiac function, increased the percentages of macrophages, neutrophils, and lymphocytes in spleen, reduced the levels of IL-6, IL-17A, TNF-α, and IFN-γ in serum, promoted apoptosis and oxidative stress in tumor tissues, and inhibited STAT3 phosphorylation and expression of angiogenic factors. Chemical analysis showed that SZYY is rich in loganin, rutin, triohimas C, and triohimas D, which all could restrain the proliferation and migration of A375 cells and inhibit the phosphorylation and nuclear translocation of STAT3. Moreover, STAT3 overexpression could diminish the cytotoxic activity of four compounds on A375 cells.Conclusion: SZYY could exert anti-melanoma effects via inhibiting STAT3 signaling to induce apoptosis and inhibit tumor angiogenesis. Its active ingredients might be loganin, rutin, triohimas C, and triohimas D.Keywords: Cornus officinalis, melanoma, STAT3, apoptosis, angiogenesis

Compressed sensing-based synthetic transmit aperture (CS-STA) was previously proposed to recover the full radio-frequency (RF) channel dataset of synthetic transmit aperture (STA) from that of a smaller number of randomly apodized plane wave (PW) transmissions. In this way, the imaging frame rate (FR) and contrast are improved with maintained spatial resolution, compared with those of STA. Because CS-STA reconstruction is repeated for all receive elements and RF samples (with a high sampling frequency), the recovery of STA dataset in RF domain is time-consuming. In the meantime, a large amount of RF data needs to be transferred and stored, resulting in an increase of system complexity and required memory space. In this study, CS-STA is extended to in-phase/quadrature (IQ) domain (with lower sampling frequency) for the recovery of baseband STA IQ dataset to accelerate the CS-STA reconstruction by reducing the amount of data to be processed. More importantly, CS-STA reconstruction using IQ data is of practical importance, as clinical ultrasound systems typically record baseband IQ signal instead of RF signal. Simulations, phantom and in vivo experiments verify the feasibility of CS-STA in IQ domain for the recovery of STA dataset. More specifically, CS-STA using IQ data achieves similar image quality and appreciably improves reconstruction speed (by ∼3 times) compared with that using RF data. These findings demonstrate that IQ-domain CS-STA is capable of relieving the computational and storage burdens, which may facilitate the implementation of CS-STA in practical ultrasound systems.

This dissertation demonstrates the vitality of nature.Natual beauty can enrich students’life and emotions. It naturally edifies students’temperament, inspires students’revolutionary enthusiasm and cultivates their patriotic thoughts and feelings. Nature can be shown with grandeur, magnificence, and masculine beauty in articles using in teaching Chinese as a second language. The beauty of freshness and softness means that the forms of many strange scenes in nature can deviate from the general rules of balanced, symmetrical and harmonious forms into pure beauty. Nature contains a lot of strange scenery,which brings a profound sense of beauty .So it is important to demonstrate the importance of natural beauty in teaching Chinese.

Objective. Synthetic transmit aperture (STA) ultrasound imaging is well known for ideal focusing in the full field of view. However, it suffers from low signal-to-noise ratio (SNR) and low frame rate, because each transducer element must be activated individually. In our previous study, we encoded all the transducer elements with partial Hadamard matrix and reconstructed the complete STA dataset with compressed sensing (CS) algorithm (CS-STA). As all the elements are activated in each transmission and the number of transmissions is smaller than that of STA, this method can achieve higher SNR and higher frame rate. Its main drawback is the time-consuming CS reconstruction (∼hours). In this study, we propose to accelerate the complete STA dataset reconstruction with minimal l 2-norm least squares method. Approach. Partial Hadamard apodized plane wave (PW) transmissions were performed to acquire the PW dataset. Thereafter, the complete STA dataset can be reconstructed from the PW dataset with minimal l 2-norm least squares method. Due to the orthogonality of partial Hadamard matrix, the minimal l 2-norm least squares solution can be easily calculated. Main results. The proposed method is tested with simulation data and experimental phantom and in-vivo data. The results demonstrate that the proposed method achieves ∼5 × 103 times faster reconstruction speed than CS algorithm. The simulation results demonstrate that the proposed method is capable of achieving the same accuracy as the conventional CS-STA method for the STA dataset reconstruction. The simulations, phantom and in-vivo experiments show that the proposed method is capable of improving the generalized contrast-to-noise ratio (gCNR) and SNR with maintained spatial resolution and fewer transmissions, compared with STA. Significance. In conclusion, the improved image quality and reduced computational time of LS-STA pave the way for its real-time applications in the clinics.

To study the compressive mechanical properties of a new type of brazed aluminum honeycomb plate (BAHP), tensile tests on single- and brazed-cell walls as well as compression tests in the out-of-plane, in-plane longitudinal, and transverse directions were conducted. Compared to the material properties of a traditional glued aluminum honeycomb plate (GAHP), those of the single- and brazed-cell walls of the BAHP are entirely different. Therefore, their characteristics should be considered separately when performing theoretical and simulation analysis. Under out-of-plane compression, the core of the BAHP did not debond, owing to its higher strength than that of the GAHP. In comparison, under in-plane compression in the longitudinal and transverse directions, the load&ndash, displacement characteristics, ultimate load, and failure modes also differed, and there was no large-scale cracking. Considering the characteristics of the BAHP, a strength prediction method was proposed. The simulation results demonstrated that the model built based on the new method was highly consistent with the experimental results. Defects with uneven height and debonding will cause the overall instability, and the degree of defects will influence the strength and instability displacement, which have little impact on the elastic stage. Moreover, the model considering defects is closer to the test results.

A new polyacetylene glucoside, Dendranacetylene A (1), and a known compound 8E-decaene-4,6-diyn-1-O

Ultrasound localization microscopy (ULM) enables unprecedented subwavelength spatial resolution by localizing the ultrasound contrast microbubbles (MBs). In conventional ULM methods, low-concentration MB solutions are used to ensure that the MBs are sufficiently sparse to enable localization of individual MB. This leads to a long data-acquisition time (i.e., microbubble-accumulation time) to accumulate enough MBs events using plane wave (PW) imaging. Considering the continuity of the microvessels and redundancy of MB tracks, in this study, we present a method that leverages deep neural network (DNN) to predict microvasculature using significantly reduced data-acquisition time and achieve quality comparable to that obtained using full data-acquisition time. Phantom experiments show that the proposed method significantly improves the density of localized MBs compared with the conventional method. Besides, in vivo experiments demonstrate that the proposed method is capable of reconstructing ULM images using reduced data-acquisition time with small difference, compared with the conventional method.

Compared with conventional delay-and-sum (DAS) beamforming method, sparse regularization (SR) techniques can reconstruct higher quality ultrasound (US) images from plane wave (PW) transmission. However, these methods suffer from long reconstruction time, owing to the high computational complexity inherently associated with its iterative process. In this work, a deep neural network (DNN) is trained to reconstruct plane wave ultrasound (PWUS) images from RF channel data with significantly reduced computational time. To overcome the lack of gold standard of ideal US images, a self-supervised learning scheme is employed to utilize the RF channel data as both the inputs and the labels during the training process. Using simulation data, the proposed method achieves comparable spatial resolution and 3.2-dB higher CNR, compared with the SR method.

To study the compressive mechanical properties of a new type of brazed aluminum honeycomb plate (BAHP), tensile tests on single- and brazed-cell walls as well as compression tests in the out-of-plane, in-plane longitudinal, and transverse directions were conducted. Compared to the material properties of a traditional glued aluminum honeycomb plate (GAHP), those of the single- and brazed-cell walls of the BAHP are entirely different. Therefore, their characteristics should be considered separately when performing theoretical and simulation analysis. Under out-of-plane compression, the core of the BAHP did not debond, owing to its higher strength than that of the GAHP. In comparison, under in-plane compression in the longitudinal and transverse directions, the load–displacement characteristics, ultimate load, and failure modes also differed, and there was no large-scale cracking. Considering the characteristics of the BAHP, a strength prediction method was proposed. The simulation results demonstrated that the model built based on the new method was highly consistent with the experimental results.

The purpose of this research is to study the influence of aspect ratio and end conditions on the strength and failure mode of remolded soil samples in unconfined compressive strength tests....

A new polyacetylene glucoside, Dendranacetylene A (1), and a known compound 8E-decaene-4,6-diyn-1-O-β-d-glucopyranosyl-(1ʺ→2ʺ)-β-d-glucopyranoside (2) were isolated from the flowers of Dendranthema morifolium (Ramat.) kitam. The chemical structures of these compounds were elucidated by NMR and HR-ESI-MS analysis, and comparing these results with data reported in literatures. Additionally, the anti-inflammatory effects of compounds 1 and 2 were evaluated on RAW264.7 murine macrophage cells induced by lipopolysaccharide (LPS). The two compounds significantly inhibited the NO production in LPS-induced RAW 264.7 murine macrophage cells and exhibited anti-inflammatory effects.

Study on the weathering characteristics of Niche of Sakyamuni Entering Nirvana at Dazu Rock Carvings is the first step of scientific conservation. Based on the in-depth investigation on the weathering characteristics of Niche of Sakyamuni Entering Nirvana, the weathering degree was measured and evaluated by means of the in-situ non-destructive surface hardness test and ultrasonic test. The results reveal that the weathering types of Niche of Sakyamuni Entering Nirvana consist of granular disintegration, salt efflorescence, scaling, blistering, cracking, missing parts, biological colonization, and water seepage. The weathering degree of the head and foot of the statues are higher than that of the chest and abdomen in the horizontal direction, and the weathering degree of the upper parts of the statues and the ground area are higher than that between them in the vertical direction. The results of surface hardness and ultrasonic velocity are in close accordance with the weathering degree of the statues. Sedimentary and structural characteristics of sandstone lay a material foundation for various weathering characteristics and degree. The research results pave the way for condition assessment, intervention decision-making, and preventative conservation of the studied statues.

A series of H2S CO dual-donors [Mn(CO)4CS2NR1R2] was synthesized, and evaluated from toxicity and bioactivity. The CO H2S measuring test showed all the complexes not only released CO, but released H2S. The resulting data of cytotoxicity showed all the complexes had activities against the cell proliferation; among them, complexes 1, 2 and 7 displayed higher activities than the others, and their potencies were close to cis-platinum (DDP); whereas the precursors A1-A22 had almost no activities against all five tumor cell lines and W138 cell line proliferation. It is worth noting that complex 1 displayed the highest activity to MCF-7, complex 2 displayed the highest activity to HePG2, and complex 7 showed selectivity inhibition to both A549 and HeLa. The developmental toxicities of the complex were assessed using zebrafish embryos. The results showed complexes 1 and 2 had effect on the mortality and hatching rate of zebrafish embryos in dose-dependent manner. They caused zebrafish malformations when they were over 10 μM. Meanwhile, they displayed dose-dependent toxicities to larval zebrafish. In the test of bio-activities, complexes 1 and 2 had strong anti-inflammatory activities; they not only down-regulated the expression levels of iNOS and TNF-α, up-regulated the expression of HO-1 and IL-10, but also up-regulated COX-2 levels. In contrast, the precursor compound (A1 or A2) displayed lower anti-inflammatory activity than the corresponding complex, which suggests both the CO and H2S from the complex took synergistic effects in the process of anti-inflammation. In addition, the complex showed antihypertensive effect and myocardial protection. This effect also possibly resulted from this synergistic effect. All these suggest the complexes have potential to be candidate medicines.

Conservation practices employed thus far have proven that single materials cannot suitably protect earthen sites. This study compares the effectiveness of single and composite materials, to explore whether composite materials are potential candidates for use in conservation. Soils from the Great Wall of Yongchang, Gansu Province, China, were treated with five types of materials, namely, inorganic materials, organic products, composite materials composed of organic and inorganic materials in different orders, and ethanol. Changes in the colour, weight, mechanical properties, water resistance, microstructures, and element composition were evaluated after treatment. Better reinforcing effects were obtained by applying an organic material and then using an inorganic material. Results showed that a composite material with reasonable reinforcing sequence can greatly improve the properties of soils; hence, composite materials are promising for use in the protection of cultural relics in the future.

There has been great interest in phytoestrogens, which are polyhydric compounds that are derived from plants and have a structure similar to that of the mammalian steroid hormone 17β-estradiol. The present study examined the estrogenic effects of a new natural uridine derivative, lepidiumuridine A (LA), that was isolated from the seeds ofLepidium apetalum. The structure was clarified and determined via analysis of extensive spectroscopic data interpretation. The activity of LA was investigated by measuring the levels of estradiol (E2), luteinizing hormone (LH), follicle stimulating hormone (FSH), and the uterus growth in mice. The proliferation experiment of MCF-7 breast cancer cells was also conducted. Western blot, in-cell western, and antagonist assays with methyl piperidino-pyrazole (MPP) were used for exploring the mechanism of the effects of LA. The results showed that LA elevated the uterine coefficient, the levels of E2, and FSH significantly. In addition, LA significantly elevated ERαexpression in the uterus and MCF-7 cells. MPP inhibited the proliferation of LA-stimulated MCF-7 cell and ERαexpression in MCF-7 cells. Taken together, LA had an estrogen-like effect, which was mainly mediated by the estrogen receptor ERα.

During the process of archaeological excavation in the regions of Southeast China, collapse of test square usually occurs due to poor site-specific conditions. In this paper, the fast Lagrangian analysis of continua in three dimensions (FLAC3D) is employed to reveal the behaviors of test square. Taking the archaeological works in Liangzhu prehistoric earthen sites as the research background, the paper first introduces the geological setting, excavation procedure and monitoring scheme of the studied test square. Then, the deformation of four sides of the test square is modeled using FLAC3D. By comparison, it shows that the numerical results are consistent with the results from field monitoring. The result suggests that the numerical simulation can be effectively applied to representing the actual behaviors of the test square, which is helpful for determination of excavation scheme and stability evaluation of the test square during archaeological excavation. Keywords: Prehistoric earthen site, Archaeological excavation, Test square behaviors, Field monitoring, Numerical simulations

Historical relics of Jurassic sandstones in southwest China have been subjected to weathering damage. Exfoliation, characterized by the detachment of multiple thin stone layers sub-parallel to the stone surface, is common in sandstone heritage sites. However, its mechanism of action remains poorly understood. In this study, a conceptual model of exfoliation is drawn from the literature and field investigations. To quantitatively determine the exfoliation mechanism, a range of non-destructive field-based methods (surface hardness, water absorption test, roughness, and amplitude of residual spalling layers) and laboratory analyses (scanning electron microscopy (SEM) and X-ray diffraction (XRD)) are adopted as weathering agents for separated detachments. In addition, the grain and pore sizes of weathering products are analyzed using digital image techniques. The results show that the roughness, water absorption coefficient, and pore size in sandstone surfaces increase from the inner layer to the outer layer, and their hardness and grain size decrease, respectively. The proportions of quartz, dolomite, and illite increases from the interior to the exterior, whereas the proportion of feldspar decreases correspondingly. The residual column strip structure derived from feldspar alteration and a mixed montmorillonite-illite mineral layer can be observed in the SEM images. It can be inferred from surviving environmental analysis that comprehensive actions from solar radiation, acid rain attack and capillary rise lead to sandstone exfoliation. In addition, the alteration of feldspar plays an important role during sandstone exfoliation. The results of this study enhance our understanding of the exfoliation of the Jurassic sandstone of the Chongqing Danzishi rock carvings in China.

Three new alkaloids, rehmanalkaloid A-C (1-3), and a new iridoid glycoside, rehmaglutoside L (4), together with nine known compounds, including (8S)-7,8-dihydrogeniposid (5), diglycoside (6), monomelittoside (7), mussaenoside (8), darendoside A (9), syringing (10), phenyl-6-O-β- d -xylopyranosyl-O-β- d -glucopyranoside (11), (7R, 8S)-4,9-dihydroxy-3,3′-dimethoxy-7,8-dihydrobenzofuran-1′-propanalneolignan (12), and trans-liovil (13), were isolated from a 95% EtOH extract of dried roots from Rehmannia glutinosa. Their structures were determined by extensive spectroscopic (UV, IR, HR-ESI–MS, and 1D and 2D NMR) analyses. Additionally, compounds 4-8 (iridoid glycosides) were evaluated for their protective effects on H714444444444444444444466666666669c2 cardiocytes impaired by doxorubicin. Among them, compounds 4-8 exhibited protective effects against DOX-induced cardiotoxicity.

Conventional radar emitter identification methods are faced with intensive noise and complex electromagnetic environment, which degrades the performance. Aiming at the feature extraction and identification at low signal-to-noise ratio (SNR), an improved algorithm is developed for the analysis and identification. First, the approach forms the time-frequency distribution and preprocesses the 2-dimensional image with whitening and normalization operations. Then, convolutional neural network (CNN) is introduced to generate high-level and abstract representations. Next, random vector functional link (RVFL) is trained to promote the fast feature learning. Finally, identification is implemented by picking out the maximum of RVFL output. 6 types of simulated emitters are used to validate the proposed algorithm. Experimental results show that the selected types of radar waveforms with additive Gaussian white noise can reach 85% accuracy when SNR up to −2 dB. Compared with the state-of-the-art techniques in feature extraction and identification, the proposed algorithm outperforms in the robustness and comprehensive performance.