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The dynamic compressive deformation of frozen soil was investigated by conducting the split-Hopkinson pressure bar (SHPB) experiments at three temperatures and different high strain rates, and the dynamic stress–strain responses and failure modes of the frozen soil were analyzed. The experimental results demonstrate that the frozen soil exhibits evident dependence on the strain rate and temperature under the dynamic loading condition. The dynamic compressive stress–strain curve of the frozen soil was divided into three parts: the linear, nonlinear rising, and strain softening parts. The nonlinear rising and strain softening parts were both caused by the damage attributed to the debonding between the ice particles and soil matrix, from which a rate-dependent damage evolution equation was obtained. Moreover, a damage-coupled dynamic viscoelastic constitutive model of frozen soil at high strain rate was derived. A comparison between the theoretically predicted results and the experimental ones showed that the developed dynamic viscoelastic model could well describe the dynamic mechanical behavior of frozen soil at high strain rate.

This study aimed to explore the clinical value of simulated puncture in percutaneous nephrolithotomy in the treatment of complex kidney stones.A total of 120 patients with complex kidney stones who were treated with percutaneous nephrolithotomy in our hospital between March 2017 and March 2020 were enrolled in this study and randomly divided into two groups: the research group and the control group (n = 60 in each). Each subject underwent a dual-source computed tomography (CT) scan of the pelvis and both kidneys before the operation. The research team imported the CT data into Mimics19 software to create a three-dimensional (3D) reconstruction of the skin, bones, kidneys, collecting system, and stones. Based on the 3D reconstruction model, the target renal calyx to be punctured was determined, the best puncture channel was designed, and puncture was simulated. Data regarding the simulated puncture were imported into 3-Matics11 software; the angle and depth of the puncture were measured, and then these data were used to guide percutaneous nephrolithotomy. 3D reconstruction and simulated puncture were not undertaken for the patients in the control group before the operation. The effects of treatment in the two groups were compared.First-stage percutaneous nephrolithotomy was successfully completed in both groups of patients. The outcome was better in the research group than in the control group in terms of operation time, number of punctures required for successful establishment of a percutaneous renal channel, number of percutaneous kidney puncture channels, and intraoperative blood loss, and the differences were statistically significant (p0.05 for all). The stone clearance rate was higher in the research group than in the control group, but the difference was not statistically significant (p = 0.471). The incidence of penetrating kidney injury was lower in the research group than in the control group, but the difference was not statistically significant (p = 0.154).For patients due to undergo percutaneous nephrolithotomy for the treatment of complex kidney stones, preoperative simulated puncture helps to improve the puncture accuracy and to reduce the number of punctures required for successful establishment of a percutaneous renal channel, the number of puncture channels, the operation time, and the blood loss, and therefore it is worth promoting.

Excessive zinc (Zn) uptake is toxic to both plants and animals. 24-Epibrassinolide (EBL), a plant steroid hormone, plays a pivotal role in regulating plant resistance to various stresses. In this s...

The effects of foliar application of 24-epibrassinolide (EBR) on chlorophyll content, oxidative damage, and antioxidant capacity in eggplant (Solanum melongena L.) seedlings during a short-term chilling stress and subsequent recovery were investigated. The eggplant seedlings pretreated with 0.1 μM EBR were exposed to 5 °C for 12 h in the dark and then recovered under a normal temperature for another 12 h. The results show that EBR alleviated a chilling-induced oxidative stress reflected by a decrease in malondialdehyde and H2O2 content, O2 ·− production rate, and an increase in chlorophyll content and activities of superoxide dismutase, guaicol peroxidase, and catalase. The EBR pretreatment also promoted activities of ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, as well as the accumulation of ascorbic acid (AsA) and glutathione (GSH) involved in the AsA-GSH cycle. Moreover, after the12 h recovery, EBR plus chilling treated leaves showed no significant changes in content of MDA and chlorophyll a, lower reactive oxygen species (ROS) content, and greater activities of AsA-GSH cycle enzymes than in seedlings only chilled. The results suggest that EBR alleviated an oxidative damage caused by the dark chilling stress and accelerated a recovery rate mainly through increasing the ROS scavenging system including the AsA-GSH cycle.

SummaryBrassinosteroids (BRs) have been implicated in the responses of plants to various environmental stresses.To explore the mechanism(s) of BRs in the tolerance of plants to low temperatures, 24-epibrassinolide (EBR)-induced changes in chlorophyll concentrations, gas exchange parameters, chlorophyll fluorescence, and anti-oxidant defence systems in eggplant (Solanum melongena L.) were studied under chilling stress conditions. Seedlings were exposed to 10°C/5°C (day/night) chilling temperatures for 8 d, with or without a single spray of 0.1 ?M EBR applied 24 h beforehand.The EBR treatment partially overcame the inhibition of growth caused by 8 d of chilling stress.The application of EBR to chilled seedlings had a significant effect on photosynthesis, as reflected by increases in the concentrations of chlorophyll a, chlorophyll b, and total chlorophyll, the net photosynthetic rate (Pn), stomatal conductance (gs), the quantum efficiency of PSII (Fv/Fm), the efficiency of the excitation capture of open PSI...

In this paper, the carburising process of steel foil was simulated by numerical method and the carbon transfer coefficient β at the workpiece surface was calculated with the conventional formula for the steel foil carburising test. The results indicated that foil thickness, carburising time and carbon diffusion coefficient in foil apparently affect the calculated carbon transfer coefficient, which always has a smaller value than the preset β value (the true value) and decreases with decreasing carbon diffusion coefficient. This paper suggests that the conventional formula is applicable only when carbon diffusion coefficient in foil is close to infinity; otherwise, the calculated β has obvious error and consequently, gives false information about the influences of other test factors. We propose a new calculation method based on the analytical solution of the diffusion equation during steel foil carburising and a supplementary test, with which the calculated β coefficient is close to the true value,...

This study was carried out to understand the mechanism of protection of plants under cold stress by exogenous 24-epibrassinolide (EBR). The eggplant (Solanum melongena L.) seedlings were pretreated with five concentrations of EBR (0, 0.05, 0.1, 0.2 and 0.4 °M) and then exposed to day/night temperatures of 10/5 °C for 8 d. The results show that EBR, especially 0.1 °M EBR, dramatically alleviated growth suppression and a decrease in chlorophyll content and photosynthetic rate caused by the cold stress. In addition, EBR also decreased malondialdehyde content and O2·− production rate induced by the cold stress, and increased the activities of superoxide dismutase, guaiacol peroxidase, catalase, and ascorbate peroxidase, and proline content. The results of the present study suggest that exogenous EBR could improve cold tolerance of eggplant by regulating photosynthesis and antioxidative systems.

Electroforming has been applied in the fabrication of a mold. However, its lower microhardness has prevented its wider usage in general plastics and optical mold making. In this paper, CeO2 nanoparticles is first added to the bath to improve the microhardness of the electroformed microprism mold. Compared with microprism pure nickel mold, the microhardness and the wear resistance of the microprism Ni-CeO2 nanocomposite mold were significantly improved. The maximum microhardness of 530HV was observed in the nanocomposite deposits obtained at the current density of 1 Adm−2, and the microhardness of pure nickel is approximately 291HV. Finally, a microprism Ni-CeO2 nanocomposite mold was successfully electroformed.

The improvement of the incorporated nanoparticle content in nanocomposite coatings is a key factor in composite electrodeposition. This paper describes a modified sediment co-deposition (SCD) technique which has been developed to produce Ni–CeO2 nanocomposite coatings, with the aim of enhancing the embedded CeO2 nanoparticle content. The maximum content of CeO2 particles in the nanocomposite coatings created using this modified SCD technique is 7·09 wt-%, which is the highest reported. A maximum microhardness of 630 HV is obtained, which is significantly greater than that observed in nanocomposite coatings fabricated using the conventional electrodeposition technique. As the wear resistance of the nanocomposite coatings increases with increasing incorporated CeO2 nanoparticle content, so this nanocomposite coating with an incorporated CeO2 nanoparticle content of 7·09 wt-% exhibits maximum wear resistance.

Electroforming is applied to fabricate microprism moulds, however only low working current density is employed because the higher current density at the edge limits the usable value of the working current density. Reduction of current density at the edge is a key in the enhancement of the working current density. In this paper, a secondary cathode was introduced to lower the edge current density. By this technique, the edge current density of the primary cathode surface is not only weakened obviously but can be even lower than that of the others. In addition, a high electrolyte flow rate has been introduced to improve working current density. Experimental results show that both the microhardness and tensile strength of the electroformed layer increase with electrolyte flowrate. By using both secondary cathode and high speed electrolyte flow, the electroforming time could be reduced significantly and mechanical properties of the electroformed layer are not adversely affected in electroforming of microprism...

The effects of exogenous 24-epibrassinolide (EBR) on the growth, oxidative damage, antioxidant system and ion contents in eggplant (Solanum melongena L.) seedlings under salt stress were investigated. Eggplant seedlings were exposed to 90 mM NaCl with 0, 0.025, 0.05, 0.10 and 0.20 mg dm−3 EBR for 10 d. EBR, especially at concentration 0.05 mg dm−3, alleviated growth suppression caused by NaCl stress, decreased electrolyte leakage, superoxide production and content of malondialdehyde and H2O2 in NaCl-treated plants. EBR also increased activities of superoxide dismutase, guaiacol peroxidase, catalase and ascorbate peroxidase and the contents of ascorbic acid and reduced glutathione. Furthermore, we also found that Na+, Cl− contents were decreased, K+, Ca2+ contents and K+/Na+, Ca2+/Na+ ratios were increased in the presence of EBR under salt stress.

Impurity scattering in a superconductor may serve as an important probe for the nature of superconducting pairing state. Here we report the impurity effect on superconducting transition temperature $T_\mathrm{c}$ in the newly discovered Cr-based superconductor K$_2$Cr$_3$As$_3$. The resistivity measurements show that the crystals prepared using high-purity Cr metal ($\geq$99.99\%) have an electron mean free path much larger than the superconducting coherence length. For the crystals prepared using impure Cr that contains various \emph{nonmagnetic} impurities, however, the $T_\mathrm{c}$ decreases significantly, in accordance with the generalized Abrikosov-Gor'kov pair-breaking theory. This finding supports a non-$s$-wave superconductivity in K$_2$Cr$_3$As$_3$., Comment: 5 pages, 3 figures, accepted for publication in SCIENCE CHINA Physics, Mechanics & Astronomy

Landslide monitoring is important in predicting the behavior of landslides, thereby ensuring environmental, life, and property safety. On the basis of our previous studies, we conducted the double shear test by using a third-generation optical fiber transducer that uses expandable polystyrene (EPS) as base material. However, the third-generation transducer has poor performance when cohesive force is present between the grout and capillary stainless steel pipe of the transducer. Thus, the fourth-generation optical fiber transducer was invented. Similar to the third-generation transducer, the fourth-generation transducer also used EPS as its base material. Single shear test was conducted on the fourth-generation transducer after being grouted with cement mortar (1:1 mix ratio). The micro-bend loss mechanism of the optical fiber was considered, and the optical time domain reflectometry instrument was used. The fact that the loss sequence of optical fibers subjected to loading is different at various locations is found. The relationship of the loading-point displacement VS. optical fiber sliding distance and optical loss were measured. Results show that the maximum initial measurement precision of the newly proposed device is 1mm, the corresponding sliding distance is 21 mm, and the dynamic range is 0–20 mm. The fourth-generation transducer can measure the movement direction of loadings, thus making this transducer applicable for landslide monitoring.

The microstructure and electromagnetic properties of FeCoB-SiO 2 thin films which were deposited on different substrates (silicon, glass and Mylar) by using magnetron sputtering were studied. X-Ray Diffraction revealed that FeCo nanocrystalline only precipitated in FeCoB-SiO 2 thin films on silicon and glass substrates, and the FeCoB-SiO 2 films on Mylar substrate were amorphous. The surface images obtained by atomic microscopy (AFM) indicated that films on Mylar substrate with biggest particle size (about 120–150 nm), and agglomerated particle was discovered. The static electromagnetic properties, including resistivity and saturation magnetization for the films on different substrates, had also been investigated. The films sputtered on glass showed highest resistivity (2140 μΩcm) and a biggest saturation magnetization (4πMs = 13 kG).

We investigate superconductivity and transport properties of Co doped SmFe$_{1-x}$Co$_{x}$AsO system. The antiferromagnetic (AFM) spin-density wave (SDW) order is rapidly suppressed by Co doping, and superconductivity emerges as $x$ $\geq$ 0.05. $T_c$$^{mid}$ increases with increasing Co content, shows a maximum of 17.2 K at the optimally doping of $x\sim$ 0.10. A phase diagram is derived based on the transport measurements and a dome-like $T_c$ versus $x$ curve is established. Meanwhile we found that the normal state thermopower might consist of two different contributions. One contribution increases gradually with increasing $x$, and the other contribution is abnormally enhanced in the superconducting window 0.05 $\leq$ $x$ $\leq$ 0.20, and shows a dome-like doping dependence. A close correlation between $T_{c}$ and the abnormally enhanced term of thermopower is proposed.

Syndecan-1 belongs to the syndecan family of cell surface transmembrane heparan-sulfate proteoglycans, which participate in cell proliferation, cell migration and cell-matrix interactions. Decreased expression of syndecan-1 has been observed in some gastrointestinal malignancies, and it is thought that high levels of syndecan-1 correlate with the maintenance of epithelial morphology and inhibition of invasiveness. In our study, we characterized the expression of syndecan-1 in normal, chronic pancreatitis and primary and metastatic human pancreatic cancer tissues, in cultured pancreatic cancer cell lines and in esophageal, gastric, colon, and liver cancers. Pancreatic cancer cell lines expressed syndecan-1 mRNA and protein at variable levels. In addition, these cells also released syndecan-1 into the culture medium. Pancreatic cancer tissues markedly over-expressed syndecan-1 mRNA in comparison with both chronic pancreatitis (2.4-fold increase, p0.01) and normal pancreatic samples (10.6-fold increase, p0.01). There was no difference in syndecan-1 mRNA expression between early and advanced tumors. By in situ hybridization and immunohistochemistry, syndecan-1 expression was evident at relatively low levels in the ductal cells and less frequently in acinar cells of the normal pancreas. In chronic pancreatitis, syndecan-1 was present at low to moderate levels in areas with atrophic acinar cells and ductular complexes. In contrast, in pancreatic cancer tissues, syndecan-1 was present at moderate to high levels in the majority of the cancer cells within the tumor mass and also in metastatic lesions of pancreatic tumors. Syndecan-1 mRNA levels in other gastrointestinal malignancies (esophageal, gastric, colon and liver cancers) were not significantly different from the levels observed in the corresponding normal samples. Together, our findings suggest that syndecan-1 expression by pancreatic cancer cells may be of importance in the pathobiology of this disorder and that its role in pancreatic cancer seems to be different from that in other gastrointestinal malignancies.

Binding of nerve growth factor (NGF) to its receptor TrkA leads to intracellular tyrosine kinase activation and regulates the growth and differentiation of various non-neuronal tumours.In the present study NGF and TrkA were analysed by Northern blot analysis, in situ hybridisation and immunohistochemistry in 41 esophageal cancer samples in comparison to normal controls.NGF mRNA (P0.01), but not TrkA mRNA was down-regulated in esophageal cancer samples compared with normal tissues. In the normal esophagus, NGF mRNA and protein was present in epithelial cells of the entire epithelial layer and TrkA mRNA and protein was present in epithelial cells of the basal layer. In esophageal cancer NGF and TrkA mRNA and protein were present in the cancer cells. Down-regulation of NGF correlated with poor differentiation (P0.01) and advanced tumour stage (P0.01). Low TrkA expression was related to advanced tumour stage (P0.05).A loss of activation of the NGF/TrkA pathway occurs during tumour progression and may contribute to loss of tumour differentiation in esophageal cancer.

The crystallization behaviors of the (Ti36.1Zr33.2Ni5.8Be24.9)100−xCux (x = 5, 7, 9, 11, 13, 15, 17; at. %) metallic glasses are investigated under both the continuous heating and isothermal conditions by the differential scanning calorimetry. Quasicrystals are found in the crystallization products under both conditions by X-ray diffraction, transmission electron microscopy, and high-resolution transmission electron microscopy. The evolution of the primary crystallization products of these alloys is discussed in detail. The effects of the increasing distortion energy of the icosahedral short-range order with the increasing Cu content in the(Ti36.1Zr33.2Ni5.8Be24.9)100−xCux (x = 5, 7, 9, 11, 13, 15, 17) alloys are found to be responsible for the evolution of the crystallization products. The isothermal crystallization kinetics deviates from the Johnson-Mehl-Avrami-Kolmogoroff (JMAK) model. A modified JMAK model with an impingement parameter is found to be suitable for the isothermal crystallization kinetic...

The composites of In nanoparticles embedded in Al-based amorphous matrix were synthesized. As the content of In increases, the average size of In nanoparticles increases. The melting behaviors of embedded In nanoparticles were investigated, indicating that the melting temperature is suppressed, and the smaller the size is, the lower the melting temperature is. It is confirmed by comparing the differential scanning calorimetry curves with those of the size distribution. The size dependent melting behaviors of nanoparticles were discussed with the thermodynamic model.

Systematic force-deflection measurements with microcantilevers and a combinatorial-deposition method have been used to investigate the Young’s moduli of amorphous composite FeCo–SiO2 thin films as a function of film composition, with high compositional resolution. It is found that the modulus decreases monotonically with increasing FeCo content. Such a trend can be explained in terms of the metalloid atoms having a significant effect on the Young’s moduli of metal–metalloid composites, which is associated with the strong chemical interaction between the metalloid and themetallic atoms rather than that between the metallic components themselves. This work provides an efficient and effective method to study the moduli of magnetic thin films over a largecomposition coverage, and to compare the relative magnitudes of moduli for differentcompositions at high compositional resolution.

6 cases with natal teeth were found in 11930 live births.5 cases, in which eight natal teeth had been found, also had been followed-up for 38-54 months after birth and five crownless root-like mass were found in 4 cases out of 5 at the site where natal teeth had been extracted at the time of birth. The histological study was made in one natal teeth and one root-like mass.

The structural, magnetic, and transport properties of Mo doping La0.67Sr0.33Mn1−xMoxO3 (x=0–0.04) manganite system have been investigated by x-ray diffraction, scanning electron microscopy, magnetization, and magnetoresistance measurements. The Mo doping in Mn site is found to lower the Curie temperature Tc slightly and induce the cluster spin glass behavior in ferromagnetic state of La0.67Sr0.33MnO3. The room temperature magnetoresistance of Mo doping La0.67Sr0.33Mn1−xMoxO3 is found to be 50% higher than that of La0.67Sr0.33MnO3 without Mo doping. The significant enhancement for room temperature magnetoresistance could likely be attributed to the presence of the cluster spin glass state caused by the Mo doping.

A series of 122 phase BaFe$_{2-x}$Ni$_x$As$_2$ ($x$ = 0, 0.055, 0.096, 0.18, 0.23) single crystals were grown by self flux method and a dome-like Ni doping dependence of superconducting transition temperature is discovered. The transition temperature $T_c^{on}$ reaches a maximum of 20.5 K at $x$ = 0.096, and it drops to below 4 K as $x$ $\geq$ 0.23. The negative thermopower in the normal state indicates that electron-like charge carrier indeed dominates in this system. This Ni-doped system provides another example of superconductivity induced by electron doping in the 122 phase.

Based on Landau-Devonshire model, the bifurcation characteristic of rotor-shape memory alloy bearings(SMAB) system was investigated in this paper. Heteronomous system was transformed into autonomous system in averaging method and Van der Pol transformation, and the existence of Hopf bifurcation was proved in theory. The concept of broadened set of equilibrium point was introduced to improve centre manifold method to be adapted to heteronomous system. The equation of the flow on the centre manifold of rotor-SMAB system was obtained, and the existence of transcritical bifurcation and supercritical pitchfork bifurcation was proved in theory. Finally the results in centre manifold method and averaging method were compared with each other. The comparison shows that the results of the two methods were both the parts of global dynamic characteristic of rotor-SMAB system, while centre manifold method can be applied to research bifurcation behavior in the case of more dimensions. It means that the two methods both have limitation, and global dynamic characteristic must be obtained in kinds of method.

A model of the disturbed magnetic field and disturbed velocity of flux transfer events (FTEs) is deduced on the basis of the vortex-induced reconnection theory. The topology and signatures of FTEs are calculated and discussed. The authors propose that the observed forms of FTE signatures depend on the motional direction of the FTE tube, the positions of the spacecraft relative to the passing FTE tube, and which part of the FTE tube (the magnetosphere part, the magnetopause part, or the magnetosheath part) the spacecraft is passing through. It is found that when a FTE tube moves from south to north along a straight line in the northern hemisphere, positive FTEs appear for most passages; however, reverse FTEs are also observed occasionally while the signatures of B[sub Z] (B[sub L]) appear as a single peak, and the irregular FTEs always correspond to oblique line motions of the FTE tube. The velocity signatures are similar to those of the magnetic field, but in the northern hemisphere their directions are all just opposite to the magnetic field. The calculated results for the magnetic field are compared with 61 observed FTEs. The observed signatures (B[sub N] and B[sub L]) of 52 FTEs are consistentmore » with the calculations. The results indicate that a majority of observed FTEs correspond to passages of spacecraft through the edges of FTE tubes.« less