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It is extremely important to predict the growth, aggregation, and coalescence failure of voids during the dynamic tensile fracture of ductile metals. In the present work, we used the finite element—smoothed particle hydrodynamics (FE-SPH) adaptive method to simulate the plate impact of tantalum simultaneously from macro- and meso-scales. For macro simulation results, the spallation phenomena and free-surface velocity were in good agreement with the experimental results, verifying the correctness of the simulation method and material model. Moreover, the free surface velocity profiles simulated by the FE-SPH adaptive method is closer to the experiment than those by the finite element method. According to the magnified details of the damage, we envisaged that the deleted elements are converted to SPH particles to represent the formation of voids. By comparing the porosity, we demonstrated the rationality of this envisagement and determined the fine mesh size to simulate growth, aggregation, and coalescence of actual meso-voids. On this basis, we proposed a void-position tracking method to accurately track the temporal and spatial information of voids. Such information would provide a detailed range of damage and describe the features and macro factors affecting void evolution. In general, the fine mesh FE-SPH method can well predict the damage distribution of spallation simultaneously in macro- and meso-scales, and this simple method has important applications. [ABSTRACT FROM AUTHOR]

Direct bonding is an attractive technique to join material components without the use of intermediate adhesive medium. Usually, the bonding interface can experience high level of residual stress concentration due to entrapped nano-scale particulate contamination. Existing theoretical models are not capable of analyzing such residual stress concentration, since they fail to consider the localized material inhomogeneity formed between the bonding pairs as result of thermal and diffusion processes. This paper proposes a new theoretical model to analyze the residual stress concentration in the bonding interface with the consideration of localized material inhomogeneity. Following the idea of Selvadurai and Singh (Int. J. Fract. 25:69–77, 1984), the nano-scaled particulate contamination induced interfacial defect is simulated as a penny-shaped crack indented by a smooth rigid disc inclusion. This mode I crack-inclusion model is interpreted as a three-part mixed boundary value problem in the theory of elasticity, which is solved by a series expansion technique. Mathematical difficulties associated with modelling arbitrary localized material inhomogeneity are overcome by the use of the General Kelvin Solution (GKS) based method. Exact analytical solutions for the stress intensity factors (SIFs) and resultant force on the inclusion are obtained. Our results show that the inclusion-crack radius ratio and the localized material inhomogeneity can have significance effect on the residual stress concentration at the bonding interface. [ABSTRACT FROM AUTHOR]

To enhance the friction and wear performance of TC4 titanium alloy, micro‐arc oxidation(MAO) coating was fabricated on its surface, which was subsequently sealed with a modified graphene/epoxy resin coating to form a composite coating of micro‐arc oxidation ‐modified graphene/epoxy resin. The friction and wear performance of samples sealed by different methods are analyzed and characterized using a scanning electron microscope, an energy spectrometer, and friction and wear tester. The results indicate that the modified graphene/epoxy resin coating successfully combines with the micro‐arc oxidation coating and fills the pores, thereby enhancing the friction and wear performance of the composite coating. In tribological tests, compared with other samples, this composite coating has a lower friction coefficient and specific wear rate, showing excellent friction and wear performance, and its main wear mechanism is adhesive wear. Therefore, the fabrication of a micro‐arc oxidation ‐modified graphene/epoxy resin composite coating can improve the friction and wear performance of TC4 titanium alloy. [ABSTRACT FROM AUTHOR]

Based on the modeling method of 3D meso‐scale finite element model of plain concrete, a 3D meso‐scale finite element model of reinforced concrete is established considering the interface transition zone between reinforcement frame and mortar, and the reliability of the established meso‐scale finite element model is verified by split Hopkinson pressure bar (SHPB) test results. The failure process of reinforced concrete specimens under typical impact velocity and the influence of interface effect on specimen strength are analyzed by numerical simulation. The research results show that the 3D meso‐scale model of reinforced concrete considers the meso‐scale structure of reinforced concrete more realistically, and can better reflect the damage change process inside the material in the dynamic loading process. The weak interface effect caused by reinforcement can lead to the slight weakening of the dynamic strength of the material, but at the same time the weak interface effect of the reinforcement is also the main reason why the residual form of reinforced concrete remains well aligned with the shape of the reinforcement frame after the failure. [ABSTRACT FROM AUTHOR]

In this paper, the Noether theorems and their inverse theorems for generalized Chaplygin systems with two types of nonstandard Lagrangians, related to exponential and power-law Lagrangian, are explored and presented. The variational principles for the Chaplygin systems with nonstandard Lagrangian are derived, and the generalized Chaplygin equations for the corresponding systems are established, the Noether transformations are considered, from which the corresponding conserved quantities are deduced. And their inverse theorems for nonstandard generalized Chaplygin systems are given. Two examples show the validity of the results. [ABSTRACT FROM AUTHOR]

To improve the corrosion resistance of magnesium alloy as a medical implant, a Zr-containing micro-arc oxidation-polylactic acid (MAO-PLA) composite coating was successfully prepared. The microstructure, phase composition, and corrosion resistance of the coating were studied by scanning electron microscope, X-ray diffractometer, and electrochemical workstation. The results show that the micropores and cracks on the surface of MAO coating can be sealed by PLA, which makes the corrosion rate of the sealed sample minimum. And, in the process of immersion corrosion of simulated body fluid (SBF), calcium and phosphorus deposits are formed on the surface of the composite coating, and PLA coating plays a major role in protecting the substrate. The composite coating can be applied to degradable magnesium-based orthopedic implants. [ABSTRACT FROM AUTHOR]

In order to make titanium alloy implants have better corrosion resistance in the human body, selenium-containing coating was added to the surface of Ti6Al7Nb through micro-arc oxidation. The results indicate that the coating has a higher thickness and lower roughness after the addition of selenium element. XRD, SEM, and XPS analysis showed that selenium element was successfully added into the coating. Then the dynamic polarization curve and EIS indicate that the prepared samples have better corrosion resistance in SBF solution compared to the unadded samples, (icorr) and (Ecorr) are 2.695 × 10−8 A·cm−2 and 0.101 V, respectively. The addition of selenium helps to improve the biological corrosion resistance of the sample in body fluids. [ABSTRACT FROM AUTHOR]

To improve the corrosion resistance of 7075 aluminum alloy microarc oxidation (MAO) coating, graphene of 3 g/L was adsorbed and deposited in the coating. Then, the microarc oxidation–sol–gel (MAO-SG) composite coating was obtained by sealing the micropores of the coating with TiO2 sol–gel. Electrochemical tests of 7075 aluminum alloy matrix, undoped sample, doped graphene sample and sealed sample were carried out in 3.5wt.% NaCl solution. The results show that compared with the blank sample, the self-corrosion potential of the sealed sample is increased by 98.1%, and the self-corrosion current density is reduced by 4 orders of magnitude. After immersion corrosion for 720 h, the corrosion rate of MAO-SG composite coating is 3.4 × 10–5 mm/a, and its corrosion resistance is still better than that of single MAO coating. This is due to the strong conductivity of graphene and the blocking effect of TiO2 sol–gel. [ABSTRACT FROM AUTHOR]

Balancing the relationship between straw returning and fertilizer, especially nitrogen fertilizer application is vital for achieving the goal of reducing fertilization and improving soil fertility. To better understand their combined effects on crop yield and nitrogen utilization, a study was conducted to explore the effects of straw returning and nitrogen fertilizer application on crop yield and nitrogen utilization. In contrast to straw return, nitrogen fertilizer application had a more significant effect on the crop yield. Straw ploughing led to significantly higher crop yield under the nitrogen fertilizer application rates of 0, 90, 150 kg/ha compared to straw mulching (P < 0.05). No significant differences for > 150 kg/ha concerning their effects on crop yield were observed between straw ploughing and mulching. The optimal residual return amount was 9000 kg/ha and straw return was not decisive to crop yield under the same nitrogen fertilizer application rate. Straw ploughing better promoted nitrogen uptake, utilization, harvest and retention than straw mulching and no residue addition when combined with nitrogen fertilizer application. These findings demonstrate that straw ploughing and 150 kg/ha nitrogen fertilizer application rate is a better combination for implementing stable production and enhancing nitrogen utilization synchronously in the chernozem of Northeast China. [ABSTRACT FROM AUTHOR]

In order to mitigate the degradation of black soil organic matter, this paper designed a field microplot experiment with different proportional mixtures of corn straw and peat with an equal carbon amount. Treatments included (ⅰ) no organic materials applied (CK), (ⅱ) Application of peat (P), (ⅲ) Peat and corn straw are 2:1(2/3P), (ⅳ) Peat and corn straw are 1:2(1/3P) and (ⅴ) Application of corn straw (0P). The humus composition and humic acid (HA) structural characteristics of black soil were studied using elemental analysis, Fourier transform infrared (FTIR) spectroscopy, fluorescence spectrum and thermogravimetric analysis. The results demonstrated that water-soluble substances carbon (WSS-C) content increased with the increase of straw application amount, SOC, humification rate (PQ) and carbon content of other humus fractions increased with the increase of peat application amount. In addition, the higher peat applied, the stronger the aromatic nature of HA structure, the more stable and complex the structure of HA, the higher corn straw applied, the stronger the aliphatic nature of HA structure, and the simpler the structure of HA. With the consideration of the humus composition and HA structural characteristics of black soil, the appropriate ratio of the application of corn straw and peat deemed 2:1. [ABSTRACT FROM AUTHOR]

There is a large number of missions that have been or will be launched soon that utilize the electric propulsion (EP), which is considered a key technology for applications in present and future space missions. Accomplishing an accurate measure of the thrust is a key aspect of the laboratory verification of EP systems. In the case of ground conditions and direct measurements, it is complicated to verify the thrusters, especially for some high power (>5 kW) thrusters. For this reason, we have developed an indirect method for measuring thrust. We have carried out an experiment with a Hall effect thruster (operated in the 250 W power range) and compared results against direct thrust measurements. The difficulties in the indirect measurement are analyzed, which provides a basis for the development of indirect thrust measurement. [ABSTRACT FROM AUTHOR]

Bursaphelenchus xylophilus became one of the most damaging forest pests in recent years in Hunan province, and caused remarkable losses of pine tree. In order to explore the effect of fire disturbance on the prevention of Monochamus alternatus and B. xylophilus. forests dominated by Pinus massoniana were taken as the object of the study in Daolin town, Ningxiang city, Hunan province, China. Three kinds of forest were selected, such as healthy forest of Pinus massoniana (Control I), infected forest without prevention(II), and infected forest with prevention(III). Then, 6 plots were set in every object forest. Three were the control plot, and the other three were treated with prescribed burning. We continuously investigated the number of M. alternatus and B. xylophilus before and after low intensity prescribed burning. The results indicated that the quantity of female M. alternatus in the three kinds of fire disturbance plots were reduced by 88.24%, 75.00% and 94.74%, respectively, while the males were reduced by 77.78%, 81.82% and 88.89% before and after the fire. There were significant differences for the quantity of M. alternatus before and after the prescribed burning (P<0.05). The results showed that the prevention efficacy of II-2 was the best. Within 10 to 20 days after the fire, the quantity of B. xylophilus carried by M. alternatus changed significantly. The average quantity of B. xylophilus carried by female and male M. alternatus dropped from 1135 to 6 and from 397 to 35, respectively. It showed that prescribed burning could reduce the population density of M. alternatus and carrying quantity of B. xylophilus of each M. alternatus. So prescribed burning could control the spread of pine wilt disease and prevent its outbreak. Prescribed burning has an important theoretical and practical significance in pine wilt disease prevention. [ABSTRACT FROM AUTHOR]

In this study, with the meso-scale model reliably validated in our previous work (Construction and Building Materials, 2018), the waveform features of plain concrete under various loading conditions and especially with considering stress non-equilibrium are reliably reproduced and predicted. Associating with waveform features, the violation indicator of the specimen stress equilibrium in the split Hopkinson pressure bar test is identified for concrete-like damage softening materials. The concrete material behaviors for stress non-equilibrium are further analyzed, e.g. the dynamic increase factor (DIF) and damage development, etc. The conception of "damage failure volume" is introduced, and a new method of defining the development of concrete dynamic damage is given in the numerical study. What's more, the "compression wave" and "double peak" phenomena observed in the experiment are further interpreted based on the means of numerical simulation. Waveform features how to reflect the concrete material properties is also concluded. The results show that, the disappearance of the "double peak" phenomenon of reflection curve under high strain rate can be regarded as the indicator of the violation of stress equilibrium. After the violation of the stress equilibrium, the relevant DIFs of the concrete specimen will not change significantly. Especially, the concrete specimen will turn into structural response from material response. The conception of "damage failure volume" can well explain the generation of the "double peak" phenomenon of the reflection curve. The "compression wave" phenomenon of reflection curve under lower strain rates is derived from the unloading expansion recovery of the concrete specimen. Furthermore, under the same loading condition, the amplitude of the first peak of the reflection curve can be used as the evaluation standard of the bonding quality between mortar and aggregates. [ABSTRACT FROM AUTHOR]

The relationship between the average penetration velocity, U ¯ , and the initial impact velocity, V 0 , in long-rod penetration has been studied recently. Experimental and simulation results all show a linear relationship between U ¯ and V 0 over a wide range of V 0 for different combinations of rod and target materials. However, the physical essence has not been fully revealed. In this paper, the U ¯ - V 0 relationship is comprehensively analyzed using the hydrodynamic model and the Alekseevskii–Tate model. In particular, the explicit U ¯ - V 0 relationships are derived from approximate solutions of the Alekseevskii–Tate model. In addition, the deceleration in long-rod penetration is discussed. The deceleration degree is quantified by a deceleration index, α = 2 μ ¯ / (K Φ Jp) ≈ Y p ρ p - 1 / 2 ρ p - 1 / 2 + ρ t - 1 / 2 V 0 - 2 , which is mainly related to the impact velocity, rod strength, and rod/target densities. Thus, the state of the penetration process can be identified and designed in experiments. [ABSTRACT FROM AUTHOR]

The feature of reinforcing bars is introduced into dynamic cavity-expansion theory. Based on the elastic–plastic response penetration model of plain (i.e., unreinforced) concrete (Forrestal and Tzou, 1997), a dynamic spherical cavity-expansion penetration model for reinforced-concrete targets is developed with consideration of the circumferential restriction effect derived from reinforcing bars in the crushed region. The theoretical solution and simplified calculation formula for the cavity radial stress in incompressible and compressible reinforced concrete are obtained by introducing a reinforcement ratio as the volume fraction of rebars in the concrete target. A damping function is presented to describe the restriction effect of a single layer of reinforcing bars on the surrounding concrete, thus establishing a model to calculate the penetration resistance of multilayer reinforced-concrete targets. Compared with test data for the penetration depth, this model considering the circumferential restriction effect produces better results compared with the existing theory. [ABSTRACT FROM AUTHOR]

The effects of agricultural waste return on the emissions of greenhouse gases (CO2, N2O and CH4) from corn farmland in the black soil region of Northeast China and its potential to increase temperature were studied to provide a theoretical basis for formulating reduction measures of agricultural greenhouse gas emissions. This study was conducted at the Experimental Station of China Agricultural University in Quanyangou, Lishu County, Siping City, Jilin Province. Static greenhouse gas chromatography was used to monitor soil greenhouse gas fluxes under different fertilization measures, and the different fertilization treatments were analyzed for comprehensive differences in greenhouse effects among corn fields. The results showed that the average CO2 fluxes and total emissions in response to the straw return treatment were the highest, reaching 388.96 mg⋅m-2⋅h-1 and 14718.97 kg⋅hm-2, respectively, and nitrogen topdressing fertilizer significantly increased CO2 emissions. With respect to CH4 emissions, single fertilizer-treated plots had the highest average absorbed flux and total absorption--0.042 mg⋅m-2⋅h-1 and 1.36 kg⋅hm-2, respectively, and with respect to N2O fluxes, the highest flux and amount were 0.153 mg⋅m-2⋅h-1 and 5.75 kg⋅hm-2, respectively. The global warming potential of the straw in situ treatment was significantly higher than that of the other treatments, and the global warming potential of the cattle manure treatment was lower than that of the single chemical fertilizer treatment, but the differences were not significant. Moreover, straw mulch increased CO2 emissions from black soils, and dry soils were shown to be important sinks of atmospheric CH4. Combinations of organic and inorganic fertilizers and individual fertilizers can reduce N2O emissions from soils. Therefore, to achieve higher corn yields and to reduce greenhouse gas emission intensities simultaneously, applications of organic and inorganic fertilizers constitute an ideal soil fertility method in the black soil region of Northeast China. [ABSTRACT FROM AUTHOR]

Soil organic carbon decomposition is regulated by soil physical and chemical properties, such as soil nitrogen (N) and soil substrate quality. In this study, soil samples from both N fertilization and control plots were collected at two depths in a Larix gmelinii plantation to determine if N addition elicits consistent responses in microbial respiration in bulk and rhizosphere soil, and to determine the temporal and spatial dynamics of soil organic carbon decomposition. Soil bulk and rhizosphere microbial respiration were determined using the NaOH solution absorption method. Soil microbial biomass was determined by a modified CHCL3 fumigation-extraction method. The greatest soil bulk and rhizosphere microbial respiration occurred in July. Soil rhizosphere microbial respiration was higher than bulk respiration at 0-10 cm and 10- 20 cm. The biggest reductions in soil microbial respiration induced by fertilization were 15.0% (bulk) and 19.6% (rhizosphere) at 0-10 cm in July, and 6.4% (bulk) and 7.9% (rhizosphere) at 10-20 cm in September. Fertilization did not influence the rhizosphere priming effect except for at 10-20 cm in May. Structural equation modeling revealed that soil microbial biomass carbon (MBC) and nitrogen (MBN) contributed directly to soil microbial respiration. Moreover, soil total N and organic carbon content were associated with soil microbial respiration through MBC and MBN. These results suggest that N fertilization suppresses soil organic carbon decomposition by decreasing soil microbial biomass, while C input induced by root exudates determined the rhizosphere priming effect, not soil microbes in the rhizosphere. [ABSTRACT FROM AUTHOR]

The effect of different long-term (2001-2016) tillage practices on soil nitrogen forms in different soil layers were studied to provide a scientific basis for evaluating soil fertility and establishing rational fertilization measures. Soil contents of total nitrogen (TN), particulate organic nitrogen (PON), microbial biomass nitrogen (MBN), water soluble organic nitrogen (WSON), NO3-N content, NH4-N content ammonium nitrogen and organic acid nitrogen component contents were measured under notillage (NT) and mould plow (MP) treatments based on a long-term (16 year) conservation tillage experiment in Northeast China. The results showed that no-tillage increased soil total nitrogen, active nitrogen, inorganic nitrogen and organic nitrogen content, which varied with soil depth. Compared with MP, NT significantly (p < 0.05) increased total nitrogen and active nitrogen content in the surface soil (0- 30 cm); TN, PON, MBN and WSON increased significantly (p < 0.05) by 28.32%, 23.07%, 15.13% and 25.21% in 0-5 cm and by 10.17%, 19.4%, 15.97%, and 31.33% in 5-10 cm, respectively. For soil inorganic nitrogen, the content of ammonium nitrate at 0-5 cm and at 5-10 cm under NT was significantly (p < 0.05) higher than that of MP by 28.1% and 32.13%, respectively, and the content of ammonium nitrogen in soil at 0-5 cm was significantly (p < 0.05) higher, by 12.86%, than that of MP. No-tillage significantly increased the content of total hydrolysable nitrogen, hydrolysable ammonia nitrogen, hydrolysable amino acid nitrogen and hydrolysable unidentified nitrogen in the 0-10 cm soil layer, but no significant effect was found on the content of hydrolysable amino sugar nitrogen. Soil nitrogen content was closely related to tillage practices. These results suggest that no-tillage was beneficial in augmenting soil nitrogen supply capacity by increasing soil total nitrogen, active nitrogen, inorganic nitrogen and organic nitrogen content. [ABSTRACT FROM AUTHOR]

The Alekseevskii-Tate model is the most successful semi-hydrodynamic model applied to long-rod penetration into semi-infinite targets. However, due to the nonlinear nature of the equations, the rod (tail) velocity, penetration velocity, rod length, and penetration depth were obtained implicitly as a function of time and solved numerically. By employing a linear approximation to the logarithmic relative rod length, we obtain two sets of explicit approximate algebraic solutions based on the implicit theoretical solution deduced from primitive equations. It is very convenient in the theoretical prediction of the Alekseevskii-Tate model to apply these simple algebraic solutions. In particular, approximate solution 1 shows good agreement with the theoretical (exact) solution, and the first-order perturbation solution obtained by Walters et al. (Int. J. Impact Eng. 33:837-846, 2006) can be deemed as a special form of approximate solution 1 in high-speed penetration. Meanwhile, with constant tail velocity and penetration velocity, approximate solution 2 has very simple expressions, which is applicable for the qualitative analysis of long-rod penetration. Differences among these two approximate solutions and the theoretical (exact) solution and their respective scopes of application have been discussed, and the inferences with clear physical basis have been drawn. In addition, these two solutions and the first-order perturbation solution are applied to two cases with different initial impact velocity and different penetrator/target combinations to compare with the theoretical (exact) solution. Approximate solution 1 is much closer to the theoretical solution of the Alekseevskii-Tate model than the first-order perturbation solution in both cases, whilst approximate solution 2 brings us a more intuitive understanding of quasi-steady-state penetration. [ABSTRACT FROM AUTHOR]

We further consider the effect of rod strength by employing the compressible penetration model to study the effect of compressibility on hypervelocity penetration. Meanwhile, we define different instances of penetration efficiency in various modified models and compare these penetration efficiencies to identify the effects of different factors in the compressible model. To systematically discuss the effect of compressibility in different metallic rod-target combinations, we construct three cases, i.e., the penetrations by the more compressible rod into the less compressible target, rod into the analogously compressible target, and the less compressible rod into the more compressible target. The effects of volumetric strain, internal energy, and strength on the penetration efficiency are analyzed simultaneously. It indicates that the compressibility of the rod and target increases the pressure at the rod/target interface. The more compressible rod/target has larger volumetric strain and higher internal energy. Both the larger volumetric strain and higher strength enhance the penetration or anti-penetration ability. On the other hand, the higher internal energy weakens the penetration or anti-penetration ability. The two trends conflict, but the volumetric strain dominates in the variation of the penetration efficiency, which would not approach the hydrodynamic limit if the rod and target are not analogously compressible. However, if the compressibility of the rod and target is analogous, it has little effect on the penetration efficiency. [ABSTRACT FROM AUTHOR]

It is often claimed that earthworms exert a huge influence on soil macroporosity. Nevertheless, gaps still exist in our knowledge of rangeability in soil macroporosity caused by earthworm activity. Earthworms are generally recognized as ecosystem engineers vital for soil ecosystem function and services, but the potential mechanism of earthworm response to the combination of extreme drought and conservation tillage has not yet been identified. To improve understanding of the effect of the earthworm on soil macroporosity and how earthworms, through soil macroporosity, respond to extreme drought and conservation tillage, a study was conducted to compare soil macroporosity under different tillage treatments with the same number of earthworms in incubation conditions and soil structural properties (soil penetration resistance, infiltration rate, saturated hydraulic conductivity) associated with macroporosity, together with crop yields under different tillage systems and drought stress in field conditions. The results show that earthworms only increase the volume of large macropores (>100 μm) rather than small macropores (30-100 μm) under different tillage systems. Earthworms played a positive role in the development of large macropores, as evidenced by the formation of paths of least resistance under high penetration resistance, higher infiltration rate and saturated hydraulic conductivity and no obvious yield loss under extreme drought and conservation tillage in a Chinese Mollisol. [ABSTRACT FROM AUTHOR]

Here the transcriptome and differential gene expression in the adult brain and gonads of the Chinese sea perch Lateolabrax maculatus were reported. A total of 78 256 909 clean reads were generated from the adult brain, ovary and testis by using the Illumina HiSeq2000 platform and assembled into 274 909 contigs. A total of 31 683 unigenes were annotated based on sequence similarity and 20 702 unigenes were found to exhibit 8237 gene ontology terms and 3888 signal pathways. Transcripts of 26 623 unigenes were present in all of the tissues, whereas pairwise comparisons revealed that 671/367, 496/315 and 1668/580 unigenes were up-down regulated by at least two-fold between the brain and ovary, ovary and testis and brain and testis, respectively. Homology search led to the identification of reproduction-associated genes of the brain-gonad axis, including those involved in sex differentiation and maintenance. The data provided an integrated and comprehensive transcriptome resource for L. maculatus, which could be used for further research on hypothalamus-pituitary-gonad axis gene function, reproduction regulation and sex-biased gene expression. [ABSTRACT FROM AUTHOR]

An SRTM DEM-aided DEM extraction method for island and reef is proposed to solve the problem of island and reef DEM extraction based on satellite imagery. The SRTM DEM is fully integrated into this method, namely, it is used to provide initial elevation for DEM and also to mark the sea area points in order to avoid the adverse effect of sea area image on DEM extraction. When determining elevations of grid points, only the valid land area points (VLPs) are taken into account. On the basis of initial elevation, the image coordinates of VLPs in multi-view images are determined and precise coordinates of conjugate points are obtained based on least square matching, then ground coordinates of VLPs are acquired by forward intersection. Finally, the elevations of VLPs are determined based on these object space points through data interpolation, and the sea area points are set as a uniform value. Experimental results show that the method can effectively solve the problem of island and reef DEM extraction. It can effectively extract DEM from island and reef satellite images regardless of the land area proportion, and island and reef can be completely extracted. Accuracy of the extracted DEM would improve with the increase of DEM resolution; when the resolution is relative high, the accuracy is consistent with SRTM DEM. The computational efficiency depends on the land area proportion and DEM resolution. [ABSTRACT FROM AUTHOR]

Biased assessment of tillage impacts on soil organic carbon (SOC) sequestration are often associated with a lack of information on the initial level of SOC stocks. The present study reported the changes in SOC concentrations and stocks following 10-year different tillage practices relative to the initial SOC levels. The tillage trial included no tillage (NT), ridge tillage (RT) and mouldboard plough (MP) on a Black soil (Hapludolls) in Northeast China. Results showed that tillage, soil depth and time significantly affected SOC concentration and SOC stock. Tillage and crop residue retention had great impacts on the SOC concentrations in the top 0·1 m layer. Compared with MP and NT, RT resulted in higher SOC concentration and SOC stock in the plough layer (0–0·2 m), which became more obvious with time. The soil under NT and RT had higher stratification ratios (SR) of SOC (SR, the ratio of SOC concentration in 0–0·05 m to that in 0·1–0·2 m) than under MP. Significant positive and nearly identical linear relationships between the SR of SOC and the duration of tillage practices occurred for both NT and RT soils; the increased SR in NT resulted from both SOC increase in surface and SOC decrease in subsurface soils, but in RT, the increased SR was only from a substantial SOC increase in surface soil. Accordingly, the present study highlights that RT was more helpful than NT in carbon sequestration for the studied Black soil in Northeast China. [ABSTRACT FROM PUBLISHER]

Cattle are intermediate hosts for 2 zoonotic species of Sarcocystis, Sarcocystis hominis and Sarcocystis heydorni. Here we report S. heydorni from cattle for the first time in China. Sarcocysts of S. heydorni were found in muscle from 173 of 1,630 (10.6%) cattle in abattoirs (9.7% in skeletal muscles, 3.4% esophagus, 2.5% diaphragm, and 0.1% tongue; heart muscle was negative). By means of light microscopy, S. heydorni sarcocysts were thin-walled (<1 μm). Using transmission electron microscopy, the sarcocyst wall had short (0.3-0.5 × 0.5-0.9 μm) stubby protrusions, the tips of which contained electron-dense, disk-shaped plaques, similar to the sarcocyst wall type 29b. In preliminary transmission attempts, a human volunteer did not excrete sporocysts in feces after ingesting 579 sarcocysts S. heydorni isolated from cattle. Phylogenetic analysis using the 2 molecular markers (18S rRNA gene and mitochondrial cox1 gene) indicated S. heydorni shared the closest affinity with species of Sarcocystis, which employ ruminants as intermediate hosts and canids as definitive hosts. [ABSTRACT FROM AUTHOR]

Summary: This study determined the length–weight relationships (LWRs) and length–length relationships (LLRs) of seven freshwater fish from the Daning River, a tributary of the Yangtze River, southwest China. Specimens were collected between July 2016 and July 2017 using drift gill nets (mesh size 1, 2 and 3 cm), cage net (0.5 cm mesh size) and electroshock fishing techniques quaterly. Parameter b values of LWRs ranged from 2.647 to 3.276 (r2 > .963) and b values of LLRs ranged from 1.091 to 1.213(r2 > .985). Six new LLRs and seven new maximum length data are presented. The biometric data and their relationships are relevant to Fishers science to supplement other data sets needed for fisheries management. [ABSTRACT FROM AUTHOR]

Fe-Ni-W amorphous alloy platings were electrodeposited on the surface of S135 steel, and heat treatments at 125, 165, 205, 255, 305, 355 and 405°C were carried out on them. Corrosion resistance, hardness, structure and morphology of Fe-Ni-W amorphous alloys have been tested and analysed by means of polarisation curve, hardness test, X-ray diffraction and scanning electron microscopy, respectively. The results show that the as-plated Fe-Ni-W alloys are amorphous under this experimental condition. Autoclave corrosion test, together with polarisation curve results and general corrosion experiment, indicates that the best heat treatment temperature of Fe-Ni-W alloy electrodeposited on S135 steel is 165°C in this paper. [ABSTRACT FROM AUTHOR]

The present work built on a previous study of tillage trials, which found the effectiveness of least limiting water range (LLWR) as an indicator of soil organic carbon (SOC) mineralization under different tillage practices in a black soil of Northeast China in 2009. To improve the understanding of soil structure controls over SOC dynamics, a study was conducted to explore the relationship between LLWR, which was calculated based on soil bulk density and soil pore-size distribution, and the effects of LLWR, which was calculated based on soil bulk density and soil pore-size distribution on SOC mineralization following no tillage (NT) and mouldboard ploughing (MP). In contrast to MP, NT had a significantly greater volume of large macropores (>100 μm) at depths of 0–0·05 and 0·2–0·3 m, but a significantly lower volume of small macropores (30–100 μm) at depths of 0–0·05, 0·05–0·1, 0·1–0·2 and 0·2–0·3 m. The volume of meso- (0·2–30 μm) and micro-pores (<0·2 μm) at different depths under the two tillage practices were similar. Tillage-induced changes in soil bulk density and pore-size volumes affected the ability of soil to fulfil essential soil functions in relation to organic matter turnover. Soil pore-size distribution, especially small macropores greatly affected LLWR and there was a significant correlation between LLWR, which was calculated based on soil bulk density, and the proportion of small macropores. The proportion of small macropores were used to calculate LLWR instead of soil bulk density and the values for NT and MP soils ranged from 0·073 to 0·148 m3 water/m3 soil. Using the proportion of small macropores rather than bulk density in the calculation of LLWR resulted in more sensitive indications of SOC mineralization. Variation in the proportion of small macropores can help characterize the impacts of tillage practices on dynamics of LLWR and SOC sequestration. [ABSTRACT FROM PUBLISHER]

A cyp19a gene that contains nine exons and eight introns was identified from Carassius auratus and was mainly expressed in the ovary. The cyp19a mRNA level after hatching was initially low, but began to increase from 25 days after hatching. A number of cis‐acting elements, such as the oestrogen receptor, steroidogenic factor 1 and SOX‐5 recognition sites, were found in the promoter of the cyp19 gene, which possesses a promoter function confirmed by a recombination green fluorescent protein checking system in vitro. [ABSTRACT FROM AUTHOR]

Study design:We introduced a lentiviral vector containing the neuroglobin (Ngb) gene into the injured spinal cords to evaluate the therapeutic potential of Ngb in a rabbit model of spinal cord injury (SCI).Objectives:It is not clear whether Ngb has the neuroprotective role to SCI. The purpose of this study was to investigate the possible protective effects of the Ngb overexpression on traumatic SCI in rabbits.Setting:Department of Orthopedic Surgery, The First Affiliated Hospital, Fujian Medical University, Fuzhou, People's Republic of China.Methods:A lentiviral vector containing Ngb gene was constructed and injected at the SCI sites 24 h after SCI. The rabbits' motor functions were evaluated by the Basso-Beattie-Bresnahan rating scale. Quantitative real-time PCRs, western blots, malondialdehyde (MDA) tests and terminal deoxynucleotidyl transferase-mediated UTP end labeling assays were also performed.Results:The Ngb expression in the LV-Ngb group increased significantly at days 7, 14 and 21. A more significant functional improvement was observed in the LV-Ngb group compared with the improvements in all other groups at days 14 and 21. The traumatic SCI seemed to lead to an increase in the levels of MDA and in the number of the apoptotic cells, which could be prevented by the LV-Ngb treatment.Conclusion:This study demonstrated that the Ngb overexpression may have potential therapeutic benefits for both reducing secondary damages and improving the outcomes after traumatic SCI. [ABSTRACT FROM AUTHOR]

Two complementary (c)DNA fragments, including the complete open reading frame of fabp2 from the common carp Cyprinus carpio, were cloned by reverse-transcription polymerase chain reaction (RT-PCR). Both were putative intestinal-type fabp genes, named fabp2a and fabp2b. fabp2b was mainly expressed in the intestine and the brain. This gene, however, was nearly not expressed in the liver, heart, pancreas and muscle. fabp2a was only expressed at a very low level in the intestine. Western blot also showed that Fabp2 is relatively highly expressed in the intestine and the brain. Immunohistochemical analysis revealed that Fabp2 is widely distributed in the mucosa of the intestine. These findings provide novel insights into the fabp2 gene molecular evolution, as well as its potential features in the intestine and the brain. [ABSTRACT FROM AUTHOR]

Single emitters have been considered as sources of single photons in various contexts, including cryptography, quantum computation, spectroscopy and metrology. The success of these applications will crucially rely on the efficient directional emission of photons into well-defined modes. To accomplish high efficiency, researchers have investigated microcavities at cryogenic temperatures, photonic nanowires and near-field coupling to metallic nano-antennas. However, despite impressive progress, the existing realizations substantially fall short of unity collection efficiency. Here, we report on a theoretical and experimental study of a dielectric planar antenna, which uses a layered structure to tailor the angular emission of a single oriented molecule. We demonstrate a collection efficiency of 96% using a microscope objective at room temperature and obtain record detection rates of ∼50 MHz. Our scheme is wavelength-insensitive and can be readily extended to other solid-state emitters such as colour centres and semiconductor quantum dots. [ABSTRACT FROM AUTHOR]

Glomerular microthrombosis (GMT) is a common vascular change in patients with lupus nephritis (LN). The mechanism underlying GMT is still unknown. In our previous study, we found that the level of IgG anti-β2 glycoprotein I (β2GPI) antibodies was higher in the LN-GMT group than in the LN-non-GMT group, which indicated that anti-β2GPI antibodies may play a role in GMT formation. Many studies have demonstrated that the activation of the classical complement pathway may play a critical role in fetal loss and aPL-induced thrombosis formation. To investigate whether complement activation plays a role in GMT formation and to evaluate its relationship with aPL, we prospectively investigated deposition of C4d in 155 renal biopsy specimens of LN patients. The results revealed a strong relationship between the intensity of glomerular C4d staining and the presence of microthrombi (p<0.001). The detection rate of IgG anti-b2GPI antibodies was higher in the LN-GMT group than in the LN-non-GMT group (p<0.05). Further, the intensity of glomerular C4d staining was significantly related with IgG anti-β2GPI antibodies (p<0.05). The results of our study suggest that anti-β2GPI antibodies may play a role in GMT formation, and this process might involve complement activation. [ABSTRACT FROM AUTHOR]

In cereals, albinism is a major obstacle to produce doubled haploids (DH) for breeding programs. In order to identify QTLs for green plant percentage in barley anther culture, a specific population was developed. This population, consisting of 100 DH lines, was generated by crossing the model cultivar for anther culture “Igri” with an albino-producing DH line (DH46) selected from Igri × Dobla, in search of a maximum segregation for the trait and minimum for the other anther culture variables. A combination of bulked segregant analysis and AFLP methodology was used to identify markers linked to the trait. A linkage map was constructed using these AFLPs, together with RAPD, STS and SSR markers. This study identified a new QTL for green plant percentage on chromosome 3H and confirmed the previously reported one on chromosome 5H. Up to 65.2% of the phenotypic variance for this trait was explained by the additive effects of these two QTLs. Thirty elite cultivars of barley from different origin, row type, growth habit and end use, were selected to validate these QTLs. Since two of the markers linked to the QTLs were AFLPs, we successfully converted them into simple PCR-based SCAR markers. Only the SSR HVM60, on chromosome 3H, was significantly associated with the trait, explaining near 20% of the phenotypic variance. Among the allelic variants identified for this marker, HVM60-120bp was associated with the highest values of green plant percentage. [ABSTRACT FROM AUTHOR]

This article discusses the development and testing of continuous-flow microextraction techniques coupled with high performance liquid chromatography for the determination of aromatic amines. According to the authors, continuous-flow microextraction is very effective in the detection of 4-chloroaniline in the algae Chlamydomonas reinhardtii in contaminated waters. They argue that the pre-treatment procedure is relatively simple, low cost, and friendly to the environment so it has tremendous potential in trace analysis in polluted waters.

The locus coeruleus (LC) harbors a compact group of noradrenergic cell bodies projecting to virtually all parts of the central nervous system. By using combined measurements of amperometry and patch-clamp, quantal vesicle release of noradrenaline (NA) was detected as amperometric spikes, after depolarization of the LC neurons. After a pulse depolarization, the average latency of amperometric spikes was 1,870 ms. whereas the latency of glutamate-mediated excitatory postsynaptic currents was 1.6 ms. A substantial fraction of the depolarization-induced amperometric spikes originated from the somata. In contrast to glutamate-mediated excitatory postsynaptic currents, NA secretion was strongly modulated by the action potential frequency (0.5-50 Hz). Somatodendritic NA release from LC upon enhanced cell activity produced autoinhibition of firing and of NA release. We conclude that, in contrast to classic synaptic transmission, quantal NA release from LC somata is characterized by a number of distinct properties, including long latency and high sensitivity to action potential frequency. [ABSTRACT FROM AUTHOR]

Erianthus arundinaceus has a number of important agronomic traits including good ratooning ability, tolerance to both drought and water logging, disease resistance and vigour and is of interest as a potential source of parental germplasm to sugarcane breeders. However, to date, attempts to produce fertile hybrids between sugarcane ( Saccharum spp.) and E. arundinaceus have been unsuccessful. Microsatellite markers that generated genus-specific markers and were highly polymorphic within sugarcane were identified. The microsatellite markers and 5S rDNA PCR were used to screen intergeneric (F1) clones from Saccharum officinarum × E. arundinaceus crosses, and two Saccharum backcross progeny (BC1) populations derived from crosses between selected F1 clones and sugarcane ( Saccharum spp.), to identify genuine Saccharum spp. BC1 progeny. The 5S rDNA PCR marker and highly polymorphic microsatellites with Erianthus-specific bands confirmed the F1 parent of the two putative BC1 populations was a S. officinarum × E. arundinaceus hybrid and allowed the identification of the genuine BC1 progeny from selfs of the F1 parent. This is the first verification of BC1 progeny from an F1 intergeneric hybrid × sugarcane ( Saccharum spp.) clone with molecular markers and confirms the introgression of E. arundinaceus germplasm into sugarcane. It should now be possible to exploit genes of value from E. arundinaceus in sugarcane breeding programmes. [ABSTRACT FROM AUTHOR]

This article focuses on the influence of iron ion irradiation on the aqueous corrosion resistance of zircaloy-4. Materials irradiated with energetic particles respond by undergoing changes in the internal microstructures, phase distributions, dimensions, mechanical and corrosion properties. Heavy ions in the MeV energy range impart energy to the atoms of the target materials and produce a displacement cascade consisting of highly localized interstitials and vacancies. There is a growing interest in the effect of irradiation on the structure and the corrosion property of zirconium alloys in recent years.