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The microstructural evolution of DD9 single crystal superalloy turbine blade was studied after heat treatment. In comparison to the as-cast microstructures where the sizes of the γ′ precipitates have an obvious difference between the dendritic core and interdendritic regions, the γ′ sizes of the heat-treated microstructures tend to be uniform and more cubic. And in the heat-treated microstructures, the γ′ sizes and the related size dispersion degrees of the dendritic cores are slightly increased, while those of the interdendritic regions are obviously decreased. After all, all the γ′ sizes follow the normal distribution law. With the raise of section thickness, the γ′ sizes tend to increase and the related size dispersion degrees are enhanced during the cooling process after heat treatment, and the γ-γ′ eutectics are dissolved, left little residual eutectics and pores.

Effects of low angle boundaries (LABs) on the stress rupture properties of bicrystals of a nickel-based third generation single crystal superalloy at 1093 °C/158 MPa were investigated. The results show that the effect of LABs on the stress rupture elongation of the alloy is higher than that of the stress rupture life at 1093 °C/158 MPa. As the misorientation angle of the LABs reaches 9.0°, the stress rupture life of the alloy with LABs can still retain nearly 50% of that with LABs of 0° at 1093 °C/158 MPa; while the stress rupture elongation of the alloy with LABs drops obviously when the misorientation angle of the LABs is larger than 6.5°. The fracture surfaces of stress ruptured alloy with LABs of 0°~2.9° are characterized by dimple features, while those with LABs of 6.5°~12.3° all exhibit intergranular fracture features. Apparent dimple features can be observed at the intergranular fracture surface of the alloy with LABs of 6.5° and the elongation of it is high. However, obvious dendrite features can be observed at the intergranular fracture surfaces of the alloy with LABs of 7.6°~12.3° and the elongations of them are relatively low.

Simulating the stochastic traffic load has been an important issue for bridge condition evaluation. This paper proposes an improved cellular automaton for stochastic traffic load simulation with consideration of axle load and microscopic interaction. The cells, neighbors, transition rules and boundary conditions in the improved model are all redefined. The cell length can be manually defined with any value. The vehicle load can be precisely simulated using axle load if the cell length is set small or using concentrated load when a large cell length is defined. Acceleration based transition rules are proposed, and different acceleration for each vehicle can be computed to more reasonably simulate the microscopic behavior. The feasibility of the proposed model is validated through comparisons on traffic flow simulation and load effect quantification with in-field weigh in motion data and other models. The results indicate that the proposed model improves the existing models both in vehicle load simulation and traffic flow simulation and can be used for stochastic traffic load simulation for bridges with any length.

In this study, the variational method concerning displacement components is applied to solve the large deformation problem of a thin cylindrical shell with its four sides fully fixed and under uniformly distributed loads, in which the material that constitutes the shell has a bimodular effect, in comparison to traditional materials, that is, the material will present different moduli of elasticity when it is in tension and compression. For the purpose of the use of the displacement variational method, the physical equations on the bimodular material model and the geometrical equation under large deformation are derived first. Thereafter, the total strain potential energy is expressed in terms of the displacement component, thus bringing the possibilities for the classical Ritz method. Finally, the relationship between load and central deflection is obtained, which is validated with the numerical simulation, and the jumping phenomenon of thin cylindrical shell with a bimodular effect is analyzed. The results indicate that the bimodular effect will change the stiffness of the shell, thus resulting in the corresponding change in the deformation magnitude. When the shell is relatively thin, the bimodular effect will influence the occurrence of the jumping phenomenon of the cylindrical shell.

Aims Understanding the patterns and drivers of carbon isotope discrimination (13Δ) in C3 and C4 functional groups is critical for predicting C3/C4 vegetation ratio from the isotopic composition of soil organic matter. In this study, we aimed to evaluate how intraspecific variation will modify functional group-level 13Δ values and the associated prediction of C3/C4 vegetation ratio. Methods We investigated 13Δ of 726 individual plants (96 species; C3 and C4 functional groups) and topsoil organic matter in 26 grassland communities along an aridity gradient in northern China. The fraction of C4 contribution was calculated with mixing models that considered: (i) both intra- and interspecific effects on the 13Δ values of C3 and C4 functional groups; (ii) only interspecific effects; or (iii) none of these effects. Important Findings We found divergent responses of plant 13Δ at the intraspecific level to the changes of aridity across the gradient. The 13Δ of both C3 and C4 functional groups was negatively correlated with an aridity index, with higher sensitivity for C3 than for C4 functional groups. Intraspecific 13Δ variation played a key role in driving the total 13Δ variations of C3 plants. Overlooking such intraspecific effect in mixing models led to a greatly increased fraction of C4 contribution to soil organic carbon. A correction for the effects of intraspecific variation is therefore essential for correctly inferring C3/C4 vegetation ratio in the past. Our findings provide basic information for the reconstruction of past vegetation change from bulk materials in arid and semiarid biomes.

Post-traumatic stress disorder (PTSD) is a devastating mental illness with high morbidity and major social and economic burden. Currently, there is no promising therapy available for the treatment of PTSD. Some clinical studies showed that ketamine could effectively alleviate PTSD symptoms. However, it is still unclear which brain region ketamine targets and how it attenuates the PTSD-like effects. In this study, we examined the effect of ketamine on fear generalization (a core symptom of PTSD) by using a mice model of fear generalization induced by fear conditioning procedure. Before retrieval, ketamine was locally infused into the nucleus accumbens (a brain region closely associated with PTSD). Fear generalization mice were subjected to behavioral testing and biochemical assessments, following ketamine infusion. The results showed that the foot shock strength-dependently induced fear generalization in mice with increased c-fos activity, and a lower level of GluR1(S845), GluR1(S831) protein, and a higher level of P-GluN2B protein in the nucleus accumbens (NAc). Local infusion of ketamine into NAc decreased the fear generalization together with an increased level of GluR1(S845), GluR1(S831) protein, and decreased level of P-GluN2B protein. Altogether, these results conclude that ketamine might affect the glutamatergic signaling in the NAc to attenuate the fear generalization in mice.

We investigate the rotating wave approximation applied in the high-spin quantum system driven by a linearly polarized alternating magnetic field in the presence of quadrupole interactions. The conventional way to apply the rotating wave approximation in a driven high-spin system is to assume the dynamics being restricted in the reduced Hilbert space. However, when the driving strength is relatively strong or the driving is off resonant, the leakage from the target resonance subspace cannot be neglected for a multi-level quantum system. We propose the correct formalism to apply the rotating wave approximation in the full Hilbert space by taking this leakage into account. By estimating the operator fidelity of the time propagator, our formalism applied in the full Hilbert space unambiguously manifests great advantages over the conventional method applied in the reduced Hilbert space.

Fear memory is critical for individual survival. However, the maladaptive fear response is one of the hallmarks of fear-related disorders, which is characterized by the failure to discriminate threatening signals from neutral or safe cues. The biological mechanisms of fear discrimination remain to be clarified. In this study, we found that the nucleus accumbens (NAc) was indispensable for the formation of cued fear memory in mice, during which the expression of DNA methyltransferase 3a gene (DNMT3a) increased. Injection of Zebularine, a nonspecific DNMT inhibitor, into NAc immediately after conditioning induced a maladaptive fear response to neutral cue (CS

Stress-induced neuroepigenetic programming gains growing more and more interest in the studies of the etiology of posttraumatic stress disorder (PTSD). However, seldom attention is focused on DNA demethylation in fear memory generalization, which is the core characteristic of PTSD. Here, we show that ten-eleven translocation protein 3 (TET3), the most abundant DNA demethylation enzyme of the TET family in neurons, senses environmental stress and bridges neuroplasticity with behavioral adaptation during fear generalization. Foot shock strength dependently induces fear generalization and TET3 expression in nucleus accumbens (NAc) in mice. Inhibition of DNA demethylation by infusing demethyltransferase inhibitors or AAV-Tet3-shRNA virus in NAc enhances the fear generalization and anxiety-like behavior. Furthermore, TET3 knockdown impairs the dendritic spine density, PSD length, and thickness of neurons, decreases DNA hydroxymethylation (5hmC), reduces the expression of synaptic plasticity-related genes including Homer1, Cdkn1a, Cdh8, Vamp8, Reln, Bdnf, while surprisingly increases immune-related genes Stat1, B2m, H2-Q7, H2-M2, C3, Cd68 shown by RNA-seq. Notably, knockdown of TET3 in NAc activates microglia and CD39-P2Y12R signaling pathway, and inhibition of CD39 reverses the effects of TET3 knockdown on the fear memory generalization and anxiety. Overexpression of TET3 by Crispr-dSaCas9 virus delivery to activate endogenous Tet3 in NAc increases dendritic spine density of neurons in NAc and reverses fear memory generalization and anxiety-like behavior in mice. These results suggest that TET3 modulates fear generalization and anxiety via regulating synaptic plasticity and CD39 signaling pathway.

The adsorption and wetting on quartz surfaces by aqueous solutions of xylyl-substituted biquaternary ammonium salt gemini surfactants with different spacer groups (C3 and C6), have been investigated. The interfacial properties of surfactant solutions such as contact angle, adhesional tension (γLV cos θ), quartz–water interfacial tension (γSL) as well as adhesion work (WA) have been estimated. The obtained results show that C3 and C6 have similar adsorption behavior on quartz surfaces. Before critical micelle concentration (cmc) is reached, the contact angles of gemini surfactants slowly increase with the increasing concentration, and the adsorption amount at the water–air interface is almost the same as those at a quartz–water interface. After reaching cmc, the gemini surfactant Cn molecules form a more compact adsorption film through bending the flexible spacer chain, instead of forming a bi-layer. As a result, a further increase in quartz–liquid interfacial tension (γSL) and a consequent increase in contact angle have been observed after cmc. Gemini C6 shows a stronger ability towards hydrophobic modification at a quartz surface than C3, demonstrating the contribution of the longer methylene spacer to the hydrophobic modification of the quartz surface.

Fear memories are critical for survival. Nevertheless, over-generalization of these memories, depicted by a failure to distinguish threats from safe stimuli, is typical in stress-related disorders. Previous studies have supported a protective role of ketamine against stress-induced depressive behavior. However, the effect of ketamine on fear generalization remains unclear. In this study, we investigated the effects of ketamine on fear generalization in a fear-generalized mouse model. The mice were given a single sub-anesthetic dose of ketamine (30 mg/kg, i.p.) 1 h before, 1 week before, immediately after, or 22 h after fear conditioning. The behavioral measure of fear (indicated by freezing level) and synaptic protein expression in the basolateral amygdala (BLA) and inferior-limbic pre-frontal cortex (IL-PFC) of mice were examined. We found that only ketamine administered 22 h after fear conditioning significantly decreased the fear generalization, and the effect was dose-dependent and lasted for at least 2 weeks. The fear-generalized mice showed a lower level of brain-derived neurotrophic factor (BDNF) and a higher level of GluN2B protein in the BLA and IL-PFC, and this was reversed by a single administration of ketamine. Moreover, the GluN2B antagonist ifenprodil decreased the fear generalization when infused into the IL-PFC, but had no effect when infused into the BLA. Infusion of ANA-12 (an antagonist of the BDNF receptor TrkB) into the BLA or IL-PFC blocked the effect of ketamine on fear generalization. These findings support the conclusion that a single dose of ketamine administered 22 h after fear conditioning alleviates the fear memory generalization in mice and the GluN2B-related BDNF signaling pathway plays an important role in the alleviation of fear generalization. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s12264-019-00422-4) contains supplementary material, which is available to authorized users.

Variations in plant nitrogen (N) and phosphorus (P) concentrations and ratios have great implications for primary productivity and nutrient cycling. Here, we reported their changes at functional group and community levels along an aridity gradient. We carried out a field investigation and set up 26 sampling sites along a transect in the drylands of northern China to examine the responses of plant nutrient status to increasing aridity and the relationships between plant and soil nutrients. The responses of N and P concentrations to increasing aridity differed between woody (sub-) shrubs and herbaceous species (including annual/biennial forbs and grasses, perennial forbs and perennial grasses). Nitrogen and P concentrations of shrubs decreased while those of herbs generally increased with increasing aridity. Plant N:P ratios increased significantly with increasing aridity for the plant functional groups and at the community level. At both organizational levels, nutrient concentrations in plants were negatively related to those in soils. Our results indicated that the responses of plant nutrition to aridity were dependent on plant functional group. Plant growth appeared increasingly limited by P, and plant and soil nutrients become increasingly decoupled at large spatial scale with increasing aridity.

Aim To identify mutations with whole exome sequencing (WES) in a Chinese X-linked retinitis pigmentosa (XLRP) family. Methods Patients received the comprehensive ophthalmic evaluation. Genomic DNA was extracted from peripheral blood and subjected to SureSelect Human All Exon 6+ UTR exon capture kit. The exons were sequenced as 100 base paired reads on Illumina HiSeq2500 system. Only mutations that resulted in a change in amino acid sequence were selected. A pattern of inheritance of the RP family was aligned to identified causal mutation. Results We analysed the data of WES information from XLRP family. The analysis revealed a hemizygous large genomic deletion of RPGR c.29_113del was responsible for this XLRP. The gross deletion lead to a frame-shift mutation and generate stop codon at 7 animo acid behind Asp (D10Afs*7), which would serious truncate RPGR protein. The novel frame-shift mutation was found to segregate with retinitis pigmentosa (RP) phenotype in this family. Bilateral myopia was present on the male patients, but carrier female showed unilateral myopia without RP. Conclusion Our study identifies a novel frame-shift mutation of RPGR in a Chinese family, which would expand the spectrum of RPGR mutations. The geno-phenotypic analysis reveals a correlation between RP and myopia. Although exact mechanism of RP related myopia is still unknown, but the novel frame-shift mutation will give our hit on studying the molecular pathogenesis of RP and myopia.

Previous studies support a critical role of hippocampus in contextual fear memory. Structural and functional alterations of hippocampus occur frequently in posttraumatic stress disorders (PTSD). Recent reports reveal that knockout of CLC-3, a member of the CLC family of anion channels and transporters, leads to neuronal degeneration and loss of hippocampus. However, the role of CLC-3 in contextual fear memory remains unknown. Using adenovirus and adeno-associated virus gene transfer to knockdown CLC-3 in hippocampal CA1, we investigate the role of CLC-3 in contextual fear memory. CLC-3 expression is increased in hippocampal CA1 after formation of long-term contextual fear memory. Knockdown of CLC-3 by adenovirus infusion in hippocampal CA1 significantly attenuates the contextual fear memory, reduces spine density, induces defects of excitatory synaptic ultrastructure showed by the decreased PSD length, PSD thickness and active zone length, and impairs L-LTP induction and maintenance. Knockdown of CLC-3 also induces the synaptic NMDAR subunit composition to an increased GluN2A/GluN2B ratio pattern and reduces the activity of CaMKII-α. Furthermore, selectively knockdown of CLC-3 in excitatory neurons by adeno-associated virus driven from CaMKII-α promoter is sufficient to impair long-term contextual fear memory. These findings highlight that CLC-3 in hippocampal CA1 is necessary for contextual fear memory.

At temperatures ranging from 760 to 1100 °C, the tensile properties of a nickel-based third generation single crystal superalloy DD9 with [100], [120] and [110] orientations were studied. The microstructures and fracture surfaces were observed by OM, SEM and TEM. Results show that the tensile strength of [100] specimen is higher than that of [120] and [110] specimens at 760 and 850 °C; while at the temperatures higher than 980 °C, the tensile strength of all specimens has little difference. The fracture mechanisms of [100], [120] and [110] specimens are the same at 760 and 980 °C. At 1100 °C, the fracture surfaces of [100] and [120] specimens are characterized by dimple features; while [110] specimen shows mixed quasi-cleavage and dimple featured fracture surfaces. At 760 °C, obvious superlattice stacking faults (SSFs) are observed only in [100] specimen; while at 1100 °C, the dislocation configurations of all specimens are similar. The difference in the number of potential active slip systems in [100], [120] and [110] specimens during the tensile deformation process is the main reason for the transverse tensile anisotropy.

Hepatic injury is one of the most challenging diseases in clinical medicine. Hepatic injury is accompanied by hepatocyte apoptosis and leads to hepatic fibrosis and cirrhosis, which may cause liver cancer and increased mortality. Therefore, it is essential to investigate the regulation mechanism and therapeutic strategies for hepatic injury. In the study, the effects of Thymosin β4 (Tβ4) on Long intergenic noncoding RNA-p21 (lincRNA-p21)-mediated liver injury were investigated. Results showed that lincRNA-p21 overexpression promoted hepatocytes apoptosis, which was blocked by Tβ4. Besides, Tβ4 reversed the levels of cleaved caspase-3 and caspase-9 induced by lincRNA-p21. LincRNA-p21 overexpression also caused the pathological injury and fibrosis in hepatic tissues and increased the levels of fibrosis-related proteins (Collagen I, α-SMA and TIMP-1), and induced hydroxyproline and ALT production. However, Tβ4 reversed the effects of overexpression of lincRNA-p21 on hepatic injury and fibrosis. In vitro experiments, after lincRNA-p21 was overexpressed in hepatic stellate cells (HSCs), the proliferation ability and the levels of HSCs markers α-SMA and Desmin were increased. However, Tβ4 reversed the effects of lincRNA-p21 on HSCs. Furthermore, the PI3K-AKT-NF-κB pathway was activated by lincRNA-p21, which was then reversed by the Tβ4 administration. After the mice treated by insulin-like growth factor-1 (IGF-1) (the activator of PI3K-AKT), the inhibitory effect of Tβ4 on activated the PI3K-AKT-NF-κB pathway was abrogated. Besides, IGF-1 abolished the protective effects of Tβ4 on hepatic apoptosis and fibrosis induced by lincRNA-p21. Therefore, Tβ4 reversed. lincRNA-p21-mediated liver injury through inhibiting PI3K-AKT-NF-κB pathway. Tβ4 may be a promising drug for fibrosis therapy.

Background Early-life stress increases the risk for posttraumatic stress disorder. However, the epigenetic mechanism of early-life stress-induced susceptibility to posttraumatic stress disorder in adulthood remains unclear. Methods Rat pups were exposed to maternal deprivation during postnatal days 1 to 14 for 3 hours daily and treated with the DNA methyltransferase inhibitor zebularine, L-methionine, or vehicle 7 days before contextual fear conditioning, which was used as a second stress and to mimic the reexperiencing symptom of posttraumatic stress disorder in adulthood. Long-term potentiation, dendritic spine density, DNA methyltransferase mRNA, Reelin gene methylation, and Reelin protein expression in the hippocampal CA1 were measured. Results Maternal deprivation enhanced contextual fear memory in adulthood. Meanwhile, maternal deprivation decreased DNA methyltransferase mRNA and Reelin gene methylation in the hippocampal CA1 on postnatal days 22 and 90. Reelin protein expression was increased in the hippocampal CA1 following contextual fear conditioning in adulthood. Furthermore, compared with rats that experienced maternal deprivation alone, rats also exposed to contextual fear conditioning showed an enhanced induction of hippocampal long-term potentiation and increased dendritic spine density in the hippocampal CA1 following contextual fear conditioning in adulthood. Zebularine pretreatment led to an enhancement of contextual fear memory, hypomethylation of the Reelin gene, and increased Reelin protein expression in adult rats, while L-methionine had the opposite effects. Conclusions Maternal deprivation can epigenetically program second-hit stress-induced Reelin expression and enhance the susceptibility to contextual fear memory in adulthood. These findings provide a new framework for understanding the cumulative stress hypothesis.

The nitrogen isotope composition (δ15N) of plants in arid and semiarid grasslands is affected by environmental factors, especially water availability. Nevertheless, it is unclear whether the response of δ15N to water availability differs between C3 and C4 photosynthetic pathways. We investigated plant δ15N of coexisting C3 and C4 species as a function of aridity along a 3200 km aridity gradient across the arid and semi-arid grasslands of northern China. Aridity was positively correlated with plant δ15N values in both C3 and C4 plants and also in the entire plant community, whereas soil bulk δ15N values increased first and then decreased along the aridity gradient. The N uptake by C4 plants appeared to be more affected by competition pressure of neighboring plants and soil microbes than for C3 plants along the transect. The decoupled relationship between plant and soil δ15N values indicated that variations in vegetation and soil δ15N values were driven by differential biogeochemical processes, while different soil N sources were used for plant growth along the climatic gradient. The advantage of C3 plants in the use of N may counteract the competitive advantage that C4 plants have over C3 plants due to their higher water use efficiency under drier conditions. These findings can help understand why C4 plants do not completely replace C3 plants in drier environments despite their higher water use efficiency.

Semicarbazide (SEM) is a by-product of azodicarbonamide used to improve the properties of the plastic seals of the glass jar lids of the canned food such as baby food. This work aimed to evaluate the effect of semicarbazide (SEM) on the morphology of testicular seminiferous tubules of juvenile albino rat. Twenty juvenile male albino rats aged 4 weeks were divided into two main groups: group I (control), group II (treated with SEM 40 mg/kg oral daily for 4 weeks). Specimens from the testes were processed for different histological examinations, histochemical staining with Periodic Acid Schiff (PAS) and immunohistochemical study using antibodies against Bcl-2 was carried out in addition to morphometrical and statistical analysis. SEM-treated group showed some vacuolated spermatogenic and Sertoli cells, discontinuity of germinal epithelium, some exfoliated spermatogenic cells in the lumen in addition to focal loss of the basement membrane. A statistically significant decrease in both mean epithelial height and area percentage was recorded in group II. A statistically significant decrease of PAS reaction of the basement membrane was observed. A statistically significant decrease in Bcl-2 positive cytoplasmic immunoreaction in cells of seminiferous tubules was detected. Electron microscopic examination revealed swollen mitochondria, dilated rough endoplasmic reticulum, vacuolated cytoplasm and areas of cytoplasmic loss in spermatogenicand Sertoli cells. The nuclei of some primary spermatocytes and spermatids appeared dark and shrunken or fragmented. Thickened basement membrane with collagen deposition was detected. It could be concluded that SEM causes significant structural changes in juvenile seminiferous tubules of rat testis.So, it is recommended to use alternative safe substance in the sealing process of glass jar lids.

We realize that an optomechanical system is not only able to measure angular velocity, but also simultaneously estimate position of the corresponding rotation axis. To implement the simultaneous estimation, we first propose a multiparameter estimation scheme through a system that consists of two optomechanical subsystems. The angular velocity and rotation-axis position are jointly sensed by tested mass and then estimated by radiation exiting from the cavity due to optomechanical coupling. We adequately consider the nuisance angles, which arise from unexpected misalignment of the system, and cavity decay and provide the precision bound of the homodyne detection. The results that reveal a phase-sensitive effect indicate that selecting an appropriate phase can improve precision. Our scenario and the corresponding analysis provide a possibility to optimize rotation estimation.

A nickel-based single crystal superalloy containing Re and Ru was cast in a directional solidification furnace. The single crystal specimens after standard heat treatment were grit blasted with different pressures and then heat treated at 1100 °C for 4 h under vacuum condition. The evolution of recrystallized microstructure and its effect on the tensile properties at 850 and 980 °C were investigated. After heat treatment, the cellular microstructure was observed, and the thickness of the cellular recrystallization zone increases with the increase in grit blasting pressure. The appearance of the cellular structure undermines the tensile properties. Both the tensile strength and elongation decrease with increasing the thickness of the cellular structure. The recrystallized grain boundaries can act as the channels for the crack initiation and propagation during tensile test. The low bearing capacity of recrystallized layers and the local stress concentration resulting from the notch effect of cracking were the main reasons for the decrease of tensile properties.

Summary Combining nutrient dynamics (plant nutrient uptake and soil fertility) can help uncover mechanisms of shrub-grass interactions and assess the validity of the stress-gradient hypothesis, which predicts that facilitation between plants increases in stressful environments. However, how facilitation via shrub-mediated nutrient increases varies with precipitation is poorly resolved. We first synthesized a global dataset from 66 studies and evaluated how shrubs affected soil organic carbon (C) and nitrogen (N) in grasslands along a precipitation gradient. We then made new measurements in a single grassland type encroached by leguminous shrubs from the same genus (Caragana) to constrain the variations caused by combining different grassland types and shrubs traits in the meta-analysis. Specifically, we investigated how shrubs mediated N dynamics and how shrub-grass interactions varied along a precipitation gradient (147-342 mm) in a temperate steppe of China. At the global scale, leguminous shrub-mediated effects on soil nutrients increased with precipitation, while no relationship was found for non-leguminous shrub. For the field experiment, greater N and lower δ15N in Caragana compared to non-leguminous shrub (reference shrub, Salsola collina) suggested active N-fixation in Caragana. We found that Caragana enhanced N concentration and leaf quality (low C:N ratio) in neighbouring plants more on mesic sites than on xeric sites. Thus, facilitation increased via higher soil N and with decreasing environmental stress, at least along this relatively arid precipitation gradient. Our results highlight the importance of precipitation in determining the nutritional facilitation to neighbouring grasses from encroaching leguminous shrubs. Conceptual frameworks for plant facilitation may therefore need to include shrub characteristics (N-fixers vs. non-fixers) and positive effects of higher precipitation on this type of facilitation to characterize plant interactions along stress gradients. This article is protected by copyright. All rights reserved.

Objectives The aim of this study is to compare two different methods in assessment of the position of fetal conus medullaris (CM) and to explore the significance for assessment of CM. Methods This study included both normal fetuses and those with the diagnosis of fetal spinal lesions. The position of fetal CM was performed sonographically using two methods: location of CM in relation to the vertebral body (CM level) and measurement of the conus sacrum (CS) distance. Results The results showed that intra-observer and interobserver concordance was high for the two methods, both in the normal and abnormal groups. There was significant association between femur length and CS distance (R2 = 0.917) and between gestational age and CS distance (R2 = 0.892). Conclusions We propose the combined use of CM level location and CS distance measurement for the prenatal diagnosis of fetal spinal lesions for complementary needs.

Objective: To study the protective effect of resveratrol on secondary lung injury in intestinal ischemia reperfusion and its effect on P38MAPK pathway. Methods: Adult male SPF SD rats were selected and divided into control group, I/R group, Res-L group, Res-M group and Res-H group, the small intestinal ischemia reperfusion model was made, and Res-L group, Res-M group and Res-H group were given 5.0 mg/kg, 10.0 mg/kg and 15.0 mg/kg resveratrol for intervention. The contents of P38MAPK pathway molecules as well as downstream apoptotic molecules, inflammatory factors and oxidative stress products in the lung were detected. Results: P38MAPK, MAPKK, MAPKKK, Fas, FasL, caspase-8, caspase-9, NF-kB, TNF-α and IL-1β expression as well as ROS and MDA contents in lung tissue of I/R group were significantly higher than those of control group; P38MAPK, MAPKK, MAPKKK, Fas, FasL, caspase-8, caspase-9, NF-kB, TNF-α and IL-1β expression as well as ROS and MDA contents in lung tissue of Res-L group, Res-M group and Res-H group were significantly lower than those of I/R group. Conclusion: Resveratrol can inhibit the function of P38MAPK pathway to reduce apoptosis, inflammation and oxidative stress, and then protect the secondary lung injury induced by intestinal ischemia reperfusion.

The microstructures of low angle boundaries (LABs) of a third generation single crystal superalloy DD9 in as-cast state and after different heat treatment processes were studied by optical microscopy (OM) and field emission scanning electron microscopy (FESEM). The results showed that the as-cast LABs of DD9 alloy consisted of rod-like and bulk γ' phases with γ matrix between them, and there were eutectic γ-γ' precipitating at the LABs, as well as small amounts of discrete distribution of carbides. The γ' phase locateed at the grain boundaries was larger than that distributed on both sides of the grain boundaries. After the solution heat treatment, as-cast eutectic γ-γ' at LABs dissolved completely, and rod-like γ' phase was still found at some LABs. Meanwhile, the LABs were inclined to be straight compared to the as-cast state. The primary aging heat treatment made γ' phase at the LABs dissolved completely, and the secondary aging heat treatment resulted little change in the morphology of the LABs. Thus, the effect of the primary aging heat treatment on the microstructures of the LABs was greater than that of the secondary aging heat treatment.

To theoretically evaluate three widely used second generation single crystal superalloys-PWA1484, ReneN5 and DD6, the alloy densities, phase graphs, TCP contents, d-electron energy, and creep rupture lives were calculated, and the calculation results were analyzed combined with actual data. Results showed that among the three alloys, PWA1484 had the greatest density, secondly was DD6, and ReneN5’s density was the lowest. The PWA1484 alloy was most likely to precipitate TCP due to its highest d-orbital energy level; the ReneN5 alloy had a medium d-orbital energy level, but its high Cr content induced it to precipitate the most TCP types; the DD6 alloy had the least chance to precipitate TCP phases because of its lowest d-orbital energy level as well as lowest Cr content. It is concluded that thermodynamic calculation had the ability to simulate TCP types and TCP content at steady states, while d-orbital energy concept was capable of exhibiting the alloys in sequence of TCP precipitation potential. Mere thermodynamic calculation will lead to comparatively conservative results, including more TCP types, higher TCP contents and lower rupture lives. Analyzing the thermodynamic and d-orbital energy calculations comprehensively, it can be considered that the DD6 alloy has the most stable microstructure among the three single crystal superalloys.