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Glutamate excitotoxicity in cerebral ischemia/reperfusion is an important cause of neurological damage. The aim of this study was to investigate the mechanism of Na+, K+-ATPase (NKA) involved in l ow concentration of ouabain (Oua, activating NKA)-induced protection of rat cerebral ischemia-reperfusion injury. The 2,3,5-triphenyltetrazolium chloride (TTC) staining and neurological deficit scores (NDS) were performed to evaluate rat cerebral injury degree respectively at 2 h, 6 h, 1 d and 3 d after reperfusion of middle cerebral artery occlusion (MCAO) 2 h in rats. NKA α1/α2 subunits and glutamate transporter-1 (GLT-1) protein expression were investigated by Western blotting. The cerebral infarct volume ratio were evidently decreased in Oua group vs MCAO/R group at 1 d and 3 d after reperfusion of 2 h MCAO in rats (*p ＜ 0.05 ). Moreover, NDS were not significantly different (p ＞ 0.05 ). NKA α1 was decreased at 6 h and 1 d after reperfusion of 2 h MCAO in rats, and was improved in Oua group. However, NKA α1 and α2 were increased at 3 d after reperfusion of 2 h MCAO in rats, and was decreased in Oua group. GLT-1 was decreased at 6 h, 1 d and 3 d after reperfusion of 2 h MCAO in rats, and was improved in Oua group. These data indicated that l ow concentration of Oua could improve MCAO/R injury through probably changing NKA α1/α2 and GLT-1 protein expression, then increasing GLT-1 function and promoting Glu transport and absorption, which could be useful to determine potential therapeutic strategies for patients with stroke. Low concentration of Oua improved rat MCAO/R injury via NKA α1/α2 and GLT-1.

Osteosarcoma is a kind of bone tumor with an extremely high malignant degree and often occurs in adolescents. Mesenchymal stem cells are believed to play an important role in the microenvironment of osteosarcoma, but whether they promote or inhibit the development of osteosarcoma is controversial. In this study, the coexpression of mesenchymal stem cells (MSCs) with osteosarcoma cell MG63 was used to explore the effect of MSCs on MG63. We found that co-culture of MSCs with MG63 did not affect the proliferation, invasion, and migration of MG63 cells, nor did it significantly affect the epithelial- and glial-mesenchymal transformation of MG63 cells. Therefore, in this study, we obtained a new concept that MSCs neither promote nor inhibit the occurrence and development of osteosarcoma.

Location Yunnan province, southwest China. Methods We used the homogeneous Poisson, homogeneous Thomas, inhomogeneous Poisson, and inhomogeneous Thomas point process models to predict the effect of stochastic, dispersal and/or environmental processes respectively on the distribution of trees across ontogeny in tropical, subtropical and subalpine forests. To evaluate the relative importance of models, we compared the observed and simulated patterns of species‐area relationship and g(r) at community and species level, respectively. Results Homogeneous Thomas model was the model with the lowest AIC scores across ontogeny and forest types at community level. At species level, however, homogeneous Thomas, and inhomogeneous Thomas predicted the distribution of large and small trees respectively with lower AIC values in ALS and LJ plots. In BB plot, homogeneous Thomas model is dominant across ontogeny at the species level. Conclusions The tree communities are assembled mainly by dispersal process at community level. The relative importance of ecological processes for species distribution varied across life stages at species level suggesting that there is ontogenetic shift of ecological processes in shaping tree distribution. Using different summary statistics at both community and species levels helps to discern the different spatial structure of species and increase our appreciation of the processes underpin community assembly.

The mechanisms underlying soil organic carbon (C) dynamics during forest succession remain challenged because amount, quality, and composition of C inputs change with tree growth and species composition. Soils were collected from two stages (grassland and young secondary forest) of secondary succession after the clear-cut of primary old-growth forest due to land-use change, with a native old-growth forest (undisturbed for more than 200 years) as the reference. Soil samples were incubated for 170 days and the priming effects were quantified by one pulse addition of 13C-labeled glucose. 13C-PLFAs (phospholipid fatty acids) were analyzed to identify microbial functional groups utilizing glucose and to explore their accordance with SOM priming during succession. Soil C was primed much more strongly in young secondary forest than in grassland or old-growth forest. Priming resulted in large C losses (negative net C balance) in young-forest soil, whereas C stocks increased in grassland and old-growth forest (positive net C balance). Microbial composition assessed by PLFA and utilization of easily available organics (13C-PLFA) indicated that fungi were mainly responsible for priming in young-forest soil. Consequently, labile C released by litter decomposition and root exudation together with the availability of soil nutrients determines microbial functional groups that decompose soil organic matter during initial succession. These findings provide novel ecological connections between soil organic matter dynamics and C (de)stabilization with microbial functioning during forest succession and show that priming direction and intensity is important to distinguish soil C dynamics in young- and old-growth forests.

Metabarcoding is a widely used method for fast characterization of microbial communities in complex environmental samples. However, the selction of sequencing platform can have a noticeable effect on the estimated community composition. Here, we evaluated the metabarcoding performance of a DNBSEQ-G400 sequencer developed by MGI Tech using 16S and internal transcribed spacer (ITS) markers to investigate bacterial and fungal mock communities, as well as the ITS2 marker to investigate the fungal community of 1144 soil samples, with additional technical replicates. We show that highly accurate sequencing of bacterial and fungal communities is achievable using DNBSEQ-G400. Measures of diversity and correlation from soil metabarcoding showed that the results correlated highly with those of different machines of the same model, as well as between different sequencing modes (single-end 400 bp and paired-end 200 bp). Moderate, but significant differences were observed between results produced with different sequencing platforms (DNBSEQ-G400 and MiSeq); however, the highest differences can be caused by selecting different primer pairs for PCR amplification of taxonomic markers. These differences suggested that care is needed while jointly analyzing metabarcoding data from differenet experiments. This study demonstrated the high performance and accuracy of DNBSEQ-G400 for short-read metabarcoding of microbial communities. Our study also produced datasets to allow further investigation of microbial diversity.

To examine increases in average height among Chinese children and adolescents.The data were obtained from the China Health and Nutrition Survey conducted during the period 1989-2015. A stratified multistage cluster sampling method was utilized to select participants aged 2-22 years in each province. Linear regression was used to examine the effects of age, birth cohort, and survey period on height.A total of 15,227 males and 13,737 females were included in the final analysis. Age (A) showed a continuous effect on height. The average heights of the investigated groups increased continuously during the investigation period. By 2015, the average height of the overall group increased by 7.87 cm compared to the average height during the 1989 survey. Moreover, birth year (cohort, C) also had a stable effect on height. Using the height of individuals born in or before 1975 as a reference, the average height of each birth cohort increased in comparison to the previous birth cohort.The height of Chinese children and adolescents was affected by age, period, and cohort effects, and this effect is governed by certain rules. The age-period-cohort model can be used to analyze the trends of children's and adolescent's heights. The findings provide a scientific basis for the formulation of children's and adolescents' growth and development policies in China.

Glutamate excitotoxicity in cerebral ischemia/reperfusion is an important cause of neurological damage. The aim of this study was to investigate the mechanism of Na+, K+-ATPase (NKA) involved in l ow concentration of ouabain (Oua, activating NKA)-induced protection of rat cerebral ischemia-reperfusion injury. The 2,3,5-triphenyltetrazolium chloride (TTC) staining and neurological deficit scores (NDS) were performed to evaluate rat cerebral injury degree respectively at 2 h, 6 h, 1 d and 3 d after reperfusion of middle cerebral artery occlusion (MCAO) 2 h in rats. NKA α1/α2 subunits and glutamate transporter-1 (GLT-1) protein expression were investigated by Western blotting. The cerebral infarct volume ratio were evidently decreased in Oua group vs MCAO/R group at 1 d and 3 d after reperfusion of 2 h MCAO in rats (*p ＜ 0.05 ). Moreover, NDS were not significantly different (p ＞ 0.05 ). NKA α1 was decreased at 6 h and 1 d after reperfusion of 2 h MCAO in rats, and was improved in Oua group. However, NKA α1 and α2 were increased at 3 d after reperfusion of 2 h MCAO in rats, and was decreased in Oua group. GLT-1 was decreased at 6 h, 1 d and 3 d after reperfusion of 2 h MCAO in rats, and was improved in Oua group. These data indicated that l ow concentration of Oua could improve MCAO/R injury through probably changing NKA α1/α2 and GLT-1 protein expression, then increasing GLT-1 function and promoting Glu transport and absorption, which could be useful to determine potential therapeutic strategies for patients with stroke. Low concentration of Oua improved rat MCAO/R injury via NKA α1/α2 and GLT-1.

Environmental and dispersal-based processes have been widely investigated for the understanding of community assembly. However, the relative importance of these ecological processes across spatial scales, life history stages and forest types needs to be largely studied. We test the variability of ecological processes in shaping tree community composition across life stages and spatial scales, and in particular, the hypothesis that dispersal limitation dominates at smaller scales and early life stages, but environmental filtering at larger scales and later life stages. We used spatially explicit point process models to estimate the relative importance of environmental and dispersal processes and their combined effect on beta diversity across spatial scales and life stages in tropical and subtropical forests. These models fit the observed species distribution pattern and generated realizations of the fitted models for each species. We found that the importance of environmental and dispersal processes did not shift with life stages or vegetation types, but did with spatial scales. Dispersal provided the best explanation of large-scale patterns, but dispersal combined with environmental selection was superior for small-scale patterns. In conclusion, we confirm the importance of spatial scale for the effects and identification of community assembly mechanisms. Our results also suggest that the importance of both dispersal and environmental processes for community assembly could be pervasive across life stages and vegetation types. The generality of these findings should be tested further in different vegetation types and life stages to assess whether specific ecological processes have consistent effects on community structure across life stages and vegetation types.

Metabarcoding has become the de facto method for characterizing the structure of microbial communities in complex environmental samples. To determine how sequencing platform may influence microbial community characterization, we present a large-scale comparison of two sequencing platforms; Illumina MiSeq and a new platform DNBSEQ-G400 developed by MGI Tech. The accuracy of DNBSEQ-G400 on bacterial and fungal mock samples and compared sequencing consistency and precision between DNBSEQ-G400 and MiSeq platforms by sequencing the fungal ITS2 region from 1144 soil samples with 3 technical replicates. The DNBSEQ-G400 showed a high accuracy in reproducing mock communities containing different proportions of bacteria and fungi, respectively. The taxonomic profiles of the 1144 soil samples generated by the two DNBSEQ-G400 modes closely resembled each other and were highly correlated with those generated by the MiSeq platform. Analyses of technical replicates demonstrated a run bias against certain taxa on the MiSeq but not DNBSEQ-G400 platform. Based on lower cost, greater capacity, and less bias, we conclude that DNBSEQ-G400 is an optimal platform for short-term metabarcoding of microbial communities.IMPORTANCEExperimental steps that generate sequencing bias during amplicon sequencing have been intensively evaluated, including the choice of primer pair, polymerase, PCR cycle and technical replication. However, few studies have assessed the accuracy and precision of different sequencing platforms. Here, we compared the performance of newly released DNBSEQ-G400 sequencer with that of the commonly used Illumina MiSeq platform by leveraging amplicon sequencing of a large number of soil samples. Significant sequencing bias among major fungal genera was found in parallel MiSeq runs, which can be easily neglected without the use of sequencing controls. We emphasize the importance of technical controls in large-scale sequencing efforts and provide DNBSEQ-G400 as an alternative with increased sequencing capacity and more stable reproducibility for amplicon sequencing.

Backgroud this paper is to explore the influencing factors on utilizing physical examinations (PE) for the seasonal immigrants who moved from their home town to Sanya city in Hainan province in China during the winter . Methods A total of 1342 seasonal immigrants (aged 50 or over) were randomly selected and surveyed through a standardized questionnaire. Using an adjusted logistic regression model to identify the factors associated with the use of PE for those immigrants. Results We found the utilization rate of PE among seasonal immigrants is 26.80%. The level of education, living time, the availability of health insurance, and the attitude to the quality of health service were influencing factors( p < 0.05) . Conclusion The results imply seasonal immigrants have a low utilization rate of physical examination. To improve the availability of health insurance and the quality of health service will be helpful to keep the health of the seasonal immigrants in Sanya .

This work focuses on the organic depressant, disodium bis(carboxymethyl) trithiocarbonate (DBT), as a selective depressant in copper-molybdenum sulfide flotation separation. Micro-flotation, Zeta potential, FTIR and XPS measurements were carried out to investigate the selective depression mechanism of DBT on chalcopyrite. Zeta potential and FTIR measurements revealed that DBT had higher affinity for chalcopyrite than molybdenite and the XPS results of chalcopyrite before and after treatment with DBT further proved that DBT adsorbed on chalcopyrite surface. The investigation indicates that the mechanism of DBT adsorbing on chalcopyrite is mainly physical adsorption. Locked circuit experiments were carried out and the results showed that DBT could be considered as a cleaner option in commercial Cu-Mo flotation separation circuits.

In tropical plant communities with diverse species, many congeners are found to coexist. Do environment or biotic interactions structure the coexistence of congeners in tropical forest communities? In this paper, we aimed to disentangle the effect of environment (first-order effects) and species interactions (second-order effects) on the spatial distributions of tree species. We used a classification scheme and torus-translation to test the first-order interaction of 48 species from 17 genera in a fully mapped 20-ha dipterocarp tropical seasonal rain-forest plot in Xishuangbanna, south-west China. Then we used heterogeneous Poisson null models to reveal significant uni- and bivariate second-order interactions. The results demonstrated that (1) 34 of the 48 studied species showed a significant relation with at least one topographic variable. This confirmed that topographical heterogeneity is important for distribution of these congeners. Spatial segregation (36.6%) and partial overlap (34.8%) were the most common bivariate association types in Xishuangbanna plot, which indicated first-order effects (environment) were strong. (2) For small-scale associations, 51% saplings (1 to ≤ 5 cm) (68.8% for large trees with dbh > 5 cm) of the species showed non-significant associations. For large-scale associations, 61.6% saplings (81.2% for large trees) of the species showed non-significant associations. Lack of significant species interactions provides evidence for the unified neutral theory. In conclusion, both environment and biotic interactions structure congeneric species' coexistence in tropical seasonal rain forest in this region.

Spatial patterns in trait variation reflect underlying community assembly processes, allowing us to test hypotheses about their trait and environmental drivers by identifying the strongest correlates of characteristic spatial patterns. For 43 evergreen tree species (> 1 cm dbh) in a 20-ha seasonal tropical rainforest plot in Xishuangbanna, China, we compared the ability of drought-tolerance traits, other physiological traits, and commonly measured functional traits to predict the spatial patterns expected from the assembly processes of habitat associations, niche-overlap-based competition, and hierarchical competition. We distinguished the neighborhood-scale (0-20 m) patterns expected from competition from larger-scale habitat associations with a wavelet method. Species' drought tolerance and habitat variables related to soil water supply were strong drivers of habitat associations, and drought tolerance showed a significant spatial signal for influencing competition. Overall, the traits most strongly associated with habitat, as quantified using multivariate models, were leaf density, leaf turgor loss point (π(tlp); also known as the leaf wilting point), and stem hydraulic conductivity (r2 range for the best fit models = 0.27-0.36). At neighborhood scales, species spatial associations were positively correlated with similarity in π(tlp), consistent with predictions for hierarchical competition. Although the correlation between π(tlp) and interspecific spatial associations was weak (r2 < 0.01), this showed a persistent influence of drought tolerance on neighborhood interactions and community assembly. Quantifying the full impact of traits on competitive interactions in forests may require incorporating plasticity among individuals within species, especially among specific life stages, and moving beyond individual traits to integrate the impact of multiple traits on whole-plant performance and resource demand.

The net primary productivity (NPP) of tropical forests is a key part of the global carbon cycle. Numerous studies have estimated tropical forest NPP, yet most of them focus on how annual NPP dynamics vary over several years. Little is known about how NPP responds to long-term climatic variation at the monthly or seasonal scales. We estimated NPP at three-month intervals from 2009 to 2017 for a tropical seasonal rainforest in Xishuangbanna, Southwest China using data from >2000 dendrometer bands and litter fall traps within a 20-ha permanent forest dynamics plot. We asked which climatic factor has the greatest effect on forest NPP at the sub annual scale, and how the relationships vary with seasonality. Calculations showed that NPP ranged from 12 to 20 t ha−1 yr−1, and that forest productivity showed a slight, but insignificant increase from 2009 to 2017. NPP was significantly higher in the wet season than that in the dry season and was significantly related to precipitation only when all data were concerned. During the dry season, precipitation had a significant positive influence on NPP, but no effect during the wet season. We further identified that there was a threshold effect of precipitation on NPP. Specifically, productivity increased more rapidly when monthly precipitation below 229 mm. In summary, we conclude that periods of low rainfall strongly regulate the productivity in this tropical seasonal rainforest which could guide the management design of water use efficiency in tree based land-use system, like agroforestry ecosystems.

The degradation behavior of ethyl xanthate (EX) salt was the most widely used collector in sulfide mineral flotation and emission of flotation tailings with residual EX was harmful to environment. In this work, hydrogen peroxide (H2O2) was investigated by UV-visible spectroscopy (UV/Vis) at different pH values from 3 to 12. For pH value from 5 to 12, EX was oxidized into ethyl per xanthate (EPX) by H2O2. Then EPX was further oxidized into thiosulfate (TS) salt rather than ethyl thiocarbonate (ETC) and this step was the reaction-limited step. Then depending on pH values, TS was degraded into sulphate and carbonate salts (pH>7) or elemental sulfur (pH 3.0 during test time.

Bioleaching Xiangjiang River alkaline sediment contaminated by multiple heavy metals was investigated. Multiple metals in alkaline sediment possess significant toxicity to aquatic organisms or humans and will greatly inhibit bioleaching. The bioleaching method using autotrophic bacteria mixed with heterotrophic bacteria can solve this problem successfully. The experiment results showed that bioleaching efficiencies of Zn, Mn, Cu, and Cd were 95.2 %, 94.2 %, 90.1 %, and 84.4 %, respectively. Moreover, the changes of heavy metal concentrations in different fractions in contaminated sediment before and after bioleaching were analyzed by selective sequential extraction, and it was discovered that the main fractions of Zn, Mn, Cu and Cd after bioleaching are Fe-Mn oxide, organic associated form and a residual form. Its biotoxicity decreased greatly. The bioleaching heavy metals from sediment using autotrophic bacteria combined with heterotrophic bacteria can effectively improve the bioleaching efficiency and reduce toxicity.

The population of surface broken bonds of some typical sulfide, oxide and salt-type minerals which may belong to cubic, tetragonal, hexagonal, or orthorhombic system, were calculated. In terms of the calculation results, the cleavage natures of these minerals were analyzed, and the relationship between surface broken bonds density and surface energy was also established. The results show that the surface broken bonds properties could be used to predict the cleavage nature of most of minerals, and the predicted cleavage planes agree well with those reported in previous literature. Moreover, this work explored a rule that, surface broken bonds density is directly related to surface energy with determination coefficient ( R 2 ) of over 0.8, indicating that the former is a dominant factor to determine the latter. Therefore, anisotropic surface broken bonds density can be used to predict the stability of mineral surface and the reactivity of surface atoms.

The chemical components, dissemination characteristics and flotation behaviour of copper slag have been investigated through chemical analysis, X-ray powder diffraction (XRD), electron microscopeand flotation tests. These results show that the converter copper slag from Hubei, China, is refractory resource owing to its complex composition and mosaic relationship. Copper, iron, and other minerals are closely intergrowth in it. The electron microscope pattern and particle analysis tests demonstrate that the particles of copper are fine and unevenly disseminated in the slag. The proper grinding fineness, types of collectors and collector dosages have been determined through the flotation condition tests. The closed-circuit test is enforced by using the new machine-column joint beneficiation process. As a result, a copper concentrate grading 37.14% at a recovery of 94.75% is obtained. The test result demonstrates that this beneficiation process can treat the complex refractory copper slag effectively.

Monodominance in the tropics is often seen as an unusual phenomenon due to the normally high diversity in tropical rain forests. Here we studied Parashorea chinensis H. Wang (Dipterocarpaceae) in a seasonal tropical forest in south-west China, to elucidate the mechanisms behind its monodominance. Twenty-eight 20 × 20-m plots were established in monodominant and mixed forest in Xishuangbanna, Yunnan province. All individuals ≥1 cm stem diameter and 16 soil variables were measured. Parashorea chinensis forest had a significantly higher mean tree dbh compared with mixed forest. Diversity did not differ significantly between the two forest types. However, within monodominant patches, all diversity indices decreased with an increase in P. chinensis dominance. Floristic composition of P. chinensis forest did differ significantly from the mixed forest. These differences were associated with more fertile soils (significantly higher pH, Mn, K and lower carbon pools and C:N ratio) in the P. chinensis forest than the mixed forest. In contrast to current paradigms, this monodominant species is not associated with infertile, but with fertile soils. Parashorea chinensis seems to be especially associated with high manganese concentrations which it can tolerate, and with edaphic conditions (water, K) that allow this tall and exposed emergent species to maintain its water balance. This is in contrast with most previous studies on monodominance in the tropics that found either no effect of soil properties, or predict associations with nutrient-poor soils.

Surface energies of five different surfaces of scheelite crystal were calculated using density functional theory (DFT). Based on the calculation results, the predominantly exposed surfaces in the morphologies of scheelite crystals were predicted. {112} and {001} cleavage surfaces and {112} crystal surface are the commonly exposed surfaces, which are consistent with both previous literatures and the present experimental observations based on the XRD. Cleavage generates more easily along {112} surfaces than along {001} surfaces due to their different interlayer spacings. The surface roughness and appearance of different predominantly exposed surfaces were then investigated using AFM. The roughness of smooth {112} cleavage surface is the lowest among these three surfaces. On {001} cleavage surface, terraces are flat and separated by steps of about 10 nm in height. Subsequently, contact angle measurements were adopted to evaluate the wettability and surface energies of these surfaces. The surface energies evaluated directly correspond to the trend calculated with DFT.

Locally available resources can be shared within clonal plant systems through physiological integration, thus enhancing their survival and growth. Most epiphytes exhibit clonal growth habit, but few studies have tested effects of physiological integration (resource sharing) on survival and growth of epiphytes and whether such effects vary with species. We conducted two experiments, one on individuals (single ramets) and another on groups (several ramets within a plot), with severed and intact rhizome treatments (without and with physiological integration) on two dominant epiphytic ferns (Polypodiodes subamoena and Lepisorus scolopendrium) in a subtropical montane moist forest in Southwest China. Rhizome severing (preventing integration) significantly reduced ramet survival in the individual experiment and number of surviving ramets in the group experiment, and it also decreased biomass of both species in both experiments. However, the magnitude of such integration effects did not vary significantly between the two species. We conclude that resource sharing may be a general strategy for clonal epiphytes to adapt to forest canopies where resources are limited and heterogeneously distributed in space and time.

A negative species-genetic diversity correlation (SGDC) could be predicted by the niche variation hypothesis, whereby an increase in species diversity within community reduces the genetic diversity of the co-occurring species because of the reduction in average niche breadth; alternatively, competition could reduce effective population size and therefore genetic diversity of the species within community. We tested these predictions within a 20 ha tropical forest dynamics plot (FDP) in the Xishuangbanna tropical seasonal rainforest. We established 15 plots within the FDP and investigated the soil properties, tree diversity, and genetic diversity of a common tree species Beilschmiedia roxburghiana within each plot. We observed a significant negative correlation between tree diversity and the genetic diversity of B. roxburghiana within the communities. Using structural equation modeling, we further determined that the inter-plot environmental characteristics (soil pH and phosphorus availability) directly affected tree diversity and that the tree diversity within the community determined the genetic diversity of B. roxburghiana. Increased soil pH and phosphorus availability might promote the coexistence of more tree species within community and reduce genetic diversity of B. roxburghiana for the reduced average niche breadth; alternatively, competition could reduce effective population size and therefore genetic diversity of B. roxburghiana within community.

Decomposition of organic matter (OM) in soil, affecting carbon (C) cycling and climate feedbacks, depends on microbial activities driven by C and nitrogen (N) availability. However, it remains unknown how decomposition of various OMs vary across global supplies and ratios of C and N inputs. We examined OM decomposition by incubating four types of OM (leaf litter, wood, organic matter from organic and mineral horizons) from a decay continuum in a subtropical forest at Ailao Mountain, China with labile C and N additions. Decomposition of wood with high C:N decreased for 3.9 to 29% with these additions, while leaf decomposition was accelerated only within a narrow C:N range of added C and N. Decomposition of OM from organic horizon was accelerated by high C:N and suppressed by low C:N, but mineral soil was almost entirely controlled by high C:N. These divergent responses to C and N inputs show that mechanisms for priming (i.e. acceleration or retardation of OM decomposition by labile inputs) vary along this decay continuum. We conclude that besides C:N ratios of OM, those of labile inputs control the OM decay in the litter horizons, while energy (labile C) regulates decomposition in mineral soil. This suggests that OM decomposition can be predicted from its intrinsic C:N ratios and those of labile inputs.

This paper is concerned with the stabilization control for the offshore steel jacket platforms subject to wave-induced force. Two state feedback stabilization control schemes are proposed to reduce the vibration amplitudes of the systems. One scheme is that for the systems without actuator time-delay, a state feedback controller is designed. Compared with the nonlinear controller, both the control force and the vibration amplitudes of the systems under the state feedback controller are much reduced; and compared with the dynamic output feedback controller and the integral sliding mode controller, the required control force under the state feedback controller are significantly reduced. The other scheme is that based on the integral inequality approach, a delay-dependent state feedback controller, which can be solved by using the cone complementarity algorithm, is developed to control the systems with actuator time-delays. Compared with the state feedback controller, the delay-dependent state feedback controller is less conservative with actuator time-delays. In addition, it is capable of improving the control performance of the offshore platforms significantly, which are illustrated by simulation results.

This study presents sulfide ores with lead 0.71%, Zinc5.07% from Laos, using a grinding (grinding fineness -0.075mm, 80%). Then, the lead ores is recovered by flotation first. Second, the middling ores is returned in preferential floatation. The mixed collector is used in all flotation such as ethyl xanthogenate , butyl xanthate and SN-9.After flotation, the grade of lead concentrate is 63.63%, and a recovery is 83.26% .In addition, the grade of zinc is 56.33%,a recovery is 86.63%. It can result in obvious increase in yields of mineral processing and economic better effect in production, compared to the old technology.

Anisotropic surface broken bond densities of six different surfaces of calcite and three surfaces of fluorite were calculated. In terms of the calculated results, the commonly exposed surfaces of the two minerals were predicted and the relations between surface broken bonds densities and surface energies were analyzed. Then the anisotropic wettability of the commonly exposed surfaces was studied by means of contact angle measurement. The calculation results show that the, and surfaces for calcite and (111) for fluorite are the most commonly exposed surfaces and there is a good rectilinear relation between surface broken bond density and surface energy with correlation of determination (R2) of 0.9613 and 0.9969, respectively. The anisotropic wettability of different surfaces after immersing in distilled water and sodium oleate solutions at different concentrations can be explained by anisotropic surface broken bond densities and active Ca sites densities, respectively.

Bioleaching is an environmental friendly technology with many potential advantages such as few pollution and low energy requirement. The factors which affected the silicate-dissolving ability of Bacillus mucilaginosus Lv1-2on illite were investigated. The results showed that the optimum inoculum amount was 2%.The best carbon source and nitrogen source were glucose and (NH4)2SO4respectively. The silicon dissolution increased with the powder diameter decreased. The optimal temperature and shaking speed were 30°C and 220 rpm. The proper conditions were consistent with that of the growth of the strain,which confirmed that the strain played an important role in bioleaching.

Habitat heterogeneity and dispersal limitation are widely considered to be the two major mechanisms in determining tree species distributions. However, few studies have quantified the relative importance of these two mechanisms at different life stages of trees. Moreover, rigorous quantification of the effects of dominant tree species in determining species distributions has seldom been explored. In the present study, we tested the hypothesis that the distribution of tree species is regulated by different mechanisms at different life history stages. In particular, we hypothesised that dispersal limitation regulates the distribution of trees at early life stages and that environmental factors control the distribution of trees as they grow, because of niche differentiation resulting from environmental filtering. To test this, trees in 400-m 2 quadrats in a 20-ha plot in Xishuangbanna, southwest China were grouped into four classes on the basis of the diameter at breast height (DBH) that roughly represent different stages in the life history of trees. A neighbourhood index was computed to represent a neutral spatial autocorrelation effect. We used both biotic (dominant species) and abiotic (topography and soil) predictor variables to model the distribution of each target species while controlling for spatial autocorrelation within each of the DBH classes. To determine which factors played the largest role in regulating target species distribution, the simulated annealing method was used in model selection based on Akaike information criterion (AIC) values. The results showed that the relative importance of neutral and niche processes in regulating species distribution varied across life stages. The neutral neighbourhood index played the most important role in determining the distributions of small trees (1 cm  DBH  10 cm), and dominant species, as biotic environmental predictor variables, were the next most important regulators for trees of this size. Environmental predictor variables played the most important role in determining the distributions of large trees (10 cm  DBH). This finding builds on previous research into the relative importance of neutral and niche processes in determining species distributions regardless of life stages or DBH classes.

The degree to which variation in species distribution is predictable from topographic variation is of considerable current interest. In this paper, canonical correspondence analysis (CCA), linear regression and principal coordinates of neighbour matrices (PCNM) models were used to explain the variation in the distributions of the 13 dominant species in a 20-ha tropical rain-forest plot in China. The results showed that: (1) Tree distribution maps show that some species are mainly found in the gullies of the plot, whereas others occur on the slopes. Which indicates topographic variables are important factors for the distribution pattern of species. (2) Both linear regression and CCA results show that convexity and elevation are the most important variables effecting distribution of trees. For saplings, elevation, convexity and aspect explain 15.3%, 9.0% and 10.1% of the total variation of species abundance. For poles, elevation and convexity explain 19.3% and 11.4% respectively. However, only 5.3% of the total variation is explained for adults. (3) The PCNM results showed that topography alone explained 20%, 24% and 5% of the total variation of species abundance for saplings, poles and adults, respectively. Overall evidence for topographic control of the tropical tree distribution is strong, but the explanatory power of topographic variables was a small part of the total of variation.

This paper develops a set of tri-cone bit CAD system based on UG platform relying on using parametric design idea; studies the systematic structure and development principle of the cone bit CAD system; molds the cone, tooth and tooth slot by using the basic theory of parametric design and feature modeling corresponding to the example, and realizes the assembly of cone and tooth and virtual assembly of three cones. This system interface is simple, intuitive, easy to operate, and has good human-computer interaction and scalability and portability. This paper provides a research base for the developing a more perfect tri-cone bit CAD system on UG.

In this paper, a new classification equipment for Bauxite desiliconization is introduced, which combines Centrifugal with gravity and it can separate diaspore and slime effectively in a composite force; The flow field in the equipment was simulated by Fluent software for explaining separation process and principle; the laboratory experiments and pilot tests had been finished on this kind of device, showing that a concentrate with Al2O3 recovery of 90.64% and Al-Si ratio of 6.34 was obtained from the feed with a Al/Si ratio of 4.7 based on one stage desiliconization separation; the pilot tests show that new classification equipment for Bauxite desiliconization can increase the concentration with Al2O3 recovery by 1.59 percent and Al-Si ratio by 0.19 and degrease the Al-Si ratio of tailing by 0.39. The separation index of the new separator is better than the general separator obviously.

When the full weathered granite is regarded as highway subgrade filling material, it is restricted to the application because of its high mica content, lax construction, bad water stability, and small cohesion. For these reasons, the full weathered granite soil should be improved before using for subgrade filling, and the cement was taken as an improver in this paper. The dynamic and static characteristics of cement stabilized soils were studied systemically. It was shown from the experiment results that there is a decrease in the content of mica and clay, and an increase of quattz of the cement stabilized soils. The unconfined strength of the cement stabilized full weathered granite increases linearly with the increase in cement content. There is power function relationship between water stability coefficient and the cement content. The unconfined strength and water stability coefficient increases with degree of compaction and with age as well, while the increasing rate decrease with age. The dynamic strength of the cement stabilized full weathered granite increased with the increase of the degree of compaction and the cement content. However, as the water content increases, the dynamic strength increased first and then decreases, there is an optimum moisture content. A linear model was proposed to describe the dynamic modulus and dynamic relationship between the stress amplitude. The results can provide an important reference for engineering practice.

Dispersion experiments were conducted to study the influence of metallic cations on the dispersibility of diaspore. The reaction mechanisms were investigated based on the analysis of zeta (ζ) potential and calculations of solution chemistry and DLVO theory. The results show that the valence of cations, instead of the cation type, plays an important role in the dispersibility of diaspore. The impact of multivalent metallic cations is greater than that of monovalent cations. In the presence of Ca2+ and Mg2+, the dispersion of diaspore doesn't change in the range of pH value below 10. However, Ca2+ and Mg2+ may induce strong coagulation of particles when pH value is higher than 10. The adsorption of species of calcium and magnesium ions on diaspore can cause the compression of electric double layer, the decrease of the absolute value of zeta potential and the repulsion force between diaspore particles. The new IEP (isoelectric point) appeared at pH value of 11 may attribute to the adsorption of Mg(OH)2(s).

High density ZnO-nanorod arrays (rod length 1.59 μm) were successfully synthesized via a microwave-assisted solution-phase method using zinc chloride and ammonia solution as reactants. The influence of concentration of ammonia solution, work power, and microwave irradiation time on the morphology and size of final products was carefully investigated. The crystal structure, chemical composition and morphologies of final products were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL). The as-synthesized ZnO is composed of single crystalline and possesses three photoluminescence emissions centered at 400, 469 and 534.5 nm, respectively.