9,942 research outputs found

    Growth process and diameter structure of Pinus tabulaeformis forest for soil and water conservation in the hilly loess region of China

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    Using stem analysis method, the biomass, growing process and diameter structure of 21-year shady and sunny slope Pinus tabulaeformis forest were investigated in hilly loess-gully region. Results showed that there were distinct difference in the indexes, tree height, diameter at breast height (DBH) and timber volume between shady and sunny slope forest. The biomass, growth status and its diameter structure of shady slope forest were greater than those in sunny slope forest. The fast-growing period of tree was from 9 to 13 years. After 13 years, the annual increment of shady slope forest was greater than that of the sunny slope forest (the annual increment of shady slope forest reached 0.26 m‱a-1, whileit was about 0.1 m‱a-1 in sunny slope forest in the 21st year).The DBH growth increment of 2 forests were reduced greatly after 13 years, but the declining degree of shady slope forest was less than the sunny slope forest. The current annual increment of shady slope forest was greater than the sunny slope forest after 17 years. There was little difference in the increment of 2 timber production before 13 years. But the increment of shady forest was greater than the sunny forest after 13 years (in the 21styear, the annual increment was 0.0023 m3 in shady slope, but in sunny slope it was only 0.0015 m3). The summit of DBH distribution curve was both partial to left, while the skewness (SK was 0.75) of shadyforest was lower than that of the sunny forest (SK was 1.03) and kurtosis (K was 1.05) of shady forest was higher than that of sunny forest (K was 0.94). The results indicated the density structure of sunny slope forest was greater than shady slope forest

    Polymorphism and association of microsatellite SJ01 with birth weight and early growth traits in pigs

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    Myostatin is a negative regulator of animal skeletal muscle development and SJ01 is a microsatellite locus flanking porcine myostatin gene. In the present study, the polymorphism of microsatellite SJ01 in three pig populations, that is, Duroc (n = 420), Yorkshire (n = 414) and Landrace (n = 119), were investigated, and its associations with birth weight and early growth traits were analyzed. The results indicated that genotype BB was predominant in Yorkshire pigs and allele B was predominant in both Yorkshire and Landrace pigs, whereas allele A was more prevalent in Duroc pigs. Among the three pig breeds, Duroc population had the highest heterozygosity and deviated from Hardy-Weinberg equilibrium (P < 0.05). The average daily gain from 28 d to 70 d in Yorkshire pigs and the body weight at 70 d in Landrace pigs were significantly different between SJ01 genotypes (P < 0.05). These resultssuggest that microsatellite SJ01 is a potential DNA marker for early growth trait selection in Yorkshire and Landrace pigs as well as for refining QTL for early growth traits on SSC15

    Spin Hall effect in the kagome lattice with Rashba spin-orbit interaction

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    We study the spin Hall effect in the kagom\'{e} lattice with Rashba spin-orbit coupling. The conserved spin Hall conductance σxys\sigma_{xy}^{s} (see text) and its two components, i.e., the conventional term σxys0\sigma_{xy}^{s0} and the spin-torque-dipole term σxysτ\sigma_{xy}^{s\tau}, are numerically calculated, which show a series of plateaus as a function of the electron Fermi energy Ï”F\epsilon_{F}. A consistent two-band analysis, as well as a Berry-phase interpretation, is also given. We show that these plateaus are a consequence of the various Fermi-surface topologies when tuning Ï”F\epsilon_{F}. In particular, we predict that compared to the case with the Fermi surface encircling the Γ\mathbf{\Gamma} point in the Brillouin zone, the amplitude of the spin Hall conductance with the Fermi surface encircling the K\mathbf{K} points is twice enhanced, which makes it highly meaningful in the future to systematically carry out studies of the K\mathbf{K}-valley spintronics.Comment: 7 pages, 3 figures. Phys. Rev. B (in press

    Pressurized Calcium Looping in the Presence of Steam in a Spout-Fluidized-Bed Reactor with DFT Analysis

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    Calcium looping is a high-temperature solid-looping process for CO2 capture, exploiting cyclical carbonation of CaO. Previous work investigating the effects of steam on the carbonation reaction has produced conflicting results, with the majority of work conducted using thermogravimetric analyzers (TGA). Here, pressurized carbonation kinetics in the presence of steam in a 3 kWe pressurized spout-fluidized bed reactor, gives a rigorous insight into the effects of steam. Pseudo-intrinsic kinetics were determined using an effectiveness factor model along with activation energies and kinetic expressions. The mechanism in which steam promotes CO2 adsorption on the surface of CaO was investigated using density functional theory (DFT). The molecular-scale changes on the CaO surface owing to the presence of steam compared to the base case of CO2 adsorption on a ‘clean’ (without steam) surface were simulated with the Cambridge Serial Total Energy Package (CASTEP) software. The results suggest that steam promotes CO2 adsorption via the formation of surface OH groups on the CaO surface

    Study on the serum oxidative stress status in silicosis patients

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    To determine whether oxidative-stress damage play an important role in the mechanism of silicosis, the oxidative stress parameters were investigated in silicosis patients and controls group. 128 silicosis patients and 130 healthy controls were included. The serum superoxide dismutase (SOD) activity and the levels of malonyldialdehyde (MDA) and glutathione (GSH) were analyzed. The levels of GSH and MDA in silicosis patients were significantly higher than those of the controls group. SOD activity was higher in the silicosis group than that in the controls (p &lt; 0.05) except for III stage. None of the 3 variables examined were associated with the age among both the controls and silicosis patients. The GSH level and SOD activity significantly declined over a prolonged disease period, while MDA levels remained largely unaffected by the disease duration. These results confirmed the role of oxidative stress in the mechanism of silicosis. Therefore, effective antioxidant therapy for inhibiting oxidative stress may be a therapeutic option in silicosis.Key words: Silica, silicosis, superoxide dismutase, glutathione, malondialdehyde

    Genome-wide analysis of the nucleotide binding site leucine-rich repeat genes of four orchids revealed extremely low numbers of disease resistance genes

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    Orchids are one of the most diverse flowering plant families, yet possibly maintain the smallest number of the nucleotide-binding site-leucine-rich repeat (NBS-LRR) type plant resistance (R) genes among the angiosperms. In this study, a genome-wide search in four orchid taxa identified 186 NBS-LRR genes. Furthermore, 214 NBS-LRR genes were identified from seven orchid transcriptomes. A phylogenetic analysis recovered 30 ancestral lineages (29 CNL and one RNL), far fewer than other angiosperm families. From the genetics aspect, the relatively low number of ancestral R genes is unlikely to explain the low number of R genes in orchids alone, as historical gene loss and scarce gene duplication has continuously occurred, which also contributes to the low number of R genes. Due to recent sharp expansions, Phalaenopsis equestris and Dendrobium catenatum having 52 and 115 genes, respectively, and exhibited an "early shrinking to recent expanding" evolutionary pattern, while Gastrodia elata and Apostasia shenzhenica both exhibit a "consistently shrinking" evolutionary pattern and have retained only five and 14 NBS-LRR genes, respectively. RNL genes remain in extremely low numbers with only one or two copies per genome. Notably, all of the orchid RNL genes belong to the ADR1 lineage. A separate lineage, NRG1, was entirely absent and was likely lost in the common ancestor of all monocots. All of the TNL genes were absent as well, coincident with the RNL NRG1 lineage, which supports the previously proposed notion that a potential functional association between the TNL and RNL NRG1 genes

    The role of metabolic remodeling in macrophage polarization and its effect on skeletal muscle regeneration

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    Macrophages are crucial for tissue homeostasis. Based on their activation, they might display classical/M1 or alternative/M2 phenotypes. M1 macrophages produce pro-inflammatory cytokines, reactive oxygen species (ROS), and nitric oxide (NO). M2 macrophages upregulate arginase-1 and reduce NO and ROS levels; they also release anti-inflammatory cytokines, growth factors, and polyamines, thus promoting angiogenesis and tissue healing. Moreover, M1 and M2 display key metabolic differences; M1 polarization is characterized by an enhancement in glycolysis and in the pentose phosphate pathway (PPP) along with a decreased oxidative phosphorylation (OxPhos), whereas M2 are characterized by an efficient OxPhos and reduced PPP. Recent Advances: The glutamine-related metabolism has been discovered as crucial for M2 polarization. Vice versa, flux discontinuities in the Krebs cycle are considered additional M1 features; they lead to increased levels of immunoresponsive gene 1 and itaconic acid, to isocitrate dehydrogenase 1-downregulation and to succinate, citrate, and isocitrate over-expression

    Analysis of the cyanobacterial hydrogen photoproduction process via model identification and process simulation

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    Cyanothece sp. ATCC 51142 is considered a microorganism with the potential to generate sustainable hydrogen in the future. However, few kinetic models are capable of simulating different phases of Cyanothece sp. ATCC 51142 from growth to hydrogen production. In the present study four models are constructed to simulate Cyanothece sp. batch photoproduction process. A dynamic optimisation method is used to determine parameters in the models. It is found that although the piecewise models fit experimental data better, large deviation can be induced when they are used to simulate a process whose operating conditions are different from the current experiments. The modified models are eventually selected in the present study to simulate a two-stage continuous photoproduction process. The current simulation results show that a plug flow reactor (PFR) shows worse performance compared to a continuous stirred-tank reactor (CSTR) in the current operating conditions since it lowers the total hydrogen production. The finding is that nitrate and oxygen concentration change along the direction of culture movement in PFR, and hydrogen is only generated in the zone where both of them are low. The reactor area thereby is not well utilised. Additionally, as hydrogen production rate is primarily influenced by biomass concentration, which increases initially and decreases eventually along the direction of culture movement, the overall hydrogen production rate in a PFR may be lower than that in a CSTR. Finally, in this study fed-batch photoproduction processes are proposed containing only one photobioreactor based on the current simulation.Solar Hydrogen Project was funded by the UK Engineering and Physical Sciences Research Council (EPSRC), Project reference EP/F00270X/1. The author E.A. del Rio-Chanona funding by CONACyT Scholarship No. 522530 scholarship from the Secretariat of Public Education and the Mexican government.This is the final published version. It first appeared at http://www.sciencedirect.com/science/article/pii/S0009250915000883#

    Modelling of light and temperature influences on cyanobacterial growth and biohydrogen production

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    Dynamic simulation is a valuable tool to assist the scale-up and transition of biofuel production from laboratory scale to potential industrial implementation. In the present study two dynamic models are constructed, based on the Aiba equation, the improved Lambert–Beer's law and the Arrhenius equation. The aims are to simulate the effects of incident light intensity, light attenuation and temperature upon the photo-autotrophic growth and the hydrogen production of the nitrogen-fixing cyanobacterium Cyanothece sp. ATCC 51142. The results are based on experimental data derived from an experimental setup using two different geometries of laboratory scale photobioreactors: tubular and flat-plate. All of the model parameters are determined by an advanced parameter estimation methodology and subsequently verified by sensitivity analysis. The optimal temperature and light intensity facilitating biohydrogen production in the absence of light attenuation have been determined computationally to be 34 °C and 247 ÎŒmol m− 2 s− 1, respectively, whereas for cyanobacterial biomass production they are 37 °C and 261 ÎŒmol m− 2 s− 1, respectively. Biomass concentration higher than 0.8 g L− 1 is also demonstrated to significantly enhance the light attenuation effect, which in turn inducing photolimitation phenomena. At a higher biomass concentration (3.5 g L− 1), cyanobacteria are unable to activate photosynthesis to maintain their lives in a photo-autotrophic growth culture, and biohydrogen production is significantly inhibited due to the severe light attenuation.The author D. Zhang gratefully acknowledges the support from his family. The author P. Dechatiwongse is supported by a scholarship from the Royal Thai Government, Thailand, and his project, Solar Hydrogen Project, was funded by the UK Engineering and Physical Sciences Research Council (EPSRC), project reference EP/F00270X/1. Author E. A. del Rio-Chanona is funded by CONACyT scholarship No. 522530 from the Secretariat of Public Education and the Mexican government. The authors wish to thank Mr. Fabio Fiorelli for his invaluable advice and support during the preparation of this work.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.algal.2015.03.01

    Pan-African metamorphic and magmatic rocks of the Khanka Massif, NE China: Further evidence regarding their affinity

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    The Khanka Massif is a crustal block located along the eastern margin of the Central Asian Orogenic Belt (CAOB) and bordered to the east by Late Jurassic-Early Cretaceous circum-Pacific accretionary complexes of the Eastern Asian continental margin. It consists of graphite-, sillimanite- and cordierite-bearing gneisses, carbonates and felsic paragneisses, in association with various orthogneisses. Metamorphic zircons from a sillimanite gneiss from the Hutou complex yield a weighted mean 206Pb/ 238U age of 490 ± 4 Ma, whereas detrital zircons from the same sample give ages from 934-610 Ma. Magmatic zircon cores in two garnet-bearing granite gneiss samples, also collected from the Hutou complex, yield weighted mean 206Pb/ 238U ages of 522 ± 5 Ma and 515 ± 8 Ma, whereas their metamorphic rims record 206Pb/ 238U ages of 510-500 Ma. These data indicate that the Hutou complex in the Khanka Massif records early Palaeozoic magmatic and metamorphic events, identical in age to those in the Mashan Complex of the Jiamusi Massif to the west. The older zircon populations in the sillimanite gneiss indicate derivation from Neoproterozoic sources, as do similar rocks in the Jiamusi Massif. These data confirm that the Khanka Massif has a close affinity with other major components of the CAOB to the west of the Dun-Mi Fault. Based on these results and previously published data, the Khanka Massif is therefore confirmed as having formed a single crustal entity with the Jiamusi (and possibly the Bureya) massif since Neoproterozoic time. Copyright © Cambridge University Press 2010.published_or_final_versio
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