51 research outputs found
Effects of temperature on photosynthetic performance and nitrate reductase activity in vivo assay in Gracilariopsis lemaneiformis (Rhodophyta)
Gracilariopsis lemaneiformis is an economically-valued species and widely cultured in China at present. After being acclimated to different growth temperatures (15, 20, 25, and 30 degrees C) for 7 days, the relative growth rate (RGR), nitrate reductase activity, soluble protein content and chlorophyll a fluorescence of G. lemaneiformis were examined. Results show that RGR was markedly affected by temperature especially at 20 degrees C at which G. lemaneiformis exhibited the highest effective quantum yield of PSII [Y(II)] and light-saturated electron transport rate (ETRmax), but the lowest non-photochemical quenching. Irrespective of growth temperature, the nitrate reductase activity increased with the incubation temperature from 15 to 30 degrees C. In addition, the greatest nitrate reductase activity was found in the thalli grown at 20 degrees C. The value of temperature coefficient Q10 of alga cultured in 15 degrees C was the greatest among those of other temperatures tested. Results indicate that the optimum temperature for nitrate reductase synthesis was relatively lower than that for nitrate reductase activity, and the relationship among growth, photosynthesis, and nitrate reductase activity showed that the optimum temperature for activity of nitrate reductase in vivo assay should be the same to the optimal growth temperature
Increased expression of long-isoform thymic stromal lymphopoietin is associated with rheumatoid arthritis and fosters inflammatory responses
Thymic stromal lymphopoietin (TSLP) is a pleiotropic cytokine that is involved in the pathogenesis of inflammatory diseases and asthma, but the expression and biological implications of the existence of two isoforms, long TSLP (lTSLP) and short TSLP (sTSLP), in RA have yet to be elucidated. Here we report that lTSLP is the predominant TSLP isoform in RA and active RA, whereas sTSLP is the major TSLP isoform in inactive RA and healthy controls. lTSLP expression is associated with disease activity, including 28-joint Disease Activity Score (DAS28) and erythrocyte sedimentation rate (ESR), as well as proinflammatory cytokine expression, irrespective of other laboratory parameters. Importantly, lTSLP alone or combined with LPS promotes the expression of proinflammatory cytokines IL-1β, IL-6, and IL-8 in PBMCs of RA, but restrains anti-inflammatory cytokine IL-10 expression in PBMCs of RA. Furthermore, we found that STAT5 signaling is involved in lTSLP-induced inflammatory accumulation in PBMCs of RA. Therefore, these results highlight the clinical significance of lTSLP in RA pathology and inflammatory response in acute-phase disease, which may provide a therapeutic target for RA
High-level soluble expression of the functional peptide derived from the C-terminal domain of the sea cucumber lysozyme and analysis of its antimicrobial activity
Background: The sea cucumber lysozyme belongs to the family of
invertebrate lysozymes and is thought to be a key defense factor in
protecting aquaculture animals against bacterial infection. Recently,
evidence was found that the sea cucumber lysozyme exerts broad spectrum
antimicrobial action in vitro against Gram-negative and Gram-positive
bacteria, and it also has more potent antimicrobial activity
independent of its enzymatic activity. To explore the antimicrobial
role of this non-enzymatic lysozyme and model its structure to novel
antimicrobial peptides, the peptide from the C-terminal amino acid
residues 70\u2013146 of the sea cucumber lysozyme in Stichopus
japonicus (SjLys-C) was heterologously expressed in Escherichia coli
Rosetta(DE3)pLysS. Results: The fusion protein system led to
over-expression of the soluble and highly stable product, an
approximate 26 kDa recombinant SjLys-C protein (rSjLys-C). The present
study showed that rSjLys-C displayed strong antimicrobial activity
against the tested Gram-positive and Gram-negative bacteria. In
particular, the heat-treated rSjLys-C exhibited more inhibitive
activity than the native rSjLys-C. The structural analysis of SjLys-C
showed that it is a typical hydrophilic peptide and contains a
helix-loop-helix motif. The modeling of SjLys-C molecular structures at
different temperatures revealed that the tertiary structure of SjLys-C
at 100\ub0C underwent a conformational change which is favorable for
enhancing antimicrobial activity. Conclusion: These results indicate
that the expressed rSjLys-C is a highly soluble product and has a
strong antimicrobial activity. Therefore, gaining a large quantity of
biologically active rSjLys-C will be used for further biochemical and
structural studies and provide a potential use in aquaculture and
medicine
Method for Retrieving Digital Agricultural Text Information Based on Local Matching
In order to improve the retrieval results of digital agricultural text information and improve the efficiency of retrieval, the method for searching digital agricultural text information based on local matching is proposed. The agricultural text tree and the query tree are constructed to generate the relationship of ancestor–descendant in the query and map it to the agricultural text. According to the retrieval method of the local matching, the vector retrieval method is used to calculate the digital agricultural text and submit the similarity between the queries. The similarity is sorted from large to small so that the agricultural text tree can output digital agricultural text information in turn. In the case of adding interference information, the recall rate and precision rate of the proposed method are above 99.5%; the average retrieval time is between 4s and 6s, and the average retrieval efficiency is above 99%. The proposed method is more efficient in information retrieval and can obtain comprehensive and accurate search results, which can be used for the rapid retrieval of digital agricultural text information
Design and Application of Wuhan Ionospheric Oblique Backscattering Sounding System with the Addition of an Antenna Array (WIOBSS-AA)
The Wuhan Ionospheric Oblique Backscattering Sounding System with the addition of an antenna array (WIOBSS-AA) is the newest member of the WIOBSS family. It is a multi-channel radio system using phased-array antenna technology. The transmitting part of this radio system applies an array composed of five log-periodic antennas to form five beams that span an area to the northwest of the radar site. The hardware and the antenna array of the first multi-channel ionosonde in the WIOBSS family are introduced in detail in this paper. An ionospheric detection experiment was carried out in Chongyang, Hubei province, China on 16 March 2015 to examine the performance of WIOBSS-AA. The radio system demonstrated its ability to obtain ionospheric electron density information over a wide area. The observations indicate that during the experiment, the monitored large-area ionospheric F2-layer was calm and electron density increased with decreasing latitude
In situ observation of the austenite to ferrite transformation in low-carbon steels from different initial phases at defined cooling rates
An experimental investigation has been conducted with respect to the decomposition of austenite to various ferritic products from different initial phase states (molten-state of 1550 °C and solid-state of 1050 °C) and pre-defined cooling rates (1 °C/s and 10 °C/s) in a typical low-carbon steel using the confocal laser scanning microscope (CLSM). Surface morphology, microstructure, internal stress and dislocation density were analyzed. Changing the initial states from the molten to the solid state and lowering the cooling rate from 10 °C/s to 1 °C/s increased the phase transformation starting temperature. Compared with the uniform cooling condition to produce polygonal ferrite of the solid-state sample, unevenly distributed internal stresses were found from the initial molten-state sample. Additionally, high dislocation densities were observed in stress concentrated areas of the initial molten-state samples resulting in the formation of lath-like ferrite but coarse quasi-polygonal ferrite in relatively stress-free areas. Moreover, when the cooling rate was increased to 10 °C/s, the proportion of lath-like ferrite obviously increased in the molten-state and the size of the polygonal ferrite decreased in the solid-state sample due to the increasing of nucleation rate from austenite to ferrite
Comparison of the photo-acclimation potential of floating and benthic thalli of Sargassum horneri (Phaeophyta) during autumn and winter
Sargassum horneri is a foundational species and an important contributor to the floating seaweed stock along the northeastern coast of Asia. In this study, benthic and floating thalli of S. horneri were collected from Changdao Island (37 degrees 54 ' N, 120 degrees 43 ' E), Bohai Bay, China. We conducted an in-situ and an indoor experiment to study the acclimation potential in S. horneri to abiotic conditions at sea surface in autumn and winter. Both benthic and floating thalli were cultured in situ for two months (from October to December) at different depths: 0 m above sea level (masl) and 3 m below sea level (mbsl), and their growth rate, biochemical content, and photosynthetic performance were compared. During the first month of culture, the relative growth rate of floating thalli was 2-fold greater than that of benthic thalli at 0 masl. The photosynthetic rate of most thalli was significantly higher at 0 masl than at 3 mbsl. In the indoor experiments, floating and benthic thalli were exposed to high light intensity (400 mu mol photons/(m(2)center dot s) photosynthetically active radiation (PAR)) for 21 d, and their photo-acclimation capacities were compared. Under high light intensity, the two types of thalli showed low maximum quantum yield (F-v/F-m) and light utilisation efficiency (alpha) but high light saturation point (E-k). Floating thalli showed higher photosynthetic rate and photoprotective ability than benthic thalli at high light intensity. The effective quantum yield of photosystem II [Y(II)] of both types of thalli recovered after a 6-day treatment with low light intensity (40 mu mol photons/(m(2)center dot s)). These findings suggest that S. horneri is highly acclimated to the sea surface environment, which possibly contributes to its rapid accumulation and long free-floating periods at the sea surface
Simulation of Subrapid Solidification and Secondary Cooling for the Strip Casting of IF Steel
A combination of droplet solidification tester and confocal laser scanning microscope was used to simulate subrapid solidification and secondary cooling process pertinent to the strip casting. The IF steel droplet had a delamination structure and the bottom part went through sub-rapid solidification. During secondary cooling, γ/α transformation mechanism belonged to interface-controlled massive transformation and the ferrite grains grew quickly. With the increase of cooling rate, the γ/α transformation temperature decreased and the incubation period and phase transformation duration reduced. The hardness showed a slight increase due to fine-grain strengthening. With coiling temperature increasing from 600 °C to 800 °C, the grain size became larger, precipitates became coarse, and defects in grain were recovered. Consequently, the hardness decreased
Experimental and Numerical Analysis of Large-Scale Circular Concrete-Filled Steel Tubular Columns with Various Constructural Measures under High Axial Load Ratios
To investigate the effect of constructional measures (including horizontal and vertical stiffeners, rebar cages, embedded steel tubes, and cavity welded steel plates) under high axial load ratios on the seismic performance of concrete-filled steel tubular (CFST) columns, quasi-static tests for six large-scale CFST columns with various constructional measures are performed. All specimens are subjected to identical axial forces. The failure mode, hysteresis characteristics, bearing capacity, stiffness degradation, ductility, and energy dissipation of specimens are analyzed. The study shows that the horizontal stiffener delays the occurrence and severity of column base buckling, the vertical stiffener improves the bending resistance capacity and initial stiffness of the member, the rebar cage improves the ductility, and the embedded circular steel tube significantly improves the member’s bearing capacity, ductility, and energy dissipation. When an internal circular steel tube and cavity welded steel plate are applied in tandem, the section steel ratio increases by 4.42% and the bearing capacity improves by 42.72%. A finite element model is created to verify test results, and simulation results match the test results well
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