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Pseudomonas plecoglossicida is a Gram-negative aerobic bacterium that causes high mortality and serious economic losses in some commercial marine fish. Expression of secY was found to be significantly upregulated at 18 °C compared to 28 °C by RNA-seq and qRT-PCR. All five tested recombinant vectors (pCM130/tac + shRNA) significantly reduced secY mRNA levels in P. plecoglossicida. The recombinant vector encoding shRNA-1165 exhibited the best gene-silencing efficiency, 82.4% and was used to create an RNAi strain for further studies. Compared with the wildtype strain, infections of Larimichthys crocea with the RNAi strain resulted in a 2-day delay in onset time and a 35% reduction in mortality, as well as the alleviation of spleen symptoms. The spleens of L. crocea infected by the wild type or RNAi strain of P. plecoglossicida were subjected to dual RNA-seq at 2 dpi. Compared with the wildtype strain, infection of P. plecoglossicida with the RNAi strain resulted in significant changes in the transcriptomes of both host and pathogen. KEGG analysis showed that the complement and coagulation cascade and the Toll-like receptor signalling pathway were the most enriched host pathways. In the pathogen, genes of the “Sec secretion system” were significantly downregulated. This downregulation of “Sec secretion system” genes hindered the secretion of bacterial proteins and reduced the virulence of P. plecoglossicida. Thus, it was easier for L. crocea to clear the RNAi strain of P. plecoglossicida, and the immune response was similarly reduced. The results indicated that secY was a virulence gene of P. plecoglossicida and played roles in the host-pathogen interactions of L. crocea and P. plecoglossicida.

As an important pathogen in aquaculture, Pseudomonas plecoglossicida has caused heavy losses. The expression of an ABC transporter gene-L321_23611 of P. plecoglossicida at 18 °C was found significant higher than those at 28 °C by RNA-seq and qRT-PCR. RNAi significantly reduced the content of L321_23611 mRNA in P. plecoglossicida with a maximal decrease of 89.2%. Compared with the wild type strain, the infection of L321_23611-RNAi strain resulted in the reduction in mortality and the onset time delay of a kind of marine teleosts, Epinephelus coioides. The results of dual RNA-seq showed that the RNAi of L321_23611 resulted in a significant change in both pathogen and host transcriptome in the spleens of infected E. coioides. The result of GO and KEGG analysis from dual RNA-seq data showed both host genes of chemokine signaling pathway, coagulation and complement system, hematopoietic cell lineage pathway as well as hemoglobin complex GO term and pathogenic genes of bacterial-type flagellum-dependent cell mortality GO term and flagellar assembly, biosynthesis of amino acids and lysine biosynthesis systems pathways were mainly affected by L321_23611 gene of P. plecoglossicida. The results indicated that: 1. ABC transporter gene-L321_23611 was a virulent gene of P. plecoglossicida. 2. Both the activation of the host immune pathways and depression of pathogenic virulence-related pathways facilitated E. coioides to remove L321_23611-RNAi strain than the wild type strain of P. plecoglossicida.

Several bacteria have been defined as extracellular pathogens; however, in recent years, it has been confirmed that they have the ability to survive and escape the attack of host phagocytes, thus causing further infection. Previous studies have shown that Aeromonas hydrophila could survive in fish macrophages; however, the mechanism remains unknown. In this study, sodA and sodB of the strain A. hydrophila B11 were stable silenced by shRNA. The survival rates of intracellular sodA-RNAi and sodB-RNAi decreased by 91.8% and 74.9% and the immune escape rates decreased by about 32% and 92% respectively. At the same time, reactive oxygen species (ROS) in fish macrophages that phagocytosed sodA-RNAi and sodB-RNAi increased by 40% and 32.6%, respectively, compared to those of macrophages that phagocytosed the wild-type strain. Compared to sodA, the expression of sodB predominates in A. hydrophila without oxidative stress; however, when exposed to oxidative stress, the magnitude of up-regulation of sodA expression is significantly higher than that of sodB. With increased of methyl viologen concentration, the survival rates of sodA-RNAi and sodB-RNAi were significantly decreased. The expressions of sodA and sodB did not affect the growth of A. hydrophila without oxidative stress, but the inhibition of sodA and sodB expression led to a slight decrease in bacterial growth under oxidative stress. These results indicated that (1) sodA and sodB play an important role in the process of bacterial resistance to ROS damage in host phagocytic cells, allowing them to survive or even escape fish macrophages; (2) the sodB expression was dominant in A. hydrophila without oxidative stress, the sodA expression was up-regulated more significantly under oxidative stress, and sodA and sodB contributed equally to the process of bacterial resistance to ROS; (3) sodA and sodB complement each other and cooperate in the process of intracellular survival of bacteria to protect against ROS damage.

Active exercise for upper limb training has been widely used to improve hemiplegic upper limb function, and its effect may be boosted by extrinsic visual feedback. The passive movement of the hemiplegic upper limb is also commonly used. We conducted a functional near-infrared spectroscopy experiment to compare cortical activation during the following three conditions: active left upper limb movement (on the hemiplegic sides in stroke patients), with or without extrinsic motor performance visual feedback (LAV, LAnV), and passive left upper limb movement (hemiplegic sides in stroke patients) (LP) in stroke patients and healthy controls. Twenty patients with right hemispheric stroke and 20 healthy controls were recruited for this study. Hemodynamic changes were detected during left upper limb movements (on the hemiplegic sides in stroke patients) under the above three conditions in the sensorimotor cortex (SMC), supplementary motor area (SMA), and premotor cortex (PMC). There was no significant difference in the level of cortical activation between patients with stroke and healthy subjects during the three conditions. Both the LAV and LAnV induced significantly higher activation in the contralateral SMA and PMC than in the LP. Extrinsic visual feedback led to additional activation in the contralateral PMC and SMA, but this was not statistically significant. Our study indicates that active upper-limb movement appears to induce higher cortical activation than that elicited by passive movement in both stroke patients and the healthy population. Extrinsic motor performance in the form of visual feedback provided during active movement may facilitate sensorimotor areas over the contralateral hemisphere.

Based on the free volume, shear transformation zone and percolation theory, a new percolation model has been established to investigate the ductile-brittle transition in amorphous alloys. Taking the binary Cu25Zr75 amorphous alloy for example, the influence of the free volume concentration and flow unit dispersity on its percolation threshold value was analyzed. The results show that the concentration of flow units reach a critical value when the ductile-brittle transition occurs in the Cu25Zr75 amorphous alloy, and this critical value is independent of the concentration of the free volume but dependent on the dispersity of flow units. Furthermore, the percolation threshold values of La-, Zr-, Cu-, Pd-, Fe-, Sr- and Tm-based amorphous alloys were also calculated, a percolation threshold value of ~0.516 for ductile-brittle transition in these amorphous alloys was obtained. Therefore, our analysis results suggest that ~0.516 appears to be a universal percolation threshold value for ductile-brittle transition in amorphous alloys.

To improve the performance of organic Rankine cycle (ORC) system, this paper proposes to replace the electric working fluid pump with multi-stage gas-liquid booster pump which is driven by high pressure gas generated in evaporator of ORC system. This pump consists of four gas-liquid booster pumps. The working principle of gas-liquid booster pump and multi-stage gas-liquid booster pump are introduced respectively. By using high pressure air as driving force and water as pressurized working fluid, the performance of multi-stage gas-liquid booster pump is tested experimentally. The experimental results of this study mainly consist of two parts: the first part focuses on the pump performance with various pressure at pump inlet and outlet while valve at pump inlet is completely open; the second part focuses on various valve open ratio at pump inlet which is operated at fixed inlet and outlet pressure of 1.8 MPa and 0.15 MPa. The results show that the pump conversion efficiency decreases with the increase of inlet pressure and the decrease of outlet pressure. The maximum conversion efficiency, volume flow rate of water and volume flow rate of high pressure air are 0.72, 0.55 L/s and 0.42 L/s respectively. When the pump is operated at different valve open ratio, the volume flow rate of water and high pressure air decreases with the decrement of valve open ratio. In addition, the conversion efficiency almost maintains identical under different valve open ratio.

The experimental and theoretical researches have been carried out to get the flow boiling heat transfer characteristics of carbon dioxide (CO2 or R744) as a refrigerant in horizontal mini-channel. Based on infrared thermal imaging tests and experimental studies on heat transfer coefficients, the heat transfer coefficients and dryout characteristics of CO2 are analyzed qualitatively and quantitatively in following conditions: Heat flux: 2~35 kW m-2, Mass flux: 50~1350 kg m-2 s-1, saturation temperature: −10~15 °C, mini-channel inner diameter: 1 mm and 2 mm. Primary conclusions can be drawn from the results of the experiments: The increase of heat flux enhances the nucleate boiling heat transfer of the refrigerant inside mini-channel, which leads to the remarkable increase of heat transfer coefficient. But it speeds up the process of dryout. It also has a certain influence on vapor qualities of dryout at both the starting and the ending stage. The effect of mass flux on heat transfer enhancement depends on the dominant heat transfer mode in the tube. With the increase of mass flow rate, the vapor quality at the start of dryout has a decreasing trend. But the heat transfer coefficient increases at the end of dryout process or even after dryout process; the heat transfer coefficient does not vary monotonically with the saturation temperature: when the saturation temperature is high and even close to CO2's critical temperature, the heat transfer coefficient increases with the increase of saturation temperature; when the saturation temperature is low, the heat transfer coefficient increases with the decrease of saturation temperature. Besides, during the heat transfer process, the dryout vapor quality falls monotonically with the increase of saturation temperature. It is reasonable to conclude that dryout characteristics have significant influence on heat transfer coefficient. Fang correlation that predicts the heat transfer coefficient of CO2 is in good agreement with the experimental data, which has a mean absolute deviation of 15.7%, and predicts 71.98% of the entire database within ±20% and 86.84% of the entire database within ±30%.

This paper presents an experimental and theoretical investigation on two-phase flow boiling heat transfer with carbon dioxide (CO 2 or R744) as the refrigerant in horizontal small diameter tube at low temperature. The experimental data were obtained in the following condition, the heat flux is 7.5–30 kW/m 2 ; the mass flow rate is 300–600 kg/m 2 s; the saturation temperature is 233–273 K; the test section is made of stainless steel tubes whose inner diameters are 0.6 and 1.5 mm. The experimental results show that heat transfer coefficient increases with the increase of mass flow rate, but decreases with the increase of tubes’ inner diameter and saturation temperature, the boiling heat transfer of CO 2 has a greater effect on nucleate boiling and highly depends on heat flux. The comparative study indicates that: during the existed flow boiling heat transfer model, the model which has the best prediction accuracy presented with 79.8% of predicted points within ±30% and 21.8% mean deviation before the dryout phenomenon happened, while it was only 18.4% and 59.9% after the dryout phenomenon happened.

The heat and mass transfer characteristics for fin-and-tube heat exchangers with low environmental pressures have been experimentally investigated. The variation trends of the jhjh factor, jmjm factor and Lewis factor were examined in this study when environmental pressure decreases from 101.3 to 40 kPa. The errors caused by non-unit Lewis factor when calculating the total heat transfer rate using the logarithmic mean enthalpy difference (LMED) method were discussed. It was found that the inlet humidity ratio for the incoming air is inversely proportional to environmental pressure under the experimental conditions. Both the heat and mass transfer performances decrease when the environmental pressure is reduced. However, the jmjm factor shows a transient rise when Re

sigX, encoding the extracytoplasmic function sigma factor SigX, was found to be highly expressed in Pseudomonas plecoglossicida at its virulent temperature. Previous RNA-seq analysis also revealed that sigX might be a key virulence gene, which could affect the Epinephelus coioides immune response against P. plecoglossicida. Despite the necessity of sigX for virulence in P. plecoglossicida, how sigX senses and response to temperature changes, and how sigX regulates P. plecoglossicida virulence remain unclear. To illuminate these, we initially analyzed the promoter regions of the sigX and found the presence of a putative CspA box. EMSA and LacZ reporter gene analysis revealed that CspA1 is required for the expression of sigX. Consistent with a role in temperature sensing, CspA1-mediated regulation of sigX is influenced by the culture temperature. Further investigations revealed that sigX is necessary for motility and biofilm formation under virulent temperature, while cspA1 expression has been reported to be induced at virulent temperature and participate in P. plecoglossicida motility and biofilm formation regulation. Meanwhile, the intracellular survival rates and immune escape rates decreased significantly after the knockout of cspA1 and sigX. Moreover, the overlap between SigX and CspA1 regulons is very limited and only one gene is predicted to be regulated by both factors, which is identified as gabD and verified via the EMSA analysis. Together, these data suggest that CspA1 contributes to virulence in a temperature-specific manner via regulating sigX expression.

10%Cr steels are being used in steam power plant due to their excellent properties at high temperatures. Dramatically enhanced impact toughness was obtained in the welded 10%Cr rotor steel after post-weld heat treatment, increasing from 5.0 J for the as-welded material to 37.5 J after being heat treated at 730 °C. Analysis of crystallographic structure showed that the microstructure was transformed from as-welded lath martensite to tempered martensite (treated at 670 °C to 700 °C), and then to high-temperature tempered martensite (treated at over 710 °C). With the increase of treatment temperature, the fractography varied from brittle fracture to a fracture mode with both brittle and ductile fracture features. A small amount of M 7 C 3 (M = Fe, Cr) particles was found in as-welded metals, while large amounts of M 23 C 6 particles were observed in those after being treated. It is proposed that the microstructure evolution from martensitic laths in the as-welded metals to a softer ferrite matrix with the dispersion of metal carbides led to higher toughness in the post-weld heat treatment materials.

Simultaneous microarray-based transcription analysis of 4987 Anopheles stephensi midgut and Plasmodium berghei infection stage specific cDNAs was done at seven successive time points: 6, 20 and 40h, and 4, 8, 14 and 20 days after ingestion of malaria infected blood. The study reveals the molecular components of several Anopheles processes relating to blood digestion, midgut expansion and response to Plasmodium-infected blood such as digestive enzymes, transporters, cytoskeletal and structural components and stress and immune responsive factors. In parallel, the analysis provide detailed expression patterns of Plasmodium genes encoding essential developmental and metabolic factors and proteins implicated in interaction with the mosquito vector and vertebrate host such as kinases, transcription and translational factors, cytoskeletal components and a variety of surface proteins, some of which are potent vaccine targets. Temporal correlation between transcription profiles of both organisms identifies putative gene clusters of interacting processes, such as Plasmodium invasion of the midgut epithelium, Anopheles immune responses to Plasmodium infection, and apoptosis and expulsion of invaded midgut cells from the epithelium. Intriguing transcription patterns for highly variable Plasmodium surface antigens may indicate parasite strategies to avoid recognition by the mosquito's immune surveillance system.