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Gasification for hydrogen production by the H-type finned tube embedded in the packed bed is considered to be more economical. Based on the thermal flow reversal reactor, the heat transfer characteristics of H-type finned tube embedded on the both sides of high-temperature zone of the packed bed under the quasi-steady were researched. The contribution of radiation heat transfer rate on the H-type finned tube is about 60.5% at most and radiation mainly occurs on the central tube. Within the range of inlet temperature and Re, the fin-assisted degree is both decreased gradually and the maximum is 48.9%. When the temperature is above 906 K or within the range of Re, the heat transfer rate of the fin is mainly from the radiation heat transfer rate. Under the condition of high inlet temperature and high Re, the fin-assisted degree is minimum, which indicates the operation stability of the H-type finned tube is better.

Briefly review the recent structural work of transient receptor potential canonical (TRPC) ion channels by using electron cryo-microscopy (cryo-EM). The high resolution structures of TRPC3, TRPC4, TRPC5 and TRPC6 are discussed.

With the steam obtained by the energy released from ventilation air methane oxidation, the hydrogen production through gasification method is considered more commercial. In order to constrain the steam parameter fluctuation, the shunt honeycomb ceramics are adopted to fill between the heat exchange tubes. However, transient heat transfer characteristics of this kind of heat exchanger have not been fully studied. This paper carried out a numerical simulation study on the transient heat transfer characteristics of H finned tube under periodic reverse-flow conditions. Results show that the existence of shunt honeycomb ceramics enhances the effect of radiation. Gas flow direction reversing destructs the original boundary layer, achieving a sudden rise of the convective heat flux in the new upstream. It takes about 12s to form a new relative stable boundary layer. The apparent heat transfer coefficient achieves a maximum of 108.77 W m−2 K−1 and an average of 99.1 W m−2 K−1.

On a microscopic scale, concrete was regarded as a three-phase composite consisting of coarse aggregate, cement mortar and interface transition zone (ITZ). The coarse aggregates and their peripheral ITZ were equated with equivalent particles blended in cement mortar through two equivalent processes. Taking the effects of ITZ, aggregate gradation, maximum aggregate size and the interactions among equivalent particles into consideration, the average stress of microscopic phase of concrete was calculated based on a micromechanics model, and the stress concentration within ITZ phase was further solved. Adopting the Drucker-Prager criterion to decide the failure of the microscopic phases, the cracking strength, yield strength and ultimate strength of the concrete were calculated respectively when the ITZ cracking, the ITZ failure and the mortar failure occurred. The results were compared with test data to verify the effectiveness and reliability of the model. Based on the model, the influence of the elastic modulus of coarse aggregate, the coarse aggregate content and the elastic modulus of ITZ on the yield strength and ultimate strength are discussed. This paper presents an approach to explore the connection between macroscopic strength and microscopic phase strength, which provides a theoretical reference for studying the failure mechanism of concrete.

Dry-based concrete specimens must be obtained to investigate a moisture effect, but the drying law and strength change vary for concrete of different strength grades under different drying temperatures. In this work, concrete specimens with different strength grades are dried in a thermostatic electric drier at constant temperatures of 60, 80, 105, 120 and 150 °C, and the changes in mass, ultrasonic data and strength of the specimens before and after drying are analysed. The test results demonstrate that the drying stages of concrete with different strength grades at different drying temperatures are generally the same even with variations in drying rate, time and the total water mass loss. Considering the drying temperature and strength grade, a model for concrete drying is obtained based on the modified Page model II. After drying, changes in the concrete compressive and splitting tensile strengths of different strength grade materials are highly similar and are slightly higher than those before drying. The relative strength initially decreases and subsequently increases with increasing drying temperature. The drying temperature 100–125 °C is recommended as the optimal drying temperature for different strength grades of concrete according to the minimal strength change. Further analysis shows that the change in concrete strength is the result of mutual competition between the damage caused by water evaporation and the density increase caused by drying.

Pores, voids correspond to inevitable products in the formation of concrete and significantly affect its macroscopic effective strength. A lot of researches show that both porosity and pore structure have significant influence on the concrete strength and differences exist with respect to those influences on the tensile and compressive strengths. In this paper, first, the relationships between the effective tensile and compressive strengths of concrete and porosity are expressed respectively from the proposed simplified center pore model. Second, in order to further consider the influence of the pore structure, the pore size is chosen as the representative index of pore structure and an influence function related to the pore size is proposed based on the correlation analysis. The total influence coefficient of pore size is obtained by combining the pore size distribution function and influence function. Taking the total influence coefficient into account in the relation between the effective strength and porosity, explicit formulae of porous concrete effective tensile and compressive strengths are finally deduced. Through comparing the present approach with a few classical analytical solutions and experimental observations, the results indicate the reliability and accuracy of the proposed approach and the derived equations are simple and convenient to use. Analysis and discussion suggest that the effect of porosity on the compressive strength of concrete exceeds that of the tensile strength and that the effective concrete strength with the same porosity can be improved by decreasing the pore size.

TRPC4 ion channel was reported to be regulated by small molecular inhibitors and calmodulin. We discuss these findings in the context of other members of TRPC subfamily modulated by different stimulants.

By experimental research on the steel- polyvinyl alcohol (PVA) fibers- calcium carbonate whisker (CW) multi scale fiber-reinforced cement-based composites (MSFRC) after exposure of temperatures up to 900 °C, the flexural, compressive strength, and microstructures of multi scale fibers were investigated in this paper. The incorporation of steel-PVA fibers-CW can effectively improve the flexural and compressive strength of mortar after elevated temperatures. Compared with normal concrete, hybrid fiber reactive powder concrete (RPC) and engineered cement-based composites (ECC), the MSFRC present better capacity of high temperature resistance. The flexural and compressive strength increase first and then decrease with the increasing temperature, and the critical temperatures are 200 °C and 400 °C respectively. Models for describing the relationship between strength, CW content and temperature are proposed. The good high temperature resistance of MSFRC relates to the hybrid effect of melt of PVA fiber, good heat conduction of steel, and the phase transformation from aragonite to calcite of CW. Comprehensive morphology observations by digital camera and optical microscope are simple and useful way to evaluate the changes of fibers and CW at high temperature. This research is very beneficial for the applications of MSFRC in construction project with fire risk.

We and others previously reported that the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6 significantly accumulate with age in mouse lung. This is accompanied by elevated phosphorylation of p38. Here, we further investigate whether aging affects activation of p38 signaling and the inflammatory reaction after exposure to lipopolysaccharide (LPS) in the lungs of mice in vivo and humans ex vivo. The data showed that activation of p38 peaked at 0.5 h and then rapidly declined in young (2-month-old) mouse lung, after intranasal inhalation challenge with LPS. In contract, activation of p38 peaked at 24 h and was sustained longer in aged (20-month-old) mice. As well as altered p38, activations of its upstream activator MKK and downstream substrate NF-κB were also changed in the lungs of aged mice, which corresponded with the absence in the early phase but delayed increases in concentrations of TNF-α, IL-1β and IL-6. Consistent with the above observations in mice, similar patterns of p38 signaling also occurred in human lungs. Compared with younger lungs from adult–middle aged subjects, the activation of p38, MKK and NF-κB, as well as the production of pro-inflammatory cytokines were significantly increased in the lungs of older subjects ex vivo. Exposure of human lung cells to LPS induced rapid activation of p38, MKK and NF-κB in these cells from adult–middle aged subjects, but not older subjects, with increases in the production of the pro-inflammatory cytokines. The LPS-induced rapid activation in the lung cells from adult–middle aged subjects occurred as early as 0.25 h after exposure, and then declined. Compared with adult–middle aged subjects, the LPS exposure did not induce marked changes in the early phase, either in the activation of p38, MKK and NF-κB, or in the production of TNF-α, IL-1β or IL-6 in the lung cells from older subjects. In contrast, these changes occurred relatively late, peaked at 16 h and were sustained longer in the lungs of older subjects. These data support the hypothesis that the sustained activation of the p38 signaling pathway at baseline and the absence in the early phase but delayed of p38 signaling pathway response to LPS in the elderly may play important roles in increased susceptibility of aged lungs to inflammatory injury.

RIG-I activates interferon signaling pathways by promoting filament formation of the adaptor molecule, MAVS. Assembly of the MAVS filament is mediated by its CARD domain (CARD(MAVS)), and requires its interaction with the tandem CARDs of RIG-I (2CARD(RIG-I)). However, the precise nature of the interaction between 2CARD(RIG-I) and CARD(MAVS), and how this interaction leads to CARD(MAVS) filament assembly, has been unclear. Here we report a 3.6 Å electron microscopy structure of the CARD(MAVS) filament and a 3.4 Å crystal structure of the 2CARD(RIG-I):CARD(MAVS) complex, representing 2CARD(RIG-I) "caught in the act" of nucleating the CARD(MAVS) filament. These structures, together with functional analyses, show that 2CARD(RIG-I) acts as a template for the CARD(MAVS) filament assembly, by forming a helical tetrameric structure and recruiting CARD(MAVS) along its helical trajectory. Our work thus reveals that signal activation by RIG-I occurs by imprinting its helical assembly architecture on MAVS, a previously uncharacterized mechanism of signal transmission.

An increasing body of evidence suggests that soluble assemblies of amyloid beta-protein (Abeta) play an important role in the initiation of Alzheimer disease (AD). In vitro studies have found that synthetic Abeta can form soluble aggregates through self-assembly, but this process requires Abeta concentrations 100- to 1000-fold greater than physiological levels. Tissue transglutaminase (TGase) has been implicated in neurodegeneration and can cross-link Abeta. Here we show that TGase induces rapid aggregation of Abeta within 0.5-30 min, which was not observed with chemical cross-linkers. Both Abeta40 and Abeta42 are good substrates for TGase but show different aggregation patterns. Guinea pig and human TGase induced similar Abeta aggregation patterns, and oligomerization was observed with Abeta40 concentrations as low as 50 nm. The formed Abeta40 species range from 5 to 6 nm spheres to curvilinear structures of the same width, but up to 100 nm in length, that resemble the previously described self-assembled Abeta protofibrils. TGase-induced Abeta40 assemblies are resistant to a 1-h incubation with either neprilysin or insulin degrading enzyme, whereas the monomer is rapidly degraded by both proteases. In support of these species being pathological, TGase-induced Abeta40 assemblies (100 nm) inhibited long term potentiation recorded in the CA1 region of mouse hippocampus slices. Our data suggest that TGase can contribute to AD by initiating Abeta oligomerization and aggregation at physiological levels, by reducing the clearance of Abeta due to the generation of protease-resistant Abeta species, and by forming Abeta assemblies that inhibit processes involved in memory and learning. Our data suggest that TGase might constitute a specific therapeutic target for slowing or blocking the progression of AD.

A procedure for the sequential determination of arsenite [As(III)] and arsenate [As(V)] based on electrochemical detection for As(III) and spectrophotometric detection for As(V) following ion chromatographic separation was developed. The color-developing system was based on the ion-association complex formed by heteropolymolybdoarsenic acid with bismuth in the presence of Triton X-100. Experimental conditions for electrochemical detection and color-developing conditions were optimized for As(III) and As(V), respectively. The optimal applied potential for electrochemical detection of As(III) was + 0.35 V and the wavelength for spectrophotometric detection of As(V) was 700 nm. By using an eluent of 2.0 mM sodium hydrogencarbonate-5.5 mM sodium carbonate with a 175 μl sample loop for ion chromatographic separation, the detection limits, which are defined as the concentrations that give the peak intensity twice the baseline noise, are found to be 2.9 μg/l for As(III) and 13 μg/l for As(V), respectively. The spiked waste water samples were analyzed and recoveries were found to be 97.5–104% for As(III) and 93.5–103% for As(V), respectively.