299 research outputs found

    The Role of Waste Glass Powder During the Hydration Process of Composite Cementitious Materials

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    The role of waste glass powder (GP) during the hydration process of composite cementitious materials was investigated by using mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The compressive strength was also tested. The results indicate that the chemical activity of GP is low. But the pozzolanic reactivity of GP greatly improves with its fineness and the elevated curing temperature, which contributes to improving the mechanical strength. The hydration process of composite cementitious material containing GP is similar to that of pure cement. With the increase of GP content in the composite cement, the occurring time of second exothermic improves, but the value of second exothermic peak and the cumulative hydration heat reduce. The characteristic pore size of pastes containing GP decreases over curing age, which significantly improves their strength. GP does not modify the type of hydration products of composite cementitious material. The microstructure of hardened pastes containing GP is dense due to the generation of C-S-H gel with a low Ca/Si ratio. There is a reaction ring along GP with high fineness, which can enhance the interfacial transition zone to avoid ASR

    Biological Subtle Motion Magnification Based on 3D Wavelet Transform

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    This paper presents an amplification algorithm of subtle motion which reveals important aspects of the world. Our analysis is based on spatial and temporal projection of decomposition of the viewpoint video by using 3D wavelet transform, which is used to estimate the optimal scale and threshold function in order to extract the interested region. We discuss parameters of effect and estimate the threshold function by employing integral energy and maximum values of pixels. The results of the subtle motion magnification by using the optimal scale and threshold function have a good effec

    The Role of Various Powders during the Hydration Process of Cement-Based Materials

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    The role of various powders including glass powder (GP), limestone powder (LP), and steel slag powder (SSP) during the hydration process of cement-based materials was investigated by using X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), and strength tests. GP has adverse impact on early strength, but the pozzolanic reaction at later stage enhances the strength development greatly. LP can significantly improve early strength. SSP has a good contribution to the early and later strength of the paste when its content is less than 15%. GP has little effect on the kind of hydration products but relatively large effects on the quantity. Calcium hydroxide (CH) content of GP paste decreases over curing age gradually, which is different from pure cement paste because its pozzolanic activity consumes more CH than that generated from the cement hydration. SSP and LP mainly play a role of filling effect at early stage. Nucleating effect of LP also promotes the early hydration of cement. The hydration of LP occurs at later stage and forms the calcium carboaluminate hydrates. The hydration of SSP is relatively slow, which generates CH at later stage and is effective in the strength development

    Causes Analysis and Preventive Measures of Blood Donation Reaction of University Student

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    Objective: To analyze the causes of blood donation reaction of university students, propose appropriate preventive measures to avoid blood waste and ensure the quality of the blood. Methods: The university students in Guiyang city were selected from January to December 2010, The cases of blood donation reaction and the causes are analyzed on 7063 college students. Results: Among the 7063 college students, there are 292 students with blood donation reaction, the main cause is psychological factors, followed by fatigue before blood donation, not-ideal blood donation environment, limosis or starvation, etc. It occurs more in the first time donors. blood donors with different times and posture have different adverse reactions. Conclusion: Constantly summarizing experiences, development and implementation of scientific and causable preventive measures, improving the environment for blood donation, strengthening the sense of responsibility and sense of service of blood collection personnel, strengthening psychological nursing, giving donors a warm caring and confidence as far as possible, making donors relax mind and in the best state can help to reduce and prevent the occurrence of blood donation reaction, organize  more donators and college students to actively participate in blood donation, in order to promote vigorous, healthy and sustained development of voluntary blood donation. The blood donation adverse reactions of university students are related to the frequency of blood donation and posture, we have developed a series of preventive measures against the causes of blood donation adverse reactions to reduce the incidence of adverse reactions

    Circ-RNF13, as an oncogene, regulates malignant progression of HBV-associated hepatocellular carcinoma cells and HBV infection through ceRNA pathway of circ-RNF13/miR-424-5p/TGIF2

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    Circular RNA RNF13 (circ-RNF13; ID: hsa_circ_0067717) is newly identified to be abnormally upregulated in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) patients. However, its role and mechanism remain to be further annotated. First of all, real-time quantitative PCR (RT-qPCR) was utilized to examine RNA expression, and circ-RNF13 was upregulated in HBV-infected human HCC tissues and HBV-expressing cells (Huh7-HBV and Hep3B-HBV), accompanied with TGFβ-induced factor homeobox 2 (TGIF2) upregulation and microRNA (miR)-424-5p downregulation. Loss-of-functional experiments were performed using MTS assay, colony formation assay, flow cytometry, enzyme-linked immunosorbent assay, transwell assay, and xenograft tumor model. As a result, blocking circ-RNF13 enhanced the apoptosis rate of Huh7-HBV and Hep3B-HBV cells, but inhibited cell proliferation, colony formation, migration, and invasion in vitro, along with suppressed tumor growth in vivo. Besides, RT-qPCR data showed that HBV DNA copies and levels of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) were diminished by circ-RNF13 knockdown in Huh7-HBV and Hep3B-HBV cells. Mechanistically, circ-RNF13 and TGIF2 could directly interacting with miR-424-5p according to dual-luciferase reporter assay, suggesting that circ-RNF13 and TGIF2 served as competing endogenous RNAs (ceRNAs) for miR-424-5p. Functionally, overexpressing miR-424-5p mimicked and silencing miR-424-5p counteracted the effects of circ-RNF13 depletion in HBV-expressing HCC cells in vitro; TGIF2 restoration partially abrogated the role of miR-424-5p upregulation. In conclusion, circ-RNF13 might sponge miR-424-5p to suppress HBV-associated HCC cells malignant progression and HBV infection by regulating TGIF2, providing a novel insight into the occurrence and treatment of HBV-associated HCC.

    Discovery and excavation of lichen bioactive natural products

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    Lichen natural products are a tremendous source of new bioactive chemical entities for drug discovery. The ability to survive in harsh conditions can be directly correlated with the production of some unique lichen metabolites. Despite the potential applications, these unique metabolites have been underutilized by pharmaceutical and agrochemical industries due to their slow growth, low biomass availability, and technical challenges involved in their artificial cultivation. At the same time, DNA sequence data have revealed that the number of encoded biosynthetic gene clusters in a lichen is much higher than in natural products, and the majority of them are silent or poorly expressed. To meet these challenges, the one strain many compounds (OSMAC) strategy, as a comprehensive and powerful tool, has been developed to stimulate the activation of silent or cryptic biosynthetic gene clusters and exploit interesting lichen compounds for industrial applications. Furthermore, the development of molecular network techniques, modern bioinformatics, and genetic tools is opening up a new opportunity for the mining, modification, and production of lichen metabolites, rather than merely using traditional separation and purification techniques to obtain small amounts of chemical compounds. Heterologous expressed lichen-derived biosynthetic gene clusters in a cultivatable host offer a promising means for a sustainable supply of specialized metabolites. In this review, we summarized the known lichen bioactive metabolites and highlighted the application of OSMAC, molecular network, and genome mining-based strategies in lichen-forming fungi for the discovery of new cryptic lichen compounds

    Magnetic States of the Two-Leg Ladder Alkali Metal Iron Selenides AAFe2_2Se3_3

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    Recent neutron scattering experiments addressing the magnetic state of the two-leg ladder selenide compound BaFe2_2Se3_3 have unveiled a dominant spin arrangement involving ferromagnetically ordered 2×\times2 iron-superblocks, that are antiferromagnetically coupled among them (the "block-AFM" state). Using the electronic five-orbital Hubbard model, first principles techniques to calculate the electronic hopping amplitudes between irons, and the real-space Hartree-Fock approximation to handle the many-body effects, here it is shown that the exotic block-AFM state is indeed stable at realistic electronic densities close to n6.0n \sim 6.0. Another state (the "CX" state) with parallel spins along the rungs and antiparallel along the legs of the ladders is close in energy. This state becomes stable in other portions of the phase diagrams, such as with hole doping, as also found experimentally via neutron scattering applied to KFe2_2Se3_3. In addition, the present study unveils other competing magnetic phases that could be experimentally stabilized varying either nn chemically or the electronic bandwidth by pressure. Similar results were obtained using two-orbital models, studied here via Lanczos and DMRG techniques. A comparison of the results obtained with the realistic selenides hoppings amplitudes for BaFe2_2Se3_3 against those found using the hopping amplitudes for pnictides reveals several qualitative similarities, particularly at intermediate and large Hubbard couplings.Comment: 10 pages, 6 figure

    Microbial proteases and their applications

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    Proteases (proteinases or peptidases) are a class of hydrolases that cleave peptide chains in proteins. Endopeptidases are a type of protease that hydrolyze the internal peptide bonds of proteins, forming shorter peptides; exopeptidases hydrolyze the terminal peptide bonds from the C-terminal or N-terminal, forming free amino acids. Microbial proteases are a popular instrument in many industrial applications. In this review, the classification, detection, identification, and sources of microbial proteases are systematically introduced, as well as their applications in food, detergents, waste treatment, and biotechnology processes in the industry fields. In addition, recent studies on techniques used to express heterologous microbial proteases are summarized to describe the process of studying proteases. Finally, future developmental trends for microbial proteases are discussed
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