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Lime treatment combined with vacuum preloading has been used in the treatment of dredging slurry for many years. Previous studies have indicated that particle grading, which is one of the essential properties of slurry, could affect the pore-size distribution and compression characteristics of slurry and thus affect the efficacy of the lime treatment and vacuum preloading. However, the effect of particle grading has not yet been examined quantitatively. This study investigated the compressibility of lime-treated slurries with different particle gradings using a one-dimensional oedometer for compression testing. A series of laboratory model tests were carried out to examine the effect of particle grading on the efficacy of lime-treated slurry with vacuum preloading. The results showed that particle grading significantly influences optimal lime content. For clay or low-plasticity silt, the optimum lime content for lime treatment combined with vacuum preloading was found to be 2%. When slurry contains increased silt and sand grains, more lime is required to achieve effective lime treatment. However, excessive lime would reduce the efficacy of lime treatment on the compressibility and permeability of the soil. [ABSTRACT FROM AUTHOR]

For a vulcanized elastomer compound containing no filler, variation of dynamic moduli with swain was examined in the transition zone approaching glass transition at 0.1, 1, 10, and 15 Hz. In the complete absence of filler-filler/filler-polymer interactions, the nonlinearity in dynamic moduli becomes enhanced upon approaching glass transition regardless of testing frequency. Under the test protocol employed, the extraordinary nonlinearity at 10 Hz and 15 Hz is shown to be associated with a spectacular shear-heating event. At 10 Hz and -19°C, a pronounced yielding-like peak in the in-phase stress component emerges at small strain (< 2%) during testing of increasing strain. However, the corresponding temperature rise here is only about 0.4°C. Interestingly, at or above 0°C, no such peak in the in-phase stress component emerges for compounds filled with reinforcing filler above the percolation threshold. Discussion is also made relating the observations to the sliding friction of rubber materials., INTRODUCTION Dynamic performance characteristics of pneumatic tires such as sliding friction related to driving safety and rolling resistance related to vehicle fuel consumption depend critically on the nonlinear dynamic viscoelastic [...]

In many existing elastoplastic plane-strain solutions for a circular tunnel excavated in a homogeneous, isotrophic rock mass under a hydrostatic stress field, the longitudinal axial stress (or the out-of-plane stress) [[Sigma].sub.z] is not correctly evaluated. This paper describes the concepts and a numerical method to calculate this stress component and proposes analytical solutions for practical applications. The computed numerical solutions are compared with theoretical solutions where possible. The relations between rock-mass dilatancy, tunnel displacements, and the in-situ stress field are investigated. Mohr-Coulomb and Hoek-Brown yield criteria with appropriate plastic potential functions and nonassociated flow rules are used in the brittle plastic calculations. The effects of various boundary conditions on the numerical analyses are discussed and several important practical conclusions are drawn from the investigations.

Abstract Background Reactive microglia are associated with β-amyloid (Aβ) deposit and clearance in Alzhiemer's Disease (AD). Paradoxically, entocranial resident microglia fail to trigger an effective phagocytic response to clear Aβ deposits although they mainly exist in an "activated" state. Oligomeric Aβ (oAβ), a recent target in the pathogenesis of AD, can induce more potent neurotoxicity when compared with fibrillar Aβ (fAβ). However, the role of the different Aβ forms in microglial phagocytosis, induction of inflammation and oxidation, and subsequent regulation of phagocytic receptor system, remain unclear. Results We demonstrated that Aβ(1-42) fibrils, not Aβ(1-42) oligomers, increased the microglial phagocytosis. Intriguingly, the pretreatment of microglia with oAβ(1-42) not only attenuated fAβ(1-42)-triggered classical phagocytic response to fluorescent microspheres but also significantly inhibited phagocytosis of fluorescent labeled fAβ(1-42). Compared with the fAβ(1-42) treatment, the oAβ(1-42) treatment resulted in a rapid and transient increase in interleukin 1β (IL-1β) level and produced higher levels of tumor necrosis factor-α (TNF-α), nitric oxide (NO), prostaglandin E2 (PGE2) and intracellular superoxide anion (SOA). The further results demonstrated that microglial phagocytosis was negatively correlated with inflammatory mediators in this process and that the capacity of phagocytosis in fAβ(1-42)-induced microglia was decreased by IL-1β, lippolysaccharide (LPS) and tert-butyl hydroperoxide (t-BHP). The decreased phagocytosis could be relieved by pyrrolidone dithiocarbamate (PDTC), a nuclear factor-κB (NF-κB) inhibitor, and N-acetyl-L-cysteine (NAC), a free radical scavenger. These results suggest that the oAβ-impaired phagocytosis is mediated through inflammation and oxidative stress-mediated mechanism in microglial cells. Furthermore, oAβ(1-42) stimulation reduced the mRNA expression of CD36, integrin β1 (Itgb1), and Ig receptor FcγRIII, and significantly increased that of formyl peptide receptor 2 (FPR2) and scavenger receptor class B1 (SRB1), compared with the basal level. Interestingly, the pre-stimulation with oAβ(1-42) or the inflammatory and oxidative milieu (IL-1β, LPS or t-BHP) significantly downregulated the fAβ(1-42)-induced mRNA over-expression of CD36, CD47 and Itgb1 receptors in microglial cells. Conclusion These results imply that Aβ oligomers induce a potent inflammatory response and subsequently disturb microglial phagocytosis and clearance of Aβ fibrils, thereby contributing to an initial neurodegenerative characteristic of AD. Antiinflammatory and antioxidative therapies may indeed prove beneficial to delay the progression of AD.

The newly discovered Dongyang low‐sulphidation epithermal Au deposit is located in central‐eastern Fujian Province, coastal SE China. Ore bodies occur in Late Jurassic rhyolite porphyry, rhyolite, and dacitic crystal tuff lava. In this study, rhyolite and dacitic crystal tuff lava are dated to 151.9 ± 0.4 Ma and 158.3 ± 0.4 Ma, respectively, and belong to the second member of the Nanyuan Formation. They are high in K2O (6.91–3.81 wt%) and Na2O/K2O (0.55–0.02), strongly peraluminous (A/CNK = 2.11–1.67) and high‐K calc‐alkaline or shoshonitic. They contain low ∑REEs (248–125 ppm), are enriched in Rb, K, Au, and depleted in Ba, Sr, P, Zr, Hf, and have slightly negative Eu anomalies (δEu = 0.94–0.56), suggesting that they are weakly fractionated felsic volcanic rocks. The zircon εHf(t) values (−11.2 to −5.4; two‐stage model ages = 2,650–2,128 Ma) suggest that they were mainly derived from Palaeoproterozoic crust. Lead isotope compositions also imply a dominantly lower crustal source. Detailed geological characteristics and elemental and isotopic data suggest that the oxidizing and weakly fractionated nature of the Dongyang high‐K felsic magma may have played a key role in Au mineralization. Integrating new and published data on the tectonic evolution, we suggest that the Late Jurassic Au mineralization and its causative magmatism actually extended to the SE China coastal area. The Dongyang rhyolite and dacitic crystal tuff lava may have been generated from partial melting of the crust caused by underplating of mantle‐derived magmas in an extensional environment. Regional extension may have been related to the NW‐directed roll‐back of the Palaeo‐Pacific Plate beneath the South China Block. [ABSTRACT FROM AUTHOR]

Vitamin D is the name given to a series of compounds with antirachitic activity. In this study, we developed a method for quantification of the common Vitamin D, ergocalciferol (vitamin D2), and cholecalciferol (vitamin D3), in edible fungus by reversed-phase two-dimensional liquid chromatography. The sample was saponified by KOH ethanol solution and extracted with ethyl acetate and n-hexane. After reconcentration, the sample was directly injected for instrumental analysis. The results showed that the spiking recoveries of vitamin D2 and vitamin D3 were 80.4–93.8% and 82.3–92.0%, respectively. The relative standard deviations (RSDs) were all less than 5%. Comparing to the results of isotope dilution liquid chromatography tandem mass spectrometry, there were no significant differences (P > 0.05). The method was applied for testing vitamin D2 and D3 in 9 kinds of edible mushrooms. It showed that vitamin D3 was not detected. The content of vitamin D2 ranged from 0.11 μg/100 g to 123 μg/100 g. The content of vitamin D2 in dried mushroom was the highest, while that in fresh mushroom was the lowest. The limit of quantification was 0.025 μg/100 g. [ABSTRACT FROM AUTHOR]