Structure characterization, physicochemical property and immunomodulatory activity on RAW264.7 cells of a novel triple-helix polysaccharide from Craterellus cornucopioides

In the study, a new triple-helix polysaccharide with favorable stability was purified from C. cornucopioides. Its structural characterization, stability and solution behavior were investigated by the GC-MS, periodate oxidation-smith degradation, FT-IR, 1D and 2D NMR spectroscopy, methylation analysis, Scanning electron microscope, Congo-red, CD, TGA and DSC analysis. The results showed that Craterellus cornucopioide polysaccharide (CCP) possessed the molecular weight of 1.97 × 10³ kDa, is mainly composed of mannose (48.73%), galactose (17.37%), glucose (15.97%) and xylose (17.93%), respectively. It was a heteroglycan with (1 → 3)‑linked‑β‑d‑Manp‑(1 → 6)‑linked α‑d‑Galp backbone distributed by (1 → 4)‑linked‑α‑d‑Xylp‑t‑α‑d‑Manp and t‑β‑d‑Glup units at O-6. The result of TGA and DSC assay indicated that CCP has a favorable thermal stability. MTT and Scanning electro microscopy (SEM) assay showed that CCP could significantly improve the proliferation activity and induce cells activation of RAW264.7 in a certain range of concentrations and period.

Microscopic dynamics of structural transition in iron with a nanovoid under shock loading

The shock-induced bcc (body-centered cubic) to hcp (hexagonal-closed packing) transition in iron containing a nanovoid was investigated by molecular dynamics simulations with a shock-front absorbing boundary condition. The results demonstrate the transition time induced by a nanovoid reduces exponentially with increasing shock pressure, which indicates a similar law to the recent experimental observations. Micromorphology evolution of hcp nuclei is presented by the atomic centrosymmetry parameter. A flaky growth pattern along the {111} planes is observed, while the system finally forms into a laminar structure along the {110} planes. Furthermore, the atomic mechanical path through the transition is analyzed in detail. It is found that the transformed atoms do cross a shear pressure barrier and then show an over-relaxation of pressure, while their potential increases to a much higher value than bcc atoms.

Dynamic properties of structural transition in iron under uniaxial compression

By using molecular dynamics simulations, we have successfully simulated the bcc [Formula: see text] hcp structural transition in single-crystal iron under isothermal compression along the [001] direction. The results reveal a distinct softening of C(33) and a hardening of C(31) (or C(32)) prior to the transition and an over-relaxation of the stress after transition. Above the critical stress the morphology evolution of structural transition is analyzed, which can be divided into four stages: hcp homogeneously nucleated, columnar grains formed, nuclei competed and merged, and a laminar structure formed along {110} planes. Besides, our simulations demonstrate that in mixed phases the hcp phase has negative shear stress and the potential of the hcp phase is higher than the bcc phase, and the shear stress of the system keeps a linear decrease with hcp mass fraction. The effect of temperature on the structural transition is also discussed.

A double-blind trial of oral immunotherapy for Artemisia pollen asthma with evaluation of bronchial response to the pollen allergen and serum-specific IgE antibody

Eighteen asymptomatic Artemisia pollen asthma patients with normal pulmonary function were selected for a double-blind trial of oral immunotherapy. Each patient had a positive skin test to Artemisia pollen extract and also a positive bronchial challenge response to the same extract. The patients were randomly assigned to active treatment or placebo group and received intensive oral administration of Artemisia pollen extract over a 50-day course. The nine patients who received the active treatment ingested a cumulative dose of 396,652 PNU and showed a significant decrease in serum-specific IgE antibodies (P less than .05) and a significant reduction in bronchial sensitivity to the same extract (P less than .01). The changes in these two variables correlated well (r = .8787, P less than .01). The nine patients who received the placebo showed no significant changes in serum-specific IgE or bronchial sensitivity to Artemisia pollen extract. Follow-up of two cases with the same extract showed that the reductions in serum-specific IgE as well as bronchial sensitivity induced by oral immunotherapy were maintained for 3 months.