Two new sesquiterpenoids with glycosides from the leaves and stems of Schisandra chinensis (Turcz.) Baill.

Two previously undescribed glycosidic bisnorsesquiterpenoids A - B (1 - 2), together with two known compounds (3 - 4), were isolated from the leaves and stems of Schisandra chinensis. Their structures were elucidated by extensive spectroscopic data (1D, 2D NMR, and HRESIMS). The anti-inflammatory activity, ABTS+ radical scavenging activity, and DPPH radical scavenging activity of compounds 1 - 4 were tested. However, all of these compounds showed only weak anti-inflammatory or antioxidant effects.

[A new norsesquiterpenoid from Schisandra chinensis].

This study investigated the chemical components from the leaves and stems of Schisandra chinensis. Three norsesquiterpenoids were isolated from S. chinensis by various column chromatographies(silica gel, Sephadex LH-20, and MCI), reversed-phase medium-pressure preparative, and semi-preparative high-performance liquid chromatography(HPLC). Their structures were identified based on physicochemical properties, mass spectrometry(MS), nuclear magnetic resonance(NMR), ultraviolet(UV), and electro-nic circular dichroism(ECD) as(3R,4R,5R,6S,7E)-3,4,5,6-tetrahydroxy-7-megastigmen-9-one(1),(3S,5R,6R,7E)-3,5,6-trihydroxy-7-megastigmen-9-one(2), and(3S,4R,9R)-3,4,9-trihydroxymegastigman-5-ene(3). Compound 1 was a new compound, and its absolute configuration was determined by ECD. Compounds 2 and 3 were isolated from the Schisandra plant for the first time.

Four sesquiterpenoids from the vegetable raw material Schisandra chinensis (Turcz.) Baill.: leaves and stems.

Four sesquiterpenoids A-D (1-4) were isolated from the ethanol extracts of the leaves and stems from Schisandra chinensis. Their structures and absolute configurations were elucidated by a combination of NMR, MS and ECD. Compounds 1-4 (10 µM) exhibited moderate hepatoprotective activities against APAP-induced LO2 cell damage with increasing cell viability by 18%, 17%, 16%, and 19% compared to the model group (bicyclol, 26%) at 10 µM, respectively. All the compounds displayed no cytotoxic activity against five human cell lines, which also suggested the safety of leaves and stems of S. chinensis as an edible vegetable in a degree.

Molecular force transfer mechanisms in graphene oxide paper evaluated using atomic force microscopy and in situ synchrotron micro FT-IR spectroscopy.

The mechanical properties of graphene oxide (GO) paper are critically defined both by the mechanical properties of the constituent GO sheets and the interaction between these sheets. Functional carbonyl and carboxyl groups decorating defects, expected to be predominantly sheet edges of the GO, are shown to transfer forces to the in-plane carbon-carbon bonding using a novel technique combining atomic force microscopy (AFM) to mechanically deform discrete volumes of GO materials while synchrotron Fourier-transform infra-red (FTIR) microspectroscopy evaluated molecular level bond deformation mechanisms of the GO. Spectroscopic absorption peaks corresponding to in-plane aromatic C=C bonds from GO sheets were observed to shift during tensile tests. Importantly, FTIR provided information on clear absorption peak shifts from C=O bonds linking along the GO sheet edges, indicating transfer of forces between both C=C and C=O bonds during tensile deformation. Grüneisen parameters were used to quantitatively link the macroscopic FTIR peak shifts to molecular level chemical bond strains, with relatively low bond strains prevalent when applying external forces to the GO paper suggesting probing of hydrogen bonding interactions. We propose a mechanistic description of molecular interactions between GO sheets in the paper from these experiments, which is important in future strategies for further modification and improvement of GO-based materials.

Influence of carbon nanotubes microstructures inside composites on the loading role of nanotubes bore.

To fully utilize the extraordinary mechanical properties of carbon nanotubes (CNTs) in composites, great attention has been paid to prepare CNTs based composites with uniformly dispersion and strong interfacial adhesion. With the help of micro-Raman spectroscopy, herein, we study the influence of nanotube microstructures (e.g., dispersion and orientation) on the loading role of nanotubes bore. By using the same batch of composite solutions, two types of composite materials with different nanotube morphologies were prepared by electrospun and solution casting methods. Raman results have revealed that the loading-role of nanotubes bore in the electrospun nonwoven mats is much stronger than that of regular composite films owing to its uniformly dispersion as well as high orientation.

The effect of interlayer adhesion on the mechanical behaviors of macroscopic graphene oxide papers.

High mechanical performances of macroscopic graphene oxide (GO) papers are attracting great interest owing to their merits of lightweight and multiple functionalities. However, the loading role of individual nanosheets and its effect on the mechanical properties of the macroscopic GO papers are not yet well understood. Herein, we effectively tailored the interlayer adhesions of the GO papers by introducing small molecules, that is, glutaraldehyde (GA) and water molecules, into the gallery regions. With the help of in situ Raman spectroscopy, we compared the varied load-reinforcing roles of nanosheets, and further predicted the Young's moduli of the GO papers. Systematic mechanical tests have proven that the enhancement of the tensile modulus and strength of the GA-treated GO paper arose from the improved load-bearing capability of the nanosheets. On the basis of Raman and macroscopic mechanical tests, the influences of interlayer adhesions on the fracture mechanisms of the strained GO papers were inferred.

Fabrication of high optical transparent and conductive SWNT based transparent conducting film on flexible plastic substrate using ozone as a redox dopant.

In the present work, single-wall carbon nanotubes-transparent conducting films (SWNTs-TCFs) were fabricated at room temperature on a flexible polycarbonate substrate using the ultrosonication-dip-coating technique. Ozone was employed to reduce the sheet resistance of conductive film. As a result, the sheet resistance of film was decreased drastically after 1.5 hr ozone (O3) treatment and could reach up to 170 omega/square at 80% T at 550 nm wavelength. In addition, aminopropyltriethoxysilane (APTS) was further applied as an adhesion promoter in order to enhance the adhesion between the SWNTs films and the substrate. Experimental results show that ATPS can greatly improve the adhesion of SWNTs coating to the substrate without the loss of conductivity.