The search for a maximum of the D-π-A paradigm for second order nonlinear optical molecular materials.

Push-pull π-conjugated molecules are one of the paradigms of second order nonlinear optical (NLO) materials and have been extensively explored. However, high-performance second order NLO materials with an optimum electron donor (D), π-bridge (π) and acceptor (A) under this paradigm are still the most sought-after. In the present work, D-π-A molecules with optimal D, π and A combination for strong second order NLO properties are proposed based on molecular orbital theories. The optimal D-π-A push-pull molecule achieves an unprecedentedly strong NLO response under the D-π-A paradigm, i.e., the static first hyperpolarizability reaches -453.92 × 10-30 esu per heavy atom using azulene as part of the π-bridge and acceptor to synergistically reinforce the strength of the acceptor. The protocols of D-π-A NLO molecule design through frontier molecular orbital matching of D, π and A with optimal combination of electron donating and accepting strengths shed light on future molecular NLO materials exploration. The simulated two-dimensional second order spectra provide useful information (e.g., sum frequency generation) on the applications of those D-π-A push-pull molecules in nonlinear optics.

Butterfly-Shaped Nanographenes with Excellent Second-Order Nonlinear Optical Properties: The Synergy of B/N and Azulene.

Azulene, a simple polar polycyclic aromatic hydrocarbon with connected electron donor and acceptor (DA), ignites the hope of designing second-order nonlinear optical (NLO) molecular materials from pure nonpolar carbon nanomaterials. In this work, a butterfly-shaped nanographene (π-DA-π) was designed by incorporating azulene between two coronenes. One more electron in a N atom or one electron fewer in a B atom with respect to a C atom can polarize charge distribution in carbon nanomaterials, and further doping of B and N in the designed butterfly-shaped nanographene changes the system from π-DA-π to D-π-A, leading to strong NLO responses. For example, the largest static first hyperpolarizability even reaches 173.89×10-30  esu per heavy atom. The synergetic role of B, N and azulene in the nanographene is scrutinized, and such a doping strategy is found to provide an effective means for the design of carbon-based functional materials. The strong second-order NLO responses of these butterfly-shaped carbon-based nanographenes under external fields, for example, sum frequency generation and difference frequency generation, could inspire future experimental exploration.

Spin engineering of triangulenes and application for nano nonlinear optical materials design.

The recently synthesized triangulenes with non-bonding edge states could have broad potential applications in magnetics, spintronics and electro-optics if they have appropriate electronic structure modulation. In the present work, strategies based on molecular orbital theory through heteroatom doping are proposed to redistribute, reduce or eliminate the spin of triangulenes for novel functional materials design, and the role of B, N, NBN, and BNB in such intended electronic structure manipulation is scrutinized. π-Extended triangulenes with tunable electronic properties could be potential nonlinear optical (NLO) materials with appropriate inhibition of their polyradical nature. The elimination of spin is achieved by B, N, NBN, and BNB doping with the intended geometric arrangement for enhanced polarity. Intended doping of BNB results in an optimal structure with large static first hyperpolarizability (〈ß0〉) as well as strong Hyper-Rayleigh scattering (HRS) ßHRS(-2ω; ω, ω) (ω = 1064.0 nm), TG7-BNB-ba with a large 〈ß0〉 (18.85 × 10-30 esu per heavy atom) and ßHRS (1.15 × 10-28 esu per heavy atom) much larger than that of a synthesized triangular molecule (1.12 × 10-30 esu of 〈ß0〉 per heavy atom and 5.04 × 10-30 esu of ßHRS per heavy atom). The strong second order NLO responses in the near-infrared and visible regions, particularly the strong sum frequency generation, make these B or (and) N doped triangulenes promising candidates for the fabrication of novel carbon-based optoelectronic devices and micro-NLO devices.

Strong second order nonlinear optical properties of azulene-based porphyrin derivatives.

The high stability, feasible modification, and good π-conjugation of porphyrin derivatives render these porphyrin-based nanomaterials suitable as potential third order nonlinear optical (NLO) materials. Introducing an azulene in pristine porphyrins can significantly improve the second order NLO properties of the system, and this is studied in the present work using density functional theory based methods and the sum-over-states model. The relative orientation of azulene plays a determinant role in the enhancement of the static first hyperpolarizability (〈ß0〉), e.g., the 〈ß0〉 per heavy atom increases from 0.31 × 10-30 esu to 9.78 × 10-30 esu. Further addition of metals (Mg and Zn) in these azulene-fused porphyrin systems leads to an even larger 〈ß0〉 per heavy atom of 41.59 × 10-30 esu, much larger than that of a recently reported porphyrin derivative (26.47 × 10-30 esu). A novel strategy to stabilize the electronic structures as well as maintain good second order NLO responses by introducing appropriate metals into the azulene-fused porphyrins is extendable to other similar systems. Strong sum frequency generation and different frequency generations of those azulene-fused porphyrins in visible and near-infrared regions may inspire experimental exploration and related applications of azulene-based porphyrins particularly in biological nonlinear optics.

Tuning the edge states in X-type carbon based molecules for applications in nonlinear optics.

Novel carbon based "X-type" graphene nanoribbons (GNRs) with azulenes were designed for applications in nonlinear optics in the present work, and the second order nonlinear optical (NLO) properties of those X-type GNRs were predicted using the sum-over-states (SOS) model. The GNRs with edge states are feasibly polarized. The effects of zigzag edges on the NLO properties of GNRs are scrutinized by passivation, and the electronic structures of GNRs are modulated with heteroatoms at the zigzag edges for improved stability and NLO properties. Those nanomaterials were further functionalized with electron-donating and electron-withdrawing groups (NH2/NO2) to enhance the NLO responses, and the connection of those functional groups at the azulene ends play a determinant role in the enhancement of the NLO properties of those X-type nanoribbons, e.g., the static first hyperpolarizability (〈ß0〉) changes from -783.23 × 10-30 esu to -1421.98 × 10-30 esu. The mechanism of such an enhancement has been investigated. Through two-dimensional second order NLO spectra simulations, particularly besides the strong electro-optical Pockels effect and optical rectification responses, strong electronic sum frequency generations and difference frequency generations are observed in those GNRs. The strong second order NLO responses of those GNRs in the visible light region bring about potential applications of these carbon nanomaterials in nonlinear nanophotonic devices and biological nonlinear optics.

Simulation based study of magnetic velocity induction system by using Analysis System Electromagnetics Suite.

The magnetic velocity induction system (MAVIS) is commonly used for velocimetry in shock compression experiment. Due to some discrepancies, the variation in induced voltage amplitude is ambiguous, which makes the simulation of this experiment particularly significant. In this work, we have designed a MAVIS, which was used to determine the induced voltage amplitude and flyer velocity. We built a three-dimensional model of MAVIS and performed the simulations using the Analysis System Electromagnetics Suite. Additionally, we performed some experiments and compared the results of both studies on the basis of flyer thickness, radius, and velocity. It was established that the flyer velocity influenced the induced electromotive force (EMF) in the pick-up coils. The increase in flyer radius led to the increase in the induced EMF. The cut-off radius for flyers was also discussed in detail by computing the lowest induced EMFs at discrete flyer velocities and radii. Due to the eddy current loss, experimental data laid slightly lower than simulations. The simulation data have proved its accuracy within the experimental error range. Thus, it can be applied as an economical framework to calculate projectile velocity precisely, regardless of its geometry, and to estimate the trigger level of the oscilloscope before performing the experiments. In order to enhance the quality of induced voltage, we also proposed a new design consisting of three pick-up coils. This redesigned MAVIS contributed significantly in signal narrowing as well as controlled the loss in amplitude peaks that reduced the experimental uncertainty in flyer velocity <0.4%.

Elevated CO2 Concentration Alters Photosynthetic Performances under Fluctuating Light in Arabidopsis thaliana.

In view of the current and expected future rise in atmospheric CO2 concentrations, we examined the effect of elevated CO2 on photoinhibition of photosystem I (PSI) under fluctuating light in Arabidopsis thaliana. At 400 ppm CO2, PSI showed a transient over-reduction within the first 30 s after transition from dark to actinic light. Under the same CO2 conditions, PSI was highly reduced after a transition from low to high light for 20 s. However, such PSI over-reduction greatly decreased when measured in 800 ppm CO2, indicating that elevated atmospheric CO2 facilitates the rapid oxidation of PSI under fluctuating light. Furthermore, after fluctuating light treatment, residual PSI activity was significantly higher in 800 ppm CO2 than in 400 ppm CO2, suggesting that elevated atmospheric CO2 mitigates PSI photoinhibition under fluctuating light. We further demonstrate that elevated CO2 does not affect PSI activity under fluctuating light via changes in non-photochemical quenching or cyclic electron transport, but rather from a rapid electron sink driven by CO2 fixation. Therefore, elevated CO2 mitigates PSI photoinhibition under fluctuating light at the acceptor rather than the donor side. Taken together, these observations indicate that elevated atmospheric CO2 can have large effects on thylakoid reactions under fluctuating light.

Hydrothermal synthesis of a novel nanolayered tin phosphate for removing Cr(iii).

In this work, an outstanding nanolayered tin phosphate with 15.0 Å interlayer spacing, Sn (HPO4)2·3H2O (SnP-H+), has been synthesized by conventional hydrothermal method and first used in the adsorptive removal of Cr(iii) from aqueous solution. A number of factors such as contact time, initial concentration of Cr(iii), temperature, pH, and ionic strength on adsorption were investigated by batch tests. Moreover, the isothermal adsorption characteristics and kinetic model of Cr(iii) onto SnP-H+ were studied. The results showed that the adsorption of Cr(iii) by SnP-H+ was in accordance with the Langmuir adsorption isotherm model and the pseudo-second-order kinetic model. The adsorption capacity of Cr(iii) onto SnP-H+ at temperature 40.0 °C and pH 3.0 could reach 81.1 mg g-1. And the distribution coefficient K d was 23.0 g L-1. Overall, experiments certified that SnP-H+ was an excellent adsorbent that can effectively remove Cr(iii) from aqueous solution.

Matrine ameliorates cognitive deficits via inhibition of microglia mediated neuroinflammation in an Alzheimer's disease mouse model.

Amyloid ß (Aß) induced microglial activation and attendant neuroinflammation play pivotal roles in Alzheimer's disease (AD) pathogenesis. Matrine is a natural anti-inflammation compound from the Chinese herbal medicine Sophora flavescens Ait. (Kushen). This study aimed to investigate the effects of matrine on memory deficit and neuroinflammation in an oligomeric Aß (oAß)-induced AD mice model. Whether microglial activation and NADPH oxidase were involved in these effects were further studied. Different doses of matrine (10, 20, or 40 mg/kg) were intragastrically administered once a day after intracerebroventricular oAß injection (2.5 µg/µl, 4 µl). 15 days after the oAß injection, behavioral experiments including novel object recognition (NOR) test and Morris water maze (MWM) test were performed. 21 days after the oAß injection, concentration of ROS, TNF-α, IL-1ß and IL-6 as well as expression of NADPH oxidase subunits gp91phox and p47phox in mice hippocampal tissues were assessed, and microglial activation were evaluated by Iba-1 immunohistochemical staining. Results of NOR test and MWM test revealed that oAß injection could remarkably impair learning and memory function in AD mice, and matrine administration could significantly ameliorate the impairment. ROS, TNF-α, IL-1ß and IL-6 levels increased after oAß injection, while matrine could significantly reduce the concentrations of these inflammatory factors. OAß induced protein expression of NADPH oxidase subunits gp91phox and p47phox were also significantly reduced by matrine. Iba-1 immunohistochemistry results showed less activated microglia in matrine-treated mice brain. These results indicate that matrine could ameliorate learning and memory impairment and neuroinflammation induced by oAß injection. These effects were found to be mediated through inhibition of microglial activation and NADPH oxidase expression in hippocampal tissue. The results suggest that matrine may be a valuable natural compound with therapeutic potential against AD.

Two-dimensional two-photon absorptions and third-order nonlinear optical properties of Ih fullerenes and fullerene onions.

The third order static and dynamic nonlinear optical (NLO) responses of Ih symmetry fullerenes (C60, C240, and C540) and fullerene onions (C60@C240 and C60@C240@C540) are predicted using the ZINDO method and the sum-over-states model. The static second hyperpolarizability of Ih symmetry fullerenes increases exponentially with fullerene size [from 10.00 × 10-34 esu in C60 to 3266.74 × 10-34 esu ≈ γ0(C60) × 92.63 in C540]. The external fields of strong third order NLO responses of Ih symmetry fullerenes change from ultra-violet (C60) to the visible region (C540) as the fullerene size increases. The outer layer fullerene in the fullerene onions has dominant contributions to the third order NLO properties of the fullerene onions, and the inter-shell charge-transfer excitations have conspicuous contributions to the third order NLO properties. The two-dimensional two-photon absorption spectra of C60 and C240 show that those fullerenes have strong two-photon absorptions in the visible region with short wavelength and in the ultra-violet region.

The Serine Carboxypeptidase-Like Gene SCPL41 Negatively Regulates Membrane Lipid Metabolism in Arabidopsis thaliana.

The Arabidopsis has 51 proteins annotated as serine carboxypeptidase-like (SCPL) enzymes. Although biochemical and cellular characterization indicates SCPLs involved in protein turnover or processing, little is known about their roles in plant metabolism. In this study, we identified an Arabidopsis mutant, bis4 (1-butanol insensitive 4), that was insensitive to the inhibitory effect of 1-butanol on seed germination. We cloned the gene that was defective in bis4 and found that it encoded an SCPL41 protein. Transgenic Arabidopsis plants constitutively expressing SCPL41 were generated, oil body staining and lipidomic assays indicated that SCPL41-overexpressing plants showed a decrease in membrane lipid content, especially digalactosyl diglyceride (DGDG) and monogalactosyl diglyceride (MGDG) contents, while the loss of SCPL41 increased the membrane lipid levels compared with those in wild-type plants. These findings suggested that SCPL41 had acquired novel functions in membrane lipid metabolism.

Integration of subcellular partitioning and chemical forms to understand silver nanoparticles toxicity to lettuce (Lactuca sativa L.) under different exposure pathways.

The current understanding of the biological impacts of silver nanoparticles (AgNPs) is restricted to the direct interactions of the particles with biota. Very little is known about their intracellular fate and subsequent toxic consequences. In this research we investigated the uptake, internal fate (i,e., Ag subcellular partitioning and chemical forms), and phytotoxicity of AgNPs in lettuce following foliar versus root exposure. At the same AgNP exposure concentrations, root exposure led to more deleterious effects than foliar exposure as evidenced by a larger extent of reduced plant biomass, elevated oxidative damage, as well as a higher amount of ultrastructural injuries, despite foliar exposure leading to 2.6-7.6 times more Ag bioaccumulation. Both Ag subcellular partitioning and chemical forms present within the plant appeared to elucidate this difference in toxicity. Following foliar exposure, high Ag in biologically detoxified metals pool (29.2-53.0% by foliar exposure vs. 12.8-45.4% by root exposure) and low Ag proportion in inorganic form (6.1-11.9% vs. 14.1-19.8%) potentially associated with AgNPs tolerance. Silver-containing NPs (24.8-38.6 nm, 1.5-2.3 times larger than the initial size) were detected in lettuce plants exposed to NPs and to dissolved Ag+, suggesting possible transformation and/or aggregation of AgNPs in the plants. Our observations show that the exposure pathway significantly affects the uptake and internal fate of AgNPs, and thus the associated phytotoxicity. The results are an important contribution to improve risk assessment of NPs, and will be critical to ensure food security.

Turnover of Glycerolipid Metabolite Pool and Seed Viability.

Hydration⁻dehydration cycles can frequently cause stress to seeds, but can also be used to improve germination. However, the molecular basis of the stress caused is poorly understood. Herein, we examine the effects of hydration⁻dehydration cycles on seed viability and profile the membrane glycerolipid molecular species. We find that seed viability was not affected during the first two cycles, but significantly decreased as further cycles were applied, until all viability was lost. The abundances of seven glycerolipid classes increased and decreased through hydration and dehydration, respectively, but the phosphatidic acid and diacylglycerol abundances changed in the opposite sense, while total glycerolipid contents remained constant. This suggests that during hydration⁻dehydration cycles, turnover of glycerolipid metabolite pools take place, while no significant lipid synthesis or degradation is involved. As further hydration⁻dehydration cycles occurred, lipid unsaturation increased, plastidic lipids decreased, and phosphatidylserine acyl chains lengthened. The latter two could be lethal for seeds. Our findings reveal a novel model of membrane lipid changes, and provide new insights into the responses of seeds to hydration⁻dehydration cycles.

Ramosissimin, a new flavonol from Tararix ramosissima, induces apoptosis in rheumatoid arthritis fibroblast-like synoviocytes.

Tamarix ramosissima is a traditional Chinese herbal medicine used for rheumatoid arthritis (RA) treatment in Northwest China. Chemical investigation of EtOH/H2O extracts of T. ramosissima led to the discovery of a new flavonol, ramosissimin (1), together with the known flavonoids compounds quercetin (2), quercetin-3'4'-dimethylether (3) and kaempferol (4). By means of high resolution electrospray ionization mass spectroscopy (HRESIMS) and 1D and 2D-NMR experiments, and after comparison with literature data, the structures of the compounds were determined. The effect of compound 1 on the viability of RA fibroblast-like synoviocytes (RA-FLS) was evaluated by MTT assay. Apoptosis-inducing effect of compound 1 in RA-FLS was further investigated by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay and activated caspase-3/7 level assessment using luminescent assay. The results revealed that ramosissimin displayed remarkable proliferation inhibitory effect in RA-FLS. Furthermore, compound 1 could significantly induce cellular apoptosis of RA-FLS and increase activated caspase-3/7 levels. It is suggested that ramosissimin may inhibit the proliferation of RA-FLS by inducing apoptosis.

Structure, stability, electronic, magnetic, and catalytic properties of monometallic Pd, Au, and bimetallic Pd-Au core-shell nanoparticles.

Bimetallic core-shell nanoparticles (CSNPs) often exhibit excellent and tunable properties, depending on their composition, sizes, morphology, atomic arrangement, thickness, and sequence of both core and shell. In this study, the geometrical structure, thermodynamic stability, chemical activity, electronic and magnetic properties, and catalytic activity in the hydrogen evolution reaction (HER) of 13- and 55-atom Pd, Au NPs, and Pd-Au CSNPs were systematically investigated using density functional theory calculations. The results showed that Au atoms prefer to segregate to the surface-shell, while Pd atoms were inclined to aggregate in the core region for bimetallic Pd-Au CSNPs; therefore, Pd@Au CSNPs with an Au surface-shell were thermodynamically more favorable than both the monometallic Pd/Au NPs and the Au@Pd CSNPs with a Pd surface-shell. The Pd surface-shell of the Au@Pd CSNPs displayed a positive charge, while the Au surface-shell of the Au@Pd CSNPs exhibited a negative charge due to the charge transfer in the Pd-Au CSNPs, resulting in that the d-band center of Au@Pd with the Pd surface-shell showed larger shift toward the Fermi level and higher chemical activity. The Pd@Au CSNPs with the Au surface-shell showed similar d-band curves and d-band centers with monometallic Au NPs. All 13-atom Pd, Au NPs, and Pd-Au CSNPs were magnetic, while the 55-atom NPs were non-magnetic with symmetry partial density of states' curves except for Pd55. Changing the location of Pd and Au atoms in the Pd-Au CSNPs influenced their total magnetic moments. In addition, an opposite trend was found: small 13-atom NPs with a Pd surface-shell showed superior HER activity to the ones with an Au surface-shell, while large 55-atom NPs with an Au surface-shell possessed higher HER activity than the ones with a Pd surface-shell.

Two-dimensional second-order nonlinear optical spectra: landscape of second-order nonlinear optics.

The landscape of second-order nonlinear optical (2nd NLO) responses of a system can be depicted as two-dimensional second-order nonlinear optical spectra in a range of external fields, and this is difficult to be realized in experiment for a wide range of external fields. In the present study, an efficient method for application of sum-over-states model to simulate electronic two-dimensional NLO (2DNLO) spectra has been developed, and techniques to analyze NLO response-structure correlation have been proposed. This 2DNLO method has been applied to simulate the 2DNLO spectra of a series of typical electron push-pull chromophores under external fields of up to 5.00 eV. The correlation between the NLO properties and structure has been disclosed, and a further strategy to enhance the NLO properties of push-pull chromophores has been proposed.

Interface and interaction of graphene layers on SiC(0001[combining macron]) covered with TiC(111) intercalation.

It is important to understand the interface and interaction between the graphene layer, titanium carbide [TiC(111)] interlayer, and silicon carbide [SiC(0001[combining macron])] substrates in epitaxial growth of graphene on silicon carbide (SiC) substrates. In this study, the fully relaxed interfaces which consist of up to three layers of TiC(111) coatings on the SiC(0001[combining macron]) as well as the graphene layers interactions with these TiC(111)/SiC(0001[combining macron]) were systematically studied using the density functional theory-D2 (DFT-D2) method. The results showed that the two layers of TiC(111) coating with the C/C-terminated interfaces were thermodynamically more favorable than one or three layers of TiC(111) on the SiC(0001[combining macron]). Furthermore, the bonding of the Ti-hollow-site stacked interfaces would be a stronger link than that of the Ti-Fcc-site stacked interfaces. However, the formation of the C/Ti/C and Ti/C interfaces implied that the first upper carbon layer can be formed on TiC(111)/SiC(0001[combining macron]) using the decomposition of the weaker Ti-C and C-Si interfacial bonds. When growing graphene layers on these TiC(111)/SiC(0001[combining macron]) substrates, the results showed that the interaction energy depended not only on the thickness of the TiC(111) interlayer, but also on the number of graphene layers. Bilayer graphene on the two layer thick TiC(111)/SiC(0001[combining macron]) was thermodynamically more favorable than a monolayer or trilayer graphene on these TiC(111)/SiC(0001[combining macron]) substrates. The adsorption energies of the bottom graphene layers with the TiC(111)/SiC(0001[combining macron]) substrates increased with the decrease of the interface vertical distance. The interaction energies between the bottom, second and third layers of graphene on the TiC(111)/SiC(0001[combining macron]) were significantly higher than that of the freestanding graphene layers. All of these findings provided insight into the growth of epitaxial graphene on TiC(111)/SiC(0001[combining macron]) substrates and the design of graphene/TiC/SiC-based electronic devices.

Tamaractam, a New Bioactive Lactam from Tamarix ramosissima, Induces Apoptosis in Rheumatoid Arthritis Fibroblast-Like Synoviocytes.

Chemical investigation of Tamarix ramosissima Ledeb, a traditional herbal medicine used for rheumatoid arthritis (RA) treatment in northwest China, led to the discovery of a new phenolic aromatic rings substituted lactam, tamaractam (1), together with the previously reported compounds cis-N-feruloyl-3-O-methyldopamine (2) and trans-N-feruloyl-3-O-methyldopamine (3). The structures of the compounds were determined by high resolution electrospray ionization mass spectroscopy (HRESIMS) and 1D and 2D-NMR experiments, as well as comparison with the literature data. The effects of the three compounds on the viability of RA fibroblast-like synoviocytes (RA-FLS) were assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Pro-apoptosis effect of compound 1 in RA-FLS was further investigated by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, activated caspase-3/7 level assessment using luminescence assay, and sub-G1 fraction measurement using flow cytometry. It was found that these three compounds displayed variable proliferation inhibitory activity in RA-FLS, and compound 1 exhibited the strongest effect. Compound 1 could remarkably induce cellular apoptosis of RA-FLS, increase activated caspase-3/7 levels, and significantly increase sub-G1 fraction in the cell cycle. The results suggested that compound 1 may inhibit the proliferation of RA-FLS through apoptosis-inducing effect, and these compounds may contribute to the anti-RA effect of T. ramosissima.

Vasorelaxation Effect of Estrone Derivate EA204 in Rabbit Aorta.

Estrogen and its derivatives exert vascular protective effects, but the underlying mechanisms remain to be studied fully. Objective. To investigate the vasorelaxation effect and related mechanisms of an estrone derivate EA204[3-(2-piperidin-1-yl)-ethoxy-estra-1, 3, 5 (10)-trien-17-one] on isolated arterial preparation from rabbit thoracic aorta. Methods. Aortic rings from rabbit thoracic aorta were prepared and held in small organ bath filled with Krebs solution; tension change was recorded by a multichannel physiological signal collection and handling system. Results. EA204 (10(-5) to 10(-3) M) induced a concentration-dependent relaxation of aortic rings with endothelium and without endothelium. In denuded arterial preparations, EA204 had a potent relaxing effect on isolated arterial preparations contracted with phenylephrine, norepinephrine, and high-K(+) solution or BaCl2. Mechanism study indicates that EA204 relaxes aortic rings by inhibiting Ca(2+) channels (both receptor-operating Ca(2+) channels and the voltage-dependent Ca(2+) channels were involved) to decrease extracellular Ca(2+) influx and intracellular Ca(2+) release. EA204 is different from verapamil, which is a noncompetitive inhibitor of Ca(2+) channels. In addition, K(+) channels opening may contribute to this vasorelaxation effect. Conclusion. EA204 had a potent endothelium-independent relaxing effect on isolated arterial preparation by inhibiting Ca(2+) channels and opening K(+) channels. The results suggest that EA204 is a potential compound for treatment of cardiovascular diseases in postmenopausal women.

Structure and chain conformation of a neutral intracellular heteropolysaccharide from mycelium of Paecilomyces cicadae.

A neutral heteropolysaccharide (PCIPS2) was isolated and purified from mycelium of Paecilomyces cicadae, which was investigated to be mainly composed of D-mannose, L-rhamnose, 3-O-methyl-D-galactose, D-glucose and D-galactose with a molar ratio of 47.9:3.1:6.4:0.9:0.8. It had a backbone of 1,4-linked α-L-Rhap residues and 1,6-linked α-D-Manp residues with branches at O-3 of α-D-Manp residues. Its side chain was comprised of minor terminal ß-D-glucose and 1,4-linked α-3-O-Me-D-Galp residues terminated by α-D-galactose. Furthermore, its chain information on the values of weight-average molar mass (Mw), root mean square radius ([Formula: see text]), hydrodynamic radius (Rh) and intrinsic viscosity ([η]) for PCIPS2 were analyzed to be 3.09 × 10(4)g/mol, 7.8 nm, 3.6 nm and 8.5 mL/g, respectively. The structural exponent α of 0.57 indicated that PCIPS2 existed as a flexible chain conformation with a coil-like structure in 0.1M NaNO3 at 25 °C. In terms of known theory for worm-like chains, the model parameters for PCIPS2 were as following: molar mass per unit contour length (ML) = 379 nm(-1), persistence length (q) = 0.74 nm and hydrodynamic diameter of cylinder (d) = 0.82 nm, which were further evidenced by atomic force microscopy (AFM).