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Abstract: Soil solarization is a method of soil heating used to eradicate plant pathogens and weeds that involves passive solar heating of moist soil mulched (covered) with clear plastic tarp. Various types of organic matter may be incorporated into soil prior to solarization to increase biocidal activity of the treatment process. Microbial activity associated with the decomposition of soil organic matter may increase temperatures during solarization, potentially enhancing solarization efficacy. However, the level of organic matter decomposition (stability) necessary for increasing soil temperature is not well characterized, nor is it known if various amendments render the soil phytotoxic to crops following solarization. Laboratory studies and a field trial were performed to determine heat generation in soil amended with compost during solarization. Respiration was measured in amended soil samples prior to and following solarization as a function of soil depth. Additionally, phytotoxicity was estimated through measurement of germination and early growth of lettuce seedlings in greenhouse assays. Amendment of soil with 10%(g/g) compost containing 16.9mg CO2/gdry weight organic carbon resulted in soil temperatures that were 2–4°C higher than soil alone. Approximately 85% of total organic carbon within the amended soil was exhausted during 22days of solarization. There was no significant difference in residual respiration with soil depth down to 17.4cm. Although freshly amended soil proved highly inhibitory to lettuce seed germination and seedling growth, phytotoxicity was not detected in solarized amended soil after 22days of field solarization. [Copyright &y& Elsevier]

Abstract: Sulfated polysaccharides exerted potent biological property which was relative to degree of sulfation (DS), M w, substitution position and chain conformation. In the present study, sulfated derivatives of Artemisia sphaerocephala polysaccharide (ASP) with different DS were synthesized by chlorosulfuric acid/pyridine method. FT-IR and 13C NMR analysis indicated that C-6 substitution was predominant in sulfated ASP (SASP) compared with other positions at C-2. In the sulfation reaction, a sharp decrease in M w was observed in SASP. The d f values from 1.96 to 2.77 indicated that the –SO3H groups leading to the relatively expanded conformation of SASP. Antioxidant assays showed that SASP had better antioxidant activities. The data obtained in vitro models indicated that high DS and moderate M w showed the best antioxidant capacities. [Copyright &y& Elsevier]

Various chiral oxacyclic dienes were synthesized via enyne metathesis using Grubbs catalyst (PCy3)2Cl2Ru&z.dbnd;CHPh. A series of substrates bearing a 1,2-diol skeleton was prepared from (2S)-(benzyloxy)-propanal. The enyne metathesis proceeds smoothly in CH2Cl2 at 23°C with a low loading of catalyst (2.0 mol%) under ethylene gas (1–2.5 atm), giving good yields of products without epimerization at any stereogenic carbon. Heating compound 5 comprising a disubstituted alkyne in benzene (80°C) under nitrogen resulted in formation of two diastereomers via epimerization of the primary product. The epimerization occurs at the oxacyclic carbon rather than the benzyl carbon. Diels–Alder reactions of chiral oxacyclic dienes 19 and 22 with maleic anhydride, maleimide and benzoquinone proceeded with high diastereoselectivities, yielding a single cycloadduct efficiently at ambient conditions. The structures of Diels–Alder adducts were determined by 1H NOE NMR spectra. The cycloadducts were formed via the approach of dienophiles to the diene in endo mode and opposite the substituent of the stereogenic center. The cycloadducts 29 and 31 were transformed into enantiopure tricyclic furans 35 and 38 after transformation of the (2S)-(silyloxy)ethyl group into an acetate group. [Copyright &y& Elsevier]

Eight novel transition metal carbides, nanolaminated (Cr 2/3 R 1/3) 2 GaC (R=Y, Tb, Dy, Ho, Er, Tm, Yb and Lu) with R in-plane chemical ordered occupation, have been synthesized with mainly Cmcm orthorhombic structure and monotonously decreased lattice parameters due to lanthanide contraction. Stacking disorderings and high-density slidings within c plane have been observed. Two characteristic in-plane sliding, along [100] or [ 1 ¯ 30 ] o directions have been analyzed with former one leading into the structural evolution between Cmcm and C2/c symmetry. Such an atomic scale co-existence of Cmcm and C2/c structures is explained by more negative charge for Ga and anisotropic bonding with Ga compared with A=Al case. Thus, the Vickers hardness, fracture strength and increased wear depth are reduced in representative (Cr 2/3 Lu 1/3) 2 GaC i -MAX bulk compared with the (Cr 2/3 Lu 1/3) 2 AlC counterpart. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, selenized Artemisia sphaerocephala polysaccharides (SePAS) were obtained through employing N -methyl-2-pyrrolidone hydrosulfate as catalyst, which showed a maximum Se content enhanced to 8744 μg/g. FT-IR, 1D/2D NMR, X-ray photoelectron spectroscopy (XPS) and size-exclusion chromatograph analysis exhibited that Se had been successfully introduced into PAS and existed in the form of selenate group (Se4+) with the substitution position at C-6. Furthermore, immunostimulating assays indicated that SePAS with high Se content exhibited stronger immunomodulatory activities by upregulated the phosphorylation level of ERK, JNK and p38, thus enhancing RAW264.7 cells proliferation, phagocytosis, levels of interleukin-6, nitric oxide, tumor necrosis factor and interleukin-1β. The current outcome suggested that Se content might be a critical factor affecting the immunomodulatory effects of selenized PAS on macrophage RAW264.7. • [HNMP]HSO 4 enhanced selenylation efficiency of Artemisia sphaerocephala polysaccharides. • The chemical structure of selenized A. sphaerocephala polysaccharides was fully characterized. • High Se content increased the immunomodulatory activities. • Selenized A. sphaerocephala polysaccharide exhibited immunomodulatory activities by activating MAPKs signaling pathways. [ABSTRACT FROM AUTHOR]

• Inspired by the mussel foot protein and chitosan-based macromolecular adhesives, a series of chitosan- graft -polypeptides were synthesized, these copolymers have excellent adhesivity. • The maximum of the lap-shear adhesion strength on the porcine skin and aluminum sheet were 195.97 kPa and 3080 kPa respectively, and the maximum of tensile adhesion strength of bone was 642.70 kPa. • These chitosan-graft-polypeptides can be used not only as soft and bone tissue adhesives but also as hemostatic materials and metal adhesives. Inspired by the mussel foot protein and chitosan-based macromolecular adhesives, a series of chitosan- graft -polypeptides were synthesized by ring-opening polymerization of three N -carboxyanhydrides (NCAs) - 3,4-dihydroxyphenylalanine- N -carboxyanhydride (DOPA-NCA), cysteine-NCA (Cys-NCA) and arginine-NCA (Arg-NCA) - using partial-NH 2 -protected chitosan as an initiator. These copolymers demonstrated good biodegradability and low cytotoxicity. The results of lap-shear adhesion test showed that the maximum lap-shear adhesion strength on the porcine skin and aluminum sheet were 195.97 ± 21.1 kPa and 3080 ± 320 kPa, respectively, and the maximum tensile adhesion strength on bone was 642.70 ± 61.1 kPa. The rat experiment in vivo showed that these copolymers exhibited good hemostatic performance and can promote the healing of skin wound and bone fracture. It is expected that thesecopolymeric adhesives will have broad applications in hemostasis and soft tissue adhesions. [ABSTRACT FROM AUTHOR]

Use of microwave radiation is one of the most potential techniques in polysaccharide derivatives synthesis due to its advantages such as higher yields, milder reaction conditions and shorter reaction times. This study was aimed at producing sulfated polysaccharides by microwave irradiation using polar reagents and solvent. Six sulfated Artemisia sphaerocephala polysaccharide derivatives (SPAS) were obtained by using chlorosulfuric acid/pyridine method in the reaction duration range of 15–300 min at a fixed microwave power of 100W. Synthesis of SPAS under microwave filed was highly effective and characterized by time saving and high degrees of substitution (DS). The chemical structure of SPAS was confirmed by FT-IR and 13 C NMR that sulfation had occurred and the substitution position was mainly at C-6. Size-exclusion chromatograph combined with multi-angle laser photometer (SEC-MALLS) data indicated that short reaction time minimized acid-catalyzed degradation of polysaccharide chains. AFM observation demonstrated that low- M W derivative exhibited aggregation of polysaccharide chain as irregular spherical lumps. In anti-tumor activity assays, sulfation of PAS significantly improved the capacity to inhibit tumor cells growth by arresting the cell cycle progress in specific phases. It could be concluded that M W and molecular mass distribution had much greater influence on anti-tumor activities of SPAS against human non-small cell lung cancer A549 cells, human hepatocellular carcinoma HepG2 cells and human cervical cancer Hela cells. Microwave-assisted synthesis might possess widespread application in preparation of new polysaccharide derivatives with rich variety of structural features and bioactivities. [ABSTRACT FROM AUTHOR]

In this study, a sulfated Artemisia sphaerocephala polysaccharide (ASPs) was prepared and its antitumor activity was evaluated in tumor cells and Hepatoma 22 (H22) tumor-bearing mice. In vitro experiments, ASPs significantly inhibited the growth of HepG2 and Hela cells with the IC 50 values of 172.03 and 161.42 μg/mL, respectively. Moreover, no direct cytotoxicity against mouse fibroblast L929 normal cells was observed in vitro. After oral administration for 12 days, the tumor growth was significantly suppressed by ASPs at the doses of 200 mg/kg (inhibition rate of 60.85%). Results of tumor histological morphology and cell cycle analysis showed that ASPs could arrest H22 cells at S phase and promote cell apoptosis. Additionally, immunohistochemical analysis demonstrated that ASPs caused the down-regulation of mutant p53 protein expression in a dose-dependent manner. Therefore, these findings proposed new insight into antitumor properties of sulfated polysaccharide as a promising agent in cancer treatment. [ABSTRACT FROM AUTHOR]

Abstract: To estimate the biological risks from space radiation encountered by cosmonauts in outer space, the effects from whole-body exposure to carbon ions or X-rays irradiations at 0, 0.39, 0.55 and 1Gy at a dose rate of 0.2Gy/min were investigated in BALB/c mice. The relative thymus and spleen weights were measured at 24h after exposure, and the cell cycle distribution and percentage of apoptosis of thymocytes and spleen and peripheral blood lymphocytes were determined by flow cytometry. The data showed that exposure to carbon ions delayed cell progression of peripheral blood lymphocytes in S-phase, and delayed thymocytes and spleen lymphocytes in G0/G1-phase. Apoptosis of thymocytes and peripheral blood lymphocytes induced by carbon ions increased more rapidly with dose than was the case for X-rays. There were some differences between the relative weight loss of the thymus and the spleen with increasing dose of either carbon ions or X-rays. The results obtained provide evidence of dose- and organ-specific differences induced by carbon ions compared to X-rays, with increased apoptosis in peripheral blood lymphocytes and thymocytes, but not spleen lymphocytes. Our data may suggest that further work would be of interest to estimate risk of changes in immune function during particle radiation exposures in space travel. [Copyright &y& Elsevier]