Experimental Study on the Blast Resistance Performance of FRP Grid & Mortar Reinforced Concrete Arch Structure.

In order to verify the feasibility of using FRP grid and mortar reinforcement technology to enhance the blast resistance of concrete arch structures, this paper designed and fabricated FRP grid and mortar reinforced concrete arch structures and conducted blast resistance tests in the field. A detailed design of anti-explosion scheme was carried out before the experiment. The tests were conducted to observe the structural cracking, concrete collapse, and reinforcement peeling of FRP grid and mortar reinforced concrete arch under the explosion. In order to compare the anti-explosion performance with the protective arch structures in other literature, the explosion of 2 kg TNT with a blast distance of 600 mm was selected. After the explosion, it was found that the blast resistance of the FRP grid and mortar reinforced concrete arch was significantly higher than that of the unreinforced arch, and the concrete arch reinforced with FRP grid and mortar has a better damage patterns and improved blast resistance performance than that of the FRP and steel plate reinforced arch. According to the research results, the FRP grid and mortar composite reinforcement technology can be used to enhance the blast resistance of arch structures in protection projects.

Anticoagulant activity of a sulfated Lachnum polysaccharide in mice with a state of hypercoagulability.

A sulfated polysaccharide, designated as SLEP-1, was obtained after sulfation of the exopolysaccharide (LEP-1) which was isolated from Lachnum. The degree of substitution (DS) of sulfate group of SLEP-1 was 1.97. SEM images of SLEP-1 revealed laminated structure in mesh. UV, FT-IR and 13C NMR spectra indicated that the LEP-1 was sulfated successfully. The result of the anticoagulant activity in vitro showed that both of LEP-1 and SLEP-1 could effectively prolong activated partial thromboplastin time (APTT) and thrombin time (TT) of the normal mice plasma, in which SLEP-1 was more effectively than those of LEP-1, and dose-effect relationships were found. According to the bleeding time (BT), clotting time (CT), APTT, PT, prothrombin time (TT), fibrinogen (FIB), AT-III activity and FXa concentration of the hypercoagulable mice, it indicated that SLEP-1 (30mg·kg-1 and 90mg·kg-1) had strong inhibitory effect on intrinsic coagulation pathway, which could also enhance fibrinolytic activity. It may constitute an anticoagulant drug of interest in anticoagulant therapy.

Preparation, characterization and bioactivities of derivatives of an exopolysaccharide from Lachnum.

An exopolysaccharide, obtained previously LEP-2b from Lachnum YM405, was phosphated and sulfated successfully. The derivatives named PLEP-2b and SLEP-2b, respectively, and their respective degree of substitution were 0.174 and 0.431. Phosphate groups -PO3H2 substituted at C-6 of 1,4-ß-D-mannopyranose, C-5 of 2,6-ß-d-1-OMe-mannofuranoside, C-3 of 1,6-ß-D-galactopyranose, C-2 of 1-ß-D-glucopyranose, and C-6 of 1,2-α-D-rhampyranose, while sulfate groups SO3H were mainly at C-6 of 1,4-ß-D-Manp, C-6 of 1-ß-D-Glcp and C-6 of 1,2-α-D-Rhap. Compared with LEP-2b, the scavenging effects of the derivatives, on hydroxyl radical and superoxide anion were significantly increased after the modifications, except for reducing power. Meanwhile, phosphorylated and sulfated modifications remarkably strengthened the inhibiting effect of LEP-2b on the proliferation of CT-26 murine colon carcinoma, Lewis lung carcinoma and human hepatocellular carcinoma HepG2 cells. The derivatives significantly enhanced the antioxidant and antitumor activities in vitro. Compared with sulfation, phosphorylation improved the inhibitory effect more contraposingly on some specific tumor cells.

Carboxymethylation of an exopolysaccharide from Lachnum and effect of its derivatives on experimental chronic renal failure.

Carboxymethylated polysaccharide CLEP-1b was prepared from a single component (LEP-1b) of Lachnum YM281 exopolysaccharides by molecular modification with a degree of substitution (DS) of 0.286. Infrared result proved that the carboxymethylation of LEP-1b succeeded and (13)C NMR result showed that the carboxymethyl group (CH2COOH) was chemically linked to an oxygen (O) atom of the hydroxyl on C-3 of LEP-1b. LEP-1b could improve the histopathological status of kidney and significantly reduce the contents of serum creatinine (Scr) and blood urea nitrogen (BUN), and increase the contents of total protein and albumin. It could also enhance the activity of SOD, GSH-PX, CAT, GSH and decrease MDA contents in the nephridial and hepatic tissues. What's more, CLEP-1b showed more significant effects than LEP-1b at the same dosage. The research indicated that LEP-1b and CLEP-1b could mitigate the chronic renal failure of mice and the effects were closely associated with antioxidant activity.

Purification, characterization and promoting effect on wound healing of an exopolysaccharide from Lachnum YM405.

An exopolysaccharide (LEP-2b) with molecular weight of 2.8×10(4)Da was isolated from Lachnum YM405 and purified by DEAE-cellulose 52, Sepharose CL-6B chromatographic column. It consisted of rhamnose (Rha), mannose (Man), glucose (Glc) and galactose (Gal) in a molar ratio of 1.0:5.0:11.5:12.5. Its backbone consisted of →4)-ß-d-Manp-(1→, →2)-α-d-Rhap-(1→, →6)-ß-d-Glcp-(1→, and →6)-α-d-Galp-(1→, and three types of branches were composed of →6)-α-d-1-OMe-Manf-(2→, →6)-ß-d-1-OMe-Manf-(2→, →1)-α-d-Galp-(6→, →1)-ß-d-Galp-(6→, and →1)-ß-d-Glcp, which were at O-3 of 1,3,6-linked α-d-Manp and O-2, O-3 of the same 1,2,3,6-linked ß-d-Glcp in the backbone respectively. LEP-2b ointment significantly accelerated the decrustation of the wounded skin, shortened the healing time and increased the water and hydroxyproline contents of the healed skin. Combined with the results of macroscopic and histological observations, we deemed that LEP-2b could inhibit inflammatory reaction of scalded skin, accelerate tissue repair and re-epithelialization, thereby playing a positive role in promoting wound healing.

Phosphorylation and anti-tumor activity of exopolysaccharide from Lachnum YM120.

Phosphorylated polysaccharide PLEP-1a, with the PO4³â» content of 6.39%, was prepared from LEP-1a by phosphorylation. IR, (13)C NMR and (31)P NMR results of PLEP-1a showed that the original basic structure of the polysaccharide was not changed, and the -H2PO3 group was linked at C6 of LEP-1a. The results of anti-tumor experiments in vivo showed that 100 mg/kg and 400 mg/kg of LEP-1a could significantly improve the food consumption, body weight, tumor inhibition rate and thymus index of S180 sarcoma mice, and increase the levels of SOD, IL-2 and TNF-α in mice blood serum, indicating that LEP-1a had an excellent anti-tumor activity. Furthermore, PLEP-1a had a significantly enhanced inhibitory effect on S180 sarcoma mice than LEP-1a, suggesting that phosphorylation is an effective way of improving the biological activity of LEP-1a.