STUDY ON POLYANILINE FILM WITH HIGH-DENSITY AND HIGH MECHANICAL STRENGTH

Free-standing film of polyaniline with excellent mechanical and electrical properties has been successfully prepared by using the solution-casting method. The results show that its tensile strength, Young's modulus and elongation at break are about 87.9 MPa, 1563.9 MPa and 10.2%, respectively. It is essential that the soluble polyaniline should be appropriately treated in some suitable organic solvents before making a free-standing film. Films having lustrous, smooth surface, high density and good flexibili...

A genetic linkage map of Pacific white shrimp (Litopenaeus vannamei): sex-linked microsatellite markers and high recombination rates

Pacific white shrimp (Litopenaeus vannamei) is the leading species farmed in the Western Hemisphere and an economically important aquaculture species in China. In this project, a genetic linkage map was constructed using amplified fragment length polymorphism (AFLP) and microsatellite markers. One hundred and eight select AFLP primer combinations and 30 polymorphic microsatellite markers produced 2071 markers that were polymorphic in either of the parents and segregated in the progeny. Of these segregating markers, 319 were mapped to 45 linkage groups of the female framework map, covering a total of 4134.4 cM; and 267 markers were assigned to 45 linkage groups of the male map, covering a total of 3220.9 cM. High recombination rates were found in both parental maps. A sex-linked microsatellite marker was mapped on the female map with 6.6 cM to sex and a LOD of 17.8, two other microsatellite markers were also linked with both 8.6 cM to sex and LOD score of 14.3 and 16.4. The genetic maps presented here will serve as a basis for the construction of a high-resolution genetic map, quantitative trait loci (QTLs) detection, marker-assisted selection (MAS) and comparative genome mapping.

Modern sedimentary environments and dynamic depositional systems in the southern Yellow Sea

Based on analyses of more than 600 surface sediment samples together with large amounts of previous sedimentologic and hydrologic data, the characteristics of modern sedimentary environments and dynamic depositional systems in the southern Yellow Sea (SYS) are expounded, and the controversial formation mechanism of muddy sediments is also discussed. The southern Yellow Sea shelf can be divided into low-energy sedimentary environment and high-energy sedimentary environment; the low-energy sedimentary environment can be further divided into cyclonic and anticyclonic ones, and the high-energy environment is subdivided into high-energy depositional and eroded environments. In the shelf low-energy environments, there developed muddy depositional system. In the central part of the southern Yellow Sea, there deposited the cold eddy sediments under the actions of a meso-scale cyclonic eddy (cold eddy), and in the southeast of the southern Yellow Sea, an anticyclonic eddy muddy depositional system (warm eddy sediment) was formed. These two types of sediments showed evident differences in grain size, sedimentation rate, sediment thickness and mineralogical characteristics. The high-energy environments were covered with sandy sediments on seabed; they appeared mainly in the west, south and northeast of the southern Yellow Sea. In the high-energy eroded environment, large amounts of sandstone gravels were distributed on seabed. In the high-energy depositional environment, the originally deposited fine materials (including clay and fine silt) were gradually re-suspended and then transported to a low-energy area to deposit again. In this paper, the sedimentation model of cyclonic and anticyclonic types of muddy sediments is established, and a systematic interpretation for the formation cause of muddy depositional systems in the southern Yellow Sea is given.

P wave velocity of the pumice from the Okinawa Trough at high temperature and high pressure.

P wave velocity of the pumice sample from the middle Okinawa Trough and andesite sample from vicinity Yingdao volcanic island, Kyushu Japan were measured at temperature (from room temperature to 1500 C) and pressure (from room pressure to 2.4GPa) using a multi-anvil pressure apparatus called the YJ-3000 press. The measured data shows that at low temperature and low pressure (<1GPa, <800degreesC), the P wave velocity of pumice is lower than that of andesite, while at high temperature and high pressure (>1GPa, >800degreesC) the P wave velocity of pumice and andesite. becomes consistent (5.9km/s). The paper points out that 1GPa/800degreesC is the point of thermodynamic phase transformation Okinawa Trough pumice and vicinity andesite, and the point is deeper than 18km.

An efficient combination of supercritical fluid extraction and high-speed counter-current chromatography to extract and purify homoisoflavonoids from Ophiopogon japonicus (Thunb.) Ker-Gawler

Supercritical fluid extraction (SFE) was used to extract homoisoflavonoids from Ophiopogon japonicus (Thunb.) Ker-Gawler. The optimization of parameters was carried out using an orthogonal test L-9 (3)(4) including pressure, temperature, dynamic extraction time and the amount of modifier. The process was then scaled up by 100 times with a preparative SFE system under the optimized conditions of 25 MPa, 55 degrees C, 4.0 h and 25% methanol as a modifier. Then crude extracts were separated and purified by high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of n-hexane/ethyl acetate/methanol/ACN/water (1.8:1.0:1.0:1.2:1.0 v/v). There three homoisoflavonoidal compounds including methylophiopogonanone A 6-aldehydo-isoophiopogonone A, and 6-formyl-isoophiopogonanone A, were successfully isolated and purified in one step. The collected fractions were analyzed by HPLC. In each operation, 140 mg crude extracts was separated and yielded 15.3 mg of methylophiopogonanone A (96.9% purity), 4.1 mg of 6-aldehydo-isoophiopogonone A (98.3% purity) and 13.5 mg of 6-formyl-isoophiopogonanone A (97.3% purity) respectively. The chemical structure of the three homoisoflavonoids are identified by means of ESI-MS and NMR analysis.

Preparation of high-molecular weight and high-sulfate content chitosans and their potential antioxidant activity in vitro

The influence of molecular weight and substitution degree of sulfated polysaccharides on their biological activity is considered in majority of works involving the anticoagulant or antiviral properties of these substances. Therefore, the present paper describes the effect of preparation conditions of sulfated chitosans on their molecular weight and sulfur content, such as different reaction time, acid solvent and temperature. Foregoing literature expounded the action of dichloroacetic acid (DCAA) as acid solvent in homogeneous reaction. However, DCAA is expensive and noxious, therefore, in the present paper cheap and non-noxious formic acid (88%) was in place of DCAA. Furthermore, during reaction formic acid was not dehydrated. Under formic acid we obtained the satisfying results that was higher yield and equivalent sulfur contents compared to DCAA. IR and C-13 NMR spectrums proved the structure of the resultant obtained under formic acid or DCAA to be same. Now, it has not been reported for formic acid as acid solvent in homogeneous reaction of chitosan sulfatation. In this present paper, we also determined antioxidant activity of high-molecular weight and high-sulfate-content chitosans (HCTS). The results showed that HCTS could scavenge superoxide and hydroxyl radical. Its IC50 is 0.012 and 3.269 mg/mL, respectively. It had obviously reducing power and slight chelating activity. The data obtained in in vitro models clearly establish the antioxidant potency of HCTS. It is a potential antioxidant in vitro. (C) 2005 Elsevier Ltd. All rights reserved.

Preparation of low-molecular-weight and high-sulfate-content chitosans under microwave radiation and their potential antioxidant activity in vitro

In the present paper microwave radiation has been used to introduce N-sulfo and O-sulfo groups into chitosan with a thigh degree of substitution and low-molecular weight. The sulfation of chitosan was performed in microwave ovens. It was found that microwave heating is a convenient way to obtain a wide range of products of different degrees of substitution and molecular weight only by changing reaction time or/and radiation power. Moreover, microwave radiation accelerated the degradation of sulfated chitosan, and the molecular weight of sulfated chitosan was considerably lower than that obtained by traditional heating. There are no differences in the chemical structure of sulfated chitosan obtained by microwave and by conventional technology. FTIR and C-13 NMR spectral analyses demonstrated that a significantly shorter time is required to obtain a satisfactory degree of substitution and molecular weight by microwave radiation than by conventional technology. In this present paper, we also determined antioxidant activity of low-molecular-weight and high-sulfate-content chitosans (LCTS). The results showed LCTS could scavenge superoxide and hydroxyl radical. Its IC50 is 0.025 and 1.32mg/mL, respectively. It is a potential antioxidant in vitro. (C) 2004 Published by Elsevier Ltd.

The experimental studies on electrical conductivities and P-wave velocities of anorthosite at high pressure and high temperature

National Science Foundation of China (No. 10032040 and No. 49874013) and Joint Earthquake Science Foundation of China (No. 101119).