DEVELOPMENT OF A CHEMILUMINESCENT ELISA FOR DETERMINING OKADAIC ACID IN SHELLFISH

ABSTRACT

An indirect competitive enzyme‐linked immunosorbent assay with chemiluminescent (CL‐ELISA) detection for okadaic acid (OA) in mussel muscle was developed. A hybridoma cell line secreting monoclonal antibody against OA was established after immunization of BALB/c mice with artificially synthesized OA‐bovine serum albumin as antigen. Luminol solution was used as the substrate for horseradish peroxidase. The detection limit was 0.175 ng/g. The range of average fortified recovery was 91.8–102.6% when OA was spiked in mussel muscle at levels of 50, 160 and 800 µg/kg. The standard curve for OA showed good linearity over the concentration range of 0.08125–20 ng/mL. The cross‐reactivity with dinophysistoxin1 and saxitoxin was 51.82 and 0%, respectively. In a residue study, the results obtained by CL‐ELISA correlated well within those obtained using the commercial ABRAXIS kit (ABRAXIS, Warminster, PA). The developed method is therefore suitable for detecting the residues of OA in shellfish.

PRACTICAL APPLICATIONS

Diarrhetic shellfish poisoning is a gastrointestinal syndrome that occurs in humans following the consumption of bivalve mollusks contaminated with OA with the main symptoms of diarrhea, nausea, vomiting and abdominal pain. OA widely exists at marine products and it is very important to develop a technique to monitor this toxin. In this study, a sensitive competitive indirect enzyme‐linked immunosorbent assay with chemiluminescence for determination of OA in mussel soft tissues was investigated. Chemiluminescent ELISA (CL‐ELISA) is a good alternative method for screening samples. This technique has the potential to improve the sensitivity of the immunoassays by at least two to three orders of magnitude compared with conventional colorimetric detection.     

PARALLEL FRAME SYNCHRONOUS SCHEME FOR STM-1 IN SDH NETWORKS

This paper presents a novel parallel processing-based frame synchronous methodology for 155·520 Mbit/s high speed networks according to ITU-T Recommendations G.707, G.708 and G.709. This scheme is expected to relax operating speed requirements of the circuits used in the system. The proposed methodology can be implemented using off-the-shelf low-rate integrated circuits (ICs). The performance of the devised methodology is analysed and found to be similar to that of traditional approaches. Finally, the proposed scheme is efficient and easy to implement at low cost without sacrificing performance.     

某细粒嵌布铜锌锡多金属矿全浮选试验研究

针对某细粒嵌布锡铜锌多金属矿进行了浮选试验研究。原矿中可回收矿物锡石的嵌布粒度在0.037 mm以下,属于微细粒嵌布,原矿中黄铜矿、闪锌矿的嵌布状态为中细粒嵌布。微细粒嵌布的锡石重选效果较差,研究摒弃了常规的锡石硫化矿石的浮—重联合工艺,在合理的药剂制度下确定了磁选除铁—硫化矿浮选除硫—锡石浮选的全浮选流程,获得了良好的选矿指标。     

耐热橡胶

橡胶作为高分子材料，其主链的化学成分是烃类，易燃而不耐热，所以橡胶的耐热仅仅是相对而言的，不能和真正的耐热材料（如石棉）相提并论。但各种产品出于实际应用的需要，对耐热性提出了越来越多的要求。而经过材料选择、配方设计，橡胶的耐热等级的上限也在逐步提升。耐热橡胶制品的品种和应用则与日俱增。     

2010年全球天然橡胶产量增长6.6%

据美国《橡胶世界》报道,天然橡胶生产国协会(ANRPC)报告称,2010年世界天然橡胶总产量比2009年增长6.6%,尽管今年第三季度因天气条件不利于割胶而产量有所下降。ANRPC的所有     

Microstructure, dielectric and piezoelectric properties of lead-free Bi 0·5 Na 0·5 TiO 3 −Bi 0·5 K 0·5 TiO 3 −BiMnO 3 ceramics

To improve the piezoelectric properties of Bi _0·5Na _0·5TiO ₃-based ceramics, a new perovskite-type lead-free piezoelectric (1 –  x –  y)Bi _0·5Na _0·5TiO ₃??xBi _0·5K _0·5TiO ₃??yBiMnO ₃ system has been fabricated by a conventional solid–state reaction method and their microstructure, dielectric and piezoelectric properties have been investigated. The results of X-ray diffraction (XRD) analysis reveal that the addition of small amounts of BiMnO ₃ did not cause a remarkable change in crystal structure, but resulted in an evident evolution in microstructure. An obvious secondary phase was observed in samples with high Bi _0·5K _0·5TiO ₃ content. It is found from dielectric constant curves that low-temperature hump disappeared with increasing y and it appeared again with increasing x. The piezoelectric properties significantly increase with increasing Bi_0·5K_0·5TiO₃ and BiMnO ₃ content. The piezoelectric constant and electromechanical coupling factor attain maximum values of d ₃₃?=?182 pC/N at x = 0·21(y = 0·01) and k _p = 0·333 at x = 0·18 (y = 0·01), respectively.