Research of Polyocarboxy Acid Water-Reducer with Modified Ployether and its Effect on Concrete’s Workability

In this paper, polycarboxylic type high performance water reducers have been synthesized through using TPEG modified monomer. If synthetic temperature and addition time of copolymer monomers can be controlled, the performance of polycarboxylic superplasticizer will be improved. Testing results indicates that when temperature is at 60~65°C, addition time of copolymer monomers is three hours, the performance of superplasticizer is best. Through High Performance Liquid Chroma- tography (HPLC) testing, we can find it is almost the same with the famous brand abroad of the same type. The ues of polycarboxylic type high performance water reducers cooperated with naphthalene series high range water reducing agents thereby markedly improv the workability of concrete mixture.

Effects of parasitism on the octopamine content of the central nervous system of Manduca sexta: a possible mechanism underlying host behavioural change

The parasitic wasp Cotesia congregata lays its eggs inside the larva of Manduca sexta (tobacco hornworm). Beginning about 12 h before the wasp larvae emerge from the host, host feeding and locomotion decline. The octopamine content of the central nervous system (CNS) of parasitized hosts was measured using high-performance liquid chroma tography with electrochemical detection. Concomitant with the decrease in host feeding and locomotion, the octopamine content of the host's brain (supra- and sub-esophageal ganglia), thoracic ganglia, and abdominal ganglia increased. In nonparasitized M. sexta, the octopamine content of the CNS did not change significantly during moult sleep, a stage in which the behaviour superficially resembles that of M. sexta after the wasps have emerged. Neither result is consistent with the hypothesis that the octopamine content within the CNS is lower in inactive insects. Nevertheless, the close temporal correlation between the change in host behaviour and CNS octopamine content suggests that alterations in the functioning of the octopaminergic system may play a role in depressing host feeding and (or) locomotion.

High Performance Liquid Chroma tographic Analysis of Dicofol Acaricide

Kelthane Technical, a dicofol acaricide marketed by Rohm and Haas Co., and 18 impurity components can be resolved by a new reverse phase high performance liquid chromatographic (HPLC) method using a methanol-water-acetic acid (75+25+0.2) mobile phase, a high resolution C8 column in series with a short Cl8 s guard column, and detection at 254 nm. Relative elution volumes: and relative sensitivities for all known Kelthane Technical components are reported. This HPLC method has few co-elution problems, can be performed on a basic HPLC system, avoids the thermal degradation of Kelthane experienced in the previously established gas-liquid chromatographic (GLC) procedures, and can detect all impurity components to at least 0.1% level.