Properties of pyrolytic chars and activated carbons derived from pilot-scale pyrolysis of used tires.

Used tires were pyrolyzed in a pilot-scale quasi-inert rotary kiln. Influences of variables, such as time, temperature, and agent flow, on the activation of obtained char were subsequently investigated in a laboratory-scale fixed bed. Mesoporous pores are found to be dominant in the pore structures of raw char. Brunauer-Emmett-Teller (BET) surfaces of activated chars increased linearly with carbon burnoff. The carbon burnoff of tire char achieved by carbon dioxide (CO2) under otherwise identical conditions was on average 75% of that achieved by steam, but their BET surfaces are almost the same. The proper activation greatly improved the aqueous adsorption of raw char, especially for small molecular adsorbates, for example, phenol from 6 to 51 mg/g. With increasing burnoff, phenol adsorption exhibited a first-stage linear increase followed by a rapid drop after 30% burnoff. Similarly, iodine adsorption first increased linearly, but it held as the burnoff exceeded 40%, which implied that the reduction of iodine adsorption due to decreasing micropores was partially made up by increasing mesopores. Both raw chars and activated chars showed appreciable adsorption capacity of methylene-blue comparable with that of commercial carbons. Thus, tire-derived activated carbons can be used as an excellent mesoporous adsorbent for larger molecular species.

[Congenital absence of upper anterior teeth a dentofacial morphologic analysis].

OBJECTIVE: This study was designed to examine the dentofacial morphology of the children in Shanghai with congenital absence of upper anterior teeth. METHODS: Cephalometric analysis for 37 children with congenital absence of upper anterior teeth was conducted and was compared with that of the normal ones. RESULTS: (1) There was no significant difference in all measurements between gender. (2) Craniofacial defection included a small SNA a small ANB a small AoBo a small angle of convexity,and a large AB plane angle. Vertical facial dimensions which was shown by Y axis and mandibular plane angle significantly decreased. Examination for soft tissue also revealed a small convexity of soft tissue and a large CmSnUL. (3) A compensative proclination of the upper central incisors as well as the upper lip was also found. CONCLUSION: Patients with congenital absence of upper anterior teeth might have a small maxilla a relatively normal mandibular dimension an anticlock rotation of the mandible plane, and a compensative proclination of the upper central incisors and the upper lip.

[Research on energy metabolism enzyme in liver of the rabbit during hemorrhagic shock and effect of acupuncture at "renzhong" acupoint by quantitative histochemistry].

The energy crisis has been considered to act an important role during shock recent years. We all know the liver can supply for energy substrate when body is in an emergency condition. According to the theory of Traditional Chinese Medicine, Renzhong acupoint is a very important acupoint to treat "Jue Zheng" (including shock). We divided 36 male rabbits into three groups randomly, they were normal, acupuncture and nonacupuncture. The normal control was anesthetized only with sodium pentobarbital (35mg/kg). The acupuncture and nonacupuncture groups were operated under conscious with method of improving Wiggers(1950). After bleeding 20ml/kg, these animals were in shock. Then the acupuncture group was applied with acupuncture at "Renzhong" and the nonacupuncture group was not during hemorrhagic shock. The samples of liver were excised and stained using enzyme histochemical method. All of them were determined with MPV-2 and Univar-SMSP. Two dehydrogenases (LDH and SDH) in hepatocytes were observed in this work. The results showed that the enzyme's activity in nonacupuncture both LDH and SDH were the weakest among three groups (P less than 0.01 and P less than 0.05). But in acupuncture group, they were stronger than nonacupuncture group and near normal control. These suggest that acupuncture at "Renzhong" acupoint can increase activity of LDH and SDH during hemorrhagic shock. It is useful to resistance shock in a certain degree.