A compact tritium enrichment unit for large sample volumes with automated re-filling and higher enrichment factor.

Tritium (3H) in natural waters is a powerful tracer of hydrological processes, but its low concentrations require electrolytic enrichment before precise measurements can be made with a liquid scintillation counter. Here, we describe a newly developed, compact tritium enrichment unit which can be used to enrich up to 2L of a water sample. This allows a high enrichment factor (>100) for measuring low 3H contents of <0.05TU. The TEU uses a small cell (250mL) with automated re-filling and a CO2 bubbling technique to neutralize the high alkalinity of enriched samples. The enriched residual sample is retrieved from the cell under vacuum by cryogenic distillation at -20°C and the tritium enrichment factor for each sample is accurately determined by measuring pre- and post- enrichment 2H concentrations with laser spectrometry.

Genetic characterization of Toxoplasma gondii from domestic animals in central China.

Toxoplasma gondii is an obligate intracellular parasite that has a remarkable ability to infect almost all warm-blooded animals, including humans. This study was aimed to determine the genetic characteristics of T. gondii isolates from domestic animals in Henan Province, central China. A total of 363 DNA samples, including 208 from hilar lymph nodes of pigs, 36 from blood samples of cats, 12 from tissues of aborted bovine fetuses and 107 from blood samples of dams with history of abortion in Henan Province, were examined for the presence of T. gondii by nested PCR based on B1 gene. The positive DNA samples were further genotyped by PCR-RFLP at 11 markers, including SAG1, (3'+ 5') SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico. DNA samples from 9 pigs, 5 cats, and 4 dairy cows were T. gondii B1 gene positive. Nine samples were successfully genotyped at all genetic loci, of which 5 samples from pigs, and 2 from cats were identified as ToxoDB genotype #9, and 2 samples from cows belonged to ToxoDB genotype #225. To our knowledge, the present study is the second report of genetic typing of T. gondii isolates from cattle in China, and the first report of T. gondii ToxoDB#225 from cattle.

Genetic characterization of Toxoplasma gondii from domestic animals in central China

Toxoplasma gondii is an obligate intracellular parasite that has a remarkable ability to infect almost all warm-blooded animals, including humans. This study was aimed to determine the genetic characteristics of T. gondii isolates from domestic animals in Henan Province, central China. A total of 363 DNA samples, including 208 from hilar lymph nodes of pigs, 36 from blood samples of cats, 12 from tissues of aborted bovine fetuses and 107 from blood samples of dams with history of abortion in Henan Province, were examined for the presence of T. gondii by nested PCR based on B1 gene. The positive DNA samples were further genotyped by PCR-RFLP at 11 markers, including SAG1, (3’+ 5’) SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico. DNA samples from 9 pigs, 5 cats, and 4 dairy cows were T. gondii B1 gene positive. Nine samples were successfully genotyped at all genetic loci, of which 5 samples from pigs, and 2 from cats were identified as ToxoDB genotype #9, and 2 samples from cows belonged to ToxoDB genotype #225. To our knowledge, the present study is the second report of genetic typing of T. gondii isolates from cattle in China, and the first report of T. gondii ToxoDB#225 from cattle.

Reversed-phase liquid chromatography of alkaloids: Masking effects of inorganic salts.

The addition of salts (investigated cations Na(+), NH(+)(4), K(+), KBu(+)(4) combined with the anions acetate, Br(-), SCN(-) and I(-)) can be used to eliminate peak tailing and to decrease retention of cationic species in the course of the separation of alkaloids from Chelidonium majus L. by reversed-phase chromatography on a ODS Hypersil column, using water-acetonitrile-methanol mixture as eluent. These findings are interpreted in terms of a silanol masking effect. The extended donor-acceptor concept is used to interpret the effectiveness of different salts in masking the active sites of the stationary phase.

Microwave radiation and heart-beat rate of rabbits.

Each of three adult New Zealand rabbits, 2 male and 1 female albinos, was exposed dorsally or ventrally, to 2450-MHz plane waves for 20 min under each of several field conditions: 1) to continuous waves (CW) at 5 mW/cm2; 2) to pulsed waves (PW) of 1-microsecond width that recurred 700 pps at an average of 5 mW/cm2 and at a peak of 7.1 W/cm2; 3) to PW of 10-microseconds width at a peak of 13.7 W/cm2 that were synchronized with and triggered by the R wave of the electrocardiogram (EKG) at various delay times (0, 100, and 200 ms; and 4) to CW at 80 mW/cm2. Carbon-loaded Teflon electrodes were used to record the EKG from forelimbs of an animal before, during, and after irradiation whilst it was maintained in a constant exposure geometry in a wooden squeeze box. Field induced changes in the heart-beat rate were observed at 80 mW/cm2 but not a lower average power densities, although a peak positive chronotropic effect might have been occasioned by PM introduced at 100 and 200 ms after the R wave peak. No cumulative effect was observed over a period of four months. Thermographic analysis revealed relatively little absorption of microwave energy by the myocardium irrespective of anatomical aspect of exposure.