Determination of inorganic tin in biological samples by hydride generation-atomic absorption spectrometry after silica gel cleanup

A method is described for the determination of inorganic tin in biological samples by hydride generation-atomic absorption spectrometry (HG-AAS). A sample is extracted with ethyl acetate after addition of HCl and NaCl. The concentrated extract is passed through a silica gel column. The column is washed with ethanol, water, and 0.2N HCl successively, and then inorganic tin is eluted with 2N HCl and measured by HG-AAS. Recoveries from fish muscle spiked with 0.1 micrograms/g Sn4+ are 78.9 +/- 4.2% (average +/- standard deviation, n = 5). The detection limit is 0.01 micrograms/g as Sn.     

Behaviors of D- and L-lactic acids during the brewing process of sake (Japanese rice wine)

The amounts of D- and L-lactic acids during the brewing process of sake were determined by capillary electrophoresis using 2-hydroxypropyl-beta-cyclodextrin as a chiral selector. Because L-lactic acid, which prevents the growth of nonuseful microorganisms, is a raw material of sake, the ratio of L-lactic acid to total lactic acid is almost 1.0 at the initial stage of sake brewing. During brewing, the ratio decreased gradually and finally reached 0.39. Yeast (Saccharomyces cerevisiae) for sake brewing produced D-lactic acid, but not L-lactic acid in a culture medium. These results suggest that the decrease in the ratio of L-lactic acid to total lactic acid during sake brewing resulted in D-lactic acid production by yeast. The ratios in 18 brands of sake obtained commercially ranged from 0.23 to 0.78. The levels of D-lactic acid in sake (140-274 mg/L) were in a narrower range than those of L-lactic acid (61-461 mg/L). Although the D-lactic acid level in sake did not correspond to total lactic acid level, the L-lactic acid level correlated well with total lactic acid level (R(2) = 0.867). These results suggest that the ratio of L-lactic acid to total lactic acid in sake reflected the amount of L-lactic acid added at the initial stage of sake brewing.     

Dating of a fault by electron spin resonance on intrafault materials

The total dose of natural radiation and the age were determined from paramagnetic defects in quartz grains at a fractured fault zone. Young age at the fault indicates that the accumulated defects in rocks were destroyed by high stress or high temperature at the time of the last fault movement, setting the clock time to zero. The technique was applied to quartz grains crushed by uniaxial compression in the laboratory to verify this interpretation.     

Cloning, sequencing, and expression of the gene coding for the human platelet alpha 2-adrenergic receptor

The gene for the human platelet alpha 2-adrenergic receptor has been cloned with oligonucleotides corresponding to the partial amino acid sequence of the purified receptor. The identity of this gene has been confirmed by the binding of alpha 2-adrenergic ligands to the cloned receptor expressed in Xenopus laevis oocytes. The deduced amino acid sequence is most similar to the recently cloned human beta 2- and beta 1-adrenergic receptors; however, similarities to the muscarinic cholinergic receptors are also evident. Two related genes have been identified by low stringency Southern blot analysis. These genes may represent additional alpha 2-adrenergic receptor subtypes.     

Characterization of a Phytophthora mating hormone

Water molds of the genus Phytophthora include many plant pathogens responsible for epidemics such as potato blight and sudden oak death, causing global economic damages. Sexual reproduction is of biological importance in Phytophthora and has been believed to be stimulated by unknown endogenous factors named a hormones. We describe here the chemical characterization of a Phytophthora mating hormone, a1, which was obtained from approximately 2 tons of culture fluid of one mating type of a species and which induced sexual spores on the counter-mating type at a nanogram level.     

Protective role of ATP-sensitive potassium channels in hypoxia-induced generalized seizure

Adenosine triphosphate (ATP)-sensitive potassium (K(ATP)) channels are activated by various metabolic stresses, including hypoxia. The substantia nigra pars reticulata (SNr), the area with the highest expression of K(ATP) channels in the brain, plays a pivotal role in the control of seizures. Mutant mice lacking the Kir6.2 subunit of K(ATP) channels [knockout (KO) mice] were susceptible to generalized seizures after brief hypoxia. In normal mice, SNr neuron activity was inactivated during hypoxia by the opening of the postsynaptic K(ATP) channels, whereas in KO mice, the activity of these neurons was enhanced. K(ATP) channels exert a depressant effect on SNr neuronal activity during hypoxia and may be involved in the nigral protection mechanism against generalized seizures.     

Prospects for multifunctionality of paddy rice cultivation in Japan and other countries in monsoon Asia

This paper presents a study carried out by a group of Japanese researchers to critically review past researches and discussions on the multifunctionality of paddy rice cultivation, with the aim of describing the current status of the subject and providing options and potentials for future research and practices. The review was of over 200 documented articles on the major external functions. The results of this study revealed that the importance of multifunctionality is well perceived in Japan. The methodologies to measure and estimate the magnitude have been established for most functions. However, there is a need for more cases, to integrate all the functions at the local or regional scale to represent site-specific characteristics of multifunctionality. There is also a need to develop management practices to sustain and enhance the positive multifunctionality of paddy rice cultivation while minimizing negative effects to the environment, which may be brought into the agricultural policies. Except for Korea, Taiwan, and Japan, there are slightly different notions on multifunctionality in other monsoon Asia countries, but the gap in this notion is reducing following recent international activities.     

Seasonal and Annual Fluxes of Inorganic Constituents in a Small Catchment of a Japanese Cedar Forest near the Sea of Japan

Fluxes of major ions in rainfall (RF), throughfall plus stemflow (TF + SF), and stream water (SW) were measured for five water years in a small catchment of a Japanese cedar forest near the Sea of Japan. The fluxes of most ions in RF and in TF + SF, including the non-sea-salt constituents, increased from late autumn to midwinter owing to the seasonal westerly wind. The concentrations of most ions in SW showed no obvious seasonal trend during the study period, whereas ${\text{NO}}_3 ^ - $ concentrations were lowest in summer, with a small seasonality. The Ca²⁺ and Mg²⁺ outputs in SW were approximately 3.7 and 1.8 times the TF + SF inputs of these cations, respectively. The large net outputs of base cations in the catchment may indicate a decrease in the soil's acid-neutralizing capacity. Annual dissolved inorganic nitrogen inputs in RF and in TF + SF were 17.7 and 17.9 kg N ha^?1 year^?1, respectively, which exceeded previously published thresholds in Europe and the U.S. (i.e., the values at which these inputs increased ${\text{NO}}_3 ^ - $ levels in SW) and equaled the highest level of nitrogen deposition previously reported in Japan. The ${\text{NO}}_{\text{3}} ^{\text{ - }} $ concentrations in SW were relatively high even in summer. During high-precipitation events, ${\text{NO}}_{\text{3}} ^{\text{ - }} $ concentrations in SW increased with increasing water discharge, and the pH decreased simultaneously during several events. Nitrogen deposition may contribute to the high ${\text{NO}}_{\text{3}} ^{\text{ - }} $ concentrations in SW and the temporary acidification that occurred during the rain events.     

Effects of climate change on reduction of internal bond strength of particleboard subjected to various climatic conditions in Japan

The effects of climate change on the reduction of internal bond strength (IB) of particleboard subjected to various climatic conditions in Japan were predicted. The temperature increased throughout Japan with increasing greenhouse gas (GHG) emissions, so the climate deterioration index (climate index for predicting the IB reduction of particleboard; a high index indicates a large IB reduction) also increased to decrease IB. The number of low-temperature areas decreased because of climate change. The rupture of bonding points in particleboard caused by outdoor exposure led to a IB reduction, and biodeterioration accelerated this reduction. In high-temperature areas, particleboard was found to be prone to biodeterioration, and the IB significantly reduced. An area wherein there was a significant decrease in the IB spread along the Pacific Ocean side of western Japan and the Sea of Japan in central Japan in relation to increasing GHG emissions. Particleboards are difficult to use outdoors because of climate change.