Publications by authors named "Yasuo Takayama"

Article Synopsis
  • The study focuses on detecting the ion Ph2As(+) to monitor harmful chemical agents (DA and DC) in the air using a specific mass spectrometry technique.
  • A liquid sample containing these agents was heated to generate vapor, which was then mixed with humidified air for analysis.
  • Results showed that as humidity increased, the Ph2As(+) signal became stronger, indicating that the monitored compounds were converting to BDPAO, which is a source of Ph2As(+).
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A new method enabling sensitive real-time air monitoring of highly reactive chemical warfare agents, namely, mustard gas (HD) and Lewisite 1 (L1), by detecting ions of their in-line reaction products instead of intact agents, is proposed. The method is based on corona discharge-initiated atmospheric pressure chemical ionization coupled with ion trap tandem mass spectrometry (MS(n)) via counterflow ion introduction. Therefore, it allows for highly sensitive and specific real-time detection of a broad range of airborne compounds.

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A highly sensitive and specific real-time field-deployable detection technology, based on counterflow air introduction atmospheric pressure chemical ionization, has been developed for a wide range of chemical warfare agents (CWAs) comprising gaseous (two blood agents, three choking agents), volatile (six nerve gases and one precursor agent, five blister agents), and nonvolatile (three lachrymators, three vomiting agents) agents in air. The approach can afford effective chemical ionization, in both positive and negative ion modes, for ion trap multiple-stage mass spectrometry (MS(n)). The volatile and nonvolatile CWAs tested provided characteristic ions, which were fragmented into MS(3) product ions in positive and negative ion modes.

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A new method for sensitively and selectively detecting chemical warfare agents (CWAs) in air was developed using counter-flow introduction atmospheric pressure chemical ionization mass spectrometry (MS). Four volatile and highly toxic CWAs were examined, including the nerve gases sarin and tabun, and the blister agents mustard gas (HD) and Lewisite 1 (L1). Soft ionization was performed using corona discharge to form reactant ions, and the ions were sent in the direction opposite to the airflow by an electric field to eliminate the interfering neutral molecules such as ozone and nitrogen oxide.

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A 29-year-old man developed diabetes mellitus in 1983 and diabetic nephropathy which gradually worsened from 1998. He was admitted to our hospital for initiation of peritoneal dialysis in May 2002. However, the efficiency of dialysis was not sufficient to improve elevated levels of blood urea nitrogen and serum creatinine.

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Article Synopsis
  • Clinical studies show nonischemic dysfunction can occur in areas adjacent to ischemic heart tissue, highlighting the complexity of heart damage during ischemic events.* -
  • An investigation involving dogs found that administering an AT1-receptor antagonist after reperfusion reduced heart injury, as evidenced by a smaller infarct size compared to control dogs.* -
  • The reduction in infarct size did not correlate with changes in the heart function of nearby tissue, suggesting that the antagonist works primarily by affecting overall heart damage rather than immediate adjacent tissue function.*
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The ventricular myocardium consists of a syncytium of myocytes organized into branching, transmurally oriented laminar sheets approximately four cells thick. When systolic deformation is expressed in an axis system determined by the anatomy of the laminar architecture, laminar sheets of myocytes shear and laterally extend in an approximately radial direction. These deformations account for ~90% of normal systolic wall thickening in the left ventricular free wall.

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