Takashi Miyado

Development of a novel running buffer for the simultaneous determination of nitrate and nitrite in human serum by capillary zone electrophoresis.

In order to improve NO2- peak height and obtain a convenient buffer system for the assay of nitrogen monooxide metabolites, we developed a novel running buffer for the simultaneous determination of nitrite and nitrate in human serum by capillary electrophoresis. The addition of cetyltrimethylammonium chloride to the running buffer resulted in high-speed separation using reverse electroosmotic flow. Highly sensitive determination was also achieved using stacking with 10-fold diluted sample solutions. The samples were injected hydrodynamically for 100 s into a 50 cm x 75 microm I.D. capillary. The separation voltage was 10 kV (negative polarity). UV detection was performed at 214 nm. We obtained complete separation of nitrite and nitrate in deproteinized human serum within 6 min with optimum analytical conditions. Linear calibration curves for nitrite and nitrate for both peak height and peak area were obtained with standard addition method. The limits of detection obtained at a signal-to-noise ratio of 3 for nitrite and nitrate were 4.1 and 2.0 microM, while the values of relative standard deviation of peak height were 2.4 and 2.6%, respectively.

Determination of nitrite and nitrate in a proposed certified reference material for nutrients in seawater by capillary zone electrophoresis with artificial seawater as the background electrolyte using transient isotachophoresis

We describe a combination of selected ions as a terminating ion which is useful for transient isotachophoresis (ITP) in capillary zone electrophoresis (CZE) for the determination of nitrite and nitrate in seawater. In addition to 150 mM sulfate as the principal terminating ion, 10 mM bromate was added to a sample solution as the additional terminating ion. Artificial seawater containing 3 mM cetyltrimethylammonium chloride (CTAC) was adopted as a background electrolyte (BGE). The limits of detection (LODs) for nitrite and nitrate were 2.2 and 1.0 νg/L (as nitrogen), respectively. The LODs were obtained at a signal to noise ratio (S/N) of 3. The values of the relative standard deviation (RSD) of peak area for these ions were 1.9 and 1.4%. The RSDs of peak height were 1.7 and 1.9%, the RSDs of migration time 0.11%. The proposed method was applied to the determination of nitrite and nitrate in a proposed certified reference material for nutrients in seawater, MOOS‐1, distributed by the National Research Council of Canada (NRC). The results almost agreed with the assigned tolerance interval.

High-throughput assay of nitric oxide metabolites in human plasma without deproteinization by lab-on-a-chip electrophoresis using a zwitterionic additive

In order to develop a high-throughput assay for nitric oxide metabolites, nitrite (NO2-) and nitrate (NO3-), in biological fluids, we have investigated the simultaneous determination of them using an electrophoretic lab-on-a-chip (microchip capillary electrophoresis, MCE) technique. In this study, in order to establish an MCE assay process without deproteinization, the addition of a zwitterionic additive into the running buffer to reduce the adsorption of protein onto the surface of channel was investigated. Initially, some zwitterionic additives were investigated by making a comparison of relative standard deviations (RSDs) of the migration times for NO2(-) and NO3(-) on capillary electrophoresis. From the results of our comparison of the RSD values, 2% (w/w) N-cyclohexyl-2-aminoethanesulfonic acid (CHES) was selected. As a result of the application of the running buffer with CHES to the MCE process, the complete separation of NO2(-) and NO3(-) in human plasma without deproteinization was achieved within 1 min. Since the RSD values of the positions of the peaks were less than 2.3%, beneficial reduction effects on MCE were suggested. When we used an internal standard method in order to correct the injection volume, the RSDs of the peak heights and areas were less than 10%, and the correlation coefficients of spiked calibration curves ranging from 0 to 350 microM were 0.999 and 0.997 for NO2(-) and NO3(-), respectively. The limits of detection (S/N=3) were 53 microM for NO2(-) and 41 microM for NO3(-). Moreover, the correlation coefficients in excess of 0.99 between the MCE method and a conventional Griess method were achieved for both NO2(-) and NO3(-). Consequently, the possibility of establishing a high-throughput assay process was obtained by utilizing 2% (w/w) CHES to reduce protein adsorption.

Toward evaluation of a ship navigator's stress based on salivary amylase activity

Evaluation of ship handling training has usually depended on professionals who have a lot of experience on board. We are attempting to evaluate a ship navigators mental workload (stress) based on a physiological index. The physiological indices, heart rate variability and nasal temperature, are good indices of the stress found in ship handling; however, it is best if we get response and evaluation results quickly on the spot. A recent study shows salivary amylase activity is reflected by the sympathetic nervous system. This paper proposes that salivary amylase activity shows a ship navigators stress during ship handling.

Evaluation of ship navigator's mental workload for ship handling based on salivary NO 3 −

The Evaluation of mental workload/ performance has usually depended on professionals (captain, pilot) who have a lot of experience on board. We are attempting to evaluate a ship navigators mental workload based on a physiological index. The physiological indices, heart rate variability (R-R interval), nasal temperature, and salivary amylase, are good indices for reading the mental workload in ship handling. Moreover, we have found a possibility of salivary NO3- as a good index for evaluating the navigators mental workload. The salivary NO3- is expected to have a specific characteristic to represent quick response on the spot and the trend like moving average. We confirmed the response of students for simulator training, and we were carried out the experiment for professionals on a real ship. This paper proposes that salivary NO3- shows a ship navigators mental workload for ship handling in the simulator and a real ship. This research, to evaluate the mental workload of navigators using salivary NO3-, is first challenge worldwide.

Measurement of a Navigator's Mental Workload for Ship Handling Based on Saliva Nitric Oxide Assay

We ultimately propose that salivary NO₃^- shows mental workload of ship navigators, and confirm that new navigators can find out and avoid the situations where veteran navigators accumulate mental workload by using salivary NO₃^- measurement device. There are various physiological indices in the world, for example heart rate variability (R-R interval), nasal temperature, and salivary amylase, these are exactly good indices but cannot represent quick response on the spot and the trend like a moving average as well as salivary NO₃^-. We must create the salivary NO₃^- measurement device because this research, to evaluate the mental workload of navigators using salivary NO₃^-, is first challenge worldwide. We confirmed the response of students for simulator based training, and we were carried out the experiment for professionals on a real ship. So this paper proposes that we evaluate salivary NO₃^- in a daily life, for example, for smoking, eating, car driving, and exercising, and then that salivary NO₃^- shows a navigators mental workload for ship handling in the simulator and a real ship.

Study on ship navigators' mental workload for ship handling based on salivary NO 3 −

The evaluation of mental workload/ performance has usually depended on professionals (captain, pilot) who have a lot of experience on board. We are mainly attempting to evaluate a ship navigators mental workload based on a physiological index. The physiological indices, heart rate variability (R-R interval), nasal temperature, and salivary amylase, sharply respond to events of ship handling. Moreover, we have found a possibility of salivary NO3- as a good index for evaluating the mental workload. The salivary NO3- is expected to have a specific characteristic to represent a quick response on the spot and the trend like moving average. We confirmed the response of students for simulator based training, and we were carried out the experiment for professionals on a real ship. This paper proposes that salivary NO3- shows a navigators mental workload for ship handling in a ship handling simulator (simulator), and it is compared with heart rate variability. This research, to evaluate the mental workload of navigators using salivary NO3-, is first challenge worldwide.