Noriaki Kaneki

Measurement of pork freshness using potentiometric sensor

This study evaluated pork freshness using potentiometric solid-state electrodes in order to detect chemical indices such as reduced compounds, organic compounds and sulfides, which are produced during the initial stage of putrefaction in meat. Pt, CuS and Ag(2)S electrodes selected as solid-state electrodes have, respectively, been used to detect the organic compounds (regarded as chemical indices of deterioration in meat freshness). The outputs of these electrodes have been analyzed by principal component analysis (PCA) and multiple regression analysis (MRA) in order to find the correlation with the results of viable bacterial counts. By using the potentiometric sensor, the pork freshness was evaluated and the PCA and MRA corresponded to the degree of bacterial increases more simply and rapidly than other methods such as viable bacterial counts or a biosensor.

Availability and development of an enzyme immunomicrosensor based on an ISFET for human immunoglobulins

Abstract A critical evaluation of the potentiometric response of an enzyme immuno-ISFET sensor has demonstrated that it is an effective, simple sensor for human immunoglobulin (IgG). The sensor was constructed using an immobilized human IgG membrane and an ISFET. The assay procedure involves the competitive immunochemical reaction of ureuse-labelled anti-human IgG with human IgG in samples and membrane-bound IgG and the electrochemical determination of membrane-bound urease activity. A linear relationship was obtained between the initial rate of response and the logarithm of IgG concentration from 0.1 to 2.0 mg ml−1.

Development of a Novel Two Dimensional Surface Plasmon Resonance Sensor Using Multiplied Beam Splitting Optics

A novel two dimensional surface plasmon resonance (SPR) sensor system with a multi-point sensing region is described. The use of multiplied beam splitting optics, as a core technology, permitted multi-point sensing to be achieved. This system was capable of simultaneously measuring nine sensing points. Calibration curves for sucrose obtained on nine sensing points were linear in the range of 0–10% with a correlation factor of 0.996–0.998 with a relative standard deviation of 0.090–4.0%. The detection limits defined as S/N = 3 were 1.98 × 10−6–3.91 × 10−5 RIU. This sensitivity is comparable to that of conventional SPR sensors.

Effect of Odorant Presentation on Changes in Cognitive Interference and Brain Activity during Counting Stroop Task

Cognitive task for longer duration increases subjects psychological loadings because of extracting ordered answer from visual stimuli. The present study investigated how intermittent odorant presentation during cognitive task contributes to cognitive function and statement of psychological loadings. We asked ten male subjects to perform counting stroop task that repeatedly counts the pieces of digits displayed on a monitor. The task consisted three tasks that the digits and the number were consisted (task1), non-consisted (task2), and both the former tasks combined (task3). The duration of each task was four minutes, and thus subjects totally performed the tasks for 12 minutes. Four kinds of odorant stimuli (non-odor, lemon, peppermint (pmint), and skatole (ska)) were used in this study and each odor was presented after beginning of each task for one minute. Behavioral results, rate of content of ƒ¿, ƒÀ, ƒÂ, and ƒÆ waves from EEG, and oxygenated hemoglobin concentration (ƒ¢O2Hb) were measured and compared between each odor condition. Behavioral results, the reaction time and the percentage of questions answered correctly, ƒ¢O2Hb in right hemisphere related to pleasant emotion, and rate of content of ƒ¿ wave were significantly increased when pmint and ska were presented. The findings indicated that intermittent odor presentation induced pleasant emotion and increased cognitive function and state of concentration, regardless of odors.

Development of a portable surface plasmon resonance sensor with multi-sensing points based on the linear CCD sensor

A portable-type surface plasmon resonance (SPR) sensor, composed from a new optical system for multi-sensing, has been developed to apply to environment analysis, clinical diagnosis etc., where many samples are desired to be analyzed at high throughput. The optical system of the sensor consists of a light-emitting diode, a pair of cylindrical lenses, a pair of collimator lenses, a correction lens, a prism, a polarizer and a linear CCD sensor with 2048 pixels. Reflected light from a sensor chip of the width of 6 mm at a certain incident angle was detected by ca. 618 pixels of the linear CCD sensor as an SPR sensor signal. An SPR sensor signal at a specified incident angle is controllable for optimization by adjusting the position of the CCD sensor. A sensor chip having a 30-stripe linear pattern (100 μm width/stripe) was prepared. The spatial resolution as well as the performance of the sensor were evaluated by using sucrose solutions. As a result, the acquisition of SPR sensor signals from 30 sensing points was successfully achieved with a spatial resolution of 100 μm (distance between 2 sensing points). A lower detection limit of ca. 3.2 - 5.5 × 10(-5) RIU with a standard deviation of ±4.5% was obtained by averaging the signals from 6 - 7 pixels of the CCD sensor per one sensing stripe.

Effect of Different Flavors on Physiological and Psychological Responses after Soup Intake with Nutritional Equivalence

This research examined the effect of two soups with equivalent nutritional values but with different flavors on measures of palatability and physiological responses (the frontal cortex blood flow and the respiratory cardiovascular system). A significant difference in palatability between the two soups was confirmed through sensory evaluation. In terms of the physiological responses, significant differences between the two soups were observed in the oxygenated hemoglobin at the right side of the frontal cortex, the heart rate, and the respiratory quotient after soup intake. In particular, the intake of the soup with low palatability caused a rise in oxygenated hemoglobin at the right side of the frontal cortex, followed by a sustained rise in the heart rate in the cardiovascular system and a reduction in the respiratory quotient, all of which, we believe, were stress responses.

Intermittent Presentation of Hinoki Odor as the Inhibitory Factor on the Performance and Physiological Responses in Stroop Task

This experiment examines how intermittent presentation of olfactory stimulus affects performance and physiological responses on performing Stroop task. Eight participants performs word-color Stroop task while Hinoki or no odors are presented for 10 sec in every 45 second. Results show Hinoki, compared with no odor, reduce the performances as indicated in longer correct response time and a larger number of error responses. Hinoki activates left forehead cortical activity as measuren in more OxyHb, and sympathetic nervous function shown in decreased plethysmograpy amplitude and increased alpha amylase. These results indicate intermittent presentation activates attentional process, raises arousal level. The differential results of more and less Hinoki favorite groups of participants indicates less favorite participants are diverted their attention to Hinoki and disturbed to performe the task.

The pleasant odor reduces the brain activity and enhances behavioral performance during kanji word-color stroop task: A multi-fiber NIRS study

The purpose of this study was to investigate that the effect of sensed pleasant odor on the increased psychological loading and brain activity due to the confliction and intervention by the difference between meaning of kanji words and word color. During word-color stroop task, brain activity was estimated by oxy-hemoglobin concentration (ΔO2Hb) and psychological loadings, i.e., status of the autonomic activity, was measured by ECG signal and peripheral blood flow. As a result, when the lavender aroma sensed, ΔO2Hb was decreased and mean response time was significantly shortened as compared with non-odor. The results indicate that the pleasant emotion evoked by the pleasant odor and further the calling effect by lavender aroma inhibited the over activity due to stoop task, and thus facilitate precise reading of the logographical kanji word and word color.

The performance and physical responses during an attention shift task with grapefruit and skatole odor presentation

Performance and physiological responses within performing an attention shift task were compared between grapefruit odor, skatole, odorless air presentation. Ten male students participated in this experiment. They performed 15 min digit detection task three times, that required quick attention shift. During the task, 1 min odor was presented three times. Near infrared spectroscopy and EEG were monitored through the experiment, and offered physiological indexes of oxy-Hb, deoxy-Hb and beta wave component. The number of correct responses and reaction time were better in both grapefruit and skatole presentation than in odorless air. Increased oxy-Hb that indicates activated brain function, was observed only in grapefruit presentation at left forehead. Increased beta wave component that reflects relaxation, was found in grapefruit presentation at F4 (left middle forehead), while decreased beta in skatoke presentation. These findings suggest grapefruit acts as an activator, while skatole as a sedative.

A fluidized bed hydrogen electrode of fuel cell using a hydrogen storage alloy.

アルカリ型水素-酸素燃料電池の水素極についての研究を流動層で行なった。装置はアクリル樹脂製で直径 2.5cm, 高さ 30cm の円筒状であり, 装置内には集電体として装置と同心円の直径 1.5cm, 高さ 5cm のニッケル網が設置されている。操作は装置内に電解液と粒状触媒を入れ, 装置下方から水素ガスを吹き込むことによって触媒を流動させるきわめて簡単な装置である。本報文では, 本装置における操作条件である触媒の粒径, 触媒量および水素ガス空塔速度を検討し, 最良の電極特性が得られる条件を写真観察から決定した。その条件は流動層底部から 5cm 以内の高さで集電体内部に激しい渦状の流動状態が形成されるときに得られる。渦状流れの実現にに触媒粒径, 触媒量および水素ガス空塔速度をそれぞれ選択する必要があった。さらに, 流動層電極の触媒として, 8種の水素吸蔵合金について検討した結果, CaNi5 が触媒としてもっとも優れていた。水素吸蔵合金はオートクレープ中で水素ガスにより吸脱蔵を操作をくり返し, 活性化する必要があるが, CaNi5 は活性化を施さないで触媒としての特性が得られ, そのため実験操作が簡略化された。