Yoshihiro Shimomura

Water-filled laparoendoscopic surgery (WAFLES): feasibility study in porcine model.

PURPOSE Recent surgical techniques have been advancing under endoscopic view and insufflation of carbon dioxide gas to expand the abdominal cavity. Isotonic fluid could be one candidate for expanding cavities to facilitate surgical maneuvering. We tested the feasibility and drawbacks of replacement of irrigating materials using a porcine model (water-filled laparoendoscopic surgery [WAFLES]). MATERIALS AND METHODS Laparoscopic cholecystectomy was performed in two porcine models using instillation of sorbitol solution as irrigant. Solution irrigation was performed through one of four ports, with drainage via another port. Conventional forceps equipped with a monopolar electrode for electrocautery, laparoscope, video processor, ultrasound, and transducer for measuring intraabdominal pressure were used. RESULTS Laparoscopic cholecystectomy was successfully undertaken with the following benefits: (1) clear observation of the dissecting plane throughout maneuvering; (2) control of oozing and spilled bile by irrigation and suction; and (3) ultrasonographic and laparoscopic images can be obtained simultaneously without any restriction to probe location. However, two disadvantages should be noted: (1) difficulties in managing floating organs and (2) interruption of vision by blood. CONCLUSIONS WAFLES provides some benefits for endoscopic surgery with proper devices, including apparatuses for irrigation and suction. Efficient irrigation and selection of proper irrigant and apparatuses are required to establish an acceptable procedure.

Effects of blue pulsed light on human physiological functions and subjective evaluation

BackgroundIt has been assumed that light with a higher irradiance of pulsed blue light has a much greater influence than that of light with a lower irradiance of steady blue light, although they have the same multiplication value of irradiance and duration. We examined the non-visual physiological effects of blue pulsed light, and determined whether it is sensed visually as being blue.FindingsSeven young male volunteers participated in the study. We placed a circular screen (diameter 500 mm) in front of the participants and irradiated it using blue and/or white light-emitting diodes (LEDs), and we used halogen lamps as a standard illuminant. We applied three steady light conditions of white LED (F0), blue LED + white LED (F10), and blue LED (F100), and a blue pulsed light condition of a 100-μs pulse width with a 10% duty ratio (P10). The irradiance of all four conditions at the participants eye level was almost the same, at around 12 μW/cm2. We measured their pupil diameter, recorded electroencephalogram readings and Kwansei Gakuin Sleepiness Scale score, and collected subjective evaluations. The subjective bluish score under the F100 condition was significantly higher than those under other conditions. Even under the P10 condition with a 10% duty ratio of blue pulsed light and the F10 condition, the participant did not perceive the light as bluish. Pupillary light response under the P10 pulsed light condition was significantly greater than under the F10 condition, even though the two conditions had equal blue light components.ConclusionsThe pupil constricted under the blue pulsed light condition, indicating a non-visual effect of the lighting, even though the participants did not perceive the light as bluish.

Physiological functions of the effects of the different bathing method on recovery from local muscle fatigue

BackgroundRecently, mist saunas have been used in the home as a new bathing style in Japan. However, there are still few reports on the effects of bathing methods on recovery from muscle fatigue. Furthermore, the effect of mist sauna bathing on human physiological function has not yet been revealed. Therefore, we measured the physiological effects of bathing methods including the mist sauna on recovery from muscle fatigue.MethodsThe bathing methods studied included four conditions: full immersion bath, shower, mist sauna, and no bathing as a control. Ten men participated in this study. The participants completed four consecutive sessions: a 30-min rest period, a 10-min all out elbow flexion task period, a 10-min bathing period, and a 10-min recovery period. We evaluated the mean power frequency (MNF) of the electromyogram (EMG), rectal temperature (Tre), skin temperature (Tsk), skin blood flow (SBF), concentration of oxygenated hemoglobin (O2Hb), and subjective evaluation.ResultsWe found that the MNF under the full immersion bath condition was significantly higher than those under the other conditions. Furthermore, Tre, SBF, and O2Hb under the full immersion bath condition were significantly higher than under the other conditions.ConclusionsFollowing the results for the full immersion bath condition, the SBF and O2Hb of the mist sauna condition were significantly higher than those for the shower and no bathing conditions. These results suggest that full immersion bath and mist sauna are effective in facilitating recovery from muscle fatigue.

Effects of a vertical console position on operator muscular stress during ultrasonic diagnosis

Ultrasound examinations tend to put sonographers in unnatural postures, which may lead to musculoskeletal disorders. In this study, we focused on the height of the operation panel of the diagnostic ultrasound system to quantitatively assess the effects of panel height (work plane height) on musculoskeletal stress during scanning in a sitting position. Eight subjects were asked to perform a simulated scanning task that involved touching nine points on the operation panel at four different panel heights. Electromyogram, left wrist joint angle, and subjective evaluation on ease of manipulation, etc., indicated that the optimum height of the operation panel during scanning in a sitting position is elbow height.

Effects of strap support in a hand-held device on the muscular activity in female workers assessed by electromyography and subjective rating

The present study evaluates the potential mitigation of physical workload when using strap support for a portable device. The experiments were designed as consecutive sessions over a 2-h period. Electromyogram signals were recorded from four muscles of six subjects. The perceived level of fatigue on the whole body as well as in the shoulder, arm, lower back and legs was assessed using Borgs CR-10 scale. All subjects were tested under eight experimental conditions. Results indicated that the biceps brachii muscle displayed significantly lower activity with strap support than without a strap. In the experiments with and without a strap, different levels of force were imposed on the various muscles, which caused changes in the distribution of the physical load. Although the role of the strap might seem evident, using strap support did not always decrease the sensation of fatigue. However, for short-term tasks, using a strap may be recommended.

Sustaining biological welfare for our future through consistent science

Physiological anthropology presently covers a very broad range of human knowledge and engineering technologies. This study reviews scientific inconsistencies within a variety of areas: sitting posture; negative air ions; oxygen inhalation; alpha brain waves induced by music and ultrasound; 1/f fluctuations; the evaluation of feelings using surface electroencephalography; Kansei; universal design; and anti-stress issues. We found that the inconsistencies within these areas indicate the importance of integrative thinking and the need to maintain the perspective on the biological benefit to humanity. Analytical science divides human physiological functions into discrete details, although individuals comprise a unified collection of whole-body functions. Such disparate considerations contribute to the misunderstanding of physiological functions and the misevaluation of positive and negative values for humankind. Research related to human health will, in future, depend on the concept of maintaining physiological functions based on consistent science and on sustaining human health to maintain biological welfare in future generations.

Effect of simultaneous exposure to extremely short pulses of blue and green light on human pupillary constriction

Background Light has various influences on all species, including humans. In natural environments, the only light source is sunlight. Humans have been evolving and adapting under such natural light environments. In modern society, illumination in the workplace has a great influence on work efficiency and the health of workers [1]. The effects of illumination are classified as visual effects and non-visual or non-image-forming (NIF) effects. Recently, a number of studies in the field of physiological anthropology have focused on the NIF effects of illumination on humans [2–8]. In 2002, melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs), a novel type of photoreceptor cells, were found in the mammalian retina [9, 10]. It was confirmed that ipRGCs respond to shortwavelength (blue) light of around 480 nm [9, 11, 12]. The ipRGCs in the retina of the eye affect the interlamellar nuclei of the lateral geniculate nucleus, suprachiasmatic nucleus, intergeniculate leaflet, olivary pretectal nucleus, and ventrolateral preoptic nucleus [10, 13–15] and act as the primary photoreceptors for NIF functions such as melatonin suppression [3, 6, 14, 16–18] and pupillary constriction [5, 7, 8, 14, 18–28]. Recently, it was pointed that the input from cones and rods could potentially affect the ipRGC response [11, 14, 18, 21, 29]. Most vertebrates, including fishes, amphibians, reptiles, and birds, have three or four types of cones and trichromatic or tetrachromatic color vision. However, in the history of evolution, mammals lost a portion of these cones and have dichromatic color vision. Some primates (catarrhines) acquired a third cone and have trichromatic color vision. Humans have three types of cones (S-cones, M-cones, and L-cones) and have trichromatic color vision [30, 31], which is rare in mammals. Figueiro et al. [29] studied the effects of blue (450 nm, 7.7 μW/cm) and green (525 nm, 21.1 μW/cm) light on melatonin suppression at night. They found that simultaneous exposure to blue and green light resulted in less melatonin suppression than monochromatic exposure to blue or green light. This effect is called the subadditive response to light [29]. Figueiro et al. [32, 33] and Revell et al. [34] also identified the subadditive effects of monochromatic and polychromatic light on melatonin suppression, suggesting that cones affected the ipRGC response. However, it remains unclear whether the subadditive response affects pupillary constriction. The response of mouse ipRGCs to a single photon was examined, and it became clear that ipRGCs have an exceptionally large and prolonged response in comparison with rods and cones [12]. However, ipRGCs are far less sensitive than rods and cones to light intensity [19, 21, 23, 35], so we hypothesized that exposure to high irradiance pulsed light might produce higher NIF function. Therefore, in the present study, we examined the effects of separate and simultaneous exposure to extremely short pulses of blue and green light at different * Correspondence: yisoomin@chiba-u.jp Center for Environment, Health and Field Sciences, Chiba University, 6-2-1, Kashiwanoha, Kashiwa 277-0882, Japan Full list of author information is available at the end of the article

Ergonomic design and evaluation of new surgical scissors

The purpose of this study is to design a new surgical scissors handle and determine its effectiveness with various usability indices. A new scissors handle was designed that retains the professional grip but has the shapes of the eye rings modified to fit the thumb and ring finger and finger rests for the index and little finger. The newly designed scissors and traditional scissors were compared by electromyography, subjective evaluation and task performance in experiments using cutting and peeling tasks. The newly designed scissors reduced muscle load in both hand during cutting by the closing action, and reduced the muscle load in the left hand during peeling by the opening action through active use of the right hand. In evaluation by surgeons, task performance improved in addition to the decrease in muscle load. The newly designed scissors used in this study demonstrated high usability. Practitioner Summary: A new scissors handle was designed that has the eye rings modified to fit the thumb and ring finger. The newly designed scissors reduced muscle load and enabled active use of the right hand. In evaluation by surgeons, task performance improved in addition to the decrease in muscle load.

Physiological responses at short distances from a parametric speaker

In recent years, parametric speakers have been used in various circumstances. In our previous studies, we verified that the physiological burden of the sound of parametric speaker set at 2.6 m from the subjects was lower than that of the general speaker. However, nothing has yet been demonstrated about the effects of the sound of a parametric speaker at the shorter distance between parametric speakers the human body. Therefore, we studied this effect on physiological functions and task performance. Nine male subjects participated in this study. They completed three consecutive sessions: a 20-minute quiet period as a baseline, a 30-minute mental task period with general speakers or parametric speakers, and a 20-minute recovery period. We measured electrocardiogram (ECG) photoplethysmogram (PTG), electroencephalogram (EEG), systolic and diastolic blood pressure. Four experiments, one with a speaker condition (general speaker and parametric speaker), the other with a distance condition (0.3 m and 1.0 m), were conducted respectively at the same time of day on separate days. To examine the effects of the speaker and distance, three-way repeated measures ANOVA (speaker factor x distance factor x time factor) were conducted. In conclusion, we found that the physiological responses were not significantly different between the speaker condition and the distance condition. Meanwhile, it was shown that the physiological burdens increased with progress in time independently of speaker condition and distance condition. In summary, the effects of the parametric speaker at the 2.6 m distance were not obtained at the distance of 1 m or less.

A User-friendly Video Camera Based on Ergonomic Studies

To design an ergonomically user-friendly video camera, electromyograms (EMGs) at six muscle locations were measured to find an optimal grip angle. Grip angle is an important factor in the usability of general consumer electronic products. The results indicated that vertically-gripped cameras, where the grip angle is large from the axis of the lens alignment, reduced muscular load. Particularly a grip angle from 105deg to 135deg produced little fatigue. In consideration of our results, we developed a compact and lightweight video camera with a grip angle of 105deg based on ergonomic methodology.