61 research outputs found

    Toxic wavelength of blue light changes as insects grow

    Get PDF
    <div><p>Short-wavelength visible light (blue light: 400–500 nm) has lethal effects on various insects, such as fruit flies, mosquitoes, and flour beetles. However, the most toxic wavelengths of blue light might differ across developmental stages. Here, we investigate how the toxicity of blue light changes with the developmental stages of an insect by irradiating <i>Drosophila melanogaster</i> with different wavelengths of blue light. Specifically, the lethal effect on eggs increased at shorter light wavelengths (i.e., toward 405 nm). In contrast, wavelengths from 405 to 466 nm had similar lethal effects on larvae. A wavelength of 466 nm had the strongest lethal effect on pupae; however, mortality declined as pupae grew. A wavelength of 417 nm was the most harmful to adults at low photon flux density, while 466 nm was the most harmful to adults at high photon flux density. These findings suggest that, as the morphology of <i>D</i>. <i>melanogaster</i> changes with growth, the most harmful wavelength also changes. In addition, our results indicated that reactive oxygen species influence the lethal effect of blue light. Our findings show that blue light irradiation could be used as an effective pest control method by adjusting the wavelength to target specific developmental stages.</p></div

    A New Laparoscopic Surgical Procedure to Achieve Sufficient Mesorectal Excision in Upper Rectal Cancer

    Get PDF
    Objective. Mesorectal excision corresponding to the location of a tumor, termed tumor-specific mesorectal excision (TSME), is commonly performed for resection of upper rectal cancer. We devised a new laparoscopic procedure for sufficient TSME with rectal transection followed by mesorectal excision. Operative Technique. After mobilization of the sigmoid colon and ligation of inferior mesenteric vessels, we dissected the mesorectum along the layer of the planned total mesorectal excision. The rectal wall was carefully separated from the mesorectum at the appropriate anal side from the tumor. After the rectum was isolated and transected using an endoscopic linear stapler, the rectal stump drew immediately toward the anal side, enabling the mesorectum to be identified clearly. In this way, sufficient TSME can be performed easily and accurately. This technique has been successfully conducted on 19 patients. Conclusion. This laparoscopic technique is a feasible and reliable procedure for achieving sufficient TSME

    The Relationship between Inferior Vena Cava Distensibility and Arterial Blood Pressure

    Get PDF
    The purpose of this study was to clarify the relationship between the inferior vena cava distensibility and blood pressure. Six Japanese healthy males volunteered to participate in this study. We measured the cross-sectional area of inferior vena cava (CSAivc) and blood pressure at rest and during passive leg raising in supine position. We calculated the change rates of each parameter, based on the value at rest in supine position. We observed a negative correlation between the change rate of CSAivc and systolic blood pressure (P<0.05). These results suggest that the inferior vena cava distensibility affects partially systolic blood pressure

    Effects of Eating or Skipping Breakfast on Heart Rate and Oxygen Uptake

    Get PDF
    The purpose of this study was to compare changes in heart rate, oxygen uptake, blood pressure and oral temperature between subjects eating breakfast and subjects skipping breakfast when they exercise each day at 11:00 AM and 2:00 PM. The study design included two different groups, a breakfast group and a skipping group. Subjects rested for five minutes, and they exercised on a pendulum ergometer for twenty minutes. After exercising, the resistance was returned to zero for a one minute cool down followed by five more minutes of complete rest(recovery phase). Oral temperatures of the skipping group were lower than those of the breakfast group at 11:00 AM. Diet induced thermogenesis (DIT), which increases core body temperature, is generated by eating breakfast. In the skipping group, the resting heart rates at 11:00 AM were lower than at 2:00 PM. A significant difference in heart rate after the first minute of exercise was seen between 11:00 AM and 2:00 PM in the skipping group. These results suggested that when skipping breakfast, the heart rate response immediately after beginning exercise is slow in the morning. Although all subjects did cooling down for one minute after exercising, oxygen uptake during the recovery phase in the skipping group at 11:00 AM was significantly higher than at rest. These results suggest that eating breakfast has a physiological influence on both heart rate and oxygen uptake

    Circadian variations in anaerobic threshold

    Get PDF
    This study aimed to determine whether certain respiratory and cardiovascular parameters associated with anaerobic threshold (AT), measured during graded exercise testing, occur at lower intensities in the morning than in the evening. Ten healthy Japanese men volunteered to participate in this study, which involved two conditions that were performed at different times of day: morning (M) exercise was performed between 9:00 and 10:00 a.m., and afternoon (A) exercise was performed between 4:00–6:00 p.m. After resting supine for 30 minutes, each subject performed graded cycle ergometer exercise testing comprising 90-second stages. Exercise intensity was initially 10 W and was increased by 10 W for each stage. Heart rate (HR), blood pressure (BP), absolute double product (DP), cardiac autonomic nervous system modulation, and ventilatory volume (VE) were measured during each exercise stage. Ventilatory threshold (VT), the double product breaking point (DPBP), and breaking point of the natural log of high frequency (ln HF) (HFBP) were reached at a lower exercise intensity in the M condition than in the A condition (p<.05). Values for VE at VT intensity, DP, HR, and systolic blood pressure (SBP) at DPBP were significantly lower in the M condition than in the A condition (p<.05). These data suggest that AT is reached at a lower intensity in the morning than in the afternoon, and that relative burden, as indicated by HR and SBP, is greater in the morning than in the afternoon. Exercise prescriptions that incorporate awareness of the circadian rhythms may prevent cardiac or cerebrovascular accidents during exercise

    Effect of Environmental Change while Climbing Mt. Daisen on Forced Vital Capacity and Forced Expiratory Volume % in Young Women

    Get PDF
    The aim of the present study was to clarify the effects of environmental change while climbing Mt. Daisen on forced vital capacity and forced expiratory volume % in young women in summer. Seven healthy Japanese women (age: 22.6 ± 4.2 years) volunteered to climb Mt. Daisen (1,709m), located in Tottori prefecture, in August. Participants\u27 expiratory forced vital capacity (FVC), forced expiratory volume % (FEV_%) and arterial oxygen saturation (SpO_2) were measured at 4 points (Ground: 10m, Rest point: 780m, Summit: 1,709m, Goal point: 780m). The measurements were conducted soon after the subjects\u27 arrival at each point. The degree of dyspnea sensation was measured at Ground, Rest point, Goal point and at each station. There were no significant changes in FVC. FEV_% at the summit was significantly lower than at the Ground and Rest point. No significant differences were found in SpO_2 at each measuring point. The degree of dyspnea sensation at each station soon after the subjects\u27 arrival was significantly higher than those at the Rest point. The results of this study indicated mild airway contraction induced by stresses on the respiratory system from increasing exercise intensity during an ascent of Mt. Daisen
    corecore