Fabrication of Functional Gel-Microbead for Local Environment Measurement in Microchip

Proceedings of the 2008 IEEE International Conference on Robotics and Automation / 2008 IEEE International Conference on Robotics and Automation, Pasadena, CA, USA, May 19-23, 200

Gel-tool Sensor Positioned by Optical Tweezers for Local pH Measurement in a Microchip

2007 IEEE International Conference on Robotics and Automation, Roma, Italy, 10-14 April 200

Effects of Coffee Intake on Oxidative Stress During Aging-related Alterations in Periodontal Tissue

Background/aim: The purpose of this study was to determine the anti-aging effects of coffee intake on oxidative stress in rat periodontal tissue and alveolar bone loss. Materials and methods: Male Fischer 344 rats (8 weeks old) were randomized to four groups; the baseline group immediately sacrificed, the control group fed with normal powdered food for 8 weeks, and the experimental groups fed with powdered food containing 0.62% or 1.36% coffee components for 8 weeks. Results: Alveolar bone loss and gingival level of 8-hydroxydeoxyguanosine were significantly lower in the 1.36% coffee group than in the control group. Nuclear factor erythroid 2-related factor 2 translocation to the nucleus was significantly higher in the 1.36% coffee group than in the control group. Conclusion: Continuous intake of 1.36% coffee could prevent age-related oxidative stress in the periodontal tissue and alveolar bone loss, possibly by up-regulating the Nrf2 signaling pathway

Temperature Changes in Brown Adipocytes Detected with a Bimaterial Microcantilever

AbstractMammalian cells must produce heat to maintain body temperature and support other biological activities. Methods to measure a cell’s thermogenic ability by inserting a thermometer into the cell or measuring the rate of oxygen consumption in a closed vessel can disturb its natural state. Here, we developed a noninvasive system for measuring a cell’s heat production with a bimaterial microcantilever. This method is suitable for investigating the heat-generating properties of cells in their native state, because changes in cell temperature can be measured from the bending of the microcantilever, without damaging the cell and restricting its supply of dissolved oxygen. Thus, we were able to measure increases in cell temperature of <1 K in a small number of murine brown adipocytes (n = 4–7 cells) stimulated with norepinephrine, and observed a slow increase in temperature over several hours. This long-term heat production suggests that, in addition to converting fatty acids into heat energy, brown adipocytes may also adjust protein expression to raise their own temperature, to generate more heat. We expect this bimaterial microcantilever system to prove useful for determining a cell’s state by measuring thermal characteristics

Relationship Between Renal Dysfunction and Oral Mucositis in Patients Undergoing Concurrent Chemoradiotherapy for Pharyngeal Cancer: A Retrospective Cohort Study.

BACKGROUND/AIM: The aim of this retrospective cohort study was to investigate the association between renal dysfunction (RD) and the development of oral mucositis (OM) in patients undergoing concurrent chemoradiotherapy (CCRT) for pharyngeal cancer including radiation to the oral cavity. PATIENTS AND METHODS: Of 130 patients diagnosed as having pharyngeal cancer who received CCRT at the Okayama University Hospital Head and Neck Cancer Center, 44 were finally selected. RESULTS: During the observation period, 24 (54.5%) patients experienced severe OM (grade 3). The Cox proportional hazards regression model demonstrated that RD (hazard ratio(HR)=2.45, 95% confidence interval(CI)=1.067-6.116, p=0.035) and nasopharynx/oropharynx as center of the irradiated area (HR=2.56, 95% CI=1.072-5.604, p=0.034) were significantly associated with the incidence of severe OM (grade 3). CONCLUSION: In patients with pharyngeal cancer treated with CCRT including radiation to the oral cavity, RD at baseline can be a risk factor for developing severe OM

Weight Illusion Caused by Sinusoidal Vibration Correlates with Grip Force Adjustment

Our research team previously identified a weight illusion in which a lifted object feels heavy when it continuously presents a sinusoidal vibration to the fingertips. However, the mechanism underlying this illusion remains unknown. We thus hypothesized that the autonomous grip force adjustment against a vibrating object would be one of the factors underlying the weight illusion. The autonomous grip force adjustment increases the motor outputs of a human hand system, subsequently raising the sense of effort to keep holding the lifted object. The grip forces and perceived heaviness were evaluated using vibratory stimuli with five different frequencies (30 Hz, 60 Hz, 100 Hz, 200 Hz, and 300 Hz) and three different amplitudes (156 μm, 177 μm, and 203 μm). The results showed that the stimuli at lower frequencies or large amplitudes increased the grip forces more and felt heavier than the stimuli at higher frequencies or small amplitudes. Specifically, the 30 Hz stimuli felt the heaviest and increased the grip force the most. An increase in the grip force was positively correlated with the perceived heaviness. These results indicate that vibratory stimuli influence both the grip force and weight perception. Our findings can contribute to developing haptic displays to present virtual heaviness

Three-Dimensional Blood Vessel Model with Temperature-Indicating Function for Evaluation of Thermal Damage during Surgery

Surgical simulators have recently attracted attention because they enable the evaluation of the surgical skills of medical doctors and the performance of medical devices. However, thermal damage to the human body during surgery is difficult to evaluate using conventional surgical simulators. In this study, we propose a functional surgical model with a temperature-indicating function for the evaluation of thermal damage during surgery. The simulator is made of a composite material of polydimethylsiloxane and a thermochromic dye, which produces an irreversible color change as the temperature increases. Using this material, we fabricated a three-dimensional blood vessel model using the lost-wax process. We succeeded in fabricating a renal vessel model for simulation of catheter ablation. Increases in the temperature of the materials can be measured by image analysis of their color change. The maximum measurement error of the temperature was approximately −1.6 °C/+2.4 °C within the range of 60 °C to 100 °C

Hydrogel Heart Model with Temperature Memory Properties for Surgical Simulation

The continual development of surgical technology has led to a demand for surgical simulators for evaluating and improving the surgical technique of surgeons. To meet these needs, simulators must incorporate a sensing function into the organ model for evaluating the surgical techniques. However, it is difficult to incorporate a temperature sensor into the conventional cardiac training model. In this study, we propose a heart model for surgical training of cardiac catheter ablation made from hydrogel, which has temperature memory properties. The heart model consists of a photo-crosslinkable hydrogel mixed with an irreversible temperature indicator that exhibits a color change from magenta to colorless at 55 &deg;C. The Young's modulus, electrical resistivity, thermal conductivity, and specific heat capacity of the hydrogel material were evaluated and compared with those of human heart. Furthermore, temperature calibration based on the color of the hydrogel material confirmed that the temperature measurement accuracy of the material is &plusmn; 0.18 &deg;C (at 56 &deg;C). A heart model for catheter ablation was fabricated using the hydrogel material and a molding method, and the color change due to temperature change was evaluated