The human visual sensitivity to the flickering light has been under investigation for decades.The finding of research in this area can contribute to the understanding of human visual system mechanism and visual disord...The human visual sensitivity to the flickering light has been under investigation for decades.The finding of research in this area can contribute to the understanding of human visual system mechanism and visual disorders,and establishing diagnosis and treatment of diseases.The aim of this study is to investigate the ffects of the flickering light to the visual cortex by monitoring the hemodynamic responses of the brain with the functional near infrared spectrosoopy(ENIRS)method.Since the acquired fNIRS signals are afected by physiological factors and measurement artifacts,constrained independent component analysis(eICA)was applied to extract the actual fNIRS responses from the obtained data.The experimental results revealed significant changes(p<0.0001)of the hemodynamic responses of the visual cortex.from the baseline when the flickering stimulation was activated.With the uses of cICA,the contrast to noise ratio(CNR),reflecting the contrast of hemodynamic concentration between rest and task,became larger.This indicated the improvement of the NIRS signals when the noise was eliminated.In subsequent studies,statistical analysis was used to infer the correlation between the NIRS signals and the visual stimulus.We found that there was a slight decrease of the oxygenated hemoglobin con-centration(about 5.69%)over four frequencies when the modulation increased.However,the variations of oxy and deoxy-hemoglobin were not statistically significant.展开更多
A novel injectable hydrogel that was synthesized by in situ crosslinking of hyaluronan and polyvinyl phosphonic acid was proposed in this study. Fourier transform infrared spectrum (FT-IR) analysis, scanning electron ...A novel injectable hydrogel that was synthesized by in situ crosslinking of hyaluronan and polyvinyl phosphonic acid was proposed in this study. Fourier transform infrared spectrum (FT-IR) analysis, scanning electron microscope (SEM), pH measurement, and biodegradation test were used to confirm its characteristics. The results permitted to prove successful crosslinking, observe the inner morphology of hydrogel and pore sizes distribution, and determine the decomposition of hydrogel components during incubation time. Result of pH measurement showed that the pH scale of hydrogel decreased when volume of PVPA increased. As a consequence, it affected the cytotoxicity value, cell proliferation, and cell growth behaviors of each hydrogel. Optical microscope observation showed that chondroblasts cell proliferated well on HA-PVPA hydrogel. Therefore, these results suggest that the new injectable hydrogel is appropriate for bone/cartilage regeneration applications.展开更多
This paper represented Autoregressive Neural Network (ARNN) and meant threshold methods for recognizing eye movements for control of an electrical wheelchair using EEG technology. The eye movements such as eyes open, ...This paper represented Autoregressive Neural Network (ARNN) and meant threshold methods for recognizing eye movements for control of an electrical wheelchair using EEG technology. The eye movements such as eyes open, eyes blinks, glancing left and glancing right related to a few areas of human brain were investigated. A Hamming low pass filter was applied to remove noise and artifacts of the eye signals and to extract the frequency range of the measured signals. An autoregressive model was employed to produce coefficients containing features of the EEG eye signals. The coefficients obtained were inserted the input layer of a neural network model to classify the eye activities. In addition, a mean threshold algorithm was employed for classifying eye movements. Two methods were compared to find the better one for applying in the wheelchair control to follow users to reach the desired direction. Experimental results of controlling the wheelchair in the indoor environment illustrated the effectiveness of the proposed approaches.展开更多
基金supported by Vietnam National University-Ho Chi Minh City research grant B2011-28-01.
文摘The human visual sensitivity to the flickering light has been under investigation for decades.The finding of research in this area can contribute to the understanding of human visual system mechanism and visual disorders,and establishing diagnosis and treatment of diseases.The aim of this study is to investigate the ffects of the flickering light to the visual cortex by monitoring the hemodynamic responses of the brain with the functional near infrared spectrosoopy(ENIRS)method.Since the acquired fNIRS signals are afected by physiological factors and measurement artifacts,constrained independent component analysis(eICA)was applied to extract the actual fNIRS responses from the obtained data.The experimental results revealed significant changes(p<0.0001)of the hemodynamic responses of the visual cortex.from the baseline when the flickering stimulation was activated.With the uses of cICA,the contrast to noise ratio(CNR),reflecting the contrast of hemodynamic concentration between rest and task,became larger.This indicated the improvement of the NIRS signals when the noise was eliminated.In subsequent studies,statistical analysis was used to infer the correlation between the NIRS signals and the visual stimulus.We found that there was a slight decrease of the oxygenated hemoglobin con-centration(about 5.69%)over four frequencies when the modulation increased.However,the variations of oxy and deoxy-hemoglobin were not statistically significant.
文摘A novel injectable hydrogel that was synthesized by in situ crosslinking of hyaluronan and polyvinyl phosphonic acid was proposed in this study. Fourier transform infrared spectrum (FT-IR) analysis, scanning electron microscope (SEM), pH measurement, and biodegradation test were used to confirm its characteristics. The results permitted to prove successful crosslinking, observe the inner morphology of hydrogel and pore sizes distribution, and determine the decomposition of hydrogel components during incubation time. Result of pH measurement showed that the pH scale of hydrogel decreased when volume of PVPA increased. As a consequence, it affected the cytotoxicity value, cell proliferation, and cell growth behaviors of each hydrogel. Optical microscope observation showed that chondroblasts cell proliferated well on HA-PVPA hydrogel. Therefore, these results suggest that the new injectable hydrogel is appropriate for bone/cartilage regeneration applications.
文摘This paper represented Autoregressive Neural Network (ARNN) and meant threshold methods for recognizing eye movements for control of an electrical wheelchair using EEG technology. The eye movements such as eyes open, eyes blinks, glancing left and glancing right related to a few areas of human brain were investigated. A Hamming low pass filter was applied to remove noise and artifacts of the eye signals and to extract the frequency range of the measured signals. An autoregressive model was employed to produce coefficients containing features of the EEG eye signals. The coefficients obtained were inserted the input layer of a neural network model to classify the eye activities. In addition, a mean threshold algorithm was employed for classifying eye movements. Two methods were compared to find the better one for applying in the wheelchair control to follow users to reach the desired direction. Experimental results of controlling the wheelchair in the indoor environment illustrated the effectiveness of the proposed approaches.
