Non-Invasive Alcohol Concentration Measurement Using a Spectroscopic Module: Outlook for the Development of a Drunk Driving Prevention System.

Alcohol acts as a central nervous system depressant and falls under the category of psychoactive drugs. It has the potential to impair vital bodily functions, including cognitive alertness, muscle coordination, and induce fatigue. Taking the wheel after consuming alcohol can lead to delayed responses in emergency situations and increases the likelihood of collisions with obstacles or suddenly appearing objects. Statistically, drivers under the influence of alcohol are seven times more likely to cause accidents compared to sober individuals. Various techniques and methods for alcohol measurement have been developed. The widely used breathalyzer, which requires direct contact with the mouth, raises concerns about hygiene. Methods like chromatography require skilled examiners, while semiconductor sensors exhibit instability in sensitivity over measurement time and has a short lifespan, posing structural challenges. Non-dispersive infrared analyzers face structural limitations, and in-vehicle air detection methods are susceptible to external influences, necessitating periodic calibration. Despite existing research and technologies, there remain several limitations, including sensitivity to external factors such as temperature, humidity, hygiene consideration, and the requirement for periodic calibration. Hence, there is a demand for a novel technology that can address these shortcomings. This study delved into the near-infrared wavelength range to investigate optimal wavelengths for non-invasively measuring blood alcohol concentration. Furthermore, we conducted an analysis of the optical characteristics of biological substances, integrated these data into a mathematical model, and demonstrated that alcohol concentration can be accurately sensed using the first-order modeling equation at the optimal wavelength. The goal is to minimize user infection and hygiene issues through a non-destructive and non-invasive method, while applying a compact spectrometer sensor suitable for button-type ignition devices in vehicles. Anticipated applications of this study encompass diverse industrial sectors, including the development of non-invasive ignition button-based alcohol prevention systems, surgeon's alcohol consumption status in the operating room, screening heavy equipment operators for alcohol use, and detecting alcohol use in close proximity to hazardous machinery within factories.

Laser parameters for efficient biomedical stimulation: A study to increase cognitive response rate.

BACKGROUND: The laser is able to irradiate the exact amount of stimulation to an area by a non contact method, and has the advantage of being able to stimulate the local target area. OBJECTIVE: This study examined an efficient method of laser tactile stimulation using laser parameter combinations. METHODS: The laser parameters that could cause an increase in the cognitive response rate of human subjects were examined without increasing the amount of total laser energy. RESULTS: As a result, the appropriate matching parameters such as duty ratio, pulse frequency, and exposure time of laser pulses showed a dominant influence in effectively increasing the tactile response rate of subjects with limited amount of total laser energy. CONCLUSIONS: This study can be applied to neurophysiology, cognitive research, and clinical laser application.

A study on detection of glucose concentration using changes in color coordinates.

Glucose concentration is closely related to the metabolic activity of cells and it is the most important substance as the energy source of a living body which plays an important role in the human body. This paper proposes an optical method that can measure the concentration of glucose. The change in glucose concentration was observed by using CIE diagram, and wavelength and purity values were detected. Also, even small changes in glucose concentration can be evaluated through mathematical modeling. This system is simple, economical, and capable of quantifying optical signals with numerical values for glucose sensing. This method can be applicable to the clinical field that examines diabetes mellitus or metabolic syndrome.

Responses of human sensory characteristics to 532 nm pulse laser stimuli.

BACKGROUND: Lasers are advantageous in some applications to stimulate a small target area and is used in various fields such as optogenetic, photoimmunological and neurophysiological studies. OBJECTIVE: This study aims to implement a non-contact sense of touch without damaging biological tissues using laser. METHODS: Various laser parameters were utilized in safety range to induce a sense of touch and investigate the human responses. With heat distribution simulation, the amount of changes in the temperature and the tendency in laser parameters of sensory stimulation were analyzed. RESULTS: The results showed the identified tactile responses in safety range with various laser parameters and temperature distribution for the laser stimulus was obtained through the simulation. CONCLUSIONS: This study can be applied to the areas of sensory receptor stimulation, neurophysiology and clinical medicine.

Mid-Air Tactile Stimulation Using Indirect Laser Radiation.

In this paper, we demonstrate that a laser irradiated on a thin light-absorbing elastic medium attached on the skin can elicit a tactile sensation of mechanical tap. First, we present simulation results that show laser irradiation to the elastic medium creates inner elastic waves on the basis of thermoelastic effects and these elastic waves trigger the bending deformation of the medium, which then stimulates the skin. Second, we analyze the physical properties of the associated stimulus by measuring its force profile. Third, we identify the perceptual characteristics of the stimulus in comparison to those of mechanical and electrical stimuli by means of a perceptual experiment employing dissimilarity rating. All the evidence indicates that indirect laser radiation provides a sensation of short mechanical tap. Furthermore, little individual difference was observed in the results of the perceptual experiment. To the best of our knowledge, this study is the first in reporting the feasibility of indirect laser radiation for mid-air tactile rendering.

Study of somesthesis according to change in pulse diode laser parameters.

Laser can precisely deliver quantitative energy to a desired region in a non-contact way. Since it can stimulate regions and minutely control parameters such as the intensity, duration and frequency of stimulus, laser is often used for the areas such as low power laser treatment and clinical physiology. This study proposes simulation using pulse diode laser with reliable output and identifies laser parameters that can present a variety of somesthesis. It is found that typically, as frequency and energy increase, the ratio of feeling senses increases, and dominant sense moves from the sense of heat through tactile sense to pain. This study will be baseline data for studies of the sense of heat, tactile sense and pain, contribute to studying neurophysiology sector and be applied to basic clinical research.

Simple LED spectrophotometer for analysis of color information.

A spectrophotometer is the basic measuring equipment essential to most research activity fields requiring samples to be measured, such as physics, biotechnology and food engineering. This paper proposes a system that is able to detect sample concentration and color information by using LED and color sensor. Purity and wavelength information can be detected by CIE diagram, and the concentration can be estimated with purity information. This method is more economical and efficient than existing spectrophotometry, and can also be used by ordinary persons. This contribution is applicable to a number of fields because it can be used as a colorimeter to detect the wavelength and purity of samples.

Diverse effects of a 445 nm diode laser on isometric contraction of the rat aorta.

The usefulness of visible lasers in treating vascular diseases is controversial. It is probable that multiple effects of visible lasers on blood vessels and their unclear mechanisms have hampered the usefulness of this therapy. Therefore, elucidating the precise actions and mechanisms of the effects of lasers on blood vessels would provide insight into potential biomedical applications. Here, using organ chamber isometric contraction measurements, western blotting, patch-clamp, and en face immunohistochemistry, we showed that a 445 nm diode laser contracted rat aortic rings, both by activating endothelial nitric oxide synthase and by increasing oxidative stress. In addition to the effects on the endothelium, the laser also directly relaxed and contracted vascular smooth muscle by inhibiting L-type Ca(2+) channels and by activating protein tyrosine kinases, respectively. Thus, we conclude that exposure to 445 nm laser might contract and dilate blood vessels in the endothelium and smooth muscle via distinct mechanisms.

A new optical technique to monitor joint motion using position sensitive detector.

BACKGROUND: Evaluation of joint movements is essential to choose an appropriate rehabilitation protocol for a patient. OBJECTIVE: The aim of this study is to suggest an alternative optical technique for measurement of joint angle which is convenient, inexpensive, and can be operated in real time. METHODS: According to the principle of the triangulation method, position sensitive detector (PSD) converts reflected light signals into distance-related voltages. Various parameters were investigated to increase detection range and resolution of joint angle measurements. RESULTS: The accuracy of the suggested optical sensor was verified by comparing with a commercial goniometer and 3D motion capture system. CONCLUSIONS: This method can be applied to monitor recovery progress for the patient in rehabilitation and sport science.

Development of multi-colored LED system for therapeutic application.

BACKGROUND: The evaluation and control of lighting is crucial in physiological, biomedical, and industrial fields. Many kinds of lighting techniques based on LED have been developed due to its advantages. OBJECTIVE: The aim of this study is to develop the multi-colored LED system for healing purposes. METHODS: Light source with three-color chip LEDs was investigated to detect the dominant wavelength. RESULTS: The results show that the additive principle by three-color LEDs can be successfully applied to lighting system by generating a variety of colors. CONCLUSIONS: The results are expected to be useful in the field of light therapy and medicine. Applications of the developed light system are lighting therapies such as stimulating blood circulation and digestive processes, and controlling inflammation.

Photomechanical effect on Type I collagen using pulsed diode laser.

BACKGROUND: As the most abundant protein in human tissues, the use of collagen is essential in the fields of biological science and medicine. OBJECTIVE: The aim of this study is to investigate the mechanical effect of pulsed laser irradiation on collagen tissue. METHODS: With various laser parameters such as peak power, pulse width, and repetition rate, the induced stresses on samples were measured and analyzed. Monte Carlo simulation was performed to investigate the effect of laser parameters on the collagen sample. RESULTS: The results indicated that the magnitude of mechanical stress could be controlled by various laser parameters. CONCLUSIONS: This study can be used in biostimulation for therapy and mechanoreceptor stimulation for tactile application.

Evaluation of the possibility and response characteristics of laser-induced tactile sensation.

In this study, we examined the possibility and perceptual response characteristics of tactile sense induced by laser stimulation to the finger with different laser energy densities through human response experiments. 15 healthy adult males and 4 healthy adult females with an age of 22.6±2.2 years were tested. A frequency-doubled Q-switched laser was used with a wavelength of 532 nm and a 5 ns pulse width. The experimental trial spanned a total of 30 s and included a rest phase (19 s), a stimulation phase (7 s), and a response phase (4 s). During the rest phase, subjects kept their fingers comfortable. During the stimulation phase, one of three types of laser energy density (13.5, 16.6, 19.8 mJ/cm(2)) or a sham stimulation was used to irradiate the distal phalanx on the right index finger. During the response phase, the cognitive response to the laser stimulation was recorded by a PC by pressing the response button. The confusion matrix was configured to evaluate the possibility that the tactile sense was caused by the laser. In addition, changes in the response characteristics were observed according to three types of laser energy densities. From the analysis of the confusion matrix, the accuracy and sensitivity were not high. In contrast, precision and specificity were found to be high. Furthermore, there was a strong positive correlation between the laser irradiation and tactile perception, indicating that tactile sense can be induced using a laser in a mid-air manner. In addition, it was found that as the laser energy density increased, the tactile perception possibility also increased.

Laser-induced thermoelastic effects can evoke tactile sensations.

Humans process a plethora of sensory information that is provided by various entities in the surrounding environment. Among the five major senses, technology for touch, haptics, is relatively young and has relatively limited applications largely due to its need for physical contact. In this article, we suggest a new way for non-contact haptic stimulation that uses laser, which has potential advantages such as mid-air stimulation, high spatial precision, and long working distance. We demonstrate such tactile stimulation can be enabled by laser-induced thermoelastic effects by means of physical and perceptual studies, as well as simulations. In the physical study, the mechanical effect of laser on a human skin sample is detected using low-power radiation in accordance with safety guidelines. Limited increases (< ~2.5 °C) in temperature at the surface of the skin, examined by both thermal camera and the Monte Carlo simulation, indicate that laser does not evoke heat-induced nociceptive sensation. In the human EEG study, brain responses to both mechanical and laser stimulation are consistent, along with subjective reports of the non-nociceptive sensation of laser stimuli.

Feet distance and static postural balance: implication on the role of natural stance.

The purpose of this study was to investigate 1) the effect of feet distance on static postural balance and 2) the location of natural feet distance and its possible role in the relationship of feet distance and postural balance. Static balance tests were performed on a force platform for 100 s with six different feet distances (0, 5, 10, 15, 20, 25 cm). Measures of postural balance included mean amplitude of horizontal ground reaction force (GRF) as well as the mean distance and velocity of the center of pressure (COP). All measures were discomposed into anterioposterior and mediolateral directions. ANOVA and post-hoc comparison were performed for all measures with feet distance as an independent factor. Also measured was the feet distance at the natural stance preferred by each subject. All measures significantly varied with feet distance (p<0.001). Mean distance of COP showed monotonic decrease with feet distance. Mean amplitude of horizontal GRF as well as mean velocity of COP showed U-shaped pattern (decrease followed by increase) with the minimum at the feet distance of 15 cm or 20 cm, near which the natural feet distance of 16.5 (SD 3.8) cm was located. COP is regarded to be an approximation of the center of mass (hence the resultant performance of postural control) in an inverted pendulum model with the horizontal GRF ignored. On the other hand, horizontal GRF is the direct cause of horizontal acceleration of a center of mass. The present result on horizontal GRF shows that the effort of postural control is minimized around the feet distance of natural standing and implies why the natural stance is preferred.

Age-gender differences in the postural sway during squat and stand-up movement.

Incidence of falling among elderly female has been reported to be much higher than that of elderly male. Although the gender differences in the elderly were reported for the static postural sway, there has been no investigation of the gender difference for the dynamic postural sway. This study investigates how age and gender affect the postural sway during dynamic squat and stand-up movement. 124 subjects (62 subjects for each of young and elderly) performed consecutive squat and stand-up movement, 2 times in one session, and 2 sessions per subject. Center of pressure (COP) was measured using force platform during the test. Outcome measures included peak-to-peak sways of the COP (COP sway) in the sagittal plane (anteroposterior) and frontal plane (mediolateral) and also those normalized by body height. Two-way ANOVA and post-hoc comparisons were performed for the outcome measures with the independent factors of age and gender. All outcome measures, excluding mediolateral COP sway, showed significant interaction of age and gender (p<0.05). Post-hoc test revealed that only female showed increase in COP sway with age. When normalized by height, increase in COP sways (both directions) with age significant only in women resulted in greater sways in elderly female than elderly male. This may be related to the greater fall rate of elderly female than that of elderly men while performing dynamic activities.

Development of an optical fiber sensor for angular displacement measurements.

For diagnostic and therapeutic purposes, the joint angle measurement of a patient after an accident or a surgical operation is significant for monitoring and evaluating the recovering process. This paper proposed an optical fiber sensor for the measurement of angular displacement. The effect of beveled fiber angle on the detected light signal was investigated to find an appropriate mathematical model. Beveled fiber tips redirected the light over a range of angles away from the fiber axis. Inverse polynomial models were applied to directly obtain and display the joint angle change in real time with the Lab-VIEW program. The actual joint angle correlated well with the calculated LabVIEW output angle over the test range. The proposed optical sensor is simple, cost effective, small in size, and can evaluate the joint angle in real time. This method is expected to be useful in the field of rehabilitation and sport science.

Development of a simple pressure and heat stimulator for intra- and interdigit functional magnetic resonance imaging.

For this study, we developed a simple pressure and heat stimulator that can quantitatively control pressure and provide heat stimulation to intra- and interdigit areas. The developed stimulator consists of a control unit, drive units, and tactors. The control unit controls the stimulation parameters, such as stimulation types, intensity, time, and channel, and transmits a created signal of stimulation to the drive units. The drive units operate pressure and heat tactors in response to commands from the control unit. The pressure and heat tactors can display various stimulation intensities quantitatively, apply stimulation continuously, and adjust the stimulation areas. Additionally, they can easily be attached to and detached from the digits. The developed pressure and heat stimulator is small in total size, easy to install, and inexpensive to manufacture. The new stimulator operated stably in a magnetic resonance imaging (MRI) environment without affecting the obtained images. A preliminary functional magnetic resonance imaging (fMRI) experiment confirmed that differences in activation of somatosensory areas were induced from the pressure and heat stimulation. The developed pressure and heat stimulator is expected to be utilized for future intra- and interdigit fMRI studies on pressure and heat stimulation.

Age-gender differences in the reaction times of ankle muscles.

AIM: Reaction times of the hip abductor were reported to be longer in elderly women than in elderly men, and this was suggested to be related to mediolateral balance performance. The aim of the present study was to investigate the effects of age and gender on the reaction performance of ankle muscles, which have predominant roles in anterioposterior balance control. METHODS: A total of 40 elderly subjects and 40 young subjects (even number of men and women) carried out a series of isometric plantarflexions and dorsiflexions, as forcefully and quickly as possible, in response to auditory stimulus. Surface electromyogram at the dorsiflexor and plantarflexor were recorded, together with foot plantar force. Premotor time, motor time and total reaction time derived from the experimental data were compared between age groups and genders by two-way anova. RESULTS: Both dorsiflexor and plantarflexor showed similar reaction performance. Premotor time increased with age with no gender difference. Motor time increased with age in women and not in men, resulting in longer motor time in elderly women than in elderly men. Total reaction time was dominated by premotor time, so that it was longer in the elderly with no gender difference. CONCLUSION: Although age-related elongation of motor time was greater in women, total reaction time was not different between the genders. This may be related to no gender difference in anterioposterior balance performance.

Effects of three levels of arousal on 3-back working memory task performance.

This study investigated how three levels of arousal affected performance of a 3-back working memory task. Ten female and ten male university students participated in this experiment. With pictures selected from a group test, three levels of arousal were induced--i.e., tense, neutral, and relaxed emotions. Each subject was run through the procedure three times, once for each arousal level. The procedure consisted of six phases for each arousal condition: (1) Rest 1 (2 min), (2) Picture 1 (presenting emotion arousing photos for 2 min), (3) 3-back working memory task 1 (2 min), (4) Picture 2 (presenting emotion-arousing photos for 2 min), (5) 3-back working memory task 2 (2 min), and (6) Rest 2 (2 min). The skin conductance level of electrodermal activity was also measured during all phases of the experiment. The accuracy rate of 3-back working memory task performance was the highest at a neutral emotional state, followed by relaxed and then tense emotional states. There were no significant differences in reaction time.

Development of a tactile stimulator with simultaneous visual and auditory stimulation using E-Prime software.

In this study, a tactile stimulator was developed, which can stimulate visual and auditory senses simultaneously by using the E-Prime software. This study tried to compensate for systematic stimulation control and other problems that occurred with previously developed tactile stimulators. The newly developed system consists of three units: a control unit, a drive unit and a vibrator. Since the developed system is a small, lightweight, simple structure with low electrical consumption, a maximum of 35 stimulation channels and various visual and auditory stimulation combinations without delay time, the previous systematic problem is corrected in this study. The system was designed to stimulate any part of the body including the fingers. Since the developed tactile stimulator used E-Prime software, which is widely used in the study of visual and auditory senses, the stimulator is expected to be highly practical due to a diverse combination of stimuli, such as tactile-visual, tactile-auditory, visual-auditory and tactile-visual-auditory stimulation.