2020年は新型コロナウイルス感染症（COVID-19）に始まり，COVID-19に終わる1年だった。本特集号の企画段階から出版に至るまでCOVID-19パンデミックに翻弄され続けた点では前代未聞のことだった。最初の緊急事態宣言が発出されたのは2020年4月7日であったが，ちょうど

DNA microarray technique is widely used to measure expressions of thousands of genes simultaneously. Data from this technique have a unique form; the number of parameters (genes) is huge whereas the number of measuring conditions (such as patients, time points, and cell lineages) is relatively small. Accordingly, data processing should be performed carefully. In particular, a method to narrow down the number of candidate genes is important to obtain meaningful results. In this paper, such techniques are discussed from different perspectives. First, a method to extract differentially expressed genes, which are the candidates of responsible genes, is introduced. In this method, a threshold for differential expression is determined depending on an expression level of each gene. Then some methods to find pathways, which show chemical relationships between genes, responsible for the differences in expression are described with an example from ventilator-associated lung injury.

The surface electromyography (EMG) is used to evaluate skeletal muscle, mainly in the clinical and sports science fields. Muscular activity is regulated by types and number of motor units (MUs). The action potential generated by MUs are measured as EMG. Most of the use of surface EMG is to evaluate the amount of muscle activity by amplitude information. Although surface EMG contains information on the activities of many MUs, these analyzes are rarely performed. We have developed a new method to extract conduction waves by focusing on the conduction of the potential waveform using a multi-channel surface EMG. By this method, it can be examined that the information on the emission of action potentials from motor nerves. We gave an overview of this method and its development. The method finds pairs of similar waveforms as conduction waves by quantitative judgment automatically. Since the position of conduction waves can be confirmed automatically, the position of the end-plate can be found. Also, depending on the research, it is possible to determine the angle of muscle fibers automatically. We are also studying the relationship between muscle thickness and conduction waves for diagnosis of muscle condition.

In recent years, various sensors for biomagnetic measurement have been researched and developed. These are mainly for low frequency small signals such as magnetocardiography. Optical pumped atomic magnetometer (OPAM) would rather be applicable to this high frequency signal since there is a valid signal at higher frequencies. However, the highly sensitive OPAM uses a magnetic shield and an anti-vibration table, which makes the OPAM system larger. By packing the optical system in one case, you can develop an OPAM module that can measure even while moving. As a result, by using a phase-locked loop, we have achieved a sensitivity of 2.548 pT/Hz^1/2 for a 100 kHz magnetic signal in the presence of a bias magnetic field and electromagnetic noise.

Misoperations and breakdowns of life-sustaining systems can lead to patient harm. Among the life-sustaining systems, the ventilator has the greatest number of accidents reported at present. This study developed an application for the troubleshooting of ventilators using an Augmented Reality (AR) device and tested its performance. Our application using AR glass could receive real-time monitoring information and the alarm ID sent from the ventilator at nominal intervals of 10 msec. The alarm troubleshooting guide contains the flow and pressure information in graphs, the alarm names, and the troubleshooting guide displayed at the upper center, lower center, center left, and right of the field of view, respectively, thus providing the operator with hands-free information. The AR device received real-time monitoring and alarm information from the ventilator, and appropriate techniques for dealing with alarms were presented to the operator. This application is designed for simulation-based training for detecting a ventilator alarm and is expected to improve the safety of medical care.

The direction of postural sway in response to neck dorsal muscle stimulation can be influenced by change in gaze direction or direction of auditory stimulation. A previous study has reported that the sway directions by gaze change and auditory stimulation are correlated and that the degree of influence differs from the left to right side. However, mechanisms for the correlated response and lateral difference remain largely unknown. Aiming at uncovering the mechanisms, this study further investigated the postural responses by the gaze change and auditory stimulation with more subjects. In addition, attention by auditory stimulation was investigated using line-motion illusion because we hypothesized that the mechanisms are related to the direction of attention. Fifty-two subjects participated in the following measurements: We measured the sway direction during gaze change to the left or right and auditory stimulation from the left or right. The correlation coefficients between the measured directions were significant on both sides. In 24 out of the 52 subjects, the line-motion illusion with a preceding auditory stimulation was observed frequently. The results suggest that the auditory stimulation can also cause attention, implying that postural sway occurs in the direction of attention attracted by the gaze or auditory stimulation.

The elucidation of muscle activity is important in clinical fields such as diagnosis of sarcopenia. Muscular activity is regulated by types and number of motor units (MU). The action potential generated by MUs are measured as electromyography (EMG). The multi-channel surface EMG (sEMG) is used to analyze the conduction of muscle potential. It is recorded as the interference electric potential generated by MUs. In our previous study, we proposed a method for searching all conducting waves appearing quantitatively in the multi-channel sEMG by calculating the similarity of the waveforms. It has possibility to estimate the mobilization of MUs by examining conduction waves. However, consideration of the results required anatomical and physiological knowledge. One of the quantitative evaluations of muscles is the measurement of muscle thickness using ultrasonic images. In this study, we investigated the relationship between conducting waves and muscle thickness measurement on 10 subjects. We examined the frequency of muscle training, muscle thickness, and the multi-channel sEMG during isometric contraction for each subject. It was found that the conduction velocity of waves is related to the biceps muscle thickness. In addition, the number of conducting waves is related to the ratio of biceps muscle thickness to subcutaneous fat thickness.

We have suggested the current-induced magnetic modulation spectroscopy (CIMMS) to detect human cardiopulmonary activity in sediment for lifesaving. Initially, a Finite Element (FE) model of human in sediment was developed to simulate impedance change by human cardiopulmonary activity and an optimal electrode arrangement was estimated to detect the activity at burial distance of 47mm, 97mm and 147mm. The estimated electrode arrangement was 427mm apart for current injection and 305mm apart for voltage difference detection. The impedance changes at burial distance of 47mm, 97mm and 147mm were 0.0635%, 0.0432% and 0.0278% caused by respiration and were 0.0006%, 0.0004% and 0.0003% caused by pulsation respectively. Secondly, cardiopulmonary activity of a normal male subject was measured with an electrode contactless electrical impedance spectroscopy (EIS) device using the estimated optimal electrode arrangement. Respiration and pulsation at the distance of 50mm had shown good agreement between a medical equipment and impedance measurement device. However, the accuracy was worse significantly at the distance of 100mm and 150mm gradually. Finally, we calculated the sensitivity difference between EIS and CIMMS and concluded that it would be possible to detect human cardiopulmonary activity in sediment when we use the CIMMS.

The purpose of this study is to examine the difference in the characteristics of the conducting waves obtained by the difference in the electrode shape and the muscle contraction state. The electrode proposed this time is one in which two kinds of electrodes of different sizes are alternately arranged in a row, eight electrodes each. The analysis was performed using the multi-channel method. From the experimental results, it was found that by making the electrode bigger, the number of conducting waves increases. Although the number of conducting waves was small with a small electrode, it was found that conducting waves of various patterns could be obtained and consider more detailed about muscle contraction.

This paper discusses the photoplethysmographic amplitude (PPGA) obtained from smartwatch. In recent years, the number of patients with mental illness due to mental stress has been increasing. Thereby, the evaluation of mental stress in daily life is necessary to prevent the mental illness. The conventional evaluation of mental stress uses biological information such as respiration, heart rate, saliva and photoplethysmography (PPG). Among them, PPG is measurable by a smartwatch daily. Therefore, we examined whether it is possible to evaluate the mental stress using PPG obtained by a smartwatch. In the mental stress evaluation, we focused on the PPGA, which is the characteristic point of PPG. This amplitude is able to evaluate the mental stress even with intermittent data. This is suitable for evaluation of smartwatches when the data may not obtain due to body movements. By contrast, the accuracy of acquiring PPGA of a smartwatch might be low due to various factors such as changes in blood flow or skin temperature. Hence, in this research, we proposed a correction method to obtain a stable and accurate PPGA. In the experiment, the effectiveness of this method examined by comparing the data of the photoplethysmograph and the corrected data of smartwatch after measuring with the photoplethysmograph and the smartwatch simultaneously.

We have developed a scalar-type optically pumped magnetic gradiometer for biomagnetism measurements in the earth’s magnetic field. In this study, a magnetic field simulating a magnetocardiogram could be detected without a magnetic shield. Biomagnetic measurements have advantages such as non-contact and source estimation. The optical pumped atomic magnetometer (OPAM) is a small size and can operate at room temperature, so it is possible to replace the superconducting quantum interference device (SQUID).

This paper examined character input using tilting motion and back tap for a smartphone.

Character input in smartphones has a problem such as erroneous input and large size input screen. To solve these problems, a multi-choice input method with a low degree of freedom had been designed to be able to input to sixty-four characters by flicking four buttons in two directions up and down and repeating it twice.

Besides, it was possible to input not only by touch, proposing four alternatives and a method of dividing these alternatives into two. In this research, the aim is to develop a multi-choice input interface with a low degree of freedom, in which four actions are taken by moving corners of the device closer and far from the body, and eight actions are performed by tapping the back of the device before performing these actions.

The three-axis acceleration sensor of smartphone was used to determine the movement. For the tilt movement, it was possible to determine using the z-axis or y-axis and the phase of the x-axis and y-axis. For the back tap, discrimination could be performed by the z-axis. Accordingly, all movements could be determined the average was 90% more.

Eyelid dysfunction results in symptoms of ptosis and eyelid retraction. Indicators of eyelid function include the corneal reflection distance at the eyelid margin and eyelid fissure (PF). There is currently no system in Japan that automatically measures the PF, which is a comprehensive measure of eyelid function. We devised a method to measure PF automatically from frontal images using ArUco markers and facial landmark estimation, and developed an implementation of the method using OpenCV and dlib. The system was shown to be significantly smaller than the digital calipers.

Atomic layer deposition (ALD), which is a type of chemical vapor deposition, has realized ultra-thin film deposition of inorganic materials and growth of conformal layer films by using a continuous automatic stop function. In this study, we focused on the molecular layer deposition (MLD) method that enables the deposition of thin films of organic and organic-inorganic hybrids by taking advantage of the features of ALD. By using trimethylaluminum (TMA) and ethanol (EtOH) as starting materials, we succeeded in the molecular layer deposition of thin films of organic-inorganic hybrids at room temperature, and the deposition density was improved by comparison with atomic layer deposition of TMA and water vapor.

In this study, we attempted to hyperpolarize Xe gas by spin-exchange optical pumping using a CW titanium sapphire laser of 1 W or less. We have found that the progress of hyperpolarization can be investigated by examining the nuclear magnetic resonance signal spectrum for each laser irradiation time.

As a result, under the laser conditions used this time, S/N was remarkably improved when the laser irradiation time was 30 minutes or more, and the nuclear magnetic resonance signal toword hyperpolarized Xe was obtained.

Optical constants and thin film structures of paraffin thin films were analyzed by a spectroscopic ellipsometer. As a result, it was found that the film thickness and the structure changed depending on the film forming temperature. In this experiment, the film thickness was thicker at low temperature and thinner at higher temperature. It is considered that this is because the melting point of paraffin was about 65 degrees, and therefore, when the paraffin was applied to the substrate at a low temperature by the roller, there was a part that was not completely melted, and it was thought that the paraffin was deposited thickly.

The inorganic-organic hybrid aluminum oxide thin film was coated on the inner wall of the rubidium atomic cell by the room temperature molecular layer deposition method using successive surface chemical reactions, and the relaxation time of spin polarization was improved compared with the case without coating.

Electrical impedance tomography, which visualizes the impedance distribution in a living body, is a new method for capturing tomographic images of living organisms. This has the advantages of non-exposure, small size, continuous/long time measurement. However, it is necessary to attach the electrode, and it is strongly affected by the attachment condition. On the other hand, current induced magnetic tomography (CIMT) was devised to use magnetic force to obtain impedance distribution without electrical contact. In this paper, a CIMT system was built using a current of 766.6Hz as a proof of principle. In addition, we show that the CIMT system can be used to magnetically visualize the impedance distribution.

The multichannel surface electromyography (EMG) is used to measure action potentials from the skin surface as propagation waves. We believe that anyone can make measurements and expand its use in the clinical field by making it possible to estimate the direction of myofibers when measuring with this EMG. Therefore, we investigated the relationship between the direction of the muscle fibers and the angle of the electrodes using a multichannel method that can quantitatively extract the propagating wave. From the analysis, we believe that we can estimate the direction of the muscle fibers from the propagation wave number.

The microbial administration is important in various areas. Examination for biochemical properties elucidate microbial by color. We identified the bacterium using examination for biochemical properties. As a result, the microbe was found to be Sphingomonas paucimobilis. However, the main problem is that identification probability was not indicated. We thought that it was mistake color recognition. We consider it is necessary to use L*a*b* color space in order to solve this problem.

Temporary loss of attention due to lack of sleep is one of the leading causes of illness and traffic accidents. One of the researches to prevent them is detection technology of arousal level using the skin temperature of the nose, and a thermo camera is a non-invasive device for acquiring this. However, there are some conditions and problems in detecting a specific area directly from an infrared image. In this study, a model that can detect the face and nose regions from the thermal image corresponding to the displacement of the face by machine learning was created and evaluated aiming at application to the awakening level estimation technology. The results show that the model created may be useful.

In this research Markov decision processes is applied to healthcare software. A new healthcare method which maximizes the probability of staying in objective states by dynamic programming is proposed. The effectiveness of the proposed method is shown by some computational examples.

The laser microphone with self-coupling effect of laser diode has the single-reflection laser beam, instead of the membranes. Because the laser beam works as the detection parts of the laser microphone, it has the wide and flat frequency response and the detectability under the high electromagnetic field. Single-reflection laser microphones are unable to detect spherical sound waves from a point source because of their low spatial resolution. In order to solve this problem, a multiple-reflection laser microphone employing a pair of mirrors has been developed. It was found that the frequency response of the multiple-reflection laser microphone is affected by the size of the detection area. The sensitivity is proportional to the number of reflections, which is seven times higher than the single-reflection laser microphone of the same spatial resolution. The multiple-reflection laser microphone can detect the spherical sound wave as same as the commercial 1/4 inch diameter condenser microphone.

In this paper, a new approach for image retrieval that is adaptive to user's intention is proposed. Because image content has so many interpretations to represent by a word, CBIR has been developed as a powerful tool for image retrieval. The conventional CBIR searches and sorts images where retrieved image is similar to a query input image. The retrieval works well when features of appropriate query input image are extracted. However, it is difficult to prepare the optimal feature as well as query image that corresponds to user's desired still image and/or video content.

To solve the problems, a new similarity measure using score function for multi-input query is proposed. Further, an iterative algorithm to adapt user's intention with feedback structure is implemented as user friendly interface in retrieval process. To show the effectiveness of our method, various image retrievals using mixed still image and video were executed. The precision rate was calculated to evaluate the performance of image retrieval. High performance image retrieval was achieved compared with the conventional image retrieval approach.