Potentials recorded from neck and supraclavicular fossa during a rapid voluntary contraction of the triceps brachii muscle.

Two experiments were performed in order to study whether it is possible to record potentials related to the voluntary movement from electrodes placed on the skin overlying the spinous process of the 2nd and 6th cervical vertebrae and at Erb's point ipsilateral to the movement. In the first series of experiments (Experiment I) the subject initiated spontaneously an arm movement accompanying a contraction of the right triceps brachii muscle. Rapid extension of the right 5 fingers was also performed self paced.

Studies on chitosan: 4. Lysozymic hydrolysis of partially N-acetylated chitosans.

The lysozymic digestibility of partially N-acetylated chitosans was studied by measuring the reducing sugars produced and the molecular weights of their hydrolysates. Moderately N-deacetylated chitosans (MDC), obtained by N-deacetylation of chitin under heterogeneous conditions, were about four times more digestible at an early stage than partially N-acetylated chitosans (PAC-H) with similar acetyl content, prepared by N-acetylation of highly N-deacetylated chitosans under homogeneous conditions. The molecular weights of the hydrolysates of MDC decreased rapidly but gradually reached a constant value in contrast to the behaviour of PAC-H.

Accommodation on downward gaze.

A study was conducted with the purpose of examining the possible effects of vertical and horizontal eye movements upon accommodation. A special Badal stimulator was made which was vertically rotatable around the center of an eye. The stimulator was attached to the Three-Dimensional Optometer III (TDOIII), which could measure accommodation, eye movement, and pupil diameter simultaneously.

The influence of combined visual and tactile information on finger and eye movements during shape tracing.

Adaptation experiments in shape tracing were conducted to investigate finger and eye movements in various conditions of visual and tactile information. Maximum velocity, mean velocity, maximum acceleration and reacceleration point were calculated from finger movements. Number of eye fixations and lead time of eye fixation to finger position were calculated from eye movements.

Studies on carbohydrate-binding proteins using liposome-based systems--I. Preparation of neoglycoprotein-conjugated liposomes and the feasibility of their use as drug-targeting devices.

1. Five types of neoglycoprotein-coupled liposomes were prepared in order to investigate their potential utility as new types of drug-targeting devices which exploit cellular functions of carbohydrate-binding proteins. 2.

Recruitment threshold and muscle fiber conduction velocity of single motor units.

The average muscle fiber conduction velocity (CV) measured with multicontact surface electrodes has been reported to increase with the contraction force. To understand this behavior better, we studied the relationship between the recruitment threshold and the muscle fiber CV of single motor units (MUs). Myoelectric signals were recorded simultaneously with a linear surface electrode array and a selective needle electrode.

Distribution of innervation zones in the human biceps brachii.

Two types of multicontact surface electrodes were used to define the distribution of innervation zones (motor end-plate regions) in human skeletal muscles: a linear array electrode and a two-dimensional grid electrode. These electrodes detected motor unit action potentials (MUAPs) propagating along the muscle fibers during a voluntary contraction and marked the source of the propagation, which was assumed to indicate the position of the innervation zones. The linear array electrode defined the absolute position of the innervation zones in the muscle, but it could not clarify the detailed distribution, within the innervation zones.

Studies on chitosan: 3. Evidence for the presence of random and block copolymer structures in partially N-acetylated chitosans.

The chemical structures of moderately N-deacetylated chitosans (MDC) derived from chitin under heterogeneous reaction conditions and partially N-acetylated chitosans (PAC) derived from highly N-deacetylated chitosans (HDC) under homogeneous reaction conditions were deduced from the data of the stability of their solutions in alkaline media, the swelling behaviour and X-ray diffraction patterns of their films in connection with the degree of N-acetylation of them. The solutions of PAC with more than 51% acetyl content, which were prepared from HDC by N-acetylation, were stable and remained clear and homogeneous by adding 1.2 equivalents of NaOH.

Technique for detecting MUAP propagation from high-threshold motor units.

A technique was developed to identify the propagation pattern of high-threshold motor unit action potentials (MUAPs) in human skeletal muscles. A linear surface array and a selective needle electrode were used simultaneously for detection of myoelectric signals during a constant-force isometric voluntary contraction. The needle signals were decomposed into trains of single MUAPs and were used to trigger-average the surface signals.

Effect of orientation on visual and vibrotactile letter identification.

The effect of stimulus orientation of letters presented either visually or vibrotactually was examined to obtain basic information on sensory substitution using the tactile sense. The reaction time (RT) to identify the letters F and R presented in normal or mirror-image form at four orientations each was measured. In addition, conditions of 0 degree and 270 degrees of head rotation from vertical and arm rotation from the midline axis were employed.

Physico-chemical properties of silk fibroin membrane as a biomaterial.

A water-insoluble silk fibroin membrane was prepared by immersing a silk fibroin membrane as cast in 50 vol% aqueous methanol solution for different periods of time at 25 degrees C. To use the membrane as a biomaterial, oxygen and water vapour permeability, transparency, mechanical property and enzymatic degradation behaviour in vitro of the membrane in the wet state were investigated. These physico-chemical properties changed according to the condition of the methanol treatment.

Dynamic eye accommodation evoked by apparent distances.

A three-dimensional optometer (TDO), which can measure simultaneously three major ocular functions in a working environment, was used to measure the visual responses of human subjects viewing: (1) actual artworks and (2) corrugation presented by moving random dots on a cathode ray tube (CRT). Measurements were performed in natural viewing conditions on two emmetropic females. Both subjects demonstrated distinct accommodative responses for the stimuli presented at a fixed distance.

Studies on chitosan: 2. Solution stability and reactivity of partially N-acetylated chitosan derivatives in aqueous media.

The stability of the solutions of partially N-acetylated chitosans was studied by two methods: (1) 1% solutions of the chitosan derivatives in 0.1 M aqueous acetic acid were added dropwise to buffer solutions with pH from 8.6 to 12 and to a 0.

The interaction of cultured cells with membranes composed of random and block copolypeptides.

Random copolypeptides and block copolypeptides were synthesized, and an interaction between these polypeptide membranes and the cells was studied by a cell culture method (cell line, Ca. 9.22).

Microprocessor-based hearing aid for the deaf.

A speech reception aid that converts speech into text by use of a microprocessor has been developed for profoundly deaf people. The present system automatically recognizes a spoken word and presents the corresponding text visually and tactually. The system, however, restricts the acceptable number of words and speakers.

Processing of myoelectric signals for estimating the location of innervation zones in the skeletal muscles.

An electrical activity associated with the excitement of muscle fibers arises from the myoneural junctions located at the middle length of the fibers and propagates to the both ends. This propagation can be detected with a multi-electrode array placed on the skin surface. Therefore, the position of the myoneural junctions, or of the innervation zones as a collection of myoneural junctions, can be estimated from the source of the propagation.

Fibre conduction velocity and fibre composition in human vastus lateralis.

The relationship between muscle fibre composition and fibre conduction velocity was investigated in 19 male track athletes, 12 sprinters and 7 distance runners, aged 20-24 years, using needle biopsy samples from vastus lateralis. Cross sectional areas of the fast twitch (FT) and slow twitch (ST) fibres were determined by histochemical analysis. The percentage of FT fibre areas ranged from 22.

Covalent immobilization of chitosan derivatives onto polymeric film surfaces with the use of a photosensitive hetero-bifunctional crosslinking reagent.

Partially N-acetylated chitosan was covalently immobilized onto polymeric film surfaces using the photosensitive hetero-bifunctional crosslinking reagent, methyl 4-azidobenzoimidate, which was previously attached to the chitosan by the reaction between an imidoester group of the reagent and a free amino group of the chitosan. The grafting was accomplished by irradiating with ultraviolet light the modified chitosan being coated on the film surfaces to photolysis arylazide groups, thus crosslinking the chitosan and the underlying substrate polymer together. For ultraviolet absorption and infrared spectroscopy, the irradiation time of 3 min was found to be sufficient for the photolysis of the azide group.

Changes of the average muscle fiber conduction velocity during a varying force contraction.

The average conduction velocity of muscle fibers measured with a surface electrode has been reported to increase with the level of contraction force. To clarify the factors causing this increase, the authors decomposed the interference surface EMG signal into its constituent motor unit action potentials and compared the average conduction velocity with the conduction velocity measured at the individual discharges of motor units. The conduction velocity within individual motor units increased with the contraction force and contributed to the increase of the average conduction velocity.

Skeletal muscles from which the propagation of motor unit action potentials is detectable with a surface electrode array.

Motor unit action potentials (MUAPs) propagate bidirectionally along the muscle fibers. Whether or not the propagation of MUAPs can be detected with surface electrodes depends on the configuration of muscle fibers and innervation zones. The authors clarified the muscles from which the propagation of MUAPs is detectable with a surface electrode array placed along the muscle fibers.

Temporal relationships of EMG changes preceding voluntary movement to premovement cortical potential shifts.

The silent period and a rhythmic slower wave in EMG appear preceding a rapid voluntary movement (Tanii 1984). The present study was performed to investigate temporal relationships of the EMG changes preceding movement to premovement cortical potential shifts, in order to clarify whether the EMG changes are related to preparation and initiation of voluntary movement. A strong push of a hard band with the right wrist was conducted rapidly following a slightly sustained contraction.

[Psychological studies on accommodation of the eye].

Psychological studies on accommodation are reviewed on the following subjects: (1) subjective and objective methods of measuring accommodation, and their related practical problems in visual experiments, (2) accommodative responses in the absence of an adequate visual stimulus (a resting point of accommodation or a dark focus), and the specific phenomena of night myopia, empty myopia and instrument myopia, (3) contribution of accommodation to the perception of depth and the influence of imagination or thinking of distance on accommodation, (4) unsettled problems on accommodation in the three domains of myopia mentioned above, and the prospect of research in the future, and (5) a description of the results of psychological studies on accommodation that are applied to the establishment of an optimal condition of visual environment.