Biomedical subjects

M Mochimaru

Publications and source records attributed to M Mochimaru.

8 recordsLinked to original sources

PubMed2002

Disruption of the uptake hydrogenase gene, but not of the bidirectional hydrogenase gene, leads to enhanced photobiological hydrogen production by the nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120.

In order to determine the effects of the deletion of hydrogenase genes on nitrogenase-based photobiological H(2) productivity by heterocystous N(2)-fixing cyanobacteria, we have constructed three hydrogenase mutants from Anabaena sp. PCC 7120: hupL(-) (deficient in the uptake hydrogenase), hoxH(-) (deficient in the bidirectional hydrogenase), and hupL(-)/ hoxH(-) (deficient in both genes). The hupL(-) mutant produced H(2) at a rate four to seven times that of the wild-type under optimal conditions. The hoxH(-) mutant produced significantly lower amounts of H(2) and had slightly lower nitrogenase activity than wild-type. H(2) production by the hupL(-)/ hoxH(-) mutant was slightly lower than, but almost equal to, that of the hupL(-) mutant. The efficiency of light energy conversion to H(2) by the hupL(-) mutant at its highest H(2) production stage was 1.2% at an actinic visible light intensity of 10 W/m(2) (PAR) under argon atmosphere. These results indicate that deletion of the hupL gene could be employed as a source for further improvement of H(2) production in a nitrogenase-based photobiological H(2) production system.

Anabaena↗

PubMed2000

Analysis of 3-D human foot forms using the Free Form Deformation method and its application in grading shoe lasts.

An effective way to design well-fitting products is to analyse human body forms and to classify them into several groups. In the present study, a new method is proposed to analyse human body forms using the FFD (Free Form Deformation) technique. The FFD method is a way to deform the shapes of object smoothly by moving control lattice points set around the object. The reference body form is automatically deformed to coincide with the other body forms using the FFD method. The dissimilarity is defined by the movements of the control lattice points. The foot forms of 56 Japanese adult females were analysed with this method, and distributions for them were calculated using multi-dimensional scaling. The first axis contrasts feet with high dorsal arches and low dorsal arches, and the second axis is related to the antero-posterior proportion of the foot. As an application of the present method, a last of width EEEE was designed from an existing last of width E by applying the control lattice points that converted a representative foot of width E into a foot of width EEEE. The new EEEE width last reflected the allometric differences between narrow and wide feet better than one obtained by a conventional method. It was found that the present method with FFD is not only useful for classifying 3-D human body forms, but also has potential as applications for designing well-fitting products.

Adult↗

PubMed1999

Real-time 3-D model-based navigation system for endoscopic paranasal sinus surgery.

This paper presents a three-dimensional (3-D)-model-based navigation system for endoscopic sinus surgery treating paranasal sinusitis. Endoscopic surgery is becoming more common because of its low invasiveness. Its problem with disorientation, however, is one of the toughest barriers for the novice and may lead even an expert to commit serious surgical errors, e.g., causing cerebrospinal fluid (CSF) leakage or blinding the patient. To prevent such complications and optimize training, our system aids in navigation by showing a single perspective view of the patient and the endoscope models. This virtual endoscope has a viewing cone with a simulated light to indicate the viewing direction and visual field in real-time. The system's three clipping planes automatically follow the endoscope and help keep the surgeon aware of the endoscope's actual position. An experiment comparing the system to conventional navigation using a triplanar display showed that the perspective view was referenced very frequently, giving a positive impressions, while the triplanar display was almost completely ignored, apparently because it was too difficult to interpret immediately.

Adult↗

PubMed1999

Interobserver errors in anthropometry.

To present basic information on the interobserver precision and accuracy of 32 selected anthropometric measurement items, six observers measured each of 37 subjects once in two days. The data were analyzed by using ANOVA, and mean absolute bias, standard deviation of bias, and mean absolute bias in standard deviation unit were used as measures of bias. By comparing the results of the two days, the effects of the practice on measurement errors were also investigated. Variance was overestimated by more than 10% in five measurements. Interobserver error variance and random error variance were highly correlated with each other. Measures of the bias were significantly correlated with interobserver and especially with random error variances. The interobserver errors were drastically reduced on the second day in the measurement items in which the causes of the interobserver errors could be specified. It was speculated that even when the definitions of the landmarks and measurement items were clear, the ambiguity in the practical procedures in locating landmarks, applying instruments, and so on, permitted each observer to develop his or her own measurement technique, and it in turn caused interobserver errors. To minimize interobserver and random errors, the standardization of measurement technique should be extended to the details of the practical procedures.

Adult↗

PubMed1997

Three kinds of binding site for tentoxin on isolated chloroplast coupling factor 1.

Tentoxin binding on chloroplast coupling factor 1 (CF1) was studied using a centrifugation column method followed by HPLC analysis. From non-linear regression analysis of the results, the presence of three types of binding site with the following Kd values was deduced: 6.9x10(-8) M (first site), 1.4x10(-5) M (second site), and 6.3x10(-3) M (third site). The binding of one tentoxin inhibits, that of two tentoxins moderately restores, and that of three tentoxins greatly stimulates the ATPase activity of CF1. The forward rate constant of the binding of tentoxin on the first site was 6.3x10(3) M-1 s-1.

Binding Sites↗

PubMed1997

Automatic calculation of the medial axis of foot outline and its flexion angles.

As one of the morphological characteristics of human foot, flexion angles of medial axis of foot outline have been proposed in order to improve shoe comfort. Foot outlines were easily obtained by a scriber, whereas calculation of the medial axis and its flexion angles from the foot outline had inter-operator errors and a lack of reproducibility. This is because foot outlines were inputted by a digitizer, and flexion points of the medial axis were determined by eye inspection. An automatic method of calculation was developed for the following purposes: (1) to decrease inter-operator errors caused by manual operation; (2) to improve the reproducibility of the medial axis and its flexion angles; and (3) to save time and trouble in processing a large amount of data. The flexion angle reproducibility of the present method was within 1 degree. The errors in the flexion angles determined by the present method are half those determined by the conventional method. The flexion angles of over 5000 foot outlines that were obtained in 1987 were calculated when the present method was developed. The mean posterior flexion angle of the adults was 8.4 degrees. Since the majority of Japanese feet are outflared, this characteristic should not be ignored in designing/modifying shoe lasts.

Adult↗

PubMed1996

Random errors in anthropometry.

In order to present basic information on the magnitude of and variance due to the random error in anthropometry, 219 measurement items were taken on 12 subjects twice by the same observer. The precision (i.e., consistency between the repeated measurements) was investigated for these measurement items. The reliability was quantified using mean absolute difference (MAD), technical error of measurement (TEM), and reliability coefficient (R). MAD and TEM are highly correlated with each other and both represent the magnitude of error. They are not correlated with R, which represents the proportion of error-free variance. Larger measurements tend to have absolutely larger but relatively smaller random errors and higher reliability in the size range of 1-10 cm. Imprecision is inherent in anthropometry of the living because of the fact that the human body is not rigid. This may be responsible for the above tendency. Relatively large MAD and low R may be due to small absolute size, landmarks difficult to locate precisely, soft tissue deformation, and the inconsistency of the posture of the subject.

Adult↗

PubMed1994

The three-dimensional measurement of unconstrained motion using a model-matching method.

The measurement of motion is a basic technique for the quantitative mechanical analysis of human movement. However, previous methods of motion measurement using goniometry and surface markers have several associated problems: goniometers constrain human motion; and surface markers are missed, etc. To resolve these problems, a new technique of motion measurement using image processing is proposed. In this method, movements of the whole body are captured as image information, and a geometric model of a human body is fitted onto the contours of the image sequences. The joint angles are then estimated from the model. Usually, every segment has to be coloured separately so as to fit the geometric model automatically into the images; furthermore, this takes a very long time to process. Therefore, we reduced the processing time using the information in the overlap area between the models and images, instead of contour information. We estimated the joint angles of hidden segments with the grey scale image information. Thus there is no need to colour segments and attach surface markers; and unconstrained motion can be measured. Using the method developed, three-dimensional motion of the fingers including 21 segments was measured in 3-5 min per frame by a personal computer. The errors are 2 degrees maximally.

Ergometry↗