Abstract: The conversion of chemical energy into mechanical forces that powers cell movements is
a ubiquitous theme across biology. Besides molecular motors such as kinesin-microtubule and
actin-myosin complexes, biological springs and ratchets can also store and release energy to rectify
motion. The acrosome reaction of horseshoe crab sperm is a simple example of a biological spring
where a 60!μm-long crystalline bundle of actin filaments, tightly cross-linked by actin bundling
protein scruin, straightens from a coiled conformation and extends from the cell to penetrate an egg
in about five seconds. To identify the basis and mechanism for this movement, we examine the
possible sources of chemical and mechanical energy and show that the stored elastic energy alone is
sufficient to drive the reaction. We also provide an estimate of the maximum force generated during
the uncoiling by stalling the bundle using an agarose gel to show the reaction produces enough
force to penetrate the egg.
Abstract: In generally, it is known that structures of living thing are optimized. The wings of a
dragonfly are thin and light. Although it is having the structure of bearing the load produced in the
case of an advanced flight such as “Flapping flight”, “Glide”, and “Hovering”. The wings of a
dragonfly are made by veins and membranes. In addition, the wings of a dragonfly have some
characteristic structures, such as “Nodus”. Thus, the wings of dragonfly have many complicated
structures. The configuration of costal vein of the wings is different from them of other insects. So,
we paid attention to the configuration of costal vein of the wings. Therefore, in this study, we
researched about the effect of costal vein. As a result, it was showed that the configuration of costal
vein became bending and torsional deformation small. In addition, it was showed that the
configuration of costal vein related to nodus. In this study, several 3-D models of the dragonfly’s
wing were made and calculated by the 3-D finite element method.
Abstract: This paper concerns a mechanics of interactions of helical structures in proteins. Helices
are the most important secondary structures of proteins and contribute the formation of a more
complex 3-D structure, and so the analysis of interactions of helices is quite critical. We examine
1290 protein structures that have 2.0 Å or better resolutions and less than 20 percent of their
sequences in common. Interactions between helices are represented by two parameters: the distance
and angle. Assuming that helices are slender rigid rods with finite length, we define three different
mechanisms of interactions: (1) line-on-line contact; (2) endpoint-to-line contact; and (3) endpointto-
endpoint contact. In this paper, interactions for the first case are expressed with the 3-D relative
rigid-body motion (position and orientation) and the unique volume element for correctly
integrating over rigid-body motions are determined using six parameters. The results are extremely
useful for the correct analysis of interactions in terms of distance and angle without the statistical
biases inherent in the three data sets.
Abstract: The inner ear hair cells, the receptors sensing mechanical stimuli such as acoustic
vibration and acceleration, achieve remarkably high sensitivity to miniscule stimuli by selectively
amplifying small inputs. The gating springs hypothesis proposes that a phenomenon called negative
stiffness is responsible for the nonlinear sensitivity. According to the hypothesis, the bundle
becomes more sensitive in certain region as its stiffness changes due to the opening or closing of
transduction channels, which in turn exert force in the same direction of the bundle’s displacement.
In this study, we developed a conceptual model of an inertial sensor inspired by the inner ear hair
cells, focusing on the hair cell’s amplifying mechanism known as negative stiffness. The negative
stiffness was applied to a simple mass-spring-damper system with nonlinear spring derived from
gating springs hypothesis. Sinusoidal stimuli of 0.1Hz~10Hz with magnitude of 1pN to 1000pN
were applied to the system to match the dynamic range of vestibular organs. Simulation on this
nonlinear model was performed on MATLAB, and power transfers and sensitivities in both
transient and steady states were obtained and compared with those from the system with linear
spring. Parameters were chosen in relation to those of the hair bundle to reproduce operating
conditions of both the hair cells and micro inertial sensors. The suggested model displayed
compressive nonlinear sensitivity resulting from selective amplification of smaller stimuli despite
the energy loss due to large viscous damping typical in micro systems.
Abstract: This study focused on the treatment performance of membrane bioreactor (MBR)
coupled with intermittent ozone bubbling for the effective recovery of dissolved organics from
coagulated fresh sewage sludge. Intermittent ozone bubbling was effective in the prevention of
permeation resistance increase caused by particle accumulation on membrane surface, which result
in keeping high permeation flux. MBR with intermittent ozone bubbling is believed to be an
effective system for the recovery of organic matter usefully utilized in biological denitrification as
well as membrane fouling reduction.
Abstract: In this work a method to characterize soft tissue properties for mechanical modeling is
presented. Attention is especially focused on developing a model of the lower esophagus to be used
in a surgical simulation, which shows a promise as a training method for medical personnel. The
viscoelastic properties of the lower esophageal junction are characterized using data from animal
experiments and an inverse FE parameter estimation algorithm. Utilizing the assumptions of quasilinear-
viscoelastic theory, the viscoelastic and hyperelastic material parameters are estimated to
provide a physically based simulation of tissue deformations in real time. To calibrate the
parameters to the experimental results, a three dimensional FE model that simulates the forces at the
indenter and an optimization program that updates new parameters and runs the simulation
iteratively are developed. It was possible to reduce the time and computation resources by
decoupling the viscoelastic part and elastic part in a tissue model. The comparison of the simulation
and the experimental behavior of pig esophagus are presented to provide validity to the tissue model
using the proposed approach.
Abstract: This paper presents a microbiochip which can detect an antigen-antibody reaction
through an electrical signal in real time with high sensitivity and low sample volume by using
nanogold particle and silver enhancement. A filtration method using the microbead is adopted for
sample immobilization. The chip is composed of an inexpensive and biocompatible
Polydimethylsiloxane (PDMS) layer and Pyrex glass substrate. Platinum microelectrodes for
electric signal detection were fabricated on the substrate and microchannel and pillar-type
microfilters were formed in the PDMS layer. Successively introducing polystyrene microbeads
precoated with protein A, anti-protein A (which was the first antibody) and the second antibody
conjugated with nanogold particles into the microchannel, the resulting antigen-antibody complex
was fixed on the bead surface. The injection of silver enhancer increased the size of nanogold
particles tagged with the second antibody. As a result, microbeads were connected to each other and
formed an electrical bridge between microelectrodes. Resistance measured through the electrodes
showed a difference of two orders of magnitude between specific and nonspecific immunoreactions.
The developed immunoassay chip reduced the time necessary for an antigen-antibody
reaction to 10 min, thus shortening the overall analysis time from 3 hours to 50 min. The
immunoassay chip reduces analysis time for clinical diagnoses, is simple, and has high sensitivity.
Abstract: Most ultrasound diagnosing systems for osteoporosis lack diagnostic precision due to the
measurement of specific regions of interest (ROI). As well as using the existing ROI measurement
method, this study introduced the concept of analyzing the distribution patterns of bone quality.
Linear scanning and ultrasound transmission techniques were used to obtain the broadband
ultrasound attenuation (BUA) images of the calcaneus. A 13mm-diameter ROI was selected as the
position of minimum BUA value locally in the posterior calcaneus. Mean values of BUA and speed
of sound (SOS) at the ROI, as well as the osteoporosis index (OI), by their linear combination, were
defined. For a more accurate diagnosis of osteoporosis, OI and images of the bone quality
distribution of the calcaneus were utilized together. The calcaneus is inhomogeneous and,
furthermore, its images are not perpendicular to the direction of the ultrasound beam. Hence, the
mean values of BUA and SOS for the entire calcaneus do not have any significant meaning.
Accordingly, four image patterns of other OI in the calcaneus were defined in order to increase the
correlation between diagnostic parameter and age. The results revealed a higher correlation between
the bone quality index and age (r=0.75, p<0.0001), for which the pattern index was reflected on OI,
than that (r=0.65, p<0.0001) of OI merely at ROI. This result confirmed the possibility of a new
osteoporosis diagnostic method using the BUA distribution images of the entire calcaneus.
Abstract: Melt processable plasticized cellulose diacetate (CDA) was prepared using triacetin (TA) as a
plasticizer and its mechanical properties were characterized. The processability of the plasticized CDA
was further enhanced by using a small amount of epoxidized soybean oil as a secondary plasticizer.
The glass transition temperature of the plasticized CDA was observed at 50°C lower than that of the
virgin CDA and the incorporation of 5 % of ESO also resulted in an additional 20°C decrease in the
Tg value. In order to obtain practical processing conditions, a plasticizer content of more than 20
wt % should be used.
Abstract: In this study, the change of the natural frequencies in mouse femurs with osteoporosis
was investigated based on a vibration test and a finite element. Three groups of the femurs include
the osteoporotic group, the treated group and the normal group. In the vibration test, the natural
frequencies were measured by the mobility test. For the finite element analysis, the micro finite
element model of the femur was reconstructed using the Micro-CT images and the Voxel mesh
generation algorithm. From the results, the averaged natural frequencies in the osteoporotic group
were the highest, followed by those in the treated group. The finite element models were validated
within 15% errors by comparing the natural frequencies in the finite element analysis with those in
the vibration test. The developed Micro-CT system, the Voxel mesh generation algorithm, the
presented finite element analysis, and vibration test could be useful for the investigation of the
structural change of the bone tissue, and the diagnosis and the treatment in the osteoporosis.