We propose a new fabrication method for nanofluidic device with novel shapes using thermal shadow evaporation and wet anisotropic etching in aqueous KOH solution. We also demonstrate that a single DNA molecule could be driven in the nanofluidic device by electrophoresis, in which the linear stretching and electrophoretic migration of a DNA polymer molecule could be observed at a single molecule level. Finally, we investigate length-dependent mobility of chromosome-sized DNA in nanofluidic channel and successfully separate different lengths of DNA under simultaneous action of electric field as well as pressure gradient.[This abstract is not included in the PDF]

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When a new influenza epidemic is going on, it is important to promptly plan the schedule of production and allocation of vaccines in order to mitigate the severity of the influenza. Because the production of vaccines starts after identification of the antigenic type of the spreading influenza virus, it is almost impossible to store adequate amounts of vaccines in advance. Therefore, it is necessary to timely produce and distribute the available vaccines under a daily and total limit. In this study, we formulate an optimal control problem on dynamical vaccine allocation that minimizes the number of fatalities or that of infections in an age-structured influenza epidemic model. By numerically solving this problem, we can obtain the optimal amount of vaccines allocated to each age-group on a moment-to-moment basis. We also demonstrate that the framework for optimal control of dynamical vaccine allocation is applicable to the concurrent epidemic model of seasonal and pandemic influenza.[This abstract is not included in the PDF]

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The 320-row area detector CT can provide real time in vivo information. The purpose of the present study is development of a method to estimate a material property of a blood vessel by tracking each point on the blood vessel wall from sequential ECG-gated CT images in order to determine a degree of progression of atherosclerosis as a new diagnostic indicator. In this paper, we present an image-based modeling method and software (V-Modeler).[This abstract is not included in the PDF]

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Microfabricated or microfluidic culture devices are enabling better spatiotemporal control over various signaling components (soluble factors, extracellular matrix, cell-cell contact, etc.) of cellular microenvironment which is not possible by conventional culture systems. Signaling of soluble factors is best characterized among these components owing to the ease with which they can be manipulated in the conventional cultures. Though, microfluidic devices are offering new techniques to control soluble microenvironment, and providing better insights in soluble microenvironment dependent cellular behaviors. This review will focus on some recent microfluidic devices utilized for controlling soluble microenvironment and comment on the future trend of these devices.

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We measured electrical characteristics of DNA molecular bundles of 25 micrometers in length and 50 - 1000 nm in diameter. The bundle was captured between tips of MEMS tweezers by dielectrophoresis. Two-terminal method using only tweezers failed because of contact resistance between the bundle and tips. We adopted four-terminal method which can eliminate the effect of the contact resistance. Potential probes, consisting of 2-micrometer-wide-line electrodes separated by 2 to 4 micrometers, were fabricated. The captured DNA bundle was pressed against probes and the potential drop associated with current in the bundle was measured. The conductivity of the bundle was successfully determined.[This abstract is not included in the PDF]

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In this paper, we show a microfluidic device for spatiotemporally controlled differentiation of pluripotent stem cells. In a microchannel, a distribution of a chemical concentration is spatiotemporally controllable by laminar flow, so cells seeded in the channel can be exposed to different differentiation factors depending on their positions. In the result of culturing mouse induced pluripotent stem cells in the device, undifferentiated and differentiated states were spatially controlled. Moreover, the different behavior was observed by the shift of time for exposing the cells to the specific distribution of retinoic acid. The present technique could be applied to developmental biology.

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Hydrogel-based encapsulation is one of the promising approaches for obtaining a large number of homogeneous iPS cells. In this study, we prepared three types of microcapsules by using alginate calcium hydrogel and poly-L-lysine (PLL) for immobilizing iPS cells. We found that PLL coating of the capsules was necessary for preventing cell leakage from the capsules. Moreover, we observed PLL-coated microcapsules kept undifferentiated state even in non-undiffarentiating condition.These results showed that PLL-coated microcapsules are promising for for undifferentiatied iPS cell propagation. [This abstract is not included in the PDF]

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A hydrogenase(Hase) is an enzyme that catalyzes the reversible redox reaction between hydrogen ion and hydrogen. Hase is easily inactivated under an oxygen atmosphere. The[Ni-Fe-Se]-Hase is more stabilized against oxygen molecules than the[Ni-Fe]-Hase. The former, however, has a selenocysteine nearby the active site; therefore the large-scale production is difficult by protein engineering. The calculations of the electron structures of[Ni-Fe]- and[Ni-Fe-Se]-Hases have been carried out, in order to clarify mechanism of the inactivation reaction. Consequently, not only selenocystein but also the nearest-neighbor amino acid residues on the active site have contributed to the stabilization. In other words, the[Ni-Fe]-Hase, which has no selenocystein, has possibilities to stabilize against oxygen molecule by amino acids substitution. This study will provide a new design for industrial application of Hase.

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Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) is an enzyme catalyzing carbon fixation reaction in photosynthesis with very low molecular activity. One of the effective ways of improving RuBisCO activity is the re-engineering by the mutation of amino acid residues. It is necessary for the rational re-engineering of RuBisCO to clarify the role of each amino acid residue. In this research, we carried out density functional theory calculations on the 22-residues-model around active site of RuBisCO, estimated rate-limiting step, and found 3 important amino acid residues that can greatly influence the reaction.

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In this study, we investigated types and motives of drink intakes based on the situations thorough behavioral records and interviews as a preliminary step for an ethnography survey. Some subjects actively selected to consume drinks because of their availability or compatibility with the situations, whereas other often had no alternative but to consume drinks that were provided. Drinks rather than water were preferentially consumed during meals at their home, while coffee were consumed during meals at workplaces. The test subjects did not consume bottled water but bottled tea and milk as an alternative for tap water or water filtered with water purifiers. [This abstract is not included in the PDF]

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