Polynomial-Time Algorithm for Controllability Test of a Class of Boolean Biological Networks

<p/> <p>In recent years, Boolean-network-model-based approaches to dynamical analysis of complex biological networks such as gene regulatory networks have been extensively studied. One of the fundamental problems in control theory of such networks is the problem of determining whether a given substance quantity can be arbitrarily controlled by operating the other substance quantities, which we call the controllability problem. This paper proposes a polynomial-time algorithm for solving this problem. Although the algorithm is based on a sufficient condition for controllability, it is easily computable for a wider class of large-scale biological networks compared with the existing approaches. A key to this success in our approach is to give up computing Boolean operations in a rigorous way and to exploit an adjacency matrix of a directed graph induced by a Boolean network. By applying the proposed approach to a neurotransmitter signaling pathway, it is shown that it is effective.</p

Longitudinal Variation in Physical Chracteristics and Macroinvertebrate Communities of Riffles in Toyo River, Japan

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

High-performance microchannel emulsification device with microfabricated asymmetric through-holes

High-performance microchannel emulsification device with microfabricated asymmetric through-hole

Environmental Conditions and the Distribution of Benthic Macroinvertebrates in the Estuary of the Toyo River, Japan

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

CFD analysis of microchannel emulsification: Droplet generation process and size effect of asymmetric straight flow-through microchannels

Asymmetric straight flow-through microchannel (MC) arrays are high-performance MC emulsification devices for stable mass production of uniform droplets. This paper presents computational fluid dynamics (CFD) simulation and analysis of the generation of soybean oil-in-water emulsion droplets via asymmetric straight flow-through MCs, each consisting of a microslot and a narrow MC. We also used CFD to investigate the effects of the channel size and the flow of the dispersed phase on MC emulsification using asymmetric straight flow-through MCs with a characteristic channel size of 5 to 400 μm. The overall shape of an oil-water interface and the time scale during droplet generation via a control asymmetric straight flow-through MC were appropriately simulated. Better insight was obtained on the flow profile of the two phases and the internal pressure balance of the dispersed phase during droplet generation. Comparison of the CFD and experiment results also provided insight into dynamic interfacial tension during droplet generation. Successful droplet generation was observed below a critical dispersed-phase velocity. In this case, the resultant droplet size was proportional to the channel size and was not sensitive to the dispersed-phase velocity applied. The maximum droplet generation rate per channel was inversely proportional to the channel size, unless the buoyancy force did not promote droplet detachment. The maximum droplet productivity per unit area of an asymmetric straight flow-through MC array was estimated to be constant, regardless of channel size

High-performance production of monodisperse emulsions using microfabricated asymmetric through-hole array

This paper reports high-performance production of monodisperse emulsions using numerous asymmetric through holes microfabricated on a silicon chip. Monodisperse oil-in-water (O/W) emulsions with droplet sizes of approximately 30 µm were stably produced via asymmetric through holes at high droplet generation rates up to several hundreds of thousands per second. This paper also reports three-dimensional simulation of emulsion droplet generation via an asymmetric through hole using a computational fluid dynamics (CFD) method. The calculation results showed an excellent agreement with the experimental results and provided a better understanding of the droplet generation process

Experimental and computational studies of generation of highly uniform droplets via asymmetric microchannels

Experimental and computational studies of generation of highly uniform droplets via asymmetric microchannel