Hiroki Kobayashi

Phase-field model for solidification of ternary alloys coupled with thermodynamic database

Abstract A phase-field model coupled to real thermodynamic data in which the vanishing kinetic coefficient condition is proposed. The validity of the model is examined by comparing the calculated result of the equilibrium state with theoretical predictions for both one and two-dimensional simulations. Numerical simulations of micro-segregation and isothermal dendrite growth is presented to demonstrate the effectiveness of the model.

Six1 and Six4 are essential for Gdnf expression in the metanephric mesenchyme and ureteric bud formation, while Six1 deficiency alone causes mesonephric-tubule defects

Interaction between the ureteric-bud epithelium and the metanephric mesenchyme is important for kidney development. Six1 and Six4 are the mammalian homologs of Drosophila sine oculis, and they are coexpressed in the nephrogenic mesenchyme. Six1-deficient mice show varying kidney defects, while Six4-deficient mice have no apparent abnormalities. Here, we report Six1/Six4-deficient mice that we generated in order to elucidate the functions of Six4 in Six1-deficient kidney development. The Six1/Six4-deficient mice exhibited more severe kidney phenotypes than the Six1-deficient mice; kidney and ureter agenesis was observed in all the neonates examined. The Six1/Six4-deficient metanephric mesenchyme cells were directed toward kidney lineage but failed to express Pax2, Pax8, or Gdnf, whereas the expression of these genes was partially reduced or unchanged in the case of Six1 deficiency. Thus, Six4 cooperates with Six1 in the metanephric mesenchyme to regulate the level of Gdnf expression; this could explain the absence of the ureteric bud in the Six1/Six4-deficient mice. In contrast, Six1 deficiency alone caused defects in mesonephric-tubule formation, and these defects were not exacerbated in the Six1/Six4-deficient mesonephros. These results highlight the fact that Six1 and Six4 have collaborative functions in the metanephros but not in the mesonephros.

Identification and characterization of a novel Dvl‐binding protein that suppresses Wnt signalling pathway

Background:   Dvl is a cytoplasmic protein to regulate the stability of β‐catenin in the Wnt signalling pathway. However, the molecular mechanism by which Dvl regulates the Wnt signalling pathway is not fully understood.

Homeoproteins Six1 and Six4 regulate male sex determination and mouse gonadal development

The Y-linked gene Sry regulates mammalian sex determination in bipotential embryonic gonads. Here, we report that the transcription factors Six1 and Six4 are required for male gonadal differentiation. Loss of Six1 and Six4 together, but neither alone, resulted in a male-to-female sex-reversal phenotype in XY mutant gonads accompanied by a failure in Sry activation. Decreased gonadal precursor cell formation at the onset of Sry expression and a gonadal size reduction in both sexes were also found in mutant embryos. Forced Sry transgene expression in XY mutant gonads rescued testicular development but not the initial disruption to precursor growth. Furthermore, we identified two downstream targets of Six1/Six4 in gonadal development, Fog2 (Zfpm2) and Nr5a1 (Ad4BP/Sf1). These two distinct Six1/Six4-regulated pathways are considered to be crucial for gonadal development. The regulation of Fog2 induces Sry expression in male sex determination, and the regulation of Nr5a1 in gonadal precursor formation determines gonadal size.

Novel Daple-like protein positively regulates both the Wnt/β-catenin pathway and the Wnt/JNK pathway in Xenopus

Wnt signaling pathways are essential in various developmental processes including differentiation, proliferation, cell migration, and cell polarity. Wnt proteins execute their multiple functions by activating distinct intracellular signaling cascades, although the mechanisms underlying this activation are not fully understood. We identified a novel Daple-like protein in Xenopus and named it xDal (Xenopus Daple-like). As with Daple, xDal contains several leucine zipper-like regions (LZLs) and a putative PDZ domain-binding motif, and can interact directly with the dishevelled protein. In contrast to mDaple, injection of xDal mRNA into the dorso-vegetal blastomere does not induce ventralization and acted synergistically with xdsh in secondary axis induction. XDal also induced expression of siamois and xnr-3, suggesting that XDal functions as a positive regulator of the Wnt/beta-catenin pathway. Injection of xDal mRNA into the dorso-animal blastomere, however, induced gastrulation-defective phenotypes in a dose-dependent manner. In addition, xDal inhibited activin-induced elongation of animal caps and enhanced c-jun phosphorylation. Based on these findings, xDal is also thought to function in the Wnt/JNK pathway. Moreover, functional domain analysis with several deletion mutants indicated that xDal requires both a putative PDZ domain-binding motif and at least one LZL for its activity. These findings with xDal will provide new information on the Wnt signaling pathways.

Wearable forest clothing system: beyond human-computer interaction

Wearable Forest is a garment that bioacoustically interacts with distant wildlife in a remote forest through a networked remote-controlled speaker and microphone. it expresses the unique bioacoustic beauty of nature and allows users to interact with a forest in real time through a network to acoustically experience a distant forest soundscape, thus merging humans and nature without great environmental impact. This novel interactive sound system can create a sense of unity between users and a remote soundscape, enabling users to feel a sense of belonging to nature even in the midst of a city. This paper describes the theory of interaction between the Human and the Biosphere through the design process of the Wearable Forest concept.

Wearable forest: feeling of belonging to nature

Smoke Water Fire is a digital animation of a deforming blob of fluid that has been slowed down and stripped of environmental context in order to explore the shape of ephemeral media. The animation addresses several interrelated themes: context and speed, commonality of the equations of physics, and ephemerality of fluid media. It does this through its use of scale-free computational fluid physics, abstract digital representations, and projected moving pictures. Because of its purely computational nature, Smoke Water Fire removes any context of material or physical scale and leaves the viewer with little more than the dynamics of the shape itself. mark Stock

Healthiness from Duality

Healthiness is a good old question in program logics that dates back to Dijkstra. It asks for an intrinsic characterization of those predicate transformers which arise as the (backward) interpretation of a certain class of programs. There are several results known for healthiness conditions: for deterministic programs, nondeterministic ones, probabilistic ones, etc. Building upon our previous works on so-called state-and-effect triangles, we contribute a unified categorical framework for investigating healthiness conditions. This framework is based on a dual adjunction induced by a dualizing object and on our notion of relative Eilenberg-Moore algebra. The latter notion seems interesting in its own right in the context of monads, Lawvere theories and enriched categories.Categories and Subject Descriptors F.3.2 [Semantics of Programming Languages]: Algebraic Approaches to Semantics

HCI Interventions for Monitoring Environmental Health

For this demonstration, Dr. Hill H. Kobayashi will present a collection of HCI interventions designed to monitor radiation levels in the exclusion zone around the Fukushima Daiichi Nuclear Power Plant in Japan. CHI2018 conference attendees will view design artifacts, listen to audio and read posters documenting the latest studies conducted by the Kobayashi Lab at the University of Tokyo. Our goal is to promote dialogue around a relatively new discipline called Human Computer Biosphere Interaction (HCBI), and explore the boundaries of this discipline with the CHI community.