2,517 results match your criteria: "Graduate School of Information Science[Affiliation]"

Emergence of integrated behaviors through direct optimization for homeostasis.

Neural Netw

September 2024

Graduate School of Information Science and Technology, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.

Homeostasis is a self-regulatory process, wherein an organism maintains a specific internal physiological state. Homeostatic reinforcement learning (RL) is a framework recently proposed in computational neuroscience to explain animal behavior. Homeostatic RL organizes the behaviors of autonomous embodied agents according to the demands of the internal dynamics of their bodies, coupled with the external environment.

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Dynamic mode (DM) decomposition decomposes spatiotemporal signals into basic oscillatory components (DMs). DMs can improve the accuracy of neural decoding when used with the nonlinear Grassmann kernel, compared to conventional power features. However, such kernel-based machine learning algorithms have three limitations: large computational time preventing real-time application, incompatibility with non-kernel algorithms, and low interpretability.

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An encompassed representation of timescale hierarchies in first-order reaction network.

Proc Natl Acad Sci U S A

May 2024

The Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo 001-0021, Japan.

Complex networks are pervasive in various fields such as chemistry, biology, and sociology. In chemistry, first-order reaction networks are represented by a set of first-order differential equations, which can be constructed from the underlying energy landscape. However, as the number of nodes increases, it becomes more challenging to understand complex kinetics across different timescales.

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Spectral image (SI) measurement techniques, such as X-ray absorption fine structure (XAFS) imaging and scanning transmission electron microscopy (STEM) with energy-dispersive X-ray spectroscopy (EDS) or electron energy loss spectroscopy (EELS), are useful for identifying chemical structures in composite materials. Machine-learning techniques have been developed for automatic analysis of SI data and their usefulness has been proven. Recently, an extended measurement technique combining SI with a computed tomography (CT) technique (CT-SI), such as CT-XAFS and STEM-EDS/EELS tomography, was developed to identify the three-dimensional (3D) structures of chemical components.

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Exact solution to quantum dynamical activity.

Phys Rev E

April 2024

Department of Information and Communication Engineering, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8656, Japan.

The quantum dynamical activity constitutes a thermodynamic cost in trade-off relations such as the quantum speed limit and the quantum thermodynamic uncertainty relation. However, calculating the quantum dynamical activity has been a challenge. In this paper, we present the exact solution for the quantum dynamical activity by deploying the continuous matrix product state method.

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Information geometric bound on general chemical reaction networks.

Phys Rev E

April 2024

Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido 060-0814, Japan.

We investigate the convergence of chemical reaction networks (CRNs), aiming to establish an upper bound on their reaction rates. The nonlinear characteristics and discrete composition of CRNs pose significant challenges in this endeavor. To circumvent these complexities, we adopt an information geometric perspective, utilizing the natural gradient to formulate a nonlinear system.

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Binding Mechanism between Platelet Glycoprotein and Cyclic Peptide Elucidated by McMD-Based Dynamic Docking.

J Chem Inf Model

May 2024

Graduate School of Information Science, University of Hyogo, 7-1-28 minatojima Minami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.

The cyclic peptide OS1 (amino acid sequence: CTERMALHNLC), which has a disulfide bond between both termini cysteine residues, inhibits complex formation between the platelet glycoprotein Ibα (GPIbα) and the von Willebrand factor (vWF) by forming a complex with GPIbα. To study the binding mechanism between GPIbα and OS1 and, therefore, the inhibition mechanism of the protein-protein GPIbα-vWF complex, we have applied our multicanonical molecular dynamics (McMD)-based dynamic docking protocol starting from the unbound state of the peptide. Our simulations have reproduced the experimental complex structure, although the top-ranking structure was an intermediary one, where the peptide was bound in the same location as in the experimental structure; however, the β-switch of GPIbα attained a different conformation.

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Highly-integrable analogue reservoir circuits based on a simple cycle architecture.

Sci Rep

May 2024

Faculty of Information Science and Technology, Hokkaido University, Kita 14, Nishi 9, Kita-ku, Sapporo, Hokkaido, 0600814, Japan.

Article Synopsis
  • Physical reservoir computing offers a way to speed up AI computations by using physical systems that have nonlinear and fading-memory characteristics.
  • There is a high demand for physical reservoirs that are easy to integrate for edge AI computing, but creating high-performing and highly integrable reservoirs remains tough.
  • This study introduces an analogue circuit reservoir with a simple architecture designed for CMOS chip integration, demonstrating strong prediction performance and memory capacity in tests with both synthetic and real-world data, indicating potential for advanced AI accelerators.
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Electrodes are crucial for controlling the movements of biohybrid robots, but their external placement outside muscle tissue often leads to inefficient and non-selective stimulation of nearby biohybrid actuators. To address this, we propose embedding pillar electrodes within the skeletal muscle tissue, resulting in enhanced contraction of the target muscle without affecting the neighbor tissue with a 4 mm distance. We use finite element method simulations to establish a selectivity model, correlating the VI(volume integration of electric field intensity within muscle tissue) with actual contractile distances under different amplitudes of electrical pulses.

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Odd Response-Induced Phase Separation of Active Spinners.

Research (Wash D C)

May 2024

Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.

Due to the breaking of time-reversal and parity symmetries and the presence of non-conservative microscopic interactions, active spinner fluids and solids respectively exhibit nondissipative odd viscosity and nonstorage odd elasticity, engendering phenomena unattainable in traditional passive or active systems. Here, we study the effects of odd viscosity and elasticity on phase behaviors of active spinner systems. We find the spinner fluid under a simple shear experiences an anisotropic gas-liquid phase separation driven by the odd-viscosity stress.

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Music has profoundly shaped the human experience across cultures and generations, yet its impact on our minds and bodies remains elusive. This study examined how the perception of musical chord elicits bodily sensations and emotions through the brain's predictive processing. By deploying body-mapping tests and emotional evaluations on 527 participants exposed to chord progressions, we unveiled the intricate interplay between musical uncertainty, prediction error in eliciting specific bodily sensations and emotions.

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A method to analyze gene expression profiles from hippocampal neurons electrophysiologically recorded .

Front Neurosci

April 2024

Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan.

Hippocampal pyramidal neurons exhibit diverse spike patterns and gene expression profiles. However, their relationships with single neurons are not fully understood. In this study, we designed an electrophysiology-based experimental procedure to identify gene expression profiles using RNA sequencing of single hippocampal pyramidal neurons whose spike patterns were recorded in living mice.

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Article Synopsis
  • The study investigates the use of a heart rate variability (HRV) index derived from machine learning as a biomarker for drug-induced convulsions, focusing on its effectiveness with various convulsants.
  • Different doses of convulsants and non-convulsants were administered to telemetry-implanted male subjects, and the convulsive potential was analyzed using HRV data and statistical methods.
  • Findings suggested that the convulsive index increased for certain convulsants at lower doses, while the methodology has potential for predicting autonomic nervous activity fluctuations, although it may produce false positives.
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The absence of some forms of non-verbal communication in virtual reality (VR) can make VR-based group discussions difficult even when a leader is assigned to each group to facilitate discussions. In this paper, we discuss if the sensor data from off-the-shelf VR devices can be used to detect opportunities for facilitating engaging discussions and support leaders in VR-based group discussions. To this end, we focus on the detection of suppressed speaking intention in VR-based group discussions by using personalized and general models.

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Periportal macrophages protect against commensal-driven liver inflammation.

Nature

May 2024

Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan.

Article Synopsis
  • The liver helps control what comes from the gut, with different zones having unique immune functions.
  • Special immune cells called macrophages in one zone (PV) can reduce inflammation and depend on friendly gut bacteria to work properly.
  • If these macrophages don't function well, it can lead to liver diseases and more inflammation, showing how important they are for keeping the liver healthy.
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Chaotic neural dynamics facilitate probabilistic computations through sampling.

Proc Natl Acad Sci U S A

April 2024

Laboratory for Neural Computation and Adaptation, RIKEN Center for Brain Science, Saitama 351-0198, Japan.

Cortical neurons exhibit highly variable responses over trials and time. Theoretical works posit that this variability arises potentially from chaotic network dynamics of recurrently connected neurons. Here, we demonstrate that chaotic neural dynamics, formed through synaptic learning, allow networks to perform sensory cue integration in a sampling-based implementation.

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Coupling and uncoupling growth and product formation for producing chemicals.

Curr Opin Biotechnol

June 2024

Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka 565-0871, Japan. Electronic address:

Article Synopsis
  • Microbial fermentation can be done using two main strategies: one where growth is linked to production (growth-coupled) and another where they are separate (nongrowth-coupled).
  • Utilizing stoichiometric metabolic models with flux balance analysis helps enhance the engineering processes for target synthesis, particularly in growth-coupled systems, which can also aid in overcoming production bottlenecks through evolution.
  • For cost-effective production of bulk chemicals, adopting a nongrowth-coupled approach is essential; this requires careful management of the transition from growth to production modes and ensuring cellular activity remains high even when not growing.
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Embedding Bifurcations into Pneumatic Artificial Muscle.

Adv Sci (Weinh)

July 2024

Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8654, Japan.

Harnessing complex body dynamics has long been a challenge in robotics, particularly when dealing with soft dynamics, which exhibit high complexity in interacting with the environment. Recent studies indicate that these dynamics can be used as a computational resource, exemplified by the McKibben pneumatic artificial muscle, a common soft actuator. This study demonstrates that bifurcations, including periodic and chaotic dynamics, can be embedded into the pneumatic artificial muscle, with the entire bifurcation structure using the framework of physical reservoir computing.

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Genomic Evidence for the Complex Evolutionary History of Macaques (Genus Macaca).

J Mol Evol

June 2024

Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, People's Republic of China.

The genus Macaca is widely distributed, occupies a variety of habitats, shows diverse phenotypic characteristics, and is one of the best-studied genera of nonhuman primates. Here, we reported five re-sequencing Macaca genomes, including one M. cyclopis, one M.

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In this study, we investigate the effectiveness of noise reduction in electron holography, based on the wavelet hidden Markov model (WHMM), which allows the reasonable separation of weak signals from noise. Electron holography observations from a NdFeB thin foil showed that the noise reduction method suppressed artificial phase discontinuities generated by phase retrieval. From the peak signal-to-noise ratio, it was seen that the impact of denoising was significant for observations with a narrow spacing of interference fringes, which is a key parameter for the spatial resolution of electron holography.

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Infrared neural stimulation (INS) is a promising area of interest for the clinical application of a neuromodulation method. This is in part because of its low invasiveness, whereby INS modulates the activity of the neural tissue mainly through temperature changes. Additionally, INS may provide localized brain stimulation with less tissue damage.

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Necl-1/CADM3 regulates cone synapse formation in the mouse retina.

iScience

April 2024

Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan.

Article Synopsis
  • The study investigates retinal neural circuitry in vertebrates, focusing on the outer plexiform layer where photoreceptors connect with bipolar and horizontal cells for visual perception.
  • It identifies Necl-1/CADM3 as a crucial factor for synapse formation between S- and S/M-opsin cones and type 4 OFF cone bipolar cells (CBCs) in the mouse retina.
  • Mice lacking Necl-1 displayed abnormal synapse positioning and impaired visual responses, indicating that Necl-1 plays a key role in facilitating OFF pathways for short-wavelength light processing.
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Plasma proteomics profile-based comparison of torso versus brain injury: A prospective cohort study.

J Trauma Acute Care Surg

October 2024

From the Department of Traumatology and Acute Critical Medicine (J.T., Y.T., H.M., T.M., H.O., J.O.), Osaka University Graduate School of Medicine; and Department of Bioinformatic Engineering (S.S.), Graduate School of Information Science and Technology, Osaka University, Osaka, Japan.

Background: Trauma-related deaths and posttraumatic sequelae are a global health concern, necessitating a deeper understanding of the pathophysiology to advance trauma therapy. Proteomics offers insights into identifying and analyzing plasma proteins associated with trauma and inflammatory conditions; however, current proteomic methods have limitations in accurately measuring low-abundance plasma proteins. This study compared plasma proteomics profiles of patients from different acute trauma subgroups to identify new therapeutic targets and devise better strategies for personalized medicine.

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Enhancement of neural crest formation by mechanical force in development.

Int J Dev Biol

April 2024

Department of Life Sciences (Biology), Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.

In vertebrate development, ectoderm is specified into neural plate (NP), neural plate border (NPB), and epidermis. Although such patterning is thought to be achieved by molecular concentration gradients, it has been revealed, mainly by analysis, that mechanical force can regulate cell specification. During patterning, cells deform and migrate, and this applies force to surrounding tissues, shaping the embryo.

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Spintronic virtual neural network by a voltage controlled ferromagnet for associative memory.

Sci Rep

April 2024

Graduate School of Information Science and Technology, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8656, Japan.

Article Synopsis
  • Researchers explored a virtual oscillator network using a single spintronic oscillator to address issues like inconsistencies in conventional neural networks based on real oscillators.
  • The proposed solution involves using a ferromagnet controlled by voltage-controlled magnetic anisotropy (VCMA) to minimize energy dissipation, reducing Joule heating from electric currents.
  • The study successfully demonstrated associative memory operations for recognizing alphabet patterns by linking colors in patterns to the sign of a magnetic anisotropy coefficient, which can be manipulated through the VCMA effect.
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