授業の内容や構成
Course Content / Plan | | Themes of Graduation Research-Experiments in 2021
Particle Physics
* F laboratory (Fundamental Particle Physics Laboratory)
Since 1980's, we have been carrying out researches for elementary particles physics with nuclear emulsion,which can individually record tracks of elementary particles in sub-micron accuracy. In 2000, for example, we succeeded to find tau neutrino for the first time in the world and established the existence of muon neutrino to tau neutrino oscillation in 2015.
The following are the themes of our current studies. We are also making efforts to develop and improve detectors related to particle physics and astrophysics to promote these themes.
F-1 Study of neutrino physics
The existence of neutrino mass was confirmed by the observation of neutrino oscillation. However, many characteristics are still unknown such as absolute value and hierarchy of mass. Does right-handed neutrino exist? Is the neutrino Majorana particle? Is the CP-violating phase in the lepton sector non-zero? Tackle these challenging issues.
F-2 Directional dark matter detection
NEWSdm is the experiment for dark matter (WIMPS) search with ultra-fine grain nuclear emulsion, which is possible to detect the very short trajectory of the recoil atom caused by collision of with nucleus and dark matter. The goal is to demonstrate its existence and incoming direction of dark matter. This experiment is being started at Gran Sasso Laboratory in Italy. We also promote experimental research to explore the possibilities of dark matter candidates other than WIMPS.
F-3 Balloon borne gamma-ray telescope
Unknown gamma-ray sources exist in Universe such as galactic center gamma-ray excess. To investigate these objects, we promote the GRAINE project, which is balloon-borne gamma-ray telescope with the world's largest diameter ultra-high resolution nuclear emulsion telescope.
We are currently analyzing the Australian flight data in May 2018 and are aiming to demonstrate imaging at the world's highest resolution of gamma-rays imaging. The next flight will be scheduled in 2021 and we are developing the largest telescope, which have the capability of scientific observation as well.
F-4 Application research of nuclear emulsion
Non-destructive inspection for large structures such as volcanoes and pyramids using cosmic rays is a remarkable application research, which technics are derived from experiments of particle physics.
The nature field can also be thought of as an experimental field of unknown substances created in the early universe that human beings can never produce. The analysis of large-area nuclear emulsion plates irradiated on cosmic rays for non-destructive inspection brings possibility to explore these.
F-5 Development of particle detectors based on technologies including nuclear emulsion’s
We will progress with development of detectors based on nuclear emulsion technology.
Example 1) Detection of unknown short-range force: detection and measurement of wavefunctions of neutrons using ultra-fine grained nuclear emulsion.
Example 2) Development of automatic readout system for nuclear emulsion (speeding up, improvement of image detection)
Example 3) Production of nuclear emulsion from chemical substances and its development.
* N laboratory (High Energy Physics Laboratory)
N-1, N-2, N-3 Experimental Particle Physics
The goal of particle physics is to understand the fundamental principle of elementary particles and their interactions. According to the Standard Model (SM), six quarks and six leptons are the fundamental constituents of the matter, and their interactions are mediated by the gauge bosons such as the photon and the W bosons. The SM also explains masses of these particles by the Higgs mechanism. The N laboratory highly contributed to experimental verification of the SM; we confirmed the Kobayashi-Maskawa theory to explain the asymmetry between particles and anti-particles, and more recently we discovered the Higgs boson at the LHC experiment. Now, researches at the N laboratory focus on finding New Physics beyond the SM. For this purpose, we perform experiments at “LHC-ATLAS” and “Super B-Factory”. Our research would also lead to answering some of fundamental questions in the Universe like “What is the Dark Matter?” and “How are the present matter dominated Universe produced?”. The courses prepared for the fourth-grade students are shown in the following.
N-1 Super B-Factory Experiment
The B-factory experiment is based on the KEKB collider located at the High Energy Accelerator Organization in Japan. The N laboratory played a leading role in observation of CP violation in B meson decays, and verification of the Kobayashi-Maskawa mechanism leading to the Nobel prize in 2008. Now, we try to search for New Physics via precision measurements of the B-meson and tau-lepton decays at the Super-KEKB accelerator, which has 30 times more luminosity than the KEKB. Research topics for students include analyses of data obtained by KEKB/Super-KEKB, and its simulation study. These researches can be made by utilizing the super-computer owned by the N-laboratory.
N-2 LHC-ATLAS Experiment
The Large Hadron Collider (“LHC”) experiment is based on a proton-proton collider, which provides the world-highest center-of-mass energy of up to 14 TeV. A main subject of this experiment is the studies of the Higgs bosons for understanding the origin of masses of elementary particles. Another main subject is the search of new particles predicted by super-symmetric models and models including extra dimensions. The N laboratory has played a leading role in development and operation of the ATLAS muon detectors, which is essential in measuring new particles including the Higgs boson. In physics analyses, we have performed measurements of the top quark cross sections and Higgs properties. We also search for a new particle predicted by the models with extra dimensions. A student is expected to learn the basics of the LHC-ATLAS project through the development and operation of the muon detectors and also physics analysis of the data.
N-3 Development of Particle Detectors
Frontiers of particle physics have been explored by frontier accelerators and detectors. In N laboratory, we have developed a new particle detector called “TOP counter” for the Super B-Factory experiment. The TOP counter identifies the particle species very clearly by precise time measurement (50 pico-second!) of each Cherenkov photons generated in the quartz radiator. For LHC-ATLAS, we are developing a new trigger system to distinguish New Physics signal candidates from large backgrounds. A student can contribute to development of such new technologies, which will play essential roles for future discoveries !
* Φ laboratory (Laboratory of Particle Properties)
Experimental approaches to elementary particle physics can be categorized into two criteria: (1) direct observation of high energy particle reactions using high-energy accelerators (2) indirect observation of high energy phenomena in precision measurement of the contribution of higher-order quantum-loops of high-energy phenomena in low-energy processes. In the Phi-lab., slow neutrons from the most luminous pulsed neutron source at J-PARC (Japan Proton Accelerator Research Complex) will be mainly used to probe the properties of elementary particles. We also use muon and ion beam. The following is out list of on-going research items. We encourage students to consider to invent new approaches and welcome motivated students.
Φ-1 Neutron Decay Rate (Lifetime)
Neutron decay rate is a key parameter to define the weak interaction for quarks and also the primordial nucleosynthesis. Its experimental accuracy is still insufficient for precise verification of theoretical models. We are going to improve our understanding by improving accuracy and to search for non-standard interactions.
Φ-2 Study of the breaking of the symmetry under spatial-inversion and time-reversal in neutron-induced compound resonances
Large violation of the symmetry between matter and antimatter is required in order to explain our universe. We are now studying the enhancement of the symmetry breaking in neutron-nuclei reactions. The sensitivity of the search for the symmetry breaking in some reactions is competitive with that of neutron EDM. We are also developing some techniques for neutron spin control, polarization of target nuclei, and high-speed neutron detection to improve the sensitivity beyond standard model of particle physics.
Φ-3 Exotic Medium-range Forces (including extra-dimensions)
Gravitational interaction has been known to us before the physics was established, but least known in elementary particle physics due to its extraordinary weakness. However, the motion of slow neutrons apparently affected by geo-gravity since the neutral first order electromagnetism is missing for neutrons, that is electrically neutral. The advantage will be applied in the search for exotic medium-range forces including the search for possible effects of extra-dimensions.
Φ-4 Breaking of Time Reversal Symmetry (Neutron Electric Dipole Moment)
Neutron does not have the electric dipole moment (EDM) as long as the time-reversal symmetry is a valid symmetry. In reality, any non-zero value of neutron EDM has been measured so far. However, the asymmetry between matter and antimatter in the universe implies a finite value of EDM. The determination of neutron EDM is one of the most important observables to find a clue to the origin of the asymmetry. Extremely slow neutrons, that are sufficiently slow to be confined in bottles, are commonly applied for improving experimental sensitivity to the neutron EDM. We will study to apply precision neutron optics for measurements of neutron EDM. We are also trying to search the neutron EDM by measuring the effects of neutron wave through the non-centrosymmetric crystal.
Φ-5 Spin Correlation in Nuclear Beta Decay
Spin polarization of electrons emitted in the beta decay of polarized nuclei contains the information on the breaking of the time-reversal symmetry. The time-reversal symmetry is being tested in the measurement of electron polarization at the highest precision by observing the Mott scattering of electrons from polarized 8Li nuclei at TRIUMF laboratory in Canada.
In addition to above research items, we study “search for the violation of baryon number conservation law (also B-L violation) in neutron anti-neutron oscillation”, “search for chameleon field (a candidate of dark energy) with neutron interferometer”, and “precise measurement of the muonium hyperfine structure”.
Astrophysics
* A laboratory (Radio Astronomy Laboratory)
Understanding how stars and galaxies formed and have been evolved across the Hubble time is one of the biggest challenges in modern astrophysics. We are trying to address those big questions by millimeter / submillimeter observations of interstellar gas and dust in the Milky Way and external galaxies far away.
A-1 Submillimeter observations of distant galaxies
Distant star-forming galaxies which are rich in gas and dust give off a vast amount of energy in the far-infrared, which is cosmologically-redshifted and can be observed in the submillimeter wave in the present-day Universe. The student will exploit a series of multi-wavelength data, especially those taken with the ALMA and ASTE submillimeter telescopes, to investigate how star-formation and supermassive black hole growth are going in distant galaxies.
A-2 Instrumentation for the next-generation radio telescopes
Our research also includes development of technologies for the next-generation millimeter/submillimeter telescopes; (1) millimetric adaptive optics for instantaneously correcting radio wavefront disturbed by atmosphere and deformation of telescope optics, (2) ultra-wideband spectrograph based on superconducting resonators. The student will join one of the projects and learn instrumentation basics.
A-3 Observations of the molecular clouds in the Galaxy and nearby galaxies using the NANTEN2 telescope and analysis of the data.
In order to understand the distribution and nature of the molecular clouds in the Galaxy and nearby galaxies, you will join in the observations remotely from our lab. Through the observations, you will learn the system of the observations. You will also learn how to analyze the data and observations of the Galactic Center, low/high mass star forming regions, supernova remnants, high energy phenomena around black holes etc.
A-4 Developments of the multi-beam heterodyne receiver system and software
In order to increase the observational efficiency, we are developing multi-beam receiver system and related software including control of the instruments, telescope and data analysis. You will join developments of more than one topic and work with senior people.
* CR laboratory (Institute for Space-Earth Environmental Research; ISEE)
Cosmic rays are high-energy elementary particles, such as protons, gamma-rays, neutrinos and so on, coming to the earth from the space. Cosmic-ray protons also can probe interstellar magnetic fields and solar activity. We carry out experimental cosmic ray physics where two cutting-edge fundamental research fields, particle physics and astrophysics, cross over. Students with wide-scope of interests those who are fascinated by both of particle physics and astrophysics are encouraged to be enrolled in our CR-lab.
In graduated course of CR-lab, we conduct various projects of experimental cosmic ray physics such as gamma ray astronomy by Fermi and CTA, neutrino physics in Super-Kamiokande and WIMP dark matter search by liquid xenon in XENONnT, LHCf ; study of high energy cosmic ray interactions at LHC, study past solar energetic events by measuring cosmogenic nuclides such as radio carbon-14 in ancient tree rings, and so on. Related to these activities, 4th degree of students in our under-graduated course participate one of following independent topics to learn basic knowledge and techniques for experimental particle physics. In addition to these experimental efforts, we perform a seminar to read following text books in “journal club” style; “Cosmic Rays” by Minoru Oda, Shoka-bou (in Japanese), “Astroparticle Physics” by D.Perkins, (Oxford Univ. Press). We are also making an effort to promote data science education to give lectures on data analysis or to develop machine learning based data analysis.
CR-1 Direct dark matter searches by using liquid xenon detector at XENON and DARWIN
Dark matter, accounting for most of gravitational potential of the universe, is considered as WIMP, a yet undiscovered elementary particle. A liquid xenon TPC detector is the most promising technique to discover dark matter WIMP. Students will participate in activities of newly started XENONnt dark matter experiment and various detector development for a future 40-ton liquid xenon detector DARWIN by developing a homemade liquid xenon detector to learn/study cryogenic system or new ultra-violet photo-sensors, and basic of direct dark matter experiments.
CR-2 Cosmic-ray astrophysics with gamma-rays and neutrons.
Origins of cosmic rays can be studied with a neutral messenger particle such as gamma rays or neutrons since those particles are not bent by cosmic magnetic field. Students participate in development of a new Silicon photosensors to be used for the Cherenkov Telescope Array project or future gamma-ray satellites, and also participate in searches for dark matter or studies of acceleration mechanism of cosmic rays in cosmic-ray accelerator candidates such as supernova remnants or supermassive blackholes.
CR-3 Neutrino physics/astronomy using a large water Cherenkov detector.
Neutrino is a neutral particle with tiny mass and left-handed-only, which may connect to mysterious history of the early universe and baryogenesis. Students will participate to data analysis of Super-Kamiokande, a gigantic water Cherenkov detector, to study neutrino physics and neutrino astronomy. Students also may work on a new photo-sensors or develop analysis tools based on machine learning for future Hyper-Kamiokande currently being built.
CR-4 Hadronic interactions of ultra high energy cosmic rays.
The very high energy interactions by highest energy cosmic rays having 10**20 eV can be studied at LHC or at RHIC with a very forward angle detector LHCf/RHICf. Students can join the data analysis of such a very high energy intractions taken by LHCf/RHICf experimetns or develop a detectors used for future measurements, and also participate to Monte Carlo simulation study of high-energy cosmic ray air-showers in the atmosphere.
CR-5 Past cosmic rays activity probed by cosmogenic radiocarbon-14 and belilium-10.
Cosmogenic nuclide; radioisotopes produced by cosmic rays in the atmosphere, is an unique tool to understand past activity of cosmic rays and solar cycles at even >1000 years ago. Radiocarbon-14 in tree rings or belilium-10 in the ice-core of Antarctica can be used to search for past extreme solar events or nearby supernova or past solar cycles.variation of cosmic ray intensity a few 1000 years ago. Students participate data analysis of radiocarbon-14 to study ancient cosmic ray burst events, or variability of past solar activity.
* U laboratory (Space Astronomy Laboratory)
U-1, 2, 3, 4, 5 Infrared Astrophysics （Uir）
The main purpose of our research is to understand the properties of dust grains and gas under various environments in galaxies through near- to far-infrared observations using space-borne and ground-based telescopes. We have developed a far-infrared imaging spectrometer for AKARI, a Japan-led infrared astronomical satellite. (U-1) We are analyzing AKARI data extensively to pursue the above scientific researches. We are responsible for producing AKARI all-sky diffuse maps in the mid-infrared, the data of which are planned to be released to the public. (U-2) We are developing cryogenic optics and mid-/far-infrared detectors for future infrared astronomy satellite projects. (U-3) We are developing an optical to near-infrared spectrometer as a new focal-plane instrument for the IRSF 1.4 m telescope in South Africa. We are also developing a far-infrared spectrometer to be carried aboard the balloon-borne 1 m telescope in India. (U-4) Characterizing the atmospheres of habitable planets orbiting nearby stars is one of the most important scientific goals for observatories that will be developed in the 2020s and 2030s. Mid-infrared spectral features of H2O, CH4, O3, and other molecular species in the atmospheres of Earth-like planets are expected to have amplitudes of only ~ 10 parts-per-million (ppm) in transmission or emission spectra when transiting mid-or-late M-dwarf stars. We are developing a mid-infrared cryogenic testbed to assess the likely measurement precision of a future space telescope that would make these observations, collaborating with NASA Ames Research Center. In this study, a sub-system that will be attached to the cryogenic testbed at NASA Ames is developed. (U-5) Infrared astronomy plays an important role in understanding the formation of population III in the era of cosmic reionization and searching for life in the universe. However, the angular resolutions of current and planned space-based infrared telescopes are largely worse than in the other wavelength ranges (optical, near-infrared, and radio). Constructing an infrared interferometer in space by using multiple satellites could break the limitation. We are leading the development of space infrared interferometers in the world. In this study, we will focus on the far-infrared detector and optics for the balloon-borne far-infrared interferometer that will be launched in the mid 2020s.
U-6 Development of the quantum locking technique to beat the standard quantum limit for the detection of the primordial gravitational waves (Uxg)
Space gravitational-wave antenna, DECIGO is a future Japanese mission with objectives of detecting the primordial gravitational waves coming from the Universe’s inflation era to reveal the secret of the birth of the Universe. However, since the expected amplitude of the primordial gravitational waves is uncertain, it is necessary to increase the achievable sensitivity of DECIGO as much as possible. Therefore, we invented “the quantum locking technique with optical spring.” With this technique, it is possible to beat the standard quantum limit due to the uncertainty principle. In this research, we will do a theoretical analysis and an experiment to validate this technology's principle, establish the best conceptual design, and evaluate the achievable sensitivity.
U-7 Development of the displacement-noise-free neutron interferometer for the detection of the primordial gravitational waves (Uxg)
The best frequency band for the detection of the primordial gravitational waves is 0.1 to 1 Hz. However, the standard ground-based laser interferometric gravitational wave detectors have low sensitivity in this frequency band because of mirror’s displacement noise, such as seismic noise. Therefore, we invented “the displacement-noise-free neutron interferometer” by combining the mirror-displacement cancellation method, which we previously invented, and the neutron interferometer. With this technique, it may be possible to detect the primordial gravitational waves on earth. In this research, we will do a theoretical analysis and an experiment to validate this technology’s principle, establish the best conceptual design, and evaluate the achievable sensitivity.
Condensed Matter Physics
* I laboratory (Solid State Magnetic Resonance Laboratory)
The I laboratory (condensed-matter nuclear magnetic resonance laboratory) belongs to a group of experimental condensed matter physics. The current research interests are focused on unraveling anomalous magnetism and superconductivity of condensed matter, particularly, 3d transition metal oxides and Fe-based superconductors. First you learn magnetism, superconductivity, and nuclear magnetic resonance (NMR) via a laboratory seminar. Then you synthesize their samples and make x-ray, electric resisitivity, magnetic susceptibility, and NMR measurements. Based on the experimental data obtained, you discuss origin and mechanism of their magnetism and superconductivity.
* J laboratory (Laboratory of Nanomagnetism and Spintronics)
The group’s research focus is on nanoscale magnetism and spin related effects, aiming at discovering novel concepts in condensed matter physics. Research study in nanostructures allows us to address the challenging questions in the field of spin-related phenomena by artificially designing and fabricating nanostructures. A number of remarkable new physical effects associated with the conservation law of angular momentum and energy have been already discovered designing artificial interfaces, where strong electron-phonon-spin coupling emerges at nanoscale. Quite the opposite, revealing the physics underlying provides a fundamental basis and means for manipulating the physical phenomena. In this course, you will be trained in state of the art techniques such as growth of nanoscale materials, fabrication, and magnetic and transport measurements, and will enjoy the superb flavor of condensed matter physics. The group’s current research programs are divided into the following key themes.
J-1 Cross-correlations in multiferroic heterostructures
J-2 Quasi-particle transmission and tunnelling
J-3 Magnon-phonon coupling and thermal transport
J-4 Correlation of spin current and magnetic orders
J-5 Electron correlations at magnetic/superconducting interfaces
* V laboratory (Laboratory of Condensed-Matter Physics of Functional Materials)
We are interested in the sample syntheses and precise measurements for useful and interesting materials. Our research field covers a wide variety of functional properties in correlated electron systems; a large thermoelectric power in transition-metal oxides, nonlinear conduction phenomena in organic conductors, and magneto-dielectric behavior in novel low-dimensional materials. Basic understanding of electromagnetism, thermal/statistical physics, and quantum mechanics is prerequisite for graduate research. Typical subjects are listed below:
V-1 New physical phenomena from competing orders
V-2 Search for colossal responses in new semimetals
V-3 New functional materials with unique crystal structure
* Y laboratory (Materials Response Laboratory)
Our group focuses on various response properties of materials, including the dielectric response, the optical response, the magnetic response, the thermal response, and the mechanical response. Based on their fundamental mechanisms clarified from a viewpoint of the structure-property relationship, we address designing of functional materials, which lead innovation in science and technology. Current themes in our lab are listed below:
Y-1 Environmentally-friendly functional dielectric materials
Y-2 Novel ferroelectric materials
Y-3 Novel properties in quasicrystals
Y-4 Search for new quasicrystals and approximants
Biophysics
* D laboratory (Laboratory of Biomolecular Dynamics and Function)
Proteins are inherently dynamic molecules that undergo structural changes and interactions with other molecules over a wide timescale range, from nanoseconds to milliseconds or longer. Furthermore, protein motions play various important biological roles on assembly into protein complexes, ligand binding and enzymatic reactions. Therefore, understanding the dynamic behavior of a protein is a requisite for gaining insight into their function mechanisms. We develop novel methods for directly observing proteins’ dynamics based on high-speed atomic force microscopy (AFM), which is one of scanning probe microscopy, and exploit new paradigm of dynamic structural biology. Also we analyze structural dynamics of rhodopsin at atomic resolution using X-ray crystallographic technics for understanding the molecular mechanism and creating new functional GPCRs.
D-1 Direct observation of dynamic behavior of biological molecules and elucidating theirs function mechanism
Unique functions of proteins are often elicited by global conformational changes after local ones due to environmental change, ligand bind and molecular interactions. We observe the conformational dynamics of molecules such as motor and membrane proteins with high-speed AFM and elucidate molecular mechanisms of the protein’s functions.
D-2 Developments of novel microscopy techniques
In biological molecules, not only structures but also local electric and mechanical properties play crucial roles for physiological functions. We develop novel functions of HS-AFM enabling local mapping of various properties in addition to topography of biological molecules. Further we develop combined systems of HS-AFM with state-of-art single-molecule imaging techniques such as single-molecule fluorescence microscopy towards analysis of more complex biological systems.
D-3 X-ray structural biology of rhodopsin
We perform structural analysis on conformational dynamics of rhodopsin during the photocycle using advanced synchrotron radiation and newly developed X-ray free-electron laser to understand the molecular mechanism of activation rhodopsin. We also challenge to create novel functional rhodopsins on the basis of these accurate structures.
* G laboratory (Photo-Bioenergetics Laboratory)
Proteins are extremely elaborate ‘nano-devices’ that have been formed during evolution for 4 billion years. Photosynthesis performed by plants and cyanobacteria realizes light-energy conversion with an extremely high quantum yield using a number of pigments and metal ions embedded in proteins. To understand this most basic and significant biological process, it is necessary to clarify the mechanisms of light-energy conversion in the photosynthetic ‘nano-devices’. In our laboratory, we investigate the molecular mechanisms of the reactions in photosynthetic proteins using various physical methods such as vibrational spectroscopy, electron spin resonance, and quantum chemical calculations. Students in the 4th grade challenge their own research themes mastering basic experimental and analytical techniques, like preparations of biological samples, spectroscopic measurements, and analyses using computer calculations.
G-1 Mechanism of light-energy conversion in photosynthetic proteins
In photosynthesis, successive processes of light absorption, excitation transfer, charge separation, electron transfer, and proton transfer take place upon light illumination in the time scale from femtoseconds to milliseconds. It is also possible to trap the intermediate states after charge separation at cryogenic temperatures. The molecular mechanism of light-energy conversion in photosynthesis is investigated by detecting reactions and intermediates in photosynthetic proteins using various spectroscopic methods.
G-2 Molecular mechanism of photosynthetic oxygen evolution
The mechanism of photosynthetic oxygen evolution remains to be the biggest mystery in photosynthesis researches. Although oxygen evolution is known to be performed by water oxidation at the Mn4CaO5 cluster in photosystem II protein complexes, the detailed reaction mechanism has not been well understood. We challenge the clarification of water oxidation mechanism utilizing spectroscopic methods such as infrared spectroscopy and electron spin resonance.
* Ｋ laboratory (Laboratory of Cellular Signaling Biophysics)
Our laboratory aims at understanding the mechanisms of the information conversion and communication occurring in biological systems at the molecular and cellular levels. We focus on the mechanisms of protein folding / complex formation as the research at the molecular level (K-1). We also focus on the mechanisms of communication between nerve cells at the synapse as the research at the cellular level (K-2). The specific aims and the details of the research are described below.
K-1 Protein folding mechanisms
Proteins are biological macromolecules consisting of a series of amino acids, and indispensable in almost all aspects of biological phenomena. Proteins play their roles in biological systems only after they form their own specific three-dimensional structures and often multimeric complex. The conversion from an ensemble of the unstructured conformations without biological functions to the specific native structures is referred to as protein folding. There are many questions to be addressed in their physicochemical mechanisms although the protein folding / assembly is important in that these phenomena are associated with biology as well as molecular science. For the purpose of addressing the questions, our laboratory studies the mechanisms of proteins folding / assembly by means of our own ultrarapid mixing devices and spectroscopy. The details of the course are molecular biology to construct variant proteins, expression and purification of proteins, spectroscopic measurements of proteins and kinetic measurements of protein folding / assembly.
K-2 Research on the mechanism of synaptic transmission
In the nervous system, communications between nerve cells are executed through chemical synapses. In the presynaptic process, inflow of Ca2+ through Ca2+ channels opened by an action potential triggers the exocytosis of neurotransmitter through the fusion of synaptic vesicles with presynaptic membrane. When nerve is repeatedly stimulated, the amount of transmitter released gradually increases. This phenomenon, synaptic plasticity, is essential for higher function of brain as memory and learning. You study about the presynaptic mechanism and its regulation, especially modulation of transmitter release and dynamics of divalent cations, with the preparation of frog neuromuscular junction synapses using electrophysiological methods and ion-imaging techniques. |
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