th
5 IFQMSThe 5th International Forumon Quantum Metrology and Sensing

PROCEEDINGS
Short Presentation Session for Young Scientists
Part 2: SE-03B

29 November, 2022
Online Conference (Zoom)
Joint Program Session with Quantum Innovation 2022

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)
Quantum Sensing Track : Short Presentations by Young Researchers
SE-03B. Short Presentations by Young Researchers on SE-01, 04, 06, 07 Topics [5th IFQMS]*Note: Depending on the program, the order of presentations may change within the same group
All the times in the program are Japan Standard time (GMT+9)
Nov 29 (Tue.)

13:10-14:30

14:50-16:10

Session / Presentation

Mentor Chair Co-chair /Presenter

Affiliation

Abstract ID

SE-03B-α1. Break-out Session 1
Chair

Noriaki Yahata

QST

Co-chair

Hidetoshi Kono

QST

Structural dynamics of the Mn4CaO5 cluster during the S2-S3 transition inphotosystem II

Hongiie Li

Okayama U

SE-03B-α1-01

Visualization of hydrogen in Photosystem II by high-resolution Cryo-EM
analysis

Fusamichi Akita

Okayama U

SE-03B-α1-02

Pulsed-EPR study for radical reactions with biological anitioxidants utilizing
quantum effect of electron spin

Hiroki Hirano

Kanagawa U

SE-03B-α1-03

Coherent control of radical pair by local optimization theory

Akihiro Tateno

Saitama U

SE-03B-α1-04

Probing the coherent spin dynamics of radical pairs in weak magnetic fieldusing nanoseconds field switching technique

Ryusei Nozawa

Saitama U

SE-03B-α1-05

Role of a tyrosine radical in the photoreaction of chicken Cryptochrome 4, aHiroaki Otsuka
magnetoreceptor candidate molecule

Waseda U

SE-03B-α1-06

Cavity ring-down measurements by continuous pulse trains for magnetic
field effects on transient radical species.

Tsubasa Kimura

Saitama U

SE-03B-α1-07

Germanium vacancy defects in detonation nanodiamonds for temperaturesensing

Fu Haining

Kyoto U

SE-03B-α1-08

Evaluation of the surface-modified nanodiamond probes by in vivo
fluorescence imaging

Koki Okamoto

Tokyo Tech

SE-03B-α1-09

Detection of heat generation from biological system using double quantum
Hitoshi Ishiwata
thermometry

QST

SE-03B-α1-10

The Anomalous Formation of Irradiation Induced Nitrogen-Vacancy Centers
Frederick Tze Kit SO
in 5-Nanometer-Sized Detonation Nanodiamonds

Kyoto U

SE-03B-α1-11

Microwave antenna architecture for quantitative prediction of ODMR
signals

Keisuke Oshimi

Okayama U

SE-03B-α1-12

Chair

Yoichi Takakusagi

QST

Co-chairRyoko Araki

QST

SE-03B-α2. Break-out Session 1

An Artificial Intelligence Nanopore Platform Detects Omicron SARS-CoV-2 inKaoru Murakami
clinical samples

Hokkaido U

SE-03B-α2-01

Non-equilibrium phi4 theory in a Hierarchy:
Towards Manipulating Holograms in Quantum Brain Dynamics

Kobe U

SE-03B-α2-02

Construction of dipeptide-based DNP-NMR molecular probe library focusing
Yuki Aketa
on kidney injury mouse model

U TokyoSE-03B-α2-03

Nuclear hyperpolarization of liquid water by using photoexcited triplet
electrons in organic nanocrystals

Naoto Matsumoto

Kyushu U

SE-03B-α2-04

Development of Polarizing Agent with Controlled Electronic Structure forHighly Efficient triplet-DNP

Keita Sakamoto

Kyushu U

SE-03B-α2-05

DNP-NMR molecular probe for the detection of Dipeptidyl peptidase-4
activity in vivo

Akihito Goto

U TokyoSE-03B-α2-06

Generation of polarized triplet electron spins at solid-liquid interfaces

Reiya Yabuki

Kyushu U

SE-03B-α2-07

Photoreaction study of a primate blue-light sensitive photoreceptor using
vibrational spectroscopy

Yosuke Mizuno

Nagoya Tech

SE-03B-α2-08

Novel photoisomerization reaction in near-infrared light absorbing
enzymerhodopsins

Masahiro Sugiura

Nagoya Tech

SE-03B-α2-09

Development of a real-time 4D quantum temperature imaging system tomeasure intercellular thermal diffusivity

Haruka Maeoka

Hiroshima U

SE-03B-α2-10

Bidirectional neural network and its application to image denoising, superresolution, and image completion

Kei Majima

QST

SE-03B-α2-11

Molecular insight into photoactivation mechanism of BLUF protein by
QM/MM free energy simulation

Masahiko Taguchi

QST

SE-03B-α2-12

Akihiro Nishiyama

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-01

Structural dynamics of the Mn4CaO5 cluster during the S2-S3 transition inphotosystem II
Hongjie Li1, Yoshiki Nakajima1, Daichi Yamada2, Kana Hashimoto1, Minoru Kubo2,3, So Iwata3,4,Michihiro Suga1 and Jian-Ren Shen1
1

Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology,
Okayama University, Okayama, Japan
2
Graduate School of Science, University of Hyogo, Hyogo, Japan,
3
RIKEN SPring-8 Center, Hyogo, Japan
4
Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan

Introduction
Photosystem II (PSII) catalyzes light-induced water oxidation through the Si-state cycle at its oxygen-evolving catalyst, a
Mn4CaO5 cluster. During this process, four electrons and four protons are released from two water molecules, and one dioxygen molecule is evolved. Pump-probe time-resolved serial femtosecond crystallography (TR-SFX) has been used tocapture several intermediate states of PSII, deepening our understanding of the water oxidation reaction. Significantly, a
newly inserted oxygen O6 was observed in the vicinity of O5 in the S3-state before the di-oxygen formation1,2. However, theorigin of the O6 and the mechanism to incorporate it remain to be elucidated. To address this issue, we analyzed the structuraldynamics of PSII during the onset of S2-S3 state transition at various time points from nanoseconds to milliseconds after two
flashes (2F) illumination using an X-ray free electron laser at SACLA, Japan.
Following the 2nd flash, no difference electron densities was observed within 20 ns. Instead, from 200 ns to 30 µs, paired
positive and negative difference densities appeared in the area around Q165 and YZ, which was decreased at 200 µs andvanished at 5 ms following the 2nd flash (Fig. 1). Refined models demonstrate that Q165 and YZ move in the same direction
during 200 ns to 30 µs and restore by 5 ms. These movements can be explained by the oxidation and re-reduction of YZ
during the S2-S3 state transition.
One positive density close to the Ca2+ ion, constructed with a water molecule and designated as O6*, appeared during 1µs to 200 µs and vanished at 5 ms, with the concomitant increase of the O6 density from 30 µs to 5 ms (Fig. 1). We speculatethat this water is the origin of O6 and is translocated via the Ca2+ ion binding site to the O6 site. Following the insertion of
O6, Mn4 and Mn1 move apart from each other, opening the Mn4CaO5 cluster and presumably preparing for subsequent dioxygen release in the next state transition.
These results provide important insights into the molecular mechanism of water oxidation in PSII.

Fig. 1. Structural dynamics around the Mn4CaO5 cluster during the S2-S3 transitions. Refined structures are superposedwith Fobs (2F) – Fobs (1F) difference density maps contoured at +3.5 (green) and -3.5 (orange) from 20 ns to 5 ms. The 1F
structure is in grey and the 2F intermediate structure is colored. Black dot lines depict hydrogen bonds. Black arrows
represent structural changes.

Reference
1

Suga, M. et al., Nature 543, 131-135 (2017)
Suga, M. et al., Science 366, 334-338 (2019)2

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-02
Visualization of hydrogen atoms in Photosystem II by high-resolution Cryo-EM analysis
Fusamichi Akita1, Radostin Danev2,3, Yoshiki Nakajima1, Huaxin Yu4, Koji Kato5, Naoyuki
Miyazaki6, and Jian-Ren Shen1
1

Research Institute for interdisciplinary Science, Okayama University
2
Graduate School of Medicine, The University of Tokyo
3
PRESTO, Japan Science and Technology Agency
4
Microbial Sciences Institute, Department of Microbial Pathogenesis, Yale University
5
Structural Biology Division, Japan Synchrotron Radiation Research Institute6
Osaka Research Center for Drug Discovery, Otsuka Pharmaceutical Co., Ltd.
fusamichi_a@okayama-u.ac.jp
Introduction

Photosystem II (PSII) is a membrane protein supercomplex and functions to catalyze light-induced watersplitting, leading to the generation of electrons, protons, and molecular oxygen. PSII consists of 20 protein
subunits and several cofactors, chlorophylls, carotenoids, and the oxygen-evolving center (OEC) responsible
for splitting water through five intermediate states, S0, S1, S2, S3, and S4. The structure of PSII at 1.9 Å
resolution was solved in 2011, which revealed that the OEC has a “distorted chair” shape with a Mn4CaO5composition1. The structure of PSII without radiation damage at the S1 state was determined at 1.95 Å
resolution using femtosecond X-ray free electron lasers (XFEL)2. Subsequently, the S3 state was analyzed using
a time-resolved serial XFEL3, and the structural transition from S2 to S3 was determined using fixed-target
XFEL4. These studies showed the insertion of an oxygen atom (O6) into the vicinity of O5 in the Mn 4CaO5cluster, giving rise to a mechanism of O-O bond formation between O5 and O6. However, there has been little
discussion on the protonation states of residues and water molecules as well as hydrogen release pathways,
which require high-resolution structural analysis. Recent innovations in cryo-electron microscopy (Cryo-EM)
technology have made it possible to achieve high resolutions that may show hydrogen atoms. Here, we
analyzed the structure of PSII at 1.45 Å resolution using Cryo-EM. The difference map obtained showed peaks
arising from hydrogen atoms around amino acid residues and water molecules. In this presentation, I will
discuss the structural analysis of PSII by high-resolution cryo-EM, the protonation states of OEC and thehydrogen atom network.
Fig. The Cryo-EM map of PSII at 1.45 Å resolution. The blue andgreen maps indicate the original Cryo-EM map and the calculateddifference map, respectively.
Reference
1.
Umena Y., Kawakami K., Shen J.-R., Kamiya N., Crystal structure ofoxygen-evolving photosystem II at a resolution of 1.9 Å.Nature, 473, 55-60(2011).
2.
Suga M. et al., Native structure of photosystem II at 1.95 Å resolution
viewed by femtosecond X-ray pulses. Nature, 517, 99-103 (2015).
3.
Suga M. et al., Light-induced structural changes and the site of O=O
bond formation in PSII caught by XFEL. Nature, 543, 131-135 (2017).
4.
Suga M.et al., An open-cubane oxyl/oxo mechanism for O=O bondformation in PSII revealed by XFEL.Science, 366, 334-338 (2019).

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-03

Pulsed-EPR study for radical reactions with biological antioxidants
utilizing quantum effect of electron spin
Hiroki Hirano1, Kaito Marumo1, Ikuo Nakanishi2, Akio Kawai1,
1Graduated School of Science, Kanagawa university

Institute for Quantum Life Science, Quantum Life and Medial Science Directorate, National
Institutes for Quantum Science and Technology

2r201503326@jindai.jp
Introduction
Radicals are important species that are highly reactive and play an important role in biological reactions. Usually, aging
and disease of living body are caused by radicals. To protect these problems, there are many biological antioxidants in vivo.
The biological antioxidants work to eliminate highly reactive radicals by reacting with them and transform themselves into
stable radical species. A large number of studies have been made to determine radical reaction rate constants of biologicalantioxidants to evaluate radical trapping abilities1. What seems to be lacking, however, is the observation in elementary
reaction process, particularly in reactions with carbon-centered radicals. For understanding of the radical reactions, itis necessary to discuss them in terms of the kinetics of the elementary reaction process observations.
We have been investigating radical addition reaction mechanisms and rate constants by utilizing time-resolved (TR-) EPR
and pulsed-EPR2. These methods can observe elementary reaction process owing to their high time resolutions of several 10~ 100 ns. The radical reaction rate constants are obtained by measuring the electron spin echo (ESE) decay utilizing pulsedEPR. The ESE signal is given by the spin wave packet of radicals that are in coherent state. Therefore, the radicals can beselectively observed. In this study, we aim to investigate radical reactions of biological antioxidants by identifying thereaction product radicals and determine radical rate constant of biological antioxidants utilizing these techniques.

Experimental method
TR-EPR measurement was performed to identify the intermediate radicals formed by radical reactions of antioxidants.
Radical reaction rate constants of antioxidants were determined by ESE decay measurements. The radicals were generated
by photolysis of radical sources such as aromatic ketone compounds. As for the antioxidants, α-tocopherol (α-TocH) and tritert-butylphenol (TTBP) were used.

Results and Discussion
Fig.1 shows the ESE decays of 2-hydroxypropyl (2Hy-Pr) radical under
different α-TocH concentrations. The ESE of the radicals was generated by aconventional Hahn echo pulse sequence with a π/2 pulse and a τ-delayed π pulse,which was initiated at t ns after the laser flash (laser flash – t – π/2 – τ – π – τ –ESE). The decay was obtained by monitoring the ESE signal intensity, S(τ), forseries of τ values. The top line is the ESE decay of the 2Hy-Pr radical without
antioxidants. The ESE decay rate, 1/TM*, was determined by the exponential
decay fitting procedure of the S(τ) profile on the basis of the equation,2𝜏𝜏𝑆𝑆(𝜏𝜏) = 𝑆𝑆0 exp � ∗ �
𝑇𝑇𝑀𝑀with S0 (initial ESE amplitude) and TM* as a fitting parameter. Then, the ESE
decay measurements were performed with different concentrations of α-TocH(Fig.1). It was found that the 1/TM* was faster depending on the α-TocHconcentration. This is due to the elimination of 2Hy-Pr by the reaction with αTocH. 1/TM* of these decays were also determined and the results were plottedagainst the concentration of α-TocH (Fig.2). The liner relationship was obtained
and therefore, the radical reaction rate constant, k, was determined by the liner
fitting following the equation,
1
1+ 𝑘𝑘 [𝛼𝛼-TocH]
∗ =
𝑇𝑇𝑀𝑀
𝑇𝑇𝑀𝑀
where 1/TM is the α-TocH -independent the ESE decay rate. The determined kvalue was (3.2 ± 0.2) ×106 M-1 s-1. At the conference, we will discuss thereactivity of α-TocH by comparing the rate constant of TTBP.

Reference
1
2

Packer, J. E., Slater, T. F., and Willson, R. L., Nature, 278, 737–738 (1979)
H. Hirano, H. Takahashi, A. Kawai, J. Phys. Chem. B, 126, 6074-6082. (2022)

Fig.1 Time profiles of ESE intensity, S (τ), of 2Hy-Pr
under various α-TocH concentrations.

Fig.2 Stern-Volmer type analysis of 1/TM* of 2Hy-Pr
radical versus [α-TocH].

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-04

Coherent control of radical species by local optimization theory
Akihiro Tateno1, Kenta Masuzawa1, Hiroki Nagashima1, Michihiko Sugawara2, and Kiminori
Maeda1
1

Graduate School of Science and Engineering, Saitama University
2
Keio Quantum Computing Center, Keio University
a.tateno.275@ms.saitama-u.ac.jp

Introduction
Design of laser waveforms optimized for reaction control has attracted theoretical and experimental attention1. However,
it is not easy to realize the designed laser field. In contrast, recent progress of arbitrary wave generator (AWG) enables us
to produce the designed radio wave field (RF). Recently, we have shown that it is possible to control the recombination
reaction of a radical pair (RP) in high field using radio wave magnetic resonance designed based on the local optimization
theory1,2. As an example of coherent control, here we show the spin multiplicity control of RP at low fields and the designof optimized AWG pulse that induce selective spin echoes.
Coherent control in local optimization targets a transient state |𝑓⟩𝐿 that is non-eigenstate of the Hamiltonian at a specifictime tf. In order to produce |𝑓⟩𝐿 at tf, it is necessary to calculate the moving target |𝜌𝑓 ⟩𝐿 that time-evolves to |𝑓⟩𝐿 . |𝜌𝑓 ⟩𝐿
can be calculated by the time reverse Liouville operator as shown by|𝜌𝑓 ⟩𝐿 = 𝑒𝑥𝑝 {𝑖𝐿̂ 0 (𝑡𝑓 − 𝑡)} |𝑓⟩𝐿
We have chosen the singlet state and the Sy+Sz states as |𝑓⟩𝐿 for the reaction control of RPs and the selective spin echomeasurement, respectively.
The calculation for the spin multiplicity control was done in a model RP system having one nuclear spin (HFC A=0.5mT). In low magnetic field, almost all spin states are mixing coherently. We calculated an RF field with the aim ofcontrolling a singlet born RP to singlet state after 1 μs. The FIG.1a shows time-evolutions of the singlet probability inpresence and absence of designed RF field. The RF irradiation change the singlet probability at 1 μs after the productionof RP from 39 % to 96 %.
As a model system for selective control of spin systems, we used a mixed system of TEMPO (solution) and BDPA (solid)
whose stick diagram of the resonance lines is shown in FIG. 1b. In this system, we designed the RF waveform so that theelectron spin of TEMPO radical transitions to the Sy state for three hyperfine lines at t =200 ns keeping the electron spinof BDPA in the Sz state. FIG 1c shows that the calculated RF provides the FT-EPR spectrum of selectively excited TEMPO
radicals (solid line) whereas the spectrum obtained by composite pulse of three colour RF pulses contains the signal ofundesired the other radical (broken line).

(1)

(2)

(3)

FIG. 1) Upper: Calculated RF, Lower: Time-evolution of singlet probability. 2) Model system 3)Calculated spin echo
after optimised pulse(solid line) and after multi-colour pulse(dotted line)

References
1

M. Sugawara, J. Chem. Phys.118(15). 6784-6800 (2003).
K. Masuzawa, M. Sato, M. Sugawara, and K. Maeda, J. Chem. Phys. 152, 014301 (2020)2

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-05

Probing the coherent spin dynamics of radical pairs in weak magnetic fieldusing nanoseconds field switching technique
Ryusei Nozawa1, Taisuke Matuo1, Hiroki Nagashima1, Kiminori Maeda1
1

Department of Chemistry, Graduate School of Science and Technology, Saitama University.
r.nozawa.939@ms.saitama-u.ac.jp

Introduction
Recent discussions of the mechanism of magnetic sensitivity in animals have focused attention on the spin dynamics ofradical pairs in the low-field region and the effects of the magnetic field. The existence of low-field effects in radical pairs
is easy to confirm, since the magnetic field effects in radical pairs are in the opposite direction of those in the usual hyperfine
coupling and relaxation mechanisms, but there are many theoretical models that are believed to be responsible for themagnetic field effects.[1] Matsuo et al. used nanosecond magnetic field switching techniques for the xanthone-DABCO
system in SDS micelle solutions to analyze the behavior of radical pairs at weak magnetic fields and found the decay timeof the transient absorption change was extremely short only when the external magnetic field was changed from the peakmagnetic field of the low-field effect to zero field.[2] This result suggests that the origin of the low-field effect in this system
is not pseudo-normal spin mixing, but coherent due to the breaking of the degenerate electron-nuclear spin state. We also
thought we could observe a time equivalent to coherent low-field effect generation by applying nanosecond magnetic fieldswitching techniques. Based on these, the nanosecond magnetic field switching technique was further applied in this study
to four more magnetic fields exhibiting low-field effects to zero field to probe the coherent low-field effect generation process.

Method・Result
MARY spectra in the low-field region obtained in SDS micellar solutions of xanthone and DABCO are shown in FIG
1[a]. Transient absorption changes associated with magnetic field switching from four low magnetic fields(1.5, 1.1, 0.7, 0.4mT) to zero magnetic field were monitored and their post-laser delay time dependence plotted. Experimental resultson the curve of 𝑡 ≈ ℎ/2𝑔𝜇𝐵 𝐵0 as shown FIG1[b]. Comparing this result with the time evolution of the Singlet-likemagnetic field effect by the one-nucleus spin model, it reflects the most prominent time of the coherent onset of the lowfield effect due to the breaking of the degeneracy of the electron-nucleus spin state by the Zeeman energy. This indicatesthat the present method captures the generation of the low-field effect due to the breaking of the degeneracy in time. However,some other systems do not exhibit such ideal behavior and don’t reflect the coherent rise time. This indicates the possibilityof the influence of decoherence of spin systems, mechanisms of low-field effects other than degenerate breaking, and so on.

FIG.1. [a]Experimental results of MARY spectra of the Xanthone-DABCO system and thescheme for changing the magnetic field. [b] Calculation results magnetic field effects of Singlet in
the one-nuclear spin, and the result of inverse field switching.
Reference[1] 1Maeda, K. et al., Nature, 452,387-390(2008).
[2] 1Matuo.T., Master thesis(2018).

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-06

Role of a tyrosine radical in the photoreaction ofchicken Cryptochrome 4, a magnetoreceptor candidate molecule
Hiroaki Otsuka1, Ryosuke Miyake1, Keiko Okano1, Yasushi Imamoto2, and Toshiyuki Okano1
1

Department of Electrical Engineering and Bioscience, School of Advanced Science and Engineering,
Waseda University
2
Department of Biophysics, Graduate School of Science, Kyoto University
o1.2t5.8tt21.tf@ruri.waseda.jp

Introduction
Some animals have the ability of magnetoreception [1]. Interestingly, themagnetoreception of birds and insects is driven by light. As a possible mechanism of
the light-dependent magnetoreception, “Radical pair mechanism (RPM)” has been
proposed, in which the magnetosensitive bifurcation of reaction of two entangled
radicals (radical pair) formed by photoexcitation is used [2]. The magnetic sensor in
RPM would have the light-sensitivity and the ability of radical formation, andcryptochromes (CRYs) are considered to be candidates for the magnetoreceptor. Our
previous study revealed the ability of photoreception via flavin adenine dinucleotide
chromophore (FAD) and radical formation of CRY4 in the chick retina [3–5]. The
spectroscopic analysis of the transient reaction of chicken CRY4 (cCRY4) identified
a formation of FAD anion radical (FAD●‒) upon light absorption, which was reacted
into bifurcated reaction of oxidation or protonation. Interestingly, a neutral tyrosine
radical (Tyr-O●) like spectrum was detected with the formation of FAD●‒ and it
decayed along with the protonation of FAD●‒ [6]. According to RPM,
magnetosensitive reaction of bifurcation to reduction and oxidation is expected to a
key step. Although the detail role and the site of Tyr-O● formation are unknown, TyrO● could play an important role in the bifurcation.
In this study, we aim to identify the site of Tyr-O● formation and elucidate the roleof Tyr-O● in the photoreaction of cCRY4 by comparing the photoreaction of cCRY4tyrosine mutant with that of wild-type cCRY4.

MethodTyr319 is an amino acid locating near the fourth tryptophan that constitutes aputative electron-transfer pathway called Trp-tetrad in cCRY4, and it was mutatedto phenylalanine (F). Wild-type and Y319F mutant of recombinant cCRY4 wereexpressed by yeast expression system and purified by GST-tag-based purification
system. Steady-state photoreactions and their efficiencies were analyzed using
double beam spectroscopy (UV-2450). Transient reactions of each sample were
measured by laboratory-built, time-resolved spectrophotometry system.

FIG. 1. Reaction model ofcCRY4 WT and cCRY4 Y319F(A) FAD●‒ binding cCRY4 isbifurcated into oxidation form andprotonation form. Tyr-O● decays as
FAD●‒ oxidizes. (B) Almost FAD●‒
oxidizes in cCRY4 Y319F, and Trp●
is formed instead of Tyr-O●.

Results and discussion
The chromophore FAD in the dark-state of cCRY4 is oxidized (FADOX). Blue light irradiation reduces the FADOX to
FAD●‒, a part of which is immediately (subsecond order) protonated to a neutral radical form (FADH●). Quantum yield of
FADOX → FADH● in cCRY4 WT was 16%, while that in cCRY4 Y319F decreased to 6.0%. As reported previously, cCRY4
WT showed FAD●‒ formation immediately after photoexcitation (< 0.5 ms), followed by bifurcation to fast (≈ 100 ms)
oxidation (FAD●‒ → FADOX) and slow (≈ 400 ms) protonation (FAD●‒ → FADH●), the former of which was accompanied
by decay of Tyr-O● (FIG. 1A). In contrast, most of the FAD●‒ was oxidized in cCRY4 Y319F, and noticeably, spectra
resembling tryptophan neutral radicals (Trp●) instead of Tyr-O● were observed (FIG. 1B).
The observation of Trp●-like spectra in cCRY4 Y319F is consistent with the idea that Tyr319 donates electron to FAD
via Trp tetrad. The suppression of the FAD●‒ protonation in cCRY4 Y319F suggests a possible role of Tyr-O● in the
protonation.
Reference
1R. Wiltschko and W. Wiltschko, Adv. Exp. Med. Biol. 739, 126 (2012); 2T. Ritz, S. Adem, and K. Schulten, Biophys. J. 78, 707 (2000);
3Y. Kubo, M. Akiyama, Y. Fukada, and T. Okano, J. Neurochem. 97, 1155 (2006); 4R. Watari, C. Yamaguchi, W. Zemba, Y. Kubo,

K. Okano, and T. Okano, J. Biol. Chem. 287, 42634 (2012); 5H. Mitsui, T. Maeda, C. Yamaguchi, Y. Tsuji, R. Watari, Y. Kubo, K.
Okano, and T. Okano, Biochemistry 54, 1908 (2015). 6H. Otsuka, H. Mitsui, K. Miura, K. Okano, Y. Imamto, and T. Okano,
Biochemistry 59, 3615 (2020).

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-07

Cavity ring-down measurements by continuous pulse trains
for magnetic field effects on transient radical species.
Tsubasa Kimura1 and Kiminori Maeda1
1

Department of Chemistry, Graduated school of Science and Engineering, Saitama University
t.kimura.485@ms.saitama-u.ac.jp

Introduction
The magnetic field effect (MFE) measurements of photo-generated radical pairs in photochemical reactions fundamentallyneed very high sensitivity and long acquisition with many light pulse irradiations. The degradation due to the multiple pumppulse irradiations is a difficult concern when we apply to precious biological samples. Previously, the sensitivity problem
was solved with pump-probe type cavity ringdown (CRDS) method [1], which boosts the effective optical path length using
optical cavity. If we compared the CRDS with the cavity enhanced absorption spectroscopy (CEAS) [2], the CRDS ontransient absorption (TA) measurements has advantageous aspects: 1) free from correction of the wavelength dependent
cavity enhancement, 2) free from the fluctuations of the probe beam, 3) clear estimation of the time resolution.
Here we developed a new CRDS technique named super-CRDS (SCRDS) [3], which is sequential CRDS measurements
using a pulse train of a super continuum source (SC source). SCRDS allows us to measure the absorptions at many delay
times with 200 ns interval (5 MHz). Therefore, we can get the transient absorption (TA) time trace by a single excitation
simultaneously. This fact dramatically reduces the number of excitation light irradiations, keeping the sensitivity as same as
pump-probe CRDS.

MethodThe TA at 500~600 nm and its magnetic field effect were measured by SCRDS technique. The mixed aqueous solution of
FMN 50 μM and HEWL 200 μM, 40 mL was flown from a syringe pump to a sample cell (200 μL volume and 1 mm opticallength). The CRDS signal is penetrated from the back side of the cavity mirror and monitored by a photomultiplier tube. The
CRD signals are fit by a single exponential function for every delay times. The transient absorbances A per single pass ofthe probe light can be calculated by the lifetime of the signal  and that at the negative delay time  The TA was measured
in the field range from 0 to 20 mT. Pulsed magnetic fields, whose duration is 1.8 ms, were synchronized with the excitation
pulse laser. The flat region of the magnetic field in time was used for the TA measurements. In the MFE measurement, theabsorption was measured while the magnetic field was varied by 2 mT, and the absorption from 10 to 90 μs was averaged toobtain the magnetic field effect at each magnetic field. This process was repeated 200 times at each magnetic field.
Results
The intensity of the excitation light was adjusted to be comparable to that of Ref [1]. FIG. 1 is a plot of TA time profiles,
and FIG. 2 is a plot of MFE measurement. SCRDS requires only one-tenth of the number of shots, (200 shots), to measure
the TA for a single magnetic field intensity, and the error can be suppressed to ±0.25 %.

FIG. 1. Time-resolved transient absorption signal
in the system of FMN 50 μM and HEWL 200 μM.
The signal obtained by 100 shots laser excitation isaveraged.

FIG. 2. Magnetic field effect using SCRDS
in the system of FMN 50 μM and HEWL 200 μM.
200 shots averaged per points.

Acknowledgements: This work was supported by MEXT Q-LEAP Grant Number JPMXS0120330644

References: [1] Maeda, K et al., J. Am. Chem. Soc., 133, 17807–17815 (2011).
[2] Neil, S. R. T et al. J. Phys. Chem. B, 118, 4177-4184(2014).
[3] Japan Patent 2022- 7803.

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-08

Germanium Vacancy Defects in Detonation Nanodiamonds
for Temperature Sensing

Haining Fu1, Masanori Fujiwara1, Izuru Ohki1, Ming Liu2, Akihiko Tsurui2, Taro Yoshikawa2,
Masahiro Nishikawa2, and Norikazu Mizuochi1
1Institute for Chemical Research, Kyoto University
2
Daicel Cooperation
fu.haining.82r@st.kyoto-u.ac.jp

Introduction
Group IV color centers such as silicon-vacancy center (SiV) and germanium-vacancy center (GeV) in nanodiamonds (NDs)
are promising candidates for all-optical nanoscale thermometry. Because these defects have sharp zero phonon lines (ZPLs)
and the ZPL peak wavelength changes depending on local temperature. For live-cell application, NDs should be smaller than
30 nm to avoid non-invasive methods. However, the minimum size of NDs concluding group IV color centers as temperature
sensors reported was 200 nm [1]. This motivated us to synthesize NDs by detonation method, which is suitable for the mass
production of NDs in smaller size. In 2020, we reported the first synthesis of SiV-containing detonation nanodiamonds (SiVDNDs) [2]. Then, we performed all-optical thermometry with SiV-DNDs in an average size of 20 nm. This is the smallest
size applied for thermometry using color-center-containing NDs [3].
Compared to SiV center, GeV center shows higher quantum efficiency, and its ZPL peak wavelength is 100 nm shorter
than SiV center, make it a good candidate for temperature sensing. GeV-containing detonation nanodiamonds (GeV-DNDs)
has been synthesized successfully according to the recent report [4]. And in our current study, we focus on the temperaturesensing of GeV-DNDs, evaluated their PL spectrum response according to temperature. GeV center combining SiV centeris suitable for multi-color imaging application and local temperature measurements of live-cell organelles.
Methods & Results
After the detonation of explosives with Ge dopant, our sample was processed by purification, dispersion, surface
modification, and ultracentrifugation. Supernatant and suspension were collected as different samples. In addition, thesediment was also collected and dispersed into pure water as another sample. Each sample was dropped on a coverslip,
natural drying in the air atmosphere. A thermoplate is set to control the sample temperature. Each sample were observed andtaken photoluminescence (PL) image by a homebuilt confocal microscope.
Both the supernatant and suspension samples showed weak GeV centers’ ZPL signals at around 602 nm, and a strong PL
background signal from DND itself has been observed. In the sediment sample, however, we found a strong ZPL signal fromsome bright spots in PL image (Fig. 1(a)). These bright spots may be GeV-DND aggregations or large GeV-DND particles.
At these spots, we confirmed that the ZPL peak wavelength (λ) linearly red-shifted with increasing temperature (T) (Fig.
1(b)). The slope Δλ/ΔT is an indicator of the temperature response and the average value is 0.009 nm/K, which agrees with
the GeV center ensemble in a bulk diamond (0.008 nm/K) [5]. The particle distribution is investigated by transmission
electron microscope image. The average particle size is 20 nm, much smaller than the reported GeV-NDs for thermometry
application (400 nm) [6]. Finally, we measured and calculated the temperature sensitivity (ηT), which defined as thetemperature deviation (σT) per unit integration time (1s). As an example, a temperature sensitivity as 1.9 K Hz-1/2 measured
at a bright spot shows in Fig. 1(c), means that a sub-Kelvin temperature change can be measured in 10 seconds.
This work is supported by MEXT Q-LEAP (No. JPMXS0120330644).

Figure 1 (a) PL image of the GeV-DND sediment sample. (b) and (c) Temperature dependence and temperature sensitivity
measurements at the bright spot depicted in a white circle in (a).

Reference[1] C. T. Nguyen, et al., Appl. Phys. Lett. 112, 203102 (2018). [2] Y. Makino, et al., Diam. Relat. Mater. 112, 108248 (2021).
[3] M. Fujiwara, et al., Carbon, 198, 57 (2022). [4] Y. Makino, et al., Diam. Relat. Mater. 130, 109493 (2022) [5] S. Blakley,
et al., ACS Photonics, 6,1690 (2019). [6] T. T. Tran, et al., Sci. Adv. 5 eaav9180 (2019)

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-09

Evaluation of the surface-modified nanodiamond probes
by in vivo fluorescence imaging
Koki Okamoto1, Masaya Muto1, Tetsuya Kadonosono1, Kiichi Kaminaga2, Ryuji Igarashi2, andShinae Kizaka-Kondoh1
1

School of Life Science and Technology, Tokyo Institute of Technology
Institute for Quantum Life Science, National Institutes for Quantum Science and Technology
okamoto.k.am@m.titech.ac.jp

2

Introduction
In recent years, fluorescent nanodiamond have attracted attention as a novel in vivo imaging probe1. Nitrogen-vacancy
centers in nanodiamond have electrons whose quantum state (such as spin resonance frequencies) change according tochanges in the surrounding environment. This variation of quantum state can be used to develop environmentally responsive
sensor probes2, 3. Tumors have a unique and complex microenvironment characterized by hypoxia4, which is closely
associated with treatment resistance and malignant progression, making it important therapeutic targets. Early detection oftumor hypoxia is expected to contribute to the improvement of cancer treatment.
Our goal in this research is to develop nanodiamond imaging probes that can detect hypoxia in tumors with high sensitivity .
Here, we take full advantage of the excellent photostability of fluorescent nanodiamonds, to perform fundamental in vivo
evaluations of 50-100 nm surface-modified diamond nanoparticles, which are the basic for creating hypoxia probes. We
evaluated their fluorescence sensitivity upon in vivo administration (intratumoral, subcutaneous, and intravenous) in mice.
Polyglycerol hydrophilically modified 100-nm nanodiamond particles were found to be the most sensitive for fluorescence
detection among the particles evaluated, and thus will be used as a base material to create sensor probes that detects hypoxic
cells using the cellular oxygen sensor function. Such probes are expected to contribute to early detection of hypoxic diseases
including malignant tumors.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0120330644.

Tables and Figures

FIG. 1. Representative images of mice with hypoxic tumors(top: bioluminescence) and nanodiamond particles injected
into tumor (bottom: fluorescence).

FIG. 2. In vivo fluorescence image of subcutaneously
injected surface-modified nanodiamond particles.

FIG. 3. In vivo fluorescence image of 100-nm nanodiamondparticles with polyglycerol hydrophilic modification at theindicated time points after subcutaneous injection of theparticles.

Reference1

M. H. Alkahtani et al., Nanophotonics, 7, 1423-1453 (2018)
M. Fujiwara et al., Sci. Adv., 6, 37 (2020).
3
T. Fujisaku et al., ACS Nano, 13, 11726-11732 (2019)4
V. Petrova et al., Oncogenesis, 7, 10 (2018)2

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-10Detection of heat generation from biological systemusing double quantum thermometry
Hitoshi Ishiwata1, Kano Suzuki2, Kiichi Kaminaga1, Takeshi Murata2, Ryuji Igarashi1
1
QST, Institute for Quantum Life Science,2
Graduate School of Science and Membrane
Protein Research and Molecular Chirality Research Centers,
Chiba University
ishiwata.hitoshi@qst.go.jp
Introduction
The NV center in a diamond is a quantum sensor with exceptional quality for highly sensitive thermometry. For
quantification of heat generation from biological system, thermometry technique that allows to quantify accuracy andprecision of temperature is necessary. While many biological applications have been demonstrated by detection of CWODMR spectrum from NV center, it is difficult to quantify accuracy and precision of temperature measurement from peakfitting of CW ODMR spectrum. In this talk, we utilized all three energy levels |0>, |±1> of NV center to perform Double
Quantum Thermometry for highly sensitive and accurate measurement of temperature. Advantage of biological heat
detection using double quantum thermometry will be discussed in the talk.

ResultFIG. 1. Double Quantum thermometry using NV center indiamond.

FIG.1 shows typical result of Double Quantum
Thermometry by Thermal Echo measurement using
NV center in diamond. The energy difference between
the bright |0〉 and dark |± 1〉 states were observed as an
oscillation in the Thermal Echo signal. Inset of Figure
1 shows pulse sequence used for Thermal Echomeasurement.
Change in oscillation frequency of Thermal Echomeasurement was observed for different value ofapplied microwave frequency. As difference between
applied frequency and D(T) changed from 2 MHz, 2.5
MHz, 3 MHz, oscillation was observed at frequency of
2MHz, 2.5MHz, 3MHz respectively. Analysis ofoscillation frequency showed temperature precision of
0.3K, demonstrating sub-degree temperature precision
for measurement of biological temperature.
Application of quantum thermometry with highprecision will be discussed in the talk.

Reference:
This research was supported by MEXT Quantum Leap Flagship Program (MEXT Q-LEAP) Grant Number
JPMXS0120330644.

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-115The Anomalous Formation of Irradiation Induced Nitrogen-Vacancy Centersin 5-Nanometer-Sized Detonation Nanodiamonds
Frederick T.-K. So1,2,3, Alexander I. Shames4, Daiki Terada2,3, Takuya Genjo2,3, Hiroki Morishita1,
Izuru Ohki1, Takeshi Ohshima5, Shinobu Onoda5, Hideaki Takashima6, Shigeki Takeuchi6, Norikazu
Mizuochi1, Ryuji Igarashi3,7, Masahiro Shirakawa2,3*, Takuya F. Segawa2,8*1

Institute for Chemical Research, Kyoto University
Department of Molecular Engineering, Graduate School of Engineering, Kyoto University
3
Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology
4
Department of Physics, Ben-Gurion University of the Negev, Israel
5
Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology
6
Department of Electronic Science and Engineering, Kyoto University
7
National Institute for Radiological Sciences, National Institutes for Quantum Science and Technology
8
Laboratory for Solid State Physics, ETH Zurich, Switzerland
so.kit.58a@st.kyoto-u.ac.jp
2

Introduction
Nanodiamonds containing negatively charged nitrogen-vacancy (NV–) centers are versatile room-temperature
quantum sensors in a growing field of research. Yet, knowledge regarding the NV– formation mechanism in very small
particles is still limited. This study focuses on the formation of the smallest NV–-containing diamonds, 5 nm detonation
nanodiamonds (DNDs). As a reliable method to quantify NV– centers in nanodiamonds, half-field signals in electron
paramagnetic resonance (EPR) spectroscopy are recorded. By comparing the NV– concentration with a series of
nanodiamonds from high-pressure high-temperature (HPHT) synthesis (10–100 nm), it is shown that the formation
process in 5 nm DNDs is unique in several aspects. NV– centers in DNDs are already formed at the stage of electron
irradiation, without the need for high-temperature annealing, an effect related to the very small particle size. Also, theNV– concentration (in atomic ratio) in 5 nm DNDs surpasses that of 20 nm-sized nanodiamonds, which contradicts theobservation that the NV– concentration generally increases with particle size. This can be explained by the 10 times
higher concentration of substitutional nitrogen atoms in the studied DNDs ([NS ≈ 1000 ppm]) compared to the HPHT
nanodiamonds ([NS ≈ 100 ppm]). Upon electron irradiation at a fluence of 1.5 × 1019 e–/cm2, DNDs show a 12.5-foldincrement in the NV– concentration with no sign of saturation reaching 1 out of about 80 DNDs containing an NV–
center. These findings can be of interest for the creation of defects in other very small semiconductor nanoparticles
beyond NV-nanodiamonds as quantum sensors.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0120330644 & JPMXS0118067395,
KAKENHI (Grants 20H00453, 18K19297 and 21H04444)

MethodFigure 1. (a) Continuouswave HF EPR spectra (ν =9.87* GHz) of electronirradiated (2 MeV, 5 × 1018
e−/cm2) NDs with different
particle sizes after hightemperature annealing. The
double integral of the signal atgeff = 4.23 provides the NV−
concentration. (b) A summarygraph of NV− content (ppm, inunits of atomic ratio) in NDs of different sizes, measured via the HF EPR technique. Blue bars are the pristine NDs, orange
bars are the electron-irradiated NDs, and yellow bars are the electron-irradiated and subsequently annealed NDs (derived
from the geff = 4.23 signal in the EPR spectrum of panel a). Electron irradiation was conducted with 2 MeV electrons at afluence of 5 × 1018 e−/cm2. Annealing was performed at 800 °C in vacuum for 2 h. All samples were boiling acid treated at
130 °C for 3 days to remove Fe3+ impurities, which overlap with the HF EPR NV− signal. Inset table shows the corresponding
NV− concentrations in ppm. Errors in NV− concentration do not exceed ±15%.

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α1-12
Microwave antenna architecture for quantitative prediction of ODMR signals
Keisuke Oshimi1*, Masazumi Fujiwara1
1

Grad. Sch. Natural Science and Technology, Okayama University*pcfw97je@s.okayama-u.ac.jp

Introduction
Quantum sensing with fluorescent nanodiamonds (NDs) containing nitrogen-vacancy (NV) centers is performed under
the fluorescence microscope with microwave irradiation. It reads a modulation of optically detected magnetic resonance(ODMR) of electron spins of NV centers. This technique and the low cytotoxicity and biocompatibility of NDs enable tomeasure physical quantities inside biological samples, such as electric field, magnetic field, and temperature. So far, several
antenna structures have been developed for microwave excitation and used in biological research [1-3]. Recently, we reported
a glass-based antenna device having millimeter-scale area of microwave irradiation [4]. In this work, we demonstrate thequantitative prediction of the ODMR on our antenna devices, by thoroughly studying the relationship between the antenna
properties and ODMR contrast.
MethodWe quantitatively predict ODMR contrast on the glass surface of the antenna chip device developed for ODMR
measurements in biological samples (FIG. 1(a)). As shown in FIG. 1(b), we first simulated the microwave magnetic field(|B|) in the ODMR measurable area (sample detection area) by numerical simulation based on the finite element method,
considering the microwave reflection and transmission of chip devices and microwave components (cables, RF switches,
and amplifier). We next converted the simulated |B| to ODMR contrast of NDs using a theoretical equation based on
rotational Bloch equations [5]. For the comparison of this theoretical ODMR with the experimental results, we overlaid thetheoretical curve, as shown in FIG. 1(c). We found theoretical results closely matched the experimental results, whichindicates experimental ODMR measurements are predictable by the numerical simulation at the stage of design development.
In the presentation, we explain about the development methodology, and the future biological application of ND-based
quantum sensing.
This work was supported by the Nanotechnology Platform Project (Nanotechnology Open Facilities in Osaka University) of
MEXT (JPMXP09F21OS0055), JSPS-KAKENHI (19K21935, 20H00335, 20KK0317), AMED (JP21zf0127004), JST(JPMJMI21G1), the MEXT-LEADER program, the Mazda Foundation, and Osaka City University Strategic Research Grant
2017–2020, MEXT Quantum Leap Flagship Program (MEXT Q-LEAP, JPMXS0120330644).
(a)

(b)

(c)

1.0

B [G]

0.8
0.6
0.4
0.2
0.0

PL [a.u.]

1.00

1 mm
0

|B| [G]

0.4

0.95
0.90
0.85
0.80
0.75

0

200

400

600

800

y-coordinate [μm]FIG. 1 (a) Photograph of an antenna chip device. (b) The computed spatial distribution of |B| at 2.87 GHz on thechip surface. (c) Position dependence of the simulated |B| (top; blue line) and measured ODMR depth (bottom;
black squares) with the line calculated from the simulated |B| (bottom; red line).

Reference
1Yukawa et al., Nanoscale Adv., 2, 1859 (2020). 2J. Choi et al., PNAS, 117, 14636 (2020). 3R. Igarashi et al.,J. Am. Chem. Soc., 142, 7542 (2020). 4 Oshimi, Nishimura, Matsubara, Tanaka, Shikoh, Zhao, Zou, Komatsu,
Ikado, Takezawa, Kage-Nakadai, Izutsu, Yoshizato, Morita, Tokunaga, Yukawa, Baba, Teki and Fujiwara,
Lab Chip, 22, 2519 (2022). 5A. Dréau et al., Phys. Rev. B, 84, 195204 (2011).

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-01
An Artificial Intelligence Nanopore Platform Detects Omicron SARS-CoV-2 in clinical samples
Kaoru Murakami1,2, Shimpei Kubota1,2, Keiichiro Akabane1, Kumiko Tanaka1, Rigel Suzuki3, Yuta
Shinohara1, Hiroyasu Takei4, Shigeru Hashimoto1, Yuki Tanaka2, Shintaro Hojyo1,2, Kazuki Sato1,6,
Yuichi Kojima1,6, Masateru Taniguchi5*, and Masaaki Murakami1,2,12*

1) Molecular Psychoimmunology, Institute for Genetic Medicine, Graduate School of Medicine, Hokkaido
University, Sapporo 060-0815, Japan
2) Group of Quantum immunology, Institute for Quantum Life Science, National Institute for Quantum andRadiological Science and Technology (QST), Chiba 263-8555, Japan
3) Department of Microbiology and Immunology, Graduate School of Medicine, Hokkaido University, Sapporo,
060-0815, Japan.
4) Aipore Inc., 26-1 Sakuragaokacho, Shibuya, Tokyo 150-8512, Japan.
5) The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, 567-0047, Osaka, Japan.
6) Department of Hematology, Faculty of Medicine, Hokkaido University, Sapporo, 060-8638, Japan

Abstract
We recently reported a highly accurate, cost-effective artificial intelligence nanopore platform (AInanopore platform) to detect coronaviruses, including Wuhan SARS-CoV-2 within five minutes.
We here show that this platform can further distinguish SARS-CoV-2 alfa, beta, gamma, delta, andomicron variants. Moreover, it identified mutated Wuhan SARS-CoV-2 expressing the spike
proteins of the delta and omicron variants. Furthermore, we identified the omicron variant with asensitivity of 100% and specificity of over 94% in saliva specimens isolated from COVID-19
patients, which is the similar and/or better values to RT-PCR. Importantly, AI-nanopore platform
can identify even low concentrations of omicron variants with both sensitivity and specificity ofover 95% in saliva specimens, which had more than 30 Ct values of RT-PCR analysis and are hard
to be evaluated by RT-PCR, suggesting that the platform has an advantage over RT-PCR analysis.
Thus, this AI-nanopore platform may be an effective diagnostic tool for emerging infectious
pathogens including SARS-CoV-2 in clinical situation.
Rationale:
We recently reported an artificial intelligence (AI)-nanopore platform that enables testing for Wuhan
SARS-CoV-2 with high sensitivity and specificity. However, which parts of SARS-CoV-2, whether
mutated SARS-CoV-2 variants, or clinical samples with low concentration of virus are recognizedby the AI-nanopore platform are unknown.
Objectives:
To investigate these three questions.

Methods:
We analyzed cultured SARS-CoV-2 alpha, beta, gamma, delta, and omicron variants using an
improved AI-nanopore platform. To identify the specific SARS-CoV-2 structures detected by theplatform, we prepared mutated Wuhan variant SARS-CoV-2 expressing the spike proteins of the deltaor omicron variants. Additionally, we analyzed 241 saliva samples with omicron variants collectedfrom 132 infected and 109 uninfected people based on RT-PCR results using the platform.
Measurements and Main Results:
The platform distinguished cultured SARS-CoV-2 the five variantsand the mutated Wuhan variant,suggesting the platform’s sensitivity for the spike protein. Furthermore, it identified omicron SARSCoV-2 with a sensitivity of over 100% and specificity of over 94% from saliva specimens isolated
from COVID-19 patients. Moreover, the platform can identify even low concentrations of omicron
variants with both sensitivity and specificity of over 95% in saliva specimens, which are hard to beevaluated by RT-PCR.
Conclusions:
The AI-nanopore platform is an effective diagnostic tool for SARS-CoV-2 variants in clinical samples
even with low concentration virus.
Keywords: COVID-19 diagnosis, AI-nanopore, SARS-CoV-2 variants

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-024Non-equilibrium 𝜙 theory in a Hierarchy:
Towards Manipulating Holograms in Quantum Brain Dynamics
Akihiro Nishiyama1, Shigenori Tanaka1 and Jack A. Tuszynski2
1

Graduate School of System Informatics, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta, Canada T6G 1Z2

2

anishiyama@people.kobe-u.ac.jp
Introduction
We describe non-equilibrium 𝜙 4 theory in a hierarchical manner in order to develop a method for manipulating coherent
fields as a toy model of introducing control into Quantum Field Theory (QFT) of the brain, which is called Quantum Brain
Dynamics (QBD). We begin with the Lagrangian density of 𝜙 4 model, and derive the Klein--Gordon equation of coherent
fields with a damping term as an input--output equation proposed in areas of morphological computation or reservoir
computing. Our analysis is extended to QFT in a hierarchy representing multiple layers covering cortex in a brain. We findthat the desired target function is achieved via time-evolution in the Klein--Gordon Eqs. in a hierarchy of numericalsimulations when a signal in both the input and output prevails over noise in the intermediate layers. Our approach will beapplied to control coherent fields in the systems (in a hierarchy) described in the QFT framework, with potential applications
allowing to manipulate quantum fields, especially holograms in QBD.

FIG. 1. Quantum field 𝜙(𝑥) in a hierarchy.

FIG. 2. Distribution of evolving coherent field 𝜙(𝑥).

Acknowledgement
The present work was supported also by MEXT Quantum Leap Flagship Program (MEXT QLEAP)
Grant Number JPMXS0120330644.

Reference
1
Akihiro Nishiyama, Shigenori Tanaka, and Jack A. Tuszynski. Non-equilibrium Quantum Brain Dynamics II:
Formulation in 3+1 dimensions. Physica A: Statistical Mechanics and its Applications, 567:125706, 2021.
Akihiro Nishiyama, Shigenori Tanaka, and Jack A. Tuszynski. Quantum Brain Dynamics andHolography. Dynamics 2.2: 187-218, 2022.
2

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-03

Construction of dipeptide-based DNP-NMR molecular probe library focusing on
kidney injury mouse model
Yuki Aketa1, Yutaro Saito1, Fuminori Hyodo2, Masayuki Matsuo3 and Shinsuke Sando1,4
1

Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Japan2
Department of Radiology, Frontier Science for Imaging, School of Medicine, Gifu University, Japan3
Department of Radiology, School of Medicine, Gifu University, Japan
4
Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, Japan

Introduction
Dissolution dynamic nuclear polarization (dDNP) is a powerful technique that dramatically enhances the sensitivity ofmolecular probes in nuclear magnetic resonance imaging (NMR/MRI), which allows non-invasive detection of NMR/MRI
signals in a deep site of the body with high sensitivity1,2. Molecular probes hyperpolarized with dDNP have been successfully
applied for metabolic imaging in vivo and have been expected to have medical applications such as disease diagnosis andassessment of drug treatment2,3. Although various DNP-NMR molecular probes have been developed4, a limited number ofbiomarkers, usually well-studied enzymes, have been targeted despite the enormous number of potentially targetable
enzymes expressed in vivo. This situation is mainly due to the paucity of enzymes known to be associated with diseases. In
addition, it is unclear which enzymatic activity is applicable to the diagnosis of diseases by DNP-MRI even if the enzymatic
activity can be detected in the biosamples. To expand the utility of DNP-NMR, it is desired to devise a new approach todiscover biomarker enzymes applicable to the disease diagnosis by DNP-NMR. To this end, we envisioned that it would bean effective strategy to compare the metabolic activity of diseased and healthy tissues for a compound library and discovermolecules with disease-specific activity. We focused on exopeptidase which cleaves N- or C-terminus peptide bonds in
peptides because they are known to be related to disease progression,5-7 and we selected dipeptides for the library because
they could be recognized from two types of exopeptidases, aminopeptidase and carboxypeptidase, at least.
In the present study, we designed dipeptide libraries targeting aminopeptidases and carboxypeptidases respectively andprepared 180 compounds of the dipeptide libraries in total. Finally, we carried out a screening assay with the dipeptide
libraries in the kidney injury mouse model. In this presentation, we will show the design strategy for the dipeptide libraries
and the screening results.

Tables and Figures

Figure. 1. Strategy for discovering new biomarkers in this study.

Reference
1

J. H. Ardenkjær-Larsen et al., Proc. Natl. Acad. Sci. U. S. A. 100, 10158–10163 (2003).
K. Golman et al., Proc. Natl. Acad. Sci. U. S. A. 103, 11270–11275 (2006).
3
S. E. Day et al., Nat. Med. 13, 1382–1387 (2007).
4
Y. Kondo et al., Angew. Chem. Int. Ed. 60, 2–23 (2021).
5
L. Guzman-Rojas et al., Proc. Natl. Acad. Sci. U. S. A. 109, 1637–1642 (2012).
6
D. A. Silver et al., Clin. Cancer Res. 3, 81–85 (1997).
7
P. Selvakuamar et al., Clin. Cancer Res. 10, 2771–2775 (2004).
2

This work was supported by MEXT Quantum Leap Flagship Program (MEXT Q-LEAP) Grant Number JPMXS0120330644.

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-04

Nuclear hyperpolarization of liquid water by using photoexcited triplet electrons
in organic nanocrystals
Naoto Matsumoto1, Koki Nishimura1, Nobuo Kimizuka1, Yusuke Nishiyama2,3, Kenichiro Tateishi4,
Tomohiro Uesaka4, Nobuhiro Yanai1,51Department of Applied Chemistry, Graduate School of Engineering, Center for Molecular Systems, Kyushu
University,
2
NanoCrystallography Unit, RIKEN-JEOL Collaboration Center, 3JEOL RESONANCE Inc.,
4
Cluster for Pioneering Research, RIKEN, RIKEN Nishina Center for Accelerator-Based Science,
5
FOREST, JSTyanai@mail.cstm.kyushu-u.ac.jp

Introduction
Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are powerful methods to analyze molecular
structures and diagnose diseases. However, the sensitivity of NMR/MRI is quite low because of the low nuclear spinpolarization. Dynamic nuclear polarization (DNP) can improve the sensitivity of NMR/MRI by transferring highly polarized
electron spins to nuclear spins. On the other hand, the DNP using radical electrons uses electron polarization in thermal
equilibrium, which requires cryogenic temperatures (~4 K) to obtain high polarization.
Recently, DNP using photoexcited triplet electrons (triplet-DNP) has attracted much attention (FIG. 1).1 In triplet-DNP,
the use of non-equilibrium electron polarization allows nuclear hyperpolarization even at room temperature. However,polarizable targets have been limited to solid samples because polarization transfer from electrons to nuclei requires strong
dipole interactions.2 Towards the biological application, the hyperpolarization of liquid water has remained an important
challenge. In this work, we demonstrated the first hyperpolarization of liquid water by triplet-DNP.3

FIG. 1. Schematic representation of triplet-DNP.

Results and discussion
The hyperpolarization of liquid water in triplet-DNP requires polarization transfer from crystals to water, and it isimportant to increase the surface area of crystals. We prepared 3 sizes of nanocrystals, 390, 270, and 170 nm, respectively,by reprecipitation method and each sample was named NC390, NC270, and NC170, respectively. Triplet-DNP experiments with
mixtures of nanocrystals and water showed 1HNMR signal enhancement not only crystals but
also water (FIG. 2a). 1H-NMR enhancement ofwater was increased by decreasing the size ofnanocrystals, indicating that hyperpolarization ofwater was derived from nanocrystals (FIG. 2b).
Some control experiments and simulations
revealed a scenario of water hyperpolarization inwhich polarization of photoexcited triplet electron
was transferred to nuclear spins in the
FIG. 2. (a) 1H-NMR spectra of thermal (black) and after triplet-DNP
nanocrystals, and then transferred to liquid water for 120 s (green) at 28.2 MHz. (b) Nanocrystal size dependent 1Hat the nanocrystals-water interfaces.
NMR enhancement of water.

Reference
1

A. Henstra et al., Chem. Phys. Lett., 165, 6 (1990).
K. Nishimura et al., Chem. Commun., 56, 7217 (2020)
3
N. Matsumoto et al., J. Am. Chem. Soc., 144, 18023 (2022)2

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-05

Development of Polarizing Agent with Controlled Electronic Structure forHighly Efficient triplet-DNP
Keita Sakamoto1, Tomoyuki Hamachi1, Kenichiro Tateishi2, Tomohiro Uesaka2,
Nobuo Kimizuka1,3, Nobuhiro Yanai1,3,4
1

Department of Applied Chemistry, Graduate School of Engineering, Kyushu University
2

RIKEN Nishina Center for Accelerator-Based Science

3

Center for Molecular Systems (CMS) Kyushu University
4

FOREST, Japan Science and Technology Agency
yanai@mail.cstm.kyushu-u.ac.jp

Introduction
Dynamic nuclear polarization using photo-excited triplet electron (triplet-DNP) achieves the nuclear
hyperpolarization by transferring polarization from triplet electron spins to nuclear spins. However, it hasremained difficult to attain large nuclear polarization in amorphous materials of practical importance. Thisis due to the broadening of ESR spectra of the triplet state by the random orientation of the polarizing
agents and the anisotropic interaction of the electron spins. While the ESR spectra can be sharpened bycontrolling the orientation of the polarizing agents within a single crystal,1,2 the target molecules cannot be
incorporated into the single crystal. Therefore, instead of such “orientation control”, this study aims to
sharpen the ESR spectra and improve the DNP efficiency by "molecular design" focusing on the electronic
structure of polarizing agents.

MethodThe shape of the ESR spectra is determined by the zero-field splitting
parameters (D, E), which reflect the electronic structure of the excited triplet
state. When the electrons are symmetrically delocalized, the values of |D|and |E| become smaller and the ESR spectrum becomes sharper. In order toobtain such delocalized electronic structures, we have synthesized 6,13di(thiophen-2-yl)pentacene) (DTP) by introducing a thienyl group, a fivemembered ring with small steric hindrance, into pentacene, and evaluatedits electronic structure and polarization performance (FIG 1).
FIG. 1 Chemical structures ofTime-resolved ESR measurements of pentacene and DTP were
pentacene and DTP
conducted in a β-estradiol glass matrix. Compared to pentacene, DTP
showed more intense and sharper ESR signal thanks to their smaller |D| and|E| values (FIG. 2a).
The triplet-DNP experiment was
conducted with an integrated solid effectsequence. o-Terphenyl (OTPh) was
employed as the amorphous matrix.
FIG. 2b shows the buildup curve of 1H
NMR signal intensity after triplet DNP
at 120 K. For triplet-DNP with DTP, thefinal polarization after 5 min reached
0.83%, about three times higher thanthat with pentacene. Triplet-DNP ofpartially deuterated OTP ([D14]OTP : FIG. 2 (a) ESR spectra and, (b) buildup curve of 1H NMR signal Intensity.
OTP = 90 : 10 wt% (OTPd)) with DTP
resulted in the polarization of 7.5%,which was much higher than the previous highest value of 1.5%.3
Reference
1

Takeda. K, Triplet State Dynamic Nuclear Polarization (VDM, Saarbrücken, Germany, 2009).
Tateishi. K, et al., Proc. Natl. Acad. Sci. U. S. A, 111, 7527–7530 (2014).
3
Tateishi. K, et al., Angew. Chem. Int. Ed,52, 13307-13310 (2013).
2

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-06

DNP-NMR molecular probe for the detection of
Dipeptidyl peptidase-4 activity in vivo
Akihito Goto1, Hiroyuki Yatabe1, Kazutoshi Yamamoto2, Murali C. Krishna2, Yutaro Saito1, andShinsuke Sando1
1

Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo
2
National Institute of Health, USA
goto-akihito0528@g.ecc.u-tokyo.ac.jp

Introduction
Dipeptidyl peptidase-4 (DPP-4) is a peptidase that cleaves peptides at the second residues from the N-terminal terminus,
preferentially when the second residue is proline or alanine (Figure 1). Because DPP-4 is related to various diseases such astype 2 diabetes and cancers, DPP-4 is a potential therapeutic target and biomarker1,2. Thus, the detection of DPP-4 activity
in vivo will be a powerful technique for diagnosis.
Nuclear magnetic resonance imaging (NMR/MRI) is an imaging method that can observe and visualize the dynamics ofmolecular targets deep inside the body at high spatiotemporal resolution. In the medical field, however, the observation
targets are limited to 1H nuclei of water or lipids abundant in the body. This is due to the low sensitivity of NMR. Dynamic
nuclear polarization (DNP) can solve this problem by enhancing NMR sensitivity as much as 103–105 times. DNP is achievedby irradiating microwave to probes in the presence of stable radicals at a cryogenic temperature under high magnetic field totransfer polarization of electron spins to nuclear spins3. DNP-NMR molecular probes are required to satisfy the following
requirements: (1) sufficient length of spin-lattice relaxation time correlated with hyperpolarized lifetime, (2) sufficiently
large chemical shift change to distinguish a molecular probe and a product, (3) fast reaction with targets, and (4) selective
reaction with targets (Figure 2).
In this study, we attempted to develop a DNP-NMR molecular probe for the detection of DPP-4 activity in vivo bydesigning the molecular structure to satisfy these requirements. In the presentation, we will show the design strategy and therecent results.

Tables and Figures

Figure 1. DPP-4 and preferential cleavage site.

Figure 2. Requirements for DNP-NMR molecular probes.

References
1

C. F. Decon, Front. Endocrinol. 10, 80 (2019).
K. Ohnuma et al., Front. Biosci. 23, 1754–1779 (2018).
3
J. H. Ardenkjaer-Larsen et al., Proc. Natl. Acad. Sci. U. S. A. 100, 10158–10163 (2003).
2

This work was supported by MEXT Q-LEAP Grant Number JPMXS0120330644

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-07

Generation of polarized triplet electron spins at solid-liquid interfaces
Reiya Yabuki1, Tomoyuki Hamachi1, Koki Nishimura1, Kenichiro Tateishi2, Tomohiro Uesaka2 andNobuhiro Yanai1,3,4
1

Department of Applied Chemistry, Graduate School of Engineering, Kyushu University
2

RIKEN Nishina Center for Accelerator-Based Science
3
4

Center for Molecular System, Kyushu University

FOREST, Japan Science and Technology Agency
yanai@mail.cstm.kyushu-u.ac.jp

Introduction
Triplet-DNP can enhance NMR sensitivity at room temperature utilizing the electron polarization of the triplet state 1,2.
However, it has been difficult to enhance the solution NMR signal by triplet-DNP due to the immediate relaxation ofpolarized triplet electron spins in solution. Towards the direct polarization of solution by triplet-DNP, we aim for thegeneration of polarized triplet electron spins at solid-liquid interfaces.

MethodIn this study, we used tetrakis (4-carboxyphenyl) porphyrin (TCPP, FIG.
1a) as a polarization agent and aminopropyl silica gel (ASg, FIG. 1b) as a

(a

(b)

solid support. TCPP-modified ASg was dispersed in toluene. We evaluatedwhether polarized electron spins of triplet states are generated at the solidliquid interface by time-resolved ESR measurements.
Under pulsed laser excitation at 527 nm, ESR spectrum and the peak
decay of TCPP on ASg surface in toluene were measured. The ESR spectrum

FIG. 1. Chemical structures of(a) TCPP and (b) ASg

showed a characteristic line shape of the spin-polarized triplet state of TCPP3(FIG. 2). Furthermore, the lifetime of the spin-polarized state wasapproximately 3.0 μs, which was long enough to carry out the triplet-DNP
measurement. This result indicates that the use of solid support suppressed the
dynamics of the polarization agents and the relaxation of electron spinpolarization at the solid-liquid interface.

Reference
1

W. T. Wenckebach et al., Chem. Phys. Lett., 165, 6-10 (1990)

2

N. Yanai et al., J. Phys. Chem. Lett., 10, 2645-2650 (2021)

3

L. Bolzonello et al., Phys. Chem. Chem. Phys., 19, 27173-27177 (2017)

FIG. 2. ESR spectrum of
TCPP-ASg in tolueneProc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-08

Photoreaction study of a primate blue-light sensitive photoreceptor using
vibrational spectroscopy
Yosuke Mizuno1, Kota Katayama1, Hiroo Imai2, and Hideki Kandori1
1

2

Graduate School of Engineering, Nagoya Institute of Technology
Center for the Evolutionary Origins of Human Behavior, Kyoto University
y.mizuno.092@stn.nitech.ac.jp

Introduction
Photoreceptor proteins are expressed in eyes and function as vision systems. There are two types of photoreceptors. One
is rhodopsin which responsible for twilight vision, another one is cone pigments which responsible for color vision. These
proteins commonly bound 11-cis-retinal as a chromophore. Retinal absorb UV light (370 nm) in the solution and absorb
about 440 nm by making Schiff base linkage. Further, protein moiety determines the absorption range from UV to red light1.
The photoreaction mechanisms and structural information were well known in rhodopsin. However, Cone pigment havebeen less known than rhodopsin because of low expression level and handling difficulty. We previously observed the firststructural data of the primary Batho intermediate state of primate red (MR), green (MG) and blue (MB) cone pigments by
low-temperature FTIR spectroscopy 2. Recently, we also reported the structural study of BL intermediate in MB which isformed from initial photointermediate 3. Here, we extended these vibrational structural studies by identifying subsequent
photointermediate of cone pigments, especially MB.
Results
By using low-temperature UV−visible spectroscopy, we found that the Lumi intermediate (223K) of MB formed intransition from the BL intermediate (163K) shows an absorption maximum in the UV region (Fig.1), indicating the
deprotonation of the retinal Schiff base. Comparison of the light-induced difference FTIR spectra of Batho (77K), BL, andLumi showed significant α-helical backbone C=O stretching (1661 and 1652 cm-1) and protonated carboxylate C=O
stretching vibrations (1714 and 1712 cm-1) only in the Lumi intermediate (Fig.2). Thus, the transition from BL to Lumi
involves dramatic changes in protein environment with a proton transfer reaction between the Schiff base and the counterion
resulting in an absorption maximum in the UV region4.

Tables and Figures

FIG.1. UV-visible absorption spectra of MB (left) andlight-induced difference spectra (right) with >430 nm illumination(solid line) and 360 nm illumination (dash line) at 223K

FIG.2. Light-minus-dark difference FTIR spectra of MB at 223, 163,
and 77 K in the 1780−1600 cm−1 region. Spectra were measured in
H2O (black) and D2O (red).

Reference
1

O.P. Ernst et al., Chem Rev, 114, 126-163 (2014).
K. Katayama et al., Sci Rep, 7, 4904 (2017).
3
S. Hanai et al., Biophys Physicobiol, 18, 40-49 (2021).
4
Mizuno et al., Biochemistry, in press2

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-09

Novel photoisomerization reaction innear-infrared light absorbing enzymerhodopsins
Masahiro Sugiura1*, Kazuki Ishikawa1, Kota Katayama1,2, Yuji Sumii1, Rei Abe-Yoshizumi1,
Satoshi P. Tsunoda1,2, Yuji Furutani1,2, Norio Shibata1, Leonid S. Brown3, Hideki Kandori1,2**
1

Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Japan
2
OptoBioTechnology Research Center, Nagoya Institute of Technology, Japan3
Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Canada*: m.sugiura.734@stn.nitech.ac.jp, **: kandori@nitech.ac.jp
Introduction
Rhodopsins is a large family of retinal-binding photoreceptive membraneproteins found in microbes and animals 1. Microbial rhodopsins has different
functional family, including light-driven ion pumps, light-gated ion channels,
light sensors, and light-activated enzymes (FIG.1). Microbial rhodopsins
possess retinal chromophores that capture light energy and isomerize from alltrans to 13-cis (FIG.1). Although this isomerization reaction was universallyconserved in microbial rhodopsins, a recently discovered microbial rhodopsin,
bestrhodopsin, offered surprising photochemical properties.
Bestrhodopsin is a far-red light absorbing novel microbial rhodopsin, in
which one or two rhodopsin domains are fused to a bestrophin channel andfunction as light-gated ion channels 2. The surprises were that bestrhodopsin
performs an all-trans to 11-cis photoisomerization and it show no photoreaction FIG.1 Functions and photoisomerization
at low temperatures at <170K, despite any microbial rhodopsin can react 2.
of microbial rhodopsin
Our target protein is enzymerhodopsin (NeoR) which was reported in 2020 3.
This NeoR is similar to besrhodopsin in the following four points 3. First, it absorbs far-red and near infra-red light. Second,
the rhodopsin domain forms heterodimers. Third, it has eight transmembrane α-helices whereas normal rhodopsin iscomposed of seven transmembrane α-helices. Finally, three carboxylic acids are conserved around the retinal as achromophore, different from normal microbial rhodopsins which have one or two carboxylic acids near the retinal. Despite
these similar properties between bestrhodopsin and NeoR, the detailed photochemical properties of NeoR remained unknown.
Thus, we clarified the photochemical properties of NeoR using HPLC and spectroscopy.

Results
We studied a novel near-infrared light-absorbing
enzymerhodopsin from Obelidium mucronatum (OmNeoR).
OmNeoR show guanylyl cyclase activity upon light irradiation,
when it form heterodimers. Using UV-vis spectroscopy, it isrevealed that OmNeoR absorbs near infrared light, and its
absorption wavelength converts the dark state into a stable UVabsorbing state.
Using HPLC analysis which can determine composition ratioof retinal isomers in rhodopsin, anti-oxime peak (X) is observed
different from f 13-cis, 11-cis, 9-cis, or all-trans form. In
previous research, peak (X) is probably 7-cis. However, 7-cis
FIG.2 Retinal isomerization in NeoR andretinal is unstable, because of a steric hindrance between the 9photoreaction at low temperature.
methyl group and methyls in the β-ionone ring. In addition, an
HPLC peak of di-cis retinal oxime, such as the 9,11-di-cis form, can appear between those of 9-cis and all-trans retinal oxime.
Thus we weren't sure if peak (X) was really 7-cis form. Here, we isolate same isomer as peak (X) and measure the 1H NMR
spectra which is consistent with 7-cis form. Therefore, we conclude that peak (X) is 7-cis retinal.
In addition, OmNeoR show no photoreaction at <270K. It indicate that there exist potential barrier for 7-cis isomerizationin excited state of OmNeoR.
In this presentation, we would like to discuss the unique photoisomerization reaction of NeoR.

Reference
1

O.P. Ernst et al., Chem Rev, 114, 126-163 (2014).
A. Rozenberg et al. Nat. Struct. Mol. Biol, 29, 592−603 (2022)
3
M. Broser et al. Nat.Commun. 11, 5682 (2020)2

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-10Development of a real-time 4D quantum temperature imaging system
to measure intercellular thermal diffusivity
Haruka Maeoka1, Ryuji Igarashi2, Shin Usuki3, and Takuma Sugi1
1

Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University
2
3

Quantum Science and Technology Organization

Research Institute of Electronics, Shizuoka University
m211518@hiroshima-u.ac.jp

Cellular function is severely affected by temperature change. Heat produced within a cell controls its own cellularfunction cell-autonomously and neighboring cells’ function non-cell-autonomously. While several studies havefocused on intracellular thermal diffusion, few have reported on how intercellular thermal diffusion influencesneighboring cells’ function. This question could be addressed by estimation of the intercellular thermal diffusivity,
which requires quantifications of temperatures at three-dimensionally distributed multiple cells during thermal
diffusion. However, assuming that the thermal diffusivity in cells is the same as that in water, 1.5×10-7 m2 / sec, ittakes 1 millisecond for heat to diffuse through multiple 10 μm cells in all XYZ directions. In contrast, when we takeimages using a 100 fps camera with 100 scans along Z-axis and 30 times data accumulations, current 3D imaging
technologies such as confocal microscopy take 50 milliseconds to measure temperature of multiple cells along Zaxis. This means that the measurement speed of the current technologies is insufficient to observe 3D intercellularheat diffusion which completes within 1 millisecond.
Recently, we developed the high-resolution light field microscopy (HR-LFM) capable of ‘scan-less’ 3D imaging
by capturing 3D space as a 2D image using a micro-lens array. We also focused on the fluorescent nanodiamonds(FNDs) which allow for highly sensitive temperature measurement. Here, these two cutting-edge technologies
inspired us to establish a system for measuring the temperatures of multiple cells with an acquisition rate faster thanheat diffusion rate. First, (1) we constructed a ‘selective imaging’ system to selectively extract the fluorescence of
only FNDs from among background fluorescence by irradiating microwave that induces electron spin resonance tomodulate the fluorescence of FNDs. Then, we synchronized ‘scan-less’ 3D detection of multiple signals by HRLFM with microwave irradiation. This enabled simultaneous selective extraction of multiple FNDs’ fluorescencefrom among fluorescent beads in a 3D sample and from among an autofluorescence in C. elegans, thereby achieving
3D selective imaging 50-fold faster than confocal microscopy. Second, (2) we attempted to establish the system formeasuring 3D heat diffusion. We successfully measured temperature changes at multiple 3D locations
simultaneously in nematode C. elegans, thus achieving 3D temperature imaging 100-fold faster than confocal
microscopy. Using this method, we will calculate the intercellular thermal diffusivity by measuring the intercellularheat diffusion from a heat source cell to neighboring cells in vivo.

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-11

Bidirectional neural network and its application toimage denoising, super-resolution, and image completion
Kei Majima1,2, Noriaki Yahata1
1

Institute for Quantum Life Science, National Institutes for Quantum Science and Technology (QST), Chiba, Japan
2

PRESTO, Japan Science and Technology Agency (JST), Japanmajima.kei@qst.go.jp

Introduction
Quantum sensing technology has enabled the development of new methods to visualize various physical parameters ofinterest in biological systems. For example, the concentration of specific molecules can be visualized by magnetic
resonance imaging (MRI), and an electromagnetic field or distribution of temperature can be reconstructed by nitrogenvacancy center sensing (NV-center sensing). Because observed image data are sometimes noisy/lowresolution/incomplete, image processing to recover clean/high-resolution/complete images from the observed ones is a
critical step that must be developed. In this report, we present a unified framework for the above-mentioned imageprocessing tasks using neural networks.

Methods
We describe our proposed framework by taking the super-resolution task as an example. Note that the same framework canalso be used for image denoising and image completion. In our framework, we assume that a set of low-resolution images
and the corresponding high-resolution images are available as training data. Then a bidirectional neural network, which is aneural network whose each layer is bidirectional, is trained using the training data (Fig 1A). Following the neural network
training, for new low-resolution images, the corresponding high-resolution images can be estimated using this neuralnetwork as a converter.

Results
Using two types of toy image data, we tested the proposed framework on three types of image-processing task: 1) image
denoising, 2) super-resolution, and 3) image completion. Results of the super-resolution task are shown in Fig. 1B and C.

FIG 1. Neural network-based image-preprocessing framework. A schematic of neural network
training (panel A) and results of the super-resolution task (panels B,C) are shown.

Discussion and Conclusions
In this report, we presented an image-processing framework using a bidirectional neural network, and our preliminary
results showed that this framework can effectively perform several types of image-processing task. The application to realexperimental data in the field of quantum sensing will be addressed in our future studies.

Acknowledgments
This research was supported by MEXT Q-LEAP (JPMXS0120330644), JSPS KAKENHI (20K16465), JST ERATO(JPMJER1801), and JST PRESTO (JPMJPR2128).

Proc. 5th IFQMS (The 5th International Forum on Quantum Metrology and Sensing)

SE-03B-α2-12

Molecular insight into photoactivation mechanism of BLUF protein
by QM/MM free energy simulation
Masahiko Taguchi, Shun Sakuraba, Justin Chan, and Hidetoshi Kono
Institute for Quantum Life Science, National Institutes for Quantum Science and Technology
taguchi.masahiko@qst.go.jp
Introduction
OaPAC is a photoactivated enzyme that forms a homodimer [1,2]. It has two BLUF photoreceptor domains
connected to the catalytic domains via long coiled-coil C-terminal helixes. It is thought that during
photoactivation, reorganization of hydrogen bonding network between Tyr6, Gln48, and chromophore andketo-enol tautomerization of Gln48 occur in the BLUF domain [3,4]. However, the free-energy profile of thephoto-isomerization reaction and how the structural change in the BLUF domain propagates toward thecatalytic domain have not been revealed yet.
MethodWe first focused on the BLUF domain dimer with the C-terminal helixes from the dark state X-ray
crystallographic structure of OaPAC [1]. We free-energetically optimized the dark state structure using
QM/MM RWFE-SCF method [5]. We considered two possible light state structures that were free-energetically
optimized. The free-energy differences between the dark and two light state structures were evaluated by thefree-energy perturbation calculation. To clarify differences in protein dynamics upon photo-isomerization, we
performed long-time MD simulations for the dark and light state structures.
Results
The free-energy difference between the two light state structures was estimated ~4.7 kcal/mol. The light statemodel with a lower free energy is consistent with a FTIR experiment result [4], but is inconsistent with lightstate X-ray crystallographic structure [2] in the assignment of nitrogen and oxygen atoms of Gln48 sidechain.
Our component analysis of free-energy difference between the dark and light state structures showed that thechemically unstable enol tautomer of Gln48 in the light state is stabilized by a strong hydrogen bonding
network with chromophore and Tyr6. Moreover, in the light state, we observed a flip of Trp90 nearby the Cterminal helix, causing the subsequent structural changes in the BLUF core and the C-terminal helix.
This work was supported by MEXT Q-LEAP Grant Number JPMXS0120330644.
References[1] M. Ohki et al., Proc. Natl. Acad. Sci. USA 113, 6659 (2016).
[2] M. Ohki et al., Proc. Natl. Acad. Sci. USA 114, 8562 (2017).
[3] T. Domratcheva et al., Sci. Rep. 6, 22669 (2016).
[4] T. Iwata et al., J. Am. Chem. Soc. 140, 11982 (2018).
[5] S. Hayashi et al., Annu. Rev. Phys. Chem. 68, 135 (2017).