Article
Biochemical Research Methods
Kathrin Aebischer, Matthias Ernst
Summary: A simple Hahn echo in a single-spin system can lead to echo modulations if the static Hamiltonian contains a component along the direction of the echo pulse. Experimental observations have shown that echo modulations can be explained by this model under homonuclear decoupling in solids. These modulations are significantly reduced using double-echo sequences as analyzed and observed.
JOURNAL OF MAGNETIC RESONANCE
(2023)
Article
Physics, Condensed Matter
Helen Chadwick, Joshua T. Cantin, Yosef Alkoby, Gil Alexandrowicz
Summary: The study discovers that there are four spin-echoes which need to be considered in helium (He-3) spin-echo measurements, and even in the case of elastic scattering, these additional echoes can lead to oscillations that could be mistakenly interpreted as being due to inelastic scattering. By propagating the He-3 through the measured magnetic field profile of the apparatus and considering the geometry of the machine, it is possible to accurately simulate the experimental data and separate the effect of these additional echoes from inelastic scattering events.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Neurosciences
Canhuang Luo, Sasskia Bruers, Isabelle Berry, Rufin VanRullen, Leila Reddy
Summary: The study investigates how visual information reverberates in the human brain in the form of perceptual echoes through a combination of EEG and fMRI recordings. The findings suggest that these echoes likely originate in early visual cortex, influenced by widespread activity in V1 and V2.
Article
Neurosciences
Alexander Zhigalov, Ole Jensen
Summary: Growing evidence suggests that travelling waves are functionally relevant for cognitive operations in the brain. In this study, the researchers examined the perceptual alpha-echo, which propagates as a travelling wave across the cortical surface. They found that the amplitude of the alpha-echo decayed with respect to the sensor distance, and the propagation latencies consistently increased with distance. These findings contribute to the understanding of cognitive processes in the brain.
Article
Biophysics
Jeff Snyder, Peter Seres, Alan H. Wilman
Summary: Three-dimensional fast spin echo imaging with long echo trains combines high resolution with reasonable acquisition times, reduced specific absorption rate, and low refocusing flip angles. The inclusion of selective pulse and spoiler gradients results in a signal-to-noise ratio (SNR) penalty for slab select excitation, and the SNR decreases further due to B1(+) variation and T2/T1 times. Therefore, choosing slab-selective excitation should consider the required SNR, chosen anatomy, and sequence restrictions.
NMR IN BIOMEDICINE
(2023)
Article
Nanoscience & Nanotechnology
Leon Zaporski, Noah Shofer, Jonathan H. Bodey, Santanu Manna, George Gillard, Martin Hayhurst Appel, Christian Schimpf, Saimon Filipe Covre da Silva, John Jarman, Geoffroy Delamare, Gunhee Park, Urs Haeusler, Evgeny A. Chekhovich, Armando Rastelli, Dorian A. Gangloff, Mete Atature, Claire Le Gall
Summary: Combining highly coherent spin control with efficient light-matter coupling, this study demonstrates the ability to decouple electron spin qubits in optically active semiconductor quantum dots beyond 0.113(3) ms, overcoming the limitations imposed by nuclear inhomogeneity. The findings show a promising solution to the material science challenge and establish the basis for highly coherent spin-photon interfaces.
NATURE NANOTECHNOLOGY
(2023)
Article
Environmental Sciences
Mingyue Lu, Yuchen Li, Manzhu Yu, Qian Zhang, Yadong Zhang, Bin Liu, Menglong Wang
Summary: Accurate and timely precipitation forecasts are important for decision-making, planning, and protecting lives and property. This research proposes a multisource ConvLSTM (MS-ConvLSTM) model that incorporates multiple data sources, including composite reflectivity, echo top, vertically integrated liquid water, and radar-retrieved wind field data, to improve the accuracy of precipitation forecasting. Experimental results showed that the proposed model outperformed traditional methods in terms of various evaluation metrics.
Article
Optics
Pu Wang, Lixin He, Yanqing He, Siqi Sun, Ruxuan Liu, Baoning Wang, Pengfei Lan, Peixiang Lu
Summary: In this study, we theoretically investigate the formation of high-order fractional alignment echo in OCS molecules and analyze the intricate dependence of echo intensity on laser conditions. Through analysis with rotational density matrix, we demonstrate that the complex dependence arises from interference of multiple quantum pathways involving multilevel rotational transitions. The results provide a comprehensive multilevel picture of quantum dynamics in molecular ensembles for the development of rotational echo spectroscopy.
Article
Environmental Sciences
Yupeng Teng, Tianyan Li, Shuqing Ma, Hongbin Chen
Summary: Through the study of the Chinese Doppler S-band Weather Radar (CINRAD/SA) in Beijing, it was found that more than half of the clear-air echoes at night are caused by atmospheric turbulence, unrelated to biological activity. Additionally, the reflecting-layers model was introduced to explain the diurnal variation and reflectivity characteristics of the echoes, indicating that turbulent mixing weakens the echo signal. Hence, re-evaluating the position of turbulence in clear-air echoes is necessary.
Article
Physics, Nuclear
Kai Lin, Wei-Liang Qian
Summary: This study investigates the echoes in axial gravitational perturbations in compact objects using an alternative scheme of the finite difference method implemented in two coordinate systems. The resulting ringdown waveforms in the black hole metric are split into reflected and transmitted waves as the initial perturbations evolve and collide with the peak of the effective potential. Quasinormal oscillations in compact stars might be characterized by echoes, produced by the gravitational waves bouncing between the divergent potential at the star's center and the peak of the effective potential. The implications of the present study are also discussed herein.
Article
Radiology, Nuclear Medicine & Medical Imaging
Guangyu Dan, Kaibao Sun, Qingfei Luo, Xiaohong Joe Zhou
Summary: This study developed a time-efficient pulse sequence that acquires multiple diffusion-weighted images with distinct diffusion times in a single shot. It was experimentally demonstrated on a diffusion phantom, a fruit, and healthy human brain and prostate. The technique offers a time-efficient tool for investigating the diffusion-time dependency in diffusion MRI studies.
MAGNETIC RESONANCE IN MEDICINE
(2023)
Article
Multidisciplinary Sciences
Wyatt Vine, Mykhailo Savytskyi, Arjen Vaartjes, Anders Kringhoj, Daniel Parker, James Slack-Smith, Thomas Schenkel, Klaus Molmer, Jeffrey C. McCallum, Brett C. Johnson, Andrea Morello, Jarryd J. Pla
Summary: The sensitivity of pulsed electron spin resonance (ESR) measurements has been greatly enhanced by using superconducting microresonators and quantum-limited Josephson parametric amplifiers, achieving an improvement of more than four orders of magnitude. Incompatibility between Josephson junction-based devices and magnetic fields has resulted in the design of separate microwave resonators and amplifiers, leading to complex spectrometers and technical barriers. However, by coupling an ensemble of spins directly to a weakly nonlinear and magnetic field-resilient superconducting microwave resonator, this issue is circumvented. Pulsed ESR measurements with amplification within the device are successfully performed, demonstrating a high sensitivity and potential for application under conventional ESR operating conditions.
Article
Meteorology & Atmospheric Sciences
Ang Zhou, Kun Zhao, Xin Xu, Qiqing Liu, Zhicheng Ding, Hao Huang, Xiantong Liu, Xiaona Rao, Sheng Hu
Summary: This study examines the characteristics of merger-formation bow echoes (MFBEs) and classical bow echoes (CBEs) over South China using radar observations. It is found that MFBEs account for 62% of the total bow echoes and mainly occur in the afternoon over coastal regions, while CBEs account for 38% and develop in the morning over mountainous areas. The proposed Merger-Classical index successfully distinguishes the environments for the development of MFBEs and CBEs, and MFBEs produce heavier rainfall near metropolitan areas.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Chemistry, Physical
David Guarin, Diego Carnevale, Mathieu Baudin, Philippe Pelupessy, Daniel Abergel, Geoffrey Bodenhausen
Summary: In this study, the buildup of proton polarization due to dynamic nuclear polarization (DNP) was monitored by observing echoes instead of FIDs. It was found that under DNP conditions, the proton coherence lifetime was extended, leading to transient surges in spin echo amplitudes.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Meteorology & Atmospheric Sciences
Shuai Zhang, Jinzhong Min, Chian Zhang, Xingyou Huang, Jun Liu, Kaihua Wei
Summary: This paper proposes a hybrid method for identifying second-trip echoes using phase modulation and polarimetric technology in pulse Doppler radars, which significantly reduces misidentification in regions of high turbulence and severe wind shear. Compared to existing methods, the hybrid approach demonstrates superior performance in independent test datasets, particularly in challenging meteorological conditions.
ADVANCES IN ATMOSPHERIC SCIENCES
(2021)
Article
Multidisciplinary Sciences
Shingo Sotoma, Daiki Terada, Takuya F. Segawa, Ryuji Igarashi, Yoshie Harada, Masahiro Shirakawa
SCIENTIFIC REPORTS
(2018)
Article
Chemistry, Multidisciplinary
Daiki Terada, Takuya F. Segawa, Alexander I. Shames, Shinobu Onoda, Takeshi Ohshima, Eiji Osawa, Ryuji Igarashi, Masahiro Shirakawa
Article
Biochemistry & Molecular Biology
Daiki Terada, Takuya Genjo, Takuya F. Segawa, Ryuji Igarashi, Masahiro Shirakawa
BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS
(2020)
Article
Chemistry, Multidisciplinary
Takahiro Fujisaku, Ryotaro Tanabe, Shinobu Onoda, Ryou Kubota, Takuya F. Segawa, Frederick T. -K. So, Takeshi Ohshima, Itaru Hamachi, Masahiro Shirakawa, Ryuji Igarashi
Article
Chemistry, Physical
Takuya F. Segawa, Alexander Shames
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2020)
Article
Materials Science, Multidisciplinary
Konosuke Shimazaki, Hiroki Kawaguchi, Hideaki Takashima, Takuya Fabian Segawa, Frederick T. -K. So, Daiki Terada, Shinobu Onoda, Takeshi Ohshima, Masahiro Shirakawa, Shigeki Takeuchi
Summary: SiV color centers are created in DNDs through annealing treatment in high vacuum up to 1100 degrees C. The precursor of the SiV centers is pristine silicon impurities inside the nanodiamond lattice. Electron irradiated DNDs before annealing show characteristic emission lines of SiV centers.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2021)
Editorial Material
Nanoscience & Nanotechnology
Takuya F. Segawa, Alexander I. Shames
ACS APPLIED NANO MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Dini Kurnia Ikliptikawati, Masaharu Hazawa, Frederick T-K So, Daiki Terada, Akiko Kobayashi, Takuya F. Segawa, Masahiro Shirakawa, Richard W. Wong
Summary: In this study, optical diffraction tomography was used to quantitatively analyze the morphological and biophysical properties of living cells treated with nanodiamonds of different sizes. The technique allowed for tracking of nanodiamond aggregation and deaggregation inside cells without the need for fluorescence labeling. The findings suggest that refractive index measurements are a promising tool for real-time tracking of nanodiamonds in living cells, potentially facilitating studies on therapeutic or metabolic activities with minimal laser irradiation.
DIAMOND AND RELATED MATERIALS
(2021)
Article
Chemistry, Physical
Frederick T. -K. So, Alexander I. Shames, Daiki Terada, Takuya Genjo, Hiroki Morishita, Izuru Ohki, Takeshi Ohshima, Shinobu Onoda, Hideaki Takashima, Shigeki Takeuchi, Norikazu Mizuochi, Ryuji Igarashi, Masahiro Shirakawa, Takuya F. Segawa
Summary: This study focuses on the formation mechanism of NV- centers in 5 nm detonation nanodiamonds (DNDs) and finds that it is different from high-pressure high-temperature synthesized nanodiamonds. The study also discovers that the NV- concentration in 5 nm DNDs exceeds that of 20 nm-sized nanodiamonds.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Dorothea Pinotsi, Rui Tian, Pratyush Anand, Koichiro Miyanishi, Jens M. Boss, Kevin Kai Chang, Pol Welter, Frederick T. -K. So, Daiki Terada, Ryuji Igarashi, Masahiro Shirakawa, Christian L. Degen, Takuya F. Segawa
Summary: In this study, 5 nanometer sized detonation nanodiamonds (DNDs) were investigated as potential single-particle labels for distance measurements in biomolecules. Nitrogen-vacancy (NV) defects in the crystal lattice could be detected through their fluorescence and optically-detected magnetic resonance (ODMR). Two complementary approaches based on spin-spin coupling or optical super-resolution imaging were proposed for single-particle distance measurements. The first approach focused on measuring the mutual magnetic dipole-dipole coupling between two NV centers in close DNDs using a pulse ODMR sequence, while the second approach successfully localized the NV centers in DNDs using STORM super-resolution imaging, enabling optical nanometer-scale single-particle distance measurements.
NANOSCALE ADVANCES
(2023)
Review
Chemistry, Physical
Takuya F. Segawa, Ryuji Igarashi
Summary: Nanodiamonds containing fluorescent Nitrogen-Vacancy (NV) centers can be used as nanoscale quantum sensors, capable of measuring various physical and chemical quantities by recording spectral shift or changes in relaxation rates using optically-detected magnetic resonance (ODMR). This review highlights the field of ODMR spectroscopy of NV-nanodiamonds and its applications in sensing different quantities, with a focus on biological applications.
PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY
(2023)
Article
Chemistry, Multidisciplinary
Gabriela R. Stadler, Takuya F. Segawa, Matthias Butikofer, Venita Decker, Sandra Loss, Barbara Czarniecki, Felix Torres, Roland Riek
Summary: Fragment-based drug design using high-field NMR as the screening method is expensive and complicated. This study proposes an alternative approach using cryogen-free 80 MHz benchtop NMR and photoinduced hyperpolarization to achieve high sensitivity and speed in hit discovery and drug design. The findings demonstrate the potential of benchtop NMR in near-physiological conditions for drug design and other life science applications.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Gabriela R. Stadler, Takuya F. Segawa, Matthias Buetikofer, Venita Decker, Sandra Loss, Barbara Czarniecki, Felix Torres, Roland Riek
Summary: Fragment-based drug design is a commonly used strategy in rational drug design. This study proposes an alternative approach to high-field NMR screening by utilizing a cryogen-free benchtop NMR spectrometer. The results show that it is possible to discover new hits and initiate drug design using this approach at low micromolar concentrations. Compared to high-field NMR, the benchtop NMR performs faster and has a lower limit of detection.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Daiki Terada, Frederick Tze Kit So, Bodo Hattendorf, Tamami Yanagi, Eiji Osawa, Norikazu Mizuochi, Masahiro Shirakawa, Ryuji Igarashi, Takuya Fabian Segawa
Summary: This paper presents a purely chemical deaggregation method for producing highly stable single-digit detonation nanodiamonds (DNDs) in a suspension. The method can be easily carried out in a standard chemistry laboratory with commonly available laboratory apparatus.
NANOSCALE ADVANCES
(2022)
Article
Materials Science, Multidisciplinary
M. Loretz, H. Takahashi, T. F. Segawa, J. M. Boss, C. L. Degen
