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Journal Articles

Upgrade of the small-angle neutron scattering diffractometer SANS-J at JRR-3

Kumada, Takayuki; Motokawa, Ryuhei; Oba, Yojiro; Nakagawa, Hiroshi; Sekine, Yurina; Micheau, C.; Ueda, Yuki; Sugita, Tsuyoshi; Birumachi, Atsushi; Sasaki, Miki; et al.

Journal of Applied Crystallography, 56(6), p.1776 - 1783, 2023/12

The combination of the existing position-sensitive photomultiplier and the 3He main detector with focusing devices, and the newly installed front detectors in SANS-J at JRR-3 covers small-angle neutron scattering signals in the range of the magnitude of the scattering vector Q from 0.002 to 6 nm-1 gaplessly with three standard device layouts. The installation of the front detector and a graphical user interface system largely improved the usability of SANS-J.

Journal Articles

Present status of JAEA-Tokai tandem accelerator

Kutsukake, Kenichi; Matsuda, Makoto; Nakamura, Masahiko; Ishizaki, Nobuhiro; Kabumoto, Hiroshi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Nakagawa, Sohei; Abe, Shinichi

Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1080 - 1084, 2023/11

no abstracts in English

Journal Articles

Modulating molecular interactions in extruded pea protein isolate

Muhialdin, B. J.*; Sanchez, C. F.*; Nakagawa, Hiroshi; Ubbink, J.*

Food Biophysics, 10 Pages, 2023/10

The impact of molecular interactions on the physical properties of extruded pea protein isolate (PPI) is investigated by adding interaction-modulating compounds to the matrix premix and studying the resulting variations in mechanical and physicochemical properties. Blends of PPI containing either sodium phosphate, urea, sodium dodecylsulphate and beta-mercaptoethanol, as well as with all four compounds and only with deionized water were extruded into thin strands using a lab-scale twin-screw extruder. The hardness from texture profile analysis was the lowest for matrices extruded with beta-mercaptoethanol and with all four chemicals, and highest for the control sample. The water holding capacity of the matrices is lowest for the beta-mercaptoethanol-containing matrix. Our results confirm the importance of disulfide bonds in texturized PPI and show that hydrophobic and electrostatic interactions play auxiliary roles in modulating the properties of extruded PPI matrices.

Journal Articles

Simultaneous SANS/FTIR measurement system incorporating the ATR sampling method

Kaneko, Fumitoshi*; Radulescu, A.*; Nakagawa, Hiroshi

Journal of Applied Crystallography, 56(5), p.1522 - 1527, 2023/10

Small angle neutron scattering (SANS) is widely used as a powerful technique to study the higher-order structure of soft matter. To increase the reliability of SANS profile analysis for complex, multi-component systems, combining different types of structural information obtained by other methods is desirable. A simultaneous measurement system combining SANS and Fourier transform infrared (FTIR) spectroscopy meets this objective and is particularly useful for targets for which it is difficult to match the timing of structural changes between experiments, but there is a problem that samples suitable for SANS are too thick for typical transmission FTIR measurements. To overcome this problem, a new simultaneous measurement system that employs the attenuated total reflection sampling method for FTIR spectroscopy has been developed.

Journal Articles

Effect of starch retrogradation on molecular dynamics of cooked rice by quasi-elastic neutron scattering

Hirata, Yoshinobu*; Nakagawa, Hiroshi; Yamauchi, Hiroki; Kaneko, Koji; Hagihara, Masato; Yamaguchi, Hideyuki*; Omoto, Chie*; Katsuno, Nakako*; Imaizumi, Teppei*; Nishizu, Takahisa*

Food Hydrocolloids, 141, p.108728_1 - 108728_7, 2023/08

Crystallinity is reflected in the mechanical properties of foods and materials. Crystallinity should be related to the structural dynamics of starch. In this study, we used quasi-elastic neutron scattering (QENS) to investigate changes in the molecular dynamics of cooked rice starch during retrogradation. The width of the measured QENS narrowed with retrogradation. The elastic incoherent structure factor (EISF) increased, which indicated that the molecular dynamics are spatially suppressed upon retrogradation. Analysis of EISF with a bimodal continuous diffusion model, where low and high mobilities are assumed to correspond to crystalline and amorphous phases, respectively, showed that the fraction of the low-mobility component increases with retrogradation.

Journal Articles

Polarized neutrons observed nanometer-thick crystalline ice plates in frozen glucose solution

Kumada, Takayuki; Nakagawa, Hiroshi; Miura, Daisuke; Sekine, Yurina; Motokawa, Ryuhei; Hiroi, Kosuke; Inamura, Yasuhiro; Oku, Takayuki; Oishi, Kazuki*; Morikawa, Toshiaki*; et al.

Journal of Physical Chemistry Letters (Internet), 14(34), p.7638 - 7643, 2023/08

The structure of nano-ice crystals in rapidly frozen glucose solution was elucidated by using spin-contrast-variation small-angle neutron scattering, which distinguishes the nano-ice crystal signal from the frozen amorphous solution signal by the polarization-dependent neutron scattering. The analysis revealed that the nano-ice crystals form a planar structure with a diameter exceeding tens of nanometers and a thickness of 1 nm, which is close to the critical nucleation size. This result suggests that the glucose molecules are preferentially bound to a specific face of nano-ice crystals, and then block the crystal growth perpendicular to that face.

JAEA Reports

Proceedings of the 34th Meeting for Tandem Accelerators and their Associated Technologies

Kabumoto, Hiroshi; Nakagawa, Sohei; Matsuda, Makoto

JAEA-Conf 2022-002, 146 Pages, 2023/03

JAEA-Conf-2022-002.pdf:9.89MB

"The 34th Meeting for Tandem Accelerators and their Associated Technologies" was held on July 21-22, 2022 organized by Nuclear Science Research Institute of the Japan Atomic Energy Agency. This meeting was held only on-line for preventing the spread of COVID-19 infection. The purpose of this meeting is contribution of development for related technology and of management of facilities through exchange of information among the researchers and engineers using and operating electrostatics accelerator facilities like tandem accelerators. There were 25 presentations which contains current status report of facility, technical development of accelerator, research of application. The total number of participants was a hundred, from 26 universities, research organizations and industries. This meeting consisted of only oral session, a poster session was not carried out because of on-line meeting. This proceeding compiles the contents of report papers in the meeting.

Journal Articles

Incoherent neutron scattering and Terahertz time-domain spectroscopy on protein and hydration water

Nakagawa, Hiroshi; Yamamoto, Naoki*

Life (Internet), 13(2), p.318_1 - 318_15, 2023/02

 Times Cited Count:0 Percentile:49(Biology)

Incoherent neutron scattering and terahertz spectroscopy have approximately the same energy range of measurement. Since both techniques are used to study the dynamics of proteins and hydrated water, it is important to review the advantages and disadvantages of both techniques and the relevant literature. To the best of our knowledge, there is no review of both methods, and we believe that this review is of high value.

Journal Articles

Present status of JAEA-Tokai tandem accelerator

Kabumoto, Hiroshi; Matsuda, Makoto; Nakamura, Masahiko; Ishizaki, Nobuhiro; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Nakagawa, Sohei; Abe, Shinichi

Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1109 - 1113, 2023/01

no abstracts in English

Journal Articles

Effect of water activity on the mechanical glass transition and dynamical transition of bacteria

Sogabe, Tomochika*; Nakagawa, Hiroshi; Yamada, Takeshi*; Koseki, Shigenobu*; Kawai, Kiyoshi*

Biophysical Journal, 121(20), p.3874 - 3882, 2022/10

 Times Cited Count:1 Percentile:21.24(Biophysics)

The purpose of this study was to clarify the glass transition behavior of bacteria ($$Cronobacter sakazakii$$) as a function of water activity ($$a_{rm w}$$). Mechanical relaxation was investigated at 298 K, and the mechanical $$a_{rm wc}$$ ($$a_{rm w}$$ at which mechanical glass transition occurs at 298 K) was determined to be 0.667. Temperature-dependency of mean square displacement was investigated by inelastic neutron scattering. From the linear fitting, two dynamical transition temperatures (low and high-$$T_{rm ds}$$) were determined. There was a minor effect of $$a_{rm w}$$ on the low-$$T_{rm ds}$$ except for the anhydrous sample. The high-$$T_{rm ds}$$ largely increased with the decrease in $$a_{rm w}$$. The dynamical $$a_{rm wc}$$determined by high-$$T_{rm ds}$$ (0.688) was slightly higher than the mechanical $$a_{rm wc}$$ because of the difference in the measurement time-scale. The high-$$T_{rm ds}$$ was converted to the glass transition temperature ($$T_{rm g}$$), and anhydrous $$T_{rm g}$$ was estimated to be 411 K. Bacterial inactive-active transition was discussed according to the glass transition behavior.

Journal Articles

Data collection for dilute protein solutions via a neutron backscattering spectrometer

Tominaga, Taiki*; Nakagawa, Hiroshi; Sahara, Masae*; Oda, Takashi*; Inoue, Rintaro*; Sugiyama, Masaaki*

Life (Internet), 12(5), p.675_1 - 675_9, 2022/05

 Times Cited Count:0 Percentile:0.01(Biology)

The background scattering of sample cells suitable for aqueous protein solution samples, conducted with a neutron backscattering spectrometer, was evaluated. It was found that the scattering intensity of an aluminum sample cell coated with boehmite using D$$_{2}$$O was lower than that of a sample cell coated with regular water (H$$_{2}$$O). In addition, meticulous attention to cells with small individual weight differences and the positional reproducibility of the sample cell relative to the spectrometer neutron beam position enabled the accurate subtraction of the scattering profiles of the D$$_{2}$$O buffer and the sample container. Consequently, high quality information on protein dynamics could be extracted from dilute protein solutions.

Journal Articles

Small-angle scattering and neutron spin echo on biomolecules

Nakagawa, Hiroshi; Matsuo, Tatsuhito*

Hamon, 32(1), p.12 - 15, 2022/02

To elucidate, predict, and control the biological functions of proteins, it is important to clarify their solution structure and dynamics. Small-angle scattering is one of effective methods for examining the changes in their structures and dynamics due to their binding with target molecules under physiological conditions, although its resolution is lower than that of crystallography, which provides structural information at atomic resolution. In addition, neutron spin echo is the only technique that can measure the conformational dynamics of proteins in the Q-region, which is covered by small-angle scattering. In this paper, we will introduce some of our recent studies using small-angle scattering and neutron spin echo.

Journal Articles

Dynamics of biomacromolecules observed by incoherent neutron scattering

Matsuo, Tatsuhito*; Nakagawa, Hiroshi

Hamon, 32(1), p.8 - 11, 2022/02

Incoherent neutron scattering is a powerful tool to investigate the dynamics of biomolecules and water. In this article, a new dynamical model called Matryoshka model is first described, which provides detailed information on the motions contained in the phospholipid molecules based on the scattering spectra. In the latter half of the article, a relationship between water activity and water mobility, and the effects of pressure and hydration on protein dynamics are discussed. These studies demonstrate the advancement of analytical methods which provide ever more detailed information for elucidating the mechanism of biological functions.

Journal Articles

Nanosecond structural dynamics of intrinsically disordered $$beta$$-casein micelles using neutron spectroscopy

Nakagawa, Hiroshi; Appavou, M.-S.*; Wuttke, J.*; Zamponi, M.*; Holderer, O.*; Schrader, T.*; Richter, D.*; Doster, W.*

Joint Annual Report 2021 of the MLZ and FRM II, P. 55, 2022/00

 Times Cited Count:0 Percentile:0.01(Biophysics)

$$beta$$-casein undergoes a reversible endothermic self-association with increasing temperature, forming micelles of limited size. We characterize the structural flexibility in terms of nano-second molecular motions. We report on two relaxation processes on a nano-second and a sub-nano-second time scale for $$beta$$-casein in solution. Both processes are analyzed by Brownian Oscillator model, by which the spring constant can be defined in the isotropic parabolic potential. The slower process seems a characteristic feature of the unfolded structure, and dividing the relaxation time by the solvent viscosity removes most of the temperature dependence, indicating that indicates, the process involves density fluctuations of the solvent. The faster process has a smaller amplitude and requires hydration water. The flexibility of a $$beta$$-casein monomer is preserved in the micelle.

Journal Articles

Analysis of nanostructures and hydration states of foods by neutron scattering and diffraction

Nakagawa, Hiroshi

Aguribaio, 6(1), p.44 - 46, 2021/12

In order to understand the macroscopic physical properties that characterize the quality of food, such as shelf life and texture, it is important to understand the relationship between microscopic information on the nanostructure and hydration state of food molecules and macroscopic observables. The elucidation of the complex hierarchical structure of food molecules from nano to micro scale and the interaction and hydration state within the molecular structure is one of the central themes in food physics. Small-angle neutron scattering and quasi-elastic scattering methods can be used to analyze molecular structures and molecular motions on such spatial scales.

Journal Articles

Nanosecond structural dynamics of intrinsically disordered $$beta$$-casein micelles by neutron spectroscopy

Nakagawa, Hiroshi; Appavou, M.-S.*; Wuttke, J.*; Zamponi, M.*; Holderer, O.*; Schrader, T. E.*; Richter, D.*; Doster, W.*

Biophysical Journal, 120(23), p.5408 - 5420, 2021/12

 Times Cited Count:0 Percentile:8.52(Biophysics)

Casein proteins are characterized by its extended structural features and its dynamics, which are different from those of typical folded proteins, due to a large number of proline residues. We were able to describe the unique structural dynamics by Orenstein-Uhlenbeck Brownian oscillator model by several types of QENS experiments with wide time-scales. The characterized dynamics also allowed us to discuss the effective sequestration of calcium phosphate in terms of its unique dynamical structure. The biological role of the physical processes of the proteins on the nanosecond order on the biological functions is presented.

Journal Articles

Protein hydration and its freezing phenomena; Toward the application for cell freezing and frozen food storage

Yamamoto, Naoki*; Nakanishi, Masahiro*; Rajan, R.*; Nakagawa, Hiroshi

Biophysics and Physicobiology (Internet), 18, p.284 - 288, 2021/12

Water is an indispensable solvent for living things. $$sim$$60% of our body is composed of water, the lack of which causes lots of fatal problems. It has also been known that protein function is performed only when it accompanies water molecules around the surface, i.e. hydration water molecules. Therefore, it is essential to understand how water and biological component interact with each other in the view point of structure and dynamics. Freezing is a fundamental and simple phenomenon of water, and thus can be used as a probe for the purpose. Furthermore, preservation of cells and proteins under low temperature is crucial for numerous applications, which in turn triggers a myriad of undesirable consequences because of the freezing.

Journal Articles

Evaluation of sample cell materials for aqueous solutions used in quasi-elastic neutron scattering measurements

Tominaga, Taiki*; Sahara, Masae*; Kawakita, Yukinobu; Nakagawa, Hiroshi; Yamada, Takeshi*

Journal of Applied Crystallography, 54(6), p.1631 - 1640, 2021/12

 Times Cited Count:3 Percentile:46.68(Chemistry, Multidisciplinary)

Journal Articles

Hydration and its hydrogen bonding state on a protein surface in the crystalline state as revealed by molecular dynamics simulation

Nakagawa, Hiroshi; Tamada, Taro*

Frontiers in Chemistry (Internet), 9, p.738077_1 - 738077_7, 2021/10

 Times Cited Count:5 Percentile:46.16(Chemistry, Multidisciplinary)

Protein hydration is crucial for the stability and molecular recognition of a protein. Water molecules interact with a protein surface via hydrogen bonding. Here, we examined the hydration structure and hydrogen bonding state of a globular protein, staphylococcal nuclease, at various hydration levels in a crystalline state by all-atom molecular dynamics simulation. The hydrophobic residue surface was found to be more hydrated than the hydrophilic residue surface, but both were uniformly hydrated in response to increased water content. In addition, the hydrogen bonds in hydrated water have a tetrahedral structure, which is not much different from the structure of bulk water. The hydrogen bonding structure is compatible with the results of neutron crystallography. The simulations are useful for analyzing the hydration structure and hydrogen bonding state in the crystalline state, and will greatly assist in the further analysis of the information obtained from crystal structure analysis.

Journal Articles

Molecular dynamics of water and water activity in glycerol-water mixtures

Nakagawa, Hiroshi

Teion Seibutsu Kogakkai-Shi, 67(2), p.129 - 133, 2021/10

Water activity is an indication of the microbial growth, enzymatic activity, preservation, and quality of foods. The water activity of glycerol-water mixtures can be controlled by changing its ratio. In this study, the diffusive dynamics of water were investigated at various water activities by incoherent quasi-elastic neutron scattering. It was found that water activity dependent diffusive water dynamics is correlated with the water sorption isotherm.

278 (Records 1-20 displayed on this page)