EHPRG: The European High Pressure Research Group

## Welcome

Welcome to the official website of the European High Pressure Research Group (EHPRG).

EHPRG is non-profitable academic association established in 1963 which is devoted to science and technology of matter under high pressure. It organizes an annual meeting which brings together hundreds of scientists of various fields, mainly physics, chemistry, Earth and planetary sciences, bio- and food science and technology.

The reasonable size of the group, low conference fees, and a friendly relationship between the attendants have made EHPRG meetings a major event in the European high-pressure community for more than half a century.

## Upcoming EHPRG Meeting

The 57th European High Pressure Research Group Meeting on High Pressure Science and Technology (EHPRG-2019) will be held in Prague, Czech Republic, from 1st to 6th September 2019. The 57th EHPRG Meeting will be chaired by Jiří Prchal (Charles University, Prague, Czech Republic).
For more information, please visit the official webpage of the 57th EHPRG Meeting.

## High-pressure in the headlines

Selection of high-pressure related titles from top scientific journals.

Pressure’s 400-year-old measurement techniques get an upgrade
by Elizabeth Gibney

Nature, Published online: 20 June 2019; doi:10.1038/d41586-019-01950-9

Lasers and quantum calculations help metrologists to update centuries-old mercury methods.
20 Jun 2019 at 12:00am
Plantations take economic pressure off natural forests
by Jaboury Ghazoul

Nature, Published online: 18 June 2019; doi:10.1038/d41586-019-01878-0

Plantations take economic pressure off natural forests
18 Jun 2019 at 12:00am
The stability-limit conjecture revisited
by Pheerawich Chitnelawong
The Journal of Chemical Physics, Volume 150, Issue 23, June 2019.
The stability-limit conjecture (SLC) proposes that the liquid spinodal of water returns to positive pressure in the supercooled region and that the apparent divergence of water’s thermodynamic response functions as temperature decreases are explained by the approach to this re-entrant spinodal. Subsequently, it has been argued that the predictions of the SLC are inconsistent with general thermodynamic principles. Here, we reconsider the thermodynamic viability of the SLC by examining a model equation of state for water which was first studied to clarify the relationship of the SLC to the proposed liquid-liquid phase transition in supercooled water. By demonstrating that a binodal may terminate on a spinodal at a point that is not a critical point, we show that the SLC is thermodynamically permissible in a system that has both a liquid-gas and a liquid-liquid phase transition. We also describe and clarify other unusual thermodynamic behavior that may arise in such a system, particularly that associated with the so-called “critical-point-free” scenario for a liquid-liquid phase transition, which may apply to the case of liquid Si.
17 Jun 2019 at 7:26am
Is water one liquid or two?
by A. K. Soper
The Journal of Chemical Physics, Volume 150, Issue 23, June 2019.
The idea that water is a mixture of two distinct states is analyzed in some detail. It is shown that the known compressibility of water is in fact sufficiently small that for a volume of water of size 1 nm3, the density fluctuations are of order 4% of the average density. This is much smaller than the ≈25% density fluctuations that would be required for significant regions of high and low density water to occur on this volume scale. It is also pointed out that the density fluctuations in water are, if anything, smaller than those that occur in other common liquids which do not have the anomalous properties of water. It is shown that if the distribution of density fluctuations is unimodal, the system is in the one-phase region, and if bimodal, it is in the two-phase region. None of the liquid or amorphous phases of water explored in this work give any sign of being in the two-phase region. Existing neutron and X-ray scattering data on water in the amorphous phases, and in the stable liquid phases as a function pressure and temperature, are subject to a new set of empirical potential structure refinement simulations. These simulations are interrogated for their configurational entropy, using a spherical harmonic reconstruction of the full orientational pair correlation function. It is shown that the excess pair entropy derived from this function, plus the known perfect gas contributions, give a reasonable account of the total entropy of water, within the likely errors. This estimated entropy follows the expected declining trend with decreasing temperature. Evidence that higher density water will have higher entropy than lower density water emerges, in accordance with what is expected from the negative thermal expansion coefficient of water at low temperatures. However, this entropy increase is not large and goes through a maximum before declining at yet higher densities and pressures, in a manner reminiscent of what has been previously observed in the diffusion coefficient as a function of pressure. There is no evidence that ambient water can be regarded as patches of high density, high entropy and low density, low entropy liquid, as some have claimed, since high density water has a similar entropy to low density water. There is some evidence that the distinction between these two states will become more pronounced as the temperature is lowered. Extensive discussion of the use of order parameters to describe water structure is given, and it is pointed out that these indices generally cannot be used to infer two-state behavior.
18 Jun 2019 at 7:31am
Importance of zero-point energy for crystalline ice phases: A comparison of force fields and density functional theory
by Soroush Rasti
The Journal of Chemical Physics, Volume 150, Issue 23, June 2019.
Density functional theory (DFT) including van der Waals (vdW) interactions and accounting for zero-point energy (ZPE) is believed to provide a good description of crystalline ice phases [B. Pamuk et al., Phys. Rev. Lett. 108, 193003 (2012)]. Given the computational cost of DFT, it is not surprising that extensive phonon calculations, which yield the ZPE, have only been done for a limited amount of ice structures. Computationally convenient force fields on the other hand are the method of choice for large systems and/or dynamical simulations, e.g., of supercooled water. Here, we present a systematic comparison for seven hydrogen-ordered crystalline ice phases (Ih, IX, II, XIII, XIV, XV, and VIII) between many commonly used nonpolarizable force fields and density functionals, including some recently developed meta-GGA functionals and accounting for vdW interactions. Starting from the experimentally determined crystal structures, we perform space-group-constrained structural relaxations. These provide the starting point for highly accurate phonon calculations that yield effectively volume-dependent ZPEs within the quasiharmonic approximation. In particular, when including ZPE, the force fields show a remarkably good performance for equilibrium volumes and cohesive energies superior to many density functionals. A decomposition of the cohesive energies into intramolecular deformation, electrostatic, and vdW contributions quantifies the differences between force fields and DFT. Results for the equilibrium volumes and phase transition pressures for all studied force fields are much more strongly affected by ZPE than all studied density functionals. We track this down to significantly smaller shifts of the O–H-stretch modes and compare with experimental data from Raman spectroscopy.
19 Jun 2019 at 8:02am
Surface tension of supercooled water nanodroplets from computer simulations
by Shahrazad M. A. Malek
The Journal of Chemical Physics, Volume 150, Issue 23, June 2019.
We estimate the liquid-vapor surface tension from simulations of TIP4P/2005 water nanodroplets of size N = 100 to 2880 molecules over a temperature T range of 180 K–300 K. We compute the planar surface tension γp, the curvature-dependent surface tension γs, and the Tolman length δ, via two approaches, one based on the pressure tensor (the “mechanical route”) and the other on the Laplace pressure (the “thermodynamic route”). We find that these two routes give different results for γp, γs, and δ although in all cases, we find that δ ≥ 0 and is independent of T. Nonetheless, the T dependence of γp is consistent between the two routes and with that of Vega and de Miguel [J. Chem. Phys. 126, 154707 (2007)] down to the crossing of the Widom line at 230 K for ambient pressure. Below 230 K, γp rises more rapidly on cooling than predicted from behavior for T ≥ 300 K. We show that the increase in γp at low T is correlated with the emergence of a well-structured random tetrahedral network in our nanodroplet cores and thus that the surface tension can be used as a probe to detect behavior associated with the proposed liquid-liquid phase transition in supercooled water.
21 Jun 2019 at 6:41am
Persistent Octahedral Coordination in Amorphous ${\mathrm{GeO}}_{2}$ Up to 100 GPa by $\mathrm{K}{β}^{′′}$ X-Ray Emission Spectroscopy
by G. Spiekermann, M. Harder, K. Gilmore, P. Zalden, Ch. J. Sahle, S. Petitgirard, M. Wilke, N. Biedermann, C. Weis, W. Morgenroth, J. S. Tse, E. Kulik, N. Nishiyama, H. Yavaş, and C. Sternemann
Author(s): G. Spiekermann, M. Harder, K. Gilmore, P. Zalden, Ch. J. Sahle, S. Petitgirard, M. Wilke, N. Biedermann, C. Weis, W. Morgenroth, J. S. Tse, E. Kulik, N. Nishiyama, H. Yavaş, and C. Sternemann

X-ray emission spectra reveal that under pressure conditions of Earth’s lower mantle, the compaction mechanism in amorphous germanium dioxide on the atomic scale is similar to that of its crystalline form.

[Phys. Rev. X 9, 011025] Published Wed Feb 06, 2019
6 Feb 2019 at 11:00am
Solids, liquids, and gases under high pressure
by Ho-Kwang Mao, Xiao-Jia Chen, Yang Ding, Bing Li, and Lin Wang
Author(s): Ho-Kwang Mao, Xiao-Jia Chen, Yang Ding, Bing Li, and Lin Wang

The effect of adding high pressure as a control parameter in solids, liquids, and gases expands opportunities to observe unexpected novel phenomena and understand matter in extreme environments. This review on high pressure science highlights subjects ranging from quantum criticality to Earth science. State-of-the-art experimental methods at megabar pressures are also discussed. The proliferation of pressure-induced phases illustrate promising new directions for this field of research.

[Rev. Mod. Phys. 90, 015007] Published Tue Mar 20, 2018
20 Mar 2018 at 11:00am
Colloquium: High pressure and road to room temperature superconductivity
by Lev P. Gor’kov and Vladimir Z. Kresin
Author(s): Lev P. Gor’kov and Vladimir Z. Kresin

Even after three decades of development, high-temperature superconductivity remains one of the most challenging theoretical and experimental areas in condensed matter physics. In this Colloquium some new discoveries in this area are reviewed and possible routes toward much higher transition temperatures are analyzed.

[Rev. Mod. Phys. 90, 011001] Published Tue Jan 09, 2018
9 Jan 2018 at 11:00am
Equations of state for supernovae and compact stars
by M. Oertel, M. Hempel, T. Klähn, and S. Typel
Author(s): M. Oertel, M. Hempel, T. Klähn, and S. Typel

What are the thermodynamic properties of matter at extreme densities, even exceeding nuclear matter density severely? How can we describe the composition of matter for such conditions, the resulting pressure, and the maximum mass of cold neutron stars? How is this affected by finite temperatures, as they occur in core collapse supernovae and in compact star mergers? This review addresses these points within the framework of constraints from experiments as well as astronomical observations.

[Rev. Mod. Phys. 89, 015007] Published Wed Mar 15, 2017
15 Mar 2017 at 11:00am
High-pressure synthesis of the $\mathrm{BiV}{\mathrm{O}}_{3}$ perovskite
by R. A. Klein, A. B. Altman, R. J. Saballos, J. P. S. Walsh, A. D. Tamerius, Y. Meng, D. Puggioni, S. D. Jacobsen, J. M. Rondinelli, and D. E. Freedman
Author(s): R. A. Klein, A. B. Altman, R. J. Saballos, J. P. S. Walsh, A. D. Tamerius, Y. Meng, D. Puggioni, S. D. Jacobsen, J. M. Rondinelli, and D. E. Freedman

We report the high-pressure, high-temperature synthesis of $\mathrm{BiV}{\mathrm{O}}_{3}$, a cubic perovskite that thus far has remained inaccessible under ambient pressure conditions. We created this material at $∼25$ GPa and 1500 K in a laser-heated diamond-anvil cell and recovered it to ambient p...

[Phys. Rev. Materials 3, 064411] Published Thu Jun 20, 2019
20 Jun 2019 at 12:00pm
Ambient conditions disordered-ordered phase transition of two-dimensional interfacial water molecules dependent on charge dipole moment
by Chunlei Wang, Chonghai Qi, Yusong Tu, Xuechuan Nie, and Shanshan Liang
Author(s): Chunlei Wang, Chonghai Qi, Yusong Tu, Xuechuan Nie, and Shanshan Liang

Phase transitions of water molecules are commonly expected to occur only under extreme conditions, such as nanoconfinement, high pressure, or low temperature. We herein report the disordered-ordered phase transition of two-dimensional interfacial water molecules under ambient conditions using molecu...

[Phys. Rev. Materials 3, 065602] Published Mon Jun 03, 2019
3 Jun 2019 at 12:00pm
XMCD study of magnetism and valence state in iron-substituted strontium titanate
by Astera S. Tang, Jonathan Pelliciari, Qi Song, Qian Song, Shuai Ning, John W. Freeland, Riccardo Comin, and Caroline A. Ross
Author(s): Astera S. Tang, Jonathan Pelliciari, Qi Song, Qian Song, Shuai Ning, John W. Freeland, Riccardo Comin, and Caroline A. Ross

Room-temperature ferromagnetism was characterized for thin films of $\mathrm{SrT}{\mathrm{i}}_{0.6}\mathrm{F}{\mathrm{e}}_{0.4}{\mathrm{O}}_{3\text{−}δ}$ grown by pulsed laser deposition on $\mathrm{SrTi}{\mathrm{O}}_{3}$ and Si substrates under different oxygen pressures and after annealing under o...

[Phys. Rev. Materials 3, 054408] Published Fri May 17, 2019
17 May 2019 at 12:00pm
Elastic anisotropy and single-crystal moduli of solid argon up to 64 GPa from time-domain Brillouin scattering
by Samuel Raetz, Maju Kuriakose, Philippe Djemia, Sergey M. Nikitin, Nikolay Chigarev, Vincent Tournat, Alain Bulou, Alexey Lomonosov, Vitalyi E. Gusev, and Andreas Zerr
Author(s): Samuel Raetz, Maju Kuriakose, Philippe Djemia, Sergey M. Nikitin, Nikolay Chigarev, Vincent Tournat, Alain Bulou, Alexey Lomonosov, Vitalyi E. Gusev, and Andreas Zerr

Single-crystal elastic moduli ${C}_{ij}$, shear modulus $G$, and Zener anisotropic ratio $A$ of solid argon having the face-centered cubic (fcc) structure were determined at high pressures between 12 and 64 GPa using a combination of experimental and theoretical approaches. The experimental data, na...

[Phys. Rev. B 99, 224102] Published Thu Jun 20, 2019
20 Jun 2019 at 12:00pm
Disorder unveils Mott quantum criticality behind a first-order transition in the quasi-two-dimensional organic conductor $κ\text{−}(\text{ET}){}_{2}\text{Cu}[\text{N}(\text{CN}{)}_{2}]\text{Cl}$
by Mizuki Urai, Tetsuya Furukawa, Yasuhide Seki, Kazuya Miyagawa, Takahiko Sasaki, Hiromi Taniguchi, and Kazushi Kanoda
Author(s): Mizuki Urai, Tetsuya Furukawa, Yasuhide Seki, Kazuya Miyagawa, Takahiko Sasaki, Hiromi Taniguchi, and Kazushi Kanoda

We show the significant impact of weak disorder on the Mott transition by investigating electronic transport in a systematically x-ray-irradiated layered organic conductor under continuous pressure control. The critical end point of the first-order Mott transition is dramatically suppressed by such ...

[Phys. Rev. B 99, 245139] Published Thu Jun 20, 2019
20 Jun 2019 at 12:00pm
Polar state induced by block-type lattice distortions in ${\mathrm{BaFe}}_{2}{\mathrm{Se}}_{3}$ with quasi-one-dimensional ladder structure
by Takuya Aoyama, Satoshi Imaizumi, Takuya Togashi, Yoshifumi Sato, Kazuki Hashizume, Yusuke Nambu, Yasuyuki Hirata, Masakazu Matsubara, and Kenya Ohgushi
Author(s): Takuya Aoyama, Satoshi Imaizumi, Takuya Togashi, Yoshifumi Sato, Kazuki Hashizume, Yusuke Nambu, Yasuyuki Hirata, Masakazu Matsubara, and Kenya Ohgushi

A stripe-type magnetic structure and related orbital ordering are universally observed in iron-based superconductors. As an exception, the quasi-one-dimensional ladder material ${\mathrm{BaFe}}_{2}{\mathrm{Se}}_{3}$, which shows pressure-induced superconductivity, exhibits a block-type antiferromagn...

[Phys. Rev. B 99, 241109(R)] Published Wed Jun 19, 2019
19 Jun 2019 at 12:00pm
Infrared spectroscopy study of the nodal-line semimetal candidate ZrSiTe under pressure: Hints for pressure-induced phase transitions
by J. Ebad-Allah, M. Krottenmüller, J. Hu, Y. L. Zhu, Z. Q. Mao, and C. A. Kuntscher
Author(s): J. Ebad-Allah, M. Krottenmüller, J. Hu, Y. L. Zhu, Z. Q. Mao, and C. A. Kuntscher

We studied the effect of external pressure on the optical response of the nodal-line semimetal candidate ZrSiTe by reflectivity measurements. At pressures of a few GPa, the reflectivity, optical conductivity, and loss function are strongly affected in the whole measured frequency range ($200–16\phan... [Phys. Rev. B 99, 245133] Published Wed Jun 19, 2019 19 Jun 2019 at 12:00pm Inverse pressure-induced Mott transition in${\mathrm{TiPO}}_{4}$by H. Johan M. Jönsson, Marcus Ekholm, Maxim Bykov, Leonid Dubrovinsky, Sander van Smaalen, and Igor A. Abrikosov Author(s): H. Johan M. Jönsson, Marcus Ekholm, Maxim Bykov, Leonid Dubrovinsky, Sander van Smaalen, and Igor A. Abrikosov${\mathrm{TiPO}}_{4}$shows interesting structural and magnetic properties as temperature and pressure are varied, such as a spin-Peierls phase transition and the development of incommensurate modulations of the lattice. Recently, high-pressure experiments for${\mathrm{TiPO}}_{4}$reported two stru... [Phys. Rev. B 99, 245132] Published Tue Jun 18, 2019 18 Jun 2019 at 12:00pm Chemical composition induced quantum phase transition in${\mathrm{Cs}}_{1−x}{\mathrm{Rb}}_{x}{\mathrm{FeCl}}_{3}\$
by S. Hayashida, L. Stoppel, Z. Yan, S. Gvasaliya, A. Podlesnyak, and A. Zheludev
Author(s): S. Hayashida, L. Stoppel, Z. Yan, S. Gvasaliya, A. Podlesnyak, and A. Zheludev

Much of what we know about quantum criticality comes from studies of quantum phase transitions between paramagnetic and magnetically ordered phases. These are usually driven by magnetic field or pressure. Here, the authors report that in CsFeCl3, one of the precious few materials exhibiting pressure-induced magnetic order, a similar transition can also be induced by chemical substitution. Cs1−xRbxFeCl3 continuously evolves from a gapped quantum paramagnet to a critical gapless state and finally to magnetic long-range order. No bulky pressure cells are required, which makes all thermodynamic and spectroscopic properties easily accessible to measurement.

[Phys. Rev. B 99, 224420] Published Mon Jun 17, 2019
17 Jun 2019 at 12:00pm
10th International Conference on High Pressure Bioscience and Biotechnology (HPBB2018)
by Fumiyoshi Abe
Volume 39, Issue 2, June 2019, Page 191-192
.

22 May 2019 at 4:17am
High pressure studies on the misfolding and aggregation of p53 in cancer and of α-synuclein in Parkinson’s disease
by Guilherme A. P. de Oliveira
Volume 39, Issue 2, June 2019, Page 193-201
.

11 Feb 2019 at 6:04am
Pressure-induced structural changes of alanine oligopeptides in aqueous solutions
by Takahiro Takekiyo
Volume 39, Issue 2, June 2019, Page 202-209
.

1 Mar 2019 at 6:42am
Molecular chaperone-like properties of sodium caseinate to suppress the pressure-induced aggregation of β-lactoglobulin
by Jin-Song He
Volume 39, Issue 2, June 2019, Page 210-217
.

11 Feb 2019 at 6:02am
Quantitative analysis of dissociation of LDH by high pressure native PAGE
by Tomoya Miwa
Volume 39, Issue 2, June 2019, Page 218-224
.

11 Jan 2019 at 8:11am
Adaptations for pressure and temperature effects on loop motion in Escherichia coli and Moritella profunda dihydrofolate reductase
by Qi Huang
Volume 39, Issue 2, June 2019, Page 225-237
.

5 Mar 2019 at 9:48am
Salt effect on bilayer phase transitions of dipalmitoylphosphatidylglycerol in saline water under high pressure
by Masaki Goto
Volume 39, Issue 2, June 2019, Page 238-247
.

4 Apr 2019 at 11:11am
Poly 3-hydroxybutyrate-co-3-hydroxyhexanoate films can be degraded by the deep-sea microbes at high pressure and low temperature conditions
by Chiaki Kato
Volume 39, Issue 2, June 2019, Page 248-257
.

1 Mar 2019 at 5:24am
Identification of a regulatory element for yeast tryptophan permease Tat2 ubiquitination using high hydrostatic pressure
by Ryoga Ishii
Volume 39, Issue 2, June 2019, Page 258-266
.

1 Feb 2019 at 6:21am
Critical events leading to cellular mortality of yeast cells following hydrostatic pressure treatment
Volume 39, Issue 2, June 2019, Page 267-272
.

9 Dec 2018 at 12:44pm
Critical damage to the cellular organelles of Saccharomyces cerevisiae under sublethal conditions upon high pressure carbon dioxide treatment
by Ukyo Takahashi
Volume 39, Issue 2, June 2019, Page 273-279
.

2 May 2019 at 6:40am
High-throughput screening of food additives with synergistic effects on high hydrostatic pressure inactivation of budding yeast
by Akinori Iguchi
Volume 39, Issue 2, June 2019, Page 280-292
.

30 Mar 2019 at 10:22am
Pressure tolerance of Artemia cysts compressed in water medium
by Rachael Hazael
Volume 39, Issue 2, June 2019, Page 293-300
.

4 Feb 2019 at 10:41am
High hydrostatic pressure pasteurization of a draft sake brewed using a Niigata-sake yeast
by Kazuki Nomura
Volume 39, Issue 2, June 2019, Page 301-312
.

30 Mar 2019 at 10:24am
Effect of high hydrostatic pressure on enzyme activity in unpasteurized draft sake
by Toru Shigematsu
Volume 39, Issue 2, June 2019, Page 313-323
.

25 Apr 2019 at 3:58am
Listeria monocytogenes cells injured by high hydrostatic pressure and their recovery in nutrient-rich or -free medium during cold storage
by Yoshiko Nakaura
Volume 39, Issue 2, June 2019, Page 324-333
.

1 Mar 2019 at 3:10am
Effect of plating and incubation conditions on the detection of lactic acid bacteria after high hydrostatic pressure treatment
by Masato Nakane
Volume 39, Issue 2, June 2019, Page 334-343
.

7 Feb 2019 at 5:17am
Evaluation of the effect of high pressure carbon dioxide-pasteurized food on animal health
by Ayane Hibi
Volume 39, Issue 2, June 2019, Page 357-366
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11 Feb 2019 at 6:08am
Conversion of waste meat to resources by enzymatic reaction under high pressure carbon dioxide conditions
by Tonghuan Yu
Volume 39, Issue 2, June 2019, Page 367-373
.

19 Mar 2019 at 7:25am
Whey proteins-epicatechin interactions in a model specialized food product treated by high pressure
by Valentin Clion
Volume 39, Issue 2, June 2019, Page 374-384
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2 May 2019 at 4:23am
Effect of high hydrostatic pressure and reducing sodium chloride and phosphate on physicochemical properties of beef gels
by Anastasiia Maksimenko
Volume 39, Issue 2, June 2019, Page 385-397
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4 Mar 2019 at 2:39am
Enrichment of free amino acid content and reduction of astringent taste compounds in soybean by high hydrostatic pressure
by Shigeaki Ueno
Volume 39, Issue 2, June 2019, Page 398-407
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6 Apr 2019 at 12:02pm
The effect of high hydrostatic pressure on taste substance distribution in fresh green tea leaves
by Hsiuming Liu
Volume 39, Issue 2, June 2019, Page 408-416
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25 Apr 2019 at 2:56pm
Modified Bridgman anvils for high pressure synthesis and neutron scattering
by Bianca Haberl
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17 Jun 2019 at 8:18am
Development of a technique for high pressure neutron diffraction at 40 GPa with a Paris-Edinburgh press
by T. Hattori
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4 Jun 2019 at 6:21am
Effects of high hydrostatic pressure on β-glucan content, swelling power, starch damage, and pasting properties of high-β-glucan barley flour
by Shigeaki Ueno
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29 Mar 2019 at 1:58pm