1
|
Dixit M, Taniguchi T. Role of Terminal Groups of cis-1,4-Polyisoprene Chains in the Formation of Physical Junction Points in Natural Rubber. Biomacromolecules 2023; 24:3589-3602. [PMID: 37527033 DOI: 10.1021/acs.biomac.3c00355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
The terminal structures of cis-1,4-polyisoprene (PI) chains play a vital role in the excellent comprehensive performance of Hevea natural rubber (NR) with properties such as high toughness, tear-resistance, and wet skid resistance. The cis-1,4-polyisoprene chain constituting NR exhibits a distinct composition of terminal groups comprising two distinct types, namely, the ω and α terminal groups. The structures of the ω terminal [dimethyl allyl (DMA)-(trans-1,4-isoprene)2] and six kinds of α end groups of the polymer chain of NR have been explored by utilizing a newly developed 2D NMR method. In the present work, we examine different kinds of PI melt systems, and we choose various combinations of terminal groups: Hydrogen, one DMA unit with two trans isoprene units as ω end groups and ester-terminated isopentene (α1), hydroxy-terminated isopentene (α2), ester-terminated isobutane (α3), hydroxy-terminated isobutane (α4), ester-terminated 1,4-cis-isoprene (α5), and hydroxy-terminated 1,4-cis-isoprene (α6), i.e., HPIH (PI0)-pure PI (Hydrogen terminal), ωPIα1 (PII), ωPIα2 (PIII), ωPIα3 (PIIII), ωPIα4 (PIIV), ωPIα5 (PIV), and ωPIα6 (PIVI). We evaluated dynamic and static properties of PI chains such as the end-to-end vector autocorrelation function (C(t)), its average relaxation time (τ), end-to-end distance (Ree), and radius of gyration (Rg). We also estimated the diffusion coefficients of polyisoprene chains and pair correlation functions [radial distribution functions (RDFs)], potentials of mean force (PMFs) in between end residues, and survival probability (P(τ)) of end groups around the end group by analyzing the equilibrated trajectories of full-atom MD simulations. As per the examination of C(t), rotational relaxation time τ, and RDFs, we discovered that the existence of a strong hydrogen bond in α2-α2, α4-α4, and α6-α6 residues makes the dynamics of hydroxy-terminated polyisoprene chains in ωPIα2,α4,α6 melt systems slower. From the analyses of RDFs and PMFs (W(r)), the association between [α2]-[α2], [α4]-[α4], and [α6]-[α6] terminals in ωPIα2,α4,α6 melt systems is significantly stronger than in [ISO]-[ISO] [Hydrogen terminated 1,4-cis-isoprene:(ISO)] in HPIH and ω-ω, [α1]-[α1], [α3]-[α3], and [α5]-[α5] in ωPIα1,α3,α5 systems. We quantified the fraction of cluster formation of terminal groups of a given size in the seven PI melt systems by employing the criteria of PMFs. It is revealed that no stable cluster exists in the HPIH, ωPIα1, ωPIα3, and ωPIα5 melt systems. Conversely, in the ωPIα2, ωPIα4, and ωPIα6 systems, we perceived stable clusters of [(α2)p] [(α4)p] and [(α6)p] end groups where p (2 ≤ x ≤ 6). These stable clusters validate the presence of physical junction points in between hydroxy-terminated polyisoprene chains through their α2, α4, and α6 terminals. These physical junction points might be crucial for superior properties of NR such as high toughness, crack growth resistance, and strain-induced crystallization.
Collapse
Affiliation(s)
- Mayank Dixit
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Takashi Taniguchi
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| |
Collapse
|
2
|
Majidi S, Erfan-Niya H, Azamat J, Cruz-Chú ER, Walther JH. Understanding the performance of graphdiyne membrane for the separation of nitrate ions from aqueous solution at the atomistic scale. J Mol Graph Model 2023; 118:108337. [PMID: 36201877 DOI: 10.1016/j.jmgm.2022.108337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/12/2022] [Accepted: 09/15/2022] [Indexed: 10/14/2022]
Abstract
A molecular dynamics simulation study is conducted to investigate the capability of the pristine graphdiyne nanosheet for nitrate ion separation from water. The removal of nitrate ion contaminants from water is of critical importance as it represents an environmental hazard. The graphdiyne is a carbon-based membrane with pore density of 2.4 × 1018 pores/m2 and incircle radius of 2.8 Å. We show that the efficient water flow is accurately controlled through fine regulation of the exerted hydrostatic pressure. The high water permeability of 6.19 L.Day-1cm-2MPa-1 with 100% nitrate ions rejection suggests that the graphdiyne can perform as a suitable membrane for nitrate separation. The potential of mean force analysis of the single water molecule and nitrate ion indicated the free energy barriers for nitrate of about 4 times higher than that of water molecules. The results reveal the weak interaction of the water molecules and the membrane which aid to high water flux.
Collapse
Affiliation(s)
- Sima Majidi
- Faculty of Chemical and Petroleum Engineering, University of Tabriz, 51666-16471, Tabriz, Iran
| | - Hamid Erfan-Niya
- Faculty of Chemical and Petroleum Engineering, University of Tabriz, 51666-16471, Tabriz, Iran.
| | - Jafar Azamat
- Department of Basic Sciences, Farhangian University, Tehran, Iran
| | - Eduardo R Cruz-Chú
- Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, 15102, Peru
| | - Jens Honoré Walther
- Department of Mechanical Engineering, Technical University of Denmark, Nils Koppels Allé, 2800 Kgs, Lyngby, Denmark; Computational Science and Engineering Laboratory, ETH Zürich, Clausiusstrasse 33, CH-8092, Zürich, Switzerland
| |
Collapse
|
3
|
Comprehensive review on physical properties of supercritical carbon dioxide calculated by molecular simulation. KOREAN J CHEM ENG 2023. [DOI: 10.1007/s11814-022-1316-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
4
|
Majidi S, Erfan-Niya H, Azamat J, Cruz-Chú ER, Walther JH. The separation performance of porous carbon nitride membranes for removal of nitrate and nitrite ions from contaminated aqueous solutions: A molecular dynamics study. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.130208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
5
|
Dixit M, Taniguchi T. Substantial Effect of Terminal Groups in cis-Polyisoprene: A Multiscale Molecular Dynamics Simulation Study. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mayank Dixit
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Takashi Taniguchi
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| |
Collapse
|
6
|
Using Car-Parrinello simulations and microscopic order descriptors to reveal two locally favored structures with distinct molecular dipole moments and dynamics in ambient liquid water. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
|
7
|
Qiao B, Lin P, Zheng W, Wang Z, Wang D, Zhou D, Liu X. Application of supercritical CO2 extraction technology in spent nuclear fuel reprocessing. J Radioanal Nucl Chem 2021. [DOI: 10.1007/s10967-021-08069-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
8
|
Skarmoutsos I, Petsalakis ID, Samios J. The Polar Cosolvent Effect on Caffeine Solvation in Supercritical CO 2–Ethanol Mixtures: A Molecular Modeling Approach. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c00956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ioannis Skarmoutsos
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Vas. Constantinou 48, GR-116 35 Athens, Greece
| | - Ioannis D. Petsalakis
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Vas. Constantinou 48, GR-116 35 Athens, Greece
| | - Jannis Samios
- Department of Chemistry, Laboratory of Physical Chemistry, National & Kapodistrian University of Athens, Panepistimiopolis, 157-71 Athens, Greece
| |
Collapse
|
9
|
Chatwell RS, Guevara-Carrion G, Gaponenko Y, Shevtsova V, Vrabec J. Diffusion of the carbon dioxide-ethanol mixture in the extended critical region. Phys Chem Chem Phys 2021; 23:3106-3115. [PMID: 33491706 DOI: 10.1039/d0cp04985a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of traces of ethanol in supercritical carbon dioxide on the mixture's thermodynamic properties is studied by molecular simulations and Taylor dispersion measurements. This mixture is investigated along the isobar p = 10 MPa in the temperature range between T = 304 and 343 K. Along this path, the mixture undergoes two transitions: First, the Widom line is crossed, marking the transition from liquid-like to gas-like conditions. A second transition occurs from the supercritical gas-like domain to a subcritical gas. The Widom line crossover entails inflection points for most of the studied properties, i.e. density, enthalpy, shear viscosity, Maxwell-Stefan and intradiffusion coefficients. On the other hand, the transition between the super- and subcritical regions is found to be generally smooth, an observation that is qualitatively confirmed by experimental Taylor dispersion measurements. Dedicated atomistic simulations show the presence of microheterogeneities due to ethanol self-association along the investigated path, which lead to the mixture's anomalous behavior in its extended critical region.
Collapse
Affiliation(s)
- René Spencer Chatwell
- Thermodynamics and Process Engineering, Technische Universität Berlin, 10587 Berlin, Germany.
| | | | - Yuri Gaponenko
- Microgravity Research Center, Université Libre de Bruxelles, 1050 Bruxelles, Belgium
| | - Valentina Shevtsova
- Microgravity Research Center, Université Libre de Bruxelles, 1050 Bruxelles, Belgium
| | - Jadran Vrabec
- Thermodynamics and Process Engineering, Technische Universität Berlin, 10587 Berlin, Germany.
| |
Collapse
|
10
|
Karunarathna B, Jayakody RS, Karunanayake L, Govender KK. Computational development and validation of a representative MDI-BDO-based polyurethane hard segment model. J Mol Model 2021; 27:37. [PMID: 33432382 DOI: 10.1007/s00894-020-04660-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 12/16/2020] [Indexed: 10/22/2022]
Abstract
Segmented polyurethanes show extraordinary physicochemical properties, mainly owing to the nature and the chemistry of the hard segment domains. There are yet many inexplicable physiochemical properties of MDI-BDO-based hard polyurethane segments such as the geometry, cis-trans isomerism, electronic structure, chemical reactivity, the inter-hard-segment interactions, and the photo-response. In the present study, it was attempted to develop and validate a model system that would facilitate further research on the structural and chemical properties of the MDI-BDO hard segments. It was found that the trans isomer of urethane bond is more stable than the cis isomer, and it is argued here that thermal transformation from trans to cis not possible due to the high rotational energy barrier. The differences between the calculated IR spectra of the cis and trans isomers are proposed as a powerful differentiation tool. The calculated Fukui indices show that cis and trans isomers are different in their chemical reactivity. The findings of the present study suggest intermolecular and intramolecular pi-stacking and highly plausible two significant types of hydrogen bond types between hard segments. In the present study, a model system for MDI-BDO hard segment was developed and successfully validated via computational experiments. Further calculations done with the new model provided an indispensable understanding of the structure, cis-trans isomerism, reactivity, and intermolecular interactions of the MDI-BDO hard segments. The proposed model can be further improved in the future by incorporating suitable soft segments. In summary, the model system developed and validated in the present study has provided new opportunities to understand and further study the structural and chemical features of the hard segments of the MDI-BDO-based polyurethane.
Collapse
Affiliation(s)
- Baggya Karunarathna
- Centre for Scientific Computing and Advanced Drug Discovery, University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Lanka
| | - Ranga Srinath Jayakody
- Centre for Scientific Computing and Advanced Drug Discovery, University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Lanka. .,Department of Chemistry, University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Lanka.
| | - Laleen Karunanayake
- Department of Polymer Science, University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Lanka
| | - Krishna Kuben Govender
- Department of Chemical Sciences, University of Johannesburg, P.O. Box 17011, Doornfontein Campus, Johannesburg, 2028, South Africa.,Council for Scientific and Industrial Research, National Integrated Cyber Infrastructure, Centre for High Performance Computing, 15 Lower Hope Road, Rosebank, Cape Town, 7700, South Africa
| |
Collapse
|
11
|
Nair AS, Kumar S, Acharya S, Bagchi B. Rotation of small diatomics in water–ethanol mixture: Multiple breakdowns of hydrodynamic predictions. J Chem Phys 2020; 153:014504. [DOI: 10.1063/5.0005160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Anjali S. Nair
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Shubham Kumar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Subhajit Acharya
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Biman Bagchi
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| |
Collapse
|
12
|
Phan CT, Nhung NTA, Trung NT. Growth Pattern, Stability, and Properties of Complexes of C 2H 5OH and nCO 2 ( n = 1-5) Molecules: A Theoretical Study. ACS OMEGA 2020; 5:14408-14416. [PMID: 32596578 PMCID: PMC7315433 DOI: 10.1021/acsomega.0c00948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/28/2020] [Indexed: 06/11/2023]
Abstract
This work is dedicated to theoretically investigate the formation process of C2H5OH···nCO2 (n = 1-5) complexes and to shed light on the nature of interactions formed under the variation of CO2 concentration. It is found that CO2 molecules tend to locate around the polarized -OH group to interact with the lone pairs of the O atom. The interaction of ethanol with three CO2 molecules (C2H5OH···3CO2) induces the most stable structure in the sequence considered. The atoms in molecules (AIM), NCIplot, and natural bond orbital (NBO) analyses point out that the Oethanol···CCO2 tetrel bond overcomes hydrogen, chalcogen, and CO2···CO2 tetrel-bonded interactions and mainly contributes to the strength of C2H5OH···nCO2 (n = 1-5) complexes. All intermolecular interactions in the examined complexes are weakly noncovalent, and their positive cooperativity is evaluated to be slightly weaker than that of CO2 pure systems. SAPT2+ and molecular electrostatic potential (MEP) calculations indicate that the electrostatic force is the main factor underlying the attractive interplay in the complexes of C2H5OH and CO2.
Collapse
Affiliation(s)
- Cam-Tu
Dang Phan
- Laboratory
of Computational Chemistry and Modelling (LCCM), Department of Chemistry, Quy Nhon University, 170 An Duong Vuong Street, Quy Nhon City 590000, Vietnam
| | - Nguyen Thi Ai Nhung
- Department
of Chemistry, University of Sciences, Hue
University, 77 Nguyen
Hue Street, Hue City 530000, Vietnam
| | - Nguyen Tien Trung
- Laboratory
of Computational Chemistry and Modelling (LCCM), Department of Chemistry, Quy Nhon University, 170 An Duong Vuong Street, Quy Nhon City 590000, Vietnam
| |
Collapse
|
13
|
Duereh A, Sugimoto Y, Ota M, Sato Y, Inomata H. Kamlet–Taft Dipolarity/Polarizability of Binary Mixtures of Supercritical Carbon Dioxide with Cosolvents: Measurement, Prediction, and Applications in Separation Processes. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c01251] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alif Duereh
- Graduate School of Engineering, Research Center of Supercritical Fluid Technology, Tohoku University, Aramaki Aza Aoba 6-6-11, Aoba-ku, Sendai 980-8579, Japan
| | - Yuta Sugimoto
- Graduate School of Engineering, Research Center of Supercritical Fluid Technology, Tohoku University, Aramaki Aza Aoba 6-6-11, Aoba-ku, Sendai 980-8579, Japan
| | - Masaki Ota
- Graduate School of Engineering, Research Center of Supercritical Fluid Technology, Tohoku University, Aramaki Aza Aoba 6-6-11, Aoba-ku, Sendai 980-8579, Japan
- Graduate School of Environmental Studies, Tohoku University, Aramaki Aza Aoba 6-6-11, Aoba-ku, Sendai 980-8579, Japan
| | - Yoshiyuki Sato
- Faculty of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama, Kasumicho, Taihakuku, Sendai 982-8577, Japan
| | - Hiroshi Inomata
- Graduate School of Engineering, Research Center of Supercritical Fluid Technology, Tohoku University, Aramaki Aza Aoba 6-6-11, Aoba-ku, Sendai 980-8579, Japan
| |
Collapse
|
14
|
Soper AK, Skarmoutsos I, Kłos J, Samios J, Marinakis S. A study of Ar-N2 supercritical mixtures using neutron scattering, molecular dynamics simulations and quantum mechanical scattering calculations. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
15
|
Yu Y, Shi L. Vibrational solvatochromism of the ester carbonyl vibration of PCBM in organic solutions. J Chem Phys 2019. [DOI: 10.1063/1.5111046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Yue Yu
- School of Natural Sciences, University of California, Merced, California 95343, USA
| | - Liang Shi
- School of Natural Sciences, University of California, Merced, California 95343, USA
| |
Collapse
|
16
|
Liu J, Chen C, Lu C, Li W. Different mechanisms on the stabilization of POPC membrane by trehalose upon varied mechanical stress. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2018.10.094] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
17
|
Strategies for using hydrogen-bond donor/acceptor solvent pairs in developing green chemical processes with supercritical fluids. J Supercrit Fluids 2018. [DOI: 10.1016/j.supflu.2017.11.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
18
|
The Preservation of Lyophilized Human Growth Hormone Activity: how Do Buffers and Sugars Interact? Pharm Res 2018; 35:131. [DOI: 10.1007/s11095-018-2410-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 04/16/2018] [Indexed: 10/17/2022]
|
19
|
Zhang N, Chen S, Yang B, Huo J, Zhang X, Bao J, Ruan X, He G. Effect of Hydrogen-Bonding Interaction on the Arrangement and Dynamics of Water Confined in a Polyamide Membrane: A Molecular Dynamics Simulation. J Phys Chem B 2018; 122:4719-4728. [DOI: 10.1021/acs.jpcb.7b12790] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ning Zhang
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| | - Shaomin Chen
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| | - Boyun Yang
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| | - Jun Huo
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| | - Xiaopeng Zhang
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| | - Junjiang Bao
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| | - Xuehua Ruan
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| | - Gaohong He
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| |
Collapse
|
20
|
Liu J, Chen C, Li W. Protective mechanisms of α,α-trehalose revealed by molecular dynamics simulations. MOLECULAR SIMULATION 2017. [DOI: 10.1080/08927022.2017.1342126] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Jing Liu
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology, Dalian, China
| | - Cong Chen
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology, Dalian, China
| | - Weizhong Li
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology, Dalian, China
| |
Collapse
|
21
|
Feng H, Gao W, Su L, Sun Z, Chen L. MD simulation study of the diffusion and local structure of n-alkanes in liquid and supercritical methanol at infinite dilution. J Mol Model 2017; 23:195. [PMID: 28560578 DOI: 10.1007/s00894-017-3366-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 05/09/2017] [Indexed: 10/19/2022]
Abstract
The diffusion coefficients of 14 n-alkanes (ranging from methane to n-tetradecane) in liquid and supercritical methanol at infinite dilution (at a pressure of 10.5 MPa and at temperatures of 299 K and 515 K) were deduced via molecular dynamics simulations. Values for the radial distribution function, coordination number, and number of hydrogen bonds were then calculated to explore the local structure of each fluid. The flexibility of the n-alkane (as characterized by the computed dihedral distribution, end-to-end distance, and radius of gyration) was found to be a major influence and hydrogen bonding to be a minor influence on the local structure. Hydrogen bonding reduces the flexibility of the n-alkane, whereas increasing the temperature enhances its flexibility, with temperature having a greater effect than hydrogen bonding on flexibility. Graphical abstract The flexibility of the alkane is a major influence and the hydrogen bonding is a minor influence on the first solvation shell; the coordination numbers of long-chain n-alkanes in the first solvation shell are rather low.
Collapse
Affiliation(s)
- Huajie Feng
- School of Chemistry and Chemical Engineering, Hainan Normal University, Haikou, 571158, People's Republic of China
| | - Wei Gao
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou, 510006, People's Republic of China
| | - Li Su
- Hainan Entry-Exit Inspection and Quarantine Technology Center, Haikou, 570311, People's Republic of China
| | - Zhenfan Sun
- School of Chemistry and Chemical Engineering, Hainan Normal University, Haikou, 571158, People's Republic of China.
| | - Liuping Chen
- KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China.
| |
Collapse
|
22
|
Girard E, Tassaing T, Marty JD, Destarac M. Structure-Property Relationships in CO2-philic (Co)polymers: Phase Behavior, Self-Assembly, and Stabilization of Water/CO2 Emulsions. Chem Rev 2016; 116:4125-69. [PMID: 27014998 DOI: 10.1021/acs.chemrev.5b00420] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This Review provides comprehensive guidelines for the design of CO2-philic copolymers through an exhaustive and precise coverage of factors governing the solubility of different classes of polymers. Starting from computational calculations describing the interactions of CO2 with various functionalities, we describe the phase behavior in sc-CO2 of the main families of polymers reported in literature. The self-assembly of amphiphilic copolymers of controlled architecture in supercritical carbon dioxide and their use as stabilizers for water/carbon dioxide emulsions then are covered. The relationships between the structure of such materials and their behavior in solutions and at interfaces are systematically underlined throughout these sections.
Collapse
Affiliation(s)
- Etienne Girard
- IMRCP, UMR CNRS 5623, Université de Toulouse , 118, route de Narbonne, Toulouse F-31062 Cedex 9, France
| | - Thierry Tassaing
- ISM, UMR CNRS 5255, Université de Bordeaux , 351, Cours de la Libération, Talence F-33405 Cedex, France
| | - Jean-Daniel Marty
- IMRCP, UMR CNRS 5623, Université de Toulouse , 118, route de Narbonne, Toulouse F-31062 Cedex 9, France
| | - Mathias Destarac
- IMRCP, UMR CNRS 5623, Université de Toulouse , 118, route de Narbonne, Toulouse F-31062 Cedex 9, France
| |
Collapse
|
23
|
|
24
|
Sykora D, Vozka J, Tesarova E. Chromatographic methods enabling the characterization of stationary phases and retention prediction in high-performance liquid chromatography and supercritical fluid chromatography. J Sep Sci 2015; 39:115-31. [DOI: 10.1002/jssc.201501023] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/08/2015] [Accepted: 10/08/2015] [Indexed: 11/11/2022]
Affiliation(s)
- David Sykora
- Department of Analytical Chemistry; University of Chemistry and Technology; Prague Czech Republic
| | - Jiri Vozka
- Department of Analytical Chemistry; University of Chemistry and Technology; Prague Czech Republic
- Department of Physical and Macromolecular Chemistry, Faculty of Science; Charles University in Prague; Prague Czech Republic
| | - Eva Tesarova
- Department of Physical and Macromolecular Chemistry, Faculty of Science; Charles University in Prague; Prague Czech Republic
| |
Collapse
|
25
|
Weng L, Elliott GD. Dynamic and thermodynamic characteristics associated with the glass transition of amorphous trehalose-water mixtures. Phys Chem Chem Phys 2015; 16:11555-65. [PMID: 24803351 DOI: 10.1039/c3cp55418j] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The glass transition temperature Tg of biopreservative formulations is important for predicting the long-term storage of biological specimens. As a complementary tool to thermal analysis techniques, which are the mainstay for determining Tg, molecular dynamics simulations have been successfully applied to predict the Tg of several protectants and their mixtures with water. These molecular analyses, however, rarely focused on the glass transition behavior of aqueous trehalose solutions, a subject that has attracted wide scientific attention via experimental approaches. Important behavior, such as hydrogen-bonding dynamics and self-aggregation has yet to be explored in detail, particularly below, or in the vicinity of, Tg. Using molecular dynamics simulations of several dynamic and thermodynamic properties, this study reproduced the supplemented phase diagram of trehalose-water mixtures (i.e., Tg as a function of the solution composition) based on experimental data. The structure and dynamics of the hydrogen-bonding network in the trehalose-water systems were also analyzed. The hydrogen-bonding lifetime was determined to be an order of magnitude higher in the glassy state than in the liquid state, while the constitution of the hydrogen-bonding network exhibited no noticeable change through the glass transition. It was also found that trehalose molecules preferred to form small, scattered clusters above Tg, but self-aggregation was substantially increased below Tg. The average cluster size in the glassy state was observed to be dependent on the trehalose concentration. Our findings provided insights into the glass transition characteristics of aqueous trehalose solutions as they relate to biopreservation.
Collapse
Affiliation(s)
- Lindong Weng
- Department of Mechanical Engineering and Engineering Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, U.S.A.
| | | |
Collapse
|
26
|
Distinctly Different Glass Transition Behaviors of Trehalose Mixed with Na2HPO 4 or NaH 2PO 4: Evidence for its Molecular Origin. Pharm Res 2014; 32:2217-28. [PMID: 25537342 DOI: 10.1007/s11095-014-1610-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 12/15/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE The present study is aimed at understanding how the interactions between sugar molecules and phosphate ions affect the glass transition temperature of their mixtures, and the implications for pharmaceutical formulations. METHODS The glass transition temperature (Tg) and the α-relaxation temperature (Tα) of dehydrated trehalose/sodium phosphate mixtures (monobasic or dibasic) were determined by differential scanning calorimetry and dynamic mechanical analysis, respectively. Molecular dynamics simulations were also conducted to investigate the microscopic interactions between sugar molecules and phosphate ions. The hydrogen-bonding characteristics and the self-aggregation features of these mixtures were quantified and compared. RESULTS Thermal analysis measurements demonstrated that the addition of NaH2PO4 decreased both the glass transition temperature and the α-relaxation temperature of the dehydrated trehalose/NaH2PO4 mixture compared to trehalose alone while both Tg and Tα were increased by adding Na2HPO4 to pure trehalose. The hydrogen-bonding interactions between trehalose and HPO4(2-) were found to be stronger than both the trehalose-trehalose hydrogen bonds and those formed between trehalose and H2PO4(-). The HPO4(2-) ions also aggregated into smaller clusters than H2PO4(-) ions. CONCLUSIONS The trehalose/Na2HPO4 mixture yielded a higher T g than pure trehalose because marginally self-aggregated HPO4(2-) ions established a strengthened hydrogen-bonding network with trehalose molecules. In contrast H2PO4(-) ions served only as plasticizers, resulting in a lower Tg of the mixtures than trehalose alone, creating large-sized ionic pockets, weakening interactions, and disrupting the original hydrogen-bonding network amongst trehalose molecules.
Collapse
|
27
|
Weng L, Elliott GD. Polymerization effect of electrolytes on hydrogen-bonding cryoprotectants: ion-dipole interactions between metal ions and glycerol. J Phys Chem B 2014; 118:14546-54. [PMID: 25405831 PMCID: PMC4266337 DOI: 10.1021/jp5105533] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Protectants which are cell membrane
permeable, such as glycerol,
have been used effectively in the cryopreservation field for a number
of decades, for both slow cooling and vitrification applications.
In the latter case, the glass transition temperature (Tg) of the vitrification composition is key to its application,
dictating the ultimate storage conditions. It has been observed that
the addition of some electrolytes to glycerol, such as MgCl2, could elevate the Tg of the mixture,
thus potentially providing more storage condition flexibility. The
microscopic mechanisms that give rise to the Tg-enhancing behavior of these electrolytes are not yet well
understood. The current study focuses on molecular dynamics simulation
of glycerol mixed with a variety of metal chlorides (i.e., NaCl, KCl,
MgCl2, and CaCl2), covering a temperature range
that spans both the liquid and glassy states. The characteristics
of the ion–dipole interactions between metal cations and hydroxyl
groups of glycerol were analyzed. The interruption of the original
hydrogen-bonding network among glycerol molecules by the addition
of ions was also investigated in the context of hydrogen-bonding quantity
and lifetime. Divalent metal cations were found to significantly increase
the Tg by strengthening the interacting
network in the electrolyte/glycerol mixture via strong cation–dipole
attractions. In contrast, monovalent cations increased the Tg insignificantly, as the cation–dipole
attraction was only slightly stronger than the original hydrogen-bonding
network among glycerol molecules. The precursor of crystallization
of NaCl and KCl was also observed in these compositions, potentially
contributing to weak Tg-enhancing ability.
The Tg-enhancing mechanisms elucidated
in this study suggest a structure-enhancing role for divalent ions
that could be of benefit in the design of protective formulations
for biopreservation purposes.
Collapse
Affiliation(s)
- Lindong Weng
- Department of Mechanical Engineering and Engineering Sciences, University of North Carolina at Charlotte , Charlotte, North Carolina 28223, United States
| | | |
Collapse
|
28
|
Guardia E, Skarmoutsos I, Masia M. Hydrogen Bonding and Related Properties in Liquid Water: A Car–Parrinello Molecular Dynamics Simulation Study. J Phys Chem B 2014; 119:8926-38. [DOI: 10.1021/jp507196q] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Elvira Guardia
- Departament
de Física i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Campus Nord B4−B5, Barcelona 08034, Spain
| | - Ioannis Skarmoutsos
- Departament
de Física i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Campus Nord B4−B5, Barcelona 08034, Spain
- INAC/SPrAM (UMR 5819 UJF, CNRS, CEA), CEA-Grenoble, 17 Rue des Martyrs, 38054 Grenoble, France
| | - Marco Masia
- Dipartimento
di Chimica e Farmacia, Universita degli Studi di Sassari, Istituto Officina dei Materiali del
CNR, UOS SLACS, Via Vienna 2, 07100 Sassari, Italy
| |
Collapse
|
29
|
Lafrad F, Idrissi A, Tassaing T. What is the state of aggregation of ethanol molecules in ethanol–supercritical carbon dioxide mixtures? An FTIR investigation in the full molar fraction range. J Supercrit Fluids 2014. [DOI: 10.1016/j.supflu.2014.06.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
30
|
Skarmoutsos I, Welton T, Hunt PA. The importance of timescale for hydrogen bonding in imidazolium chloride ionic liquids. Phys Chem Chem Phys 2014; 16:3675-85. [DOI: 10.1039/c3cp54551b] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
31
|
Feng H, Gao W, Sun Z, Lei B, Li G, Chen L. Molecular Dynamics Simulation of Diffusion and Structure of Some n-Alkanes in near Critical and Supercritical Carbon Dioxide at Infinite Dilution. J Phys Chem B 2013; 117:12525-34. [DOI: 10.1021/jp401824d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Huajie Feng
- School
of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158, People’s Republic of China
| | - Wei Gao
- KLGHEI
of Environment and Energy Chemistry, School of Chemistry and Chemical
Engineering, Sun Yat-sen University, Guangzhou 510275, People’s Republic of China
| | - Zhenfan Sun
- School
of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158, People’s Republic of China
| | - Bingxin Lei
- School
of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158, People’s Republic of China
| | - Gaonan Li
- School
of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158, People’s Republic of China
| | - Liuping Chen
- KLGHEI
of Environment and Energy Chemistry, School of Chemistry and Chemical
Engineering, Sun Yat-sen University, Guangzhou 510275, People’s Republic of China
| |
Collapse
|
32
|
Besnard M, Cabaço MI, Coutinho JAP, Danten Y. Assessing the non-ideality of the CO2-CS2 system at molecular level: a Raman scattering study. J Chem Phys 2013; 139:124504. [PMID: 24089783 DOI: 10.1063/1.4821593] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The dense phase of CO2-CS2 mixtures has been analysed by Raman spectroscopy as a function of the CO2 concentration (0.02-0.95 mole fractions) by varying the pressure (0.5 MPa up to 7.7 MPa) at constant temperature (313 K). The polarised and depolarised spectra of the induced (ν2, ν3) modes of CS2 and of the ν1-2ν2 Fermi resonance dyad of both CO2 and CS2 have been measured. Upon dilution with CO2, the evolution of the spectroscopic observables of all these modes displays a "plateau-like" region in the CO2 mole fraction 0.3-0.7 never previously observed in CO2-organic liquids mixtures. The bandshape and intensity of the induced modes of CS2 are similar to those of pure CS2 up to equimolar concentration, after which variations occur. The preservation of the local ordering from pure CS2 to equimolar concentration together with the non-linear evolution of the spectroscopic observables allows inferring that two solvation regimes exist with a transition occurring in the plateau domain. In the first regime, corresponding to CS2 concentrated mixtures, the liquid phase is segregated with dominant CS2 clusters, whereas, in the second one, CO2 monomers and dimers and CO2-CS2 hetero-dimers coexist dynamically on a picosecond time-scale. It is demonstrated that the subtle interplay between attractive and repulsive interactions which provides a molecular interpretation of the non-ideality of the CO2-CS2 mixture allows rationalizing the volume expansion and the existence of the plateau-like region observed in the pressure-composition diagram previously ascribed to the proximity of an upper critical solution temperature at lower temperatures.
Collapse
Affiliation(s)
- M Besnard
- Institut des Sciences Moléculaires, CNRS (UMR 5255), Université Bordeaux 1, 351 Cours de la Libération, 33405 Talence Cedex, France
| | | | | | | |
Collapse
|
33
|
Kajiya D, Saitow KI. Investigation of attractive and repulsive interactions associated with ketones in supercritical CO2, based on Raman spectroscopy and theoretical calculations. J Chem Phys 2013; 139:054509. [DOI: 10.1063/1.4817190] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
|
34
|
Reiser S, McCann N, Horsch M, Hasse H. Hydrogen bonding of ethanol in supercritical mixtures with CO2 by 1H NMR spectroscopy and molecular simulation. J Supercrit Fluids 2012. [DOI: 10.1016/j.supflu.2012.04.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
35
|
Chen C, Li WZ, Song YC, Weng LD, Zhang N. Hydrogen Bonding Analysis of Hydroxyl Groups in Glucose Aqueous Solutions by a Molecular Dynamics Simulation Study. B KOREAN CHEM SOC 2012. [DOI: 10.5012/bkcs.2012.33.7.2238] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
36
|
Lithoxoos GP, Peristeras LD, Boulougouris GC, Economou IG. Monte Carlo simulation of carbon monoxide, carbon dioxide and methane adsorption on activated carbon. Mol Phys 2012. [DOI: 10.1080/00268976.2012.659223] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
37
|
Cabaço MI, Besnard M, Danten Y, Coutinho JAP. Carbon Dioxide in 1-Butyl-3-methylimidazolium Acetate. I. Unusual Solubility Investigated by Raman Spectroscopy and DFT Calculations. J Phys Chem A 2012; 116:1605-20. [DOI: 10.1021/jp211211n] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- M. Isabel Cabaço
- Centro de Física Atómica da UL, Av. Prof. Gama Pinto 2, 1694-003
Lisboa, and Departamento de Física, Instituto Superior Técnico, UTL, Av. Rovisco Pais, 1049-001
Lisboa, Portugal
| | - M. Besnard
- Institut
des Sciences Moléculaires,
CNRS (UMR 5255), Université Bordeaux 1, 351 Cours de la Libération, 33405 Talence Cedex, France
| | - Y. Danten
- Institut
des Sciences Moléculaires,
CNRS (UMR 5255), Université Bordeaux 1, 351 Cours de la Libération, 33405 Talence Cedex, France
| | - J. A. P. Coutinho
- CICECO, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro, Portugal
| |
Collapse
|
38
|
Arul Murugan N, Kongsted J, Rinkevicius Z, Aidas K, Ågren H. Modeling the Structure and Absorption Spectra of Stilbazolium Merocyanine in Polar and Nonpolar Solvents Using Hybrid QM/MM Techniques. J Phys Chem B 2010; 114:13349-57. [DOI: 10.1021/jp1060717] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- N. Arul Murugan
- Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden, Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Department of Chemistry, H. C. ⌀rsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen ⌀, Denmark
| | - Jacob Kongsted
- Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden, Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Department of Chemistry, H. C. ⌀rsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen ⌀, Denmark
| | - Zilvinas Rinkevicius
- Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden, Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Department of Chemistry, H. C. ⌀rsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen ⌀, Denmark
| | - Kestutis Aidas
- Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden, Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Department of Chemistry, H. C. ⌀rsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen ⌀, Denmark
| | - Hans Ågren
- Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden, Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Department of Chemistry, H. C. ⌀rsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen ⌀, Denmark
| |
Collapse
|