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Cruickshank E. The Emergence of a Polar Nematic Phase: A Chemist's Insight into the Ferroelectric Nematic Phase. Chempluschem 2024:e202300726. [PMID: 38452282 DOI: 10.1002/cplu.202300726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/20/2024] [Accepted: 03/07/2024] [Indexed: 03/09/2024]
Abstract
The discovery of a new polar nematic phase; the ferroelectric nematic, has generated a great deal of excitement in the field of liquid crystals. To date there have been around 150 materials reported exhibiting the ferroelectric nematic phase, in general, following three key archetypal structures with these compounds known as RM734, DIO and UUQU-4N. In this review, the relationship between the molecular structure and the stability of the ferroelectric nematic, NF, phase will be described from a chemist's perspective. This will look to highlight the wide variety of functionalities which have been incorporated into these archetypal structures and how these changes influence the transition temperatures of the mesophases present. The NF phase appears to be stabilised particularly by reducing the length of terminal alkyl chains present and adding fluorines laterally along the length of the molecular backbone. This review will look to introduce the background of the ferroelectric nematic phase before then showing the molecular structures of a range of materials which exhibit the phase, describing their structure-property relationships and therefore giving an up-to-date account of the literature for this fascinating new mesophase.
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Affiliation(s)
- Ewan Cruickshank
- School of Pharmacy and Life Sciences, Robert Gordon University, Aberdeen, AB10 7GJ, UK
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Cruickshank E, Rybak P, Majewska MM, Ramsay S, Wang C, Zhu C, Walker R, Storey JMD, Imrie CT, Gorecka E, Pociecha D. To Be or Not To Be Polar: The Ferroelectric and Antiferroelectric Nematic Phases. ACS Omega 2023; 8:36562-36568. [PMID: 37810647 PMCID: PMC10552116 DOI: 10.1021/acsomega.3c05884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 08/30/2023] [Indexed: 10/10/2023]
Abstract
We report two new series of compounds that show the ferroelectric nematic, NF, phase in which the terminal chain length is varied. The longer the terminal chain, the weaker the dipole-dipole interactions of the molecules are along the director and thus the lower the temperature at which the axially polar NF phase is formed. For homologues of intermediate chain lengths, between the non-polar and ferroelectric nematic phases, a wide temperature range nematic phase emerges with antiferroelectric character. The size of the antiparallel ferroelectric domains critically increases upon transition to the NF phase. In dielectric studies, both collective ("ferroelectric") and non-collective fluctuations are present, and the "ferroelectric" mode softens weakly at the N-NX phase transition because the polar order in this phase is weak. The transition to the NF phase is characterized by a much stronger lowering of the mode relaxation frequency and an increase in its strength, and a typical critical behavior is observed.
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Affiliation(s)
- Ewan Cruickshank
- Department
of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, U.K.
| | - Paulina Rybak
- Faculty
of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Magdalena M. Majewska
- Faculty
of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Shona Ramsay
- Department
of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, U.K.
| | - Cheng Wang
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Chenhui Zhu
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Rebecca Walker
- Department
of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, U.K.
| | - John M. D. Storey
- Department
of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, U.K.
| | - Corrie T. Imrie
- Department
of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, U.K.
| | - Ewa Gorecka
- Faculty
of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Damian Pociecha
- Faculty
of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland
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Szydlowska J, Majewski P, Čepič M, Vaupotič N, Rybak P, Imrie CT, Walker R, Cruickshank E, Storey JMD, Damian P, Gorecka E. Ferroelectric Nematic-Isotropic Liquid Critical End Point. Phys Rev Lett 2023; 130:216802. [PMID: 37295101 DOI: 10.1103/physrevlett.130.216802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/18/2023] [Indexed: 06/12/2023]
Abstract
A critical end point above which an isotropic phase continuously evolves into a polar (ferroelectric) nematic phase with an increasing electric field is found in a ferroelectric nematic liquid crystalline material. The critical end point is approximately 30 K above the zero-field transition temperature from the isotropic to nematic phase and at an electric field of the order of 10 V/μm. Such systems are interesting from the application point of view because a strong birefringence can be induced in a broad temperature range in an optically isotropic phase.
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Affiliation(s)
- Jadwiga Szydlowska
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Pawel Majewski
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Mojca Čepič
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Department of Physics and Technical Studies, Faculty of Education, University of Ljubljana, Kardeljeva ploščad 16, 1000 Ljubljana, Slovenia
| | - Nataša Vaupotič
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška 160, 2000 Maribor, Slovenia
| | - Paulina Rybak
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Corrie T Imrie
- Department of Chemistry, University of Aberdeen, Old Aberdeen AB24 3UE, United Kingdom
| | - Rebecca Walker
- Department of Chemistry, University of Aberdeen, Old Aberdeen AB24 3UE, United Kingdom
| | - Ewan Cruickshank
- Department of Chemistry, University of Aberdeen, Old Aberdeen AB24 3UE, United Kingdom
| | - John M D Storey
- Department of Chemistry, University of Aberdeen, Old Aberdeen AB24 3UE, United Kingdom
| | - Pociecha Damian
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Ewa Gorecka
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
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Tufaha N, Cruickshank E, Pociecha D, Gorecka E, Storey JM, Imrie CT. Molecular Shape, Electronic Factors, and the Ferroelectric Nematic Phase: Investigating the Impact of Structural Modifications. Chemistry 2023; 29:e202300073. [PMID: 36807424 PMCID: PMC10962687 DOI: 10.1002/chem.202300073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023]
Abstract
The synthesis and characterisation of two series of low molar mass mesogens, the (4-nitrophenyl) 2-alkoxy-4-(4-methoxybenzoyl)oxybenzoates (NT3.m) and the (3-fluoro-4-nitrophenyl) 2-alkoxy-4-(4-methoxybenzoyl)oxybenzoates (NT3F.m), are reported in order to investigate the effect of changing the position of a lateral alkoxy chain from the methoxy-substituted terminal ring to the central phenyl ring in these two series of materials based on RM734. All members of the NT3.m series exhibited a conventional nematic phase, N, which preceded the ferroelectric nematic phase, NF , whereas all the members of the NT3F.m series exhibited direct NF -I transitions except for NT3F.1 which also exhibited an N phase. These materials cannot be described as wedge-shaped, yet their values of the ferroelectric nematic-nematic transition temperature, TN F N ${{_{{\rm N}{_{{\rm F}}}{\rm N}}}}$ , exceed those of the corresponding materials with the lateral alkoxy chain located on the methoxy-substituted terminal ring. In part, this may be attributed to the effect that changing the position of the lateral alkoxy chain has on the electronic properties of these materials, specifically on the electron density associated with the methoxy-substituted terminal aromatic ring. The value of TNI decreased with the addition of a fluorine atom ortho to the nitro group in NT3F.1, however, the opposite behaviour was found when the transition temperatures of the NF phase were compared which are higher for the NT3F.m series. This may reflect a change in the polarity and polarizability of the NT3F.m series compared to the NT3.m series. Therefore, it is suggested that, rather than simply promoting a tapered shape, the role of the lateral chain in inhibiting anti-parallel associations and its effect on the electronic properties of the molecules are the key factors in driving the formation of the NF phase.
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Affiliation(s)
- Naila Tufaha
- Department of ChemistryUniversity of AberdeenOld AberdeenAB24 3UEUK
| | - Ewan Cruickshank
- Department of ChemistryUniversity of AberdeenOld AberdeenAB24 3UEUK
| | - Damian Pociecha
- Faculty of ChemistryUniversity of Warsawul. Zwirki i Wigury 10102-089WarsawPoland
| | - Ewa Gorecka
- Faculty of ChemistryUniversity of Warsawul. Zwirki i Wigury 10102-089WarsawPoland
| | - John M.D. Storey
- Department of ChemistryUniversity of AberdeenOld AberdeenAB24 3UEUK
| | - Corrie T. Imrie
- Department of ChemistryUniversity of AberdeenOld AberdeenAB24 3UEUK
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Cruickshank E, Strachan GJ, Majewska M, Pociecha D, Gorecka E, Storey JMD, Imrie CT. The effects of alkylthio chains on the properties of symmetric liquid crystal dimers. NEW J CHEM 2023. [DOI: 10.1039/d2nj06252f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2023]
Abstract
The synthesis and characterisation of four series of symmetric liquid crystal dimers containing either alkylthio or alkyloxy terminal chains are reported. The (E,E)-[pentane-1,5-diylbis(oxy-4,1-phenylene)]bis{N-[4-(alkyloxy)phenyl]methanimine}s, mO.O5O.Om and (E,E)-[hexane-1,6-diylbis(oxy-4,1-phenylene)]bis{N-[4-(alkyloxy)phenyl]methanimine}s, mO.O6O.Om series are nematogenic...
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Cruickshank E, Walker R, Storey JMD, Imrie CT. The effect of a lateral alkyloxy chain on the ferroelectric nematic phase. RSC Adv 2022; 12:29482-29490. [PMID: 36320775 PMCID: PMC9562421 DOI: 10.1039/d2ra05628c] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 10/06/2022] [Indexed: 11/05/2022] Open
Abstract
The synthesis and characterisation of two series of low molar mass liquid crystals, the 4-[(4-nitrophenoxy)carbonyl]phenyl 2-alkoxy-4-methoxybenzoates (series 5-m) and the 4-[(3-fluoro-4-nitrophenoxy)carbonyl]phenyl 2-alkoxy-4-methoxybenzoates (series 6-m) are reported in order to explore the effects of a lateral alkyloxy chain on the formation and stability of the recently discovered ferroelectric nematic phase. In both series m, the number of carbon atoms in the lateral chain, is varied from one to nine. The two series differ by the addition of a fluorine substituent in the 6-m series. 5-1 is the extensively studied ferroelectric nematogen RM734. All the members of the 5-m series exhibited both a conventional nematic, N, and ferroelectric nematic, NF, phase, whereas all the members of the 6-m series exhibit a direct NF-I transition with the exception of 6-1 that also exhibits a N phase. The replacement of a hydrogen atom by a fluorine atom reduces the nematic-isotropic transition temperature, T NI, whereas the ferroelectric nematic-nematic, or isotropic, transition temperature, T NFN/I, increases. This is interpreted in terms of the reduced structural anisotropy associated with the larger fluorine atom whereas the increase in the stability of the NF phase reflects changes in polarity and polarizability. The dependence of T NI and T NFN/I on m in both series is similar, and these initially decrease on increasing m but converge to limiting values on further increasing m. This suggests that the lateral alkyloxy chain may adopt conformations in which it lies along the major axis of the mesogenic unit.
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Affiliation(s)
- Ewan Cruickshank
- Department of Chemistry, University of AberdeenOld AberdeenAB24 3UEUK
| | - Rebecca Walker
- Department of Chemistry, University of AberdeenOld AberdeenAB24 3UEUK
| | - John M. D. Storey
- Department of Chemistry, University of AberdeenOld AberdeenAB24 3UEUK
| | - Corrie T. Imrie
- Department of Chemistry, University of AberdeenOld AberdeenAB24 3UEUK
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Pociecha D, Walker R, Cruickshank E, Szydlowska J, Rybak P, Makal A, Matraszek J, Wolska JM, Storey JM, Imrie CT, Gorecka E. Intrinsically chiral ferronematic liquid crystals: An inversion of the helical twist sense at the chiral nematic – Chiral ferronematic phase transition. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119532] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Cruickshank E, Strachan GJ, Storey JMD, Imrie CT. Chalcogen bonding and liquid crystallinity: Understanding the anomalous behaviour of the 4′-(alkylthio)[1,1′-biphenyl]-4-carbonitriles (nSCB). J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.117094] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Brown S, Cruickshank E, Storey JMD, Imrie CT, Pociecha D, Majewska M, Makal A, Gorecka E. Multiple Polar and Non-polar Nematic Phases. Chemphyschem 2021; 22:2506-2510. [PMID: 34623724 DOI: 10.1002/cphc.202100644] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/08/2021] [Indexed: 11/09/2022]
Abstract
Liquid-crystal materials exhibiting up to three nematic phases are reported. Dielectric response measurements show that while the lower temperature nematic phase has ferroelectric order and the highest temperature nematic phase is apolar, the intermediate phase has local antiferroelectric order. The modification of the molecular structure by increasing the number of lateral fluorine substituents leads to one of the materials showing a direct isotropic- ferronematic phase transition.
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Affiliation(s)
- Stevie Brown
- Department of Chemistry, University of Aberdeen, Old Aberdeen, AB24 3UE, U.K
| | - Ewan Cruickshank
- Department of Chemistry, University of Aberdeen, Old Aberdeen, AB24 3UE, U.K
| | - John M D Storey
- Department of Chemistry, University of Aberdeen, Old Aberdeen, AB24 3UE, U.K
| | - Corrie T Imrie
- Department of Chemistry, University of Aberdeen, Old Aberdeen, AB24 3UE, U.K
| | - Damian Pociecha
- Department of Chemistry, University of Warsaw, Zwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Magdalena Majewska
- Department of Chemistry, University of Warsaw, Zwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Anna Makal
- Department of Chemistry, University of Warsaw, Zwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Ewa Gorecka
- Department of Chemistry, University of Warsaw, Zwirki i Wigury 101, 02-089, Warsaw, Poland
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Pociecha D, Vaupotič N, Majewska M, Cruickshank E, Walker R, Storey JMD, Imrie CT, Wang C, Gorecka E. Photonic Bandgap in Achiral Liquid Crystals-A Twist on a Twist. Adv Mater 2021; 33:e2103288. [PMID: 34396593 DOI: 10.1002/adma.202103288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/22/2021] [Indexed: 06/13/2023]
Abstract
Achiral mesogenic molecules are shown to be able to spontaneously assemble into liquid crystalline smectic phases having either simple or double-helical structures. At the transition between these phases, the double-helical structure unwinds. As a consequence, in some temperature range, the pitch of the helix becomes comparable to the wavelength of visible light and the selective reflection of light in the visible range is observed. The photonic bandgap phenomenon is reported for achiral liquid crystals.
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Affiliation(s)
- Damian Pociecha
- Faculty of Chemistry, University of Warsaw, Zwirki i Wigury 101, Warsaw, 02-089, Poland
| | - Nataša Vaupotič
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška 160, Maribor, 2000, Slovenia
- Jozef Stefan Institute, Jamova 39, Ljubljana, 1000, Slovenia
| | - Magdalena Majewska
- Faculty of Chemistry, University of Warsaw, Zwirki i Wigury 101, Warsaw, 02-089, Poland
| | - Ewan Cruickshank
- Department of Chemistry, King's College, University of Aberdeen, Aberdeen, AB24 3UE, UK
| | - Rebecca Walker
- Department of Chemistry, King's College, University of Aberdeen, Aberdeen, AB24 3UE, UK
| | - John M D Storey
- Department of Chemistry, King's College, University of Aberdeen, Aberdeen, AB24 3UE, UK
| | - Corrie T Imrie
- Department of Chemistry, King's College, University of Aberdeen, Aberdeen, AB24 3UE, UK
| | - Cheng Wang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ewa Gorecka
- Faculty of Chemistry, University of Warsaw, Zwirki i Wigury 101, Warsaw, 02-089, Poland
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Forsyth E, Paterson DA, Cruickshank E, Strachan GJ, Gorecka E, Walker R, Storey JM, Imrie CT. Liquid crystal dimers and the twist-bend nematic phase: On the role of spacers and terminal alkyl chains. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114391] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Abstract
OBJECTIVE To examine the periapical status, technical standard and frequency of root canal treatment in an adult population in Scotland. DESIGN Examination of full-mouth periapical radiographs from 340 consecutive adult patients (8420 teeth) attending Glasgow and Dundee Dental Hospitals for clinical examination. METHODS Position and quality of the root fillings were assessed together with signs of periradicular radiolucencies. The influence of the type of coronal restoration was also assessed. MAIN OUTCOME MEASURES Pathologies associated with impacted third molars and outcomes following surgical removal of third molars. RESULTS 54% of the patient sample had root filled teeth. 5.6% of the teeth examined radiographically had root fillings, and of these, 58.1% had radiographic signs of periapical disease. 41% of the patients had at least one non-root canal treated tooth with periapical disease. 77% of teeth with post-retained crowns had evidence of periapical pathology. CONCLUSIONS Root fillings judged to be adequate radiographically had a reduced incidence of radiolucencies. Teeth obturated beyond the apex had more radiolucencies than those obturated flush with or within 2 mm of the radiographic apex. A high proportion of post-retained crowns were associated with periapical pathology. There is a substantial future need both for root canal treatment and for standardised treatment methods.
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Affiliation(s)
- W P Saunders
- University of Glasgow Dental School, United Kingdom
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Cruickshank E. Cicely D. Williams, grand lady of medicine. Nutr Rev 1973; 31:378-81. [PMID: 4587994 DOI: 10.1111/j.1753-4887.1973.tb07058.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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