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Volumn 31, Issue 9, 2015, Pages 1096-1102

Cellulose aerogels from cellulose-NaOH/PEG solution and comparison with different cellulose contents

Author keywords

Cellulose aerogels; Freeze drying; NaOH PEG solution; Oil adsorption; Polymers

Indexed keywords

CELLULOSE; CRYSTALLINITY; GAS ADSORPTION; LOW TEMPERATURE DRYING; POLYMERS; SCANNING ELECTRON MICROSCOPY; SODIUM HYDROXIDE; THERMOGRAVIMETRIC ANALYSIS;

EID: 84937415255     PISSN: 02670836     EISSN: 17432847     Source Type: Journal    
DOI: 10.1179/1743284714Y.0000000677     Document Type: Article
Times cited : (24)

References (44)
  • 1
    • 0030678872 scopus 로고    scopus 로고
    • Porous structure of organic and carbon aerogels synthesized by sol-gel polycondensation of resorcinol with formaldehyde
    • H. Tamon, H. Ishizaka, M. Mikami and M. Okazaki: 'Porous structure of organic and carbon aerogels synthesized by sol-gel polycondensation of resorcinol with formaldehyde', Carbon, 1997, 35, (6), 791-796.
    • (1997) Carbon , vol.35 , Issue.6 , pp. 791-796
    • Tamon, H.1    Ishizaka, H.2    Mikami, M.3    Okazaki, M.4
  • 2
    • 33645048115 scopus 로고
    • Correlation between structure and thermal conductivity of organic aerogels
    • X. Lu, R. Caps, J. Fricke, C. Alviso and R. Pekala: 'Correlation between structure and thermal conductivity of organic aerogels', J. Non-Cryst. Solids, 1995, 188, (3), 226-234.
    • (1995) J. Non-Cryst. Solids , vol.188 , Issue.3 , pp. 226-234
    • Lu, X.1    Caps, R.2    Fricke, J.3    Alviso, C.4    Pekala, R.5
  • 3
    • 58149365165 scopus 로고
    • Relationship between optical transparency and nanostructural features of silica aerogels
    • A. Emmerling, R. Petricevic, A. Beck, P. Wang, H. Scheller and J. Fricke: 'Relationship between optical transparency and nanostructural features of silica aerogels', J. Non-Cryst. Solids, 1995, 185, (3), 240-248.
    • (1995) J. Non-Cryst. Solids , vol.185 , Issue.3 , pp. 240-248
    • Emmerling, A.1    Petricevic, R.2    Beck, A.3    Wang, P.4    Scheller, H.5    Fricke, J.6
  • 4
    • 34247505686 scopus 로고
    • Thin aerogel films for optical, thermal, acoustic and electronic applications
    • L. W. Hrubesh and J. F. Poco: 'Thin aerogel films for optical, thermal, acoustic and electronic applications', J. Non-Cryst. Solids, 1995, 188, (1), 46-53.
    • (1995) J. Non-Cryst. Solids , vol.188 , Issue.1 , pp. 46-53
    • Hrubesh, L.W.1    Poco, J.F.2
  • 5
    • 84891345128 scopus 로고    scopus 로고
    • High strain recovery with improved mechanical properties of gelatin-silica aerogel composites post-binding treatment
    • M. Sachithanadam and S. Joshi: 'High strain recovery with improved mechanical properties of gelatin-silica aerogel composites post-binding treatment', J. Mater. Sci., 2014, 49, (1), 163-179.
    • (2014) J. Mater. Sci. , vol.49 , Issue.1 , pp. 163-179
    • Sachithanadam, M.1    Joshi, S.2
  • 6
    • 25844469936 scopus 로고    scopus 로고
    • Removal of heavy metal ions from aqueous solutions using carbon aerogel as an adsorbent
    • A. K. Meena, G. Mishra, P. Rai, C. Rajagopal and P. Nagar: 'Removal of heavy metal ions from aqueous solutions using carbon aerogel as an adsorbent', J. Hazard. Mater., 2005, 122, (1), 161-170.
    • (2005) J. Hazard. Mater. , vol.122 , Issue.1 , pp. 161-170
    • Meena, A.K.1    Mishra, G.2    Rai, P.3    Rajagopal, C.4    Nagar, P.5
  • 7
    • 0026154612 scopus 로고
    • Aerogel catalysts
    • G. Pajonk: 'Aerogel catalysts', Appl. Catal., 1991, 72, (2), 217-266.
    • (1991) Appl. Catal. , vol.72 , Issue.2 , pp. 217-266
    • Pajonk, G.1
  • 9
    • 0035369566 scopus 로고    scopus 로고
    • Effect of methyltrimethoxysilane as a co-precursor on the optical properties of silica aerogels
    • A. Venkateswara Rao and G. Pajonk: 'Effect of methyltrimethoxysilane as a co-precursor on the optical properties of silica aerogels', J. Non-Cryst. Solids, 2001, 285, (1), 202-209.
    • (2001) J. Non-Cryst. Solids , vol.285 , Issue.1 , pp. 202-209
    • Venkateswara Rao, A.1    Pajonk, G.2
  • 11
    • 16244372114 scopus 로고    scopus 로고
    • Preparation of carbon aerogel electrodes for supercapacitor and their electrochemical characteristics
    • S. J. Kim, S. W. Hwang and S. H. Hyun: 'Preparation of carbon aerogel electrodes for supercapacitor and their electrochemical characteristics', J. Mater. Sci., 2005, 40, (3), 725-731.
    • (2005) J. Mater. Sci. , vol.40 , Issue.3 , pp. 725-731
    • Kim, S.J.1    Hwang, S.W.2    Hyun, S.H.3
  • 12
    • 0038515002 scopus 로고    scopus 로고
    • Effect of mixing on thermal and mechanical properties of aerogel-PVB composites
    • G. S. Kim and S. H. Hyun: 'Effect of mixing on thermal and mechanical properties of aerogel-PVB composites', J. Mater. Sci., 2003, 38, (9), 1961-1966.
    • (2003) J. Mater. Sci. , vol.38 , Issue.9 , pp. 1961-1966
    • Kim, G.S.1    Hyun, S.H.2
  • 13
    • 50249165465 scopus 로고    scopus 로고
    • Development of micro-and nano-porous composite materials by processing cellulose with ionic liquids and supercritical CO 2
    • C. Tsioptsias, A. Stefopoulos, I. Kokkinomalis, L. Papadopoulou and C. Panayiotou: 'Development of micro-and nano-porous composite materials by processing cellulose with ionic liquids and supercritical CO 2', Green Chem., 2008, 10, (9), 965-971.
    • (2008) Green Chem. , vol.10 , Issue.9 , pp. 965-971
    • Tsioptsias, C.1    Stefopoulos, A.2    Kokkinomalis, I.3    Papadopoulou, L.4    Panayiotou, C.5
  • 14
    • 77954584209 scopus 로고    scopus 로고
    • Aerogels from nanofibrillated cellulose with tunable oleophobicity
    • C. Aulin, J. Netrval, L. Wagberg and T. Lindstrom: 'Aerogels from nanofibrillated cellulose with tunable oleophobicity', Soft Matter, 2010, 6, (14), 3298-3305.
    • (2010) Soft Matter , vol.6 , Issue.14 , pp. 3298-3305
    • Aulin, C.1    Netrval, J.2    Wagberg, L.3    Lindstrom, T.4
  • 15
    • 84862828664 scopus 로고    scopus 로고
    • Theoretical and experimental investigation on dissolution and regeneration of cellulose in ionic liquid
    • Z.-D. Ding, Z. Chi, W.-X. Gu, S.-M. Gu, J.-H. Liu and H.-J. Wang: 'Theoretical and experimental investigation on dissolution and regeneration of cellulose in ionic liquid', Carbohydr. Polym., 2012, 89, (1), 7-16.
    • (2012) Carbohydr. Polym. , vol.89 , Issue.1 , pp. 7-16
    • Ding, Z.-D.1    Chi, Z.2    Gu, W.-X.3    Gu, S.-M.4    Liu, J.-H.5    Wang, H.-J.6
  • 16
    • 79960062324 scopus 로고    scopus 로고
    • Enhancement of cellulose dissolution in water-based solvent via ethanol-hydrochloric acid pretreatment
    • J. Trygg and P. Fardim: 'Enhancement of cellulose dissolution in water-based solvent via ethanol-hydrochloric acid pretreatment', Cellulose, 2011, 18, (4), 987-994.
    • (2011) Cellulose , vol.18 , Issue.4 , pp. 987-994
    • Trygg, J.1    Fardim, P.2
  • 17
    • 0026617252 scopus 로고
    • Formation and characterization of the fibres and films from mesophase solutions of cellulose in ammonia/ammonium thiocyanate solvent
    • K. S. Yang, M. H. Theil, Y. S. Chen and J. A. Cuculo: 'Formation and characterization of the fibres and films from mesophase solutions of cellulose in ammonia/ammonium thiocyanate solvent', Polymer, 1992, 33, (1), 170-174.
    • (1992) Polymer , vol.33 , Issue.1 , pp. 170-174
    • Yang, K.S.1    Theil, M.H.2    Chen, Y.S.3    Cuculo, J.A.4
  • 18
    • 85011675907 scopus 로고
    • The porous structure of cellulose gel regenerated from calcium thiocyanate solution
    • S. Kuga: 'The porous structure of cellulose gel regenerated from calcium thiocyanate solution', J. Colloid Interface Sci., 1980, 77, (2), 413-417.
    • (1980) J. Colloid Interface Sci. , vol.77 , Issue.2 , pp. 413-417
    • Kuga, S.1
  • 19
    • 30344464689 scopus 로고    scopus 로고
    • Mercerized linters cellulose: Characterization and acetylation in N,N-dimethylacetamide/ lithium chloride
    • B. A. P. Ass, M. N. Belgacem and E. Frollini: 'Mercerized linters cellulose: characterization and acetylation in N,N-dimethylacetamide/ lithium chloride', Carbohydr. Polym., 2006, 63, (1), 19-29.
    • (2006) Carbohydr. Polym. , vol.63 , Issue.1 , pp. 19-29
    • Ass, B.A.P.1    Belgacem, M.N.2    Frollini, E.3
  • 20
    • 1642488898 scopus 로고    scopus 로고
    • Calculated phase diagrams for cellulose/ ammonia/ammonium thiocyanate solutions in comparison to experimental results
    • M. Frey and M. Theil: 'Calculated phase diagrams for cellulose/ ammonia/ammonium thiocyanate solutions in comparison to experimental results', Cellulose, 2004, 11, (1), 53-63.
    • (2004) Cellulose , vol.11 , Issue.1 , pp. 53-63
    • Frey, M.1    Theil, M.2
  • 21
    • 84894080394 scopus 로고    scopus 로고
    • Effect of methylimidazole on cellulose/ionic liquid solutions and regenerated material therefrom
    • C. Olsson, A. Hedlund, A. Idström and G. Westman: 'Effect of methylimidazole on cellulose/ionic liquid solutions and regenerated material therefrom', J. Mater. Sci., 2014, 49, (9), 3423-3433.
    • (2014) J. Mater. Sci. , vol.49 , Issue.9 , pp. 3423-3433
    • Olsson, C.1    Hedlund, A.2    Idström, A.3    Westman, G.4
  • 22
    • 84862569977 scopus 로고    scopus 로고
    • Fabrication of mesoporous lignocellulose aerogels from wood via cyclic liquid nitrogen freezing-thawing in ionic liquid solution
    • Y. Lu, Q. Sun, D. Yang, X. She, X. Yao, G. Zhu, Y. Liu, H. Zhao and J. Li: 'Fabrication of mesoporous lignocellulose aerogels from wood via cyclic liquid nitrogen freezing-thawing in ionic liquid solution', J. Mater. Chem., 2012, 22, (27), 13548-13557.
    • (2012) J. Mater. Chem. , vol.22 , Issue.27 , pp. 13548-13557
    • Lu, Y.1    Sun, Q.2    Yang, D.3    She, X.4    Yao, X.5    Zhu, G.6    Liu, Y.7    Zhao, H.8    Li, J.9
  • 23
    • 34547239371 scopus 로고    scopus 로고
    • Rheological behavior of chitosan derivative/cellulose polyblends from N-methylmorpholine N-oxide/ H2O solution
    • X. Liu, Q. Chen and H. Pan: 'Rheological behavior of chitosan derivative/cellulose polyblends from N-methylmorpholine N-oxide/ H2O solution', J. Mater. Sci., 2007, 42, (16), 6510-6514.
    • (2007) J. Mater. Sci. , vol.42 , Issue.16 , pp. 6510-6514
    • Liu, X.1    Chen, Q.2    Pan, H.3
  • 24
    • 54949099202 scopus 로고    scopus 로고
    • Dissolving of cellulose in PEG/NaOH aqueous solution
    • L. Yan and Z. Gao: 'Dissolving of cellulose in PEG/NaOH aqueous solution', Cellulose, 2008, 15, (6), 789-796.
    • (2008) Cellulose , vol.15 , Issue.6 , pp. 789-796
    • Yan, L.1    Gao, Z.2
  • 25
    • 71649092891 scopus 로고    scopus 로고
    • Preparation of all-cellulose composite by selective dissolving of cellulose surface in PEG/NaOH aqueous solution
    • D. Han and L. Yan: 'Preparation of all-cellulose composite by selective dissolving of cellulose surface in PEG/NaOH aqueous solution', Carbohydr. Polym., 2010, 79, (3), 614-619.
    • (2010) Carbohydr. Polym. , vol.79 , Issue.3 , pp. 614-619
    • Han, D.1    Yan, L.2
  • 26
    • 14644420299 scopus 로고    scopus 로고
    • Polyethylene glycol and solutions of polyethylene glycol as green reaction media
    • J. Chen, S. K. Spear, J. G. Huddleston and R. D. Rogers: 'Polyethylene glycol and solutions of polyethylene glycol as green reaction media', Green Chem., 2005, 7, (2), 64-82.
    • (2005) Green Chem. , vol.7 , Issue.2 , pp. 64-82
    • Chen, J.1    Spear, S.K.2    Huddleston, J.G.3    Rogers, R.D.4
  • 27
    • 43049161320 scopus 로고    scopus 로고
    • Synthesis of poly (vinyl alcohol)-magnetite ferrogel obtained by freezing-thawing technique
    • P. Resendiz-Hernandez, O. Rodriguez-Fernandez and L. Garcia- Cerda: 'Synthesis of poly (vinyl alcohol)-magnetite ferrogel obtained by freezing-thawing technique', J. Magn. Magn. Mater., 2008, 320, (14), e373-e376.
    • (2008) J. Magn. Magn. Mater. , vol.320 , Issue.14 , pp. e373-e376
    • Resendiz-Hernandez, P.1    Rodriguez-Fernandez, O.2    Garcia- Cerda, L.3
  • 28
    • 76649131567 scopus 로고    scopus 로고
    • Effects of freezing/thawing cycles and cellulose nanowhiskers on structure and properties of biocompatible starch/PVA sponges
    • Y. Wang, C. Chang and L. Zhang: 'Effects of freezing/thawing cycles and cellulose nanowhiskers on structure and properties of biocompatible starch/PVA sponges', Macromol. Mater. Eng., 2010, 295, (2), 137-145.
    • (2010) Macromol. Mater. Eng. , vol.295 , Issue.2 , pp. 137-145
    • Wang, Y.1    Chang, C.2    Zhang, L.3
  • 29
    • 55349129254 scopus 로고    scopus 로고
    • Effects of crosslinking methods on structure and properties of cellulose/PVA hydrogels
    • C. Chang, A. Lue and L. Zhang: 'Effects of crosslinking methods on structure and properties of cellulose/PVA hydrogels', Macromol. Chem. Phys., 2008, 209, (12), 1266-1273.
    • (2008) Macromol. Chem. Phys. , vol.209 , Issue.12 , pp. 1266-1273
    • Chang, C.1    Lue, A.2    Zhang, L.3
  • 30
    • 85034843996 scopus 로고    scopus 로고
    • Fabrication of cellulose aerogel from wheat straw with strong absorptive capacity
    • L. Jian, W. Caichao, L. Yun and S. Qingfeng: 'Fabrication of cellulose aerogel from wheat straw with strong absorptive capacity', Front. Agric. Sci. Eng., 2014, 1, (1), 46-52.
    • (2014) Front. Agric. Sci. Eng. , vol.1 , Issue.1 , pp. 46-52
    • Jian, L.1    Caichao, W.2    Yun, L.3    Qingfeng, S.4
  • 31
    • 58249096063 scopus 로고    scopus 로고
    • Cellulose microfibrils from banana rachis: Effect of alkaline treatments on structural and morphological features
    • R. Zuluaga, J. L. Putaux, J. Cruz, J. Vélez, I. Mondragon and P. Gan?án: 'Cellulose microfibrils from banana rachis: effect of alkaline treatments on structural and morphological features', Carbohydr. Polym., 2009, 76, (1), 51-59.
    • (2009) Carbohydr. Polym. , vol.76 , Issue.1 , pp. 51-59
    • Zuluaga, R.1    Putaux, J.L.2    Cruz, J.3    Vélez, J.4    Mondragon, I.5    Ganán, P.6
  • 32
    • 37549056891 scopus 로고    scopus 로고
    • Isolation and characterization of nanofibers from agricultural residues-wheat straw and soy hulls
    • A. Alemdar and M. Sain: 'Isolation and characterization of nanofibers from agricultural residues-wheat straw and soy hulls', Bioresour. Technol., 2008, 99, (6), 1664-1671.
    • (2008) Bioresour. Technol. , vol.99 , Issue.6 , pp. 1664-1671
    • Alemdar, A.1    Sain, M.2
  • 33
    • 84857129265 scopus 로고    scopus 로고
    • Extraction, preparation and characterization of cellulose fibres and nanocrystals from rice husk
    • N. Johar, I. Ahmad and A. Dufresne: 'Extraction, preparation and characterization of cellulose fibres and nanocrystals from rice husk', Ind. Crops Prod., 2012, 37, (1), 93-99.
    • (2012) Ind. Crops Prod. , vol.37 , Issue.1 , pp. 93-99
    • Johar, N.1    Ahmad, I.2    Dufresne, A.3
  • 34
    • 33750549274 scopus 로고    scopus 로고
    • Dilute solution properties of cellulose in LiOH/urea aqueous system
    • J. Cai, Y. Liu and L. Zhang: 'Dilute solution properties of cellulose in LiOH/urea aqueous system', J. Polym. Sci. B, 2006, 44B, (21), 3093-3101.
    • (2006) J. Polym. Sci. B , vol.44 B , Issue.21 , pp. 3093-3101
    • Cai, J.1    Liu, Y.2    Zhang, L.3
  • 35
    • 84863281793 scopus 로고    scopus 로고
    • Comparison of dynamic adsorption/desorption characteristics of toluene on different porous materials
    • W. Zhang, Z. Qu, X. Li, Y. Wang, D. Ma and J. Wu: 'Comparison of dynamic adsorption/desorption characteristics of toluene on different porous materials', J. Environ. Sci., 2012, 24, (3), 520-528.
    • (2012) J. Environ. Sci. , vol.24 , Issue.3 , pp. 520-528
    • Zhang, W.1    Qu, Z.2    Li, X.3    Wang, Y.4    Ma, D.5    Wu, J.6
  • 36
    • 25444448841 scopus 로고    scopus 로고
    • Crystalline structure analysis of cellulose treated with sodium hydroxide and carbon dioxide by means of X-ray diffraction and FTIR spectroscopy
    • S. Y. Oh, D. I. Yoo, Y. Shin, H. C. Kim, H. Y. Kim, Y. S. Chung, W. H. Park and J. H. Youk: 'Crystalline structure analysis of cellulose treated with sodium hydroxide and carbon dioxide by means of X-ray diffraction and FTIR spectroscopy', Carbohydr. Res., 2005, 340, (15), 2376-2391.
    • (2005) Carbohydr. Res. , vol.340 , Issue.15 , pp. 2376-2391
    • Oh, S.Y.1    Yoo, D.I.2    Shin, Y.3    Kim, H.C.4    Kim, H.Y.5    Chung, Y.S.6    Park, W.H.7    Youk, J.H.8
  • 37
    • 84874943365 scopus 로고    scopus 로고
    • Polymorphic transformation of cellulose i to cellulose II by alkali pretreatment and urea as an additive
    • P. K. Gupta, V. Uniyal and S. Naithani: 'Polymorphic transformation of cellulose I to cellulose II by alkali pretreatment and urea as an additive', Carbohydr. Polym., 2013, 94, (2), 843-849.
    • (2013) Carbohydr. Polym. , vol.94 , Issue.2 , pp. 843-849
    • Gupta, P.K.1    Uniyal, V.2    Naithani, S.3
  • 38
    • 79953898776 scopus 로고    scopus 로고
    • Transition of cellulose crystalline structure and surface morphology of biomass as a function of ionic liquid pretreatment and its relation to enzymatic hydrolysis
    • G. Cheng, P. Varanasi, C. Li, H. Liu, Y. B. Melnichenko, B. A. Simmons, M. S. Kent and S. Singh: 'Transition of cellulose crystalline structure and surface morphology of biomass as a function of ionic liquid pretreatment and its relation to enzymatic hydrolysis', Biomacromolecules, 2011, 12, (4), 933-941
    • (2011) Biomacromolecules , vol.12 , Issue.4 , pp. 933-941
    • Cheng, G.1    Varanasi, P.2    Li, C.3    Liu, H.4    Melnichenko, Y.B.5    Simmons, B.A.6    Kent, M.S.7    Singh, S.8
  • 39
    • 37849027059 scopus 로고    scopus 로고
    • Effect of enzymatic treatment on cotton fiber dissolution in NaOH/urea solution at cold temperature
    • Y. Wang, Y. Zhao and Y. Deng: 'Effect of enzymatic treatment on cotton fiber dissolution in NaOH/urea solution at cold temperature', Carbohydr. Polym., 2008, 72, (1), 178-184.
    • (2008) Carbohydr. Polym. , vol.72 , Issue.1 , pp. 178-184
    • Wang, Y.1    Zhao, Y.2    Deng, Y.3
  • 40
    • 82055185546 scopus 로고    scopus 로고
    • Morphological and crystalline characterization of NaOH and NaOCl treated Agave americana L. Fiber
    • A. E. O. Ben Sghaier, Y. Chaabouni, S. Msahli and F. Sakli: 'Morphological and crystalline characterization of NaOH and NaOCl treated Agave americana L. fiber', Ind. Crops Prod., 2012, 36, (1), 257-266.
    • (2012) Ind. Crops Prod. , vol.36 , Issue.1 , pp. 257-266
    • Ben Sghaier, A.E.O.1    Chaabouni, Y.2    Msahli, S.3    Sakli, F.4
  • 41
    • 34248638164 scopus 로고    scopus 로고
    • Characteristics of hemicellulose, cellulose and lignin pyrolysis
    • H. Yang, R. Yan, H. Chen, D. H. Lee and C. Zheng: 'Characteristics of hemicellulose, cellulose and lignin pyrolysis', Fuel, 2007, 86, (12-13), 1781-1788.
    • (2007) Fuel , vol.86 , Issue.12-13 , pp. 1781-1788
    • Yang, H.1    Yan, R.2    Chen, H.3    Lee, D.H.4    Zheng, C.5
  • 42
    • 0033078224 scopus 로고    scopus 로고
    • Pyrolysis kinetics of lignocellulosic materials-three independent reactions model
    • J. J. M. Orfa?o, F. J. A. Antunes and J. L. Figueiredo: 'Pyrolysis kinetics of lignocellulosic materials-three independent reactions model', Fuel, 1999, 78, (3), 349-358.
    • (1999) Fuel , vol.78 , Issue.3 , pp. 349-358
    • Orfao, J.J.M.1    Antunes, F.J.A.2    Figueiredo, J.L.3
  • 43
    • 84882950790 scopus 로고    scopus 로고
    • Approaching super-hydrophobicity from cellulosic materials: A Review
    • J. Song and O. J. Rojas: 'Approaching super-hydrophobicity from cellulosic materials: A Review', Nord. Pulp Pap. Res. J, 2013, 28, 216-238.
    • (2013) Nord. Pulp Pap. Res. J , vol.28 , pp. 216-238
    • Song, J.1    Rojas, O.J.2
  • 44
    • 0242386553 scopus 로고    scopus 로고
    • Uniform mesopore-donated zeolite y using carbon aerogel templating
    • J Y. Tao, H. Kanoh and K. Kaneko: 'Uniform mesopore-donated zeolite Y using carbon aerogel templating', J. Phys. Chem. B, 2003, 107B, (40), 10974-10976.
    • (2003) J. Phys. Chem. B , vol.107 B , Issue.40 , pp. 10974-10976
    • Tao, J.Y.1    Kanoh, H.2    Kaneko, K.3


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