Peristaltic pumping under poroelastic confinement
Pith reviewed 2026-05-10 19:56 UTC · model grok-4.3
The pith
Poroelastic confinement inhibits peristaltic pumping by raising viscous dissipation at the interface and requiring energy to deform the solid.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Peristaltic flow through the channel is inhibited by poroelastic confinement owing to increased viscous dissipation across the interface and energy loss in deforming the elastic solid. Permeability and slip interact with the material stiffness to produce material-dependent regimes of forward or backward interstitial flow within the poroelastic domain. The maximum Darcy flow occurs at permeability values that optimize the elastic-matrix interaction.
What carries the argument
Asymptotic expansion in peristaltic amplitude that solves the coupled Stokes flow and linear poroelastic deformation, with the solution depending nonlinearly on stiffness, permeability, and slip.
If this is right
- Net forward flow in the channel decreases as poroelastic stiffness drops or as permeability rises beyond the optimal value.
- Interstitial flow inside the poroelastic solid reverses direction when permeability and slip cross thresholds set by the stiffness.
- Maximum interstitial Darcy velocity occurs at a permeability that balances viscous drag through the pores against elastic resistance to deformation.
- Interfacial slip modulates both the channel flow reduction and the location of the permeability optimum.
Where Pith is reading between the lines
- Biological conduits bounded by soft porous tissue may exhibit flow regulation or reversal simply by changing local tissue permeability without altering wave amplitude.
- Microfluidic pumps with soft porous ceilings could be designed so that a single permeability value simultaneously maximizes both channel throughput and interstitial transport.
- The model implies that slip length at the fluid-solid interface is an independent control parameter that can be tuned to shift the permeability optimum without changing bulk material properties.
Load-bearing premise
The peristaltic amplitude is small enough for the asymptotic expansion to remain valid and the poroelastic half-space obeys standard linear constitutive relations without nonlinear effects or boundary-layer corrections.
What would settle it
Measure net channel flow rate and interstitial Darcy velocity while holding stiffness fixed and varying permeability across several orders of magnitude; the data should show a clear peak in Darcy velocity at an intermediate permeability rather than monotonic increase or decrease.
Figures
read the original abstract
Low Reynolds number flow near a poroelastic interface can be found across scales in biological and engineered systems. We develop a 2D model of peristaltic flow confined under a poroelastic solid. In this geometry, the lower boundary is an infinite train of traveling waves which pump fluid along a channel. The upper boundary of the flow is a poroelastic half space. The flow and deformation are solved analytically by an asymptotic expansion in the peristaltic amplitude and depend nonlinearly on dimensionless poroelastic stiffness, permeability, and interfacial slip. We quantify the effect of material properties on the poroelastic fluid-structure interaction. Peristaltic flow through the channel is inhibited by poroelastic confinement owing to increased viscous dissipation across the interface and energy loss in deforming the elastic solid. Permeability and slip interact with the material stiffness to produce material dependent regimes of forward or backward interstitial flow within the poroelastic domain. The maximum Darcy flow is found to occur at permeability values that optimize the elastic matrix interaction.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript develops a two-dimensional model of peristaltic flow in a channel bounded below by a traveling wave and above by a poroelastic half-space. The flow and solid deformation are solved using an asymptotic expansion in the small peristaltic amplitude, yielding analytical expressions that depend nonlinearly on the dimensionless poroelastic stiffness, permeability, and interfacial slip. The authors conclude that poroelastic confinement inhibits the net peristaltic pumping through increased viscous dissipation at the interface and energy dissipation associated with deforming the elastic solid. Additionally, the interaction of permeability and slip with stiffness produces regimes of forward or backward interstitial Darcy flow in the poroelastic domain, with the maximum Darcy flow occurring at permeability values that optimize the elastic matrix interaction.
Significance. If the asymptotic results hold, this work provides an analytical characterization of fluid-poroelastic interactions in low-Re peristaltic systems relevant to biological and microfluidic applications. The derivation of material-dependent flow regimes and an optimal permeability for maximum interstitial flow offers concrete, testable predictions. The parameter-free analytical approach is a strength, enabling clear delineation of the roles of stiffness, permeability, and slip without reliance on fitted data.
major comments (2)
- [Abstract and asymptotic analysis] The central claims of flow inhibition and material-dependent forward/backward interstitial flow regimes rest on the validity of the small-amplitude asymptotic expansion together with linear poroelastic constitutive relations. The abstract provides no indication that the expansion was validated against numerical solutions of the full nonlinear problem or that higher-order geometric nonlinearities at the deforming interface were quantified. If O(ε²) corrections reverse the sign of the Darcy flow or shift the permeability optimum, the reported regimes would not hold. Explicit error estimates or comparisons are required to support the conclusions.
- [Results on Darcy flow] The statement that the maximum Darcy flow occurs at permeability values optimizing the elastic matrix interaction is load-bearing for the material-dependent regimes claim. The manuscript should include the explicit leading-order expressions for net pumping rate and Darcy velocity (as functions of the dimensionless groups) together with supporting plots or tables that locate and quantify this optimum.
minor comments (1)
- [Abstract] The abstract would be clearer if it briefly defined the key dimensionless groups (stiffness, permeability, slip) and indicated the parameter ranges over which the regimes are observed.
Simulated Author's Rebuttal
We thank the referee for the careful and constructive review, which highlights both the strengths of the analytical approach and areas where clarity can be improved. We address each major comment below and will revise the manuscript to incorporate the suggestions.
read point-by-point responses
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Referee: [Abstract and asymptotic analysis] The central claims of flow inhibition and material-dependent forward/backward interstitial flow regimes rest on the validity of the small-amplitude asymptotic expansion together with linear poroelastic constitutive relations. The abstract provides no indication that the expansion was validated against numerical solutions of the full nonlinear problem or that higher-order geometric nonlinearities at the deforming interface were quantified. If O(ε²) corrections reverse the sign of the Darcy flow or shift the permeability optimum, the reported regimes would not hold. Explicit error estimates or comparisons are required to support the conclusions.
Authors: We agree that the range of validity of the asymptotic expansion merits explicit discussion. The analysis uses a regular perturbation expansion to O(ε) with linearized boundary conditions at the mean interface position, following the standard approach for small-amplitude peristaltic pumping. The leading-order Darcy velocity and net pumping rate are therefore the dominant terms for ε ≪ 1; O(ε²) corrections enter as relative perturbations of size O(ε) and are not expected to reverse signs or relocate the permeability optimum within the stated regime. In the revision we will (i) add a dedicated paragraph in the methods or discussion section providing order-of-magnitude estimates for the neglected nonlinear terms, (ii) state the assumed range ε < 0.2 explicitly in the abstract and introduction, and (iii) clarify that full nonlinear numerical validation lies beyond the present analytical scope but is a natural direction for future work. revision: partial
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Referee: [Results on Darcy flow] The statement that the maximum Darcy flow occurs at permeability values optimizing the elastic matrix interaction is load-bearing for the material-dependent regimes claim. The manuscript should include the explicit leading-order expressions for net pumping rate and Darcy velocity (as functions of the dimensionless groups) together with supporting plots or tables that locate and quantify this optimum.
Authors: We thank the referee for this helpful suggestion. The leading-order expressions for the net channel pumping rate Q and the interstitial Darcy velocity u_D are already derived analytically in Sections 3 and 4 as explicit functions of the three dimensionless groups (stiffness K̂, permeability κ̂, and slip λ̂); the optimum permeability is obtained by setting ∂u_D/∂κ̂ = 0 at fixed K̂ and λ̂. In the revised manuscript we will (i) collect these closed-form expressions in a new table or appendix for easy reference, (ii) add a figure that plots u_D versus κ̂ for representative values of K̂ and λ̂, and (iii) annotate the location and magnitude of the maximum on the plot together with the corresponding analytic condition. revision: yes
Circularity Check
No circularity: standard asymptotic expansion on linear equations yields independent results
full rationale
The derivation applies a small-amplitude asymptotic expansion to the standard low-Re Stokes equations coupled to linear poroelastic constitutive relations. The resulting analytic expressions for channel flow inhibition, interstitial Darcy regimes, and optimal permeability are obtained by solving the linearized boundary-value problem; they are not obtained by fitting parameters to the target quantities, by self-definition, or by load-bearing self-citation. The dependence on stiffness, permeability, and slip emerges from the solution rather than being presupposed. No step reduces the claimed predictions to the inputs by construction.
Axiom & Free-Parameter Ledger
axioms (3)
- domain assumption Low Reynolds number flow approximation
- domain assumption Linear poroelastic constitutive relations for the solid
- domain assumption No-slip or partial-slip interface conditions
Lean theorems connected to this paper
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IndisputableMonolith/Cost/FunctionalEquation.leanwashburn_uniqueness_aczel unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
The flow and deformation are solved analytically by an asymptotic expansion in the peristaltic amplitude and depend nonlinearly on dimensionless poroelastic stiffness, permeability, and interfacial slip.
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IndisputableMonolith/Foundation/AbsoluteFloorClosure.leanabsolute_floor_iff_bare_distinguishability unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
We use a BJS condition that includes solid deformation velocity in the interfacial velocity jump
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
-
[1]
A. H. Shapiro, M. Y. Jaffrin, and S. L. Weinberg, Peristaltic pumping with long wavelengths at low Reynolds number, J. Fluid Mech.37, 799 (1969)
work page 1969
-
[2]
J. M. Floryan, S. Panday, and K. M. Faisal, On the peristaltic pumping, Phys. Fluids33, 033609 (2021)
work page 2021
-
[3]
M. Y. Jaffrin and A. H. Shapiro, Peristaltic pumping, Annu. Rev. Fluid Mech.3, 13 (1971)
work page 1971
-
[4]
Y. C. Fung and C. S. Yih, Peristaltic transport, J. Appl. Mech.35, 669 (1968)
work page 1968
-
[5]
A. M. Provost and W. H. Schwarz, A theoretical study of viscous effects in peristaltic pumping, J. Fluid Mech.279, 177 (1994). 19
work page 1994
-
[6]
D. Takagi and N. J. Balmforth, Peristaltic pumping of viscous fluid in an elastic tube, J. Fluid Mech.672, 196 (2011)
work page 2011
-
[7]
K. P. Selverov and H. A. Stone, Peristaltically driven channel flows with applications toward micromixing, Phys. Fluids13, 1837 (2001)
work page 2001
-
[8]
F. Forouzandeh, A. Arevalo, A. Alfadhel, and D. A. Borkholder, A review of peristaltic mi- cropumps, Sens. Actuators A Phys.326, 112602 (2021)
work page 2021
-
[9]
F. Roman` o, V. Suresh, P. A. Galie, and J. B. Grotberg, Peristaltic flow in the glymphatic system, Sci. Rep.10, 21065 (2020)
work page 2020
-
[10]
F. K. B¨ auerle, S. Karpitschka, and K. Alim, Living System Adapts Harmonics of Peristaltic Wave for Cost-Efficient Optimization of Pumping Performance, Phys. Rev. Lett.124, 098102 (2020)
work page 2020
-
[11]
P. Hadaczek, Y. Yamashita, H. Mirek, L. Tamas, M. C. Bohn, C. Noble, J. W. Park, and K. Bankiewicz, The “perivascular pump” driven by arterial pulsation is a powerful mechanism for the distribution of therapeutic molecules within the brain, Mol. Ther.14, 69 (2006)
work page 2006
-
[12]
P. Wang and W. L. Olbricht, Fluid mechanics in the perivascular space, J. Theor. Biol.274, 52 (2011)
work page 2011
- [13]
-
[14]
A. Trevino, T. R. Powers, R. Zenit, and M. Rodriguez Jr, Low reynolds number pumping near an elastic half space, Phys. Rev. Fluids10, 054003 (2025)
work page 2025
-
[15]
N. N. Haq and J. M. Floryan, Propulsive effect of wall vibrations, J. Fluids Eng.144, 121204 (2022)
work page 2022
-
[16]
S. L. Weinberg, E. C. Eckstein, and A. H. Shapiro, An experimental study of peristaltic pumping, J. Fluid Mech.49, 461 (1971)
work page 1971
-
[17]
J. H. Thomas, Fluid dynamics of cerebrospinal fluid flow in perivascular spaces, J. R. Soc. Interface16(2019)
work page 2019
-
[18]
N. Yokoyama, N. Takeishi, and S. Wada, Cerebrospinal fluid flow driven by arterial pulsations in axisymmetric perivascular spaces: Analogy with Taylor’s swimming sheet, J. Theor. Biol. 523, 110709 (2021). 20
work page 2021
-
[19]
G. I. Taylor, Analysis of the swimming of microscopic organisms, Proc. R. Soc. London A 209, 447 (1951)
work page 1951
-
[20]
D. F. Katz, On the propulsion of micro-organisms near solid boundaries, J. Fluid Mech.64, 33 (1974)
work page 1974
-
[21]
M. A. Dias and T. R. Powers, Swimming near deformable membranes at low Reynolds number, Phys. Fluids25, 101901 (2013)
work page 2013
-
[22]
V. A. Shaik and A. M. Ardekani, Swimming sheet near a plane surfactant-laden interface, Phys. Rev. E99(2019)
work page 2019
-
[23]
D. Hewitt and N. Balmforth, Taylor’s swimming sheet in a yield-stress fluid, J. Fluid Mech. 828, 33 (2017)
work page 2017
-
[24]
A. Jha, Y. Amarouchene, and T. Salez, Taylor’s swimming sheet near a soft boundary, Soft Matter21, 826 (2025)
work page 2025
-
[25]
A. J. Reynolds, The swimming of minute organisms, J. Fluid Mech.23, 241 (1965)
work page 1965
- [26]
-
[27]
A. M. Leshansky, Enhanced low-Reynolds-number propulsion in heterogeneous viscous envi- ronments, Phys. Rev. E80, 051911 (2009)
work page 2009
-
[28]
J. R. Blake, Infinite models for ciliary propulsion, J. Fluid Mech.49, 209 (1971)
work page 1971
-
[29]
H. C. Fu, V. B. Shenoy, and T. R. Powers, Low-Reynolds-number swimming in gels, EPL91, 24002 (2010)
work page 2010
- [30]
-
[31]
J. Tchoufag, P. Ghosh, C. B. Pogue, B. Nan, and K. K. Mandadapu, Mechanisms for bacterial gliding motility on soft substrates, Proc. Natl. Acad. Sci. U.S.A.116, 25087 (2019)
work page 2019
- [32]
-
[33]
A. Zilberman and R. C. Cornelison, Microphysiological models of the central nervous system with fluid flow, Brain Research Bulletin174, 72 (2021)
work page 2021
-
[34]
V. A. Shaik and A. M. Ardekani, Motion of a model swimmer near a weakly deforming interface, J. Fluid Mech.824, 42 (2017). 21
work page 2017
-
[35]
A. Winn and E. Katifori, Geometry of contraction-induced flows, Phys. Rev. Fluids11, 033101 (2026)
work page 2026
-
[36]
D. H. Kelley, Brain cerebrospinal fluid flow, Phys. Rev. Fluids6, 070501 (2021)
work page 2021
-
[37]
A. Mudugamuwa, U. Roshan, S. Hettiarachchi, H. Cha, H. Musharaf, X. Kang, Q. T. Trinh, H. M. Xia, N.-T. Nguyen, and J. Zhang, Periodic flows in microfluidics, Small20, 2404685 (2024)
work page 2024
-
[38]
H. J. Kim, D. Huh, G. Hamilton, and D. E. Ingber, Human gut-on-a-chip inhabited by mi- crobial flora that experiences intestinal peristalsis-like motions and flow, Lab Chip12, 2165 (2012)
work page 2012
-
[39]
D. Huh, B. D. Matthews, A. Mammoto, M. Montoya-Zavala, H. Y. Hsin, and D. E. Ingber, Reconstituting organ-level lung functions on a chip, Science328, 1662 (2010)
work page 2010
-
[40]
E. Moeendarbary, L. Valon, M. Fritzsche, A. R. Harris, D. A. Moulding, A. J. Thrasher, E. Stride, L. Mahadevan, and G. T. Charras, The cytoplasm of living cells behaves as a poroelastic material, Nature materials12, 253 (2013)
work page 2013
-
[41]
G. Franceschini, D. Bigoni, P. Regitnig, and G. A. Holzapfel, Brain tissue deforms similarly to filled elastomers and follows consolidation theory, Journal of the Mechanics and Physics of Solids54, 2592 (2006)
work page 2006
-
[42]
W. M. Lai, J. S. Hou, and V. C. Mow, A triphasic theory for the swelling and deformation behaviors of articular cartilage, Journal of Biomechanical Engineering113, 245 (1991)
work page 1991
-
[43]
M. A. Swartz and M. E. Fleury, Interstitial flow and its effects in soft tissues, Annu. Rev. Biomed. Eng.9, 229 (2007)
work page 2007
-
[44]
S. Maiti and J. Misra, Peristaltic flow of a fluid in a porous channel: a study having relevance to flow of bile within ducts in a pathological state, Int. J. Eng. Sci.49, 950 (2011)
work page 2011
-
[45]
V. C. Mow, S. Kuei, W. M. Lai, and C. G. Armstrong, Biphasic creep and stress relaxation of articular cartilage in compression: theory and experiments, J. Biomech. Eng.102, 73 (1980)
work page 1980
-
[46]
A. Koroleva, A. Deiwick, A. Nguyen, R. Narayan, A. Shpichka, O. Kufelt, R. Kiyan, V. Bagratashvili, P. Timashev, T. Scheper,et al., Hydrogel-based microfluidics for vascular tissue engineering, BioNanoMaterials17, 19 (2016)
work page 2016
-
[47]
Darcy,Les Fontaines Publiques de la Ville de Dijon(Victor Dalmont, Paris, 1856)
H. Darcy,Les Fontaines Publiques de la Ville de Dijon(Victor Dalmont, Paris, 1856)
-
[48]
M. A. Biot, General theory of three-dimensional consolidation, J. Appl. Phys.12, 155 (1941). 22
work page 1941
- [49]
-
[50]
V. M. Yarushina, D. Bercovici, and M. L. Oristaglio, Rock deformation models and fluid leak-off in hydraulic fracturing, Geophysical Journal International194, 1514 (2013)
work page 2013
-
[51]
J. Rutqvist, The geomechanics of co2 storage in deep sedimentary formations, Geotechnical and Geological Engineering30, 525 (2012)
work page 2012
-
[52]
J. Bear and M. Y. Corapcioglu, Mathematical model for regional land subsidence due to pumping: 2. integrated aquifer subsidence equations for vertical and horizontal displacements, Water Resources Research17, 947 (1981)
work page 1981
-
[53]
Whitaker, Flow in porous media I: A theoretical derivation of Darcy’s law, Transp
S. Whitaker, Flow in porous media I: A theoretical derivation of Darcy’s law, Transp. Porous Med.1, 3 (1986)
work page 1986
-
[54]
H. C. Brinkman, A calculation of the viscous force exerted by a flowing fluid on a dense swarm of particles, Flow Turbul. Combust.1, 27 (1949)
work page 1949
- [55]
-
[56]
R. Ruiz-Baier, M. Taffetani, H. D. Westermeyer, and I. Yotov, The Biot–Stokes coupling using total pressure: formulation, analysis and application to interfacial flow in the eye, Comput. Methods Appl. Mech. Eng.389, 114384 (2022)
work page 2022
-
[57]
S. M. Finney, M. G Hennessy, A. M¨ unch, and S. L. Waters, The impact of confinement on the deformation of an elastic particle under axisymmetric tube flow, IMA J. Appl. Math.89, 498 (2024)
work page 2024
-
[58]
S. M. Finney, M. G. Hennessy, A. M¨ unch, and S. L. Waters, Weakly deformable poroelastic particle in an unbounded stokes flow, Phys. Rev. Fluids10(2025)
work page 2025
-
[59]
G. S. Beavers and D. D. Joseph, Boundary conditions at a naturally permeable wall, J. Fluid Mech.30, 197 (1967)
work page 1967
-
[60]
P. G. Saffman, On the boundary condition at the surface of a porous medium, Stud. Appl. Math.50, 93 (1971)
work page 1971
-
[61]
J. A. Ochoa-Tapia and S. Whitaker, Momentum transfer at the boundary between a porous medium and a homogeneous fluid—I. Theoretical development, Int. J. Heat Mass Transfer38, 2635 (1995). 23
work page 1995
-
[62]
Minale, Momentum transfer within a porous medium
M. Minale, Momentum transfer within a porous medium. I. Theoretical derivation of the momentum balance on the solid skeleton, Phys. Fluids26, 123101 (2014)
work page 2014
-
[63]
J. J. Feng and Y.-N. Young, Boundary conditions at a gel-fluid interface, Phys. Rev. Fluids 5, 124304 (2020)
work page 2020
-
[64]
Z. Xu, J. Zhang, Y.-N. Young, P. Yue, and J. J. Feng, Comparison of four boundary conditions for the fluid-hydrogel interface, Phys. Rev. Fluids7, 093301 (2022)
work page 2022
-
[65]
P. G. Saffman, On the Boundary Condition at the Surface of a Porous Medium, Stud. Appl. Math.50, 93 (1971)
work page 1971
-
[66]
Lighthill, Acoustic streaming in the ear itself, J
J. Lighthill, Acoustic streaming in the ear itself, J. Fluid Mech.239, 551 (1992)
work page 1992
-
[67]
D. G. Andrews and M. E. Mcintyre, An exact theory of nonlinear waves on a Lagrangian-mean flow, J. Fluid Mech.89, 609 (1978)
work page 1978
- [68]
-
[69]
K. Kalayeh, H. Xie, J. B. Fowlkes, B. S. Sack, and W. W. Schultz, Longitudinal wall motion during peristalsis and its effect on reflux, J. Fluid Mech.964, 799 (2023)
work page 2023
-
[70]
H. Y. Kwon, C. Streilein, and R. C. Cornelison, Convective forces contribute to post-traumatic degeneration after spinal cord injury, Bioengineering & Translational Medicine10, e10739 (2025)
work page 2025
-
[71]
F. Habel and A. C. Bagtzoglou, Wave induced flow and transport in sediment beds, J. Am. Water Resour. Assoc.41, 461 (2005)
work page 2005
-
[72]
J. J. Webber and H. E. Huppert, Stokes drift through corals, Environ. Fluid Mech.21, 1119 (2021)
work page 2021
-
[73]
J. E. H. Weber and P. Ghaffari, Wave-induced Lagrangian drift in a porous seabed, Environ. Fluid Mech.23, 191 (2023)
work page 2023
-
[74]
M. G. Trefry, D. R. Lester, G. Metcalfe, and J. Wu, Temporal fluctuations and poroelasticity can generate chaotic advection in natural groundwater systems, Water Resour. Res.55, 3347 (2019)
work page 2019
-
[75]
C. Meza-Valle and N. Pujara, Flow in oscillatory boundary layers over permeable beds, Phys. Fluids34(2022)
work page 2022
-
[76]
Y. Gan, Y. Guo, J. H. Thomas, K. A. Boster, J. K. Shang, and D. H. Kelley, Antidispersion in flows in leaky channels, Physical Review Letters135, 204001 (2025). 24
work page 2025
-
[77]
J. A. Ochoa-Tapia and S. Whitaker, Momentum transfer at the boundary between a porous medium and a homogeneous fluid—II. Comparison with experiment, Int. J. Heat Mass Transfer 38, 2647 (1995)
work page 1995
-
[78]
Minale, Momentum transfer within a porous medium
M. Minale, Momentum transfer within a porous medium. II. Stress boundary condition, Phys. Fluids26, 123102 (2014). 25
work page 2014
discussion (0)
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