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IJAO

ISSN 0391-3988 ORIGINAL ARTICLE

as an a art a s t t r na a -r an f-r fr anti ag ant t ra (1) As s gg st

t t rat r (2 3) tiss a s a a arg r ntra r t an an a a s an r s t n t r -ti n f t r n s arg r r a s r s na n ti ns an a s a r as n trans a -ar r ss r r s A t s nts an a t r as tra a r s t t s r a s f arti a art a s n t r s n r s ar fr fr ati ns f r r s g t r nt str ss s at t a ti a-ti n n ar tis t r nts ar s ng fr t f r ati n an t r s s nt ta nt On t t r an r st ti art a s s r fr str t ra a -ar t r rati n a t a ati n an r t ar ng an s rt t r ra t (1) r art a s ( s) r n r r t n t ra t f t s t t ati -t f -t s rst - a t r st ti art a s r ant n t 1960s t a t g s nt ti art a s t a ta s rt-t r an a r rti s OI: 10 5301 a 5000 52

Fluid dynamic characterization of a polymeric heart

valve prototype (Poli-Valve) tested under continuous

and pulsatile flow conditions

Francesco De Gaetano1, Marta Serrani2, Paola Bagnoli1, Jacob Brubert2, Joanna Stasiak2, Geoff D. Moggridge2,

Maria Laura Costantino1

1 art nt f str at r a s an a ng n r ng Na a t n an an - Ita 2 art nt f a ng n r ng an t n g n rs t f a r g a r g -

Introduction

N a a s 2 a r t s f anta arti a art a s ar a a a : an a an r st ti art a s A t g an a art a s ( s) a n t st n ant s n t ast ars t an s t t r r a ng t r ra t r st ti tis-s art a tis-s ( s) ar rr nt ant as fr nt ABStrACt Purpose: On an a an g a art a r st s s ar rr nt r a a a a f r r s ng r ra t t r r anti ag ant t ra ; t a r s a r na a r t n t a a at ra t N r art a s ( s) t ntia n t na r rti s f g a a s t t ra t f an a a s s r r s nts a r na a -ati n f 2 gr s f n s ra-ann ar tr a t r st ti art a s a fr st r n

rs (S ): - a s

Methods: 2 t s f - a s a f S an r ng n st r n fra ti n nt nt r t st n r ntin s an sati n ti ns as r s r ISO 58 0 Stan ar A s at r s gn a a t a r t t s t t st at r nt rat s an fr n s r ss r an r r r ; r ss r r s ti r ar a ( OA) an r g rg tant r t t ass ss t

-a r f t -a

results: t t s f - a s t t n r r nts n t r s f r g rg tati n an OA as s t ISO 58 0 Stan ar s ts r ar t 5 an a art a s ( s) an 5 tiss art a s ( s) rr nt a a a n t ar t

Conclusions: as n t s r s ts s as n st r n rs as ar a s an ns -r a -r s ng a t rnati f r art a r a nt n t n ar f t r

Keywords: art a r st s s r art a s s at r sati St r n

-rs

Accepted: r 1 2015 Published online: r 1 2015 Corresponding author:

Francesco De Gaetano

Laboratory of Biological Structure Mechanics Department of Chemistry

Materials and Chemical Engineering Giulio Natta Politecnico di Milano

Piazza Leonardo da Vinci 32 20133 Milan, Italy

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t r s s ti t t r ti an ati gra ati n an s s nt an a fa r a t t r s ss-f s ( 5)

In r nt ars a an s n r s n a g n r s t an rtant n ass f arti a art a r

-nant a f r t an - as at r a s s g ati t an sta t (6-9) a gra s g nt r t an ( ) as n s ssf a n ar s ar as ar s a s ar r-r nt ti s n r a a a a ass st s (10 11) t n r r st s s a r n ng-t r ra t f r n a antati n s far t t r ti gra ati n f t r t an a n n r in vivo n -ti ns (12) r r nt t nt n r at r a t n g s a n nan s t r ati n as ra s nt r st aga n n f r art a s an t a (13) r s nan - r t an s as nn a-ti sta at r a s a a f r ng t - n n

gra ati n ss f r stan ar t a f n ti n-a n-ati n f ts ati r s a s t ( ar nat - r a)

s g nt n t ra g r s s s -an s n-an arti s (1 15) An a t rnati n f r s ta f r t s gn f s nt ti art a r st s s s r nan -s t -s str t r f rs an ta r t a an a an a a r rti s starting fr t n f 2 r r rs r rti s f t na r t t n t s f t n tia at r a s (16) A ng t ss n s n ast rs as n st r n r a ng r s as a a a rs f r t nstr ti n f art a r st s s t t r g ati t r s ng an a r r-ti s an ati n r s stan (1 -20) In r a a a a rs s as (St r n -Is t n -St r n ) (SI S; Inn a rs) s s r r -a st-a t (21 22) -an g fatig r s ns (23 2 ) n an ng-t r ra t t r g n t an na a r ang t a (25) r n-f r nt t n t r t a at ( ) fa r nt (st r n - - s t n - -st r n ) (SI S) an t s rfa f t s r st ti a s t a -r st s ati n ( ) at s SI S a s fa n an a t sting a s f at r a a ag an a ati n a t s ra a s t r rti s f SI S a t r n r r t r t str t ra nt gr t r r f r ng-t r s in vivo t s r s Stas a t a (26) s t r an a tr at nts t ang t r str t r f st r n rs an ns nt t r an a a r In arti ar nstrat t at a n r a r -g f t r a ns a t rn fr s tr t r nt r ss n ng n ann s (20) s an s tr r r g f ti t str t r -f n ti n -f an s tr ag n n t nati a r ng t rf r an f t (2 ) a f t s r s t ara t r t r na a r f n r t t s ( - a ) fa r at a r ss n ng n r ntin s an sati n -ti ns n r r t st t a a f t - a t

s as an a t rnati t an a an tiss art a s rr nt n t ar t Methods A t ta f 16 n r t t s ( - a s) r an-fa t r r ss n ng t n fr t f-f r nt r a a a a st r n rs (S ) ta n fr rat n rf r an rs gr s f a s r n stigat a n r s ng 8 a s: r A: a s an fa t r fr (st r n b s -r n ta n -b-st r n ) rs t 19

r ntag ass ( t) st r n fra t n

r : a s an fa t r fr (st r n b s -r n -b-st -r n ) rs t 30 t -st r n fra t n t at r a s ar n ar rs t narr -ar g t str ti n f a t 180 g -1 an 130 g -1 f r gr s A an r s ti r nt st -r n f-ra ti n t at a-ra t -r s t 2 at -r a s s -r s n-s f r a r nt sti n ss f t s rs sti n ss s r t r at t t r an a str ngt as r rt n (19) nts ( g 1A) r an fa t r n a -n s ar r s n ( a r g a t r s gn) as n a 3- ns na g tr r ating t nat ra n g ra-ti n f tr a t art a s (28) - a r t t s r ta n t r ss ng at 150 s (a r at 0 5 3) f t r n tia at at t -ss ra f a f t 3 a ts f t a - a g tr r an ns ns ar r rt n g r s 1 an - a s ng ng t t r A an r r t st in vitro n r ntin s an sati t a at r ss r r s an r g rg tati n n t n ti ns as r n ISO 58 0 Stan ar (29) ntin s an sati t sts r rf r s ng sti at r at r t rat r (25 ) Continuous tests r nta t st n s t a at - a r ss r r s n ntin s n ti ns s s n n g r 2A s t ns st f a r s r r a ntr f ga ( IO- I S - 550 IO ONSO ; tr n ) an a a s ng n t ( ) s gn a r ng t t g -n s f t ISO 58 0 Sta-n ar a s r s a t O-r ngs n t t a an a ag a s r t st at rat s rang ng fr 0 t 10 n t an n r nta st f 0 5 n rans a -ar r ss r r as as r 3 ti s f r a a r ss r trans rs (1 0 r ss r s ns rs n ) t r f t r ata t f t t sts r nta s t f r t r g rg tati n t st -r s a a (t sa s r ng t ntin s t sts); a r s r r s ti n str a t t a at t sa g ti t r a nstant r ss r r a an a r s r r a nstr a fr t a at r-nt g ts t ar t a r ss r a ting n t a

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r ng t sting t g t f t r s r r as ang t r a a r ss r rang ng t n 28 t 128 g (5 g st s) t n 2 ns ti as r nts a r ss r as s t t r g t a t a t r

-r ts n tia n g -rati n r g rg tati n rat at a a r ss r as as r s ng a trans t-ti tra-s n t r ( 110 s r s rans n S st s) Pulsatile tests as n a r s r (30) a n s at r as s gn an t t rf r sati t sts ( g 2 ) It ns sts f t f ng nts: a t-r ng s st a ntr ar a r an a rti a s ng a s st an s at r an a tra a s ng tr ng s st an t s st -an s at r a n r s s r n ta (30) ng s st as r n an tr n n-tr r a ng t s ng f r nt rat a f r s an r nt fr n s In t s r t s st rat as r at t S ans n an ar a f r (31) a a r an rat a f r (32) as s t r r t ast rat ntr -ar a r a s t s ati n f t s g a an at g a str (S ) ntr ar a -r an t ng s st ar a t n s n ran (t n ss 0 3 ) s a t st n an s at an t sti at r t r nt a -ag t t an a s st t t r nts f t s at r an t r nt s ( g r s s ating t r g a r rti s) f r r a rti an t tra a s ng ar t sa s f r t ntin s t st an ar nn t t stra g t t s t t s st an s at r an t t ntr ar nt r s ti rt r r t s s t a s t r t s a s r ati n f t a s at r nt ti st s f t A r ng t t NI N ISO 58 0 Stan ar t n s at r r r s t s g a r ss r an a f r s ( g 3) ( art r a a s st r ss r rang ng fr 100 t 130 g art r a ast r ss r fr 65 t 85 g r ntia r ss r a r ss s a rti a a t 95 g) - a s r t st at r nt rat s an a r ss r s as r r t NI N ISO 58 0 Stan ar Fig. 1 - (A) A n (B) s t an (C) t r f - a ns ns ar : a t 10 ∼10 9 ; t t 21 ; nt 21 ; t 28 ; tiss ann s a t r ( A ) 21 ; t n ss a t 0 36∼0 2

Fig. 2 - O t n f t t st n s: (A) r nta s t f r ntin s t sts (B) r nta s t- f r t sati t sts ati ns f str a an nstr a r ss r an rat r s ar s n n t s t ; t s r ati n nt fr t r s r ta n s n at t s

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rans a ar r ss r r as as r at a nstant fr -n ( 0 ) an ar a rat (2 3 5 5 an n) g rg tati n as t r n t sting a a at a an rat f 5 n at 3 r nt fr n s ( 5 0 120 ) At a fr n 3 a r ss r s r t st (80 120 160 g) S tan s as r nts r r r s ng trans t-ti tras n -t r an r ss r -trans rs at 35 str a an 105 nstr a fr t a rti a rans a ar r ss r r r g rg tati n ( ) r g rg tant fra ti n ( ) an s st r ss r r n ( S ) an ti r ar a ( OA) r a at f r a a ati n 1 as s t a at S

= =∆ MSPD pi n i 1 n 1 r i s t r ss r r n a r ss t a n g an n s t n r f sa s r ng t s st as ati n 2 fr ISO 58 0 (29) as s t a at OA = ρ ∆ EOA Q 51.6. p RMS 2 r s t an r ss r r n n g s t ns t f t t st n gra s r nti tr an Q S s t r t an s ar f f r ar n tr s r s n g n ati n 3

= − Q Q(t) dt t t RMS 2 t t 2 1 1 2 3 r (t) s t nstantan s at ti t t1 an t2 ar ti at start an n f t f r ar r s ti g rg tati n s g n ati n

= RG Q(t) dt t t 3 4 r t3 an t ar ti at start an n f t a ar r s ti s a at ati n 5 = RF% RG SV.100 5 Statistical analysis a a as n t st f r at ast 15 ns ti s at a t st n ti n S SS Statisti s rs n 21 (I ) as s t rf r statisti a t sts A ata ar r rt as an stan ar ati n (S ) In n nt-sa s t-t st as s t t r n statisti a s gn ant r n s t n t gr s S gn an f r t t sts as s n at 0 01 Fig. 3 - r ss r an tra ngs a r r ng a sati t st fra (A) r rts t s st r s-s r gra nt r ti a t a a f r A an t an s s-t r ss r r n ( S 8 g) t r s s t a r f t 2 gr s f a s (solid line r A an dashed line r ) at r nt nstants r ng ti : (B) ar ast (C) n

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results

Continuous flow test

r A s a statisti a r ( 3 2 - ) an trans a ar r ss r r (8 36 1 33 g) t an r (15 26 1 8 g) at t a rat (10 n) ( g A) A s t an r g rg tat n s a r A as r (1 5 3 19 n) t an r (26 26 n) ( g ) t t ff r n s stat st a ns g-n f ag-nt ( 0 0 ) s a ff r n n r g rg tat n t n t 2 gr s a as r t t ff r nt a ag ar a f r r ng t a s ng as ( g )

Pulsatile flow test

A t t st - a s t n rf r-an r r nts s t t ISO 58 0 Stan ar ( g 5): a t 16 s s OA 1 2 an a r g rg tant 10 f t str (S 1 ) n rf r-an r r nts rr s n t t f ng sati -n ti -ns: art rat 0 s n s at ar a t t 5 0 n S 1 an a rti r ss r 100 g an s st rati n 35 r A s statisti a g r OA (1 5 0 21 2) t an r (1 21 0 12 2) ( 2 29 - ) an r g rg tati n as ara t n t 2 gr s ( 13 1 33 f r A s 6 60 0 9 f r ) ( 0 05) Fig. 4 - s ts f ntin s t st: (A) ar s n f trans a ar r ss r r s t n t 2 gr s f a s ( ata ar r rt as an a ng 8 a s S ) (B) t r s f 2 - a s (t a fr r A; a fr r ) at 2 r nt rat s (0 n n t an 10 n n t r g t) (C) ar s n f r g rg tati n -t n t 2 gr s ( ata ar r rt as an a ng 8 a s S ) (D) t r s f 2 - a s (t a fr r A; a fr r ) r ng stati r g rg tati n t sts at 2 r nt a r ss r s (28 g n t an 128 g n t r g t)

Fig. 5 - OA (A) an r g rg tati n (B) ( str ) f r t 2 gr s f a s r ng sati t sts n ti ns: rat 0 n ar a t t 5 0 n an a rti r ss r 100 g an s s-t rati n 35 r nta n s n at t ISO 58 0 s ati ns f r t sa sati n ti n

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t sts s t at t S r r n r A as statisti a r (12 20 1 1 g) t an n r (1 09 3 39 g) ( 0 0019) A s t a trans a ar r ss r r s r sta-tisti a r nt ( 3 3 -05) t n r A an r r A s a a r ss r r a t 30 09 g n r t as 3 98 52 g Discussion St a stat an sati r na t sts r r-f r t a r nf r ati n an n at rs n t an a a r f - a s an fa t r fr rs a ng r nt st r n nt nt r s ts fr ntin s an sati t sts nstrat t at t trans a ar r ss r r s r at t t sti n ss f t r n r as s t st r n ass r nt-ag n t at r a ( gs A an 5A)

r n s t n r A an r f r t OA an an trans a ar r ss r r s ar statisti a s g-n ag-nt as nstrat n n nt-sa t-t st

s r n s an a n t g r an a str ngt f t r t at nstit t s t a s ng-ng t r f ar t t at r a nstit ting a s ng ng t r A As a a r f fa t ng nstant a t t r n ti ns a g r at r a sti n ss s r s ns f r a s a r a t f r ati n r ng t s st as an ns nt f r a r a n ng s r s t an as r t t r a t f r-ati n ta n r ng t s st as n t a s -ng -ng t r ; n fa t t g r st r n g t fra ti n ara t r ng t r n t s a s n s sti r a t a r t s r s ting n a r a n ng - a s s g n ng an s ng rf r an -s ( g 3) ng t a r f nat ra art a s r g rg tati n n t ntin s t sts s r n r A t an n r ; n rs f r t sati t sts t r g r-g tati n s r n r t an n r A r n t t sts t r n s statisti a ns gn ant t n t 2 gr s A t 16 - a r t t s t t n r -r nts s n t ISO 58 0 Stan ar t n t r s f r g rg tati n an OA ( g 5) nstrating t r -ti n ss r t r nta t sts rf r n t s Fig. 6 - ar s n f t - a r na rf r an s ( OA an g rg tati n r g t) t t rat r ata (33 3 ) f r tiss an an a art a s at t f ng sati n ti n: art rat 0 n s at ar a t t 5 0 n an a r-ti r ss r 100 g an s st rati n 35 st r t at t a s ng ng t r A s r a r n t r s f OA an an r ss r r s r a t t r sti n ss f t a ts a s a r n ng r rf r an s s a t a s ng-ng t r A s gg st t at rs a ng r t an a 30 st r n fra ti n s s n f r - a an fa t r ng na a r s a t 2 gr s f - a s t st n t s st r ar ( g 6) t t rat r ata f r r a art a r st s s a -ng t sa tiss ann s a t r ( A ) as - a s: 5

an a (33) an 5 g a (3 ) t OA an r g r-g tati n f an a an tiss art a r st s s ar

ara t t ata ta n f r - a s an -a -art -a s s t g st an t ta r g rg tant (rang ng fr 6 08 1 23 t 10 8 1 53 ) an OA (fr 1 3 0 11 2 t 1 90 0 10 2) tiss a s s t st rf r an s n t r s f an r g rg tati n (fr 3 86 0 85 t 1 96 1 26 ) r s ts f t s -ar s n s t at t r na a r f - a s a a t a a a t rnati t t a r st s s rr nt a a a n t ar t ( g 6) ra t f t - a n t n n s n t an a r rti s f t a at r a s t a s -n s -n t a-n fa t r -ng t n an n t str ss str ti n n t at r a r t r na as-s as-sas-s nt r s nt n t s a r t g t r t t s ti r s ts f t ra t t sts a a f r r st ti art a as n st r n r as s - a an a ra ti a t rnati t t an a an r a s rr nt s Disclosures

nan a s rt: s r as f n t r tis art n-ati n N r ns grant N 11 29059 n t f nt r st: N n f t a t rs as nan a nt r st r at t t s st t s s references 1 an as ganat an A nt A an s n r art a s s ar Int J at r s ng 2011;1(1):1-1

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2 S a SS r s r J n ati s f s nt ti a t art a s r ng a rat t sting J art a s 2003;12(1):110-119

3 as ar rr J S n A ganat an A -na ass ss nt f t r r art a s s ng ar-ti ag tr Ann ng 2006;3 (6):936-952 an ar atg an A rr s a a S -fa an A r art a s: n at r a s rg ng s r n s t n 2009;2 (6):359-36 5 a r n J an n t r st ti art a s: at r ng f r t f at r a s 2008;29( ):385- 06 6 a a rna a s r A n S at J In vitro f n ti n an ra t ass ss nt f a n r t an art a r st s s Artif Organs 1996;20(9):101 -1025.

rna a a a ns n at J r

-t an ar-t a s: fa-tig fa r a ati n an r -t an s-tr -t r J at r s 199 ;3 (3):3 1-3 9 8 rna a Stra I at J an a an r

-g a st f sta r t an art a a ts -ant fr s J at r s 2002;61(1):138-1 5 9 a r t S a st n r anns t a N

r art a r st s s f r t tra an a rti s -ti ns art S rg r 200 ; (5): 525- 532

10 Sa JS a r t S N an a r

a r st s s t s a s gn f r a rti an tra -s ti n: a f t r ti n f r atr ati nts ASAIO J 2006; 52(5):5 5-580

11 Ara a A sa S t t a atr r g t art trans antati n: a ati n f t r n art s an rat ntr ar ass st s J art ng rans ant 2006;25(1):16-21

12 Sa a ns J O a a t n S fa an A r -an a -ana s s f a ant ( ar nat r a) r -t an a r s r t r ti ati r ati an g a s ti ns at r a s 2002;23(10):2231-22 0 13 an A rr s r s ng an ar n r S fa an A A n nan s t r f r -nt f s -nt ti art a a ts A ta at r 2009;5( ):2 09-2 1 1 an ar atg an A rr s a a S -fa an A r art a s: n at r a s rg ng s r n s t n 2009;2 (6):359-36 15 an ar an A rr s a s ar s r A S fa an A anti- a ati n t ntia f a s s s -an n-an s t r n r in vitro n ti ns: t n-tia at r a f r s nt ti a t art a A ta at r 2010;6(11): 2 9- 260

16 n r as A a a J a A r n r S a r n ar f r ati n f a n ar-s ng - r sta

tr r t a n r a r g 1 S n r -tr n SA S a r s 2000;33(25):9395-9 06 1 a rn S r J ng St ns f r S an J st n In vitro a ati n f a n na a -ti tr a t r r st ti art a J ng 2013;135(2):021021 18 a rn st n S rst r nt an a ati n f a n arti a at t r- ra r s-t s-ti ars-t a an t f r in vitro t sting Int J Artif Organs 2009;32(5):262-2 1 19 Stas a J Na r S ggr g an a str ngt f s -t r rs s f r a ar ng a a a-ti ns at r ng 201 ;2 (1):563-569 20 Stas a J ggr g a ra A an A stantin ng n r ng r ntati n n rs f r a a-ti n t r st a-ti art a s n ti na at r a rs 2010;3( ):2 9-252 21 ra s a N s n S rst r A s - st r n - s t n - st -r n (SI S) t-r r f r n an ati t

an t ntia s n arti a art a s J at r A 2009;23( ):36 -3 9 22 n s n J arr JJ S rst r ar J nn J a a ati ns f (st r n - - s t -n - -st r n ) ( SI S ) at r a s 2008;29( ): 8- 60 23 ra r ans s as J A tst t ati t an fatig r rti s f st r n - s t n - -st r n an rg ng t r asti ast r at r a a r s 2006; (3):8 -850 2 a r S Ag rr A as an n S rst r A n r f r t ntia s n a tr a t art a J at r s A at r 2006; 9 (2):325-33 25 ang r n AJ an at n S

r-st r In-vivo ass ss nt f a n r (SI S) tr a t art a J art a s 2010;19( ): 99-505 26 Stas a J S r s A ast a I ggr g t f Str t ng n t Str t r f n r- an S r -r ng St -r n Is -r n St -r n rs a r -s 2009; 2(1 ):5256-5265 2 Stas a J r rt J S rran t a A - ns r r str -t r n s n ti n ng f n r a rs S a r 201 ;10(32):60 -6086 28 a tan agn a ra A t a A n tr - a t r art a r st s s J 2015;15(2):15 0009 29 ar as ar ants ar a a r st s s ANSI AA I ISO 58 0: 2005;2005 30 an ar n s ara r A n sati tr t r a s f r t in vitro st f t ar-as ar s st Artif Organs 2009;33(12):10 8-1062 31 S ans n ar A s ar as ar s st s -at r: s gn an rf r an J ng 19 ;1(2):135-1 5 32 a r N an s f Nat ra ar a a s In: a r ss s Art r a S st r n -rg: S r ng r 19 8; 269-2

33 a r asar r sa S a a rti ann -s: t r na rf r an s f 5 r a a a -a a t an a a s J ra ar as S rg 200 ;128(3): 5 - 62 3 r sa ar a S a a rti ann s: t r na rf r an s f 5 r a a a a tiss a s J ra ar as S rg 2006;131(5):1058-106 2

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In this chapter we will first give an overview of the dynamics of strings and domain walls in the early universe, and then discuss the evolution of the axion string system based