1 Effct of Elctrical Stimulation on Bactrial Growth By Jrrold Ptrofsky Ph D Michal Laymon DPTSc* Wndy Chung DPTSc Klly Collins BS* Tin-Ning Yang BS* Dpts. of Physical Thrapy Loma Linda Univrsity Loma Linda, California and Azusa PACific Univrsity* Azusa California Snd rprint rqusts to: Dr. Jrrold Ptrofsky Profssor and Dirctor of Rsarch Dpartmnt of Physical Thrapy Loma Linda Univrsity Loma Linda California, (909)
2 Abstract Background; Elctrical stimulation has bn usd as a modality for many yars for wound haling. On of th mchanisms proposd for why it works is that lctrical stimulation is blivd to b bactria static. Howvr, arly studis making this claim usd much gratr than normal stimulation voltags and currnts. Mthods and procdurs; In th prsnt invstigation, 3 typs of bactria, Eschrichia coli, Psudomonas aruginosa, and Staphylococcus aurus wr xamind with physiological lvls of AC (5 and 20 ma) and DC lctrical stimulation to s if ths sam currnts that travrs through tissu during normal lctrical stimulation for wound tratmnt could impair bactrial growth. Rsults; DC micro currnt did not altr bactria growth for any of th thr bactria studid. Psudomonas aruginosa showd significantly rducd growth with both (5 and 20 ma) AC currnt intnsitis (p<0.05) whras th othr bactria showd no consistnt rductions in growth with AC currnt; ach showing som snsitivity to AC stimulation. Whil thr wr significant diffrncs btwn th ph of th culturs with AC stimulation in th xprimntal vs. th control groups in som conditions, thr was no consistncy in any corrlation btwn ph and growth. Thus, whil psudomonas was inhibitd with AC stimulation, thr was no vidnc from ths studis that lctrical stimulation had a consistnt bactria static ffct on th othr bactria. Evn in psudomonas, bactria growth was only slowd and not stoppd with 30 minuts of stimulation. Conclusions; whil thr was som snsitivity at last in on bactrium to AC stimulation, largly th bactria static ffct of lctrical stimulation undr th conditions usd hr was d minimis. Ky words: wounds, lctrical stimulation, bactria, haling
3 Introduction Wound haling, spcially in popl with diabtic nuropathis, can b xtrmly difficult to accomplish. 1 For xampl, of popl who hav diabtic ulcrs on thir ft, inability of wounds to hal causs an avrag amputation rat to b about 25% 2,3. Many 2, 3, 4 diabtic ulcrs and vn dcubitus ulcrs can tak months, yars, or nvr hal at all. This inability of convntional mdical practic to hal wounds has bn trmd a failur of th halth car systm. 5 Evn nwr thrapis such as myocutanous flaps, watr dbridmnt, and othr tchniqus hav not incrasd th haling rat apprciably in th past fifty yars or th rat of roccurrnc. 5 On modality that has bn studid is lctrical stimulation. 6 Many paprs point to th us of lctrical stimulation across wounds to incras wound haling. 7, 8 Howvr, vn this tchnology dos not always work. Som paprs show wound haling with DC micro currnts whil othrs show only haling with strong AC currnts. 9, 10, 11 Som paprs rport that in th arly stags of wound haling th polarity nds to b positiv nar th wound and ngativ away from th wound and othr paprs rport th opposit. 12, 13, 14 In fact, in a summary of diffrnt studis on wound haling, Yarkony rportd nothing conclusiv in stting th intnsity of currnts, whthr it was DC or AC stimulation or th frquncy of lctrical stimulation in th ability of lctrical stimulation to hal wounds. 12 Rcnt vidnc, howvr, links this disparity to possibly bing linkd to room tmpratur. Vasoconstriction of th circulation during tratmnt du to a cool or cold xamination room blocks th blood flow incras du to lctrical stimulation of th wound. If th room is warmd, blood flow incrass and wounds hal 15, 16 wll with lctrical stimulation.
4 Numrous mchanisms hav bn suggstd on why lctrical stimulation promots wound haling including incrasd circulation, 1,17 18, 19, 20 incrasd angiognsis incrasd prolifration of pidrmal tissu, and a bactria static ffct of lctrical stimulation. 21 Th possibl bactria static ffct of lctrical stimulation was first rportd ovr 30 yars ago by Rowly & McKnna. 22, 23 Using high voltag lctrical stimulation (300 volts), bactria (E. coli) did aftr a brif sssion of lctrical stimulation. Whil a fw studis hav usd similar voltags for clinical lctrical stimulation of wounds 11, 24 most studis that rport haling us a fraction of ths voltags and currnts. 12, 13, 25, 17 Th stimulation voltags usd by Rowly t al. would b xtrmly painful for th patint. Furthr, sinc DC micro currnt has bn shown, in som studis, to aid in haling of wounds, whn th voltags usd by Rowly and collagus ar compard to DC micro currnts, thy ar thousands of tims highr. Thus, th currnts usd in ths studis wr not clinically rlvant and, thrfor, th application of ths studis to ral lif situations is qustionabl. Th prsnt invstigation was conductd to study th ffct of lctrical stimulation on bactrial growth in thr common bactria that ar sn in wounds, Eschrichia coli, Psudomonas aruginosa, and Staphylococcus Aurus. 23, 26 Ths bactria wr grown in cultur and thn xposd to ithr DC microcurrnt (100 µamps) or biphasic sin wav stimulation at 5 or 20 ma for 30 minuts. Ths currnts ar normal currnts usd in wound haling. 16, 15 Bactrial growth was thn assssd aftr 24 hours of incubation to s if th normal currnts that ar usd with lctrical stimulation clinically to hal wounds can altr bactrial growth.
5 Mthods Bactria- Bactria wr grown in a soy broth (tryptic soy broth, soyban- casin digst) from Hardy Diagnostics (Cat # C7141, Santa Monica, CA). Th bactria usd wr Eschrichia coli, Psudomonas aruginosa, and Staphylococcus aurus. Ths bactria wr obtaind from stock concntrations (Micro biologics, ST Cloud, Minnsota). Bactria wr grown in broth at a tmpratur of 37 o C until th concntration of bactria was btwn 4-5 on th McFarland Scal. 27 All bactria wr grown and tstd for activity by standard microbiological light microscopy. Th broth was tstd for growth in an absorption spctromtr at a wavlngth of 580 nanomtrs; th rlationship btwn bactrial dnsity and broth absorption was stablishd. Onc this was stablishd, stock broth culturs wr placd btwn two 2 X 2 cm carbonizd rubbr lctrods, so that thy could b subjctd to lctrical stimulation for a priod of thirty minuts. Th sparation distanc btwn th lctrods was 10.3cm. Th covrd cultur siz was 10.3 X 8.5 cm and 6.75 cm dp. Th volum was 400ml. Using ths lctrods and lctrod sizs, th impdanc of th broth was 1280 ohms during lctrical stimulation, a valv similar to that rcordd across wounds. 15 Th siz of th broth holdr was slctd so that if currnt was masurd ovr a 0.5 cm distanc in th broth, th rcordd currnt was 15, 16 similar to that rcordd in human wounds.
6 Elctrical Stimulation- AC lctrical stimulation was providd by a challng 8000 powrd muscl stimulator (MPTS Tustin, CA). This stimulator providd 4 channls of currnt controlld output with a biphasic sin wav at 250 µsc puls width and a frquncy of 30 Hz. DC stimulation was providd at a currnt of 1 ma by a battry with a rgulatd currnt controlld output. ph- Th ph was masurd with an Accrumnt Basic AB15 ph mtr (Fishr Scintific, Singapor).
7 Procdurs Using th stock broth bactrial culturs dscribd abov, ach of th 3 bactria wr placd in a bactrial broth in th rctangular culturs. Aftr th broth had bn culturd, lctrical stimulation was applid for thirty minuts. AC currnt was dlivrd with biphasic lctrical stimulation (sin wav) at a frquncy of 30 Hz and a puls width of 250 microsconds at intnsitis of ithr 5 or 20 ma for a priod of 30 minuts. Th stimulation output was currnt controlld. DC stimulation was also applid for 30 minuts. Th bactrial cultur along with culturs whr no stimulation was applid, wr thn placd back into th incubator for anothr 24 hours and growth was assssd. Th procss was rpatd on 8 culturs for ach bactrium. Statistical Analysis- Statistical analysis involvd th calculation of mans, standard dviations, and t tsts. Valus in th txt ar shown as th man+/-sd. Th lvl of significanc was p < 0.05.
8 Rsults Initially, th McFarland Scal was calculatd at a frquncy of 580 nanomtrs for ach of th bactria. Absorbncy at this frquncy was plottd against st concntrations of bactria to obtain a calibration curv. Th corrlation btwn th concntrations of bactria to th absorbncy was This yildd an R 2 of and, th quation rlatd concntration to absorbncy was Y = x. Givn th calibration on th McFarland Scal, broth was mixd and th studis wr compltd as dscribd undr procdurs. Th rsults for ach bactrium ar listd blow. Eschrichia coli - Th rsults showing growth in Eschrichia coli ar shown in figur 1, panl A and B. Panl A, in figur 1, shows th bactrial colony growth from th bginning to th nd of th study (24 hours aftr th initial incubation). As shown in panl A of figur 1, with a currnt of 5 milliamps, th incras in bactrial colony growth ovr 24 hours was 365 +/- 57 x 10 6 bactria pr millilitr whras for 20 milliamps stimulation th incras in growth was 366 +/- 16 x 10 6 bactria pr millilitr. For th controls, whr no stimulation was accomplishd, bactrial colony growth incrasd by 401 +/- 7.5 X 10 6 bactria pr millilitr ovr th 24 hours. Thr was no statistical diffrnc btwn growth in th 5 and 20 ma and control groups (p < 0.01). Bactrial colony growth for DC stimulation was 460 +/- 74 x 10 6 bactria pr millilitr. Th only significant growth rduction compard to th controls was for stimulation at 20 ma (p<0.01). Hr, howvr, th rduction in growth was only 9.8%.
9 ph was also masurd at th bginning and at th nd of studis. For th control bactria colonis (no stimulation) ph startd at / At th nd of th 24 hour priod, ph avragd /- 0.18, a rduction of an avrag of 1.22 ph units. For bactrial stimulation at 5 and 20 milliamps, thr was a significantly gratr rduction in ph ovr th 24 hours compard to th control colonis (p > 0.01). Th chang in ph was small, avraging 0.4 ph units. For DC stimulation, th chang in ph, ovr th 24 hour priod was not significantly diffrnt than that of th controls (p > 0.05). Thr was no corrlation for any group in ph and bactrial growth (p>0.05). Psudomonas aruginosa- As shown in th top panl of figur 2, undr all four conditions, thr was an incras in bactrial growth ovr th 24 hour priod for ths colonis. As shown in panl A of figur 2, th incras in bactrial growth with 5 milliamps of stimulation avragd 204 +/- 116 x 10 6 pr millilitr, for 20 milliamps stimulation avragd 228 +/- 121 x 10 6 bactria pr millilitr and aftr DC stimulation avragd 331 +/- 161 x 10 6 bactria pr millilitr ovr th 24 hour priod. Th growth for all conditions was significantly lowr than growth for E. coli (p< 0.05). Compard to th control group, th bactrial growth ovr th 24 hour priod was significantly lss for th AC stimulation than for th control group (p<0.05). Bactrial growth avragd a 38% rduction in growth with AC stimulation. For DC stimulation, thr was no significant diffrnc to th growth of th control group (p>0.05). As shown in th bottom panl of figur 2, th ovrall chang in ph was lss than that obsrvd for E. coli (p < 0.01). Howvr, th rduction in ph, which avragd /- 0.5 in th control group, was only statistically lss with stimulation at DC and 20 ma
10 AC (p<0.05). Thr was a significant corrlation btwn ph and growth only for stimulation at 20ma. (p<0.01) Staphylococcus aurus- Figur 3 shows th rsults of th Staphylococcus xprimnts. As shown in th top panl of figur 3, th avrag chang in growth for ths bactria was 358 +/- 8 x 10 6 bactria pr millilitr aftr stimulation with currnts of 5 milliamps, 376 +/- 20 x 10 6 bactria pr millilitr aftr stimulation at 20 milliamps and 405 +/- 69 x 10 6 aftr DC stimulation. Only th growth aftr 5ma AC stimulation was diffrnt than that of th controls (p < 0.01). Howvr, th rduction in growth was only 3.9% compard to th control group. As shown in th bottom of th panl, th ph was diffrnt in th 5ma group compard to th control group (p<0.01). Thr was no diffrnc btwn th DC and AC 20 ma groups compard to th control groups (p>0.05). Thr was a significant corrlation btwn ph and growth in th 20ma and DC groups (p<0.01).
11 Discussion On of th mchanisms causing wounds to not hal is bactrial invasion. 21 Bactria ruptur cll mmbrans and maintain chronic inflammation to prvnt wound haling 27 Many studis show that ithr DC microcurrnt or low currnt AC stimulation has th ability to incras wound haling. 6, 9, 10, 17 In arlir studis, Rowly and collagus publishd data showing that lctrical stimulation has a bactria static ffct on Eschrichia coli and svral othr bactria. Barranco t al. 28 showd inhibition in Staphylococcus aurus growth with 400µA DC stimulation. But th lctrods wr mtal and at 400 µamps, corrosion was notd. Othr in vitro studis with 100 µa DC stimulation also showd a bactria static ffct but hr silvr lctrods wr also usd. 29, 30 Othr studis showd a bactria static ffct of DC at 1, 5, or 10 ma but not AC 22, 23 stimulation. 31 Ths studis showd larg changs in ph with DC stimulation, probably du to th fact that, unlik clinical situations whr stimulation is a 30 minut modality, th currnt was lft on for hours. 32 This ph chang was sn also with AC stimulation at 500 volts. 33 But ths studis wr conductd in vitro with a small sparation distanc btwn th lctrods. Thus th currnt pr mm of distanc on th bactrial culturs wr larg. Furthr, mtal ions lik silvr can kill bactria in thmslvs. In addition, ths studis wr conductd at vry high stimulation voltags (ovr 300 volts). In wounds, nrv ndings ar snsitizd by th rlas of cytokins. 34 Evn mild lctrical stimulation can thrfor b painful. In prvious studis, 16, 1, 15 th currnt usd to hal wounds was lss than 20 ma. Thrfor this was th currnt usd in ths studis.
12 In th prsnt invstigations, th dnsity of th broth, siz of th chambr and siz of lctrods wr adjustd so that th lctrods wr sparatd by th distanc sn in a typical wound tratmnt. 15, 16 Th impdanc of th broth matchd that of a human wound, about 1200 ohms btwn th lctrods. This, in itslf, is diffrnt than prvious studis whr larg currnt dnsitis wr sn du to high voltags bing applid to small bactria culturs. Whil w usd a larg chambr for th broth, th currnt dnsity may hav still bn somwhat highr thn in a limb du to th highr volum in a limb. Howvr, whil currnt dnsity may hav bn somwhat highr than in a wound hr, arlir in vitro studis usd a fraction of th volum usd hr btwn th lctrods and lctrods wr closr togthr making currnt dnsity in.g. Rowly t al 22, 23 much highr than in wounds. Whn currnts wr applid in th prsnt xprimnts for a 30 minut stimulation priod, similar to a standard tratmnt priod for wound haling, DC stimulation had no ffct on bactria growth. AC had som ffct on ach of th bactria but th only ral ffct on growth with lctrical stimulation was on psudomonas. Any ffct sn on Eschrichia coli and Staphylococcus aurus was small. For psudomonas, th growth rduction at ithr AC currnt was larg. Howvr, bactria can still b dstroyd by lctrical stimulation through anothr mchanism in wounds. Elctrical stimulation and, lctrical stimulation of wounds causs th rlas of prostaglandins and othr cytokins. 35, 36, 37, 38 Ths prostaglandins and othr cytokins attract macrophags to th ara whr lctrical stimulation is applid. 31 Thrfor, although lctrical stimulation may not hav a dirct ffct on bactria in wounds, thr is som vidnc that whit blood clls such as macrophags
13 ar attractd as a scondary ffct of th lctrical stimulation, this may xplain why lctrical stimulation may b associatd with bactrial dath. Th prsnt studis still rmain in dirct contradiction to th studis by Rowly t al showing a dirct ffct of lctrical stimulation on inhibiting growth in Eschrichia coli. Howvr, whil Eschrichia coli and Staphylococcus aurus showd ithr a statistically insignificant chang in growth or an insignificant clinical chang in growth with lctrical stimulation, this is not to say that lctrical currnt dos not altr bactrial bhavior. Bactrial motility and attachmnt to substrats appars to b impaird by stimulation with lctric currnts (39). This is spcially tru for psudomonas whr flaglla ar ndd for mobility (40). Th fact that psudomonas hr did hav som impaird growth may b du to th fact that thr ar two flaglla protins involvd in its mobility and attachmnt- if ithr is impaird, growth is rducd 41. Hr, ths flaglla, sinc thy us contractil protins and ion channls for movmnt, may b impaird with lctric currnt. This maks ths bactria diffrnt from th othr 2 which do not mov by this mchanism. 22, 23 Howvr, thr ar conditions whr lctrical stimulation will inhibit growth in all 3 bactria. Whil currnts of up to 20ma in thmslvs with ths sam bactria did not rduc bactrial growth 39,42, in combination with antibiotics, th rducd ability of th bactria to attach to substrats mad thm mor suscptibl to attack by th antibiotics. Thus whil antibiotics alon or lctrical stimulation alon did not kill ths bactria, th combination of th two did 39,42. Thus, lctrical stimulation with ithr DC or wak AC currnts may hav an unsn ffct which may kill bactria in vivo but not undr ths circumstancs in vitro. Furthr invstigation is warrantd. Hr, for xampl, currnt
14 was usd for 30 minuts, a standard tratmnt modality. Prhaps longr xposur to currnt would hav a mor dramatic ffct in vivo.
15 Rfrncs 1. Ptrofsky, J.S. Schwab, E., Lo, T., Cuno, M., Gorg, J., Kim, J., & AlMarty, A. (2005). Effcts of Elctrical stimulation on Skin Blood Flow in Controls and in and around Stag III and IV Wounds in Hairy and Non Hairy Skin. Md Sci Monit, 11, Knndy, E.J. (1999). Spinal cord injury; th facts and figurs. Th Univrsity at Alabama Prss: Birmingham, Alabama. 3. Snt, P., & Maum, S. (1999). Dcubitus sors in griatric mdicin. Local and gnral tratmnt of prssur sors in th agd. Prss Md, 28, D Astis, V., Corblla, A., Bafico, F., Spinlli, E., Porcu, G., Bottari, L., Ptrini, M., & Madddu, V. (1999). Dcubitus lsions in patints rfrrd to acut and post-acut hom nursing car for th ldrly in Gnova. Assist Infrm Ric, 18, Mhan, M. (2000). Byond th prssur ulcr blam gam: rflctions for th futur. Ostomy Wound Manag, 46, Kloth, L.C. (2005). Elctrical stimulation for wound haling: a rviw of vidnc from in vitro studis, animal xprimnts, and clinical trials. Int J Low Extrm Wounds, 4, 1, Ennis WJ, L C, Mnss P. (2007) A biochmical approach to wound haling through th us of modalitis. Clin Drmatol, 25(1): Bogi KM, Triolo RJ (2003) Effcts of rgular us of nuromuscular lctrical stimulation on tissu halth. J Rhabil Rs Dv. 40(6): Fdar, J., Kloth, L., & Gntzkow, G. (1992). Chronic drmal ulcr haling nhancd with monophasic pulsd lctrical stimulation. Phys Thr, 72, Frank, A., Frank, E., & Grzsik, J. (1999). Elctrically nhancd damagd tissus haling. Part II: dirct and puls currnt in soft tissu haling. Pol Mrkuriusz Lk, 40, Houghton, P.E., Kincaid, C.B., Lovll, M., Cambll, K.E., Kast, D.H., Woodbury, M.G., & Harris, K.A. (2003). Effct of lctrical stimulation on chronic lg ulcr siz and apparanc. Phys Thr, 83, 1,
16 12. Yarkony, G.M. (1994). Prssur ulcrs: a rviw. Arch Phys Md Rhabil, 75, Bogi, K.M., Rgr, S.I., Lvin, S.P, & Sahgal, V. (2000). Elctrical stimulation for prssur sor prvntion. J Assist Tchnol, 12, Dmir, H., Balay, H., & Kirnap, M. (2004). A comparison study of th ffcts of lctrical stimulation and lasr tratmnt on xprimntal wound haling in rats. J Rhabil Rs Dv, 42, 2, Ptrofsky, J.S., Schwab, E., Cuno, M., Gorg, J., Kim, J., AlMarty, A., & Lawson, D. (2007). Intraction btwn rsting skin blood flow and th blood flow rspons to lctrical stimulation in normal and woundd skin. Submittd Md Sci Monit 16. Lawson, D., Ptrofsky, J.S., (2007). A randomizd control study of th ffct of biphasic lctrical stimulation in a warm room on blood flow and haling rats in chronic wounds of patints with and without diabts. Md Sci Monit 17. Kloth, L.C. (2002). How to us lctrical stimulation for wound haling. Nursing, 32, 12, Bai H, McCaig C.D, Forrstr J.V, & Zhao M. (2004). DC lctrical filds induc distinct prangiognic rsponss in microvascular and macrovascular clls. Artriosclr Thromb Vasc Biol, 24, 7, Zhao, M., Bai, H., Wang, E., Forrstr, J.V., & McCaig, C.D. (2004). Elctrical stimulation dirctly inducs pr-angiognic rsponss in vascular ndothlial clls by signaling through VEGF rcptors. J Cll Sci, 117, Ojingwa, J.C., & Issroff, R.R. (2003). Elctrical stimulation in wound haling. J Invst Drmatol, 121, 1, Rowly BA, McKnna JM, Chas GR, Wolcott LE: (1974) Th influnc of lctrical currnt on an infcting microorganism in wounds. Ann NY ACad Sci 1974b 238: Rowly BA, McKnna JM, Wolocott LE (1974) Procdings: Th us of low lvl lctrical currnt for nhancmnt of tissu haling. Biomd Sci Instrum, 10: Rowly BA (1972) Elctrical currnt ffcts on E. coli growth rats. Proc Soc Exp Biol Md 139(3): Polak, A., Frank, A., Hunka-Zurawinska, W., Kucharzwski, M., & Swist, D. (2000). High voltag stimulation in lg ulcr s tratmnt. Wiad Lk, 53, 7-8,
17 25. Spilholz, N.I., & Kloth, L.C. (2000). Elctrical stimulation and pulsd lctromagntic nrgy: diffrncs in opinion. Ostomy Wound Manag, 5, Hossini SV, Tanidh N, Kohantb J, Ghodrati Z, Mhrabani D, Yarmohammadi H. (2007) Comparision btwn Alpha and silvr sulfadiazin ointmnts in tratmnt of Psudomonas infctions in 3 rd dgr burns. Int J Surg, 5(1): Nubaur T, Bayr GS, Wagnr M. (2006) Opn fracturs and infction. ACta Chir Orthop Traumotol Cch. 73(5): Barranco S, Spadro J, Brgr T (1974) In vitro ffct of wak dirct currnt on Staphylococcus aurus. ClinOrthop 100: Ong P, Laatsch L, Kloth L. (1994) Antibatrial ffcts of a silvr lctrod carrying microamparag dirct currnt in vitro. J Clin Elctrophysiol 6(1): Laatsch L, Ong P, Kloth L. (1995) In vitro ffcts of two silvr lctrods on slct wound pathogns. J Clin Elctrophysiol 7(1): Guffy J, Asmussn M. (1989) In vitro bactricidal ffcts of high voltag pulsd currnt vrsus dirct currnt against Staphylococcus aurus. J Clin Elctrophysiolo 1: Nwton R, Karslis T. (1983) Skin ph following high voltag pulsd galvanic stimulation. Phys Thr 63(10): Szuminsky N, Albrs A, Ungr P (1994). Effct of narrow, pulsd high voltags on bactrial viability. Phys Thr 74: Hrnandz R (2006). Th us of systmic antibiotics in th tratmnt of chronic wounds. Drmatol Thr. 19(6): Hofbaur R, Mosr D, Kay AD, Knapp S, Gminr B, Kapiotis S, Wagnr O, Frass M. (2000) Prostaglandin E(1) is abl to incras migration of lukocyts through ndothlial cll monolayrs. Microvasc Rs, 59(3): Andrson SI, Hudlicka O, Brown MD. (1997) Capillary rd blood cll flow and ACtivation of whit blood clls in chronic muscl ischmia in th rat. Am J Physiol. 272(6 Pt 2): H McLoughlin TJ, Mylona E, Hornbrgr TA, Essr KA, Pizza FX. (2003) Inflammatory clls in rat skltal muscl ar lvatd aftr lctrically stimulatd contractions. J Appl Physiol, 94(3):
18 38. Dustrhoft S, Putman CT, Ptt D. (1999) Changs in FGF and FGF rcptor xprssion in low frquncy-stimulatd rat muscls and rat satllit cll culturs. Diffrntiation 65(4): Jass J, Costrton JW, Lappin-Scott HM. Th ffct of lctrical currnts and tobramycin on Psudomonas aruginosa biofilms. J Ind Microbiol Sp;15 (3): Murray TS, Kazmirczak BI. FlhF is rquird for swimming and swarming in Psudomonas aruginosa. J Bactriol Oct;188(19): Toutain CM, Zgans ME, O'Tool GA. Evidnc for two flagllar stators and thir rol in th motility of Psudomonas aruginosa. J Bactriol Jan;187(2): Costrton JW, Ellis B, Lam K, Johnson F, Khoury AE. Mchanism of lctrical nhancmnt of fficacy of antibiotics in killing biofilm bactria. Antimicrob Agnts Chmothr Dc;38(12): Figur 1
FACULTY SALARIES FALL 2004 NKU CUPA Data Compard To Publishd National Data May 2005 Fall 2004 NKU Faculty Salaris Compard To Fall 2004 Publishd CUPA Data In th fall 2004 Northrn Kntucky Univrsity was among
QUANTITATIVE METHODS CLASSES WEEK SEVEN Th rgrssion modls studid in prvious classs assum that th rspons variabl is quantitativ. Oftn, howvr, w wish to study social procsss that lad to two diffrnt outcoms.
Traffic Flow Analysis () Statistical Proprtis. Flow rat distributions. Hadway distributions. Spd distributions by Dr. Gang-Ln Chang, Profssor Dirctor of Traffic safty and Oprations Lab. Univrsity of Maryland,
Cllo Tchnology LG has introducd th NON 2, with nwly dvlopd Cllo Tchnology which improvs prformanc and rliability. Up to 320W 300W Cllo Tchnology Cll Connction Elctrically Low Loss Low Strss Optical Absorption
Rsourc Allocation Abstract This is a small toy xampl which is wll-suitd as a first introduction to Cnts. Th CN modl is dscribd in grat dtail, xplaining th basic concpts of C-nts. Hnc, it can b rad by popl
Studnt Nots Cost Volum Profit Analysis by John Donald, Lcturr, School of Accounting, Economics and Financ, Dakin Univrsity, Australia As mntiond in th last st of Studnt Nots, th ability to catgoris costs
Lctur 6: Th Forign xchang Markt xchang Rats in th long run CON 34 Mony and Banking Profssor Yamin Ahmad xchang Rats in th Short Run Intrst Parity Big Concpts Long run: Law of on pric Purchasing Powr Parity
25 Vol. 3 () January-March, pp.37-5/tripathi EFFECT OF GEOMETRICAL PARAMETERS ON HEAT TRANSFER PERFORMACE OF RECTANGULAR CIRCUMFERENTIAL FINS *Shilpa Tripathi Dpartmnt of Chmical Enginring, Indor Institut
Dhumidifirs: A Major Consumr of Rsidntial Elctricity Laurn Mattison and Dav Korn, Th Cadmus Group, Inc. ABSTRACT An stimatd 19% of U.S. homs hav dhumidifirs, and thy can account for a substantial portion
Basis risk Whn spaking about forward or futurs contracts, basis risk is th markt risk mismatch btwn a position in th spot asst and th corrsponding futurs contract. Mor broadly spaking, basis risk (also
Advrs Slction and Moral Hazard in a Modl With 2 Stats of th World A modl of a risky situation with two discrt stats of th world has th advantag that it can b natly rprsntd using indiffrnc curv diagrams,
Lctur 3: Diffusion: Fick s first law Today s topics What is diffusion? What drivs diffusion to occur? Undrstand why diffusion can surprisingly occur against th concntration gradint? Larn how to dduc th
ustion 3: How do you find th rlativ trma of a function? Th stratgy for tracking th sign of th drivativ is usful for mor than dtrmining whr a function is incrasing or dcrasing. It is also usful for locating
Intrmdiat Macroconomic Thory / Macroconomic Analysis (ECON 3560/5040) Final Exam (Answrs) Part A (5 points) Stat whthr you think ach of th following qustions is tru (T), fals (F), or uncrtain (U) and brifly
Principls of Humidity Dalton s law Air is a mixtur of diffrnt gass. Th main gas componnts ar: Gas componnt volum [%] wight [%] Nitrogn N 2 78,03 75,47 Oxygn O 2 20,99 23,20 Argon Ar 0,93 1,28 Carbon dioxid
Rural and Rmot Broadband Accss: Issus and Solutions in Australia Dr Tony Warrn Group Managr Rgulatory Stratgy Tlstra Corp Pag 1 Tlstra in confidnc Ovrviw Australia s gographical siz and population dnsity
(Analytic Formula for th Europan Normal Black Schols Formula) by Kazuhiro Iwasawa Dcmbr 2, 2001 In this short summary papr, a brif summary of Black Schols typ formula for Normal modl will b givn. Usually
Fr ACA SOLUTION (IRS 1094&1095 Rporting) Th Insuranc Exchang (301) 279-1062 ACA Srvics Transmit IRS Form 1094 -C for mployrs Print & mail IRS Form 1095-C to mploys HR Assist 360 will gnrat th 1095 s for
IBM Halthcar Hom Car Monitoring Sptmbr 30th, 2015 by Sal P. Causi, P. Eng. IBM Halthcar Businss Dvlopmnt Excutiv firstname.lastname@example.org IBM Canada Cloud Computing Tigr Tam Homcar by dfinition 1. With a gnsis
Whits, EE 3 Lctur 0 Pag of 8 Lctur 0: Emittr Followr and Diffrntial Amplifirs Th nxt two amplifir circuits w will discuss ar ry important to lctrical nginring in gnral, and to th NorCal 40A spcifically.
A Thortical Modl of Public Rspons to th Homland Scurity Advisory Systm Amy (Wnxuan) Ding Dpartmnt of Information and Dcision Scincs Univrsity of Illinois Chicago, IL 60607 wxding@uicdu Using a diffrntial
Economy Transdisciplinarity Cognition www.ugb.ro/tc Vol. 16, Issu 1/2013 50-54 Improving Managrial Accounting and Calculation of Labor Costs in th Contxt of Using Standard Cost Lucian OCNEANU, Constantin
C H A P T E R 1 Writing Rports with SAS Prsnting information in a way that s undrstood by th audinc is fundamntally important to anyon s job. Onc you collct your data and undrstand its structur, you nd
Non-Homognous Systms, Eulr s Mthod, and Exponntial Matrix W carry on nonhomognous first-ordr linar systm of diffrntial quations. W will show how Eulr s mthod gnralizs to systms, giving us a numrical approach
Intrnational Association of Scintific Innovation and Rsarch (IASIR) (An Association Unifing th Scincs, Enginring, and Applid Rsarch) ISSN (Print): 79-000 ISSN (Onlin): 79-009 Intrnational Journal of Enginring,
RESEARCH PAPERS IN MANAGEMENT STUDIES SPREAD OPTION VALUATION AND THE FAST FOURIER TRANSFORM M.A.H. Dmpstr & S.S.G. Hong WP 26/2000 Th Judg Institut of Managmnt Trumpington Strt Cambridg CB2 1AG Ths paprs
Air Handling Systms Enginring & chnical Bulltin 81-1-ISD Economic Considrations of Hat ransfr on Sht Mtal Duct Othr bulltins hav dmonstratd th nd to add insulation to cooling/hating ducts in ordr to achiv
Liquidity and Information-Basd Trading on th Ordr Drivn Capital Markt: Th Cas of th Pragu tock Exchang Libor 1ÀPH³HN Cntr for Economic Rsarch and Graduat Education, Charls Univrsity and Th Economic Institut
Gorgia Stat Univrsity ScholarWorks @ Gorgia Stat Univrsity Risk Managmnt and Insuranc Dissrtations Dpartmnt of Risk Managmnt and Insuranc 8--00 Essays on Advrs Slction and Moral Hazard in Insuranc Markt
www.ccsa.ca www.cclt.ca Octobr 2014 Rapid Rviw Sking Safty: Th Bnfits of Gndr-spcific vrsus Co-Educational Thrapy Ky Mssags Sking Safty programming is an approach for addrssing co-occurring substanc us
Th Matrix Exponntial (with xrciss) 92.222 - Linar Algbra II - Spring 2006 by D. Klain prliminary vrsion Corrctions and commnts ar wlcom! Th Matrix Exponntial For ach n n complx matrix A, dfin th xponntial
MEASURING MOOR PARAMEERS Fil: Motor paramtrs hs ar th motor paramtrs that ar ndd: Motor voltag constant (volts-sc/rad Motor torqu constant (lb-in/amp Motor rsistanc R a (ohms Motor inductanc L a (Hnris
AP Calculus AB 8 Scoring Guidlins Th Collg Board: Conncting Studnts to Collg Succss Th Collg Board is a not-for-profit mmbrship association whos mission is to connct studnts to collg succss and opportunity.
24+ Advancd Larning Loan Application form Rmmbr you can apply onlin. It s quick and asy. Go to www.gov.uk/advancdlarningloans About this form Complt this form if: you r studying an ligibl cours at an approvd
STATEMENT OF INSOLVENCY PRACTICE 3.2 COMPANY VOLUNTARY ARRANGEMENTS INTRODUCTION 1 A Company Voluntary Arrangmnt (CVA) is a statutory contract twn a company and its crditors undr which an insolvncy practitionr
Chaptr 3: Entity Rlationship Modl Databas Dsign Procss Us a high-lvl concptual data modl (ER Modl). Idntify objcts of intrst (ntitis) and rlationships btwn ths objcts Idntify constraints (conditions) End
NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA MBA PROFESSIONAL REPORT Th Survivor Bnfit Plan: A Cost-Bnfit Analysis By: Advisors: Scott E. Batty, and Tho Kang Dcmbr 2007 William R. Gats, Raymond E. Franck
Logo Dsign/Dvlopmnt 1-on-1 If your company is looking to mak an imprssion and grow in th marktplac, you ll nd a logo. Fortunatly, a good graphic dsignr can crat on for you. Whil th pric tags for thos famous
Incomplt -Port Vctor Ntwork nalyzr Calibration Mthods. Hnz, N. Tmpon, G. Monastrios, H. ilva 4 RF Mtrology Laboratory Instituto Nacional d Tcnología Industrial (INTI) Bunos irs, rgntina email@example.com
NO. 27 IEA MONOGRAPH High Intrst Rats In Ghana, A Critical Analysis IEA Ghana THE INSTITUTE OF ECONOMIC AFFAIRS A Public Policy Institut High Intrst Rats In Ghana, A Critical Analysis 1 by DR. J. K. KWAKYE
Cloud and Big Data Summr Scool, Stockolm, Aug., 2015 Jffry D. Ullman Givn a st of points, wit a notion of distanc btwn points, group t points into som numbr of clustrs, so tat mmbrs of a clustr ar clos
Microconomics Topic 1: Explain why xchang rats indicat th pric of intrnational currncis and how xchang rats ar dtrmind by supply and dmand for currncis in intrnational markts. Rfrnc: Grgory Mankiw s Principls
hsn uknt Highr Mathmatics UNIT Mathmatics HSN000 This documnt was producd spcially for th HSNuknt wbsit, and w rquir that any copis or drivativ works attribut th work to Highr Still Nots For mor dtails
Ethanolic Extraction of Soyban Oil: Oil Solubility Equilibria and Kintic Studis Christiann E. C. Rodrigus*, Natália M. Longo, Cibl C. Silva, Kila K.. Aracava, Bruna R. Garavazo Sparation Enginring Laboratory
Click to dit Mastr titl styl Click to dit Mastr txt styls Scond lvl Third lvl Natural Gas & Elctricity Prics Fourth lvl» Fifth lvl Glnn S. Pool Manufacturing Support Mgr. Enrgy April 4, 2013 Click Vrso
Nw Basis Functions Sction 8 Complx Fourir Sris Th complx Fourir sris is prsntd first with priod 2, thn with gnral priod. Th connction with th ral-valud Fourir sris is xplaind and formula ar givn for convrting
Intrnational Rviw of Physics (I.R.E.PHY.), Vol. 5, N. 5 Octobr 20 Major Portions in Climat Chang: Physical Approach Jyrki Kauppinn, Jorma. Hinonn, Pkka J. Malmi Abstract h dstroying of rainforsts can warm
IMES DISCUSSIN PAPER SERIES Th Choic of Invoic Currncy in Intrnational Trad: Implications for th Intrnationalization of th Yn Hiroyuki I, Akira TANI, and Toyoichirou SHIRTA Discussion Papr No. 003-E-13
4-226-697-71(1) Micro Satllit Systm Oprating instructions GB CS SA-V315 SA-V312 2000 Sony Corporation WARNING To prvnt fir or shock hazard, do not xpos th unit to rain or moistur. To avoid lctrical shock,
Jun 22 Enpris Rnt Author: Documnt Vrsion: Product: Product Vrsion: SAP Vrsion: Enpris Enpris Rnt 88 88 Enpris Rnt 22 Enpris Solutions All rights rsrvd No parts of this work may b rproducd in any form or
Elctronic Commrc and Comptitiv First-Dgr Pric Discrimination David Ulph* and Nir Vulkan ** Fbruary 000 * ESRC Cntr for Economic arning and Social Evolution (ESE), Dpartmnt of Economics, Univrsity Collg
SUBATOMIC PARTICLES AND ANTIPARTICLES AS DIFFERENT STATES OF THE SAME MICROCOSM OBJECT Eduard N. Klnov* Rostov-on-Don. Russia Th distribution law for th valus of pairs of th consrvd additiv quantum numbrs
Cooprativ Extnsion Srvic Institut of Food and Agricultural Scincs PACKINGHOUSE NEWSLETTER Mark Ritnour Packinghous Nwslttr No. 192 Indian Rivr REC Dcmbr 29, 2000 2199 South Rock Road Ft. Pirc, FL 34945-3138
Applid Mathmatical Scincs, Vol, 00, no 9, 45-49 A Not on Approimating th Normal Distribution Function K M Aludaat and M T Alodat Dpartmnt of Statistics Yarmouk Univrsity, Jordan Aludaatkm@hotmailcom and
Th ffct of a topical inscticid containing prmthrin on th numbr of Culicoids midgs caught nar horss with and without insct bit hyprsnsitivity in th Nthrlands I.J. d Raat i, R. van dn Boom i, ii M. van Poppl
Victor Sazonov (Russia), Dmitry Nikolav (Russia) Thortical aspcts of invstmnt dmand for gold Abstract Th main objctiv of this articl is construction of a thortical modl of invstmnt in gold. Our modl is
Entity-Rlationship Modl Kuang-hua Chn Dpartmnt of Library and Information Scinc National Taiwan Univrsity A Company Databas Kps track of a company s mploys, dpartmnts and projcts Aftr th rquirmnts collction
www.ccsa.ca www.cclt.ca Spring 2015 Canadian Drug Summary MDMA (Ecstasy, Molly) Ky points Th prvalnc of past-yar cstasy us is lss than 1% and has dcrasd by half sinc 2008. 1 in 25 Canadian youth in grads
Introduction to Finit Elmnt Modling Enginring analysis of mchanical systms hav bn addrssd by driving diffrntial quations rlating th variabls of through basic physical principls such as quilibrium, consrvation
Th Dvlopmnt of a Small Scal Class A Fir Tst A Chattawayt, G G Cox, S R Prc & D J Spring Kidd Intrnational, Mathisn Way, Colnbrook, Slough, SL3 OHB UK Tl: +44 1753 683245 Fax: +44 1753 683810 1. Introduction
Unit Stats Gnral Accounting Offic Washington, DC 20548 Halth, Eucation, an Human Srvics Division B-285141 April 21, 2000 Th Honorabl Charls B. Rangl Ranking Minority Mmbr Committ on Ways an Mans Hous of
Govrnmnt Spnding or Tax Cuts for Education in Taylor County, Txas Ian Shphrd Abiln Christian Univrsity D Ann Shphrd Abiln Christian Univrsity On Fbruary 17, 2009, Prsidnt Barack Obama signd into law th
Paralll and Distributd Programming Prformanc! wo main goals to b achivd with th dsign of aralll alications ar:! Prformanc: th caacity to rduc th tim to solv th roblm whn th comuting rsourcs incras;! Scalability:
.4 Eponntial Functions: Diffrntiation an Intgration TOOTLIFTST: Eponntial functions ar of th form f ( ) Ab. W will, in this sction, look at a spcific typ of ponntial function whr th bas, b, is.78.... This
3 rd Intrnational Confrnc on Industrial Enginring and Industrial Managmnt XIII Congrso d Ingniría d Organización Barclona-Trrassa, Sptmbr 2nd-4th 2009 Global Sourcing: lssons from lan companis to improv
Singapor Managmnt Univrsity Institutional Knowldg at Singapor Managmnt Univrsity Rsarch Collction L Kong Chian School Of Businss L Kong Chian School of Businss 10-2008 Ral-Tim Evaluation of Email Campaign
Far Fild Estimations and Simulation Modl Cration from Cabl Bundl Scans D. Rinas, S. Nidzwidz, S. Fri Dortmund Univrsity of Tchnology Dortmund, Grmany firstname.lastname@example.org email@example.com Abstract
CHAPTER c. ROOTS OF EQUATIONS A. J. Clark School o Enginring Dpartmnt o Civil and Environmntal Enginring by Dr. Ibrahim A. Aakka Spring 00 ENCE 03 - Computation Mthod in Civil Enginring II Dpartmnt o Civil
CPS 22 Thory of Computation REGULAR LANGUAGES Rgular xprssions Lik mathmatical xprssion (5+3) * 4. Rgular xprssion ar built using rgular oprations. (By th way, rgular xprssions show up in various languags:
Onlin Pric Comptition within and btwn Htrognous Rtailr Groups Cnk Kocas Dpartmnt of Markting and Supply Chain Managmnt, Michigan Stat Univrsity firstname.lastname@example.org Abstract This study prsnts a modl of pric comptition
Surfac wav acclrator basd on silicon carbid (SWABSiC) V. Khudi, S. Trndafilov, Kamil B. Alici P.I. Gnnady Shvts Th Univrsity of Txas at Austin V. Yaimno, M. Babzin, M. Fdurin, K. Kusch BNL/ATF Lasr Bam