experienced cosmetic dermatologists share advice on...

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Variable Tension, Large Deflection Ideal String Model For Transverse Motions Namik Ciblak Department of Mechanical Engineering Yeditepe University, Istanbul, Turkey E-Mail: [email protected] http://me.yeditepe.edu.tr October 4, 2013 Abstract In this study a new approach to the problem of transverse vibrations of an ideal string is presented. Unlike previous studies, assumptions such as constant tension, inextensibility, constant crosssectional area, small deformations and slopes are all removed. The main result is that, despite such relaxations in the model, not only does the final equation remain linear, but, it is exactly the same equation obtained in classical treatments. First, an ”infinitesimals” based analysis, similar to historical methods, is given. However, an alternative and much stronger approach, solely based on finite quantities, is also presented. Furthermore, it is shown that the same result can also be obtained by Lagrangian mechanics, which indicates the compatibility of the original method with those based on energy and variational principles. Another interesting result is the relation between the force distribution and string displacement in static cases, which states that the force distribution per length is proportional to the second spatial derivative of the displacement. Finally, an equation of motion pertaining to variable initial density and area is presented. Keywords: Ideal String, Transverse Vibration, Large Deflection, Variable Ten- sion 1 Introduction The well known ideal string model used for analysis of transverse string vibrations has been around for almost three centuries. This historical approach is also used as one of the first examples in elementary or advanced texts on partial differential equations (PDE) and mathematical physics. The resulting PDE is usually solved by Bernoulli’s separation method which yields two second order linear ordinary differential equations, one for spatial dimension and one for temporal. For certain boundary conditions the total solution can be constituted in form of Fourier series. The uniqueness of the solution is also proven without much difficulty [1]. This famous wave equation is y xx = 1 c 2 y tt (1) where subscripts denote partial differentiation. Aside from being one of the simplest and exemplary PDEs, the importance of the ideal string equation also stems from a few other reasons. First, the analytical solutions 1 arXiv:1310.1019v1 [physics.gen-ph] 28 Aug 2013

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Page 1: Experienced cosmetic dermatologists share advice on ...bmctoday.net/practicaldermatology/pdfs/PD0706feaCosmetics.pdf · American Society for Cosmetic Dermatology & Aesthetic Surgery

36 Practical Dermatology July 2006

Experienced cosmetic dermatologists

share advice on deciding

whether or not to offer

cosmetic services and how

to actively plan for success.

By Ted Pigeon, Associate EditorBy Ted Pigeon, Associate Editor

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It’s sometimes easy to forget that dermatology receivedofficial recognition as a specialty in the US just 74 yearsago. Within this context, cosmetic dermatology iswithout doubt a nascent field. Yet already it is makinga significant impact on the practice of dermatology and

the public perception of the specialty. Cosmetic services,devices, and products now offer physicians and patients awide variety of treatments for a laundry list of indications.Emerging studies continue to detail the seemingly endlessuses for Botox and filler agents, while new types of lasers arebeing offered to dermatologists. As technological advancescontinue and possibilities grow, dermatologists that offer cos-metics or are currently pondering the possibility face difficultquestions as they aim to develop a cosmetics philosophy andmake the informed practicedecisions that suit their patientsas well as their own interests indermatology practice.

Difficult QuestionsOne of the major issues facingdermatologists today, especiallythose just setting out to inte-grate cosmetic procedures intotheir practices, is to what extenta physician is obligated to offercosmetics—if at all. A few gen-eral trains of thought exist. Thefirst holds that cosmetic derma-tology is not a worthwhile pur-suit, either because of insuffi-cient physician/patient interestor ideological concerns. The sec-ond suggests the dermatologistshould offer a select number ofprocedures that he or she choos-es or wishes to specialize in, e.g.Botox or chemical peels. Thealternative to this approachwould be to offer as broad aspectrum as one can, thereby giving patients the widest possi-bilities in selecting procedures.

Of course, each ideology has advantages and disadvantages(not to mention degrees of variability between them), butaccording to Joel Schlessinger, MD, founding member of theAmerican Society for Cosmetic Dermatology & AestheticSurgery and in private practice in Omaha, NE, it is importantfor dermatologists to consider all possibilities before makingdecisions, not only about which approach to advocate,including whether or not to enter cosmetics at all. “The ques-

tion of whether to offer cosmetics is a personal decision thateach dermatologist has to make,” says Dr. Schlessinger, whoemphasizes that the patients he sees in his practice aren’t allthat different from the general dermatology patients seenevery day, except that they have slightly higher expectationsas a group. Additionally, many dermatology practices don'toffer a setting that is particularly conducive to a cosmeticpractice, he reminds, which highlights the number of changesa physician often must make in order to properly promoteand administer cosmetic treatments and procedures.

Expansion of the field of cosmetics makes it increasinglydifficult for dermatologists to offer as broad a canvas of pro-cedures as many would like. According to Sue Ellen Cox,MD, Clinical Associate Professor of Dermatology at the

University of North Carolinaand medical director ofAesthetic Solutions in ChapelHill, NC, it all comes down tothe individual dermatologistand what he or she can handle.“When somebody is first get-ting into cosmetics, they areprobably going to offer the pro-cedures that often get the bestresults,” she says. “They maynot want to put a big expendi-ture out there if their practicemay never turn into a cosmeticspractice. They are not going tostart with the lasers, but insteadBotox and fillers.” From there,Dr. Cox advises, the practicecan then build its cosmeticsstature to wherever the derma-tologist is willing to take it. “Itdepends on the practitioner andhow much time he or she wantsto devote to it,” she says.

Dr. Cox acknowledges thatthe dermatologist who main-

tains a general dermatology practice and is interested in cos-metics may find it difficult to offer a wide selection of cosmet-ic procedures. Nevertheless, she says, offering various proce-dures can be very beneficial. “You have a bigger palette to drawfrom so that you don’t have just one thing to offer patients,”she notes. According to Dr. Cox, variety allows treatment ofdifferent conditions in any number of ways; not everybodybenefits from the same individual procedure. Therefore, havingaccess to many different options increases flexibility in yourapproach to treating patients and getting the best results.

July 2006 Practical Dermatology 37

“The question of whetherto offer cosmetics is a

personal decision that each dermatologist has to

make,” says Dr. Schlessinger, whoemphasizes that the

patients he sees in his practice aren’t all that

different from the general dermatology

patients seen every day.

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The potential downside to this approach is that dermatolo-gists may not be able to devote themselves as much as theywould like to individual procedures, which can lead to a ‘dab-ble’ approach to cosmetics. “‘Dabbling’ is something that isbest left to a non-cosmetic oriented individual,” says Dr.Schlessinger. He adds that offering cosmetics is a mind-set thatshould be pervasive throughout the entire practice, from thefront desk to the physicians themselves. “Although it is veryeasy to offer a few services—and a reasonable way to startout—it is best to commit to the delivery of a full-scale prod-uct, whether it is sclerotherapy, Botox, or a laser procedure.”

No matter the extent to which a dermatologist invests hisor her practice in cosmetics, both Dr. Schlessinger and Dr.Cox stress the need for commitment and to avoid dabbling.“What most dermatologists don’t realize is the effort it takesto be successful in this endeavor,” says Dr. Schlessinger. “Wesee many ‘fly by night’ operations that are opening in ourarea, run by ghost doctors and PAs that haven’t been success-ful comparatively. That doesn’t mean that these ventureswon’t eventually be successful, but they can’t be as successfulif they are just a part time effort with a passive owner.”

New TechnologiesCertainly some derma-tologists will choosenot to offer cos-metic services, adecision thatexperts agree isreasonable and,for some prac-tices, wise. Butthe next chal-lenge ahead of

the dermatologist who elects toincorporate cosmetics is determin-

ing how to give their patients the bestresults and consistent quality while keeping up to date

with new and effective procedures and devices. This isnot easy, according to Dr. Cox, because so much is outthere, and it is difficult to determine what will reallyadd to your practice and what will not. “In terms ofmy approach with new technology, I’m always a little

bit skeptical,” she says. “The press will often get infor-mation out about things before any actual studies have

been done.” Dr. Cox warns that dermatologists can’t embraceevery kind of new technology because much of it is not reli-able and sometimes, there is simply no reliable data.“Recently, at my practice, we had a laser company come witha new laser machine, calling it the ‘next great step,’ and whenI asked for their studies, they had company white papers butno controlled studies. Many of these procedures and devicesmay sound great, but some of them have no peer-reviewedjournal articles or studies verifying their claims.”

Precisely because hype can exceed reality, Dr. Cox recom-mends dermatologist reign-in their interest in every newdevice or technology that comes along. “For example, whenThermage came out, there was a big media push and a lot ofhype, but much of the hype preceded the results in that theyweren’t initially sure which parameters to use.” Dr. Coxpoints out that there were patients who were getting indenta-tions, as well as depression from melting fat. “It wasn’t untila couple years later that anyone realized that they should beusing lower fluences and multiple passes. Fifty percent ofpeople get minimal results, and if you’re paying a couplethousand dollars for something that’s not going to givenoticeable results, that actually does not build your practice.”

It is the dermatologist’s job to know what works best forpatients, because they trust you to take this seriously, Dr. Coxsays. By avoiding much of the unstudied, over-hyped devices

and procedures, you will earn patients’ trust, which willbuild your reputation as a cosmetic dermatologist, sheadds. That reputation is something you cannot afford todamage, she notes. “I think the bottom line with newtechnologies is that you certainly want to be on the cut-ting edge and serve your patients, but you really want tolook carefully at the new technologies and not jump ona bandwagon that’s fed by the media. You do have to take

a more academic view and do the homework involved.”

Patient DemandThe question of patient demand leads back to the questionof what dermatologists are obligated to offer their patients:as much as possible or a select offering of areas of the derma-tologists expertise? This becomes a more relevant concernwhen considering the economic need and demand for specif-ic procedures. “This is impossible to gauge until you havethrown your hat in the ring,” says Dr. Schlessinger.“Obviously, there are certain things that can foretell doom,such as setting up a cosmetic practice in a significantlydepressed economical area or an area with age demographicsthat are out of sync with cosmetic procedures (too old ortoo young).”

In terms of individual procedures, it is obviously impor-tant to know where the demand is, what your patients want,

The Cosmetics Question

38 Practical Dermatology July 2006

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and what the new hot topics are in cosmetic medicine. To dothis, Dr. Cox recommends that you attend scientific, educa-tional conferences, such as those offered by the AmericanSociety of Dermatologic Surgery (ASDS) and AmericanAcademy of Dermatology (AAD) meetings.

Dr. Schlessinger notes, “I have always been one to do lessrather than more research on the patients’ desires initiallybecause they don’t always know what they want. On the otherhand, it is extremely important to have good judgment if youuse this method.”

Dr. Cox suggests that you try to understand your patientsand look to the experiences of others. “I’m usually not thefirst person to buy the new toy on the block. I’d rather givemy patients what works, what’s tried and true, because myreputation depends on it,” Dr. Cox says. She adds that youhave to present new technologies to the right patient popula-tion, another reason knowing your patients may be helpful.

A Growing SplitAside from questions of how to integrate cosmetics into yourown dermatology practice, other cosmetics controversies war-rant consideration. For example, within the specialty of der-matology, some view cosmetics as if it lacks medical value.Dr. Cox points out that many of these detractors are olderdermatologists. Dr. Schlessinger agrees. “There is definitely asplit, and it is growing rather than shrinking,” he says. Healso acknowledges that younger dermatologists may be doingtoo much in cosmetics, which may be contributing to theolder dermatologists’ reservations. “A balance has to be struckbetween doing all or none in a practice,” he notes.

Mainstream news media coverage, which often dictatesthe general public’s knowledge of cosmetics, doesn’t helpthese matters, says Dr. Cox. Whereas exposure would be pre-

sumably good for the specialty, what the media presents ishardly representative of cosmetic dermatology, she notes. Thefalse image of cosmetics not only misguides the public, butalso further fuels the growing split within the specialty.

Cosmetic dermatologists must not only educate their non-cosmetic peers, they must build and protect the image of thespecialty in the public. “I think there is a negative outlooktowards practitioners that aren’t dermatologists but still per-form the procedures that we do,” Dr. Cox says. Those whoprovide services without proper qualifications give a badname to dermatologists who approach these matters serious-ly. “For example, if somebody receives laser hair removal at aspa and dies of lidocaine toxicity, many patients will becomevery nervous when they come to our practice for laser hairremoval because they think that the same thing is going tohappen to them.” But, she notes, such things usually don’thappen to trained physicians.

Many heavily advertised establishments, such as day spasthat aren’t managed by a board-certified dermatologist, offerBotox injections among other procedures. Dr. Cox claimsthat these establishments do a disservice to the people whovisit them as well to dermatologists. The real danger, Dr. Coxsays, is that people form their perceptions of cosmetic proce-dures based on their visits to spas and what is seen on nation-al morning shows and advertisements. “I sometimes seepatients who tell me they don’t want Botox, because it didn’twork for them when they received it at the spa, when in factmany of these spas don’t know how to administer Botoxproperly and often dilute it,” Dr. Cox says.

As for the split within the dermatology community, Dr. Coxsays this is likely due to how one decides to approach cosmeticsand whether or not an individual truly strives to help theirpatients and broaden the scope of knowledge within the derma-

July 2006 Practical Dermatology 39

Should widespread availability or lack of certain procedures dictate what procedures a dermatologist shouldoffer his or her patients?

Local availability (demand and/or competition) is extremely important in choosing what cosmetic services tooffer, according to Dr. Schlessinger. But it can be looked at from many standpoints. “For example, the benefitof widespread availability is that patients know what the procedure is and the dermatologist introducing thatprocedure to their practice doesn’t have to spend as much money and time promoting it,” he says.

“On the other hand, many patients are already ‘taken’ by other practitioners if it is widespread. It is impossi-ble to always be first to do something and it is an absolute that if you introduce everything first, you will beburned eventually by something that doesn’t pan out. So, all things considered, there is no right or wrongtime to enter the fray!”

When to Get Involved

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tology field. Dermatologists who negatively view cosmetics oftenseem to feel that if you are not taking care of a disease, then youaren’t doing your job as a physician. “There’s always the old say-ing, ‘Is it disease or is it desire?’” according to Dr. Cox, but cos-metic dermatology does in fact serve medical purposes andrequires the abilities of a trained physician.

Cosmetic procedures don’t necessarily have to be sostrongly divided from general dermatology. In fact, both Dr.Cox and Dr. Schlessinger claim that cosmetics can be veryuseful for expanding certain treatments and procedureswithin general dermatology—a very effective way of break-ing into cosmetics for dermatologists in general practice.“For your patients with rosacea, consider a pulsed-dye laser,”says Dr. Cox. As your experience and reputation grow, thenpatients will come and ask you more about some of the othercosmetic procedures like Botox, fillers, other types of lasertreatments, body peels, and other procedures.

A Changing Outlookegardless of individual attitudes regarding cosmetic derma-tology, Dr. Cox stresses that much tension within the der-matology community may be relieved if all who practicedcosmetics preserved and defended their serious, scientificapproach. Whether it’s knowing what technologies ordevices to use or what procedures to offer, the actions ofdermatologists impact the reputation of cosmetic dermatol-ogy.

So far, Dr. Schlessinger is encouraged by what he hasseen in recent years and remains positive for the future of

cosmetics. “There is a significant shift in how these proce-dures are now being delivered and that has made them moreacceptable in the public and professional opinion,” he says.Furthermore, Dr. Cox adds, “As dermatologists, we reallyhave to embrace these procedures because we’re the onesthat have developed them.”

Ultimately the dermatologists who skillfully performprocedures have made cosmetics so acceptable and medical-ly viable. If dermatologists continue that trend, cosmeticswill continue to grow and may soon win over its detractors.“It is the knowledge behind the cosmetics that makespatients seek our care as dermatologists rather than going toa plastic surgeon or a day spa for treatment,” says Dr.Schlessinger. “This will always come down to quality.Quality is measured by the passion for delivery of healthcarein an effective and patient friendly manner.”

Both Dr. Schlessinger and Dr. Cox remind colleaguesthat finding balance is important, and dermatologists mustweigh what is best for their patients and the reputation oftheir field when exploring the possibilities that cosmeticscan offer. Says Dr. Schlessinger, “The best part of derma-tology is the ability to devote one’s energy to areas thatinterest and stimulate your curiosity. If Cosmetics fits thisdescription, it is a great idea to start performing variousprocedures and see if it suits you.”

1. Finzi E, Wasserman E. Treatment of Depression with Botulinum Toxin A: A Case Series. Journal of Dermatologic

Surgery. May 2006. 32: 5

2. Finn J, Cox S. Social Implications of Hyperfunctional Facial Lines. Journal of Dermatologic Surgery. May 2003

The Cosmetics Question

Recently, a study has received wide coverage in the mainstream media that, though marred by limitations,may highlight a medical basis for cosmetic dermatology and put a more positive face on the field. The studyfound that Botox may cure severe depression,1 which some in the dermatology community have speculatedfor some time. Drs. Schlessinger and Cox sound off on this study and the potential use of Botox for othermedical conditions.

Dr. Schlessinger: “This particular study is very rough. It isn’t a controlled study and has many flaws, but isvery interesting to see. Botox has many uses we are just now learning about and I expect this study to be fol-lowed up on in a more rigorous manner in the future.”

Dr. Cox: “I find this study very interesting. We did an article2 on patient perception of Botox and satisfaction,how people feel better about themselves. I think it makes sense that someone who is depressed that looks inthe mirror and looks better may improve depression. But as interesting as this study is, there is much aboutBotox that we don’t yet understand and are learning about, such as how it treats migraines and tensionheadaches. There may be many factors that likely go into the results of this study. The treatment possibilitieswith Botox are fascinating. We are just now seeing the tip of the iceberg.”

The Many Faces of Botox

40 Practical Dermatology July 2006