•The paper analyzes the flapper-nozzle type pneumatic valve with two ports in the frequency domain.•The valve is a part of the pneumatically driven parallel robot platform.•The system is observed as ...a parallel connection between the fixed orifice, the nozzle and the chamber.•The describing function is reduced to the unit gain and does not depend on the amplitude of the input signal.•The system becomes linear and is described only by means of the frequency response.
This paper addresses the mass flow rate characteristic of a pneumatic valve set in the frequency domain. The valve set consists of a flapper-nozzle type valve and a constant isothermal volume chamber. It represents a part of the control system of the pneumatic parallel robot platform. Different flow regimes are analyzed because of air compressibility. The nonlinearity originating from the mass flow rate characteristic is approximated by the sinusoidal input describing function. Analytical determination of the describing function in a general case is not possible. However, the equivalent nonlinearity and the corresponding Hammerstein model can be introduced for a certain flow regime. In that case, the describing function of nonlinearity can be determined analytically. Amplitude and frequency responses show that the nonlinearity becomes more prominent at smaller frequencies and higher amplitudes of the exogenous signal. Analytical results show good agreement with the experimental results.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
Traumatic thumb amputation can have devastating effects on residual hand function. When replantation is not possible, thumb reconstruction is often performed in a delayed manner and may require ...multiple stages. Furthermore, reconstruction techniques often require microsurgical skills and equipment, which are not readily available at all institutions. This case series illustrates our technique for immediate osteoplastic thumb reconstruction following traumatic amputation.
This is a case series involving all patients who sustained unreplantable thumb amputations and underwent immediate osteoplastic thumb reconstruction with bone autograft and pedicled groin flap by the senior author from September 2016 through August 2018.
Five patients underwent immediate osteoplastic thumb reconstruction during the study period. Total operative time for the initial osteoplastic reconstruction averaged 158 minutes (range 96-290 minutes). In addition to flap division surgery, patients underwent an average of 1.2 revision procedures (range 0-2), primarily for debulking and hardware removal. Patients achieved an average gain in length of 3.3 cm compared with the maximum anticipated length with revision amputation at the time of injury, and had stable clinical outcomes for a minimum of 12 months.
Osteoplastic thumb reconstruction is a useful technique for thumb reconstruction for select patients following traumatic thumb amputation. Advantages of this approach include shorter overall operative times and hospital length of stay, minimal donor site morbidity, and a straightforward, reproducible technique.
Plastic and reconstructive surgery has a well-recognized history of disruption and innovation. It remains unclear, however, how the specialty's priority on innovation materializes into ...commercialization or bench to bedside led by plastic surgeons.
Our analysis utilized Pitchbook (Seattle, Wash.), a market database of companies and investors, for ventures that have designed innovations related to plastic and reconstructive surgery. Companies were categorized into 5 focus areas: provider (outpatient surgical or hospital entity), aesthetics (cosmetics/injectables), devices (instrumentation, lasers, implants), regenerative medicine (tissue engineering/wound healing), and software (digital solutions). Company websites, LinkedIn (Sunnyvale, Calif.) profiles, and Crunchbase (San Francisco, Calif.) were reviewed to determine the leadership roles of plastic surgeons.
Plastic surgeons primarily serve as advisors, as opposed to founders or chief executive officers (CEOs). Our analysis additionally found that provider and software solutions had a greater degree of plastic surgeon-led leadership, whereas regenerative medicine and device innovation remains less frequented. There was a relatively balanced representation of academic and private plastic surgeons in entrepreneurial pursuits.
Plastic surgeons typically serve as board advisors, as opposed to founders and CEOs. Reasons for disengagement from leadership roles may include satisfaction with clinical work, time constraint, lack of business knowledge, financial constraint, and opportunity cost associated with starting a venture. To promote participation in innovation, future studies should explore tangible ways to engage in such opportunities. In doing so, plastic surgeons can own the "organ" of innovation, and continue to contribute to the legacy and the advancement of the specialty.
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